Please help me answer a question
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In a distillation column, with all other conditions remaining unchanged, if the column pressure is increased while simultaneously reducing the reflux rate to maintain the temperature at the top of the column at the same level as before the pressure increase, how will the composition of the material at the top of this distillation column change?
Increasing pressure reduces the load, while decreasing backflow increases it; it’s hard to say what happens when both are considered together
The key is to maintain the original top temperature; as pressure increases, the boiling point rises, and the concentration of light components should increase.
What was said upstairs makes sense; the proportion of light components will be a bit higher~
An increase in column pressure raises the top temperature of the column, and reducing the reflux also raises the top temperature. How can the temperature before pressurization be maintained?
Both raising and lowering the reflux tower top temperature will cause it to rise.
1. In positive-pressure distillation, as the pressure increases, the relative volatility rises; in other words, the boiling point of the mixture increases, making it more difficult to vaporize. As a result, the top temperature should rise, and backflow should be reduced. Wouldn’t that lead to an even higher top temperature? It becomes difficult to determine the composition of the mixture under such conditions. If the reflux is increased while maintaining the original temperature, then the amount of light components at the top of the tower will definitely decrease. 2. In the case of vacuum distillation, in our system, if the original temperature is maintained and the reflux is increased, then the amount of light components will decrease, while the amount of heavy components will increase. Once the pressure rises to a certain level, the product quality is affected and the distillation system can no longer operate.