Devdeep Bose DGM ( Commng & Testing)
• INTRODUCTION TO SUPER CRITICAL UNI -
POINTS OF DISCUSSION SUB CRITICAL & SUPER CRITICAL BOILER SIPAT BOILER DESIGN SIPAT TURBINE DESIGN DESIGN PARAMETERS COMMISSIONING PRE COMMISSIONING PROBLEMS POST COMMISSIONING PROBLEM
COMPARISION OF 660 MW Vs 500 MW BOILER Description unit 660 500 S/H STEAM FLOW T/HR 2225 1625 KG/CM 2 SH STEAM PR 256 179 SH STEAM TEMP 0 C 540 540 RH STEAM FLOW T/HR 1742 1397.4 0 C RH STEAM TEMP INLET 303.7 338.5 RH STEAM TEMP OUTLET 0 C 568 540 KG/CM 2 RH STEAM PRESS INLET 51.17 46.1 0 C FEED WATER TEMP 291.4 255.2
Tonnage Comparison Description 660 MW 500 MW 9200 Structural Steel Erection 7383 5300 Boiler Proper & Accessories (Pre. Parts) 7080 2000 Refractory, Insulation & Cladding 1410 2200 Power Cycle Piping 3032 76 Soot Blowing System 54 2000 Coal Firing System 3573 5200 Draft System 5275 200 Fuel oil system 62 280 Miscellaneous System 130 380 Electrical & Instrumentation 282 28281 26836 TOTAL
Material Comparison Description 660 MW 500 MW Carbon Steel Structural Steel Alloy Steel Carbon Steel Water wall T22 T11, T22 SH Coil T23, T91 T22, T91,T11 RH Coil T91,Super 304 H T11 LTSH T12 Carbon Steel Economizer SA106-C 24,000 Nos Welding Joints (Pressure Parts) 42,000 Nos
Structural Comparison Slno 660 MW 500 MW Remarks 1 STRUCTURALS a Advantages (660MW) of Bolting structure : Entire structural is bolting type- o Fast in erection. entire structure is bolted. Holes Structural is o Clean environment are drilled on the columns and assembled at site o No Welding network required gusset plates, and supplied with with welding o Safety at site matching plates. o Painting finish is good o ( No Weld surface) b. No Welding work involved in Assembly is carried Can be dismantled if required assembly/ Erection , except out with Welding ( For Maintenance purpose) Walkway rail post welding c Material supply is tier wise Material is supplied Erection completion tier wise, including staircases, railing, as per the erection including gratings, platforms , gratings etc. sequence. staircases etc.
COST COMPARISON 1 Cost of SG Package 1970.73 Cr 1020.54 Cr with ESP 2 Cost of ESP 183.54Cr 3 Total cost of Boiler + ESP 2154.27 Cr 1020.54 Cr 1.09 Cr 1.02 Cr 4 Cost of Boiler per MW with ESP 5 Cost of TG for entire stage 1204.72 Cr 634.31 Cr 0.6Cr 0.63 Cr 6 TG cost per MW
BOILER SPECIFICATION Description unit S/H STEAM FLOW T/HR 2225 SH STEAM PR KG/CM 2 256 0 C SH STEAM TEMP 540 RH STEAM FLOW T/HR 1742 0 C RH STEAM TEMP INLET 303.7 RH STEAM TEMP OUTLET 0 C 568 KG/CM 2 RH STEAM PRESS INLET 51.17 0 C FEED WATER TEMP 291.4
= Boiler Efficiency Quoted Turbine Heat Rate 100% TMCR 86.27% 100% Load 1904 Kcal / KWH 80% TMCR 86.60% 80% Load 1924 Kcal / KWH 60% TMCR 86.68% 60% Load 1973 Kcal / KWH 50% TMCR 86.91% 50% Load 2065 Kcal / KWH Net Plant Heat Rate = NTRH = 2207 KCal / KWHR ( at 100% TMCR) 80% TMCR = 2222 Kcal / KWHR 60% TMCR = 2276 Kcal / KWHR 50% TMCR = 2376 Kcal / KWHR Plant Efficiency at 100% TMCR = 38.96% 80% TMCR = 38.7 % 60% TMCR= 37.78% 50% TMCR = 36.19%
Supplier : M/s DOOSAN Erection By : M/s L&T
UNDERSTANDING SUPER CRITICAL TECHNOLOGY When Water is heated at constant pressure above the critical pressure, its temperature will never be constant No distinction between the Liquid and Gas, the mass density of the two phases remain same No Stage where the water exist as two phases and require separation : No Drum The actual location of the transition from liquid to steam in a once through super critical boiler is free to move with different condition : Sliding Pressure Operation For changing boiler loads and pressure, the process is able to optimize the amount of liquid and gas regions for effective heat transfer.
SUPER CRITICAL BOILER CYCLE WITH SH, RH & Regeneration 3 1 TEMP 568’C 540’C 600 500 Steam flow :2225 T/Hr 2 400 : 540 ‘c Steam temp Steam Pres : 256 kg/cm2 RH pre : 51.6 Kg/cm2 300 : 568’c RH Temp : 291’c Feed water Temp 200 100 5 4 0 ENTROPY
540 ° C, 255 Ksc 568 ° C, 47 492 ° C, 260 Ksc Ksc 457 ° C, 49 Ksc FUR ROOF ECO HGR I/L HDR O/L HDR HRH LINE MS LINE 411 ° C, 411 ° C, 277Ksc 275 Ksc SEPARATOR S T FINAL SH FINAL O LTRH RH R DIV PANELS SH A PLATEN SH G E VERTICAL WW T A G 305 ° C, 49 Ksc ECO N JUNCTION K HDR LPT LPT IPT C HPT O N ECONOMISER D E N S E R ECO I/L FEED WATER BWRP 290 ° C, 302 KSC FUR LOWER HDR FRS
Steam Partial Steam Generation Complete or Once-through Steam Generation Heat Input Water Heat Input Water Water Boiling process in Tubular Geometries
SIPAT SUPER CRITICAL BOILER BOILER DESIGN PARAMETER DRUM LESS BOILER : START-UP SYSTEM TYPE OF TUBE Vertical Spiral SPIRAL WATER WALL TUBING Advantage Disadvantage over Vertical water wall
Vertical Tube Furnace To provide sufficient flow per tube, constant pressure furnaces employ vertically oriented tubes. Tubes are appropriately sized and arranged in multiple passes in the lower furnace where the burners are located and the heat input is high. By passing the flow twice through the lower furnace periphery (two passes), the mass flow per tube can be kept high enough to ensure sufficient cooling. In addition, the fluid is mixed between passes to reduce the upset fluid temperature.
Spiral Tube Furnace The spiral design, on the other hand, utilizes fewer tubes to obtain the desired flow per tube by wrapping them around the furnace to create the enclosure. This also has the benefit of passing all tubes through all heat zones to maintain a nearly even fluid temperature at the outlet of the lower portion of the furnace. Because the tubes are “wrapped” around the furnace to form the enclosure, fabrication and erection are considerably more complicated and costly.
SPIRAL WATER WALL ADVANTAGE Benefits from averaging of heat absorption variation : Less tube leakages Simplified inlet header arrangement Use of smooth bore tubing No individual tube orifice Reduced Number of evaporator wall tubes & Ensures minimum water flow Minimizes Peak Tube Metal Temperature Minimizes Tube to Tube Metal Temperature difference DISADVANTAGE Complex wind-box opening Complex water wall support system tube leakage identification : a tough task More the water wall pressure drop : increases Boiler Feed Pump Power Adherence of Ash on the shelf of tube fin
BOILER OPERATING PARAMETER 2 No’S ( AXIAL ) FD FAN 11 kv / 1950 KW 228 mmwc 1732 T / Hr 2 No’s ( AXIAL) PA FAN 11 KV / 3920 KW 884 mmwc 947 T / Hr 2 No’s ( AXIAL) ID FAN 11 KV / 5820 KW 3020 T / Hr TOTAL AIR 2535 T / Hr SH OUT LET PRESSURE / TEMPERATURE / 256 Ksc / 540 C FLOW 2225 T / Hr RH OUTLET PRESSURE/ TEMPERATURE / 46 Ksc / 568 C FLOW 1742 T / Hr SEPARATOR OUT LET PRESSURE/ 277 Ksc / 412 C TEMPERATURE ECONOMISER INLET 304 Ksc / 270 C MILL OPERATION 7 / 10 COAL REQUIREMENT 471 T / Hr SH / RH SPRAY 89 / 0.0 T / Hr BOILER EFFICIENCY 87 %
Coal Analysis 1. High erosion Design Worst Best Young Hung Tangjin Unit Parameter potential for Coal Coal Coal #1,2(800MW) #5,6(500MW) pulverizer and High Heating Value kcal/kg 3,300 3,000 3,750 6,020 6,080 backpass tube is Total Moisture % 12.0 15.0 11.0 10.0 10.0 expected due to high ash content. Volatile Matter % 21.0 20.0 24.0 23.20 26.53 Proximate Analysis Fixed Carbon % 24.0 20.0 29.0 52.89 49.26 Ash % 43.0 45.0 36.0 13.92 14.21 2. Combustibility Index is relatively Fuel Ratio (FC/VM) - 1.14 1.00 1.21 2.28 1.86 low but Combustibility Index - 2,067 2,353 2,476 2,781 3,492 combustion Carbon % 39.53 31.35 40.24 63.03 62.15 characteristic is good owing to Hydrogen % 2.43 2.30 2.68 3.60 3.87 high volatile Nitrogen % 0.69 0.60 0.83 1.53 1.29 content. Ultimate Oxygen % 6.64 5.35 8.65 7.20 7.80 Analysis Sulfur % 0.45 0.40 0.60 0.72 0.68 Ash % 43.00 45.00 36.00 13.92 14.21 Moisture % 12.00 15.00 11.00 10.00 10.00 Grindability HGI 50 47 52 45 48 Hi – Vol. ‘ C ’ Hi – Vol. ‘ C ’ Hi – Vol. ‘ C ’ Hi – Vol. ‘ C ’ Midium Vol. ASTM Coal Classification - Bituminous Bituminous Bituminous Bituminous Bituminous
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