An experimental set up which can be used to measure the potential distribution in a packed bed electrochemical reactor by an automatic data collection system was installed. Experiments were carried out to check with the model presented in the literature[2,3] of the study. The experimental data are in good agreement with the model calculations. The mentioned model is verified to be a general one which can be used for different operating regimes. The factors effecting on the potential distribution in the packed bed is also discussed.

The process,electrochemical reduction of nitrobenzene to produce p-amino-phenol in a packed bed electrochemical reactor, is investigated. The reactor is desiged with the aid of the reactor model established in the literature [7,8] of the study. Applying this model, the authors calculate the model of the reduction of nitrobenzene for p-aminophenol process and compare with the experiments. The experimental results show that this process can be operated at acurrent density i≥2000A/m2, selectivity β≥80.0%, and current effenct ηi75.0%. This study provides a very important basis for the industrialization of the studied process.

A new method of measuring the flow capacity of cell gas in the chlorate cell process equipped with an oxygen cathode is applied to investigate the influence of changes in the concentrations of solutions (chloride, chlorate, hypochlorite and addition of foreign salts) and changes in the operation parameters (current density, temperature, pH and flowvelocity) as well as changes in the anode materials on chlorate current efficiency. The concentrations of salts (chloride and chlorate), current efficiency and energy consumption as a function of time are given in a batch process with sodium chloride from 310 g/L to 30 g/L.

Landolt and Ibls hypothesis on the model of anode diffusion layer is analyzed and two main ways of oxidation with respect to hypochlorite diffusing to the anode surface are considered. According to the analysis Jaksics mathematical model of current efficiency related to the anode diffusion layer is modified with an electrolytically characteristic parameter. The running fluid near the surface of gas-evolving electrode at a lower velocity is suggested to be in a turbulent pattern. A relationship between flow velocity, current density and thickness of diffusion layer is deduced. The influence of velocity and current density on current efficiency in the chlorate cell process is established by combining with the modified Jaksics model. The phenomenon of current efficiency with the increase of chlorate concentration is investigated with respect to activity, viscosity and chemical bond.

A three-dimensional mathematical model has been developed for predicting the transport of mass, energy and momentum in the combustion chamber of a rectangular multi-burner. The turbulence two-equation model and Monte-Carlo method ard used for simulating the turbulence flow and radiative heat transfer, and a combustion model of turbulent diffusion flame is considered. The governing differential equations which are composed of velocity, mixture fraction, fuel concentration, stagnant enthalpy, turbulent kinetic energy and turbulent energy dissipation are solved by tri-diagonal matrix algorithm. The distributions of the temperature of fuel gas and the heat flux of wall are predicted in a coking furnace. A comparison between the calculated and measured results shows that the prediction is successful.

In this paper non-homogeneous characteristics and special fluctuation structures of gas-solid slugging fluidized bed is analysed. Based on analysis of fluctuation mechanism,a method of discrete analysis of fluctustion dynamics is proposed and a random model of multivariant vibration is set up for slugging bed. By combining spectual and statistic analysis, the model solution is obtained in the form of matrix equation GΔjΔk (ω) = H * (ω)Gδjδk(ω)HT(ω) It can be used to express the vibration structure and the power spectrum of pressure fluctuations in slugging bed.

In this paper the parameters of the random model of multivariant vibration for, slugging bed are investigated. A trial-and-error method is proposed to determine the length of gas slugs and particle slugs in the bed. A white noise disturbing function is designated for bottom disturbing forces of the bed, and a normal disturbing function for surface disturbing forces. Model simulations demonstrate a good coincidence with experimental results in expressing dynamic characteristics of vibration structures, frequency spectrum of pressure fluctuations and propagation and attenuation of fluctuations in the bed.

For certain types of chemical reactor whose catalyst decays rapidly but reversibly, continuous operation is possible by the use of a moving bed radial flow reactor. There is an upper limit on the flowrate of gas imposed by the mechanical phenomenon of "pinning" and the formation of cavity. The dimensionless pressure drop for cavity initiation can be predicted by using the theories of particulate media mechanics, with the gas stream flowing outward radially. The theoretical results agree very well with the experimental data.

The mixed integer nonlinear programming(MINLP) model by Modi et al. was modified for optimized design of multiproduct batch chemical processes to accomodate not only the existence of intermediate storages but also the adjustment of the number for parallel units operating in-or out-of-phase. A heuristic algorithm for solving the model mentioned above was proposed the advantages of which were lower demand for initial values of decision variables; lower storage and less CPU time for computations and relative deviation of less than 1 % in comparison with the results of using mathematical programming software (MINOS 5.0). An example was shown to prove its availabilities.

In an earlier study, we proposed a new method in which the surface tensionsof mixtures of organic non-electrolytes are predicted successfully by the well-kn own UNIFAC group contribution method used in phase equilibrium calculations. In this paper, four different molar surface area equations are investigated with respect to precision of surface tension prediction by the use of our proposed method of applying UNIFAC model. Different molar surface area equations are given as: Ai=Ai = ViB2/3NA1/3 (1) Ai=Ai = 1.21ViB2/3NA1/3 (2) Ai=Ai = ViB4/15Vic2/5NA1/3 (3) Ai=Ai = 1.21ViB4/15Vic2/5NA1/3 (4) where Ai and Ai are the molar surface area and the partial molar surface area of component i respectively, ViB is the liquid molar volume of pure component i, NA is Avogadros number, and Vic is the critical molar volume of component i. The surface tensions of 100 binary, 10 ternary and 2 quaternary systems are calculated with the above equations. Comparing calculated values vith experimental data, we conclude that equation(4) is the best for the systems containing both water and alcohols. The total average relative deviations from experiment are 6.98% for 6 systems containing both water and alcohols. These results are satisfactory for engineering design.

The effects of various nutrients in fermentation broth on the volumetric liquid-phase mass transfer cofficient kLa were studied in a bubble column. The mathematical model for measuring kLa was modified. The correlation of kLa was derived theoretically as follows It was shown that the presence of macromolecular carbon source or nitrogen source decreased kLa, while that of urea and inorganic salts with low ion strength ( < 0.02kmol / m3) had no effect on kLa and the presence of glucose and inorganic salts with higher ion strength ( ≥0.02 kmol/m3) could increase kLa. Parameters of the correlation were determined according to the different effects of various nutrients. Values of kLa from the correlation agree well with the measured values.

A mathematical diffusion model discribing the profiles of concentration and temperature in industrial catalyst particles is given. An effective algorithm based on false transient method to solve the non-isothermal diffusion model is developed. In this paper the numerical solution of the temperature profile and the concentration profile of each reaction component and the numerical solution of effectiveness factor of high-temperature shift reaction catalyst B109 are obtained from 16 groups of experimental data of global rates. The radius of "dead zone" and the effectiveness factor can be directly determined by applying this false transient method and without the need for changing of boundary conditions. The calculated results are reasonable and the calculation is not time consuming.

The mechanism of purification by continuous multistage countercurrent fractional crystallization has been studied. For a low eutectic system, countercurrent washing plays a main role in purification. The mathematical model which describes the impurity concentration vs. the crystal bed height in the purification column is as follows The influences of operating variables such as feed composition, reflux ratio, height of crystal bed and agitation intensity were studied theoretically and experimentally as well. A purification column 50 mm in diameter and 1060 mm in height was used in the experiments.The experimental results indicate that all the variables have important influence on column performance and the mathematical model gives results in good agreement with the experimental results.

The foam rheological properties are studied experimentally in this paper. Foam behaves like a pseudoplastic fluid with a viscosity inversely proportional to shear rate. Its apparent viscosity is affected strongly by foam quality. From experimental results, the rheological parameters, K and n, are determined and two correlations are obtained: Additionally, the rheological properties of foam are related with the type and concentration of foaming agents, diameter of foam, temperature, etc.

The concept of separated flow and numerical calculation of two-dimensional unsteady heat transfer were used to develop a model of the temperature change of flue gas flowing out of finned tube bundles. A method for comparison was designed to improve the separated flow model and the transient experiment method. The heat transfer coefficient of air flowing transversly through crossed finned tube bundles was established in this way and experimental study on the coefficient was made with the constant wall temperature method. The result was satisfactory.

In this paper, an equation for the local blood-side Sherwood number is derived from the advancing front theory (AFT) for mass transfer of oxygen in a parallel plate membrane oxygenator. The maximum deviation of the approximate solution in comparison to the classical Graetz-Leveque solution is reduced to 6.58% from 22.3% by srinivasan et al. The simple analytical expressions enable analysis of the effect of oxygen reaction and membrane resistance on mass transfer. The design criteria for the channel length of a parallel plate membrane oxygenator are proposed.

In terms of the hard sphere, a model equation has been developed to correlate mutual diffusion coefficients with concentrations. By appling to 36 binary systems, the equation proposed has higher accuracy and applicability, and it can be used to predict the diffusion coefficients at different temperature from the data at one given temperature. At the same time, the liquid diffusion coefficient at infinite dilution over an extended temperature and pressure range can be accurately correlated and calculated with the equation deduced from the model.

Benzene alkylation process is a typical catalytic reaction. When the reaction is carried out in gas phase or liquid phase, obvious catalyst deactivation is observed. This paper aims at slowing down catalyst deactivation of benzene alkylation reaction by taking advantage of some special properties of supercritical fluids (higher solubility than gases and higher diffusibility than liquids). The results indicate that when the reaction condition is above the critical point of the mixed reactants, the coke precursors (polynuclear aromatics) which directly deactivate catalyst can be removed by dissolution in the supercritical fluids, which leads to a longer catalyst life.