Abstract: The effect of recycling hydrogenated LCO, RLG diesel and kerosene fractions in catalytic cracking unit through LTAG (LCO to aromatics and gasoline) nozzles were analyzed in terms of improving the structure of refinery products and reducing the ratio of diesel to gasoline. The LTAG nozzles in FCC unit were used to reprocess hydrogenated LCO, which improved gasoline yield while increasing the production of vehicle diesel. The combination of LTAG process and RLG process in FCC unit could greatly reduce the output of diesel, decrease the ratio of diesel to gasoline, and increase the yield of light oil and economic benefit by recycling RLG diesel. At the same time, when the catalytic cracking unit recycled the kerosene fractions, more gasoline and LPG could be produced,thus improving the product structure, optimizing the product distribution,which could solve the market problem of jet fuel.

Key words: catalytic cracking, LTAG, nozzle, LCO, jet fuel fraction