Characteristics of Petrochemical Pipelines and Metal Surface Treatment of Pipelines

≪ One> The characteristics of gear pump pipelines

The installation of gear pump pipelines is a part of the construction process in metallurgical industry, power industry, petroleum and nuclear industry, etc.

. In the production process, process pipelines are generally used to maintain the operation and transportation of various materials between equipment. In production, pipelines are generally used to transport media, and these media are generally high temperature, high pressure, flammable, explosive, toxic, and substances. If there is a slight carelessness during transportation, it may cause serious accidents such as leakage or explosion, causing irreparable losses to humans and society. Therefore, for pipelines that cover almost every corner of the factory, it is necessary to strictly ensure the correct installation and construction quality of the pipelines

The installation process of pipelines is complex and involves a wide range of procedures. The requirements for various aspects of the process pipeline, such as material, pressure, temperature, etc., vary according to different production needs. Therefore, the required pipes, fittings, valves, etc. in the production process also vary greatly. Due to the widespread application of oil pump pipelines in industrial production, their installation quality is particularly important. Therefore, the analysis and research of common problems in pipeline installation in recent years have attracted widespread attention from society. Further discussion and reference are made to the experience and lessons learned from various industries in pipeline installation, in order to strengthen the quality control of gear pump pipeline installation and ensure the normal operation of each part during operation after installation

1) There are various types of pipes, and due to the variety of production processes and techniques, the operating temperature, operating pressure, and the corrosiveness of transportation media in production will also vary.

. Therefore, different production processes may use different pipes. There are various types of pipes, including stainless steel, carbon steel, alloy steel, as well as other non-ferrous and non-metallic pipes. This also makes the types of valves, fittings, and flanges corresponding to it particularly complex during pipeline installation. In order to ensure production efficiency, various materials of pipes are used according to different media and process conditions during the product production process, so as to ensure the normal operation of production

2) Characteristics of the conveying medium: In the production process of the product, there are various types of raw materials used, and they are flammable and explosive.

. Common examples include acetylene gas, coal gas, hydrogen sulfide, hydrogen gas, and methanol. These media may self ignite under temperature conditions or explode in high-temperature environments. At the same time, many products are also toxic. When toxic substances are inhaled or come into contact with people, it can cause poisoning or serious damage to the body, and in severe cases, it may. The corrosiveness of products is also a common characteristic, such as sulfuric acid, nitric acid, and alkali. According to the requirements of the production process, some media in many product production processes need to undergo high temperature and high pressure treatment in order to undergo the chemical reactions required in the production process and obtain the required products

3) The construction quality acceptance standard is relatively high. In order to ensure the smooth operation of the production process based on the different characteristics of the transported raw materials mentioned above, strict requirements are placed on the construction quality of the gear pump pipeline installation during the pipeline installation process, especially the inspection of the pipe mouth weld seam. Welding defects are never allowed to occur to avoid seriously affecting the strength and airtightness of the pipeline.

. Strictly follow the specified inspection standards and acceptance specifications to inspect various types of pipe mouth welds, and also develop construction acceptance specifications to ensure good acceptance of the pipelines. During the installation process of gear pump pipelines, whether for overhead pipelines or buried pipelines, proper handling should be carried out, and the pipelines should be inspected and accepted strictly in accordance with the standard "Code for Construction and Acceptance of Industrial Pipeline Engineering"

< II The metal surface treatment technology in front of the pipeline

1. Rigid polyurethane foam insulation combined insulation

This technology has been applied in the oil field for more than 30 years. The "one-step" production process is mature, and the project cost is low. This process can isolate the infiltration of air and water, and play a good role. At the same time, its foam pores are all small circular holes that are individually closed and not connected to each other, with a closure rate of over, so its water absorption rate is about 0.2kg/m3. With low thermal conductivity and water absorption rate, coupled with a high-performance polyethylene or fiberglass protective shell outside the insulation layer, it overcomes the traditional situation of laying wet cotton jackets in the trench, and reduces the overall heat loss of heating pipelines. Practice has proven that as long as the design and construction are carried out according to regulations, it is generally not a problem to use it for 50 years

Measures: (1) Correctly select the combination of polyether and isocyanate, choose different foaming parameters according to the size of the steel pipe, improve the foaming quality of the steel pipe, and select matching isocyanates.

. (2) Before construction and start-up, check that the equipment is in good condition, and then adjust the line. The center line of the equipment is consistent. Prepare the relevant raw materials according to the proportion. When starting, feed the materials evenly (foam is inclined to achieve a better foam state). Motor matching, stable pipeline feeding. (3) Using high-pressure fluorine free foaming machine: accurate temperature control: accurate measurement: modular design

2. Two layer PE protection technology

Two layer PE protection technology has good performance, low water absorption rate, and is widely used in water, gas, and oil pipelines due to its mechanical properties.

. The two-layer PE technology consists of a bottom layer of epoxy powder, a middle adhesive, and an outer layer of composite polyethylene. For the sake of effectiveness, sandblasting or rust removal is used on the surface of the steel; Produce when humidity and temperature are appropriate. Select layers with different levels of structure based on different soil corrosion environments. The steel pipe is uniformly heated to a suitable temperature using a medium frequency power supply; Electrostatic spraying solvent-free epoxy powder, adhesive winding, polyethylene winding, water cooling

3. Inner coating

The coating has strong corrosion resistance to the medium, can prevent the corrosion of the upper medium on the gear pump pipeline, and has a long service life;

; The construction process is relatively simple, easy to master, and the construction quality is easy; Compared material supply and good economy; Maintenance and repair are relatively easy, and internal technology is widely applied to water supply pipelines. Measures: For internal effects, sandblasting or rust removal should be used on the surface of the steel; Production when humidity and temperature are appropriate: The internal protective coating is configured according to requirements