Production, characterization and applications of carbon molecular sieves from a high ash Greek lignite

Activated carbons were produced from raw and demineralized Creek lignite un der various experimental conditions. Demineralization was accomplished by a cid washing of raw lignite, and pore structure of products was estimated by adsorption of N-2 at 77K and of CO2 at 298K. Demineralization caused a dec rease in coal reactivity but the activated products had a high surface area . Activated carbons produced from demineralized lignite at low burn-off wer e exclusively microporous, and had significant molecular sieving properties to gases, as derived from the uptake curves of CO2, CH4, O-2 and N-2 at ro om temperature. Carbon molecular sieves were also produced from activated c arbons containing the ash minerals, by employing a method of propylene crac king for coke deposition and pore structure modification. High reaction tem peratures resulted in a decrease of the mesopore surface area while the mic ropore surface area was unchanged. Samples prepared under these conditions had high CO2/CH4 selectivity ratios, exhibiting molecular sieving behavior for gas separations.