When the simulation and optimization of large-scale chemical processes is wede,the computational time is enormous because of the large scale of the system.Along with the rapid progress of computer science and techniques,utilizing parallel computing techniques to improve the efficiency of chemical process simulation and optimization has become a remarkable hot spot.The present paper reviews significant researches reported on parallel computing techniques applied in chemical process simulation and optimization.The researches of parallel computing in chemical process simulation and optimization are mainly aimed at solving a large sparse system of linear equations.The researches reviewed are classified into simulation and optimization of chemical processes.Finally thoughts about future research challenges are offered.

Using five measurement tactics protocoled,the effects of membrane morphology,membrane fouling and concentration polarization on streaming potential were studied.Experimental results show that the compaction of microfiltration membrane can result in some morphological changes,hence in streaming potential variation.But this kind of change of ultrafiltration membrane is not obvious.Among the five measurement tactics used,reducing pressure step by step after compaction at higher pressure is the best.The research work also verified that charged ultrafiltration membrane could partially reject the salt in solution and the presence of concentration polarization and fouling influenced streaming potential.

A model of "mixed phase flow" for preventing and cleaning fouling on inside tube wall by increasing three phase flow shearing stress was presented.The model can be used to study the mechanisms of preventing and cleaning fouling in the three phase circulating fluidized bed evaporator.The individual effects of operational parameters on three-phase flow shearing stress were studied.A saturated bittern solution was chosen as the work material.The fouling period of the saturated bitten could be prolonged effectively by increasing the amount of solid particles.

A surface free energy difference criterion,i.e.the surface free energy difference between condensate liquid at condensation temperature and solid surface, was proposed to predict whether filmwise or dropwise condensation of a vapor occurs on a solid surface.The critical surface free energy difference was considered to be 0.0333J·m ^-2 .The surface free energy of a solid can be calculated from the measured contact angles at room temperature for low surface-free-energy solid surfaces like polymer films.Consequently,it is more convenient and accurate to use the surface free energy rather than the contact angle to predict condensation mode because the surface free energy difference is independent of the temperature for contact angles measurement.It is of considerable significance to get more insights into the mechanism of condensation heat transfer enhancement by means of surface coatings.Meanwhile, the criterion is much helpful to choosing the coating materials that promote dropwise or dropwise-film coexisting condensation modes according to the condensing vapor.

An advanced hydrodynamic model, k-ε-k _p- ε _p- Θ two-phase flow model is established to simulate the gas-solid turbulent flow in riser reactor.The model,based on the kinetic theory of granular flow which recently is widely used to describe particle flow and simulates both gas phase and solid phase by low Reynolds number turbulent model taking into account the turbulent interaction between gas and particles.The model equations is coded and solved by CFX4 package,a CFD software developed by AEA Technology Company.The predicted results show satisfactory agreement with experimental data.Moreover the detailed analysis indicates that it is reasonable to add the particulate turbulent energy equation and its dissipation equation,and the closure method of the interactions between the turbulence of gas and that of particles is a crucial factor that influences the predicted results.

Thermal cracking reactions lead to excessive light gas yield and lower overall product values during the present typical high temperature commercial FCC operation.Catalyst properties and operating parameters (reaction temperature,catalyst to oil ratio,contact time) have great influence on thermal and catalytic cracking reactions.There exist some points of reaction temperature inflexion for catalytic cracking reaction and thermal cracking reaction.Catalytic cracking reaction plays the main role below around 538?℃,and the ratio of (C ₁+C ₂)/ i -C ₄ is less than 0.6.When the reaction temperature is over around 610℃,thermal cracking reaction is the key process and the ratio of (C ₁+C ₂)/ i -C ₄ is large than 1.2.Below the temperature of 550～610℃,catalytic cracking reaction and thermal cracking reaction can occur simultaneously,and the latter becomes dominant one when the reaction temperature increases.The rate of catalytic cracking reaction can increase with increase of the ratio of catalyst to oil resulting in much more amounts of active sites involved.The deposition of product coke on the catalyst leads to more severe thermal cracking reaction by making the active sites inaccessible for future participation in the catalytic cracking cycle.The short contact time of oil and catalyst may suppress the detrimental thermal cracking reaction dramatically.A satisfactory result could be obtained through selection of proper catalyst and operating conditions (especially the very short contact time of gas and oil).

Conditional moment closure(CMC) model proposed by Bilger is used for simulation of CH ₄-Air diffusion combustion and its NO _x formation,taking into account a radiant heat losses in this paper.Simulation is carried out by using k-ε-f-g model for velocity and mixed fractions,and a parabolic equation of conditional moment closure (CMC) for component concentration.A comparison of the prediction and experimental data demonstrates that CMC has good performance in the prediction of the fields of velocity,temperature and main component(CH ₄,CO ₂) concentration,the prediction of NO concentration is in agreement with in experimental data with acceptable departure.

A mathematical model was proposed to describe the heat transfer in nucleate pool boiling.The model addressed the three-dimensional conduction heat transfer process within the problem domain comprised of the heating wall,and the effect of bubbles or sites was represented through boundary conditions.Numerical simulations were performed and a excellent agreement between the available experiment data and numerical simulating results were gained.By numerical simulation,the predicting methods of the bubble influence area factor and the flow strength parameter were obtained.In addition,the nonlinear characteristics of wall temperature variation and bubble wait time were identified.

Investigations were carried out, under uniform wall temperature and constant heat flux boundary conditions,on heat transfer and frictional characteristics of transverse tube with large roughness for laminar and turbulent flow of oil in a condensation test facility.The parameters tested were Re =50-6200, Pr =75-260,roughness height e =5mm,and pitch p =30mm.The experimental results show that the frictional and heat transfer characteristics of test tube differed greatly with those of conventional enhanced tubes,which use water or air as working fluid,due to the interaction of its special geometrical configurations and oil thermal properties.Also,the difference in friction and heat transfer data by using different test methods was found to be extremely small.The correlations of dimensionless friction factors and heat transfer coefficients were proposed on the basis of experimental data.Finally the experimental data were compared with computational results obtained by Ravigururajan and Bergles correlation.

The cultivation of encapsulated S cerevisiate cells in NaCS-PDADMAC polyelectrolyte complexes was studied. The results showed that the encapsulated microorganisms had the same growth trends as in its free cell culture and thus NaCS-PDADMAC microcapsules were suitable for the encapsulation of biological substances. The encapsulated S cerevisiate cells were fermented sequentially in 16 batches. The highest cell density in the capsules reached 2 64×10 ¹⁰ cells·ml ^-1 and the ethanol concentration was 47 0 g·L ^-1 .A model of the cultivation of the encapsulated S cerevisiate was developed.

Several indexes of metabolism were monitored when the Fungal elicitor originated from Fusarirm oxysporum , whose main ingredients were polysaccharide and protein, was added into the cells suspension cultures system of Taxus chinensis var. mairei in the later exponential growth stage of cells. The results showed that the structure of metabolism was modified, the intracellular protein increased first following a decrease in the later stage,while the extracellular protein kept increasing all the time. PAL, an important enzyme of phenylpropanoid pathway, had its activity promoted obviously, and the phenolics accumulation was strengthened and a sharp increase of it could be observed in the later stage of treatment. At the same time, the activity of PPO increased,and the production of taxol was promoted evidently.

The mass transfer in catalyst capsule is analysed.It is pointed out that the wetting incompletion of catalyst beads and the concentration gradient within the catalyst capsule reduce catalyst efficiency.The effectiveness factor of catalyst capsule equals to the product of η _s and η _c.The former,the effective wetting rate of catalyst beads,represents the influences of wetting incompletion of catalyst on catalyst efficiency,the latter represents that of concentration gradient.A two- dimensional model is established and an equation to calculate η _c is given.It is indicated that η _c is influenced not only by radial diffusion,but also by axial liquid flow.The influence of diffusion resistance on effectiveness factor is greatly weakened by axial liquid flow.

A recycling batch reactor is designed to measure the kinetics rate,in which the catalytic capsules are installed in the same way as in catalytic distillation column and the liquid flow condition is similar to that in catalytic distillation column.The apparent kinetics of the hydrolysis of methyl acetate is studied and the effectiveness factors are tested for different capsule size under different conditions.The effective diffusivity within the catalyst capsule is calculated to be about 9×10 ^-8 m ²·s ^-1 .The mass transfer model reported in part one of this paper is used to calculate the effectiveness factor of catalyst capsule.It shows good agreement between the predicted values and experimental data of effectiveness factor.Maximum deviation is 13 7% and average deviation is 3 2%.

Initiated by bi-benzoyl peroxide (BPO), maleic anhydride (MAH) was grafted onto the surfaces of polypropylene (PP) beads, swelled with a small amount of toluene, at the boiling point of a self-stirring water suspension system. The influences of reaction time and the dosage of MAH and BPO on graft degree of the copolymer were investigated by orthogonal experiments. Under the chosen optimal condition of 120ml water, 10 ml toluene, 0 3g BPO, 8 0g MAH and 20 0g PP reacted through circumfluence for 4 5h at the boiling point 102℃, MAH grafted PP (MAH- g-PP ) with a graft degree 9 06% was obtained and it’s graft status was characterized by FTIR spectra. The results from a series of adsorption experiments demonstrated that MAH- g-PP showed much more affinities to polar substances like water, Cu ²⁺ , dyestuff and glucoamylase in comparison with the affinities of PP, and revealed the promise future of its wide application in solubilizers for PP alloys, ionic exchange resins, antibacterial materials, medicine carriers and enzyme supports etc. The titled method has outstanding advantages in process controls and post treatment.

Mass transfer coefficient is an important parameter in the calculation and design of mass transfer processes. Many variables affect the value of mass transfer coefficient. Among which, the effect of concentration has not yet been paid due attention. In an experimental column containing 6 trays, two non-ideal binary mixtures are distilled under total reflux to study the relationship between mass transfer coefficient and concentration. Based on the experimental data and Maxwell-Stefan equation, a mathematical model for calculating mass transfer coefficient is presented. The results show that mass transfer coefficient depends not only on the concentration of the vapor and liquid on the tray, but also on the concentration of the vapor and liquid on the neighboring tray. For highly non-ideal alcohol-water systems, the difference between the maximum and the minimum values of mass transfer coefficients is about an order of magnitude, therefore, the assumption of constant mass transfer coefficient in common design practice for non-ideal systems may lead to considerable error.

The intrinsic kinetics of catalytic hydrogenation of rosin on Raney nickel was investigated at temperature 423 K to 453 K and under pressure 4 0 MPa to 7 0 MPa. Gas hold-up and reaction in autoclaves with different types of stirrers were determined. The result showed that the catalytic hydrogenation of rosin on Raney nickel is a reaction of external diffusion control. The external diffusion effect was eliminated by adding No 200 solvent oil, changing stirrer type and increasing rotational speed. Based on the experimental results, a suitable reaction model was selected from 17 probable reaction mechanism models, i e the main component abietic-acid in rosin is not absorbed and absorption of atomic hydrogen with reaction between atomically absorbed hydrogen on catalyst surface and abietic-acid could be the controlling step. The intrinsic kinetic equation was acquired. It is useful to provide a theoretical basis for the development of industrial process.

Photocatalytic degradation kinetics of 4BS dye stuff was studied in an open batch slurry reactor with fine particulate TiO ₂ catalyst and UV light. The influences of mixing of solid-liquid and external diffusion on degradation rate were eliminated by increasing stirred rate. Favorable pH was about 3 5. Distance of light source with surface of solution was also important for photocatalytic reaction, but the effect of intensity of illumination was very complicated, so a special and acceptable light intensity was selected by changing the position of lamp. Then the experiments by changing the amount of catalyst, reaction time and initial concentrations of reactant were made.A suitable amount of catalyst was about 1 0 g·L ^-1 , and the higher the initial concentrations of dyestuff, the lower the degradation rate. According to numeric analysis for the above experimental results, the reaction kinetics was second order with respect to the concentration of 4BS, and the reaction rate was proportional to the amount of catalyst under the experimental condition. However, the rate constant was different for the catalyst amount in 0 5 g·L ^-1 or in the range of 1 0-6 0 g·L ^-1 , which was due to the change of determinanf factor for degradations. The reaction kinetics that could be used for all of the degradation process was necessary in the reactor design.

The thermal pressure coefficients and densities of six plasticizers for dimthyl phthalate,diethyl malonate,triethyl phosphate,tributyl phosphate,dibutyl oxalate,dibutyl sebacate have been measured over the temperature range of 25-85℃.The augmented van der Waals model is used to correlate the experimental data.A method of predicting the internal pressure of the plasticizers is established,and the new solubility parameters for thirty plasticizers are obtained.

The effects of several factors on boiling heat transfer around horizontal circular copper tube in an acoustic cavitation field were investigated experimentally, and the inherent mechanism of the influences of acoustic cavitation parameters, fluid subcooling and nanometer particles were discussed in terms of local wall temperature. The experimental results show that the influence of cavitation bubbles reduced with the decreasing of cavitation distance, fluid subcooling and nanometer particle concentration, yet enhanced with the increasing of cavitation intensity. Boiling heat transfer could be remarkably intensified by acoustic cavitation due to not only sufficient provision of nucleated vapor embryos to the tube surface, but also increasing boiling area and consequently effective dissipation of heat. The addition of nanometer particles in liquid could result in roughness variation of heater surface and active reduction of cavitation bubbles.

A water-to-water high temperature heat pump was fested experimentally in this work. The inlet water temperature of evaporator was 40 ℃ and the inlet and outlet water temperature of condenser were 70 ℃and 80 ℃ respectively. Almost no conveafioual refrigerant is proper for this high temperature working condition. R22/R141b was taken as heat pump working fluid firstly in this work and heat pump’s pressure performance is improved. Even though the highest cooling water temperature was about 80 ℃,the highest pressure was less than 2 5 MPa and compression ratio was less than 8, which could satisfy R22 compressor’s limits. The performance of system was characterized by refrigerant compositions, compressor RPM and water temperature change. It was found that the coefficient of performance reached its maxim of 2 5 when R22’s molar component was about 75%. If only the water temperature difference in evaporator Δ T E increased, the heating and refrigerating capacity all decreasd. However, the heating and refrigerating capacity all increased with water temperature difference in condenser Δ T C. Frequency of compressor had little influence on heat pump’s COP and working fluid’s (R22/R141b) composition if the compositions and working condition remained unchanged.

In chemical,oil refinery and power industries there are many chain energy systems.Socalled chain energy system is made up of some unitary devices chained up,and each unit is allowed to exchange energy or mass with the outside of the system.Applying the idea of thermoeconomic isolation,a new method of thermoeconomic isolation on the chain energy systems is presented,and its convergence is proved meanwhile.It is the essene of the method to achieve thermoeconomic isolation on chain energy systems that two known parameters located at the start unit and the end unit are used to adjust and determine the unknown maginal exergy cost of each unit by the way of press and squeeze,and make them converge on correct result.An example of applying the method to a nonlinear chain energy system shows that the method is effective. The method will help to break a new path to make thermoeconomic isolation be achieved in other types of energy system.