Pre-evaluation of a new process for capture of CO₂ using water

A new concept for CO₂ capture by absorption into water was briefly assessed. In this concept, CO₂ is captured from flue gas in a pressurized bubble-type absorption column. Desorption of CO₂ takes place by flashing the water at sub-atmospheric pressure (0.4 bar). This leaves a relatively high concentration of CO₂ in the Water. The new concept introduces a post-desorber that enables lowering the CO₂ concentration of the water further by flashing the water stream into the flue gas. This enables a higher CO₂ capture efficiency at chosen pressure level than possible with other water CO₂ capture concepts. The preliminary energy requirements and equipment cost seems to be similar to those of amine-based CO₂ capture processes. However, more work is needed to verify these preliminary results. The water-based CO₂ amine-based concepts. The water requirements are still very high so for the process to be feasible (in terms of energy requirements) it requires an external source of cooling water, i.e. preliminary results indicate that the new water-wash concept could possibly be competitive to amine-based processes for CO₂ capture at a small scale (~50 kt CO₂ per year), more work is needed to assess the performance and cost of the concept at a large-scale power plant circulation than amine-based processes it is possible that at larger scales amine-based processes may be favourable (e.g. due to space requirements and technical challenges related to circulation of very large amounts of water). Still, the new water-based CO₂ capture concept seems promising based on this initial assessment and warrants further work.