Promoted sodium carbonate solvent for CO2 capture by amino acids using membrane contactor technology

Details

Supervisors

Luis Alconero, Patricia

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil en chimie et science des matériaux

Abstract

In this master thesis, the different issues linked to CO2 emission into the atmosphere are presented along with the solutions to remove it. As the most promising technology for CO2 capture, post-combustion capture technologies are detailed with a focus on membrane contactor technology. Carbonate solutions as liquid absorbent for this technology is highlighted along with different promoters. The optimisation of the CO2 absorption process for promoted sodium carbonate solvent by amino acids (arginine and sarcosine) using hollow fibre membrane contactor technology is presented in this study. This was done experimentally. First, experiments with different arginine concentration (0.1M, 0.3M, 0.5M, 0.7M) for 400mL of 0.5M sodium carbonate aqueous solution were performed. Experiments with liquid temperature change (20°C, 25°C, 30°C, 35°C) on the 400mL promoted 0.5M sodium carbonate by 0.5M arginine aqueous solution were also performed. From these experiments, optimal concentration of arginine and optimal liquid temperature were determined. Arginine shows good promoting performance on sodium carbonate solution and optimal concentration of arginine was determined at 0.5M. Impact of the liquid temperature on absorption was not significant. Then, experiments with sarcosine concentration variation (0.1M, 0.3M, 0.5M, 0.7M) for 400mL of 0.5M sodium carbonate aqueous solutions were performed at least twice. Optimal concentration of sarcosine was determined. Sarcosine turns out to be a good promoter at low concentration. High concentration of sarcosine leads to a decrease of solubility which affects the absorption performance. Optimal concentration was 0.3M. Comparison of these results was performed to determine which amino acid was the best in terms of absorption performance but also for the membrane contactor. Simplified economical assessment was performed to compare them for the similar performance. Turns out that arginine was the best promoters in terms of absorption and economically. Finally, effect of sodium bicarbonate on the process was discussed by addition of different concentrations of sodium bicarbonate (0.1M, 0.3M, 0.5M, 0.8M, 1M) in 400mL promoted 0.5M sodium bicarbonate by 0.5M arginine aqueous solution. These experiments were achieved at least twice and results allow to determine whether sodium bicarbonate in the solution had a negative impact or not. Bicarbonate altered the absorption and the promoting effect of arginine. Precipitation at high concentration can affect the membrane contactor.