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Keywords:

  • radial-flow naphtha reactor;
  • hydrogen production;
  • aromatic boosting;
  • membrane separations;
  • mathematical modeling

Abstract

Naphtha reforming units are of high interest for hydrogen production in refineries. In this regard, the application of membrane concept in radial-flow tubular naphtha reactors for hydrogen production is proposed. Because of the importance of the pressure drop problem in catalytic naphtha reforming units, the radial-flow reactors are proposed. A radial-flow tubular membrane reactor (RF-TMR) with the radial-flow pattern of the naphtha feed and the axial-flow pattern of the sweeping gas is proposed as an alternative configuration for conventional axial-flow tubular reactors (AF-TR). The cross-sectional area of the tubular reactor is divided into some subsections in which walls of the gaps between subsections are coated with the Pd-Ag membrane layer. A dynamic mathematical model considering radial and axial coordinates ((r, z)-coordinates) has been developed to investigate the performance of the new configuration. Results show ∼300 and 11 kg/h increase in aromatic and hydrogen production rates in RF-TMR compared with AF-TR, respectively. Furthermore, smaller catalyst particles with higher efficiency can be used in RF-TMR due to a slight pressure drop. The enhancement in aromatics (octane number) and hydrogen productions owing to applying simultaneously the membrane concept and radial-flow pattern in naphtha reactors motivates the application of RF-TMR in refineries. © 2011 American Institute of Chemical Engineers AIChE J, 2012