In order to exists salts must have water condensation and once formed the salt, the same can travel in the tower, to a temperature of 230ºF could be condensing water in the tower, as a rule FW designed so that the tower operates to a temperature in the top between 240 to 260ºF (25ºF over the dew point), all depend of the water content in the top current (molar fraction of the water)
This unit handles enough water, which comes from the steam or water for speed in the furnace, the steam purge to the valves and instruments, the steam going to the LCGO or HCGO stripper (if it has them)
Maybe you can make a water balance and calculates this temperature in the top (dew point), to be sure that you dont have below the dew point during the different step of the operation (switching, stripping to the fractionator….)
Im sorry for my english, best regards
