Issues related to improving the yield of light oil from catalytic cracking? (Searching for oneself)
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I would like to ask the experts: what are the factors that affect the light oil yield in catalytic cracking units? What measures can improve the yield of light oil? What are also the crude oil compositions of these various units, and what is the light oil yield?
In my opinion, the main factors affecting the light oil yield (gasoline + diesel) in catalytic cracking units are as follows: 1. Unit design – there are many different types within the catalytic cracking family, and the light oil yields vary significantly among them; 2. Nature of the feedstock – there is a significant difference between catalytic cracking of residue mixed with oil and that of ordinary distillate oils； 3. Catalyst performance, especially activity and selectivity ； 4. Selection of reaction conditions, especially reaction depth.
This post was last edited by dongliangsir on 2010-5-23 at 17:36. Dear friend looking for oneself: Due to my mistake, I deleted your original post earlier (I intended to delete only the replies). Since it’s not possible to restore it, I had to repost the original content. Please reply below, and I will rate your response again. I apologize once again for any inconvenience this may have caused you. dongliangsir 2010-5-23
Hehe, it’s fine, fine – as long as we figure out the problem
The light oil yield of the catalytic unit is the sum of the gasoline and diesel yields, and its level depends on the type of unit, the properties of the feed oil, the activity of the catalyst, and the conditions of the cracking reaction. Common methods for controlling the light oil yield include reaction temperature (appropriate reagent-to-oil ratio), reprocessing ratio, and catalyst activity. Generally speaking, a higher reaction temperature, a lower reprocessing ratio, and higher catalyst activity can increase the gasoline yield ； A low reaction temperature, a high recycle ratio, and low catalyst activity can increase the diesel yield. During the production process, it is necessary to maximize the sum of the yields of these two, and an optimal balance point should be sought. Composition of raw materials for our device (design data): straight-run wax oil 57.5% + hydrogenated wax oil 30% + (vacuum residue and reduced four-line oil) 12.5% ； Light oil yield: 63.8%.
While ensuring that the two key parameters of diesel, namely its pour point and flash point, remain within acceptable limits, it is possible to increase diesel production by lowering the initial boiling point of diesel and the dry point of gasoline, as well as by raising the dry point of diesel itself. First, reduce the bottom temperature of the splitter tower to lower the dry point of gasoline. Second, increase the diesel extraction temperature and the first intermediate extraction temperature. Third, optimize the amount of gas vapor in the diesel stripping tower. Fourth, expand diesel fractions.
The selection of a catalyst is very important; if a catalyst is not suitable for the type of oil, it will be difficult to meet the requirements