Detailed gasification process of woody biomass-derived char with H2O and CO2 gasifying agents

Abstract

To effectively utilize renewable biomass resources, gasification technology is being actively developed. Many studies have been performed regarding the gasification of biomass-derived char (i.e., biochar), where the gasification rate varies greatly with experimental device and biomass type, even when the same gasification temperature is used. In addition, the pore development mechanism during gasification i.e., the relation between the gasification reaction rate and interface area, has been rarely studied. Herein, the gasification rate of wooden biochar with H2O and CO2 gasifying agents using same experimental apparatus and char samples were investigated. The development of micro- and mesopores in the biochar during gasification with H2O and CO2 agents was examined in detail. The results showed that (1) gasification rate constant of biochar was approximately 3–10 times higher under H2O gasifying agent than under CO2 agent at 1073–1273 K; (2) this study reported the most typical values of frequency factor A and activation energy E on Arrhenius plot at high temperature region; and (3) the specific surface area of the micro and mesopores increased with proceeding H2O and CO2 gasification, and the reaction rate is proportional to the interface area during the gasification process.

Keywords

• biomass
• gasification rate
• bet specific surface area
• pore structure
• adsorption
• surface reaction
• char
• pyrolysis