Simultaneous Absorption of SO₂ and CO₂ from Conventional and Partial Oxy-fuel Cement Plant Flue Gases

Abstract

In the context of Carbon Capture Utilisation or Storage (CCUS) applied to the cement industry to reduce its CO2 emissions, the current study was performed considering a CO2 capture technique likely to lower the energy costs of such process, namely the post-combustion CO2 capture by absorption-regeneration process applied to flue gases derived from an O2-enriched air combustion cement plant. Moreover, the present work is related to the effect of the presence of SO2 in the gas to treat on the CO2 absorption performances for several types of amine solvents (simple and blended solutions of MEA, MMEA, MDEA, AMP and PZ) considering a CO2 content in the flue gas between 20% and 60%. Absorption tests were performed in a laboratory gas-liquid contactor considering both CO2-loaded and unloaded solutions. It was shown that the presence of SO2 in the gas to treat lowers the CO2 absorption performances of the amine based solvents, contrarily to the SO2 absorption performances, staying quite high during the tests and confirming that this component is absorbed selectively relatively to CO2. Regarding the novel aspects deriving from the solvents screening, it was highlighted that PZ 10% leads to both high CO2 and SO2 absorption performances even in considerably CO2 loaded solution, while AMP 30% seems a good candidate to selectively absorb SO2 in the presence of CO2.