An evaluation of risk of hydrate formation at the top of a pipeline

Water condensation and/or hydrate formation at the top of pipelines are serious design/operation consideration in pipelines with stratified flow. Water condensation could result in top of the line corrosion, in particular in sour gas systems. Hydrate formation is believed to be another serious risk if the inhibitor in the aqueous cannot protect hydrate formation at the top of the pipeline.

In this communication we report the results of some preliminary tests conducted in a new experimental set-up constructed for investigating gas hydrate risks in various operational scenarios, e.g., top of pipelines, dead legs/jumpers, start-ups, shut-downs, etc. The reported series of tests conducted in the new experimental set-up address hydrate formation risks at the top of pipelines or dead legs due to temperature gradient, amd risk of hydrate formation in the gas phase in the presence KHI during pipeline cool down and start-up. The results give a better evaluation of the risks involved in various systems and provide guidelines for avoiding the associated problems.