Mixing, achieved mostly by mechanically stirring, is one of the most important unit operation processes in chemical and related industries. The problem of design and scale-up of stirred tanks has been tackled mainly b...Mixing, achieved mostly by mechanically stirring, is one of the most important unit operation processes in chemical and related industries. The problem of design and scale-up of stirred tanks has been tackled mainly by means of semi-empirical methods.Measurement and numerical simulation of viscous fluid in a stirred tank is still unsufficient and further development is needed.In this paper, computational fluid dynamics (CFD) simulation and digital particle image velocimetry (DPIV) measurement have been carried out to study the flow field of viscous fluid in a stirred tank agitated by a four-blade Ruston turbine.The working medium is a mixture of water and glycerine with various concentrations.The results show the mean velocity, turbulent energy, vorticity and circle flux of the fluids as well as the change of flow patterns with the fluid viscosity.CFD code of CFX with sliding grids was used to simulate the flow field.The k-ε model and laminar model was selected as the models of simulation.The CFD simulations were compared with the experimental DPIV data.The result shows that the CFD simulations can reflect the flow of the viscous fluid in a stirred tank.展开更多
The separation of aromatic hydrocarbons or olefins from paraffins is very important in chemical industry.The volatile organic solvents used are usually harmful to environment and human health.As green solvents,room te...The separation of aromatic hydrocarbons or olefins from paraffins is very important in chemical industry.The volatile organic solvents used are usually harmful to environment and human health.As green solvents,room temperature ionic liquids are potential substitutes for the separation of hydrocarbon products.Activity coefficients at infinite dilution of hydrocarbon solutes,such as alkanes,hexenes,alkylbenzenes and styrene,in 1-butyl-3-methyl imidazolium hexafluorophosphate ([BMIM][PF 6]),1-allyl-3-methylimidazolium tetrafluoroborate ( [AMIM][BF 4]),1-isobutenyl-3-methylimidazolium tetrafluoroborate ([MPMIM][BF 4]) and [MPMIM][BF 4]+AgBF 4 were determined by gas-liquid chromatography.The measurements were carried out at different temperatures between 298.15 K and 318.15 K.The separation effects of these ionic liquids for olefin/paraffin, alkanes/benzene and hexene isomers were discussed.展开更多
Cloud point extraction(CPE) utilizing non-ionic surfactant TX114 was carried out to separate and concentrate di(2-ethyl hexyl) phosphoric acid(D2EHPA) in its dilute aqueous solution.The CPE process was facilitated at...Cloud point extraction(CPE) utilizing non-ionic surfactant TX114 was carried out to separate and concentrate di(2-ethyl hexyl) phosphoric acid(D2EHPA) in its dilute aqueous solution.The CPE process was facilitated at 45℃.The influence of TX114 concentration,D2EHPA concentration and solution acidity on the extraction efficiency was studied.The results showed that extraction efficiency increased with decreasing TX114 concentration and increasing D2EHPA concentration.Such unusual extraction behavior might be the result of the reverse-micelle coacervate phase,solublizing D2EHPA on the surface of micelle,and the influence of D2EHPA on the cloud point of TX114.展开更多
Cloud point extraction (CPE) utilizing polyoxyethylene 10 lauryl ether (C12E10) as the surfactant was carried out to separate and concentrate di(2-ethyl hexyl) phosphoric acid (D2EHPA) in its dilute aqueous solution.T...Cloud point extraction (CPE) utilizing polyoxyethylene 10 lauryl ether (C12E10) as the surfactant was carried out to separate and concentrate di(2-ethyl hexyl) phosphoric acid (D2EHPA) in its dilute aqueous solution.The CPE process was facilitated by decreasing the cloud point (CP) temperature of the solution with sodium sulfate.The influence of C12E10 concentration, settling temperature, pH value, and Ni2+ in the solution on the extraction efficiency (E) was studied.The results showed that extraction efficiency increased with the concentration of C12E10, temperature and pH value of the system.Trace Ni2+ in the solution has no obvious influence on extraction efficiency of D2EHPA when pH=7.00.Single-stage extraction efficiency larger than 85% has been obtained.展开更多
Ultrafine particles of CaCO3 were synthesized with micropore dispersion in gas-liquid （slurry） systems.Experiments was conducted on carbonation of Ca（OH）2/H2O system.Micropore plate was used for the dispersion of ...Ultrafine particles of CaCO3 were synthesized with micropore dispersion in gas-liquid （slurry） systems.Experiments was conducted on carbonation of Ca（OH）2/H2O system.Micropore plate was used for the dispersion of mixed gas containing CO2.Therefore,the processes of momentum transfer, mass transfer and reaction were enhanced.The results showed that ultrafine particles with diameter about 40nm and specific surface area more than 30 m2·g -1 were prepared successfully.The crystal structure of particles was characterized with BET, FTIR and TEM.展开更多
Preparation of a novel coating is one of the keys to solid phase microextraction.A new method was proposed to prepare a chitosan microprobe with a film thickness of several dozen micrometers with the phase inverse tec...Preparation of a novel coating is one of the keys to solid phase microextraction.A new method was proposed to prepare a chitosan microprobe with a film thickness of several dozen micrometers with the phase inverse technique by using a microporous polyacrylonitrile (PAN) hollow fiber with a diameter of 1.5 mm as template.The dilute acetic acid solution of chitosan and glutaraldehyde was added into the hollow fiber, a quartz fiber was inserted into the hollow fiber as supporter and then the hollow fiber was placed in the NaOH solution, because of the porosity of hollow fiber, NaOH diffused and contacted with acetic acid, then the chitosan thin film was formed.For intensifying the adsorption of acidic compounds, the probe was then modified with polyethyleneiminate (PEI).The SEM photos showed that the probe obtained with this process was 17 μm thick.The PEI-modified chitosan probes showed stronger adsorption of furomeside.Using NaOH as desorber, a concentration factor over 10 was observed and the solute concentration in the desorber was linear with that in the original samples.The operation is convenient and easy to realize automation.展开更多
基金国家自然科学基金项目 (No 2 983 613 0 )清华大学基础研究基金项目 (No JZ2 0 0 0 0 0 8)~~
文摘Mixing, achieved mostly by mechanically stirring, is one of the most important unit operation processes in chemical and related industries. The problem of design and scale-up of stirred tanks has been tackled mainly by means of semi-empirical methods.Measurement and numerical simulation of viscous fluid in a stirred tank is still unsufficient and further development is needed.In this paper, computational fluid dynamics (CFD) simulation and digital particle image velocimetry (DPIV) measurement have been carried out to study the flow field of viscous fluid in a stirred tank agitated by a four-blade Ruston turbine.The working medium is a mixture of water and glycerine with various concentrations.The results show the mean velocity, turbulent energy, vorticity and circle flux of the fluids as well as the change of flow patterns with the fluid viscosity.CFD code of CFX with sliding grids was used to simulate the flow field.The k-ε model and laminar model was selected as the models of simulation.The CFD simulations were compared with the experimental DPIV data.The result shows that the CFD simulations can reflect the flow of the viscous fluid in a stirred tank.
文摘The separation of aromatic hydrocarbons or olefins from paraffins is very important in chemical industry.The volatile organic solvents used are usually harmful to environment and human health.As green solvents,room temperature ionic liquids are potential substitutes for the separation of hydrocarbon products.Activity coefficients at infinite dilution of hydrocarbon solutes,such as alkanes,hexenes,alkylbenzenes and styrene,in 1-butyl-3-methyl imidazolium hexafluorophosphate ([BMIM][PF 6]),1-allyl-3-methylimidazolium tetrafluoroborate ( [AMIM][BF 4]),1-isobutenyl-3-methylimidazolium tetrafluoroborate ([MPMIM][BF 4]) and [MPMIM][BF 4]+AgBF 4 were determined by gas-liquid chromatography.The measurements were carried out at different temperatures between 298.15 K and 318.15 K.The separation effects of these ionic liquids for olefin/paraffin, alkanes/benzene and hexene isomers were discussed.
文摘Cloud point extraction(CPE) utilizing non-ionic surfactant TX114 was carried out to separate and concentrate di(2-ethyl hexyl) phosphoric acid(D2EHPA) in its dilute aqueous solution.The CPE process was facilitated at 45℃.The influence of TX114 concentration,D2EHPA concentration and solution acidity on the extraction efficiency was studied.The results showed that extraction efficiency increased with decreasing TX114 concentration and increasing D2EHPA concentration.Such unusual extraction behavior might be the result of the reverse-micelle coacervate phase,solublizing D2EHPA on the surface of micelle,and the influence of D2EHPA on the cloud point of TX114.
文摘Cloud point extraction (CPE) utilizing polyoxyethylene 10 lauryl ether (C12E10) as the surfactant was carried out to separate and concentrate di(2-ethyl hexyl) phosphoric acid (D2EHPA) in its dilute aqueous solution.The CPE process was facilitated by decreasing the cloud point (CP) temperature of the solution with sodium sulfate.The influence of C12E10 concentration, settling temperature, pH value, and Ni2+ in the solution on the extraction efficiency (E) was studied.The results showed that extraction efficiency increased with the concentration of C12E10, temperature and pH value of the system.Trace Ni2+ in the solution has no obvious influence on extraction efficiency of D2EHPA when pH=7.00.Single-stage extraction efficiency larger than 85% has been obtained.
文摘Ultrafine particles of CaCO3 were synthesized with micropore dispersion in gas-liquid （slurry） systems.Experiments was conducted on carbonation of Ca（OH）2/H2O system.Micropore plate was used for the dispersion of mixed gas containing CO2.Therefore,the processes of momentum transfer, mass transfer and reaction were enhanced.The results showed that ultrafine particles with diameter about 40nm and specific surface area more than 30 m2·g -1 were prepared successfully.The crystal structure of particles was characterized with BET, FTIR and TEM.
文摘Preparation of a novel coating is one of the keys to solid phase microextraction.A new method was proposed to prepare a chitosan microprobe with a film thickness of several dozen micrometers with the phase inverse technique by using a microporous polyacrylonitrile (PAN) hollow fiber with a diameter of 1.5 mm as template.The dilute acetic acid solution of chitosan and glutaraldehyde was added into the hollow fiber, a quartz fiber was inserted into the hollow fiber as supporter and then the hollow fiber was placed in the NaOH solution, because of the porosity of hollow fiber, NaOH diffused and contacted with acetic acid, then the chitosan thin film was formed.For intensifying the adsorption of acidic compounds, the probe was then modified with polyethyleneiminate (PEI).The SEM photos showed that the probe obtained with this process was 17 μm thick.The PEI-modified chitosan probes showed stronger adsorption of furomeside.Using NaOH as desorber, a concentration factor over 10 was observed and the solute concentration in the desorber was linear with that in the original samples.The operation is convenient and easy to realize automation.
