Characteristics of carbon dioxide desorption from MEA-based organic solvent absorbents

The fundamental characteristics of CO2 desorption from absorbents were assessed to highlight the importance of CO2 desorption in a CO2 absorption field. Four monoethanolamine (MEA)-based absorbents were tested for their absorption and desorption performances, including MEA/water, MEA/ethanol, and two kinds of MEA/ethanol/water. MEA/ethanol exhibited a higher absorption rate, higher regeneration fraction, and lower desorption temperature for CO2 desorption as compared to others. Compared with MEA/water, MEA/ethanol had a 20 degrees C lower desorption temperature, 41.72 % higher average desorption rate (in the first 20 min) and 5.52 percentage points higher regeneration fraction. MEA/ethanol/water showed very poor desorption performance, with regeneration fractions between 64-82 %. The desorption energy requirement of MEA/ethanol is significantly lower than that of MEA/water with all absorbent CO2 loading ratios. At the CO2 loading of 0.07 mol CO2/mol MEA, the desorption energy requirement of MEA/ethanol was 80 % less than that of MEA/water. For all absorbents, the desorption process took 3-5 times longer than that required for the absorption equilibrium to be reached, and absorbent CO2 loading had a significant influence on CO2 absorption with a higher absorption rate at lower CO2 loading. The results also indicated that adding organic solvents such as ethanol could reduce the desorption energy consumption and desorption temperature, which is conducive to absorption and also important for selecting the right absorbent.

Automated summary

The study evaluated the importance of CO2 desorption in the CO2 absorption field and tested four MEA-based absorbents for their absorption and desorption performances. MEA/ethanol exhibited superior properties compared to other absorbents, while MEA/ethanol/water showed poor desorption performance.