The Production of Various Adsorbents from Lignite, and the Thermal Conductivity of the Optimum Adsorbent under Methane at Low Pressures

A series of adsorbents were produced from lignite by pyrolysis in a furnace over a range of temperatures, from 600 to 900°C, for half an hour. The lignite based granular chars were produced from its normal raw state, and also after chemical pre-treatment of the chars by agitation with 1 and 2% ZnC12 wt/wt solutions for one hour. Static equilibrium isotherms using methane as the adsorbate were determined at 20°C for all the samples produced, and the adsorbent with the optimum uptake determined. The actual isotherms obtained were compared against the Freundlich and Langmuir theories. Thermal conductivity tests using the Probe Technique were carried out at 20°C on the samples again using methane as the adsorbate. The relative pressure of the methane ranged from approximately zero to 0.95. The thermal conductivity values obtained were compared and contrasted against the actual isotherms obtained at this temperature.