Nozzles are located to suit process operation and maintenance requirements and to facilitate an economic and orderly interconnection of piping between the reactor and related equipment.
The following information is required to locate and elevate reactor nozzles.
- Process vessel sketch.
- Instrument vessel sketch.
- Piping line list
- Nozzle summary
- Plant layout specification.
- Insulation requirements.
The process inlet is located at the top head of the reactor along with
maintenance access, which is used for catalyst loading.
On small diameter reactors, whose space is limited, the inlet nozzle can be integral with maintenance access.
Following figure shows a typical top head arrangements.
The process outlet and catalyst unloading nozzles are located on the bottom head of the reactor.
If the reactor is skirt supported, the outlet is arranged like a tower bottoms outlet.
If supported by lugs or by a ring girder, the nozzle is vertical on the centreline of the vessel that terminates at the nozzle flange.
The catalyst unloading nozzle is angled from the bottom head to clear the skirt and is positioned between the piers on lug supported reactors and below the table top on ring girder supported reactors.
Following figure shows a typical bottom head arrangements.
In certain cases, especially with stacked reactors, catalyst unloading nozzles are located in the side of the reactor, as shown below.
Temperature instruments are usually required at reactors; they are used to measure the temperature at different levels of the catalyst bed.
These instruments can be individual nozzles located at various levels on the shell of the reactor or to minimize multiple connections, immersed in a well from the top of the reactor, either on an individual nozzle or through the maintenance access.
Instrument requirements for reactor are usually highlighted on a vessel instrument sketch that is furnished by the instrument engineer.
Following drawing shows side mounted temperature instruments.
Following drawing shows a top head vertical arrangement.
Sample probe connections, which are sometimes specified, are usually located on the side shell of the vessel as shown below.