The invention relates to a preparation method and use of a carbon
molecular sieve. The preparation method comprises the following steps: preparing a conventional carbon
molecular sieve; and expanding the pores in the conventional carbon
molecular sieve by using a secondary
activation technique and modifying the conventional carbon molecular
sieve by adjusting the pores. The new carbon molecular
sieve is prepared by using
coal, coconut shell or phenolic resin, and the like as raw materials, by the conventional production steps of crushing, forming, carbonizing, steam activating,
hydrocarbon settling and shrinking and the like and by secondary activation with KOH or CO2 as an activator. The
activation temperature is between 550 and 850 DEG C; and the ignition
loss rate of the product is kept be between 0.1 and 30 percent. In aspect of use, the carbon molecular
sieve can be used for absorbing
nitrogen molecules and can also be used for absorbing and separating
methane and
nitrogen in seam gas under a
variable pressure while achieving an adsorption dynamic separation effect and allowing high-concentration
methane gas to be collected at the exit of an adsorption
tower directly; and thus, the
methane in the seam gas can be used efficiently.