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Study of Effects of Operational Parameters on Flooding in Pertraction of Dysprosium in a Vertical Pulsed Packed Column

Sadelari, Farzin | 2021

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 53766 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Bastani, Dariush; Safdari, Jaber; Raji, Maliheh
  7. Abstract:
  8. Pulsed packed columns are among the most important devices used in liquid-liquid extraction, with wide application in petroleum and petrochemical industries, metal salt extraction, pharmaceutical industries, metallurgy, and other areas. Liquid-membrane technology is an alternative separation technique to the liquid-liquid extraction for the extraction and recovery of metal ions from aqueous solutions. There are three main types of liquid membranes: emulsion liquid membrane (ELM), Bulk Liquid Membrane (BLM), and Supported Liquid Membrane (SLM). Liquid emulsion membrane is one of the pertraction methods with phase dispersion. It is a three-phase dispersion system, consisting: external phase, membrane, and internal or stripping phase in the form of a double emulsion. The solutes from the external phase are transported to the internal phase through the membrane phase. The membrane phase is usually an organic phase containing a carrier (extractant) and a surfactant to stabilize the primary emulsion droplet. The primary emulsion is made by dispersing the internal phase in the membrane phase. This emulsion is then dispersed into the external phase by agitation for extraction. In this study, Dysprosium was continuously extracted by an emulsion liquid membrane (ELM) using D2EHPA as a carrier and Span80 as a surfactant in a vertical Pulsed packed column. The optimum conditions for extraction and striping of Dysprosium in a vertical Pulsed packed column were determined. Furthermore, the effect of operational parameters such as continuous phase flow rate, dispersed phase flow rate, and pulsation intensity on flooding points was evaluated. Average extraction and stripping efficiency of 99.76 % and 77.89% was obtained using 1M HNO3 as stripping solution under the optimum conditions, which verified the possibility of applying the extraction of D(III) using an ELM to a continuous process in a pulsed packed column. The results showed that the maximum throughput decreases with the increase in pulsation intensity and flow ratio. Increasing the continuous phase flow rate leads to the reduction of slip velocity between the phases. Therefore, the dispersed phase holdup increases with increase in continuous phase velocity, and consequently, the column becomes unstable at lower dispersed phase velocities. it can be also concluded that at increasing pulsation intensities, the maximum throughput of the column decreases. This phenomenon happens due to a decrease of the drop size with increasing pulsation intensity, which results in an increasing holdup. Additionally, in the present work, two correlations are derived to predict the flooding velocity and holdup at flooding points in the pulsed packed columns. Comparison of experimental data and calculated values for flood velocity and dispersed phase holdup at the flood point shows that these correlations have an excellent agreement between prediction and experiments (average absolute relative error less than 6%)
  9. Keywords:
  10. Emulsion Liquid Membrane ; Flooding ; Plused Packed Column ; Dispersed Phase Holdup ; Dysprosium Separation ; Immobilized Liquid Membrane ; Bulk Liquid Membrane ; Liquid-Liquid Extraction

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