siwes report chisom sam orji

8/10/2019 Siwes Report CHISOM SAM ORJI

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A TECHNICAL REPORT

ON

STUDENT INDUSTRIAL WORK EXPERIENCE SCHEME

(SIWES)

HELD AT

NIGERIA LIQUEFIED NATURAL GAS LIMITED

BONNY ISLAND, RIVERS STATE,

NIGERIA.

BY

ORJI SAM, CHISOM O.E.

MOUAU/04/4092

SUBMITTED TO

DEPARTMENT OF ELECTRICAL/ELECTRONIC ENGINEERING

COLLEGE OF ENGINEERING AND ENGINEERING

TECHNOLOLGY

MICHAEL OKPARA UNIVERSITY OF AGRICULTURE, UMUDIKE,

NIGERIA.

IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE AWARD OF

THE DEGREE OF BACHELOR OF ENGINEERING (B.ENG) IN

ELECTRICAL/ELECRTONIC ENGINEERING

JANUARY, 2009


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DEDICATION

This report is dedicated to the King Eternal, Immortal, Invincible; the Only Wise God. The

One who was and is and is to come. The Creator of the ends of the earth that faint not neither

is weary; there is no searching of His understanding. He gives power to the weak and to those

that have no might, He increases strength. From the rising of the sun, till the going down of

the same, the name of the Lord is to be praised. I love you Jesus!


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ACKNOWLEDGEMENT

I must first of all thank the Love of my life, Jehovah Effizi- My God of Special Effects, the

Almighty God for His Grace, Wisdom and Safety.

I want to also say a big thanks to the Conteam of NLNG, starting from the Executive Project

Manager, Engr Tony OgbuigweFNSChE, for giving me this rare privilege to have my

training in this multi-cultural world class company. Special thanks also go to the Chief

Engineer/Construction Manager, Mr Jan Schouten. I must also appreciate my wonderful Line

Head, Mr Frankenmolen Rob; and my explicit supervisors Mr Salihi Dawaki and Mr Henk

Heesemans who took me to the plant through out my period of attachment and you taught me

a lot, including how to be committed to the job. Thank you all for adding to my values! To

the entire NPP team, I say you are too much! I indeed enjoyed the team spirit that exists

among you, I can never forget NPP. I will not forget to mention the DBN staff that I worked

with; Messrs Emmason, Ralph, Peter Green, Jacob Solomon, Francis, etc. Thank u all for

your efforts in making me learn.

To my parents, Sir & Lady Sam Orji, JP God bless you real good for your contributions to

my life, ur advices and all your efforts, I love u and I say a big Thank you. To My Sisters

Ngozi and Miracle, my Brother- Prosper, i love you all. I must also thank my own

Thunderbolt Family not for getting room30.com: Nnana, John, Julius, Obaino, Frauk, Justin,

Pnd, 2Thunda, Katch, Oge, Mb, Jamo-D, Chima, Phil, Benz, Owen, McDon, T&T, and my


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beloved sisters: Chiluv, Jennifa, Stella, Okwy, Magi, Loveti, Uche, Aky, and others, thanks

for ur love, and also to my people in COR, JCCF, SUCF, MPNSC, I love you all and God

bless you too.

My lecturers, I want to seize this opportunity to say a very big thank you for your efforts.

To my colleagues in NPP; Samuel Amakiri, Ifeoluwalayomi Wole-Osho, Ichebadu Ejekwu,

Obubelebara Brown, Toye Adeyemo, Benjamin Ederiane, August Akpodiete, Rolian Green,

Priscilla Amachree, Muyiwa Tella and the guys from Lagos Office; Franklin Odoemena,

Emmanuel Okoro, Chioma Nwamah and Adebowale Adebiyi; I say the memories of being

with you guys will always be in my heart.

To everybody that has, in one way or the other, assisted in making my Industrial Training a

memorable one, I say thank you all and God bless you.


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TABLE OF CONTENTS

Title Page i

Dedication ii

Acknowledgement iii

Abstract iv

Table of Contents v

List of Tables vii

List of Figures vii

List of Abbreviations viii

CHAPTER ONE 1

1.0 INTRODUCTION 1

1.1 Background 1

1.2 Aims and Objectives 2

1.2.1 Aims 2

1.2.2 Objectives 2

1.3 About Nigeria Liquefied Natural Gas (Nigeria LNG) Limited 3

1.3.1 Location 4

1.3.2 Organizational Structure 4

1.3.3 Available Facilities 6


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1.3.4 Production Capacity 8

1.3.5 Staff Strength 9

CHAPTER TWO 10

2.0 WORK EXPERIENCE 10

2.1 Work Done 10

2.2 Experience Acquired 11

2.3 Challenges Faced 12

2.4 Solutions Proffered 13

2.5 Detailed Description of the Training Schedule 13

2.6 Tasks Performed 13

2.6.1 Valves 13

2.6.1.1 Classification of Valve 14

2.6.1.2 Globe Valve 15

2.6.1.3 Butterfly Valve 15

2.6.1.4 Gate Valve 16

2.6.1.5 Solenoid Valve 17

2.7 Fire & Gas Detection 18

2.7.1 Detection System 18

2.7.2 The Logic System 19

2.7.3 Plant Alarm Warning System 19

2.7.4 Alarm Presentation 20

2.7.5 Visual Alarm 20


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2.7.6 Flammable Gas 21

2.7.7 Open Path Gas Detectors 22

2.7.8 Fire Detectors 23

2.7.9 Manual Call Point 23

2.7.10 Automatic Fire Detectors 24

2.7.11 Smoke Detectors 25

2.8 Transmitters 25

2.8.1 Masoneilian Transmitters 25

2.8.2 Flow Rate 26

2.8.3 Flow Transmitters 26

2.8.4 Vortex Flow Transmitters 27

2.8.5 Pressure Transmitters 27

2.8.6 Pressure Transmitters Used in Nlng 29

CHAPTER THREE 30

3.0 Conclusion and Recommendations 30

3.1 Conclusion 30

3.2 Recommendations 31

References 32


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LIST OF FIGURES

Fig 1.2: NLNG Managing Director Division (MD) Corporate Organogram 4

Fig 1.3(a): NLNGPlusProject (NPP) Organogram. 5

Fig 1.4(b): NLNGPlusProject (NPP) Organogram. 5

Fig 1.1: Typical LNG Train 3

Fig 2:1 LNG Production 9

Fig 2.2: Vortex Valve 15

Fig 2.3: Butterfly Valve 16

Fig 2.4: Gate Valve 17

Fig 3.1: Point Gas Detector 22

Fig 3.2: Open Path Gas Detector 22

Fig 3.3: Manual Call Point 23

Fig 4.1: Vortex flow Transmitter 27

Fig 4.2: Hart Communicator 28

Fig.4.3: Rosemount Pressure Transmitter 29

LIST OF TABLES

ALARM PRESENTATION (Visual Alarm) 20


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LIST OF ABBREVIATIONS

CCRCentral Control Room.

GTSGas Transmission System

ISBIntegrated Supply base

ISBLInside Battery Limit

LNGLiquefied Natural Gas

LPGLiquefied Petroleum Gas

NLNGNigeria Liquefied Natural Gas

NPPNLNG Plus Project

OSBLOutside Battery Limit

PEFSProcess Engineering Flow Scheme

PPEPersonal Protective Equipment

FAR- Field Auxiliary Room

F & G- Fire and Gas (System)

MCP- Manual Call Point


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CHAPTER ONE

1.0 INTRODUCTION.

1.1 Background

Over the years, experts have been of the opinion that there is a yearning gap between the

learning acquired by graduates of Nigerian Universities and the skills repertoire required in

the workplace. Clearly, academic learning and theoretical knowledge alone would not

usually prepare an educated person for the world of work.

Highlights of the general deterioration in the quality of graduates from Nigerian Universities

in the recent past are open secrets. Employers believe that Nigerian graduates bring sufficient

theoretical knowledge to the job but that they generally lack hands-on or practical skills that

would make them productive and efficient. Consequently, a worker must not only be

knowledgeable but must also be versatile in the application of skills required to perform

defined jobs and work. This requirement is particularly crucial for graduates of science,

engineering and technology disciplines.

The great and spectacular advances and progress recorded by developed nations are primarily

and substantially attributable to the contributions of their scientific, engineering and

technological educational communities. They are the creators of change and innovation

which drive the world today. The community constitutes one of the most precious resources

and assets of any developing nation. Consequently, the capacity of Nigerian graduates to

innovate and create determines the extent of their potential contributions to the growing of

the economy and national development. However, the expected contributions can not be

made by graduates who are lacking in practical or hands-on skills repertoire.


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1.2 Aims and Objectives

1.2.1 Aims

1. To bridge the gap between university work and actual practice.

2. To enhance students contacts for later job placement.

3. To further expose students to the opportunities/potentials in their fields.

1.2.2 Objectives:

Specifically, the objectives of the Students Industrial Work Experience Scheme (SIWES) are

to:

1. Provide an avenue for students in the Nigerian Universities to acquire industrial skills and

experiences in their course of study;

2. Prepare students for the work situation they are likely to meet after graduation;

3. Expose students to work methods and techniques in handling equipment and machineries

that may not be available in the universities;

4. Provide students with an opportunity to apply their theoretical knowledge in real work

situation, thereby bridging the gap between university work and actual practice;

5. Make the transition from the university to the world of work easier, and thus, enhance

students contacts for later job placement; and

6. Enlist and strengthen employers involvement inthe entire educational process of

preparing university graduates for employment in industry.


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1.3 About Nigeria Liquefied Natural Gas (Nigeria LNG) Limited

Nigeria LNG Limited was incorporated on May 17, 1989 as a joint venture company, to

harness Nigeria's natural gas reserves, some of which are currently being flared. The

company purchases and liquefies Natural Gas for export to overseas markets. On 29th

November 1985; a Framework Agreement was signed following the formation of the LNG

Working Committee comprising the Nigerian Government, Shell Gas B.V, Elf and Agip. The

committee initiated the project and appointed Shell as Technical Adviser. The Nigerian

government is represented by the Nigerian National Petroleum Corporation, NNPC.

Fig 1.1: A Typical LNG Train


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1.3.1 Location

The Plant Complex is at Finima, Bonny Island, Rivers State, Federal Republic of Nigeria.

The head office is in Lagos and the liaison offices are in Abuja and London

1.3.2 Organizational Structure

The company has an organizational structure as shown in the organizational organograms

(with reference indicators) below. I was actually offered placement in the NLNG PlusProject

(NPP), a department under the Managing Director Division (MD). NPP is the project

construction team of NLNG and we are in charge of adding to the existing facilities (in terms

of structures) of the company. Our duty is to build the company. We are also involved in

community support and development programmes for our host communities.

Fig 1.2: NLNG Managing Director Division (MD) Corporate Organogram


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Fig 1.2(a): NLNG plusProject (NPP) Organogram.

Fig 1.4(b): NLNG PlusProject (NPP) Organogram.

NLNG Plus Project Department (1)

PA To Exec Proj Mgr

NPP/0

N. Lawson (C)

RET Manager

T6 ISBL/OSBL

HSE Coordinator

NPP/6

G. Stone

Project Services Coord.

NPP/4

S. Robertson

Project Interface Coord.

NPP/3

Francis Amego

Commissioning Manager

NPP/CM

R. Verburg

Snr. Mech. Engr

NPP/111

T. Ikpe

Mech. Engr

NPP/112

A. Ezekwe

Mech. Engr

NPP/113

Lead Mech. Engr

NPP/11

B. Starink

Civil Engr

NPP/121

I. Brown

Civil Engr

NPP/122

Civil Engr

NPP/123

Civil Engr

NPP/124

N. Mbata

Lead Civil Engr

NPP/12

AKL Sabry

Snr Electrical Engr

NPP/131

W. Couch

Electrical Engr

NPP/132

Electrical Engr

NPP/133

Head Electrical Engr

NPP/13

Snr. DCS Engineer

NPP/141

Instrument Engr

NPP/142

H. Heesemans

Instrument Engr

NPP/143

Instrument Engr

NPP/144

G. Kwajaffa

Lead Instrument Engr

NPP/14

R. Frankenmolen

Snr. Rotat Equip Engr

NPP/151

R. Hull

Rotating Equip Engr

NPP/152

Rotating Equip Engr

NPP/153

Head Rotating Equip Eng

NPP/15

S. Yusuf

Chief Engineer

NPP/1

Project Engineer

NPP/CO1

OSBL Coord

NPP/COA. Uwais

Const Mgr GTS 2/4 SC

NPP/SC

Construction Manager

NPP/C

A. van Bergen

QA Engineer

NPP/211

QA EngineerNPP/212

Y. Jegede (C)

Head Quality Assurance

NPP/21T. B. Aholu

Quality Control Engr

NPP/221

J. Van der Meer

Wielding Engr

NPP/222

H. de Wit

Field Inspector

NPP/223

B. Alabi

Field Inspector

NPP/224

Asst Field Inspector

NPP/225

A. Brown (C)

Head Quality Control

NPP/22

A. Tayo

QA/QC C oordinator

NPP/2

Executive Project Manager

NPP

A. U. Ogbuigwe

NLNG Plus Project Department (2)

CR Project Engr

NPP/311G. Olanrewaju (C)

CR Field EngrNPP/32

A. Allagoa

Project Relations Engr

NPP/31

Proj Interface EngrNPP/322

S. Jumbo (C)

Lead Proj Interface EngrNPP/32

Administrative Assistant

NPP/331

B. Biambo

Admin AsstNPP/338

G. Ezekiel (C)

Procurement Officer

NPP/335

J. Ngeneka (C)

Protocol/Liaison OfficerNPP/333

G. Uka (C)

Logistics/Office Admin

NPP/334

E. Somiari (C)

Protocol/Liaison Officer

NPP/336

J. Aguh (C)

Administrative Assistant

NPP/337

Senior Admin OfficeNPP/33

J. Okubor (C)

Project Interface CoordinatorNPP/3

F. Amego

Proj. Services Engr

NPP/411

Proj. Services Engr

NPP/412F. Tella

Asst Proj. Services Engr

NPP/413S. Adebimpe

Lead Proj/Contract Engr

NPP/41

T. Abana

Proj. Devt. Engr

NPP/42

Project Cost Cotroller

NPP/431O. Ewuyemi (C)

Project Cost Controller

NPP/432

Senior Cost Engr

NPP/43A. Akpuokwe

Asst Document Controller

NPP/441C. Oguji (C)


NPP/442


NPP/443C. Olodu (C)

Document Controller

NPP/44E. Fubara (C)

Proj. Services Coord.NPP/4

S. Robertson

Senior HSE Engr

NPP/611A. Dauda

Environmental EngrNPP/612

HSE EngineerNPP/613

W. Tom-George (C)

HSE EngineerNPP/614

F. Ezinwo (C)

HSE CoordinatorNPP/6

G. Stone

See

Comm & Start UpTeam

Commissioning ManagerNPP/CM

R. Verburg

Executive Project ManagerNPP

A. U. Ogbuigwe


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1.3.3 Available Facilities

The first structures built are called Base Project and it has a design capacity of 5.8 million

tons per annum of LNG and can deliver 7.15 bcm per annum to customers. In addition to

LNG, the Base Project produces 6,000 barrels of condensate per day. The Base Project

consists of the following:

Two train gas liquefaction plant.

A Gas Transmission System (GTS) passing through 110 communities for the supply

of natural gas to the plant via gas network.

Two LNG storage tanks with capacity of 84,200 cubic metres each.

Two condensate storage tanks with capacity of 36,000 cubic meters each.

Four Gas Turbine Power generators with a total capacity of 160 MWatts.

LNG export jetty.

Seven LNG vessels for Cost Insurance and Freight (CIF) deliveries to the LNG

Buyers.

Residential areas covering 2.08 square km.

Materials off-loading jetty.

The next project embarked upon was called Expansion Project. The Expansion Project

includes a third liquefaction train, LPG facilities - storage and a jetty. The Expansion Project

consists of:

A third LNG train of similar design to the existing two Base Project trains.

Modification of trains 1 and 2 to process 100% associated gas.


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A common fractionation plant to produce LPG.

LPG storage and loading facilities.

A third LNG storage tank.

Additional utilities and common facilities (electrical power, water, building, etc).

Two LNG vessels for CIF deliveries to the LNG buyers.

Total LNG plant capacity of the Base and Expansion Projects is 8.7 million tons per annum.

The next project was the Plus Project which includes two liquefaction trains (4th and 5th).

The two trains have a different design from the existing three in that they are cooled by air

while the first 3 trains are cooled by water. Therefore, no water cooling tower was built as

part of the Plus Project.

After the Plus Project came the Six Project divided into ISBL and OSBL. ISBL was awarded

to TSKJ. The Six Project (ISBL) provided the 6th NLNG liquefaction train. Train 6 design is

just a replica of that of Trains 4 and 5. No cooling tower was built as part of this train also

because it is air-cooled.

The on-going project is called NLNG OSBL SixProject, awarded to Entrepose Contracting

Delattre-Bezons Nigeria Limited. It is to provide additional LNG and LPG storage tanks

(LNG, Butane and Propane tanks) and another Condensate Stabilization Unit (CSU).


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In addition to the aforementioned, the company also has the following associated facilities:

Water Wells and other utilities.

The Gas Transmission System (GTS) which transports gas to the plant site from the

three supply points: Soku (SPDC), Obite (EPNL) and Obrikom (NAOC).

The Gas Transmission System (GTS) Node at Rumuji/Ubeta.

The ISB (Integrated Supply Base) at Port Harcourt.

1.3.4 Production Capacity.

The existing trains have a design capacity of over 17.4 million tons per annum of LNG and

can deliver 21.45 bcm of LPG per annum to customers. In addition to LNG, the trains

produce over 18,000 barrels of condensate per annum.


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Fig 2.1: LNG Production

1.3.5 Staff Strength.

The company has human asset of approximately 4,000 direct and contract staff including

secondees from the shareholder companies (i.e. Shell, Total and Agip).


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CHAPTER TWO

2.0 WORK EXPERIENCE.

2.1 Work Done.

The following is a shortlist of tasks and activities carried out during the programme:

Inspection of Installation of instruments at the Condensate Stabilization Unit (CSU).

Clearing of master punch list for instruments on top of propane tank.

Inspection of Installation of valves on top of propane tank.

Inspection of Installation of Transmitters on top of propane tank

Inspection of Junction boxes on top of propane tank.

Clearing of master punch list for instruments at integration area of propane tank.

Inspection of instrument name plate, wire tags, ends cap and cable tray cover

installations.

Inspection of fire alarm systems in propane tank area

Inspection of Junction boxes at integration area of propane tank.

Inspection of valves on top of butane tank

Inspection of installations of transmitters on top of butane tank

Clearing of master punch list for instruments on top of butane tank

Clearing of master punch list for instruments at integration area of butane tank

Inspection of Junction boxes on top of butane tank

Inspection of Junction boxes at integration area of butane tank

Inspection of fire alarm system in butane tank area.


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Inspection of gas and fire alarm panels and systems in butane tank area, FAR 18 and

SS 35

Inspection of slab Resistance Thermosistor Detector in propane and butane tanks

Inspection of underground cable name plates prior to backfilling at CSU

Inspection of name plates, cable tray cover and wire tags for instruments, cables and

wires at CSU and Tank areas

Continuity testing of the slab RTDs around the Propane and Butane tanks.

Inspection of air compressor and Junction boxes at the CSU

Information Security Training

Various safety trainings and inductions such as Health, Safety and Environment (HSE)

induction, Confined Space Entry induction and Nitrogen awareness training, Job

hazard analysis and Permit to work (safety) Trainings.

2.2 Experience Acquired.

The NLNG is a world class multi-cultural oil and gas company that has integrity, teamwork,

excellence and caring as her core values. The company instils this belief into the minds of her

workers and provide them with all the necessities of life for them to concentrate on their jobs

efficiently. The company has given me a world class experience as I have been exposed to

various ways of office practices, engineering management, construction site inspection, plant

operation, safety, working in accordance with procedures and specifications, division of

labour, client-contractor relationship, setting and meeting targets, human relationship,

teamwork, integrity, efficiency, productivity, observation, alertness etc. It was a great

opportunity to see some theories learnt in school being put into useful work


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2.3 Challenges Faced.

The programme was quite challenging, but was seen as a process of making and a kind of

build up to greatness. NPP is the construction department of the company so; I had to face all

the rigours of construction processes. The followings are the challenges:

1. Adaptation to work place environment (gas plant and construction site) as it was

totally different from the other environment I was used to.

2. Climbing very tall heights like Butane tank and Propane tank using stairs which

initially always led to body pains.

3. Adaptation to early hour resumption time (strictly 7.00 am).

4. Adaptation to working under sun for hours.

5. The challenge of adapting to working with the inconveniency of wearing the basic

PPE (e.g. safety shoes, hard hat, goggles, hand gloves, ear plugs, etc.).

6. The need to manoeuvre oneself into little spaces in-between pipelines to confirm

installation of items that can not be seen from afar.

7. The need to cope with some offensive smell when working in certain areas of the

plant.

8. Standing firmly on the slippery storage tanks tops of about 46 meters above ground

level was also a challenge.

9. I had to wait for a period of time for the company to provide me with an identity card

that will allow me entry into the live plant area.


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2.4 Solutions Proffered.

I had no choice other than to increase my proficiency through increased commitment. On

height climbing, I chose to be taking a lot of rest after work. So, I always stay indoors at

home after work. The entire members of staff of NPP also helped a lot, especially, the

cooperation I received from NPP Instrumentation Department.

2.5 Detailed Description of the Training Schedule.

For the major part of the period, I was with the NPP; I only visited the CCR and the plant

panel where the operators operate the plant with touch-screen technology to control/monitor

virtually all valves and other instruments, to store and load LNG and LPG, and to carry out

every other operation on the plant.

2.6 Tasks Performed.

2.6.1 VALVES

A valve is a control device that is used to modify the flow rate in a pipe. The modification could

be as a result of full restriction of passage to provide zero flow or no restriction to provide

maximum flow or modification between the two states. A typical valve consists of an actuator,

stem and valve body. Other additional parts include instrumentation and control devices such as

the positional (especially for control valve), and the proximity sensor, solenoid valve, pressure

regulator, etc.


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The valve body provides the path through which the flow can be modified. The actuator is the

source of motion, while the stem links the actuator to the valve body in other to transmit the

motion to the closure member. The positioner, when installed is used to provide a controlled

actuation of the valve. It also tells the position of the valve. The proximitor sensors are for valve

position signal transmission.

Different types of valves from different instrument manufacturers are used in the NLNG plant.

They include the Valtek control valve, the Masoneilan, Fisher, Joucomatic , Globe etc.

2.6.2

CLASSIFICATION OF VALVES

Valves are categorized according to the design style. The style can be grouped into the following:

1.

Type of stem motion- linear or rotary

2. Valve operation- air to close(ATC) or air to open (ATO)

3. Type of seat- single seat or double seat

4.

Shape of closure member- gate, equal percentage and linear valve

5. Application- antisurge, relief, trip, pressure control, level control valve etc

6. Others are- solenoid valve, check valve relief valve

2.6.3

GLOBE VALVES

This is the most common linear stem motion control valve. In globe valve, the closure member is

called a plug. The plug is guided by a large diameter port. It moves within the port to provide the

flow control orifice of the valve. Some designs have cage guided plugs in which openings in the

cage provides the flow orifice.


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The valve seat is the zone of contact between the moving plug and the stationary valve body. The

plug, the cage, the seat ring and associated seal are grouped and also called the trim of the valve.

When the plug closes against the seat, it closes the flow orifice thereby preventing the flow. On

the other way, if the actuator moves the plug away from the seat, the orifice opens and the fluid

flows accordingly.

Example of this type of valve used here in the plant is the Flowserve Valtek control valve as shown infig-----

2.6.4

BUTTERFLY VALVE

Another type of valve widely used in the plant is the butterfly valve. This is an example of the

rotary motion valve. They come in different sizes depending on the process pipeline they are to

be used. Like any type of valve, it could be manually or actuator driven. It also consists of the

actuator and the body components and the stem also. The body of the valve makes it different

Fig. 2.2 picture of FlowserveValtek Control valve

Fig. 2.2b Valtek control valve showing theinternals


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from other valve. It has a classic wafer body design which is clamped between the pipeline flange,

and a disc closure member which is offset from the shaft

2.6.5

GATE VALVE

The Gate Valve is a type of isolation valve normally used for ON/OFF application. Its peculiarity

is the manner which it operates. The closing member is a disc, also called the gate which moves

Perpendicular to the flow stream. The disc is moved up and down when actuated by a threaded

screw stem that is rotated to effect the disc movement.

Fi . 2.3 icture o Butter l valve


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The gate valve is used for ON/OFF control action because it provides a very tight shut off to

prevent any form of leakage. It is the most widely used valve in this application.

Additional sensitivity to over pressure conditions can be improved by adding an auxiliary

pressure relief valve (pilot) to the basic pressure relief valve. This combination is known as a pilot

operated pressure relief valve.

The safety valve is not different function wise to the normal relief valve. The only difference is

that the safety valve is designed to fully open or pop with only a small amount of pressure over

the rated limit.

2.6.6

SOLENOID VALVE

Solenoid valves are special types of valve. It is electrically powered unlike the conventional

pneumatically powered valves. It also has a port for pneumatic input and output. As the name

implies, it is solenoid operated. A solenoid is an electromagnet which will become magnetic

when current flows through it.

When sufficient electric current is supplied to the coil, an internal armature moves against

a spring to an extreme position this creates a clearance to either shut off or allow air flow

Fig. 2.4 Bodyof a Gate valveFig. 2.4b Schematicfor gate valve


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through the valve. Removal of the current source de-energizes the electromagnet and the

armature causes the spring to return to normal position thus blocking the flow of air.

Generally, solenoid valves are not used as stand alone valves. They are used with the

other valves (main valve) as valve control device to pressurize or vent actuator casing for

ON/OFF control valve application. It is also used in safety shutdown applications for

safeguarding systems.

2.7 FIRE AND GAS DETECTION SYSTEM

Due to the hazardous and critical nature of the LNG process, the protection of the

plant and associated facilities against any form of fire and gas hazard is given a very

high priority. An independent system is dedicated for this purpose. Negligence on the

protection of facilities against fire has cost many organizations, individuals, including

the government a great loss. The negative impact the aftermath that fire and gas

disasters bring is something not to be imagined. The experience from this section can

be applied in other organizations, government establishments and even our homes.

2.7.1 DETECTION SYSTEM

The function of the detection system is to promptly detect any hazardous condition

resulting due to fire and gas, and to also send control signals to other sub-systems for

required protective action. Appropriate flammable gas, smoke, heat, and fire detectors

are provided in strategic locations through out the plant for immediate detection of

specific hazard. Most of the detectors send signals of 4-20mA or 24volt or volt free


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contact signal input to the logic system. The field signal is connected to the logic

system by means of systems cable via the MDF cabinet.

2.7.2 THE LOGIC SYSTEM

The logic system receives input signals from the detection system and carries out

functions such as:

1. Selective alarm display initiation in the control room and the plant areas.

2. Shutdown of equipment and isolation of process units as appropriate GT shutdown,

fan and damper shutdown, isolation of electrical supplies in hazardous atmosphere etc.

3. Activation of fire fighting devices as specified e.g. spray systems, Co2 systems.

The logic system is implemented by means of dedicated redundant PLCs located in

the appropriate FARs.

2 .7.3 PLANT ALARM AND WARNING SYSTEM

According to their location, gas detector will initiate alarms and trip functions. Some

could be configures to be alarm only, alarm and trip, pre-alarm and trip.

Alarm audio visual devices such as horns, beacons, Sirens etc are provided in

strategic areas through out the plant and occupied building to alert plant personnel of

imminent danger. Gas alarm is accompanied with the flashing of a blue beacon. Fire

alarm, which is louder, is accompanied with the flashing of red beacon. In the event of

any fire alarm, all personnel on sight are expected to safely terminate whatever job

they are doing and go to designated muster points. They will remain there until the all

clear alarm is sound


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2.7.4 ALARM PRESENTATION

Alarms are presented in different ways in the plant. This depends on the location of

distress and also the cause of the alarm. Variation in alarm presentation helps for easy

identification of the cause. The tables below give summary of how alarms are

presented in the plant.

2.7.5 VISUAL ALARMS

Visual alarm presentation devices vary with location. However the colour codes are

still the same. In the central control room, on the fire and Gas semi graphic panel, the

alarm presentation is as follows:

Cause Visual alarm Audible alarm remark

Flammable gas blue light buzzer

Fire red light buzzer

System fault white light buzzer

Others Red buzzer

Note that in the event of any of these troubles, the buzzer will continue to sound until

the operator pushes the accept button to acknowledge the alarm.

In addition, a dedicated printer is provided in the central control room for recording of the

alarms and events related to the fire and gas system.

2.7.6 FLAMABLE GAS DETECTION

The fire triangle principle upholds that fire will occur if the following constituents are

available:


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1. flammable gas between its LEL and UEL

2. ignition source

3. sufficient oxygen to burn

The early detection of flammable gas leak is of vital importance in preventing explosions

or potentially hazardous conditions. Alarms for flammable gas detectors are set below the

lower explosion limit (LEL) of the gas so that it can be quickly dispersed before it

achieves the potential to cause fire.

In the NLNG processes, probable leak sources resulting in flammable gas clouds are not

limited to the seals of centrifugal process gas compressors, and pumps handling light

hydrocarbons. Gas detectors are also installed on the LNG loading Jetty, the storage tank

platform, and other gas associated facilities.

All detectors use two different wavelengths of signals, one that can be absorbed by the

gas (sample) and another one that cannot be absorbed by the gas (reference), so that

under gas free conditions both beams are affected by similar ambient changes such as

humidity or dust. Should gas be present, the sample beam is absorbed by the gas, the

reference beam remains unaffected and a differential output is obtained as a signal

warning indicating the presence of gas.

When a single IR source or emitter is housed together with the receiver, and a reflector or

mirror to send signal to the receiver, the detector is said to be a Point gas detector because

it can only analyze gas at one spot. Otherwise, it is called open path gas detector. This

eliminates the difference in the signal strength of the sample and reference sources.


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2.7.7 OPEN PATH GAS DETECTORS

These are installed around the perimeters of the LNG Process Trains, and above the

Regen Gas Coolers. The operating principle is similar to the Infra Red Point Detector.

Here the receiver is somewhat separated from the transmitter box. For the one use here,

maximum distance of separation is up to 120m away

Again, in the event of a hydrocarbon gas cloud passing between source and receiver, it

absorbs light proportionally equal to the concentration.

Fig. 3.1 Picture of Polytron IR Point gas detector Fig. 3.1b Schematic diagram of operation ofPolytron Infrared point gas detector

Fig. 3.2 Picture of Polytron IR open path gas detector


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The detector transmits a 4 to 20 mA signal to the F & G system. This corresponds to a 0

to 100% of the LEL.M of the gas. The signal range is 0 to 5LEL.M. However in NLNG,

alarm is set at 1LEL.M. An audible gas alarm is triggered from the F&G system when

this setting is reached.

2.7.8 FIRE DETECTORS

The detection of fire in its earliest stage of development cannot be overemphasized if

prevention of fire outbreak and attendant explosion is to be achieved.

In NLNG, two forms of fire detection are employed namely: manual fire alarm call points

and plastic tube automatic fire detection.

2.7.9 MANUAL CALL POINT (MCP)

Manual call points are break glass actuated switches which are located through out the

plant areas along the roads, escape routes, at higher risk

locations e.g. pump floors, manifold etc, and the exits of

buildings.

Here the appropriate action is/are initiated according to

the cause and effect matrix programmed in the PLCs.

Some manual call points especially those in buildings have capacity to be addressed. This

makes identification of distressed point easy from the fire panel in the building.

Manual call points in the plant initiate plant wide fire alarm. The alarm latches on the fire

and gas system until the glass is replaced.

Fig. 3.3 Picture of Manual Call Point


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2.7.10 AUTOMATIC FIRE DETECTOR

This is the major automatic fire detector system in the plant is the Fusible polyethylene

tubing. It used mostly on the equipments protected by automatic fixed water system or by

manually activated low expansion foam system. The equipments include hydrocarbon

pumps, expanders, compressors Storage tanks etc.

The fire detection works on a simple principle. Black fire retardant polyethylene tubing is

placed in close proximity to the fire prone parts of the protected equipment.

The start of the tube has a pressure regulator to fix the tube pressure to 2barg. Another

end is connected to a pressure switch which is set at 1.5barg.

In the event of fire, the tube will rupture at 100oc then the pressure switch will signal loss

of air pressure due to rupture, at 1.5barg.

The pressure switch contact (normally closed when healthy, opening on trip) are input

into the F&G system, where appropriate actions are initiated, according to the cause and

effect matrix of that unit.

Apart from the low foam system, this has only one tube arrangement, some other

equipments have a pair of fire tubes for protection. In the event of one failing, an alarm is

generated on control panel as system fault. Should both fail, then the On/Off Valve on

the fixed water system will open to spray extinguisher (if specified), fire alarms will be

initiated locally and in the control room. Fire pumps would also start automatically.


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2.7.11 SMOKE DETECTION

There is no fire without a smoke is a popular saying we often hear. Smoke detection is

essential because non explosion engendered fire like burns will usually generate smoke

for some time before the actual fire comes. For this reason, appropriate smoke detectors

are placed at strategic places for its detection. Three types of smoke detector are in use

here. They include:

-Combined Optical/heat type detectors

-Very early Warning type smoke detectors

-Ionization type smoke detectors.

2.8 TRANSMITTERS

2.8.1

MASONEILIAN DIGITAL LEVEL TRANSMITTERS

The masoneilian digital transmitter used here is the MODEL 12300 type. It is a displacer type of

level instrument, with high performance easy to set instrumentation. It is a 2-wire, loop powered,

and digital displacement level transmitter with HART communication module. It has a displacer

tube which is a narrow, long, closed cylinder. This tube is half submerged in the liquid at normal

level. The mass of the displacer is sufficiently large not to float and so the displacer will sink if it

is not attached to the measurement system. The displacer tube is linked via a torque arm to a

torque tube which transmits rotary motion through its torque rod to a magnet over a Hall Effect

Sensor.


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2.8.2

FLOW RATE MEASUREMENT

Flow rate of liquids and gases is very important in the process industry. Measurement of flow

indicates how much fluid is used or distributed in a process. Although flow measuring

instruments are not as common like the other process variable instruments, they are indispensable

in the process plant. Another less frequently used term is the volume flow, which is used to

describe the volume that flows per unit of time e.g. m3/s or dm3/min at a specified temperature

and pressure.

Volume flow rate, q = change in volume, m3/s

Change in time

Mass flow rate, W = q, expressed in Kg/s

Where = density of fluid

Flow instruments used in the plant include flow indicators and flow transmitters produced by

various instrument manufacturers.

Flow indicators are mainly for field indication purposes, having no control and alarming function.

The transmitters give continuous measurement in a standard 4 20mA electronic signal output

which can be transmitted to the FARs and CCR?

Flow transmitters or indicators can be installed online or inline. Inline installation requires fixing

the device on the same line as the process pipe. Online diverts the flow through another channel

for measurement.There are various principles of flow rate measurement. These include the

differential pressure flow meters, turbine flow meters, vortex-shedding flow meters, magnetic

flow meters, positive displacement sensors, ultrasonic flow meters etc. Examples are: the Khrone

and the Brook flow indicators.

2.8.3

FLOW TRANSMITTERS

Flow transmitters do not only measure the flow, it also converts the measured signal into a

standard electrical form, which is transmitted to process control stations for necessary


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information and action. Some of them have on site indications. An example of the flow

transmitter used in the plant is the vortex- shedding flow transmitter.

2.8.4

VORTEX FLOW TRANSMITTERS

These flow meters take advantage of vortex shedding, which occurs when a fluid flows

past a non streamlined object (a blunt body). The flow cannot follow the shape of the

object and separates from it, forming turbulent vortices or eddies at the objects side

surfaces. As the vortices move downstream, they grow in size and are eventually shed or

detach from the object. Shedding takes place alternately at either side of the object. The

resulting pulsations are sensed by a piezoelectric crystal. The rate or frequency of vortex

formation and shedding is directly proportional to the fluid volumetric flow rate.

2.8.5

PRESSURE TRANSMITTER

In the control of modern process plant, the transmitter is indispensable and indeed the

crown of process measuring instruments.

A pressure transmitter is an instrument which measures the pressure of a process converts

it into a standard electrical signal which could be read on site and can be transmitted over

a distance to for example a receiver in the Field auxiliary room (FAR) or the control room.

Fig. 4.1 picture of Vortex flow

transmitter


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A typical transmitter consists of a sensor, converter and amplifier unit. Intelligent ones

are microprocessor based and include a communication unit.

In addition to the electronic transmitters of the two-wire type there are also transmitters

that use the four-wire system. With this type two wires are used for connecting to the

external supply.

The other two wires are used for the output signal of 0 to 20 mA. With the four-wire system

it is possible to use 0 to 20 mA as the auxiliary energy required for the transmitter is not

obtained from the output signal. However, most of the transmitters used in NLNG are the

two wire type. Modern transmitters are microprocessor based and include a communication

unit. They are known as smart or intelligent transmitters because they can communicate and

be communicated to. The HART communicator is used to communicate with the device.

Fig 4.2 A pressure transmitter connected to a HART communicatorFig. 4.2b Picture of HART communicator


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2.8.6

PRESSURE TRANSMITTERS USED IN NLNG

Majority of the pressure transmitters used in NLNG are of two manufacturers. These are

the ABB transmitter and the more popular ROSEMOUNT transmitters. They all work on

the basic principle of transmitter above, and are intelligent devices HART compliant.

They work on the capacitance pressure sensor principle. The two diaphragms are filled

with silica oil. It is designed to work as a differential type, having the low (-) and the high

(+) pressure side. Rosemount transmitters are classified in ranges three (3) to nine (9).

This defines the maximal measurable range of the transmitter.

The ABB transmitter comes in both differential type and the gauge type

Fig. 4.3 pictures of different models of

Rosemount Pressure Transmitter


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CHAPTER THREE

3.0 CONCLUSION AND RECOMMENDATIONS

3.1 Conclusion

I have drawnthe following conclusions from my SIWES programme:

1. The SIWES programme provided a great opportunity for me to get the necessary practical

experience needed while still in school. This exposure to practical work has helped me

develop a better appreciation of what is being taught in school. In the engineering discipline,

the benefits of such practical experience are numerous. Theoretical information became real

to me as I saw, with my own eyes, the application(s) of what I had been taught. Seeing the

practical work also ensures that I will not forget what I have been taught.

2. However, the benefits of any industrial training can only be obtained if the trainee is

willing and inquisitive enough to learn. Without an inquisitive attitude, a trainee would

simply look at various works being carried out, without being able to understand or link them

with previously acquired knowledge.

3.My industrial training at NLNGs Construction Office (NPP) resulted in me, being able to

see some huge and uncommon (in this part of the world) engineering construction works and

equipments. I was also fortunate to have access to engineering codes of practice, procedures,

manuals, textbooks and drawings, which I studied to find out more about the various

activities being carried out at the construction site and plant complex.


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4.The industrial training programme was very beneficial, and active participation should be

encouraged. Various engineering firms should also be willing to assist the universities in

training students by allowing the students to obtain practical experience with them.

3.2 Recommendations

I hereby make the following recommendations:

1.Having undergone my industrial training in a world class multi-cultural company like the

Nigeria LNG Limited, I discovered that six months is actually not enough time for a student

to bridge the gap existing between theory and practice of engineering and technology. It is

not enough time for students to get acquainted to professional work methods and ways of

safeguarding the work areas and workers in the industries and other organizations. I would

like to suggest that the SIWES period be increased to nine months or one year.

2.Universities should ensure that all students on industrial attachment are visited in their

work stations so as to boost students morale and help them increase their commitment

towards the programme. It will also monitor and ensure that students are receiving the right

training.

3.It was observed that each time rain falls; we would not be able to work on site due to

severe weather and construction activities would stand still. I would like to suggest again that

the National University Commission (NUC) should try and arrange the school calendar in

such a way that Engineering/Technology students will be having their own programme in the

dry season so that they will be able to utilize the whole of SIWES period for serious work.


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REFERENCES

Nigeria LNG Limited, NLNG Six Project, 2006, Instruments Installation procedure,

pp 6-11.

Nigeria LNG Limited, NLNG Six Project, 2006, Continuity Testing Procedure, pp 10-

18.

Nigeria LNG Limited, NLNG Six Project, 2006, Punch Listing Procedure, pp 4,5, 13

& 14

Engineering Practice (DEP) Manual (Used by Companies of the Royal Dutch/Shell

Group) on Equipment, Pressure Testing equipment and Systems, pp 5-6.

Design and Engineering Practice Manual (Used by Companies of the Royal

Dutch/Shell Group), General Requirements, pp 60-62.

HRP (Human Resource Services),http://bonny.nlng.com/,23/10/08.

Human Resources Planning, What We Do,http://dev.nlng.com/Default.htm,23/10/08.

Manpower Planning and Resources, MD Organogram,

http://lagos.nlng.com/HR/HRR/organogram.htm,23/10/08.

http://dev.nlng.com/hrp/HRP_2/In-

house/Operations/Materials/general/Operator%20dic.htm,23/10/08.
http://bonny.nlng.com/http://bonny.nlng.com/http://bonny.nlng.com/http://dev.nlng.com/Default.htmhttp://dev.nlng.com/Default.htmhttp://dev.nlng.com/Default.htmhttp://lagos.nlng.com/HR/HRR/organogram.htmhttp://lagos.nlng.com/HR/HRR/organogram.htmhttp://dev.nlng.com/hrp/HRP_2/In-house/Operations/Materials/general/Operator%20dic.htmhttp://dev.nlng.com/hrp/HRP_2/In-house/Operations/Materials/general/Operator%20dic.htmhttp://dev.nlng.com/hrp/HRP_2/In-house/Operations/Materials/general/Operator%20dic.htmhttp://dev.nlng.com/hrp/HRP_2/In-house/Operations/Materials/general/Operator%20dic.htmhttp://dev.nlng.com/hrp/HRP_2/In-house/Operations/Materials/general/Operator%20dic.htmhttp://dev.nlng.com/hrp/HRP_2/In-house/Operations/Materials/general/Operator%20dic.htmhttp://dev.nlng.com/hrp/HRP_2/In-house/Operations/Materials/general/Operator%20dic.htmhttp://lagos.nlng.com/HR/HRR/organogram.htmhttp://dev.nlng.com/Default.htmhttp://bonny.nlng.com/

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