Erosion and corrosion in advanced coal fired FBC systems

Worldwide, advanced coal-fired power generation systems are being introduced that offer significant economic and environmental advantages over pulverised fuel (pf) firing. Many of these systems are combined cycles based on fluidised bed combustion and/or gasification. In such combined cycles, materials selection and performance are key factors in determining plant availability. Consequently material evaluation studies for the various components form an integral part of any development programme. This paper provides a review of materials issues for two advanced technologies, namely pressurised fluidised bed combustion (PFBC) and the British Coal Topping Cycle. Particular attention is paid to the approach adopted to overcome these issues and their influence on plant design. PFBC development in the United Kingdom is outlined. Erosion/corrosion issues within the in-bed heat exchanger and the solutions that will allow a commercially acceptable tube bank lifetime to be realised are discussed. The British Coal Topping Cycle system, which is under development, is described. Some of the materials issues are identified and the programme being undertaken to ensure acceptable component lifetimes is reviewed