Adsorption equilibria of CH_4 and N_2 on activated carbon andsilica gel were measured for a wide temperature range covering thecritical point: 158-298 K for CH_4, and 103-298 K for N_2. Thedetermination of the compres...Adsorption equilibria of CH_4 and N_2 on activated carbon andsilica gel were measured for a wide temperature range covering thecritical point: 158-298 K for CH_4, and 103-298 K for N_2. Thedetermination of the compressibility factor is shown to haveconsiderable effect on isotherm behavior at conditions after theisotherm maximum. A change in adsorption mechanisms on crossing thecritical temperature was observed in all cases. The kind ofadsorbents and how far the equilibrium temperature to the criticalone are major factors affecting the Transition of isotherms from sub-to supercritical.展开更多
Production of 6-aminopenicillanic acid (6-APA) by hydrolysis using penicillin acylase (PA) was studied as a model of an enzymatic emulsion liquid membrane (ELM) process. The loss of PA activity was examined for variou...Production of 6-aminopenicillanic acid (6-APA) by hydrolysis using penicillin acylase (PA) was studied as a model of an enzymatic emulsion liquid membrane (ELM) process. The loss of PA activity was examined for various membrane compositions (organic solvent, surfactant, carrier). The effects of some experimental variables on the stability of emulsion were investigated. It was found that the choice of organic solvent greatly affected the stability of the emulsion. Increasing the concentration of the carrier in the membrane phase increases the transfer rate of substrate and products but also has a destabilizing effect on the emulsion. The recovery of 6-APA obtained by a di-carrier system (N263-N1923) was much higher than those when either of the di-carriers was used separately. The whole process was controlled both by the enzymatic reaction rate and by the transfer rate of the substrate and the products, however, the ratio of them could be changed by varying the composition of the system. For an optimum condition, it was obtained that the recovery ratio of 6-APA was over 80% and the conversion of benzyl penicillin (PG) was up to 90% in the external phase after 30 minutes. Meanwhile, the breakage percentage of the emulsion was less than 2%.展开更多
A model is presented for predicting the fluid velocity distribution around a rising bubble which startsfrom rest on a distillation column tray by considering the unsteady fluid flow based on the method of streamfuncti...A model is presented for predicting the fluid velocity distribution around a rising bubble which startsfrom rest on a distillation column tray by considering the unsteady fluid flow based on the method of streamfunction. Experimental measurement of the velocity distribution by using whole field digitized PIV (particle imagevelocimetry) method is briefly described. The velocity distribution predicted by the present model is in betteragreement with the measurements than the others models published in literature.展开更多
In this paper the modern electron optical equipment is used to translate the clear image of speed moving bubbles in bubbling liquid on a sieve tray into the digital information stored in computer, and the computer aid...In this paper the modern electron optical equipment is used to translate the clear image of speed moving bubbles in bubbling liquid on a sieve tray into the digital information stored in computer, and the computer aided image processing technique is utilized to measure the bubble size distributions and interfacial areas under various operating conditions. And the dynamic behavior of bubbles in turbulent liquid is analyzed theoretically; the mechanism of bubble deformation and breakage is explored on the basis of Kolmogoroff′s isotropic turbulence hypothesis; the mathematical model for predicting the gas liquid interfacial area is proposed. The comparison between the simulated results and the experimental data shows that the model is higher in accuracy, simple in form and convenient in use.展开更多
The radial distribution of the axial component of time-average liquid velocity and turbulent intensity in a gas-liquid bubble column was investigated experimentally using Laser Doppler Anemometer (LDA). The effects of...The radial distribution of the axial component of time-average liquid velocity and turbulent intensity in a gas-liquid bubble column was investigated experimentally using Laser Doppler Anemometer (LDA). The effects of operating parameters on liquid turbulent intensity are studied and an empirical relationship between turbulent intensity and viscosity was established. Such a relationship can be used conveniently in the calculation of liquid velocity profiles in bubble columns.展开更多
It is proposed that double level programming technique may be adopted in synthesis strategy. Optimization of heat exchanger network structural configuration (the master problem) may be solved at the upper level, leavi...It is proposed that double level programming technique may be adopted in synthesis strategy. Optimization of heat exchanger network structural configuration (the master problem) may be solved at the upper level, leaving the rest operating conditions( the slave problem) being optimized at the lower level. With the uniqueness in mind, an HEN synthesis expert system may be employed to address both the logical constraints and the global operation parameters′ optimization using enhanced sequential number optimization theory.Case studies demonstrate that the synthesis strategy proposed can effectively simplify both the problem solving and the synthesis process. The validity of the strategy recommended is evidenced by case studies′ results compared.展开更多
The metabolism, population dynamics and spa-tial distribution of nitrifying bacteria and heterotrophs in biofilms under the action of direct electric current were in-vestigated by using the micro-slicing technique. Th...The metabolism, population dynamics and spa-tial distribution of nitrifying bacteria and heterotrophs in biofilms under the action of direct electric current were in-vestigated by using the micro-slicing technique. The nitrifi-cation rate of nitrifying bacteria was severely inhibited by a current over 10 Am-2 at lower C/N ratios. Compared to het-erotrophs, the nitrifying bacteria in the surface biofilms were severely inhibited, resulting in a significant decrease in bac-terial density. An increase in current density narrowed the less current-sensitive inner biofilm region, and in addition the density of NO2-oxidizers decreased more significantly than that of NH4-oxidizers in the surface biofilms probably due to electrochemical reactions at the anode. However, the effect of current on both the population dynamics and the spatial distribution of the microbial species was less signifi-cant at larger C/N ratios.展开更多
基金Supported by the Special Funds of Major State Basic Research Projects (G2000026404) and the National Natural Science Foundation of China (No. 29936100).
文摘Adsorption equilibria of CH_4 and N_2 on activated carbon andsilica gel were measured for a wide temperature range covering thecritical point: 158-298 K for CH_4, and 103-298 K for N_2. Thedetermination of the compressibility factor is shown to haveconsiderable effect on isotherm behavior at conditions after theisotherm maximum. A change in adsorption mechanisms on crossing thecritical temperature was observed in all cases. The kind ofadsorbents and how far the equilibrium temperature to the criticalone are major factors affecting the Transition of isotherms from sub-to supercritical.
基金the National Natural Science Foundation of China (No. 29136130).
文摘Production of 6-aminopenicillanic acid (6-APA) by hydrolysis using penicillin acylase (PA) was studied as a model of an enzymatic emulsion liquid membrane (ELM) process. The loss of PA activity was examined for various membrane compositions (organic solvent, surfactant, carrier). The effects of some experimental variables on the stability of emulsion were investigated. It was found that the choice of organic solvent greatly affected the stability of the emulsion. Increasing the concentration of the carrier in the membrane phase increases the transfer rate of substrate and products but also has a destabilizing effect on the emulsion. The recovery of 6-APA obtained by a di-carrier system (N263-N1923) was much higher than those when either of the di-carriers was used separately. The whole process was controlled both by the enzymatic reaction rate and by the transfer rate of the substrate and the products, however, the ratio of them could be changed by varying the composition of the system. For an optimum condition, it was obtained that the recovery ratio of 6-APA was over 80% and the conversion of benzyl penicillin (PG) was up to 90% in the external phase after 30 minutes. Meanwhile, the breakage percentage of the emulsion was less than 2%.
文摘A model is presented for predicting the fluid velocity distribution around a rising bubble which startsfrom rest on a distillation column tray by considering the unsteady fluid flow based on the method of streamfunction. Experimental measurement of the velocity distribution by using whole field digitized PIV (particle imagevelocimetry) method is briefly described. The velocity distribution predicted by the present model is in betteragreement with the measurements than the others models published in literature.
文摘In this paper the modern electron optical equipment is used to translate the clear image of speed moving bubbles in bubbling liquid on a sieve tray into the digital information stored in computer, and the computer aided image processing technique is utilized to measure the bubble size distributions and interfacial areas under various operating conditions. And the dynamic behavior of bubbles in turbulent liquid is analyzed theoretically; the mechanism of bubble deformation and breakage is explored on the basis of Kolmogoroff′s isotropic turbulence hypothesis; the mathematical model for predicting the gas liquid interfacial area is proposed. The comparison between the simulated results and the experimental data shows that the model is higher in accuracy, simple in form and convenient in use.
基金Supported by the National Natural Science Foundation of China(No.29376253)and the Research Grant by the Distillation Laboratory of State Key Laboratories of Chemical Engineering.
文摘The radial distribution of the axial component of time-average liquid velocity and turbulent intensity in a gas-liquid bubble column was investigated experimentally using Laser Doppler Anemometer (LDA). The effects of operating parameters on liquid turbulent intensity are studied and an empirical relationship between turbulent intensity and viscosity was established. Such a relationship can be used conveniently in the calculation of liquid velocity profiles in bubble columns.
文摘It is proposed that double level programming technique may be adopted in synthesis strategy. Optimization of heat exchanger network structural configuration (the master problem) may be solved at the upper level, leaving the rest operating conditions( the slave problem) being optimized at the lower level. With the uniqueness in mind, an HEN synthesis expert system may be employed to address both the logical constraints and the global operation parameters′ optimization using enhanced sequential number optimization theory.Case studies demonstrate that the synthesis strategy proposed can effectively simplify both the problem solving and the synthesis process. The validity of the strategy recommended is evidenced by case studies′ results compared.
基金supported by the National Natural Science Foundation of China(Grant No.29976030)the Foundation for University Key Teacher of the Ministry of Education of China
文摘The metabolism, population dynamics and spa-tial distribution of nitrifying bacteria and heterotrophs in biofilms under the action of direct electric current were in-vestigated by using the micro-slicing technique. The nitrifi-cation rate of nitrifying bacteria was severely inhibited by a current over 10 Am-2 at lower C/N ratios. Compared to het-erotrophs, the nitrifying bacteria in the surface biofilms were severely inhibited, resulting in a significant decrease in bac-terial density. An increase in current density narrowed the less current-sensitive inner biofilm region, and in addition the density of NO2-oxidizers decreased more significantly than that of NH4-oxidizers in the surface biofilms probably due to electrochemical reactions at the anode. However, the effect of current on both the population dynamics and the spatial distribution of the microbial species was less signifi-cant at larger C/N ratios.
