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Table of Content
25 February 1994, Volume 45 Issue 1
    化工学报
    HYDRODYNAMIC INSTABILITY OF CASTING FILM SOLUTION AND OPTIMUM THICKNESS OF ULTRATHIN MEMBRANE
    Wang Zhi and Wang Shichang (Chemical Engineering Reaeach Center, Tianjin University, Tianjin 300072)
    1994, 45(1):  1-9. 
    Abstract ( 701 )   PDF (520KB) ( 254 )  
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    Theoretical and expermental researches have been made on the hydrodynamic in-stabililty of casting film solution and the formation of an ultrathin membrane. The results show that the hydrodynamic instability of the solution leads to forming holes in the skin layer of the membrane. The solution thickness on the solid support during the ultrathin film casting operation is significantly responsible for hydrodynamic instability. With an optimum thickness of ultrathin membrane, the instability can be suppressed and the holes in the skin layer can be reduced or eliminated, so that the ultrathin composite membrane will have high rejection as well as high water flux.
    TWO-DIMENSIONAL AGITATED FLOW FIELDS OF HIGHLY VISCOUS FLUIDS
    Chen Mei, Fan Xijun, Dou Mei and Wu Jia (Department of Chemical Engineering and State Key Laboratory of CAD & CG, Zhejiang University, Hangzhou 310027)
    1994, 45(1):  10-16. 
    Abstract ( 621 )   PDF (401KB) ( 144 )  
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    The Navier-Stokes equations for two-dimensional agitated flow in the polar coordinates are solved with the finite element method. The penalty function and integration reduction techniques were used in the finite element formulation to treat the incompressibility constraint of fluids and eliminate the pressure term in the momentum equation. The velocity distribution, flow patterns and shear - rate distributions were successfully calculated for the 2-D agitated flow field induced by an anchor impeller. The good agreement of the calculated flow patterns with those obtained experimentally indicated the reasonableness of the present treatment. Numerical simulation was further carried on for various values of Reynolds number, and the influence of Reynolds number on the agitated flow fields was discribed.
    HYDRODYNAMICS AND MASS TRANSFER CHARACTERISTICS IN A SUPERCRITICAL FLUID EXTRACTION PACKED COLUMN (Ⅰ) HYDRODYNAMIC MODEL
    Zhang Chunhu, Zhang Zeting, Zhu Meiwen and Yu Enping (Department of Chemical Engineering, Beijing Institute of Chemical Technology, Beijing 100029)
    1994, 45(1):  17-23. 
    Abstract ( 796 )   PDF (340KB) ( 308 )  
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    A new model for describing two - phase flow in a supercritical fluid extraction packed column was derived whereThe model was tested by measuring the experimental data for two - phase flow characteristics in a supercritical fluid extraction packed column of 25mm in diameter with structured packings and θ metal rings for the systems of carbon dioxide-isopropanol-water and carbon dioxide - ethanol -water under pressures from 8 to 15MPa and at 35 C. It showed that the model for predicting hydrodynamic performance agrees well with the experimental data.
    HYDRODYNAMICS AND MASS TRANSFER CHARACTERISTICS IN A SUPERCRITICAL FLUID EXTRACTION PACKED COLUMN (Ⅱ) MASS TRANSFER PERFORMANCE
    Zhang Zeting, Zhang Chunhu, Zhu Meiwen and Yu Enping (Department of Chemical Engineering, Beijing Institute of Chemical Technology, Beijing 100029)
    1994, 45(1):  24-31. 
    Abstract ( 623 )   PDF (341KB) ( 234 )  
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    A study on mass transfer performance was carried out in a continuous countercur-rent supercritical fluid extraction packed column of 25mm in diameter filled with structured packings and θ metal rings for the testing systems of carbon dioxide-isopropanol-water and carbon dioxide - ethanol-water under pressures from 8 to 15MPa and at 35 ℃. The experimental data under steady state were used to estimate the parameters of mass transfer,NOLP, HOLP and KOLa,with a plug-flow model. A model based on two film theory for calculating overall volumetric mass transfer coefficient was developed and the model parameters, A,m and n,were estimated by nonlinear programming Where A= 0.012, m = 0.65, n = 0. 30 for structured packings A = 0.015, m =0. 70, n = 0. 30 for θ metal rings
    MONTE CARLO SIMULATION OF SPHERICAL AND LINEAR LENNARD-JONES MOLECULE MIXTURES
    Jia Chunshang, Wang Wenchuan and Lu Huanzhang (Department of Chemical Engineering, Beijing Institute of Chemical Technology, Beijing 100029)
    1994, 45(1):  32-37. 
    Abstract ( 535 )   PDF (276KB) ( 170 )  
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    A binary mixture consisting of spherical and linear Lennard-Jones molecules has been simulated by using the Monte Carlo method. Long range corrections for internal energy, pressure and chemical potential have been derived and implemented for the NPT ensemble simulation of the system. Macroscopic and excess properties of the sysem, i. e. volume, density and excess enthalpy, excess volumes, excess entropy have been calculated at different compositions. The results provide a basis for the simulation of chain-like and polymer molecule mixtures.
    COALESCENCE BETWEEN SMALL BUBBLES OR DROPS
    Li Dongming (Department of Chemical Engineering, Tianjin University, Tianjin 300072)
    1994, 45(1):  38-44. 
    Abstract ( 549 )   PDF (316KB) ( 282 )  
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    When two small drops or bubbles approach each other, a dimpled thin film is formed between them. A model is developed for the dynamics of the thinning film with tangential immobile interfaces, in which the London-van der Waals forces are taken into consideration. The model predicts the coalescence time, which is the time required for the thinning and rupture of the liquid film, by giving only the radii of the two drops and the required physical properties of the bulk fluid and interface. A more general expression for coalescence time is derived. The predicted result is in good agreement with previous experimental results.
    THE INFLUENCE OF RECIRCULATING FLOW AND SLIDING BUBBLES IN BOILING ON TUBE BUNDLE
    Wen Zhimin, Zhu Changxin and Zhou Fangde (Institute of Thermophysics Engineering, Xi an Jiaotong University,Xi an 710049)
    1994, 45(1):  45-50. 
    Abstract ( 574 )   PDF (248KB) ( 126 )  
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    Two mechanical models——recirculating flow and sliding bubbles, which lead to the bundle effect in nucleate boiling on tube bundle are established and calculated quantitatively. The correlation of nucleate boiling on tube bundle is put forward on the basis of experiments, and the influence on boiling heat transfer is analysed.
    CELL DISRUPTION KINETICS IN HORIZONTAL BEAD MILL
    Xiu Zhilong and Su Zhiguo (Dalian University of Technology, Dalian 116012)
    1994, 45(1):  51-57. 
    Abstract ( 748 )   PDF (361KB) ( 218 )  
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    The disruption kinetics of a microbial cell was studied by using a horizontal bead mill (Dyno -mill). A mechanism was put forward on the basis of experimental results and prior work. It was composed of the release of intracellular products,and their solubilization and inactivation during the cell disruption process. A new model of disruption kinetics was established, which was used to regress the experimental data and calculate the relevant parameters. The new kinetics equation could better explain the deactivation phenomena of intracellular products.
    MULTICOMPONENT DIFFUSION MODEL FOR EFFECTIVENESS FACTORS OF POROUS CATALYST (Ⅴ) FINITE ELEMENT METHOD FOR EFFECTIVENESS FACTORS OF SURFACE POISONED CYLINDRICAL CATALYST WITH EQUILIBRIUM DEAD ZONE
    Pan Tianshu, Ying Weiyong, Fang Dingye and Zhu Bingchen (Department of Chemical Engineering, East China University of Science and Technology,Shanghai 200237)
    1994, 45(1):  58-64. 
    Abstract ( 575 )   PDF (319KB) ( 124 )  
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    On the basis of the distinguishing features of two-dimensional reaction -diffusion equations describing the surface poisoned cylindrical catalyst with equilibrium dead zone, Finite Element Method (FEM) is used to solve this kind of problem, which is often difficult to solve for other methods. A comparison of calculated effectiveness factors with experimental data shows that FEM has the advantages of simplicity and accuracy and it is easy to be used to analogous systems.
    AN EXPERIMENTAL STUDY OF DOWN-PRESS STIRRING-TANK WITH MULTI-MIXER
    Zhao Bing, Lu Lizhu, Lin Pin and Zhang Jing (Institute of Chemical Metallurgy, Academia Sinica, Beijing 100080)
    1994, 45(1):  65-72. 
    Abstract ( 650 )   PDF (421KB) ( 110 )  
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    The down-press stirring tank with multi-mixer (DPSTMM), a new type of mixing tank, was developed, which consists of several mixing chambers in a vertical series. The fluid flows down from chamber to chamber in 0. 65 liter and 65 liter DPSTMM. The number of mixing time Nθm was obtained, the energy consumption per unit mass was measured and the axial mixing coefficients were determined by computer from the response curve of tracer concentration. Experiments were carried out in 65 L DPSTMM, with kerosene/oc-tanol (10 : 1,V/V) as continuous phase and water as dispersed phase. HAc transfers from water to kerosene/octanol. The overall coefficient of mass transfer, Koda, in different mixing chambers was calculated by means of cascade extraction principles to analyse the overall efficiency of scaled - up DPSTMM. The experimental results showed that DPSTMM had much better performance than continuous stirring reactor tank (CSRT) in hydrodynamics and mass transfer.
    FUZZY OPTIMIZATION DYNAMIC PROGRAMMING TECHNIQUE FOR MULTIOBJECTIVE AND MULTISTAGE SERIES SYSTEMS
    Xiong Deqi and Chen Shouyu (Department of Civil Engineering, Dalian University of Technology, Dalian 116023)
    1994, 45(1):  73-79. 
    Abstract ( 593 )   PDF (360KB) ( 98 )  
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    The fuzzy optimization dynamic programming technique for multiobjective and multistage series systems is developed by combining fuzzy optimization theory with dynamic programming technique. This is a new method for solving the optimization of multiobjective and multistage problems in chemical systems. Finally, an application to the optimization of a multiple reactor system is given.
    HEAT TRANSFER CHARACTERISTICS OF FIN-AND-TUBE HEAT EXCHANGER FOR NON-NEWTONIAN FLUID
    Wang Wenjun, Gu Peiyun, Sun Jianzhong and Pan Qinmin (National Polymerization Reaction Engineering Lab, Zhejiang University, Hangzhou 310027)
    1994, 45(1):  80-87. 
    Abstract ( 604 )   PDF (408KB) ( 241 )  
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    Heat transfer to medium and highly viscous non-Newtonian fluids in the fin-and -tube heat exchanger under the conditions of Re<2, 270 was studied. The correlation of heat transfer was also presented. The modified Wilsons method was used for processing the experimental data. In order to lessen the effect of flow maldistribution on the experimental results, a measurement method was put forward to study the flow distribution in the heat exchanger by determining the temperatures of fluids.
    A REACTION DIFFUSION MODEL FOR EXTRACTING SCANDIUM WITH EMULSION LIQUID MEMBRANE (ELM)
    Xu Tongwen and Fan Wenyuan (Department of Chemical Engineering, Hefei University of Technology, Hefei 230009)
    1994, 45(1):  88-93. 
    Abstract ( 513 )   PDF (282KB) ( 225 )  
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    An type Ⅱ interfacial reaction diffusion model for facilitating transport in the liquid surfactant membranes has been developed. Besides considering aqueous diffusion, membrane diffusion and interfacial chemical reactions as simultaneous controlling factors, the model includes the influence of the ELM breakage. The model quantitatively proven in the batch extraction of scandium is especially applicable to the low concentration solution (less than 0. 22 mmol/L)
    PHASE EQUILIBRIA UNDER SUPERATMOSPHERIC PRESSURES FOR BINARY SYSTEMS OF CYCLOHEXANE,1-BUTANOL AND TOLUENE
    Chen Genghua, Yan Xinhuan, Han Shijun, Ma Zhongming and Wang Qi (Department of Chemistry, Zhejiang University, Hangzhou 310027)
    1994, 45(1):  94-101. 
    Abstract ( 745 )   PDF (360KB) ( 173 )  
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    The vapor liquid equilibrium data for cyclohexane -1 -butanol, cyclohexane -toluene and 1-butanol-toluene binary systems were determined under pressures from 101. 3 to 911. 9 kPa with the dual circulating VLE apparatus. The data under five pressures were combined and correlated by the Wilson equation, and the relationship of the Wilsons energy parameters with pressures were determined for each system. Good results were obtained. The experimental data indicated that minimum boiling azeotropes were formed for cyclohexane- 1 - butanol and 1 - butanol-toluene binary systems under the studied pressures.
    DETERMINATION OF VERY LOW VAPOR PRESSURES OF SEVEN ORGANIC COMPOUNDS
    Yi Shouzhi Ma Peisheng and Ruan Yongsi (Department of Chemical Engineering, Jilin (Department of Chemical Engineering, Institute of Chemical Technology, JiLin 132022) Tianjin University, Tianjin 300072)
    1994, 45(1):  102-105. 
    Abstract ( 646 )   PDF (169KB) ( 210 )  
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    An experimental apparatus was established for determining very low vapor pressures by using the Knudsen weighing effusion method. The reliability of the apparatus was checked by measuring the low vapor pressures of n-hexadecane. Vapor pressures of 7 substances including n- octadecane, 1-octadecene, diethylphthalate, dimethylterephthalate, di-isopropylnaphthalene, dicyclohexylphthalate and pyrene were determined at temperatures from 298 to 373 K and correlated by the Antoine equation.
    CHARACTERISTICS OF MICROMIXING IN BATCH STIRRED TANK REACTOR
    Gu Peiyun, Sun Jianzhong, Pan Qinmin and Qian Wei (Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027)
    1994, 45(1):  106-111. 
    Abstract ( 596 )   PDF (321KB) ( 129 )  
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    With the second-order irreversible reaction of sodium hydroxide and ethyl acetate as working reaction, the average micromixing level of water and pseudo-plastic CMC fluids of different viscosities under various agitating conditions in the whole batch reactor was investigated. By comparing the theoretical analytic curves of micromixing model with the measured curves, the evaluation of micromixing states in the batch stirred tank reactor was carried out.
    ESTIMATION OF SURFACE TENSION AT 20 C WITH GROUP CONTRIBUTION METHODS
    Ma Peisheng, Li Ping , Zhao Xingmin, Li Shuhong and Liu Youling (Department of Chemical Engineering, Tianjin University, Tianjin 300072)
    1994, 45(1):  112-116. 
    Abstract ( 698 )   PDF (235KB) ( 322 )  
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    New group contribution methods for estimating surface tension at 20℃ were proposed for the first time. The estimation accuracy is superior to the corresponding state methods. Two proposed methods with good adaptability and reliability are recommended.
    SOLUBILITY OF TURPENTINE AND SEPARATION OF α-PINENE AND β-PINENE IN SUPERCRITICAL CARBON DIOXIDE
    Liu Xiongmin, Li Piaoying, Zou Dezheng and Li Fei (Research Institute of Fine Chemical Industry, Guangxi University, Nanning 530004)
    1994, 45(1):  117-119. 
    Abstract ( 595 )   PDF (144KB) ( 148 )  
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    The solubility of turpentine was studied in surpercritical carbon dioxide with NOVA-4L supercritical fluid extraction apparatus. Empirical correlation for calculating the solubility of turpentine of a mixture of compounds with similar properties was established with the average error of 3. 5 percent lny=-5.659-4.658/Tr+0.2721Trσr+1.304ln(Trσr)The separation characteristics of α- pinene and β- pinene in turpentine are discussed.
    MACROKINETICS OF SULFUR-TOLERANT METHANATION SDM-1 CATALYST
    Yu Jianguo,Yu Zunhong,Sun Xingyuan,Pan Huiqin and Yu Guangsuo (East China University of Science and Technology ,Shanghai 200237)
    1994, 45(1):  120-124. 
    Abstract ( 691 )   PDF (239KB) ( 137 )  
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    The macrokinetics of sulfur-tolerant methanation SDM - 1 4φ5×5 mm catalyst under conditions——0. 30-1. 20MPa, 573-673K, H251-54%, CO14-25%,CH42.5-14% , CO2 5. 3-9. 0% and N2 10. 2-13. 4% is studied in a gradientless reactor with internal -recycle. The macrokinetics model is as follows rCH4 = l. 3491 ×10-5exp[- 32777/ (RT) ]p0.83yCO0.51yH20.32rCO2=1.7014×10-6exp[-52311/(RT)]p1.56yCO0.50yH2O(1-β)1.60The kinetics equations are tested by mathematical statistic method and residual distribution. The result shows that the model is reasonable.