Liquid Nitrogen, LN2 gas-supplied by DSW
Liquid nitrogen is primarily produced through the process of air separation.
Air separation plants utilize techniques such as liquefaction and distillation to separate air components, including nitrogen, oxygen, and argon.
During the air separation, air is compressed and cooled to very low temperatures, typically using cryogenic refrigeration systems.
As the air cools, it undergoes liquefaction, causing it to transition into a liquid state. The process involves passing the liquefied air through a distillation column, separating constituent gases based on their distinct boiling points.
DSW delivers LN2 to our customers using specialized cryogenic tankers and sends it to their premises for utilization in high-volume applications. Upon arrival, our customers store it in vacuum-insulated vessels that are specifically designed for cryogenic liquids. These vessels have the capability to store a sufficient supply of liquid nitrogen gas for several days. The stored liquid nitrogen can be conveniently utilized on demand, either in its liquid form or as a gas, per the customers’ requirements. This storage system ensures a reliable and continuous supply of liquid nitrogen, catering to the diverse needs of our valued customers.
Liquid nitrogen possesses several distinctive features, including:
- Refrigerated Liquefied Gas: To obtain liquid nitrogen, we subject nitrogen gas to the process of liquefaction, resulting in a cryogenic liquid. We carefully maintain this liquid at extremely low temperatures to ensure it remains in its liquid state.
- Boiling Point -196°C: Liquid nitrogen’s boiling point is extremely low, at -196 degrees Celsius (-321 degrees Fahrenheit). When exposed to warmer temperatures, this characteristic lets it evaporate rapidly into a gas.
- Gas/Vapour Heavier Than Air: Nitrogen gas, including the vaporized form of liquid nitrogen, is heavier than air. This property causes it to displace oxygen in confined spaces, potentially leading to oxygen deficiency and asphyxiation risks if not properly handled.
- Odourless, Colorless, and Non-Toxic: Liquid nitrogen lacks any distinctive odor and color, making it imperceptible to human senses. Additionally, it is considered non-toxic, posing minimal immediate health hazards in its liquid or vapor form.
- Chemically Inert at Ambient Temperatures: Nitrogen is chemically inert under normal ambient conditions, meaning it does not readily react with other substances. This inertness makes liquid nitrogen suitable for various applications requiring a non-reactive environment.
Argon is included in the nitrogen
Application and use
Liquid nitrogen is a cryogen in numerous applications requiring extremely low temperatures or rapid temperature reduction.
The inherent inert nature of gaseous nitrogen makes it suitable for scenarios where protecting substances from oxidation, combustion caused by atmospheric air, or moisture contamination is imperative.
Nitrogen finds application in various typical scenarios, including:
Artificial Insemination: Nitrogen gas is commonly used for storing semen samples for cattle in the field of artificial insemination (AI). Nitrogen maintains semen samples at ultra-low temperatures, typically around -196 degrees Celsius (-321 degrees Fahrenheit). This extreme cold effectively preserves the viability of sperm cells for an extended period.
Blanketing and inserting: Nitrogen is commonly used to maintain a dry and inert atmosphere over chemicals during storage, reactions, or processing. This practice is widespread in various industries, including pharmaceuticals, chemicals, electronics, and food processing.
Controlled atmospheres: The atmosphere and ambient temperature surrounding naturally respiring products, such as fruit, are carefully regulated to provide ideal conditions for long-term storage. The management of these factors aims to optimize the storage environment and extend the shelf life of the products.
Electronics: LN2 is commonly employed in printed circuit board (PCB) reflow and wave ovens for inerting purposes. Its primary function is to prevent oxidation and facilitate the use of weaker fluxes, which decompose more easily without leaving behind any residue.
Food freezing: Liquid nitrogen freezes food quickly, producing a higher-quality product than conventional refrigeration.
Food inserting: Liquid nitrogen (LN2) is employed in the brewing, soft drinks, and wine-making sectors to create an oxygen-free environment and reduce the presence of water in the respective products.
Food packaging: Liquid nitrogen is utilized in modified atmosphere packaging to extend the shelf life of products without the need for vacuum packaging, artificial preservatives, or freezing. Introducing liquid nitrogen into the packaging environment reduces the oxygen content, inhibiting the growth of spoilage microorganisms and enhancing product preservation.
In freeze-drying, substances dissolved in water or organic solvents are frozen into solid particles or droplets. Subsequently, a controlled amount of heat and a vacuum environment are employed in the freezing chamber to facilitate moisture removal through sublimation. This method allows preserving delicate materials while maintaining their structural integrity and desired properties.
Glass Manufacturing: The float glass manufacturing process uses nitrogen and hydrogen. These gases are integral in producing flat glass, where liquid glass is delicately floated on a molten tin bath. This technique ensures the achievement of a flawlessly smooth and high-quality glass product with excellent optical properties.
Heat treatment: Heat treatment processes often involve using pure nitrogen as a protective atmosphere for highly reactive metals. When air is exposed, these metals react with oxygen and form oxide layers.
Nitrogen atmosphere can enhance the mechanical properties of metals during heat treatment. It can improve the treated metal’s hardness, strength, and wear resistance, making it suitable for applications that demand high-performance materials.
Metals Nitrogen is used in iron and steelworks applications for degassing and metal-stirring, purging, cooling, slag splashing, gas knives, and as a carrier gas for injecting de-sulphurising compounds. It is also used for aluminium-extrusion inerting.
Pipe-freezing Repairs: Pipe freezing is a technique for temporary repairs or modifications to a pipe containing liquid. Liquid N2 is often used to freeze a fluid plug on each side of the section of the pipe that needs to be opened or worked on. It’s important to note that pipe freezing is a temporary solution and should not be considered a permanent repair method.
Purging: Purging refers to utilizing nitrogen gas to displace or remove unwanted gases, vapours, or liquids from various systems or containers. N2 creates an inert atmosphere within reactors and storage tanks, eliminating oxygen and other reactive gases and minimizing the risk of unwanted reactions or combustion. Nitrogen purges vessels and pipelines of flammable or toxic gases and vapours. Displacing these hazardous substances with inert nitrogen makes the environment safer for maintenance, inspection, or entry.
Shrink-fitting: Liquid nitrogen gas is used in a cryogenic shrink-fitting process. This technique uses the extreme cold of liquid nitrogen to shrink components, making them compact enough to be inserted into another element or assembly.
Sample storage: LN2 is widely used to store medical and research samples, including blood, plasma, and semen, safely. Liquid nitrogen provides extremely low temperatures, maintaining samples at or below -150 degrees Celsius (-238 degrees Fahrenheit). Such low temperatures effectively halt biological activity and preserve the integrity of the samples for long-term storage.
Liquid Nitrogen Supply Model
Liquid phase nitrogen can be supplied in pre-filled liquid cylinders and refillable Dewars.
For more extensive supply requirements, liquid nitrogen can be delivered to small onsite cryogenic vessels (MicroBulk) or large-scale cryogenic vessels (bulk tanks).