Gas Hydrate Deposition on a Cold Surface in Water-Saturated Gas Systems

Abstract

One of the major issues in flow assurance includes pipeline plugging due to hydrate formation and deposition. A key uncertainty in gas pipelines is hydrate deposition on the pipe wall. This work demonstrates hydrate formation and deposition on a cold surface in water-saturated gas systems. Methane hydrate deposition can be achieved in a laboratory-scale apparatus by formation of hydrates from the gas phase on the outer surface of a cold surface. The deposit evolves from the initial formation to growth to hardening stages, observed to be initially a porous deposit that later anneals to a relatively nonporous deposit. The hydrate deposit thickness gradually reaches a limit as the hydrate surface approaches the hydrate equilibrium temperature. Performing the measurements at higher initial subcooling in the system results in a thicker hydrate deposit. The average calculated hydrate deposit porosity decreases during the experiment and reaches ∼5% during the annealing stage.