Emission characteristics of ethanolamine and ammonia in CO2 capture process by chemical absorption based on ethanolamine solution

Abstract

BACKGROUND

The massive emission of greenhouse gases represented by CO₂ has led to many environmental and climate problems. Chemical absorption after combustion has become an effective method for CO₂ capture. Meanwhile, this method also leads to potential emission of pollutants, consisting mainly of ethanolamine (MEA) and ammonia (NH₃). However, few studies focus on the emission characteristics of pollutants in chemical absorption systems and the factors influencing the emissions.

RESULTS

In this experiment, MEA and NH₃ emissions during the CO₂ capture process by the chemical absorption method under different conditions, such as flue gas and absorbent solution temperature, liquid-to-gas ratio, CO₂ concentration in the flue gas, and absorbent CO₂ loading, were investigated. The results indicate that the MEA and NH₃ are released during the CO₂ capture process, and the amount of release varies with many parameters. Under typical conditions, the emissions of MEA and NH₃ were stabilized at 85.8 and 21.5 mg Nm⁻³, respectively. The emissions of MEA and NH₃ increased steadily with the temperature of the flue gas and increasing absorbent solution. Higher liquid-to-gas ratio led to more MEA and NH₃ emissions, and higher absorbent CO₂ loading could inhibit the MEA and NH₃ emissions. Calculation of the maximum reduction rate also showed that CO₂ loading has the greatest impact on pollutant emissions, and optimizing it reduces pollutant emissions by at least 40%.

CONCLUSION

It was found that pollution emissions can be controlled by optimizing operating parameters, which can provide a reference for reducing pollutant emissions in the industry. © 2025 Society of Chemical Industry (SCI).