Operation of the fractionation tower
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Have you all encountered this problem: the dry point of the product at the top of the distillation column exceeds the specified limit, meaning that the composition is too heavy, while the flash point of the product at the bottom of the column is close to the upper limit for flash points, i.e., it is on the lighter side within the normal range. How does everyone handle this situation?
Possible cause: The reflux ratio of the tower is low. Low temperature of raw materials entering the tower (temperature at the furnace outlet); problems with the trays inside the tower, such as flooding or other issues; insufficient stripping steam at the bottom of the tower.
If the inlet temperature of the tower increases, wouldn’t that lead to an increase in the content of heavy components at the top of the tower? Similarly, an increase in the amount of gas vapor also results in heavier components at the top of the tower. Aren’t these two situations contradictory?
There is a high possibility of the tray being overturned, or the operating load is too high!
Agree with what was said above; it’s possible there is a problem with the tray, the tray may have fallen off, or the floating valve may have come loose
It happens occasionally, not frequently, and the operational load of the device is within the normal range
The distillation column has numerous trays from bottom to top; the components at the bottom of the column are lighter, so the inlet temperature can be increased. The components at the top of the column are heavier, so the temperature at the bottom of the column can be reduced, which means increasing the reflux. You might think there is an interaction, but there are intermediate products in the middle of the tower, so no need to worry! For reference only
So, what is the relationship between the control of the temperature at the bottom of the tower and the control of the feed temperature?