Axial mixing coefficients in gas phase under nitrogen-water two-phase flow conditions at high pressure were measured in a packed column (0.15?m diameter,8.4?m high, with a 2.1?m packed section) by the technique of pul...Axial mixing coefficients in gas phase under nitrogen-water two-phase flow conditions at high pressure were measured in a packed column (0.15?m diameter,8.4?m high, with a 2.1?m packed section) by the technique of pulse injection of hydrogen. The packing was 350?Y Mellapak, manufactured by the Tianjin UnivTech Co. Ltd.. Nitrogen and water flowed countercurrently through the column at gas rates from 0.03 to 0.15?m·s -1 ,and liquid rates from 17.0 to 75.0?m 3·m -2 ·h -1 . The operation pressure varied from 0.10 to 1.70?MPa.The hydrogen concentration in gas phase was detected continuously by means of thermal conductivity. The one dimensional diffusion model was used for smoothing the experimental response curves with 7 per cent average errors. The experimental data showed that the axial mixing coefficient in gas increased with the increase of the interstitial velocity and the operation pressure. This trend may be due to the increase of the density and the viscosity of the nitrogen under high pressure. Practically no effect of the water loading on the axial mixing coefficient was observed.展开更多
Experiments were conducted in the high pressure distillation column containing corrugated structured packing of Mellapak 250Y under operating pressure from 0.3 MPa to 2 MPa, using n -butane and n -pentane mixture as t...Experiments were conducted in the high pressure distillation column containing corrugated structured packing of Mellapak 250Y under operating pressure from 0.3 MPa to 2 MPa, using n -butane and n -pentane mixture as the separating material. The height equivalent to a theoretical plate (HETP) was evaluated from the measured n -butane liquid concentration profile along the packing. After carefully analyzed, the HETP may be reasonably divided into two parts. The first part is the ideal height of mass transfer unit, which is caused by the mass transfer resistance between vapor and liquid. Another part is the height of backmixing unit (HBU), which is caused by the backmixing of vapor and liquid. The parameters of HBU correlation were evaluated by the experimental data. The present HETP correlation was used to predict the experimental results in literature, and well agreement was found between them.展开更多
The separation efficiency of a representative sheet metal structured packing (Mellapak 350Y) in experimental columns (0.15?m i.d.) is presented at high-pressure and total reflux distillation conditions. N -butane and ...The separation efficiency of a representative sheet metal structured packing (Mellapak 350Y) in experimental columns (0.15?m i.d.) is presented at high-pressure and total reflux distillation conditions. N -butane and n -pentane is used as the testing system.Pressures span the range of 0.7-1.9?MPa.With the increase of F -factor,the HETP values decrease slightly in the loading area at all test pressure but increase before flooding point.By comparing the experiment data with the predictions of SRP model,it is found that SRP model performance deteriorates at a high pressure.展开更多
The vapor phase passing through the flowing liquid on a distillation tray exerts a resisting force on the liquid phase and,at the same time,enhances liquid turbulence.Both of these effects should be considered in the ...The vapor phase passing through the flowing liquid on a distillation tray exerts a resisting force on the liquid phase and,at the same time,enhances liquid turbulence.Both of these effects should be considered in the modeling of the Liquid velocity field.A mathematical model considering both effects isdeveloped.The comparison of the computed results with experiments shows that the proposed model is more suitable for simulating the velocity field on distillation trays than existing model.展开更多
文摘Axial mixing coefficients in gas phase under nitrogen-water two-phase flow conditions at high pressure were measured in a packed column (0.15?m diameter,8.4?m high, with a 2.1?m packed section) by the technique of pulse injection of hydrogen. The packing was 350?Y Mellapak, manufactured by the Tianjin UnivTech Co. Ltd.. Nitrogen and water flowed countercurrently through the column at gas rates from 0.03 to 0.15?m·s -1 ,and liquid rates from 17.0 to 75.0?m 3·m -2 ·h -1 . The operation pressure varied from 0.10 to 1.70?MPa.The hydrogen concentration in gas phase was detected continuously by means of thermal conductivity. The one dimensional diffusion model was used for smoothing the experimental response curves with 7 per cent average errors. The experimental data showed that the axial mixing coefficient in gas increased with the increase of the interstitial velocity and the operation pressure. This trend may be due to the increase of the density and the viscosity of the nitrogen under high pressure. Practically no effect of the water loading on the axial mixing coefficient was observed.
文摘Experiments were conducted in the high pressure distillation column containing corrugated structured packing of Mellapak 250Y under operating pressure from 0.3 MPa to 2 MPa, using n -butane and n -pentane mixture as the separating material. The height equivalent to a theoretical plate (HETP) was evaluated from the measured n -butane liquid concentration profile along the packing. After carefully analyzed, the HETP may be reasonably divided into two parts. The first part is the ideal height of mass transfer unit, which is caused by the mass transfer resistance between vapor and liquid. Another part is the height of backmixing unit (HBU), which is caused by the backmixing of vapor and liquid. The parameters of HBU correlation were evaluated by the experimental data. The present HETP correlation was used to predict the experimental results in literature, and well agreement was found between them.
文摘The separation efficiency of a representative sheet metal structured packing (Mellapak 350Y) in experimental columns (0.15?m i.d.) is presented at high-pressure and total reflux distillation conditions. N -butane and n -pentane is used as the testing system.Pressures span the range of 0.7-1.9?MPa.With the increase of F -factor,the HETP values decrease slightly in the loading area at all test pressure but increase before flooding point.By comparing the experiment data with the predictions of SRP model,it is found that SRP model performance deteriorates at a high pressure.
文摘The vapor phase passing through the flowing liquid on a distillation tray exerts a resisting force on the liquid phase and,at the same time,enhances liquid turbulence.Both of these effects should be considered in the modeling of the Liquid velocity field.A mathematical model considering both effects isdeveloped.The comparison of the computed results with experiments shows that the proposed model is more suitable for simulating the velocity field on distillation trays than existing model.
