In this paper, the measurement of liquid mixing in a downcomer of segmental type of distillation column is presented. The extent of liquid mixing is calculated by means of a mixing pool model. The results indicate tha...In this paper, the measurement of liquid mixing in a downcomer of segmental type of distillation column is presented. The extent of liquid mixing is calculated by means of a mixing pool model. The results indicate that liquid mixing in a downcomer is actually incomplete. It is a significant correction to the assumption of complete downcomer mixing or no downcomer mixing which is generally adopted in many distillation calculations. Besides, the present results are used in a two dimensional eddy diffusion model to calculate the distillation tray efficiency. It is shown that the assumption of complete downcomer mixing is closer to the actual situation than that of no downcomer mixing.展开更多
Experiments demonstrated that the weeping is mal-distributed andoccurs mainly in a region of tray deck next to the inlet weir. Theamount of weeping in this region depends on the weeping rate. On thisbasis, three types...Experiments demonstrated that the weeping is mal-distributed andoccurs mainly in a region of tray deck next to the inlet weir. Theamount of weeping in this region depends on the weeping rate. On thisbasis, three types of weeping distribution are proposed. The effectof mal-distributed weeping on the Murphree tray efficiency isevaluated by using the three-dimensional non-equilibrium mixing poolmodel, where the influences of the flow pattern and the variation ofMurphree pint efficiency on a tray are taken into account.展开更多
A new empirical correlation has been presented for the effect of entrainment on distillation tray efficiency based on the results of numerical solution given by Lockett, et al. The calculated results are in good agree...A new empirical correlation has been presented for the effect of entrainment on distillation tray efficiency based on the results of numerical solution given by Lockett, et al. The calculated results are in good agreement with those of the numerical solution given by Lockett, et al. The average deviation is 1.14% and the maximum deviation is 4.76% for the ranges of 0 〈 Pe ≤ 1000, 0.40 ≤ EOG ≤ 1.00, 0.5≤λ0 ≤ 3.0 and e0 ≤ 0.3. In comparison with the correlation proposed by Bennett et al., the average and maximum deviations of EM^av are 2.17% and 20.49%, respectively.展开更多
The jet co-flow packing tray(JCPT) with three different types of perforation in equal opening fraction was tested in two rectangular columns with 0.12m in width and 0.27m in length operated with air-water system. The ...The jet co-flow packing tray(JCPT) with three different types of perforation in equal opening fraction was tested in two rectangular columns with 0.12m in width and 0.27m in length operated with air-water system. The influences of gas phase orifice F-factor and clear liquid height Hc on the amount of liquid lifted, Q, were examined. The corresponding correlation between Q with F-factor and equivalent diameter of perforated holes as well as Hc was obtained. Furthermore, the non-steady state mass transfer performance of JCPT was tested by the humidification of air with water. Finally, by the analysis of data and comparison, it was found that the JCPT tray with single cap and two holes exhibited the highest mass transfer efficiency and best performance.展开更多
A computational mass transfer model is proposed for predicting the concentration profile and Murphree efficiency of sieve tray distillation column. The proposed model is based on using modified c＇2 -εc＇ two equatio...A computational mass transfer model is proposed for predicting the concentration profile and Murphree efficiency of sieve tray distillation column. The proposed model is based on using modified c＇2 -εc＇ two equations formulation for closing the differential turbulent mass transfer equation with improvement by considering the vapor injected from the sieve hole to be three dimensional. The predicted concentration distributions by using proposed model were checked by experimental work conducted on a sieve tray simulator of 1.2 meters in diameter for desorbing the dissolved oxygen in the feed water by blowing air. The model predictions were confirmed by the experimental measurement. The validation of the proposed model was further tested by comparing the simulated result with the performance of an industrial scale sieve tray distillation column reported by Kunesh et al. for the stripping of toluene from its water solution. The predicted outlet concentration of each tray and the Murphree tray efficiencies under different operating conditions were in agreement with the published data. The simulated turbulent mass transfer diffusivity on each tray was within the range of the experimental result in the same sieve column reported by Cai et al. In addition, the prediction of the influence of sieve tray structure on the tray efficiency by using the proposed model was demonstrated.展开更多
The application of the non equilibrium stage model to the multicomponent, non ideal liquid liquid extraction process is described in this paper. Pilot plant experiments and a commercial process of aromatic separati...The application of the non equilibrium stage model to the multicomponent, non ideal liquid liquid extraction process is described in this paper. Pilot plant experiments and a commercial process of aromatic separation by sulfolane in sieve tray extraction columns were chosen as examples to show the advantages and benefits of the non equilibrium stage model over the conventional model.展开更多
文摘In this paper, the measurement of liquid mixing in a downcomer of segmental type of distillation column is presented. The extent of liquid mixing is calculated by means of a mixing pool model. The results indicate that liquid mixing in a downcomer is actually incomplete. It is a significant correction to the assumption of complete downcomer mixing or no downcomer mixing which is generally adopted in many distillation calculations. Besides, the present results are used in a two dimensional eddy diffusion model to calculate the distillation tray efficiency. It is shown that the assumption of complete downcomer mixing is closer to the actual situation than that of no downcomer mixing.
文摘Experiments demonstrated that the weeping is mal-distributed andoccurs mainly in a region of tray deck next to the inlet weir. Theamount of weeping in this region depends on the weeping rate. On thisbasis, three types of weeping distribution are proposed. The effectof mal-distributed weeping on the Murphree tray efficiency isevaluated by using the three-dimensional non-equilibrium mixing poolmodel, where the influences of the flow pattern and the variation ofMurphree pint efficiency on a tray are taken into account.
基金Project supported by the National Natural Science Foundation of China(Grant No.10271074)
文摘A new empirical correlation has been presented for the effect of entrainment on distillation tray efficiency based on the results of numerical solution given by Lockett, et al. The calculated results are in good agreement with those of the numerical solution given by Lockett, et al. The average deviation is 1.14% and the maximum deviation is 4.76% for the ranges of 0 〈 Pe ≤ 1000, 0.40 ≤ EOG ≤ 1.00, 0.5≤λ0 ≤ 3.0 and e0 ≤ 0.3. In comparison with the correlation proposed by Bennett et al., the average and maximum deviations of EM^av are 2.17% and 20.49%, respectively.
文摘The jet co-flow packing tray(JCPT) with three different types of perforation in equal opening fraction was tested in two rectangular columns with 0.12m in width and 0.27m in length operated with air-water system. The influences of gas phase orifice F-factor and clear liquid height Hc on the amount of liquid lifted, Q, were examined. The corresponding correlation between Q with F-factor and equivalent diameter of perforated holes as well as Hc was obtained. Furthermore, the non-steady state mass transfer performance of JCPT was tested by the humidification of air with water. Finally, by the analysis of data and comparison, it was found that the JCPT tray with single cap and two holes exhibited the highest mass transfer efficiency and best performance.
基金Supported by the National lqatural Science Foundation of China （20736005）.
文摘A computational mass transfer model is proposed for predicting the concentration profile and Murphree efficiency of sieve tray distillation column. The proposed model is based on using modified c＇2 -εc＇ two equations formulation for closing the differential turbulent mass transfer equation with improvement by considering the vapor injected from the sieve hole to be three dimensional. The predicted concentration distributions by using proposed model were checked by experimental work conducted on a sieve tray simulator of 1.2 meters in diameter for desorbing the dissolved oxygen in the feed water by blowing air. The model predictions were confirmed by the experimental measurement. The validation of the proposed model was further tested by comparing the simulated result with the performance of an industrial scale sieve tray distillation column reported by Kunesh et al. for the stripping of toluene from its water solution. The predicted outlet concentration of each tray and the Murphree tray efficiencies under different operating conditions were in agreement with the published data. The simulated turbulent mass transfer diffusivity on each tray was within the range of the experimental result in the same sieve column reported by Cai et al. In addition, the prediction of the influence of sieve tray structure on the tray efficiency by using the proposed model was demonstrated.
文摘The application of the non equilibrium stage model to the multicomponent, non ideal liquid liquid extraction process is described in this paper. Pilot plant experiments and a commercial process of aromatic separation by sulfolane in sieve tray extraction columns were chosen as examples to show the advantages and benefits of the non equilibrium stage model over the conventional model.
