The Morphologic Change Of Raw Coal And Char In The Process Of Pyrolysis And Gasification

In this paper, the morphology change of coal in the process of fast and slow pyrolysis, morphology change of char in the process of gasification and the gasification characteristics of char were studied. Experiment results indicated that XJ Houxia and SF coal were pyrolyzed in drop tube furnace, as the pyrolysis temperature raises, the trend of XJ Houxia char is monotonous, and the trend of SF char is decreasing-increasing-decreasing. Fragmentation, swelling and agglomeration occur in the process of XJ Houxia coal pyrolysis. In the process of SF coal pyrolysis just happen fragmentation and swelling. Due to the formation of C-O key, the C-O key value of SF char is bigger than SF coal.XJ houxia and SF coal were pyrolyzed in the high frequency furnace. As the pyrolysis temperature raises, the ratio of carbon-hydrogen and the release of the volatile raise slightly. The fragments are stripped from outer sphere of XJ houxia and SF coal, and obvious in 1300℃. The infrared spectrum shows that except for C-O key, the rest of function groups are largely decomposed in pyrolysis.Six coals including NM, YN, YL, SF, GZ, SX were pyrolyzed in thermogravimetry analyzer, XJ Houxia fast pyrolysis char of different sizes and six slow pyrolysis chars of different sizes were gasified in thermogravimetry analyzer, the smaller the particle size is, the faster the rate of coal pyrolysis gas release, the younger the coal is, the smaller the pyrolysis temperature of maximum weight loss rate is. The fragmentation occurs in the gasification process of fast pyrolysis char, however not happens in the gasification process of slow pyrolysis char. The gasification data of six slow pyrolysis char is fitted well by the random pore model. The order of constant k is YN, NM, SF, YL, SX, GZ.