NOVELTY - Coal raw material is pulverized. Coal tar or other adhesives are added to coal and mixed with water homogeneously. The mixture is molded into cylindrical particles and dried. The molded coal is put in a heating furnace under nitrogen protection and heated, and the temperature is maintained for 0.5-2 hours. The carbonized sample is activated with vapor under nitrogen protection. The carbonized sample is then discharged after cooling to room temperature, washing, and drying, to obtain coal-derived granular activated carbon adsorbent.    USE - Preparation of coal-derived granular activated carbon with molecular sieving effect, for use in separation of mixed gas in vacuum counter-current pressure swing adsorption to obtain concentrated and enriched product gas e.g. separation of methane and carbon dioxide from mixed gas of methane, nitrogen, carbon dioxide, and air, for industrial applications (all claimed).    ADVANTAGE - The method enables economical and environmental-friendly preparation of coal-derived granular activated carbon adsorbent having low density and high adsorption property after filling. The adsorbent enables efficient concentration of gases having different absorbability in a mixed gas.    DETAILED DESCRIPTION - Coal raw material is pulverized to 160-200 mesh. Coal tar or other adhesives are added to coal and mixed with water homogeneously. The mixture is molded into cylindrical particles having bottom diameter of 3-4 mm and a height of 5-7 mm, by using a molding machine, and then dried for 3-4 hours at 80-120 degrees C. The molded coal is put in a heating furnace under nitrogen protection and heated to 400-800 degrees C at 5-15 degrees C/minute, and the temperature is maintained for 0.5-2 hours. The carbonized sample is activated (primary activation) with vapor at 700-850 degrees C under nitrogen protection for 0.5-5 hours. The carbonized sample is then discharged after cooling to room temperature, washing, and drying, to obtain coal-derived granular activated carbon adsorbent.