Is flame arrester in a vent line from a vessel considered blocked because of fouling so that a relief valve is needed to protect the vessel from over pressure? If the vapor has water and the flame arrester is not heat traced should the flame arrester be considered blocked due to ice formation during freezing condition?
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Use of flame arrester 1
- Thread starter ing123
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ing123:
The situation can happen. Check with the local Regulatory Body. I know of at least one Province in Canada - for example - where the PSV is required on any HP FKOD where the design pressure can exceed 15 psig in any case, as it would be for any "vessel". Code does require that all potential cases causing overpressure are considered.
I guess there has been one too many fibreglass FKOD's popping like a balloon due to a plugged flame arrestor.
By all means trace the arrestor. You can probably avoid the PSV if you do.
Regards,
SNORGY.
The situation can happen. Check with the local Regulatory Body. I know of at least one Province in Canada - for example - where the PSV is required on any HP FKOD where the design pressure can exceed 15 psig in any case, as it would be for any "vessel". Code does require that all potential cases causing overpressure are considered.
I guess there has been one too many fibreglass FKOD's popping like a balloon due to a plugged flame arrestor.
By all means trace the arrestor. You can probably avoid the PSV if you do.
Regards,
SNORGY.
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>>Flame arrestor on the vent line off a loading arm - what should one take as the flowrate through the arrestor? Is it in any way linked to the loading flow rate? <<
Yep. Exactly.
The API expresses three modes for venting calculations:
1. Inflow/Outflow, where displaced gas is vented or air(or blanketing gas) replaces any change in liquid volume in the tank.
2. Sudden cooling of a tank. Rapid quenching by a thunderstorm on a hot day can chill the atmosphere in a tank so quickly that the tank can can collapse. This is a greater flowrate than pump/drain relief.
3. Fire case. Relief of vapors genetrated by direct contact of flame with the wetted walls of a vessel. The code gives consideration to the level in the vessel, the configuration of the vessel with regard to the area of the tank that can be exposed to fire,insulation, and the properties of the liquid inside.
For a vent-line off a loading arm, only the flowrate would be a valid consideration. 1 gpm in =0.1337 CFM gas vented.
Yep. Exactly.
The API expresses three modes for venting calculations:
1. Inflow/Outflow, where displaced gas is vented or air(or blanketing gas) replaces any change in liquid volume in the tank.
2. Sudden cooling of a tank. Rapid quenching by a thunderstorm on a hot day can chill the atmosphere in a tank so quickly that the tank can can collapse. This is a greater flowrate than pump/drain relief.
3. Fire case. Relief of vapors genetrated by direct contact of flame with the wetted walls of a vessel. The code gives consideration to the level in the vessel, the configuration of the vessel with regard to the area of the tank that can be exposed to fire,insulation, and the properties of the liquid inside.
For a vent-line off a loading arm, only the flowrate would be a valid consideration. 1 gpm in =0.1337 CFM gas vented.
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