VERIFICATION OF METHOD FOR ESTIMATING COMBUSTION EFFICIENCY IN A BUBBLING FB COMBUSTOR

Abstract

The article refers to a mathematical method for estimating the efficiency of the combustion process in bubbling fluidised bed conditions. The calculation procedure used in this work is given elsewhere [1, 2] and, here, it is only briefly described. The objective of the present investigation is to validate the mentioned method when using brown coal as a fuel in a laboratory fluidised bed combustor. Particular attention is devoted to the subject of elutriation of fuel particles out of the combustor, considering the fact that it is one of the most important factors limiting the combustion efficiency and the furnace design as well. The work presented here contains the conditions and some results of experimental research in heat losses resulting from the phenomenon of elutriation of combustible particles [3]. Experiments were carried out in a combustor with an inner diameter of 200 mm and a height of 1200 mm. A numerical testing of the method for estimating the combustion efficiency was accomplished within a bed temperature range from 780 °C to 900 °C and a fluidising velocity from 1.20 to 1.32 m/s. The results achieved were compared with the experimentally obtained data. Besides the appearance of some deviations, it may be stated that the results are reasonable and in line with the expectations.