Effect of fractional extraction on the combustion characteristics of four Chinese coals

The effect of the fractional extraction with petroleum ether (PE), carbon disulfide (CS2), methanol, acetone, and tetrahydrofuran (THF) on the combustion characteristics of four Chinese coals were investigated using thermogravimetric analysis (TGA). The maximum extraction yield of 6.9% from Yujialiang coal (YJLC) and the minimum extraction yield of 2.6% from Hulunbuir coal (HLBC) were obtained. Although the difference of extraction yield is obvious, the Fourier transform infrared spectroscopy (FTIR) results imply that the extracts have analogous functional groups, and aromatics are dominations in extractable components. Compared with subbituminous coals, the HLBC is more prone to ignite according to the ignition temperature from the TGA results. The pretreatment of extraction changes the combustion behaviors and increases the burning temperature.