TRANSACTION PAPER

CFB technology provides solutions for reducing CO₂ emissions

V. Barišić; E. Coda Zabetta; T. Eriksson; A. Hotta; S. Kokki; K. Nuortimo; J. Palonen

Foster Wheeler Energia Oy, Finland

SYNOPSIS

The scheduled power cuts of early 2008 were a disturbing reminder that South Africa needs to expand its power-generating capacity. Low-grade and discard coals, of which South Africa has much, are a source of energy and amenable to combustion in circulating fluidized beds (CFBs). Foster Wheeler (FW) has a long ecord in developing this technology in boilers. The technology is flexible in burning a variety of fuels; low-grade, high-ash coals, good quality bituminous and anthracite coals, and biomass and waste fuels have all been used. CFB boilers are efficient, reliable and can be designed to meet tight emission standards.
In recent years once-through supercritical (OTSC) CFB technology has been developed. It enables the next stage in CFB development to proceed to a medium-scale (500 MWe) utility in such projects as Łagisza, which runs at a net efficiency of nearly 44%. Scaling the technology up to 800 MWe with a net efficiency of >45% is planned to be commercial during 2009.
CFB technology can reduce CO2 emissions in the repowering of coal-fired and greenfield power plants. It does so through greater efficiencies and by co-combusting coal with biomass. FW has also developed CFB technology for the gasification of biomass, as, for example, in a pressurized gasifier to produce syngas, which can be used for the production of biodiesel, thereby reducing CO2 emissions from vehicles.
Carbon capture and storage (CCS) can potentially cut CO2 emissions in the generation of power from fossil fuels in the short term, provided that it gains public acceptance, that the required regulatory framework is created, and that emission-trading mechanisms or other incentives provide a solid return on the major investments required. Oxyfuel combustion is an option in CCS; Foster Wheeler is adapting its CFB combustion technology for oxyfuel combustion to meet this challenge. It is developing Flexiburn ™, which enables a plant to be operated either with or without carbon capture.
This paper describes the status of CFB technology in terms of boiler efficiency and fuel flexibility. It highlights the advantages of CFB technology for oxyfuel combustion, presents a development plan for Flexi-burn™, and discusses a pressurized gasifier for biodiesel applications.

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References

1. BARIŠIĆ, V. and HUPA, M. On changes in bed-material particles from a 550 MWth CFB boiler burning coal, bark and peat. Fuel 86, 2007, pp. 464−468.         [ Links ]

2. CODA ZABETTA, E., BARIŠIĆ, V., PELTOLA, K. and HOTTA, A. Foster Wheeler Experience with Biomass and Waste in CFBs. 33rd International Technical Conference on Coal Utilization & Fuel Systems, Clearwater, Florida, USA, 2008.         [ Links ]

3. ERIKSSON T., SIPPU O., HOTTA A., ZHEN FAN, MYÖHÄNEN K., HYPPÄNEN T. and PIKKARAINEN T. Oxyfuel CFB Boiler as a Route to Near Zero CO2 Emission Coal Firing. POWER-GEN Europe 2007, June 26-28, 2007, Madrid, Spain.         [ Links ]

4. HILTUNEN, M. and BARIŠIĆ, V.; Coda Zabetta, E. Combustion of Different Types of Biomass in CFB Boilers. 16th European Biomass Conference, 2008, Valencia, Spain.         [ Links ]

5. HOTTA, A., NUORTIMO, K., ERIKSSON, T., PALONEN, J. and KOKKI, S. CFB Technology Provides Solutions to Combat Climate Change. 9^th International Conference on Circulating Fluidized Beds, 2008, Hamburg, Germany.         [ Links ]

6. HOTTA, A., UUS, M. and PARKKONEN, R. Enhanced Performance Using CFB Boilers to Fire Oil Shale Compared to PC Technology. POWER-GEN Europe 2005, Milan, Italy.         [ Links ]

7. HOTTA, A. and VENÄLÄINEN, I. Design and Scale-up Philosophy of Onethrough CFB Boilers with Supercritical Parameters. VGB PowerTech 4, 2006, pp. 66−71.         [ Links ]

8. JÄNTTI, T., ERIKSSON, T., HOTTA, A., HYPPÄNEN, T. and NUORTIMO, K. Circulating Fluidized-bed Technology-toward zero CO2 Emissions. POWER-GEN Europe 2006, Cologne, Germany.         [ Links ]

9. NAVARRETE FERNÁNDEZ, E. Polish Operating Experience from Burning Coal, Coal Washery Reject and Brown Coal in Circulating Fluidized Bed Boilers. Enerji 2003, Istanbul, Turkey.         [ Links ]

10. PSIK, R., JABLONSKI, J. and WYSZYNSKI, J. Turów Rehabilitation Project-The World's Largest CFB Repowering Project, POWER-GEN Europe, 2005, Milan, Italy.         [ Links ]

11. PYYKKÖNEN, A. and HOTTA, A. Foster Wheeler's 2*150 MWe CFB Boilers Started up Successfully in NPS Power Plant in Thailand. POWER-GEN Asia 2000, Bangkok, Thailand.         [ Links ]

12. PHYLLIS: The Composition of Biomass and Waste; Energy Research Centre of Netherlands (ECN), Unit Biomass: Petten, The Netherlands (http://www.enc.nl.phyllis)        [ Links ]

13. VENÄLÄINEN, I. and PSIK, R. 460 MWe Supercritical CFB Boiler Design for Lagisza Power Plant. POWER-GEN Europe 2004, Barcelona, Spain.         [ Links ]