Operating procedures and evaluation of a carbon capture pilot plant

Abstract: The rise in global emissions of carbon dioxide and the need for new technologies to combat climate change has prompted extensive research into carbon capture methods. This master thesis focuses on a novel carbon capture absorption technology, developed at Lund University, that utilizes the amine 2-amino-2-methyl-1-propanol (AMP) in the organic solvent dimethyl sulfoxide (DMSO) to capture CO2. A characteristic of this system is that when AMP in the AMP/DMSO system reacts with CO2, a carbamate that precipitates is produced, and a two-phase system is formed. Previous research has shown that during the regeneration of the absorbent the carbamate is dissolved, CO2 is separated and the regenerated AMP/DMSO solution is precipitate-free. Encouraged by promising results, a pilot plant to assess this technology on a larger scale has been built. The primary objectives of this master thesis were to try and achieve operational functionality of the pilot plant, develop sampling methods to measure emissions of AMP, DMSO and the nitrosamine N-dimethylnitrosamine (NDMA) and to investigate the regeneration conditions (e.g., temperature, time) for the AMP/DMSO system. During the course of this work, continuous operation of the pilot plant could not be achieved due to low temperatures that caused the AMP/DMSO system to freeze and due to issues with regeneration that left precipitate in the solution, which resulted in clogging. Despite difficulties caused by persistent clogging, noteworthy findings were obtained. Contrary to previous research, it was discovered that precipitate remained present in the AMP/DMSO solution even after undergoing regeneration. Additionally, the results in this master thesis showed that the structure of the precipitate might be influenced by the presence of water in the solution. Regeneration experiments conducted at the regeneration conditions employed at the pilot plant, 80°C and – 10 mbarg, indicated that the conditions should be sufficient for regenerating the AMP/DMSO system to the equilibrium curve of the solubility of CO2 in AMP/DMSO. Emissions of AMP, DMSO and NDMA demonstrated lower levels than the initial estimation based on the temperature and vapor pressure of the pure components. However, these results are not representative for continuous operation of the pilot plant since only intermittent operation could be achieved due to the clogging issues. Regarding the future for the pilot plant project, the persistence of precipitate in the solution after the regeneration step and the potential impact of water on the precipitates structure are subjects of interest for further research. Additionally, addressing the clogging challenges at the pilot plant remain crucial for future research.