2-Amino-2-methyl-1-propanol based non-aqueous absorbent for energy-efficient and non-corrosive carbon dioxide capture

Abstract

The large-scale deployment of carbon dioxide (CO2) capture using aqueous amines is mainly limited by its intensive energy penalty. In this regard, non-aqueous amine solutions have high energy-saving potential because organics have lower heat capacity and vaporization enthalpy than water. In this study, 2-amino-2-methyl-1-propanol (AMP) coupled with activators in an inert organic solvent (N-methyl pyrrolidone, NMP) is proposed for energy-efficient CO2 capture. The relationships between activator properties and CO2 capture performance, such as absorption capacity, regeneration efficiency, and corrosion behavior, were investigated. The results showed that the non-aqueous AMP-AEEA (2-(2-aminoethylamino)ethanol)-NMP solution not only possessed high CO2 capacity (1.65 mol·kg−1 solution) but also retained nearly 90% of its initial CO2 capacity after the 4th cycle of regeneration. Moreover, it presented a non-corrosive behavior after saturated absorption, clearly showing its superiority over the benchmark monoethanolamine (MEA) solution. The 13C nuclear magnetic resonance (NMR) spectra provided evidence of CO2 reacting with AMP-AEEA in NMP to form carbamates, which could be easily regenerated under thermal desorption. The specific solvent loss was 0.14 kg⋅kg−1 CO2 and the total heat duty of AMP-AEEA-NMP solution was only about half that of the MEA solution, which can be attributed to the absence of water and properties of the inert organic solvent. With the perfect CO2 capture performance, non-corrosive behavior, and significant reduction of energy consumption, the novel solution is a promising candidate for CO2 capture.