Gasification Reactivity and Pore Structure Development: Effect of Intermittent Addition of Steam on Increasing Reactivity of PKS Biochar with CO2

Abstract

Intermittent addition of steam was employed to increase the gasification reactivity of palm kernel shell biochar with CO2. The reactivity and variations in pore structures were initially assessed during CO2 and H2O-assisted gasification of biochars in a tube furnace, followed by characterization using thermogravimetric and surface area analysis. A quadratic orthogonal rotation regression combination design was used to investigate the effects of intermittent H2O addition on the total reaction time (t100%) of CO2 gasification. The achieving results showed that the formation of micropores with sizes of 0.3 to 1.5 nm was favored by CO2 gasification, while the reactivity of biochar was highly correlated with the surface area of micropores of 0.93 to 1.47 nm. A pore expansion effect was the primary phenomenon observed during H2O gasification, while the reactivity of biochar with H2O was closely related to the surface area of pores with specific sizes. CO2 and H2O react with the biochar on separate active sites,...