Microwave induced co-processing of biomass/coal blends

Co-processing of biomass with coal has become a promising approach for the efficient utilization of biomass and a feasible option to reduce coal consumption. Normally, biomass and coal blends are normally processed using conventional heating methods, such as co-pyrolysis, co-firing and co-gasification. Due to the fact that microwave heating has many advantages against conventional heating methods in terms of its volumetric heating and instant heating nature, in this study, biomass and coal blends were co-processed under microwave heating to enhance possible synergistic effect to improve the yield and quality of products. Biomass and coal blends were prepared in different mass fraction. Both conventional pyrolysis and microwave induced coprocessing tests were carried out. The solid, liquid and gas products were analysed using scanning electron microscopy (SEM) and gas chromatography - mass spectrum (GC-MS). Results showed that in conventional pyrolysis, mole fraction of CO₂ is relatively high whilst that of H2 is relatively low. However, for microwave induced co-processing of biomass coal blends with a mass fraction of biomass around 10wt%, the mole fraction of H₂, CO and CH₄ could be as high as 85%. This indicates the existence of synergy when biomass is co-processed with coal. In the liquid product, it was also found that the distribution of liquid products under microwave induced pyrolysis is much narrow compared with that of liquid products produced under conventional pyrolysis.