How does the tower temperature change when the pressure at the top of the distillation tower changes?
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It refers to the change in temperature when the tower pressure changes, with all other conditions (such as steam volume, reflux, etc.) remaining unchanged We usually say that pressure increases temperature and boiling point (due to the rise in boiling point), but under pressure the components in a vaporized substance become lighter, while temperature reflects the properties of the material components; therefore, the temperature should decrease! Seeking advice from experts
Undoubtedly, as pressure increases, temperature must also increase. There are two reasons for this: (1) Pressure, composition, and temperature are in a one-to-one relationship; as pressure increases, if the composition remains unchanged, then the temperature must rise. (2) What is the basis for separation in a distillation system? Relative volatility between components. The greater the relative volatility, the easier the separation. The relative volatility generally varies inversely with system pressure; the higher the pressure, the lower the relative volatility. Therefore, under the same conditions of reflux and steam volume, the heavier components in the system will definitely move upward, and the temperature will still rise. So, whether from the very beginning or based on subsequent trends, as a result of increasing pressure, the temperature also rises~
I don’t understand what temperature is being referred to? After the tower pressure increases, the evaporation rate at the bottom of the tower decreases while the amount of steam used for heating remains unchanged. Under the gas-liquid equilibrium condition within the tower, the concentration of heavier components at the top of the tower decreases, yet the flow rate of material returning to the top of the tower stays the same; in other words, the heat absorbed remains unchanged. Does this mean that the temperature at the top of the tower rises? Should it still go down?