h1

% 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{Alsayegh:728648,
      author       = {Alsayegh, Sari},
      othercontributors = {Weßling, Matthias and Favre, Eric},
      title        = {{H}ydrogen recovery and utilization from water splitting
                      processes},
      school       = {RWTH Aachen University},
      type         = {Dissertation},
      address      = {Aachen},
      reportid     = {RWTH-2018-225811},
      pages        = {1 Online-Ressource (v, i-ii, 124 Seiten) : Illustrationen},
      year         = {2018},
      note         = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen
                      University; Dissertation, RWTH Aachen University, 2018},
      abstract     = {Renewable energy sources must be adopted in order to
                      satisfy the increase in global energy demand all the while
                      minimizing the carbon footprint. One obvious energy source
                      is solar. Aside from traditional electricity generation
                      technologies, solar energy can be utilized to produce H2 (as
                      an energy carrier) via photocatalytic water splitting. In a
                      typical process, both H2 and O2 are produced in the same
                      reactor environment, thereby creating a potentially
                      hazardous scenario. This obstacle can be avoided by
                      utilizing flammability suppressants to recover the product
                      outside the flammability regime. The scope of this thesis is
                      to identify membrane-based processes to recover and utilize
                      H2 generated from photocatalytic water splitting while
                      maintaining safety and flammability constraints throughout
                      the separation process. Two flammability suppressants were
                      investigated, namely: N2 and CO2. Detailed information about
                      H2 flammability in these two diluents and the impact of the
                      operating conditions were described in order to identify the
                      parametric range that ensures a safe separation process. To
                      be more genuine in designing the membrane-based process, an
                      optimization study for the whole process economic was
                      implemented using commercially available membrane materials.
                      These membrane units were incorporated in different process
                      layouts to achieve high purity and recovery values while
                      applying flammability constraints in all pertinent streams.
                      The results for both suppressants revealed the advantage of
                      CO2 over N2 as a suppressant, where the H2 product was
                      recovered at a higher purity with lower specific cost and O2
                      concentration. However, both diluent systems revealed
                      imposing recovery costs due to the low H2 concentration in
                      the feed. Further studies were conducted to show the impact
                      of varying feed compositions, high performance polymeric
                      membrane materials (not commercialized), and alternative
                      membrane configurations (hollow fiber / spiral wound) on the
                      process economics. As a conceptual culmination of the
                      initial process design work, a renewable methanol production
                      route was proposed to integrate technologies into a complete
                      petrochemical facility. Through integration, the aim was to
                      improve the overall process economics through the production
                      of a more value-added product. This approach utilized H2
                      from photocatalytic water splitting and captured CO2 (e.g.
                      flue gas). Contrary to the previous approach, the
                      membrane-based separation process was optimized to produce a
                      3:1 H2 and CO2 mixture. This binary mixture was used as the
                      feedstock for a conceptual direct CO2 hydrogenation methanol
                      synthesis plant. Based on a detailed economic analysis, the
                      break-even value of the methanol produced using this
                      approach is higher than the current market of methanol.
                      However, it is very comparable to other renewable methanol
                      routes proposed in the literature. Sensitivity analysis was
                      carried out on different economic and energy parameters to
                      show their impact on both economic and energy efficiencies
                      of the proposed process. The sensitivity analysis revealed
                      the strong influence of CO2 market price on the process
                      economics over other considered parameters. The design
                      approach and the optimization models developed in this study
                      are not limited to H2 recovery from photocatalytic water
                      splitting. Other gas separation applications, that involve
                      flammability constraints, can be easily implemented. Hence,
                      these models provide a strong tool for similar future
                      works.},
      cin          = {416110},
      ddc          = {620},
      cid          = {$I:(DE-82)416110_20140620$},
      typ          = {PUB:(DE-HGF)11},
      doi          = {10.18154/RWTH-2018-225811},
      url          = {https://publications.rwth-aachen.de/record/728648},
}