CCPP Start-up Curves RERERENCE PROJECT : F Class GTG Combined Cycle, 2-2-1 Multi Shaft Configuration CCPP Start-up IP LP Steam System Start-up , HP Steam System Start-up Time . , HP Steam STG , HP Drum Steel Water Temperature Change Rate . Reheater Tube Ramping-up Time , HP Steam System , Reheat Type CCPP Start-up Curves HP Steam System . 1. Pre-warming of HRSG HP Drum Water 1) Pre-warming HP Drum Pre-warming System HP Drum . , HP Drum Water (Sub-cooled) Start-up ( 15 oC), HP Drum Water Temperature Change Rate Control , HP Drum Water Temperature 100 oC Pre-warming System . Pre-warming Drum Water Hammering , , HP Drum . Water Hammering Pre-warming Sparging Steam Injection Flow Rate . Pre-warming . REFERENCE PROJECT HP Drum Pre-warming 185 oc, Pre-warming Steam Line Temperature Control Valve(TCV) , HP Drum 185 oC TCV HP Drum 185 oC Injection Sparging Steam Flow Rate Hammering . (180 oC Open, 185 oC Close Open-Close Control, Sparging Flow TCV Opening .)

Sparging Steam Aux. Boiler Turn-down Ratio TCV , HP Drum 140 oC Sparging Steam Manual 185 oC , Injection Flow Rate Hammering . HP Drum Water , Pre-warming Pre-warming Water Hammering . HP Drum Pre-warming Gas Turbine HRSG Temp Match Gas Turbine Exhaust Gas Pre-warming , .

1) Gas Turbine Exhaust Gas Flow Temperature , HP Drum Allowable Temperature Change Rate . 100 oC , 100 oC 10 kg/cm2g Start-up Vent Valve Bypass Valve , HP Drum Allowable Temperature Change Rate .

2) NOx Gas Turbine ,

2 , .

HRSG HP Drum , HP Drum Allowable Temperature Change Rate . 140 kg/cm2g REFERENCE PROJECT , HP Drum Cold Start Allowable Temperature Change Rate 3.9 oC/min. , IP Drum(27 kg/cm2g) 10 oC/min. LP Drum(7 kg/cm2g) 27.8 oC/min.. 2) Pre-warming

Pre-warming 10 kg/cm2g 185 oC . , 10 kg/cm2g Start-up Vent Bypass Valve . , Sparging Steam Pre-warming . 10 kg/cm2g , 185 oC , Sparging Steam . , Sparging Steam , Pre-warming . 3) Pre-warming Time

- HP Evaporator Drum Water Steel CMC = Mw Cpw + Mstl x Cps wherein ; CMC : Combined mass multiplied by Cp of HP Evaporator/Drum Water & Steel Mw : Water mass Cpw : Water specific heat Mstl : Steel mass Cps : Steel specific heat ) Water mass = 54432 kg, Water Cp = 1 kcal/(kg-oC) Steel mass = 22680 kg, Steel Cp = 0.12 kcal/(kg-oC) CMC = 54432 x 1 + 22680 x 0.12 = 57154 kcal/oC

- Sparging Steam HP Drum Water HA = Ms x {Hs (Hwf Hwi) / 2} wherein : HA : Heat added by sparging steam Ms : Sparging steam mass flow rate (decided by supply system) Hs : Sparging steam enthalpy

Hwf : Final enthalpy of HP drum water Hwi : Initial enthalpy of HP drum water ) Ms = 4536 kg/hr (sparging steam system sizing flow rate), Hs = 694 kcal/kg, Hwf = 187.6 kcal/kg(saturation water enthalpy at 185 oC), Hwi = 15.1 kcal/kg(Sub-cooled water enthalpy at 15 oC) HA = 4536 x {694 (187.6 15.1) / 2} = 2756252 kcal/hr

- Temperature Rising Rate by Sparging TRR = HA / CMC ) TRR = 2756252 kcal/hr / 57154 kcal/oC = 48.2 oC/hr = 0.8 oC/min.

- Pre-warming Time PWt = (Twf Twi) / TRR wherein : Twf : Final water temperature of HP drum water Twi : Initial water temperature of HP drum water ) PWt = (185 oC 15 oC) / 0.8 oC/min. = 213 min.

) Hot Warm Start-up Start-up HP Drum Pre-warming Pre-warming . 2. GTG Start-up through HRSG Temp Matching Load Gas Turbine Start-up Start-up Vent Valves Bypass Valves , Drain Valves . Drain Valves Steam , GTG Start-up Steam Flow , GTG Exhaust Gas Purge HP Drum Water , Firing HP Drum .

, Purge HP Drum Water Firing , Purge Firing HP Drum , . Steam Flow Gas Turbine Generator Synchronization HP Drum 0.7 kg/cm2g , HP Drum 0.7 kg/cm2g Start-up Vent Valves Flow . Hot Start-up HP Drum Gas Turbine 0.7 kg/cm2g , Gas Turbine Generator Synchronization Start-up Vent Valves Flow . Gas Turbine Generator Synchronization Start-up Vent Valves , Gas Turbine Generator Synchronization Start-up and Synchronization , HP Drum . Gas Turbine Generator Synchronization Gas Turbine HRSG Temperature Matching . HRSG Temperature Matching HRSG Superheater Reheater Tubes Tubes , Gas Turbine Exhaust Gas Temperature Tubes Gas Turbine . Superheater Reheater Carbon Steel , HRSG Temperature Matching Carbon Steel Creep Temperature 427 oC . RERERECNE PROJECT HRSG Temperature Matching 400 oC . HRSG Temp Matching Tubes , HRSG Start-up Mode(Cold, Warm, Hot) . 1) Gas Turbine Start-up Gas Turbine Start-up DCS APS(Automatic Plant Start-up & Shut-down) Start , Purge Cycle Firing, IGV Open to Minimum Angle Grid FSNL(Final Speed No Load) , Auto Synchronization ON Grid Synchronization Minimum Load . `

Gas Turbine Exhaust Gas Flow Temperature APS Gas Turbine , Gas Turbine Gas Turbine Start-up Curves . Purge Cycle Start HRSG Purge Cycle . Purge Cycle HRSG Gas Turbine Cycle, Gas Turbine Start-up Device(SFC, Motor ) Gas Turbine 23% Speed . NFPA Purge Volume HRSG Gas Volume 5 Volume , REFERENCE PROJECT Purge Time 11 . Purge Cycle HRSG HRSG , .

- HP Evaporator Drum Water Steel CMC : CMC : Combined mass multiplied by Cp of HP Evaporator/Drum Water & Steel (Pre-warming Time CMC ) CMC = 57154 kcal/oC

- Heat removed by Air HRA = Ma x Cpa x (Twf Ta) / 2 wherein : Ma : Gas turbine purge air mass flow(Gas Turbine Data ) Cpa : Specific heat of air Twf : HP drum water temperature before GT start Ta : Ambient air temperature ) Ma = 120512 kg/hr, Cpa = 0.24 kcal/(kg-oC) Twf = 185 oC, Ta = 15 oC

HRA = 120512 x 0.24 x (185 15) = 2463269 kcal/hr

- HP Drum Water Temperature Drop Rate during Purge Cycle TDR = HRA / CMC ) TDR = 2463269 / 57154 = 43.1 oC/hr = 0.72 oC/min.

Firing through Synchronization Purge Cycle Gas Turbine(GT) Speed 13% Firing . GT IGV Angle 43 28 , GT Speed (Acceleration) GT Exhaust Gas . GT Speed 66% Starting Device Disengage GT Exhaust Gas , GT Speed 90% GT IGV Angle 43 GT Exhaust Gas . FSNL Synchronization . GT Exhaust Flow Rate GT Speed IGV . Gas Turbine Speed & Output, Exhaust Flow & Temp, IGV Angle Gas Turbine GT Start-up Curve . HP Steam , HP Drum , . GT Exhaust , FSNL Synchronization HP Drum .

- FSNL Synchronization GT Exhaust Gas Enthalpy Gas Turbine GT Exhaust Gas FSNL Synchronization GT Exhaust Gas GT Exhaust Gas Enthalpy . (Flue Gas Enthalpy Software ) Tgf, Tgs : GT exhaust gas temp at FSNL and Synchronization respectively Hgf, Hgs : GT exhaust gas enthalpy at FSNL and Synchronization respectively

) GT Exhaust Gas Composition(volume %) : N2 = 74.6, Ar = 0.9, O2 = 12.7, CO2 = 3.8, H2O = 8 Tgf = 420 oC (GT Exhaust Gas Temp at FSNL) Tgs = 450 oC (GT Exhaust Gas Temp at Synchronization) Hgf = 104.6 kcal/kg at Tgf (15 oC ) Hgs = 112.7 kcal/kg at Tgs (15 oC )

- HP Evaporator Outlet Gas Enthalpy GT Start-up , Pinch Design Pinch . Firing Pinch Design Pinch HP Evaporator Outlet Gas Temperature Enthalpy . Tgevap = Twf + Dpinch Wherein, Tgevap : HP evaporator outlet gas temperature Twf : HP drum water temperature before GT start DPinch : HP evaporator design pinch value Hgevap = Gas enthalpy at Tgevap ) HP drum water temp FSNL Pre-warming , Pre-warming . , FSNL Synchronization Tgevap . ) Twf = 185 oC, DPinch = 8.9 oC Tgevap = 185 + 8.9 = 193.9 oC Hgevap = 44.7 kcal/kg (15 oC )

- Heat added to HP Evaporator Water by Gas (FSNL Synchronization ) HAEVAP = (Mgf + Mgs) / 2 x {(Hgf + Hgs) / 2 Hgevap}

wherein : HAEVAP : Heat added to HP evaporator water by gas Mgf, Mgs : GT exhaust gas flow at FSNL and Synchronization respectively Time_f, Time_s : Time at FSNL and Synchronization respectively Hgf, Hgs : GT exhaust gas enthalpy at FSNL and Synchronization respectively Hgevap = Gas enthalpy at Tgevap ) Mgf = 860 t/h, Mgs = 990 t/h, Hgf = 104.6 kcal/kg, Hgs = 112.7 kcal/kg Hgevap = 44.7 kcal/kg HAEVAP = (860 + 990) / 2 x {104.6 + 112.7} / 2 44.7} = 59.2e+6 kcal/hr

- Temperature Rising Rate TRR1 = HAEVAP / CMC / 60 * HAEFF wherein ; TRR1 : Temperature rising rate CMC : Combined mass multiplied by Cp of HP Evaporator/Drum Water & Steel (Pre-warming Time CMC ) HAEFF : Effectiveness of heat added ) CMC = 57154 kcal/oC, HAEFF = 0.15 TRR1 = 59.2e+6 / 57154 / 60 * 0.15 = 2.6 oC/min. ) GT Firing HRSG , GT HRSG Casing Structure . , GT HRSG HP Evaporator Water Steel , Effectiveness of Heat Added . Effectiveness 15% .

2) HRSG Temperature Matching HRSG Pre-warming GTG Synchronization HRSG HP Drum Water

0.7 kg/cm2g , GTG Synchronization HRSG HP Start-up Vent Valves HP Steam Flow . HRSG HP Drum Pre-warming , HP Start-up Vent Valves Opening , GTG Exhaust Gas , Steady-status HRSG Temperature Matching Steam Flow . , HP Start-up Vent Valves Opening HP Steam HRSG Temperature Matching Steam Flow , GTG HRSG Temperature Matching Bypass Valves HRSG HP Drum Floor Pressure , HP Steam HP Steam , HP Steam Flow HRSG Temperature Matching Steam Flow . , HRSG HP Steam Steady-status HP Steam Flow . HP Steam , HP Steam HP Drum Evaporator Water/Steel . , HRSG Temperature Matching Load HP Steam 10 kg/cm2g , Steady-state HP Steam Flow 72 ton/hr , 3.9 oC/min. HP Drum Water HP Steam Flow 50 ton/hr. 22 ton/hr HP Steam Flow HP Drum Evaporator Water/Steel . HP Drum Water , HP Steam Flow . HRSG HP Drum Water Pre-warming , Hot Start-up , GTG Synchronization 5 3.9 oC/min. HP Drum Water HRSG Temperature Matching HP Steam Flow , Drum HP Steam Flow . Cold Start-up , 10 kg/cm2g 3.9 oC/min. , HP Steam Flow .

- UA Calculation from Design Conditions

Q = U x A x LMTD HRSG . Q , U , A , LMTD Log Mean Temperature Difference. U , , Design Conditions UA , UA Design UA . UA = Q / LMTD wherein : UA : Heat transfer area(A) multiplied by overall heat transfer coefficient(U) LMTD : Log mean temperature difference ) Design Conditions HP superheater outlet steam : Ms = 185.5 t/h, Ps = 131.4 atg, Ts = 567 oC, Hs = 839.1 kcal/kg HP evaporator inlet feedwater : Mf = 185.5 t/h, Pf = 139 atg, Tf = 332 oC, Hf = 367.4 kcal/kg, Tsat at Pf = 335.1 oC GTG exhaust gas : Mgi = 1636 t/h, Tgi = 603 oC, Hgi = 155.1 kcal/kg HP evaporator exit gas : Mge = 1636 t/h, Tge = 344 oC, Hge = 84.3 kcal/kg Heat transferred by gas : Qgas = Mgi x (Hgi Hge) = 1636 x (155.1 84.3) = 115,884 Mcal/hr Heat received by HP steam : Qs = Ms x (Hs Hf) = 185.5 x (839.1 367.4) = 87,506 Mcal/hr HP steam heat ratio to gas : Rq = Qs / Qgas = 87,506 / 115,884 = 0.755 ) Gas HP Steam , Reheater .

. LMTD = {(Tgi Ts) (Tge Tf)} / ln{(Tgi Ts) / (Tge Tf)} = {(603 567) (344 332)} / ln{(603 567) / (344 332)} = 21.8 oC UA based on Qgas = Qgas / LMTD = 115,884 / 21.8 = 5,305 Mcal/(hr-oC) Design Pinch = Tge Tsat at Pf = 344 335.1 = 8.9 oC Design Approach = Tsat at Pf Tf = 335.1 332 = 3.1 oC

- Off-design Steady-state Performance based on Constant UA ) Pinch Approach Design . Pinch Approach Design , , . LMTD_Q = LMTD)_T wherein : LMTD_Q : LMTD calculated based on heat transfer LMTD_T : LMTD calculated based on HP steam temperature presumed )Off-design Conditions for HRSG Temperature Matching Load at 10 atg HP Drum Pressure GTG exhaust gas : Mgi = 1050 t/h, Tgi = 400 oC, Hgi = 99.2 kcal/kg HP drum pressure : Pdrum = 10 atg, Tsat at Pdrum = 183.2 oC HP evaporator exit gas : Mge = 1636 t/h, Tge = Tsat at Pdrum + Design Pinch = 183.2 + 8.9 = 192.1 oC, Hge = 44.7 kcal/kg Heat transferred by gas :

Qgas = Mgi x (Hgi Hge) = 1050 x (99.2 44.7) = 57,262 Mcal/hr LMTD_Q = Qgas / UA = 57,262 / 5,305 = 10.8 oC HP superheater outlet steam temperature presumed, Ts = 391 oC : HP evaporator inlet feedwater temperature, Tf = Tsat at Pdrum Design Approach = 183.2 3.1 = 180.1 oC LMTD_T = {(Tgi Ts) (Tge Tf)} / ln{(Tgi Ts) / (Tge Tf)} = {(400 391) (192.1 180.1)} / ln{(400 391) / (192.1 180.1)} = 10.4 oC Therefore, LMTD_Q = LMTD_T and HP superheater outlet steam temperature, Ts = 391 oC is OK. HP superheater outlet steam : Ps = 9 atg(estimated), Ts = 391 oC, Hs = 775.2 kcal/kg HP evaporator inlet feedwater : Pf(= Pdrum) = 10 atg, Tf = 180.1 oC, Hf = 182.4 kcal/kg Heat received by HP steam : Qs = Qgas x Rq = 57,262 x 0.755= 43,239 Mcal/hr HP steam generated, Ms = Qs / (Hs Hf) = 43,239 / (775.2 182.4) = 72.9 t/h

- Heat Reduction by Temperature Ramping Qred = CMC x TRR2 wherein ; Qred : Heat reduction by temperature ramping TRR2 : Temperature rising rate CMC : CMC : Combined mass multiplied by Cp of HP Evaporator/Drum Water & Steel (Pre-warming Time CMC )

) CMC = 57154 kcal/oC, TRR2 = 3.9 oC/min. Qred = 57,154 / 1000 x 3.9 x 60 = 13,373 Mcal/hr

- HP Steam Flow at Temperature Ramping Qs_ramp = Qs Qred Ms = Qs_ramp / (Hs Hf) wherein : Qs_ramp : HP steam flow at temperature ramping ) Qs_ramp = 43,239 - 13,373 = 29,866 Mcal/hr Ms = 29,866 / (775.2 182.4) = 50.4 t/h

3. HRSG Pressure Building-up to Floor Pressure GTG HRSG Temperature Matching , Allowable HP Drum Temperature Ramping Rate HP Steam Pressure Floor Pressure . Bypass Valves , HP Start-up Vent Valves , Condenser , Floor Pressure Bypass Valves Bypass Valve Desuperheater . , Floor Pressure STG Temperature Matching Start-up Time . Hot Start-up STG Temperature Matching HP Steam Bypass Valve Desuperheater , Bypass Valves , STG Temperature Matching . HRSG Temperature Matching HP( Reheat) Steam Carbon Steel Creep Temperature , Bypass Valves Carbon Steel, Bypass Valve Desuperheater Bypass Valves .( .)

, GTG HRSG Temperature Matching Bypass Valves Minimum Opening , HP Drum Temperature Ramping Rate Control Mode Bypass Valves HP Steam Pressure Control Floor Pressure , HP Start-up Vent Valves . , HP Steam Bypass Valve Desuperheater Minimum Volume Flow Bypass Valve Desuperheater AUTO Control . 1) Floor Pressure 2-2-1 CCPP , Floor Pressure GTG 1 NOx Load Floor Pressure . 50% Load , GTG 1 50% Load STG Inlet Governor Valves Throttling Floor Pressure , Load STG Inlet Governor Valves Full Open Sliding Pressure . Floor Pressure Inlet Governor Valve Throttling Loss , STG , .

- STG , STG .

- , Floor Pressure , HRSG HP Drum Thermal Stress , HRSG .

Floor Pressure STG Inlet , Start-up Curve Drum Drum Floor Pressure . HP Steam HP Drum , HP Superheater STG , Start-up Curve . , Temperature Ramping Rate Start-up Curve HP Drum Pressure . ) Floor Pressure, Pfl = 55 atg

2) Allowable HP Drum Temperature Ramping Rate Drum, Thermal Stress Temperature Ramping Rate , Start-up Mode . HP Drum Temperature Ramping Rate Start-up Curve Govern . REFERENCE PROJECT HRSG Start-up Mode Allowable Temperature Ramping Rate .

- HP drum : Cold & Warm = 3.9 oC/min., Hot = 100 oC/min. - IP drum : Cold & Warm = 10 oC/min., Hot = 100 oC/min. - LP drum : Cold & Warm = 27.8 oC/min., Hot = 100 oC/min ) 100 oC/min. .

REFERENCE PROJECT HRSG Start-up Mode .

(unit : kg/cm2g) Hot Start Warm Start Cold Start

- HP : > 63.8 > 3.51 < 3.51

- IP : > 7.67 > 0.707 < 0.707

- LP > 3.51 > 0.707 < 0.707 ) HP drum temperature ramping rate, TRR3 = 3.9 oC/min. 3) Pressure Building-up to Floor Pressure GTG Synchronization 5 HP Drum Temperature Ramping Rate HRSG Temperature Matching HP Steam Flow . HP Start-up Vent Valves Bypass Valves HP Drum Pressure Allowable HP Drum Temperature Ramping Rate Floor Pressure .

.

- Lead GTG : HRSG Temperature Matching Load . - Lead HRSG HP Drum Temp : GTG Synchronization HP Drum Temp

Allowable HP Drum Temperature Ramping Rate Floor Pressure .

- Lead HRSG HP Drum Press : HP Drum Temp

. - Lead HRSG HP Steam Flow : GTG Synchronization HP Steam Flow, Floor

Pressure HP Steam Flow Linear . , Flows HP Drum Temperature Ramping Rate Flow. Floor Pressure HP Steam Flow HRSG Temperature Matching HP Steam Flow .

- Lead HRSG HP Steam Temp : Steam Flow HP Steam Temp

Linear . Floor Pressure , Temperature Ramping , Floor Pressure Constant Pressure , 3 Constant Floor Pressure HP Steam Flow Linear . 4. STG Temperature Matching , GTG STG Temperature Matching , HRSG HP Drum Pressure Temperature, HP Steam Flow Floor Pressure STG Temperature Matching HP Steam Pressure, Flow, Temperature . STG Temperature Matching Load 3 , Linear . Floor Pressure STG Temperature Matching HP Steam Pressure, Flow, Temperature HRSG Temperature Matching HP Steam .

4. STG Lead Piping Warming-up STG Roll-up STG STG . Bypass Valves Pressure Control , STG Lead Piping Warming-up Valves Steam . Cold Start-up STG Lead Piping Warming-up Time Start-up Time . Warming-up STG Lead Piping STG . IP Steam Turbine Hot Reheat Steam IP Steam Turbine Hot Reheat Piping Warming-up Time , HP Steam Turbine HP Turbine Inlet Piping Warming-up Time . HP Turbine HP Steam Floor Pressure , Warming-up Valves , IP Turbine , Hot Reheat Steam Floor Pressure , Warming-up Valves . Warming-up Valves Steam (Choked Flow), Warming-up Valves Steam . Steam Line Warming-up Drain Valves . Drain Valves Drain Condenser , Condenser Atmospheric Drain Tank . Drain Valves , Drain Valves . , Drain Valves Discharge Piping Discharge Piping 15 oC . Drain Valves STG Lead Piping Warming-up , STG Lead Pipng STG Vent Valves Warming-up Time , Make-up Water . STG Sensing STG , STG Lead Piping Warming-up Drain Valves Vent Valves STG

Sensor (Downstream) . , Warming-up Valves , STG Sensor . Warming-up Drain Valves( Vent Valves) STG Sensor , . , STG Inlet Governor Valves Emergency Stop Valves Seat Drain Valves , STG Valves , Seat Drain Valves STG Lead Piping Warming-up . HRSG STG , STG STG Metal Temperature STG STG Roll-up Start . , IP Turbine Start REFERENCE PROJECT , STG Cold Start-up Hot Reheat 378 oC, HRSG Hot Reheat 378 oC STG Hot Reheat 228 oC STG Roll-up Start . Cold Start-up Mode IP Turbine 220 oC , 228 oC IP Turbine . Piping Steam Warming-up . , Piping Warming Steam , Piping Piping , Piping Warming Steam , Piping Warming Steam . , Piping 15 oC, Warming-up Steam 6.5 atg, 400 oC, Piping 15 oC 6.5 atg 167.1 oC , , Warming-up Valve . , . STG Lead Piping Warming-up Time . 1) Temperature Rise to Saturation Temperature

- Energy required to raise Pipe Steel Temp

E1 = Mp x Cpp x (Tsat Ti) wherein : E1 : Energy required to raise pipe steel temp Mp : Pipe steel mass Cpp : Specific heat of pipe steel Tsat : Saturation temp at inlet steam pressure Ti : Pipe initial temp ) Pipe Steel Mass Bypass Inlet ST Inlet . HRSG Bypass Inlet Bypass Steam . ) Mp = 15000 kg, Cpp = 0.12 kcal/(kg-oC), Tsat = 167 oC at 6.5 atg, Ti = 15 oC E1 = 15000 x 0.12 x (167 15) = 273,600 kcal

- Pipe Warming-up Time to Saturation Temp Time1 = E1 / Mws / (Hsatg Hsatl) wherein : Time1 : Pipe warming-up time to saturation temp Mws : Warming-up steam flow rate Hsatg : Saturation steam enthalpy at inlet steam pressure Hsatl : Saturation water enthalpy at inlet steam pressure ) Warming-up steam flow rate Warming-up Valves . Warming-up Valves (Choked Flow), , . Warming-up Warming-up Valves , Inlet . ) Mws = 3500 kg/hr, (Hsatg Hsatl) = 491.6 kcal/kg at 6.5 atg

Time1 = 273,600 / 3500 / 491.6 x 60 = 9.5 min.

2) Temperature Rise to Final Piping Temperature

- Energy required to raise Pipe Steel Temp E2 = Mp x Cpp x (Tf Tsat) wherein : E2 : Energy required to raise pipe steel temp Tf : Pipe final temp ) Tf = 228 oC E2 = 15000 x 0.12 x (228 - 167) = 109,800 kcal

- Average Temperature of Pipe Warming-up Outlet Steam Tavg = (Tf Tsat) / 2 wherein : Tavg : Average temp of pipe warming-up outlet steam Tf : Pipe final temp ) Outlet steam temp Pipe temp . 5 oC , . ) Tf = 228 oC, Tsat = 167 oC Tavg = (228 167) / 2 = 197.5 oC

- Pipe Warming-up Time to Pipe Final Temp

Time2 = E2 / Mws / (Hs Havg) wherein :

Time2 : Pipe warming-up time to pipe final temp Hs : Inlet steam enthalpy Havg : Steam enthalpy at Tavg and inlet steam pressure ) Mws = 3500 kg/hr, Hs = 780.7 kcal/kg, 400 oC at 6.5 atg, Havg = 677.5 kcal/kg, 197.5 oC at 6.5 atg Time2 = 109,800 / 3500 / (780.7 677.5) x 60 = 18.2 min.

3) STG Lead Piping Warming-up Time Time_warm = Time1 + Time2 + Time_margin wherein : Time_warm : STG lead piping warming-up time Time_margin : Marginal time for uncertainty ) , 5 Marginal Time . ) Time_warm = 9.5 + 18.2 + 5 = 32.7 min. HRSG Temperature Matching Bypass Valves , STG Lead Piping Warming-up . STG Temperature Matching STG Roll-up Start , STG Lead Piping Warming-up Warming-up STG Roll-up Start . , HRSG Temperature Matching , Warming-up Time STG Temperature Matching STG Roll-up , STG Temperature Matching STG Lead Piping Warming-up STG Roll-up . HP Drum Pre-warming STG Lead Piping Warming-up Start-up Time . 5. STG Roll-up to FSNL

STG Temperature Matching STG Lead Piping Warming-up , STG Control System Start-up Signal STG . Start-up Signal STG Control System STG Speed FSNL(Final Speed No Load) , Cold Start-up Soaking Time . STG Roll-up STG Start-up Curves . 6. STG Synchronization STG FSNL Soaking , STG Grid Synchronization Grid STG Minimum Load Loading . IP Steam Turbine STG , Synchronization STG , ICV to CV Transfer IP Turbine Governor Valves HP Turbine Governor . ICV to CV Transfer Transfer . REFERENCE PROJECT Cold Start-up Mode , STG Synchronization Load 3% MCR Load, ICV to CV Transfer STG Load 3% MCR Load 8% MCR Load 5% Load / min. Loading . STG Loading GTG STG Temperature Matching Load , GTG 1 STG Temperature Matching Load STG Loading . , STG Minimum Load (IP Turbine ICV to CV Transfer Load) Bypass Valves Minimum Opening . Cold Start-up STG Temperature Matching Load , Cold Start-up , . 7. STG Loading to Rated HP Steam Temperature STG Synchronization( ICV to CV Transfer) , Bypass Valves Forced Close HRSG STG , GTG Load NOx Emission Guarantee , GTG 50% Load , HP Steam

Temperature Rated Temperature HP Steam Temperature Ramping Rate STG Rate . REFERENCE PROJECT Cold Start-up , STG ICV to CV Transfer HP Steam Temperature 378 oC, 2.5 oC/min. Rated HP Steam Temperature 578 oC GTG Temperature Matching Mode . , GTG Load Control Loading , Temperature Matching Reference Temperature 578 oC, Temperature Matching Ramping Rate 2.5 oC/min. GTG Temperature Matching Control ON , GTG Exhaust Gas Temperature Control Mode GTG Loading. GTG Loading Control Loading , GTG Exhaust Gas Temperature Control , STG Load Hold Loading . 8. GTG Loading to 50% Load STG Loading to Rated HP Steam Temperature , GTG Load NOx Emission Guarantee , GTG 50% Load, STG STG Load Ramping Rate . 9. Lag GTG Loading to 50% Load GTG Lead GTG, Lag GTG Lead GTG 50% Load 50% Load , Lead GTG 50% Load Lag GTG Addition . Lag GTG 50% Load STG , HRSG 50% Load . , GTG Synchronization HRSG Temperature Matching , Reheat Cycle Reheat Piping Cooling Steam , Allowable HP Drum Temperature Ramping Rate HP Pressure Floor Pressure , Lag GTG Load Control 50% Load GTG Maximum Ramping Rate Ramping Rate . Lag GTG Maximum Ramping Rate , HRSG Superheat/Reheater Attemperator Temperature Control Drum Level Control .

10. Lag GTG Addition Lead GTG 50% Load , 50% Load Lag GTG Isolation Valves , Lag HRSG Bypass Valves Forced Close, Lag HRSG STG . STG Loading Rate STG Lag HRSG Bypass Valves Closing Rate . 11. Both GTGs Loading to 100% Load Lag GTG Addition , Both GTGs STG Loading Rate 100% Load . , STG Loading Rate GTG Loading Rate, Lag GTG Addition Both GTGs 100% Load 7, 8 . , GTG Loading Rate , GTG 100% Load HRSG GTG Load , STG 100% Load .(STG Saturation) GTG MCR Load , STG MCR Load . , STG Saturation Time . Start-up Time , MCR Load , GTG Base Load Start-up Time . Start-up Curves . ()