60361948 Gas Turbine Literature 9 PAGE

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GAS TURBINE - LITERATURE

HISTORICAL PROSPECTIVE OF GAS TURBINE:

In October 1791 idea of gas turbine was put by JOHN BARBER of U.K.,British patent

No. 1833. Dr. F. STULZE German scientist has developed GT with 0% efficiency. In between 1900-1906 1st GT of modern type was presented in paris,france,with continuous

combustion ,subsequently G.E. has started program on GT with actual engineering and

drawings. In between 1947-48 various capacity of GT have been put up in operation.1st

combined cycle plant of 3.5MW capacity was started in U.S.A. and in 1949 GT capacity

enhanced to 50 MW.

GAS TURBINE HISTORY OF INDIA

• 2*23 MW in 1965 April, at namrup ASSAM by ASSAM ELECTRICITY

BOARD.• First gas turbine in GUJARAT of 2*27 MW (FIAT DESIGN) was installed atDhuvaran in 1970 by G.E.B.

• Subsequently WEST BENGAL,URAN (MAHARASHTRA), DESU,J&K and NTPC central sector enter into gas turbine power generation field.

ENVIROMENTAL ASPECTS

Natural gas without any sulphar contents used as a fuel for gas turbine, leaving no SO-2

emission, suspended and other polluting element particles to atmosphere after combustion.

In comparison with fossil fuel power plant pollution, GT utility is more friendly to

environment.



INTRODUCTION

Energy of hot gases is converted in to work i.e. this conversion is taken place in nozzle

section of turbine. Gases are expanded and energy converted in to kinetic energy in buckets.

Turbine is also driving compressor, this compressor utilize 50% of energy for driving. Balance

out put will be useful work available at turbine flange which is connected to load.

Our is MS6001B series of GE make Model ,its firing temp is 2020F at base load .Heat rate is11120 BTU/KWh. Exhaust temp is 1017F.

BRAYTON CYCLE:

Invented by GEORGE BRAYTON.

1-2 = compression accured in compressor

2-3= Constant pressure heat addition in combustion chamber.

3-4= Expansion takes place in turbine.4-1=Constant pressure cooling process in turbine.

GAS TURBINE M.S. 6001B

Gas turbine of GE make Ms6001B frame VI single shaft ,heavy duty latest state of art in gas

turbine technology, whole package is supplied by BHEL.The MS6001B GT worksthermodynamically on BRAYTON CYCLE. It has three stages of turbine and 17 stages of axial

flow compressor connected directly with GT shaft, and 10 nos reverse flow combustion chamber

control on MARK IV.Speedetronic series of controls.Its primover is diesel engine of capacity

650hp.Natural gas is utilized as fuel at pressure 20 kg/cm2 and temp 120 c received from GAILat rate of 9900m3/hr for full load i.e. 30 mw .

SALIENT FEATURES:

1 Highly efficient



2. Heavy duty.

3. Best possible utilization and greater conservation of scare.4. low capital cost.

5. Requirement of less space.

6. Quick start of loading facility.

Generator unit is connected on same shaft through load gear, which reduced the turbine speedfrom 5100 rpm to 3000 rpm.

Gas turbine unit comprising following systems.

1. Starting device system.

2. Cooling water system.3. lubrication system

4. Hydraulic system

5. Air system

6. Fuel gas system7. Water wash system.

1. STARTING DEVICE:650 HP diesel engine is provided as prime mover which is directly connected with turbine

shaft with speed clutch arrangement. Its cooling water system is tapped off from IDCT Unit. On

execution of start command diesel engine will start and run on idle speed of about 700 rpm andgradually 20% speed achieved, thereafter gas control valve starts operating and ignition takes

place. In combustion chamber which further raised the speed to about 65% i.e. 3300 rpm. The

diesel engine cutoff and run for 5 minutes for uniform cooling of engine body.

2 COOLING WATER SYSTEM:

Cooling water system will perform cooling of following.

1 Generator air cooler 2 Lubrication oil cooler

3 Turbine lag cooling

4 Cooling water to diesel engine D M Water systemFor this 450 m3/hr capacity two no IDCT PUMPS are installed. Its cooling water

pressure is 2.5 Kg/cm2 over and above , tapping for this system is available from circulating

water inlet as stand by arrangement. In event of IDCT out of service. IDCT system has two pumps, one in running and another as stand by with auto changed facility on dropping of cooling

water discharge pressure is very low. Stand by pump will start within 12 seconds.

3 LUBRICATION OIL SYSTEM:

This system is fulfilled lubrication oil requirement to all bearings. Oil for trip oil ckt, i.e.control oil, starting device etc. System consist 6500 ltrs capacity main oil reservoir in base of

gas turbine with following auxiliary items.

a. Electrical driven auxiliary oil pump discharge oil pressure 4.6 kg/cm2 and 946

litres/minute oil flow.



b. D.C. emergency oil pump – D.C. supply driven pump on 125 V D.C. battery set is

provided, discharging pressure 4.6 kg/cm2 and 1741 litres/minute oil flow which isconnected directly on lubrication oil header by passing filter, cooler etc. This pump will

come in service at time of total power failure as backing protection.

c. Accessory driven MOP: This is very common system in high speed m/c. If force over

it function at 95% of speed. All lubrication oil requirement in running m/c will be full fill

by this arrangement.Lub oil at 1.8 kg/cm2 pressure used for all BRGS; suction for auxiliary

hydraulic pump & shaft driven hydraulic pump. Oil for starting device & rotatedoperation. Control oil, lub oil returns after performing its function back to MOT where

lubrication is cooled upto 50 C. by means of lubrication oil cooler.

4. AIR SYSTEM:

All requirement of air for GT m/c is fulfilled by 17 stage axial flow GT compressor.

Suction of GT compressor is taken from 384 nos.air filters (8x24raws) system provided air

requirement for following function.a. Seal air to turbine bearing nos 1 & 2.

b. Cooling air to internal parts of buckets, nozzles.c. Cooling air in turbine outer shell & exhaust frame.d. Control air for air operated valves.

e. Duloe air to self cleaning system of air filters.

Air extraction from gas turbine compressor & its service

5th stage extraction :- for bearing sealing. This air is filtered and cleaned by air separator to provide dirt free air for BRGS.

11th stage extraction : Tapped from four points radially for bleed system.

16th stage extraction : This is used as cooling air for GT internal cooling air through centre of

turbine bore, is forced for cooling of 1st and 2 nd stage turbine buckets as well as after phaseof second stage wheel.

-forward stage of third stage wheel-forward side of 1st and 2nd stage nozzle

-forward side of second stage wheel.

AIR PROCCESING UNIT

Quality of air drawn form atmosphere by GT compressor is of prime importance air

contaminants like, dust, dirt ,smoke vapor, fog, particles are normally found

Such contaminants can cause erosion and corrosion and fouling of compressor blades. Thisfurther lead effect on compressor efficiency which can promote even erosion and corrosion of

turbine blades too, as some quantity of air is being used in GT as cooling media.

Air used in GT should have qualitative control. Air borne contaminanents is very harmful; so

for removal of such particle matters air filters banks are provided in 8*24 raws; two tier

viz.top/bottom. In this unit Automatic Reverse Jet self cleaning arrangement is made. For this



pressurized air is utilized from last stage of the GT compressor. For removal of the large particle

pre filter arrangement is introduced, which proved to be extend the life of the main filter. In thissystem indicating filter element choking. Air DP measurement across filter box is provided

which extend alarm at 150 mm of water column i.e. 6” WCL and shutdown machine if DP

reaches 200mm WCL i.e. 8”WCL

(05)FUEL GAS SYSTEM:

Natural gas is used as fuel at pressure 20 kg/cm2 and temperature 120degree Centigrade.Before entering gas in GT fuel system. All liquid condensate is removed at gas conditioning

skid. Hydraulically operated valve and gas control valve are provided.

(06) HYDRAULIC OIL SYSTEM:

It required for operation of gas ratio and gas control valve and IGV actuator. This system

provides 80 kg/cm2 oil pressure which is developed by means of electrical driven auxiliary.

Hydraulic pump (88 HQ), shaft driven MHOP. At 95% of machine MHOP is taken over. Oilsupply function of hydraulic system suction of both pump are tapped from lubrication oil header

line.

(07) COMPRESSOR WATER WASH SYSTEM:

Even though micro filters are provided to filter air and removal of air borne particles matter, air

will carry some particles which accumulate on compressor blade which leads to lower compressor efficiency ultimatelly, resulting in lower load operation. The compressor is required

to be cleaned by water washing arrangement system consisting one w/w pump, and one detergent

pump with sufficient quantity bearing their tanks. Washing is taken on hand during shut down.

Operation sequence: (for water washing)

a. shut down m/c and cooled up to 80 c when space temp reached. b. fill the tank fully by 80 c feed water

c. fill detergents tank 100 lit of “ CASTROL GT CLEAN”

d. m/c is made ready to start.e. Isolation of valve ,opening of valve as mention in separated sheet.

F. start IDCT and CW system for cooling.

g. select “OFF LINE WATER WASH ON” in MARK IV.h. start on cranking mode.

i. observed and ensure IGV is full open.

J). start w/w pump and ensure water flow is established in system.

k.) stop w/w pump.l.)start detergents pump ,keep running till 100 lit detergents used.

m. stop m/c for soaking for 10 minutes .

n)..restart m/c on opening of IGV.water wash is started keep running till clear water isobserved from w/w drain line.

o) stop m/c.

p)all valve position make normal and isolation for water wash may be removed. After cleaningfrom TMD.

Start m/c on cranking .20 min for drying it there after auto command may be given and

synchronized, observed abnormal noise, vibration .



Both parameter before and after water washing may be recorded and compared.

GAS TURBINE AUXILARY AND LOAD.

Sr. No

Auxiallryequipment

Installedkw

Runningm/c KW

Function

01 Load gear compartmentVent fan VG1

VG2

VG3

2

2

0.37

2

2

0.37

Hot air ,oil vapour,

Exhaust in Atmospher

02 Turbine acc. Gear

compartment

vent fan BT1BT2

5.55.5

5.55.5

Ventify of turbine acc gear

compartment

03 Exhaust frame blower fanTK1

TK2

37

37

37

37

To cool turbine shell

04 Auxiliary oil pump (AOP) 37 - Provide lub oil/hydraulic

oil charging.

05 Auxiliary hydraulic pump 2.25 - Starting of m/c

06 IDCT A

B

55

55

55

-

Cooling water for

DE,LOC,GENAC,legcooler

07 CT FAN 30 30 Hot air and vapour vent outto atmosphere from IDCT

sump top basine.08 Emergency oil pump 7.5 kw - At event of total power

supply failure provides lub

oil requirement to brgduring cooling down and

ratchet operation.

START-UP CHECK PERMISSIVES (as per mark 4 control)

1) Turbine is stopped.

2) Lub oil temp. normal.3) Over speed bolt is not tripped.4) Vibration sensor input is enable.

5) No Flame exists.

6) Control is not off.

7) Compressor bleed valve is open.(Both)8) Inlet guide vanes are closed.

9) Brg. Seal air valve is open.

10) Fuel lockout valve is reset.

60361948 Gas Turbine Literature 9 PAGE

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