Generally demister pads should be inspected at every shutdown for checking the healthiness. Sometimes demister pads are damaged beyond repair which need for a replacement.
Choked demister pads can normally be cleaned unless its for Sulfur Condensers. Demister pads at the outlet of S condensers are either choked with Solid S (hard to remove without damaging the pad) or damaged during hot sweeping (excess air burns sulfur present in the pads).
