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Table of Content
05 February 2016, Volume 67 Issue 2
    CIESC February(HUAGONG XUEBAO) Vol.67 No.2 February 2016
    2016, 67(2):  0-0. 
    Abstract ( 31 )   PDF (1604KB) ( 226 )  
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    Research progress in microfluidic preparation of chitosan functional materials
    ZHAO Hong, XU Xiaomin, XU Jianhong, WANG Tao, LUO Guangsheng
    2016, 67(2):  373-378.  doi:10.11949/j.issn.0438-1157.20150814
    Abstract ( 138 )   PDF (2793KB) ( 344 )  
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    Much attention has been paid to chitosan functional materials due to their outstanding advantages in drug controlled release, water treatment, catalysis and so on. Recently, microfluidic technology has been developed as the novel and reliable approach for the preparation of chitosan functional materials with controllable structure and size. This paper reviews the preparation and application progress of chitosan functional materials using microfluidic technology in the past decade.

    Progress in study on phase equilibria of salt-water systems
    ZHANG Jie, SHI Xuewei, ZHAO Shuangliang, SONG Xingfu, YU Jianguo
    2016, 67(2):  379-389.  doi:10.11949/j.issn.0438-1157.20151172
    Abstract ( 144 )   PDF (1335KB) ( 737 )  
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    The phase equilibria and phase diagrams of salt-water systems constitute the theoretical basis for chemical industry of inorganic salts. The fundamental studies on the phase equilibrium can provide firm support for the comprehensive development and utilization of salt lake salt resources. In this paper, the recent domestic and international research advances and methods on phase equilibria of slat-water systems from both experimental and theoretical perspectives are summarized. In particular, the experimental methods on the determination of phase diagrams for stable and metastable phase equilibrium systems as well as the factors which cause the change of phase interval and solid crystal type are presented. In addition, based on the up-to-date theoretical methods including thermodynamic models, statistical mechanics theories and computer simulations, the outline of their principles, current situations and possible extensions toward the investigation of stable and metastable phase equilibrium systems are introduced. Finally, the research hotspots in this domain are discussed along with the expectations on the future development.

    Research progress on stereocomplex crystallization of poly(lactic acid) enantiomeric blends
    YU Chengtao, HAN Lili, BAO Jianna, XIE Qing, SHAN Guorong, BAO Yongzhong, PAN Pengju
    2016, 67(2):  390-396.  doi:10.11949/j.issn.0438-1157.20150695
    Abstract ( 170 )   PDF (1397KB) ( 677 )  
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    Poly(L-lactic acid) (PLLA) and poly(D-lactic acid) (PDLA) can form stereocomplex (sc) crystallites in their racemic blends. Compared to the homocrystalline poly(lactic acid) (PLA), sc-type PLA has much better heat and chemical resistances. Therefore, sc crystallization of PLA has been an effective method to improve its physical properties. However, the formations of homo and sc crystallites are competing in the crystallization of PLLA/PDLA racemic blends. A critical issue to prepare the heat-resistant sc-type PLA is to understand the formation conditions and mechanism of sc crystallization, and further to control and promote the extent of sc crystallization. Sc crystallization is affected by a variety of factors such as the chemical structure of polymer component, crystallization and processing conditions in PLLA/PDLA racemic blends, and their influential mechanisms are very complicated. According to the various factors influencing sc crystallization, this paper will review the research progress of sc crystallization behavior and preparation of sc materials for PLLA/PDLA blends in recent years from the aspects of polymer molecular weight, stereoregularity, blend ratio, polymer topology, crystallization method and condition, and addition of additive or other components. It is expected that this review can provide a theoretical guideline for the preparation of heat-resistant biobased PLA materials.

    Progress in analysis of structure and properties of hiPP
    DA Wenzhong, TU Yuxia, XU Hongbin, MEI Li, YAO Zhen, CAO Kun
    2016, 67(2):  397-403.  doi:10.11949/j.issn.0438-1157.20151269
    Abstract ( 122 )   PDF (3746KB) ( 353 )  
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    The high impact polypropylene (hiPP) with excellent impact resistance has become a representative product of PP in industry. Study on the relationship between structure and property is always the one of the focuses in this field. The latest research progress of structure-property correlation in recent years is reviewed. Based on the analysis on morphology, the dispersed phase distribution to achieve high impact resistance has been presented. More generally at microscopic structure, the compositions of hiPP are classified as ethylene-propylene rubber, ethylene-propylene segmented copolymer, ethylene-propylene block copolymer and isotactic polypropylene, and their respective role has been described as well as effect factors.

    Progress in membrane technology for CH4-N2 separation
    LI Wen, WANG Zhi, LI Panyuan, XU Jiayou, LI Nan, WANG Jixiao
    2016, 67(2):  404-415.  doi:10.11949/j.issn.0438-1157.20151222
    Abstract ( 188 )   PDF (795KB) ( 626 )  
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    Natural gas as an efficient and clean fossil fuel plays an important role in the transformation of energy structure in China. Some conventional and unconventional natural gases contain excessive nitrogen, which could not meet the pipeline specification [nitrogen content < 4%(vol)] and decrease the heat value of natural gas. Therefore, nitrogen removal from natural gas is essential to achieve the efficient utilization of fossil fuel. Compared with traditional separation technologies such as cryogenic distillation and adsorption, the membrane-based gas separation technology possesses distinct advantages of operational flexibility, low investment and low energy consumption, exhibiting great potential in energy and environmental fields. The gas transport mechanisms suitable for CH4-N2 separation are introduced. Moreover, the developments of membrane materials and corresponding membranes for CH4-N2 separation are reviewed from CH4-selective and N2-selective membranes. Furthermore, the feasibility analysis of a two-stage membrane process with CH4-selective or N2-selective membrane is compared in different cases (nitrogen removal from conventional natural gas, shale gas and coalbed gas). Finally, prospects on membrane technology for CH4-N2 separation are presented.

    Poly(ionic liquid)s and their applications in natural product separation
    LU Yangyang, WANG Wenjun, LI Bogeng
    2016, 67(2):  416-424.  doi:10.11949/j.issn.0438-1157.20151258
    Abstract ( 178 )   PDF (562KB) ( 314 )  
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    Development of natural products relies heavily on advanced separation technologies for extraction from abundant biomass raw material sources. A novel approach for isolating natural products and their precursors is the use of the poly(ionic liquid). Poly(ionic liquid) extractants provide the polarity, designability and selectivity of ionic liquids while being less toxic and more easily recoverable. In this review, synthetic methods of polycations, polyanions and polyzwitterions are summarized. The latest progress in the use of poly(ionic liquid)-mediated solid phase extraction, solid phase microextraction, molecular imprinted solid phase extraction, liquid-liquid extraction and capillary electrophoresis technologies to separate natural products such as flavonoids, alkaloids, phenols and proteins are reviewed. This will include a description of the proposed separation mechanism and the features of this approach including the reported efficiencies, stability, and recoverability of poly(ionic liquid)s. The specific focus will be on the use of smart polymeric materials for separation of natural products. Moreover, the designing and synthetic tailoring of new species to address current challenges and expand the applicability of poly(ionic liquid)-mediated technologies for separating natural products will be introduced.

    Functionalized ionic liquids based on [EMIM][OAC] for vapor-liquid phase equilibrium of acetonitrile and water by COSMO-RS method
    LI Tingting, YANG Qing, PENG Changjun, LIU Honglai
    2016, 67(2):  425-434.  doi:10.11949/j.issn.0438-1157.20151535
    Abstract ( 83 )   PDF (2656KB) ( 229 )  
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    Based on 1-ethyl-3-methylimidazolium acetate ([EMIM][OAC]), ionic liquids composed by 15 cations and 21 anions were designed by modifying [OAC] and [EMIM] with different groups, including amine (-NH2), hydroxy (-OH), nitrile (-CN), halogen (Br, F) and so on. The effect of the designed ionic liquids on the vapor-liquid phase equilibrium of acetonitrile and water mixtures was predicted by COSMOthermX based on COSMO-RS model. The influence of group type and IL structure on relative volatility of acetonitrile was also investigated. The results showed that the ILs carrying -NH2 in cation or carrying -OH in anion can promote the separation of acetonitrile from water and the separation effect becomes more obvious with increasing number of-NH2 group. The ionic liquids composed by 2 cations (1-(2-aminoethyl)-3-methylimidazolium, 2,2,2-triaminoethyl-3-methylimidazolium) and 3 anions (hydroxyacetic acid, 2-hydroxypropanoic acid, 2-hydro-3-aminopropanoic acid) had better performance in separation water from acetonitrile than [EMIM][OAC].

    Thermodynamic modeling with new UNIFAC groups for solubility of nylon66-salt in water system
    GU Xueping, TIAN Lulu, FENG Lianfang, ZHANG Cailiang
    2016, 67(2):  435-441.  doi:10.11949/j.issn.0438-1157.20151235
    Abstract ( 118 )   PDF (502KB) ( 418 )  
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    Modeling of PA66 polymerization process requires accurate solubility computation of nylon66-salt in water system. The UNIFAC activity coefficient method with new groups was applied to predict the solubility. The new groups were -CH2COO-·+H3NCH2- and -CH2COOH, which characterized the component's special structure. The pure parameters of new UNIFAC groups and interaction parameters between new groups were obtained by regression with melting point and molar fusion enthalpy of PA66-salt as well as the solubility data of PA66-salt in water obtained by experiments. The UNIFAC model with new groups was used to simulate the solubility of PA66-salt in aqueous solution, giving a relative error of 2.1% from the experimental data. The model was further employed to simulate the concentration of PA66-salt under the industrial conditions (120℃) and gave a relative error as low as 5%, compared with 20% from the UNIFAC model with default groups in Aspen.

    Determination and model prediction of solubilities of CO2 in heavy oil under high pressure
    WANG Wei, GAO Qiang, GUI Xia, YUN Zhi
    2016, 67(2):  442-447.  doi:10.11949/j.issn.0438-1157.20151209
    Abstract ( 89 )   PDF (505KB) ( 154 )  
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    In this work, the heavy oil from some oilfield in East China was investigated. The binary vapor-liquid equilibrium data of CO2 in heavy oil was determined at 363.15, 368.15, and 373.15 K in the pressure range of 2-22 MPa by a static high pressure apparatus. The heavy oil can be regarded as one pure compound and the critical parameters of the heavy oil were calculated with group contribution method. Then the regression analysis of binary interactive parameters of supercritical carbon dioxide and heavy oil system with Peng-Robinson equation of state (P-R EOS) and the modified Patel-Teja equation of state (P-T EOS) was used to estimate the vapor-liquid equilibrium data under the same condition. It was found that the modified P-T EOS can predict the solubility data better than the P-R EOS. Thus the modified P-T EOS was more suitable for description of gas-liquid equilibrium of CO2 in heavy oil at high temperature and pressure.

    Mixing time and flow characteristic in square pump-mix mixer under different scale-up criteria
    TANG Qiao, YE Sishi, WANG Yundong
    2016, 67(2):  448-457.  doi:10.11949/j.issn.0438-1157.20151143
    Abstract ( 78 )   PDF (6772KB) ( 146 )  
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    The scale-up of the industrial mixer is always based on operation experience, and lacks theoretical basis. In this paper, effects of scale-up criteria on the mixing time and flow characteristic in the intermittent pump-mixer with single-phase has been studied. Three-dimensional time-dependent mixing prediction has been carried out using multi reference frames (MRF) method and standard k-ε model embodied by computational fluid dynamics (CFD) package FLUENT6.3. The results indicated that the calculated mixing time was depended on detecting location, but the dependency became weaker by increasing the impeller speed. The power number was obtained at different Reynolds number, and it tended to be a constant as 1.3 under the condition of sufficient turbulence. Geometric similarity ensured the axial flow characteristics in the mixer. The criterion of equal impeller tip speed and equal Reynolds number demanded a longer mixing time and obtained a lower suction pressure head than the benchmark mixer. The criterion of equal circulation time and geometrical similarity could obtain the same mixing time as the benchmark and high suction pressure head, but the power consumption per unit volume sharply increased to 24 times as the benchmark. The criterion of equal power consumption per unit volume and geometrical similarity could obtain a better balance of all the parameters considered, and was considered to be the best one compared with other three criteria.

    Physical properties measurements and CFD simulations in settler of different P507-kerosene systems
    YE Sishi, TANG Qiao, QIAO Junshuai, WANG Yundong
    2016, 67(2):  458-468.  doi:10.11949/j.issn.0438-1157.20151142
    Abstract ( 86 )   PDF (1559KB) ( 173 )  
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    Interfacial tensions play an important role on settling in rare earth element separation process. The interfacial tensions of binary liquid-liquid systems (P507-kerosene/water) and (P507-kerosene/hydrochloric acid which contain rare earths) were measured by the pendant drop method. Viscosity of P507-kerosene with different proportions was obtained by rotational viscometer. The influence of the volume of kerosene, the saponification rate, the concentration of rare earths, the kinds of rare earths and number of rare earths on the interfacial tension and viscosity have been discussed that increase the volume of kerosene would raise the interfacial tensions and lower the viscosity, and the increase of saponification rate brought the decrease of interfacial tension and increase of viscosity. The varied concentration of rare earths did not show great impact on the interfacial tension within a certain degree of saponification rate. Too low concentration and too high saponification rate would raise emulsification, which would hinder the measurements. Different kinds and number of rare earths presented little difference on interfacial tensions for their similar properties. CFD simulations in settler with different P507-kerosene systems have been conducted and the results showed that the phase separation was tougher with lower interfacial tension and higher viscosity.

    Effect of nano-particles on droplet coalescence in microchannel device
    WANG Kai, YI Shiting, ZHOU Qianqian, LUO Guangsheng
    2016, 67(2):  469-475.  doi:10.11949/j.issn.0438-1157.20151273
    Abstract ( 183 )   PDF (2276KB) ( 435 )  
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    Pickering emulsion is a liquid/liquid system stabilized by nano-particles. Microfluidic technology is an important method for preparing monodispersed Pickering emulsions. The droplet coalescence rule for the working system containing nano-particles is a core scientific issue for proceeding this new method. Using n-octanol and water as the continuous and dispersed phases respectively, the droplet collision processes in a broadening microchannel with a hexagon shape were investigated. Three typical flows (droplet coalescence, contact without coalescence and contactless) were confirmed. The effects of flow rate, nano-particle concentration and wetting property of nano-particles on the droplet coalescence percentage were studied. In addition, the working mechanism of nano-particles in the liquid film drainage processes were analyzed.

    Measurement of flooding gas velocity in packed column by acoustic emission technique
    FAN Xiaoqiang, HE Lelu, HUANG Zhengliang, YE Xiangqun, LI Yong, WANG Jingdai, YANG Yongrong
    2016, 67(2):  476-484.  doi:10.11949/j.issn.0438-1157.20150567
    Abstract ( 93 )   PDF (3233KB) ( 197 )  
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    The acoustic emission (AE) signal characteristics under different operation conditions of packed column were investigated by analyzing standard deviation (STD), power spectrum density (PSD) and multi-scale wavelet transform of acoustic emission signals. Criterions to determine the flooding gas velocity were proposed. The influence of liquid flowrate was investigated by air-water experiments. It was found that the prediction of the flooding gas velocity by AE signal STD was close to that by pressure drop. The power spectrum density of acoustic emission signals under different operation conditions showed that the maximal PSD peak transferred from around 50 kHz and 60 kHz to around 25 kHz when the packed column flooding. 7 scales wavelet transform was used to investigate the acoustic emission signals. Energy fraction of G1 (d4,d5) scale had a sharp rise as the gas velocity came to flooding gas velocity. The prediction of flooding gas velocity by G1 scale energy fraction was close to that by pressure drop. As a non-invasive method, acoustic emission detection can monitor flooding accurately and have a good application prospect.

    Dispersion of minor PS-MAMA component in polymer melt under two mixing modes
    ZHANG Cailiang, JIN Zuyu, GU Xueping, FENG Lianfang
    2016, 67(2):  485-493.  doi:10.11949/j.issn.0438-1157.20151243
    Abstract ( 80 )   PDF (1119KB) ( 205 )  
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    This work synthesized a macromolecular fluorescent-tracer (PS-MAMA) via the copolymerization of styrene (St) and 3-isopropenyl-α,α-dimethylbenzyl isocyanate (TMI) followed by reacting with 9-(methylaminomethyl) anthrance. The dispersion behaviors of PS-MAMA as a minor component in polystyrene (PS) and polymethylmethacrylate (PMMA) were investigated in a homemade batch mixer under two mixing modes. Results showed that for the steady mixing mode in which two rotors rotated together in an opposite direction, the minor component could form a stable laminar flow in a shorter time but the mixing between those layers was very slow; while for the square-wave mixing mode in which two rotors rotated alternately in an opposite direction, the PS-MAMA dispersion in the layer and between layers were poor in the initial mixing stage but the alternate rotation of two rotors can facilitate the exchange between the layers and accelerate the dispersion of minor component PS-MAMA in polymer melt. Therefore, the mixing ability of the square-wave mixing mode was better than that of the steady mixing mode.

    Pressure fluctuation in gas-solid agitated fluidized bed
    ZHANG Yongjun, WANG Jiajun, GU Xueping, FENG Lianfang
    2016, 67(2):  494-503.  doi:10.11949/j.issn.0438-1157.20151253
    Abstract ( 116 )   PDF (2266KB) ( 188 )  
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    Gas-solid agitated fluidized beds can be used to improve the fluidization performance of sticky polymer particles. Experimental pressure fluctuation signals were analyzed with statistics analysis, power spectrum analysis and wavelet analysis for investigating the influence of agitation speeds and types of agitators on the fluidization characteristic. Due to the effects of suppression and breakage on bubbles caused by agitation, lower pressure fluctuation amplitude and smaller bubbles were found in the agitated fluidized bed compared to general fluidized bed. The synergy between gas flow and agitation occurred in the agitated fluidized bed. For a gas-solid fluidized bed with an anchor impeller or a frame impeller, sufficiently high agitation speed was needed to improve fluidization performance. However, for self-cleaning agitator, higher agitation speed engendered adverse phenomena of gas short circuit and particles accumulation near the blades. Therefore, the feasible agitation speed was recommended for extending the application of the new self-cleaning agitator in industry.

    Formation and size prediction of slug droplet in viscoelastic fluid in flow-focusing microchannel
    ZHANG Qindan, FU Taotao, ZHU Chunying, MA Youguang
    2016, 67(2):  504-511.  doi:10.11949/j.issn.0438-1157.20151056
    Abstract ( 107 )   PDF (1265KB) ( 389 )  
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    A high-speed camera was utilized to observe the formation of the droplet in viscoelastic fluid in flow-focusing microchannel. The microchannel with a square section of 600 μm×600 μm was used in the experiment. Silicone oil and polyethylene oxide (PEO) solution (0.1%,0.3%,0.6%) with 0.3% surfactant sodium dodecyl sulfate (SDS) were used as dispersed and continuous phases, respectively. Three flow patterns were observed: slug flow, dripping flow and jetting flow. The transition lines for different flow patterns were obtained. The dynamics of breakup for slug droplets was studied. The effects of two-phase flow rates, capillary number and elasticity number of the continuous phase on the size of slug droplet were investigated experimentally. The results indicated that the size of slug droplet decreased with increasing flow rate, capillary number and elasticity number of the continuous phase, but it increased with increasing flow rate of the dispersed phase. The impact of the elasticity of the continuous phase on slug droplet size was relatively small. The correlations for predicting the size of slug droplet were proposed by taking the ratio of two-phase flow rates, and the capillary number and Reynolds number of the continuous phase into account. The prediction result agreed well with the experimental data.

    Heat transfer experiment of falling-film evaporation in vertical porous tube
    FAN Yongjian, XU Hong, XU Peng
    2016, 67(2):  512-518.  doi:10.11949/j.issn.0438-1157.20150614
    Abstract ( 85 )   PDF (571KB) ( 133 )  
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    This paper presents the effect of internal sintered porous tube on the falling-film evaporation heat transfer coefficients. The experiment was performed with a single-tube evaporator, using steam in the shell to heat water in the tube. The falling-film evaporation heat transfer coefficients were calculated under various conditions with heat flux from 13 kW·m-2 to 90 kW·m-2, heat transfer temperature difference from 2.87℃ to 9.5℃, and liquid Reynolds number from 4500 to 15000. The experimental results with a smooth tube are compared to those with an internal sintered porous tube. The results show that the falling-film evaporation heat transfer coefficients of an internal sintered porous tube are 2.03 times that of smooth tube, while the overall heat transfer coefficients are 1.78 times. The enhancement effects for heat transfer of internal sintered porous tube are obvious.

    3D numerical simulation of flow characteristics for Geldart B and Geldart D particles in gas phase ethylene polymerization fluidized-bed reactor
    CHE Yu, TIAN Zhou, ZHANG Rui, GAO Yuxin, ZOU Enguang, WANG Sihan, LIU Boping
    2016, 67(2):  519-529.  doi:10.11949/j.issn.0438-1157.20151205
    Abstract ( 109 )   PDF (8039KB) ( 476 )  
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    The status of polyethylene (PE) particle size and distribution, bubble generation and movement, and polymerization reaction in gas phase ethylene polymerization fluidized-bed reactor (FBR) is significant for PE production process, reactor design, optimization and control. Based on 3 dimensional (3D) Eulerian-Eulerian two-fluid model combined with a population balance model (PBM), this work aims to explore the two-phase flow characteristics and the effects of traditional PE production process (Geldart B particles) and non-pelletizing PE production process (Geldart D particles) on the operating behaviors in a pilot-plant FBR. The simulation results match well with the industrial measured pressure drop and temperature data. It is also found that the polymer particles observably concentrated on the bed inlet region for the effects of Geldart D particles and superfical gas velocity. In addition, the obvious vortexes and large bubbles can be clearly observed in the bed height direction. The results could provide foundation for the extension and application of the non-pelletizing PE production process.

    Characteristics of vibration displacement signals of graphite tube in fluidized bed evaporator
    AN Min, LIU Mingyan, XU Xiaoping
    2016, 67(2):  530-539.  doi:10.11949/j.issn.0438-1157.20151541
    Abstract ( 79 )   PDF (1143KB) ( 165 )  
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    The characteristics of vibration displacement signals of graphite tube in vapor-liquid-solid (V-L-S) external circulating fluidized bed evaporator were investigated by means of accelerometers and a system of measurement and analysis of dynamic vibration signals using signal analysis tools of the standard deviation, power spectrum and wavelet transformation. Main results were as follows. The original and global vibration displacement signal with multi-scale behavior can be decomposed into low and middle vibration displacement signal (LFS/MFS) and high frequency vibration displacement signal (HFS). The standard deviation of the original signal (under V-L-S boiling flow) and its LFS/MFS by wavelet transformation increased at first and then a stable trend with increasing steam pressure, and its HFS by wavelet transformation showed a slight increasing trend. The addition of solid particles can weaken the vibration intensity of LFS/MFS and enhance the vibration intensity of HFS. The standard deviation of HFS represented an apparent increasing trend with the solid holdup. The standard deviation of three vibration signals (original, LFS/MFS, HFS) indicated a weak enhancement with solid particle diameter. The vibration behavior of graphite tube at different axial positions was also investigated. Two correlations of vibration intensity for vapor-liquid and V-L-S boiling flows were provided.

    Effect of silica chemistry on structure of Ir-Re bimetallic catalysts and catalysis for glycerol hydrogenolysis
    LENG Li, ZHANG Hong, REN Xin, ZHOU Jinghong, SUI Zhijun, ZHOU Xinggui
    2016, 67(2):  540-548.  doi:10.11949/j.issn.0438-1157.20151512
    Abstract ( 99 )   PDF (2195KB) ( 369 )  
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    As an alternative process to petroleum based processes, hydrogenolysis of biomass-derived glycerol to 1, 3-propanediol (1, 3-PD) can be effectively catalyzed by bimetallic Ir-Re catalyst. However it still suffers from low selectivity of 1, 3-PD and low reaction rate. With extension of our previous study, silica was selected as a promising catalyst support to investigate the role of silica chemistry in the Ir-Re catalyst for glycerol hydrogenolysis. Bimetallic Ir-Re catalysts supported on three kinds of silica supports of KIT-6, G-6 and FS were prepared for glycerol hydrogenolysis to produce desired 1, 3-PD. The structure of catalysts were characterized by varied techniques of N2 adsorption-desorption, transmission electron microscopy (TEM), X-ray diffraction (XRD), H2 temperature-programmed reduction (H2-TPR), in-situ CO adsorption diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and temperature-programmed desorption (TPD) of ammonia. Also, the structure-activity relationship of the catalysts was discussed. It showed that the bimetallic catalysts on three silica supports possessed alloy structure of Ir-Re on surface, of which the order of alloy degree follows Ir-Re/KIT-6 > Ir-Re/FS > Ir-Re/G-6. Hydroxyl groups on support surfaces significantly affected the degree of metal dispersion and the interaction between active metallic components and support. The Ir-Re/FS catalyst possessed the highest degree of metal dispersion and exhibited the best initial activity but the worst stability for glycerol hydrogenolysis, while the Ir-Re/KIT-6 catalyst featured the highest degree of alloy thus showed excellent catalytic performance and the highest selectivity to 1, 3-PD of desired product.

    Effect of support basicity on iron-based catalysts for Fischer-Tropsch synthesis
    ZHANG Jun, ZHANG Zhengpai, SU Junjie, FU Donglong, DAI Weiwei, LIU Da, XU Jing, HAN Yifan
    2016, 67(2):  549-556.  doi:10.11949/j.issn.0438-1157.20151251
    Abstract ( 212 )   PDF (881KB) ( 322 )  
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    Lower hydrocarbons are key building blocks in chemical industry. The Fischer-Tropsch synthesis has been considered as one of the most promising non-oil based routes for lower hydrocarbons production. Previous studies have demonstrated that the supports can greatly affect the product distribution. In this work, the effects of the base property of supports on the catalytic performance of different Fe-based catalysts (Fe20/AlPO4, Fe20/γ-Al2O3 and Fe20/MgAl2O4) were investigated. The results showed that, with the increase in support basicity, the chain growth probability (α value), the selectivity of C5+ hydrocarbons and the olefins/paraffin ratio increased. Moreover, by combining with the Raman and temperature programmed hydrogenation (TPH), it was found that the higher basicity of supports could lead to the less active carbon (absorptive and atomic carbon) and the more inactive carbon (graphitized carbon) formation. In addition, with the combination of other characterization, such as XRD, H2-TPR, CO2-TPR, the structure-performance relationship was constructed. The variation in electron-donating ability of the supports strongly affected the content of carbonaceous species on the catalyst surface and the metal-support interaction, thereby leading to the difference in catalytic activity and selectivity.

    Experimental study on reactor integrating catalytic combustion and steam reforming for 1 kW SOFC-CHP
    ZHANG Li, XING Yaohua, ZHONG Jie, XU Hong, CAO Jun
    2016, 67(2):  557-562.  doi:10.11949/j.issn.0438-1157.20150926
    Abstract ( 99 )   PDF (1794KB) ( 341 )  
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    A reactor integrating catalytic combustion, heat exchange and steam reforming was developed for a 1 kW solid oxide fuel cell-combined heating and power system (SOFC-CHP). Experiments were carried out to investigate the effect of combustion gas components and process parameters on properties of the reactor. The results showed that methane conversion rate was 73.6% and hydrogen concentration in the exhaust gas was 67.5% under operating conditions at the inlet temperature of combustion gas of 300℃, air-fuel ratio of 10:1, fuel utilization of stacks of 65% and water-carbon ratio of 3:1. Fuel utilization of the SOFC stacks had significant effect on methane conversion. Waste heat recovery from the exhaust gas combustion cannot provide enough heat for methane steam reforming when the fuel utilization was greater than 80%. Reduction of the inlet temperature of combustion gas had slight effect on methane conversion in the range of 150-350℃. Thus, it was recommended that the heat exchange can be firstly conducted before catalytic combustion to improve heat efficiency without obvious change to reforming reaction efficiency. Reduction of air-fuel ratio under the premise of ensuring the efficiency of reforming can decrease power consumption of the compressor and increase the system efficiency. This achievements can provide guidance to the increase of the whole system efficiency and optimum design of SOFC-CHP.

    Influence of catalyst shape on methane steam reforming and simulation of industrial reactor
    QIN Wen, ZHOU Zhiming, CHENG Zhenmin
    2016, 67(2):  563-572.  doi:10.11949/j.issn.0438-1157.20151252
    Abstract ( 161 )   PDF (1014KB) ( 270 )  
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    Methane steam reforming (MSR) is the most widely used technology for hydrogen production in industry now, where the shape of catalyst particles and the reactor operating conditions greatly influence the reactor performance and the product composition. Firstly, the present study investigated the effect of catalyst shape (sphere, cylinder and ring) on the MSR using a diffusion-reaction model on the particle scale. The effectiveness factors of shaped catalysts followed the sequence: cylinder < sphere < ring. Next, a one-dimensional mathematical model was developed by taking into account the mass, heat and momentum transfer on the reactor scale together with the diffusion-reaction equations on the catalyst scale, and used to describe an industrial MSR reactor. The effects of inlet temperature and pressure on the profiles of temperature and pressure inside the reactor, effectiveness factor, conversion of methane as well as concentration of various species were studied. Finally, the optimal inlet temperature and pressure for the industrial reactor were determined, being 773 K and 3 MPa, respectively.

    Simulation and analysis of operation flexibility of divided wall column for ternary distillation
    MU Zulin, GE Xiaolong, YUAN Xigang, LUO Yiqing, Kuo-Tsong Yu
    2016, 67(2):  573-579.  doi:10.11949/j.issn.0438-1157.20151531
    Abstract ( 87 )   PDF (738KB) ( 141 )  
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    The operation and control of a dividing-wall column, a fully thermally coupled distillation column configuration, is more complex than the traditional column because of its coupling nature. However it exhibits more flexibility due to the more degree of freedom. In the present paper the operation flexibilities of dividing-wall columns for separating the mixture of n-pentane, n-hexane and n-heptane with different compositions are investigated by using rigorous simulation. And the effect of the feed composition on the operation flexibilities are also investigated.

    Simulation of thermally coupled catalytic distillation flowsheets for C3 alkyne selective hydrogenation
    WANG Yizhuo, LUO Yiqing, QIAN Xing, YUAN Xigang
    2016, 67(2):  580-587.  doi:10.11949/j.issn.0438-1157.20151225
    Abstract ( 97 )   PDF (519KB) ( 178 )  
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    In order to reduce effectively the refrigeration cost for the process of selective hydrogenation of C3 alkyne into alkene, three novel thermally coupled catalytic distillation flowsheets are proposed. In the proposed flowsheets, the reactor for catalytic hydrogenation of C3 components is settled in the lower part of the deethanizer in the original process and the three columns are thermally coupled in different ways. The proposed flowsheets are rigorously simulated and evaluated. The results show that, compared with original process, the proposed processes raise the convert ratio of hydrogenation, and at the same time, significant energy saving can be achieved by the thermal couplings, leading to a decrease in the total annual cost by 4.107%, 6.420% and 10.337% respectively for the three proposed flowsheets.

    Optimization of reactive extraction-crystallization process based on response surface methodology
    LI Yunzhao, SONG Xingfu, SUN Yuzhu, SUN Ze, YU Jianguo
    2016, 67(2):  588-597.  doi:10.11949/j.issn.0438-1157.20151171
    Abstract ( 99 )   PDF (4636KB) ( 201 )  
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    The preparation of calcium carbonate and hydrogen chloride from calcium chloride and carbon dioxide by the reactive extraction-crystallization coupled process is an effective way for the utilization of alkaline waste liquid. In this paper, Box-Behnken Design (BBD) in response surface methodology was used to design the experiments to investigate the effects of concentration of calcium chloride (CaCl2), volume fraction of extractant, phase ratio, and temperature on the conversion of CaCl2, concentration of hydrogen chloride (HCl) in organic phase, and the average particle size of calcium carbonate (CaCO3) in the reactive extraction-crystallization coupled process, respectively. Three quadratic models were developed to correlate the variables to the response values and were proved to be significant. The optimal values were found as follows: conversion of CaCl2 95.08% and 92.35%, concentration of HCl in organic phase 1.126 mol·L-1 and 1.123 mol·L-1, and average particle size of CaCO3 48.71 μm and 49.14 μm. The small errors between the predicted and experimental values showed that the established models were accurate and reliable for the analysis and prediction of the reactive extractioncrystallization process.

    Sensitivity analysis and optimization of vacuum pressure swing adsorption process for N2/CH4 separation
    SUN Weina, YAN Haiyu, ZHANG Donghui
    2016, 67(2):  598-605.  doi:10.11949/j.issn.0438-1157.20151085
    Abstract ( 106 )   PDF (610KB) ( 200 )  
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    This paper firstly conducted the experiments for N2/CH4 separation using the vacuum pressure swing adsorption (VPSA) process based on the two-bed experimental set-up and the laboratory-made coconut shell-based activated carbon as adsorbent. The PSA mathematical models were verified by comparing the separation results of experiments and simulations employing gPROMS dynamic simulation software. On this basis, sensitivity analyses were made on the key decision variables affecting product CH4 purity and recovery. Sensitivity analysis indicated that the product purity mainly depended on the raw gas flow and displacement gas flow, while product gas recovery required a good combination of the three key variables. The results showed that the purity of the product gas was mainly regulated by the raw gas flow and displacement gas flow, while a common action of the key variables was required in order to maximize the product gas recovery. Based on the results of the sensitivity analysis, the dynamic optimization was studied for PSA process under consideration. Under optimal conditions, the molar concentration of CH4 may be enriched to 75% and product recovery can be enhanced to 97.08% with feed concentration of 35%. This optimal VPSA process has proved its practicality for the effective recycling of waste gas mixture.

    Synthesis of ethyl acetate via reactive and extractive distillation column using ionic liquids as catalyst and entrainer
    JIE Huimin, CUI Xianbao, PENG Yanmei, LI Xiaobing, XU Li, LIN Ruirong
    2016, 67(2):  606-613.  doi:10.11949/j.issn.0438-1157.20151227
    Abstract ( 165 )   PDF (659KB) ( 294 )  
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    Transesterification of methyl acetate with ethanol to produce ethyl acetate and methanol via reactive and extractive distillation (RED) was simulated, using ionic liquids, 1-sulfobutyl-3-methyllimidazolium hydrogensulfate [HSO3bmin][HSO4] and 1-butyl-3-methylimidazolium bis[(trifluoromethyl) sulfonyl]imide ([BMIM][Tf2N], as catalyst and entrainer respectively. Based on the analysis of vapor-liquid equilibrium and reaction kinetics, a reactive and extractive distillation process was developed. The effects of number of theoretical stages, reflux ratio, liquid holdup, feed locations, entrainer ratio (the ratio of solvent mole flowrate to feed mole flowrates) and catalyst flowrate on RED process were investigated. The simulation results indicated that the purities of ethanol and ethyl acetate were 0.9922 and 0.9905 (mole fraction), respectively, and the conversion of methyl acetate was 0.9922 under the optimal operating and structural conditions.

    Performance and optimization of Sm3+ extraction by microcapsules containing P507
    WANG Yue, JING Yu, WANG Yundong, YU Yanmei
    2016, 67(2):  614-622.  doi:10.11949/j.issn.0438-1157.20151127
    Abstract ( 57 )   PDF (4394KB) ( 180 )  
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    To solve the problems of phase separation difficulty, extractant loss and large equipment existing in the liquid-liquid extraction system, a solvent extraction method with coaxial microchannel device was applied to prepare polysulfone microcapsules and the extraction performance of Sm3+ by microcapsules containing P507 was investigated and optimized. Extraction kinetics, stripping property and stability of microcapsules containing P507 was studied systematically. The advantages of microcapsule system were highlighted, i.e., simple operation, little extractants loss and high stability. To enhance the mass transfer, and improve extraction and stripping rate, P507 was diluted with kerosene and the extraction performance in the liquid-liquid system was studied. The best extraction performance was obtained when the volume fraction of P507 in solution was 40%. Compared with microcapsules containing pure P507, the extraction performance of microcapsules containing 40%(vol) P507/60%(vol) kerosene was significantly promoted-the extraction equilibrium time was shortened from 120 min to 40 min, the equilibrium capacity was improved from 45.09 mg·(g P507)-1 to 69 mg·(g P507)-1, the utilization of P507 was increased from 55% to 84%, and the equilibrium stripping time was decreased from 600 min to 120 min. In conclusion, the diluting P507 with kerosene can effectively improve the extraction kinetics, equilibrium extraction capacity and stripping rate. 20 cycles of extraction and stripping demonstrated a good stability of microcapsules after diluting P507 with kerosene.

    Synthesis of cinnamic acid-based ionic liquids and application in CO2 absorption
    CHEN Kaihong, MEI Ke, LI Haoran, WANG Congmin
    2016, 67(2):  623-626.  doi:10.11949/j.issn.0438-1157.20151217
    Abstract ( 146 )   PDF (433KB) ( 273 )  
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    A series of cinnamic acid-based ionic liquids [P66614][CIN] were prepared and applied in the CO2 absorption. The results showed that the cinnamic acid-based ionic liquids exhibited good CO2 absorption performance. The CO2 absorption ability was influenced by the substituent in the cinnamic acid. The CO2 absorption capacity would decrease with increasing temperature or decreasing pressure. Furthermore, these ionic liquids exhibited excellent reversibility since higher CO2 absorption capacity can be maintained after 5 times of absorption/desorption circulation. The results of a combination of FT-IR spectrum and CO2 absorption under 10% CO2 indicated that CO2 was absorbed by chemisorption.

    Corrosion and deposition properties on anodization coatings of titanium dioxide nanotubes in geothermal water
    ZHANG Fan, LIU Mingyan, XU Yangshuhan
    2016, 67(2):  627-640.  doi:10.11949/j.issn.0438-1157.20151064
    Abstract ( 129 )   PDF (8565KB) ( 393 )  
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    In this paper, surface engineering technique of two-step anodization was used to solve the problems of corrosion and fouling in the geothermal water. TiO2 nanotube layers were prepared on the substrates of pure titanium and its alloy (Ti-6Al-4V), and factors affecting layer structure were explored. Hydrophobization was further applied on the surface of TiO2 coatings by immersion method. Microstructures of TiO2 nanotubes were characterized by SEM. Static contact angle was obtained on the coatings via optical contact angle measuring device, and surface free energy was calculated. Roughness of the coatings was measured. Fouling property of coatings was investigated by static immersion experiments in CaCO3 fouling solution. Corrosion property of coatings in geothermal water was investigated by potentiodynamic polarization curve. Well-aligned array of TiO2 nanotubes and micro- and nano-scale coatings with low surface free energy were obtained on substrates of pure titanium and its alloy under optimal conditions of two-step anodization and immersion techniques. The TiO2 coatings showed anticorrosion ability in geothermal water and antifouling property in saturated solution of CaCO3. Compared with pure titanium and its alloy, fouling deposition rate decreased by 15% on the coatings. Meanwhile, the coatings displayed good mechanical durability through maintaining hydrophobicity after many times of tape-peeling and abrasion tests.

    Molecular dynamics simulation of rupture of lipid bilayer under dynamic surface tension
    KONG Xian, HU Xiaoyu, LU Diannan, LIU Zheng
    2016, 67(2):  641-647.  doi:10.11949/j.issn.0438-1157.20151147
    Abstract ( 122 )   PDF (6396KB) ( 394 )  
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    The biocompatible nature of lipid bilayer makes it appealing for wide applications including biosensor, biomimetic membrane for separation or reaction. Understanding lipid bilayer rupture is of fundamental importance for the design and application of lipid bilayer based devices. In the present study, a lipid bilayer membrane made by dipalmitoyl phosphatidylcholine (DPPC) and dipalmitoyl phosphoglycerol (DPPG) was used for the molecular dynamics simulation of the lipid bilayer rupture. A method for determining the rupture time and the critical surface tension was proposed, based on which, the effects of lipid bilayer composition on the lipid bilayer rupture were examined. It was shown that an increase in the negatively charged DPPG in the lipid bilayer postponed the rupture time, indicating a strengthened structural stability. On the other hand, the widened distribution of the rupture time indicated the heterogeneous nature of the lipid bilayer. A dynamic microscopic opposing forces model was proposed to describe the above mentioned lipid bilayer rupture under an unsteady surface tension. The model had reproduced the simulation results and thus offered theoretical tools for the design and optimization of the lipid bilayer based devices and processes.

    Effects of acid-base catalysts concentration on structures and properties of flexible silica aerogels
    CAI Long, PU Qun, QU Kang, SHAN Guorong
    2016, 67(2):  648-653.  doi:10.11949/j.issn.0438-1157.20150600
    Abstract ( 95 )   PDF (2170KB) ( 310 )  
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    Flexible silica aerogels with super-hydrophobicity and elasticity were successfully prepared via acid-base two-step sol-gel method, followed by supercritical drying process. They were synthesized with tetraethoxysilane (TEOS) and methyltrimethoxysilane (MTMS) as coprecursors, methyl alcohol as solvent and cetyl trimethyl ammonium bromide (CTAB) as surfactant. The influence of acid-base catalysts concentration on silica aerogels was studied in detail. Aerogels prepared with higher base concentration and lower acid concentration were found to have more uniform pore structures and narrower pore size distributions. It was observed that the optimum aerogels can be obtained with 0.01 mol·L-1 oxalic acid and 5 mol·L-1 ammonia as acid-base catalysts, respectively. The density of the as-prepared aerogel was as low as 0.135 g·cm-3, the porosity was around 93% and the specific surface area was as high as 807 m2·g-1. The maximum compression ratio of the aerogel was as high as 60% with 100% compression resilience ratio.

    Fabrication and hydrophilic properties of polysulfone/modified multiwalled carbon nanotube composite membranes
    SHI Jingyuan, WANG Wenyi, WANG Jinlong, GAO Ningning, LI Yanling, WANG Enxia, HUO Tengbo
    2016, 67(2):  654-660.  doi:10.11949/j.issn.0438-1157.20151096
    Abstract ( 110 )   PDF (8238KB) ( 390 )  
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    The polysulfone(PSF)/modified multiwalled carbon nanotube(MWCNTs-COOH) composite membranes were formed via phase inversion process. The membranes used PSF as film-forming materials, MWCNTs-COOH as additives, polyvinyl pyrrolidone(PVP) as pore-foaming agent and N,N-dimethylacetamide as solvent. The effects of MWCNTs-COOH constitution, solvent evaporation time and coagulation bath composition on the composite membranes were studied systematically. Experiment results showed that the hydrophilic property and anti-pollution ability of composite membranes were improved remarkably. In addition, the mechanical property was also improved significantly. SEM images showed that the porous structure of cross-section changed from finger type to sponge type when the solvent evaporation time increased or the DMAc mass fraction increased of the coagulation bath, the pure water flux was declined and the BSA rejection was increased observably.

    One-way shape memory behavior of thermoplastic polyolefin elastomers
    HUANG Limei, GUO Song, ZHAO Qian, XIE Tao, LI Bogeng
    2016, 67(2):  661-666.  doi:10.11949/j.issn.0438-1157.20151234
    Abstract ( 109 )   PDF (2954KB) ( 358 )  
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    Thermoplastic polyolefin elastomers which are soft and easy processing have potential usage for non-structural applications. The thermal, mechanical and shape memory properties of this thermoplastic elastomers were investigated with differential scanning calorimetric (DSC) and dynamic mechanic analysis (DMA). The results showed that was important for the better shape memory with both of the shape fixity rate and shape recovery rate up to 90% can be reached by choosing a proper deforming temperature in a broad range of melting temperature.

    Preparation of high impact polypropylene with high ethylene content by gas phase process
    DA Wenzhong, XIAO Zhixian, XU Hongbin, TU Yuxia, MEI Li, YAO Zhen, CAO Kun
    2016, 67(2):  667-671.  doi:10.11949/j.issn.0438-1157.20151354
    Abstract ( 83 )   PDF (3264KB) ( 223 )  
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    In the production of high impact polypropylene (hiPP) by in-reactor processes, the ethylene content of hiPP was limited at a low level for the lack of a suitable antisticking method and that by now a deficient antisticking method with low purity nitrogen (LPN) was commonly adopted. A new antisticking method by in-situ adding tiny (<0.1%) superfines was adopted in Hypol process to produce hiPP with high ethylene content (>20%) and good flowability, showing the possibility to take the place of LPN method. Moreover, the comparison of the product with hiPP prepared by LPN method showed that the anti-impact performance rose from 36.44 kJ·m-2 to 60.56 kJ·m-2 at 23℃ and from 14.78 kJ·m-2 to 35.12 kJ·m-2 at -20℃, respectively. It was found that hiPP with high ethylene content presented excellent anti-impact performance at both 23℃ and -20℃.

    Synthesis, characterization and lubricating effect of long chain branched polydimethylsiloxane-g-polyethylene copolymers
    JIN Zhen, FAN Hong
    2016, 67(2):  672-678.  doi:10.11949/j.issn.0438-1157.20151239
    Abstract ( 113 )   PDF (500KB) ( 379 )  
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    Long chain branched polydimethylsiloxane-g-polyethylene (PDMS-g-PE) copolymers were synthesized by hydrosilylation reaction between polymethylhydrosiloxane and vinyl terminated PE macromonomer. The structure and properties were characterized by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (1H NMR), high temperature gel permeation chromatography (HT-GPC) and differential scanning calorimetry (DSC). The effect of the hydrogen content of polymethylhydrosiloxane on the copolymer structure and properties was investigated. It was found that the molecular weight of PDMS-g-PE increased with the hydrogen content of polymethylhydrosiloxane since more PE macromonomers were grafted onto the polydimethylsiloxane main chains. The glass transition temperature (Tg) of PDMS-g-PE was extremely low, indicating the excellent molecular chain flexibility. PDMS-g-PE with more PE branched chains showed higher melting temperature (Tm) and higher melting enthalpy (ΔHm). PDMS-g-PE was used as flow modifier for HDPE. When 2% PDMS-g-PE was added to HDPE, the melting flow rate (MFR) increased by 21%, the elongation at break improved significantly and the impact strength improved a little, while the tensile strength and elastic modulus decreased slightly.