An Energy and Exergy Analysis of Biomass Gasification Integrated with a Char-Catalytic Tar Reforming System

Abstract

Adequate tar removal is a recurrent challenge for biomass gasification. Materials such as char and activated char are promising catalysts for tar reforming because of their activity, inexpensiveness, and constant production during gasification. Although the behavior of char and activated char as catalysts has been previously studied, an evaluation of the thermodynamic efficiencies of the tar reforming process using char as a catalyst still lacking. This work analyzes the performance of a two-stage system, where gasification is followed by tar reforming using char catalysts. For the study, a model based in a combination of equilibrium thermodynamics and chemical kinetics was developed. The first stage, where gasification occurs, was simulated with a thermodynamic equilibrium model. Gasification equilibrium models available in the literature only predict the fractions of H2, CO, CO2, and CH4; the model developed for this work also predicts the formation of a three-model tar with different characteristics (b...