Investigation of hydrate formation in natural gas flow through underground transmission pipeline

A natural gas underground transmission pipeline has been simulated by solving governing equations for one-dimensional non-isothermal compressible viscous flow in steady state condition. Temperature and pressure profiles have been calculated and temperature propagation distance has been calculated for various conditions. The natural gas is considered as a real gas and effect of composition has been studied. The possibility of gas hydrate formation as an important parameter in the natural gas pipeline has been investigated. Numerical calculations have been compared with previous studies. Results show that there is less than 3% difference between current and previous studies. Results also show that natural gas composition has no effect on temperature and pressure profiles but has a big effect on natural gas hydrate temperature and temperature propagation distance. For natural gas with low molar mass, the hydrate temperature is very low and consequently, the temperature profile along the pipeline is higher than the hydrate temperature. For natural gas with a higher molar mass and consequently low hydrate formation temperature, the natural gas temperature along pipeline may fall below the hydrate temperature.