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@PHDTHESIS{Faulde:849069,
      author       = {Faulde, Miriam Anna Barbara},
      othercontributors = {Jupke, Andreas and Wöll, Dominik},
      title        = {{I}ntensification of liquid-liquid extraction columns by
                      microgels},
      school       = {Rheinisch-Westfälische Technische Hochschule Aachen},
      type         = {Dissertation},
      address      = {Aachen},
      publisher    = {RWTH Aachen University},
      reportid     = {RWTH-2022-06544},
      pages        = {1 Online-Ressource : Illustrationen},
      year         = {2022},
      note         = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
                      University; Dissertation, Rheinisch-Westfälische Technische
                      Hochschule Aachen, 2022},
      abstract     = {For extraction columns the drop size and drop size
                      distribution are crucial for process performance. Small
                      drops promote mass transfer by large interfacial area while
                      larger drops withstand higher counter current flow rates.
                      The tendency of the drop to coalesce requires constant
                      energy input to break the drops. Hence, the interplay
                      between coalescence and breakage regulates the drop size and
                      often leads to broad size distribution. A new approach to
                      tackle this drop size dilemma is the application of
                      microgels. The crosslinked polymers can stabilize and
                      destabilize liquid systems on demand by a very sensitive
                      temperature trigger. With the combination of interfacial
                      activity and switchability, microgels enable new options for
                      processes with defined monodisperse drop size. For the
                      successful introduction of microgels to extraction
                      processes, the effect of the interfacial microgel layer on
                      the processes relevant phenomena needs to be understood.
                      Thus, the impact of microgels on fluid dynamics, mass
                      transfer and coalescence is investigated in this work. To
                      identify advantageous microgel properties four different
                      microgels are utilized, differing in size and crosslinking.
                      Furthermore, the propagation of effects is evaluated across
                      scales from liquid-liquid interface to technical lab scale,
                      with focus on single drops as smallest self contained unit
                      of the process.The results from single drop experiments
                      indicate that the predominant effect of microgels is the
                      reduction of interfacial mobility. The effect of the
                      microgels on the drops´ fluid dynamics increases with
                      increasing spreading and interpenetration of the microgels
                      at the interface. This also affects the other investigated
                      phenomena. A reduced mass transfer was observed at single
                      drops, while no additional mass transfer resistance of the
                      microgel layer itself was measured for small molecules at a
                      flat interface. Thus the reduced interfacial mobility must
                      cause a reduced decay of the concentration gradient inside
                      the drop. Regarding coalescence the probability for two
                      colliding drops is significantly reduced by microgels below
                      their switching temperature. This could also be accounted to
                      reduced interfacial mobility since it affects the film
                      drainage and thus required contact time for coalescence.
                      Moreover, phase separation by temperature shift was
                      successfully demonstrated in a continuous operating
                      prototype in technical lab scale.Further, performance
                      evaluation by process simulations with monodisperse microgel
                      covered drops show a capacity increase to higher loads at
                      equal separation performance. And at low loads monodisperse
                      drops increase the separation performance and enable
                      operation close to entrainment limit. This work demonstrates
                      the applicability of microgels in extraction columns and
                      also identifies the interfacial spreading and mobility as
                      crucial properties for this scope of application.},
      cin          = {416310},
      ddc          = {620},
      cid          = {$I:(DE-82)416310_20151215$},
      pnm          = {SFB 985 C05 - Mikrogele für die Kombination einer
                      enzymatischen Reaktion mit einer in situ Extraktion in
                      Flüssig-flüssig-Systemen (C05) (317485694) / DFG project
                      191948804 - SFB 985: Funktionelle Mikrogele und
                      Mikrogelsysteme (191948804)},
      pid          = {G:(GEPRIS)317485694 / G:(GEPRIS)191948804},
      typ          = {PUB:(DE-HGF)11},
      doi          = {10.18154/RWTH-2022-06544},
      url          = {https://publications.rwth-aachen.de/record/849069},
}