Transformation behavior of potassium-containing minerals during co-gasification of petroleum coke and biomass

Abstract

Interactions between alkali metals in biomass and silicon and aluminum minerals in petroleum coke (PC) are closely related to the gasification reactivity and the deactivation of active K-catalyst during co-gasification. This study comprehensively investigated the evolution of K-containing minerals and their impact on the gasification reactivity and ash fusion characteristics during the co-gasification of PC and wheat straw (WS). The results showed that the addition of WS improved the gasification reactivity of PC, but only up to a certain point due to the K-containing mineral evolutions at high temperatures. Adding WS below 20 wt% resulted in the deactivation of K and the formation of inert kaliophilite and nepheline. However, when WS addition exceeded 20 wt%, a substantial amount of K acted as an active K-catalyst, significantly increasing gasification reactivity. The shrinking core model was found to be more appropriate than the homogeneous model when considering gasification kinetics during co-gasification.