Model verification and analysis of the CO2-MEA absorber-desorber system

Processes applied for the capturing of carbon-dioxide from industrial gases are in the focus of the reduction of green-house gas emission. The highest amount of anthropogenic CO2 is emitted in flue gas form but with varying gas composition according to the source and the circumstance of the combustion of fossil fuel. A typical method for such CO2 capturing is an absorber-desorber system where the absorbent is quite frequently 30 wt% aqueous monoethanolamine (MEA) solution. The aim of our work is to setup an adequate and verified computer based process model that is capable for the rigorous simulation and analysis of the treatment of various flue gases, evaluating the purification of different types of flue gases to see the environmental aspect and further possible process improvements. For the verification of the absorber-desorber model, measured data are applied. The data are obtained on an existing absorber-desorber system of pilot plant size for the cases of two different test gases of different compositions. It is shown and explained why the equilibrium stage model is not accurate in such cases but the non-equilibrium stage assumption, that is, the rate based modeling is suitable. Modeling explains the reasons of why the operation with less absorbent need higher energy for the operation than the optimal one and shows the effect of carbon footprint of the energy demand achieved with various fuels used for desorber heating.