Protea Limited

Measurement solution for CO2 capture by anime absorption

The act of capturing and storing CO2 produced from large scale combustion plants such as power stations is becoming more and more favourable and feasible. One of the most common post-combustion CO2 capture methods is by absorption. The absorption plant can be added on to the existing combustion process, with the flue gas first passing through an absorption column where the CO2 reacts with an absorber.

Amines of different types are used as the absorber. An amine CO2 capture plant can capture as much as 90% of the CO2 emitted from the power station and so has a real benefit for the environment. Having said this, care needs to be taken to ensure that amine emissions themselves are monitored, managed and prove no extra damage to the environment. Research is on-going to develop new amines or mixtures of amines to reduce emissions. The most common absorber in use in today’s first generation of industrial pilot plants is Monoethanolamine (MEA).

Once the CO2 has reacted with the aqueous amine solution, it forms a carbonate salt. The salt is then heated in a stripping column, reforming pure CO2 and pure amine. The amine can be recycled whereas the CO2 is compressed and transported away as a liquid.

During the CO2 capture process, a small amount of amine will escape from the absorber along with the cleaned flue gas. This can be as liquid droplets or as gas. With possible mixes of amines being used as well as degradation products of amines there is a need to have amine monitoring technology that can measure as many species as possible and as accurately as possible.

Protea’s FTIR gas analysers have proven capable of measurement of amines from CO2 capture facilities, enabling the pilot plant operates to understand better the emissions to atmosphere of species such as MEA. (e.g. Longannet Carbon Capture Pilot Plant, 2009)

FTIR amine analysis can be carried out in the presence of the background flue gas of NO, NO2, NOx, CO, H2O, SO2. And of course CO2 levels can be measured as well to back up mathematical modelling predictions of CO2 reduction.