Reasons for turbidity in the atmospheric, vacuum, first-stage vacuum, and second-stage vacuum lines
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Dear experts in atmospheric and vacuum distillation: We have encountered some problems with our atmospheric distillation unit. After the maintenance work in June, the atmospheric tower was restructured, which reduced the pressure drop across the trays. However, the diesel obtained from the second and third output lines has become heavier in density and is quite cloudy. Before the modifications, the Chang-2 and Chang-3 lines were relatively clear. Our current problem is that for the Chang-1 line, the removal rate has decreased compared to before the modifications, while for the Chang-3 line it’s slightly higher than before. Overall, however, the removal rate is still lower than it was prior to the modifications. What could be the reason for this? This issue has persisted for many days now, and despite trying various solutions, we haven’t been able to resolve it completely. I would appreciate any advice from those who are experts in vacuum distillation; thank you in advance.
If the outlet temperature of the furnace and the raw materials remain unchanged, adjust the distribution of the mid-stage refluxes: increase the reflux for the first stage and decrease it for the second stage.
Brother upstairs, why make such adjustments? What are the considerations behind this? Please clarify.
The yield is greatly affected by the C3 fraction; under a 95% qualification requirement, increasing the amount of C3 distillate helps to improve the yield； Reducing the secondary component level facilitates the upward movement of light components, thereby increasing the yield.
A lower pressure drop across the trays indicates that the opening ratio of those trays has increased; this can lead to a too low height of the liquid layer on the trays, increased mist entrainment, and the entry of heavier components into the second and third product streams, resulting in turbid oil products
What have you inspected, modified, and upgraded, and why was the modification made?
Yes, try making adjustments according to the parameters required for the modification; when the pressure is reduced, the area of contact between the gas and liquid phase indeed decreases.
The key is, how do you modify it? ? Was it the hole expansion or the increased tower spacing that caused the pressure drop to decrease?
What has been modified? Tell everyone to help you analyze it
I mean, what have you all changed? Please explain in detail so that everyone can analyze it