pcsd newsletter-special edition-2007

“Knowing is not enough; we must apply.Being willing is not enough; we must do.”

Leonardo Da Vinci

“Knowing is not enough; we must apply.Being willing is not enough; we must do.”

Leonardo Da Vinci

Downstream Upstream Control Instrumentation

A Patent on HydrogenPurification Optimization

System is Granted

Computer Modelingof rate of change withapplications in PipelineProtection and check

valves economic selection

Yanbu‘ Gas PlantDynamic Optimizer

Implementation

Key Elements for Oil &Gas Wireless Networks

Issue No. 8 Special Edition 2007 Leaders in process engineering and automation

©C

op

yrig

ht

2007

,Sau

diA

ram

coA

llri

gh

tsre

serv

ed

Message fromVice President

It gives me a great pleasure to reach out to our

customers in this issue of the Process and

Control System Department (P&CSD)

newsletter. Our goal at P&CSD is to

communicate our dedication to the continuous

improvement of facilities' business performance.

The development of new leading edge technologies is one of our main

drivers in the engineering strategies to achieve operational excellence.

We focus on deploying proven process and control technologies that will

give our company a competitive edge. As the main stakeholders, our

customers’ participation and collaboration are essential to the success of

the development and implementation of these technologies.

We are all aware of the global shortage in technically skilled job

candidates. Engineering Services is leading an initiative to develop that

talent in-Kingdom using technical competency maps. These maps focus on

required technical competencies that can be acquired by attending

training courses, achieving professional certifications, participating in

technical exchange forums and professional society events, as well as

learning practical engineering skills in the field. Technical competency

maps will guide the development of more than 5000 engineers in our

surface facilities. By remaining competitive, we will improve the lives of

our people, diversify and grow our economy, and ensure that Saudi

Aramco will remain a leader in the oil & gas industry.

Isam Al Bayat

“We all

committed to

support our

facilities with

leading edge

technologies to

achieve

operational

excellence.“

Suggested topics and related technical articles for thisnewsletter are encouraged and welcome, and may besubmitted to Abdulaziz Tijani, EOB, E-3410, Dhahranor e-mailed to [email protected]

Process & Control SystemsDepartment Newsletter

Contents

Process & Control Systems Newsletter is publishedBi-annually by the Process & Control Systems Department

P&CSD TechnologyPartnership Meeting withYR and RTR

7

Saudi Aramco’s FuelQuality Roadmap

8

Troubleshooting YRCyclemax Regenerator

Catalyst Blow out 16

P&CSD Supports LocalProfessional

Societies: AIChE-SAS

21

TORR Technology forProduced Water

Treatment

25

A Patent on HydrogenPurification Optimization isGranted

11

Application of FlareGas Recovery

Systems in SaudiAramco facilities

12

JRD/FCCU MTC TechnologyEvaluation by FCC AspenKinetic Model

Distillation Workshop

15

20

Rate of ChangeModeling22

0

1000

2000

3000

0.6

0.8

1

1.20

20

40

60

80

100

120

ReImpReImp

ReImpReImp

ReL

ReL

ReL

ReL

0

1000

20003000

0.6

0.8

1

1.20

20

40

60

80

100

120

ReG

ReG

ReG

ReG

01000

20003000

0.6

0.8

1

1.20

50

100

150

200

250

01000

20003000

0.6

0.8

1

1.20

50

100

150

200

250 Basket Impeller Column:New Approach

28

Key Elements for Oil & GasWireless Networks

Optimizing Projects with aMain Automation Contractor

Yanbu‘ Gas PlantDynamic OptimizerImplementation

Automatic ValveCharacterization – Whydidn’t we think of that?

Data Validation andReconciliationA Crucial Technology forProcessing Plants

Alarm System Improvementat AINDAR GOSP-2

Process AutomationFocus Team Update51

43

30

32

38

40

42

Advanced Multivariable &Regulatory Control

Performance Monitoring

36

Industrial Wireless LANSecurity For Oil & GasProcess AutomationNetworks

48

Engineering theFuture

52

Industrial TimeSynchronization

44

HOT SPOT

Safety of the Issue54

Trim Integrity forCompressor Anti-

surge Valves

46

4

V I S I O N - T o b e c o m e l e a d e r s i n p r o c e s s e n g i n e e r i n g a n d a u t o m a t i o n !

Do you ever wonder how our Saudi Aramco

innovators come up with such good ideas? Are they

born inventors, bred with special imagination? We

think not. Our view is that innovation in Saudi Aramco

is much like it was in Thomas Edison’s day, “90%

perspiration and 10% inspiration”.

Now you may ask, where does all that perspiration

come from? Well, in our view, a large part of it comes from an

innovator’s early years working at the plant, dealing with

process and control problems every day — day after day. You

work and expend so much energy that the process and its

problems are burned into your consciousness. And guess what,

that’s a good thing! Because in the end, all those years of

perspiration make you what you are — an experienced

specialist with a keen understanding of your plant and its

problems.

Now here is where the innovation part comes in. If that

experienced specialist keeps a sharp eye out — he will

ultimately come across some new technology, gadget, or

combination — that can solve one of those problems.

Sometimes the technology is already applied somewhere else,

and the innovation is applying it to your application.

Sometimes it’s combining multiple technologies into one to

Letter from the Team“The link between Innovation,

Plant Experience, and Hard Work”

Abdulaziz Tijani

Omar Halawani

Jim Sprague

Jim Anderson

Newsletter team: Abdulaziz Tijani, Omar Halawani, Jim Sprague, Jim Anderson

Process & Control Systems Department Issue No. 8 – Special Edition 2007

5

M I S S I O N - W e i n n o v a t e a n d o p t i m i z e o p e r a t i o n s f o r i m p r o v e d p e r f o r m a n c e t h r o u g h l e a d e r s h i p a n d p r o f e s s i o n a l s e r v i c e s i n p r o c e s s e n g i n e e r i n g a n d p r o c e s s a u t o m a t i o n !

come up with a solution. The next important step is to sell and

implement that solution. Innovation thrives on risk and change.

It is important to understand that new ideas and solutions come

from an attitude, an environment, and a culture that embraces

change.

We know that the world is changing faster than it ever

has before and that everyone is part of that change. The old

saying of “I paid my dues” has become as obsolete and

outdated as the typewriter. Today, as an engineer, your dues are

paid daily. This means that each of us as a customer, supplier, or

employee is being evaluated on a daily basis with an ever

changing measurement. The key is to stay on top in our field

through continuous learning and updating our experience and

knowledge. Saudi Aramco’s learning organization initiatives

can certainly help.

In the end, innovation comes from the following:

• the experienced and knowledgeable engineer with

• watching out for solutions while

• anticipating change and managing risks.

So, for those of you who are gaining work experiences

– and that should include all of us – you are Saudi Aramco’s next

innovators. Just make sure you keep your eyes open for the

solutions.

Remember — rarely does innovation just happen:

instead, it is nearly always born in the struggle to solve a

problem. Sometimes that innovation solves a completely

different problem in a very unanticipated way.

Sincerely,

P&CSD Newsletter Team

“It is

important to

understand that

new ideas and

solutions come

from an

attitude, an

environment,

a culture that

embraces

change..”



Licensure and certification are the mark of a professional. It demonstrates a commitment to the high standards of

professionalism to which the engineering profession subscribes.

Licensure and certification are important because they demonstrate the accomplishment of a set of standards to which

all engineering professionals recognize. The following engineers in P&CSD carry professional engineering

licenses/certifications in various areas that demonstrate their accomplishments to internationally recognized standards.

Other engineers are presently pursuing licenses/certifications.

Professional Engineers in P&CSD

Name Unit License/Certification

I n s t r u m e n t a t i o n , C o n t r o l & A u t o m a t i o n

Jim E. Anderson APCU Certified Automation Professional (CAP), ISA

Steve Wagner APCU P.E. (Canada)

Henry Chan APCU P.E. (Ontario, Canada)

Mohammed Salim CMU MIET CEng (Member of Institute Engineering &Technology - Chartered Engineer)

Zia Soofi CMU P.E. (Texas, USA)

Ralph Hartman IU P.E. (Texas, USA)

Doug Esplin PASU P.E. (Utah, USA)

Farrukh Chawla PASU P.E. (Ontario, Canada)

Hashim Ghalib PASU Certified Automation Professional (CAP), ISATüV/CFSEGB Certified Functional Safety Professional

Austin Brell PASU P.E. (Chartered Engineering License with European Counsel of IChemE),TUV Certified Functional Safety Professional

C o m p u t e r N e t w o r k i n gAbduladhim, Abdullatif CCNU Registered Communications Distribution

Designer, by BICSI

Abdullah Nufaii CCNU Certified Wireless Network Administrator (CWNA)

Mohammed Saeed CCNU Certified Wireless Security Professional (CWSP),Cisco Certified Design Professional (CCDP),Cisco Advanced Wireless LAN Specialist (CAWDS),Cisco Certified Design Associate (CCDA),Cisco Certified Network Associate (CCDA)

Soliman Walaie CCNU Certified Wireless Networks Professional (CWNP)

P r o c e s s E n g i n e e r i n gGene Yeh DPED P.E. (Louisiana, USA)

Sam Zoker DPED P.E. (Texas, USA)

Prasad Pantula DPED P.E. (Corporate member for Engineer’s Australia)

Gabriel Fernandez OPU P.E. (Alberta, Canada)

Jack Dempsey P&SU Chartered Engineer Registrant for the EngineeringCouncil (UK)

Pierre Crevier UPED P.E. Chemical Engineer (Alberta, Canada)

Saleh Mulhim UPED P.E. (Texas, USA)

Yuv Mehra UPED P.E. (Texas & California, USA)

6 Process & Control Systems Department Issue No. 8 – Special Edition 2007

7


The meetings were organized to promote atechnology culture among refinery personaland provide a platform for engineers tobrainstorm new technologies that could bedeployed in a partnership between therefineries and P&CSD. Another goal was toincrease the awareness of Saudi Aramco’stechnology program.

At the meetings, the Research and Development Center’sTechnology Management Division presented an overviewof the center’s technology program to encourage futureparticipation by employees attending the meetiing.P&CSD representative then discussed three newtechnologies that were successfully implemented at thetwo refineries after P&CSD evaluation, and a Yanbu‘Refinery representative talked about new technologiesthat have been implemented at that refinery.

Fruitful brainstorming sessions conducted at the meetingsidentified more than 70 technical items important to thetwo refineries. The items were categorized, and 11 were

selected for further evaluation through an EngineeringService Agreement (ESA) between the two refineries. Thebrainstorming sessions in YR and RTR were facilitated byEngineering Services’ performance consultant and theleadership center in Dhahran.

Forty-five engineers participated in the Yanbu’ Refinerymeeting from Saudi Aramco, Saudi Aramco MobilRefinery (Samref), Saudi Aramco Lubricating Oil RefineryCo. (Lubref), American company Honeywell andHoneywell subsidiary UOP. The Ras Tanura meeting wasattended by 33 engineers.

Both meetings were coordinated by MohammadBalamesh and Saeed Al-Alloush from P&CSD’s CatalyticConversion Unit.

P&CSD Technology Partnership Meeting with YR and RTR

Right: Brain Storming Session atRastanura Refinery

Below: Yanbu‘ Refinery Gathering

P&CSD held one-day “Technology Partnership Meetings” in May and June at Yanbu‘

and Ras Tanura refineries, in line with Engineering Services business line’s strategic

initiatives to accelerate technology exploitation.

7Process & Control Systems Department Issue No. 8 – Special Edition 2007


Saudi Aramco’s Fuel Quality RoadmapAuthor: Walid A. Al-Naeem

This team along with a reputable consultancy firm IFQC(International Fuel Quality Center) has done extensivedata gathering and analysis to develop the roadmap. Themain parameters that are affected by the roadmap is areduction in sulfur content in both the gasoline and dieselproducts to 50 ppm & ultimately to 10 ppm, a reductionin the gasoline benzene to 1.0 vol. % or less, and areduction in benzene aromatic contents to 35 vol. %.These reductions is planned to take place at differentstages of the roadmap.

Those stages are:

Step 1: Immediate operational changes that do not

require capital investments.

Step 2: Changes that require capital projects and can

be implemented by 2013.

Step 3: More stringent specifications that require

additional capital projects to step 2 and can

be implemented by 2016.

BackgroundToday, the world’s policy makers and business leaders areincreasingly in agreement that climate change isoccurring and it has to be addressed. As a responsiblecorporate citizen, Saudi Aramco is committed to reduce

A cross-functional team composed of EPD, FPD, RTSD, OSPAS, and chaired by

P&CSD was charged with the development of a transportation fuel quality

roadmap to enhance the overall gasoline and diesel qualities to be environmen-

tally friendly.

the Green House Gases (GHG) – the main cause of climatechange. Saudi Aramco believes that the best way tocombat climate change is to look forward and actproactively. So far, Saudi Aramco has already takenserious steps to improve the environmental situation inthe Kingdom by establishing an Environmental MasterPlan that addresses all sources of contamination to the air,earth, and water. This master plan was endorsed by theSaudi Aramco board in 2001.

Figure 1 Gasoline Quality Roadmap Figure 2 Diesel Quality Roadmap


So far, Saudi Aramco has

already taken serious steps to

improve the environmental

situation in the Kingdom by

establishing an Environmental

Master Plan that addresses all

sources of contamination to the

air, earth, and water.

The primary objective of the master plan is to bring allSaudi Aramco facilities into compliance with thegovernment environmental regulations. It is also in linewith the company’s strategic initiatives to protect theenvironment and ultimately improve public health.

In addition and due to high sulfur levels in transportationdiesel, which eventually contributes to high SO2 emissions,the company has decided to include transportation dieselfuel into the master plan with the idea of addressingother fuels and air pollutants in the future. As a result,the master plan has recommended to lower sulfur intransportation diesel from 10,000 ppm to 500 ppmmitigating SO2 emissions from diesel engines.

Future Environmental Challengesto KSASince future challenges are always their ahead of us,Saudi Aramco has taken proactive measures byestablishing the fuel quality roadmap (Figures 1 & 2) thatwill ensure compliance to the government environmentalregulations at all times.

The fuel quality roadmap, which was recently

approved by the company board, has provided an

update to the existing environmental master plan,

bearing in mind the following future challenges:

• The kingdom has high urbanization level,

meaning that people tend to move to bigger cities

which ultimately cause high population and traffic

densities, especially in Riyadh, Jiddah, Makkah,

and Dammam.

• Since 1998 the number of registered vehicles has

increased by 45%.


Impact of Fuel Quality on VehiclePerformanceThere is without doubt global recognition that climatechange abatement and the drive toward lesser GHG canonly be achieved if vehicle manufacturers, refiners andlegislation work together. Since fuels and engines aretechnically linked with each other, the improvement ingasoline and diesel fuels quality will permit the adoptionof up-to-date low emission engines in the kingdom asopposed to the currently available. It is important tomention at this point in time that vehicle manufacturershave been supplying high emission vehicles to thekingdom in the past and they continue to do so at thepresent time. This is because their up to date enginecomponents are very sensitive to high sulfur fuels, whichwill cause it to be in-effective in a short while. Forexample, NOx and PM pollutants require special emissioncontrol systems to be embedded into the vehicles to trapand convert those pollutants into friendly gases. Forthose systems to operate efficiently (Figure 3), sulfur inboth gasoline and diesel fuels need to be further reducedfrom 500 ppm to 50 as an intermediate step andultimately to 10 ppm. At 10 ppm the emission controlsystems will give the utmost optimum performance thatwill drastically mitigate the NO2/PM emissions to the least.

Therefore, it is clear that reduction of NO2 and PMemissions are solely dependent on low emission enginetechnology. To introduce those low emission engines tothe kingdom’s fleet, it requires around 18 years to havefull replacement of our high emission vehicle fleet. As aresult, the actual realization of NO2 and PM emissionsreduction will take more time as compared with the otherpollutants.

Figure 3 Sophisticated Emission Control Systems


As a result, the master plan has

recommended to lower sulfur

in transportation diesel from

10,000 ppm to 500 ppm

mitigating SO2 emissions from

diesel engines.


UpdatesThe transportation fuel quality roadmap was presentedto the Management Committee on June 5, 2007. andsuccessfully acquired the MC‘s endorsement, to beinjected into the environmental master plan. In addition,several roadmap parameters were already implementedsuch as 800 ppm sulfur diesel (in major cities) and 5000ppm sulfur diesel (country wide) as compared to 10,000ppm sulfur diesel, updating MTBE specification to 15 vol.% as opposed to 10 vol. %, etc.

The required capital investment program associated withimplementing the long term strategy of the roadmap hasrecently been approved by the company board to beincluded in the 2009 – 2013 business plan cycle.

Fuels TechnologyIn line with Engineering Services knowledge sharingstrategy and to promote the understanding of the everchanging dynamics of vehicles technology and its relationwith fuel quality, P&CSD conducts regular workshops forSaudi Aramco executives and scientists.

In 2006, P&CSD sponsored a full-day manager’s workshoptitled “Importance of Fuel Quality & Effect on VehiclePerformance” on December 2nd, 2006. This workshopwas designed for relevant department managers whodirectly deal with fuels production, distribution, andspecifications. The primary objective was to raise theirawareness to the global trend towards producing cleanfuels and to underscore the interaction between engineand fuel technologies.

For this year, it is planned to conduct two workshops forscientists during December 9–10, 2007, and for executivesduring December 11, 2007. The objective of this year’sworkshops is to underscore, at a strategic level, the inter-relation between stringent fuel specifications, engineperformance, environment protection and thesustainability of oil market. Several other concepts will beaddressed, as well as the future of Dieselization and theKingdom’s environment, as a result of the recentlyapproved Fuel Quality Roadmap.

AcknowledgmentP&CSD would like to thank all the multidepartmentalmembers who participated in the development of theFuel Quality Roadmap for their great efforts andcontinuous support. Their time, dedication, andcontribution towards the completion of the roadmapadded great value.

Walid A. Al-Naeem is the Supervisor of Distillation andTreating Unit of P&CSD. He is also the Chairman of SaudiAramco Products Specifications Committee which is com-posed of cross functional members from various departmentssuch as FPD, EPD, R&DC, OSPAS, Distribution, RTSD, Sales andMarketing, and Domestic Refineries. This committee ischarged to look after various issues related to Saudi AramcoProducts and Fuels Specifications. Walid holds a MasterDegree in Chemical Engineering from KFUPM since 2003.Walid is a member in several local and international techni-cal societies and very active in IK / OOK events as chairman,speaker, and as a delegate.


On the other hand, the required

capital investment program

associated with implementing

the long term strategy of the

roadmap has been recently

approved by the company

board to be injected into the

2009 – 2013 business plan cycle.

Today, the world’s policy

makers and business leaders

are increasingly in agreement

that climate change is occurring

and it has to be addressed.

A Patent on Hydrogen Purification OptimizationSystem is Granted

Ibrahim M. Al-Babtain is a Refining Specialist in theDownstream Process Engineering Division of Saudi Aramco.Ibrahim has 18 years of experience in refining business.Joined P&CSD and participated with FPD and NBD as atechnical member in the development of major refiningprojects and evaluation of several technologies.

Author: Ibrahim M. Al-Babtain

This patent relates to the recovery of hydrogen from gas mixtures and, more

particularly, to a method for obtaining increased hydrogen recovery from oil

refineries and petrochemical or natural gas operations by combining a steam

reformer hydrogen product stream with an off gas stream and utilizing a combined

stream as a feed to a single Pressures Swing Adsorption (PSA) unit.

This idea was generated during the initial start up of anew refinery that includes multiple PSA units utilized totreat different feed streams of CCR off gas and refineryoff gas. One of these streams exceeded the capacity of therelated PSA unit and this portion of the excess gas is noteffectively utilized and typically sent to the flare or fuelgas system in the refinery. Another disadvantage is thatone of the PSA units is operating at high feed capacitywhich can increase the probability of damaging theadsorbent material within the PSA unit and carryingimpurities between the adsorbent layers. Also, flaring thisportion of excess gas requires compensation of sameflared quantity from another feed stream that feeds theother PSA unit.

Prior to development of this invention, there has been nosingle method of hydrogen recovery in refineryoperations in which some or all of the feed streams fromseparate PSA units were combined and utilized as feed fora single PSA unit, and in which some or all of a steamreformer product stream and a refinery offgas streambeing used as feed streams for separate PSA units werecombined and utilized as feed for a single PSA unit. Byapplying this invention in the refinery, the total hydrogenrecovery was increased in the refinery by effectivelyutilizing the excess gases that were flared, the load on thesteam reformer was reduced by lowering reformer feedrate, the refinery fuel gas consumption was reduced inthe steam reformer furnace, and the hydrocarboncontent and heating value of the tail gas, from the PSAunit fed by the steam reformer product stream, wasenriched.

The full utility patent application for this invention wasfiled at the United States Patent & Trademark office(USPTO) on July 2003 and the patent was granted underUS Patent # US 7,252,702 dated August 7, 2007.

With regard to implementing this invention, Yanbu‘Export Refinery Project’s director; Mohammad S. Al-Subhi

has provided his support and encouragement to considerimplementing this patent in the project if applicable assignificant capital savings could potentially be realized.The sketches below show the system before and after themodification.

Figure 1 System before the modification

Figure 2 System after the modification





Application of Flare Gas Recovery Systems inSaudi Aramco facilities

“Protecting the Environment,” “Managing andProtecting Resources,” and “Improving Health & Safety”are all part of our Business Line Strategies to meet theCorporate Imperatives. Installing a Flare gas recovery sys-tem (FGRS) at the tail end of a gas plant or a refinery willachieve all the above strategies, plus recover fuel gasworth $2/MMBtu. The Flaring Minimization Roadmap asendorsed by the Management Committee in June 2006,recommended installing flare gas recovery units in com-pany facilities where the normal daily flare gas rateexceeds 1-2 MMSCFD, after exhausting all possible flaringminimization efforts.

Why Flare Gas Recovery?The main drivers for a FGRS project are;

• It’s a proven technology

• It eliminates daily flaring, except for the pilots, thusproviding intangible benefits from reduced emis-sions of CO2 (green house gas), SOX, NOX, & VOCs.

The emissions of sulfur dioxide, ozone precursors

and particulates have a significant environmental

and health impact.

• It provides an economic incentive in returning the

recovered flared gas to the value chain, thus saving

on plant fuel gas.

• FGRS improves the reliability of the main flare tip.

This is an important consideration for the larger

diameter flares that are prone to damage from oper-

ation at the low daily flaring rates. With FGRS, the

main flare is in stand-by mode, which improves its

reliability and life, and minimizes the recurring cost

of flare tip replacement

• The project has a potential for emission trading and

CO2 credits, thus generating additional revenue.

• FRGS reinforces Saudi Aramco’s (& the Kingdom’s)

positive image as a responsible corporate citizen.

Figure 1 FGRS concept

Authors: Ra’ed Husseini, Prasad Pantula

The corporate Flaring Task Team led by P&CSD developed the Flaring Minimization

Roadmap that was endorsed by the Management committee in June 2006, The

roadmap recommended installing flare gas recovery (FGRS) units in company

locations where the normal daily flare gas exceeds 1-2 MMSCFD. This article

presents the concepts of FGRS and its application in Saudi Aramco.

Recovered Gas to Process

Existing FlaresHP/ACID or INLET

Flare Gas

Knockout Drum

New

StagingDevice

FGRS6 MMSCFD

N2 Purge

13



FGRS ComponentsA flare gas recovery installation for an existing plant willconsist of four main components: 1. A compression based package (FGRS) to recover the

flare gases for re-use in the existing processing facili-ties

2. Staging devices to safely allow diverting the routinedaily flared gases to the FGRS package but not theemergency or abnormal relief loads. Figure 1 illus-trates the integration of the FGRS into the flare sys-tem.

3. A nitrogen generation package to supplement exist-ing nitrogen generation capacity. Nitrogen will beused as purge gas, downstream of the staging device.

4. Control system within the package and interface withthe plant DCS

As shown in Figure 1, the Flare gas recovery unit ties intothe flare gas header between the knockout drum and thestaging device, and pulls flare gas from the header when-

ever flow is detected. Basically, the staging devices enablesafe operation of the entire system through sealing theelevated flares and provide backpressure in the flareheader, allowing the flare gases to be routed to the FGRS.

Process Design of FGRS packageAs shown above, the FGRS is a compression based pack-age designed to recover the flare gases for reuse in theexisting processing facilities. The system configuration isdependent on the final destination of the recovered gasand the type of compression equipment selected.

Destination of recovered gas: Some of the potential destinations for the recovered gascould be;

• Plant Fuel Gas header. This requires compressionfacilities to compress the flare gases from nearatmospheric pressure (3.5 psig max.) to approximately100-120 psig.

• Plant inlet Gas header. This destination is typically thesuction of the LP compressors in the GOSPs (1ñ50 psig)or the Inlet slug catchers in the gas plants (230 psig),which also requires compression facilities to compressthe flare gases to the required pressure.

Type of Compression equipmentThe choice of compression equipment will influencegreatly the configuration of FGRS system. A detailedsurvey of existing technologies revealed that the

Figure 3Typical Screw compressor packageoffered by Man-Turbo

Figure 2 Vendor offered package for FGRS with LRCs (courtesy: Envirocomb ltd)

The Flaring Minimization

Roadmap as endorsed by the

Management Committee in

June 2006, recommended

installing flare gas recovery

units in company facilities

where the normal daily flare

gas rate exceeds 1-2 MMSCFD,

after exhausting all possible

flaring minimization efforts.


exceeds the design capacity of the FGRS. • Pressure control, low pressure alarms, and ESD systems

should be provided at the inlet of the package toensure that positive pressure in the flare headers isalways maintained.

• The staging control valve/seal drum should bedesigned to open to existing flare stacks when eachcorresponding flare header flow exceeds the designcapacity of the FGRS.

Nitrogen purgeTo ensure positive pressure in the flare headers while theFGRS is in use, the flare headers will be continuouslypurged with nitrogen at a point downstream of thestaging devices or the water seal drum. As a backup to thenitrogen purge, fuel gas from the existing fuel gas purgeheader can be provided, with automatic controls.

Impact on the existing flare systemThe staging device seals the existing flare and imposes apositive back pressure on the flare gas header. This allowsrouting the flare gas to FGRS while maintaining a positiveflare gas header pressure, which is important with regardto the safety of the flare headers. Generally the maximumbackpressure allowed will have no impact on the existingPZVs connected to the flare header; however the actualimpact should be checked with flare simulation modelsduring the detailed engineering stage.

ConclusionsFGRS is a widely proven technology, though it has notbeen applied in Saudi Aramco. In future, all potential siteswill be considered for a detailed evaluation for itsapplication. Currently a DBSP is under development forinstalling a 6 MMSCFD FGRS units at ShGP & UGP . Otherpotential sites being evaluated are Safaniya GOSP1 andRiyadh Refinery. Hawiyah NGL Recovery, KhuraisDevelopment and potentially Khursaniyah are providingtie-ins for future units.

compressor types widely used for FGRS application are:

• Liquid ring compressor (LRC) with a variety of servicefluids, e.g., water, DGA, diesel, etc.

• Multistaged screw compressors (MSSC)The major advantages of the above compressors typesare as follows;

• Can handle a wide range of gases with varyingmolecular weights with no effect on theirperformance

• Can handle flow from zero to full capacity with arobust recycle system.

• Can tolerate liquid in the feed better than any othertype of compressors.

Typical vendor offered packages are illustrated in Figures2 & 3. The flare gas stream can be compressed in a LRCbased compression system to 100-110 psig with water as aservice liquid in a closed loop. A heat exchanger to coolthe circulating water and a three phase separator toremove oil and water are part of the package.Alternately, a screw compressor package may be utilized.

Design of staging deviceThe flare gas stream is intercepted at a point downstreamof the corresponding Flare Knockout drums by a stagingdevice. The staging device is set to divert the routineflaring rate of flared gas to the FGRS or to the elevatedflare if the rate exceeds the capacity of FGRS. The stagingdevices required to seal the elevated flare can be a waterseal drum or a Buckling Pin/fast acting control valvearrangement, similar to what is currently used at BGP,HGP, HdGP, and proposed for the Hawiyah NGL project.

Control SystemThe control system within the FGRS package and DCSinterface should be part of the FGRS process detaileddesign. The FGRS Process design vendors can provide thecontrol system design and interface to the DCS withoutcompromising process safety. The following are somerecommended features that should be part of a FGRSpackage; • The FGRS package should be isolated and safely shut-

down or put in recycle mode automatically when thestaging device opens, in the event the flaring rate

Prasad Pantula is with F&RSU /DPED since 2002. He has 25years of experience in upstream crude oil processing,petroleum refineries and process plant design.

Ra’ed Husseini is a Senior Engineering Consultant withP&CSD. He has over 23 years of Aramco experience in gasprocessing, refining and in upstream.


The system configuration is dependent

on the final destination of the

recovered gas and the type of

compression equipment selected.

the use of MTC. These are:2. Control of the optimum

regenerator temperature. 3. Adjustment of the feed

temperature up to itsbubble point to achievebetter atomization andfaster vaporization.

4. The heat absorbed with therecycle quench is recoveredas steam production,preheating, or reboiling inthe fractionation section ofthe FCCU.

Study ConclusionThe study evaluates the implementation and potentialapplication of MTC at JRD/FCCU by FCC Kinetic Modelsimulation model. The annual revenue incremental fromapplying this technology is significant. P&CSDrecommends consideration of the following future workif JR plans to implement the MTC technology:

Consider MTC technology for increasing the unitconversion and production of more gasoline yield.

Utilize of the FCC Aspen Kinetic Model to evaluate severalscenarios at different feedstock conditions.The author acknowledges the support from Graham Jones, AhmadAl-Othman from Pipeline & Simulation unit, Christopher Dean,Abdulaziz Al-Ghamdi and Adel Bawizer for finishing the ESA withJRD on time.


JRD/FCCU MTC Technology Evaluation By FCCAspen Kinetic Model

The evaluation study will identify for JR major impacts ofthe implementation of this technology by focusing in thefollowing area: unit conversion, gasoline sulfur content,Rx velocity, vapor line velocity and overhead coolingcapacity after recycling all LCO stream. P&CSD/DPED/CCUhas signed with JR an Engineering Service Agreement(ESA) to evaluate this technology by utilizing FCC AspenKinetic Models.

Proposed TechnologyThe MTC technology allows for independent temperaturecontrol of the catalyst cracking zone that results indecreasing yields of less desirable products (coke and gas).MTC is performed by injecting a recycle quench stream ofeither cracked FCC naphtha or light cycle oil, further upthe reactor riser downstream of the combined feedinjection point (See Figure 1)

This recycle quench stream results in separating thereactor riser into two separate reaction zones.

• The first zone, (Zone 1), between the fresh feedinjection point and the recycle quench streaminjection point, is characterized by high temperature,high catalyst to oil ratio and very short contact time ofoil and catalyst.

• The second zone, (Zone 2), between the recyclequench stream injection point and the risertermination into the reactor vessel, is where reactionsoccur under more conventional and milder catalyticcracking conditions.

The primary objectives of the MTC system are:1. To provide independent control of the catalyst and oil mix

temperature in Zone 1.

This recycle quench is a heat sink that behaves similarly to a steamcooler or a catalyst cooler in the regenerator side of the FCCreaction section. By behaving as a cooler the regenerated catalysttemperature can somewhat be controlled during the catalystregeneration. Usually the minimum regenerated catalysttemperature is the one that results with adequate catalystregeneration of coke. The cooler catalyst temperature causeshigher catalyst circulation rates for meeting the heat requirementsfor the cracking reactions and maintaining reactor outlettemperature. Additionally, there are also secondary objectives from

Authors: Saeed Al-Alloush, Sidney Anderson, Talal Al- Ashwal

The purpose of this study is to determine the feasibility of installing the Mix

Temperature Control (MTC) technology from Stone & Webster/IFP New Technology

to improve Jeddah Refinery profitability by increasing conversions of gasoline and

LPG on the Fluid Catalytic Cracking Unit (FCCU).

Saeed S. Al-Alloush is a senior process engineer in theDownstream Process Engineering Division, Process & ControlSystems Dept. (P&CSD). He has 15 years of experience withSaudi Aramco in refining area and mainly in Fluid CatalyticCracking area . He graduated with Master Degree of Sciencein Engineering from University of Tulsa (TU), USA. He is amember in American Institute of Chemical Engineering(AICHE) since 1997.

Sidney V. Anderson is an Engineer II in Saudi Aramco’s JiddahRefinery Operation Engineering Unit. He has over 38 years ofprocess engineering and refinery management experienceand has previously served on the NPRA Q&A panel. He hasalso written or co-authored several other papers related toFCCU operations.


Fig. 1 Mix Temperature Control atFCCU Feed Riser Section


P&CSD Downstream Process Engineering has promptlyextended troubleshooting support to Yanbu‘ RefineryEngineering and recommended a course of action to putthe unit in a normal mode of operation. The ContinuousCatalyst Regeneration (CCR) section of Yanbu‘ Refinery(YR) CCR Platformer Plant experienced successive catalystblowouts leading to the regeneration section shutdown.This caused the Platformer section to operate at reducedfeed rate and severity. Prolonged shutdown of thecatalyst regeneration section would have led to theshutdown of the Platformer Plant and the consequence oflosing the gasoline production.

Introduction The Yanbu‘ Refinery Platformer unit was revamped inJune 2006 from a fixed bed unit to a Continuous CatalystRegeneration Unit. Coked spent catalyst from thePlatforming reactors is continuously sent to the CCRRegeneration Tower where the coke is burnt off and the

spent catalyst is regenerated in four steps: 1) CokeBurning; 2) Oxychlorination – for dispersing the catalystmetals and adjusting the catalyst chloride content; 3)Catalyst Drying; 4) Reduction – for changing the catalystmetals to the reduced state. Finally, the regeneratedcatalyst is circulated back to the first Platforming reactor.Over a period of time catalyst fines plugs the Regeneratorscreen. The CCR has to be shutdown and the screenremoved for cleaning every 12 months.

Incident Background Since the first startup in June 2006, the CCR RegenerationTower has been operating with a partially plugged screenas a result of catalyst fines generated in the system fromthe containment loss in the Platformer reactors. This haseffectively reduced the Regeneration gas flow withoutaffecting the CCR operability. It was recommended by thelicensor to clean the screen at the earliest opportunity.The CCR was shutdown for a period of 5 days to carry out

Troubleshooting YR Cyclemax RegeneratorCatalyst Blow out

Figure 1 DCS Pressure Trends

Authors: Rabea M. Al-Saggaf, Hamzah Z. Abuduraihem, Neelay Bhattacharya, Sajeesh Padmanabhan

P&CSD/DPED/CCU assisted Yanbu‘ Refinery Engineering in resolving the recent CCR

Platformer regeneration catalyst pinning and blow out problem that resulted from

the over-design of the regeneration gas blower by installing a restriction orifice in

the Regeneration gas blower suction line.



Licenser Normal ShiftedTI Specified Profile Profile

Range

TI -1 479-510˚C 380˚C 250˚C

TI -2 493-593˚C 563˚C 465˚C

TI -3 493-593˚C 557˚C 475˚C

TI -4 493-560˚C 503˚C 511˚C

TI -5 491-504o˚C 492˚C 543˚C

TI -6 491-504˚C 487˚C 479˚C

TI -7 491-504˚C 485˚C 472˚C

TI -8 479-499˚C 485˚C 465˚C

the cleaning of the regeneration tower screen. The unitwas restarted in black burn mode. The startup was normaland the regeneration tower temperature profile had itspeak at the second TI in the Burn Zone. The operation ofthe regenerator for the next 36 hours was absolutelynormal with regenerated catalyst carbon at 0.095 wt%and spent catalyst carbon at 4.3 wt%.

On Tuesday, January 23, a blow out occurred between thedisengaging hopper and the regeneration tower whichcaused the disengaging hopper level to drop from 52 %to 47 %. The Disengaging pressure dropped and theRegeneration Tower pressure increased momentarily.Figure 1 below shows the pressure fluctuation and leveldrop at the time the blow out occurred.

Due to the blowout, a lot of fines and chips weregenerated that plugged the Regenerator screen. A shift inburn zone temperature profile has being experienced andthe peak temperatures shifted to fifth TI which is at thebottom of the burn zone (refer to Table 1).

Maintaining a proper burn profile in this section isextremely important for safe operation of the unit. If theburn profile shifts down, un-regenerated catalyst willenter the chlorination zone potentially causing catalyst toagglomerate and damage the Regenerator internals.

Intensive discussions were held between Refineryengineers and licensor experts on this subject and it wasconcluded that it is very difficult to pin-point the rootcause of the blowout. An attempt was made as suggestedby licensor to stop the regeneration blower and carry outcold circulation of the catalyst in order to clear the screen.Accordingly the regeneration tower was cooled as per

procedure at 50˚C/Hr. When the blower was switched tolow speed at 350˚C a blowout was again observed. Asimilar phenomenon was observed when the blower wasswitched from low speed to high speed during the reheat.There was no improvement in the unit performance.Therefore, the regeneration section was again shutdownas a result of repetitive blow out occurring between thedisengaging hopper and the regeneration tower. The CCRPlatformer throughput was lowered from the design of40 to 30 MBD and 95.0 operating severity to control cokelay down.

Analysis & FindingsIt is very unusual for a blowout to take place in a CCRbecause it is normally catalyst full. During normaloperation the catalyst flows down due to gravity. TheDisengaging Hopper operates at approximately 9kg/cm2(g) and the Regeneration Tower operates atapproximately 2.5 Kg/cm2(g). This huge pressuredifferential is taken by the catalyst in the long transferpipes between the Disengaging Hopper and theRegeneration Tower. If due to any reason a void is createdin the Regeneration Tower, the huge differential pressurewill force the catalyst down, causing a pressurefluctuation that generates a lot of fines and dust. Thefines will block the Regenerator screen, causing thetemperature profile to slip down.

P&CSD analyzed the problem on thefollowing lines:

1. One probable cause could be something blocking thecatalyst transfer pipe. But this would be a one timeoccurrence that would get automatically cleared afterthe blowout. But since the blowout reoccurred it wasobvious that it was not due to plugging of thetransfer pipes.

2. The only difference between the two startups was thecondition of the screen. Since initial startup the unitwas operating with a plugged screen. The recentstartup was the first time with a clean screen.

3. The blowout was clearly related to the bloweroperation because the blowout had happened on twooccasions when the blower speed was switched.

Analysis of the previous operating data showed that theblower flow was 102 % of design even with a partiallyplugged screen. Once the screen was cleaned the flowincreased causing the catalyst to pin in the RegenerationTower. Since the Lock Hopper is removing catalyst, a voidwas created at some location in the Regeneration Tower.When the differential pressure between the Disengaging

Table 1: Regeneration Tower Normal and IncidentTemperature Profiles



Hopper and the Regeneration Tower was high enough, itforced the catalyst to fill the void creating a blowout. Thiswould also explain why the blowout occurred when theblower speed was changed. The first time when theblower was switched from high speed to low speed thecatalyst unpinned, causing an immediate blowout. Thesecond time the blower was switched from low speed tohigh speed caused the catalyst to pin. The blowout didnot occur immediately. During subsequent heat up thecatalyst slumped, creating a void below the pinned area,causing a blowout.

A conference call was initiated by YR Engineering andP&CSD with the Licenser on January 31, 2007. P&CSDconvinced the licensor that the blower could be a highlyprobable cause for the blowout and it was decided that:

1. The licensor would size a restriction orifice to reducethe Regeneration Gas flow by 15-20 % to avoidpinning. YR would keep it ready for installation in theRegeneration tower gas outlet line.

2. Conduct inspection of the disengaging hopper andregeneration tower screen.

3. If inspection did not reveal any obvious reason toexplain the blowouts, then install the restrictionorifice in the Regeneration gas outlet line and observethe unit performance on restart.

Field InspectionThe regeneration tower and the Disengaging Hopperwere open for inspection. While unloading the catalyst,the last few drums from the Disengaging Hoppercontained fresh catalyst. YR had added 12 drums of freshcatalyst to the Disengaging hopper during the recentreload. Since the catalyst had been circulated for 500cycles there should not have been any fresh catalystremaining in the Disengaging Hopper. This clearlyindicated that the catalyst was not moving as a result oflocalized catalyst pinning on the regeneration towerscreen. No clumps or debris were found between thedisengaging hopper and the regeneration tower. TheRegeneration screen was heavily plugged. There was nosign of integrity loss or severe damage to the screen.

P&CSD concluded that the root cause for this problem wasthe oversizing of the regeneration gas blower.

Recommendations P&CSD recommended installing a restriction orifice in theRegeneration gas blower suction line to reduce theRegeneration gas flow and increase the pinning margin.YR and Licenser supported P&CSD’s findings and decided

to install a restriction orifice in the regeneration gasoutlet line, to reduce the regeneration gas blower flow byapproximately 15%, and prevent catalyst pinning on theregeneration tower screen. Unit licensor designed arestriction orifice with a bore size of 340mm, which wasfabricated by YR and installed in the Regeneration gasoutlet line to reduce the flow by approximately 15%.

CCR Restart The regeneration section was restarted on Feb 6, 2007,after the installation of the restriction orifice. The startupwas smooth without any pressure fluctuations or signs ofblowout. The circulation rate was slowly increased to 95% of design and the oxygen concentration was slowlyreduced from 1.0 mole% to 0.9 mole%. Laboratory resultsshowed less than 0.07 wt% carbon, indicating completeregeneration. The temperature profile in theregeneration section was satisfactory, indicating noreduction in the unit capacity.

In conclusion, installation of the restriction orifice on theregeneration gas blower suction eliminated the pinningproblem from the over-design of the blower. Normal CCRPlatformer operation resumed.

Rabea M. Al-Saggaf is a process engineer working with SaudiAramco Yanbu‘ Refinery Department. He has 10 yearsexperience in refineries. Rabea holds a B.S degree in chemicalengineering from King Abdulaziz University, Jeddah 1996.He joined Saudi Aramco in 1996.

Neelay Bhattacharya is a process engineer working withSaudi Aramco Process and Control Systems Department. Hehas 17 years experience in Refineries and Petrochemicalplants. Neelay holds a B.E degree in Petroleum andPetrochemicals from Pune University, India 1990. He joinedSaudi Aramco in 2006.

Hamzah Z. Abuduraihem is a process engineer working withSaudi Aramco Process and Control Systems Department. Hehas 15 years experience in refinery operation and project.Hamzah holds a M.S degree in Chemical Engineering andPetroleum Refining from Colorado School of Mines, USA2001. He joined Saudi Aramco in 1992.

Sajeesh Padmanabhan is a chemical engineer and works withthe Operation Engineering & Automation Unit at Yanbu‘Refinery. He has 11 years of experience in Hydrotreating,Plaforming and Petrochemicals. He joined Saudi Aramco inJan 2005.



DHAHRAN — As company refineries look for newtechnologies and ways to revamp operations and bestpractices, more than 100 engineers, specialists andconsultants gathered on March 28 to discuss the latestcrude and vacuum distillation technologies.

Personnel came from Saudi Aramco domestic refineriesand central engineering services to join worldwideindustry experts on March 28 for the first DistillationWorkshop.

The event was conducted and organized by the Processand Control Systems Department (P&CSD) at the Researchand Development Technical Exchange Center under thetheme, “Distillation: Revamping, Troubleshooting,Technology and Energy Conservation.” The aim was tocreate a learning organization, a stated goal ofEngineering and Operations Services.

P&CSD Manager Saleh A. Al-Zaid highlighted theimportance of the distillation process in every plant andrefinery. He also concentrated on the importance ofP&CSD in supporting Saudi Aramco’s domestic refineries,especially given the rise in fuel demand.

“The importance of this workshop is derived from theimportance of crude and vacuum distillation processes,”Al-Zaid said. “Crude and vacuum units are the heart andthe main gate of every refinery in the world. Theirimportance is not negotiable.”

Representatives from two leading companies in crudedistillation process revamps and technologies, Koch-Glitchand Sulzer Chemtic, presented “Primary RefineryTreatment: Process and Technology.” That was followedby panel discussions on Crude Distillation(Atmospheric/Vacuum) and Crude Handling andDesalting, featuring panelists from Saudi Aramco, andSulzer and Koch-Glitsch.

The Sulzer representative delivered the secondtechnology presentation, “Maximize Distillate Recoveryby Means of Advanced Mass Components.” That wasfollowed by a panel discussion on energy conservation atcrude distillation units, moderated by Tariq A. Al-Zahraniand Khalid S. Al-Otaibi from P&CSD’s Distillation andTreating Unit.

“It was a great opportunity to exchange experienceswith engineers, specialists and consultants fromdifferent organizations within Saudi Aramco andworldwide industries,” said Mohammed S. Al-Ghamdi,Yanbu‘Refinery Operations Engineering and AutomationUnit supervisor, of the value of the workshop.

Walid A. Al-Naeem, supervisor of D&TU, concluded theworkshop by thanking the attendees for theirparticipation.

Distillation Workshop

Saleh A. Al-Zaid, manager of P&CSD left talks with Said Al-Zahrani &Mohammed Slamah during break time.

Distillation workshop attendees, organizers and panelists pose for a picture in R&DC Technical Exchange Center.



P&CSD Supports Local ProfessionalSocieties: AIChE-SASThe American Institute of Chemical Engineers (AIChE) – Saudi Arabian Section

(SAS) is a non-profit professional association. It has memberships from all major

companies of Saudi Arabia including SABIC, Saudi Aramco, KFUPM, SWCC, Royal

Commission, and many other private companies. One of the major activities is

the Monthly Technical Dinner Meeting of the members. The Meeting is

highlighted with presentation from a well-known expert/specialist on chemical

engineering-related subjects and major activities in the downstream industries.

Further information about the meeting or the society can be viewed by visiting

our web-site @: http://www.kfupm.edu.sa/sas-aiche.

Process & Control Systems Dept. (P&CSD) has sponsored April 8, 2007, Meeting

of AIChE-SAS in the Meridian Hotel, Khobar. The Guest Speaker was Mr. Khaled

Al-Faleh, Sr. VP, Industrial Relations of Saudi Arabian Oil Company (Saudi

Aramco). Mr. Al-Faleh discusses Saudi Aramco’s global and national business

challenges and the need to elevate IK educational outcomes to meet the

country’s rapid economic growth and international competition. In this regard,

he has addressed the state of the Kingdom’s educational system and its

competitiveness at an international level. In addition, three key Board Officers

from P&CSD are investing a lot of after-hours to make this chapter successful and

serve the chemical engineering society for the year 2007.

The Guest Speaker Mr.Khaled Al-Faleh, Sr. VP.Industrial Relations of SaudiArabian Oil Company (SaudiAramco) addressed hispresentation “EducationalOutcomes & Industry Needs:Saudi Aramco’s Perspective”during AIChE-SAS Aprilmonthly meeting sponsoredby P&CSD.

Mr. Abdulmohsen D. Al-Majnouni, AIChe-SAS Chairman, hand on the society plague

to Mr. Saleh Al-Zaid, P&CSD Manager, to thank him for his contribution.


Pipeline Simulation Interest Group (PSIG) that will takeplace in October this year in Canada.

The paper introduces new method of simulating a processvariable (PV) rate of change with respect to time (time

derivative d(PV)/dt), that is usually not readily available ordirectly calculated by some dynamic pipeline simulators.The method makes use of elementary concepts ofProportional-Integral-Derivative (PID) controllers alongwith commercial software packages of pipeline dynamicsimulators, like Stoner Pipeline Simulator (SPS). The paperdescribes the method and its application in the oil and gasindustry. One application is related to overpressureprotection of cross-country pipelines (Figure-1). Themethod can also be applied to the proper selection of acheck valve as an integral part of a pipeline system(Graph-1).

In pipelines process dynamic simulation packages, flow,pressure and temperature are the most commonly usedcalculated PVs. Flow, on the other hand, is the mostcommon PV rate of change of mass or volume with

22


Rate of Change Modeling

N. A. Al-Nasr and M.A. Al-Rasheed co-authored a jointpaper titled “A Method of Simulating Rate of Changewith Applications in Pipelines Protection and CheckValves Selection.” The paper has been accepted forpresentation and publication in the 2007 Conference of

Graph 1Pressure & Flow Profile of the SimulatedPipeline System

Figure 1 Schematic of water injection pipeline system


Authors: M. A. Al-Rasheed, Nazar A. Al-Nasr

A New Method is proposed to simulate rate of change of process variables. The

method can be appllied in the oil and gas industry such as in pipelines overpressure

protection and valve selection.

V.SRV

NODE1

NODE2

B.SRVNODE3

H.SRVE.SRV NODE4

E.UWSS1.SUCT

N.UWSS1.SUCT

UPUMP1 NODE5

UPUMP2

UBLOCK1

N.UWSS1.DISCH

NODE6

NODE8

UBLOCK2

B.UWHW.IN T.UWSS1B.HCWIPNODE7

T.UWSS1A.HCWIP

LOOP

B.UWHW.OUT

HWELLS NHCWIP001

respect to time. Fluid velocity (V) in a pipeline is another

example of a PV rate of change of the fluid traveled-

distance with respect to time, which is usually calculated

from flow rate based on physical properties of fluid (e.g.

density and viscosity) and pipe size and material. The

pressure rate of change (dP/dt) such as pressure rate of

rise (PRR), or velocity rate of change (dV/dt = a), that is,

acceleration or deceleration are not standard calculatedoutputs in pipelines hydraulics and surge analysissoftware programs.

A PV rate of change like dP/dt is very useful in surgeanalysis to simulate rate-of-rise types of surge reliefvalves. Also, knowing a PV rate of change like dV/dt froma transient analysis simulation, helps identifying the

23


Graph 2PRR Controller Output (Red) & FSP ControllerOutput (Black) After Surge

Graph 3Response of SRV (Relieved Flow in Blue) to PRR& FSP Controllers After Surge

Graph 4Dimensional Dynamic Performance Curve (DPC)of Various Check Valves Graph 5

Non-dimensional Dynamic PerformanceCurve (DPC) of Various Check Valves



Nazar A. Al-Nasr: Holds a PhD of Mathematics since 1981from Clarkson University, NY, USA. An assistant professor ofmathematics at KFUP, for two years. Published severalpapers on mathematical applications to multi-variablecontrol systems. Joined Saudi Aramco in 1983. Has 12 yearsof experience in operator training simulators (OTS).

Developed in-house real-time custom models for OTS in theNorthern Area Producing. Currently an engineering specialistin pipeline hydraulics and surge analysis simulation.

M. A. Al-Rasheed: A Pipeline Hydraulics & Surge Analysisengineer in the Upstream Process Engineering Division. Hasmore than 15 years experience in the oil industry. Holds adegree in chemical engineering from King Fahd Universityof Petroleum & Minerals in Dhahran. A member of thePipeline Simulation Interest Group (PSIG) and the American

Association of Chemical Engineering (AICHE).

suitable check valve for a specific system and application.

There are also situations where PV rate of change isneeded to be observed almost continuously and displayedbefore an operator in the form of “rate of change”alarms, where abnormal variation of PV data with respectto time, such as sudden increase or decrease of pressurecan trigger rate of change alarms. While PV data may notbe high or low enough to trigger normal high or lowalarms, rapid fluctuation in PV value, in the from of rateof change with respect to time, can indicate abnormaloperating conditions. Such rate of change alarms wouldthen alert the operator to respond ahead of time to theobserved abnormal situation and take a corrective actionbefore unacceptable operating conditions can occur.These kinds of alarms can be simulated by applying theproposed method.

Though, the derivative action in a PID controller can causeamplification of any noise in the error signal, theproposed method of derivative-only controller can beapplied in simulation with the absence of any source ofnoise.

The proposed method is detailed with two illustrativeapplication examples in the PSIG paper.

Graph 6Fluid Velocity Before & After Closure of theDownstream Valve

Graph 7Response of SRV (Relieved Flow in Blue)to PRR & FSP Controllers After Surge


A PV rate of change like dP/dt is

very useful in surge analysis to

simulate rate-of-rise types of

surge relief valves.

Though, the derivative action in

a PID controller can cause

amplification of any noise in

the error signal, the proposed

method of derivative-only

controller can be applied in

simulation with the absence of

any source of noise.


TORR Technology for Produced Water Treatment

As assets mature, and produced water volumes increase,producing facilities face major problems in dealing withthe resultant process issues. On the other side of theequation, increasingly stringent discharge specifications,limit the disposal options open to these facilities; i.e.,current oil-in-water content between 50-100 mg/l withfuture reductions to less than 50 mg/l.

All these factors mean that produced water is no longer asimple waste stream. Equally, the complexity of theproblem is such that no single item of equipment isenough to mitigate the problem, and a truly integratedapproach is therefore needed to address all aspects of theprocess.

This challenge is visible in NAOO as capital projects havealready been put in place, to expand and improve thepresent water handling facilities, for the GOSPs tooperate at the maximum sustained rates/capacities (MSC).

Oil-In-Water Separation Theory:The performance of any given separation technique will

Technology approach towards challenges faced by the significant increase of pro-

duced water from the oil fields “Optimize Operations for Improved Performance”

depend entirely on the condition of the oil-watermixture. Present techniques for the separation of oil fromwater are based on their difference of density.Stoke’s Law states that rising velocity (Vr) is a function ofthe square of the oil droplets’ diameter as shown in thebelow equation: Vr α d^2 (ρw – ρo) / µWhere Vρ = rise velocity of oil dropletρw = density of water, ρo = density of oild = oil droplet diameter, µ = viscosity of water

From Stoke’s Law, it can be seen that droplet size has thelargest impact on the rising velocity rate of oil droplets inwater. Consequently, the bigger the droplet size, the lesstime it takes for the droplet to rise to a collection surfaceand thus easier to treat the water. The oil in the producedwater can be present as free-oil, and/or dispersed, and/ordissolved states in different proportions.

Free-oil is defined as an oil droplet of 150 microns, whichwill float immediately to the surface due to its large sizeand high rising velocity. An emulsion is defined as oilwhich is dispersed in the water in a stable fashion due toits small diameter and its low rising velocity.

Author: Salah M. Al-BinHaji

Figure 1 Technology Oil-In-Water Separation Process



Salah M. Al-BinHaji is a process engineer with OilProduction Unit /UPED. He has seven years of experiencewith Saudi Aramco. He worked as a plant engineer, seniorengineer and safety/Environmental/Health engineer inNorth Ghawar Producing Department. Currently he is on aone year assignment with P&CSD.

The Challenge of Removing Small Oil-In-Water Droplet:Even under favorable conditions, oil droplets smaller thanabout 30 mm in water are known to be quite difficult toseparate (From Literature). Oily water with small dropletsless than 30 mm are even more difficult to separate.

Therefore, it is important to fully understand thecharacteristics of the produced water. The sizedistribution curve for the dispersed oil in water must bemeasured to effectively address the issues and meet andexceed the set discharge targets.

TORR Technology (Newly introducedtechnology for produced water treatment):As part of P&CSD efforts in exploring technologies tooptimize operations for improved performance, newproduced water treatment technology (TORR™) is beinginvestigated for application.

The TORR™ (Total Oil Remediation and Recovery) Systemwas developed by EARTH (Canada) Corporation.

This technology is based on the filtration, coalescence,and gravity separation process. These three principles arecombined together into a single process resulting in aself-cleaning oily water filtration system. To achieve that,the RPA® (Reusable Petroleum Absorbent), ahydrophobic absorbent developed and patented byEARTH (Canada) Corporation, is used as a filtration/coalescing medium. The RPA has the followingcharacteristics:

• Absorption of very fine emulsions down to 2 microns as

a result of being highly oleophillic.

• Capacity to continue absorbing the fine emulsions even

when it’s fully saturated with oil, while desorbing the

coalesced oil as free-floating oil.

The two previously mentioned characteristics of RPAallows for an efficient process (removal of oil emulsionsdown to 2 microns) and also a self-cleaning system(continuous oil separation and recovery) with lowoperations and maintenance.

The technology offers several potential benefits asfollows:

• Separates and recovers non-soluble dispersedhydrocarbons in water with approximately 2 microns indiameter and larger.

• Reduce the hydrocarbon content of non-solublehydrocarbons to below 10 PPM. The technology claims tohave the highest oil removal efficiency for oil-in-waterdroplets size even below 30 mm (between 15-30 mm).

• Accomplishes oil separation and recovery without theneed for chemicals or heat, thus operational costs areminimal.

• Energy requirements for pumping the oily water areminimal since the TORR™’ system’s pressure drop acrossthe process is low.

P&CSD has coordinated a technical meeting for the newtechnology in which representatives from SAOO, NAOO,EPD, FPD, and Aramco Service Company (ASC) attendedthe meeting.

P&CSD is in the discussion stage with the vendor andNAOO for conducting a trial test of this technology.

Figure 2 Technology Process Flow Diagram


The size distribution

curve for the

dispersed oil in water

must be measured to

effectively address the

issues and meet and

exceed the set

discharge targets.


27Process & Control Systems Department Issue No. 8 – Summer 2007

0

1000

2000

3000

0.6

0.8

1

1.20

20

40

60

80

100

120

ReImpReImp

ReImpReImp

ReL

ReL

ReL

ReL

0

1000

20003000

0.6

0.8

1

1.20

20

40

60

80

100

120

ReG

ReG

ReG

ReG

01000

20003000

0.6

0.8

1

1.20

50

100

150

200

250

01000

20003000

0.6

0.8

1

1.20

50

100

150

200

250


The basket impeller column is an alternative catalyticdistillation reactor design for systems that require aneffective catalytic liquid renewal and high rate oflocalized mixing to overcome severely limiting masstransfer resistances. The basket impeller consists of 4-blade wire mesh, distributed one per stage, that containssolid catalysts typically found in a stirred basket slurryreactor. The liquid contact with the catalyst is enhancedwith rotational speed of the basket impeller on a renewalbasis, allowing for slip velocities much higher than thoseachieved with a static catalytic distillation column. Theimpeller is located directly above a sieve plate in a columnwithout downcomers. The current configuration of thebasket impeller column, with dual flow action bubblerecirculation provided by the impeller, enhances the gasliquid contact that results in higher mass transfer rates.The objective of this study is to provide correlations of thebasket impeller column to better understand the systemand use them in future applications. Deriving processmodeling that characterizes such a configuration willmake the utilization of this system more widely applicablefor future experiments; this includes loading and floodingenvelopes. In addition, the hydrodynamics and gas toliquid mass transfer, over a range operating parameters,was determined. As the operating range lay in themiddle, it was found that the actual number of stages isequal to the calculated N model ”calculated number ofstages”. The phenomenon of mechanically assisted forcedweeping was thoroughly investigated by using pressure

Hydrodynamics and Gas-Liquid Mass Transfer Characteristics of a Multistage

Dual-flow Spinning Basket Impeller Catalytic Distillation Columndrop and liquid hold up of stage correlations. Thevolumetric mass transfer coefficient and interfacial areawere determined using the absorption chemical system ofcarbon dioxide in sodium hydroxide andcarbonate/bicarbonate buffer solutions. The resultingcorrelations were typical of those found in dual flowcolumns, with improvement obtained through agitation.

DiscussionLoading and flooding Envelope:It is clear from the above figure for the loading andflooding envelope that the non-linearity occurred fromsteep areas of change on the envelope surface. Thesewere represented using a power law type expression oneach surface. The loading envelope for this column with 7and 13 % Open Area plates over the ranges of superficialReynold numbers:

0 ≤ ReG ≤ 250.0.6 ≤ ReL ≤ 1.6,0 ≤ 1.6 ≤ 0 ≤ Ω ≤ 300

are obtained by:

ReG Loading = 8.875 * 10-0.2ReL-0.2210(5.108x10-0.5ReL+4.17)θ1.26

The ReG values obtained from this equation representsthe establishment of a froth structure in the presence ofthe operating basket impeller, which is typicallyillustrated by sustained large bubble formation.

The flooding envelope is similarly obtained over the samerange of operation for the basket impeller column for the7 and 13 % Open Area plates by:

ReG.Flooding = 6.406x10-0.2 ReL-0.17 10(6.08x10)-0.6 Re1+4

Those corresponding to this equation predict the onset

Basket Impeller Column: New ApproachAuthor: Salem Al-Qahtani

Figure 1 Experiment setup

Figure 2 Capacity Loading and flooding Envelope

Basket Impeller Column

T

P

PP

Cumulative Flow Meter

Gas Chromatograph TCD

Gas Feed Pre-Saturator

Gas Supply N2 and CO2

RTD Pressurized Fraction Collector

Liquid Phase Supply and Reciever

Variable SpeedPeristaltic pump



flooding where by the froth height has reached thestages highest point of 0.15 m. When comparing loadingto flooding, the loading is generally sensitive to allvariables, while flooding is particulary affected by ReL theimpeller Reynolds number and q the fractional plate openarea. The potentially significant interaction of these twovariables has been shown to strongly influence traycapacity. These equation define the applicable range ofall correlation subsequently reported.

Residence Time Distribution (RTD) The below figure shows a typicall RTD curves for thesystem, it reflects the type of behavior observed duringthe study:

As the basket impeller rotational speed Ω increases, the E-curves increase as well. This observed increase in variancewith Ω from 0 to 150 is caused by the higher axialdispersion within the column, and increased residence ofthe tracer within the packed basket. As the rotationalspeed Ω increased, the froth structure collapsed due tothe force of weeping that produced a return to plug flow.

Mass Transfer Gas-to-LiquidAs the surface area of mass transfer increases, the masstransfer will increase as well. This fact is iullstrated in thebelow figure for the two plates 7 and 13 % Open Area(OA). The 13 % plate has a higher operating range than 7% plate:

The 13 % OA plate has a higher throughput, whichprovides for a higher gas to liquid mass transfer. Previouswork with this configuration showed that the efficiencyof distillation column at mid range of operation for thesmall area plate is usually higher than large one. Thisresult is also true for the standard bubble column withoutinternals. The correlation for the effective mass transfercoefficient for liquid kLaL is as follows:

kLaL = b1Re2+b2Re1+b0

b1 = 145x10-09 – 1.36x10-10ReG–4.74x10-10ReL+1.28x10-07θ

b2 = 135x10-06 + 210x10-07ReG+234x10-05ReL–1.98x10-01θ

b0 = 244x10-02 + 9.36x10-01ReG+1.01x10-02ReL–1.21θ

Conclusion It is concluded in this study that the basket impellercolumn operating range becomes broader as the % OA ofthe plate increases, the larger the OA, the higher theoperating maximum and minimum. The broader range ofoperation will give flexibility on the column and allow thegas and liquid flow rate to vary. Therefore, thecontrollability of the basket column impeller withhigher % OA plate is easier than the low % OA one. Theefficiency with smaller plates is higher than the largerone. Moreover, it is revealed from the RTD experimentsthat at mid range of operation, the number of stages Nfor the basket impeller column become close to the actualnumber of stages. Operating at or close to loading andflooding envelopes result in partial bypass andrecirculation, resulings in a highly back-mixing column. Inthe gas to liquid mass transfer experiments, it revealedthat the mass transfer is typically of tray plate withstationary basket, with additional, enhancement of theimpeller to a certain maximum, before froth collapsedand force of weeping decreases the liquid. The masstransfer of the 13 % OA is higher than the 7 % plate. Ahigh area provides more gas to liquid contact. Thebehavior of dependent parameters is typically non-linearwith respect to rotational speed.

Salem Al-Qahtani is a Process Engineer withP&CSD/UPED/GPU. Salem’s main specialty is NGL recoveryand fractionation. He holds a Master of Engineering Sciencefrom the University of New South Wales, Sydney Australia.

Figure 3 Residence Time Distribution (RTD) Analysis

Figure 4 Mass Transfer Results

0.1

E-(t

)

00 20 40 60 80

0.09

0.08

0.07

0.06

0.05

0.04

0.03

0.02

0.01

t (min)

0 rpm

150 rpm

250 rpm


0.06

Ω

KLa

(s-1

)

0.05

0.04

0.03

0.02

0.01

00 100 200 300

(rpm)

13% ReG 170.7

7% ReG 51.2

7% ReG 43.9

13% ReG 139.0


Data Validation and ReconciliationA Crucial Technology for Processing Plants

This necessitates the need to validate plants’measurement data utilizing all available andpossible process data, exploiting the basiclaws of physics. After data validation,reconciliation is a method for extracting allinformation present in plant data to gain thegreatest economic value.

EPIs, as well as KPIs for critical equipment,provide the plants the means to monitor andimprove process performance, therebyreducing energy consumption.Understandably, instrument and equipmentmaintenance in a large organization such asSaudi Aramco can be a daunting andoverwhelming task resulting in severalmeasurements being inaccurate andsometimes invalid.

In 2004, Saudi Aramco evaluated the five leading data

validation and reconciliation (DVR) applications to

provide the needed measurement data validation. VALI

from Belsim s.a./NAIZAK Global Solutions was the

primary choice application for data validation &

reconciliation (DVR).

Saudi Aramco has since implemented a project pilot atRiyadh Refinery’s crude distillation unit as well as a plant-wide material balance model. In addition, a pilot at theShedgum Gas Plant liquid recovery unit provided plantEPIs and equipment KPIs for proactive and predictivemaintenance. The implementation of VALI-DVR revealedpotential opportunities for revenue enhancements aswell as insight for proactive predictive maintenance andincident avoidance. A good example is the heat transfercoefficient KPI, calculated for cleaned as well as new typesof tubes (see figure 1). One can clearly see the

The validity and accuracy of measurement data are crucial factors to successfully

exploit plants’ Key Performance Indicators (KPIs) and Energy Performance Indices

(EPIs). Measurement data are inherently plagued with varying degrees of

inaccuracies.

deterioration as well as the improvement in the heattransfer coefficients before and after tube cleaning andreplacement. This information is provided online at anydesired time interval allowing for condition-basedmaintenance as well as incident avoidance. Also, itprovides insight to equipment performance, revealing,for example, that the new tubes’ types have higher heattransfer coefficients than the old ones.

Saudi Aramco is proceeding to establish a corporatelicense agreement for faster implementation of theapplication across all its producing, gas processing and oilrefining facilities.

Dr. Amein Alsuezi is the Data Validation & Reconciliationteam leader within PCD of P&CSD. With more than 20 yearsof industrial experience, he has extensive knowledge insuccessfully leading and managing projects. Prior to joiningSaudi Aramco, he worked in the USA as independentconsultant for various companies.

Author: Amein Alsuezi

Figure 1 Heat Transfer Coefficients’ KPI for cleaned aswell as new type of tubes

Stabilizer Reboilers

0.00

50.00

100.00

150.00

200.00

250.00

300.00

350.00

400.00

450.00

7/1/06 7/3/06 7/5/06 7/7/06 7/9/067/11/06 7/13/06 7/15/06 7/17/06 7/19/06 7/21/06 7/23/06 7/25/06 7/27/06 7/29/06 7/31/06

8/2/06 8/4/06 8/6/06 8/8/068/10/06 8/12/06 8/14/06 8/16/06 8/18/06 8/20/06 8/22/06 8/24/06 8/26/06 8/28/06 8/30/06

9/1/06

Heat Transfer Coefficient

E-26AE-26B

Heat TransferDeterioration

Design Heat Transfer

Coefficient (HTC)

HTC higher than previousdesign value

Tubes

ReplacedDeteriorat

Tubes CleanedDeterior



Optimizing Projects with a Main Automation Contractor

Process Automation Systems (PAS) are used in most SaudiAramco industrial capital projects and hence havesignificant impact on the cost, quality and on streamoperation of Company plants and facilities. The MainAutomation Contractor (MAC) concept was created byindustry users in conjunction with process automationsuppliers to optimize PAS projects execution.

MAC is defined as a highly qualified, large projectsexperienced, and well resourced control systemscontractor assigned to engineer, supply/procure andmanage Process Automation Solutions and associatedinstrumentation for all project process areas and facilities.

As part of its strategic initiatives to support corporateperformance transformation, P&CSD has launched acomprehensive study of the MAC concept to assess itsapplicability and value to Saudi Aramco PAS projects. Ateam comprising of representatives from P&CSD, PMT,FPD, and PS&CD was formed to conduct the study, assessrisks and validate projected benefits.

BackgroundIt is well known in the industry that PAS expendituresrepresent about 3% - 5% of an overall project budget.Improper planning, design and implementation can drivethe cost of PAS by an additional 10%-25% of its value.Furthermore, PAS is the foundation for a plant operationwhich can result in 100% downtime if not properlydesigned and configured. Therefore, it is essential tofocus on PAS during the initial Project Proposal (PP) phaseto ensure that overall PAS design, scope and integrationrequirements are properly defined.

Traditional PAS projects proposal phase has beenexecuted by design contractors in the absence of ProcessControl Supplier (PCS). Similarly, during the detail designand construction phases, Lump-Sum Turn-Key (LSTK)contractors have typically performed the role of theautomation contractor while the scope of the PCSremained limited to implementing the design packages.This approach has resulted in numerous project executionproblems including:

• Unplanned scope changes

• Unplanned resources

Transform Corporate Performance is one of our Corporate Strategic Imperatives,

and Process Automation project execution is one of the processes that require

dynamic optimization to ensure quality and cost effectiveness.

• Design inconsistencies

• Poor interfaces between PMT, EPC, and subcontractors

• Inconsistent selection of equipment and materials

• High projects contingency

As a practice in the industry to overcome the problemsassociated with the tradition project execution approach,The MAC concept was created to address the followingbusiness drivers:

• Economics

• Accurate definition of PAS scope prior to projectdetailing

• Reduction in change orders

• Improvement is project schedule

• Better integration with third party equipment

Figure 1 shows that early involvement of MAC in theproject design can positively influence project cost whilelate involvement in a project could result in additionalcost expenditures, due to change orders andcontingencies.

Findings and BenefitsThe Team has concluded that the MAC concept is anindustry trend and widely used by major Oil & Gas usersas a strategic project execution tool. MAC has beenproven to reduce PA project costs by 10 – 15%, improveoverall Process Automation schedule, improve totalintegration quality, and reduce risks.

Definitive estimate & proposal at the early stage is critical for customer success

Abi

lity

to In

flue

nce

Cost

High

Concept Phase Planning Phase Implementation Phase Close-Out-Phase

Low

Cost Influence

Cost Expenditure

20% 40% 60% 80%

Figure 1 MAC impact on Project Cost

Author: Saleh Al-Qaffas



Highlighted benefits from vendor proposals/presentations, interviews and work sessions with industryusers, LSTK contractors, and SAPMT are the following:

• MAC involvement in each automation area willcontribute to consistency and higher quality ofprocedures and specification documentation

• MAC will contribute to higher quality integratedsystems from the field instrument to the board room

Early MAC involvement during FEED (Project Proposal)reduces project cost via reduced change orders, lowercontingency, and shortens development time. Estimatedproject cost avoidance is in the range of 10-15%.

MAC will improve overall automation schedule due toearly involvement in project proposal development.Typically, more than 5 months are saved in a projectschedule due to MAC early selection and basic designavailability. This concept would take automation systemout of the critical path during detail design andconstruction phases.

All system releases are managed by MAC to ensure latestversion upon project completion

Impacted Saudi Aramco StandardsIn support of the MAC concept, a new engineeringprocedure, SAEP-1650 has been developed. ThisProcedure details MAC applicability, executionmethodology, selection criteria, scope boundaries andproposed activity timeline. MAC responsibility and scopeboundaries include:

1. Equipment (DCS, SCADA, TMS, Auxiliary systems,Instrumentation)

2. Engineering Services

3. Construction Services

4. Operation Services

Figure 3 shows the milestones structure should befollowed to capture the benefits realized from MACexecuted projects.

RecommendationThe team recommended that the MAC concept be appliedto all types of Saudi Aramco process automation projects,including Maintain Potential and Master Appropriationsprojects.

Contribution of this initiative goes to all team members:Saleh A. Alqaffas (P&CSD), Riad S. Mosrie (P&CSD),Farrukh N. Chawla (P&CSD), Abdulla A. Al-Mulla (PMT),Kenneth T. Koval (PS&CD) and Wadei A. Al-Marhoon(FPD)

MAC BPPrep.

Bid PackageFinalized

• MAC BidPackage

• PEFS’s rev A• Units• etc.

PP includes:• System sizing and architecture• Implementation plan & executionDuration (Weeks)

• Functional Design specs• Project standards• Site planning data• New Quotation (< Ceiling)(Ceiling = Old Quote +/- Units *Unit rates + contingencies)

WorkTogether

LSTK award

MACBidding

MAC

Sel.

Quotation•Project

LS cost

• Unit rates• etc.

Selection• Award forWork onPP Phase

Design Prep./Basic design Project Proposal phase Implementation Phase

DBSPCompleted PP

Completed

LSTKBP

Design ofPAS

Strategy

Figure 2 MAC Project Timeline

Saleh Al-Qaffas is an Engineering Consultant with Process &Control Systems Department. He holds a BS degree inElectrical Engineerin from the Universsity of Pittsbirgh, USAand an MBA degree from the university of Hull, UK. Saleh isthe Chairman of the Process Control Standards Committeewith Saudi Aramco and the Presidient of the Saudi Arabia

Section of the Instrumentation, Systems & AutomationSociety (ISA).


Oil and Gas Processor Goes Wireless on the LANMohammed Al-Saeed, Soliman Al-Walaie,and Majed Al-SubaieISA InTech Magazine, April 1, 200

Monitoring and Maintaining MultivariableConstrained ControllersJim AndersonMatrikon Users Summit 2007Chicago, Illinois USA, May 9, 2007

Saudi Aramco Control Systems Design and FutureTrends, John KinsleyInvensys Foxboro North America 2007 User’s GroupMeetingChicago, Illinois USA, July 18, 2007

Saudi Aramco Organization & Implementation ofDVR Technology for Performance & EnergyConsumption Optimization, Ashraf AlGhazzawi,Antonio Fernandes and Amein Alsuezi, D.Sc.16h Belsim User Meeting 2007, Barcelona, SpainJune 11, 2007

Centralized LIMS System at Saudi AramcoMuhammad ShahidKhursaniyah Gas Plant ProjectLondon, United Kingdom, March 23, 2007

Application of Multi-Unit Optimization on a NGL Gas Plant,Steve WagnerHoneywell Profit Suite Strategic Users Forum 2007Phoenix, Arizona USA, June 8, 2007

Industrial Wireless LAN Security for Oil & Gas ProcessAutomation NetworksMohammed Al-SaeedThe 8th Annual Gas and Oil Exchange UK 2007United Kingdom, November 30, 2007

Overview of Catalyst Management and SelectionProtocols at Saudi Aramco’s RefineriesSaeed Al-Alloush, Gene Yeh, and A. M. Aitani (KFUPM),Saudi Aramco Journal of Technology Fall 2006

Crude Column Optimization – Saudi AramcoRabigh Refinery case, Khalid S. Al-Otaibi,Salem S Bolawi, Hamad A Sobhi PETROTECH 2007India, January 17, 2007

Foundation for Safety Instrumented Functions (SIF)Patrick Flanders, KFUPM Workshop on Industrial Systems andControl, Dhahran Saudi Arabia, May 21, 2007, ISA Saudi ArabiaSection, Dhahran Saudi Arabia, June 25, 2007, FoundationFieldbus Conference, Abu Dhabi, UAE, Sept 10, 2007

The Effect of Biological and Polymeric Inhibitors onMethane Gas Hydrate Growth KineticsS. Al-Adel, J. Dick, R. El-Ghafari and P. ServioEleventh International Conference on Properties andPhase Equilibria for Product and Process Design,Crete, Greece, May 23, 2007

Legacy Industrial Wireless and the SP100 in Oil and GasProcess Control Systems – Design and PlanningConsiderations, Author: Dr. Abdelghani Daraiseh. Co-authors: Abdullah Al-Nufaii, Barrag Assaf from NorthShedgum Gas Plant, IEEE Gulf Conference, Manama,Bahrain, November 12, 2007


Advanced Multivariable & Regulatory ControlPerformance Monitoring

A technical study was completed in early 2007 to identify, pilot, and evaluate

multivariable control (MVC) and regulatory control (PID) advanced performance

monitoring technologies for use in Saudi Aramco facilities.

A technical study was completed in early 2007 to identify,pilot, and evaluate multivariable control (MVC) andregulatory control (PID) advanced performancemonitoring technologies for use in Saudi Aramcofacilities. The monitoring tools are essential to be able tofully and consistently capture the economic benefits thatsuch MVC applications bring. Currently, Saudi Aramcouses MVC technologies from AspenTech, Honeywell, andYokagawa/Shell.

The Advanced Process Control Unit (APCU) of the ProcessControl Division (PCD) of the Process & Control SystemsDepartment (P&CSD) obtained approval for a TechnologyItem (PRA-02/04-T) for the purpose of identifying, piloting

and evaluating technical capabilities of the major vendorsthat supply such systems and to recommend a limitednumber of vendors that can provide best field provensystems that meet all the requirements for Saudi AramcoRefineries and Gas Plants. The core Evaluation Team wasformed to execute and complete the technologiesevaluation and was comprised of representatives fromP&CSD, Ras Tanura Refinery, Riyadh Refinery, Ju’aymahGas Plant and Yanbu‘ Refinery.

Evaluation MethodologyA Product Evaluation Program was developed to aid inobjectively assessing the various MVC performance

Figure 1Matrikon’s ProcessDoctor uses an ergonomically designed interface that allows a single view of all MVC assets for anentire plant with drill-down capability to easily and quickly detect, diagnose and correct control performance problems.

Authors: Jim Anderson, Mohammed Al-Zain, Dr. Rashid Ansari, Dr. Othman Taha, Abdullah Al-Garni, Khaled Al-Harbi



monitoring technologies. This program was based on thesame principles of previous product evaluationsconducted by P&CSD which were approved by LawDepartment and Contract Review & Cost ComplianceDepartment. This program is based on the Kepner-Tregoe(K-T) Decision Analysis Method.

Results & RecommendationsMatrikon’s ProcessDocTM PID carries the highest ratingand is recommended for all operating facilities to monitorperformance of the regulatory control systems. Inaddition, the Matrikon’s ProcessDocTM MPC and Tai-Ji arerecommended for operating facilities employing MVCtechnologies from either Honeywell (Profit ControllerTM)or AspenTech (DMCplusTM). Currently, Matrikon’sProcessDocTM MPC does not interface with theShell/Yokogawa SMOCTM controller. Matrikon has futureplans to incorporate the SMOCTM technology into itsmonitoring product but there are no specific dates foraccomplishing this. Therefore, facilities which utilizeShell/Yokogawa SMOCTM MVC controllers may useShell/Yokogawa’s monitoring product, MDPro, for thoseapplications.

AspenWatchTM package may be considered for verycomplex DMCplusTM applications. Examples includereactor processes or highly integrated MVC applications.The reasoning for this recommendation is based onAspenWatchTM being designed specifically forDMCplusTM. Consequently, it has very detailedknowledge of the inner workings and capabilities ofDMCplusTM.

BenefitsIt is estimated that the MVC advanced performancemonitoring technology piloted as part of this study willimprove MVC performance by 10%. This performanceimprovement is largely measured as increases in onlineservice time and controller effectiveness or utilizationresulting significant annual savings when used on all MVCapplications within Saudi Aramco. Preliminary data fromthe installed pilots indicate that the estimatedimprovement of 10% is achievable.

Implementation StepsP&CSD issued preliminary recommendations to operatingfacilities in 2006. As a result of the recommendations,several operating facilities budgeted accordingly andpurchased site licenses for Matrikon’s – ProcessDocTM PID,MPC & Tai-Ji. Ras Tanura Refinery purchased a site-widelicense and installed the technology at the end of 2006.Yanbu‘ Refinery and Gas Plant have also completed site-wide installations of ProcessDocTM PID and MPC in 2006and 2007.

P&CSD was able to negotiate a favorable corporatediscounting structure in the Matrikon software contractdue to the large rollout of the product across theCompany. Nine (9) major downstream facilities have nowpurchased site-wide licenses. Berri and Shedgum GasPlants have planned installations in 2007 while the othersare planning for 2008 and 2009. Upstream operations arealso planning installations in 2008.

Jim Anderson is a Control Consultant at Saudi Aramco. Heworks in the Advanced Process Control Unit for P&CSD. Hehas 30 years of industry experience in process controls.

Dr. Othman Taha is a Lead Process Control Engineer withthe Advanced Process Control Unit in P&CSD. He holds a PhDin Chemical Engineering and PhD in Electrical Engineering,with speciality APC control.

Abdullah Al-Garni is a Lead Process Control Engineer atSaudi Aramco’s Ras Tanura Refinery where he works in theEngineering Technical Support Unit.

Khaled Al-Harbi is a Process Control Engineer at SaudiAramco. He works in the Operations and Automation Unitfor Yanbu‘ Refinery.

Dr. Rashid Ansari is a process Control Specialist at SaudiAramco’s Riyadh Refinery. He holds a PhD in ChemicalEngineering with specialization in multivariable control andoptimization.

Mohammed Al-Zain is a Lead Process Control Engineer atSaudi Aramco. He works in the Advanced Process ControlUnit for Ju’aymah Gas Plant. is a Control Consultant at SaudiAramco. He works in the Advanced Process Control Unit forP&CSD. He has 30 years of industry experience in processcontrols.


38


Yanbu‘ Gas Plant Dynamic Optimizer Implementation

This application is primarily

designed to optimize and

coordinate the feed rates to the NGL

fractionation trains subject to

ethane and local non-refrigerated

propane demands. This is the second

implementation of this specific type

of real-time dynamic optimization

technology at Saudi Aramco. It is the

first implementation with a process

scope that encompasses more than

P&CSD/APCU partnered with YG&TDEngineering and Operations groups toimplement a dynamic multi-unit optimizerapplication for NGL fractionation.

one operating area. The Yanbu‘ NGL application

incorporates operating objectives and constraints of

the process areas of three console operators.

Six advanced process control applications were

P&CSD/APCU partnered with YG&TD Engineering and Operations groups to

implement a dynamic multi-unit optimizer application for NGL fractionation.


Author: Steve Wagner

This application

is primarily

designed to

optimize and

coordinate the

feed rates to

the NGL

fractionation

trains subject to

ethane and local

non-

refrigerated

propane

demands.

39


implemented on the three fractionation columns inMod 3 and 4 in 2006. These control applications useHoneywell’s control technology and were designedwith the subsequent addition of this tightly integrateddynamic optimization technology in mind. Theoptimizer application was developed in the firstquarter of 2007 and commissioning was completed atYanbu‘ in April. P&CSD handled most of theengineering in-house.

Console operator interface training was a key concernfor this project. The application scope includes oneconsole area where personnel previously had noexperience with advanced control technologies. Thestandard operating screens for these technologies caninclude large amounts of data and require sometraining and familiarization to be used effectively. Anexample of just one of six standard screens for thedynamic optimizer is shown below.

Since only a select few pieces if all this data are used bythe console operator for control YG&TD controlengineers designed a simpler, focused interface for theconsole operators new to this technology. This stepprovides a better operating tool and significantlyreduced the training required during commissioning.The new custom graphic is shown below. It is tailored

to provide just the key control and related statusinformation.

Initial results of this application show the anticipatedreduction in variability of the feed to the NGLfractionation trains and steadier supply to ethanecustomers. The figures below show before and aftercontrol performance for the ethane header pressure.

The following figures show the related change in thecontrol performance of the feed rates to the NGLfractionation trains. These more gradual changestranslate into better control of key specification on theindividual fraction columns, especially the de-ethanizers.


Stephen Wagner is an Engineering Specialist with theAdvanced Process Control Unit in P&CSD. He has 22 yearsexperience in the areas of process control and refiningoperations. Stephen is a Chemical Engineer and has beenwith Saudi Aramco since 2001. Prior to that, he worked inseveral refineries in Canada with experience in process

control operations and process engineering.

40


Alarm System Improvement at AINDAR GOSP-2

This is the first project to improve a GOSP AlarmManagement System within Saudi Aramco. This articledescribes the data collection setup, summarizes theanalysis results, and recommended resolutions for theimmediate alarm system performance improvement.

Data Collection SetupThe alarm and events messages from AINDAR GOSP-2 arecollected by using the Matrikon Collector via the ExaOPCServer interfaced to the process automation system(PAS),Yokogawa CS3000. The messages are parsed and

DHA00730-SQLT01

ProcessGuard Archiver

LocalProcessGuardServer

CentralProcessGuardServer

Central DatabaseServer

ABQAIQ

AIN DAR GOSP-2

ProcessGuard

Analyzer

ProcessGuard

Web Reports

( MSDE )

Process

ExaQuantumOPC Server

LEGEND

Process

Guard

Collector

DBTEMS 01

ProcessGuard

Excel Analysis

Reports

Internet Explorer

ProcessGuardReal Time Viewer

ProcessGuard Client ApplicationsSoftware Component

PC / Server

BC332172

BC312960

TCP 8541

TCP 8540 /8543 TCP 80 TCP 8542

ProcessGuard

Health Monitor

OPC0162

TCP 8541

Process

Guard

Collector

Yokogawa

ExaOPC

A & E Server

Local DB ( 2GB Limit )

Guard

Archiver

Data stored locally and thenforwarded to anothercollector from which it is sent to the central server


Authors: Saad M. Al-Abbud, Bandar M. Al-Usaimi

Figure 1 ProcessGuard System Architecture

Using an Engineering Services Agreement (ESA), Process & Control Systems

Department (P&CSD) in partnership with North Ghawar Producing Department

(NGPD) provided an alarm baseline assessment, immediate performance

improvement solutions, and recommended resolutions for fixing the top 10 bad

actors at AINDAR GOSP-2.

41


achieved on a local Archiver then forwarded to a centralserver located at Abqaiq for remote alarm managementand analysis. The ProcessGuard System Architectureinstalled for AINDAR GOSP-2 is illustrated below.

Alarm Data Analysis Results SummaryThe alarm data were collected for more than a threemonth period, from February 4, 2007 through May 13,2007. The performance measured by using KeyPerformance Indicators (KPIs) defined in Saudi AramcoEngineering Report SAER-5895, Alarm ManagementGuidelines for PAS.

Many of the performance deficiencies listed in thefindings below are due to an improper alarm systemdesign inherited from the designer, and inappropriateconfigurations exercised by the PAS Vendor. Here is thesummary of the findings and recommendations:

Findings• The tags of the top 20 bad actors have been identified.

More than 25% of these bad actors are caused byinstruments malfunction. Also, alarms on 69 tags havebeen disabled/suppressed due to similar problems. It isrecommended that disabled alarms should be less than30 at any time.

• The average of the configured alarms per analog tagsis 1.6, and the average of the configured alarms perdigital tags is 1.0. The recommended average foranalog tags is 1.0, and for digital tags is 0.4. Theexisting configuration for the both tag types isexciding the recommended average.

• About 96% of the alarms have MEDIUM (HIGH)priority with no LOW priority alarms. This alarmpriority is not aligned with the best industry practicesas defined in SAER-5895, 5% Emergency, 15% High,and 80% Low.

• The different alarm priorities are neitherdistinguishable by color on the displays nor by audiblealarm tones. This severely impacts the operator’sability to focus on prioritizing his actions duringabnormal conditions.

• There is no Alarms Philosophy document available atthe site.

RecommendationsA workshop was held at AINDAR GOSP-2 attended byrepresentatives from P&CSD, NGPD, AINDAR GOSP-2Operation, Engineering, and Maintenance. During theworkshop, proposed recommendations for fixing the top20 bad actors and immediate performance improvementsolutions were discussed. The team agreed on thefollowing recommendations:

• The PAS Alarms need to be re-configured so that thedifferent priorities (Low, High, and Emergency) of thealarms can be distinguishable to the console operator.The alarm indication color should be based on priorityand be consistent through displays on all consoles. Thiswill play an important role especially in an upsetcondition when the Operator can focus on prioritizinghis actions based on alarm priority.

• Immediate implementation of the recommendedresolutions of the top 20 bad actors should beperformed. This will improve the alarm managementsystem by 70%.

• An Alarm Philosophy Document for AINDAR GOSP-2should be developed based on NGPD Management ofChange, and SAER-5895. The Alarm PhilosophyDocument will serve as guidelines to provideconsistent methodology and criteria for thedevelopment, implementation, and modification ofprocess alarms.

Saad M. Al-Abbud is the Alarm Management Optimization(AMO) Lead Engineer at Saudi Aramco. He has activeparticipations in establishing Alarm Management SystemProject Specification, and sites alarm system philosophyDocuments. Led many AMO projects.

Bandar M. Al-Usaimi works in NGPD as a control systemengineer. He has participated in several SAOO controlsystem upgrade projects. Bandar is assigned to lead AlarmManagement System installation as a Pilot Testing anddevelop a deployment plan to the rest of NGPD facilities.


The performance measured by

using Key Performance

Indicators (KPIs) defined in Saudi

Aramco Engineering Report

SAER-5895, Alarm Management

Guidelines for PAS.

Automatic Valve Characterization –Why didn’t we think of that?

Patrick S. Flanders is an Engineering Specialist within theInstrumentation Unit of P&CSD. He is named on 6 patentapplications and is credited with the development of threecommercialized products. He is a registered professionalengineer in the State of South Dakota, USA.

Rienk Tuin is an Engineering Consultant within theInstrumentation Unit of PID. He joined AOC in Holland in1981 and then transferred to SAO in 1987. He is theinstructor for the control valve courses PCI-103 and PCI-204.

Author: Patrick S. Flanders, Rienk Tuin

Figure 1 AVC Valve Performance Correction Method

Figure 2 AVC Device Architecture

This problem has plagued the process control engineer sinceautomation was first implemented in continuous processingfacilities. Conventional attempts to address control valve“non-linearities” involved manual adjustments known as“characterization” within the valve controller ormechanically through the selection and installation of specialvalve internals.

Although possible in theory, the conventional approachesproved impractical as they required manual readjustment tocontrol valve behavior every time the process changed(entire process including the valve and all other equipment inthe loop). Matching the valve characteristic to the processrequirement was difficult enough but each time pipingmodifications were made, pumps turned on or turned off,product build up within the process piping or wear oncontrol valve internals changed the pressure drop seen at thecontrol valve, the process of valve re-characterization wasrequired again. If not re-adjusted, non-linearity would beintroduced with negative impact on the overall control loopperformance.

To address this problem, Process and Control SystemsEngineers, Patrick Flanders and Rienk Tuin proposed a newinnovative solution. They envisioned a new smart valvecontroller that could perform the required corrections in realtime by combining the computing power of advanced smartvalve controllers, continuous feedback of valve stemposition, and process data available at the field level.

With the new Automatic Valve Characterization controller,

the installed valve flow characteristic would be modified toprovide a linear relationship between the input signal to thepositioner and the flow through the control valve (refer toFig. 1). Using this new approach difficult non-linear controlvalve applications will be more easily tuned to provide safeand robust automatic control (refer to Fig. 2).

The invention was documented in a Saudi Aramco patentapplication entitled “Automatic Valve Characterization ofDigital Valve Positioners.” The patent was granted under USPatent # US 7,178,783 on February 20, 2007. Two majorinstrumentation and control system suppliers have showninterest in developing a prototype device jointly with SaudiAramco. As testament to the innovative potential of SaudiAramco, one supplier commented,

“Where do you guys come up with such great ideas?”Another stated, “Why didn’t we think of that?”

42



Control valves and their performance play a major role in the automation of Saudi

Aramco facilities. The need to adjust or correct the off-the-shelf flow characteristic

of a control valve to achieve linear control action once installed in the process is not

a new problem.

Input Signal

Process Measurement

(Flow or Differential Pressure)

AVC provides a linear relationship between the input signal to thepositioner and the flow through the control valve.

Control Valve

Digital Valve Controller

Valve PositionFeedback

Pneumatic Output

to Valve

AVC

AVC Device Architecture

43



Key Elements for Oil & Gas Wireless Networks

With a globally distributed design/build process andsupply chain, a demand-driven market, the rapid needs todeploy technologies such as wireless to enhancenetworking capabilities. With the need for secure real-time response across the process control and enterprisenetworks, companies are facing difficult challenges andcomplex integration.

A shift is taking place across all of the process automationindustries. Information itself is becoming the engine thatruns the operation. From product developmentengineering to production operations and extended todistribution, information from all domains must beshared across the operation stages and lifecycle, andthroughout the enterprise networks.

To that extent, the SP100 (wireless for automationsystems) is expected to becoming a basic building block ofthe plant networks and a means for carrying informationwithin and outside the oil and gas plant premises. Thisarticle will tap on the wireless key elements for processautomation networks and show the coming industrialwireless standards in addition to addressing therequirements for oil and gas applications

ISA SP100SP100 is a work group within ISA (Instrumentation,Systems and Automation society) tasked with developinga new wireless standard for process automation system.The SP100 wireless standard for process automationsystems is applicable to industry such as oil & gas,petrochemical and manufacturing. The standard of SP100is under development and is intended to be used in 2.4GHz band in the first release.

Key Elements for Wireless PlantNetworks:The key factors of selecting wireless for an application aresingle industrial standard, reliability of data, wirelesssecurity, sensor battery life, and single network for manyapplications as seen in the above figure.

In several wireless projects in Saudi Aramco, there are a number of

requirements in any future wireless system that should be factored

into connecting various plant equipment or systems, as follow:

• The wireless system should be certified to work in a hazardous

area.

• Support mesh topology.

• Low latency.

• Operate in extreme environment “high temperature and

humidity.

• Have a strong level of wireless security, as described in SP100.

• Provision for device to be battery operated

• Employ frequency hopping to reduce the effect of interference

and fading

• Scalable for additional nodes

• Can support different types of physical connections, e.g.,

Ethernet, serial, etc.

ConclusionWireless data reliability and security are the most criticalaspects of SP100 design, as seen by the users. Properwireless design practices, cost effectiveness, and businessneeds mandate that a single wireless network withmultiple applications is used as a model for our plants. Forthe first phase, we anticipate that most applications usingwireless will be for monitoring and alerting. There arefew plans in the market to eventually use wireless forcontrol. Many wireless applications are new – notpreviously measured with wired devices.

Factors Influencing Use of Wireless

Percentage

Abdullah Al-Nufaii is a Communications Engineer withinCCNU of P&CSD. He joined Saudi Aramco in 1994 with morethan eleven years of experience. He has a Masters Degree inTelecommunications and an SDP candidate.

Dr. Abdelghani Daraiseh is an Engineering Specialist withinCCNU of P&CSD. He has 17 years of industrial experience inwireless networks and security. Previous to joining SaudiAramco, he worked in the USA with Nortel Networks, and aCenter for Wireless R&D.

Author: Abdullah Al-Nufaii, Dr. Abdelghani Daraiseh

Most Oil & Gas companies today are exposed to one of the most complex and

diverse business environments in process automation history.


Industrial Time SynchronizationFor Oil and Gas Process Automation Networks

This will guarantee same clocking reference is used forthe various industrial process applications such as SCADA,DCS, VMS, PMS, etc. Lack of a coordinated accurate timestamping for recorded events makes any reconstructionof a timeline difficult and time consuming, if notimpossible.

Time synchronization and accuracy might not beimportant to some organizations especially those whohave mostly stand-a-alone and closed application servers.For other organizations that depend on distributed andinteracted systems to automate their work such as oilrefineries and oil/gas plants, time synchronization is a keyissue that needs to be always maintained across allapplications and devices in PAN. There are different waysto provide time synchronization over industrial datanetworks. Two popular ways are Network Timing Protocol(NTP) and the newly released IEEE protocol PrecisionTiming Protocol (PTP).

The NTP (RFC1305) is a protocol for synchronizingindustrial equipment’s clocks across the network tostandard time. These equipments and devices should beEthernet-based, e.g. workstations, HMI, RTU, PLC,Wireless Gateways, Switches, Routers etc.

NTP version 4 can provide time accuracy of 10 millisecondsover the Internet but can maintain time accuracy of lessthan 200 microseconds over Local Area Networks.

NTP architecture consists of hierarchical stratums levels(fig.1), which defines the distance and accuracy from thereference clock.

The primary stratum (stratum 0) consists of devices such asGPS, atomic, or radio clocks. The next stratum level(stratum 1) contains servers that are directly connected to

Figure 1 NTP timing architecture

Authors: Majed M. Al-Subaey, Soliman Al-Walaie, and Mohammed A. Al-Saeed


Industrial communications and data networking equipment such as routers,

switches, wireless devices and access points are used to interconnect PAN

infrastructures. Because of the multiple systems and applications, it is very crucial

to use precise and common master time reference to synchronize all systems and

ensure accurate time stamping consistency for all Oil and Gas plants operations.

For other organizations that

depend on distributed and

interacted systems to automate

their work such as oil refineries

and oil/gas plants, time

synchronization is a key issue

that needs to be always

maintained across all

applications and devices in PAN.


the primary stratum while stratum 2 consists of industrialdevices that send NTP requests to stratum 1 servers and soon as shown on the following figure.

Ju‘aymah Gas Plant (JGP) expansion project is an examplewhere NTP is implemented for accurate and consistenttime stamping for all sequence of events (SOE) andalarming. Time synchronization was accomplished byemploying NTP time sync approach for plant wide systemsand applications.

In JGP expansion project, NTP server with GPS antennareceiver will be installed and configured to be connectedto Vnet/IP layer 2 switches. NTP server will act as acommon master clock server over the Vnet/IP networkwhile clients connected to the Vnet/IP network will beequipped with SNTP client function to time synchronizewith NTP server on the same Vnet/IP network. Othersubsystems that are not on the Vnet/IP network can besynchronized by directly connecting them to the NTPserver via LAN ports (Ethernet) or serial ports (RS232).

The main challenge with NTP is that its timing signals aredelayed by the Operating System (OS) since its packets gothrough the physical and Data Link OSI Layers in thenetwork switch as any other data packets. Thus, this haslead to the development Precision Timing Protocol (PTP).

The PTP provides better timing accuracy by resolving theNTP problem using hardware Time Stamping Unit (TSU).This unit is placed between the Data Link and physicallayers to monitor the packets over the inbound andoutbound traffics and issue a precision time stamp whena PTP packet is recognized. PTP is applicable to be used inapplications that have high demands on accuracy andusing dedicated networks. NTP is used for applicationsusing Local Area Network, Wide Area Network, andInternet.

In conclusion, both timing protocol standards (NTP andPTP) can be deployed on PAN to provide preciselyaccurate common timing for the various processapplications such as DCS, SCADA, PMS, TMS, etc. Thissolution can be integrated seamlessly with the existingnetwork infrastructure as well as providing a robust andefficient mechanism to support timing over IPapplications. Both NTP and PTP protocol can be extendedin any deployment by utilizing the Global PositioningSystem (GPS). NTP and PTP with GPS are now widely usedin closely coupled real-time control systems that requiresynchronization in the range of mili-to micro-seconds.Furthermore, PTP is more used in motion controlautomation systems such robotics, and othermanufacturing applications.

Soliman Al-Walaie is a communication engineer within thecommunications Unit of P&CSD. He is a certified wirelessnetworks professional (CWNP) engineer and has twelve yearsof experience. He is the instructor of CommunicationTransmission Systems (CTR205)

Mohammed A. Al-Saeed is working for Saudi Aramco inProcess & Control Systems Department/ Process Instru-mentation Division. He graduated from King Saud Universityin 1995 with a bachelor degree in Computer Science inInformation Systems. He first worked with Saudi ArabianTexaco Inc. as a Network Specialist for six years. In 2001, hejoined Saudi Aramco in P&CSD as Industrial ComputerEngineer. He obtained a Master of Business Administration(MBA) and five technical certifications, Certified WirelessSecurity Professional (CWSP), Cisco Certified DesignProfessional (CCDP), Advanced Wireless LAN Design Specialist(AWLDS), Cisco Certified Design Associate (CCDA), CiscoCertified Network Associate (CCNA). His specialty is ProcessPlant Networking and Systems Engineering. He is a memberof ISA and IEEE professional societies.

Majed M. Al-Subaey is a Computer Engineer working forSaudi Aramco in Process & Control Systems Department/Process Instrumentation Division. He graduated with aBachelor of Science degree in Computer Engineering fromKFUPM in 2000 and obtained a Master degree in IT Universityof Liverpool, UK in 2005. Currently, he is pursuing Ph.D inNova Southeastern University, Florida, USA in InformationSystems, area of interest Information Security. He is an MCSEsince 2001 and a Sun Certified Programmer in Java since(SCPJ) 2004.


The main challenge with NTP is

that its timing signals are

delayed by the Operating System

(OS) since its packets go through

the physical and Data Link OSI

Layers in the network switch as

any other data packets.

Furthermore, PTP is more used

in motion control automation

systems such robotics, and

other manufacturing

applications.


Trim Integrity for Compressor Anti-surge Valves

Process ChallengesValve trim parts are expected to continue in operation(with minimum wear and tear) until the next plant orequipment turndown. They have to be selected to becapable of handling the following process challenges:

• flow induced noise and vibration

• sudden flow gust

• high energy dissipation

• spare flowing capacity

• seating area leakage

• low travel throttling

AnalysisI) Plug Designs1. The Solid Plug Design

The solid plug design is rugged, less susceptible tovibration and friendly to machining. Its excessive weight,however, makes it economically unattractive.

2. The Skirt Plug Design (Figure 1)The skirt plug design overcomes plug weight concernsand therefore helps achieving better stroke speeds. Thedesign however is more susceptible to vibration.

3. The Spoked Plug Design (Figure 2)

The spoked plug design is considered the optimal plugdesign. Weight and susceptibility to vibration are top-quality. Because of its difficult geometry, this design facesmanufacturing challenges.

II) Plug/Stem Connection Methods1. The Screw & Pin Method (Figure 3)

Because of its simplicity and suitability to sour and sweet

Figure 1 The Skirt Plug Design

Figure 2The SpokedPlug Design

Figure 3 The Screw & Pin Stem/Plug Connection Method

Author: Mohammed Al-Juaib

Recently, performance analysis of anti-surge valves is focused on the quality ofresponse (speed, overshoot, set point tracking, etc.) The research work, addressingthe above, is predominantly concerned with the actuating system (actuator,positioner, boosters, etc), with very little or no emphasis on the selection of thevalve internal components (mainly the trim parts). Concerns, such as valvevibration, noise, trim damage, plug jam and loss of the tight shutoff, need to beaddressed and resolved.

Drilled


Drilled Hole Cage (inwards tapered)

Flow in

Flow in

Drilled Hole Cage (outwards tapered)


process conditions, the screw & pin method is the mostfavorable plug/stem connection method. Designers arecautioned when specifying this method for highDifferential pressure (DP) applications as the screw & pinsintegrity degrades significantly.

2. Welding Method

Welding the stem to the plug is a more robust connectionmethod. It is limited to sweet services since weldingintroduces complications with the corrosion resistance ofthe base metal.

III) Plug to Cage ClearanceMinimum clearance (between the plug and the cage) isrequired to ensure negligible frication and to keepclearance flow to minimum. Clearance flow (Figure 4)causes series trim damage particularly in high DPapplications as it causes plug vibration and rotation. Thiscan be eliminated using tighter clearances or if plugmodifications, like including a lower piston ring, areimplemented.

(IV) Cage DesignCage design primarily addresses noise reduction andenergy dissipation. In a typical drilled-hole cage design,the size and spacing of the holes impact valve capacityand noise in the following manner:

• Small hole sizes reduce noise better than large onesbut reduce capacity. Smaller holes introduce higherfrequency jets which are harmless to the valve and itssurroundings (piping/structure).

• Large hole spacing reduces noise better than smallhole spacing but reduces capacity. Larger hole spacingminimizes the probability of jet interactions. Whenjets interact, they produce combined jets that vibrateat the low frequency spectrum.

• Tapered outwards (Figure 5) holes tend to vibrate athigher frequencies but minimize capacity. Taperedinwards holes have exactly the opposite effect.

ConclusionIt is essentially important to:

• carefully verify process conditions

• thoroughly review vendor proposal(s)

• communicate with vendors to resolve designuncertainties

• before shipment, conduct necessary factory testingand inspection to validate selection

• conduct online site testing, monitor performance andlog deficiencies

Cage

PLUG

Pi

Seat

Figure 4 The Effect of Clearance Flow

Mohammed Al-Juaib is an instrumentation engineer withthe Instrumentation Unit/PID. He has 13 years experiencewith Saudi Aramco. He worked as an instrumentationengineer in Ju‘aymah Gas Plant, Riyadh Refinery andHaradh Gas Plant.


Figure 5 A Typical Drilled-Hole Cage Design


Industrial Wireless LAN SecurityFor Oil & Gas Process Automation Networks

While security remains to be the major concern, it shouldbe robust following a well defined standard and meetingthe industrial safety and security regulations includingpremises protection and detection of rogue nodes.Industrial WLAN technologies include four main suitesnamely IEEE802.11a, b, g and n (known as WiFi).Currently, there are three dominant WLAN standards inthe market 802.11a, b, and g as shown in Fig.1. On theother hand, IEEE802.11n is a newly developed standard“final approval stage” that will boost WLAN capacity to200Mbps and above. WLAN is an open standard solutionand can be considered as “Wireless Ethernet” since it usespretty similar to the original Ethernet access mechanism“CSMA/CA.”

Since WLAN broadcast data into the air using “radiosignals,” securing WLAN networks becomes very crucialfor process automation networks and systems.

The three key wireless security factors are authentication,encryption and data integrity.

Wireless Access AuthenticationAuthentication is a process of verifying users or devicesidentity and credentials. Users or devices should presentcredentials such as passwords or digital certificates to forverification. Media Access Control (MAC) address isconsidered as a weak verification identity since it can bespoofed and changed easily.

Successful authentication of user and device would resultin authorizing that specific user or device to grant accessto network resources and services. (Fig.2)

Encryption and Data IntegrityData confidentiality and integrity of transmitted dataover the air can be achieved by applying encryptiontechniques.

There are two main encryption mechanisms in WirelessLAN solution which are:

• Rivest’s Cipher (RC) which is being used in the WiredEquivalency Privacy (WEP) and the Temporal KeyIntegrity Protocol (TKIP) or Dynamic WEP. Due to itsencryption weakness, WEP encryption algorithm didnot provide the level of security necessary forcorporate and critical process automation applications.

• Advanced Encryption Standard (AES) which provides arobust enhancement to the aforementioned TKIP andits RC encryption. AES encryption algorithm performshashing as well as advanced encryption.

The new IEEE802.11i WLAN security standard wasapproved in June 2004 and addresses robust securityprotocols and encryption algorithm (AES). This resulted in

Several remote facilities, processes and field operationsmay utilize this connectivity to access a PAN which wouldresult in improving productivity, less downtime, fasterand more accurate data analysis and reduced capital andoperating expenditures. This technology is the mostextensive deployment in the industrial environment andhas a potential to be deployed more in the future. Due toits flexibility, fast deployment, cost reduction, andsimplicity, it is considered to be an attractive solution toindustry.

Security Threats in Industrial WLAN Securing and protecting industrial networks and systemsis very critical. First of all, these systems are mission-criticaland should be up and running round-the-clock. Also, thenew technologies are changing rapidly as well as movingto open standard in terms of protocols and operatingsystems. In addition, recent studies reported a significantincrease in virus attacks and hacking incidents over theInternet.

802.11a 802.11b 802.11g 802.11n

IEEE Ratification 1999 1999 2003 2008

RF Technology OFDM DSSS DSSS/OFDM DSSS/OFDM

Max Data Rate 54 Mbps 11 Mbps 54 Mbps 200+Mbps

Frequency 5 GHz 2.4 GHz 2.4 GHz 2.4/5 GHz

Author: Soliman Al-Walaie, Mohammed A. Al-Saeed,Majed M. Al-Subaey


Industrial Wireless Technology can be applied in several process automation

applications such as oil/gas well heads automation and vibration monitoring

system. This solution must ensure security, interoperability, coexistence, quality of

service, reliably and scalability.


overcoming attacks on privacy, integrity, andauthentication.

ConclusionsModern Industrial WLAN security has matured bycombining data confidentiality and integrity,authentication and access control as well as intrusiondetection and protection mechanisms. The securitymethods used by the original 802.11 standard proved tobe relatively weak. The 802.1X standard was adapted for802.11 wireless networks to provide much strongerauthentication and automated encryption keymanagement. It is recommended to use WPA2 productcertification for the security features of the IEEE 802.11istandard. That includes mandatory use of AES forencryption and data integrity.

Figure 2 WLAN Authentication architecture

Mohammed A. Al-Saeed is working for Saudi Aramco inProcess & Control Systems Department/ Process Instru-mentation Division. He graduated from King Saud Universityin 1995 with a bachelor degree in Computer Science inInformation Systems. He first worked with Saudi ArabianTexaco Inc. as a Network Specialist for six years. In 2001, hejoined Saudi Aramco in P&CSD as Industrial ComputerEngineer. He obtained a Master of Business Administration(MBA) and five technical certifications, Certified WirelessSecurity Professional (CWSP), Cisco Certified DesignProfessional (CCDP), Advanced Wireless LAN Design Specialist(AWLDS), Cisco Certified Design Associate (CCDA), CiscoCertified Network Associate (CCNA). His specialty is ProcessPlant Networking and Systems Engineering. He is a memberof ISA and IEEE professional societies.

Soliman Al-Walaie is a communication engineer inP&CSD/CCNU. He is a certified wireless networks professional(CWNP) engineer and has twelve years of experience. He isthe instructor of Communication Transmission Systems(CTR205).

Majed Al-Subaey is a Computer Engineer working inPID/CCNU. He graduated with a Bachelor of Science degree inComputer Engineering from King Fahd University ofPetroleum and Minerals in 2000 and obtained a Mastersdegree in Information Technology from the University ofLiverpool, UK in 2005. Currently, he is pursuing his Ph.D inNova Southeastern University, Florida, USA in InformationSystems, area of interest Information Security. He is aMicrosoft Certified Systems Engineer (MCSE) since 2001 anda Sun Certified Programmer in Java since (SCPJ) 2004.


WLAN is an open standard

solution and can be considered

as “Wireless Ethernet” since it

uses pretty similar to the

original Ethernet access

mechanism “CSMA/CA.”


Process Automation Focus Team Update

The Process Automation Focus Team (PAFT) has beenactive this year. One significant technology item,Advanced MVC/PID Performance Monitoring, wassuccessfully implemented and closed in February. Theresults and recommendations have been published asSAER 6166. In addition, four new technology items havealready been approved in 2007 with another item in thefinal stages of approval. This represents a significantupswing in technology program activity and underlinesthe emphasis that management has placed on technologydevelopment and implementation.

The Process Automation Focus Team (PAFT) activelyidentifies and sponsors new process automationtechnologies that can be successfully implemented inpartnership with operating organizations throughoutSaudi Aramco. All new technology items are led by a teamof engineers from both P&CSD and partnering operating

organizations. Funding and logistical support fortechnology items is provided by the Engineering Servicestechnology program.

Currently there are 12 active process automationtechnologies and PAFT is actively seeking to identify newtechnologies that have the potential for high potential toimprove economic or safety performance of ouroperations.

Figure 1. Active Process Automation Technology Items

PRA-01-/03-T

PRA-01/04-T

PRA-01/05-T

PRA-02/05-T

PRA-01/07-T

PRA-02/07-T

PRA-03/07-T

PR-05/07-T

PCD-04/04-T

PCD-06/04-T

PCD-01/02-J

PCD-02/03-3

Programming for Commercialization ofPAS Obsolescence (SAEP135) JAM#3327

Local Emergency Isolation ValveController with FF-S15 Communications

Natural Gas Liquids RecoveryImprovement via Empirical ExperimentalMethod

Automating Gas Custody TransferMeasurement Systems

Online Mercury in Natural Gas Analyzer

Welhead Flowing Protection System withAutomatic Testing and Diagnostics

Evaluation of Nanotechnology MetalOxide Semiconductor (NTMOS) H2S GasDetector

On-line Oxygen Analyzer for ThermalOxidizer

High Speed Digital Subscriber Loop(HDSL)/Wireless Remote Monitoring forUltrasonic Liquid Flow Sensing Meter

Field Mounted Gas Chromatograph

Standards and Deployment of WirelessLocal Area Networks

Packet Communications

9/30/2007

9/30/2008

6/30/2008

6/30/2008

6/30/2008

12/31/2010

3/31/2008

6/30/2008

6/30/2007

12/31/2007

3/31/2007

12/31/2007

Nasser Y. Assiry, Deraid Herling, JohnGrainger, Gregg Skinner, Others

Patrick S. Flanders

Othman Taha, Salah A. Al-Ali, HenryH. Chan.,

Mohammed Salim, Abdelghani A.Daraiseh, Hassan A. Amer, AbdullatifA. Saadoun.

Suryanarayana Vedula, KhaliJehairan

Patrick S. Flanders, Mohmmed K. Al-Juai, AbdulJail A. Al-Hawai

Saeed M. Al-Abeediah, Saad Al-Ali

Suryanarayana Vadula, Riyadh H.Fares

Soliman M. Aimadi, Soliman A. Al-Walaie, Mohammed Salim, D.W.Burkel/S. Al-TwaijriSuryanarayan Vedula, James L.Spranque

Abdelghani Daraiseh, Rushdi H.Muammar, Khalid S. Al-Ghamdi,Abdullah S. Nufail

Soliman M. Almadi, Soliman A. Al-Walaie, Hussain A. Al-Salem, FouadM. Khabbaz

Item Number Technology Title End Date Team Members

Douglas S. Esplin is a registered Professional Engineer in thestate of Utah and has 25 years of process control experience.He has been with Saudi Aramco for a total of 13 yearsworking in the RT Refinery and P&CSD. He is an EngineeringConsultant with the Process Automation Systems Unit inP&CSD and the leader of the Process Automation FocusTeam.

Author: Douglas S. Esplin



Engineering the FutureAuthors: Saleh Al-Qaffas, Luay Al Awami, John Kinsley, Patrick Flanders

Process & Controls Systems Department recentlyparticipated in the first ISA-KFUPM Student ProjectCompetition. The event was held on May 21 duringKFUPM's Workshop on Industrial Systems and Control(WISC-2007) and was attended by more than 300professionals. The event was coordinated between theSystems Engineering Department of King Fahd Universityof Petroleum and Minerals (KFUPM) and theInstrumentation, Systems and Automation society (ISA).P&CSD engineers from the Process InstrumentationDivision and the Process Controls Division serve as boardmembers of the local Saudi Arabian section of ISA andwere responsible for organizing the event. Saudi Aramcowas one of six sponsor companies which generouslyprovided funding for the competition. SABIC, Yokogawa,Invensys, Honeywell and Emerson also participated insponsoring the event.

The competition enabled the students to put theirtheoretical studies to work solving real world industrialproblems. The focus of their work was to apply theprinciples of industrial control and automation toenhance industrial processes. As part of the mandatoryengineering curriculum, students are required tocomplete a project in their field of study. These projectsserved as the basis for the competition which featured ademonstration and presentation of six student projects.Projects were pre-selected by the KFUPM faculty prior tothe competition. Dr. Fouad Al Sunni and Moustafa El-Shafei from the Systems Engineering department wereresponsible for pre-selecting the six projects. During thecompetition, each student provided a demonstration ofhis project and was required to give a 15 minutepresentation to discuss the nature of his work. Projectswere judged based on technical content andpresentation. A panel of judges scored each project andwinners were chosen in two categories; Applied

Automation and Innovation. A representative from eachof the sponsor companies was selected to serve on theJudge's Panel. P&CSD manager, Saleh Al Zaid representedSaudi Aramco on the judge's panel. Other members of thejudge’s panel included: Mr. Abdulaziz Al-Najim, Manager,Engineering and Project Management Department,SABIC; Mr. Toshiaki Shirai San, Vice President, Research &Development, Yokogawa; Mr. Salem Al Khaldi, BusinessDevelopment Manager, Invensys Saudi Arabia; Mr. AbbasAlelg, Senior Engineer, Honeywell Advanced ProcessSolutions; and Andrew Dennant, Technical Manager,Emerson Process Systems.

All of the students worked very hard on their projects andproduced excellent work. The judges had a challengingtime selecting the best from the six projects presented.Each student was presented with a plaque for theirparticipation and the winners received a trophy and gift.The winner in the category of Innovation was AshrafDasah for his project on "Inherent Flow Characteristics."He developed a method to programmatically adjust flowcharacteristics of a control valve. The system monitoredline pressure and automatically adjusted the valvesignature curve to compensate for fluctuations. Thisenables the valve and therefore the control system tomaintain accurate flow control over a wide range of linepressures. KFUPM has filed for a patent with the U.S.Patent and Trademark Office to obtain intellectualproperty rights for that idea. The university is hoping topartner with local manufacturers in the commercial

KFUPM students gather with other event participantsfor a group photo.

Ashraf Dasah explains the benefits of his project toISA section President Saleh Al-Qaffas and SaudiAramco, Process & Controls Systems DepartmentManager Saleh A. Al-Zaid.

Luay Al Awami, left, Vice President of theInstrumentation, Systems and Automation Society,presents the award in the category of AppliedAutomation to Mohamed Khan.

Prepare the workforcefor the Future



development of the technology and eventually marketthe idea to petrochemical companies, including SaudiAramco.

The winner in the category of Applied Automation wentto a project that involved automation of an assembly line.This project was developed by Munir Kulaib andMohamed Khan, based on work done during aninternship assignment with Al-Zamil Company at an airconditioner manufacturing facility. The studentsdeveloped a system to automate tracking and qualityassurance checks during the assembly process. This workwas being recorded manually by workers at themanufacturing plant. Individual components werescanned as they entered the assembly line and monitoredas they moved through the assembly line. Quality checksdone during the assembly process were automaticallylogged into the system and stored in a database againstthe actual part. This enabled a complete record of eachair conditioner to be automatically recorded during theassembly process and automatic generation of shiftproduction reports. The students estimated that therewould be a net gain of 7% in production efficiency byimplementing the system while minimizing the potentialfor human error. Based on this work, Zamil decided to goahead and implement the system at their actualmanufacturing plant.

Other projects which were not selected included"Multivariable Controller of Single Screw Extruder forPolymer Applications,” developed by Waleed Abdul-Ate.He developed a multi-loop control algorithm to controlextruder temperature. A mini-extruder was built usingelectric heaters fixed to the screw in three stages. Waleedimplemented a feed-forward algorithm enable final exittemperature to be more precisely controlled. This type ofcontrol could potentially be used by SABIC and otherpetrochemical companies.

Another student developed a system to monitor vibrationlevels in rotating equipment. The system used a simulatorwhich enabled him to manually manipulate vibrations ona rotating shaft. Input sensors captured the vibrationsignatures at various levels and were stored at in thesystem. Once vibration signatures were captured atseveral levels, the system then compared the real-timelevels against those stored in the database. The systemthen produced a alarm to alert the operator whenvibration levels exceeded preset values.

Another project involved a simulated heat exchangersystem and was developed by a team of four students.The system utilized a cascade control scheme which usedtank temperature as the primary control variable. Theprimary temperature control was tied to a flow controller,which adjusted the flow of hot water running through a

tube submersed in the tank. The equipment and controlalgorithm were designed and built by the students.

The final project was an automatic syringe for chemicalapplications. This project was developed by Wael KhalidZaitouni and Abdelrahman Shbair. The system automatedthe measurement of very small and precise quantities ofliquid using a syringe. The operator enters the quantity ofliquid material desired into a computer system. Thecomputer then automatically controlled the amount offluid drawn into the syringe and then applied the fluid toa vessel.

ISA is a worldwide professional society forInstrumentation and Controls professionals. There areover 30,000 ISA members worldwide. The Saudi Arabiansection or ISA has over 250 members from many differentcompanies across the Kingdom as well as KFUPM facultymembers. P&CSD engineers from both theInstrumentation and Controls Divisions are boardmembers for the Saudi Arabian section of ISA. They areresponsible for organizing monthly technical meetingsfor ISA members across the Kingdom. Board members ofthe ISA Saudi Arabia section include: Saleh Al-Qaffas,President; Luay Al Awami, Vice President; John Kinsley,Secretary ;and Patrick Flanders, Treasurer. Thecompetition was organized to try to build a strongerbond between industry and academia. The event wassuccessful in accomplishing this goal and ISA is planningto continue this event on a yearly basis.

Saleh Al-Qaffas is an Engineering Consultant with Process &Control Systems Department. He holds a BS degree inElectrical Engineerin from the Universsity of Pittsbirgh, USAand an MBA degree from the university of Hull, UK. Saleh isthe Chairman of the Process Control Standards Committeewith Saudi Aramco and the Presidient of the Saudi ArabiaSection of the Instrumentation, Systems & AutomationSociety (ISA).

Luay Al Awami is an Engineering Specialist with theInstrumentation Unit of P&CSD. He is also the Vice Presidentof the Saudi Arabian section of the Instrumentation, Systemsand Automation Society.

John Kinsley is an Engineer with the Process AutomationSystems Unit of P&CSD. He is also the Secretary of the SaudiArabian section of the Instrumentation, Systems andAutomation Society.

Patrick Flanders is an Engineering Specialist with theInstrumentation Unit of P&CSD. He is also the Treasurer ofthe Saudi Arabian section of the Instrumentation, Systemsand Automation Society.



Safety of the Issue

Relief valve relieving rates are based on several criteriathat lead to overpressure in vessels. The cause ofoverpressure without going into detail can be attributedfor example to: reflux failure, utility failure like electricalpower, cooling water, instrument air, failure due toaccidental fires outside vessels, etc. The relieving load foran individual relief valve is then based on any one orcombination of the above cases that is controlling; insome cases the fire case (fire outside vessel) is thecontrolling case. This paper suggests engineers to becautious about how though the limiting case may be thefire case, the relief valve could still be ineffective toprotect the vessel as designed, and the vessel may failprematurely to everyone’s surprise.

Accidental fires outside vesselsIn a plant a pressure vessel may be exposed to externalfire due to ignition of hydrocarbons that leaked in thearea. The heat released from the open free burning firewill be absorbed by the vessel by radiation or by directimpingement of flame/hot gases on the vessel wall.

Caution on relief valve design for fire caseAre we safe?The answer depends on the design engineer on how heapplies the Standard (SAES/API). When reviewing design,one must exercise caution as follows:

Caution:

Many a times simulation calculations will show someliquid being knocked off in the separator vessel; typicallybased on the simulation, design contractor will assume awetted surface (liquid level in the vessel) within 25 ftelevation from grade, irrespective of the rate at whichliquid builds up in the vessel; but in reality the vessel insome cases may have negligible or no liquid, so in shortthere is no wetted surface1 inside the vessel. The relievingrate for the relief valve (RV) is then calculated for fire caseas if there was liquid in the vessel and this rate is used forRV design if it is the controlling case; consequently thevessel is designed with no external fire protection aswetted surface is assumed.

Let us assume that we have an non-insulated KO drumthat is subject to accidental fire outside the vessel. Theheat released will be absorbed by the vessel and walltemperature will begin to rise.

If there is liquid in the vessel as assumed in the design,then we have a wetted surface that will ensure the vesselwall temperature does not rise excessively as liquid insidethe vessel evaporates. This however will increase vaporrate in the vessel leading to increased pressure in thevessel. If we have a control system it will relieve excesspressure to the flare, but if pressure keeps rising the RVwill pop eventually and relieve the pressure. The systemwill be protected. The above scenario is what is normallyenvisaged by the designer based on assumptions thatthere will be liquid level inside the vessel. If the vessel hadnegligible or no liquid in it, the vessel wall temperaturewill rise and temperatures could soon reach above 1000˚ F,consequently the vessel wall will not be able to containthe stress from the normal operating pressure and couldhave a catastrophic failure at operating pressure.

To explain this further let us look at an example- refer toFigure 1:

Vessel size: 78 in (d) x 14ft 6 in (h)

Vessel wall: 1.1875 in thick.

Design Pressure: 440 psig

Operating Pressure: 330 psig

Design Temp: 200F

RV set at 440 psig.

Service: Fuel Gas

Vessel has no insulation.

HOT SPOT

Figure 1 Vessel Drum

Author: Gabriel T. Fernandez

Caution on relief valve design for fire incidents Are we safe?



In the event of an accidental fire outside the vessel, theheat released will be absorbed by radiation or by directimpingement of flame/hot gases on the vessel wall. Withno liquid inside the vessel (no wetted surface), walltemperature will begin to rise with negligible effect onthe vessel pressure. Figure 2 shows the allowable vesselpressure vs wall temperature.

We notice that beyond 650˚F the allowable vesselpressure drops very steeply. At 1000˚F the vessel cannotoperate above 75 psig, this implies that if the processcontinues to operate at normal operating pressure of 330psig it could have a catastrophic failure once the walltemperature exceeds 800˚F. Referenced Standards datashows this could happen in less than 10 minutes.

To avoid such lapses in design, the reviewing/design engineer must verify if the vessel designed for afire incident will contain liquid under normal operations,and this is based on experience. If it does not contain awetted surface then ensure the following for a safedesign.

• Design should include remotely controlled depres-surizing control besides an inlet ZV.

• Providing insulation on vessels such that theinsulation will not be removed from the surface dueto fire. This will effectively limit heat input.

• If no insulation was provided then ensure that thevessel can be cooled with water either from properlyplaced fire monitors or deluge/spray systems.

• Ensure drainage is provided, and it must be away

from the vessel such that there is no accumulationunder the vessel.

• It is important to verify these points early in thedesign to avoid future compromise solutions andschedule/cost impact.

Though information regarding proper design is availablein Saudi Aramco and API standardsRef, the designersinterpretation may not necessarily meet the intent of thestandards. The above caution is intended to focus theattention of the design review team to such lapses.

The article was prompted from the review of several designs madeby reputed design contractors that missed such analysis to ensureprotection was indeed guaranteed. Please refer your concerns toFlare and Relief Systems Unit.1Wetted surface of a bare vessel is where the liquid content liesagainst the inside surface of the outer wall of the vessel.References: for further information;

• SAES-J-600

• SAES-B-006 Section 6

• API 521 5th edition; Section 5.15.

0

0

100

200

300

400

500

600

100 200 300 400 500 600 700 800 900 1000 1100

Vessel wall temp vs Max internal pressure

temp F

pre

ssu

re p

sig

Gabriel T. Fernandez is a Professional Engineer working as aProcess Engineering Specialist in the Upstream ProcessEngineering Division of P&CSD. He holds a Bachelors degreein Chemical Engineering from IIT Kanpur, and has aProfessional Engineers license from Alberta, Canada(APEGGA).

His 30 years of experience has been in design/plantengineering and operations of Crude Oil processing, Oilsands, Lube Refining, Utilities & Offsites, and Processengineering with Engineering Company.

Figure 2 The allowable vessel pressure vs wall temperature



ViewpointI recently had the opportunity to get to know a strong group of

professionals when asked to cover the Manager position for

three months. Although I have been with the Company for 14

years, many of the technology areas within P&CSD were

unknown to me. Actually, what I realized is that frequently

P&CSD operate in the background by providing support to other

departments. The heart of our plant operations is composed of

processes and control systems, and P&CSD is charged with the

responsibility of ensuring that the Engineering Standards are

kept up to date and are at the leading edge of technology,

especially in the arena of control systems.

The wealth of knowledge in P&CSD far surpassed my

expectations, this department truly has talented individuals.

Their experience has been gained through plant operations in

oil production, gas processing and refining. One of the key

support functions is toward capital programs, by working with

Facilities Planning and Project Management. With the size of

the current capital program, P&CSD is vital to the success of all

of these projects.

I not only gained knowledge during my assignment, but also

increased my network of experts within the Company. It was a

privilege to work with the professionals that comprise P&CSD,

but also the overall Engineering Services of the Company.

Roy A. Debellefeuille

“The wealth of

knowledge in

P&CSD far

surpassed my

expectations,

this department

truly has

talented

individuals.”


Answer to last Quiz Ibrahim M. Orainy from the Marine Department is the winner of the last P&CSD News Letter Quiz. His entry was randomly selected

from among four correct answers submitted.

The question asked whether a process operating in a cycle could produce a net positive amount of work by applying energy to a fluid

and then extracting more energy than had been put in and repeating this in a cycle.

This violates the first and second laws of thermodynamics and therefore any claim to have invented a process to do this is impossible.

The Quiz Master

Alt

raik

i P. P

ress

–F

ax:

8471

412

“Not all innovation is technology; yet technology is aresult of innovation. Both must produce tangible results. Justlook around yourself and imagine the vast number of prod-ucts and their manufacturing processes that transform one ora multitude of raw materials into a very different, useful prod-ucts.

Either the end or the intermediate products, or theirproduction steps are likely the subject of a ‘patent’ at some-time in their life span. To secure a patent, an inventor mustprove that the invention is not only novel, reproducible anduseful, but it is also not obvious to a person skilled in theunderstanding of all related prior knowledge (published,patented or practiced). The distinct ‘unobviousness’ require-ment places an inventor on a higher plateau than securinga PhD… hence the personal satisfaction of achievement andrecognition.

Inventing is easy; but it requires self-confidence anddiscipline, true willingness to learn and respect others’ knowl-edge, and an intense curiosity for in-depth understanding ofthe problem before seeking a solution.

Quote of the issue

On Innovation & Technology…

Inv. Yuv R. Mehra, LPE, P&CSD … holder of 28 USPatents related to processing of natural gas,refining and petrochemicals & polymers. About40% of Mehra’s patents are in commercial use inthree segments of the hydrocarbon processingindustry, including Saudi Aramco.

pcsd newsletter-special edition-2007

Technology

long term strategy

sun certified programmer

luay al awami

king saud university

ngl fractionation trains

basket impeller column

dhahran saudi arabia

ieee professional societies