Issue 15, 2023

Effects of throat sizing and gasification agents in a biomass downdraft gasifier: towards CO2-free syngas production

Abstract

The gasification process in a downdraft biomass gasifier is investigated using Computational Fluid Dynamics (CFD). The aim is to develop a novel approach to reduce CO2 emissions from producer syngas while increasing the higher heating value (HHV). To this end, the effects of varying the throat diameter of the gasifier and gasifying media (air and oxygen) on the performance of gasification are investigated. The results reveal that as the throat ratio decreases for oxy-gasification, more CO, H2, and CH4 are produced, thus resulting in a HHV of 12.1 MJ Nm−3. For the same working conditions (ER, MC, and feedstock), the suggested design/optimum throat ratio of 0.14 is found to reduce CO2 by ∼55% compared to any other higher throat ratios, while simultaneously increasing HHV by ∼20% for both air and oxy-gasification cases. Additionally, the suggested throat ratio increases the gasification efficiency, carbon conversion and producer gas yield by 19%, 33%, and 22% respectively. Therefore, it shows a significant potential for CO2-free syngas production in the gasification process, demonstrating a promising technique that does not require any solvents, catalysts, absorbers, or additional CO2 removal. Lower throat ratios further favour the higher yield of syngas, HHV, gasification and conversion efficiencies, with better gasifier performance.

Graphical abstract: Effects of throat sizing and gasification agents in a biomass downdraft gasifier: towards CO2-free syngas production

Article information

Article type
Paper
Submitted
02 Mar 2023
Accepted
22 Mar 2023
First published
04 Apr 2023
This article is Open Access
Creative Commons BY license

RSC Adv., 2023,13, 10221-10238

Effects of throat sizing and gasification agents in a biomass downdraft gasifier: towards CO2-free syngas production

A. M. Salem and M. C. Paul, RSC Adv., 2023, 13, 10221 DOI: 10.1039/D3RA01408H

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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