A new method of amine solvent recovery with acid addition for energy reduction in the CO₂ absorption process

Chemical absorption/stripping technologies using an amine-based solvent have a lot of advantages for capturing carbon dioxide in post-combustion capture system. However, the higher energy demand for the solvent recovery makes the technology difficult to retrofit to existing plants. To overcome this obstacle, an alternative stripping process using an organic acid was studied to decrease the solubility of carbon dioxide and save the energy demand, but further research is necessary to recover the amine solvent and an organic acid effectively. In this study, a new amine recovery method using an organic acid is proposed and the method suggests a two-step of reaction crystallization process to separate the amine and the acid. This study demonstrates that an amine solvent (monoethanolamine, MEA) and an organic acid (oxalic acid) could be recycled effectively by reaction crystallization experiment. MEA and oxalic acid recovery efficiencies were also obtained using the experimental data in this study. The percentages of MEA recovery and the acid losses were estimated through these data. In addition, the energy demands for two recovery processes were estimated.