Microwave drying of biomass and its effect on pyrolysis characteristics

The influence of microwave drying on the pyrolysis of biomass was investigated compared with conventional air drying. The aim of this work is to seek the feasibility of using microwave drying technique in fast pyrolysis of biomass during pretreatment of the feedstock. The drying tests show that the drying rate of microwave oven is far faster than that of electrical oven. The inner pore characteristics of dried biomass are improved at higher drying rate. The thermogravimetric and kinetic analysis indicate that the microwave drying treatment promote the decomposition of biomass, especially cellulose and hemicellulose, and prevent the secondary reactions of primary vapor to a certain extent at the same time. As a result, the yield of bio-oil from biomass pyrolysis in a fluidized-bed reactor increases slightly. Thus microwave drying is a technically and economically feasible pretreatment method for fast pyrolysis of biomass and more in-depth works are needed to be carried out next step.