Preparation Of Carbon Molecular Sieves For Air Separation By Pressure Swing Adsorption

In this paper, Carbon molecular sieves (CMS) were produced from petroleum coke and phenolic resin.Usually, it is difficult to prepare CMS suitable for air separation from petroleum coke directly because of its compact structure of the crystal lattice and high ratio of C/H. Preoxidation, intercalation and mechanical grinding are involved to change the microstructure of petroleum coke. The micropore volume of CMS made from preoxidized coke is increased as well as ability of air separation. Especially the CMS obtained from coke oxidized by HNO3 can enrich N₂ to 93% in PSA. The interlayer spacing d₀₀₂ of the petroleum coke is increased after intercalated by H₂O₂ and H₂SO₄, which contributes to porosity development of CMS. As a result, N₂ can be concentrated to 93% in PSA by the CMS prepared from the petroleum coke intercalated by H₂SO₄ and H₂O₂ in a ratio of 20:1 (V/V) for 60 minutes. It indicates that the ability of air separation of the CMS can be enhanced by mechanically grinding of petroleum coke for a long time. N₂ can be enriched from 90.2% to 92.5% in PSA by the CMS by grinding the petroleum coke from 20h to 1 OOh.A super performance of air separation of the CMS synthesized from phenolic resin can be obtained. Ability of air separation of the CMS (CMS-A) from the phenolic resin is comparable with that of CMS (CMS-B) from Germany, N₂ could be concentrated to 98.6% of CMS-A and 98.7% of CMS-B with a flow of product gas 200L/(kg.h) in PSA...