For engineering applications ofwater dilution controlling system, the fluid dynamics of a mixed flowwas studied with computational fluid dynamics (CFD) simulations and self-designed experimental set-up. In order to examine the predictability of CFDmodel for the headbox in industrial scale, two pulp suspensions beforemixingwere treated as homogeneous flows separately. Standard k-ε turbulence models with the mass diffusion in turbulent flows-species transport approach were applied in the simulations. A numerical simulation of this headbox model was analyzed with semi-implicit method for pressure linked equations scheme with pressure-velocity coupling. Results show that themodel can predict hydrodynamic characteristics of headbox with injecting dilution water in a central diffusion tube, and the distribution of water content at the outlet of the slice lip is ideally normal at different speeds.

The behaviors of time-dependent interaction between two buoyancy-driven in-line deformable drops rising in pure glycerin at Re<1 were studied, where the diameter for the leading drops ranged from 9.51 mm to 12.6 mm and for trailing drops from 12.7 mm to 15.8 mm. The situation while a larger drop chasing a smaller onewas specifically consideredwhich typically led to the smaller drop "coating" the larger one. Two approaches, the geometric feature approach and the energy change one, were used to judge the starting and ending times of the interaction between twodrops. Based on a conicalwakemodel, the drag coefficient of twoapproaching drops was calculated. Due to the approaching effect of the trailing drop, the leading drop was accelerated and the average drag coefficientwas smaller than that for a free rising single drop. The frequency spectrums of the lateral oscillation of two drops during the interaction were obtained by using Fourier analysis. The oscillation frequency of the interactional drops was also different from that for a free rising single drop because of the wake effect produced by the leading drop. Due to a superposition of the drop shape oscillation and the drop internal circulation, the transverse oscillation frequencies of two drops have the same trend during the approaching process.

Hydrodynamics of conical fluidized bed differ from that of columnar beds by the fact that a velocity gradient exists along the axial direction of the bed. The gas-liquid-solid fluidized bed has emerged in recent years as one of the most promising devices for three-phase operations. Such a device is of considerable industrial importance as evident from its wide applications in chemical, refining, petrochemical, biochemical processing, pharmaceutical and food industries. To explore this, a series of experiments have been carried out for homogeneous well-mixed ternary mixtures of dolomite of varying compositions in a three-phase conical fluidized bed. The hydrodynamic characteristics determined included the bed pressure drop, bed fluctuation and bed expansion ratios. The single and combined effects of operating parameters such as superficial gas velocity, superficial liquid velocity, initial static bed height, average particle size and cone angle on the responses have been analyzed using response surface methodology (RSM). A 2⁵ full factorial central composite experimental design has been employed. Analysis of variance (ANOVA) showed a high coefficient of determination value and satisfactory prediction second-order regression models have been derived. Experimental values of bed pressure drop, bed fluctuation and bed expansion ratios have been found to agree well with the developed correlations.

A fast and selective adsorbent for Hg(II) from aqueous solutions using thiourea (TU) functionalized polypropylene fiber grafted acrylic acid (PP-g-AA), PP-g-AA-TU fibers,was characterized by Fourier transforminfrared spectroscopy and X-ray photoelectron spectroscopy. The adsorption behavior of the functionalized chelating fibers for Hg(II) was investigated by static adsorption experiments, and the effects of some essential factors on adsorption of Hg(II) were examined, such as pH, initial concentration, adsorption time, coexisting cations, and temperature. The results showed that the adsorptive equilibrium could be achieved in 10 min, and the equilibrium adsorption quantity of PP-g-AA-TU fibers was 20 times that of PP-g-AA fibers. The PP-g-AA-TU fibers showed a very high adsorption rate and a good selectivity for Hg(II) over a wide range of pH. The adsorption isotherm can be well described with Langmuir model, with the maximum adsorption capacity for Hg(II) up to 52.04 mg·g^-1 and the removal of Hg(II) more than 97%. The kinetic data indicate that the adsorption process is best-fitted into the pseudo-second-order model.

A series of novel silica-based hybrid adsorbents were prepared by the crosslinking reaction of N-[3-(trimethoxysilyl)propyl] ethylene diamine (TMSPEDA)with epichlorohydrin (ECH) via a sol-gel process. Fourier transforminfrared (FTIR) spectra confirmed that the reaction occurred. TGA curves showed that the thermal stability of these hybrid adsorbents reached as high as 180℃. As a typical example, the adsorption performance of nickel(II) ions onto an adsorbent (the volume ratio of TMSPEDA and ECH was 4:1) was explored. It was found that the adsorption of nickel(II) ions onto this adsorbent followed the Lagergren pseudo-second-order kinetic model. The investigation of the adsorption mechanism demonstrated that nickel(II) adsorption was chiefly controlled by diffusion-chemisorption, suggesting that more diffusion processes were involved in the adsorption of nickel(II) ions onto this type of adsorbents. Desorption experiment indicates that these hybrid adsorbents can be regenerated. These findings reveal that this type of silica-based hybrid adsorbent is promising in the separation and recovery of nickel(II) ions from Ni-containing wastewater or contaminated water.

Reactive distillation and dividing wall column distillation are two kinds of effective separation technologies, and their integrated configuration, reactive dividing wall column (RDWC), presents attractive advantages. In this study, the rigorous simulation of RDWC for methyl acetate hydrolysis is performed, and sensitivity analysis is conducted to obtain the minimum reboiler duty. Then a comparison is made between the conventional process and RDWC process, and it shows that 20.1% energy savings can be achieved by RDWC process. In addition, the dynamic characteristic of RDWC is studied and an effective control strategy is proposed. The simple PI control scheme with three temperature loops can obtain reasonable control performance and maintain products at desired purities. It is proved that this RDWC process is an energy efficiency alternative with good controllability.

This study describes the treatment of composting leachate by the combination of coagulation and nanofiltration process. Poly ferric sulfate (PSF) was used as coagulant, and the effect of pH value and PSF dosage on the coagulation performance was investigated. The results indicated that the chemical oxidation demand (COD) and turbidity removal efficiency could reach to 62.8% and 75.3%, respectively at an optimum dosage of 1200 mg·L^-1 at pH 6.0. During the nanofiltration process, the operation conditions such as temperature and pressure were optimized, 89.7% of COD, 78.2% of TOC, 72.5% of TN, 83.2% of TP, and 78.6% of NH₃-Nwere retained when tested at 0.6 MPa at 25℃. The final leachate effluent concentration of COD, BOD₅, NH₃-N, TOC, SS was 92 mg·L^-1, 31mg·L^-1, 21mg·L^-1, 73mg·L^-1 and 23mg·L^-1, respectively, which reached the local discharge standard. The combination of coagulation-filtration is useful for composting leachate treatment.

As amajor configuration of membrane elements,multi-channel porous inorganicmembrane tubeswere studied by means of theoretical analysis and simulation. Configuration optimization of a cylindrical 37-channel porous inorganic membrane tube was studied by increasing membrane filtration area and increasing permeation efficiency of inner channels. An optimal ratio of the channel diameter to the inter-channel distance was proposed so as to increase the total membrane filtration area of themembrane tube. The three-dimensional computational fluid dynamics (CFD) simulationwas conducted to study the cross-flow permeation flow of purewater in the 37-channel ceramic membrane tube. A model combining Navier-Stokes equation with Darcy's law and the porous jump boundary conditions was applied. The relationship between permeation efficiency and channel locations, and the method for increasing the permeation efficiency of inner channels were proposed. Some novel multichannel membrane configurations with more permeate side channels were put forward and evaluated.

L-phenylalanine, one of the nine essential amino acids for the human body, is extensively used as an ingredient in food, pharmaceutical and nutrition industries. A suitable equilibrium model is required for purification of L-phenylalanine based on ion-exchange chromatography. In this work, the equilibrium uptake of L-phenylalanine on a strong acid-cation exchanger SH11 was investigated experimentally and theoretically. A modified Donnan ion-exchange (DIX)model,which takes the activity into account, was established to predict the uptake of L-phenylalanine at various solution pH values. The model parameters including selectivity andmean activity coefficient in the resin phase are presented. The modified DIXmodel is in good agreementwith the experimental data. The optimum operating pH value of 2.0, with the highest L-phenylalanine uptake on the resin, is predicted by themodel. This basic information combined with the general mass transfer model will lay the foundation for the prediction of dynamic behavior of fixed bed separation process.

The batch reaction experiments have been made for the first time to investigate the effect of ionic structure on the reactivity and selectivity of the trioxane-forming reaction catalyzed by a Brønsted-acidic ionic liquid (IL). The ILs considered include 1-cyclohexyl-2-pyrrolidinonium trifluoromethanesulfonate ([NCyP][TfO]), 1-cyclohexyl-2-pyrrolidinonium benzenesulfonate ([NCyP][BSA]), 1-cyclohexyl-2-pyrrolidinonium p-toluenesulfonate ([NCyP][p-TSA]), 1-octyl-2-pyrrolidinonium 2,4-dinitrobenzenesulfonate ([NOP][DNBSA]), 1-octyl-2-pyrrolidinonium benzenesulfonate ([NOP][BSA]), 1-octyl-2-pyrrolidinonium methanesulfonate ([NOP][MSA]), and 1-octyl-2-pyrrolidinonium trifluoromethanesulfonate ([NOP][TfO]). It is found that the yield of trioxane in the reaction solution correlates inversely with the Hammett acidity function H₀ of the aqueous solution of the corresponding ILs. Variation of the cation structure from[NCyP]⁺ to[NOP]⁺ exerts little influence on the yield and the selectivity of trioxane in the reaction solution. Using[TfO]^- or[DNBSA]^- in place of[MSA]^- or[BSA]^- apparently increases the yield of trioxane, but only slightly increases the concentration of formic acid in the reaction solution. The continuous production experiments have been made to investigate the performance of[NOP][MSA],[NOP][DNBSA],[NCyP][TfO], and H₂SO₄ as an extraction distillation agent. Such effect of[NCyP][TfO] considerably overrides that of H₂SO₄. The yield and the selectivity of trioxane are both increased when[NCyP][TfO] is used instead of H₂SO₄ at a reaction time 5 h.

Control of the fed-batch ethanol fermentation processes to produce maximum product ethanol is one of the key issues in the bioreactor system. However, ethanol fermentation processes exhibit complex behavior and nonlinear dynamics with respect to the cell mass, substrate, feed-rate, etc. An improved dual heuristic programming algorithm based on the least squares temporal difference with gradient correction (LSTDC) algorithm (LSTDC-DHP) is proposed to solve the learning control problem of a fed-batch ethanol fermentation process. As a new algorithm of adaptive critic designs, LSTDC-DHP is used to realize online learning control of chemical dynamical plants, where LSTDC is commonly employed to approximate the value functions. Application of the LSTDC-DHP algorithmto ethanol fermentation process can realize efficient online learning control in continuous spaces. Simulation results demonstrate the effectiveness of LSTDC-DHP, and showthat LSTDC-DHP can obtain the near-optimal feed rate trajectory faster than other-based algorithms.

Chinese rice wine making is a typical simultaneous saccharification and fermentation (SSF) process. During the fermentation process, temperature is one of the key parameters which decide the quality of Chinese rice wine. To optimize the SSF process for Chinese rice wine brewing, the effects of temperature on the kinetic parameters of yeast growth and ethanol production at various temperatureswere determined in batch cultures using amathematical model. The kinetic parameters as a function of temperature were evaluated using the software Origin8.0. Combing these functions with the mathematical model, an appropriate form of the model equations for the SSF considering the effects of temperature were developed. The kinetic parameters were found to fit the experimental data satisfactorilywith the developed temperature-dependent model. The temperature profile formaximizing the ethanol production for ricewine fermentationwas determined by genetic algorithm. The optimumtemperature profile began at a lowtemperature of 26℃ up to 30 h. The operating temperature increased rapidly to 31.9℃, and then decreased slowly to 18℃ at 65 h. Thereafter, the temperature was maintained at 18℃ until the end of fermentation. A maximum ethanol production of 89.3 g·L^-1 was attained. Conceivably, our model would facilitate the improvement of Chinese rice wine production at the industrial scale.

Currently, some fault prognosis technology occasionally has relatively unsatisfied performance especially for incipient faults in nonlinear processes duo to their large time delay and complex internal connection. To overcome this deficiency,multivariate time delay analysis is incorporated into the high sensitive local kernel principal component analysis. In this approach, mutual information estimation and Bayesian information criterion (BIC) are separately used to acquire the correlation degree and time delay of the process variables. Moreover, in order to achieve prediction, time series prediction by back propagation (BP) network is applied whose input is multivariate correlated time series other than the original time series. Then the multivariate time delayed series and future values obtained by time series prediction are combined to construct the input of local kernel principal component analysis (LKPCA)model for incipient fault prognosis. The newmethod has been exemplified in a simple nonlinear process and the complicated Tennessee Eastman (TE) benchmark process. The results indicate that the new method has superiority in the fault prognosis sensitivity over other traditional fault prognosis methods.

In this paper, an oil well production scheduling problem for the light load oil well during petroleum field exploitation was studied. The oil well production scheduling was to determine the turn on/off status and oil flow rates of thewells in a given oil reservoir, subject to a number of constraints such as minimumup/down time limits and well grouping. The problem was formulated as a mixed integer nonlinear programming model that minimized the total production operating cost and start-up cost. Due to the NP-hardness of the problem, an improved particle swarm optimization (PSO) algorithm with a new velocity updating formula was developed to solve the problemapproximately. Computational experiments on randomly generated instanceswere carried out to evaluate the performance of the model and the algorithm's effectiveness. Compared with the commercial solver CPLEX, the improved PSO can obtain high-quality schedules within a much shorter running time for all the instances.

The output feedback model predictive control (MPC), for a linear parameter varying (LPV) process system including unmeasurable model parameters and disturbance (all lying in known polytopes), is considered. Some previously developed tools, including the norm-bounding technique for relaxing the disturbance-related constraint handling, the dynamic output feedback law, the notion of quadratic boundedness for specifying the closed-loop stability, and the ellipsoidal state estimation error bound for guaranteeing the recursive feasibility, are merged in the control design. Some previous approaches are shown to be the special cases. An example of continuous stirred tank reactor (CSTR) is given to show the effectiveness of the proposed approaches.

Extracts of elephant grass (Pennisetum purpureum) blended with some intensifier halides like ammonium chloride (AMC) and potassiumiodide (PTI) were investigated as corrosion inhibitor formild steel. The corrosion processwasmonitored in 3.5% HCl bymass loss and electrochemical techniques at 30, 40, 50, 60 and 90℃. Addition of AMC and PTI increased the inhibition efficiencywith the highest inhibition efficiency obtainedwith PTI blended extract. The blends behaved as mixed type inhibitors and were spontaneously adsorbed onmild steel surface in exothermic nature. Synergistic parameters of the intensifier ions revealed cooperative effect. Kinetic data treatment indicated increase in energy barrier by intensifier ions. The results demonstrate that elephant grass extract blended with halide ions can act as alternative ecofriendly inhibitor for mild steel at elevated temperatures.

Dyes often include toxic, carcinogenic compounds and are harmful to humans' health. Therefore, removal of dyes fromtextile industry wastewater is essential. The present study aimed to evaluate the efficiency of the combination of zero valent iron (ZVI) powder and multi-walled carbon nanotubes (MWCNTs) in the removal of Reactive Red 198 (RR198) dye from aqueous solution. This applied research was performed in a batch system in the laboratory scale. This study investigated the effect of various factors influencing dye removal, including contact time, pH, adsorbent dose, iron powder dose, initial dye concentration, and temperature. The equilibrium adsorption data were analyzed using three common adsorption models:Langmuir, Freundlich and Temkin. Besides, kinetic and thermodynamic parameterswere used to establish the adsorption mechanism. The results showed, in pH=3, contact time=100min, ZVI dose=5000mg·L^-1, andMWCNTs dose=600 mg·L^-1 in 100mg·L^-1 dye concentration, the adsorption efficiency increased to 99.16%. Also, adsorption kinetics was best described by the pseudo-second-ordermodel. Equilibriumdata fitted wellwith the Freundlich isotherm(R²=0.99). The negative values of ΔG₀ and the positive value of ΔH₀ (91.76) indicate that the RR198 adsorption process is spontaneous and endothermic. According to the results, the combination of MWCNTs and ZVI was highly efficient in the removal of azo dyes.

Accurate calculation of thermodynamic properties of electrolyte solution is essential in the design and optimization of many processes in chemical industries. A new electrolyte equation of state is developed for aqueous electrolyte solutions. The Carnahan-Starling repulsive model and an attractive term based on square-well potential are adopted to represent the short range interaction of ionic and molecular species in the new electrolyte EOS. The long range interaction of ionic species is expressed by a simplified version ofMean Spherical Approximation theory (MSA). The newequation of state also contains a Born termfor charging free energy of ions. Three adjustable parameters of new eEOS per each electrolyte solution are size parameter, square-well potential depth and square-well potential interaction range. The new eEOS is applied for correlation of mean activity coefficient and prediction of osmotic coefficient of various strong aqueous electrolyte solutions at 25℃ and 0.1 MPa. In addition, the extension of the new eEOS for correlation of mean activity coefficient and solution density of a few aqueous electrolytes at temperature range of 0 to 100℃ is carried out.

The search and development of anti-HIV drugs is currently one of themost urgent tasks of pharmacological studies. In this work, a quantitative structure-activity relationship (QSAR) model based on some new norm indexes, was obtained to a series ofmore than 150 HEPT derivatives (1-[(2-hydroxyethoxy)methyl]-6-(phenylthio)thymine) to find their pEC₅₀ (the required effective concentration to achieve 50% protection ofMT-4 cells against the cytopathic effect of virus) and pCC₅₀ (the required cytotoxic concentration to reduce visibility of 50% mock infected cell) activities. The model efficiencies were then validated using the leave-one-out cross validation (LOO-CV) and yrandomization test. Results indicated that this new model was efficient and could provide satisfactory results for prediction of pEC₅₀ and pCC₅₀ with the higher R_train² and the higher R_test². By using the leverage approach, the applicability domain of this model was further investigated and no response outlier was detected for HEPT derivatives involved in this work. Comparison results with reference methods demonstrated that this new method could result in significant improvements for predicting pEC₅₀ and pCC₅₀ of anti-HIV HEPT derivatives. Moreover, results shown in this present study suggested that these two absolutely different activities pEC₅₀ and pCC₅₀ of anti-HIV HEPT derivatives could be predicted well with a totally similar QSAR model, which indicated that this model might have the potential to be further utilized for other biological activities of HEPT derivatives.

In this study, the quasi-static ebulliometric method was used to measure both of the vapor pressures of methyl N-phenyl carbamate (MPC), and the isobaric vapor-liquid equilibrium (VLE) data of the aniline and MPC binary system. The measured vapor pressure data of MPC, at different temperature ranging from 369.60 to 389.54 K, fitted well with the Antoine equation. The VLE data for the aniline and MPC system at (2.00, 4.00, 6.00, 7.00 and 8.00) kPa were correlated by both of nonrandom two-liquid (NRTL) and Wilson models. The parameters of the two models were obtained by regressing the experimental data,with the absolute temperature deviations of 0.54 K and 0.53 K, respectively. The relative volatility of the binary system calculated was all far more than 1, which gives the conclusion that the high purity MPC can be separated from aniline and MPC binary system by rectification or distillation technology.

Hydrodynamic cavitation, a newly developed process intensification technique, has demonstrated immense potential for intensifying diverse physical and chemical processes. In this study, hydrodynamic cavitation was explored as an efficient method for the formation of sub-100 nm oil-in-water (O/W) emulsions with high stability. O/W emulsion with an average droplet size of 27 nm was successfully prepared. The average droplet size of O/Wemulsions decreased with the increase of the inlet pressure, number of cavitation passes and surfactant concentration. The formed emulsion exhibited admirable physical stability during 8 months. Moreover, the hydrodynamic cavitationmethod can be generalized to fabricate large varieties of O/Wemulsions,which showed great potential for large-scale formation of O/Wemulsions with lower energy consumption.

In this work, hybrid material CNTs@MIL-101(Cr) was synthesized in 2 h using multi-walled carbon nanotubes (MWCNTs) as the crystal growth accelerator with hydrothermalmethod. The characteristic differences between the crystals of CNTs@MIL-101(Cr) and MIL-101were investigated by N2 adsorption-desorption isotherms, X-ray diffraction (XRD), scanning electron microscope (SEM) and thermogravimetric analyzer (TGA). The results showed that MWCNTs embedding in the hybrid material provide more mesoporous volumes than that of MIL-101. Moreover, the fast synthesized crystals of CNTs@MIL-101(Cr) still preserve the octahedral shape like MIL-101 and have a larger size ranging from 1.5 to 2.0 μm which were approximately three times larger than that of MIL-101. In the proposed mechanism, the roles of MWCNTs played in the crystallization were discussed where MWCNTs can be seen as coaxial cylindrical tubes composed of multi-layer graphenes and the place where nucleation and crystal growth processes occur at the tubes' out surface. Then, a crystal seeding layer bonding with the MWCNTs may be easily formed which accelerates the growth rate of MIL-101 crystals. Thus, larger crystals of CNTs@MIL-101(Cr) were formed due to the faster crystal growth rate of MIL-101.

Dissolution kinetics of sodiumcarbonate is investigatedwith the image analysismethod at the approach of single particle. The dissolution experiments are carried out in an aqueous solution under a series of controlled temperature and pH. The selected sodium carbonate particles are all spherical with the same mass and diameter. The dissolution process is quantified with the measurement of particle diameter from dissolution images. The concentration of dissolved sodium carbonate in solvent is calculated with the measured diameter of particle. Both surface reaction model and mass transport model are implemented to determine the dissolution mechanism and quantify the dissolution rate constant at each experimental condition. According to the fitting results with both two models, it is clarified that the dissolution process at the increasing temperature is controlled by the mass transport of dissolved sodium carbonate travelling from particle surface into solvent. The dissolution process at the increasing pH is controlled by the chemical reaction on particle surface. Furthermore, the dissolution rate constant for each single spherical sodium carbonate particle is quantified and the results show that the dissolution rate constant of single spherical sodiumcarbonate increases significantly with the rising of temperature, but decreases with the increasing of pH conversely.