Filter Units for the removal of Carbon Dioxide

Carbon dioxide removal units are used on tank breathing systems where ingress of atmospheric air can alter the chemical quality of the stored medium. A typical application is condensate and demineralized water tanks in power generation plants, where CO₂ from ambient air dissolves into the water and can increase conductivity, shift pH, and add load to the water/steam cycle.

The unit may be installed directly on the tank breather through a flanged connection or mounted at grade with ducting to the tank’s inlet and outlet breathing lines. Location is selected based on maintenance access, available structural support, duct pressure loss, and the need for weather protection.

These assemblies include replaceable CO₂ adsorption cartridges together with pre-filters and after-filters to limit particulate carryover before and after the chemical adsorption stage. The design should also incorporate a pressure/vacuum relief valve so that airflow can bypass the unit if the filters become blocked, preventing the tank from being exposed to unacceptable differential pressure.

Selection should be based on maximum breathing flow during filling or emptying, inlet CO₂ concentration, allowable pressure drop, required contact time with the adsorbent media, and compatibility with the tank service. Maintenance typically includes differential pressure monitoring, cartridge replacement when adsorption capacity is exhausted, and periodic inspection of the pressure/vacuum relief valve.