Structure and Activity Relationships for CO2 Regeneration from Aqueous Amine Based Absorbents
Advancing the chemical engineering fundamentals
Distillation, Absorption & Extraction - I (T2-10a)
Keywords: Desorption, CO2, alkanolamine, acid gases, regeneration.
Abstract
Although the absorption of acid gases such as CO2 in aqueous amine solutions like e.g. MEA (monoethanolamine) from natural gas concerns proven technology, the removal of CO2 from flue gases is not as straightforward as it could be expected. In these currently used systems a major part of the operational cost is caused by the solvent regeneration (up to 40%). In industrial processes, very high temperatures (>100 oC) are used to regenerate MEA solutions. Usually high pressure steam is applied, which provides the heat of reaction and enables the transport of CO2 out of the reactor. The regeneration process is usually done at the temperature in excess of the boiling temperature, as the chemical kinetics of regeneration increases with temperature. Although desorption processes often act as regenerative processes for absorption systems, studies devoted to desorption are not as numerous as those concerning absorption. More specifically, the relationship of structure and regeneration characteristics of various amines based absorbent for CO2 is hardly studied.
Therefore, a screening method has been investigated for the regeneration of CO2 from various loaded amine based aqueous absorbents at low temperature and atmospheric pressure with rapid regeneration rate and low evaporation solution loss. Desorption of CO2 from various amine based absorbents will be measured to assess the amount of CO2 desorbed and the rate of desorption at 60-80 oC. In a typical experiment first the amine based absorbent is saturated with CO2. The total CO2 loading of the absorbent is determined by a desorption/titration procedure as described by Blauwhoff et al (1984). After which the known amount of saturated absorbent is transferred into the desorption vessel where CO2 is released and that amount of CO2 is being measured by inline CO2 IR detector. The total CO2 loading in the desorbed absorbent is determined by desorption/titration procedure as described by Blauwhoff et al (1984).
In these experiments the effects which will be investigated are the chain length, number of functional groups, different functional groups at the α-carbon, cyclic amine and substituted cyclic amines. Based on the results a better understanding of the structural effect on CO2 desorption will be developed. This study will be advantageous in the development of an improved amine based CO2 absorbent, lead to a better approach for development of new technologies in the CO2 capture area.
References:
Blauwhoff P.M.M., Versteeg G.F. Van Swaaij W.P.M., A study on the reaction between CO2 and alkanolamines in aqueous solutions. Chemical Engineering Science 1984, pp 207-225.
See the full pdf manuscript of the abstract.
Presented Monday 17, 11:15 to 11:33, in session Distillation, Absorption & Extraction - I (T2-10a).
