Sulphur ignition temperature

[RogerH]

I have been searching (in vain) for a correlation between oxygen content and ignition temperature for sulphur. In particular, for sulphur condensed in the reactor (on and in the catalyst) of a Claus reactor.
If a run-away take place one can extinguish the "fire" with nitrogen or steam (acc. to design). The nitrogen at this site used, can contain up to 0.4 mole% oxygen.In other places I worked we have used cryogenic nitrogen, so this have never been an issue.
Oxygen can and will react with the sulphur but the main question is at which temperature does this take place? Is there a risk at "run-away" conditions (i.e. at upper operating temperature in the 1st reactor) that we can support a combustion with oxygen containing nitrogen or not?
One can easliy find ignition point for sulphur with normal air but I haven't sofar been able to see a e.g curve/table for the relationship between oxygen content and ignition temperature for sulphur.
If anybody "out there" do have any information on the subject, I would appreciate some enlightment on the issue.
Thanks

 

[ash9144]

Sulfur burning furnaces for acid production normally run 05-1.0% normal oxygen outlet concentration. So I'd say you could support some combustion at that low a concentration.