A two-parameter model (TPM) for determining the effective diffusivities (De) in porous solids has been proposed. The model is applicable to monodis-perse and/or bidisperse pore systems. The resultant expression ot the model for De may be written as: where w and are adjustable model parameters, evaluated from steady or unsteady state diffusion measurements and independent of pore-size distribution and other textural data. Applying TPM to the results of steady and unsteady state diffusion measurements in literature and this article, it is found that the parameters are independent of measurement conditions such as carrier gas, tracer, temperature and pressure. It is concluded that TPM serves well as a reflection ot the textural characteristics of porous solids.

Mass transfer experiments have been carried out in a 40mm diameter pulsed extraction column equipped with standard and "dispersion-coalescence" type cartridges; respectively. A system with 30% TBP (kerosene as diluent)/ HNO3/H2O was used. "True" volumetric mass transfer coefficient and back- m ixing parameters in continuous and dispersed phases were simultaneously evaluated from the steady state concentration profiles in both phases using a computer program based on the backflow model. Drop sizes and dispersed phase hold-up in the column were measured at the same time. Overall mass transfer coefficients were then calculated. It was shown that the mass transfer charicteristics of the extraction column can be predicted by the single turbulent circulating drop mass transfer mechanism.

Hydrodynamics in rotating perforated disk contactors (RPDC) have been studied with kerosine-water and emulsion-water systems. The effects of the contactor dimension and the two phase systems on the fractional hold-up X and the characteristic velocity u as well as the rotor speed at flooding nt have been studied. The contactor dimension factors investigated are: (1) the diameter of stator ring opening, (2) the diameter of the disk and the hole distribution on it, and (3) the hole size. Experimental results indicate that: (1)for a given system, when contactor dimension and rotor speed remain unchanged, the phase flow rates, the holdup and the characteristic velocity can be correlated by the semi-empirical equation proposed by logsdial: u + ucx/(1 - x) =uox(1 - x) (2) at slow rotor speed, RPDC has good liquid-liquid dispersion performance, as the rotor peripheral speed was about 0.5m/s, (only 1/3 of the critical rotor peripheral speed of RDC), the change of the fractional hold-up x andthe characteristic velocity uo with the rotor speed n was very pere This is due to the fact that holes on the rotor disk have good cutting ef on the dispersed phase drops that are going up through the holes, (3)the minimum rotor speed under which the holes can cut the dispersed phase drops may be calculated as tollows:

Disproportionate of elemental sulfur in tetrachloroethylene with aqueous hydroxide was found to be catalyzed by tetrabutylammonium hydroxide, and its reaction kinetics was investigated at a hydroxide concentration of 0.02-0.14 mol and within a temperature of 45-70℃. The linear dependence of the observed volumetric reaction rate Rsa on the rate of agitation within the range from 1.1.3 to 21.2 s-1 (680 to 1270 rpm), indicates the typical characteristics of a interfacial reaction, and within the range studied, Rsa can be expressed as The apparent activation energy was derived from experimental data as 79 kJ/ mol. The results of this kinetic study can be explained satisfactorily by a mathematical model of mass transfer with fast chemical reaction in liquid-liquid system. It indicated that disproportionation of elemental sulfur was first order with respect to both the hydroxide ion in the aqueous phase and sulfur in the organic phase. The reaction was supposed to be initiated at the interface and completed within the diffusion film in the organic side. Evidence of PTC from the experimental results was given, and a reaction mechanism was proposed and discussed.

A two-compartment model in a patient-hollow fiber artificial kidney system with ultrafiltration was studied. The model had taken into account not only the influence of ultrafiltration on the removal of the solute, but also the influence of extracellular volume changes withtime, thus bringing about universal significance. In the experiment, a dog was connected to the artificial kidney. A two-compartment model parameters wore identified with experimental data obtained, and satisfactory results were claimed.

Effects of the composition (Cu/Zn and Al) of a Cu-based catalyst for methanol systhesis on its structure and property have been studied. When the aluminium content is fixed at 20.7mol% in a Cu-Zn-Al catalyst for methanol synthesis, the structure of the catalyst precursor kept to be pure FC at Cu/Zn<= 3.6 and maximum activity oi the methanol synthesis will be obtained at Cu/ Zn=1.83. It is thought that the activity ot the catalyst depends highly on the optimum ratio between Cu and ZnO. If the Cu/Zn ratio is fixed at 1.83 with lower Al content, the structure of the precursors will turn out to be a mixing phase of FC and M. The presence of M would have great influence on the structure of FC and on the activity of the catalyst. A good catalyst formula tion(Cu:Zn:Al = 58.5;32.0:9.5) for methanol synthesis can thus be obtained. The role of aluminium is being discussed. Based on the characteristic structure of the paracrystallite, it is suggested that the active center for methanol synthesis is Cu-Zn, where □ is the oxygen vacancy.

A new liquid membrane system is established with a double carrier(TRPO, a mixture of trialkyl phosphine oxime, and HDEHP, bis-(2-ethylhextyl)phosphoric acid)membrane phase, basic inner aqueous phase and weak acidic waste water phase for the removal of Cd2+ and CN- simultaneously and the direct re-use of the concentrated Cd(CN)42- in plating tanks. In order to describe the matching of the transport rates of Cadmium and Cyanide in this system, a synchronous-transport concept is developed and mathematically presented to be the same form of the liquid membrane transport rate equations of the two transported species. These equations can be used as a guidance for the selection of the optimum operation condition for the separation process.

A multi-object optimization mathematical model with strict constraints has been developed for the heat recovery system in the first stage conversion furnace of large-scale synthetic ammonia plants (1000 t/day). Optimal synthesis was conducted through graphic solutions combined with optimizing calculations, employing the optimization theory for large complex system in system engineering Comparing with the original design, it was found that significant increases in heat recovery efficiency can be obtained with the new design scheme. Additional capital investment is not called for to adopt the new schema, neither would there be any increase in operating cost to achieve similar energy recovery as in the original design.

The mechanism of the anionic polymerization of butadiene and the quantitative relatioship of vinyl content versus the concentration of lewis bases including THF, DOX and Et2O were studied. Results obtained indicated that experimental data collected in the presence of the Lewis bases employed conformed with the quantitative relationship presented by the authors in their previous paper on this same subject. A complex equilibrium constant K and a coordination solvated index n were determined from the intercept and slope of the logarithmic equation at different temperatures. Moderate increases in reaction temperatures tended to bring about slight decreases in the values ot K and n. Quantitative relationships between K and/or n and temperature were obtained. A more generalized polymerization mechanism of butadiene was thereby proposed.

Experiments were conducted extensively for the flow field of a EPVC-IA Vane-guided cyclone tube developed by our institute, the three dimensional components of velocity and static pressure drops were determined. The configuration of the cyclone tube, especially the geometrical parameters of the split-flow core tube, was found to have great effect on the flow field. Mathematical models for ideal flows as well as for turbulent and viscous flows in this cyclone tube were derived from the basic equations of the fluid flow. A series of analytical solution of the three dimensional vortex flows in this cyclone tube were deduced and showed good agreement with experimental data.

The mathematical expressions for correlating the second virial coefficients for 166 pure substances with temperature are reviewed and selected. B = Be + B1/t + B2/t2 + B3/t3 + B4/t4, t=T/1000, and lg(-B)=E0 +E1(100/T) + E2lg(T/100) are recommended. Using the second virial coefficient data, Lennard-Jones parameters for the above-mentioned substances and Stockmayer parameters for 41 polar compounds are determined.

Let T (xi0) represent the temperature dependence (T) on the gravimetric mole fraction oi component i (Xi0) for the system within an ebulliometer or an equilibrium still operating steadily under constant pressure. We proved that the necessary and sufficient condition for the existence of maximun (minimum) azeotrope is(T/xi0)p |xi0=0>0(<0), i=1,2;and the maximun (minimum) azeo-tropic point coincides with the maximun (minimum) point of T (xi0). Similar conclusions are obtained tor the case of constant temperature.

Vapour-liquid equilibrium data(VLE) were measured in a Otsuki-Williams still at 9.866×104Pa.Analyses were made for the Ternary system HCOOH-CH3COOH-H2O and the quaternary system HCOOH-CH3COOH-H2O-NaAc in VLE(1mol/(kg solv. ))of NnAc was used. The results show that the favorable effect of NaAc is reflected not only in the chemical action, but also in the physicochemical aspect. This apparently is related to the phenomena of salting out, salting in and their anomalous behavior.

Based on a proposed model concerning the start-up process in multicom-ponent distillation with consideration of the hold-up in top, plates and re-boiler of the column as well as the plate efficiency, the computed result for a ternary system shows that the component concentration profiles in liquid during the start-up period are different in comparison with a binary system. Computations are confirmed experimentally by a pilot distillation column of 170 mm in diameter with methanol-ethanol-water ternary system.