In Situ Raman Methodology for Online Analysis of CO₂ and H₂O Loadings in a Water-Lean Solvent for CO₂ Capture

Abstract

Carbon capture represents a key pathway to meeting climate change mitigation goals. Powerful next-generation solvent-based capture processes are under development by many researchers, but optimization and testing would be significantly aided by integrating in situ monitoring capability. Further, real-time water analysis in water-lean solvents offers the potential to maintain their water balance in operation. To explore data acquisition techniques in depth for this purpose, Raman spectra of CO 2, H 2 O, and a single-component water-lean solvent, N-(2-ethoxyethyl)-3-morpholinopropan-1-amine (2-EEMPA) were collected at different CO 2 and H 2 O concentrations using an in situ Raman cell. The quantification of CO 2 and H 2 O loadings in 2-EEMPA was done by principal component regression and partial least squares methods with analysis of uncertainties. We conclude with discussions on how this simultaneous online analysis method to quantify CO 2 and H 2 O loadings can be an important tool to enable the optimal efficiency of water-lean CO 2 solvents while also maintaining the critical water balance under operating conditions relevant to post-combustion CO 2 capture.