Regarding the handling of excessively high tower pressure in the reformation distillation column.
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I graduated from university in 2015 and am currently working at a catalytic reforming unit in a petrochemical company; I’m feeling quite lost at the moment. For example, yesterday the pressure in the stabilizer tower (fractionation tower) was too high; the technician instructed that the reflux rate be reduced. I just couldn’t understand why – if the reflux rate is decreased, shouldn’t the pressure at the top of the tower increase instead? Wouldn’t that mean more material would flow upward? But the fact is that as the temperature at the top of the tower rises, the amount of dry gas in the reflux tank drops immediately. Help!!! The problem might be pretty stupid; please don’t criticize me
Let’s see what it says in the principles of chemical engineering
With excessive reflux flow, the vapor load at the top of the tower definitely increases, and thus the tower pressure rises as well.
The reflux at the top of the tower consists of light components; a large amount of reflux means a high vapor load, and thus a high tower pressure is necessary
Well, the reflux consists of light components; the more there is of it, the greater the overhead vapor load, and consequently the tower pressure increases.
The more reflux, the lower the tower top temperature
The cooling load at the top of the tower is too high; as a result, the reflux components cannot settle and continue to circulate inside the tower. Over time, more and more of these components accumulate there, and they end up being carried away with the dry gas. The correct approach is to reduce the temperature at the bottom of the tower as well as the amount of reflux.
The large backflow volume results in a higher amount of light components inside the tower, while the heat absorption and temperature rise cause the components at the top of the tower to be lighter in nature with relatively high pressure