Hydrogen-Rich Gas Production by Sorption Enhanced Steam Reforming of Woodgas Containing TAR over a Commercial Ni Catalyst and Calcined Dolomite as CO2 Sorbent

Mario Sisinni,Enrico Bocci,Andrea Micangeli,Vincenzo Naso,Andrea Di Carlo

doi:10.3390/en6073167

Abstract

The aim of this work was the evaluation of the catalytic steam reforming of a gaseous fuel obtained by steam biomass gasification to convert topping atmosphere residue (TAR) and CH4 and to produce pure H2 by means of a CO2 sorbent. This experimental work deals with the demonstration of the practical feasibility of such concepts, using a real woodgas obtained from fluidized bed steam gasification of hazelnut shells. This study evaluates the use of a commercial Ni catalyst and calcined dolomite (CaO/MgO). The bed material simultaneously acts as reforming catalyst and CO2 sorbent. The experimental investigations have been carried out in a fixed bed micro-reactor rig using a slipstream from the gasifier to evaluate gas cleaning and upgrading options. The reforming/sorption tests were carried out at 650 °C while regeneration of the sorbent was carried out at 850 °C in a nitrogen environment. Both combinations of catalyst and sorbent are very effective in TAR and CH4 removal, with conversions near 100%, while the simultaneous CO2 sorption effectively enhances the water gas shift reaction producing a gas with a hydrogen volume fraction of over 90%. Multicycle tests of reforming/CO2 capture and regeneration were performed to verify the stability of the catalysts and sorbents to remove TAR and capture CO2 during the duty cycle.

Highlights

Among renewable energy sources biomass is attracting increasing attention due to its abundance and low cost
The first one is called “pre-breakthrough” and corresponds to the highest efficiency of CO2 sorption, water gas shift and topping atmosphere residue (TAR) reforming reactions together and is represented by a plateau until the reactions are at equilibrium
The results obtained by catalytic steam reforming of a raw gas resulting from biomass gasification and simultaneous CO2 capture were presented and discussed

Summary

Introduction

Among renewable energy sources biomass is attracting increasing attention due to its abundance and low cost. Biomass gasification is intended to perform an important role in the production of a H2-rich syngas [1]. Biomass gasification (with steam, and/or oxygen) is a thermochemical process that produces a fuel syngas rich in hydrogen and carbon monoxide, with additional significant quantities of carbon dioxide and methane. Atmosphere Residue (TAR), that is a complex mixture of cyclic and polycyclic aromatic hydrocarbons [2], known for its toxicity and cancerous properties. Unacceptable levels of TAR cause operational problems in downstream processes, such as internal combustion engines or gas turbines [3]. Catalytic steam reforming seems to represent the best method to both reform methane and eliminate

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