Research of volatile release duration at wood pellets combustion

Abstract

For development of high intensive burners it is necessary explore possibilities to intensify all stages of solid fuel combustion. The features of thermal decomposition (thermolysis) of wood pellets with volatile substances release in furnace of boiler or heat generator were regarded. Calculation of volatile release duration based on available dependencies, derived using slow heating of wood particles in an inert atmosphere, gives results that significantly exceed observed at combustion. Procedure of experimental investigation to determine duration of volatile release period at thermolysis of wood pellets, having 6 mm in diameter, in an oxidizing atmosphere in the muffle furnace is described. The influence of muffle temperature, humidity and length of pellets were investigated. Experimentally determined period of volatile release in oxidizing atmosphere is from 2 up to 4 times less than that estimated for inert atmosphere. Dependence of volatile release duration from temperature is exponential in nature, and that from the pellets length is close to hyperbolic tangent. Period of volatile release increases with the pellets length increasing up to 30 mm and at further increasing of pellet length remains constant. The period of volatile release for wood pellets with moisture content W = 10.1% is 20% more compared with that for dry pellets.