A Computational Fluid Dynamics Investigation of the Utilization of Waste Biomass Fuels for Syngas Production in A Downdraft Reactor

Abstract

Biomass gasification, one of the gasification technologies, is among the technologies being developed for environmentally friendly and clean energy production of waste non-forest wood products and is a common subject of study in this field. In this study, gasification of three different biomasses (pine wood, pinecone, and hazelnut shell) in a downdraft reactor was analyzed and simulated. Ansys-Fluent commercial software (version 2020) was used for the analysis and calculations. A small-scale gasification reactor was modeled, and fuel and air feed conditions were determined. The air-fuel ratio required for gasification was analyzed with different equivalence ratios (0,15-0,35) to demonstrate the difference from stoichiometric combustion. According to the reactor gas temperature distribution and the content of the synthesis gas produced, it was determined that the equivalence ratio of 0,20 is suitable for a gasifier of this scale. By reaching temperatures above 900 °C in the reactor, the contours of CO, H2O and CH4 combustibles in the synthesis gas content in the reactor were shown and its proportions in the mixture were determined. The results were found to be consistent with the values in scientific literature. It was revealed that waste biomass can be used in clean energy production, and it is possible to develop fuel and capacity specific gasification reactors with CFD analysis.