The parallel-competing iodide-iodate reaction scheme was used to study the micromixing performance in a multi-phase stirred tank of 0.3m diameter. The impeller combination consisted of a half elliptical blade disk turbine below two down-pimping wide-blade hydrofoils, identified as HEDT+2WH_D. Nitrogen and glass beads of 100 μm diameter and density 2500 kg·m^-3 were used as the dispersed phases. The micromixing could be improved by sparging gas because of its additional potential energy. Also, micromixing could be improved by the solid particles with high kinetic energy near the impeller tip. In a gas-solid-liquid system, the gas-liquid film vibrationwith damping, due to the frequent collisions between the bubbles and particles, led to the decrease of the turbulence level in the liquid and caused eventually the deterioration of themicromixing. A Damping Film Dissipation model is formulated to shed light on the above micromixing performances. At last, the micromixing time tm according to the incorporation model varied from 1.9 ms to 6.7 ms in our experiments.

This study investigates the effect of injecting nanofluids containing nano-SiO₂ as drag reducing agents (DRA) at different concentrations on the pressure drop of air-water flow through horizontal pipe. The test fluid used in this study was air-water with nano-SiO₂ particles at 0.1%-1% mass concentration. The test sections of the experimental set-up were five pipes of the same length of 9 m with ID from 0.0127m-0.03175m (0.5 to 1.25 in). Air-water flow was run in slug flow regime under different volumetric flow rates. The results of drag reduction (η%) indicated that the addition of DRA could be efficient up to some dosage. Drag reduction performed much better for smaller pipe diameters than it did for larger ones. For various nanosilica concentrations, the maximum drag reduction was about 66.8% for 0.75% mass concentration of nanosilica.

The effect of different surfactants (n-octyltrimethylammonium bromide (OTABr), sodium dodecyl benzene sulfonate (SDBS) and Tween 80) with different critical micelle concentrations (CMC) on the CO₂ absorption into aqueous solutions in a bubble column is analyzed in the present work. The presence of these surfactants increased the gas-liquid interfacial area, and decreased the liquid phase mass transfer coefficient, but with significant different extent. The results indicated that the CMC can be a key parameter affecting the mass transfer of CO₂ absorption into a dilute aqueous solution of a surfactant. Sardeing's model was used to fit the experimental data successfully by re-correlating the parameters.

The bending moment acting on the overhung shaft of a gas-sparged vessel stirred by a Rushton turbine, as one of the results of fluid and structure interactions in stirred vessels, was measured using a moment sensor equipped with digital telemetry. An analysis of the shaft bending momentamplitude shows that the amplitude distribution of the bending moment, which indicates the elasticity nature of shaftmaterial against bending deformation, follows the Weibull distribution. The trends of amplitude mean, standard deviation and peak deviation characteristics manifest an “S” shape versus gas flow. The “S” trend of the relative mean bending moment over gas flow rate, depending on the flow regime in gas-liquid stirred vessels, resulted from the competition among the nonuniformity of bubbly flow around the impeller, the formation of gas cavities behind the blades, and the gas direct impact on the impellerwhen gas is introduced. A further analysis of the bendingmoment power spectral density shows that the rather low frequency and speed frequency are evident. The low-frequency contribution to bending moment fluctuation peaks in the complete dispersion regime.

The article presents an experimental and numerical study on thermal performance enhancement in a constant heatfluxed square-duct inserted diagonallywith 45°discrete V-finned tapes (DFT). The experimentswere carried out by varying the airflow rate through the tested square duct with DFT inserts for Reynolds number from 4000 to 25000. The effect of the DFT with V-tip pointing upstream at various relative fin heights and pitches on heat transfer and pressure drop characteristics was experimentally investigated. Both the heat transfer and pressure drop were presented in terms of Nusselt number and friction factor respectively. Several V-finned tape characteristics were introduced such as fin-to duct-height ratio or blockage ratio (R_B=e/H=0.075, 0.1, 0.15 and 0.2), fin pitch to duct height ratio (R_P=P/H=0.5, 1.0, 1.5 and 2.0) and fin attack angle, α=45°. The experimental results reveal that the heat transfer and friction factor values with DFT inserts increase with the increment of R_B but the decrease of RP. The inserted square-duct at R_B=0.2 and R_P=0.5 provides the highest heat transfer and friction factor while the one with R_B=0.1 and R_P=1.5 yields the highest thermal performance. Also, a numerical simulation was conducted to investigate the flow structure and heat transfer mechanism inside the tested duct with DFT inserts.

A novel purification process is involved to obtain the high purity [>99%(by mass)] dodecanedioic acid (DC₁₂). It involves a re-crystallization followed bymolecular distillation fromthe crude product. The objective of this study is to investigate general conditions, feed rate, distilling temperature and vacuum, necessary for centrifugal distillation of DC₁₂. Under the optimum conditions, distilling temperature 180℃, pressure 30 Pa and feed flow rate 700 ml·h^-1, the purity of DC₁₂ in the residence reached 97.55% with a yield of 53.18% by the analysis of gas chromatography. Multiple-pass distillation made a considerable contribution by improving the purity to 99.22%. Additionally, the effect of pretreatment (re-crystallization) on distillation process was revealed through a series of comparative experiments.

The purification and separation of durene from the mixture containing durene isomers were studied. Since the boiling points of tetramethyl benzene isomers are very close but theirmelting points are of great differences, static melt crystallization was applied to separate and purify durene from its isomers. Crystallization experiments were carried out under various operating conditions. The effects of cooling rate, crystallization temperature, sweating temperature and sweating time on the yield and purity of crystal were investigated. Orthogonal experimental designmethodwas adopted to analyze the factors that may affect the yield of durene. Under the optimal crystallization conditions, the purity of durene could reach as high as 99.06% with the yield of 75.3% through one crystallization process. By fitting purification data based on sweating time in isothermal operations, the purification rate coefficient was obtained.

A simple ultrasound-assisted co-precipitation method was developed to prepare ferroferric oxide/graphene oxide magnetic nanoparticles (Fe₃O₄/GO MNPs). The hysteresis loop of Fe₃O₄/GO MNPs demonstrated that the sample was typical of superparamagnetic material. The samples were characterized by transmission electron microscope, and it is found that the particles are of small size. The Fe₃O₄/GO MNPs were further used as an adsorbent to remove Rhodamine B. The effects of initial pH of the solution, the dosage of adsorbent, temperature, contact time and the presence of interfering dyes on adsorption performance were investigated as well. The adsorption equilibrium and kinetics data were fitted well with the Freundlich isotherm and the pseudosecond-order kinetic model respectively. The adsorption process followed intra-particle diffusion model with more than one process affecting the adsorption of Rhodamine B. And the adsorption process was endothermic in nature. Furthermore, the magnetic composite with a high adsorption capacity of Rhodamine B could be effectively and simply separated using an external magnetic field. And the used particles could be regenerated and recycled easily. The magnetic composite could find potential applications for the removal of dye pollutants.

The catalytic activity of carbon nanotubes-supported vanadium oxide (V₂O₅/CNTs) catalysts in the selective catalytic reduction (SCR) of NO with NH₃ at low temperatures (≤250℃) was investigated. The effects of V₂O₅ loading, reaction temperature, and presence of SO₂ on the SCR activity were evaluated. The results show that V₂O₅/CNTs catalysts exhibit high activity for NO reduction with NH₃ at low-temperatures. The catalysts also show very high stability in the presence of SO₂.More interestingly, their activities are significantly promoted instead of being poisoned by SO₂. The promoting effect of SO₂ is distinctly associatedwith V₂O₅ loading, particularly maximized at low V₂O₅ loading, which indicated the role of CNTs support in this effect. The promoting effect of SO₂ at lowtemperatures suggests that V₂O₅/CNTs catalysts are promising catalyticmaterials for low-temperature SCR reactions.

Isooctane is a promising gasoline additive that could be produced by dimerization of isobutene (IB) with subsequent hydrogenation. In this work, the dimerization of IB has been carried out in a batch reactor over a temperature range of 338-383 K in the presence of laboratory prepared Ni/Al₂O₃ as a catalyst and n-pentane as solvent. The influence of various parameters such as temperature, catalyst loading and initial concentration of IB was examined. A Langmuir-Hinshelwood kinetic model of IB dimerization was established and the parameters were estimated on the basis of the measured data. The feasibility of oligomerization of IB based on the reactive distillation was simulated in ASPEN PLUS using the kinetics developed. The simulation results showed that the catalyst of Ni/Al₂O₃ had higher selectivity to diisobutene (DIB) and slightly lower conversion of IB than ion exchange resin in the absence of polar substances.

In this paper, the polymer chain of rotator (PCOR) equation of state (EOS) was used together with an EOS/G^E mixing rule (MHV1) and the Wilson's equation as an excess-Gibbs-energy model in the proposed approach to extend the capability and improve the accuracy of the PCOR EOS for predicting the Henry's constant of solutions containing polymers. The results of the proposed method compared with two equation of state (van derWaals and GC-Flory) and three activity coefficient models (UNIFAC, UNIFAC-FV and Entropic-FV) indicated that the PCOR EOS/Wilson's equation provided more accurate results. The interaction parameters of Wilson's equation were fitted with Henry's constant experimental data and the property parameters of PCOR, a and b, were fitted with experimental volume data (Tait equation). As a result, the present work provided a simple and useful model for prediction of Henry's constant for polymer solutions.

The physicochemical properties, including the density, viscosity, and refractive index of aqueous solutions of sodium glycinate as a solvent for CO₂ absorption in the non-precipitation regime were measured under the wide temperature range of 298.15 to 343.15 K. The concentration of the sodium glycinate in an aqueous form in the non-precipitation regime was identified up to 2.0 mol·L^-1. The coefficients of thermal expansion values were estimated from measured density data. It was found that, the densities, viscosities and refractive indices of the aqueous sodium glycinate decrease with an increase in temperature, whereas with increasing sodium glycinate concentration in the solution, all three properties increase. Thermal expansion coefficients slightly increase with rising temperature and concentration. The measured values of density, viscosity and refractive index were correlated as a function of temperature by using the least squares method. The predicted data obtained from correlation equations for all measured properties were in fairly good agreement with the experimental data.

In this work the statistical mechanical equation of state was developed for volumetric properties of crystalline and amorphous polymer blends. The Ihm-Song-Mason equations of state (ISMEOS) based on temperature and density at melting point (T_m and ρ_m) as scaling constants were developed for crystalline polymers such as poly(propylene glycol)+poly(ethylene glycol)-200 (PPG+PEG-200), poly(ethylene glycol) methyl ether-300 (PEGME-350)+PEG-200 and PEGME-350+PEG-600. Furthermore, for amorphous polymer blends containing poly(2,6-dimethyl-1,4-phenylene oxide) (PPO)+polystyrene (PS) and PS+poly(vinylmethylether) (PVME), the density and surface tension at glass transition (ρ_g and γ_g) were used for estimation of second Virial coefficient. The calculation of second Virial coefficients (B₂), effective van derWaals co-volume (b) andcorrection factor (α) was required for judgment about applicability of this model. The obtained results by ISMEOS for crystalline and amorphous polymer blends were in good agreement with the experimental data with absolute average deviations of 0.84% and 1.04%, respectively.

The modified Siemens process, which is the major process of producing polycrystalline silicon through current technologies, is a high temperature, slow, semi-batch process and the product is expensive primarily due to the large energy consumption. Therefore, the zinc reduction process, which can produce solar-grade silicon in a cost effective manner, should be redeveloped for these conditions. The SiCl₂ generation ratio, which stands for the degree of the side reactions, can be decomposed to SiCl₄ and ZnCl₂ in gas phase zinc atmosphere in the exit where the temperature is very low. Therefore, the lower SiCl₂ generation ratio is profitable with lower power consumption. Based on the thermodynamic data for the related pure substances, the relations of the SiCl₂ generation ratio and pressure, temperature and the feed molar ratio (n_Zn=n_SiCl4) are investigated and the graphs thereof are plotted. And the diagrams of K_p^Θ-T at standard atmosphere pressure have been plotted to account for the influence of temperature on the SiCl₂ generation ratio. Furthermore, the diagram of K_p^Θ-T at different pressures have also been plotted to give an interpretation of the influence of pressure on the SiCl₂ generation ratio. The results show that SiCl₂ generation ratio increases with increasing temperature, and the higher pressure and excess gas phase zinc can restrict SiCl₂ generation ratio. Finally, suitable operational conditions in the practical process of polycrystalline silicon manufacture by gas phase zinc reduction of SiCl₄ have been establishedwith 1200 K, 0.2MPa and the feedmolar ratio (n_Zn=n_SiCl4) of 4 at the entrance.Under these conditions, SiCl₂ generation ratio is very low, which indicates that the side reactions can be restricted and the energy consumption is reasonable.

Densities (ρ) and dynamic viscosities (η) for three binary mixtures of n-decane with 1-pentanol, 1-hexanol and 1-heptanol are presented at temperatures from 293.15 to 363.15 K and atmospheric pressure over the entire composition range. The density and viscosity are measured using a vibrating tube densimeter and a cylindrical Couette type rotating viscometer, respectively. Excess molar volumes (V^E), viscosity deviations (Δη) and excess Gibbs energy of activation of viscous flow (ΔG^*E)) are calculated from the experimentalmeasurements. Intermolecular and structural interactions are indicated by the sign and magnitude of these properties. Partial molar volumes and infinity dilution molar partial volumes are also calculated for each binary system. These results are correlated using Redlich-Kister type equations.

Lowcritical temperature limits the application of CO₂ trans-critical power cycle. The binary mixture of R290/CO₂ has higher critical temperature. Using mixture fluid may solve the problem that subcritical CO₂ is hardly condensed by conventional cooling water. In this article, theoretical analysis is executed to study the performance of the zeotropic mixture for trans-critical power cycle using low-grade liquid heat source with temperature of 200℃. The results indicated that the problem that CO₂ can't be condensed in power cycle by conventional coolingwater can be solved bymixing R290 to CO₂. Variation trend of outlet temperature of thermal oil in supercritical heaterwith heating pressure is determined by the composition of the mixture fluid. Gliding temperature causes the maximum outlet temperature of cooling water with the increase of mass fraction of R290. There are themaximumvalues for cycle thermal efficiency and net power outputwith the increase of supercritical heating pressure.

In order to apply grindingmethod for degradation of pentachlorophenol (PCP) to an industrial scale, the proportion of differentmaterials [CaO, SiO₂ and CO(NH₂)₂] and the size of grinding balls were examined. For saving energy and increasing dechlorination efficiency, the rotation speed and grinding time were maintained at relatively low values. At a mass ratio of grinding balls to materials (40:1), PCP was added into a big steel jar (300 ml) with othermaterials to grind at 300 r·min^-1 for 5 h. The results indicated thatwhen PCPwasmixedwith CaOand SiO₂ in a molar ratio of 1:60:60, the best dechlorination of 58.4% was achieved. CO(NH₂)₂ could not be used as hydrogen donor in the dehalogenation bymechanochemical reaction, since it restrained the dechlorination process. The size of grinding balls has significant effect on the reaction. The experimentwith 5mmsteel balls indicates that the weight is too light to provide appropriate energy for the reaction, while steel balls of 10 and 15 mm could give better dechlorination reaction. It indicates that dechlorination depends on the mass of balls and fill rate.

Mesoporous TiO₂-B/anatase microparticles have been in-situ synthesized from K₂Ti₂O₅ without template. The TiO₂-B phase around the particle surface accelerates the diffusion of charges through the interface, while the anatase phase in the coremaintains the capacity stability. The heterojunction interface between themain polymorph of anatase and the trace of TiO₂-B exhibits promising lithiumion battery performance. This trace of 5% (by mass) TiO₂-B determined by Raman spectra brings the first discharge capacity of thismaterial to 247mA·h·g^-1, giving 20% improvement compared to the anatase counterpart. Stability testing at 1 C reveals that the capacitymaintains at 171mA·h·g^-1, which is better than 162mA·h·g^-1 for single phase anatase or 159 mA·h·g^-1 for TiO₂-B. The mesoporous TiO₂-B/anatase microparticles also show superior rate performance with 100 mA·h·g^-1 at 40 C, increased by nearly 25% as compared to pure anatase. This opens a possibility of a general design route, which can be applied to other metal oxide electrode materials for rechargeable batteries and supercapacitors.

The extraction of aluminum from coal mining waste (CMW) is an important industrial process. The two major problems in applications are low aluminum dissolution efficiency and high iron content in the raw material, which affect the quantity and quality of products. To improve the aluminumrecovery process, the leaching kinetics of CMWwith hydrochloric acid was studied. A shrinking core model was used to investigate aluminum and iron dissolution kinetics. Based on the kinetic characteristics, a process for recovering aluminum was proposed and tested experimentally. It is found that the aluminum leaching reaction is controlled by surface reaction at low temperatures (40-80℃) and by diffusion process at higher temperatures (90-106℃). The iron dissolution process is dominated by surface reaction at 40-100℃. The results showthat iron could be dissolved or separated by concentrated hydrochloric acid. Fine grinding will improve aluminum dissolution significantly.