Principles and practical measurement and control strategies for achieving ultrahigh CO2 capture rates in amine post-combustion capture plants

Amine post-combustion capture (PCC) plants must maximise CO2 capture rates to support net-zero targets. This study presents a practical control strategy for achieving up to ~100% added CO2 capture (i.e. the exit CO2 is equivalent to the CO2 in the combustion air), with moderate energy inputs of 3.55-3.65 GJ/tCO2 comparable to 95% capture operation. The method, which efficiently minimises desorber lean loading while closely regulating lean solvent flow to the absorber, is illustrated using process modelling and validated by data from a 75-hour continuous period of ~100% capture in pilot testing at 30 tCO2/day scale. Implementation required only minimal operator training and standard plant instrumentation alongside a flue gas analyser suitable for the resulting ~ 500 ppmv exit CO2 levels. The control approach appears highly transferrable to all commercial amine capture facilities. This paper provides actionable insights for plant design, particularly key instrumentation provisions, and supports permitting guidelines for regulators.