The study is focused on modeling of separation process and optimization.An adsorption separation process is simulated.The surfactin production process by Bacillus subtilis ATCC 21332 followed by surfactin adsorption in a fixed-bed column packed with commercial active carbon is studied in laboratory.The adsorption column achieves high surfactin recovery(94%)by up-flow methanol elution at 25℃.The adsorption column is simulated with a complex one-dimensional plug flow dispersion model coupled with nonlinear adsorption equilibrium,based on the assumption that the adsorption of surfactin is monomolecular layer and no micelle is formed.The molecular diffusion coefficient of surfactin in water solution with electric neutrality is estimated to be 0.428×10^-5cm²·s^-1 by molecular dynamics simulation.The model developed can describe the complex interplay of adsorption kinetics,fluid dynamics,and mass-transfer phenomena based on the assumption of no radial temperature and concentration gradients,and is of adequate precision.The work involved in this paper is valuable for the optimization of the production process of surfactin.

Lanthanum alginate bead is a new, highly active adsorbent. In the present study, we investigated its adsorption performance and its adsorption mechanism. The adsorption isotherm for fluoride onto lanthanum alginate b ead fits the Langmuir model well, and the maximum adsorption capacity is 197.2 mg·g^-1. X-ray diffraction shows the amorphous nature of lanthanum alginate bead, which allows for better accessibility to fluoride and thus better activity. Infrared spectra of lanthanum alginate bead before and after adsorption confirm its stable skeletal structure. Scanning electron microscopy shows that the dense surface structure of the adsorbent appear cracks after adsorption. T he adsorption mechanism of lanthanum alginate bead is considered as an ion exchange between F^- and Cl^- or OH^-, as verified from the adsorbent and the solution by pH effect, energy dispersive X-ray, and ion chromatography.

Butyl-levulinate has been identified as a promising fuel candidate with high oxygen content. Its combustion in diesel engines yields very low soot and NO_x emissions. It can be produced by the esterification of butanol and levulinic acid, which themselves are platform chemicals in a biorenewables-based chemical supply chain. Since the equilibrium of esterification limits the conversion in a conventional reactor, reactive distillation can be applied to overcome this limitation. The presence of the high-boiling catalyst sulfuric acid requires a further separation step downstream of the reactive distillation column to recover the catalyst for recycle. Optimal design specifications and an optimal operating point are determined using rigorous flowsheet optimization. The challenging optimization problem is solved by a favorable initialization strategy and continuous reformulation. The design identified has the potential to produce a renewable transportation fuel at reasonable cost.

The feasibility and adsorption effect of lignite activated carbon for phenol removal from aqueous solutions were evaluated and investigated. A series of tests were performed to look into the influence of various experimental parameters such as contact time, initial phenol concentration, temperature, and pH value on the adsorption of phenol by lignite activated carbon. The experimental data were fitted well with the pseudo-second-order kinetic model. The adsorption is an endothermic process and conforms to Freundlich thermodynamic model. The results indicate that the lignite activated carbon is suitable to be used as an adsorbent material for adsorption of phenol from aqueous solutions.

Amine-functionalized mesoporous silica was prepared by using lauric acid and N-stearoyl-l-glutamic acid as structure directing agents via the S^-N⁺-I^- mechanism and applied to CO₂ adsorption at room temperature. With γ-aminopropyltriethoxysilane as co-structure directing agent and due to the direct electrostatic interaction with anionic surfactant, most of the amino groups were uniformly distributed at the inner surface of pores and the performance was stable. The amine-functionalized mesoporous silica was characterized by Fourier transform infrared spectrometer, X-ray diffraction, nitrogen physisorption and thermogravimetric analysis. The CO₂ adsorption capacity was measured by digital recording balance. At the room temperature and under the atmospheric pressure, the adsorption capacity of LAA-AMS-0.2 for CO₂ and N₂ is 1.40 mmol·g^-1 and 0.03 mmol·g^-1, respectively, indicating high separation coefficient of CO₂/N₂.

A group of Zn-Al layered double hydroxides(LDHs)were synthesized at different temperatures from 25-90℃ in order to investigate the influence of synthesis temperature on characteristics of the LDHs and their phosphate adsorption behaviour.The results reveal that an increase in the synthesis temperature generally improves the specific surface area of the sample and the phosphate adsorption capacity.The significantly enhanced crystallinity of the Zn-Al-30,synthesized at 30℃,leads to a remarkable decrease in the specific surface area and consequently a poor phosphate adsorption capacity.It is suggested that the surface adsorption plays an important role in the phosphate uptake by the Zn-Al LDHs.Zn-Al-70 presents a relatively higher crystallinity and a lower specific surface area,compared with Zn-Al-60 and Zn-Al-80,but the highest phosphate adsorption capacity,indicating that surface adsorption is only one of the pathways for phosphate removal.The phosphate adsorption by the Zn-Al follows a pseudo-second-order kinetic equation.The adsorption isotherms fit Langmuir models,and the maximum adsorption capacities of the Zn-Al-25,Zn-Al-50 and Zn-Al-70 are estimated to be 17.82,21.01 and 27.10 mg·g^-1 adsorbent,respectively.

This paper deals with the enantioseparation of phenylsuccinic acid(H₂A)enantiomers by liquid-liquid reactive extraction usingβ-CD derivatives as aqueous selectors.Cyclodextrin and its derivatives can interact with guest molecules selectively to form complexes with different stabilities.Cyclodextrin derivatives are not soluble in organic liquids,but highly soluble in water.In this work,hydroxypropyl-β-cyclodextrin(HP-β-CD),hydroxyethyl β-cyclodextrin(HE-β-CD)and methyl-β-cyclodextrin(Me-β-CD)were selected as chiral selectors in aqueous phase for the reactive extraction of phenylsuccinic acid enantiomers from organic phase to aqueous phase.The results show that the efficiency of the extraction depends,often strongly,on a number of process variables,including the types of organic solvents and β-CD derivatives,the concentrations of the extractants and H₂A enantiomers,pH and temperature.HP-β-CD,HE-β-CD and Me-β-CD have stronger recognition abilities for R-phenylsuccinic acid than for S-phenylsuccinic acid.Among the three kinds of β-CD derivatives,HP-β-CD has the strongest separation ability. Excellent enantioseparation was achieved under the optimal conditions of pH of 2.5 and temperature of 5℃ with a maximum enantioselectivity(a)of 2.38.Reactive extraction of enantiomers with hydrophilic β-CD derivatives is of strong chiral separation ability and can be hopeful for separations of various enantiomers at a large-scale.

This paper reports on a new microporous composite silica membrane prepared via acid-catalyzed polymeric route of sol-gel method with tetraethylorthosilicate(TEOS)and a bridged silsesquioxane[1,2-bis(triethoxysilyl)ethane, BTESE]as precursors.A stable nano-sized composite silica sol with a mean volume size of~5 nm was synthesized. A 150 nm-thick defect-free composite silica membrane was deposited on disk support consisting of macroporous α-Al₂O₃ and mesoporousγ-Al₂O₃ intermediate layer by using dip-coating approach,followed by calcination under pure nitrogen atmosphere.The composite silica membranes exhibit molecular sieve properties for small gases like H₂,CO₂,O₂,N₂,CH₄ and SF₆ with hydrogen permeances in the range of(1-4)×10^-7mol·m^-2·s^-1·Pa^-1 (measured at 200℃,3.0×10⁵Pa).With respect to the membrane calcined at 500℃,it is found that the permselectivities of H₂(0.289 nm)with respect to N₂(0.365 nm),CH₄(0.384 nm)and SF₆(0.55 nm)are 22.9,42 and>1000,respectively, which are all much higher than the corresponding Knudsen values(H₂/N₂=3.7,H₂/CH₄=2.8,and H₂/SF₆=8.5).

The convective heat transfer and friction behaviors of turbulent tube flow through a straight tape with double-sided delta wings(T-W)have been studied experimentally.In the current work,the T-W formed on the tape was used as vortex generators for enhancing the heat transfer coefficient by breakdown of thermal boundary layer and by mixing of fluid flow in tubes.The T-W characteristics are(1)T-W with forward/backward-wing arrangement,(2)T-W with alternate axis(T-WA),(3)three wing-width ratios and(4)wing-pitch ratios.The experimental result reveals that for using the T-W,the increases in the mean Nusselt number(Nu)and friction factor are,respectively,up to 165% and 14.8 times of the plain tube and the maximum thermal performance factor is 1.19.It is also obvious that the T-W with forward-wing gives higher heat transfer rate than one with backward-wing around 7%. The present investigation also shows that the heat transfer rate and friction factor obtained from the T-WA is higher than that from the T-W.In addition,the flow pattern and temperature fields in the T-W tube with both backward and forward wings were also examined numerically.

The partial oxidation of hydrocarbons is an important technical route to produce acetylene for chemical industry.The partial oxidation reactor is the key to high acetylene yields.This work is an experimental and numerical study on the use of a methane flame to produce acetylene.A lab scale partial oxidation reactor was used to produce ultra fuel-rich premixed jet flames.The axial temperature and species concentration profiles were measured for different equivalence ratios and preheating temperatures,and these were compared to numerical results from Computational Fluid Dynamics(CFD)simulations that used the Reynolds Averaged Navier-Stokes Probability Density Function(RANS-PDF)approach coupled with detailed chemical mechanisms.The Leeds 1.5,GRI 3.0 and San Diego mechanisms were used to investigate the effect of the detailed chemical mechanisms.The effects of equivalence ratio and preheating temperature on acetylene production were experimentally and numerically studied.The experimental validations indicated that the present numerical simulation provided reliable prediction on the partial oxidation of methane.Using this simulation method the optimal equivalence ratio for acetylene production was determined to be 3.6.Increasing preheating temperature improved acetylene production and shortened greatly the ignition delay time.So the increase of preheating temperature had to be limited to avoid uncontrolled ignition in the mixing chamber and the pyrolysis of methane in the preheater.

Amorphous Ni-B/ZrO₂ catalysts were prepared by coprecipitation-chemical reduction with KBH₄ aqueous solution,and various crystalline phase ZrO₂(amorphous-ZrO₂,tetragonal-ZrO₂ and monoclinic-ZrO₂) supported Ni-B catalysts were obtained by thermal treatment in 5%H₂-N₂ stream at different temperature.The effect of ZrO₂ polymorphs and the treatment temperature on the catalytic performance for the CO selective methanation were investigated,and the catalysts were characterized by N₂ physisorption,Powder X-ray diffraction(XRD), Temperature-Programmed Desorption(CO-TPD and H₂-TPD),and Differential Scanning Calorimeter(DSC).The treatment temperature affected strongly the crystalline structure of ZrO₂,and the CO methanation activity and selectivity of the Ni-B/ZrO₂ catalysts were significantly influenced by the crystalline phase of ZrO₂.Of the three forms of ZrO₂ polymorphs(amorphou-ZrO₂,tetragonal-ZrO₂ and monoclinic-ZrO₂),the amorphous-ZrO₂ supported nickle catalyst showed highest CO methanation activity,attributing in large part to the largest specific surface area and the optimum CO/H₂ absorption intensity of the Ni-B/amorphous-ZrO₂ catalyst.

Aromatization of methanol over co-impregnated La/Zn/HZSM-5 zeolite catalyst was studied.The selectivity of aromatics and BTX(benzene,toluene,and xylene)reached 64.0% and 56.6%,respectively,using La/Zn/HZSM-5 at 437℃,0.1 MPa and methanol WHSV(weight hourly space velocity)=0.8 h^-1.Catalytic results showed that the La species was a very good promoter,increased selectivity of aromatics,and prolonged the catalyst lifetime on stream.The effects of the SiO₂/Al₂O₃ ratio in zeolite,Zn and La loading,WHSV,reaction temperature, water content in the feed and H₂ pretreatment of catalysts on the catalytic performance were studied in detail. Characterizations of the catalysts by thermogravimetric analysis(TGA),NH₃-TPD(temperature programmed desorption),SEM(scanning electron micrograph),N₂ adsorption-desorption,XRD(X-ray diffraction) and XRF (X-ray fluorescence),were carried out to understand the structure and discuss the aromatization performance of La/Zn/HZSM-5 zeolite catalyst.

Highly efficient solvent-free coupling reaction of carbon dioxide(CO₂)and epichlorohydrin catalyzed by meso-tetraphenyl porphyrin magnesium(MgTPP)in the presence of triethylamine as co-catalysts is reported.As a chlorophyll-like catalyst,MgTPP showed excellent activity for the coupling reaction of CO₂ and epichlorohydrin to chloropropene carbonate,in which the turnover number could reach up to 9200.Moreover,different factors including the amount of catalyst,reaction temperature,pressure and time were systematically investigated and the optimal reaction conditions were obtained(epichlorohydrin 50 mmol,MgTPP 5.0×10^-3mmol,triethylamine 6.25×10^-3mmol,140℃,1.5 MPa,8 h).A plausible two-pathway mechanism for the coupling reaction of CO₂ and epichlorohydrin is proposed to propound the catalysis of MgTPP.

A novel process to recovery natural gas liquids from oil field associated gas with liquefied natural gas (LNG)cryogenic energy utilization is proposed.Compared to the current electric refrigeration process,the proposed process uses the cryogenic energy of LNG and saves 62.6%of electricity.The proposed process recovers ethane, liquid petroleum gas(propane and butane)and heavier hydrocarbons,with total recovery rate of natural gas liquids up to 96.8%.In this paper,exergy analysis and the energy utilization diagram method(EUD)are used to assess the new process and identify the key operation units with large exergy loss.The results show that exergy efficiency of the new process is 44.3%.Compared to the electric refrigeration process,exergy efficiency of the new process is improved by 16%.The proposed process has been applied and implemented in a conceptual design scheme of the cryogenic energy utilization for a 300 million tons/yr LNG receiving terminal in a northern Chinese harbor.

In industrial processes,there exist faults that have complex effect on process variables.Complex and simple faults are defined according to their effect dimensions.The conventional approaches based on structured residuals cannot isolate complex faults.This paper presents a multi-level strategy for complex fault isolation.An extraction procedure is employed to reduce the complex faults to simple ones and assign them to several levels.On each level,faults are isolated by their different responses in the structured residuals.Each residual is obtained insensitive to one fault but more sensitive to others.The faults on different levels are verified to have different residual responses and will not be confused.An entire incidence matrix containing residual response characteristics of all faults is obtained,based on which faults can be isolated.The proposed method is applied in the Tennessee Eastman process example,and the effectiveness and advantage are demonstrated.

In absorption cycles,ionic liquid(IL)1,3-dimethylimidazolium tetrafluoroborate([Dmim]BF₄)may be a promising absorbent of working pair using water as refrigerant.The vapor pressures of[Dmim]BF₄ aqueous solution were measured with the boiling-point method in the temperature range from 312.25 to 403.60 K and in the mass concentration range of 65% to 90% of[Dmim]BF₄.The experimental data were correlated with an Antoine-type equation and the Non-Random Two-Liquid(NRTL)model,and the average absolute deviations between the experimental and calculated values were 1.06% and 1.15%,respectively.For the[Dmim]BF₄ aqueous solution,the experimental vapor pressures show negative deviations from the calculated data with Raoult’s law.For higher mass concentration of the IL,the deviation is more negative.In addition,the vapor pressures,the hydrophilicity and the solubility of[Dmim]BF₄ aqueous solutions were compared with those of[Dmim]Cl aqueous solutions and [Bmim]BF₄ aqueous solutions at IL-mole fraction of 0.20.

The densities and viscosities of ternary systems(Poloxamer 188+ethanol/acetone+water)were measured at 288.15,293.15,298.15,303.15,308.15 K and atmospheric pressure for different mass fractions of Poloxamer 188(0 to 0.02)in aqueous solution and different solvent volume fractions of ethanol/acetone(0 to 0.3)in Poloxamer 188 aqueous solution.The densities were measured by a pycnometer,while the viscosities were measured using two Ubbelohde capillary viscometers.The correlations of density and viscosity of these ternary systems are obtained by fitting the experimental data at different temperatures,mass fractions and volume fractions.

Many by-products are generated in the process of oxidizing cyclohexene to produce 1,2-epoxycyclohexane by hydrogen peroxide,including cyclohexanol,cyclohexanone,etc.To obtain high-purity 1,2-epoxycyclohexane, the by-products and unreacted cyclohexene must be removed through rectification,in which the vapor-liquid equilibrium(VLE)data of the system are needed.In this study,the VLE data of cyclohexene-cyclohexanol system were studied at 101.3 kPa using an improved EC-2 VLE still.The thermodynamic consistency of the data was examined by Herington’s method.The results obtained were exemplary.The VLE data were correlated by the Wilson equation. The difference between the calculated values and the experimental data is minor,indicating that the VLE data are suitable for engineering design.

Calcium sulfoaluminate,3CaO·3Al₂O₃·CaSO₄,has been widely recognized in the realms of high-temperature combustion and cement chemistry.However,the lack of relevant thermodynamic data limits the progress of its research and development.Through comparative calculations using several different approaches,we obtain the thermochemical properties of 3CaO·3Al₂O₃·CaSO₄ in this work,such as its standard formation enthalpy,Gibbs free energy of formation,entropy,and molar heat capacity.With these fundamental data,thermodynamic calculations become possible for reactions involving this mineral.It is found that some reactions proposed in literature to generate this mineral may not proceed thermodynamically.

A statistical-mechanical-based equation of state(EOS)for pure substances,the Tao-Mason equation of state,is successfully extended to prediction of the(p-v-T)properties of fourteen natural gas mixtures at temperatures from 225 K to 483 K and pressures up to 60.5 MPa.This work shows that the Tao-Mason equation of state for multicomponent natural gas is predictable with minimal input information,namely critical temperature,critical pressure,and the Pitzer acentric factor.The calculated results agree well with the experimental data.From a total of 963 data of density and 330 data of compressibility factor for natural gases examined in this work,the average absolute deviations(AAD)are 1.704% and 1.344%,respectively.The present EOS is further assessed through the comparisons with Peng-Robinson(PR)equation of state.For the all of mixtures Tao-Mason(TM) EOS outperforms the PR EOS.

The polyphenol content,antioxidant and antimicrobial activities of the extracts obtained by classical, ultrasonic and Soxhlet extractions from dry aerial parts of two Artemisia species(Artemisia vulgaris and Artemisia campestris)were compared.Ultrasound positively affected the yield of extractive substance and the kinetics of extraction,but the extract obtained by the classical extraction showed the highest antioxidant activities and contained higher total contents of phenolic compounds and flavonoids than the extracts obtained by two other extraction techniques.Both flavonoid aglycones(apigenin,quercetin,quercetin 3,3′-dimethyl ether)and flavonoid glycosides(rutin,hyperoside and kaempferol 3-rhamnoside)were identified by thin layer chromatograph(TLC)analysis in the extracts from both species.A.campestris extracts were richer in quercetin than A.vulgaris and its antimicrobial activity was also better than A.vulgaris.Extracts obtained from both species were found to be more effective on the tested yeasts than bacteria.The kinetics of the total extractive substances,such as phenolic,flavonoids and quercetin extraction,was successfully described by the model of unsteady-state diffusion.

In this study,four sequencing batch reactors(SBR),with the sludge retention time(SRT)of 5,10,20 and 40 d,were used to treat domestic wastewater,and the effect of SRT on nitrite accumulation in the biological nitrogen removal SBR was investigated.The real-time control strategy based on online parameters,such as pH,dissolved oxygen(DO)and oxidation reduction potential(ORP),was used to regulate the nitrite accumulation in SBR. The model-based simulation and experimental results showed that with the increase of SRT,longer time was needed to achieve high level of nitritation.In addition,the nitrite accumulation rate(NAR)was higher when the SRT was relatively shorter during a 112-day operation.When the SRT was 5 d,the system was unstable with the mixed liquor suspended solids(MLSS)decreased day after day.When the SRT was 40 d,the nitrification process was significantly inhibited.SRT of 10 to 20 d was more suitable in this study.The real-time control strategy combined with SRT control in SBR is an effective method for biological nitrogen removal via nitrite from wastewater.

Removal of SO₂ and NO_x by pulsed corona combined with in situ alkali absorption was experimentally investigated.In the reactor,a plate-wire-plate combination is devised for generating pulsed corona and then alkaline absorbent slurries were introduced into the reactor by a continuous band conveying system to capture the gaseous reaction products.It was found that both SO₂ and NO could be removed by corona combined with in situ alkali absorption.The removal of SO₂ increased to 75% with the corona discharge,compared with 60% removal only with Ca(OH)₂ absorption.About 40% removal of NO was reached by pulsed corona combined with in situ Ca(OH)₂ absorption.It was found that SO₂ and NO in the gas stream are oxidized to SO₃ and NO₂ by pulsed corona respectively,and then absorbed by the alkali in the reactor.The removals of SO₂ as well as NO were higher with Ca(OH)₂ as the absorbent,compared with using CaCO₃ or ZnO.

The aroma sustained-release cotton fabric was prepared by finishing rose fragrance nanocapsules directly on cotton.The structure and properties of nanocapsules were demonstrated by transmission electron microscope(TEM),dynamic light scattering(DLS),fourier transform infrared spectrometer(FTIR),X-ray diffraction (XRD),gas chromatography-mass spectrometry(GC-MS)and electronic nose.The results showed that the spherical nanocapsule dispersed evenly and the average diameter kept 51.4 nm.The existence of —COO peak(1741 cm^-1)in the FTIR curve of the finished cotton fabric and the decrease of crystallinity demonstrated that rose fragrance nanocapsules have been incorporated into the cotton fabrics.The washing resistance of the cotton fabrics finished by 51.4 nm nanocapsules was much better than that by rose fragrance alone.Besides,the loss of fragrance from the cotton fabrics finished by 51.4 nm nanocapsules was obviously lower than that by 532 nm nanocapsules and rose fragrance.The smaller the nanocapsule size,the better the sustained release property.Electronic nose analysis also displayed that the aroma released from the cotton fabrics finished by nanocapsules after washing has no obvious variety in contrast to that without washing.The cotton fabrics finished by nanocapsules has the excellent sustained release property.

In order to address the bubble formation and movement in air-water two-phase flow,single bubble rising in stagnant water is experimentally studied by digital image processing.Bubbles are released individually from the submerged orifices with different diameters(1.81 mm,2.07 mm,2.98 mm,3.92 mm)at different detachment frequency.Images are recorded by a high-speed video camera and processed by digital image processing technique. The factors impacting the formed volume of bubble are discussed.The experimental results showed that a threshold of gas flow rate(400 mm³·s^-1)divides the bubble formation into two regimes:the constant volume regime and the growing volume regime.Especially for the growing volume regime,the surface tension is taken into account.The bubble volume is consisted of two parts:the surface tension impacting part and the gas volume flow rate impacting part.An improved correlation for bubble volume prediction is developed for the two regimes and better coincidence with the experiment data than the previous models is obtained.