Fluids Commonly Used in Cryogenics

Cryogenics observes the production and behavior of materials at extremely low temperatures. To provide a better idea of how this science works, this article will explore various examples of fluids used in cryogenics.

What Are Cryogenic Fluids?

Liquids with boiling points below minus 130 degrees Fahrenheit are classified as cryogenic. Cryogenic fluids often provide low temperatures for frozen storage, research and experimentation purposes.

A cryogenic substance can fall into one of three groups:

1. Flammable gases: Certain cryogenic liquids — such as methane, hydrogen and liquefied natural gas — produce gas that can burn in the air. These are classified as flammable gases.
2. Inert gases: Inert or noble gases don’t undergo any significant chemical reactions, like burning or combustion, with other substances. Some examples are helium, nitrogen, neon, argon and krypton.
3. Oxygen: Many materials classified as “non-combustible” will burn when exposed to liquid oxygen. Organic materials can have an explosive effect in the presence of liquid oxygen. Therefore, there are separate risks and handling precautions to consider with liquid oxygen.

Risks Associated With Cryogenic Substances

The careful and safe handling of cryogenic liquids is crucial. These substances can pose both physical and human health risks, including:

• Pressure buildup
• Embrittlement
• Fire
• Explosion
• Frostbite
• Asphyxiation

Two main hazards are associated with cryogenic substances — very low temperatures and vaporization.

Most metals can withstand extremely cold temperatures. However, materials like plastic, rubber and carbon steel can weaken and fracture when exposed to these conditions. Cryogenic fluids also have cold boil-off vapor that can quickly freeze human tissue. Human contact with cryogenic liquids can cause frostbite, cold burns and potentially severe tissue damage. This makes choosing the appropriate container materials a must.

Additionally, cryogenic fluids release large amounts of gas during vaporization. They can generate dangerously large pressures that could rupture a sealed container. Vaporized liquid oxygen can cause other materials to combust. Vaporized liquid hydrogen is extremely flammable when mixed with air. Additionally, the vaporization of cryogenic substances — excluding oxygen — can cause asphyxiation. Multiple pressure relief devices are typically necessary when working with pressurized cryogenic containers.

Best Practices for Handling Cryogenic Liquids

With the above risks in mind, cryogenic fluids must be properly stored and controlled to prevent any contact with the liquid or its gases. Handle the containers with extreme caution to avoid drops and spills. Never roll them or tip them on their sides.

Cryogenic liquids should be stored in vessels specifically designed for them. These tanks should be double-walled and thoroughly insulated. Remember to keep cryogenic containers and tanks away from walkways, elevators and unprotected platform edges. They also shouldn’t be stored in areas where heavy moving objects could strike them.

Personal Protective Equipment (PPE)

When filling, transferring, dispensing and handling cryogenic substances, PPE helps protect the skin from cold burns. It also prevents the liquid from splashing into the face and eyes. It’s essential to wear the following protective clothing when working with cryogenic fluids:

• Loose-fitting thermal gloves
• Safety goggles
• Face shield
• Lab coat and apron
• Closed-toed shoes
• Long-sleeved shirt and long pants

8 Common Fluids Used in Cryogenics

Here are eight fluids commonly used in cryogenics:

1. Helium

Helium is a colorless and odorless noble gas. It has the lowest boiling point, making it the coldest cryogenic liquid. A temperature as low as minus 269 degrees Celsius is needed to maintain helium’s liquid state. Helium is commonly used in the aerospace industry, serving as a pressurizer for ground and flight fluid systems. The automotive industry also uses helium to test critical components.

2. Hydrogen

Hydrogen is a colorless, odorless and flammable gas. It doesn’t exist in its pure form on Earth — it must be produced from natural gas (steam reforming) or water (electrolysis).

When in liquid form, hydrogen must be stored at 252.8 degrees Celsius. Liquid hydrogen is an increasingly common renewable fuel and energy generation solution. It’s used in various sectors, including space, marine and transportation.

3. Neon

Neon is another prevalent cryogenic refrigerant. This colorless and odorless inert gas has an incredibly high cooling capacity. It has over three times the amount of refrigerating capacity per unit volume than liquid hydrogen. Additionally, it has over 40 times that of liquid helium. Liquid neon has a variety of uses, including:

• High-voltage indicators
• Vacuum tubes
• Lightning arrestors
• Diving equipment
• Television tubes
• Lasers

4. Nitrogen

Liquid nitrogen is one of the most widely used materials used in cryogenics. It’s a tasteless, colorless and odorless inert gas with a boiling point of 196 degrees Celsius. Liquid nitrogen can be extracted from ambient air, making it an affordable and relatively eco-friendly substance.

Liquid nitrogen has a multitude of applications, including:

• Shrinking and welding automotive parts
• Testing electronics
• Cooling food and beverage products
• Creating durable, lightweight aeronautics materials
• Freezing and transporting blood, tissue and other biological samples
• Preserving medicines and biological materials

5. Fluorine

Fluorine is a toxic, pale yellow-green gas with a pungent odor. It’s highly reactive with other elements, excluding light inert gases. It liquidizes into a bright yellow fluid at 188 degrees Celsius, showing similar transition temperatures to nitrogen and oxygen.

Minor fluorine exposure can irritate the skin, eyes and lungs. Severe exposure can have fatal consequences, complicating breathing and damaging the lungs. Fluorine can be stored as a cryogenic liquid and used to make chemicals, pesticides, dyes, lubricants, ceramics and plastics.

6. Argon

Argon is a colorless, odorless inert gas with a boiling point of minus 185.8 degrees Celsius. Though nontoxic, it’s denser than air, making it an asphyxiant in enclosed areas.

While argon is usually stored and transported as a liquid, it’s generally used in its gaseous state. It can be used to fill lamps and double-glass panes. It’s often used in incandescent light bulbs to prevent oxygen from damaging the filament. Welders can also use argon to protect work areas.

7. Oxygen

Liquid oxygen is a reactive, odorless light blue liquid. It converts to a liquid form at 183 degrees Celsius and serves numerous industries and applications.

For instance, the health care industry often uses liquid oxygen since it streamlines transportation and storage. It occupies considerably less space than gaseous oxygen. Additionally, liquid oxygen is a popular oxidant for liquid fuels in rocket and missile propellant systems.

8. Methane

Methane is a flammable, odorless and colorless gas consisting of hydrogen and carbon. It has a boiling point of minus 162 degrees Celsius and a melting point of minus 182 degrees Celsius. Methane is typically used to manufacture organic chemicals. It can also serve as fuel to produce light and heat.

Practice Safe Fluid Handling With Filters From Chase Filters & Components

When working with materials like hydrogen and oxygen, it’s important to have durable, high-quality filters. At Chase Filters & Components, we have a broad selection of filter types and sizes customizable to your needs. We have high-pressure filters for gas, oxygen, water and other substances. We serve a variety of industries, from aerospace and automotive to oil and gas.

Find the filtration solutions you need at Chase Filters & Components. Browse our products to find the right filters for your requirements, or reach out to us with any questions.

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