Advanced GE CCPP

8/3/2019 Advanced GE CCPP

1/20

GE Power Systems

Advanced Technology Combined Cycles

R.W. SmithP. PolukortC.E. MaslakC.M. JonesB.D. GardinerGE Power SystemsSchenectady, NY

GER-3936A

g


2/20


3/20

Contents

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1System Integration Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Steam Turbine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Shaft Train Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Steam-Cooling System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Integrated Control System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Plant Arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Integrated Gasification Combined Cycle (IGCC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Repowering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 List of Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 List of Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15


GE Power Systems s GER-3936As (10/00) i


4/20


GE Power Systems s GER-3936As (10/00) ii


5/20

Introduction The General Electric H technology combinedcycles represent the most advanced power gen-eration systems available today. These com-bined-cycle power generation systems canachieve 60% net thermal efficiency burningnatural gas. Their environmental impact perkilowatt-hour is the lowest of all fossil-fired gen-eration equipment. These highly efficient com-bined cycles integrate the advanced technology,closed-circuit steam-cooled 60 Hz MS7001Hand 50 Hz MS9001H gas turbines with reliablesteam cycles using state-of-the-art steam tur-bines and unfired, multi-pressure, reheat heat recovery steam generators (HRSGs).

System Integration Overview The STAG 107H and STAG 109H are offered ina single-shaft combined-cycle configuration.

Figure 1 is a conceptual presentation of an out-door power plant with this equipment. Thisconfiguration complements the cycle integra-tion between the steam-cooled gas turbine andthe steam bottoming cycle.

A diagram of the cycle ( Figure 2 ) shows anoverview of the three-pressure, reheat steamcycle and its integration with the gas turbinecooling system. Gas turbine cooling steam is

supplied from the intermediate pressure (IP)superheater and the high pressure (HP) steamturbine exhaust to the closed circuit system that cools the gas turbine stage 1 and 2 nozzles andbuckets. The cooling system operates in series

with the reheater, with gas turbine coolingsteam returned to the steam cycle cold reheat line.

Air extracted from the compressor discharge iscooled using water from the IP economizer.The cooled air is readmitted to the gas turbineand compressor to cool compressor wheels andselected turbine gas path components. Theenergy extracted from the compressor dis-charge air is returned to the steam cycle by gen-erating IP steam. A fuel gas heating system uti-lizes low grade energy from the HRSG toimprove combined-cycle thermal efficiency.

Water extracted from the discharge of theHRSG IP economizer is supplied to the fuel gas


GE Power Systems s GER-3936As (8/00) 1

Figure 1. Advanced technology combined-cycle unit


6/20

heater to pre-heat the fuel gas supplied to thecombustion system. The water leaving the fuelheater is returned to the cycle through the con-densate receiver to the condenser.

Performance

The rating point thermal and environmentalperformance is summarized in Table 1 for theadvanced technology single-shaft combined-cycle units burning natural gas fuel. Thegraphs in Figure 3 show the ambient tempera-

ture effect on performance for the STAG 107Has well as the part load performance. Thegraphs in Figure 4 show the ambient tempera-ture effect on performance for the STAG 109Has well as the part load performance.

The low NO x emissions are achieved by a Dry

Low NOx (DLN) combustion system. Theclosed circuit steam-cooling system also con-tributes to the low NO x emissions because aminimum of air bypasses the combustors forcooling the gas turbine hot gas path parts.



CoolingWater

Cooling Air CoolingSystem

ToStack

Air

Gas Turbine

Air Treatment

Condensate Pump

Fuel

IPHP

Heat RecoverySteam Generator Fuel

HeatingSystem

Gland SealCondenser

Generator

Attemp

Filter

LEGEND

Filter A

Filter B

Feedwater Pump

Condensate Filter

Fuel

SteamWater ExhaustAir

Steam Turbine

DeaeratingCondenser

LPLP

Figure 2. STAG 107H/109H cycle diagram

Table 1. Advanced technology combined cycle thermal and environmental performance

STAG 107H 400 5,687 6,000 60 < 9 1,790 1,888STAG 109H 480 5,687 6,000 60 < 25 1,790 1,888

Combined-CycleUnit

Net Power, MW

ThermalEfficiency (LHV), %

NOxEmissionsppmvd at 15% O 2

Thermal Dischargeto Cooling WaterBTU/kWh kJ/kWh

Net Heat Rate (LHV)BTU/kWh kJ/kWh

Notes:1. Ambient Air Conditions = 15C (59F), 1.0133 barA (14.7 psia), 60% RH2. Steam Turbine Exhaust Pressure = 0.04064 barA, (1.2 In HgA)3. Performance is net plant with allowances for equipment and plant auxiliaries with a once-through

cooling water system4. Three-Pressure, Reheat, Heat Recovery Feedwater Heating Steam Cycle


7/20



80%

90%

100%

110%

120%

130%

140%

150%

160%

170%

10.0% 20.0% 30.0% 40.0% 50.0% 60.0% 70.0% 80.0% 90.0% 100.0%

Power Output (Percent of Rated)

H e a

t R a

t e ( P e r c e n

t o

f R a

t e d )

Basis:15C (59F) ambient temperature,1.013 BarA (14.7 psia) ambient pressure,60% relative humidity,0.0508 BarA (1.5" HgA) ST exhaust pressure,2 x 851mm (33.5") LSB

80%

85%

90%

95%

100%

105%

110%

115%

120%

125%

0 10 20 30 40 50 60 70 80 90 100 110

Ambient Temperature (F)

O u

t p u

t ( P e r c e n

t o f R a

t e d )

98.0%

98.5%

99.0%

99.5%

100.0%

100.5%

101.0%

101.5%

102.0%

102.5%

H e a

t R a

t e ( P e r c e n t o

f R a

t e d )


Power

Heat Rate

Figure 3. S107H ambient temperature effect on performance and part load performance

80%

85%

90%

95%

100%

105%

110%

115%

120%

125%

0 10 20 30 40 50 60 70 80 90 100 110

Ambient Temperature (F)

O u

t p u

t ( P e r c e n

t o

f R a

t e d )

98.0%

98.5%

99.0%

99.5%

100.0%

100.5%

101.0%

101.5%

102.0%

102.5%

H e a

t R a

t e ( P e r c e n

t o

f R a

t e d )

Basis:15C (59F) a mbient temperature,1.013 BarA (14.7 psia) ambient pressure,60% relative humidity,0.0508 BarA (1.5" HgA) ST exhaust pressure,2 x 851mm (33.5") LSB

Power

Heat Rate

80%

90%

100%

110%

120%

130%

140%

150%

160%

170%

10.0% 20.0% 30.0% 40.0% 50.0% 60.0% 70.0% 80.0% 90.0% 100.0%

Power Output (Percent of Rated)

H e a

t R a

t e ( P e r c e n

t o

f R a

t e d )


Figure 4. S109H ambient temperature effect on performance and part load performance

Table 2. Advanced technology combined-cycle steam conditions

HP ThrottlePressure (psig/Barg) 2400/165Temperature (F/C) 1050/565

Hot Reheat Pressure (psig/Barg) 345/23.8

Temperature (F/C) 1050/565LP AdmissionPressure (psig/Barg) 31/2.2Temperature (F/C) 530/277

Exhaust PressurePressure (in. HgA/barA) 1.2/0.04064


8/20


9/20

ical integration as a single prime mover with asingle thrust bearing, thus minimizing the over-all machine length. Use of all solid rotor cou-plings provides maximum reliability and simpli-fies the control, overspeed protection, and aux-iliary systems.

The thrust bearing is located in the gas turbineinlet end bearing housing, which permits inde-pendent operation of the gas turbine for testingin the factory. This location is at the high pres-sure end of the steam turbine, which minimizesdifferential expansion and permits use of smallaxial clearances throughout the HP and IP sec-tions. The steam turbine contribution to theshaft thrust load is low and in the oppositedirection to that of the gas turbine, so that the

thrust bearing is lightly loaded under all oper-ating conditions.

A single lubricating oil system with AC- and DC-powered pumps provides oil to all shaft bear-ings and to the generator hydrogen seals.Similarly, a single high-pressure hydraulic fluidsystem is used for all control and protectivedevices.

Features: 1. Steam turbine installed between the

gas turbine and the field assembledhydrogen-cooled generator.

2. Solid coupling between gas turbineand steam turbine. Direct coupledsteam turbine shafts and direct coupled steam turbine to generator.

3. Single thrust bearing in the gasturbine compressor to fix shaft position in conjunction with tie rodinstallation between the steam turbinefront standard and the gas turbinecompressor inlet casing.

4. Steam turbine front standard keyed to

foundation.5. Common lube oil system with

hydrogen seal oil system. Commonfire-resistant hydraulic oil system.

6. Static start (LCI).

7. Turning gear mounted between steamturbine and generator



COL.

HP IP LP GEN.

TWO FLOW,DOWN EXHAUST

CT

BEARINGSOLID COUPLINGKEY FOR SHAFT POSITION

THRUST BEARING TIE RODS

CT

SINGLE FLOW,DOWN EXHAUST

COL.

GEN.LP IPHP

Figure 5. S107H and S109H single-shaft STAG equipment configuration

COL.

COL.

THRUST BEARINGSOLID COUPLING BEARING

TWO FLOW,DOWN EXHAUST

SINGLE-FLOW,DOWN EXHAUST

TIE RODS

KEY FOR SHAFT POSITION


10/20

8. Lift oil for gas turbine only.

9. Gas turbine, steam turbine, generator,and gas skid installed on a pedestalfoundation. All other modules (lubeoil, hydraulic, fuel oil/atomizing air,etc.) are installed at lower level. Shaft center line height (approximately 10.2M [33.5 feet] above grade)determined by gas turbine inlet duct location and/or steam turbinecondenser.

10. Single-flow or two-flow down exhaust steam turbine with sliding shellsupport on the fixed/keyed front standard.

11. Integrated unit control system (GT,ST, Gen, HRSG & Mechanical

Auxiliaries).

12. Integrated overspeed protection.

13. Down generator terminals.

14. Reheat, three-pressure steam cycle.

15. Integrated drawings - Shaft

Mechanical Outline, One-LineDiagram, Device Summary, PipingSchematics (Lube Oil, Hydraulic).

The selection of the single shaft as the pre-ferred configuration for the advanced technol-ogy combined cycles is based on the extensiveexperience since its introduction by GE in 1968.Table 4 presents the operating experience on 86GE single-shaft combined-cycle units with near-ly 18,000 MW of installed capacity.

Steam-Cooling System The gas turbine steam cooling system is inte-

grated with the steam bottoming cycle to reli-ably provide cooling steam at all operating con-ditions. The normal supply of cooling steam isfrom the outlet of the HRSG IP superheater,supported as necessary with HP steam turbineexhaust. The steam is delivered to the gas tur-bine stationary parts through casing connec-tions and to the rotor through a conventionalgland connection. The cooling steam isreturned to the steam cycle at the cold reheat



Wolverine ElectricCity of OttawaCity of ClarksdaleCity of HutchinsonSalt River Projects

Arizona Public Ser.Western FarmersTokyo ElectricChubu ElectricChugoku ElectricMinistry of Pet.Kyushu ElectricPower GenEPON

Tokyo ElectricChubu ElectricChina Light & Power Crocket CogenCogentrixTokyo ElectricBoffolora

AkzoGreat Yarmouth

Utility

Michigan, USAOttawa, KS, USAClarksdale, MS, USAHutchinson, MN, USASantan, AZ, USAPhoenix, AZ, USA

Anadarko, OK, USAFuttsu, JapanYokkiachi, JapanYanai, JapanLama Dien, ChinaShin-Oita, JapanConnahs Quay, UKNetherlands

Yokohama, JapanKawagowe, JapanBlack Point, Hong KongCalif, USAClark County, WAChiba, JapanItalyDelesto II, NetherlandsGreat Yarmouth, UK

Site

1111433

14561545

878114111

No.Units

21112111728393

165112125

50138350350

343235340248253360110360407

Unit

21112111

290250278

2310560750

50690

14001400

274216452720

248253

1440110360407

Plant

MS5001MS3002MS5001MS3002MS7001BMS7001CMS7001EMS9001EMS7001EMS7001EMS6001BMS7001EAMS9001FMS9001FA

MS9001FAMS7001FAMS9001FAMS7001FAMS7001FAMS9001FAMS6001FAMS9001FAMS9001FA

GasTurbine

19681969197219721974197619771986198819901990199219951995

199719981996199619971999199819992001

CommercialOperation

Rating (MW)

Total 86 17,967

Table 4. Single-shaft combined-cycle experience


11/20

line. The gas turbine cooling steam return andany HP steam turbine exhaust steam not usedfor gas turbine cooling are reheated in theHRSG and admitted to the IP steam turbine.

During unit acceleration to rated speed andoperation at low load, the gas turbine is cooledby air extracted from the compressor discharge.The air is filtered prior to supply to the coolingsystem. The cooling air from the gas turbinecooling circuit is discharged to the gas turbineexhaust. During air-cooled gas turbine opera-tion steam flow is established through the steamsupply system to warm the steam lines and sta-bilize the steam supply conditions prior toadmission of steam to the gas turbine coolingsystem. This steam is discharged via thereheater to the condenser through the IPbypass valve, which is modulated to maintainthe pressure of the cooling steam above the gasturbine compressor discharge pressure to pre-clude gas leakage into the steam cycle.

Appropriate shutoff valves isolate the gas tur-bine cooling circuit from the steam cycle whileit is operating with air cooling. These cooling

steam shutoff valves are included in the trip cir-cuit such that the system is transferred to aircooling immediately upon an emergency shut-down to purge steam from the cooling system.

Initial cooling steam supply and line warmingsteam is supplied from the HRSG. Steam isextracted from the HP superheater after thefirst pass and mixed with steam from the HPsuperheater discharge to supply steam to thecooling steam system at the required tempera-

ture. The cooling steam temperature control will match gas turbine cooling steam supply tothe gas turbine compressor discharge tempera-ture during transfer from gas turbine air cool-ing to gas turbine steam cooling, which occursprior to steam turbine loading. In addition toproviding start-up cooling steam supply to thegas turbine cooling steam circuit, the HP steam

extraction after the first superheater pass isused to cool the LP steam turbine from ~70%speed until steam turbine loading is underway.

Figure 2 includes a diagram of the three-pres-sure, reheat HRSG. While the system can beconfigured with either forced or natural circu-lation evaporators, Figure 2 shows a system withnatural circulation evaporators. The HRSG is atypical three-pressure, reheat HRSG that is com-monly applied in combined cycles. It includesthe following features to accommodate thesteam cooling system:

s The reheater size is reduced since part

of the reheating is performed by thegas turbine cooling steam system.s The reheater is located in the gas path

downstream of the high temperaturesection of the HP superheater. Thereheater receives steam during alloperating modes except at very lowloads during startup, prior toavailability of IP steam.

s HP steam is extracted after the first

pass of the HP superheater during lowload operation to establish gas turbinesteam cooled operation before thesteam turbine is loaded and providecooling steam to the LP steam turbineabove ~70% speed.

s Control of the HP steam temperatureis accomplished by a steamattemperation system which bypasses asection of the HP superheater. This

system eliminates the potential fordissolved contaminants to enter thesteam as can occur with attemperation

with feedwater. Attemperation steamis extracted after it passes through onepass in the superheater to assure that it will be dry after the small pressuredrop across the steam control valve.




12/20

Supply of high purity steam to the gas turbinecooling system is an essential requirement of the system for efficient long-term plant opera-tion with high availability. Features included in

the system to accomplish this requirement are:s Reliable condenser leakage detection

system with redundant condensateconductivity sensors and automatedprotection logic.

s Full flow feedwater filtration.s All cooling steam is purified by

evaporation in a steam drum withcontinuous monitoring of drum water

purity.s HP steam temperature control by

steam attemperation.s Full flow steam filtration.s Application of non-corrosive materials

in piping, filters and equipment downstream of the cooling steam shut-off valves.

The steam filter is the final line of defense

against particulate contaminants in the cooling

steam supply to the gas turbine. This device willoperate at least 24,000 hours without mainte-nance when provided with steam meeting thesystem purity requirements. The upstream sys-

tem design features and associated protectivestrategies provide a means of assuring thedesign life of the steam filter.

Figure 6 presents the location of the steam and water sampling points within the S107H andS109H combined-cycle systems. All samplingprobes and instrumentation (including a sam-pling panel) are of high sensitivity and reliabledesign. Steam and water conductivity, pH, andsodium measurements are continuously sam-pled and monitored. Other measurements not required for plant protection are monitoredintermittently.

Integrated Control System The single-shaft combined-cycle unit is con-trolled by an integrated, computer control sys-tem that coordinates the gas turbine, steam tur-bine, generator, HRSG and unit auxiliaries to

start, stop and operate the unit to meet system



HPDrum IP Drum

LPDrum

LP SteamTurbineExhaust

CoolingWater

C.A.C. HX Fuel Htg. HX

CC

Si

Na

Dis.O 2Extraction Probes

Legend:SC - Specific ConductivityCC - Cation ConductivityNa - Sodium Analyzer D.Ox - Dissolved OxygenSi - Silica Analyzer pH

1CC

Steam/Water Sampling and Monitor Panel

2SC

pH

Si

1SC

pH

1SC

pH

LP Steam toSteam Turbine

IP Steamto GasTurbine

HP Steam toSteam Turbine,

Gas Turbine

CC

Si

CC

Si

1SC

pH

All samples are taken oncontinuous basisNote: All HRSG sampling requirescooling and temperaturecompensation, minimize time for sampling process

DP

SC

8 extraction probes

Condenser (Divided

Waterbox)

Hotwell

Na

Filter A

Filter B

2SC

Figure 6. Steam and water sampling schematic


13/20

power requirements with input from a controlroom operator or from a remote dispatch area.The architecture for the single-shaft integratedcontrol system (ICS) for a single unit is shown

on Figure 7 . Figure 8 shows the architecture fora multiple-unit plant.

A redundant data highway connects all controlcomponents with the central control room con-soles. Historical archival and retrieval of plant data assists performance optimization andequipment maintenance. Time synchronizationof all control components provides time coher-ent, time tagged data for process monitoring,historical archival, sequence of events logging,

real time trending and comprehensive alarmmanagement. High speed communicationinterfaces link the plant control to external dis-patch and control systems.

The control and protection strategies are inte-grated between all components of the system.High levels of fault tolerance maximize unit starting and running reliability for both base

load and daily start service. The high degree of control integration maximizes automation of startup, shutdown and normal operations,

which reduces plant operating costs.

Easy to configure color graphic displays providea common look and feel to both the unit and

plant level control. Windowed displays enablethe operator to constantly monitor the desiredprocess and simultaneously view detailed pop-up windows to trend equipment operating dataor diagnose process problems. An engineering

workstation enables the operator to configureand tune control loops, perform detailed con-trol and process diagnostics, maintain software,

manage the system configuration and generateoperation reports.

The ICS is designed with dedicated I/O(inputs/outputs) to control the engineeredequipment packages. In addition, it has the flex-ibility and expandability needed to addressadditional I/O requirements to satisfy individ-ual owner requirements. This includes both



Control Room

Redundant Unit Data Highway

HRSG/MA

Generator

Steam Turbine

Gas Turbine BOPEquipment

Generator Excitation

&Protection

StaticStarter

SteamTurbine

&BypassControl

GasTurbine &

CoolingSteamControl

HRSG &Steam CycleMechanical Auxiliaries

Unit AuxiliaryControl

HMI/Server

HMI/Server

AlarmPrinter

Color DisplayPrinter

LogPrinter

Operator Station Historian

Remote Dispatch

Fault Tolerant Plant Data Highway

Operator Station

EngineeringWorkstation

Figure 7. Single-shaft combined-cycle unit integrated control architecture

All New Microprocessor Design

Triple Modular Redundant

Remotable I/O

Capability for I/O Expansion

Redundant Control and Plant Data

Highways

Peer-to-Peer Communications

Time Synchronized Unit Controls

Time Coherent System Data


14/20

redundant and non-redundant I/O which isintegrated with serial remote I/O (e.g.GENIUS, Fieldbus) and connections to pro-grammable logic control systems. All I/O pointsare available to the controls database for theintegrated system.

The speed and load control for the unit oper-ates through control of the gas turbine fuel

valves. The steam turbine control valves areclosely coordinated, being closed at startupuntil steam at sufficient pressure and tempera-ture for admission is available from the HRSG.They are then ramped open and held in fixedposition as load is changed with sliding pres-sure. The steam turbine control valves do not participate in normal frequency control. The

HP and LP control valves begin to close whenspeed rises to 103% of rated speed and are fully closed at 105%.

The intercept valves operate in a pressure con-trol mode at low load to maintain proper steampressure in the gas turbine steam cooling sys-tem. With increasing speed the intercept valveslag the control valves by 2% speed, beginning to

close at 105% rated speed and reaching thefully closed position at 107% of rated speed.This normal governing characteristic is overrid-den by a power/load unbalance-sensing featureupon the sudden loss of significant electricalload. Pressure in a steam turbine stage, repre-

sentative of steam turbine output, is summed with a gas turbine fuel flow signal and continu-ously compared with the generator electricaloutput. When a significant imbalance of powergenerated over electrical output is detected thecontrol and intercept valves are closed as rapid-ly as possible, limiting the speed rise to less thanthe 110% setting of the emergency overspeedtrip. Ultimate protection against excessive over-speed is provided by the emergency governor

that trips the unit by simultaneously closing allgas turbine fuel and steam turbine control andstop valves.

The sequencing system automatically starts theunit from a ready-to-start condition and loads it to gas turbine base load or a preset load. Table 5 shows starting time from initiation to full load.

Figure 9 presents an overview of the starting and



Remote Dispatch

Gateway

Control Room

BOPEquipment


&Protection

StaticStarter

Steam Turbine&

Bypass Control

Gas Turbine& Cooling

SteamControl


BalanceOf

Plant

Operator Station

Operator Station

AlarmPrinter

Color DisplayPrinter

Bridge

LogPrinter

Operator Station

LongTerm

Historian

Fault Tolerant Plant Data Highway

AdditionalOperator Station

AdditionalOperator Station

AdditionalPrinters

BOPEquipment

HRSG/MA

Generator

Steam Turbine

Gas Turbine


&Protection

StaticStarter

Steam Turbine&

Bypass Control


SteamControl


BalanceOf

Plant

Operator Station

Operator Station

AlarmPrinter

Redundant Unit Data Highway #3

HRSG/MA

Generator

Steam Turbine

Gas Turbine

BOPEquipment


&Protection

StaticStarter

Steam Turbine&

Bypass Control


SteamControl


BalanceOf

Plant

Operator Station

Operator Station

AlarmPrinter

HRSG/MA

Generator

Steam Turbine

Gas Turbine



Figure 8. Multiple-unit station control architecture


15/20

loading sequence for a hot start. Figure 10 is asimilar presentation of the cold start sequenceof a single unit. Note the speed hold shown fordeveloping steam for steam turbine cooling,

which is not required in multi-unit installations where running units can be used to support steam turbine cooling needs of the startingunit.

Start Standby Time toDesignation Period (hrs) Full Load (min)

Hot 0-12 60 Warm 12-48 120

Cold >48 180

Plant Arrangement The high power density of the advanced tech-nology combined-cycle systems enables a com-pact plant arrangement. Typical plan and eleva-tion arrangements are shown in Figure 11 withoverall dimensions for outdoor STAG 107H andSTAG 109H plants. In this arrangement, the

steam turbine has a single-casing and single-flow exhaust as would be applied at a site withsteam turbine condenser cooling that accom-modates the higher range of exhaust pressures.

Plants using steam turbines with double-flowexhausts are approximately 10 feet (3m) longer.The plan area for the 60 Hz advanced technol-ogy combined cycle is approximately 10% larg-er than that for current technology combinedcycles, while the power is increased approxi-mately 60% so that the plot space per unit of installed capacity is reduced approximately 45%.

Plant related considerations that influence theselection of the single-shaft configuration forthe advanced technology combined cycle aretabulated in Table 6 . The gas turbine cannot operate independently of the steam cycle sothere is no operating flexibility advantage forthe multi-shaft system. The single-shaft system islower in installation cost because of the singlegenerator, main electrical connections, trans-former and switchgear as compared to two forthe multi-shaft system.



Table 5. Starting time from initiation to full load

0

10

20

30

40

50

60

70

80

90

100

110

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75

Time from Synchronization (minutes)

. . % S

p e e d , % N

e t P l a n

t O u

t p u

t . .

Bring steamturbine online.

Transfer from air tosteam.

Normal loading

SPEED

OUTPUT

Figure 9. Typical S107H/S109H hot start loading profile

Time from Roll Off (minutes)


16/20


17/20

Integrated Gasification Combined Cycle (IGCC) The IGCC is broadly recognized as the coal-

fired generation plant with the best environ-mental performance. Integration with theadvanced technology combined cycle also willenable it to be the most economical power gen-eration system firing coal, petroleum coke,heavy residual oil and other solid or low gradeliquid fuels. Figure 12 shows a diagram of a typ-ical unitized advanced technology IGCC system

with an oxygen blown gasifier and integrationof the air separation unit with the gas turbine.

The range of ratings for the advanced technol-ogy IGCC plants are shown in Table 7 :

IGCC Frequency Capacity Thermal Net UNIT Hz Range LHV

(MW) Eff. Range (%)STAG 107H 60 400-425 45-49STAG 109H 50 500-530 45-49

The capacities and efficiencies are shown asranges because they vary with plant economicconsiderations and the type of gasifier, gascleanup system, air and steam cycle integration

and the coal or other solid fuel analysis andmoisture content.

Key features of an advanced technology IGCCplant that enable economical power generationare:

s Low installed cost resulting from thecapacity of the unit which enables it tobe matched with a single large gasifier.

s High efficiency which reduces fuel

consumption and further reducesplant cost by reducing the capacity of the gasification and cleanup systemper unit of installed generationcapacity.

Repowering The advanced technology combined-cycle sys-tem is readily adaptable to the repowering of existing steam turbine generator units. The



Dimension STAG STAG(M/Ft) 107H 109H

A 129/424 136/445B 46.3/152 48.6/159C 94.9/309 98.9/325

Figure 11. Single-shaft unit plan and elevation

A

B

C

Table 7. Ratings for advanced technology IGCCplants


18/20

integration of the steam cycle with the gas tur-bine cooling system requires appropriate con-sideration, but several methods for matchingthe cooling requirements to the existing steam

cycle are available and include the following:s The cooling steam temperature and

pressure for the MS7001H andMS9001H gas turbines are in the samerange as those of the cold reheat steam in many conventional steamunits with 2400 psig (165 bar) throttlepressure.

s Apply cooling water and existingsupport facilities and replace the

existing steam turbine with a modern,high efficiency steam turbine that isspecifically matched to the combined-cycle requirements. This option isattractive when the use of existing

water permits can minimize sitepermitting work.

A wide range of steam turbine ratings can bematched to the MS7001H and MS9001H gas

turbines by retaining existing feedwater heatersas may be necessary to meet exhaust flow limi-tations.

Conclusion The GE advanced technology combined cyclespromise improved economics of electric powergeneration with outstanding environmentalperformance in natural gas and coal-fired appli-cations. These characteristics are enhanced by

the evolutionary development from a technolo-gy base with extensive experience, whichassures low maintenance and reliable, conven-ient operation.



GasTurbine

SteamTurbine

Generator ElectricPower

Air SeparationUnit Gasifier

GasCleanup

Heat RecoverySteam

Generator

C o

l d R e

h e a

t

L . P .

I.P.

M a i n

H o

t R e h e a

t

Coal

Air

Air

A i r

N i t r o g

e n

Air Exh. GasNitrogenCoalCoal GasSteam

Water Oxygen

GasCooler

Figure 12. Unitized advanced technology IGCC system


19/20

List of Figures Figure 1. Advanced technology combined-cycle unit

Figure 2. STAG 107H/109H cycle diagram

Figure 3. S107H ambient temperature effect on performance and part load performanceFigure 4. S109H ambient temperature effect on performance and part load performance

Figure 5. S107H and 109H single-shaft STAG equipment configuration

Figure 6. Steam and water sampling schematic

Figure 7. Single-shaft combined-cycle unit integrated control architecture

Figure 8. Multiple-unit station control architecture

Figure 9. Typical S107H/S109H hot start loading profile

Figure 10. Typical S107H/S109H cold start loading profile, single unit

Figure 11. Single-shaft unit plan and elevationFigure 12. Unitized advanced technology IGCC system

List of Tables Table 1. Advanced technology combined-cycle thermal and environmental performance

Table 2. Advanced technology combined-cycle steam conditions

Table 3. Last-stage buckets for advanced technology combined-cycle applications

Table 4. Single-shaft combined-cycle experience

Table 5. Starting time from initiation to full load

Table 6. Combined-cycle configuration comparison summary

Table 7. Ratings for advanced technology IGCC plants




20/20


GE P S 16

Advanced GE CCPP

Documents

Transcript of Advanced GE CCPP