Ethanolamine (MEA), a water-based solvent, has long been considered the “benchmark” solvent for post-combustion CO₂ capture. This is not because it is the best-performing solvent—it has relatively high energy requirements and is chemically unstable compared to newer alternatives.

Instead, MEA remains a reference point because there is an abundance of knowledge and public data about how it performs and how it degrades. Scientists have successfully identified more than 50 different by-products of MEA degradation and have accounted for all the nitrogen lost during this process. This means that the “mass and nitrogen balance” of MEA degradation is completely understood.

CESAR1: A Superior and Stable Alternative

While MEA is well studied, it is no longer the preferred choice for CO₂ capture. Newer solvents like CESAR1, a blend of piperazine (PZ) and 2-amino-2-methylpropan-1-ol (AMP), have replaced MEA because they are more stable and energy-efficient. CESAR1 was developed as part of the EU project CESAR (CO₂ Enhanced Separation and Recovery) between 2008 and 2011. This solvent has demonstrated excellent long-term stability and degrades much less than MEA, making it a more sustainable choice for industrial CO₂ capture.

The Need to Understand CESAR1’s Degradation

Although CESAR1 is highly stable, it is still important to understand how it breaks down when it does degrade. This is because degradation by-products can have negative impacts on the environment and plant operation. For example:

  • Some degradation compounds, like carcinogenic nitrosamines, could be harmful to the environment and public health.
  • Other compounds could interfere with plant operation by causing corrosion, accelerating further degradation, or creating unwanted issues like foaming.

To ensure the safe and smooth operation of CO₂ capture plants, researchers must fully identify and analyze all the possible degradation compounds CESAR1 can form. While it may not be necessary to track every single by-product continuously, it is crucial to identify all of them at least once. This will help pinpoint which compounds require regular monitoring to protect the environment and ensure efficient plant performance.

Understanding the degradation behavior of CESAR1 will provide the missing knowledge needed to operate CO₂ capture systems predictably and safely. This will not only ensure smooth industrial operation but also help minimize any environmental risks associated with solvent degradation.