Gas extraction device and gas analysis device for extracting hot dust-loaded gas from exhaust gas line of metallurgical plant

Abstract

The invention relates to the field of gas removal of dust-laden gases in metallurgical plants and treatment of the gases for gas analysis. In one aspect, the invention relates to a gas removal device (1) for removing hot dust-laden gas from an exhaust gas line (2) of a metallurgical plant, in particular an oxygen converter or an electric arc furnace. The hot dust-loaded gas has a ferromagnetic particulate material. The removal pipe (3) is arranged in the exhaust gas line in such a way that a partial flow of the gas is removed, the cooling section (4), the gas cleaning section (6), the analysis section (7a), the gas feed unit (8) and the return pipe (9) being arranged downstream of the removal pipe. In another aspect, the invention relates to a gas analysis device comprising a gas extraction device (1). The aim of the invention is to provide a device which allows the gas composition of hot dust-laden exhaust gases to be measured with low time delay, low measurement uncertainty and high fail-safe. This object is achieved in that the gas cleaning section 6 has a magnetic particle separator, by means of which ferromagnetic particle material is separated from the partial flow of the gas in corresponding fractions.

Description

Technical Field

[0001] This invention relates to the field of extracting dust-laden gas in a metallurgical facility and processing the gas for gas analysis.

[0002] On one hand, the present invention relates to a gas extraction device for extracting hot, dust-laden gas from the exhaust gas pipeline of a metallurgical facility, particularly an oxygen-blown converter or an electric arc furnace. The hot, dust-laden gas contains ferromagnetic particulate material. The extraction pipe is arranged in the exhaust gas pipeline such that a portion of the extracted gas flows, wherein, after the extraction pipe, the following is arranged: - Cooling section used to cool ferromagnetic particulate materials to temperatures below 750°C; - Gas cleaning section; - Analysis section; - Gas delivery unit; and - Return tube.

[0003] On the other hand, the present invention relates to a gas analysis apparatus including the gas extraction device. Background Technology

[0004] The following describes a gas extraction device for removing hot, dust-laden gas from exhaust gas pipelines and / or exhaust gas treatment units in metallurgical facilities. These facilities are particularly oxygen-blown converters or electric arc furnaces, where the hot, dust-laden gas contains ferromagnetic particulate material. Here, exhaust gas temperatures of 200°C–1000°C and typically up to 100 g / m³ are observed at the location of the gas extraction device. 3 Particle loading, where this data is based on 0°C and 1 bar.

[0005] Waste gas analysis is frequently used in steel plants to analyze or adjust metallurgical processes. This can, for example, optimize raw material consumption, extend the lifespan of facility components, shorten production time, or maximize the energy utilization of process gases or waste gases.

[0006] On one hand, a so-called extraction measurement method is used to analyze the composition of the exhaust gas. Here, gas is extracted from the exhaust pipeline, cleaned, dried, and then supplied to a gas analyzer. The typical dead time for this analysis is 15-30 seconds. This order of magnitude of dead time adversely affects the dynamics of the control loop described above. Furthermore, as the length of this dead time increases, facility safety decreases because the explosive gas mixture is identified only later, and therefore, a response can only be made later, for example, by switching gas valves.

[0007] On the other hand, so-called in-situ measurement methods are used to analyze exhaust gas composition. Here, optical methods, such as laser optics, are used to determine the gas composition directly within the gas pipeline. The reliability of the measurement is highly dependent on the dust load in the exhaust gas flow. Excessive dust load can lead to severe measurement noise and even temporary measurement failure. This can also result in unsatisfactory regulation characteristics, potentially jeopardizing facility safety. Furthermore, such systems consume large amounts of scavenging air and incur high maintenance costs.

[0008] Furthermore, a system for gas analysis characterized by the two measurement principles mentioned above is described. In EP3809111A1, the extractor pipe is arranged in the exhaust gas line such that a portion of the gas is extracted. Following the extractor pipe are arranged a cooling section for cooling the gas or any particulate material it contains, a gas cleaning section, an analysis section, a gas delivery unit, and a return pipe. Disadvantageously, such systems incur significant maintenance costs due to the filters used. Furthermore, undesirable dead times occur, which are attributed to the volume of gas extraction equipment, including filters and other components for gas processing, that needs to be processed. Summary of the Invention

[0009] The object of the present invention is to provide an apparatus that allows a portion of hot, dust-laden exhaust gas to be extracted and processed in such a way that the gaseous composition of the exhaust gas can be measured with low time delay, low measurement uncertainty and high fail-safety.

[0010] This objective is achieved by the following method: the gas cleaning section has a magnetic particle separation section formed by a flat channel with a rectangular cross-section having an aspect ratio of less than 1:5, preferably less than 1:10, wherein, preferably, magnets are arranged on the outside at least on the wide side of the flat channel. The flat channel enables particularly good adhesion of the particles to be separated because, on the one hand, only a small penetration depth is required for the magnetic field, and on the other hand, a large surface area for particle separation is provided inside the flat channel. Furthermore, the relatively large surface area of ​​the flat channel results in particularly efficient cooling of the measuring gas. Preferably, electromagnets and / or permanent magnets are provided on the outside of the flat channel, whose magnetic fields act on / above the flat channel in such a way that ferromagnetic dust present there and non-ferromagnetic dust partially attached to the ferromagnetic dust are held by magnetic force on the inside of the flat channel.

[0011] The gas cleaning section has a magnetic particle separation section, which is designed such that at least 30%, preferably 50%, particularly preferably 70%, and very particularly preferably 80% of ferromagnetic particles with a size greater than 0.15 µm are separated from a portion of the gas stream.

[0012] Experience has shown that the separation of such particulate materials is sufficient to achieve reliable results using known optical gas analyzers.

[0013] The magnetic force on ferromagnetic particles in a magnetic field can be utilized to: (Equation 1) To make an analytical estimate, where H is the magnetic field and V is... p Here, µ is the volume of the particle, µ0 is the vacuum permeability, and µ... r1 It is the relative magnetic permeability of the particulate material.

[0014] The magnetic field must be configured in its strength and design such that the magnetic force associated with the particles exceeds the hydrodynamic force and gravity, thereby separating the ferromagnetic particle material in the manner described above.

[0015] In order to magnetically separate ferromagnetic particulate materials, they need to be cooled below the Curie temperature. This is done in the cooling section.

[0016] The cooling section is formed by an outlet pipe through which heat is dissipated to the surrounding environment by means of a medium, such as water, gas, or other cooling medium, or by other mechanisms, such as natural convection. The gas flow rate achieved through this gas outlet pipe must be set so that ferromagnetic particles present in the gas can be cooled below their Curie temperature before reaching the magnet separator.

[0017] In one advantageous embodiment, the volume of the gas extraction device from the extraction tube (inclusive) to the optical gas analyzer (inclusive) is less than 0.3 m³. 3 Preferably less than 0.15 m 3 Preferred size is less than 0.05 m. 3 .

[0018] In another advantageous embodiment, the gas cleaning section includes at least one guide vane arranged such that the dust-laden gas is deflected toward the magnetic particle separation section. If a larger particle collides with the guide vane, the particle is decelerated and can be captured by the magnetic particle separation section with a greater probability. This thus influences the flow guidance, causing the dust-laden gas to be guided closer to the magnetic wall of the gas cleaning section, and thus achieving more efficient separation of dust particles.

[0019] In another advantageous embodiment, the gas cleaning section has at least a portion of a non-ferromagnetic material in the wall region where the magnetic particle separation section is located, and preferably has a smaller wall thickness than in the remaining wall regions.

[0020] This avoids magnetic short circuits, which results in a higher magnetic field strength inside the magnetic particle separation section and thus improves particle separation.

[0021] In another advantageous embodiment, an iron core extension made of ferromagnetic material is arranged between the wall of the gas cleaning section and the magnetic particle separation section, the iron core extension guiding the magnetic field closer to the gas cleaning section. The iron core extension can, for example, be inserted into the wall of the gas cleaning section. This magnetically bridges the gap between the magnet and the gas cleaning section, and / or influences the shape and strength of the magnetic field in a region of the gas cleaning section. This allows for different influences on the magnetic field strength in different regions of the gas cleaning section, and thus optimizes the shape of the magnetic field in the gas cleaning section according to Equation 1, thereby achieving the most thorough possible separation of magnetic particles.

[0022] In another advantageous embodiment, the core extension of the magnetic particle separation section of the gas cleaning section has a cooling device, preferably an air cooling device or a water cooling device.

[0023] Thus, despite the higher temperature in the gas cleaning section, improved magnetic permeability of the core was achieved. This resulted in a higher magnetic field strength within the gas cleaning section and consequently improved particle separation.

[0024] In another advantageous embodiment, an electromagnet and / or a permanent magnet are provided on at least one outer side of the flat channel, preferably on at least one wide side of the flat channel, wherein the electromagnet and / or the permanent magnet preferably has a cooling device, particularly preferably an air cooling device or a water cooling device.

[0025] Thus, despite the higher temperature in the gas cleaning section, the magnet still achieved its improved effect. This resulted in a higher magnetic field strength inside the gas cleaning section and consequently improved particle separation.

[0026] A cleaning device is arranged after the gas cleaning section, comprising: at least one cleaning pipe for generating an airflow that removes the separated particulate material from the gas cleaning section; and preferably additionally movable flaps that primarily guide the airflow to be cleaned through the gas cleaning section during the cleaning time. The oxygen converter or electric arc furnace operates periodically. This work cycle includes time periods between stages in which metallurgical processes are performed and gas analysis measurements are continuously required, during which no measurement data is needed. During these time periods, the magnetic particle separator can be cleaned by de-energizing the activating magnetic field and / or by removing the separated particulate material from the gas cleaning section using artificially generated airflow. Here, the closed flaps ensure that the airflow to be cleaned is guided through the gas cleaning section and does not leak out unused. The geometry of the gas extraction device allows particles to be gravity-supported and transported back to the exhaust gas line after detaching from the inner wall of the gas cleaning section. Similarly, during these time periods, components made of ferromagnetic material that have been subjected to the magnetic field of the magnetic particle separator can be demagnetized. After cleaning is completed, the magnetic field is re-energized, and the gas cleaning section is once again available for the process.

[0027] Cleaning equipment for repeatedly removing particles that are magnetically held inside a flat channel is preferably a blowing device, but it can also be implemented as a tapping device or a mechanical scraper.

[0028] Cleaning equipment can also be formed by a gas supply section in the area between the analysis section and the gas delivery unit within the range of the sidewall of the flow channel and / or by a device for switching the pumping direction of the gas delivery unit.

[0029] A gas delivery unit is used to transport the dust-laden gas to be analyzed from the take-off pipe to the return pipe. This can be, for example, a fan or a jet pump.

[0030] Regarding the measurement of the gas flow, a calibration gas flap and at least one calibration gas inlet are located upstream of the analysis section, enabling calibration of the analysis section in the loaded state. For this purpose, a gas with a known composition is introduced into the analysis section after the movable flap is closed. The analysis section, which incorporates an optical gas analyzer in the application, can then be calibrated.

[0031] In an advantageous embodiment, the gas extraction device has a compensator between the cooling section and the analysis section for compensating for thermal deformation and / or decoupling mechanical vibration, wherein the compensator is implemented, for example, as a bellows.

[0032] In another advantageous embodiment of the gas extraction device, a bypass line is arranged adjacent to the analysis section, wherein the bypass line is oriented along the main flow direction of the dust-laden gas, and wherein the gas line branches off from the main flow direction, guiding a portion of the analytical gas flow to the analysis section. Preferably, the portion of the analytical gas flow is resupplyed to the bypass line after the analysis section via a conduit. The angle at which the gas line guiding the portion of the analytical gas flow to the analysis section branches off is 10° to 170° with respect to the main flow direction. Through this gas guide, the portion of the particles not captured by the magnetic particle separation section, such as relatively heavy non-ferromagnetic particles, is guided through the bypass line and therefore does not adversely affect the gas analysis in the analysis section.

[0033] In another advantageous embodiment, the gas extraction device has a movable flap between the cooling section and the gas cleaning section. The flap is implemented as a grid with a mesh size of 0.5 mm to 3 mm. The flap is used for coarse separation of particulate material. The flap is provided with an actuator and is capable of moving from a closed position to an open cleaning position.

[0034] This objective is further achieved by a gas analysis device, wherein the analysis section has an optical gas analyzer, and the analysis section is widened in the region of the optical gas analyzer, wherein the widened portion is at least 100 mm, preferably at least 200 mm, and particularly preferably at least 300 mm. The required optical path length depends on the desired measurement range of the gas concentration.

[0035] Here, the widening is essentially done in only one dimension in order to maintain the volume of the gas extraction device and thus keep the dead time of the measurement low.

[0036] After analysis, the exhaust gas is returned to the exhaust gas pipeline through a return pipe that is connected to the exhaust gas pipeline. Attached Figure Description

[0037] The performance, features, and advantages of the present invention described above, as well as the methods and means of achieving them, become clearer and more apparent in conjunction with the following description of embodiments, which are explained in more detail with reference to the accompanying drawings. Hereinafter: Figure 1 A double-side view of an embodiment of an exhaust gas pipeline with a gas extraction device is shown. Figure 2 A bypass line for particle separation is shown. Figure 3 The magnetic particle separation section is shown. Detailed Implementation

[0038] Figure 1An embodiment of an exhaust gas pipeline 2 with a laterally arranged gas extraction device 1 is shown. The bi-lateral view shows the exhaust gas pipeline 2, the gas extraction device 1, which comprises an extraction pipe 3, a cooling section 4, a compensator 5, a gas cleaning section 6 with a magnet 15, an analysis section 7a with an integrated optical gas analyzer 7, a gas delivery unit 8, and a return pipe 9. Also shown are a movable flap 10 for coarse separation of particulate material, another movable flap 11, a cleaning pipe 12, a calibration gas flap 13, and a calibration gas inlet 14.

[0039] Hot exhaust gas loaded with particles is extracted from the exhaust gas stream through extraction pipe 3 and then passes through cooling section 6, compensator 5, and movable flap 10 for coarse separation. In cooling section 4, the exhaust gas stream, along with the particulate material contained therein, is cooled to such an extent that the particulate material becomes predominantly ferromagnetic. Compensator 5 compensates for the thermal expansion of gas extraction device 1 or decouples the mechanical vibration of exhaust gas line 2. In the subsequent gas cleaning section 6, the ferromagnetic particulate material in the gas stream, as well as other particulate material adhering to it, is predominantly adhered due to the applied magnetic field. Thus, the particulate loading of the exhaust gas is reduced to such an extent that the subsequently arranged optical gas analyzer 7 can perform measurements without problems. The required measurement path length of at least 100 mm is achieved by widening the flow channel in analysis section 7a. Here, the gas channel is designed to be compact and therefore to keep the measurement dead time low.

[0040] After the metallurgical process is completed, the particulate material can be removed from the gas cleaning section 6. To do this, the magnetic field is shut off, the movable flap 10 for coarse separation is opened, the movable flap 11 is closed, and gas is supplied through the cleaning pipe 12. As an alternative or supplement to the cleaning pipe 12, a striking device and / or a mechanical scraper can also be used. Thus, the particulate material is loosened and can be discharged back into the exhaust gas line under gravity support. Optionally, demagnetization of the ferromagnetic components can also be performed within the influence range of the magnetic particle separator.

[0041] Typically, the optical gas analyzer 7 can be calibrated after the metallurgical process is completed. To do this, the flap 13 is closed and calibration gas is introduced into the analysis section through the calibration gas inlet 14, so that the optical gas analyzer can perform the corresponding calibration.

[0042] Figure 2 A bypass line 20 is shown, which is oriented along the main flow direction of the dust-laden gas. A gas line is also shown that directs a portion of the analytical gas flow 21 to an analytical section that branches off from the main flow direction. The portion of the analytical gas flow is then resupplyed to the bypass line via a conduit after the analytical section.

[0043] Figure 3 A magnetic particle separation section is shown, wherein the magnet 25 is implemented as an electromagnet having a winding 26 and an iron core 27, wherein the core extension 28 guides the magnetic field close to the non-ferromagnetic wall 29 placed in the remaining wall region 30.

[0044] While the present invention has been illustrated and described in detail through preferred embodiments, the invention is not limited to the disclosed examples, and those skilled in the art can derive other variations therefrom without departing from the scope of protection of the invention.

[0045] List of reference numerals in the attached diagram: 1. Gas extraction equipment 2. Exhaust gas pipeline 3. Remove the tube 4 Cooling Section 5. Compensator 6. Gas Cleaning Section 7. Optical Gas Analyzer 7a Analysis Section 8 Gas delivery unit 9 return tubes 10 Movable flaps for coarse separation 11. Movable flip-up board 12 Cleaning tubes 13 Calibration Gas Flip Plate 14 Calibration Gas Inlet 15 Magnets 16 guide vanes 20 Bypass pipe 21 Partial Flow 25 Magnets 26 coils 27 Iron core 28 Core extension section 29 Nonferromagnetic materials 30. The remaining wall area.

Claims

1. A gas extraction device (1) for extracting hot, dust-laden gas from a waste gas pipeline (2) of a metallurgical facility, particularly an oxygen-blown converter or an electric arc furnace, wherein, The hot, dust-laden gas has ferromagnetic particulate material, wherein the extraction pipe (3) is arranged in the exhaust gas line (2) such that a portion of the gas flow is extracted, wherein, after the extraction pipe (3), the following is arranged: - Cooling section (4) for cooling the ferromagnetic particulate material to a temperature below 750°C; - Gas cleaning section (6); - Analysis section (7a); - Gas delivery unit (8); and - Return tube (9) The gas cleaning section (6) is characterized in that it has a magnetic particle separation section formed by a flat channel having a rectangular cross-section with an aspect ratio of less than 1:5, preferably less than 1:

10.

2. The gas extraction device (1) for extracting hot, dust-laden gas from a waste gas pipeline (2) of a metallurgical facility according to claim 1, characterized in that, The volume of gas flowing through the gas extraction device from the included extraction tube (3) to the included optical gas analyzer (7) is less than 0.3 m³. 3 Preferably less than 0.15 m 3 Preferred size is less than 0.05 m. 3 .

3. The gas extraction device (1) for extracting hot, dust-laden gas from the exhaust gas pipeline (2) of a metallurgical facility according to the preceding claims, characterized in that, The gas cleaning section (6) includes at least one guide vane (16) arranged such that the dust-laden gas is directed toward the magnetic particle separation section.

4. The gas extraction device (1) according to the preceding claims for extracting hot, dust-laden gas from the exhaust gas pipeline of a metallurgical facility, characterized in that, The gas cleaning section (6) has at least a portion of non-ferromagnetic material (29) in the wall region where the magnetic particle separation section is located and preferably has a smaller wall thickness than in the remaining wall regions (30), particularly preferably the smaller wall thickness should have a value of 1-10 mm, very particularly preferably a value of 1-5 mm.

5. The gas extraction device (1) according to the preceding claim for extracting hot, dust-laden gas from the exhaust gas pipeline of a metallurgical facility, characterized in that, An iron core extension (28) made of ferromagnetic material is arranged between the wall of the gas cleaning section (6) and the magnetic particle separation section, which guides the magnetic field close to the gas cleaning section (6).

6. The gas extraction device (1) for extracting hot, dust-laden gas from a waste gas pipeline of a metallurgical facility according to claim 5, characterized in that, The core extension (28) has a cooling device, preferably an air cooling device or a water cooling device.

7. The gas extraction device (1) according to any one of the preceding claims for extracting hot, dust-laden gas from a waste gas pipeline of a metallurgical facility, characterized in that, An electromagnet and / or a permanent magnet are present on at least one outer side of the flat channel, preferably on at least one wide side of the flat channel, wherein the electromagnet and / or the permanent magnet preferably has a cooling device, particularly preferably an air cooling device or a water cooling device.

8. The gas extraction device (1) according to the preceding claim, characterized in that, A cleaning device is arranged after the gas cleaning section (6), which includes: at least one cleaning pipe (12) for generating airflow and / or a scraper with a tapping device and / or a machine that removes separated particulate material from the gas cleaning section (6); and / or a gas supply section in the area between the analysis section and the gas delivery unit within the range of the sidewall of the flow channel; and / or a device for switching the pumping direction of the gas delivery unit; preferably additionally movable flaps (11) that guide the airflow mainly through the gas cleaning section (6) during the cleaning time.

9. The gas extraction device (1) according to the preceding claim, wherein, The gas delivery unit (8) is a fan or a jet pump.

10. The gas extraction device (1) according to the preceding claim, characterized in that, The analysis section (7a) is provided with a calibration gas flap (13) located upstream and at least one calibration gas inlet (14) for supplying calibration gas.

11. The gas extraction device (1) according to the preceding claim, characterized in that, A compensator (5) for compensating for thermal deformation and / or decoupling vibration is arranged between the cooling section (4) and the analysis section (7a), wherein the compensator is implemented, for example, as a bellows.

12. The gas extraction device (1) according to any one of the preceding claims, characterized in that, A bypass line (20) is arranged next to the analysis section (7a), wherein the bypass line (20) is oriented along the main flow direction of the dust-laden gas, and the gas line branches off a portion of the analytical gas flow (21) from the main flow direction and directs it to the analysis section (7a), and preferably, the portion of the analytical gas flow is resupplyed to the bypass line (20) after the analysis section (7a) by means of a line.

13. The gas extraction device (1) according to any one of the preceding claims, characterized in that, A movable flap (10) is arranged between the cooling section (4) and the gas cleaning section (6). The flap is implemented as a grid with a mesh size of 0.5 mm to 3 mm. The flap is used for coarse separation of particulate materials. The flap is provided with an actuator and is capable of moving from a closed position to an open cleaning position.

14. A gas analysis apparatus (1) comprising a gas extraction device (1) according to any one of the preceding claims, characterized in that, The analysis section (7a) has an optical gas analyzer (7), wherein the analysis section has a widened portion in the region of the optical gas analyzer, wherein the widened portion is at least 100 mm, preferably at least 200 mm, and particularly preferably at least 300 mm.

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