FCC硫转移复合助剂的研究

Environmental concerns have resulted in legislation which places limits on the sulfur content of gasoline. However, the major source of sulfur in the gasoline pool is fluidized catalytic cracking (FCC) naphtha which usually contributes 90% of the total in China. Most economic solutions would be to use an FCC catalyst additive which could reduce the sulfur content in the FCC naphtha in situ in the cracker itself. Here a group of additives have been studied. Based on support materials as alumina and magnesium oxide, cerium and iron were added by co-gel method. The additives were blended to 8 000×10－6 with a reference FCC-catalyst. By TG analysis, it was revealed that the additive with cerium and iron would strengthen the absorption of oxygen and turn it into the oxygen in the lattice and thus make SO2 easier to be oxidized and absorbed. The results show that the extent of sulfur removal of the additive with iron for the FCC flue gas can reach up to 85.7% in a simulating device while that the reduction of sulfur for the FCC product will reach 15.8% on the base of FCC-catalyst in fixed fluidizing bed (FFB) unit. It has also been shown that the additive has no effect on the catalyst activity and the FCC product distributions.