Co-combustion characteristics and CO2 emissions of low-calorific multi-fuels by TG-FTIR analysis

Abstract

In this study, the combustion performance and CO2 emission of coal slime (CS), coal gangue (CG) and raw coal (RC) mixtures were systematically investigated by TG-FTIR. The interaction and kinetics during the co-combustion process were analyzed. The results show that the co-combustion avoids the drawbacks of mono-combustion and is conducive to reduce the emission of CO2. The effects of proportion in the blends, O2 concentration and heating rate were discussed and the optimum combustion parameters are obtained by the orthogonal experiments. As the proportion of CS increases in the mixtures, the average comprehensive combustion characteristic index (Save) increases by 2.1 times. Synergistic interaction is detected between CS, CG and RC during co-combustion. Moreover, the CO2 absorption peak of CS is much higher than that of CG and RC. By mixing method, the experimental CO2 integral values are about 50% lower than anticipated. In order to get better combustion characteristics and lower CO2 emission, the potential global optimum blending ratio of CS is 80%, O2 concentration and heating rate for co-combustion of the mixtures are 40% and 30 °C/min, respectively. This study provides valuable information for the proportion selection and optimization of co-combustion system of coal blends in the CFB.