Combustion kinetics and structural features of bituminous coal before and after modification process

Coal modification process is becoming popular to be used to upgrade coal quality. The upgraded coal (semi-coke) can be utilized in ironmaking process. Thermogravimetry and DAEM were used to analyze the combustion kinetics of bituminous coal before and after modification in this study. To understand the factors influencing the combustion process, various advanced techniques including X-ray diffraction analysis, Raman spectroscopy and Fourier transform infrared spectroscopy were adopted to investigate the structural features of the combusted samples. The results showed that the coal aromaticity increases significantly with the side-chains and chain length reduced, while the matrix structure transforms to graphite-like structure after the modification process. Those structural changes lead to the decrease in coal reactivity, thus weakening the coal combustion performance.