PETR 75 |
| The reaction mechanisms for conversion of the large S- and N-compounds found in VGO FCC-feedstock into the smaller organic S- and N-compounds found in FCC-gasoline and other FCC-products were examined. The studies were performed under realistic conditions in an FCC pilot plant with circulating catalyst. It was found that the S-compounds in FCC-gasoline, i.e. thiophenes/benzothiophenes, were formed from recombination reactions between hydrogensulphide and olefins generated in the FCC-unit. Similarly, the N-compounds found in the FCC-gasoline, i.e. anilines/indoles, were formed from recombination reactions between ammonia and olefins. These results explain the fact that the S/N-compounds in FCC-gasoline are mostly the same species with only minor differences in the relative concentration of the individual compounds. This phenomenon is not dependent on the feed charged to the FCC-unit but is a result of a thermodynamically controlled equilibrium between olefins, H2S and ammonia, respectively, and the temperature in the FCC reactor. |
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7th International Symposium on Advances in Fluid Cracking Catalysts (FCCs)
8:30 AM-11:50 AM, Tuesday, 12 September 2006 Palace -- Telegraph Hill, Oral
Division of Petroleum Chemistry |