Organic/inorganic composite membrane is a new research topic in the membrane technology.In this study,the method of polymerization pyrolysis was adopted to modify the substrate and dip coating was used to prepare polymer/ceramic composite membrane.The effects of various factors on the process of membrane preparation were studied by orthogonal design.The selectivities of oxygen to nitrogen in both silicone rubber/ceramic and PPESK/ceramic composite membranes prepared are tantamount to intrinsic selectivities of the corresponding pure polymers separately,showing that the defect free polymer/ceramic composite membranes were successfully synthesized.The composite membranes possess good thermostability,which could lead to commercialization in both gas separation and membrane reaction at a relatively higher temperature.

Predesilicification-bauxite dressing-Bayer process is a new technical process in alumina industry proposed firstly in the world. The study on the disaggregation between alumina mineral and silica mineral in the predesilicification presents the theoretical basis for the new process. The study on the different reaction features of hydrated sodium aluminosilicate produced in different temperature with additive lime in atmospheric pressure provides the theoretical basis for its technical and economical feasibility. Some key techniques such as avoidance of bauxite over grinding and gradation of the small particles in bauxite dressing are investigated. The method of the new process in use is mentioned.

The conventional Generic Model Control (GMC) has no ability to handle the constraints explicitly, which limits the industrial application of this nonlinear control approach. In this paper, after introducing an approximate model based predictor, we present an optimization algorithm which is based on quadratic programming, with the ability to handle the linear constraints of manipulated and controlled variables and their moving velocities. After that, by combining the proposed optimization algorithm with the control law of GMC, a novel approach to the constrained Generic Model Control based on quadratic programming is developed. The proposed approach was compared with the nonlinear programming based constrained nonlinear control approach and with the nonlinear quadratic programming based dynamic matrix control approach via computer simulations,which demonstrated the effectiveness of the proposed approach.The proposed approach can be used in real time,and has the potential in industrial application.

Process monitoring is one of the most important problems in modern industrial processes. How to extract the operating features from the measurement data, determine the change of operating region according to the extracted features and infer its effect in real time is the key problem of process monitoring.Extraction of the qualitative features from process measurement signals with wavelet transform has been studied and a model based approach for casual reasoning is proposed to deduce the causality of the extracted qualitative features. The deductive results are applied to real process monitoring. The theoretical analysis and application results show that the proposed method can effectively describe the process behavior knowledge in multi scale and eliminate the virtual character of expert system in describing the time states. Therefore the proposed method improves the reliability of real time process monitoring system.

The scheduling problem of serial multiproduct batch processes which attracts more and more attention in recent years is difficult to solve by some exact mathematical methods such as mixed integer programming (MIP) methods or branch and bound (BAB) when the size of the problem is large.This is mainly due to its NP complete nature.Simulated annealing (SA) has been proved to be efficient in finding an optimal solution for this kind of problem,but it requires considerable computing time for large problems.In this paper,an improved SA algorithm is proposed for solving the addressed scheduling problem for serial multiproduct batch processes with unlimited intermediate storage (UIS).The key to the improvement of the algorithm is the adoption of a non equilibrium and repeated annealing strategy,as well as various methods for generating neighboring solutions.Compared with presently available simulated annealing algorithms,the proposed algorithm gives better solution and runs faster in solving the addressed scheduling problem.Even for a very large scheduling problem,it can get reasonable result in acceptable computing time.The method appears to be promising for scheduling serial multi product batch processes.

In this paper, a new optimization method——chaos optimization combined with exact non-differentiable penalty function is proposed for solving chemical process optimization problems which are often regarded as nonlinear constraint optimization problems.The construction of the non-differentiable penalty function is convenient, and chaos optimization method does not need continuity and differentiability of the optimization problems, so the constraint optimization problems can be first transformed into non-constraint ones by virtue of non-differentiable penalty function, and then be solved by chaos search method. The newly proposed method is applied to benzene-toluene flash vaporization process optimization for simulation study. Results show that, the new method is not only simple and easy to implement, but also has both high accuracy and reliability. It is an effective way for solving chemical process optimization problems.

Wavelet analysis is a rapidly developing domain of applied mathematics. It has been used in turbulence, and several methods are presented to study the coherent structure in turbulence. In this paper, two conclusions are made from the relation between wavelet energy spectrum and Fourier energy spectrum. The first conclusion is that the peak height of wavelet energy spectra of sine and cosine waves is proportional to their scale, and the second is that the peak width of wavelet energy spectra of sine and cosine waves is proportional to their scale. Based on wavelet analysis and these two conclusions, a new energy maxima criterion of coherent structure, P(a m)/ a m=max a >0 P(a )/ a , where P is wavelet energy spectrum, which can extract several coherent structures of close scale in turbulence and determine their scales, is presented. At the same time, Morlet wavelet is found to have a higher resolution ratio than Mexican hat wavelet and some orthonormal wavelets, such as Daubechies, Symlets, Meyer and Coiflets, which can distinctly distinguish fundamental wave from subharmonic. So Morlet wavelet is much suited to detect coherent structure in turbulence. The new criterion is validated with simulative signals which are constructed by adding three kinds of noises with different energy spectra exponents (r=0, 1.00, 1.67) to y=sin(16π x )+sin(32π x ) and keeping the intensity of coherent structure about 0.1. The results show that the new criterion can distinguish fundamental wave from subharmonic based on simulative signals with a small coherent structure intensity. At last, the new criterion is validated with three-dimensional fluctuation velocities of a round jet flow near the nozzle exit. The results show that the scale of coherent structure determined by the new criterion is equivalent to the integral scale, and the coherent structure is a large vortex.

The wave shape of coherent structure in turbulence can be reconstructed with inverse wavelet transform according to its scale. A new equation, which can more truly reconstruct the amplitude of coherent structure, is presented on the based of the analysis of wavelet transform. Morlet wavelet has a high resolution and can distinguish fundamental wave from subharmonic, however, it can not eliminate the disturbance of high frequency signals. The resolution of orthonormal wavelet is low, but it can eliminate the disturbance of high frequency signals without any other digital filter due to its orthogonality. Therefore, a new equation is presented utilizing the peculiarities of Morlet wavelet and orthonormal wavelet, which is f(x,a)=1H Ψ 1Ψ 2 ∫ +∞ -∞ (W Ψ 1 f)(b,a) Ψ 2a,b (x)1a d b, where a=a m,Ψ 1 is Morlet wavelet,Ψ 2 is a orthonormal wavelet. This equation can not only reconstruct the wave shape of subharmonic, but also overcome the interference of high frequency noise. Based on the character of wavelet analysis, a research method of local singularity of coherent structure is presented. In this method, local intermittency measure of a orthonormal wavelet at coherent structure scale is used to determine the position of a singularity in the coherent structure, and the Mexican hat wavelet modulus at the neighborhood of half the scale of coherent structure is used to calculate every exponent. At last all exponents are averaged by α= ?α(x i)? i . This algorithm can calculate the structure exponent of coherent structure in turbulence. The conclusions are validated with simulative signal and the results show that the reconstruction equation can be used to truly reconstruct the wave shape and amplitude of coherent structure and be used to calculate the structure exponents of coherent structure, though there is strong disturbance of high frequency signals. At last, the conclusions are validated with three-dimensional fluctuation velocities of a round jet flow near the nozzle exit. The results show that the structure exponent of coherent structure is about 1.6.

There are some puzzles in the polymerization of propylene on heterogeneous Ziegler-Natta catalysts. The broad molecular weight distribution (MWD) of polypropylene might be caused by two reasons. The first reason is the diffusional resistance by polymer around the active sites. The second reason is the presence of more than one kind of active sites on Ziegler-Natta catalyst. Both of the two reasons have been tested experimentally, but no general explanation has been generally accepted. A new kinetic model, namely Uniformly-distributed Multigrain Model (UMGM) is proposed to explain the broad MWD and reaction rate during the growth of a single catalyst-polymer particle. The model is based on experimental data and actual plant operation results. At the beginning stage of polymerization, a catalyst macroparticle breaks into thousands of uniformly-distributed primary particles. These microparticles are all identical in radius and uniformly-distributed in the growing macroparticle throughout the whole reaction. Monomers diffuse through polymer blank and react on the microparticles surface to form new polymer. Discussions are concentrated on diffusion effect and it is supposed that only one type of active site is distributed on catalyst surface. The model can account for multiple-active sites quite easily. Some simulation results are given to compare the physical and chemical reasons for broad MWD. The influences of catalysts particle and subparticle size, catalysts activity and monomer diffusion coefficient on polymerization are analyzed.The results show that the degree of polymerization (DP) and polydispersity index Q have strongly antisymmetric distribution under different diffusion coefficient D. D iffusion effects are more prominent with highly active catalyst. When catalyst radius and primary particle radius are small, diffusion resistance is not important. UMGM can be extended to multiple active sites and more complex polymerization kinetics. It lays a foundation for the modeling and optimization of actual industrial reactors.pposedthatonlyonetypeofac

In the paper, the two-dimensional temperature profiles of spherical α -Al 2O 3, cylindrical methanol synthesis catalyst, and ring pellet ethylene oxide synthesis catalyst in packed bed with air flow are obtained by using a wall-cooled fix-bed experimental equipment, in which experimental temperature can be measured in both axial and radial directions at the same time. The radial effective conductivity and wall heat transfer coefficient are calculated by using a two-dimensional psuedo-homogeneous heat transfer model.With reference to different equivalent diameters for ring pellet, the equivalent specific surface diameter is determined by calculating both the inside and outside surfaces of ring pellet. The heat transfer parameters are correlated as a function of Reynolds number Re p.

According to measurements,the specific pore surface area and pore volume of petroleum coke (PC) during combustion were found to: first increase, then decrease and increase again. This indicates that the combustion of PC can be divided into three phases: kinetics control, diffusion control and again kinetics control.The combustion of PC is described in accordance with a fractal rule. The fractal dimension can be compared to the rate of combustion.

The corrosion inhibition by polyacrylic acid for industrial pure iron in HCl solution was studied by using stable state polarization curves and polarization resistance ( R p). The results show that polyacrylic acid resisted and participated in iron’s anodic dissolution process, but it was not effective on irons cathodic process. The adsorption of polyacrylic acid in lower concentrations at the iron / HCl solution interface followed Temkin isotherm equation and its inhibition efficiency was found to be of a geometric blocking effect. However the inhibition efficiency of polyacrylic acid in higher concentrations was attributed to the inhibition effect on the anodic dissolution reaction of iron. The possible model for adsorption of polyacrylic acid at the iron/HCl solution interface was established. The kinetic equation of polyacrylic acid resisting and participating in the anodic dissolution process was deduced. The possible inhibition mechanism was discussed.

The LDF model has been widely used in various adsorption processes for more than forty years. Since Liaw proposed a parabolic profile within a particle, this profile has been widely accepted as the mathematical and physical basis of the LDF model for twenty years. However, when dimensionless time is very small, this classical parabolic concentration profile would yield a negative profile within a particle, which is physically unrealistic. Although the r 5 profile proposed by Li and Yang can also lead to the LDF model and yield less negative profile than the parabolic profile, it inevitably produces the negative profile at very small time yet. In this paper, a new concentration profile, r n(t) profile, corresponding to the LDF model, is proposed. The exponent n(t) is a function of time, and decreases with time. This profile leads to the LDF model, but does not yield the negative concentration profile at any very small time. Furthermore, it has the volume-average adsorbed amount obtained by integrating this profile which exactly equals to that calculated directly from the LDF model mathematically. When the dimensionless time is smaller than 0.04, the parabolic profiles deviate clearly from the exact profiles, and when the dimensionless time is larger than 0.04, the r 5 profiles deviate from the exact profiles. In contrast to these two kinds of profiles, within the whole time domain, the shape of the r n(t) profiles is much similar and close to the shape of the exact profiles within the particle than the parabolic profile and the r 5 profile. Therefore, the r n(t) profile is the best match for the LDF model.

In this paper, the molecular simulation technique is used to study the stabilization effect of trypsin caused by hydrophilization modification. First, the tertiary structure of amine modified trypsin are built by the CVFF force field based on the crystal structure of native trypsin. The Ooi model and the Vila model are used to calculate the solvation energy of native and amine modified trypsin based on their tertiary structures. The computational results show that the solvation energy of trypsin decreases obviously after modification, with the higher degree of modification corresponding to the lower value of solvation energy. After analyzing the relationship between the solvation energy and the thermal stability in detail, it is found that the change of solvation energy can qualitatively describe the thermal stability of native and hydrophilization modified trypsin.

A new hydrogenation method was introduced in an adiabatic fixed-bed reactor with gas and liquid upflow cocurrently. Three reaction regimes, i.e., liquid phase regime, mixed phase regime and gas phase regime were observed in the bed through regulating the operating conditions. Hydrogenation of benzene to cyclohexane over palladium catalyst was used as the model reaction. The effects of hydrogen flow rate, liquid flow rate, feed temperature and pressure on the flow regime were studied. For exothermic reactions, a small increase in reaction temperature can lead to a large increase in reaction rate due to Arrhenius temperature dependence of rate constant .The increased reaction rate results in more heat generation which further increases reaction temperature, this may results in reactor runaway. In this work, we propose that it is possible to obtain effective temperature control by using a fixed-bed reactor with cocurrent upflow of the reagents. The reaction heat evolved is absorbed by evaporation of the liquid phase. The experiments showed that the conversion of benzene in the reactor with this new kind of operation could reach almost 100%, and the risk due to hot spots appearance may also be avoided.

A riser with high density has unique behavior as compared with conventional circulating fluidized bed. With increase of cross-sectional solids fraction, the radial profiles of solids fraction,and particle velocity become significantly non-uniform. The objective of this paper is to develop unique internals that can improve the poor distribution of solids fraction and particle velocity. The experiments are conducted at a high-density riser with 0.186 m ID and 9.0 m in height. FCC particle with particle density 1398 kg·m -3 and average particle size of 54 μm as fluidized material. The apparatus was operated under typical conditions of high-density riser. Two-dimensional LDV and optical fiber density sensor are used to measure the particle velocity and solids concentration in the high-density riser. The radial solids concentration profile in the high-density riser is significantly changed with internals added in the riser. The solids concentration profile downstream the bluffs is much flatter than without internals case. The particle measurement shows that the core-annular structure is destroyed. Transient signal analysis shows that the particle turbulent intensity increases several times near the wall region. The addition of internals reduces the average solids concentration near the internals, while the solids circulating rate changes insignificantly with the addition of internals. The internals can make the radial solids concentration and particle velocity profile uniform downstream the riser, but the length that shows improvement of gas-solids flow in the riser by the internals is about 0.8 m.

The production of ATE(anti-thrombus enzyme) from a kind of Bacillus subtilis immobilized in NaCS-PDMDAAC microcapsules was studied.The influence of mean diameter of microcapsules, concentration of PDMDAAC and the components of culture medium on the production of ATE in the condition of encapsulation culture was studied. In shaking flasks, the maximum enzyme activity in microcapsules was 1850 UK·ml -1 when the mean diameter of microcapsules was 1.60 mm, the concentration of PDMDAAC was 2.0% and the culture medium was LB culture medium(Tryptone)+glucose(0.5%)+phosphate buffer(100 ml).A bubbling culture system was designed. In this system, the maximum enzyme activity in microcapsules was 2050 UK·ml -1 , which was 3.6 times that in the condition of suspension fermentation; the maximum cell density in microcapsules was 4.89×10 9cells·ml -1 , which was 2.7 times that in the condition of suspension fermentation.

Nanosized TiO 2-Al 2O 3 composite particles were prepared by gas-phase oxidation of TiCl 4 and AlCl 3 in an aerosol reactor. XPS, ICP, TEM, and XRD measurement were used to characterize the chemical composition, morphology, size and crystal structure of the particles. The effect of processing parameters on the characteristics of composite particles was studied. The results showed that the enhancement of nitrogen flow rate into the reactor tail benefited particle size control. The TiO 2 size increased with increasing reaction temperature and residence time. The crystal structure of titania and alumina in composite particles was affected by the AlCl 3 and TiCl 4 feed ratio. Aluminum titanate was formed at 1.73 s residence time, 1400 ℃ reaction temperature, and 2.80 AlCl 3/TiCl 4 feed ratio.

A new polymeric membrane material-polyvinylamine (PVAm), which contains amino-groups facilitating the transport of CO 2 in the membrane, has been developed. A composite membrane used for CO 2 separation was made up by covering a PS basis membrane with the polyvinylamine. Sorption of CO 2 on the PVAm-PS composite membrane and the PS basis membrane was measured by using the volumetric method. The results show that the composite membrane has very high CO 2 sorption capacity, and this sorption capacity arises mainly from the PVAm layer. Temperature has much impact on the sorption, the sorption capacity drops sharply when temperature increases. The sorption mechanism is analyzed. It is deduced that there are physical and chemical interaction simultaneously between the composite membrane and CO 2. The membrane has no obvious sorption for CH 4, N 2 and H 2.

Membrane distillation was investigated by using a hollow fiber module, and the permeate flux were monitored as the feed temperature, feed flow rate, feed concentration, cooling temperature, and cooling water flow rate were varied. A mathematical model of the permeate flux was developed and validated on the experimental data. Agreement between experimental and predicted values was obtained. The parameters of hollow fiber module were studied. The diameter, length and thickness of hollow fiber membranes have optimal values in order to get biggest permeate flux and /or production rate, and each optimal value is related with other parameters

The mean and r.m.s velocities of solid-liquid flow system were measured by Particle Dynamic Analyzer in a fully baffled tank agitated by axial impellers.The effect of particle volumetric concentration was investigated as well.The results showed that the velocity profiles for two-phase flow were similar with those of the single-phase flow in the impeller region.The axial velocities for two-phase flow were higher than corresponding velocities of single-phase,and the maximum relative velocity occurred at the blade tip with 0.03 U tip in value.The turbulence levels were in general lower,about 50% reduction,than those of single-phase flow in the impeller region.Tangential velocities of two-phase flow decreased with increasing particle concentration while the axial velocities remained the same.Due to the presence of the particles,the discharge jet width became narrow.

In this paper,the ash fusion characteristics and mineral behavior of individual coal ash and a series of two-component blendsd ashes are studied.The samples are heated progressively from(IT)at 100?℃intervals in reducing atmosphere.Mineral composition and type at each temperature interval are determined by X-ray diffraction (XRD)analysis.For different coal ashes,the main mineral matter at 800?℃is quartz,anhydrite and hematite,calcite and feldspar.With increasing temperature,oxidation,thermal decomposition,transformation and reaction occur between the components.It can be seen that quartz,anhydrite decrease and anorthite,gehlenite increase.At about 1200?℃,all of mineral diminish and a glass phase is formed.Some combinations of mineral in component coal produce low-melting eutectic composition at a high temperature and this is the main reason causing the non-arithmetic average of softening temperature of blends ash.

In this paper, the boiling points of methyldichlorosilane-methyltrichlorosilane-toluene system and of the three binary systems are determined at 101.3 kPa with a new type of magnetic pump-ebulliometer.The VLE data of the three binary systems, respectively,are correlated with the Margules, van Laar, Wilson, and NRTL equations. The equilibrium composition of the vapor phase of three binary systems are calculated from TPX by indirect method. Activity coefficients are calculated after accounting for the nonideality of the vapor phase. The model parameters of liquid activity coefficient are correlated by the least square method. The vapor pressure of the pure components are obtained by using Antoine constants from the literature. The VLE data of ternary system are predicted by the Wilson equation. The calculated boiling points show good agreement with the experimental data.

The histories of differential pressure fluctuations and their Fast Fourier Transform spectrum have close relation with the flow regimes.Unfortunately,each type of flow regime is very difficult or impossible to be distinguished from the other on the basis of the fluctuations or the spectrum.The present paper provides a feasible solution, which the gas-liquid two-phase flow regimes can be recognized automatically and objectively on the basis of the combination of the Counter Propagation Network (CPN) and the FFT spectrum of the differential pressure fluctuations. The CPN takes advantages of simpler algorithm and fast training processes.Furthermore,it does not require a great deal of samples.The recognition possibility is determined by the clustering results of the Kohonen layer in the CPN.With the presented test cases,the possibility can be higher than 90 percent for different liquid phase velocity.