Routing of Vacuum Unit Off-gas
Routing of Vacuum Unit Off-gas
(OP)
My friends,
We have many distillation towers running under vacuum. The vacuum can be pulled by jets, liquid ring pumps, vacuum pumps, or combinations of these. The design is usually for some small air engress, typically less than 100 lbs/hr. The off-gas typically goes to an incinerator or to atmosphere, but in no cases to the plant flare system. This decision is probably driven by concern about the possibility of air going to flare.
The operations manager wants to reroute the vacuum unit off-gas to flare. I am doing a survey of practices elsewhere. How are you guys handling vacuum unit off-gas in your units?
best wishes,
Sean
We have many distillation towers running under vacuum. The vacuum can be pulled by jets, liquid ring pumps, vacuum pumps, or combinations of these. The design is usually for some small air engress, typically less than 100 lbs/hr. The off-gas typically goes to an incinerator or to atmosphere, but in no cases to the plant flare system. This decision is probably driven by concern about the possibility of air going to flare.
The operations manager wants to reroute the vacuum unit off-gas to flare. I am doing a survey of practices elsewhere. How are you guys handling vacuum unit off-gas in your units?
best wishes,
Sean





RE: Routing of Vacuum Unit Off-gas
RE: Routing of Vacuum Unit Off-gas
Is the driver to reduce fuel gas consumption for the flare header? Seams reasonable but maybe you need to get some GC samples to determine the composition of the streams. You also have to consider how you will handle startup where a large amount of air could be introduced. I would like to say we do this, but we vent everything no flare or incinerator.
Regards
StoneCold
RE: Routing of Vacuum Unit Off-gas
Please help me to collect a few more examples and understand the reasoning (could be back pressure just as much as fears about O2). The start-up consideration is a good thought.
best wishes,
sshep