STATE-OF-THE ART CFB TECHNOLOGY PAVING THE WAY TO UTILITY SIZE POWER PRODUCTION WITH VERSATILE SOLID BIOMASS FUEL SUPPLY

摘要

Major incentives on renewable power and decreasing consumption have nearly stalled thermal power investments in Europe. While fossil fuels are facing strong political pressures and electricity storage technologies are only feasible for short term needs, there seems to be market for CO2 neutral thermal power capable of grid control as well as CHP/CHPC production. Today's market situation calls for fuel- and load-flexible technologies, while maximum efficiency and economics of scale drive towards utility size solutions. A proposed biomass power project in U.K. is taking the Circulating Fluidized Bed (CFB) combustion technology to the 300-MWe scale with sole biomass fuels. According to the Industrial Emissions Directive (IED, 2010/75/EU), power plant permit conditions must be based on the Best Available Techniques (BAT). BAT Reference Documents (BREFs) include BAT conclusions, which the IED requires to be the reference for setting permit conditions. IED also defines the emission limits for large combustion plants that become effective in existing plants in 2016. The existing BREF documentation is being reviewed, and the new rules specified for SO2, NOx, HCl, HF, Hg and dust will be stricter than the current ones and legally binding, which will affect thermal power investments. The advanced steam parameters, 176 / 40.4 bara, 568 / 568 °C combined with high-chlorine, high-alkali solid biomass fuels call for careful design and operation in order to keep the availability high and lifecycle costs under control. Corrosion estimates based on design tools and process models validated with extensive field data have been prepared to support optimization of the boiler design and materials for this unique case. Dynamic simulations ensure that flexibility needs will be met. This paper presents the key technical features and performance estimates of the state-of-the-art CFB boiler concept developed for the new 300-MWe biomass fired high efficiency power plant.