Impact of Heavy Hydrocarbon Concentration on Natural Gas Flow through Transportation Pipelines

Abstract

In this work, binary, ternary, quaternion, and quinary natural gas mixtures were evaluated including methane, ethane, propane, butane, and pentane to highlight their impact on pipeline performance and thermophysical properties of natural gas. The results presented that all the heavy hydrocarbons have a negative impact on natural gas phase envelope. For binary mixtures, methane/propane recorded the widest two-phase envelopes while the quinary mixtures generally formed the widest two-phase envelopes over the other mixtures. Besides, the heavy hydrocarbons content of different mixtures increased the critical pressures and critical temperatures in comparison to pure methane. The highest temperature drop of 6.495 °C was recorded by the binary mixture and the lowest temperature drop of 6.341 °C was by quinary mixture. The highest pressure drop of 4.964 bars was caused by the quinary mixture, while the lowest pressure drop of 4.1 bars was by the binary mixture. In addition, the results showed that natural gas density controlled by methane content caused increasing the methane content resulting in reducing the density of natural gas mixture. The viscosity of natural gas is a sensitive parameter to the content of the heavy hydrocarbon concentrations and all heavy hydrocarbons increased the viscosity of natural gas in comparison to pure methane.