The Saturated Water Content of Liquid Propane in Equilibrium with the sII Hydrate

Abstract

In order to prevent solids from forming during the transportation and handling of liquid propane, C3H8(l), the fluid is dehydrated to a level below the water dew point concentration for the coldest operating temperature. Thus, accurate calculation of the saturation water content for C3H8 is important to determine the designed allowable concentration in liquid C3H8. In this work, we measured the water content of liquid C3H8 in the presence of the structure II hydrate from p = 1.081 to 40.064 MPa and T = 241.95 to 276.11 K using a tunable diode absorption spectroscopy technique. The water content results were modelled using the reference quality reduced Helmholtz equations and the Sloan et al. model for the non-hydrate and hydrate phases, respectively. Calculations show a good agreement (an average difference of less than 12 ppm) when compared to our measurements. Furthermore, the model was also used for calculating the dissociation temperatures for three phase loci, where a relative difference greater than 5 K was observed compared to the literature, hence our previously model reported by Adeniyi et al. is recommended for three phase loci calculations.

Keywords

• propane
• structure type II hydrate
• water content
• flow assurance