Lined vessels for conveying chemicals

Abstract

The present invention relates to a vessel, in particular a pipe, especially an oil pipe, having a preformed film adhered onto the interior surface of the pipe, the interior surface of the preformed film reducing the deposition of at least one of asphaltenes, paraffin wax, and inorganic scale by at least 40% as compared to the interior surface of said oil pipe without said preformed film being present. In a preferred embodiment, the preformed film is adhered to the interior surface of the pipe with a primer layer with an optional barrier layer between the primer layer and the preformed film.

Description

FIELD OF THE INVENTION [0001] This invention relates to vessels or pipes that store or convey chemicals and more particularly to linings for the interior surface of such vessels. In particular, the vessel may be a storage tank or an oil conveying pipe. BACKGROUND OF THE INVENTION [0002] Pipes used in the production and transportation of chemicals are subject to corrosion and plugging. An example of such a pipe is oil pipe which is generally large and for reasons of economy is manufactured from carbon steel rather than more expensive corrosion resistant alloys. Corrosion is induced by the hot underground environment in which down-hole pipes convey oil from deeply buried deposits to the earth's surface. Materials such as water, sulfur, sulfur dioxide, carbon dioxide, present in the oil typically make it acidic causing corrosion of the interior surface of the pipe. Even at cooler temperatures, transportation pipelines that extend for long distances close to the earth's surface experien...

AI Technical Summary

Benefits of technology

[0005] The present invention satisfies the need by providing a pipe for conveying chemicals, especially an oil conveying pipe (oil pipe) having a nonstick interior surface formed by a preformed fluoropolymer film adhered to its interior surface. The preformed film is capable of reducing-to-eliminating the deposition (buildup) of one or more of the asphaltene, paraffin wax, and inorganic scale on the interior surface of the oil pipe. Preferably, this reduction is at least 40%, preferably at least 50%, for at least one of these materials as compared to the unlined oil pipe, and more preferably at least 40% for all of them. These percent reductions can be determined by periodic measurements of the amount of build-up within the pipe or simply by observing the more than double the production time before the oil well must be shut down for cleaning. These deposition reductions are accompanied by the added benefit of corrosion protection as compared to unlined oil pipe. The reduced deposition performance of the lined pipes of the present invention is in contrast to the result obtained for epoxy resin-lined oil pipe, wherein the deposition is greater than for the unlined pipe.

Problems solved by technology

Pipes used in the production and transportation of chemicals are subject to corrosion and plugging.

Corrosion is induced by the hot underground environment in which down-hole pipes convey oil from deeply buried deposits to the earth's surface.

Materials such as water, sulfur, sulfur dioxide, carbon dioxide, present in the oil typically make it acidic causing corrosion of the interior surface of the pipe.

Even at cooler temperatures, transportation pipelines that extend for long distances close to the earth's surface experience the effects of corrosion because of the long contact times involved.

Corroded pipes are difficult and expensive to replace.

The resultant insoluble materials, such as asphaltenes and paraffin waxes, tend to plate out on the interior surface of the pipe, restricting the oil flow and eventually plugging the pipe.

An additional problem arises from soluble inorganic material, commonly referred to as scale and generally comprising calcite and / or barite, present in the oil or in the salt water associated with the conveying of oil from underground deposits.

Such cleaning reduces productivity and involves large maintenance costs.

Similar problems occur for oil storage vessels and pipes and storage vessels used in the manufacture and transportation of corrosive chemicals in the Chemical Processing Industry (CPI).