Comparative Study Of Solvent Extraction And Low Temperature Pyrolysis Of Huating Coal

Coal as an important non-renewable resources, its reasonable and effective application isparticularly important. Industrial chemicals extracted from coal is one of the effective methodof comprehensive utilization of coal. But, the efficient utilization of coal and the developmentof clean technologies rely on the studies of coal microscopic composition and structure. Thesolvent extracting coal is one of the important methods of investigating chemical structure ofcoal.In this paper, the molecular structure of Huating coal and the sources of coal tar arefurther explored by means of comparative study on microwave assisted extraction of coal andlow temperature pyrolysis. Furthermore, effects of particle size, pyrolysis temperature,reaction time and catalyst on tar during coal pyrolysis are investigated to improve the yield oftar. Granularity, TG and FT-IR analysis are used for raw coal, residual coal and char of rawcoal and residual coal to compare the properties between raw coal and residual coal before andafter the pyrolysis； Composition and distribution of tar are analyzed by GC-MS analysis.Finally, suggestions of comprehensive utilization of coal are raised.In this paper, composition and property of microwave assisted solvent extraction andlow-temperature are compared. Results indicated that volatile content of Huating coal is42.97%; tar yield is4.75%; total extraction rate of six-step extraction is30.76%; For residualcoal of extraction, tar yield is0.50%, gas yield is5.18%, sum of total extraction rate ofsix-step extraction, tar yield and gas yield is36.44%, which is close to the volatile content ofraw coal. Content of gases such as C2H2, C2H4, C3H6, C4H10, H2, CH4in gas production ofpyrolysis of residues coal for the extraction is less than that of the raw coal, which illustratedthat both extraction of solvent extraction and tar of low-temperature pyrolysis are from thevolatile matter of Huating coal; For Huating coal that particle size ranges from120to160mesh, tar yield of pyrolysis is the highest under the condition of final temperature of610℃and reaction time of30min，and tar yield is8.30%. Under the same reaction condition, tar yield of Fe2O3catalytic pyrolysis is11.92%, and tar yield is13.01%for MoS2. Compared withraw coal, amount of mesoporous is significantly reduced and aromaticity is decreased forresidual coal of extraction, but N content is increased. The bigger of the pore in coal, the morebenefit to separate out the tar produced during pyrolysis. For residual coal after extraction, thearomatic degree for char char is increased. Methylene is not found in the tar of raw coal andresidual coal. Fe2O3can promote the formation of aromatic hydrocarbons such as benzene,phenol and naphthalene, in which yield of benzene, phenol and naphthalene is respectivelyincreased by7.97%,8.17%and1.35%, reaching to10.04%,24.15%and15.23%respectively.