For cleanly and high efficiency utilization with coal, a new system has been developed at Institute for Thermal Power Engineering, Zhejiang University. The coal is first gasified, the produced fuel gas is used for industrial process or town gas as well as fuel for gas turbine. The residue char from gasifier is burned in a circulating fluidized bed combustor to generate steam. The steam can be used by steam turbine, process heating, refrigeration, and air conditioning, the ash is used to produce construction materials, metal, such as vanadium and uranium, can be extracted if the content of metal in coal is high. The very important part of the system is the combined sub-system of gasifier and combustor. A series of fundamental experiments have been finished for the sub-system. The results show that the system can produce gas and steam simultaneously and the gas heating value is 10000-14000 KJ/NM3, and the fuel conversion is over 90%. Furthermore, the system has the advantages of low pollutant emissions, low investment and high economical efficiency. A demonstration system has been constructing at Yangzhong Thermal Power Station in Jingshu Province. It can produce 3500NM3/H dry gas and 75T/H steam. The CFB Boiler has already operated Since April, 1995. The operation results show it has high efficiency, good fuel adaptability, and high load turndown ratio.
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