MIT researchers design new coating to prevent clogging of pipelines
Siobhan Treacy | April 18, 2017A team at MIT, led by Kripa Varanasi, has created a new method of preventing icy buildup and leakages in oil and gas pipelines. The method involves coating the inside of the pipeline with a layer of a material that promotes spreading of a water-barrier layer along the pipe’s inner surface. The barrier layer can effectively prevent the adhesion of ice particles or water droplets to the wall, which stops the buildup of clathrates that could slow or block the flow.
This new method is completely passive, unlike previous methods. Once in place, it requires no further addition of energy or material. The coated surface attracts liquid hydrocarbons that are already present in the flowing petroleum and creates a thin surface layer that naturally repels water. This prevents ice from attaching to the pipe walls.
Prevention measures in currently place, called flow assurance measures, are expensive and environmentally unfriendly, according to Varansi. But without these measures, hydrates build up and slow the flow rate, which in turn slows the revenues and creates blockages. This could lead to a failure like the explosion at the Deepwater Horizon oil rig explosion on April 21st, 2010.
Blockage problems could grow even more because methane hydrates, which are abundant in continental shelves, are seen as a huge new potential fuel source. But the deposits would be even more vulnerable to freezing and plug formation than the existing oil and gas wells. Preventing the buildups depends critically on stopping the first particles of clathrate from adhering to the pipe.
Varansi’s extraction approach is similar to another coating being used in a company he established to commercialize his earlier lab work, which creates coatings for containers that prevent contents from sticking to the container walls. This system involves two steps: creating a textured coating on the container walls and adding a lubricant that gets trapped by the texture and prevents contents from adhering.
The new pipeline system is similar to that but in this case “we are using the liquid that’s in the environment itself,” Varanasi explains, “rather than applying a lubricant to the surface. The key characteristic in clathrate formation is the presence of water, he says, so as long as the water can be kept away from the pipe wall, clathrate buildup can be stopped”. As long as the hydrocarbons present in petroleum cling to the wall due to the chemical affinity to the surface coating can effectively keep the water away.
The research was funded by the Italian energy company Eni S.p.A through the MIT Energy initiative. The paper named Designing Ultra-Low Hydrate Adhesion Surfaces by Interfacial Spreading of Water-Immiscible Barrier Films was published in the journal ACS Applied Materials and Interfaces. Read the paper here.