CN209923437U

CN209923437U - Auxiliary anode for storage tank cathode protection

Info

Publication number: CN209923437U
Application number: CN201920395881.XU
Authority: CN
Inventors: 窦宏强; 徐水营; 陈喆
Original assignee: China National Petroleum Corp; China Petroleum Pipeline Engineering Corp
Current assignee: China National Petroleum Corp; China Petroleum Pipeline Engineering Corp
Priority date: 2019-03-27
Filing date: 2019-03-27
Publication date: 2020-01-10
Anticipated expiration: 2029-03-27

Abstract

The utility model relates to a storage tank cathodic protection is with supplementary positive pole, include: the storage tank comprises auxiliary anode bodies 1 arranged parallel to a storage tank bottom plate and conductive concrete 2 poured around the auxiliary anode bodies 1, wherein the auxiliary anode bodies 1 are fixed at the central positions of the conductive concrete 2, a plurality of auxiliary anode bodies 1 are arranged, the auxiliary anode bodies 1 are mutually crossed to form a net-shaped or annular structure, and the crossed points are electrically continuous. The utility model has the advantages that: the auxiliary anode of the utility model has enough strength and intact structure in the whole design period, thereby ensuring that the whole storage tank foundation cushion layer has enough bearing capacity and solving the problem of instability of the storage tank foundation cushion layer; and the intact structure also ensures the basic constancy of the auxiliary anode grounding resistance, so that the output current of the potentiostat meets the requirement of cathodic protection, and the long-term effectiveness of a cathodic protection system is ensured.

Description

Auxiliary anode for storage tank cathode protection

Technical Field

The utility model relates to an oil gas storage tank technical field, concretely relates to storage tank cathodic protection is with supplementary positive pole.

Background

The cathodic protection system on the outer surface of the bottom plate of the overground vertical storage tank consists of a constant potential rectifier, an auxiliary anode ground bed, a reference electrode, a power-on point, a connecting cable and the like. In order to ensure the effectiveness of a cathode protection system, an auxiliary anode for cathode protection of a bottom plate of a storage tank is usually in a near-anode mode, and the anode is laid between the bottom plate of the tank and an impermeable membrane in a cushion layer and is in a fine sand layer with the height of about 0.5 m from the bottom plate of the storage tank; the anode usually adopts MMO anode with strip, MMO anode with line or conductive polymer anode with line, in order to ensure the uniform distribution of cathodic protection current, the MMO anode with strip, MMO anode with line or conductive polymer anode with line form a horizontal net structure or a ring structure, and the MMO anode with strip, MMO anode with line or conductive polymer anode with line is installed in parallel with the bottom plate of the storage tank; in order to ensure that the grounding resistance and the output current of the auxiliary anode are matched with the power of the potentiostat, a certain amount of small-particle coke filler is filled around the MMO strip anode, the MMO wire anode or the conductive polymer wire anode to reduce the grounding resistance of the anode and increase the output of current; the particle size range of the filling coke is as follows: the 20-mesh sieve is less than or equal to 2 percent, and the 100-mesh sieve is more than or equal to 80 percent.

The auxiliary anode is installed in two ways: 1) constructing the storage tank bottom plate and a cushion layer of the storage tank bottom plate simultaneously, tamping and filling the storage tank bottom plate and the cushion layer sequentially from bottom to top in a layering manner, and installing an MMO belt anode, an MMO wire anode or a conductive polymer wire anode in a fine sand layer; 2) firstly, according to the structure of the cushion layer, sequentially tamping and filling the cushion layer by layer from bottom to top in the range of the whole tank bottom, forming a reticular or annular groove on the tamped cushion layer, installing an MMO belt anode, an MMO wire anode or a conductive polymer wire anode in the groove, and finally backfilling and tamping the excavated groove with the embedded anode.

Because the cushion layer below the storage tank bottom plate needs to bear a huge load when the whole storage tank is full of tank capacity, the cushion layer below the storage tank bottom plate needs to have high enough strength, the cushion layer is usually made of gravel, fine sand, plain concrete, asphalt sand and the like, and the strength of the cushion layer meets the requirement by means of layering, tamping, vibrating, compacting and the like. And the MMO anode with the anode, the MMO anode with the anode or the conductive polymer anode with the anode is filled with fine particle coke filler with proper thickness and size, and no matter which installation mode is adopted by the MMO anode with the coke, the MMO anode with the anode or the conductive polymer anode with the conductive polymer, the coke is composed of very loose particles with very low strength, so that the strength of the cushion layer on which the MMO anode with the anode, the MMO anode with the MMO or the conductive polymer anode with the conductive polymer is installed is reduced, the bearing capacity is reduced, the whole storage tank foundation is unstable, and the safe operation of the storage tank is further influenced. And then the coke filled in the anode body of the MMO belt, the anode of the MMO line or the anode body of the conductive polymer line and the periphery is damaged and damaged by adopting construction means such as dynamic compaction or vibration. During vibration construction, the contact of the vibrating rod and the auxiliary anode can break the anode, or the metal oxide layer and the conductive polymer layer on the surface of the anode disappear, are damaged or are thinned, so that the service life of the anode is influenced, and the uniform distribution of the anode current is also influenced. During the dynamic compaction construction, the dynamic compaction can change the form of coke aggregation filled around the MMO strip anode, the MMO wire anode or the conductive polymer wire anode, so that the effective section of the anode output is reduced, the grounding resistance of the anode is increased, and the service life of the anode is shortened. These deficiencies can lead to poor cathodic protection and even failure of the cathodic protection system.

SUMMERY OF THE UTILITY MODEL

To the weak point that exists in the above-mentioned problem, the utility model provides a storage tank cathodic protection is with supplementary positive pole has solved the unstable problem of storage tank basis bed course, has guaranteed supplementary positive pole ground resistance's basic invariant, and the long-term effective of cathodic protection system.

In order to achieve the above object, the present invention provides an auxiliary anode for protecting cathode of a storage tank, comprising: the storage tank comprises auxiliary anode bodies and conductive concrete, wherein the auxiliary anode bodies are arranged in parallel to a storage tank bottom plate, the conductive concrete is poured around the auxiliary anode bodies, the auxiliary anode bodies are fixed at the central positions of the conductive concrete, the auxiliary anode bodies are arranged in a plurality, the auxiliary anode bodies are mutually crossed to form a net-shaped or annular structure, and the crossed points are electrically continuous.

As a further improvement of the utility model, the auxiliary anode body is an MMO belt anode, an MMO line anode or a conductive polymer line anode.

As a further improvement of the utility model, the natural bulk density of the conductive concrete is more than or equal to 1400kg/m³Resistivity of<10 omega cm, the compressive strength is 21MPa after 28 days of casting, the shrinkage rate is less than or equal to 0.1 percent after 28 days of casting, and the PH value is neutral.

As the utility model discloses further improve, the continuous welding of crosspoint electricity, and the anticorrosive sealing of solder joint.

The utility model has the advantages that:

the auxiliary anode of the utility model has enough strength and intact structure in the whole design period, thereby ensuring that the whole storage tank foundation cushion layer has enough bearing capacity and solving the problem of instability of the storage tank foundation cushion layer; and the intact structure also ensures the basic constancy of the auxiliary anode grounding resistance, so that the output current of the potentiostat meets the requirement of cathodic protection, and the long-term effectiveness of a cathodic protection system is ensured.

Drawings

FIG. 1 is a schematic structural view of an auxiliary anode for the cathodic protection of a storage tank according to the present invention;

FIG. 2 is a cross-sectional view of FIG. 1;

FIG. 3 is a schematic diagram of a mesh-laid storage tank cathodic protection system;

fig. 4 is a schematic diagram of a looped-laid tank cathodic protection system.

In the figure:

1. an auxiliary anode body; 2. electrically conductive concrete; 3. a copper-core cable; 4. a reference electrode; 5. a potentiostat; 6. a storage tank foundation mat layer.

Detailed Description

As shown in fig. 1-2, an auxiliary anode for protecting a cathode of a storage tank according to an embodiment of the present invention includes: the storage tank comprises auxiliary anode bodies 1 arranged parallel to a storage tank bottom plate and conductive concrete 2 poured around the auxiliary anode bodies 1, wherein the auxiliary anode bodies 1 are fixed at the central positions of the conductive concrete 2, a plurality of auxiliary anode bodies 1 are arranged, the auxiliary anode bodies 1 are mutually crossed to form a net-shaped or annular structure, and the crossed points are electrically continuous.

Wherein, the auxiliary anode body 1 is selected from an MMO strip anode, an MMO line anode or a conductive polymer line anode.

The natural bulk density of the conductive concrete 2 is more than or equal to 1400kg/m³Resistivity of<10 omega cm, the compressive strength is 21MPa after 28 days of casting, the shrinkage rate is less than or equal to 0.1 percent after 28 days of casting, and the PH value is neutral.

As shown in fig. 3-4, during installation, firstly, the foundation cushion layer 6 of the storage tank is backfilled to the height of the embedded auxiliary anode body 1 and is tamped; installing a casting mold of the conductive concrete 2 on the tamped foundation bed course 6 of the storage tank, wherein the size, the dimension, the shape, the structure and the like of the mold are designed according to requirements; the plurality of auxiliary anode bodies 1 should form a net-like or ring-like structure and cross each other. At the same time, the thickness of the conductive concrete 2 filled around the auxiliary anode body 1 is ensured to meet the requirements.

Arranging and installing the auxiliary anode body 1 along a laid pouring mold, performing electric continuous welding on the auxiliary anode body 1 at a cross point, performing anticorrosion sealing protection on a welding spot, and fixing the auxiliary anode body 1 at the central position of the pouring mold; stirring the conductive concrete 2 and water to form slurry with certain viscosity, and pouring the slurry into a pouring mold section by section to pour; after the pouring is finished, the concrete is kept for a certain time for curing, and after the concrete is cured and the strength of the concrete meets the requirement, the pouring mold can be removed for the next work.

After the auxiliary anode body 1 is laid, the auxiliary anode body and the reference electrode 4 are respectively connected with a constant potential rectifier 5 through a copper core cable 3 to form a storage tank cathode protection system.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An auxiliary anode for cathodic protection of a storage tank, comprising: the auxiliary anode body (1) is arranged in parallel to the storage tank bottom plate, the conductive concrete (2) is poured around the auxiliary anode body (1), the auxiliary anode body (1) is fixed at the central position of the conductive concrete (2), the auxiliary anode bodies (1) are arranged in a plurality of numbers, the auxiliary anode bodies (1) are mutually crossed to form a net-shaped or annular structure, and the crossed points are electrically continuous.

2. Auxiliary anode for cathodic protection of storage tanks according to claim 1, characterized in that the auxiliary anode body (1) is selected from MMO tape anode, MMO wire anode or conductive polymer wire anode.

3. The auxiliary anode for cathodic protection of storage tanks according to claim 1, characterized in that the natural bulk density of the conductive concrete (2) is not less than 1400kg/m³Resistivity of<10 omega cm, the compressive strength is 21MPa after 28 days of casting, the shrinkage rate is less than or equal to 0.1 percent after 28 days of casting, and the PH value is neutral.

4. The auxiliary anode for cathodic protection of a storage tank as in claim 1 wherein the crossover point is electrically continuous welded and the weld is corrosion resistant sealed.