| Abstract Scope |
To investigate the regulatory effect of thermal dissolution modification on the gasification reaction characteristics of coal char, this study took four types of raw coal (KL, GD, XB, ZS) and their corresponding thermal dissolution coal (TDC) as research objects. Carbonization treatment was conducted in a high-temperature tube furnace under the conditions of 1225 K, a heating rate of 10 K/min, a holding time of 90 min, and N₂ protection. Combined with an HCT-4 microcomputer differential thermal balance (equipped with a steam generator), the CO₂ and steam gasification reactivity of the samples was studied. Characteristic parameters including the initial reaction temperature (Ti), temperature corresponding to the maximum reaction rate (Tm), final reaction temperature (Tb), and maximum reaction rate (dx/dtmax) were analyzed, and the catalytic effect of minerals was evaluated using the basicity index (A).The results showed that after thermal dissolution modification, the CO₂ and steam gasification reactivity of the four types of coal char decreased significantly, which was manifested as a right shift of the weight loss curve, an increase in Ti and Tm, and a decrease in dx/dtmax (except for a slight increase in dx/dtmax of ZS during steam gasification). The basicity indices of raw XB and ZS coal (14.9 and 15.6, respectively) were significantly higher than those of raw KL and GD coal (0.658 and 0.544, respectively), and their TDC exhibited more obvious reaction lag (Ti increased by over 100 K, while Ti of KL and GD TDC only increased by approximately 60 K). This confirms that the catalytic effect of minerals (such as Fe₂O₃ and CaO) is a key factor affecting gasification reactivity. Thermal dissolution modification can regulate the gasification reactivity of coal char by removing ash, which provides a reference for the optimization of coal char performance in blast furnace ironmaking and gasification processes. |