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Table of Content
05 March 2014, Volume 65 Issue 3
    CIESC Journal(HUAGONG XUEBAO)Vol.65 No.3 February 2014
    2014, 65(3):  0-0. 
    Abstract ( 314 )   PDF (2430KB) ( 362 )  
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    Review of super-spreading of fluids on solid substrates
    ZHU Junyue, DUAN Yuanyuan, WANG Xiaodong, MIN Qi
    2014, 65(3):  765-776.  doi:10.3969/j.issn.0438-1157.2014.03.001
    Abstract ( 1371 )   PDF (2300KB) ( 611 )  
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    The research progress of super-spreading of fluids on solid substrate is reviewed. The super-spreading systems are summarized, and the influence factors, inner mechanism,experimental correlation model and numerical simulation method are also presented. Several trisiloxane or ethoxylated surfactants and a few ionic surfactant solutions have super-spreading phenomenon on corresponding solid substrates, and surfactant concentration and solid surface energy have crucial influence on super-spreading. The Marangoni effect arising from the concentration difference along the vapor liquid interface is recognized as the key mechanism controlling super-spreading. And the surfactant transportation and adsorption on vapor-liquid, solid-liquid and solid-vapor interfaces have great influence on the Marangoni effect. The research fields for the future are also analyzed. With respect to experimental investigation, the experimental systems should be extended and the criteria for super-spreading should be established. The macroscopic influence factors should be taken into full account. With respect to theoretical investigation, the Marangoni effect as well as the interfacial properties alteration based on surfactant transportation and adsorption need to be fully considered, a full scale theoretical model could be established based on the theoretical achievement in Newtonian fluid. With respect to numerical simulation, accurate transportation and adsorption model should be established from molecular dynamics simulation and then introduced into the hydrodynamic model to make a precise super-spreading simulation. A possible schematic diagram of the whole spreading process on hydrophobic substrate of super-spreaders is also proposed.
    Progress of interfacial compatibilization methods of lignin/thermoplast composites
    CHEN Fuquan, ZHAO Yongqing, FENG Yanhong, QU Jinping
    2014, 65(3):  777-784.  doi:10.3969/j.issn.0438-1157.2014.03.002
    Abstract ( 1062 )   PDF (594KB) ( 521 )  
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    Lignin is mixed into thermoplast as organic particulate filler, which resolves the tough problems of resource utilization of black liquor from paper industry, growing tension of petroleum feedstock and increasing environmental pollution. The compatibility between lignin and thermoplast is directly related to application and development of lignin in the plastics industry. This paper begins with an overview of the structure and properties of lignin and performance analysis of lignin/thermoplastic composites, and then elaborates the methods and principles of interfacial compatibilization between lignin and thermoplast. The methods of compatibilization are divided into adding compatibilizer, modifying lignin and modifying thermoplastics, and the three methods are compared and analyzed. The methods of adding compatibilizer and modifying thermoplastics are more commonly used than the modifying lignin for interfacial compatibilizing of the composites. Esterified lignin has better compatibilization than alkylated lignin. Then alternate and compounded use of the compatibilizing methods for lignin-based composites are reviewed. Finally, future research directions and ideas of compatibilization in lignin/thermoplastic composites are discussed.
    Simulation of oil-vapor condensing recovery process based on several state equation models
    LI Yinglin, TAN Laizai, ZHANG Xiaosong
    2014, 65(3):  785-791.  doi:10.3969/j.issn.0438-1157.2014.03.003
    Abstract ( 892 )   PDF (567KB) ( 342 )  
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    The selection of state equation for simulation of condensing oil-gas recovery is still questionable. In this study, by establishing the phase equilibrium model and thermodynamic parameter models, simulation results of condensing oil-vapor recovery process are compared. The phase equilibrium model is composed of state equations, substance balance equation, and thermodynamic equilibrium equation, with model iteration steps. State equations include SRK, PR, TJS and ideal-gas state equation. The simulations present following results. (1) The simulation results are verified by existing test data. For TJS equation, average deviations of gas and liquid mole fractions are 4.03% and 3.54%, respectively, meeting the precision requirement. For SRK equation, at mole fractions of component higher than 5%, average deviations of CH4 and C2H6 are 2.8% and 3.5%, respectively, while at mole fractions less than 5%, average deviation of C3H8 is 18.5%, meeting the precision requirement. (2) When the oil-gas mixture is considered as ideal gas, the simulation results differ greatly from those with the real-gas state equations, such as SRK, PR or TJS equation, so for the oil-vapor mixture can not be treated as ideal gas, and SRK and TJS equations are preferred. (3) The simulation results of SRK, PR, TJS and Aspen Plus software are equivalent, while the simulation result of PR model is slightly worse. The mathematical model and simulation analysis on condensing oil-vapor recovery process provide theoretical references for future experiment.
    Characteristic of thermal conduction in hydrocarbon hydrates using molecular dynamics method
    WAN Lihua, LIANG Deqing, GUAN Jin'an
    2014, 65(3):  792-796.  doi:10.3969/j.issn.0438-1157.2014.03.004
    Abstract ( 819 )   PDF (809KB) ( 378 )  
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    Equilibrium molecular dynamics simulations and the Green-Kubo method are used to the sⅠ hydrates of methane, ethane and ethene to study their thermal conduction at temperature 263.15 K and pressure 3 MPa. Thermal conductivities and mean densities of the hydrates are obtained. Characteristics of thermal conduction in hydrates of hydrocarbon such as methane, ethane or ethene are studied for the effects of host and guest molecules and compactness and regularity of the crystal lattice on thermal conduction. The results show that thermal conduction is similar for the hydrocarbon hydrates that resembles chemically with indistinct difference in molecular weight. The thermal conduction of these hydrocarbon hydrates has similar temperature and pressure dependence and similar crystal structure correlation. The influence of water on thermal conductivity of sⅠ gas hydrates goes far beyond the effect of guest molecules on it. With higher mean molecular weight in hydrates, higher densities are more conducive to enhance the thermal conductivity. More compact crystal lattices improve thermal conductivities. With more regular lattice structures, phonon mean free paths are longer, so that the thermal conductivity of hydrate increases.
    QSRR/QSPR models of physicochemical properties of polybrominated diphenyl ethers
    JIN Hao, WANG Xinghao, YANG Fen, WANG Zunyao
    2014, 65(3):  797-804.  doi:10.3969/j.issn.0438-1157.2014.03.005
    Abstract ( 992 )   PDF (632KB) ( 342 )  
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    In order to investigate the physicochemical properties of polybrominated diphenyl ethers, a topological distance feature location index (T) was proposed based on the characteristic value of molecules vertex atoms (group) (δi) and calculated by a new method. A series of quantum chemical parameters was obtained by the Gaussian 03 program and molecular electronegativity distance vector (Mt) was obtained by the program in literature. Three quantitative structure-retention/property relationship (QSRR/QSPR) models between relational descriptors and chromatographic retention time, octanol/air distribution coefficient (lgKOA), and super cold fluid steam pressure at 298 K (lgPL) of PBDEs were set up by best subsets regression method. The correlation coefficients (R) were 0.9953, 0.9983 and 0.9982, the cumulative cross-validation coefficients (Q) were 0.9948, 0.9975 and 0.9975, and the standard deviations (SD) were 0.0222, 0.0754 and 0.0868, respectively. The result illustrates that the established models are reliable and better than those in literature.
    Effect of microchannel inlet configuration on Taylor bubble formation in microreactors
    DANG Minhui, REN Mingyue, CHEN Guangwen
    2014, 65(3):  805-812.  doi:10.3969/j.issn.0438-1157.2014.03.006
    Abstract ( 1004 )   PDF (3083KB) ( 363 )  
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    The effects of microchannel inlet configuration, gas-liquid flow ratio and two-phase mixture velocity on Taylor bubble formation were investigated via computational fluid dynamics (CFD) method, and the simulated values were in good agreement with the visualization experimental results. Compared with the volume of fluid method (VOF),the coupled level set and volume of fluid method (CLSVOF) could get a more accurate gas-liquid interface, and the bubbles obtained by the CLSVOF method were more consistent with the experimental measurements. The results of numerical simulation showed that microchannel inlet configuration and gas-liquid flow ratio had a great influence on bubble length, bubble generation frequency and bubble volume. For the same gas-liquid flow ratio and different inlet configurations, two-phase mixture velocity had different effects on bubble length.
    Chaotic recurrence analysis of two-component flow of mixed biomass particles and quartz sands in fluidized-bed
    WANG Xiaoyi, ZHONG Zhaoping, WANG Chunhua
    2014, 65(3):  813-819.  doi:10.3969/j.issn.0438-1157.2014.03.007
    Abstract ( 788 )   PDF (7873KB) ( 322 )  
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    Recurrence plot and recurrence quantification analysis were used to analyze the pressure fluctuation signal, and particle flow characteristics at different numbers of biomass, quartz sands and different gas velocities were investigated. The quartz sands with the diameter of 0.8 mm and cylinder-shaped biomass particles with both diameter and length of 10 mm were used as bed materials. In the bubbling section, the periodicity of the system decreased first and then increased with increasing proportion of biomass. In the slugging section, recurrence plots of signal had the same textural feature in the fluidized-bed before and after biomass was added. The bubbling section determinism and laminarity flow rate increased with increasing gas velocity, and significantly decreased at a low proportion of biomass, but entropy of the system decreased with increasing gas velocity. The slugging section determinism and laminarity flow rate had a small change and entropy of the system decreased with increasing gas velocity, showing opposite tendency from the one-component system.
    Stability analysis of dense phase pneumatic conveying of pulverized coal at high pressure
    HE Chunhui, SHEN Xianglin, ZHOU Haijun
    2014, 65(3):  820-828.  doi:10.3969/j.issn.0438-1157.2014.03.008
    Abstract ( 1445 )   PDF (1353KB) ( 683 )  
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    Based on a self-developed dense phase pneumatic conveying system, conveying tests of three lignite pulverized coal with different mean particle sizes using N2 as carrier gas were carried out. The Hurst exponents of pressure drop fluctuation signals in horizontal pipe and mass pulsations of material storage tank were calculated using rescaled range analysis. The standard deviations of mass pulsations were analyzed. The Hurst exponent and standard deviation were used as an indicator of conveying stability. The flow stability of conveying pipe was well characterized by Hurst exponents of pressure drop fluctuation signals (Hdp), while the discharge stability of material tank was not well characterized by Hurst exponents of mass pulsations (Hma) and standard deviation analysis was required. Conveying stability was investigated according to the ratio of superficial gas velocity to saltation velocity (K). At the left side of K=1.5, Hdp decreased with the decrease of K, the flow regime in gas-solids horizontal conveying pipe was changed and even caused a pipe blockage, the flow stability of conveying pipe became worse. Meanwhile, the standard deviation of mass pulsations increased as K decreased, the discharge stability of material tank deteriorated, and conveying stability became worse. At the right side of K=1.5, as K increased, decreasing trend of Hdp was not obvious, through combined analysis with standard deviation analysis, discharge stability became worse and might cause interruption of discharging.
    Numerical simulation on shell side fluid flow and heat transfer in heat exchanger with trefoil-baffles
    ZHU Lingyun, LANG Hongfang, ZHOU Guoyan, GUO Zhen, TAN Xianghui, YANG Jinchun, ZHU Dongsheng
    2014, 65(3):  829-835.  doi:10.3969/j.issn.0438-1157.2014.03.009
    Abstract ( 1085 )   PDF (836KB) ( 480 )  
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    Heat exchangers with trefoil-baffle are a new type heat transfer device and are widely used in nuclear power system due to their special advantages, with the fluid flowing longitudinally on the shell side. In this study, to avoid the limitation of unit duct model, a whole model for the heat exchanger with trefoil-baffles is established including inlet and outlet nozzles. Based on the RNG k-ε model, numerical simulation shell side fluid flow and heat transfer are conducted by using commercial CFD software FLUENT14.0. Characteristics of fluid flow and heat transfer performance on the shell side are analyzed. The results show that the fluid is fully developed after the first trefoil-baffle and the heat transfer coefficient and pressure drop vary periodically along the shell side. Fluid velocity increases gradually and the jet flow forms in the region near baffles. The secondary flow is also produced on two sides of baffles when the fluid flows through the trefoil-baffle. The jet flow and secondary flow can decrease the thickness of boundary layer and enhance the heat transfer.
    Application of modified impacting tee to achieve equal quality distribution of gas-liquid two-phase flow
    TIAN Jing, WU Ming, WANG Shuai, ZHANG Bingdong, WANG Dong
    2014, 65(3):  836-842.  doi:10.3969/j.issn.0438-1157.2014.03.010
    Abstract ( 827 )   PDF (556KB) ( 253 )  
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    An effective improved method, the installation of orifice plates at the branches of the impacting tee, was proposed to achieve equal quality distribution of gas-liquid two-phase flow in the impacting tee. First, this paper explains the reason why the impacting tee cannot achieve equal quality distribution through analyzing its phase distribution characteristics. Then, the distribution principle of the modified impacting tee is presented. The experiments are conducted in the air-water multiphase flow test loop. The results of the experiments show that this distribution device can improve the distribution characteristics of the gas-liquid two-phase flow apparently, and significantly reduce the deviation of the quality between the two branches. When the size of the orifice plates is appropriate, the quality between two branches can be nearly equal. At last, the factors influencing the equal quality distribution of the modified impacting tee and the equation of the best aperture ratio are presented on the basis of the theoretical model and the experimental data.
    Deformation and breakup of dispersed phase droplets in uniform electric field
    LIANG Meng, LI Qing, WANG Kuisheng, LIU Jingye, CHEN Jiaqing
    2014, 65(3):  843-848.  doi:10.3969/j.issn.0438-1157.2014.03.011
    Abstract ( 1128 )   PDF (4950KB) ( 601 )  
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    Through coupling hydrodynamics and electrostatics, a phase field method based on Cahn-Hilliard formulation was used to predict the deformation and breakup of dispersed phase droplets in a uniform electric field. The distribution of charge density, electric field strength and electric field force on the droplet surface as well as the distribution of flow field and electric field were studied from the micro-perspective. The micro-droplet deformation mechanism was established. The influence of electric field strength, droplet diameter and interfacial tension on the deformation was predicted by numerical simulation. The results showed that strong electric field intensity, large droplet diameter or small interfacial tension could cause larger degree of droplet deformation. The droplet mainly ruptured from its middle or the two ends. Rupture mainly depended on the physical properties of the continuous phase and dispersed phase. The above study would provide a theoretical basis for complex electric demulsification.
    Effects of anchor-type ducts on film condensation of HFC245fa on horizontal tube bundle
    MA Zhixian, ZHANG Jili, SUN Dexing
    2014, 65(3):  849-854.  doi:10.3969/j.issn.0438-1157.2014.03.012
    Abstract ( 732 )   PDF (1083KB) ( 265 )  
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    Tube row effect, part of the inundation effect induced by falling condensate formed on neighboring tubes above, has hindered the heat transfer of shell and tube condenser for a long time. This paper put forward a scheme to eliminate the tube row effect by anchor-type ducts and further investigated its effect on film condensation heat transfer coefficient (CHTC) of HFC245fa on the tube bundles. A 4-line-wide and 5-row-deep tube bundle consisting of smooth tubes and finned tubes, with two columns out of the four equipped with the anchor-type ducts, was built in the test section. Equivalent outside diameter and active length of all tubes in the test section were 19.05 and 500 mm, respectively. The modified Wilson plot method was used to determine the waterside convection heat transfer. The short-period-calibrate method and homogenous method were used to determine the tube row effect with high-precision. Results show that: ① tube row effect can be well controlled by the anchor-type ducts; ② adverse effect of anchor-type duct on CHTC of each tube in the bundle is negligible; ③ with the anchor-type duct, more than 20% (or 30%) of smooth tubes (or enhanced tubes with three dimension fins) can be saved for a tube bundle in a shell-tube condenser of diameter 600 mm. This paper can be used to guide the design of high efficiency shell-tube condenser.
    Characteristics of void fraction distribution of bubbly flow in inclined channels
    YAN Chaoxing, YAN Changqi, SUN Licheng, XING Dianchuan, LIU Guoqiang
    2014, 65(3):  855-861.  doi:10.3969/j.issn.0438-1157.2014.03.013
    Abstract ( 980 )   PDF (1195KB) ( 304 )  
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    Experimental investigation was carried out on the characteristics of void fraction distribution in a narrow rectangular duct (3.25 mm×43 mm) as well as a conventional circular tube (i.d.50 mm) under inclined conditions to study the influence of inclination on bubble and gas-liquid interface distribution. Air and purified water were used as the test fluids and three inclination angles of 5°, 10° and 15° were selected for experiments. Only wall peak distribution was observed in the narrow rectangular duct and no core peak was present, while for the circular tube, both were observed. Inclination had similar effect on wall peak distribution in two channels. Accordingly, with increasing inclination angle, the peak near the upper wall of the tube boosted up, whereas, the one near the lower wall weakened gradually, and even disappeared. As to core peak distribution in the circular tube, central broad peak leaned to the upper part of the tube, and its value increased as inclination angle increased. In addition, the position of wall peak in the narrow rectangular duct was closer to the channel center than that in the conventional circular tube.
    Breakdown of liquid films driven by horizontal gas flow in wave-plate channel
    ZANG Liye, TIAN Ruifeng, SUN Lanxin, XING Zhihui, TIAN Jinyun
    2014, 65(3):  862-869.  doi:10.3969/j.issn.0438-1157.2014.03.014
    Abstract ( 693 )   PDF (747KB) ( 277 )  
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    A two-dimensional boundary layer model was established to describe the lateral flow of falling films driven by horizontal gas flow in the wave-plate channel based on boundary layer theory and independence assumption. The model reduction was presented through dimensionless analysis and ideal laminar flow assumption. The theoretical model was built to predict the films lateral migration and separation under the horizontal interface shear stress based on analytical force balance. The effects of wave-plate structure, both physical properties and flow conditions of gas-liquid were considered to give a critical separation criterion of the falling films along wave-plate. The criterion was compared with experimental measurements and some published theoretical models. The present model led to significantly better agreement with the experimental results and can be used to predict the breakdown of the films more accurately. Dimensionless analysis showed that inertial centrifugal force, shear stress, viscous force and surface tension controlled the movement, deformation and breakdown of liquid films, whose instability was associated with the equilibrium of these four forces.
    Numerical simulation of thermal dispersion in porous media with large porosity
    CHEN Zhongshan, XIE Maozhao, LIU Hongsheng
    2014, 65(3):  870-878.  doi:10.3969/j.issn.0438-1157.2014.03.015
    Abstract ( 1319 )   PDF (1366KB) ( 551 )  
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    The structure of porous media with large porosity is described by a spatial periodic Weaire-Phelan model, which is built by the Surface Evolver software, and the application range of this model is determined by comparison of experimental data and simulation result for thermal effective conductivity. Based on the model, numerical computations on two specimens, with air and water as working fluids and aluminum T-6201 as solid matrix, are conducted. The effects of working parameters, such as pore size, Darcy velocity and ratio of thermal diffusion coefficient of fluid to solid, on the thermal dispersion are discussed. The simulation result shows that smaller diameter and stronger dispersion result in a more sensible dependency on thermal physical properties. In addition, the transversal component is far smaller than the longitudinal one. Empirical correlations for the longitudinal and transversal thermal dispersion are obtained in term of Peclet number.
    Influence of random porosity structure on thermal conductivity of heterogeneous porous foam
    ZHANG Xinming, WANG Jiping, GU Qinyang
    2014, 65(3):  879-883.  doi:10.3969/j.issn.0438-1157.2014.03.016
    Abstract ( 844 )   PDF (1165KB) ( 455 )  
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    Porous foam is a novel functional material, which have low density, high specific surface area and particular performance. However, porous foam is always heterogeneous, the distribution of pore structure is random. In this study, a random parameter, pore uniformity U, is proposed to study the thermal conductivity of heterogeneous porous foam and analyze the influence of pore uniformity on its effective thermal conductivity based on graphite foam. Numerical results show that the thermal conductivity of porous foam material decreases with the increase of the randomness of pore structure. A relationship between pore uniformity, porosity and thermal conductivity of heterogeneous graphite foam is proposed and compared with those in literature. The present results are in reasonable agreement with the measured data of ORNL and reflect the influence of pore structures.
    Flow boiling heat transfer characteristics in vertical upward internally ribbed tube
    WANG Weishu, XU Weihui, BI Qincheng, GU Hongfang, CHEN Tingkuan, LUO Yushan
    2014, 65(3):  884-889.  doi:10.3969/j.issn.0438-1157.2014.03.017
    Abstract ( 1330 )   PDF (666KB) ( 418 )  
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    In sub-critical pressure region, the heat transfer characteristics of water flowing in a vertical upward internally ribbed tube with diameter of φ28.6 mm×5.8 mm were experimentally investigated. The tests were performed under various conditions with pressures from 9 to 22 MPa, mass velocities from 450 to 2000 kg·m-2·s-1, and inner wall heat fluxes from 200 to 700 kW·m-2. The results show that the internally ribs of tube can effectively restrain the heat transfer from deterioration by keeping nucleate boiling. The heat transfer deterioration of dry out occurs at high steam quality in the internally ribbed tube. The increase of mass velocity can defer the sharp rise of wall temperature. The range of the sharp rise of wall temperature decreases as the mass velocity increases. With the increase of inner wall heat flux, the sharp rise of wall temperature occurs ahead at smaller steam quality, and the peak wall temperature after heat transfer deterioration increases. The steam quality corresponding to the sharp rise of wall temperature decreases at higher pressure. The heat transfer coefficient distribution curve of internally ribbed tube is in a shape of π. The top region of heat transfer coefficient is in steam-water flow boiling region. Based on the experiments, correlations of heat transfer coefficients are presented for vertical upward internally ribbed tubes.
    Evaluating heat transfer models of ground heat exchangers with multi-boreholes based on dynamic loads
    LI Yong, MAO Jinfeng, GENG Shibin, ZHANG Hua, HAN Xu
    2014, 65(3):  890-897.  doi:10.3969/j.issn.0438-1157.2014.03.018
    Abstract ( 811 )   PDF (660KB) ( 291 )  
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    The comparison of the infinite line source model, finite line source model (FLS) and moving finite line source model (MFLS) of borehole heat exchangers (BHEs) shows that the axial effects and groundwater flow have some effects on BHEs. Based on the temperature superposition principle and dynamic loads, the heat transfer models for multi-boreholes are established, combined with typical annual dynamic load model, the long-term multi-borehole heat transfer is analyzed with FLS and MFLS. The results show that the center temperature of BHEs fields calculated with FLS increases fast and heat exchanger capacity attenuation should be taken into account for a long-term running. With MFLS, reasonable optimization strategy should be used to avoid fast increase of downstream soil temperature, and stable heat transfer ability should be adopted for design to prevent inadequate capacity of late runtime. The temperature rise at typical points in BHEs filed with three-day dynamic loads shows that the operation adjustment could significantly alleviate soil temperature rise and especially reduce the heat accumulation in downstream tubes, which is very good for recovery of soil heat exchanger capacity.
    Particle size distribution measurement based on ultrasonic attenuation and phase velocity spectra
    ZHANG Wei, SU Mingxu, CAI Xiaoshu
    2014, 65(3):  898-904.  doi:10.3969/j.issn.0438-1157.2014.03.019
    Abstract ( 9 )   PDF (1574KB) ( 511 )  
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    Ultrasonic wave usually contain abundant particle size information when it passes through particulate two-phase flow. With the help of theoretical interpretation, particle size distribution (PSD) can be obtained by extracting effective attenuation and phase velocity spectra. Experiments were carried out to measure the particle size distribution of three kinds of aqueous polystyrene suspension samples with volume fraction of 10%. Attenuation and phase velocity spectra were acquired respectively by double-sample and insert-substitution methods. Furthermore, based on the ECAH model, the Twomey, ORT and an optimization method (Davidon-Fletcher-Powell algorithm) were used to inverse the particle size distribution of suspensions. The ultrasonic measurement results illustrated good consistence with those from microscope image analysis with deviation less than 15%, which indicated that measuring the particle size distribution of suspension with both ultrasonic attenuation and phase velocity spectra was feasible and reliable.
    Preparation and performance of Zn/H-ZSM-5 catalyst for catalytic amination of allyl alcohol to 3-picoline
    MA Tianqi, WEI Tianyu, PIAN Yanjie, ZHANG Yuecheng, ZHAO Jiquan
    2014, 65(3):  905-911.  doi:10.3969/j.issn.0438-1157.2014.03.020
    Abstract ( 1010 )   PDF (1759KB) ( 360 )  
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    H-ZSM-5 supported zinc catalysts were prepared by impregnation method, and their catalytic performances for amination of allyl alcohol to 3-picoline were evaluated in a fixed-bed reactor. It is found that the catalyst Zn12/H-ZSM-5(80) (H-ZSM-5 with 80 silicon/aluminum (Si/Al) ratio and zinc loading of 12%) shows the best performance among all the studied catalysts. 97.8% conversion of allyl alcohol and 37.9% selectivity toward 3-picoline are obtained on this catalyst using reaction conditions: atmospheric pressure, at 420℃, ammonia/allyl alcohol mole ratio 3:1 and gas hour space velocity 300 h-1. The characterization results, obtained by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and FT-IR of absorbed pyridine, indicate that zinc on Zn12/H-ZSM-5(80) is Zn2+, there is Lewis acid on HZSM-5. In 3-picoline formation, ZnO provides active sites of dehydrogenation reaction, and addition and cyclization reactions are mainly catalyzed by the Lewis acid.
    Preparation of levoglucosenone by catalytic pyrolysis of cellulose over solid phosphoric acid
    ZHANG Zhibo, DONG Changqing, YE Xiaoning, LU Qiang, LIU Yongqian
    2014, 65(3):  912-920.  doi:10.3969/j.issn.0438-1157.2014.03.021
    Abstract ( 1434 )   PDF (1386KB) ( 620 )  
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    Solid phosphoric acid supported on SBA-15 carrier was mechanically mixed with the cellulose, and then the mixture was subjected to fast pyrolysis to prepare levoglucosenone (LGO). Using Py-GC/MS (pyrolysis-gas chromatography/mass spectrometry) the effect of temperature and catalyst/cellulose ratio on pyrolytic products mainly LGO was examined. The results indicated that the presence of solid phosphoric acid could inhibit formation of levoglucosan (LG) and other byproducts, but promote greatly and selective formation of LGO, one of major pyrolytic products. The maximal LGO yield and relative content were obtained at the temperature of 350℃ and the catalyst/cellulose ratio of 1/1, having the relative peak area of 68.6%. Moreover, the solid phosphoric acid would also promote the dehydration of LG to form LGO.
    Preparation and structure characterization of superparamagnetic supported catalyst H3PW12O40/Fe3O4@SiO2 and its application in olefinic alkylation desulfurization
    XIONG Xiaolong, LIU Zili, XU Cuixia, QIN Zuzeng
    2014, 65(3):  921-928.  doi:10.3969/j.issn.0438-1157.2014.03.022
    Abstract ( 1133 )   PDF (948KB) ( 551 )  
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    Fe3O4@SiO2 nanocomposite was prepared via modified Stöber method and used as catalyst support. Superparamagnetic supported catalystsprepared by loading H3PW12O40 (HPW) onto Fe3O4@SiO2 support through a wet impregnation method, were used for alkylation reaction, and characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), NH3-temperature programmed desorption (TPD), scanning electron microscope (SEM), N2-adsorption and vibrating sample magnetometer (VSM). Their physicochemical characterization revealed that HPW had been immobilized and dispersed on Fe3O4@SiO2. Moreover, 40%(mass) HPW loading catalyst, been of high magnetization 30.1 emu·g-1, mesoporous structure and the surface area 303.6 m2·g-1, could be considered to be a proper catalyst for olefinic alkylation of thiophenic sulfur (OATS) and they can be easy separated by external magnetic field. In addition, their catalytic activity was also investigated in alkylation reaction of a model mixture of thiophene and 1-octene, and the conversion of thiophene was up to 85.5% after 2 h at 160℃.
    Curing mechanism and kinetics of epoxy/anhydride system modified by benzoxazine
    LIAO Jinbin, JIANG Qibin, ZENG Zhi, LI Hongyan
    2014, 65(3):  929-933.  doi:10.3969/j.issn.0438-1157.2014.03.023
    Abstract ( 1058 )   PDF (622KB) ( 339 )  
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    An epoxy/anhydride system was modified by aromatic diamine-based benzoxazine. The curing mechanism of the system was analyzed with Fourier transform infrared spectroscopy(FT-IR)and differential scanning calorimetry (DSC). The blend system exhibited two curing reactions in the curing process. Epoxy resin first cured with sufficient anhydride catalyzed by imidazole at 100℃, and cured completely at 150℃ for 2 h. Benzoxazine underwent ring-opening polymerization at 180℃. The curing kinetics of modified resin system was studied with non-isothermal DSC at different heating rates. The average activation energies of two reactions were calculated utilizing the Flynn-Wall-Ozawa method to be 65.27 kJ·mol-1 and 92.8 kJ·mol-1, respectively. Both curing reactions were found to be autocatalytic processes by the Friedman method, and the predicted curves from the autocatalytic model fitted well with those of experiments.
    Adsorption of n-paraffins on mesoporous 5A zeolites
    LIU Zhiping, ZHANG Qiangqiang, MA Jinghong, LI Ruifeng
    2014, 65(3):  934-941.  doi:10.3969/j.issn.0438-1157.2014.03.024
    Abstract ( 952 )   PDF (785KB) ( 468 )  
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    Adsorption equilibrium isotherms of n-hetpane, n-octane and n-decane on 5A zeolites with intracrystalline mesopores were studied by gravimetric technique at 293, 308 and 318 K, and were compared with that on microporous 5A zeolite. The adsorption data from the three n-paraffins on mesoporous 5A zeolites are well correlated by the Langmuir-Freundlich and Toth models. Due to the coexistence of micropores and mesopores on mesoporous 5A zeolites, the maximum adsorption capacity is higher and the energetic heterogeneity is more obvious, while the affinity to the adsorbent evaluated by Henry's constant and the heat of adsorption at zero coverage decrease in the presence of mesopores in zeolite crystals. The isosteric heat of adsorption calculated by Clausius-Clapeyron equation decreases with the increase of surface coverage of n-paraffins. The change of decane is most obviously.
    Performance of ammonia adsorption by aerobic granular sludge
    WANG Changwen, ZHAO Baihang, LI Jun, LIU Guoyang
    2014, 65(3):  942-947.  doi:10.3969/j.issn.0438-1157.2014.03.025
    Abstract ( 910 )   PDF (460KB) ( 269 )  
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    Ammonia adsorption by a adsorbent, aerobic granular sludge cultured in a lab-scale SBR, and influencing factors were studied at (25±1)℃ and in 0.1 mol·L-1 Trise-HCl buffer reaction system. Comparing with flocculent activated sludge the aerobic granular sludge exhibited higher adsorption capacity. At initial ammonia concentration of 30 mg·L-1, the adsorption capacity was 1.83 and 1.18 mg NH4+-N·(g VSS)-1 for granular sludge and flocculent sludge, respectively. It decreased with biomass concentration because of screen effect between cells. The effect of salinity (NaCl) on the ammonia adsorption was significant, i.e. it decreased with increase of salinity. The results indicated that the ammonia adsorption by granular sludge should not be neglected, more investigation would be needed.
    Separation and recovery of chromium and vanadium from reduced vanadium-chromium precipitate by calcinations-alkaline leaching
    YANG He, MAO Linqiang, XUE Xiangxin
    2014, 65(3):  948-953.  doi:10.3969/j.issn.0438-1157.2014.03.026
    Abstract ( 685 )   PDF (672KB) ( 404 )  
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    Separation and recovery of chromium and vanadium from reduced vanadium-chromium precipitate were implemented by calcination followed by alkaline leaching. The reaction process during calcination and the factors, such as temperature, time and alkaline medium, affecting leaching vanadium were investigated. Cr(Ⅲ) and V(Ⅳ) could form CrVO4, and then CrVO4 was decomposed into Cr2O3 and V2O5 during calcinations. The appropriate conditions for calcination were temperature of 950℃ and time of 1.0—3.0 h. Under the same molarity conditions, NaOH was better than Na2CO3 for leaching V2O5. Increasing NaOH concentration and time was favorable for leaching of V2O5 while temperature had little effect on leaching of V2O5. When reduced vanadium-chromium precipitate was calcined for 1.5 h at 850℃ and was treated for 1.5 h using 3 mol·L-1 NaOH, the content of Cr2O3 in the residue was more than 96%, and leaching rates of vanadium and chromium were 87.3% and less than 1%, respectively. Additionally, 97% of vanadium in the filtrate could be precipitated by acidic ammonium salt.
    Analysis of fouling resistance of PAA-g-ZrO2 composite membrane in filtrating BSA solution
    ZHOU Shouyong, ZHANG Yan, XUE Ailian, WANG Hui, LI Meisheng, ZHAO Yijiang, XING Weihong
    2014, 65(3):  954-959.  doi:10.3969/j.issn.0438-1157.2014.03.027
    Abstract ( 743 )   PDF (564KB) ( 384 )  
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    Fouling of PAA-g-ZrO2 composite membrane by BSA solution was investigated in conjunction with analysis of membrane total resistances and resistances distribution. The total resistances of the PAA-g-ZrO2 composite membrane and ZrO2 membrane increased with increasing filtration time, but the growth trend of the PAA-g-ZrO2 composite membrane total resistances was lower than that of the ZrO2 membrane. The fouling resistance of the ZrO2 membrane was Rcp (concentration polarization resistance)-dominant, while Rcp and Rm (membrane resistance) controlled the PAA-g-ZrO2 composite membrane separation process. The internal plugging resistance (Rif) of the PAA-g-ZrO2 composite membrane was just half of that of the ZrO2 membrane. The membrane resistance of PAA-g-ZrO2 composite membrane increased with increasing pH. The densely packed brush-shaped structure of the PAA chains was considered to be responsible for reducing the protein adsorption on the membrane surface. Furthermore, the PAA-g-ZrO2 composite membrane displayed high pH-sensitivity for BSA solutions, and could resist protein fouling in high pH applications.
    Adsorption characters of ammonium-nitrogen in aqueous solution by modified corn cob biochars
    ZHANG Yang, LI Zifu, ZHANG Lin, ZHAO Ruixue
    2014, 65(3):  960-966.  doi:10.3969/j.issn.0438-1157.2014.03.028
    Abstract ( 1075 )   PDF (1347KB) ( 523 )  
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    Biochars produced by pyrolysis of corn cob(600℃) which is agricultural waste, and modified with hydrochloric acid, hydrogen peroxide and nitric acid separately. Elemental analysis, BET-N2 surface area (SA), scanning electron microscopy, Boehm titration and FTIR spectra were used to characterized their physicochemical properties. Batch experiments were conducted to investigate ammonium adsorption process of corn cob biochars. The results revealed that acid modification can significantly improve biochars' specific surface area, which were 17.74, 212.89, 208.74 and 209.15 m2·g-1 for without modified and modified with HCl, HNO3 and H2O2 samples, respectively; while the amounts of acidic functional groups were 0.11, 0.95, 5.73 and 2.15 mmol·g-1, respectively. The results for fitting experimental data of adsorption process with isotherm models showed that it is better for Freundlich isotherm model than Langmuir isotherm model. Moreover, the adsorption process can be well described by pseudo-second-order kinetic model. The results obtained demonstrated that biochars modified with nitric acid have the highest adsorption capacity because of more acidic functional groups.
    Synthesis of multi-pass heat exchanger network based on pinch technology and superstructure model
    SUN Lin, ZHAO Ye, LUO Xionglin
    2014, 65(3):  967-975.  doi:10.3969/j.issn.0438-1157.2014.03.029
    Abstract ( 698 )   PDF (737KB) ( 465 )  
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    According to thermodynamic principle, synthesis of the heat exchanger network (HEN) with multi-pass was performed based on pinch technology, and a two-stage method was presented by using the mathematical programming methodology and pinch technology simultaneously. Firstly, the minimum temperature difference for the multi-pass HEN was optimized based on thermodynamic analysis, and then utility costs were calculated. At the second stage, according to the obtained optimal minimum temperature difference the pinch location was defined, and the corresponding HEN could be divided into two sub-networks: above the pinch point and under the pinch point. Then streams matches were optimized by using the superstructure model for the multi-pass HEN. Consequently, to minimize total cost, the multi-pass HEN was synthesized by balancing capital cost and operation cost. Case studies demonstrated the effectiveness and application prospect of the presented method.
    Application of piecewise derivative analysis in process synthesis of aniline and formaldehyde condensation reaction
    LI Yulong, HU Yangdong, WU Lianying
    2014, 65(3):  976-980.  doi:10.3969/j.issn.0438-1157.2014.03.030
    Abstract ( 789 )   PDF (452KB) ( 281 )  
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    Synthesis of polyamine from aniline and formaldehyde is a typical type Ⅲ reaction system, so the reaction process is complex. In view of the stage characteristics of type Ⅲ reaction system, piecewise derivative analysis was used to solve the problem of its reactor network synthesis. Differential side-stream reactor(DSR) or plug flow reactor (PFR) should be used in the first reaction stage and PFR should be used in the second reaction stage. A series of experiments with different process structures were done, and the results were compared with theoretical analysis. The results of the experiments showed that the amount of methylenedianiline (MDA) was the highest with the structure of DSR and PFR. The amount of MDA was the second highest with the structure of PFR and PFR. The experimental results were consistent with the piecewise derivative analysis results, indicating the effectiveness of piecewise derivative analysis.
    A genetic algorithm-estimation of distribution algorithm for a kind of heterogeneous parallel machine scheduling problem with multiple operations in chemical production
    LI Zuocheng, QIAN Bin, HU Rong, LUO Rongjuan, ZHANG Guilian
    2014, 65(3):  981-992.  doi:10.3969/j.issn.0438-1157.2014.03.031
    Abstract ( 921 )   PDF (607KB) ( 264 )  
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    A genetic algorithm-estimation of distribution algorithm (GA-EDA) was proposed to optimize the makespan criterion for a kind of heterogeneous parallel machine scheduling problem, i.e., the heterogeneous parallel machine scheduling problem with multiple operations and sequence-dependent setup times (HPMSP_MOSST), which widely existed in chemical production. Firstly, a probability model training mechanism based on GA was presented and used to increase the information accumulation of the probability model at the initial stage of the evolution, and then the efficiency of search was improved. Secondly, an effective hybrid strategy of GA and EDA was designed to help the algorithm achieve a reasonable balance between global exploration and local exploitation abilities. Computer simulation showed the effectiveness and robustness of the proposed GA-EDA.
    Characteristics of steam-gasification reaction of char with different coal rank in drop tube furnace
    DING Lu, ZHOU Zhijie, ZHAO Bing, HUO Wei, YU Guangsuo
    2014, 65(3):  993-1002.  doi:10.3969/j.issn.0438-1157.2014.03.032
    Abstract ( 803 )   PDF (2175KB) ( 372 )  
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    The steam-gasification reaction characteristics of coal char was studied in a drop tube furnace (DTF). The effects of various factors, such as coal type, gasification temperature and mass ratio of steam to char(steam/char ratio) on the properties of gas products and carbon conversion had been investigated. The experiment temperatures were1100, 1200, 1300 and 1400℃, steam/char ratios 0.4:1, 0.6:1 and 1:1, respectively. The results showed that, for all coal char studied, H2 content in gaseous products was the largest and CH4 content did the smallest. The char from coal with different coal ranks, change of gasification temperature and steam/char ratio had effects on gas composition and carbon conversion for DTF steam-gasification. At steam/char ratio of 0.4:1, 0.6:1 and 1:1, for Shen-fu' and Bei-su'char, CO and H2 yield increased continuously and H2/CO ratio decreased gradually when gasification temperature went up. The carbon conversion showed an increasing tendency with temperature increased. At gasification temperature higher than 1200℃, the change of carbon conversion of Shen-fu' and Bei-su'char was not bigger 5%, although steam/char ratio increased from 0.4:1 to 0.6:1. But the ratio increased from 0.6:1 to 1:1, the carbon conversion of Bei-su'char had a little decreasing, in contrast, for Shen-fu'char the increase of carbon conversion was higher than 15%.
    Economic evaluation of industrial chain extension solutions for coke oven gas to methanol and chemicals
    YI Qun, WU Yanli, FAN Yang, HU Changchun, CHU Qi, FENG Jie, LI Wenying
    2014, 65(3):  1003-1011.  doi:10.3969/j.issn.0438-1157.2014.03.033
    Abstract ( 964 )   PDF (795KB) ( 318 )  
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    Production cost of methanol from abundant and cheap coke oven gas (COG) is about 800—1000 CNY·t-1 lower than that from coal or natural gas. With expansion of international methanol production capacity and production scale, methanol market competition becomes more intense and cost advantage of coke oven gas to methanol is reduced evidently. It is significant to improve technology and extend industrial chains to use coke oven gas and obtain maximal benefits on the basis of coke oven gas to methanol production. One technical solution is combining coke oven gas with coal gasified gas (CGG) to produce methanol. CH4/CO2 reforming technology is used to convert CO2 + CH4 into H2+CO, and adjust H2/CO ratio of syngas in this scheme. With this scheme, methanol production can increase by 30%. Another option is to extend methanol industrial chain to obtain high-value-added downstream products, such as vinyl acetate, polyvinyl alcohol, and 1,4-butanediol. In this design, CH4 is separated from COG to make acetylene, which is used to synthesize methanol downstream products by methane partial oxidation technology. However, 0.07 billion m3 H2 surplus and small scale of methanol production are the disadvantage of this design. Concerning scale effect and industrial chain extension simultaneously, to make full use of the unused H2 resource, dual-gas (COG and CGG)-acetylene-methanol system is proposed based on the above scheme. In this solution, an appropriate proportion of the CGG is supplied to mix with surplus H2 to obtain syngas with H2:CO = 2:1, which is used to synthesize methanol. With the scale of 2 million ton coke per year, gross profits of the above three systems are 2.421, 1.892 and 2.874 billion CNY, respectively, and the internal rates of return for these schemes are 28.29%, 24.34% and 27.11% accordingly. The dual-gas-acetylene-methanol system is found to be the highest profitable system. Meanwhile, dual-gas-acetylene-methanol system is highly flexible; methanol and methanol downstream product production, as well as production technology can be adjusted according to market requirement, production capacity and resource distribution.
    Effects of solid material on blow-off limit in micro bluff body combustor
    WAN Jianlong, FAN Aiwu, LIU Yi, PI Boming, YAO Hong
    2014, 65(3):  1012-1017.  doi:10.3969/j.issn.0438-1157.2014.03.034
    Abstract ( 1194 )   PDF (1597KB) ( 372 )  
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    In the present paper, the effect of solid material on the blow-off limit of a micro-combustor was numerically investigated. For the three solid materials selected, i.e., quartz, stainless steel, and SiC, the corresponding blow-off limits obtained for the three combustors are 36, 25 and 21 m·s-1. The underlying mechanisms are analyzed in terms of the interactions between heat transfer, flow field and flame stabilization. It is revealed that for small thermal conductivity (i.e., quartz), less heat is conducted to upstream walls, the fresh mixture is not sufficiently preheated, and the gas volume does not expand so significantly, leading to a larger "low velocity zone" and thus a higher blow-off limit. For the other two materials with higher thermal conductivities (i.e., stainless steel and SiC), higher thermal emissivity (i.e., SiC) results in higher "total heat loss ratio" and lower blow-off limit. It can be concluded that the solid material with a relatively low thermal conductivity and emissivity is beneficial to obtain higher blow-off limit for the micro bluff body combustor.
    A new regeneration system for solar desiccant pre-treatment electrodialysis
    CHENG Qing, ZHANG Xiaosong
    2014, 65(3):  1018-1024.  doi:10.3969/j.issn.0438-1157.2014.03.035
    Abstract ( 671 )   PDF (479KB) ( 238 )  
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    The liquid desiccant air-conditioning system has attracted more and more attentions in recent years. As a renewable energy, solar thermal energy can be used to regenerate the desiccant solution in the liquid desiccant air-conditioning system. One problem in the solar thermal energy regeneration system is that solar energy depends on weather conditions, so that the solar thermal energy regeneration system cannot meet the dehumidification requirements when the air is hot and wet. In this paper, a new regeneration system for solar desiccant pre-treatment electrodialysis is proposed to improve the reliability of solar desiccant regeneration system. The performance of the new system is compared with that of traditional solar thermal regeneration system and the influential factors on the performance of the new system are examined. The results reveal that the new system will be more energy efficient.
    Cogeneration heating system based on ejector heat pumps
    XU Xiang, WANG Yuanchao, ZHANG Bo
    2014, 65(3):  1025-1032.  doi:10.3969/j.issn.0438-1157.2014.03.036
    Abstract ( 1044 )   PDF (606KB) ( 430 )  
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    There are two serious problems in the combined heat and power system: with the increase of heating area and quality, the heating is insufficient; the heavy discharge of low-grade thermal energy in the circulating cooling water wastes energy seriously. A novel system is presented based on ejector heat pumps (EDH-CHP) to solve the two problems by improving the heating capacity of the district heating system. It recycles the waste heat from circulating cooling water for district heating, and increases the heating capacity of the existing heating network by increasing the temperature difference between the water streams supplying and returning the original heating network. Compared with a traditional system, the new one has an additional ejector heat pump in the heating station, named HP1, and another ejector heat pump in the heating substation, named HP2. Thermodynamic analysis and experimental study are carried out for the two ejector heat pumps. The results show that both HP1 and HP2 can improve the performance of district heating under normal working conditions. Experimental results show that the COP of HP1 can reach 1.4—1.9 and the temperature of returning water in the original network can be decreased to 35℃ in HP2. A typical case study shows that the EDH-CHP system can improve the heating capacity of the existing heating network by 50% by adding 30% steam consumption, or improve the heating capacity of the existing heating network by 9% at the same steam consumption, or decrease the energy consumption by 6% at the same heating capacity.
    Solar-air composite heat source heat pump hot water system
    WANG Gang, QUAN Zhenhua, ZHAO Yaohua, HOU Longshu, XU Junfang, DENG Yuechao
    2014, 65(3):  1033-1039.  doi:10.3969/j.issn.0438-1157.2014.03.037
    Abstract ( 946 )   PDF (1096KB) ( 356 )  
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    In the light of low efficiency of photovoltaic power generation and the problems of air source heat pump applied in cold regions, a composite heat exchanger evaporator is developed and a new type of solar-air composite heat source heat pump hot water system is designed in this study, which is comprised of independent solar photovoltaic-thermal collector based on flat plate micro heat pipe and air source heat pump. The performance of heat pump hot water system is evaluated experimentally under different operating conditions, including water temperature of the tank, heating time of hot water, suction and discharge pressure, consumption of compressor power and heat pump coefficient of performance (COP), etc. Experimental results show that at ambient temperature of 5℃, 10℃ and 15℃, with 73 L hot water heated by heat pump and water temperature in the tank ranged from 15℃ to 50℃, the running time of composite heat source operation is shorter than that of separate air heat source operation, decreased by 5.14%, 10.29% and 11.38%, respectively. COPs are increased by 5.99%, 9.28% and 11.96%, respectively.
    Influence of nitrogen/phosphate deficiency on sludge settleability and filamentous growth
    YANG Xiong, PENG Yongzhen, GUO Jianhua, TANG Xiaoxue, SONG Jichen, WANG Shuying
    2014, 65(3):  1040-1048.  doi:10.3969/j.issn.0438-1157.2014.03.038
    Abstract ( 1017 )   PDF (6620KB) ( 521 )  
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    The influence of nitrogen (N), phosphate (P) and N&P deficiency on sludge settleability and filamentous growth was investigated in four sequencing batch reactors. The results showed that P deficiency in influent would cause decrease of polyphosphate-accumulating organisms (PAOs) and inhibit the storage capability of floc-formers. Moreover, the proportion of protein in extracellular polymer substances (EPS) decreased and sludge volume index (SVI) of 200—250 ml·g-1 was observed. N deficiency in influent had less impact on the growth of PAOs and the storage capability of floc-formers. Protein in EPS was significantly improved, and SVI of less than 100 ml·g-1 was observed under this condition. The short-term deficiency of N&P in influent would cause deterioration of sludge settleability, but no further deterioration was observed after long-term domestication. No excessive growth of filaments but large numbers of spherical floc-formers existed in the N&P deficiency system, resulting in SVI of around 120 ml·g-1. The dominant filaments for N, P and N&P deficiency were N. limicola Ⅱ, Type 0092 and N. limicola I, respectively. All of these dominant filaments had limited effect on sludge settleability.
    Optimization on combined UV/chlorine process for removal of ammonia in drinking water
    ZHANG Xinran, LI Weiguang, GONG Xujin, FAN Wenbiao, REN Pengfei
    2014, 65(3):  1049-1055.  doi:10.3969/j.issn.0438-1157.2014.03.039
    Abstract ( 900 )   PDF (2034KB) ( 451 )  
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    The combined UV/chlorine process, as a photochemistry process, was investigated to improve the removal efficiency of ammonia in drinking water. Based on a central composite design, the effects of Cl/N mass ratio, UV radiation time and pH value and their combination on the ammonia removal rate were evaluated. Based on a mathematical model established between them, and these technical parameters for the combined UV/chlorine process was optimized. The results showed that all of the three factors had significant impacts on ammonia removal and the combined influence of Cl/N mass ratio and UV radiation time was also outstanding. Furthermore, the prediction of a second-order regression model (R2=0.992) derived by response surface methodology was satisfactory. The conditions obtained by optimization to meet the standard of ammonia concentration in drinking water (0.5 mg·L-1) were: Cl/N mass ratio 4.00,UV radiation time 6.00 min and pH value 7.5. The experimental value agreed with the predicted value with only 0.64% deviation. Finally, these results illustrated that combined UV/chlorine process was an effectively alternative method for ammonia-containing water treatments, with several advantages of low chemical consumption, high efficiency and easy operation.
    NO conversion in C3H6/NO/N2 mixture by non-thermal plasma and emission spectrography analysis
    LI Xiaohua, WEI Xing, CAI Yixi, SHI Yunxi, JIANG Fei, DONG Miao
    2014, 65(3):  1056-1061.  doi:10.3969/j.issn.0438-1157.2014.03.040
    Abstract ( 563 )   PDF (1419KB) ( 228 )  
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    The low temperature plasma i.e. non-thermal plasma (NTP) produced by dielectric barrier discharge was employed to decompose NOx in C3H6/NO/N2 mixture. How to make this process higher conversion efficiency with lower energy cost is a topic of the present study. In order to study the effect of hydrocarbon on NO conversion in diesel exhaust, in experimental study C3H6/NO/N2 mixture was treated by NTP and an optical emission spectroscopy diagnosis technology adopted to obtain the information about radicals and excimer in the discharge space produced by NTP. The results indicate that with increase of discharge power, NO conversion efficiency increases sharply first and then slows down to a constant value, and NO2 concentration gradually decreases while N2O concentration grows up first and then goes down. NO in the mixture is mainly reduced to N2. At the same discharge power, with increase of C3H6 initial concentration NOx conversion efficiency and N2O concentration increases while NO2 concentration decreases. The addition of C3H6 can make the spectral intensity of NO-γ band and N2 second positive band decreases, while do CN radical to stimulate the transition spectral line, which can affect NO conversion mechanism, and so the formation of yellow polymer.
    Effect of Cu2+ on biofilm and extracellular polymeric substance
    HU Xuewei, LI Shu, RONG Ye, JIANG Meng, ZHANG Yan, LI Yuan
    2014, 65(3):  1062-1067.  doi:10.3969/j.issn.0438-1157.2014.03.041
    Abstract ( 934 )   PDF (634KB) ( 337 )  
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    Through adding different concentration of Cu2+ in the biofilm reactor, the relationship between extracellular polymeric substance(EPS) secreted by biofilm and efficiency of copper removal by biofilm was studied. Biofilm tolerance of Cu2+ was better than activated sludge, but a high concentration of Cu2+ rapidly poisoned the biofilm. When Cu2+ < 2 mg·L-1, Cu2+ inhibited biofilm secretion of EPS. Concentration of 2 mg·L-1 < Cu2+ < 5 mg·L-1, Cu2+ would increase the amount of EPS, while Cu2+ > 5 mg·L-1, the biofilm system displayed serious instability. Comparing proteins/polysaccharide (PN/PS) value showed that the biofilm suffered inhibition by Cu2+. The biofilm would inhibit more extracellular polysaccharide secretion, and the biofilm resistance of Cu2+ indicated that the biofilm would secrete more extracellular protein. The amount of EPS had a good correlation with the enrichment ratio of Cu2+.
    Dewatering performance of sludge modified by inorganic conditioner combined with surfactant
    HONG Chen, XING Yi, WANG Zhiqiang, ZHANG Kun, SI Yanxiao
    2014, 65(3):  1068-1075.  doi:10.3969/j.issn.0438-1157.2014.03.042
    Abstract ( 1005 )   PDF (1770KB) ( 350 )  
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    Dewatering performance of sludge modified by CaO and PAFC combined with surfactant is investigated in this study. Water content of dewatered sludge and specific resistance of filtration (SRF) are used to evaluate the sludge dewaterability, and the change of sludge dewaterability is explained by measuring variation of extracellular polymeric substance (EPS) content and Zeta potential in the conditioning process. The results show that adding surfactant can change EPS content in the filtrate, and reduce SRF and water content of dewatered sludge, and improve dewatering performance of sludge. The effect of CaO and PAFC combined with surfactant is better than individual surfactant. The addition of CaO and PAFC can both improve sludge dewaterability and contribute to reduce the addition of surfactant. The content of EPS and its components in sludge filtrate has a high correlation with the water content of dewatered sludge and SRF, and an important effect on the detwatering performance of sludge. The optimal conditions determined by experiment is that the addition amount of CaO, PAFC, surfactant is 66.67 mg·g-1, 33.33 mg·g-1, 56.25 mg·g-1, and the water content in dewatered sludge and SRF are 69.41%、0.294×1013 m·kg-1, respectively.
    Removal of cadmium in micropollution source water
    YANG Wei, LIU Canbo, YU Min, TIAN Jiayu, LI Guibai, REN Nanqi
    2014, 65(3):  1076-1083.  doi:10.3969/j.issn.0438-1157.2014.03.043
    Abstract ( 811 )   PDF (833KB) ( 457 )  
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    Source water in China contains in general pollutants of trace heavy metals. In this paper it is suggested that use of hydrous manganese dioxide enhance removal of cadmium in source water without changing the conventional treatment technique. Hydrous manganese dioxide prepared with thiosulfate and potassium permanganate by oxidation-reduction reaction was used as a new type of purifying agent. The parameters such as pH,turbidity and humic acid, which affect its purifying efficiency, were also studied. The properties of new purifying agent, such as morphology, surface composition and structure are characterized by X-ray diffraction(XRD),X-ray photoelectron spectroscopy (XPS) and transmission electron microscope (TEM) to establish links between them and coagulation phenomenon, and the characteristics of flocculation process are monitored by transmitted light fluctuation technique in order to reveal possible mechanism of cadmium removal by hydrous manganese dioxide. The results show that hydrous manganese dioxide is a kind of colloid with large specific surface, which exhibits strong adsorption characteristic thus excellent removal efficiency for dissolved and adsorbed cadmium. The mechanism of cadmium removal by hydrous manganese dioxide is probably that it is a combination result of specific adsorption, electrostatic-adsorption and entrapping-settling. So, it should be concluded that hydrous manganese dioxide can remove cadmium ions effectively from source water and can make effluent meet the national criteria for drinking water.
    Influence of conditioners for sludge deep dewatering on emission of sulfur-containing gases during sludge drying process
    LIU Peng, LIU Huan, ZHANG Qiang, LUO Guangqian, YAO Hong
    2014, 65(3):  1084-1092.  doi:10.3969/j.issn.0438-1157.2014.03.044
    Abstract ( 858 )   PDF (758KB) ( 346 )  
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    To improve sludge dewaterability the different kinds of deep dewatered sludge were prepared by using five kinds of composite conditioners. The influence of the conditioners on the emission characteristics of sulfur-containing gases during the sludge drying process was investigated via detection of water content in dewatered sludge, and of types and amount of sulfur-containing gases released at various drying temperatures (100℃, 200℃) and various residence time (30 min, 60 min). The results showed that the water content in sludge can be effectively reduced with increase of temperature and prolong of time. The major sulfur-containing gases released during raw sludge drying process were H2S and SO2, accounted for 82.4% of the total emission gas. The amount of SO2 released using conditioner FeCl3+CaO and H2SO4+FeSO4+H2O2+CaO were only 40.3% and 40.6% of the raw sludge, respectively, and no H2S was detected. While for conditioner H2SO4+FeSO4+H2O2+CaO the total amount of sulfur-containing gases released were 75.0% and 45.6% of the raw sludge at 100℃ and 200℃, respectively. So, these composite conditioners could efficiently enhance sludge dewaterability while maximally inhibit the emission of sulfur-containing gases.
    Simulation and experiments of removal process of gaseous KCl by ammonium dihydrogen phosphate
    HAN Kuihua, QI Jianhui, LI Hui, LU Chunmei
    2014, 65(3):  1093-1098.  doi:10.3969/j.issn.0438-1157.2014.03.045
    Abstract ( 931 )   PDF (710KB) ( 340 )  
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    Reduction of gaseous KCl producing in biomass combustion can help eliminate corrosion and ash deposition on the heating surface. Reaction characteristics of gaseous KCl and ammonium dihydrogen phosphate (ADP) are studied by using chemical thermal equilibrium analysis,including the effect of temperature and stoichiometric ratio. The simulation results show that gaseous KCl can be effectively transformed into K2HPO4 in a temperature range of 700—950℃. The reaction products obtained in the experiment using drop tube furnace system are analyzed by X-ray diffraction to examine the effects of mole ratio of P/K (α), residence time and temperature on KCl removal by ADP. The experimental results show that prolonging reaction time and increasing P/K mole ratio can promote conversion of gaseous KCl. At the experimental conditions: the temperature range of 700—1000℃, mole ratio of P/K of 1, residence time of 3 s, there is no KCl in the products (not detected by XRD). That means that KCl has be effectively transformed into dipotassium hydrogen phosphate (K2HPO4), potassium dihydrogen phosphate (KH2PO4), potassium metaphosphate[(KPO3)n], potassium pyrophosphate (K4P2O7), potassium ammonium phosphate, potassium-ammonium dihydrogen phosphate etc. These results will be helpful for further study removing gaseous alkali metal ions by ammonium dihydrogen phosphate.
    Turbulent flow cycle synthesis and characterization of super-fine lithium phosphate
    HU Yi, AI Changchun, LIU Yang, WU Yuanxin
    2014, 65(3):  1099-1103.  doi:10.3969/j.issn.0438-1157.2014.03.046
    Abstract ( 621 )   PDF (906KB) ( 337 )  
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    A new technology is proposed for the preparation of lithium phosphate by the co-precipitation method in a turbulent flow cycle equipment. The reaction conditions of lithium hydroxide and phosphoric acid in turbulent flow circulation kettle for the preparation of super-fine lithium phosphate were investigated. X-Ray powder diffraction (XRD), laser granularity instrument, scanning electron microscopy (SEM), specific surface and porosity analyzer and thermal analyzer were used to characterize the crystal structure, particle size distribution, morphology, specific surface area and thermal stability of the products. The lithium phosphate prepared by this method had good thermal stability, a narrow particle size distribution of D50=3.25 mm, and a specific BET surface of 13.38 m2·g-1. As a uniformly dispersed super-fine powder material, the lithium phosphate is expected to be a highly active raw material of cathode materials for lithium ion battery or an additive for lithium ion battery electrolyte.
    Polymerization behavior of silicic acid with coexisting magnesium and aluminum ions
    SHEN Xingmei, LI Liaosha, WU Xingrong, WANG Ping, LUO Tao
    2014, 65(3):  1104-1110.  doi:10.3969/j.issn.0438-1157.2014.03.047
    Abstract ( 977 )   PDF (620KB) ( 335 )  
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    Gel time, polymerization rate of monosilicic acid, and thermal performance of gel of silicic acid system with coexisting Mg2+ and Al3+ ions were investigated. At pH<4, gel time of silicic acid system decreased with the increase of coexisting concentration of Mg2+ and Al3+ ions, and Al3+ ions played an important role in the coagulation process. Polymerization reaction rate constant of monosilicic acid, for silicic acid system with coexisting Mg2+ and Al3+ ions, was higher than that for silicic acid without metallic ions, and average rate constant for MA0.1+0.1 system was k0=7.28×10-4, k1=5.62×10-4. Crystallization temperature and crystal transformation temperature of silicic acid system with coexisting Mg2+ and Al3+ ions were lower than those of silicic acid without metallic ions, and chemical formula of hydrated silicon dioxide for MA0.1+0.1 system calculated by TG curve was SiO2·0.556 H2O.
    Preparation of cellulose graft poly(butyl methacrylate) copolymers by homogeneous ATRP
    Halidan Maimaiti, Kalbinur Arken, Minawar Wumaier
    2014, 65(3):  1111-1117.  doi:10.3969/j.issn.0438-1157.2014.03.048
    Abstract ( 763 )   PDF (3672KB) ( 349 )  
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    Cellulose graft poly(butyl methacrylate) copolymers (Cellulose-g-PBMA) were prepared by homogeneous atom transfer radical polymerization (ATRP) process. Cellulose chloroacetate(Cellulose-ClAc), as macroinitiator, was synthesized first by direct acylation of cotton pulp cellulose with chloroacetyl chloride (ClC2OCl) in cellulose/LiCl/DMAc solution. Thereafter, Cellulose-ClAc was used for the ATRP of BMA (butyl methacrylate) mediated by the FeCl2/four-dimethyl aminopyridine (DMAP) catalytic system. Acylation reaction and grafting polymerization conditions, such as reaction time, reaction temperature and ratio of reactants were investigated. The hydrophobicity of Cellulose-g-PBMA copolymer was studied with contact angle measurements. Cellulose-ClAc and Cellulose-g-PBMA were characterized by means of FTIR,NMR,SEM,TEM, AFM. Gel permeation chromatography (GPC) was used to analyze the characteristics of the activity of polymerization.
    Preparation of composite nano-colorants using mini-emulsion/solvent evaporation technique
    ZHAO Xiao, LIU Jiawei, DAI Hongjun, CHEN Yongjun
    2014, 65(3):  1118-1125.  doi:10.3969/j.issn.0438-1157.2014.03.049
    Abstract ( 1060 )   PDF (1031KB) ( 413 )  
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    In the present study, the combined mini-emulsion and solvent evaporation (MESE) method was used to prepare solvent dyes/poly (methyl methacrylate) (PMMA) composite nano-colorants. Using dynamic light scattering tests, the effects of the formulation variables, including concentration of surfactant and polymer, dye loading and ultrasonication time, on the size and size distribution of the prepared nanoparticles were examined. Transmission electron microscopy (TEM), XPS and elemental analysis results indicated distinct core-shell structure of SOB/PMMA and SOY/PMMA composite colorant latexes, which proved that dyes were successfully encapsulated in the PMMA matrix using the MESE method. The dynamic migration of encapsulated solvent dyes in water and oil phase was analyzed by UV-visible spectrophotometry, which confirmed the encapsulation of the hydrophobic dyes in PMMA matrix. The resulting composite colorant could be dispersed in water. It also exhibited high light fastness, storage stability and water-fastness.
    Influence of double comb-shaped copolymer on dispersion stability of imidacloprid suspension
    HAO Han, FENG Jianguo, MA Chao, CHEN Baoying, WU Xuemin
    2014, 65(3):  1126-1134.  doi:10.3969/j.issn.0438-1157.2014.03.050
    Abstract ( 870 )   PDF (3462KB) ( 220 )  
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    In this paper, the influence of a double comb-shaped copolymer (AgrilanTM 752) on dispersion stability of imidacloprid suspension was studied with FTIR, SEM, XPS, zeta potential and particle size tests. AgrilanTM 752, which contained carboxyl groups, ester groups and poly-oxyethylene chain, combined with imidacloprid by hydrogen bond, van der Waals force and hydrophobic interaction, and dispersed imidacloprid particles in suspensions effectively. The experimental data indicated that thickness of AgrilanTM 752 adsorbed layers, zeta potential and dispersion stability of suspension reached maximum values when its content was 3%(mass), i.e., the optimum AgrilanTM 752 content under this experimental conditions was 3%(mass). Thickness of AgrilanTM 752 adsorbed layers decreased at initial pH > 6, zeta potential had a maximum value at initial pH = 10. On the other hand, dispersion stability was good at initial pH from 2 to 10, and became worse with increasing initial pH value. Moreover, experimental results suggested that electrolyte ions, such as Na+, Mg2+ and Ca2+ reduced thickness of AgrilanTM 752 adsorbed layers and zeta potential, and decreased the dispersion stability of imidacloprid suspension. Moreover, the ability of decreasing dispersion stability of imidacloprid suspension was Ca2+ > Mg2+ > Na+ at the same concentration.
    Developing process of thermal runaway for ammonium nitrate emulsion under continuous heating
    XU Sen, CHEN Xiang, DUAN Ruikun, LIU Dabin, PAN Feng
    2014, 65(3):  1135-1141.  doi:10.3969/j.issn.0438-1157.2014.03.051
    Abstract ( 996 )   PDF (4581KB) ( 374 )  
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    To study the thermal runaway of emulsion matrix under continuous heating in a fire, TG and ARC were employed to detect its thermal decomposition characteristics, and modified vented pipe test(MVPT) recommended by UN for the transport of dangerous goods did to measure the temperature evolution of sample. The TG and ARC test results show that the higher water content of emulsion matrix, the easier its demulsification, and the lower heat released by reaction is. In the MVPT test, sample temperature rises slowly between 100—146℃, and above 146℃ raise of temperature speeds up quickly, indicating appearance of obvious exothermic reaction process. When the temperature is up to 270℃, emulsion matrix takes place thermal runaway reaction (explosion). So the control of emulsion matrix temperature is very important for its transportation and storage safety.