Abstract: Due to the presence of water in diesel from the 1.5 Mt/a diesel hydroupgrading unit of a petrochemical company, the increase of process load and the sales of diesel fuel product are seriously restricted. In order to solve this problem, the cause of turbidityin diesel was analyzed in detail, and the industrial salt dehydration system and high efficiency coalescence dehydration system were designed and installed. The application results showed that the water mass fraction in diesel was reduced to 58—311 μg/g after the industrial salt dehydration process and 96.5—109 μg/g after the high-efficiency coalescer dehydration process, with the water removal rates higher than 78% and 93%, respectively. Both processes showed good dehydration effect for diesel fraction, in which the coalescer dehydration process was better. According to the seasonal characteristics of diesel production, the combination of the two processes can be used to ensure the water content and appearance of diesel product.

Key words: hydroupgrading, diesel, fog, dehydration, coalescer