The characteristics of a staged bubble column can be described by a multistage backmixing model, provided: (1)Each stage can be considered as a perfect mixing reactor, and(2)The backmixing coefficients do not vary with time and reagent concentration. Experimental results indicate that the first condition is approached under certain conditions, while the second assumption is correct. Studies were made using steady state chemical tracer method to determine the backmixing coefficients of each plate between stages. The fluid flow through the holes of perforated plates is a stochastic process. From the statistical point, the experimental data could be correlated by a semiempiri-cal equation developed. This equation can also be used to correlate the data reported by Nishiwaki et al. for bubble column with plates having high percentage of opening area and large sized holes between stages. Continuous oxidation of unsaturated sulfur compounds (mainly in the form of S2O3= and also some in S3O6=, S4O6=etc. polythionates form) in nickel ammonium carbonate solution were carried out in bubble column with height of 3400mm and diameters of 36mm and 100mm respectively. The oxidation has to be taken in a multi-stage bubble column for high degree of oxidation. The concentration of unsaturated sulfur compounds along a multi-stage bubble column can be calculated from the backmixing model and the kinetic equation of oxidation. The results of calculation agree with the data taken along the column. Equation was also developed to calculate the optimum temperature of oxidation which agrees favorably with the experimental results.

For a determined mathematical model, it is not only necessary to obtain the estimates of parameters, but also their reliabilities. The present work deals with a sequential statistical design strategy for an experimental program to obtain precise parameter estimates for a nonlinear kinetic model. It aims at decreasing the indeterminatness of the parameter estimates, in reducing the correlation between parameter estimates, and in increasing the adequacy and accuracy of the model. The paper discusses the experimental design criterion for precise parameter estimates-the minimun volume design criterion and the spherical shape design criterion, and the practical value of a sequential statistical design strategy. At last, an example was performed to precise estimate the parameters in the kinetic model of ammonia synthesis reaction which was selected as being adequate in the previous work. Comparison of the results from the industrial unit and the corresponding values calculated with the model using the estimates of parameters reveals the reasonable reliability of the model.

The gas flow characteristics, the ideal sealing state without gas passing through and the solid flow rate in a vertical moving bed under negative pressure difference were studied in this paper. The correlated equations were obtained based upon the experimental results of three kinds and four standards of particle materials. A discussion was made about the gas-solid flow further and a method was suggested to select and design the sealing height in a moving bed reasonably.

The study of the relationship of vapor liquid equilibria in the acryloni-trile-acetonitrile-water ternary system is based on a large number of experimental data. The multiparameter Wilson equation is used to correlate the vapor-liquid equilibrium data.The parameters in above equation are wholly provided from corresponding binary systems. The total average absolute arithmatic deviation of 99 data points is only 0.0098 mol fraction. It must be pointed out that this result is considerable successful in such non-ideal and partially miscible ternary system. The conjugate points of liquid-liquid equilibria can be correlated by using the same relationship, and quite good results can also be obtained. On the basis of this relationship, we plot a series of curves, such as the curves of vapor-liquid equilibrium compositions, the curves of normal boiling point of solutions, the relative volatilities of acrylonitrile to acetonitrile at different contents of water. These curves can be used easily and efficiently in design calculations.

The transmission of radiant heat in the tubular furnace has been studied. A new method of calculation is developed and a mathematical model is formulated. By means of this mathematical model, the heat of transmission for modern cracking tubular furnaces, heater of box type and cylindric heater can be solved more correctly. The new mathematical model for cracking tubular furnace is as follows.The mathematical model is derived from a new concept i. e. the flame-wall emissivity gw. Other types of mathematical models already in use are also discussed. As an example for illustration, six modern cracking tubular furnaces are calculated with the new method. The calculated and actual values are in agreement quite well. It is shown by these results that the proposed new model may be used in practical engineering calculations.

The hydrodynamics of perform trays were studied using air-water system in a column with a 1200 x 400mm rectangular cross section to determine the effect of tray geometrical parameters and operating conditions on the pressure drop, entrainment and weeping. Geometrical variables and operating range were mainly as follows: slot widths, 3, 3.5, 4, 4.5 and 4.7mm; tray free areas, 9.9, 12.3, 14.9 and 15.4%; deflector widths, 150, 200, 250 and 300mm; tray spa-cings, 400, 500, 600, 700 and 800mm; liquid flow rates per unit weir length, 20, 30, 45 and 60m3/m.h; and superficial gas velocities, 0.60 to 2.8m/s. Experimental data were correlated and correlations were presented for calculating the pressure drop, entrainment and liquid weeping. Furthermore, based on the experimental results for the entrainment and weeping from the tray,the expressions were given also to predict the upper limiting hole velocity at which the entrainment from the tray is 10%, the lower limiting hole velocity at which the liquid weeping from the tray is 5%. In addition, the effect of inlet weir on the weeping were tested and a simiempirical model was derived for the inlet weir design. These correlations, as mentioned above, can be applied to the design of perform trays.

A recirculating still specially designed for partially miscible systems was used for the determination of isobaric vapor-liquid equilibrium data at 760 mm Hg for the n-butanol-isobutanol-water system. For the determination of solubility at the boiling point the cloud point titration method was used. The vapor-liquid phase equilibrium data and solubility data at boiling point for the ternary system under study have been well correlated by the modified Wilson equation proposed by Mitsuyasu. The NRTL and the Uniquac equations were also used for the correlation of the vapor-liquid phase equilibrium data. All the above correlations are adequate for design purposes.

An internal recycle gradientlebs catalytic reactor devised by The Chemistry Department of Sichuan University was used in the kinetic study on catalytic steam reforming of natural gas at high temperature and moderate pressure with satisfactory results in fitting data for kinetic equation, measuring internal surface utility factor of catalyst pellets and simulating point conditions of catalytic reactor of commercial size.