Syngas Production from Combined Steam Gasification of Biochar and a Sorption-Enhanced Water–Gas Shift Reaction with the Utilization of CO2

Supanida Chimpae,Fasai Wiwatwongwana,Suwimol Wongsakulphasatch,Supawat Vivanpatarakij,Suttichai Assabumrungrat,Weerakanya Maneeprakorn,Thongchai Glinrun

doi:10.3390/pr7060349

Abstract

This research aims at evaluating the performance of a combined system of biochar gasification and a sorption-enhanced water–gas shift reaction (SEWGS) for synthesis gas production. The effects of mangrove-derived biochar gasification temperature, pattern of combined gasification and SEWGS, amount of steam and CO2 added as gasifying agent, and SEWGS temperature were studied in this work. The performances of the combined process were examined in terms of biochar conversion, gaseous product composition, and CO2 emission. The results revealed that the hybrid SEWGS using one-body multi-functional material offered a greater amount of H2 with a similar amount of CO2 emissions when compared with separated sorbent/catalyst material. The gasification temperature of 900 °C provided the highest biochar conversion of ca. 98.7%. Synthesis gas production was found to depend upon the amount of water and CO2 added and SEWGS temperature. Higher amounts of H2 were observed when increasing the amount of water and the temperature of the SEWGS system.

Highlights

Synthesis gas or syngas, which is composed mainly of H2 and CO, can be applied for various downstream processes, e.g., electricity generation or chemical production [1,2,3]
The authors showed that the ratio of syngas production was varied depending upon amount of CO2 fed into the system, gasification temperature, and pressure
Conversion of biochar was firstly investigated by studying the effect of gasification temperature using H2 O and O2 as gasifying agents with a H2 O:O2 :C feed molar ratio of 0.25:0.25:1

Summary

Introduction

Synthesis gas or syngas, which is composed mainly of H2 and CO, can be applied for various downstream processes, e.g., electricity generation or chemical production [1,2,3]. The conversion of biomass by thermochemical processes such as gasification or pyrolysis has been extensively used to produce syngas and is recognized as an environmental-friendly technique as it is carbon-neutral [4]. The thermochemical process can be performed using different operating conditions, i.e., gasifying agent, temperature, pressure, etc., which could yield different amounts and compositions of syngas [5,6,7]. Chaiwatanodom et al [6] studied the production of syngas from biomass gasification using recycled CO2 from the process as a gasifying agent by process modelling using the Aspen Plus program. The authors showed that the ratio of syngas production was varied depending upon amount of CO2 fed into the system, gasification temperature, and pressure

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