The sublimation and condensation phenomena caused by vapor movement in the pores partially filled with ice during microwave freeze drying of unsaturated porous media is studied. By the use of a sublimation-condensation model developed by the authors in a previous paper,the numerical simulation of heat and mass transfer process for frozen beef under microwave heating is made. The results show that the saturation of ice in sublimation-condensation region would decrease greatly during the microwave freeze drying.The calculation also indicates that the influence of sublimation-condensation region is significant and should not be neglected in microwave freeze drying process as compared with the numerical results of a sublimation interface model under the same operation condition.

In this paper,the adsorption isotherms of surfactants on liquid--solid interface have been classified systematically,and a nonuniform surface two step adsorption model has been developed by the authors.By using the adsorption isotherm equations derived from this model,the correlation of experimental isotherms of L-shape,S-shape,LS-shape,and special shape with maximum and minimum are realized.The agreement between calculated results and experimental data is good.

Circulation and shear in stirring and mixing are quantitatively defined.Stirring power can be resolved as P = QZSk. Circulation rate and total shear intensity,and space distribution of energy dissipation rate should be matched.It is shown by experiments about the influence of mixing on coupling reaction that the impeller with of a medium circulation to shear ratio well matches the requirement of coupling reaction and its segregation index is minimum.The process is simulated by the modified Lagrange method.It is shown that the circulation experience of an aggregate influences the local segregation index,and the segregation index of coupling reaction can be reduced by enlarging the power dissipation per volume,the circulation to shear ratio,and the ratio of energy dissipation in the circulation zone and impeller zone.

In light of the possibility of coulping separation and purification steps with catalytical reaction,experimental and theoretical exploration on the mass transfer process of enzyme membrane reaction-extractor (EMRE) was carried out using enzymatical separation of positional isomers a-and β-naphthyl sulfates as study object.Performance of the concentration and the recovery of each isomer.The corresponding mathematical model was established.Good agreement was obtained between model predications and experimental results under a variety of conditions.

The relations of temperature and water fraction versus drying time during freeze drying of mushroom have been studied.The mathematical model of freeze drying of sublimation-adsorption-desorption was developed based on the energy and mass conservation in dried and frozen regions of mushroom respectively.Experimental values fit well with calculated results.

This paper suggests a late lumping method for a nonlinear state estimation algorithm for wall-cooled fixed bed reactors.The estimator in PDEs is discretized using orthogonal collocation to a set of ODEs and then integrated by the Gear method.The nonlinear algebraic estimation equations for concentration are solved by the Hybrid method.For an industrial process,in considering of the longer sampling interval and time delay of concentration measurement,the estimation of concentration is corrected by a predictive method.The performance of the state estimator is examined by both experimentation and simulation.It is observed that the convergence of the algorithm and the robustness of the estimator are satisfactory.

An adsorption dynamic model for fixed-bed adsorber is developed and solved by using orthogonal collocation method.The adsorption of phenol on activated carbon was carried out by steady and nonsteady method.The diffusion coefficients were obtained by regression of the experimental data of effluent curves and then were used to predict the breakthrough curve under other operation conditions.The results show that the experimental curves agree well with predicted ones.

Simulated annealing,combined with heuristics,is applied to the optimized design of multiproduct bath chemical processes.Global optimum is guaranteed by the use of simulated annealing,local search is speeded up by heuristics. The optimal number,size and locations of intermediate storages are determined automatically.The algorithm has the advantages of lower demand for initial values of decision variables;lower storage;less CPU time for computations and relative deviation of less than 0.5% in comparison with the results of mathematical programming.

A generalized mathematical model was developed to simulate the process of simultaneous biochemical reaction and chromatographic separation.The hydrolysis of sucrose to glucose and fructose was chosen as a model reaction to study the coupling process in a 150cm×1cm glass column.It was found that not only sucrose is completely hydrolyzed,but the glucose-rich and fructose-rich products are also separated.Compared to the concentration overload,the volume overload leads to a higher substrate conversion,while there is little difference for the resolution of products.A good agreement between the theoretical and experimental results is reached at the lower sucrose concentrations.

The expression of process kinetics of protein adsorption in a hollow fiber affinity membrane has been established through analysis of the flow distribution and adsorption reaction.The process of human Y-immunoglobulin adsorption onto an immobilized protein A hollow fiber membrane was taken as an example.Homogeneous binding of uniform sites with the same reaction constant and heterogeneous binding of two different sites with different reaction constants have been considered.Breakthrough curves are obtained through numerical solution of the partial differential equations by finite difference method.The comparison between the predicted curves and the experimental curves showed a better agreement for the heterogeneous binding model.

Based on interaction principle between γ-ray and materials,the authors propose a way to measure cis0-l, 4-polybutadiene conversion rate. γ-ray on-line measurement device is given to measure cis-l, 4-polybutadiene conversion rate.

Viscosities and densities of aqueous solutions of sodium chloride and potassium chloride and their mixtures at different mole fractions were measured at 298.15K from very dilute to saturated or supersaturated concentrations.The newly extended Jones-Dole type equation,being based on existing extended Jones-Dole equation,could satisfactorily represent the experimental viscosities of the systems studied to very high concentrations.With increasing concentration,higher exponential terms of concentration are necessarily added.The values of simple additivity of viscosity for mixed electrolyte solution have been calculated.They are very near to the corresponding experimental viscosities under some moderate concentration. This has been explained that enough water could be used to hydrate the ions,and so the interactions between ions have negligible influence on the viscosities.With the increasing concentration,the calculated values become increasingly lower than the experimental viscosities.It may be assumed that the interactions between ions become stronger and stronger and the real concentration for either of the electrolytes should be higher in the mixture due to each others presence.

The dehydrogenation of cyclohexane was studied in a packed bed membrane reactor (MR) with massfraction 0.5% Pt/A1_20_3 catalyst granules,and also in a traditional packed bed reactor for comparision.Equilibrium shifting was obtained at different reaction conditions such as temperature,reactant concentration,inlet gas flow rate and sweep gas flow rate.The conversion increased with sweep gas rate,but a high inlet gas rate resulted in low conversion in the MR.UP to 3.1 equilibrium conversion,which is 20.6%,was obtained in the MR at 200℃.

A polymerized liposome (PLS) was prepared using a synthesized phospholipid with a diacetylene moiety.The precipitable property of the PLS on salt additions,ligand immobilization,affinity adsorption kinetics and adsorption isotherms were studied.Trypsin was purified by affinity precipitation from a crude pancreatic extract.The specific activity reached about 13000 U.mg~(－1). These results indicate that the PLS is a potential ligand carrier for affinity precipitation of proteins.

The local gas phase flow characteristics of the gas-liquid two phase selfaspirated reversed flow jet loop reactor such as the radial profiles of gas holdup,bubble mean velocity and bubble size,using a miniature dual-sensor resistivity probe,were studied experimentally.A new digital processing method,based on threshold combinations of level and slope,was proposed for phase identification by the resistivity probe.In particular,the effects of the liquid jet flowrates on the local gas phase flow parameter profiles in the jet region and the tubular flow region inside the draft tube were discussed.

Screen printing precision is influenced by the rheology of inks.The effect of surfactants on the rheology of organic vehicles in thick film ink was investigated.The organic vehicles displayed pseudoplastic and thixotropic properties,and the shear-thinning effect for surfactants-containing vehicles can be expressed by the Sisko model.By using surfactants,the precision of printing pattern was improved and the printing line width and pitch reached 100 μm.

The paper presents a preliminary analysis of the kinetics of bacterial pretreatment of arsenical gold ore concentrate from Banbishan,Hebei.The batchwise bioprocessing of the concentrates was carried out in a 10L gas-lift loop reactor with 1 kg load using a mixed strain of Thiobacillus ferrooxidans and Thiobacillus thiooxidans.The level of dearsenication reached above 80% in 5 days of leaching.Comparison of the modelling with experimental data on dearsenication indicates that the bacterial growth can be described by the Monod equation,and modification is also necessary to reflect the inhibition due to the accumulated arsenic in the leaching solution.The leaching of arsenic and iron may be approached with the shrinking-core model,and the dearsenication rate seems to be limited by intraparticle diffusion of Fe~(3+) iron when the mechanism of indirect oxidation of arsenopyrite during bacterial pretreatment is assumed.

The back-propagation algorithm used in artificial neural networks was usled to predict the boiling points of the fluorine-chlorine-substituted ethane derivatives.Using two inertia terms for adjustment of weights and automatic learning step control,the network used a short time for learning.The program was written in FORTRAN.The compiler is NDP FORTRAN.

Gross error detection has great importance and is the necessary step in process data reconciliation.Many methods have been published to solve this problem,but no one can guarantee consistently finding all of gross errors.A combinatory method based upon measurement test (MT) and nodal test (NT) is developed for practical use. The MT-NT combinatory approach makes use of both MT and NT tests and avoids any artificial manipulation.It also eliminates the huge combinatorial problem that is created in the combinatory method based upon nodal test or in the serial elimination method in the case of more than one gross errors in a large process system.

Two new processes for the production of insoluble sulfur (IS) were studied in thispaper.One is low temperature polymerization process of sulfur at temperature less than 350℃ and under atmospheric pressure in the presence of catalyst promotor system,aiming at producing medium grade IS.Another is mixed solvent extraction process with a small amount of additive for the production of higher grade IS.In comparison with the old high temperature polymerization and single solvent (carbon disulfide) extraction processes respectively,these two new processes are lower in first cost and operation/maintainance cost,less energy consumption and safe in operation.