Study On The Relationship Of Products During Coal Pyrolysis

Pyrolysis have a important effects on the processes of gasification N liquefaction and combustion. The processes of pyrolysis can affect the physical and chemical character of char. The study on coal pyrolysis is one of most important parts in coal chemistry. We can understand chemical character of coal deeply and study its scientific classification by knowing coal structure. We can reasonablely and synthetically utilize it.Several Chinese coal samples have been studied in a novel reactor. The reactor has some features of fixed-bed reactor: the reactor allows the coal to be heated up rapidly as well as to be held for a pre-specified period of time at peak temperature. The yield and distribution of gas, liquid and solid products after pyrolysis are analyzed with modern analytic instruments,such as GC, Ultimate analysis, FTIR, XRD, element analyzer, and so on.It can be concluded form the findings of investigationgs that H/C atomic ratios in Char decreases with increasing peak temperature, while O/C atomic ratios in Char increases. H/C ratio and O/C ratio of chars can reflect the extent of pyrolysis of coal, so it is suggested that H/C ratio and O/C ratio of chars can be as practically useful index of extent of pyrolysis. H/C atomic ratios in Tar increases with increases peak temperature, while O/C atomic ratios in Tar decreases. The N/C atomic ratios in Tars and Chars have no obvious relationship with final temperature.The total gases yields increase with increasing peak temperature. During pyrolysis, the yield of HCN goes through a maximum with increasing rank, onthe contrary the yield of Ntb decrease with increasing rank, the yield of HCN and NHs are increasing in Both fast-heating and slow-heating with increasing temperature. The yield of COi is main products during primary pyrolysis.FTIR was applied for determination of aliphatic C-H and aromatic C-H of chars and Tars. From the FTIR spectrogram of Tar and Char in different temperature, we can draw a conclusion that fast-heating can produce more aromatic compounds than slow-heating at high temperature. Microcrystalline structure change of the chars from different heating condition was determined by XRD. During heat treatment, chars become progressively more ordered in structure by recombination and parallel orientation of aromatic nuclei which accompanies thermal destruction of peripheral groups. It was found that Average diameter of aromatic clusters (La) and an average height of crystalline (Lc) are seen to increase alone with the end pyrolysis temperature of chars.