We have to repair a process colummn in our refinery. One of the activities is PWHT. In order to define technical specifications, could anyone tell me a practice and fast procedure to carry out in site PWHT in the column (i.e. Any procedure to do PWHT in site using thermal resitances covered with blanketing).

When I tell "in site" I refere we goin to carry out the column to a maintenance area into our refinery.

Regards,

what is your material and thickness involved, and design code?
you can look into UCS56, if it is designed per ASME VIII div1. else check the MDR of that vessel, you could get the original data provided during fabrication of this vessel

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Raghuram