Plasma heating circulating device and method for furnace top gas

Abstract

The invention provides a plasma heating circulating device and method for furnace top gas. The plasma heating circulating device comprises a blast furnace, a treatment device and a plasma heating system. The plasma heating system at least comprises a group of heating devices, and each heating device is formed by combining a plasma heater and a power supply device; an inlet of the treatment device is connected with a furnace top gas outlet of the blast furnace; an outlet of the treatment device is connected with an inlet of the plasma heater; a graphite cathode and a graphite anode in the plasma heater are respectively connected with the power supply device, and an outlet of the plasma heater is connected with an inlet of the blast furnace through a tuyere of the blast furnace. Therefore, the furnace top gas generated by the blast furnace is purified and heated through the plasma heating circulating device, and is sprayed back to the blast furnace through the tuyere for recycling, so that the problem of carbon dioxide emission is solved, and meanwhile, the utilization rate of resources is also effectively improved.

Description

Technical Field

[0001] The present application relates to the technical field of iron and steel metallurgical processes, and in particular to a plasma heating circulation device and method for furnace top gas. Background Art

[0002] The total annual output of blast furnace gas, converter gas and coke oven gas in my country are all very high. These gases are rich in a large amount of carbon monoxide (CO) and hydrogen (H2). Among them, gases such as CO and H2 are mainly used for combustion, but the reduction characteristics of H2 and CO are not fully utilized, resulting in the ineffective utilization of their chemical energy, which is undoubtedly a waste of resources. Therefore, in order to avoid waste of resources, in the existing technology, it is necessary to first use a high reduction potential gas to heat H2 and CO, and then transfer the heated H2 and CO to the blast furnace for combustion, so as to achieve the purpose of fully utilizing the reduction characteristics of H2 and CO.

[0003] However, heating H2 and CO with high reducing potential gas will lead to increased carbon dioxide emissions, thus causing environmental pollution problems. Summary of the invention

[0004] Based on the above-mentioned deficiencies of the prior art, the present application provides a plasma heating circulation device and method for furnace top gas to solve the problem of environmental pollution caused by excessive emission of carbon dioxide.

[0005] In order to achieve the above objectives, this application provides the following technical solutions:

[0006] In a first aspect, the present application provides a plasma heating circulation device for furnace top gas, the plasma heating circulation device comprising: a blast furnace, a processing device and a plasma heating system;

[0007] The plasma heating system comprises at least one set of heating devices, which are composed of a plasma heater and a power supply device;

[0008] The inlet of the processing device is connected to the top gas outlet of the blast furnace, and the outlet of the processing device is connected to the inlet of the plasma heater. The processing device is used to pre-process the top gas generated by the blast furnace and transmit it to the plasma heating system;

[0009] The graphite cathode and the graphite anode in the plasma heater are respectively connected to the power supply device, the outlet of the plasma heater is connected to the inlet of the blast furnace through the tuyere of the blast furnace, the plasma heater is used to heat the pretreated top gas and ionize the heated top gas to obtain high-temperature plasma; the power supply device is used to provide energy to the plasma heater so that the plasma heater transmits the high-temperature plasma to the blast furnace through the tuyere.

[0010] Optionally, in the above-mentioned plasma heating circulation device for furnace top gas, the processing device includes: a gravity dust collector, a bag dust collector, and a pressurizer;

[0011] The inlet of the gravity dust collector is connected to the top gas outlet of the blast furnace, and the outlet of the gravity dust collector is connected to the inlet of the bag dust collector;

[0012] The outlet of the bag filter is connected to the inlet of the compressor;

[0013] The outlet of the pressurizer is connected to the inlet of the plasma heater.

[0014] Optionally, in the above-mentioned plasma heating circulation device for furnace top gas, the plasma heater is composed of a furnace shell, the graphite cathode, the graphite anode, a water-cooled copper sleeve, a reducing gas inlet, a reducing gas outlet and an arc zone combination;

[0015] One end of the graphite cathode and one end of the graphite anode are arranged in the cavity of the furnace shell, and one end of the graphite cathode is connected to one end of the graphite anode through the arc zone;

[0016] The other end of the graphite anode and the other end of the graphite cathode are fixed to both sides of the furnace shell through the water-cooled copper sleeve, and the other end of the graphite anode and the other end of the graphite cathode are respectively connected to the power supply device;

[0017] The reducing gas inlet is tangentially arranged on the lower surface of the furnace shell, and the reducing gas outlet is tangentially arranged on the upper surface of the furnace shell.

[0018] Optionally, in the above-mentioned plasma heating circulation device for furnace top gas, the inner lining of the furnace shell is composed of a combination of a heat-insulating layer and a working layer which are sequentially closely attached to the inner wall of the furnace shell.

[0019] Optionally, in the above-mentioned plasma heating circulation device for furnace top gas, the material of the thermal insulation layer of the furnace shell is a heat-insulating and wear-resistant material, and the material of the working layer of the furnace shell is a lightweight heat-insulating material.

[0020] Optionally, in the above-mentioned plasma heating circulation device for furnace top gas, the power supply device is a high-frequency DC power supply, and the high-frequency DC power supply is composed of a first rectifier, an inverter, a first transformer, a second rectifier and a smoothing reactor;

[0021] The input end of the first rectifier is connected to the graphite cathode of the plasma heater, and the output end of the first rectifier is connected to the input end of the inverter;

[0022] The input end of the first transformer is connected to the output end of the inverter, and the output end of the first transformer is connected to the input end of the second rectifier;

[0023] The input end of the smoothing reactor is connected to the output end of the second rectifier, and the output end of the smoothing reactor is connected to the graphite anode of the plasma heater.

[0024] Optionally, in the above-mentioned plasma heating circulation device for furnace top gas, the power supply device is a low-frequency DC power supply, and the low-frequency DC power supply is composed of a second transformer, a rectifier control cabinet, a thyristor rectifier and a reactor;

[0025] The input end of the second transformer is connected to the graphite cathode of the plasma heater, and the output end of the second transformer is respectively connected to the output end of the rectifier control cabinet and the input end of the thyristor rectifier;

[0026] The input end of the reactor is connected to the output end of the thyristor rectifier, and the output end of the reactor is connected to the graphite anode of the plasma heater.

[0027] Optionally, in the above-mentioned plasma heating circulation device for top gas, the volume range of the blast furnace is 450m 3 Up to 5000m 3 , and the number of tuyere arranged on the blast furnace ranges from 14 to 42.

[0028] The second aspect of the present application provides a plasma heating circulation method for furnace top gas, which is applied to a plasma heating circulation device for furnace top gas disclosed in the first aspect of the embodiment of the present application, and the method comprises:

[0029] Access to top gas produced by blast furnaces;

[0030] Pre-treating the furnace top gas by using a processing device to obtain high-pressure pure furnace top gas;

[0031] Using a plasma heater to perform plasma heating on the high-pressure pure furnace top gas to obtain highly reactive coal gas;

[0032] The highly reactive coal gas is conveyed back to the blast furnace.

[0033] Optionally, in the above-mentioned plasma heating circulation method for furnace top gas, the processing device includes a gravity dust collector, a bag dust collector, and a pressurizer, and the processing device is used to pre-treat the furnace top gas to obtain high-pressure pure furnace top gas, including:

[0034] Utilizing the gravity dust collector to perform dust removal treatment on the furnace top gas to obtain dust-removed furnace top gas;

[0035] Using the bag filter to perform fine dust removal on the dust-removed furnace top gas to obtain pure furnace top gas;

[0036] The pressurizing machine is used to pressurize the pure furnace top gas to obtain high-pressure pure furnace top gas.

[0037] The present application provides a plasma heating circulation device for top gas, which includes: a blast furnace, a processing device and a plasma heating system, the plasma heating system includes at least one set of heating devices, the heating device is composed of a plasma heater and a power supply device, the inlet of the processing device is connected to the top gas outlet of the blast furnace, the outlet of the processing device is connected to the inlet of the plasma heater, the processing device is used to pre-treat the top gas generated by the blast furnace and transmit it to the plasma heating system, the graphite cathode and the graphite anode in the plasma heater are respectively connected to the power supply device, the outlet of the plasma heater is connected to the inlet of the blast furnace through the tuyere of the blast furnace, the plasma heater is used to heat the pre-treated top gas, and ionize the heated top gas to obtain high-temperature plasma, the power supply device is used to provide energy to the plasma heater, so that the plasma heater transmits the high-temperature plasma to the blast furnace through the tuyere. Thus, the top gas generated by the blast furnace is purified and heated by the plasma heating circulation device, and is sprayed back into the blast furnace through the tuyere for recycling, thereby solving the problem of carbon dioxide emissions and effectively improving the utilization rate of resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0039] Figure 1 A first structural schematic diagram of a plasma heating circulation device for top gas provided in an embodiment of the present application;

[0040] Figure 2A second structural schematic diagram of a plasma heating circulation device for top gas provided in an embodiment of the present application;

[0041] Figure 3 A schematic diagram of the structure of a plasma heater provided in an embodiment of the present application;

[0042] Figure 4 A schematic diagram of the structure of a power supply device provided in an embodiment of the present application;

[0043] Figure 5 A schematic diagram of the structure of another power supply device provided in another embodiment of the present application;

[0044] Figure 6 A schematic flow chart of a plasma heating circulation method for furnace top gas provided in another embodiment of the present application;

[0045] Figure 7 A schematic flow chart of a method for pretreating top gas provided in another embodiment of the present application. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0047] In this application, relational terms such as first and second, etc. are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0048] As can be seen from the background technology, in the existing technology, the top gas is heated by using a high reducing potential gas before being input into the blast furnace. However, a large amount of carbon dioxide gas is emitted during the heating process, thereby causing environmental pollution.

[0049] Therefore, an embodiment of the present application provides a plasma heating circulation device for top gas, which includes a blast furnace, a processing device and a plasma heating system, so that before the top gas is input into the blast furnace, the top gas will be pretreated and plasma heated, thereby avoiding the generation of a large amount of carbon dioxide during the heating process, thereby solving the problem of environmental pollution.

[0050] So see Figure 1 , shows a first structural schematic diagram of a plasma heating circulation device for top gas provided in an embodiment of the present application, the plasma heating circulation device comprising: a blast furnace 1, a processing device 2 and a plasma heating system 3.

[0051] The plasma heating system 3 includes at least one set of heating devices 4 , and the heating devices 4 are composed of a plasma heater 5 and a power supply device 6 .

[0052] In some embodiments, the plasma heating system 3 may be composed of a plurality of plasma heaters 5 and a plurality of power supply devices 6, and one plasma heater 5 corresponds to one power supply device 6, so the total power range of the plasma heating system 3 is 80MW to 500MW. In addition, the plasma heating system 3 may also be composed of one plasma heater 5 and one power supply device 6, so the total power of the plasma heating system 3 is 100MW. Therefore, in the embodiment of the present application, the same number of plasma heaters 5 and power supply devices 6 may be selected according to the total power demand of the plasma heating system 3.

[0053] The inlet of the processing device 2 is connected to the top gas outlet of the blast furnace 1, and the outlet of the processing device 2 is connected to the inlet of the plasma heater 5. The processing device 2 is used to pre-treat the top gas generated by the blast furnace 1 and transmit it to the plasma heating system 3.

[0054] It is understandable that the amount of top gas produced by blast furnace 1 is 1300-1700 Nm 3 / t, gas temperature 80~180℃, gas pressure 0.15~0.3MPa, top gas 200~500Nm 3 / tExported to the gas network for other users, 1000~1400Nm 3 / tThe top gas is recycled as reducing gas. The composition of the top gas is shown in Table 1 below:

[0055] Table 1

[0056] <![CDATA[H2]]> CO <![CDATA[CO2]]> <![CDATA[O2]]> <![CDATA[N2]]> <![CDATA[H2O]]> Element% 1～5 40～55 35～50 0 2～5 1～4

[0057] It should be noted that the content of ingredients in Table 1 is only for illustration.

[0058] It should also be noted that since the top gas generated by the blast furnace 1 contains some impurities, which may affect the effect of the plasma heater 5, the top gas generated by the blast furnace 1 needs to be pretreated before heating it to remove impurities so as to meet the requirements for input into the plasma heater 5. Therefore, after the top gas is treated by the treatment device 2, the temperature of the top gas is 200-400°C, and the gas pressure is increased from the original 0.15-0.3MPa to 0.35-0.7MPa, thereby achieving the power required for gas circulation.

[0059] The graphite cathode 302 and the graphite anode 303 in the plasma heater 5 are respectively connected to the power supply device 6. The outlet of the plasma heater 5 is connected to the inlet of the blast furnace 1 through the tuyere 7 of the blast furnace 1. The plasma heater 5 is used to heat the pretreated furnace top gas and ionize the heated furnace top gas to obtain high-temperature plasma. The power supply device 6 is used to provide energy to the plasma heater 5 so that the plasma heater 5 transmits the high-temperature plasma to the blast furnace 1 through the tuyere 7.

[0060] It should be emphasized that a DC voltage is applied to the graphite cathode 302 and the graphite anode 303 in the plasma heater 5 through the power supply device 6, so that a high-temperature plasma is generated between the graphite cathode 302 and the graphite anode 303. When the pretreated top gas is input into the plasma heater 5, it will interact with the high-temperature plasma. At this time, the temperature of the pretreated top gas will be heated from 200°C to 400°C to 1800°C to 2400°C, and under the action of high temperature or a specific electromagnetic field, the CO2 gas molecules in the pretreated top gas can be partially or completely ionized to form plasma, and because the plasma has a high chemical activity, the CO2 molecules are activated and converted into active groups under the action of the plasma. These active groups are finally converted into stable carbon monoxide molecules CO through a series of reactions and input into the blast furnace 1 for recycling. The specific reaction equation is as follows:

[0061] ① In the plasma, CO2 first undergoes elastic or inelastic collision with high-energy electrons, and is excited and dissociated into CO molecules and active O atoms:

[0062] CO2+e*→CO+O+e (1)

[0063] CO2+e*→CO2*+e (2)

[0064] ②The generated active intermediate CO2* undergoes further reaction to generate reaction products:

[0065] CO2*+e*→CO+O (3)

[0066] O+O→O2 (4)

[0067] CO2+O→CO+O2 (5)

[0068] CO+O→CO2 (6)

[0069] Based on the above reaction equation, it can be understood that when the carbon dioxide molecule CO2 collides with the accelerated electron e*, it will decompose into carbon monoxide CO, producing a free oxygen atom O. The oxygen atom O is very active and can react with another oxygen atom O to form an oxygen molecule O2 or absorb oxygen from the carbon dioxide molecule CO2 to promote the decomposition of CO2. Therefore, CO will be generated after the chemical reactions (1), (3) and (5). The overall conversion rate of CO2 is 2% to 20%. The main reason for the low CO2 conversion rate is the existence of reaction (6).

[0070] Therefore, the mixed gas composition of the furnace top gas after heating and ionization can be seen in the following Table 2:

[0071] Table 2

[0072]

[0073]

[0074] The mixed gas composition of the furnace top gas in Table 2 is only used for illustration.

[0075] It should also be emphasized that when there are multiple plasma heaters 5, the temperature of the furnace top gas will be heated from 200°C to 400°C to 1800°C to 2400°C, and when there is only one plasma heater 5, the temperature of the furnace top gas will be heated from 300°C to 2200°C.

[0076] It should be noted that the tuyere 7 of the blast furnace 1 is connected to the blast furnace 1, so after the plasma heater 5 heats and ionizes the furnace top gas, the plasma heater 5 will spray the treated furnace top gas into the blast furnace 1 through the tuyere 7 of the blast furnace 1. Among them, using the tuyere 7 instead of hot air and coal powder can reduce coke consumption and reduce carbon emissions. It should also be noted that after the high-temperature furnace top gas rich in CO is sprayed into the blast furnace 1, it will pass through the tuyere whirlpool area and quickly undergo an indirect reduction reaction with iron oxides, which can effectively improve the indirect reduction rate, and the blast furnace 1 does not need to be blown into hot air, oxygen or coal powder and other reducing agents, and can replace part of the coke, further reducing the coke consumption from 350kg / t to 290kg / t, and also reducing the total CO2 emissions of the ironmaking process.

[0077] In some embodiments, the volume range of blast furnace 1 is 450m 3 Up to 5000m 3, and the number of tuyere 7 arranged on the blast furnace 1 ranges from 14 to 42.

[0078] In addition, the tuyere 7 is evenly distributed at the lower part of the furnace belly of the blast furnace 1 along the furnace shell of the blast furnace 1 , and evenly distributed at the upper part of the furnace hearth of the blast furnace 1 .

[0079] In the embodiment of the present application, the top gas generated by the blast furnace can be pretreated, heated and ionized through a blast furnace, a processing device and a plasma heating system, and then sprayed into the blast furnace through the blast furnace tuyere for recycling. There is no need to blow a reducing agent into the blast furnace, thereby effectively solving the environmental pollution problem.

[0080] In some embodiments, in combination Figure 1 , see Figure 2 , shows a second structural schematic diagram of a plasma heating circulation device for furnace top gas, the processing device 2 includes: a gravity dust collector 200, a bag dust collector 201, and a pressurizer 202.

[0081] The inlet of the gravity dust collector 200 is connected to the top gas outlet of the blast furnace 1 , and the outlet of the gravity dust collector 200 is connected to the inlet of the bag dust collector 201 .

[0082] The outlet of the bag filter 201 is connected to the inlet of the compressor 202 .

[0083] The outlet of the pressurizer 202 is connected to the inlet of the plasma heater 5 .

[0084] It can be understood that the top gas generated by the blast furnace 1 will first be subjected to preliminary dust removal treatment in the gravity dust collector 200, and then the top gas after preliminary dust removal treatment will be input into the bag filter 201 for fine dust removal treatment. At this time, the dust concentration in the top gas filtered by the bag filter 201 will be less than 5mg / Nm3, and finally the top gas after fine dust removal treatment will be input into the compressor 202 for pressurization treatment, thereby providing power for the gas circulation. Therefore, based on this description, it can be seen that the gravity dust collector 200 is used to remove dust from the top gas and realize preliminary purification of the gas. The bag filter 201 is used to further collect fine dust particles from the top gas to realize fine dust removal of the gas. The compressor 202 is used to pressurize the top gas.

[0085] In some embodiments, the processing capacity of the press 202 is 110,000 Nm 3 / h.

[0086] In the embodiment of the present application, the purpose of purifying the furnace top gas can be achieved through the processing device, thereby improving the utilization efficiency and safety of the furnace top gas and reducing pollution to the environment.

[0087] In some embodiments, see Figure 3, shows a schematic structural diagram of a plasma heater, the plasma heater 5 is composed of a furnace shell 301, a graphite cathode 302, a graphite anode 303, a water-cooled copper sleeve 304, a reducing gas inlet 305, a reducing gas outlet 306 and an arc zone 307.

[0088] One end of a graphite cathode 302 and one end of a graphite anode 303 are disposed in the cavity of the furnace shell 301 , and one end of the graphite cathode 302 is connected to one end of the graphite anode 303 through an arc zone 307 .

[0089] In some embodiments, the furnace shell 301 is made of steel plate, wherein the type of the steel plate is 15CrMoR, and of course it may be other types of steel plates, and the embodiments of the present application are not limited to this signal.

[0090] It should be noted that the heat treatment method of the plasma heater 5 in the embodiment of the present application adopts the normalizing + tempering method, which can improve the overall performance of the plasma heater 5, including mechanical properties, structural stability and wear resistance, thereby improving the service life of the plasma heater 5. Therefore, in some embodiments, the lining of the furnace shell 301 of the plasma heater 5 is composed of an insulation layer 308 and a working layer 309 which are tightly attached to the inner wall of the furnace shell 301 in sequence.

[0091] In some embodiments, the insulation layer of the furnace shell 301 is made of a heat-insulating and wear-resistant material with a thickness of 200 mm, and the working layer of the furnace shell 301 is made of a lightweight heat-insulating material with a thickness of 250 mm, thereby not only improving the thermal efficiency and safety of the furnace shell 301, but also extending its service life, optimizing temperature control, and enhancing the stability and reliability of the overall structure.

[0092] The other end of the graphite anode 303 and the other end of the graphite cathode 302 are fixed to both sides of the furnace shell 301 through a water-cooled copper sleeve 304, and the other end of the graphite anode 303 and the other end of the graphite cathode 302 are respectively connected to the power supply device 6.

[0093] Specifically, the other end of the graphite anode 303 and the other end of the graphite cathode 302 are fixed on both sides of the furnace shell 301 by the water-cooled copper sleeve 304, so that the water-cooled copper sleeve 304 can effectively take away the heat generated by the graphite cathode 302 and the graphite anode 303 during operation to prevent them from overheating, and ensure that the electrodes operate within a suitable temperature range, thereby improving their service life and performance. In addition, copper has excellent electrical conductivity. The design of the water-cooled copper sleeve 304 not only provides good mechanical support, but also optimizes the conduction of current, makes the current evenly distributed on the electrode, and enhances the working efficiency of the electrode. At the same time, the cooling effect of the water-cooled copper sleeve 304 can reduce the thermal stress caused by temperature changes, reduce the fatigue and crack risks of the electrode material, and ensure the long-term stability of the electrode.

[0094] In addition, the other end of the graphite anode 303 and the other end of the graphite cathode 302 are respectively connected to the power supply device 6, so that the power supply device 6 can provide energy to the plasma heater 5, so that high-temperature plasma is generated between the graphite anode 303 and the graphite cathode 302 to react with the furnace top gas, thereby achieving the purpose of ionization of the furnace top gas.

[0095] The reducing gas inlet 305 is tangentially arranged on the lower surface of the furnace shell 301 , and the reducing gas outlet 306 is tangentially arranged on the upper surface of the furnace shell 301 .

[0096] It should be noted that the reducing gas inlet 305 and the reducing gas outlet 306 are arranged tangentially to the furnace shell 301, which can play a swirling role, increase the residence time of the gas generated in the reaction process, thereby improving the heat exchange efficiency, and when the reducing gas is heated and ionized by the arc zone 307 between the graphite anode 303 and the graphite cathode 302, it can be directly discharged out of the furnace shell 301 through the reducing gas outlet 306.

[0097] In the implementation of the present application, the top gas is heated and ionized by a plasma heater to obtain a high-temperature plasma, wherein the high-temperature plasma can promote the chemical reaction, decompose carbon dioxide and produce carbon monoxide, thereby increasing the carbon monoxide content in the top gas to be used as the combustion gas of the blast furnace 1, thereby achieving the purpose of recycling and reducing environmental pollution.

[0098] In some embodiments, see Figure 4 , shows a schematic diagram of the structure of a power supply device, the power supply device 6 is a high-frequency DC power supply 400, and the high-frequency DC power supply 400 is composed of a first rectifier 401, an inverter 402, a first transformer 403, a second rectifier 404 and a smoothing reactor 405.

[0099] An input end of the first rectifier 401 is connected to the graphite cathode 302 of the plasma heater 5 , and an output end of the first rectifier 401 is connected to an input end of the inverter 402 .

[0100] An input end of the first transformer 403 is connected to an output end of the inverter 402 , and an output end of the first transformer 403 is connected to an input end of the second rectifier 404 .

[0101] An input end of the smoothing reactor 405 is connected to an output end of the second rectifier 404 , and an output end of the smoothing reactor 405 is connected to the graphite anode 303 of the plasma heater 5 .

[0102] It should be noted that the high-frequency DC power supply 400 provides a DC voltage for the plasma heater 5. The specific working principle is that the three-phase AC power is rectified by the first rectifier 401 to become DC power, which is then inverted into a 20kHz~25kHz AC voltage by the full-bridge inverter 402, and then transformed and matched by the first transformer 403, and then rectified into a 40kHz~50kHz DC voltage by the second rectifier 404, and finally filtered by the smoothing inductor 405, so as to provide a DC voltage for the graphite anode 303 and the graphite cathode 302.

[0103] In some embodiments, the first rectifier 401 is a full-bridge rectifier, the inverter 402 is an IGBT inverter, that is, an insulated gate bipolar transistor (Insulated Gate Bipolar Transistor), the first transformer 403 is a high-frequency isolation transformer, and the second rectifier 404 is a Schottky diode rectifier.

[0104] In the embodiment of the present application, the high-frequency DC power supply can reduce the generation of harmonics and improve the quality of electric energy through effective control and design, thereby providing energy to the plasma heater 5 with high efficiency and quality.

[0105] In some embodiments, see Figure 5 , shows a schematic diagram of the structure of another power supply device, the power supply device 6 is a low-frequency DC power supply 500, and the low-frequency DC power supply 500 is composed of a second transformer 501, a rectifier control cabinet 502, a thyristor rectifier 503 and an inductor 504.

[0106] The input end of the second transformer 501 is connected to the graphite cathode 302 of the plasma heater 5 , and the output end of the second transformer 501 is connected to the output end of the rectifier control cabinet 502 and the input end of the thyristor rectifier 503 , respectively.

[0107] An input end of the reactor 504 is connected to an output end of the thyristor rectifier 503 , and an output end of the reactor 504 is connected to the graphite anode 303 of the plasma heater 5 .

[0108] It should be noted that the low-frequency DC power supply 500 provides a DC voltage for the plasma heater 5. The specific working principle is that the high-voltage AC power is stepped down by the second transformer 501 to become a low-voltage AC power suitable for rectification, and then the low-voltage AC power is input to the rectifier control cabinet 502. The signal sent by the control cabinet controls the conduction timing of the thyristor rectifier 503 to complete the rectification and convert the AC power into a DC voltage. Finally, the rectified DC voltage is filtered by the inductor 504 to smooth the current output and ensure current stability and power quality.

[0109] In the embodiment of the present application, a stable DC voltage can be outputted by a low-frequency DC power supply and transmitted to the plasma heater to meet the high-power power supply requirement of the plasma heater.

[0110] The present application provides a plasma heating circulation device for top gas, which includes: a blast furnace, a processing device and a plasma heating system, the plasma heating system includes at least one set of heating devices, the heating device is composed of a plasma heater and a power supply device, the inlet of the processing device is connected to the top gas outlet of the blast furnace, the outlet of the processing device is connected to the inlet of the plasma heater, the processing device is used to pre-treat the top gas generated by the blast furnace and transmit it to the plasma heating system, the graphite cathode and the graphite anode in the plasma heater are respectively connected to the power supply device, the outlet of the plasma heater is connected to the inlet of the blast furnace through the tuyere of the blast furnace, the plasma heater is used to heat the pre-treated top gas, and ionize the heated top gas to obtain high-temperature plasma, the power supply device is used to provide energy to the plasma heater, so that the plasma heater transmits the high-temperature plasma to the blast furnace through the tuyere. Thus, the top gas generated by the blast furnace is purified and heated by the plasma heating circulation device, and is sprayed back into the blast furnace through the tuyere for recycling, thereby solving the problem of carbon dioxide emissions and effectively improving the utilization rate of resources.

[0111] A plasma heating circulation device for furnace top gas provided in the above-mentioned embodiment of the present application, see Figure 6 , shows a flow chart of a plasma heating circulation method for furnace top gas provided in an embodiment of the present application, the method comprising:

[0112] S601. Obtain top gas generated by a blast furnace.

[0113] Specifically, in order to improve the utilization efficiency of secondary energy in the steel production process, reduce the emission pressure of steel enterprises, achieve optimal energy benefits, and thus achieve the goals of carbon reduction and cost reduction, the top gas produced by the blast furnace will be recycled. However, in order to give full play to the reducing characteristics of the gas contained in the top gas, it is necessary to collect the top gas produced by the blast furnace first.

[0114] S602: pre-treat the furnace top gas using a processing device to obtain high-pressure pure furnace top gas.

[0115] It should be noted that after obtaining the top gas produced by the blast furnace, the top gas needs to be pretreated to remove impurities in the top gas, thereby reducing pollutant emissions in the subsequent combustion process and meeting environmental protection requirements.

[0116] It should also be noted that high-pressure pure top gas can maintain more stable combustion characteristics in the future, reduce possible fluctuations in the production process, and improve the stability and safety of the plasma heater during processing.

[0117] Optionally, in another embodiment of the present application, the processing device includes a gravity dust collector, a bag dust collector, and a pressurizing machine, and a specific implementation of step S602 is as follows: Figure 7 As shown, the following steps are included:

[0118] S701. Use a gravity dust collector to remove dust from the furnace top gas to obtain dust-removed furnace top gas.

[0119] Specifically, the gravity dust collector mainly removes large particles of dust from the furnace top gas to achieve the effect of preliminary purification of the furnace top gas.

[0120] S702, using a bag filter to perform fine dust removal on the dust-removing furnace top gas to obtain pure furnace top gas.

[0121] It should be noted that since the gravity dust collector can only remove large particles of dust, and the dust removal efficiency is 30% to 70%, it is unable to achieve the purpose of fine dust removal. Therefore, after the initial dust removal using the gravity dust collector, it is also necessary to use a bag dust collector to remove fine particles of dust from the dust-removing furnace top gas in order to obtain clean, dust-free furnace top gas.

[0122] S703, pressurizing the pure furnace top gas by using a compressor to obtain high-pressure pure furnace top gas.

[0123] It is understandable that after the top gas is finely dusted, it is also necessary to pressurize the top gas so that the pressure of the top gas can reach the power required for circulation, so that the subsequent plasma heater can rely on the pressure of the top gas and spray the top gas into the blast furnace through the tuyere.

[0124] S603, using a plasma heater to perform plasma heating on the high-pressure pure furnace top gas to obtain highly reactive coal gas.

[0125] It should be noted that after obtaining the high-pressure pure top gas, the high-pressure pure top gas is input into the plasma heater for heating, so that under the action of the plasma heater, the CO2 molecules in the high-pressure pure top gas are dissociated and ionized, thereby converting part of the CO2 molecules into active particles to obtain highly reactive coal gas.

[0126] S604, transport the highly reactive coal gas back to the blast furnace.

[0127] Specifically, after obtaining the highly reactive coal gas, the highly reactive coal gas can be transmitted back to the blast furnace through the tuyere to achieve the effect of recycling the top coal gas. In this process, there is no large-scale emission of carbon dioxide, thus effectively solving the problem of environmental pollution caused by large-scale emission of carbon dioxide.

[0128] The present application provides a plasma heating circulation method for furnace top gas, which obtains furnace top gas generated by a blast furnace, and then pre-treats the furnace top gas using a processing device to obtain high-pressure pure furnace top gas, and then uses a plasma heater to plasma heat the high-pressure pure furnace top gas to obtain highly reactive coal gas, and finally transmits the highly reactive coal gas back to the blast furnace. Thus, the plasma heater fully and effectively exerts the reduction characteristics of the gas contained in the furnace top gas, and also effectively solves the problem of large-scale carbon dioxide emissions, thereby achieving the purpose of protecting the environment.

[0129] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0130] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A plasma heating circulation device for furnace top gas, characterized in that: The plasma heating circulation device comprises: a blast furnace, a processing device and a plasma heating system; The plasma heating system comprises at least one set of heating devices, which are composed of a plasma heater and a power supply device; The inlet of the processing device is connected to the top gas outlet of the blast furnace, and the outlet of the processing device is connected to the inlet of the plasma heater. The processing device is used to pre-process the top gas generated by the blast furnace and transmit it to the plasma heating system; The graphite cathode and the graphite anode in the plasma heater are respectively connected to the power supply device, the outlet of the plasma heater is connected to the inlet of the blast furnace through the tuyere of the blast furnace, the plasma heater is used to heat the pretreated top gas and ionize the heated top gas to obtain high-temperature plasma; the power supply device is used to provide energy to the plasma heater so that the plasma heater transmits the high-temperature plasma to the blast furnace through the tuyere.

2. The plasma heating circulation device according to claim 1, characterized in that: The processing device includes: a gravity dust collector, a bag dust collector, and a pressurizer; The inlet of the gravity dust collector is connected to the top gas outlet of the blast furnace, and the outlet of the gravity dust collector is connected to the inlet of the bag dust collector; The outlet of the bag filter is connected to the inlet of the compressor; The outlet of the pressurizer is connected to the inlet of the plasma heater.

3. The plasma heating circulation device according to claim 1, characterized in that: The plasma heater is composed of a furnace shell, the graphite cathode, the graphite anode, a water-cooled copper sleeve, a reducing gas inlet, a reducing gas outlet and an arc zone; One end of the graphite cathode and one end of the graphite anode are arranged in the cavity of the furnace shell, and one end of the graphite cathode is connected to one end of the graphite anode through the arc zone; The other end of the graphite anode and the other end of the graphite cathode are fixed to both sides of the furnace shell through the water-cooled copper sleeve, and the other end of the graphite anode and the other end of the graphite cathode are respectively connected to the power supply device; The reducing gas inlet is tangentially arranged on the lower surface of the furnace shell, and the reducing gas outlet is tangentially arranged on the upper surface of the furnace shell.

4. The plasma heating circulation device according to claim 3, characterized in that: The inner lining of the furnace shell is composed of a thermal insulation layer and a working layer which are sequentially closely attached to the inner wall of the furnace shell.

5. The plasma heating circulation device according to claim 3, characterized in that: The material of the heat-insulating layer of the furnace shell is a heat-insulating and wear-resistant material, and the material of the working layer of the furnace shell is a light heat-insulating material.

6. The plasma heating circulation device according to claim 1, characterized in that: The power supply device is a high-frequency DC power supply, which is composed of a first rectifier, an inverter, a first transformer, a second rectifier and a smoothing reactor; The input end of the first rectifier is connected to the graphite cathode of the plasma heater, and the output end of the first rectifier is connected to the input end of the inverter; The input end of the first transformer is connected to the output end of the inverter, and the output end of the first transformer is connected to the input end of the second rectifier; The input end of the smoothing reactor is connected to the output end of the second rectifier, and the output end of the smoothing reactor is connected to the graphite anode of the plasma heater.

7. The plasma heating circulation device according to claim 1, characterized in that: The power supply device is a low-frequency DC power supply, which is composed of a second transformer, a rectifier control cabinet, a thyristor rectifier and a reactor; The input end of the second transformer is connected to the graphite cathode of the plasma heater, and the output end of the second transformer is respectively connected to the output end of the rectifier control cabinet and the input end of the thyristor rectifier; The input end of the reactor is connected to the output end of the thyristor rectifier, and the output end of the reactor is connected to the graphite anode of the plasma heater.

8. The plasma heating circulation device according to claim 1, characterized in that: The volume range of the blast furnace is 450m 3 Up to 5000m 3 , and the number of tuyere arranged on the blast furnace ranges from 14 to 42.

9. A plasma heating circulation method for furnace top gas, characterized in that: A plasma heating circulation device for furnace top gas as described in any one of claims 1 to 8, the method comprising: Access to top gas produced by blast furnaces; Pre-treating the furnace top gas by using a processing device to obtain high-pressure pure furnace top gas; Using a plasma heater to perform plasma heating on the high-pressure pure furnace top gas to obtain highly reactive coal gas; The highly reactive coal gas is conveyed back to the blast furnace.

10. The method according to claim 9, characterized in that The processing device includes a gravity dust collector, a bag dust collector, and a pressurizer. The processing device is used to pre-treat the furnace top gas to obtain high-pressure pure furnace top gas, including: Utilizing the gravity dust collector to perform dust removal treatment on the furnace top gas to obtain dust-removed furnace top gas; Using the bag filter to perform fine dust removal on the dust-removed furnace top gas to obtain pure furnace top gas; The pressurizing machine is used to pressurize the pure furnace top gas to obtain high-pressure pure furnace top gas.

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