PAKISTAN PETROLUEM LIMITEDINTERNSHIP REPORT

QAZI MUHAMMAD FAISALPAKISTAN AIR FORCE-KARACHI INSTITUTE OF

ECONOMICS AND TECHNOLOG

JANUARY 29, 2016

I WOULD LIKE TO APPRECIATE THE COOPERATIVE ATTITUDE OFALL THOSE PROFESSIONAL

PEOPLEFOR PROVIDING ME

SUCH A GREAT OPPURTUNITY

THANKINGYOU QAZI-MUHAMMAD-FAISAL

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CONTENTS

1.INTRODUCTION

2.QHSE

3.ELECTRICAL POWER GENERATION

4.MAINTAINCE

5.INTRUMENTATION

6.PROCESS

7.BOILER

8.WATER TREATMENT PLANT

9.LABORATORY

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Chapter 1

INTRODUCTION

1.1 PAKISTAN PETROLEUM LIMITED

Sui is situated in Dera Bugti in Balochistan province. In 1949, Government of Pakistan

allowed Burma Oil Company to conduct aerial survey of Sui. The survey was a

successful one. Pakistan Petroleum Company (PPL) came into being on 5th June 1950 and

drilled the first well on 10th October 1951. Since then, 107 wells have been drilled in the

area.

The elliptically shaped Sui field had almost 10 trillion cubic feet recoverable reserves at

the time of discovery. Sui field has contributed almost 30% of the total gas production in

the country since then

1.2 PPL-OPERATED FIELDS:

Pakistan Petroleum Limited operates producing fields in Baluchistan, Sindh and the Punjab:

• Sui Gas Field • Shahdad Gas Field • Kandhkot Gas Field • Gambat South Block • Adhi Field • Adam West Field • Mazarani Gas Field • Adam Field • Chachar Gas Field • Hala Block

1.3 GAS PURIFICATION PLANT

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Natural gas that contains Sulpher bearing compounds Carbon dioxide is called sour or

raw gas. Carbon dioxide reduces the heating value of the gas whereas Sulpher is

corrosive and toxic. Natural gas is thus required to be cleaned from these acid gasses.

Purification plant is installed to remove these gasses from the raw gas and convert it to

sweet gas.

Purification Plant started working in 1955. To further increase the quality of the gas, the

moisture present in it is required to be removed. For this purpose, dehydration units were

installed in 1978.

PPL took over the Purification Plant in July 2002. Before that, it was the property of Sui

Southern Gas Company Limited. PPL is now the sole operator of Sui gas field.

1.4 GAS COMPRESSION PLANT

In 1980s PPL engineer recognized a problematic issue for the pressure of the gas founded

in wells and is decreasing day by day so as to encounter the problem of dropping

pressure.

For this purpose the higher management of PPL decided to establish SUI FIELD GAS

COMPRESSION STATION (SFGCS) for maintaining pressure.

Raw gas is coming from two headers Southern and Northern, and then collected in one

place which is then distributed to Sui main lime stone (SML) & Sui upper limestone

(SUL) units.

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Chapter 2

HEALTH, SAFETY & ENVIRONMENT

2.1 WATER RESERVOIRS

The pumps of the New & Old Hydrant System take water from the Raw Water

Reservoirs. There are 5 raw water tanks installed in the plant with a cumulative capacity

of 1,770,000 gallons.

2.2 FIRE SERVICE STATION

If there is a requirement (i.e. there is a fire in the plant), fire service station is called to

confine the fire. Station is VHF Radio Linked and has a strength of 16 person (4 are head

fire man, 4 are drivers & 8 fire man). They work in 2 shifts and are present round the

clock.

2.2.1 FIRE EXTINGUISHERS

Fire extinguishers are installed at almost all the places of the purification plant. Fire

extinguishers used are of different sizes according to their capacity to hold extinguishing

material, such as 6 Kg, 12 Kg, 30 Kg etc. Different types of fire extinguishers are used

according to the type of fire. Brief description of the fire extinguishers is as follows.

2.2.2 CO2 Fire Extinguisher:

It is used for class B & C type of fire. Main features are

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2.5 to 100 lb of CO2 at 150-200 psia is present

Discharge time is about 18 to 30 seconds

There is no pressure gauge therefore the quantity present in the cylinder cannot be

known. Therefore after use, it is refilled completely

Effective range of 3 to 8 feet

Extinguishing is done by smothering

Effectiveness decrease as temperature of burning material decreases

2.3 PERSONAL PROTECTIVE EQUIPMENT (PPE)

Workers should protect themselves from hazards such as falling objects, harmful

substances, and noise exposures that can cause injury. Workers should use all feasible

engineering and work practice controls to eliminate and reduce hazards. But it is not

possible to eliminate all hazards. Therefore workers should use personal protective

equipment (PPE) where required. Workers should implement a PPE program where they:

Assess the workplace for hazards

Use engineering and work practice controls to eliminate or reduce hazards before

using PPE

Select appropriate PPE to protect employees from hazards that cannot be

eliminated

Inform employees why the PPE is necessary, how and when it must be worn

Train employees how to use and care for their PPE, including how to recognize

deterioration and failure

Require employees to wear selected PPE

PPE includes protective equipment for

Clothing

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Head Protection

Foot Protection

Hand Protection

Eye Protection

Hearing Protection

Respiratory Protection

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Chapter 3

ELECTRICAL POWER GENERATION

3.1 PURIFICATION PLANT

Electrical purification plant is responsible for the maintenance of all the electrical

problems of the purification plant. motors, lighting, Steam Turbine, Gas Turbine and

Diesel Engine driven Generators are installed in the plant for the production of electricity.

These generators are present at four different installations. Description of each generator

is as under:

3.1.2 DIESEL ENGINE DRIVEN GENERATORS

In these generators, diesel engine works as the prime mover. There are five diesel

generators installed in the plant. All of them are standby power sources, used only when

there is a shut down of Turbine driven Generators. Following is the description of each

one.

a. DG 1, 2:

Engine: Cummins

Generator: Siemens

RPM: 1500

Power Factor: 0.8

Generator Output: 240 KW

b. DG 3, 4, 5:

Engine: Cummins

Generator: Leroy Somer

RPM: 1500

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Power Factor: 0.8

Generator Output: 240 KW

There are two tanks of diesel (288 gallons each) to supply fuel to the engine.

3.1.3 TURBINE DRIVEN GENERATORS

There are, four steam and two gas, turbine driven generators installed in the plant. Brief

description of each system is as follows. TG 3, 4, 6, & 7 uses steam turbine as the prime

mover where as TG 1 & 2 uses gas turbine as the prime mover.

3.2 COMPRESSION ELECTRICAL GENERATION

Same as purification plant compression plant as its own power generation plant .there are four turbo generator.

TURBO GENERATOR

Four gas turbine driven generators G-501A/B/C and D are installed to meet the electrical load requirement of SFGCS. Normally three generators are running and one is standby or under maintenance.

Capacity = 4x 4010 KVA4x 3.2 MW

Voltage and frequency 6.6 KV, 50 HZ

Which are synchronized with other and form a main power bus and thus further distributed by number’s sub-station

TRANSFORMER Now this main line is connected to a step up transformer 1100 voltsto transmit the power where ever required

Power generation in compression plant is separately engaged by 4 gas turbine.

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Power is generated at 3 phase 6600 Volts, 50Hz, and distributed to step down transformer through HT circuit breakers. The distribution transformer step down 6.6KV into 3-phase 400Vots, neutral solidly ground. The transformer secondary supply is connected to motor control center MCC panels through LT, air circuit breaker (ACB). Mostly power is consumed at 3- phase 400Volts 50 Hz supply. One emergency generator is installed for emergency power supply.

SUB-STATION 01

Transformer T-7 and T-8 are connected to plant services board MCC panels

SUB-STATION 02

Transformer T-9 and T-10 are connected to MCC panels of C101A and C101-B in following distribution order.

SUB STATION 03

Transformer T-1 and T-2 is connected to MCC panels of C101-C and C101-D in following distribution order.

SUB STATION 04

Transformer T-3 and T-4 is connected to MCC panel of C101-C and C-101-

D in distribution patteren.

SUB-STATION 05

Transformer T-5 and T-6 is connected to to MCC panel of C101-E and C-101-

F in distribution patteren.

SUB-STATION 06

Transformer T-11 is connected MCC panel of C-101-G in distribution panel.

SUL MOTOR COMPRESSOR VFD AND MCC PANEL

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SUB-STATION NO.7 (C201A) Converter Transformer T-12 is connected to VFD and Auxiliary transformer T-12A is connected to MCC panels of C201-A. Provision to feed MCC panel of sub-station No.7 from Substation No.8 or vice versa is also incorporated.

SUL MOTOR COMPRESSOR VFD AND MCC PANEL

SUB-STATION NO.8 (C201B )

Converter Transformer T-13 is connected to VFD panel and Auxiliary transformer T-13A is connected to MCC panels of C201-B. Provision to feed MCC panel of sub-station No.8 from Substation No.7 and Substation No. 9 or vice versa is also incorporated

SUL MOTOR COMPRESSOR VFD AND MCC PANEL

SUB-STATION NO.9 (C201C)

Converter Transformer T-14 is connected to VFD panel and Auxiliary transformer T-13A is connected to MCC panel of C201-C.

VFD SYSTEM

Converter Transformer Capacity 3010 MVA, Primary 6.6KVSecondary Delta /Delta/star 2x1175Tertiary winding: 900V

6- Phase bridge rectifier (Thyristers). Rectify 2 X 1175 VAC, 50Hz AC supply into DC supply.

DC link reactor to smooth DC voltage.Diverter

A capacitor and inductor circuit, activated during startup of motor when low frequency, low RPM.

Inverter bridge panel Thyrister Bridge for inverting DC supply into AC supply

Motor output panel . Connected to main motor via motor capacitors and inductor circuit.

Digital Frequency Module DFC module.

DFC module performs following tasks.

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Total control and monitoring of VFD system. Generate and control the firing pulses of thyristers of bridge rectifier, inverter, diverter. Control of Startup and shut down.Initiate Protection alarm and trip signals. Communicate unit control panel in control room. Inter face with programmable logic control (PLC) of chilled water and air-conditioning system of the VFD.

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Chapter 4

MAINTENANCE

Maintenance department is responsible for the maintenance of machines and equipment

installed in the plant for the purpose extracting H2O, H2S and CO2 from the raw gas.

There are hundreds of different types of equipment present in the plant for this purpose.

There are boilers for steam generation, generators for power generation, water treatment

plant for producing de-mineralized water, and many other equipment.

4.1 OVERHAUL DEPARTMENT

As the name suggests, this department deals with the maintenance of stationary (non-

rotating) parts/machines. These include heat exchangers, pressure vessels (scrubber,

surge tank, cooler), cooling towers, boilers, pipelines, valves etc.

Heat Exchangers: There are two types of heat exchangers, Shell & Tube Type and Plate

Type, used in the plant. Maintenance of heat exchangers include cleaning of dust and

scales from tubes. If any tube is found to be leaking, it is plugged (closed). By these the

efficiency of the heat exchanger increases as the rate of heat exchange increases.

Vessels: There are many vessels installed in the plant for various operations. These

include Inlet Scrubber, MEA Contactor, MEA Scrubber, Glycol Contactor, Glycol

Scrubber, Condensers etc. These vessels are overhauled from time to time on a set

schedule or if there is any discrepancy noticed in there operation.

Valves: All the valves come under the responsibility of Overhaul Department. Valves

usually leaks after a period of time. If possible, the leakages are stopped, otherwise the

valves are changed. Leakages problems are addressed using gland packing.

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Pipes: Repair of leakages in pipes, repair of insulation, and removal of redundant

elements of pipes is also performed by overhaul department.

4.2 ROTARY DEPARTMENT

This department is responsible for the maintenance of the equipments having rotating

parts in them. Steam run turbines are used in the plant for various purposes like in,

generators, compressors, pumps etc. A brief description of each is as follows

Turbine: Turbine is used in the plant for the purpose of giving drive to compressors,

pumps, fans and generators. Most of the turbines are velocity compounded, two row

impulse type. Almost all the turbines at purification plant are steam driven. Maintenance

department is responsible to look after the leakages, functional problems of the turbine.

Compressor: Compressors are installed in the plant to compress air (for the use of

instruments). These are reciprocating compressors using steam turbine or electric motor

as the driver.

Pumps: Pumps are used to increase the pressure of a fluid. If a pump is not working, it is

unassembled and the faulty part is replaced. Help from plant workshop is also taken if

any repair work is required.

a. Centrifugal Pump: Centrifugal pumps are used to pump MEA. Seven stage

centrifugal pump is used to pump MEA into the MEA contactor. There are 22

MEA pumps installed in 8 banks giving output to a common header. Feed

water pump for boilers is also multistage centrifugal pump. Single stage

centrifugal pumps are used for reflux condenser, bearing cooling, water

circulation, brine solution pump, raw water transfer pump, soft water transfer

pump etc.

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b. Reciprocating Pump: Reciprocating pumps are used for pumping Glycol in

the Glycol contactor, and demin water injection in MEA contactor.

Cooling Fans: Cooling fans are used in cooling towers. As it is a rotary machine, it

comes under maintenance department. Cooling towers of TG6 and TG7 also has electric

motor driven fans. Lubricating oil is changed regularly so that the fan operates

efficiently.

4.3 MAINTENANCE ROUTINE

4.3.1 SHUTDOWN MAINTENANCE

If during operation, any equipment is not working properly then it is taken for shutdown

maintenance. It is of most importance as it can cause stoppage in process.

4.3.2 PREVENTIVE MAINTENANCE

Preventive maintenance is done to protect the equipment from breakdown and keep the

equipment working efficiently. This includes oil change, cleaning, etc. During preventive

maintenance, standby equipments are used so that there is no effect on the process.

Preventive maintenance is done according to a schedule made on the basis of availability

of workers.

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Chapter 5

INSTRUMENTATION

Instruments are installed on the equipment to monitor their performance parameter so that

the process can be kept within the optimum performance zone. Instrument Department is

responsible for the installation and maintenance of these instruments. Instruments are

either pneumatic or electric. The signals from the instruments are transmitted to control

rooms were the outputs are monitored round the clock.

5.1 PROCESS PARAMETERS

Four parameters are most important in any process industry. These are

5.1.1 PRESSUREThe pressure of the fluid flowing through the pipes is measured. Bourdon Tube is used to

measure pressure. Pressure control valves are used to keep the pressure within the set

region.

5.1.2 TEMPERATURETemperature is measured using thermocouple. Temperature instruments are installed at

inlet/outlet of heat exchangers, vessels, coolers, etc.

5.1.3 FLOWFlow meters are used to find the flow of a fluid through a vessel, pipe. Differential of

pressure is measured to evaluate the flow rate through a pipe.

5.1.4 LEVELLevel of the liquid in a vessel is monitored using Reflex Gauge

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Chapter 6

PROCESSThe main purpose of the Gas Purification Plant, as the name suggest, is to purify the

Natural Gas extracted from Sui. The extracted Natural Gas contains impurities which

reduces its heating value. For the gas to be used as a source of energy, it is required to be

cleaned from these impurities. The main impurities present in Gas are Hydrogen Sulphide

(H2S) and Carbon dioxide (CO2) and Water (H2O). The Process Department of the Gas

Purification Plant is responsible for carrying out the purification process of the gas.

6.1 GAS PURIFICATION PROCESS

Purification mainly consists of two processes, Sweetening Process and Dehydration

Process. A brief description of these is as under.

6.2 SWEETENING PROCESS

This is likewise called Gribotol Process and is completed to evacuate corrosive gasses (H2S and CO2) from the crude gas. Crude gas contains roughly 95 grains for each million standard cubic feet (MMSCF) of Hydrogen Sulfide and 7% by volume Carbon dioxide.

The synthetic utilized as a part of this procedure is Mono Ethanol Amine (MEA). MEA ingests corrosive gas when it interacts with the crude gas in the MEA contactor. MEA is then reactivated so it can be utilized once more. After this procedure, the sweet gas contains girl then 0.25 grains for each MMSCF of Hydrogen Sulfide and 0.25% by volume of Carbon dioxide.

6.2.1 MEA FLOW

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The flow of MEA through different vessels is as follows

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MEA Contactor

Flash Tank

Lean/Rich Heat Exchanger

MEA Reactivator

Re-boilers

Reflux Accumulator

Reflux Condenser

Re-claimer

Primary Cooler

Secondary Cooler

L/R Heat Exchanger

Surge Tank

MEA Contactor

MEA Scrubber

6.3 DEHYDRATION PROCESS

Sweet gas coming from the banks is cleaned from acid gasses but contains large

percentage of water in it. To further improve the quality of the gas, water contents need to

be removed. For this purpose, dehydration units are installed in the plant. The chemical

used for dehydration is Tetra Ethylene Glycol (TEG). In the Glycol Contactor, TEG

absorbs water contents from sweet gas. The dehydrated gas contains approximately 7 lbs

per MMSCF.

6.3.1 TEG FLOW

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Glycol Contactor

Glycol Flash Tank

Glycol Filters

Glycol Scrubber

Re-concentrator Column

Glycol SurgeTank

Glycol Contactor

GlycolRe-concentrator

Glycol/Glycol Heat Exchanger

Glycol Cooler

Sweetening

6.4 GAS FLOW

6.5 PROCESS CONTROL ROOM

Process Control Rooms are established to monitor the purification process. Pressure,

temperature, flow and level control instruments are installed in sweetening banks and

dehydration units. Output of these instruments can be monitored and controlled from the

control room. There are two control rooms:

Old Process Control Room

New Process Control Room

6.6 OPERATION IN COMPRESSION PLANT

SML

SUL

HRL

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Inlet Scrubber

Sales Gas Header

Raw Gas Header

MEA Scrubber

Sweet Gas Header

Inlet Scrubber MEA Contactor

Glycol ContactorGlycol Scrubber

From SML

FROM SUL

OPERATION: For timely procurement of essential spares and capital equipment, maintenance and

third-party inspection, CD also maintains close liaison with equipment manufacturers and

relevant departments at PPL.

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SML Northern & Southern Header

Compression Plant which is used as a

fuel

DHP SNGPL

Slug Catcher & Scrubbers

SUL

Scrubbers Knockout Drum

Low Pressure Compressor

Cooler Knockout Drum

High Pressure

Slug Catchers Northern & Southern Header

Knockout Drum

Purification Plant

Discharge Header

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Chapter 7

BOILER

Being a cheap source of energy, steam is used in most of the process industries. In Gas

Purification Plant, most of the equipment is steam driven. Steam turbines are used as

prime mover in pumps, compressors, fans, generators, etc. Dry steam is used which is at

high pressure (400 psia) and is superheated (508◦ F).

7.1 MAJOR PARTS OF A BOILER

A boiler has following major parts.

Drums: There are two drums in boiler. One is at the bottom and is filled with water all

the time. It is also called mud drum. The second drum is at the top side is filled with

water and steam.

Furnace: Two burners are present in each furnace. Furnace is also equipped with flame

detectors, which trips the gas line and the boiler if it senses no flame. Gas is used as the

fuel in the furnace. Air is forced in with the help of inlet blowers. An air fuel ratio of 1/10

is maintained. The furnace has a flat tile covered floor.

Superheater: Wet steam from the upper drum of the boiler enters the superheater

chamber. Here it is converted to Dry Steam with a temperature of 508◦ F.

Economizer: The flue gasses leaving the furnace passes through exhaust chamber. Here

heat it exchanges heat with the incoming feed water, and thus heating it up. This way the

efficiency of the boiler increases.

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Water Tubes: The upper drum and the lower drum are connected with each other by

water tubes. These tubes are filled with water. There are two types of tubes, Down-comer

Tubes and Generation Tubes. Burner’s flame heat up the water in generation tubes

causing the water to move up. Hot water moves to the upper drum, and the relatively

cooler water comes down through down-comer tubes.

7.2 BOILER CONTROL ROOM

There are two control rooms to monitor the operation of boilers.

- New Boiler Control Room: For boiler 14 & 15

- Old Boiler Control Room: For Boiler 1 to 3 & 5 to 13

Important parameters like, gas flow rate, air flow rate, steam production rate,

temperatures, pressures can be monitored and controlled from the control room.

7.3 WATER STORAGE TANKS

Feed water tanks are used to store the water coming back in the form of condensate from Process and Utility areas. Demin Water Tanks are used to store de-mineralized water coming from Water Treatment Plant.

7.4 FLOW OF FEED WATER/STEAM

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BoilerCondenser

Condenser

Feed Water Tank

Process Area (50 psia)

Utility Area (27 psia)

Surge Tank De-aerator

Chapter 8

WATER TREATMENT PLANT

Although most of the water required for producing steam comes from the returning

condensate, the shortages of de-mineralized water due to leakages and evaporation needs

to be fulfilled. Moreover, the water required for the cooling tower goes through an open

circuit and additional soft water is required to be feed.

8.1 DEMIN WATER TREATMENT PLANT

Minerals present in the raw water causes scaling and corrosion in the tubes of boilers. So

the water is needed to be de-mineralized. De-mineralized water is also used in MEA

contactor to catch the evaporating amines and thus reduce MEA loses.

Degasifier: Air is blown through the water to remove dissolved Oxygen (O2) and Carbon

dioxide (CO2) from it.

Anion Exchanger: Anions are removed from the system through anion exchanger.

Anion resin is present in the exchanger to catch the anions present in the water.

Mix Bed: Mix bed is also used to remove cations and anions from the water. It is used

when we want to get better quality water with PH closer to 7.

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HCl Dosing Tank: These are used to store HCl. HCl is used to regenerate the cation

exchanger.

Chapter 9

LABORATORY

Laboratory is responsible for the testing of impurities present in different fluids which are

part of the purification process. These include Mono Ethanol Amine (MEA), Tetra

Ethylene Glycol (TEG), Water and Natural Gas. A brief introduction about each fluid and

the tests performed on them is as under.

9.1 WATER

Water is used for drinking, cooling, producing steams, cleaning etc. water being a good

solvent absorbs many impurities that comes its way. Raw water is used for drinking

purposes, De-mineralized water is used in boilers to produce steam (as it does not contain

Silica which causes scaling and corrosion), and soft water is used in cooling towers.

Different tests are performed on each type of water to check the quality. A brief

description of each test is as follows.

a. Hardness: The total hardness present in water is a sum of hardness due to

Calcium and Magnesium. 50 ml water and hardness tester buffer solution is

titrated with Ethyl Diamine Tetra Acetic Acid (EDTA). This gives the total

hardness of the water.

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b. Chloride: 50 ml water, Phenolphthalein indicator and 2 drops of Potassium

Chromate solution is titrated with Silver Nitrate to find the Chloride’s PPM (parts

per million) present in water.

c. Alkalinity: 50 ml water, Methyl Orange indicator and 2 drops of Potassium

Chromate solution is titrated with Nitric Acid to find the Alkalinity in PPMs

(parts per million)

d. Conductivity: Conductivity is checked using conductivity meter. The water

sample is taken in a beaker. Tip of the probe of conductivity meter is dipped in

the sample and the meter shows the result.

e. Silica: Silica presence is measured using Spectrophotometer. The procedure is

that 10 ml sample is taken in two bottles. 14 drops of ‘Molybdate 3 Reagent’ are

added. 4 minutes interval is given before adding ‘Citric Acid’ powder in the

sample. After 1 minute, ‘Amino Acid’ powder is added in first bottles. After one

minute interval, the outer surface of the bottles is cleaned. The second bottle is

used as reference (zero) and the Silica contents are measure from the first bottle.

f. PH: PH is measured using PH meter. The tip of the probe is dipped in the sample

water. The meter reading stabilizes after a few seconds to give the PH value.

g. Ferrous: 1 ampoule Ferrozine is added in 25 ml sample of water. After waiting

for 5 minutes, the PPM of Ferrous is checked using Spectrophotometer.

9.2 MEA

MEA is used in sweetening process to absorb H2S and CO2 from raw gas. Lean MEA

comes in contact with raw gas and absorbs these acid gasses. MEA is now said to be rich.

The quality of MEA is important as it is a very important parameter deciding the quality

of sales gas. Following tests are performed on MEA.

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a. Concentration: Concentration is measured using titration method. Concentration

is found only of Lean MEA.

b. H2S: H2S is measured in Lean and Rich MEA.

c. Suspending Particles: Suspending particles are measured using

spectrophotometer.

9.3 TEGTEG is used in dehydration process to absorb water contents from the gas coming from

banks. Following tests are performed to check the quality of TEG

a. Concentration: Concentration is measured using titration method.

b. Viscosity: Viscosity is measured using viscometer

c. Density

d. Specific gravity

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