Available data and knowledge gaps of the CESAR1 solvent system

Abstract

Amine-based chemical absorption stands out as the leading technology for post-combustion CO₂-capture. A blend of 3 M 2-amino-2-methyl-1-propanol (AMP) and 1.5 M piperazine (PZ), also known as CESAR1, has proven to outperform the current benchmark ethanolamine (MEA), exhibiting better energy performance and lower degradation rates. This review aims to gather all the experimental laboratory and pilot available data for CESAR1 and its constituent components. Experimental gaps to develop reliable process models are detected and future experiments are proposed. An overview of the knowledge related to amine and degradation compound emissions and environmental impacts of CESAR1, together with hands-on experience in operating the solvent, is presented in this review.

The main findings of the review are that sufficient physical properties, N₂O-solubility, and speciation data for the CESAR1 solvent are not available in the open literature, even though necessary for the development of reliable process models. A review of the degradation compounds for AMP, PZ and AMP/PZ blends outlines that the nitrogen balance for AMP and PZ is not closed, meaning that there still are compounds that need identification and quantification in the degraded solvent. Given the higher volatility of AMP compared to MEA, a better understanding of the formation and behaviour of aerosol and gas phase emissions is required. A review of pilot plant campaigns for AMP/PZ blends shows that CESAR1 performs better in terms of energy compared to MEA and degrades less. There is, however, the need for high-quality pilot campaigns where all data needed for process model validation is provided for the scientific community. Finally, amine emission mitigation strategies and data on the environmental impact and toxicity of AMP and PZ are presented and discussed.