An account of solvent regeneration energy for amine-based CO2 capture technology: A focus on selected ring-structured amines and parametric evaluation

Abstract

Amine-based CO2 absorption technology is a leading contender for large-scale commercial carbon capture. While the technology is mature and its large-scale deployment is already proven, new approaches are still needed to fully unlock its potential and reduce the cost. The primary factor driving the cost of amine-based CO2 removal is solvent regeneration energy. Beyond new solvents, process operating conditions also play a crucial role in reducing regeneration energy and improving process performance. This study provides a broader view and understanding of amine-based CO2 capture technology along with solvent CO2 capture characteristics and regeneration approaches. To provide a perspective and understanding of regeneration energy this study explores six ring-structured amines such as piperazine, 1-methylpiperazine, 2-methylpiperazine, 2-piperidineethanol, 1-(2-hydroxyethyl)pyrrolidine and morpholine as the example cases. Optimized electrolyte NRTL model is used to determine the vapor liquid equilibrium behavior of the aqueous amine solutions for CO2 capture. A robust short-cut method is used to determine the solvent regeneration energy. Effects of various parameters such as CO2 partial pressure, absorption temperature, desorption temperature, amine concentration, stripper total pressure and CO2 recovery are investigated. A global sensitivity analysis is performed to identify the most influential parameters. The applications of these solvents are investigated for various industrial CO2 emissions, and the results ae highly competitive when compared to MEA. Results highlight that absorber and stripper temperature followed by stripper total pressure, absorption CO2 partial pressure and amine mass are influential parameters. Higher CO2 recoveries are possible with smaller energy penalties.