Heat transfer and multiphase flow with hydrate formation in subsea pipelines

This study presents a new semi-analytical model to predict hydrate formation in subsea pipelines. The numerical formulation is based on a non-dimensional analysis, allowing the model to be extended to various pipeline lengths and environmental conditions. The effects of change in heat transfer ratio (HTR), and pipe diameter on hydrate formation are reported in this paper. The results indicate that higher HTR between the internal and external fluids reduces the formation of hydrates which may lead to a blockage in the pipeline. The numerical results are validated against experimental results for R134a hydrates. The pipes with smaller diameters are found to reduce the possibility of hydrate formation at a constant pipeline pressure. The results show that at temperatures below -10°C, changing thermophysical properties have limited impact on the rate of hydrate formation in the pipe.