Effects of Various Reactive Gas Atmospheres on the Properties of Bio-Oils Produced Using Microwave Pyrolysis

Abstract

Fast pyrolysis of lignocellulosic biomass produces organic liquids (bio-oil), biochar, water, and noncondensable gases. The noncondensable gas component typically contains syngas (H2, CO, and CO2) as well as small hydrocarbons (CH4, C2H6, and C3H8). To understand the influence of reactive gas in various pyrolysis processes, we have employed a laboratory scale microwave reactor and performed pyrolysis of switchgrass under varying gaseous atmospheres and characterized the bio-oils obtained. The batch (100 g of biomass) microwave pyrolysis was performed at 900–1000 W over the course of 7 min in the presence of a microwave absorber (10 g of activated charcoal). The products formed were quantified and the bio-oils were characterized by GC–MS, elemental analysis, Karl Fischer and TAN titrations, bomb calorimetry, and 13C NMR spectroscopy. Pyrolysis experiments performed under a N2 atmosphere were used as the control and then compared to experiments performed under various reactive gases (CO, H2, and CH4) and a ...