Developments in circulating fluidised bed combustion

While pulverised coal combustion (PCC) remains the dominant technology in the power generation sector, a significant minority of plant commissioned is based on circulating fluidised bed combustion (CFBC). CFBC offers specific advantages over PCC, particularly in the utilisation of low quality coals, and mixtures of coal with other fuels, including wastes. Since its initial deployment, CFBC has continued to evolve. Recently, significant advances have been made in scaling-up the CFBC units and in the adoption of supercritical steam parameters. The engineering designs and operation of the CFBC systems have also been optimised leading to improvements in plant reliability and availability, and plant economics. The CFBC technology is emerging as a real competitor to PCC system. For PCC and CFBC boilers, oxy-fuel combustion systems that produce high purity CO2 exhaust streams ready for carbon capture are under development. Oxy-CFB technology may have some advantages over oxy-PC combustion designs but there are challenges in the development of the concept and design of oxy-CFB boilers. This report reviews the recent developments in CFBC technology and how it fits within carbon capture and storage strategies. Acronyms and abbreviations 2 IEA CLEAN COAL CENTRE AFT adiabatic flame temperature CCS carbon capture and storage CFBC circulating fluidised bed combustion CIUDEN Fundación Ciudad de la Energía cm centimetre COE cost of electricity CPU carbon purification and compression unit EHE external heat exchangers EU European Union FBC fluidised bed combustion FBHE fluidised bed heat exchanger FW Foster Wheeler HHV high heating value IEA CCC International Energy Agency The Clean Coal Centre km kilometre kg/m2.s kilograms per square metre per second kW kilowatt LHV low heating value mm millimetre MPa mega pascal MWe megawatt electric MWh megawatt hour MWth megawatt thermal NETL The National Energy Technology Laboratory, USA PC pulverised coal PCC pulverised coal combustion R&D research and development TDC Technology Development Centre t/h tonnes per hour US DOE US Department of Energy VOC volatile organic compounds vol% percentage by volume VTT Technical Research Centre of Finland WDF waste derived fuel