2. Principle of supercritical CO2 cleaning

2.1 Definition of the supercritical range

Like any pure body, CO ₂ can be found in three different states of matter: the liquid, solid or gaseous state, depending on the thermodynamic parameters of pressure P, temperature T and volume V and quantity of matter n (mole). These parameters, known as variables of state, are not independent and are linked by an equation of state. A simple expression of this equation of state is the well-known perfect gas equation.

In figure 2 is given the phase diagram P = f (T ) of CO ₂ . The lines represented on this diagram correspond, at a given pressure,...