Rayong Electricity Generating Co.,Ltd.€¦ · I) ST-20 start-up too slow by HRSG-21 after schedule...

Rayong Electricity Generating Co.,Ltd.(REGCO)

18 February 2005

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REGCO CASESREGCO CASES’’ APPLICATIONAPPLICATIONFOR PROCESSFOR PROCESS--ITIT

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Requirements for ProcessRequirements for Process--ITIT

• Provide Database for Plant Historical Data• Provide Analytic Tool for Diagnostic• Monitor&Improve Plant Performance• Summarize all necessary Data for better

tracking• Provide Data Source for Engineer &

Supervisor as required

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Users for ProcessUsers for Process--ITIT

• Operator (all levels) - for basic functions• Operator - for Data Logging via PDA• Supervisor & Engineer for Analytic Functions(Historical and Special Trends)

• Efficiency for all functions• Maintenance • Executive & Management Levels

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REGCO Simplify DiagramREGCO Simplify Diagram

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CasesCases’’ ApplicationApplication

I) ST-20 start-up too slow by HRSG-21 after schedule outage.

II) Sometimes, ST-40 start-up faster than ST-10, ST-20, and ST-30 .

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CaseCase--II:: Steam TurbineSteam Turbine--2020


“After schedule outage, board operators feel that ST-20 start-up too slow by HRSG-21,when compared with start-up by HRSG-22 or other units”

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Possible Causes of problem• GT-21 compressor fouling ----> OK• HRSG-21 Coil problems --------> more data• Bypass Damper leakage --------> OK• No Problem (only feel) ----------> OK

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ST.20 start up curve at 2Jun03

.50.

100.150.200.250.300.350.400.450.500.550.600.650.700.750.800.850.900.950.

1,000.1,050.1,100.

1 11 21 31 41 51 61 71 81 91 101 111 121 131 141 151 161 171 181 191 201 211 221 231 241 251

Time (Min)

Valu

e

LP. STEAM TURB INLET PRESS( Actual หารดวย 50)

MAIN STEAM TURB INLET PRESS( Actual หารดวย 10)

LP. STEAM TURB INLET TEMP.

Main STEAM TURB INLET TEMP.

Tunbine speed( Actual คูณดวย 5)

Steam chest Temp.

Condenser press.

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HRSG.21 start up curve at 2Jun03

.5.

10.15.20.25.30.35.40.45.50.55.60.65.70.75.80.85.90.95.

100.105.110.115.120.125.130.135.140.145.150.

1 13 25 37 49 61 73 85 97 109

121

133

145

157

169

181

193

205

217

229

241

253

Time (Min)

Valu

e

Load GT21

LP.HRSG.21 Outlet Press Actual หาร

ดวย 5)HP.HRSG.21 Outlet Press

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HRSG. 22 start up curve at 2Jun03

.5.

10.15.20.25.30.35.40.45.50.55.60.65.70.75.80.85.90.95.

100.105.110.115.120.125.130.135.140.145.150.

1 13 25 37 49 61 73 85 97 109

121

133

145

157

169

181

193

205

217

229

241

253

Time (Min)

Valu

e

Load GT22

LP.HRSG.22 Outlet Press Actual หารดวย

5)HP.HRSG.22 Outlet Press

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CaseCase--II:: Steam TurbineSteam Turbine--2020HRSG.21& 22 start up curve at 2Jun03

.5.

10.15.20.25.30.35.40.45.50.55.60.65.70.75.80.85.90.95.

100.105.110.115.120.125.130.135.140.145.150.

1 13 25 37 49 61 73 85 97 109

121

133

145

157

169

181

193

205

217

229

241

253

Time (Min)

Valu

e

Load GT21

LP.HRSG.21 Outlet Press Actual หารดวย 5)

HP.HRSG.21 Outlet Press

Load GT22



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CaseCase--II:: Steam TurbineSteam Turbine--2020HRSG.21& 22 start up curve at 2Jun03

.5.

10.15.20.25.30.35.40.45.50.55.60.65.70.75.80.85.90.95.

100.105.110.115.120.125.130.135.140.145.150.

1 13 25 37 49 61 73 85 97 109

121

133

145

157

169

181

193

205

217

229

241

253

Time (Min)

Valu

e

Load GT21



Load GT22



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• HP Pressure for HRSG-21 increases faster than HRSG-22, but LP Pressure for HRSG-21increases slower than HRSG-22 at same load.

• Possible cause: HP water flow for HRSG-21 is higher than normal and causes heat absorption from exhaust gas instead of LP water flow.

• Different water flow from design But How?

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CaseCase--II:: Steam TurbineSteam Turbine--2020Possible Cause for Flow changes• LP Eco. Coil problems• LP Circulation Pump problems• HP Economizer Recirculation

valve is not working properly

“ After testing of HP EconomizerRecirculation valve, this valve is not operated as designed (full open during start-up) and cause changing of HP and LP flow. ”

“The compress air supply for this ACV is closed manually”

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CaseCase--IIII:: Steam TurbineSteam Turbine--4040

II) ST-40 start-up faster than ST-10, ST-20,and ST-30.

“For many times, Steam Turbine 40 start-up faster than other units (10,20, and 30).However, ST-40 always start-up as normal as other units. ”

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• Steam Turbines are controlled by EHC for start-up, shutdown, loading, and protective devices.

• REGCO’s steam turbines are designed for 3start-up modes; Cold, Warm, and Hot.

• For Cold Start-up Mode (casing temp. below 330oC), Steam Turbine is started and loaded with 2 load-rate, 0.333%/min when load is less than 35%, and 2.60%/min when load is higher than 35%)

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Steam Turbine Start-up Curve(Cold)

05

101520253035404550556065707580859095

100105110115120

1 13 25 37 49 61 73 85 97 109

121

133

145

157

Time (min)

%Lo

ad

Spec. % load Rate

Load Rate Change

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CaseCase--IIII:: Steam TurbineSteam Turbine--4040Trend Load ST.40(Cold) Y2003

05

101520253035404550556065707580859095

100105110115120

1 11 21 31 41 51 61 71 81 91 101

111

121

131

141

151

161

Time (min)

%Lo

ad

Spec. % load Rate % Actual Load(from PLC.)27Oct03-Not pass% Actual Load(from PLC.)17Nov03-Pass% Actual Load(from PLC.)23Jun03-Not pass% Actual Load(from PLC.)15Jul03-Pass% Actual Load(from PLC.)13Nov03-Not pass% Actual Load(from PLC.)8Sep03-Not pass% Actual Load(from PLC.)1Sep03-Not pass

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• Process-IT Data(23 Jun - 17 Nov 2003), were shown that ST-40 were started 7 times with designed load rate only 2 times, while 5 times of start-up were faster than design curve.

• The problems were caused by prior command from EHC to change load-rate from 0.333%/min to 2.6%/min before 35% load.

“After EHC checking, EHC was found that command signal was not stable and caused prior command. EHC Card was changed”

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EpilogueEpilogue

• At the starting point, Process-IT at REGCO are utilized as one of analytic tools for operation &maintenance persons to find out causes of problems.Moreover, the application could be extended due to skill and expertise of users to apply the large amount of information for their purposes.

“A large amount of data/information without utilization is equal to less data”

Thank you ...

REGCO

Rayong Electricity Generating Co.,Ltd.€¦ · I) ST-20 start-up too slow by HRSG-21 after schedule...

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Transcript of Rayong Electricity Generating Co.,Ltd.€¦ · I) ST-20 start-up too slow by HRSG-21 after schedule...