Applied Chemical Engineering

Design of a Downdraft Gasifier for Biomass Gasification and Comparison of the Performance of Two Different Gasification Agents

Sherif Elshokary

Faculty of Engineering at El-Mattaria, Helwan University

Sherif Farag

Faculty of Engineering at El-Mattaria, Helwan University; Ecole Polytechnique, University of Montreal; RMTech for Environmental Solutions Inc.

Bitu Hurisso

Chemistry Department, Atlantic Centre for Green Chemistry, Saint Mary’s University

Nazih Noaman Bayomi

Faculty of Engineering at El-Mattaria, Helwan University

Mostafa Ismail

Faculty of Engineering at El-Mattaria, Helwan University

Keywords: gasification, downdraft gasifier design, exhaust gas producer gas

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Abstract

A project was undertaken to construct and assess the viability of a downdraft biomass gasifier as an alternative solution for delivering sustainable energy and electricity in developing nations. The gasifier, made of stainless steel, was specifically designed for wood pellets and tested using exhaust gas and air as gasification agents. The flow rate of the primary gasification agent was measured at 440 m3/h, and the producer gas's exit temperature (ranging from 300-650 ºC) was analyzed based on the moisture content of the biomass feedstock. The temperature within the reaction zone varied depending on the equivalence ratio (ER) for exhaust gas (ranging from 700-974 ºC) and for air (ranging from 620-850 ºC). Additionally, the temperature was influenced by the moisture content, with ranges of 830-1050 ºC for exhaust gas and 850-1070 ºC for air. The syngas produced consisted mainly of carbon monoxide (14.4-19.2%), hydrogen (16-20%), carbon dioxide (7.1-11.2%), and a small amount of methane (2-3%). Based on future research, downdraft gasifiers emerge as the most suitable technology for electricity generation in developing countries, positioning them as a significant and reliable source of power.

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