ADVANCED UTILITY CFB TECHNOLOGY FOR CHALLENGING NEW SOLID BIOMASS FUELS

摘要

New boundaries for power plant operation are being set in the European energy production markets. Several factors, such as biomass subsidies, have increased the interest in large scale, commercially feasible biomass fired power plants. To further increase and ensure the profitability of these plants, investors and plant operators have widened their fuel portfolios to include low cost biomass, such as encroaching wood species and agro-pellets from Europe, South America, Africa and USA. This trend has resulted in increased pressure to develop utility power plant technology that is capable of both flexible and highly efficient operation with higher steam parameters, while firing these challenging solid biomass fuels. European utility sized power plants now have new requirements and expectations for their operational capability: to fire new and challenging types of biomass in highly efficient large-scale power plants while maintaining high plant availability. Circulating Fluidized Bed (CFB) combustion technology is increasingly becoming the market-leading technology used in the large-scale utility power sector firing a broad range of solid biomass fuels, due to its well-known benefits such as fuel flexibility, high efficiency, availability, and reliability. However, detailed knowledge of biomass specifications and full understanding of their variability of supply are paramount to design boilers with the highest efficiency and availability, and to operate them in the most economical way. After introducing the market drivers and technical challenges of firing new types of solid biomass and residues in utility boilers, this paper presents the key technical features needed in CFB boilers firing challenging biomass, in order to overcome challenges associated with plant availability. The paper also reviews relevant boiler references in commercial operation: 110- MWth CFB of Kraftringen Energi AB, ?rtofta, Lund, Sweden, designed to burn wood biomass, demolition wood and peat; 447-MWth CFB of GDF SUEZ, Po?aniec, Poland, designed for wood chips and agro biomass; and 154-MWth CFB of ZE PAK, S.A., Konin, Poland, designed for wood and crop waste.