Abstract

In petroleum refineries, naphtha reforming units produce reformate streams and as a by-product, hydrogen (H2). Naphtha reforming units traditionally deployed are designed as packed bed reactors (PBR). However, they are restrained by a high-pressure drop, diffusion limitations in the catalyst, and radial and axial gradients of temperature and concentration. A new design using the fluidized bed reactor (FBR) surpasses the issues of the PBR, whereby the incorporation of the membrane can improve the yield of products by selectively removing hydrogen from the reaction side. In this work, a sequential modular simulation (SMS) approach is adopted to simulate the hydrodynamics of a fluidized bed membrane reactor (FBMR) for catalytic reforming of naphtha in Aspen Plus. The reformer reactor is divided into five sections of plug flow reactors and a continuous stirrer tank reactor with the membrane module to simulate the overall FBMR. Similarly, a fluidized bed reactor (FBR), without membrane permeation phenomenon, is also modelled in the Aspen Plus environment for a comparative study with FBMR. In FBMR, the continuous elimination of permeated hydrogen enhanced the production of aromatics compound in the reformate stream. Moreover, the exergy and economic analyses were carried out for both FBR and FBMR.

Highlights

  • Catalytic reforming of naphtha converts low-octane straight-run naphtha, from crudeoil distillation towers, into high-octane reformates

  • The Aspen Plus software has been used intensively for a comparative study of fluidized bed membrane reactor (FBMR) and fluidized bed reactor (FBR) models, but the exergy analysis was not included in the comparison [21,22,23]

  • The Aspen Plus based process flow diagram of FBMR and FBR is given in Figures 6 and 7, respectively

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Summary

Introduction

Catalytic reforming of naphtha converts low-octane straight-run naphtha, from crudeoil distillation towers, into high-octane reformates. A fluidized catalyst bed reactor is included with Pd membrane-based walls in the naphtha reforming process. This reactor configuration enables the selective in-situ removal of hydrogen from product gases, which increases the production of aromatics. Khosravanipour and Rahimpour [15] as well as Rahimpour et al [11] presented the concept of membrane assisted naphtha reformer and studied the effects of in-situ hydrogen separation in a packed bed reactor and fluidized bed reactor for naphtha reforming. The Aspen Plus software has been used intensively for a comparative study of FBMR and FBR models, but the exergy analysis was not included in the comparison [21,22,23].

Process Description
Membrane Reactor and its Modelling Method
Preliminary Assumptions
Exergy Analysis
Economic Analysis
Results and Discussion
Influence of Reactor Temperature
Influence of Shell-Side Pressure
Influence of Membrane Thickness
Aromatics and Hydrogen Yields
Thermoeconomic Analysis
Conclusions
Full Text
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