EA045161B1 - METHOD FOR CLEANING THE INTERNAL CAVITY OF A PIPELINE - Google Patents

Description

Field of technology

The present invention relates to a method for cleaning pipelines, such as air ducts, pipelines or process pipelines in the oil and gas industry. Cleaning is particularly suitable for removing contamination generated during pipeline construction and installation, before putting the pipeline into service or before closing a section, for example by installing valves inside the pipeline.

The essence of the invention

When installing pipelines, including associated components such as main pipe branches, release valves, meters or associated control equipment, such activities may be performed either on the industrial site or in a factory from where the assembled section of pipeline or pipe section is transported to the industrial site. Despite the fact that the latter option of transporting a section from one point to another has its difficulties, the advantage of this method is that it reduces the amount of welding work on the industrial site, which can often be more complex than in a factory environment. Moreover, the plant usually has instrumentation available to test pipe sections before sending them to production sites, which improves the quality of control.

However, when sections of pipeline in either of the two options presented are welded together on the job site, contaminants can accumulate within the pipeline. Contaminants must be removed before the pipeline is finally put into service because contaminants may be introduced into the fluid flowing through the pipeline. In addition, straight-through valves can be damaged if contaminants get inside the valve. It is therefore important that the piping/process piping is cleaned before use.

Currently, once welding in a pipeline is considered complete, water is used to test the partially assembled pipeline. However, there are certain problems with this. Firstly, such tests require a sufficient amount of water. Secondly, the release of water into the environment is unacceptable due to the possible toxicity of welding materials. Thirdly, the water itself will need to be removed, again to avoid contamination of the liquid flowing inside the pipeline. Additionally, using water to flush piping systems introduces contaminants into the operating valve system and static equipment. Water, if not treated with the correct corrosion inhibitors, can accelerate corrosion in the piping system.

Also, a disadvantage of modern cleaning methods is the inability to control the quality of cleaning, even if the operating organization has carried out the cleaning. After testing in the above manner, the water removal step follows. The system is now in the pre-commissioning phase, during which it is being tested. This check is carried out using a camera that moves along the pipeline. Cleaning of clogging areas and possible areas of oxidation is carried out by hydro-jet cleaning and cleaning crews. After the water from the hydro jetting has settled, further camera testing is carried out. Next, at the cleaning and inspection stages, the system is monitored, where the quality of cleaning and the condition of the internal cavity of the pipeline are checked. Residual hydrojet water is removed by draining from valves and piping sections to support the water removal procedure. All dismantled valves and sections are installed in place, equipment is connected to drain the system and evaporate water. Next, a final assessment of water damage and contamination to the carbon steel pipeline is performed and, if necessary, chemical cleaning operations are performed depending on the oxidation damage. The pipeline is then handed over to the customer for commissioning.

In the above cleaning methods, the ability to check the quality of cleaning is also very limited; in some cases, only 30% of the surface can be checked. The process described here allows the pipeline to be cleaned and inspected piece by piece, allowing 100% access and therefore providing 100% recorded inspection videos that prove the piping system is 100% clean, dry, free of contamination and blockages.

The purpose of the present invention is to provide an improved method for cleaning process pipelines, air ducts and piping systems.

Summary of the Invention

According to the invention, a method is proposed for cleaning the internal cavity of a pipeline, which includes the steps:

selecting a pipeline section to be cleaned, determining a pipeline control point, installing a cleaning device at the entry point of a pipeline section, a device connected to a fluid source and equipped to blow liquid along the pipeline section from the first or last holding point to the entry point, device, further including image recording means for obtaining a video recording of the interior of the pipeline, installing the device into the pipeline until the device reaches a control point,

- 1 045161 securing the manifold at the entry point to collect contaminants blown from the pipeline, activating the compressed air supply, moving the device from the holding point to the entry point to blow contaminants towards and into the manifold, stopping the fluid supply, dismantling the manifold with the contaminants removed from the entry point, dismantling the device from the pipeline, analyzing images of the cleaned pipeline, if the condition of the internal cavity is satisfactory, issuing a certificate confirming the suitability of the pipeline section.

In this way, effective cleaning is successfully carried out, as well as verification to confirm the results and certification of the cleaning performed.

The optionally selected device includes a light source to enhance the quality of the resulting images.

It is recommended to supply flushing liquid at a pressure of 5 to 12 bar/g, then 5 to 10 bar/g is recommended, and to remove contamination in the pipeline system, a pressure of 7 bar/g is recommended. However, the speed of movement should not cause damage to the pipeline.

It is recommended that the flushing liquid be selected from one or a mixture of several components: compressed air, nitrogen gas, water, cleaning solutions, for example, containing surfactants and preservatives, especially preferably compressed air.

If required, before pipeline construction begins, a diagram will be drawn up showing the location of control points within the pipeline as it is being built. This allows for effective cleaning of the entire constructed pipeline. The diagram is easily implemented using software, optionally using a tablet or similar device, and is additionally conveniently linked to images and other pipeline data.

Optionally, as the device moves from entry point to control point, checks are performed to identify elements that may restrict the device's passage. This check can be done visually using a camera.

Codes (QR) and/or barcodes are optionally affixed to the pipeline element to facilitate identification and origin of the element.

It is recommended that pre-installed valves in the pipeline be inspected and cleaned before cleaning the pipeline, as such valves can become contaminated due to the nature of the pipeline construction process.

It is recommended to carry out anti-corrosion treatment with the device where necessary, in sections of the pipeline, for example, where areas are affected by corrosion.

Where there is a main manifold and branches from it in the pipeline, the manifold is cleaned first, then the branch. This can sometimes be done by pushing the contaminant from the branches into the main manifold and then finally cleaning the manifold.

Brief description of drawings

The invention is accompanied by drawings, which show, as an example, only one version of the pipeline cleaning method:

in fig. 1 shows two sections connected together;

in fig. 2 shows an additional section;

in fig. 3 shows sections welded together;

in fig. 4 shows a pipeline/process pipeline welding test;

in fig. 5 shows the beginning of the inspection of a welded pipeline/process pipeline;

in fig. 6 shows an inspection of a welded pipeline/process pipeline;

in fig. 7 shows cleaning and inspection;

in fig. 8 shows the cleaning of the next section of pipeline/process piping;

in fig. 9 is a flowchart illustrating the cleaning method.

Detailed Description of the Invention

The present disclosed invention relates to pipelines, including partially constructed pipelines, after welding one or more sections. In a typical welding process, which is known and used in the art, the sections are lifted into position and supported on pipe supports. To ensure a uniform distance between sections at the welding stage, additional section parts are used, which are attached with special fastening bullets. The distance between the bullets is welded by welding the root of the seam. The first bullet is removed using a grinder and the edge of the first weld is also ground to become the leading edge for the second weld. The two steps described are repeated when connecting sections until the welding is completed.

In this invention, the steps described above are repeated until a control point is reached, which is determined by the cleanliness criteria established before welding. An inspection device, which consists of a chamber and an air jet, is installed to remove contamination from the structure and dry the section. The inspection is completed based on images from the camera. If necessary, an internal corrosion inhibitor is applied and identification means, such as tamper tapes, are added to visually confirm that the inspection has taken place. This procedure is repeated until the next checkpoint until the system or part of the system is built. Then you can carry out hydraulic tests and move on to the water removal stage. Since contaminants have already been removed and corrosion-prone areas have been protected with a corrosion inhibitor, the system can be handed over to the operator more quickly with certification to be free of contamination and serviceable than with prior art methods.

The construction and cleaning process is shown in Fig. 1-7, in which piping/process piping section 5 is formed from sections 10, 20, 30. It should be understood that piping/process piping section 5 shown is only part of the piping/process piping system. In fig. 1 shows two tubular sections 10, 20, which, for example, have been transported from a remote site, placed in a position where the free ends of each remain adjacent and in contact with each other, prepared to be joined together by welding. In fig. 2, a third section 30 is also located adjacent the free end of section 20. Thus, the three sections form a continuous pipeline from the first end 15 of section 1 to the second flanged end 35 of section 30. Sections 10 and 20, and sections 20 and 30 are then prepared by grinding and welded to each other in the usual way to create welded joints 40, 41.

To introduce material into the pipeline, one of the common methods is used - the method of stripping the beginning and end of the tack to a sharp edge to perform the welding process, as shown in Fig. 3. At this stage, the rivets (bullets) for welding are also ground so that they can be removed from both sides of the pipe sections, allowing access to welding. Leading edges 42, 43 are formed in sections 10, 20 around the diameter of the free end of sections 10, 20. This allows the weld puddle to form more easily, which in turn allows weld metal to penetrate between the ends of sections 10, 20. Formation of leading edges 42, 43 and the very removal of the spacers results in the formation of metal particles that enter sections 10, 20, as shown in 44. Such metal particles can cause damage to valves and static equipment if the flow within the piping/process piping carries the particles there. In addition, some of the metal waste generated after grinding may get inside sections 10, 20, 30. Typically, when preparing for welding 10 inches (25 cm), about 3 g of abrasive waste can be generated in the pipeline.

After completing the welding work and forming the pipeline or process piping system, you can begin to check the tightness of the pipeline. One way to perform such a check is shown in FIG. 4. Water is pumped in a pipe. Pumping is also carried out under high pressure, monitoring the presence/absence of leaks. Thus, water is pumped through the first end 50, passed through sections 10, 20, 30 and released through the second end 55, from which it is collected for regeneration and/or reuse. The flow of water can remove some of the solids from the pipeline/process piping system. However, when the water supply is stopped, there is usually not only residual solid metal particles, usually larger particles, but also the water that was used for testing, which must also be removed.

The method presented in this work provides effective cleaning of pipelines, usually in sections ranging from 10 to 40 meters in length.

Thus, a visual dirty inspection is first performed using the device 60 as shown in FIG. 5. The device 60 is equipped with a chamber 61 at its front end and is capable of purging the pipeline with compressed air towards its rear part 62 using nozzles 63.

Optionally, the device 60 may also be equipped with a backlight to facilitate obtaining good quality images. A light source can be installed to illuminate the pipeline up to the control point. The operating pressure is selected according to the application and can range from 5 to 10 bar/g with a maximum pressure typically 12 bar/g (170 psi). However, the pressure can be increased accordingly. The pressure must be sufficient to ensure removal of contaminants at a reasonable rate, but not so excessive as to cause contaminant damage to the interior of the pipeline. A pressurized fluid supply (not shown), preferably selected from one or more of compressed air, nitrogen gas, water, cleaning solutions such as those containing surfactants and preservatives, particularly preferably compressed air, is connected to the device 60 to perform this function. You can also connect a light source to improve the quality of the resulting images.

The device 60 is inserted into the entrance 1 at the second end 55 of the section 30, then moved by pusher or robotic guides to the first end 50 of the pipe section 5, as shown in FIG. 6. As it moves, camera 61 allows video recording of the state of the internal cavity of section 5, which is transmitted to the operator’s phone. Thus, after cleaning, a comparison video can be made with the original condition of pipe section 5.

A collecting funnel 70 is attached to the second end 55 of section 5 which safely catches and retains material displaced from section 5 in the subsequent process. The collected material can subsequently be safely disposed of in a prescribed manner.

After installing the funnel and installing the device 60 at the first end 50, the liquid source is turned on. The apparatus 60 is slowly withdrawn from the section 5 towards the funnel 70. As the apparatus 60 is pulled out, water and remaining contaminants are blown towards the funnel 70 by compressed air exiting the nozzles 63. Preferably, areas that appear to have been corroded by water, can be treated with anti-corrosion treatment carried out by the device 60. The liquid/compressed air used should preferably be dry, should not contain oil, should be supplied at room temperature. In addition, air is supplied at a pressure of at least 7 bar and at a rate of up to 600 cubic feet per minute, providing an air velocity of approximately 657 cubic feet per minute (18.6 m ³ /in).

If the images demonstrate the proper condition of section 5, which meets the agreed criteria of the operating organization, then a report is drawn up and signed confirming the fact of cleaning and the satisfactory condition of section 5.

After signing the act in relation to section 5, the next section 75 is connected, which consists of sections 80, 90, 100, by connecting section 80 with the free end of section 30 of section 5. To connect the pipeline sections, it is necessary to weld sections 80 and 90 and pipeline sections 90 and 100, as well as sections 30 and 80, as a result of which pollution is formed. The device 60 is reinserted into the pipeline at the free end of section 100 and advanced to end 35 of section 30, the previously free end of section 5, which upon completion is designated as a reference point. Next, section 75 is cleaned according to the procedure described above for section 5.

Appropriate precautions must be taken before inspecting a specific section of pipeline. Before pipeline construction begins, pipe and instrumentation diagrams and isometric drawings are assessed.

The purpose of the assessment is to cover all natural ends of a section in the pipeline that may be inaccessible due to the number of bends in the section, valves with which the pipeline is equipped, etc. A set of control points are identified and marked on the diagrams and drawings so that construction of the pipeline section is stopped at the control point to allow inspection of the internal cavity as above before further assembly of the pipeline makes inspection impractical/unaffordable. Checking the diagram and marking the pipeline can be done using special software. The software and labeled drawings then provide a clear indication of where cleaning/inspection needs to be done. The software can also provide the operator/installer with real-time data on construction and cleanup progress. In addition, the location of the last red welds and installation welds can be specified, which will facilitate control during pipeline construction and installation.

Once a pipeline to be cleaned has been approved and cleared, items identified as likely to be damaged during the cleaning process are checked to ensure they are missing/removed. To ensure compliance with safety regulations during cleaning operations, personnel not involved in cleaning are not allowed into the piping system, and the area where cleaning is being carried out is marked with identification marks such as tape, signs, etc. Work on the pipeline is suspended.

The free end of the composite hose cable, connected at one end to the device 60, is connected to an oil-free dry air compressor or liquid supply pump. If necessary, additional sections of the air duct can be attached. Typically, select a hose with a diameter of 3/4" to 1 1/4" (1.9 to 3.2 cm) that is rated to handle more than the maximum pressure used. After checking the connection for leaks and if the hose is damaged, the air compressor/fluid pump starts. The air valve for supplying air to the device 60 is opened as soon as it is considered safe to do so.

The device 60 is then inserted until it reaches the reference point of the pipe sections. After installation of the device 60, a visual inspection of the condition of the internal cavity of the pipeline sections is carried out to record contaminants remaining during the construction process or subsequently moved into the sections, namely welding rods, welding bullets, sand and stones, etc. You can also see damage or oxidation of the metal, especially in the joint area. If oxidation or corrosion is detected, the device can also be used to apply corrosion inhibitor fluids.

Preferably, a funnel 70 is installed at the end of the section of pipeline into which the device 60 is inserted. The funnel 70 collects debris removed from the pipeline during operation of the device 60. As the device 60 moves through the pipe to the inspection point, inspections are also performed. It is recommended that a visual inspection be carried out using camera images to identify elements that may restrict access to the device 60. Valves, orifices, filters, etc. that have been removed prior to cleaning or that cannot be removed are provided with

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Claims (1)

a special code (QR) or identification tag with a barcode for the purpose of cataloging, including a photograph and other information (origin, installation date, etc.). Items removed from the system can be organized with labels, entered and registered in Asset Integrity software. In cases where the pipeline includes a main manifold from which branches extend, it is traditional to clean the manifold first and then the branches. The branches can usually be accessed. Contaminants from the internal cavity are blown into the main collector. The choice depends on the design. You can also clean the branches first and then the main collector. Once cleaning begins, device 60 is retracted from the control point back to the entry point. The removal rate is controlled, which makes it possible to prevent the accumulation of removed contaminants in front of the device, for example, around the chamber 61. Thus, the debris is blown out by compressed air to the entry point. When device 60 is removed, a visual inspection of the pipeline's cleanliness status is recorded for review by the pipeline operator or operating organization. If you find that debris remains, the process can be repeated. Once the device 60 reaches the entry point, the valve on the device closes and the compressed air is turned off. The device, connection and hoses are removed before transporting the device 60 to its next location. In fig. 9 summarizes an aspect of the method for cleaning the piping system 110. The compressed air produced in the air compressor 111 passes through a dryer 112 to remove moisture from the compressed air so that water does not subsequently enter the piping system 110. The dried air then passes in the line 114 to the distributor 113. comprising a hose reel which is connected to the rear of the device 60. The device 60 is then used to clean the piping system in the manner described above. Every piping system that is under construction or pre-assembled has an outlet/inlet port or flanged section removed to allow the last of the construction debris from the system to be removed from the system after the red completion weld has been completed. Access to this point is possible at a distance of 10 to 40 meters, depending on the pipeline configuration. It is important that in the internal cavity of the pipeline where the valves are installed, the cleaning direction (ie removal of the device 60) is carried out from the valve to a certain entry point. The device 60 is not used to blow contaminants through the valve, as this would pose a risk of damage. However, if this is the only access point, a vacuum unit can be used to suck contaminants out of the system and prevent debris from entering the valve operating element. All straight through valves must be cleaned. This means that the piping sections must be installed at an agreed distance from the valves, or ultimately contain a flanged section for access, cleanability, maintenance, or a section with top or bottom access for a drain or valve. The drain or valve must have a minimum inside access diameter of 3/4 inch (1.9 cm). Pre-installed valves in piping systems can be inspected and attempted to be cleaned. Based on the inspection and cleaning results, the certificate will indicate that the pre-installed valves have been inspected and partially cleaned. A record confirming the fact that the pipeline has been cleaned and its condition is saved and signed in real time, which increases efficiency. Thus, data on the cleaning carried out and the condition of the internal cavity of the system contains: a marked diagram of the pipeline and instrumentation, isometric drawings showing the pipeline during its cleaning, records of any large or unexpected objects removed, which allows improving the methods, a certificate confirming the satisfactory condition of the internal cavities and video. After this, the pipeline is ready for installation of the next section. CLAIM 1. A method for cleaning the internal cavity of the pipeline (5), including the following steps: selection of the pipeline section (5) to be cleaned; determination of pipeline control point (5); installation of a cleaning device at the entry point (1) into the pipeline section; the device is connected to a source of flushing fluid and is equipped to flush fluid in a direction along the pipeline section from the first or last control point to the entry point (1); a device further including image recording means for obtaining a visual record of the interior of the pipeline; inserting the device into the pipeline until the device reaches the control point; attaching a manifold (70) at the entry point to collect contaminants blown out of the pipeline, activating the compressed air supply; -