Heat duty, heat of absorption, sensible heat and heat of vaporization of 2–Amino–2–Methyl–1–Propanol (AMP), Piperazine (PZ) and Monoethanolamine (MEA) tri–solvent blend for carbon dioxide (CO2) capture

Abstract

Chemical absorption using reactive amines for carbon dioxide (CO2) capture is characterized by absorption heat, heat of desorption and heat duty for regeneration (Qreg, kJ/mol CO2). This study experimentally investigated the heat duty of tri–solvent blends containing AMP–PZ–MEA and the individual contribution of desorption heat, sensible heat and heat of vaporization to heat duty. The experimental conditions for absorption were 15 v/v% CO2 at 40 °C and atmospheric pressure while desorption was carried out 90 °C for loaded amine also at atmospheric pressure. The heat of desorption was experimentally determined using the specific heat capacity (kJ/kg °C) difference between the CO2 free and CO2 saturated amine solutions at the stated absorption conditions. Results showed that the heat duty of all the tri–solvent blends was significantly lower than that of the standard 5 kmol/m3 MEA. Interestingly, the AMP–PZ–MEA tri–solvent blends exhibited only slightly lower heats of absorption when compared to MEA; however, they also showed significantly lower sensible heat and slightly lower heat of vaporization. Consequently, the tri–solvent blends exhibited significantly lower heat duties than the standard 5 kmol/m3 MEA. In addition, a model analogous to a power law kinetic model was developed and used to predict the specific heat capacity of the AMP–PZ–MEA tri–solvent blends. The model accurately predicted the experimental results with an AAD of 0.59%. The overall results highlight the potential of using AMP–PZ–MEA blends for CO2 capture.