Chapter 8, Problem 8.14NP

Interpretation Introduction

Interpretation:The maximum pressure at which the freeze drying can be carried out needs to be determined.

Concept introduction:

Freeze drying is a low temperature dehydration process that freezes the product by lowering the pressure then removes the ice through sublimation.

Sublimation is the process by which solid changes into gas phase without passing through the intermediate liquid state.

The Clausius-Clapeyron Equation is represented as follows:

  $\ln \frac{P_2}{P_1}=\frac{-\Delta H_{sub}}{R}\left(\frac{1}{T_2}-\frac{1}{T_1}\right)$

Here, P is pressure, R is Universal gas constant, T is temperature and $\Delta H_{sub}$ is change in enthalpy of sublimation.