Study On Catalytic Pyrolysis Of Shihezi Bituminous Coal Under Pyrolysis Gas

Xinjiang is rich in coal resources, ranking the first in China. Xinjiang area carryout the new coal chemical industry will be rapid economic development boosterwestern, actively carry out grading transformation and utilization of clean coal, has avery important practical significance on the development of Western China andenvironmental protection.In this paper, six catalysts, Co/MgO、Co/Al2O3、Fe/MgO、Fe/Al2O3、Ni/MgOand Ni/Al2O3, were prepared by incipient impregnation method. Catalytic pyrolysis ofShihezi bituminous coal was carried out in a fixed-bed reactor under pyrolysis gasatmosphere. The effect of pyrolysis gas on the catalytic pyrolysis behaviors wasstudied by comparative analyses of the tar yield, char yield, the proportion of light oiland asphaltene and the group composition with N2atmosphere pyrolysis. The resultindicates that the three catalysts have catalytication to pyrolysis of Shihezi bituminouscoal, especially the catalysts of Ni/MgO can improve the tar yield obviously. The taryield reach to7.33%under conditions of gas flow rate of400mL/min,550℃andcatalysts of Ni/MgO. Compared with N2pyrolysis and pyrolysis gas pyrolysis undercomparable conditions, the tar yield increased78%and42%respectively. And thecatalysts of Co/MgO can improve the light oil yield obviously. The results suggestthat the influence of pyrolysis gas on the catalytic pyrolysis behaviors wassignificantly which benefit to inhibit the polycondensation reaction, increase the taryield and improve its quality. Co/Al2O3、Fe/MgO、Fe/Al2O3、Ni/MgO and Ni/Al2O3has lower tar yield and higher carbon deposition on the catalyst.The effect of process conditions on the catalytic pyrolysis behaviors underpyrolysis gas atmosphere was studied. The result shows that The tar yield increaseswith increasing PG flow rate and reaches the maximum7.33wt.%at400mL/min.Method for loading the catalyst, the above help to improve the yield of coal tar; mixedin coal and can increase the proportion of light oil, but reduces the tar yield; in thelower-level the tar can crack on the catalysts and is not conducive to the generation oftar. Reduction temperatures of Ni/MgO catalysts is not the main factor of improvingtar yield. Four kinds of gas in the pyrolysis gas promote coal pyrolysis, and theexistence of the reforming reaction between each other.Through the separation of the group composition by the column chromatography,the light oil has been divided into two different groups including aliphatic series,aliphatic series (aromatic series and polar fractions). Aliphatic series proportion 20%～33%and non-aliphatic series proportion67%～80%. The catalysts can reducethe aliphatic series yield, especially the Fe catalysts. Though the GC/MS analysis, weknow mostly of aliphatic series is alkane and more than94%of non-aliphatic series isaromatic series.