A MODEL OF NAPHTHA REFORMING IN A RADIAL FLOW MOVING BED REACTOR

• Main Author: MOHAMED ZI, NURUL SHAHIDA
• Format: Thesis
• Language: English; English; English; English; English; English
• Published: 2011
• Online Access: http://utpedia.utp.edu.my/3056/1/CHAPTER_1.pdf; http://utpedia.utp.edu.my/3056/2/CHAPTER_2.pdf; http://utpedia.utp.edu.my/3056/3/CHAPTER_3.pdf; http://utpedia.utp.edu.my/3056/4/CHAPTER_4.pdf; http://utpedia.utp.edu.my/3056/5/CHAPTER_5.pdf; http://utpedia.utp.edu.my/3056/6/CHAPTER_6.pdf; http://utpedia.utp.edu.my/3056/

Catalytic reforming of naphtha is widely practiced in the petroleum industry to produce aromatics. Latest technology utilizes novel radial flow moving bed reactors for the reforming process as well as regeneration of the slowly decaying catalyst. Catalyst circulation between the reformer and regeneration units makes continuous operation of reformer-regenerator unit possible. In spite of their extensive use, very little is known about the performance of radial flow moving bed reformer unit. The radial flow moving bed reformer consists of four reactor units (R1, R2, R3 and R4) stacked one on top of the other with catalyst flowing downward by gravity as a moving bed. In each reactor unit the catalyst flows downwards through an annulus with reactants flowing radially inwards through the moving bed of the catalyst. The reactants flow through the four units in series and are preheated before entering each unit. Temperature of the product stream exiting each unit is lower as the reactor is adiabatic and reactions are net endothermic. A one dimensional compartment in series multiphase catalytic reactor model considering the catalyst deactivation is developed to explain the performance of a radial flow moving bed reformer. The model estimates on the trends of temperature and composition profiles are in reasonable agreement with the limited industrial information available. The model is used to simulate various scenarios to identify possible strategies to improve productivity of aromatics. Feeding the fresh feed in R1 and R3 and recovers the products at R2 and R4 is much better than feeding the fresh feed in R1 and recovers the products in R4. Simple models to account for pinning and rate of breakage of catalyst particles are proposed.