Sewage sludge steam gasification over bimetallic mesoporous Al-MCM48 catalysts for efficient hydrogen generation

This study explored the potential of steam gasification of sewage sludge over different temperatures (non-cat-alytic) and bimetallic (Ni-Fe and Ni-Co) mesoporous Al-MCM48 (3-5% Al basis). The higher temperature (800 degrees C) resulted in higher gas yield (36.74 wt%) and syngas (H2 and CO) selectivity (35.30 vol% and 11.66 vol %). Moreover, catalytic approach displayed that the Al-MCM48 was effective support because the incorporation of nickel increased the efficiency of gasification reactions compared to HZSM-5 (30). It mainly comes from the presence of mesopores and higher surface area (710.05 m(2)/g) providing more reaction sites and higher stability (less coke formation). Furthermore, the addition of promoters such as Co and Fe allowed the formation of Ni-Fe and Ni-Co alloys, resulting in even higher gas yield and overall H-2 and CO selectivity due to the promotion of related reactions such as tar cracking, Boudouard, water gas shift and reforming and so on. Ni-Co alloy catalyst (10% Ni-5% Co/Al-MCM48) resulted in the highest H-2 (similar to 52 vol%) selectivity due to the enhanced Ni dispersion and synergy effect between Ni and Co. Moreover, the application of bi-metal alloy on Al-MCM48 showed no coke formation and significantly reduced CO2 and hydrocarbon selectivity in the product gas. Overall, this study presented a promising solution for sewage sludge disposal in terms of clean H-2 generation, reduction in CO2 and higher stability of metal based catalysts at the same time.

Automated summary

This study investigated the potential of steam gasification of sewage sludge using different temperatures and bimetallic catalysts. The higher temperature (800 degrees C) resulted in higher gas yield and syngas selectivity. The incorporation of nickel in the Al-MCM48 support improved gasification reactions compared to HZSM-5. The addition of promoters such as cobalt and iron allowed for the formation of Ni-Fe and Ni-Co alloys, leading to higher gas yield and overall H2 and CO selectivity.