【Daily Question】Chemical Engineering Principles 228: Distillation (November 9)
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The Chemical Engineering Theory section is launching the \"One Question per Day\" campaign starting today, aimed at helping everyone reinforce their basic knowledge of chemical engineering. Subsequent series will include those on \"Principles of Chemical Engineering\", \"Mass Transfer and Separation\", \"Thermodynamics in Chemical Engineering\", and \"Chemical Process Engineering\". We hope you will give it your active support! Answers to the questions in the \"One Question per Day\" campaign can be viewed directly by replying, and the topic will be closed after 1 day! ! Participation earns 3 wealth points, with an additional 3 wealth points for correct answers. Short answer question: What is wrong with the statement \"Distillation is based on the difference in boiling points between components\"? For systems with azeotropic compositions, there is still a difference in boiling points between components, but separation is not possible at the point where the relative volatility α = 1.
Short answer: What is wrong with the statement that “distillation operates on the basis of the difference in boiling points between components”? It is the difference in saturated vapor pressure or relative volatility
For systems with an azeotropic composition, although there are differences in boiling points among the components, they cannot be separated at a relative volatility of 1.
“What is wrong with the statement that distillation operates on the basis of the differences between components? Answer: The mistake lies in the term “boiling point differences”
“What is wrong with the statement “The distillation process is based on the difference in boiling points between components”? Answer: The error lies in the term “difference in boiling points”.
“What is wrong with the statement that \"Distillation operates on the basis of the difference in boiling points between components\"? Distillation operates on the basis of the different relative volatilities of the components.
In systems with an azeotropic composition, there is still a difference in boiling points between the components, but they cannot be separated at the relative volatility α1.
In systems with an azeotropic composition, there is still a difference in boiling points among the components, but separation is not possible at the point where the relative volatility α=1.
It should be the difference in saturated vapor pressure or relative volatility; for 95% (V) alcohol, an azeotrope is formed. Although the boiling points differ by 100 – 78 = 22 degrees, the relative volatility α = 1, making distillation-based separation impossible.
Due to differences in saturated vapor pressure or relative volatility, for azeotropes, although their boiling points differ significantly, the relative volatility α is 1, making distillation separation impossible.