SuperCritical Boiler-1
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Transcript of SuperCritical Boiler-1
ONCE THROUGH STEAM GENERATORS
Benson boiler growthBenson boiler growth
• 1926 –Siemens maufactures 30–125t/h boilers• 1949 –First OT boiler with high steam conditions(175 bar/610 DegC
– Leverkusen)• 1963 – First spiral tube waterwall in membrane design(Rhodiaceta)• 1987- Largest hard coal fired boiler (Heyden 900 MWMore than 980 boilers with > 700000 t/h
CONTROLLED CIRCULATION (Vs) ONCE THRU’
CC OT
Once Through PrincipleComparison Natural Circulation /
Once-Through-System
Source: Siemens
Cumulative Steam Capacity of Ordered BENSON Boilers
BBP´s share about 44 %
Source: SiemensTotal Steam Output about 200.000 kg/s 220.000 MW
Once Through Boiler-Concept
Once through system
ONCE - THROUGH OPERATING RANGE
Increase of Cycle Efficiency due to Steam Parameters
300241
175 538 / 538
538 / 566
566 / 566
580 / 600
600 / 620
6,77
5,79
3,74
5,74
4,81
2,76
4,26
3,44
1,47
3,37
2,64
0,75
2,42
1,78
00
1
2
3
4
5
6
7
8
9
10
HP / RH outlet temperature [deg. C]Pressure [bar]
Increase of efficiency [%]
Comparison of Plant part load efficiency
30
40
46
30 40 50 60 70 80 90 100Load %
41,1 %
36,7 %
39,3 %40,5 %
43,2 %42,4 %
40,1 %
Pla
nt
net
eff
icie
ncy
Supercritical unitacc. Alternative 2255 bar 538°C / 538°C
Subcritical unitacc. Alternative 1166 bar 538°C / 538°C
43,6 %
Examples of Boiler ConceptsTwo-Pass Boilerwithout platen superheater
Two-Pass Boilerwith platen superheater
Tower Boiler
PS Heyden 4 - 920 MW el PS Kogan Creek - 700 MW elPS Staudinger 5 - 550 MW el
66,0 m
Comparison of Lignite, Coal and Oil Fired Units
PS Offleben (C), 325 MWel PS Farge, 320 MWel PS Doha West, 300 MWel
mHD = 1000 t/h; B = 16,4 m mHD = 1020 t/h; B = 16,5 m mHD = 1100 t/h; B = 14 m
Heat input / furnace area [kW/m²] 215 330 680 SH heating surfaces [m²] 17.781 6.791 10.953 RH heating surfaces [m²] 15.290 12.072 5.202 Bundel surfaces [m²] 33.071 18.863 16.155
Benson BoilerMain Configuration - Single-pass /
Two-pass
Source: Siemens
DRUM vs ONCE THROUGH DRUM vs ONCE THROUGH
Pressure Sub critical Sub & super Critical Steam Separation Drum Separator (Low loads) Types Natural / Assisted (Sulzer) / (Benson)
Burner Panel Straight tube Spiral Tube / Straight (MHI)Load Change Base FasterCold Start 4-5 Hours 2 HoursHot Start 1-2 Hours 0.5 Hours
SH
STEAM TOTURBINE
HEATDOWN
COMER
DRUMECO
Water Wall
ORIFICECIRC. PUMP
SH
STEAM TO TURBINE
ECO
HEAT
Water Wall
Drum type boiler• Steam generation takes place furnace water
walls
• Fixed evaporation end point - the drum
• Steam -water separation takes place in the drum
• Separated water mixed with incoming feed water
Once Through Boiler
• Once -through flow through all sections of boiler (economiser, water walls & superheater)
• Feed pump provides the driving head
• Suitable for sub critical & super critical pressures
Once -thru BoilerAdvantages:• Quick response to load changes• Shorter start up time• Better suited for sliding pressure operation• Steam temperature can be maintained over wider
load range under sliding pressure• Higher tolerance to varying coal quality• Suitable for sub critical & super critical pressures
ADVANTAGES OF ONCE THROUGH BOILERS
Once thru boiler enables :
• Peak power generation with better efficiency levels
• Quicker response to TG load changes
• Better heat rate of lower loads
Once -through BoilerCharacteristics :• Provides Quicker response to TG load changes• Supports achievement of better heat rate at lower
loads• Higher furnace wall pressure drop and consequent
higher feed pump auxiliary power consumption• Needs ultra pure quality feed water - Cannot
operate under conditions of condenser leak
Tower Vs Two passTower Vs Two pass
• For Indian Pit-head power station BBP preference is tower type ( to overcome flyash erosion)
• For power stations firing beneficiated Indian coals – Two pass boiler
• For coastal power stations firing imported coals – Two pass boiler
Flow Scheme of Membrane Walls for Two-Pass Boilers
3.) 1.)
2.)
4.)5.)Detail:Ties for Spiral Tubing
Temperature differencebetween the wall systems(Example Studstrup Power Plant)
Boiler LoadLocation 100% 35%
1.) 2 K 1 K2.) 7 K 1 K3.) 13 K 1 K4.) 2 K 3 K5.) 7 K 17 K
Flow Scheme of Membrane WallsFlow Scheme of Membrane Wallsfor Tower Boilersfor Tower Boilers
Transition from Spiral Tubing to Vertical Tubing
Start-Up Times [min] of Power Plants
Plants with BENSON Boiler250 bar / 540°C / 560°C
Plants with Drum Boiler167 bar / 538°C / 538°C
first steamto Turbine
full load
From ignition to:
first steamto Turbine
full load
From ignition to:
20 - 30
40 - 60
150 - 210
150 - 210
60 - 80
80 - 100
300 - 350
450 - 600
20 - 30
30 - 40
60 - 80
60 - 80
30 - 40
50 - 60
150 - 200
400 - 600
After shutdown hours
<1
8
48
>48
Modern Coal-Fired Power PlantKWU 99 152d
Page 23
EV 2 / ; NTPC Presentation.ppt
BOILERS - DISCUSSED AT BBP
MAJUBA 660 MW TOWER 192 bar 555 C 19286x19286SCHKOPAU 450 MW TOWER 262 bar 545 C 17846x17846VOERDE 700 MW TWO PASS 206 bar 530 C 23668x15773
BOXBERG 900 MW TOWER 266 bar 545 C 24086X24086ELKRAFT 300 MW TWO PASS 250 bar 545 C 12720X14280
MAJUBA,SCHKOPAU,VOERDE : WITH VERTICAL TUBE HOPPER BOXBERG: WITH SPIRAL TUBE HOPPER ELKRAFT: WITH SPIRAL HOPPER & SPIRAL IN FRONT/REAR , HORIZONTAL IN SIDES
Once -thru Boiler - Furnace Wall
Furnace ArrangementFurnace Arrangement
VERTICAL TYPE
SPIRAL TYPE
FURNACE WALL ARRANGEMENT
BOILER PRESSURE PARTS WEIGHT
BOILER TYPE PIPES TUBES
210 MW 315 MT 1100 MT
250 MW 410 MT 1440 MT
500 MW 695 MT 2870 MT
660 MW** 1070 MT 5080 MT
** Worked out based on the Alstom BOM supplied
for SIPAT boiler.
Technology Acquisition Thru Collaboration – Status
•BHEL entered into a TCA with M/S Babcock Borsig Power(BBP), Grmany in 1999.
•First phase of training provided by BPP in 2001.
•BBP has become insolvent in July 2002 & further training planned during the execution of the first contract and technology transfer was not possible.
•Subsequently a new Engg company , Babcock Borsig Power Systems (BBPS), owned by Babcock Hitachi, Japan was formed.
•BBPS was found acceptable for Technical collaboration after “due deligence” exercises. But the collaboration route with BBPS could not be utilised for Sipat tender as NTPC spec required the collaborator to provide financial guarantees.
SIPAT 3x660MW – Joint Bidding with Alstom
•In the original bid submitted in Oct 2003, BHEL-Alstom joint bid was placed at L3, with Dossan/Korea as L1 and TPE/Russia as L2.
•In Dec 2003, NTPC invited snap bids to be submitted by all the three bidders by 9 Jan 2003
•The new requirements (with increased steam flow & for vacating certain deviations) called for a total redesign by Alstom with estimated three months time. Accordingly BHEL sought extension till 05 March 2004 for submitting the revised bid.
•However since the request for extension was not granted by NTPC, the snap bid could not be submitted by BHEL
Immediate OTB projects
•NTPC – BARH 3x660MW
Tender due in May 2004. QR same as Sipat project.
•APGENCO, Vijayawada 1X660MW
Four companies (Alstom, Siemens/Doosan,Sumitomo/Babcock Hitachi & TPE/Russia) have been pre-qualified for EPC