A study of methane adsorption and accumulation on microporous carbon adsorbent in a wide temperature range

Abstract

This work studies the adsorption properties of microporous activated carbon AU-2 to determine the efficiency of methane accumulation in a wide temperature range, particularly in the low temperature range. Absolute adsorption isotherms of methane are measured in the pressure range of 20 Pa to 25 MPa and temperature range of 178–260 K. It is shown that the adsorbent accumulates up to 130 m³(ntp, CH₄)/m³ at 7 MPa and 298 K. A decrease in the temperature by 55° allows reaching the value of 180 m³(ntp, CH₄)/m³. The experimental data are used to plot methane adsorption isosteres that are well approximated by straight lines in the coordinates of lnp = f(1/T)_a. The values of differential and integral adsorption heats of methane on the adsorbents are calculated on the basis of the experimental isotherms and are used to calculate an increase in the adsorber temperature as a result of adsorption.