STEAM RELEASE TO THE FLARE SYSTEM 2

[roker]

Hello,

In order to avoid steam vapor plume, from a third stage vacuum system ejector outlet, to be seen in the atmosphere, it was advised to connect this steam to the flare system.
To me it seems a wrong idea but I have not strong reasons to convince it.
Did someone faced such a situation and what were the reasons to do it or avoid from doing it.

Thanks and regards,
roker

 

[georgeverghese]

You've got to have simulation information on max backpressure seen at the the proposed flare tie in location for the various operating and emergency scenarios and see if you've got all the credible combination scenarios covered. Doesnt sound like you're there yet on this evaluation.

On the other hand, another option would be to route this stream to the sour water stripper if your stage 3 ejector exit pressure is adequate? - that would address corrosion issues ( H2S / ammonia ) also.

 

[EmmanuelTop]

Depending on the maximum discharge pressure for the 3rd stage ejectors (typically slightly above atmospheric pressure), you shouldn't consider directing this stream to flare if there are any scenarios during which this pressure (backpressure from the flare) would be exceeded.

Vacuum Distillation Units (VDU) in petroleum refineries have this stream routed to VDU furnace, to a separate burner, in majority of VDU designs I am familiar with. Depending discharge gas composition and the circumstances in your plant, you may be forced to use other solution. Sour water stripper, as mentioned above, or an incinerator, or off-gas compression/recovery system , might be the options.



Dejan IVANOVIC
Process Engineer, MSChE