This x versus y curve is called 45 o line x y Equilibrium line Fundamentals

This x versus y curve is called 45 o line x y

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This x versus y curve is called 45 o line (x = y) Equilibrium line
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Fundamentals & Principles of Distillation Relative Volatility (α) Relative volatility is a very convenient measure of the ease or difficulty of separation in distillation. The volatility of component a relative to component b is defined as: A large value of relative volatility, α ab implies that components a and b can be easily separated in a distillation column. Values of α ab close to 1 imply that separation will be very difficult, because the compositions of the liquid and the vapour
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Fundamentals & Principles of Distillation Relative Volatility (α) x-y diagram y a = VLE concentration of component a in the vapour phase y b = VLE concentration of component b in the vapour phase x a = VLE concentration of component a in the liquid phase x b = VLE concentration of component b in the liquid phase p a = vapour pressure of component a p b = vapour pressure of component b
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Exercise 4 – Relative Volatility Using data from table below, calculate the relative volatility for the benzene-toluene system at 85 o C and 105 o C.
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Distillation Process Goal & Basic Requirement Goal : separate less volatile components’ (heavy key) from “more volatile components (light key) by exploiting relative volatility, α ≠ 1. Basic Requirement : Composition of vapour must be different from liquid phase at equilibrium For α >> 1, this can be done very effectively unless an azeotrope exists (where α = 1).
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Batch & Continuous Batch Distillation Continuous Distillation Distillation Process
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Two Principal Methods Single-stage Partial Vaporization without Reflux (Flash Distillation) Vapour is produced by boiling the liquid mixture in a single stage and the vapour is condensed without any liquid returns to the stage Continuous Distillation with Reflux Some condensate returns to the stage in countercurrent flows to the vapours Distillation Process
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Flash Distillation of Binary Mixtures Flash distillation consists a vaporizing a definite fraction of the liquid in such a way that the evolved vapour is in equilibrium with the residual liquid, separating the 1 mole of a two- component mixture x F = mole fraction of the more volatile component, A Distillation Process
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x-y Diagram for Flash Distillation Distillation Process
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x-y Diagram for Flash Distillation q-line Distillation Process
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Continuous Distillation with Reflux Continuous distillation with Reflux is an ongoing separation in which a mixture is continuously (without interruption) fed into the process and separated fractions are Distillation Process
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Distillation Column Three (3) s ections: 1. rectifying (or enriching) section, 2. stripping (or exhausting) section and 3. feed section Rectifying section - more volatile component is removed through contacting the rising vapour with the down-flowing liquid.
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