Auto-Ignition considerations?
Auto-Ignition considerations?
(OP)
I have a relief valve on a reactor that we are considering a fire scenario, 85% filled with heptane. My concern is that the normal auto-ignition temperature of heptane is ~399F-433F and at the set pressure of 50 psig, the corresponding vapor temperature is 320F. I have read that a species' auto-ignition temp. lowers with increasing temperature so I am wondering if at 50 psig the auto-ignition temp. would be at or near the corresponding temperature. Thoughts?





RE: Auto-Ignition considerations?
Good luck,
Latexman
RE: Auto-Ignition considerations?
RE: Auto-Ignition considerations?
RE: Auto-Ignition considerations?
To determine if you can safely discharge this to atmosphere, you would need to determine how the vapors would become dispersed upon release. If the velocity is hight enough there could be jet-mixing, which would better disperse the vapor and reduce (but not eliminate) the possibility for ignition. API 521 gives good guidance on this and also tells you how to calculate whether jet mixing would occur.
RE: Auto-Ignition considerations?
RE: Auto-Ignition considerations?
HOWEVER, the auto ignition would be of a concern with other scenerios, non fire thermal, valve failure, tube rupture ect...
Back to 521 or the need for a vent line/header.