In fact, it is also an activated carbon, which is different from the carbonaceous adsorbents in general in that the micropore diameter is evenly distributed in a narrow range, the micropore size is equal to the diameter of the gas molecules to be separated, the micropores The specific surface area generally accounts for more than 90% of the total surface area of carbon molecular sieve. The pore structure of the carbon molecular sieve is mainly distributed in the form of: the diameter of the macropore is communicated with the outer surface of the carbon particle, the transition pore is branched from the macropore, and the micropore is branched off from the transition pore. In the separation process, macropores play the role of transport channel, micropores play the role of molecular sieve.
Carbonaceous carbonaceous method, gas activation method, carbon deposition method and impregnation method are used to produce carbon molecular sieve from coal. Among them, the carbonization method is the simplest, but several methods must be used in combination to produce high quality carbon molecular sieve.
Carbon molecular sieves have been successful in the field of air separation for the production of nitrogen and have broad prospects for other gas separations.