Process for hydroprocessing a hydrocarbon stream
A process and apparatus provides alternative hydrotreating reactor trains for hydrotreating a hydrocarbon stream. One hydrotreating reactor train is smaller than the other and the smaller train comes on stream to allow replacement or regeneration of catalyst in the larger train. A sulfide system also sulfides the catalyst volume in the reactor train that is off stream to prepare it for renewed hydroprocessing of feed when back on stream. The process and apparatus can be used to keep hydroprocessing reactors on stream to continuously provide feed to an FCC unit which has a longer period before shut down.
1. A process for hydroprocessing a hydrocarbon stream comprising:
feeding said hydrocarbon stream and a hydrogen stream to a first volume of hydroprocessing catalyst to hydroprocess said hydrocarbon stream in the presence of said hydrogen stream to provide a first hydroprocessed stream; terminating feed of said hydrocarbon stream to said first volume of catalyst; and feeding said hydrocarbon stream and said hydrogen stream to a second volume of hydroprocessing catalyst, said second volume being smaller than said first volume of catalyst to hydroprocess said hydrocarbon stream in the presence of said hydrogen stream to provide a second hydroprocessed stream, wherein said first hydroprocessed stream is fed to a fluid catalytic cracking reactor before said termination step and feeding said second hydroprocessed hydrocarbon stream to said fluid catalytic cracking reactor after said termination step.
2. The process of claim 1 wherein said first volume of catalyst is aggregately provided in at least two separate reactors and said second volume of catalyst is provided in a single reactor.
3. The process of claim 1 wherein said first feeding step to said first volume of catalyst endures for a longer time than said second feeding step to said second volume of catalyst.
4. The process of claim 1 further comprising operating the fluid catalytic cracking unit for a continuous cracking period without a shut down.
5. The process of claim 4 further comprising feeding said hydrocarbon stream and said hydrogen stream to said first volume of hydroprocessing catalyst for a first hydroprocessing period up to said termination step that is shorter than said continuous cracking period and said termination step is during said cracking period.
6. The process of claim 1 further comprising feeding a sulfide oil comprising a sulfiding agent to said second volume of catalyst before said termination step and feeding said sulfide oil comprising said sulfiding agent to said first volume of catalyst after said termination step.
7. The process of claim 1 further comprising separating said first hydroprocessed stream in a separator before said termination step and separating said second hydroprocessed hydrocarbon stream in said separator after said termination step.
8. The process of claim 7 further comprising stripping a liquid hydrocarbon stream from said separation step and passing said stripped liquid hydrocarbon stream to a fluid catalytic cracking reactor.
9. The process of claim 1 further comprising terminating feed of said hydrocarbon stream to said second volume of catalyst and repeating the steps of claim 1 .
10. The process of claim 1 wherein said first volume of catalyst is provided in more reactor vessels than said second volume of catalyst.
11. The process of claim 1 wherein said second volume of catalyst and said first volume of catalyst have the same ratio of large pores to small pores on the hydroprocessing catalyst.