The analysis of a mixed steam-gas aero derivative turbine

44 Pages·2015·1.28 MB·English

UNIVERSITY OF TWENTE
BACHELOR ASSIGNMENT FOR ADVANCED TECHNOLOGY
FINAL REPORT
The analysis of a mixed steam-gas aero derivative
turbine
Bachelorcommittee:
Author: Dr. Ir. J.B.W.Kok
AlexanderHaselhoff,s1120891 Prof. Dr. Ir. A.deBoer
Dr. S.Vanapalli
July2,2015

Abstract
An analysis is done by the use of thermodynamics for an aero derivative gas turbine which utilizes steam injection to
increase its efficiency. This type of cycle is known as the steam injected gas turbine cycle. The main purpose of this
researchwastodevelopabetterunderstandingofhowoptimalcycleefficiencyisreached,forwhichthesteamofinjection
isgeneratedbyuseoftheturbineexhaustheat.
AmodelhasbeendevelopedusingthesoftwareEngineeringEquationSolvertosimulatethesimplegasturbine,steam
generation and effects after steam injection. Input parameters for the model are taken for the GE LM6000 turbine as
provided by General Electric. Turbine property results are compared with literature for validation and show the same
characteristicbehaviour.
Severalparameterinfluencesarevisualizedandexplained.Ithasbeenfoundthatthistypeofcycleshowsaveryspecific
point where the efficiency is the highest. By using steam injection for the chosen turbine and parameters an efficiency
gainsofaround11%andpoweraugmentationof45%ispossibletobeachieved.
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Contents
Abstract 3
Listoffigures 7
Listoftables 7
Nomenclature 9
1. Introduction 11
1.1. Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.2. Previousstudiesandperspectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
1.3. Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2. Theory 13
2.1. Theidealgasturbine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.2. Idealandactualcycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.3. STIG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2.4. OTSG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.5. Enginechoiceandparameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3. EESmodel 19
3.1. SimpleGTmodel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3.2. STIGmodel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3.3. OTSGmodel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4. Analysis 23
4.1. Verificationwithliterature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.2. STIGefficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5. Discussion 27
6. Conclusionsandrecommendations 29
A. Simplegasturbine 33
B. STIG 37
C. OTSG 41
D. Completemodelsolutions 43
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List of Figures
2.1. Braytoncyclevisualized. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.2. Schematicoverviewofasimplegasturbine. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.3. SchematicoverviewoftheSTIGsetup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2.4. SchematicoverviewoftheOTSG. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.1. SchematicoverviewoftheEESmodel.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.1. SimpleGTspecificworkandefficiencyforgivenP-ratiosatTIT =1200,1300,1400◦C. . . . . . . . . 23
4.2. STIGspecificworkandefficiencyforgivenP-ratiosatTIT =1200,1300,1400◦C. . . . . . . . . . . . 24
4.3. STIGspecificwaterconsumptionandoptimalsteamfractionatP-ratiosforTIT =1200,1300,1400◦C. 24
4.4. Highestpossiblesteamtemperatureforcertainmass-fractionx . . . . . . . . . . . . . . . . . . . . . . . 25
4.5. STIGefficiencyforcertainamountofinjectedsteamx. . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.6. TurbineoutlettemperatureandoptimalsteamfractionxforcertainpressureratioatgivenTIT. . . . . . . 26
List of Tables
2.1. ManufacturerdataLM6000-PG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.1. Modelparameterassumptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3.2. ManufacturerdatacomparedwithsimpleGTmodelresults . . . . . . . . . . . . . . . . . . . . . . . . . 20
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Nomenclature
Abbreviations
CC combustionchamber
EES engineeringequationssolver
GT gasturbine
PR pressureratio
SF steamfraction
STIG steaminjectedgasturbine
TIT turbineinlettemperature
Symbols Unit
c specificheatcapacity kJ/kgK
η efficiency -
h enthalpy kJ/kg
LHV lowerheatingvalue kJ/kg
m˙ mas-flow kg/s
s entropy kJ/kgK
W˙ work kJ/s
w specificwork kJ/kg
Q˙ heat kJ/s
q specificheat kJ/kg
T temperature K or◦C
Subscripts
a air
amb ambientcondition
eco economizer
c compressor
cc combustionchamber
f fuel
g combustiongas
is isentropic
p pressure
s steam
sh superheated
t turbine
vap evaporation
w water
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