LNG handling |||
LPG handling||| Other Gas products|||
Fire & Safety|||
Emergency response |||
Carrying bulk liquefied gases by semi pressurized ships
These vessels are fitted with a refrigeration plant that
provides a fully refrigerated ability while having a high
design pressure for the cargo tanks (Pressure vessels),
albeit below that required for fully pressurised carriage.
The tanks are cylindrical in shape and of a thinner
construction than the pressurised vessels.
Semi-pressurised, semi-refrigerated ships (which are
now quite rare) ranged up to 5,000 m3 in size. Their construction is based on carrying propane at a pressure
of 8.5 kg/cm2, and a temperature of -10°C.
Semi-pressurised, fully-refrigerated ships generally range
up to 15,000 m3. They can be designed to carry the full
range of cargoes in cylindrical or spherical tanks and are
designed for a minimum service temperature of -48°C
and a working pressure of approx 5 to 8 kg/cm².
The reliquefaction plant on these vessels generally has a
substantial capacity and can, if required, load the cargo
as a gas and then reliquefy it onboard.
They are able to heat or cool the cargo during loading
operations, or while at sea, and are also able to raise
the temperature of the cargo when discharging.
Where a reliquefaction plant is fitted it will allow a
reduction in the wall thickness of the tanks.