A Rapidly Emerging WTE Technology: Circulating Fluid Bed Combustion

The management of solid waste has become a major problem and budget item of municipalities, especially in rapidly developing cities. The only alternatives for post-recycling waste are sanitary landfills, which require large tracts of land, and waste-to-energy (WTE) plants which are costly to build; an additional problem in the developing world is the high (>50%) organic and moisture content of the municipal solid waste (MSW). This paper examines the emergence of the circulating fluidized bed (CFB) in China. This technology is less capital intensive than the dominant moving grate combustion and, also, can efficiently process feedstock of heating value as low as 5 MJ/kg, with continuously dry discharge of bottom ash. Since the beginning of the 21st century, 47 CFB plants, of total capacity of over 14.6 million ton per year of MSW, have been built in China. The case study to be examined in this paper is the new 800 ton per day WTE unit, one of four units of total capacity of 2,300 tons per day serving the city of Cixi. The technology used was developed and tested extensively by Zhejiang University in the city of Hangzhou.