5. Processes based on supercritical fluid technology

The two-dimensional representation (p, T ) of the phase diagram of a pure body (figure 23 ) allows us to locate the different states of this pure body. The boundaries of these domains (solid lines) correspond to liquid-gas, solid-liquid and solid-gas transitions, and thus to discontinuities in specific volume and density. Point C, where the liquid-gas curve ends, is called the critical point. It corresponds to a critical temperature, pressure and density. Beyond C, an intermediate state between liquid and gas appears, known as the supercritical state.