Transcript Slide 1
STEAM BOWING PROCEDURE OF STAGE # 1 OBJECTIVE AND PRINCIPLE OF STEAM BLOWING STEPS INVOLVED IN STEAM BLOWING ( WITH PATH DIAGRAM) PROCEDURE OF PRE-STEP STEAM BLOWING PROCEDURE OF MAIN STEP STEAM BLOWING COMPLETION CRITERIAN OF STEAM BLOWING PHOTOS OF SIPAT U # 1 STEAM BLOWING OBJECTIVE The purpose of steam line blowing is to remove pipe slag, weld bead deposits and other foreign material from the main and reheat steam systems prior to turbine operation. The cleaning is accomplished by subjecting the piping systems to heating, blowing steam and cooling cycles in sufficient number and duration until clean steam is obtained. PRINCIPLE OF STEAM BLOWING To ensure that sufficient cleaning forces are applied to the piping, the steam momentum during the steam blow must be equal to or greater than the steam momentum at normal maximum load condition. The Cleaning Force Ratio (CFR) is typically used to evaluate if satisfactory blow conditions are obtained. CFR = ( vb / vmcr ) x ( Fb / Fmcr )2 > 1.00 Where vb = specific volume at steam blowing condition vmcr = specific volume at maximum load condition Fb = steam mass flow rate at blowing condition Fmcr = steam mass flow rate at maximum load condition STEPS OF STEAM BLOWING PRE STEP # 1 : Separator – SH - main steam line- Temporary pipe - martyr valve - tailpipe to atmosphere. PRE STEP # 2 : Separator - main steam line- HPBP – CRH Line – CRH Isolator - martyr valve tailpipe to atmosphere. MAIN STEP # 1 : Separator-SH-main steam line-MSV-temporary pipe with martyr-valve-NRV-CRH-RHHRH-IPT Stop Valve-temporary pipe-target-tailpipe to atmosphere MAIN STEP # 2 : Separator-SH-main steam line-MSV-temporary pipe with martyr-valveNRV-CRHRH-HRH-LP Bypass valve-temporary pipe-tailpipe to atmosphere PRE STEP PROCEDURE Start the Boiler as per normal working principle Raise the Seaprator Pressure to 40 Ksc At 40 Ksc Shut all Fuel Burners in service Stop The BRP Pump Open The Martyr Valve Let the pressure fall to 20 Ksc Close The Martyr Valve COMPLETION CRITERIA Clean White Smoke to be observed at the Exhaust of Tail Pipe NOTE : CFR < 1.0 AND NO TARGET PLATE IS TO BE USED DURING THIS STEP First Blow at every Step to be given at much reduced pressure to check the temporary piping healthiness MAIN STEP PROCEDURE Start the Boiler as per normal working principle Raise the Seaprator Pressure to 80 Ksc ( SH O/L Temp : 370 C) At 80 Ksc Shut all Fuel Burners in service Stop The BRP Pump Open The Martyr Valve Let the pressure fall to 40 Ksc Close The Martyr Valve Maintain the Separator Storage Tank Level Light The Boiler For Next Blowing o NOTE : CFR > 1.0 AND NO TARGET PLATE IS TO BE USED DURING THIS STEP First Blow at every Step to be given at much reduced pressure to check the temporary piping healthiness COMPLETION CRITERIAN A Target Plate is used to access the impacts of particle during steam Blowing. Steam Blowing will be declared when No impacts with an diameter larger than 1 mm Not more than 4 impacts with an diameter larger than 0.5 mm Not more than 10 impacts with an diameter of 0.2 to 0.5 mm Pre Step # 1 : MS Line Steam Blowing ESV MSV Martyr V/v ESV MSV HP Bypass Final SH MS Line CRH Drain Pot CRH NRV IP SV HRH Line CRH Line RH O/L Hdr Open Close Martyr Valve LP Bypass Final SH Martyr V/v LPBP V/ v Steam Blow Line Temporary Line Pre Step # 2 : HPBP / CRH Line Steam Blowing ESV MSV Martyr V/v MS Line ESV MSV HP Bypass CRH Drain Pot CRH NRV IP SV HRH Line CRH Line RH O/L Hdr Open Close Steam Blow Line Temporary Line Martyr Valve LP Bypass Final SH Final SH Martyr V/v Main Step # 1 : HRH Line Steam Blowing ESV MSV Martyr V/v MS Line ESV MSV HP Bypass CRH Drain Pot CRH NRV IP SV HRH Line CRH Line RH O/L Hdr Open Close Steam Blow Line Temporary Line Martyr Valve LP Bypass Final SH Final SH Martyr V/v Main Step # 2 :LPBP Line Steam Blowing ESV MSV Martyr V/v MS Line ESV MSV HP Bypass CRH Drain Pot CRH NRV IP SV HRH Line CRH Line RH O/L Hdr Open Close Steam Blow Line Temporary Line Martyr Valve LP Bypass Final SH Final SH Martyr V/v From Separator To Separator From Separator STORAGE TANK SH D.S.H. No1 Click Here Sample Cooler Blow Down Tan FLASH TANK MIXING PIECE WR BRP ZR ECO MIXING LINK SH COMMN DRAIN LINE CRH DRAIN LINE CHEM CLEANING SYS BLR FILL PUMP TO ECO FROM FEED WATER TO DRAIN HDR WATER CIRCULATION SYSTEM Modification # 2 1 To D/A Floor From Storage Tank FLASH TANK ZR WR Condensor From Service Water Condensor Dummy Temporary Connection To Station Drain