Superhydrophobic coating developed for offshore drilling pipes
The Southwest Research Institute’s (SwRI) LotusFlo is a superhydrophobic coating to keep offshore drilling pipes from being clogged by various substances.
“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.”
All of these substances can slow or even halt the flow of oil through the pipes. Current solutions involve pouring costly chemicals, which also pollute the surrounding ocean, down pipes to unclog them. The LotusFlo, however, is a superhydrophobic coating technology that can repel the liquids and materials that often clog drilling pipes. The coating, which is applied to the pipes under vacuum conditions, contains silicon, oxygen, carbon and fluorine. Despite the harsh conditions of the drilling environment, the coating can last for years and is not harmful to the surrounding environment.
The LotusFlo coating process involves linking several 40-ft sections of pipe together in very low atmospheric pressures. The interiors essentially act as a vacuum chamber, with an end unit on either side of the pipe providing the vacuum source. An electrode is strung through the pipe from one end to the other and suspended in the middle of the pipe.
Volatile molecules are then introduced into the evacuated pipe to ignite highly ionized gas molecules, or plasma, inside the entire length of the pipe structure. The plasma, once ignited, emits light and fragments in a special way to allow control over the chemical precursor molecules to form other ions in the plasma, which are then accelerated very rapidly onto the internal surface of the pipe. When the ions collide on the interior surface, they undergo a polymerization reaction that results in a partially inorganic, glass-like coating that keeps the materials from adhering to pipe surfaces.