Advanced Gas Turbine Cycles Episode 12 docx

gas turbine efficiency has produced many variations on the simple "open circuit" plant, involving the use of heat exchangers, reheating and intercooling, water and steam injection, cogen

energy saving ratio (FESR), 170-177,

modification, 133-135, 147-152

per annum costs, 189

price, 191

saving, 170-173

179-180

Full oxidation, 134-135, 158-160

Gas supplied for combustion, 150

Gas turbine jet propulsion, xiii

Gas turbine, xiii

Gaseous fuel, 23

Gasifier, 114

GEM9001H plant, 128

General electric LM 2500 [CBT] plant, 83

General Electric company, 114

Gibbs function, 22

Graphical method, 35-36, 123-125

Global warming, 13 1

Greenhouse gases, 13 1

Gross entropy generation, 64-65

see also carbon dioxide removal

HAT cycle, 100, 106

HAT see humidified air turbines

Heat balance in the HRSG, 1 I8

Heat

balance, 90, 118-1 19, 183

electrical demand ratio, 170-173, 176-177

engines see closed cyclesfcircuits

exchange (or recuperation), 10, 9 1-92,

exchanger, 11, 32,96

exchanger effectiveness, 37, 93

loads, 170- 174

loss in the exhaust stack, 172

loss, 1 IO- I 12

rate, 7

recovery steam generator (HRSG), 85

combined cycle gas turbines, 1 12,

combined heat and power plants, 180

steam injection turbine plants, 87-88

94-98, 133, 147-150

114-115, 118-121, 126-128

rejection, 8-9, 18

transfer, 5, 14-17, 183-185, 186

transfer coefficient, 185

to work ratio, 175, 176-177, 179, 180

SUPPIY, 8-9, 37

Heating device (or boiler) efficiency, 5, 1 1 1, I 17

Heating value, 143, 150, 152 Heavy duty CCGT plant, 191 Heat Recovery Steam Generator HRSG, 1 12,

114, I I6 Humidified air turbine, 100, I O I , 104

Hydrogen burning CBT, 133 Hydrogen burning CCGT, 133, 154 Hydrogen plants, 133, 153-154 ICAR (irreversible Carnot), 22 Ideal (Carnot) power plant, 7-8 Ideal combined cycle plants, 109- 1 I O

Ideal heat exchangers, 91 IFB plant, 103

IFB see inlet fog boosting IGCC cycles with COz removal, 160 IGCC see integrated coal gasification cycles Integrated coal gasification combined cycle

plant (IGCC), 114, I15 IJB scc irreversible Joule-Brayton Inlet fog boosting (IFB), 103 Integrated coal gasification cycles (IGCC), Intercooled cycle, 32, 96

Intercooling and reheating, 39, 93 Intercooled steam injection turbine plants Intercooling, IO- 1 1

Interest rates, 190-191

lnternal irreversibilities, 8-9, 16, 19, 24

Internal irreversibility, 16, 19, 24 Internal Stanton number, I86

Internal thermal efficiency, SO

Internally reversible cycles, cooling, 49-55 Irreversible Carnot (ICAR) cycles, 22 Irreversible Joule-Brayton (IJB) cycle, 9, 21 Irreversible processes

air standard cycles, 33-39, 5 1, 54-59 power generation, 8-9

steady flow, 14, 17-18

114-115, 136, 161-162, 164

(ISTIG), 97-98, 103, 105

Irreversibility, 14, 17 Irreversible Joule-Brayton (LIB) cycle, 9, 20 Irreversible simple cycle, 34

Isentropic efficiency, 33 Isentropic

efficiency, 33-34 expansion, 53-54 temperature ratio, 35-39, 43, 66-67, 92-93

IS0 firing temperature, 47

Isothermal compression, 93

ISTIG plant, 98, 103, 105

see intercooled steam injection turbine

plants

Joint heating of gas turbine and steam turbine

Joule-Brayton cycle, 1, 3, 20, 28

Joule-Brayton (JB) cycle

plants, 112

air standard, 28-29, 46

efficiency, 9, I O

exergy flux, 20-22

power generation 1-2, 3

Linearised analyses, 42

Liquefaction, 134

Liquid fuel, 23

Live steam pressure, 122

Liverpool University plant (CHP), 180- 181

Loss in efficiency, 58, 1 I O

Lost work, 16, 17-18, 20-21

Lower heating value thermal efficiency, 124

Mach numbers, 62

Mainstream gas mass flow, 71 -72

Maintenance costs, 19 1

Massflow,42,71, 117-118

Mass flow ratio, 118

Matched CHP plant with WHB, 171

Matched CHP plant with WHR, 171

Matched plants, 171

Matiant cycle, 134-135, 158-160

Maximum combined cycle efficiency, 126

Maximum efficiency, 35, 38 66, 82, 126

Maximum efficiency, 126

Maximum (reversible) work, 17

Maximum specific work, 35

Maximum work, 15, 22

Maximum work output 22, 24-25

Maximum temperature, 47

Mean temperatures 8-9, 21

Methane, 141-143, 145, 192

Mixing of cooling air with mainstream flow, 61

Modifications

fuels, 133-135, 148-153

oxidants, 134-135, 155-161

turbine cycles, 9- 1 1

Modified polytropic efficiency, 59

Multi-step cooling, 52-54, 59, 7.5, 78-81 Multiple PO combustion plant, 163 Natural gas reforming, 133-134 Natural gas-fired plants, 164

NDCW see non-dimensional compressor work

NDHT see non-dimensional heat transferred NDNW see non-dimensional net work NDTW see non-dimensional turbine work

Nitrogen, 133, 153 Non-carbon fuel plants, 133, 153-155 Non-dimensional heat supplied, 41 Non-dimensional net work output, 40 Nondimensional

compressor work (NDCW), 35, 124 heat transferred (NDHT), 3, 122 net work (NDNW), 35-37,40, I23 turbine work (NDTW), 35, 124 Notation, turbine cooling, 184 Novel gas turbine cycles, 131 - 164

Nozzle guide vane rows, 60,63, 65,73-75, 78 Open circuit gas turbine plant, 2, 6, 13, 24, 39, Open circuit gas turbindclosed steam cycle, 1 13

Open cooled blade row, 6 1 , 6 2 Open cooling, 59-65, 186 Operating conditiondranges, 180- 18 1

Operational costs, 19 1 - 192 Operation and maintenance, 192 Optimum pressure ratios, 44-45, 123- 126 Overall cooling effectiveness, 185 Overall efficiency and specific work, 66, 78, 8 I Overall efficiency of CCGT plant, 12 I , 124 Overall efficiency

43

closed circuit power plants, 6 cogeneration plants, 167- 169 combined cycles, I 12, 1 18 128 129, 130 electricity pricing, 189- 190

fired combined cycles, 1 16 open circuit plants, 43-46 open circuit power plants, 6-7 recuperation, 92, 149- 151 steam injection turbine plants, 85, 86 steam-thermo-chemical recuperation, 33,

141, 143, 147 three step cooling, 79-81 water injection evaporative turbines, 94-98

wet gas turbine plants, 85, 87- 107

see also arbitrary

Oxidant modification, 135, 163

Oxygen blown integrated coal gasification

cycles, 161, 162

Parallel expansions, 5 1

Parametric calculations, 1 18- 12 1

Parametric studies, 97, 105, 107

Partial oxidation (PO), 134-135, 143, 155- 157

Partial oxidation cycles, 155

Partial oxidation reaction, 143

Performance criteria, 33, 168

Performance of unmatched CHP plants, 175

Physical absorption process, 136, I38

Physical absorption, 137, 139- 140

Pinch point temperature difference, 88, 118

Plant with a WHB, 174

Plant with supplementary firing, 11 6

Plants with combustion modification, 158

PO open CBT cycle, 135

PO plant with C 0 2 removal, 157

PO, 141, 143, 154, 155

Plant efficiency

calculations, 71 -83

electricity pricing, 189, 19 1 - 194

exergy, 82-83

turbine cooling, 68

PO see partial oxidation

Polytropic efficiency, 34, 59, 64

Polytropic expansion, 53, 59

Power

generation thermodynamics, I - 1 1

loads, 173- 174

plant performance criteria, 4

station applications, 13 1

Practical gas turbine cogeneration plants, 177

Pre-heating loops, 122- 123

Pressure

change, 62

dual systems, 123

live steam, 122- 123

losses, 33, 39, 75, 78

ratios

optimum, 44-45, 123- 126

turbine cooling, 66-68

water injection evaporative gas turbines,

96-98

stagnation, 60,61-65, 183 steam raising, 119-120, 121 two step cooling, 5 1-52 Process steam temperatures, 177, 178 Product of thermal efficiency and boiler

efficiency, 6, 1 1 I Range of EUF and FESR, 177, 179 Range of operation, 174

Rankine type cycles, 133, 154- 155 Ratio of entropy change, 9

Rational efficiency, 6, 22, 24-26, 42,

51, 60 Rayleigh process, 62 Real gas effects, 39,43, 45, 46,48, 65, Recirculating exhaust gases, 140- 141 Recuperated water injection (RWI) plant, Recuperation (heat exchange), 10- 1 1,90-92, Recuperative CBTX plant, 147

Recuperative cycle, 29, 30, 34, 37, 38, 92 Recuperative STIG plant, 90

Recuperative STIG type cycles, 148 Recycled flue gases, 144

Reference systems, 170- 173 Reforming reactions, 143, 148, 157, 158-159 Regenerative feed heating, 1 16, 122, 128 Reheat and intercooling, IO, I 1

Reheating in the upper gas turbine, 126 Reheating, 31, 39, 44, 45, 46, 126-128 Rejection, heat 8-9, 18

REVAP cycle, wet gas turbine plants, 100-101,

104,108 Reversed Camot engine, 18 Reversibility and availability, 13-26 Reversible closed recuperative cycle, 30 Reversible processes

air standard cycles, 28-33, 46,49 ambient temperature, 14- 15 availability, 13-26

heat transfer, 15-17 Reynolds number, 183, 186 Rolls-Royce, plc, xiii-xv, 83-84 Rotor inlet temperatures, 47-54, 56-57, 60, Running costs, 13 1

71,82

100-101, 104, 106-107

133, 147- 150

65-68

Ruston TB gaq turbine, 177, 180

RWI cycle, 100, 101, 103, 105, 106

RWI see recuperated water injection

Safety factor (cooling), 186

Scrubbing process, 147- 148

Semi-closure cycles, 134, 140- 141, 146- 148,

Semi-closed CBT or CCGT, 134

Semi-closed CCGT plant with C02 removal,

163, 164

Semi-closed CICBTBTX cycle, 135

Semi-closure, 139, 140, 158

Sequestration, 132, 134, 145-148

Shift reactor, 161 -162

Simple CHT cycle, 34

Simple EGT, 93, 96, 107

Simple PO plant, 155

Single pressure system, 122- 123

Simple single pressure system with feed heating,

Simple single pressure system without feed

Single pressure steam cycle with LP evaporator

Single pressure steam raising, 121

Single-step turbine cooling, 49-5 1, 55-57,

Specific enthalpy, 24

Specific entropy, 24

Specific heat, 35,41-42, 43, 88

Specific work

closed air standard cycles, 35

combined cycles, 123-124

open circuit plants, 45-46

steam-thermo-chemical recuperation, 150,

wet gas turbine plants, 104-107

157, 159-162

122

heating, 118

in a pre-heating loop, 123

73-75,76-78

151

Stack temperature, 1 19

Stagnation pressurdtemperature, 60,61-65,183

Stanton numbers, 183, 184-185, 186

Stationary entry nozzle guide vane row, 60-65

Steady-flow, I , 13

availability function, 14, 15, 23, 24

energy equation, 13, 85, 87, 91, 172

air ratios, 87-89, 150

enthalpy, 119

Steam

injection turbine plants (STIG), 85-86 intercooled, 97-98, 103, 105 recuperation, 91 -94, 133, 149- 150 thermodynamics, 103

reforming reactions, 143, 144, 148 thermo-chemical recuperation, 133, 143, turbines, 128

149, 150 Steam cooling of the gas turbine, 128 Steam injection and water injection plants, STIG and EGT, 85,97, 103

STIG cycle, 96, 97, 99, 103, 107 Stoichiometric limit, 47

STIG see steam injection turbine plants Sulphuric acid dewpoint, 122

Supplementary combustion, 172 Supplementary firing, 116, 173 Supplementary fired CHP plant, 172 Supplementary ‘heat supplied’, 120 Surface intercoolers, 105

Syngas, 114-115, 136, 143-144, 161-162

86

Taxes, 131, 162-164, 191, 192-194 Tax rates, 190

TBC (Thermal barrier coating), 185 TCR see thermo-chemical recuperation Temperature

TCR, 133, 141-143, 147-152, 157

adiabatic wall, 185 ambient, 13-14, 24 changes, 39,42-43 combustion, 47-49,55-57,68,73-84 dewpoint, 114, 119, 122

difference ratio, 71-72, 185, 187 economiser water entry, 119 exit turbine, 59

isentropic ratio, 35-39, 43, 66-67,

IS0 firing, 47

mean, 8, 21 pinch point, 1 18 power generation, 8-9 process steam, 177, 178 rotor inlet, 47-54, 56-57, 65-68 stack, 118

stagnation, 60, 61 -65, I83 turbine entry, 50, 58 92-93

Temperature-entropy diagrams

air standard cycles, 28, 33

combined cycle efficiency, 117

evaporative gas turbines, 91, 92

fired combined cycles, 1 16

ideal (Carnot) power plants, 7

intercooling, 32-33

Joule-Brayton cycles, I , 3, 28

multi-step cooling, 52

single-step cooling, 49-50, 55

thermal efficiency, 6- 1 I

two-step cooling, 5 1 , 58

water injection evaporative gas turbines,

94 - 96

Temperature - entropy diagrams, xi v

Texaco gasifier, 114

Thermal barrier coating (TBC), 185

Thermal efficiency

air standard cycles, 30-31, 35-37

artificial, 168

closed circuit power plants, 3-6

combined heat and power plants, 1 10- 1 I I ,

cooling flow rates, 47-68

evaporative gas turbines, 85

fired combined cycles, 117- 126

ideal (Camot) power plants, 7

ideal combined cyclic plants, 109- I I O

internal, 50

irreversible Joule-Brayton cycle, 20

modifying turbine cycles, 9- 1 1

open circuit power plants, 6

recuperative evaporative gas turbines,

steam injection turbine plants, 89

three step cooling, 79, 81

turbine cooling, 47-68

I68

92-93

Thermal energy, 18, 24

Thermal or cycle efficiency, 5, 7

Thermal ratio, 33

Thermo-chemical recuperation (TCR), 133, 134,

Thermodynamics

142-144, 148-153

open cooling, 59-65

power generation, 1 - 1 1

wet gas turbine plants, 103- 105

Three step cooling, 78-79, 80-81

Throttling, 52, 58

TOPHAT cvcle 101-102 104 107 Wet gas turbine plants, 85- 107

Total pressure loss, 63-65 Turbine

cooling, 47-69, 184, 186- 187 entry temperature, 47, 50, 56, 58, 119 exit condition, 54-55

mass flow, 42 pressure, 157- I58 work, 88, 94, 96 Turbo jet engines, xiii Two pressure systems, 121, 123, 129 Two-step cooling, 5 I -52, 58

Ultimate reversible gas turbine cycle, 33 Uncooled and cooled efficiencies, 57 Unfired plant, 1 12- 1 14, 167, 170, Unit costs, 189

Unit price of electricity, 189, 19 1 - 192 Unitised production costs, I89 Unmatched gas turbines, 173- 174, 175 Unused heat, 1 IO, 176- 177

Upper gas turbine cycles, 126-128 Useful heavwork, 177, 178

174-177

Value-weighted energy utilisation factor, 169 Van Liere cycle, 92, 101-102, 107

Van’t Hoff box, 142, 143

Waste heat boilers (WHB), 167-177, 180 Waste heat recuperators (WHR), 167-77, Water

180- 181 entry temperature, 1 14, 1 19, 122 gas shift reactions, 142-144 injection, 85-107

evaporative gas turbines, 94-98 Water injection into aftercooler, 95 Water injection into aftercooller and cold side of

heat exchanger, 95 Water injection into cold side of heat exchanger,

95 Westinghouse, 83 - 84 WestinghouseRolls-Royce WR2 I recuperated

[CICBTX], plant, 83 Wet and dry cycles compared, 104, 105 Wet efficiencies, 94

WHB see waste heat boilers

Whittle laboratory, xv

WHR see waste heat recuperators

Work

irreversible flow, 15, 17

lost, 16, 17-18, 20-21

open circuit plants, 39-42 output, 22, 24-26 potential, 18, 19, 24 reversible flow, 14, 16 turbine, 88, 94, 96

see also specific work

gas turbine efficiency has produced many variations on the simple "open circuit" plant, involving the use of heat exchangers, reheating and intercooling, water and steam injection, cogeneration and combined cycle plants These are described fully in the text

A review of recent proposals for a number of novel gas turbine cycles is also included In the past few years work has been directed towards developing gas turbines which produce less carbon dioxide, or plants from which the C02 can be disposed of; the implications of a carbon tax on electricity pricing are considered

In presenting this wide survey of gas turbine cycles for power generation the author calls on both his academic experience (at Cambridge and Liverpool Universities, the Gas Turbine Laboratory at MI1 and Penn State University) and his industrial work (primarily with Rolls Royce, plc) The book will be essential reading for final year and masters students in mechanical engineering, and for practising engineers

About the author

Sir John Horlock is an authority on turbomachinery and power plants and his books on axial compressors, axial turbines, actuator disk theory, combined heat and power and combined power plants are widely used and cited

He founded the Whittle Laboratory at Cambridge in 1973 and acted as its first Director He was then Vice-Chancellor firstly of Salford University and subsequently of the Open University

Sir John has been an advisor to Government and industry for forty years and has been

a non-executive director of several UK companies He was recently Treasurer and Vice-president of the Royal Society and was knighted for services to science, engineering and education in 1996