A review of degradation and emissions in post-combustion CO₂ capture pilot plants

Pilot plant testing of amine solvents for post-combustion CO₂ capture is an essential tool for fully understanding degradation behaviour and emission profiles under realistic process conditions. This review aims to summarise the lessons learned in different pilot campaigns, as well as to give recommendations how solvent stability and emissions can be monitored and assessed. A total of 18 different pilot plants and 29 individual campaigns were studied, of which the majority used ethanolamine and flue gas from coal-fired power plants.

The findings of the review are that solvent stability data from different pilot plants show significantly higher operation time in which the solvent is stable, when extensive flue gas pretreatment is implemented. It was also found that no single degradation compound seems to suffice for the assessment of the degradation of a solvent, even for the widely studied ethanolamine process. Monitoring of the total liquid-phase heat stable salt concentration, as well as gas phase ammonia concentration may, however, give an informative picture of the state and degradation of the solvent. There seems to be a lack of universally applied analytical methods, which makes it difficult to compare one campaign or location to another. The implementation of validated and documented analytical standards in this regard will facilitate production of reproducible, reliable and comparable data for future solvent stability assessment.