Siderite/Concrete catalysts for H2-enriched gas production from biomass steam gasification

In this study, granulated siderite/concrete-based catalysts are proposed for in-situ applications in biomass steam gasification, seeking H-2-enrichement by the contribution of water gas shift and CO2 adsorption. A cost-effective procedure has been applied for the preparation of granulated catalysts. Water Gas Shift reaction was studied in a fixed bed reactor and Taguchi experimental design was used to elucidate the relevance of experimental parameters on catalyst performance. The results show that the impact of reaction temperature, concrete/siderite ratio and steam to carbon molar ratio on H-2 promotion had the following order: reaction temperature (43.1%), concrete/siderite ratio (30.2%) and steam to carbon molar ratio (26.7%). Additionally, the catalyst exhibited high activity when integrated into the freeboard zone of a bubbling fluidized bed gasifier. Compared to the reference condition, one observed significant impact at 700 C on the H-2:CO ratio (1.9 to 3.3), H-2 production (33.8 to 48.6 gH(2) & BULL;kg(dry,fuel)(-1)), carbon conversion efficiency (54.1 to 58.6%) and cold gas efficiency (55.0 to 60.9%). Though the catalyst exhibited resistance to sintering, post-mortem analysis suggests loss of active species after repeated cycles of regeneration due to thermal-induced stresses, which caused gradual decrease in activity.

Automated summary

This study proposes the use of granulated siderite/concrete-based catalysts for biomass steam gasification, aiming to enrich H-2 by water gas shift and CO2 adsorption. The impact of reaction temperature, concrete/siderite ratio, and steam to carbon molar ratio on H-2 promotion is investigated. The catalyst shows high activity when integrated into a bubbling fluidized bed gasifier. However, repeated cycles of regeneration result in a gradual decrease in activity.