Reason for the ignition of gas at the outlet of the ammonium sulfate saturator
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The ammonium sulfate saturator was taken out of service due to corrosion and leakage in the gas outlet pipeline; the gas outlet valve of the saturator was closed. The inlet valve of the gas preheater was closed halfway because of a problem with its handwheel, and both the gas preheater and the saturator were under positive pressure. At around 3:20 p.m., the fire broke out without any welding or maintenance work being carried out, with no lighting cables in the vicinity and no thunderstorms present. What other could be the causes of the fire? Has anyone encountered this problem?
The temperature of the gas after the saturator will not exceed 60 degrees – is that normal? Gas pipelines require static grounding, but we don’t have that; only the pipe racks are grounded. How can static electricity be detected? Could it cause the gas to catch fire?
I’ve encountered this issue before: you didn’t clean the saturator and preheater properly. In particular, sulfur and iron in the preheater reacted to form certain substances that can form naturally. So once you stop operating the saturator for maintenance, quickly clean the preheater and saturator using steam, ensuring that the cleaning process lasts as long as possible. After cleaning, open the manholes to check
Yes, during maintenance, especially after the inlet pipes of the preheater were removed, air entering would cause combustion. The key point is that this time the pipes were not removed; both the preheater and the saturator were under positive pressure with gas flowing through them, yet a fire still occurred.
Is it on the outside or inside? If there’s a fire inside, then air must have gotten in; and air doesn’t enter on its own. If it’s on the outside, it’s due to an external source of fire
There was a gas leak; it must have been ignited by an open flame – it’s not necessarily due to work-related welding
The original poster didn’t explain clearly whether it was the gas that caught fire or the substances inside the pipes. If it was the substances in the pipes that ignited, it’s very likely that ferrous sulfide spontaneously combusted upon contact with oxygen
It should be elemental sulfur that results from the decomposition of sulfides attached to the pipes over a long period of time. Due to the properties of sulfur, sulfur vapor can sublimate and ignite spontaneously at certain temperatures.