Cryogenic liquids are often transported using specific types of tubing that need to meet the requirements for maintaining structural integrity and functionality in a cryogenic environment. Here are some key facts about cryogenic liquid piping:
Pipe Material
Low-temperature high-strength steel: carbon monomanganese is used as the material, and a small amount of nickel-chromium is added to improve the low-temperature toughness of the steel. This material has high strength and high temperature resistance, and is suitable for use in spherical tanks and cryogenic pressure vessels for various engineering applications.
Low-carbon aluminum calming steel: With silicon-manganese as the main component, an appropriate amount of aluminum and fine grains are added to improve the low-temperature toughness and aging performance of steel. Most of the low-temperature steels used in China belong to this category.
Austenitic stainless steel: It has a stable face-centered cubic lattice structure, good toughness, low temperature resistance, and no loss of toughness at a low temperature of -196 °C. Common austenitic stainless steels include 304L and 316, which are suitable for liquefaction, storage and transportation of natural gas, and cryogenic equipment for liquid nitrogen.
Nickel-based low-temperature steel: With nickel as the main element, the low-temperature toughness will also improve as the nickel content increases. This steel can be used in low-temperature equipment at -40~-196°C.
Pipeline Structure
High vacuum insulation structure: cryogenic liquid pipelines often use high vacuum insulation structures, such as cryogenic liquid pipelines provided by Jiangsu Kewell Refrigeration Technology Co., Ltd., which can minimize the consumption of liquid nitrogen in the transportation process and are used for long-distance transportation of ultra-low temperature medium.
Pipe Connections
Push-in flange connection: Push-in flange connection is often used between low-temperature insulation pipes, which makes the flange sweat and frost free, and the thermal conductivity of the metal is greatly reduced.
Pipe Accessories
According to the needs of users, high vacuum multi-layer insulation low temperature stop valve, check valve, emergency shut-off valve, filter, venting system and other components can be added to the low temperature insulation pipe.
Pipeline Applications
Cryogenic liquid pipelines are mainly used to transport cryogenic liquids such as LHe, LH2, LAr, LO2, LN2, LNG, etc., and are widely used in ultra-low temperature medium transportation in aerospace industry, machinery manufacturing industry, food processing, biology, animal husbandry, scientific research units and other industries.
To sum up, cryogenic liquid pipelines need to choose materials suitable for low temperature environments, such as low temperature high strength steel, low carbon aluminum calm steel, austenitic stainless steel and nickel low temperature steel. These pipes are usually constructed with high vacuum insulation to improve insulation and reduce the consumption of liquids during transportation. When it comes to pipe connections and accessories, special requirements for low temperatures are also taken into account.
