Hydrate plug dissociation

It was shown that flowline hydrate plugs dissociate radially not horizontally; this has significant implications for the remediation of a hydrate blockage, a major flow assurance problem. Over a decade of measurements has enabled models to estimate the dissociation time for hydrate plugs in flowlines, using radial heat transfer with two moving boundaries. Three different plug dissociation scenarios were modeled: single-sided depressurization, two-sided depressurization, and dissociation by radial electrical heating. The models were able to replicate the experimental observations with no fitted parameters. Structure I hydrate was found to dissociate faster than structure II; this was attributed to the different latent heats between the structures. These results indicate that hydrate dissociation in these systems is limited by heat transfer. (c) 2006 American Institute of Chemical Engineers.