The Study Of The Preparation Of Carbon Molecular Sieve From Coking Process Surplus Sludge For Air Separation

The carbon molecular sieve (Carbon molecular sieve, CMS).is a kind of product, which has highly effective gas separation properties for rich nitrogen from air, there is a widespread using value in metallurgy industry, chemical process environmental protect, and food industry. The surplus sludge of the coking plant was used as the raw material, through adding coal tar pitch and high temperature coal tar and so on, through mixing, extrusion molding, carbonization and micropore modify technological process to prepare the granular carbon molecular sieveThe influence of carbonization condition, the chemical additive type and the addition quantity, the condition of the liquid phase impregnation as well as the chemical vapor deposition and so on to the air separation performance of the CMS was studied. The experiment result indicated that the best carbonization condition was the heat treatment at 750℃for 40 min with heating rate 6℃/min, under this condition the CMS had better ability of air separation (the N₂ can be enriched to 86.49%). When the addition of the amylum and the medium temperature pitch is 15% and 10% respectively, and CMS prepared in this condition had better ability of air separation, the N₂ can be enriched to 90.48%. The method of dipping the high temperature coal-tar oil and benzene solution may effectively enhance CMS to the air separation. The result indicated as dipping time was 3h, the concentration of dipping liquid was 3%, and heating temperature at 750℃, was the effective way to improve the ability of CMS for air separation. And N₂ can be enrich to 92.78%.Simultaneity on this basis for improving the capability of CMS for air separation, the method of chemical vapor deposition was used, the dosage of benzene, heating temperature, and heating time influence on CMS's capability for air separation were investigated. The result of experiment indicate the dosage of benzene at 6% equal to CMS quality, heating treatment at 750℃for 1h, this coke deposition was an effective way to modify the micropore structure of CMS, N₂ can enrich to 95.23%.Then the method of doing chemical vapor deposition, which leads to a bit of H₂ was used and the effect of in H₂/N₂ atmosphere for chemical vapor deposition on controlling the pore size of CMS for air separation was discussed. When the impregnating method was used, i.e. impregnating different pore size of CMS with FeSO₄·7H₂O 5wt% solution, calcinating the sample in N₂ and reducing the loaded iron species in H₂/N₂, to the desired state Fe₃O₄, the air separation ability improvement was investigated.