Oxidative degradation of aqueous PZ solution and AMP/PZ blends for post-combustion carbon dioxide capture

Aqueous blends of 2-amino-2-methyl-1-propanol (AMP) and piperazine (PZ) appear to be commercially attractive solvents for post-combustion CO2 capture by absorption/stripping. An experimental study on the oxidative degradation of aqueous PZ solutions and AMP/PZ blends was carried out. The oxidative degradation experiments were performed in a 200 mL glass batch reactor with an oxygen partial pressure of 250 kPa, and at the temperatures of 80-120 °C. The amine loss was determined by cation ion chromatography (IC) while the degradation compounds were identified and quantified by gas chromatography-mass spectrometry (GC-MS), cation IC and anion IC. Possible chemical pathways of PZ oxidative degradation are proposed to account for the observed degradation products. As compared to oxidative degradation of single AMP and PZ solvents, no new product was observed in partially degraded AMP/PZ blends. However, PZ degraded faster in the blends than it degraded individually at identical degradation conditions.