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Table of Content
25 June 1996, Volume 47 Issue 3
    化工学报
    EQUATION OF STATE FOR PREDICTING DENSITYS OF AQUEOUS ELECTROLYTES BY PERTURBATION THEORY
    Li Chunxi;Li Yigui;Lu Jiufang(Department of chemical Engineering,Tsingua University,Beijing 100084)
    1996, 47(3):  259-266. 
    Abstract ( 616 )   PDF (331KB) ( 330 )  
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    The equation of state for aqueous electrolytes based on perturbation theory is simplified.By using the water molecule parameters and ionic diameters,the densities of 12 single aqueous electrolyte systems including strong acids,9 binary and 1 quaternary aqueous electrolyte systems at different temperatures are calculated.The correlation accuracy of densities is about 1% for single electrolyte aqueous and 2% for the prediction of densities of mixed electrolyte aqueous systems.The prediction accuracy can be improved by using the fitted cation diameter from the relevant single electrolyte systems instead of Pauling diameters.
    OPTIMAL SENSOR LOCATION FOR STATE ESTIMATION OF NONLINEAR DISTRIBUTED PARAMETER SYSTEMS
    Liu Lianghong;Zhou Xinggui;Yuan Weikang(UNILAB Research Center of Chemical Reaction Engineering,East China University of Science and Technology,Shanghai 200237)
    1996, 47(3):  267-272. 
    Abstract ( 575 )   PDF (338KB) ( 230 )  
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    Optimal sensor location for the state estimation of distributed parameter systems is studied.First a nonlinear state estimator is developed based on late lumping.The partial differential equations for state estimation and the differential sensitivity matrix are then solved numerically.Optimal sensor locations are obtained by minimizing a integral function over a spacial domain using a nonlinear constraint optimization method. A wall-cooled fixed-bed reactor is used as a working system,and the effects of measurement noise,model parameter errors,and unmeasurable disturbance are studied.Results show that with one or two properly placed temperature sensors,excellent state estimation of the fixed-bed reactor can be achieved.
    MAIHEMATICAL MODEL OF THERMAL PROCESS IN COMPLEX STRUCTURE FURNACE WITH NONHOMOGENEOUS MEDIUM
    Li Benwen;Chen Haigeng;Ning Baolin;Tao Wenquan(School of Energy and Power Engineering,Xian Jiaotong University,Xian 710049)(Department of Thermal Engineering,Northeastern University,Shenyang 110006)(School of Energy and Engineering,Xian Jiaotong Univer
    1996, 47(3):  273-279. 
    Abstract ( 548 )   PDF (316KB) ( 123 )  
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    The uniform deterministic discrete method (UDDM) is used to compute the direct exchange areas of zonal analysis in a complex enclosure with participating medium.FOr solving energy matrix equations,the principal variable correction method is adopted,and its principle is described in this paper together with an explanation of its Physical basis.In order to combine the calculations of radiation and convection,a two-level grid is used.The results from this model have shown that a series of calculation methods on radiative heat-exchange in this paper can meet the case of engineering accuracy.
    GENETIC ALGORITHMS AND ARTIFICIAL NEURAL NETWORK(Ⅰ)──TRAINING ARTIFICIAL NEURAL NETWORK WITH EXTENDED GENETIC ALGORITHMS
    Chen Fangze;Chen Bingzhen;He Xiaorong(Department of Chemical Engineering,Tsinghua University,Beijing 100084)
    1996, 47(3):  280-286. 
    Abstract ( 525 )   PDF (323KB) ( 215 )  
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    In order to overcome a local optimal solution which often occurs in the training process of artificial neural networks,a new algorithm called EGA is proposed.An adaptive multipoint mutation operator,which can effectively extinguish the swing problem in convergent process,is proposed in this algorithm.So the speed of BP training is improved.A reasonable mutation factor range is found.As a result,the speed and accuracy of training artificial neural networks are much improved.
    OPTIMIZATION ANALYSIS OF LOW PRESSURE DEMETHANIZATION PROCESS
    Wang Hongshi;Zhou Pei;Song Weiduan(Department of chemical Engineering,East China Universiy of Science and Technology,Shanghai 200237)
    1996, 47(3):  287-292. 
    Abstract ( 603 )   PDF (293KB) ( 291 )  
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    In this paper based on simulating computation of low-pressure demethanization process in an ethylene Plant,an optimization mathematical model using the sum of ethylene loss and energy consumption Of the system as its objective function is established.The optimun operation conditions and key operation variables are given by the “black box” method combined with the generalized reduced gradient method,one of the most reliable tools for optimun design.A useful study is carried out on the selection of optimal key variables and the optimal strategy of medium-size flow-sheeting system.
    KINETICS EQUATION OF 4-HYDROXYBENZALDEHYDE BROMIZATION
    Yuan Jitang;Jiang Haoxi;Wang Lianshun;Yin Jinzhu;Wei Dongwei(Research and Development Center for Petrochemical Technology,Tianjin University,Tianjin 300072)
    1996, 47(3):  293-298. 
    Abstract ( 670 )   PDF (267KB) ( 278 )  
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    For the bromization reaction of 4-hydroxybenzaldehyde in chloroform solvent,which results in precipitation of 3-bromo-4-hydroxy benzaldehyde and 3,5-dibromo-4-hydroxybenzaldehyde,the paper presents a method to calculate the concentration of clear liquid with material balance and solubility equations.Based on the above calculation a kinetics equation of 4-hydvoxybenzaldehyde bromization reaction is established.The average relative error between the values of experimental measurement and calculation is 6.37%.
    INVESTIGATION ON KINETICS OF DYNAMIC QUENCHING OF LUMINESCENT COMPLEXES IN POLYMER MATRIX
    Ruan Fuchang;Li Xiangming;Mo Binglu;Gong Guoqing;Deng Songjiu(Chemical Engineering Research,South China University of Technology,Guangzhou 510641)
    1996, 47(3):  299-304. 
    Abstract ( 492 )   PDF (278KB) ( 226 )  
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    Optical sensors are manufactured based on dynamic quenching of luminescent complexes immobilized in polymer matrix by a gaseous/liquid quencher. Based on the kinetic model of optical chemical reactions,a kinetic equation is deduced for determining quantitatively the concentration of a gaseous or liquid quencher.This equation can fit the luminescent quenching data and explain the mechanism of luminescent quenching reactions in polymer matrix very well,which shows that it is a simple and practical kinetic equation.
    LIQUID CHANNELLING AND ITS EFFECT ON PLATE EFFICIENCY
    Huang Jie;Song Haihua;Liu Fushan;Wang Zhongcheng(Chemical Engineering Research Center,Tianjin Universiry,Tianjin 300072)
    1996, 47(3):  305-311. 
    Abstract ( 606 )   PDF (361KB) ( 173 )  
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    Liquid channelling,a special nonuniform flow phenomenon on distillation plate,is studied.The hot-film anemometer is used to measure the liquid channelling flow rate on a φ1200 hing-turndown-ratio valve plate for the first time.The Plate is divided into two rregions,the bubbling region with mass transfer and the channelling region,and the difference equations of material balance in each region are solved to give the relationships between liquid channelling and plate efficiency under various operating conditions.The results can be utilized to determine the liquid channelling effect on industrial distillation.
    SEPARATION OF PROPYLENE BY FACILITATED TRANSPORT MEMBRANES (I) TECHNOLOGICAL CONDITIONS
    Qiu Liqin;Ma Shaofeng;Chen Hongfang(Research and Development Center for Petrochemical Technology,Tianjin University,Tianjin 300072)
    1996, 47(3):  312-318. 
    Abstract ( 546 )   PDF (339KB) ( 154 )  
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    The facilitated transport of propylene through supported liquid membranes containing silver nitrate as a carrier was realized.The effects of different technological conditions and membrane material etc.on the purity of propylene,the Permeation rates,once through yield of propylene and the selectivity factor were studied.Under best conditions,the purity of propylene is up to 99.3%~99.7%, the selectivity factor more than 700,once through yield of propylene up to 5.6%.The ways of improving supported liquid membranes stability were given.The Process of facilitated transport through supported liquid membranes is proved by practice to be superior to the process of dissolution-diffusion.
    SEPARATION OF PROPYLENE BY FACILITATED TRANSPORT MEMBRANES(Ⅱ) MATHEMATICAL MODELING
    Qiu Liqin;Ma Shaofeng;Chen Hongfang(Research and Development Center for Petrochemical Technology,Tianjin University,Tianjin 300072)
    1996, 47(3):  319-323. 
    Abstract ( 510 )   PDF (226KB) ( 150 )  
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    Propylene reacts with carrier Ag~+ instantaneously.A model equation for facilitated transport flux of propylene through liquid membranes was developed based on transport theory.The model parameters of two kinds of supports were determined by method of experimental data regression.The result proves the model correct.
    TEMPERATURE EFFECT ON SOLID-SUPERCRITICAL FLUID PHASE EQUILIBRIUM AND ITS MOLECULAR BASIS
    Zhao Suoqi;Wang Renan;Yang Guanghua(National Heavy Oil Research Laboratory University of Petroleum,Beijing 102200)
    1996, 47(3):  324-331. 
    Abstract ( 569 )   PDF (347KB) ( 113 )  
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    Temperature effect on solid-supereritical phase equilibrium and its molecular basis is studied in this Paper,based on the experimental isobaric solubility data of naphthalene/CO2 binary system.The Gibbs-Konowalow rule as well as PR-EOS are used to calculate the primary factor-solute excess partial molar enthalpy along the isobars.It is found that solute excess Partial molar enthalpy diverge negatively in retrograde region of the system and the temperature effect is significant.The strong exothermicity is explained by using Kirkwood-Buff solution theory.Solute excess partial molar enthalpy is proved to be proportional to cluster size of solvent molecules around a solute molecule.Theory and calculating results show that for an attractive system the stronger negative divergence of solute excess partial molar enthalpy corresponds to the larger cluster size.
    PREDICTION MODEL AND MEASUREMENT OF SINGLE PHASE PRESSURE DROP ON SHELL-SIDE OF TEMA-F HEAT EXCHANGER
    Yang Xiaoqiong;Wang Qijie;Wang Song(Department of Power Machinery Engineering,Xian Jiaotong University,Xian 710049)
    1996, 47(3):  332-339. 
    Abstract ( 590 )   PDF (358KB) ( 96 )  
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    Based on an analysis with Divided-flow Method,this paper shows that stream resistance coefficients mainly depend on the cross-sectional area and mass flow rate of different flow paths when crossflow Reynolds number Re(Tc)is high enough.The effects of geometrical shape of cross-sectional area can be neglected.Therefore pressure drop on the shell-side of a TEMA-F heat exchanger can be Predicted by using Divided-Flow Method for TEME-E heat exchanger.Experimental study was carried out.The experimental values of pressure drop and predicted values appear to be in good agreement.
    PREPARATION OF SILICA SOLS BY ELECTRODIALYSIS
    Liu Hongmei;Yi Bao Lian(Dalian Institnte of Chemical Physics,Academia Sinica,Dalian 116012)
    1996, 47(3):  340-345. 
    Abstract ( 686 )   PDF (317KB) ( 144 )  
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    An electrodialytic cell system equipped with a steel cathode,a RuOx/Ti anode and a piece of Nafion 901 cation-exchange membrane was set up in the process of producing silica sols by eletrodialysis of sodium silicate.It was confirmed that the deposition of silica on anodes can be minimized by increasing current density and the velocity of anolyte.The yield of silica was above 97% in the case of i>50mA·cm~(-2), u>0.3lm·s~(-1).The current efficiency of membrane was more than 90% when temperature was higher than 20℃ and current density was greater than 30mA·cm~(-2).Concentrated silica sols can be produced by electrodialysis in the process of adding concentrated sodium silicate (Xsio2=30%) into anolyte.The Optimal initial anolyte composition and operating conditions were obtained.The deposition of silica on anodes during the process can be overcome mainly if initial anolyte was dilute aqueous silica sols with particle size less than 5nm.The highest cell voltage was less than 10V,the greatest current density was about 150mA·cm~(-2) and the mean efficiency of membrane was about 93%.
    MASS FLUX PROFILES AND FLOW REGIMES IN A HIGH DENSITY CIRCULATING FLUIDIZED BED
    Wei Fei;Lu Fangbin;Jin Yong;Yu Zhiqing(Department of Chemical Engineering,Tsinghua University,Beijing 100084)
    1996, 47(3):  346-351. 
    Abstract ( 726 )   PDF (326KB) ( 144 )  
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    Results of experimental measurement of solids mass flux profiles in a high density circulating fluidized bed riser over a wide operating condition are described.The existence of three solids flux radial profile regimes:core-annular,parabolic and U-shaped is found.A model for all the three regimes is proposed and correlations of model parameters are obtained.Comparison of predicted solids flux profiles with experimental data is very promising.The correlations for the boundaries of the three regimes and the radius of core for core-annular regime are obtained.
    PHENOMENOLOGICAL MODEL OF RHEOLOGICAL BEHAVIOR FOR SHEAR THINNING SUSPENSIONS
    Zhang Hui;Fang Tunan;Dai Gance(Department of Chemical Engineering,East China University of Scince and Technology,Shanghai 200237)
    1996, 47(3):  352-356. 
    Abstract ( 595 )   PDF (233KB) ( 192 )  
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    Based on Krieger-Dougherty equation,a phenomenological model is proposed to describe the structure parameter and maximum packing fraction changing with shear.After determining the model parameters from the experiment of yield strees measurement at various packing fractions,the suspension viscosity at different shear stress and packing fraction could be estimated.
    HYDRODYNAMIC BEHAVIORS OF GAS-SOLID-SOLID CIRCULATING FLUIDIZED REACTOR
    Huang Shuiyuan;Wang Zhanwen;Jin yong;Yu Zhiqing(Department of Chemical Engineering,Tsinghua University,Beijing 100084)
    1996, 47(3):  357-361. 
    Abstract ( 596 )   PDF (221KB) ( 143 )  
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    The modern developmentnts in research of gas-solid-solid reactors are briefly introduced,the operating characteristics of gas-solid-solid circulating fluidized reactor (GSSCFR) are also described.The hydrodynamic behaviors of GSSCFR,such as the pressure drop of gas-solid flowing through the Packed section,powders hold-up and solids flow rate,are studied.
    STATISTICAL THERMODYNAMIC MODEL FOR CALCULATION OF SURFACE TENSION OF PURE LIQUIDS
    Li Chunxi;Li Zhibao;Li Yigui;Lu Jiufang;Song Hongyan(Department of Chemical Engineering,Tsinghua University,Beijing 100084)(Department of Applied Chemistry,Shandong Institute of Building Materials,Jinan 250022)
    1996, 47(3):  362-366. 
    Abstract ( 608 )   PDF (263KB) ( 455 )  
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    two equations for the calculation of surface tension of pure liquids are derived based on statistical thermodyanics by expressing the intermolecular potential as lennard-Jones pair potential.This method is simple,accurate and easy to use.The calculation results for the 22 pure liquids show that these equations are superior to the empirical forula and other theoretical equations.The average relative deviations for these two equations are within 5% and 1.5% respectively.
    CALCULATION AND CORRELATION OF FLOW BOILING HEAT TRANSFER IN RECTANGULAR CHANNEL WITH 2mm GAP WIDTH
    Wu Yunying;Yang Wei;Gegen (Department of Chemical Engineering,Tianjin University,Tianjin 300072)
    1996, 47(3):  367-370. 
    Abstract ( 529 )   PDF (216KB) ( 212 )  
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    This research studied the flow boiling heat transfer characteristics in vertical rectangular channel with 2mm gap width under the thermosiphon circulation.It was found that convective evaporation heat transfer somehtimes was in a transitional flow state,the calculation method was not reported.An equation for convective evaporation was developed and was suitable for the calculations of laminar,transition and turbulent flow states.The absolute deviation of the calculated flow boiling heat transfer coefficient from the experimental data was 14.9% by this method.
    PREDICTIONS OF PROPERTIES OF TERNARY MIXTURE VIA ARTIFICIAL NEURAL NETWORK MODELS
    Cao Yilin;Lu Qingzhang;Yang Shuting(Department of Chemistry, Henan Normal University,Xinxiang 453002)
    1996, 47(3):  371-375. 
    Abstract ( 548 )   PDF (230KB) ( 119 )  
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    Artificial neural network models were used to investigate the density,viscosity and excess molar volume of a ternary mixture.The results were satisfactory when compared with the experimental values.This method was easy in operation and rapid in prediction comparing with the traditional thermodynamical methods based on empirical or semiempirical equations.It can be used as a unified method for the property prediction of multicomponent mixture.
    NEURAL NETWORK CONTROL FOR DISTILLATION TOWERS WITH MULTIPLE SIDE-STREAMS
    Chen Jie;Wang Shuqing;Wang Ning;Wang Jicheng(Institute of Industrial Process Control Technology,Zhejiang University,Hangzhou 310027)
    1996, 47(3):  376-380. 
    Abstract ( 604 )   PDF (241KB) ( 403 )  
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    With an example of a distillation tower,an important equipment in chemical industry,this paper gives an investigation into the multivariable intelligent controller using the neural network which includes the model of the Plant,the multivariable control systems,and the model-free intelligent control algorithm.The simulation results show that such a novel controller is effective to control the complex chemical prncesses.Having good performances,strong robustness to the changes of the process model and simple structure,it can be conveniently used in practical engineering.
    INVESTIGATION ON SUPERCRITICAL WATER OXIDATION OF HYDROQUINONE IN WASTE WATER
    Wang Tao;He Shengyue;Liu Chongyi;Shen Zhongyao(Department of Chemical Engineering,Tsinghua University,Beijing l00084)
    1996, 47(3):  381-384. 
    Abstract ( 550 )   PDF (201KB) ( 417 )  
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    Supercritical water oxidation of hydroquinone in waste water was investigated in a flow reactor at 390~540℃ and 25~35 MPa.Oxygen was used as the oxidant.The decrease efficiency of COD of the waste water could be more than 99%.The effects of temperature,pressure and residence time on the decrease efficency of COD of the waste water were studied.