Function of the pre-distillation tower in gasoline hydrogenation
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This post was last edited by linweihua6 on 2011-9-13 08:23. There is a pre-distillation tower before gasoline hydrogenation; the light fractions at the top of this tower are not subjected to hydrogenation. I would like to know why this is the case, and what use these fractions have What are its main components? Won’t it go bad?
It ensures the octane rating of the refined gasoline; since this type of gasoline has a high content of olefins, which gives it a high octane rating, as well as a low sulfur content. If it enters the subsequent reactor beds, it can cause overheating in those beds, and it will also lead to significant saturation of the olefins, thereby drastically reducing the octane rating
The relatively light components in gasoline contain more olefins, resulting in a relatively higher octane rating. Additionally, they have a low sulfur content, which makes it easy to remove sulfur. The purpose of this is to separate out the light components; desulfurization can be achieved through simple alkaline treatment. Moreover, since the olefins do not undergo hydrogenation, they do not experience saturation reactions, allowing the product to maintain a high octane rating. This portion of gasoline is ultimately mixed with hydrogenated heavy gasoline to form a gasoline product that is then released for sale. The common cutting temperature is 90 degrees, though it may vary slightly depending on the actual properties of the raw materials, sometimes being considerably lower. I can’t figure out why it went bad...
I agree with the view from the second floor: if all the oil were hydrogenated, its octane rating would drop. Therefore, some oils with high octane ratings and low sulfur content do not need to be hydrogenated; instead, they require desulfurization. In the end, it’s sufficient to ensure that the total sulfur content in the blended gasoline is below the specified limit!
Its purpose is to reduce octane loss; that’s all
A pre-distillation tower is used to separate gasoline into light and heavy fractions, typically in a 4:6 ratio. The light fraction is directly desulfurized, while the heavy fraction is hydrogenated first before being desulfurized.
Light gasoline can be subjected to desulfurization treatment
What those upstairs have said is mostly correct. Pre-fractionation is primarily used to separate different fractions of components, ensuring that heavy components, after hydrogenation, do not cause an excessive rise in temperature in the catalyst bed due to the exothermic reaction of olefin saturation; it also helps to remove some water. In secondary oil processing, the sulfur content of oil increases gradually as the temperature rises. The sulfur content in the light gasoline at the top of the tower is low, so hydrogenation is not necessary. It is also necessary to maintain a certain level of olefins in the light gasoline, as it is the olefins that contribute to increasing the octane rating of the gasoline. Octane number: Aromatics > Alkenes > Alkanes
How can I set up the distillation column in the simulation to ensure that the yields of light and heavy gasoline reach 99.6 wt%?