Cricondentherm, Cricondenbar and Critical Point

• Cricondentherm (Tct)—The Cricondentherm is defined as the maximum temperature above which liquid cannot be formed regardless of pressure (point E at Pressure-Temperature Diagram). The corresponding pressure is termed the Cricondentherm pressure pct.
• Cricondenbar (pcb)—The Cricondenbar is the maximum pressure above which no gas can be formed regardless of temperature (point D at Pressure-Temperature Diagram). The corresponding temperature is called the Cricondenbar temperature Tcb.
• Critical point—The critical point for a multicomponent mixture is referred to as the state of pressure and temperature at which all intensive properties of the gas and liquid phases are equal (point C at Pressure-Temperature Diagram). At the critical point, the corresponding pressure and temperature are called the critical pressure pc and critical temperature Tc of the mixture.

Ahmed (2001)

Pressure-Temperature Diagram

The conditions under which oil or gas phases exist are a matter of considerable practical importance. The experimental or the mathematical determinations of these conditions are conveniently expressed in different types of diagrams commonly called phase diagrams. One such diagram is called the pressure-temperature diagram.

Figure shows a typical pressure-temperature diagram of a multicomponent system with a specific overall composition.

These multicomponent pressure-temperature diagrams are essentially used to:

• Classify reservoirs
• Classify the naturally occurring hydrocarbon systems
• Describe the phase behavior of the reservoir fluid

Ahmed (2001)