Two-Stage Flash for CO2 Regeneration: Dynamic Modeling and Pilot Plant Validation

Abstract

High operating cost and significant decrease in net power generation are major barriers to the implementation of post- combustion amine scrubbing for CO2 capture from coal-fired power plants. To improve efficiency and make the process more attractive economically, alternative process configurations and second generation solvents are being investigated. Dynamic modeling can be a useful tool in understanding the optimal operating conditions and control strategies for a proposed modified process; however, there are limited examples of dynamic model development for amine scrubbing. The Separations Research Program (SRP) at the University of Texas at Austin has completed a pilot plant campaign using a two-stage flash for CO2 regeneration as an alternative to a simple stripper, and piperazine solvent as an alternative to the baseline standard of monoethanolamine. This work develops a dynamic model for the alternative SRP configuration using first principles material and energy balances assuming an equilibrium stage process, and the model is validated with steady state SRP data. The model output was reasonably well matched to pilot plant measurements, with average temperature deviations of ≤1.7°C and average pressure errors of ≤ 3.4%.