CN113624667B - Method for determining service life of long oil and gas pipeline - Google Patents
Method for determining service life of long oil and gas pipeline Download PDFInfo
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- CN113624667B CN113624667B CN202010387367.9A CN202010387367A CN113624667B CN 113624667 B CN113624667 B CN 113624667B CN 202010387367 A CN202010387367 A CN 202010387367A CN 113624667 B CN113624667 B CN 113624667B
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- 238000000034 method Methods 0.000 title claims abstract description 34
- 238000005260 corrosion Methods 0.000 claims abstract description 198
- 230000007797 corrosion Effects 0.000 claims abstract description 191
- 230000007547 defect Effects 0.000 claims abstract description 65
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 51
- 229910052802 copper Inorganic materials 0.000 claims abstract description 51
- 239000010949 copper Substances 0.000 claims abstract description 51
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 42
- 239000010959 steel Substances 0.000 claims abstract description 42
- 230000005540 biological transmission Effects 0.000 claims description 31
- 238000012360 testing method Methods 0.000 claims description 18
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 6
- 229910052744 lithium Inorganic materials 0.000 claims description 6
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 3
- 239000011248 coating agent Substances 0.000 claims description 3
- 238000000576 coating method Methods 0.000 claims description 3
- 229910000365 copper sulfate Inorganic materials 0.000 claims description 3
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 claims description 3
- 229910052749 magnesium Inorganic materials 0.000 claims description 3
- 239000011777 magnesium Substances 0.000 claims description 3
- 125000006850 spacer group Chemical group 0.000 claims description 2
- 239000000853 adhesive Substances 0.000 claims 2
- 230000001070 adhesive effect Effects 0.000 claims 2
- 238000001514 detection method Methods 0.000 abstract description 4
- 239000007789 gas Substances 0.000 description 77
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 17
- 239000001257 hydrogen Substances 0.000 description 17
- 229910052739 hydrogen Inorganic materials 0.000 description 17
- 239000002689 soil Substances 0.000 description 6
- 238000005536 corrosion prevention Methods 0.000 description 4
- 238000002474 experimental method Methods 0.000 description 4
- 230000007774 longterm Effects 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 3
- 239000004698 Polyethylene Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000005684 electric field Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000005404 monopole Effects 0.000 description 1
- -1 polyethylene Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000011895 specific detection Methods 0.000 description 1
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N19/00—Investigating materials by mechanical methods
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/20—Metals
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
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Abstract
The application discloses a method for determining the service life of a long oil and gas pipeline, and belongs to the field of long oil and gas pipelines. The method comprises the following steps: copper sheets on the binding posts 42, 43 and 46 are respectively connected with the binding posts 40, 45 and 48, the output voltage of the power supply 6 is the target voltage, after a preset unit time, the corrosion defect depth of the corrosion layer of the anode pipe section 1, the adhesion force of the corrosion layer of the cathode pipe section 2 and the yield stress of the steel sample 8 are detected, the copper sheets are added into the preset corresponding relation among the voltage, the corrosion defect depth of the corrosion layer, the adhesion force of the corrosion layer and the yield stress, the actual voltage of the target long oil and gas pipeline is detected, and the service life of the target long oil and gas pipeline is determined according to the corresponding relation, the preset upper limit of the corrosion defect depth of the corrosion layer, the preset upper limit of the adhesion force of the corrosion layer and the preset lower limit of the yield stress. The long service life of the oil and gas pipeline determined by the method shortens the detection period, so that the timeliness is good.
Description
Technical Field
The application relates to the field of long oil and gas pipeline, in particular to a method for determining the service life of a long oil and gas pipeline.
Background
When a monopole ground loop is adopted, namely an operation mode of forming the loop through the grounding electrode, if the buried long oil and gas pipeline is positioned between the grounding electrodes, thousands of volts of interference voltage can be generated on the long oil and gas pipeline, and after a long period, the damage of corrosion, hydrogen embrittlement and stripping of an anticorrosive layer of the long oil and gas pipeline can be brought to the long oil and gas pipeline. In order to rapidly evaluate the damage degree and predict the service life of the long oil and gas pipeline, it is necessary to provide a method for determining the corrosion degree of the long oil and gas pipeline to simulate the corrosion process of the long oil and gas pipeline disturbed by the long-term voltage of the high-voltage transmission line.
In the related art, the interference voltage generated by the high-voltage direct-current transmission line can interfere the whole surface of the long oil and gas pipeline, the pipe section surface (equivalent to a cathode) of the long oil and gas pipeline, which is close to the grounding electrode, can absorb current, so that the corrosion-resistant layer of the pipe section surface is stripped and hydrogen embrittled, and the pipe section surface (equivalent to an anode) which is far from the grounding electrode can flow out of the current to the ground again, so that the pipe body of the pipe section surface is corroded. After a long period, a technician can dig out the long oil and gas pipeline at intervals on the long oil and gas pipeline operation site, measure the corrosion defect depth of the corrosion layer of the long oil and gas pipeline, and if the measured corrosion defect depth of the corrosion layer reaches the upper limit value of the depth, the time is taken as the service life of the long oil and gas pipeline.
In carrying out the application, the inventors have found that the prior art has at least the following problems:
In the method, technicians can obtain the conditions of corrosion, hydrogen embrittlement and stripping of the corrosion-resistant layer of the long oil and gas pipeline after a long period, and further determine the service life of the long oil and gas pipeline, so that the timeliness is poor.
Disclosure of Invention
The embodiment of the application provides a method for determining the service life of a long oil and gas pipeline, which can solve the problem of poor timeliness for obtaining the damage degree of corrosion, hydrogen embrittlement and stripping of an anti-corrosion layer of the long oil and gas pipeline. The technical scheme is as follows:
The method is applied to a device for determining the service life of a long oil and gas pipeline, and the device for determining the service life of the long oil and gas pipeline comprises the following steps: the device comprises an anode tube section 1, a cathode tube section 2, a plurality of long-acting reference electrodes 3, a test pile 4, a sacrificial anode 5, a power supply 6, a pre-stress bracket 7, a steel sample 8 and a plurality of wires, wherein the pre-stress bracket 7 comprises a loading bolt 70, a frame 71 and a fixing bolt 72, the steel sample 8 is fixed on the frame 71 through the loading bolt 70 and the fixing bolt 72, the loading bolt 70 is used for applying preset stress to the steel sample 8, the anode tube section 1 and the cathode tube section 2 are long oil and gas pipeline samples, the steel sample 8 is a slice of the long oil and gas pipeline samples, the surfaces of the anode tube section 1 and the cathode tube section 2 are provided with preset corrosion-resistant layer defects, the anode tube section 1 and the cathode tube section 2 are arranged in parallel in the horizontal direction at a first preset distance and are buried in the ground of a preset depth, a long-acting reference electrode 3 is arranged at a second preset distance between the anode tube section 1 and the cathode tube section 2, the test pile 4 comprises a base 410 and a binding post 40, a binding post 41, a binding post 42, a binding post 43, a binding post 44, a binding post 45, a binding post 46, a binding post 47, a binding post 48 and a binding post 49 which are arranged on the base 410, copper sheets which are freely rotated are arranged on the binding post 42, the binding post 43 and the binding post 46, the anode tube section 1 is connected with the binding post 40 and the binding post 43 respectively through wires, the cathode tube section 2 is connected with the binding post 48 and the binding post 45 respectively through wires, the positive electrode of a power supply 6 is connected with the binding post 42, the negative electrode of the power supply 6 is connected with the binding post 46, one long-acting reference electrode 3 is connected with the binding post 41 through wires, the other long-acting reference electrode 3 is connected with the binding post 49 through wires, and a steel sample 8 is connected with the binding post 48 through wires, and the method comprises:
Connecting the copper piece on the binding post 42 with the binding post 40, connecting the copper piece on the binding post 46 with the binding post 48, connecting the copper piece on the binding post 43 with the binding post 45, and setting the output voltage of the power supply 6 to be a target voltage;
after a preset unit time length, detecting the corrosion defect depth of the corrosion layer of the anode tube section 1, the adhesion force of the corrosion layer of the cathode tube section 2 and the yield stress of the steel sample;
adding the target voltage, the corrosion defect depth of the corrosion protection layer, the adhesion force of the corrosion protection layer and the yield stress into the pre-established corresponding relation of the voltage, the corrosion defect depth of the corrosion protection layer, the adhesion force of the corrosion protection layer and the yield stress;
Detecting the actual voltage of a target long-distance oil and gas pipeline, and determining the corrosion defect depth, the adhesion force of the corrosion layer and the yield stress of the corrosion layer corresponding to the actual voltage based on the corresponding relation;
And determining the service life of the target long oil and gas pipeline based on the preset upper limit of corrosion defect depth of the corrosion layer, the preset upper limit of adhesion force of the corrosion layer and the preset lower limit of yield stress, and the corrosion defect depth of the corrosion layer, the adhesion force of the corrosion layer and the preset yield stress corresponding to the actual voltage.
Optionally, the copper piece is provided on the post 47, the copper piece on the post 42 is connected to the post 40, the copper piece on the post 46 is connected to the post 48, the copper piece on the post 47 is disconnected from the post 45, and the output voltage of the power supply 6 is set to the target voltage, before the method further includes:
disconnecting the copper sheet on the binding post 42 from the binding post 40, disconnecting the copper sheet on the binding post 46 from the binding post 48, and connecting the copper sheet on the binding post 47 with the binding post 45;
Detecting a voltage between the terminal 45 and the terminal 47, determining that the voltage is less than a preset voltage threshold;
When the copper piece on the post 42 is connected to the post 40, the copper piece on the post 46 is connected to the post 48, the copper piece on the post 43 is connected to the post 45, and the output voltage of the power supply 6 is set to the target voltage, the copper piece on the post 47 is disconnected from the post 45.
Alternatively, both ends of the anode tube section 1 are provided with hard caps, and both ends of the anode tube section 2 are provided with hard caps.
Optionally, the long-acting reference electrode 3 is a long-acting copper sulfate reference electrode.
Optionally, the test stake 4 is disposed at an intermediate position between the anode tube segment 1 and the cathode tube segment 2.
Alternatively, the sacrificial anode 5 is a pre-packaged magnesium anode.
Alternatively, the sacrificial anode 5 is buried in the middle of the anode segment 1 and the cathode segment 2.
Alternatively, the power source 6 is a lithium battery pack.
Optionally, an insulating spacer is provided between the steel sample 8 and the load bolt 70.
Optionally, determining the service life of the target long oil delivery pipe based on the preset upper limit of corrosion defect depth of the corrosion layer, the preset upper limit of adhesion of the corrosion layer, the preset upper limit of yield stress, and the corrosion defect depth of the corrosion layer, the preset adhesion of the corrosion layer and the preset yield stress, which correspond to the actual voltage, includes:
based on a preset corrosion defect depth upper limit, a corrosion resistance adhesion upper limit, a yield stress lower limit and a formula of the corrosion resistance Respectively obtaining a first use duration, a second use duration and a third use duration of the target long oil and gas pipeline, wherein T 1 is the first use duration, T 2 is the second use duration, T 3 is the third use duration, M 1 is the upper limit of corrosion defect depth of the corrosion layer, M 2 is the upper limit of adhesion strength of the corrosion layer, M 3 is the lower limit of yield stress, N 1 is the depth of corrosion defect of the corrosion layer corresponding to the actual voltage, N 2 is adhesion strength of the corrosion layer corresponding to the actual voltage, and N 3 is the yield stress corresponding to the actual voltage;
And determining the minimum use time length as the service life of the target long oil and gas transmission pipe in the first use time length, the second use time length and the third use time length of the target long oil and gas transmission pipe.
The technical scheme provided by the embodiment of the application has the beneficial effects that:
The device is formed by an anode tube section 1, a cathode tube section 2, a plurality of long-acting reference electrodes 3, a test pile 4, a sacrificial anode 5, a power supply 6, a prestress bracket 7, a steel sample 8 and a plurality of wires, and the damage degree of stripping, hydrogen embrittlement and corrosion of a pipe body of an anticorrosive layer caused by interference voltage generated by a high-voltage direct-current transmission line in an actual scene to a long-term oil and gas pipeline is simulated. The copper sheets on the binding post 42, the binding post 43 and the binding post 46 are respectively connected with the binding post 40, the binding post 45 and the binding post 48, the output voltage of the power supply 6 is set to be the target voltage, after a preset unit time, namely after a short period, the corrosion defect depth of the corrosion layer of the anode pipe section 1, the adhesion force of the corrosion layer of the cathode pipe section and the yield stress of a steel sample are detected, the damage degree of corrosion, hydrogen embrittlement and peeling of the corrosion layer of the long oil and gas pipeline body can be obtained, and the service life of the long oil and gas pipeline is determined based on the preset upper limit of the corrosion defect depth of the corrosion layer, the preset upper limit of the adhesion force of the corrosion layer, the preset lower limit of the yield stress and the corrosion defect depth of the corrosion layer, the adhesion force of the corrosion layer and the yield stress corresponding to the actual voltage, the detection period is shortened, and therefore the timeliness is good.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a device for determining the service life of a long oil and gas pipeline according to an embodiment of the present application;
FIG. 2 is a flow chart of a method for determining the service life of a long oil and gas pipeline according to an embodiment of the present application.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present application more apparent, the embodiments of the present application will be described in further detail with reference to the accompanying drawings.
The embodiment of the application provides a method for determining the service life of a long oil and gas pipeline, which is applied to a device for determining the service life of the long oil and gas pipeline, and fig. 1 is a structural diagram of the device for determining the service life of the long oil and gas pipeline, and referring to fig. 1, the device for determining the service life of the long oil and gas pipeline comprises: the device comprises an anode tube section 1, a cathode tube section 2, a plurality of long-acting reference electrodes 3, a test pile 4, a sacrificial anode 5, a power supply 6, a pre-stress bracket 7, a steel sample 8 and a plurality of wires, wherein the pre-stress bracket 7 comprises a loading bolt 70, a frame 71 and a fixing bolt 72, the steel sample 8 is fixed on the frame 71 through the loading bolt 70 and the fixing bolt 72, the loading bolt 70 is used for applying preset stress to the steel sample 8, the anode tube section 1 and the cathode tube section 2 are long oil and gas pipeline samples, the steel sample 8 is a slice of the long oil and gas pipeline samples, the surfaces of the anode tube section 1 and the cathode tube section 2 are provided with preset corrosion-resistant layer defects, the anode tube section 1 and the cathode tube section 2 are arranged in parallel in the horizontal direction at a first preset distance and are buried in the ground of a preset depth, the long-acting reference electrode 3 is arranged at a second preset distance between the anode tube section 1 and the cathode tube section 2, the test pile 4 comprises a base 410 and a binding post 40, a binding post 41, a binding post 42, a binding post 43, a binding post 44, a binding post 45, a binding post 46, a binding post 47, a binding post 48 and a binding post 49 which are arranged on the base 410, copper sheets which are freely rotated are arranged on the binding post 42, the binding post 43 and the binding post 46, the anode tube section 1 is connected with the binding post 40 and the binding post 43 respectively through wires, the cathode tube section 2 is connected with the binding post 48 and the binding post 45 respectively through wires, the positive electrode of the power supply 6 is connected with the binding post 42, the negative electrode of the power supply 6 is connected with the binding post 46, one long-acting reference electrode 3 is connected with the binding post 41 through wires, the other long-acting reference electrode 3 is connected with the binding post 49 through wires, and the steel sample 8 is connected with the binding post 48 through wires.
The anode tube section 1 and the cathode tube section 2 are used for simulating a long oil and gas pipeline in an actual scene, and the outer walls of the anode tube section 1 and the cathode tube section 2 are coated with corrosion-resistant layers of the same type. The cathode tube section 2 represents the tube section surface of the long oil and gas pipeline, which is close to the grounding electrode of the high-voltage direct-current transmission line, when the high-voltage direct-current transmission line near the long oil and gas pipeline generates an interference electric field to the high-voltage direct-current transmission line, the tube section surface can absorb current from the high-voltage direct-current transmission line in soil, so that the tube section surface can be damaged by stripping and hydrogen embrittlement of an anticorrosive coating, and the anode tube section 1 represents the tube section surface far away from the grounding electrode of the high-voltage direct-current transmission line, and can flow out of the current to the ground again, so that the tube section surface can be damaged by corrosion of a tube body. The anode tube section 1 and the cathode tube section 2 are arranged in parallel in the horizontal direction, the distance is more than 3 meters, and the anode tube section and the cathode tube section are buried in soil, and the buried depth is the same as the buried depth of a long oil and gas pipeline in an actual scene.
In practice, corrosion defects of corrosion protection layers with different shapes and different area sizes are arranged on the outer wall of the anode pipe section 1 and the outer wall of the cathode pipe section 2 in different clock directions.
For example, a set of corrosion defects of a circular shape having an area size of 1 square centimeter, 5 square centimeters and 10 square centimeters and a rectangular shape having a length of 10 centimeters and a width of 0.5 centimeters are provided on the outer wall of the anode tube segment 1 and the cathode tube segment 2 in the 0, 3 and 6 clock orientations, respectively. The embodiment of the application does not limit the size and shape of the area of the corrosion defect.
In implementation, both ends of the anode tube section 1 are provided with hard tube caps, and both ends of the anode tube section 2 are provided with hard tube caps for simulating the closed state of the long oil and gas pipeline in an actual scene.
The long-acting reference electrode 3 is used for detecting the electric potential of the anode tube section 1 and the cathode tube section 2 under the sacrificial anode protection method, namely, is matched with a universal meter for use, and detects the voltages in the anode tube section 1 and the cathode tube section 2 through the universal meter, and it is to be noted that the two long-acting reference electrodes 3 are respectively arranged at the second preset distance of the anode tube section 1 and the cathode tube section 2, and only provide voltage reference potential, do not need to be connected into a circuit, only need to use a lead to guide the position of the wiring pile 4, and are convenient to test.
In practice, the long-acting reference electrode 3 is a long-acting copper sulfate reference electrode.
The test pile 4 is used for simulating circuit connection of corrosion damage of corrosion-resistant layers, hydrogen embrittlement and pipe bodies of long oil and gas transmission pipelines caused by interference voltage generated by a high-voltage direct-current transmission line in an actual scene, and is arranged in the middle of the anode pipe section 1 and the cathode pipe section 2. The test pile 4 comprises a base 410, wherein 10 binding posts 40, 41, 42, 43, 44, 45, 46, 47, 48 and 49 are arranged on the base 410, and copper sheets capable of freely rotating are arranged on the binding posts 42, 43, 46 and 47 and used for being communicated with or disconnected from other binding posts.
The sacrificial anode 5 is used for simulating the state of the long oil and gas pipeline under the condition that the long oil and gas pipeline has no high-voltage direct-current transmission line interference voltage in an actual scene, and providing electrochemical protection for the long oil and gas pipeline. Namely, when the binding post 45 and the binding post 47 are connected without connecting the power supply 6, the sacrificial anode 5 can be electrolyzed preferentially, so that the damage of corrosion of the anode pipeline 1 caused by the pipe body is restrained, and the damage of corrosion prevention layer peeling and hydrogen embrittlement of the cathode pipeline 2 are prevented.
In practice, the sacrificial anode 5 is a pre-packaged magnesium anode and is buried in the middle of the anode segment 1 and the cathode segment 2.
The power supply 6 is used for simulating the interference voltage generated by the high-voltage direct-current transmission line on the long oil and gas pipeline in an actual scene.
In practice, the power source 6 is a lithium battery pack.
For example, a large-capacity portable lithium battery pack can be adopted, the voltage of the lithium battery pack can be 20V (unit: volt), 120V or 60V and the like, it is noted that an ammeter can be connected into the circuit so as to monitor the change of the current in real time, and if the voltage of the lithium battery pack is found to be insufficient, the battery pack can be used for continuously supplying power in a series connection mode.
The prestress support 7 is used for simulating the damage of hydrogen embrittlement caused by the interference voltage generated by the HVDC transmission line in an actual scene to the long oil and gas transmission pipeline, namely the damage of the hydrogen embrittlement to the cathode tube section 2. The prestress bracket 7 comprises a loading bolt 70, a frame 71 and a fixing bolt 72, the steel sample 8 is fixed on the frame 71 through the loading bolt 70 and the fixing bolt 72, the loading bolt 70 is used for applying preset stress to the steel sample 8, and an insulating gasket is arranged between the steel sample 8 and the loading bolt 70.
It should be noted that, the steel sample 8 is a slice of the long oil and gas pipeline sample, a plurality of steel samples 8 with different steel grades can be set on the prestressed bracket 7, and one steel sample 8 is connected with the binding post 48 through a wire, wherein the steel sample 8 is the same as the steel grade of the anode pipeline 2, and an experiment for determining the service life of the long oil and gas pipeline is completed once. Several steel samples are needed to complete several experiments to determine the service life of the long oil and gas pipeline, namely the steel grades of the anode pipeline 1, the cathode pipeline 2 and the steel sample 8 are the same in the same experiment.
The technical scheme provided by the embodiment of the application has the beneficial effects that:
The device is formed by an anode tube section 1, a cathode tube section 2, a plurality of long-acting reference electrodes 3, a test pile 4, a sacrificial anode 5, a power supply 6, a prestress bracket 7, a steel sample 8 and a plurality of wires, and the damage degree of stripping, hydrogen embrittlement and corrosion of a pipe body of an anticorrosive layer caused by interference voltage generated by a high-voltage direct-current transmission line in an actual scene to a long-term oil and gas pipeline is simulated. The copper sheets on the binding post 42, the binding post 43 and the binding post 46 are respectively connected with the binding post 40, the binding post 45 and the binding post 48, the output voltage of the power supply 6 is set to be the target voltage, after a preset unit time, namely after a short period, the corrosion defect depth of the corrosion layer of the anode pipe section 1, the adhesion force of the corrosion layer of the cathode pipe section and the yield stress of a steel sample are detected, the damage degree of corrosion, hydrogen embrittlement and peeling of the corrosion layer of the long oil and gas pipeline body can be obtained, and the service life of the long oil and gas pipeline is determined based on the preset upper limit of the corrosion defect depth of the corrosion layer, the preset upper limit of the adhesion force of the corrosion layer, the preset lower limit of the yield stress and the corrosion defect depth of the corrosion layer, the adhesion force of the corrosion layer and the yield stress corresponding to the actual voltage, the detection period is shortened, and therefore the timeliness is good.
FIG. 2 is a flow chart of a method for determining the service life of a long oil and gas pipeline according to an embodiment of the present application. Referring to fig. 2, this embodiment includes:
in step 201, the copper piece on the post 42 is connected to the post 40, the copper piece on the post 46 is connected to the post 48, the copper piece on the post 43 is connected to the post 45, and the output voltage of the power supply 6 is set to the target voltage.
The target voltage is used for simulating the interference voltage generated by the high-voltage direct-current transmission line on the long oil and gas pipeline in an actual scene. According to the interference voltage data of the actual high-voltage direct-current transmission line, the target voltage can be voltages with different intensities, for example, 120V, 60V or 20V and the like.
In practice, the copper sheet is provided on the terminal 47, and before the copper sheet on the terminal 42 is connected to the terminal 40, the copper sheet on the terminal 46 is connected to the terminal 48, the copper sheet on the terminal 47 is disconnected from the terminal 45, and the output voltage of the power supply 6 is set to the target voltage, the device for determining the service life of the long oil and gas pipeline needs to be checked to determine the normal operation of the long oil and gas pipeline service life experiment.
For example, the copper piece on the post 42 is disconnected from the post 40, the copper piece on the post 46 is disconnected from the post 48, the copper piece on the post 47 is connected to the post 45, the voltage between the post 45 and the post 47 is detected, it is determined that the voltage is less than the preset voltage threshold, the copper piece on the post 42 is connected to the post 40, the copper piece on the post 46 is connected to the post 48, the copper piece on the post 43 is connected to the post 45, and the copper piece on the post 47 is disconnected from the post 45 when the output voltage of the power supply 6 is set to the target voltage.
Wherein the preset voltage threshold is-1.5V. If the voltage between the terminal 45 and the terminal 47 is detected to be less than-1.5V, the device capable of determining the service life of the long oil and gas pipeline is intact and can be used continuously.
In step 202, after a predetermined unit time period, the corrosion defect depth of the corrosion layer of the anode tube segment 1, the adhesion force of the corrosion layer of the cathode tube segment 2, and the yield stress of the steel sample 8 are detected.
The experimental duration is set according to the interference voltage intensity and the interference time generated by the actual high-voltage direct-current transmission line on the long oil and gas pipeline, and the preset unit duration is in an hour unit.
In practice, the anode tube section 1 is damaged by corrosion of the tube body, and the cathode tube section 2 is damaged by peeling of the anti-corrosion layer and hydrogen embrittlement due to the interference voltage generated by the high-voltage direct-current transmission line. After a preset unit time, the corrosion defect depth of the corrosion layer of the anode tube section 1, the adhesion force of the corrosion layer of the cathode tube section 2 and the yield stress of the steel sample 8 are detected.
For example, for the anode segment 1, a corrosion pit depth meter may be used to detect the depth of the corrosion-preventing layer defect of the anode segment 1, and in addition, the morphology of the corrosion-preventing layer defect may be observed and the corrosion product composition may be analyzed, for example, the shape of the corrosion-preventing layer defect or the color of the corrosion product may be observed, the type of the corrosion-preventing layer defect or the specific composition of the corrosion product may be analyzed, and the like. For the cathode tube section 2, at least 10 cm and not less than three points away from the defect of the corrosion-resistant layer can be used as test points, a tool knife is used for cutting the corrosion-resistant layer with the width of 1 cm, then the corrosion-resistant layer is stretched at a constant speed perpendicular to the surface of the tube body of the cathode tube section 2 by using a spring scale, the adhesion force of the corrosion-resistant layer of the cathode tube section 2 is detected, the adhesion force of the corrosion-resistant layer of the not less than three test points is averaged, and the average value is used as the adhesion force of the corrosion-resistant layer of the cathode tube section 2. In addition, analysis of corrosion product components and the like may be performed. The steel sample 8 was subjected to a steel property influence law test, i.e. by detecting the yield stress.
In step 203, the target voltage, the corrosion defect depth of the corrosion protection layer, the adhesion force of the corrosion protection layer, and the yield stress are added to a pre-established correspondence of voltage, corrosion defect depth of the corrosion protection layer, adhesion force of the corrosion protection layer, and yield stress.
In implementation, after the target voltage is obtained, the target voltage, the corrosion defect depth of the corrosion protection layer, the adhesion force of the corrosion protection layer and the yield stress are correspondingly added into the corresponding relation of the pre-established voltage, the corrosion defect depth of the corrosion protection layer, the adhesion force of the corrosion protection layer and the yield stress.
In step 204, the actual voltage of the target long oil and gas pipeline is detected, and the corrosion defect depth, the adhesion force of the corrosion layer and the yield stress of the corrosion layer corresponding to the actual voltage are determined based on the corresponding relation.
The target long oil and gas pipeline refers to a long oil and gas pipeline in an actual scene of the same material as the anode pipeline 1 and the cathode pipeline 2.
In the implementation, a voltmeter is used for detecting the interference voltage, namely the actual voltage, generated by the high-voltage direct-current transmission line on the target long-distance oil and gas pipeline, and after the actual voltage to be inquired is received, the corrosion defect depth of the corrosion layer, the adhesion force of the corrosion layer and the yield stress of the corrosion layer corresponding to the actual voltage are determined according to the corresponding relation of the pre-established voltage, the corrosion defect depth of the corrosion layer, the adhesion force of the corrosion layer and the yield stress.
In step 205, the service life of the target long oil delivery pipe is determined based on the preset upper limit of corrosion defect depth of the corrosion layer, the preset upper limit of adhesion of the corrosion layer, the preset lower limit of yield stress, and the corrosion defect depth of the corrosion layer, the preset adhesion of the corrosion layer and the preset yield stress corresponding to the actual voltage.
In practice, the upper limit of corrosion defect depth, the upper limit of adhesion of the corrosion layer, the upper limit of yield stress and the formula are based on a preset corrosion defect depth of the corrosion layerThe method comprises the steps of respectively obtaining a first using time length, a second using time length and a third using time length of the target long oil and gas pipeline, wherein T 1 is the first using time length, T 2 is the second using time length, T 3 is the third using time length, M 1 is the upper limit of corrosion defect depth of the corrosion layer, M 2 is the upper limit of corrosion defect strength of the corrosion layer, M 3 is the lower limit of yield stress, N 1 is the depth of corrosion defect of the corrosion layer corresponding to actual voltage, N 2 is the adhesion strength of the corrosion layer corresponding to actual voltage, N 3 is the yield stress corresponding to actual voltage, and determining the minimum using time length as the service life of the target long oil and gas pipeline in the first using time length, the second using time length and the third using time length of the target long oil and gas pipeline.
Wherein the upper limit of the corrosion defect depth of the anti-corrosion layer, the upper limit of the adhesion force of the anti-corrosion layer and the upper limit of the yield stress are respectively 0.025 millimeter/year, 140N/cm (unit: newton/cm) and 500MPa (unit: megapascal). If at least one of the corrosion defect depth of the corrosion prevention layer exceeds 0.025 mm/year, the adhesion force of the corrosion prevention layer exceeds 140N/cm or the yield stress is lower than 500MPa, the long oil and gas pipeline can be determined to be unable to continue to be used. For the specific service life of the long oil and gas pipeline, the method can be based on the formulaQuantitative calculation was performed.
The steps 201-205 are performed based on a set of experimental devices shown in fig. 1, and in a specific implementation, multiple sets of the devices can be further arranged to simulate the damage of interference voltage intensity of different high-voltage direct current transmission lines to the corrosion prevention layer of the long-distance oil and gas transmission pipeline, such as stripping, hydrogen embrittlement and corrosion of the pipe body.
For example, three experimental groups and one control group may be provided. The power output voltages of the three groups of experimental groups are 120V, 60V and 20V respectively and are used for simulating the interference voltage intensity of the high-voltage direct-current transmission line to be 120V, 60V and 20V respectively, and the control group is not provided with a power supply and is only provided with one experimental pipe section and is used for simulating the running state of a long oil and gas transmission pipeline without the interference voltage of the high-voltage direct-current transmission line. The experimental pipe sections used in the experimental group and the control group are 2m long, the inner radius of the pipe is 416 mm, the wall thickness of the pipe is 6mm, the surface of the pipe section is provided with a common-level three-layer PE (polyethylene) anti-corrosion layer (anti-corrosion layer) with the same shape and the same area on the same clock direction of the outer wall of the pipe section, the specific detection process is similar to the processing of the steps 201-205, and the detailed description is omitted here.
In particular, since the soil resistivity directly affects the magnitude of the disturbing voltage of the hvdc transmission line received by the experimental apparatus, it is necessary to measure the soil resistivity in order to eliminate the experimental error. For example, a local soil sample of the embedded test tube segment may be collected and the soil resistivity of the sample measured using the wenna four electrode method.
The technical scheme provided by the embodiment of the application has the beneficial effects that:
The device is formed by an anode tube section 1, a cathode tube section 2, a plurality of long-acting reference electrodes 3, a test pile 4, a sacrificial anode 5, a power supply 6, a prestress bracket 7, a steel sample 8 and a plurality of wires, and the damage degree of stripping, hydrogen embrittlement and corrosion of a pipe body of an anticorrosive layer caused by interference voltage generated by a high-voltage direct-current transmission line in an actual scene to a long-term oil and gas pipeline is simulated. The copper sheets on the binding post 42, the binding post 43 and the binding post 46 are respectively connected with the binding post 40, the binding post 45 and the binding post 48, the output voltage of the power supply 6 is set to be the target voltage, after a preset unit time, namely after a short period, the corrosion defect depth of the corrosion layer of the anode pipe section 1, the adhesion force of the corrosion layer of the cathode pipe section and the yield stress of a steel sample are detected, the damage degree of corrosion, hydrogen embrittlement and peeling of the corrosion layer of the long oil and gas pipeline body can be obtained, and the service life of the long oil and gas pipeline is determined based on the preset upper limit of the corrosion defect depth of the corrosion layer, the preset upper limit of the adhesion force of the corrosion layer, the preset lower limit of the yield stress and the corrosion defect depth of the corrosion layer, the adhesion force of the corrosion layer and the yield stress corresponding to the actual voltage, the detection period is shortened, and therefore the timeliness is good.
Any combination of the above optional solutions may be adopted to form an optional embodiment of the present application, which is not described herein.
The foregoing description of the preferred embodiments of the application is not intended to limit the application to the precise form disclosed, and any such modifications, equivalents, and alternatives falling within the spirit and scope of the application are intended to be included within the scope of the application.
Claims (10)
1. A method of determining the service life of a long oil and gas pipeline, the method being applied to a device for determining the service life of a long oil and gas pipeline, the device for determining the service life of a long oil and gas pipeline comprising: the device comprises an anode tube section 1, a cathode tube section 2, a plurality of long-acting reference electrodes 3, a test pile 4, a sacrificial anode 5, a power supply 6, a pre-stress bracket 7, a steel sample 8 and a plurality of wires, wherein the pre-stress bracket 7 comprises a loading bolt 70, a frame 71 and a fixing bolt 72, the steel sample 8 is fixed on the frame 71 through the loading bolt 70 and the fixing bolt 72, the loading bolt 70 is used for applying preset stress to the steel sample 8, the anode tube section 1 and the cathode tube section 2 are long oil and gas pipeline samples, the steel sample 8 is a slice of the long oil and gas pipeline samples, the surfaces of the anode tube section 1 and the cathode tube section 2 are provided with preset corrosion-resistant layer defects, the anode tube section 1 and the cathode tube section 2 are arranged in parallel in the horizontal direction at a first preset distance and are buried in the ground of a preset depth, a long-acting reference electrode 3 is arranged at a second preset distance between the anode tube section 1 and the cathode tube section 2, the test pile 4 comprises a base 410 and a binding post 40, a binding post 41, a binding post 42, a binding post 43, a binding post 44, a binding post 45, a binding post 46, a binding post 47, a binding post 48 and a binding post 49 which are arranged on the base 410, copper sheets which are freely rotated are arranged on the binding post 42, the binding post 43 and the binding post 46, the anode tube section 1 is connected with the binding post 40 and the binding post 43 respectively through wires, the cathode tube section 2 is connected with the binding post 48 and the binding post 45 respectively through wires, the positive electrode of a power supply 6 is connected with the binding post 42, the negative electrode of the power supply 6 is connected with the binding post 46, one long-acting reference electrode 3 is connected with the binding post 41 through wires, the other long-acting reference electrode 3 is connected with the binding post 49 through wires, and a steel sample 8 is connected with the binding post 48 through wires, and the method comprises:
Connecting the copper piece on the binding post 42 with the binding post 40, connecting the copper piece on the binding post 46 with the binding post 48, connecting the copper piece on the binding post 43 with the binding post 45, and setting the output voltage of the power supply 6 to be a target voltage;
after a preset unit time length, detecting the corrosion defect depth of the corrosion layer of the anode tube section 1, the adhesion force of the corrosion layer of the cathode tube section 2 and the yield stress of the steel sample 8;
Adding the target voltage, the corrosion defect depth of the corrosion protection layer, the adhesion force of the corrosion protection layer and the yield stress into the pre-established corresponding relation of the voltage, the corrosion defect depth of the corrosion protection layer, the adhesion force of the corrosion protection layer and the yield stress;
Detecting the actual voltage of a target long-distance oil and gas pipeline, and determining the corrosion defect depth, the adhesion force of the corrosion layer and the yield stress of the corrosion layer corresponding to the actual voltage based on the corresponding relation;
And determining the service life of the target long oil and gas pipeline based on the preset upper limit of corrosion defect depth of the corrosion layer, the preset upper limit of adhesion force of the corrosion layer and the preset lower limit of yield stress, and the corrosion defect depth of the corrosion layer, the adhesion force of the corrosion layer and the preset yield stress corresponding to the actual voltage.
2. The method of claim 1, wherein the post 47 is provided with a copper piece, the method further comprising, before connecting the copper piece on the post 42 to the post 40, connecting the copper piece on the post 46 to the post 48, disconnecting the copper piece on the post 47 from the post 45, and setting the output voltage of the power supply 6 to the target voltage:
disconnecting the copper sheet on the binding post 42 from the binding post 40, disconnecting the copper sheet on the binding post 46 from the binding post 48, and connecting the copper sheet on the binding post 47 with the binding post 45;
Detecting a voltage between the terminal 45 and the terminal 47, determining that the voltage is less than a preset voltage threshold;
When the copper piece on the post 42 is connected to the post 40, the copper piece on the post 46 is connected to the post 48, the copper piece on the post 43 is connected to the post 45, and the output voltage of the power supply 6 is set to the target voltage, the copper piece on the post 47 is disconnected from the post 45.
3. The method according to claim 1, characterized in that both ends of the anode pipe section 1 are provided with hard caps and both ends of the anode pipe section 2 are provided with hard caps.
4. The method of claim 1, wherein the long-acting reference electrode 3 is a long-acting copper sulfate reference electrode.
5. The method according to claim 1, wherein the test stake 4 is provided at an intermediate position of the anode tube section 1 and the cathode tube section 2.
6. The method of claim 1, wherein the sacrificial anode 5 is a pre-packaged magnesium anode.
7. The method according to claim 1, wherein the sacrificial anode 5 is buried in the anode segment 1 at a position intermediate to the cathode segment 2.
8. The method of claim 1, wherein the power source 6 is a lithium battery.
9. The method according to claim 1, characterized in that an insulating spacer is arranged between the steel sample 8 and the loading bolt 70.
10. The method of claim 1, wherein determining the target long life of the oil and gas pipe based on the preset upper limit of corrosion defect depth of the corrosion layer, the upper limit of adhesion of the corrosion layer, the lower limit of yield stress, and the corresponding corrosion defect depth of the corrosion layer, adhesion of the corrosion layer, and yield stress of the actual voltage comprises:
based on a preset corrosion defect depth upper limit, a corrosion resistance adhesion upper limit, a yield stress lower limit and a formula of the corrosion resistance Respectively obtaining a first using time length, a second using time length and a third using time length of the target long oil and gas pipeline, wherein/>For the first duration of use,/>For the second duration of use,/>For the third duration of use,Is the upper limit of the depth of corrosion defect of the anticorrosive coating,/>Is the upper limit of the adhesive force of the anticorrosive coating,/>Is the lower limit of yield stress,/>For the corrosion defect depth of the corrosion-resistant layer corresponding to the actual voltage,/>Is the adhesive force of the anti-corrosion layer corresponding to the actual voltage,/>Yield stress corresponding to actual voltage;
And determining the minimum use time length as the service life of the target long oil and gas transmission pipe in the first use time length, the second use time length and the third use time length of the target long oil and gas transmission pipe.
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| CN103411878A (en) * | 2013-07-13 | 2013-11-27 | 北京工业大学 | Method for stray current corrosion test of buried steel pipeline under tensile stress action |
| CN104005032A (en) * | 2014-05-08 | 2014-08-27 | 青岛双瑞海洋环境工程股份有限公司 | Cathode protection test probe of prestressed steel cylinder concrete pipe and preparation method thereof |
| CN105586596A (en) * | 2016-03-28 | 2016-05-18 | 沈阳龙昌管道检测中心 | Pipeline corrosion and protection experiment system |
| CN205635783U (en) * | 2016-03-28 | 2016-10-12 | 沈阳龙昌管道检测中心 | Pipeline corrosion control system tests junction box |
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| CN103411878A (en) * | 2013-07-13 | 2013-11-27 | 北京工业大学 | Method for stray current corrosion test of buried steel pipeline under tensile stress action |
| CN104005032A (en) * | 2014-05-08 | 2014-08-27 | 青岛双瑞海洋环境工程股份有限公司 | Cathode protection test probe of prestressed steel cylinder concrete pipe and preparation method thereof |
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| CN205635783U (en) * | 2016-03-28 | 2016-10-12 | 沈阳龙昌管道检测中心 | Pipeline corrosion control system tests junction box |
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