STUDY OF THE COMBUSTION MECHANISM OF OIL SHALE SEMI-COKE WITH RICE STRAW BASED ON GAUSSIAN MULTI-PEAK FITTING AND PEAK-TO-PEAK METHODS

Abstract

In this research, a series of experiments on combustion of Huadian oil shale semi-coke and rice straw as well as their mixture were conducted at different heating rates (10, 20, 50 and 80 °C/min) under atmospheric pressure, using a Perkin Elmer thermogravimetric analyzer. Combustion characteristics were investigated at different proportions of materials (L1, L2, L3, L4 and L5) and at different heating rates. The results revealed that the point of ignition and burnout shifted to lower temperature with increasing rice straw proportion in the mixture. In the combustion process, the inter- action between the mixture components mainly occurred in the temperature range of 400 to 600 °C. It was found that in this stage the reaction of bimodal components of semi-coke and rice straw took place. Besides, using the Gaussian multi-peak fitting method it was established that the derivative mass loss (DTG) curves displayed an overlapping peak, which consisted of three sub-peaks corresponding to the components of the blend. Moreover, based on the three sub-peaks, kinetic parameters and feature values were found employing the peak-to-peak method. The results showed that the reaction order of various sub-peaks for samples L1, L2, L3 and L4 was 1.17 to 2.27. The activation energies of sub-peaks were determined to be 21.89- 99.79 KJ/mol throughout the analysis of the combustion mechanism. It was concluded that the model can be applied to determining combustion charac- teristics.