CO2 gasification rate analysis of coal in molten blast furnace slag—For heat recovery from molten slag by using a chemical reaction

• The kinetic model of coal gasification using slag granules as heat carrier was obtained.
• The reaction model Am has the best fit on coal gasification using BF slag as heat carrier.
• The global rate equation that includes kinetic parameters was developed.
• The activation energy decreases with increasing coal/slag ratio.

The coal gasification rate of Datong coal in molten blast furnace slag using carbon dioxide as gasifying agent was studied at the temperature ranging from 1473 to 1723 K. The kinetic model was developed. The influence of reaction temperature and coal/slag mass ratio in the reaction rate was analyzed. The reaction rate has a strong dependence on reaction temperature and coal/slag ratio. The peak value of reaction rate increases firstly, and then levels off, or even decreases a little as temperature increases. Within the same reaction time, the carbon conversion and peak value of reaction rate increase with increasing coal/slag ratio. Molten BF slag is active catalyst for carbon gasification. The volume reaction model A1 has the best fit on coal gasification in molten BF slag. The kinetic parameters applicable to volume reaction model at high temperature with different coal/slag ratios were obtained. The value of intrinsic activation energy is between 50 kJ/mol and 90 kJ/mol. The global rate equation that includes these parameters was developed.Rate=ⅆxⅆt=k0iexp(−EaiRT)(1−x)