Gasification reactivity of Hami coal liquefaction residue char

Liquefaction residue is an important by-product of the coal liquefaction process and its application as gasifi- cation feedstock would help to improve the comprehensive utilization efficiency of coal resource. In this study,the rapid pyrolysis chars of Hami Naomaohu long flame coal and its liquefaction residue were prepared at different pyrolysis tem- peratures (1 000 ℃ and 1 300 ℃ ) using a high-frequence furnace. The gasification reactivity of chars was investiga- ted using a Thermogravimetric Analyzer (TGA) at different gasification temperatures (1 000 ℃ ,1 100 ℃ ,1 200 ℃and 1 300 ℃ ). In addition, Scanning Electron Microscopy, Physisorption Analyzer and Laser Raman Spectrometer were used to systematically characterize the physicochemical properties (pore and carbon structure) of samples so as to correlate the char gasification reactivity. The results show that the gasification reactivity of coal char and the lique- faction residue char was affected by gasification temperature,pore structure and carbon structure. The gasification reac- tivity of coal char was higher than that of liquefaction residue char at the same pyrolysis and gasification temperature, which was mainly due to the difference in physicochemical properties between coal char and liquefaction residue char. The former showed the more developed pore structure,the higher order degree of carbon structure and the greater a- mount of amorphous carbon structure than the later. The reactivity index of coal char and liquefaction residue char in- creased from 0. 43 and 0. 38 to 0. 81 and 0. 79,respectively,and the reactivity index ratio increased from 0. 88 to 0. 98 as the gasification temperature increased from 1 000 ℃ to 1 300 ℃ ,indicating that the increase of the gasification tem- perature can promote the gasification reaction,but the influences of pore structure and carbon structure on the char gasification reactivity was weakened. Specifically for the gasification temperature of 1 300 ℃ ,the temperature becomes the main factor affecting the gasification reactivity and the gasification reactivity of the liquefaction residue char was closed to that of coal char,demonstrating that the liquefaction residue could be utilized as a raw material in entrained- flow gasification based on the viewpoint of gasification reactivity.