An FCC Catalyst for Maximizing Gasoline Yield

A Y zeolite-containing wide-pore composite was synthesized by in situ technique using polyvinyl alcohol and silica sol material. A fluid catalytic cracking (FCC) catalyst for maximizing gasoline yield was successfully developed with the modified composition. The as-made zeolite Y in its sodium form had a relative crystallinity of 52.9 % with a high silica/alumina amount of substance ratio of 5.7. The FTIR analysis showed that the acid distribution of the catalyst modified with rare earth, phosphorus and steaming stabilization process was more concentrated on the range of intermediate and strong acidity. This kind of modification can direct more hydrocarbons to enter into the pores to be converted, as well as remarkably increases the possibility of gasoline formation through a cracking reaction. The nitrogen adsorption–desorption analysis showed that the catalyst had more mesoand macro-pores distribution, which can effectively reduce the mass-transfer resistance in the reaction process and accelerate the diffusion of the product molecules. The evaluated results indicated that the prepared catalyst could decrease the excessive cracking of middle distillate and improve the gasoline yield effectively. The gasoline yield by mass had increased by 2.69 %, while the coke yield and dry gas yield had decreased by 0.91 % and 0.19 %, respectively, and then the olefin content by volume in the cracked gasoline reduced by 4.6 %, the research octane number (RON) and motor octane number (MON) increased by 0.6 and 0.5, respectively. The good product selectivity and higher gasoline yields of the prepared catalyst were obviously related to its wide pore structure and its optimized acidity distribution.