Anode bed system for heavy corrosion environment and construction method thereof

Abstract

The present application relates to a kind of heavy corrosion environment anode bed system and its construction method, system includes anode assembly, anode assembly includes support frame, corrosion-resistant frame and at least 2 coaxial butt joint platinum titanium composite tube or platinum niobium composite tube anode body fixed between the two, support frame includes top cover plate, bottom cover plate and four fixed support column between the two, corrosion-resistant frame includes upper cover plate, lower cover plate, support column and positioning column, support column, positioning column are fixedly connected with upper cover plate, lower cover plate;Upper, lower, top, bottom cover plate coaxial arrangement and same diameter;Anode body is fixedly connected with positioning column and middle part is evenly distributed with 2-3 anode lead wire welded in circumference, anode lead wire is connected ground terminal box after being led out from the welding point of anode body.The present application is to provide a kind of heavy corrosion environment anode bed system and its construction method in severe coastal corrosion environment, which can provide efficient current output, high reliability and long service life.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of metal corrosion protection by sacrificial anode or impressed current cathodic protection method, in particular to an anode bed system for heavy corrosion environment and a construction method thereof. BACKGROUND

[0002] In the coastal environment, the corrosion of equipment and facilities is very serious. Industry experts have been working hard to find better solutions, including better corrosion protection effect, more reliable and longer life corrosion protection technology measures. The corrosion protection measures of coastal facilities usually adopt coating protection and cathodic protection. Cathodic protection includes sacrificial anode cathodic protection method and impressed current cathodic protection method. The impressed current cathodic protection method mainly consists of anode bed, anode lead, junction box, anode cable, controller and power supply, cathode cable, reference electrode cable and cathode grounding cable. The function of the anode bed is to provide sufficient cathodic protection current for the protected facilities through the controller and power supply. However, in the coastal environment, the anode bed is usually at a positive potential of tens of volts or even hundreds of volts when working, which leads to the anode and the anode lead, anode cable and other parts being in extremely severe corrosion conditions, thus greatly reducing the effective service life of the anode bed. SUMMARY

[0003] The present application provides an anode bed system for heavy corrosion environment which can provide high-efficiency current output, high reliability and long service life in the severe coastal corrosion environment.

[0004] The present application provides an anode bed system for heavy corrosion environment, which comprises an anode lead and a ground junction box, and further comprises an anode assembly, wherein the anode assembly comprises a support frame, a corrosion-resistant frame and at least two coaxially butted anode bodies fixed between the support frame and the corrosion-resistant frame, the anode bodies are platinum-titanium composite pipes or platinum-niobium composite pipes, and the anode lead is a silver wire.

[0005] The support frame comprises a top cover plate, a bottom cover plate and four fixed columns supported between the top cover plate and the bottom cover plate, and the corrosion-resistant frame comprises an upper cover plate, a lower cover plate, a support column and a positioning column, wherein the support column and the positioning column are fixedly connected to the upper cover plate and the lower cover plate by bolts.

[0006] The upper cover plate, the lower cover plate, the top cover plate and the bottom cover plate are coaxially arranged and have the same diameter.

[0007] The anode bodies are fixedly connected to the positioning columns, 2-3 anode leads are circumferentially welded to the middle part of each anode body, four through holes are arranged on the combination of the top cover plate and the upper cover plate, two of the through holes serve as threading channels for the anode leads, the anode leads are first wound around the upper cover plate after being led out from the welding points of the anode bodies, then are wound to the lower cover plate along the wire protection pipe, and finally are led out from the through holes through the wire protection pipe and connected to the ground junction box.

[0008] In some embodiments, the anode assembly further comprises several exhaust pipes, which comprise an assembly inner section, an assembly outer section, and both are connected by a sleeve or by hot melt bonding, the assembly inner section is uniformly arrayed with exhaust holes on the surface and is provided with a blocking head at the bottom.

[0009] In some embodiments, the assembly inner section of the exhaust pipe is covered with a corrosion-resistant cloth, and the aperture or the wire weaving spacing of the cloth is 150-230 um, the corrosion-resistant cloth is fixed by a binding tape, and the exhaust pipe, the sleeve, the blocking head, the corrosion-resistant cloth, and the binding tape are all made of polytetrafluoroethylene material.

[0010] In some embodiments, the exhaust pipe is provided with a protective net at the end near the wellhead to prevent insects or foreign matters from entering, and is additionally provided with a U-shaped downpipe.

[0011] In some embodiments, it further comprises a bolt and a nut made of polytetrafluoroethylene material and two sets of clamps, the middle section of the clamp is arc-shaped and adapted to the shape of the anode body, the two ends are flat plates, through holes are arranged on the arc-shaped part, the flat plate part, and the positioning column, and two sets of clamps are symmetrically arranged along the radial direction of the anode body to clamp the anode body and are fixed by the bolt and the nut and the positioning column.

[0012] In some embodiments, the lug is threadedly connected or welded to the top cover plate.

[0013] In some embodiments, the top cover plate, the bottom cover plate, the stand, and the lug are all made of 316L stainless steel material, and the surface of the support frame is coated with an epoxy anticorrosive paint coating.

[0014] In some embodiments, the top cover plate, the bottom cover plate, the positioning column, and the bolt are made of polytetrafluoroethylene material, and the support column is a carbon fiber tube with a polytetrafluoroethylene column inside.

[0015] Another aspect of the present application provides a closed hole construction method of the above-mentioned anode ground bed system for heavy corrosion environment, comprising the following steps:

[0016] ① Installing the support frame: the two ends of the four stand columns uniformly distributed along the circumference of the top cover plate are respectively passed through the top cover plate and the bottom cover plate and are welded with the top cover plate and the bottom cover plate;

[0017] ② Installing the corrosion-resistant frame: the top cover plate and the bottom cover plate are pushed to be tightly attached to the top cover plate and the bottom cover plate at both ends, and the support column and the positioning column are fixed by the bolt between the top cover plate and the bottom cover plate;

[0018] ③ Installing the anode body: the three anode bodies are coaxially butt-jointed, and each anode body is fixed by the bolt, the nut, the two sets of clamps, and the positioning column;

[0019] (4) Install anode lead, exhaust pipe: Weld 2 to 3 anode leads at the middle of each anode body along its circumference, and cover the welding points and the end of the insulating layer of the anode lead with asphalt for corrosion protection and sealing. The combination of the top cover plate and the upper cover plate is provided with 4 through holes, two of which serve as the threading channel for the anode lead. The anode lead is first routed to the vicinity of the upper cover plate, then to the vicinity of the lower cover plate along the exhaust pipe, and then is led out of the through hole through the wire protection pipe. Two exhaust pipes are arranged on both sides of the anode body, and the inner section of the exhaust pipe combination and the corrosion-resistant cloth are installed.

[0020] (5) Drilling: Drill the well using the circulating water displacement mud method. After installation, the anode combination is below the water layer, and there are carbonaceous filler layers around the anode body and above and below the anode combination. There is a gravel layer between the wellhead and the filler.

[0021] (6) Pump out the mud in the well and put it into the carbonaceous filler below the anode combination: The filler is pre-soaked with water or mixed with water to form a slurry, and then the soaked filler or the slurry is pumped into the well. The target thickness of the filler in the well is 1m to 1.5m, ensuring that the filler is densely packed.

[0022] (7) Hoist and put into the anode combination: The crane uses the lifting lugs of the anode combination to send the anode combination into the wellhead. At the wellhead, the inner section of the exhaust pipe combination is bonded to the outer section of the combination by casing or hot melting. The anode lead and wire protection pipe leading out of the anode combination are straightened. The crane then sends the anode combination into the well.

[0023] (8) Put carbonaceous filler around the anode body and above the anode combination: The filler is pre-mixed with water to form a slurry, and then the slurry is pumped into the well. The target thickness of the filler in the well is more than 1m to 1.5m above the top surface of the anode combination, ensuring that the filler is densely packed around the anode body and above the anode combination. After the filler settles, gravel is put in and filled to the ground.

[0024] (9) Brick or cement protection pipe well cementation: Insert a cement protection pipe into the gravel layer at the wellhead, and the exhaust pipe and anode lead all pass through the cement protection pipe to extend outward. A permanent bed marker pile is set at the deep well anode bed.

[0025] (10) Ground terminal box and cable installation: The section of the anode lead from the top end of the cement protection pipe to the ground terminal box is increased by a hot-dipped galvanized metal wire protection pipe and buried underground. The surface of the ground terminal box and the metal wire protection pipe is coated with epoxy anticorrosive paint. The anode lead at the inlet of the ground terminal box and the anode cable at the outlet are connected to a silver plate, and the surface of the screw, nut and gasket of the terminal screw is plated with silver. An insulating support is provided between the bus bar and the shell of the ground terminal box. The cable inlet and outlet of the ground terminal box body are insulated and sealed.

[0026] In some embodiments, in the step ②, two positioning columns are arranged in the middle, four supporting columns are arranged on both sides of the positioning columns in pairs, and the anode body is located between the two positioning columns.

[0027] Based on the above technical scheme, the anode bed system has the characteristics of high corrosion resistance structure, high corrosion resistance of the anode and lead wire, low anode grounding resistance, and large anode current density, and in the serious coastal corrosion environment, the anode bed system has high reliability, long service life, can provide high-efficiency current output, and has the structural strength before installation and the structural integrity, functional reliability during the long service life after installation. Therefore, the anode bed system for heavy corrosion environment and the construction method thereof are used in the impressed current cathodic protection system, and can solve the corrosion problem of coastal equipment and facilities, especially the serious corrosion problem of the seawater cooling metal pipe network of the nuclear power plant. BRIEF DESCRIPTION OF DRAWINGS

[0028] The drawings in the application serve to supplement the description in the text part of the description, and further explain the technical scheme of the application, and do not constitute improper limitation on the application.

[0029] Figure 1 It is a schematic diagram of the installation state of the anode bed system for heavy corrosion environment in the application;

[0030] Figure 2 It is a schematic diagram of the installation state of the anode bed system for heavy corrosion environment in the application; Figure 1 It is a partial enlarged view of I in the middle;

[0031] Figure 3 It is a schematic diagram of the structure of the anode assembly in the application;

[0032] Figure 4 It is a top view of the anode assembly in the application;

[0033] Figure 5 It is a bottom view of the anode assembly in the application;

[0034] Figure 6 It is a schematic diagram of the structure of the anode assembly in the application; Figure 4 A-A sectional view of;

[0035] Figure 7 It is a top view of the upper cover plate in the application;

[0036] Figure 8 It is a top view of the lower cover plate in the application;

[0037] Figure 9 It is a schematic diagram of the structure of the clamp in the application;

[0038] Figure 10 It is a front view of the anode assembly in the application;

[0039] Figure 11 It is aFigure 10 Close-up view at II. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings.

[0041] In the description of the present application, it should be understood that the terms "center", "transverse", "longitudinal", "front", "back", "left", "right", "up", "down", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the scope of protection of the present application.

[0042] As Figure 1 shown, according to the geological conditions of the installation site of the anode bed, the anode assembly 1 of the present application can select different installation methods, each anode assembly 1 can adopt the installation method of deep well anode bed, or can adopt the installation method of shallow buried anode bed, and the anode assembly 1 can even be placed in a seawater channel, a pond, or the sea. According to the current size of the impressed current cathodic protection required by the specific facility, the installation method of the anode bed, and the impedance size of the installation site of the anode bed, a certain number of anode assemblies 1 are selected to ensure that the anode bed system can provide sufficient cathodic protection current.

[0043] The installation method of the shallow buried anode bed has a horizontal type and a vertical type, the anode assembly 1 should be installed below the frozen soil layer, and the burial depth should not be less than 1m, the anode assembly 1 and the surrounding 200-300mm range should be filled with carbon filler, and the first and last ends of the shallow buried anode bed should be provided with permanent bed identification piles.

[0044] When the anode assembly 1 is placed in a seawater channel, a pond, or the sea, no exhaust pipe 14 is needed, and no filler is needed.

[0045] The installation mode of the deep well anode bed includes the open hole method and the closed hole method. The open hole method is an installation mode in which the anode is surrounded by the aqueous electrolyte. The open hole method does not need the exhaust pipe 14 and the filler. The non-metal sleeve should be used in the active area of the open hole anode bed. The sleeve should have the rigidity and strength requirements for resisting the collapse of the well wall and other external force damage. The sleeve must be perforated to facilitate the current discharge and the entry of the aqueous electrolyte. The closed hole method is an installation mode in which the anode is filled with carbonaceous filler. The carbonaceous filler is usually metallurgical coke, calcined petroleum coke, graphite and the like. The filler has the permeability and electrical conductivity. The smaller the particle size of the filler is, the more unfavorable the permeability is. The larger the particle size of the filler is, the more unfavorable the electrical conductivity is. The good permeability is beneficial to the entry of the aqueous electrolyte, the reduction of the grounding resistance and the gas discharge, and the prevention of the gas resistance. The particle size of the filler is preferably in the range of 0.3mm to 1mm. The minimum particle size of the filler is greater than the hole diameter of the corrosion-resistant cloth or the wire spacing. The entry of the material from the exhaust hole can be reduced, and the excessive entry of the material into the exhaust pipe can be prevented to cause the blockage and the loss of the exhaust function. Each anode lead 2 should have obvious identification or use the color of the insulating layer as the identification, and correspond to the installation position of the connected anode body on the anode assembly 1. The length of each anode lead 2 is preferably greater than or equal to 5m from the well mouth. The thickness of the filler layer below the anode assembly 1 is preferably greater than or equal to 1m, and the filling is ensured to be dense. The thickness of the filler layer above the anode assembly 1 is preferably greater than or equal to 1m, and the filling is ensured to be dense. The gravel layer with good water permeability is filled again. The thickness of the gravel layer is preferably greater than or equal to 1m, and the particle size is preferably in the range of 10mm to 50mm.

[0046] For example Figures 1-3 as shown in the drawings, an anode bed system for heavy corrosion environment includes an anode assembly 1, an anode lead 2 and a ground terminal box 3. The anode assembly 1 includes a support frame 11, a corrosion-resistant frame 12 and at least two coaxially butted anode bodies 13 fixed between the support frame 11 and the corrosion-resistant frame 12. The anode body 13 is a platinum-titanium composite pipe or a platinum-niobium composite pipe. The anode lead 2 is a silver wire.

[0047] For example Figure 1 , Figures 3-5 and Figure 10 , Figure 11As shown, the support frame 11 includes a top cover plate 101, a bottom cover plate 102, and four fixed support columns 103 between the two, the corrosion-resistant frame 12 includes an upper cover plate 121, a lower cover plate 122, a support column 123 and a positioning column 124, the support column 123 and the positioning column 124 are fixedly connected with the upper cover plate 121 and the lower cover plate 122 through bolts 125, and the upper cover plate 121, the lower cover plate 122, the top cover plate 101 and the bottom cover plate 102 are coaxially arranged and have the same diameter. The anode body 13 is fixedly connected with the positioning column 124, and 2-3 anode lead wires 2 are evenly welded on the middle part of the anode body 13 in the circumferential direction. A combination of the top cover plate 101 and the upper cover plate 121 is provided with four through holes 1011, two of which serve as threading channels for the anode lead wires 2. The anode lead wires 2 are first wound around the vicinity of the upper cover plate 121 after being led out from the welding points of the anode body 13, then are wound to the vicinity of the lower cover plate 122 along the wire protection tube 21, and then are led out from the through holes 1011 through the wire protection tube 21 and connected with the ground terminal box 3. In order to facilitate the connection of the crane, the top cover plate 101 is threadedly connected or welded with lifting lugs 104. The top cover plate 101, the bottom cover plate 102, the support column 103 and the lifting lug 104 are all made of 316L stainless steel material, which has high reliability. At the same time, the surface of the support frame 11 is coated with an epoxy anticorrosive paint coating to prolong the service life. Similarly, in order to prolong the service life, the upper cover plate 121, the lower cover plate 122, the positioning column 124 and the bolt 125 are made of polytetrafluoroethylene material, and the support column 123 is a carbon fiber tube with a polytetrafluoroethylene column inside. The carbon fiber tube not only increases the structural strength, but also has the functions of electrical conductivity and corrosion resistance.

[0048] Again, as shown in the drawings, Figure 1 , Figure 2 , Figure 6 , Figure 11 As shown, the anode assembly 1 further includes a plurality of exhaust pipes 14, the exhaust pipe 14 includes an assembly inner section 141 and an assembly outer section 142, and the two are connected through a sleeve 143 or are bonded by heat melting, the assembly inner section 141 is arrayed with exhaust holes 144 and is provided with a blocking head at the bottom. Preferably, in order to reduce the entry of foreign matter from the exhaust holes 144 and prevent the exhaust pipe 14 from being blocked due to too much foreign matter entering the exhaust pipe 14 and losing the exhaust function, the assembly inner section 141 of the exhaust pipe 14 is covered with a corrosion-resistant cloth, and the aperture or the wire weaving spacing of the cloth is 150-230 um, which allows gas to pass through and reduces the size of the possible entering matter as much as possible. The corrosion-resistant cloth is fixed by a binding band, and the exhaust pipe 14, the sleeve 143, the blocking head, the corrosion-resistant cloth and the binding band are all made of polytetrafluoroethylene material. Preferably, the exhaust pipe 14 is provided with a protective net near the end of the wellhead 6 to prevent insects or foreign matter from entering, and is additionally provided with a U-shaped downward pipe 145, and the protective net and the U-shaped downward pipe 145 are preferably made of polytetrafluoroethylene material.

[0049] As shown in the drawings, Figure 3 , Figure 9As shown, the anode bed system for heavy corrosion environment of the present application further comprises corrosion-resistant bolts and nuts made of polytetrafluoroethylene material and two sets of clamps 131, the middle section of the clamp 131 is arc-shaped to match the shape of the anode body 13, and the two ends are flat plates, and through holes are arranged on the arc-shaped part, the flat plate part and the positioning column 124, two sets of clamps 131 are arranged radially symmetrically along the anode body 13 to clamp the anode body 13 and are fixed with the positioning column 124 through bolts and nuts, thereby realizing reliable fixation of the anode body 13.

[0050] As shown, Figures 1 to 11 The anode bed system closed hole construction method of the present application is described by taking a deep well anode bed as an example, and specifically includes the following steps:

[0051] ① Install the support frame 11: The support frame 11 includes four vertical columns 103, the two ends of the vertical column 103 are respectively welded through the upper cover plate 121, the lower cover plate 122 and the top cover plate 101, the bottom cover plate 102, specifically, the upper cover plate 121 and the lower cover plate 122 are each uniformly distributed with four light holes 1031 along the circumference, and the light holes 1031 on the upper cover plate 121 and the lower cover plate 122 are symmetrically arranged, for the four vertical columns 103 to pass through, so that the four vertical columns 103 are uniformly distributed along the circumference of the upper cover plate 121. The lifting lug 104 is arranged on the top cover plate 101 and is threadedly connected or welded to the top cover plate 101. This step needs to do corrosion protection treatment on the welding port and the surface of the whole support frame 11, and preferably apply epoxy anticorrosive paint; the materials of the top cover plate 101, the bottom cover plate 102, the vertical column 103 and the lifting lug 104 are all made of 316L stainless steel material; the support frame 11 ensures the structural integrity and reliability of the anode assembly 1 during production, storage, transportation and on-site installation of the anode assembly 1.

[0052] ②Install the corrosion-resistant frame 12: push the upper cover plate 121 and the lower cover plate 122 to the two ends to be close to the top cover plate 101 and the bottom cover plate 102 respectively, the upper cover plate 121, the lower cover plate 122, the top cover plate 101 and the bottom cover plate 102 are coaxially arranged and have the same diameter, the top cover plate 101 is arranged with six large light holes 1012 at intervals in the circumferential direction, the bottom cover plate 102 is symmetrically provided with six large light holes 1012, the upper cover plate 121 and the lower cover plate 122 are provided with small light holes 1211 coaxial with the above-mentioned large light holes 1012, the two ends of the support column 123 are provided with threaded holes, the bolt 125 passes through the large light hole 1012, the small light hole 1211 and the threaded hole to cooperate with the threaded hole to fix the support column 123 between the upper cover plate 121 and the lower cover plate 122, in the embodiment, the support column 123 is provided with four and has the same fixing mode, the two positioning columns 124 are also fixed in the same way as the support column 123 between the upper cover plate 121 and the lower cover plate 122, the two positioning columns 124 are arranged in the middle, and the four support columns 123 are arranged on both sides of the positioning column 124 in two groups; the corrosion-resistant frame 12 ensures the structural integrity and performance reliability of the anode assembly 1 in the service life. The combination of the top cover plate 101 and the upper cover plate 121 is provided with four through holes 1011, which have the functions of anode lead channel and facilitate the circulation of medium on the anode assembly 1 and the medium in the anode assembly 1, auxiliary exhaust, ground water infiltration and the like.

[0053] ③Install the anode body 13: in the embodiment, three coaxial and butt-jointed anode bodies 13 are provided, the anode body 13 is coaxially arranged with the upper cover plate 121 and the diameter of a single anode body 13 is 150mm-300mm and the length is 0.5m-2m. Each anode body 13 is fixed by bolt-nut, two groups of clamps 131 and positioning columns 124, specifically, the middle section of the clamp 131 is an arc shape matched with the outer shape of the anode body 13, the two ends are flat plates, the arc-shaped part and the flat plate part are provided with through holes, the arc-shaped part can semi-wrap the anode body 13, two groups of clamps 131 are arranged symmetrically along the radial direction of the anode body 13 to clamp the anode body 13 tightly, the positioning column 124 is provided with a through hole, the flat plate part of the clamp 131 is fixed on the positioning column 124 by bolt-nut, preferably, the material of the bolt-nut and the clamp 131 is polytetrafluoroethylene;

[0054] (4) Install anode lead 2, exhaust pipe 14: Weld 2 to 3 anode leads 2 at the middle of each anode body 13 length direction, evenly distributed along its circumference, and the welding point and the end of the insulation layer are covered with asphalt for corrosion protection and sealing. Each anode lead 2 is marked or identified by the color of the insulation layer, and corresponds to the installation position of the connected anode body on the anode assembly 1. The material of the anode lead 2 is silver wire, the diameter is >= 3mm, and the insulation layer is polytetrafluoroethylene. After the anode assembly 1 is installed in the deep well, it may settle. In order to avoid the tension caused by the settlement of the anode assembly 1 on the welding point of the anode lead 2, especially the anode lead 2, which leads to functional failure, each anode lead 2 of the present application is first routed to the vicinity of the upper cover plate 121, then along the wire protection pipe 21 to the vicinity of the lower cover plate 122, and then led out through the wire protection pipe 21. The preferred material of the wire protection pipe 21 of the present application is polytetrafluoroethylene. The winding method of the anode lead 2 from the welding point to the pipe opening of the wire protection pipe 21 can also be a zigzag winding method similar to a mountain pass.

[0055] Gas may be naturally produced in the anode bed, or generated by electrolysis. The anode body 13 of the present application is designed with two exhaust pipes 14 on both sides to prevent gas blockage. The inner diameter of the exhaust pipe 14 is preferably >= 50mm. The exhaust pipe 14 is composed of an assembly inner section 141 and an assembly outer section 142. During on-site construction, the assembly inner section 141 and the assembly outer section 142 are connected by a casing 143 or bonded together by heat fusion at the wellhead 6. The assembly inner section 141 is arrayed with exhaust holes 144 and has a plugging head at the bottom. The assembly inner section 141 of the exhaust pipe 14 is covered with corrosion-resistant cloth, and the hole diameter or the spacing between the wire weaves on the cloth is 150um-230um, which allows gas to pass through and reduces the size of the entering object as much as possible to prevent the exhaust pipe 14 from being blocked by too many entering objects, resulting in exhaust failure. The corrosion-resistant cloth is fixed by a binding tape. The exhaust pipe 14, the casing 143, the plugging head, the corrosion-resistant cloth, and the binding tape are all made of polytetrafluoroethylene material. The exhaust pipe 14 is installed with a protective net at the end near the wellhead 6 to prevent insects or foreign objects from entering, and a U-shaped downward pipe 145 is also installed. The exhaust pipe 14 is not close to the ground terminal box 3 or the rectifier.

[0056] (5) Drilling: Under the condition that the on-site geological conditions are met, the method of replacing mud with circulating water is used to drill the well. The main consideration for the target well depth is that after installation, the anode assembly 1 is below the water layer, there are filler layers above and below the anode assembly 1, and the thickness of the filler layers is preferably >= 1m. The gravel layer between the wellhead 6 and the filler is preferably >= 1m thick.

[0057] (6) Pump out the mud in the well and put it into the filler below the anode assembly 1: The filler should be pre-soaked with water or mixed with water to form a slurry, then put the soaked filler or pump the slurry into the well. The target thickness of the filler in the well is 1m-1.5m, ensuring that the filler is densely packed.

[0058] VII. Hoisting and placing the anode assembly 1: The crane uses the lifting lugs 104 of the anode assembly 1 to deliver the anode assembly 1 into the wellhead 6, and connects or heat-welds the inner section 141 and the outer section 142 of the assembly together at the wellhead 6, and straightens the anode lead 2 and the lead pipe 21, and then the crane places the anode assembly 1 into the well, and the structure of the anode assembly 1 has the function of a centralizer.

[0059] VIII. Placing carbonaceous fillers around the anode body 13 and on the top of the anode assembly 1: The fillers are preferably mixed with water into a slurry in advance, and then the slurry is pumped into the well, and the target thickness of the fillers in the well is more than 1 m to 1.5 m above the top surface of the anode assembly 1, to ensure that the fillers are densely filled around the anode body 13 and on the top of the anode assembly 1, and then gravel is placed after the fillers are settled, and the fillers are filled to the ground.

[0060] IX. Cementing the well with the brick or the cement protection pipe 4: The cement protection pipe 4 is inserted into the gravel layer at the wellhead 6, and the exhaust pipe 14 and the anode lead 2 both extend out through the cement protection pipe 4, and the cement protection pipe 4 is provided to protect the exhaust pipe 14 and the anode lead 2 from being damaged by human beings, and in addition, a cap 41 is provided at the pipe opening of the cement protection pipe 4, and the cap 41 has a vent hole 411 to prevent gas accumulation, and then a permanent anode bed marker pile is provided at the deep well anode bed.

[0061] X. Installing the ground terminal box 3 and the cable: The ground terminal box 3 is installed and the anode lead 2 is connected according to the design requirements, the protection level of the box body of the ground terminal box 3 is ≧IP66 and meets the requirements of fireproofing and safety specifications, and the metal surface coating of the ground terminal box 3 is preferably epoxy anticorrosive paint, the section of the anode lead 2 with the lead pipe 21 from the top end of the cement protection pipe 4 to the ground terminal box 3 is provided with a hot-dipped galvanized metal lead pipe and is buried underground to improve the mechanical strength, and the surface of the metal lead pipe is coated with epoxy anticorrosive paint. The preferred material of the busbar of the anode lead 2 at the inlet of the ground terminal box 3 and the anode cable 5 at the outlet is silver plate, and the preferred material of the fasteners such as bolts, nuts and gaskets of the terminal is silver-plated stainless steel. There is an insulating support between the busbar and the shell of the ground terminal box 3. In order to prevent capillary action between the cable insulation layers, the cable inlet and outlet of the box body of the ground terminal box 3 is insulated and sealed to prevent corrosive media from entering the ground terminal box 3, and the anode lead 2 has no joint between the welding point and the ground terminal box 3.

[0062] The above-described embodiments are merely preferred embodiments of the present application, and are not intended to limit the scope of the present application, and various modifications and improvements to the technical solutions of the present application made by those skilled in the art without departing from the design spirit of the present application shall fall within the protection scope of the present application defined by the claims.

Claims

1. An anode ground bed system for heavily corrosive environments, comprising anode leads (2) and a ground junction box (3), characterized in that, It also includes an anode assembly (1), which includes a support frame (11), a corrosion-resistant frame (12), and at least two coaxially connected anode bodies (13) fixed between the two. The anode bodies (13) are platinum-titanium composite tubes or platinum-niobium composite tubes, and the anode leads (2) are silver wires. The support frame (11) includes a top cover plate (101), a bottom cover plate (102), and four columns (103) fixedly supported between the two. The corrosion-resistant frame (12) includes an upper cover plate (121), a lower cover plate (122), support columns (123), and positioning columns (124). The support columns (123) and positioning columns (124) are fixedly connected to the upper cover plate (121) and the lower cover plate (122) by bolts (125). The upper cover plate (121), lower cover plate (122), top cover plate (101), and bottom cover plate (102) are arranged coaxially and have the same diameter; The anode body (13) is fixedly connected to the positioning post (124). Two to three anode leads (2) are evenly welded around the center of the anode body (13). Four through holes (1011) are provided on the combination of the top cover plate (101) and the upper cover plate (121). Two of the through holes (1011) serve as the threading channels for the anode leads (2). After the anode leads (2) are led out from the welding point of the anode body (13), they first go around to the vicinity of the upper cover plate (121), then go around to the vicinity of the lower cover plate (122) along the wire protection tube (21), and then go out from the through hole (1011) through the wire protection tube (21) and connect to the ground junction box (3).

2. The anodic ground bed system for heavily corrosive environments according to claim 1, characterized in that, The anode assembly (1) also includes several exhaust pipes (14), each exhaust pipe (14) comprising an inner section (141) and an outer section (142) connected by a sleeve (143) or by hot-melt bonding. The inner section (141) of the assembly is provided with an array of exhaust holes (144) and a sealing head at the bottom.

3. The anodic ground bed system for heavily corrosive environments according to claim 2, characterized in that, The inner section (141) of the exhaust pipe (14) is covered with a corrosion-resistant cloth with a pore size or weave spacing of 150um to 230um. The corrosion-resistant cloth is fixed by a strapping strap. The exhaust pipe (14), sleeve (143), sealing head, corrosion-resistant cloth, and strapping strap are all made of polytetrafluoroethylene material.

4. The anodic ground bed system for heavily corrosive environments according to claim 3, characterized in that, The exhaust pipe (14) is equipped with a protective net to prevent insects or foreign objects from entering at the end near the wellhead (6) and is also fitted with a U-shaped downward bend pipe (145).

5. The anodic ground bed system for heavily corrosive environments according to claim 4, characterized in that, It also includes bolts and nuts made of polytetrafluoroethylene and two sets of clamps (131). The middle section of the clamp (131) is an arc shape adapted to the shape of the anode body (13), and the two ends are flat plates. Through holes are provided on the arc part, the flat part and the positioning post (124). Two sets of clamps (131) are symmetrically arranged along the radial direction of the anode body (13) to clamp the anode body (13) and fix it to the positioning post (124) with bolts and nuts.

6. The anodic ground bed system for heavily corrosive environments according to claim 5, characterized in that, The top cover plate (101) is threaded or welded with lifting lugs (104).

7. The anodic ground bed system for heavily corrosive environments according to claim 6, characterized in that, The top cover plate (101), bottom cover plate (102), column (103), and lifting lug (104) are all made of 316L stainless steel, and the surface of the support frame (11) is coated with epoxy anti-corrosion paint.

8. The anodic ground bed system for heavily corrosive environments according to claim 7, characterized in that, The upper cover plate (121), lower cover plate (122), positioning post (124) and bolt (125) are made of polytetrafluoroethylene material, and the support post (123) is a polytetrafluoroethylene post with a carbon fiber tube inside.

9. The closed-hole construction method for an anodic bed system for heavily corrosive environments according to any one of claims 1 to 8, characterized in that, Includes the following steps: ① Install the support frame (11): The two ends of the four columns (103) that are evenly distributed around the circumference of the upper cover plate (121) pass through the upper cover plate (121) and the lower cover plate (122) respectively, and are then welded to the top cover plate (101) and the bottom cover plate (102); ② Install the corrosion-resistant frame (12): Push the upper cover plate (121) and lower cover plate (122) to their ends and press them against the top cover plate (101) and bottom cover plate (102) respectively, and fix the support column (123) and positioning column (124) between the upper cover plate (121) and lower cover plate (122) with bolts (125); ③ Install anode bodies (13): Connect the three anode bodies (13) coaxially and fix each anode body (13) to the positioning column (124) with bolts, nuts, and two sets of clamps (131); ④ Install anode leads (2) and exhaust pipes (14): Weld 2 to 3 anode leads (2) evenly around the circumference at the middle position of the length of each anode body (13). Cover the weld points and the insulation layer ends of the anode leads (2) with asphalt for corrosion protection and sealing. The combination of the top cover plate (101) and the upper cover plate (121) is provided with 4 through holes (1011). Two of the through holes (1011) serve as the wire passages for the anode leads (2). After the anode leads (2) are led out from the weld points of the anode body (13), they first go around to the vicinity of the upper cover plate (121), then go around to the vicinity of the lower cover plate (122) along the wire protection tube (21), and then lead out from the through holes (1011) through the wire protection tube (21). Two exhaust pipes (14) are arranged on both sides of the anode body (13). Install the inner section (141) of the combination of exhaust pipes (14) and corrosion-resistant cloth. ⑤ Drilling: The circulating water displacement mud method is used for drilling. After installation, the anode assembly (1) is below the water layer and there are carbonaceous filler layers around and above and below the anode body (13). There is a gravel layer between the wellhead (6) and the filler. ⑥ Extract the mud from the well and put in the carbonaceous packing material under the anode assembly (1): The packing material is pre-wetted with water or mixed with water to form a slurry, and then the wetted packing material is put in or the slurry is pumped into the well. The target thickness of the packing material in the well is 1m to 1.5m to ensure that the packing material is filled tightly. ⑦ Hoisting and placing the anode assembly (1): The crane uses the lifting lug (104) of the anode assembly (1) to send the anode assembly (1) into the wellhead (6). At the wellhead (6), the inner section (141) and outer section (142) of the exhaust pipe (14) are joined together by the sleeve (143) or by hot-melt bonding. The anode lead wire (2) and the protective pipe (21) leading out from the anode assembly (1) are straightened. The crane then sends the anode assembly (1) into the well. ⑧ Place carbonaceous filler around the anode body (13) and on top of the anode assembly (1): The filler is premixed with water to form a slurry, and then the slurry is pumped into the well. The target thickness of the filler in the well exceeds the top surface of the anode assembly (1) by 1m to 1.5m. Ensure that the filler is densely packed around the anode body (13) and on top of the anode assembly (1). After the filler settles, gravel is placed and filled to the ground. ⑨ Cementing with brick or cement protective pipe (4): Insert cement protective pipe (4) into the gravel layer at the wellhead (6), and extend the exhaust pipe (14) and anode lead (2) through the cement protective pipe (4) outward. Set permanent ground bed marker stakes at the anode ground bed of the deep well. ⑩ Ground junction box (3) and cable installation: A section of the anode lead (2) from the top of the cement protective pipe (4) to the ground junction box (3) is reinforced with a hot-dip galvanized metal conduit and buried underground. The surface of the ground junction box (3) and the metal conduit is coated with epoxy anti-corrosion paint. The busbar of the anode lead (2) at the inlet of the ground junction box (3) and the anode cable (5) at the outlet is silver plate. The bolts, nuts and washers of the terminals on the busbar are silver plated. An insulating bracket is set between the busbar and the housing of the ground junction box (3) to provide insulation and sealing for the cable inlet and outlet of the ground junction box (3).

10. The construction method of the anodic bed system for heavily corrosive environments according to claim 9, characterized in that, In step ②, two positioning columns (124) are arranged in the center, and four support columns (123) are placed in pairs on both sides of the positioning columns (124). The anode body (13) is located between the two positioning columns (124).

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