Advanced circulating fluidised bed technology (CFB) for large-scale solid biomass fuel firing power plants

摘要

Nations worldwide are taking initiatives to counteract global warming by reducing their greenhouse gas emissions. The European Union is playing a leading role by setting its 20-20-20 targets aiming at the reduction of its greenhouse gas emissions by 20% compared to the reference year of 1990, increasing its share of renewable energy to 20% in its primary energy consumption and improving energy efficiency by 20% with all three target met by the year 2020. Efforts to increase boiler efficiency and the use of biomass and other solid renewable fuels are well in line with these objectives. Circulating fluidised bed boilers (CFB) are ideal for efficient power generation, capable to fire a broad variety of solid biomass fuels from small CHP plants to large utility power plants. Advanced Bio CFB (ABC) technology represents the state of the art for large-scale power generation from solid biomass fuels. The Advanced Bio CFB technology further improves the well-known benefits of earlier CFB technologies such as superior fuel flexibility, inherently low emissions, and high availability. Today, the Advanced Bio CFB technology offers efficient sub-critical boilers up to 600 MWe for 100% biomass firing. This technology also offers supercritical steam parameters for biomass and coal co-firing applications up to 800 MWe. This is the result of continuous and determined development work, based on experience and data from ovder 400 CFB reference boilers, of which over 50 are designed for biomass, and nearly 50 for waste containing biodegradable fractions, which are effectively CO_2 neutral. After introducing the market drivers and technical challenges of firing solid biomass and residues in utility boilers, this article presents the key technical features adopted in CFB boilers to overcome such challenges, ultimately defining the Advanced Bio CFB technology. The paper reviews relevant boiler references in commercial operation, and finally reveals the range of applicability and performance of latest CFB designs available on the market.