Thermal Decomposition of Microwave Pre-Treated Biomass Pellets

Studies were carried out to evaluate the influence of microwave pre-treatment on the thermal decomposition of different lignocellulosic biomass pellets and on the yield of volatile compounds. Microwave pre-treatment of biomass pellets was performed using a 700 W heat capacity microwave oven by varying the mw irradiation time of biomass pellets along with estimation of the effect of mw pre-treatment on the mass density and elemental composition of pellets responsible for changes of the thermal decomposition and yield of volatiles during the gasification of pre-treated pellets. Experimental studies of the thermal decomposition of pre-treated biomass pellets and formation of volatile compounds (CO, H2, CxHy) were conducted using a laboratory-scale setup with the heat capacity 5 kW which combines a biomass gasifier and a combustor. The results of the complex study allow to conclude that the microwave pre-treatment of biomass pellets promotes an increase of the weight loss rate by decreasing the mass density, but increasing the surface area and reactivity of the pretreated pellets thus activating the thermal decomposition during the gasification of the pre-treated pellets with a faster and enhanced yield of combustible volatiles. The results of the experimental study suggest that mw pre-treatment of lignocellulosic pellets can be used as a tool to control the thermal decomposition of lignocellulosic pellets and the yield of combustible volatiles.