Generally speaking, the adjustment methods for unqualified products at the bottom of the tower

Generally, if the quality of the product at the bottom of the tower is unqualified, it is because the content of light components exceeds the standard. The temperature at the bottom of the tower can be appropriately increased (the load heat of the reboiler must increase), and the reflux should be increased at the same time. Pay attention to keeping the temperature and pressure at the top of the tower stable, and pay attention to the liquid level at the bottom of the tower not to be evacuated. Generally, do not adjust the feed amount, otherwise it will easily lead to unstable tower operation.

If the quality of the product at the bottom of the tower is unqualified, it is usually because the light component content of the tower kettle exceeds the standard. The temperature of the tower kettle can be appropriately increased, that is, the steam volume of the reboiler can be increased, and the reflux flow rate can be appropriately increased. Under normal circumstances, the feed amount is not adjusted, and the feed composition can be sampled and analyzed to compare with the normal data. Sometimes, if the feed composition changes, the operating parameters of the tower are not adjusted in time, which will also affect the product quality.

1. If the accuracy of the top product is too high and there are multiple feeding positions, the feeding position can be appropriately raised. 2. Increase steam load and return flow. 3. There is no direct relationship between the feed amount and product quality, but there may be an indirect relationship. For example, when the feed amount is not within the optimal operating area of ​​the tray, adjusting the feed amount may improve the distribution of liquid in the tower. When it can improve the efficiency of the tray, adjustments can also be made. 4. If the above is invalid, you can only replace the high-efficiency tray or heighten the tower body.

1. The top extraction is too small, increase the top discharge. 2. The feed amount is too large, reduce the feed amount. 3. The tower kettle temperature is too low, increase the tower kettle temperature.

Points 2 and 3 are understandable. As for point 1, have you done this on site? ? To what extent can it be adjusted?

The information you provided is relatively small, so there are many options available.: 1. It is feasible to increase the extraction at the top of the tower, but the prerequisite is that the materials at the top of the tower must meet the index requirements or be higher than the index requirements. It can be understood this way: Under the condition of a certain feed, if less light components are extracted from the top of the tower, more light components will accumulate in the tower still, and the tower will be unqualified. At this time, the tower top extraction should be appropriately increased (the reflux will be reduced). If the top material is still qualified after increasing the tower top extraction without increasing the heating of the tower kettle, it is said that this operation is correct. On the contrary, this method cannot be used. 2. Decreasing the feed amount can also be considered as a relative increase in tower top extraction, but the reflux ratio at this time has not changed, and the top material will generally not exceed the standard (provided that the feed reduction is appropriate). 3. If the top and bottom materials are not up to standard, it is necessary to increase the evaporation volume of the tower still, increase the reflux, and adjust the top extraction volume. In short, it cannot be explained clearly in one or two sentences. It needs to be adjusted on the spot. One method may be used, or multiple methods may be used.

There are many types of unqualified products at the bottom of the tower. For example, the content of light components is high, it contains other components, the distillation range does not meet the requirements, etc. If the light component content exceeds the standard, adjust the: 1. Increase the heat load at the bottom of the tower ； 2. Reduce tower top reflux ； 3. Reduce feed ； 4. If the tower has multiple feed inlets, the feed position can be raised and the height of the stripping section can be increased.

Very well explained, I understand. Thanks!

The unqualified product at the bottom of the tower is that there are many light components in it. We only need to pull out the light components to solve the problem! Go down from the top of the tower: 1. You can reduce the pressure at the top of the tower 2. Reduce the reflux volume at the top of the tower 3. Reduce the reflux volume in each middle section 4. Open the side line extraction appropriately 5. Increase the feed temperature 6. With stripping, the amount of stripping steam can be increased, and with a heating furnace at the bottom of the tower, the return temperature can be increased.