Predicting the ash behavior of different fuels in fluidized bed combustion

One of the key advantages of the fluidized bed combustion technol. is its potential of burning a great variety of fuels and even fuel mixts. in an efficient way.  Besides many different coals, wood, other biomass and also waste derived fuels have been successfully demonstrated in a no. of FBC installations around the world.  However, some fuels or fuel mixts. may cause problems in FBC application.  One potential problem may be assocd. with the behavior of the fuel ashes in the furnace and flue gases.  The two main ash related problems are bed agglomeration or fouling of the convection surfaces.  Consequently, it is of major interest to be able to est. the behavior of any new fuels or fuel mixts. in advance before trying them in a full-​scale unit.  This paper presents a method to predict the performance of fuels at FBC conditions.  The aim is to predict the fouling tendency of the fly ash formed during burning of a fuel or fuel mixt. in a FBC.  The method is based on a combination of the advanced fuel anal. technique "chem. fractionation anal." and thermodn. phase equil. calcns.  With these we describe the thermal behavior of the fuel ash components in the furnace and flue gases.  The method is demonstrated for selected solid fuels including coal, peat and some wood based biomasses.  Selected results are compared with full-​scale measurements.