Currently, Turkey is amongst the world’s fastest growing economies, and country’s energy demand has been rapidly growing. Due to over 10 GT of proven domestic lignite reserves(IEA), lignite is considered a feasible alternative for large-scale electricity production compared to imported coal.
On the other hand, Circulating fluidized bed (CFB) has emerged among the leading combustion technologies for utility-scale solid-fuel-fired power plants, especially in combustion of lignites. Benefits of the technology include high efficiency and availability and supreme fuel flexibility with low emissions. Today, nearly 440 Foster Wheeler’s CFB boilers have been sold with both subcritical and supercritical steam values. To reach required emission limits in economic way, also additional emission control technologies, such as the circulating fluidized bed scrubbing (CFBS) technology has been applied together with CFB combustion technology to optimize the sulphur capture from flue gases. This is a viable pathway for addressing multi-pollutant control in a cost effective manner.
During the past 40 years Foster Wheeler has supplied nearly 300 CFB boilers designed for coal including lignite with total thermal capacity of 71 GWth. All the boilers utilize the same circulating fluidization principle; however, depending on the quality of fuel, the boilers may differ in design and operation. The size of CFBs designed for lignite as primary fuel can vary in a broad range of steam capacity, form industrial to large-scale utility boilers, up to 800 MWe.
In this paper, economic benefits of combusting domestic lignite compared to imported coal are highlighted. Furthermore, a recent Foster Wheeler’s CFB project firing Turkish lignite as the main fuel, Harbin Electric International Co. Ltd. (HEI) Soma (2x255MWe), is presented. This is currently the biggest CFB boiler on Turkish lignite. Also the design and process of related flue gas cleaning concept featuring best available CFB (Circulating Fluid Bed) scrubbing technology (BAT), is discussed. There are two identical flue gas cleaning lines, which consist of CFB scrubber including bag-house with solids re-circulation.
Keywords: Utility CFB technology, CFB scrubbing technology, Lignite firing