With the development of high-technology,molecular simulation,which is novel both in theory and experiment,has been applied in chemical engineering.The new technologies in chemical industry include such complex materials as polymer and electrolyte,such complex conditions as critical and super critical,and such complex phenomenon as interface, membrane and solution.To achieve the vision of completely automated product and process design in chemical industry, the properties of the materials and the mechanism of the phenomena should be accurately obtained.The expectations for molecular simulation are very high, because it has been identified as one of the key methods for determining these properties and phenomena.In this paper, the key problems of molecular simulation in chemical engineering especially based on molecular dynamics (MD) and quantum chemistry (QC) are discussed.They include potential model of MD, scale of MD, the connection of muti-scale MD, analysis of MD results, construction of a reasonable initial configuration and software & hardware of MD.Several promising guides are proposed to solve the above key issues.Computational quantum chemistry software such as Gaussian 98 could be utilized to acquire the missing interaction parameters.As for potential model it is not necessary to use the most complex one to describe the interaction between particles.Sometimes simple models are good enough to calculate certain properties.Some new techniques are developed to enlarge the system of MD at different scales.For example, the density functional theory (DFT) made the QC calculation for hundreds of atoms possible while dissipative particle dynamics (DPD) extended the system of MD to mesoscale.The general trend of molecular simulation is to combine QC, MD and mesoscale dynamics more closely, and many muti-scale MD methods such as Car-Parrinello MD (CPMD) would definitely become stronger and stronger.It is indispensable to define a suitable statistical variable to analyze the trajectory of MD, and the trick of definition is to deal with the specific situation in a special way.Normally initial configurations of MD are not the images of real systems but the abstract of real ones.Real systems must be reduced to different extents according to different goals.Sharing the MD codes and applying parallel computers could be regarded as the most promising solutions within the limitations of software & hardware of MD.

Heavy oil was separated into over dozen cuts under a lower temperature(<250℃) to avoid thermal cracking by the supercritical fluid extraction and fractionation method (SFEF).The properties and ¹H-NMR，¹³C-NMR spectra of the fractions were measured to determine their structure parameters and construct average molecular models.The boiling points of heavy oil fractions were measured up to 950 K.Based on Rarey’s group contribution model recently published, 12 groups were defined for heavy oil cuts.It was found that Rarey’s model was accurate for below C₅₀ fractions but show higher errors for heavier cuts.The dependence of boiling point on total atom number (except hydrogen) was refitted, while the value of the original group kept unchanged.Estimation for boiling point of two different residua from Russian crude oil and a mixed crude oil of Daqing(70% in mass) with Russian(30% in mass) was found with an average deviation 1.4% in the range of 600K to 950K.The Tb prediction of normal alkanes from C₃ to C₁₂₀ was also found in good agreement with literature data.It verifies that the group definition and structure expression for heavy oil fractions are reliable.The group contribution method combined with SFEF can extend Tb estimation up to 1050 K with carbon numbers over 100.

A novel model was presented to describe the mass transfer from an oscillating microdroplet.Based on the periodical flow field induced by an oscillating microdroplet and the basic mass transfer conservation equation, a simplified mass transfer control equation was derived and the corresponding concentration distribution was obtained by means of numerical technique.The simulated results showed the uneven characteristics in the concentration distribution.The gradients of concentration on upwind side of the microdroplet were much greater than those on downwind side.The simulated average Sherwood numbers and the rates of mass transfer were increasing with increasing oscillatory frequency.The trends of simulated Sherwood numbers were consistent with the experimental results of evaporation of an oscillating dodecanol microdroplet in the nitrogen media at a low evaporation rate, where the microdroplet was electrodynamically levitated and forced to oscillate in a nearly sine pattern along the central axis of an electrodynamic balance.The average error of predicted Sherwood numbers was 39.5%. It indicates that the present model is capable of describing the phenomena of mass transfer from the surface of a single oscillating microdroplet.

At present, the working fluid R22 is often used in refrigeration and heat pump systems, but it will be replaced in the next several years because its ozone-depletion potential (ODP) and global-warming potential (GWP) are very high.In order to seek some novel working fluids to replace the R22, some experiments on a small refrigeration and heat pump system were performed, and the working conditions were decided at different water temperatures and flow rates in condenser or evaporator,which were compared with those experimental data of R22 in the same working conditions.The non-azeotropic mixtures working fluid R290/R600a/R123(50%/10%/40%,mass) may become an alternative of R22 for heat pump application.

Rectangular jet is common in many engineering situations.To predict the flow field near the nozzle precisely is of great importance because it decides the development of the whole flow field.Although a series of studies have been carried out, it is not very easy to know the flow field clearly due to the complexity of rectangular jet.A large eddy simulation was conducted to investigate the flow field near the nozzle of a rectangular jet with Re=11435.The saddle shape of velocity was proved by simulation.Self-similarity flow mechanism of the streamwise velocity was shown on the central plane of y=0 when x>6D_e.The flow field of rectangular jet was similar with a round jet when x>8D_e.The simulation results fitted well with experiments.

Several important principles for designing the structure of the gas-solids entrance for the circulating fluidized bed down-flow reactor(downer)were proposed based on summarizing the existing investigations.A new entrance structure based on strong turbulence dispersion was designed and tested on a semi-industry downer cold model with 418mm I.D. and 18m height.Inside this new type downer entrance, a strong turbulent flow field, which was introduced via the impinging of high velocity gas flows in opposite directions,could make the gas and solids mix well quickly.The gas-solids flow and mixing behavior inside the entrance as well as in the downer main bed were studied by using the dual-optical density probe, Laser Doppler Velocimeter (LDV), micro-manometer and the steady state hydrogen tracing technique.Results showed that compared to the traditional downer entrance structure based on the jet flow from single-tube or multiple-tube, although there was no gas-solids distributor for this new downer entrance, it could quickly make the gas-solids flow with high flux rate be well distributed, indicating that this downer entrance could be a potential excellent entrance for industrial downer reactor.

Experiments on shock waves interacting with a loose particle bed were conducted in a shock tube.The incident shock velocity and particle diameters were measured by pressure transducers and Malvern particle sizer respectively.The flow fields both in gas and granular phase induced by shock waves were recorded by means of shadow graphs and pulsed X-ray shadow graphs with trace particles.The particle motion was strongly controlled by particle-particle collision which was associated with fluctuation kinetic energy of particle.Based on kinetic theory of granular flow,the conservation and constitutive equations for a dense two-phase flow were derived by introducing “granular temperature”,and then numerical simulations were performed by using ASUM+ schemes with the advantages of combining the efficiency of Flux-vector splitting and the accuracy of Flux-difference splitting. Measured and calculated results were in good agreement.

A set of equipment of real-time measurement of aerosols concentration was established to survey of the diffusional and migratory behavior of aerosols in diffusion batteries by using aerosol counting instruments and chromatography analysis.Measurements of mean residence time and penetration of submicrometer aerosols in flows in tubes were made within the range of Reynolds numbers from 0.07 to 0.26 by widening of aerosols pulses analysis of monodisperse polystyrene spheres solid particles injected in clean nitrogen flow through a diffusion battery of capillary tubes.It was shown that the penetration of aerosol significantly depended on the mean flow velocity and particles size.On the other hand, the mean aerosol velocity weakly differs from the mean flow velocity.The results obtained were important in several applications, including aerosols sampling, detection and leakage evaluation.

Flow regime identification of gas-solid fluidized bed has been a difficult problem in fluidized field.Up to now,it is almost impossible to recognize all the flow regimes with a single sensor or parameter because of the inner complexity of the pressure signal of gas-solid phase system and the existence of transition.A new regime-division method is proposed in this paper.Fuzzy language“membership”is used to describe the degree of transition.Algorithmic complexity C(n) and fluctuation complexity Cf of the pressure signal of a seperate sensor are used as nonlinear characteristic parameters to indicate the flow regimes.Simplified models of C(n) and Cf to identify the flow regimes are established according to observation and statistics of experiments.Membership functions are given to indicate the flow regimes according to the simplified models.Data fusion at the feature level is carried out through fuzzy transformation and the identification result of a separate sensor is obtained.Data fusion at the decision level is carried out in the same way and the initial identification results are input into the decision center as local decisions.Finally the identification result of multi-parameters and multi-sensors is obtained.The experimental results show that multi-sensor data fusion can well identify the fluidized states.

In order to find the characteristics of gas flowrate increasing transient under the slug flow regime,a statistical investigation was carried out in a 378 m long, 80 mm i.d. stainless steel pipeline. Air and water were used as test fluids and responses to change of gas flowrate were measured by using a series of pressure transducers. Differential pressure signal was obtained by subtracting downstream pressure signal from upstream pressure signal.According to the test results, the development trends and statistical characteristics of pressure and differential pressure along the pipe during the transient process of gas flowrate increasing was analyzed.An equation for the calculation of pressure overshoot was proposed for this transient process.

The kinetics of dechlorination of Ca-based sorbents was explored in this paper, in order to confirm the factors that control the reaction rate in the combustion.A shrinking core model of nonporous CaO-HCl was built.From this model, the effects of such factors as reaction temperature, reaction time, concentration of HCl, particle size of CaO on dechlorination characteristics were studied.The results showed that the model fitted experimental results, so the model could reflect the course of dechlorination well.

It is derived that the varying manner of instantaneous constant composition region with batch distillation of a binary ideal mixture under constant reflux ratio and ideal operating condition is determined with the numeric of f(x_F)［Eq.(15)］ by setting up the function f(z)［Eq.(12)］,and its algorithm of minimum reflux ratio can be improved.This paper analyzed the cause leading to high energy consumption of batch distillation under constant reflux ratio to meet the demand for a high light distillate composition and high average concentration of light component in the overhead product as compared to the case of operation with a constant distillate composition.

Principal component analysis (PCA) finds wide application in chemical process monitoring and product quality control as a data-driven modeling method.Based on the concept on fault subspace, the fault reconstruction issue was explored by using T² index, while the geometric method recently developed by Dunia et al focuses on the SPE index.However, some faults involving process fault and sensor fault that do not violate the PCA statistical model can only be detected by T² index.Thus the proposed reconstruction approach has superior performance in the general sense.The acquired results were then illustrated and verified by monitoring a simulated double-effect evaporator (DEE) process, where different sensor faults were reconstructed and fault wave/magnitude was estimated to judge the sensor fault type.

In this paper, automatic differentiation is applied to sensitivity analysis in distillation column optimization.Sensitivity analysis was aimed to estimate the influence with the presence of uncertainties in distillation column optimization.The column was modeled in semi-open-equation manner.Automatic differentiation(AD) and implicit function differentiation rule(IFDR) were used to calculate the precise absolute and relative sensitivity coefficients, with no truncation error introduced.The proposed approach was verified in sensitivity analysis of a practical distillation column optimization. Its result was compared with that of the finite difference (FD)method.This approach is not only error-free, but also of general purpose.

The asymmetric reduction of 2-octanone to 2-octanol by yeast in aqueous phase was investigated.The reduction product was mainly S-2- octanol.The results indicated that the conversion ratio of 2-octanoe and the enantiomeric excess values of product were both satisfactory for asymmetric reduction.It was shown also that in the catalysis of the ketone reduction the co-substrate was required to regenerate the NAD(P)H.The appropriate condition to the reaction was 30 ℃ and pH 3.0 or pH 7.0. The high concentrations of substrate and product would have some toxicity to the yeast cells and the high concentration of 2-octanol would inhibit the reduction reaction.When too much S-2-octanol existed in the medium, the S-2-octanol would be oxidized to 2-octanone by yeast, which showed that yeast could be a biocatalyst not only for reduction of 2-octanone to S-2-octanol, but also for oxidation of S-2-octanol to 2-octanone.

Refolding of lysozyme(LYS) by directly dilution with refolding buffer containing CTAB was performed and the optimal recovery of lysozyme activity was obtained at the molecular ratio of CTAB to lysozyme of 10, in case the denatured lysozyme concentration was over 0.2 mg&#8226;ml^-1.Characterization of the structure of the complex formed by CTAB and denatured lysozyme was carried out by means of surface tension measurement, ion-exchange chromatography, fluorescence spectrum, and non-reductive SDS-PAGE.The diversity of the complex was identified by the changes of surface tension, elution behavior in ion-exchange chromatography, as well as the electrophoretic migration in the non-reductive SDS-PAGE, all of which was shown to be a function of the molecular ratio of CTAB to protein.The changes of the composition and structure of the CTAB-protein complex were identified, as shown by the yield of lysozyme activity as a function of incubating time.The above results are of fundamental importance for the development and application of surfactant assisted protein refolding.

Oxidative refolding of denatured-reduced lysozyme at 5 mg&#8226;ml^-1 was performed by fed-batch operation with dilution additives(acetamide and glycerol).A kinetic model based on the three-state protein model was established to describe the refolding process, and the refolding and aggregation constants were obtained by fitting the model to the experimental data.At a lower GdmCl concentration (1 mol&#8226;L-1) and a proper acetamide concentration (5 mol&#8226;L^-1), the refolding of lysozyme could reach a yield higher than 80%.When GdmCl concentration was decreased, acetamide concentration should be properly increased to achieve a high refolding yield.This indicated the same effect of acetamide and GdmCl on protein refolding.In contrast, glycerol facilitated the refolding of lysozyme by enhancing the thermodynamic stability of native-state protein.This meant that glycerol was cooperative with GdmCl on facilitating protein refolding, and its addition could only give a high yield at a proper GdmCl concentration.

A SA/NaCS-CaCl₂/PMCG microcapsule which can be used in biotechnology was prepared.The production of nattokinase from Bacillus subtilis immobilized in SA/CS-CaCl₂/PMCG microcapsule was studied.The effects of PMCG on the growth of Bacillus subtilis were investgated.The growth rate, consumation rate of xylose and production rate of nottokinase of microencapsulated cells were compared with suspension culture.The results showed that immobilized cells grew as suspension culture for a single batch.The encapsulated fermentation had advantage in multi-batch culture.The highest activities of 2465 IU&#8226;ml^-1 of nattokinase were reached, which was 2 times higher than that in suspension culture.

The effect of each composition in catalyst ink on the performance of fuel cell was studied with the catalyst layer prepared by the directly printing catalyst on membrane technique.Isopropanol was the solvent and pore forming agent in catalyst ink.When the ratio of catalyst and isopropanol in catalyst ink was equal to about 1∶10, the performance of fuel cell was the best.Nafion was used both as a good binder and proton conductor in the catalyst layer.For the directly printing technique,direct application apparently improves the interfacial continuity between the Nafion ionomer in membrane and the Nafion ionomer in the catalyst layer.It was shown that the optimum content of dry Nafion (NFP) was about 33%.The effect of different Pt contents of Pt/C catalysts on the performance of fuel cell was investigated, and the optimum content of isopropanol and dry Nafion were determined based on different catalysts respectively.Finally the effect of different catalyst layers on the performance of fuel cell was studied.The more the catalyst layers,the better the performance of fuel cell with minor difference between catalysts.

The ζ-potentials of five kinds of Chinese typical steam coals with different ranks in aqueous solution with different pH values and the effects of H₂O₂-oxidation on ζ-potential of the corresponding coals were measured.The pH values at the isoelectric point (IEP) of the coals were determined.The functional groups related to the coal surface potentials and their changes by H₂O₂-oxidation were quantitatively characterized using FTIR.The adsorption energy of H⁺ on different coal surface, along with correlated chemical bond length, order, and net charge distribution were obtained by means of ZINDO quantum chemical calculation of model compounds.According to a comprehensive analysis of ζ-potential, FTIR spectra and the results of ZINDO calculation，the following conclusions were reached.Coal surface is negatively charged in aqueous system.IEP rise regularly with increase in coal rank,—OH is the main negative functional group closely related to ζ-potential on coal surface.After H2O2-oxidation, the contents of —OH,—COOH groups and negativity of coal surface increase.Chemical adsorption of H⁺ occurrs on coal surface, and the adsorption energy increases with increase in coal rank.

The reaction between hydrogen and organic sulfur in semi-coke at high temperature was studied in this paper.Crashed and sieved semi-coke sample (with particle size of 15 μm) was placed in 5 g batches in a 22 mm I.D. differential reactor.The release of hydrogen sulfide at run temperature and under different hydrogen atmospheres was followed by hydrogen sulfide detector.The residual was analysed for sulfur.Results showed that the desulfurization of organic sulfur in semi-coke powder could be described much better with the random pore model than with grain reaction model.Grain reaction model is only adapted to the initial stage of organic sulfur removal from semi-coke powder under hydrogen atmosphere while the random pore model is adequate for the whole stage.Experiment and theoretical study also disclosed the possibility of transformation of organic sulfur to heterocyclic organic compounds such as thiophene.

Catalytic pyrolysis of biomass materials was carried out by using a powder particle fluidized bed(PPFB).Three kinds of wood-chips were used in the experiment.Four kinds of catalyst particles were used as bed medium particles and the effect of catalyst on pyrolysis products was investigated.It was found that in the primary pyrolysis of wood, most of the volatile matter was volatilzed at a temperature of 700 K and yields of light aromatic hydrocarbons,i.e., benzene, xylene, toluene and naphthalene(BTXN), increased with an increasing pyrolysis temperature.BTXN yield reached 3.1%(mass),daf at a temperature of 1173 K.When wood-chip was pyrolyzed in a fluidized bed of Zn(3%,mass)/HZSM-5 particles under a hydrogen atmosphere,BTXN yield of 6.1%(mass),daf［BTX:5.5%(mass),daf,N:0.6%(mass),daf］was obtained at 853K.For the ease with the NiMo-A,catalyst the pyrolysis products were almost methane, because its hydrogenation activity is very high.

Single-walled carbon nanotubes (SWCNTs) were prepared from coal by the arc discharge method with iron, nickel or a mixture of nickel and lanthanum as catalyst.The SWCNTs were characterized by scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray analysis, X-ray diffraction and Raman spectroscopy.The results showed that the purity of SWCNTs derived from coal was quite good, of which the diameters were closely related to the catalysts used, which was around 1.2—2.2 nm for iron catalyst; while in the case of nickel and La-Ni mixture catalysts, the diameters of the as-grown SWNTs were similar and in a range of 1.26—1.50 nm.Trace amounts of other elements such as Al, Si, Ca and K were found in the SWCNTs, which were believed to be from mineral matter in the raw coal.

Two kinds of titanium-containing mesoporous molecular sieves Ti-MSU-1 and Ti-MSU-2 were synthesized by using nonionic surfactants C₁₈(EO)₁₀ or C₁₂Ph(EO)₁₀ as templates respectively, TEOS as silicate source, TBOT as titanium source, ethanol and isopropanol as cosolvents.Structures of the synthesized molecular sieves were measured and characterized by XRD, FT-IR, UV-Vis, elemental analysis and N₂ absorption-desorption methods. Hydrothermal treatment in an autoclave of the molecular sieves precursor could help to enhance the symmetry and the ordered degree of the mesoporous structures of Ti-MSU-1 molecular sieve.However, the same method could not modify the mesoporous structures of Ti-MSU-2 molecular sieves remarkably.Both Ti-MSU-1 and Ti-MSU-2 molecular sieves showed catalytic activity to oxidation reaction of styrene.Conversion of styrene increased with increases of Ti content in the molecular sieves framework.Catalytic oxidation performance of Ti-MSU-1 was comparable to that of Ti-MSU-2, which corresponded to similar pore structures.

In a water-hydrocarbon fluid consisting of water and nonane,anti-agglomerants composed of two kinds of nonionic surfactant were tested in a visualized high-pressure sapphire apparatus.The results showed that they were effective for preventing methane hydrate from agglomerating and their concentrations in the system did not exceed 0.8% of water mass and the degree of supercooling they could tolerate reached 17℃.The performance of the compound anti-agglomerant was improved greatly compared with the one-component ones(concentration:0.5%—3% of water mass; the degree of supercooling: below 12℃ ).Finally, the mechanism was discussed.

Some successful vapor-liquid equilibrium(VLE) mixing rules based on excess free energy models proposed in recent years combines the advantages owned partially by equations of state and activity coefficient models to obtain the better prediction for nonpolar and polar systems.The paper coupled with the merits of MHV1 mixing rule, LCVM mixing rule and WS mixing rule to put forward the new two-parameter mixing rule which satisfies the second viral coefficient boundary condition.The new mixing rule, coupled with the PR equation of state and the NRTL model is tested against 18 kinds of vapor-liquid equilibrium data of nonpolar, nonpolar-polar/polar-nonpolar,and polar-polar systems.The test results indicate that the new model can yield better prediction.Compared to the other two mixing rules (WS,MHV1), the new model shows better VLE prediction capabilities of binary mixtures.

Liquid flow behavior, such as velocity distribution, in the packed column is of considerable importance in determining column performance. Using the volume-averaged method, a computational fluid dynamics(CFD) model was proposed to describe the liquid flow behavior in a structured packing column where the gas phase is stationary.A column packed with Mellapak 350Y had an inside diameter of 150mm and a height of 1000mm was simulated by solving the flow equations.A commercial CFD code, PHOENICS 3.3, was used to predict the fluid dynamics behavior of the liquid phase flow.The simulated profiles of pressure, velocity and concentration of the tracer were presented.The axial backmixing coefficients evaluated by the CFD results were presented and compared with the experimental data and the relative deviation was 3.8%—36.8%.

Mixing, achieved mostly by mechanically stirring, is one of the most important unit operation processes in chemical and related industries. The problem of design and scale-up of stirred tanks has been tackled mainly by means of semi-empirical methods.Measurement and numerical simulation of viscous fluid in a stirred tank is still unsufficient and further development is needed.In this paper, computational fluid dynamics (CFD) simulation and digital particle image velocimetry (DPIV) measurement have been carried out to study the flow field of viscous fluid in a stirred tank agitated by a four-blade Ruston turbine.The working medium is a mixture of water and glycerine with various concentrations.The results show the mean velocity, turbulent energy, vorticity and circle flux of the fluids as well as the change of flow patterns with the fluid viscosity.CFD code of CFX with sliding grids was used to simulate the flow field.The k-ε model and laminar model was selected as the models of simulation.The CFD simulations were compared with the experimental DPIV data.The result shows that the CFD simulations can reflect the flow of the viscous fluid in a stirred tank.

The co-cracking of natural gas and coal by a 15kW nitrogen(N₂ flux:2m³&#8226;h^-1) thermal plasma jet was investigated experimentally.For comparing with the cracking natural gas or coal separately, the experiments were arranged as following: （1）Cracking of natural gas;（2）Cracking of coal;（3）Co-cracking of natural gas and coal.Under the same experimental conditions, especially the same power, the experiments show that co-cracking can lead to more output of acetylene and ethylene, even more than the sum of that from（1）and（2）.The analysis shows that,during the co-cracking process, the natural gas and the coal both acquire the effect of cracking separately; the surplus output may probably be resulted from the interaction of hydrogen and carbon. Here, the hydrogen is resulted from cracking of natural gas and the carbon——from cracking of coal.

In this paper,the effect of branching and crosslinking structure on the impact strength was studied using self-plastication and post self-plastication.And the effect of self-plastication on storage performance was also discussed.Finally,the impact strength and storage property were both improved using the post self-plastication method, and the best saturated fatty acid,including it[DK]’s dosage was identified.