This paper reports the influence of wetting phenomenon (capillary phenomenon) on the relationship of conversion versus time. The solid particle samples used were four kinds of porous particles with different pore structures. Three different wetting conditions on the results of reaction were defined and studied. The first one is the filling of distilled water into evacuated particles to simulate the ordinary initial conditions of gas-solid reactions. The second one is the filling of the solution used for liquid-solid reaction into evacuated particles. The third case is putting the particles directly into the bulk reaction solution as a general practice of liquid-solid experiments. The experimental results indicated the influence of these three different wetting conditions on the conversion-time relationship and a semi-quantitative analysis was made to describe the conversion under different wetting conditions. Considering the first and the second wetting conditions mentioned above as an initial condition for the unsteady state mass balance equation in a single cylindrical pore, the analytical solutions to the differential equations were obtained. The models obtained can be used not only to fit the present experimental results satisfactorily but also to fit the data taken by previous workers with reaction between slag particles and liquid similar to the system studied in the present work.

Martin-Hou equation of state (1955) can be derived on the basis of the multi square-well nonspherical potential hard partical perturbation theory. With turther approximation van der Waals equation of state and Joffle equation of state modified by Barner and Adler can also be derived. Van der Waals equation is the simplest expansion of the perturbation theory. It is truncated to retain only the first-order perturbation term, the first power of the density expansion and the first term of the series expression of the hard particle reference fluid. Joffle-Barner-Adler equation retains higher-order perturbation terms, but unfortunately, it only has one term for the hard particle reierence fluid expression as in the case of van der Waals equation. Therefore the contributions of the repulsive forces can not be accurately represented. The theoretical basis of Martin-Hou equation is comparatively more adequate. It retains the higher-order perturbation terms and the higher-power terms of the hard particle reference fluid expression.

Two novel strategies and their optimized operating modes of batch distillation, i. e. top accumulation under total reflux and varying pressure under combined reflux, are proposed. For the first strategy, the product component is concentrated and collected in a large reflux drum under the condition of total reflux. For the second strategy, the column pressure is varied during operation in order to keep the column temperature below the thermal decomposition point of the residue in reboiler, and a combined reflux is used. The corresponding mathematical models which take into account the holdups in both condenser and column are proposed and solved by using (?) convergency method. The application of these new strategies to the separation of a binary mixture ethanol-isopropanol and a multicomponent mixture n-heptane-n-octane-n-nonane-n-decane show that the present proposals can shorten the operating period by more than 30% and 50% respectively in comparison with the conventional constant reflux operation.

This paper follows preceding paper (I). A new structure of batch distillation column with zero reboiler holdup is described, which is suitable for the case of drawing out heavy component from the bottom. A microcomputer control system with four closed loops for three batch distillation columns is reported. The experimental results of batch separation of a four components mixture with new operating model agreed well with theoretical prediction and showed reliable control by microcomputer.

In a laboratory-scale gas-lift loop reactor with annular bubbling, some hydrodynamic properties, such as gas hold-up in riser and liquid circulation were investigated. The drift flux model was used to study gas hold-up in riser. The relationship among εa, ug and u1 was established as follows: where um =ug +u1, Co = 1.58, vb = 30. 1cm/s. Based on the principle of minimum energy dissipation, the equation of liquid circulation was derived, that is, where K{= [2HgDe/(3λLe]0.5} is a structure parameter, which can be figured out by fitting the experimental data with the equation. According to this equation, the mechanism of circulation can be revealed. Furthermore, because of its general feature, the equation can be used for the description of liquid circulation in any gas-lift loop reactor.

In this paper a new method for the prediction of salt effects on VLE is proposed. The model of Pitzer(1980)is extended to the aqueous multicompo-nent electrolyte systems and mixed solvent/salt systems. After reasonable simplification, the activity coefficient expressions containing only one parameter for each binary electrolyte-solvent action are derived for the solvent and volatile solute. It is possible to predict the VLE of salt-containing systems by using these parameters which can be correlated with binary solution properties. The solvent activities of binary electrolyte solutions including 40 aqueous systems and 7 methanol solution systems are correlated to get the single-parameter of the simplified Pitzers model. Application of this model to the estimation of the vapor pressure depression in 320-403 K of LiCl, NaCl, KAc, HCl, CaCl2, MgCl2 binary aqueous solutions and LiCl, CaCl2 binary methanol solutions has shown good accuracy. The total mean of absolute deviation of 182 data points is 0.65 kPa. By the extended model and parameters correlated at 298.15K, the VLE of five different type of ternary salt-containing systems, H2O +CaCl2 +MgCl2, H2O+KCl + HCl, H2O+CaCl2 + HCl, H2O+ LiCl + CH3OH, H2O + CaCl2 + CH3OH, are predicted with the total mean of absolute deviation of 0.015 in vapor phase mole fraction, of 1 K in boiling point, of 1.92 kPa in vapor pressure.

In this paper the physical meaning of the single parameter in simplified Pitzer(1980) model is discussed. The parameter is found proportional to the hydration number of the electrolyte, therefore the correlation equation is obtained from which this parameter can be evaluated from ionic radii. The temperature dependence of the parameter is also verified by predicting the excess enthalpy of the electrolyte aqueous solutions at 373.15K.

Based on the element balances and bioreactor material conservation of a biochemical reaction, adaptive estimation theory was employed to eliminate white noises during the estimation of cell concentration in spiramycin fermentation processes. The scheme precluded the estimation problems introduced by the complexity and uncertainty of cell growth models. In addition, the relation between the total nucleic acid concentration and the cell concentration was investigated. During spiramycin fermentation, which lasted 100 hours, the estimation values of cell concentration agreed quite well with the experimental results.

Numerical analysis and experimental measurement have been presented for treezing process of foodstuffs in one-dimensional polar coordinates. An assumption of linear temperature distribution was made in the transient regime, resulting in improvement of the traditional enthalpy method. This method was applied to the freezing of cylindrially shaped foodstuffs. The control volume method was used in the discretization of the control equation to establish a mathematic model of this process. Its results are more reasonable than the traditional enthalpy method and in good agreement with the experimental data.

A new complex reaction network has been proposed for the hydroisome-rization of C8-aromatics, in which three xylene isomers, ethylbenzene and a lumped component C8-cycloparaffins are present in the reaction system with the products from all irreversible reactions lumped into one pseudo component. The kinetic model of Hougen-Watson hyperbolic type is used to describe the complex reaction network. Experiments were conducted in a flow-type mini-reactor with on-line GC analyzer. The catalyst used is ot Pt/Zeolite type (SKI-300). Measurements were made at an approximately constant activity and selectivity level of the catalyst A trial and error matrix method was used to solve the hyperbolic kinetic problem. The parameters of the model and the activation energies and trequency tactors were obtained from the experimental data.

The separation of water-ethanol mixture by vapor phase adsorption on 4A molecular sieves was investigated theoretically and experimentally. An improved mixing pool model was proposed with consideration of axial mixing, varying gas velocity and mass transfer resistance. The numerical solution of proposed model was also presented. The predicted breakthrough curves agreed well with the experimental results.

The one-mode mean-configuration model proposed by Giesekus has been generalized to non-isothermal cases. The well-known viscosity-temperature equations can then be used to account for the effect oi temperature and thermal history on the stress tensor and obtain a constitutive equation that describes the non-isothermal rheological behavior of concentrated polymer solutions and polymer melts without the necessity of introducing any assumption of non-isothermal behavior into molecular models. The calculations of non-isothermal stress growing indicates that the constitutive equation gives a reasonable description of the non-isothermal rheological behavior of polymer liquids without the disadvantages involved in the constitutive equations proposed by the previous investigators.

The liquid hold up and axial dispersion in a trickle bed reactor were studied in this investigation. In the range of liquid superficial velocity 6.15× 10-3-2.37×10-2m/s and gas superficial velocity 7.07×10-3-0.56m/s, pressure drop and liquid hold up were obtained simultaneously using four gas-liquid systems and six kinds of packing at 298±1K. In the experimental range used, the dynamic holdup data could be correlated by: The results showed that the liquid hold up in trickle beds with three-lobe particles was higher than that with cylindrical particles ot equivalent sizes. Curves of liquid phase residence time distribution under trickle flow conditions were plotted and interpreted in terms of dispersion model. The results were correlated by:

Based on a model treating the interfacial region as a single phase of some thickness, an equation with two adjustable parameters was developed to relate interfacial tension with solubility for two-liquid-phase ternary mixtures. The equation was tested for 24 ternary systems with satisfactory results. With the interfacial tension and mutual solubility data available for the partially miscible pair of a ternary mixture, a modified equation was proposed for even better correlation.

There exist hundreds of soda lakes in Inner Mongolia Autonomous Region and other provinces of China, with their main constituents Na2CO3, NaHCO3, NaCl and Na2SO4. If the brine is processed by simple carbonization to precipitate NaHCO3 as an intermediate product and the mother liquor is discarded, the utilization of sodium will be rather low. An ammoniation-carbonation process was proposed[5], in which a large proportion of NaCl and Na2SO4 will be converted to NaHCO3 also. In addition, NH4Cl and the unreacted Na2SO4 may be separated as final products from the NaHCO3 mother liquor. For the purpose of optimizing operation, the phase diagram of Na+, NH4+//HCO3-, Cl-, SO42-, H2O system at 35℃ was studied and some operating problems were discussed. The phase diagram showed that in order to raise the NaHCO3 yield, the[2NH3]/([Cl22-]+[SO42-])ratio in the ammoniated brine must be increased. Take the Dabusu Soda Lake brine as example, if the[2NH3]/([Cl22-] +[SO42-]) ratio is raised to 0.738, the sodium utilization UNa would be increased to 78.9%. But this is the limit value for [2NH3]/([Cl22-]+[SO42-]) ratio. If it is exceeded, NH4HCO3 would be precipitated together with NaHCO3.

A new approach to determining bubble point or dew point of a binary mixture has been proposed. From an equilibrium still operating steadily at a constant pressure, a portion of the equilibrium binary solution (its composition x1(0) to be evaluated) is replaced by an equal amount of solution having a known composition x1(1). If the equilibrium temperature before and after the replacement remains unchanged, i. e. T(0) - T(1)=0, then x(0)=x1(1) and the bubble point[T(1), x1(1)] is thus obtained. On the contrary, an inequality of T(0) and T(1) indicates x1(0)≠x1(1). In the latter case, pure component 1 or 2 is added in successive small increments to adjust the temperature in the still to the neighborhood of T(0), and then the replacement is repeated by a new solution of composition x1(2). The foregoing procedure is repeated until | T(n-1)-T(n)| or | x1(n-1)-x1(n)| comes up to the desired precision and the final point[T(n), x1(n)] is the bubble point of the system. In a similar way, the dew point could be obtained by replacement of the equilibuium vapor in the still.

A numerical control scanning Gamma ray attenuation technique is developed and applied to the study of two phase fluid characteristics on distillation trays. It is sensitive, reliable and quick in measurement. Dispersion densities, integrated clear liquid height, froth height, horizontal dispersion density profiles, perpendicular dispersion density profiles, liquid height gradients, crest over the weir and so on can be measured. Integrated clear liquid height and froth height in the downcomer may also be examined. A "pulse spray" mechanism is proposed to explain the flexion observed pn the density profile of disperson.

The properties of oscillatary states caused by Bang-Bang control of non-isothermal and non-adiabatic fixed bed reactor have been studied experimentally. In o-xylene catalytic oxidation the phthalic anhydride yield with Bang-Bang control may be higher than that in the steady state operation by about 3% (mol/mol). The causes of higher yield of phthalic anhydride with dynamic operation were also discussed. Compared with the classical setting value control method, Bang-Bang control may provide another measure tor engineering control and provide greater operating flexibility.