Abstract: In a petrochemical enterprise, the heat source for the reboiler at the bottom of the fractionation tower in the jet fuel hydrotreating unit was solely supplied by hydrotreated diesel. However, during the shutdown of the diesel hydrotreating unit, it was unable to provide heat to the bottom of the fractionation tower, resulting in substandard jet fuel product quality. Based on actual production conditions and considering factors such as equipment layout, operational flexibility, and renovation costs, the reboiler at the bottom of the fractionation tower was revamped. A double-pass horizontal thermosiphon reboiler was added, retaining the existing hydrotreated diesel heating system while incorporating a new 3.5 MPa steam supply system. After the project was put into operation, flexible switching of the heat source at the bottom of the fractionation tower was achieved by controlling the tower-top pressure and bottom temperature. This prevented daily economic losses of 2.4117 million yuan caused by the shutdown of the diesel hydrotreating unit and enabled the independent operation of the jet fuel hydrotreating unit under all working conditions.

Key words: kerosene hydrotreating unit, horizontal thermosiphon reboiler, 3.5 MPa steam, distillation column, hydrotreated diesel, jet fuel