96/05925 The role of carbonization in the evolution of coal char gasification reactivity

Abstract

The relevance of thermal annealing of coals to the physico-chemical properties of the residual coke or char has been often addressed in the literature. The emphasis is most frequently on the structural modifications induced by carbonization in relation to mechanical properties. More limited and sparse information is available on the influence of the severity of pyrolysis and of carbonization conditions on the reactivity of chars in the context of coal gasification. Thermal annealing affects char gasification along two paths: on one side it induces reordering of the turbostratic structure of coals, on the other side it affects the activity and distribution of mineral inclusions. Both processes lead to char deactivation, their relative importance being dependent on the nature of the parent coal. In this paper the effect of thermal annealing on the reactivity of char from bituminous coal in carbon dioxide atmospheres is investigated. Experimental results are interpreted in the light of a simple reaction model.