Process simulation of steam-gasification of biomass for H2 -enriched gaseous fuel production

Abstract

Abstract Gasification is recognized as an environmentally friendly process for converting low-quality biomass materials into a valuable gaseous fuel. In this work, a novel simulation model for air/steam gasification of biomass (wood pellet) is developed using ASPEN plus to study the feasibility of producing H2-rich syngas. Benzene and naphthalene were used as tar model compounds and olivine was used as a catalyst. The model developed in this research includes five main sections, which are: dehydration reactor (DRY), decomposition reactor (PYR), tar cracking reactor (TAR-C), gasification reactor (GASIF1) and catalyst reactor (GASIF2). The model was validated with the experimental data available in the published literature and a good agreement was achieved. In the gasification section, influence of air ratio, AR (0.2-0.4), steam/biomass ratio, SBR (0-1.0) and temperature (725-875 °C) was studied. It was found that the addition of olivine not only decreases the tar yield, but also somewhat improved CGE by increasing H2 content in the gas stream. CCE also increased slightly, which can be due to the conversion of the carbon content in the tar to light hydrocarbons (CH4) and other carbon-based gases. In addition, air-steam gasification of wood pellet with olivine could achieve the highest H2 content of 15.17 vol% under optimal conditions (AR=0.3, SBR=0.66 and T=825 °C), in which the CCE and CGE reached 87.35% and 45.46%, respectively.