A new pilot absorber for CO2 capture from flue gases: Measuring and modelling capture with MEA solution

A pilot absorber column for CO2 recovery from flue gases was constructed and tested with aqueous 30wt% monoethanolamine (MEA), a primary amine, as capture solvent. The pilot plant data were compared with a mathematical rate based packed-column model. The simulation results compared well with the pilot plant data.

The packed height of the column can be varied from 1.6 to 8.2. m by means of five different liquid inlets. The column has an inner diameter of 100. mm and is packed with structured Mellapak 250Y packing. Counter-current flow is used. The pilot plant performance was investigated by changing three parameters: the absorption height, liquid flow rate, and the loading of lean MEA.

This was done using a synthetic flue gas consisting of 10% CO2 with a flow rate of approximately 33m3/h at ambient temperature and atmospheric pressure. 23 runs were performed. It was observed that while CO2 recovery increases with an increase in flow rate of absorbent and absorption height, it decreases as the lean CO2-loading of the absorbent increases.

In addition it has been possible to obtain temperature bulges in the bottom part of the absorber by the applied operation conditions. Bulges are observed at liquid flows around 4.2L/min and below. The results showed that is was possible to achieve 80% recovery with 3.3m absorption height and a liquid flow of 2.1L/min.

The simulations show good agreement with the experimental values, although slight deviations arise as the CO2-loading increases and the temperature bulge becomes more distinct.