I’ve compiled some ideas on adjusting the flash point of dry products; I hope they can be helpful to everyone

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This post was last edited by liuquan1100 on 2017-12-15 at 16:35. I. Dry point of crude gasoline (I) Main influencing factors: 1. A decrease in the top temperature of the tower results in a decrease in the dry point of crude gasoline； 2. The reaction depth increases, and the dry point of crude gasoline decreases ； 3. As the reaction pressure increases, the dry point of crude gasoline decreases ； 4. Enable cold reflux of crude gasoline, resulting in a decrease in the dry point of crude gasoline ； 5. Steam injection volume in the reaction section: at the bottom of the fractionation tower, the steam injection volume in the stripping tower is reduced, resulting in a decrease in the dry point of crude gasoline ； 6. Blockage of the trays or other factors can cause flooding, which deteriorates the distillation efficiency and raises the dry point of crude gasoline ； 7. Re-refining lightly contaminated oil and stabilizing gasoline has an impact on the dry point of gasoline. (II) Regulation methods: 1. Adjust the dry point of crude gasoline by controlling the top temperature of the fractionation tower through the flow rate and temperature of cold reflux, or the flow rate and temperature of top circulation reflux ； 2. Adjust the top temperature of the tower in a timely manner according to changes in the reaction depth; as the reaction depth increases, increase the top temperature appropriately ； 3. Control the heat distribution in the distillation tower to ensure stable operation of the tower ； 4. The dry point of crude gasoline is also related to the top pressure of the tower and the vapor-liquid partial pressure; when the top pressure and vapor-liquid partial pressure are high, or when reprocessing defective products, the top temperature should be increased appropriately. II. Control of the freezing point of cracked light oil: (I) Main influencing factors: 1. A decrease in the diesel distillation temperature in the fractionation tower leads to a reduction in the freezing point of light oil ； 2. An increase in the backflow rate to Unit 1 or a decrease in the temperature returning to the tower results in a lower freezing point of the light oil ； 3. The tower top temperature decreases, and the freezing point of light oil drops ； 4. The amount of absorbent oil returning to the tower increases, and the freezing point of light oil decreases ； 5. The properties of the crude oil become lighter, and the freezing point of the light oil decreases ； 6. Re-refining light contaminated oil has an impact on the freezing point of light oil. (II) Regulation methods: 1. Adjust the light oil freezing point by controlling the temperature of the diesel distillation tray in the fractionation tower through adjustment of the reflux flow rate and the temperature returning to the tower ； 2. When the temperature adjustment margin is limited, the flow rate between the intermediate and return streams can be adjusted appropriately ； 3. Adjust the heat balance of the distillation tower to ensure even distribution of the load across the entire tower, thereby improving the distillation efficiency. III. Control of light oil flash point (I) Main influencing factors: 1. An increase in the amount of steam used for stripping light oil raises its flash point; however, it is necessary to prevent gas blockages in the stripping tower ； 2. The liquid level in the light oil stripping tower is high, the residence time of the light oil is long, and its flash point increases. (II) Adjustment method: Adjust the amount of stripping steam based on the flash point of the light oil, in order to maintain an appropriate liquid level in the stripping tower.