Investigation on carbide slag catalytic effect of Mongolian bituminous coal steam gasification process

Abstract

Carbide slag may pollute the environment because it is difficult to handle. In this paper, carbide slag without pretreatment served as the new source of calcium and was added to bituminous coal for gasification experiments to realize waste utilization. The gasification experiment after adding carbide slag to bituminous coal enhances H2 production, which reduced the activation energy of the gasification reaction. The results show that the catalytic effect on steam gasification was evident when the carbide slag was added to Mongolian bituminous coal. The coal char at reaction temperature was prepared and characterized by X-ray diffraction (XRD), Raman, Scanning electron microscope (SEM), Transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and FT-IR spectroscopy. The carbon structure evolution and calcium structure changes of coal char under reaction temperature were studied, and the influence of coal char structure changes on gasification performance was analyzed. The results show that in the coal char added with carbide slag, the oxygen-containing functional groups generated by the polycondensation reaction interacted with calcium to form a calcium-oxygen-carbon complex. The existence of this structure not only leads to the highly uniform dispersion of CaO in the char but also hinders the graphitization process of the char. Highly dispersed CaO and disordered carbon structure significantly improved the reactivity of bituminous coal steam gasification. Si and Al in the bituminous coal affected the dispersion of Ca during steam gasification.