Oil and gas pipeline anti-corrosion coating technology

corrosion is a fundamental factor affecting the life and reliability of oil and gas pipelines on the seabed and buried areas, so when designing and constructing pipelines, corrosion-resistant coatings are usually applied to the pipes, along with an effective cathodic protection system to effectively resist pipeline corrosionOver the past 50 years, oil and gas pipelines have been coated with many different types of coatings, such as coal tar porcelain paint, petroleum asphalt, polyolefin strap, two-layer extruded polyethylene coating, single- or double-layer blended epoxy powder coating, reinforced three- or multi-layer polyene (polyethylene or polypropylene) coating, etcWith the development of the petroleum industry, oil and gas pipelines need to be applied in some special environments, and pipeline coating systems need to be technologically innovativeBrederoShaw Canada has the largest team of technology and service experts in the industry, with 27 pipe coating lines on six continentsSeveral unique and advanced protection technologies designed by the company for land and submarine pipelines, including high-efficiency composite coating systems (HPCC), high-strength steel powder coating cryogenic coating technology and Thermotite steady flow assurance technology, have been proven in field applications1The High Efficiency Composite Coating System (HPCC)High Efficiency Composite Coating System (HPCC) is a multi-component coating system coated with a full powder: the inner layer is FBE (melted adhesive epoxy resin), the outer layer is a medium density polyethylene coating, and the middle layer is a chemically modified polyethylene adhesive that acts as a bonding effectAll materials in three parts of this composite coating are coated by an electrostatic powder coating systemThe intermediate bond layer is a mixture of adhesive and a certain concentration of FBE, so that there is no burr between the adhesive and the underlying FBE, or between the adhesive and the outer polyethylene coating, and has a clear interfaceAdhesives and polyethylene are actually similar substances that can be easily mixed together, so coatings can be closely linked to each other and do not layer like a single coating systemEven with significant temperature variations, the internal stress growth of the HPCC is minimalHPCC has excellent adhesion to the pipe surface, excellent inherent shear resistance characteristics, low gentle toughness, impact resistance, cathodic peeling and very low permeability2High-strength steel powder coating low temperature coating technology
At present, high yield strength steel is more and more used in the construction of oil and gas pipelinesIn cold climates, coatings coated with high-strength steel must be able to withstand low temperatures and maintain the flexibility required by the pipes As a general practice, the steel pipe should be preheated to 240 degrees C before applying an FBE coating However, such a high preheating temperature will change the metallurgical properties of high-strength steels, making metals more brittle, making steelless against cold climates In order to maintain the mechanical properties of high-strength steel, the coating temperature of the steel pipe must be less than 200 degrees C when applying the FBE coating BrederoShaw developed a special coating HPCC process that allows the coating temperature to drop below 180 degrees C, with satisfactory results in pipeline projects in Canada and the United States The coating is not damaged during the unloading and fitting of casings at the construction site, and no damage to the anti-corrosion layer is caused at low temperature bending at -45 degrees C 3 Thermotite Steady Flow Guarantee Technology Thermotite Insulation and Steady Flow Guarantee Technology is used to meet the requirements of corrosion, insulation and smoothness assurance Thermotite technology is composed of multi-layer polyethylene, the bottom layer is connected to the steel substrate by melting epoxy powder The structure of the five-layer system is coated by side or press, and the inside three layers should be quality tested before coating the outside two thermal insulation layers (polypropylene foam layer and outer jacket layer) On thermal insulation lines, polypropylene foam layers and outer jacket layers should be coated simultaneously by pressing and squeezing to ensure that no air is included in the foam compared with the traditional polypropylene foam structure, the application on the Thermotite system is a special polypropylene foam, its foam cell structure is more reasonable This foam has many excellent properties, such as high melting strength, high peristalsis resistance and high hardness, and can be applied under water up to 1500 m deep If more than seven layers of insulation system solutions can be applied under deeper water, glass particles can be added to matrix solid polyethylene to reinforce and form a composite foam to improve the water depth and low temperature performance of multi-layer polypropylene systems