Mesoporous carbon xerogel as a promising adsorbent for capture and storage of liquified natural gas vapors.

Capture and storage of LNG vapors in the adsorbed state is envisioned as an effective way to improve the LNG terminal performance. A synthetic carbon xerogel was proposed as a promising adsorbent for methane vapors in the LNG terminal combined with an adsorbed natural gas (ANG) module. The textural properties of the adsorbent were investigated by X-ray diffraction, scanning electron microscopy, and low-temperature nitrogen adsorption. An approach based on the theories of volume filling of micropores, a monolayer capacity on the mesopore surface, and the capillary condensation in the mesopores was applied to the experimental data on methane adsorption to evaluate the adsorption capacity of the adsorbent over the sub- and supercritical P,T-ranges. It was found that the capillary condensation of methane in mesopores ensured an extraordinary adsorption capacity of the adsorbent, achieving 540 m³(NTP)·m⁻³ at the boiling point. The adsorption- and temperature-induced deformation of the adsorbent, and the thermal effects arising during adsorption were examined with a view of the performance of the LNG terminal combined with the adsorber for capturing and accumulating LNG vapors. The ANG tank loaded with the carbon xerogel ensured the maximum amount of gas supplied to the consumer at temperatures close to 140 K. A comparison of the adsorption performances of the carbon xerogel and a commercial activated carbon characterized by a wider pore size distribution made it possible to identify a difference in the optimal operational conditions of their application for the LNG–ANG technology. [ABSTRACT FROM AUTHOR]