lessons learned as o

Sl no. Code Lesson Title Job Code Project Discipline Moderator Lesson Description Recommendations Vivek's comments

557 LL-01364 JI-2002A EPS Majnoon Process Nagarajan N ok

553 444 JI-183 Process ok

552 446 JI-183 Process

551 457 Process

550 471 Moisture Analysers. Process Moisture analysers should be carefully selected for the product stream they are intended to be used on. Selection guide needs to be prepared.

546 5188 JI-196 Process Kirti Jain

544 5213 Pump NPSH JI 193 ASAB FFD Process Kirti Jain

543 5212 JI 193 ASAB FFD Process Kirti Jain ok

542 5211 Pump Shut Off JI 193 ASAB FFD Process Kirti Jain

532 5217 Line Numbering JI 193 ASAB FFD Process Kirti Jain


530 5215 Suction nozzle size JI 193 ASAB FFD Process Kirti Jain ok

Consolidated list of Lessons Learnt from BMS - As on 29/07/2011

CMMS Involvement for Tagging Philosophy

As tagging methodology and the tag structure has impact in client CMMS systems while implementing Asset Management, it is suggested that CMMS team be involved in the initial review as well ( say IFR stage). CMMS team is also to be kept in the loop on the Asset Tagging philosophy document circulation during initial stage. According to the client requirement, a tag for an equipment should be same irrespective of whether it is P&ID, SLD or Vendor document, which enables client to have the complete track in their CMMS systems. In Shell Majnoon (JI 2002) CMMS was involved during IFD stage for reviewing the tagging structure and philosophy, and has attracted some comments for correcting the tagging structure in all the disciplines. This issue is under review by CMMS & Project and may cause re-works for the disciplines to meet the tagging standard of the Client. Example: GTG fuel gas compressor was tagged as CP000-51-K-001 and used the same in all the documents. CMMS has requested to change this tag as CP000-51-A-001 (A instead of K), the reason being that all the accessories of the Compressor package can be included under A. Such comments during IFD or IFC stage necessitated the revision of tagging structure in Vendor documents and hence delay in compliance

It is recommended to involve CMMS Group at an early stage as appropriate, in applicable Projects, to finalise the Tag No. structure suitable for both Disciplines (Process & CMMS).

Dehydration units/ DRIZO Units.

Karachaganak FEED

Lorraine Fitzwater

It has been identified on more than 1 project that hydrocarbon carryover can be a problem with DRIZO units.

Recommendations from Operators and 1 large scale Project has identified that hydrocarbon skimmer should be installed to reduce the effects of hydrocarbon carryover.

Water carryover from upstream separation to

Splitter/Fractio

Karachaganak FEED

Lorraine Fitzwater

It has been identified from a recent project that water accumulation occurred in a downstream fractionators / Splitters as no water draw off facility existed. The water had to be drained manually through a dedicated connection on a Condensate Splitter Reflux Drum which was not the best or most reliable solution to the problem.

Water draw facilities should be provided where feed streams contain water and where simulations show water may accumulate.

Water accumulation occurs in columns like De-Ethanizers, Phenomenon so happens that the Water condensation happens before vapor reaches the column top, and condensed water re-vaporizes before hitting column bottom. As a result, the water accumulates in the column.Due to this phenomenon, simulation would not converge or converge erroneously.

Remedy :1. Provide water draw off few trays below the top tray.2. Phenomenon can be predicted by checking the water partial pressure versus operating temperature at column top & bottom.3. Simulations would sometimes require to be run on dry basis to converge.

Damaged coating due to cleaning

during shut down

Lorraine Fitzwater

Vessels that are internally coated have coating specification in accordance with the design operating temperature. During shut down the vessels are cleaned and purged with high temperature steam that may well exceed the vessel design temperature. This is resulting in damaging the internal coating. This may apply also to other equipments

Internal coating characteristics should be specified as a minimum to be compatible with the maximum foreseen temperature of the steam cleaning and purging.

Specifying Steam out conditions in equipment datasheet is a norm, and should take care of this issue. Process Engineer to ensure incorporation of the steam out conditions.

Lorraine Fitzwater

A recent project using MAs on glyco-dehydration units outlet streams failed to select appropriate and reliable analysers.

Kauther Depletion

Compression

In Kauther DC project we have inlet separators (SM type), Suction scrubbers (SMSM type) and Wet condensate drum (Horizontal SM type). While confirming adequacy of shell courses to vendor following issues were faced:Vessel Height/Length (High pressure vessel)Vessel dimensions (height and diameter) has been determined based on Shell DEP Criteria (such as sufficient residence time) and level settings are accordingly was decided by process. Instrument Engineering requirement/guideline to provide adequate rangebility was not aware to process. While finalizing the location of nozzle on the vessel to meet the rangebility requirement, it was fouling with the weldline. Level setting was required to be adjusted in order to meet the instrument requirement and at the same time does not deviate the process requirement.As the adequate margin was considered in the residence time the change in level setting did not resulted in deviation of process requirement.

) It is recommended that High pressure vessel process data sheet are sent for IDC to Mech and Instrument to confirm the level settings from Mech and Instrument design point of view 2) If project schedule allows keep hold on dimension of the vessel (height/length of vessel) or take adequate design steps/margin to cover the level settings requirement

Process level settings should never have to be revised based on weldlines. Following protocol needs to be followed to avoid any such issues :

1. Process specifies the instrument highset/lowest process levels.

2. Instrument dept decides the instrument ranges to fully cover the process specified levels, and represents them in Level sketches. These Level Sketches get reviewed by Mechanical to take care of all related subjects like Weldline.

3. Instrument nozzle elevations/locations hence get finalised first in Level sketches through mutual reviews, and then get fixed in the Vessel Mechanical datasheets.

Generally the NPSH is calculated from pump suction nozzle centre line. But when the actual impeller centre line is differennt from suction nozzle centre line, then the avialable NPSH calculated earlier will be different and insuffient

Provide enough margin for the actual pump centre line. Provide a suitable note in the pump process data sheet, "The NPSHA is calculated from pump suction nozzle centre line". Mech to inform process in advance if the suction nozzle centerline is offcentered with pump centerline of the impeller

Please review the suggested note & recommendation.

NPSH Calculations are always performed wrt Pump Centreline (which may be the Impeller Centreline). Process calculations should not correlate or refer NPSH calculations with suction Nozzle.

Hence, feedback required from Mechanical is "Pump centreline elevation", for Process to verify that the pump centreline elevation used in original calculations are not exceeded.

Tender Bulletin Mark-ups from

other disciplines

As per Tender Bulletin, manual isolation valves high pressure gas service (900# and above)shall be thruconduit gate valves instead of ball valve as shown in the P & ID.

Technical/Tender Bulletin requirements which impacts the P & ID or other deliverables for other disciplines needs to be well by respective originating discipline at the begining of the project.

The on plot piping design is confirmed based on the calculated pump shut off pressure. But the vendor information varies to large extent leading to change of piping design

During Fluid List preapration/piping specification finalization, Process to ensure sufficient margins are available between shut-off pressure and piping design pressure for a selected piping class. For borderline cases select higher pipeclass rating for discharge system. Pump Design Guide to include above requirement suitably

Pump datasheet should clearly specify that the head rise at shutoff should not exceed XXX % of the head at normal flow, where XXX is typically 120% for fixed speed motors, 138% for variable speed, or as defined in contract.

Piping design pressures should also be fixed & retained based on above. Note that most contracts do not anyway allow any reductions comnpared to contract specifications.

In most cases, Mechanical would be able to procure pump as per the specification, and thus not causing any rework to any discipline. Mechanical would come back with any deviations.

The same line number was used even when part of the line had a different pipe class (rating), which created confusion at site for setting up test packs, as well as for specifying the extent of non-destructive examination of the welds for two different pipe class.

Line numbers shall be associated with unique pipe class. Whenever the pipe lcass (spec) changes, the line shall be allotted a different unique line number. Also in case if the design condition differs but the pipe class remains same (e.g. Compressor Settle out case), then also separate line number should be given.

Kindly review approach. Changing line number at every change in spec, would increase the number of piping isometrics. And, it'll lead to non-squential numbers coming on the same line.

Chimney Tray - TEG Contactor

Insufficient over hung of the chimney cap leads to TEG leakage through the gap between chimney and chimney hat.

Overhung of Chimney Tray should be sufficiently large to avoid liquid leakage in to the sump. Over-hung cap gap ratio (Cap over hunf to gap) of 0.6 is recommended to avoid such problem. Mech to include above requirement in Vendor drawing review as part of the checklist and consult process if required.

Post Order of large capacity pump, the vendor information received indicates that the nozzle sizes are 2 or 3 size lower than line size mainly due to stringent requirment on pump suction line velocity criteria stated by customer. This reduction will increase the suction pressure loss and lower the pump NPSHA.

Pump checklist to include to verify following: 1) Take reducer Le/D based on 2 size reduction in reducer at pump suction nozzle for higher capacity pump 2) Re-verify the pump NPSHA based on the ordered pump suction nozzle



516 1062 JI-195 Process ok, unless project specs dicate FB to be used.

515 1063 JI-195 Process

514 1061 JI-195 Process ok. Spreadhsset to carry note.

513 1060 JI-195 Process

512 1059 JI-195 Process

511 1057 JI-195 Process OK. Additionally, we need to have a design guide for pumps.

510 1056 JI-195 Process

509 1058 JI-195 Process

506 1052 JI-195 Process


504 1054 JI-195 Process

503 1055 JI-195 Process

502 833 JI 176 T3 Process ok

501 1049 JI-190 Process

Strainer Pressure Drop in the pump

suction line

Pump suction strainer pressure loss is generally considered 0.07 bar as per the guidelines. However for larger capacity pump (above 500 m3/hr) the suction strainer pressure drop could limit the sizing and pressure drop increases above the specified value.

1) Preliminary inforamtion from vendor needs to be obtained to give a realistic suction pressure drop for estimation of NPSHA 2) For higher capacity pumps (> 500 m3/h), the allowable pressure drop accross the strainer shall be considered as 0.1 bar for NPSHA calculation purpose. This needs to be included in the checklist. 3) Specify the pressure drop across the strainer in the pump calculation sheet instead of estimating it using L/D ratio. Modify the eBMS calculation sheet.

Use of reduced bore on-off valves on blowdown lines

Elmerk project

Lakshmi Venkatesh

Full bore on-off valves were used on blowdown lines as per client philosophy and usual practice. However, client challenged the same since ROs are required and used on these lines anyway to substantially drop the pressure and so using full bore valves to reduce the pressure drop is not called for.

On-off valves on blowdown lines need not be full bore valves as usually followed in several projects. Reduced bore valves should be used, since these lines anyway include ROs to reduce the pressure and so pressure drop across the on-off valve is not a concern.

Effective coefficient of discharge (Kd) for relief valves

Elmerk project

Lakshmi Venkatesh

The relief valves were sized using coefficient of discharge (Kd) as 0.975 as per API 520. However, the vendor offers indicated lower values of Kd (0.875) requiring increase in size of RVs in some cases.

During initial/ preliminary sizing calculations of PSVs, more conservative value of Kd (effective coefficient of discharge) should be used than 0.975 suggested by API 520, to avoid significant size changes at a later date.

Process should use PSV sizes as provided through Instrumentation dept's internal calculations using Instrucal or InTools or Vendor programs. Process calcns are not as accurate due to Kb.

Flare KODs (horizontal) length

Elmerk project

Lakshmi Venkatesh

Flare KOD lengths were calculated using spreadsheet ˜Flare KOD sizing. This spreadsheet considers tan to tan length as separation length. However, it was later pointed out that the drum portion upstream of inlet nozzle and downstream of outlet nozzles is not available for separation and so tan to tan length had to be increased accordingly.

While sizing flare KODs using eBMS spreadsheet, it is to be recognized that drum portion upstream of inlet nozzle and downstream of outlet nozzle is not available for separation. So, tan to tan vessel length has to be higher than separation length as per the nozzlesâ€™ diameters and locations.

Line list data for flare headers/ sub-

headers/ lines

Elmerk project

Lakshmi Venkatesh

The process data for flare system lines was not appropriately populated. This resulted in several queries from piping/ stress groups subsequently requiring several revisions. The main errors/ flaws were as follows: 1) Maximum pressures and temperatures were specified based on independent relieving scenarios, rather than "coincident" operating conditions (maximum temperature corresponding to one scenario and maximum pressure corresponding to a different relieving scenario). This resulted in design conditions outside PMS limits. 2) Maximum fluid density was specified based on occasional release of liquids, which is not continuous. This resulted in difficulties in structures' design/ load calculations.

The process data for various lines and headers in flare system needs to be specified carefully, considering coincident operating conditions during various relieving scenarios, rather than specifying maximum conditions of pressure and temperature from separate relieving scenarios. Appropriate notes should be included to clarify the same. Similarly, the operating density should be specified on normal purge gas flow and any high densities occurring due to occasional liquid relief should be covered by notes.

Relief temperatures should not be entered as design temperatures, but rather as short term excursions.

Process data for instruments

Elmerk project

Lakshmi Venkatesh

There was no clarity on methodology/ means of providing process data and the data to be provided for various instruments to Instrumentation department. This resulted in confusion and repetition of work for process to issue the same data in PDS initially as well as in Intools subsequently as well as revisiting instrument data sheets for additional data asked by Instruments subsequent to first/ initial submissions.

Information transfer/ workflow between process and instruments should be defined at the project commencement or in general for all projects. Similarly, the process data required (including units to be followed) and to be provided for every instrument needs to be agreed, prior to data population/ compilation by process. E.g., format provided by Instruments for process data for on-off valves also included columns for operating pressures and temperatures, which is actually not necessary. Lot of time was wasted by process engineers to compile such information.

Very important activity. To be discussed and finalised.

Providing data through "Process datasheets" allows revision control, checking control and quality control.

NPSH for centrifugal and

vertical can pumps

Elmerk project

Lakshmi Venkatesh

While calculating and specifying NPSH available for pumps at initial engineering and enquiry stage, values of approx. 4-5 m and 0 m at grade were considered to be adequate for centrifugal and vertical pumps, respectively. However, during offers' evaluation, it was noted that some centrifugal pumps require higher NPSH. Similarly, in case of vertical can pumps, 0 NPSH is adequate at pump suction, and so the NPSH at grade needs to be higher if can pump suction is above grade level. These higher NPSH requirements identified at a late stage of engineering resulted in significant modifications in terms of suction equipment elevations/ foundations, suction piping sizing and routing etc.

NPSH requirements and availability for pumps need to be carefully looked at during initial engineering and calculations/ specifications. This can be done in consultation with rotary group as well using previous project data and/ or vendor literature for similar pumps. The pump datasheet should be sent to the rotary group for IDC for ensuring appropriate NPSH requirements to avoid changes after receipt of vendor offers. Adequate design margins should also be considered.

Equipment elevations

Elmerk project

Lakshmi Venkatesh

Initial issues of P& IDs/ datasheets indicated some equipment located at high elevations, without appropriate justification (e.g. Stabiliser Side Draw Drum, Oil/ Condensate Re-run Flash Drum). These were challenged by Projects due to structure/ loading difficulties by Piping/ Civil and then had to be relocated to grade level, since process requirements did not justify location at higher elevations.

Equipment elevations impact Piping/ Civil structures 'design and project costs and schedules significantly. Therefore, equipment elevations needs to be determined carefully and high elevations should be avoided unless required from process considerations. This aspect needs to be considered from first issue of P&IDs/ datasheets, to avoid engineering impact for other disciplines at a late stage.

OK. At the same time, contracts generally do not allow any reduction compared to ITT.

Line list/ Line numbering

Elmerk project

Lakshmi Venkatesh

Some lines required change in design pressure and/ or included a design pressure break along the line, though the line number was not changed (due to same piping class). Two different design pressures and test pressures were specified for such lines in the line list. Also, two lines were connected without any isolation valves/ break flanges, but with different design pressures. The above required several changes in line numbering to suit test packs for lines hydro testing.

Separate line numbers need to be used, whenever design pressure (and so corresponding test pressure) changes along the line, even if the pipe class is same. Similarly, the design pressure and test pressure breaks must be at valve and/ or flanged connection to allow hydro testing of relevant sections at different pressures.

Line numbering for every change in design pressure too, would lead to too many line nos and rework at later stage in project. To be reviewed.

Height of vertical tanks

Elmerk project

Lakshmi Venkatesh

Height of vertical storage tanks was calculated and specified based on recommended distance below the pump suction nozzle and above HHLL (besides hold-up and response time for alarms/ trips), as per process spreadsheet for tank capacity check . However, mechanical later advised that these distances are not adequate from mechanical construction considerations in some cases. Since tank procurement/ fabrication was at advance stage then, it was not possible to change tank height and this resulted in some compromise in process hold-up and/ or response time between normal and/ or trip levels.

After calculating height of vertical tanks as per tank capacity check spreadsheet, mechanical confirmation should be sought on adequacy of distance below suction nozzle and above HHLL, prior to PDS issue/ design finalisation. To be included in the relevant eBMS checklists/ guidelines.

Process should use Table 5-6a of API-650, to calculate height between tank bottom to centre of pump suction nozzle.

Consideration of gas blow-by case for flare system

design

Elmerk project

Lakshmi Venkatesh

Though a gas blow-by case was applicable for one of the flares, it was not considered for the flare design considering that blow-by will be prevented by instrumentation (2oo3 LL level trip) acting as ultimate safeguard. However, this was not acceptable to client requiring major change to flare capacity at late engineering stage.

Gas blow-by cases must be considered for flare system design and should not be ignored/ disregarded based on instrumentation acting as ultimate protection, unless supported by SIL determination and validation and formal agreement with client. To be included in the relevant eBMS checklists/ guidelines.

Nozzlesâ€™ sizing for Flare KO Drums

Elmerk project

Lakshmi Venkatesh

During initial sizing of various Flare KO Drums for the project, the nozzles were sized using rho * V2criterion as per relevant standards for equipment sizing. This resulted in nozzles diameters larger than the sizes of connected lines. It was later advised that Flare KO Drum nozzles are typically line size nozzles (in absence of any criterion in API) and no rho * V2 limitations are applicable.

Flare KO Drum nozzles should have same size as that of connected inlet/ outlet lines. No rho*V2 criterion are applicable.

rho*V2 criteria generally applies only to self venting nozzles and nozzles in steam service.

Hot Oil Expansion Drum RV sizing

Elmerk project

Lakshmi Venkatesh

Relief Valve on Hot Oil Expansion Drum was not sized to take care of tube rupture in exchangers using hot oil (where applicable). This resulted in significant changes in relief valve sizing, Expansion Drum nozzle size and the flare system downstream of relief valve, due to substantially higher load.

During design of hot oil system, care should be taken to check applicability of exchangers tube rupture case while sizing Relief Valve on hot oil expansion drum. This can often be missed; since the exchangers are designed as per 10/13 rule, where necessary, and so do not require overpressure protection for tube rupture. However, the hot oil piping connected to these exchangers requires overpressure protection, which needs to be provided by the hot oil expansion drum relief valve. This is required even in the case appropriate penultimate IPF is provided i.e. PAHH in hot oil side of exchanger to close valves on inlet and outlet hot oil lines of the exchanger.

Every tube rupture case system needs to be evaluated to see if the tube ruture can lead to overpressurisation of the connected upstrea/downstream systems. Hence, this point is not specific applicability of exchangers tube rupture case to hot oil systems.For example, application of 10/13 rule is generally limited to the HX's nozzles, or further till the upstream/downstream valves, due to the availability of open path thereafter.

Changes in Hysis simulation file

Kashagan Tranche-3

Lakshmi Venkatesh

When changes were made in the simulation, no records were maintained to indicate what were the parameters, specifications revised since the last issue. In simulations, it is difficult to track such changes in the input data since the volume of information is very large. All changes in revisions to simulation files like change in feed conditions, equipment specifications, convergence criteria are to be recorded.

A register to be maintained to record the changes in simualtion file together with the reason for the changes. This is required for each revision of the simulation that leads to the issue of a new Heat and Mass balance.

Centrifugal Pump discharge flow

limiting

EBLA GAS PROJECT

Lakshmi Venkatesh

The centrifugal pumps used for transfer service had no throttling device or control valve in discharge line. This was typically for pumps in non-process service like closed drain drum pump, Flare KOD transfer pump. During initial start, the low pressure drop across piping / clean filter, low battery limit pressures resulted in high flow through the pump causing pump vibration.

Centrifugal Pump discharge line should be provided with throttling device in the form of control valve or globe valve to take care of strtup conditions when the actual pressure losses in the system are likely to be much lower than the design values. Globe valve may be provided for non-critical services like closed / open drain pumps.

Foundation / piping need to be designed properly to handle vibration. Such pumps are typcially already designed for open discharge. Provision of throttling device, when not required per contract, would add to our cost especially when the high valve size would require MOVs.



495 833 JI 176 T3 Process Lakshmi Venkatesh ok

494 1049 JI-190 Process Lakshmi Venkatesh (Repeated ! Same as S.No 501)

493 1047 JI-190 Process Lakshmi Venkatesh Repeated. Same as S.No. 500

323 832 JI 176 T3 Process Lakshmi Venkatesh OK. General point.

322 830 JI 176 T3 Process Lakshmi Venkatesh

321 829 JI-190 Process Lakshmi Venkatesh ok

267 720 Fuel Gas generation PI-08017 BMS - ALGERIA Process G K.Bharani ok

235 5108 Pump capacities PI-7009 Process G K.Bharani These inputs would be provided by Mechanical-rotary during IDC.

146 242 JI 163 Dorood Process Robert Page ok. Excellent point.

55 3 Process Robert Page All valves in Drain lines of H2S service to be of full-bore type to avoid stagnant fluid. Full bore requirment to be taken indicated on the P&IDs. FB cannot prevent stagnant liquid. Stagnant portion needs to be traced.

54 6 Process Robert Page Venting of H2S from amine storage tank.

53 8 Ball Valve Process Robert Page Tight shut requirement for isolation. Tight shut off requirement to be indicated on P&ID. OK. General point.

52 10 Process Robert Page Liquid accumulates in sour service gas lines. ok

51 16 Level Instruments Process Robert Page Level Instruments - OK. What's the Process action ?

50 44 Piping Process Robert Page Spare pump must be warmed to fluid operating temperature before being put on line. OK. General point.

49 45 Piping Process Robert Page Liquids condense and carryover into compressor inlet. OK. General point.

48 46 Process Robert Page ok. Dilution is always provided for antifoam.

Process data for Pressure and Temperature transmitters

EBLA GAS PROJECT

Lakshmi Venkatesh

The process instrument data sheet for pressure/ temperature transmitters specified max/normal/min data for measured variable of instrument based on equipment max operating and design conditions. This resulted in wrong selection of instrument range since the values did not correspond to the operating requirements. For example : 1) The flare KO drum and closed drain drums are provided with heater to avoid freezing. The heater is switched on and off based on temperature transmitters located in the liquid phase to maintain the fluid just above water freezing temperature.In the instrument data sheet for temperature transmitters the maximum operating conditions of drum was specified instead of the temperature when the heater is required to switch on and off. The instrument had a range problem as controlling set point temperatures were in the very low range of the instrument and hence did not function as required. 2) Differential pressure transmitter, the max differential pressure specified was based on closed downstream valve (full upstream pressure) Instead of maximum differential when strainers / filters need to be changed. This resulted in problem for calibrating selected instrument alarm and trip points.

The instrument data sheet for transmitters should specify the required operating conditions and alarm values. This will ensure correct selection of range of instrument. The maximum values are used to specify the design conditions and not to set the instrument range.

Changes in Hysis simulation file

Kashagan Tranche-3

When changes were made in the simulation, no records were maintained to indicate what were the parameters, specifications revised since the last issue. In simulations, it is difficult to track such changes in the input data since the volume of information is very large. All changes in revisions to simulation files like change in feed conditions, equipment specifications, convergence criteria are to be recorded.

A register to be maintained to record the changes in simualtion file together with the reason for the changes. This is required for each revison of the simulation that leads to the issue of a new Heat and Mass balance.

Centrifugal Pump discharge flow

limiting

EBLA GAS PROJECT

The centrifugal pumps used for transfer service had no throttling device or control valve in discharge line. This was typically for pumps in non-process service like closed drain drum pump, Flare KOD transfer pump. During initial start, the low pressure drop across piping / clean filter, low battery limit pressures resulted in high flow through the pump causing pump vibration.

Centrifugal Pump discharge line should be provided with throttling device in the form of control valve or globe valve to take care of strtup conditions when the actual pressure losses in the system are likely to be much lower than the design values. Globe valve may be provided for non-critical services like closed / open drain pumps.

Process data for Pressure and Temperature transmitters

EBLA GAS PROJECT

The process instrument data sheet for pressure/ temperature transmitters specified max/normal/min data for measured variable of instrument based on equipment max operating and design conditions. This resulted in wrong selection of instrument range since the values did not correspond to the operating requirements. For example : 1) The flare KO drum and closed drain drums are provided with heater to avoid freezing. The heater is switched on and off based on temperature transmitters located in the liquid phase to maintain the fluid just above water freezing temperature. In the instrument data sheet for temperature transmitters the maximum operating conditions of drum was specified instead of the temperature when the heater is required to switch on and off. The instrument had a range problem as controlling set point temperatures were in the very low range of the instrument and hence did not function as required. 2) Differential pressure transmitter, the max differential pressure specified was based on closed downstream valve (full upstream pressure) instead of maximum differential when strainers / filters need to be changed. This resulted in problem for calibrating selected instrument alarm and trip points.

The instrument data sheet for transmitters should specify the required operating conditions and alarm values. This will ensure correct selection of range of instrument. The maximum values are used to specify the design conditions and not to set the instrument range.

Pipinng specification breaks

Kashagan Tranche-3

Some of the piping specification breaks have been provided at the tie in point of the connecting lines and there is no provision to isolate them. In the absence of isolation facility at specification break, hydrostatic test of the lines at their respective test pressure is not possible.

Line and pipe specification breaks to be given where isolation of the lines is possible e.g. at spectacle blind, block valve, check valve.

Seperate HMB's for Regeneration system in Dehydration unit

Kashagan Tranche-3

In a molecular sieve gas dehydration unit where there is cyclic operation, the HMB of Dehydration unit was issued for only adsorption mode of operation and one regeneration mode (desorption). Hence the Process datasheet of some of the Regeneration circuit equipments could not be co-related with the HMB e.g. Regeneration gas cooler duty which was controlled by the heating mode of operation.

For a cyclic operation like molecular sieve dehydration, the HMB should indicate all modes of operation that set the equipment design e.g. Adsorption, heating, desorption, cooling modes of operation.

HMB is generated only for steady state operations. Transient operations to be covered via notes in the HMB.

Design pressure of tank equipped with

emergency vent

EBLA GAS PROJECT

The design pressure of storage tank equipped with emergency vent should not be less than 5 mbarg. This is so because most of the reputed vendors of emergency vent have a range of product starting from 5 mbarg as a minimum. In Ebla gas project we had a storage tank with design pressure of 3.5 mbarg which had to be revised to 5 mbarg to suit the setting of emeregcny vent.

The design pressure of storage tank equipped with emergency vent should not be less than 5 mbarg.

In this proposal all the gas generated from the CPF is sent for 2 stage flash gas compression and 3 stage injection gas compression before being injected in to a gas injection well, Part of gas at the second stage flas gas compression outlet is taken for utiliy as Fuel gas for crude oil heaters,flare header purging and tank blanketing. The Fuel gas requirement for the fired heater based on vendor input during proposal was found to be very high from the ITT FEED total Fuel gas requirement. When we increased the Fuel gas from second stage compressor to cater to the Vendors requirement it was observed that the Gas Oil Ratio (GOR) was affected. Since, utilising more gas from the second stage flash gas compression , the liquid knock off is reduced in such a way the oil export capacity comes down to 13020 stb/d against the required 13200 stb/d, due to which the GOR has been considerably increased to 200 scf/bbl as aginst client specified guaranteed value of 186 scf/bbl.

Fuel gas consumption to all utilities to be reviewed during initial stage of the proposal to know if any deviations from the guarantee parameters (GOR) exists. A balance shall also be done after receipt of vendor details to verify the FEED specified requirements .

QAFCO Proposal

In QAFCO V proposal project we had a requirement of higher capacity pumps (18150 m3 /hr @ 7 barg) for cooling water and for the circulation rate we were in need of 10 pumps. We expected quotes and were unsuccessful as none of the approved vendors quoted for it. Later we found that the approved vendors range is around 13000 m3/hr to 14000m3/hr maximum from the vendors web pages. The vendor would have quoted if the capacity would have been in their range. We were not in a position to change the capacity (By increasing the no of pumps) as the P& ID and piping MTO were completed by then.

Care should be taken while choosing higher capacity pumps, keeping in mind the manufacturing range of the vendors,enabling to get a prompt quote from them and also avoiding changes in the Basic Engineering Documents at the last moment. We shall start working with available capacities and design the system,if we feel we are not getting any feedback from the respective vendors within the safe threshold period.

Diesel supply to Turbogenerators

Diesel fuel supply system catering to multiple Turbogenerators should be designed such that the supply pressure does not exceed the vendors maximum allowable limit even during upset conditions. Normally the maximum pressure limit for the turbo generators are well below the diesel transfer pump shut-off head, resulting in frequent generator shutdown due to high diesel supply pressure trip.

Individual pressure regulators should be provided for each turbogenerators on diesel supply system catering to multiple turbogenerators. This will prevent cascading effect of tripping of one turbo generators on other machines on the network.

Stagnant fluid in drain lines

H2S contaminated Amine to Storage tank

Lean amine booster pump in series with lean amine circulation pump to avoid pumping through amine storage tank to prevent H2S release from tank during column upset.

Free Draining/Condensation

Lines to be provided without pockets for sour service condensing lines or alternately Heat tracing with insulation for CS lines

Non-established gas / liquid interfaces,typicaly oil/gas in a process separator, shall be measured with differential pressure transmitter fitted with 2" minimum flush-design remote diaphragm seals with capillary tubing( taps shall be on the same section of the process separator)

Provide bypasses around check valves on spare pumps so they can be kept warm and ready to be put on line (Care must be taken that the pump does not rotate backwards when the bypass is open).

Either slope the compressor inlet line back to the inlet separator or trace and insulate compressor suction piping to prevent condensation of liquid with resultant carryover into the compressor. Tracing and insulating is preferred if compressor to be exposed to cold weather operation.

Antifoam/ Corrosion Inhibitor

Antifoam injection system was found to not be flowing antifoam into process due to high viscosity at low ambient temperature.

Care must be taken to prevent Antifoam/ Corrosion Inhibitor from becoming too viscous to pump. This can be done by either tracing and insulating the lines (care must be taken if the material is temperature sensitive) or by diluting the solution.

B83

prasad.sarma: 15-09.10


47 47 Process Robert Page OK. General point.

46 57 Valve type Process Robert Page Pump runs off end of curve due to lower than calculated head requirement and no throttling valve provided or pump be designed for EOC.

45 63 Check valve Process Robert Page Back flow through the minimum flow line to spare pump OK. General point.

44 67 Liquid entrainment Process Robert Page Liquid accumulation in separator outlet line and carry over into downstream equipment OK. General point.

43 74 Radiation Shield Process Robert Page Skin temperature of Claus reaction furnace becomes too cold and acid gas condenses behind refractory ok

42 64 Priming Process Robert Page Loss of containment of hydrocarbons during priming of pump Pump casing vent to be routed to suction vessel for hydrocarbon service. or to cbd / abd as is usually preferred.

41 65 Pipe class Process Robert Page Equipment isolation in high pressure service. Equipment in 600# and above piping service to have double isolation valve with bleed valve.

38 72 Expansion vessel Process Robert Page Location of Hot Oil Expansion vessel Hot oil expansion vessel to be located at high point in system

37 73 Pump Seals Process Robert Page Pump Seal failure on start up in hot service. Follow advise from Mechanical-Rotary.

36 80 Local Panel Process Robert Page Local Panel Ignition panel for reaction burner / incinerator not to be located in front of burner ok

35 82 Free draining Process Robert Page Free draining of condensate from re heaters is a must. Thermodynamic or bimetallic traps should not be used piping standard

26 83 Piping break flange Process Robert Page Piping break flange Requirement of break flange spool to be identified on P&ID ok

25 85 Train isolation Process Robert Page Train isolation not necessarily.

24 115 Flow measurement Process Robert Page Location of flow measurement devices Provide Flow measurement at compressor discharge rather than suction. OK. General point.

23 116 Compressor Piping Process Robert Page Compressor Piping was sloped towards compressor resulting in liquid carry over into the compressor OK. General point.

22 118 FG KO Drums Process Robert Page Possible carryover of hydrocarbon liquids into fired equipment when operating with saturated fuel gas and thereafter to be traced.

21 121 Process Robert Page Oil skimming of Rich Amine OK. General point.

9 88 Sulfur Pit sealing Process Robert Page Water sepage into the Sulfur Pit Ensure proper external/internal sealing of sulfur pit to prevent water seepage ok

8 90 Valve type Process Robert Page Valve selection in sulfur service Steam Jacketed, Full bore plug valves are to be used for all liquid sulfur services ok

7 91 Sampling valve Process Robert Page Sampling valve location Strahman valve to be located at 45? angle or at elbow. Not sure if Process needs to mention this in P&ID.

6 111 Hot gas by pass Process Robert Page Check the requirement of hot gas bypass in the initial stages of compressor selection. Location of HGBV (Hot gas bypass valve) shall be as close as possible to compressor discharge. ok

5 112 Process Robert Page Incorrect Antisurge Valve location can lead to compressor damage ok

4 114 Air Cooler Out Process Robert Page Provide Free draining of discharge air cooler piping OK. General point.

3 113 Check valve Process Robert Page Conventional check valve slams closed on compressor discharge Use Non slam type check valve at compressor discharge ok. Add note in P&ID.

2 120 Process Robert Page OK. General point.

1 123 Control Valves Process Robert Page

Air Cooled Exchangers

The bottom row of tubes in air cooled exchangers can freeze when exposed to cold air temperatures during winter operation in cold climates. This is especially a problem at turndown conditions

Air coolers in cold climates should be provided witha means of warming the inlet air such as steam coils or warm air recirculation.

Ensure valve designed for throttling such as globe valve or control valve is provided in every pump discharge.

If common minimum flow recirculation line is applied, check valve to be provided for each pump minimum flow line

Separator gas outlet lines to be sloped back to separator if it is critical that liquid is not carried into downstream equipment. If it is not possible to slope the line it is to be provided with suitable liquid carry over drain points either manual or automatic depending on the criticality of the drain requirement.

Thermal shroud for reaction furnace to be suitably vented with adjustable damper to control temperature. No insulation to be provided on shield

Please review. For example, we wouldn't do this for H2 service. Bleeds are not preferred from safety. Better is double block & blind.

At highest point. Or it may be blanketed / pressured in which case it can be low. Part of design.

Provide warm up lines for the seal flush system to prevent a surge of cold oil going through the seal on start up and the subsequent failure of the seal.

If two trains are applied with common incinerator the train isolation valve to be at the highest point with free draining on either side. This is to be noted on P&ID.

Compressor suction piping is to be shown on the P&ID as sloped towards the KO drum .If not possible, a boot is to be provided near the compressor for draining condensate. Investigate the requirement of heat tracing and insulation

Individual fuel gas KO drum or boot for each unit to be provided for knocking off condensate in fuel gas before the gas reaches the consumers (Turbines, Heater, Tank blanketing)

Oil skimming of Rich Amine

Provide oil skimming devices where oil is likely to collect, i.e. in the rich amine flash drum and the regenerator overhead drum.

Antisurge Valve location

Anti-surge valve in the compressor loop shall be located at high point in the discharge header. Tap off of the anti-surge line shall be from top of pipe.

Indicate "No Pockets" on P&ID for air cooler outlet line when there may be liquids present in the line.

Rich Amine Level Control Valve

Rich amine flashes across the level control valve resulting in two phase flow in the line to the regenerator and possible vibration of the downstrean line.

The level control valve shall be located at suitable platform elevation as close as possible to regenerator inlet nozzle. If this is not possible or desirable, the line downstream the control valve should be noted as two phase flow on the P&ID to alert piping to provide additional pipe support.

Control Valves - CORRECTIVE MEASURES/LESSONS LEARNED - Control Valves are generally located at grade but this must be carefully assessed for vapor service where if the valve is closed for an extended period of time a quantity of liquid may build up behind the valve and potentially damage piping/equipment if the valve is opened quickly.

Control valves in this service should either be provided with an automatic drainer if located at grade or designated as free draining on the P&ID to alert piping that the valve is to be located at a high point.

OK. Or heat trace, or ensure to open the valve slowly, or to use bleed/bypass prior to opening the valve.