Why does an increase in reaction depth lead to a decrease in diesel pour point?
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The book says: as the reaction depth increases, the diesel freezing point decreases. Why is this?
As the reaction depth increases, the conversion rate of large-molecule hydrocarbons rises, which reduces the content of such hydrocarbons. This in turn lowers the wax content in diesel, resulting in a lower freezing point.
The reaction depth increases; large molecules undergo cleavage, and smaller molecules continue to be broken down. Difficult-to-cleave naphthenes and aromatics also begin to experience chain breaks and even partial ring opening. . . As a result, the total amount of naphthenes and aromatics in the composition of diesel gradually increases, so the freezing point decreases accordingly. . . :lol
What was said upstairs is very correct: an increase in the degree of reaction corresponds to an increased degree of cracking, which leads to an increase in the content of small molecules and a decrease in the dew point of diesel
An increase in the cyclic hydrocarbon components in the diesel composition leads to a decrease in the freezing point
So what factors are related to the freezing point?
As the reaction depth increases, the degree of fragmentation of large molecules increases; as a result, the amount of large molecules decreases while the amount of small molecules increases, and consequently the freezing point drops.
1. Raw materials... The diesel derived from paraffin-based, intermediate-base naphthenic raw materials has a progressively lower freezing point... 2. Straight-run diesel generally has a higher freezing point than diesel produced through catalytic/ coking/ thermal cracking processes... 3. Within the same distillation column, diesel with a higher boiling point has a lower freezing point; the T95 value is lower as well as the freezing point. The initial boiling point is lower (of course, the flash point must meet the required standards), and the freezing point is also lower... 4. Adding solvent oil can reduce density and freezing point... The proportion of solvent oil added must meet the minimum requirement for the flash point, which is 60 (55)...:lol
There is another reason: as the reaction depth increases, gas production rises, which leads to an increase in the pressure in the settler and the fractionation tower; in other words, the partial pressure of oil and gas increases. Therefore, under unchanged other conditions, the dew point of diesel decreases.
Can it be assumed that macromolecules are the heavy components, while small molecules are the light components? As the reaction depth increases, with more small molecules = lighter components, does the freezing point decrease?
How did I read in a book that an increase in aromatic compounds leads to an increase in the specific gravity of oils?
As the depth increases, the proportion of light components in diesel rises!
As the reaction depth increases, the conversion rate of light hydrocarbons rises; more large molecules undergo recombination and fragmentation, resulting in an increase in the content of light hydrocarbons. There are more light components in diesel, which leads to a decrease in its freezing point and a reduction in its flash point!
As the depth increases and long chains break down into shorter chains, the freezing point decreases