Improvement of Lipophilic-Amine-based Thermomorphic Biphasic Solvent for Energy-Efficient Carbon Capture

A series of novel lipophilic amine solvents have been studied for improving the energy efficiency of post-combustion carbon capture (PCC). More than thirty lipophilic amines with varying molecular structures, for instance primary amine Cycloheptylamine (CHpA), secondary amine Dibutylamine (DBA) and tertiary amine N-Ethylpiperidine (EPD), with respect to their phase separation temperatures, loading capacities, reaction kinetics and regenerabilities have been investigated by screening tests at temperatures between 25-90 °C. The further solvent selection was assessed by absorption at 30-40 °C with 50-500 mbar CO2 partial pressure and desorption at 75-85 °C with intensified regeneration measures in absence of steam stripping. Compared to monoethanolamine (MEA), selected lipophilic amines have performed excellently in CO2 loading, solvent regenerability and chemical stability. The low temperature (≈80 °C) required for desorption also permits the use of waste heat for reducing the operating cost.