The paper presents an experimental study on the heat transfer and flow friction characteristics in a solar air heater channel fitted with delta-winglet type vortex generators (DWs). The experiments are conducted by varying the airflow rate for Reynolds number in the range of 5000 to 24000 in the test section with a uniform heat-flux applied on the upper channel wall. Firstly, the DW pairs are mounted only at the entrance of the lower wall of the test channel (called DW-E) to create multiple vortex flows at the entry. The effect of two transverse pitches (R_P=P_t/H=1 and 2) at three attack angles (α=30°, 45° and 60°) of the DW-E with its relative height, b/H=0.5 (half height of channel) is examined. Secondly, the 30° DWs with three different relative heights (b/H 0.3, 0.4 and 0.5) are placed on the upper wall only (absorber plate, called DW-A) of the test channel. The experimental result reveals that in the first case, the 60° DW-E at R_P=1 provides the highest heat transfer and friction factor while the 30° DW-E at R_P=1 performs overall better than the others. In the second case, the 30° DW-A at b/H=0.5 yields the highest heat transfer and friction factor but the best thermal performance is found at b/H=0.4.

Affinity membranes are fabricated for boric acid removal by the surface functionalization of microporous polypropylene membrane (MPPM) with lactose-based polyols. The affinity is based on specific complexation between boric acid and saccharide polyols. A photoinduced grafting-chemical reaction sequence was used to prepare these affinity membranes. Poly(2-aminoethyl methacrylate hydrochloride) [poly(AEMA)] was grafted on the surfaces of MPPM by UV-induced graft polymerization. Grafting in the membrane pores was visualized by dying the cross-section of poly(AEMA)-grafted MPPM with fluorescein disodium and imaging with confocal laser scanning microscopy. It is concluded that lactose ligands can be covalently immobilized on the external surface and in the pores by the subsequent coupling of poly(AEMA) with lactobionic acid (LA). Physical and chemical properties of the affinity membranes were characterized by field emission scanning electron microscopy and Fourier Transform Infrared/Attenuated Total Refraction spectroscopy (FT-IR/ATR). 3-Aminophenyl boric acid (3-APBA) was removed from aqueous solution by a single piece of lactose-functionalized MPPM in a dynamic filtration system. The results show that the 3-APBA removal reaches an optimal efficiency (39.5%) under the alkaline condition (pH 9.1), which can be improved by increasing the immobilization density of LA. Regeneration of these affinity membranes can be easily realized through acid-base washing because the complexation of boric acid and saccharide polyol is reversible.

The interfacial compatibility of composite membrane is an important factor to its structural stability and separation performance. In this study, poly (ether sulfone) (PES) support layer was first hydrophilically modified with poly(vinyl alcohol) (PVA) via surface segregation during the phase inversion process. Gelatin (GE) was then cast on the PVA-modified PES support layer as the active layer followed by crosslinking to fabricate composite membranes for ethanol dehydration. The enrichment of PVA on the surface of support layer improved interfacial compatibility of the as-prepared GE/PVA-PES composite membrane. The water contact angle measurement and X-ray photoelectron spectroscopy (XPS) data confirmed the surface segregation of PVA with a surface coverage density of ~80%. T-peel test showed that the maximal force to separate the support layer and the active layer was enhanced by 3 times compared with the GE/PES membrane. The effects of PVA content in the support layer, crosslinking of GE active layer and operating parameters on the pervaporative dehydration performance were investigated. The operational stability of the composite membrane was tested by immersing the membrane in ethanol aqueous solution for a period of time. Stable pervaporation performance for dehydration of 90% ethanol solution was obtained for GE/PVA-PES membrane with a separation factor of ~60 and a permeation flux of ~1910 g·m^-2·h^-1 without peeling over 28 days immersion.

The nature of support and type of active metal affect catalytic performance. In this work, the effect of using La₂O₃ as promoter and support for Ni/γ-Al₂O₃ catalysts in dry reforming of methane was investigated. The reforming reactions were carried out at atmospheric pressure in the temperature range of 500-700℃. The activity and stability of the catalyst, carbon formation, and syngas (H₂/CO) ratio were determined. Various techniques were applied for characterization of both fresh and used catalysts. Addition of La₂O₃ to the catalyst matrix improved the dispersion of Ni and adsorption of CO₂, thus its activity and stability enhanced.

The functional materials based on natural zeolite (clinoptilolite), TiO₂-zeolite and Ag-TiO₂-zeolite have been successfully synthesized by solid-state reaction in fast-hydrothermal conditions. The obtained functional materials were investigated by X-ray diffraction (XRD), FT-IR (Fourier transform infrared) spectroscopy, DRUV-VIS (diffuse reflectance ultraviolet-visible) spectroscopy, BET (Brunauer-Emmett-Teller) and SEM/EDX (scanning electron microscope/energy dispersive X-ray spectrometer) analyses. The XRD results indicated that the clinoptilolite structure has a good thermal stabilization after the fast-hydrothermal treatment. Also, the high specific surface area about 92.55 m²·g^-1 was noticed for Ag-TiO₂-zeolite functional material. The presence of dopants was evidenced from EDX spectra. The enhanced bactericidal activity of Ag-TiO₂-zeolite catalyst is proved through damaging of Enterococcus faecalis colonies under visible irradiation, at different material doses and irradiation times.

A mathematical model for extraction of red pepper seed oil with supercritical CO₂ was proposed. Some factors influencing the process were investigated, including operation pressure, temperature and extraction yield X_e (%). The model was solved by the method of weighted residuals and used to simulate the process numerically. The kinetic equation is expressed as X_e=-16.8606exp(-t/9.98177)+16.95457 and the simulation results are in excellent agreement with the experimental data. The optimal operating parameters are 30 MPa, 318 K and 60 min.

Operation optimization is an effective method to explore potential economic benefits for existing plants. The maximum potential benefit from operation optimization is determined by the distances between current operating point and process constraints, which is related to the margins of design variables. Because of various disturbances in chemical processes, some distances must be reserved for fluctuations of process variables and the optimum operating point is not on some process constraints. Thus the benefit of steady-state optimization can not be fully achieved while that of dynamic optimization can be really achieved. In this study, the steady-state optimization and dynamic optimization are used, and the potential benefit is divided into achievable benefit for profit and unachievable benefit for control. The fluid catalytic cracking unit (FCCU) is used for case study. With the analysis on how the margins of design variables influence the economic benefit and control performance, the bottlenecks of process design are found and appropriate control structure can be selected.

Industrial processes are mostly large-scale systems with high order. They use fully centralized control strategy, the parameters of which are difficult to tune. In the design of large-scale systems, the decomposition according to the interaction between input and output variables is the first step and the basis for the selection of control structure. In this paper, the decomposition principle of processes in large-scale systems is proposed for the design of control structure. A new variable pairing method is presented, considering the steady-state information and dynamic response of large-scale system. By selecting threshold values, the related matrix can be transformed into the adjoining matrixes, which directly measure the couple among different loops. The optimal number of controllers can be obtained after decomposing the large-scale system. A practical example is used to demonstrate the validity and feasibility of the proposed interaction decomposition principle in process large-scale systems.

On the basis of reported experimental vapor-liquid equilibrium (VLE) data of NH₃-1-ethyl-3-methylimidazolium acetate (NH₃-[Emim]Ac), NH₃-1-butyl-3-methylimidazolium tetrafluoroborate (NH₃-[Bmim][BF₄]), NH₃-1,3-dimethylimidazolium dimethyl phosphate (NH₃-[Mmim]DMP) and NH₃-1-ethyl-3-methylimidazolium ethylsulfate (NH₃-[Emim]EtOSO₃) binary systems, the interaction parameters of 14 new groups have been regressed by means of the UNIFAC model. To validate the reliability of the method, these parameters have been used to calculate the VLE data with the average relative deviation of pressures of less than 9.35%. The infinite dilution activity coefficient (γ₁^∞) and the absorption potential (Ψ₁) are important evaluation criterions of the affinity between working pair species of the absorption cycle. The UNIFAC model is implemented to predict the values of γ₁^∞ and Ψ₁ of 16 sets of NH₃-ionic liquid (IL) systems. The work found that the Ψ₁ gradually increases following the impact order: Ψ₁([C_nmim][BF₄])<Ψ₁([C_nmim]EtOSO₃)<Ψ₁([C_nmim]DMP)<Ψ₁([C_nmim]Ac) (n=1, 2, 3,...) at a given cation of IL species and constant temperature, and <Ψ₁([Mmim]X)<Ψ₁([Emim]X)<Ψ₁([Pmim]X)<Ψ₁([Bmim]X) (X=Ac, [BF₄], DMP or EtOSO₃) at a given anion of IL species and constant temperature. Furthermore, the Ψ₁ gradually increases with increasing temperature. Then, it could be concluded that the working pair NH₃-[Bmim]Ac has the best potential research value relatively.

Static dielectric constant is a key parameter to estimate the electro-viscous effect which plays important roles in the flow and convective heat transfer of fluids with ions in microfluidic devices such as micro reactors and heat exchangers. A group contribution method based on 27 groups is developed for the correlation of static dielectric constant of ionic liquids in this paper. The ionic liquids considered include imidazolium, pyridinium, pyrrolidinium, alkylammonium, alkylsulfonium, morpholinium and piperidinium cations and various anions. The data collected cover the temperature ranges of 278.15-343.15 K and static dielectric constant ranges of 9.4-85.6. The results of the method show a satisfactory agreement with the literature data with an average absolute relative deviation of 7.41%, which is generally of the same order of the experimental data accuracy. The method proposed in this paper provides a simple but reliable approach for the prediction of static dielectric constant of ionic liquids at different temperatures.

Acetic acid was selected as the model compound representing the carboxylic acids present in bio-oil. This work focuses the co-cracking of acetic acid with ethanol for bio-gasoline production. The influences of reaction temperature and pressure on the conversion of reactants as well as the selectivity and composition of the crude gasoline phase were investigated. It was found that increasing reaction temperature benefited the conversion of reactants and pressurized cracking produced a higher crude gasoline yield. At 400℃ and 1 MPa, the conversion of the reactants reached over 99% and the selectivity of the gasoline phase reached 42.79% (by mass). The gasoline phase shows outstanding quality, with a hydrocarbon content of 100%.

Gliding arc gas discharge plasma was used for the generation of hydrogen from steam reforming of dimethyl ether (DME). A systemic procedure was employed to determine the suitable experimental conditions. It was found that DME conversion first increased up to the maximum and then decreased slightly with the increase of added water and air. The increase of total feed gas flow rate resulted in the decrease of DME conversion and hydrogen yield, but hydrogen energy consumption dropped down to the lowest as total feed gas flow rate increased to 76 ml·min^-1. Larger electrode gap and higher discharge voltage were advantageous. Electrode shape had an important effect on the conversion of DME and production of H₂. Among the five electrodes, electrode 2^# with valid length of 55 mm and the radian of 34 degrees of the top electrode section was the best option, which enhanced obviously the conversion of DME.

Membrane filtration technology combined with coagulation is widely used to purify river water. In this study, microfiltration (MF) and ultrafiltration (UF) ceramic membranes were combined with coagulation to treat local river water located at Xinghua, Jiangsu province, China. The operation parameters, fouling mechanism and pilot-scale tests were investigated. The results show that the pore size of membrane has small effect on the pseudo-steady flux for dead-end filtration, and the increase of flux in MF process is more than that in UF process for cross-flow filtration with the same increase of cross-flow velocity. The membrane pore size has little influence on the water quality. The analysis on membrane fouling mechanism shows that the cake filtration has significant influence on the pseudo-steady flux and water quality for the membrane with pore size of 50, 200 and 500 nm. For the membrane with pore size of 200 nm and backwashing employed in our pilot study, a constant flux of 150 L·m^-2·h^-1 was reached during stable operation, with the removal efficiency of turbidity, total organic carbon (TOC) and UV254 higher than 99%, 45% and 48%, respectively. The study demonstrates that coagulation-porous ceramic membrane hybrid process is a reliable method for river water purification.

Various conditions were investigated in detail for the novel organic template-free static hydrothermal synthesis of SUZ-4 zeolite in the presence of seeds. The obtained samples were characterized by XRD (X-ray diffraction), SEM (scanning electron microscope), TG (thermal gravimetric analysis), ICP (inductively coupling plasma) elemental analysis, nitrogen sorption isotherm and surface area. The results show that pure SUZ-4 zeolites with high crystallinity are obtained in a broad window of synthesis conditions: seed mass concentration 0.2%-2%, SiO₂/Al₂O₃ molar ratio 21-25, KOH/SiO₂ molar ratio 0.33-0.43, H₂O/SiO₂ molar ratio 7.14-38.1, aging time 24 h, crystallization temperature 160℃, and crystallization time 6-10 d. Also, crystallinity and size of the rod-like SUZ-4 zeolite crystals are found to alter with the conditions.