Disclosure of Invention
In order to solve the defects of the prior art, the invention aims to provide an electrode sounding system and an electrode sounding method for an electrode for a submerged arc furnace, which can effectively and accurately acquire the depth of the electrode in the submerged arc furnace without stopping production and submerged arc furnace or human intervention, thereby providing data basis for controlling the electrode, achieving the purposes of optimizing process operation, saving electric energy, improving product quality and reducing safety risk, and generating great social and economic benefits so as to overcome the defects in the prior art.
In order to achieve the above object, the present invention provides an electrode sounding system of an electrode for a submerged arc furnace, the electrode sounding system comprising a protection tube, a sensing rod, a transducer and an operation control device; the sensor rod is arranged in the protection tube, the protection tube and the sensor rod are embedded and communicated in the electrode for the submerged arc furnace together, the protection tube and the sensor rod can be synchronously consumed along with the electrode for the submerged arc furnace, and inert gas, nitrogen, carbon dioxide or mixed gas thereof is introduced into the protection tube; the transducer is positioned on the upper end face and/or the side face of the sensing rod and used for transmitting and/or receiving ultrasonic guided waves, and the ultrasonic guided waves are reflected at the end face of the sensing rod and transmitted along the sensing rod; the operation control device is electrically and signally connected with the transducer, and is used for acquiring the receiving time t and the speed v of ultrasonic guided wave transmission along the sensing rod through the transducer, calculating the total length H of the sensing rod according to the receiving time t of the ultrasonic guided wave and the speed v of the ultrasonic guided wave, and subtracting the length H of the electrode for the submerged arc furnace outside the submerged arc furnace from the total length H of the sensing rod to determine the depth D of the electrode for the submerged arc furnace in the submerged arc furnace.
According to the technical scheme, the sensing rod is reasonably arranged in the electrode for the submerged arc furnace, the ultrasonic guided wave is utilized to have the characteristic of reflecting at the end face of the sensing rod, the length of the sensing rod is obtained by measuring the transmission time of the reflected wave at the end face of the guided wave, meanwhile, the sensing rod can be used for consumption along with electrode consumption, namely, the length of the sensing rod is consistent with the length of the electrode, the length of the electrode and the depth of the electrode in the submerged arc furnace can be synchronously obtained, the defects of a measuring method for the depth of the electrode in the submerged arc furnace in the prior art, such as poor accuracy, incapability of continuously measuring, working condition and submerged arc furnace influence measurement, manual intervention and the like, are avoided, unexpected effects are obtained, and the depth of the electrode in the submerged arc furnace can be effectively and accurately obtained without stopping the submerged arc furnace or manual intervention, so that data basis is provided for the control electrode, and the purposes of optimizing technological operation, saving electric energy, improving product quality and reducing safety risks are achieved.
As a further explanation of the electrode sounding system of the electrode for a submerged arc furnace according to the present invention, it is preferable that the electrode for a submerged arc furnace includes a self-baking electrode, a graphite electrode and a carbon electrode.
As a further illustration of the electrode sounding system of the electrode for submerged arc furnaces according to the present invention, preferably the transducer is an electromagnetic ultrasonic transducer and/or a magnetostrictive transducer and/or a piezoelectric transducer.
As a further explanation of the electrode sounding system of the electrode for a submerged arc furnace according to the present invention, preferably, the melting point of the protection tube is above 2000 ℃, and the protection tube is made of one or more of a metal material, graphite and/or a ceramic material; the metal material is selected from one or more of tungsten, molybdenum, rhenium, iridium and lanthanum monomers and/or mixtures; the ceramic material is one or more of aluminum oxide, zirconium oxide, magnesium oxide, silicon carbide, molybdenum silicide, molybdenum carbide, titanium carbide monomer or mixture thereof, zirconium oxide or aluminum oxide aerogel and/or aerogel fiber.
Through the technical scheme, the inventor conducts multiple experimental researches, and the selected material of the protection tube has the advantage of synchronous consumption with the electrode for the submerged arc furnace, so that the length of the sensing rod arranged in the protection tube and the depth of the electrode for the submerged arc furnace in the submerged arc furnace are closely related, and the accuracy of electrode depth measurement is further ensured. Further, the metal material can be used for preventing the protection tube from being crushed by the spherical electrode paste, and meanwhile, the graphite material also has the function of preventing the paste electrode paste from corroding the protection tube, and the graphite material can be used for supporting the lower end part of the protection tube, so that the protection tube is kept smooth at high temperature and prevented from being blocked by molten metal of the metal tube. The ceramic material can be used for preventing the sensing rod from being chemically reacted with graphite at high temperature to lead to the purpose of premature fusing. The protective tube is in a regular and/or irregular tubular shape, including but not limited to one or more of square tube, round tube, oval tube, polygonal tube, irregularly shaped tube.
As a further explanation of the electrode sounding system of the electrode for the submerged arc furnace according to the present invention, preferably, the melting point of the sensing rod is above 2000 ℃, and the sensing rod is made of one or more of metal materials, graphite and/or ceramic materials; the metal material is selected from one or more of tungsten, molybdenum, rhenium, iridium and lanthanum monomers and/or mixtures; the ceramic material is selected from one or more of aluminum oxide, zirconium oxide, magnesium oxide, silicon carbide, and monomer and/or mixture of molybdenum silicide.
Through the technical scheme, through repeated experimental researches of the inventor, the material of the selected sensing rod can ensure that the sensing rod has good ultrasonic guided wave transmission and reflection performance, so that the problem that the sensing rod melts in an electrode for an submerged arc furnace, so that ultrasonic guided waves are absorbed and reflected waves are difficult to form is avoided; on the other hand, the high-temperature easily-oxidized material is adopted, so that the part of the sensing rod beyond the electrode end can be oxidized by furnace gas at high temperature, the consumption of the sensing rod together with the electrode for the submerged arc furnace is realized, the purpose of indicating the position of the electrode is achieved, and the accuracy of electrode depth measurement in the submerged arc furnace is ensured.
As a further explanation of the electrode sounding system of the electrode for the submerged arc furnace according to the present invention, preferably, the sensing rod has a melting point of 2200 ℃ or higher, and the sensing rod is made of one or more of graphite, alumina, zirconia, magnesia, tungsten, molybdenum monomers and/or mixtures.
By the technical scheme, the sensing rod with the melting point higher than 2000 ℃ and preferably 2200 ℃ is placed in the through hole, and when the sensing rod passes through the middle hole of the electrode, the sensing rod reaches the position of the interface between the lower end face of the electrode and the cavity, and the protruding part is rapidly melted and oxidized. When the electrode is gradually consumed, the sensing rod can realize synchronous consumption along with the electrode in the submerged arc furnace, at the moment, the length of the sensing rod represents the length of the electrode, and the depth of the electrode inserted into the furnace can be calculated by measuring the length of the sensing rod and the depth of the electrode outside the furnace.
As a further explanation of the electrode sounding system of the electrode for the submerged arc furnace according to the present invention, preferably, the sensor rod is provided with a groove or a protrusion at intervals of Δl for reflecting the ultrasonic guided wave; the groove or the protrusion closest to the lower end surface of the sensing rod is the nth groove or protrusion, and the distance from the groove or the protrusion to the lower end surface of the sensing rod is S, S < delta L; the ultrasonic guided waves are transmitted along the sensing rod, and each groove generates reflected waves; the total length H of the sensing rod is as follows:
(1) The distance from the top end of the sensing rod to the lowest groove or protrusion is as follows: n×Δl;
(2) The nth groove or protrusion of the sensing rod is spaced from the lower section of the sensing rod
The total length of the sensing rod
Wherein,the average speed of the lower end of the ultrasonic guided wave is; ts is the receiving time of the reflected wave of the lower end face of the sensing rod; tn is the receiving time of the reflected wave of the nth groove or protrusion;
(3) The depth D=H-H of the electrode for the submerged arc furnace in the submerged arc furnace;
the distance between the lower end part of the electrode for the submerged arc furnace and the furnace bottom is as follows: d=l-D;
wherein H is the total length of the sensing rod; h is the length of the electrode outside the submerged arc furnace, and is obtained through measurement; l is the total depth of the submerged arc furnace; s, H and delta L, h, D, d, L units are rice (m); ts and tn are each seconds(s);in meters per second (m/s).
As a further explanation of the electrode sounding system of the electrode for the submerged arc furnace according to the present invention, preferably, the operation control device includes an operation control module electrically connected and signal-connected with the high-power ultrasonic excitation module, the high-power ultrasonic excitation module electrically connected and signal-connected with the sensor matching circuit, the sensor matching circuit electrically connected and signal-connected with the transducer and the band-pass filter circuit, the band-pass filter circuit electrically connected and signal-connected with the gain adjustment circuit, the gain adjustment circuit electrically connected and signal-connected with the digital acquisition circuit, the digital acquisition circuit electrically connected and signal-connected with the operation control module, and the operation control module is signal-connected with the man-machine interaction module through the communication module; the operation control module sends a trigger instruction to the high-power ultrasonic excitation module, the high-power ultrasonic excitation module generates a trigger signal, the trigger signal acts on the transducer through the sensor matching circuit to enable the transducer to generate an ultrasonic guided wave signal, the ultrasonic guided wave signal propagates and reflects on the surface of the sensing rod, the transducer receives reflected waves and converts the reflected waves into electric signals, the electric signals are transmitted to the band-pass filter circuit through the sensor matching circuit and then transmitted to the digital acquisition circuit through the gain adjustment circuit to be filtered and amplified, finally the digital acquisition circuit uploads ultrasonic guided wave reflected data to the operation control module, the operation control module processes the ultrasonic guided wave reflected data, and time and/or distance parameters are calculated and data processing results are transmitted to the man-machine interaction module through the communication module; the man-machine interaction module can also reversely adjust preset parameters in the operation control module through a feedback mechanism so as to improve the data processing precision.
As a further explanation of the electrode sounding system of the electrode for the submerged arc furnace according to the present invention, preferably, the man-machine interaction module includes a remote man-machine interaction module and/or an in-situ man-machine interaction module; the remote man-machine interaction module is located at the far end of the electrode sounding system, and the local man-machine interaction module is located at the near end of the electrode sounding system.
As a further explanation of the electrode sounding system of the electrode for a submerged arc furnace according to the present invention, preferably, the electrode sounding system further includes a shielding gas generator, a gas pressure adjusting device, and/or a check valve, the shielding gas generator is connected to the gas pressure adjusting device, the gas pressure adjusting device is connected to the check valve, and the check valve extends into the shielding pipe; the protective gas generator generates protective gas, the protective gas is subjected to pressure conversion through the gas pressure regulating device and is sent to the periphery of the sensing rod through the one-way valve, so that the sensing rod is protected from high-temperature oxidation. In order to achieve another object of the present invention, the present invention also provides an electrode sounding method in a submerged arc furnace using the electrode sounding system for a submerged arc furnace, the electrode sounding method in a submerged arc furnace comprising the steps of:
Step S1): setting a groove or a protrusion on the sensing rod at intervals of delta L, wherein the groove or the protrusion closest to the lower end surface of the sensing rod is an nth groove or protrusion, and the distance from the groove or the protrusion to the lower end surface of the sensing rod is S, wherein S is less than delta L;
step S2): acquiring the total length H of the sensing rod through the operation control device; wherein, the distance from the top end of the sensing rod to the lowest end of the groove or the protrusion is as follows: n×Δl; the nth groove or protrusion of the sensing rod is distant from the lower end face of the sensing rodThe total length of the sensor bar +.>The average speed of the lower end of the ultrasonic guided wave is; ts is the receiving time of the ultrasonic guided wave reflected by the lower end surface of the sensing rod; tn is the receiving time of the ultrasonic guided wave reflected by the nth groove or protrusion;
step S3): the length H of the electrode for the submerged arc furnace outside the submerged arc furnace is measured, and then the depth D=H-H of the electrode for the submerged arc furnace in the submerged arc furnace; the distance between the lower end part of the electrode for the submerged arc furnace and the furnace bottom is as follows: d=l-D, LThe total depth of the submerged arc furnace; wherein, the units of S, H and delta L, h, D, d, L are rice (m); ts and tn are each seconds(s);in meters per second (m/s).
According to the technical scheme, in the running environment of the submerged arc furnace, the temperature of the electrode is gradually increased along with the increase of the depth of the electrode in the furnace. Meanwhile, the transmission speed of the ultrasonic guided wave on the sensing rod is obviously changed along with the increase of the temperature. Because the transmission speed of the ultrasonic guided wave is not constant, in order to improve the measurement accuracy of the length of the sensing rod, the sensing rod is segmented, the number of grooves or protrusions and the average speed of the lower end of the ultrasonic guided wave are respectively obtained, and along with the reduction of delta L, the measurement accuracy is improved. The longitudinal section of the grooves or the protrusions is selected from one or more of triangle, circle or sector, square, polygon and/or irregular shape; wherein, deltaL/sensing rod total length H may be greater than 1/30, or DeltaL/sensing rod total length H is greater than 1/20. The value of Δl depends on the length of the ultrasonic pulse, and when the total Δl/sensing rod length is too small, ultrasonic guided wave signals reflected by different grooves are prone to overlap, resulting in difficulty in distinguishing the reflected signals of the grooves. The control of the delta L is beneficial to the statistics of the reflection quantity of ultrasonic guided waves, so that the quantity of grooves or protrusions on the sensing rod after oxidation consumption is obtained.
The beneficial effects of the invention are as follows: according to the electrode sounding system of the electrode for the submerged arc furnace, the sensing rod is reasonably arranged in the electrode for the submerged arc furnace, the ultrasonic guided wave has the characteristic of reflection at the end face, the groove or the protrusion of the sensing rod, the length of the sensing rod is obtained by measuring the transmission time of the reflected wave at the end part of the guided wave, and meanwhile, the sensing rod can be consumed along with electrode consumption, namely, the length of the sensing rod is consistent with the length of the electrode, namely, the length of the electrode and the depth of the electrode in the submerged arc furnace can be synchronously obtained, the defects of a measuring method of the depth of the electrode in the submerged arc furnace in the prior art, such as poor precision, the need of stopping production and stopping the submerged arc furnace, incapability of continuous measurement, working condition and influence measurement of submerged arc furnace burden, need of manual intervention and the like, are avoided, unexpected effects are obtained, the electrode depth in the submerged arc furnace can be effectively and accurately obtained without stopping production and stopping the submerged arc furnace or manual intervention, thereby providing data basis for controlling the electrode, the purposes of optimizing process operation, saving electric energy, improving product quality and reducing safety are achieved, and great social and economic benefits can be generated.
Detailed Description
For a further understanding of the structure, features, and other objects of the invention, reference should now be made in detail to the accompanying drawings of the preferred embodiments of the invention, which are illustrated in the accompanying drawings and are for purposes of illustrating the concepts of the invention and not for limiting the invention.
The high temperature in a submerged arc furnace, such as a submerged arc furnace, is a vast industrial electric submerged arc furnace and relies on three self-baking electrodes to transfer energy into the submerged arc furnace to thereby smelt the submerged arc furnace burden. As shown in fig. 2 and 3, fig. 3 is also a cross-sectional view of fig. 2 in A-A direction, and three electrode finished product shapes are uniformly arranged in the submerged arc furnace, wherein electrodes 201 for the submerged arc furnace, a submerged arc furnace body 202 and submerged arc furnace burden 203. The electrode is buried in the submerged arc furnace burden to release the work of the electric arc melting submerged arc furnace burden.
As shown in fig. 2 to 5, the invention provides an electrode sounding system of an electrode for a submerged arc furnace, which comprises an electrode 201 for the submerged arc furnace, a protection tube 101, a sensing rod 102, a transducer 103 and an operation control device; the sensing rod 102 is placed in the protection tube 101, the protection tube 101 and the sensing rod 102 are embedded and communicated in the electrode 201 for the submerged arc furnace together, the protection tube 101 and the sensing rod 102 can be synchronously consumed along with the electrode 201 for the submerged arc furnace, and inert gas, nitrogen, carbon dioxide or mixed gas thereof is introduced into the protection tube 101; inert gases include, but are not limited to, one or more of helium, neon, argon, krypton, xenon, radon; the transducer 103 is located on the upper end face and/or the side face of the sensor bar 102, as shown in fig. 5, fig. 5 is an enlarged view of the position I in fig. 2, fig. 5 is an I-1 diagram showing that the transducer 103 is located on the upper end face of the sensor bar 102, fig. 5 is an I-2 diagram showing that the transducer 103 is located on the side face of the sensor bar 102, and the transducer 103 is used for transmitting and/or receiving ultrasonic guided waves, which are reflected on the end face of the sensor bar 102 and transmitted along the sensor bar 102; the operation control device is electrically connected with the transducer 103 and is in signal connection, and is used for acquiring the receiving time and speed of ultrasonic guided wave transmitted along the sensing rod 102 through the transducer 103, calculating the length of the sensing rod 102, and calculating the depth of the electrode 201 for the submerged arc furnace in the submerged arc furnace based on the length of the sensing rod 102. Specifically, the total length H of the sensing rod is calculated according to the receiving time t of the ultrasonic guided wave and the speed v of the ultrasonic guided wave, and the depth D of the electrode for the submerged arc furnace in the submerged arc furnace is determined by subtracting the length H of the electrode for the submerged arc furnace outside the submerged arc furnace from the total length H of the sensing rod. Preferably, the submerged arc furnace electrode 201 includes a self-baking electrode, a graphite electrode, and a carbon electrode.
A sensing rod is placed in a narrow space formed inside an electrode for the submerged arc furnace, and because electromagnetic waves, sound waves and ultrasonic waves are all emitted in a fan shape, echoes cannot be acquired through the narrow space. Meanwhile, because the lower end part of the electrode is high in temperature and has a cavity, the infrared rays and the laser can not effectively acquire reflected light waves, and the length of the space can not be acquired. Therefore, a wave that can be transmitted in a narrow space is required to acquire a space length by echo time. The guided wave has the capability of transmitting along the surface of the object, and the transmission path and the space depend on the shape of the conductor, so that the purpose of acquiring the echo signal through a narrow space is realized. The guided wave is divided into an electromagnetic guided wave and an ultrasonic guided wave, wherein the electromagnetic guided wave needs to reflect electromagnetic waves by means of substances with different dielectric constants of surrounding media, and the dielectric constant of a carbon material is far greater than that of a cavity at the lower end part of the electrode, so that an echo cannot be acquired at the junction of the carbon and the cavity.
Ultrasonic guided waves have the ability to propagate along the surface of the sensing rod and are commonly used in the prior art to detect defects such as corrosion, cracks, etc. in pipes. The invention utilizes the characteristic that the ultrasonic guided wave has reflection on the end face, the groove or the protrusion of the sensing rod, obtains the length of the sensing rod by measuring the transmission time of the reflected wave at the end part of the guided wave, and simultaneously utilizes the sensing rod to consume along with the consumption of the electrode, namely the length of the sensing rod is consistent with the length of the electrode, thus the length of the electrode and the depth of the electrode in the submerged arc furnace can be synchronously obtained.
Because the ultrasonic guided wave can form echo to interfere with the end part of the sensing rod if being in close contact with other objects in the transmission process along the sensing rod, the length of the sensing rod is misjudged, and the sensing rod can be protected by using a protection tube. The protective tube also has the function of preventing the electrode paste and other objects from wrapping the sensing rod, preventing ultrasonic waves from being absorbed and preventing echo signals from being received; meanwhile, the protective tube can be used for transmitting protective gas, so that the sensing rod is prevented from being oxidized in advance by other substances at high temperature and consumed. The selected protective gas has the capability of not generating chemical reaction with the sensing rod in a high-temperature environment, and simultaneously protects the sensing rod in the protective tube from being isolated from air and submerged arc furnace gas and not being oxidized. In the invention, the lower end part of the sensing rod is positioned in the cavity of the ore-smelting furnace burden, the cross section of the cavity is far larger than that of the protective tube, the protective gas loses the high-temperature protective effect on the sensing rod, and the substances rapidly oxidize the sensing rod at high temperature, so that the lower end surface of the sensing rod is leveled with the lower end surface of the protective tube, and materials such as metal, graphite, ceramic and the like of the protective tube react with the high-temperature gas in the cavity, so that the protective tube is leveled with the lower end surface of the electrode, and the realization of the electrode depth measurement is ensured. As the furnace gas can lead the sensing rod to be oxidized in advance, and inert gas or nitrogen is introduced into the through hole, the influence of high-temperature oxidation on measurement accuracy can be prevented, the temperature in the through hole can be further reduced, the temperature difference between the through hole and the cavity is increased, and the measurement accuracy is improved. Meanwhile, the protective gas is filled in the protective tube, so that whether the protective tube is in a smooth state or not can be indicated, and the pressure of the protective gas in the protective tube can be increased if the end head is melted; and also has the function of blowing off the end of the temporary plugging.
In addition, a groove or protrusion is provided on the sensor rod 102 at intervals of Δl for reflecting the ultrasonic guided wave, as shown in fig. 6; the groove or the protrusion closest to the lower end surface of the sensing rod 102 is the nth groove or protrusion, and the distance from the groove or the protrusion to the lower end surface of the sensing rod 102 is S, S < delta L; the ultrasonic guided wave propagates along the sensing rod 102, and each groove or protrusion generates a reflected wave.
The total length H of the sensing rod is as follows:
(1) The distance from the top end of the sensing rod to the lowest groove or protrusion is: n×Δl;
(2) The nth groove or protrusion of the sensing rod is spaced from the lower section of the sensing rod
Total length of sensing rod
Wherein,the average speed of the lower end of the ultrasonic guided wave is;
ts is the receiving time of the reflected wave of the lower end face of the sensing rod; tn is the receiving time of the reflected wave of the nth groove or protrusion;
(3) Depth d=h-H of the electrode in the submerged arc furnace;
the distance from the bottom of the submerged arc furnace electrode 201 to the bottom of the furnace is: d=l-D;
wherein H is the total length of the sensing rod; h is the length of the electrode outside the submerged arc furnace, and L is the total depth of the submerged arc furnace after measurement; s, H, delta L, h,D. d and L are rice (m); ts and tn are each seconds(s);in meters per second (m/s).
In the operating environment of a submerged arc furnace, the temperature of the electrode increases gradually as the depth of the electrode within the furnace increases. Meanwhile, the transmission speed of the ultrasonic guided wave on the sensing rod is obviously changed along with the increase of the temperature. Because the transmission speed of the ultrasonic guided wave is not constant, in order to improve the measurement accuracy of the length of the sensing rod, the sensing rod is segmented, the number of grooves or protrusions and the average speed of the lower end of the ultrasonic guided wave are respectively obtained, and along with the reduction of delta L, the measurement accuracy is improved. The longitudinal section of the grooves or the protrusions is selected from one or more of triangle, circle or sector, square, polygon and/or irregular shape; wherein, deltaL/sensing rod total length H may be greater than 1/30, or DeltaL/sensing rod total length H is greater than 1/20. The value of Δl depends on the length of the ultrasonic pulse, and when the total Δl/sensing rod length is too small, ultrasonic guided wave signals reflected by different grooves are prone to overlap, resulting in difficulty in distinguishing the reflected signals of the grooves. The control of the delta L is beneficial to the statistics of the reflection quantity of ultrasonic guided waves, so that the quantity of grooves or protrusions on the sensing rod after oxidation consumption is obtained.
The temperature in the submerged arc furnace is very high, for example, the temperature of the electrode end part of the submerged arc furnace is as high as 1600-2200 ℃, the submerged arc furnace is buried in the submerged arc furnace material, any sensor cannot survive in the environment, moreover, the electrode is made of graphitized carbon material, the length is about 15-20 m, and any electromagnetic wave, sound wave, light wave and terahertz wave cannot penetrate. The outer edge of the electrode is protected by the ore-smelting furnace burden, the ore-smelting furnace bricks and the ore-smelting furnace steel plate, and even if X rays, alpha rays, beta rays, gamma rays and neutron rays are adopted, the electron acceleration can be required to penetrate, so that the cost is about 500-1000 ten thousand, the cost is unacceptable economically, and meanwhile, the radiation pollution is caused. The system for measuring the electrode depth by utilizing the ultrasonic guided wave provided by the invention can penetrate through a thick electrode to reach the electrode end, can simultaneously send a wave signal for detection to the electrode end, and can acquire an echo signal. Thereby realizing the measurement of the length of the electrode and further realizing the measurement of the depth of the electrode into the submerged arc furnace.
Preferably, as shown in fig. 7, the operation control device comprises an operation control module 110, the operation control module 110 is electrically connected with and in signal connection with a high-power ultrasonic excitation module 105, the high-power ultrasonic excitation module 105 is electrically connected with and in signal connection with a sensor matching circuit 104, the sensor matching circuit 104 is electrically connected with and in signal connection with a transducer 103 and a band-pass filter circuit 107 respectively, the band-pass filter circuit 107 is electrically connected with and in signal connection with a gain adjustment circuit 108, the gain adjustment circuit 108 is electrically connected with and in signal connection with a digital acquisition circuit 109, the digital acquisition circuit 109 is electrically connected with and in signal connection with the operation control module 110, and the operation control module 110 is in signal connection with a man-machine interaction module through a communication module 111; the operation control module 110 sends a trigger instruction to the high-power ultrasonic excitation module 105, the high-power ultrasonic excitation module 105 generates a trigger signal, the trigger signal acts on the transducer 103 through the sensor matching circuit 104 to enable the transducer 103 to generate an ultrasonic guided wave signal, the ultrasonic guided wave signal propagates and reflects on the surface of the sensing rod 102, the transducer 103 receives reflected waves and converts the reflected waves into electric signals, the electric signals are transmitted to the band-pass filter circuit 107 through the sensor matching circuit 104 and then transmitted to the digital acquisition circuit 109 through the gain adjustment circuit 108 for filtering and amplifying, finally the digital acquisition circuit 109 uploads ultrasonic guided wave reflected data to the operation control module 110, the operation control module 110 processes the ultrasonic guided wave reflected data, calculates time and/or distance parameters and transmits a data processing result to the man-machine interaction module through the communication module 111; the man-machine interaction module can also reversely adjust preset parameters in the operation control module 110, including the terminal sound velocity, through a feedback mechanism so as to improve the data processing precision. The man-machine interaction module can adjust operation fixed values in the operation control module, such as delta L length, average sound velocity of the lower end part of the sensing rod and measurement period, and the operation result is affected.
The man-machine interaction module comprises a remote man-machine interaction module 112 and/or an in-situ man-machine interaction module 113; the remote man-machine interaction module 112 is located at the far end of the electrode sounding system, and the in-situ man-machine interaction module 113 is located at the near end of the electrode sounding system.
Preferably, as shown in fig. 7, the electrode sounding system further comprises a protective gas generator 114, a gas pressure regulating device 115 and/or a check valve 116, wherein the protective gas generator 114 is connected with the gas pressure regulating device 115, the gas pressure regulating device 115 is connected with the check valve 116, and the check valve 116 extends into the protective tube 101; wherein, the protective gas generator 114 generates protective gas, which is sent to the periphery of the sensing rod 102 through the one-way valve 116 by pressure conversion of the gas pressure regulating device 115 to protect the sensing rod 102 from high temperature oxidation.
Preferably, the transducer 103 is an electromagnetic ultrasonic transducer and/or a magnetostrictive transducer and/or a piezoelectric transducer.
Preferably, the melting point of the protection tube 101 is above 2000 ℃, and the protection tube 101 is made of one or more of metal materials, graphite and/or ceramic materials; the metal material is selected from one or more of tungsten, molybdenum, rhenium, iridium and lanthanum monomers and/or mixtures; the ceramic material is one or more of aluminum oxide, zirconium oxide, magnesium oxide, silicon carbide, molybdenum silicide, molybdenum carbide, titanium carbide monomer or mixture thereof, zirconium oxide or aluminum oxide aerogel and/or aerogel fiber.
Through repeated experimental researches of the inventor, the selected material of the protective tube has the advantage of synchronous consumption with the electrode for the submerged arc furnace, so that the length of a sensing rod arranged in the protective tube is ensured, the close correlation between the electrode for the submerged arc furnace and the depth of the electrode for the submerged arc furnace in the submerged arc furnace is ensured, and the accuracy of electrode depth measurement is further ensured. Further, the metal material can be used for preventing the protection tube from being crushed by the spherical electrode paste, and meanwhile, the graphite material also has the function of preventing the paste electrode paste from corroding the protection tube, and the graphite material can be used for supporting the lower end part of the protection tube, so that the protection tube is kept smooth at high temperature and prevented from being blocked by molten metal of the metal tube. The ceramic material can be used for preventing the sensing rod from being chemically reacted with graphite at high temperature to lead to the purpose of premature fusing. The protection tube is in a regular and/or irregular tubular shape, including but not limited to one or more of square tube, round tube, elliptical tube, polygonal tube, and irregularly shaped tube, as shown in fig. 4, fig. 4 is an enlarged view of a position ii in fig. 3, fig. 4 is a view ii-1 showing an example in which the protection tube 101 is a round tube, and fig. 4 is a view ii-2 showing an example in which the protection tube 101 is a square tube.
Preferably, the melting point of the sensing rod 102 is above 2000 ℃, and the sensing rod 102 is made of one or more of metal materials, graphite and/or ceramic materials; the metal material is selected from one or more of tungsten, molybdenum, rhenium, iridium and lanthanum monomers and/or mixtures; the ceramic material is selected from one or more of aluminum oxide, zirconium oxide, magnesium oxide, silicon carbide, and monomer and/or mixture of molybdenum silicide. Preferably, the melting point of the sensing rod 102 is above 2200 ℃, and the sensing rod 102 is made of one or more of graphite, alumina, zirconia, magnesia, tungsten and/or a mixture of monomers.
Through repeated experimental researches of the inventor, the selected material of the sensing rod can ensure that the sensing rod has good ultrasonic guided wave transmission and reflection performance, so that on one hand, the problem that the sensing rod melts in an electrode for an submerged arc furnace, thereby absorbing ultrasonic guided waves and being difficult to form reflected waves is avoided; on the other hand, the high-temperature easily-oxidized material is adopted, so that the part of the sensing rod beyond the electrode end can be oxidized by furnace gas at high temperature, the consumption of the sensing rod together with the electrode for the submerged arc furnace is realized, the purpose of indicating the position of the electrode is achieved, and the accuracy of electrode depth measurement in the submerged arc furnace is ensured.
When the submerged arc furnace electrode works, the submerged arc furnace electrode can be positioned at the end of the electrode under the action of electric arc and furnace gas
The size of the cavity is related to the smelted variety and furnace condition, extremely high temperature and a large amount of gas are generated in the cavity due to arc discharge, the internal temperature of the electrode tip is about 2000-3000 ℃ and is far lower than the temperature of the cavity, the lower end face of the electrode is positioned at an arcing position, the temperature in the cavity rises suddenly, the estimated temperature is 4000-10000 ℃, the electrode temperature curve is shown in figure 1, and the transverse axis in figure 1 represents the temperature curve of the electrode H from the top end to the low end to the cavity. As can be seen from fig. 1, the position of the end of the acquisition electrode is the position of the gas interface between the acquisition electrode and the cavity.
According to the invention, a through hole is pre-buried from the inside of the electrode, through the research of the inventor, a sensing rod (shown in figure 2) with the melting point higher than 2000 ℃ and preferably 2200 ℃ is placed in the through hole, and when the sensing rod passes through the middle hole of the electrode, the sensing rod reaches the position of the interface between the lower end surface of the electrode and the cavity, and the protruding part is rapidly melted and oxidized. When the electrode is gradually consumed, the sensing rod can realize synchronous consumption along with the electrode in the submerged arc furnace, at the moment, the length of the sensing rod represents the length of the electrode, and the depth of the electrode inserted into the furnace can be calculated by measuring the length of the sensing rod and the depth of the electrode outside the furnace.
The electrode sounding system of the electrode for the submerged arc furnace provided by the invention can be used for sounding the electrode in an electric arc submerged arc furnace and/or a resistance submerged arc furnace for smelting ores and carbonaceous reducing agents; preferably from the group consisting of iron alloy submerged arc furnace, calcium carbide submerged arc furnace, yellow phosphorus submerged arc furnace, silicon calcium carbide submerged arc furnace, silicon carbide submerged arc furnace and/or industrial silicon submerged arc furnace. In the use process of the submerged arc furnace, the depth of the electrode inserted into the submerged arc furnace is extremely important for the smelting process. The smelting process requires that the power center and the geometric center of the three-phase electrode are coincident and the insertion depth is reasonable, so that good smelting efficiency and low energy consumption can be obtained, the unreasonable electrode depth position also leads to the occurrence of a raw material layer during roasting, influences the product quality, and is easy to cause accidents such as equipment damage and casualties caused by spraying, so that the accurate acquisition of the insertion depth of the electrode is extremely necessary for safe and efficient production in the smelting industry of the submerged arc furnace.
The invention also provides an electrode sounding method in the submerged arc furnace, which is realized by the electrode sounding system of the electrode for the submerged arc furnace and comprises the following steps:
step S1): a groove or a protrusion is arranged on the sensing rod 102 at intervals of delta L, the groove or the protrusion closest to the lower end surface of the sensing rod 102 is an nth groove or protrusion, and the distance from the groove or the protrusion to the lower end surface of the sensing rod 102 is S, wherein S < delta L; as shown in fig. 6.
Step S2): the total length H of the sensor bar 102 is obtained by the arithmetic control device.
Wherein the grooves or protrusions are formed from the top end to the lowest end of the sensor bar 102The distance of the objects is as follows: n×Δl; the nth groove or protrusion of the sensor bar 102 is spaced from the lower end surface of the sensor bar 102The total length of the sensor bar 102The average speed of the lower end of the ultrasonic guided wave is; ts is the receiving time of the ultrasonic guided wave reflected by the lower end surface of the sensing rod 102; tn is the reception time of the ultrasonic guided wave reflected by the nth groove or protrusion.
Step S3): the length H of the submerged arc furnace electrode 201 outside the submerged arc furnace is measured, and then the depth d=h-H of the submerged arc furnace electrode 201 inside the submerged arc furnace is measured, wherein the distance from the bottom of the submerged arc furnace electrode 201 to the bottom of the submerged arc furnace is: d=l-D, L being the total submerged arc furnace depth.
The units of S, H and delta L, h, D, d, L are rice (m); ts and tn are each seconds(s);in meters per second (m/s).
Example 1
One embodiment of an electrode sounding system for an electrode for a submerged arc furnace according to the present invention:
the electrode sounding system comprises a protection tube 101, a sensing rod 102, a transducer 103, a sensor matching circuit 104, a high-power ultrasonic excitation module 105, a storage module 106, a band-pass filter circuit 107, a gain adjustment circuit 108, a digital acquisition circuit 109, an operation control module 110, a communication module 111, a remote man-machine interaction module 112, an on-site man-machine interaction module 113, a protection gas generator 114, a gas pressure regulating device 115 and a one-way valve 116.
Wherein, the protection tube 101 is embedded and penetrated in the electrode 201 for the submerged arc furnace, the electrode 201 for the submerged arc furnace adopts a self-baking electrode, and the protection tube 101 is made of graphite and square tubes with the side length of 30 mm; the sensing rod 102 is made of tungsten, the cross section is 2.5 mm long diameter, and the ratio of the long diameter to the short diameter is 2:1 are arranged in the protection tube 101; transducer 103 is mounted on a side end face of sensor stem 102 as shown in fig. 5, I-2.
The shielding gas generator 114 generates a shielding gas (hereinafter referred to as shielding gas) that does not chemically react with the sensor rod 102 in a high-temperature environment of use, such as helium. After the pressure of the shielding gas is changed by the gas adjusting device 115, the ventilation pressure is kept at 1.10 atm, and the shielding gas is sent to the shielding pipe 101 through the one-way valve 116 to perform high-temperature protection on the sensing rod 102.
The remote man-machine interaction module 112 and the on-site man-machine interaction module 113 transmit the data acquisition instruction to the operation control module 111 through the communication module 111, software in the operation control module 110 sends signals to the high-power ultrasonic excitation module 105 to generate trigger signals, the trigger signals are acted on the transducer 103 through the sensor matching circuit 104, the transducer 103 converts electric signals into ultrasonic signals, the ultrasonic signals are transmitted to the lower end face through the sensing rod 102 to generate reflected echoes, the transducer 103 converts the reflected echoes into electric signals to be transmitted to the sensor matching circuit 104 to be transmitted to the band-pass filter circuit 107, the electric signals are transmitted to the digital acquisition circuit 109 to be filtered and amplified after passing through the gain adjustment circuit 108, and the storage module 106 uploads data to the operation control module 110.
The operation control module 110 processes the ultrasonic guided wave reflection data to calculate data such as time, distance and the like, for example, the receiving time t of ultrasonic guided waves and the like, and combines the ultrasonic guided wave speed v, and the total length H=t×v/2 of the sensing rod is obtained according to the formula; and according to the customized data H measured by the pull rope distance meter, the depth of the electrode in the submerged arc furnace is obtained by using the formula electrode depth D=H-H.
The operation control module directly transmits the calculated time and distance data including the length of the sensing rod, the depth of the electrode in the submerged arc furnace and the like to the remote man-machine interaction module 112 through the communication module 111 or to the local man-machine interaction module 113 through the communication module 111.
The man-machine interaction module (the remote man-machine interaction module 112 and the on-site man-machine interaction module 113) can transmit the set constant value to the operation control module, so that customization in the operation control module is changed, and data such as time and distance can be calculated by software in the operation control module conveniently.
Example 2
Another embodiment of the electrode sounding system of the submerged arc furnace electrode of the present invention:
the electrode sounding system comprises a protection tube 101, a sensing rod 102, a transducer 103, a sensor matching circuit 104, a high-power ultrasonic excitation module 105, a storage module 106, a band-pass filter circuit 107, a gain adjustment circuit 108, a digital acquisition circuit 109, an operation control module 110, a communication module 111, a remote man-machine interaction module 112, an on-site man-machine interaction module 113, a protection gas generator 114, a gas pressure regulating device 115 and a one-way valve 116. The protection tube 101 is embedded in the submerged arc furnace electrode 201, and the submerged arc furnace electrode 201 is a circular tube with a diameter of 30mm by using a self-baking electrode. The protection tube 101 has a two-layer structure, wherein the outer layer is made of graphite material, and the inner layer is made of zirconia aerogel. The sensing rod 102 is made of molybdenum-lanthanum alloy, the cross section of the sensing rod is in a cylindrical shape with a diameter of 1.5 mm, and the sensing rod is arranged in the protection tube 101; a groove is arranged on the sensing rod 102 every 100cm and used for reflecting ultrasonic guided waves, the longitudinal section of the groove is semicircular, and a transducer 103 is arranged on the upper end face of the sensing rod 102, as shown in the I-1 diagram in fig. 5.
The shielding gas generator 114 generates a shielding gas (hereinafter referred to as shielding gas) that does not chemically react with the sensor rod in a high-temperature environment of use, such as helium. After the pressure of the shielding gas is changed by the gas adjusting device 115, the ventilation pressure is kept at 1.05 atm, and the shielding gas is sent to the shielding pipe 101 through the one-way valve 116 to perform high-temperature protection on the sensing rod 102.
The remote man-machine interaction module 112 and the on-site man-machine interaction module 113 transmit the data acquisition instruction to the operation control module 111 through the communication module 111, software in the operation control module 110 transmits a signal through the high-power ultrasonic excitation module 105 to generate a trigger signal, the trigger signal acts on the transducer 103 through the sensor matching circuit 104, the transducer 103 converts an electric signal into an ultrasonic signal, the ultrasonic signal propagates to the lower end face through the sensing rod 102 to generate a reflected echo, the transducer 103 converts the reflected echo into the electric signal to be transmitted to the band-pass filter circuit 107, the electric signal is transmitted to the digital acquisition circuit 109 for filtering and amplifying after passing through the gain adjustment circuit 108, and then the data is uploaded to the operation control module 110; the operation control module 110 processes the ultrasonic guided wave reflection data to calculate data such as time and distance, for example:
And obtaining the n-th groove closest to the lower end face of the sensor from the number of reflected waves and the average speed of ultrasonic guided waves. Acquiring the receiving time ts of the reflected wave of the lower end surface of the sensing rod and the receiving time tn of the reflected wave of the nth groove;
using the formula:the total length H4, H5 and H6 of the sensing rod is obtained.
And according to the custom data H measured by the laser range finder, the depth of the electrode in the submerged arc furnace is obtained by using the formula electrode depth D=H-H.
The operation control module directly transmits the calculated time and distance data including the length of the sensing rod, the depth of the electrode in the submerged arc furnace and the like to the remote man-machine interaction module 112 through the communication module 111 or to the local man-machine interaction module 113 through the communication module 111.
The man-machine interaction module (the remote man-machine interaction module 112 and the on-site man-machine interaction module 113) can transmit the set constant value to the operation control module, so that customization in the operation control module is changed, and data such as time and distance can be calculated by software in the operation control module conveniently.
Example 3
In a carbide submerged arc furnace with a capacity of 33000kvA, the measurement results of the electrode depths are compared by adopting different test methods for the self-baking electrode at a submerged arc furnace temperature of about 1800-2200 ℃.
Comparative embodiment 1 employed in the prior art for measuring electrode length:
the self-baking electrode 1 was subjected to an accumulation method, and the electrode length was estimated from the electrode paste added every day and the rate of consumption. The depth of the self-baking electrode in the submerged arc furnace was estimated on days 7, 14 and 21, respectively, to give electrode depths of about 1.3m, 0.9m and 0.6m.
The invention provides an electrode sounding system and an electrode sounding method for an electrode for a submerged arc furnace, which are one implementation mode of the electrode sounding system and the electrode sounding method for the electrode for the submerged arc furnace:
the self-baking electrode 1 is internally embedded with a through protection tube, the outer layer of the protection tube is graphite, and the inner layer is an alumina coating. The protection tube is in a regular and/or irregular tubular shape, including but not limited to one or more of a square tube, a round tube, an elliptical tube, a polygonal tube and an irregularly-shaped tube, and in this embodiment, the protection tube is a regular round tube with an inner diameter of 30mm. The sensing rod is made of molybdenum, and a solid column with the cross section of 2 mm and the diameter of a circle is arranged in the protection tube; the transducer is a magnetostrictive transducer and is arranged on the upper end surface of the sensing rod.
The protective tube is internally filled with protective gas nitrogen, the ventilation pressure is 1.05 atmospheres, the protective gas can protect the sensing rod from oxidation at high temperature, and meanwhile, the lower end face of the sensing rod is not protected along with the overflow of the protective gas at the lower end face of the sensing rod, so that the sensing rod and the self-baking electrode are consumed due to oxidation, and the sensing rod and the self-baking electrode are kept at the same length.
The ultrasonic guided waves are transmitted by the transducer on the 7 th day, the 14 th day and the 21 st day respectively, so that the ultrasonic guided waves are transmitted along the sensing rod, the transmission speed of the ultrasonic guided waves is 5625m/s, the ultrasonic guided waves are reflected after reaching the bottom of the sensing rod, and the transducer receives the reflected waves and converts the reflected waves into electric pulse signals; the receiving time of the ultrasonic guided wave is 7.11ms, 6.90ms and 6.76ms, and the total length H of the sensing rod is 20m, 19.4m and 19m, which is obtained by 1/2 of the product of the receiving time t of the ultrasonic guided wave and the speed v of the ultrasonic guided wave; the length H of the electrode outside the submerged arc furnace is measured to be 18.75m, 18.28m and 18.00m by an infrared range finder, and the length H of the electrode outside the submerged arc furnace is subtracted by the total length H of the sensing rod to obtain the depths of the electrode inside the submerged arc furnace of 1.25m, 1.12m and 1.00m.
After measuring the electrode depth by using ultrasonic guided waves on the 7 th day, the 14 th day and the 21 st day, stopping the submerged arc furnace, lifting the electrode until the lower end face is exposed out of the submerged arc furnace burden, and measuring the actual electrode lengths by using lasers to be 19.95m, 19.46m and 19.06m respectively. And combining the lengths h of the electrodes outside the submerged arc furnace, which are respectively measured, to obtain the actual depths of the electrodes in the submerged arc furnace of 1.20m, 1.18m and 1.06m.
As can be seen from the following Table 1, the method for measuring the electrode depth by using the ultrasonic guided wave has the accuracy reaching about 95%, is far higher than the accumulation method used in the prior art, is sufficient for improving the product quality, can replace shutdown of the submerged arc furnace, and has extremely high social and economic values.
TABLE 1
Example 4
In a carbide submerged arc furnace with a capacity of 33000kvA, the measurement results of the electrode depths are compared by adopting different test methods for the self-baking electrode at a submerged arc furnace temperature of about 1800-2200 ℃.
Comparative embodiment 2 employed in the prior art for measuring electrode length:
for the self-baking electrode 2, a probe method is adopted, a drill rod is inserted into the submerged arc furnace to touch the electrode, the end face of the electrode is detected through multiple insertion probes, and then the insertion depth of the electrode is calculated by using the Pythagorean theorem. And calculating and measuring the depth of the self-baking electrode in the submerged arc furnace on the 8 th day, the 16 th day and the 24 th day respectively to obtain the data of 1.2m, 1.0m and 0.9m of electrode depth.
The invention provides another embodiment of an electrode sounding system and method for an electrode for a submerged arc furnace:
the self-baking electrode 2 is embedded with a through protection tube which is a regular square tube with the side length of 50mm. The protective tube is made of graphite material. The sensing rod is made of tungsten-rhenium alloy, the length of the cross section is 5 mm, the width is a rectangular solid column of 0.5 mm, and the sensing rod is arranged in the protection tube and has the length of 19m; the transducer is a piezoelectric transducer and is arranged on the side end face of the sensing rod.
A groove is arranged on the sensing rod every 120cm and used for reflecting ultrasonic guided waves, the longitudinal section of the groove is of an equilateral triangle, and the transducer is arranged on the upper end face of the sensing rod. Meanwhile, because the self-baking electrode, the protection tube and the sensing rod are consumed in the submerged arc furnace, the protection tube and the sensing rod with the length of 1.2m are timely supplemented while the self-baking electrode is manufactured by supplementing electrode paste every day, and the self-baking electrode, the protection tube and the sensing rod are connected with the embedded protection tube and the sensing rod through threads or welding.
The protective tube is filled with protective gas argon, and the ventilation pressure is 1.05 atm. The protective gas can protect the sensing rod from oxidation at high temperature in the protective tube, and meanwhile, the lower end surface of the sensing rod is not protected along with the overflow of the protective gas at the lower end surface of the sensing rod, so that the sensing rod and the self-baking electrode are kept at the same length due to consumption caused by oxidation.
On the 8 th day, the 16 th day and the 24 th day, the transducer is enabled to emit ultrasonic guided waves, the ultrasonic guided waves are transmitted along the sensing rod, secondary and more reflection waves are filtered, the number of primary reflection waves received is calculated to be 19, 18 and 19 respectively, the number of reflection waves of the lower end face is subtracted to be 1, and therefore grooves closest to the lower end face of the sensing rod are 18 th, 17 th and 18 th grooves. It is known that the distance from the groove closest to the lower end face of the sensor bar to the upper end face of the sensor bar is 21.6m, 20.4m, 21.6m.
After simulation calculation, the average speed 3786m/s of the ultrasonic guided wave is measured, and the receiving time of the reflected wave of the lower end face of the sensing rod is 11.83ms, 11.25ms and 11.57ms, and the receiving time of the reflected wave of the 18 th, 17 th and 18 th grooves on the 8 th, 16 th and 24 th days is 11.41ms, 10.78ms and 11.41ms.
Using the formula:The total length of the sensing rod is 22.40m, 21.29m and 21.90m respectively;
the length h of the electrode outside the submerged arc furnace is 21.12m, 20.11m and 20.75m respectively by using a laser range finder;
from d=h-H; the depth of the electrode in the submerged arc furnace is 1.28m, 1.18m and 1.15m.
After measuring the electrode depth by using ultrasonic guided waves on the 8 th day, the 16 th day and the 24 th day, the submerged arc furnace is stopped, the electrode is lifted to the lower end face to expose the submerged arc furnace burden, and the actual electrode lengths are measured by using lasers and are 22.42m, 21.32m and 21.87m respectively. And combining the lengths h of the electrodes outside the submerged arc furnace, which are respectively measured, to obtain the actual depths of the electrodes in the submerged arc furnace of 1.30m, 1.21m and 1.12m.
As can be seen from the following Table 2, the method for measuring the electrode depth by using the ultrasonic guided wave provided by the invention has the accuracy reaching more than 97%, is far higher than that of a probe method used in the prior art, is sufficient for improving the product quality, can replace a shutdown ore-smelting furnace, and has extremely high social and economic values.
TABLE 2
It should be noted that the foregoing summary and the detailed description are intended to demonstrate practical applications of the technical solution provided by the present invention, and should not be construed as limiting the scope of the present invention. Various modifications, equivalent alterations, or improvements will occur to those skilled in the art, and are within the spirit and principles of the invention. The scope of the invention is defined by the appended claims.