Low alloy steel container for pressurised liquefied natural gas - using an ultra-high strength low alloy steel with reduced nickel content but high tensile strength and good fracture toughness

摘要

A container for storing pressurised liquified natural gas (LNG) at a pressure of between 1035 and 7590 kPa and a temperature of between -123 to -62[deg]C is constructed from an ultra-high strength low alloy steel containing less than 9% wt nickel and with a tensile strength greater than 830 MPa and a ductile to brittle transition temperature (DBTT) lower than about -73[deg]C. Also claimed is a container constructed by joining together several discrete plates of the ultra-high strength low alloy steel, where the joints have a tensile strength greater than about 900 MPa and a DBTT lower than about -73[deg]C. Also claimed is a marine vessel for transporting pressurised liquefied natural gas (PLNG) including at least one container constructed as above. Also claimed is a method of transporting PLNG at these pressures and temperatures by (a) delivering the PLNG to a marine vessel with at least one storage container as above, and (b) propelling the marine vessel across a body of water to an import terminal. Also claimed is a system for processing natural gas to produce PLNG at the given pressures and temperatures, where the processing plant contains a number of containers as described.