A hydrocarbon mixture converts from liquid phase to vapour phase over a range of temperature for a given pressure. Bubble point or bubble point temperature is the temperature value for a given pressure at which first bubble of vapour is formed out of liquid hydrocarbon mixture. The temperature value for a given pressure at which last drop of liquid hydrocarbon mixture converts to vapour is known as hydrocarbon dew point. Bubble point for a hydrocarbon mixture is also known as initial boiling point where as hydrocarbon dew point for a hydrocarbon mixture is also known as final boiling point.
A pure hydrocarbon converts from liquid phase to vapour phase at a constant temperature for a given pressure. This means that for a pure hydrocarbon, bubble point and hydrocarbon dew point temperature values for a given pressure, coincide and there exists just a single boiling point for pure hydrocarbons. For pure hydrocarbons, no boiling point or bubble point values exist for pressure values beyond critical pressure. For a hydrocarbon mixture, normally only one bubble point temperature value exist for low pressures. For some hydrocarbon mixtures, two bubble point temperature values exist for high pressures beyond critical pressure. Also for some hydrocarbon mixtures with high concentration of non-condensables, a broken bubble point curve with more than one critical points exist. In such cases, for some intermediate pressure values, no bubble point temperature values exist. For hydrocarbon mixtures, no bubble point or hydrocarbon dew point values exist for pressure values beyond cricondenbar pressure.
Bubble point values find extensive usage in designing of distillation columns. Also bubble point values are required in designing of many other hydrocarbon equipments like liquid hydrocarbon pipelines, hydrocarbon pumps, hydrocarbon storages etc. and in oil reservoir simulation studies.
Bubble point calculator / bubble point software like EQ-COMP can calculate bubble point temperature values for a given pressure value and bubble point pressure values for a given temperature value for nonpolar or mildly polar hydrocarbons and inorganic gases and their mixture. Results for bubble point temperature values for a given pressure value can be requested from http://www.eq-comp.com/bubble-point-temperature-calculator-software/ webpage and results for bubble point pressure values for a given temperature value can be requested from http://www.eq-comp.com/bubble-point-pressure-calculator-software/ webpage.