Effect of chemical fractionation treatment on structure and characteristics of pyrolysis products of Xinjiang long flame coal

The Xinjiang region is one of the most important energy bases in China. A demineralized coal treated by the chemical fractionation method will provide a promising approach to evaluate the inherent minerals catalytic performance in pyrolysis, especially which contains abundant alkali metals. The effect of ash removal on the physicochemical structure and pyrolysis characteristics of coal sample were explored, and the acetic acid, hydrochloric acid and hydrofluoric acid were applied to carry out the ash removal. Related characterization instruments were adopted to investigate physicochemical structure changes of coal sample treated by different acid, as well as the composition of pyrolysis products. Here, we show the ash removal plays a leading role in improving volatile yield, the unsaturated side chain in the aliphatic structure of demineralized coal fracture. The peak intensity of methylene and methyl weaken, which leads to the weight loss of HM2R is higher than the other three demineralized coals at the temperature range of 180-370 degrees C. With the deepening of ash removal, the yield of gas products and tar increase and the char yield decreases, and the relative content of benzene, phenol and polycyclic aromatic hydrocarbons in tar decrease and the content of aliphatic hydrocarbons increases. When the pyrolysis temperature reaches 700 degrees C, the H-2 concentration reaches the maximum value and it shown as follows: HM2F > HM2H > HM2A > HM2R. It is proved that the inherent minerals have a catalytic cracking effect on the heavy component in tar.