Explotions at sulphur pit
Explotions at sulphur pit
(OP)
Hi,
We have a sulphur pit that we use for degassing (take out SH2 and polisulphurs), removing sulphur through centrifugal vertical pumps. It is made, nearly all, of carbon steel (sleeves, thermowelds and pumps), but also we have stainless steel in different parts (downs to heaters, and catalyst inyections).
It has an forced air circulation, that an ejector makes, and sucks the mix atmosphere to a furnace (that also works with vacuum)
Well, we are having fires inside (even explotions) the pit, at the time when we use sweep air. We detected high levels of SO2 before accident, but no high temperatures. Does anybody knows any reason in order that this phenomenon produces? SFe formation is possible, even though we are using continuesly air?. What about sulphur dust? Dead zones in our pit? Any similar expierence in your instalations?
Thanks a lot
We have a sulphur pit that we use for degassing (take out SH2 and polisulphurs), removing sulphur through centrifugal vertical pumps. It is made, nearly all, of carbon steel (sleeves, thermowelds and pumps), but also we have stainless steel in different parts (downs to heaters, and catalyst inyections).
It has an forced air circulation, that an ejector makes, and sucks the mix atmosphere to a furnace (that also works with vacuum)
Well, we are having fires inside (even explotions) the pit, at the time when we use sweep air. We detected high levels of SO2 before accident, but no high temperatures. Does anybody knows any reason in order that this phenomenon produces? SFe formation is possible, even though we are using continuesly air?. What about sulphur dust? Dead zones in our pit? Any similar expierence in your instalations?
Thanks a lot





RE: Explotions at sulphur pit
RE: Explotions at sulphur pit
Our sulphur pit is under vacuum and uncondensed gases go to incinerator for burning. We use snuffing steam to extinguish sulphur pit fires.
Luis
RE: Explotions at sulphur pit
RE: Explotions at sulphur pit
Though I like your earlier suggestion to set your steam pressure at 50 psig, I really don't think having 70# steam instead of 50# steam would create the problem you describe. I am aware of the unusual property that sulfur has to exhibit higher viscosity as temperature is increased, but don't accept this as an explanation. It would take substantially higher steam pressures to get near a problem area, in my opinion. In fact, using 35# steam would be more likely to lead to problems of not getting enough heat into your molten sulfur.
I welcome your return comments,
Doug
RE: Explotions at sulphur pit
Under normal circustances in a pipe or vessel, I agree. But in the pump we have bushing that are surrouding a sleeve turning at 3600 rpm. If the temperature of the sulfur is incresed even a relatively small amount, it becomes more viscous. At higher viscosity, there is more heat generated from shear in the bushings. This heats the sulfur up even more. At some point it becomes a runaway process that results in tripping off the motor or seizing up the pump. We had this problem even with correct jacketing temperatures. We found that the bushing clearances were too tight. But increaseing the bushing clearance from 0.014" to 0.020" the problem went away. No more pump trips and no more pit fires. I do believe that 70# steam is enough the initiate the same process.
Thanks for your reply.
Johnny
RE: Explotions at sulphur pit
Even so, we have checked steam pressure in all our jackets(that is 50#), also bushings and motor amps. Our analyser works propperly, and so our gas thermocouples.
Just aligning air and taking off snuffing steam it starts to burn (our meassure gadgets note an increase of TÂȘ and of SO2)
I am absolutly convinced that fire is provocated by pyroforic elements we have inside. Do yo think Carbon Steel elements could cause this? Anyone have seen pits (where sulphur drops from the unit and where you degass) made of this material and whitout damages?
Thank you for your answers.
Best regards,