Why is the dry point of the naphtha produced by diesel hydrogenation different from the initial boiling point of the diesel?
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According to the analysis results, the dry point of naphtha is 153, and the initial boiling point of diesel is 176; so what is the boiling range for those temperatures between them, which is over 20 degrees? Please help! ! ! I beg! !
Is it because the boiling range of naphtha is narrow? ?
Generally, naphtha (boiling range 35–205°C) consists of C-5 to C-11 compounds, while diesel (boiling range 200–350°C) consists of C-11 to C-20 compounds. At temperatures between 150 and 200°C, the compounds are C-8 to C-11 (based on personal experience). Does hydrogenation of diesel not produce C-8 and C-9 compounds? Or did it undergo a secondary reaction and turn into something else? (For reference only)
This is mainly related to the raw materials; if there are few components within that specific boiling range in the raw materials, then the reaction products will also hardly contain such components.
Diesel hydrogenation generally involves mainly refining reactions, with a small amount of cracking reactions as well. If there is already little C8-C11 in the raw material, the same will be true for the reaction products. In hydrocracking, the product distribution is relatively wide.
This condition is called fractional vacuuming. In other words, in two adjacent fractions, the final boiling point of the lighter fraction is lower than the initial boiling point of the heavier fraction. The greater the degree of vacuum, the better the fractionation effect; this does not mean that there are no components within that boiling range in the feedstock, but rather it is due to the higher fractionation precision of the distillation column compared to the Enthropic distillation process.