Abstract: The difficulties existing in the process of producing ultra-low sulfur clean diesel and their effects on the economic benefit and long-term operation of the refinery were analyzed for improving the flexibility of optimizing and adjusting the production plan of the whole plant. On this basis, through a series of measures, such as adjusting the diesel cutting point of delayed coking unit, optimizing the feedstock ratio of diesel hydrotreating unit, reducing the output of FCC slurry, adjusting the load of VGO hydrotreating unit and hydrocracking unit, optimizing the operation of atmospheric and vacuum furnaces, etc., the service life of catalyst in the diesel hydrotreating unit was prolonged to over four years. By calculation, the total output of gasoline could be increased by 107 kt/a, the fuel gas could be saved by 1 200 t/a, and the hydrogen consumption could be reduced by 1 500 m³/h.

Key words: ultra-low sulfur diesel, production plan, optimization, crude distillation, fluid catalytic cracking