Composite polyethylene (PE) powder thermally sprayed anticorrosion coating for petroleum and natural gas pipe

Abstract

The invention provides a PE powder thermally sprayed anticorrosion coating for a petroleum and natural gas pipe, which is a blended interface anticorrosion coating formed on the inner or outer wall of the petroleum and natural gas pipe by thermally spraying low-temperature setting epoxy powder (PBE), holt melt polymer gel (AD) and modified polyethylene (PE) / propenepolymer (PP) powder on the inner or outer wall of the petroleum and natural gas pipe in turn. The anticorrosion coating has an ultrahigh stripping strength for the petroleum and natural gas pipe, overcomes the AD / PE intra-layer separation of the conventional 3PE anticorrosion technology, and improves the anticorrosion performance of the pipe; and the anticorrosion layer eliminates a cathode shielding area, improves cathode protection resistance, reduces drawbacks of 'edge turning' at a weld joint part and effectively reduces coating cost due to a one-time spraying process.

Description

technical field [0001] The invention relates to the field of anti-corrosion of oil and gas pipelines, in particular to a method for making oil and gas pipelines have high-performance anti-corrosion coatings by spraying different coatings on oil and gas pipelines and the formed anti-corrosion coatings. Background technique [0002] The 3PE anti-corrosion process was introduced to China in the late 1990s. The introduction of this technology has changed the domestic practice of using asphalt, coal tar pitch, epoxy coal tar pitch and other materials to coat various buried pipelines for anti-corrosion. Technology has greatly extended the service life of buried pipelines, and the protection time of the anti-corrosion layer has been extended from an average of about ten years to thirty years or even longer. With the continuous promotion of 3PE technology, most of the current domestic pipelines (including crude oil, natural gas, gas, and some water pipelines) have adopted 3PE anti-c...

AI Technical Summary

Problems solved by technology

[0004] However, with the rapid development of long-distance oil and gas pipelines in the country, the traditional 3PE pipeline anti-corrosion technology can no longer meet the requirements of high steel grade, high pressure, large transmission volume and long life

Although 3PE anti-corrosion technology has many advantages, there are still some problems in 3PE anti-corrosion technology in the production process that need to be solved urgently

First of all, since the adhesive and jacket material layer of 3PE anti-corrosion technology are extruded by an extruder to form a film and directly cover the surface of the steel pipe, the uneven weld seam at the joint of the steel pipe cannot be fully contacted, resulting in lateral extrusion of the polyethylene layer The thinning of the coating at the front of the weld slope and the "hollowing of the back slope" defect of the weld lead to the appearance of a cathode shielding area in the future use process, which affects the anti-corrosion performance of 3PE, and the direction-finding winding lap may form corrosion channels

Secondly, during the coating process, the air is easily wrapped into the 3PE, making bubbles appear on the surface of the 3PE anti-corrosion layer

Thirdly, in the production process of rubber and jacket materials, it needs to be reheated, which not only consumes a lot of electric energy, but also the mixing effect of the extruder will cause certain damage to the product performance, which is not conducive to the evaluation of product performance

Finally, when the anticorrosion plant shuts down and starts up again, it is necessary to clean up the residual material in the extruder, which causes a lot of waste and increases the operating cost of the anticorrosion plant

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