3rd Oxyfuel Combustion Conference Workshop 2: Development in Oxy-FBC Combustion
E.J. Anthony, School of Applied Sciences
Current State of Development in Oxy-CFB Technology for Coal-Fired Power Plants
What is changing and why? FBC is an established
technology, with a solid penetration of the utility market
However, in the past such units have been relatively small (<300 MWe)
Concerns over GHG are encouraging: supercritical designs, oxy-fired designs and dual fluidized bed designs, this is a remarkable period of change only partially stifled by economic conditions!
Advanced Supercritical CFB Design produced by Foster Wheeler
CFBC are getting bigger! – CFB800 Scale up CFB technology to 600-800 MWe, with efficiency of 45%
http://www.vtt.fi/files/sites/flexiburncfb/cfb800_brochure.pdf
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The first CFB boiler using OTU Benson Low Mass Flux technology
The first CFB boiler with supecritical steam parameters
The largest CFB boiler in the world Wide base fuel range, opportunity fuel
utilization combined with high efficiency factor of the plant
Design supporting alternate, more efficient, reliable operation
Low SOx & NOx emissions utility scale solution without wet FGD
Flue Gas Heat Recovery applied to CFB allowing to use cooling tower as stack
The Lagisza Project – 460 MWe Foster Wheeler Advancing Steam Plant Technology
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Poludniowy Koncern Energetyczny (PKE) Lagisza Power Plant, Bedzin, Poland – Foster Wheeler
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Customer: Energomachinostroitelny Alliance (EMA), Russian power machine building company
330 MWe Supercritical CFB power plant located in Novocherkasskaya, in Southern Russia (Rostov region)
Contract awarded December 21, 2007
Foster Wheeler delivery • Design, materials, and equipment for
boiler island – CFB technology
• Auxiliary equipment
330 MWe Foster Wheeler Supercritical CFB
The First CFB Power Plant in Russia
Samcheok Green Power Project
The Korean Southern Power Company plans to install eight 550 MWe FW Supercritical FBC Boilers
Future of Fossil Fuel Thermal Power
Some utilities will resist replacement of boilers with gas fired units because of concerns about price volatility
Average age of Canadian power plant is ~30 years, with life extension power plant cannot be maintained much beyond 50 years
Thus, the majority of Canadian thermal power plants must be replaced within ~ 20 years, a similar if more challenging situation exists for the United States and many other places in the world
EON Overview of Technologies demonstrating volatility of natural gas prices
Possible Solutions Replacement technologies not employing natural
gas must be in an advanced state of development if they are to be deployed within 20 years, which limits technologies to: Supercritical boilers (PC and CFBC) Oxyfuel technologies (PC and CFBC) Backend technologies (amines, chilled NH3, Ca
looping) Gasification (with or without shift reactors)
Other alternatives to natural gas are advanced super-critical CFBC firing high quantities (>50%) of biomass to achieve overall CO2 emissions equivalent to firing natural gas and dual fluidized bed gasifiers
The future of natural gas
If hydraulic fracturing and unconventional natural gas are available in large quantities most coal plants in the US will close!
Cheap high quality coal will then be available in Europe and elsewhere so its use depends on legislation rather than economic drivers and public acceptance of CCS
It is an assumption that cheap natural gas will be available for the next 20-30 years:
US Economy - Is The US Shale Boom Already Over? By: The Energy Report | Date: 10 May 2013
http://www.economywatch.com/economy-business-and-finance-news/is-the-us-shale-boom-already-over.10-05.html
Reasons for Oxy-fired CFBC
General advantages of CFB : Fuel Flexibility Increasing importance as availability of premium fuels diminishes!
Low emissions In-situ SOx removal, low NOx, low VOC, PAH etc.
Particular advantages Oxyfuel CFB : Thermal flywheel of solid particles offers: Efficient temperature control Capability for heat extraction, external to furnace Potential for high [O2], and low flue gas recycle offers more
compact units, a major advantage for FBC designs It is fairly easy to make oxy-fuel pilot plants that work!
Cuiden Oxy-fired CFBC Boiler
This unit uses Foster Wheeler’s Flexi-burn® Technology
Steam turbine
Flue gas recycle
Boiler Compression Purification
Flue gas cleaning
CO2
Air Air separation
N2, (Ar)
G
Coal
CO2/H2O
H2O
Condensation
Transport Storage
Vent gas 95-99+% O2,
(Ar, N2)
Pipeline transport in supercritical phase, p>74 bar (high density, low viscosity)
•Flue gas recycle to assist in temperature control; can be
reduced by adding in-furnace or FB HEX
•Purity of oxygen is a process optimization issue
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Flexi-Burn® Combustion – Foster Wheeler
• At high O2 concentrations the generated heat per volume is substantially higher than in combustion with air
• Adiabatic combustion temperature rises
• Changes in hydrodynamics
• Materials in the high CO2 and H2O gas atmosphere
• Emissions prediction
• Elimination of air in-leakage
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normal air combustion
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Flexi-Burn® CFB Technology Challenges – Foster Wheeler
Flexi-Burn® CFB is considered technically viable. Accurate design and performance prediction are challenging, especially at high O2 (optimized design) → Needs for
• Experiments in bench scale and pilot test facilities • Development and validation of design models
• Long-term demonstration runs
Surface Location and Reheat Control Options – FW- 800 MWe Boiler
Foster Wheeler’s INTREX
The Integrated Recycle Heat Exchanger is a key part of Foster Wheeler’s technology and appears to be fully compatible with oxy-fuel FBC
CanmetENERGY 0.8 MWth Oxy-Fuel CFB Combustion Pilot Facility Design parameters:
Furnace: Ø 16” x 21.6 ft
Refractory lined furnace, cyclone and return loop
Four bayonet cooling tubes for furnace temperature control (adjustable on-line)
Fuel and limestone feeding systems
Recycle gas cooler, fan and oxygen mixer for oxidant preparation in oxy combustion
Oxygen storage tank with a vaporizer and instrumentation
Analyzers for continuous measurement of CO2, CO, O2, SO2, and NOx
Data acquisition system
Mini-CFB Operational Experience
Transition from air-fired to oxy-fired is smooth and rapid:
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Transition from Air Firing to Oxy-fuel Firing in CanmetENERGY’s Mini-CFBC during 2nd Highvale Coal Test
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First successful oxy-fuel test on the 0.8MWth unit. Fuel is Pine Bend coke. Note the transition from air firing to oxy-fuel mode in about 30 min.
5 MW CFB pilot tests Aims: To investigate Difference between air and oxy-combustion Safe operation of oxyfuel combustion (process control, interlocking
system) Different test parameters
Introduction Modeling Experiment
Specifications: h= 13 m, Atop= 1x1 m2
52 tests in 4 weeks
Varonen, Metso Power Oy
Solid circulation as a key parameter
Introduction Modeling Experiment
Air-fired
O2 [%mass]
Hea
t ext
ract
ion
norm
aliz
ed b
y to
tal t
herm
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ower
Crucial design parameter for oxyfuel CFB
Oxyfuel case - gas concentration
Experimental values which are shown here, are cross sectional averages (from three lateral positions). Model values are cross sectional averages.
Introduction Modeling Experiment
Comprehensive model of CFB combustion – Chalmers University
Heat transfer
Modeling
Combustion
Char combustion
Volatile combustion
Disperse phase Dense bed
Cluster phase
Convection
Radiation
Fluid dynamics Sorbent
Behaviour
Fludized bed boiler structure and Oxycombustion
SOLID RECIRCULATION and EXTERNAL HEAT EXCHANGER
GAS\SOLID SEPARATOR
(cyclone) RISER
Advantages:
• Internal sulfur removal
• High O2 concentration with restrained temperatures
• Limited size of the boiler and low flue gas recirculation
• Flexible feedstock
(D. Kunii and O. Levenspiel, Fluidization engineering, 2nd ed. Stoneham: Butterworth-Heinemann, 1991)
Mathematical modeling of circulating fluidized bed boilers for coal oxy-combustion - Politecnico di Milano
Oxy-fuel for Industry Oxy-firing has been confirmed by CCP as a
viable technology from a technical and economic standpoint for capturing CO2 from the main emitting component of refinery operations, the Fluid Catalytic Cracking (FCC) unit. This comes as a result of the completion of CCP’s first capture field demonstration, which took place at a Petrobras research facility in Paraná state, Brazil.
CCP is a partnership of major energy companies
Their goal is to advance the technologies that will underpin the deployment of industrial-scale CO2 capture and storage Since its formation in 2000, the CCP has
undertaken more than 150 projects to increase understanding of the science, economics and engineering applications of CCS
Currently in its third phase of activity (CCP3) its members are BP, Chevron, Eni, Petrobras, Shell and Suncor
FCC is a Well Established Technology
FCC Can Also Run in an Oxy-fuel Mode
Pilot Scale Tests were completed in Brazil in May 2011
http://www.co2captureproject.org/reports/FACTSHEET_FCC.pdf?utm_medium=email&utm_campaign=FCC%20results&utm_content=FCC%20results+CID_d83584bbffd71b99bc1b313d0c9b34ce&utm_source=Email%20marketing%20software&utm_term=httpwwwco2captureprojectorgreportsFACTSHEET_FCCpdf
Oxy-fuel for the petrochemical application
A vital difference for oxy-fuel applications is that if a petrochemical feedstock can be burned in a BFBC/CFBC unit then so can coal! By contrast IGCC units that work well for
petrochemicals do not do so well with coal fuels!
Ca Looping Technologies – Requires Oxyfuel FBC Alternative to amines and chilled NH3, which remain to
be demonstrated at utility scales, although they soon will be!
Highly toxic, and sensitive to degradation Employs well established technology designs based
on CFBC, cost competitive with amine scrubbing approaches
Backend, so can fit with carbon capture ready philosophy, also used with gasification applications
Requirements are for demonstrations of technology at larger scales
Quicklime production for cements, and developments of technology are needed to allow such materials to replace existing sources of quicklime (reducing CO2 potential of cement manufacture by 50%)
Conclusions
Limited timeframe to deploy new thermal power units: Technologies to be considered must be near or at the demonstration
phase, or must offer the possibility of back-end retrofits, after new plant is built to avoid billions of dollars of stranded assets
Concerns over natural gas price volatility For fossil fuels with CO2 capture and/or high biomass co-firing rates will
be required if such plants are to achieve emissions equivalent to natural gas firing, co-firing still a major driver for such projects.
New technologies such as CLC are unlikely to change the current situation within the next two decades
On all fronts FBC Technology looks like a clear winner! Major developments include Foster Wheeler’s Supercritical CFBC
Technology, and Flexi-burn® Technologies, but other vendors such as Alstom and B&W are making major strides forward
Oxyfuel FBC applicable in various industries or different applications
Acknowledgements
In particular, Horst Hack of Foster Wheeler North America Corp. for supplying much of the material used in this presentation Filip Johnsson, Chalmers University Dale Simbeck SFA Pacific Ltd. M.C. Romano, Politecnico di Milano Lufei Jia and Yewen Tan,
CanmetENERGY
