Large surface areas nano-scale zirconia was prepared by the self-assembly route and was employed as support in nickel catalysts for the CO selective methanation. The effects of Ni loading and the catalyst calcination temperature on the performance of the catalyst for CO selective methanation reaction were investigated. The catalysts were characterized by Brunauer-Emmett-Teller (BET), transmission electron microscope (TEM), X-ray diffraction (XRD) and temperature-programmed reduction (TPR). The results showed that the as-synthesized Ni/nano-ZrO₂ catalysts presented high activity for CO methanation due to the interaction between Ni active particle and nano zirconia support. The selectivity for the CO methanation influenced significantly by the particle size of the active Ni species. The exorbitant calcination resulted in the conglomeration of dispersive Ni particles and led to the decrease of CO methanation selectivity. Among the catalysts studied, the 7.5% (by mass) Ni/ZrO₂ catalyst calcinated at 500℃ was the most effective for the CO selective methanation. It can preferentially catalyze the CO methanation with a higher 99% conversion in the CO/CO₂ competitive methanation system over the temperature range of 260-280℃, while keeping the CO₂ conversion relatively low.

A new electrochemical reactor with rotating cylindrical electrodes was designed and used to increase the regeneration efficiency of chelated iron desulfurization solution. The influence of operating parameters, such as the rotation speed of electrode, voltage, and inlet air and liquid flow rates, on the regeneration rate was investigated. Compared with the traditional tank-type reactor, the regeneration rate with the new electrochemical reactor was increased significantly. Under the optimum conditions, the regeneration rate was increased from 45.3% to 84.8%. Experimental results of continuous operation indicated that the new electrochemical regeneration method had some merits including higher regeneration efficiency, smaller equipment size and good stability in operation.

This paper considers dealing with path constraints in the framework of the improved control vector iteration (CVI) approach. Two available ways for enforcing equality path constraints are presented, which can be directly incorporated into the improved CVI approach. Inequality path constraints are much more difficult to deal with, even for small scale problems, because the time intervals where the inequality path constraints are active are unknown in advance. To overcome the challenge, the l₁ penalty function and a novel smoothing technique are introduced, leading to a new effective approach. Moreover, on the basis of the relevant theorems, a numerical algorithm is proposed for nonlinear dynamic optimization problems with inequality path constraints. Results obtained from the classic batch reactor operation problem are in agreement with the literature reports, and the computational efficiency is also high.

Multi-model approach can significantly improve the prediction performance of soft sensors in the process with multiple operational conditions. However, traditional clustering algorithms may result in overlapping phenomenon in subclasses, so that edge classes and outliers cannot be effectively dealt with and the modeling result is not satisfactory. In order to solve these problems, a new feature extraction method based on weighted kernel Fisher criterion is presented to improve the clustering accuracy, in which feature mapping is adopted to bring the edge classes and outliers closer to other normal subclasses. Furthermore, the classified data are used to develop a multiple model based on support vector machine. The proposed method is applied to a bisphenol A production process for prediction of the quality index. The simulation results demonstrate its ability in improving the data classification and the prediction performance of the soft sensor.

Molecular dynamics simulation with an all-atom force field has been carried out on the two binary systems of [bmim][PF₆]-CO₂ and [bmim][NO₃]-CO₂ to study the transport properties, volume expansion and microstructures. It was found that addition of CO₂ in the liquid phase can greatly decrease the viscosity of ionic liquids (ILs) and increase their diffusion coefficient obviously. Furthermore, the volume expansion of ionic liquids was found to increase with the increase of the mole fraction of CO₂ in the liquid phase but less than 35% for the two simulated systems, which had a significant difference with CO₂ expanded organic solvents. The main reason was that there were some void spaces inter and intra the molecules of ionic liquids. Finally, site to site radial distribution functions and corresponding number integrals were investigated and it was found that the change of microstructures of ILs by addition CO₂ had a great influence on the properties of ILs.

Vapor-liquid equilibrium (VLE) data for water + 2-propanol + 1-butyl-3-methylimidazolium chloride ([bmim]Cl) were measured. Six sets of complete T, x, y data are reported, in which the 2-propanol mole fraction on IL-free basis is fixed separately at 0.1, 0.2, 0.4, 0.6, 0.8, and approximate 0.98, while the IL mass fraction is varied from 0.1 to 0.8, in an interval of 0.1. The non-random-two-liquid (NRTL) and electrolyte non-random-two-liquid (eNRTL) equations are used to correlate the experimental data with satisfactory results. The ternary VLE behavior is also modeled with the parameters obtained by correlating two data sets, in which the mole fraction of 2-propanol on IL-free basis is approximately 0.1 and 0.98. In this way, the six sets of data are reproduced satisfactorily. With the eNRTL model, the root-mean-square deviation for temperature is 0.82 K and that for vapor-phase mole fraction is 0.0078. The influences of IL on activity coefficients and relative volatility of the volatile components are also graphically illustrated.

The solubility data of diosgenin in mixed systems of ethanol + 1-propanol (1:1), ethanol + 1-butanol (1:1), ethanol + isobutyl alcohol (1:1), methanol + isobutyl alcohol (1:1), methanol + isobutyl alcohol (1:4), ethanol + 1-pentanol (1:1) and carbon tetrachloride were measured over the temperature range from 289.15 K to 334.15 K by a laser monitoring observation technique at atmospheric pressure, with all mixtures mixed by volume ratio. The Apelblat equation, the ideal solution model, and the λh equation are used to correlate the solubility data. The results show that the three models agree well with the experimental data, providing essential support for industrial design and further theoretical study.

Vapor-liquid equilibrium data of hexamethyl disiloxane + vinyl acetate system at 101.3kPa were measured by using double circulating vapor-liquid equilibrium still. The thermodynamic consistency of the VLE data was examined by Herrington method. Experimental data was correlated by non-random two-liquid (NRTL), Wilson and universal quasichemical (UNIQUAC) parameter models. All the models satisfactorily correlated with the VLE data. The result showed that the NRTL model was the most suitable one to represent experimental data satisfactorily. The system had a minimum temperature azeotrope at 345.71 K and the mole azeotropic composition was 0.0541.

The solubility of ammonia in ethylene glycol is measured by an isothermal solubility equilibrium method at temperatures of (303.2, 308.2, 313.2, 318.2 and 323.2) K and total pressures of (0.030, 0.040, 0.050, 0.060, 0.070, 0.080, 0.090 and 0.101) MPa. The molality of ammonia in ethylene glycol ranges from 1.925 mol·kg1 to 8.265 mol·kg1. The experimental results are used to determine Henry's law constant of ammonia in ethylene glycol. Furthermore, experimental data are correlated by applying the thermodynamic model on the basis of extended Raoult's law, extended Henry's law, corresponding-states correlations and Pitzer's molality scale based equation. The overall average relative deviation between the calculated data and the experimental data of Henry's law constant and ammonia solubility are 2.029% and 2.164% respectively.

Mycelia pellet formed spontaneously in the process of cultivation was exploited as a biological carrier for whole-cell immobilization due to its unique structural characteristic. An innovative two-species whole-cell immobilization system was achieved by inoculating the marine-derived fungus Pestalotiopsis sp. J63 spores into culture medium containing another fungus Penicillium janthinellum P1 pre-grown mycelia pellets for 2 days without any pretreatment. In order to evaluate the biological degradation capacity of this novel constructed immobilization system, the immobilized pellets were applied to treat paper mill effluent and decolorize dye Azure B. The use of the constructed immobilization system in the effluent resulted in successful and rapid biodegradation of numerous insoluble fine fibers. The optimum conditions of immobilized procedure for maximum biodegradation capacity were determined using orthogonal design with biomass of P1 pellets 10 g (wet mass), concentration of J63 spore 2×10⁹ ml^-1, and immobilization time 2 d. The results demonstrate that immobilized pellets have more than 99% biodegradation capacity in a ten-hour treatment process. The kinetics of biodegradation fits the Michaelis-Menten equation well. Besides, the decolorization capability of immobilized pellets is more superior than that of P1 mycelia pellets. Overall, the present study offers a simple and reproducible way to construct a two-species whole-cell immobilization system for sewage treatment.

The characteristics of oxy-coal combustion for a swirl burner with a specially designed preheating chamber are studied numerically. In order to increase the accuracy in the prediction of flame temperature and ignition position, eddy dissipation concept (EDC) model with a skeletal chemical reaction mechanism was adopted to describe the combustion of volatile matter. Simulation was conducted under six oxidant stream conditions with different O₂/N₂/CO₂ molar ratios: 21/79/0, 30/70/0, 50/50/0, 21/0/79, 30/0/70 and 50/0/50. Results showed that O₂ enrichment in the primary oxidant stream is in favor of combustion stabilization, acceleration of ignition and increase of maximum flame temperature, while the full substitution of N₂ by CO₂ in the oxidant stream delays ignition and decreases the maximum flame temperature. However, the overall flow field and flame shapes in these cases are very similar at the same flow rate of the primary oxidant stream. Combustion characteristics of the air-coal is similar to that of the oxy-coal with 30% O₂ and 70% CO₂ in the oxidant stream, indicating that the rear condition is suitable for retrofitting an air-coal fired boiler to an oxy-coal one. The swirl burner with a specially designed preheating chamber can increase flame temperature, accelerate ignition and enhance burning intensity of pulverized coal under oxy-coal combustion. Also, qualitative experimental validation indicated the burner can reduce the overall NO_x emission under certain O₂ enrichment and oxy-coal combustion conditions against the air-coal combustion.

Due to the high price and formation damage of the guargum fracturing fluid, many oilfields are more and more interested in surfactant based fracturing fluids. The rheological properties of erucicamide dimethyl amidopropyl betaine (EDAB)-HCl acid blended system and its suitability as fracturing fluid were investigated in this work. The effects of pH, concentration of EDAB, and temperature on the rheological properties of the blended system were studied. The results show that addition of EDAB improved the viscosity of the system from less than 10 mPa·s to about 400 mPa·s, which could retard the acid-rock reaction to about one half at 60℃ and one quarter at 90℃ comparing to straight HCl acid, suggesting that there is sufficient time for the blended fluid to react with formation rock when it is used as fracturing fluid in an oil field. Core flow tests demonstrated that the EDAB-acid blended fluid could divert itself from high permeability formation core to low permeability one, thus ensuring proper acid placement in the target reservoirs.

A low-cost adsorbent was prepared from sludge and straw by pyrolysis in a dried state with the surface area of the adsorbent of 829.49 m²·g^-1, micropore volume of 0.176 cm²·g^-1 and average pore radius of 5.0 nm. The kinetic, equilibrium isotherm and thermodynamic characteristics of trisodium 1-(1-naphthylazo)-2-hydroxynaphthalene- 4',6,8-trisulphonate (acid scarlet 3R) onto the adsorbent from sludge and straw were investigated. The results indicated that the pseudo second order adsorption was the predominant adsorption mechanism of acid scarlet 3R. Thus, the adsorption phenomenon was suggested as a chemical process. The adsorption data were fitted better with Langmuir model than Freundlich model, indicating that the adsorption of acid scarlet 3R belonged to the monolayer adsorption and mainly occurred in micropores.

Large-eddy simulation of spray combustion is under its rapid development. Different combustion models were used by different investigators. However, these models are less validated by detailed experimental data. In this paper, large-eddy simulation (LES) of ethanol spray-air combustion was made using an Eulerian-Lagrangian approach, a subgrid-scale kinetic energy stress model, and a filtered finite-rate combustion model, neglecting the sub-grid scale reaction rate. The simulation results are compared with experimental dada in the literature and validated in detail. The LES obtained statistically averaged gas temperature is in much better agreement with the experimental results than Reynolds averaged (RANS) modeling using the most complex probability density function (PDF) equation combustion model. The instantaneous LES results show the coherent structures of the shear region near the high-temperature flame zone and the fuel vapor concentration map, indicating that the droplets are concentrated in this shear region. The instantaneous temperature, oxygen and carbon dioxide concentration maps show the close in-teraction between the coherent structures and the combustion reaction.

The crystal morphology of zinc lactate trihydrate in the absence or presence of impurities (viz. succinic acid, L-malic acid and D-malic acid) is investigated by molecular simulation based on surface docking model and COMPASS force field. Combing simulation results with our previous experimental results, it is found that the solvent mainly has an inhibition effect on the (0 0 2) surface, and succinic acid impurity will inhibit the growth of (0 0 2) and (0 1 1) surfaces while two enantiomers of malic acid impurity will inhibit the (0 0 2) and (1 0 0) surfaces, which are in good agreement with the experimental results.

This study investigated the hydrogenation of silicon tetrachloride (SiCl₄) in microwave plasma. A new launcher of argon (Ar) and hydrogen (H₂) plasma was introduced to produce a non-thermodynamic equilibrium activation plasma. The plasma state exhibited a characteristic temperature related to the equilibrium constant, which was termed "Reactive Temperature" in this study. Thus, the hydrogenation of SiCl₄ in the plasma could easily be handled with high conversion ratio and very high selectivity to trichlorosilane (SiHCl₃). The effects of SiCl₄/Ar and H₂/Ar ratios on the conversion were also investigated using a mathematical model developed to determine the optimum experimental parameters. The highest hydrogenation conversion ratio was produced at a H₂/SiCl₄ molar ratio of 1, with mixtures of SiCl₄ and H₂ to Ar molar ratio of 1.2 to 1.4. In this plasma, the special system pressure and incident power were required for the highest energy efficiency of hydrogenating SiCl₄, while the optimum system pressure varies from 26.6 to 40 kPa depending on input power, and the optimum feed gas (H₂ and SiCl₄) molar energy input was about 350 kJ·mol^-1.

A supercritical hydrothermal method was employed to prepare sub-micrometer LiFePO₄ particles with high purity and crystallinity. The structure and morphology of LiFePO₄ particles were characterized by X-ray diffraction and scanning electron microscope. The electrochemical tests were carried out to determine the reversible capacity, rate and cycling performance of the LiFePO₄ particles as cathode material for lithium ion battery. Experimental results show that solvent and calcining time have significant effects on purity, size and morphology of LiFePO₄ particles. Mixed solvent contained deionized water and ethanol is conducive to synthesize smaller and more uniform particles. The size of LiFePO₄ particles as-prepared is about 100-300 nm. The specific discharge capacities of the LiFePO₄ particles are 151.3 and 128.0 mA·h·g^-1 after first cycle at the rates of 0.1 and 1.0 C, respectively. It retains 95.0% of the initial capacity after 100 cycles at 1.0 C.

The kinetics for production of ethyl levulinate from glucose in ethanol medium was investigated. The experiments were performed in various temperatures (433-473 K) and initial glucose concentrations (0.056-0.168 mol·L^-1) with extremely low sulfuric acid as the catalyst. The results show that higher temperature can improve the conversion of glucose to ethyl levulinate, with higher yield of ethyl levulinate (44.79%, by mole) obtained at 473 K for 210 min. The kinetics follows a simplified first-order kinetic model. For the main and side reactions, the values of activation energy are 122.64 and 70.97 kJ·mol^-1, and the reaction orders are 0.985 and 0.998, respectively.