Development of high efficiency refuse fired boiler applied in circulating fluidized bed combustion

Abstract

The high efficiency and low pollutant thermal recycling technologies for combustible refuse, for example, municipal waste, have been developed by using the circulating fluidized bed boiler. MHI's circulating fluidized bed boiler is equipped with the external heat exchanger and able to control heat adsorption rate in the combustor. Therefore, the various kinds of refuse can be used and the load swing range is very wide. As there is little corrosive gas such as HCl in the external heat exchanger, a superheater can be installed and high temperature and high pressure steam can be generated. And NOx emission is low, DeSOx rate by limestone is high and dioxin emission is also low, because the temperature in the combustor is homogeneously 850°C and the residence time of combustion gas is several seconds. MHI has already constructed a coal and paper sludge co-fired boiler, which has been operating very favorably. The combustion tests of municipal waste, RDF (Refuse Derived Fuel), and waste plastics etc. have been also executed by the test circulating fluidized bed furnace and good results have been obtained as expected before. In addition to this combustion technology, high temperature corrosion resistant material, pollutant gas and fly ash disposition technologies are also necessary.