Old Ships, New Tech & Firsts on the Horizon

Rollover received considerable attention following a serious venting incident at the LNG receiving terminal at La Spezia, Italy in 1971.

What is Rollover ❓ See the second issue 📝

👉 The various reasons for rollover are :

• When there is temperature difference within the liquid.

• If the cargo is stored for a long time without circulation.

• Similar or Compatible cargo stored in one tank.

• If condensate of two or more tank is returned to one tank.

👉 The Effects of Rollover are :

• Increase in the boil off rate up to 10 times than the normal condition.

• Increase or over pressurisation of the tank.

• Lifting of relief valves of the tank.

👉 Measures to prevent rollover are :

• Different density cargo to be stored separately.

• Load tank with equipments such as nozzle (used for shore tanks) to promote mixing.

• Long stoppage to be avoided when loading ship’s tank.

• Boil off rate to be continuously monitored.

Both the tanks on the shore and ships are subjected to rollover, but the possibility of Rollover to take place is higher 📈 in ship tanks due to the size and capability of handling different cargoes in the same tank.