Isothermal P-x data tor the binary systems methanol-methyl methacrylate and methanol-water, and isothermal P-x’-x" data for the binary system methyl methacrylate-water have been determined at 25, 35, 45, 55 and 60℃. Based on the maximum likelihood principle, the modified UNIQUAC model pa rameters for these binary systems were obtained by fitting the experimental data. Vapor compositions were then calculated, and the results were compared with literature data.

Isothermal P-x data for homogeneous, and P-x’-x" data for partially miscible mixtures for the ternary system methanol-methyl methacrylate-water have been determined at 25, 35, 45, 55 and 60℃. By using a modified UNIQUAC model and binary parameters only, the predicted ternary phase equilibrium data were found to be in good agreement with the experimental results, indicating the adequacy of using binary model parameters in computing vapor-liquid and liquid-liquid-vapor equilibria covering pressures ranging from reduced to atmospheric.

Dense phase voidage can be estimated by cutting gas flow and following the rate of bed collapse. Abrupt cessation of flow is not possible when excess gas in the windbox can only discharge through the bed. The magnitude of this problem is examined experimentally.

The global reaction rates for industrial high-temperature shift reaction catalyst WB-2, cylindrically shaped and measuring φ9×7mm, have been investigated in an internal-recycle gradientless reactor at pressures of 7×10~5 and 13×10~5 Pa (gauge). The pore-size distribution and the tortuosity factor have also been measured.in this part of the paper, by using the intrinsic kinetic equation obtained at atmospheric pressure for conditions under pressure, the numerical solutions of the effectiveness factors for 17 groups of experimental data of the global rates have been computed according to the simplified multieomponent diffusion model presented in the second part of the paper, and the results compared satisfactorily with experimentally observed values. It is therefore proposed that experiments for globdl rates under pressure would not be necessary for investigating the kinetic behavior under pressure for reactions for which the operating pressures are not too high such as the case for high-temperature shift rcaction.

Radial profiles of local gas and solid holdups and liquid interstitial velocity were measured in a largediameter three-phase fluidized bed, and a systematic study was carried out in comparing the present data with those obtained in small-diameter beds. Radial profiles of local gas holdup were found to be parabolic; the distribution of local solid particle holdup could be expressed by Eq. (9); liquid interstitial velocity was well described by the modified circulating flow model.

The kinetics of phase transfer catalyzed (PTC) disproportionation of elemental sulfur was studied in the range of OH~- concentrationlin the aqueous phase from 0.02 to 0.14 mol/dm~3 and temperature from 45 to 70℃. A kinetic expression, R_sa=k*[Q~+]_(aq)[OH~-]_(aq)[S]_(org)~(1/2), derived from the theory of mass transfer with rapid chemical reaction in liquid liquid system can be adopted to correlate the experimental data, and the apparent activation energy of the reaction was found to be 79kJ/mol. Kinetic evidence for PTC reaction of the system was given and a mechanism of PTC disproportionation of elemental sulfur was proposed.

Under atmosphe()e press()ne, rates of deseption of CO() from unmod()ed carbonated potash solutior (27 wt%)and modified carbonated potash solution(27 wt%) containing DETA as a catalyst, have been measured in a laboratory stirred reactor. Experiments were carried out with concentrations of DETA from 0—40g/L and temperatures from 90—104℃The results, show that the desorption of CO_2 from hot carbonated solutions with and without the addition of DETA, may be considered a pseudo-first order reversible reaction, and that the desorption of CO_2 from carbonated potash solution calalysed by DEIA is in agreement with the mechanism of simultancous reactions of CO_2 with amine molecules and with hydroxyl ions in solution. Mathematical models for desorptions rate cocflicient have been cstablished, and optimum concentration of DETA is proposed.

Based on the group contribution method of Rihani and Doraiswamy, a program system has been set up for automatically analyzing structures and computing ideal gas heat capacities. The method was verifled by using evaluated literature data of 479 organic compounds. The assessment of its computing precision and applicability has been made and some new group parameters recommended.

Previous work on the optimal activity distribution in catalyst pellets for the nonisothermal A→B reactions is extended to the nonisothermal two-component reactions with the kinetics r=kc_A~(m_1)c_B~(m_2)/(1+K_Ac_A+K_Bc_B)~a and some concepts are generalized. It is shown that the optimal activity distribution is also a Dirac delta function. The optimal location depends on nonisothermal effect parameter βγ, concentration sensitivity parameter πand Thiele modulus φ. A criterion is derived to evaluate the optimal location whether within the pellet or at the external surface. The influences of both the increase of the active layer thickness and the deviation of the active layer location from the optimal location are analysed. The effectiveness factors of pellets are more sensitive to the location than to the thickness.

A model is presented for the charge and discharge cyele of a zine-redox battery, based on the available steady-state cell performance model. The cycling model makes use of a quasi-steady-state assumption and includes the effects of crystallization and membrane water transport on the volume of electrolyte during a cycle, as well as variable IR-drop due to conductivity changes. Performance predictions of this model are compared with selected experimental charge/discharge data. Small adjustments to the equilibrium cell potential and cell resistance are made to make the model suitable for design optimization.

The abvent of the ASOG and UNIFAC group-contribution methods for the prediction of activity coefficients approximately 15 years ago was a significant boost to the ability of chemical engineers to model chemical processes. This paper reviews the status and recent progress in the group-contribution approach to predicting liquid-phase activity coefficients.Several different types of liquid mixtures arc considered: non electrolyte mixtures with normal-boiling components; mixtures with dissolved gases; mixtures with polymers; and mixtures including strong electrolytes. It is concluded that in recent years much progress has been made in the development of group-contribution models for the prediction of activity coefficients. It is in addition shown that combining activity coefficient models with equations of state renders the group-contribution approach applicable also to the highpressure region.Due to space limitation, this review emphasizes UNIFAC and related models.

A nonlinear dynamic cascade model with varying coefficients has becn derivcd for a sixteen-stage countercurrent extractor representing the first cycle of a Purex process. This actually is the result of further scrutinizing of the process mechanism and following-up of a simple linear dynamic cascade model formerly developed. A variable step length floating-point linearization algorithm for solving the nonlinear dynamic cascade model is proposed. The dynamic distribution of extracted materials in different stages and their variation with time are disclosed. Experimental data seem to conform quite satisfactorily with theoretical values obtained from the sensitive stage theory.