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    30 January 2013, Volume 47 Issue 1 Previous Issue    Next Issue
    Applications of Computational Chemistry in Studying Gasification of Biomass
    STOGSDILL Michael;KEIPERT Kristopher;SONG Jie
    2013, 47 (1):  1-13.  doi: 10.3969/j.issn.1673-5854.2013.01.001
    Abstract ( 1130 )   PDF (1118KB) ( 980 )   Save
    Alternative fuels from renewable biomass have become a promising alternative to fossil fuels. However, it is a complicated reaction process, which includes pyrolysis and rate-determing gasification. In order to study the reaction mechanism, both experimental and theoretical approaches have to be applied. In this review, the computational theories applied in the gasification of biomass are summarized. The types, sizes, and electronic structure of theoretical models used are discussed. In addition, previous studies on adsorption, rearrangement, migration, and desorption during gasification are reviewed.
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    Combustion Characteristics of Wheat Straw and Its Briquette
    SUN Kang;JIANG Jian-chun;LU Xin-cheng;XIE Xin-ping;WANG Jin-biao
    2013, 47 (1):  14-18.  doi: 10.3969/j.issn.1673-5854.2013.01.002
    Abstract ( 1100 )   PDF (1353KB) ( 1168 )   Save
    TG-DTG thermal analysis technology was applied to study the combustion characteristic of wheat straw and wheat straw briquette at different heating rate (10, 20 and 30 ℃/min). Their Combustion characteristics were investigated, such as ignition temperature, burnout temperature, combustion parameters and combustion kinetics. The results showed that ignition temperature of wheat straw and wheat straw briquette were 250-260 ℃ and increased with the increase of heating rate. Combustion parameters of biomass are higher than coal. It indicated that the combustion performance of biomass was better than coal. From the kinetic analysis, combustion reaction of wheat straw and wheat straw briquette follows the basic equation of combustion kinetics and belong to first order reaction.
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    The Effect of Lignin in Straw on Hydrolysis Process by Extremely-low Acid
    WANG Cun-wen;DUAN Xiao-ling;WANG Wei-guo;LI Zi-hao;LV Ren-liang;QI Yuan-hang
    2013, 47 (1):  19-26.  doi: 10.3969/j.issn.1673-5854.2013.01.003
    Abstract ( 1024 )   PDF (1366KB) ( 1128 )   Save
    Taking rice straw (Hubei province) as the research object, the optimal condition of straw hydrolysis was investigated. The conversion rate of cellulose and hemicellulose, reducing sugar concentrations and yields, crystallinity of cellulose were determined after the extremely low acid (acid concentration below to 0.1 wt%) hydrolysis of 15 kinds of biomass straw under optimal hydrolysis conditions. The results indicated that the condition of the rotation speed of 500 r/min,the sulfuric acid volume of 45mL, the straw particle of 3 g, the hydrolysis temperature of 210 ℃, the hydrolysis time of 10 min and sulfuric acid concentration of 0.05% wt were determined as the optimal hydrolysis conditions. By studying the hydrolysis of the 15 kinds of biomass straw, it was found that with the lignin content increasing, cellulose and hemicellulose conversion rate decreased. This led to the decline of reducing sugar yield. By SEM, X-ray diffraction and composition analysis, the way that lignin affecting the lignocellulose hydrolysis was showed as follows: 1) the higher the lignin content, the higher the crystallinity of cellulose, the more difficult for de-crystallization of cellulose, thus the cellulose hydrolysis was confined; 2) the original lignin was not soluble in the reaction system and was relatively stable under acidic conditions. The lignin in rich lignin layer interfered with the reactant and product diffusion. It slowed down the hydrolysis rate of cellulose and hemicellulose in rich lignin layer; 3) the higher the lignin content, the thicker and the harder the rich lignin layer in lignocellulose, it was difficult for lignin to shed from solid surface and the hydrolysis rate decreased.
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    Purification, Characterization and Hydrolysis Mechanism of β-Xylosidase from Trichoderma reesei
    JIANG Xiao-hua;ZHU Jun-jun;YU Shi-yuan;YONG Qiang
    2013, 47 (1):  27-32.  doi: 10.3969/j.issn.1673-5854.2013.01.004
    Abstract ( 929 )   PDF (1125KB) ( 1336 )   Save
    Using ammonium sulfate precipitation, ultrafiltration desalination, ion-exchange and gel filtration column chromatography, a β-xylosidase with molecular weight of 110.8 ku and specific activity of 61.99 IU/mg was purified to homogeneity from culture xylanase solution of Trichoderma reesei Rut C-30. Results of enzymatic properties showed that the optimal reaction condition of the enzyme was: pH value of 3.5; reaction temperature of 60 ℃. The enzyme was stable below 60 ℃ and pH value ranges from 3.0 to 8.0. It had a Km value of 0.29 μmol/mL and Vmax value of 169.99 IU/mg by using p-nitrophenyl-β-D-xylopyranoside as the substrate. Results of enzymatic hydrolysis mechanism indicated that β-xylosidase released xylose from non-reducing ends of xylooligosaccharides by cutting off β-1,4-glycosidic bond. The optimum substrate of β-xylosidase was short-chain xylooligosaccharides. With chain length of xylooligosaccharides increased, the enzyme hydrolysis efficiency decreased gradually and xylan was hardly to be degraded.
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    Microwave-assisted Liquefaction of Rice Straw
    WANG Ning;;TIAN Chun-rong;LIN Xiao-yan;WANG Jian-hua;
    2013, 47 (1):  33-38.  doi: 10.3969/j.issn.1673-5854.2013.01.005
    Abstract ( 1115 )   PDF (1006KB) ( 1018 )   Save
    The rice straw was liquefied by microwave heating in the mixture of phenol and glycerol as the liquefying reagents with sulfuric acid catalytic. This paper discussed the effects of different factors on residue rate. The result showed that 7.17% of residue rate remained under the optimum conditions, i.e., microwave power of 500 W, the liquid-solid ratio of 7:1, the mass ratio of phenol and glycerol of 4:1, sulfuric acid amount of 5%, the temperature of 150 ℃ and reaction time 22.5 minutes. The results of GPC showed that with the extension of liquefied time, the relative molecular weight appears decreasing, but of the distributions, increased a bit. From the IR spectrum, it was concluded that the cellulose and hemicellulose are easier to be dissolved and the main ingredients of liquefaction residues are lignin and its derivatives.
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    Combustion Property of Bio-diesel Fuel Produced by Phacoemulsification
    WEI Xiao-li;WANG Shu-yang;GU Zhi-xin
    2013, 47 (1):  45-48.  doi: 10.3969/j.issn.1673-5854.2013.01.007
    Abstract ( 805 )   PDF (940KB) ( 1081 )   Save
    Using the variable frequency controlled waveform ultrasonic emulsification device, emulsion of 20% bio-oil with diesel by adding a little emulsifier(Span 80 and Tween 80) was used to produce the emulsified bio-diesel. Experiment showed that it can be used directly in diesel engine. The result of the experiment showed that the NOX emissions significantly reduced 50% lower than that by diesel. The smoke of B10, B15, B20 are all obviously lower than 0# diesel. The emission number for smoke "K" are all no more than 1 and far below the national standard (K<3).
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    Pyrolysis and Combustion Characteristics of Biomass Tobacco Stalk
    ZHONG Xian-fang;LIU Chun-bo;WANG Kun-miao;ZHANG Tao;HAN Jing-mei;CHEN Yong-kuan;WANG Ya-ming;MIAO Ming-ming;LIU Zhi-hua;
    2013, 47 (1):  39-44.  doi: 10.3969/j.issn.1673-5854.2013.01.006
    Abstract ( 1017 )   PDF (1007KB) ( 1397 )   Save
    In this paper combustion characteristics of tobacco stalk was studied. Simultaneous thermal analysis technology was used to analyze the influence of heating rate and particle diameter. Then combustibility index and kinetic energy were obtained. The effect of combustion characteristic index during pyrolysis or combustion reaction tobacco stem of heating rate on biomass of tobacco stem is Sn(20 K/min)>Sn(15 K/min)>Sn(10 K/min)>Sn(5 K/min).But the effect of with particle diameter 0.425 mm in pyrolysis is Sn(20 K/min)>Sn(15 K/min)>Sn(5 K/min)>Sn(10 K/min) and in combustion reaction is Sn(15 K/min)>Sn(20 K/min)>Sn(10 K/min)>Sn(5 K/min). At the same time, the effect of particle diameter on combustion characteristic index is Sn(0.180 mm)>Sn(0.250 mm)>Sn(0.425 mm).
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    Preparation and Certification of Reference Material of Gallic Acid
    WANG Yong-mei;WU Dong-mei;ZHANG Liang-liang;XU Man;CHEN Jia-hong
    2013, 47 (1):  49-53.  doi: 10.3969/j.issn.1673-5854.2013.01.008
    Abstract ( 870 )   PDF (869KB) ( 1271 )   Save
    Preparation, homogeneity, stability and certification of reference material of gallic acid were studied. Highly purified reference material of gallic acid was prepared from an industrial grade product of gallic acid by recrystallization. The chemical structural formula of gallic acid was identified by IR, NMR and thermogravimetric analysis. The content of gallic acid in reference material was measured by HPLC with area normalization method. The reference material of gallic acid passed the test of homogeneity, and it was stable within 15 months. According to certification of six laboratories, the standard value of gallic acid content was 99.96%±0.10%.
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    Current Research Status of Biomass Fluidized Pyrolysis Technology
    LI San-ping;WANG Shu-yang;SUN Xue;CAO You-wei
    2013, 47 (1):  54-60.  doi: 10.3969/j.issn.1673-5854.2013.01.009
    Abstract ( 959 )   PDF (810KB) ( 1334 )   Save
    This paper provides an updated review on the current research status of biomass pyrolysis influidized bed reactor and the development of pyrolysis reaction mathematical model. The dynamics is analyzed emphatically.
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    The Evaluation of the Impact of Chromated Copper Arsenate Treated Wood on the Environmental Safety
    YU Li-li;TANG Zhen-zhong;MA Xiao-jun;ZHU Li-zhi
    2013, 47 (1):  61-65.  doi: 10.3969/j.issn.1673-5854.2013.01.010
    Abstract ( 1342 )   PDF (771KB) ( 2151 )   Save
    This paper summarizes an overall introduction of the influence of chromated copper arsenate (CCA) treated wood which occupied a dominant position in the wood preservation market on the environment. It includes the influence of copper, arsenate, chromate and CCA treated wood in the service. This aims to promote the scientific production of the CCA treated wood and guarantee the service safety of the CCA treated wood.
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