Physico-chemical structure evolution characteristics of coal char during gasification in the presence of iron-based waste catalyst

Abstract The present study aims to explore the physico-chemical structure evolution characteristic during Yangchangwan bituminous coal (YCW) gasification in the presence of iron-based waste catalyst (IWC). The catalytic gasification reactivity of YCW was measured by thermogravimetric analyzer. Scanning electron microscope–energy dispersive system, nitrogen adsorption analyzer and laser Raman spectroscopy were employed to analyze the char physico-chemical properties. The results show that the optimal IWC loading ratio was 5 wt% at 1000 °C. The distribution of IWC on char was uneven and Fe catalyst concentrated on the surface of some chars. The specific surface area of YCW gasified semi-char decreased significantly with the increase of gasification time. i.e., the specific surface area reduced from 382 m2/g (0 min) to 192 m2/g (3 min), meanwhile, the number of micropores and mesopores decreased sharply at the late gasification stage. The carbon microcrystalline structure of YCW gasified semi-char was gradually destroyed with the increase of gasification time, and the microcrystalline structure with small size was gradually generated, resulting in the decreasing order degree of carbon microcrystalline structure. IWC can catalyze YCW gasification which could provide theoretical guidance for industrial solid waste recycling.