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Keywords:

  • sorption enhanced reaction;
  • multiscale design;
  • multifunctional catalyst;
  • porous diffusion;
  • natural gas reforming;
  • hydrogen

Abstract

A multiscale simulation and characterization framework has been developed for sorption enhanced reaction processes with heterogeneous multifunctional catalysts with sorption properties. Particles with in situ catalytic and sorption functionalities have obvious advantages in achieving high-purity and productivity. These processes are strongly limited by diffusion inside particle. In order to tackle this problem a more detailed characterization at particle level is essential, which is the main objective here. A unified framework has been developed that integrates continuum model at bulk scale with the diffusion-reaction-sorption model at particle porous scale in a fixed-bed reactor. At bulk scale the objectives of purity and productivity are sensitive to various design and operating variables, such as wall temperature, bed voidage and feed compositions, etc. Two important particle level characteristics are also identified: distribution of catalyst and sorbent inside particles, and the ratio of pore radius to tortuosity. It has been demonstrated that considering detailed diffusivity model at porous level offers better insights into catalyst design and process intensification. Natural gas reforming reaction with sorption producing pure hydrogen for fuel cell and combustion applications has been used as a case study to establish the effectiveness of the methodology. © 2008 American Institute of Chemical Engineers AIChE J, 2008