Dear All,
We have Rich MEG (60% MEG+ 40% Water) storage tank which is blanketed with nitrogen.
Tank design pressure is 0.15 barg (API 650 tank) and design liquid level is 9300 mm. Operating pressure 0.05 barg.
Tank is cone roof type with FO of emergency hatch is at 12900 mm. If tank is overfilled till FO of emergency hatch, this will be over pressured and tank will fail.
To prevent over pressure due to overfilling of tank, there are two proposal:
(1)To provide a overflow line above tank design level and a liquid seal will be provided on overfilling line. Overflow line will be a looped line.
(2) Instrumented protection (SIL 1) will be provided to prevent overfilling.
Will option 1 work for the service with N2 blanketing ?
Please advise.
Regards,
Chem2013