The flooding point and hold-up of the dispersed phase in an extraction column with reciprocating-sieve plates of 32 mm inside diameter and 1960 mm effective column height have been investigated under the following conditions: Percent perforation of the plates 40%, 53.5% and 63.7%, diameters of perforated holes 7.8, 9.0 and 9.8 mm, and distances between plates 20 and 40mm respectively. Experiments were carried out with three different liquid-liquid systems covering a rather wide range of physical properties. The relative velocity of the two phases passing through the perforations of the plates is considered in the present work to be related to the work done by the oscillating plates in the column on unit mass of liquid in unit time. Therefore the flooding velocity and hold-up in extraction column with reciprocating sieve plates should be related to A2F3 instead of AF as reported before, where A is the amplitude and F is the frequency of oscillation. Equations were developed as shown below to correlate the experimental data of flooding point and hold-up respectively: Usf=5.95 and Where Usf and Vdf are relative velocity and velocity of dispersed phase at flooding point respectively in cm/s;φf, fraction of hold-up of dispersed phase at flooding point; ε, fraction of opening of plates; σ, interfacial tension in dyn/cm; AP, density difference between phases in g/cm3; h, distance between plates in cm and μc, viscosity of continuous phase in g/cm

The mathematical model of diffusion process in polarographic determination of dissolved oxygen has been thoroughly studied with an electric simulator. It is found that the combination of microelectrode and impulse operating technique is a possible way to improve the characteristics of present Clark electrode. The quantitative relations between the electrode size and operating condition are given in this paper in dimensionless form, and the range of the optimum condition has been discussed.

A modefied Newton-Raphson method is presented in this report. It consists of introducing relaxation factor ω, parameter α into general Newton-Raphson method. In convergence process, physical variables are updated reasonably in physically meaningful range, so they smoothlly converge to a solution. Examinations were made with nonideal distillation system. The results showed that the present method gave better convergence character than either Newton-Raphson or successive substitution approach.

The transfer of trivalent europium ion in a liquid surfactant membrane system was investigsted in order to clarify the characteristics of liquid membrane separation process and the availability of this technique for recovering trivalent lanthanides and actinides. The membrane phase consists of kerosene (solvent), Span-80 (surfactant) and di-(2-ethylhexyl) phosphoric acid (HDEHP, carrier). The internal phase is dilute nitric acid and the external phase is aqueous solution containing Eu(NO3)3 buffered by HAc-NaAc. Results show that the transfer rate of europium in this system is rather high and the recovery of europium may be higher than 99%. A multilayer structure model for emulsion globuls and the equations describing the change of effective membrane thickness during mass transfer are suggested. The resulting mass transfer flux equation is as follows: where Co: concentration of Eu3+, at t = t0, Ct: concentration of Eu3+, at t = t, V : volume of external phase, F: total mass transfer surface area, CH: initial acid concentration in internal phase, C : carrier concentration in membrane phase, D: diffusion coefficient of Eu3+-HDEHP complex in membrane phase, Experimental data show that l-(Ct/Co) is actually a linear function of and D calculated is about 1.1×10-6 cm2/s.

An experimental equipment was designed to measure the diffusion rate of gases through the ring-shaped, cylindrical or tabletted catalyst, using this equipment and the constant total pressure, steady-state technique, the tortuosity of Z-type natural gas steam reforming calalyst has been determined, with gas systems of CH4-He, N2-He and N2-CH4 at ordinary temperature and pressure. The results obtained for different gas systems quite close each other, the tortuosity of the catalyst is about 2.3.

Based on the production practice and previous researchs, this article investigates the poisoning process of fluorine compounds (HF and SiF4) on vanadium catalyst (carrier contains SiO2) in the manufacture of sulfuric acid. It offers that the poisoning process of vanadium catalyst by fluoride is chiefly due to the reversible transformation in the form of fluorine, i. e. 4HF + SiO2 SiF4 + 2H2O Using thermodynamic method to investigate the poisoning process of vanadium catalyst in sulfur dioxide converter, and to make a chemical equilibrium calculation about its reaction, the result from calculation reveals that in practical production it is generally poisoned by SiF4. Equilibrium conversion chart for HF→SiF4 and empirical formulas for calculating same conversion shown in this article can be used for quantitatively estimating the possibility of fluoride poisoning both in design work and in plant operation.

Liquid membranes are made by forming an emulsion of two immiscible phases and then dispersing the emulsion in a third phase (continuous phase). This is a preliminary experiment on removing chloral hydrate from waste water (50-200ppm) with emulsified liquid membrane, i. e. NaOH solution in kerosene. Some conditions which may influence the permeability have been examined. Under proper conditions, more than 95% of chloral hydrate can be eliminated. And the overall transfer coefficient of the membrane has been calculated. The result shows that it tends to a constant.

Study on turbulence field by means of DISA hot wire anemometry is described for: 1. Nozzle: time-averaged velocity, turbulent fluctuation velocity and turbulence intensity are shown to possess similarity when represented on dimen-sionless coordinates, and linear correlations were obtained for maximum turbulent fluctuation velocity and maximum turbulence intensity. 2. Fluidized Bed: time-averaged velocity, turbulent fluctuation velocity and turbulence intensity vary dramatically in distributor plate zone, which therefore defines a region of high mass and heat transfer. 3. Top-Fired Hot Stove: velocity and turbulence fields for a proposed design show a high degree of uniformity, which could be relied upon for prolonged stove life, high thermal efficiency, and energy saving.

A method for the mathematical solution of the flow distribution in a parallel fluid flow system with consumption in branch pipes has been developed. Assume that the flow restriction coefficients and the consumption in any branch pipe are the same, and that the flow is laminar and the variation of hydrodynamic pressure is neglected, then the flow in the branch pipe can be expressed in the following form. (gi+1 - gi)- (gi - gi-1) = 2Rgi - Rgo By transforming it into differential equation d2y/dx2-2Ry =0 where y=gi-1/2 go, x = i we obtain the general solution as follows: gi = C1e where the constants of integration C1, C2 can be directly calculated from the following formulas: C1 = (DB - FG) / (EB - FA) C2=(DB-C1EB)/(FB) where D=R(n-1) for the downstream-system (the system with same direction at its entry and exit). D=R(n-1) (2-k) for the upstream-system (the system with opposite direction at its entry and exit). The results obtained by using the usual method and the new method are the same, while the latter is much more simple and accurate.

This paper presents a constructional idea and operating conditions for a new type of gas-liquid reactor, the shelltube type of bubble-falling film tower. The tower is an improved design of both falling film tower and bubble column, in which two types of fluid distributors for tubes are installed; one is a liquid distributor at top of each tube like in the falling tower, the another is a gas distributor at bottom of each tube like in the bubble column. A combined operation of both falling film in upper half of the tube and gas bubbling in lower half of the tube has been realized through the using of two distributors as mentioned. The paper describes the experimental results of the hydrodynamics for tower in a single tube(φ16-φ36)and tubes(column φ200) in water-air system at atmospheric pressure. It is pointed out that the tower is characterized by the favorable operating performances: large gas-liquid treatment capacity, spacious operation flexbility, stable fluid conditions for gas-liquid stream, lower backmixing of liquid; therefore, it has the features of both bubble column and falling film tower. The essential data for designing have been presented by the experiments.

In the hydrodynamics experiments of a falling-film column, the change of the thickness of fluid film in the falling-film tube with time has been measured, using the Tyndall effect produced by a Laser beam passing through the fluid film. The principle of the test instrument and its construction are described and the results of calibration are presented.