MOISTURE CONTROL OF A PREDRYING STEP IN A TORREFACTION PROCESS

摘要

There is provided a method of torrefaction of biomass and combustion of generated gases, comprising the steps of: a) drying biomass having an average moisture content of at least 20 %, such as at least 25 % (w/w) to obtain a dried biomass having an average moisture content of 3-15 % (w/w) and a first gas product; b) further drying the biomass from step a) to obtain a dry biomass and a second gas product; c) heating and torrefying the biomass from step b) to obtain torrefied material and a third gas product; and d) collectively combusting of the second and the third gas product without the first gas product.