The steam gasification of coal with molten blast furnace slag as heat carrier and catalyst: Kinetic study

Abstract

In this study, we carried out a kinetic investigation to analyze the steam gasification of FS (Fu Shun) coal. The effect of reaction temperature (1573 K–1673 K) was studied, and the coal/slag ratios were in the range of 1:0–1:2. The reaction temperature and coal/slag ratio affected the carbon conversion and reactivity index of FS coal gasification. With reaction temperature increasing, the time for carbon conversion completing decreased. But the effect of temperature was non-significant, when it was above 1623 K. The reactivity index of coal at 1673 K was about 1.6 times faster than that at 1573 K, when the coal/slag ratio was 1:0. The BFS (blast furnace slag) acted as not only a heat carrier but also an effective catalyst in steam gasification. Compared with the steam gasification of “pure” FS coal, both carbon conversion and reactivity index of gasification were enhanced by BFS. Meanwhile, the Diffusion model (D1 model) and Shrinking core model (R2 model) were proved as the most appropriate model to describe the steam gasification without and with BFS as heat carrier, respectively. The kinetic parameters applicable to the established model with different coal/slag ratios were obtained. Under these conditions, the valid range of activation energy for gasification reaction was 20 kJ·mol−1–64 kJ·mol−1.