Please wait a minute...
Table of Content
05 February 2009, Volume 60 Issue 2
    Research progress of CO2 capture by using ammonia from flue gas of power plant
    LIU Fang, WANG Shujuan, CHEN Changhe, XU Xuchang
    2009, 60(2):  269-278. 
    Abstract ( 703 )   PDF (1094KB) ( 1415 )  
    Related Articles | Metrics

    With the coming of the postKyoto period,CO2 removal by using ammonia solutions has become an emerging,hot research subject in the recent yearsThis paper focuses on the related researches on the mechanism of CO2 removal by the ammonia method,major technical details and parameters,and gives a detailed summary and analysisSome conclusions of the researches,existing problems and the future of this technology are describedThe results of the experiments and simulations show that the efficiency of CO2 removal by ammonia solutions could reach more than 90% and the CO2 absorption capacity might be above 1.0 kg CO2/kg NH3Experimental results show that CO2 removal efficiency,absorption capacity and absorption rate mainly depend on the concentration of aqueous ammonia,reaction temperature of absorption and conditions for reagent regenerationThe economic analysis tells that the combined removal of acid gases and heavy metal from flue gas by using ammonia might achieve the goal of only 20% increase in the cost of electricity(COE).

    Determination of optimal cleaning cycle for heat exchanger 
    subject to fouling based on the second law of thermodynamics
    WU Shuangying, SU Chang, LI Yourong
    2009, 60(2):  279-286. 
    Abstract ( 924 )   PDF (1280KB) ( 473 )  
    Related Articles | Metrics

    Based on the combination of the second law of thermodynamics and thermo-economic principle with the asymptotic fouling model, the costobjective function and the optimal cleaning cycle of heat exchanger were formulated by introducing exergy transfer and heat transfer effectiveness for a heat exchanger subject to foulingThe results showed that the optimal cleaning cycle and the corresponding total cleaning cost determined by the second law of thermodynamics might be greater or smaller than those by the first law of thermodynamics, because exergy price was different from heat price more or lessIn the meantime, the optimal cleaning cycle, representing minimum cost of operation and maintenance of heat exchangers varied with flow patterns of heat exchanger, number of heat transfer units without fouling, the ratio of cold to hot fluids heat capacity, the cleaning time and the other cost parametersIn addition, the effect of the ratio of cold to hot fluids heat capacity and a smaller number of heat transfer units without fouling on the optimal cleaning cycle was not obvious as compared with other parameters.

    Nonlinear acoustical properties of liquid and supercritical carbon dioxide
    LU Yigang, SUN Xiaoguang
    2009, 60(2):  287-293. 
    Abstract ( 765 )   PDF (1796KB) ( 857 )  
    Related Articles | Metrics

    Several acoustic parameters including the pressure coefficient of ultrasonic velocity,temperature coefficients of ultrasonic velocity and the nonlinear acoustic parameter of liquid and supercritical carbon dioxide at different temperatures and pressures were calculated by using data of sound velocity,density,specific heat at constant pressure and bulk coefficient of expansion of carbon dioxide provided by the National Institute of Standards and Technology,USAThe nonlinear acoustical characteristics of liquid and supercritical carbon dioxide were analyzed and summarizedThe nonlinear acoustical characteristics of supercritical carbon dioxide were contrasted with those of liquid carbon dioxide and common organic liquidThe nonlinear acoustical characteristics around the critical angle were analyzed in detailInvestigation indicated that the nonlinear acoustical characteristics of liquid carbon dioxide resembled common organic liquid at normal temperature and normal pressureThe values of pressure coefficient of ultrasonic velocity,temperature coefficients of ultrasonic velocity and the nonlinear acoustic parameter of supercritical carbon dioxide might be positive or negative and the values changed with temperature and pressure regularlyThe higher the pressure and the lower the temperature,the more the nonlinear acoustical characteristics of supercritical carbon dioxide agreed with those of liquid carbon dioxide or common organic liquid at normal temperature and normal pressureNear the critical region,the change of these three parameters with temperature and pressure had a jump between positive and negative maximum.

    Excess volumes of mixture for 1,3-propanediol+water/ethanol
    LIN Mingsui, LIN Jinqing
    2009, 60(2):  294-298. 
    Abstract ( 632 )   PDF (364KB) ( 399 )  
    Related Articles | Metrics

    The densities of pure components and the binary mixtures of (1,3-propanediol+water), (1,3-propanediol+ethanol) were measured at 328.15—348.15 K for the liquid region and under ambient pressure over the whole range of compositions.The excess molar volumes were calculated by using the measured experimental densities.The excess molar volumes were negative over the whole mole fraction range for the temperature range studied for the binary mixtures.Volumetric data indicated that the intermolecular interaction between different molecules was stronger than that between the same molecules and packing effect was resulted from different molecule sizes in the studied mixtures.

    Hot spots during production of CaSO4 under microwave radiation
    WU Xinhua, YANG Xiaoqing, HUANG Kama
    2009, 60(2):  299-303. 
    Abstract ( 855 )   PDF (2007KB) ( 626 )  
    Related Articles | Metrics

    During the chemical reactions under microwave radiation,hot spots can usually be observed.Sometimes,hot spots may burn the reactants down or result in an explosion.A numerical model was presented to study the hot spots during the precipitation of calcium sulphate associated with microwave heating.Maxwell’s equations coupled with hydrodynamic equations and heat conduction equation were solved by using the finite-element method(FEM).The calculated results were in agreement with the experiments.The results showed that the location of the hot spots was variable,which was related to the precipitant of calcium sulphate,and the hot spots often existed near the interfaces between the solution and air or the precipitant.

    eat and mass transfer of sweeping gas membrane distillation
    CHEN Huayan, LI Huan, Lv Xiaolong
    2009, 60(2):  304-309. 
    Abstract ( 862 )   PDF (865KB) ( 522 )  
    Related Articles | Metrics

    Mass transfer and heat transfer through hydrophobic microporous membrane in sweeping gas membrane distillation(SGMD) was studied.A model about heat and mass transfer was constructed and solved.The effects of sweeping gas velocity, module length, feed flux and feed temperature on membrane flux were tested.The calculated membrane flux was compared with measured membrane flux.The experimental results showed that the calculated flux was near to the measured one.With increasing gas velocity membrane flux increased.Decreasing module length led to increasing membrane flux.Feed flux had little effect on membrane flux and with the increase of feed temperature, membrane flux increased dramatically.

    Particle sizing for gas-solids flow with digital in-line holography
    WU Xuecheng, PU Xingguo, PU Shiliang, YUAN Zhenfu, CEN Kefa
    2009, 60(2):  310-316. 
    Abstract ( 983 )   PDF (2516KB) ( 605 )  
    Related Articles | Metrics

    Digital in-line holography has been found to be a powerful tool in 3D diagnostics of gas-solids flows.A study on particle sizing in gas-solids flows using a digital holographic system was presented.The recorded particle hologram was numerically reconstructed by using wavelet transform algorithm.A 2D interpolation method was used to measure particle image size based on the identification and 3D location of particles,and the real sizes of particles were obtained based on the point spread function theory of numerical reconstruction of particle in-line hologram.Gas-solids flows produced by an annular nozzle and in the upper dilute zone of a cold CFB riser were tested by using a digital in-line holographic measurement system.Glass beads with sizes of 20-100μm were used,and a volume of 10 mm×10 mm×100mm in the flow space was measured.It was found that the particles in the measurement volume were successfully reconstructed.The measurement results of particle size distribution agreed with those obtained by a Malvern sizer,which showed excellent capability of digital in-line holography in particle sizing.

    Simulation of transients in natural gas pipelines using hybrid TVD/LW schemes
    LONG Xueyuan, YANG Min, XIE Yunjie, LUO Yun
    2009, 60(2):  317-324. 
    Abstract ( 634 )   PDF (1469KB) ( 260 )  
    Related Articles | Metrics

    The mathematical model describing transients in natural gas pipelines constitutes a non-homogeneous system of non-linear hyperbolic conservation.The time splitting approach was adopted to solve this non-homogeneous hyperbolic model.At each time step,the non-homogeneous hyperbolic model was split into a homogeneous hyperbolic model and an ordinary differential equation operator.An explicit 5-point,second-order-accurate total variation diminishing(TVD)scheme together with the Lax-Wendroff scheme to treat the neighborhood nodes of boundary,was formulated to solve the homogeneous system of non-linear hyperbolic conservation.The method of characteristics(MOC)was used to treat the boundary conditions at the inlet and outlet of the pipeline.An extreme condition involving instantaneous closure of a downstream valve and a real long pipeline’s transients were used to test the effectiveness of the hybrid schemes.The simulation results showed that the hybrid TVD/LW schemes could simulate real situation of the physical variables in a transient process successfully.

    Measurement of phase holdups of heat method oil/water two-phase flowbased on multiwavelet neighboring coefficient method
    ZHANG Chunxiao, ZHANG Tao
    2009, 60(2):  325-331. 
    Abstract ( 617 )   PDF (1783KB) ( 254 )  
    Related Articles | Metrics

    The temperature signal of oil/water two-phase flow is disturbed by noises from external interference which results in difficulty in distinguishing performance of oil/water and a small measuring range for oil holdup.In order to solve the problem, a new signal processing method based on the multiwavelet neighboring coefficient method was used.Compared with traditional threshold de-noising based on multiwavelet and vector threshold de-noising, the neighboring coefficient method can deal with the correlativity among the transformation coefficients and ensure better de-noising effect.Processing of a large amount of experiment data of oil/water have revealed that measurement of oil holdup based on voltage amplitude transform of thermocouple gave a measuring range of 3%—70% oil holdup.The mathematical expression between voltage ampitude fluctuation and oil holdup was obtained, and the measurement error of oil holdup was 7.1%.

    Particle dispersion characteristics of dense gas-solids two-phase coaxial jets
    ZHOU Huahui, XU Jianliang, LI Weifeng, LIU Haifeng
    2009, 60(2):  332-337. 
    Abstract ( 897 )   PDF (1742KB) ( 274 )  
    Related Articles | Metrics

    The particle dispersion characteristics of the dense gas-solids two-phase coaxial jets were investigated with high-speed camera.The results showed that with increasing gas velocity,three particle dispersion modes were observed:shear dispersion,wave dispersion and oscillating dispersion,after the particle flow passed through the intact length.The normalized intact length decreased with increasing gas velocity.For the wave dispersion,the unstable wavelength increased linearly with axial distance at different gas velocities.For the oscillating dispersion,oscillating frequency decreased at first and then increased with increasing gas velocity,so the oscillating frequency had a minimum when the gas velocity was about 65 m·s-1.

    Oscillation characteristics of two planar opposed jets
    SUN Zhigang, LI Weifeng, LIU Haifeng, YU Zunhong
    2009, 60(2):  338-344. 
    Abstract ( 803 )   PDF (2512KB) ( 383 )  
    Related Articles | Metrics

    he oscillation characteristics of two planar opposed jets were studied by using high-speed camera, smoke wire visualization and hot-wire anemometry (HWA).The oscillation periods of two planar opposed jets at different nozzle separations and exit nozzle velocities were studied.The results showed two models of instabilities:streamwise quasi-periodic oscillation model and deflection oscillation model.The oscillation model was mainly streamwise quasi-periodic oscillation model at L<5H (where L was the nozzle separation and H was the nozzle slot height), and it was mainly deflection oscillation model at L>5H.The deflection oscillation model had a stable period which decreased with increasing normalized nozzle separation.

    Hydrogenation of nitrobenzene to p-aminophenol using acidic ionic liquid as catalyst
    CUI Yongmei, YUAN Da, WANG Yanji, ZHAO Xinqiang
    2009, 60(2):  345-350. 
    Abstract ( 632 )   PDF (456KB) ( 619 )  
    Related Articles | Metrics

    A bifunctional catalytic system, Pt/SiO2 and a novel Brφnsted acidic ionic liquid of quaternary ammonium type N,N,N-trimethyl-N-sulfobutyl hydrogen sulfate ([HSO3-b-N(CH3)3]HSO4) was studied for the synthesis of p-aminophenol through the hydrogenation of nitrobenzene.The effect of ionic liquid concentration, amount of Pt/SiO2 and reaction conditions on the p-aminophenol yield and selectivity was investigated, and was compared with the result obtained over H2SO4 and Pt/SiO2 catalytic system.Under the reaction conditions of 85℃,4 h and 0.4 MPa, nitrobenzene conversion was 96.6% and p-aminophenol selectivity was 81.4% over Pt/SiO2 and [HSO3-b-N(CH3)3]HSO4, superior to the results over Pt/SiO2 and H2SO4.The possible reasons were the enhancement of nitrobenzene solubility influenced by ionic liquid, and the restriction of deep hydrogenation for phenylhydroxylamine.Pt/SiO2 catalyst could be recovered by filtration in vacuum, and p-aminophenol could be obtained from the filtrate by extraction, vacuum distillation and crystallization in sequence.Moreover, the ionic liquid and Pt/SiO2 catalytic system could be used for three times without obvious decrease of p-aminophenol yield.

    In situ catalytic cracking of sawdust fast pyrolysis vapors
    LU Qiang, LI Wenzhi, ZHANG Dong, ZHU Xifeng
    2009, 60(2):  351-357. 
    Abstract ( 1131 )   PDF (1273KB) ( 478 )  
    Related Articles | Metrics

    Fast pyrolysis of sawdust was performed and the pyrolysis vapors were analyzed with on-line pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS).Two catalysts, zeolite HZSM-5 and mesoporous SBA-15, were tested to determine their actions on the pyrolysis vapors.The catalytic cracking of the pyrolysis vapors with HZSM-5 significantly decreased the yields of acetic acid, hydroxyacetaldehyde, furans and phenols, and meanwhile a lot of aromatic hydrocarbons were formed, mainly toluene and xylenes.The catalytic cracking of the pyrolysis vapors with SBA-15 decreased the yield of acetic acid, slightly decreased the yield of hydroxyacetaldehyde, and increased the yields of furans and phenols.The results indicated that the two catalysts exhibited different catalytic cracking actions on the pyrolysis vapors.HZSM-5 was highly active in deoxygenation of the pyrolysis vapors.SBA-15 possessed very little activity to catalyze the pyrolysis vapors to form hydrocarbons, but its mesoporous structure allowed cracking of large molecules to smaller sawdust compounds.

    Variation of reaction heat for secondary reaction of FCC gasoline
    LIU Yibin, WANG Honggang, YANG Chaohe, SHAN Honghong
    2009, 60(2):  358-364. 
    Abstract ( 971 )   PDF (481KB) ( 412 )  
    Related Articles | Metrics

    The reaction heats for upgrading and catalytic pyrolysis of FCC gasoline were calculated from the formation enthalpies of the reactants and products.The effects of temperature, residence time and catalyst to oil ratio on the reaction heat were investigated.The calculation showed that upgrading and catalytic pyrolysis of FCC gasoline were all endothermic processes.The reaction heat was 80—150 kJ·kg-1 for upgrading of FCC gasoline and 370—620 kJ·kg-1 for catalytic pyrolysis.The reaction heat was related to reaction conditions, i.e., conversion of gasoline and product distribution.With rising reaction temperature, increasing catalyst to oil ratio, and expanding residence time,the reaction heat increased under the experimental conditions.If the catalyst to oil ratio was large enough, the increase of reaction heat became slower with further increasing catalyst to oil ratio.

    Bimodal polyethylene produced by oscillating operation of hydrogen in single gas-phase polymerization reactor
    LI Wei, HUANG Xingbing, WANG Jingdai, YANG Yongrong
    2009, 60(2):  365-371. 
    Abstract ( 909 )   PDF (1935KB) ( 406 )  
    Related Articles | Metrics

    A novel technology was presented to produce bimodal polyethylene with home-made metallocene catalyst APE-1G(Cp*2ZrCl2·2LiCl·THF) in single gas-phase reactor through oscillating operation of hydrogen periodically.The effects of hydrogen concentration, oscillating time distribution and oscillating operation period on molecular weight distributions were studied.The results showed that catalyst activity and molecular weight of the obtained polymers decreased due to the addition of hydrogen.Bimodal polyethylene obtained through oscillating hydrogen concentration periodically had a polydispersity index (PDI) range from 11.2 to 34.2.It was viable to control molecular weight distributions of bimodal polyethylene through hydrogen oscillating operation, especially through changing the oscillating operation period.

    Catalytic depolymerization of polycarbonate in sub-critical ethanol
    FANG Yuyuan, JIN Hongmao, PAN Zhiyan, ZOU Xia, LIN Chunmian
    2009, 60(2):  372-377. 
    Abstract ( 827 )   PDF (1867KB) ( 415 )  
    Related Articles | Metrics

    Catalytic depolymerization of polycarbonate (PC) in sub-critical ethanol was performed in a batch reactor under pressures 1.1 MPa to 5.9 MPa and at temperatures 140℃ to 220℃ for 15 min to 60 min.FT-IR, GC-MS and GC were used to analyze the products, and the depolymerization ratio of PC and the yield of bisphenol A (BPA) were estimated.The results showed that the depolymerization ratio of PC increased with the increase of temperature and reaction time, while the yield of BPA decreased because of its decomposition at elevated temperatures and long reaction time.The optimal condition for the yield of BPA was 170℃ and 1.7 MPa, in which the depolymerization ratio of PC reached 84.2% in 15 min and the yield of BPA was 95.7% of the expected value.Kinetic analysis showed the catalytic depolymerization reaction in sub-critical ethanol was a first-order reaction and its activation energy was 40.15 kJ·mol-1.

    Effect of calcination temperature on catalytic performance of olivine for toluene cracking
    YUE Baohua, BU Xianni, WANG Xueguang, DING Weizhong
    2009, 60(2):  378-383. 
    Abstract ( 1171 )   PDF (953KB) ( 347 )  
    Related Articles | Metrics

    The effects of calcination temperature on the structure, phase, reduction properties and catalytic behavior of olivine in toluene cracking were investigated by BET analysis, XRD, H2-TPR and TEM.It was found that the crystal form and catalytic activity of olivine were markedly influenced by calcination temperature. The main phases of olivine calcined at a lower temperature were Mg2SiO4 and Fe2O3. Increasing the calcination temperature to over 1100℃, Fe2O3 phase disappeared gradually and (Fe, Mg)SiO3 phase was formed, causing a significant decrease in the number of active sites.The perfect catalytic activity was related to higher free iron oxide contents which can be realized by appropriate thermal treatment.In the experiment, the olivine calcined at 900℃ showed the best catalytic activity and high resistance to carbon deposition.

    Analysis of reaction kinetics and numerical simulation of GaN growth by MOCVD
    XU Qian, ZUO Ran, ZHANG Hong
    2009, 60(2):  384-388. 
    Abstract ( 710 )   PDF (506KB) ( 474 )  
    Related Articles | Metrics

    A chemical reaction model with main reactions and parasitic reactions of GaN growth was proposed.The growth process was described as some steps of main reactions with some steps of parasitic reactions, which evolved parallel with the main ones.The growth rate of GaN obtained through numerical simulation was compared with the one from experiment reported in literature, and was consistent with the result of literature.when their experimental outcomes obtained in a real MOCVD reactor were transformed to the same condition of the simulation model.It was shown that the GaN growth rate was influenced sharply by the concentration of TMGa, but there was no simply linear relationship between them.

    Influence of inorganic salts on pervaporation performance 
    of PDMS/ceramic composite membranes
    HOU Dan, WEI Wang, XIA Shanshan, XIANGLI Fenjuan, CHEN Yiwei, JIN Wanqin
    2009, 60(2):  389-393. 
    Abstract ( 747 )   PDF (506KB) ( 302 )  
    Related Articles | Metrics

    There are many significant advantages when pervaporation is used in the separation of ethanol/water system.The current studied systems are mainly the binary feed mixtures, but the real systems are commonly multi-component mixtures and might include inorganic salts and sugars, which may have effects on the pervaporation performance of the membrane.In this work the effects of three inorganic salts (NaCl, KCl and MgCl2) on the pervaporation performance of polydimethylsiloxane (PDMS)/ceramic composite membranes were studied.The results showed that the addition of inorganic salts caused simultaneously the increase of the flux and the separation factor.Among the three salts, MgCl2 had the most notable effect on the pervaporation performance.The separation factors of the tertiary system were 2.8, 2.5 and 2.4 times of those of the ethanol/water binary system for MgCl2, NaCl and KCl respectively.The experimental phenomena could be explained by the ethanol activity, which was calculated by using the Setschenow empirical equation.

    Kinetic model for microwave-assisted extraction
    GUO Pingsheng, LIU Haili, NING Junxian, TANG Xianjian
    2009, 60(2):  394-400. 
    Abstract ( 651 )   PDF (513KB) ( 228 )  
    Related Articles | Metrics

    The excitation energy acquired by the goal molecules in microwave field was theoretically analyzed from the interaction between goal molecules and microwave field.The effective diffusion equation of the goal molecules in bulk material in microwave field was deduced on the basis of the theory of liquid lattice model, and the mechanism of goal component diffusion enhanced by microwave field was analyzed.The results indicated that the bulk material porosity increased by microwave field and non-calorific energy acquired by goal molecules were the main reasons for the goal molecules diffusion enhanced by microwave field, and the general characteristics of the extraction process enhanced by microwave field were revealed.A kinetic model of goal component diffusion in microwave field was further established by simplifying the effective diffusion equation.The fitting of experimental data showed that theoretical curves of different parameters of the same kinetic equation were in agreement with different experiment results respectively,and all fitting correlation coefficients were above 0.96.The experimental data fitted under different conditions satisfied the same kinetic law and the kinetic model established was adaptive and appropriate to some degree.

    Naphtha cracking furnace fault diagnosis based on adaptive quantum ant colony algorithm
    WANG Ling, WANG Xiuting, YU Jinshou
    2009, 60(2):  401-408. 
    Abstract ( 837 )   PDF (1302KB) ( 273 )  
    Related Articles | Metrics

    Considering the lack of the fault data in the real production process, support vector machine (SVM), which fits the small sample problem was adopted to diagnose the faults of Stone & Webster Ultra-selective Cracking (USC) naphtha cracking furnace.To eliminate the disturbances from the high dimensional data as well as system noises, a novel adaptive quantum ant colony optimization (AQACO) algorithm was proposed to select the fault features based on the classical ACO with the introduction of quantum bit.The results of numerical simulation experiments showed that the proposed AQACO had better global optimization ability.The results of diagnosis of cracking furnace sensor faults demonstrated that AQACO could find the fault features quickly and exactly, which effectively improved the fault diagnosis performance of SVM in terms of correctness and robustness.

    Thermal and electrochemical performance of novel binary molten salt electrolyte based on LiTFSI/NaTf
    TU Xiaohua, CHU Youqun, ZHAO Fengming, MA Chun’an
    2009, 60(2):  409-414. 
    Abstract ( 1049 )   PDF (1146KB) ( 359 )  
    Related Articles | Metrics

    The thermal and electrochemical performance of a novel binary low temperature molten salt electrolyte based on LiTFSI/NaTf was studied with thermogravimetry/differential thermal analysis(TG/DTA),electrochemical impedance spectroscopy(EIS)and cyclic voltammetry.TG/DTA showed that the electrolyte had good thermal stability with no thermal decomposition below 300℃.The eutectic temperature of the LiTFSI/NaTf was 188℃ at the molar ratio of 1∶3.The molten salt electrolyte had good ionic conductivity .The ionic conductivity decreased with the increase of LiTFSI molar fraction.The electrochemical window of the molten salt electrolyte at the molar ratio of 1∶3 was calculated to be 4.7 V at 230℃.

    Detection method based on color characteristic for coating aging deterioration
    TAO Lei, SONG Shizhe, JIN Weixian
    2009, 60(2):  415-420. 
    Abstract ( 714 )   PDF (1073KB) ( 501 )  
    Related Articles | Metrics

    This paper examines an analysis method of corrosion surface damage of coating materials by using the digital image processing technology and related theory of colorimetry.The corrosion morphology image acquisition system was established, and was used to capture the corrosion morphology of coating specimens, which were exposed in the field exposure station.To describe the discoloration of corrosion surface damages, the HSV color model was used.The Euclidean distance between uncorroded image and corroded image was extracted as color characteristic parameter. A method for automated identification system of discoloration of corrosion damages was developed based on this analysis, and could be an important step in the direction in corrosion inspection.

    Preparation of(S)-(-)-β-hydroxy-benzenepropanoic acid ethyl ester by asymmetric reduction of β-carbonyl phenylpropionate with immobilized CGMCC No.2266
    OU Zhimin, YANG Gensheng, GUO Fangyuan
    2009, 60(2):  421-427. 
    Abstract ( 630 )   PDF (1668KB) ( 481 )  
    Related Articles | Metrics
    ((S)-(-)-β-hydroxy-benzenepropanoic acid ethyl ester was synthesized by asymmetric reduction of β-carbonyl phenylpropionate with immobilized CGMCC No.2266 in dibutyl phthalate.100 ml microbial liquor containing 430 mg(dry weight)biomass preheated at 50℃ for 30 min was immobilized.After re-culturing for 72 h,the immobilized cells of 2 mm diameter prepared by 2% sodium alginate was used to reduce 17.2 mmol·L-1 β-carbonyl phenylpropionate in 300 ml dibutyl phthalate.The yield and enantiomeric excess of(S)-(-)-β-hydroxy-benzenepropanoic acid ethyl ester reached 92.2% and 100% respectively.Immobilized CGMCC No.2266 can be reused in reaction for ten times.The yield decreased with increasing substrate concentration.Batch addition of substrate can reduce inhibition of high concentration substrate.
    Quantitative study on mechanism of Mn(Ⅱ) catalytic ozonation of oxalic acid
    ZANG Xingjie, ZHANG Hua, SHI Rui, TONG Shaoping, MA Chun’an
    2009, 60(2):  428-434. 
    Abstract ( 691 )   PDF (982KB) ( 325 )  
    Related Articles | Metrics

    Oxalic acid was degraded by Mn(Ⅱ) catalytic ozonation, and its mechanism was discussed by a quantitative analysis.The experimental results demonstrated that the ozonation efficiency increased with adding Mn(Ⅱ)catalyst to oxalic acid solution, and that Rctof the ozonation system also increased.The degradation of oxalic acid by Mn(Ⅱ) catalytic ozonation included three parts : direct ozonation, oxidation reaction of hydroxyl radical produced from the decomposition of the dissolved ozone, oxidation reaction of Mn(Ⅳ)and Mn(Ⅶ).The pH of solution not only influenced the degradation efficiency of Mn(Ⅱ)/O3, but also determined the contributing proportions of three different oxidation reactions.When the pH was 2.9, the apparent rate constant of degradation of oxalic acid by Mn(Ⅱ)/O3 was 28.280×10-4 s-1 ,and the contributing proportion of three-oxidation reactions was fO3∶fOH∶frest=2.1∶19.0∶78.9However, when the pH values were 5.3, 8.0 and 10.0, the apparent rate constants were 〖WTBZ〗1.597×10-4s-1, 1.535×10-4s-1 and 1.545×10-4s-1, respectively, and the contributing proportion of the three-oxidation reactions were fO3fOHfrest=24.9∶28.4∶46.7,fO3fOH∶frest=23.6∶54.5∶21.9 and fO3f OHfrest=19.6∶74.4∶6.0respectively.

    Excess enthalpy combustion characteristics in reciprocal porous media combustion system with heat recirculation
    WANG Guanqing, CHENG Leming, ZHENG Chenghang, LUO Zhongyang, CEN Kefa
    2009, 60(2):  435-443. 
    Abstract ( 883 )   PDF (1738KB) ( 467 )  
    Related Articles | Metrics

    Excess enthalpy combustion characteristics of low heating value gas were numerically investigated in a novel model of reciprocal porous media combustion system with heat recirculation.Based on the comparison of the model with the experimental results,the effective of the model was verified,and the mechanism of excess enthalpy combustion in the system was clarified.The influence of the conditional and material characteristic parameters on the excess enthalpy characteristics were analyzed including half period,heating value,secondary air ratio,heat capacity ratio,optical thickness,convective coefficient etc.The excess enthalpy combustion can be obtained in the system when the dimensionless heating value is no more than 3.48.The lower the heating value,the higher the level of the excess enthalpy is.The results also showed that the combustion efficiency was seldom influenced by those parameters and kept a high level at the steady combustion state,which further proved the high effectiveness of porous media combustion


    Adsorption of NO and NH3 over CuO/γ-Al2O3 catalyst by DRIFTS
    SUN Lushi, ZHAO Qingsen, XIANG Jun, SHI Jinming, WANG Lele, HU Song, SU Sheng
    2009, 60(2):  444-449. 
    Abstract ( 1394 )   PDF (1585KB) ( 573 )  
    Related Articles | Metrics

    Granular CuO/γ-Al2O3 catalysts were synthesized by the sol-gel method.The performance of CuO/γ-Al2O3 catalysts for selective catalytic reduction(SCR)was analyzed in a fixed bed adsorption system.The optimum temperature range for SCR reaction on CuO/γ-Al2O3 catalyst was 250—450℃.Based on the previous study,CuO/γ-Al2O3 catalysts were investigated with in-situ diffuse reflectance infrared fourier transform spectroscopy(DRIFTS)for revealing the reaction mechanism.The DRIFTS indicated both coordinated NH3 and NH+4 were present on the catalysts.NO and NO2 could be adsorbed on the catalyst surface and produce a number of different transformation species.Formation of NO-3 after O2 addition suggested the oxidation of adsorbed NO species to nitrates.When NO was introduced into the samples with pre-adsorbed NH3+O2,the coordinated NH3 on the catalyst surface was consumed rapidly.But NH+4 was not consumed under the SCR reaction.It indicated that these coordinated NH3 species could react with NO effectively.When NH3 was introduced into the samples with pre-adsorbed NO+O2,the intensity of adsorbed NO species did not change; it inferred that SCR reaction would not proceed.It was found that the SCR reaction could take place between the adsorbed NH3 and gaseous NO.The adsorbed NO and formed NO-2 and NO-3 species did not participate in the SCR reaction.

    Hydroxyl ammonium ionic liquids: synthesis and flue gas desulfurization
    ZHAI Linzhi, ZHONG Qin, DU Hongcai, HE Chuan, WANG Juan
    2009, 60(2):  450-454. 
    Abstract ( 801 )   PDF (1088KB) ( 769 )  
    Related Articles | Metrics

    A novel water-bath microwave method used for synthesis of hydroxyl ammonium ionic liquids was reported.A series of hydroxyl ammonium ionic liquids (ILs) consisting of ethanolamine, diethanolamine, triethanolamine or dimethylethanolamine as cations, and formic acid, acetic acid or lactic acid as anions were synthesized.Taking ethanolamine lactate ionic liquid as an example, the result of orthogonal experiment (L9(34)) showed the optimal synthesis conditions were 65 ℃, wave power of 300 W for 30 min with the molar ratio of 1︰1.1 (ethanolamine vs lactic acid).Under these conditions, the yield of the other eight ILs except dimethylethanolamine salts reached above 90%.Because of its higher capacity for absorption of SO2, ethanolamine lactate was selected as the better absorbent with the capacity of SO2 in ethanolamine lactate 1.063 (SO2 vs ethanolamine lactate).The results showed that the appropriate absorption temperature for SO2 was 25 ℃, desorption temperature was 90 ℃, and desorption time was 60 min.It was also found that water-bath microwave was able to accelerate the desorption of SO2.

    A novel titanium-supported silver electrode for electrochemical oxidation of borohydride
    YI Qingfeng, LI Lei
    2009, 60(2):  455-459. 
    Abstract ( 637 )   PDF (1126KB) ( 277 )  
    Related Articles | Metrics

    A novel titanium-supported silver catalyst(Ag/Ti)with a 3D network structure was prepared by the hydrothermal process using polyethylene glycol as a reduction agent.Electrocatalytic activity of the Ag/Ti electrode towards borohydride oxidation was evaluated by cyclic voltammograms(CVs).A direct oxidation process of borohydride on the Ag/Ti electrode was observed.The results showed that the Ag/Ti electrode presented a high anodic current density for borohydride oxidation,and the onset potential for borohydride oxidation was ca -0.64 V vs SCE at BH-4 concentration of 0.1 mol·L-1.This indicated that the Ag/Ti electrode exhibited high electrocatalytic activity for borohydride oxidation and it would be a promising anode used in direct borohydride fuel cells.

    Removal of cadmium ions from low concentration wastewater containing cadmium by modified starch
    ZHANG Yanlin, ZHANG Qiuyun, WANG Ting
    2009, 60(2):  460-464. 
    Abstract ( 714 )   PDF (981KB) ( 301 )  
    Related Articles | Metrics

    Graft copolymerization of acrylamide onto starch and reaction with mercaptoacetic acid subsequently were studied.The reaction product (St-AM-MCAA) was used in the treatment of wastewater containing low concentration cadmium ion (0.40 mg·L-1) as additive.An investigation was carried out to study the effect of St/AM (mass ratio of starch to acrylamide) on the grafting ratio and grafting efficiency and the content of thiol (SH) group.It was found that the cadmium ion removal percentage by St-AM-MCAA3 reached 89.7% and the residual concentration of cadmium ion in treated water was under 0.10 mg·L-1 in the conditions of pH=8 and additive concentration of 2.0 g·L-1 by selecting a high grafting ratio and thiol content product St-AM-MCAA3 as additive. The ability of St-AM-MCAA3 to remove low concentration wastewater containing cadmium ion was higher than that of St-AM3 by 10%.

    Saccharification hydrolysis of corn cob and bio-hydrogen production by anaerobic fermentation
    ZHANG Maolin, LI Lingchuan, SHEN Xiaowu, FAN Yaoting, HOU Hongwei, REN Baozeng
    2009, 60(2):  465-470. 
    Abstract ( 914 )   PDF (869KB) ( 398 )  
    Related Articles | Metrics

    The effects of acid hydrolysis pretreatment of corn cob on saccharification efficiency and fermentation bio-hydrogen production were investigated by orthogonal test design.The hydrolysis pretreatment of corn cob with dilute sulfuric acid was essential for adequately converting substrate into soluble saccharides and bio-hydrogen.The experimental results showed that acid hydrolysis pretreatment of corn cob was found most effective at hydrolysis temperature of 115℃, sulfuric acid concentration of 1.0%, hydrolysis time of 1.5 h and solid-liquid mass ratio 1∶10, in which both maximum saccharification efficiency of 0.5433 g·(g TVS)-1 and bio-hydrogen yield of 85.8 ml H2·(g TVS)-1 were observed.In addition, the mechanisms of degrading corn cob by acid hydrolysis and hydrogen fermentation were also discussed by means of X-ray diffraction(XRD)analysis and crystallinity calculation.

    Electrochemical oxidation behavior of 1,4-dichlorobenzene on Pt electrodes in mixed solvent
    LIU Qi, WANG Jiade, LIU Chenliang, CHEN Jianmeng
    2009, 60(2):  471-475. 
    Abstract ( 784 )   PDF (1202KB) ( 329 )  
    Related Articles | Metrics

    The mechanism and characteristics of electrochemical oxidation of 1,4-dichlorobenzen in simulated wastewater were investigated on a platinum electrode.The cyclic voltammetric profiles showed that the oxidation peak potential and current density increased with the increase of the concentration of 1,4-dichlorobenzene, nevertheless, the oxidation potential of 1,4-dichlorobenzene in acetonitrile-aqueous solution was smaller than that in acetonitrile solution.Chronoamperometric experimental results suggested that the 1,4-dichlorobenzene degradation included both direct electro-oxidation of 1,4-dichlorobenzene by loss of electrons and indirect oxidation with anodically formed free radicals.Additionally, parachlorophenol, 1,4-benzoquinone, maleic acid, oxalic acid, acetic acid,and formic acid were identified as main electro-oxidation products by ion chromatography or high performance liquid chromatography.Moreover, a yellow polymer film, which influenced the electrochemical oxidation process, was clearly identified as a rough surface after electrochemical reaction in comparison to a smooth and glossy surface of platinum electrodes without polymer film as observed from SEM image.

    Adsorption and encapsulation phenomena in thermoplastic composite
    ZHANG Chao, SHI Yonghui, DAI Gance
    2009, 60(2):  476-482. 
    Abstract ( 722 )   PDF (1786KB) ( 792 )  
    Related Articles | Metrics

    The preferential adsorption and encapsulation phenomena in ternary composites were investigated by studying the mechanical properties of the PP/GF/PA66, PP/GF/PET, PP/GB/PA66, PP/GB/PET and PP/PA66/PET composites.It was found that the polymer polarity played an important role in the interface formation during the processing.The polar inorganic fillers or polar polymer could be preferentially encapsulated by the polar polymer in the dipolar polymer matrix during the melted processing.Due to the preferential adsorption and encapsulation, the interface adhesion was improved and the mechanical properties of the ternary composites were also influenced by encapsulation.And better properties could be obtained after encapsulation.Furthermore, the relationship between encapsulation and interface tension was discussed.

    Particle stability of γ-methacryloxy propyl trimethoxysilane and styrene mini-emulsion copolymerization
    CAO Zhihai, SHAN Guorong
    2009, 60(2):  483-489. 
    Abstract ( 621 )   PDF (1112KB) ( 364 )  
    Related Articles | Metrics

    The evolution of particle size and the ratio of particle number (Np) and droplet number (Nd) of the mini-emulsion copolymerization of γ-methacryloxy propyl trimethoxysilane (MPS) and styrene (St) were investigated.The droplet and particle size were measured by dynamic light scattering (DLS).The individual conversion of St was followed by gas chromatography, and the overall conversion was measured by gravimetry.The surface tension of the mini-emulsion was measured with the plate method using Krüss processor tensiometer.With the increase of the ratio of MPS to St, the size of mini-droplets decreased gradually due to the decrease of the interfacial tension between oil and aqueous phase.The evolution of particle size and Np/Nd were tightly dependent on the nature of initiators.The particle size of the system initiated by KPS increased and Np/Nd decreased in the process of polymerization which could be ascribed to the increase of the formation of hydrogen bonding between particles due to the existence of the extending polymer chain with silanol groups on the interface of the latexBecause the radicals were mainly produced in the latex, the particle size of the system initiated by AIBN nearly kept constant in the process of polymerization.With the increase of the MPS/St [JP+3]ratio, the particle size increased, but Np/Nd decreased, which could be attributed to the decrease of adsorption ability of the surfactant on the latex and the increase of the formation of hydrogen bonding between particles as a result of the increase of hydrolysis resultants.The value of Np/Nd was independent of the amount of surfactant and HD.The sizes of initial mini-emulsion in acidic and basic conditions were much lower than that in neutral condition.However, as the polymerization proceeded, the particle size under acidic and basic conditions increased and the particle number decreased rapidly.It was worthwhile to note that the final products in acidic and basic conditions were still emulsion.

    In situ miniemulsion polymerization of water-borne polyurethanes(Ⅰ)Competition of polyaddition with hydrolysis of isocyanate
    ZHAN Xiaoli, SHI Ying, ZHANG Qinghua, CHEN Fengqiu
    2009, 60(2):  490-495. 
    Abstract ( 638 )   PDF (999KB) ( 667 )  
    Related Articles | Metrics

    The polyaddition of isophorone diisocyanate (IPDI) with hydrophobic diol was performed in miniemulsion to obtain water-borne polyurethane.The polymer structure was characterized with FTIR to determine the concentration ratio of urethane to urea group.The effects of hydrophobic diol, vinyl monomers, and such experiment parameters, as temperature, catalyst and surfactant on the competition of the main reaction (polyaddition of isocyanate- hydroxyl) with the side reaction (hydrolysis of isocyanate) were studied.Based on the experimental results, the physical model of the competition was established.It was found that the high reactivity of diol and the high hydrophilicity of vinyl monomer could favor the polyaddition.It was also shown that the hydrolysis could be restrained by decreasing surfactant concentration and decreasing temperature and the amount of catalyst.However, the hydrolysis could be restrained by increasing the surfactant concentration when polydimethyl siloxane (PDMS) took part in polymerization.

    Synthesis and characterization of anionic/non-ionic type high solid content polyurethane dispersion based on sulfonate and monofunctional polyethylene oxide polyether
    SUN Dongcheng, HUANG Zhongyuan
    2009, 60(2):  496-501. 
    Abstract ( 858 )   PDF (1819KB) ( 601 )  
    Related Articles | Metrics

    Polyurethane dispersions (PUDs) with solid content above 50% were synthesized by using polyether diol containing sulfonate (SPPG), monofunctional polyethylene oxide polyether initiated by methanol(PEOM), polycarbonate diol (PCDL), polyoxytetramethylene glycol(PTMG),isophorone diisocyanate (IPDI) and ethylene diamine (EDA) by the prepolymer method.The results showed that the Zeta potentials of PUDs were between -45 mV and -65 mV. The average particle sizes of PUDs were mainly in the range of 80—140 nm and the particle size distributions of PUD were mostly in the range of 60—200 nm.The average particle sizes decreased and the particle size distributions narrowed when the sulfonate group content increased and the molar ratio of NCO/OH and the PCDL content decreased.TEM analysis showed that the spherical shapes of the particle varied in a specific range.With the increase of shear rate, the viscosity of PUDs reduced, showing pseudo-plastic characteristics.

    Styrene mini-emulsion polymerization co-stabilized by predissolved fluoropolymer
    ZHANG Zhenqian, WU Haiyin, BAO Yongzhong, WENG Zhixue
    2009, 60(2):  502-506. 
    Abstract ( 586 )   PDF (2409KB) ( 374 )  
    Related Articles | Metrics

    The random copolymer (PSF) of styrene and dodecafluoroheptyl methacrylate (G04) was used as the sole co-stabilizer in styrene mini-emulsion polymerization.The effects of different masses of PSF, different fluorine contents of PSF on the conversion, the rate of the polymerization (Rp) and the diameter of droplets and the number of particles were investigated.The results showed that when fluorine content increased from 0 to 34.9%, the conversion of the polymerization increased from 67.5% to 80.1%, and Rp increased from 0.75×10-2 mol·L-1·min-1 to 1.74×10-2 mol·L-1·min-1.The fluorine content of PSF had little effect on the diameter of droplets, but it had an obvious effect on the number of particles in the polymerization.When the fluorine content of PSF increased from 0 to 34.9%, the number of particles per liter in the mini-emulsion system increased from 1.83×1016 to 2.07×1016.The mechanism of PSF as the sole co-stabilizer in styrene mini-emulsion polymerization was analyzed.

    Properties of SiO2 coated nano SiO2/CaCO3 sorbents by precipitation method
    SHI Qi, WU Sufang
    2009, 60(2):  507-513. 
    Abstract ( 682 )   PDF (3210KB) ( 293 )  
    Related Articles | Metrics

    SiO2 coated nano CaCO3 sorbents were prepared by using CO2 as precipitant and Na2SiO3 as silica source.TEM results showed that nano CaCO3 was coated by SiO2, and SEM & EDX tested Si content was 0.67%-4.93%.TGA was used to investigate the decomposition temperature and sorption properties under the condition of 600℃, 20% CO2 of absorbents.Compared with uncoated nano CaCO3, the decomposition temperature of SiO2 coated nano CaCO3 decreased by 9—42℃.With decreasing Si content, the cycle sorption ratio, cycle sorption capacity and sorption rate of SiO2 coated nano CaCO3 absorbents increased first but then decreased.The sample containing 1.05% Si had outstanding sorption properties.The 1st and 5th cycles sorption capacities were 8.9 mol·kg-1 and 6.0 mol·kg-1, 11% and 50% higher than uncoated nano CaCO3.The 5th cycle sorption rate of rapid reaction section was improved by 10% compared with uncoated nano CaCO3.SiO2 coated nano CaCO3 possessed higher sorption capacity and cycle sorption ratio, and better cycle stability than uncoated nano CaCO3.

    Preparation of brominated maleic rosin epoxy resin and its fire-retardant property
    HUANG Huoyang, HA Chengyong, LI Yinwen, SHEN Minmin
    2009, 60(2):  514-518. 
    Abstract ( 528 )   PDF (1035KB) ( 281 )  
    Related Articles | Metrics
    Brominated maleic rosin was produced from maleic rosin and bromine, and then brominated maleic rosin epoxy resin was synthesized by ring-open and ring-closing reaction of brominated maleic rosin and epichlorohydrin. The influence of reaction conditions was discussed, such as ring-open reaction temperature, mole ratio of material, concentration of NaOH and so on. The product which was prepared under suitable conditions had following property: epoxy value 0.30 mol/(100g) -1.The product was characterized by FT-IR and 1H-NMR. Brominated maleic rosin epoxy resin was cured by DDM. The test has proved that the curing product of brominated maleic rosin epoxy resin has better flame retardation.
    Synthesis of CdS/ZnS core-shell quantum dots in reverse micelle system and its optical property research
    LI Jiangsu, CHANG Shuquan, KANG Bin, DAI Yaodong
    2009, 60(2):  519-523. 
    Abstract ( 596 )   PDF (1489KB) ( 264 )  
    Related Articles | Metrics

    CdS and CdS/ZnS quantum dots were synthesized by the microemulsion method in sulfosuccinic acid bis(2-ethylhexyl)ester sodium salt(AOT) surfactant reverse micelles containing water.The products were characterized by UV-Vis spectrometer, transmission electronmicroscopy (TEM), energy dispersive X-ray spectroscope (EDX)and photoluminescence(PL) spectroscope.The diameter of CdS/ZnS nanoparticle was obvious larger than that of CdS nanoparticle.The diameter of the nanoparticle was estimated, which was confirmed by the images of TEM.The existence of core-shell structure was established by the result of energy dispersive X-ray analysis. PL studies of the samples showed that the luminescence from CdS was enhanced by the ZnS shell.A possible reason was that the ZnS shell reduced the number of defects on the surface of CdS quantum dots, which were assumed to act as centers for radiation-free recombination.

    Effect of diluent on pore size and connectivity of iPP hollow fiber microporous membranes via thermally induced phase separation
    YANG Zhensheng, ZHANG Guanghou, WANG Zhiying, LI Pingli, LI Chunli
    2009, 60(2):  524-530. 
    Abstract ( 1027 )   PDF (1726KB) ( 692 )  
    Related Articles | Metrics

    Isotactic polypropylene(iPP) hollow fiber microporous membranes were prepared via thermally induced phase separation(TIPS)method.The mixture of di-n-butyl phthalate(DBP)and dioctyl phthalate(DOP)was used as diluent.The effects of α(DBP mass fraction in mixed diluent)and β(iPP mass fraction in polymer solution)on pore size distribution of the membrane were investigated by N2-liquid displacement measurement.The connectivity of the membrane was evaluated with membrane tortuosity.It is noted that resulting membrane is apt to possess a narrow pore size distribution.For same β,the mean pore size and connectivity of resulting membrane decrease with increasing α.For α=0.20,with increasing β,mean pore size of resulting membrane increases with subsequent decreasing,while resulting membrane connectivity increases slightly.For α=0.35 or α=0.50,the mean pore size and connectivity of resulting membrane decrease with increasing β.It is indicated that the change of connectivity is attributed to the difference of the membrane topology.It is shown that membrane pore size and connectivity can be controlled effectively by choosing proper α and β.