Monitoring of the blend 1-methylpiperazine/piperazine/water for post-combustion CO2 capture. Part 1: Identification and quantification of degradation products

Abstract

Post-combustion CO2 capture process using amine solvents is limited by the high energy penalty and the irreversible degradation of amines. The present work aimed at studying the degradation of the innovative blend 1-methylpiperazine/piperazine (1MPZ/PZ: 30/10%wt.) in a lab-scale pilot plant, LEMEDES-CO2, with conditions representative of post-combustion CO2 capture for power generation. Degradation of the solvent was realized twice during 800 and 955 h. Addition of acidic impurities (H2SO3 and HNO3) in the second campaign was performed in order to study their impact on the solvents degradation. CO2 loadings were determined and showed an average value of 0.28 for the lean solvent and 0.63 for the rich solvent. In order to identify and quantify degradation products, complementary analytical strategies were developed involving LC–MS, ionic chromatography and GC–MS. In order to monitor the gaseous effluents, a sampling on solid sorbents (Tenax® TA) was performed followed by thermodesorption and GC–MS analysis. This study permitted the identification of 23 degradation products in the liquid phase of the solvent, and 16 emitted with the treated flue gas. Among them were found piperazine derivatives, alkylpyrazines and organic acids. Quantification was performed on both liquid and gaseous phases on 10 selected compounds.