1 research outputs found
Rational Design of the Polymeric Amines in Solid Adsorbents for Postcombustion Carbon Dioxide Capture
Substantial
efforts have been made to increase the CO<sub>2</sub> working capacity
of amine adsorbents for an efficient CO<sub>2</sub> capture. However,
the more important metric for assessing adsorbents is the regeneration
heat required for capturing a fixed amount of CO<sub>2</sub>. In this
work, we synthesized polyethyleneimine (PEI)/SiO<sub>2</sub> adsorbents
functionalized with various epoxides. This provided adsorbents with
six different amine structures showing various CO<sub>2</sub>/H<sub>2</sub>O adsorption properties. Our studies revealed that the CO<sub>2</sub> working capacity was not a decisive factor in determining
the regeneration heat required for CO<sub>2</sub> capture. This is
because the benefit of large CO<sub>2</sub> working capacity was canceled
out by the difficulty of CO<sub>2</sub> desorption. Instead, the suppression
of H<sub>2</sub>O co-adsorption was critical for reducing the regeneration
heat because substantial latent heat is required for H<sub>2</sub>O desorption. Consequently, the PEI/SiO<sub>2</sub> functionalized
with 1,2-epoxybutane required a much lower regeneration heat (2.66
GJ tCO<sub>2</sub><sup>β1</sup>) than the conventional PEI/SiO<sub>2</sub> (4.03 GJ tCO<sub>2</sub><sup>β1</sup>) because of
suppressed H<sub>2</sub>O co-adsorption as well as moderately high
CO<sub>2</sub> working capacity