The increase of CO₂ concentration in the atmosphere is in strong relation with the human-induced warming up due to industrial processes, transportation, etc. In order to reduce the CO₂ content, end of pipe post-combustion methods can be used in addition to other methods and techniques. The CO₂ capture by absorption in potassium carbonate⁻bicarbonate activated solutions remains a viable method. In this study, a mathematical model for a packed bed reactor has been developed and tested. The mathematical model is tested for an industrial reactor based on CO₂ absorption in Carsol solutions. The proposed model was validated by resolving for CO₂ and water content, carbonate⁻bicarbonate, concentrations etc. For each operational parameter the error was calculated. The error for CO₂ concentration is up to 4%. The height of the packed reactor is calculated as function of CO₂ concentration in the final gas phase. The validated model can also be used for absorbing other CO₂ streams taking into account the fact that its efficiency was proved in industrial scale. Future reactors used for CO₂ absorption should consist of two parts in order to use partially regenerated solutions in the first part, with significant energy savings in the operational costs.