A new concept,compound damp drip for absorbing shock wave in oscillatory tube,is developed in the present paper.The main idea of the concept is that the shock wave absorber must has the two functions,that is,it can not only exhaust the energy of the incident shock wave fully but also transfer the energy out promptly.In the experiment,the compound damp drip is structured with a multi-orifice for intensifying the energy dissipation of the shock wave and an internal cooling system for strengthening the heat transfer.The experimental results show that a strong reflect shock wave,whose strength is 66%of the incident shock wave ,is measured at the position of the relative tube length x/L =0.3 when the oscillatory tube without the compound damp drip.But,after the compound damp drip is amounted at the closed end of the tube,the reflect shock wave is eliminated effectively and the refrigerating efficiency η is increased by 4%～10% in case of the L/d ratio is 140 and the expansion ratio ε is changed from 2.0 to 6.0.What is more ,the refrigerating efficiency in case of L/d =140 and the tube is mounted with the compound damp drip is still higher by 2%～6% than that the tube without damp drip but L/d =300.The above result means that while the damp drip is used,the refrigerating efficiency can be increased and the size of the refrigerator can be decreased significantly.

Axial mixing coefficients in gas phase under nitrogen-water two-phase flow conditions at high pressure were measured in a packed column (0.15m diameter,8.4m high, with a 2.1m packed section) by the technique of pulse injection of hydrogen. The packing was 350Y Mellapak, manufactured by the Tianjin UnivTech Co. Ltd.. Nitrogen and water flowed countercurrently through the column at gas rates from 0.03 to 0.15m·s^-1 ,and liquid rates from 17.0 to 75.0m³·m^-2 ·h^-1 . The operation pressure varied from 0.10 to 1.70MPa.The hydrogen concentration in gas phase was detected continuously by means of thermal conductivity. The one dimensional diffusion model was used for smoothing the experimental response curves with 7 per cent average errors. The experimental data showed that the axial mixing coefficient in gas increased with the increase of the interstitial velocity and the operation pressure. This trend may be due to the increase of the density and the viscosity of the nitrogen under high pressure. Practically no effect of the water loading on the axial mixing coefficient was observed.

A self-cleaning stirred bed reactor with double axes was designed to carry out the study on kinetics of gas phase polymerization of butadiene with heterogeneous rare-earth catalyst, especially for solving the problems of 1,4- cis -polybutadiene particles agglomeration and sticking to the wall of reactor. The effect of diffusion resistance on polymerization rate was investigated.The influence of monomer sorption in microparticle was examined in order to determine the local monomer concentration on the polymer shell surrounding the active sites of the catalyst surface. Flory- Huggins’ sorption isothermal instead of classic Henry’s law was used to characterize the sorption of 1,3-butadiene on 1,4- cis -polybutadiene.Based on the experimental results including the effects of temperature and pressure on polymerization rate,an intrinsic kinetic model was proposed.The simulation result of the model was in good agreement with the experimental data.The model could be applied to similar heterogeneous catalyzed polymerization.

The mathematical model based on Computational Fluid Dynamics (CFD) technique is developed for the direct current arc plasma jet reactor in order to optimize the reactor structure and operation conditions for the direct production of acetylene from coal by thermal plasma technique.In this model, fluid flow, convective heat transfer,and conjugate heat conductivity are considered simultaneously on the basis of rational assumption. It avoids the error caused by estimating the temperature of inner wall of the reactor. Realistic allowance is made for turbulent behavior, temperature- dependence property value,and boundary conditions.The thermodynamic and transport properties of H₂/Ar system, which are usually expressed in the tables of discrete data, are fitted into the expressions that can be easily inserted in the program.Simulations of turbulence is carried out by commonly used standard k-ε two equation turbulence model.The temperature field and velocity field in the plasma jet reactor are calculated by using SIMPLEST algorithm.The conclusion obtained provides guidance for further experiment and technical development.

Current trends toward increased model detail and rigorous optimization of chemical process accelerate the need to solve very large systems.Even with the high performance computers nowadays,there still exists many difficulties for a single computer to solve large-scale chemical process optimization problems.In this paper,parallel computing and algorithms for chemical process optimization problems are reviewed.Details of cluster of workstations,a relatively recen development,are given to highlight its advantages compared with other approaches in parallel computing.As SQP has emerged as the algorithm of choice for solving large-scale chemical process optimization problems,several parallel strategies for SQP are also presented.Finally,a parallel strategy utilizing cluster of workstations is proposed to solve chemical process optimization problems efficiently.Observations indicate that the degree of granularity plays a major role in this approach.It should be carefully schemed to balance the load of communication and the distributed calculation steps.Computing results on a distillation column optimization problem demonstrate the efficiency of this approach.

In this paper,high heat penetration into a moving particulate bed is described mathematically with a comprehensive heat and mass transfer model.The distribution of gas velocity and pressure,the temperature field of gas and solid in the moving particulate bed are examined for different conditions.The results show that thermal penetration into the moving packed-bed particles by fluid flow in porous media is high only in the position near the gas entrance.The thermal penetration thickness tends to increase with the fluid flow velocity and decrease with the particle moving velocity.In the region of thermal penetration,the porosity of solid bed has significant effect on gas field and pressure loss.it is feasible to reduce the gas pressure loss by a larger width/height packed bed in design and operation.The correspondence between thermal infection depth and particle bed height would be helpful to keep high oapacity of reactor and reduce the cost of operation.

The characteristics of 13 bit multi-velocity lattice gas automata model have been analyzed. The statistical method of estimating parameters, such as permeability etc., in lattice gas automata model is discussed. Furthermore, the model has been used for investigating fluid flow through porous media such as coke and some simulating structures. It is shown that the knowledge about fluid flow through porous media can be acquired not only in detail but also from statistics parameters by using lattice gas automata model.It is valid to model fluid flow through porous media whose geometry boundary condition is so complex.

An evaluation and screening device for granular catalyst is designed,and an example of acetoxidation of ethylene in gas phase on hollow cylindrical catalyst with active constituent maldistributed on the outside and inside surface is given. In this example,the reactor is designed as “U”shape,and five thermocouples are set to measure the axial temperature profile of the catalyst bed.The reactor and the preheat pipe are both put into an oil bath kept at constant temperature.Each granular catalyst ( 5mm×1.8mm×5.5mm) is split into eight smaller pieces of the same size,thus the equivalent diameter d s of the smaller pieces is equal to 2.2mm,the inner diameter d t of the reactor is 16mm, dt/ds is equal to 7.3,so that the wall effect is considered to be eliminated.The length of packed bed,including the catalyst and the inert carrier,is 145 times than d s,so the reactor is a plug flow reactor. The global kinetics equation is studied in a CSTR.It is found that the kinetics parameters of split catalyst is same as the full granular catalyst,so the active constituent distribution remaines unchanged with the catalyst split into uniform small pieces. The reaction-heat transfer models are applied to the multiple reactions net of gas phase acetoxidation of ethylene to synthesis of vinyl acetate.The results of model simulation and experimental data indicate that 30mL catalyst bed in 1∶2 dilution ratio(catalyst:inert carrier)is appropriate,it practically achieves isothermal operation inside the bed and presents good comparable results for screening and evaluating hollow cylindrical catalyst with active constituent maldistribution.

In this paper,water-oxalic acid-TOA(octanol) is used as the experimental system,and TOA,octanal as complexing agent,diluent respectively.The extraction mechanism of oxalic acid by TOA and the influence of the concentration of TOA ( S₀) and solute on extraction equilibrium are studied.The structure of complex in organic phase is measured by infrared spectroscopy,and it is obtained that there are two types of complexates in organic phase,1∶1 and 1∶2 (acid∶TOA).The distribution coefficient increases with S₀.Loading of complexing agent shows an increasing tendency with S₀ and the equilibrium concentration of acid in aqueous phase( x ).The saturated loading is achieved at higher x and increases with S₀.The methematical model with two type complexes is proposed based.The model parameters, K₁₁ and K₁₂ are obtained by fitting the experimental data of extraction equilibrium,and K₁₁ is much larger than K₁₂ .

The multi-stage hydropyrolysis (holding near the peak temperature of 500 and 600℃ for 10min,respectively)of Xianfeng lignite was investigated at heating rates of 5℃·min^-1 and 25℃·min^-1 in a 10g fixed-bed reactor.The effects of residence time,heating rate,gas flow and pressure on product yields of hydropyrolysis with different heating methods were studied.Higher yields of tar are obtained in multi-stage HyPy than in normal HyPy.The results showed that the tar yields and overall conversions at high heating rates in multi-stage hydropyrolysis approximated to those at constant slower heating rates;the retention effect is remarkable with increasing heating rate,pressure and hydrogen flow.The experiments under syngas exhibited the potential advantage of multi-stage HyPy in industrial utilization.

The main components and relative contents of tars obtained in multi-stage hydropyrolysis(M-HyPy) of Xianfeng lignite were analyzed by GC-MS and compared with those in traditional single-stage hydropyrolysis (HyPy).The mechanism of formation of light-end products during M-HyPy was discussed.The results indicated that higher concentration and yields of BTX,PCX and naphthalene were found in M-HyPy as compared to HyPy,which is resulted from promoting hydrogenation and inhibiting repolymerization of free radicals due to the retention of hydrogen in M-HyPy.More light oil was obtained through regulating the reaction conditions,such as increasing pressure and gas flow.The tars produced in multi-stage pyrolysis under syngas were also analyzed.

Three kinds of complex oxides and mixed oxide were prepared with different methods, MgO mixed simply with Fe₂O₃,Fe₂O₃ loaded on MgO with impregnation,and MgFeO_x calcined on the MgFe hydrotalcite.The desulfuration rates and the sulfur capacities of the materials were measured. It was found that MgFeO_x showed the best performance and its sulfur capacity exceeded 1.4 g SO₂/g material. The reason for high rate and capacity was analyzed from BET data, XRD and IR spectra. The synergistic action of Mg and Fe dispersed uniformly in complex oxide , in which Fe was the oxidizing center and Mg was the adsorbing center , speeded up the desulfuration rate and increased the sulfur capacity.

By using the finite volume method and the spectral band model, the coupled radiative-conductive heat transfer is numerically simulated in an absorbing, emitting, scattering and non-gray medium.The results for a one-dimensional scattering medium and a two-dimensional, cylindrical medium are compared with the results by the ray tracing method and the discrete transfer method, respectively. It is shown that the finite volume method is precise and suitable for the coupled heat transfer of radiation and conduction. The effects of the spectral band model, refractivity and albedo on the coupled radiative-conductive heat transfer is investigated.The spectral band model is suggested for the non- gray medium and the influence of refractivity on heat transfer should be considered.

On Pt-Rh alloy electrodes, the effect of some operational parameters on the adsorption process of several unsaturated aliphatic acids was respectively examined by fast cathodically potentiodynamic polarization. As the experimental results shown, the adsorption rates of acrylic acid , crotonic acid, and maleic acid, obey Rogynski-Zilidowicz equation always in the middle coverage .Comparatively, the maximal values are determined on the pure Pt-electrode, and as the electrode binary composition is varied successively from the pure Pt to Rh , the adsorption rates for these acids are generally decreased, even by 20～30 times. Among the three unsaturated aliphatic acids, acrylic acid is most advantageously adsorbed on the electrode surfaces. The adsorption activity order is acrylic acid >crotonic acid>maleic acid.

When two liquid phases are mixed, it is important to know the variation of drops distribution for the research of mass transfer. Recently, the method mostly used is to set up a population balance model. But in the model, it is difficult to get the coalescence frequency not only from direct observation but also from mechanism modeling.Therefore, a spray-stirred mixer is set up to obtain instantaneous drops distribution. And the breakage frequency can be ignored when liquid drops is very small.There is only coalescence frequency that can affect drops distribution, which can be obtained from the instantaneous drops distribution. In this paper,the drops self-similarity is tested and drops coalescence frequency can be obtained by the inverse-problem method. Compared with the coalescence frequency deduced from theory, this method can give more exacted drops distribution.

The yttria-stabilized zirconia(YSZ)film was fabricated on the La_0.8Sr_0.2MnO₃(LSM)substrate by electrochemical deposition.The effects of electrochemical deposition conditions on morphological structure of Y(OH)₃ -Zr(OH)₄ film were studied.The optimal conditions for depositing homogeneous and compact hydroxide film were obtained.The experimental results show that the density of the electrophoretic deposition film is increased remarkably if electrochemical deposition is applied to fill in the pores.

Fish oil ethyl esters complexed with aqueous silver nitrate solution were extracted and rectified by supercritical CO₂ to obtain DHA ester and EPA ester with high purity. The effects of some independent variables,such as extraction pressure, temperature gradient of rectifying column and programmed pressure,on rectification were investigated.The results showed that programmed pressure is suitable for purification of EPA and DHA esters. Increase of column temperature gradient from bottom to top is one of the key elements in rectification. Furthermore, higher temperature gradient leads to better separation effect.

Algorithm of the minimum total vapor capacity of batch distillation of ideal binary mixture under total reflux and top accumulation and ideal operation condition is developed.A function f(x _D) [equation(7)]is set up and transformed into g(x _D)[equation(10)]in order to determine that the instantaneous constant region is on the top(or in bottom).For designed separation task,the method for determining the interval of x _D in which the instantaneous constant region is on the top(or in bottom)and the equations for calculating minimum total vapor capacity are derived.

The enantiomeric ratio ( E ) is frequently used to characterize the enantioselectivity in enzyme-catalyzed kinetic resolution. In this paper two methods are evaluated in terms of accuracy, sensitivity towards E and its distribution.For the equation of Chen et al , the probability of r(ee_p)∈[0.5, 1.0], the influence on E of enanatiomeric excess of product ( ee_p), nearly reaches 0.75.The probability of r(ee_p)∈[0.7,1.0] exceeds one half.All r(ee_p) values are higher than 0.6 at conversion ratio ( C ) below 50%. For the equation of Rakels et al , the majority of r(ee_p) exceeds 0.6 when ee s, enantiomeric excess of substrate is lower and ee_p is higher.During the final phase of a reaction when ee_s is large, the changes of ee_s have greater effects on E than that of ee_p,but the probabilities for the above two cases do not exceed 0.5.In addition, there are quite a few situations in which r(ee_p) is equal to 0.4,0.5 and 0.6. This is the most distinguished discrimination of two methods and may also be the primary reason for which the latter is superior to the former.

In the design of IMC controller or other robust controller for robust performance in process control application, one of the necessary conditions is model (or process) uncertainty bound. The method of calculating model (or process) uncertainty bound for the first order lag process with dead time (FOPDT) in the robust controller design is reported in literatures. Up to the now, however, no any analytical method of calculating model (or process) uncertainty bound can be used in the second order lag process with dead time (SOPDT). Therefore, the design of the IMC controller for robust performance used to SOPDT also can not be simply achieved.By using first order Pade approximation for the dead time,an analytical method of calculating model (or process) uncertainty bound for SOPDT in the robust controller design is given for the first time.By using this bound, IMC controller design for robust performance can be made satisfactorily.