Currently Im working for Spare Reactor ( DP 44 kg/cm2@ 400C / Regeneration DP: 12 kg@ 530C) , the existing Reactor doesn't have HOT BOX at skirt , Just want to know the following ;
1) Is it needed in this item
2) How this hotbox works to reduce thermal gradient
3) Is this required by Code
4) What is the standard configuration of this Hot Box, and how it is installed at skirt.

Thanks !