Is the alkylation dehydrogenation tower not separating well? ? ? ? ?
Thread Content
The packing column in the fourth section of the company’s dehydrogenation tower is not performing well in terms of separation; C4 is present at the top while C3 is present at the bottom. The current pressure in the tower is 14 kilograms, and the temperature of the gas at the top of the tower after cooling is around 40 degrees. Under normal conditions, the difference between the temperature of the gas stream returning to the tower at the bottom and the temperature of the packing in the fourth section was only 2 or 3 degrees, but now it is over 7 degrees. The bottom temperature of the tower doesn’t rise, while the top temperature keeps increasing; it always seems like there’s a problem inside the tower. C3 is likely to have to stop due to poor control! ! ! ! !
Yes, the C3 at the bottom of the tower can’t be controlled, so the alkylation reaction can’t proceed. Start your search from the following aspects: 1. The C3 component in the raw materials is high, or there are other light components present. It is recommended to conduct tests for carbon dioxide and nitrogen. 2. The cooling water temperature is high, and the temperature of the return fluid is high. 3. The trays have suffered corrosion due to long-term use; it is recommended to replace them.
The same situation existed before shutdown in May; after shutting down for maintenance, the tower was subjected to steam cleaning. The manager went up to check and said that the packing was fine. Well, before restarting in June the flow rate was low and there were no problems, but now that the flow rate has increased, the same old issue has arisen. During the shutdown and material removal process, water was used to flush the carbon four feed pump, and as a result, a large amount of water ended up in the reflux tank while very little reached the bottom of the tower
It’s probably a problem with the raw materials; the content of terpenes is too high
Raising the bottom temperature alone doesn’t work; adding water to the reboiler also has no effect. As the bottom temperature increases, the top pressure rises as well. If the reflux is reduced, isobutane at the tower top rises to levels of 7 or 8, while there is still a large amount of propane at the tower bottom.
Is the reflux temperature important? The cooling water pressure has decreased by 0.03 MPa compared to before, but it probably doesn’t have much impact on the return temperature