Estimation of energy consumption for drying of forest combustible materials during their preparation for incineration in the furnaces of steam and hot water boilers

Abstract

ABSTRACTThe article presents the results of the experimental studies of the processes of heat and mass transfer during the period of thermal preparation of woody biomass for incineration in the furnaces of steam and hot water boilers, made to estimate the energy consumption for its drying. The experiments have been carried out on the equipment, providing a fairly low level of measurement error of the main characteristics of the process of dehydration of forest combustible fuel (FCF) (ambient temperature Tg, sample mass of the material under investigation mi). Mass moisture absorption rates have been established at various temperatures of the drying agent – air (Tg= 333 ÷ 393 K). It is shown that the total drying time τd (under identical conditions) does not depend practically on the type of biomass (the values τd of different FCF can be differed by no more than 8%). According to the results of the experimental studies, the analysis of energy consumption for the process of moisture removal from forest combustible materials has been carried out. It has been established that with the initial moisture content of forest combustible materials from 50% to 70%, the consumption of heat for complete moisture removal is from 10% to 13% of the calorific value of these materials. With increasing ambient temperature, the coefficient of beneficial use of the heat of combustion of the FCF increases.