Parametric study of the reactive absorption of CO2 for soda ash production

The design of carbon-negative processes replacing traditional energy-intensive processes is desirable to achieve the UN sustainability goals. The CODA project aims to develop a sustainable process to produce soda ash by capturing airborne CO2 using NaOH followed by a crystallization sequence. This work aimed to analyze the influence of three process variables, namely the Na2CO3 concentration, the temperature and air humidity in the absorber. The CO2 capture rate, the energy consumption and the water loss in the absorber were considered as process performance variables. High Na2CO3 concentrations result in small capture rates in the absorber, which is directly related with larger absorbers and higher energy consumption for pumping. Absorption is favored at low temperatures because the Na2CO3 saturation concentration is smaller and water loss is reduced. The assessment of two downstream schemes in terms of energy led to the identification of opportunities for further process optimization.