CO2 stripping

CO2 stripping is a process removing carbon dioxide (CO2) from an aqueous solution by converting the carbon dioxide from liquid phase to gas phase. Together with our supplier RVT Process Equipment, we have extensive know-how and experience in the design and supply of components or complete columns for CO2 stripping.

In some industrial processes, it is important to remove the presence of carbon dioxide and to balance the pH level of the water. CO2 dissolved in water forms carbonic acid under certain conditions, which can lead to corrosion and deposits in pipelines and equipment. Removal of dissolved CO2 can also be essential to meet specific water quality requirements or to maintain the efficiency and safety of industrial processes. In aquaculture (e.g. land-based fish farming), CO2 stripping is used to remove excess CO2 from the water in which fish live.

How does CO2 stripping work?

CO2 stripping (CO2 degassing) is usually carried out in a packed bed column. The CO2-rich water enters the top of the column and flows downwards through the packed bed. Conversely, the stripping air enters the bottom of the column and travels upwards through the packed bed. The function the packed bed is to increase and optimise the liquid-gas contact area, with lowest possible pressure drop.

Removing carbon dioxide from aqueous solutions is part of a complex chemical system called the carbonate buffer system:

  • Carbon dioxide in gas phase ⇌ Carbon dioxide dissolved in water: CO2 (g) ⇌ CO2 (aq)
  • Carbon dioxide dissolved in water forms carbonic acid (H2CO3): CO2 (aq) + H2O ⇌ H2CO3 (the dominant form of CO2 in water below pH ~ 6)
  • Carbonic acid is converted to bicarbonate ions (HCO3-) and hydrogen ions: H2CO3 ⇌ H++ HCO3- (the predominant form of CO2 in water at pH ~ 8)
  • Bicarbonate ions are converted to carbonate ions (CO3-2): HCO3⇌ H+ + CO3-2 (the dominant form of CO2 in water above pH ~ 11)
  • Buffering: The bicarbonate ion acts as a weak alkaline and neutralises excess acid, while carbonic acid neutralises alkaline.

The carbonate buffer system is highly dependent on pH levels, operating temperature, pressure and other components (dissolved ions) in the water phase. It is important to note that only the dissolved carbon dioxide, CO2 (aq), can be removed by stripping. Therefore, monitoring and adjusting the pH value is crucial for the efficiency of carbon dioxide removal.

CO2 stripping is used in many industrial processes

CO2 degassing plays an important role in ensuring water quality, preventing corrosion and maintaining safety in various industrial processes. Here are a few examples of applications:

Seafood farming with Recirculting Aquaculture Systems (RAS)

In land-based seafood farming, Recirculating Aquaculture Systems (RAS) , water is circulated in a closed system. For fish and shellfish to thrive, the water they live and grow in must be of good quality. Fish absorb the oxygen in the water, leading to low levels of dissolved oxygen and high levels of dissolved carbon dioxide. Treating the water in a CO2 stripping column with ambient air, enriches the water with oxygen while reducing the CO2 concentration.

Industrial processes

In various industrial environments, carbon dioxide dissolved in water often leads to acidic water, i.e. water with a low pH value, which needs to be adjusted to minimise the risk of corrosion and deposits in equipment, pipelines, etc. As an example, in Combined Heat and Power plants, CO2 stripping is used to remove carbon dioxide from the feedwater to the boiler, preventing corrosion in the boiler and the steam system.

Project review and proposed solution

To deliver the optimal solution, it is important to go through in detail various factors that affect product choice, type of solution, investment objective, and other requirements at an early stage of the project.


AB Hansa Engineering AB
Alexander Bergman Droplet separation, Column internals, Spray nozzles & systems, Tank cleaning I look forward to providing product advice and solutions! Let's meet via a video call or a site visit. You can also phone or email us, of course.
LC Hansa Engineering AB
Linda Caporicci Column internals, Droplet separation, Spray nozzles & systems, Other products I look forward to providing product advice and solutions! Let's meet via a video call or a site visit. You can also phone or email us, of course.

A start-up meeting is important to find out about various factors that will affect choice of equipment and solution in order to achieve the most efficient and sustainable solution. We are happy to set up the start-up meeting as a web meeting or a site visit, depending on your preference. All details and information from the start-up meeting we will summarise and go through with you to make sure we agree on project scope and objective.

Next step, we present a proposed solution, focusing on function, lifespan, quality, choice of material, operating and maintenance costs, and environmental impact. Our goal is to deliver a sustainable solution that creates added value to your company,