Hydrogen and syngas production by hybrid filtration combustion: Progress and challenges

Hydrogen (H2) and syngas (a mixture of H2 and carbon monoxide) can be thermochemically produced from various sources, such as fossil fuels, biomass, water, and solid wastes, via steam reforming, dry reforming, and partial oxidation. Hybrid filtration combustion (HFC) has been introduced to produce H2/syngas by gasifying solid fuels or by simultaneously reforming gaseous and solid fuels. This article presents a comprehensive review of HFC modeling, development of HFC reactors, industrial applications, and future directions. Until now, several mathematical models have been proposed and analytically and numerically solved with novel approaches to the relatively complex chemical kinetics found in these reactors. The HFC reactors for solid fuel gasification and simultaneous homogeneous and heterogeneous reactions have shown high temperatures in the reaction wave (900–2300 K) due to high heat recirculation inside. The geometry and orientation, hybrid porous bed composition, gasifying agent, and mode of operation are crucial parameters for optimizing the hydrogen and syngas yield. The various solid feedstocks studied include coal, biomass, and polyethylene, and the gasifying agents used are air, steam, carbon dioxide, and premixed air/fuel flows. At the industrial scale, HFC has been successfully implemented for producing hydrogen/syngas from municipal solid waste. The present review has revealed the promising potential of this technology as an energy-efficient and sustainable alternative to produce H2 and syngas from various solid and gaseous feedstocks.