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Table of Content
25 June 1997, Volume 48 Issue 3
    化工学报
    SOLUBILITIES AND MICRONIZATION OF ALUMINUM ISOPROPOXIDE IN SUPERCRITICAL PROPANE
    Wang Zhaohui, Dong Junhang, Xu Nanping and Shi Jun(Membrane Science and Technology Research Center, Nanjing University of Chemical Technology, Nanjing 210009)
    1997, 48(3):  257-263. 
    Abstract ( 673 )   PDF (429KB) ( 263 )  
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    Solubilities of aluminum isopropoxide in supercritical propane were determined by weighing method using a flow apparatus at temperatures of 388 K and 403 K and at pressures from 21.5MPa to 30.5MPa. The experimental data were correlated satisfactorily by two empirical equations correlating to the density of supercritical propane. Formation of aluminum isopropoxide particles by the rapid expansion of supercritical fluid solution (RESS) technique was performed at two extraction temperatures, 388 K and 403 K. No significant differences of the morphology of product particles were observed under the different extraction conditions because of the small change of the solute concentration.
    NUMERICAL SIMULATION OF POLYMERIC FLOW BASED ON MOLECULAR MODELS
    Fang Jiannong, Fan Yurun, Dai Zhiqian and Fan Xijun(Department of Mechanics, Zhejiang University, Hangzhou 310027)
    1997, 48(3):  264-269. 
    Abstract ( 543 )   PDF (316KB) ( 341 )  
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    A new method for numerical calculation of polymeric flow based on simulation of molecular models of polymers is presented. The approach directly combines streamline finite element method with stochastic simulation of molecular models and thus obviates the need for a constitutive equation to describe the fluid. The problem considered for testing the method is the two - dimensconal steady flow of an Oldroyd - B fluid past a circular cylinder between two parallel plates. A comparison is made between the numerical results obtained using the new approach and those obtained using the closed- form constitutive equation of the Oldroyd -B model.
    PREDICTION OF BREAKTHROUGH CURVES IN FIXED-BED ADSORBERS OF ACTIVATED CARBON FIBER (Ⅰ) EXACT SOLUTION AND APPROXIMATE SOLUTIONS
    Xiu Guohua.Li Ping and Jin Ge(Department of Chemical Engineering, Shenyang Institute of Chemical Technology, Shenyang 110021)
    1997, 48(3):  270-277. 
    Abstract ( 810 )   PDF (333KB) ( 231 )  
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    For the linear adsorption isotherm, an exact solution for the prediction of breakthrough curves (step response) in fixed-bed adsorbers packed with activated carbon fiber is obtained, that takes into account axial dispersion, intrefiber diffusion and external convective mass transfer resistance. The effects of model parameters on the breakthrough curves are discussed. Two kinds of approximate solutions, i. e. , the parabolic profile approximation and the quasi -log normal distribution approximation are also obtained. The results show that the two approximate solutions are in good agreement with the exact solution over a wide range of parameters of Bi, Pe and the bed length parameter θ. The quasi -log normal distribution approximate solutionis a simple, rapid approximate solution for the calculation of breakthrough curves.
    PREDICTION OF BREAKTHROUGH CURVES IN FIXED-BED ADSORBERS OF ACTIVATED CARBON FIBER (Ⅱ) EXPERIMENTS AND MODELS TEST
    Li Ping, Xiu Guohua and Jin Ge(Department of Chemical Engineering, Shenyang Institute of Chemical Technology, Shenyang 110021)
    1997, 48(3):  278-283. 
    Abstract ( 934 )   PDF (304KB) ( 135 )  
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    The exact solution and the two approximate solutions for the linear adsorption proposed in paper (Ⅰ) was used to simulate the breakthrough data of adsorption of Pb2 + on activated carbon fiber in a fixed - bed with the adsorption equilibrium constant determined from a separate experiment. The results showed that the two approximate solutions were in reasonable agreement with the exact solution; the quasi - log normal distribution approximation is a simple, rapid approximate solution for the calculation; the effect of the axial dispersion on the breakthrough curves is appreciable, and can not be neglected; the equilibrium constant can be easily evaluated by simulating the breakthrough data of adsorption.
    COMPUTATION EQUATION OF CROSS-TERM COEFFICIENTS IN MULTICOMPONENT DIFFUSION
    Ma Guoyu(Department of Mathematics - Physics, Beijing University of Chemical Technology, Beijing 100029)Zhou You(Department of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029)Kun Soo Chang( Pohang University of Science and Technology, Pohang, S. Korea)
    1997, 48(3):  284-293. 
    Abstract ( 605 )   PDF (355KB) ( 154 )  
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    A theoretical computation equation of Ficks law in matrix form is given for predicting the cross - term coefficients in binary diffusion, and the results are extended to 3 - component and multicomponent diffusion systems. Finally, a generalized equation of Ficks law is obtained.
    THE EFFECT OF INITIAL SATURATION ON HEAT AND MASS TRANSFER DURING MICROWAVE FREEZE DRYING
    Wang Zhaohui and Shi Mingheng(Department of Power Engineering , Southeast University, Nanjing 210018 )
    1997, 48(3):  294-299. 
    Abstract ( 818 )   PDF (313KB) ( 107 )  
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    Microwave freeze drying experiments are carried out with unsaturated raw beef. The analysis of heat and mass transfer on experimental results shows that the drying time is approximately proportional to initial saturation of porous media. As compared with the calculated results of sublimation interface model, in which sublimation is assumed to take place at an interface, the sublimation - condensation model agrees better with experimental results than those of sublimation interface model. This proves that a sublimation-condensation region does exist during microwave freeze drying of unsaturated porous media.
    KINETIC MODELS FOR ARACHIDONIC ACID FERMENTATION PROCESS
    Bao Shixiang, Zhu Fake, Lin Weitie and Yao Ruhua(Department of Biochemical Engineering, South China University of Technology, Guangzhou 510641 )
    1997, 48(3):  300-303. 
    Abstract ( 559 )   PDF (185KB) ( 111 )  
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    The fermentation process for producing arachidonic acid by Mortierella was analyzed. The kinetic models of cell growth and lipid formation were established, and the model parameters were regressed with the experimental data. The simulated curves by the models were in good agreement with the experimental data.
    MODELING AND SIMULATION OF THERMAL BULK POLYMERIZATION OF STYRENE IN TUBULAR REACTOR
    Xie Fangning, Pan Qinmin and Pan Zuren(Institute of Polymer Science and Engineering , Zhejiang University , Hangzhou 310027)
    1997, 48(3):  304-314. 
    Abstract ( 601 )   PDF (426KB) ( 105 )  
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    A model for styrene thermal polymerization process in tubular reactor has been developed starting from basic transport equation without adjustable parameters. Radical and axial changes in velocity and temperature were taken into consideration in this model. Various factors that affect monomer conversion and product quality such as dimensions of reactor, wall temperature, inlet temperature and inlet mass flow, were studied by computational simulation based on this model. The result show that reactor length, reactor diameter, wall temperature and inlet mass flow have significant effects on monomer conversion and quality of product. Whereas inlet temperature effect is much weaker.
    STUDIES ON THE INITIAL KINETICS OF THE POLYMERIZATION OF DICYCLOPENTADIENE
    Mi Zhengtao(Department of Chemical Engineering, Tianjin University, Tianjin 300072)Liu Tingbin(Beijing Designing Institute , SINOPEC, Beijing 100011)
    1997, 48(3):  315-319. 
    Abstract ( 616 )   PDF (209KB) ( 138 )  
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    In this paper, the initial kinetics of the polymerization from dicyclopentadiene (DCPD) to polydicyclopentadiene(PDCPD) has been studied . The polymerization of DCPD is initiated by molybdenum pentachloride (MoCl5) and diethylaluminun chloride (Et2AlCl). The kinetics data under different conditions are measured by dilatometer. According to the chain mechanism of ring - opening polymerization, initiated by metal - carbene active centers, the intrinsic kinetics equation is derived by poly - parameter nonlinear optimization (Powell program). The activity energy is 32.022 ×103 J·mol-1.
    STUDY ON THE KINETICS OF ANIONIC POLYMERIZATION OF ISOPRENE INITIATED BY MODIFIED NAPHTHALENE - LITHIUM
    Han Bingyong and Jin Guantai( College of Material Science and Engineering, Beijing University of Chemical Technology, Beijing 100029)
    1997, 48(3):  320-328. 
    Abstract ( 834 )   PDF (376KB) ( 123 )  
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    The kinetics of anionic polymerization of isoprene initiated by organodilithium in cyclo-hexane , in which a little THF was included and the molar ratio ( R) of THF to Li was equal to 1, was investigated. The propagation reaction rate (Rp) was first order with respect to monomer concentration. However the rate order (β) relative to the concentration of active species was less than 1 and could be expressed as:β= 0.3318 + 5.3240 × 10-3 t . The conception of association and monomolecular active chain ends was replaced by the conception of association and free states of the active chain ends and a kinetic equation of isoprene polymerization initiated by organodilithium was derived as follows[C0]/k=4/(k2k12kp4)k3+2/(K1kp2)k+1/(kp)According to the equation and taking use of the concentration of initiator [ C0 ] and quasi -reaction rate constant (k),the values of real propagation reaction rate constant (kp),equilib -rium constants of tetra - association and di - association states K2 and equilibrium constant of di - association and free states K1 were obtained. Based on equilibrium constants (K1, K2) the dissociation energies,have been calculated ΔH1 ,ΔH2,and the concentrations of tetra - association state,di - association state and free state have been deduced respectively. The activation energies of kp and kap were shown to be Ep = 64.306 kJ·mol-1、Eap = 88.364 kJ·mol-1.
    EFFECTS OF FLUID PROPERTIES ON SHELL -SIDE TWO IMMISCIBLE COMPONENTS TWO-PHASE FLOW PATTERNS AND AN OVERALL FLOW PATTERN MAP
    Huang Xinghua, Wang Qijie and Gan Taixiang(Department of Power Machinery Engineering , Shanghai Institute of Electric Power, Shanghai 200090)
    1997, 48(3):  329-335. 
    Abstract ( 614 )   PDF (333KB) ( 116 )  
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    Based on the previous study of air -water and air -0# diesel oil systems, a futher study of the effects of fluid properties on shell -side two -phase flow pattern transitions with air -30 % glycerine water solution system is presented. The experimental results showed that liquid viscosity and surface tension have significant effects on the transition to annular flow and stratified -annular flow, but little effect on the transition to bubble flow. Liquid viscosity has no effect on the transition to intermittent flow, while surface tension has a slight effect. On the basis of physical concepts, an overall flow pattern map is constructed, which based on the data of air-water, air-0# diesel oil and air-30% glycerine water solution two-phase flow systems.
    MACRO-MIXING PROCESS INVESTIGATION FOR JET-ENTRAINED GASIFIER (Ⅲ) PROCESS ANALYSIS AND SIMULATION
    Wang Fuchen, Wu Tao, Yu Jianguo,Gong Xin and Yu Zunhong(College of Resource and Environmental Engineering , East China University of Science and Technology, Shanghai 200237)
    1997, 48(3):  336-346. 
    Abstract ( 567 )   PDF (549KB) ( 272 )  
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    Process analysis of jet entrained bed gasification system is made and a mechanism model for gasification process is proposed in this paper. Then a mathematic model is presented for jet entrained bed gasification. Simulation of industrial residual -oil gasifier and coal -water slurry gasifier is made and the effects of process conditions on gasification are predicted by using the model.
    NONLINEAR INTERNAL MODEL CONTROL STRATEGY FOR FUZZY MODELS AND ITS APPLICATION ON pH NEUTRALIZATION PROCESS CONTROL
    Wang Yin, Rong Gang and Jin Xiaoming(Institute of Industrial Process Control, Zhejiang University , Hangzhou 310027)
    1997, 48(3):  347-353. 
    Abstract ( 549 )   PDF (300KB) ( 219 )  
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    pH neutralization process is a highly nonlinear process and its control problem has been in the spotlight in process control research. In this paper, a nonlinear internal model control strategy based on fuzzy models (FNIMC) is proposed for pH neutralization process control problems. The fuzzy model is identified from input/output data using fuzzy inference network. The FNIMC controller consists of a model inverse controller and a robustness filter with a single tuning parameter. Simulation result for this highly nonlinear process demonstrates the ability of the new strategy to outperform nonlinear PID controller.
    EFFECT OF PRECURSOR PHASE COMPOSITION OF AMMONIA SYNTHESIS CATALYST ON REDUCTION PERFORMANCE
    Liu Huazhang and Li Xiaonian(Institute of Catalysis , Zhejiang University of Technology, Zhejiang Province Key Laboratory of Heterogeneous Catalysis , Hangzhou 310014)
    1997, 48(3):  354-362. 
    Abstract ( 586 )   PDF (465KB) ( 126 )  
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    The effect of different original composition of iron oxide in the precursor on the reduction performance of ammonia synthesis catalyst was studied by thermal analysis. The precursor phase composition of the catalyst produces an effect on reduction performance, which is similar with the effect on activity. In the case of two phase coexistence in the precursor, the reduction process of catalyst is divided into sequential stages with respect to phase, which obeys the competitive reduction mechanism. It results in slower reduction rate,higher reduction temperature and decreasing catalyst activity. The reduction performance of ammonia synthesis catalyst is consistent with its activity,the easier the catalyst reduction,the higher is the activity. The experimental results indicate that Fe1-xO based catalyst has the fastest reduction rate, the lowest reduction temperature and the highest activity among all the fused iron catalyst for ammonia synthesis.
    NUMERICAL SIMULATION OF FILLING FLOW OF POLYMER MELT IN INJECTION MOLDING
    Lin Lanfen(Department of computer , Zhejiang University, Hangzhou 310027 )Ma Zeen(Department of aircraft manufacturing Engineering Northwestern Polytechnolagy University, Xian 710072)
    1997, 48(3):  363-368. 
    Abstract ( 704 )   PDF (316KB) ( 145 )  
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    Injection molding is one of the most important polymer processing operations. The results from numerical simulation of this process provide valuable information in designing part/ mold or choosing process parameters. The flow simulation is based on a hybrid finite-element/ finite-difference numerical solution of the generalized Hele-Shaw flow of a non - Newtonian fluid under non - isothermal condition. A unified expression in terms of flow rate is set up for both entrance and interior nodes. In advancing the melt front , the commonly used method of determining time step is modified. Two examples are given to show the validity of the numerical method.
    CLIMBING FILM EVAPORATION IN A TRANSPARENT TUBE PUMPED BY STEAM INJECTION
    Guo Xueyan, Li Li and Xia Qing( Department of Chemical Engineering, Tianjin University, Tianjin 3000072)Lin Zaiqi and Lin Jifang( Chemical Engineering Research Insitute, Dalian University of Technology, Dalian 1160112)
    1997, 48(3):  369-373. 
    Abstract ( 528 )   PDF (234KB) ( 102 )  
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    Two - phase flow and evaporation heat transfer in climbing film flow pumped by steam nozzle were studied experimentally in a transparent electrically- heated quartz tube. The effects of heat flux and flow rate of injected steam on flow and heat transfer were investigated. Annular flow was found to be the dominant pattern in almost all the experimental situations. The perfo-mance of heat transfer was satisfactory.
    PRESSURE CALCULATION OF COPOLYMERIZATION SYSTEMS INVOLVING CO_2
    Chen Liban, Yang Shuying, He Shujie, Zhang Wenjun and Yu Aifang(Guangzhou Institute of Chemistry, Academia Sinica, Guangzhou 510650)
    1997, 48(3):  374-377. 
    Abstract ( 612 )   PDF (188KB) ( 132 )  
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    For the multi - phase systems involving CO2, the pressure p can be estimated from the temperature, the weight of CO2, and the volume not occupied by materials other than CO2. An empirical equation is introduced, by which the standard deviation for p calculation is 10.4 % for 11 systems. The accuracy can be improved by considering different solubility of CO2 in various liquid components. By this means, the pressure p can be determined with a standard deviation of 5.39 % . Thus the vapor- liquid equilibrium and kinetic parameters can be obtained without experimental measurements. Further, the copolymerization process of CO2 and propylene oxide can be simulated satisfactorily.
    SULFONATION OF TOLUENE BY GASEOUS SULPHUR TRIOXIDE IN A JET LOOP REACTOR
    Wang Baohe, Wu Jinchuan, Zhang Deli , Yuan Jitang and Liu Bangfu(Research and Development Center for Petrochemical Technology, Tianjin University, Tianjin 300072)
    1997, 48(3):  378-381. 
    Abstract ( 893 )   PDF (177KB) ( 162 )  
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    Continuous sulphonation of toluene by gaseous sulphur trioxide has been studied in a pilot - scale jet loop reactor with a external heat exchanger. The experimental results indicate that the isomer distribution of toluene sulphonic acids is unaffected by other operating conditions under a given temperature. The content of meta isomer in the mixture of isomers is Jess than 1.2% .whereas that of para isomer is around 85% under the reaction temperature of 10 ℃ and conversion of toluene in the range of 30% - 40%.
    EXTENDING WONG - SANDLER TYPE MIXING RULE TO GENERALIZED MULTIPARAMETER CUBIC EQUATIONS OF STATE
    Yang Tao, Chen Guangjin, Yan Wei and Guo Tianmin(Reservoir Fluid High Pressure Phase Behavior and Property Research Laboratory, University of Petroleum , Beijing 102200)
    1997, 48(3):  382-388. 
    Abstract ( 683 )   PDF (249KB) ( 156 )  
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    The original Wong - Sandier type mixing rule can only be used for two parameters cubic equation of state. By developing the excess Helmholtz free energy under a high pressure reference state and introducing suitable corresponding parameters which reflect mixing properties, Wong - Sandier type mixing rules were extended to generalized multiparameter cubic equations of state. In this work, the Modified Kumar- Starling cubic equation of state was chosen as a working equation. The method of introducing Wong - Sandier type mixing rule to generalized cubic equations of state is of great significance for extending the applications of Wong - Sandier type mixing rule where multiparameter cubic equations of state are used as working equations.