Performance Analysis of an Integrated Fixed Bed Gasifier Model for Different Biomass Feedstocks

Sharmina Begum,Naveed Ramzan,Mohammad Rasul,Delwar Akbar

doi:10.3390/en6126508

Abstract

Energy recovery from biomass by gasification technology has attracted significant interest because it satisfies a key requirement of environmental sustainability by producing near zero emissions. Though it is not a new technology, studies on its integrated process simulation and analysis are limited, in particular for municipal solid waste (MSW) gasification. This paper develops an integrated fixed bed gasifier model of biomass gasification using the Advanced System for Process ENngineering (Aspen) Plus software for its performance analysis. A computational model was developed on the basis of Gibbs free energy minimization. The model is validated with experimental data of MSW and food waste gasification available in the literature. A reasonable agreement between measured and predicted syngas composition was found. Using the validated model, the effects of operating conditions, namely air-fuel ratio and gasifier temperature, on syngas production are studied. Performance analyses have been done for four different feedstocks, namely wood, coffee bean husks, green wastes and MSWs. The ultimate and proximate analysis data for each feedstock was used for model development. It was found that operating parameters have a significant influence on syngas composition. An air-fuel ratio of 0.3 and gasifier temperature of 700 °C provides optimum performance for a fixed bed gasifier for MSWs, wood wastes, green wastes and coffee bean husks. The developed model can be useful for gasification of other biomasses (e.g., food wastes, rice husks, poultry wastes and sugarcane bagasse) to predict the syngas composition. Therefore, the study provides an integrated gasification model which can be used for different biomass feedstocks.

Highlights

The demand for energy security has been increasing globally to meet the vital needs of humans’daily lives: producing electricity, powering vehicles, heating or air-conditioning homes, producing life-saving medicines and processing food, etc
The developed simulation model has been validated using experimental data for municipal solid wastes (MSWs) and food waste gasification in a lab-scale hybrid gasifier published by Naveed et al [11,17]
The simulation was done for syngas composition, such as, H2, carbon monoxide (CO), CO2, CH4 and N2 using the experimental condition for both MSWs and food wastes

Summary

Introduction

The demand for energy security has been increasing globally to meet the vital needs of humans’daily lives: producing electricity, powering vehicles, heating or air-conditioning homes, producing life-saving medicines and processing food, etc. Biomass gasification is one of the popular processes that produces energy in the form of synthesis gas and at the same time reduces the environmental hazards of raw biomasses. It can reduce the dependency on imported energy and would help ensure energy security. Biomass gasification is a continuous substoichiometric [oxygen (O2) starved] burning process which burns biomass (e.g., solid waste) in a reactor generating a syngas and pyrolysis liquids (tars) as fuels. It takes place in the presence of a limited amount of oxidizer (air, O2 or steam).

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