Long Distance Pipeline Construction Process And Key Points

In recent years, the construction of long-distance pipeline in our country has been greatly developed, and the construction technology and technology of long-distance pipeline have been rapidly improved, because most pipelines are buried underground, it is not easy to find the danger in operation, therefore, we must ensure the construction quality of long-distance pipeline project, and grasp the key points in the engineering process to ensure the quality of the project. This paper analyzes the construction key points in each process of long-distance pipeline construction, which plays a positive role in understanding the construction technology of long-distance pipeline and managing the construction quality of long-distance pipeline.

Pipeline construction process: Measurement and pay-off, removal of obstacles, detection of underground obstacles, repair of construction work belt and road, open digging pipes, anti-corrosion edge of pipelines, prefabrication of pipe fittings, transportation of anti-corrosion pipes, on-site pipe distribution, pipeline assembly and welding, non-destructive testing, anti-corrosion repair and leak detection, pipeline trench, backfill,geomorphic recovery, traversing, pressure section connection, section purge, diameter measurement, section withstand pressure test, internal cleaning, inter-station communication, inter-station ball sweeping, inter-station pressure test, line installation and completion of three piles work acceptance.

In each process, several important links of pipeline construction should be strictly controlled, that is, the anticorrosion quality of the pipeline, the welding quality of the pipeline, the buried depth quality of the pipeline, the diameter measurement and pressure test quality of the pipeline are well controlled, and the quality of the entire project can be guaranteed. Therefore, every process of pipeline construction should be carefully done, so that the previous process serves the next process, and the previous process provides guarantee for the smooth construction and quality of the next process.

1，Anti-corrosion insulation of pipelines

Pipeline anti-corrosion insulation is an important link in pipeline construction, and its quality is related to the safe operation, service life and operation and maintenance cost of the pipeline. Good anti-corrosion quality, long use year, less maintenance costs.

The anti-corrosion insulation of pipelines is carried out independently in the embalming plant designated by the owner and is the responsibility of the owner's full-time supervisor. The quality of each part of the anti-corrosion pipe section should meet the requirements of the anti-corrosion quality standard, and the factory should have a certificate.

2，Pipe assembly and welding

The quality of pipeline assembly is the premise of ensuring the quality of weld.

Before the pipeline group, the pipe should be cleaned, the oil and rust within the 20mm range of the pipe end and the groove should be cleaned, exposing the metal luster, and there should be a special person or supervisor responsible.

After the pipeline group is set up, after the inspection gap, wrong edge, etc. are qualified, and approved by the supervisor, the pre-welding is immediately preheated. Medium frequency heating or flame heating can be used for preheating, and the heating should be uniform.

The welding process of pipeline is the most laborious and most invested process in pipeline construction, and it is also the most critical link in pipeline construction.

Before pipeline construction, welders should be targeted training, training should have welding technicians and skilled welding technicians guidance, theoretical and practical welding operation training, to obtain welder certification. The welder who has obtained the certificate must pass the supervision examination to obtain the pipeline welding certificate on the site, and only the welder who has obtained the job certificate can participate in the pipeline welding work.

Qualified welders shall conduct assessment tests of various welding processes according to the welding operation instructions. After passing the assessment, welding process regulations for various welding tasks shall be formulated according to the welding process assessment, and submitted to the Supervision Department for approval to guide the on-site welding work, it must be strictly implemented and cannot be changed at will. Welding procedure to cover the whole assembly welding requirements and quality standards.

3, Nondestructive testing

The non-destructive inspection of the weld bead is carried out independently by a third party, which is responsible for the supervisor and the owner.

In the past, the pipeline construction, their own welding, their own inspection, resulting in inspection with subjective consciousness, no strict. The inspection results shall be examined by the supervisor, who shall inform the construction unit of the results. If the inspection fails, to be repaired or cut and rewelded. The construction unit must obey.

4, Anti-corrosion repair and leak detection

The anticorrosive personnel shall be trained, and the anticorrosive patch shall be constructed by the personnel who have passed the supervision examination and issued the work certificate. The repair material must be certified and qualified before it can be used. The welding joint that must be anticorrosive and insulated must be qualified by sand blasting, and the corresponding grade must be reached if the rust is removed by a wire brush. The repaired welding joint shall be qualified by the EDM leak detector inspection, the appearance inspection is qualified and the supervision inspection is approved. At the same time, we need to do a peel test. The test should be made up again if it fails.

The welding anticorrosive coating outside the pipeline should be checked by EDM one by one. The detected leak points should be marked and repaired with qualified repair materials to achieve the EDM leak detection qualification. The heating of the patch should be uniform and reach the required temperature, which should be measured with a point thermometer, and the record of the patch and the wound should be made.

The smooth acceptance of completion depends on complete completion materials and qualified construction quality. Therefore, in the construction of each process must be done in strict accordance with the requirements, to ensure quality, and have real and complete original information. If the original data is not complete, the completion data can not be sorted out, and the neglect of some processes and the lack of strict requirements often cause many problems left over from the completion and acceptance. This is something that needs special attention in the future.