Adsorption characteristics of methane on Maxsorb III by gravimetric method

Abstract

Adsorption characteristics of CH4 on the carbonaceous porous material is evaluated for possible application in adsorbed natural gas (ANG) system. Adsorption uptakes at assorted temperatures (25-80 degrees C) and pressures ranging from ambient to relatively high pressure i.e., 8.0 MPa are experimentally investigated. Surface characteristics such as pore surface area, micropore volume and pore size distribution of the adsorbent (Maxsorb III) are first evaluated using Classical Volumetric Method i.e., the manometric method with N-2 gas adsorption at 77 K. The sorption measurements for methane, CH4 gas are carried out by thermogravimetric (TGA) method using magnetic suspension balance coupled with the automatic dosing system. The buoyancy measurements were first conducted using Helium gas as adsorbate. Buoyancy correction is applied to all sets of measured data and the specific uptake capacities (g/g of adsorbent) at various temperatures and pressures were calculated. The isotherm data were then fitted using Langmuir and Toth isotherm models. It is observed that the data can be satisfactorily fitted using Toth model with excellent fitting accuracy around 2.2% within the experimental range. The outcome of the present study especially the adsorption data at high pressures is applicable to accurate design and modeling of Adsorbed Natural Gas (ANG) systems. (C) 2014 Elsevier Ltd. All rights reserved.