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@PHDTHESIS{Mielke:894589,
      author       = {Mielke, Konrad},
      title        = {{V}erhalten und {K}ontrolle von {S}chlacken des
                      bioliq®-{V}ergasers},
      volume       = {548},
      school       = {RWTH Aachen},
      type         = {Dissertation},
      address      = {Jülich},
      publisher    = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
      reportid     = {FZJ-2021-03296},
      isbn         = {978-3-95806-566-6},
      series       = {Schriften des Forschungszentrums Jülich. Reihe Energie
                      $\&$ Umwelt / Energy $\&$ Environment},
      pages        = {162, XXXV S.},
      year         = {2021},
      note         = {RWTH Aachen, Diss., 2021},
      abstract     = {Pressurized entrained-flow gasification of biogenic
                      resources is a sustainable and CO$_{2}$-neutral process to
                      produce biofuels and further carbonaceous products. The
                      bioliq®-process integrates the gasification in a process
                      chain to convert straw and wood residuals into high-quality
                      biofuels. The feedstock is initially converted via fast
                      pyrolysis into a slurry consisting of a tar rich, liquid
                      phase and a char, which is called BioSyncrude®. Afterwards,
                      the bioslurry is converted into an almost tar-free, low
                      methane containing syngas in a pressurized entrained flow
                      gasifier at temperatures above 1200 °C. The syngas is
                      finally used as basic reactant for the production of
                      biofuels. Due to the high temperatures in the entrained-flow
                      gasification the ash from the char melts, flows down the
                      inner wall of the gasifier and is thus continuously removed.
                      Furthermore, the formed slag layer protects the reactor wall
                      against corrosion. Therefore, the characterization of the
                      flow behaviour and the adjustment of the optimal viscosity
                      range by influencing the slurry composition are the main
                      objectives in this thesis. One possibility is to determine
                      the viscosity of the slag from the outflow of the gasifier
                      and deduce the viscosity at the inner reactor wall. The
                      measured and the modelled viscosity values are compared and
                      thus, the viscosity model is evaluated. A second possibility
                      is to simulate the chemical composition of the slag at the
                      inner reactor wall. A thermochemical model uses the
                      composition of the slurry to calculate this slag composition
                      according to gasifier conditions. The focus is on the
                      release of Na and K due to the gasifier conditions before
                      the slag is formed. The modelled viscosities are compared
                      with experimental values to fit and evaluate the model
                      parameters. The advantage of this method is to predict the
                      flow behaviour at the inner reactor wall, which can be
                      preventively adjusted by fluxing. For the economic operation
                      of the gasifier, low viscous slags are preferred to reduce
                      also the operation temperature and minimize the heat loss.
                      Na- and K-rich additives are suitable fluxes, at which the
                      viscosity is more reduced by Na, because it is less volatile
                      at gasifier conditions. Hence, a higher amount of Na is
                      incorporated in the slag network. However, adding too much
                      Na will cause corrosion of the reactor wall and also
                      significant amount of Na in the quench water. The models
                      developed in this work allow for prediction the flow
                      behaviour of the slags at the inner reactor wall.
                      Furthermore, the potential influence of flux can be
                      simulated and the complex reaction behaviour of the ash
                      components can be described. Thus, the relation between the
                      chemical slag composition and its viscosity can be shown in
                      this thesis.},
      cin          = {IEK-2},
      cid          = {I:(DE-Juel1)IEK-2-20101013},
      pnm          = {899 - ohne Topic (POF4-899)},
      pid          = {G:(DE-HGF)POF4-899},
      typ          = {PUB:(DE-HGF)3 / PUB:(DE-HGF)11},
      urn          = {urn:nbn:de:0001-2021100116},
      url          = {https://juser.fz-juelich.de/record/894589},
}