mjpetrag
Mechanical
- Oct 16, 2007
- 224
Currently I am in the process of determining whether or not our current LEL detection system is necessary from a process safety and regulatory standpoint (located in US)
The way this system is set up is several vacuum distillation column vents, on the vapor outlets of the jet condensers, are tied together and routed to a knockout pot where several other vapor streams from other processes combined. The outlet of this knockout pot is sent to a catalytic oxidizer, which Is equipped with redundant LEL probes that shut down the unit and vent the upstream flows to atmosphere.
On the distillation column vent system, upstream of the knockout pot, are another set of LEL probes that upon high LEL detected, open a vent to atmosphere and close the valve from the distillation column vents to the KO pot. There is also dilution air that bleeds into the system between the vent to atm/flow to KO pot control valves and LEL probes for dilution air.
The question I have is - are these LEL probes necessary if I have probes at the catalytic oxidizer? The only thing I can think is that there is a potentially explosive mixture in the piping from the distillation column vents and knockout pot, however there would still need to be an ignition source.
We cannot find any documentation saying why these were installed so I am looking for a regulation/best practice in this instance
-Mike
The way this system is set up is several vacuum distillation column vents, on the vapor outlets of the jet condensers, are tied together and routed to a knockout pot where several other vapor streams from other processes combined. The outlet of this knockout pot is sent to a catalytic oxidizer, which Is equipped with redundant LEL probes that shut down the unit and vent the upstream flows to atmosphere.
On the distillation column vent system, upstream of the knockout pot, are another set of LEL probes that upon high LEL detected, open a vent to atmosphere and close the valve from the distillation column vents to the KO pot. There is also dilution air that bleeds into the system between the vent to atm/flow to KO pot control valves and LEL probes for dilution air.
The question I have is - are these LEL probes necessary if I have probes at the catalytic oxidizer? The only thing I can think is that there is a potentially explosive mixture in the piping from the distillation column vents and knockout pot, however there would still need to be an ignition source.
We cannot find any documentation saying why these were installed so I am looking for a regulation/best practice in this instance
-Mike