Simulations and experiments on the flow field were used to study the internal flow and turbulence in a vane-guided hydrocyclone.The main factors resulting in droplet coalescence and breakup are viscous shear force related to the velocity gradient and the high shear stress and turbulent kinetic energy in the turbulence.Moreover, the positions in the hydrocyclone where droplets inclined to coalesce and break were investigated.In order to understand the relative importance of droplet coalescence and breakup in the vane-guided hydrocyclone, the separation performance as its characteristic was verified.The experiments on the separation performance also show that the structural parameters, such as the number and outlet angle of guided vanes, and operating parameters, such as the inlet velocity, split ratio, inlet concentration and operating temperature, affect the droplet coalescence and breakup in the vane-guided hydrocyclone.

Salt influence the quality of crude oil and equipment.Branch-composite polyether derivative is studied which forms reverse micelles in non-polar continuous phase.With the advantage that the pool in reverse micelles can dissolve polar materials, water-soluble impurities and salt can be separated from crude oil.The branch-composite polyether derivative can reduce the surface tension of high-salinity water and its salt-resistance is up to 200000 mg·L^-1.Thus it can be used in salinity water washing. Moreover,the branch-composite polyether derivative can inhibit the corrosion of metal in salt water effectively.

Some experiments were conducted to investigate the effect of addition of adipic acid on absorption and desorption processes of CO₂ in MEA solutions.For the desorption of CO₂ in MEA with concentration of 0.4 mol·L^-1, the energy consumption was decreased by addition of adipic acid, and the desorption rate was improved.The absorption capacity of lean solvents was decreased in the second absorption processes, but only a small difference (<7%）was observed between the amounts of CO₂ absorbed in lean solvents with/without addition of adipic acid.When the same amount of adipic acid was added directly into the MEA solvent at the beginning of absorption process, the absorption capacity for CO₂decreased.For the MEA solutions with higher concentrations (7 mol·L^-1 and 12 mol·L^-1), and the decreases in the absorption capacity resulted from the addition of adipic acid was less as the concentration increased, the energy consumption for desorption decreased considerably, and the desorption rate increased.By comparison of the effect on absorption and desorption of CO₂, it is concluded that addition of adipic acid is effective to reduce the energy requirement in solvent absorption of CO₂.

The oil-phase concentration distribution in a vane-guided hydrocyclone was numerically simulated with the Reynolds stress model and Euler-Euler method.The effects of operating parameters, physical parameters and air core on the oil-phase concentration field were studied.Predictions are in reasonable agreement with the experimental results.The oil concentration decreased as the radial position increased and as the axial position decreased in the water-oil flow field.The analysis with Stokes law showed that the tendency of oil moving to the axis and overflowing out increased with the increase of inlet velocity, density difference of oil and water, and inlet concentration.Moreover, the air core changed the concentration distribution in the hydrocyclone, so that water, oil and air formed a water-oil-air flow field from wall to axis.

Detective variables of industrial processes show nonlinear and non-Gaussian behavior.This paper proposes the kernel principal component analysis (WKPCA）based on wavelet kernel clustering to handle the nonlinearity of the process, and introduces support vector data description (SVDD）to model the process.The first step is to construct the kernel function by using Morlet wavelet because of its advantages of multi-resolution analysis and good fitness, which could enhance nonlinear mapping and anti-noise capability of the kernel function.Then this method uses cluster analysis in the feature space, and chooses the data which represent the characteristic center in every cluster, which could decrease calculation load of the kernel function.Finally the method uses the monitor statistics offered by SVDD to describe the non-Gaussian information.Application to the Tennessee-Eastman benchmark process showed effectiveness and accuracy of detecting fault and exception generated by the system.

The economic performance of real-time optimization system is influenced by the accuracy of the model.If the process model deviates from the process plant, it would lead to the offset between the true plant optimum and the predicted optimum and decrease the efficiency of real-time optimization.So it is important to use parameter estimation to make sure the least deviation of the optimum from the true plant.The definition of parameter estimability is proposed for parameter estimation problem with finite measurement information based on the definition of system estimability.The necessary conditions for parameter estimability are stated in both linear and nonlinear systems based on matrix analysis.If the parameters of system are inestimable, the parameter estimability can be changed by fixing some of the modelparameters.The relationship between parameter estimability and the number of data sets is discussed.The effectiveness of the proposed analysis can be demonstrated by the results of linear and nonlinear systems.

The adsorption of alkylmorpholine (DMP）on NaCl and KCl crystals was studied with the density functional theory (GGA-PW91）using computer simulation, where NaCl (100）with F color center and KCl (100）with O^-₂ defect.The charges of ions on NaCl(100）are changed to positive by F color center, while the charges of ions on KCl (100）are changed to negative by O^-₂.The adsorption energy of DMP on Na-top is -157.00 kJ·mol^-1 and that on KCl (100）with O^-₂ is -59.14 kJ·mol^-1.Therefore, DMP can be adsorbed on both NaCl and KCl, and the interaction between NaCl and DMP is stronger.The flotation experiments on the overflow potash ore containing alkylmorpholine indicate that the flotation recovery for NaCl is high, while the recovery of KCl is low.This result reflects different adsorption characteristics of DMP on surfaces of NaCl and KCl, which corroborates the result of computer simulation.

The effect of induction temperatures on porcine interferon-α(pIFN-α）production byPichia pastoris was investigated in a 10 L bioreactor with methanol concentration controlled at a specific level. The results indicated that a low temperature was obviously beneficial for pIFN-α expression, and the highest pIFN-α antiviral activity reached a level of 1.5×10⁶ IU·ml^-1 when induction was made at 20℃, that was 150-folds of the maximal value obtained with the traditional induction strategy at 30℃.On-line multi-variable measurement of the fermentative state variables and metabolic analysis showed that cell metabolic activity and specific methanol consumption rate (0.036 h^-1）could be higher with induction at 20

Cellobiase (CB）is an important component in the cellulase system.At present, the cellulase preparation produced by Trichoderma reesei is poor in cellobiase and restricts the conversion of cellobiose to glucose.In this study, the CB gene of 2526bp from Aspergillus niger was cloned by the reverse transcription PCR method, and was inserted between the strong promoter Pcbh1 (including secreting signal peptide sequence）and the terminator Tcbh1 from T.reesei to construct a recombinant plasmid pHB9 including the hygromycin B resistance marker.The plasmid pHB9 was transformed into the conidia of T.reesei by using the PEG-CaCl₂ method to obtain 387 positive transformants.Ten fast growth transformants were isolated by the rescreening culture plates using cellobiose as sole carbon source.It was confirmed that the CB gene from A.niger was integrated into the chromosomal DNA ofT.reesei by the PCR test.Cellulase production by the recombinant transformants was performed in shaking flasks, and five high CB activity transformants were obtained.After 48h fermentation, the CB activity in culture broth could reach 5.3 IU·ml^-1, which was 106 times that of the host strain.It demonstrated that CB gene from A.niger was efficiently expressed and the enzyme was successfully secreted.

In this work, the gas production potential from hydrates at the SH7 drilling site of the Shenhu Area by means of the huff and puff method using a single horizontal well was estimated.3 dimensional numerical model was established based on currently available data from site measurements.The hydrate accumulations in Shenhu Area are similar to Class 3 deposits (involving only a HBL), and the overburden and underburden layers are assumed to be permeable.The simulation results indicate that the hydrate dissociated zone expands around the well, and the hydrate formation occurs during the injection stage of the huff and puff process.Reasonable injection and production rates should be adopted to avoid the over pressurization and depressurization during each huff and puff cycle.Thermal stimulation is shown to have an effect over a limited range around the well. The gas production rate and gas to water production ratio in the Class 3 hydrate deposit at site SH7 in Shenhu Area in this work is not suitable for commercial production.

A low recovery rate was observed in the treatment of finished water from sedimentation tank with a UF membrane system, and recovery of membrane backwash water can improve productivity and reduce the cost of membrane treatment systems.In this study, two bench-scale coagulation microfiltration membrane systems were installed.The raw water of one membrane system was a blend of water from the pre-treated membrane backwash water and Luan River water in a 1∶9 ratio.Another membrane system was used to treat Luan River water.The aim of this study was to investigate effect of various pre-treatments on the finished water quality and membrane fouling rate.The results showed that the produced water quality from the mixed water system was improved with the addition of PAC in the pre-treatment of membrane backwash water, which was compared to the results obtained by coagulation.The removal rates of UV₂₅₄ and COD_Mn were increased by 9% and 6.3%, respectively.There was no difference in turbidity of the produced waters by the various pre-treatments.Moreover, attenuation rate of SF was reduced by 16.6% with adding PAC in the pre-treatment.And the produced water quality from Luan River water system and membrane fouling rate were similar to those in mixed water system when the PAC was added in the pre-treatment.

The recovering system (multi-effect evaporation）of butanone-toluene solvent of dewaxing process is simulated with a process simulator.It is shown that good results can be obtained when the complex oil and/or wax mixtures is replaced with a pseudo-single heavy hydrocarbon component in the simulation.The results obtained in this work are comparable to that obtained by the TBP (true boiling point curve）method.One of the possible reasons might be that there is very large difference between molecule properties of the solvent and original oil and/or wax.Compared to the large difference, the difference of molecule properties becomes less important in the oil and/or wax mixture.Therefore, it is possible in the simulation to use a pseudo-single heavy hydrocarbon component instead of complex oil and/or wax mixtures and satisfactory results can be obtained, which can make simulation calculation simple and is favorable for analysis and study of the solvent recovering system.These simulation results have been successfully used in the retrofit of the solvent recovering units in butanone-toluene dewaxing process at a Chinese company for energy saving.

A strain of Alcaligenes sp., DN25, isolated and preserved in the authors’ lab, shows a high cyanide-degrading activity and thus has a potential of industrial application.The cyanide-degrading routes were determined based on the analysis of degradation products and time curves.The experiments on optimization of culture conditions for the cyanide-degrading enzyme were carried out according to the characteristics of enzyme active site.The results demonstrated that the reaction was through a hydrolytic pathway co-functioned by a cyanide hydratase, an amidase and a cyanide hydrolase, among which cyanide hydrolase played a major role.Four sulfur-containing substances were added to the medium to test the effect on specific activity of culture.DL-cysteine was found to be beneficial for the enzyme production and DL-methionine for both enzyme production and cell yield, resulting in increased specific activity of culture of 1.26 U·ml^-1 and 2.10 U·ml^-1，when 0.8% DL-cysteine and DL-methionine was added into fermentation culture respectively.The experiments on optimization of liquid culture conditions in 1L shake flask gave the optimal conditions as 100ml of liquid loading, pH of 9.0, inoculation size of 8%, and 0.8% DL-methionine added into the medium.Under such conditions, the specific activity of culture could reach 2.18 U·ml^-1, increased by 3.46 fold compared to that before optimization.The cell growth curve had a similar trend to that of enzyme production and the stabilized phase could be reached within 40 h.The current work could lay the basis for further application and purification of the cyanide-degradating enzyme.

Advanced treatment of high-viscosity petrochemical wastewater was studied with the oxidation method by Fenton’s reagent as oxidant and the oxidation mechanism and kinetics were analyzed.According to the results from a series of single-factor experiments, it was observed that the control parameters in the oxidation process had different effects on COD removal rate.Through comparing those experimental results, a desirable COD removal rate of 62.00% was obtained at initial mass ratio R（=H₂O₂/COD）=1.52, molar ratio M（=H₂O_2/Fe²⁺）=10∶1, initial pH 3.0 and temperature of 25℃.A kinetic study was carried out by using a modified pseudo-first-order model with the reaction constant of k computed by multiple regression analysis.The experiments performed at different temperatures allowed the calculation of the Arrhenius equation parameters and the global activation energy E_a (25.5 kJ·mol^-1）for the pseudo-first-order reaction.

Oxy-fuel combustion has an advantage of easy CO₂ recovery due to its high CO₂ concentration in exhausted gas.It is a promising combustion method for coal.In this work, the change of conversion ratio of fuel-N to NO with CO₂ concentration, reduction ratio of recycled NO in the reducing zone of volatile matter combustion, and the influence of recycled NO on conversion ratio of fuel-N to NO were investigated, and corresponding correlations were obtained.With these experimental results and theoretical analysis on the material balance in the system, the conversion ratio of fuel-N to NO in the system was derived.The results revealed that much less NO was released in a dry-recycle system than in a wet-recycle system, due to a higher gas recirculation ratio in the dry-recycle system.With oxy-fuel combustion, NO emission can be reduced to about only 1/7 of conventional air combustion.This effect is mainly attributed to the reduction of recycled NO.NO concentration increases with nitrogen content, but the increase in NO concentration is less than that in nitrogen content.As nitrogen content increases, the conversion ratio of fuel-N to NO of the system decreases.

The feasibility of perfluorobutyric acid (PFBA）degradation by ultrasound irradiation was investigated and the influential factors such as ultrasonic frequency, initial PFBA concentration, sorts of saturated gas and reaction temperature were also evaluated.The experimental results showed that PFBA degradation followed the apparent pseudo-first order kinetic reaction.The sonolysis was completed over a range of frequency from 20 kHz to 1060 kHz at the initial PFBA concentration of 0.47×10^-6  mol·L^-1. However, the PFBA degradation rate constants had an apparent maximum at 610 kHz.Under the 610 kHz ultrasound irradiation, the initial PFBA concentration and the sorts of saturated gas affected greatly the PFBA degradation, and the reaction temperature had a slight effect on the PFBA degradation.In addition, the PFBA degradation in the manufacture wastewater was also evaluated under 610 kHz ultrasound.

Ordered mesoporous carbon material of CMK-3 was prepared with mesoporous silica SBA-15 as template and sucrose as carbon source, then CMK-3 was loaded mono-dispersed Pd by the impregnation-reduction method.The catalyst system nanoparticles Pd/CMK-3 was characterized by X-ray diffraction (XRD), transmission electron microscope (TEM）and N₂ adsorption-desorption, and the results indicated that CMK-3 was ordered mesoporous structure with pore diameter of 5 nm, and Pd/CMK-3 retained the mesoporous structure with Pd particles of different sizes loaded in the channels.Pd/CMK-3 was used in the ligand-free Suzuki-Miyaura C—C coupling reaction as catalyst.The result showed that Pd/CMK-3 had higher stability and activity compared with activated carbon, and addition of water in the solvent was helpful in increasing yield, so when bromobenzene and benzene boric acid reacted at 70℃ for 6 h with potassium carbonate as the base and EtOH / water as the solvent and Pd/CMK-3 as the catalyst, the yield of biphenyl was up to 89.0%.

The melt flow patterns were obtained by using an emulated mold and tracer technique.The effects of water-assisted injection molding conditions on melt flow were investigated based on the patterns.The results showed that the longer the water injection delay time, the nearer the back flow to the water channel, the narrower the melt flow under a strong shear force in the water channel.At a low melt temperature, the melt near the mold wall was hard to flow.A higher melt temperature increased the bubbles in the melt near the water injector, and resulted in a thicker back flow layer.When water pressure was higher, the force that water dragged the melt was stronger, and back flow disappeared in the melt flow field.When water pressure was lower, the melt near the water channel was subjected to a stronger shear force.The high viscous resistance around the water injector was much greater than the resistance resulting from increasing short shot size.

A novel phosphorus-free and nitrogen-free anti-scalant for calcium phosphate and Fe(Ⅲ), maleic anhydride/allyl polyethylene glycol carboxylate (MC_n, n is the degree of polymerization of polyethylene glycol,n=5, 9, 13), was synthesized from allyl polyethylene glycol monoether, chloracetic acid, maleic anhydride, and sodium hydroxide.The product was characterized by FT-IR and 1H-NMR.The performance of calcium phosphate inhibition and dispersancy towards Fe(Ⅲ）was evaluated by the static scale-inhibiting method and light transmittance, respectively.SEM analysis showed a disordered calcium phosphate crystal in the presence of MC_n.The studies indicated that both inhibition and dispersancy increased with increasing degree of polymerization of polyethylene glycol in the structure of MC_n from 5 to  13.MC₁₃ had superior ability to inhibit the precipitation of calcium phosphate, approximately 99% inhibition when the dosage was 6 mg·L^-1, and had excellent dispersancy towards Fe(Ⅲ), about 22% light transmittance when the dosage was 8 mg·L^-1.Inhibition mechanism was proposed that the interactions between all kinds of metallic ions in systems and carboxyl groups on side chains and/or oxygen atoms of ethers were the fundamental impetus to restrain the formation of calcium phosphate scale and disperse Fe(Ⅲ）in cooling water systems.

Waterborne UV curable polyurethane acrylate (PUA)/epoxy acrylate (EA）hybrid emulsion with anomalistic core-shell structure was prepared from waterborne PUA which was used as emulsor and EA resin by the method of phase inversion.FTIR was used to monitor the structure of PUA resin during its synthesis process and the hybrid emulsion before and after UV curing.The test results by transmission electron microscopy (TEM）showed that the particles of emulsion had an anomalous core-shell shape structure, and the particles exhibited different structures with different EA contents.The effects of —COOH content on the system during the process of phase inversion, the emulsification ability of PUA prepolymer, the abilities of the emulsions and its films were investigated.It was shown that the viscosity and electrical conductivity of the system had similar changing trend of change.The biggest value of them both increased and appeared later when —COOH content increased.The emulsification ability of PUA prepolymer also increased with increasing —COOH content.When the content was more than 2.3%, however, the emulsification ability changed little.Furthermore, the higher the —COOH content was, the smaller the particle size of emulsions, the more transparent the appearance, the bigger the viscosity of system, the better the stability of emulsions, and the higher the hardness of UV cured films.The hygroscopic coefficient of UV cured film increased, then decreased and again increased with increasing —COOH

Preparation and application of micron-size poly(methylmethacrylate-co-styrene）/polysiloxane core/shell microspheres

LU Xin, XIN Zhong, LI Chun

2011, 62(2):  539-544. 

Abstract ( 1195 )   PDF (1642KB) ( 496 )  

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Micron-size poly(methyl methacrylate-co-styrene)/polysiloxane core/shell microspheres were synthesized.Firstly, poly(methyl methacrylate-co-styrene）microspheres were prepared by dispersion copolymerization and acted as seed microspheres.Secondly, methyl trimethoxylsilane was hydrolyzed, mixed with the seed microspheres and then condensed to generate polysiloxane shells on the surface of seed microspheres by adding aqueous NH₄OH as catalyst.The morphology, core/shell structure, size and chemical structure of the core/shell microspheres were investigated by SEM, TEM, size analyzer and FTIR, respectively.The refractive indices of the relevant core/shell microspheres decreased with increasing feed amount of methyl methacrylate in the co-monomers in the seeds.The microspheres as light scattering agents were blended with polymethyl methacylate（PMMA）resin to prepare a light scattering material.The results indicated that core/shell microspheres could significantly improve the haze of PMMA sheet (2 mm）and the haze of PMMA sheet was enhanced corresponding to the increase of Δn, the difference of refractive indices between light scattering agents and PMMA.When the concentration of core/shellmicrospheres was between 2% and 3%(mass), the light scattering material with effective light scattering coefficient more than 55% could be obtained.