A cathodic protection system and method for a wax-depositing container

Abstract

The present invention provides a cathodic protection system for a wax - forming container, which includes a protected tank body, a self - peeling auxiliary anode, a reference electrode and an intelligent - controlled power supply device; the self - peeling auxiliary anode is installed on the protected tank body, and the self - peeling auxiliary anode includes an anode and a heating wire, and the heating wire is arranged on the outer periphery of the anode. The reference electrode is installed on the protected tank body; the intelligent - controlled power supply device is connected to the self - peeling auxiliary anode and the reference electrode through circuits respectively, and the intelligent - controlled power supply device is used to provide power for the self - peeling auxiliary anode and the reference electrode and control the circuit connection mode between the anode and the heating wire. The intelligent - controlled power supply device can connect the heating wire to heat the wax - forming layer on the surface of the anode to melt and peel it off. When it peels off to a certain extent, cathodic peeling is carried out again. Thus, the impressed - current cathodic protection system can be used in a wax - forming container.

Description

Technical Field

[0001] The present invention relates to the technical field of anti-corrosion protection, and particularly to a cathodic protection system and method for a wax-depositing container. Background Art

[0002] With the development of the petroleum and petrochemical refining industries, the demand for the storage of crude oil production water and chemical treatment liquids is increasing. Due to the strong corrosiveness of the production water and chemical treatment liquids, storage containers need to be provided with additional anti-corrosion measures. The most common anti-corrosion measure is cathodic protection. At present, the anti-corrosion means for wax-depositing storage tanks mainly rely on the cathodic protection method of anodes. However, due to the extremely harsh corrosion environment (high temperature, high pressure, high corrosiveness, small space, etc.), the efficiency and service life of the anodes are greatly reduced, the anodes are consumed too quickly, and the excessive and frequent replacement greatly reduces the economic performance and usage effect. Relatively speaking, the cathodic protection method with impressed current is more reliable. However, the traditional auxiliary anodes generally have the problem of wax deposition on the anode surface in the container. Once the thickness of the wax deposition layer on the auxiliary anode surface reaches a certain level, the entire impressed current cathodic protection system will completely fail, and the wax-depositing container will not be effectively protected. Summary of the Invention

[0003] In order to solve the above technical problems, the present invention provides a cathodic protection system for a wax-depositing container, which can automatically peel off the wax deposition layer on the anode surface and solves the use limitation of the impressed current system in wax-depositing containers.

[0004] The specific technical solution is as follows: A cathodic protection system for a wax-depositing container includes a tank to be protected, a self-peeling auxiliary anode, a reference electrode, and an intelligent control power supply device;

[0005] The self-peeling auxiliary anode is installed on the tank to be protected. The self-peeling auxiliary anode includes an anode and a heating wire, and the heating wire is arranged on the outer periphery of the anode.

[0006] The reference electrode is installed on the tank to be protected;

[0007] The intelligent control power supply device is connected to the self-peeling auxiliary anode and the reference electrode through circuits respectively. The intelligent control power supply device is used to provide power for the self-peeling auxiliary anode and the reference electrode and control the circuit connection mode between the anode and the heating wire.

[0008] Through the above technical solution, when wax deposition occurs on the anode surface, the intelligent control power supply device can connect the heating wire to heat the wax layer on the anode surface, causing it to melt and peel off. When the peeling reaches a certain extent, the negative electrode of the intelligent control power supply device is connected to the anode, and the positive electrode is connected to the heating wire, forming an electrolytic circuit with the intelligent control power supply device, the anode, and the heating wire, resulting in cathodic peeling of the wax layer on the anode surface. This enables the impressed current cathodic protection system to be used in a wax deposition container.

[0009] Preferably, the anode is an MMO anode or a platinum anode.

[0010] Through the above technical solution, the stability of the anode is better.

[0011] Preferably, the heating wire is a spiral molybdenum wire or a spiral nickel-chromium alloy wire.

[0012] Through the above technical solution, it has good corrosion resistance, high temperature resistance, high pressure resistance, and is easy to form, suitable for the harsh environment inside the wax deposition container.

[0013] Preferably, the reference electrode is an Ag / AgCl reference electrode.

[0014] Another aspect is a protection method for a cathodic protection system for a wax deposition container, including the following steps:

[0015] 1) Install the self-peeling auxiliary anode and the reference electrode on the protected tank body respectively, and connect them to the intelligent control power supply device through wires. The intelligent control power supply device turns on the circuit to form a cathodic protection circuit, putting the protected tank body in the impressed current cathodic protection state;

[0016] 2) When the output voltage of the intelligent control power supply device exceeds the preset value or the measured protection potential continuously remains greater than a certain value for more than t1 min, the intelligent control power supply device terminates the output of the cathodic protection circuit;

[0017] 3) The positive and negative electrodes of the intelligent control power supply device will be connected to both ends of the heating wire respectively and start to output current, causing the heating wire to generate heat. The heat generated by the heating wire heats the wax layer on the anode surface, gradually melting and peeling off the wax layer;

[0018] 4) After the heating wire has heated for t2 min, the intelligent control power supply device stops providing current to the heating wire; at the same time, the negative electrode of the intelligent control power supply device is connected to the anode, and the positive electrode is connected to the heating wire, forming a circuit to cause cathodic peeling on the surface of the anode;

[0019] 5) After the remaining wax layer has been completely peeled off, the intelligent control power supply device restarts the cathodic protection circuit, putting the protected tank body back in the impressed current cathodic protection state.

[0020] Through the above technical solution, by outputting the voltage or measuring the protection potential, the intelligent control power device can determine whether the wax layer needs to be stripped. When the limit value is exceeded, the wax layer outside the heating wire anode can be preliminarily stripped by connecting the heating wire. Then, the negative pole of the intelligent control power device is connected to the anode, and the positive pole is connected to the heating wire, so that the intelligent control power device, the anode, and the heating wire form an electrolytic circuit, causing the wax layer on the anode surface to undergo cathodic stripping. After the stripping is completed, the intelligent control power device restarts the cathodic protection circuit to continue protecting the tank body.

[0021] Preferably, in step 2, the preset value is 1.6 times the normal voltage of the cathodic protection circuit.

[0022] Through the above technical solution, the wax layer on the anode surface can be processed in a timely manner without being too frequent.

[0023] Preferably, t1 in step 2 is 1.

[0024] Through the above technical solution, it can be accurately determined whether the wax layer on the anode surface needs to be stripped.

[0025] Preferably, t2 in step 4 is 3 - 5.

[0026] Through the above technical solution, the wax layer on the anode surface can be preliminarily melted and peeled off, enabling the liquid in the tank to contact the anode, so as to better achieve cathodic stripping.

[0027] The beneficial effects of the present invention are as follows:

[0028] 1. Through the intelligent control power device, automatic switching of the cathodic protection system, heating wire heating stripping, and cathodic stripping can be achieved, solving the use limitation of the impressed current system in wax - coated containers.

[0029] 2. The spiral molybdenum wire or nickel - chromium alloy wire has good corrosion resistance, high temperature resistance, high pressure resistance, and is easy to form, suitable for the harsh environment inside the wax - coated container.

[0030] 3. A protection method for a cathodic protection system for wax - coated containers has the characteristics of simple use, high intelligence level, long service life, and excellent economic performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings. Among them:

[0032] Figure 1 It is a schematic structural diagram of the present application;

[0033] Figure 2 Schematic diagram of the self-peeling auxiliary anode structure;

[0034] 1. Protected tank body, 2. Self-peeling auxiliary anode, 21. Anode, 22. Electric heating wire, 3. Reference electrode, 4. Intelligent control power supply device. Specific implementation mode

[0035] In order to make the above objects, features and advantages of the present invention more obvious and understandable, the specific implementation modes of the present invention will be described in detail below with reference to the accompanying drawings of the specification. Many specific details are set forth in the following description in order to fully understand the present invention, but the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0036] Secondly, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure or characteristic that can be included in at least one implementation mode of the present invention. The "in one embodiment" that appears in different places in this specification does not all refer to the same embodiment, nor is it a separate or selectively exclusive embodiment from other embodiments.

[0037] Embodiment 1

[0038] As Figure 1-2 shown, a cathodic protection system for a wax-depositing container includes a protected tank body 1, a self-peeling auxiliary anode 2, a reference electrode 3 (Ag / AgCl reference electrode is used in this embodiment), and an intelligent control power supply device 4;

[0039] The self-peeling auxiliary anode 2 is installed on the protected tank body 1. The self-peeling auxiliary anode 2 includes an anode 21 (MMO anode is used in this embodiment) and an electric heating wire 22 (spiral molybdenum wire is used in this embodiment), and the MMO anode passes through the spiral molybdenum wire.

[0040] The Ag / AgCl reference electrode is installed on the protected tank body 1;

[0041] The intelligent control power supply device 4 is connected to the self-peeling auxiliary anode 2 and the Ag / AgCl reference electrode through circuits respectively. The intelligent control power supply device 4 is used to provide power for the self-peeling auxiliary anode 2 and the Ag / AgCl reference electrode and control the circuit connection mode between the MMO anode and the spiral molybdenum wire.

[0042] A protection method for a cathodic protection system for a wax-depositing container includes the following steps:

[0043] 1) The self-peeling auxiliary anode 2 and the Ag / AgCl reference electrode are respectively installed on the protected tank body 1, and are connected to the intelligent control power supply device 4 through wires. The intelligent control power supply device 4 turns on the circuit to form a cathodic protection loop, so that the protected tank body 1 is in the state of cathodic protection by current;

[0044] 2) When the output voltage of the intelligent control power supply device 4 exceeds 1.6 times the normal voltage of the cathodic protection loop or the measured protection potential continuously exceeds -0.8V for more than 1 minute, the intelligent control power supply device 4 terminates the output of the cathodic protection loop;

[0045] 3) The positive and negative poles of the intelligent control power supply device 4 are respectively connected to both ends of the spiral molybdenum wire, and start to output current, so that the spiral molybdenum wire generates heat. The heat generated by the spiral molybdenum wire heats the wax layer on the surface of the MMO anode, causing the wax layer to gradually melt and peel off;

[0046] 4) After the spiral molybdenum wire is heated for 5 minutes, the intelligent control power supply device 4 stops providing current for the spiral molybdenum wire; at the same time, the negative pole of the intelligent control power supply device 4 is connected to the MMO anode, and the positive pole is connected to the spiral molybdenum wire, and a circuit is formed, causing cathodic peeling on the surface of the MMO anode;

[0047] 5) After 10 minutes of cathodic peeling, the intelligent control power supply device 4 restarts the cathodic protection loop, so that the protected tank body continues to be in the state of cathodic protection by current.

[0048] Embodiment 2

[0049] As Figure 1-2 shown, a cathodic protection system for a wax-depositing container includes a protected tank body 1, a self-peeling auxiliary anode 2, a reference electrode 3 (a pure zinc reference electrode is used in this embodiment), and an intelligent control power supply device 4;

[0050] The self-peeling auxiliary anode 2 is installed on the protected tank body. The self-peeling auxiliary anode includes an anode 21 (a platinum anode is used in this embodiment) and a heating wire 22 (a spiral nickel-chromium alloy wire is used in this embodiment), and the platinum anode passes through the spiral nickel-chromium alloy wire.

[0051] The pure zinc reference electrode is installed on the protected tank body 1;

[0052] The intelligent control power supply device 4 is connected to the self-peeling auxiliary anode 2 and the pure zinc reference electrode through circuits respectively. The intelligent control power supply device 4 is used to provide power for the self-peeling auxiliary anode 2 and the pure zinc reference electrode and control the circuit connection mode between the platinum anode and the spiral nickel-chromium alloy wire.

[0053] A protection method for a cathodic protection system of a wax-depositing container includes the following steps:

[0054] 1) The self-peeling auxiliary anode 2 and the pure zinc reference electrode are respectively installed on the protected tank body 1, and are connected to the intelligent control power supply device 4 through wires. The intelligent control power supply device 4 is connected to the circuit to form a cathodic protection loop, so that the protected tank body 1 is in the current cathodic protection state;

[0055] 2) When the output voltage of the intelligent control power supply device 4 exceeds 1.6 times the normal voltage of the cathodic protection loop or the measured protection potential continuously exceeds 0.25V for more than 1 minute, the intelligent control power supply device 4 terminates the output of the cathodic protection loop;

[0056] 3) The positive and negative poles of the intelligent control power supply device 4 will be respectively connected to both ends of the spiral nickel-chromium alloy wire, and start to output current, so that the spiral nickel-chromium alloy wire generates heat, and the heat generated by the spiral nickel-chromium alloy wire heats the wax layer on the surface of the platinum anode to gradually melt and peel off the wax layer;

[0057] 4) After the spiral nickel-chromium alloy wire is heated for 5 minutes, the intelligent control power supply device 4 stops providing current for the spiral nickel-chromium alloy wire; at the same time, the negative pole of the intelligent control power supply device 4 is connected to the platinum anode, and the positive pole is connected to the spiral nickel-chromium alloy wire, and a loop is formed to generate cathodic peeling on the surface of the platinum anode;

[0058] 5) After 10 minutes of cathodic peeling, the intelligent control power supply device 4 restarts the cathodic protection loop to make the protected tank body continue to be in the current cathodic protection state.

[0059] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A cathodic protection system for a wax-deposited container, characterized in that: It includes a protected tank, a self-stripping auxiliary anode, a reference electrode and an intelligently controlled power supply device; The self-stripping auxiliary anode is installed on the protected tank body, and the self-stripping auxiliary anode includes an anode and a heating wire, and the heating wire is arranged on the periphery of the anode; The reference electrode is installed on the protected tank; The intelligently controlled power supply device is connected to the self-stripping auxiliary anode and the reference electrode respectively through the circuit. The intelligently controlled power supply device is used to provide power to the self-stripping auxiliary anode and the reference electrode and control the circuit connection mode between the anode and the heating wire. The intelligently controlled power supply device can connect and terminate the circuit to form a cathode protection loop. The intelligently controlled power supply device can make the heating wire heat up and terminate the heating of the heating wire. The negative pole of the intelligently controlled power supply device can be connected to the anode, and the positive pole can be connected to the heating wire to form a loop, so that cathode stripping occurs on the surface of the anode.

2. A cathodic protection system for a wax deposition container according to claim 1, characterized in that: The anode is a MMO anode or a platinum anode.

3. A cathodic protection system for a wax deposition container according to claim 1, characterized in that: The heating wire is a spiral molybdenum wire or a spiral nickel-chromium alloy wire.

4. A cathodic protection system for a wax deposition container according to claim 1, characterized in that: The reference electrode is an Ag / AgCl reference electrode or a pure zinc reference electrode.

5. A protection method for a cathodic protection system of a wax deposition container, characterized in that: A cathodic protection system for a wax deposition container according to any one of claims 1 to 4 is used, comprising the following steps: 1) The self-stripping auxiliary anode and the reference electrode are respectively installed on the protected tank body, and connected to the intelligently controlled power supply device through the line. The intelligently controlled power supply device connects the circuit to form a cathodic protection loop, so that the protected tank body is in a current cathodic protection state; 2) When the output voltage of the intelligently controlled power supply device exceeds the preset value or the measured protection potential is continuously greater than a certain value for more than t1min, the intelligently controlled power supply device terminates the output of the cathodic protection circuit; 3) The positive and negative poles of the intelligent control power supply device will be connected to the two ends of the heating wire respectively, and start to output current, so that the heating wire heats up. The heat generated by the heating wire heats the wax layer on the surface of the anode, causing the wax layer to gradually melt and peel off; 4) After the heating wire is heated for t2min, the intelligently controlled power supply device stops supplying current to the heating wire; at the same time, the negative pole of the intelligently controlled power supply device is connected to the anode, and the positive pole is connected to the heating wire, and a loop is formed, so that cathode peeling occurs on the surface of the anode; 5) After the remaining wax layer is completely peeled off, the intelligently controlled power supply device restarts the cathodic protection circuit, so that the protected tank body continues to be in the current cathodic protection state.

6. A protection method for a cathodic protection system of a wax deposition container according to claim 5, characterized in that: In step 2, the preset value is 1.6 times the normal voltage of the cathode protection circuit.

7. The protection method for a cathodic protection system of a wax deposition container according to claim 5, characterized in that: In step 2, t1 is 1.

8. The protection method for a cathodic protection system of a wax deposition container according to claim 5, characterized in that: The t2 in step 4 is 3-5.

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