Experiments have been done on mass transfer to a liquid-liquid interface on which inert gas bubbles are sparged.To simulate the pyrometallurgy system of melten slag-metal(or matte),aqueous solution-mercury(or zinc ama...Experiments have been done on mass transfer to a liquid-liquid interface on which inert gas bubbles are sparged.To simulate the pyrometallurgy system of melten slag-metal(or matte),aqueous solution-mercury(or zinc amalgam) system was used.The mass transfer coefficients of indicator ions as a function of bubble parameters have been determined.The experimental results show satisfactory agreement with the mass transfer model proposed Previously.展开更多
Danckwert’s method was used to determine the specific interfacial area, a, and the individual mass transfer coefficient, kL, during absorption of CO2 in a bubble column with an anionic surfactant in the carbonate-bi...Danckwert’s method was used to determine the specific interfacial area, a, and the individual mass transfer coefficient, kL, during absorption of CO2 in a bubble column with an anionic surfactant in the carbonate-bicarbonate buffer solution and NaAsO2 as catalyst, the presence of which decreases the specific interfacial area and the individual mass transfer coefficient. The specific interfacial area and the individual mass transfer coefficient increase with increasing su- perficial gas velocity. The specific interfacial area decreases whereas the individual mass transfer coefficient increases with increasing temperature. The results of experiments were used to determine the dependence of a, kL, and kLa on the surface tension, the temperature of the absorption phase, and the superficial velocity of the gas. The calculated results from the correlation were found to be within 10% deviation from the actual experimental results.展开更多
The hydrodynamics and mass transfer characteristics of a lab-scale jet bubbling reactor(JBR)including the gas holdup,volumetric mass transfer coefficient and specific interfacial area were assessed experimentally inve...The hydrodynamics and mass transfer characteristics of a lab-scale jet bubbling reactor(JBR)including the gas holdup,volumetric mass transfer coefficient and specific interfacial area were assessed experimentally investigating the influence of temperature,pH and superficial gas velocity.The reactor diameter and height were 11 and 30 cm,respectively.It was equipped with a single sparger,operating at atmospheric pressure,20 and 40℃,and two pH values of 3 and 6.The height of the liquid was 23 cm,while the superficial gas velocity changed within 0.010-0.040 m·s^(-1)range.Experiments were conducted with pure oxygen as the gas phase and saturated lime solution as the liquid phase.The liquid-side volumetric mass transfer coefficient was determined under unsteady-state oxygen absorption in a saturated lime solution.The gas holdup was calculated based on the liquid height change,while the specific interfacial area was obtained by a physical method based on the bubble size distribution(BSD)in different superficial gas velocities.The results indicated that at the same temperature but different pH,the gas holdup variation was negligible,while the liquid-side volumetric mass transfer coefficient at the pH value of 6 was higher than that at the pH=3.At a constant pH but different temperatures,the gas holdup and the liquid-side volumetric mass transfer coefficients at 40℃were higher than that of the same at 20℃.A reasonable and appropriate estimation of the liquid-side volumetric mass transfer coefficient(kla)in a pilot-scale JBR was provided which can be applied to the design and scale-up of JBRs.展开更多
Mass transfer at hydrogen evolving mercury electrode has been studied by determining mass transfer coefficients of indicator ions as the function of current density of hydrogen evolution for various kinds of indica to...Mass transfer at hydrogen evolving mercury electrode has been studied by determining mass transfer coefficients of indicator ions as the function of current density of hydrogen evolution for various kinds of indica tor ions in sulphuric acid solution.Mercury adhering to metal substrates of Ni,Cu or Ag is used as mercury electrode to overcome its trembling during the electrolysis.The effect of difTerent indicator ions,electrode character istic,substrate material,diameter of electrode and temperature is examined.It is found that the transfer coefficient is proportional to the mass square root of current density of hydrogen evolution.展开更多
1 INTRODUCTIONIt is well known that the throughput of many gas-liquid reactors is limited by the rate atwhich a gaseous component can be transferred from the gas to the liquid.For example,it isthe oxygen transfer capa...1 INTRODUCTIONIt is well known that the throughput of many gas-liquid reactors is limited by the rate atwhich a gaseous component can be transferred from the gas to the liquid.For example,it isthe oxygen transfer capacity of a fermentor that set the upper limit to the productivity ofmost aerobic fermentation.Therefore,studies have been in progress to increase the masstransfer rate between the gas bubble and the broth by acting on classical parameters of bubblesize and the turbulence of flow.However,the intensive turbulence of flow usually展开更多
The new method of in-situ desulfurization with mechanical stirring of new type impellers was introduced, in which the bubble＇s dispersion and disintegration of magnesium vapor were the key to boosting the desulfuriza...The new method of in-situ desulfurization with mechanical stirring of new type impellers was introduced, in which the bubble＇s dispersion and disintegration of magnesium vapor were the key to boosting the desulfurization efficiency and increasing the utilization rate of magnesium. Effects of different new type of impellers on bubble dis persion and disintegration were studied through bubble image analysis, gas-liquid mass transfer, and power con- sumption levels of different impeller structures. The results showed that the sloped swept-back blade impeller-2 pro- duces optimal bubble＇s dispersion and disintegration, as well as higher volumetric mass transfer coefficient and CO2 gas utilization while consuming the least power. Numerical simulation result with Fluent software also showed that the sloped swept-back blade impeller-2 has higher turbulent kinetic energy and better velocity distribution than the other two impellers.展开更多
文摘Experiments have been done on mass transfer to a liquid-liquid interface on which inert gas bubbles are sparged.To simulate the pyrometallurgy system of melten slag-metal(or matte),aqueous solution-mercury(or zinc amalgam) system was used.The mass transfer coefficients of indicator ions as a function of bubble parameters have been determined.The experimental results show satisfactory agreement with the mass transfer model proposed Previously.
文摘Danckwert’s method was used to determine the specific interfacial area, a, and the individual mass transfer coefficient, kL, during absorption of CO2 in a bubble column with an anionic surfactant in the carbonate-bicarbonate buffer solution and NaAsO2 as catalyst, the presence of which decreases the specific interfacial area and the individual mass transfer coefficient. The specific interfacial area and the individual mass transfer coefficient increase with increasing su- perficial gas velocity. The specific interfacial area decreases whereas the individual mass transfer coefficient increases with increasing temperature. The results of experiments were used to determine the dependence of a, kL, and kLa on the surface tension, the temperature of the absorption phase, and the superficial velocity of the gas. The calculated results from the correlation were found to be within 10% deviation from the actual experimental results.
基金the authors appreciate the vice-chancellor of research and technology of the University of Isfahan for supporting this work under Grant No.911401707。
文摘The hydrodynamics and mass transfer characteristics of a lab-scale jet bubbling reactor(JBR)including the gas holdup,volumetric mass transfer coefficient and specific interfacial area were assessed experimentally investigating the influence of temperature,pH and superficial gas velocity.The reactor diameter and height were 11 and 30 cm,respectively.It was equipped with a single sparger,operating at atmospheric pressure,20 and 40℃,and two pH values of 3 and 6.The height of the liquid was 23 cm,while the superficial gas velocity changed within 0.010-0.040 m·s^(-1)range.Experiments were conducted with pure oxygen as the gas phase and saturated lime solution as the liquid phase.The liquid-side volumetric mass transfer coefficient was determined under unsteady-state oxygen absorption in a saturated lime solution.The gas holdup was calculated based on the liquid height change,while the specific interfacial area was obtained by a physical method based on the bubble size distribution(BSD)in different superficial gas velocities.The results indicated that at the same temperature but different pH,the gas holdup variation was negligible,while the liquid-side volumetric mass transfer coefficient at the pH value of 6 was higher than that at the pH=3.At a constant pH but different temperatures,the gas holdup and the liquid-side volumetric mass transfer coefficients at 40℃were higher than that of the same at 20℃.A reasonable and appropriate estimation of the liquid-side volumetric mass transfer coefficient(kla)in a pilot-scale JBR was provided which can be applied to the design and scale-up of JBRs.
基金supported by the Foundation of the State Education Commission for doctoral students
文摘Mass transfer at hydrogen evolving mercury electrode has been studied by determining mass transfer coefficients of indicator ions as the function of current density of hydrogen evolution for various kinds of indica tor ions in sulphuric acid solution.Mercury adhering to metal substrates of Ni,Cu or Ag is used as mercury electrode to overcome its trembling during the electrolysis.The effect of difTerent indicator ions,electrode character istic,substrate material,diameter of electrode and temperature is examined.It is found that the transfer coefficient is proportional to the mass square root of current density of hydrogen evolution.
文摘1 INTRODUCTIONIt is well known that the throughput of many gas-liquid reactors is limited by the rate atwhich a gaseous component can be transferred from the gas to the liquid.For example,it isthe oxygen transfer capacity of a fermentor that set the upper limit to the productivity ofmost aerobic fermentation.Therefore,studies have been in progress to increase the masstransfer rate between the gas bubble and the broth by acting on classical parameters of bubblesize and the turbulence of flow.However,the intensive turbulence of flow usually
基金Item Sponsored by National Natural Science Foundation of China(50974035,51074047)High Technology Research and Development Program of China(2010AA03A405,2012AA062303)Innovation Team Project of Provincial Science and Technology of Liaoning Province of China(LT2010034)
文摘The new method of in-situ desulfurization with mechanical stirring of new type impellers was introduced, in which the bubble＇s dispersion and disintegration of magnesium vapor were the key to boosting the desulfurization efficiency and increasing the utilization rate of magnesium. Effects of different new type of impellers on bubble dis persion and disintegration were studied through bubble image analysis, gas-liquid mass transfer, and power con- sumption levels of different impeller structures. The results showed that the sloped swept-back blade impeller-2 pro- duces optimal bubble＇s dispersion and disintegration, as well as higher volumetric mass transfer coefficient and CO2 gas utilization while consuming the least power. Numerical simulation result with Fluent software also showed that the sloped swept-back blade impeller-2 has higher turbulent kinetic energy and better velocity distribution than the other two impellers.
