Please wait a minute...
Table of Content
25 June 1994, Volume 45 Issue 3
    化工学报
    SMELTING REDUCTION OF PHOSPHORUS ORE (Ⅰ) LABORATORY INVESTIGATION ON PHOSPHATE REDUCTION
    Guo Zhancheng,Wang Daguang and Xu Zhihong(Institute of Chemical Metallurgy, Academia Sinica,Beijing 100080)
    1994, 45(3):  257-264. 
    Abstract ( 633 )   PDF (411KB) ( 260 )  
    Related Articles | Metrics
    In order to develop the process of smelting reduction of phosphorus ore,the reduction of phosphate in molten slag was investigated in laboratory. The experiment results showed that there existed three reactions of phosphate reduction,i, e. , solid carbon,carbon in liquid iron saturated with carbon and phosphorus, and CO gas could reduce phosphate in the slag under the conditions of smelting reduction. The basic data were obtained for the research on kinetics of phosphate reduction.
    SMELTING REDUCTION OF PHOSPHORUS ORE (Ⅱ) KINETICS OF PHOSPHATE REDUCTION
    Guo Zhancheng, Wang Daguang and Xu Zhihong(Institute of Chemical Metallurgy, Academia Sinica, Beijing 100080)
    1994, 45(3):  265-271. 
    Abstract ( 629 )   PDF (348KB) ( 179 )  
    Related Articles | Metrics
    The kinetics of the reduction of phosphate in molten slag by solid carbon,carbon in liquid iron saturated with carbon and phosphorus and CO gas was studied. Under the conditions of slag basicity CaO/SiO2 = l. 1,and A12O3 around 8. 3% ,the reaction rate constant of reduction of phosphate in molten slag by solid carbon was expressed byThe rate constant increased with the slag basicity. The rate constant of phosphate reduction by carbon in liquid iron saturated with carbon and phosphorus was about ten times larger than that by solid carbon under the same conditions. The reduction rate by CO gas only depended on the flow rate of CO gas. Its reduction reaction was close to thermodynamic equilibrium.
    FRACTAL CHARACTERISTIC OF GAS DIFFUSION IN POROUS MEDIA
    Zhang Baoquan,Li Shaofen and Liao Hui(Department of Chemical Engineering, Tianjin University, Tianjin 300072)
    1994, 45(3):  272-278. 
    Abstract ( 525 )   PDF (296KB) ( 132 )  
    Related Articles | Metrics
    The pore inside porous media is abstracted into a fractal curve after analysis in this paper. The fractality of the fractal curve is defined as a spectral or fracton dimension d , the value of which is in the range 1≤ d< 2 . According to a scaling relation that relates the real length of a fractal curve to its shadow and yardstick size, an equation of diffusion flux for two - component gas mixtures in porous media is deducedwhich can also be used to measure d in terms of experimental data of diffusion.After presenting a practical equation calculating the yardstick size in this case, the method to determine d is subsequently offered. The above procedure is applied to Ni /γ-Al2O3 catalyst . The result of calculation shows that the internal pores of catalyst Ni /γ-Al2O3 can be featured as a fractal with respect to gaseous diffusion processes with its spectral or fracton dimension d = 1. 10.
    HYDRODYNAMICS OF THREE-PHASE FLUIDIZED BED IN RISER
    Ren Zhengwei ,Yan Yongjie, Xue Weilan and Li Jianjun(Department of Chemical Engineering of Energy Resources , East China University of Science and Technology, Shanghai 200237)
    1994, 45(3):  279-287. 
    Abstract ( 535 )   PDF (434KB) ( 285 )  
    Related Articles | Metrics
    The hydrodynamics of Newtonian and Non- Newtonian fluids in gas- liquid- solid fluidized bed in riser were studied. The circulation conditions for light and heavy particles were compared. The effects of gas and liquid flow rates,liquid viscocity,solid holdup and particle characteristics on gas holdup and liquid circulation rate were investigated. The difference between gas holdup in riser and that in the annular region and the influence of this difference on liquid circulation rate were studied. By introducing the generalized Reynolds number, the correlations for calculating riser and annular gas holdup for both Newtonian and non-Newtonian fluids were obtained.
    MEASUREMENT AND THEORETICAL APPROACH OF THE THIRD METASTABLE ZONE OF CRYSTALLIZATION
    Liu Junji,Shi Yuwen and Song Shimo(Chemistry Department of Tianjin University,Tianjin 300072)
    1994, 45(3):  288-292. 
    Abstract ( 564 )   PDF (227KB) ( 237 )  
    Related Articles | Metrics
    The concept of "the third metastable zone" of crystallizaton from aqueous solution is proposed in this paper. The width of the metastable zone is found much wider than the first one and the second one by measuring a few kinds of aqueous solution of salts. In addition, the solid -liquid interfacial tension σ, the radius of critical nucleus r* and the number of molecules in a critical nucleus i* are obtained by processing the experiment data with classical homogeneous nucleation theory.
    ELECTROLYTIC ACTIVITY COEFFICIENT AND SOLVATED NUMBER
    Zhang Suojiang and Han Shijun(Chemistry Department of Zhejiang University, Hangzhou 310027)
    1994, 45(3):  293-297. 
    Abstract ( 501 )   PDF (232KB) ( 187 )  
    Related Articles | Metrics
    In this paper the extended Debye-Huckel formula is used to represent the activity coefficient of solvated ions, and osmotic coefficient ? in the formula is cancelled by mathematical treatment. So a new formula for electrolytic activity coefficient, which contains only a single parameter h, is established. In order to test the reliability and practicability of the new formula, the activity coefficients of 48 electolyte- containing systems reported in literature are calculated. The results show good accuracy. Generally, the mean relative deviation of every processed system is less than 0. 8%.
    TEST OF ACTIVITY COEFFICIENT MODELS BY MOLECULAR SIMULATION
    Jia Chunshan,Wang Wenchuan and Lu Huanzhang(Department of Chemical Engineering, Beijing Institute of Chemical Technology, Beijing 100029)
    1994, 45(3):  298-305. 
    Abstract ( 552 )   PDF (402KB) ( 121 )  
    Related Articles | Metrics
    The Wilson, NRTL, UNIQUAC, and Wang - Chao activity coefficient models have been investigated in terms of the GE data from the Monte Carlo simulation carried out by the authors. In this investigation, several expressions for different local composition and coordination number definitions have been tested. Molecular parameters for the Lennard -Jones fluids have been introduced to each model to clarify the influences of the variables, including molecule size, interaction energy, composition, temperature, and pressure. As a result, analysis on the molecular assumptions and inherent shortcomings for these activity coefficient models provides a guidance for their improvement.
    EFFECT OF MAL - DISTRIBUTED WEEPING ON DISTILLATION TRAY EFFICIENCY
    Huang Jie ,Zeng Aiwu and Yu Guocong (K. T. Yu)(Chemical Engineering Research Center, Tianjin University,Tianjin 300072)
    1994, 45(3):  306-312. 
    Abstract ( 615 )   PDF (336KB) ( 209 )  
    Related Articles | Metrics
    A mathmatical model for predicting Murphree tray efficiency was proposed with consideration of the mal- distributed weeping, non- uniform liquid flow , unequal directional eddy diffusivity and variation of Murphree point efficiency across the tray. Two typical cases of mal- distributed weeping in industrial columns were used to illustrate how the Murphree tray efficiency could be further decreased in comparison with uniform weeping.The calculated results showed that the extent of Murphree tray efficiency drop depended on the degree of mal-distribution of weeping ,especially when weeping was intensified near the inlet weir as often appeared on large trays due to higher hydrostatic liquid head . The unfavorable effect of mal- distributed weeping should not be ignored in setting up the lowest limit of vapor velocity.
    EFFECTS OF FLUID PROPERTIES ON SHELL-SIDE TWO PHASE FLOW CHARACTERISTICS
    Yang Xiaoqiong,Wang Qijie,Li Wei and Luo Laiqin(Department of Power Machinery Engineering, Xian Jiaotong University, Xian 710049)
    1994, 45(3):  313-320. 
    Abstract ( 516 )   PDF (385KB) ( 129 )  
    Related Articles | Metrics
    This paper presents experimental results on the effect of fluid properties on two phase flow patterns,flow pattern transition equations,void fraction and two phase frictional pressure drop in the shell- side of a segmentally baffled shell- and- tube heat exchanger. A comparison between the air- water and air- diesel oil data shows that the liquid viscosity and interface tension produce a significant effect on the transition from intermittent flow to annular flow,a slight effect on the transition to bubble flow,and a significant effect on void fraction and two phase frictional pressure drop.
    SYNTHESIS OF DISTILLATION SEQUENCES WITH MULTI-FEED BY USING AN INDIVIDUAL MATERIAL ALLOCATION DIAGRAM
    Liu Zhiyong, Guo Zhushan and Chen Zhichuan( Department of Chemical Engineering,Hebei Institute of Technology ,Tianjin 300130)
    1994, 45(3):  321-326. 
    Abstract ( 481 )   PDF (307KB) ( 156 )  
    Related Articles | Metrics
    An Individual Material Allocation Diagram(IMAD) method was proposed to represent a distillation process with multi - feed. A synthesis procedure based on IMAD for distillation sequences with multi - feed was further proposed. In the synthesis procedure the order of separation was determined according to some heuristic rules proposed in this paper. The quantities of the process streams and bypass were represented by IMAD. An example was given to illustrate the synthesis procedure.
    EFFECTS OF POROUS STRUCTURE ON COAL PARTICLE REACTIVITY OF COMBUSTION
    Chen Hong, Sun Xuexin,Han Caiyuan and Cui Heping(National Coal Combustion Laboratory,Central China University of Technology, Wuhan 430074)
    1994, 45(3):  327-333. 
    Abstract ( 534 )   PDF (352KB) ( 213 )  
    Related Articles | Metrics
    Based on shapeless pore model (SPM) proposed by the authors, the equations of heterogeneous combustion kinetics, mass transfer, heat transfer,continuous momentum conservation of flow, which controll coal particle combustion were given. Numerical calculation of single particle combustion was made,and the effects of porosity,pore area, particle size and temperature on reactivities of chars were studied. It was found that ignition was heavily related to pore area ,and was less related to porosity. The results were compared with the data of Smith. It was shown that SPM could be applied both to coal particle combustion and to heterogeneous reaction of other porous materials.
    DESCRIPTION OF TRANSITIONAL FLUIDIZATION PATTERNS
    Liu Dejin, Li Hongzhong, Li Lianxuan and Zhang Jianguo(Multi - phase Reaction Laboratory, Institute of Chemical Metallurgy, Academia Sinica, Beijing 100080)
    1994, 45(3):  334-341. 
    Abstract ( 566 )   PDF (415KB) ( 254 )  
    Related Articles | Metrics
    Intermediate state fluidization is represented by a fuzzy set. One parameter, heterogeneity, deduced from statistical characteristics of fluidization voidage spectrum and εmf,is defined as the membership function of the fuzzy set. Interpretation by fuzzy sets of gas- solid and liquid -solid fluidization experiments under various pressures,fluid viscosities and particle properties, illustrates that the configuration of two - phase structure in fluidized bed varies with operating parameters as well as material properties. By means of fuzzy sets,the heterogeneity,or the grade of aggregative,of a certain fluidization state can be referred to as a specific number ranging from 0 to 1.
    SIMULATION AND CATALYST DISTRIBUTION OPTIMIZATION IN FIXED-BED REACTOR FOR ACETOXIDATION OF ETHYLENE
    Zhao Zhenxing, Li Ruili and Chen Gantang(Zhejiang University Branch,UNILAB Research Center of Chemical Reaction Engineering,Hangzhou 310027)
    1994, 45(3):  342-349. 
    Abstract ( 602 )   PDF (370KB) ( 154 )  
    Related Articles | Metrics
    The industrial fixed- bed reactor for acetoxidation of ethylene was math- ematical-ly simulated by pseudo- homogeneous one- dimensional and two- dimensional reactor models. The results showed that the gas temperature at the entrance of the reactor was close to the temperature of hot - spot, and that the activity of catalyst and productivity of reactor could be further increased. But,thermal runaway for a normal reactor may occur when the activity of catalyst was three times that of the present catalyst. The optimal distribution of a high active catalyst multiple- sectionally loaded in the reactor may greatly reduce the sensitivity of heat and may improve the conversion and selectivity of the reaction. For example,if a catalyst with mean activity two times that of the present catalyst was loaded in the reactor in two sections to replace the normal reactor loaded in one-section of catalyst,the temperature of hot-spot may be reduced by 13. 9℃ ,and the conversion of ethylene and the selectivity of vinyl acetate from ethylene may be increased by 1. 46% and by 1. 41% respectively.
    PHASE EQUILIBRIA OF PROPANE - ETHANOL - WATER SYSTEM
    Feng Yaosheng, Li Maokang and Hou Yujun(Department of Chemical Engineering,Zhejiang University ,Hangzhou 310027)
    1994, 45(3):  350-356. 
    Abstract ( 535 )   PDF (311KB) ( 199 )  
    Related Articles | Metrics
    A modified DDLC-MH(81) equation of state was proposed to correlate binary vapor - liquid equilibrum data in literature for a propane - ethanol - water system. The binary interaction parameters were linear functions of temperatures. The vapor - liquid equilibrium data for the binary and ternary systems were determined by means of a circulation apparatus. The experimental results were in good agreement with predicted results by using the model. Then the phase behavior of the ternary system under supercritical propane condition was predicted. The results showed that the solubilities and selectivities of ethanol solutions by using super - critical propane as solvent were better than supercritical carbon dioxide under the condition that the ethanol mole fractions in liquid phase were more than 0. 2.
    PARTICLE DIFFUSION IN TURBULENCE
    Wang Changan and Jiang Peizheng(Department of Chemical Machinery and Equipment,Xian Jiaotong University, Xian 710049 )
    1994, 45(3):  357-360. 
    Abstract ( 571 )   PDF (193KB) ( 357 )  
    Related Articles | Metrics
    A new equation of particle diffusion coefficient in turbulence was presented. It was compared with numerical simulation of particle diffusion in turbulence and the results calculated with Hinze- Tchen equation and Govan equation The equation agreed with the numerical simulation very well on the conditions that the relaxation time of particle is greater then the turbulent characteristic time scale and the settling velocity of particle is less than the fluctuating velocity of turbulence. The Hinze- Tchen equation was applicable only when the relaxation time of particle was less than the turbulent characteristic time scale, and the Govan equation was useful only when the settling velocity of particle was much greater than the fluctuating velocity of turbulence.
    GRINDING - DEMULSIFICATION EFFICIENCY AND ITS EMPIRICAL FORMULA
    Chu Ying, Liu Peiyan, Wu Zisheng and Yan Zhong(Chemistry Department of Northeast Normal University,Changchun 130024)Song You(Zhangjiakou Higher Agriculture Training School, Zhangjiakou 075131)
    1994, 45(3):  361-365. 
    Abstract ( 598 )   PDF (202KB) ( 123 )  
    Related Articles | Metrics
    In this paper the mechanism is studied on a novel technique of grinding - demul -sification developed by the authors. The main factors influencing grinding - demulsification are converted to a relation of demulsification efficiency and the collision in unit volume. An empirical formula for calculating demulsification efficiency is established from the experi -mental results.
    EQUATION OF SOLUTE REJECTION RATE IN REVERSE OSMOSIS PROCESS
    JI Chaoqing(Gansu Institute of Membrane Science and Technology,Lanzhou 730020)
    1994, 45(3):  366-370. 
    Abstract ( 574 )   PDF (223KB) ( 142 )  
    Related Articles | Metrics
    The transfer equations of solute and solvent in membrane are derived in this paper. If the permeation flux of solute is constant,the velocity of solute molecules should not be constant. There are some problems arising from the force equilibrium of friction model and surface force -pore flow model, i. e. the assumption of constant permeation flux of solute does not agree with the force equilibrium conditions. On the basis of the model of membrane adsorption diffusion, the equation of solute rejection rate is derived to describe the case of preferential adsorption of solute and solvent. When the mass transfer coefficient of the high pressure side of membrane k approaches infinity, solute rejection rate is independent of membrane thickness. The first order approximation of the equation of solute rejection rate is similar to the equation of solute rejection rate in Sourirajan theory and solution diffusion model. When the solvent is adsorbed preferentially on the membrane surface, solute rejection rate increases as feed speed increases. When the solute is adsorbed preferentially on the membrane surface, solute rejection rate decreases as feed speed increases.
    RHEOLOGICAL BEHAVIOUR OF MYCELIAL SUSPENSIONS OF POLYSTICTUS VERSICOLOR DURING CULTIVATION IN AN INTERNAL AIRLIFT-LOOP REACTOR
    Zhou Shaoqi(Department of Food Engineering,South China University of Technology,Guangzhou 510641)Feng Pusun and Tang Limin(Dalian University of Technology,Dalian 116012)
    1994, 45(3):  371-374. 
    Abstract ( 474 )   PDF (195KB) ( 128 )  
    Related Articles | Metrics
    Suspended mycelia of polystictus versicolor was cultured in an internal airlift- loop reactor with medium based on bean extract. A set of refitted NDJ- 2G type of rotating cylinder viscometer was used to measure the rheological properties of mycelial suspensions. The rheological equations were obtained by regression analysis. The results showed that the mycelial suspensions may have yield dilatant behaviour. The factors affecting its rheological behaviour were also discussed.
    CALCULATION OF PROPERTIES OF pVT AND ENTROPY FOR REAL GASES BY USING BH PERTURBATION THEORY
    Zhao Xiaoming, Zhao Guanchun and Song Xiaoming(Department of Power Machinery Engineering, Xian Jiaotong University, Xian 710049)
    1994, 45(3):  375-379. 
    Abstract ( 483 )   PDF (197KB) ( 108 )  
    Related Articles | Metrics
    The pressures of normal gases, hydrocarbons, freon, ammonia and water in the superheated rapor region and the entropies of normal gases, hydrocarbons, freon which dose to the saturated vapor line were calculated with perturbation theory. The calculated results were in good agreement with the values reported in literature, which also showed that the calculating method is of certain generality and practical value.
    ADSORPTIVE SEPARATION OF FLUOBORATE ANION IN A FOAM COLUMN
    Wang Juan and Chu Jiaying(Chemical Engineering Research Center, East China University of Science and Technology, Shanghai 200237)
    1994, 45(3):  380-384. 
    Abstract ( 489 )   PDF (247KB) ( 227 )  
    Related Articles | Metrics
    A foam column was used for removing fluoborate anion. The removal rate of fluoborate anion was measured. It was found that Dodecylamineacetate (DAAc) could be used as a carrier, and its concentration, gas flowrate and pH value of the solution were some significant factors of the separation effect.