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05 June 2014, Volume 65 Issue 6
    CIESC Journal(HUAGONG XUEBAO)Vol.65 No.6 May 2014
    2014, 65(6):  0-0. 
    Abstract ( 237 )   PDF (1665KB) ( 229 )  
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    Coated mesh film based on superhydrophilic and superoleophobic principle and its application in oil-water separation
    YUAN Teng, CHEN Zhuo, ZHOU Xianhong, TU Weiping, HU Jianqing, WANG Feng
    2014, 65(6):  1943-1951.  doi:10.3969/j.issn.0438-1157.2014.06.001
    Abstract ( 1397 )   PDF (10010KB) ( 1867 )  
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    This paper reviews the research progress of membranes based on the principle of superhydrophilicity and superoleophobicity and its application in the oil-water separation. First, the fundamentals of the research are introduced, including those for preparing superhydrophilic and superoleophobic membranes and separation process, basic properties of membranes and influencing factors. The applications of liquid bridge principle in the superhydrophilic and superoleophobic membranes, membranes structures, general raw materials and prepared methods are also introduced. Then a comprehensive overview is given on the research progress of current common types of membranes, mainly including the stimuli-responsive superhydrophilic and superoleophobic membranes, superhydrophilic and underwater superoleophobic membranes, inorganic crystalline nanowires superhydrophilic and superoleophobic membranes, molecular brush structure superhydrophilic and superoleophobic membranes, and membranes for effective separation of oil-in-water emulsions. Finally, some problems in the current research area are advanced, including the basic theory of membrane separation, raw materials of membrane, membrane flux, membrane life, range of application, etc., and the development trends are prospected.
    Structural characteristics and reactivity of green rust
    CHEN Ying, WU Deli, ZHANG Yalei, CHEN Jie
    2014, 65(6):  1952-1960.  doi:10.3969/j.issn.0438-1157.2014.06.002
    Abstract ( 2158 )   PDF (944KB) ( 1238 )  
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    Green rusts (GRs) are transition state compounds containing both ferrous and ferric iron, which have attracted much attention worldwide due to low cost for preparation, high adsorption and reduction efficiency, strong reactivity and large specific surface area, but few studies have been done in China. GRs can form the inner layer complex by absorbing heavy metal ions, organic anions and inorganic ions for the layered double hydroxides (LDH) interlayer structure. Ferrous iron of green rust has a lower reduction potential and high activity. It plays a key role in pollutant removal in alkaline hypoxic environment, thus GRs are of great importance in water pollution remediation. This review summarizes the latest representative achievements in the use of green rusts for wastewater treatment and reaction mechanisms, including preparation characterization, structural characteristics, adsorption and reduction mechanisms of green rusts. The challenges and future research trends of green rusts application with structural ferrous iron are suggested.
    Thermodynamic calculations for reactive sorption enhanced reforming of C2/C3 light hydrocarbons
    WU Rong, WU Sufang
    2014, 65(6):  1961-1970.  doi:10.3969/j.issn.0438-1157.2014.06.003
    Abstract ( 939 )   PDF (860KB) ( 356 )  
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    In order to extend the use of raw materials of reactive sorption enhanced reforming process (ReSER) for hydrogen production, a thermodynamic analysis on cock oven gas (COG) containing C2/C3 light hydrocarbons, such as C2H4, C2H6, C3H6, and C3H8, were carried out for the feasibility and optimization operation conditions by using simulation software Aspen Plus. The calculations are based on the system pressure of 0.1-5 MPa, reaction temperature of 200-800℃, steam to carbon molar ratio (S/C) of 1-8, and calcium oxide to carbon molar ratio (Ca/C) of 0-5. The calculation results show that the products with over 95% H2 can be obtained by ReSER process using COG as raw materials under the optimized reaction conditions of S/C of 4, Ca/C of 2.5, reaction temperature between 200℃ and 650℃, and system pressure between 0.1 and 1.8 MPa. The H2 content in products increases with the increase of S/C or Ca/C. For selected CO2 removal ratio over 0.9, the H2 molar fraction is over 95% when the reaction temperature of C2H4, C2H6, C3H6 and C3H8 is over 250℃, 400℃, 250℃ and 350℃ respectively, at S/C of 4 and Ca/C of 2.5. For CO2 removal ratio lower than 0.9, the reaction temperature of C2H4, C2H6, C3H6 and C3H8 should be 50℃ higher for H2 molar fraction more than 95%. Among hydrocarbons with the same C number, it is easier for alkenes to present ReSER process than alkanes. The raw material with more C number is more easily to have ReSER process.
    Entropy production characteristics through n-heptane evaporation in low Reynolds number incoming air flow
    GUO Yangyu, ZHANG Haochun, YU Haiyan, JIN Yan, LI Yao
    2014, 65(6):  1971-1977.  doi:10.3969/j.issn.0438-1157.2014.06.004
    Abstract ( 763 )   PDF (1104KB) ( 529 )  
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    The main component of vehicle internal combustion engine and aircraft engine fuel is n-heptane. Combustion of liquid fuel belongs to diffusive combustion. The combustion process is composed of atomization, evaporation and diffusive combustion, and the evaporation process is vitally important, which critically determines the combustion speed of fuel droplet. Hence it is essential to optimize this process. In this paper, the evaporation of n-heptane droplet was evaluated from the perspective of second law of thermodynamics. A two-dimensional quasi-steady state model of the evaporation process was proposed, and the entropy production of the process was solved by integration of the volumetric entropy production rate in the whole domain. The viscous, conductive, mass transfer entropy production was investigated and compared, with the help of viscous and conductive entropy production rate equations reported in literatures and mass transfer entropy production rate equation derived in this paper, after numerical simulation of the evaporation process with Fluent software. Also, the relative total entropy production was defined. Conductive entropy production was the main part of the total entropy production of n-heptane evaporation in the low-Re air flow. With increasing Re and temperature of airflow, relative total entropy production decreased. In other words, the evaporation process produced less entropy relatively and it became easier, which from a thermodynamics perspective was optimal.
    Application of PC-SAFT with updated binary interaction parameters in phase equilibrium calculation for supercritical ethylene coordination polymerization system
    CHEN Keran, TIAN Zhou, LUO Na, DU Wenli, QIAN Feng, LIU Boping
    2014, 65(6):  1978-1986.  doi:10.3969/j.issn.0438-1157.2014.06.005
    Abstract ( 1110 )   PDF (977KB) ( 522 )  
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    Supercritical olefin coordination polymerization technology is one of the most important progresses in polyolefin industry, and accurate calculation of the binary phase equilibrium of this supercritical system with polymer is the key for the design and operation of this process. In this study, the equation of state of perturbed-chain statistical associating fluid theory (PC-SAFT EOS) with updated parameters is applied to binary phase equilibrium in supercritical ethylene polymerization system. Based on the pure component parameters and phase equilibrium data in literatures, the binary interaction parameters between supercritical fluid-solvent, supercritical fluid-monomer, comonomer (1-butene), chain transfer agent (hydrogen), circulation cooling gas (nitrogen) and polymer (PE) are regressed, and calculation results are compared with experimental data in literatures. The results show that re-parameterized PC-SAFT can accurately predict the thermodynamic properties and phase equilibrium of supercritical ethylene coordination polymerization system in a wide range of temperature (340-380 K) and pressure (2.0-7.0 MPa). The PC-SAFT EOS is validated by industrial data. The calculated supercritical fluid mixed density, vapor mixed density, and molar ratio of hydrogen to ethylene agree very well with industrial data for two product grades in the industrial process, with an average error less than 3%. The results provide a solid basis for further simulation and optimization of this supercritical process.
    Determination and correlation of solubility of bismuth oxychloride in hydrochloric acid solution
    ZHANG Di, XIAO Qinggui, ZHANG Bingzhu, XU Yongquan, XU Hongbin, ZHANG Yi
    2014, 65(6):  1987-1992.  doi:10.3969/j.issn.0438-1157.2014.06.006
    Abstract ( 889 )   PDF (456KB) ( 454 )  
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    For bismuth oxychloride (BiOCl) precipitation from BiCl3-HCl-H2O system, it is important to obtain its solubility in hydrochloric acid solution and correlate the data between bismuth oxychloride solubility and some parameters, such as temperature and pH value. In this study, solubility of BiOCl in hydrochloric acid solution was experimentally determined by the equilibrium method in the temperature range from 303.15 to 363.15 K. The experimental data are correlated by Apelblat equation, Empirical equation and λh equation. The results show that BiOCl solubility increases with the increase of temperature and concentration of hydrochloric acid solution. The concentration of hydrochloric acid solution has greater effect than temperature on the solubility of BiOCl. The solubility data for BiCl3-HCl-H2O system are well correlated by Apelblat equation, Empirical equation and λh equation, with the fitting accuracies of 0.99, 0.98 and 0.93, respectively, among which Apelblat equation is the best.
    Caking property destruction and particle fluidization for caking coal in fluidized bed by jetting pre-oxidation
    ZHAO Feixiang, ZHAO Zhigang, ZHANG Juwei, ZENG Xi, CHU Mo, XU Guangwen
    2014, 65(6):  1993-2002.  doi:10.3969/j.issn.0438-1157.2014.06.007
    Abstract ( 1032 )   PDF (3197KB) ( 392 )  
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    The existing gasification technologies can hardly treat the coal like washing middlings that has caking index above 10 and also ash content, as high as above 40% (mass). Coal industry, such as coking industry, however, has great need to gasify this kind of coal for realizing its value-added utilization. Institute of Process Engineering (IPE), Chinese Academy of Sciences (CAS) proposed the jetting pre-oxidation fluidized bed gasification (JPFBG) to treat such a kind of coal. Coal particles are fed into the dilute zone of a fluidized bed reactor with a gas jet containing oxygen to implement the destruction of coal's caking property. The jetting feed also strengthens gas-solids contact and accelerates gasification reaction. This study was devoted to characterizing the destruction of coal caking property via jetting feed of coal in a bench-scale fluidized bed with jetting pre-oxidation for a kind of powder coal with caking index of about 20. The tested parameters included equivalence ratio (ER) and O2 concentration (CO2) in the jetting gas and reaction temperature (T). The results were analyzed in terms of time-series temperature in the reactor, time-series product gas composition and char characteristics given by SEM and FTIR analyses and gasification reactivity. The operational conditions for fully destroying the caking property of the tested coal were T>950℃,CO2=21% (vol) and ER>0.1. In this case the temperature in the feeding zone of the reactor was steady and the H2 and CO concentrations in the product gas were very low. Otherwise (caking occurred), time-series temperature tended to decrease and the H2 and CO concentrations of product gas increased. Some adherent matters were identified on the surface of the char if caking occurred, whereas most of the functional groups disappeared from the char in the operation without occurrence of caking.
    Development and validation of cluster and EMMS drag model
    CHEN Cheng, QI Haiying
    2014, 65(6):  2003-2012.  doi:10.3969/j.issn.0438-1157.2014.06.008
    Abstract ( 814 )   PDF (918KB) ( 544 )  
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    Reasonable description of cluster parameters is significant for the development of drag model for heterogeneous gas-solids flows. This study proposed the cluster model for solids concentration in clusters and the cluster size based on theoretical analysis. The profile of cluster parameters with solids concentration had a peak locating between local solids concentration of 0.1 and 0.15, indicating largest heterogeneity there. The cluster model was validated directly by experimental data. Energy minimum multiscale method (EMMS) was improved by introducing the cluster model. The improved drag model agreed well with the experiment-based empirical model. Drag correction factors of both models first decreased and then increased with increasing solids concentration, and tended to unity at extremely small solids concentration close to zero and solids concentration at minimum fluidization. The improved drag model was coupled with the two-fluid model for simulations of gas-solids flows in CFB risers containing Geldart A and B particles. Heterogeneous solids distributions, local slip velocity, local heterogeneity and choking state were predicted and agreed well with experimental results, indicating the reasonability of the cluster and drag models.
    New two-scale hydrodynamic model based on energy balance in bubble column
    GUAN Xiaoping, WANG Lijun, LI Zhaoqi, ZHAO Yuanfang, CHENG Youwei, LI Xi
    2014, 65(6):  2013-2020.  doi:10.3969/j.issn.0438-1157.2014.06.009
    Abstract ( 683 )   PDF (4773KB) ( 406 )  
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    A new two-scale hydrodynamic model was proposed to describe large-scale motion and small-scale bubble wake turbulence. The large-scale shear induced turbulence was resolved by classical k-ε turbulence model, while the small-scale bubble wake turbulence was quantitively described by wake temperature transport equation. A wake pressure gradient source term was added to the motion equation to reflect the mutual influence between small scale turbulence and large scale fluid motion and to explain the mechanism of holdup non-uniform distribution in the bubble column. The model classified the energy dissipation into three kinds of mechanism: large-scale shear induced turbulence dissipation, small-scale wake turbulence dissipation, energy dissipation due to interaction between bubble wake and solid wall. The model well resolved the issue about energy balance. Simulation results agreed well with experiment data
    Relative viscosity of ethylene glycol-based nanofluids
    ZHOU Dengqing, WU Huiying
    2014, 65(6):  2021-2026.  doi:10.3969/j.issn.0438-1157.2014.06.010
    Abstract ( 997 )   PDF (5030KB) ( 489 )  
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    An experimental study was carried out on the viscosity of ethylene glycol (EG)-based nanofluids containing Al2O3, ZnO and CuO nanoparticles with the particle concentrations of 0.5%/3.0%/5.0%/7.0% (mass), respectively. Nanofluid samples were prepared by the two-step method without adding surfactant. The relative viscosity of EG-based nanofluids was not a strong monotonous function of temperature within 30-60℃. Nevertheless, the relative viscosity of EG-based nanofluids fluctuated with increasing temperature when mass fraction was high enough, with the fluctuation of ZnO (elongated)-EG nanofluid being more significant. It was also found that the relative viscosity of all the nanofluids tested increased with increasing volume fraction. Among them, CuO-EG increased most intensely while Al2O3-EG increased most moderately. Finally, a comparison analysis was made between the present experimental data and the prediction equations in literature.
    Modeling of clusters characteristics in circulating fluidized beds
    WANG Shuai, LIU Guodong, ZHAO Feixiang, ZHANG Qinghong, LU Huilin
    2014, 65(6):  2027-2033.  doi:10.3969/j.issn.0438-1157.2014.06.011
    Abstract ( 564 )   PDF (3270KB) ( 368 )  
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    Considering the multi-scale structure of the dense phase in the form of clusters and the dilute phase in the form of dispersed particles in the circulating fluidized bed, the relationship between accelerations and local structure parameters in the dense phase and dilute phase was established and the stability condition of the minimum energy dissipation by multi-scale drag force was proposed. Based on the bivariate extreme value theory, a cluster structure dependent (CSD) drag coefficient model was developed. Gas-solids flow behavior and cluster characteristics in risers were simulated using a two-fluid model. The concentrations of particles obtained by the CSD model showed better agreement with experimental results. Cluster diameter increased, reached a maximum and fell down to single particle diameter with increasing solids concentrations. In the simulation, the influence of accelerations of gas and particles could not be ignored because it appeared to be on the same order of magnitude as acceleration of gravity.
    Effect of drag model and restitution coefficient on gas-solids flow field in quick-contact cyclone reactors
    WANG Zhenbo, ZHANG Yuchun, XU Chunming
    2014, 65(6):  2034-2041.  doi:10.3969/j.issn.0438-1157.2014.06.012
    Abstract ( 731 )   PDF (1360KB) ( 377 )  
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    Gas-solids two-phase flow in a quick-contact cyclone reactor was simulated using a two-fluid model combining with kinetic theory of granular flow to study the effects of drag model and restitution coefficient on flow behavior. Three drag models, i.e. Gidaspow, Wen & Yu and Syamlal-O'Brien model were examined through comparing there effects on particle velocity vector, and radial distribution of particles. Compared with experimental data, it was found that the simulated results using Gidaspow model agreed well with the experimental data while Syamlal-O'Brien and Wen & Yu models showed relatively large errors. In addition, the simulated solids holdup was less than the experimental data when restitution coefficient was relatively small. When restitution coefficient was about 0.95, particles were distributed most uniformly and the simulated results fitted the best with experimental data.
    Resistance characteristics of micro pin fins with different cross-section shapes
    ZHANG Chengwu, PU Longmei, JIANG Guilin, GUAN Ning, LIU Zhigang
    2014, 65(6):  2042-2048.  doi:10.3969/j.issn.0438-1157.2014.06.013
    Abstract ( 741 )   PDF (1076KB) ( 541 )  
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    The de-ionized water, used as the working fluid, flowed through the channel fitted with staggered array of micro pin-fins in circular, diamond, and ellipse shapes and the resistance characteristics were investigated experimentally. The investigation shows that the pressure drop increases with the flux with these three micro pin-fin groups. When the flux is very small, ellipse and diamond shape micro pin-fin groups present almost the same pressure drop because the influences of the shape of micro pin-fin on the flow is weakened by the laminar boundary layer, while the flow resistance of circular pin fins is maximal due to the longer flow distance. The pressure drop of the ellipse shape micro pin-fin is minimal compared with other two shapes of pin fins when the Reynolds number is relatively large. At low Re, the friction factor of diamond shape micro pin-fins with the same major axis and minor axis as the ellipse shape micro pin-fins is slightly smaller than that of ellipse shape pin-fin. The study also shows that the calculation values from the correlation related to the diamond shape micro pin-fins agree with experimental data among the three shapes of micro pin-fins.
    Agglomeration characterization of THF and HCFC-141b hydrate particles
    LIU Haihong, LI Yuxing, WANG Wuchang, ZHANG Qingdong, ZHAO Pengfei, GAO Song
    2014, 65(6):  2049-2055.  doi:10.3969/j.issn.0438-1157.2014.06.014
    Abstract ( 727 )   PDF (1999KB) ( 347 )  
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    The objective of the present work was to research agglomeration characterization of tetrahydrofuran (THF) and HCFC-141b hydrate particles. Experimental hydrate particle size distributions (PSD) were compared to classical normal, log-normal, Gamma, Weibull distributions. The effects of initial THF and HCFC-141b solution concentration and stirring rate on the hydrate particles agglomeration were also studied. The particle characterizations of THF hydrate and HCFC-141b hydrate were compared. THF and HCFC-141b hydrate particle size distributions were in accordance with log-normal distribution. The lower the initial solution concentration and the greater the stirring speed, the smaller the hydrate particle size was, that is to say, this treatment could prevent particle agglomeration. HCFC-141b hydrate particles was approximately 1.3 times smaller than THF hydrate particles. HCFC-141b hydrate particles was easier to form slurry and more convenient for pipeline transportation.
    Numerical simulation of spray cooling for extruded plastic pipe
    LI Jing, ZENG Cheng, LIU Yeming, ZHANG Ding
    2014, 65(6):  2056-2062.  doi:10.3969/j.issn.0438-1157.2014.06.015
    Abstract ( 594 )   PDF (990KB) ( 428 )  
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    Cooling system is essential in the production process of extruded plastic pipe, which determines the length of production line and product quality. This study simulates the transient heat transfer of spray cooling based on ANSYS. The result shows that for the convective heat transfer coefficient less than 180 W·m-2·K-1, the time for cooling to 47℃ changes obviously with the convective heat transfer coefficient, while it does not change much for higher convective heat transfer coefficient. Then we simulate the spray nozzle based on FLUENT software, investigating the effect of entrance velocity and nozzle height on distribution of convective heat transfer coefficient. We have found that with other parameters constant, the total convective heat transfer coefficient increases with entrance velocity (within 6-15 m·s-1), and the heat transfer coefficient of stagnation point increases from 217 W·m-2·K-1 to 386 W·m-2·K-1. Wall convective heat transfer coefficient increases as the nozzle height decreases (within 68-128 mm), and heat transfer coefficient of stagnation point increases from 227 W·m-2·K-1 to 311 W·m-2·K-1. Finally we put forward a proposal on global optimization for spray cooling baths based on above study.
    Flow characteristics of grease in circular pipeline at varied temperatures
    PAN Jiabao, CHENG Yanhai, ZHU Zhencai, YANG Jinyong
    2014, 65(6):  2063-2069.  doi:10.3969/j.issn.0438-1157.2014.06.016
    Abstract ( 543 )   PDF (658KB) ( 275 )  
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    The effect of temperature on flow characteristics of NLGI 3 lithium grease in circular pipelines was investigated. The rheological behavior was examined by using rotational rheometer and the models for velocity and stress fields were established by combining the experimental results and theoretical analysis. The experimental results show that the lithium grease presents high yield shear stresses, excellent viscosity-temperature characteristics and shear-shinning behavior. The yield stress and viscosity decrease as temperature increases, improving the fluidity. The relationships between pipeline flow characteristics and influencing factors are given by using the mathematical model described through MATLAB programming and drawing. The effect of temperature on flow characteristics indicates that higher medium temperature is in favor of lithium grease transportation.
    Experimental investigation and model validation for liquid desiccant dehumidification and regeneration in falling-film plate
    QIAN Junfei, YIN Yonggao, PAN Xiongwei, ZHANG Xiaosong
    2014, 65(6):  2070-2077.  doi:10.3969/j.issn.0438-1157.2014.06.017
    Abstract ( 725 )   PDF (1553KB) ( 288 )  
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    To investigate the heat and mass transfer performance of liquid desiccant dehumidification/regeneration in falling-film plates, experiments were performed in the dehumidifier and regenerator using LiCl solution as the liquid desiccant. Effects of inlet air and solution parameters on their outlet parameters were examined experimentally. Empirical correlations coupling heat and mass transfer coefficients were presented, and the calculation results from NTU-Le heat and mass transfer model was compared with experimental data to verify the accuracy and suitability of the model. The results show that the error between simulation results and experimental data is within 10%, so that the NTU-Le model is suitable for the liquid desiccant dehumidification and regeneration in falling-film plates. The experimental results also provide reliable data for further analysis of heat and mass transfer performance between air and desiccant.
    Flow field structure with rigid-flexible impeller and rigid impeller
    LIU Zuohua, ZENG Qiqin, YANG Xianyan, LIU Renlong, WANG Yundong, TAO Changyuan
    2014, 65(6):  2078-2084.  doi:10.3969/j.issn.0438-1157.2014.06.018
    Abstract ( 780 )   PDF (4869KB) ( 523 )  
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    Isolated mixing region often appears in the high-viscosity fluid with laminar flow in a stirred vessel, reducing fluid mixing efficiency. Diminishing or eliminating isolated mixing region improves the mixing efficiency and reduces mixing energy consumption. Experimental and computational studies were carried out to compare the flow field structures with rigid Rushton turbine impeller (rigid RT impeller) and rigid-flexible Rushton turbine impeller (combination RT impeller). Analyses were carried out on axial, radial and tangential velocity vector plots, velocity contours and velocity distribution scatter plots at the same time power consumption (3 kW·m-3)with these two impellers. Results show that the energy concentrates at the tip of rigid RT impeller and the fluid velocity away from the impeller is small, even at 0 m·s-1, while for combination RT impeller, the energy distributes well in the stirred tank so that the fluid gains certain velocity everywhere. The numerical simulation results agree with experimental results. The combination RT impeller improves mixing efficiency by eliminating isolated mixing regions, while rigid RT impeller presents a poor mixing efficiency since isolated mixing regions always exist.
    Analysis on heat transfer process with temperature control by module type ice storage within confined space
    LIU Yingshu, JIA Yanxiang, SUN Shufeng, SONG Weixin
    2014, 65(6):  2085-2091.  doi:10.3969/j.issn.0438-1157.2014.06.019
    Abstract ( 602 )   PDF (2106KB) ( 331 )  
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    Aiming at the passive temperature control problem in confined spaces, we investigate the heat transfer and thermodynamic characteristics of module type ice temperature control process with mathematical models and experiments. A model for phase transition refrigeration by cool storage module is established, and with the mathematical expression for wall heat transfer coefficient, effective cooling time and cooling rate are derived. The relative error between the theoretical effective cooling time and experimental one is less than 5%. The results indicate that the wall heat transfer coefficient and cooling rate are proportional to environment temperature and relative moisture, and inversely proportional to cooling time. The correction factor equation for environment temperature and moisture is established and utilized for revising the mathematical models of storage module cooling rate and effective cooling time. These results provide important reference to the application of passive phase-transition refrigeration in confined space.
    Fine grid DEM simulation of bed layer height in bubbling fluidized-bed
    WU Guorong, OUYANG Jie
    2014, 65(6):  2092-2097.  doi:10.3969/j.issn.0438-1157.2014.06.020
    Abstract ( 818 )   PDF (1395KB) ( 294 )  
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    For fine-grid DEM simulation of gas-solids fluidized-bed, the traditional methods of calculating grid porosity and local porosity lead to large deviations in simulation results. This paper gives a precise area fraction model and a completely circumstance-dependent local porosity model to more properly calculate grid porosity and local porosity, respectively. These models were validated by the DEM simulation test on a small-scale bubbling fluidized system, using fine-grid size of two particle diameters. The simulated bubble shape and size were close to the measurement. Simulations showed that DEM could perform well in modeling time-varying waveforms for the bed layer height, when using the precise area fraction model and the local porosity model.
    Preparation of V2O5/TiO2 catalyst with in-situ sol-gel method for denitration in wide temperature window
    GUO Feng, YU Jian, CHU Mo, XU Guangwen
    2014, 65(6):  2098-2105.  doi:10.3969/j.issn.0438-1157.2014.06.021
    Abstract ( 610 )   PDF (791KB) ( 589 )  
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    A series of V2O5/TiO2 catalysts with different amounts of V2O5 were prepared with the in-situ sol-gel method. Characterization of the catalysts were performed with N2 adsorption and desorption, X-ray diffraction (XRD), UV-Vis spectroscopy (UV-Vis) and temperature programmed desorption of NH3(NH3-TPD). All catalysts exhibited mesoporous structure, high dispersion of V2O5 on the surface of TiO2 and three typical acid sites. Evaluation of the catalytic performance for NH3-denitration revealed good activity for low-temperature denitration of the catalyst, which increased with increasing amount of V2O5. The V2O5/TiO2 catalyst with 10% (mass) V2O5 showed the widest temperature window of 200-450℃ for NO conversions of about 80% at a NH3/NO ratio of 0.8. The catalytic performance for denitration did not obviously decrease in a 20 h continuous denitration test at 240℃ for the simulated flue gas containing 0.06% (vol) SO2 and 10% (vol) H2O. The UV-Vis analysis clarified that for NH3-denitration the unimer and low-poly vanadates are the active components of the prepared V2O5/TiO2 catalysts.
    n-Butyraldehyde aldol self-condensation catalyzed by H4SiW12O40/SiO2
    CHEN Cuina, LIU Xiaohong, AN Hualiang, ZHAO Xinqiang, WANG Yanji
    2014, 65(6):  2106-2112.  doi:10.3969/j.issn.0438-1157.2014.06.022
    Abstract ( 972 )   PDF (640KB) ( 669 )  
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    Aldol self-condensation of n-butyraldehyde to 2-ethyl-2-hexenal is one of the important processes for industrial production of 2-ethyl hexanol. Firstly, the catalytic performance of H3PW12O40, H4SiW12O40 and H3PMo12O40 was evaluated and the results showed that H4SiW12O40 presented the best catalytic activity. Secondly, supported H4SiW12O40 catalysts were prepared with the impregnation method and the influence of the kind of support and preparation process parameters on catalyst performance was investigated. The suitable preparation conditions were determined as follows: taking SiO2 as support, loading of H4SiW12O40= 50% (mass), calcination temperature of 150℃ and calcination time of 2 h. The effect of reaction conditions on the catalyst performance of H4SiW12O40/SiO2 was also studied and the suitable reaction conditions was determined as follows: mass ratio of catalyst to n-butyraldehyde 0.15, reaction temperature of 120℃ and reaction time of 6 h. Under the above conditions, the conversion of n-butyraldehyde and the selectivity to 2-ethyl-2-hexenal were 90.4% and 89.2%, respectively. However, the reusability of H4SiW12O40/SiO2 catalyst was poor. Analysis of ICP-AES and XRD demonstrated that the loss of active species H4SiW12O40 was the main reason. In order to decrease the loss of H4SiW12O40, H4SiW12O40/SiO2 catalyst was prepared with the sol-gel method using [emim]BF4 ionic liquid as template. The activity test result showed that the reusability of the prepared catalyst was improved to some extent.
    Effect of Fe/Co mass ratio on activity of non-noble metal catalyst for oxygen reduction reaction
    ZHANG Yuhui, YI Qingfeng
    2014, 65(6):  2113-2119.  doi:10.3969/j.issn.0438-1157.2014.06.023
    Abstract ( 637 )   PDF (2083KB) ( 350 )  
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    Transition metal has an important effect on the electrocatalytic activity of non-noble metal catalysts for oxygen reduction reaction (ORR). In this work, the precursor containing MWCNTs, polyaniline, Fe and Co was firstly synthesized, and then the precursor was heated at 900℃ under N2 to obtain the C-N catalysts with different Fe/Co mass ratios. The structure of the catalysts was investigated with SEM and X-ray diffraction. ORR activity of the catalysts in acidic and alkaline media was tested with voltammetry. The prepared catalyst with Fe/Co mass ratio of 6:1 presents the highest electrocatalytic activity for ORR. ORR current density at 2000 r·min-1 was 12.5 mA·mg-1@-0.3 V(vs SCE) in acidic solution and 7.8 mA·mg-1@-0.8 V(vs SCE) in alkaline solution, and onset potential of ORR was 0.52 V(vs SCE) in acidic solution and-0.09 V(vs SCE) in alkaline solution. Fe/Co mass ratio played a great role in the electrocatalytic activity of these non-noble metal catalysts for ORR.
    Selection and separation performance of ionic liquid as additive in butadiene extraction with ACN
    ZENG Shaojuan, TIAN Xiao, DONG Haifeng, ZHANG Xiangping, ZHANG Suojiang
    2014, 65(6):  2120-2129.  doi:10.3969/j.issn.0438-1157.2014.06.024
    Abstract ( 1146 )   PDF (1037KB) ( 319 )  
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    A new separation process of C4 mixture with ionic liquid as additive was proposed. The influence of ionic liquid on the relative volatility of C4 mixtures in acetonitrile (ACN) solvent system was investigated. The interaction mechanisms between ACN, ionic liquid and C4 were analyzed by quantum chemistry calculations. In addition, two flowsheets of ACN butadiene extraction process with or without ionic liquid were simulated. Ionic liquids were proved to be effective additives for C4 separation, and the appropriate ionic liquid [Emim][PF6] for ACN butadiene extraction process was chosen and confirmed by the simulation results. In the practical process, the mixed solvent of ACN with ionic liquids showed better separation performance than that of ACN solvent, and the new technology could recover more than 98%(mass) ionic liquids after the distillation process. Moreover, separating C4 with ionic liquid could decrease energy consumption by about 24%. Therefore, the proposed new process technology with ionic liquid as additive is a perspective C4 mixture separation process.
    Extracting magnesium from ascharite by vacuum thermal reduction using calcium carbide as redutant
    WANG Yaowu, PENG Jianping, LI Yinglong, ZHAO Kun, SONG Yang, FENG Naixiang
    2014, 65(6):  2130-2136.  doi:10.3969/j.issn.0438-1157.2014.06.025
    Abstract ( 585 )   PDF (655KB) ( 295 )  
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    A method separating magnesium and boron from ascharite by vacuum thermal reduction using calcium carbide as redutant was studied experimentally. The reason that led to low reduction ratio of MgO in the vacuum thermal reduction process was researched by phase analysis of calcined ascharite and the influencing factors were analyzed. The results show that magnesium in the calcined ascharite is mainly involved in magnesium borate and magnesium silicate, reduction of which is difficult and only small amount is free state of MgO, which is the main cause of low reduction ratio. The addition of CaO during calcination of ascharite can promote formation of more free state MgO and reduction of more MgO. As long as enough CaO is added, magnesium and boron can be effectively separated and reduction rate can be over 85%. The main phases in reduction slag are CaO and 3CaO·B2O3. The reduction slag can be used as raw material for production of alkali free glass fiber. So the comprehensive utilization of ascharite ore can be realized.
    Influence of fiber on filtration performance for PM2.5
    GU Conghui, LÜ Shiwu, LI Rui, LU Duanfeng, WU Wentao, YUAN Zhulin
    2014, 65(6):  2137-2147.  doi:10.3969/j.issn.0438-1157.2014.06.026
    Abstract ( 978 )   PDF (4912KB) ( 371 )  
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    With the rapid development of industrialization, a large number of toxic residues of PM2.5 are produced in the daily life. Due to its slow settling velocity and large quantity and surface area, PM2.5 is a carrier of pollutants and damages the respiratory function of body. It is important to study how to effectively remove PM2.5 in industrial production and daily life. The filtration performance of fibers with different sizes of Y-shaped and circular section is examined in this study, and the relation of particle retention to smoke speed and particle concentration is analyzed. The influence of density and porosity of fiber assembly on the filtration performance of PM2.5 is studied. Fiber and fiber assembly are simulated with Euler method and Lagrange method, and the numerical results are in good agreement with experimental data. The results on Y-shaped fiber show that higher linear density of fiber retains less particles at the same smoke speed and concentration, higher particle concentration leads to higher particle retention at the same linear density and speed, and higher speed of smoke gas gives higher particle retention at the same linear density and concentration. The retention with Y-shaped fiber section is better than that with circular section. The results on fiber assembly show that higher linear density of fiber improves the particle retention at the same porosity and larger porosity reduces the retention at the same linear density of fiber. The performance for PM2.5 filtration is better at linear density of fiber of 0.27 tex and fiber assembly porosity of 0.88.
    Adsorption of Cu2+ by anionic β-cyclodextrin/Fe3O4 magnetic microspheres
    LI Kaibin, SHEN Yiding, FEI Guiqiang, LI Zhongjin
    2014, 65(6):  2148-2155.  doi:10.3969/j.issn.0438-1157.2014.06.027
    Abstract ( 1027 )   PDF (928KB) ( 657 )  
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    Anionic b-CD/Fe3O4 magnetic microspheres (b-CDM) were prepared by modified b-cyclodextrin. The adsorption thermodynamics, kinetics and recycle about the adsorption of Cu2+ by b-CDM were studied. With a mathematical fitting method, adsorption thermodynamic and kinetic parameters were obtained, and adsorption mechanism was discussed. Thermodynamic studies show that the adsorption of Cu2+ by b-CDM is spontaneous and it is an exothermic process. Further study indicates that it is appropriate to use Langmuir and Freundlich isothermal adsorption models to study the adsorption process. Kinetic study shows that the adsorption of Cu2+ by b-CDM is a process consisting of three stages, which are external diffusion, pore diffusion and adsorption reaction. Both physical adsorption and chemical adsorption take place. The value of apparent adsorption activation energy is 24.12 kJ·mol-1. At adsorption temperature of 298 K, 308 K, and 318 K, the adsorption rate constants are 0.0906, 0.1161, 0.1674 g·mmol-1·min-1, respectively. As the equilibrium absorption capacity of Cu2+ increases, the driving force of adsorption varies from enthalpy change to entropy change. After b-CDM was reused for 8 times, the removal rate declined from 95.20% to 88.21%.
    Optimal design of multistream heat exchanger network based on state space superstructure
    LI Yongqiang, WANG Bing, ZOU Xiong, DONG Hongguang, YAO Pingjing
    2014, 65(6):  2156-2164.  doi:10.3969/j.issn.0438-1157.2014.06.028
    Abstract ( 557 )   PDF (769KB) ( 302 )  
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    Multistream heat exchanger (MHEX) has attracted attention in the process intensification field with its compact structure, high efficiency and low heat loss. However, the potential advantages of its process and equipment are still worth discussing. An improved State-space superstructure based on MHEXs process operator (PO) was proposed to convert the network synthesis into a super-exchanger design. Hierarchy matching MHEXs PO was constructed, and the strict heat transfer calculation among multiple streams was implemented through temperature coordinated effect between adjacent streams. Arbitrary splitting and mixing of any stream was achieved by corresponding mixers and splitters in distribution network (DN). The objective function was ameliorated by taking heat loss into consideration. Through introducing the cost of heat loss and thermal insulation material, the external surface envelope advantage of MHEX was presented clearly owing to coverage between adjacent heat-transfer surfaces. Then, a corresponding nonlinear programming (NLP) mathematical model was formulated for generating the optimal design of MHEXs network while synthesizing the utilities, equipment investment, heat loss and thermal insulation material simultaneously. At last, four case studies were performed to verify the feasibility and superiority of the methodology.
    Convergence depth control based polynary hybrid nonlinear programming algorithm
    CHEN Weifeng, SHAO Zhijiang
    2014, 65(6):  2165-2171.  doi:10.3969/j.issn.0438-1157.2014.06.029
    Abstract ( 434 )   PDF (1103KB) ( 452 )  
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    With the improvement of systematicness and integrality of the object model description, the complexity of process optimization problem is increased and then higher requirements are put forward for the performance of optimization algorithm. The existing nonlinear programming algorithms have both merits and demerits in their solving performance. A convergence depth control based polynary hybrid nonlinear programming algorithm was proposed in this paper. Each nonlinear programming algorithm was regarded as a meta-algorithm. In order to take full advantage of each meta-algorithm, convergence depth was used to control interactive cooperation among them and then the ability for solving large-scale complex optimization problem could be enhanced. Data reconciliation problem of air separation system and optimization problem of depropanizer and debutanizer distillation column systems were taken to test the proposed algorithm. The numerical results showed that the solving ability of the polynary hybrid nonlinear programming algorithm was better than the single nonlinear programming algorithm.
    Fault tree analysis on decreases of desalination rate and permeate flow rate of seawater reverse osmosis desalination system
    JIANG Zhoushu, WENG Xiangbin, WANG Jian, LEI Chunzheng
    2014, 65(6):  2172-2178.  doi:10.3969/j.issn.0438-1157.2014.06.030
    Abstract ( 652 )   PDF (1919KB) ( 458 )  
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    Fault tree analysis (FTA) is a deductive fault diagnosis, which has been successfully applied in such areas as the assessment of reliability of nuclear reactors and spacecrafts. Currently reverse osmosis (RO) is the most widely used seawater desalination methodology. The decline of both desalination rate and permeate flow rate is considered the most typical type of fault which causes significant loss in the seawater reverse osmosis (SWRO) system. Based on an in-depth analysis of the component structure and operational principle of the seawater reverse osmosis membrane, this paper manages to work out the fault tree of the decline of desalination rate and permeate flow rate. With the help of Boolean algebra, the minimal cut sets and minimal path sets were successfully established, and the analysis of the importance of basic events structure was finally completed. This research provides a set of scientific and practical methods for the construction of the knowledge base in the SWRO fault diagnosis expert system.
    Pinch point after introducing regeneration process in regeneration recycling water systems
    ZHANG Yunxi, FENG Xiao, LIU Guilian
    2014, 65(6):  2179-2185.  doi:10.3969/j.issn.0438-1157.2014.06.031
    Abstract ( 432 )   PDF (820KB) ( 282 )  
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    The optimal water system with regeneration recycling can minimize freshwater consumption and wastewater discharge to the largest extent, and thus it has drawn much attention in academic and industrial circles. After introducing the regeneration process in a water-using system, the limiting water supply line will be changed, causing the possible change of the location and number of pinch points. Based on prior approach to constructing the optimal water supply line in regeneration recycling water systems, the influence factors on the change of pinch point when introducing the regeneration process were analyzed, such as the position and concave degree of concave points on the limiting composite curve and the flowrate relationship of the stream with highest concentration and freshwater. The change of the position and number of pinch points could be obtained, providing theoretical guidance for analysis and design of water-using networks.
    Preparation and application of GR/PANI composite anode for MFC
    HE Haibo, WANG Xuyun, BAI Lijun, GUO Qingjie
    2014, 65(6):  2186-2192.  doi:10.3969/j.issn.0438-1157.2014.06.032
    Abstract ( 788 )   PDF (3527KB) ( 407 )  
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    Graphene (GR) was synthesized from natural graphene powder by chemical oxidation-reduction method. Graphene/polyaniline (GR/PANI) film anode was prepared by electrochemical modification and used in fixed-bed microbial fuel cell (MFC) to examine the electrochemical performance of the prepared anodes. The prepared anodes were characterized by IR spectrum, X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM), respectively. The electrochemical properties were studied by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Polyaniline evenly attached to graphene and GR/PANI film electrode had good reversibility, small resistance and good electrical conductivity. When the GR/PANI film anode was used in MFC, maximum output power density and open circuit voltage were up to 230.2 mW·m-2 and 834.6 mV respectively, 110.6% and 34.8% higher than those of unmodified anode. The resistance of GR/PANI film anode also decreased from 843.2 Ω of the unmodified anode to 469.4 Ω. The experiment results indicated that, the GR/PANI composite was an excellent electrode material, and the MFC with GR/PANI film anode showed good electricity production performance.
    Direct electrooxidation synthesis of anisaldehyde dimethyl acetal in a quasi capillary gap cell
    WANG Ming, XU Yinghua, DING Xufen, MA Chun'an
    2014, 65(6):  2193-2201.  doi:10.3969/j.issn.0438-1157.2014.06.033
    Abstract ( 836 )   PDF (2481KB) ( 376 )  
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    The influences of anodic electrode material,supporting electrolyte and current density on the direct electrochemical oxidation synthesis of anisaldehyde dimethyl acetal (p-MBDMA) in a quasi capillary gap cell were investigated by the galvanostatic method. The electrochemical behavior of p-methoxytoluene (p-MT) and p-MBDMA in methanol was studied with linear sweep voltammetry. The experimental results showed that graphite as anodic material revealed good electrochemical catalytic activity to the oxidation of p-MT. The p-MBDMA yield of four anodic materials decreased in the following order:graphite > Ir-Ta/Ti > Ru-Ir/Ti > Pt/Ti and six supporting electrolytes followed the decreasing order:sodium p-toluenesulfonate > sodium benzenesulfonate > potassium fluoride > sodium methoxide > sodium perchlorate > sodium 3-nitrobenzenesulfonate. With current density varying from 1 to 9 A·dm-2,reaction selectivity decreased with increasing current density. Furthermore,a proper amount of addition of 2,6-lutidine could improve the selectivity by avoiding further oxidation of p-MBDMA. Under the optimized conditions of 0.8~1.0 mol·L-1 p-MT,1.0% (mass) sodium p-toluenesulfonate as supporting electrolyte and addition of 0.5% (mass) 2,6-lutidine,yield and current efficiency could reach 75% and 47% respectively. During the process of electrolysis,current density changed from 3.0 to 2.0 A·dm-2 at 0.8 Q* and the operating condition was under the electrolyte solution flow rate of 20 L·h-1 at temperature 40℃. The research provided an important basis for commercialization of electrochemical oxidation synthesis of p-MBDMA.
    Comparison on seal performance of liquid-lubricated end face seals with different shapes inclined dimples
    SHE Baoying, PENG Xudong, MENG Xiangkai, LI Jiyun
    2014, 65(6):  2202-2210.  doi:10.3969/j.issn.0438-1157.2014.06.034
    Abstract ( 575 )   PDF (1830KB) ( 253 )  
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    The directionality of surface dimples can guide the direction of fluid flow in the seal gap and produce fluid cumulative effect in the dimple length direction, which leads to obvious hydrodynamic effect. As a result, the seal faces separate and full film lubrication is formed. The textured mechanical face seals with different dimple shapes, such as circle, diamond, ellipse and rectangle were studied. Based on the mass-conserving JFO cavitation algorithm, a mathematical model was presented by taking the cavitation of liquid fluid between the two seal faces into consideration. The Reynolds equation was solved by use of the finite difference method, and pressure distribution was obtained. Comparative analysis of mechanical face seal performance with different dimple shapes at different operating parameters and geometric parameters was presented. The results showed that inclined dimple displayed better hydrodynamic effect than circle dimple under low speed or high pressure condition. The rectangle dimple showed the best hydrodynamic effect, and the diamond dimple had a lower leakage. Excellent hydrodynamic effect could be obtained for inclined dimple with different shapes when film thickness h0=1.5-2.5 mm, pore depth hp=2-3 mm, axial ratio γ=3-4, opponent texturing proportion β=0.5, inclination angle α1=30°-50° and α2=120°-140°.
    Influence of KF on cathodic process for Na3AlF6-Al2O3 molten salt electrolysis
    TAO Shaohu, DI Yuezhong, PENG Jianping, WANG Yaowu, LIU Kejia, FENG Naixiang
    2014, 65(6):  2211-2218.  doi:10.3969/j.issn.0438-1157.2014.06.035
    Abstract ( 714 )   PDF (782KB) ( 291 )  
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    The electrochemical behavior of cathodic process was investigated by means of cyclic voltammetry, electrochemical impedance spectroscopy and square wave voltammetry in both Na3AlF6-Al2O3 and Na3AlF6-Al2O3-KF systems. The results showed that the reduction peaks shifted negatively and oxidation peak shifted positively with the increase of scan rate from the measurement of cyclic voltammetry. The reaction process was irreversible under the condition of lower scan rate, and the reaction was relatively flat and stable, but the reduction process became reversible gradually with the increase of scan rate. Because of polymerization phenomenon at the electrode-site, inductance phenomenon appeared in the high frequency area when KF was absent in the molten salt. Under the condition of containing KF, the reaction was predominantly controlled by charge transfer and diffusion. The growth of the concentration of KF could decrease diffusion impedance coefficient and increase reaction current. The charge transfer process gradually replaced the diffusion process and accelerated oxidation rate. Meanwhile the reduction and oxidation process became reversible. Adding KF also suppressed the deposition of aluminum and alloying effect was obvious. Through Gaussian fitting for the cathodic prewave, electron transfer numbers of Al ion were 1.19, 1.02 and 0.75 in different systems of KF concentration(0,3%,5%)respectively.
    Stability of carbon dioxide foam and effect of polymer on its foam properties
    LÜ Mingming, WANG Shuzhong
    2014, 65(6):  2219-2224.  doi:10.3969/j.issn.0438-1157.2014.06.036
    Abstract ( 593 )   PDF (488KB) ( 359 )  
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    Considering the special nature of CO2 and the behavior of CO2 foam in the porous medium different from foams of other gases, CO2 foam stability, decay property of CO2 foam and effect of partially hydrolyzed polyacrylamide (HPAM) on CO2 foam properties were studied. The gas-flow method was used for foaming and sodium dodecyl benzene sulfonate (SDBS) was used as the foaming agent. The stability of CO2 foam was worse than that of N2 foam under the same conditions and was nearly not influenced by surfactant concentration. Besides, the decay curve of CO2 foam was approximately a straight line and the volume of CO2 foam decreased rapidly after foaming. An important factor leading to the poor stability of CO2 foam lay on the large film permeability coefficient because of higher solubility of CO2 in water, which further led to the different propagation behavior of CO2 foam from N2 foam in the core. The adding of polymer HPAM enhanced the stability of CO2 foam to a certain extent, but reduced the foaming property of surfactant solution. Therefore, both foam stability and foaming property of surfactant solution should be considered to determine the optimal concentration of polymer in the actual application.
    Batch butanol fermentation using mixed sugars of glucose and fructose with oxidoreduction potential control
    ZHANG Xu, WU Youduo, QI Gaoxiang, LIU Chenguang, CHEN Lijie, BAI Fengwu
    2014, 65(6):  2225-2231.  doi:10.3969/j.issn.0438-1157.2014.06.037
    Abstract ( 713 )   PDF (670KB) ( 380 )  
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    Butanol production and sugar utilization were greatly improved via oxidoreduction potential (ORP) control strategy during batch acetone-butanol-ethanol (ABE) fermentation with less acids accumulation. Batch fermentations using mixed sugars of glucose and fructose were conducted by pumping sterile air into the fermentor to control ORP above-490,-460,-430 and-400 mV, respectively. When ORP was controlled above-460 mV, butanol production and total solvents reached 13.19 g·L-1 and 19.71 g·L-1, respectively, increased by 139.38% and 117.07% compared to the uncontrolled process. At the end of fermentation, residual sugars concentration dropped to 3.2 g·L-1 and sugar utilization was as high as 94.18%. The results showed that the ORP-control strategy significantly improved sugar utilization, especially for fructose, and butanol production from mixed sugars, indicating that ORP-control could show a stimulatory effect on ABE fermentation and would be an economically competitive strategy for improving fermentation efficiency.
    Influence of additives on NOxOUT denitration and formation of N2O and CO
    ZHOU Hao, ZHANG Zhizhong, BAO Qiang, LIU Jiancheng, CEN Kefa
    2014, 65(6):  2232-2240.  doi:10.3969/j.issn.0438-1157.2014.06.038
    Abstract ( 1131 )   PDF (956KB) ( 578 )  
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    An experiment was performed to study the removal of NOx pollution and formation of greenhouse gas (N2O) and CO in NOxOUT process. Kinetic analysis was combined with the experiment results to discuss the effect of additives. The optimum reaction temperature was 950℃ and the highest denitration efficiency could reach 76.33% with different normalized stoichimetric ratios (NSR). The formation curves of N2O with temperature were similar to the efficiency curve and N2O emission reached a peak value at the temperature around 950℃. Increasing NSR and O2 concentration made N2O emission level higher. N2O emission first increased and then decreased with increasing residence time at higher temperatures (950℃,1000℃). Sodium carbonate, sodium acetate, sodium glutamate and ethanol could effectively improve the denitration efficiency on the low temperature side and extend corresponding temperature window, especially obviously for sodium glutamate. Denitration efficiency was related to temperature when altering the concentration of sodium salts and the optimum addition amount was 60 ml·L-1 for sodium atom. Above-mentioned additives could all remarkably reduce the emission of N2O and CO at medium and high temperatures, but adversely at the end point of low temperature. N2O and CO emission presented respective variation trends with the differences of temperature, type and concentartion of additives.
    Performance analysis of pressurized absorption thermal storage equipment
    ZHANG Xiaoling, SHI Wenxing, WANG Baolong, LI Xianting
    2014, 65(6):  2241-2248.  doi:10.3969/j.issn.0438-1157.2014.06.039
    Abstract ( 591 )   PDF (777KB) ( 304 )  
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    Due to its high thermal storage density and little heat loss, absorption thermal energy storage (ATES) is known as a potential thermal energy storage technology. However, current equipment has poor absorption ability and suffers from low efficiency. In this paper, a pressurized absorption thermal storage technology is proposed and the principle is introduced. Effects of pressurization on the thermodynamic performance are analyzed under different operating conditions. The results indicate that the utilization of pressurization can largely enhance the coefficient of performance of ATES system when the evaporating and generating temperatures are low and condensing temperature is high. Comparing with the absorption storage cycle without pressurization, a cycle with pressurization can increase the energy storage density by 30%-295% at the pressure ratio of 3.
    Reduction of nitric oxide in flue gas by coal char
    FANG Xiaoqing, FAN Chuigang, DU Lin, SONG Wenli, LIN Weigang, LI Songgeng
    2014, 65(6):  2249-2255.  doi:10.3969/j.issn.0438-1157.2014.06.040
    Abstract ( 801 )   PDF (669KB) ( 409 )  
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    NO reduction by coal char was investigated in a fixed bed reactor using a simulated flue gas. Two different operation modes(programmed temperature and constant temperature) were employed to explore the mechanism of NO removal by coal char and to study the effects of the variables on NO removal efficiency and selectivity including temperature, coal type, NO and oxygen concentrations in flue gas and space velocity. The results indicated that surface complexes formed by chemisorption of NO and O2 on carbon active sites played the key role in reactions between C-NO and C-O2. XLHT coal char showed both the highest rate of NO reduction and C-NO selectivity among the coal chars studied. NO reduction by XLHT coal char could reach 99% at 723 K. Under the experimental conditions in this work, an increase in temperature and/or oxygen concentration in flue gas enhanced NO reduction. However, C-NO selectivity decreased with the increasing O2 concentration. Higher NO concentration in flue gas led to lower NO reduction but higher C-NO selectivity.
    Effect of carrier gas flow rate and heating rate on thermal desorption of polychlorinated biphenyls in contaminated soil
    BAI Sihong, CHEN Tong, QI Zhifu, LIU Jie, LU Shengyong, BO Zheng, LI Xiaodong
    2014, 65(6):  2256-2263.  doi:10.3969/j.issn.0438-1157.2014.06.041
    Abstract ( 854 )   PDF (1038KB) ( 469 )  
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    A real soil contaminated by high concentration polychlorinated biphenyl (PCBs) was heated in a tube furnace at various carrier gas flow rate and at various heating rate to investigate their effect on thermal desorption of PCBs in contaminated soil. With the rising of carrier gas flow rate, a slight increase of PCBs removal efficiency (from 93.5% to 95.1%) and toxic equivalency quantity (TEQ) in soil were observed. With increase of the flow rate desorption amount of PCBs was obvious large when it was lower than 400 ml·min-1, then a little chang at >400 ml·min-1, while TEQ of PCBs showed a trend of linear increase with the rising of flow rate. The TEQ of polychlorinated dibenzo-p-dioxin/dibenzofuran (PCDD/Fs) in treated soil decreased, while in carrier gas a large increase of TEQ of PCDD/Fs especially PCDFs was observed.The removal rate of PCBs in soil showed a significant positive linear relationship with the heating rate. With the rising of heating rate, the removal efficiency of PCBs in soil increased, and the TEQ of PCBs had a little change. The desorption amount of PCBs decreased. The TEQ removal efficiency of PCDD/Fs increased. After thermal desoption there was significant formation of PCDD/Fs while there was TEQ high increase of PCDD/Fs. Generally, the effect of flow rate on the removal efficiency of PCBs in soil was less but on the desorption amount of PCBs was significant. Higher heating rate can make a better removal efficiency of PCBs and lower formation of PCDD/Fs.
    Characteristics of ammonia oxidation in low-temperature combustion
    CAO Qingxi, LIU Hui, WU Shaohua, WU Dongyang, YANG Chunhui
    2014, 65(6):  2264-2269.  doi:10.3969/j.issn.0438-1157.2014.06.042
    Abstract ( 1094 )   PDF (633KB) ( 1212 )  
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    Low-temperature combustion, such as combustion of solid fuels (low-rank coals, biomass etc.) in grate furnaces or fluidized bed combustors, can make NH3 (fuel-nitrogen) conversion, which is an important source of NOx and N2O. To understand deeply on NH3 oxidation and production of nitrogen oxides in low-temperature combustion process, the effect of combustible gases (CO, CH4, or H2) and NO on ammonia oxidation reaction was experimentally investigated in a tubular flow reactor at temperature range 600-1000℃, and the concentrations of NO, NO2, NH3, CO, CH4 and O2 were monitored continually with online Fourier-transformed infrared gas analyzer (Gasmet DX-4000). The results obtained were analyzed to clarify the chemical reaction mechanism. It was found that trace amounts of CO, CH4, or H2 could promote the oxidation of ammonia and enhance the emissions of NOx and N2O significantly under the condition of low temperature and oxidizing atmosphere. At equal concentration, the effect of H2 on ammonia oxidation was the greatest, following was CH4 and CO. As concentration increase of the combustible gas, the ammonia concentrations in combustion product decreased and approached rapidly zero, while the emissions of NOx and N2O increased firstly and then arrived at a stable value. When there was NO in initial gas mixture, oxidation reaction of ammonia could be enhanced too.
    Calculation of hydrate formation probability in wet-gas pipelines
    DENG Daoming, TU Duoyun, DONG Yong, GENG Lin, GONG Jing
    2014, 65(6):  2270-2275.  doi:10.3969/j.issn.0438-1157.2014.06.043
    Abstract ( 884 )   PDF (605KB) ( 431 )  
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    Formation ofhydrate in wet-gas pipelines could bring potential safety hazard. Flow safety evaluation of wet-gas pipelines is of importance for guaranteeing production safety and minimizing losses. The first step of this evaluation is to calculate the probability of hydrate formation(HFP) in wet-gas pipeline. In this work, based on the reliability limit state method and the calculation of the hydraulics and thermodynamics for wet-gas pipeline, and using the water content in sour natural gas predicted by higher precision Har-PR and the conditions of hydrate formation estimated by Chen-Guo model, a probability limit state equation is established from the difference of temperature of hydrate formation and actual flow in the pipeline, and the probability of hydrate formation(FHP) in pipelines is calculated by combined probability method. The entrance data in the experimental hydrate flow loop is analyzed, and the results show that there is the Gaussian distribution for inlet pressure and temperature and the largest extreme value distribution for the inlet flow rate. A case calculation demonstrates that:(1)all mean values and standard deviations of random variables affect HFP in wet gas pipelines; (2)the sensibility of the HFP is different for different random process variables; (3)the probability of hydrate formation in entire pipeline is affected by both the sample numbers for single and combined random variables.
    Removal mechanism of emulsified oil in wastewater by biologic materials modified with lauric acid
    CHEN Yuefang, JI Zhen, LIN Hai, DONG Yingbo
    2014, 65(6):  2276-2284.  doi:10.3969/j.issn.0438-1157.2014.06.044
    Abstract ( 831 )   PDF (7974KB) ( 352 )  
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    Oil pollution results in detrimental effects on the environment, living organisms and economy. Currently, a lot of attempt is devoted to provide an efficient, easy and cheap method for cleaning-up oil pollution. To improve the efficiency cleaning-up emulsified oil in wastewater, lauric acid was employed to modify corn cob and peanut shell, and these materials were characterized by scanning electron microscope (SEM), Brunauer-Emmett-Teller (BET) method and Fourier transform infrared spectrometer (FTIR). The results indicate that the modification of lauric acid is taken place by the esterification reaction between carboxyl in lauric acid and hydroxyl in cellulose, hemicellulose and lignin of biologic materials, and ester group formed is connected to alkyl chain, not only increasing the oleophylic and decreasing hydrophobic property of absorbents, but also creating micro-porosity. So, it can be expected that if the modified materials are employed for removal of emulsified oil, the oil adsorption capacity can be enhanced, because of the combined action of alkyl chain and micro-pore. In order to measure the removal efficiency of emulsified oil, in the present study, petroleum ether is used to extract oil from water sample, and ultraviolet spectroscopy employs for measuring oil concentration. The results show that the oil adsorption capacity is 6.86 mg·g-1 and 5.21 mg·g-1 for raw corn cob and peanut shell, and goes up 10.79 mg·g-1 and 7.44 mg·g-1 for the modified samples by lauric acid, respectively. Therefore, when biologic materials modified by lauric acid are applied to treat emulsified oily water, not only removal efficiency is high, but also the waste is controled by another waste. It is a very environmental protection measure.
    Numerical study on absorption of carbon dioxide and mass transfer performance in hollow fiber membrane contactor
    ZHANG Li, JU Shunxiang, YAN Yunfei, ZHANG Zhi'en
    2014, 65(6):  2285-2293.  doi:10.3969/j.issn.0438-1157.2014.06.045
    Abstract ( 898 )   PDF (1377KB) ( 322 )  
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    A type of process, which absorbs carbon dioxide (CO2) from flue gas in hollow fiber membrane contactor, has been considered as one of clean, high efficient and the most promising decarburization technologies. A two-dimensional mathematical model was developed for absorption of CO2 from parallel countercurrent mixed gas by hollow fiber membrane contactor. By using finite element method, CO2 removal(decarburization) and mass transfer performance of three absorbents EEA(ethyl-ethanolamine), EDA(ethylenediamine) and PZ(piperazine) were simulated at various operation conditions in which axial and radial diffusion in membrane contactor as well as diffusion in fiber and membrane pores and non-wetting condition were considered. The simulation results show that the order of decarburization performance is PZ > EDA > EEA. The influence of the gas phase parameters on CO2 removal and mass transfer is more significant than that of liquid phase parameters. With increase of gas flow rate, CO2 concentration, and gas temperature, the decarburization efficiency decreases. While the CO2 removal efficiency goes up when liquid flow rate, solvent concentration, and liquid temperature increase. However, the CO2 mass transfer rate speeds up with increase of all parameters except gas temperature. So, the suitable control of liquid parameters is required, which are not over high to prevent adverse effects on CO2 absorption.
    Effect of hydraulic retention time on nitrogen and phosphorus removal by biofilm and granular coupling process
    YIN Hang, HE Li, LU Jiancong, GAO Hui, GAO Dawen
    2014, 65(6):  2294-2300.  doi:10.3969/j.issn.0438-1157.2014.06.046
    Abstract ( 615 )   PDF (760KB) ( 247 )  
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    In home-designed coupling unit consisting of suspended carrier biofilm and granular sludge, biofilm supported nitrifying bacteria and denitrifying phosphorus granular sludge were used for investigating the effect of the hydraulic retention time (HRT) on nitrogen and phosphorus removal to arrive at optimizing process parameters. In the experiment, HRT was set at 6 h, 7 h, 8.5 h and 10.5 h. The results showed that when HRT was 8.5 h, the removal rates of COD, ammonia nitrogen and total nitrogen were 91.26%, 80.68% and 70.58% respectively. The release rate of phosphorus was 0.47 mg P·(g SS)-1·h-1, anaerobic phosphorus release and carbon source utilization were both at the highest rate, PO43--P removal rate 76.50%, denitrifying phosphorus removal efficiency 1.04 mg P·(mg NO3--N)-1. At the hydraulic retention time 8.5 h, the system had higher nitrogen and phosphorus removal efficiency. When the HRT was too short, nitrogen and phosphorus removal was incomplete, If too long, the system was unstable. Therefore, the system's optimal hydraulic retention time was 8.5 h.
    Effects of charge pressure on continuous production of CO2 hydrate in compression refrigeration cycle
    XIE Zhenxing, XIE Yingming, ZHOU Xingfa, FANG Yajun
    2014, 65(6):  2301-2307.  doi:10.3969/j.issn.0438-1157.2014.06.047
    Abstract ( 571 )   PDF (1837KB) ( 345 )  
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    A novel pilot-scale apparatus was designed to continuously produce CO2 hydrate for cool storage. The pre-chilling time, amount of CO2 hydrate formation, hydration ratio, and cool energy of hydrate were analyzed under different CO2 charge pressures. Results showed that CO2 hydrate formed during the rising process of CO2 bubbles in water and cumulated at the gas-liquid interface. The cool storage performance can be improved greatly as the charge pressure increases. Under charge pressure of 4.2 MPa, the pre-chilling time, amount of hydrate formation, hydration ratio and latent cool energy storage are 8 min, 8.44 kg, 75.1% and 4.22 MJ respectively. When the charge pressure is higher than 3.8 MPa, large temperature differences appear between the middle and low parts of reactor, resulted from low thermal conductivity of formed hydrate. Evaporation of liquid CO2 reduces reactor temperature to 0℃ or even lower at late stage of hydrate formation, which is more evident at higher charge pressures.
    FG-DVC model for oil shale pyrolysis
    WANG Qing, WANG Rui, JIA Chunxia, REN Liguo, WANG Haotian, YAN Yuhe
    2014, 65(6):  2308-2315.  doi:10.3969/j.issn.0438-1157.2014.06.048
    Abstract ( 821 )   PDF (622KB) ( 410 )  
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    To study the relationship between the structure of oil shale and its pyrolysis, a series of experiments for Gansu oil shale was performed at heating rates of 5, 20, 50℃·min-1 using a TG-FTIR (Thermogravimetric Analysis-Fourier Transform Infrared Spectroscopy) analyzer. The CH4, CO, CO2, H2O and tar produced by pyrolysis were quantitatively analyzed. The kinetic parameters were calculated with a nonlinear least-squares curve-fitting method. The FG-DVC (Functional Group-Depolymerization Vaporization Crosslinking) model, which was established based on the structure of fuel, was employed to quantitatively predict the product yields of pyrolysis. The results showed that devolatilization reaction taken mainly place at temperature rangeof 200-600℃. Aliphatic hydrocarbon was predominant organic functionalgroup in shale oil. The initial temperature for release of gaseous products had different order due to various activities of functional groups. The calculated activation energy (E) was basicly between 188-239 kJ·mol-1, and the pre-exponential factor (A) was between 109-1013 s-1. Good agreement was observed between the model prediction and TG-FTIR experimental results for the oil shale studied, indicating that the pyrolysis process of Gansu oil shale could be well described by the FG-DVC model.
    Characteristics of products from sewage sludge pyrolysis at various temperature ranges
    JIN Pen, LI Baoxia, JIN Cheng
    2014, 65(6):  2316-2322.  doi:10.3969/j.issn.0438-1157.2014.06.049
    Abstract ( 609 )   PDF (7845KB) ( 360 )  
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    Municipal sewage sludge (i.e. sludge) at various temperature ranges was analyzed by proximate analysis and thermogravimetric analysis methods. The gaseous components produced by the sludge pyrolysis were detected by gas chromatography (GC), while the morphology and specific surface area of pyrolytic char measured by SEM and BET techniques, respectively. The results show that the pyrolysis process of sludge can involve water evaporation, organics volatilization and char formation steps. There are obvious differences between the gas components obtained at different ranges of pyrolysis temperature. The H2 content will rapidly increase when pyrolysis temperature is larger than 350℃, the maximum CH4 content obtained when temperature is in 350-450℃, the temperature range generated CO is mainly in 350-750℃, and the CO2 content declines for the whole range of pyrolysis temperature. With rising final temperature of pyrolysis, the char structure becomes more and more loose and it specific surface area increases. The maximum specific surface area of char produces is 55 m2·g-1 at 750℃.
    A simple method for evaluating biodegradability of pre-ozonized water
    GAO Yan, CHEN Yao, NI Jinlei, TONG Shaoping, MA Chun'an
    2014, 65(6):  2323-2328.  doi:10.3969/j.issn.0438-1157.2014.06.050
    Abstract ( 1088 )   PDF (564KB) ( 565 )  
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    After studying changes of biodegradability (BOD5/CODCr, the ratio of biochemical oxygen demand after 5 days to chemical oxygen demand) of several refractory organic compounds before and after pre-ozonation a oxidative degree conception of organic compound, defined as (4TOC-CODCr)/4TOC, in which TOC refers to total organic carbon, has been put forward. The results show that after pre-ozonation the oxidative degrees and biodegradability of nitrobenzene, 1,2-dimethyl phthalate and sulfosalicylic acid solutions all increases, and that there is a positive correlation between the sample's oxidative degree and their biodegradability. The BOD5/CODCr values of the samples can be more than 0.2 when its oxidative degrees are greater than 0.65, showing that these samples can be directly treated by biological treatment. The results of pre-treating acidic chemical wastewater by an advanced ozone-based oxidative process (Ti(Ⅳ)/H2O2/O3) show that the removal rates of CODCr and TOC were 66.09% and 34.09% after 120 min, respectively, and that the oxidative degree and BOD5/CODCr value of the acidic chemical wastewater increased from initial 0.346 and 0.05 to 0.664 and 0.332, respectively. There also is a good positive correlation between the oxidative degree and the BOD5/CODCr value. The results mentioned above indicate that the oxidative degree value can probably be used to evaluate the biodegradability of wastewater. Due to the determination of the oxidative degree is simple and fast, it will be of significance for common application of ozonation technology in pre-treatment of refractory wastewater.
    Effect of external circulation on performance of IC reactor
    ZHANG Yi, LIU Min, CHEN Ying, GU Qing, TANG Wei
    2014, 65(6):  2329-2334.  doi:10.3969/j.issn.0438-1157.2014.06.051
    Abstract ( 860 )   PDF (1558KB) ( 278 )  
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    In order to improve the performance of internal circulation(IC) reactor in which granular sludge had formed, an additional external circulation device was added to the reactor. The operation stability of this system was investigated at various reflux ratios of 0, 1.0, 2.0, 3.0 and 4.0. Compared with without external circulation situation, additional device do not indeed damage anaerobic conditions inside the IC reactor and the reactor operation was stable at given range of reflux ratio. When chemical oxygen demand(COD) of influent was 6000 mg·L-1, hydraulic retention time(HRT) about 10h, and volume loading 14 kg·m-3·d-1, the MLSS of system (mixed liquid suspended solids) and the removal rate of COD increased with the growth of reflux ratio, and could reach the maximum 97.3% and the lowest COD of effluent 160 mg·L-1 respectively. With increase of reflux ratio, the total quantity of biogas produced increased to 171.2 L·d-1. The methane production increased at the beginning and then maintained stabilization, and was 91.7 L·d-1 at reflux ratio 2.0. Remarkably, biodiversity in granular sludge had been improved due to additional external circulation. After the system with additional external circulation operated for a period of time, the dominant bacteria for methane production changed from Methanobacterium to Methanococcus. After comprehensive consideration of energy consumption and COD removal rate, the optimal reflux ratio would be 2.0.
    Experimental research on treating reservoir water contaminated by algae using GAC-sand dual media filter flofilter
    WANG Yonglei, LI Jun, ZHANG Kefeng, JIA Ruibao, LI Mei, SONG Wuchang, LI Ying
    2014, 65(6):  2335-2343.  doi:10.3969/j.issn.0438-1157.2014.06.052
    Abstract ( 826 )   PDF (866KB) ( 308 )  
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    The algae pollution of reservoir water is serious increasingly, the traditional process of sedimentation solid-liquid separation hardly meets the requirement of clearwater. GAC-sand-double-filtration flofilter was built to treat the high algae reservoir water derived from yellow river, and the running and operating characteristics of this flofilter were investigated. The experiment results showed that, the effect of running was excellent when polyaluminum ferric chloride(PAFC) dosage was 4.0 mg·L-1 (Al3+), air pressure 0.4 MPa, and reflux ratio 8%. Biomass of GAC and sand filter layer mainly existed in the carbon layer, which accounted for 97.4% (the highest value was 50.2 nmol P·g-1), and its biomass was 16.7 times of sand layer (3.0 nmol P·g-1), so the removal of pollutants occured mainly in the carbon layer. During the test, removal efficiency of particulate matter, blue-green algae, turbidity, CODMn, NPOC, UV254, ammonia nitrogen reached 96.48%, 92.40%, 92.56%, 57.41%, 51.60%, 52.50%, 75.67% respectively. Odor reduced from 4 to 0. Contents of geosmin and methylisoborneol were both less than the detection limit. Removal efficiency of chloroform, chlorodibromomethane reached 60% and 55.1%. The results showed that, flofilter process had a great removal on conventional index,algae,odor substances and disinfection byproducts precursors.
    Effect of different nitrogen sources on producing dissolved ferric ions in biological oxidation process of ferrisulfas liquor
    XUE Lin, QIN Songyan, LIU Zongyu, WU Lili, XIAO Jufang, XIE Yonglei
    2014, 65(6):  2344-2349.  doi:10.3969/j.issn.0438-1157.2014.06.053
    Abstract ( 545 )   PDF (768KB) ( 229 )  
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    Acidithiobacillus ferroxidans was used to oxidize Fe2+ into Fe3+ in the ferrisulfas liquor, and then dissolved Fe3+ was reduced by H2S, achieving both reclamation of the liquor and removal of H2S. The key factor for the removal efficiency of this treatment system was high concentration of dissolved Fe3+. However, when NH4+ and K+ were excessive, most portions of dissolved Fe3+ would be transferred into Jarosite. The nitrogen source was optimized to obtain high concentration of Fe3+ by controlling its ingredients and concentrations. It showed that (NH4)2HPO4 could replace (NH4)2SO4 to be the nitrogen source and its concentration in 0.33-1 g·L-1 was a suitable range for cell growth of Acidithiobacillus ferroxidans. At 1 g·L-1, the bacterial growth did not exhibit obvious lag period; average oxidation rate of Fe2+ was 0.221-0.229 g·(L·h)-1, dissolved Fe3+ increased to 7.62-7.72 g·L-1, and precipitation was 1.17 g·L-1. Therefore, the optimal concentration of (NH4)2HPO4 was 1 g·L-1. In order to reduce cost, the concentration was lowered 0.33 g·L-1. This technique not only maintained the Fe2+ oxidative activity of Acidithiobacillus ferroxidans but also effectively increased dissolved Fe3+ produced during bacterial culture process, providing scientific optimization basis for removal of H2S by the ferrisulfas liquor.
    Preparation of polyacrylamide supermacropore cryogel beads and its bicompatibility and adsorption behavior
    LU Danping, ZHAN Xiaoyong, LIN Dongqiang, YAO Shanjing
    2014, 65(6):  2350-2356.  doi:10.3969/j.issn.0438-1157.2014.06.054
    Abstract ( 848 )   PDF (2697KB) ( 448 )  
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    Novel supermacropore cryogel beads were prepared by combining the inverse-suspension and cryo-polymerization methods under frozen condition. The mean diameter of the beads was 234.1 mm, and the pore size was 10-50 mm. The cation-exchange cryogel beads were prepared by in-situ grafting of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPSA) onto the pore surface of the cryogel beads. The biocompatibility of the cryogel beadswas measured. The adsorption of protein and Cu2+ on the cryogel beads was also discussed. The growth of E.coli was little affected when cryogel beads existed in the cultivation. The cryogel beads had stronger adsorption ability after grafting AMPSA, and the adsorption capacity of Cu2+ could reach 1.14 mmol·g-1. Meanwhile, the cryogel beads grafted with AMPSA had the ability of protein adsorption, and the adsorption capacity for lysozyme reached 54.5 mg·g-1. Such cryogel beads could be used in immobilization of microorganisms, separation of biomass components and adsorption of heavy metal ions.
    Modified polylactic acid loading docetaxel for anticancer drug delivery
    LI Ruiduan, ZHANG Jianjun, CHEN Jianfeng, TENG Wei, LI Caixia, WANG Jiexin
    2014, 65(6):  2357-2362.  doi:10.3969/j.issn.0438-1157.2014.06.055
    Abstract ( 729 )   PDF (1410KB) ( 417 )  
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    Nanoparticles based on poly(2-amino-1, 3-propanediol carbonic ester-co-lactide)-g-PEG(P(LA-co-CA)-mPEG) were prepared by using the emulsion solvent diffusion method. The copolymer of P (LA-co-CA) was prepared by using ring-opening polymerization with diethylzinc (ZnEt2) as initiator, and then benzyl oxygen group was taken off to obtain P (LA-co-CA). With the anticancer drug, docetaxel (DTX), as a model drug, the morphology of nanoparticles was characterized with scanning electron microscopy (SEM) and the size and size distribution were determined by dynamic light scattering (DLS). SEM images and DLS results revealed that the particles were spherical in shape and about 100 nm in size, which was suitable for intravenous injection and close to the typically required size under physiological conditions. Thus, nanoparticles of P (LA-co-CA)-mPEG could be used as biodegradable, biocompatible, and cell-specific targetable nano-structured carriers for intracellular delivery of hydrophobic anticancer drugs.
    Preparation of potassium sulfate from K-feldspar by hydrothermal alkaline method: reaction principle and process evaluation
    MA Hongwen, SU Shuangqing, YANG Jing, CAI Biya, LIU Meitang, YAO Wengui, PENG Hui
    2014, 65(6):  2363-2371.  doi:10.3969/j.issn.0438-1157.2014.06.056
    Abstract ( 1387 )   PDF (4920KB) ( 511 )  
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    To develop an efficient and clean technique for comprehensively utilizing potassic syenite resources exposed in the Eastern Qinling to Dabie area of China, a series of experiments were performed using a typical K-feldspar powder as raw material, with focus on the hydrothermal stability of microcline in KOH-H2O solution, reaction principle of preparing potassium sulfate, as well as processing by-products from alumina and silica residue. Microcline was easily transformed into kalsilite by dislodging 2/3 SiO2 of the K-feldspar in the solution, resulting in nearly hundred percent higher concentration of K2O in the solid product, from which nearly pure solution of potassium sulfate was then obtained by dissolution with sulfuric acid, and further potassium sulfate was crystallized by evaporation of the solution or by the alcohol precipitation method. The alkaline solution of mainly potassium silicate reacted with lime milk to precipitate calcium silicate hydrate, from which needle-shaped wollastonite powder was synthesized hydrothermally, and then by calcination. The alumina and silica residue were used to make calcined kaolin first by acidic washing, and then by calcination. The whole procedure developed in this research was simple and economical, with recovery ratio of K2O up to 94.0%. In such a way, the components of K2O, Al2O3, and SiO2 in K-feldspar of the ores were wholly transformed to valuable products, giving rise to maximum utilization of K-feldspar resources, and also minimum consumption of relevant mineral resources. The technique is noted for energy conservation, high efficiency and clean production.
    Synthesis, characterization of propargyl-cardanol and non-isothermal curing kinetics of its polymer
    WU Jing, SHI Tiejun, ZHANG Fang, WANG Qidong, ZHOU Xun
    2014, 65(6):  2372-2377.  doi:10.3969/j.issn.0438-1157.2014.06.057
    Abstract ( 665 )   PDF (622KB) ( 355 )  
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    Propargyl cardanol was synthesized using cardanol and propargyl bromide by phase transfer catalyst reaction. The chemical structure of propargyl cardanol was characterized by FT-IR, 1H NMR. The results indicated that propargyl cardanol as target compound was obtained through the Williamson ether reaction. Thermal stabilization of poly-propargyl cardanol was evaluated with TG. The initial weight-loss temperature of cured propargyl cardanol was 419℃ and char yield at 800℃ was 14%, which illustrated that the cured propargyl cardano owned well-deserved thermal stability. According to DSC curves, curing kinetic parameters were calculated by two thermo-analysis methods of Kissinger and Flynn-Wall-Ozawa. The respective apparent activation energies were 143.46 and 145.15 kJ·mol-1 respectively and the order of curing reaction both approached to 1, which illustrated that these two kinds of mode were suitable for this system.
    Preparation of amphiphilic acrylic block copolymer by DPE method and application as pigment dispersant
    REN Qiang, WANG Lili, LI Jian, DENG Jian, FANG Jianbo, WANG Chenyi, CHEN Jianhai
    2014, 65(6):  2378-2385.  doi:10.3969/j.issn.0438-1157.2014.06.058
    Abstract ( 613 )   PDF (677KB) ( 546 )  
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    Controlled free radical polymerization of butyl methacrylate (BMA) was performed by using DPE as molecular weight regulator and AIBN as initiator. The influence of solvent, dosage of DPE and reaction time on polymerization kinetics were studied. Poly (butyl methacrylate) (PBMA) with terminal DPE semiquinoid structure and polydispersity less than 1.43 was obtained. Amphiphilic block copolymer PBMA-b-PDMAEMA with polydispersity of 2.0 was prepared by using PBMA as macroinitiator. The composition of copolymer determined by hydrogen proton nuclear resonance (1H NMR) was similar to that calculated from gel permeation chromatography (GPC). Two glass transition temperatures of the prepared block copolymer at 11℃ and 35℃ could be detected by differential scanning calorimetry (DSC). Rheological investigation, laser particle size analysis of pigment paste and performance of coating film revealed that dispersing efficiency of phthalocyanine blue pigment in acrylic resin was enhanced greatly by using the prepared PBMA-b-PDMAEMA as dispersant.
    Fabrication of porous structure of poly(e-caprolactone) via microcellular injection molding combined with chemical foaming
    WANG Xiaofeng, JIANG Jing, HOU Jianhua, WANG Shiwei, LI Qian, TURNG Lih-Sheng, SHEN Changyu
    2014, 65(6):  2386-2392.  doi:10.3969/j.issn.0438-1157.2014.06.059
    Abstract ( 779 )   PDF (6462KB) ( 523 )  
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    The physical foaming technology of supercritical fluid foaming and chemical foaming technology were combined to fabricate porous structure for polymers. Sodium bicarbonate was used as a chemical foaming agent. Poly(ε-caprolactone) (PCL) was first blended with sodium bicarbonate by a twin screw extruder and pelletized. The different foaming processes were conducted on a conventional injection molding machine and a microcellular injection molding machine separately. The foaming results were investigated by comparing the two methods of injection molding and microcellular injection molding. The results revealed that it was feasible by combining physical foaming and chemical foaming to fabricate porous structure for PCL, whose foaming quality was better than that of only chemical foaming method. The introduction of chemical foaming agent not only improved general foaming, but also served as nucleating agent of the gas bubbles of physical foaming. The interconnectivity of the pores was investigated, as well as the "web" structure on the cell walls. When the bubbles were growing, the cell walls were stretched in different directions, and the mutual wall of neighbored pores was stretched by the pores, therefore the "web" structure was obtained.
    Synthesis and properties of novel TMPPs/non-ionic waterborne polyurethane
    YAN Minxiang, ZHU Yan'an, QU Jinqing
    2014, 65(6):  2393-2399.  doi:10.3969/j.issn.0438-1157.2014.06.060
    Abstract ( 1393 )   PDF (717KB) ( 893 )  
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    The novel hydrophilic monomers trimethylolpropane phthalate esters (TMPPs), trimethylolpropane monoesters of maleic acid (TMPMs) and trimethylolpropane succinic monoester(TMPSs) were synthesized by esterification of trimethylolpropane(TMP) with phthalic anhydride(PA), maleic anhydride(MA) and succinic anhydride(SA), respectively. Then the anionic/non-ionic aqueous polyurethane dispersions (PUD) were synthesized by the prepolymer process using the novel hydrophilic monomers and polyoxyethylene ether (YmerTM N120) as compounding hydrophilic component. The effects of the type of hydrophilic monomers and mass ratio of TMPPs/N120 on the chemical resistance, hardness, mechanical properties and thermal stability of PUD films were studied. The storage stability, film hardness, water-and alcohol-resistance of PUD prepared from TMPPs were better than those from TMPMs and TMPSs. With increasing TMPPs/N120 mass ratio, the tensile strength of PUD film increased, elongation at break decreased, PUD film hardness increased and alcohol-resistance became good, while PUD solids contents decreased. The optimal mass ratio of TMPPs and N120 ranged from 6:5 to 4:8. Compared with DMPA, TMPPs could improve the hardness and thermal stability of PUD films, and significantly strengthened stain resistance, including resistance to ink, coffee, tea and wine. Therefore, TMPPs is a good hydrophilic compound to prepare PUD.