Depolimerization of Sugarcane Bagasse by Microwave-assisted Pyrolysis

Abstract

Technologies and processes that minimize the dependence on petroleum products are among the most significant challenges of our time. Lignocellulosic biomass, such as sugarcane bagasse, is a promising alternative for obtaining a wide range of products, such as value-added chemicals and fuels. Pyrolysis is one of the most efficient ways to convert biomass into products with high calorific power, such as pyrolysis gas, bio-oil, and biochar. In this work, sugarcane bagasse with different moisture content (3.1 and 13.2%) was pyrolyzed using a microwave-assisted pyrolysis (MAP) system with silicon carbide (SiC) as a microwave absorber. The temperature profiles and fractions analysis helped to defining the best pyrolysis parameters: 23 min reaction time, 100% microwave power (644.70 Watts), 60 g of SiC, over setpoint temperature of 450 °C, and inert gas flow rate of 3 L/h. Analysis of the liquid fraction by GC-MS identified alcohols, aldehydes, carboxylic acids, and lignin derivatives in bio-oil composition. A slightly different bio-oil composition showed up for the sample with higher moisture content. Likewise, the solid fractions (biochar) were characterized by microscopy, showing a different surface morphology acording to the moisture content. In conclusion, MAP can be a promising alternative for achieving valuable magerials and small molecular mass compounds from sugarcane bagasse.