Dispersed multiphase flows,including gas-particle(gas-solid),gas-spray,liquid-particle(liquid-solid),liquid-bubble,and bubble-liquid-particle flows,are widely encountered in power,chemical and metallurgical,aeronautical and astronautical,transportation,hydraulic and nuclear engineering. In this paper,advances and research needs in fundamental studies of dispersed multiphase flows,including the particle/droplet/bubble dynamics,particle-particle,droplet-droplet and bubble-bubble interactions,gas-particle and bubble-liquid turbulence interactions,particle-wall interaction,numerical simulation of dispersed multiphase flows,including Reynolds-averaged modeling(RANS modeling),large-eddy simulation(LES) and direct numerical simulation(DNS) are reviewed. The research results obtained by the present author are also included in this review.

The effect of a novel active nucleating agent(TBC8-eb) on the isothermal crystallization of poly(L-lactic acid) (PLLA) was studied by differential scanning calorimetry(DSC) and Fourier transform infrared spectroscopy(FTIR). The analysis on kinetics demonstrates that TBC8-eb can not only accelerate the crystallization rate but also transform most of the original spherulite crystals of PLLA into sheaf-like crystals. Furthermore,the free energy of folding(σ_e) of PLLA and PLLA with TBC8-eb is 0.15 and 0.06 J·m^-2,respectively,which suggests that the addition of TBC8-eb favors the regular folding of molecule chains in the crystallization of PLLA,improv-ing its crystallization rate. The FTIR results show that TBC8-eb can accelerate the conformational ordering of PLLA in the isothermal crystallization. The conformational ordering of PLLA nucleated with TBC8-eb begins with the interchain interaction of —CH₃,and then a short helix emerges where a couple of —CH₃ groups interact.

Biodegradation parameters and kinetic characteristics for pre-treating waste strains of Klebsiella pneumoniae were studied in laboratory scale with an insulated reactor by an innovative technique,autothermal thermophilic aerobic digestion(ATAD). Based on an Arrhenius-type equation,an empirical model was developed to correlate the removal of total suspended solid(TSS) with the initial TSS concentration,influent reaction temperature,aeration rate and stirring rate. The reaction temperatures of the ATAD system could be raised from the ambient temperatures of 25℃ to a maximum temperature of 65℃. The exponentials for the initial TSS concentration,aeration rate and stirring rate were 1.579,-0.8175 and -0.6549,respectively,and the apparent activation energy was 6.8774 kJ·mol^-1. The correlation coefficient for the pre-exponential factor was 0.9223. The TSS removal efficiency predicted by the model was validated with an actual test,showing a maximum relative deviation of 10.79%. The new model has a good practicability.

Molybdenum disulfide nanoflakes were synthesized by a simple hydrothermal process using sodium molybdate and thiourea as reactants at a relatively low temperature. X-ray diffraction(XRD) and transmission elec-tron microscopy(TEM) indicate that the samples have the structure of 2H-MoS₂ and the morphology of nanoflakes with the average thickness around 5-10 nm. The results of electrochemical properties indicate that the morphology and size of MoS₂ particles have effects on their capacity when they are used as the anode for lithium ion battery. The as-prepared MoS₂ samples have high reversible discharge capacity up to 994.6 mA·h·g^-1 for the MoS₂-1 elec-trode and 930.1 mA·h·g^-1 for the MoS₂-2 electrode and show excellent cycling performances. The MoS₂-1 electrode has a better cycling stability than the MoS₂-2 electrode due to their difference in the uniformity of the samples.

In this paper we address the topic of energy and water optimization in the production of bioethanol from corn and switchgrass. We show that in order for these manufacturing processes to be attractive,there is a need to go beyond traditional heat integration and water recycling techniques. Thus,we propose a strategy based on mathematical programming techniques to model and optimize the structure of the processes,and perform heat integration including the use of multi-effect distillation columns and integrated water networks to show that the energy efficiency and water consumption in bioethanol plants can be significantly improved. Specifically,under some circumstances energy can even be produced and the water consumption can be reduced below the values required for the production of gasoline.

The rising behavior of single bubbles has been investigated in six systems with different viscosity and Morton number(Mo) from 3.21×10^-11 to 163. Bubbles with maximum equivalent diameter of up to 16 mm were investigated. The bubble Reynolds number(Re) ranged from 0.02 to 1200 covering 3 regimes in which two functions are obtained relating the drag coefficient,C_D,with Re and Mo. It has been found that in the high Reynolds number regime the drag coefficient increases until the Reynolds number of about 1200. The classic expression of Jamialahmadi(1994) is improved and extended to high viscosity liquids. A new relationship for the aspect ratio of deformed bubbles in terms of Re,the E鰐v鰏 number and Mo,applicable to a wide range of system properties,especially in high viscosity liquids,is also suggested.

Flow behaviors of four kinds of granular particles(i.e. sphere,ellipsoid,hexahedron and binary mixture of sphere and hexahedron) in rectangular hoppers were experimentally studied. The effects of granular shape and hopper structure on flow pattern,discharge fraction,mean particle residence time and tracer concentration distribution were tested based on the visual observation and particle tracer technique. The results show that particle shape affects significantly the flow pattern. The flow patterns of sphere,ellipsoid and binary mixture are all parabolic shape,and the flow pattern shows no significant difference with the change of wedge angle. The flowing zone becomes more sharp-angled with the increasing outlet size. The flow pattern of hexahedron is featured with straight lines. The discharge rates are in increasing order from hexahedron,sphere,binary mixture to ellipsoid. The discharge rate also increases with the wedge angle and outlet size. The mean particle residence time becomes shorter when the outlet size increases. The difference of mean particle residence time between the maximum and minimum values decreases as the wedge angle increases. The residence time of hexahedron is the shortest. The tracer concentration distribution of hexahedron at any height is more uniform than that of binary mixture. The tracer concentra-tion of sphere in the middle is lower than that near the wall,and the contrary tendency is found for ellipsoid particles.

The pressure drop of gas-liquid two-phase flow in microchannel is of fundamental importance in heat and mass transfer processes. In this work,the pressure drop of gas-liquid two-phase flow in horizontal rectangular cross-section microchannels was measured by a pressure differential transducer system. Water,ethanol and n-propanol were used as liquid phase to study the effects of capillary number on pressure drop;air was used as the gas phase. Four microchannels with various dimensions of 100 μm×200 μm,100 μm×400 μm,100 μm×800 μm and 100 μm×2000 μm(depth×width) were used for determining the influence of configuration on the pressure drop. Experimental results showed that in micro-scale,the capillary number also affected the pressure drop remarkably,and in spite of only one-fold difference in aspect ratio,the variation of pressure drop reached up to near three times under the same experimental conditions. Taking the effects of aspect ratio and surface tension into account,a modified correlation for Chisholm parameter C in the Chisholm model was proposed for predicting the frictional multiplier Φ₁²,and the predicted values by the proposed correlation showed a satisfactory agreement with experimental data.

The feasibility of oxidation leaching process of nickel from nickel sulfide ore and the form of different components in the lixivium has been studied at first. The method of leaching nickel sulfide concentration directly by oxidants with existence of ultrasonic has been advanced. The process of leaching nickel from nickel sulfide concentration by using the system of persulfate and silver has been determined. The influence of different factors on the leaching rates of nickel,such as with and without ultrasonic,the concentration of Na₂S₂O₈,liquid-solid ratio and the concentration of AgNO₃ have been explored. The results show that:(1) in the oxidative leaching system,nickel can be leached completely as Ni²⁺ or NiSO₄(aq.) from nickel sulfide concentration in theory;(2) the nicopyrite can not exist steadily in the persulfate acid leaching system,but Ni2+can. Meanwhile,sulfur may be existed steadily in the leaching process;(3) nicopyrite with much lower electrostatic potential may be leached earlier than chalcopyrite and sideropyrite;and(4) the overall reaction rate of the leaching process can be enhanced with ultrasonic radiation,but it does not change the mechanism of leaching. The more oxidant concentration or higher liquid-solid ratio is,the higher leaching percentage of nickel. The leaching percentage of nickel can be increased significantly by adding a small amount of AgNO₃ during the leaching processes. Under the same conditions,the higher concentration of AgNO₃ is,the higher leaching yields of nickel will be obtained.

Though they look very different,UOP SimulFlowTM,Koch-Glitsch Ultra-FracTM,Jaeger CoFloTM and Shell ConSepTM trays fall into the same category of trays using inertial separation technology. However,flooding mechanisms and the trends of entrainment and efficiency are different due to their different working principles. This paper provides a detailed analysis of these trays using available information from literature and U.S. Patents. Efforts are also made to interpret the observations reported. In terms of tray efficiency,it is found that SimulFlow,UltraFrac and CoFlo trays are typical point efficiency devices due to a completely mixed liquid pool on the tray deck,while ConSep trays can take advantage of liquid concentration gradient on the tray deck,which makes this tray attractive among all ultra high capacity trays.

An ionic liquid system of [Bmim]X/[Bmim]OH(X=Cl,BF₄,and PF₆,) was developed for the hydroly-sis of ethylene carbonate to ethylene glycol. The important parameters,such as the variety of ionic liquids,molar ratio of [Bmim]X to [Bmim]OH,amount of ionic liquid,molar ratio of water to ethylene carbonate,reaction temperature,pressure and reaction time,were investigated systematically. Excellent yield(>93%) and high selectivity(99.5%) of ethylene glycol were achieved. Under the optimum reaction conditions,the ionic liquid system could be reused at least five times and the selectivity of ethylene glycol remained higher than 99.5%.

SAPO-34 zeolite is considered to be an effective catalyst for methanol or dimethyl ether conversion to olefins. In this study,we developed the In situ synthesis technology to prepare SAPO-34 zeolite in kaolin microspheres as a catalyst for fluidized methanol or dimethyl ether to olefins process. The silicoaluminophosphate zeolite was first time reported to be synthesized in kaolin microspheres. The SAPO-34 content of synthesized catalyst was about 22% as measured by three different quantitative methods(micropore area,X-ray fluorescence and energy dispersive spectroscopy element analysis). Most of the SAPO-34 zeolites were in nanoscale size and distributed uniformly inside the spheres. The catalytic performance was evaluated in fixed bed and fluidized bed reactors. Compared with the conventional spray-dry catalyst,SAPO/kaolin catalyst showed superior catalytic activities,better olefin selectivities(up to 94%,exclusive coke),and very good hydrothermal stability. The In situ synthesis of SAPO-34 in kaolin microspheres is a facile and economically feasible way to prepare more effective catalyst for fluidized MTO/DTO(methanol to olefins/dimethyl ether to olefins) process.

A 10 kW-scale natural gas fueled proton exchange membrane fuel cell(PEMFC) distributed power plant is presented in this paper,which is designed for cogeneration of power and heat. With homemade catalysts for CO removal in a two-stage methanation process and integrated reactor in the fuel processing system,the reformed fuel with CO molar fraction less than 10^-5 is obtained for the fuel cell stack. Based on Matlab/Simulink/Stateflow and xPC Target platform,a rapid control prototype(RCP) is developed for real-time condition management,signal tracking and parameter tuning,data storing,and man-machine interaction. In a typical running with 4.3 kW stack power,the hydrogen production efficiency,gross power generation efficiency and heat recovery efficiency approach to 76%,41% and 50%,respectively. The peak stack power reaches 7.3 kW. Though there is still considerable distance to long-term operation at 10 kW-scale net power generation,it is a milestone for the PEMFC-based stationary application in China.

The effect of two dissolved inorganic salts,cadmium chloride CdCl₂ and ammonium chloride NH₄Cl,on the excess enthalpy of mixing(H^E) of the binary system methanol + benzene measured at 303.15 K using an isothermal displacement calorimeter with vapor space is investigated in the present work. Compared to the salt-free system,a decreasing trend in the endothermicity of H^E values is significant with the addition of CdCl₂ salt but the decrease in the H^E values is insignificantly smaller with the addition of NH₄Cl salt. The experimental values of the enthalpy of mixing are fitted into a Redlich-Kister equation and the deviations in the values and the parameters are reported. The importance of the solute-solvent interactions and the solvent-solvent interactions are demonstrated from the increasing excess enthalpy of mixing values in the positive direction with the increase of salt concentration.

A new dynamic ebulliometer is used to determine vapor-liquid equilibrium(VLE) data experimentally. In the equipment,both phases are recirculated. Its operation is a consequence of the Cotrell pump effect produced when the mixture is heated in a double-walled inverted vessel. The reliability of the apparatus is tested with the mixtures studied previously by various authors. VLE data for the binary systems of methyl acetate + methanol and the methyl acetate + ethanol at 0.5 MPa are determined. The experimental data are confirmed with the point-to-point test of van Ness,applying the Fortran program of Frendslund et al. In addition,the experimental results are compared with the UNIFAC(including different versions) and ASOG prediction models.

Ionic liquid 1-methyl-3-(3-sulfopropyl)-imidazolium hydrogen sulfate([C₃SO₃HMIM][HSO₄]) was synthesized and characterized by infrared spectroscopy(IR),nuclear magnetic resonance(¹H and ¹³C NMR) and ultraviolet-visible(UV-Vis) spectra. Its thermal stability was also examined by thermogravimetric analysis(TGA) and a differential scanning calorimeter(DSC). The mole fraction solubilities of [C₃SO₃HMIM][HSO₄]) in 12 selected solvents(n-pentane,n-hexane,n-heptane,benzene,toluene,ethylbenzene,acetone,2-butanone,3-methyl-2-butanone,tetrahydrofuran,ethyl acetate and dichloromethane) in the temperature range from 289.15 to 363.15 K were measured using a static analytical method and correlated with an empirical equation.

In general,productions of natural pigment in submerged microorganism culture were much less than that in solid-state fermentation,because the solid-state culture can provide a support carrier for the mycelium. To improve natural pigment production,the cultivation of Monascus purpureus in submerged encapsulated cell was investigated. Monascus purpureus immobilized in polyelectrolyte complex(PEC) microcapsules,which were prepared by sodium cellulose sulphate(NaCS) and poly-dimethyl-diallyl-ammonium chloride(PDMDAAC),was a good substitute for submerged cell culture because it mimicked the solid-state environment. The repeated-batch process with encapsulated cells was studied in flasks and a bubble column. The results indicated that the bubble column was more suitable for the encapsulation culture than the shaking flasks because of its good mass transfer performance and minor shear stress on cells. Owing to the protection of the microcapsule’s membrane,Monascus purpureus in microcapsules increased approximately three times over that in free cell culture with negligible cell leakage to the medium. The pigment production in the bubble column finally reached 3.82(OD₅₀₀),which was two times higher than in free cell culture. In addition,the duration of each batch was shortened to 15% of that in free cell culture.

Bio-oil is a new liquid fuel produced by fast pyrolysis,which is a promising technology to convert biomass into liquid. Pyrolytic lignin extracted from bio-oil,a fine powder,contributes to the instability of bio-oil. The paper presents the structural features of three kinds of pyrolytic lignin extracted from biooil with different methods(WIF,HMM,and LMM). The pyrolytic lignin samples are characterized by Fourier transform infrared spectrometer(FTIR) and X-ray photoelectron spectroscopy(XPS). FTIR data indicate that the three pyrolytic lignin samples have similar functional groups,while the absorption intensity is different,and show characteristic vibrations of typical lignocellulosic material groups O—H(3340-3380 cm^-1),C—H(2912-2929 cm^-1) and C=O(1652-1725 cm^-1). Comparison in the region(3340-3380 cm^-1) indicates that WIF has more O—H stretch groups than HMM and LMM. The carbon spectra are fitted to four peaks:C1,C—C or C—H,BE 283.5 eV;C2,C—OR or C—OH,BE 284.5-285.8 eV;C3,C=O or HO—C—OR,BE 286.10-287.10 eV;C4,O—C=O,BE 287.5-287.7 eV. The absence of C1,C—C or C—H indicates the dominant polymerization structure of aromatic carbon in pyrolytic lignin samples. For HMM and WIF,C2a and C2b can not be separated,so there is no free hydroxyl group in the samples. The oxygen peaks are also fitted to four peaks:O1,—OH,BE=530.3 eV;O2,RC=O,BE=531.45-531.72 eV;O3,O—C=O,BE=532.73-533.74 eV;O4,—H2O,BE 535 eV. The absence of O1 and O₄ indicates that little hydroxyl groups and adsorbed water are present in the samples.

Tertiary amine cationic polyacrylamide with high cationization degree was used as a new cationic agent to pretreat cotton with dip-pad-bake method. The obtained cationic cotton was dyed with reactive dyes in the absence of electrolyte. The effects of the characteristics of the cationic agent and the pretreatment conditions on dyeability of reactive dye were investigated. The results showed that the fixation and K/S values of the reactive dyes on the cationic cotton were improved compared with those on the untreated one in the presence of salt. Tests on fastness properties of the dyed cotton and fabric quality of the pretreated cotton were carried out and the results showed that wash and rub fastness of the salt-free dyeing were both satisfactory. And anti-crease property,tensile and tear strength,and handling of the cationic cotton were also good compared with that of the untreated one.

Chiral aromatic alcohols are the key chiral building block for many important enantiopure pharmaceuticals. In this work,we studied asymmetric reduction of prochiral aromatic ketone to produce the corresponding chiral alcohol using vegetables as the biocatalyst. Acetophenone was chosen as the model substrate. The results indicate that acetophenone can be reduced to the corresponding chiral alcohols with high enantioselectivity by the chosen vegetables,i.e. apple(Malus pumila),carrot(Daucus carota),cucumber(Cucumis sativus),onion(Allium cepa),potato(Soanum tuberosum),radish(Raphanus sativus),and sweet potato(Ipomoea batatas). In the reaction,R-1-phenylethanol is produced with apple,sweet potato and potato as the catalyst,while S-1-phenylethanol is the product with the other vegetables as the catalyst. In term of the enantioselectivity and reaction yield,carrot(D. carota) is the best catalyst for this reaction. Furthermore,the reaction characteristics were studied in detail using carrot(D. carota) as the biocatalyst. The effects of various factors on the reaction were investigated and the optimal reaction conditions were determined. Under the optimal reaction conditions(reaction time 50 h,substrate concentration 20 mmol·L^-1,reaction temperature 35℃ and pH 7),95% of e.e.(to S-1-phenylethanol) and 85% chemical yield can be obtained. This work extends the biocatalyst for the asymmetric reduction reaction of prochiral aromatic ketones,and provides a novel potential route to produce enantiopure aromatic alcohols.

A challenge in chemical engineering is the separation and purification of rare-earth elements and their compounds. We report the design and manufacture of a dielectrophoresis(DEP) microchip of microelectrode arrays. This microchip device is constructed in order to use DEP to capture micro-particles of rare-earth oxides in petroleum. Dielectrophoretic behavior of micro-particles of rare-earth oxides in oil media is explored. The dielectrophoretic effects of particles under different conditions are investigated. It is showed that the prepared microchip is suitable for use in the investigation of dielectrophoretic responses of the rare-earth oxides in oil media. The factors such as frequency,particle size and valence of rare-earth metal are discussed. When the frequency is fixed,the translation voltage decreases as particle size increases. Lower frequencies are more effective for manipulation of inorganic particles in oil media. Particles of the same rare-earth oxide with different size,as well as particles of different rare-earth oxides,are captured in different regions of the field by regulating DEP conditions. This may be a new method for separation and purification of particles of different rare-earth oxides,as well as classification of particles with different size.

This paper deals with the experimental investigation on Nusselt number,friction factor and thermal enhancement factor of a double pipe heat exchanger equipped with twisted tape consisting wire nails(WN-TT) and plain twisted tapes(P-TT) with three different twist ratios of y=2.0,4.4 and 6.0. Test runs are conducted using the water as the working fluid with Reynolds number range between 2000 and 12000 for WN-TT and P-TT. It is found that Nusselt number,friction factor and thermal enhancement factor in the tube equipped with WN-TT appreciably higher than those in the tube fitted with P-TT and plain tube. Over the range considered Nusselt number,friction factor and thermal enhancement factor in a tube with WN-TT are respectively,1.08 to 1.31,1.1 to 1.75 and 1.05 to 1.13 times of those in tube with P-TT. The better performance of WN-TT is due to combined effects of the following factors:(1) common swirling flow generated by P-TT,(2) additional turbulence offered by the wire nails. Empirical correlations for Nusselt number,friction factor and thermal enhancement factor are also formulated from the experimental results of WN-TT and P-TT.