Absorption rates and CO2 solubility in new piperazine blends

Le Li, Han Li, Omkar Namjoshi, Yang Du, Gary T. Rochelle

Research output: Contribution to journalConference articlepeer-review


The absorption rate and CO2 solubility of four new blends using concentrated piperazine (PZ) were measured. The blends are 6 m PZ/2 m hexamethylenediamine (HMDA), 6 m PZ/2 m diaminobutane (DAB), 6 m PZ/2 m bis(aminoethyl)ether (BAE), and 5 m PZ/2 m N-2(aminoethy)lpiperazine (AEP). The liquid film mass transfer coefficient (kg') of the blends was measured at 20 100 °C using a wetted wall column (WWC). P CO2* was measured at 20 100 °C using the WWC, and at 100 160 °C using a total pressure apparatus. A semi-empirical VLE model was regressed for each blend using measured PCO2*, and the models show good agreement with experimental data. The process performance of the new blends is compared to 5 m PZ/2.3 m AMP, 2 m PZ/4 m AMP, 8 m PZ, and 7 m MEA. The high pKa of primary diamines contributes to high lean and rich loading and low solvent capacity for 6 m PZ/2 m HMDA, 6 m PZ/2 m DAB, 6 m PZ/2 m BAE. The ΔHabs of PZ/AEP and PZ/AMP is competitive with 7 m MEA. PZ/BAE and PZ/HMDA have ΔHabs higher than 8 m PZ but lower than 7 m MEA. The energy performance of the solvent depends on CO2 VLE and thermal stability. 6 m PZ/2 m HMDA, 6 m PZ/2 m AEP, and 5 m PZ/2 m BAE show good energy performance and are competitive with 8 m PZ. At 40 °C the absorption rate of 5 m PZ/2 m AEP is about the same as 8 m PZ; 6 m PZ/2 m DAB and 6 m PZ/2 m BAE have 10% lower rates than 8 m PZ.

Original languageEnglish (US)
Pages (from-to)370-385
Number of pages16
JournalEnergy Procedia
StatePublished - 2013
Externally publishedYes
Event11th International Conference on Greenhouse Gas Control Technologies, GHGT 2012 - Kyoto, Japan
Duration: Nov 18 2012Nov 22 2012


  • Absorption rate
  • Capacity
  • Energy performance
  • Piperazine
  • Solvent blends

ASJC Scopus subject areas

  • Energy(all)


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