Under the presupposition of plug flow with dispersion, the partial differential equation (s.eq.3) for two-dimension (radial and axial) dispersion in a pulsed extraction column is deduced. Under the condition of pulse ...Under the presupposition of plug flow with dispersion, the partial differential equation (s.eq.3) for two-dimension (radial and axial) dispersion in a pulsed extraction column is deduced. Under the condition of pulse input of tracer at the center of the column, the mathematical solution for eq.3 is found and given in this paper, that is,the mathematical model for two-dimension dispersion (s.eq.4). This mathematical model corresponds to the measured experimental data (s. Fig.3). With the Marquardt method for minimization of sum of square of errors between model and experimental data, the radial dispersion coefficient and axial dispersion coefficient could be determined at the same time.展开更多
A study on two-phase flow characteristics in a coalescence-dispersion pulsed-sieve-plate extraction column of 150mm in diameter was carried out with a working system of 30% tri-butyl-phosphate (TBP) (in kerosene)-nitr...A study on two-phase flow characteristics in a coalescence-dispersion pulsed-sieve-plate extraction column of 150mm in diameter was carried out with a working system of 30% tri-butyl-phosphate (TBP) (in kerosene)-nitric acid-water. The influence of operation conditions on the holdup of the dispersed phase was investigated. According to the analysis of the experimental data, there was a turning point on the curve of ln(Vs) versus ln(l-Φ) under certain pulse intensity. When the holdup is higher than the value at the turning point, the two-phase flow characteristics can be described with the modified Pratt's equation, otherwise a new relation in the form ofΦ=1/2.75uk(uc + 4ud) may be used, which is proposed by this study.展开更多
A new configuration of coalescence-dispersed pulsed-sieve-plate extraction column (CDPSEC) was developed, and the mass transfer and axial mixing characteristics were evaluated with the two-point dynamic method.The inf...A new configuration of coalescence-dispersed pulsed-sieve-plate extraction column (CDPSEC) was developed, and the mass transfer and axial mixing characteristics were evaluated with the two-point dynamic method.The influence of operation conditions was discussed with experimental results, showing that the mass transfer performance of CDPSEC mainly depends on the energy input and the holdup of dispersed phase. Higher energy input results in higher holdup of the dispersed phase, the axial mixing of the continuous phase is suppressed, and the true height of mass transfer unit decreases markedly. On the other hand, higher energy input leads to more serious forward mixing of the dispersed phase, so the energy input should be limited. Accordingly the operation conditions were divided into two regions, and empirical correlations for predicting the mass transfer and axial mixing characteristics in different regions with a satisfactory accuracy were suggested.展开更多
Liquid-liquid equilibrium (LLE) data of water-caprolactam-benzene-(NH4)2SO4 system at 303 K were measured for extraction of caprolactam from aqueous ammonium sulfate solution. The influence of fluid flow rate, pulsati...Liquid-liquid equilibrium (LLE) data of water-caprolactam-benzene-(NH4)2SO4 system at 303 K were measured for extraction of caprolactam from aqueous ammonium sulfate solution. The influence of fluid flow rate, pulsation intensity on flooding velocity and mass transfer was studied for extraction of caprolactam from ammonium sulfate solution in a laboratory pulsed packed column. The flooding velocities and overall apparent height of a transfer unit were given under various operation conditions. An industrial column developed based on above study is operated well. The scale-up effect is discussed.展开更多
Using experimental data from a number of pulsed disc and doughnut solvent extraction columns, a unified correla- tion for the prediction of dispersed phase holdup that considers the effects of mass transfer is present...Using experimental data from a number of pulsed disc and doughnut solvent extraction columns, a unified correla- tion for the prediction of dispersed phase holdup that considers the effects of mass transfer is presented. Pulsed disc and doughnut solvent extraction columns （PDDC） have been used for a range of important applications such as ura- nium extraction and nuclear fuel recycling. Although the dispersed phase holdup in a PDDC has been presented by some researchers, there is still the need to develop a robust correlation that can predict the experimental dispersed phase holdup over a range of operating conditions including the effects of mass transfer direction. In this study, dis- persed phase holdup data from different literature sources for a PDDC were used to refit constants for the correlation presented by Kumar and Hartland lind. Eng. Chem. Res.,27 （1988）,131-138] which did not consider the effect of col- umn geometry. In order to incorporate the characteristic length of the PDDC （i.e. the plate spacing）, the unified cor- relation for holdup proposed by Kumar and Hartland based on data from eight different types of columns [Ind. Eng. Chem. Res.,34 （1995） 3925-3940] was refitted to the PDDC data. New constants have been presented for each hold- up correlation for a PDDC based on regression analysis using published holdup data from PDDCs that cover a range of onerating conditions and nhwical nronerties and consider the direction of mass transfer.展开更多
文摘Under the presupposition of plug flow with dispersion, the partial differential equation (s.eq.3) for two-dimension (radial and axial) dispersion in a pulsed extraction column is deduced. Under the condition of pulse input of tracer at the center of the column, the mathematical solution for eq.3 is found and given in this paper, that is,the mathematical model for two-dimension dispersion (s.eq.4). This mathematical model corresponds to the measured experimental data (s. Fig.3). With the Marquardt method for minimization of sum of square of errors between model and experimental data, the radial dispersion coefficient and axial dispersion coefficient could be determined at the same time.
基金Supported by the National Natural Science Foundation of China (No. 29236122).
文摘A study on two-phase flow characteristics in a coalescence-dispersion pulsed-sieve-plate extraction column of 150mm in diameter was carried out with a working system of 30% tri-butyl-phosphate (TBP) (in kerosene)-nitric acid-water. The influence of operation conditions on the holdup of the dispersed phase was investigated. According to the analysis of the experimental data, there was a turning point on the curve of ln(Vs) versus ln(l-Φ) under certain pulse intensity. When the holdup is higher than the value at the turning point, the two-phase flow characteristics can be described with the modified Pratt's equation, otherwise a new relation in the form ofΦ=1/2.75uk(uc + 4ud) may be used, which is proposed by this study.
文摘A new configuration of coalescence-dispersed pulsed-sieve-plate extraction column (CDPSEC) was developed, and the mass transfer and axial mixing characteristics were evaluated with the two-point dynamic method.The influence of operation conditions was discussed with experimental results, showing that the mass transfer performance of CDPSEC mainly depends on the energy input and the holdup of dispersed phase. Higher energy input results in higher holdup of the dispersed phase, the axial mixing of the continuous phase is suppressed, and the true height of mass transfer unit decreases markedly. On the other hand, higher energy input leads to more serious forward mixing of the dispersed phase, so the energy input should be limited. Accordingly the operation conditions were divided into two regions, and empirical correlations for predicting the mass transfer and axial mixing characteristics in different regions with a satisfactory accuracy were suggested.
文摘Liquid-liquid equilibrium (LLE) data of water-caprolactam-benzene-(NH4)2SO4 system at 303 K were measured for extraction of caprolactam from aqueous ammonium sulfate solution. The influence of fluid flow rate, pulsation intensity on flooding velocity and mass transfer was studied for extraction of caprolactam from ammonium sulfate solution in a laboratory pulsed packed column. The flooding velocities and overall apparent height of a transfer unit were given under various operation conditions. An industrial column developed based on above study is operated well. The scale-up effect is discussed.
文摘Using experimental data from a number of pulsed disc and doughnut solvent extraction columns, a unified correla- tion for the prediction of dispersed phase holdup that considers the effects of mass transfer is presented. Pulsed disc and doughnut solvent extraction columns （PDDC） have been used for a range of important applications such as ura- nium extraction and nuclear fuel recycling. Although the dispersed phase holdup in a PDDC has been presented by some researchers, there is still the need to develop a robust correlation that can predict the experimental dispersed phase holdup over a range of operating conditions including the effects of mass transfer direction. In this study, dis- persed phase holdup data from different literature sources for a PDDC were used to refit constants for the correlation presented by Kumar and Hartland lind. Eng. Chem. Res.,27 （1988）,131-138] which did not consider the effect of col- umn geometry. In order to incorporate the characteristic length of the PDDC （i.e. the plate spacing）, the unified cor- relation for holdup proposed by Kumar and Hartland based on data from eight different types of columns [Ind. Eng. Chem. Res.,34 （1995） 3925-3940] was refitted to the PDDC data. New constants have been presented for each hold- up correlation for a PDDC based on regression analysis using published holdup data from PDDCs that cover a range of onerating conditions and nhwical nronerties and consider the direction of mass transfer.
