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Fluidized bed hydrodynamic modelling of CO2 in syngas: Distorted RTD curves due to adsorption on FCC
  • Ariane Berard,
  • Bruno Blais,
  • Gregory Patience
Ariane Berard
Polytechnique Montreal
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Bruno Blais
Polytechnique Montreal
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Gregory Patience
Polytechnique Montreal
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Abstract

The hydrodynamics of gas-phase fluidized beds is non-ideal due to high velocity. Micro-fluidized beds have distinct flow patterns because of the wall and the diameter constrains bubble velocity. We measured the gas phase RTD in a 8 mm ID quartz tube loaded with fluid catalytic cracking catalyst (FCC). We devised a feed manifold to introduce a 4-component tracer gas as a bolus pulse. The FCC separated the gases based on diffusivity like chromatography. At ambient temperature, the trailing edge of CO, CH4, and CO2 have extended tails and an axial dispersion model accounts only for 92 % of the variance. We developed a model to characterize the tailing that includes diffusion from the bulk gas to the FCC pores and adsorption-desorption of the gas on the catalyst. This model accounted for 98.6 % of the variance in the RTD. At 300°C the tailing disappeared consistent with expectations in chromatography.