The Invisible Powerhouse: Liquid CO2's Uses and Major Manufacturing Methods

Have you ever stopped to think about the magic behind a perfectly chilled beverage, the fire extinguisher hanging on the wall, or the delicate components in your smartphone? The answer might surprise you: it could all be thanks to liquid carbon dioxide.

This fascinating substance plays a surprisingly vast role in our everyday lives. From keeping food fresh to ensuring our safety in emergencies, liquid CO2 is a true hidden powerhouse. Let's dvelve deeper into the world of liquid CO2 and explore its diverse applications.

Introduction

Liquid carbon dioxide is a versatile player in many industries. In the food world, it keeps things cool, acting as a refrigerant for freezing and chilling everything from ice cream to meats. It's also the secret behind the fizz in your favorite drinks by adding carbonation. Even water treatment gets a boost from liquid CO2. Beyond food and beverages, this liquid form of carbon dioxide has industrial applications. It helps test the durability of airplane and electronic parts at very low temperatures. In oil and gas operations, it can stimulate wells for better production. It even plays a role in controlling chemical reactions in various processes.

Fire safety is another area where liquid CO2 shines. Its non-flammable nature makes it a popular choice for fire extinguishers, both portable and built-in systems, to quickly extinguish flames. So next time you enjoy a bubbly drink, think about the many ways liquid CO2 keeps things running smoothly, from your kitchen to industrial freezers and even firefighting!

Manufacturing Method

• Carbon dioxide (CO2) is a major product of alcohol fermentation. In the fermentation process, carbon dioxide bubbles that traverse through the mash layer absorb alcohol vapors along with its volatile impurities. The fermentation gases comprise carbon dioxide, alcohol vapors, air, water vapor, alcohols, aldehydes, organic acids, and complex esters. Evaporation-induced losses of alcohol vary depending on its concentration and the fermentation temperature. At a temperature of 30°C, the typical alcohol losses average to 0.74% of the alcohol content present in the mash.

• The fermentation gases are directed into alcohol catchers, where they are absorbed by water and reintroduced into the matured mash as a water-alcohol mixture, with concentrations ranging from 1.5% to 7% by volume. Once devoid of Ethyl Alcohol and its impurities, the fermentation gases are either routed to the Carbon Dioxide production facility or released into the atmosphere.

• To generate liquefied carbon dioxide from fermentation byproducts, it is necessary to cleanse the gas of liquid droplets and organic impurities while preventing air ingress into the gas stream. The purified and dehydrated carbon dioxide is then conveyed to the cooling section of the facility for further liquefaction. However, the quality of the resultant carbon dioxide from this raw material may not consistently meet consumer standards.

• Modern technology adopts a two-step purification process for carbon dioxide. Initially, it undergoes adsorption purification using activated charcoal columns following the initial compression stage. Subsequently, it undergoes further adsorption purification and dehydration, first in a silica gel adsorber and then in a zeolite adsorber for enhanced drying.

• The fermentation gases are initially directed from the fermentation vessels to a foam catcher and then to an alcohol catcher, where they undergo washing with water to eliminate organic impurities and are subsequently cooled. This purified gas is then conveyed to a water ring compressor for further purification and cooling before undergoing compression to a pressure of 0.5 MPa in the initial stage of a three-stage compressor, followed by entry into a refrigeration unit. Oil separators are installed both before and after the refrigeration unit to purify and dry the carbon dioxide.

• Subsequently, the gas undergoes purification using activated charcoal in two adsorbers, with one operational while the other undergoes regeneration using heated carbon dioxide produced during throttling. From the adsorbers, the carbon dioxide proceeds to the second stage of the compressor, where it is compressed to a pressure of 2.4…2.5 MPa before passing through the refrigeration unit and an oil separator, then entering the third compressor stage. Here, the gas, compressed to approximately 7 MPa, undergoes further purification and drying through a series of adsorbers containing silica gel and zeolite.

• In the condenser, following the third compression stage, the gas condenses, releasing heat. The resulting liquefied carbon dioxide is transferred through a high-pressure receiver into steel cylinders placed on scales. Alternatively, overcooled liquefied carbon dioxide can be produced and stored without the use of cylinders. In this process, liquid carbon dioxide is throttled from 6.5 to 7.0 to 0.8 to 1.2 MPa, resulting in an emulsion state. The liquid and gaseous phases are separated in a vortex distributor, with the gaseous phase constituting about 47%.

• The liquid carbon dioxide flows through circular channels of the vortex chamber to a separation vessel and then to a storage vessel, isothermal storage, or a transport isothermal reservoir. The gaseous phase is directed through central openings of the vortex chamber and then through corresponding communication channels to a mixer, where it combines with the gas supplied by the first stage of the compressor before proceeding to the second stage.

• The level of liquid carbon dioxide entering the isothermal storage is monitored by a level indicator, and pressure is measured by a pressure gauge, with the maximum filling of the isothermal storage being 85…90% of the geometric volume. Parameters of the liquid carbon dioxide in the isothermal reservoir include a pressure of 0.8 to 1.2 MPa, a temperature ranging from -43.5 to -33.3 °C, a heat of vaporization of 326 to 309 kJ/kg, and a density of 1130.8 to 1087.8 kg/m³.

Cryocap XLL Process

• The Cryocap XLL Process is an industrial technique devised to compress, cool, and refine raw CO₂ streams from initial units. This is a process owned by Air Liquide Engineering & Construction. It follows a sequential procedure, commencing with the compression of CO₂ feed gas via a feed/recycle compressor. Following this, the compressed gas undergoes drying at an intermediate pressure prior to a secondary compression phase. Then, the compressed gas is cooled and directed towards the cold process.

• Within this cold process, the high-pressure, dry CO₂ is cooled and split into various streams. One stream undergoes distillation within the Stripping Column to yield liquid CO₂ product, which is subsequently dispatched to the unit's battery limits. The remaining streams are expanded to different extents and vaporized within the main heat exchanger, providing the required refrigeration load for CO₂ liquefaction. Post-vaporization, these streams are recycled at ambient temperature back to the feed/recycle compressor. This unique setup enables both feed gas compression and refrigeration to be handled by a single compressor, establishing a self-refrigerated cycle.

• The Cryocap XLL process demonstrates environmental friendliness concerning health, safety, and the environment (HSE) as it eliminates the necessity for toxic or flammable external refrigerants such as ammonia or propane. Moreover, employing a single compressor for both feed and cycle operations leads to a compact and cost-effective solution in terms of capital expenditure.

 

Source: Air Liquide Engineering & Construction

Major Applications of Liquid Carbon Dioxide

1. Food & Beverages

Pressurized CO2 plays a crucial role in the food industry, serving as a versatile tool for refrigeration, preservation, storage, and softening processes. Liquid CO2 serves as a vital cryogenic cooling agent, maintaining a consistent temperature for food preservation and during the transportation of ice cream due to its high volumetric cooling capacity. Additionally, compressed CO2 gas is integral in the production of soft drinks, where it is utilized to carbonate beverages, replacing natural fermentation methods. Bottled drinks are preserved and softened using pressurized CO2, ensuring their quality and shelf life. Liquid CO2's versatility extends to its use as a solvent, facilitating the removal of caffeine from coffee. Overall, the significance of pressurized CO2 in the food industry cannot be overstated, impacting various aspects of food processing and beverage production.

1. Fire Extinguishers

Liquid carbon dioxide serves as an effective fire extinguisher due to its non-flammable properties. It operates by depriving flames of oxygen, the essential gas for combustion. Particularly suited for electrical fires, extinguishers containing liquid carbon dioxide eliminate oxygen to extinguish the fire while also cooling the burning surfaces, thereby preventing additional damage.

1. Oil & Gas

In the process of oil recovery, the liquid is injected into oil wells, where it blends seamlessly with the oil. This blending reduces the viscosity of the oil, making it less thick and allowing it to flow more readily towards the extraction point.

Market Outlook

The food and beverage industry are a major driver for liquid carbon dioxide (CO2) due to its versatility. CO2 not only carbonates beverages but also acts as a natural preservative, extending the shelf life and freshness of food products during storage and transportation. Its inert properties and ability to suppress bacterial growth make it a critical component in food processing and packaging. As consumer demand for packaged and convenient food options continues to rise, the CO2 market within this sector is expected to see significant growth. Furthermore, CO2 plays a crucial role in enhanced oil recovery (EOR) techniques used in the oil and gas industry. By injecting CO2 into existing reservoirs, companies can increase pressure and extract more oil from the rock formations. This method effectively extends the lifespan of oil fields and boosts production rates, driving demand for CO2 in the energy sector.

Liquid Carbon Dioxide Major Global Players

Major players in the Global Liquid Carbon Dioxide market are Punjab Carbonic private Limited, SICGIL India Limited, India Glycols Limited, Prime Gases, Jubilant lifesciences limited, Indo Gulf Corporation, Hangzhou Oxygen Co. Ltd., Messer Group GmbH, Linde Plc, Bangkok Industrial Gas Company Limited (BIG), Messer - AlcoBioFuel Bio-Refinery - IJsfabriek Strombeek JV, Air Products (ACP Belgium), CropEnergies - Tyczka Energie JV, CF Fertilisers UK Ltd, Linde Gáz Magyarország Zrt, and Others.

Conclusion:

Beyond its role in fizzing drinks and keeping food fresh, liquid carbon dioxide (CO2) offers a surprising range of uses. In the oil and gas industry, it even helps extract more resources. Additionally, liquid carbon dioxide functions as a fire extinguisher and can be used to control chemical reactions for safer industrial processes. The liquid carbon dioxide market is poised for significant growth, driven by its expanding role in various industries. From its essential function in carbonating beverages and preserving food to its growing applications in enhanced oil recovery and medical procedures, CO2's versatility and unique properties guarantee its continued relevance. As consumer demand for convenience and efficient production methods rises, the CO2 market is expected to flourish, presenting exciting opportunities for stakeholders across the supply chain.