Investigation of Biomass Gasification Potential in Syngas Production: Characteristics of Dried Biomass Gasification Using Steam as the Gasification Agent

Abstract

This article assesses the gasification behavior of sawdust using steam as the gasification agent. To do this, a comprehensive model of biomass gasification consisting of four main processes (biomass dehydration, biomass devolatilization, tar combustion, and char gasification) was developed using an Aspen Plus simulator. Two gasification processes were studied: steam-gasification with primary tar combustion (SIM I) and steam-gasification with no pretreatment (SIM II). The effects of the gasification temperature (650–800 °C) and the steam-to-biomass ratio, S/B (1.1–1.8), on the produced gas composition, gas yield, tar yield, the higher heating value of the syngas (HHVgas), H2/CO, carbon conversion efficiency (CCE), and cold gas efficiency (CGE) were investigated. It was found that the gasification strategy had little effect on the CCE but had a significant effect on the produced gas composition and CGE. During steam-gasification with primary tar combustion (SIM I), HHVgas and H2/CO showed higher values, while the tar yield showed lower values. The simulation results also confirmed an insignificant effect of the gasification temperature in the range of 650–800 °C on HHVgas. Regardless of the gasification strategy, it was found that steam-gasification of sawdust achieved the acceptable level of H2/CO and HHVgas at simulated conditions and can be considered as an alternative route for the Fischer–Tropsch synthesis.