Biphasic solvent for CO2 capture: Amine property-performance and heat duty relationship

Yao Shen, Chenkai Jiang, Shihan Zhang, Jun Chen, Lidong Wang and Jianmeng Chen

Applied Energy, 2018, vol. 230, issue C, 726-733

Abstract: The main issue related to the deployment of the absorption based technology for CO2 capture is the intensive energy penalty. Biphasic solvent is regarded as a promising candidate for CO2 capture due to its potential in significant reduction of the energy consumption. However, currently, the development of biphasic solvents relies on the intensity of solvent screening work. To address this issue, this work investigated the relationships between the solvent properties and CO2 capture performance such as absorption capacity, phase separation behavior, kinetics, and thermodynamics. Ten primary/secondary amines and eight tertiary amines with different alkalinity (pKa) and hydrophobicity (Log P) were used as the main components of the biphasic solvent. Experimental results revealed that the tertiary amine’s alkalinity determines the absorption capacity of the biphasic solvent. The maximum CO2 absorption capacity was achieved by the tested biphasic solvent with a tertiary amine of a pKa around 9.8. Compared with the tertiary amine, the primary amine’s hydrophobicity was more sensible to the phase separation behavior of the solvent. The low Log P value of the primary amine and the high Log P value of the tertiary amine befitted the phase separation. Kinetic analysis indicate that the total mass transfer resistance of the rich solution decreased with the increase in the Log P value of the tertiary amine. Interestingly, the highest enhancement factor was achieved by the tertiary amine (2-(diethylamino)ethanol) with the pKa of 9.79. Further increase of the tertiary amine’s pKa decreased the enhancement factor of the biphasic solvent. This was attributed to the limitation of mass transfer of tertiary amine from the upper phase to lower phase. Furthermore, thermodynamic analysis showed that the sensible heat and the latent heat of the solvents decreased and increased, respectively, with the increase of log P value of the tertiary amines. The lowest reaction enthalpy and heat duty of the tested biphasic solvents were 45.8% and 52% lower than those of the benchmark monoethanolamine solution, respectively. Overall, compared with the primary amine, the selection of the tertiary amine is more important to achieve a great performance for CO2 capture. Therefore, the tertiary amine with a moderate pKa and Log P is beneficial to achieve a high absorption capacity, fast absorption rate, and low heat duty of the biphasic solvent.

Keywords: CO2 capture; Biphasic solvent; Amine property; Kinetics; Heat duty (search for similar items in EconPapers)
Date: 2018
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (22)

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0306261918313060
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:appene:v:230:y:2018:i:c:p:726-733

Ordering information: This journal article can be ordered from
http://www.elsevier.com/wps/find/journaldescription.cws_home/405891/bibliographic
http://www.elsevier. ... 405891/bibliographic

DOI: 10.1016/j.apenergy.2018.09.005

Access Statistics for this article

Applied Energy is currently edited by J. Yan

More articles in Applied Energy from Elsevier
Bibliographic data for series maintained by Catherine Liu ().