A series of 2D direct numerical simulations were performed with an accurate level set method for single drop impacts. The adopted ACLS method was validated to be efficient with perfect mass conservation in both normal and oblique impacts. A square-root correction for neck bases was modified in accuracy as well as scope of applications. In addition, process of jet formation and evolution was studied to reveal internal dynamics in drop impacts. It's found that pressure gradient and vortex are coexisting and completive reasons for jet topology while the inclined angle has a significant effect on them. Mechanisms of jet formation and evolution are different in the front and back necks. With the help of PDF distribution and correction calculation, a compromise in the competition is observed. This work lays a solid foundation for further studies of dynamics in gas-liquid flows.

This study deals with the stagnation point flow of ferrofluid over a flat plate with non-linear slip boundary condition in the presence of homogeneous-heterogeneous reactions. Three kinds of ferroparticles, namely, magnetite (Fe₃O₄), cobalt ferrite (CoFe₂O₄) and manganese zinc ferrite (Mn-ZnFe₂O₄) are taken into account with water and kerosene as conventional base fluids. The developed model of homogeneous-heterogeneous reactions in boundary layer flow with equal and unequal diffusivities for reactant and autocatalysis is considered. The governing partial differential equations are converted into system of non-linear ordinary differential equations by mean of similarity transformations. These ordinary differential equations are integrated numerically using shooting method. The effects of pertinent parameters on velocity and concentration profiles are presented graphically and discussed. We found that in the presence of Fe₃O₄-kerosene and CoFe₂O₄-kerosene, velocity profiles increase for large values of α and β whereas there is a decrement in concentration profiles with increasing values of K and K_s. Furthermore, the comparison between non-magnetic (Al₂O₃) and magnetic Fe₃O₄ nanoparticles is given in tabular form.

A functional electrocatalytic membrane reactor (ECMR) was performed for the electrocatalytic oxidation of 2,2,3,3-tetrafluoro-1-propanol (TFP) into high value-added sodium 2,2,3,3-tetrafluoropropionate (STFP). A computational fluid dynamics (CFD) technique was applied to simulate the hydrodynamic distributions along a tubular ECMR so as to provide guidance for the design and optimization of ECMR. Two-dimensional simulation with porous media model was employed to predict the properties of fluid dynamics in ECMR. The experimental investigation was carried to confirm the CFD simulation. Results showed that a uniform distribution of permeate velocity along the tubular reactor with short length and large diameter could be obtained. TFP conversion of 97.7%, the selectivity to STFP of 99.9% and current efficiency of 40.1% were achieved from the ECMR with a length of 40 mm and an inside diameter of 53 mm. The simulations were in good agreement with the experimental results.

The strontium ions extracted from the aqueous phase into 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide (C₂mimNTf₂) with dicyclohexyl-18-crown-6 (DCH18C6) was stripped effectively by supercritical CO₂ (sc-CO₂). Hexafluoroacetylacetone (HFAA)-acetonitrile was found to be an excellent modifier of sc-CO₂ to enhance the stripping efficiency. In the orthogonal array design (OAD), OA₂₅ (5⁵) matrix was employed to optimize the stripping of Sr(II) from the DCH18C6-C₂mimNTf₂ system. Effects of five experimental factors:temperature, pressure, concentration of HFAA, static and dynamic extraction times as well as each factor at five-levels on the stripping of Sr(II) were optimized. The effects of these parameters were treated by the analysis of variance (ANOVA). The results showed that Sr(II) could be nearly 100% extracted from the IL phase at 308 K, 30 MPa, 40 min of dynamic extraction and 60 mmol·L^-1 HFAA in acetonitrile, respectively. Finally, the stripping mechanism was studied by ESI-MS.

A facile method for synthesis of the magnetic Fe₃O₄ nanoparticles was introduced. Magnetic nanoparticles were prepared via co-precipitation method with (PMF) and without (AMF) 0.15 T static magnetic field. The effects of magnetic field on the properties of magnetic nanoparticles were studied by XRD, TEM, SEM, VSM and BET. The results showed that the magnetic field in the co-precipitation reaction process did not result in the phase change of the Fe₃O₄ nanoparticles but improved the crystallinity. The morphology of Fe₃O₄ nanoparticles was varied from random spherical particles to rod-like cluster structure. The VSM results indicated that the saturation magnetization value of the Fe₃O₄ nanoparticles was significantly improved by the magnetic field. The BET of Fe₃O₄ nanoparticles prepared with the magnetic field was larger than the control by 23.5%. The batch adsorption experiments of Mn(II) on the PMF and AMF Fe₃O₄ nanoparticles showed that the Mn(II) equilibrium capacity was increased with the pH value increased. At pH 8, the Mn(II) adsorption capacity for the PMF and AMF Fe₃O₄ was reached at 36.81 and 28.36 mg·g^-1, respectively. The pseudo-second-order model fitted better the kinetic models and the Freundlich model fitted isotherm model well for both PMF and AMF Fe₃O₄. The results suggested that magnetic nanoparticles prepared by the magnetic field presented a fairly good potential as an adsorbent for an efficient removal of Mn(II) from aqueous solution.

The study deals with adsorption of Naphthol Green B on two unburned carbons and the parent coal, from which the UCs have been created in a fluidised-bed power station. Particular attention has been paid to the adsorption equilibrium modelling:experimental data has been analysed using 2-parameter (Langmuir, Freundlich) and 3-parameter (Redlich-Peterson) isotherms-both linear and non-linear regressions have been used for the estimation of the isotherm parameters. In the case of both UCs, the Langmuir isotherm model provides the worst fit, whereas 2-parameter Freundlich and 3-parameter Redlich-Peterson models are both good, from which 3-parameter Redlich-Peterson isotherm provides slightly better results (despite the penalty used for the higher number of parameters). In the case of both UCs, the linear regression of Freundlich and Redlich-Peterson models provides good results (comparable with non-linear regressions). Unlike both UCs, the best fit of the experimental data from the adsorption on the coal has been achieved by the Langmuir isotherm model. The results based on the Freundlich or Redlich-Peterson model were (in this case) somewhat worse.

Phenol is considered as pollutant due to its toxicity and carcinogenic effect. Thus, variety of innovative methods for separation and recovery of phenolic compounds is developed in order to remove the unwanted phenol from wastewater and obtain valuable phenolic compound. One of potential method is extraction using green based liquid organic solvent. Therefore, the feasibility of using palm oil was investigated. In this research, palm oil based organic phase was used as diluents to treat a simulated wastewater containing 300×10^-6 of phenol solution using emulsion liquid membrane process (ELM). The stability of water-in-oil (W/O) emulsion on diluent composition and the parameters affecting the phenol removal efficiency and stability of the emulsion; such as emulsification speed, emulsification time, agitation speed, surfactant concentration, pH of external phase, contact time, stripping agent concentration and treat ratio were carried out. The results of ELM study showed that at ratio 7 to 3 of palm oil to kerosene, 5 min and 1300 r·min^-1 of emulsification process the stabile primary emulsion were formed. Also, no carrier is needed to facilitate the phenol extraction. In experimental conditions of 500 r·min^-1 of agitation speed, 3% Span 80, pH 8 of external phase, 5 min of contact time, 0.1 mol·L^-1 NaOH as stripping agent and 1:10 of treat ratio, the ELM process was very promising for removing the phenol from the wastewater. The extraction performance at about 83% of phenol was removed for simulated wastewater and an enrichment of phenol in recovery phase as phenolate compound was around 11 times.

The mass transfer process in a perforated rotating disk contactor (PRDC) using a toluene-acetone-water system was investigated. The volumetric overall mass transfer coefficients are calculated in a PRDC column. Both mass transfer directions are considered in experiments. The influences of operating variables containing agitation rate, dispersed and continuous phase flow rates and mass transfer in the extraction column are studied. According to obtained results, mass transfer is significantly dependent on agitation rate, while the dispersed and continuous phase flow rates have a minor effect on mass transfer in the extraction column. Furthermore, a novel empirical correlation is developed for prediction of overall continuous phase Sherwood number based on dispersed phase holdup, Reynolds number and mass transfer direction. There has been great agreement between experimental data and predicted values using a proposed correlation for all operating conditions.

With the rapid increase of water contamination, membrane separation technology and their corresponding molecular weight cut-off (MWCO) evaluation method become more necessary. In this study, Panax notoginseng saponins was used as a new standard marker to determinate ultrafiltration (UF) membrane MWCOs, series of Millipore membranes were selected as control group to analyze and calculate the relationship between retention rate and MWCOs with exponential or logarithmic equation. A new and convenient method was provided for determining the membrane MWCO by modeling analysis retention rate with MWCOs, and the regression coefficients ≥0.990. The feasibility and practicability of established method was verified by different manufactures' membrane and dextrans. In the detection progress, as the main ingredient of Panax notoginseng saponins, Notoginsenoside R₁, Ginsenoside Rg₁, Ginsenoside Rb₁ and Ginsenoside Rd with different surface activity, the MWCO range of UF membranes can be divided into two zones mainly due to the retention rate difference among Notoginsenoside R₁, Ginsenoside Rg₁, Ginsenoside Rb₁ and Ginsenoside Rd. Zone I, 1000-10000; and Zone II, 10000-100000. Thus, the new method would be helpful to improve the applicability of UF membrane in separation technology.

In this work, the effects of degradation time, temperature, and pH value on the degradation of Salvianolic acid B in aqueous solution were determined. Higher pH values, higher extraction temperature, and longer extraction time led to more degradation of Salvianolic acid B. Danshensu concentration increased as Salvianolic acid B degraded. A mechanism model was developed considering the degradation of Salvianolic acid E and lithospermic acid, which were two degradation products of Salvianolic acid B. The reverse reactions of Salvianolic acid B degradation were also considered. Degradation kinetic constants were calibrated. The degradation kinetics of Salvianolic acid B, lithospermic acid, and Danshensu in a Salvia miltiorrhiza extract aqueous solution were predicted using the mechanism model. The predicted concentrations agreed well with the experimental results. This model was developed using degradation data obtained from simple composition systems, but it can be applied in a complex botanical mixture with high prediction accuracy.

The effects of adding rare earth (RE) metals, such as Ce, Yb and Pr to Ni-S₂O₈^2-/ZrO₂-Al₂O₃ (Ni-SZA) on the structure of catalysts as well as their isomerization performance were studied. The prepared catalysts were characterized by XRD, BET, FT-IR, Py-IR, and H₂-TPR. The results showed that the addition of RE metals can increase the strength and amounts of the acid sites, improve the redox properties of catalysts. The Yb-Ni-SZA catalyst showed the best redox properties, which could provide enough metallic sites. In addition, it provided the largest amounts of weak and moderately strong acid sites. Among RE metals modified Ni-SZA catalyst, Yb-Ni-SZA exhibited the highest isopentane yield of 61.7% at 160℃. The optimum isomerization catalytic performance of the catalysts decreased in the order of Yb-Ni-SZA > Pr-Ni-SZA > Ni-SZA > Ce-Ni-SZA.

Ignition delay of syngas is an important factor that affects stable operation of combustor and adding diluents to syngas can reduce NO_x emission. This paper used H₂O, CO₂ and N₂ as diluents and calculated ignition delay of syngas in temperature range of 900-1400 K and at pressures of 10 and 30 atm respectively. In high temperature range, comparing with N₂ dilution, adding H₂O and CO₂ can significantly inhibit autoignition of syngas because they have higher collision efficiencies in reaction H+O₂ (+M)=HO₂ (+M). As for low temperature conditions, adding H₂O can increase reactivity of syngas, especially under high pressure, because of its high collision efficiency in reaction H₂O₂ (+M)=2OH (+M). Comparing with different dilution rates shows that for syngas and operating conditions in this paper, adding N₂ mainly influences temperature rising process of syngas combustion, thus inhibiting reactivity of syngas. In addition, this paper calculated ignition delay of syngas at different equivalence ratios (φ=0.5, 1.0). Higher equivalence ratio (φ≤1) means that less air (especially N₂) needs to be heated, thus promoting ignition of syngas.

In this work, the impact of internal heat integration upon process dynamics and controllability by superposing reactive section onto stripping section, relocating feed locations, and redistributing catalyst within the reactive section is explored based on a hypothetical ideal reactive distillation system containing an exothermic reaction:A+B↔C+D. Steady state operation analysis and closed-loop controllability evaluation are carried out by comparing the process designs with and without the consideration of internal heat integration. For superposing reactive section onto stripping section, favorable effect is aroused due to its low sensitivities to the changes in operating condition. For ascending the lower feed stage, somewhat detrimental effect occurs because of the accompanied adverse internal heat integration and strong sensitivity to the changes in operating condition. For descending the upper feed stage, serious detrimental effect happens because of the introduced adverse internal heat integration and strong sensitivity to the changes in operating condition. For redistributing catalyst in the reactive section, fairly small negative influence is aroused by the sensitivity to the changes in operating condition. When reinforcing internal heat integration with a combinatorial use of these three strategies, the decent of the upper feed stage should be avoided in process development. Although the conclusions are derived based on the hypothetical ideal reactive distillation column studied, they are considered to be of general significance to the design and operation of other reactive distillation columns.

In this work, the dynamics and operation of the totally reboiled reactive distillation columns are visualized in terms of transfer function based process models. This kind of processes is found to be characterized by underdamped step responses due to the special topological configuration and the intricate interplay between the reaction operation and the separation operation involved. The under-dampness can be substantially alleviated through the tight inventory control of bottom reboiler and this presents beneficial effects to process dynamics and operation. Two totally reboiled reactive distillation columns, separating, respectively, a hypothetical synthesis reaction from reactants A and B to product C, and a real decomposition reaction from 1, 4-butanediol to tetrahydrofuran and water, are employed to demonstrate these uncommon behaviors. The results obtained give full support to the above qualitative interpretation. Despite the strong influences of reaction kinetics and thermodynamic properties of the reacting mixtures, the totally reboiled reactive distillation columns are generally considered to present such unique behaviors and require tight inventory control of bottom reboiler to facilitate their control system development.

The dynamic soft sensor based on a single Gaussian process regression (GPR) model has been developed in fermentation processes. However, limitations of single regression models, for multiphase/multimode fermentation processes, may result in large prediction errors and complexity of the soft sensor. Therefore, a dynamic soft sensor based on Gaussian mixture regression (GMR) was proposed to overcome the problems. Two structure parameters, the number of Gaussian components and the order of the model, are crucial to the soft sensor model. To achieve a simple and effective soft sensor, an iterative strategy was proposed to optimize the two structure parameters synchronously. For the aim of comparisons, the proposed dynamic GMR soft sensor and the existing dynamic GPR soft sensor were both investigated to estimate biomass concentration in a Penicillin simulation process and an industrial Erythromycin fermentation process. Results show that the proposed dynamic GMR soft sensor has higher prediction accuracy and is more suitable for dynamic multiphase/multimode fermentation processes.

The present study investigated the vaporization kinetics of MgCl₂, CaCl₂ and their binary melts in a fluidized bed at 1073-1273 K, and developed a vaporization model for the binary melts to explore the possibility of achieving enhanced vaporization rate for the feedstock containing CaO greater than 0.2 wt%. The vaporization rate constant of MgCl₂ is more than seven times than that of CaCl₂ at 1273 K. The vaporization rate of the binary melt was significantly affected by the composition, a small quantity of CaCl₂ can remarkably deteriorate the overall vaporization rate. Experimental results coincide well with the numerical simulation by the vaporization model which regards the evolution of vaporization rate with melts composition. A correlation between the necessary operation temperature and the CaO/(CaO+MgO) of the feedstock was proposed. Predictions reveal that a similar vaporization rate for 0.2 wt%-0.4 wt% CaO content feedstock with 0.2 wt% could be achieved at lower than 1365 K.

A new kind of silicon-based biological lubricating base oil with good viscosity-temperature behavior, viscosity index, thermostability, oxidation stability and wear resistance performance was synthesized as a derivative of methyl oleate. Trimethylsilylation reaction was introduced to further improve methyl oleate oxidation stability and lubricity after epoxidation and open-ring reactions. The order of effectiveness of acid binding agent was N,N-diisopropylethylamine (DIEA) > pyridine > diethylamine > triethylamine, and the effects of various parameters on the trimethylsilylation reaction as well as on the silicon-oxygen bond stability and reaction yield were studied. A maximum yield of 34.54% was achieved at hydroxyl/trimethyl chlorosilane/DIEA molar ratio of 1:1.25:1, reaction temperature 40℃, reaction time 1.5 h.

By varying concentration of PEG1000 as a structure-directing agent, mesoporous alumina with excellent textural properties was synthesized. The prepared mesoporous alumina displays high thermal stability, as shown by its textural properties at different calcination temperatures of 600-850℃. Characterization by SEM and TEM revealed that the added PEG surfactant induced the formation of petal-like alumina. XRD results clarified that all samples were amorphous and their peaks were around the peaks of γ-alumina. N₂ adsorption-desorption analysis showed that the prepared mesoporous alumina, if with PEG1000 in hydrolysis of aluminum isopropoxide, had excellent textural properties with large specific surface area, high pore volume and suitable pore size. The petal-like structure existing in the alumina samples improved their textural parameters, and the role and influential mechanism of PEG1000 were analyzed.