Liquefied natural gases (LNG) are refrigerated gaseous chemicals that have been converted to fluids for ease of storage and transportation. The conversion process involves treating natural gases to remove precipitates and concentrates, and undesirable gas components such as carbon dioxide (CO2). Resultant gases are then cooled to temperatures below freezing, to reduce the pressure requirements of gas storage and transport components. This diminishes the combustibility of natural gases and the volumetric requirements of cryogenic vessels, as LNGs display denser particle concentrations with volumes of up to 600 times lower than their gas counterparts. However, liquid gas storage is not without its challenges.
This article will explore the challenges of liquid gas storage in more detail:
Liquid Gas Storage Challenges: Temperature & Stability
Liquid gases such as oxygen (O), nitrogen (N), and argon (Ar) must be stored at temperatures of below -196°C (-321°F) to maintain their compressed, fluidic properties. Raised temperatures will cause LNGs to agitate and become gaseous in unsuitable volumetric containers, which could dangerously increase the pressure within a liquid gas storage cryogenic vessel.
Liquid gas storage applications typically install contingencies for pressure-related emergencies, including relief and safety shut off valves to avoid catastrophic component failure – and this is a rare occurrence. Temperatures are monitored using careful measurement instrumentation and maintained using a careful matrix of materials, including insulation and pressure-vessel grade steel.
However, steel for liquid gas storage must conform to distinct elemental compositions to meet temperature-sensitive requirements. Common steel alloys and many pressure vessel steels exhibit brittle-ductile phase transitions, which describes a tendency to crack or shatter at low temperatures. This occurs at a molecular level, where atoms are unable to slip or deform as steel cools, causing significant material embrittlement. There is a significant risk of combustion if liquid gas storage and transport components experience large losses in ductility.
Liquid Gas Storage Solutions
Cryogenic steel plates for liquid gas storage were specifically designed to overcome these challenges. They are fabricated using 9% nickel steel grades, which offer improved atomic slip structures for steel alloys. This unique temperature characteristic comes at no expense to the mechanical strengths and weldability of conventional steel materials, enabling manufacturers to fabricate cryogenic steel plates into cylindrical shapes for transport pipes and vessels.
Liquid Gas Storage Products from Masteel
Masteel are leading suppliers of cryogenic steel plates for liquid gas storage applications. We provide a range of 9% nickel steels with multiple specifications, each with outstanding mechanical strengths and high ductility at application-specific temperatures.
The cryogenic steel grades we supply include:
- ASTM A553 Type 1;
- ASTM A553 Type 2;
- ASME SA553 Type 1;
- ASME SA553 Type 2;
- ASTM A353;
- ASME SA353.