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Title: Thermodynamic and mass transfer modeling of carbon dioxide absorption into aqueous 2-amino-2-methyl-1-propanol

Explanations for the mass transfer behavior of 2-amino-2-methyl-1-propanol (AMP) are conflicting, despite extensive study of the amine for CO 2 capture. At equilibrium, aqueous AMP reacts with CO 2 to give bicarbonate in a 1:1 ratio. While this is the same stoichiometry as a tertiary amine, the reaction rate of AMP is 100 times faster. This work aims to explain the mass transfer behavior of AMP, specifically the stoichiometry and kinetics. An eNRTL thermodynamic model was used to regress wetted-wall column mass transfer data with two activity-based reactions: formation of carbamate and formation of bicarbonate. Data spanned 40–100 C and 0.15–0.60 mol CO 2/mol alk). The fitted carbamate rate constant is three orders of magnitude greater than the bicarbonate rate constant. Rapid carbamate formation explains the kinetics, while the stoichiometry is explained by the carbamate reverting in the bulk liquid to allow CO 2 to form bicarbonate. Understanding the role of carbamate formation and diffusion in hindered amines enables optimizing solvent amine concentration by balancing viscosity and free amine concentration. Furthermore, this improves absorber design for CO 2 capture.
Authors:
ORCiD logo [1] ;  [1]
  1. The Univ. of Texas at Austin, Austin, TX (United States)
Publication Date:
Grant/Contract Number:
FE0013118
Type:
Accepted Manuscript
Journal Name:
Industrial and Engineering Chemistry Research
Additional Journal Information:
Journal Name: Industrial and Engineering Chemistry Research; Journal ID: ISSN 0888-5885
Publisher:
American Chemical Society (ACS)
Research Org:
The Univ. of Texas at Austin, Austin, TX (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
20 FOSSIL-FUELED POWER PLANTS; CO2 capture; separations; amine scrubbing; hindered amine; carbamate stability
OSTI Identifier:
1337599

Sherman, Brent J., and Rochelle, Gary T.. Thermodynamic and mass transfer modeling of carbon dioxide absorption into aqueous 2-amino-2-methyl-1-propanol. United States: N. p., Web. doi:10.1021/acs.iecr.6b03009.
Sherman, Brent J., & Rochelle, Gary T.. Thermodynamic and mass transfer modeling of carbon dioxide absorption into aqueous 2-amino-2-methyl-1-propanol. United States. doi:10.1021/acs.iecr.6b03009.
Sherman, Brent J., and Rochelle, Gary T.. 2016. "Thermodynamic and mass transfer modeling of carbon dioxide absorption into aqueous 2-amino-2-methyl-1-propanol". United States. doi:10.1021/acs.iecr.6b03009. https://www.osti.gov/servlets/purl/1337599.
@article{osti_1337599,
title = {Thermodynamic and mass transfer modeling of carbon dioxide absorption into aqueous 2-amino-2-methyl-1-propanol},
author = {Sherman, Brent J. and Rochelle, Gary T.},
abstractNote = {Explanations for the mass transfer behavior of 2-amino-2-methyl-1-propanol (AMP) are conflicting, despite extensive study of the amine for CO2 capture. At equilibrium, aqueous AMP reacts with CO2 to give bicarbonate in a 1:1 ratio. While this is the same stoichiometry as a tertiary amine, the reaction rate of AMP is 100 times faster. This work aims to explain the mass transfer behavior of AMP, specifically the stoichiometry and kinetics. An eNRTL thermodynamic model was used to regress wetted-wall column mass transfer data with two activity-based reactions: formation of carbamate and formation of bicarbonate. Data spanned 40–100 C and 0.15–0.60 mol CO2/mol alk). The fitted carbamate rate constant is three orders of magnitude greater than the bicarbonate rate constant. Rapid carbamate formation explains the kinetics, while the stoichiometry is explained by the carbamate reverting in the bulk liquid to allow CO2 to form bicarbonate. Understanding the role of carbamate formation and diffusion in hindered amines enables optimizing solvent amine concentration by balancing viscosity and free amine concentration. Furthermore, this improves absorber design for CO2 capture.},
doi = {10.1021/acs.iecr.6b03009},
journal = {Industrial and Engineering Chemistry Research},
number = ,
volume = ,
place = {United States},
year = {2016},
month = {12}
}