Experimental investigation on post-combustion CO2 capture for [Bpy][NO3] and MEA aqueous blends with lower regeneration energy

Abstract

CO2 capture is an important technology to achieve carbon emission reduction. The key is reducing the energy consumption of the CO2 capture process. Ionic liquids (ILs) blended with organic amines can be used as an efficient CO2 absorbent allowing for low regeneration energy consumption. This work proposes the use of N-butylpyridinium nitrate ([Bpy][NO3]) in combination with organic solvents for CO2 capture. The effects of ILs concentration, reboiler load and flue gas concentration on regeneration energy consumption were studied on a continuous pilot unit for absorption-desorption process. The results showed that the CO2 absorption capacity of 30 wt% MEA + 10 wt% [Bpy][NO3] was 0.1308 g CO2/g solvent, higher than monoethanolamine/water, and the CO2 absorption capacity remained at 74.3% after the five cycles. At 40 °C, the viscosity of IL-amine blending solvents before and after absorption was 2.01 and 3.534 mPa·s, respectively, significantly lower than that of the conventional non-aqueous phase absorbent. The continuous absorption-desorption results showed that the capture rate of IL blending reached more than 95%. The regeneration energy consumption is 34.2% lower than the 30 wt% MEA.