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Table of Content
05 January 2012, Volume 63 Issue 1
    Discussion on development of coal chemical industry using low-carbon concept
    JIN Yong, ZHOU Yucheng, HU Shanying
    2012, 63(1):  3-8.  doi:10.3969/j.issn.0438-1157.2012.01.001
    Abstract ( 2050 )   PDF (458KB) ( 699 )  
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    Coal is an important fossil fuel with highest carbon content.Huge amount of CO2 emission caused by the use of coal has attracted high attention.In this paper,a new concept which is directed by low-carbon economy was proposed for the development of coal chemical industry in China.According to the actual situation in China,it is necessary and inevitable to choose the processes that can be highly effective multi-product as well as can combine coal chemical industry with petrochemical or metallurgical industry for utilizing effectively coal at different level.Besides,in order to lessen the dependence of oil imports and reduce the carbon emission intensity per unit GDP,we should take efforts to produce high value-added products from coal chemical industry instead of petrochemical industry,such as alkenes,aromatics especially benzene,toluene and xylene,methane and acetylene.Therefore,it is important to launch deeper research on crucial processes and new techniques like molecular tailoring and directional conversion.
    Ash fusion and viscosity-temperature characteristics of Yulin coal
    LI Dexia, ZHOU Zhijie, GUO Qinghua, YU Guangsuo
    2012, 63(1):  9-17.  doi:10.3969/j.issn.0438-1157.2012.01.002
    Abstract ( 1689 )   PDF (1352KB) ( 650 )  
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    There exists blocking in real gasification process of Yulin coal in whose ash the content of calcium and sulfur is high.The large fluctuation of viscosity-temperature curve measured in laboratory can be observed.FactSage 6.2 software was used to calculate ternary phase equilibrium and phase change rules during ash melting of Yulin coal under different ranges of high temperature.Based on these results and XRD measurement, the characteristics of ash fusion and viscosity-temperature changes caused by the addition of SiO2 as well as the reason of viscosity fluctuation were analyzed.The results show that the fusion temperature of Yulin coal ash decreased initially then increased with the increasing values of SiO2/Al2O3(S/A) and acid/base(A/B).There is a strong correlation between the formation of gehlenite and viscosity fluctuation within certain temperature ranges.The viscosity fluctuation of Yulin coal ash can be alleviated by adding appropriate SiO2(to the point when S/A=2.48), its amount can be obtained from binary phase diagrams calculated by FactSage.The numerical calculation results are in agreement with the experimental data, which proves that the chemical thermodynamic equilibrium analysis method is suitable for investigating the characteristics of ash melting.
    Viscous behavior and surface properties of binary mixture of ethyl acetate and isopropanol
    LING Jinlong,XU Minhong,YU Lili
    2012, 63(1):  18-24.  doi:10.3969/j.issn.0438-1157.2012.01.003
    Abstract ( 2607 )   PDF (503KB) ( 437 )  
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    The viscosity(η) and surface tension(σ) of ethyl acetate(EA) + isopropanol(IPA) binary mixture were measured over the entire composition range at 298.15—323.15 K and atmospheric pressure using Ubbelohde viscometer and pendant drop method,respectively.Viscosity deviations(Δη),excess Gibbs energy of activation of viscous flow(ΔG*E) and surface tension deviations(Δσ) were calculated from the experimental data.The excess thermodynamic properties,ΔηG*E and Δσ were correlated by the Redlich-Kister equation,and fitted parameters and standard deviations were obtained.The results show that ΔηG*E and Δσ are negative over the whole mole fraction range in the temperature range studied,and all deviations become larger as temperature decreases.The surface tension values were further used to calculate the surface entropies(Ss) and surface enthalpies(Hs) per unit surface area.The lyophobicity(β) and the surface mole fraction(xs2) of IPA were also derived using the extended Langmuir model.The obtained xs2 values indicate that the surface concentration of IPA is always higher than its bulk concentration and consequently confirm that the surface is enriched with IPA.
    Numerical simulation of gas diffusion in an incompressible thermal fluid with lattice Boltzmann method
    YONG Yumei1,YANG Chao1,YIN Xiaolong2,LIN Jun3
    2012, 63(1):  25-35.  doi:10.3969/j.issn.0438-1157.2012.01.004
    Abstract ( 2055 )   PDF (2473KB) ( 664 )  
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    It is of great significance to study the mass transfer and mixing of gas in natural convection flow caused by density gradient resulted from thermal conditions because chemical reactions mainly depend on the gas molecular concentration in fluids and the natural convection can strengthen the transport of gas molecules.The diffusion process of oxygen molecules is simulated with the natural convection developed in a simplified container,coupling with the effects of thermal and mass diffusion.On the basis of impressible flow of lattice Boltzmann(LB) model D2G9,a two-dimensional nine-speed lattice Boltzmann model D2Q9 of diffusion-natural convection is first built up to simulate the diffusion processes of heat energy and mass,with non-equilibrium extrapolation boundary scheme.Then the thermal natural convection and gas mass transfer process are simulated with three kinds of thermal boundary conditions in order to analyze and explore how the thermal conditions influence the fluid flow and mass transfer of gas.The calculated results are consistent with the published data.The effect of thermal condition on the natural convection flow is analyzed and the differences in velocity distribution between the numerical data and published data are discussed.The thermal flow dependent mass transfer provides a basis for designing appropriate thermal conditions to control the chemical reaction processes.
    Measurement of critical suspension speed in stirred tank using acoustic emission technique based on Hilbert-Huang transform
    HU Yuchen,HUANG Zhengliang,WANG Jingdai,YANG Yongrong
    2012, 63(1):  36-41.  doi:10.3969/j.issn.0438-1157.2012.01.005
    Abstract ( 1623 )   PDF (756KB) ( 565 )  
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    Acoustic emission(AE) technique,based on Hilbert-Huang transform(HHT) analysis,was used to analyze the AE signal received from the wall of a multi-layer slurry stirred tank,in which cation exchange resin was dispersed in water by agitation.IMF 1—5,which considered the characteristic scale(20—230 kHz),was obtained by empirical mode decompositon(EMD),representing the slurry system. A reconstructed AE signal was acquired by IMF 1—5.The energy of the reconstructed signal was found changing regularly with increasing impeller speed in the stirred tank.Then,a criterion to determine the critical suspension speed was presented.When energy began to remain constant after rapidly increasing,the corresponding impeller speed was the critical suspension speed.It was shown that the average absolute relative deviation(AARD) was about 3.83% compared with visual observation. Furthermore,external loop could diminish the critical suspension speed by intensifying axial flow in the tank,which meant that solid suspension was promoted.A predictive equation for calculating the critical suspension speed in a stirred tank with an external loop was proposed,which gave an AARD of 5.78%.Therefore,multi-scale analysis of acoustic signals based on HHT analysis was feasible for determining the critical dispersion speed and had the merit of being sensitive,non-intrusive and accurate.
    CFD simulations of liquid side local mass transfer characteristics and enhancement in capillaries under Taylor flow
    XU Min,HUANG Hai,LIU Hui,LEI Zhigang
    2012, 63(1):  42-50.  doi:10.3969/j.issn.0438-1157.2012.01.006
    Abstract ( 2251 )   PDF (2288KB) ( 429 )  
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    The characteristics of liquid side mass transfer under Taylor flow in capillaries were studied by performing computational fluid dynamics(CFD) simulations.The local mass transfer coefficients on bubble surface were evaluated,and the effects of bubble rise velocity,length of liquid film and slug length on the mean mass transfer coefficients of liquid film and the two caps were investigated.Three peak values of local mass transfer coefficient were found on bubble surface.The average mass transfer coefficient of liquid film increases with the increase of bubble rise velocity and decrease of liquid film length,whereas the average mass transfer coefficient of the two caps varies less.Mass transfer coefficient in liquid film decreases as the film contact time increases,while that in the caps changes less.Moreover,the principle of field synergy was used to explain the characteristics and enhancement of local mass transfer.The coordination between the velocity and concentration fields was better near the liquid film and two bubble caps.The results show that short film contact time for the same contact area could enhance the gas-liquid mass transfer under Taylor flow.Finally,empirical correlations were proposed to predict the liquid side volumetric mass transfer coefficients for short and long film contact time separately,and the predicted values in capillaries with diameters of 0.25—3 mm have a relative error within ±20%.
    Wall slip behavior and rheological characteristics of coke/water slurry
    MA Xiuyuan, DUAN Yufeng, LIU Meng, LI Huafeng
    2012, 63(1):  51-58.  doi:10.3969/j.issn.0438-1157.2012.01.007
    Abstract ( 1681 )   PDF (3453KB) ( 516 )  
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    Experimental researches were carried out on a slurry transportation system to investigate rheological properties and effects of wall slip behavior on flow properties of coke/water slurry flowing in pipes with different diameters.A numerical technique based on Tikhonov regularization was used to determine rheological properties and slip velocity.The results suggested that when coke concentration was 59.8%,coke/water slurry changed from pseudo plastic fluid to dilatant fluid with the increase of shear rate.Then the slurry became dilatant fluid completely with increasing concentration.While coke concentration came up to 63.4%,coke/water slurry changed from dilatant fluid back to pseudo plastic fluid.Rate of slip velocity change with shear stress depended on rheological properties of coke/water slurry.When coke/water slurry was dilatant fluid,the rate of slip velocity change increased sharply with shear stress.But there was no pronounced change with the rate of slip velocity change of pseudo plastic fluid.The change of slippage contribution lagged behind the change of rheological properties.
    Resistance and cooling performance of ceiling cooling panel of capillary porosity wick
    HU Peng,TONG Mingwei,CHEN Cai,YU Jiajia,WANG Xi,SUN Yahui
    2012, 63(1):  59-63.  doi:10.3969/j.issn.0438-1157.2012.01.008
    Abstract ( 2069 )   PDF (407KB) ( 749 )  
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    Since conventional air-conditioning consumes more energy and the temperature in a room is non-uniform,a new ceiling cooling panel of capillary porosity wick(CCPCPW),which is configured by porous media of potassium citrate-gypsum,is used when water is the cooling medium.The CCPCPW with porosity of 55.3% was studied experimentally.The structure and different configurations of CCPCPW were presented and the cooling performance was tested when maintaining the indoor temperature distribution at (26±1)℃,and the relationship of flow rate and resistance was analyzed.The results show that the cooling capacity of the CCPCPW is increased by 36.6%—57.7% when the inlet temperature of cooling water is 10—16℃.The viscous force and friction factor gradually decrease and the permeability increases when the flow rate of cooling water is within 4—28 L·h-1,but the permeability is decreased when the flow rate is within 28—40 L·h-1,which indicates that the local resistance of curve part of pore channel is increased because of higher flow velocity.
    Nucleate pool boiling heat transfer of δ-Al2O3-R141b nanofluid on horizontal plate
    TANG Xiao,DIAO Yanhua,ZHAO Yaohua,ZHANG Ji
    2012, 63(1):  64-70.  doi:10.3969/j.issn.0438-1157.2012.01.009
    Abstract ( 2335 )   PDF (1070KB) ( 680 )  
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    Heat transfer performance of nanofluids in nucleate pool boiling was experimentally investigated on a horizontal flat surface of cooper under atmospheric pressure.The surface roughness was controlled by sandpaper of grade 2000#.The nanofluid was prepared by dispersing the δ-Al2O3 nanoparticle in the base fluid refrigerant 141b(R141b) in 0.001%,0.01% and 0.1% volume fractions.The results show that the heat transfer coefficient increases with the concentration of nanoparticle.Compared with the pure fluid R141b,the heat transfer coefficient is increased 50.2% for 0.1% volume fraction averagely under 30—130 kW·m-2 heat flux.The surface deposition of particles is observed as one of the major factors for the enhancement.For pure R141b and low concentration nanofluid,the experimental results agreed well with the predictive results based on Rohsenow’s correlation.The maximum relative error is less than 13%.At higher concentrations,the correlation is no longer applicable.
    Vortical flow and heat transfer characteristics in rectangular channel with trapezoidal tab
    TANG Xinyi,ZHU Dongsheng,CHEN Hong
    2012, 63(1):  71-83.  doi:10.3969/j.issn.0438-1157.2012.01.010
    Abstract ( 2136 )   PDF (12800KB) ( 481 )  
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    The heat transfer and flow characteristics of trapezoidal tab with and without clearance are analyzed by Realizable k-ε turbulent model.The effects of clearance location and flow direction on the thermal performance of rectangular channel are studied to understand the mechanism of heat transfer enhancement induced by all kinds of vortices behind the tab.The mechanism of heat transfer enhancement is understood from the analysis on parameters,such as vorticity magnitude,streamlines,velocity profiles,pressure variations and turbulence intensity.The results show that Nusselt number and friction factor of backward flow are 21.7% and 25% higher than that of forward flow,respectively.The tab with inside clearance shows higher heat transfer coefficient and higher friction drag,while the tab with outside clearance exhibits lower heat transfer coefficient and lower form drag.The overall performance analysis for rectangular channel with tab shows that tab with or without clearance is competitive with other conventional turbulators,especially in its low power consumption.At lower Reynolds number(10000<Re<14000),the overall performance for backward flow is about 6.7% higher than that for forward flow. However,at higher Reynolds number(14000<Re<20000),the tab with clearance shows better overall performance.Due to Kelvin-Helmholtz instability,the hairpin vortex induced by the free shear layer shed from the tip of tab generates high turbulence intensity,which enhances fluid mixing.The pressure difference generated by the high-momentum fluid in the bulk region and the low-momentum fluid in the wake of tab produces two longitudinal vortex pairs named as primary counter-rotating vortex pairs(CVP) and secondary CVP.The reverse vortices are formed by recirculation induced by adverse pressure gradient behind the tab.Longitudinal vortices intensify the convective transportation between the base wall and flow center.Thus,the heat transfer intensification is mainly due to the counter-rotating longitudinal vortices and hairpin vortex,which produces a swirling motion.The two inflections of velocity profiles are caused by the hairpin vortex and reverse vortex,separately.
    Hydrodynamics and mass-transfer of tridimensional parallel flow trays
    WANG Shengkun,ZHANG Jijun,ZHANG Shaofeng
    2012, 63(1):  84-89.  doi:10.3969/j.issn.0438-1157.2012.01.011
    Abstract ( 1483 )   PDF (598KB) ( 374 )  
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    Parallel flow trays have attracted considerable attention to its high mass-transfer efficiency.The new tridimensional parallel flow tray with continuous mass-transfer combines two parallel flows and LLC-tray(LLCT).The hydrodynamic characteristics of the tray,such as dry-pressure-drop,wet-pressure-drop,entrainment and weeping,and mass-transfer efficiency were measured and relevant correlations were obtained.The pressure drop and entrainment of the tray were lower.In a certain range of liquid flux,the effect of liquid flux on entrainment was negligible.When the gas velocity decreased to a critical point(the gas velocity through the plate hole was about 12 m·s-1),the weeping of ring flow started earlier than the converged flow.The liquid flow rate was 30% higher than that with LLCT because the parallel flow tray avoided the liquid stagnation zone on common countercurrent trays.With several downcomers the flow distance of liquid was shorter and the gradient of liquid level was reduced.The mass transfer efficiency of the tray was higher than that of LLCT and the efficiency of ring flow was higher than converged flow because of different length of liquid passage.
    Influence of surface physical and chemical inhomogeneities on heat transfer characteristics of steam condensation
    RUAN Yiping,ZHANG Li,XU Hong
    2012, 63(1):  90-95.  doi:10.3969/j.issn.0438-1157.2012.01.012
    Abstract ( 2081 )   PDF (1040KB) ( 560 )  
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    Visual experiments were employed to investigate wettability and heat transfer characteristics of steam condensation on vertical copper plates with different surface roughness by grinding.Effects of surface roughness and oxidation-induced chemical inhomogeneity on wettability and heat transfer characteristics of steam condensation were analyzed.The results indicate that the contact angle increases to a maximum value when the surface roughness reaches 0.15 μm and then decreases with increasing surface roughness.Moreover,chemical inhomogeneity induced by oxidation during steam condensation on the modified surface always contributes to enlarge contact angle and thus increase hydrophobic property.The results suggest that the wettability and steam condensation mode on the copper surface are determined by micro-scale surface roughness and chemical inhomogeneity.The experimental results show that the oxidized surface with surface roughness of about 0.15 μm exhibits complete dropwise condensation,increasing condensation heat transfer coefficient by a factor of 3.5 compared to complete filmwise condensation,but a surface with larger roughness will inhibit the drops to depart from the condensing surface and hence reduce the condensation heat transfer coefficient,so that the condensation heat transfer of the surface with roughness of 0.09 μm is larger than that with surface roughness of 0.15 μm.
    Intermediate pressure and its effect on performance of two-stage compression system with variable operating mode
    JIN Xu1,WANG Shugang1,ZHANG Tengfei1,LI Zhaoyi2,ZU Feng1
    2012, 63(1):  96-102.  doi:10.3969/j.issn.0438-1157.2012.01.013
    Abstract ( 1722 )   PDF (453KB) ( 544 )  
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    A dynamic coupled model of a two-stage compression system with variable capacity reflecting the generation of intermediate pressure is constructed based on the rotary compressor geometry,the mass and energy conservation equations.The model is verified by the experiment.According to the results of simulation and experiment,the variation of the intermediate pressure with time and characteristics of variable operating modes were analyzed.The results show that the intermediate pressure has pulse characteristics,but the pulse amplitude is relatively small by comparison to the time-averaged value.Among the factors affecting the intermediate pressure,the ratio of theoretical displacement of the low compressor to that of the high one is the most significant one and condensation temperature is less significant than evaporation temperature.The heating capacity increases linearly with the intermediate pressure,while the change of the system COP for heating increases with intermediate pressure first and then decreases,and there exists an optimal value.
    CFD analysis of wall effects in packed beds with small tube-to-sphere diameter ratio
    GUO Xueyan,CHAO Donghai,CHAI Huisheng,YANG Fan
    2012, 63(1):  103-108.  doi:10.3969/j.issn.0438-1157.2012.01.014
    Abstract ( 1841 )   PDF (1535KB) ( 449 )  
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    Strong wall effects exist in packed beds with small tube-to-sphere diameter ratios because of the large void fraction near the wall,and the flow characteristics are of fundamental interest and valuable for engineering applications.CFD simulation was conducted to analyze the complex flow fields in three different packed bed models.Detailed investigation was carried out into the non-homogeneity resulting from wall effects.Based on two geometric models containing same number of spheres but packed randomly and in structure respectively,flow fields and especially near wall local flows were studied.Flow rate distribution on the transversal sectional planes determined by the large void fraction near wall was quantitatively investigated.It was found that flow rate through an annular area of 1/4 sphere radius wide near the wall was as high as 40% of the total flow rate,in a random packed bed with D/d=7.By intentionally increasing the near wall gap of the random bed and structured bed to half of sphere radius both containing 244 spheres,wall effects were analyzed quantitatively and the near wall flow rate was found to be as high as 60% of the total flow rate(structured bed 61% and random bed 74%).The pressure drop in the two packed beds was found obviously higher than predicted with Ergun correlation,which was believed to be the contribution of viscous energy loss resulting from wall effects.The results might imply that wall effects in a packed bed with excessively large near-wall void fraction deteriorated the transport performance and reaction efficiency since no adequate fluid flowed through the core region in the bed.
    Molecular dynamics simulation for diffusion of organic molecules in polyethylene membranes
    YUE Yajuan, LIU Qingzhi, WU Lianying, HU Yangdong
    2012, 63(1):  109-113.  doi:10.3969/j.issn.0438-1157.2012.01.015
    Abstract ( 2580 )   PDF (800KB) ( 884 )  
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    The diffusion of benzene,toluene and ethylbenzene in amorphous polyethylene(PE) membrane was studied in this paper,and their diffusion coefficients were analyzed and calculated by molecular dynamics simulation.The diffusion coefficients were calculated with the clustering method.The calculated results have the same trend with experimental results: the diffusion coefficient decreases with increasing molecular weight of organic molecules at the same temperature and increases with temperature for the same organic molecule.It is shown that the diffusion coefficients are reasonable and reliable.The diffusion behavior of three kinds of molecules in polyethylene membrane in a long time(300 ps) scale was simulated and the tracks of molecules were obtained,which show that the molecule movement in the membrane is local vibration combined with prancing diffusion.
    Catalyzed transformation of saccharides in ionic liquids to synthesis lactic acid
    HUANG Jiaruo,LI Wensheng,ZHOU Xiaoping
    2012, 63(1):  114-120.  doi:10.3969/j.issn.0438-1157.2012.01.016
    Abstract ( 2680 )   PDF (431KB) ( 603 )  
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    Methyl lactate and lactic acid were synthesized by hydrolysis of starch and cellulose using SnCl4 catalyst.The use of ionic liquids as the solvent was the key factor for the successful hydrolysis.The influence of catalyst,type of ionic liquids,reaction temperature and time on the product yield were investigated.The results indicated that methyl lactate and lactic acid can be obtained via liquid phase transformation catalyzed by SnCl4 in 1,3-dimethylimidazolium methylsulfate ionic liquid at 140℃ for 2 h,the yield was 54% for starch and 15.1% for cellulose conversion.Fructose could be directly converted to lactic acid with almost stoichiometric yield,but only 64% for glucose.So,starch and cellulose were firstly catalyzed degradation to glucose that then was isomerized to fructose,and fructose decomposed to lactic acid finally.
    Hydrogenation of nitrobenzene to aniline on amorphous Ni-Mo-P catalysts and mechanism of catalyst deactivation
    LIU Zili1,2,QIN Zuzeng2,ZHANG Jianjie1,WANG Yanhua2
    2012, 63(1):  121-126.  doi:10.3969/j.issn.0438-1157.2012.01.017
    Abstract ( 3682 )   PDF (651KB) ( 676 )  
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    The process of nitrobenzene hydrogenation to aniline using an amorphous Ni-Mo-P alloy as the catalyst and the deactivation mechanism of the amorphous Ni-Mo-P alloy catalyst were studied. Investigation of the effects of reaction time,temperature,and hydrogen pressure on nitrobenzene hydrogenation to aniline using the Ni-Mo-P catalyst revealed optimum conditions as 90 min,383 K,and 1.8 MPa.Under these conditions,the yield of aniline reached 98.2% using the amorphous Ni-Mo-P catalyst after nitrobenzene hydrogenation for 15 h,indicating excellent activity stability of the amorphous Ni-Mo-P catalyst.Deactivation of the amorphous Ni-Mo-P catalyst was due mainly to nitrobenzene hydrogenation byproducts covering the catalyst activity sites,which made it difficult for reactant molecules to access the catalyst activity sites and was highly unfavorable to the catalytic reaction.
    Preparation of Cu/ZnO/Al2O3 catalysts via mechanical milling and combustion method for methanol synthesis
    LEI Hong1,2,LIN Xiaoxiao1,HOU Zhaoyin2
    2012, 63(1):  127-132.  doi:10.3969/j.issn.0438-1157.2012.01.018
    Abstract ( 2284 )   PDF (684KB) ( 652 )  
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    Cu/ZnO/Al2O3 catalysts were prepared by mechanical milling and combustion at different calcination temperatures and were tested for the synthesis of methanol from CO hydrogenation.Calcination of catalyst precursors was monitored with thermogravimetry differential scanning calorimeter(TG-DSC).These catalysts were characterized by X-ray diffraction(XRD),scanning electronic microscope(SEM),N2 adsorption,temperature-programmed reduction with H2(TPR) and N2O oxidation followed by H2 titration.The results showed that the physicochemical properties of the prepared catalysts depended strongly on calcination temperature,and BET surface area and dispersion of copper species decreased with increasing calcination temperature.The catalyst calcined at 350℃ exhibited the highest activity and stable catalytic performance.The method could be a promising alternative for the preparation of highly efficient Cu/ZnO/Al2O3 catalysts.
    Preparation of macroporous β-cyclodextrin matrix and its adsorption behaviors for rutin
    MA Chunyan, LIN Dongqiang, YAO Shanjing
    2012, 63(1):  133-138.  doi:10.3969/j.issn.0438-1157.2012.01.019
    Abstract ( 2078 )   PDF (707KB) ( 584 )  
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    A series of novel macroporous β-CD-EP(M-CD-EP) composite matrix with a suitable particle size distribution for chromatography were prepared by the reversed-phase suspension crosslinking technique using epichlorohydrin as a crosslinking agent and calcium carbonate as a porogenic agent.For comparison,the homogeneous(H-CD-EP) beads were also fabricated without calcium carbonate.The photographs got by scanning electron microscope indicated that the M-CD-EP particles have spherical appearance with some “pits” on the surface.As a result,the porosity and water content of M-CD-EP matrix are higher than that of H-CD-EP matrix.Besides,the static and dynamic adsorption performances of the matrices for rutin were also studied.The results showed that more rutin was adsorbed and there was higher adsorption rate for M-CD-EP medium than for H-CD-EP one.The pore diffusivity of rutin in the M-CD-EP beads is two to three times as big as the H-CD-EP beads.
    Synthesis and identification of functional ionic liquids and research on its performance of CO2 absorption
    LIU Weiwei1,HU Song1,CHEN Wen2,XIANG Jun1,SUN Lushi1,SU Sheng1
    2012, 63(1):  139-145.  doi:10.3969/j.issn.0438-1157.2012.01.020
    Abstract ( 2778 )   PDF (1355KB) ( 674 )  
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    Two kinds of traditional ionic liquids([bmim]BF4,[emim]BF4) and three kinds of functional ionic liquids containing amino group and hydroxy group([NH2P-mim]Br,[NH2-e-mim]BF4,[OH-e-mim]Br) were synthesized.IR,1H NMR were used to determine the structures and properties of these ionic liquids.CO2 adsorptive experiments were made in a laboratory bench-scale system with the ionic liquids at atmosphere pressure and room temperature to determine the parameters of the CO2 saturated adsorption and its adsorptive balance time.Comparing the differences of CO2 adsorptive performance with the functional and traditional ionic liquids,it was found that CO2 saturated adsorption capabilities of the functional ionic liquids with amino group([NH2P-mim]Br,[NH2-e-mim]BF4) and hydroxyl group([OH-e-mim]Br) were 3—9 times and 1—2 times greater than the unmodified ionic liquid respectively,the functional ionic liquids containing ethyl functional groups always had shorter adsorption balance time.Finally,the influence of the temperature and CO2 partial pressure on the process of functional ionic liquid adsorption of CO2 was discussed.
    Temperature measuring point analysis and control system design of heat exchanger networks based on structural observability
    LUO Xionglin1,HOU Benquan1,SUN Lin1,2
    2012, 63(1):  146-156.  doi:10.3969/j.issn.0438-1157.2012.01.021
    Abstract ( 2248 )   PDF (748KB) ( 430 )  
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    For the large scale heat exchanger networks(HEN),there are a mass of coupled temperatures. If these states cannot be controlled and observed,it will go against saving energy and safety in production.To implement control system,placing the temperature measuring points in the HEN properly is the basis.Generally,too many thermocouples are set by experience to ensure all states of the HEN are observable.But it is not cost-efficient and lack of verification by the control theory.Therefore,it is necessary to develop a method to design temperature measuring points of HEN based on the control theory. An optimal design method of temperature measuring points with all states observable was proposed by using structural observability and analysis of the impact of bypasses.The design could maintain all of states observable and minimize the number of temperature measuring points with the trade-off between observability and capital investment.With measuring points determined,the regulatory control system was proposed based on the relative gain array analysis.Consequently,a case study with HEN in a crude distillation unit demonstrated the effectiveness of the method proposed.
    Micro injection molding simulation based on SPH method
    ZHANG Xiang1,2,LI Qian1,SHI Fan1, SHEN Changyu1
    2012, 63(1):  157-162.  doi:10.3969/j.issn.0438-1157.2012.01.022
    Abstract ( 2368 )   PDF (1992KB) ( 457 )  
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    Micro injection molding is an efficient and low cost process for the large-scale replication of thermoplastic polymer microparts.Numerical simulation in cavity filling is important to mold design and process parameters setting before mold manufacture.A meshfree-based method for solving viscosity equations was proposed to simulate the filling process of micro injection molding.The N-S governing equations were discretized by using a particle approximate method of smooth particle hydrodynamics.Some physical properties,such as velocity,pressure,and temperature were investigated in the filling process.As an example,mold cavity filling simulation for a microneedle used in biomedical application was performed,and the results were consistent with experiment.Compared with the traditional mesh method,such as three dimensional finite element method,with corresponding node or particle number and process condition,the proposed meshfree method showed advantages of higher accuracy and calculation efficiency.
    Integration of refinery hydrogen network with multiple impurities
    LIU Guilian1,LIU Yongbiao1,2,FENG Xiao1
    2012, 63(1):  163-169.  doi:10.3969/j.issn.0438-1157.2012.01.023
    Abstract ( 2147 )   PDF (986KB) ( 535 )  
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    The evolutionary method is applied to optimize the hydrogen network with multiple impurities. With every match possibility and the complementary advantage of source streams considered,the maximum match flow rate matrix(M matrix),potential match flow rate matrix(P matrix),and optimal match flow rate matrix(O matrix) are determined in turn.The results shows that the minimum hydrogen utility consumption of this system is 1495.83 m3·h-1.Compared with the current hydrogen utility consumption,the saving potential is 1004.17 m3·h-1,accounting for 40.2% of the utility consumption. Furthermore,the optimal network is determined according to the O matrix.
    Quantitative analysis of the capability of resistance to disturbance of stable steady-state points
    WANG Hangzhou,CHEN Bingzhen,QIU Tong,ZHAO Jinsong,HE Xiaorong
    2012, 63(1):  170-176.  doi:10.3969/j.issn.0438-1157.2012.01.024
    Abstract ( 1921 )   PDF (866KB) ( 453 )  
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    In order to increase the safety of chemical process,researchers proposed many methods and strategies,some quantitative indices have been developed to describe the potential hazard and dangerous of different reaction route and reactant.In this paper,the stability was considered as a factor to indicate the process safety,and a quantitative analysis of the capability of resistance to disturbance of stable steady-state points were conducted,then the fermentation process and MMA process were studied to demonstrate the effectiveness of the proposed method.
    Design,simulation and optimization of fully thermally coupled distillation column
    GONG Chao,YU Aiping,LUO Yiqing,YUAN Xigang
    2012, 63(1):  177-184.  doi:10.3969/j.issn.0438-1157.2012.01.025
    Abstract ( 2495 )   PDF (453KB) ( 628 )  
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    A short-cut design method based on Fenske-Underwood-Gilliland equations for fully thermally coupled distillation column is proposed.The approach uses a shortcut method that estimates the initial specifications for the theoretical tray numbers,feed and liquid withdraw locations and the reflux ratio.By the rigorous simulations,the overhead fraction of the distributed component,as well as the split ratios for the gas and liquid phases Rv and Rl are optimized.And the influence of parameters βRv and Rl on the reboiler duty are also found respectively.
    Simulation and optimization of acetylene converter with decreasing catalyst activity
    TIAN Liang1,2,JIANG Da1,QIAN Feng1
    2012, 63(1):  185-192.  doi:10.3969/j.issn.0438-1157.2012.01.026
    Abstract ( 2451 )   PDF (1265KB) ( 520 )  
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    Since the activity and selectivity of acetylene hydrogenation catalyst change with time,the operating parameters need to be changed to maximize the profit.Therefore,we collected the industrial process data and estimated the parameters of kinetic model and deactivation model by genetic algorithm.We compared the selectivity and activity performance of two commonly used catalysts.For two reactors in series filled with different catalysts,we proposed the methods of combinatorial optimization and ratio assignment to optimal ethylene production rate.When these optimization strategies were implemented in the actual plant,ethylene production rate and the total selectivity increased significantly.
    A stair-like generalized predictive control algorithm based on multiple models switching
    LI Xiaotian1,WANG Xin2,WANG Zhenlei1,QIAN Feng1
    2012, 63(1):  193-197.  doi:10.3969/j.issn.0438-1157.2012.01.027
    Abstract ( 2082 )   PDF (354KB) ( 590 )  
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    A stair-like generalized predictive control algorithm based on multiple models switching is proposed for systems with jumping parameters.Multiple fixed models,a conventional adaptive model and an assigned initial value adaptive model are established to identify dynamic characteristic in parallel. Multiple fixed models can improve transient performance,conventional adaptive model can ensure the stability of systems and assigned initial value adaptive model can further enhance transient performance.The best sub-model is selected as global model according to the switching index,and a stair-like generalized predictive controller is designed for this model.Consequently,the full-range operation is achieved.Finally,simulation shows that the control effect of proposed method is superior to a single controller.
    Integrated process of electrochemical hydrogengation and electrooxidation of diesel oil
    LIU Changjian1,LI Debao2,YANG Shicheng3,LI Weibin3,HU Sheng3,ZHANG Zhihua3
    2012, 63(1):  198-202.  doi:10.3969/j.issn.0438-1157.2012.01.028
    Abstract ( 1945 )   PDF (380KB) ( 434 )  
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    Due to the future specifications for sulfur and polyaromatic content in diesel,the traditional hydrotreatment process was confronted with the difficulty to fulfill this target for the steric hindrance of polyaromatic sulfur compounds such as dibenzothiophene(DBT) and its derivatives,lead to their slow reactivity with catalysts.An alternative method for desulfurization was the oxidation and extraction removal of sulfur compounds,but the polyaromatic content remained the original content.A new integrated process was studied in which the electrochemical hydrogenation of polycyclic aromatics and electrooxidation of sulfur compounds in diesel oil could be integrated in CH3CN+EtOH+H2O+Bu4NBr electrolysis system with spumous Pb as cathode and graphite as anode.The electrochemical hydrogenation was mild,the content of H for diesel increased 1.1%,the content of polycyclic aromatics decreased 3.3%,cetane increased 3.9.The sulfur compounds in diesel oil were oxidized,the sulphone compounds were not extracted into electrolysis system completely,further by adsorption with activated carbon,the sulfur content decrease from 884 μg·g-1 to 44 μg·g-1.
    Consequence analysis strategy for mal-operation in batch processes based on qualitative simulation
    ZHANG Yuliang,ZHANG Beike,MA Xin
    2012, 63(1):  203-215.  doi:10.3969/j.issn.0438-1157.2012.01.029
    Abstract ( 1581 )   PDF (469KB) ( 394 )  
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    Mal-operation is one of important factors that lead to disaster in chemical processes.Batch processes with a lower level of automation require many manual operations.These manual operations make increased occurrence of mal-operation possible.Therefore,it is necessary to analyze the effects of mal-operation on the batch process so that protective measures can be effectively taken.To achieve this aim,a novel consequence analysis strategy for mal-operation in the batch processes was proposed.Qualitative models of manual operation,production process,and environment were constructed by using the concept of qualitative simulation.These models could describe the batch process more satisfactorily.Qualitative model of environment and every qualitative model describing the production process,such as a qualitative model of pump or reactor,had the faculty of inference,which enabled these models to update their states and infer whether some hazards would occur by themselves when an operation was being dealt with.A batch process that produced vulcanization accelerator called M was modeled,and three wrong operating procedures were analyzed.The results showed that not only adverse consequences but also evolution of abnormal states in the batch process caused by mal-operation could be analyzed by using the proposed method.
    Preparation of chitosan-NaCS/TPP microcapsule with uniform size by microfluidic chip
    LIU Chuan,ZHU Liying,LIN Dongqiang,YAO Shanjing
    2012, 63(1):  216-222.  doi:10.3969/j.issn.0438-1157.2012.01.030
    Abstract ( 2455 )   PDF (1569KB) ( 888 )  
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    Microfluidic chip emulsification with the cross-junction microchannel is a relatively new technique for preparing water-in-oil and oil-in-water emulsions,as well as the monodisperse microparticles after curing of the emulsion droplets.In the present work,with chitosan,sodium cellulose sulfate(NaCS) and tripolyphosphate(TPP) as raw materials,the chitosan-NaCS/TPP microcapsules were prepared by a cross-flow microfluidic chip.The width and height of microchannel is 200 μm and 1 mm,respectively.Different flow states were observed in the microchannel,and the capillary number Ca was used to identify the laminar,plug and droplet flows to control the formation of microdroplets.The effects of dispersant and chitosan concentration,flow rates of oil phase and water phase on the preparation of microdroplets were investigated.The optimized preparation conditions was 2% chitosan as water phase,liquid paraffin containing 5% Span 85 as oil phase,the flow rate of water phase of 5 μl·min-1 and the ratio of oil phase to water phase at the range of 40—100.The microdroplets of chitosan solution could be obtained with uniform size,and the variation coefficient was less than 0.1.Then the microdroplets of chitosan solution were reacted with the solution of 1% NaCS and 3% TPP,and the chitosan-NaCS/TPP microcapsules with uniform size were obtained.Novel chitosan-NaCS/TPP microcapsules showed a special structure with the double-layer membrane,which have the potential applications as the drug carrier.The results demonstrated that the microfluidic chip could control the size of microdroplets and prepare the monodispersed microcapsules.
    Strategy for enhanced co-production of S-adenosylmethionine and glutathione by Candida utilis based on energy metabolic analysis
    WANG Yulei,WEI Gongyuan,SHAO Na,NIE Min
    2012, 63(1):  223-229.  doi:10.3969/j.issn.0438-1157.2012.01.031
    Abstract ( 2009 )   PDF (486KB) ( 600 )  
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    The concentrations of intracellular co-factors,such as ATP,ADP,NADH and NAD+ vital for energy metabolism within Candida utilis CCTCC M 209298 were measured by HPLC.Based on the levels of co-factors,especially ATP during batch cultivation of C.utilis CCTCC M 209298,we developed a novel culture strategy of L-cysteine addition followed by ATP accumulation(21 h) instead of cell growth ceased(15 h) for further enhanced co-production of S-adenosylmethionine and glutathione using energy metabolic analysis.Subsequently,we combined this strategy with high-cell-density culture of C.utilis CCTCC M 209298,and both high biomass and high co-production of S-adenosylmethionine and glutathione were achieved.The culture strategy under the guidance of ATP concentration was proved to be efficient in terms of full utilization of intracellular residual ATP,together with improvement of co-production of S-adenosylmethionine and glutathione,and the co-production of S-adenosylmethionine and glutathione attained 584.7 mg·L-1 and 1004.4 mg·L-1 from batch and fed-batch fermentation,which were 27.1% and 26.4% higher than the controls,respectively.The results presented in this study provide a feasible strategy for optimization of fermentative processes for enhancing the co-production of analogous useful chemicals biosynthesized by consuming energy.
    Evolution of biofouling on a vertical stainless steel surface caused by bacillus subtilis under heat pump conditions
    TIAN Lei, YANG Qianpeng, SHI Lin, CHEN Jinchun
    2012, 63(1):  230-236.  doi:10.3969/j.issn.0438-1157.2012.01.032
    Abstract ( 1832 )   PDF (1131KB) ( 552 )  
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    Treated sewage is an important carrier of urban waste energy,which can be used as a suitable heat source in heat pump systems.A treated sewage source heat pump system was designed and used at Beijing Olympic Village in 2008 to provide heating and cooling,which is a green approach to recovering urban heat.However,treated sewage contains components that can cause fouling,such as heterotrophic bacteria,microbial nutrients and suspended substances.These could not be completely removed during treatments conducted by the wastewater treatment plants,and biofouling inevitably occurs in the plate heat exchangers of the treated sewage used in the heat pump systems.In order to understand the characteristics of the biofouling,an experimental system,which mimicked the treated sewage water and simulated the relevant fouling formation process,was developed in our laboratory.The flow cell in the system,which was used to imitate plate heat exchangers,allowed sample surfaces properly retrieved and analyzed.Extensive experimentations including process monitoring and microstructure development in biofilm were conducted and the results presented in this paper showed the possibility of reducing the biofouling in the future.Under typical heating and cooling conditions of heat pump,the growth curves of biofouling were generated from different weight values,the micromorphic evolution of biofouling was characterized by using Environmental Scanning Electron Microscopy.A series of quantitative information was obtained and discussed.In particular,the effects of flow velocity and bacterial concentration were investigated,which clearly influenced the biofilm development,thus impacting the thermal resistance created.It was found that the biofouling growth rate changed synchronously with the micromorphic evolution,and the effect of flow velocity on biofouling formation was non-monotonic.Biofouling would be neglected when the bacterial concentration decreased to 103 CFU·ml-1(CFU,colony formine unit).The results are instructive to choose the cleaning time points and develop mitigating and cleaning technology.
    Experiment of pulsation hydrogen passing into PEMFC
    WANG Xiaoshan1,ZHANG Jinfang1,ZHANG Caizhi2,HAN Ming2
    2012, 63(1):  237-243.  doi:10.3969/j.issn.0438-1157.2012.01.033
    Abstract ( 1980 )   PDF (2350KB) ( 593 )  
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    Using the experimental platform set up with a home-made PEMFC and other related equipment,three group experiments are designed and conducted,which associated with the factors affecting output performance of PEMFC,that is the location and pressure of pulsating hydrogen as well as regulation of load voltage to investigate the relationship between output current and time in the fuel cell at constant potential mode.The experimental results indicate that pulsation boosts the output current better than the frequent purge process; it is more beneficial to apply pulsation to the anode channel outlet rather than the inlet; the output current increases with the pressure of the pulsating reactant gas; If the required load voltage is high enough,the purge process in the system with pulsation can be canceled; at a certain load voltage level,the output current and its stability may be adjusted to the optimum by means of proper pulsation parameters.
    Pollution feature and characteristic pollutants of bleaching effluent of southern hardwood chemical pulp
    LEI Lirong1,2,LI Youming1,2,MA Liming1
    2012, 63(1):  244-250.  doi:10.3969/j.issn.0438-1157.2012.01.034
    Abstract ( 2212 )   PDF (419KB) ( 558 )  
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    Pollution feature and characteristic pollutants of bleaching effluent of southern hardwood chemical pulp were investigated by using the data obtained from conventional analysis,infrared(IR) and ultraviolet(UV) spectrum,gas chromatography(GC)- mass spectrometry(MS).It was found that in the effluent the concentration of dissolved organic compounds is high and its biodegradability bad,CODCr(dissolved chemical oxygen demand) and BOD5(dissolved biochemical oxygen demand) 1.5 kg·m-3 and 0.4 kg·m-3 respectively,and BOD5/CODCr 0.27.The data from IR and UV spectra indicates that the organic pollutant structures in the effluent contain benzene ring,carbonyls that are chromophore groups,and hydroxyls,ethers and carboxyls which are auxochromous groups.The deep color of effluent can be attributed to these compounds containing these groups as well as conjugation structures between carbonyl groups and C=C double bonds.An analysis for the data from of GC-MS shows that there are a large number of complicated organic pollutants in the effluent,including lipoid substances,phenols,alkanes and organic acids,aromatic compounds,and their relative peak area is up 58.16%.Based on photobacterium EC50 of the major organic compounds measured,the characteristic pollutants to be controlled for bleaching effluent of southern hardwood chemical pulp should include phenols,chlorophenols,organic chlorides and phthalates.
    Characteristics and factors influencing denitrification and dephosphorization in sequencing batch moving bed biofilm reactor
    GUO Haiyan, GUO Zhen, FENG Tengteng, ZHANG Shoutong, ZHOU Jiti
    2012, 63(1):  251-257.  doi:10.3969/j.issn.0438-1157.2012.01.035
    Abstract ( 2169 )   PDF (496KB) ( 624 )  
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    In this paper,the effect of aeration rate,C/N ratio and the concentration of nitrogen and phosphorus at inflow point on the performance of a sequencing batch moving bed biofilm reactor(SBMBBR) was studied,and the mechanism of pollutants removal for hybrid microorganism system was also discussed.The experimental results demonstrated that nitrogen removal took mainly place in aerobic phase by simultaneous nitrification and denitrification(SND),while phosphorus removal carried out by conventional bio-dephosphorization and denitrifying phosphorus removal.The fluidized state of bed and DO concentration in the mixed liquid were affected by aeration rate.If good fluidized state could be kept(4.8—9.0 L·L-1·h-1 of aeration rate),denitrification could be improved with aeration rate decreased,while for nitrification and TP removal there was no obvious effect.If anaerobic/oxic sequencing batch operation mode was adopted,organics in influent water could be preferentially utilized by denitrifying phosphorus accumulating organisms,and the need of extra carbon for denitrification could be decreased.At 2.8—4.0 of C/N ratio in influent water a good nitrification,denitrification and TN removal could be obtained,and at 1.5 of C/N ratio,efficiency of denitrifying and TP removal deteriorated,at 7.4,both that of nitrifying and denitrifying decreased.With rising of nitrogen and phosphorus concentrations at inflow point,rate of phosphorus removal was not change while nitrogen removal poor,the maximum rate was 0.17 kg TN·m-3·d-1 and 0.06 kg TP·m-3·d-1 for nitrogen and phosphorus removal,respectively.
    Content determination of phenolic hydroxyl and carboxyl in lignin by aqueous phase potentiometric titration
    ZHOU Mingsong1,2,HUANG Kai1,2,QIU Xueqing1,2,YANG Dongjie1,2
    2012, 63(1):  258-265.  doi:10.3969/j.issn.0438-1157.2012.01.036
    Abstract ( 4479 )   PDF (447KB) ( 1137 )  
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    The potentiometric titration in aqueous phase is used for determination content of phenolic hydroxyl and carboxyl on alkali lignin(AL) and sodium lignosulphonate(SL).The results show that the content of phenolic hydroxyl and carboxyl are 2.81 mmol·g-1 and 1.72 mmol·g-1 for AL,and 1.32 mmol·g-1 and 0.86 mmol·g-1 for SL,respectively.A comparison with classical non-aqueous potentiometric titration indicates that the stability is more excellent for the measurement in aqueous phase.The dynamic light scattering(DLS) method is used for the study of hydrodynamic diameter distributions of AL and SL in DMF and water solvents.The results show that they have stronger aggregation in DMF than in alkaline water,indicating that there is better dissolubility in alkaline aqueous solution than in DMF solvent.Therefore,it can be considered that the aqueous potentiometric titration is more suitable for the quantitative determination of phenolic hydroxyl and carboxyl contents on lignin-based compounds and can be an option for quantitative determination of the functional groups on lignin.
    Methane oxidation with in situ enhanced facultative bacteria from aged-refuse
    ZHAO Tiantao1,2,ZHANG Yunru1,ZHANG Lijie1,QUAN Xuejun1,PENG Xuya2
    2012, 63(1):  266-271.  doi:10.3969/j.issn.0438-1157.2012.01.037
    Abstract ( 2272 )   PDF (1216KB) ( 612 )  
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    Facultative methanotrophs can utilize methane as well as multi-carbon compounds,including organic acids and carbohydrates.Facultative methanotrophs from aged-refuse were enhanced in situ to overcome the limitations of methane oxidation by existing landfill covers.Methanotrophs from oligotrophic aged-refuse had a better environmental tolerance by analysis of scanning electron microscope(SEM).These bacteria could enrich quickly in the presence of carbon source.However,the methane-oxidation capability could not be improved if only adding carbohydrates or nitrate mineral salts(NMS) medium alone.Compound acclimation of facultative methanotrophs were carried out by NMS medium and glucose/starch.After a delay period of 7—9 d,methane consumption came into a logarithmic growth period,which indicated that facultative methanotrophs had strong biological activity and high substrate competitive advantage.Metabolic pathways of facultative methanotrophs were modified by adding NMS medium,and methane could be utilized despite the presence of other carbon sources.The activity of facultative methanotrophs was enhanced by low concentration of chloroform.Oxidation rate of methane reached 0.114 ml·d-1·g-1 as the concentration of chloroform was 50 mg·L-1.The problems about the engineering application of obligate methanotrophs were overcome due to the discovery of the new method,and the results would have important implication for understanding the methane-oxidizing bacteria and the factors controlling methane fluxes in the environment.
    Removal of para-chloronitrobenzene in water by FeOOH/H2O2
    ZHU Jiayi, SHEN Jimin, CHEN Zhonglin, GAO Guoying, HAN Ying
    2012, 63(1):  272-278.  doi:10.3969/j.issn.0438-1157.2012.01.038
    Abstract ( 2081 )   PDF (498KB) ( 524 )  
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    Synthetic goethite(FeOOH) prepared in laboratory was evaluated for FeOOH/H2O2 catalytic activity removing para-chloronitrobenzene(p-CNB) in water.The pathway of degradation was deduced from the effect of tert-butanol on the catalytic reaction and the performance comparison with some related reactions.Effects of catalyst and oxidant doses,as well as the factors associated with water quality such as initial pH of solution,HCO-3 alkalinity and humic acids,on p-CNB removal in FeOOH/ H2O2 system were also examined.The results show that FeOOH has high catalytic activity on H2O2 decomposition for removing p-CNB in water.Tert-butanol could effectively inhibit the oxidation of p-CNB in FeOOH/H2O2 system,indicating the catalytic oxidation reaction follows a hydroxyl radical pathway.Under the optimal reaction conditions of pH value in the range of 4.0—6.0,dosage of 333 mg·L-1 FeOOH and 6.6 mg·L-1 of H2O2,the removal efficiency of p-CNB is more than 80% after 30 minutes in this experiment.Both bicarbonate and humic acid have inhibitory effect on p-CNB removal,and the higher bicarbonate and humic aid concentration are,the stronger the inhibitory effect is.
    Synthesis of CPAM and its usage for DMP removal
    ZHENG Huaili1,ZHANG Peng1,DENG Xiaoli1,ZHU Guocheng1,YANG Chun1,FAN Wei1,ZHU Chuanjun2,YANG Zhi1
    2012, 63(1):  279-285.  doi:10.3969/j.issn.0438-1157.2012.01.039
    Abstract ( 1784 )   PDF (455KB) ( 607 )  
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    A preparation method for high molecular weight cationic polyacrylamide(CPAM) is reported in this paper.CPAM was prepared by using high purity industrial grade acrylamide with acryloyloxyethyltrimethyl ammonium chloride through aqueous copolymerization initiated by VA-O44.The initiator was added all at once and reaction temperature was increased stepwise to complete the polymerization gradually.The effects of reaction variables,such as temperature,reaction time,concentration of monomer and ratio of monomer on the molecular weight of product CPAM were investigated in detail.The optimum conditions were as follows: initial temperature 39℃,reaction time 5 h,monomer concentration 30% and monomer ratio of acrylamide(AM): acryloyloxyethyl trimethyl ammonium chloride(DAC) 2.3∶1.In addition,the maximum molecular weight of obtained product CPAM reached 10210000.The structure of product was characterized by FTIR.And the coagulation/flocculation process was carried out for treatment,of water containing dimethyl phthalate.The removal rate was compared with polymeric aluminum chloride(PAC),polymeric ferric sulfate(PFS),poly diallyl dimethyl ammonium chloride(PDMDAAC) and industry CPAM.During the coagulation/flocculation process,parameters,such as coagulant dosage,pH value,stirring time,and settling time were investigated.The results showed the organic coagulant PDMDAAC,industrial CPAM and self-made CPAM had better coagulation effects than inorganic coagulant PAC and PFS,and the self-made CPAM had the best coagulation effects,with an initial DMP concentration of 0.50 mg·L-1,the addition of a self-made CPAM dosage of 12.5 mg·L-1 and the best removal rate of DMP was 97.3%.
    Antibacterial property of polymeric quaternary ammonium salt immobilized on modified activated carbon
    ZHOU Jingru,PEI Lixia,ZHANG Lizhi
    2012, 63(1):  286-291.  doi:10.3969/j.issn.0438-1157.2012.01.040
    Abstract ( 2436 )   PDF (617KB) ( 571 )  
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    Polymeric quaternary ammonium salt was immobilized on activated carbon(AC),by oxidation of AC with concentrated nitric acid,subsequent eletrostatic assembly to produce a high-performance bactericide(P-AC)with good adsorption.The surface characteristics of AC before and after modification were analyzed by Boehm method.The composition and microstructure of P-AC were characterized by FTIR and TG.The adsorption capacity of the obtained P-AC was tested using phenol as a model compound,and the antibacterial activity against E.coli was also measured.The results show that:(1)AC is well modified by concentrated nitric acid,carboxyl and lactone groups of AC increase while the hydroxyl groups decrease;(2)Polymeric quaternary ammonium salt was immobilized on modified AC with loading of 12%(mass),P-AC has lower BET surface area and the pore volume than AC,but has the larger average pore diameter;(3)P-AC exhibits good adsorption property for phenol,which is 82.5% of adsorption capacity of AC;(4)P-AC shows excellent antibacterial property,an antibacterial efficiency for E.coli of 99% can be achieved over a period of 2 hours.And a slight decrease of 5% in antibacterial efficiency can be observed after 10 batches of regeneration-antibacterial action cycle tests.
    Thiol and thioether removal from RFCC gasoline with attapulgite clay
    WANG Qingning, ZHANG Zhengcai, XIE Zhenping, WU Yingqin, LI Lan, JIAO Linhong
    2012, 63(1):  292-300.  doi:10.3969/j.issn.0438-1157.2012.01.041
    Abstract ( 1953 )   PDF (1208KB) ( 469 )  
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    One of main pollutants in air is sulfur oxides that comes from the combustion of coal and transportation fuels.There are some regulations or rules in many countries,which set the level of sulfur content in transportation fuels,so it becomes urgent to do ultra-deep desulfurization.Hydro-desulfurization process is usually used in petroleum refining industry,in which compounds containing-sulfur are converted to H2S removed in high temperature and high hydrogen pressure.However it is difficult for removing aromatic heterocyclic sulfur.So,alterative technologies have been developed,such as adsorptive-,oxidative- and bio-desulfurization.In this paper a desulfurization agent for residue fluid catalytic cracking gasoline(RFCCG) was prepared by impregnation technique.The compounds of transition metals(Fe,Cu) were used as active component and the attapulgite,treated with nitric acid,as carrier.The sulfur content in RFCCG was analyzed by gas chromatography with atomic emission detection(GC-AED).The desulfurization agent was characterized by fourier transform infrared spectrometer(FTIR),X-ray diffraction(XRD),BET and X-ray photoelectron spectroscopy(XPS).The parameters of desulfurization process for the agent were optimized by experimental study designed by the orthogonal test.The results indicated that the best desulfurization agent obtained are 7% Fe and 6% Cu compounds on attapulgite which was acidulated and roasted at 450℃ for 5 h.The desulfurization rate was 70.02% at atmosphere pressure and room temperature,and sulfur content in RFCCG reduced from 804 μg·g-1 to 241 μg·g-1.
    Preparation,characteristics and adsorption properties of anion resin prepared from biomass
    GAO Yue,XU Xing,GAO Baoyu,YUE Qinyan
    2012, 63(1):  301-306.  doi:10.3969/j.issn.0438-1157.2012.01.042
    Abstract ( 2151 )   PDF (439KB) ( 490 )  
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    An anion exchange resin(MWS,modified wheat straw) was prepared by chemical modification of wheat straw grafting epichlorohydrin,triethylamine and diethylenetriamine to improve MWS performance,particularly for adsorption of NO-3 in water.The results showed that amine groups with positive-charge had been introduced into the structure of MWS,which resulted in improving significantly adsorption capacity for NO-3 in water.The analysis of zeta potential and surface elemental as well as FTIR and Raman spectra indicated that the adsorption mechanism of MWS for NO-3 was ion exchange.The adsorption data could be well fitted with the Langmuir model and the correlation coefficient(R2) was higher than 0.988.The results of competition adsorption indicated that the adsorption efficiency for co-present ions followed an order as SO2-4>H2PO-4>NO-3>NO-2.The maximum adsorption capacity(Qmax) of MWS for NO-3 was 52.1 mg·g-1,which could compared with that of commercial resin,and showed that there was a significant increase than that of raw WS(1.3 mg·g-1).In addition,column adsorption test showed that the breakthrough adsorption capacity for NO-3 was about 45.2 mg·g-1,and both 0.1 mol·L-1 NaCl and HCl solutions could be used as regenerating agent for the desorption of NO-3 from the MWS.
    Preparation and flame retardancy of siloxane modified epoxy resins based on acrylic acid rosin
    DENG Lianli1,2,SHEN Minmin1,YU Jing1,2,WU Kun1,CEN Xueyang1,HA Chengyong1
    2012, 63(1):  307-313.  doi:10.3969/j.issn.0438-1157.2012.01.043
    Abstract ( 2055 )   PDF (1108KB) ( 615 )  
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    Silicone modified epoxy resins is prepared via polycondensation of polymethylphenylsilicone DC-3074(PMPS) and epoxy resin from acrylic acid rosin(AR-EGDE).The chemical structure of the produced resins was determined by FTIR,13C NMR and epoxy content testing.At the same time,physical modified resin is obtained by mixture of PMPS and AR-EGDE.Mechanical properties and limiting oxygen index(LOI) value of the cured epoxy resins were studied.The results indicated that the method of modification played an important role in the properties of cured resins.The cured system of chemically modified resin had better properties.The tensile strength of the system was slightly lower than the unmodified resin AR-EGDE,at the same time its breaking elongations increased rapidly.The LOI value of the system increased from 21.6%(unmodified) and 25.3%(physically modified) to 30.2%.The thermogravimetric analysis(TGA) result showed that the thermal stabilities of the modified resins were better than those of unmodified resin.Because PMPS segment could absorb more thermal energy and dissipate thermal energy through its flexible siloxane structure,the onset decomposition temperatures(T-5%) for modified resins were higher than that of unmodified resin.The solid residue at 700℃ of the modified resins were 14.9% for chemically modified and 16.2% for physically modified,more than that of the unmodified resin.The chemical structure of char for the resin at the end of LOI test was analyzed by Fourier transform infrared spectroscopy.Based on the above results,the flame retardant mechanism was discussed.At an elevated temperature or upon burning,the silicone-containing group immigrated to the surface of material rapidly and formed a stable carbon-silicon residue.The carbon-silicon residue could act as thermal insulation which inhibited the degradation of the underlying material and improved the flame retardancy of the material.The physically modified resin could not form efficient carbon-silicon residue during burning,so its LOI value was lower than that of the chemically modified resin.
    Influence of ammonia state on particle characterization of magnesium hydroxide prepared via ammonia method
    YAO Jianping, FAN Tianbo, WANG Jian, LI Xue, LIU Yunyi
    2012, 63(1):  314-319.  doi:10.3969/j.issn.0438-1157.2012.01.044
    Abstract ( 2568 )   PDF (1207KB) ( 636 )  
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    Ammonia method is one of the main methods to prepare magnesium hydroxide,and according to the different states of ammonia into the reaction system,ammonia method includes aqua ammonia precipitation method and gaseous ammonia precipitation method.In order to study the influence of ammonia in different states on particle characterization of magnesium hydroxide,magnesium chloride was used as reaction material,magnesium hydroxide were prepared respectively with aqua ammonia and gaseous ammonia as precipitant.Scanning electron microscope(SEM),X-ray powder diffraction(XRD) and laser particle size analyzer were used to characterize the products.The results showed that crystal forms of the magnesium hydroxide products obtained by these two methods both tended to be perfect with increasing reaction temperature,and the dispersion property was also improved.Magnesium hydroxide prepared by gaseous ammonia precipitation method presented inerratic cubic pieces(hexahedron structure) when reaction temperature was higher than 75℃,the dispersion property of the particles were better than those prepared by aqua ammonia precipitation method.Aqua ammonia concentration was also a significant factor affecting the morphology of magnesium hydroxide,and the particle size and dispersion property would gradually become close to the products of gaseous ammonia precipitation method with increasing aqua ammonia concentration.This work provided valuable reference for selection and application of ammonia precipitation method to prepare magnesium hydroxide.
    DPD simulation of fiber falling in melt electrospinning
    WANG Xin,LIU Yong,YAN Hua,GUAN Changfeng,YANG Weimin
    2012, 63(1):  320-324.  doi:10.3969/j.issn.0438-1157.2012.01.045
    Abstract ( 2233 )   PDF (3459KB) ( 531 )  
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    Electrospinning has attracted much attention recently as a direct and consecutive fabrication technique for producing nano-scale to micro-scale fibers.In order to achieve deeper understanding of fiber change in the electrospinning process,this paper explores the mesoscopic simulation method of dissipative particle dynamics to create the electrospinning simulation system.The effect of viscosity on fiber falling velocity in different stages,the effect of chain length on fiber falling morphology and the effect of spring coefficient on end to end distance of polymer chains were successfully simulated.Melt-electrospinning process was theoretically studied and explored from the mesoscopic perspective.Deeper comprehension of scientific issues of this physical phenomenon was acquired.
    Application of online measurement of melt density in polymer precise injection molding
    XU Hong,WU Daming,LIU Ying,ZHANG Yajun
    2012, 63(1):  325-330.  doi:10.3969/j.issn.0438-1157.2012.01.046
    Abstract ( 1758 )   PDF (727KB) ( 395 )  
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    Based on the strong relationship between ultrasonic speed and properties of the propagation medium and the rapid response of ultrasonic speed to the medium properties,the theoretical and experimental analysis were made to conclude single valued correspondence of ultrasonic speed with density of polymer melt.Considering very short molding cycle for the injection process,an improved least square method by reducing the independent variable within the scope of 0 to 1 was proposed for the purpose of increasing computation speed.An online soft measurement model of polymer density according to single valued ultrasonic speed was established and the soft measurement model found application in precise control of injected weight of the article in the process of injection molding.Integrating the product of density of polymer melt determined by soft measurement model and cross-sectional area of the screw to stroke distance of injection,more precise control of the weight of molded article could be realized.The superiority of the weight control method based on soft measurement of melt density to the traditional volume control method was confirmed to the benefit of improving repeat weight accuracy of molded articles.