Demineralized Water and CO2 Gas Relation
Producing demineralized water is a very costly and difficult process. The produced demineralized or ultra pure waters are in contact with air entering the tank from the venting line due to the change of water level in tanks where they are stored.
This water, which is purified from high levels of ions is a strong solvent and difficult to keep it as same quality as it is. When they come into contact with air, CO2 gas dissolves and ionizes in water. There are several ways to remove CO2 from water in advanced treatment processes. CO2 is removed with a degasser at acidic pH levels and with technologies such as anion exchange resin or reverse osmosis membranes at basic pH levels. After treatment CO2 gas dissolves again in demineralized water which is taken to storage tanks to be sent to the process, depending on factors such as surface contact area of storage tank, air-water interaction time, temperature, and carbon dioxide concentration in air. This situation may cause water conductivity to rise up to 1,5 µS/cm levels and pH parameter to fluctuate thus not achieving desired quality conditions of demineralized water.
Carbon dioxide slowly dissolves in water as carbonic acid (H2CO3) which is a form of weak acid, accompanied by the following reaction.
CO2 + H2O → H2CO3
Carbonic acid then forms hydronium (H3O+) and bicarbonate (HCO3–) ions in water with reversible equilibrium as shown in the reaction below.
H2CO3 + H2O → HCO3– + H3O+
With this chemical reaction it can be explained why acidic pH value is measured in a neutral pH valued water when it comes into contact with air.
On average, there is about 400 ppm of carbon dioxide in the air. If your demineralized or pure water tank is atmospheric then it is quite natural that CO2 will affect pH and conductivity values.
Cosorber CO2 Absorber Unit
Cosorber CO2 Absorber Unit allows you to maintain pH and conductivity values of your stored demineralized water. It can be mounted on storage tanks or can also be placed on ground by a pipeline if desired. Highly efficient and long lasting filtration media in absorber unit prevents CO2 gas from contact with water by holding it from the air entering to the tank. Since this filtration media is also equipped with a color indicator, media color changes when it reaches to maximum amount of CO2 it can absorb and filter cartridges are replaced. Air inlet and outlet of unit are safely provided with pressure and vacuum safety valves, differential pressure sensor. Dust particles that might come from outside are also captured with filters, thus preventing organic pollution that may occur in tank.
Sizing and design of Cosorber CO2 Absorber Unit is made by examining the operating data of storage tanks so that unnecessary costs are prevented with the units manufactured for each facility.
Suited Vessels for CO2 Absorber Unit
- Demineralized Water Storage Tanks
- Condensated Water Storage Tanks
- Desalineted Water Storage Tanks
- Caustic Storage Tanks
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