Production of hydrogen-rich syngas from biomass gasification by double step steam catalytic tar reforming

This study focused on the catalytic steam reforming of tar produced from updraft gasification of hazelnut shells. Two streams of syngas were extracted from different heights in the reaction bed of a gasifier able to treat 20–30 kg/h of biomass. The syngas was then conveyed to the new built catalytic section for further processing. A two-bed in series approach was tested. This design enables the use of dolomite as a cheap catalyst and as chemical trap for sulphur and chlorine, mitigating potential damage to the more performant and complex catalyst Ni/CeO2/Al2O3. The latter catalysts underwent comprehensive characterization to evaluate its efficiency. The reforming of tar in both streams achieved a remarkable >98.5% yield. The study highlights the diverse roles of dolomite in the gasification process and the positive effects of CO2 pre-adsorption, enhancing H2 content, cleanliness and heating value of the upgraded syngas.