System and method for detection of carburization on the pyrolysis furnace tube using magnetic permeability

Abstract

The present invention relates to a system for measuring carburization of a pyrolysis tube using permeability. More specifically, the invention relates to a technology that can determine the deterioration state of a pyrolysis tube in advance by measuring the degree of carburization of the pyrolysis tube using the relationship between the change in permeability caused by the change in the magnetic phase of the material of the pyrolysis tube as carburization proceeds inside the pyrolysis tube.

Description

Technology Field

[0001] The present invention relates to a system and method for measuring carburization of a pyrolysis tube using permeability, and more specifically, to a system and method for measuring carburization of a pyrolysis tube using permeability capable of evaluating the degree of carburization penetrating from the inner wall of the pyrolysis tube into the tissue of the pyrolysis tube. Background Technology

[0002] In an ethylene pyrolysis furnace, raw materials such as naphtha and ethane are introduced through a pyrolysis furnace tube into a furnace heated to 1,000 to 1,200°C, and a decomposition reaction takes place at the outlet temperature of the pyrolysis furnace tube (800 to 850°C). During this decomposition process, solid carbon (coke) is generated and deposited. Due to this process (coking), the deposited carbon undergoes a carburization phenomenon in which it penetrates from the inner wall of the pyrolysis furnace into the structure of the furnace. Carburization alters the alloy structure of the pyrolysis furnace material, causing volume expansion, a decrease in the coefficient of thermal expansion, and embrittlement of the material, which significantly affects the lifespan of the pyrolysis furnace. Accordingly, it is necessary to accurately measure the degree of carburization to inspect the deterioration state of the pyrolysis furnace and prevent damage in advance.

[0003] To this end, applicable conventional non-destructive testing methods include radiographic testing (RT), ultrasonic testing (UT), penetrant testing (PT), and eddy current testing (ECT). However, these testing methods have the disadvantage that the signals are often ambiguous, making them unsuitable for detecting the carburized layer of the pyrolysis tube. Additionally, a method was developed to contact a permanent magnet with the pyrolysis tube and measure the resulting magnetic field, but a problem arose where magnetic foreign substances adhered to the permanent magnet during the application process.

[0004] In addition, Korean registered patent No. 10-0696991 ("Apparatus and method for detecting eddy currents of steam generator heat transfer tubes using permeability measurement method") discloses a technology that identifies the characteristics of a material according to a magnetic phase that causes errors in signal interpretation regarding axial defects as well as axial defects of steam generator heat transfer tubes, thereby eliminating the cause of signal errors and rapidly, accurately, and conveniently detecting information on circumferential defects that were difficult to detect. Prior art literature

[0005] Korean Registered Patent No. 10-0696991 (Registration Date: March 13, 2007) The problem to be solved

[0006] Accordingly, the present invention has been devised to solve the problems of the prior art as described above, and the objective of the present invention is to provide a system and method for measuring the carburization of a pyrolysis tube using permeability capable of measuring the degree of carburization of a pyrolysis tube in the petrochemical industry.

[0007] In particular, the invention provides a system and method for measuring carburization of a pyrolysis tube using permeability, which can identify the deterioration state of a pyrolysis tube in advance by measuring the degree of carburization of the pyrolysis tube by utilizing the relationship between the change in permeability due to the change in the magnetic phase of the material of the pyrolysis tube as carburization proceeds inside the pyrolysis tube. means of solving the problem

[0008] The carburization measurement system of a pyrolysis tube using permeability according to the present invention for achieving the above-mentioned purpose preferably comprises a probe portion positioned to contact the outer surface of a specimen, an analysis portion that analyzes the permeability of the specimen using the magnetic properties of the specimen output by the probe portion, and a measurement portion that measures the degree of carburization of the specimen by comparing a preset reference value with the permeability analyzed by the analysis portion.

[0009] Furthermore, it is preferable that the probe comprises a core designed in a yoke shape, a power application coil wound axially on one leg of the core, a B-field measuring coil wound axially on the other leg of the core, and an H-field measuring coil disposed between the cores.

[0010] Furthermore, it is preferable that the H-field measuring coil be positioned at the x-axis center of the core and arranged so that one side contacts the outer surface of the specimen.

[0011] Furthermore, it is preferable that the analysis unit is supplied with power from the outside through the power application coil, measures the magnetic flux density (B) by integrating the electromotive force induced in the B-field measurement coil according to the power supplied by the power application coil, and measures the magnetic field strength (H) by integrating the electromotive force induced in the H-field measurement coil according to the power supplied by the power application coil.

[0012] Furthermore, it is desirable for the analysis unit to analyze the permeability using the measured magnetic flux density and magnetic field strength.

[0013] Furthermore, the analysis unit preferably analyzes a measurement signal by using the measured magnetic flux density to output only signals that have the same phase as the measured frequency through a low-frequency band filter, and analyzes the permeability using the measured magnetic flux density and the analyzed measurement signal.

[0014] In addition, the above measuring unit compares the pre-set reference value with the permeability analyzed by the above analysis unit, and if the analyzed permeability exceeds the pre-set reference value, it is determined that carburization of the specimen has occurred, and it is desirable to measure the degree of carburization of the specimen according to the degree of excess.

[0015] The method for measuring carburization of a pyrolysis tube using permeability according to the present invention for achieving the above-mentioned purpose preferably includes an analysis step (S100) in which, in an analysis unit, the magnetic properties of a specimen output by a probe are measured and the permeability of the specimen is analyzed using the results, and a measurement step (S200) in which, in a measurement unit, a preset reference value is compared with the permeability obtained from the analysis step (S100), and if the permeability exceeds the preset reference value, it is determined that a carburization phenomenon has occurred in the specimen, and the degree of carburization of the specimen is measured according to the degree of excess.

[0016] Furthermore, in the above measurement step (S100), power is supplied from the outside through a power application coil wound axially on one leg of a core designed in a yoke shape, and the magnetic flux density (B) is measured by integrating the electromotive force induced according to the power supplied by the power application coil into a B-field measurement coil wound axially on one leg of the core, and the magnetic field strength (H) is measured by integrating the electromotive force induced according to the power supplied by the power application coil into an H-field measurement coil disposed between the cores.

[0017] In addition, the above analysis step (S100) preferably analyzes the permeability using the measured magnetic flux density and magnetic field strength.

[0018] In addition, the above analysis step (S100) preferably analyzes a measurement signal that outputs only signals with the same phase as the measured frequency through a low-frequency band filter using the measured magnetic flux density, and analyzes the permeability using the measured magnetic flux density and the analyzed measurement signal. Effects of the invention

[0019] A system and method for measuring carburization of a pyrolysis tube using permeability according to one embodiment of the present invention has the advantage of being able to identify the deterioration state of a pyrolysis tube in advance by measuring the degree of carburization of the pyrolysis tube using the relationship between the change in permeability caused by the change in the magnetic phase of the material of the pyrolysis tube as carburization proceeds inside the pyrolysis tube of a pyrolysis furnace operated in the petrochemical industry. Through this, there is an advantage of being able to prevent damage to the pyrolysis tube in advance. Brief explanation of the drawing

[0020] FIG. 1 is an exemplary diagram showing a pyrolysis tube to which a carburization measurement system using permeability according to one embodiment of the present invention is applied. FIG. 2 is an exemplary configuration diagram showing a carburization measurement system of a pyrolysis tube using permeability according to one embodiment of the present invention. FIG. 3 is an exemplary diagram showing the change in signal magnitude for the Lift-off of the probe part of a carburization measurement system of a pyrolysis tube using permeability according to one embodiment of the present invention. FIG. 4 is a flowchart illustrating a method for measuring carburization of a pyrolysis tube using permeability according to one embodiment of the present invention. Specific details for implementing the invention

[0021] Hereinafter, a system for measuring carburization of a pyrolysis tube using permeability and a method thereof, having the configuration as described above according to the present invention, will be explained in detail with reference to the attached drawings. The drawings presented below are provided as examples to ensure that the concept of the present invention is sufficiently conveyed to those skilled in the art. Accordingly, the present invention is not limited to the drawings presented below and may be embodied in other forms. In addition, throughout the specification, the same reference numerals indicate the same components.

[0022] Unless otherwise defined, technical and scientific terms used herein have the meaning commonly understood by those skilled in the art to which this invention pertains, and descriptions of known functions and configurations that could unnecessarily obscure the essence of the invention are omitted in the following description and accompanying drawings.

[0023] Furthermore, a system refers to a set of components, including devices, mechanisms, and means, that are organized and interact regularly to perform necessary functions.

[0024] A system and method for measuring carburization of a pyrolysis tube using permeability according to one embodiment of the present invention relates to a technology that evaluates the degree of carburization through permeability by measuring the permeability of a pyrolysis tube material, based on the fact that as the pyrolysis tube is used, it combines with penetrating carbon to form carbides, and thus the tube material structure around the carbides changes from paramagnetic to ferromagnetic due to a significant decrease in chromium (Cr) content and a relative increase in nickel (Ni) content.

[0025] Simply put, the system and method for measuring carburization of a pyrolysis tube using permeability according to one embodiment of the present invention comprises a probe including a yoked core positioned perpendicular to the axial direction of the pyrolysis tube to obtain detection information regarding the degree of carburization of the pyrolysis tube, that is, the amount of change in magnetic properties according to the degree of carburization of the pyrolysis tube, and thereby detect the degree of carburization of the pyrolysis tube (specimen).

[0026] FIG. 1 is an exemplary diagram showing a pyrolysis tube to which a carburization measurement system for a pyrolysis tube using permeability according to one embodiment of the present invention is applied, and FIG. 2 is an exemplary diagram showing the configuration of a carburization measurement system for a pyrolysis tube using permeability according to one embodiment of the present invention. As shown in FIG. 1 and FIG. 2, the system includes a probe (10), an analysis unit (20), and a measurement unit (30). The probe (10) is positioned to contact the outer surface of a specimen (pyrolysis tube), and the analysis unit and the measurement unit (30) are connected to the probe (10) and perform operations in a computational processing means including a computer that analyzes transmitted data.

[0027] If we take a closer look at each component,

[0028] The probe (10) is positioned to contact the outer surface of a specimen and includes a core (11) designed in a yoke shape. Additionally, it is preferable to include a power application coil (12) wound axially around one leg of the core (11), a B-field measurement coil (13) wound axially around the other leg of the core (11), and an H-field measurement coil (14) positioned between the core (11).

[0029] At this time, it is preferable that the H-field measuring coil (14) be positioned at the x-axis center of the core (11) as shown in FIGS. 1 and 2, and that one side be positioned so as to be in contact with the outer surface of the specimen.

[0030] Generally, the method for measuring the magnetic properties of a specimen involves forming a magnetic closed circuit by magnetizing the specimen using a yoke. Specifically, when the demagnetization factor of the specimen is zero, the magnetic hysteresis properties of the specimen can be measured by directly winding a coil on the specimen to measure the magnetizing force (H) from the current flowing through the primary coil (power application coil), and calculating the magnetic flux density (B) from Faraday's law (Faraday's law of electromagnetic induction) by integrating the electromotive force induced in the secondary coil (B-field measurement coil). However, in most cases, the size of the specimen is finite, making it practically impossible to measure magnetic properties due to the demagnetization effect. Furthermore, as a non-contact method for measuring the magnetic properties of a specimen, it is common to form a magnetic closed circuit by magnetizing the specimen using a yoke. Through this, the magnetizing force is measured from the current flowing through the primary coil, and the magnetic flux of the yoke is measured to determine the magnetic flux density of the specimen (pyrolysis tube). However, in this case, if the size of the magnetic phase is small, there is a problem in that it is difficult to separate only the magnetic phase.

[0031] Accordingly, in the present invention, it is preferable to configure an H-field measuring coil (14) that includes an H-search coil (detection coil, potential coil) rather than a primary coil to measure magnetization force, as in the probe (10). Through this, the magnetization force can be measured by integrating the electromotive force induced in the H-field measuring coil. Of course, an integrator is required to measure magnetization force, but compared to conventional methods, it has the advantage of being less affected when the gap between the specimen and the yoke, i.e., the lift-off, changes.

[0032] It is preferable to manufacture the core (11) by laminating non-oriented silicon steel sheets of a certain thickness, molding them, and then wire cutting. Based on various experimental results, it is preferable to increase the spacing between the legs of the core (11) to 5.5 mm in order to place the H-field measuring coil (14) between the legs (one leg and the other leg) of the core (11). Additionally, the power application coil (12) and the B-field measuring coil (13), which are each wound on the legs of the manufactured core (11), are composed of enameled copper wire. It is preferable to use enameled copper wire with a diameter of 0.15 mΦ for the windings of the power application coil (12) and the B-field measuring coil (13), and to wind each 100 times. In addition, it is most preferable to construct the above H-field measuring coil (14) by winding an enameled copper wire with a diameter of 0.1 mΦ 100 times on an epoxy plate with a thickness of 0.5 m and a width of 4 m.

[0033] As a result of various experiments, when measuring the change in probe signal magnitude with respect to lift-off using a probe configured with the H-field measuring coil (14) as in the probe part (10) of the present invention, it can be seen that the probe signal magnitude tends to decrease with lift-off, as shown in FIG. 3a). This is similar to a primary coil current type probe. However, when comparing this, that is, comparing a probe configured with the H-field measuring coil (14) as in the probe part (10) of the present invention with a conventional probe (primary coil current type probe), and measuring the change in probe signal magnitude, as shown in FIG. 3b), the H-search coil type probe has a smaller rate of decrease in probe signal magnitude with respect to lift-off, so when lift-off changes, the effect is smaller, and it can be seen that it is more effective in reducing signal reduction.

[0034] When power is supplied to the power supply coil (12) from the outside, the analysis unit (20) measures the magnetic flux density (B) by integrating the electromotive force induced in the B-field measurement coil (13) according to the power supplied by the power supply coil (12). Additionally, the magnetic field strength (H) is measured by integrating the electromotive force induced in the H-field measurement coil (14) according to the power supplied by the power supply coil (12).

[0035] To explain in detail the measurement of magnetic flux density, the electromotive force induced in the B-field measuring coil (13) according to the power supplied by the power application coil (12) is integrated using an integrator (Int). Afterwards, in order to compensate for air magnetic flux, the magnitude of the magnetizing force signal is adjusted and combined with a signal whose phase has been shifted by 180° to produce an output. The output signal is converted from an analog signal to a digital signal through an ADC (Analog-Digital Converter) and then transmitted to the measuring unit (30). At this time, the magnitude of the magnetizing force signal is adjusted so that the magnetic flux density output voltage becomes 0 when the specimen does not have a magnetic phase.

[0036] To explain in detail the measurement of magnetic field strength, it can be obtained by integrating the electromotive force induced in the H-field measurement coil (14). The coil signal output by the H-field measurement coil (14) is compensated by passing it through an air-flux compensator, and then integrated through an integrator. Afterward, it is amplified by passing it through an amplifier, and then each phase is separated in a Lick-in Amp, and only the low-frequency components are passed through a Low-Pass Filter (LPF). After converting the analog signal into a digital signal through such an Analog-Digital Converter (ADC), it is processed through a preset operation and transmitted to the measurement unit (30).

[0037] The analysis unit (20) and the measurement unit (30) are preferably configured in an external flaw detector, and when measuring changes in magnetic flux, it is preferable to use an RS-422 serial communication medium to prevent signal distortion and reduce noise, and to transmit only the acquired electrical signal. Of course, this is merely one embodiment of the present invention, and various communication media may be used.

[0038] The above analysis unit (20) analyzes the permeability using the measured magnetic flux density and magnetic field strength. The relationship between the magnetic flux density (B) and the magnetic field strength (H) is B = μH. Here, μ represents permeability. Permeability refers to the degree to which a material becomes magnetized, or magnetized, when placed in a magnetic field, and the higher the permeability, the greater the magnetic flux density.

[0039] At this time, a method of measuring and analyzing all BH signals is proposed to detect the magnetic phase portion under various conditions as described above. However, since most of the ferromagnetic phases appear as a magnetic flux density with air flux compensated, the analysis unit (20) converts the measured magnetic flux density into a DC signal and uses it. Specifically, using the measured magnetic flux density, the measurement signal that outputs only the signal with the same phase as the measured frequency through a low-frequency band filter is used as the DC signal.

[0040] In this case, the analysis unit (20) analyzes the permeability using the measured magnetic flux density and the analyzed measurement signal.

[0041] It is preferable for the measuring unit (30) to measure the degree of carburization of the specimen by comparing a preset reference value with the permeability analyzed by the analysis unit (20). Specifically, it is preferable for the measuring unit (30) to compare a preset reference value with the permeability analyzed by the analysis unit (20), and to determine that a carburization phenomenon has occurred in the specimen if the analyzed permeability exceeds the preset reference value. Additionally, the degree of carburization of the specimen is measured according to the degree of excess of the analyzed permeability.

[0042] Here, it is preferable that the preset reference value be μ > 10 to 100. Since the non-magnetic material itself has μ of 1, it is acceptable if it is 1 or greater, but for the reliability of the measurement, it is preferable to set the reference value to 10 to 100.

[0043] FIG. 4 is a flowchart illustrating a method for measuring carburization of a pyrolysis tube using permeability according to an embodiment of the present invention. As shown in FIG. 4, the method includes an analysis step (S100) and a measurement step (S200). The above steps are operated by a computational processing means that performs a system for measuring carburization of a pyrolysis tube using permeability according to an embodiment of the present invention.

[0044] Let's take a closer look at each step.

[0045] The above analysis step (S100) measures the magnetic properties of the specimen output by the probe in the analysis unit (20) and uses this to analyze the permeability of the specimen.

[0046] Here, the probe (10) is positioned to contact the outer surface of the specimen and includes a core (11) designed in a yoke shape. Additionally, it is preferable to include a power application coil (12) wound axially on one leg of the core (11), a B-field measurement coil (13) wound axially on the other leg of the core (11), and an H-field measurement coil (14) positioned between the core (11).

[0047] At this time, it is preferable that the H-field measuring coil (14) be positioned at the x-axis center of the core (11) as shown in FIG. 1, and that one side be positioned so as to be in contact with the outer surface of the specimen.

[0048] Generally, the method for measuring the magnetic properties of a specimen involves forming a magnetic closed circuit by magnetizing the specimen using a yoke. Specifically, the magnetization force (H) is measured from the current flowing through the primary coil (power application coil), and the magnetic flux of the yoke is measured in the secondary coil (B-field measurement coil) to measure the magnetic flux density of the pyrolysis tube. However, in this case, if the size of the magnetic phase is small, there is a problem in that it is difficult to separate only the magnetic phase.

[0049] Accordingly, in the present invention, it is preferable to configure an H-field measuring coil (14) that includes an H-search coil (detection coil, potential coil) rather than a primary coil to measure magnetization force, as in the probe (10). Through this, the magnetization force can be measured by integrating the electromotive force induced in the H-field measuring coil. Of course, an integrator is required to measure magnetization force, but compared to conventional methods, it has the advantage of being less affected when the gap between the specimen and the yoke, i.e., the lift-off, changes.

[0050] It is preferable to manufacture the core (11) by laminating non-oriented silicon steel sheets of a certain thickness, molding them, and then wire cutting. Based on various experimental results, it is preferable to increase the spacing between the legs of the core (11) to 5.5 mm in order to place the H-field measuring coil (14) between the legs (one leg and the other leg) of the core (11). Additionally, the power application coil (12) and the B-field measuring coil (13), which are each wound on the legs of the manufactured core (11), are composed of enameled copper wire. It is preferable to use enameled copper wire with a diameter of 0.15 mΦ for the windings of the power application coil (12) and the B-field measuring coil (13), and to wind each 100 times. In addition, it is most preferable to construct the above H-field measuring coil (14) by winding an enameled copper wire with a diameter of 0.1 mΦ 100 times on an epoxy plate with a thickness of 0.5 m and a width of 4 m.

[0051] In the above analysis step (S100), when power is supplied to the power supply coil (12) from the outside, the electromotive force induced in the B-field measuring coil (13) according to the power supplied by the power supply coil (12) is integrated to measure the magnetic flux density (B). Additionally, the electromotive force induced in the H-field measuring coil (14) according to the power supplied by the power supply coil (12) is integrated to measure the magnetic field strength (H).

[0052] To explain in detail the measurement of magnetic flux density, the electromotive force induced in the B-field measuring coil (13) according to the power supplied by the power application coil (12) is integrated using an integrator (Int). Afterwards, in order to compensate for air magnetic flux, the magnitude of the magnetizing force signal is adjusted and combined with a signal whose phase has been shifted by 180° to produce an output. The output signal is converted from an analog signal to a digital signal through an ADC (Analog-Digital Converter) and then transmitted to the measuring unit (30). At this time, the magnitude of the magnetizing force signal is adjusted so that the magnetic flux density output voltage becomes 0 when the specimen does not have a magnetic phase.

[0053] To explain in detail the measurement of magnetic field strength, it can be obtained by integrating the electromotive force induced in the H-field measuring coil (14). Referring to FIG. 3, the coil signal output by the H-field measuring coil (14) is compensated by passing it through an air-flux compensator, and then integrated through an integrator. Afterward, it is amplified by passing it through an amplifier, and then each phase is separated in a Lick-in Amp, and only the low-frequency components are passed through a Low-Pass Filter (LPF). After converting the analog signal into a digital signal through such an ADC (Analog-Digital Converter), it is processed through a preset operation and transmitted to the measuring unit (30).

[0054] The above analysis step (S100) analyzes the permeability using the measured magnetic flux density and magnetic field strength. The relationship between the magnetic flux density (B) and the magnetic field strength (H) is given by B = μH. Here, μ represents permeability. Permeability refers to the degree to which a material becomes magnetized, or magnetic, when placed in a magnetic field; the higher the permeability, the greater the magnetic flux density.

[0055] At this time, a method of measuring and analyzing all BH signals was proposed to detect the region with a magnetic phase under various conditions, as described above. However, since most ferromagnetic phases appear as magnetic flux density compensated for by air flux, the analysis step (S100) converts the measured magnetic flux density into a DC signal and uses it. Specifically, using the measured magnetic flux density, the measurement signal is used as the DC signal by outputting only the signal that has the same phase as the frequency being measured through a low-frequency band filter. In this case, the analysis step (S100) analyzes the permeability using the measured magnetic flux density and the analyzed measurement signal.

[0056] The above measurement step (S200) compares the permeability determined by the analysis step (S100) with a preset reference value in the measurement unit (30), and if the permeability exceeds the preset reference value, it is determined that a carburization phenomenon has occurred in the specimen, and the degree of carburization of the specimen is measured according to the degree of excess.

[0057] Here, it is preferable that the preset reference value be μ > 10 to 100. Since the non-magnetic material itself has μ of 1, it is acceptable if it is 1 or greater, but for the reliability of the measurement, it is preferable to set the reference value to 10 to 100.

[0058] Meanwhile, in one embodiment of the present invention, a method for measuring carburization of a pyrolysis tube using permeability may be implemented in the form of program instructions that can be executed through various means of electronically processing information and recorded on a storage medium. The storage medium may include program instructions, data files, data structures, etc., either individually or in combination.

[0059] Program instructions recorded on a storage medium may be those specifically designed and configured for the present invention, or they may be those known and available to those skilled in the art of software. Examples of storage media include magnetic media such as hard disks, floppy disks, and magnetic tapes; optical media such as CD-ROMs and DVDs; magneto-optical media such as floptical disks; and hardware devices specifically configured to store and execute program instructions, such as ROM, RAM, and flash memory. Examples of program instructions include machine code, such as that generated by a compiler, as well as high-level language code that can be executed by a device that processes information electronically using an interpreter, such as a computer.

[0060] As described above, the present invention has been explained with specific details such as specific constituent elements and limited exemplary drawings; however, this is provided merely to aid in a more comprehensive understanding of the invention, and the invention is not limited to the above-mentioned embodiment. A person skilled in the art can make various modifications and variations from this description.

[0061] Accordingly, the scope of the present invention should not be limited to the described embodiments, and all things equivalent to or having equivalent variations to the claims set forth below, as well as the claims set forth below, shall be considered to fall within the scope of the concept of the present invention. Explanation of the symbols

[0062] 10: Probe 11 : Core 12: Power application coil 13: B-field measuring coil 14: H-field measuring coil

Claims

Claim 1 A carburization measurement system for a pyrolysis tube using permeability, comprising: a probe portion positioned to contact the outer surface of a specimen; an analysis portion that analyzes the permeability of the specimen using the magnetic properties of the specimen output by the probe portion; and a measurement portion that measures the degree of carburization of the specimen by comparing a preset reference value with the permeability analyzed by the analysis portion; wherein the probe portion comprises a core designed in a yoke shape; a power application coil wound axially around one leg of the core; a B-field measurement coil wound axially around the other leg of the core; and an H-field measurement coil positioned between the cores. Claim 2 delete Claim 3 A carburization measurement system for a pyrolysis tube using permeability according to claim 1, wherein the H-field measuring coil is positioned at the x-axis center of the core and arranged so that one surface contacts the outer surface of the specimen. Claim 4 A carburization measurement system for a pyrolysis tube using permeability, wherein the analysis unit is supplied with power from the outside through the power application coil, measures the magnetic flux density (B) by integrating the electromotive force induced in the B-field measurement coil according to the power supplied by the power application coil, and measures the magnetic field strength (H) by integrating the electromotive force induced in the H-field measurement coil according to the power supplied by the power application coil. Claim 5 In claim 4, the analysis unit analyzes permeability using the measured magnetic flux density and magnetic field strength, a carburization measurement system for a pyrolysis tube using permeability. Claim 6 In claim 4, the analysis unit analyzes a measurement signal that outputs only a signal having the same phase as the frequency to be measured through a low-frequency band filter using the measured magnetic flux density, in a carburization measurement system for a pyrolysis tube using permeability. Claim 7 In claim 6, the above analysis unit analyzes permeability using the measured magnetic flux density and the analyzed measurement signal, a carburization measurement system for a pyrolysis tube using permeability. Claim 8 A system for measuring carburization of a pyrolysis tube using permeability, wherein, in claim 5 or 7, the measuring unit compares a preset reference value with the permeability analyzed by the analysis unit, and if the analyzed permeability exceeds the preset reference value, determines that a carburization phenomenon has occurred in the specimen, and measures the degree of carburization of the specimen according to the degree of excess. Claim 9 Analysis step (S100) in which the magnetic properties of a specimen output by a probe in an analysis unit are measured, and the permeability of the specimen is analyzed using the same; A method for measuring carburization of a pyrolysis tube using permeability, comprising: a measurement step (S200) in which, in a measurement section, a preset reference value is compared with the permeability according to the analysis step (S100), and if the permeability exceeds the preset reference value, it is determined that a carburization phenomenon has occurred in the specimen, and the degree of carburization of the specimen is measured according to the degree of excess; wherein the analysis step (S100) supplies power from the outside through a power application coil wound axially on one leg of a core designed in a yoke shape, measures the magnetic flux density (B) by integrating the electromotive force induced according to the power supplied by the power application coil into a B-field measurement coil wound axially on one leg of the core, and measures the magnetic field strength (H) by integrating the electromotive force induced according to the power supplied by the power application coil into an H-field measurement coil disposed between the cores. Claim 10 delete Claim 11 In claim 9, the above analysis step (S100) is a method for measuring carburization of a pyrolysis tube using permeability, which analyzes permeability using measured magnetic flux density and magnetic field strength. Claim 12 In claim 9, the above analysis step (S100) analyzes a measurement signal that outputs only a signal with the same phase as the frequency to be measured through a low-frequency band filter using the measured magnetic flux density, and analyzes the permeability using the measured magnetic flux density and the analyzed measurement signal.

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