What Is Liquid CO2 Used For?

Liquid CO2 is mainly used for food and beverage production, though it’s also common in chemical manufacturing, welding, and cleaning. 

In this guide, we will go over the use cases of liquid carbon dioxide in more detail. Besides typical uses, we will cover a few liquid carbon dioxide uses that – unless you really know a lot about liquid CO2 – you’ve probably never heard of. 

Let’s get started! 

Liquid CO2 is Valuable in Food and Beverage Manufacturing

Carbon dioxide gives sodas and sparkling beverages their signature fizz through the process of carbonation. Here’s how it works:

1. Dissolving CO2 – Carbon dioxide gas is forced into the liquid (usually water or flavored syrup) under high pressure, which increases the solubility of CO2.
2. Formation of Carbonic Acid – Some of the CO2 reacts with water to form carbonic acid (H₂CO₃), giving the drink a slightly tangy taste.
3. Sealing the Pressure – The beverage is sealed in airtight containers (bottles or cans) to maintain pressure and keep CO2 dissolved in the liquid.

Food manufacturers also use CO2 as a powerful cooling agent in flash-freezing processes to help maintain food quality and extend shelf life. This process happens in four stages:

1. Injection of Liquid CO2 – Liquid carbon dioxide is released into a freezing chamber or sprayed directly onto the product.
2. Rapid Expansion & Cooling – When liquid CO2 expands into a gas, it absorbs heat from its surroundings, causing an instant temperature drop.
3. Formation of Dry Ice Snow – Some CO2 solidifies into dry ice (-78.5°C / -109.3°F), which further cools the product by direct contact.
4. Fast Freezing – The intense cold freezes the product quickly, forming small ice crystals, which helps preserve texture and prevent damage.

The main reason liquid CO2 is used for flash-freezing is its ability to form smaller ice crystals than other processes, which helps prevent texture degradation. Liquid CO2 is also non-toxic, which makes it suitable for food-related applications. 

Liquid CO2 in Chemical Processing

Liquid CO2 is used as a raw material to produce essential chemicals like methanol and urea.  These are the building blocks of countless products we use daily, such as plastics, paints, and carpets.

As a reactant, CO2 can be used for chemical processes, such as:

• Carbonation Reactions – Used to produce carbonates and bicarbonates (e.g., sodium bicarbonate, used in baking soda).
• Polymer Production – Helps synthesize polycarbonates and biodegradable plastics (e.g., CO2-based polyols for polyurethane production).

CO2 can also be used as a solvent in the following processes:

• Essential Oil Extraction – Extracts flavors, fragrances, and pharmaceutical compounds.
• Dry Cleaning – Replaces toxic solvents in textile cleaning.

Liquid CO2 in Industrial Processes

The welding industry has many liquid carbon dioxide uses. For example, CO2 acts as a component of shielding gas mixtures, protecting the weld area from contamination and oxidation. This results in stronger and cleaner welds that meet the strict quality standards that many welding projects must adhere to.

If used alone, CO2 produces a strong but somewhat rougher weld with increased spatter. That’s why welders often choose a mixture of 75-80% argon and 20-25% CO₂ for a more stable arc, reduced spatter, and better weld quality.

Finally, industrial cleaning operations often rely on dry-ice blasting, where solid CO2 pellets created from liquid CO2 are used to clean equipment and surfaces without leaving any residue. This method is particularly useful in food processing facilities where cleanliness is essential.

Safety and Environmental Applications of Liquid CO2

Liquid CO2 is used in many safety procedures and environmentally friendly applications, such as:

• Fire suppression: liquid CO2 is especially effective for electrical fires and situations where water-based systems aren’t suitable.
• Carbon capture and storage (CCS):  this process helps reduce greenhouse gas emissions by first capturing CO2 gas from industrial processes. The gas is then compressed into a liquid or supercritical state for transport and storage deep underground.
• pH adjustment: water treatment facilities use liquid CO2 to ensure safe drinking water for communities. It’s a more environmentally friendly alternative to other chemical options like chlorine.

Medical Uses of Liquid CO2

Liquid CO2 uses extend to many medical processes. 

For example, doctors use it in cryosurgery to remove unwanted tissue and treat skin conditions.

Liquid CO2 can also be turned into gas to assist laparoscopic surgery, specifically for ​​insufflation. CO2 is used to inflate body cavities (e.g., abdomen) to provide better visibility and working space for surgeons.

Medical equipment sterilization also heavily relies on CO2. Supercritical CO2 (formed from liquid CO2 under high pressure and temperature) is used to sterilize delicate medical instruments and implants without damaging sensitive materials.

Specialized Uses of Liquid CO2

Liquid CO2 is used in virgin olive oil extraction and heating systems, as well.

It really is a versatile material!