Optimization of gas velocity and pressure drop in CO2 absorption column

Abstract

For a traditional amine-based CO2 capture system, the absorber column accounts for a significant part of the overall capital- and operating cost. One important design factor of absorber columns is the gas velocity through the absorber packing. Higher gas velocity leads to higher energy cost due to increased pressure drop, but at the same time lower packing cost due to increased effective interfacial area. By utilizing available correlations in the new version 9.0 of the simulation program Aspen HYSYS, the cost optimum gas velocity can be determined. This work evaluated six types of structured packings: Mellapak 250X, 250Y, 2X, 2Y, Mellapak Plus 252Y and Flexipac 2Y. The simulation results show that for all the packings, the cost-optimum gas velocity is in the range of 2.0 to 2.5 m/s giving a pressure drop through the absorber in the range of 10 to 15 mbar.