Experimental study on flow characteristics of tetrahydrofuran hydrate slurry in pipelines

Tetrahydrofuran (THF) was selected as the substitute to study the flow behaviors and the mechanism of the hydrates blockage in pipelines. The slurrylike hydrates and slushlike hydrates are observed with the formation of hydrates in pipeline. There is a critical hydrate volume concentration of 50.6% for THF slurries and pipeline will be free of hydrate blockage while the hydrate volume concentration is lower than the critical volume concentration; otherwise, pipeline will be easy to be blocked. Fully turbulent flow occurs and friction factors tend to be constant when the velocity reaches 1.5 m/s. And then, constant values of friction factors that depend on the volume concentrations in the slurry were regressed to estimate the pressure drops of THF hydrate slurry at large mean velocity. Finally, a safe region, defined according to the critical hydrate volume concentration, was proposed for THF hydrate slurry, which may provide some insight for further studying the natural gas hydrate slurries and judge whether the pipeline can be run safely or not.