POINTS OF DISCUSSION SUB CRITICAL & SUPER CRITICAL BOILER SIPAT BOILER DESIGN SIPAT TURBINE DESIGN DESIGN PARAMETERS COMMISSIONING PRE COMMISSIONING PROBLEMS POST COMMISSIONING PROBLEM
Descriptionunit S/H STEAM FLOWT/HR SH STEAM PRKG/CM SH STEAM TEMP 0C0C540 RH STEAM FLOWT/HR RH STEAM TEMP INLET 0C0C RH STEAM TEMP OUTLET 0C0C RH STEAM PRESS INLETKG/CM FEED WATER TEMP 0C0C COMPARISION OF 660 MW Vs 500 MW BOILER
Description 660 MW 500 MW Structural Steel Erection Boiler Proper & Accessories (Pre. Parts) Refractory, Insulation & Cladding Power Cycle Piping Soot Blowing System54 76 Coal Firing System Draft System Fuel oil system Miscellaneous System Electrical & Instrumentation TOTAL Tonnage Comparison
Material Comparison Description 660 MW 500 MW Structural SteelAlloy Steel Carbon Steel Water wallT22 Carbon Steel SH CoilT23, T91 T11, T22 RH CoilT91,Super 304 H T22, T91,T11 LTSHT12 T11 EconomizerSA106-C Carbon Steel Welding Joints (Pressure Parts)42,000 Nos 24,000 Nos
Structural Comparison Slno660 MW500 MWRemarks 1STRUCTURALS a Entire structural is bolting type- entire structure is bolted. Holes are drilled on the columns and gusset plates, and supplied with matching plates. Structural is assembled at site with welding Advantages (660MW) of Bolting structure: o Fast in erection. o Clean environment o No Welding network required o Safety at site o Painting finish is good o ( No Weld surface) b. No Welding work involved in assembly/ Erection, except Walkway rail post welding Assembly is carried out with Welding Can be dismantled if required ( For Maintenance purpose) c Material supply is tier wise including staircases, railing, gratings etc. Material is supplied as per the erection sequence. Erection completion tier wise, including gratings, platforms, staircases etc.
1Cost of SG Package Cr Cr with ESP 2Cost of ESP183.54Cr 3Total cost of Boiler + ESP Cr Cr 4 Cost of Boiler per MW with ESP 1.09 Cr1.02 Cr 5Cost of TG for entire stage Cr Cr 6TG cost per MW 0.6Cr0.63 Cr COST COMPARISON
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. UNDERSTANDING SUPER CRITICAL TECHNOLOGY
HPT IPT LPT CONDENSERCONDENSER FEED WATER FRS STORAGE TANKSTORAGE TANK SEPARATOR BWRP Spiral water walls MS LINE HRH LINE VERTICAL WW ECO I/L ECO JUNCTION HDR ECO HGR O/L HDR FUR LOWER HDR FUR ROOF I/L HDR DIV PANELS SH PLATEN SH FINAL RH FINAL SH LTRH ECONOMISER 290°C, 302 KSC 411°C, 277Ksc 411°C, 275 Ksc 492°C, 260 Ksc 540°C, 255 Ksc 305°C, 49 Ksc 457°C, 49 Ksc 568°C, 47 Ksc G LPT
Boiling process in Tubular Geometries Heat Input Water Steam Partial Steam Generation Complete or Once-through Generation
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 FD FAN2 No’S ( AXIAL )11 kv / 1950 KW228 mmwc 1732 T / Hr PA FAN2 No’s ( AXIAL)11 KV / 3920 KW884 mmwc 947 T / Hr ID FAN2 No’s ( AXIAL)11 KV / 5820 KW3020 T / Hr TOTAL AIR2535 T / Hr SH OUT LET PRESSURE / TEMPERATURE / FLOW 256 Ksc / 540 C 2225 T / Hr RH OUTLET PRESSURE/ TEMPERATURE / FLOW 46 Ksc / 568 C 1742 T / Hr SEPARATOR OUT LET PRESSURE/ TEMPERATURE 277 Ksc / 412 C ECONOMISER INLET304 Ksc / 270 C MILL OPERATION7 / 10 COAL REQUIREMENT471 T / Hr SH / RH SPRAY89 / 0.0 T / Hr BOILER EFFICIENCY87 %
1.High erosion potential for pulverizer and backpass tube is expected due to high ash content. 2. Combustibility Index is relatively low but combustion characteristic is good owing to high volatile content. Coal Analysis
1.Lower slagging potential is expected due to low ash fusion temp. and low basic / acid ratio. 2. Lower fouling potential is expected due to low Na2O and CaO content. Ash Analysis
Constant Pressure Control Above 90% TMCR The MS Pressure remains constant at rated pressure The Load is controlled by throttling the steam flow Below 30% TMCR the MS Pressure remains constant at minimum Pressure Sliding Pressure Control Boiler Operate at Sliding pressure between 30% and 90% TMCR The Steam Pressure And Flow rate is controlled by the load directly BOILER LOAD CONDITION
Benefits Of Sliding Pressure Operation ( S.P.O) Able to maintain constant first stage turbine temperature Reducing the thermal stresses on the component : Low Maintenance & Higher Availability No additional pressure loss between boiler and turbine. low Boiler Pr. at low loads. WHY NOT S.P.O. IN NATURAL/CONTROL CIRCULATION BOILERS Circulation Problem : instabilities in circulation system due to steam formation in down comers. Drum Level Control : water surface in drum disturbed. Drum : (most critical thick walled component) under highest thermal stresses
LMZ (LENINGRADSKY METALLICHESKY ZAVOD) K STANDS FOR KLAPAN LTD.,BULGARIA WHICH SUPPLIES TURBINE,NOZZLES,DIAPHRAGMS, SEALS,BLADES ETC.
1.TG DECK IS VIS SUPPORTED AND HAS 26 CONCRETE COLUMNS (T1 – T26). 2.TG HALL IS CONSTITUTED OF 3 MAINS ROWS OF COLUMNS – A,B,C ROW AND TWO BAYS – AB BAY AND BC BAY. THE WIDTH OF AB BAY IS 36m AND BC BAY IS 12m 3.CONDENSER TUBE BANKS (CW PATH) HAS AN INCLINATION OF THERE ARE TWO MAIN EOT CRANES FOR TG HALL.EACH EOT CRANE IS HAVING A CAPACITY OF 200t FOR MAIN HOIST AND 20t FOR AUXILIARY HOIST. 35.5m IS THE MAXIMUM VERTCAL DISTANCE A HOIST CAN TRAVEL.TANDEM OPERATION OF TWO EOT CRANES ARE ALLOWED.
Ext. No Source Of ExtractionDestination Equipments 113th stage of HPTHPH-8 2CRHHPH-7 33rd stage of IPTHPH-6 * 33rd stage of IPTTDBFP 46th stage of IPTDEAERATOR 58th stage of IPTLPH-4 611th stage of IPTLPH-3 72nd stage of LPTLPH-2 84th stage of LPTLPH-1
Condenser DesignLMZ Design CW Flow64000 m 3 /hr Vacuum 77 mm Hg (abs) at 33 0 C 89 mm Hg (abs) at 36 0 C No. of passes1 Total no. of tubes (OD)x0.71 (t) (OD)x1.00 (t) Tube materialASTM A-249 TP 304 Rated TTD3.4 0 C DT of CW10 0 C
Condensate Extraction Pump Design flow rate Kg/s Discharge pressure32.15 Ksc Shut off head395 m Pump speed 1480 rpm Power input972.3 KW No. of stages6 Type of first stage impellerdouble entry Depth7.43 m
MDBFP Pump flow TPH Suction temp C BP Suction pr.14.05ata BFP Suction pr.21.01ata BFP Discharge pr ata BFP Discharge temp C BP Discharge pr.22.01ata Shut off head4830m BFP Speed6275 rpm BP Speed1490rpm Normal R/C flow220TPH HC Rated O/P Speed6505rpm Outer casing typebarrel No. of stages7 BFP warm up flow15TPH
TDBFP Pump flow TPH Suction temp186.20C BP Suction pr.14.10ata BFP Suction pr.28.24ata BFP Discharge pr ata BFP Discharge temp C BP Discharge pr.29.06ata Shut off head4580m BFP Speed4678 rpm BP Speed2098rpm Normal R/C flow365TPH HC Rated O/P Speed6505rpm Outer casing typebarrel No. of stages7 BFP warm up flow20TPH
Drip Pump Design flow rate TPH Discharge pressure43 ata Shut off head306.7m Pump speed1486rpm Power input310.1KW No. of stages5 Type of first stage impellercentrifugal, single entry Depth1090 mm
RATED CONDITIONS LOAD :660MW BEFORE HP STOP VALVE STEAM PRESSURE:247KSC STEAM TEMPERATURE:537 0 C STEAM FLOW: T/HR AFTER HPC STEAM PRESSURE:48KSC STEAM PRESSURE: C BEFORE IP STOP VALVE STEAM PRESSURE:43.2KSC STEAM TEMPERATURE:565 0 C STEAM FLOW TO REHEATER: T/HR. DESIGN CONDENSER PRESSURE:0.105KSC (abs.) COOLING WATER FLOW:64000M 3 /HR FINAL FEED WATER TEMP.: C FREQUENCY RANGE:47.5 – 51.5 Hz
STEAM TURBINE Generator rated speed3000rpm Generator manufacturerElectrosila No. of bleedings8 Length of the turbine36.362m No. of stages HPT17 IPT11x2 LPT-15x2 LPT-25x2 Total59 Turbine Governing system Mode of Governing Nozzle TypeE/H Control fluidFirequel-L make Supresta-USA Normal Operating Pr.50 Ksc Capacity600 lpm Fluid pump motor rating200 KW Filter materialUltipor Mesh size25 µ
Turbine Protections Turbine protection system consists of Two Independent channels, each operating the corresponding solenoid (220V DC) to trip the Turbine in case of actuation of remote protection Hydraulic Protection: Apart from the Electrical Trip, Turbine is equipped with the following Hydraulic Protections: 1. Local Manual Trip (1V2) 2. Over speed Trip #1 at 110% of rated speed 3. Over speed Trip #2 at 111% of rated speed 4. Governing oil pressure < 20 Ksc Contd..
5.Axial shift Very High (2V3) [-1.7mm, +1.2mm] 6.Turbine bearing vibration : Very High (2V10 including X & Y directions)* >11.2mm/sec (Td=2 sec) 7.Lube oil tank level very Low (2V3)* Td=3sec (Arming with two stop valves open) 8.Lub oil pressure Very Low (2V3) < 0.3 Ksc; Td =3 sec (Arming with two stop valves open) 9.Condenser pressure Very High (2V3) > - 0.7ksc (Arming with condenser press < 0.15 ksc Abs) Contd
10.M.S. temp Very Low (2V3) 512 deg C)* 11.M.S. temp Very High (2V3) > 565 deg C* 12.HRH temp Very Low (2V3) 535 deg C)* 13.HRH temp Very High (2V3) > 593deg C* 14.HPT outlet temperature Very High (2V4) > 420 deg C Contd…
15.Gen seal oil level of any seal oil tank Very Low (2V3)* < 0 mm;Td=15 sec (Arming with any two stop valves open) 16.All Generator seal oil pumps OFF (3V3)* Td: 9 sec (Arming with any two stop valves open) 17.Generator Stator winding flow Very Low (2v3) < 17.3 m3/hr; Td =120 sec (Arming with any two stop valves open) 18.Generator hot gas coolers flow Very LOW (2V3)* : <180m3/hr; Td=300sec(Arming with any two stop valves open) 19.Generator cooler hot gas temp. Very High(2V4) > 85 deg (Td = 300sec Contd
OF SIPAT SUPER CRITICAL UNIT 1 ST UNIT SYNCHRONIZED AT : ST UNIT FULL LOAD ACHIEVED AT : 2 nd UNIT SYNCHRONIZED AT : ND UNIT FULL LOAD ACHIEVED AT :
PRE – COMMISSIONING ACTIVITIES CHEMICAL CLEANING OF BOILER : CHEMICAL CLEANING OF BOILER REQUIRED FOR Maintaining steam quality at the turbine inlet. Minimizing corrosion of the metal surface of boiler. DETERGENT FLUSHING OF PRE-BOILER SYSTEM To remove dirt,oil,grease etc., from Condensate,Feed water, Drip and Extraction steam lines of HP and LP heaters prior to putting these systems in regular service. This is to ensure flow of clean condensate and feed water to the boiler. STEAM BLOWING OF POWER CYCLE PIPING :STEAM BLOWING OF POWER CYCLE PIPING 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. SAFETY VALVE FLOATING
PRE – COMMISSIONING CHECKS All commissioning procedure should be finalized. P&I Drawings should be finalized and available with site engineer Different systems check list should be finalized with all concerned agencies All Field quality checks should be completed. P&I Checks should be finalized. Start – Up procedure should be finalized
COMMISSIONING SEQUENCE OF TG SIDE 1.Commissioning of stator water cooling system for HV testing before generator rotor insertion. a)Stator water pump trial run. b)Flushing of the system bypassing winding. c)Flushing of the system through the winding. 2.Commissioning of MCW,ACW and DMCW system. a)Trial run of pumps. b)Flushing of the system. 3.Detergent Flushing of pre boiler system (Feed water,condensate,HPH and LPH drip system) a)Cold water flushing until turbidity comes below 5NTU. b)Hot water flushing (60 0 C) with 2 hrs circulation of each circuit. c)Raising water temperature to 60 0 C and addition of Detergent d)(Coronil 100%)
e) Circulation through each circuit for 2 hrs. f) Hot draining of the system g) DM water rinsing of each circuit until conductivity comes below 5µs/cm and oil content BDL. h) Passivation with ammonia and hydrogen peroxide solution at a temperature of 40 0 C. i)Draining of the system. 4. Lube oil flushing of MDBFP lube oil system. 5.Trial run of MDBFP. 6.Lube oil and seal oil flushing of main TG. 7.CF system flushing. 8.Condenser flood test. 9.Trial run of CEPs 10.Commissioning of generator gas system. 11.Generator ATT. 12.Calibration of HPCVs and IPCVs 13.Putting turbine on barring. 14.Vacuum pumps trial run.
15.Commissioning of seal steam system. 16.Commissioning of HP and LPBP system. 17. Vacuum pulling. 18.Lube oil flushing of TDBFP. 19.Steam blowing of TDBFP steam line. 20.Commissioning of TDBFP.
FUR DRAFT SYSTEM SEC AIR SYSTEM TG ON BARRING BRP TRIAL RUN TG LUBE OIL / GEN SEAL OIL SYSTEM FURNACE READINESS FUEL OIL SYSTEM READINESS DDCMIS FSSS READINESS MFT CHECKING GATES, DAMPERS / VALVES TG : SG : (13 / 190 ) STATOR COOLING WATER CW SYSTEM READINESS CHEMICAL CLEANING OF BOILER MS Line Welding Completion ( 30 Pen) CRH Line Welding Completion ( 12 Pen) HRH Line Welding Completion (34 Pen) MS Line Hanger Erection Cold Setting CRH Line hangers Cold Setting HRH Line Hangers Cold Setting MS Line Insulation CRH Line InsulationHRH Line Insulation MS Line HT CRH Line HTHRH Line HT COMPRESSED AIR SYSTEM READINESS AUX PRDS READINESS CONDENSER VACCUM SYSTEM POWER CYCLE PIPING STEAM BLOWING UNIT SYNCHRONIZTION MDBFP Trial CEP Trial TG SEAL STEAM SYSTEM TG CONTROL FLUID SYS TG GOV SYSTEM GEN GAS SYSTEM
Questions Please Enlighten Us Discussion
Evaporator – heat absorption
Reduced number of evaporator wall tubes. Ensures minimum water wall flow.
SPIRAL WALL ARRAMGEMENT AT BURNER BLOCK AREA :
Support System for Evaporator Wall Spiral wall Horizontal and vertical buck stay with tension strip Vertical wall Horizontal buck stay