CN210176957U - Anti-corrosion device for outer surface of bottom plate of underground vertical storage tank - Google Patents
Anti-corrosion device for outer surface of bottom plate of underground vertical storage tank Download PDFInfo
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- CN210176957U CN210176957U CN201920710350.5U CN201920710350U CN210176957U CN 210176957 U CN210176957 U CN 210176957U CN 201920710350 U CN201920710350 U CN 201920710350U CN 210176957 U CN210176957 U CN 210176957U
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Abstract
The utility model relates to an anti-corrosion device of ground vertical storage tank bottom plate surface, a serial communication port, include: the anticorrosive layer is coated on the outer surface of the bottom plate of the storage tank and is positioned in the area of each tank plate except the 5cm width range of the edge welding heat affected zone; the cathodic protection system is arranged in a cushion layer below the bottom plate of the storage tank and adopts a forced current cathodic protection system or a sacrificial anode protection system; the corrosion inhibitor protection system comprises a plurality of PVC porous pipes which are arranged in parallel with a storage tank bottom plate and powdery gaseous corrosion inhibitors filled in the PVC porous pipes, wherein the end parts of two ends of each PVC porous pipe are sealed by sealing caps, and the PVC porous pipes are arranged in a cushion layer below the storage tank bottom plate or between the storage tank bottom plate and an impermeable membrane at the bottom of the storage tank. The utility model discloses an anticorrosion device realizes the comprehensive effectual anticorrosion protection of storage tank bottom plate through anticorrosive coating, cathodic protection system and corrosion inhibitor protection system.
Description
Technical Field
The utility model relates to a vertical storage tank anticorrosion technical field, concretely relates to anticorrosion device of ground vertical storage tank bottom plate surface.
Background
The bottom plate of the overground vertical steel storage tank is formed by welding and splicing steel plates with certain specifications and sizes one by one. The steel plate is directly placed on the storage tank cushion layer, and the cushion layer is formed by tamping or pouring different materials such as concrete, fine sand, backfill soil, asphalt sand, asphalt and the like according to the local geological structure and the bearing capacity requirement of the storage tank. Various types of corrosion such as crevice corrosion, oxygen concentration difference corrosion, microbial corrosion, chemical corrosion and the like can be generated between the storage tank bottom plate and the cushion layer contacted with the storage tank bottom plate. In order to prevent corrosion, protect the steel plate and prolong the service life of the storage tank, the bottom plate of the storage tank is generally protected by an anticorrosive layer or an anticorrosive layer combined with cathodic protection.
The anticorrosive coating protection method is to coat a layer of anticorrosive protective coating on the outer surface of the storage tank bottom plate, and to physically isolate the steel plate from a corrosive medium, so as to protect the storage tank bottom plate. There are two ways of cathodic protection: a forced current cathodic protection method and a sacrificial anode cathodic protection method. Both methods protect the tank floor by applying a cathodic protection dc current to the outer surface of the tank floor such that the tank floor steel is less negative than-0.85V (relative to the CSE reference electrode) to ground potential. The storage tank bottom plate is coated with the anticorrosive coating, so that the outer surface of the storage tank bottom plate is directly protected, the demand of cathodic protection current is reduced, and the consumption of electric energy is reduced; the cathodic protection can protect the leakage point and the pinhole of the anticorrosive coating, the damage point of the anticorrosive coating in construction and the damage point of the anticorrosive coating after aging. The two protection methods supplement each other and are the most widely adopted method in the anti-corrosion protection of the outer surface of the floor of the overground vertical storage tank at present.
In order to improve the quality of the anticorrosive coating and reduce the workload of manual coating on site, all steel plates need to be subjected to sand blasting and rust removal in a prefabrication factory and mechanically sprayed with the anticorrosive coating with specific components, structures and thicknesses. In order to reduce the damage of ablation and the like of the well-coated anticorrosive layer caused by high temperature during welding between the steel plates, the anticorrosive layer is not coated in advance in a welding heat affected zone of each steel plate with the width of about 5cm away from the edge, and the anticorrosive layer is removed by sand blasting and coated again after the whole storage tank is welded and the pressure test is qualified. The anti-corrosion process flow is suitable for the upper surface of the storage tank bottom plate, and after the steel plate is laid, the upper surface of the storage tank bottom plate has enough space to complete the subsequent operations. However, for the lower surface of the steel plate contacted with the cushion layer, after the whole tank bottom plate is welded and paved, no working space for recoating the anticorrosive coating exists, so that the heat affected zone of the lower surface of the storage tank bottom plate can only still keep the exposed state, and the anticorrosive coating cannot be protected.
The coated anticorrosive coating can age along with time, the peeling and aging conditions of the anticorrosive coating on the outer surface of the bottom plate of the storage tank are more and more serious along with the increase of the service life of the storage tank, more and more parts of exposed metal are provided, and the anticorrosive effect of the anticorrosive coating is poorer and poorer. A "cavity" is formed between the tank floor and the mat without direct physical contact. At this time, even if the cathode protection anode is mounted in the cushion layer under the storage tank bottom plate, the storage tank bottom plate at the position of the cavity cannot be protected and still is in a corrosion state because the cathode protection current cannot pass through the cavity to reach the outer surface of the storage tank bottom plate to be protected.
The reason for this "cavity" is due to several aspects: (1) no matter how advanced the process is and how strict the requirements are, the absolute level of the whole cushion layer cannot be achieved; the storage tank bottom plate formed by welding and splicing is formed by splicing a block of plate materials, and the absolute level of the whole bottom plate cannot be realized. When such two surfaces are in contact, there will inevitably be a "cavity" portion between them that is not in direct physical contact. (2) The tank is mainly intended for storage of media, but the amount of stored media is not constant but varies over time, sometimes more and sometimes less. For the storage tank with the cylindrical structure, under the influence of the gravity of the stored medium, the medium with different tank capacity heights can generate different pressures in different sizes and different directions on the storage tank wall plate and the storage tank bottom plate. The storage tank bottom plate adopts lamellar steel sheet welding to piece together and forms a big circular plane, and when the atress is uneven, corresponding physical deformation will take place for the different positions of storage tank bottom plate according to the size, the direction of atress, leads to the storage tank bottom plate to appear upwarping, empty drum, phenomenon such as collapsing. This will also cause a "cavity" to form between the reservoir floor and the mat. (3) According to the application of the storage tank and the geological structure of a construction area, the bottom plate of some storage tanks adopts a downward conical structure during construction, and a natural 'cavity' is generated between the bottom plate of the storage tank and a cushion layer of the conical structure and cannot be in effective physical contact; although the bottom plate of some storage tanks adopts a horizontal structure, the cushion layer below adopts an upward conical structure with a high middle part and a low periphery, so that a cavity is also generated between the periphery part of the bottom plate of the storage tank and the cushion layer, and effective physical contact cannot be formed.
Therefore, for the protection of the outer surface of the storage tank bottom plate, the problem that the storage tank bottom plate at the position of the cavity still cannot be effectively protected due to the cavity between the storage tank bottom plate and the cushion layer even if a combined protection method of an anticorrosive layer and cathode protection is adopted needs to be solved.
SUMMERY OF THE UTILITY MODEL
To the weak point that exists in the above-mentioned problem, the utility model provides a corrosion prevention device of ground vertical storage tank bottom plate surface realizes the comprehensive effectual anticorrosion protection of storage tank bottom plate through anticorrosive coating, cathodic protection system and corrosion inhibitor protection system.
In order to achieve the above object, the utility model provides an anti-corrosion device of ground vertical storage tank bottom plate surface, include:
the anticorrosive layer is coated on the outer surface of the bottom plate of the storage tank and is positioned in the area of each tank plate except the 5cm width range of the edge welding heat affected zone;
the cathode protection system is arranged in a cushion layer below the storage tank bottom plate and adopts a forced current cathode protection system or a sacrificial anode protection system;
the corrosion inhibitor protection system comprises a plurality of PVC porous pipes which are arranged in parallel to a storage tank bottom plate and a powdery gaseous corrosion inhibitor filled in the PVC porous pipes, wherein the end parts of two ends of each PVC porous pipe are sealed by sealing caps, and the PVC porous pipes are arranged in a cushion layer below the storage tank bottom plate or between the storage tank bottom plate and an impermeable membrane at the bottom of the storage tank.
As the utility model discloses further improve, a plurality of PVC porous pipes are on a parallel with the storage tank bottom plate and lay and be concentric ring-shaped or straight line shape, and all PVC porous pipes alternately switch on, and the crosspoint adopts the flexible joint intercommunication.
As a further improvement of the utility model, the corrosion inhibitor is a powdery solid substance which is freely transformed into a gas phase substance at the temperature of 0-50 ℃; the vapor pressure of the powdery vapor phase inhibitor is within the range of 10 at normal temperature-4-10-1Between handkerchief; the powdery vapor phase inhibitor is directly used or mixed with water to be slurry for use.
As a further improvement of the utility model, the gap between the edge plate of the storage tank and the concrete ring beam is sealed by mineral tape, viscoelastic adhesive tape or other elastomer materials.
As a further improvement of the utility model, the diameter of the PVC porous pipe is more than or equal to 25 mm; the diameter of the holes on the PVC porous pipe is between 2mm and 4mm, and the hole spacing is less than or equal to 50 mm.
As the utility model discloses further improve, the multilayer composite anticorrosive coating of one or more constitution in epoxy anticorrosive coating, phenol formaldehyde epoxy anticorrosive coating, modified epoxy anticorrosive coating and the inorganic zinc-rich anticorrosive coating is chooseed for use to the anticorrosive coating.
As the utility model discloses further improve, the impressed current cathodic protection system comprises potentiostat, a plurality of auxiliary anode, reference electrode and connecting cable, the potentiostat is installed outside the storage tank fire bank, auxiliary anode installs the position of 500mm apart from storage tank bottom plate lower surface or installs between the prevention of seepage membrane of storage tank bottom plate and storage tank bottoms, a plurality of auxiliary anode lay into netted or concentric ring form, the reference electrode is installed at storage tank central point position and storage tank edge, auxiliary anode with the reference electrode all through connecting cable with the potentiostat is connected, just connecting cable adopts copper welding or aluminium hot welding mode directly to be connected with storage tank edge board electricity.
As a further improvement of the utility model, the auxiliary anode is MMO anode with anode, MMO wire anode or conductive polymer wire anode, the net-shaped auxiliary anode is provided with a plurality of anode current feed points and is not less than 4, and each ring of the concentric ring-shaped auxiliary anode is provided with two anode current feed points;
the reference electrode is a double-reference electrode and comprises a high-purity zinc reference electrode and a copper sulfate reference electrode;
the connecting cable adopts a multi-strand cross-linked copper core cable, the outer surface of the connecting cable is coated with an anticorrosive layer and a protective layer, wherein the section of the test cable is more than or equal to 10mm2The cross section of the connecting cable of the cathode cable and the anode cable is more than or equal to 25mm2The cathode cable and the zero position cathode connecting cable are directly and electrically connected with the edge plate of the storage tank in a brazing or thermite welding mode, at least two connecting points of the cathode cable and the storage tank are arranged at intervals of 90 degrees or 180 degrees, the distance between the welding points of the cathode cable and the zero position cathode connecting cable and the edge plate of the storage tank is equal to or more than 100mm, and the welding points are sealed in an anti-corrosion mode.
As a further improvement of the utility model, the PVC porous pipe is installed at a position 100mm away from the lower surface of the storage tank bottom plate and keeps a certain distance with the auxiliary anode and the reference electrode of the cathodic protection system.
As a further improvement of the present invention, the sacrificial anode protection system comprises sacrificial anodes and a confluence cable, wherein a plurality of sacrificial anodes are embedded in a fine sand cushion layer under the storage tank bottom plate and are 500mm away from the lower surface of the storage tank bottom plate, chemical fillers are filled around the sacrificial anodes, all the sacrificial anodes are electrically connected with the storage tank bottom plate through the confluence cable, and the confluence cable passes through a threading conduit embedded in a concrete ring beam of the storage tank and is electrically connected with a storage tank edge plate;
the sacrificial anode is a zinc alloy sacrificial anode or a magnesium alloy sacrificial anode, the sacrificial anode is a plate-shaped, strip-shaped or block-shaped sacrificial anode, all sacrificial anodes are provided with tail cables, the tail cables of the sacrificial anode are electrically connected with a bus cable in a crimping mode, the bus cable is electrically connected with a storage tank edge plate in a brazing mode, and the sections of the bus cable and the tail cables of the sacrificial anode are larger than or equal to 10mm2。
The utility model has the advantages that:
the comprehensive and effective anti-corrosion protection of the storage tank bottom plate is realized through the anti-corrosion layer, the cathode protection system and the corrosion inhibitor protection system. The corrosion-resistant layer physically isolates the storage tank bottom plate from a corrosive medium by adopting a direct isolation method so as to provide protection; the cathode protection system solves the problem of corrosion protection when the storage tank bottom plate is in direct physical contact with the cushion layer; the corrosion inhibitor protection system solves the problems that the storage tank bottom plate is not in direct physical contact with the cushion layer, and the corrosion protection is realized when a cavity exists.
Drawings
Fig. 1 is a schematic view of a mesh-laid impressed current cathodic protection system according to an embodiment of the present invention;
fig. 2 is a schematic view of a forced current cathodic protection system laid in a ring shape according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a sacrificial anode protection system using plate-shaped sacrificial anodes according to an embodiment of the present invention;
FIG. 4 is a schematic view of a sacrificial anode protection system using a strip-shaped sacrificial anode according to an embodiment of the present invention;
FIG. 5 is a schematic view of a sacrificial anode protection system using a bulk sacrificial anode according to an embodiment of the present invention;
FIG. 6 is a schematic view of the tank bottom layout of the storage tank according to an embodiment of the present invention;
FIG. 7 is a schematic view of a PVC perforated pipe according to an embodiment of the present invention;
fig. 8 is a schematic view of a PVC perforated pipe arranged concentrically and annularly according to an embodiment of the present invention;
fig. 9 is a schematic view of a PVC perforated pipe linearly arranged according to an embodiment of the present invention.
In the figure, the position of the upper end of the main shaft,
1. a potentiostat; 2. an auxiliary anode; 3. a reference electrode; 4. connecting a cable; 5. a tank foundation bed course; 6. a sacrificial anode; 7. a bus cable; 8. a PVC perforated pipe; 9. an impermeable membrane; 10. a storage tank floor; 11. a storage tank wall panel; 12. a sealing cap; 13. a flexible joint.
Detailed Description
The embodiment of the utility model provides an anti corrosion device of ground vertical storage tank bottom plate surface, include: anticorrosive coating, cathodic protection system and corrosion inhibitor protection system. The anticorrosive layer physically isolates the storage tank bottom plate from a corrosive medium by adopting a direct isolation method to provide protection; the cathode protection system solves the problem of corrosion protection when the storage tank bottom plate is in direct physical contact with the cushion layer; the corrosion inhibitor protection system solves the problems that the storage tank bottom plate is not in direct physical contact with the cushion layer, and the corrosion protection is realized when a cavity exists.
The three sections will be described in detail separately below.
(1) Anticorrosive coating
The anticorrosive coating is coated on the outer surface of the storage tank bottom plate, and the anticorrosive coating directly physically isolates corrosive media of the storage tank bottom plate.
Because the storage tank bottom plate is formed by welding and splicing a plurality of steel plates, each steel plate needs to be subjected to surface treatment before being coated with the anticorrosive coating. The outer surface of the steel plate is subjected to sand blasting/shot blasting to achieve Sa2.5 grade or better; the anchor line depth is between 40 and 100 mu m; after rust removal, surface cleanliness treatment is carried out to reach 2-grade or better grade; the residual amount of soluble chloride on the surface is not higher than 5 mu g/cm2. After the storage tank bottom plate is treated to meet the requirements, the anticorrosive coating is immediately coated, the longest interval time is not more than 4h, and when rust return or pollution occurs, the rust removal work is carried out again even within 4 h.
According to the operating temperature of the storage tank, an epoxy anticorrosive coating, a novolac epoxy anticorrosive coating, a modified epoxy anticorrosive coating, an inorganic zinc-rich anticorrosive coating or an anticorrosive coating with a multi-layer composite structure is selected. Wherein, when the two-component paint is coated, a special stirrer is adopted to stir and mix the paint, and proper curing time is given. The prepared coating should be used within the working life, and the coating exceeding the working life is forbidden. When the anticorrosive coating adopts a multilayer composite structure, the coating interval time between layers is executed according to different requirements of different coatings. The coating of the anticorrosive coating adopts a mechanical operation mode, the coating work of the whole anticorrosive coating is completed in a prefabrication factory, and the anticorrosive coating is not coated or only the workshop primer coating which has no influence on the anticorrosive coating is coated in the width range of 5cm of the welding heat affected zone at the edge of each tank plate. By adopting the mechanical prefabrication mode, better anticorrosion quality is provided, and manual coating on site is not needed. According to the corrosion grade and the corrosion-resistant service life requirement of the storage tank cushion medium, the thickness of the corrosion-resistant layer is different, and the total thickness of the tank plate coating corrosion-resistant layer at other positions except the welding heat affected area is more than or equal to 200 mu m.
(2) Cathodic protection system
The cathode protection system is arranged in the cushion layer below the storage tank bottom plate, so that the corrosion protection is realized when the storage tank bottom plate is in direct physical contact with the cushion layer.
The cathodic protection system generally adopts a forced current cathodic protection system, and when the diameter of the storage tank is less than 8m, the cathodic protection system adopts a sacrificial anode protection system.
As shown in fig. 1-2, the impressed current cathodic protection system consists of a potentiostat 1, a plurality of auxiliary anodes 2, a reference electrode 3 and a connecting cable 4. Potentiostat 1 installs outside the storage tank fire bank, and supplementary positive pole 2 is installed at the position apart from storage tank bottom plate lower surface 500mm, and when the prevention of seepage membrane 9 was installed to the storage tank bottom, supplementary positive pole 2 was installed between the prevention of seepage membrane of storage tank bottom plate and storage tank bottom. A plurality of auxiliary anodes 2 are laid into a net shape or a concentric ring shape, a reference electrode 3 is arranged at the central point position and the edge of the storage tank, and the auxiliary anodes 2 and the reference electrode 3 are both connected with a constant potential rectifier 1 through a connecting cable 4.
Wherein, auxiliary anode 2 chooses MMO area positive pole, MMO line positive pole or conducting polymer line positive pole for use, and netted auxiliary anode sets up a plurality of anode current feed points and is no less than 4, and concentric ring form auxiliary anode's every ring all sets up two anode current feed points.
The reference electrode 3 adopts double reference electrodes, including a high-purity zinc reference electrode and a copper sulfate reference electrode. The two reference electrodes have enough space to avoid the mutual influence of the ground electric fields; the reference electrodes are arranged at the central point of the storage tank and near the edge of the storage tank, a plurality of reference electrodes are arranged according to the area of the bottom plate of the storage tank, and each reference electrode is not less than 2.
The connecting cable 4 adopts a multi-strand cross-linked copper core cable, the outer surface of which is coated with an anticorrosive layer and a protective layer, wherein the section of the test cable (the connecting cable for testing) is more than or equal to 10mm2The cross section of the connecting cable of the cathode cable (connecting cable for connecting the cathode) and the anode cable (connecting cable for connecting the auxiliary anode) is more than or equal to 25mm2Cathode cable and zero grounding cathode cable (for)Connecting cables connected with a potentiostat and a zero position cathode) are directly and electrically connected with the edge plate of the storage tank by adopting a brazing or thermite welding mode, at least two connecting points of the cathode cable and the storage tank are arranged at intervals of 90 degrees or 180 degrees, the distance between the cathode cable and the welding point of the zero position cathode cable and the edge plate of the storage tank is more than or equal to 100mm, and the welding point is sealed for corrosion prevention.
As shown in fig. 3-5, the sacrificial anode protection system consists of a sacrificial anode 6 and a bus cable 7. A plurality of sacrificial anodes 6 are buried in the fine sand cushion layer below the storage tank bottom plate and are 500mm away from the lower surface of the storage tank bottom plate. The sacrificial anode 6 is filled with a chemical filler of sufficient size. All sacrificial anodes 6 are electrically connected with the storage tank bottom plate through the confluence cables 7, and the confluence cables 7 penetrate through the threading guide pipes pre-buried in the storage tank concrete ring beam to be electrically connected with the storage tank edge plate.
The sacrificial anode 6 is a zinc alloy sacrificial anode or a magnesium alloy sacrificial anode, and is in a plate, strip or block shape. The weight of the sacrificial anodes 6 is such as to meet the design life requirements, all of which are equipped with a sufficient length of the tail cable. The tail cable of the sacrificial anode 6 is electrically connected with the bus cable 7 in a crimping mode, the bus cable 7 is electrically connected with the edge plate of the storage tank in a brazing mode, and the sections of the bus cable 7 and the tail cable of the sacrificial anode 6 are more than or equal to 10mm2。
(3) Corrosion inhibitor protection system
The corrosion inhibitor protection system comprises a plurality of PVC porous pipes 8 arranged in parallel with a storage tank bottom plate 10 and powdery gaseous corrosion inhibitors filled inside the PVC porous pipes 8, wherein the corrosion inhibitors are filled in the PVC porous pipes 8 and are slowly released. As shown in fig. 6, the PVC porous pipe 8 is installed in the mat layer below the storage tank bottom plate 10 at a position spaced about 100mm from the lower surface of the storage tank bottom plate. When the anti-seepage film 9 is arranged at the bottom of the storage tank, the PVC porous pipe 8 is arranged between the storage tank bottom plate 10 and the anti-seepage film 9 at the bottom of the storage tank. When the PVC porous pipe 8 is installed, enough space is kept between the PVC porous pipe and objects such as the auxiliary anode 2, the reference electrode 3 and the like. In addition, when the PVC porous pipe 8 is installed, the outer surface of the PVC porous pipe 8 is wrapped by two layers of geotextile, so that the pipeline is prevented from being blocked by sand and broken stones during backfilling, the PVC porous pipe 8 positioned below the storage tank is provided with enough holes, and the PVC porous pipe 8 which exceeds the concrete ring beam of the storage tank is not provided with holes. The ends of both ends of each PVC porous pipe 8 are sealed by sealing caps 12.
As shown in FIG. 7, the diameter of the PVC porous pipe 8 is more than or equal to 25 mm; the diameter of the holes on the PVC porous pipe 8 is between 2mm and 4mm, and the hole spacing is less than or equal to 50 mm.
As shown in fig. 8 to 9, the PVC perforated pipe 8 may be arranged in a concentric ring shape parallel to the tank bottom plate 10, or may be arranged in a straight line shape parallel to the tank bottom plate 10. No matter the PVC porous pipes are concentric rings or straight lines, all the PVC porous pipes 8 are crossed and communicated, the cross points are communicated by adopting flexible joints 13, and the spacing distance between every two adjacent PVC porous pipes 8 is less than or equal to 2 m.
The vapor phase corrosion inhibitor is also named as vapor phase rust preventive powder. The gas phase rust-proof powder is a water-soluble rust-proof powder which can be used for both dry and wet purposes. The method is mainly used for the rust prevention treatment of the internal metal surface of a metal dent, a hollow or a cavity. In a closed space, the dry gas-phase rust-proof powder is used, and the rust-proof effect is excellent. After being gasified, the gas-phase rust-preventive powder is adsorbed on the surface of the metal to form a dense protective film layer, thereby playing a role in rust prevention.
The corrosion inhibitor of the utility model is a powdery solid substance which can be freely transformed into a gas phase substance at the temperature of 0-50 ℃; the vapor pressure of the powdery vapor phase inhibitor is within the range of 10 at normal temperature-4-10-1Between handkerchief; the powdery vapor phase inhibitor is directly used or mixed with water to be slurry for use. The corrosion inhibitor can play a role in corrosion prevention under the liquid or gaseous state; when the corrosion inhibitor is adsorbed on the lower surface of the storage tank bottom plate, products formed by the corrosion inhibitor body and the corrosion inhibitor are compatible with cathodic protection, and can not generate cathodic depolarization.
When the corrosion inhibitor is filled, the powdery vapor phase corrosion inhibitor and water can be mixed into slurry for use. And opening the sealing caps 12 for sealing the end parts of all the PVC porous pipes 8, filling the PVC porous pipes 8 by utilizing the self-flowing characteristic of pulp or injecting the PVC porous pipes 8 by adopting a grouting machine, wherein the injection amount is preferably equal to that of the visible corrosion inhibitor pulp in the end parts of other PVC porous pipes 8 except the grouting pipe, and timely sealing the sealing caps 12 for sealing the end parts of the PVC porous pipes 8 after the filling is finished.
Furthermore, the gap between the edge plate of the storage tank and the concrete ring beam is sealed by mineral tape, viscoelastic tape or other elastomer materials, so that ineffective volatilization of the corrosion inhibitor is avoided. In addition, the sealing cap 12 at the end of the PVC perforated pipe 8 is opened periodically to observe the amount of the corrosion inhibitor, and if the amount of the corrosion inhibitor is found to be lack, the corrosion inhibitor of the same type, brand and supplier is injected or filled in time.
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 (10)
1. An anti-corrosion device for the outer surface of the bottom plate of an underground vertical storage tank, comprising:
the anticorrosive layer is coated on the outer surface of the bottom plate of the storage tank and is positioned in the area of each tank plate except the 5cm width range of the edge welding heat affected zone;
the cathode protection system is arranged in a cushion layer below the storage tank bottom plate and adopts a forced current cathode protection system or a sacrificial anode protection system;
the corrosion inhibitor protection system comprises a plurality of PVC porous pipes (8) which are arranged in parallel to a storage tank bottom plate (10) and powdery gaseous corrosion inhibitors filled in the PVC porous pipes (8), wherein the end parts of two ends of each PVC porous pipe (8) are sealed by sealing caps (12), and the PVC porous pipes (8) are arranged in a cushion layer below the storage tank bottom plate (10) or arranged between the storage tank bottom plate (10) and an anti-seepage film (9) at the bottom of the storage tank.
2. The corrosion prevention device according to claim 1, wherein a plurality of PVC porous pipes (8) are arranged in parallel to the tank bottom plate (10) and are in concentric ring shape or straight line shape, all the PVC porous pipes (8) are communicated in a cross way, and the cross points are communicated by flexible joints (13).
3. The corrosion protection device of claim 1, wherein the corrosion inhibitor is a solid substance in powder form, free to transform into a gaseous substance at a temperature of 0 ℃ to 50 ℃; the vapor pressure of the powdery vapor phase inhibitor is within the range of 10 at normal temperature-4-10-1Between handkerchief; the powdery vapor phase inhibitor is directly used or mixed with water to be slurry for use.
4. The corrosion protection device of claim 1, wherein the gap between the rim plate of the tank and the concrete collar is sealed by mineral tape, viscoelastic tape, or other elastomeric material.
5. The anti-corrosion device according to claim 1, characterized in that the diameter of the PVC perforated pipe (8) is not less than 25 mm; the diameter of the holes on the PVC porous pipe (8) is between 2mm and 4mm, and the hole spacing is less than or equal to 50 mm.
6. The corrosion protection device of claim 1, wherein said corrosion protection layer is a multi-layer composite corrosion protection layer comprising one or more of epoxy corrosion protection layer, novolac epoxy corrosion protection layer, modified epoxy corrosion protection layer, and inorganic zinc-rich corrosion protection layer.
7. Anti-corrosion device according to claim 1, characterized in that the impressed current cathodic protection system consists of a potentiostat (1), of a plurality of auxiliary anodes (2), of a reference electrode (3) and of a connecting cable (4), the potentiostat (1) is arranged outside the storage tank fire dike, the auxiliary anodes (2) are arranged at a position 500mm away from the lower surface of the storage tank bottom plate or between the storage tank bottom plate and an impermeable film at the bottom of the storage tank, a plurality of auxiliary anodes (2) are laid into a net shape or a concentric circular shape, the reference electrode (3) is arranged at the central point position and the edge of the storage tank, the auxiliary anode (2) and the reference electrode (3) are both connected with the potentiostat (1) through a connecting cable (4), and the connecting cable (4) is directly and electrically connected with the storage tank edge plate in a brazing or thermite welding mode.
8. The corrosion protection device according to claim 7, wherein the auxiliary anode (2) is selected from an MMO strip anode, an MMO wire anode or a conductive polymer wire anode, a plurality of anode current feed points are arranged on a net-shaped auxiliary anode, and the number of the anode current feed points is not less than 4, and two anode current feed points are arranged on each ring of the concentric circular auxiliary anode;
the reference electrode (3) adopts double reference electrodes, including a high-purity zinc reference electrode and a copper sulfate reference electrode;
the connecting cable (4) adopts a multi-strand cross-linked copper core cable, the outer surface of which is coated with an anticorrosive layer and a protective layer, wherein the section of the test cable is more than or equal to 10mm2The cross section of the connecting cable of the cathode cable and the anode cable is more than or equal to 25mm2The cathode cable and the zero position cathode connecting cable are directly and electrically connected with the edge plate of the storage tank in a brazing or thermite welding mode, at least two connecting points of the cathode cable and the storage tank are arranged at intervals of 90 degrees or 180 degrees, the distance between the welding points of the cathode cable and the zero position cathode connecting cable and the edge plate of the storage tank is equal to or more than 100mm, and the welding points are sealed in an anti-corrosion mode.
9. The anti-corrosion device according to claim 7, characterized in that the PVC perforated pipe (8) is installed at a distance of 100mm from the lower surface of the tank floor (10) and is spaced apart from the auxiliary anode (2) and the reference electrode (3) of the cathodic protection system.
10. The corrosion protection device according to claim 1, wherein the sacrificial anode protection system is composed of sacrificial anodes (6) and a confluence cable (7), a plurality of sacrificial anodes (6) are buried in a fine sand cushion layer below the bottom plate of the storage tank and are 500mm away from the lower surface of the bottom plate of the storage tank, chemical fillers are filled around the sacrificial anodes (6), all the sacrificial anodes (6) are electrically connected with the bottom plate of the storage tank through the confluence cable (7), and the confluence cable (7) passes through a threading guide pipe pre-embedded in a concrete ring beam of the storage tank and is electrically connected with a storage tank edge plate;
the sacrificial anode (6) is a zinc alloy sacrificial anode or a magnesium alloy sacrificial anode, and is in the shape of a plate, a strip or a blockThe sacrificial anode is provided with a tail cable, the tail cable of the sacrificial anode is electrically connected with a bus cable (7) in a crimping mode, the bus cable (7) is electrically connected with a storage tank edge plate in a brazing mode, and the sections of the bus cable (7) and the tail cable of the sacrificial anode (6) are more than or equal to 10mm2。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920710350.5U CN210176957U (en) | 2019-05-17 | 2019-05-17 | Anti-corrosion device for outer surface of bottom plate of underground vertical storage tank |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920710350.5U CN210176957U (en) | 2019-05-17 | 2019-05-17 | Anti-corrosion device for outer surface of bottom plate of underground vertical storage tank |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113266023A (en) * | 2021-05-31 | 2021-08-17 | 河北地质大学 | Ecological slope protection soil stabilization structure and method |
| CN115466961A (en) * | 2022-10-17 | 2022-12-13 | 东南大学 | Cathode protection anti-corrosion device for sacrificial anode of flexible photovoltaic support |
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2019
- 2019-05-17 CN CN201920710350.5U patent/CN210176957U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113266023A (en) * | 2021-05-31 | 2021-08-17 | 河北地质大学 | Ecological slope protection soil stabilization structure and method |
| CN115466961A (en) * | 2022-10-17 | 2022-12-13 | 东南大学 | Cathode protection anti-corrosion device for sacrificial anode of flexible photovoltaic support |
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