The effect of biomass ashes and potassium salts on MEA degradation for BECCS

•The impact of biomass and coal ashes on the degradation of 30 wt% aqueous monoethanolamine (MEA) has been studied.•Thermal and oxidative degradation experiments were carried out and quantified using 1H NMR and GC–MS.•N-(2-hydroxyethyl)imidazole-N-oxide (HEINO) which had been previously miss-assigned is a major degradation component.•HEINO is likely to act as an oxygen carrier responsible for oxidative degradation under stripper conditions.•CCS from white wood biomass combustion may observe less amine degradation than coal or olive biomass plant combustion.