Known and potential causes of sulfur pit fires

[SREisme]

We have an ongoing problem with pit fires (as determined by rapid increase of SO2 in the incinerator stack analyzer) in our SRU sulfur pits and have had this problem since increasing the pump speed from 1800 to 3600rpm to produce enough head to supply a new out of pit degassing system. We know that pump problems, ie hot bearings, lack of lubricating sulfur, mechanical damage, etc, can cause a pit fire. We also know that a pit fire can cause damage to the pumps, both the online and spare pump. What we don't know, is all the other potential sources of a pit fire and what other refineries/ sulfur pit users have experienced. I see there are some threads on iron sulfides as potential causes which makes sense. Has anyone experienced or proven static discharge to be a cause of fires and done anything to eliminate it? Has the falling sulfur from the uppermost intermediate bushing created enough static charge to generate a spark? Does anybody do a "sulfur wash" of their pit to reduce the amount of sulfur fuzz that builds up on the walls and ceiling? Has anyone else experienced similar problems with a pump speed change? Has anyone gone to a nitrogen purged pit to reduce the oxygen content in the vapor space? Does anyone else have problems with"sulfur-crete" plugging the clearances of their pumps? As usual, I have more questions than answers and would greatly appreciate any advice or experience any other users are willing to share. Thanks!

 

[QMax1]

SREisme,

I would suggest you contact someone like Sulphur Experts or Aberta Sulphur Research for a comprehensive view of these problems.

I can confirm that iron oxides can cause creation of pyrophorics which can lead to sulfur fires. The iron oxides are created when sulfur freezes on a steel surface and traps moisture behind it. This is very common.

Good luck,
QMax1