GT Various Systems(G)

7/30/2019 GT Various Systems(G)

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Starting System

Oil system Fuel System

Cooling Water system

Cooling and Sealing Air system Fire Protection system

Ventilation and heating system

Leak Detection system

Wet Washing system


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GAS TURBINE AT KGPP KAWAS

TECHNICAL SPECIFICATION

VARIOUS SYSTEMSGT STARTUP AND SHUTDOWN


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Introduction to Gas Turbine


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Gas Turbine is a heat

engine

The Process Includes

Compression :

of working medium (air) taken

from atmosphere in acompressor

Combustion

Increase of working medium

temperature by constantpressure ignition of fuel in

combustion chamber

Expansion

of the product of combustion in

a turbine.


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The Ideal Thermodynamiccycle

The working of Gas Turbine isbased on Joule Brayton Cycle.

A typical cycle consists of tworeversible isobars and tworeversible adiabatic process

Ideal Cycle Efficiency of BraytonCycle is given below

Thermal Efficiency = =

1-1/ (p)v-1/v

Where p= Pressure Ratio.

v= Adiabatic Constant.

So ideally, Thermal Efficiency of aBrayton Cycle is dependent on

Pressure ratio of the cycle.


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The Actual Thermodynamiccycle

For all practical reasons the

actual thermal efficiency will

depend on

Pressure ratio

Turbine inlet Temp

Compressor inlet temp

Efficiency of Compressor and

Turbine


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Applications of Gas Turbine

Conventional applications are Simple cycle operation.

Combined cycle operation.

Co-generation.

Electric utility companies use gas turbinepredominantly in simple cycle and combinedcycle applications. Industrial Company uses them

as co-generation power plants


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A Brief History of Gas Turbines

First industrial duty gas turbine of 4 MW was developed byBrown Beaver in 1939 with open cycle efficiency of 18%.

The development in the science of aerodynamics andmetallurgy significantly contributed to increased compressionand expansion efficiency in the recent years.

At Kawas, the Gas Turbine are GE make (Model 9E)

31% open cycle efficiency

49% combined cycle efficiency

Today gas turbine unit sizes with output above 250 MW at ISOconditions have been designed and developed. Thus theadvances in metallurgical technology have brought with a goodcompetitive edge over conventional steam cycle power plant.


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Advantages of gas turbine w.r.t steam turbineare:

1. Fast to start

2. Low Installation cost due to Standardization andModularization.

Low installation cost owing to standardization, factory

assembly and test. This makes the installation of the station

easy and keeps the cost per installed kilowatt low because

the package power station is quickly ready to be put in

operation.

Due to modular approach they are relatively easy and fasterto install.

Package concept makes easier shipping, handling, becauseof its robustness

3. Low standby cost:

fast start up and shut down reduce conventional stand bycost.

The power requirements to keep the plant in standby

condition are significantly lower than those for other types ofrime movers.


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Advantages of gas turbine wrt to steamturbine cont..

4. Low capital cost.

Fewer Auxillaries

Benefits of low capital costs were initially offset by higheroperating costs when compared with other installedcapacities. Therefore earlier gas turbine was strictly for peak

load operation. Improvements in efficiency and reliability andapplication of combined cycle operation have addedeconomic benefits to the gas turbine based power plants.

5. Maximum application flexibility:

The package plant may be operated either in parallel withexisting plants or as a completely isolated station. Theseunits have been used, widely for base, peaking and evenemergency service. The station can be equipped with remotecontrol for starting, synchronizing & loading


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Advantages of gas turbine wrt to steamturbine cont..

5. Control reliability:

the microcomputer based control, with an integratedtemperature system (ITS) provides accurate control, quickprotection and complete sequential start up & shut down &

operation.


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Gas Turbine plant Layout


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Gas Turbine Auxiallaries Layout


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Starting System

Before the gas turbine can be fired and

started It must be rotated or cranked by the

accessory equipment.

This is done by an induction motor,operating through torque converter to

provide cranking torque and speed

required by the turbine for start-up. The starting system consists of an

induction motor and torque converter

coupled to the accessory gear.


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Torque Converter

The starting motor drives the torque converter

input through a flexible coupling. The torque converter output is coupled to the

accessory gear and provides the required

torque multiplication for the starting motor to

drive the turbine.

The main parts of torque converter are the

impeller driven by the input shaft, the turbine

wheel, which drives the output shaft, and thestator, which directs fluid from the impeller to

the turbine at the correct angle to produce the

required output torque.


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ACCESSORY DRIVE

The accessory drive gear, located at thecompressor end of the gas turbine, is a

gear assembly coupled directly through

a flexible coupling to the turbine rotor.

Its function is to drive each gas turbine

accessory at its proper speed. Inaddition, it contains the system main

lube oil pumps and the turbine over

speed bolt mechanism.


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Oil System

Lubricating fluid is circulated to :

Three main turbine bearing Generator bearings,

The turbine accessory gears and fuel pumps.

The starting means torque converter for use as

hydraulic fluid as well as for lubrication. After pressurization oil is diverted and filtered

again for use by hydraulic control device ascontrol fluid.

The trip circuit as trip oil system

Lub Oil

Hydraulic Oil

Trip Oil


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Lubricating oil system

Major system components include:

Lube reservoir in the accessory base

Main lube oil pump (shaft driven from the accessory

gear) Auxiliary lube oil pump and emergency lube oil

pump

Pressure relief valve VR-1 in the main discharge

Lube oil heat exchangers

Lube oil filters

Bearing header pressure regulator VPR-2


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Hydraulic oil system

The main hydraulic supply system utilizes

turbine lube oil to supply the high-pressure

fluid for operating fuel control valves, or other

devices Gas Fuel Stop valve and control valve

Liquid fuel stop valve and control valve

IGV control


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Trip Oil system

Some protections are strictly for abnormal andemergency operating conditions requiringshutdown of the turbine.

The hydraulic trip oil is the primary protectioninterfacebetween the turbine control protectionsystem circuits (SPEEDTRONIC control system)and the component, which admit or shut off fueland regulate IGV position.


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FUEL SYSTEM

GAS FUEL SYSTEM

LIQUID FUEL SYSTEMATOMISING AIR SYSTEM

Gas Fuel System


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Gas Fuel System

The gas fuel system is designed to deliver gas fuel

to the turbine combustion chamber at the proper

pressure and flow ratesto meet all of the starting,

acceleration and

loading requirements of gas turbine operation


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The following major components comprisethe gas fuel system:

Strainer Fuel gas supply pressure alarm switch

Gas stop ratio valve VSR

Gas control valve VGC

Stop ratio LVDTS 96GC-1, 2

Stop ratio valve-control servo valve 90SR

Gas control valve- control servo valve 65 GC

Gas fuel dump valves VH5 and VH12 Gas fuel vent solenoid valve 20 VG-1 and 2

Pressure gauges

Lines to the 14 combustion chambers


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Liquid Fuel System


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Liquid Fuel SystemThis liquid fuel control system is made up of fuel handingcomponents and electrical control components.

It includesfuel supply strainer SF1,fuel oil stop valve VS1,hydraulic trip valve VH4,

fuel pump PFI ,fuel bypass assembly, fuel pump pressure relief valve VR4,high and low pressure fuel filters,flow divider FD1,combined selector valve/pressure gauge assembly,check valve VCK1-1 to14,false start drain valve VA17-1, -2, -5.

The electrical control components are:fuel oil stop valves limit switches 33 FL-1, -2,liquid fuel pump bypass valve servo valve 65 FP,liquid fuel bypass valve position feedback LVDT 96FP-1, -2,flow divider speed pickups 77FD-1, -2


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Atomizing Air System


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Atomizing Air System

Atomising air system provides sufficient pressure inthe air atomising chamber of the fuel nozzle body

to maintain the ratio of atomising air pressure tocompressor discharge pressure at approximately 1.2 or

greater over the full operating range of the turbine.

Since the output of the main atomising aircompressor, driven by the accessory gear, is low atturbine firing speed, during starting, booster atomisingair compressor provides a similar pressure ratioduring the firing and warm up period of the startingcycle and during a portion of the accelerating cycle


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COOLING AND SEALING AIR


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COOLING AND SEALING AIRSYSTEM

The cooling and sealing air system providesthe necessary airflow from the gas turbinecompressor

to other parts of the gas turbine rotor andstator

to prevent excessive temperature build-up inthese parts during normal operation and

sealing of the turbine bearings. Air from two centrifugal type blowers isused to cool the turbine exhaust frame. Thesetwo fans are part also the part of cooling

system.

COOLING AND SEALING AIR


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COOLING AND SEALING AIRSYSTEM

Cooling and Sealing functions provided bythe system are as follows:

Sealing of the turbine bearings

Cooling of internal turbine parts subjected to

high temperature.

Providing an operating air supply for air

operated valves.


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Bearing cooling and sealing.

Cooling and sealing air is provided from the fifthstage and is piped to each of the three turbine

bearings.

Orifices in the airlines to the turbine bearing limitthe flow of air and the pressure to the proper value.

The pressurized air-cools and seals the bearing by

containing any lubrication fluid within the bearinghousing that otherwise might pass to the mechanicalseals.

Air is directed to both of each bearing housing for

providing a pressure barrier to the lubricating fluid. After performing this function, the air is vented via

the oil drain passage from the bearings No.1 andNO.3 while air from the bearing No. 2 is vented to

atmosphere.

E h t f d t bi h ll li


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Exhaust frame and turbine shell cooling

Two electric motor-driven, centrifugal blowers(88 TK-1 and 88 TK-2) are mounted external to

the turbine for cooling of the exhaust frame andturbine shell.

Pulsation Protection The pressure, speed and flow characteristics of

the gas turbine compressor are such that airmust be extracted from the 11th stage andvented to the atmosphere to prevent pulsationof the compressor during the acceleration

period of the turbine starting sequence andduring deceleration of the turbine at shutdown.Pneumatically operated 11th stage airextraction valves, controlled by a three-way

solenoid valve, are used to accomplish theulsation function.


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GT COOLING WATER SYSTEM

The cooling water system is a pressurisedclosed system

For heat dissipation requirements of

the lubrication system,the atomising air system andthe turbine support legs.

During frost the cooling system must be filled with anaqueous solution of ethylene glycol.


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FIRE PROTECTION SYSTEMThe carbon dioxide (CO2) fire protection system

to extinguish fires by reducing the oxygen content ofthe air in the compartment from an atmosphere

normal of 21 percent to less than 15 percent which is

insufficient concentration to support the combustion

of turbine fuel or lubricating oil.

System design is designed recognizing the reflash

potential of combustibles exposed to high

temperature metal;

it provides an extended discharge to maintain an

extinguishing concentration for a prolonged period to

minimize the likelihood of a reflash condition.


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Major system components include: Carbon dioxide cylinder, (in and off- base station),

discharge pipes and nozzles, pilot valves, firedetectors and pressure switches

Zone 1: Turbine accessory compartment and turbinecompartment

Zone 2: Tunnel of bearing no. 3

Zone 3: Generator

Two types of discharge are used: initial dischargeand extended discharge

FIRE PROTECTION SYSTEM


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The initial discharge must permit a rapiddischarge of CO2 to quickly build up anextinguishing concentration.

The extended discharge is smaller andpermits a relatively slow discharge rate inorder to maintain the extinguishingconcentration over a prolonged period oftime. By maintaining the extinguishingconcentration, the likelihood of a fire

reigniting is minimized.

FIRE PROTECTION SYSTEM


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VENTILATION SYSTEM


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VENTILATION SYSTEMVentilating capabilities have been incorporated in the turbine and

accessory components (enclosures), by utilizing thermally insulatedside panels and roofs

The three compartments, accessory, turbine and load shaft are,independently ventilated

Gravity operated dampers are used in the system to automatically

provide an enclosure when the protection system is activated

The gravity closing dampers are normally held open by thepressure- operated latches, which must be manually reset afterdamper release.


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GAS TURBINE OPERATIONS


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System Line Up

What is System Lining Up?

What if I fail to line up the

system ?What are the systems to be

lined up ?


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System Lining Up

It is a process of checking

all the auxiliary system along with its

equipments

pipings, valves, control instruements , tanklevels,

Filters , Heat exchangers, pumps, motors

etc

Power and control supply


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What if I fail to line up the

system ?Failure to Start

Equipment distressSafety Concern

Inefficient Operation

What are the systems to be lined


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What are the systems to be lined

up

Starting System Oil system

Fuel System

Cooling Water system Cooling and Sealing Air system

Inlet air Filteration system

Fire Protection system

Ventilation and heating system

Leak Detection system


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Starting a Gas Turbine

Turning GearCranking

Venting/purging

FiringWarm up

Acceleration

Full speed No Load

Synchronization

Loading


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Time

1

2

3

4

0

0-1 Cranking

1-2 Purging

2-3 Speed down to firing speed

3- Firing

3-4 Warm up4-5 Acceleration

5-6 Full Speed no load

5 6

Torque converter angle

Fuel

Speed

Turning Gear Operation


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Turning Gear Operation

In Turning Gear Operation the whole

shaft-line is rotated at 3.3 % speed(100) rpm

During starting after a long shutdown

During Shutdown , to provide uniform

and gradual cooling of the rotor,statorand combustion chamber equipment to

prevent shaft bowing and decrease

thermal stresses

C ki O ti


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Cranking Operation

In Cranking Operation the shaftline isrotated at 25% speed (600) rpm


For Special Operation like

Wet Washing Heavy Purging

Fi i O ti


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Firing Operation

In firing Operation shaftline is rotated at

firing speed 18% with fuel firing on


To Check parameters evolution during

startup

AUTO OR REMOTE


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AUTO OR REMOTE

GAS TURBINE READY TO START PERMISSIVES

Any of the above No

NOT READY TO

START

All yes

START ORDER

AUTO VENT CLOSE

AOP START

LUB OIL PRESSURE

NORMAL

JACKING OIL PUMP START

Ready To Start

GT WATER PUMP START SUPER PACKAGE FAN START 88 BT

1 -No lube Oil pressure low trip

2 -Jacking oil pressure OK

3 -Super package vent complete

4 -Jacking oil pump motor run

AAll Yes

A


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CRANKING MOTOR STARTHYD. OIL PUMP START TORQUE CONVERTOR AT

MAX 65%

A

SPEED INCREASE 14 HT

(8.4%)

TORQUE

CONVERTOR 50%

OIL MIST SEPERATOR

START

SPEED INCREASE 14 HM (10%)

SPEED DECREASES

TURBINE PURGING (1 min)

PURGE TIMER PICK UP

TORQUE CONVERTOR 15%

JACKING OIL PUMP STOP

EXHAUST COOLING FANMOTOR START 88 FX

SPEED DETECTED 14 HR (0.06%)

SPEED INCREASE TO

VENT SPEED


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SPEED DOWN to FIRING SPEED

FSR FIRING LEVEL (19. 8%) SPARK PLUG 1 min

FLAME DETECTION 2 OUT OF 4

GT COOLER FAN 1-6

START

2 SEC LOAD COMPT. FAN 88VG

EXHAUST FAN 88TK1,2

START

TORQUE

CONVERTOR 65%

FSR TO WARM UP LEVEL

(9.5%)

FSR & SPEED INCREASE

SPEED 60% 14 HC

CRANKING MOTOR

STOP

GEN WATER PUMP START

GEN FIN FANS START


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SPEED 95% 14 HS

AOP STOP AUX HYD OIL PUMP

STOP

GEN EXCITATION ON

COMPRESSOR BLEED VALVES

CLOSE

SPEED SET POINT 100.3% SYNCRO ON AUTO

Yes

VOLTAGE

MATCHINGSPEED MATCHING

GEN CIRCUIT BREAKER CLOSE

IF NO LOAD

SELECTION

SPINNING RESERVEGT COOLING FANS

START

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GT Various Systems(G)