Propylene oxide (PO) is an important organic chemical intermediate. During the synthesis of PO by direct catalytic oxidation, both the selection of catalyst support and the preparation method of catalyst play an important role on the activity of catalyst in addition to the active species on catalyst.In this paper the research progress of the factors which influence catalyst performance is summarized and discussed to provide reference for future work.

Based on the postulated 2D average molecular unit structures proposed by Zhao et al, 3D conformations for the end-cuts of Athabasca bitumen pitch in Canada were created using polymethylene bridges with different lengths by the Computer Aided Molecular Design (CAMD) method. Molecular Mechanics (MM) and Molecular Dynamics (MD) computations were carried out on these conformations to determine the lowest energy structures and hence the most stable conformations.The 3D conformations and the total energy of the target molecules were intimately related. It was found that the equivalent conformations in three dimensions were quite varied even though the two-dimensional structure remained exactly the same.This meaned that simple 2D structures of macromolecules could not adequately represent their structural, physical and chemical properties. The most likely polymethylene bridge lengths within the pitch end-cut molecules were estimated from the CAMD results; a value in the range of C4 to C6 was most likely.The probability of C1 and C2 bridges was less because their total energies were comparatively high.

The renormalization group theory is applied to calculating the critical behavior of water in which density fluctuation is taken into account.The Stockmayer potential is adopted to express the interactions between water molecules. The parameters regressed from critical temperature are used to predict the behavior of water at supercritical and near-critical temperatures. The calculated pressures are compared with the experiment data. The results show that the RG theory is suitable to predict the thermodynamic properties of water in critical region.

Hydrate formation conditions of twelve synthetic hydrogen + hydrocarbon gas mixtures (H₂ + CH₄, H₂ + C₃H₈, H₂ + CH₄ + C₃H₈, H₂ + CH₄ + C₂H₆ + C₃H₈) were measured in a sapphire cell using the “pressure search” method. The experimental temperature range was 274―280 K, and the pressure range was 0.65―7.0 MPa. The hydrogen content in the gas mixtures varied from 22% to 92%（mol）.By using PR equation of state and suitable mixing rule, the Chen-Guo’s hydrate model was extended to calculate the hydrate formation conditions of the hydrogen-containing systems. Satisfactory agreement between experimental data and calculated results were achieved.

It has long been recognized that liquid flow pattern especially liquid circulation, or reverse flow, is of great importance in determining tray efficiency.Research work concerning tray efficiency calculation is reviewed and a mathematical model which combines computational fluid dynamic model with mass transfer equation to predict the details of the mass transfer process on a distillation tray is proposed. By solving the proposed model, the velocity distribution of liquid phase and concentration profiles of vapor and liquid phases can be calculated simultaneously. Complete mixing and partial mixing of vapor phase is investigated in simulating the details of mass transfer process. The result reveals that the tray efficiency calculated in the assumption of complete mixing of vapor phase is greater than the real value. The computed results verify the qualitative assumption that the vapor leaving the liquid circulation region has very little change in concentration. The quantitative results of tray efficiency vs. the size of circulation region is given.

On the basis of experimental results, the flow in the pulse-jet space and inside ceramic candle filter is regarded as a two-dimensional, unsteady, compressible and axisymmetric flow. The flow across the ceramic tube wall is considered as unsteady Darcy flow. The k-ε two-equation turbulence model and energy equations are used to account for the turbulence and heat-transfer effects. The flow procedure can be used to calculate the transient flow characteristics of rigid ceramic candle filter during the whole pulse cleaning process. The numerical predictions of flow field are in good agreement with the experimental measurements.The effects of pulse gas temperature and filter operating temperature on flow field are numerically investigated. The numerical calculations provide the theoretical basis for optimum design of pulse cleaning system and understanding of the filtration mechanism inside ceramic filter.

The transient hot-wire method is used to measure the thermal conductivities of nanofluids.The experimental results show that nanofluids have remarkably higher thermal conductivities than those of conventional pure fluids.The thermal conductivities of nanofluids are not only influenced by the volume fraction of nanoparticles, but also by other factors such as properties and dimensions of nanoparticles.By analyzing the experimental results, a correlation of thermal conductivity of nanofluid is presented.

In this paper,the prediction of void fraction and pressure drop for upward gas-liquid annular flow in a vertical annulus is studied.According to the idea of Kelessidis(1989)for the flow pattern transition from churn to annular flow and the integral analysis method of Wallis(1969)for the velocity profile of single-phase flow in an annulus,a new model for prediction of void fraction and pressure drop is proposed based on considering the structural feature of the concentric annulus and the flow pattern characteristics.The present model is compared with existing models and the experimental data from this paper and the literature.It is in better agreement with experimental data than existing models.

The catalytic multi-stage hydropyrolysis (HyPy) of Xundian lignite was investigated by using thermogravimetric technique and fixed bed reactor.The preparation methods for MoS₂ catalyst, including magnetic stirring and ultrasonic treatment, were also studied. The results showed that the total conversion increased due to the increase in formation rate of free radicals and its saturation reaction with catalyst added. When the amount of MoS₂ was 0.2%, the conversion after retention at 350 ℃ was sharply increased to 50% compared to that of 26% without catalyst.The effects of catalyst loading on the conversion at a low temperature peak and a high temperature peak during multi-stage hydropyrolysis (MHyPy) were different. When the catalyst was prepared by using ultrasonic treatment, the conversion in both HyPy and MHyPy was always higher than that with catalyst prepared by magnetic stirring and such effect was even more remarkable at higher temperatures. During MHyPy of coal utilization of catalyst and ultrasonic preparation could notably improve conversion and oil yield. Catalytic MHyPy changeed the product distribution and greatly increased the concentration of light aromatics in the tar, during which benzenes, phenols and naphthalenes increased by 42%, 37.8% and 115.4% respectively as compared with HyPy.

In this paper, the effects of hydrogen on CO coupling reaction to diethyl oxalate at different hydrogen concentrations, reaction temperatures and residence times are studied. The results show that after introduction of hydrogen, CO conversion, selectivity and STY of diethyl oxalate all decrease with the increase of hydrogen concentration and reaction temperature. The deactivation kinetics of CO coupling reaction after introduction of hydrogen is obtained as follows:-da/dt=k_dc^0.65_H2. According to this kinetic model the deactivation mechanism of the catalyst is further discussed. It is found that the co-adsorption of hydrogen and CO on the same active site of the catalyst occurrs.Adsorption of hydrogen will decrease the adsorption of CO on the catalyst and then decrease the formation rate of diethyl oxalate, CO conversion and space yield of diethyl oxalate.

The solubility of catalytic membrane of PVA-Zr(Ⅳ) was investigated and that the catalytic layer was found to swell in nearly two hours. The composition of the bulk liquid mixture was varied during the swelling and was different from that of the catalytic layer when the swelling equilibrium state was reached.Furthermore, the reaction rate constants of reaction kinetics equations were obtained for the esterification of acetic acid with n-butanol catalyzed by PVA-Zr（Ⅳ）catalytic membrane. The esterification was taken as a model reaction to study the permeation properties of the catalytic membrane with comparison of the membrane without a catalytic layer. The permeation flux for the catalytic membrane was less than that for the non-catalytic layer membrane in the first reaction stage during swelling, and such comparision was reversed around four hours later when swelling equilibrium was reached.

The circulating moving bed is an innovative coupled reactor for synthesizing linear alkylbenzenes, and it only requires relatively shorter lifespan of catalyst than that of traditional fixed bed reactors. In the circulating moving bed reactor, the reaction process and the regeneration process are coupled to realize a continuous operation. As a result, the equipment investment and the operating costs can be significantly reduced. In this model, the effect of catalyst deactivation on the reaction is simulated by using the infinitesimal balance equations.The results of step changes between steady states and unsteady states are also calculated with the model.

Based on the concept of RDF(Refused Derived Fuel) pyrolysis by partial combustion and subsequent gas combustion, a reactor with two reaction zone (a spouting-moving bed pyrolyzer and a gas combustor) was developed, which was proposed for thermal disposal of solid wastes especially RDF. The RDF produced in the authors’ laboratory was used to evaluate the performance of the reactor. RDF was continuously fed to the spouting-moving bed pyrolyzer in which RDF was partially burned to supply heat for pyrolysis of RDF at a lower temperature, then the pyrolysis product gas was burned with secondary air at a higher temperature in the upper combustor. The flow-rate effects of spouting air, auxiliary air and secondary air on the profiles of temperature and pyrolysis gas composition were measured.

Supercritical water oxidation(SCWO) of ethanol was performed in an isothermal, plug-flow reactor at temperatures from 475 to 550℃, pressures from 22 to 30 MPa, reactor residence times from 0.6 to 63.7s, and oxygen/ethanol molar feed ratios from 4.56 to 9.09.The experimental results showed that carbon monoxide and carbon dioxide were the major intermediate and the final product respectively.The ethanol conversion increased with increasing residence time and temperature and did not obviously change with varying pressure or oxygen concentration.The global kinetics for ethanol disappearance was described by a rate law that was first order in ethanol and zero order in oxygen, and the deviation between calculated and experimental results was approximately within 10%.Furthermore, SCWO processes of ethanol with different oxidant——oxygen and hydrogen peroxide were studied and compared.The same behaviors were observed under supercritical conditions, while under subcritical condition the oxidative rate with hydrogen peroxide was faster than that with oxygen.Based on the observed phenomena, a new viewpoint on SCWO reaction mechanism was proposed that under supercritical condition with oxidant of either hydrogen peroxide or oxygen, a very fast equilibrium distribution between these oxidants would be reached through a series of free radical reaction regardless of their initial concentrations, and the oxidation was proceeded under the condition of equilibrium distribution of oxidants.

The FGD process of mixture of lime and Fe₂O₃ is analyzed by using TGA in this paper.It is shown that Fe₂O₃ can’t react with SO₂ from 200℃ to 700℃.The desulfurization efficiency of lime is improved with temperature rising.SO₂ can be captured by lime at 600℃ or 700℃. But there is almost no desulfurization reaction taking place with lime when temperature is below 500 ℃. The behavior of lime in desulfurization reaction does not change with added Fe₂O₃. But the conversion rate of CaO is greatly improved:the more Fe₂O₃, the higher the conversion rate.Fe₂O₃ acts as an activator more than a catalyst in the desulfurization reaction with lime.Fe₂O₃ acts as the “activation center”around which CaO particles are sulfurized.The new dispersal formation mode of product differs from the compact layer that used to be. And the pore structure of product layer on the surface of lime particles is optimized, which makes SO₂ penetrate into core parts of lime more easily. As a result, the desulfurization reaction is developed deeper into the core parts of absorbent.

The SO₂-sensitive organic silicate film was formed on the interdigital capacitor based on silicon dioxide by means of sol-gel process and spin-on technique.Measurements of interdigital capacitance were performed at room temperature for frequencies 0.1 kHz,1 kHz and 10 kHz. It was shown that there was a linear relationship between the capacitance and the concentration of sulfur dioxide gas. The influences of the measurement frequency and the film thickness of silicate on the sensitivity of the sensor to SO₂ gas were discussed.Organically modified N,N-diethylaminopropyltrimethoxysilane showed a much higher sensitivity.

The potentiality of the conversion of 7-aminodeacetoxicephalosporanic acid(7-ADCA) to cephalexin using penicillin G acylase (PGA) (penicillin amidohydrolase, EC3.5.1.11) was studied in aqueous two-phase systems (ATPS).In a system consisting of 20%(mass) PEG 400 and 12%(mass) magnesium sulfate, the partition coefficient of PGA was less than 0.01, PGA almost completely partitioned into the magnesium sulfate-rich bottom phase. Meanwhile, the partition coefficient of cephalexin was 6.7, the partition coefficients of phenylglycine methyl ester (PGME) and 7-ADCA were 1.5 and 1.2, respectively. Then the stability of PGA in 20%(mass) PEG 400/15% (mass) magnesium sulfate ATPS was investigated and the results showed that PGA was suitable for the enzymatic synthesis of cephalexin in ATPS. When pure enzyme was used for bioconversion, a high yield of cephalexin (60%) was achieved form 75 mmol·L^-1 7-ADCA and 75 mmol·L^-1 PGME in the developed ATPS.

Chars prepared from coals treated with concentrated acids of HF and HCl to remove mineral matter were combusted under programmed temperature and isothermal conditions.The results showed that mineral matter in coal char played an important role in the conversion of char-N to NO. Alkali metals Na and K shifted the production of NO from char-N to a lower temperatures and inhibited NO emission. However, Ca and Fe increased the conversion of char-N to NO at a lower temperatures but decreased the release of NO at a higher temperatures, which implied the importance of catalytic condition and the complicated mechanism of NO formation and reduction. It was demonstrated that inert mineral matter in the char enhanced the conversion of char-N to NO. The net effect of mineral matter on NO emission level was combined effect of many components in mineral matter. It was also found that char-N conversion to NO increased with coal rank and NO emission increased with increasing temperature to maximum then decreased at a high temperature. The effect of mineral matter on NO emission depended on its relative catalytic activity in the oxidation of char-N to NO and reduction of NO by char.

Inner pore structure of coal char particle was measured by N₂ adsorption-desorption method.It was shown that there was a relationship between combusted ratio and some important parameters of pore structure. Using fractal theory the surface characteristics of inner pore were quantitatively shown by fractal dimensions. Fractal BET and Freundlich equations were used to calculate fractal dimensions of pore surface and particle bulk.Fractal dimensions were found to be related to char combusted ratio. Fractal dimensions of pore surface and particle bulk of Huainan coal chars changed in different trends.

A space design for the molecule of hydrocarbon based on the traditional group division method is developed, and a group vector space method (GVSM) for estimating critical property of hydrocarbon is proposed by using the module index of the group vector to characterize the group position in the molecule. Expressions for estimating critical properties T_c,p_c and V_c of hydrocarbons are proposed, with the numerical values of relative group parameters presented. The average percentage deviations of T_c,p_c and V_c estimation are 0.62, 2.3 and 1.6 respectively.

Quench chamber is the most important component in the coal gasifier,and is easy to break.In order to find the pattern of turbulent flow and heat transfer of synthetic gas in the Vertical downward pipe,a numerical model based on analyzing the flow and heat transfer features of the vertical pipe in quench chamber is first presented.The variations of temperature，velocity of synthetic gas with the change in length and radius of the vertical pipe and the velocity of the gas are obtained，and the effect of radiation is found. The pattern of turbulent flow and heat transfer of synthetic gas in the vertical pipe is further revealed.

Local slip velocity is an important factor in mass,momentum and heat transfer of riser reactors.Based on the EMMS model, the qualitative and quantitative analysis is made for local slip velocity and its components (the slip velocity in the dense phase (cluster), the slip velocity in the dilute phase and the slip velocity between dense phase and dilute phase).It is found that the slip velocity between dense phase and dilute phase makes the most contribution to the local slip velocity and clusters lead to the high local slip velocity, from which the correlation of local slip velocity with local voidage is derived.Using this correlation, the local gas-solids slip velocities in gas-solids up-risers are predicted.Calculation results are well consistent with experimental data. Furthermore, the effects of operating conditions on local slip velocities are discussed. It is concluded that local slip velocity increases with the increase of solids circulating rate and decreases with the increase of superficial gas velocity.

The pyrolysis reaction of acrylonitrile(AN)/N-vinylpyrrolidone(N-VP) copolymer in air was studied with DSC. The apparent activation energy of pyrolysis reaction of copolymer was calculated by the Kissinger method. The effect of different copolymerization conditions on the apparent activation energy of copolymer was discussed. It was found that with an increase of DMSO concentration in mixture solvent，the degradation apparent activation energy rose rapidly. When the weight ratio of N-VP/AN was less than 5/95, the apparent activation energy of degradation reduced quickly with the comononer N-VP concentration rising, and when the ratio was more than 5/95, the apparent activation energy became almost constant. When the copolymerization temperature rose, the apparent activation energy also increased.

An agent-oriented modeling approach is presented for process systems. A process system consists of two parts: agents and objects. Based on modeling objects and agents, integration of process operation systems is made in terms of three strategies.How to accomplish the three strategies is illustrated and an integrated framework is presented.

For high viscosity bulk-copolymerization of octamethylcyclotetrasiloxane and amino-silicone monomer, a multisyphon flow physical model was established.Based on the free volume and chemical reaction kinetic theories, a new computational model was developed to simulate the multisyphon flow model. As to the new model, the united influence of reaction and diffusion was reviewed and analyzed. The new model was used to simulate bulk- copolymerization of octamethylcyclotetrasiloxane and amino-silicone monomer and agreed well with the results.