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Table of Content
25 February 2000, Volume 51 Issue 1
    化工学报
    NOVEL TECHNOLOGY IN BIOSEPARATION PROCESS INTEGRATION OF AQUEOUS TWO-PHASE PARTITIONING WITH RELATED TECHNIQUES
    Lin Dongqiang,Zhu Ziqiang,Yao Shanjing and Mei Lehe (Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027)
    2000, 51(1):  1-6. 
    Abstract ( 787 )   PDF (828KB) ( 304 )  
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    The successful commercialization of biotechnology depends strongly on the development of separation processes. A novel technology to combine different separation operations into a single stage to give higher yield, greater selectivity and optimum scheme is described as the integration of bioseparation processes. Based on the integration of aqueous two phase partitioning with related techniques, the trends and advantages of integration in bioseparation processes are investigated. Some disadvantages in separation process are resolved after combining aqueous two phase partitioning with temperature induced phase separation,magnetic field,ultrasonic and colloidal gas aphron technology. Integration of aqueous two phase partitioning with affinity precipitation and chromatography increases significantly the efficiency of separation and simplifies the separation process. Furthermore,a new idea is developed to innovate bioseparation technology when aqueous two phase partitioning is integrated into bioconversation,chemical permeabilization or electrophoresis. In general, integration of bioseparation processes provides a good way of combining different techniques to improve and optimize the whole separation process.
    STABILITY ANALYSIS OF FILM DURING FLOW CONDENSATION IN VERTICAL SMALL DIAMETER TUBE
    Wang Buxuan ** and Du Xiaoze (Department of Thermal Engineering, Tsinghua University, Beijing 100084)
    2000, 51(1):  7-11. 
    Abstract ( 608 )   PDF (556KB) ( 234 )  
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    The Kelvin Helmholtz instability of phase change interface during filmwise flow condensation in a vertical small diameter tube is studied by means of energy consideration. Based on the rules that the interfacial waving comes from the balance of various forces doing work on the two phase flow system, the mechanism for the effect of the correlating factors on the stability of condensate film is to be explored in detail. The results indicate that, with decreasing tube diameter,gravity and vapor quality,Bernoulli effect and surface tension on vapor liquid interface may exert more obvious influence on condensate film waving,and hence,increase the instability of the film. Condensation and surface tension on the tube wall would stabilize the film,while the film becomes instable only in a certain range of disturbing wavelength. The results of this paper are helpful in understanding the film instability and the transition of flow pattern during flow condensation in a small diameter tube.
    INFLUENCE OF HEAT TRANSFER CONDITIONS ON PERFORMANCE OF OSCILLATORY TUBE
    Li Xuelai and Guo Rongwei (Department of Power Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016) [BHDWG6,WK26。2W]Fang Yaoqi (School of Chemical Engineering, Dalian University of Technology,Dalian 116012)Yu Hongru (Ins
    2000, 51(1):  12-16. 
    Abstract ( 593 )   PDF (590KB) ( 148 )  
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    The oscillatory tube respresents a simple arrangement for gas cooling by its decompression,and has many applications in chemical processes and energy transformation. The mechanism of the cooling effect of oscillatory tube is the conversion of the pressure energy of gas to heat through the movement of pressure waves,which are moving shock wave and unsteady expansion wave. The radial heat transfer through the tube wall will influence the performance of the oscillatory tube significantly. In the present paper, the effects of heat transfer conditions outside of an oscillatory tube on the performance of the tube are investigated experimentally. In the experiments,two kinds of typical heat transfer conditions,natural convection and forced convection(axially water cooled),are studied. The oscillatory tube is a red copper tube,14 mm in diameter and 4 2 m in length. The pressure ratio is in the range of 2 0—6 0. The ambient temperature is 15 ℃. The inlet temperature of the cooling water is 17 7 ℃ at a flow rate of 0 81 kg·s -1 . The experimental results show that the refrigerating efficiency of the tube is increased by 4 6%—5 4% when the heat transfer condition outside the tube wall is improved by axial water cooling. Also,the optimum pulsing frequency ( f opt ) of the driving jet flow is reduced significantly and the value of f opt is no longer affected greatly by the pressure ratio when the heat transfer outside of the tube is intensified. The theoretical analyses of the experimental results are also presented.
    APPROACH TO GROSS ERROR IDENTIFICATION OF INSTRUMENTS BASED ON RESIDUAL OF SINGLE NODE
    Wang Xiruo and Rong Gang (National Laboratory of Industrial Control Technology, Zhejiang University, Hangzhou 310027)
    2000, 51(1):  17-22. 
    Abstract ( 790 )   PDF (654KB) ( 287 )  
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    The problem of gross error detection and identification becomes the bottleneck of data reconciliation A new approach to gross error identification based on the reliability, precision ranking of the flowmeters as well as the residual of single node is presented It is assumed that the measurement error independently tends toward normal distribution and the reliability of every flowmeter is no lower than its lower limit The distribution of probability density for different situations of gross error at a single node is edfined The computation procedure for the different probabilities is given by using reliability and precision information of the instrument in/out a node and the residual of the node. Then the magnitude of different probabilities can be used as the criteria for gross error identification Two simulations are given and a comparison is made between the new approach and previous researches It is shown that the proposed method is quite effective in gross error identification especially when the system comprises of a relatively large number of flows
    GRAND CANONICAL ENSEMBLE MONTE CARLO SIMULATION OF ADSORPTION STORAGE OF METHANE IN SLIT MICROPORES
    Cao Dapeng,Gao Guangtu and Wang Wenchuan (College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029)
    2000, 51(1):  23-30. 
    Abstract ( 895 )   PDF (908KB) ( 363 )  
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    Adsorption behavior of methane has been simulated by using the grand canonical ensemble Monte Carlo (GCEMC) method Methane is modeled as a spherical LJ molecule, and the 10 4 3 potential is used for the description of the interaction between methane and a slit pore in the GCEMC simulation To test our program,adsorption,desorption and capillary condensation are simulated at T =74 05 K The adsorption isotherm and local density profiles obtained are in good agreement with data from Jiang et al Then,the adsorption storage behavior of methane in various slit pores at T =300 K is simulated The adsorption isotherms and effective storage values changing with pressures and slit pore widths are presented The best slit width and reasonable adsorption pressures for the adsorption of methane at T =300 K are recommend
    COMPUTATIONAL MODELING OF DENSE GAS-PARTICLE FLOW IN A PIPE:KINETIC THEORY APPROACH OF GRANULAR FLOW
    Lu Huilin,Liu Wentie and Zhao Guangbo (Department of Power Engineering, Haerbin University of Technology, Haerbin 150001)Dimitri Gidaspow (Department of Chemical and Environmental Engineering, Illinois Institute of Technology,Chicago 60616)
    2000, 51(1):  31-38. 
    Abstract ( 768 )   PDF (841KB) ( 161 )  
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    Conservation of mass,momentum and fluctuation energy equations for solid and gas phases are used to compute the hydrodynamics of flow in a vertical riser. The present two phase flow model is derived starting from the Boltzman equation for velocity distribution of particles. The model is generated from the Navier Stokes equation,except that the solids viscosity and stresses are computed by simultaneously solving a fluctuating energy equation for the particulate phase. The turbulence of the gas phase is treated using a SGS turbulence closure model. A no slip boundary condition for the gas phase and slip boundary condition for the particulate phase are used. The model predicted the core annular flow structure in a riser,similar to that found experimentally in a dense gas solid flow. The predicted time averaged particle concentration,velocity and viscosity of particles are compared with the experimental data of Miller and Gidaspow and reasonable agreement is observed in a circulating fluidized bed. It is shown that the flow behavior is strongly affected by the plastic fluctuation energy,and the momentum and energy transfer between the particulate and the fluid constituents.
    EXPERIMENT ON STRONGLY SWIRLING TURBULENT GAS-PARTICLE FLOWS WITH SWIRL NUMBER OF 1.0
    Xu Yi,Zhou Lixing and Cao Dong (Department of Engineering Mechanics,Tsinghua University,Beijing 100084)
    2000, 51(1):  39-44. 
    Abstract ( 613 )   PDF (672KB) ( 128 )  
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    Strongly swirling flows are frequently encountered in cyclone separators,cyclone combustors and hydrocyclones .Their flow behavior significantly affects the pressure drop,collection efficiency,flame stabilization,combustion efficiency and pollutant formation.Previously this kind of flow with swirl numbers of 0 47,1 5 and 2 08 was studied. To further clarify the effect of swirl number,strongly swirling turbulent gas particle flows in a cylindrical chamber with axial and tangential inlets and a swirl number of 1 0 were studied using a phase Doppler particle anemometer.The measurements give the gas phase and particle phase axial,tangential and radial mean velocities,turbulent fluctuation velocities and particle concentration.The results show the change of flow behavior with the increase of swirl number.As the swirl number increases,the reverse flow region in axial velocity profiles gradually dissappears and the particle axial velocity changes from exceeding the gas velocity in some regions to lagging behind the gas velocity everywhere.For all swirl numbers the tangential velocity profiles of two phases have Rankine vortex structure and the particle tangential velocity always lags behind the gas one.With the increase of swirl number,the relative size of the soild body rotation zone in tangential velocity profiles increases.The two phase turbulent fluctuation is anisotropic for all swirl numbers.With the increase of swirl number the axial fluctuation changes from exceeding the tangential one to lagging behind the tangential one.ne.Withthe
    SIMULATION OF HYDROLYTIC POLYMERIZATION OF CAPROLACTAM——EFFECT OF BIFUNCTIONAL REGULATOR ON DISTRIBUTION OF POLYMER COMPOSITIONS
    Xie Jianjun (Institute of Polymer Science and Engineering, Xiangtan University,Xiangtan 411105)Tang Zhilian and Huang Nanxun (Department of Environment Science and Engineering, China Textile University,Shanghai 200051)
    2000, 51(1):  45-51. 
    Abstract ( 787 )   PDF (652KB) ( 138 )  
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    A simulation model dealing with the kinetic behavior of the hydrolytic polymerization of caprolactam with bifunctional regulator is proposed to analyze such characteristic data of the polymerization as the concentrations of caprolactam,cyclic dimer,as well as conversion, number average and weight average polymerization degrees ,and polydispersity indexs The calculated values based on the model agree well with the experimental data The results show that the number average polymerization degree (NAPD) decreases with increasing concentrations of water,aminocaproic acid and relative molecular mass regulator(RMMR) and that the effect of the concentration of water is more obvious, while NAPD does not basically change when the concentration of RMMR is smaller than 0 0068 mol·kg -1 and NAPD decreases when it is greater than 0 068 mol·kg -1 . NAPD also decreases with the increase of concentration of water when the concentrations of aminocaproic acid and RMMR are equal to zero
    CHARACTERISTICS OF ENHANCEMENT OF FLOW BOILING HEAT TRANSFER WITH KEROSENE INSIDE INTERNALLY RIBBED TUBE
    Cheng Lixin (Department of Industrial Equipment and Control Engineering, South China University of Technology, Guangzhou 510641)Chen Tingkuan (National Laboratory of Multiphase Flow in Power Engineering,Xi ’an Jiaotong University, Xi ’an 710049)
    2000, 51(1):  52-56. 
    Abstract ( 620 )   PDF (594KB) ( 140 )  
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    To meet the need of modifying the boiling equipment used in petrol chemical industry, flow boiling heat transfer experiments with kerosene in smooth tube and internally ribbed tube are conducted respectively under the condition of 3×10 5 Pa(absolute atmosphere pressure). The experimental results are compared with each other. It shows that the flow boiling heat transfer coefficients in the internally ribbed tube are 1 6—2 times that in the smooth tube and flow boiling heat transfer under the condition of smaller temperature difference can be achieved in the internally ribbed tube. On the basis of the experimental results, a correlation of flow boiling heat transfer coefficient of kerosene in the internally ribbed tube is proposed. Finally the characteristics of flow boiling heat transfer with kerosene and mechanism of enhanced heat transfer in internally ribbed tube are analyzed.
    KINETICS OF ENZYMOLYSISES FOR PRODUCTION OF D-p-HYDROXYPHENYLGLYCINE BY sp.2262 CELL
    Zhang Yankun, Zhang Mingjun *, Li Jinghua, Li Shuguang and Yu Xingju (Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116012)
    2000, 51(1):  57-62. 
    Abstract ( 583 )   PDF (648KB) ( 147 )  
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    Kinetics of enzymolysises for the production of D p hydro xyphenylglycine from DL p hydro xyphenylhydantion by Pseudomonas Putida cells containing both hydroxypyrimidinehydrase and N carbamoyl D aminoacid amidohydrolase were studied. Dissolution process of DL p hydroxyphenylhydantoin and characteristics of both enzymes were investigated. The results showed that enzymolysis catalyzed by hydro xypyrimidinehydrase accorded approximately with first order kinetics, while that catalyzed by N carbamoyl D aminoacid amidohydrolase could be described by modified Michaelis Menton equation. It was found that enzymolysis catalyzed by N carbamoyl D aminoacid amidohydrolase was inhibited by the high concentration substrate and the byproduct NH 3. The kinetic model of whole process was developed. The values of model parameters were given. The influence of pH on model parameters was discussed and optimum operation conditions were established .
    DISTRIBUTION OF MOISTURE CONTENT FOR COMPOUND DRYERS OF FLASH AND FLUIDIZATION WITH CIRCULATING SYSTEM OF SOLIDS
    Ye Shichao (Department of Chemical Engineering,Sichuan University, Chengdu 610065)
    2000, 51(1):  63-69. 
    Abstract ( 542 )   PDF (829KB) ( 143 )  
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    The density function was developed for predicting the distribution of moisture content of compound dryers of flash and fluidization with a circulating system of solids The moisture content distribution of drying FeSO 4·7H 2O was calculated. The results show that there are three necessary conditions for the optimum design of fluidized dryers. The first is the heat supply for drying process. The bottom area of fluidized beds is deter mined in terms of the required heat supply. The second is the average residence time of particulate material in fluidized beds. The volume of fluidized dryers is calculated from the mean residence time. And the last is the uniformity of product moisture content. The number of rooms of fluidized beds is predicted in order to satisfy the required uniformity.msofthereq
    NUMERICAL SIMULATION OF TURBULENT FLOW IN STIRRED TANK AGITATED BY AXIAL IMPELLER
    Hou Shuandi, Zhang Zheng,Wang Yingchen and Shi Litian (Department of Chemical Engineering,Beijing University of Chemical Technology,Beijing 100029)
    2000, 51(1):  70-76. 
    Abstract ( 604 )   PDF (684KB) ( 155 )  
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    In this paper a standard k-ε model is used to predict the turbulent flow generated by an axial impeller in a cylindrical baffled vessel. The model predictions successfully reproduce the three dimensional characteristics of flow, and are in good agreement with those obtained by PDA measurement.The simulation results show that the ratio of impeller diameter to tank diameter ( D/T )has a great effect on the flow pattern in a stirred tank.For the small diameter impeller,such as D =0 35 T ,the primary circulation loop is smaller than the whole vessel size,a weak secondary circulation loop is formed in the upper region of the tank.With increasing impeller diameter,axial flow is enforced and the primary circulation loop is extended to the tank top and the secondary circulation in the upper region of tank disappears.The simulation results also demonstrate that the flow in front of baffles is different from the flow behind baffles for the impeller D/T =0 55.In front of baffles, axial flow dominates and only one circulation loop is formed.The flow pattern is approximately the same.Behind baffles,axial flow becomes weaker,and the fluid turns inward just above the impeller level.A small second recirculation loop is formed in the upper part of the vessel,and is directed downwards rather than upwards.
    MATHEMATICAL MODEL AND SCALE-UP OF EXTERNAL-LOOP AMMONIATION REACTOR
    Liu Qichong,Xia Daikuan,Duan Tianping,Zhang Yunxiang and Wang Jianhua (Department of Chemical Engineering,Sichuan University, Chengdu 610065)
    2000, 51(1):  77-84. 
    Abstract ( 586 )   PDF (973KB) ( 128 )  
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    Flow and mass transfer model as well as scale up of an external loop ammoniation reactor are studied under commercial condition in this paper. The results show that the flow model in reactor approches perfect mixed flow, when the recycle ratio β is 22 1 and the model parameter m is near 1. The model is fitted with the actual operation condition and can be used to scale up for commercial reactor. The previous research, in which macro kinetics of ammoniation of phosphoric acid was measured in a double magnetic stirring reactor,found that the reaction between wet phosphoric acid and gaseous ammonia was a rapid reaction controlled by the gas film mass transfer. Hence a new mass transfer model based on this mechanism is obtained by using a laboratory reactor. The model is studied on a pilot scale reactor with a capactiy of 10 kt MAP·a -1 , and then verified by using an commercial reactor with a capacity of 60 kt MAP·a -1 . The final mass transfer model of reactor is as follows:k G a=0 61W 0 3 a q 1 2 a The model is used for reactor scale up to a large commercial scale of 120 kt MAP·a -1 . It is found that the key factor of scale up should be q a= W a S t/ S r, i,e the ammonia loaded kg per unit time, per unit cross section area of reaction tube.
    EXTRACTION OF p-AMINOBENZENE SULFONIC ACID WITH TRIALKYLAMINE(7301) BASED ON CHEMICAL COMPLEXATION
    Li Zhenyu,Yang Yiyan and Dai Youyuan ** (Department of Chemical Engineering,Tsinghua University,Beijing 100084)
    2000, 51(1):  85-89. 
    Abstract ( 585 )   PDF (636KB) ( 137 )  
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    Based on systematic investigation and analysis of literature, p aminobenzene sulfonic acid is selected as a typical solute to be separated from dilute solution.An aliphatic,straight chain tertiary amine,7301,is used as complexing agent.Since the pH of aqueous solution is an important factor in chemical complexation extraction of p aminobenzene sulfonic acid,its effect on extraction equilibium is especially studied in the experiments.The effects of concentration of complexing agent and type of diluents on distribution ratio D are also investigated.Meanwhile,the proton transfer equilibrium is discussed.By using Mass Action Law,an expression of equilibrium distribution ratio for 7301 system is proposed.The results show satisfying precision of the model.
    CRITICAL PROPERTIES OF POLYDISPERSED FLUID MIXTURES
    Cai Jun,Ying Xugen,Liu Honglai ** and Hu Ying (Department of Chemistry,East China University of Science and Technology,Shanghai 200237)
    2000, 51(1):  90-95. 
    Abstract ( 637 )   PDF (645KB) ( 127 )  
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    Based on the stability theory of a multicomponent system, the criteria of spinodal and critical point for the mixture consisting of one discrete component and one polydispersed component described in the equation of state are derived If the continuous components are regarded as an intuitive single component, the criteria can be divided into two parts: the first part is the same as the criteria of a binary system, the second one is related to the distribution of polydispersed component The van der Waals equation of state is used to calculate the critical loci of an intuitive system The influence of average molecular weight and its dispersity on the critical phase behavior is examined
    OPTIMAL DESIGN OF HEAT EXCHANGER NETWORKS SYNTHESIS BASED ON EXERGY-ECONOMIC OBJECT AND STRATEGY OF DECOMPOSITION AND COORDINATION
    Li Zhihong and Hua Ben (Institute of Chemical Engineering,South China University of Technology, Guangzhou 510641)
    2000, 51(1):  96-101. 
    Abstract ( 737 )   PDF (835KB) ( 127 )  
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    This paper analyses the function of heat exchanger networks(HEN) is a process system, and states the essence of energy evolvement and diversification in the process system The paper indicates that the optimal objective function of all of the previous methods expressed by the sum of cold utility and hot utility for the energy cost is not rational Actually, from the exergy analysis point, it is the exergy dissipation that drives the process of heat transfer The energy cost and its objective function should be expressed based on exergy analysis and exergy economics So,this paper presents the exergy economic objective function of HEN synthesis from exergy analysis and exergy economics,which contains the flow exergy dissipation of HEN Moreover,this paper proposes the optimal mathematical model and the procedure of HEN optimal synthesis, shows that the exergy economic objective function of HEN can be decomposed into the sum of overall cost of each match unit . The strategy of decomposition and coordination is proposed based on the resolvability of HENs exergy economic objective function, which is between optimization of network and optimization of match units The cost of flow exergy dissipation of HEN is considered simultaneously for HEN synthesis The method proposed in this paper can obtain not only the optimal structure of HEN but also the optimal operation parameters of each match unit Finally, a case study demonstrates the potential application of this method
    ADSORPTION CHARACTERISTICS OF LARGE BIOMOLECULES
    Jin Hao and Jiang Tiqian (College of Chemical Engineering, East China University of Science and Technology, Shanghai 200237)
    2000, 51(1):  102-107. 
    Abstract ( 678 )   PDF (775KB) ( 150 )  
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    An adsorption dynamics model for large biomolecules is devloped by using RSA LRS theory The calculated values are obtained by orthogonal collocation method(OCM) The special features as large molecules and biological activity are considered during set up of mathematical model The predicted results are in good agreement with experimental data It is indicated that the mathematical model is suitable for the mass tranfer of LDL and VLDL The simulation computation can be used for designing,operation and optimizing the adsoption system in clinical treatment
    MASS TRANSFER CHARACTERISTICS OF INTERFACIAL LAYER MECHANICALLY ACTIVATED IN LIQUID-LIQUID SYSTEM
    Zhang Dongxiang,Xue Rongshu and Tan Shiyu (Department of Chemical Engineering, Chongqing University, Chongqing 400044)Tarasov V V (D.Mendeleyev University of Chemical Technology of Russia,Moscow 125190)
    2000, 51(1):  108-114. 
    Abstract ( 673 )   PDF (1037KB) ( 196 )  
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    The response of differential coefficient of mass transfer and differential rate of mass transfer in dynamic interface layers to the controlled mechanical interface activation has been investigated for inorganic acid (salt) liquid liquid extracting (reverse extracting) systems in the modified Lewis cell It can be seen from the results that periodic mechanical activation in interface layers not only affects the diffused penetrability in phase interfaces, enhances the process of mass transfer between phases, and improve the conditions of mass transfer in phases of liquid liquid systems, but also reduces the error of experiments The formation and development of differential polyphase layers determine the momentum and mass transfer characteristics in phases The result that the activation in phase interfaces is helpful for the formation of Marangoni spontaneous surface convection and other experimental phenomena in literatures are interpreted by using the idea of differential polyphase layers
    SYNTHESIS OF CUMENE BY SUSPENSION CATALYTIC DISTILLATION PROCESS
    Wen Langyou,Min Enze,Pang Guici and Yu Wenyou (Research Institute of Petrochemical Processing,Beijing 100083)
    2000, 51(1):  115-119. 
    Abstract ( 817 )   PDF (707KB) ( 283 )  
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    A novel catalytic distillation process using a catalyst suspension is studied with the alkylation of benzene with propylene as a model reaction This new process is designated as “suspension catalytic distillation” (SCD) Exploratory experiments indicate that SCD can be operated steadily as long as a suitable catalyst is used For the synthesis of cumene in the SCD process, 100% conversion of propylene with more than 90% selectivity to cumene can be obtained under very mild conditions: atmospheic pressure, low temperature (80—100 ℃), low benzene/olefin mole ratio (1 75—3) The cumene product has extremely high purity with both n propylbenzene and C 8 aromatic less than 100ppm Compared with conventional Catalytic Distillation,SCD has many advantages,such as:① No need to manufacture catalytic packing;② No need to shut down the unit to replace the spent catalyst;③ Mass and heat transfer are better with fine catalyst particle than catalytic packings The SCD process is an advanced new catalytic distillation technology and is prospective and obviously worthwhile for further R & D efforts.
    VELOCITY OF DROPLET WITH SORPTION-CONTROLLED SURFACTANT IN ELECTROLYTE SOLUTION
    Chen Jinnan and Peng Jiong (School of Chemical Engineering and Materials Science,Beijing Institute of Technology,Beijing 100081)
    2000, 51(1):  120-125. 
    Abstract ( 599 )   PDF (456KB) ( 138 )  
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    In this paper,monolayer saturation and nonideal surfactant interactions are captured with a nonlinear adsorption framework.The migration of a droplet in surfactant solution with electrolyte is discussed.Most prior research studied the migration of a bubble or a droplet in surfactant solution without electrolyte.When the surfactants in solution with electrolyte are adsorbed at the surface of a bubble or a droplet,an electrical double layer will form near the surface of the bubble or the droplet,which will affect the subsequent adsorption of the surfactants.A group of dimensionless parameters(the interaction coefficient of the adsorbed surfactants K ∞ ,the Marangoni number Ma ,the Biot number Bi and the viscosity ratio k )are discussed in detail.The surface concentration of the adsorbed surfactants,the surface velocity and the migration velocity of the droplet are obtained by a boundary collocation technique.The terminal velocity U 0 of the droplet increases as K ∞ increases.
    DIFFUSION OF AROMATIC HYDROCARBON IN ZSM-5 CALCULATED BY IMPROVED DATA TREATMENT OF ZERO LENGTH COLUMN METHOD
    Han Minghan,Yin Xiuyan and Jin Yong (Department of Chemical Engineering,Tsinghua University, Beijing 100084)Chen Shu and Zhang Jirui (Center for Chemical Engineering, Beijing Institute of Clothing Technology,Beijing 100029)
    2000, 51(1):  126-129. 
    Abstract ( 656 )   PDF (381KB) ( 155 )  
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    Intracrystalline diffusivities for aromatic carbon in ZSM 5 were measured by ZLC method. Experiments were analyzed by two traditional methods (LT method and ST method) and a new full range method. The traditional mathematical description of the ZLC technique by LT method or ST method will cause deviation unavoidably. The new full range method avoids the problems caused by the traditional methods, so it is more suitable to analying ZLC experiments. Diffusion coefficients calculated by FR method are greater than those by LT method, but smaller than by ST method.
    MEASUREMENT OF EFFECTIVE DIFFUSION COEFFICIENT OF MACROMOLECULES IN POLYMER GELS
    He Mingxia ,Xu Jiankuan and He Zhimin (Chemical Engineering Research Center, Tianjin University,Tianjin 300072)Zuo Ju (Department of Chemistry,Nankai University, Tianjin 300071)
    2000, 51(1):  130-132. 
    Abstract ( 764 )   PDF (297KB) ( 194 )  
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    A new data analysis method of dynamic light scattering of gels with macromolecules was proposed,in which the inhomogeneity of polymer gels was taken into account.The reliability of the method was verified by measuring the effective diffusion coefficient of Lysozyme in polyacrylamide gels.The dependence of the effective diffusion coefficient of macromolecules on monomer concentration was also observed.
    KINETICS OF THERMAL DECOMPOSITION OF HYDROXYLAMINE PERCHLORATE
    Mi Zhentao,Chang Zhihua, Zhang Xiangwen, Qiu Liqin and Wang Yaquan (School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072)
    2000, 51(1):  133-136. 
    Abstract ( 665 )   PDF (446KB) ( 216 )  
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    Hydroxylamine perchlorate (HAP) is a new energetic oxidizer. The thermal decomposition of pure HAP and the effects of additives on thermal decomposition of HAP were studied by using TG and DTA in nitrogen atmosphere. The additives are 4 0% NH 4ClO 4, 3 0% HClO 4, and 0 29% FeCl 3 respectively. The TG curves of the above four systems were determined. The experimental results indcate that FeCl 3 has a promoting effect on the decomposition of HAP,but NH 4ClO 4 and HClO 4 have no such effect on the decomposition of HAP. NH 4ClO 4 acts as an inert substance, and HClO 4 has a weak retarding effect on the decomposition of HAP. By using non isothermal TG DTG,the thermal decomposition kinetic equations of the four systems were obtained. Through comparing the kinetic parameters of the four systems,the order of decomposition activation energy ( E ) and reaction order ( n ) were found: HAP+0 29% FeCl 3
    FLOW FIELD AND MIXING RESULT IN MIXER BY FLOW VISUALIZATION TECHNIQUE
    Ruan Xiaodong and Fan Yurun (State Key Laboratory of Fluid Power Transmission and Control,Zhejiang University, Hangzhou 310027)Song Xiangqun and Yamamoto Fujio (Department of Mechanical Engineering, Fukui University, Fukui 910 8517)
    2000, 51(1):  137-140. 
    Abstract ( 754 )   PDF (450KB) ( 163 )  
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    In this paper the flow field in a static mixer is measured by Particle Image Velocimetry (PIV), which belongs to the technique of flow visualization. The vorticity field is obtained from the velocity field. The sequences of particle images are analyzed statistically and the mixing homogeneity degrees are also determined by calculating probability densities. The relation between the mixing result is also related to the state of flow. The experiment show that the mixing is mainly affected by the motion of vortices, not turbulence diffusion.