Questions about the feed port of the distillation tower
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On which tray should the feed port of the methanol distillation tower be opened? On what basis should we judge whether it is reasonable? Let’s discuss it.
It should be the material composition calculated based on the gas-liquid balance of each tray in the distillation tower under the design conditions, and be selected on the tray closest to the composition and state of the feed.
This is mainly based on the feed composition of each tower to determine the position of the feed port. The closer the feed material composition is to the material composition on which tray, the better the opening is. On the other hand, based on your needs for the product, whether your product is a light component or a heavy component in the entire material composition, for different positions of the tower, decide whether there are more trays in the rectification section or more trays in the stripping section, and then determine the appropriate feed position.
The number of feed trays is determined based on the material composition of each tray in the methanol distillation tower when the gas-liquid balance is reached. The principle of determination is that the material composition at the time of feeding is more* * The better the material composition is when measured.
Usually there are three feed inlets of the distillation tower, which are installed at different heights of the tower. During production, the appropriate feed port should be selected according to the specific conditions, and adjustments must be made if necessary. According to the meaning of the optimal feed plate position, it can be seen that for a rectification tower where the material temperature is at or near the bubble point, the selection of the feed port is determined based on the composition of the feed and the composition of the feed plate. Generally speaking, when the volatile components in the separated mixture increase, a higher feed port is selected to increase the number of plates in the stripping section. ； Otherwise, use a lower feed port. When the feeding status changes, the feed port should be adjusted accordingly. When the feed temperature decreases, use a higher feed port; otherwise, use a lower feed port.
Changes in feed composition directly affect the distillation operation. When the concentration of heavy components in the feed increases, the load on the distillation section increases. For a tower with a fixed number of plates in the distillation section, heavy components will be brought to the top of the tower, making the quality of the top product unqualified. When the feed composition changes, the feed port can be changed: When the components become heavier, the feed port is moved downwards. ； When the components become lighter, the feed port is moved upward.
Changes in feed composition directly affect the distillation operation. When the concentration of heavy components in the feed increases, the load on the distillation section increases. For a tower with a fixed number of plates in the distillation section, heavy components will be brought to the top of the tower, making the quality of the top product unqualified. When the feed composition changes, the feed port can be changed: When the components become heavier, the feed port is moved downwards. ； When the components become lighter, the feed port is moved upward.
Theoretically, it is related to the design of the tower itself. Generally, based on the design conditions of the tower, it is calculated that the material on that layer of pedals is similar to the coarse material, and the material is fed on this layer.
In theory, the selection of the feed plate is the one closest to the selected components. In actual operation, it is necessary to look at several aspects: 1. Look at the feed temperature and select a tray that is close to the feed temperature. 2. Look at the changes in components. If there are more light components at the bottom of the tower, move the feed plate up. If there are more components at the top of the tower, move the feed plate down. 3. Except for towers that are relatively small and difficult to stabilize and have large fluctuations, the position of the feed plate is generally rarely moved. 4. You can still consider it. They are all a bit open.