Gas-liquid microreaction technology has shown great potential in a variety of industrial relevant mass transfer operations and reactions. This paper outlines the current research status of this technology with emphasis on reactor design, hydrodynamics and mass transfer phenomena as well as reaction applications. The future challenges of this important technology are also summarized.

Behavior of catalytic cracking reactions of particle cluster in fluid catalytic cracking (FCC) riser reactors was numerically analyzed using a four-lump mathematical model. Effects of the cluster porosity, inlet gas velocity and temperature, and coke deposition on cracking reactions of the cluster were investigated. Distributions of temperature, gases, and gasoline from both catalyst particle cluster and an isolated catalyst particle are presented. The reaction rates from vacuum gas oil (VGO) to gasoline, gas and coke of individual particle in the cluster are higher than those of the isolated particle, but it reverses for the reaction rates from gasoline to gas and coke. Less gasoline is produced by particle clustering. Simulated results show that the produced mass fluxes of gas and gasoline increase with the operating temperature and molar concentration of VGO, and decrease due to the formation of coke.

The second-order moment combustion model,proposed by the authors is validated using the direct numerical simulation(DNS)of incompressible turbulent reacting channel flows.The instantaneous DNS results show the near-wall strip structures of concentration and temperature fluctuations.The DNS statistical results give the budget of the terms in the correlation equations,showing that the production and dissipation terms are most important.The DNS statistical data are used to validate the closure model in RANS second-order moment(SOM) combustion model.It is found that the simulated diffusion and production terms are in agreement with the DNS data in most flow regions,except in the near-wall region,where the near-wall modification should be made,and the closure model for the dissipation term needs further improvement.The algebraic second-order moment(ASOM) combustion model is well validated by DNS.

Using the multiple reference frames(MRF)impeller method,the three-dimensional non-Newtonian flow field generated by a double helical ribbon(DHR)impeller has been simulated.The velocity field calculated by the numerical simulation was similar to the previous studies and the power constant agreed well with the experimental data.Three computational fluid dynamic(CFD)methods,labeled I,Ⅱ and Ⅲ,were used to compute the Metzner constant ks.The results showed that the calculated value from the slop method(method I)was consistent with the experimental data.Method II,which took the maximal circumference-average shear rate around the impeller as the effective shear rate to compute ks,also showed good agreement with the experiment.However,both methods suffer from the complexity of calculation procedures.A new method(method Ⅲ)was devised in this paper to use the area-weighted average viscosity around the impeller as the effective viscosity for calculating ks.Method Ⅲshowed both good accuracy and ease of use.

The flow fields in a dual Rushton impeller stirred tank with diameter of 0.48 m(T)were measured by using Particle Image Velocimetry(PIV).Three different size impellers were used in the experiments with diameters of D=0.33T,0.40T and 0.50T,respectively.The multi-block and 360°ensemble-averaged approaches were used to measure the radial and axial angle-resolved velocity distributions.Three typical flow patterns,named,merging flow,parallel flow and diverging flow,were obtained by changing the clearance of the bottom impeller above the tank base(C₁)and the spacing between the two impellers(C₂).The results show that while C₁ is equal to D,the parallel flow occurs as C₂≥0.40T,C₂≥0.38T and C₂≥0.32T and the merging flow occurs as C₂≤0.38T, C₂≤0.36T and C₂≤0.27T for the impellers with diameter of D=0.33T,0.40T and 0.50T,respectively.When C₂ is equal to D,the diverging flow occurs in the value of C₁≤0.15T for all three impellers.The flow numbers of these impellers were calculated for the parallel flow.Trailing vortices generated by the lower impeller for the diverging flow were shown by the 10°angleresolved velocity measurements.The peak value of turbulence kinetic energy (k/V_tip²=0.12-0.15 or above)appears along the center of the impeller discharging stream.

Particle Image Velocimetry(PIV)has been used to investigate turbulence characteristics in a 0.48 m diameter stirred vessel filled to a liquid height(H=1.4T)of 0.67 m.The agitator had dual Rushton impellers of 0.19 m diameter(D=0.4T).The developed flow patterns depend on the clearance of the lower impeller above the base of the vessel,the spacing between the two impellers,and the submergence of the upper impeller below the liquid surface.Their combinations can generate three basic flow patterns,named,parallel,merging and diverging flows.The results of velocity measurement show that the flow characteristics in the impeller jet flow region changes very little for different positions.Average velocity,trailing vortices and shear strain rate distributions for three flow patterns were measured by using PIV technique.The characteristics of trailing vortex and its trajectory were described in detail for those three flow patterns. Since the space-resolution of PIV can only reach the sub-grid rather than the Kolmogorov scale,a large-eddy PIV analysis has been used to estimate the distribution of the turbulent kinetic energy dissipation.Comparison of the distributions of turbulent kinetic energy and dissipation rate in merging flow shows that the highest turbulent kinetic energy and dissipation are both located in the vortex regions,but the maxima are at somewhat different locations behind the blade.About 37% of the total energy is dissipated in dual impeller jet flow regions.The obtained distribution of shear strain rate for merging flow is similar to that of turbulence dissipation,with the shear strain rate around the trailing vortices much higher than in other areas.

Diffusion of pure H₂,CO,N₂,O₂ and CH₄ gases through nanoporous carbon membrane is investigated by carrying out non-equilibrium molecular dynamics(NEMD)simulations.The flux,transport diffusivity and activation energy for the pure gases diffusing through carbon membranes with various pore widths were investigated. The simulation results reveal that transport diffusivity increases with temperature and pore width,and its values have a magnitude of 10^-7 m²·s^-1 for pore widths of about 0.80 to 1.21 nm at 273 to 300 K.The activation energies for the gases diffusion through the membrane with various pore widths are about 1-5 kJ·mol^-1.The results of transport diffusivities are comparable with that of Rao and Sircar(J.Membr.Sci.,1996),indicating the NEMD simulation method is a good tool for predicting the transport diffusivities for gases in porous materials,which is always difficult to be accurately measured by experiments.

Using pressure swing adsorption(PSA)technology to purify carbon monoxide(CO)discharged from industrial gases is a high-efficiency and economical method.In this article,a four-bed PSA experiment for CO purification was improved and optimized,in which a set of 120 m³·h^-1 pilot-scale PSA device was developed to purify CO from industrial tail gases,a set of control systems suitable for industry production was developed,and the influences of the operating parameters on CO purification were investigated.The experimental results indicated that the pilot-scale PSA device could produce qualified product gas and get high CO recovery ratio under optimized conditions.The research may provide reliable fundamental data,for industrial scale utilization of CO,from industrial tail gases,and have strong market competitive power and a broad promoted application prospect.

Distribution of TX114 between coacervate and aqueous phases in clouding of various initial TX114 concentrations was studied. Effects of temperature and salinity (Na₂SO₄) on the distribution of TX114 concentration were also investigated. Differing from the nonionic surfactant C₁₂E₁₀, the distribution of TX114 is sensitive to the temperature, and it is observed that the TX114 concentration in the aqueous phase (C_aq) does not depend on the initial TX114 concentration apparently at 45℃, and the C_aq decreases with an increase of Na₂SO₄ concentration.Low initial TX114 concentration in unclouded solutions, high Na₂SO₄ concentration, and temperature are suggested to control the surfactant loss in large-scale cloud point extraction applications.

The effect of steam dilution on the formation of coke and minor products in 2-methylpenatne cracking on ultra stable HY at 673 K has been studied. The results show that steam dilution suppresses the formation of coke and minor aromatic products, but enhances the H/C atomic ratio of coke and the production of diolefins. This and other evidences suggest that steam dilution enhances the desorption of coke precursors, diolefinic ions and cyclic ions, by inhibiting the further pathological reactions to produce aromatics and polyaromatics. These insights into the chemistry underlying coke formation in hydrocarbon cracking on solid acid catalysts can potentially be applied to the development of additives which inhibit coke formation and control catalyst deactivation. Keywords 2-methylpentane, catalytic cracking, coke formation, steam dilution, inhibition

Several MoS₂ catalysts of different structure,prepared by in situ decomposition of ammonium heptamolybdate(AHM)and molybdenum naphthenate(MoNaph),and by MoS₂ exfoliation(TDM),were characterized by BET, X-ray diffraction(XRD),Energy Dispersive X-ray(EDX)and transmission electron microscopy(TEM).The analysis showed that MoS₂ structure was dependant upon the preparation procedure.The activity of the catalysts was determined by measuring the hydrodeoxygenation(HDO)of phenol,4-methylphenol and 4-methoxyphenol using a batch autoclave reactor operated at 2.8 MPa of hydrogen and temperatures ranging from 320-370℃.By comparing the conversion,the reactivity order of the catalysts was:AHM>TDM-D>MoNaph>thermal>MoS₂ powder>TDM-W.Also,the effect of reaction temperature on the HDO conversion was explained in terms of equilibrium of reversible reaction kinetics.The main products of the HDO for phenolic compounds were identified by gas chromatography/mass spectrometry(GC/MS).The results showed that the product distribution and the HDO selectivity were correlated with the reaction temperature.Two parallel reaction routes,direct hydrogenolysis and combined hydrogenation-hydrogenolysis,were confirmed by the analysis of the product distribution.High temperature favored hydrogenolysis over hydrogenation for HDO of phenol and 4-methoxyphenol,whereas for 4-methylphenol the reverse was true.

A series of the Pt-Sn/SBA-15 catalysts were prepared and their properties characterized by using X-ray powder diffraction(XRD),N₂ adsorption-desorption,high resolution transmission electron microscope,X-ray photoelectron spectroscopy(XPS)and H₂-temperature programmed reduction.Their performances in long chain alkane dehydrogenation were evaluated in a fixed-bed microreactor with dodecane as a model alkane.The results indicated that SBA-15 maintained the well-order mesoporous structure during the reaction.The performance of the catalyst was found not dominated by its textural properties,but by the molar ratio of Sn to Pt which governed the degree of Sn reduction.Owing to the highest degree of Sn reduction,1%(by mass)Pt-1.8%(by mass)Sn/SBA-15 showed the best catalytic activity.At 0.1 MPa and 470℃,the molar ratio of hydrogen to alkane at 4,and liquid hourly space velocity(LHSV)20 h^-1,the dodecane conversion is 10%,and the dodecene selectivity is about 70%.

To overcome the problem that soft sensor models cannot be updated with the process changes,a soft sensor modeling algorithm based on hybrid fuzzy c-means(FCM)algorithm and incremental support vector machines(ISVM)is proposed.This hybrid algorithm FCMISVM includes three parts:samples clustering based on FCM algorithm,learning algorithm based on ISVM,and heuristic sample displacement method.In the training process,the training samples are first clustered by the FCM algorithm,and then by training each clustering with the SVM algorithm,a sub-model is built to each clustering.In the predicting process,when an incremental sample that represents new operation information is introduced in the model,the fuzzy membership function of the sample to each clustering is first computed by the FCM algorithm.Then,a corresponding SVM sub-model of the clustering with the largest fuzzy membership function is used to predict and perform incremental learning so the model can be updated on-line.An old sample chosen by heuristic sample displacement method is then discarded from the sub-model to control the size of the working set.The proposed method is applied to predict the p-xylene(PX)purity in the adsorption separation process.Simulation results indicate that the proposed method actually increases the model's adaptive abilities to various operation conditions and improves its generalization capability.

A control method of direct adaptive control based on gradient estimation is proposed in this article.The dynamic system is embedded in a linear model set.Based on the embedding property of the dynamic system,an adaptive optimal control algorithm is proposed.The robust convergence of the proposed control algorithm has been proved and the static control error with the proposed method is also analyzed.The application results of the proposed method to the industrial polypropylene process have verified its feasibility and effectiveness.

The solubility of carbon monoxide in phenol+ethanol mixed solvents at elevated pressures is reported in this article.The experimental results revealed the influence of pressure on the solubility of CO in phenol+ethanol mixtures.These mixtures are a poorer solvent for carbon monoxide.The solubility of CO is a linear function of pressure,and the extended Henry's constants were presented at different concentrations of phenol.The cubic Soave-Redlich-Kwong equation of state was used to correlate the experimental gas liquid equilibrium data and to predict the solubility of CO.At the same time,the binary interaction parameters,k_ij,for CO-phenol,CO-ethanol and phenol-ethanol systems were estimated by fitting experimental GLE data at 303.15 K and at 2.0-9.0 MPa.Hence,a model was suggested for the solubility of CO in phenol+ethanol mixed solvents.The agreement between experimental and calculated solubilities with the proposed model was rather satisfactory.

Alpha functions of Soave-Redlich-Kwong(SRK)equation of state proposed by Soave,Twu,and Luo were different in mathematic tendency.They were compared in modeling methane-alkanes equilibria with van der Waals mixing rule and Modified Huron-Vidal(MHV1)mixing rule,respectively.Results showed that Luo's alpha function was a little more accurate than Soave's,and Twu's alpha function lacked accuracy in modeling methane-alkanes equilibrium.SRK equation of state was expanded as virial form,and then the equivalent terms were contrasted with terms of virial equation of state.Results showed that Soave's and Luo's alpha functions matched the tendency of virial coefficient better than Twu's,and Luo's alpha function matched better than Soave's in wide temperature range,which sustained the conclusions of phase equilibria calculation.Luo's alpha function keeps decreasing when T_r>1 and becomes negative at sufficient high temperature,thus the conventional cubic equation of state expressed pressure as the sum of repulsion pressure p_R(>0),and attraction pressure p_A(<0)could be improved to be the sum of hard-sphere repulsion pressure p_H(>0)and intermolecular force pressure pI(pI<0 at low temperature and p_I>0 at sufficient high temperature).

An upflow mode membrane-less microbial fuel cell(ML-MFC)was designed for wastewater treatment. Granular graphite electrodes,which are flexible in size,were adopted in the ML-MFC.Microbes present in anaerobic activated sludge were used as the biocatalyst and artificial wastewater was tested as substrate.During the electrochemically active microbe enrichment stage,a stable power output of 536 mW·m^-3 with reference to the anode volume was generated by the ML-MFC running in batch mode.The voltage output decreased from 203 mV to about 190 mV after the ML-MFC was changed from batch mode to normally continuous mode,indicating that planktonic electrochemically active bacterial strains in the ML-MFC may be carried away along with the effluent.Cyclic voltammograms showed that the attached microbes possessed higher bioelectrochemical activity than the planktonic microbes.Forced aeration to the cathode benefited the electricity generation obviously.Higher feeding rate and longer electrode distance both increased the electricity generation.The coulombic yield was not more than 20% throughout the study,which is lower than that of MFCs with membrane.It is proposed that dissolved oxygen diffused from the cathode to the anode may consume part of the substrate.

Sequence hybrid biological reactor(SHBR)was proposed,and some key control parameters were investigated for nitrogen removal from wastewater by simultaneous nitrification and denitrification(SND)via nitrite. SND via nitrite was achieved in SHBR by controlling demand oxygen(DO)concentration.There was a programmed decrease of the DO from 2.50 mg·L^-1 to 0.30 mg·L^-1, and the average nitrite accumulation rate(NAR) was increased from 16.5% to 95.5% in 3 weeks.Subsequently,further increase in DO concentration to 1.50 mg·L^-1 did not destroy the partial nitrification to nitrite.The results showed that limited air flow rate to cause oxygen deficiency in the reactor would eventually induce only nitrification to nitrite and not further to nitrate.Nitrogen removal efficiency was increased with the increase in NAR,that is,NAR was increased from 60% to 90%,and total nitrogen removal efficiency was increased from 68%to 85%.The SHBR could tolerate high organic loading rate(OLR), COD and ammonia-nitrogen removal efficiency were greater than 92% and 93.5%,respectively,and it even operated under low DO concentration(0.5 mg·L^-1 )and maintained high OLR(4.0 kg COD·m^-3·d^-1).The presence of biofilm positively affected the activated sludge settling capability,and sludge volume index(SVI)of activated sludge in SHBR never hit more than 90 ml·g^-1 throughout the experiments.

A mathematical model for enargite bioleaching at 70℃ by Sulfolobus BC in shake-flasks has been constructed.The model included(1)the indirect leaching by Fe³⁺ and Fe³⁺ regeneration by suspended Sulfolobus,and (2)the direct leaching by the attached Sulfolobus.The model parameters were optimized using genetic algorithm (GA).Simulations of the ferric leaching and bioleaching processes were done using this model.The dynamic changes of the concentrations of CuFe²⁺,AsFe³⁺,AsFe⁵⁺,FeFe³⁺ and/or FeFe²⁺,as well as ferric-arsenate precipitation were accurately predicted.

The preparation of ultra-fine particles of salbutamol sulphate(SS)was accomplished with a reactive precipitation pathway,in which salbutamol and sulphuric acid were used as reactants with the solvents of ethanol. The effects of sulphuric acid concentration,reaction temperature,stirring rate,and reaction time on the size of the particle were investigated.A binary mixture composed of lactose and SS was prepared to evaluate SS.The results showed that ultra-fine SS particles with controlled diameters ranging between 3μm and 0.8μm and with a narrow distribution could be achieved.The morphology consisting of clubbed particles was successfully obtained.The purity of the particles reached above 98% with UV detection.The dose of dry powder inhalation was obtained by blending the particles with recrystallized lactose,which acted as a carrier.The deposition quantity of the drug in breathing tract was estimated using a twin impinger apparatus.Compared with the Shapuer powder(purchased in the market),the results showed that SS particles had more quantities subsided in simulative lung.

The biodegradations of phenol and 4-chlorophenol(4-cp)were studied using the mutant strain CTM 2 obtained by the He-Ne laser irradiation on wild-type Candidatropicalis.The results showed that the capacity of the CTM 2 to biodegrade 4-cp was increased up to 400 mg·L^-1 within 59.5 h.In the dual-substrate biodegradation,both velocity and capacity of the CTM 2 to degrade 4-cp increased with low-concentration phenol.A total of 400 mg·L^-1 4-cp was completely degraded within 50.5 h in the presence of 300 mg·L^-1 phenol.The maximum 4-cp biodegradation could reach 440 mg·L^-1 with 120 mg·L^-1 phenol.Low-concentration 4-cp caused great inhibition on the CTM 2 to degrade phenol.In addition,the kinetic behaviors were described using the kinetic model proposed in this lab.

Polyvinylidenefluoride(PVDF)hollow fiber ultrafiltration membrane is frequently employed in water treatment.However,the fouling of ultrafiltration membranes affects the economic effectiveness of such process significantly.The ultrasound generated by flat plate transducer(UFPT)was used to clean the polluted PVDF ultrafiltration membrane with 2 g·L^-1 of citric acid aqueous solution in our study.The effects of UFPT intensity on the membrane surface were studied.The new membrane was easy to be polluted by the saturated CaCl₂ solution.A synergistic effect of UFPT and 2 g·L^-1 citric acid aqueous solution could remove the foul of the membrane,and its flux could be recovered about 81%.The flux recovery of old membrane polluted was increased to 73.2% after 7 h soaking in citric acid aqueous solution,but its flux recovery without soaking was only increased to 56.2%.

A new nanometer material,nanometer AlO(OH)loaded on the fiberglass with activated carbon fibers felt(ACF)as the carrier,was prepared by hydrolytic reaction for the removal of Cd(II)from aqueous solution using column adsorption experiment.As was confirmed by XRD determination,the hydrolysis production loaded on fiberglass was similar to the orthorhombic phase AlO(OH).SEM images showed that AlO(OH)particles were in the form of small aggregated clusters.The Thomas model was applied for estimating the kinetic parameters and the saturated adsorption ability of Cd(II)adsorption on the new adsorbent.The results showed that the maximum adsorption capacity of Cd(Ⅱ)was 128.50 mg·g^-1 and 117.86 mg·g^-1 for the adsorbent mass of 0.3289 g and the adsorbent mass of 0.2867 g,respectively.The elution experiment result indicated that the adsorbed Cd ions was easily desorbed from the material with 0.1 mol·L^-1 HCl solution.Adsorption-desorption cycles showed the feasibility of repeated uses of the composited material.The adsorption capacities were influenced by pH and the initial Cd(Ⅱ) concentration.The amount adsorbed was greatest at pH 6.5 and the initial Cd(Ⅱ)concentration of 0.07 mg·L^-1,respectively.Nanometer AlO(OH) played a major role in the adsorption process,whereas the fiberglass and ACF were assistants in the process of removing Cd(Ⅱ).In addition,the adsorption capacities for Cd(II)were obviously reduced from 128.50 mg·g^-1 to 64.28 mg·g^-1 when Pb ions were present because Pb ions took up more adsorption sites.

This article presents an acetylene production process by partial oxidation/combustion of natural gas. The thermodynamic performance and exergy analysis in the process are investigated using the flow-sheeting program Aspen Plus.The results indicate that the most important destruction of exergy is found to occur in the reactor and water quenching scrubber,amounting to 8.23% and 10.39%,respectively,of the entire system.Based on the results of thermodynamic and exergy analysis,the acetylene reactor has been retrofitted.The improvement ratios of molar O₂ to CH₄ and molar CO to CH₄ are 0.65 and 0.20,respectively.An improvement of the acetylene production system is proposed.Adopting the improvement operation conditions and using oil to realize the reaction heat recovery,the feedstock of natural gas is reduced by 9.88%and the exergy loss in the retrofitting process is decreased by 19.71%compared to the original process.

Ferrocenium monocations as photoinitiators for cationic photopolymerization suffer from a limitation of low absorption and low reactivity under high-pressure Hg lamp.Here,a ferrocenium dication salt,biphenyl bis [(π-cyclopentadienyl)iron]hexafluorophosphate([bis(Cp-Fe)-biphenyl](PF₆)₂ was synthesized by the ligand exchange reaction between ferrocene and biphenyl.The chemical structure was characterized with FTIR and ¹HNMR. The separation of ferrocenium monocation cyclopentadien-iron-biphenyl hexafluorophosphate([Cp-Fe-biphenyl] PF₆)and dication[bis(Cp-Fe)-biphenyl](PF₆)₂ was carried out by column chromatography.The photoactivity of initiating photopolymerization of epoxide ERl4221 was studied as a cationic photoinitiator.[Bis(Cp-Fe)-biphenyl](PF₆)₂ can efficiently absorb radiation above 300nm and its photoactivity is higher than that of its monocation.