Development of a Method for Direct Determination of Dew Point Loci of Methane-Heavier Hydrocarbon Mixtures at Low Temperatures and Elevated Pressures

Abstract

The K-value data in the low-temperature range for methane with other alkanes heavier than propane are scarce in the literature or are often unreliable. This has been caused by the difficulty in the determination of the dew point concentration. The concentration of the heavier component in the vapor phase becomes very small as the system temperature goes down. It is inherent in ordinary chromatography methods that more errors occur in determining concentrations lower than 100 ppm. Errors will be caused by adsorption on the tube wall, characteristics of the packing material for the chromatographic column, or the sampling technique. The calibration of the chromatographic detector also becomes more difficult since it is difficult to prepare a very dilute mixture without appreciable errors.