Oxidative degradation of a novel AMP/AEP blend designed for CO₂ capture based on partial oxy-combustion technology

Solvent degradation and volatile compound emissions are two of the major concerns about the deployment of carbon capture technologies based on chemical absorption. In this context, partial oxy-combustion might reduce the solvent degradation due to the use of a higher CO2 concentrated flue gas. This work evaluates the oxidative degradation of a novel AMP/AEP blend, namely POS #1, under partial oxy-combustion conditions. The effects of temperature and flue gas composition were evaluated in terms of solvent loss, degradation rates, NH3 emissions and degradation products. The experiments were set at temperatures up to 70 ˚C and two levels of O2 concentration – 3%v/v and 6%v/v. The CO2 concentration of the flue gas ranged between 15%v/v and 60%v/v CO2.
The novel solvent POS#1 showed high resistance to degrade and resulted in lower degradation rates than MEA in all the operating conditions evaluated in this work. The maximum degradation of AEP and AMP was 24% and 19%, respectively. MEA degraded almost double under the same conditions. Temperature and O2 concentration enhanced the oxidative degradation of POS #1. However, the use of higher CO2 concentration in the flue gas led to lower degradation rates of AEP and AMP and hence oxidative degradation was partially inhibited under partial oxy-combustion conditions. The presence of higher CO2 content in the flue gas decreased the NH3 production and a 70% reduction of its emissions was achieved as the CO2 concentration shifted from 15%v/v to 60%v/v. Other major degradation compounds such as formate and 2,4-lutidine were also decreased. New degradation products were not identified so that the suggested degradation pathways proposed in the literature were not influenced by the presence of higher CO2 concentrations.