A generalized method was presented for calculating the vapor-liquid equilibria of aqueous volatile weak electrolyte systems. By extending the KZ algorithm of simultaneous chemical and phase equilibrium calculations developed 玝y Xiao et al. (1989)to electrolyte systems with the electroneutrality equation being replaced by mass balance equations of ionic species, and splitting the complex system of dissociation reactions into two simple ones, the present approach showed better efficiency than those developed by Sanderson and Chien (1973) and by Gautam and Seider (1979). The calculated results agreed well with the experimental values.

A continuous two-membrane column consisting of silicone rubber capillaries and cellulose acetate hollow fibers was used for the separation of binary gas mixtures. The extent of separation in the column was studied under different conditions. A mathematical model was established for the separation of binary gas mixtures in the two-membrane column. The new model proposed was compared with other known models and was verified with experimental data.

The gas hold-up characteristics of a downflow liquid jet loop reactor were studied with Newtonian and non-Newtonian fluids. The optimum ratio of draft tube to reactor diameter was found to be about 0.57. A theoretical model was obtained by solving the equation of motion. The prediction of gas holdup with the model agreed with the experimental data. These results could be useful for design and scale-up purposes.

The selectivity coefficient of the system, L-Lysine/ammonium type sulfonic cation-exchange resin, was determined and its kinetic studies showed that it is particle-diffusion controlled. A method based on the Vermeuten method, was proposed for the calculation of the fixed-bed ion-exchange column under the constant-pattern mode. The method was proved to be in good agreement with the experimental results and could be used for the design of the L-Lysine ion-exchange column.

The kinetic models of aqueous polymerization for acrykmitrile was established in terms of its polymerization mechanism and granulation mechanism. Two kinetic models of polymerization, corresponding to micromixing and macromixing respectively, were developed on the basis of the Danckwerts-Zwie-tering micromixing theory. The experimental data of conversion and number-average molecular weight, obtained from a continuous stirred-tank reactor, were used to check the two models. It was found that a micromixing kinetic model is more suitable for describing the process of acrylonitrile continuous polymerization in aqueous medium.

The model used as the basis for the calculation of nucleation Kinetics from measurements of the widths of the metastable zone was refined. Metastable zone widths, represented by the critical under-cooling at which crystalline particles being first detected, were determined for the aqueous solution of sodium tetraborate decahydrate (borax) by using an apparatus equipped with computer and laser measuring device. The effects of trace amounts of n-pentane in the solution on the solubility and metastable zone width were investigated. Nucleation parameters were obtained and discussed in terms of the refined model.

Investigation of heat transfer and flow resistance of tubular gas-gas heat exchanger with contracted-expanded tube bundles and spiral fluted tube bundles and air flowing parallel to tube bundles in the shell side is reported. Comparison of heat transfer performance was made between this type of tubular gas heat exchanger and the segment baffled tubular gas heat exchanger under the same conditions of total gas pressure drop in the tube and shell sides, total volume flow rate, temperature difference and rate of heat transfer. The results showed that the total heat transfer coefficient K of gas heat exchanger with contracted-expanded tube bundles was 64.8% higher than that of segment baffled tubular gas heat exchanger, and 40% of heat transfer surface area could be saved.

In this paper, the effect of activation procedure in butane-air mixture on the performance of Vanadium-Phosphorus-Oxygen catalysts for oxidation of "butane to maleic anhydride are systematically studied. The catalysts were characterized before and after activation by XRD, IR, TEM, SEM, EPMA and specific surface area determination. Experimental results indicated that activation procedure had an obvious influence on the phase transformation (precursor→ amorphous phase→(VO)2P2O7→β-VOPO4), specific surface area and surface phosphorus/vanadium ration of the catalyst. The morphology of catalysts remained unaltered during activation, but the platelets graduall ybacame smaller. It was shown that vanadyl pyfophosphate ((VO)2P2O7) is the active phase of the catalyst and the catalytic properties are related not only to surface area, but also to the phase composition. Furthermore, a catalyst containing primarily the active phase (VO)2p2O7 was obtained under appropriate activation condition. This catalyst exhibited high activity and good selectivity to maleic anhydride and approached to a steady activity in a short time.

In this paper, the heat conduction of freezing of liquid in pipe was analyzed. The methods of transforming variable and equivalent heat capacity were used for calculation respectively. A new calculation method was used with the transforming variable method for one dimensional variable problems. The calculated values agreed well with the experimental and reported values. This method could be used for solving non-linear heat conduction problem involving latent heat.

This paper describes the work done on experimental measurements andmathematical modeling of solid particle concentration distribution in a three-phase gas-lift loop reactor. Air, water and sea sand were used as the experimental system. The distribution curves of solid particle concentration in the annular space and in the bubble layer above the top of the central tube were measured with a fibre optic sensor. A mathematical model for the axial distribution of solid particles in the annular space and an empirical model for solid particle concentration distribution in the central jetting zone of the bubble layer were derived respectively: The results calculated with these models were found to be in good agreement with the measured results.

An effective temperature dependent function for the a expression was used to modify the Peng-Robinson equation. The ETDF-PR equation was used for vapor-liquid equilibria calculations for 52 pure substances, including non-polar, quantum, and polar fluids. The calculated vapor pressures were compared with those from several conventional equations of state. The results showed that this work is a good improvement, in particular, for the polar fluids and the higher alcohols of interest.

The ETDF-PR equation of state proposed in Part( I )of this work was extended to the vapor-liquid equilibria of mixtures. A comprehensive mixing rule and fugacity coefficient expression were proposed, which can be simplified into different versions for the specific systems. Binary and ternary VLE for nonpolar-nonpolar, nonpolar-polar, polar-polar systems (mainly alcohol-containing systems) at moderate and high pressures were calculated with satisfactory accuracy. Moreover, a method to handle the supercritical component for the ETDF-PR equation was presented, and used for hydrogen-containing systems successfully. In conclusion, a practical procedure for describing VLE for complex systems was suggested in this work. Apparently, this procedure can be applied to the process development for the separation of the higher alcohols and other real systems.

The principle of chemical engineering was applied to drug delivery. Am unsteady-state delivery kinetics model with boundary diffusion layer resistance was established to replace the "Pseudosteady-state Assumption" which deviates from the real delivery process. A novel poly (ethylene-vinyl alcohol)/vitamin B12 slab delivery system was designed and used to verify the model. The results showed that the model was effective in describing and predicting the delivery behaviors for a diffusion-controlled polymer/drug release system.

The heat and mass transfer in the sublimation problem of a Ficks porous slab under the first boundary condition was studied by the use of perturbation method. From a new treatment of the boundary conditions at the moving interface proposed by the authors, the analytical expressions of the dimension-less temperature, concentration and the position of moving interface could be developed. The pertur bation solution approached the experimental results better than the quasi-steady model.

This paper aims at developing a rigorous method for determining minimum reflux ratio in the distillation of "tangent systems" which are defined as those with concave VLE curves. Two pinch zones in the rectifying or stripping section may be obtained with previously published models when different initial values are chosen. This behavior naturally leads to the fact that the calculated minimum reflux ratio could be lower than the "real "one. On the basis of Chiens method, the authors used parabolic interpolation to acquire the maximum condensor in the two pinch zones and then find out the "real" minimum reflux ratio. The results were verified and showed adequate precision. The algorithm presented in this paper can be used not only for tangent systems, but also for conventional distillation systems.

The kinetics of cobalt extraction with extractant 5709 (Hexyl-phosphonicAcid Mono-1-Methylheptyl Ester )-Heptane-CoSO4-H2SO4 system was studied with a modified constant interface cell. The extraction kinetics was found to be a mixed controlling regime, i. e., diffusion of cobalt in aqueous phase and chemical reaction of the diffusion of 1 - 2 complex of cobalt at the interface. At higher pH, diffusion was the dominant step, at lower pH, the formation of complex was the dominant step. A mathematic model was established as follows: The apparent activation energy E thus calculated as 8.57 kcal/mol, also sup-ported the mixed controlling regime oi the extraction kinetics ot cobalt.

In this paper the pressure drop ot condensation on the shell-side of ROD-baffle condenser is analyzed. The simple expressions tor calculating pressure drop through the shell-side of the condenser were proposed. They were verified by an experiment, in which saturated vapor ot solvent naphtha condensed on the shell-side of ROD-baffle condenser, and by an industrial experiment on the consensation of naphtha-vapor on the top of a primary tower. It was proved that the method mentioned is reliable.

A new π-type static mixing element developed by the authors was tested for its fluid dynamics and heat transfer performance. The test results were compared with those of the Kenics element. The π-type element was shown to be effective in enhancing heat transfer.