CO2 Solubility in a Mixture Absorption System of 2-Amino-2-methyl-1-propanol with Glycol

Abstract

A mixture system of sterically hindered amine 2-amino-2-methyl-1-propanol (AMP) with glycol was developed as the working system to reduce energy consumption. The solubility of CO2 in the mixture solutions of AMP–diethylene glycol (DEG) and AMP–triethylene glycol (TEG) was determined by a fast measurement method. The results show that the physical absorption can be enhanced using TEG or DEG as a solvent. The heat of absorption of the CO2–AMP–glycol system ranges from 50 kJ/(mol CO2) to 62 kJ/(mol CO2) as the loading of CO2 (mol CO2/mol AMP) ranges from 0.2 to 0.8, which is much lower than that between monoethanolamine (MEA) and CO2. The absorption performance of the mixture system is sensitive both to temperature and pressure, which is different from the process with MEA as an absorbent. A reaction assumption of AMP with CO2 in DEG or TEG was suggested and a model for predicting the solubility of CO2 is developed accordingly. The prediction results show that the model can predict the absorption performance well. Comparing the MEA–TEG and AMP–TEG systems, we found that the AMP–TEG system would have much lower energy consumption in the CO2 absorption–regeneration process than the MEA–TEG absorption system.