Electrochemical protection device for inner wall of oil-water container

Abstract

The invention relates to an electrochemical protection device for the inner wall of an oil-water container, which comprises an auxiliary cathode, the auxiliary cathode is connected with an auxiliary cathode grounding body through a grounding wire, the main body structure of the auxiliary cathode is an auxiliary cathode alloy tube body, the outer side of the auxiliary cathode alloy tube body is provided with two holes, and the two holes are communicated with the auxiliary cathode grounding body. A first base and a second base are welded to the outer sides of the two holes correspondingly, the interiors of the first base and the second base are connected with a threaded cable sealing head and a threaded reference electrode through threads correspondingly, and a reference cable penetrates through the middle of the threaded cable sealing head in a sealed and inserted mode. According to the equipment provided by the embodiment of the invention, the continuous electrons provided by the direct-current power supply balance the potential difference of the cathode and the anode of the electrochemical corrosion primary battery generated by the damaged opening of the anticorrosive layer in the container in the saline electrolyte environment at the bottom in the metal oil-water container, so that the electrochemical protection effect on the inner wall of the metal oil-water container is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of oil and gas field ground engineering corrosion and protection, and in particular to an electrochemical protection device for the inner wall of an oil and water container. Background Art

[0002] Patent No. CN104328440B discloses an impressed current cathodic protection device for the inner wall of a container or a pipeline. Comparison: The device to which this patent belongs opens a hole on the surface of a container or a pipeline, installs a base, an insulating device and an auxiliary anode, the auxiliary anode contacts the water medium inside the container and is insulated from the inner wall of the container or the pipeline, the auxiliary anode is connected to the positive pole of a DC power supply, and the metal part of the container or pipeline is connected to the negative pole of a DC power supply, thereby forming an impressed current cathodic protection system for the inner wall of the pipeline or container. Disadvantages: It can only be applied to the protection of the inner wall of a pure water container; there are safety hazards when it is applied to the protection of the inner wall of an oil and water container in an oil field scenario. The reason is: in oil field production, oil and gas may enter the container or pipeline of the device described in the above patent in the oil and water container or pipeline, and it is difficult to avoid mixing with air in the surface process of the oil and gas field. In this unexpected situation, there are safety hazards of explosion using the above patented device and method. Therefore, we propose an electrochemical protection device for the inner wall of an oil and water container. Summary of the invention

[0003] The present application provides an electrochemical protection device for the inner wall of an oil-water container to solve the problem that the prior art patent number CN104328440B discloses a container and pipeline inner wall impressed current cathodic protection device which can only be applied to the inner wall protection of a pure water container and there are potential safety hazards when applied to the inner wall protection of an oil-water container in an oil field scenario.

[0004] In order to solve the above technical problems or at least partially solve the above technical problems, the present application provides an electrochemical protection device for the inner wall of an oil-water container, comprising:

[0005] An auxiliary cathode, wherein the auxiliary cathode is connected to an auxiliary cathode grounding body through a grounding wire, the main structure of the auxiliary cathode is an auxiliary cathode alloy tube body, two holes are opened on the outside of the auxiliary cathode alloy tube body, and a first base and a second base are welded on the outside of the two holes respectively, the insides of the first base and the second base are both connected to a threaded cable sealing head and a threaded reference electrode through threads, and a reference cable is sealed and plugged through the middle of the threaded cable sealing head, and the reference cable is welded to the outer wall of the hole surrounded by the first base;

[0006] A direct current power supply, wherein the direct current power supply is connected to the side wall of the metal oil-water container and the auxiliary anode through a wire;

[0007] The auxiliary cathode is sealed and connected to a bottom water discharge pipeline, and the bottom water discharge pipeline is fixedly plugged into the lower part of the side wall of the metal oil-water container.

[0008] Optionally, a first flange and a second flange are welded to both ends of the auxiliary cathode alloy tube body, respectively, and the first flange and the second flange are insulated and connected to the bottom water discharge pipeline.

[0009] Optionally, a sealing plug with a hole is provided at the inner lower portion of the first base, and the reference cable is inserted through the middle portion of the sealing plug with a hole.

[0010] Optionally, the threaded reference electrode is equipped with a polyfluorocarbon sealing gasket and is threadedly connected to the second base.

[0011] Optionally, a plurality of auxiliary anode and auxiliary cathode grounding bodies are provided, and the auxiliary anode and auxiliary cathode grounding bodies are deeply buried underground, and the distance between the auxiliary anode and auxiliary cathode grounding bodies is not less than 1 m.

[0012] Optionally, the outer surface of the auxiliary cathode is coated with insulating anti-corrosion material.

[0013] Optionally, the metal oil-water container is connected to an intelligent drainage controller via a wire, and the intelligent drainage controller is connected to a lightning protection grounding body via a ground wire.

[0014] Optionally, the metal oil-water container, the bottom water discharge pipeline, the auxiliary cathode, the auxiliary cathode grounding body, the auxiliary anode and the DC power supply form a closed loop.

[0015] Optionally, the outer side of the auxiliary cathode alloy tube body is connected to the auxiliary cathode grounding body through an auxiliary cathode grounding body connecting cable.

[0016] Optionally, a container steel base is fixedly connected to the left and right sides of the lower end of the metal oil-water container, and the container steel base is fixedly placed on the container cement foundation.

[0017] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0018] The device provided by the embodiment of the present application, after the DC power supply is started, the electrons flow to the metal body of the metal oil and water container through the negative line of the DC power supply, and then flow into the conductive salt water medium in the container through the damaged port of the anti-corrosion layer of the anti-corrosion coating on the inner surface of the metal oil and water container. Under the action of the conductive ions in the conductive salt water in the container, the electrons are conducted to the inner surface of the auxiliary cathode alloy tube body, and then the electrons flow into the soil through the auxiliary cathode grounding body through the auxiliary cathode alloy tube body connected to the auxiliary cathode grounding body connection cable under the action of the external electric field, and then flow into the auxiliary anode, and flow back to the DC power supply through the positive line of the DC power supply. The continuous electrons provided by the DC power supply balance the potential difference between the positive and negative electrodes of the electrochemical corrosion primary cell generated by the damaged port of the anti-corrosion layer in the bottom salt water electrolyte environment of the metal oil and water container, thereby playing an electrochemical protection role for the inner wall of the metal oil and water container, and the lightning protection grounding body of the metal oil and water container is connected in series with the intelligent drainage controller through a wire. When encountering high voltage hazards during thunderstorm weather or other electrical system grounding faults, the intelligent drainage controller is intelligently turned on to eliminate lightning strikes or other abnormal overvoltage hazards. In other states, the intelligent drain controller is in the off state to ensure that the system electrochemical protection current passes through the conductive brine in the container and flows back to the DC power supply through the auxiliary cathode. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0021] Figure 1 This is an overall structural diagram of an electrochemical protection device for the inner wall of an oil-water container;

[0022] Figure 2 This is a diagram of the auxiliary cathode structure of an electrochemical protection device for the inner wall of an oil-water container.

[0023] In the figure: 1. Metal oil and water container; 101. Damaged opening of the anti-corrosion layer inside the container; 102. Conductive brine inside the container; 103. Steel base of the container; 104. Cement foundation of the container; 105. Bottom water discharge pipeline; 2. Auxiliary cathode; 201. Auxiliary cathode grounding body; 202. Auxiliary cathode alloy pipe body; 203. Auxiliary cathode grounding body connecting cable; 204. First flange; 205. Second flange; 206. First base; 207. Sealing plug with holes; 208. Threaded cable sealing head; 209. Reference cable; 210. Second base; 211. Threaded reference electrode; 3. Intelligent drainage controller; 301. Lightning protection grounding body; 4. DC power supply; 401. Auxiliary anode. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0025] Various embodiments of the present application may exist in the form of a range. It should be understood that the description in the form of a range is only for convenience and simplicity and should not be understood as a hard limit to the scope of the present application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single values ​​within the range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which are applicable regardless of the range. In addition, whenever a numerical range is indicated in the present application, it is meant to include any quoted numbers (fractions or integers) within the indicated range. Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present application, etc., can be purchased from the market or can be prepared by existing methods.

[0026] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the present application, the terms "include", "comprise", etc. refer to "including but not limited to". In the present application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In the present application, "and / or" describes the association relationship of the associated objects, indicating that three relationships may exist, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. Wherein A, B can be singular or plural. In the present application, "at least one" refers to one or more, and "plural" refers to two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of singular items or plural items. For example, "at least one of a, b, or c" or "at least one of a, b and c" can both mean: a, b, c, ab, i.e. a and b, ac, bc or abc, where a, b, c can be single or plural, respectively.

[0027] like Figure 1-2 As shown, the embodiment of the present application provides an electrochemical protection device for the inner wall of an oil-water container, comprising:

[0028] Auxiliary cathode 2, the auxiliary cathode 2 is connected to the auxiliary cathode grounding body 201 through a grounding wire, the main structure of the auxiliary cathode 2 is an auxiliary cathode alloy tube body 202, the outer side of the auxiliary cathode alloy tube body 202 is opened with two holes, and the outer sides of the two holes are respectively welded with a first base 206 and a second base 210, the insides of the first base 206 and the second base 210 are both connected with a threaded cable sealing head 208 and a threaded reference electrode 211 through threads, and the middle part of the threaded cable sealing head 208 passes through a sealed plug-in reference cable 209, and the reference cable 209 is welded to the outer side wall of the hole surrounded by the first base 206;

[0029] A DC power supply 4, wherein the DC power supply 4 is connected to the side wall of the metal oil-water container 1 and the auxiliary anode 401 through a wire;

[0030] The auxiliary cathode 2 is sealed and connected to the bottom water discharge pipeline 105 , and the bottom water discharge pipeline 105 is fixedly plugged into the lower part of the side wall of the metal oil-water container 1 .

[0031] Specifically: the DC power supply 4 is installed in the power distribution room of the station or a separate cathode protection room. The DC power supply 4 is a 5-bit high-precision DC power supply with interactive information intelligent control. A constant potential instrument or other intelligent control type DC power supply can also be used. The basic requirement is to collect the corrosion potential of the inner surface of the auxiliary cathode tube and control it within the expected protection potential value range, so as to implement automatic control protection;

[0032] The auxiliary cathode tube body 202 is recommended to be made of the same material as the container connection pipeline, and can also be made of alloy steel to improve corrosion resistance;

[0033] like Figure 1 As shown, a first flange 204 and a second flange 205 are respectively welded at both ends of the auxiliary cathode alloy tube body 202 , and the first flange 204 and the second flange 205 are insulated and connected to the bottom water discharge pipeline 105 .

[0034] Specifically, the intermediate insulating member used for the insulation between the first flange 204 and the second flange 205 of the auxiliary cathode 2 is preferably made of an insulating material with a certain elasticity that is not prone to aging and cracking, such as polytetrafluoroethylene.

[0035] like Figure 1 As shown: a sealing plug 207 with a hole is provided at the lower inner part of the first base 206, and the reference cable 209 is inserted through the middle of the sealing plug 207 with a hole.

[0036] Specifically, the perforated sealing plug 207 plays a sealing role.

[0037] like Figure 1 As shown: the threaded reference electrode 211 is equipped with a polyfluorocarbon sealing gasket and is threadedly connected to the second base.

[0038] Specifically: install PTFE sealing gasket to increase its sealing performance.

[0039] like Figure 1 As shown: the auxiliary anode 401 and the auxiliary cathode grounding body 201 are both provided in plurality, and the auxiliary anode 401 and the auxiliary cathode grounding body 201 are both deeply buried underground, and the distance between the auxiliary anode 401 and the auxiliary cathode grounding body 201 is not less than 1m.

[0040] Specifically: the auxiliary cathode grounding body 201 and the auxiliary anode grounding body 401 are recommended to be buried 3m underground, and the distance between the auxiliary anode 401 and the auxiliary cathode 2 is not less than 1m; the recommended installation position is not less than 30m away from the metal oil and water container 1; the total grounding resistance of multiple auxiliary cathode grounding bodies 201 and auxiliary anode grounding bodies 401 after being combined into one cable is tested separately to ensure that the grounding resistance is not greater than 1Ω. The auxiliary cathode 2 is connected to the auxiliary cathode grounding body 201 buried in the soil through the auxiliary cathode grounding body 203 connecting cable;

[0041] The auxiliary anode 401 can be made of high silicon cast iron or titanium-based metal oxide.

[0042] The auxiliary cathode grounding body 201 can be made of alloy steel to improve corrosion resistance, or it can be made of the same material as the container connecting pipeline, or a hot-dip galvanized grounding electrode.

[0043] like Figure 1 As shown: the outer surface of the auxiliary cathode 2 is coated with insulating anti-corrosion material.

[0044] Specifically, the insulating anti-corrosion material is used to protect the outer surface of the auxiliary cathode 2 from rain and air corrosion.

[0045] like Figure 1 As shown: the metal oil-water container 1 is connected to the intelligent drainage controller 3 through a wire, and the intelligent drainage controller 3 is connected to the lightning protection grounding body 301 through a ground wire.

[0046] Specifically: when encountering high voltage hazards due to thunderstorms or other electrical system grounding faults, the intelligent current discharge controller 3 is intelligently turned on to eliminate lightning strikes or other abnormal overvoltage hazards.

[0047] like Figure 1 As shown: the metal oil-water container 1, the bottom water discharge pipeline 105, the auxiliary cathode 2, the auxiliary cathode grounding body 201, the auxiliary anode 401 and the DC power supply 4 form a closed loop.

[0048] Specifically, the continuous electrons provided by the DC power supply 4 balance the potential difference between the positive and negative electrodes of the electrochemical corrosion primary cell generated by the damaged opening 101 of the anti-corrosion layer in the container in the salt water electrolyte environment at the bottom of the metal oil-water container 1, thereby playing an electrochemical protective role on the inner wall of the metal oil-water container 1.

[0049] like Figure 1 As shown: the outer side of the auxiliary cathode alloy tube body 202 is connected to the auxiliary cathode grounding body 201 through the auxiliary cathode grounding body connecting cable 203.

[0050] Specifically, the cathode grounding body connecting cable 203 plays a role in grounding and conducting electricity.

[0051] like Figure 1 As shown: the left and right sides of the lower end of the metal oil-water container 1 are fixedly connected with a container steel base 103 , and the container steel base 103 is fixedly placed on a container cement foundation 104 .

[0052] When the equipment is in use, the electrochemical electron flow path diagram of the inner wall of the metal oil-water container 1 and the related devices are as follows Figure 1After the connection and installation, the DC power supply 4 is started, and the electrons flow to the metal body of the metal oil-water container 1 through the negative line of the DC power supply 4, and then flow into the conductive salt water 102 medium in the container through the damaged port 101 of the anti-corrosion layer in the container of the anti-corrosion coating on the inner surface of the metal oil-water container 1. Under the action of the conductive ions in the conductive salt water 102 in the container, the electrons are conducted to the inner surface of the auxiliary cathode alloy tube body 202, and then the electrons flow into the soil through the auxiliary cathode grounding body connecting cable 203 through the auxiliary cathode grounding body 201 under the action of the external electric field, and then flow into the auxiliary anode 401, and flow back to the DC power supply 4 through the positive line of the DC power supply. The continuous electrons provided by the DC power supply 4 balance the potential difference between the positive and negative electrodes of the electrochemical corrosion primary cell generated by the damaged port 101 of the anti-corrosion layer in the bottom salt water electrolyte environment of the metal oil-water container 1, thereby playing an electrochemical protection role for the inner wall of the metal oil-water container 1;

[0053] The auxiliary anode 401 connected to the positive electrode of the DC power supply 4 is buried in the soil, away from the oil and gas danger source, avoiding the explosion safety hazards existing in the prior art;

[0054] There are two current steering methods:

[0055] 1. If Figure 1 The container cement foundation 104 is a reinforced concrete base, and the cement-to-ground resistance is 200 to 300 ohms. Through the arrangement of the auxiliary anode 401 and the auxiliary cathode grounding body 201, the system grounding resistance can be less than 1 ohm, thereby guiding the system current to flow through the conductive brine 102 in the container as much as possible.

[0056] 2. If Figure 1 The auxiliary cathode grounding body 201 is connected to the bottom water discharge pipeline 105 of the metal oil-water container 1 through an insulating flange, thereby preventing the protection current from directly passing through the metal pipe wall of the metal oil-water container 1 to form a loop.

[0057] Overvoltage and current path control method: Figure 1 The lightning protection grounding body 301 of the metal oil-water container 1 is connected in series with the intelligent current discharge controller 3 through a wire. When encountering high voltage hazards due to thunderstorm weather or other electrical system grounding faults, the intelligent current discharge controller 3 is intelligently turned on to eliminate lightning strikes or other abnormal overvoltage hazards. In other states, the intelligent current discharge controller 3 is in the off state to ensure that the system electrochemical protection current passes through the conductive salt water 102 in the container and flows back to the DC power supply 4 through the auxiliary cathode 2.

[0058] The above is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. It will be apparent to those skilled in the art that various modifications to these embodiments are possible, and the general principles defined in the present application can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown in the present application, but will conform to the widest scope consistent with the principles and novel features applied for by the present application.

Claims

1. An electrochemical protection device for the inner wall of an oil-water container, characterized in that: include: An auxiliary cathode (2), wherein the auxiliary cathode (2) is connected to an auxiliary cathode grounding body (201) via a grounding wire, the main structure of the auxiliary cathode (2) is an auxiliary cathode alloy tube body (202), two holes are opened on the outside of the auxiliary cathode alloy tube body (202), and a first base (206) and a second base (210) are respectively welded to the outsides of the two holes, the insides of the first base (206) and the second base (210) are both threadedly connected to a threaded cable sealing head (208) and a threaded reference electrode (211), and a sealed plug-in reference cable (209) passes through the middle of the threaded cable sealing head (208), and the reference cable (209) is welded to the outer wall of the hole surrounded by the first base (206); A direct current power source (4), wherein the direct current power source (4) is connected to a side wall of the metal oil-water container (1) and an auxiliary anode (401) via a wire; The auxiliary cathode (2) is sealed and connected to a bottom water discharge pipeline (105), and the bottom water discharge pipeline (105) is fixedly plugged into the lower part of the side wall of the metal oil-water container (1).

2. The electrochemical protection device for the inner wall of an oil-water container according to claim 1, characterized in that: A first flange (204) and a second flange (205) are respectively welded to both ends of the auxiliary cathode alloy tube body (202); the first flange (204) and the second flange (205) are insulated and connected to the bottom water discharge pipeline (105).

3. The electrochemical protection device for the inner wall of an oil-water container according to claim 1, characterized in that: A sealing plug (207) with a hole is provided at the lower inner portion of the first base (206), and the reference cable (209) is inserted through the middle portion of the sealing plug (207).

4. The electrochemical protection device for the inner wall of an oil-water container according to claim 1, characterized in that: The threaded reference electrode (211) is equipped with a polyfluoroethylene sealing gasket and is threadedly connected to the second base.

5. The electrochemical protection device for the inner wall of an oil-water container according to claim 1, characterized in that: The auxiliary anode (401) and the auxiliary cathode grounding body (201) are both provided in plurality, the auxiliary anode (401) and the auxiliary cathode grounding body (201) are both deeply buried underground, and the distance between the auxiliary anode (401) and the auxiliary cathode grounding body (201) is not less than 1 m.

6. The electrochemical protection device for the inner wall of an oil-water container according to claim 1, characterized in that: The outer surface of the auxiliary cathode (2) is coated with an insulating anti-corrosion material.

7. The electrochemical protection device for the inner wall of an oil-water container according to claim 1, characterized in that: The metal oil-water container (1) is connected to an intelligent drainage controller (3) via a wire, and the intelligent drainage controller (3) is connected to a lightning protection grounding body (301) via a ground wire.

8. The electrochemical protection device for the inner wall of an oil-water container according to claim 1, characterized in that: The metal oil-water container (1), the bottom water discharge pipeline (105), the auxiliary cathode (2), the auxiliary cathode grounding body (201), the auxiliary anode (401) and the DC power supply (4) form a closed loop.

9. The electrochemical protection device for the inner wall of an oil-water container according to claim 1, characterized in that: The outside of the auxiliary cathode alloy tube body (202) is connected to the auxiliary cathode grounding body (201) via an auxiliary cathode grounding body connecting cable (203).

10. The electrochemical protection device for the inner wall of an oil-water container according to claim 1, characterized in that: The left and right sides of the lower end of the metal oil-water container (1) are fixedly connected with a container steel base (103), and the container steel base (103) is fixedly placed on a container cement foundation (104).

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