internship report of Kepco

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Abstract

Samman sammi03475070922

The report is about my internship tenure which made me learn the basics of a combined cycle power

plant. There are ten Gas turbines and 10 HRSGs and 5 steam turbines (one steam turbine with every two

gas turbines) thus successfully following energy economy policy. The auxiliary systems with the main

units are extremely efficient at KAPCO.A very passionate management / a highly skilled and disciplined

man power and most importantly their mutual coordination makes KAPCO known all

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Acknowledgement

Thanks to Almighty ALLAH WHO gave me the strength and will to go out in search of knowledge and

WHO is always our greatest well wisher.

I would thank Engr. Mahmood Rahim & Engr. Arif Mahmood who has assisted me throughout my

internship tenure. Besides his engineering skills and knowledge they are thoroughly a well disciplined

personality. I would always remember their ditch efforts to make me and my fellows entangled in

discussions that ultimately proved to be very fruitful .It was a real feast being with him.

I am very obliged to all the personalities who were always there whenever I asked for help. It was really

a very good experience to be at KAPCO.

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KAPCO: AN INTRODUCTION Machining: An Introduction

Power Plant Technology


TABLE OF CONTENTS

COMBINED CYCLE POWER PLANT

Introduction

Functional Description

GAS TURBINE & ITS WORKING PRINCIPLE

Main components of gas turbine Working

Principle (BRAYTON CYCLE)

TURBINE WASHING

General Description

Pre washing

Washing

STEAM TURBINE AND ITS WORKING PRINCIPLE

FUELING OF THE PLANT

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Main Components of a Steam Turbine cycle

LUBRICATION SYSTEM

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A Leading Power Generation Company


KAPCO: AN INTRODUCTION

Kot Addu Power Company Limited (KAPCO)

On June 27, 1996, following international competitive bidding by

the Privatization Commission Government of Pakistan (the

"Privatization Commission"), the management of KAPCO was

transferred to National Power (now International Power) of the

United Kingdom, which acting through its subsidiary National

Power (Kot Addu) Limited ("NPKAL"), bought shares

representing a 26% stake in KAPCO. Later, NPKAL bought a

further 10% shareholding in KAPCO increasing its total

shareholding to 36%.

Kot Addu Power Plant (the "Power Plant") was built by the Pakistan Water and Power Development

Authority ("WAPDA") in five phases between 1985 and 1996 at its present location in Kot Addu, District

Muzaffargarh, Punjab. In April 1996, Kot Addu Power Company Limited ("KAPCO") was incorporated as

a public limited company under the Companies Ordinance, 1984 with the objective of acquiring the

Power Plant from WAPDA. The principal activities of KAPCO include the ownership, operation and

maintenance of the Power Plant.

Shareholding Structure:

Following the successful completion of the Offer for Sale by the Privatization Commission (on behalf of

WAPDA) in February 2005, 18% of KAPCO's shareholding is now held by the General Public. On April

18, 2005 KAPCO was formally listed on all three Stock Exchanges of Pakistan.

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Location

The Power Plant is situated in District Muzaffargarh, Punjab, 90 K.M. north west of Multan on the left bank of the River Indus at a distance of 16 K.M. from Taunsa Barrage. The area is surrounded by agricultural land on the north and west side of Kot Addu.


POWER PLANT TECHNOLOGY

Kot Addu Power Company Limited ("KAPCO") was incorporated in 1996 with the purpose to contribute economical power to the national grid. KAPCO has shown exceptional results in the area of plant maintenance, availability, quality standards and financial performance. In April 2005 KAPCO was formally listed on all the three Stock Exchanges of Pakistan. KAPCO is committed to contributing to Pakistan's economy by powering the lives of its people by continuously improving its performance through efficient systems, capable workforce and good governance.

The Power Plant is a multi-fuel gas-turbine power plant with the capability of using 3 different

fuels to generate electricity, namely: Natural Gas, Low Sulphur Furnace Oil and High Speed Diesel to

generate electricity. The Power Plant is also the only major plant in Pakistan with the ability to self start

in case of a country wide blackout.

KAPCO is Pakistan's largest Independent Power Producer (IPP) with a name plate capacity of 1600

MW. The Power Plant comprises of 10 multi fuel fired gas turbines and 5 steam turbines installed in 5

phases between 1985 and 1996. These turbines are divided into 3 energy Blocks with each Block

having a combination of gas and steam turbines. The Power Plant's combined cycle technology enables

KAPCO to use the waste heat from the gas turbine exhaust to produce steam in the Heat Recovery

Steam Generator, which in turn is used to run the steam turbines thereby resulting in fuel cost efficiency

and minimum wastage.

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PLANT GENERAL CHARACTERISTICS

Block-1

GT 1,2 and ST 9,10

Manufacturer Siemens GermanyCapacity of Gas turbine 2*97MW = 194 MWCapacity of Steam turbine 100 MW with 2 HRSG’s


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In a combined cycle power plant (CCPP), or combined cycle gas turbine (CCGT) plant, a gas turbine generator generates electricity and the waste heat is used to

make steam to generate additional electricity via a steam turbine; this last step enhances the efficiency of electricity generation. In a thermal power plant, high-temperature heat as input to the power plant, usually from burning of fuel, is converted to electricity as one of the outputs and low-temperature heat as another output. As a rule, in order to achieve high efficiency, the temperature difference between the input and


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10

5

1600MW

1541MW

1345MW

1360MW

6 x 132 KV

6 x 220 KV

35,667MWh

GAS TURBINES

HRSGs

STEAM TURBINES INSTALLED

CAPACITY MAX. LOAD

GENERATION

LOAD ACC TO IDC TEST (1996) LOAD

ACC TO ADC TEST (2004) NUMBER OF

FEEDERS

MAX GENERATION IN ONE DAY

Combined cycle Power Plant

INTRODUCTION:

A combined cycle is characteristic of a power producing engine or plant that employs more than one thermodynamic cycle. Heat engines are only able to use a portion of the energy their fuel generates (usually less than 50%). The remaining heat (e.g. hot exhaust fumes) from combustion is generally wasted. Combining two or more "cycles"

BRYTON CYCLE

RANKINE CYCLE

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output heat levels should be as high as possible. This is achieved by combining the Rankine (steam) and Brayton

Working principle of a combined cycle power plant


An open circuit gas turbine cycle has a compressor, a combustor and a turbine. In this type of cycle, the input temperature to the turbine (the firing temperature), is relatively high (900 to 1,400 0c). The output temperature of the flue gas is also high (450 to 650 0c). This is therefore high enough to provide heat for a second cycle which uses steam as the working fluid; (a Rankine cycle).

In a combined cycle power plant, the heat of the gas turbine's exhaust is used to generate steam by passing it through a heat recovery steam generator (HR5G) with a live steam temperature between 420 and 580 0c. The condenser of the Rankine cycle is usually cooled by water from a lake, river, sea or cooling towers. This temperature can be as low as 15 °C.

Combined cycle plants are usually powered by natural gas, although fuel oil, synthesis gas, Furnace Oil, High speed Diesel or other fuels can be used. The supplementary fuel may be natural gas, fuel oil,

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COMBINE CYCLE GAS TURBINEGAS TURBINE

A gas turbine, also called a

combustion turbine, is a rotary engine that extracts energy


In a thermal power station water is the working medium. High pressure steam requires strong, bulky components. High temperatures require expensive alloys made from nickel or cobalt,rather than inexpensive steel. These alloys limit practical steam temperatures to 655 O( while the lower temperature of a steam plant is fixed by the boiling point of water. With these limits, a steam plant has a fixed upper efficiency of 35 to 42%.

DIFFERENCE BETWEEN OPEN AND COMBINED CYCLE:

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from a flow of combustion gas. It has an upstream compressor coupled to a downstream turbine, and a combustion chamber in-between. (Gas turbine may also refer to just the turbine element.)

Energy is added to the gas stream in the combustor, where air is mixed with fuel and ignited. Combustion increases the temperature, velocity and volume of the gas flow. This is directed through a nozzle over the turbine blades spinning the turbine and powering the compressor.

Energy is extracted in the form of shaft power compressed air and thrust in any combinationand used to power generators.


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MAIN COMPONENTS OF A GAS TURBINE

Intake Air Filters

These provide clean, filtered and dust free air to the compressor inlet.

Compressor

Air is drawn in and compressed when passing through rows of rotating blades and stationary vanes. There are total 16 stages in compressor. At the end of the compressor, before reaching the combustion chamber, the air is compressed to about 10 bar and has been heated to about 310°C by compression.

Combustor / Combustion Chamber

The combustor or combustion chamber is the heart of the engine; here the combustible mixture of compressed air and fuel is burnt. The hot gas output temperature becomes 10000C to 1300°C; its volume becomes more than doubled by the temperature rise where as pressure remains constant.

Compressed air having about 10 bars pressure and 350°C temperature. The pressurized air that delivered by the compressor flows around the hot gas path and outer casing paths. Cooled air, which came from compressor, cooled down the inner casing of combustion chamber. Compressed air serves as a heat exchanger of the combustion chamber.

Both combustion chambers have eight separate burners. These burners may equip gaseous, liquid or dual fuel operation. The oil burners designed on reverse flow principle without any moving parts. High temperature combustion is provided with refractory linings on its upper portion. These combustion chambers are very easy to assemble and disassemble, so they are easy for inspection and they have good accessibility for all components. In case of gas ,it has two modes of combustion.

• DIFFUSION MODE in which burner has a long flame burning.• PREMIX MODE in which burner has a cattle shape flame burning.


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Turbine

The turbine section converts the thermal and kinetic energy of the combustion gases into rotational mechanical energy. Gas turbines like steam turbines have three or four stages of rotating and stationary blades. However; because gas turbines work with lower initial inlet pressures, they have fewer stages and less change in blade height from inlet to exhaust. Turbines normally consist of combination of impulse and reaction types. The gas turbine also differs from the steam turbine in;

• the type of blading material used• the lower ratio of blade length to wheel diameter• less number of turbine stages

Flue gases flow to the turbine with a very high velocity v of about 80 mjs (288 km/hr). It means it has high kinetic energy. The kinetic energy of flue gases is converted to mechanical energy when flue gas is expanded in the stages of turbine transferring its energy to the turbine rotor.The volume of flue gases is increased by expansion and thus temperature is decreased and at the exhaust it is about 500C

The turbine parts which are mechanically stressed are at the same time subject to very high temperature, so that these parts are designed with special material and cooling paths are provided for cooling air to flow.

Exhaust diffuserIt diverts the de-energized (but still hot) flue gases into the ambience to complete the cycle. It is

fitted with filter and silencer.

Bearings:Bearing are used to lift the shaft, to make the vibration of rotor as small as possible and to make

the friction during the movement of the shaft. As shaft is connected with bearing, this shaft is lifted by oil flowing in the bearing. The main purpose of using oil in these bearings is cooling of bearings which are heated because of running of the shaft. Friction is also reduced when we use oil in the bearing.


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TURBINE WASHING

Why is it necessary?

After every 250 hours, when the GAS turbine is being operated at Low Sulphur Furnace Oil (LSFO) it is recommended to carry out water wash of turbine blades.Actually there accumulates sulphur on blades surfaces which is present in the furnace oil.This accumulation of sulphur on blades surface causes a decrease in their efficiency.Therefore it is required to carry out washing after every 250 hours when machine being operated at LSFO.

PRE-Washing Procedure:

While the turbine is in full operation the temperature of the burning gases inside turbine is about 1100 to 1150 C and cooling of the turbine blades is always required to have a proper function and for the safety of blades. To keep them cool blowers are available and a discharge line is also taken out from compressor to the rotor for the cooling purpose.

The wheel space temperature is the temperature of Blades space of rotor and stator blades.Its about 380 C to 480 C.

• Before washing turbine unit is shutdown and transferred to turning gear motor.• The speed of Turning Gear Motor is 110 rpm.• The spead of the rotating rotor gradually slows down from 2900 /3000 rpm and when it reaches

110 rpm its automatically transferred on Turning Gear Motor.• After 6 to 7 hours the wheel space temperature reaches 150 C.• This time limit is usually for summers and for winters this time is comparatively less.

WASHING:

• Then Turbine is given Crank start at crank speed of 475 rpm with the help of starting motor.• Then Washing Pump is started simultaneously.• Hot water at a temperature of 80c is used to wash turbine blades

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1. WASHING IS CARRIED OUT FOR 25 minutes.2. The Turbine rotor is brought at zero rpm after 25 min washing.3. During this time the temperature of wheel space is about 80 C. At this temperature Thermal stresses

are avoided and sagging is thus avoided.4. Then 40 min are given without any operation while rotor remains at zero rpm.5. Then after 40 mins turbine is given crank speed with the help of starting motor and washing is again

carried out for 25 mins.6. From now onwards machines are started normally.7. The whole Turbine washing is to be taken out within 12 hours and machine must be made available

within this time.


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STEAM TURBINE


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GENERAL DESCRIPTION:

A Steam turbine is a turbine that works with the help of superheated steam that has no moisture. We need moisture free steam because of certain reasons. For example the moisture may cause rust and the surface of blades corrodes. The blades of a turbine are very expensive and there replacement causes wastage of huge sum of money and time which increase cost of energy production and this renders a huge loss to the company.

A combined cycle employs gas and steam turbines. Its called a combined cycle because the exhaust gases obtained by utilizing gas in the gas turbine after its combustion in the combustion chamber. The temperature of these hot exhaust gases is very high ranging from about 480 to 510 C. Instead of wasting such a huge amount of energy into the atmosphere this energy of exhaust gases are used in steam turbine to produce superheated steam to run a steam turbine.

At KAPCO a steam turbine is installed with every two gas turbines. The exhaust gases of each gas turbine are utilized in HEAT RECOVERY STEAM GENERATOR (HRSG) which is a non-conventional boiler. A complete description of HRSG is discussed later.

Two HRSG boilers produce superheated steam that runs a steam turbine. The efficiency of combined cycle is higher than a closed cycle. Its about 35 % to 40 %.whereas the efficiency of a gas turbine is 25 % to 30 %.Although the efficiencies may vary depending upon the designs of particular gas turbines and steam Turbines. Here these Efficiencies are for SIEMENS gas turbine and steam turbine. SIEMENS is Turbine manufacturer based in germany.When a single Gas Turbine is functioning then only one HRSG system works for that gas turbine and therefore load of steam turbine is halved.

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SCHEMATIC DIAGRAM OF STEAM TURBINE


Main components of a steam Turbine are discussed as below:

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Main Components of a Steam Turbine cycle:

• Boiler(HRSG)• Turbine

• Condenser

• PumpNow they are discussed in detail separately along with their auxiliaries and other components:

1. BOILER (HRSG):

The exhaust gases of a gas turbine are at a high temperature and such hot gases are utilized in Heat Recovery Steam Generator (HRSG) . The efficiency of HRSG is relatively higher than conventional boilers i.e. 40% to 45 % whereas the efficiency of conventional boilers is about 35 0/0 and that of Burners Boiler is 32% to 40 %.

The HRSG has the capacity of about 200 tons of steam production in it. There are different stages of a HRSG.There are generally four stages:

1.LP Evaporator2.HP Economizer3.HP Evaporator4.Superheater

1- LP Evaparator:

The LP Evaporator is basically a Heat Exchanger ( parallel flow ) consisting of a bundle of tubes confined in a large shell or cylinder.

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The hot water coming from hot well passes through these tubes.The hot water at a temperature of about 125 C to 130 C from feed water tank at low pressure than atmospheric pressure flow through these tubes.The water flows trough these tubes with the help of Low Pressure Pumps at Feed Water Pumps Building where these pumps pick hot water from feed water tank and make it flow through LP Evaporator tubes by first bringing it in LP DRUM that is connected with LP Evaparator.LP Drum maintains low pressure saturated steam in it ..The LP Evaporator is the top most stage a of vertically designed HRSG.The exhaust gases of a gas turbine reach LP Evaporator at the last when the temperature of these gases has been utilized in first three stages. The temperature of these gases at this stage is about 180 C.When these gases passes across the water containing tubes it goes through a phase change where water is converted into steam with a little increase in temperature. The Latent heat is added in water due to which it is converted in steam by maintaining its temperature.About 1/5th volume of water in LP Drum is converted into saturated steam and rest of the water keep flowing in cycle through tubes or LP Evaporator until it is also converted into saturated steam.The level of LP Drum is maintained at certain level which is controlled through automatic level detectors. These send electrical signals to Central Control Room where the readings are viewed on computer screen.Now the low pressure saturated steam produced in LP Evaporator going through LP Drum that is used for the purpose of Dearation in DEARATOR.

DEARATOR & its Function:

DEARATOR is drum mounted just below Feed Water tank (As shown in the fig). The purpose of Dearator is to de-air the hot water at a temperature of 125 C to 139 C coming from the HotWel1. A Dearator has two inlets. One form hot well and the other from LP Drum.The hot water coming from the Hot Well is showeed in the dearator and low pressure saturated steam is blown through this showered water. As air becomes lighter by heating therefore by mixing steam with this showered water the temperature of air available in hot water increases and it rises and finally it is drained out from Dearator top. The hot water collected at the bottom of Dearator drum is air-free and is then used convert into steam in HRSG.

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2- HP ECONOMIZER:

High Pressure (HP) Economizer is also a heat exchanger (counter flow) consisting of a bundle of tubes. High Pressure Feed water Pumps placed in the Feed Water Pumps Building take water from Feed Water Tank placed below Dearator and make it flow through HP Economizer. High pressure is developed with the help of High Pressure Feed Pumps. Here at steam turbines 11 & 12 impeller type Centrifugal pumps are being used for this purpose(Pump has been viewed in detail). High pressure is developed so that maximum heat can be absorbed in the economizer by water at higher pressure (The boiling point of a liquid increase with an increase in pressure).The flue gases exchange heat to hot water in the tubes of HP Economizer and raise its temperature to about 140 CAt this heat exchanger there is a sensible heat addition where there is an increase in temperature of water in the tubes instead of phase change (steam). This high temperature water flows down to HP Drum.

3- HP EVAPORATOR:High Pressure Evaporator is also another heat exchanger (Parallel Flow) consisting of a bundle of tubes through which hot water coming from second stage of the HRSG flows at high pressure.As discussed before that water comes in HP Drum from Economizer. Then this high temperature water from HP Drum is taken from suction pump and made flown through HP Evaporator where there is Latent Heat Addition into the water.The water is converted into high pressure saturated steam. This steam then goes again in HP Drum where it maintains high pressure in which high pressure steam is present over a certain level of water. This HP steam whose temperature is about 270 C flows through the last stage of HRSG called superheater whereas water that has not been converted into steam in the HP Evaporator is brought again into HP Drum by Reciprocating Pump.

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4- SUPERHEATER:

Superheater is another type of heat exchanger (counter flow) consisting of a bundle of thin walled tubes for the maximum rate of heat exchange. This part of the HRSG is located directly in front of the exhaust section where flue gases at a temperature ranging from 480 C to 500 C are coming out. Superheater utilizes the maximum temperature of hot flue gases and there is a sensible heat addition in the saturated steam coming from HP Drum; thus increasing temperature of steam in the tubes and making saturated steam superheated and moisture free. The temperature of this superheated steam is about 480 C to 500 C. This superheated steam at pressure of about 35 Bars then runs the steam turbine

CONDENSER:

GENERAL ARRANGEMENT:

The Condenser consists of a hotwell and a shell of rectangular shape, on which is placed a pyramidal neck which is connected to the turbine exhaust hood by means of the expansion joint and the rectangular neck.The condenser is placed directly on concrete foundations with no flexible suspensions ( or springs) or counter reaction devices.Connection between the condenser hotwell and the condensate extraction pumps is provided by means of pipings. Each of the four tube bundles is fed through an inlet and outlet waterbox which is bolted together to the tube sheet. The water boxes are specially designed to uniformly distribute the cooling water flow in all tubes. The four tube Bundles are identical.

The following main circuits are placed in the condenser shell :Drain issuing from the flash tankAir and Non-condensable gases extraction device.Make-up water.

Main Components/Parts:• Water Boxes• Bundles• Tube Bundles• Air coolers• Tube sheets• Exhaust Neck• Lower Exhaust Neck

• Upper exhaust neck

• Stainless steel expansion joint installation• Supports and Anchoring.

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FUELING OF PLANT

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Since the plants at kapco run on combined cycle which utilizes basically two types of fuels i.e. Liquid & Gaseous.The liquid fuels are:

• Furnace oil• High Speed Diesel Oil (HSD)

While Gaseous Fuel is purely the Natural Gas. Obtaining of the fuel:Liquid Fuel is obtained from two sources:

i) Pakistan State Oil (PSO)Pakistan State Oil is the major contractor for providing Low Sulphur Furnace Oil (LSFO) to Kapco. This FO is untreated and raw form. The oil reaches the plant through two ways:

2. Pipe Line from Mahmood Kot Oil Depot.3. Oil Tankers

Why LSFO is used at KAPCO?

Low sulphur Furnace Oil is used at Kapco Gas Turbines because these Gas Turbines have been designed for LSFO.LSFO contains less amount of sulphur the HSFO(High Sulphur Furnace Oil). Higher the amount of Sulphur in the fuel the more it contaminates the environment and high amount of sulphur cause various dangerous diseases. That is why KAPCO besides its designed considerations is IMS certified company which emphasizes on safety, environment protection along with quality production. So it uses LSFO to render minimum danger to the environment. The Stakes of Gas turbines are at lower heights because of very less sulphur exhaust as compared to the plants that use HSFO and their stakes are very high so that higher sulphur quantity coming out of them spread over large area and may not endanger seriously one concentrated region. Such plants are installed in Muzaffargarh and Lalpir.One more advantage of using LSFO is that its higher efficiency cause the machine units to run at peak speed within 4 to 5 minutes while HSFO units get top speed in one day or two because they use conventional boilers and HSFO.

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TREATMENT OF FURNACE OIL:

Treatment of LSFO is quite necessary before it can be used in the combustion chambers because it may contain a no. of impurities in the form of water soluble salts ,oil soluble salts and compounds, and suspended particles. These impurities can cause a considerable damage to combustion chambers, Turbine blades and other necessary equipment that are very expensive and these impurities thus lower the overall efficiency and increase the maintenance costs. Generally these impurities are classified in three types: . Water Soluble ( Na,K and other 2nd group elements)

. Oil Soluble (Pb, Ni , Co ,V etc) . Suspended particles and dust particlesNow there are different methods to remove these impurities. We first discuss the method to remove

water soluble impurities as follows:There are two methods to remove water soluble impurities from raw FO :

• Electrostatic Method• Centrifugal Method

There are five FUEL OIL TREATMENT PLANTS (FOTPs) at KAPCO for the treatment of Furnace Oil. FOTPs nos. 1, 2, 3 and 4 are for E no. 5 is for Centrifugal Method. Kapco is the only company that has the facility of removing water soluble impurities through Centrifugal method. Centrifugal Method is so far the most efficient method for the purpose.

1) Electrostatic Method In an electrostatic method basically the salts are ionized and made to collect at their respective electrodes. A large drum is used for this purpose in which there are cathode and anode.

Untreated FO is mixed with water in the drum at a specific temperature. The water soluble salts get mixed with water and +ive and -ive ions are formed. For example in case of NaCI two ions are formed i.e. Na+ & CI- When electrodes are connected to power supply of high voltage, these ions move to their respective electrode. Thus these salts are thus removed from the electrodes later on.Now a chemical called DEMULSIFIER is added into the oil+water mixture.The function of Demulsifier is to make the oil droplets separate from water droplets.It makes water droplets larger in terms of its diameter due to which its surface area increases and due to gravity water droplets settle down and drained to effulant water tanks. This water is called EFFULANT WATER. Thus this treated Oil is obtained and pumped to treated oil tanks.

An FOTP for electrostatic method generally comprises 7 sections:Storage and supply of treated and untreated OilPump and Heating System3-stage Electrostatic TreaterEffluent Water & Treating systemChemical Forwarding & Dosing SystemCompressed Air SystemsHeat Transfer Oil plant with sludge combustion and Handling

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Lubrication Oil System


2) Centrifugal Method:

In centrifugal Method, water is first added in Oil in the same way as before. Water soluble salts get dissolved in water and are separated from Untreated Oil. This water containing salts is removed from oil by centrifugal action. The water+Oil mixture is rotated at a very large speed in a large drum. The centrifugal force pushes the heavier fluid i.e. water containing salts in it towards outer radial direction and oil gets deposited in the centre and drained to Treated oil tanks .

Storage tanksThere are total no.of 27 tanks to store untreated FO, treated FO,HSD and effluent water. one tank has the capacity to store 8000cm3 oil. steam heating is carried out in tanks to keep oil temperature 80 c so that it can be easily flow through pipesThe distribution of oil tanks is as follows. For untreated oil, 11 tanks. For treated oil, 11tanks. For HSD, 5 tanks

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• The lubricating requirements for the gas turbine are furnished by a common forced-feed lubrication system. Lubricating fluid is circulated to the three main turbine bearings, generator bearings, reducing gear, accessory gear, as hydraulic oil in torque converter and also as control, trip oil, high pressure hydraulic oil & generator seal oil.

• Such a system must supply cool, clean and pressurized oil to bearing. This lub. system includes the following.

1. Lub. oil reservoir in the accessory base (12,490 liter)2. Main lub. oil pump (shaft driven from accessory gear).3. Auxiliary lub. oil pump4. Emergency lub. oil pump5. Auxiliary & emergency seal oil pump6. Lub. oil heat exchangers7. Lub. oil filters.8. Pressure relief valve VR1 in main pump discharge header (6.9)9. Bearing header pressure regulator VPR2-1 (1.7 bars)10. Mist Eliminator

Lubricating oil Pumps

• Main Oil Pump - positive displacement pump mounted on & driven by the accessory gear, rated 2725 lpm & 7 bar.

• Auxiliary Oil Pump - submerged centrifugal pump driven by AC motor (88QA-1), rated 2460 lpm & 7.5 bar.

o Higher pressure for torque converter during slow roll & start-up. Starts when speed dropbelow 14HS (90% rated speed) stop when turbine attains 95% rated speed.

Also when 63QA-1 sense a drop below 4.83 bar.• Emergency Lub. Oil Pump - submerged centrifugal pump driven by a DC motor (88QE-1).

Rated at 1590 lpm & 1.4 bar. Back-up for AOP when 63QT-2A & 2B below 0.55 bar.

Gas Turbine Maintenance

• Classification Gas Turbine Maintenance ;1. Standby Inspection2. Running Inspection3. Dis-assembly InspectionDis-assembly Inspection can be classified into :1. Combustion Inspection2. Hot Gas Path Inspection3. Major Inspection


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Generator


internship report of Kepco

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Transcript of internship report of Kepco