TY - JOUR

T1 - Analysis of optimal conditions for adsorptive hydrogen storage in microporous solids

AU - Bimbo, Nuno

AU - Ting, Valeska P.

AU - Sharpe, Jessica E.

AU - Mays, Timothy J.

PY - 2013/11/20

Y1 - 2013/11/20

N2 - There is much current interest in the storage of hydrogen in porous materials for mobile energy applications. Despite significant hydrogen storage capacities having been observed recently for some synthesised materials, the identification of optimal operating conditions (pressure and temperature) is perhaps an even more important consideration from an engineering and applied science perspective. There will be pressure and temperature limits for effective use of an adsorptive storage system, because the adsorbent will always displace a volume in the storage container, and so at very high pressures the amount of hydrogen stored at a given temperature will be greater for a container with no adsorbent. In order for an adsorbent to be used there has to be some gain in the amount of the hydrogen stored to compensate for the cost and mass of the solid. We present a methodology by which the pressure and temperature ranges where it is advantageous to use adsorptive storage can be easily identified and the real gain of using such systems in terms of the absolute amount of hydrogen stored can be quantified. Using a well-characterised commercial activated carbon as an example system, we modelled high pressure hydrogen sorption isotherms and identified the operating conditions for which there is a significant increase in storage capacity from using an adsorbent as opposed to storage in the same volume via compression of hydrogen at the same temperature. A novel comparison of the density enhancement in the micropores with respect to the bulk hydrogen gas, as well as the influence of incorporating different amounts of adsorbent into a high pressure storage container is also presented. (C) 2012 Elsevier B.V. All rights reserved.

AB - There is much current interest in the storage of hydrogen in porous materials for mobile energy applications. Despite significant hydrogen storage capacities having been observed recently for some synthesised materials, the identification of optimal operating conditions (pressure and temperature) is perhaps an even more important consideration from an engineering and applied science perspective. There will be pressure and temperature limits for effective use of an adsorptive storage system, because the adsorbent will always displace a volume in the storage container, and so at very high pressures the amount of hydrogen stored at a given temperature will be greater for a container with no adsorbent. In order for an adsorbent to be used there has to be some gain in the amount of the hydrogen stored to compensate for the cost and mass of the solid. We present a methodology by which the pressure and temperature ranges where it is advantageous to use adsorptive storage can be easily identified and the real gain of using such systems in terms of the absolute amount of hydrogen stored can be quantified. Using a well-characterised commercial activated carbon as an example system, we modelled high pressure hydrogen sorption isotherms and identified the operating conditions for which there is a significant increase in storage capacity from using an adsorbent as opposed to storage in the same volume via compression of hydrogen at the same temperature. A novel comparison of the density enhancement in the micropores with respect to the bulk hydrogen gas, as well as the influence of incorporating different amounts of adsorbent into a high pressure storage container is also presented. (C) 2012 Elsevier B.V. All rights reserved.

KW - Hydrogen storage

KW - Porous materials

KW - Adsorption

KW - Compressed hydrogen systems

KW - INSULATED PRESSURE-VESSELS

KW - METAL-ORGANIC FRAMEWORKS

KW - NANOPOROUS MATERIALS

KW - ACTIVATED CARBONS

KW - WIDE TEMPERATURE

KW - POROUS MATERIALS

KW - ENERGY CARRIER

KW - GAS-STORAGE

KW - ADSORBENTS

KW - CAPACITIES

U2 - 10.1016/j.colsurfa.2012.11.008

DO - 10.1016/j.colsurfa.2012.11.008

M3 - Journal article

VL - 437

SP - 113

EP - 119

JO - Colloids and Surfaces A: Physicochemical and Engineering Aspects

JF - Colloids and Surfaces A: Physicochemical and Engineering Aspects

SN - 0927-7757

T2 - 6th International Workshop on Characterization of Porous Materials - from Angstroms to Millimeters (CPM)

Y2 - 30 April 2012 through 2 May 2012

ER -