As a carrier of oil and gas transmission, buried oil pipelines
are a link connecting upstream and downstream (analyzed by backward status), and are important facilities for surface engineering. Because the pipeline is buried in the ground for a long time, it will be affected by factors such as external soil characteristics and terrain settlement. Over time, the pipeline will undergo corrosion, perforation, and leakage, which will bring huge economic losses. If the leakage of harmful substances is caused, it will bring infection to the environment, and even cause sudden disasters, endangering people. For long-distance pipelines and gathering pipeline networks that transport oil and natural gas, the adoption of external anti-corrosion technology and construction quality of pipelines are directly related to the operation and service life of pipelines. Therefore, the anti-corrosion protection of buried oil and natural gas pipelines is increased.
Due to the complex terrain and different soil properties in the area where the pipeline crosses, different external anti-corrosion measures are required for buried steel pipelines. The main characteristics of the development of pipeline external anticorrosion technology are embodied in the high performance, compounding, long use time and good economy of anticorrosive materials.
(1) Petroleum asphalt anticorrosive layer:
The anticorrosion layer is composed of petroleum asphalt paint as the main material. There are two types of petroleum pitch available: one is petroleum pitch with a softening point of 95℃-110℃, which is used to transport buried pipelines whose liquid temperature is lower than 50℃; the other is petroleum with a softening point of 125-140℃ Asphalt is used to transport buried pipelines with liquid temperature in the range of 50-80℃. Petroleum asphalt anticorrosion layer has the advantages of wide raw material sources, low price, simple construction technology, etc., but also has shortcomings such as easy aging, poor soil stress resistance, poor heat resistance, and serious environmental pollution.
(2) Coal tar enamel paint anticorrosion layer:
Coal tar enamel is composed of coal tar, coal tar pitch and coal powder. There are three types of coal tar enamels available, and their softening points are greater than 100°C, 105°C, and 120°C. The casting temperature of these coal tar enamels is in the range of 230-260°C. Coal tar enamel has the advantages of good water resistance, high mechanical strength, chemical stability, anti-bacterial ability and strong resistance to plant roots, wide sources of raw materials, and low cost. Its disadvantage is soil resistance (texture types: loam, sand, Clay) has poor stress and thermal stability.
(3) Fusion bonded epoxy powder coating
The fusion-bonded epoxy powder anticorrosive layer is to spray epoxy resin powder with curing agent on the metal surface and bake it at 150-180℃ for 15 minutes to obtain a tough fusion-bonded epoxy powder anticorrosive layer.
Spiral insulated steel pipes can be used in pipelines, thermal equipment, machinery industry, petroleum geological exploration, containers, chemical industry and special purposes. Permanent Steel Manufacturing Co., Ltd's steel pipes are widely used in manufacturing industries such as construction, machinery, coal mines, chemicals, electric power, railway vehicles, automobile industry, highways, bridges, containers, sports facilities, agricultural machinery, petroleum machinery, and prospecting machinery.
The plastic-coated steel pipe has a hollow section and its length is much larger than the diameter or circumference of the steel. According to the cross-sectional shape, it is divided into round, square, rectangular and special-shaped steel pipes; according to the material, it is divided into carbon structural steel pipes, low-alloy structural steel pipes, alloy steel pipes and composite steel pipes; according to the purpose, it is divided into transportation pipelines, engineering structures, Steel pipes for thermal equipment, petrochemical industry, machinery manufacturing, geological drilling, high-pressure equipment, etc.; according to the production process, it is divided into seamless steel pipes and welded steel pipes, of which seamless steel pipes are divided into hot rolled and cold rolled (drawn) Two types, welded steel pipes are divided into two types: straight seam welded steel pipe and spiral seam.