Inverted temperature in the pre-distillation column
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Methanol distillation: Our plant uses three-column distillation, with the temperature at the top of the column being higher than that at the bottom. A possible reason for this is the addition of water to the pre-condenser reflux tank; why does adding water to the reflux tank result in a higher temperature at the top of the column compared to the bottom?
The occurrence of temperature inversion indicates high moisture levels at the top. Because water has a higher boiling point than methanol at the same pressure.
Another possibility is that the non-condensable gas at the top of the tower was not discharged after driving the machine
It’s true that the boiling point of water is higher than that of methanol, but to raise the temperature of water from over 60 degrees to 80 or 90 degrees, where does the heat come from? The heat at over 60 degrees from methanol cannot be transferred to water either
The heat comes from the bottom of the tower. Since both methanol and water at the top of the tower exist in gaseous form, with a higher proportion of water and a lower proportion of methanol, the boiling point of this mixture tends to be higher than that of methanol alone. As a result, the temperature at this pressure is higher than normal. The simplest way to understand it is that a high temperature at the top of the tower indicates that the product is substandard, meaning it contains too much moisture! When it reaches a certain level, temperature inversion occurs!
What about the changes in pressure? Should we consider the gauge issue?:):)
The non-condensable gas at the top of the tower was not released, resulting in poor mass transfer.