Reclaiming of Amine CO2 Solvent Using Extraction of Heat Stable Salts in Liquid-Liquid Membrane Contactor

Abstract

Amine CO2 solvents undergo oxidative degradation with the formation of heat stable salts (HSS). These HSS reduce the sorption capacity of amines and lead to intense corrosion of the equipment. In our work, we propose a membrane-supported liquid-liquid extraction of the HSS from alkanolamines. For this purpose, a hollow fiber membrane contactor was used for the first time. A lab-scale extraction system on the basis of a hollow-fiber liquid-liquid membrane contactor with hollow fiber ultrafiltration polyvinylidenefluoride and polysulfone membranes has been studied. The extraction of the HSS-ions from a 30 wt.% solution of monoethanolamine was carried out using a 0.25–1 M solution of OH-modified methyltrioctylammonium chloride in 1-octanol as an extractant. It has been shown that >90% of HSS ions can be extracted from the alkanolamine solvent within 8 h after extraction. The results obtained confirm the possibility of using membrane extraction with a liquid-liquid membrane contactor for the reclaiming of amine CO2 solvents to increase the general efficiency of carbon dioxide capture.

Handling heat‐stable salts in post‐combustion CO2 capture: A detailed survey

“…This methodology is known as solvent extraction or liquid‐liquid extraction. It allows the extraction of HSSs even at very low concentrations and they are achieved with reduced energy utilization 151 . This is an improvement to the excessive energy demand and coevaporation problems associated with distillation, as well as the specificity for only the separation of ionic species associated with ion exchange technique.…”

“…It allows the extraction of HSSs even at very low concentrations and they are achieved with reduced energy utilization. 151 This is an improvement to the excessive energy demand and coevaporation problems associated with distillation, as well as the specificity for only the separation of ionic species associated with ion exchange technique. The principle of solvent extraction has been popularized in several industrial applications like wastewater treatment, biochemistry and biotechnology, biofuel treatment, pharmaceutical purification, and environment remediation.…”