Title

An investigation into the absorption of CO2 by amine-coated polymeric supports

Date of Completion

January 2003

Keywords

Engineering, Chemical

Degree

Ph.D.

Abstract

A variety of liquid amines have been used and investigated for removing carbon dioxide from gas streams. Several prior studies have concentrated on determining the kinetics and mass transport for a variety of aqueous amine solutions. ^ This subject research study was used to classify differences in the reaction of a variety of amine types with carbon dioxide. Unlike previous research, this investigation was directed to investigating the effectiveness of amines while immobilized within the pores of a non-ionic polymeric (polymethylmethacrylate, PMMA) support. These combined amine-support solid absorbent particles behave macroscopically as a benign solid absorbent, and will be referred to as “solid amines”. ^ Specifically this research examined the effect of converting amine molecules containing primary and/or secondary amine groups into molecules with a preponderance of secondary amine functionality. This research examined the formation of Michael addition products as a method of converting primary amines into secondary amines. The ability of these amine molecules was examined both before and after the reaction forming the Michael addition products. The desirability of these modified amines at removing carbon dioxide from a gas stream at the low levels found in life support applications (∼7.6 mm Hg) was emphasized. ^ This research also examined the effects of amine loadings on carbon dioxide removal capacity. Specifically the ability of these novel solid amines to operate in a pressure swing absorption mode was investigated. This work measured the cyclic and equilibrium capacity for carbon dioxide removal for a variety of fabricated solid absorbents. Finally, basic thermodynamic and chemical properties of the amines formed via the Michael reaction were measured to determine their influence in the CO2 absorption process. These properties included boiling point, viscosity, heat of absorption and surface tension. ^