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Table of Content
05 November 2014, Volume 33 Issue 11
    Preparation and chemical application of ionic liquids
    JIANG Pingping,LI Xiaoting,LENG Yan,DONG Yuming,ZHANG Pingbo
    2014, 33(11):  2815-2828. 
    Abstract ( 278 )  
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    The development stage of ionic liquids and its excellent properties,such as negligible vapor pressure,good solubility and thermal stability,high ionic conductivity and wide electrochemical stability window are reviewed. The type,structure-activity relationship and preparation methods of ionic liquids are summarized and application in chemical extraction as solvent and application in organic synthesis as catalyst are also presented,including the Friedel-Crafts reaction,Diels-Alder reaction,C-C coupling reaction,esterification and epoxidation. Compared with the traditional catalyst,the effects on different catalytic reactions of ionic liquids with different types are highlighted. The trend of ionic liquids in energy conservation and emission reduction and highly efficient heterogeneous catalytic reaction is discussed.
    Phase distribution pattern and mechanism of bubbly flow in pipes
    PANG Mingjun1,2,XU Yidan1,WEI Jinjia2
    2014, 33(11):  2829-2842. 
    Abstract ( 164 )  
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    Phase distribution pattern and mechanism of bubbly flow in pipes are reviewed. Depending on flow condition,phase distribution shows the wall-peaked profile,the intermediate-peaked profile,the core-peaked profile,the transition profile,and the flat profile for the upward flow in a small diameter pipe,whereas it shows the off-center-peaked profile,the bell-typed profile,and the core-peaked profile for the downward flow. For the flow in the pipe with a large diameter,phase distribution shows only the wall-peaked and the core-peaked profile,independent of flow direction. Additional phase distribution patterns,such as the double-peaked and the double-saddle profile,are also reported. The main factors affecting phase distribution are bubble diameter,pipe diameter,gas/liquid velocity,injection place,injection method,and gravity level. Of these factors,bubble diameter is the most important for phase distribution. A general mechanism,which can be used to explain all phase distribution phenomena,has still not been developed up to now. Part of physical phenomena can be qualitatively explained by lift force in combination with turbulence dispersion force,wall repulsion force,or others. Future studies should focus on investigating the interphase force model,the bubble transport mechanism by turbulence coherent structures,etc.
    Thermodynamic analysis on the process of S Zorb reaction adsorption desulfurization
    YU He1,ZHAO Jigang1,HOU Xiaoming1,2,SHEN Benxian1
    2014, 33(11):  2843-2847. 
    Abstract ( 204 )  
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    S Zorb process can reduce the sulfur content in gasoline to less than 10μg/g. But because of the addition of H2,not only the desulfurization reactions of sulfur compounds occur on the surface of the adsorption,but also the hydrogenation reactions of olefins and aromatics and the hydroisomerization reactions are associated during S Zorb reaction adsorption desulfurization. The thermodynamic properties of these reactions were analyzed in this paper,including reaction enthalpy,Gibbs free energy,equilibrium constant and thermodynamic conversion. The results show that all these typical reactions are exothermic and the order of heat release is as follows:aromatic hydrogenation>thiophene desulfurization>olefin hydrogenation>the generation of mercaptan>olefin isomerization. The results also show that mercaptan could not be produced after the thiophene desulfurization because of the less content of H2S in the reaction system during S Zorb reaction adsorption desulfurization.
    Experimental study on removal of sodium formate from trimethylolethane by electrodialysis
    ZHANG Minqing1,LI Yan2,LI Jingyun2,MIAO Lei2
    2014, 33(11):  2848-2852. 
    Abstract ( 166 )  
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    The content of sodium formate in trimethylolethane is one of the important indicators for product performance. Electrodialysis instead of ion exchange resin was used to remove sodium formate from trimethylolethane. The influence of operating conditions, such as operating voltage, initial concentration in dilute chamber, flow rate of dilute chamber, initial concentration in concentrated chamber on desalination effects were investigated. Desalination ratio could reached 95% at operating voltage 8V, dilute chamber initial concentration 0.15mol/L, dilute chamber flow rate 0.529cm/s, initial sodium formate concentration in concentrated chamber 0.01mol/L. Electrodialysis could be used to remove sodium formate from trimethylolethane effectively. For environmental and resource consumption concerns, electrodialysis is better than ion exchange resin for removing sodium formate from trimethylolethane.
    Development of flame arrester performance testing system
    SUN Shaochen1,2,LIU Gang2,BI Mingshu1,ZHANG Zhiyi2
    2014, 33(11):  2853-2860. 
    Abstract ( 167 )  
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    Flame arrester is a kind of safety equipment which can prevent flammable gas and liquid vapors from spreading,and widely used in petrochemical and natural gas industry in recently years. In order to improve the flame arrester performance testing and detection level,this research focused on flame arrester performance testing system. The system designed was able to complete the test configuration of explosive mixture gas,explosion process pressure,flame velocity and temperature testing work,the analysis of the data processing work. The testing system included gas mixing apparatus,sensor detection system,data acquisition device. Gas mixing apparatus can realize the request of static-dynamic mixing with gas. Sensor detection system can achieve the function of fire recognition,temperature detection and the pressure detection. Data acquisition device can realize processing data,displaying experiment data in real-time,recording and processing the test data. The testing system considered sufficiently the security issues of the testing scene,and the testing precision can completely satisfy the testing requirements of flame arrester. This system was stable,reliable and quite simple in operation and met the national standards.
    Study on intensification of low interfacial tension system in reciprocating plate extraction column
    ZHANG Huijuan1,WANG Henan1,ZHANG Lühong1,HAO Li1,2,JIANG Bin1,2
    2014, 33(11):  2861-2867. 
    Abstract ( 174 )  
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    This paper studied the extraction performance of low interfacial tension system n-butanol-succinic acid-water (BSW) in a Reciprocating Plate Extraction Column (RPEC). Water as the solvent, extracted succinic acid from n-butanol phase. The experiment investigated the effects of flow rate,phase ratio, mass transfer direction and reciprocating rate upon the hydrodynamic and mass transfer performance. The results of extraction using stable sieve plate were compared. The results indicated that the reciprocating rate of plates should not be higher than 3.5cm/s to avoid emulsion. When phase ratio was 2.8,the operation approached the flooding point,and the experiment was not stable. The distribution of drops was better and the volumetric mass transfer coefficient was greater under the condition of higher flow rates and larger phase ratio. However, the range of increase was limited by the maximum throughput and the residence time of two phases. Due to its larger interface area, mass transfer direction from dispersed phase to continuous phase was beneficial in improving efficiency. The axial mixing in continuous phase was much more serious than in dispersed phase under the same operation conditions. Compared to stable sieve plate,the reciprocating plates can improve drops distribution increase the processing capacity and intensify mass transfer.
    Experimental investigation of heat transfer characteristics of condensation section in composite hollow heat pipe
    CUI Tengfei1,XIAO Zhangping1,CAO Malin2,ZHANG Lin1,JIANG Feng1
    2014, 33(11):  2868-2872. 
    Abstract ( 183 )  
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    The composite hollow heat pipe can effectively solve the problem of acid dew corrosion of heat exchanger equipment comprising ordinary gravity heat pipe,and has an important application in recycling waste heat of low temperature flue gas. A heat transfer experimental platform of composite hollow heat pipe was established,and the heat transfer characteristics of condensation section were investigated experimentally. A stainless steel tube of total length of 1080mm with methanol was studied. Electrical heating was used in the evaporation section and water cooling was used in the condensation section. Wall temperatures and inlet and outlet temperatures of cooling water were measured with K type thermocouples. Vapor saturation pressure in heat pipe was measured by vacuum pressure sensor. The effect of two parameters:filling rate (15%≤V+≤40%) and evaporator heat flux (9.48kW/m2≤q≤37.91kW/m2) on the heat transfer characteristics of condensation section were investigated. When filling rate was 20%,the composite hollow heat pipe had the maximum condensation heat transfer coefficient and showed the best isothermal characteristics of its condensation section and the best heat transfer performance. Besides,with the increase of evaporator heat flux,the effective condensation length of the composite hollow heat pipe and the condensation heat transfer coefficient increased. Experimental investigation provides a basis for industrial applications.
    Experimental study on heat transfer enhancement of assembled rotors of large and small diameters of same ratio
    HE Lichen,GUAN Changfeng,HE Changjiang,Zhang Chongwen,HE Jianyun,YAN Hua
    2014, 33(11):  2873-2877. 
    Abstract ( 176 )  
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    This paper researched on heat transfer enhancement and friction characteristics of tubes with alternatively arranged rotors with diameters 22mm and 19mm. Glycerin solution was used as tube-side working fluid and water was used as shell-side fluid. Experiment of smooth tube was carried out prior to the actual experiments,in order to ensure the reliability and accuracy of the experiment apparatus and methods. The experimental results revealed that:When rotors of diameters 22mm and 19mm were arranged at the ratio 1︰1,Nu and PEC were higher than when the ratio were at 2︰2 and 3︰3. The Nu value was 19.17%—34% higher than when the diameter was fixed at 19mm,and the PEC value was 1.78—2.37,indicating that the more frequent the two rotors were alternatively arranged,the better the effect of heat transfer enhancement was. The difference of resistance coefficients among the three scenarios was not significant compared to the situation when the diameter was 22mm,alternate arrangement of the large and small diameter rotors could be practical,considering saving materials and cost of industrial applications
    Study on heat-transfer performance of horizontal tube falling film evaporator
    XIE Lixin1,2,3,ZHOU Wenmeng1,2,3,CHEN Fei1,2,3
    2014, 33(11):  2878-2881. 
    Abstract ( 202 )  
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    Based on the horizontal tube falling film evaporation platform with heat-transfer area of 2.375m2,this paper studied the heat-transfer performance of the evaporator in low temperature multi-effect distillation (LT-MED),with 5052 aluminum alloy tubes as heat-transfer tubes and actual seawater as raw material. The effects of sprinkling density,evaporation boiling point,evaporation temperature difference,salinity and non-condensable gas concentration on the total heat-transfer coefficients of desalination process were investigated. The results showed that the following:within the testing scope,the total heat-transfer coefficient increased with the increase of sprinkling density and evaporation boiling point;the total heat-transfer coefficient decreased with the increase of evaporation temperature difference;the total heat-transfer coefficient decreased sharply when there was non-condensable gas mixed in the steam inside the heat-transfer tube;salinity had little effectd on the heat-transfer coefficient;the heat-transfer coefficients were more than 3500 W/(m2?℃) when controlling the concentration of non-condensable gas,These results provided an experimental basis for the engineering design and production optimization of desalination.
    Nucleation mechanisms in the emulsion polymerization of styrene at different surfactant concentrations
    XU Bingwen1,WANG Hong2,HE Yanping1,XIAO Xiaoqin1,SUN Yanlin1
    2014, 33(11):  2882-2887. 
    Abstract ( 279 )  
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    Formulation of latex with styrene (St),potassium persulfate (KPS) and sodium dodecyl sulfate (SDS) was investigated as a function of SDS surfactant concentration [S] to explore its nucleation mechanism. The results showed that micellar nucleation dominated the nucleation process when the concentration of SDS was ≥ 8 mmol/L; while,precipitation nucleation dominated the process at 2mmol/L. From 2mmol/L to 8mmol/L,both micellar nucleation and precipitation worked; and the contribution of micellar nucleation increased with the increase of the concentration of SDS. Additionally,the particle number of latex was calculated:Np∝[S]0.9 when [S] was ≥8mmol/L; Np∝[S]0.8 when 8mmol/L≥[S]≥2mmol/L.
    Process intensification of levulinic acid from glucose using sulfuric acid as catalyst
    JIANG Nan1,XIE Nan1,QI Wei1,2,3,SU Rongxin1,2,3,HE Zhimin1,2,3
    2014, 33(11):  2888-2893. 
    Abstract ( 294 )  
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    Levulinic acid (LA) was prepared from glucose at high temperature and with dilute sulfuric acid. The effects of reaction temperature,sulfuric acid concentration and stirring speed on glucose conversion and LA yield were investigated and optimized. Furthermore,the influence of initial glucose concentration on LA yield under the optimized reaction conditions was analyzed. For the purpose of increasing LA yield under high glucose concentration,two kinds of fed-batch experiments were performed (7%,6% and 5% glucose concentration for three additions;every 3% glucose concentration for six additions). High sulfuric acid concentration,high reaction temperature and high stirring speed were favorable to increasing glucose conversion and levulinic acid generation. High glucose concentration was not conducive to generation of levulinic acid,and the higher the concentration of glucose,the lower the yield of levulinic acid. Yield of levulinic acid increased from 44.3% to 65.9% via fed-batch experiment.
    Separation of n-hydrocarbons from high temperature oil phase products of Fischer-Tropsch synthesis
    WANG Yan1,GE Xihui2,ZHANG Minqing1,ZHU Huaigong3,ZHANG Zijian2,WANG Ming1
    2014, 33(11):  2894-2898. 
    Abstract ( 233 )  
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    The simulated high temperature oil phase products of Fischer-Tropsch synthesis were taken as raw materials and the urea inclusion method was used to separate n-hydrocarbons from the raw materials. The effects of activators,inclusion reaction conditions and unpacked reaction conditions on n-hydrocarbons separation were studied. Orthogonal experimental study showed that ethanol was a suitable activator and the optimal reaction conditions for inclusion were:reaction temperature 5 ℃,reaction time 1h,based on 1g raw materials,amount of urea 2.75g,amount of ethano 3.5mL,amount of water 1.125mL. Under the optimal reaction conditions,recovery rate of 1-decene was 87.75% and that of n-decane was 89.90%. The unpacked reaction results of inclusion complex illustrated that presence of water was conducive to the unpacked reaction and recovery rate of n-hydrocarbons was higher than without water. When water consumption reached 100 mL,the unpacked reaction of inclusion complex was completed.
    Process analysis and kinetics during co-pyrolysis of low rank coal and enteromorpha
    WANG Chunxia,HE Xuanming,AO Fulu,FENG Dongzheng,ZENG Xiancan,ZHANG Du
    2014, 33(11):  2899-2904. 
    Abstract ( 197 )  
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    The pyrolysis experiments of low rank coal (LRC),enteromorpha (EN) and their blends were performed in a special prolysis equipment. The maximum tar yield of blends was 11.39% with a EN ratio of 30%,which was increased by 28.61% compared to LRC pyrolysis alone and by 8.87% compared to calculated value. Thermogravimetric analysis (TGA) of LRC,EN and their blends indicated significant synergistic effect in the co-pyrolysis process of LRC and EN at 240—750℃. The relative maximum value of synergistic effect was 18.5%. Kinetics analysis showed compensation effect between activation energy and pre-exponential factor of co-pyrolysis. Blending of LRC and EN enhanced reactivity and lowered reaction rate. Synergistic effect mainly was reflected in enhancing the reactivity of co-pyrolysis.
    Effect of process parameters on determination of asphaltene from coal tar
    TIAN Panpan1,XI Xiaoming2,LI Dong1,SUN Zhihui1,LI Wenhong1
    2014, 33(11):  2905-2908. 
    Abstract ( 181 )  
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    Solvent analysis is a method for quantitative separation of coal tar into toluene insoluble,asphaltene (toluene soluble,pentane insoluble),and oil (pentane soluble). The prime objective was to identify the variables in the procedure,including aromatic solvent type,extraction method,amount of toluene solution concentrate (degree of toluene boil-off) ,alkane solvent type,and ratio of n-heptane to toluene solution concentrate that affected the precipitate obtained for asphaltene content. Substitution of toluene with benzene and extraction method did not have a large effect on the precipitate reported for asphaltene. Heptane was chosen as alkane solvent instead of pentane. However amount of toluene solution concentrate and ratio of n-heptane to toluene solution concentrate did have a large effect on the precipitate reported as asphaltene. Coal tar from northern Shaanxi province was tested. With the suitable time of ultrasonic extraction for 3 hours,toluene solution concentrate of 9mL,a 20-fold of n-heptane over toluene solution concentrate,the asphaltene precipitate determined was 13.4%. The separation conditions of asphaltene determination should be indicated when studying the properties and structure of asphaltene from coal tar,since the coal tar separation technique have a large effect on asphaltene precipitated.
    Research progress of feedstocks and deep-processing technologies for biodiesel
    ZHANG Zhiliang,JI Jianbing
    2014, 33(11):  2909-2915. 
    Abstract ( 223 )  
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    Biodiesel is a renewable biofuel consisting of fatty acid methyl esters (FAME). Research on biodiesel is developing rapidly in China. However,due to the high price of feedstocks and the lack of down-stream products,the biodiesel industry is uncompetitive. Much effort has been devoted to exploiting lower-cost feedstocks and developing diverse down-stream products. This paper reviews the current research progress of feedstocks and deep-processing technologies for biodiesel. The status,distribution and features feedstocks for biodiesel are summarized. The characteristics of biodiesel from different feedstocks are presented. Biodiesel development strategies in China are proposed. Progress in FAME deep-processing technologies are also reviewed. As an important raw material,FAME can be deep-processed for producing a variety of valuable chemical products,such as second generation biodiesel,biodegradable lubricati base oil,fatty alcohol,alkanolamide,fatty acid methyl ester sulfonate and green plasticizers. The main challenge for FAME deep-processing is to develop highly efficient catalysts.
    Development and trend of liquefaction technology and construction of large-scale natural gas liquefaction plant
    LIN Chang,BAI Gailing,WANG Hong,LI Yulong
    2014, 33(11):  2916-2922. 
    Abstract ( 296 )  
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    In the world,natural gas liquefaction technology has developed for nearly a century,and has been applied in industry for more than half a century,which leads to many matured liquefaction processes. While in China,the technology is developing only in recent ten years. The kinds of natural gas liquefaction process and its industrial application situation are presented,and the process characteristics and facility size and application scope are analyzed to provide guidance for research and development of domestic natural gas liquefaction technology. Mixed refrigerant process (DMR and C3MR) and optimized cascade process are the main options in large-scale liquefied natural gas (LNG) facility construction,and DMR is a new type process with high efficiency and flexiblity. Throughout the world,the facilities are distributed in a wide geographical scope,the facility scale expands unceasingly,the facilities in planning and those completed in the past twenty years are mostly 3.0~6.5Mt/a per train and are constructed onshore. Moreover,along with the development of the resources exploitation technology,polar and deep ocean resources exploitation and utilization are growing sharply,which makes liquefaction technology adapted to extremely cold climate conditions and floating liquefaction become new research hot spots.
    Review on application of heat pipe technology in lithium-ion power battery thermal management system
    HONG Sihui,ZHANG Xinqiang,WANG Shuangfeng,ZHANG Zhengguo
    2014, 33(11):  2923-2927. 
    Abstract ( 343 )  
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    With environment degradation and energy source depletion,high energy density lithium-ion power battery has attracted more and more attention. However,its wide use is still limited by characteristics,longevity and safety of lithium-ion. Lithium-ion can only work safely and effectively in a reasonable temperature period between 25℃ to 40 ℃,that requires a feasible thermal management system. This paper reviews the research progress of several cooling technologies used for lithium-ion battery,including air-cooling,liquid-cooling,phase change material cooling and heat pipe cooling. The applied lithium-ion thermal management system nowadays is complicated in structure,huge in size,heavy in weight and requires extra energy consumption. Hence,ultra-thin heat pipe is proposed as one of the solutions,and coupling of ultra-thin heat pipe with phase change material will meet the demand of heat dissipation and storage for lithium-ion power battery thermal management system.
    Discussion on development direction of polysilicon production technology
    WANG Dongjing,ZHAO Jian,ZHAN Shuihua,SHENG Bin
    2014, 33(11):  2928-2935. 
    Abstract ( 203 )  
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    High-frequency power conversion,silane fluidized bed process and vapor-to-liquid deposition can be combined with modified Siemens process to reduce production cost and improve quality of polysilicon. This paper summarizes modified Siemens process,silane fluidized bed process and vapor-to-liquid deposition,and analyzes their advantages and disadvantages as well as their development directions. The present modified Siemens process needs improvement of its core equipment and the application of high-frequency power conversion,the silane fluidized bed process needs to further research and develop the existing fluidized bed heating mode,the vapor-to-liquid deposition process can be combined with existing technologies to form a variety of process routes,and the combination of the silica carbochlorination process to prepare silicon tetrachloride and hydrogen reduction of silicon tetrachloride for preparing polysilicon can greatly shorten process route,make purification of silicon tetrachloride easier,and polysilicon can be produced with higher quality and lower cost.
    Supercritical CO2 fluid leaching of uranium from sandstone type ores using FeCl3 as reactant
    WANG Yanlong,TAN Kaixuan,QU Huiqiong,LI Chunguang,HU Yang,LI Yongmei
    2014, 33(11):  2936-2940. 
    Abstract ( 243 )  
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    Uranium is an important nuclear fuel,and supercritical CO2 fluid leaching is a new,efficient and environmentally safe uranium extraction method. The aim of this experiment was to investigate the impact of pressure and time on uranium leaching efficiency with FeCl3 as reactant. Leaching efficiency first increased and then decreased with the increase of pressure. Under a constant specific pressure leaching efficiency first increased with increasiing time and then stabilized at a fixed value. The optimum leaching pressure was 10MPa,and leaching efficiency could reach 90%. Compared with the traditional acid-alkali leaching of uranium,leaching effect was significantly higher. Supercritical CO2 fluid leaching could be used for in-situ uranium leaching of low grade sandstone-type uranium deposits.
    Development of titanium catalyst for cis-1,4-polyisoprene rubber
    WANG Zhaowei1,YU Junwei2,LIU Xiaoxuan1
    2014, 33(11):  2941-2946. 
    Abstract ( 287 )  
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    The performance of isoprene rubber synthesized by the titanium catalyst is comparable to that of natural rubber. The paper is aimed to introduce the domestic and abroad developments of cis-1,4-polyisoprene rubber,and to summarize the influence factors of kinetic behavior for the polyisoprene polymerization and the content of cis-1,4-polyisoprene configuration in the microstructure of rubber synthesized by titanium catalyst. An overview on the synthesis methods of cis-1,4-polyisoprene by titanium catalyst is conducted,and the developing trend for titanium cis-1,4-polyisoprene rubber is prospected. It can be concluded that developing a cheap titanium catalysis system is an inevitable trend in the synthesis of isoprene rubber,developing titanium high cis-1,4-polyisoprene should be the prime choice for polyisoprene synthesis industry. Some existent problems and possible research subjects for the further improvement of synthesis cis-1,4-polyisoprene are suggested and discussed.
    Heterogeneous saccharification of cellulose by solid acid
    ZHANG Yingshi,WANG Yan,WAN Jinquan,MA Yongwen,LIAN Jie
    2014, 33(11):  2947-2955. 
    Abstract ( 159 )  
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    As the main hydrolysate of cellulose,glucose is able to form a variety of important energy materials and valuable platform chemicals,such as fructose,sorbitol,furfural,and levulinic acid,through isomerization,dehydration,rehydration,hydrogenation,hydrogenolysis or other further reactions. Therefore,it is of great significance for the production of high additional value products by transforming cellulose into glucose,a crucial intermediate,with both high efficiency and excellent selectivity. This article is aimed to review ongoing research progress and to preview the future trends of five predominant types of heterogeneous catalysts,including sulfonated solid acid,H-type zeolite,metal oxide,supported metal and heteropolyacid,in the hydrolytic reaction of cellulose from the perspective of the interaction between the physical and chemical structures of the catalysts and their catalytic activity. The catalysts mentioned above have evident advantages in the ease of separation from products,recyclability,reusability,stability of catalytic activity and environmental influence,but still need improvement in cellulose contact and active components retainment. In the future,it shall be focused on enabling heterogeneous catalysts to absorb,dissolving and hydrolyzing cellulose through functional groups and stabilizing their active components through inner interactions of functional groups or immobilization.
    Progress in the catalytic decomposition of hydrous hydrazine for hydrogen production at mild conditions
    HE Lei,HUANG Yanqiang,WANG Aiqin,WANG Xiaodong,ZHANG Tao
    2014, 33(11):  2956-2962. 
    Abstract ( 293 )  
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    Hydrous hydrazine,N2H4?H2O,could be a promising hydrogen storage material due to its high hydrogen content (8.0wt%) and safe handling at mild conditions,with N2 as the only by-product. In this paper,the development of catalytic systems in hydrous hydrazine decomposition for H2 production was reviewed,including metallic nanoparticles,complex oxides,and supported catalysts. The mechanism of hydrazine decomposition was briefly introduced. The influencing factors for promoting H2 selectivity were discussed,including metal property,reaction conditions,and promoters. Also,the advantages and disadvantages of the reported catalysts were summarized,and performance development in hydrous hydrazine decomposition and other related reactions was also included.
    Effect of promoter MgO,CaO on the performance of CuO-ZnO-Al2O3 catalyst for methanol synthesis through CO2 hydrogenation
    GAO Wengui1,2,3,WANG Hua1,2,3,HAN Chong2,3,LIU Wenyan2,3,WANG Yuhao2,3,JIA Miaoyao2,3
    2014, 33(11):  2963-2969. 
    Abstract ( 325 )  
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    CuO-ZnO-Al2O3 was modified by co-precipitation,using MgO,CaO as promoters. The effects of MgO,CaO on phase composition and catalyst structure were illuminated by using N2 adsorption-desorption,TG-DTG,XRD,H2-TPR and CO2-TPD techniques. The catalysts were tested in the synthesis of methanol from CO2 hydrogenation in a fixed-bed reactor. It indicated that the addition of CaO favored the formation of aurichalcite (Zn,Cu)5(CO3)2(OH)6 and malachite zinc (Cu,Zn)2CO3(OH)2 in the precursor of the catalyst. The more (Zn,Cu)5(CO3)2(OH)6 or (Cu,Zn)2CO3(OH)2 precursor possessed,more synergy,lower reduction temperature after calcination it exhibited,which improved the catalytic performance of catalyst modified by CaO. The promoter of MgO did not benefit the formation of aurichalcite (Zn,Cu)5(CO3)2(OH)6 and malachite zinc (Cu,Zn)2CO3(OH)2,which led to less active catalyst due to the weak synergetic effect between Cu and ZnO. On the other hand,the formation of MgO-CuO solid solutions reduced the activity of the catalyst,although the crystallite size of CuO,ZnO was decreased and the dispersion of Cu on the surface was enhanced. It was also found that the intensity and amount of basic sites on the catalyst surface were modulated by the promoter of MgO,CaO. The CaO-modified CuO-ZnO-Al2O3 catalyst possessed stronger basic sites than that of MgO-modified,which was accordance with the basic strength order of CaO and MgO.
    Study on preparation and catalytic oxidation desulfurization performance of Ti-MCM-41 synthesized at different hydrolysis conditions
    WANG Guangjian,ZHANG Jinlong,CHU Yanpei
    2014, 33(11):  2970-2974. 
    Abstract ( 224 )  
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    Ti-MCM-41 mesoporous materials were synthesized through improved hydrothermal method with solution of cetyltrimethylammonium bromide (CTAB) and sodium hydroxide as template,tetraethylorthosilicate (TEOS) as silica source,tetraethylorthosilicate (TBOT) as titanium source. The influence of temperature of hydrolysis (30℃、60℃) and inhibitors of alcohols were investigated respectively. Products were characterized by XRD,SEM,TEM and other means. The results indicate that the molecular sieves obtained exhibit regular long-range ordered hexagonal mesoporous structure. The sample at hydrolysis temperature of 30℃ shows better crystallinity and long-range ordered structure. Desulfurization rate reached 96.7% under the condition:catalyst amount 0.1g/10mL(oil),reaction time 30min and desulfurization temperature 40℃. It can be summarized that lattice defects and poor long-range order are in favor of the removal of sulfur from diesel.
    Progress of biodegradable polylactic acid based composite material
    Lü Shanshan,TAN Haiyan,ZUO Yingfeng,GU Jiyou,ZHANG Yanhua
    2014, 33(11):  2975-2981. 
    Abstract ( 224 )  
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    Research and development of biodegradable materials is one of the effective approaches to solving the environmental pollution problems which come from the traditional petroleum-based plastics. Polylactic acid (PLA) has so many good properties such as full biodegradability,good thermal processibility,renewablility,high mechanical performance and so on. It is an inevitable trend to replace the petroleum-based plastics. However,the properties of hydrophobicity,poor toughness and high price are obstacles for the application of PLA. All of these result in attracting much attention in the research of modification of PLA. In this paper,the recent research on biodegradable PLA system including blending with natural polymer and synthetic polymer is summarized. The effect of processing technology,surface treatment and additives on the composite material is presented. Further research could be flexible polymer,surfactant,and various fibers to improve the brittleness,compatibility,and strength of the cromposite material.
    Advances in organic/inorganic hybrid alcohol perm-selective pervaporation membrane
    LI Jie,WANG Naixin,JI Shulan
    2014, 33(11):  2982-2990. 
    Abstract ( 194 )  
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    Alcohol perm-selective pervaporations membrane could resolve the product inhibition problem effectively for the use of ethanol and butanol recovery from fermentation process. The selection and modification of membrane material,and the construction of membrane structure are the key issues for better pervaporation performance. Organic/inorganic hybrid membranes combine the advantages of both organic polymers and inorganic materials,forming highly promising membranes for separation. This paper reviews the advances in organic/inorganic hybrid alcohol perm-selective pervaporation membrane materials. Several issues and research priorities which will impact the pervaporation ability of hybrid membrane for biofuel recovery are identified and discussed,including particle structure,particle size,compatibility and dispersion of inorganic particles in the polymer,and particle loading. Novel preparation methods in recent years are also presented in detail. Finally,the prospect of developing novel particles with nano size,superhydrophobic pores and polymer compatibility are presented,and the design ideas of constructing high loading,micro- and nanoscaled hierarchical structures with high affinity to alcohol are also illustrated.
    A preliminary analysis on the synthesis of layered Li-Ni-Co-Mn-O cathode material by co-precipitation method
    ZHANG Xiang1,WANG Chunlei1,KONG Jizhou1,ZHOU Fei1,TANG Zhou2,LI Junxiu2
    2014, 33(11):  2991-2999. 
    Abstract ( 199 )  
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    Due to its low cost and high capacity,layered Li-Ni-Co-Mn-O has already been industrialized and partially replaced traditional LiCoO2 as cathode material for commercial lithium-ion battery. Among various synthetic methods for Li-Ni-Co-Mn-O,co-precipitation becomes an attractive choice because of its low cost and stability. In this paper,we qualitatively analyzed the particulate and thermodynamic processes of co-precipitation method. Then influences of process parameters (aging time,temperature,pH value,etc) on the structure and performance of product were discussed in detail. The ranges of certain process parameters were confirmed according to statistics and the analyses conducted before. The concept of effective feeding rate was put forward,with which a series of variables were derived for a complete description of feeding process. Further researches on the synthesis of primary particles with preferred orientation and the investigation of appropriate fluid environment for co-precipitation should be conducted in the future.
    Functionalized carbon nanotube/polymer composite membranes for separation
    DENG Huining1,YANG Xiuli2,TIAN Ming2
    2014, 33(11):  3000-3006. 
    Abstract ( 145 )  
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    Carbon nanotube (CNT) shows exceptional properties,such as high mechanical strength,large specific surface,and excellent transmission characteristics,which made it a good candidate for composite membrane preparation. After chemical modification,CNTs were functionalized and easily dispersed in membrane. With a brief introduction of the modification of carbon nanotubes and methods for preparing CNT-based composite membranes,the effects of the functionalized CNTs on hydrophilic,water flux,separation performance and the mechanical stability of membranes are reviewed in detail in this article. The recent development of CNT orientation in polymer membrane and its effect on the properties of membrane were also summarized. Due to the anisotropy of CNTs,using electric field,magnetic field and flow field to orientate the CNTs in membrane to make full use of its superior performance shall be the future focus of research on composite membrane.
    Progress in designing CO2 photocatalyst based on energy band match theory
    PENG Hui1,WU Zhihong2,ZHANG Jianlin2,LU Jing1,WU Chenxiao1,LI Peiqiang1,YIN Hongzong1
    2014, 33(11):  3007-3012. 
    Abstract ( 240 )  
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    In the process of photocatalytic reduction of CO2,visible light could be absorbed perfectly by the catalyst with a narrowed band gap,but those absorbed light could not be entirely devoted to photocatalytic reduction of CO2,as photocatalytic reduction performance is directly related to energy band location and band structure changing has an important influence on redox ability. Beginning with the CO2 photocatalytic reduction basic principles,this paper is aimed to introduce the basic reduction process of CO2 by semiconductor photocatalyst,the decisive role of valence band and conduction band;to briefly discuss the existing mismatch problem of valence band and conduction band in the process of photocatalytic reduction of CO2;and also to describe how to improve the CO2 photocatalytic reduction efficiency using energy band match theory,such as crystal growth,composite materials,form “p-n junction” and the First Principles,which provides theoretical references for the selection and design of catalyst for the photocatalytic reduction of CO2.
    Recent advances in functional monomers in ion-imprinted polymer
    ZHU Caiyan1,2,MA Huimin1,ZHANG Qiang1,ZHANG Tianlin2
    2014, 33(11):  3013-3020. 
    Abstract ( 180 )  
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    This paper is aimed to describe the research progress in several functional monomers in terms of their performance,advantages,and applications. The elaborated functional monomer contains the categories of organic acids (methacrylic acid,acrylic acid and vinyl benzoic acid),aromatic heterocyclic (pyridine,imidazole,amides and quinolines),the Schiff base and Salen ligand. Furthermore,the adsorption characteristics and application performances of ion-imprinted polymer produced with the above-described monomers are illustrated. Combined with our recent works in salicylaldehyde Schiff bases functional monomer containing quaternary ammonium ion,the development trend of functional monomer is also prospected. Not only species of functional monomers requires further enriched,but also their function and performance have to be improved. Among those,the functional monomer of 5-chloro methyl salicylic aldehyde Schiff’s base modified with quaternary ammonium salt possesses shows strong hydrophilic properties and multi-functional characteristics,and a future research focus shall be the investigation on its performances in the application of functional monomers.
    Analysis on technological conditions and optimization approach of Schlesinger process for sodium borohydride production
    HOU Dianbao1,LI Haimin1,DANG Ya1,2
    2014, 33(11):  3021-3025. 
    Abstract ( 235 )  
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    Currently,Schlesinger process and Bayer process are both industrial synthesis process of sodium borohydride. The Brown-Schlesinger process is the major process in use today for making sodium borohydride. The key steps of the process are the production of sodium hydride and trimethyl borate. The synthesis process of sodium hydride,trimethyl borate and sodium borohydride are reviewed. The existing problems are commented,such as sodium hydride prepared in mineral oil is poor in activity,serious environmental pollution caused by excessive use of concentrated sulfuric acid in industrial production of trimethyl borate. Some directions for further study are given. Integration of the process steps from start to finish will impact the bottom line cost. Synthesis of trimethyl borate instead of using sulfuric acid and purification by the salting out method can both reduce environmental pollution. In the process of sodium borohydride hydrolysis use of liquid dilute alkali solution instead of fresh water can avoid sodium borohydride hydrolysis and improve product yield.
    Preparation of copper ferrite composite oxide by combustion and its photocatalytic study
    LI Xiuping,YAN Song,ZHAO Rongxiang,LI Dandong
    2014, 33(11):  3026-3030. 
    Abstract ( 206 )  
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    In this paper,composite oxides of copper ferrite were prepared by combustion with ascorbic acid as a new combustion agent. The effect of the molar ratio of ferric nitrate and copper nitrate on composites was investigated by XRD. The composite was characterized by scanning electron microscopy,BET and UV spectra. The photo-catalytic properties of composites were studied with rhodamine B as degradation aim. Effect of catalyst amount,solution pH,hydrogen peroxide amount,the composite type on photo-catalyst were studied. The results indicated that the best photo-catalytic effect was achieved under UV light when the dose of catalyst is 0.4g/L,pH is 9,the amount of hydrogen peroxide is 5mL/L,the CuFe2O4 composite with the molar ratio of ferric nitrate,copper nitrate and ascorbic acid is 2∶3∶1,and the composite is also a better decolorizing agent.
    Improving CO2 separation performance of PEGDME-PVDF/PP composite membrane
    XIAO Junli,HE Gaohong,DAI Yan,LI Hao,ZENG Qingrui,HUANG Zhan
    2014, 33(11):  3031-3036. 
    Abstract ( 192 )  
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    Membrane technology is widely used in the field of CO2 separation due to its characteristics of low investment and simple equipment. The core of membrane technology is the material. According to research,the existence of ethylene oxide (EO) in polymer can effectively improve CO2 permeability and selectivity. Polyethylene glycol dimethyl ether (PEGDME),a promising material for CO2 separation,is rich of EO units,and its methyl end groups provide higher CO2 diffusivity. The polyethylene glycol dimethyl ether (PEGDME) was proposed to blend with PVDF as a selective layer for CO2 in this study,and the PEGDME-PVDF blend selective layer was fabricated on a porous support layer of polypropylene (PP) by solvent evaporation method to manufacture PEGDME-PVDF/ PP composite membranes for CO2 separation. With the increase of PEGDME content in the blend membrane,both CO2 permeability and CO2/N2 selectivity tend to rise. When the content of PEGDME reached 50wt%,CO2 permeability was 42.9GPU and CO2/N2 selectivity was 47.5. With the increase of PVDF concentration,CO2 permeability tended to decrease while CO2/N2 selectivity increased slowly. With the decrease of solvent evaporation temperature,PVDF crystallization decreased accordingly,and better membrane performance can be obtained. At solvent temperature of 30℃,the PEGDME- PVDF blend membrane performed excellently with CO2 permeation rate up to 84.7GPU,and the CO2/N2 selectivity was as high as 47.2.
    A novel isoleucine dioxygenase and its expression in recombinant Escherichia coli for synthesis of 4-hydroxyisoleucine
    FU Minjie1,NIE Yao1,MU Xiaoqing1,XU Yan 1,2,XIAO Rong3
    2014, 33(11):  3037-3044. 
    Abstract ( 227 )  
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    Isoleucine dioxygenase (IDO) could hydroxylyze L-isoleucine (L-Ile) to produce 4-hydroxy-L-isoleucine (4-HIL),which increases glucose-induced insulin release and is usually used in pharmaceuticals with antidiabetic and cholesterol-reducing properties. The strain with dioxygenase activity was screened from nature via combination of reaction coloration assayed by spectrophotometer and thin-layer chromatography (TLC). The gene encoding IDO (ido) was cloned and expressed in Escherichia coli and the constructed recombinant strain exhibited the function of isoleucine hydroxylation. The reaction conditions were optimized and the yield of transformation with the recombinant whole cells was increased to more than 85% by incubating the cells overnight at 30℃. The newly identified IDO and involved recombinant whole cells would be promising to prepare 4-HIL with high efficiency.
    Progress of synthesis of indanones
    CHAI Fenglan,XU Haiyun
    2014, 33(11):  3045-3052. 
    Abstract ( 236 )  
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    Indanones are found in a large number of natural products. Indanones possess a variety of physiological activity and are utilized as important intermediates in organic synthesis of medicines,pesticides and dyes. The cyclization method for the synthesis of indanone is discussed,and intramolecular Friedel-Crafts cyclization is the classical process of indanone synthesis. The advantages of this method are mature technology,simple post-processing and easy industrialization; its disadvantages are a large number of scrap liquid including aluminium,which pollute the environment. Meanwhile,the recent methods (e.g. rearrangement and photochemical method) for the synthesis of indanones are reviewed. Compared with the classical synthesis methods,the recent methods have advantages of mild conditions,fewer steps,and high purity of indanones. But the new methods are not easy to achieve industrialization due to limitation of raw materials and other conditions. The focus of indanone synthesis in the future is to develop green processes of atom economy and easy industrialization.
    Preparation of 1,4-dihydroxyanthraquinone from hydrolysis of 1,4-dichloroanthraquinone
    WANG Guicheng,DUAN Zhengkang,YAN Zhixiang
    2014, 33(11):  3053-3056. 
    Abstract ( 186 )  
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    1,4-dihydroxyanthraquinone was obtained by boric acid catalytic hydrolysis of 1,4-dichloroanthraquinone,which was synthesized by using commercial phthalic anhydride and p-dichlorobenzene as raw materials. The effect of reaction temperature,sulfuric acid concentration (mass concentration),molar ratio of reactants and reaction time on the chlorine hydroxylation reaction was investigated,and optimal experimental conditions were obtained as follows,temperature 220℃,sulfuric acid concentration 95%,molar ratio of sulfuric acid/1,4-dichloroanthraquinone/boric acid 37.5∶1.0∶1.4,reaction time 60min. Under above conditions,the yield of 1,4-dihydroxyanthraquinone was 71.0%. The possible mechanism of chlorine hydroxylation with the catalytic effect of boric acid was discussed.
    Preparation of di(2-ethylhexyl)1,2-cyclohexane dicarboxylate by hydrogenation
    FEI Yanan,ZHAO Jia,LI Xiaoguo,SUN Guofang,GAO Peng,ZHENG Xiuxin,LIU Youpeng,YU Haibin
    2014, 33(11):  3057-3060. 
    Abstract ( 242 )  
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    Di(2-ethylhexyl)1,2-cyclohexane dicarboxylate was prepared,by using bis(2-ethylhexyl) phthalate (DEHP,industrial grade) as raw material,and with fixed-bed hydrogenation process and noble metal Ru-Pd catalyst. The influence of temperature,pressure,space velocity and volumetric ratio of hydrogen to oil on catalytic activity were investigated. Under process conditions of reaction temperature 190℃,pressure 15MPa,space velocity 0.5h?1 and volumetric ratio of hydrogen to oil 800∶1,DEHP conversion was above 99.99% and selectivity was higher than 99.7%. Moreover,the catalyst kept excellent hydrogenation activity during 8000h test running.
    Continuous synthesis process of ε-caprolactone from oxidization of cyclohexanone in micro-channel reactor
    YAN Shenghu1,HAN Lingling1,SHEN Wei2,SHEN Jiefa1,LIU Jianwu1,ZHANG Yue1
    2014, 33(11):  3061-3066. 
    Abstract ( 218 )  
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    Peracetic acid was prepared as an oxidant from acetic anhydride and H2O2 firstly,and then ε-caprolactone was synthesized by Baeyer-Villiger oxidization of cyclohexanone in a continuous flow micro-channel reactor. The effects of reactants molar ratio,reaction temperature and residence time on reactant conversion and product yield were investigated for both preparation of peracetic acid and synthesis of ε-caprolactone,and the process conditions were optimized. Under conditions of n(acetic anhydride) ∶n(H2O2) = 1.2∶1,reaction temperature at 70℃,residence time of 115s,conversion of H2O2 reached 88.9% and yield of peracetic acid reached 86.7%. Under conditions of n(peracetic acid) ∶n(cyclohexanone) = 1.1∶1,reaction temperature at 90℃,residence time of 90s,conversion of cyclohexanone reached 96.2% and yield of ε-caprolactone reached 80.9%. Comparing with the traditional batch reaction process,the selectivities and yields of target products in this continuous micro-channel reaction process were increased with shortened reaction time and lessened raw material consumption,and process continuity ensured higher operation safety.
    Progress on treatment and comprehensive utilization of concentrated seawater
    LI Boyi,WANG Jianyou
    2014, 33(11):  3067-3074. 
    Abstract ( 228 )  
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    Re-desalting of concentrated seawater produced from seawater desalination process can further improve the recovery rate of freshwater and avoid wasting the high quality mineral resources and eliminate pollution to the marine environment. This paper reviewed the following techniques particularly:multi-effect distillation,eutectic freezing crystallization,electrodialysis,membrane distillation and membrane distillation-crystallization. The principle,applications,advantages and shortcomings of these techniques were analyzed. The development of comprehensive utilization and “zero liquid discharge” of concentrated seawater based on diverse hot-film integration process were discussed. Except for the relatively mature multi-effect distillation and electrodialysis,most of other techniques are still in the laboratory stage. This paper indicated that membrane distillation driven by renewable energy coupled with reverse osmosis developing efficient salt chemical industry would be one of the most promising methods of concentrated seawater desalination.
    Process enhancement of anaerobic Ammonium oxidation
    GUO Qiong,JIN Rencun
    2014, 33(11):  3075-3081. 
    Abstract ( 227 )  
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    Anaerobic ammonium oxidation(Anammox) is a novel and cost-effective technology with high nitrogen removal capacity. However,the sensitivity to environmental conditions, and the vulnerability to many pollutants limit the applications of Anammox process. The process enhancement could be an effective measurement to solve these problems. This paper investigated the enrichment of Anammox(including the acceleration of granulation,adding the carrier for formation of integrated biofilm-granule system,the equipment of membrane biological reactor,etc.),the addition of chemical substances(such as manganese dioxide,the graphene oxide,iron ion,the intermediate of Anammox etc.),the application of physical field (including ultrasonic,magnetic field,electric field and so on) as well as bio-augmentation and sequential biocatalyst addition. This paper also analyzed the main technical focuses,explained the mechanisms,and compared the potential of different methods along with the deficiency. It was pointed out that certain aspects,such as the parameters optimization,the combination of different enhancement methods,and the long-term effects as well as the in-depth study of the mechanism,still need to be further investigated.
    Progress of hydrophobic membrane and process for oil/water separation
    YANG Zhensheng1,LI Liang1,ZHANG Lei 2,WANG Zhiying1,LI Baichun1
    2014, 33(11):  3082-3089. 
    Abstract ( 229 )  
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    This paper summarized the types of hydrophobic porous membrane for oil/water separation,including conventional membranes and highly hydrophobic/superolephilic membranes. Conventional membranes are for microfiltration,ultrafiltration and nanofiltration process currently. With greater water contact angle (≥120°),the highly hydrophobic/superolephilic membrane have highly hydrophobic surface and cover modified meshes,modified fibers,modified filter paper,composite membranes and asymmetry membranes. It is possible that the fouling resistant membrane for oil/water separation lies on highly hydrophobic/superolephilic membranes. Principles and current applications of oil/water separation process with hydrophobic membrane were discussed. In disposition process of oily wastewater,the membranes take part in demulsification of O/W emulsion,coalescence of oil droplets,filtration of oil droplets and adsorption of oil molecules respectively. In purification process of watery oil,the membranes act as selective media,where continuous oil phase is permeated and water droplets is rejected. The preparation of highly hydrophobic/superolephilic membranes,the systematic investigation to oil/water separation process and the large scale tests with industrial system,were also discussed.
    Research on extraction characteristics of cyanide wastewater by emulsion liquid membrane system
    DANG Longtao,XUE Juanqin,LI Guoping,LIU Nina
    2014, 33(11):  3090-3094. 
    Abstract ( 192 )  
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    The cyanide wastewater was treated by emulsion liquid membrane method using three octyl amine(TOA) as carrier,kerosene as membrane solvent,liquid paraffin as membrane additives,and NaOH solution as aqueous phase. Cyanide extraction rate was influenced by surfactant dosage,mobile carrier dosage,and concentration of NaOH in the liquid phase. The experimental results showed that the extract rate of cyanide can reach above 95% in the following condition:2% of TOA volume fraction,3% of surfactant Span-80 volume fraction,1% of liquid paraffin volume fraction,2% of mass concentration of NaOH in the internal phase is,1∶1 of volume ratio of oil to internal phase is,1∶7 of volume ratio of emulsion liquid to wastewater,and 15 min of extraction time. Under the optimum condition,the different initial concentrations of cyanide wastewater of 322.23 mg/L,483.35 mg/L,644.46 mg/L and 966.70 mg/L were studied in order to obtain the optimal range of the initial concentrations. The results showed that the extract rate of cyanide can reach above 95% when the rang of initial concentration of cyanide wastewater was 300—500 mg/L.
    Investigation on calcination and carbonation performance of papermaking lime mud
    HE Lanlan,YU Dunxi,ZENG Xianpeng,Lü Weizhi,WU Jianqun,XU Minghou
    2014, 33(11):  3095-3100. 
    Abstract ( 200 )  
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    Papermaking lime mud is an alkaline industrial waste,taking large land resources in landfill. The use of lime mud to capture CO2 from the industry flue gas is one of the effective ways to solve the problems. However,some fundamental problems still need to be investigated. This paper compared the calcination of lime mud and limestone,and investigated the carbonation of the calcined products in a TGA reactor. The results showed a higher decomposition rate for lime mud than for limestone,leading to a shorter time for complete calcination. After the same calcination process (850℃,N2,15min),CaO derived from lime mud showed a lower carbonation conversion ratio than limestone. This was likely because of the lower specific surface area of CaO derived from lime mud. The influence of temperature on the carbonation performance of the calcinates derived from lime mud and limestone was similar. Increasing temperature in the range of 600—700℃ did not have insignificant effects on the carbonation rate in the fast chemical reaction-controlled carbonation stage. However,it lengthened the fast carbonation stage and resulted in a higher ultimate carbonation conversion ratio.
    Quantitative analysis on CO2 absorption and desorption in monoethanolamine (MEA) solution by using 13C NMR
    GUO Chao,CHEN Shaoyun,CHEN Siming,ZHANG Yongchun
    2014, 33(11):  3101-3106. 
    Abstract ( 448 )  
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    13C NMR spectroscopy is a suitable analytical method to get quantitative information on the species distribution in aqueous amine solutions loaded with carbon dioxide (CO2). 13C NMR is used for quantitative analysis on CO2 absorption and desorption in monoethanolamine (MEA) solution. Temperatures of absorption and desorption experiments are 313K and 393K,respectively. From 13C NMR spectroscopy,it is found that the main MEA species under the absorption conditions studied are free amine,protonated amine,MEA carbamate,and HCO3?/CO32?. At absorption step,MEA carbamate is produced first,when CO2 loading is getting higher to 0.455mol CO2/mol amine in this experiment,HCO3?/CO32? appears. The mole fraction of the MEA carbamate increases first with absorption time,reaches their maximum,and then decreases. The mole fraction of HCO3?/CO32? consistently increases with the increase of absorption time. At the desorption step,the mole fraction of MEA carbamate increases at early stage,reaches a maximum,and then decreases up to the end. After the desorption process,all HCO3?/CO32? can be stripped while about 75% of MEA carbamate still exist in the MEA solution.
    Effects of atmosphere pretreatment on the catalytic activity of Pd/γ-Al2O3 catalyst in benzene degradation
    ZHANG Jinyong1,2,LIU Ji1,CHEN Yu1,YANG Mingde1,WU Yulong1
    2014, 33(11):  3107-3111. 
    Abstract ( 160 )  
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    The effects of various atmospheres (oxidative,reducing and inert atmosphere) pretreatment on the catalytic activity of Pd/γ-Al2O3 catalyst in benzene degradation were studied in this paper. The property of the catalyst was characterized by X-ray photoelectron spectroscopy (XPS),X-ray diffraction (XRD) and transmission electron microscopy (TEM) analysis,and a possible influence mechanism of reducing,oxidative,and inert atmosphere pretreatment on the catalytic activity of Pd/γ-Al2O3 catalyst was proposed. The experimental results revealed that the pretreatment with reducing and inert atmosphere has a significant positive effect on the catalytic activity in benzene oxidation at a certain temperature. Crystal structure of Pd active species is another important factor to affect the catalytic activity besides chemical state. The pretreatment of inert atmosphere led to the change of crystal structure,with crystalline PdO transformed to amorphous state,and this change in crystal structure is beneficial for enhancing the catalytic activity.
    Research of MVR system with twin-screw vapor compressor in lye recovery
    GAO Lei,ZHANG Kai,DONG Bing,XING Ziwen
    2014, 33(11):  3112-3117. 
    Abstract ( 244 )  
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    Lye recovery using heat pump is beneficial in pollution control and energy saving in the industry of printing and dyeing. This paper investigated mechanical vapor recompression (MVR) system with twin-screw vapor compressor instead of Roots or centrifugal compressor to solve the problem of insufficient number of effects caused by small temperature rise in the lye recovery heat pump system. The mathematical model of every component of the system was built,the feasibility of the system’s operation conditions were evaluated,and the thermal performances of different effects of MVR systems and thermal vapor recompression (TVR) systems were simulated and calculated under the suitable operation conditions,and the economic effects of the two systems were compared. The results showed that the TVR system was not favorable when the waste lye was concentrated from 4% to 30% at 1 atm. In addition,the theoretical COP of each MVR system was over 20, and the theoretical COP and the heat exchange area increased with the increase of number of effects. The economical efficiency of the heat pump system with twin-screw vapor compressor was better than other systems in the waste lye recovery process. Applying three-effect system with twin-screw vapor compressor to lye recovery can achieve better energy saving.
    Simulation analysis and improvement on fractionation column in delayed coking unit
    ZHANG Long1,ZHAO Yaxin2,FANG Xiangchen1,DU Weiqian3,GAO Jingshan1,BO Dechen1
    2014, 33(11):  3118-3124. 
    Abstract ( 188 )  
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    It was planned to increase the capacity of 2# DCU (delayed coking unit) in Sinopec a Petrochemical from 1.4Mt/a to originally designed 2.2Mt/a. The blocked holes on trays of fractionation column would be opened. Meanwhile,the properties of crude oil changed greatly in recent years,especially asphaltene content. For pre-estimating operating performance of fractionation column after capacity recovery,production data were collected. Its problems in operation were analyzed by building a process calculation model. Moreover,the influence of tower structure on separation accuracy was analyzed. Referring to capacity recovery of fractionation column,improvement suggestions were made and verified by simulation and hydraulic calculation to provide the basis for operation optimization and transformation of fractionation tower and the theoretical guidance for fractionation column stable production after capacity recovery.