A new hydrate deposition prediction model considering hydrate shedding and decomposition in horizontal gas-dominated pipelines

Abstract

Hydrate formation and blockage in gas-dominated pipelines has always been an important issue in research of pipeline flow assurance. In this work, a novel hydrate deposition prediction model considering hydrate shedding and decomposition for gas-dominated pipeline is proposed and solved by the finite difference method and iterative technique. Finally, the model has been applied in the existing gas-dominated pipeline experiments. The results show that: (a) the predicted results are in good agreement with the experimental data. (b) when the maximum degree of pipeline blockage reaches the blockage limit, the hydrate layer will shear off, and the layer that has been sheared tends to fall off twice. (c) when the pressure is the same, the higher the negative subcooling (N-subcooling), the faster the hydrate decomposition rate, and when the N-subcooling is similar to the subcooling, the decomposition with the same hydrate volume is faster than the formation. (d) increasing the hydrate shedding amount or increasing the hydrate decomposition rate can be used to deal with hydrate deposition and blockage accidents in natural gas pipelines.