Method of forming ice-phobic coating

#The invention rests in the field of oil and gas exploration and production, petroleum refining and petrochemistry, and pertains generally to the control of or influence over hydrate formation within conduits and the like, to improve or control flow characteristics, in particular hydrate formation in transporting and processing of water-containing hydrocarbon gases.

#Gas clathrate, also called gas hydrate or gas ice, is a solid form of water that contains a large amount of gas within its crystal structure. Such gas clathrates are found in formation fluids or natural gas, where hydrocarboneaous gas forms hydrates in conjunction with water. These hydrates usually exist in agglomerated solid forms that are essentially insoluble in the fluid itself.

#Thermodynamic conditions favouring hydrocarboneaous gas hydrate formation are often found in pipelines, transfer lines or other conduits, valves and/or safety devices, vessels, heat exchangers etc. This is highly undesirable because the gas crystals might agglomerate and cause plugging or blockage of the flow-line, valves and instrumentation. This results in shutdown, loss of production, risk of explosion and injury or unintended release of hydrocarbons into the environment either on-land or off-shore. Accordingly, natural gas hydrates are of substantial interest as well as a concern to many industries, particularly the petroleum and natural gas industries.

#In one aspect, the invention thus pertains to the use of an ice-phobic coating layer to reduce or even prevent gas hydrate adhesion to the interior surface of a conduit transporting or processing a fluid stream, in oil and gas exploration and production, petroleum refining and/or petrochemistry, wherein said ice-phobic coating layer is provided to the conduit interior surface, and wherein said coating layer: a) exhibits sessile water drop contact angle of at least 75° at ambient air conditions, as measured according to ASTM D7334-08; b) exhibits micro hardness of at least 200 HV (Vickers units) if exposed to fluid velocities lower than 50 m/s, as measured according to ASTM E384-08; c) exhibits corrosion rate of less than 0.1 μm/year; and d) is chemically inert.

#Additionally or alternatively, the invention also pertains to a method for reducing adhesion of solidified condensables, said condensables preferably comprising or being gas hydrates, to the interior surface of a conduit and/or associated equipment transporting or processing a fluid stream in oil and gas exploration and production, petroleum refining and/or petrochemistry by providing the conduit interior surface with a coating layer, preferably having a micro roughness of Ra less than 0.5 μm, exhibiting a static contact angle of the sessile water drop on the coating layer in air higher than 75° at ambient air conditions, as measured according to ASTM D7334-08.

#Also, the invention pertains to a method for transporting or processing a water-containing hydrocarbon fluid in a conduit or transport line, heat exchanger, separator or fractionator in oil and gas exploration and production, petroleum refining and/or petrochemistry at a temperature at or lower than the freezing or solidification temperature of said fluid, wherein the interior surface of said conduit, heat exchanger, separator or fractionator is provided with a coating layer (to reduce or even prevent adhesion of solidified condensables, said condensables preferably comprising or being gas hydrates, to the interior surface of said conduit, heat exchanger, separator or fractionator), preferably having a micro roughness of Ra less than 0.5 μm, exhibiting a static contact angle of the sessile water drop on the coating layer in air higher than 75° at ambient air conditions, as measured according to ASTM D7334-08.