Exergy analysis on the steam gasification of various biomass at the dual fluidized bed gasifier

Gasification of biomass is an attractive technology for combined heat with power production as well as for synthesis processes such as production of liquid and gaseous biofuels. Dual fluidized bed (DFB) technology offers the advantage of a nearly nitrogen-free product gas mainly consisting of H2, CO, CO2 and CH4. Based on experimental data from literature, exergy analyses was performed for the DFB steam gasification process in this paper. The influence of operating parameters such as steam-to-fuel ratio, gasification temperature, catalyst on the exergy efficiency has been investigated .The results show that the higher gasification temperature results in significantly higher heat value of product gas. In addition, the exergy efficiencies are observed to be higher when steam-to-fuel ratio is lower.With the increase of the bed material content in the catalysts, the exergy efficiency value will also become higher. And different kinds of catalysts always have different exergy ficiency values. The silica sand is suitable bed material for DFB gasifier