Pipeline anti-corrosion device based on thermoelectric power generation

Abstract

The invention relates to a pipeline anticorrosion device based on thermoelectric power generation, and belongs to the technical field of pipeline anticorrosion. Comprising a thermoelectric power generation system, an energy storage control system and an electrochemical anti-corrosion system, the thermoelectric power generation system generates electric energy through the temperature difference between a pipeline and the environment, the electric energy is transmitted to the energy storage control system through a power transmission line, the energy storage control system is responsible for storing the electric energy transmitted by the thermoelectric power generation sheet and secondarily distributing the electric energy to the electrochemical corrosion prevention system, and the anode of the electrochemical corrosion prevention system is connected with the anode of the energy storage control system. And the cathode of the electrochemical anti-corrosion system is connected with a pipeline needing anti-corrosion. The thermoelectric power generation technology and the electrochemical corrosion prevention technology are integrated, power is generated through the temperature difference between the pipeline and the environment, corrosion prevention of the pipeline is achieved without an external power source, the corrosion speed of the pipeline can be effectively reduced, environmental pollution is reduced, the service life of the pipeline is prolonged, and cost is saved.

Description

Technical Field

[0001] The invention relates to a pipeline anti-corrosion device based on temperature difference power generation, belonging to the technical field of pipeline anti-corrosion. Background Art

[0002] At present, the anti-corrosion technologies for petroleum and sewage pipelines at home and abroad mainly include hot-dip galvanizing technology, electrolytic galvanizing technology, thermal spraying technology, thermal spraying technology, thermal powder spraying technology, and anti-corrosion paint, among which hot-dip galvanizing technology has the best anti-corrosion effect, but the cost is relatively high. Although other technologies have low costs, the anti-corrosion effect is not good. The above technologies are suitable for pipeline anti-corrosion in a short period of time. For petroleum and sewage pipelines that operate in saline-alkali environments for a long time or have an operating period of more than 10 years, other anti-corrosion technologies need to be used. Summary of the invention

[0003] In order to solve the above-mentioned problems existing in the prior art, the present invention discloses a pipeline anti-corrosion device based on temperature difference power generation. Without connecting to an external power supply, the device generates electric energy through the temperature difference between the pipeline and the environment to place the pipeline at an absolute negative potential of -0.85V--1.3V, thereby preventing corrosive ions from contacting the pipeline, achieving the pipeline anti-corrosion effect, reducing the difficulty and cost of pipeline anti-corrosion, and saving costs.

[0004] The technical solution adopted by the present invention is: a pipeline anti-corrosion device based on temperature difference power generation, including a temperature difference power generation system, an energy storage control system, and an electrochemical anti-corrosion system; the temperature difference power generation system generates electric energy through the temperature difference between the pipeline and the environment, and the electric energy is transmitted to the energy storage control system through the transmission line. The energy storage control system is responsible for storing the electric energy transmitted by the temperature difference power generation sheet and redistributing the electric energy to the electrochemical anti-corrosion system. The positive electrode of the electrochemical anti-corrosion system is connected to the positive electrode of the energy storage control system; the negative electrode of the electrochemical anti-corrosion system is connected to the pipeline that needs to be anti-corroded.

[0005] Furthermore, the electrochemical anti-corrosion system includes an auxiliary anode block and an anode bed, the auxiliary anode block is arranged in the anode bed and buried underground, and the auxiliary anode block and the anode bed are connected to the positive electrode of the energy storage control system through a wire. A fixing clamp is provided on the pipeline for fixing the wire connected to the negative electrode of the energy storage control system.

[0006] Furthermore, the temperature difference power generation system is a temperature difference power generation sheet, the high temperature end is in contact with the outer surface of the pipeline, and the low temperature end is in contact with the environment, and electricity is generated through the temperature difference between the pipeline and the environment.

[0007] Furthermore, the energy storage control system includes a battery U1 and a DC voltage stabilizing circuit. The DC voltage stabilizing circuit is a switch device T1 connected in parallel to the output end of the thermoelectric generator E. When the battery voltage is greater than the rated voltage, the switch device T1 is turned on, and the anti-reverse charging diode D1 is turned off. Then, the output current of the thermoelectric generator E is directly discharged through the short circuit of T1, and the battery is no longer charged. Only when the output voltage of the thermoelectric generator E is greater than the battery voltage, D1 can be turned on, otherwise D1 is turned off.

[0008] The voltage regulator diode D2 is connected in parallel with the load resistor RL. The voltage on the voltage regulator diode D2 is the output voltage U2. R1 is the current limiting resistor. The unstabilized DC working voltage is added to the voltage regulator diode D2 through R1. Since U1 is much larger than the voltage regulation value of D2, D2 enters the working state, and a stable DC voltage is obtained at its two ends, which serves as the output voltage of the voltage regulator circuit.

[0009] Furthermore, the auxiliary anode block material is one or more of graphite, iron, aluminum and zinc.

[0010] Furthermore, the connection position between the negative electrode of the electrochemical anti-corrosion system and the pipeline is 20 centimeters above the ground.

[0011] Furthermore, the buried depth of the auxiliary anode block is half of the underground depth of the pipeline.

[0012] The present invention discloses a pipeline anti-corrosion device based on temperature difference power generation. The beneficial effect is that the present invention integrates temperature difference power generation technology and electrochemical anti-corrosion technology, generates electricity through the temperature difference between the pipeline and the environment, and realizes anti-corrosion of the pipeline without an external power supply. It can effectively reduce the corrosion rate of the pipeline, reduce environmental pollution, extend the service life of the pipeline, and save costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the present invention 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, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0014] Figure 1 : A schematic diagram of the structure of an embodiment of the present invention;

[0015] Figure 2 : Schematic diagram of the structure of the thermoelectric power generation chip;

[0016] Figure 3 : Schematic diagram of DC voltage stabilization circuit.

[0017] In the figure: 1. Soil; 2. Pipeline; 3. Thermoelectric generator; 4. Energy storage control system; 5. Anode bed; 6. Auxiliary anode block; 7. Fixing clamp.

[0018] Specific implementation methods

[0019] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] In order to further understand the content of the present invention, the present invention is further described below in conjunction with specific implementation methods. Example 1

[0021] like Figure 1-3 As shown, the pipeline anti-corrosion device based on temperature difference power generation includes a temperature difference power generation system, an energy storage control system 4, and an electrochemical anti-corrosion system; the temperature difference power generation system generates electric energy through the temperature difference between the pipeline 2 and the environment, and the electric energy is transmitted to the energy storage control system 4 through the transmission line. The energy storage control system 4 stores the electric energy and distributes the electric energy to the electrochemical anti-corrosion system for a second time, and the positive electrode of the electrochemical anti-corrosion system is connected to the positive electrode of the energy storage control system 4; the negative electrode of the electrochemical anti-corrosion system is connected to the pipeline 2, and the connection position of the negative electrode of the electrochemical anti-corrosion system and the pipeline 2 is 20 cm above the ground, so that the pipeline 2 is maintained at an absolute negative potential of -0.85V to -1.3V, which hinders Cl in the environment - , The corrosive ions are in contact with the pipeline 2, which plays an electrochemical anti-corrosion role on the pipeline 2 in the soil 1 and prolongs the service life of the pipeline 2.

[0022] The electrochemical anti-corrosion system includes an anode bed 5, an auxiliary anode block 6 and a fixing clamp 7. The auxiliary anode block 6 is arranged in the anode bed 5 and buried underground. The auxiliary anode block 6 and the anode bed 5 are both connected to the positive electrode of the energy storage control system 4 through a wire. The pipeline 2 is provided with a fixing clamp 7 for fixing the wire connected to the negative electrode of the energy storage control system 4.

[0023] Figure 1The middle is the soil 1 environment where the pipeline 2 is located. Some oil and gas pipelines 2 have high-salt and high-alkali environments. The pipeline 2 is responsible for transporting the medium. There are multiple expansion bends in the middle of the long-distance pipeline 2. The expansion bends are prone to corrosion and leakage at the contact end with the soil 1. The thermoelectric system is a thermoelectric sheet 3. The thermoelectric sheet 3 is a power generation device that uses the Seebeck effect to directly convert thermal energy into electrical energy. A p-type thermoelectric element and an n-type thermoelectric element are connected at their high-temperature ends with metal conductor electrodes, and cold-end electrodes are connected at their low-temperature ends to form a thermoelectric monomer or a single couple. An external load is connected to the open-circuit end of the thermoelectric monomer. If a heat flow is input to the hot surface of the thermoelectric monomer, a temperature difference is established between the high-temperature end and the low-temperature end of the thermoelectric monomer, and current will flow through the circuit, thus obtaining a generator that directly converts thermal energy into electrical energy. The high-temperature end of the thermoelectric sheet 3 contacts the outer surface of the pipeline 2, and the low-temperature end of the thermoelectric sheet 3 contacts the environment, and electricity is generated through the temperature difference between the pipeline and the environment. The temperature difference between the pipe 2 and the environment causes fluctuations in the power generation of the thermoelectric generator 3. The current is stored in the battery and used to supply power to the electrochemical corrosion protection system. The output voltage of the battery is unstable. To ensure that the electrochemical corrosion protection system is provided with a continuous and stable voltage, the semiconductor voltage regulator diode has the characteristic that the voltage at both ends remains basically unchanged despite the current varying within a large range in the reverse breakdown state. Using this characteristic of the voltage regulator diode, a DC voltage regulator circuit is provided. Figure 3 As shown, the energy storage control system 4 includes a battery and a DC voltage stabilizing circuit. The DC voltage stabilizing circuit is a switch device T1 connected in parallel to the output end of the thermoelectric generator E. When the battery voltage is greater than the rated voltage, the switch device T1 is turned on, and the anti-recoil diode D1 is turned off. Then the output current of the thermoelectric generator E is directly discharged through the short circuit of T1, and the battery is no longer charged, thereby ensuring that the battery will not be overcharged, playing the role of "overcharge protection". D1 is an anti-reverse charging diode. Only when the output voltage of the thermoelectric generator E is greater than the battery voltage, D1 can be turned on, otherwise D1 is turned off, thereby ensuring that the battery will not reversely charge the thermoelectric generator E, playing the role of "anti-reverse charging protection".

[0024] The voltage regulator diode D2 is connected in parallel with the load resistor RL. The voltage on the voltage regulator diode D2 is the output voltage U2. R1 is the current limiting resistor. The unstabilized DC working voltage is added to the voltage regulator diode D2 through R1. Since U1 is much larger than the voltage regulation value of D2, D2 enters the working state, and a stable DC voltage is obtained at its two ends, which serves as the output voltage of the voltage regulator circuit.

[0025] Take the crude oil pipeline of a joint station in Panjin City as an example:

[0026] The temperature of the crude oil pipeline is 50℃-80℃, the ambient temperature is -20℃-30℃, and the temperature difference throughout the year is 50℃-70℃, which meets the power generation requirements of the temperature difference power generation sheet.

[0027] The crude oil pipeline is 12.5 kilometers long, of which 12 kilometers are in highly saline and alkaline soil. The pipeline passes through environmental protection areas, reed fields, rice fields, fish ponds and other areas. The annual environmental pollution cost due to pipeline leakage is 2.1 million yuan, the pollution cleaning cost is 120,000 yuan, and the pipeline leak repair cost is 50,000 yuan. The crude oil leakage has caused irreparable damage to the environment. The crude oil pipeline has 7 expansion bends, and 7 sets of pipeline anti-corrosion devices can be installed. Each set costs 300 yuan, and the annual operation and maintenance cost is 10,000 yuan. It is expected that the number of pipeline leakage point sources can be reduced to 1 / 2.

[0028] Can save various costs J =

[0029] (210+12+5*10000*1 / 2-300*7-10000=1122900=1.1229 million yuan

[0030] Theoretical calculation:

[0031] Analysis of pipeline electrochemical corrosion protection power

[0032] The buried part of the pipeline is simplified into two cylinders with a diameter of d = 0.15m and a length of L = 1m.

[0033] Pipeline surface area: S 1 =πdL=0.15π.

[0034] Pipeline protection current density: i=10mA / m 2 ,

[0035] Total loop current: I = 2iS 1 =9.4mA.

[0036] Required auxiliary anode block mass: G t =TgI / K=0.038kg,

[0037] Required auxiliary anode block volume: V = G t / ρ=18.1cm 3 According to the data, take the diameter d 石墨 =3cm, length L 石墨 =3.8cm graphite body as auxiliary anode block.

[0038] Buried depth t = 1.9m, diameter D 焦炭 =20cm, length L 焦炭 =60cm of coke is used as the anode bed.

[0039] Soil resistivity: ρ 土壤 =200Ω.m

[0040] Coke resistivity: ρ 焦炭 =50Ω.mAnode: Contact resistance between graphite and coke:

[0041] Contact resistance between coke and soil:

[0042] Anode potential:

[0043] U 1 =I(R V1 +R V2) =1.59V

[0044] Cathode: Contact resistance between pipeline and soil:

[0045] Cathode potential:

[0046] U 2 =-iS 1 R V3 =-0.49V

[0047] Power consumption of electrochemical corrosion protection: P' = I (U 1 -U 2 )=0.02W

[0048] Power required for electrochemical corrosion protection:

[0049]

[0050] (η is the power efficiency, here it is 0.8)Thermoelectric generator performance parametersProduct model: SP1848-27145 SA.Principle: Seeback effect

[0051] Operating environment: -60~125℃

[0052] Product raw materials: Bismuth telluride

[0053] Crystal rod specifications: Ф30mm L-30cm

[0054] Thermoelectric parameters:

[0055] Thermoelectric potential (a):>190×μV / ℃

[0056] Conductivity (σ): 850~1250Ω -1 .cm -1

[0057] Merit value (Z): 2.5~3.0×10 -3 W / ℃

[0058] Generator size: 40mm long * 40mm wide * 3.6mm thick

[0059] The red wire is connected to the positive pole, and the black wire is connected to the negative pole. When there is a temperature difference, it can generate electricity.

[0060] Temperature difference 50℃: open circuit voltage 2.1V, power generation current: 418mA, power generation power 0.88W

[0061] Temperature difference 60℃: open circuit voltage 2.4V, power generation current: 469mA, power generation power 1.13W

[0062] Temperature difference 70℃: open circuit voltage 3.0V, power generation current: 514mA, power generation power 1.54W

[0063] In summary, it can be seen that only one temperature difference power generation sheet is needed to meet the power requirements of electrochemical corrosion protection.

[0064] Principle of temperature difference power generation system

[0065] There are a certain number of carriers (such as electrons or holes) inside the semiconductor. The density of these carriers will change with the change of temperature. If the temperature at one end of the object is high and the temperature at the other end is low, different carrier densities will appear in the middle of the same object. As long as the temperature difference between the two ends of the object can be maintained, the carriers can continue to diffuse, thus forming a stable voltage.

[0066] Energy storage control system principle

[0067] The system includes batteries and rectifiers, which can convert excess electrical energy into chemical energy and store it inside the battery, and then convert unstable electrical energy into stable electrical energy through the rectifier to ensure the power supply effect of the energy storage control system.

[0068] Electrochemical anti-corrosion system

[0069] The positive electrode of the electrochemical anti-corrosion system is connected to the auxiliary anode, and the auxiliary anode is filled with coke. The negative electrode of the electrochemical anti-corrosion system is connected to the middle and lower part of the pipeline to better protect the pipeline that is easily corroded in the soil. The negative electrode of the electrochemical anti-corrosion system is connected to the pipeline to keep the pipeline at an absolute negative potential of -0.85V to -1.3V, which prevents Cl in the environment from - , The corrosive ions come into contact with the pipeline, which plays an electrochemical anti-corrosion role on the pipeline in the soil.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A pipeline anti-corrosion device based on temperature difference power generation, characterized in that: It comprises a temperature difference power generation system, an energy storage control system (4), and an electrochemical corrosion protection system; the temperature difference power generation system generates electric energy through the temperature difference between the pipeline (2) and the environment, and the electric energy is transmitted to the energy storage control system (4) through the transmission line; the energy storage control system (4) is responsible for storing the electric energy transmitted by the temperature difference power generation sheet (3) and redistributing the electric energy to the electrochemical corrosion protection system; the positive electrode of the electrochemical corrosion protection system is connected to the positive electrode of the energy storage control system (4); the negative electrode of the electrochemical corrosion protection system is connected to the pipeline (2) that needs to be protected from corrosion.

2. The pipeline anti-corrosion device based on temperature difference power generation according to claim 1 is characterized in that: The electrochemical anti-corrosion system comprises an auxiliary anode block (6) and an anode bed (5), wherein the auxiliary anode block (6) is arranged in the anode bed (5) and buried underground, and the auxiliary anode block (6) and the anode bed (5) are both connected to the positive electrode of the energy storage control system (4) through a wire; and a fixing clamp (7) is provided on the pipeline (2), and the fixing clamp (7) is used to fix the wire connected to the negative electrode of the energy storage control system (4).

3. The pipeline anti-corrosion device based on temperature difference power generation according to claim 1 is characterized in that: The temperature difference power generation system is a temperature difference power generation sheet (3), the high temperature end of which is in contact with the outer surface of the pipeline (2) and the low temperature end of which is in contact with the environment, and generates electricity through the temperature difference between the pipeline and the environment.

4. The pipeline anti-corrosion device based on temperature difference power generation according to claim 1 is characterized in that: The energy storage control system (4) comprises a storage battery U1 and a DC voltage stabilizing circuit. The DC voltage stabilizing circuit is a switch device T1 connected in parallel to the output end of the thermoelectric generator E. When the storage battery voltage is greater than the rated voltage, the switch device T1 is turned on and the reverse charging prevention diode D1 is turned off. Then, the output current of the thermoelectric generator E is directly discharged through the short circuit of T1 and the storage battery is no longer charged. Only when the output voltage of the thermoelectric generator E is greater than the storage battery voltage, D1 can be turned on, otherwise D1 is turned off. The voltage regulator diode D2 is connected in parallel with the load resistor RL. The voltage on the voltage regulator diode D2 is the output voltage U2. R1 is the current limiting resistor. The unstabilized DC working voltage is added to the voltage regulator diode D2 through R1. Since U1 is much larger than the voltage regulation value of D2, D2 enters the working state, and a stable DC voltage is obtained at its two ends, which serves as the output voltage of the voltage regulator circuit.

5. The pipeline anti-corrosion device based on temperature difference power generation according to claim 2 is characterized in that: The auxiliary anode block (6) is made of one or more of graphite, iron, aluminum and zinc.

6. The pipeline anti-corrosion device based on temperature difference power generation according to claim 1 is characterized in that: The connection position between the negative electrode of the electrochemical anti-corrosion system and the pipeline (2) is 20 centimeters above the ground.

7. The pipeline anti-corrosion device based on temperature difference power generation according to claim 2 is characterized in that: The buried depth of the auxiliary anode block (6) is half of the underground depth of the pipeline (2).

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