Comparison between intensified absorber and conventional absorber

For this study, Table 7 is used as the input conditions for the conventional absorber and intensified absorber using RPB. In both simulation runs, the capture level was fixed at 90%. The flue gas conditions for the intensified absorber using RPB were also maintained the same for the conventional absorber simulation. L/G ratio used for the conventional absorber was adapted from Canepa et al. (2013). MEA concentration of the conventional absorber was kept at 30.48 wt% to minimize the problem of corrosion. It is believed that size of conventional absorber with packed column as reported by Lawal et al. (2012) is huge and using stainless steel as material of construction is too expensive. But for RPB absorber, the size of the intensified absorber can drastically reduced compared to conventional absorber (Ramshaw and Mallinson, 1981). The use of stainless steel as material of construction is feasible. In the RPB absorber simulation, MEA concentration of 74 wt% is used. Modelling and simulation of intensified absorber using RPB was done at rotor speed of 1000 rpm.

Keeping the CO₂ capture level at 90%, the simulation results of the conventional absorber using packed column and intensified absorber using RPB are shown in Table 8. Calculating the volume of the conventional absorber and RPB absorber without the sump, it was found that conventional absorber is 12 times the volume of RPB using the assumption in Agarwal et al. (2010) that the casing volume of RPB is taken as 4.5 times the RPB volume. In RPB absorber, MEA concentration is higher than what was used in the conventional absorber that is why the lean loading in RPB is lower than what was found in conventional absorber. But looking at the rich loading in both cases it can be seen that there is significant increase in rich-MEA loading in RPB absorber than the convention absorber which means more CO₂ in flue gas stream has been absorbed.