Analysis of flexible operation of CO2 capture plants: Predicting solvent emissions from conventional and advanced amine systems

Abstract

In our previous work, we reported results on solvent management, emissions, and dynamic behavior from an 18-month testing campaign with monoethanolamine (MEA) at the PCC pilot plant at Niederaussem. In this study, we extended our work to include the CESAR1 solvent, a blend of 2-amino-2-methyl-1-propanol (AMP) and piperazine (PZ) in water, as part of our efforts in the ALING-CCUS project to evaluate if CESAR1 could be established as a new benchmark solvent for post-combustion capture. From our long-term (>12,275 h) testing experience, CESAR1 has shown a substantial promise in terms of lower specific solvent regeneration energy demand and stability to degradation in comparison with MEA. However, during a comprehensive series of parametric tests with the CESAR1 solvent, it was observed that amine emissions are significantly higher, especially under transient operation (AMP: 30 – 100 mg/m3 (STP); PZ: 2 – 30 mg/m3 (STP); MEA: <8 mg/m3 (STP)). This work presents step response functions for predicting the time delay and gain in emissions for each parametric/dynamic test performed. Some dynamic tests show a fast response and high emission values and, therefore, can be used to reduce emissions during flexible plant operation. These control actions are mainly the lean solvent and/or water wash temperature increase and are similar to those observed in the MEA campaign. Our testing campaign helps in advancing the fundamental understanding of emissions, establishing optimal mitigation strategies, and providing important insights for future development of models regarding solvent emissions and degradation.