Method for operating catalytic reformers

Abstract

A reforming process in which a hydrocarbon feed containing aliphatic hydrocarbons is converted to a hydrocarbon product comprising an increased proportion of aromatics by passage over a reforming catalyst in a sequence of moving bed reactors operating under reforming conditions including moderate hydrogen pressure. The process is applicable when a former fixed moving bed reformer has been converted to moving bed reactor operation with the recycle and other ancillary equipment retained so that moderate pressure (hydrogen partial pressure at least 11 barg) is required, usually with a catalysts such as Pt/Re which tend to exhibit excessive hydrogenolysis activity in moving bed service. The recycle hydrogen stream is split with a portion going to at least one reactor subsequent to the first reactor.

1. A reforming process in which a hydrocarbon naphtha feed containing aliphatic hydrocarbons is converted to a hydrocarbon product comprising an increased proportion of aromatics by passage over a reforming catalyst in a sequence of moving bed reactors operating under reforming conditions including a hydrogen partial pressure of at least 11 barg in which hydrogen is fed to at least one reactor subsequent to the first reactor in addition to the first reactor of the sequence. 
     
     
       2. A process according to  Claim 1  in which the hydrogen fed to the reactors is recycle hydrogen separated from the reforming products. 
     
     
       3. A process according to  Claim 2  in which the sequence of moving bed reactors includes three reactors and the hydrogen is fed to the first reactor and the second reactor of the three-reactor sequence. 
     
     
       4. A process according to  Claim 2  in which the hydrogen separated from the reforming products is heated by heat exchange with the reforming products prior to entering the first reactor. 
     
     
       5. A process according to  Claim 3  in which the hydrogen separated from the reforming products is heated by heat exchange with the reforming products prior to entering the first and the second reactor of the sequence. 
     
     
       6. A process according to  Claim 5  in which the hydrogen separated from the reforming products is split into two streams which are heated separately by heat exchange with the reforming products. 
     
     
       7. A process according to  Claim 1  in which the reforming catalyst is a Pt/Re catalyst. 
     
     
       8. A process according to  Claim 1  which is operated at a pressure of 12 to 30 barg measured at the inlet of the first reactor. 
     
     
       9. A process according to  Claim 8  which is operated at a pressure of 12 to 27 barg measured at the inlet of the first reactor. 
     
     
       10. A process according to  Claim 9  in which the reforming catalyst is a Pt/Re catalyst. 
     
     
       11. A reforming process in which a hydrocarbon naphtha feed in the boiling range of 60° to 200° C. which contains aliphatic hydrocarbons is converted to hydrogen and a hydrocarbon product comprising an increased proportion of aromatics relative to the naphtha feed by passage over a reforming catalyst under reforming conditions including a temperature in the range of 425°-650° C. and a hydrogen partial pressure of at least 11 barg in a sequence of moving bed reforming reactors following which hydrogen is separated from the hydrocarbon reforming product and recycled to the first reactor of the sequence and to at least one reactor in the sequence subsequent to the first reactor. 
     
     
       12. A process according to  Claim 11  in which the sequence of moving bed reactors includes three reactors and the hydrogen is fed only to the first reactor and the second reactor of the three-reactor sequence. 
     
     
       13. A process according to  Claim 12  in which the hydrogen separated from the reforming products is heated by heat exchange with the reforming products prior to entering the first reactor. 
     
     
       14. A process according to  Claim 13  in which the hydrogen separated from the reforming products is heated by heat exchange with the reforming products prior to entering the first and the second reactor of the sequence. 
     
     
       15. A process according to  Claim 14  in which the hydrogen separated from the reforming products is split into two streams which are heated separately by heat exchange with the reforming products. 
     
     
       16. A process according to  Claim 11  in which the reforming catalyst is a Pt/Re catalyst. 
     
     
       17. A process according to  Claim 11  which is operated at a pressure of 12to 30 barg measured at the inlet of the first reactor. 
     
     
       18. A process according to  Claim 17  which is operated at a pressure of 12to 27 barg measured at the inlet of the first reactor. 
     
     
       19. A process according to  Claim 18  in which the reforming catalyst is a Pt/Re catalyst. 
     
     
       20. A reforming process in which a hydrocarbon naphtha feed in the boiling range of 60° to 200° C. which contains aliphatic hydrocarbons is converted to hydrogen and a hydrocarbon product comprising an increased proportion of aromatics relative to the naphtha feed by passage over a reforming catalyst comprising platinum and rhenium on an alumina support under reforming conditions including a temperature in the range of 425°-550° C. and a hydrogen partial pressure of at least 12 barg in a sequence of three moving bed reforming reactors following which hydrogen is separated from the hydrocarbon reforming product and split into two streams, one of which is heated by heat exchange with reforming product effluent from the third reactor of the sequence before being recycled to the first reactor of the sequence with the other stream being separately heated by heat exchange with reforming product effluent from the third reactor of the sequence before being recycled to the second reactor of the sequence.