V

nn hv hv

At first glance , these assumptions may seem restrictive, but the assumption of constant molar flows actually holds well for many industrial mixtures.

In a binary column where the last assumption about equal AHbpp is not fulfilled, a good estimate of the change in molar flows from the bottom (stage 1) to the top (stage N), due to this effect for a case with saturated liquid feed (q = 1) and close to pure products, is given by: Vn/V + AHHap/AHLap, where the molar heat of vaporization is taken at the boiling point temperatures for the heavy (H) and light (L) components respectively.

Recall that the temperature dependency of the relative volatility is related to different heat of vaporization also, thus the assumptions of constant molar flows and constant relative volatility are closely related.

Calculation of Temperature when Using Relative Volatilities

It may seem that we have lost the pressure and temperature in the equilibrium equation when we introduced the relative volatility. However, this is not the case since the vapour pressure for every pure component is a direct function of temperature, thus it is also the relative volatility. From the relationship P = £ pi = £ xi po(T) we derive:

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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