Insight into coal catalytic gasification mechanism of Na or Ca using experiments combined with DFT calculations with carbon black as a novel coal model

Abstract

Research on the catalytic gasification reaction mechanism is helpful for innovation and for reforming catalytic gasification technology. Both Na and Ca catalysts have industrialization prospects because they effectively catalyze coal gasification. The mechanism is still not fully understood for these two kinds of catalysts because of the complexity and anisotropy of coal structure. In this paper, carbon black is used as a novel model to simulate the whole gasification process of coal, and the reaction pathway of Na or Ca catalytic gasification was obtained by combining experiments with DFT calculations. The results show that both Na and Ca play catalytic roles, but the catalytic effects and reaction paths of each are different. Ca must form the intermediate structure “C-O-Ca-C” with oxygen-containing structures in coal, and this changes the reaction path to reduce the activation energy. In contrast, the Na catalyst is a catalyzed gasification of coal with free Na2CO3 as an active center. These research results determine the reactive intermediates and reaction paths of the Ca and Na catalysis mechanisms and provide theoretical and technical support for the industrial production of Ca or Na catalysts.