Power Sector Eastern Region

Best Practices Workshop 20th and 21st April 2009

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1. SHORT CYCLE STEAM BLOWING WITH AN AIM TOWARDS OPTIMISING TOTAL ERECTION & COMMG CYCLE DURING THE PERIOD BETWEEN BOILER CHEMICAL CLEANING TO SYNCHRONISATION PROCEDURE:a)

NON INSTALLATION OF 2 M STRAIGHT PIECE BELOW ESV AND IV. (THESE WILL BE MECHANICALLY CLEANED IN PRESENCE OF CUSTOMER) LAYING OF LOOP LINES FROM MS LINE END (WITHOUT ABOVE STRAIGHT PIECE) UPTO CRH LINE END AT NRV DOWN STREAM SIDE (CRH NRV IS REMOVED) LAYING OF TEMPORARY EXHAUST PIPE FROM HRH LINE END (WITHOUT ABOVE STRAIGHT PIECE) OR LPBP LINE END UPSTREAM OF LPBP VALVE (WITHOUT INSTALLING LPBP VALVE) COMPLETION OF BLOWING IN 2 STAGES.

b)

c)

d)

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ADVANTAGES OVER EXISTING METHODS:a) b) c) d)

SHORT CYCLE STEAM BLOWING. LESS AMOUNT OF TEMPORARY PIPING. ERECTION PERIOD IS LESS. PIPE FLOATING WITH ESV AND IV WILL BE CARRIED OUT DURING PIPING RESTORATION PERIOD. TURBINE OIL SYSTEM ACTIVITIES LIKE BARRING GEAR AND GOVERNING SYSTEM ADJUSTMENT CAN BE CARRIED OUT PARALLELY DURING STEAM BLOWING PERIOD

ANTICIPATED BENEFITS:a) b)

CYCLE TIME REDUCTION = 10 DAYS COST SAVING = Rs 100000/-

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2. CLEANING OF FUEL OIL SYSTEM BY DIAPHRAGM BLASTING METHODPROCEDURE:a)

IDENTIFICATION OF ZONES OF BLOWING AND HEADER END BLANK FLANGES EXTENSION OF COMPRESSED AIR LINE/ HOSE TO ONE END OF PIPING WITH A ISOLATION VALVE REPLACEMENT OF BLANK FLANGES WITH THROUGH FLANGES WITH DIAPHRAGM MADE OF CARD BOARD OR GROOVED GASKET. INITIALLY AIR FLUSHING WITHOUT DIAPHRAGM FOLLOWED BY DIAPHRAGM BLASTING. PRESSURE INSIDE PIPING IS BUILT UP AND THEN SUDDENLY DIAPHRAGM RUPTURES. 7 TO 8 BURSTS ARE SUFFICIENT.

b)

c)

d)

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ADVANTAGES OVER EXISTING METHODS:a) b) c)

NO ACID CLEANING ARRANGEMENT (PUMPS, VALVES, PIPING ETC) NO STEAM BLOWING ARRANGEMENT, AUXILIARY BOILER OR EXTERNAL SOURCE OF STEAM. MOST SUITABLE FOR GREEN FIELD PROJECT.

ANTICIPATED BENEFITS:a) b) c)

CYCLE TIME REDUCTION = 7 DAYS COST SAVING = Rs 100000/QUALITY : a) BETTER CLEANING b) NO CONDENSATE OR ACID ACCUMULATION IN PIPELINES OR DEAD POCKETS

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3. BYPASSING OF DEAERATOR DURING PREBOILER SYSTEM ALKALI FLUSHING PROCEDURE:a)

DIRECT LOOPING BETWEEN BFP BOOSTER PUMP SUCTION LINE END AT DEAERATOR ENTRY ( NOT TO BE TERMINATED TO DEAERATOR) WITH BFP RECIRCULATION LINE / CONDENSATE LINE END ENTERING DEAERATOR (NOT TO BE TERMINATED TO DEAERATOR) ERECTION OF OTHER PIPING NETWORK AS PER SCHEME. CONDUCTANCE OF PREBOILER SYSTEM CLEANING WITH DETERGENT CLEANING OF STORAGE TANK INTERNAL SURFACE MAUNALLY BY RUBBING WITH COTTON WASTE OR MARKIN CLOTH WITH APPLICATION OF DETERGENT WHEREVER RUSTING / ADHERENT DEBRIS IS NOTICED

b) c) d)

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ADVANTAGES OVER EXISTING METHODS:a) b) c)

d)

NO CLOGGING OF DEAERATOR TRAY NO PRESSURISATION OF DEARATOR. DEAERATOR INTERNAL SURFACE CAN BE CLEANED PARALLELY DURING DETERGENT FLUSHING WITH PHYSICALCHECKING OF CLEANLINESS LESS AMOUNT OF DM WATER AND CHEMICAL CONSUMPTION.

ANTICIPATED BENEFITS:a) b)

COST SAVING = 50% OF CHEMICALS i.e. Rs 30000/- AND DM WATER = 180 TON QUALITY = BETTER CLEANING BECAUSE OF DIRECT MANUAL SCRUBBING.

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4. UTILISATION OF SODA ASH/ CAUSTIC LYE INSTEAD OF LIME FOR EFFULENT TREATMENT DURING ACID CLEANING PROCEDURE:a)

IDENTIFICATION OF NEUTRALISING PIT AND ASSOCIATED SYSTEM DRAINAGE LAYOUT. ESTIMATION OF QUANTITY FOR NEUTRALISATION OF CHEMICALS DURING STAGES OF ACID CLEANING AND PROCUREMENT ACTION DURING EFFLUENT DISPOSAL FROM BOILER, DIRECT FEEDING TO NEUTRALISING PIT BY MANUAL MEANS

b)

c)

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ADVANTAGES OVER EXISTING METHODS:a) b)

EASY HANDLING , LESSER QUANTITY OF CHEMICALS (ALMOST ONE THIRD OF LIME). HOMOGENIOUS MIXING WITH EFFLUENT. HENCE EFFECTIVE CONTROL OVER EFFLUENT QUALITY. WITH LIME PROPER MIXING COULD NOT BE ENSURED AND PH VALUE OF 8 COULD NOT BE ASSURED CONTINUOUSLY.

ANTICIPATED BENEFITS:COST SAVING = RS 20000 (PRICE DIFFERENCE BETWEEN LIME AND SODA ASH) b) QUALITY = STRICT ADHERENCE TO POLLUTION CONTROL NORM THROUGHOUT THE ACID CLEANING PROCESSa)

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5. UTILISATION OF NITROGEN TANKER INSTEAD OF NITROGEN CYLINDERS DURING ACID CLEANING PROCEDURE:a) LAYING OF SINGLE LINE FROM DRUM VENT UPTO BOILER ZERO

METER WITH ONE ISOLATION VALVE ONLY.a) CONNECTION OF TANKER OUTLET LINE WITH NITROGEN LINE

COMING FROM DRUM VENTb) FEEDING FROM TANKER TO BOILER THROUGH DRUM VENT AS AND

WHEN REQUIRED WITH ADJUTMENT OF PRESSURE.

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ADVANTAGES OVER EXISTING METHODS:a) EASY INSTALLATION. NO SEPARATE HEADER WITH MULTIPLE NUMBER OF CYLINDERS, VALVES AND REGULATORS ARE REQUIRED. b) VERY LESS NUMBER OF OPERATING PERSONNEL REQUIRED ( ONE OR TWO). c) NITROGEN CONSUMPTION IS OPTIMUM. d) READY FOR OPERATION IN CASE OF ANY EVENTUALITY.

ANTICIPATED BENEFITS:a) COST SAVING = RS 20000 ( GAS + MANPOWER) b) QUALITY = NITROGEN CAPPING IS OPTIMUM LEAVING NO CHANCE OF EXTERNAL AIR INGRESS. c) EASE OF OPERATION.

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6. ADOPTION OF ELECTROSTATIC CLEANING MACHINE FOR HP

BYPASS SYSTEM AND ID/FD/PA/BFP/MILL OIL FLUSHING PROCEDURE:a) b)

INSTALLATION OF SAME WITH BOTH INLET AND OUTLET HOSE CONNECTED TO TANK THROUGH TOP/SIDE/BOTTOM OPENINGS. RUN THE PUMP FOR FILLING THE MACHINES TANK. ONCE FILLED, CHARGE THE FIELD.

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ADVANTAGES OVER EXISTING METHODS:a) EASY HANDLING , NO SEPARATE FILTERATION ARRANGEMENT FOR

TANK OIL b) LESS NUMBER OF FILTERS FOR SYSTEM FLUSHING

ANTICIPATED BENEFITS:a) CYCLE TIME REDUCTION = 4 DAYS b) QUALITY = SUPERIOR CLEANING WITH ADHERENCE TO NASH NORMS

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7. INTRODUCTION OF MODIFIED OIL FLUSHING PROCEDURE FOR TG OIL SYSTEM PROCEDURE :a)

b) c) d) e) f)

PRESSURE TEST OF LUB OIL, GOVERNING OIL, JACKING OIL AND TURNING GEAR OIL LINES WITH NITROGEN AT 1.5 TIMES WORKING PRESSURE. AIR BLOWING OF INDIVIDUAL CIRCUIT PRIOR TO START OF OIL FLUSHING CONDUCTANCE OF OIL FLUSHING IN TWO STEPS : PRIMARY (WITH FLUSHING OIL)& SECONDARY (WITH FRESH OIL) ARRANGEMENT OF HEATING EQUIPMENT FOR THERMAL SHOCKS (OPTIONAL) INTRODUCTION OF 200 MESH SPECIAL TYPE NYLON NET BAGS AT THE END OF LUB OIL DRAIN HEADER INSIDE MOT AND JACKING OIL HOSE ENDS. INTRODUCTION OF LUB OIL THROTTLE STRAINERS OF SIZES 80,120,200 AND 400 MESH.

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ADVANTAGES OVER EXISTING METHODS:a) NO ACID CLEANING PRIOR TO OIL FLUSHING IS REQUIRED. b) CENTRIFUGE NEED NOT BE OPERATED DURING OIL FLUSHING. c) THERMAL SHOCK IS OPTIONAL.

ANTICIPATED BENEFITS:a) CYCLE TIME REDUCTION = 30 DAYS BECAUSE OF INTRODUCTION OF AIR BLOWING b) COST SAVING = Rs 100000/- BY WAY OF AVOIDING ACID CLEANING c) QUALITY = SUPERIOR CLEANING DUE TO UTILISATION OF SPECIAL TYPE NYLON NETS

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8. INTRODUCTION OF ROTARY SAMPLER FOR MILL OPTIMISATION PROCEDURE:a) PREPARATION OF TAPPING POINTS AS PER VENDOR MANUAL. b) CONNECTION OF THE SET UP INCLUDING PROBE, CONTROL BOX , INSTRUMENTA ETC AS PER MANUAL. c) TRAVERSING THE PROBE INSIDE COAL PIPING AND COLLECTING PF SAMPLE THROUGHOUT CROSS SECTION OF COAL PIPING

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ADVANTAGES OVER EXISTING METHODS:a) REPRESENTATIVE SAMPLE IS COLLECTED FROM TOTAL CROSS SECTION OF COAL PIPING INSTEAD OF EARLIER PRACTICE OF LINE TRAVERSING. EFFECT OF ROPING OVER SAMPLE COLLECTION IS ELIMINATED. b) EXACT PICTURE OF MILL PERFORMANCE IS KNOWN.

ANTICIPATED BENEFITS:a) b) AIDS IN PROPER MILL OPTIMISATION. CLASSIFIER ADJUSTMENT IS ACCURATE BASED ON THE RESULT.

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9. INTRODUCTION OF NON- CONTACT TYPE FLOWMETER FOR FLOW OPTIMISATION DURING OIL FLUSHING PROCEDURE:a) IDENTIFICATION OF INDIVIDUAL CIRCUIT WHERE FLOW/VELOCITY IS TO MEASURED. b) OPTIMISATION OF FLOW/VELOCITY BY INTRODUCING ORIFICE OR THROTTLING INLET VALVE TO EACH CIRCUIT/ LINE.

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ADVANTAGES OVER EXISTING METHODS:a) FLOW/VELOCITY THROUGH EACH CIRCUIT IS KNOWN. b) POOR FLOW THROUGH A CIRCUIT IS IDENTIFIED WHICH WAS NOT KNOWN EARLIER.

ANTICIPATED BENEFITS:a) BETTER FLUSHING OF EACH AND EVERY LINE.

b)

FLUSHING CYCLE IS REDUCED BECAUSE OF BETTER FLOW THROUGH EACH CIRCUIT.

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10. OPTIMISATION/MINIIMISATION OF STEAM DUMPING PERIOD PROCEDURE :a) ON COMPLETION OF STEAM BLOWING ACTIVITY, BOILER, DEAERATOR, RELATED PIPINGS AND HOT WELL ARE DRAINED OFF TOTALLY. PHYSICAL CLEANING OF DEAERATOR AND HOTWELL ARE RESORTED TO. CUSTOMER IS ASKED TO DRAIN CONDENSATE STORAGE TANK (MOSTLY IT IS UNDER CUSTOMER SCOPE) ESPECIALLY IF IT IS A NEW ONE AND CLEAN IT PHYSICALLY. BOILER AND DEAERATOR IS NOT FILLED WITH DM WATER FROM CST OUTLET TILL ITS PURITY MATCHES WITH SPECIFIED QUALITY. MASS FLUSHING/ STEAM BLOWING OF LINES IS CONDUCTED, WHICH WERE HITHERTO NOT CLEANED BUT COMES UNDER STEAM DUMPING CIRCUIT. HP AND LP DOZING SYSTEM ARE COMMISSIONED AND MADE AVAILABLE FOR SERVICE IN ALL RESPECT.

b)

c) d) e)

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f)

HP-LP BYPASS ARE COMMISSIONED AND MADE AVAILABLE FOR SERVICE IN ALL RESPECT FOR CONTINUOUS OPERATION. BOILER LOW POINT BLOWDOWN IS RESORTED AT 5, 15, 25 KG/CM2 PRESSURE WHILE STEAMING UP THE BOILER FOR STEAM DUMPING ACTIVITY. BOILER WATER PURITY IS MAINTAINED THROUGH CONTINUOUS DOZING AND CBD OPERATION. ALL THE OIL GUNS ARE MADE AVAILABLE. AVAILABILITY OF ONE OR TWO MILLS WILL BE ADDED ADVANTAGE. COAL FIRING WILL HASTEN THE DUMPING PROCESS. CONDENSATE LINE FROM CEP DISCHARGE TO DEAERATOR IS ISOLATED AND HOTWELL WATER IS DUMPED FROM CEP DISCHARGE PREFERABLY THROUGH A TEMPORARY TAPPING FROM EXCESS RETURN LINE TO CANAL. UNDER NO CIRCUMSTANCE THIS WATER SHOULD GO TO DEARERATOR. MAKE UP WATER IS GIVEN TO DEAERATOR DIRECTLY. STEAM DUMPING PROCESS CONTINUES WITHOUT INTERRUPTION WITH MAXIMUM POSSIBLE STEAM FLOW (PREFERABLY 20-30% MCR FLOW) AND PRESSURE ABOVE 40 KG/CM2( FOR SETS ABOVE 60 MW). DM WATER SYSTEM SHOULD BE PREPARED TO CATER TO CORRESPONDING MAKE UP QUANTITY ON A CONTINUOUS BASIS. HOTWELL SHOULD BE PHYSICALLY CLEANED AFTER OR DURING (DUMPING ACTIVITY TO BE STOPPED FOR SOME TIME) STEAM DUMPING ACTIVITY FOR SMOOTH OPERATION OF SUBSEQUENT ACTIVITIES.

g)

h)

i)

j)

k)

l)

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ADVANTAGES OVER EXISTING METHODS:a) LESS NUMBER OF STEAM DUMPING PERIOD (USUALLY WITHIN 2 DAYS). b) COMMG CYCLE TIME IS LESS.

ANTICIPATED BENEFITS:a) LESS AMOUNT OF DM WATER, FUEL OIL AND AUX POWER CONSUMPTION. b) OPTIMISED COMMISIONING CYCLE. c) CUSTOMER CONFIDENCE ON METHODOLOGY ADOPTED BY BHEL FOR CLEANING OPERATIONS LIKE CHEMICAL CLEANING AND STEAM BLOWING.

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11. INCLUSION OF EQUIPMENT COOLING WATER SYSTEM IN DETERGENT FLUSHING CIRCUIT PROCEDURE:a) LOOPING OF SUPPLY AND RETURN HEADER AT END POINT, PHE INLET AND OUTLET END (BYPASSING PHE), TEMPORARY .DETERGENT SUPPLY AT PUMP DISCHARGE FLANGE AND SYSTEM RETURN FROM PUMP SUCTION (PUMP REMOVED FROM POSITION. b) TEMPORARY CHEMICAL CIRCULATION PUMP RUNS TO CIRCULATE DETEGENT THROUGH DMCW DISCHARGE BYPASSING PHE, SUPPLY HEADER, RETURN HEADER AND RETURN BACK TO TEMPORARY TANK.

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ADVANTAGES OVER EXISTING METHODS:a) BETTER CIRCULATION OVER CONVENTIONAL GRAVITY FLUSHING. b) REMOTE POSSIBILITY OF FOREIGN MATERIAL REMAINING IN CIRCUIT. c) REMOVAL OF ADHERENT RUST, DEBRIS, OILY MATTER THROUGH DETERGENT ACTION. d) NO CHOKING OF PHE AT LATTER STAGE.

ANTICIPATED BENEFITS:a) EXCELLENT CLEANING. b) CHANCE OF POST COMMG EQUIPMENT DAMAGE IS REMOTE .

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12. LIMITING HPBP CONTROL VALVE OPENING WITH RESPECT TO AMOUNT OF LOAD FOR LEAST SYSTEM DISURBANCE IN CASE OF LOAD THROW OFF. 13. UTILISATION OF DETERGENT (SNID-PGN) FOR CONDENSER TUBE EXPANSION 14. MEASURES FOR HIGH VACUUM AND SINGLE EJECTOR/ VACUUM PUMP OPERATION 15. CHANGES IN EDTA CLEANING PROCESS FOR BETTER CLEANING AND PASSIVATION

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14. MEASURES FOR HIGH VACUUM AND SINGLE EJECTOR/ VACUUM PUMP OPERATION

PROCEDURE Steady Aux. Steam Pr. And Temp. was maintained Correctness of Main Ejector Siphon drain loop was ensured Starting ejector air valve passing was attended to minimize air ingress. Physical checking of all joints & tapping points and marking those on PID/ERN. Drgs (FUJI method of monitoring work completion) was done and system completion was ensured. Special care was taken to ensure proper welding of Steam Throw off Device with Condenser. No leakage was left unattended during water fill test of the system with 100% instruments in service (which are major leakage area and generally being erected after water fill test). As water level can not be raised beyond a specified limit. Heaters with drip line, vent line up to condenser were filled with water (using DM Make-up pump discharge tapping) keeping all heater instruments into service. This activity helps in better heater level measurement also. All Thermo wells are welded (though not specified in Drg.) All Steam Traps were provided as per drg/design to avoid unwanted heat load to condenser. This improved heat rate too.28

FUJI ensured proper closing of MAL. Drains. BHEL Site also ensured proper closing of drain valves connected to condenser. No steam passing/leaking sound was heard near HP/LP flash tank. This improved heat rate too. Regular cleaning of Debris Filter was done. BENEFITS Single ejector operation. The air flow measured at ejector exhaust has been recorded as minimum as possible (3.5 to 4.0 kg/hr only) against handling capacity of single main ejector of 40 to 50 Kg/hr . Excellent vacuum and minimum system loss (less than 0.6%) which further reduced entry of dissolved air with make up water. Excellent result in PG Test . Heat rate is better than design one (1.6% better) even after 2 years operation of unit-1

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15. CHANGES IN EDTA CLEANING PROCESS FOR BETTER CLEANING AND PASSIVATION

PROCEDURAL CHANGES a) Alkali Flushing at enhanced pressure: Boiler was filled upto normal level of drum with 0.1% Trisodium Phosphate and 0.05% Disodium Phosphate treated water. Boiler pressurewas raised upto 10 kg/cm2 by lighting up and maintained for 4 hours for effectivedigestion of chemicals b) Hot water rinse: Boiler is lighted up and water temp is raised to 1400C and maintained at same temp for 1 hour by continuing firing. Thereafter boiler is tripped and fans kept running. Once water temp reaches 950C, boiler is hot drained. c) Cold water rinse: Boiler was flushed with cold water by continuous filling and dumping process till phosphate ppm became less than 10. d) Acid cleaning & Passivation: Batch of 45 m3 chemical solution of EDTA, hydrazine, BHELSOL and BHELMAX was prepared at a time and in four batches itself boiler could be filled. e) Treated DM water rinsing: Process followed is similar to Jojobera IV. f) Existing permanent drum water level gauge was utilized thoughout the total process. Less number of waterwall metal temperature monitoring thermocouples were used. g) Air Bubbling network was made more widespread. was possible.

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BENIFITS: a) More amount of loose iron oxides, debris and oily substances got removed during alkali flushing process because of treatment at high pressure and temperature. Unnecessary reaction of EDTA with loose materials is avoided. Adherent oxides also became semi loosened because of detergent action thus making subsequent EDTA reaction easier. b) Batch filling was easier with less time and less monitoring of chemical percentage. c) Total dissolution of iron oxide is ensured with the existing hydrazine quantity because of less quantity of iron oxides and higher contact period of chemicals with boiler metal at 1400C by maintaining firing. d) Effective cleanliness was evident during inspection of drum inside. Consolidation of tightly bonded magnetite was observed in the test coupans which were placed inside drum e) Reduction in monitoring appliances thus making the preparation process simpler. f) Stringent quality inspection process ensured good chemical quality. g) Uniform and effect neutralization

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