Numerical simulation of fluid-solid two-phase flows is reviewed with 105 references. There are two approaches (Lagrangian approach and Eulerian approach) typically used for modeling fluid-solid flows. The former treats the fluid phase as continuous phase and the solid phase as dispersed phase and predicts the particle trajectories in the fluid phase as the results of forces acting on particles.The latter treats the solid as a certain kind of continuum and solves two continuum equations for both fluid and solid phase. At first, as the basis of fluid-solid two-phase flow, several turbulence models, such as Reynolds Association Numerical Simulation (RANS), Direct Numerical Simulation (DNS), Large Eddy Simulation (LES) and Discrete Vortex Simulation (DVS), for the continuous fluid phase are summarized,and the mechanisms of RANS are discussed in detail. In the Lagrangian approach, a particle kinetic equation is presented and the importance of each force acting on a particle is discussed. For a flow with dense particles, various interaction models between particles are discussed , among which the Distinct Element Method (DEM) newly developed from rock deformation study is particularly described, and the new method shows great predicting ability. In the Eulerian approach, the basis equations for the solid and fluid phases as well as their numerical treatments are presented. To close the turbulence and phase related equations, calculation of solid phase viscosity and pressure are discussed respectively. Finally, a k-ε-k p model and model derived from kinetic theory of granular flow are especially introduced. As a complement, a discussion of one-way coupling and two-way coupling between fluid and solid phase is included. Based on the review of the advantages and disadvantages of all models, the existing problems and the future development direction of fluid-solid two phase flow are given as conclusions.

Experiments were conducted in the high pressure distillation column containing corrugated structured packing of Mellapak 250Y under operating pressure from 0.3 MPa to 2 MPa, using n -butane and n -pentane mixture as the separating material. The height equivalent to a theoretical plate (HETP) was evaluated from the measured n -butane liquid concentration profile along the packing. After carefully analyzed, the HETP may be reasonably divided into two parts. The first part is the ideal height of mass transfer unit, which is caused by the mass transfer resistance between vapor and liquid. Another part is the height of backmixing unit (HBU), which is caused by the backmixing of vapor and liquid. The parameters of HBU correlation were evaluated by the experimental data. The present HETP correlation was used to predict the experimental results in literature, and well agreement was found between them.

The effect of particle scattering on the absorptive characteristics of a semitransparent fluid layer is investigated by the Monte Carlo method. A one dimensional parallel plane model is used for the fluid layer. By the Fresnels equation , the refraction and reflection of spectral radiation at the semitransparent and specular incident surface are considered along with the diffusive reflection at the opaque gray wall. Several kinds of typical scattering distributions are considered with the H-G phase function for the particles in the nongray absorbing semitransparent fluid. Taken as an example, a water layer containing particles is irradiated by an incident spectral radiation perpendicular to the surface. For the various scattering distributions, the overall spectral absorptivity of the water layer is presented along with the absorptive distribution for different positions inside the layer, which is described by a spectral absorptive distribution function introduced in this paper. By analyzing the calculated results, the influences on the absorptive characteristics of a semitransparent fluid layer are investigated , which come from the scattering distribution and albedo as well as the absorbing factor of the particles . From this investigation, the following conclusions are derived. First, particle scattering can greatly change both of the overall absorptive ability and the absorptive distribution function of a semitransparent fluid layer. The influences show multi-variable and nonlinear dependence on the fluid layer optical thickness and the absorptive factor, extinction coefficient, scattering phase function and albedo of particles. Second, the optical thickness of the fluid layer and the absorptive factor of particles exert an independent and monotonous influence that the increase of either can directly enlarge the absorptivity of the fluid layer. However,particle scattering affects the absorptive characteristics by changing transfer directions of radiation in the fluid layer, thus its influence depends on the fluid layer optical thickness and the absorbing ability of particles and therefore is dependent and nonmonotonous. Third,scattering distribution reacts differently under different scattering intensity . But for different scattering distributions, the absorptive distribution function reaches peak values almost at the same depth inside the fluid layer, and the peak occurrence moves toward the wall with decrease of scattering intensity.

Synthetic tests of polyferric sulfate (PFS) is carried out in this paper. The effects of the operation temperature, pressure, dosages of sulfuric acid and catalysts on reaction rate and quality of product are investigated . The results indicate that the effect of temperature on reaction rate is like a parabola with a downward curvature, and the homologous best temperature is about 120 ℃. The reaction rate for synthesis of PFS is directly proportional to the dosage of catalysts and increases progressively with increasing dosage of sulfuric acid as well, but the rate increase will become unremarkable unless the pressure is less than 0.3 MPa. When the molar ratio of sulfuric acid to ferrous ion is in the range of 0.25—0.50, the alkalinity degree of the final product will increase with the decrease of sulfuric acid dosage. Once when the molar ratio is less than 0.25, the alkalinity degree and ferric content will remarkably decrease and a lot of ferric hydroxide precipitates.

Based upon the discussion of the diffusion and reaction processes in paper Ⅰ,including general analysis of crystal micro-structure ,substance phase and chemical contents of three kinds of phosphate ores of domestic mine(Jing He,Xiao Feng and Kai Yang),the reaction kinetics process involving phosphoric acid-phosphate ore particles was investigated in an experiment system.As a result,the new negative temperature effect of iron and alumium impurity reaction was discovered.Accompanying these special phenomena in fractal particles ,the self-ordering structrue arising in the diffusion process was demonstrated in the experiments by using scanning electron microscopy and X-ray diffraction analysis.Furthermore,the kinetic process was described by adopting the new model in paper(Ⅰ) ,and satisfactory results were obtained.

A new method is proposed for waste minimization of reactor network system according to the basic principles of attainable region method used in reactor network synthesis. By this method it is meant that, the targeting of the waste minimization is divided into selectivity, relative selectivity and instant selectivity maximization. Based on those different objective functions, the optimization calculation is carried out directly in the convex region formed by arbitrary reaction and mixing, then CSTR equation and DSR equation in two and three-dimensional concentration spaces are thus attained. In the view of geometry, the CSTR locus and DSR trajectory are the smooth connection curves of reaction and mixing process; while by physical concept, every state point in the CSTR locus and DSR trajectory are the extreme value point of selectivity and instant selectivity respectively. On the basis of these studies, its suggested that a state point in reactor system has maximum selectivity if it satisfies both CSTR and DSR equation simultaneously, and that changing along the CSTR locus or DSR trajectory, the reaction path and the production distribution can be improved.

The concept and construction method of maximum selectivity curve is presented in this paper.In the view of physical concept,any points in the curve represent the state point of the maximum selectivity corresponding to the feed point ( x 0, y 0, z 0).To reach the maximum selectivity curve from the feed point the CSTR process should be selected.According to the property of the maximum single yield curve and maximum selectivity curve,the attainable region can be divided into three sections,that is ,the continuous stirred tank region,PFR region and non-operation region.Among which the area of continuous stirred tank region would change with the kinetic conditions and even disappear completely,while the non-operation region will not exist when the parallel reaction is concerned.Based on the property of different region in the attainable region and the connection boundary,the region dividing strategy for reactor network synthesis is put up.By this strategy,it is convenient to draw up the flow structure of the reactor network to achieve the optimal object of waste minimization.

A method of solvent extraction for extracting and separating itaconic acid was developed. At first, the suitable extractants were chosen. Then, the effects of several technological parameters, the concentration of itaconic acid and pH value in aqueous phase, concentration of extractant in organic phase and temperature on extraction of itaconic acid were determined. Based on the experimental results a mathematic model was developed.

Fine particle coating was conducted by the rapid expansion of supercritical fluid solution (RESS) in a fluidized bed for release control of some key component in core particles. The supercritical carbon dioxide solution of paraffin was jetted into the fluidized bed of the core particles. The rapid phase change of the fluid solution from supercritical state to gas results in a solute at high supersaturating state in the solvent, which forms a huge number of superfine nuclei in the jetting flow. The deposition of the superfine nuclei on the surface of the core particles leads to a thin layer coating of paraffin. The size of the superfine nuclei is in the order of 40 nm. A porous spherical particle was selected as the core particle, which carried a tracer component of a kind of dye. Coating level was examined by the tracers release concentration in a solvent over a certain time. The state of coating was analyzed by measuring the average mass of coated particles and a SEM observation on the surface of coated particles. The rapid expansion of the supercritical fluid solution causes a big temperature drop at the nozzle outlet. The low temperature of the nozzle outlet affects the phase of carbon dioxide and the properties of the superfine nuclei in the jetting flow, therefore it affects the particle coating process. The effect of temperature at nozzle inlet, an important parameter, on surface coating was investigated. Seal coating was formed on the core particle surface at higher temperature. Porous coating was formed on the core particle surface at lower temperature. The temperature of the nozzle inlet affects the nucleus size significantly. Higher temperature results in a bigger size of the superfine nuclei. By controlling the operation parameters, a satisfactory quality of coated particles was achieved.

Fine griseofulvin particles formation by rapid expansion of supercritical solutions (RESS) is studied. An RESS experiment apparatus is set up based on NOVA supercritical experiment equipment. The throttle orifice was made by a stainless steel foil, which was drilled by laser. The diameter of the orifice was between 10—50 μm and its length is 400 μm. The nozzle was heated by wire and the temperature could be controlled and indicated by a thermocouple. The expansion chamber was made of glass equipped with a heating jacket, therefore the expansion backpressure can only be maintained in atmospheric pressure. When the solution flow through the nozzle to throttle and spray into the expansion chamber, griseofulvin was then deposited in the chamber. The effect of solute concentration was researched by change in temperature of the dissolution column and therefore the second solvent pipeline was not needed. All samples were observed by a microscope and a camera was used for recording. Several operation parameters were studied. At first, sampling positions in expansion chamber were tested and the results showed that it was not sensitive for the diameter of griseofulvin. Then, the effect of the diameter of the orifice, the pre-expansion temperature, the dissolution pressure, the temperature of expansion chamber, the nozzle heating and the concentration of griseofulvin on the diameter of griseofulvin were studied. The results show that the smaller the orifice diameter is, the smaller the griseofulvin particle is.The higher the temperatures are, the smaller the particles are.The solubility of griseofulvin in supercritical CO 2 is in the converse condensation region. Thus, higher temperature will cause high supersaturation rate and increase the nucleation rate.It means that the particle size will be reduced. Moreover, it must be some degree of supersaturating in pre- expansion section because the fluid should be heated to a higher temperature before entering the nozzle to keep the fluid in single-phase area at the throttle. The supersaturating would have caused a few griseofulvin deposited before the nozzle but the experiment confirmed that at 25 MPa griseofulvin will never be deposited even though some supersaturating values exist. Also,as indicated by other papers,the experiment results pointed out that reducing the solute concentration before nozzle will form large particles. Therefore, 0.8? ?.8 μm griseofulvin particles can be formed by RESS,when the dissolution temperature ranges from 308.2 to 313.2 K,the dissolution and pre- expansion pressure is 25 to 30 MPa,the pre-expansion temperature and nozzle temperature is 308.2 to 323.2 K,and the expansion chamber temperature ranges from 303.2 to 313.2 K .

As a kind of energetic material, propellant can be decomposed and heat can be generated. If the heat is not released in time but is accumulated,self-ignition would take place. For example, the self-ignition of two kinds of propellants stored in a experimental site was reported.It is proposed that self-ignition of one of them took place first and ignited the other. In this paper, two kinds of propellants self-ignition of which had taken place are studied numerically.The mathematical model of heat accumulation is established under the condition of heat insulation.The self-ignition time is calculated,and the result is discussed and analyzed. It is determined that self-ignition took place in propellant No.1 first, then propellant No.2 was ignited. The critical temperatures of two kinds of propellants under the condition of heat insulation are obtained.

Taxol is a unique antitumor drug that appears to exert its activity as a result of interference with microtubular structure and function. The Taxol solubility of in methanol, ethanol and methanol-water was measured by the equilibrium method in this paper. The data obtained were correlated by the regress equation and ANN model. The results showed that the both were in excellent agreement with the experimental data and the ANN model was more convenient than the regress equation.

The strength of flammable gas cloud explosion has been experimentally researched by means of acetylene-air clouds which were ignited by electric sparks.The ignition device which provides ignition energy of about 100mJ was made according to international standard ISO 6184 and American Standard NFPA68. The explosion pressure was picked up by pressure transducer with a dynamic responding time of 0.001 s and recorded by computer. By regressing the experimental data,the relationship of gas cloud explosion pressure to the initial radius of gas cloud and the distance to the center of gas cloud can be obtained. That is p=Ar 2 0/r where A is a constant depending on flammable gas cloud.The damage of unrestricted gas cloud to building structure is discussed based on the strength of houses.

For the gas and liquid superficial velocity ranging from 0.07—0.36?m·s -1 and 0.008—0.016?m·s -1 respectively,the significance of operating conditions on the macro-characteristic properties,such as liquid holdup,pressure drop,pulsing velocity and pulsing frequency etc ,are investigated through experiments.Based on the 130 dynamic liquid holdup data a new correlation is proposed for the dynamic liquid holdup as: β d=1.324· γ·Re l 0.057 ·Re g -0.332 ,and correlation of the pressure drop is shown as: Δ p Δ L=∑iA i(1-ε) 2a 2 vε 3μ iu i+B i(1-ε)a vε 3ρ iu 2 i ,where A l=3.84×10 -3 ,A g =9.33×10 -3 ,B l=7.0×10 -5 ,B g =1.59×10 -4 .A new type of corcentric ring conductance probe was used to measure the conductance fluctuation in the trickle bed reactor packed with 4—5?mm glass beads.The pulse velocity and frequency are calculated based on the time series data.Correlations of the pulse velocity and pulse frequency were obtained as V p =1.575u g 1.98 1-0.0864u g 12.01 (1-17.668U l)and f= -2.505 +5.113U g +2.04×10 2U l,respectively.All the correlations have high accuracy in predicting the parameters.

ZrO 2(Y 2O 3) powder and SiC nanopowder were prepared by carbothermal reduction of ZrSiO 4. With the existence of additive Y 2O 3 and other impurities, ZrSiO 4 was dissociated into ZrO 2 and SiO 2 in the condition of 1450—1550?℃. ZrO 2(Y 2O 3)powder was thus obtained via the removal of SiO 2 as silicon oxide (SiO) gas during carbothermal reduction process. SiC nanopowder and small amount of SiC whisker were synthesized form the gas-phase reaction between SiO vapor and supplied CH 4 gas.

Natural gas is not only playing an increasing important role in energy and chemicals supplies in 21st century but is also the second most important component of the greenhouse gases. Clean and direct conversion of methane to C 2 hydrocarbons (ethane, ethene and acetylene) through AC and DC plasma catalysis enhanced by electric field was studied at low temperature ranging from 50?℃ to 100?℃, atmospheric pressure and low power conditions. The influence of form of the electrode, distance between the electrodes, voltage, diameter of reactor, flow of inlet methane, N 2/CH 4(mole) and 20 catalysts were tested under low temperature plasma. The results indicated that best form of the electrode was plate; the better distance between the electrode was 5mm; the appropriate voltage was 38V(AC);the apparent diameter of reactor was 17mm, the likely flow range flux of inlet methane was 60—80?ml·min -1 , the suitable ratio of N 2/CH 4 (mole) was 0.5—1.0.The yield of C 2 hydrocarbons was the highest on V 2O 5,ZnO(5%)/ZSM-5-38 catalyst, the yield of ethene was the highest on La 0.8 Sr 0.2 CrO 3,ZnO catalyst. The results are better than those obtained through conventional reaction of oxidation coupling of methane.

The influences of temperature, pressure, catalyst content, H 2O 2 content and mol ratio of propylene to H 2O 2 on epoxidation of propylene with H 2O 2 over TS-1 in a small-scale three phase loop thermosphonic reactor were investigated. The proper reaction condition was determined as follows: mol ratio of propylene to H 2O 2 was 1.1—1.3, temperature was 30—45?℃, reaction temperature rise was below 15?℃, pressure was 0—0.1?MPa, catalyst content was 3%—6%,and H 2O 2 content was 3%—5%.The conversion of H 2O 2 is above 94%,and selectivity of propylene is up to 96%. At these conditions, the yield of PO is higher than a figure of about 80%,which is achieved using conventional reactor. This reactor can realize catalyst regeneration continuously. This viable reactor can also be applied in other oxidation processes using TS-1, i.e. hydroxylation of phenol, ammoxidation of cyclohexanone.The results will lay a foundation for the development of the reactor in propylene epoxidation process.

In batch cultures of Candida krusei , the effect of corn steep liquor (CSL) concentration was investigated. The result showed that glycerol yield was greatly affected by CSL concentration. Higher glycerol yield was attained when the initial CSL concentration in the medium was 9?g·L -1 . The fermentation kinetics were studied and the parameters for cell growth, maintenance, and glycerol production were obtained. Material balance revealed by product formation during the growth phase and suggested a fed-batch culture strategy.