High-Throughput CO2 Solubility Measurement in Miscible and Liquid–Liquid Phase Separation Types of Amine Solvent Using Headspace Gas Chromatography

CO2 solubility is one of the key factors in evaluating not only the efficiency of the absorbent but also the energy consumption of the CO2 capture process from flue gas. In this study, a system namely headspace gas chromatography (HS-GC), which is a combination of gas chromatography (GC-3200, GL Sciences) and a headspace autosampler (Turbomatrix HS16, PerkinElmer), was developed to measure the CO2 solubility of amine solutions. The equilibrium time and calibration curve of this system were checked and compared with those of the literature data. The developed system showed high reproducibility with reference CO2 solubility data of benchmark amine solutions. Distinct from conventional measurement methods of CO2 solubility, high-throughput CO2 solubility measurement by HS-GC shows its advantages such as a small amount sample requirement, rapid achievement of equilibration time, automation of sample exchange, and high reproducibility, which is superior in the amine solvent screening phase. Moreover, this system can evaluate new types of CO2 capture solvents, including the phase separation solvent. By acquiring continuous data, the inflection point in the solubility curve indicated by phase separation was observed. The absorption heat estimated from those CO2 solubility curves measured by this system also agrees well with the experimental data.