% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@PHDTHESIS{Schupsky:885822,
      author       = {Schupsky, Jan Peter},
      title        = {{C}rystallisation of {O}xidic {G}asifier {S}lags},
      volume       = {514},
      school       = {RWTH Aachen},
      type         = {Dissertation},
      address      = {Jülich},
      publisher    = {Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag},
      reportid     = {FZJ-2020-04113},
      isbn         = {978-3-95806-506-2},
      series       = {Schriften des Forschungszentrums Jülich. Reihe Energie
                      $\&$ Umwelt / Energy $\&$ Environment},
      pages        = {III, 127, XXII S.},
      year         = {2020},
      note         = {RWTH Aachen, Diss., 2020},
      abstract     = {Gasification is a flexible technology that has the
                      potential to support the transition from a fossil fuelled to
                      decarbonised energy supply system. During gasification, an
                      oxidic residue is produced thatis named as slag. Slag flow
                      needs to be constant in a gasifier, but a high viscosity
                      impairs the flow behaviour. The phenomenon of
                      crystallisation has such effect, yet is only barely
                      understood. Viscosity of slag can be modelled and therefore
                      predicted. However, no sufficient model exists to calculate
                      the viscosity of partly crystallised slags. A sufficient
                      data source of crystal morphology data is required to enable
                      the application of an improved viscosity model for partly
                      crystallised slags. In this study, the crystallisation
                      characteristics of four synthetic gasifier slags (ST-D-2,
                      HKT, SOM-1,and HKR) have been investigated. Initially, the
                      synthetic slag systems have been blended from high purity
                      compounds. Their compositions are mostly based on real coal
                      slags that have been investigated in previous studies. The
                      slag systems were analysed on their melting and
                      solidification behaviour and so, the temperature parameters
                      for the following experiments were set. Equilibrium
                      calculations were conducted with FactSage Equilib programme
                      to predict solidus and liquidus temperatures, as well as the
                      crystallised phases. As a first experiment, high temperature
                      viscosimetry was performed on the four slag systems. ST-D-2
                      and HKT slags were identified as high viscous, HKR as a low
                      viscous and SOM-1 as an intermediately viscous slag.
                      Viscosity measurements revealed non-Newtonian behaviour and
                      the presence of crystals in the slag. The evolution of
                      crystallisation was analysed by quenching and CLSM (confocal
                      laser scanning microscopy) experiments. The resulting slag
                      samples were analysed via microscopy, X-ray diffraction and
                      SEM (scanning electron microscopy). ST-D-2, HKT, and SOM-1
                      slag displayed significant growth of anorthite
                      (CaAl$_{2}$Si$_{2}$O$_{8}$)crystals. Several more phases
                      crystallised in these slags, such as cristobalite
                      (SiO$_{2}$), clinopyroxene((Ca,Mg,Fe)(Si,Al)$_{2}$O$_{6}$),
                      and olivine ((Ca,Mg,Fe)$_{2}$SiO$_{4}$). In the HKR slag,
                      melilite (Ca$_{2}$(Al,Mg)(Si,Al)$_{2}$O$_{7}$)was the
                      dominating crystal phase, followed by olivine and spinel
                      ((Mg,Fe)AlO$_{4}$). For the high viscous slags,
                      time-temperature-transformation (TTT) diagrams indicated an
                      incubation time of single hours. SOM-1 slags incubation time
                      varied between double digit minutes to single hours and
                      lastly HKR slag displayed very rapid, partly instant
                      crystallisation. The crystal morphologies of anorthite,
                      spinel, olivine, and melilite could be defined based on the
                      sample analysis of quenching and CLSM experiments. Anorthite
                      was defined as a tetragonal prism with variation in the
                      elongation, spinel formed idiomorphic octahedrons, olivine
                      crystallised aselongated, equiaxed bipyramids and melilite
                      formed large rectangular bipyramids. To gather relevant
                      morphology data, the crystals were measured on their length
                      and width to quantify their presence with respect to the
                      applied temperature. In total, 1022 individual crystals were
                      measured for the quantification. Generally, the crystals
                      tend to grow larger at higher temperatures, which is in
                      agreement with the crystallisation theory. The morphology
                      was compared with crystallisation of real slag samples from
                      PiTER reactor (TU Munich, HotVeGas project). Anorthite and
                      spinel were found in PiTER slag with identical morphologies,
                      as provided for the synthetic slag samples. This accordance
                      is an application-related proof that the investigations on
                      crystal morphologies performed in this study are
                      reproducible and realistically display crystallisation
                      processes in gasifiers. Therfore, they are highly applicable
                      in viscosity models for partly cristallised slags.},
      cin          = {IEK-2},
      cid          = {I:(DE-Juel1)IEK-2-20101013},
      pnm          = {899 - ohne Topic (POF3-899)},
      pid          = {G:(DE-HGF)POF3-899},
      typ          = {PUB:(DE-HGF)3 / PUB:(DE-HGF)11},
      urn          = {urn:nbn:de:0001-2020120102},
      url          = {https://juser.fz-juelich.de/record/885822},
}