Journal of CO2 Utilization (Jan 2024)
Enhancements of monoethanolamine CO2 absorption rate and degradation in the presence of nickel nanoparticles catalysts
Abstract
In the study of the catalytic effect of nickel nanoparticles (NiNPs) on amine-based CO2 capture systems, monoethanolamine (MEA) was subjected to a CO2 loading at greatly varying concentrations (3–30 wt%) at two temperatures (20 °C and 50 °C) for the first time in a lab study to the best of our knowledge. This study shows that NiNPs can enhance the rate of CO2 absorption into MEA and that its enhancement is greater at 20 °C than at 50 °C. Solutions were loaded with CO2 until full saturation and the mass gain was recorded. At 20 °C the overall enhancement ranged between 4.0–7.4% with the optimum (>7.0%) observed at concentrations of 5 wt% and 20 wt% of MEA with NiNPs. In addition, there were large reductions in the time that it takes to fully saturate the MEA with CO2, (up to a 42% reduction) and there were differences in peak loading (molCO2/molmea) between the NiNPs solution and the control (without NiNPs) (of up to 12.5% for the same time at 20 °C and 30 wt% of MEA with NiNPs). For the first time to the best of our knowledge, the degradation of MEA with and without NiNPs was studied; an oxidative degradation experiment (30 wt%, 0.4 molCO2/molmea, 7.5 mL/min CO2, 0.35 L/min air, 55 °C) based on typical absorber conditions and a thermal degradation experiment based on typical stripper conditions (30 wt%, 0.5 molCO2/molmea, 135 °C) were carried out. Gas chromatography-mass spectrometry was used to identify and quantify the major degradation compounds. It is found that NiNPs increase the rate of both oxidative and thermal degradation.
