Garciadiego Ortega, Eduardo;
(2020)
Studies of intensified liquid-liquid extractions in small-channel contactors and their scale-up.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
This thesis presents a series of investigations focused on scaling-up intensified liquid-liquid flow processes from single-channel to commercial-scale. The process investigated consists of liquid-liquid extractions of U(VI) from nitric acid to an organic phase. These extractions are relevant to the safety and sustainability of the nuclear fuel cycle. The intensified contactor consists of a tee-junction feeding to a channel with small internal diameter (1 to 4 mm) operating under segmented flow pattern. Segmented flow contactors intensify liquid-liquid extractions in uranium recovery processes because they provide intense mixing, short diffusion distances, and large interfacial area at low energy input. Using high-speed imaging, UV-Vis spectroscopy, pressure gradient measurements, and dimensional analysis, the operation and design trade-offs are quantitatively identified with focus on scale-up. A finite-element model is used to corroborate the experimental mass transfer results. The scale-up is achieved via numbering-up, which increases the number of process units instead of making one larger unit. Economic parallelisation requires effective flow distribution. Multiphase flow distribution has been a persistent problem in the path towards commercialisation. This problem is addressed by modelling a double manifold with a resistance network model and a novel method to quantify maldistribution, derived from multivariate statistical analysis. The relationships between the hydraulic resistances with maldistribution, pumping power, and the number of channels are quantified. Finally, the single-channel results and the flow distributor model are used to design, build, and test a modular multichannel segmented flow contactor prototype. The design and commissioning steps are described along with the experimental maldistribution results, including flow distribution and mass transfer results. The multichannel contactor can be operated with different number of channels at any time, thus changing a long-standing paradigm in reactor design. This promises to accelerate process development by facilitating the transition from bench to pilot and commercial scales.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Studies of intensified liquid-liquid extractions in small-channel contactors and their scale-up |
| Event: | UCL (University College London) |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2020. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| Keywords: | Multiphase flow, Two-phase flow, Segmented flow, Taylor flow, Microreactor, Liquid-liquid extraction, Solvent extraction, Process intensification, Scale-up, Scale-out, Numbering-up, PUREX, Spent nuclear fuel, Flow distribution, Resistance network, Interfacial mass transfer, pressure drop |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Chemical Engineering |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10095887 |
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