For the one-dimensional catalyst pellets, the perturbation method can be employed to get asymptotic solutions of isothermal heterogeneous diffusion-reaction equations with arbitrary kinetics when Thiele moduli are small or large. From the asymptotic solutions, a new analytical expression of effectiveness factor valid throughout the whole range of Thiele modulus is obtained. Compared with the exact analytical solutions of first order irreversible reaction, the approximate solutions are satisfactory in a larger scope.

According to the approximate analytical expression for effectiveness factorpreviously proposed by the authors, a great deal of calculations are made with power law type kinetic expressions and Langmuir-Hinshelwood kinetic expressions for three onedimensional catalyst pellets. The results show that our approximate solutions agree fairly well with the exact values obtained by numerical method in all circumstances investigated. The comparison with other approximate expressions in literature is made. As our expression is based on the analysis of the characteristics of the reaction system, the exactness is higher, the calculation is much easier, and above all, its scope of application is wider.

A molecular thermodynamic model of gas solubility in nonpolar solvents has been established. The Helmholtz energy of liquid mixture is calculated through the following three steps. First, the pure components in standard state are mixed isothermally to form an ideal gas mixture. Then each molecule is inflated into a hard sphere with diameterσ. The corresponding Helmholtz energy change is calculated by using the Mansoori-Carnahan-Starling-Leland equation. Finally, the molecules are charged with LJ 12-6 potential to form the real liquid mixture, where the structure is described by an approximated radial distribution function gij(r) = H(r-rij**) + βδ(r-rij*). Henrys constants are then calculated from residual chemical potential. With the use of the same LJ parameters,this model can predict the computer simulation results of Henrys constants quite well. In this respect, this model is superior to the Pierottis theory. For the practical systems, using only one adjustable parameter, the Henrys constants of various gases in C1-C20 alkanes and their isomers, naphthenes, aromatic hydrocarbons and liquid gases can be well correlated over a wide temperature range. The predictions for A△Hs1, △Ss1, and V1 are satisfactory either.

In this paper, a modified version of Castillo-Grossmann method for calculating multicomponent miltiphase equilibria is presented, which is based on the principle of minimizing the Gibbs free energy of the system. This modified method has been tested on 14 examples, including ideal and non-ideal systems. In each example several different conditions were involved. The results showed that the modified version converged much faster than the original method.

Based upon the conjugate gradient projection algorithm of nonlinear programming, a new general method-GCG was constructed with two treatments according to the peculiarity of chemical equilibria calculation. The first treatment was that a special relation between iteration and linear searching was set up, according to the ideality of the system. The second was that a method of determining the initial active set in algorithm was designed for equilibria problems. The results of calculation showed that for most non-ideal systems, it was very efficient.

A mathematical model for complex systems of interlinked distillation columns is presented. Because of the presence of interlinked streams, a small number of nonzero off-tridiagonal elements occurred in the blocks matrix and consequently complicated the procedure of solution. The method presented in this paper adopted the basic procedure developed by Browne for solving multicolumn equilibrium stages, and improved his convergence criteria. In order to make use of mass storage efficiently during the solution, the e-limination form of inverse(EFI) and product form of inverse(PFI) were used, so as to provide the possibility for solving large-scale problems. Examples cited from the literature were calculated with satisfactory results.

The effect of intraparticle diffusion of catalyst has been investigated in a flow-recirculation glass reactor. The reaction of oxidative dehydrogenation of butene-2 occurred in the kinetic regime over 30-40 mesh Mo3.0 Bi0.9Ce1.1/ SiO2 catalyst. When the particle size of catalyst increased to 5-14 mesh, the reaction of oxidative dehydrogenation of butene-2 occurred in the regime of intraparticle diffusion. The effect of intraparticle diffusion of catalyst increased with the rise of reaction temperature. At 753K, the measured value of catalytic effectiveness factor was 0. 20. The effects of intraparticle diffusion on activation energies of reduction of catalyst by butene-2 and reoxidation of reduced catalyst were measured experimentally. The value of activation energy for butene-2 when intraparticle diffusion controls, is equal to the mean of the activation energy in both the kinetic and the diffusion regime. The effects of intraparticle diffusion on the selectivity of butadiene were investigated. An empirecal equation was set up to represent the effects of intraparticla diffusion on the selectivity of butadiene.

Volumetric liquid-phase mass transfer coefficients as well as gas-liquid interracial area for oxygen-water and oxygen-aqueous-C7F15 COONa-solution systems were determined in a horizontal stirred vessel by steady-state oxygen absorption and light scattering experiments. The horizontal agitated ves-sel is considered to possess more advantages than the vertical vessel, such as lower agitation speed tor normal gas-liquid mass transfer, greater kLa for the same agitation power, improved mixing, and homogeneity in mass transfer area distribution. The paper deals with differences of mass transfer characteristics between these two types of vesseis on the basis of hydromechanics, and gives correlations of the experimental results The objective of the paper is to provide basic data tor developing processes for manufacturing fluorine-containing polymer.

A new generalized correlation tor the estimation of heat capacities of liquid organic compounds has been developed. It is applicable to many types ot organic compounds including the strong polar and associated compounds and to the temperature range from the reduced melting point Tm, to the reduced temperature of 0.95. The heat capacities of 103 compounds, have been calculated with this method and compound with data of 1567 points, and an absolute average deviation of 3% has been obtained for all types of compounds except acids for which it has been shown to be 5%. The results are better than those of published methods.

On the basis of the generalized cubic equation of state proposed by Abbott, the author put forward a two parameter cubic equation of state which is universally suitable for fluids.Within the range of Pr = 0-30, and T = 0.5-15,when the new equation of state was tested on 400 data points, 90.5% of the points has an error of less than 4%.Comparea to other two-parameter equations of state, the new equation has the advantage of accuracy and simplicity.

Based on absolute-rate theory, a new equation has been derived to correlate the binary liquid diffusion coefficient with concentration: where Cv = (FAAVBB/V)1/3, Cn = (). It has been applied to 16 systems with 176 experimental points. The grand average percent deviation in comparison with those obtained by using three other equations is as follows The results of calculation show that the equation proposed has higher generality and better applicability.

This paper studies the condition for criticality and some related problems for the stationary-state of the continuous-flow stirred tank reactor(CSTR) under non-adiabatic operation with heat loss through its wall. Dimension-Jess parameters may be used in analysing the thermally sensitive region in order to reduce the problem to the same form as that for the simpler adi-abatic CSTR. Mathematical expressions for the two important thermally sensitive boundaries of ignition and extinction are derived. And it is also shown that when the thermally sensitive regions disappear. Because the left-hand side of the above relation contains parameters that are easily controlled, this relation possesses practical importance in chemical engineering design and control.

This paper proposed an unsteady-state physical desorption method for determining gas-liquid mass transfer coefficients on trays. The advantages of this method are ease for experimentation and accuracy of results. Mass transfer coefficients on different sieve plates were measured at various gas flow rates. By using the equation for the efficiency of sieve trays without downcomers, the dimensionless variance of liquid residence time distribution on the tray was calculated.

The objective of this work is to determine the conditions for sepa rating Co2+ and Cu2+ from Ni2+ in mixed acid(HCl-H2SO4) with N235(Alamine 336)as an extractant. The distribution coefficients of Ni2+, Co2+ and Cu2+ were measured under different conditions, and on the basis of the distribution coefficients obtained, equilibrium models for the three elements have been established by nonlinear least square method. These models were tested in a four-stage countercurrent extraction battery. The test results showed satisfactory agreement between models andmeasred.