A computational fluid dynamics （CFD） simulation was carried out with CFX4,3 to investigate the melt flow and temperature distributions in the settler of a flash furnace. Sixteen cases of one slag tap hole adopted wi...A computational fluid dynamics （CFD） simulation was carried out with CFX4,3 to investigate the melt flow and temperature distributions in the settler of a flash furnace. Sixteen cases of one slag tap hole adopted with one matte tap hole （1-to-l） and one slag tap hole adopted with two matte tap holes （1-to-2） operation modes were modelled. The simulation results show that the melt flows are similar in both two operation modes, but evident circulations can be found in the case of the 1-to-2 operation mode. The combination modes of the slag and matte tap holes are found to have a significant effect on the temperature distributions of the melt. The melt temperature is more uniform in the case of the 1-to-2 mode. Selection of a matte tap hole farther away from the inlet is more conducive to achieve a uniform distribution of the melt temperature in the settler in nractical tannine oneration展开更多
Drop size distribution(DSD) or mean droplet size(d32) and liquid holdup are two key parameters in a liquid–liquid extraction process. Understanding and accurately predicting those parameters are of great importance i...Drop size distribution(DSD) or mean droplet size(d32) and liquid holdup are two key parameters in a liquid–liquid extraction process. Understanding and accurately predicting those parameters are of great importance in the optimal design of extraction columns as well as mixer–settlers. In this paper, the method of built-in endoscopic probe combined with pulse laser was adopted to measure the droplet size in liquid–liquid dispersions with a pump-impeller in a rectangular mixer. The dispersion law of droplets with holdup range 1% to 24% in batch process and larger flow ratio range 1/5 to 5/1 in continuous process was studied. Under the batch operation condition, the DSD abided by log-normal distribution. With the increase of impeller speed or decrease of dispersed phase holdup, the d32 decreased. In addition, a prediction model of d32 of kerosene/deionized system was established as d32/D = 0.13(1 + 5.9φ)We-0.6. Under the continuous operation condition, the general model for droplet size prediction of kerosene/water system was presented as d32/D = C3(1 + C4φ)We-0.6. For the surfactant system and extraction system, the prediction models met a general model as d32/D = bφnWe-0.6.展开更多
This work is aimed at optimizing a settler structure in a mixer-settler.Two different aspects have been considered.Firstly,the flowcharacteristics of a settler have been examined by computational fluid dynamics(CFD)si...This work is aimed at optimizing a settler structure in a mixer-settler.Two different aspects have been considered.Firstly,the flowcharacteristics of a settler have been examined by computational fluid dynamics(CFD)simulation with various agitation speeds of the mixer,as well as organic phase volume fractions ranging from 0.075 to 0.6.The aqueous and organic phase turbulent flow fields were measured by particle image velocimetry(PIV)technique to verify the CFD simulation.Two organic phases with different physical properties were assessed in the CFD simulation to simulate the liquid-liquid systems related to rare earth element extraction,i.e.,0.072 mol·L^-1 P507/kerosene and 1.8 mol·L^-1 P507/kerosene.Secondly,the CFD simulation was carried out in a settler equipped with baffles.The effects of number and location of the baffle in the settler on flow features and entrainments of the aqueous and organic outlet were analyzed.Meanwhile,different settler/mixer volume ratios were also examined.By analyses and comparisons,an optimal design for settler was proposed.CFD can provide a significant guidance to better mixer-settler design.展开更多
A novel purification process based on mixer-settlers for high-purity NdClwas developed. Acidic solution and pure NdClsolution were compared to scrub the less-extractable rare earths(REs)(La, Ce, and Pr)from loaded org...A novel purification process based on mixer-settlers for high-purity NdClwas developed. Acidic solution and pure NdClsolution were compared to scrub the less-extractable rare earths(REs)(La, Ce, and Pr)from loaded organic phase. The extractant with low-degree saponification was evaluated to remove the more-extractable element(Sm). Then the RE impurities(La, Ce, Pr, and Sm) in Nd were purified by an integrated process. Furthermore, effect of smuggling behavior on the purification of NdClin mixersettlers was studied. Based on the investigation mentioned above, the pilot-scale purification process for NdClwith a purity of 99.999% was developed, and the total recovery was about 99%.展开更多
The main ideas in the development of the solvent extraction mixer settler focused on achieving clean phase separation,minimizing the loss of the reagents and decreasing the surface area of the settlers.The role of baf...The main ideas in the development of the solvent extraction mixer settler focused on achieving clean phase separation,minimizing the loss of the reagents and decreasing the surface area of the settlers.The role of baffles in a mechanically agitated vessel is to ensure even distribution,reduce settler turbulence,promote the stability of power drawn by the impeller and to prevent swirling and vortexing of liquid,thus,greatly improving the mixing of liquid.The insertion of the appropriate number of baffles clearly improves the extent of liquid mixing.However,excessive baffling would interrupt liquid mixing and lengthen the mixing time.Computational fluid dynamics(CFD) provides a tool for determining detailed information on fluid flow(hydrodynamics) which is necessary for modeling subprocesses in mixer settler.A total of 54 final CFD runs were carried out representing different combinations of variables like number of baffles,density and impeller speed.CFD data shows that amount of separation increases with increasing baffles number and decreasing impeller speed.展开更多
By increasing particle concentration and G value （root-mean-square velocity gradient） to enhance flocculation, a novel vertical-flow settler was designed to increase sedimentation effectiveness, and to simultaneousl...By increasing particle concentration and G value （root-mean-square velocity gradient） to enhance flocculation, a novel vertical-flow settler was designed to increase sedimentation effectiveness, and to simultaneously improve operational stabilization. Due to the gradual decrease in upward flow-rate of raw water, a floes blanket would form and suspend in the middle section of the settler, not at the bottom as in a conventional clarifier. Enough large floes, resulted from flocculation or fltration, would continuously settle out of the floes blanket, and simultaneously, the floes in raw water or those forming above the blanket would ceaselessly enter the floes blanket. As a result, the floes concentration in the blanket could keep a dynamic balance. The hydrodynamic shear in the blanket was improved by flow separation, which was induced by the abrupt change in flow channel. Due to the floes blanket and improved hydrodynamic shear, flocculation would be enhanced, which was helpful for removing fine particles in raw water. A comparative study showed that the novel vertical-flow settler had a much better performance in the removal of the particles in raw water than a conventional one, when they treated kaolin suspensions of different concentrations （500, 100 and 50 mg/L, respectively） coagulated by polyaluminum chloride（PAC1） at the up-flow rates of 1 and 2 mm/s, respectively.展开更多
Settlers are broadly used by industries for separating components with different densities, because they show operational facilities and high efficiency. As they use the action of gravity, they can treat great quantit...Settlers are broadly used by industries for separating components with different densities, because they show operational facilities and high efficiency. As they use the action of gravity, they can treat great quantities of effluents with lower energy expenditure. However, the performance of the settler depends on the streamlines inside the equipment, which, in turn, are influenced by the characteristics of the suspended solids, the geometry, and dimensions of the tank. In this paper, the effect of the settler geometry properties on the hydrodynamic in a vertical circular cylindrical tank was investigated. The evaluated parameters were the feed pipe design, the dimensions of the piece of equipment, and the structure of settler bottom. The numerical simulations were performed using the package ANSYS-CFX 16.0. It was considered a turbulent, isothermal, and stationary flow. The Euler-Euler multiphase model and BSL-RSM model turbulence were applied. The recirculation zones were influenced by the separation tank geometrical form. The modification of the feed pipe in the original project reduced the mixture inside the feedwell. The increase of the sedimentation tank diameter improved the performance of water and solid separation, elevating the efficiency by 10.48%, whilst the increase of the tank depth reduced the separation efficiency by 16.72%, in comparison to the original project.展开更多
Myocardial injury is a common disease in the plateau,especially in the lowlanders who have migrated to the plateau,in which the pathogenesis is not well understood.Here,we established a cohort of lowlanders comprising...Myocardial injury is a common disease in the plateau,especially in the lowlanders who have migrated to the plateau,in which the pathogenesis is not well understood.Here,we established a cohort of lowlanders comprising individuals from both low-altitude and high-altitude areas and conducted plasma proteomic profiling.Proteomic data showed that there was a significant shift in energy metabolism and inflammatory response in individuals with myocardial abnormalities at high altitude.Notably,integrin alpha-Ⅱb(ITGA2B)emerged as a potential key player in this context.Functional studies demonstrated that ITGA2B upregulated the transcription and secretion of interleukin-6(IL-6)through the integrin-linked kinase(ILK)/nuclear factor-κB(NF-κB)signaling axis under hypoxic conditions.Moreover,ITGA2B disrupted mitochondrial structure and function,increased glycolytic capacity,and aggravated energy reprogramming from oxidative phosphorylation to glycolysis.Leveraging the therapeutic potential of traditional Chinese medicine in cardiac diseases,we discovered that tanshinoneⅡA(TanⅡA)effectively alleviated the myocardial injury caused by the abnormally elevated expression of ITGA2B and hypobaric hypoxia exposure in mice,thus providing a novel candidate therapeutic strategy for the prevention and treatment of high-altitude myocardial injury.展开更多
In wastewater treatment plants （WWTPs）, a secondary settler acts as a clarifier, sludge thickener, and sludge storage tank during peak flows and therefore plays an important role in the performance of the activated ...In wastewater treatment plants （WWTPs）, a secondary settler acts as a clarifier, sludge thickener, and sludge storage tank during peak flows and therefore plays an important role in the performance of the activated sludge process. Sludge thickening occurs in the lower portions of secondary clarifiers during their operation. In this study, by detecting the hindered zone from the complete thickening process of activated sludge, a simple model for the sludge thickening velocity, us = aXb （ a =0.9925SSFI3.5, b = - 3.5411n（ SS VI3.5 ） ＋12.973）, describing the potential and performance of activated sludge thickening in the hindered zone was developed. However, sludge thickening in the compression zone was not studied because sludge in the compression zone showed limited thickening. This empirical model was developed using batch settling data obtained from four WWTPs and validated using measured data from a fifth WWTP to better study sludge thickening. To explore different sludge settling and thickening mechanisms, the curves of sludge thickening and sludge settling were compared. Finally, it was found that several factors including temperature, stirring, initial depth, and polymer conditioning can lead to highly concentrated return sludge and biomass in a biologic reactor.展开更多
基金Project (2002AA00104) supported by the National High-tech Research and Development Program of China
文摘A computational fluid dynamics （CFD） simulation was carried out with CFX4,3 to investigate the melt flow and temperature distributions in the settler of a flash furnace. Sixteen cases of one slag tap hole adopted with one matte tap hole （1-to-l） and one slag tap hole adopted with two matte tap holes （1-to-2） operation modes were modelled. The simulation results show that the melt flows are similar in both two operation modes, but evident circulations can be found in the case of the 1-to-2 operation mode. The combination modes of the slag and matte tap holes are found to have a significant effect on the temperature distributions of the melt. The melt temperature is more uniform in the case of the 1-to-2 mode. Selection of a matte tap hole farther away from the inlet is more conducive to achieve a uniform distribution of the melt temperature in the settler in nractical tannine oneration
基金Supported by the National Natural Science Foundation of China(NSFC)(21636004)the National Safety Academy Foundation(U1530107)the National Basic Research Program of China(2012CBA01203).
文摘Drop size distribution(DSD) or mean droplet size(d32) and liquid holdup are two key parameters in a liquid–liquid extraction process. Understanding and accurately predicting those parameters are of great importance in the optimal design of extraction columns as well as mixer–settlers. In this paper, the method of built-in endoscopic probe combined with pulse laser was adopted to measure the droplet size in liquid–liquid dispersions with a pump-impeller in a rectangular mixer. The dispersion law of droplets with holdup range 1% to 24% in batch process and larger flow ratio range 1/5 to 5/1 in continuous process was studied. Under the batch operation condition, the DSD abided by log-normal distribution. With the increase of impeller speed or decrease of dispersed phase holdup, the d32 decreased. In addition, a prediction model of d32 of kerosene/deionized system was established as d32/D = 0.13(1 + 5.9φ)We-0.6. Under the continuous operation condition, the general model for droplet size prediction of kerosene/water system was presented as d32/D = C3(1 + C4φ)We-0.6. For the surfactant system and extraction system, the prediction models met a general model as d32/D = bφnWe-0.6.
基金the National Basic Research Program of China(No.2012CBA01203)National Natural Science Foundation of China(No.21636004)the Specialized Research Fund for Doctoral Program of Higher Education of MOE of China(No.20130002110018)in the State Key Laboratory of Chemical Engineering of Tsinghua University,Beijing,China。
文摘This work is aimed at optimizing a settler structure in a mixer-settler.Two different aspects have been considered.Firstly,the flowcharacteristics of a settler have been examined by computational fluid dynamics(CFD)simulation with various agitation speeds of the mixer,as well as organic phase volume fractions ranging from 0.075 to 0.6.The aqueous and organic phase turbulent flow fields were measured by particle image velocimetry(PIV)technique to verify the CFD simulation.Two organic phases with different physical properties were assessed in the CFD simulation to simulate the liquid-liquid systems related to rare earth element extraction,i.e.,0.072 mol·L^-1 P507/kerosene and 1.8 mol·L^-1 P507/kerosene.Secondly,the CFD simulation was carried out in a settler equipped with baffles.The effects of number and location of the baffle in the settler on flow features and entrainments of the aqueous and organic outlet were analyzed.Meanwhile,different settler/mixer volume ratios were also examined.By analyses and comparisons,an optimal design for settler was proposed.CFD can provide a significant guidance to better mixer-settler design.
基金Project supported by'Hundreds Talents Program' from Chinese Academy of Sciences,Science and Technology Major Project of Fujian Province(2015HZ0001-3)National Natural Science Foundation of China(21571179)Science and Technology Major Project of Ganzhou(2017-8)
文摘A novel purification process based on mixer-settlers for high-purity NdClwas developed. Acidic solution and pure NdClsolution were compared to scrub the less-extractable rare earths(REs)(La, Ce, and Pr)from loaded organic phase. The extractant with low-degree saponification was evaluated to remove the more-extractable element(Sm). Then the RE impurities(La, Ce, Pr, and Sm) in Nd were purified by an integrated process. Furthermore, effect of smuggling behavior on the purification of NdClin mixersettlers was studied. Based on the investigation mentioned above, the pilot-scale purification process for NdClwith a purity of 99.999% was developed, and the total recovery was about 99%.
文摘The main ideas in the development of the solvent extraction mixer settler focused on achieving clean phase separation,minimizing the loss of the reagents and decreasing the surface area of the settlers.The role of baffles in a mechanically agitated vessel is to ensure even distribution,reduce settler turbulence,promote the stability of power drawn by the impeller and to prevent swirling and vortexing of liquid,thus,greatly improving the mixing of liquid.The insertion of the appropriate number of baffles clearly improves the extent of liquid mixing.However,excessive baffling would interrupt liquid mixing and lengthen the mixing time.Computational fluid dynamics(CFD) provides a tool for determining detailed information on fluid flow(hydrodynamics) which is necessary for modeling subprocesses in mixer settler.A total of 54 final CFD runs were carried out representing different combinations of variables like number of baffles,density and impeller speed.CFD data shows that amount of separation increases with increasing baffles number and decreasing impeller speed.
基金The Hi-Tech Research and Development Program (863) of China (No. 2002AA601290 2003AA601010-03) and the NationalNatural Science Foundation of China (No. 50178067)
文摘By increasing particle concentration and G value （root-mean-square velocity gradient） to enhance flocculation, a novel vertical-flow settler was designed to increase sedimentation effectiveness, and to simultaneously improve operational stabilization. Due to the gradual decrease in upward flow-rate of raw water, a floes blanket would form and suspend in the middle section of the settler, not at the bottom as in a conventional clarifier. Enough large floes, resulted from flocculation or fltration, would continuously settle out of the floes blanket, and simultaneously, the floes in raw water or those forming above the blanket would ceaselessly enter the floes blanket. As a result, the floes concentration in the blanket could keep a dynamic balance. The hydrodynamic shear in the blanket was improved by flow separation, which was induced by the abrupt change in flow channel. Due to the floes blanket and improved hydrodynamic shear, flocculation would be enhanced, which was helpful for removing fine particles in raw water. A comparative study showed that the novel vertical-flow settler had a much better performance in the removal of the particles in raw water than a conventional one, when they treated kaolin suspensions of different concentrations （500, 100 and 50 mg/L, respectively） coagulated by polyaluminum chloride（PAC1） at the up-flow rates of 1 and 2 mm/s, respectively.
文摘Settlers are broadly used by industries for separating components with different densities, because they show operational facilities and high efficiency. As they use the action of gravity, they can treat great quantities of effluents with lower energy expenditure. However, the performance of the settler depends on the streamlines inside the equipment, which, in turn, are influenced by the characteristics of the suspended solids, the geometry, and dimensions of the tank. In this paper, the effect of the settler geometry properties on the hydrodynamic in a vertical circular cylindrical tank was investigated. The evaluated parameters were the feed pipe design, the dimensions of the piece of equipment, and the structure of settler bottom. The numerical simulations were performed using the package ANSYS-CFX 16.0. It was considered a turbulent, isothermal, and stationary flow. The Euler-Euler multiphase model and BSL-RSM model turbulence were applied. The recirculation zones were influenced by the separation tank geometrical form. The modification of the feed pipe in the original project reduced the mixture inside the feedwell. The increase of the sedimentation tank diameter improved the performance of water and solid separation, elevating the efficiency by 10.48%, whilst the increase of the tank depth reduced the separation efficiency by 16.72%, in comparison to the original project.
基金supported by the Innovation Team and Talents Cultivation Program of National Administration of Traditional Chinese Medicine(Grant No.ZYYCXTD-D-202207)the National Natural Science Foundation of China(Grant No.82204774).
文摘Myocardial injury is a common disease in the plateau,especially in the lowlanders who have migrated to the plateau,in which the pathogenesis is not well understood.Here,we established a cohort of lowlanders comprising individuals from both low-altitude and high-altitude areas and conducted plasma proteomic profiling.Proteomic data showed that there was a significant shift in energy metabolism and inflammatory response in individuals with myocardial abnormalities at high altitude.Notably,integrin alpha-Ⅱb(ITGA2B)emerged as a potential key player in this context.Functional studies demonstrated that ITGA2B upregulated the transcription and secretion of interleukin-6(IL-6)through the integrin-linked kinase(ILK)/nuclear factor-κB(NF-κB)signaling axis under hypoxic conditions.Moreover,ITGA2B disrupted mitochondrial structure and function,increased glycolytic capacity,and aggravated energy reprogramming from oxidative phosphorylation to glycolysis.Leveraging the therapeutic potential of traditional Chinese medicine in cardiac diseases,we discovered that tanshinoneⅡA(TanⅡA)effectively alleviated the myocardial injury caused by the abnormally elevated expression of ITGA2B and hypobaric hypoxia exposure in mice,thus providing a novel candidate therapeutic strategy for the prevention and treatment of high-altitude myocardial injury.
文摘In wastewater treatment plants （WWTPs）, a secondary settler acts as a clarifier, sludge thickener, and sludge storage tank during peak flows and therefore plays an important role in the performance of the activated sludge process. Sludge thickening occurs in the lower portions of secondary clarifiers during their operation. In this study, by detecting the hindered zone from the complete thickening process of activated sludge, a simple model for the sludge thickening velocity, us = aXb （ a =0.9925SSFI3.5, b = - 3.5411n（ SS VI3.5 ） ＋12.973）, describing the potential and performance of activated sludge thickening in the hindered zone was developed. However, sludge thickening in the compression zone was not studied because sludge in the compression zone showed limited thickening. This empirical model was developed using batch settling data obtained from four WWTPs and validated using measured data from a fifth WWTP to better study sludge thickening. To explore different sludge settling and thickening mechanisms, the curves of sludge thickening and sludge settling were compared. Finally, it was found that several factors including temperature, stirring, initial depth, and polymer conditioning can lead to highly concentrated return sludge and biomass in a biologic reactor.
