Co-gasification of coal and biomass in a fixed bed reactor with separate and mixed bed configurations

Abstract

This study inspects the occurrence of synergy in the co-gasification of coal and biomass in a fixed bed reactor. Two separate and a pre-mixed bed configurations with a congruent sample mass are designed for comparative study. The intimate contact between bio-ash and coal char grains is a prerequisite for the occurrence of the synergy effect in the co-gasification of coal and biomass. The separate bed configurations generally form either a coal-char/bio-ash or a bio-ash/coal-ash interface, whereas the pre-mixed bed configuration produces well-dispersed bio-ashes that come into close contact with coal char grains. As a result, a stronger synergy effect occurs in the mixed bed configuration rather than in the separate configuration. A novel method is explored to collect and determine the heavy tar and water yields generated during the initial pyrolysis step. Results show that bio-char bed has better tar cracking performance than coal char bed.