Screening Amino Acid Salts as Rate Promoters in Potassium Carbonate Solvent for Carbon Dioxide Absorption

Guoping Hu, Kathryn H. Smith, Yue Wu, Sandra E. Kentish, Geoff W. Stevens

Research output: Contribution to journalArticle

21 Citations (Scopus)


Potassium carbonate shows promise as a solvent for carbon capture due to its low cost and low environmental impact. However, improving the absorption kinetics of potassium carbonate solvent is crucial for reducing the capital cost of absorption equipment required to build the carbon dioxide capture plant. In this study, a series of amino acid salts were screened as reactants with carbon dioxide using the stopped flow technique. The amino acids investigated in this study were 2-piperazinecarboxylic acid, asparagine, aspartic acid, glycine, leucine, lysine, proline, sarcosine, serine, and valine. Furthermore, proline, sarcosine, glycine, leucine, and lysine were tested as rate promoters in potassium carbonate solvent for carbon dioxide absorption using a wetted wall column. Results showed that the amino group in the anions of the amino acid salt is the major species reacting with carbon dioxide. Therefore, the promoting effect of amino acid salts is sensitive to changes in pH values due to changes in species distribution of the amino acid salts with pH. Sarcosine and proline are the most effective promoters among the amino acid salts tested in this study with comparable promoting performance at higher pH values (≥12.5) but with sarcosine more effective at lower pH values (<12.5). Compared to 0.5 M monoethanolamine (MEA) as a promoter, sarcosine and proline showed faster rate promotion effects for carbon dioxide absorption into 30 wt % potassium carbonate solvents at high pH (>12.0), while the promoting performance of MEA was comparable with that of proline and slightly poorer than that of sarcosine at low pH (<12.0) conditions.

Original languageEnglish
Pages (from-to)4280-4286
Number of pages7
JournalEnergy and Fuels
Issue number4
Publication statusPublished - 20 Apr 2017
Externally publishedYes

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