| Energy sources and industrial raw in chemical industry are mostly originated from fossil resources. Many environmental problems, such as the inevitable increasing of the CO2 net concentration in atmosphere, result from the use of fossil resources. And more, fossil resources are reducing rapidly. So it is necessary to exploit new renewable energy sources and raw materials for chemical industry. Biomass includes fuel forest, economic forest, commercial forest, crops straw, forestry process residues and all kinds of organic rubbish etc. It is the only source of raw materials that is renewable and can be converted into liquid fuel and other products directly. In the present work, pubescens which is special to Sichuan province is selected as raw materials to produce liquid chemicals. The main chemical components of pubescens with different growth ages are analyzed, and the influences of pyrolysis parameters on the products yields, the production of gas and the distribution of liquid products under non-catalytic or catalytic conditions are studied as well. The contents of cellulose, hemi-cellulose and lignin of pubescens with different growth ages for different sections are determined chemically. The pubescens powder is pyrolyzed in nitrogen gas flow with or without catalysts. The catalysts used are a series of NiO/γ-Al2O3 catalyst with different Ni contents (5%, 10%, 15%) and three kinds of zeolite catalysts (HZSM-5,Hβ,NaY) with different quality ratios of catalyst to pubescens powder. After pyrolysis, residues are weighed. Liquids are collected, weighed and analyzed with Agilent5973N GC/MS, while gas products are determined by gas chromatography on line. It is found that no significant changes in chemical components such as cellulose, hemi-cellulose and lignin, are observed among annual, biennial and perennial pubescens. It is indicated that pubescens can be ripe rapidly within one year. So it can well meet the demand for sustainable development as a renewable resource. For the direct pyrolysis of pubescens in the absence of catalyst, it is also found that the content of liquid products increase with increasing the pyrolysis temperature, and reach the maximum, 37wt% at 550℃, then decrease. The content of gas products are nearly the same at 300~500℃, and reach the minimum at 550℃, then increase at 600~700℃. The major components of liquid products are acetic acid, 2,6-dimethoxyphenol, and 2,3-dihydrobenzofuran, etc. The use of γ-Al2O3 or a series of NiO/γ-Al2O3 catalysts has a great influence on the content of liquid and gas products at different pyrolysis temperatures. The presence of the catalyst with 5% Ni content leads to the lowest output of liquid, but it does favor to the formation of gas. The catalytic gas products contents are much higher than non-catalytic ones. H2,CH4,CO and CO2 are the main components of pyroysis gas products. The higher content of Ni in the catalyst leads to a higher H2 content. Catalyst containing 10% Ni has the best selectivity to liquid products and the kinds of the liquid products are significantly reduced at 600℃. The presence of zeolite catalysts causes a significant rise in the liquid content. With the ratio of catalyst to pubescens powder increases from 1:5, 2:5, 1:2, 3:5, 4:5, 1:1 to 2:1, the liquid content increases, and the species of compounds in the liquid product decreases. NaY has the best selectivity to liquid yield and to acetic acid among the three kinds of catalysts. The number of compounds in the presence of NaY is less than the others. Acetic acid is the main component in the liquid products. Different catalysts have different selectivity to certain products. Under the catalysis of HZSM-5, a little naphthalene and its methyl and dimethyl substituent could be observed, while triethylamine only appear under the catalysis of Hβ. In conclusion, results suggest that pyrolysis of pubescens can be used toproduce chemicals and energy materials. The choose of specific catalysts according to the kinds of biomass and the needs of chemicals, as well as the pyrolysis conditions, could enhance heat efficiency, and provide more useful liquids.
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