MMcLean
Chemical
- Jul 21, 2003
- 25
- 0
- 0
We are involved in a small LNG storage and tanker loading facility and need to review the likelihood of rollover in the tanks. Are there any guidelines to this phenomenon?
The tanks in question will be vacuum insulated tanks (VIT’s). The tanks will be approximately 5 m diameter and 36 m long (external dimensions) with a nett volume of 500m3 (224 tonnes). There will be a total of 5 tanks. The ‘typical’ configuration of tanks of this size and type does not have temperature gradient measurement through the tank, as would occur in larger storages (spheres etc).
Storage / Holding pressure will be around 100 kPag (Ts= -154C).
The tank storage facility is filled from an existing LNG liquefication plant which will operate on a campaign basis. One tank at a time will be filled. The liquid from the plant will be subcooled relative to the tank contents (T= -164C). Top and bottom filling is possible.
Tanker filling will occur from a different tank to the one being filled. Tank loadout includes a continuous recirculation loop back to the tanks, so the return flow should be slightly warmer (due to heat inleak) relative to the tank contents. At present our concept has return to the tank bottom only.
The subjective assessment to date is that rollover is unlikely for a plant of this scale. However I would like a more considered analysis. Are there any guidelines to this phenomenon? Is scale of operation relevant at all (tank size, recirculation rate)?
Mark McLean
WorleyParsons
The tanks in question will be vacuum insulated tanks (VIT’s). The tanks will be approximately 5 m diameter and 36 m long (external dimensions) with a nett volume of 500m3 (224 tonnes). There will be a total of 5 tanks. The ‘typical’ configuration of tanks of this size and type does not have temperature gradient measurement through the tank, as would occur in larger storages (spheres etc).
Storage / Holding pressure will be around 100 kPag (Ts= -154C).
The tank storage facility is filled from an existing LNG liquefication plant which will operate on a campaign basis. One tank at a time will be filled. The liquid from the plant will be subcooled relative to the tank contents (T= -164C). Top and bottom filling is possible.
Tanker filling will occur from a different tank to the one being filled. Tank loadout includes a continuous recirculation loop back to the tanks, so the return flow should be slightly warmer (due to heat inleak) relative to the tank contents. At present our concept has return to the tank bottom only.
The subjective assessment to date is that rollover is unlikely for a plant of this scale. However I would like a more considered analysis. Are there any guidelines to this phenomenon? Is scale of operation relevant at all (tank size, recirculation rate)?
Mark McLean
WorleyParsons
