چكيده به لاتين
In this thesis, the behavior of hydrodynamic and mass transfer of a pilot plant horizontal-vertical pulsed sieve plate extraction column has been investigated in the process of extracting uranium from uranyl nitrate solution by 30% (v/v) tri-butyl phosphate (TBP)/ kerosene. Pulsed columns are designed and built in two vertical and horizontal structures. The problem of the high height of the industrial example of the vertical column, as well as the low capacity of the horizontal column due to the lack of buoyancy force, has caused the third horizontal-vertical structure (L-Shaped) to be considered, and by combining them, it is possible to take advantage of the advantages of both structures and cover their disadvantages. gave With this work, the high height of the industrial sample is reduced by making a part of it horizontal, and the capacity of the horizontal part is also increased due to the suction force created at the connection point of the two parts. In order to investigate hydrodynamic parameters comprehensively, In addition to the uranyl nitrate chemical system, four other chemical systems with different interfacial tension under conditions without mass transfer, including water- Kerosene, nitric acid- (5% (v/v)) TBP/ Kerosene, nitric acid-(15% (v/v)) TBP/ Kerosene and nitric acid-(30% (v/v)) TBP/Kerosene was tested. The investigated parameters include droplet size, droplet size distribution, dispersed phase holdup, sliding velocity, overall volumetric coefficient of mass transfer, and axial dispersion coefficients of continuous and dispersed phase, which by changing operational parameters such as pulsation intensity, volumetric flow rate of dispersed and continuous phases have been subject to sensitivity analysis. Experimental observations show that the pulsation intensity has the greatest impact on the behavior of the studied parameters, so that its increase, while reducing the droplet size by 55%, increases the intensity of mass transfer by 66%. Also, increasing the pulsation intensity leads to a decrease in the amount of dispersed phase hold up to 47% in both parts of the column. Dispersed phase flow rate has a greater effect on dispersed phase holdup than continuous phase flow rate. In order to determine the mass transfer coefficients, phase flows have been modeled with the help of three models of plug flow, axial mixing and forward mixing, and the axial mixing and forward mixing models provided far more accurate results than the plug flow model. So the average error of the prediction of the concentration distribution of the transported component along the length of the column for the axial mixing and forward mixing model is less than 10%, while the same error for the plug flow model is less than 30%. In addition, the results showed that increasing the operating parameters increases the overall volumetric coefficient of mass transfer. The axial dispersion coefficients of the continuous and dispersed phase are strongly affected by the pulsation intensity, and the axial dispersion coefficient of the continuous phase is significantly higher than the axial dispersion coefficient of the dispersed phase. Finally, by dimensional analysis and relational dimensionless numbers in order to predict hydrodynamic parameters and mass transfer coefficients based on each of the mass transfer models in the horizontal-vertical pulsed sieve plate extraction column, it is suggested that with an average absolute relative error less than 10% show a good agreement with the experimental data.
