The demand for efficient and reliable CO2 liquefaction is growing across a wide range of industries. Carbon dioxide that is captured from industrial processes, biogas production or other sources can be purified and converted into liquid CO2, making it easier to store, transport and reuse.
Modern CO2 liquefaction systems provide an effective way to turn gaseous carbon dioxide into a valuable liquid product. Especially with increasing attention on carbon recovery and reuse, compact and modular liquefaction technology is becoming increasingly relevant.
What is CO2 Liquefaction?
CO2 liquefaction is the process of converting gaseous carbon dioxide into a liquid state by combining compression, purification and cooling.
Before liquefaction can take place, contaminants and moisture generally need to be removed. The CO2 is then compressed and cooled until condensation occurs. The resulting liquid CO2 can be transferred to an insulated storage tank for later use or transportation.
A well-designed CO2 liquefaction system combines these different process steps in one integrated installation.
How does the CO2 liquefaction process work?
Although the exact configuration depends on the application and gas source, CO2 liquefaction generally consists of several important stages.
First, impurities must be removed from the incoming CO2 stream. The gas is then compressed to the required operating pressure.
Moisture removal is particularly important because water can create operational problems at low temperatures. Drying systems are therefore used before the carbon dioxide enters the liquefaction stage.
During liquefaction, the purified CO2 is cooled until it condenses into liquid form. Non-condensable gases can be separated from the process while the purified liquid CO2 is transferred to a suitable storage tank.
This combination of purification, compression, drying and cooling makes it possible to produce a consistent liquid CO2 product.
Why liquefy CO2?
Turning gaseous carbon dioxide into liquid CO2 provides several practical advantages.
Liquid CO2 has a much higher density than gaseous CO2, making transportation and storage considerably more efficient. Liquefaction can therefore help connect locations where CO2 is generated with industries that require carbon dioxide as part of their production process.
It also creates opportunities to recover CO2 that might otherwise be released.
For example, biogas and biomethane production can generate relatively pure streams of carbon dioxide. Instead of treating this CO2 purely as a by-product, it can be captured, purified and liquefied for further use.
Applications of liquid CO2
Liquid CO2 is used in many different industries. Common applications include:
- Food and beverage production
- Carbonation of beverages
- Food cooling and preservation
- Greenhouse cultivation
- Chemical manufacturing
- Industrial processing
- Carbon capture and utilisation
- Carbon capture and storage
The required purity and liquefaction configuration will depend on the final application. Food-grade CO2, for example, can have different purification requirements than CO2 intended for certain industrial applications.
Modular CO2 liquefaction systems
Modularisation is increasingly important in CO2 recovery projects. Instead of engineering an entire facility from individual components on site, major process steps can be incorporated into compact modules.
This can simplify installation and make it easier to adapt capacity to the amount of available CO2.
A modular CO2 liquefaction plant can also be designed around different CO2 sources. Important factors include the composition of the incoming gas, required liquid CO2 capacity, purity requirements, operating hours and available utilities.
Selecting the right system should therefore be based on the complete project rather than production capacity alone.
CO2 recovery and a circular carbon economy
CO2 liquefaction can play an important role in creating more efficient carbon value chains. Instead of producing liquid CO2 exclusively from fossil sources, recovered carbon dioxide can potentially be reused in industrial, agricultural and food-related applications.
This makes CO2 recovery particularly interesting for facilities where a usable CO2 stream is already available.
As carbon capture, utilisation and storage continue to develop, efficient liquefaction technology can help bridge the gap between CO2 capture, transportation, storage and reuse.
FAQ’s
What is CO2 liquefaction?
CO2 liquefaction is the process of purifying, compressing and cooling gaseous carbon dioxide until it becomes liquid CO2. The liquid product can then be stored or transported.
Why is CO2 converted into liquid form?
Liquefied CO2 has a much higher density than gaseous CO2, making it easier and more efficient to store and transport.
Can CO2 from biogas production be liquefied?
Yes. CO2 separated during biogas upgrading can potentially be purified and liquefied. This can turn a by-product of biomethane production into a usable liquid CO2 stream.
