Kinetics and enthalpies of methane adsorption in microporous materials AX-21, MIL-101 (Cr) and TE7
Kinetics and enthalpies of methane adsorption in microporous materials AX-21, MIL-101 (Cr) and TE7
Methane is touted as a replacement for fossil fuels in transport applications due to its lower costs of production and cleaner combustion. Storage of methane is still a problem and different technologies have been considered, including compression and liquefaction. Adsorption in a porous material is a potential alternative for methane storage, as it can increase densities at moderate pressures and temperatures. For practical applications, in addition to the quantities stored and working capacities, it is important to equally consider aspects such as kinetics of storage and thermal management of the storage system. In this paper, the kinetics and enthalpies of adsorption of methane in activated carbons AX-21 and TE7, and metal-organic framework MIL-101 (Cr) are extracted from readily available gas sorption data. The adsorption kinetics at 300K and 325K are analysed and fitted with the linear driving force (LDF) model, and mass transfer coefficients (MTC) and effective diffusivities are estimated. The effective diffusivities have a range of values from 1.79×10−13 m2 s−1 for the MIL-101 (Cr) at 300K to 9.36×10−10 m2 s−1 for the TE7 at 325K. The activation energies for the effective diffusivities based on an Arrhenius-type temperature dependence are calculated as 7.42, 7.09 and 5.38kJmol−1 for the AX-21, the MIL-101 (Cr) and the TE7, respectively. The enthalpies of adsorption are calculated with the Clausius-Clapeyron equation and the differences observed when calculating these with excess and absolute amounts are presented and discussed, with the results showing that enthalpies can have up to 10% differences if using excess amounts instead of absolute quantities. The isosteric enthalpies are also compared with enthalpies at zero-coverage obtained from differential calorimetry experiments for the MIL-101 (Cr), and a ∼3.5kJmol−1 difference is observed, which underlines the importance of refining calculation methods and bridging the gap between direct and indirect methods for calculating enthalpies of adsorption.
enthalpies of adsorption., kinetics, methane adsorption, methane storage
153-164
Bimbo, Nuno
53d9fc24-e2c1-4e2d-8d75-8dc640d8adda
Smith, Joseph P.
4eb138ea-3da5-43ea-ad79-bb1d70a62178
Aggarwal, Himanshu
595f81b1-034e-4412-b632-b957b6b932e0
Physick, Andrew J.
bbdea60b-bb76-480a-91d4-5f9d2f5f30ae
Pugsley, Adam
b04c293b-87c8-4cf1-9c90-250baba85db5
Barbour, Leonard J.
7f70bafd-ac1d-4be9-abdf-35d0a871f757
Ting, Valeska P.
d4381878-2aad-4a3f-a7cc-021a7f7075eb
Mays, Timothy J.
d02351c7-1d8f-4a9e-8d16-675c1f7b3635
May 2021
Bimbo, Nuno
53d9fc24-e2c1-4e2d-8d75-8dc640d8adda
Smith, Joseph P.
4eb138ea-3da5-43ea-ad79-bb1d70a62178
Aggarwal, Himanshu
595f81b1-034e-4412-b632-b957b6b932e0
Physick, Andrew J.
bbdea60b-bb76-480a-91d4-5f9d2f5f30ae
Pugsley, Adam
b04c293b-87c8-4cf1-9c90-250baba85db5
Barbour, Leonard J.
7f70bafd-ac1d-4be9-abdf-35d0a871f757
Ting, Valeska P.
d4381878-2aad-4a3f-a7cc-021a7f7075eb
Mays, Timothy J.
d02351c7-1d8f-4a9e-8d16-675c1f7b3635
Bimbo, Nuno, Smith, Joseph P., Aggarwal, Himanshu, Physick, Andrew J., Pugsley, Adam, Barbour, Leonard J., Ting, Valeska P. and Mays, Timothy J.
(2021)
Kinetics and enthalpies of methane adsorption in microporous materials AX-21, MIL-101 (Cr) and TE7.
Chemical Engineering Research and Design, 169, .
(doi:10.1016/j.cherd.2021.03.003).
Abstract
Methane is touted as a replacement for fossil fuels in transport applications due to its lower costs of production and cleaner combustion. Storage of methane is still a problem and different technologies have been considered, including compression and liquefaction. Adsorption in a porous material is a potential alternative for methane storage, as it can increase densities at moderate pressures and temperatures. For practical applications, in addition to the quantities stored and working capacities, it is important to equally consider aspects such as kinetics of storage and thermal management of the storage system. In this paper, the kinetics and enthalpies of adsorption of methane in activated carbons AX-21 and TE7, and metal-organic framework MIL-101 (Cr) are extracted from readily available gas sorption data. The adsorption kinetics at 300K and 325K are analysed and fitted with the linear driving force (LDF) model, and mass transfer coefficients (MTC) and effective diffusivities are estimated. The effective diffusivities have a range of values from 1.79×10−13 m2 s−1 for the MIL-101 (Cr) at 300K to 9.36×10−10 m2 s−1 for the TE7 at 325K. The activation energies for the effective diffusivities based on an Arrhenius-type temperature dependence are calculated as 7.42, 7.09 and 5.38kJmol−1 for the AX-21, the MIL-101 (Cr) and the TE7, respectively. The enthalpies of adsorption are calculated with the Clausius-Clapeyron equation and the differences observed when calculating these with excess and absolute amounts are presented and discussed, with the results showing that enthalpies can have up to 10% differences if using excess amounts instead of absolute quantities. The isosteric enthalpies are also compared with enthalpies at zero-coverage obtained from differential calorimetry experiments for the MIL-101 (Cr), and a ∼3.5kJmol−1 difference is observed, which underlines the importance of refining calculation methods and bridging the gap between direct and indirect methods for calculating enthalpies of adsorption.
Text
Bimbo_et_al_MS_final
- Accepted Manuscript
More information
Accepted/In Press date: 6 March 2021
e-pub ahead of print date: 13 March 2021
Published date: May 2021
Additional Information:
Funding Information:
VPT acknowledges support from the UK Engineering and Physical Sciences Research Council, EPSRC (EP/R01650X/1). TJM acknowledges support from the EPSRC (EP/P024807/1, EP/L018365/1 and EP/K021109/1). NB and VPT gratefully acknowledge funding from the International Mobility Funding from the University of Bath to visit Stellenbosch and perform the DSC experiments. The authors would like to thank Dr Darren Broom (Hiden Isochema, Warrington, UK) for useful discussions.
Publisher Copyright:
© 2021 Institution of Chemical Engineers
Keywords:
enthalpies of adsorption., kinetics, methane adsorption, methane storage
Identifiers
Local EPrints ID: 448052
URI: http://eprints.soton.ac.uk/id/eprint/448052
ISSN: 0263-8762
PURE UUID: b0d2d18f-8508-45e5-bb8a-db2f21e2253a
Catalogue record
Date deposited: 01 Apr 2021 15:40
Last modified: 17 Mar 2024 06:27
Export record
Altmetrics
Contributors
Author:
Joseph P. Smith
Author:
Himanshu Aggarwal
Author:
Andrew J. Physick
Author:
Adam Pugsley
Author:
Leonard J. Barbour
Author:
Valeska P. Ting
Author:
Timothy J. Mays
Download statistics
Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.
View more statistics
