Dynamic analysis of the absorption/desorption loop of a carbon capture plant using an object-oriented approach

Post-combustion capture of CO2 is regarded as a possible technology in order to reduce CO2 emission to the atmosphere. This paper provides a dynamic analysis of the absorption/desorption loop of a carbon capture plant with the help of a simulation model, built using the object-oriented Modelica Library Thermal Separation. The solvent used is an amino-acid salt.The dynamic behaviour is investigated for a reduction in regeneration heat flow rate but constant flue gas flow rate. Hereby four different control strategies are compared, one keeping the lean solvent loading constant, one keeping the solvent flow rate constant, one where flue gas bypasses the capture plant and a last one where an additional solvent tank is introduced. The simulation shows i.e. that for a constant lean solvent loading the response of the absorbed CO2 flow rate is much faster than for a constant solvent flow rate.Also the effect on the dynamic behaviour is investigated, comparing the whole cycle model to a stand-alone desorber model and to a stand-alone absorber model respectively. It was found that the dynamic responses on a short time scale are very similiar, but different on a long time scale.

► Dynamic model for investigation of CO2 capture plant was set up.
► Different strategies for handling steam reduction result in different dynamic behaviour.
► Simulating whole cycle has no remarklable effect on the short-term dynamic behaviour compared to stand-alone models.
► Investigation of solvent storage.