Non-isothermal coal char gasification with CO2 in a micro fluidized bed reaction analyzer and a thermogravimetric analyzer

Abstract

The so-called micro fluidized bed reaction analyzer (MFBRA) and a thermogravimetric analyzer (TGA) were adopted to comparatively investigate the non-isothermal gasification of coal char with CO2. Experimental results demonstrated that heating rate obviously affected the coal char gasification reaction. Raising heating rate evidently increased the temperatures at the initiating reaction (Ti), the maximal reaction rate (Tm) and the finishing reaction (Tf). Nonetheless, it decreased the char conversion at a given reaction temperature and also the activation energy estimated by the single heating rate method. Comparing the data tested by TGA and MFBRA under the same heating rate clarified that the temperatures of Ti, Tm, and Tf were all relatively lower for MFBRA. The difference for such characteristic reaction temperatures between TGA and MFBRA increased with raising the heating rate. The measurement in MFBRA also led to the higher activation energy estimated according to both the single heating rate and the combination heating rate methods. Perhaps all these results are attributed to the lower limitation from heat and transfer including gas diffusion in MFBRA than in TGA.