Development of a Ba–Ni/SiO2 Catalyst for the Simultaneous Decomposition of Ammonia and Naphthalene/Benzene Formed as Byproducts in the Steam Gasification of Woody Biomass

Abstract

We propose a consecutive process for the decomposition and/or cleanup of the byproducts formed by the steam gasification of woody biomass, and in this study, we report on the development of a Ni-based catalyst for the simultaneous decomposition of tars and ammonia. The effects of the support and additive metal on the catalytic performance of Ni-based catalysts in the steam reforming of model tar compounds were first investigated, leading to the selection of SiO2 and Ba as the optimal support and additive metal, respectively. The optimal Ba/Ni molar ratio was determined to be 0.033, and Ba–Ni/SiO2 (Ba/Ni = 0.033) was then applied to the steam reforming of model tar compounds in the presence of ammonia (0.05 mol%) at 923–973 K. Catalyst deactivation was observed at 923 K in the presence of ammonia, whereas the catalyst retained its activity at 973 K irrespective of the presence of ammonia. In cycle tests involving the simultaneous decomposition of naphthalene/benzene and ammonia followed by oxygen regeneration treatment, Ba–Ni/SiO2 exhibited stable performance for at least three cycles. It was concluded that this catalyst is a promising candidate for the simultaneous decomposition of tars and ammonia.

Keywords

• Tars
• Ammonia
• Simultaneous decomposition
• Ba–Ni/SiO2 catalyst
• Steam gasification