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Table of Content
25 February 1996, Volume 47 Issue 1
    化工学报
    PREDICTION OF ADSORPTION EQUILIBRIA OF MULTICOMPONENT LIQUID MIXTURE ON SOLIDS BY LATTICE MODEL
    Han Zhenwei;Zhou Ming;Yu Guocong(K.T.Yu)(Chemical Engineering Research Center,Tinajin University,Tianjin 300072)
    1996, 47(1):  1-7. 
    Abstract ( 485 )   PDF (338KB) ( 146 )  
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    A new method for the prediction of adsorption equilibria of a multicomponent liquid mixture on heterogeneous solid surfaces is proposed on the basis of the lattice model.Equations for adsorbed-phase activity coefficients are obtained by taking the energetic heterogeneity effects of solid surfaces into account.Only the binary parameters are needed for the calculation of the equilibrium of multicomponent adsorption.The adsorption equilibria of benzene-toluene-cyclohexane on silica gel,benzene-ethanol-cyclohexane on activated carbon and benzene-ethyl acetate-cyclohexane on activated carbon are calculated by the method and the theoretical results agree well with the experimental data.
    MATHEMATICAL MODEL OF CLASSIFICATION EFFICIENCY IN SPRAY GRANULATOR-DRYER
    Wang Hualin;Wu Dongdi;Chen Wenmet(Research Institute of Process Equipment and Pressure Vessels,East China University of Science and Techology,Shanghai 200237)(Department of Chemical Engineering,Sichuan United University,Chengdu 610065)
    1996, 47(1):  8-15. 
    Abstract ( 540 )   PDF (367KB) ( 209 )  
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    The spray granulator dryer has a mechanism of speed-gradient classifcation.A mathematical model of classification efficiency was proposed.The necessity of a drumscreen at the end of the cone was discussed.
    EFFECT OF VARIABLE POROSITY NEAR THE WALL ON FREEZING HEAT TRANSFER IN LIQUID-SATURATED POROUS MEIDIA
    Ma Ji;Wang Buxuan(Tsinghua University,beijing 100084)
    1996, 47(1):  16-21. 
    Abstract ( 546 )   PDF (271KB) ( 205 )  
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    The one-dimensional conduction-dominated freezing heat transfer problem has been numerically solved using the implicit enthalpy method with the node-jump technique.The effect of variable porosity near the wall on freezing heat transfer rate is presented and discussed for the first time.The results for glass bead saturated with water have shown that during the precooling period,there is no obvious effect of variable porosity on the freezing process,while during the freezing period.the variable porosity will enhance freezing heat transfer and obviously increase the freezing depth.
    EXPERIMENTAL INVESTIGATION ON THE HEAT TRANSFER CHARACTERISTICS BETWEEN GAS AND SOLIDS IN A CENTRIFUGAL FLUIDIZED BED
    Hao Yingli;Shi Mingheng(Southeast University,Nanjing 210096)
    1996, 47(1):  22-28. 
    Abstract ( 498 )   PDF (368KB) ( 109 )  
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    An experimental study on the heat transfer characteristics between gas and solid phase in a centrifugal fluidized bed was performed.Glass bead,sand and alumina bead were used as bed material in the heat transfer test.The gas temperatures at the inlet and outlet and the bed temperature were measured with thermocouples.The influences of bed thickness,particle diameter,the characteristics of bed material,the rotating speed of the bed and gas superficial velocity on the heat transfer between gas and Particles were examined.An empirical correlation which can be used to calculate the gas-solid heat transfer coefficient in the centrifugal fluidized bed was obtained.
    KINETICS OF RADICAL POLYMERIZATION IN A STARVED FEED REACTOR(Ⅰ)── DISCUSSION ON LONG-CHAIN ASSUMPTION
    Cao Guiping;Zhu Zhongnan(State Key Lab of Chemical Engineering,East China University of Science&Technology,Shanghai 200237)
    1996, 47(1):  29-34. 
    Abstract ( 571 )   PDF (267KB) ( 118 )  
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    It is always assumed that polymerization rate is equal to chain propagation rate while setting up kinetics model of radical polymerization.In the assumption the rate of monomer consumption due to the reaction of primary radicals with monomer is very small and can be ignored,and that is the long-chain assumption.This paper deals with the as sumption in detail.The calculated results indicates that in the case of high temperature and/or high initiator concentration,especially in a starved feed reactor,the long-chain assumption needs correcting so that a more accurate kinetics model of radical polymerization can be set up.
    KINETICS OF RADICAL POLYMERIZATION IN A STARVED FEED REACTOR (Ⅱ)──KINETICS OF METHYLMETHACRYLATE POLYMERIZATION
    Cao Guiping;Zhu Zhongnan;Le Huihui;Zhang Minghua;Shen Jinghui(State Key Lab of Chemical Engineering,East China University of Science&Technology,Shanghai 200237)
    1996, 47(1):  35-41. 
    Abstract ( 516 )   PDF (330KB) ( 125 )  
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    The kinetics of methylmethacrylate radical polymerization in a continuous phase semi-batch polymerization reactor is studied.In the reactor,monomer and initiator are fed at a constant,small rate into a fixed amount of solvent.This type of reactor is useful in the production of a low molecular weight polymer which can be used to make coating and adhesive formulations.The kinetics model incorporates the rate of monomer consumption due to the reaction of Primary radicals with monomer,the rate of PMMA depolymerization at high temperature and the termination rate constant dependent on the gel effect.The model constants are regressed with the help of experimental data.
    XRD STUDIES AND ELECTROCHEMICAL SURFACE SPECTRUM OF RuO_2-SnO_2 MIXED METAL OXIDES ELECTRODE
    Chen Yanxi;Xia Xiaoxia;Chen Yanying;Chen Jiang(Department Of Applied Chemistry,Tianjin University,Tianjin 300072)
    1996, 47(1):  42-47. 
    Abstract ( 464 )   PDF (310KB) ( 118 )  
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    The phase structure and lattice constants of RuO_2-SnO_2 mixed metal oxides electrode was investigated by XRD.It was found that mixed oxides system formed a solid solution of RuO_2- SnO_2 with a rutile- type structure,but it had a smaller crystalline size and more compact than the RuO_2-TiO_2 system. Cyclic voltammetry provided information about electrochemically active surface area(q).The results indicated that for RuO- SnO_2 (associated with the external surface)was less and (associated with the internal surtface) was bigger than that of RuO_2-TiO_2. The enhancement of stability for Ru-Sn can be attributed to more compact oxide layer and the formation of a stable Ru-Sn compound.
    STUDY OF Ni-CO-P AMORPHOUS ALLOY ELECTRODEPOSITION AND ITS PROPERTIES
    Yao Suwei;Liu Bing;Guo Hetong;Takao Sugiyama(Department of Applied Chemistry,Tianjin Univerrsity,Tianjin 300072)(Sannoh Riken Co,Ltd,Japan)
    1996, 47(1):  48-52. 
    Abstract ( 689 )   PDF (225KB) ( 240 )  
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    It is not likely to obtain electrodeposited Ni-Co alloys with amorphous structure.The deposits become amorphous by adding element P.Electrodeposited Ni-Co-P alloys containing P less than 5% are solid solutions.The deposits containing 5%-19% P are amorphous,while deposits with P more than 19% show the structure of an intermetallic com-ound.Amorphous Ni-Co-P deposits high hardness,excellent wear resistance and good corrosion resistance in 3% NaCl solutions.
    MAGNETIC FLUIDIZATION OF-GROUP C POWDER(Ⅰ)──MECHANISM
    Zhu Qingshan;Li Hongzhong(Institute of chemical metallurgy,Academia,Sinica,Beijing 100080)
    1996, 47(1):  53-58. 
    Abstract ( 488 )   PDF (325KB) ( 273 )  
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    The fluidization mechanism of group C powder under an external magnetic field has been studied.Magnetic powders rearrange themselves to form the“structure of chain”with these chains being able to penetrate into bubble from the top and make bubble broken,which is the reason why magnetic field can improve fluidization quality of group C powder.A mathematical model is derived through the forces analysis of chains.Furthermore,a dimensionless number is developed to forecast the formation of magnetically condensed state in this paper.
    MAGNETIC FLUIDIZATION OF GROUP C POWDER EXPERIMENTAL STUDY(Ⅱ)──EXPERIMENTAL STUDY
    Zhu Qingshan;Li Hongzhong(Institute of chemical metallurgy,Academia Sinica,Beijing 100080)
    1996, 47(1):  59-64. 
    Abstract ( 454 )   PDF (307KB) ( 282 )  
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    The fluidization behavior of group C powder in an axial uniform magnetic field has been studied.Experiments demonstrate that channels and bubbles can be eliminated effectively.Two optica1 fiber probes are used to measure the size of bubble in the bed and the bubble size decreases with increasing magnetic field intensity and magnetic powder fraction.The length of"chain",obtained by using CA5300 board and modular system,is found to be strongly influenced by the magnetic field intensity.Experimental data are in agreement with that of calculated results from the mathematical model.
    INVESTIGATION ON THE SOLID STATE REDUCTION OF FLUORAPATITE
    Qiu Liyou;Liang Bin;Jiang Like(Department of Chemical Engineering,Chengdu University of Science and Technology,Chengdu 610065)
    1996, 47(1):  65-71. 
    Abstract ( 516 )   PDF (388KB) ( 243 )  
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    The reaction mechanism and rate-controlling step for the carbon reduction of fluorapatite were investigated with the shaped feeds of fluorapatite,silica(AR)and active carbon(reagent)Powders.The reaction mechanism is suggested as that 2C_a F_2 SiO_2 and Ca_3(PO_4)_2are formed in the defluorination between f1uorapatite and silica,and then the Ca_3(PO_4)_2 diffuses through the molten liquid onto the surface of carbon particle where it is reduced by carbon.The steps are The fluor is evolved in the form of SiF_4 at a higher silica-lime molar ratio.When the silica-lime molar ratio is rather lower,the fluor remains in the residue in the form of 2CaF_2·SiO_2.
    AZO-HYDRAZONE TAUTOMERISM OF 2-PHENYLAZO-1-NAPHTHOL DERIVATIVES
    Tian Yazhen;Wang Guijuan;Wu Zuwang(College of Chemical Engineering,dalian University of Technology,Dalian 116012)
    1996, 47(1):  72-76. 
    Abstract ( 487 )   PDF (220KB) ( 153 )  
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    Eleven 2-phenylazo-1-naphthol dyes have been synthesized,and the H,C NMR spectra are recorded.The electron effect of substituents on the benzene ring,and solvent pH effect on azo-hydrazone tautomerism,as well as the relationship between the molecular structure and the colour are discussed.
    SIMULTANEOUS OPTIMIZED SYNTHESIS FOR HEAT EXCHANGER NETWORKS──A IMPROVED MINLP TRANSSHIPMENT MODEL APPROACH
    Yuan Yi;Yin Hongcbao;Wang Xiaoyun;Shi Guangyan(School of Chemical Engineering,Dalian University of Technology,Dalian 116012)(Applied Mathematics departmet,dalian University of Technology,Dalian 116023)
    1996, 47(1):  77-84. 
    Abstract ( 593 )   PDF (424KB) ( 179 )  
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    In this paper,an improved mixed-integer nonlinear programming(MINLP)model is presented which can synthesize heat exchanger networks where utility cost,exchanger areas and selection of matches are optimized simultaneously.By the use of the stagewise superstructured transshipment model and concepts of endothermic and exothermic potentialities of the process streams,the proposed model eliminates the unreasonable assump tion on isothermal mixing for stream splits under the condition where all the constraints are linear.The optimal network can be obtained by solving only one MINLP problem.Examples are presented to illustrate that the proposed simultaneous synthesis model has more advantages than others.
    COALESCENCE OF A SMALL DROP ON A PLANE LIQUID-LIQUID INTERFACE
    Liu Shiping;Li Dougming(Departmet of Chemical Engineering,Tianjin University,Tiangjin 300072)
    1996, 47(1):  85-90. 
    Abstract ( 548 )   PDF (280KB) ( 184 )  
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    The coalescence process of a small drop on a plane liquid-liquid interface in pure liquid-liquid systems has been studied.A model for the dynamics of the thinning film was developed with the interfacial mobility taken into account.London-van der Waals force in thin liquid film was recognized.The model predicted the coalescence time,which is the time required for the thinning and rupture of the liquid film,given the radius of the drop and the required physical properties of a liquid-liquid system.The predicted result was in good agreement with previous experimental results.
    THE JET PENETRATION DEPTH IN A FLUIDIZED BED OF MULTI-COMPONENT PARTICLES
    Luo Guohua;Zhang Jiyu;Zhang Bijing(Institute of Coal Chemistry,Academia Sinica,Taiyuan 030001)
    1996, 47(1):  91-99. 
    Abstract ( 509 )   PDF (465KB) ( 140 )  
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    The jet penetration depth and gas velocity profiles were experimentally studied using a measurement system consisting of multi-Pitot-tube,mini-pressure transducer,and magnetic valves.It is found that the Potential core height of a jet for Geldarts B or D particles is much greater than that for Geldarts A particles and the jet penetration depth increases with the decrease of mean particle density and particle size for both monocomponent and binary mixtures.On the basis of the theoretical analysis,an semi-empirical equation including the modified Froude number and the Stokes number can be satisfactorily used to estimate the jet penetration depth in gas-solid jetted fluidized beds.
    THE CRYSTALLIZATION PROCESS FOR PENICILLIN G SALT
    Wang Jingkang;Zhang Mening;Wan Tao;Ping Zhicun;Han guian(Chemical Engineering Department,Tianjin University,Tianjin 300072)(Pharmacy Company of North Chian,Shijiazhuang 050011)
    1996, 47(1):  100-105. 
    Abstract ( 1206 )   PDF (317KB) ( 401 )  
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    In this paper,the vacuum evaporative crystallization process of β lactam antimicrobial pharmaceuticals is studied.The crystallization thermodynamic data,such as the phase equilibrium diagram and the metastable zone of pencillin G potassium are determined.Furthermore,the crystallization kinetic parameters for penicillin G potassium salt in n-butanolwater solution are measured by using an unsteady method.Therefore,the optimal operating time table for the crystallization process is established.
    DETERMINATION OF AZEOTROPES AT SUPERATMOSPHERIC PRESSURES FOR BINARY AND TERNARY SYSTEMS
    Yan Xinhuan;Wang Qi;Chen Genghua;Han Shijun(Department of Chemistry,Zhejiang University,Hangzhou 310027)
    1996, 47(1):  106-109. 
    Abstract ( 653 )   PDF (204KB) ( 251 )  
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    The azeotropic data were determined for four ternary systems of ethanol-acetone-n-hexane,cyclohexane-ethyl acetate-isopropanol,cyclohexane-ethyl acetate-bu-tanone,cyclohexane-isopropanol-butanone and three binary systems of ethanol-acetone,ethanol-n-hexaneacetone-n-hexane at the pressures from 101.3 to 911.O kPa.The variation of binary azeotropes with pressure were studied.The ternary azeotroplc data were predicted by Wilson equation on the basis of corresponding binary azeotropic data at the same pressures.The predicted values are in good agreement with the experimental data.
    BED EXPANSION IN THE DENSE REGION OF FCC TURBULENT FLUIDIZED BED
    Lu Chuuxi;Xu Yifang;Shi Mingxian;Shen Fu;Zhao Mimgang;Peng Jifeng(Petrnleum University,Beijing 102200)(Luoyang Petrochemical Engineeing Corporation,Luoyang 471003)
    1996, 47(1):  110-113. 
    Abstract ( 531 )   PDF (189KB) ( 205 )  
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    The bed expansion in the dense region of FCC turbulent fluidized bed has been studied in a cold fluidized bed made of plexiglass with 710×4000/870×ll000mm and a RFCC regenerator(800,000T/a).By using dimensional analysis,a calculation equation of dense phase density correlated by dimensionless groups is obtained.The equation may be use ful for process engineering design of commercial units.
    KINETICS OF COBALT EXTRACTION WITH MONO-(2-ETHYLHEXYL)2-ETHYLHEXYL PHOSPHONIC ACID FROM NITRATE SOLUTION
    Zheng Zuoxi;Gu Zhongmao;Wang Dexi(China Institute of Atomic Energy,Beijing 102413)
    1996, 47(1):  114-119. 
    Abstract ( 602 )   PDF (295KB) ( 127 )  
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    The kinetcs of extraction of cobalt with HEHEHP-kerosene solution from aqueous nitrate solution has been studied using the Lewis Cell.The effects of stirring rate and interfacial area were investigated.In the kinetic region,the influences of concentration of cobalt,hydrogen ion and HEHEHP were mainly studied.The effects of the sulphate,chloride,nitrate and acetate ions in aqueous phase on extraction rate were also discussed. The experimental results indicate that the extraction process may be governed by the mixed mechanism of diffusion and chemical reaction.In the kinetion,region,the extraction Process might be controlled by the following interfacial reactions The apparent rate constant was calculated to be about 3.63×10~(-13)mol·cm~(-2)·s~(-1).The sulphate,nitrate and chloride ions decrease the extraction rate in the order of SO_4~(2-)>NO~(-3)>CI~-.On the other hand,the acetate ion could greatly increase the extraction rate.The extraction rate with 0.025mol·L~(-1) acetate ion in aqueous phase is about four times of that without acetate ion.
    STUDY OF IGNITION TEMPERATURE IN FIXED-BED REACTOR
    Shao Mingwang(Department of Chemistry,Anhui Normal university,Wuhu 241000)
    1996, 47(1):  120-123. 
    Abstract ( 645 )   PDF (180KB) ( 115 )  
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    This paper discusses ignition temperature in a fixed-bed reactor by integral method.The results show that ignition will disappear as the diameter of reactor increases to some extent and the ignition temperature remains constant while the space time is unchanged though the length of reactor and reactant velocity are varied.
    EXPERIMENTAL STUDY ON STEAM FLOW CONDENSATION IN VERTICAL TUBE WITH A SPIRAL WIRE
    Wang Zhongzheng;Liu Kexin;Guo Xinchuan;Li Xiaopeng;Li Rujun(Thermal Energy Engineering Departmern,Tianjin University,Tianjin 300072)
    1996, 47(1):  124-128. 
    Abstract ( 715 )   PDF (252KB) ( 136 )  
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    An experimental study was made for steam condensation in a vertical tube with a spiral wire based on the turbulent-turbulen heat transfer model of steam-1iquid f1ow proposed by the authors,and data correlation was obtained.The distribution of steam content along flow length was calculated ad the influences of spiral wire,steam velocity,steam pressure and codensate film on condensation were analysed.The enhancement of condensation by the spiral wire was also demonstrated.