Cathode protection device for buried steel pipeline of gas plant station

Abstract

The utility model discloses a cathode protection device for a buried steel pipeline in a gas plant station, which comprises a test pile and a rod-shaped anode, the test pile is provided with a junction box wiring panel, the junction box wiring panel is provided with a plurality of wiring terminals, one end of a first wiring terminal and one end of a second wiring terminal are connected with the steel pipeline, and the other end of the first wiring terminal and the other end of the second wiring terminal are connected with the rod-shaped anode. The rod-shaped anode is connected to the third wiring terminal through a first cable; and the third wiring terminal, the first wiring terminal, the second wiring terminal and the fourth wiring terminal are sequentially connected through copper connecting sheets. According to the utility model, the problems that the impressed current scheme interferes with the surrounding metal stray current, the ground bed site selection distance and economy are poor, and the sacrificial anode scheme has short service life are solved.

Description

Technical Field

[0001] The utility model belongs to the technical field of cathodic protection, and in particular relates to a cathodic protection device for buried steel pipelines of gas plants. Background Art

[0002] For the regional cathodic protection of urban gas plants, the buried pipelines, equipment, reinforced concrete foundations and grounding systems in the entire area are electrically connected and integrated, with different distribution density and laying environments, which leads to large and uneven distribution of cathodic protection current required for plants. The traditional sacrificial anode protection method has problems such as small anode output current, short protection distance, difficult to adjust the protection current output and difficulty in anode replacement. Therefore, the traditional sacrificial anode protection method is not the best solution for the regional cathodic protection target of plants. The forced current protection system has a large output current and a wide protection range, but the cost is high. It is generally used for larger plants such as upstream long-distance pipelines. The urban gas plants are small in size and have fewer buried steel pipelines. About 60% to 80% of the electric energy output by the forced current system anode is consumed in the lightning protection grounding network, so it is less economical to use it in urban gas plants. Therefore, it is particularly important to choose a suitable cathodic protection scheme.

[0003] In the existing related technologies, there are usually two cathodic protection methods for urban gas plants. Method 1: Insulate the pipelines inside and outside the station, and use impressed current cathodic protection for the buried steel pipelines in the plant. Figure 1 As shown, the system consists of a constant potential instrument 1', an anode bed 2', a reference electrode 3 and a cable 5. First, when the impressed current protection scheme is adopted in the gas station, the distance between the station and the surrounding buried metal facilities must be considered. If the distance is too close, the metal will be corroded by stray current. Secondly, whether the anode bed uses a deep well anode or a shallow buried anode, the land use issue is involved. The urban gas stations are small and the space inside the station is limited. On the one hand, if the proposed anode bed is located inside the station, the distance between the bed and the pipeline outside the station cannot be guaranteed, which will have an adverse effect on the implementation effect of the cathodic protection of the buried pipeline outside the station. On the other hand, whether the geological conditions of the proposed bed location are suitable for well drilling or shallow burial will also have a great impact on the implementation effect of the scheme. Finally, this scheme is mostly used for large gas stations with upstream long-distance pipelines, while there are fewer buried pipelines in urban gas stations. At this time, the use of impressed current cathodic protection is considered, resulting in extremely high investment in cathodic protection per unit length of pipeline, which does not have good economic efficiency.

[0004] Method 2: Insulate the pipelines inside and outside the station, and use sacrificial anode protection method for buried steel pipelines in the plant station. Figure 2As shown in the figure, the system consists of a test pile 1, a reference electrode 3, a cable 5 and a sacrificial anode 2. First of all, this scheme is affected by the number of buried steel pipelines and the anti-corrosion layer in the plant. As the service life of the buried pipelines in the station increases and the number of leaks in the anti-corrosion layer increases, the sacrificial anode cathodic protection radius will decrease and the consumption will be faster, which will affect the cathodic protection effect of the buried steel pipelines in the plant. Secondly, all pipelines in the urban gas plant are connected to the grounding network in the station, resulting in most of the sacrificial anodes being consumed on the buried grounding network. The service life of the sacrificial anode is short, causing the cathodic protection in the plant to fail to meet the standards in a short period of time. Although this scheme can protect the pipeline, the scheme itself lacks improvement measures to extend the service life of the sacrificial anode. Finally, due to the short service life of the sacrificial anode, the anode needs to be replaced frequently, which causes great damage to the plant ground and is nothing more than a labor-intensive and costly measure.

[0005] Therefore, how to conveniently, effectively, comprehensively and economically solve the cathodic protection of buried steel pipelines in urban gas plants is a technical problem that urgently needs to be solved in this field. Summary of the invention

[0006] In view of the deficiencies of the prior art, the utility model provides a cathodic protection device for buried steel pipelines in gas plants.

[0007] The solution adopted by the utility model to solve its technical problems is as follows:

[0008] A cathodic protection device for buried steel pipelines in gas plants comprises a test pile and a rod-shaped anode. The test pile is provided with a junction box and a junction panel. The junction box and the junction panel are provided with a plurality of junction terminals, wherein one end of a first junction terminal and a second junction terminal are both connected to the steel pipeline, and the rod-shaped anode is connected to a third junction terminal through a first cable; and the third junction terminal, the first junction terminal, the second junction terminal and the fourth junction terminal are sequentially connected through copper connecting pieces.

[0009] Preferably, the rod-shaped anodes are laid along the steel pipeline and evenly distributed on one side of the steel pipeline. Every four rod-shaped anodes form a group, and the four rod-shaped anodes are connected by a second cable.

[0010] Preferably, one rod-shaped anode is arranged at intervals of 5 to 10 meters.

[0011] Preferably, a reference electrode is provided, and the reference electrode is connected to a fifth terminal on the wiring panel of the junction box via a third cable.

[0012] Preferably, a cathodic protection inspection piece is provided, which is placed on the side of the steel pipeline away from the anode and is connected to a fourth terminal on the wiring panel of the junction box through a fourth cable.

[0013] Preferably, it also includes a grounding grid inside the gas plant, which is provided with a zinc-clad steel grounding wire and a zinc-clad steel grounding electrode, and the zinc-clad steel grounding wire and multiple zinc-clad steel grounding electrodes are connected by exothermic welding; the zinc-clad steel grounding wire and the metal base of the above-ground equipment are connected by galvanized flat iron, and the galvanized flat iron is welded to the metal base of the equipment.

[0014] Preferably, the welding points between the zinc-clad steel grounding wire and the plurality of zinc-clad steel grounding electrodes are protected from corrosion by a viscoelastic material coated with a polypropylene tape.

[0015] The utility model adopts the combined protection of sacrificial anode and zinc-clad steel grounding grid in the town gas plant station. The sacrificial anode adopts rod-shaped anode, and the lightning protection grounding grid in the station adopts zinc-clad steel. The sacrificial anode is connected to the buried steel pipeline through the junction box and cable. A sacrificial anode is set every 5 to 10 meters. The cathode protection inspection piece and the reference electrode are placed on both sides of the pipeline respectively. The inspection piece and the reference electrode are connected to the junction box through the cable. The lightning protection grounding grid in the station selects zinc-clad steel grounding wires and grounding electrodes of corresponding diameters according to the soil resistivity, and arranges them in a mesh around the skid-mounted equipment. When connecting the grounding wire and the grounding electrode, aluminum thermite welding is required, and the welding points are anti-corrosive with viscoelastic body + polypropylene tape.

[0016] The utility model overcomes the problems of interference of impressed current scheme with surrounding metal stray current, ground bed site spacing, poor economy and short service life of sacrificial anode scheme. The utility model does not need to frequently replace sacrificial anodes to ensure the pipeline cathodic protection effect. By adopting zinc-clad steel lightning protection grounding grid, the number of sacrificial anodes is reduced. In addition, after the service life of sacrificial anodes is extended, there is no need to frequently replace anodes, thereby reducing damage to the plant ground and significantly improving the effect and reliability of pipeline cathodic protection. Furthermore, the utility model combines the advantages of two traditional cathodic protection methods, which not only improves the pipeline cathodic protection effect but also solves the problem of poor economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present application. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention.

[0018] Figure 1 It is a schematic diagram of the impressed current protection method for buried steel pipelines in urban gas plants in the prior art;

[0019] Figure 2 It is a schematic diagram of the sacrificial anode protection method for buried steel pipelines of urban gas plants in the prior art;

[0020] Figure 3 This is a schematic diagram of the installation of a distributed sacrificial anode protection device for buried steel pipelines in a town gas plant in a preferred embodiment of the utility model;

[0021] Figure 4 This is a schematic diagram of the structure of the wiring panel of the junction box in the preferred embodiment of the utility model.

[0022] Figure 5 This is a schematic diagram of the installation of a distributed sacrificial anode in a preferred embodiment of the utility model;

[0023] Figure 6 This is a schematic diagram of the connection of the zinc-clad steel wiring mesh in the preferred embodiment of the utility model.

[0024] Among them: 1'—potentiostat; 2'—anode bed; 1—test pile; 1"—test pile or junction box; 2—rod anode; 3—reference electrode; 4—cathodic protection inspection piece; 5—cable; 6—junction box wiring panel; 6-1~6-8—wiring terminals; 6-9—copper connecting piece; 7—galvanized flat iron; 8—zinc-clad steel grounding wire; 9—zinc-clad steel grounding electrode. DETAILED DESCRIPTION

[0025] The present invention is further explained below in conjunction with specific implementation methods.

[0026] like Figure 3-6 As shown, this embodiment relates to a cathodic protection device for buried steel pipelines in urban gas plants, including a test pile 1", a rod-shaped anode 2, a reference electrode 3, a cathodic protection inspection sheet 4 and a cable 5, a junction box wiring panel 6, a galvanized flat iron 7, a zinc-clad steel grounding wire 8 and a zinc-clad steel grounding electrode 9. In this embodiment, the buried steel pipelines in urban gas plants are protected by sacrificial anodes and zinc-clad steel grounding grids. The sacrificial anodes are installed as shown in the figure. Figure 3 As shown. The test pile 1" is provided with a junction box wiring panel 6, and the junction box wiring panel 6 is provided with 8 terminals, namely, terminals 6-1, 6-2, 6-3, 6-4, 6-5, 6-6, 6-7, and 6-8. The rod-shaped anode 2 is connected to the junction box terminal 6-3 through a cable 5. One end of the terminal 6-1 and the terminal 6-2 are both connected to the buried steel pipeline A in the plant station, and the pipeline A in the station is connected to the pipeline B outside the station by an insulating device C. The terminals 6-3, 6-1, and 6-2 are connected in sequence through copper connecting pieces 6-9. In order to make the cathodic protection current distribution more uniform, this embodiment sets a rod-shaped anode 2 at intervals of 5 to 10 meters, and the reference electrode 3 is connected to the terminal 6-5 of the junction box through a cable 5. At the same time, it is convenient to measure the cathodic protection polarization potential. This embodiment adds a cathodic protection inspection piece 4, which is placed on the buried pipeline away from the anode side and connected to the terminal 6-4 of the junction box through a cable 5. The terminal 6-4 and the terminal 6-2 are connected by a copper connecting piece. The junction box wiring panel is as follows Figure 4 shown.

[0027] The rod-shaped anode 2 is distributed near the pipeline and connected to the junction box through the cable 5. The installation structure is as follows: Figure 5 As shown, the cable 5 is buried in the medium sand D, and the medium sand D is covered with machine bricks E and backfill soil F in sequence. The grounding grid in the town gas plant station is composed of a zinc-clad steel grounding wire 8 and a zinc-clad steel grounding electrode 9. The grounding wire 8 is connected to the metal base G of the above-ground equipment by a galvanized flat iron 7. In this embodiment, the two galvanized flat irons 7 are connected by bolts H, and the galvanized flat iron 7 is welded to the metal base G of the equipment. The specific installation structure is as follows: Figure 6 I is the dividing point between the galvanized flat iron 7 and the zinc-clad steel grounding wire 8.

[0028] In this embodiment, the rod-shaped anodes 2 for pipeline cathodic protection are laid along the pipeline and evenly distributed on one side of the pipeline, and every four anodes are connected in series through a cable 5. In order to facilitate the measurement of the cathodic protection polarization potential, the present embodiment adds a cathodic protection inspection sheet 4. When measuring the polarization potential, the copper connecting sheet 6-10 needs to be disconnected from the terminal 6-2. The cathodic protection polarization potential is measured at the moment of disconnection to determine whether the cathodic protection effect meets the standard.

[0029] The grounding grid in the plant station adopts a zinc-clad steel grounding grid, which is composed of a zinc-clad steel grounding wire 8 and a zinc-clad steel grounding electrode 9. The grounding wire 8 and multiple grounding electrodes 9 are vertically connected by exothermic welding, and the welding points are covered with a viscoelastic material and polypropylene tape for corrosion protection; in addition, when drilling holes for the grounding electrode, it is required to drill holes first and then slowly put the grounding electrode into the hole. In order to protect the zinc layer on the surface of the grounding grid, the grounding grid needs to be filled with fine sand above and below. The utility model adopts zinc-clad steel, which improves the protection effect and service life of the sacrificial anode.

[0030] The above describes the technical solution of the utility model in combination with the preferred embodiments shown in the accompanying drawings, but it is easy for those skilled in the art to understand that the protection scope of the utility model is obviously not limited to these specific embodiments. Without departing from the principle of the utility model, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the utility model.

Claims

1. Cathodic protection device for buried steel pipelines in gas plants, characterized by The invention comprises a test pile (1'') and a rod-shaped anode (2). The test pile (1'') is provided with a junction box and a junction panel (6). The junction box and the junction panel (6) are provided with a plurality of junction terminals, wherein one end of a first junction terminal (6-1) and a second junction terminal (6-2) are both connected to a steel pipe (A). The rod-shaped anode (2) is connected to a third junction terminal (6-3) via a first cable. The third junction terminal (6-3), the first junction terminal (6-1), the second junction terminal (6-2) and the fourth junction terminal (6-4) are connected in sequence via a copper connecting piece (6-9). The rod-shaped anodes (2) are laid along the steel pipeline and evenly distributed on one side of the steel pipeline. Four rod-shaped anodes (2) form a group, and the four rod-shaped anodes (2) are connected by a second cable. The invention also comprises a grounding network in a gas plant, wherein the grounding network in the gas plant is provided with a zinc-clad steel grounding wire (8) and a zinc-clad steel grounding electrode (9), wherein the zinc-clad steel grounding wire (8) and a plurality of zinc-clad steel grounding electrodes (9) are connected by exothermic welding; the zinc-clad steel grounding wire (8) is connected to a metal base (G) of an above-ground device by a galvanized flat iron (7), and the galvanized flat iron (7) is welded to the metal base (G) of the device.

2. The cathodic protection device for buried steel pipelines in gas plants as claimed in claim 1, characterized in that: A rod-shaped anode (2) is arranged at intervals of 5 to 10 meters.

3. The cathodic protection device for buried steel pipelines of gas plants as claimed in any one of claims 1 to 2, characterized in that: A reference electrode (3) is provided, and the reference electrode (3) is connected to a fifth wiring terminal (6-5) on a wiring panel (6) of a wiring box via a third cable.

4. The cathodic protection device for buried steel pipelines in gas plants as claimed in claim 3, characterized in that: A cathode protection inspection piece (4) is provided, and the cathode protection inspection piece (4) is placed on the side of the steel pipeline away from the anode, and is connected to a fourth terminal (6-4) on a wiring panel (6) of a junction box via a fourth cable.

5. The cathodic protection device for buried steel pipelines in gas plants as claimed in claim 1, characterized in that: The welding point between the zinc-clad steel grounding wire (8) and the zinc-clad steel grounding electrode (9) is coated with a polypropylene tape with a viscoelastic material for corrosion protection.

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