The Calculation of the residence time distribution (RTD) and the mean extent of reaction of solid particles in a fluid-solid particles reactor systems with back-flow between stages is rather complicated. They are nonlinear and stochastic in behavior. In this paper, Monte Carlo method and procedure have been adopted to simulate the stochastic problem. A large number of discrete particle examples have been simulated and followed. Pseudo-random numbers picked from a range of uniformly distribution(0,1)have been used to simulate random residence time, stochastic back-flow phenomenon and reaction of particles. The last information on statistic results of all particle examples is the solution to the problem under steady flow state. The results are in good agreement with those obtained from other known methods for determining RTD and particles reaction of first order in systems with back-flow. For non-first order reaction systems, the extent of reaction of solid particle is rather different from that of homogeneous phase reaction, which arises from nonlinear in nature and after-effect (or no-Markovian) property in particles reaction systems. The method can be considered as being simple in physical concept and readily applicable in computer procedure, and can be applied to a variety of fluid-particles reactor systems.

A stochastic approach, namely, Monte Carlo approach, and "tree" structure have been adopted to simulate random backmixing, unreacted fraction of solid particles including multi-size particles, and dynamics of particles with complex reaction in a complex flow system. Turbulence of particles in the reactor system is simulated by stochastic tree pattern which is shown by pseudorandom number series picked from a uniformly distributed set of numbers between zero and one. A Monte Carlo procedure is employed to model particles stochastic residence time, random flow and reaction. A large number of discrete bundles of particles have been simulated and trailed. The approach has simple physical concept and imitative procedure. All calculations have been carried out easily with a computer. For a simple reaction system, the results are in good agreement with those obtained from other known approaches. The approach could provide a new kind of technique for simulating behaviors of particles in continaous flow reactor.

The intrinsic kinetics of the methanol synthesis from carbon monoxide, carbon dioxide and hydrogen over C301 commercial catalyst are studied. The investigation is performed under typical commercial conditions. The two independent reactions chosen in this work are the synthesis of methanol from both carbon monoxide and carbon dioxide in the reacting system. Reliable kinetic models which adequately describe the results are derived from the two reactions.

The global kinetics of methanol synthesis from carbon monoxide, carbon dioxide and hydrogen under typical commercial conditions over C301 commercial Cu-based catalyst are studied in a CSTR. The two independent reactions in this work are chosen as follows: CO2 + 3H2 CH3OH + H2O Global kinetics model which conveniently describes the results is derived from the two reactions. The influence of reaction conditions on the effectiveness factor of methanol synthesis is also discussed.

For multiple reaction systems of methanol synthesis in the presence of Cu-based catalyst, CO and CO2 hydrogenations are selected as key reactions. In this paper, a diffusion model for the key components CO and CO2 is presented for calculating the effectiveness factors of C301 Cu-based catalyst pellet in two parallel reactions; numerical solutions of the effectiveness factors ξco and ξco2 are obtained. Reaction characteristics of the catalyst pellet is discussed. Experimental values of ξco2 and ξco are obtained at 5MPa pressure in an internal recycle gradientless reactor in which the macro-reaction rates take into account only the intraparticle diffusion on φ5 × 5mm cylindrical pellet of C301 Cu-based catalysts. The average absolute deviations between model calculated values and experimental values for ξco and ξco2 are 9.9% and 23.9%, respectively. Compa-risions between model calculated values and experimental values of ξco and ξco2 indicated that the model is simple and is feasible for the calculation of the effectiveness factors of parallel reactions.

As a follow-up of previous work done, the two-phase flow characteristics in a pulsed-sieve-plate extraction column are being further studied. The hindering effect of drops, the - coalescence effect of drops, the interrelation between characteristic velocity and terminal velocity of single drop in the column and the flooding velocities are discussed. Semi-empirical equations are suggested. Work done in this respect serves as a basis for the scaling up of pulsed-sieve-plate extraction columns.

The kinetics of the oxidation of methanol to formaldehyde in the presence of Pb0.88 Bi0.06 La0.02 Mo/SiO2 catalyst was described by the Redox mechanism. When the particles of catalyst were increased to 3mm in diameter, the effect of intraparticle diffusion depended greatly on the oxidation rate of methanol to formaldehyde. The effectivenese factor of the catalyst was determined to be 0.28-0.12 and was interpreted with the kinetics of the Redox mechanism. The kinetic equation of the Redox mechanism in the presence of the intraparticle diffusion of methanol molecules was interpreted by the theory of diffusion and was proved experimentally. The apparent activation for the oxidation of methanol in the presence of intraparticle diffusion was determined by kinetic experiments and interpreted by a theoretical equation. The effective coefficients of intraparticle diffusion of methanol and the tortuosity factor of the catalyst were determined by kinetic experiments conducted with reaction conditions investigated.

The effects of flow ratio on the continuous phase separation of a liquid-liquid system, composed of 2-ethylhexyl-phosphoric acid mono-2-ethylhexyl ester-kerosene/rare earth chlorides solution, have been studied in a mixer-settler, having a total volume of 0.01m3 and equipped with double mixers in each stage. Separation is conducted under three different settling environments in the settler i. e. gravity field, enhanced settling baffles and low-voltage electricfield, and with two kinds of dispersion and five flow ratioes of the organic phase to aqueous phase (Qo/Qa) from 3:1 to 1:3. The volume of dispersion band in the settler and the values of entrainment of the two phases are being measured. The results show that: (1) Under the action of gravity field or the enhanced settling baffles, the effects of flow ratio on the phase separation of the two kinds of dispersion may be characterized by the volume of dispersion band in the settler and the values of entrainment of the two phases; (2) Under the action of gravity field, a more ideal but different flow ratio occurs in the phase separation of both kinds of dispersion, i. e. water-in-oil and oil-in-water, corresponding to a lower volume of dispersion band and a lower values of entrainment of the two phases respectively; (3)Under the action of enhanced settling baffles, there exists a more ideal but different flow ratio in the phase separation of the two kinds of dispersion mentioned above, correspoding to the best effects of decreasing the volume of dispersion band and the values of entrainment of the two phases respectively; and(4)Under the action of lowvoltage electric field, the volume of dispersion bands decreases tremenduously at all flow ratioes tested for the phase separation of water-in-oil dispersion, moreover, the more ideal flow ratio corresponding to the best effects of decreasing the volume of dispersion band and the values of aqueous phase entrained tended to be identical. The authors suggest that the effects of phase separation should be fully attened to when a suitable flow ratio is selected and the volume of dispersion band and values of entrainment of the two phases should be thoroughly examined and balanced when the effects of phase separation are considered.

This paper proposes that a critical compressibility factor Zc can be used as a fourth parameter for corresponding states, as a result of the analysis of the relationship between Zc and acentric factor w. Two formulas used in the Patel-Teja equation of state for expressing molecular characteristics can be improved by using Zc. Excellent results are obtained with these two new formulas for predicting certain polar molecules not included in the process of fitting parameters. Bhirud equation, which is only adoptable for saturated liquid volumes of non-polar molecules, has been successfully extended for polar molecules. For polar molecules, no definite relationship does exist between Zc and w. It is assumed, therefore, that Zc would probably serve as a good correction factor for some formulas in which w is used as the third parameter for corresponding states.

The rate of reaction between nitrosyl ferrous ethylenediaminetetramethy-lenephosphonate and sodium sulfite in aqueous solutions was measured spec-trophotometrically at temperatures ranging from 20 to 35℃ and over the pH range 5.57 to 7.48 with the aid of a rapid mixing device. The FeII (EDTMP) (NO) solution, prepared by introducing nitric oxide into FeII (EDTMP)solution, was mixed instantaneously with sodium sulfite solution. Then the sequential change in absorbance of the solution at 590-600 nm was scanned. The reaction was of second order at pH 5.88 and I = 0.3 mol/l.The reaction rate constant k at 20,25,30 and 35℃ was determined to be 1.95,3.03, 5.48 and 7.05 l/(mol. min), respectively. The apparent activation- energy for this reaction was calculated to be 68.6kJ/mol, which was smaller than that of the-FeII(EDTA)(NO)system(102.9 kJ/mol at pH 5.97). The dependence of the reaction rate on pH was discussed.

This paper presents a steady state mathematical model for a catalytic cracking riser. The model is based on practical experiences and their related reaction mechanisms. For a given catalyst and under specific pressure conditions in the riser, conversions, gasoline fractions and temperatures within the riser can be predicted. The model parameters are estimated from experimentally measured date obtained with a catalytic cracking unit. Started with a nonlinear model, a linearized model and a parameter correcting model are hereby proposed.

Basing on the assumption that the average torque exerted on the wall surface in an agitated vessel is approximately equal to that offered by a rotating impeller and introducing the conception of flow regime coefficient. a new shear rate model used to calculate apparent viscosity of non-Newtonian fluids is proposed. The impellers investigated are MIG impellers, flat blade disc turbines, pfaudler impellers, plate paddles, anchors and a semielliptical board impeller, diversing widely in geometrical configurations respectively. Three types of cooling tubes (inner helical coil, external helical coil and vertical tubes) are respectively equipped inside the vessels. Using the present model, heat transfer correlations are respectively obtained for the three cooling tube systems. The correlations can be used in the design and scale up of industrial agitated vessels. The results indicate that this model can be used to correlate heat transfercoefficients of non-Newtonian fluids in various cases such as different cooling tube systems, various types of impeller, unbaffle or with vertical tubes as baffles, transitional regime or turbulent regime and jacket side or cooling tube side. Comparison between the present shear rate model and those developed previously is also presented.

The ultrasonic degradation of polyvinyl alcohol (PVA) in aqueous solution and the copolymerization of PVA with acrylonitrile (AN) were studied. It was confirmed that the rate of degradation of PVA followed the kinetic equation suggested by N. K. Baramboim. Both water-soluble and water-insoluble copoly-mers could be obtained by changing the irradiation time or the amount of AN added to the aqueous solution of PVA. The structure of the copolymer was identified by IR, MS, PGC and X-ray diffraction. The copolymer prepared was mainly a blocked one. By irradiating 2% PVA/AN (1/1.6, by mass) at 20±1℃ and 21.5 kHz with 490W for a period of 28 min., the yield of the water-soluble copolymer was 25.49%, with a AN content of 13.98%. When the irradiating period was extended to 100 min., with the mass ratio between PVA and AN at 1/4, the yield of the water-insoluble copolymer amounted to 296.01%, with a AN content 75.56%.

A shrinking unreacted-core model for catalytic steam gasification of coal was derived through a series of mathematical treatment, and the value ofthe related parametera were determined by experiments. This model served well to describe the charac-teristics of the catalytic steam gasification of Jiao Zuo anthracite, with the varying activities of the catalysts during gasification. In particular, computed results obtained by employing this model agreed fairly well with experimental data.

The current status and development of numerical modeling of two-phase flows of gasparticles or liquidparticles with and without chemical reactions are reviewed. Different approaches for handling the particle phase, e. g. the single-fluid model, the particle trajectory model, and the two-fluid model, as well as their application and assessment are discussed. A number of modifications for the above mentioned models and new models, such as continuum-trajectory model and continuum model accounting for particle history effect were presented. The authors points of views on the subject were also given. Future trends in the area was discussed.

In this work, tne authors modified the structure of presaturators and determined 88 activity coefficients at infinite dilution of 52 binary systems at various temperatures by gas chromatography with double saturators. Data for 14 among these 88 were found to conform pretty well with those disclosed in literature. For systems containing ethylbenzene, the results indicated that good linear relation between In γ1∞ and the reciprocal of temperature was obtained and the heats of solution at infinite dilution of these systems were evaluated.

The influence of viscosity on the axial mixing of liquid phase was studied in the viscosity range of 0.0008 to 0.014 Pa·s, and the following relation Ped = A Fr1B(v1/vw)c was proposed, where (v1/vw) is defined as viscosity correction factor. The index value C is found to be -0.15 for conditions below the loading point and -0.138 for those within the loading range.