skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Evaluating methane adsorbed film densities on activated carbon in dynamic systems

Journal Article · · Journal of Energy Storage
 [1];  [1];  [1];  [1];  [1];  [2];  [1]
  1. Univ. of Missouri, Columbia, MO (United States)
  2. Lebanese American University, Byblos (Lebanon)

Dynamic methane loading and discharge experiments on a 40 L adsorbed natural gas tank containing 20.5 kg of monolithic carbon adsorbent have been combined with pore volume data from subcritical nitrogen isotherms to evaluate the density and dynamic properties associated with adsorbed methane. The time-dependent density of the adsorbed gas was evaluated for narrow and wide micropores. The temperature-dependent adsorbed film volume was determined from the Ono-Kondo model and compared with the total micropore volume. The resulting adsorbed methane density evolves in two distinct parts. The density increases rapidly during the beginning of the loading process and increases slowly after narrow pores reach saturation. The narrow pores’ saturated adsorbed gas densities ranged from 0.26 – 0.35 kg/L, depending on the choice of film volume. The density of wide micropores was found to be highly dependent on the loading procedure due to the expected temperature dependence of the film volume. During discharge, it was found that the wide micropores deplete early while narrow micropores deplete slowly which causes the less than 100% efficient discharges seen in adsorbed natural gas systems. These density models have been applied to accurately predict the gravimetric excess adsorption of other carbon adsorbents at 35 bar and explain previously published pressure and temperature relations during tank loading.

Research Organization:
Univ. of Missouri, Columbia, MO (United States)
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Grant/Contract Number:
FG36-08GO18142
OSTI ID:
1613540
Alternate ID(s):
OSTI ID: 1637206
Journal Information:
Journal of Energy Storage, Vol. 20, Issue C; ISSN 2352-152X
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 3 works
Citation information provided by
Web of Science

References (19)

Research on the theory and application of adsorbed natural gas used in new energy vehicles: A review journal May 2016
Microporous carbon monolith synthesis and production for methane storage journal July 2017
Classification of Gibbs adsorption isotherms journal July 1998
Controlled charge and discharge of a 40-L monolithic adsorbed natural gas tank journal July 2018
Complex pore spaces create record-breaking methane storage system for natural-gas vehicles journal December 2007
Methane adsorption in nanoporous carbon: the numerical estimation of optimal storage conditions journal May 2016
A pilot study of activated carbon and metal–organic frameworks for methane storage journal January 2016
Modeling of High-Pressure Adsorption Isotherms above the Critical Temperature on Microporous Adsorbents:  Application to Methane journal February 1997
Nanospace engineering of KOH activated carbon journal December 2011
Influence of pore geometry on the design of microporous materials for methane storage journal January 1993
Grand Canonical Monte Carlo Simulation Study of Methane Adsorption at an Open Graphite Surface and in Slitlike Carbon Pores at 273 K journal June 2005
A New Equation of State and Tables of Thermodynamic Properties for Methane Covering the Range from the Melting Line to 625 K at Pressures up to 100 MPa journal November 1991
Reporting physisorption data for gas/solid systems with special reference to the determination of surface area and porosity (Recommendations 1984) journal January 1985
Contribution to the Evaluation of Density of Methane Adsorbed on Activated Carbon journal November 2005
Influence of exhaust gas heating and L/D ratios on the discharge efficiencies for an activated carbon natural gas storage system journal April 2014
Cycling and Regeneration of Adsorbed Natural Gas in Microporous Materials journal November 2017
Combination volumetric and gravimetric sorption instrument for high accuracy measurements of methane adsorption journal May 2017
Adsorbed methane storage for vehicular applications journal July 2015
Advances in the study of methane storage in porous carbonaceous materials journal September 2002