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Enhancing Capacity – Empowering Nation
Presentation on Supercritical Boilers 28 August 2012
SupercriticalUltra Supercritical
&Advanced Ultra Supercritical
Steam Generators
New trends in Boiler Technology
SupercriticalUltra Supercritical
&Advanced Ultra Supercritical
Steam Generators
New trends in Boiler Technology
M. AnandarajDeputy General Manager
BHEL, Tiruchirappalli
Enhancing Capacity – Empowering Nation
Presentation on Supercritical Boilers 28 August 2012
Presentation on Supercritical Boilers 28 August 2012
Unit Contracted Commissioned
VU 40 46 45
VU 40 S 15 15
VU 60 38 19
MU 3 3
VP 23 16
V2R 17 17
HRSG 177 121
AFBC 72 59
CFBC 28 10
Others 28 28
Total 447 333
BHEL Industrial Units - A Summary
Enhancing Capacity – Empowering Nation
Presentation on Supercritical Boilers 28 August 2012
BHEL is currently adopting
Advanced Steam Cycles to Improve the Environmental & Economic Performance of
India’s Power Generation
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Presentation on Supercritical Boilers 28 August 2012
Reference List of Supercritical Boilers
NTPC / BARH 2 x 660MW
APPDCL / Krishnapatnam 2 x 800 MW
PPGCL / BARA 3 x 660 MW
RPCL / Yermaras 2 x 800 MW
RPCL / Edlapur 1 x 800 MW
KPCL / Bellary 1 x 700 MW
LPGCL/Lalithpur- BHL 3 x 660 MW
DB Power / Singrauli 2 x 660 MW
NTPC / Mouda St. II 2 x 660 MW 18 Boilers Contracted
Enhancing Capacity – Empowering Nation
Presentation on Supercritical Boilers 28 August 2012
Emerging Market Requirements For Thermal Power Generation
High Reliability & Availability Highest Plant efficiency Suitable for differing modes of operation Suitable for varying fuel quality Minimum emission of Pollutants Lowest cost
Enhancing Capacity – Empowering Nation
Presentation on Supercritical Boilers 28 August 2012
Higher Plant efficiency for
• Conservation of fuel resources• Reduction of Atmospheric Pollutants - CO2 , SOX & NOX
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Presentation on Supercritical Boilers 28 August 2012
Measures to improve Plant Efficiency
Cycle Parameters :• Higher steam parameters with Once Thro’ Boilers
Boiler side measures :• Highest Boiler Efficiency• Minimum RH spray• Minimum SH spray (if tapped off before feed heaters)• Reduced auxiliary power consumption
Enhancing Capacity – Empowering Nation
Presentation on Supercritical Boilers 28 August 2012
Increase of Plant Cycle Efficiency due toSteam 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 [%]
Enhancing Capacity – Empowering Nation
Presentation on Supercritical Boilers 28 August 2012
500 MW Steam GeneratorCoal Consumption and Emissions
Subcritical Unit
Supercritical Unit
Coal Saving t/year Base 68800
CO2 Reduction t/year Base 88270
SO2 Reduction t/year Base 385
Basis:
Cycle Efficiency
%
Base
+1.0
No. of operating hrs.
Hrs./year 8000 8000
Enhancing Capacity – Empowering Nation
Presentation on Supercritical Boilers 28 August 2012
Current Trends in Steam Parameters
• 1980s : Pressure increased from 175-180 bar to 225 bar;
Temperature mostly around 540 °C
• 1990 : Pressures raised to 285 bar;
Temperature raised to 565-580-600 °C
• 300 bar & 620 °C not unusual today
• 255 bar & 568/596 °C commonly used presently
Enhancing Capacity – Empowering Nation
Presentation on Supercritical Boilers 28 August 2012
• Coal will continue to have maximum share towards installed capacity for electricity at least upto 2050
• CLEAN COAL TECHNOLOGY– Minimise CO2 emissions and environmental impact – Extend life of coal reserves
• Approach: Develop technology for SC, USC & Adv-USC power plants
14
# The improvements are with respect to the best units under construction in India
• Extension of coal reserves by 11%
• Competitive in electricity cost on deployment
Efficiency and CO2 Emission
Plant type with power rating
Steam Pressure (kg/cm2)
Steam Temperature
(C)
Efficiency (%)
CO2 Emissions (g/kW-hr)
Sub Critical (500 MWe)
170 540 35 900
# Super Critical 247 565 40 830
Ultra Super Critical 250 600 42 784
Advanced Ultra Super Critical
300 700 45 740
Enhancing Capacity – Empowering Nation
Presentation on Supercritical Boilers 28 August 2012
Trend in unit sizes & Cycle parameters
Unit SizeSHO Pressure
(kg/cm2(a))
SHO/RHO Temperature
(Deg.C)
Year of Introduction
60 / 70 MW 96 540 1965
110 / 120 MW 139 540/540 1966
200 / 210 MW 137 / 156 540/540 1972
250 MW 156 540/540 1991
500 MW 179179
540/540 540/568
19791985
660 MW 256 568/596 2008
800 MW 256 568/596 2008
Enhancing Capacity – Empowering Nation
Presentation on Supercritical Boilers 28 August 2012
Type of boilers
Drum type
- for sub-critical parameters
Once-through type - for sub/super Critical Parameters
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Presentation on Supercritical Boilers 28 August 2012
Drum type boiler
Steam generation takes place in furnace water walls Fixed evaporation end point - the drum Steam -water separation takes place in the drum Separated water mixed with incoming feed water
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Presentation on Supercritical Boilers 28 August 2012
Types of Circulation
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Presentation on Supercritical Boilers 28 August 2012
Drum type boiler
Natural Circulation Boiler
Circulation thru water walls by thermo-siphon effect
Controlled Circulation Boiler
At higher operating pressures just below critical pressure levels, thermo-siphon effect supplemented by pumps
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Presentation on Supercritical Boilers 28 August 2012
Natural Circulation Controlled Circulation
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Presentation on Supercritical Boilers 28 August 2012
Pressure range
Sub critical : Below 221 bar
Super critical : 221 bar and above
What is Super critical pressure ?
Enhancing Capacity – Empowering Nation
Presentation on Supercritical Boilers 28 August 2012
SC Steam generator
Boiler Steam Pressure above the critical point Critical Point
221 bar, 374 º c
S
T
1
2
3
4
Entropy
Tem
per
atu
re
1 - 2 Feed Water Pumping Process 2 - 3 Heat addition in the Feed
Water Heaters & Boiler 3 - 4 Expansion in HP Turbine 4 - 5 Reheating in Boiler 5 - 6 Expansion in IP & LP Turbine 6 - 1 Heat rejection in Condenser
5
6
Enhancing Capacity – Empowering Nation
Presentation on Supercritical Boilers 28 August 2012
Supercritical Boilers
Supercritical pressure boiler has no drum and heat absorbing
surface being, in effect, one continuous tube, in which the water &
steam generated in the furnace water walls passes through only
once hence called ‘Once through Supercritical pressure boilers’
The water in boiler is pressurized by Boiler Feed Pump, sensible
heat is added in feed heaters, economizer and furnace tubes, until
water attains saturation temperature and flashes instantaneously
to dry saturated steam and super heating commences.
Enhancing Capacity – Empowering Nation
Presentation on Supercritical Boilers 28 August 2012
The Concept
The mass flow rate thru’ all heat transfer circuits from Eco. inlet to
SH outlet is kept same except at low loads wherein recirculation is
resorted to protect the water wall system
Enhancing Capacity – Empowering Nation
Presentation on Supercritical Boilers 28 August 2012
Increased mass flow through spiral waterwall tubing, or improved heat transfer through rifled vertical wall tubing.
No fixed evaporator end point
No thick wall components
Features
Once Through Boiler Flow Diagram
Evaporator
Water separator
Feedwater
Economizer
FW-Pump
Live steam
Superheater
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Presentation on Supercritical Boilers 28 August 2012
Supercritical Boilers- Major Systems
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Presentation on Supercritical Boilers 28 August 2012
General Arrangement of Steam Generator – Elevation
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Presentation on Supercritical Boilers 28 August 2012
General Arrangement of Steam Generator – Plan
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Presentation on Supercritical Boilers 28 August 2012
Once through Supercritical Boilers
Major differences from Drum type boiler :
Evaporator system
Low load Recirculation system
Separator
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Presentation on Supercritical Boilers 28 August 2012
STEAM TO TURBINESTEAM TO TURBINE
SHSH
DRUM
SEPERATINGVESSEL
EVA
POR
ATO
R
EVA
POR
ATO
R
ECO.
ECO.
(LOW LOAD &CIRCULATION PUMP
START-UP)
FEED
FEED
CIRCULATION TYPEASSISTED
Circulation Systems
Drum Type Once-through
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Presentation on Supercritical Boilers 28 August 2012
Once -through Operating Range
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Presentation on Supercritical Boilers 28 August 2012
Once -thru Boiler
Requirements :
Stringent water quality
Different control system compared to drum type
Low load circulation system
Special design to support the spiral furnace wall weight
High pressure drop in pressure parts
Higher design pressure for components from feed pump to separator
Enhancing Capacity – Empowering Nation
Presentation on Supercritical Boilers 28 August 2012
Features of Once Through Steam Generator
To ensure adequate mass flow rates through water wall, spirally wound water wall tubes are used.
Start-up and low load system up to 30-40% BMCR required.
Feed water quality requirements are very stringent.
Can be designed for both sub-critical and super-critical pressures.
Ideally suited for sliding pressure operation due to the absence of thick walled components.
Enhancing Capacity – Empowering Nation
Presentation on Supercritical Boilers 28 August 2012
Once -thru Boiler
Evaporator system :
Formed by a number of parallel tubes
Tubes spirally wound around the furnace to reduce number of tubes and to increase the mass flow rate thru’ the tubes
Small tube diameter
Arrangement ensures high mass velocity thru the tubes
Enhancing Capacity – Empowering Nation
Presentation on Supercritical Boilers 28 August 2012
· Reduced number of tubes with pitch.
· Increased mass flow.
· Mass flow rate can be selected by number of tubes.
Features
Spiral Tube Arrangement
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Presentation on Supercritical Boilers 28 August 2012
Once -thru Boiler - Furnace Wall
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Presentation on Supercritical Boilers 28 August 2012
Spiral Water wall Tubing
Lateral Heat Flux Profile
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Presentation on Supercritical Boilers 28 August 2012
Sliding Pressure Supercritical Design
Spiral Wall Windbox
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Presentation on Supercritical Boilers 28 August 2012
SPIRAL WALL SUPPORT
Support Fingers
Spiral to Vertical Transition Area - Load Transfer
Sliding Pressure Supercritical Design
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Presentation on Supercritical Boilers 28 August 2012
Presentation on Supercritical Boilers 28 August 2012
General Arrangement of Steam Generator – Plan
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Presentation on Supercritical Boilers 28 August 2012
ULTRA SUPER CRITICAL TECHNOLOGY&
ADVANCED ULTRA SUPER CRITICAL TECHNOLOGY
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Presentation on Supercritical Boilers 28 August 2012
The Basic Heat Cycle
Sub-critical units: Main steam pressure < 221. 1 barSuper-critical units: Main steam pressure > 221. 1 bar
Ultra-supercritical units:Higher steam pressure and temperature than supercritical units
Japan: Main steam pressure >242 Bar, or Steam temperature >593 ℃
Demark: Main steam pressure >275 BarChina: Main steam pressure >270 BarUSA (EPRI) : Main steam temperature>593 ℃
Enhancing Capacity – Empowering Nation
Presentation on Supercritical Boilers 28 August 2012
• Plant with steam pressure exceeding 225 kg/cm2 is said “Supercritical”
• Supercritical plant with main steam temperature 600C is said “Ultra Super-Critical”
• Supercritical plant with main steam temperature 700C is “Advanced Ultra Super-Critical
STEAM PARAMETERS
Enhancing Capacity – Empowering Nation
Presentation on Supercritical Boilers 28 August 2012
Evolution of Steam Power Stations Efficiency Worldwide
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Presentation on Supercritical Boilers 28 August 2012
64ADVANCED USC TECHNOLOGY28 August 2012
EUROPEAN PERSPECTIVE AND ADVANCEMENT FOR ADVANCED USC
Pulverised Fuel-importance in World Power Generation
Background of Development Of USC Plant with Steam Temperature around 600 0C
Immediate Possibility of going to 650 0C & 700 0C with Nickel Alloy
Best Strategy for reduction of CO2 Emission
Enhancing Capacity – Empowering Nation
Presentation on Supercritical Boilers 28 August 2012
66ADVANCED USC TECHNOLOGY28 August 2012
AD700 TECHNOLOGY
USC steam parameters-700 0C and 350 bar
This can be achieved only by using Nickel based alloys
In July 2005 :COMTES 700 testing most important components – started operation in power plant Scholven in Gelchen-kirchen
Completed in 2009. During operation phase, valuable operational experience and processing technical knowledge were gained
Welding of thick walled materials must be improved
More test needed for improved welding techniques for 617 or Alloy 740 or Nimonic 263
67ADVANCED USC TECHNOLOGY28 August 2012
Japanese programme 2007 & 2008 (finding out and stabilising the structure parameters affecting creep strength and degradation for accurately estimating 1,00,000 hr creep strength)
New alloys
Fundamental studies on creep strength degradation assessment needed to ensure long term safe use.(FS->650 0C AS ->700 0C Ni-> 750 0C)
FS->100 MPa @ 650 0C beyond 30000 hrs without any type IV degradation
AS->generated by means of inter metallic compound precipitation strength grain boundary, strongest creep.
R&D PROGRAM FOR A-USC MATERIAL DEVELOPMENT WITH CREEP STRENGTH/DEGRADATION ASSESMENT STUDIES
68ADVANCED USC TECHNOLOGY28 August 2012
USC POWER PLANT DEVELOPMENT IN JAPAN
69ADVANCED USC TECHNOLOGY28 August 2012
METI/NEDO MATERIAL R&D PROGRAM
70ADVANCED USC TECHNOLOGY28 August 2012
China first established use with parameters 600 0C/25 MPa in 2006
TP347FGH & Super304H
GH984, Nimonic 80A
Ni-Cr-Co Inconel 740 studied with Special Metal Corp. USA for steam temperature of 700 0C
STRUCTURAL STABILITY STUDY ON USE POWER PLANT ADVANCE HEAT RESISTANCE STEELS AND ALLOYS IN CHINA
71ADVANCED USC TECHNOLOGY28 August 2012
A cost effective CO2 emission reduction option
Engineering design study(EPRI)
Cost and performance of USC with conventional coal power plants
Slightly more expensive
Cost of avoided CO2 emission was less than $25 per metric ton of CO2 capture and storage
ECONOMIC ANALYSIS (EPRI)
72ADVANCED USC TECHNOLOGY28 August 2012
• STEAM SIDE OXIDATION
• FIRE SIDE CORROSION
• CREEP STRENTH
MATERIAL SELECTION
73ADVANCED USC TECHNOLOGY28 August 2012
GKM TEST RIG
74ADVANCED USC TECHNOLOGY28 August 2012
GKM TEST RIG
75ADVANCED USC TECHNOLOGY28 August 2012
Strengthening and degradation of long term creep properties and the relevant microstructural evolution in advance high Cr-Ferritic steels and Austenitic steels at high temperature
GKM TEST RIG
Investigation of the long term operation behaviour tubes and forgings made of alloys for future high nuclear power plants
Qualification of key materials for 700°C fossil fuel power plant
Demonstration of material performance with special consideration of oxidation and corrosion behaviour
Creep damage development
Early detection of damage in new material in connection with advance calculation tools for components
ADVANCES IN MATERIAL TECHNOLOGY
76ADVANCED USC TECHNOLOGY28 August 2012
ADVANCE CONCEPT FOR MAINTANENCE AND REPAIR FOR COMPONENTS MADE OF NEW MATERIALS
SH Test Track
Creep Test Track (upto 630 °C Austenite steel & upto 725 °C Ni based alloys)
Monitoring devices for evolution of ongoing damage
ADVANCES IN MATERIAL TECHNOLOGY
77ADVANCED USC TECHNOLOGY28 August 2012
BY SPECIAL METALS CORPORATION
Developed for operating with 700°C steam temperature and higher pressure.
EUROPEAN TARGET
Stress rupture requirement of 1,00,000 Hrs rupture life at 750°C and 100 MPa stress.
Metal loss of less than 2 mm in 2,00,000 hrs of Superheater service.