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Table of Content
25 February 1990, Volume 41 Issue 1
    化工学报
    Molecular Thermodynamic Model for Electrolyte Solutions
    Zuo Youxiang and Guo Tianmin (Beijing Graduate School, University of Petroleum, Beijing)
    1990, 41(1):  1-9. 
    Abstract ( 527 )   PDF (385KB) ( 169 )  
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    In this study, a new expression for the Helmholtz energy of mixtures containing electrolytes as a function of temperature, density and composition is presented on the basis of perturbation theory. It covers the entire fluid density range from zero to liquid-like densities, and can be used for both phases in vapor-liquid equilibrium calculations. The new expression consists of hard sphere, electrostatic charge and attraction contributions to the Helmholtz energy. For mixtures without electrolytes the equation resembles the equation developed by Hu et al. (1985).For pure molecular components, the parameters are obtained by fitting experimental pure component vapor pressuer, saturated-liquid and saturated vapor density data. The ion-ion interaction parameters are obtained from regressing mean ionic activity coefficient data. The equation of state has been used to correlate mean ionic activity coefficients for twenty-five aqueous electrolyte solutions. Meantime, other four comparable models (Bromley, Meissner, Pitzer, Chen) are compared by using the same set of experimental data. The model presented in this work gives the best representa tions, the Bromley model and the Meissner model are not quite as good, and the Chen model and the Pitzer model give the largest deviation. In addition, the equation of state is applied to predict mean ionic activity coefficients at other temperatures by using the ion-ion interaction parameters at 298.15 K. The results show that the temperature dependence of the parameters is smaller than other four models.
    The Two-channel Model for Fast Fluidization
    Bai Dingrong, Jin Yong, Yu Zhiqing and Yao Wenhu (Department of Chemical Engineering, Tsinghua University, Beijing)
    1990, 41(1):  10-18. 
    Abstract ( 497 )   PDF (394KB) ( 217 )  
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    A new model of gas solid flow pattern for fast fluidization has been developed based on laboratory investigation and related literature. With regard to the axial and radial distributions of solid density and the internal particle circulation, this new mathematical model for fast fluidization is superior in clear physical concept and fewer parameters. All the model parameters are correlated by using experimental results from different investigators. These empirical correlations may be used in predicting the voidage distribution for fast fluidization as well as in interpreting the dynamics of the solid particles.
    Mathematical Modelling of Density Fluctuation and Its Application in Combustion
    Zheng Chuguang, Yu Dajiang and Mi Jianchun (Huazhong University of Science and Technology, Wuhan)
    1990, 41(1):  19-28. 
    Abstract ( 562 )   PDF (361KB) ( 172 )  
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    The density fluctuation correlation terms are introduced into modelling of a turbulent flame. A mathematical simulation of the density-scalar parameters fluctuation correlation terms (ρφ) is given in the calculation of combustion. The two transport equations for the density-velocity fluctuation correlation terms (pu and pv) are derived to solve the turbulence characteristics of a homogeneous gas flame and a heterogeneous pulverized coal flame. A further study has been made of the mutually interacting turbulent fluctuation and combustion process.
    Study on the Effect of Wall Slip for Sesbania Gum Flowing Through Capillary Tubes and Porous Media
    Han Yajun and Jiang Tiqian (East China Institute of Chemical Technology, Shanghai)
    1990, 41(1):  29-36. 
    Abstract ( 459 )   PDF (453KB) ( 94 )  
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    The flow behavior of Sesbania gum fracturing fluid through capillary tubes and porous media was studied experimentally. The gum exhibited yield values and power law behavior described by Herschel-Bulkley model both in capillary tubes and porous media. The flow was accompanied by significant positive slip effects in capillary tubes, whereas negative slip effects in porous media, under moderate shear rates. In the absence of apparent slip effects, the capillary-Herschel-Bulkley(C. H. B. ) model developed in this paper predicted the superficial velocities in the porous media with an average error of less than 10%. This provides a direct verification of the applicability of the C. H. B. model to the flow behavior of Sesbania gum in a limited range without considering "anomalous" wall effects.
    A Study on the Active Components of Iron-Molybdenum Oxide Catalysts Used in Ammoxidation of Methanol for HCN Syntheses
    Wang Yufu, Jia Shuxian, Wu Yanan and Wu Yue (Changchun Institute of Ap lied Chemistry, Academia Sinica, Changchun)
    1990, 41(1):  37-42. 
    Abstract ( 738 )   PDF (249KB) ( 192 )  
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    The active components of a series of Iron-Molybdenum oxide catalysts andtheir correlations with catalytic activity in ammoxidation of methanol were investigated by X-Ray diffraction, IR, Mossbauer, ESR and ESCA techniques. X-Ray diffraction and IR studies indicated that Fe and Mo ions were present as Fe2(MoO4)3, MoO3 and α-Fe2O3 in the catalysts. The plots of the relative content of Fe2(MoO4)3 and activity versus Fe/Mo showed corresponding peak shapes. Mossbauer, ESR and ESCA analysis showed that Fe existed in Fe3+ states at two different sites, one with octahedral coordination in Fe2(MoO4)3, the other with imperfect coordination in Fe2O3,xMoO3 where x<3. The former may be the basic active component, performing the function of selective oxidation together with the latter.
    Separation of Tungsten and Phosphorus by Solvent Extraction with Petroleum Sulfoxide
    Li Daren and Su Yuanfu (Chemical Engineering Research Centre, East China Institute of Chemical Technology, Shanghai)
    1990, 41(1):  43-49. 
    Abstract ( 536 )   PDF (286KB) ( 224 )  
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    Decomposition of tungsten ore concentrate is usually carried out by alkaline process and the intermediate product is crude sodium tungstate. It contains many impurities among which phosphorus is one of the most harmful elements. By using a solvent consisting of petroleum sulfoxide (PSO) and a diluent, the small amount of phosphorus can be removed almost completely in low acidic solution, i. e. at pH = 2.5 by countercurrent-multistage extraction. The extraction species is most likely H3PW12O40·PSO.
    Heat-Mass Resistance Factor Method for theComputation of Multicomponent Condensationwith Noncondensates
    Wu Yunying and Kan Hwaixin (Department of Chemical Engineering, Tianjin University, Tianjin)
    1990, 41(1):  50-57. 
    Abstract ( 586 )   PDF (312KB) ( 154 )  
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    Existing methods of designing heat exchangers for the condensation ofmulticomponent mixtures are of two basic kinds: equilibrium methods and non-equilibrium methods. Equilibrium methods not well-grounded in principle. The second methods are exact but they are too time consuming even in a single computation and very tedious for the design of a multichannel plate-fin exchanger. This paper is to present a total heat flux equation consisting of a heat-mass resistance factor correlated from a set of experimantal data. This is as simple as the equilibrium methods but still retain the non-equilibrium nature of the problem which signifies the condition of vapor and condensate in the condenser. The results are shown to be better than those from any approximate methods.
    A New Molecular Thermodynamic Model and Its Applications (l)A New Analytic Equation for Molecular Radial Distribution Function and Its Verification
    Li Jiding, Li Yigui, Lu Jiufang and Teng Teng (Department of Chemical Engineering, Tsinghua University, Beijing)
    1990, 41(1):  58-65. 
    Abstract ( 587 )   PDF (347KB) ( 243 )  
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    In this paper an analytic equation for the molecular radial distribution function of liquid solutions is proposed on the basis of the properties of liquid solution, the experimental phenomena, statistical thermodynamics and some similarity between total relation function and damping oscillation. The molecular radial distribution functions for pure Lennard-Jones fluid and for liquid argon calculated by the equation are compared with the computer simulation data and the experimental data with good agreement. Excess mixing enthalpy for several binary liquid mixtures calculated by the new model are also compared with the predictions of other theories and with experimental data.
    A New Molecular Thermodynamic Model and Its Applications (Ⅱ)The Application to Metal Solvent Systems
    Li Jiding, Li Yigui, Lu Jiufang and Teng Teng (Department of Chemical Engineering, Tsinghua University, Beijing)
    1990, 41(1):  66-73. 
    Abstract ( 455 )   PDF (363KB) ( 200 )  
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    Combining the analytic equation for molecular radial distribution function proposed in paper( I ) with Flory-Huggins equation, the molecularthermodynamic model for a non-electrolyte solution is established and is applied to the complicated metal solvent extraction systems, in which Co or Cu as well as Co and Cu are extracted by DEHPA. The activity coefficients for all components in the above systems and the thermodynamic equilibrium constants tor the extraction reactions are predicted by the model with the help of the experimental data from three binary systems. The predicted results are in good agreement with the experimental data.
    Gel-Extraction for Protein Concentration and Process Optimization
    Wang Shichang, Xie Lixin, Jin Lei and Yu Guocong(K. T. Yu) (Chemical Engineering Research Center, Tianjin University, Tianjin)
    1990, 41(1):  74-80. 
    Abstract ( 510 )   PDF (296KB) ( 142 )  
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    The polymer gels of H-SPAM, PAA-Na and S-PAA-Na can swell in water and collapse suddenly at a given pH, with the water released. By using them as extractants, a new process for protein concentration has been developed. The properties of acid-sensitive gel, the influences of ions, solute concentration and gel size on the performance of gel-extraction were studied experi-mentally.Optimization of the acid-sensitive gel-extraction process with complex method has been developed on the basis of regression oi experimental data.
    Solubility of Phenol in Subcritical and Supercritical Carbon Dioxide
    Yu Enping, Zhu Meiwen and Fang Zhirong (Department of Chemical Engineering Beijing Institute of Chemical Technology, Beijing)
    1990, 41(1):  81-86. 
    Abstract ( 570 )   PDF (287KB) ( 146 )  
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    An one-pass flow system was used to measure the equilibrium solubilities of phenol(solid) in sub critical and supercritical CO2. The temperatures covered were in the range of 303-312K, and the pressures in the range of 8.5-50MPa. The experiment data were correlated by the S. R. K. and P. R. equations of state, and a very good agreement was obtianed.
    A Study of Spray Falling Film Boilng on Horizontal Mechanically Made Porous Surface Tubes
    Wang Guoqing, Tan Yingke, Wang Shiping and Cui Naiying (Chemical Engineering Research Institute, South China University of Technology, Guangzhou)
    1990, 41(1):  87-93. 
    Abstract ( 545 )   PDF (338KB) ( 227 )  
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    The present paper describes a study of spray falling film boiling on horizontal mechanically made porous surface tubes (JK-1 tubes). R-113 was used as the working fluid. The results indicated that there was a 11-80% increase of heat transfer coefficients for falling film boiling on the enhanced lubes in comparison with those of their pool boiling; and there was a 2.7-6.2 times increase in comparison with those for falling film boiling on a smooth tube. Based on the analysis, a correlation was proposed which could predict spray falling film boiling heat transfer coefficients for horizontal mechanically made porous surface tubes within a relative deviation of±8%.
    Multiphase Diffusion Mass-Transfer in Shell-Core Type Ion Exchanger
    Ma Yongli and Yang Hongxiu (Dept. of Materials Science, Lanzhou University, Lanzhou)
    1990, 41(1):  94-102. 
    Abstract ( 495 )   PDF (409KB) ( 120 )  
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    A physic-mathematical model is presented for multiphase diffusion mass-transfer in shell-core type ion exchanger. Both liquid film diffusion and inner-particle diffusion, which control the mass-transfer rate, are unsteady-state processes in quasihomogeneous phase. An equation of exchange fraction is. systematically derived. The basic laws of kinetics offer a theoretical basis for selecting optimization parameters. This equation can also be used to determine inner-particle diffusion coefficient and liquid film thickness.
    Non-ideal Multi-component Dynamic Model of Distillation Tower
    Yang Jian, Qian Jixin and Zhou Chunhui (Chemical Engineering Department, Zhejiang University, Hangzhou)
    1990, 41(1):  103-110. 
    Abstract ( 572 )   PDF (385KB) ( 261 )  
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    In this paper, a new dynamic distillation model(simulation algorithm) has been derived. Because of the use of linear algebraic equations derived from enthalpy balances to solve for the ascending vapor quantity, and the use of differential equations for all other variables, the divergent problem caused by the iteration of nonlinear equations for the attainment of bubble point or dew point temperatures can be avoided. The large dynamic model of a dehex-anizer of seventy plates and six components(differential equation with an order of more than six hundred) has been calculated successfully by an integration method for solving stiff ordinary differential equations-numerical small parameter method. The conspicuous advantage of the method is no need of Jacobian matrix calculation and its inversion.
    Automatic Measurement of the Size and Distribution of Gas Bubble and Liquid Drop in Two-phase Flow
    Gao Dunyue, Jiang Hong Yu Bing, Deng Xiu and Shi Yajun (Research Centre of Automatic Control,Bast China Institute of Chemical Technology, Shanghai) (Chemical Engineering Research Centre, East China Institute of Chemical Technology, Shanghai)
    1990, 41(1):  111-117. 
    Abstract ( 763 )   PDF (287KB) ( 397 )  
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    A microcomputer aided system with the use of a photoelectric capillary probe is used for on-line automatic measurment of gas bubble, liquid drop and foam size distribution in two-phase flow. The experimental results were calibrated for the pressure in the capillary probe. The system works well with the advantage of high accuracy, high speed, and simple operation. In this paper, the principles of the technique are put forward, the hardware disposition and the software for sampling and handling data in the microcomputer aided system are introduced. Finally, the method of calibration and some results of measurement are presented.
    Diffusion of Solvent Vapor in a Foreign Gas Bubble
    Yang Ningsheng, Shen Ziqiu and Ma Yingni (Dalian University of Technology, Dalain)
    1990, 41(1):  118-121. 
    Abstract ( 554 )   PDF (203KB) ( 141 )  
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    The diffusion process of liquid vapor in a gas bubble has been investigated numerically. With the assumptions of (1) spherical gas bubble; (2) constant temperature at gas-liquid interface; (3) no circulation inside the bubble, the mass transfer equation is developed as: Initial conditions C(r, 0)=C0 Boundary conditions C(R, t)=Cf It is also assumed that the pressure within the bubble is in equilibrium with ambient pressure during the bubble growth A stepwise approach has been proposed to solve the moving boundary problem. The results show that Dt/R02 and Ps/P are the main factors for the dynamics of bubble growth. Generally speaking, increasing liquid temperature Tc and diffusitivity D, or reducing the ambient pressure P and initial bubble radius R0 favor the mass transfer, especially as PS/P→1, the enhancement of mass transfer is more obvious.
    A Study on Pseudo-static Method for VLE Determination
    Zhou Xingfeng, Ni Liang and Han Shijun (Department of Chemistry, Zhe Jiang University, Hangzhou)
    1990, 41(1):  122-126. 
    Abstract ( 612 )   PDF (192KB) ( 246 )  
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    Based on the error equation of ebulliometry: the t-xo line measured by a ebulliometer has the best approximation of the bubble-point line t-x when the circulation is set on the pseudo-static state where the condensate reflux diminishes to zero (r = 0). In this paper, the principle and realization of the method are further studied from different points of view, and three newly designed ebulliometers with pump stirrer are shown. The functions of the new ebulliometers and the reliability of the method are tested through experiments done in different concentration ranges and in different ways.