gas turbine operation and maintenance operation, performance and maintenance gas turbine chapter 1...
TRANSCRIPT
OPERATION, PERFORMANCE AND MAINTENANCE
Gas Turbine
CHAPTER 1
Introduction to the gas turbine engine
Gas Turbine Engine Classification I- Industrial Gas Turbine II- Air craft Gas Turbine
• Aircraft propulsion,• Oil and gas pipeline pumping• Offshore platforms• Utility power generation• Ship propulsion • Equipment Prime mover
Major gas turbine implementation
CHAPTER 2
Energy transmission in gas turbine engines
CHAPTER 3
Fluid flow in gas turbines
Air in the compressor stages. How pressure builds up through the compressor stages. Flue gas in the turbine stages. Air in the combustion chamber
CHAPTER 4 Gas turbine engine performance and specifications
1- Code and Standards2- performance and specifications
CHAPTER 5
CHAPTER 6
Selected topics on gas turbine component design
Maintenance of gas turbines
CHAPTER 7
Miscellaneous
• Gas Turbine Thrust balance• Dry gas seal system• Gas Turbine Thrust balance• Dry gas seal system• Bearings
As a result, the specific fuel consumption of the turbo-machine has been reduced and thrust to weight ratios have increased.
Preface
The aircraft gas turbine engines test ran and produced thrust for the first time in 1937.
After 1945, aircraft gas turbine development efforts have been directed towards increasing pressure ratios, turbine inlet temperatures, component efficiencies, bypass ratios, reliability and durability.
The turbo-machine is now one of the worlds most important prime movers.
The first jet engine developed only a few hundred pounds of thrust, while the latest generation of engines exceed 100,000 pounds thrust.
The engines for the land-based power plants exceed 250MW in power output.
* Major gas turbine implementation
• Aircraft propulsion,• Oil and gas pipeline pumping• Offshore platforms• Utility power generation• Ship propulsion • Equipment Prime mover
* Gas Turbine Engine Classification
I- Industrial Gas Turbine
II- Air craft Gas Turbine The output can range from 100% thrust or essentially all shaft power
The output is the all shaft power
A- Turbo propeller All of the power output is used to turn the propeller shaft. a gear box is used between the engine and propeller
B- Turbofan The power output is split between thrust and power to turn the fan which comes after the compressor.
C- Turbo Jet All of the power output is used in a form of thrust
I- Industrial Gas Turbine
DIFFUSER
AIR COMPRESSOR
AIR INLET
COMBUSTOR
GAS GENERATOR TURBINES
EXHAUST
A- Turbo propeller
Turbine
Combustion chamber
CompressorPropeller
II- Air craft Gas Turbine
All of the power output is used to turn the propeller shaft.
B- Turbofan
TurbineCompressorFan Exhaust
1- power to turn the fan
The power output is split between
2- Jet thrust
Turbine Wheel
Compressor Wheel
Compact type GT.
AIR OUT
Combustion Chamber
FLUE GASES
EXHAUST
AIR IN
Power distributionPower distribution
COMBUSTION CHAMBER
COMPRESSOR
20 MW
FUEL
35 MW
20 MW HOT AIRCOLD AIR
35 MW
EXHAUST
25 MW
TURBINE
LOAD
10 MW
55 MW
Assuming 100% Efficiency
Exhaust70%
Mechanical power28%
Sankey diagram
Fuel Input100%
Radiation& Mechanical losses2%
Turbine Power
Compressor Power
Gas Turbine Combined Cycle
Generator
COMPRESSOR TURBINE
Hot Gas
BOILER
STEAM
STEAM TURBINE
GeneratorGenerator
FLUIDS FLOW KINAMATIC ENERGY
v2 < v1 P2 > P1
P1
P2
+2 g
V22 P2
+2 g
V12 P1 CONSTANT
Thermal energy Plus
TOTAL ENERGY DIMENTIONS
2V2g
ft2
sec 2
ft2sec
= ( ft )=ft
2
sec
ft2sec
=
P
density
ft 3
2ft= ( ft )=
Lb
Lb
2
ft 3
ft=
AIR IN COMPRESSOR STAGES
AIR IN COMPRESSOR STAGES
FIXED
STATOR BLADES
FIXED
STATOR BLADES
COMP.BLADES
MOVING
AIR IN COMPRESSOR STAGESAIR IN COMPRESSOR STAGES
FIXED
STATOR BLADES
COMP.BLADES
MOVING FIXED
STATOR BLADES
X
XY1
Y2
STATOR BLADES ACT AS DIFFUSER
AS Y2 > Y1
AIR PRESSURE THROUGHCOMPRESSOR BLADES
HAS NO CHANGE
AS X = X
STATOR BLADES ACT AS DIFFUSER
FIXED
STATOR BLADES
FIXED
STATOR BLADES
VOLUME INCREASED
HOW PRESSURE BUILDS UP IN COMPRESSOR STAGES
HOW PRESSURE BUILDS UP IN COMPRESSOR STAGES
PRESSURE INCREASED
VELOCITY (IN STATOR ) DECREASED
VELOCITY (IN MOVING ) INCREASED
VELOCITY IS CONSTANT ALONG THE COMPRESSOR
V inlet = V outlet
VELOCITY IS CONSTANT ALONG THE COMPRESSOR
V inlet = V outlet
COMP.BLADESMOVING
Velocity
Pressure
Rotor Stator StatorRotor
Axial Flow Compressor Pressure
Stator
Constant Velocity
Pressure increased
TURBINEBLADES
MOVINGFIXED
STATOR BLADES
FIXED
STATOR BLADES
FLUE GASES IN GAS
TURBINE.
FLUE GASES IN GAS
TURBINE.
TURBINEBLADES
MOVINGFIXED
STATOR BLADES
FIXED
STATOR BLADES
FLUE GASES IN GAS
TURBINE.
FLUE GASES IN GAS
TURBINE.
STATOR BLADES ACT AS NOZZELS
VOLUME INCREASED
HOW POWER GENERATES IN GT. STAGES HOW POWER GENERATES IN GT. STAGES
PRESSURE DECREASED
VELOCITY DECREASED
TEMPERATURE DECREASED
STATOR BLADES ACT AS NOZZELSTHE FLUE GASES VELOCITY ENERGY WILL BE TRANSFERED TO TURBINE BLADES
ENERGY PARAMETERS THROUGH THE TURBINE INLET AND OUTLET WILL BE :
AIR THROUGH COMPRESSOR STAGESAIR THROUGH COMPRESSOR STAGES
3- TEMPERATURE INCREASED
1- PRESSURE INCREASED
2- VELOCITY CONSTANT
4- VOLUME DECREASED
A
AIR THROUGH COMBUSTION CHAMBERSAIR THROUGH COMBUSTION CHAMBERS
1- PRESSURE CONSTANT
2- TEMPERATURE INCREASED
3- VOLUME INCREASED
B
FLUE GASES THROUGH TURBINE STAGESFLUE GASES THROUGH TURBINE STAGES
1- PRESSURE DECREASED
3- TEMPERATURE DECREASED
4- VOLUME INCREASED
2- VELOCITY DECREASED
C
* Code and Standards
API RP 11PGT Recommended Practice for Packaged Combustion Gas Turbines
API STD 616 Gas Turbines for Petroleum, Chemical, and Gas Industry Services
Back-up Lube Oil Pump started
START COMMAND
Supply Lube Oil to :• Turbine• Gear box• Generator bearings• Accessory driver
Turbine driven L/O Pump starts as Engine rotates
15% to 20% Ngp
Purge
Ignition CommandFuel valve opened
Commence Rotation
65% Ngp• Starter Drop out• Main L/O Pump supply all pressure• Back-up Lube Oil Pump stopped
83 % NgpBleed ValveFully closed
Ngp
Per
cen
t
Elapsed time
100% Ngp 75% Ngp• Variable Guide vanes start to open• Bleed Valve start to close
General System Operational
SequenceSingle shaft
Generator Set
General System Operational
SequenceSingle shaft
Generator Set
43
IN CASE OF GAS TURBINEAIR COMPRESSOR SURGE BLEED VALVE WILL OPEN
IN CASE OF GAS TURBINEAIR COMPRESSOR SURGE BLEED VALVE WILL OPEN
COMPRESSOR TURBINE
BLEED VALVE
SIMPLE CYCLE P-V DIAGRAM OF G.T.SIMPLE CYCLE P-V DIAGRAM OF G.T.
P
ATMS
V1
CO
MP
RE
SSION
4
TU
RB
INE
(EX
PAN
SION
)
32COMBUSTION
WHY GAS TURBINE CONSIDERED AS
A THERMAL POWER ENERGY MACHINE
WHY GAS TURBINE CONSIDERED AS
A THERMAL POWER ENERGY MACHINE
1- COMPRESSION STAGE
Wc = m * Cp ( T2 – T1 ) KW
2- COMBUSTION STAGE
Q f = m * Cp ( T3 – T2 ) KW
3- TURBINE POWER STAGE
Wt = m * Cp ( T3 – T4 ) KW
W c = Compressor power kw
W t = Turbine power kw
Q f = Fuel produced power kw
m = Air mass flow kg/sec.
Cp = Specific heat kj/kg.
T = Absolute Temperature
0k0k
GAS TURBINE POWERGAS TURBINE POWER P
ATMS
V
1C
OM
PR
ESSIO
N
4
TU
RB
INE
(EX
PAN
SION
)32
COMBUSTION
=Wt - Wc
Q fξ
0
OUTPUT
INPUT* 100= * 100
( T3 – T4 ) – ( T2 – T1 )
T3 – T2= * 100
OVERALL EFFICIENCY ξT
( T3 –T2) – (T4 – T1 )
T3 – T2= * 100
ξT
= 1 – ( T4 – T1 )
( T3 – T2 )ξ0
To improve
* EXHAUST TEMP. T4 TO BE AS LOW AS POSSIBLE
* FIRING TEMP T3 TO BE AS HIGH AS POSSIBLE
* COMP.OUT.TEMP.T2 TO BE AS LOW AS POSSIBLE
* T2 - T1 to be considered
EXAMPLEFIND THE Turbine EFFICIENCY OF G.T HAS THE FOLLOWING DATA: -
1 – AMBIENT TEMPERATURE = 20 C
2 – FIRING TEMPERATURE = 950 C
3 – EXHAUST TEMPERATURE = 490 C
4 – COMP. OUT TEMPERATURE = 300 C
O
O
O
O
T1 = 20 + 273 = 293 K
T3 = 950 + 273 = 1223 K
T4 = 490 + 273 = 763 K
T2 = 300 + 273 = 573 K
O
O
O
O
ξ0
= 1 – ( T4 – T1 )
( T3 – T2 ) ξ0
= 1 – ( 763 – 293 )
( 1223 – 573 )
ξ0
= 1 – ( 470 )
( 650 ) ξ0
= 1 – ( 0.72 )
ξ0
= 0. 28 = 28%
EXAMPLE
FIND THE OVERALL EFFICIENCY OF G.TURBINE HAS THE FOLLOWING DATA: -
1 – AMBIENT TEMPERATURE T1 = 12
2– COMP. OUT TEMPERATURE T2 = 200
3 – EXHAUST TEMPERATURE T3 = 950
4– FIRING TEMPERATURE T4 = 340
1- T1 = 20 + 273 = 293 K2- T2 = 300 + 273 = 573 K3- T3 = 950 + 273 = 1223 K4- T4 = 490 + 273 = 763 K
( T4 – T1 )( T3 – T2 )
( 763 – 293 ) ( 1223 – 573 )
ξ = 0.56
1 – =ξ
1 – =ξ