Regeneration with Rich Bypass of Aqueous Piperazine and Monoethanolamine for CO2 Capture

Amine scrubbing is the most mature CO2 capture technology for fossil fuel power plants, but the energy use for CO2 regeneration and compression will be 20 to 25% of the power plant output. The objective of this work is to develop alternative stripper configurations that reduce the energy use of CO2 capture. The advanced stripper configurations were modeled and optimized using Aspen Plus. Total equivalent work was used as an indicator of overall energy performance accounting for reboiler duty, compression work, and pump work. The rich exchanger bypass recovers stripping steam heat by using an exchanger. To get better energy performance, this strategy was applied to advanced configurations including a reboiler-based stripper, an interheated stripper, and a flash stripper. Both 9 m monoethanolamine (MEA) and 8 m piperazine (PZ) were investigated. The best energy performance was obtained from the stripper with a warm rich bypass and a rich exchanger bypass, which provides 10% less equivalent work for PZ and 6% less for MEA compared to the simple stripper. A flash stripper with a warm rich bypass and rich exchanger bypass uses 9% less energy with PZ and 5% less with MEA With the warm rich bypass and rich exchanger bypass, MEA can provide 8% less equivalent work at 135 degrees C with acceptable thermal degradation.