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Novel Thermomorphic Biphasic Amine Solvents for CO 2 Absorption and Low‐Temperature Extractive Regeneration
Author(s) -
Zhang J.,
Misch R.,
Tan Y.,
Agar D. W.
Publication year - 2011
Publication title -
chemical engineering and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.403
H-Index - 81
eISSN - 1521-4125
pISSN - 0930-7516
DOI - 10.1002/ceat.201100099
Subject(s) - boiling point , solvent , amine gas treating , chemistry , desorption , chemical engineering , flue gas , absorption (acoustics) , countercurrent exchange , organic chemistry , materials science , adsorption , thermodynamics , engineering , composite material , physics
The key challenge in amine‐based CO 2 capture from flue gases is to reduce the energy consumption required for solvent regeneration. Lipophilic amines exhibit a thermomorphic phase transition upon heating, giving rise to autoextractive behavior, which intensifies desorption at temperatures well below the boiling point of aqueous solutions. The low regeneration temperature of less than 80 °C together with the high cyclic CO 2 loading capacity of ∼0.9 mol CO 2 mol absorbent –1 of such thermomorphic biphasic solvent (TBS) systems permit the use of low‐value and even waste heat at temperatures below 100 °C for desorption. In order to reduce the exergy demands still further, techniques for enhancing CO 2 release using extractive regeneration with inert solvent addition were investigated at temperatures of 40–50 °C to permit the use of waste heat at temperatures of ∼70 °C or less. The regeneration of 3 M absorbed lipophilic amine solutions with 0.93 mol mol –1 CO 2 loading by using various additional solvents and the evaluation of the extractive performance in multiple‐stage crosscurrent and countercurrent configurations indicated the promise of adding certain hydrophobic solvents to enhance the low‐temperature regeneration of TBS absorbents.