RU2701652C1 - Method of dismantling a pipeline for decommissioning or for repair purposes - Google Patents

Abstract

FIELD: transportation.

SUBSTANCE: invention relates to pipeline transport, namely, to technologies for dismantling of decommissioned pipelines subject to repair and / or replacement. Method of pipeline dismantling includes soil opening to upper generatrix of pipe, pipe cutting and transportation of pipe to place of storage. After the soil is exposed to the upper pipe generatrix, the pipe is marked for sections with the length defined by the permitted load-lifting mass of the pipeline for its transportation with special-purpose equipment. Then process holes are cut out in marked places. In each hole soft reservoir is lowered with air permeability in the area of sides from 50 to 1,000 dm³/(m²⋅c), made of synthetic material and maximally approximated in size to internal size of pipe, and foamed polyurethane is supplied into soft reservoir to create sealing plug. After that, pipe is cut along center of formed sealing plugs and transportation of pipe to storage place.

EFFECT: disclosed is a method of pipeline dismantling.

1 cl, 1 dwg

Description

The invention relates to pipeline transport, and in particular to technologies for decommissioning decommissioned, subject to repair and / or replacement of pipelines, for example, oil product pipelines, pipelines intended for heating and water supply, outdoor sewage in places of passage.

Dismantling of decommissioned, subject to repair and / or replacement of pipelines - a set of technical measures aimed at removing the pipeline from the soil, cutting into parts and transporting pipes to the storage location (OST 153-39.4-027-2002).

The pipeline to be decommissioned must be prepared for dismantling. Preparation consists in freeing the pipeline from oil, cleaning the pipe cavity from dirt and paraffin of tarry, calcareous, silty, saline and other deposits.

Pipelines decommissioned and put into a safe condition do not require preparatory work, so they must be disconnected from neighboring sections, emptied and cleaned of transported products.

As a rule, during the cleaning process, it is not possible to completely free the pipeline from oil product residues and other deposits, which during pipe dismantling leads to product outflow and pollution of the surrounding soil.

No other harmful factor can be compared with the spills of oil and oil products - the raw materials of petrochemical processes - in terms of the extent of distribution and the number of sources of environmental pollution.

The elimination of spills of various petrochemical products is an urgent problem.

In such cases, soil contaminated with oil products is reclaimed, especially in marshy and waterlogged areas, which is a laborious and expensive process.

Therefore, one of the most important tasks is to prevent spills of various petrochemical products.

Known methods and devices for dismantling oil pipelines.

There is a method of opening a trench and lifting an underground pipeline during major repairs of main pipelines or when dismantling decommissioned inactive pipelines. The method includes loosening and removing vegetable and mineral soil backfill, raising the pipeline and laying it on the soil surface along the axis of the trench, moreover, loosening and removing vegetable and mineral soil backfill is carried out simultaneously with moving the multi-row trolley suspension and lifting the pipeline with cultivators attached to the tractors (RF Patent for invention No. 2389930, priority date 03.24.2008).

A known method of repairing a pipeline (RF patent No. 2332610, dated 22.12.2004), which can be used in the operation and repair of the linear part of the main pipelines. The proposed method consists in examining a pipeline with the location on the locality of the pipeline section being repaired, dismantling it and constructing a new pipeline section, while inspecting the pipeline, the section to be repaired before identifying it on the local area is determined as a section of the pipeline predisposed to corrosion cracking of pipes under KRC voltage, which discover by finding the zone of intersection of the pipeline with the watercourse, opening the pipeline with a hole, starting from the intersection zone, in opposite directions from the center of the watercourse and revealing at the same time in the open pit diagnostic signs of the occurrence of SCC, which are the presence of gleying of soil around the pipeline, the presence of delamination of the insulation coating of the pipeline, the presence of more than 10% siderite in the total mass of corrosion products under insulating coating of the pipeline. In the places where the detection of the indicated diagnostic signs in the open pit has ceased, the boundaries of the section of the pipeline predisposed to SCC, which are considered as the boundaries of the repaired section of the pipeline, are established. Then, the repaired section of the pipeline is dismantled within the established boundaries, in which a new section of the pipeline is constructed by erecting an elevated passage of the pipeline or by laying it below the boundary of the penetration of the watercourse into the ground.

The well-known "Method of sealing a pipe cavity using a clay swab and device for its implementation" (RF patent No. 1832879 from 04/07/1989, publ. 03/20/1996).

The invention relates to methods for pipeline transportation of liquid products, in particular petroleum products, and is intended to block the cavity of the pipeline during emergency and scheduled repairs. The device comprises a cap, a loading removable quick-detachable container mounted on a mechanized jaw grip, through which the device is mounted on the free ends of the pipeline after cutting the defective area. The maxillary grip has an upper non-rotatable and a lower rotatable jaw, forming an airtight cavity when a pipeline closes.

Clay is supplied to the pipeline cavity via an elbow tap installed on the upper jaw of the mounting unit, due to the force developed by the cap hydraulic cylinder. The complete assembly is mounted on a boom of a material handling vehicle.

Disadvantage: the method and the device are designed to block the cavity of the pipeline during emergency and scheduled repairs. The device is very bulky and expensive.

It is known "Device for sealing the internal cavity of the pipeline" SU No. 1643852 from 05/30/1988, publ. 04/23/1991).

A device for sealing the internal cavity of the pipeline contains a polyurethane foam swab and a channel for introducing the composition of the polyurethane foam into the pipeline. What is new in the device is that the tampon is a cylinder turning into a truncated cone, while a groove is made in the cylindrical part of the tampon, in which two channels are diametrically opposed along the generatrix — a channel for introducing the polyurethane foam composition and a channel for removing gases generated in the process foaming polyurethane foam, the inner part of the tampon is hollow and has the shape of a cone, the base of which is the end face of the tampon, and the diameter of the tampon is less than the diameter of the sealed tube water.

Disadvantage: this device is used to temporarily seal the pipeline.

Also, from US Pat. No. 3,310,615 (priority of March 21, 1967), a method is known for sealing abandoned pipelines located underground related to the supply of water, gas, fuel, and also for telephone cables, where the cables do not completely fill the internal cavity of the pipelines.

The aim of the invention is to provide an easily performed method of sealing pipes underground, using a minimum amount of material to obtain a sealing plug with high adhesive properties, as well as reducing the amount of equipment needed to seal a pipe located underground. Moreover, the resulting foam material must harden and have adhesive properties.

The sealing plug can be made of any combination of synthetic resins in the form of two components that, when mixed, form a foam, such as polyurethane, epoxy resin, polyvinyl chloride, urea-formaldehyde resin and others.

To reduce the amount of material to obtain a sealing tube use a container of flexible material, for example polyethylene, consisting of a pocket part oriented to the sides and the open upper part in the form of a pipe.

The disadvantage of the above method is that when using such a container when creating a sealing tube inside a soft reservoir, cavities with gas arise, for example, resulting from the production of a sealing tube from polyurethane foam. Such cavities filled with gas prevent the tight fitting of the sealing plug to the inner walls of the pipe, which must be removed, which can lead to leakage of the substance in the pipe after it is cut.

Known methods of dismantling disabled pipelines using devices for sealing the internal cavity of the pipeline are ineffective and labor-intensive.

Currently, the dismantling of oil pipelines is carried out in accordance with OST 153-39.4-027-2002.

The closest analogue of the claimed invention is a method of dismantling a decommissioned oil pipeline described in patent RU 2585158 (priority from 04/16/2015).

The method includes opening the soil to the upper generatrix of the pipe, cutting the pipe and its transportation. After opening the soil to the upper generatrix of the pipe, the dismantled pipe is marked up in sections of a length determined by the permitted carrying capacity of the transport for its transportation. Then, technological holes are drilled in marked places through which excess pressure is removed in the pipeline. After that, polyurethane foam (PUF) is fed into the internal cavity of the oil pipeline to create sealing "plugs" in all marked places, the pipe is cut in the center of the formed plug. In this case, the length of the sealing plug when polyurethane enters is at least 1 meter, or until the pipe hole is completely filled with the length necessary for sealing.

The disadvantages of this method are the possible draining of liquid PPU from the working area before the start of the chemical reaction due to the tilt of the pipe and the inability to fix the sealing plug in the desired sealing location, as well as the inability to create a sealing plug from PUF (polyurethane foam) of optimal size.

The aim of the claimed invention is to eliminate the disadvantages of the method described in patent RU 2585158.

The technical task of the invention is to prevent runoff of liquid PPU from the working area before the start of the chemical reaction due to the tilt of the pipe, fixing the sealing plug in the desired sealing location and creating a sealing plug of PPU (polyurethane foam) of optimal size.

The technical result is to increase the tightness as a result of creating a sealing plug made of polyurethane foam of the optimal size, preventing the liquid PUF from draining from the working area before the chemical reaction due to the pipe tilt, and reducing the loss of sealing material when receiving a sealing plug.

The achievement of the technical result is ensured by the fact that for supplying polyurethane foam (polyurethane foam) into the pipe section of the pipeline prepared for dismantling, a soft reservoir made of synthetic material is lowered, which is then filled with polyurethane foam, the synthetic reservoir material has air permeability of 50 to 1000 units (dm3 / (m2 * c) sufficient for passing through it the gases generated as a result of the formation of polyurethane foam, for a certain grade of polyurethane foam, to prevent the formation of air cavities inside the “plug”.

This is due to the fact that when using a soft reservoir made of synthetic material with an air permeability of less than 50 units (dm3 / (m2 * s), when creating a sealing plug inside the soft reservoir, cavities with gas appear that prevent the sealing plug from snugly adhering to the inner walls of the pipe to be dismantled. of this, after cutting the pipe, spillage of oil product residues or deposits inside the pipe to be dismantled through air cavities resulting from gas accumulation may occur in.

Moreover, areas with air permeability from 50 to 1000 units (dm3 / (m2 * s) are located in the area of the sides of the soft reservoir, which ensures a uniform exit of gases from the reservoir into the pipe, without creating air bubbles from above and below.

In general terms, the claimed method of dismantling the pipeline for decommissioning or for the purpose of repairing it involves opening the soil to the upper forming pipe, cutting the pipe and transporting the pipe to the storage location, and after opening the soil to the upper forming pipe, the pipe is marked into sections with a length determined by the allowed lifting weight of the pipeline for transportation. Then, technological holes are cut out in the marked ones, into each of which a soft reservoir with air permeability in the region of the sides from 50 to 1000 dm ³ / (m ² ⋅ s) is lowered, made of synthetic material and as close as possible to the internal size of the pipe, and served Inside the soft reservoir, polyurethane foam is used to create a sealing plug, after which the pipe is cut in the center of the formed sealing plugs and the pipe is transported to the storage location.

The implementation of the method of dismantling the pipeline for decommissioning or in order to repair it.

The preparation of the pipeline for dismantling consists in ensuring conditions that exclude the spill of oil products and paraffin of tarry, calcareous, silty, salt and other deposits from the cavity of the pipeline and increasing the rigidity of the pipe to prevent fractures.

The dismantling method includes the following process steps:

- opening the soil to the upper generatrix of the pipe,

- cutting into pieces,

- transportation of pipes to the storage location.

Before cutting the pipe into parts, it is necessary to carry out the following actions before transportation. These actions are aimed at sealing those sections of the pipe where it will be cut, in order to prevent spillage of oil product residues during transportation of pipes after their cutting.

For this:

- they mark the pipeline into sections of a certain length along which the pipe will be cut;

- cut openings for supplying foam in the cavity of the pipe;

- place a soft tank of synthetic material (technological bag) in the cavity of the pipe, the soft tank is as close as possible to the internal size of the pipe and long enough to seal the pipe.

- serves polyurethane foam in a soft reservoir of synthetic material;

- carry out pipe cutting;

- lift and lay the pipe for transportation.

The dismantled pipe is marked into sections of a certain length along which the pipe will be cut. The number of sections and its length into which the pipeline will be divided is calculated mathematically, taking into account the condition that the mass of one section should not exceed the permissible load-lifting mass for its transportation by special equipment to the prepared site.

The mass of one section of the pipeline should not exceed the permitted lifting weight of the conveyor.

The mass of one meter of pipes for general use, manufactured by the outer diameter, wall thickness and length, is calculated by the formula:

m = π * (ds) * s * ρ * 10 ^-6 ,

where m is the theoretical mass of one linear meter of pipe, kg,

π = 3.14 (constant value),

d is the outer diameter of the pipe, mm

s is the wall thickness, mm

ρ is the density of the pipe material, g / cm ³ .

The maximum length of the pipe section must not exceed 100 meters.

Sealing the internal cavity of the PPU pipelines should be carried out in accordance with the following technology.

Then, holes are cut out in marked out places for supplying the PU foam. A soft reservoir of synthetic material (bag) is lowered into it. The characteristics of the material of the soft reservoir are described above.

Polyurethane foam (PUF) is fed through a hole into a soft reservoir of synthetic material to form a cork. Under the influence of an internal chemical reaction, an increase in the volume of the injected polyurethane foam occurs, the bag’s internal volume is completely filled, the bag snugly adheres to the inner walls of the pipe and the cork thus formed hardens further.

The purpose of using a soft reservoir made of synthetic material is to accurately position the stopper in the marked places, to save the consumption of PPU components, and to prevent the displacement of the PPU tube when working on slopes.

The volume of supplied PPU is calculated depending on the diameter (radius) of the pipeline.

The amount of polyurethane foam (PUF) for the formation of one sealing plug in the cavity of the pipeline is calculated by the formula:

M = m _PPU + m _p

where M is the amount of polyurethane foam required for the manufacture of one cork, kg;

m _p - the mass of losses, which is from 30% to 50% of the estimated mass of polyurethane foam, kg, but in this case, when using a soft reservoir, this indicator is not taken into account, because the volume is limited by a soft reservoir.

m _PPU - estimated mass of polyurethane foam, kg.

m _PUF = ρ * V

where ρ is the density of polyurethane foam, kg / m ^{3 it was} experimentally obtained that the density should be at least 15 kg / m3, in order to create a dense tube structure, the density was taken to be 30 kg / m3;

That is, the amount of polyurethane foam (PUF) for the formation of one sealing plug in the cavity of the pipeline in this case is calculated by the formula:

M = m _PPU .

V is the volume of the pipeline section that needs to be foamed, m ³ .

V = π * r ² * b

r is the radius of the pipeline, m;

b - the length of the section of the pipeline, which must be foamed, m;

π = 3.14 (constant value).

An example of a specific implementation of the method of dismantling a decommissioned oil pipeline.

An example of calculating the required number of PPU plugs and raw materials for their manufacture for a pipe with a diameter of 219 mm and a length of 3 km.

1. The volume of the pipeline section is determined (0.5 meter long), the obtained length was calculated empirically, for an example of calculation, for each diameter the length will be different, which must be foamed:

V = π * r2 * b = 3.14 * 0.1095 ^∧ 2 * 0.5 = 0.0188 m ³ .

2. The mass of raw materials required for 1 (one) cork, 0.5 meters long, is calculated:

m _PUF = ρ * V = 30 * 0.0188 = 0.564 kg, for ideal temperature conditions, i.e. ambient temperature from + 15C and above and humidity 80%; for another ambient temperature, a coefficient of temperature dependence is introduced into the calculation, which is determined for each specific brand of PPU.

4. The weight of 1 meter of this pipe according to the assortment table is 41.63 kg, and the carrying capacity of the mechanism is 10 tons, it follows that the length of the pipe section that the mechanism can lift will be:

10000: (41.63 + 1.7) = 230.79 m.

Given that the maximum length of the pipe section should not exceed 100 meters, the number of such sections along the length of the pipeline will be equal

3000: 100 = 30 pcs.

5. For 30 sites, 31 PPU plugs are needed, for the manufacture of which 31 * 0.564 = 17.484 kg of raw materials are needed.

Forming sealing plugs from polyurethane foam in all marked areas of the pipeline.

After the formation of sealing plugs, the pipe is cut.

Pipe cutting is carried out in the center of the formed cork (i.e. half its length).

After cutting, the edges of the pipeline remain completely sealed, product residues in the pipe cavity are transported to the storage location.

Thus, to prevent product spills from a decommissioned pipeline for a 3 km pipe, only 17.484 kg of polyurethane foam is required, which is much cheaper when compared with the harm of environmental pollution.

Schematically, the filling of the pipe of the dismantled PPU pipeline is shown in figure 1.

Polyurethane foam from the complex for pouring polyurethane foam (4) through the sleeve for supplying sealing material (3) using a filling gun (5) is fed into a soft reservoir of synthetic material (6) located in the inner cavity of the pipe (1) of the dismantled pipeline to form a sealing a polyurethane foam stopper that prevents spillage of product residues (2), where parameter (b) is the length of the pipeline section that needs to be foamed.

The dismantling of the decommissioned pipeline of the claimed method allows to prevent spillage of product residues during transportation of pipes after cutting, which reduces the risk of environmental pollution.

In addition, the dismantling of a decommissioned pipeline by the claimed method is simpler and more effective in comparison with existing methods.

When dismantling a decommissioned pipeline, PPU was used to form sealing plugs inside the cavity of the emptied pipeline and to prevent spillage of the remains of transported products.

Compared with the known methods of dismantling pipelines, which work effectively only in favorable conditions with normal access roads, the inventive method is more simplified, since it uses mobile equipment and it is even possible to seal the internal cavity of the pipeline with two people.

Claims (1)

A method of dismantling a pipeline for decommissioning or for the purpose of repairing it, including opening the soil to the upper forming pipe, cutting the pipe and transporting the pipe to a storage location, in which, after opening the soil to the upper forming pipe, the pipe is marked up into sections of length determined by the permissible lifting weight pipeline for its transportation, then technological holes are cut out in marked out holes, into each of which a soft reservoir with air permeability in the region of the sides from 50 to 1000 dm ³ / (m ² s), made of synthetic material and as close as possible to the internal size of the pipe, and polyurethane foam is fed into the soft reservoir to create a sealing tube, then the pipe is cut in the center of the formed sealing tubes and transported pipes to the place of storage.

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