Rate-based modelling and simulation of large-scale CO<inf>2</inf>capture using a piperazine-promoted aqueous ammonia solution

Abstract

Copyright © 2017, AIDIC Servizi S.r.l. Due to the fast reaction rate of piperazine (PZ) with CO 2 , it has the potential to act as a promoter in aqueous ammonia (NH 3 )-based CO 2 capture processes. A rigorous, rate-based model for the NH 3 -PZ-CO 2 -H2O system was developed using Aspen Plus®, and validated against experimental results. Absorption and desorption processes were simulated under real flue gas conditions to gain a practical understanding of the behaviour and characteristics of interactions between PZ-promoted NH 3 solution and CO 2 . Adding PZ significantly increased the CO 2 absorption rate in the NH 3 -based CO 2 capture process via a fast reaction between PZ carbamate and CO 2 . The temperature along the column was higher than in the absence of PZ, and additional NH 3 was released into the solution, which led to higher NH 3 loss. Adding PZ also reduced the stripping heat, resulting in a smaller energy requirement for solvent regeneration.