Pilot study of a novel electrochemical approach for NOx removal from flue gas

This study utilizes a Power-to-X (PtX) mini-pilot to remove NO x impurities from synthesized cement flue gas. The system consists of a combined alkaline scrubber and oxidative electrochemical scrubber. We demonstrate that the oxidative scrubber effectively oxidized NO, while the alkaline scrubber provided additional NO removal and partial NO 2 absorption. The integrated system achieved over 99% NO removal during transient operation, and a 93.95% reduction during steady state operation. The results highlight that an overall ∼79% of NO x removal was achieved. Additionally, as the alkaline solvent reached saturation, CO 2 capture by the system became negligible, proving its suitability as a pretreatment step in carbon capture, utilization, and storage (CCUS) processes. Liquid analysis of the alkaline solvent revealed inorganic speciation, including early carbonate/bicarbonate and nitrate formation, followed by a shift toward bicarbonate-rich chemistry. These findings highlight that an electrochemical scrubbing pretreatment system upstream of CCUS plants can successfully reduce NO x concentrations. This could result in mitigation of amine solvent degradation and enhanced process efficiency and longevity, underscoring the system's potential for scalable PtX and CCUS applications.