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SwRI develops innovative coating for offshore drilling pipes

Research and development organisation Southwest Research Institute (SwRI) has developed a new superhydrophobic coating to prevent offshore drilling pipes from becoming clogged.

The coating, which is called LotusFlo™, was recently recognised by R&D Magazine as one of the 100 most significant innovations of 2019, along with the unique process developed to apply the coating to pipes.

“Offshore oil drilling faces a number of challenges in extracting petroleum from beneath the ocean floor,” said Dr. Michael Miller, SwRI institute scientist and one of LotusFlo’s principal developers. “Pipes are frequently clogged by substances like asphaltenes, which are sticky and tar-like molecular substances found in crude oil; paraffins, soft waxy materials that are derived from petroleum; and inorganic scales, which are mineral deposits that form when water mixed with different types of salty liquids.”

These substances can slow or even stop the flow of oil through pipes, with current solutions involving the use of expensive chemicals that can pollute the surrounding ocean.

The LotusFlo coating can repel the liquids and materials that often clog drilling pipes is applied to pipes under vacuum conditions. The coating contains silicon, oxygen, carbon and fluorine, and in spite of harsh conditions in the drilling environment, can last for years and does not harm the surrounding environment.

The unique application process involves linking several 40ft sections of pipe together in very low atmospheric pressures. The interiors act as a vacuum chamber, with an end unit on either side of the pipe providing the vacuum source. An electrode is passed through and suspended in the middle of the pipe.

Volatile molecules are then introduced into the evacuated pipe to ignite highly ionised gas molecules, or plasma, inside the length of the pipe. The plasma, once ignited, emits light and fragments to allow control over the chemical precursor molecules to form other ions in the plasma, which are then accelerated onto the internal surface of the pipe.

When the ions collide on the interior surface, they undergo a polymerisation reaction that results in a partially inorganic, glass-like coating that keeps the materials from adhering to pipe surfaces.