Variation of char reactivity during catalytic gasification with CO2 : comparison among catalytic gasification by ion-exchangeable Na, Ca, and Na/Ca mixture

Abstract

Reactivity is an important indicator to evaluate the gasification performance, and it is also the key to design and optimize the gasification process. The type and activity of the catalyst have great impacts on the gasification reactivity of the char. In this study, the catalytic behavior of ion-exchangeable Na and Ca during CO2 gasification process and the influence mechanism of ion-exchangeable Na and Ca on the gasification reactivity of coal char were researched. The results indicated that the reactivity of Ca-Char was greater than that of Na-Char. The inactivation of Ca was mainly due to the loss and the dispersion deterioration of Ca. The increase of CO2 concentration can not only significantly increase the catalytic activity of Na and Ca, but also enhance the sustainability of Na catalytic activity. The interaction between Na and Ca had inhibition effects on the reactivity of char during CO2 gasification. The higher the ratio of Ca-Char, the more significant the inhibition effects.