Dynamic characteristics of Shenmu char at the late stage of reaction with CO2 and steam.

A comparative study on the reactivity of Shenmu char with CO2 and steam was conducted at the temperatures from 900 °C to 1 050 °C using isothermal thermogravimetric analysis method. To better understand the reaction activity of residual carbon, the homogeneous model, the shrinking un-reacted core model, the integrated model and the modification volumetric model were applied to correlate the relationship between reaction rate and carbon conversion at the late gasification stage. The results show that both the integrated model and the modification volumetric model have a better fitting accuracy. The fitting accuracies of the homogeneous model and the shrinking un-reacted core model change with the gasification temperatures and the agents. At the late stage, the ranges of the apparent activation energy of Shenmu char in the atmosphere of CO2 and steam are 200. 65-231.00 kJ/mol and 105.48-169. 10 k J/tool, respectively. The apparent activation energy calculated with the modification volumetric model is approximately 36 kJ/mol higher at the late stage than that at the early and middle stages. Shenmu coal char gasification was under chemical reaction control at the late stage within the experimental temperature range. [ABSTRACT FROM AUTHOR]