Problems with catalytic cracking light diesel

1. What does the freezing point of catalytic cracking light diesel depend on? Related to the C5 and C6 content in light diesel ； High, low freezing point, low content; high freezing point. 2. If, due to equipment failure, the amount of diesel extracted from the distillation tower is reduced temporarily (for 3–4 hours) or even comes to zero, with no significant changes in other conditions, what impacts will this have on the quality of gasoline and diesel? It will cause the final boiling point of gasoline to increase and the initial boiling point of diesel to decrease, resulting in substandard products.

1. After considering the factors that affect diesel freezing point, the most important determinant is the raw material – as the saying goes, “a dragon gives birth to dragons, and a phoenix gives birth to phoenixes”; it’s the same principle here. 1) Among the components of diesel, alkanes generally constitute the largest proportion, followed by naphthenes, and then aromatics. Changes in the ratio of naphthenes to aromatics have a greater impact on the freezing point compared to changes in the alkanes content; the higher this combined ratio, the lower the freezing point. This is a general rule, though there are currently no direct data to quantify this relationship... 2) The upper portion of diesel corresponds to the lower portion of gasoline, while the lower portion of diesel corresponds to the upper portion of reprocessed oil. This characteristic can be utilized to adjust the freezing point when modifying the composition and boiling range of diesel... The more C9-12 components present, the lower the freezing point; the more components with a T95 value above 350, the higher the freezing point... 3) For crude oils with a similar boiling range, the freezing points of straight-run diesel, catalyzed diesel, and coked diesel decrease in that order... 2. Whether due to equipment failures or other reasons that prevent diesel from being extracted from the tower, theoretically, it has no effect on the overall heat supply and removal within the tower, nor on the material balance (meaning that gasoline is still separated at 205 degrees). However, the tower will need to redistribute the energy and mass flow for the entire diesel fraction across each theoretical tray. In other words, the failure to extract diesel has no impact on the quality of the top and bottom products of the tower (as both gasoline at the top and the oil slurry at the bottom must meet specified separation requirements). Diesel is a side product, and its extraction can be controlled on or off... :lol Last edited by wangsc on 2009-2-11 18:49]

"Since the diesel is not extracted, it has no impact on the quality of either the top product or the bottom product. So where does that diesel component go?