Modeling of pilot stripper results for CO2 capture by aqueous piperazine

• Published in: International journal of greenhouse gas control Vol. 12; pp. 280 - 287
• Main Authors: Van Wagener, David H., Rochelle, Gary T., Chen, Eric
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-01-2013
• Subjects: Amine scrubbing; Carbon capture; Carbon dioxide; Modeling; Piperazine; Stripper; USA, Texas, Austin; Amine scrubbing; Stripper; Piperazine; Modeling; Carbon capture; Carbon dioxide
• DOI: 10.1016/j.ijggc.2012.11.018
• EISSN: 1878-0148
• ISSN: 1750-5836

► Piperazine solvent was successfully regenerated with a 2-stage flash. ► The pilot required 45kJ/mol CO2 work because of undersized cross exchanger. ► A rigorous model in AspenPlus was validated with the pilot plant data. ► With an optimal design, the model predicts equivalent work of 34kJ/mol CO2.
Two campaigns were run with concentrated PZ at the University of Texas at Austin pilot plant for CO2 capture. One campaign used a simple stripper, and the next used an innovative 2-stage flash skid. Both campaigns were analyzed for their approach to equilibrium in the respective heater process units. The total pressure measurements from nearly all runs from both campaigns matched the total pressure prediction by the equilibrium model within 5%. The energy efficiency with the 2-stage flash was low due to heat loss and a high approach temperature in the heat exchanger. The lowest heat duties for the simple stripper and 2-stage flash were 128 and 170kJ/mol CO2, respectively. The 2-stage flash campaign demonstrated significantly higher hot side temperature approaches on the main heat exchanger, which increased the sensible heat requirement. A sensitivity analysis revealed that the heat duty of a representative case from the campaign could be reduced to 143kJ/mol CO2 with a hot side approach of 10°C.