A numerical model is developed to examine the flow conditions of multiphase heat transfer and entropy production during hydrate formation in subsea pipelines. The temperature and pressure gradients of the oil and gas flow in subsea pipelines lead to entropy generation. This paper examines the impacts and effects of thermodynamic irreversibilities on the nucleation and growth processes of hydrate crystals in the pipeline flows. The effects of heat transfer ratio, internal diameter of the pipe, molar gas density, and environment temperature on entropy production in subsea pipelines are predicted and discussed in this paper. The numerical model accounts for the temperature distribution along the axial length of the pipe, reaction kinetics, and mass transfer between the solid and fluid layer. The kinetic energy of the hydrate particles during the coagulation process is analyzed in the numerical model. The results indicate that entropy production is highest at the beginning of the nucleation process. Pipelines with smaller internal radii have a lower rate of hydrate formation in subsea pipelines. The results from the numerical model are verified by comparison with experimental results for structure type Ⅱ natural gas hydrates.
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