Selective Hydrogen Transfer Reaction in FCC Process: Characterization and Application

The product distribution and gasoline quality of FCC process, especially the olefin content, heavily depended on the catalyst performance in terms of selective/non-selective hydrogen transfer reaction selectivity. A novel experimental method was established using n-dodecane as the feed to characterize more precisely the selective hydrogen transfer (SHT) ability of catalytic materials. The catalyst CRC-1 showed the highest HTI values (the yield ratio of products C₄ paraffin to C₄ olefins), and the catalyst ZCM-7 exhibited the lowest HTI among the tested catalysts. The catalyst GOR-I deactivated faster than GOR-II, which is the second-generation catalyst for gasoline olefin reduction with a major improvement in coke selectivity while maintaining high olefin reduction ability. The values of SHT and non-selective hydrogen transfer (NSHT) reactions differed significantly for different catalysts. The major zeolite component in CRC-1 catalyst was REY with very high acid site density, which could effectively promote both NST and NHST. Catalyst ZCM-7 exhibited poor performance in gasoline olefin reduction, which is also in agreement with the results of n-dodecane cracking reaction.