Nanofluidics in hydrophilic nanopores is a common issue in many natural and industrial processes. Among all, the mass transport of nanofluidics is most concerned. Besides that, the heat transfer of a fluid flow in nano or micro channels is always considered with adding nanoparticles into the flow, so as to enhance the heat transfer by convection between the fluid and the surface. However, for some applications with around 1 nm channels such as nano filtration or erosion of rocks, there should be no nanoparticles included. Hence, it is necessary to figure out the heat transfer mechanismin the single phase nanofluidics. Via non-equilibrium molecular dynamics simulations, we revealed the heat transfer inside nanofluidics and the one between fluid and walls by setting simulation into extremely harsh condition. It was found that the heat was conducted by molecular motion without temperature gradient in the area of low viscous heat, while it was transferred to the walls by increasing the temperature of fluids. If the condition back to normal, it was found that the viscous heat of nanofluidics could be easily removed by the fluid-wall temperature drop of less than 1 K.

Conventionally, multiple reference frame (MRF) method and sliding mesh (SM) method are used in the simulation of stirred tanks, however, both methods have limitations. In this study, a hybrid immersed-boundary (IB) technique is developed in a finite difference context for the numerical simulation of stirred tanks. IBs based on Lagrangian markers and solid volume fractions are used for moving and stationary boundaries, respectively, to achieve optimal efficiency and accuracy. To cope with the high computational cost in the simulation of stirred tanks, the technique is implemented on computers with hybrid architecture where central processing units (CPUs) and graphics processing units (GPUs) are used together. The accuracy and efficiency of the present technique are first demonstrated in a relatively simple case, and then the technique is applied to the simulation of turbulent flow in a Rushton stirred tank with large eddy simulation (LES). Finally the proposed methodology is coupled with discrete element method (DEM) to accomplish particle-resolved simulation of solid suspensions in small stirred tanks. It demonstrates that the proposed methodology is a promising tool in simulating turbulent flow in stirred tanks with complex geometries.

To control the multicomponent reactions in extrusion, reactive-mixing flow in a co-rotating twin screw extruder was numerically studied in the present paper. Effects of initial species distribution, rotating speed and flow rate on a competitive-parallel reaction were investigated and the relationship between mixing and reactions was discussed from the view of chemical reaction engineering. The simulation results show the studied operational parameters, which determine residence time distribution, earliness of mixing and segregation degree of reactive-mixing flows, affect the local species concentration and reaction time and hence have significant influences on the reaction extent. Orthogonal test was adopted to clarify the significance of operational parameters. The analysis shows that initial species distribution and flow rate are the most important factors in the control of reaction extent, and effect of rotating speed is conditional depending on the micro-mixing status of the fluid.

In this research, the deformation of water droplets in sunflower oil-interface under pulsatile electric field was studied experimentally. Three types of coalescence were observed:(i) complete coalescence, (ii) incomplete coalescence and (iii) no-coalescence. The first type is desirable because of leaving no secondary droplets. The second type that produced secondary droplets which caused by necking process, due to extreme elongation of droplets (mostly small droplets), was undesirable; because the small droplets were more difficult to coalesce and remove. The no-coalescence was caused by very fast coalescence and extensive pushing of droplet into the continuous phase. In this work the process was operated with the utilization of a batch cylindrical separator with high voltage system. The lower part of the cylinder was filled with the aqueous phase and its top part was filled with sunflower oil to form an interface between the two phases. The effects of electric field strength, frequency, and waveform types were investigated. It was found that, the ramp-ac waveform was the best waveform, avoiding the production of secondary droplets and in this case the frequency also played an important role.

The stability of composite palladium membranes is of key importance for their application in hydrogen energy systems. Most of these membranes are prepared by electroless plating, and beforehand the substrate surface is activated by a SnCl₂-PdCl₂ process, but this process leads to a residue of Sn, which has been reported to be harmful to the membrane stability. In this work, the Pd/Al₂O₃ membranes were prepared by electroless plating after the SnCl₂-PdCl₂ process. The amount of Sn residue was adjusted by the SnCl₂ concentration, activation times and additional Sn(OH)₂ coating. The surface morphology, cross-sectional structure and elemental composition were analyzed by scanning electron microscopy (SEM), metallography and energy dispersive spectroscopy (EDS), respectively. Hydrogen permeation stability of the prepared palladium membranes were tested at 450-600℃ for 400 h. It was found that the higher SnCl₂ concentration and activation times enlarged the Sn residue amount and led to a lower initial selectivity but a better membrane stability. Moreover, the additional Sn(OH)₂ coating on the Al₂O₃ substrate surface also greatly improved the membrane selectivity and stability. Therefore, it can be concluded that the Sn residue from the SnCl₂-PdCl₂ process cannot be a main factor for the stability of the composite palladium membranes at high temperatures.

Heavy metal removal from water is a great concern for environmentalists and engineers. Ion-imprinted membranes are among the state of the art technologies for selective adsorption of heavy metals from aqueous environment. Dialysis permeation of nickel ions through Ni(II)-imprinted membranes has been thermodynamically studied in our prior work. In current study, the diffusive transport model was developed and then applied for better insight into the retardation mechanisms involved in the ion-imprinted membrane transport. The Sips isotherm model was coupled with the transport model to obtain the governing equation. Chemisorption and physical interactions (bulk diffusion and pore-clogging) were the most probable retardation mechanisms according to the modeling results. Relative retardation factor (η) was also defined as; transport-rate controlled by chemical adsorption to that controlled by physical interactions. With the help of the retardation factor, it was understood that the membrane behavior gradually changes from chemisorption to facilitated transport during permeation time. Effect of important operating parameters such as time, temperature and concentration on transport behavior was also investigated. Results indicated that chemisorption rate is rather higher at lower concentrations, early permeation times and reduced temperatures. In addition, η tabulated greater values for Ni(II) compared to Co(II) due to the imprinting effect.

The effects of N-methylimidazole cation[C_nmim] with different alkyl chain lengths, the types of cations and anions of ionic liquids and the reaction parameters on the catalytic activity and the selectivity for 4,4'-bisphenol F were investigated. The hydrogen bonding between the hydroxyl of phenol and the C2-position hydrogen of imidazole moiety in hydrophilic imidazole-based ionic liquid has important influence on the selectivity for 4,4'-bisphenol F, and under the conditions of the molar ratio of phenol/[C₄mim] [HSO₄] 1:1, reaction temperature 65℃ and the theoretical molar ratio of phenol/formaldehyde 2:1, the selectivity for 4,4'-bisphenol F reached 69.1%. Compared with the high phenol/formaldehyde ratio reported in literatures, the low molar ratio of phenol/formaldehyde and the low reaction temperature can greatly reduce energy consumption, and has important significance for industrial application.

A Cu-Fe-La/γ-Al₂O₃ (CFLA) catalyst was prepared by the excessive impregnation method and characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The results indicate that the catalyst contained mostly Cu²⁺, Fe³⁺, and La³⁺ and a small amount of Cu⁺, Fe²⁺, and La. The active components were uniformly distributed in the catalyst, and the particle size of the components was approximately 7.5 nm. The CFLA catalyst was used for the treatment of methyl orange (MO) solution by catalytic wet air oxidation (CWAO), and it exhibited a high catalytic activity. The catalytic reaction involved variable valence states of metals and free-radical reaction mechanism. The CWAO reaction of MO solution was fitted by a segmented first-order dynamic model, and the rapid reaction apparent activation energy was 13.9 kJ·mol^-1.

Biodiesel was produced at small scale by transesterification of used frying oil (UFO) recovered from Moroccan pastry shops and fish frying restaurants. Biodiesel was first synthesised at laboratory scale in order to optimize the transesterification parameters. The cost of the final product was also optimized using low-cost rawmaterials. The UFO and the produced biodiesel were characterized with several techniques including gas chromatography, ¹H NMR, ¹³C NMR, FTIR, and TGA-TDA techniques. ¹H NMR gas chromatographic analyses of the final product confirmed that the transesterification in the chosen experimental conditions was completed. These results were confirmed by TGA-TDA analysis used as new techniques to monitoring triglyceride conversion. The biodiesel did not contain any trace of glycerol, and it did meet the international standards. The transesterification at low cost in small scale conditions was performed at 60℃ using 1.2% of KOH and a methanol/oil molar ratio of 6:1. A yield of 80.8% was achieved. The properties of the produced biodiesel were found to be as good as those of biodiesels obeying to European standards. The biodiesel production was also performed at small-scale for individual utilisation. Thus, the product was tested in a kerosene stove for heating and non-modified commercial diesel engine producing electricity.

A series of CuO/ZnO/Al₂O₃, CuO/ZnO/ZrO₂/Al₂O₃ and CuO/ZnO/CeO₂/Al₂O₃ catalysts were prepared by coprecipitation and characterized by N₂ adsorption, XRD, TPR, N₂O titration and HRTEM. The catalytic performances of these catalysts for the steam reforming of methanol were evaluated in a laboratory-scale fixed-bed reactor at 0.1 MPa and temperatures between 473 and 543 K. The results showed that the catalytic activity depended greatly on the catalyst reducibility and the specific surface area of Cu. An approximate linear correlation between the catalytic activity and the Cu surface area was found for all catalysts investigated in this study. Compared to CuO/ZnO/Al₂O₃, the ZrO₂-doped CuO/ZnO/Al₂O₃ exhibited higher activity and selectivity to CO, while the CeO₂-doped catalyst displayed lower activity and selectivity. Finally, an intrinsic kinetic study was carried out over a screened CuO/ZnO/CeO₂/Al₂O₃ catalyst in the absence of internal and external mass transfer effects. A good agreement was observed between the model-derived effluent concentrations of CO (CO₂) and the experimental data. The activation energies for the reactions of methanol-steam reforming, water-gas shift and methanol decomposition over CuO/ZnO/CeO₂/Al₂O₃ were 93.1, 85.1 and 116.5 kJ·mol^-1, respectively.

Ni supported on bentonite was prepared by the impregnation method with different nickel contents, applied to the hydrogenation of nitrobenzene to aniline in a fixed-bed reactor, and it was characterized by X-ray diffraction (XRD), H₂-temperature programmed reduction (H₂-TPR), and X-ray photoelectron spectrometry (XPS). The results showed that Ni/bentonite catalyst with 20 wt% nickel content provided a higher conversion of nitrobenzene and selectivity of aniline compared to other catalysts. NiO was the precursor of the active component of the catalyst, and the small crystallite size as well as the highly dispersed NiO on the Ni/bentonite-20 catalyst, contributed to the catalytic performance. The hydrogenation of nitrobenzene was carried out at 300℃ with a H₂ gaseous hourly space velocity of 4800 ml·(g cat)^-1·h^-1 and a nitrobenzene liquid hourly space velocity of 4.8 ml·(g cat)^-1·h^-1 over Ni/bentonite-20. A 95.7% nitrobenzene conversion and 98.8% aniline selectivity were obtained.While the nitrobenzene liquid hourly space velocity was 4.8 ml·(g cat)^-1·h^-1, the yield of aniline was more than 95.0% during a 10-hour reaction.

The current study presents an effective method of determining and optimizing distillated methanol alternative arrangements. To complement the information required to run the rigorous simulation, V_min method is used as a base for the selection of the optimum arrangement among different alternatives. Results obtained from V_min diagram and shortcut simulation are utilized, by means of the simulator, for the precise simulation of alternative arrangements of methanol distillation under optimum conditions. Taking into account target function profit and the process parameters and conditions, the most optimum parameter value for reaching maximum profit was obtained, based on which all the arrangements with or without their heat integration were compared to each other. Technical and economic analysis results indicate, that increased profit by Prefractionator with heat integration arrangement is 4.79% compared to the base arrangement, while the three-column, four-column and five-column arrangements have benefits increase by 3.61%, 3.55% and 3.46%, respectively.

In our previous work, the reactive dividing wall column (RDWC) was proposed and proved to be effective for selective hydrogenation and separation of C3 stream. In the present paper, the dynamics and control of the proposed RDWC are investigated. Four control structures including composition and temperature controls are proposed. The feed forward controllers are employed in the four control strategies to shorten the dynamic response time, reduce the maximum deviations and offer an immediate adjustment. The control structures are compared by applying them into the RDWC system with 20% disturbances in both the feed flow rate and the feed compositions, and the results are discussed.

Based on stochastic optimization strategy, a formulation methodology is proposed for synthesizing distillation column sequences, allowing more than one middle component as the distributing components between a pair of key components in the non-sharp split. In order to represent and manipulate the distillation configuration structures, a new coding procedure is proposed in the form of one-dimensional array. Theoretically, an array can represent any kind of split (non-sharp and sharp).With the application of a binary sort tree approach, a robust flow sheet encoding and decoding procedure is developed so that the problem formulation and solution becomes tractable. In this paper, the synthesis problem is formulated as a mixed-integer nonlinear programming (MINLP) problem and an improved simulated annealing approach is adopted to solve the optimization problem. Besides, a shortcut method is applied to the evaluation of all required design parameters as well as the total function.

To explore the effect of removing different impurities to hydrogen networks, an MINLP model is proposed with all matching possibilities and the trade-off between operation cost and capital cost is considered. Furthermore, the impurity remover, hydrogen distribution, compressor and pipe setting are included in the model. Based on this model, the impurity and source(s) that are in higher priority for impurity removal, the optimal targeted concentration, and the hydrogen network with the minimum annual cost can be identified. The efficiency of the proposed model is verified by a case study.

An improved nonlinear adaptive switching control method is presented to relax the assumption on the higher order nonlinear terms of a class of discrete-time non-affine nonlinear systems. The proposed control strategy is composed of a linear adaptive controller, a neural network (NN) based nonlinear adaptive controller and a switching mechanism. An incremental model is derived to represent the considered system and an improved robust adaptive law is chosen to update the parameters of the linear adaptive controller. A new performance criterion of the switching mechanism is designed to select the proper controller. Using this control scheme, all the signals in the system are proved to be bounded. Numerical examples verify the effectiveness of the proposed algorithm.

Co-cracking is a process where the mixtures of different hydrocarbon feed stocks are cracked in a steam pyrolysis furnace, and widely adopted in chemical industries. In this work, the simulations of the co-cracking of ethane and propane, and LPG and naphtha mixtures have been conducted, and the software packages of COILSIM1D and SimCO are used to account for the cracking process in a tube reactor. The effects of the mixing ratio, coil outlet temperature, and pressure on cracking performance have been discussed in detail. The co-cracking of ethane and propane mixture leads to a lower profitability than the cracking of single ethane or single propane. For naphtha, cracking with LPG leads to a higher profitability than single cracking of naphtha, and more LPG can produce a higher profitability.

A metagenomic library recombinant clone CAPL3, an Escherichia coli strain generated by transformed with metagenomic library from deep-sea sediments, can efficiently produce cold active lipase. The effects of both temperature and dissolved oxygen (DO) on cold active lipase production by batch culture of metagenomic library recombinant clone (CAPL3) from deep-sea sediment were investigated. First, a two-stage temperature control strategy was developed, in which the temperature was kept at 34℃ for the first 15 h, and then switched to 30℃. The cold active lipase activity and productivity reached 315.2 U·ml^-1 and 8.08 U·ml^-1·h^-1, respectively, increased by both 14.5% compared to the results obtained with temperature controlled at 30℃. In addition, different DO control modes were conducted, based on the data obtained from the different DO control strategies and analysis of kinetics parameters at different DO levels. A step-wise temperature and DO control strategy were developed to improve lipase production, i.e., temperature and DO level were controlled at 34℃, 30% during 0-15 h; 30℃, 30% during 15-18 h, and 30℃, 20% during 18-39 h. With this strategy, the maximum lipase activity reached 354.6 U·ml^-1 at 39 h, which was 28.8% higher than that achieved without temperature and DO control (275.3 U·ml^-1).

Polyvinylpyrrolidone K-30 (PVP) was introduced into the preparation of nanozero-valent iron (nZVI) and the traditional liquid-phase reduction was improved. The introduction of PVP simplified the traditional method. The nZVI prepared with this new approach showed excellent surface characters and high performance on the removal of cadmium. TEM results showed that the aggregates of nZVI can reach to several micrometers in length but less than 100 nm in diameter. The iron particles that were enclosed by a layer of oxide film that is less than 10 nm, demonstrated that the nZVI possesses a core-shell structure. BET results indicate that the specific surface area of the nZVI was 20.3159m² g^-1. A three factor and three level orthogonal experiment was employed to find out the dominant factor that affects the removal rate of cadmium by nZVI. Based on the range values, the prominence order of each factor was:initial pH of the solution N initial concentration of cadmium N dosage of nZVI, the range was 96.453, 3.294 and 1.747, respectively. A simulation was performed under the same condition and a same conclusion was derived, this consistence confirmed the validity of the conclusion that pH is the most significant factor that affects the adsorption efficiency.

The adsorption behavior of CO₂, CH₄ and their mixtures in bituminous coal was investigated in this study. First, a bituminous coal model was built through molecular dynamic (MD) simulations, and it was confirmed to be reasonable by comparing the simulated results with the experimental data. Grand Canonical Monte Carlo (GCMC) simulations were then carried out to investigate the single and binary component adsorption of CO₂ and CH₄ with the built bituminous coal model. For the single component adsorption, the isosteric heat of CO₂ adsorption is greater than that of CH₄ adsorption. CO₂ also exhibits stronger electrostatic interactions with the heteroatom groups in the bituminous coal model compared with CH₄, which can account for the larger adsorption capacity of CO₂ in the bituminous coal model. In the case of binary adsorption of CO₂ and CH₄ mixtures, CO₂ exhibits the preferential adsorption compared with CH₄ under the studied conditions. The adsorption selectivity of CO₂ exhibited obvious change with increasing pressure. At lower pressure, the adsorption selectivity of CO₂ shows a rapid decrease with increasing the temperature, whereas it becomes insensitive to temperature at higher pressure. Additionally, the adsorption selectivity of CO₂ decreases gradually with the increase of the bulk CO₂ mole fraction and the depth of CO₂ injection site.

Limestone can be used for CO₂ capture and sequestration (CCS) in flue gas effectively. However, its CCS capability will dramatically decline after several cycles due to the surface "sintering". In this work, the limestone was modified with palygorskite to reduce sintering phenomenon between the absorbent particles during the CCS process and the carbonation rate of the limestone can be enhanced effectively. Palygorskite is a natural mineral with nano-fibrous structure which can reduce the mutual contact of limestone particles during the CCS process. The results were detected by TGA, SEM,MIP, FTIR and particle size analyzer respectively. The best CO₂ capture performance of modified absorbent was 13.11% improvement with only 5 wt% palygorskite added during the CCS process after 15 cycles compared with natural absorbent. It was found that excellent microscopic structures of absorbent modified with palygorskite was created, and the surface sintering was postponed leading to CO₂ capture performance enhanced under the same conditions.

Poly(m-xylylene adipamide)/poly(ethylene terephthalate) (MXD6/PET) copolymers are synthesized by melt copolycondensation with 1-5 wt% low molecular weight PET oligomers into the MXD6 oligomers at 260℃. FR-IR and ¹H NMR analysis results indicate that the interchange reaction has occurred between MXD6 oligomers and PET oligomers. The thermal behavior of copolymers shows that the melting temperature of MXD6/PET copolymers decreases with the increasing of amount of PET oligomers, while the crystallization temperature accordingly increases. And the equilibrium temperature T_m⁰ is evaluated to be 251.8℃ for the copolymers with 5 wt% PET oligomer adding, which is very close to that of neat MXD6. The tensile and impact strength of MXD6/PET copolymers are significantly improved than that of pure MXD6 by mechanical properties test, and the microfibril structure in the impact fracture sample's surface reveals the feature of ductile fracture.

The distribution of water channels in the crystal morphology of type-α hemi-hydrated gypsum (α-HH) was theoretically detected to investigate the effect of water channels on the hydration reactivity of hemi-hydrate phosphogypsum (HPG). Results showed that water channels were mainly distributed in the cylinders of α-HH crystal, whereas no water channel existed in the conical surfaces parallel to the z-axis. Increasing the number of water channels was critical to enhance the hydration activity of HPG compared with the hydration reactivity of industrial HPG and type-α high-strength gypsum. Controlling the technological parameters of crystallization by concentration of liquid-phase SO₄^2- made it possible to obtain HPG which had the stumpy crystals of α-HH and high hydration reactivity.

Hydrophobic Mg(OH)₂ nanoparticles were successfully synthesized via an in situ surface modification method in a novel impinging stream-rotating packed bed (IS-RPB) reactor using oleic acid (C₁₇H₃₃COOH, OA) as a surface modifier, magnesium chloride hexahydrate in the presence of ethanol as a precursor, and sodium hydroxide as a precipitant. The products were characterized by Fourier transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and thermogravimetry-differential scanning calorimetry (TG-DSC). Compatibility with organic solutions was determined by sedimentation tests. The prepared nanoparticles exhibited regular hexagonal lamella with an average diameter of 30 nm when OA is added to the reaction system; this result indicates that OA regulates the morphology of the Mg(OH)₂ nanoparticles. XRD revealed that the high-purityMg(OH)₂ product presents a brucite structure, and the I001/I101 of hydrophobic Mg(OH)₂ (0.86) was higher than that of the blank Mg(OH)₂ (0.63). FTIR analysis showed that OA bonded to the surface of the Mg(OH)₂. Comparedwith the blankMg(OH)₂ product, the product obtained through the proposed method possesses excellent hydrophobic properties, including a high water contact angle of 101.4° and good compatibility with liquid paraffin. TG-DSC analysis indicated that the total percentage of mass loss of hydrophobic Mg(OH)₂ (40.88%) was higher than that of the blank Mg(OH)₂ product (33.18%). The in situ surface modification method proposed in this work presents potential use in the large-scale production of Mg(OH)₂ nanoparticles.