(446a) Influence of Phase Transition Temperature on CO2 Adsorption/Desorption Behavior of Thermo-Responsive Gel Slurry

ã??Reduction of CO₂ emissions from fossil fuel power plants and relating industrial factories is becoming increasingly important for addressing climate change concern. Development of efficient technology to capture and recover CO₂ from flue gas is an important issue. Major commercial method for CO₂ recovery from flue gas is chemisorption using amine-based sorbent. This method is energy consuming in desorption and regeneration process of the sorbent. Thus, cost effective process in the regeneration of spent sorbent and an eco-recovery of chemisorbed CO₂should be required. Therefore, researches for energy saving chemisorption process have been attracting much attention for decade.

ã??In this study, thermo-responsive hydrogel copolymerized with amine monomer was examined as an energy saving CO₂ adsorbent. The thermo-responsive hydrogel reveals volume phase transition from a swollen â??hydrophilicâ? state to a collapsed â??hydrophobicâ? state at its lower critical solution temperature (LCST). Preceding study performed by other research group indicated the potential of this recovery concept. Using the thermo-reversible change in adsorption capacity of the gel for CO₂, selective separation and recovery of CO₂ is available. The potential advantage of the thermos-responsive hydrogel in the chemisorbed CO₂ recovery is large reduction of desorption/regeneration temperature due to pKa shift of amine group accompanied with the volume change of the gel. Poly(N-isopropylacrylamide)-polyamine copolymer hydrogel slurry was synthesized as the thermo-responsive adsorbent for CO₂ in this study. Temperature swing adsorption and desorption experiments of CO₂ were performed using CSTR (Continuous Stirred Tank Reactor) type gas flow adsorber. The LCST of the gel was controlled based on the additives in the system solution. Influence of the LCST shift on the CO₂adsorption/desorption properties was investigated. 

References

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