Energy-saving CO2 capture using sulfolane-regulated biphasic solvent. (15th November 2020)

• Record Type: Journal Article
• Authors: Wang, Rujie; Jiang, Lei; Li, Qiangwei; Gao, Ge; Zhang, Shihan; Wang, Lidong
• Is Part Of: Energy. Volume 211(2020)
• Publication Date: 2020-11-15
• Subjects: Biphasic solvent -- Phase splitter -- Regeneration heat consumption -- Phase separation -- CO2 capture; Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Energy consumption -- Periodicals; 333.7905
• DOI: 10.1016/j.energy.2020.118667
• Languages: English
• ISSNs: 0360-5442

Abstract

Abstract: Because of phase separation characteristics, biphasic solvents are recognized as promising absorbents for CO2 capture with low regeneration heat consumption. However, limited CO2 loading in CO2 -rich phase, associated with excessive CO2 -rich phase volume, challenges the energy-saving regeneration potential of mixed-amine biphasic solvents. In this study, sulfolane was employed as a phase splitter to improve the phase separation properties of N, N-diethylenetriamine (DETA)-N, N, N′, N″, N″-pentamethyldiethylenetriamine (PMDETA) biphasic absorbent. By introducing the hydrophobic sulfolane, large CO2 capacity (increased from 3.56 to 6.48 mol/L) and low CO2 -rich phase volume (decreased from 100% to 27.1%) were simultaneously achieved. Moreover, sulfolane acted as an absorption accelerator to increase the CO2 absorption rate in DETA-PMDETA-sulfolane solvent to 1.3 times the corresponding DETA-PMDETA solvent. Benefiting from the large CO2 capacity associated with favorable phase separation behavior, DETA-PMDETA-sulfolane has a minimized regeneration heat estimated at 1.86 GJ/t-CO2 at a lean CO2 -loading of 0.55 mol/mol. This is 53.4% lower than the regeneration heat (3.99 GJ/t-CO2 ) using 5 M monoethanolamine solvent. Graphical abstract: Image 1 Highlights: The phase separation of DETA-PMDETA biphasic solvent was regulated by sulfolane. Simultaneous improvements on volume ratio and CO2 loading were obtained. A decreased regeneration heat, 1.86 GJ/t CO2, were achieved, 53% lower than 5 M MEA.