Effect of pressure on distillation
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What is the effect of pressure on distillation fluctuations during distillation? This is an essay question.
Effect of pressure on distillation (generally speaking, not applicable to cryogenic air separation, etc.): 1. As the pressure increases, the relative volatility of the mixture system decreases, the driving force transmitted decreases, and the difficulty of distillation increases, and vice versa. 2. As the pressure increases, the boiling point of the material system increases, requiring higher temperature and higher grade heat sources for heating, and energy consumption increases quickly. 3. As the pressure increases, the temperature of the tower kettle increases, which may aggravate the coking and deterioration of the materials in the tower kettle, which is not conducive to the stability of product quality.
In fact, the specific pressure used is determined based on the properties of the material itself and the process requirements. This is not an absolute question.
3# 1229192020 Correct, you are right, but from an examination perspective, it can also be used as an essay question. It mainly tests the impact of pressure on distillation, that is, what impact will the appropriate change of pressure have on distillation. This kind of thinking also has a certain meaning. For example, in actual factory operations, the top discharge of a certain crude oil atmospheric pressure tower was blocked, and the operating pressure of the tower increased somewhat, which would definitely have an impact on distillation. The operating technicians have a clear understanding of this problem and can judge the impact on the separation effect.
Reducing the pressure is conducive to the distillation operation, and increasing the pressure is conducive to the absorption operation. However, for systems with small molecular weight, such as gas separation devices, due to their large gas phase load, they need to be operated under pressure.