An online stress monitoring multi-point synchronous pipeline lifting method

Abstract

The application discloses an online stress monitoring multi-point synchronous pipeline lifting method and relates to the technical field of pipeline repair.The method comprises the following steps: S1, pipeline displacement calculation, which is combined with design drawings and on-site measurement to analyze and calculate the settlement displacement of the liquid inlet pipeline; S2, installation of a temporary limiting support, which is installed on the steel structure frame layer in front of the tank; S3, installation of a pipeline lifting bracket, which is installed on the steel structure bearing frame as the support point of the pipeline support hanger on the steel structure frame layer in front of the tank; S4, setting of pipeline lifting measures; S5, setting of pipeline lifting monitoring facilities, stress concentration positions are calculated through modeling, and monitoring points are set at positions with relatively large strain; and S6, pipeline lifting confirmation.The online stress monitoring multi-point synchronous pipeline lifting method solves the problem that the system is integrally displaced by multiple points with the same pulling force under the premise that the strain is controllable, can meet the repair of pipeline sag, saves cost and materials, improves efficiency, and protects the ecological environment.

Description

Technical Field

[0001] This invention relates to the field of pipeline repair technology, and in particular to a method for online stress monitoring and multi-point synchronous pipeline lifting. Background Technology

[0002] In existing technologies, buttress pipe supports containing residual liquefied natural gas (LNG) inside natural gas storage tanks are prone to sagging after a fire. Due to the extremely unique construction environment of natural gas storage tanks—with one-third of the tank still containing LNG and the overall working environment severely burned, and some pipelines still leaking—repair is difficult and risky. Current solutions often involve simply discarding the sagging, collapsed pipelines. This method is costly and environmentally harmful. Summary of the Invention

[0003] The purpose of this invention is to provide an online stress monitoring method for multi-point synchronous pipeline lifting, in order to solve the above-mentioned technical problems.

[0004] The technical solution adopted in this invention is as follows:

[0005] A method for online stress monitoring and multi-point synchronous pipeline lifting includes:

[0006] S1. Pipeline displacement calculation: Analyze and calculate the settlement displacement of the liquid inlet pipeline based on the design drawings and on-site measurements.

[0007] S2. Install temporary limit brackets. Install temporary limit brackets on the steel structure frame layer in front of the tank.

[0008] S3. Install pipe lifting brackets and install a steel structure load-bearing frame in the steel structure frame layer in front of the tank as the support point for pipe supports and hangers.

[0009] S4. Set up pipeline lifting measures, repair the buttress support steel structure of the pipelines on the first floor, the second floor and the third floor in sequence, and lift them with chain hoists;

[0010] S5. Install pipeline lifting monitoring facilities, calculate the stress concentration location through modeling, and set monitoring points at locations with large strain;

[0011] S6. Confirmation of pipeline lifting.

[0012] Preferably, in S2, the temporary limiting bracket is installed below the pipe insulation support and must not be in direct contact with the pipe.

[0013] As a preferred option, in S3, the installation of the steel structure load-bearing frame must be carried out in accordance with the requirements of the steel structure construction plan, and saddle supports need to be installed between the pipes and the steel structure load-bearing frame.

[0014] As a preferred embodiment, in S4, for each layer of pipe repaired, hanging chains are installed on the left and right sides of the pipe to share part of the pipe load. The upper part of the chain hoist is suspended on the steel structure of the buttress support of the corresponding layer, and the lower part of the chain hoist is tied and fixed to the pipe with slings.

[0015] As a preferred option, in S5, during the pipeline lifting process, displacement measurement points are set from the top valve position of the tank to the shut-off valve of the second-level platform in front of the tank in the unloading manifold, and a flange opening measurement point is set at the upper and lower liquid inlet pipe interface flanges.

[0016] As a further optimization, during the pipeline lifting process, multiple displacement measurement points are set at the unloading manifold from the top valve position of the tank to the shut-off valve of the second-level platform in front of the tank, and one flange opening measurement point is set at the upper liquid inlet pipe interface flange and the lower liquid inlet pipe interface flange.

[0017] As a further preferred option, in S6, the unloading manifold is lifted by using hydraulic jacks for jacking and chain hoisting assistance.

[0018] The above technical solution has the following advantages or beneficial effects:

[0019] The online stress monitoring multi-point synchronous pipeline lifting method provided in this invention solves the problem of overall system displacement with the same tension at multiple points under the premise of controllable strain. It can meet the repair of pipeline sagging, save costs and materials, improve efficiency, and protect the ecological environment. Attached Figure Description

[0020] Figure 1 This is a flowchart of the online stress monitoring multi-point synchronous pipeline lifting method in this invention;

[0021] Figure 2 This is a schematic diagram of the installation of the temporary limiting bracket in this invention;

[0022] Figure 3 This is a schematic diagram of the support points of the pipe lifting bracket in this invention;

[0023] Figure 4 This is a schematic diagram of the saddle support in this invention.

[0024] In the diagram: 1. Temporary limiting bracket; 2. Support point; 3. Saddle support. Detailed Implementation

[0025] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] In the description of this invention, it should be noted that terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, terms such as "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0028] Figure 1 This is a flowchart of the online stress monitoring multi-point synchronous pipeline lifting method in this invention; Figure 2 This is a schematic diagram of the installation of the temporary limiting bracket in this invention; Figure 3 This is a schematic diagram of the support points of the pipe lifting bracket in this invention; Figure 4 This is a schematic diagram of the saddle-type support in this invention. Please refer to [link / reference]. Figures 1 to 4 As shown, a preferred embodiment is illustrated, illustrating an online stress monitoring method for multi-point synchronous pipeline lifting, comprising:

[0029] S1. Pipeline displacement calculation: Analyze and calculate the settlement displacement of the liquid inlet pipeline based on the design drawings and on-site measurements.

[0030] S2. Install temporary limiting bracket 1. Install temporary limiting bracket 1 on the steel structure frame layer in front of the tank. By setting temporary limiting bracket 1, it can be ensured that the pipe will not be displaced or its elevation will sink during the removal of the support and the lifting of the pipe.

[0031] S3. Install the pipe lifting bracket. Install a steel structure load-bearing frame in the steel structure frame layer in front of the tank as the support point for the pipe support and hanger. In this embodiment, the pipe lifting bracket facilitates the fixing of the pipe, restricts the position and angle of the pipe, and facilitates the lifting of the pipe.

[0032] After the pipeline lifting bracket is installed, scaffolding needs to be erected on the tank wall (outer wall of the natural gas storage tank). Then, the pipeline insulation support is removed and the buttress support is installed. During the buttress support installation, the buttress support is welded to the tank wall, and then non-destructive testing of the weld joint is performed. After the testing is completed, step S4 is performed.

[0033] S4. Set up pipeline lifting measures, repair the buttress support steel structure of the pipeline in the first layer, the pipeline in the second layer and the pipeline in the third layer in sequence, and lift them with a chain hoist; In this embodiment, the pipeline has three layers, which are divided into the first layer, the second layer and the third layer from bottom to top. Repair the buttress support steel structure of the pipeline in each layer from bottom to top, and then lift them with a chain hoist.

[0034] S5. Install pipeline lifting monitoring facilities, calculate stress concentration locations through modeling, and set monitoring points at locations with large strain; for data acquisition, the HBM SoMat eDaq dynamic data acquisition system can be used, and strain gauges can be attached to the pipeline wall. The strain gauges are resistance strain gauges; stress monitoring principle: strain-electrical properties; when the resistance strain gauge senses the strain of the component, its resistance changes simultaneously, and the stress change at the monitored location is calculated based on the resistance change.

[0035] The pipeline lifting monitoring facilities include displacement and flange opening monitoring, online pipeline stress monitoring, and crack condition monitoring during the lifting process.

[0036] S6. Confirmation of pipeline lifting. In this embodiment, the pipeline is a buttress pipeline.

[0037] Furthermore, as a preferred implementation, in S2, the temporary limiting bracket 1 is installed below the pipe insulation support and must not be in direct contact with the pipe.

[0038] Furthermore, as a preferred implementation, in S3, the installation of the steel structure load-bearing frame needs to be carried out according to the requirements of the steel structure construction plan, and a saddle-type support 3 needs to be installed between the pipe and the steel structure load-bearing frame. In this embodiment, the specific structure of the saddle-type support 3 can be found in [reference needed]. Figure 4 As shown, the upper section of the saddle-type support 3 is semi-circular, which facilitates the support of the pipeline. During the lifting process, it can prevent the pipeline from rolling on the steel structure load-bearing frame, thus improving the stability of the lifting.

[0039] Furthermore, as a preferred implementation, in S4, for each layer of pipe repaired, lifting chains are installed on both sides of the pipe to share part of the pipe load. The upper part of the chain hoist is suspended from the steel structure of the corresponding layer's buttress support, and the lower part of the chain hoist is secured to the pipe with slings. In this embodiment, pipe lining is used to pad the edges where the slings contact the steel structure to prevent the edges from cutting the slings.

[0040] Furthermore, as a preferred implementation method, in S5, during the pipeline lifting process, displacement measurement points are set from the top valve position of the tank to the shut-off valve of the second-level platform in front of the tank in the unloading manifold, and a flange opening measurement point is set at each of the upper and lower liquid inlet pipe interface flanges, so as to monitor the pipeline displacement changes during the pipeline lifting process and ensure that the entire pipeline lifting process is carried out within a safe and controllable range.

[0041] Furthermore, as a preferred implementation method, during the pipeline lifting process, multiple displacement measurement points are set at the unloading manifold from the top valve position of the tank to the shut-off valve of the second-level platform in front of the tank. A flange opening measurement point is set at both the upper and lower inlet pipe interface flanges to monitor pipeline displacement changes during the pipeline lifting process, ensuring that the entire pipeline lifting process is carried out within a safe and controllable range until the lifting is completed. At the same time, the crack status is monitored throughout the process using non-destructive testing.

[0042] Furthermore, as a preferred implementation method, in S6, the unloading manifold is lifted by using hydraulic jacks for lifting and chain hoisting assistance.

[0043] The online stress monitoring multi-point synchronous pipeline lifting method provided in this invention can solve the problem of overall system displacement with the same tension at multiple points under the premise of controllable strain, ensuring the safety of the construction process, better guaranteeing the quality of pipeline repair, improving efficiency, saving consumables, and reducing material costs.

[0044] The online stress monitoring and multi-point synchronous pipeline lifting method provided in this invention has been applied in the Beihai LNG (liquefied natural gas) storage tank repair project. Specific application examples are as follows:

[0045] The TK-02 tank repair project at the Beihai LNG receiving terminal is the world's first LNG cryogenic tank repair project with media present. The construction environment is extremely special. One-third of the liquefied natural gas is still inside the tank, and the overall working environment of the tank is in a severely burned state. Some pipelines are also leaking. Although the pipeline system is filled with nitrogen for isolation, the overall construction environment is still not optimistic.

[0046] Finite element analysis was used to analyze and calculate the settlement stress and strain of the DN1000 inlet pipeline. The results showed that under the action of its own weight and internal pressure load, when the DN1000 inlet pipeline settled by 109 mm, the maximum stress was 310.420 MPa, located at the elbow above the tee, which is less than the material's yield strength of 355 MPa. As the settlement displacement decreased, the stress value at the location of the maximum stress gradually decreased. To ensure the safety of the weld, the DN1000 inlet pipe was raised by 109 mm to its original position. Temporary limiting bracket 1 was installed between columns T22-T23 of row A03 / 4 at the 22.2-meter level of the steel structure frame layer in front of the tank. A steel structure load-bearing frame was installed at the 22.2-meter level of the steel structure frame layer in front of the tank as the support point for the pipe supports. The installation of the steel structure load-bearing frame was carried out in accordance with the requirements of the steel structure construction plan. Saddle supports 3 were installed between the pipes and the steel structure load-bearing frame. The saddle supports 3 were manufactured in accordance with the "Container Supports" (NB / T47065.1-2018) - Lightweight (Type A) Saddle Supports 3. The buttress support steel structures of the pipes on the first, second, and third layers were repaired in sequence and lifted with chain hoists. For each layer of pipes repaired, a chain hoisting distribution section was set on both sides of the pipe. The pipeline load is distributed, with the upper part of the chain hoist suspended from the steel structure of the buttress support on this layer, and the lower part of the chain hoist secured to the pipeline with slings. Pipe sheaths are placed at the contact points between the slings and the steel structure to prevent the slings from being cut. Displacement and flange opening monitoring are conducted. During the pipeline lifting process, seven displacement measurement points are set from the unloading manifold from the top valve of the tank to the shut-off valve on the second-level platform in front of the tank, and one flange opening measurement point is set at each of the upper and lower inlet pipe flange interfaces. This is to facilitate monitoring of pipeline displacement changes during the pipeline lifting process and ensure that the entire pipeline lifting process is carried out within a safe and controllable range. Measurements are taken after the first 5mm lift, and then every 10mm afterward, with measurement records filled out until the lifting is completed. Afterward, online stress detection is carried out. During the pipeline lifting process, the strain of key parts of the lifting pipeline, such as elbows, tees, and the outer wall pipeline at the internal crack after the top valve, is measured in real time. It is estimated that 78 measurement points will be measured. Among them, there are 54 measurement points at elbows, 16 measurement points at tees, and 8 measurement points on the outer wall pipeline at the internal crack after the top valve. After confirming that the steel structure repair of the buttress supports for the pipes on the first, second, and third floors has been completed, the materials (pipe insulation supports) have been removed, the auxiliary facilities for pipe lifting have been completed, and the non-destructive testing of the relevant welds has passed, the pipes will be lifted and reset.

[0047] The above description is merely a preferred embodiment of the present invention and does not limit the implementation and protection scope of the present invention. Those skilled in the art should realize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for online stress monitoring and multi-point synchronous pipeline lifting, characterized in that, include: S1. Pipeline displacement calculation: Analyze and calculate the settlement displacement of the liquid inlet pipeline based on the design drawings and on-site measurements. S2. Install temporary limit brackets. Install temporary limit brackets on the steel structure frame layer in front of the tank. S3. Install pipe lifting brackets and install a steel structure load-bearing frame in the steel structure frame layer in front of the tank as the support point for pipe supports and hangers. S4. Set up pipeline lifting measures, repair the buttress support steel structure of the pipelines on the first floor, the second floor and the third floor in sequence, and lift them with chain hoists; S5. Install pipeline lifting monitoring facilities, calculate the stress concentration location through modeling, and set monitoring points at locations with large strain; S6. Confirmation of pipeline lifting; In S2, the temporary limit bracket is installed below the pipe insulation support and must not be in direct contact with the pipe. In S3, the installation of the steel structure load-bearing frame must be carried out in accordance with the requirements of the steel structure construction plan, and saddle supports need to be installed between the pipes and the steel structure load-bearing frame. In S5, during the pipeline lifting process, displacement measurement points are set from the top valve position of the tank to the shut-off valve of the second-level platform in front of the tank in the unloading manifold, and a flange opening measurement point is set at the upper and lower liquid inlet pipe interface flanges.

2. The online stress monitoring multi-point synchronous pipeline lifting method as described in claim 1, characterized in that, In S4, for each layer of pipe repaired, hanging chains are installed on both sides of the pipe to share part of the pipe load. The upper part of the chain hoist is suspended on the steel structure of the buttress support of the corresponding layer, and the lower part of the chain hoist is tied and fixed to the pipe with slings.

3. The online stress monitoring multi-point synchronous pipeline lifting method as described in claim 1, characterized in that, During the pipeline lifting process, multiple displacement measurement points are set up from the top valve of the tank to the shut-off valve of the second-level platform in front of the tank in the unloading manifold. A flange opening measurement point is set up at the upper liquid inlet pipe interface flange and the lower liquid inlet pipe interface flange.

4. The online stress monitoring multi-point synchronous pipeline lifting method as described in claim 1, characterized in that, In S6, the unloading manifold is lifted by using hydraulic jacks and chain hoists.

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