A construction process for a clean material production line using EP pipes

Abstract

The present invention discloses a construction process of a clean material production line using EP pipes, and relates to the technical field of EP pipes. The material of the discharge pipeline, which is 304 steel lined with fluorine, is changed into an EP pipe. The connection between the pipes is welded by automatic welding. The EP pipe is filled with PVDF emulsion and placed outdoors in the sun for 2 weeks. The 316L stainless steel pipe is electrolytically polished and then cut into standard specimens and placed in a salt spray tester for testing. The invention uses 316L EP pipes, which have good corrosion resistance. The surface is polished and has the characteristics of smoothness and flatness, which reduces the roughness of the inner wall of the pipe, reduces fluid resistance and dirt deposition, and improves the transmission efficiency of the fluid. The automatic welding technology is adopted, and the automatic welding quality is good, the efficiency is high, and the construction cost is saved. The internal pipe is clean and smooth without residue, and the product yield is improved.

Description

Technical Field

[0001] The invention relates to the technical field of EP pipes, and in particular to a construction process of a clean material production line using EP pipes. Background Art

[0002] With the need for high-quality development in the country, higher and higher requirements are placed on the purity and cleanliness of materials, especially for electronic-grade chemicals, ultra-clean polymers, etc. Their production equipment and pipelines must be both corrosion-resistant and polished, clean and residue-free. For highly corrosive materials (ph less than 5), PTFE-lined pipes are conventionally designed, while for mildly corrosive materials (ph around 6-7), many projects are designed as PTFE-lined pipes. However, the lined pipes are normally 2m / section, with many sections and two-end flange connections. The flanges will have W-shaped gaps that cause residues, affecting cleanliness. For this reason, we propose a construction process for a clean material production line using EP pipes. Summary of the invention

[0003] The object of the present invention is to provide a construction process for a clean material production line using EP pipes to solve the problems raised in the above background technology.

[0004] To achieve the above object, the present invention provides the following technical solution: A construction process of a clean material production line using EP pipes, comprising the following steps:

[0005] S1: Change the material of the discharge pipeline from 304 steel lined with fluorine to EP pipe;

[0006] S2: The connection between pipelines adopts automatic welding;

[0007] S3: EP pipes were filled with PVDF emulsion and placed outdoors in the sun for 2 weeks;

[0008] S4: The 316L stainless steel tube is electropolished, then cut into standard specimens and put into the salt spray test machine for testing.

[0009] Preferably, in step S4, the temperature in the salt spray tester is set to 35°C, the salt solution concentration is 5%, the pH value is between 6.5-7.2, and the salt spray deposition is controlled at 1.0-2.0 ml / (80 cm 2 / h), the sample placement angle is 15-30°, and the test time lasts for 200 hours.

[0010] Preferably, the automatic welding method in step S2 adopts argon arc welding, selects parameters such as welding current, voltage, welding speed, and selects welding materials such as welding wire and welding rod that match the material of the EP pipe, ensures that the welding site environment is clean, and avoids dust, oil pollution and other factors during automatic welding operations.

[0011] Preferably, in step S3, the EP pipe coated with PVDF emulsion is placed on an outdoor drying rack for natural drying, and the drying angle needs to be adjusted after a period of time.

[0012] Preferably, the EP pipe in step S1 is a 316L EP pipe.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention adopts 316L EP pipe, which has excellent corrosion resistance, and the surface is polished to be smooth and flat, which reduces the roughness of the inner wall of the pipe, reduces fluid resistance and dirt deposition, and improves the transmission efficiency of the fluid. The automatic welding technology is adopted, and the automatic welding has good quality and high efficiency, saves construction costs, and the internal pipe is clean and smooth without residue, thereby improving the product yield. DETAILED DESCRIPTION

[0014] The following will combine the contents in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] Example 1

[0016] In the clean material production line, clean conditions are required for automatic feeding of polymerization reactors, high-pressure reaction, low-pressure discharge, cleaning, separation, drying, transportation, and packaging. The clean pipeline from the polymerization reactor to the condensation barrel in the low-pressure discharge section has a diameter of DN100 and DN150. The original design was a PTFE-lined pipeline flange connection. The length of 6 reactors is 180m, and there are about 130 flange connection ports in a single line, totaling 780 flange ports. This will cause residues in the emulsion transportation. At the same time, the flow rate of the emulsion pipe is not smooth, and demulsification will occur. Considering that the medium in the pipe is an emulsion with a PH of 6 to 7, and the section of the pipe will be flushed with pure water after each discharge, the time interval of the emulsion in the pipe is within 7 days. To address this problem, we propose a construction process for a clean material production line using EP pipes, including the following steps:

[0017] S1: Change the material of the discharge pipeline from 304 steel lined with fluorine to EP pipe. The EP pipe is 316LEP pipe, that is, 316L stainless steel external polished pipe, which has good corrosion resistance. The surface is polished and has the characteristics of smoothness and flatness, which reduces the roughness of the inner wall of the pipe, reduces fluid resistance and dirt deposition, and improves the transmission efficiency of the fluid. Due to the corrosion resistance and mechanical strength of 316L stainless steel, the EP pipe has a long service life and reduces the frequency of maintenance and replacement;

[0018] S2: The connection between pipelines adopts automatic welding, which adopts argon arc welding. The parameters such as welding current, voltage and welding speed are selected. Welding materials such as welding wire and welding rod that match the material of EP pipeline are selected. The welding site environment is ensured to be clean and tidy, and dust, oil and other factors are avoided for automatic welding operation. Automatic welding has good quality, high efficiency and saves construction cost.

[0019] S3: EP pipes are filled with PVDF emulsion and placed outdoors in the sun for 2 weeks. The EP pipes coated with PVDF emulsion are placed on outdoor drying racks for natural drying. The drying angle needs to be adjusted after a period of time. After drying, the inside of the EP pipes soaked in PVDF emulsion is clean and smooth without residue, which improves the product yield;

[0020] S4: Electrolytically polish the 316L stainless steel tube, cut it into standard samples, and put it into a salt spray tester for testing. The temperature in the salt spray tester is set to 35°C, the salt solution concentration is 5%, the pH value is between 6.5-7.2, and the salt spray deposition is controlled at 1.0-2.0ml / (80cm 2 / h), the sample placement angle was 15-30°, and the test time lasted for 200 hours. After 200 hours (equivalent to 3 years) of salt spray test, the 316L stainless steel pipe sample treated with electrolytic polishing had only very slight corrosion marks on the surface. Through microscopic inspection, it was found that the oxide film on its surface still maintained good integrity, effectively blocking the erosion of salt spray. However, under the same test conditions, the comparison sample without electrolytic polishing showed obvious corrosion in less than 100 hours, and more rust spots and corrosion pits appeared on the surface.

[0021] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A construction process for a clean material production line using EP pipes, characterized in that: The steps include: S1: Change the material of the discharge pipeline from 304 steel lined with fluorine to EP pipe; S2: The connection between pipelines adopts automatic welding; S3: EP pipes were filled with PVDF emulsion and placed outdoors in the sun for 2 weeks; S4: The 316L stainless steel tube is electropolished, then cut into standard specimens and put into the salt spray test machine for testing.

2. According to claim 1, a construction process for a clean material production line using EP pipes is characterized in that: In step S4, the temperature in the salt spray tester is set to 35°C, the salt solution concentration is 5%, the pH value is between 6.5-7.2, and the salt spray deposition is controlled at 1.0-2.0ml / (80cm 2 / h), the sample placement angle is 15-30°, and the test time lasts for 200 hours.

3. According to claim 1, a construction process for a clean material production line using EP pipes is characterized in that: The automatic welding method in step S2 adopts argon arc welding, selects parameters such as welding current, voltage, welding speed, and selects welding materials such as welding wire and welding rod that match the material of the EP pipe, ensures that the welding site environment is clean, and avoids dust, oil pollution and other factors during automatic welding operations.

4. The construction process of a clean material production line using EP pipes according to claim 1 is characterized in that: In step S3, the EP pipe coated with PVDF emulsion is placed on an outdoor drying rack for natural drying, and the drying angle needs to be adjusted at regular intervals.

5. According to claim 1, a construction process for a clean material production line using EP pipes is characterized in that: The EP pipe in step S1 is a 316L EP pipe.