The importance of inherent inorganics and the surface area of wood char for its gasification reactivity and catalytic activity towards toluene conversion

Abstract

Gasification char is an effective catalyst for tar reforming because of the abundance of surface active sites, which are available for heterogeneous conversion of hydrocarbons and interactions with the reforming agents. This paper focuses on the importance of certain char properties for the gasification and catalytic reforming. Specifically, the gasification reactivity of spruce char is examined, along with its performance as a catalyst for toluene conversion. The material used for this work was produced via gasification of spruce wood chips in the pilot TwoStage Viking plant (Technical University of Denmark, Risø). To obtain a set of samples with varied surface area characteristics and inorganic content, three pre-treatments were applied to samples of this char: acid washing, steam activation, and high-temperature treatment. The gasification and catalytic experiments performed with the untreated and modified materials revealed that the reactivity of the char during gasification in CO2 depends mostly on the metal content in the sample, whereas the conversion of toluene was insensitive to the char inorganic content, but strongly correlated with the surface area available for heterogeneous reactions with toluene.