K-value of Several Hydrocarbons versus Temperature and Pressure

This Demonstration shows the contour plot of versus temperature expressed in °R and pressure expressed in psia, where and are the mole fractions of component in the liquid and vapor phases, respectively. For many systems, -values are approximately independent of composition and we have .

For light hydrocarbons, the approximate -values can be determined from DePriester charts, which have been fit to the following equation: , where the constants , , , , , and are tabulated [1]. Drag or click the locator to display the values of the temperature and pressure as well as the -value for various light hydrocarbons.