Energy-saving system and method for recovering combustible components of furnace gas from submerged arc furnace

Abstract

The present invention relates to the technical field of recovering furnace gas from an ore-heating furnace, and is an energy-saving system for recovering combustible components of furnace gas from an ore-heating furnace, wherein the starting end of a furnace gas pipeline is arranged inside the ore-heating furnace, the mixed combustion nozzle is butted with the end of the furnace gas pipeline, and the mixed combustion nozzle is placed in a rotary kiln; the cyclone, cooler and filter assembly are sequentially arranged between the starting end and the end of the furnace gas pipeline; the cyclone is used to separate dust with a particle size greater than 5 μm in the furnace gas; the cooler is used to cool the furnace gas; the filter assembly is used to filter dust with a particle size greater than 0.3 μm in the furnace gas; the furnace gas pipeline is used to recover combustible gas in the ore-heating furnace and ignite it in a rotary kiln through the mixed combustion nozzle, and the energy-saving system can realize the mixed combustion of gas-solid two-phase fuel in the rotary kiln, thereby realizing the recovery and reuse of furnace gas from an ore-heating furnace. The present invention also proposes an energy-saving method for recovering combustible components of furnace gas from an ore-heating furnace.

Description

Technical Field

[0001] The invention relates to the technical field of recovering furnace gas from an ore-fired furnace, and in particular to an energy-saving system and method for recovering combustible components of furnace gas from an ore-fired furnace. Background Art

[0002] The Rotary Kiln-Electiric Furnace process has been widely used in nickel-iron smelting process due to its advantages such as easy control of nickel-iron grade, high productivity and mature process technology. The RKEF process also has problems such as high energy consumption and high emissions that restrict its own development. In addition, the thermal efficiency of industrial furnaces is generally lower than 70%, and its exhaust gas accounts for more than 25% of the total energy consumption. If these exhaust gases are utilized, there will be great energy-saving potential. At present, it is relatively difficult to recycle coal gas from submerged arc furnaces in the metallurgical industry. The general recycling methods mainly include gas boiler power generation, gas boiler and waste heat boiler combined power generation, flue gas collection, storage and reuse. However, the traditional recovery process is difficult to implement due to its high cost, great safety hazards and little benefit.

[0003] The mixed combustion nozzle in the rotary kiln is the core equipment for achieving the mixed combustion of pulverized coal and combustible gases such as CO. It plays a key role in reducing the energy consumption of the rotary kiln, improving the roasting rate of ore materials, extending the life of the kiln body, and reducing harmful gas emissions. With the development of combustion technology and the innovation of manufacturing technology, new burners are emerging in an endless stream. From the initial single-channel burner to the multi-channel burner. The multi-channel burner in the existing technology does not mix the fuel particles with oxygen sufficiently, the flame stability is insufficient, and the gas-solid fuel mixed combustion rate is low, so the overall combustion efficiency is unstable. Summary of the invention

[0004] In order to solve the above problems, the present invention proposes an energy-saving system for recovering combustible components of furnace gas from an ore-fired furnace, which can realize mixed combustion of gas-solid two-phase fuel in a rotary kiln, thereby realizing the recovery and reuse of furnace gas from an ore-fired furnace. The present invention also proposes an energy-saving method for recovering combustible components of furnace gas from an ore-fired furnace.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] In the first technical solution, an energy-saving system for recovering combustible components of furnace gas from an ore-fired furnace comprises a furnace gas pipeline, a cyclone, a cooler, a filter assembly and a mixed burner, wherein the starting end of the furnace gas pipeline is arranged inside the ore-fired furnace, the end of the furnace gas pipeline is connected to the mixed burner, the mixed burner is placed in a rotary kiln, and the cyclone, the cooler and the filter assembly are arranged in sequence between the starting end and the end of the furnace gas pipeline;

[0007] The cyclone is used to separate dust with a particle size greater than 5 μm in the furnace gas;

[0008] The cooler is used to cool the furnace gas;

[0009] The filter assembly is used to filter dust with a particle size greater than 0.3 μm in the furnace gas;

[0010] The furnace gas pipeline is used to recover the combustible gas in the ore-fired furnace and ignite it in the rotary kiln through the mixed combustion nozzle.

[0011] In the first technical solution, preferably, a water cooling pipe for rapid pre-cooling of the furnace gas is provided at the beginning of the furnace gas pipe.

[0012] In the first technical solution, preferably, in the furnace gas pipeline, a first relief valve, a first air supply valve and a first control unit of a DCS distributed control system are sequentially provided between the starting end of the furnace gas pipeline and the input end of the cyclone.

[0013] In the first technical solution, preferably, in the furnace gas pipeline, a second control unit of a DCS distributed control system is provided between the gas output end of the cyclone and the input end of the cooler.

[0014] In the first technical solution, preferably, in the furnace gas pipeline, a rough blower and a third control unit of a DCS distributed control system are provided between the output end of the cooler and the input end of the filter assembly.

[0015] In the first technical solution, preferably, a clean air blower for pressurizing the furnace gas is provided between the output end of the filter assembly and the end of the furnace gas pipeline, and a fourth control unit of the DCS distributed control system is provided between the output end of the filter assembly and the clean air blower.

[0016] In the first technical solution, preferably, a fifth control unit of a DCS distributed control system, a second relief valve and a second air supply valve are provided in sequence between the output end of the clean air blower and the end of the furnace gas pipeline.

[0017] In the first technical scheme, as a preference, the mixed burner includes a pulverized coal air channel, a furnace gas air channel, a compressed air channel, a diesel channel, a central wind channel, a first flange, a swirl wind channel, a second flange, a third flange, an axial flow wind channel, an air swirler and an outlet disc, wherein the main body of the mixed burner is 6 layers of concentrically arranged pipes, the air swirler is arranged at the outlet end of the main body of the mixed burner, and 6 layers of cavities are formed in the 6 layers of concentric pipes of the main body of the mixed burner, the outermost cavity of the main body of the mixed burner is connected to the axial flow wind channel, the second outermost cavity of the mixed burner is connected to the swirl wind channel, the third outermost cavity of the mixed burner is connected to the pulverized coal air channel, the fourth outermost cavity of the mixed burner is connected to the furnace gas pipeline, the fifth outermost cavity of the mixed burner is connected to the central wind channel, the innermost cavity of the mixed burner is connected to the diesel channel, and the compressed air channel is connected to the innermost cavity of the mixed burner.

[0018] The central air channel, the swirl air channel and the axial air channel all have air passing therethrough for conveying combustion-supporting air to the mixed combustion nozzle;

[0019] The pulverized coal air channel is connected to the pulverized coal pipeline and is used to transport pulverized coal particles into the mixed combustion nozzle;

[0020] The furnace gas wind channel is communicated with the end of the furnace gas pipeline and is used for conveying purified furnace gas to the mixed combustion nozzle.

[0021] In the second technical solution, an energy-saving method for recovering combustible components of furnace gas from an ore-fired furnace, using an energy-saving system for recovering combustible components of furnace gas from an ore-fired furnace as described in any one of the first technical solutions, comprises the following steps:

[0022] Step 1: After the furnace gas from the submerged arc furnace leaves the furnace cover, it enters the water cooling pipe of the purification device for rapid pre-cooling treatment;

[0023] Step 2: The pre-cooled furnace gas enters the cyclone, and the dust with a particle size greater than 5 μm is separated from the airflow by the inertial force of the dust and the centrifugal force generated by the rotation of the dust-laden airflow, thus achieving gas-solid separation;

[0024] Step 3: The separated furnace gas enters the cooler and rough fan, so that the furnace gas can reach the temperature requirements of the subsequent filter to avoid unnecessary damage to subsequent equipment;

[0025] Step 4: The cooled furnace gas enters the filter assembly, and the dust with a particle size greater than 0.3 μm is filtered and collected one by one;

[0026] Step 5: The dust-removed furnace gas enters the clean gas blower and is transported to the furnace gas air channel of the mixed combustion nozzle in the rotary kiln after being pressurized, completing the recovery and purification of the furnace gas of the ore-fired furnace.

[0027] Step 6: The DCS distributed control system sends data to the centralized control center based on the furnace gas flow rate and the content of combustible components such as CO, adjusts the supply of furnace gas and pulverized coal fuel in real time, and optimizes the gas-solid fuel mixing ratio.

[0028] The beneficial effects of using the present invention are:

[0029] 1. The energy-saving system for recovering the combustible components of the furnace gas of the submerged arc furnace in the present invention recovers CO gas in the furnace gas of the submerged arc furnace through the furnace gas pipeline. The CO gas is a combustible gas. The method purifies, recovers and pressurizes the furnace gas of the submerged arc furnace and inputs the CO gas into the rotary kiln to realize the recovery and reuse of the combustible gas in the furnace gas of the submerged arc furnace, that is, to avoid the pollution caused by the discharge of the furnace gas of the submerged arc furnace into the environment, and can also reduce the energy consumption of the rotary kiln.

[0030] 2. The present invention designs a six-channel mixed burner at the end of an energy-saving system for recovering combustible components of furnace gas from an electric arc furnace. The recycled furnace gas is mixed with pulverized coal in a certain proportion and then introduced into a rotary kiln for ignition, thereby achieving mixed combustion of pulverized coal and combustible gases such as CO in the rotary kiln. The mixed burner delivers air, combustible gas fuels such as CO and pulverized coal into the rotary kiln in the order of central wind, combustible gas fuels such as CO, pulverized coal fuel, swirl wind and axial wind. The swirl wind increases the diffusivity of pulverized coal particles, and the flammability of the gas fuel increases the combustion rate of the pulverized coal fuel. Compared with pure pulverized coal fuel, the addition of gas fuel not only helps to improve the pulverized coal combustion rate and the temperature distribution in the kiln, but also reduces the emission of harmful substances such as sulfides, and improves the problem of over-sintering or under-sintering caused by the combustion of pure pulverized coal.

[0031] 3. The present invention utilizes the DCS distributed control system set in the energy-saving system for recovering the combustible components of the furnace gas of the ore-fired furnace, which can detect the flow rate and component content of the recovered furnace gas, regulate the supply of furnace gas and coal powder, send data to the centralized control center, adjust the supply of furnace gas and coal powder fuel in real time, optimize the gas-solid fuel mixing ratio, facilitate flame control, and ultimately achieve the effect of flame stable combustion. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the energy-saving system for recovering combustible components of furnace gas of an electric arc furnace according to the present invention.

[0033] Figure 2 It is a schematic diagram of a mixed burner in the energy-saving system for recovering combustible components of furnace gas of an ore-fired furnace according to the present invention.

[0034] Reference numerals include:

[0035] Submerged arc furnace, 2-furnace gas pipeline, 3-first relief valve, 4-first air supply valve, 5-DCS distributed control system first control unit, 6-cyclone, 7-DCS distributed control system second control unit, 8-cooler, 9-rough fan, 10-DCS distributed control system third control unit, 11-first filter, 12-second filter, 13-DCS distributed control system fourth control unit, 14-clean air fan, 15-DCS distributed control system fifth control unit, 16-second relief valve, 17-second air supply valve, 18-mixed combustion nozzle, 19-rotary kiln, 20-coal powder air channel, 21-furnace gas air channel, 22-compressed air channel, 23-diesel channel, 24-central air channel, 25-first flange, 26-swirl air channel, 27-second flange, 28-third flange, 29-axial flow air channel, 30-air cyclone, 31-exit disc. DETAILED DESCRIPTION

[0036] In order to make the purpose and advantages of the technical solution more clear, the technical solution is further described in detail below in conjunction with specific implementation methods. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the technical solution.

[0037] like Figure 1 As shown, an energy-saving system for recovering combustible components in furnace gas of an ore-heating furnace 1 comprises a furnace gas pipeline 2, a cyclone 6, a cooler 8, a filter assembly and a mixed burner 18, wherein the starting end of the furnace gas pipeline 2 is arranged inside the ore-heating furnace 1, the mixed burner 18 is butt-jointed with the end of the furnace gas pipeline 2, the mixed burner 18 is placed in a rotary kiln 19, the cyclone 6, the cooler 8 and the first filter 11 and the second filter 12 are sequentially arranged between the starting end and the end of the furnace gas pipeline 2; the cyclone 6 is used to separate dust with a particle size greater than 5 μm in the furnace gas; the cooler 8 is used to cool the furnace gas; the filter assemblies 11 and 12 are used to filter dust with a particle size greater than 0.3 μm in the furnace gas; the furnace gas pipeline 2 is used to recover the combustible gas in the ore-heating furnace 1 and ignite it in the rotary kiln 19 through the mixed burner 18, and the rotary kiln 19 supplies raw materials to the ore-heating furnace 1.

[0038] The energy-saving system is described in detail below.

[0039] A water cooling pipe for rapid pre-cooling of the furnace gas is provided at the beginning of the furnace gas pipe 2.

[0040] After the furnace gas of the ore-fired furnace 1 leaves the furnace cover, due to the high temperature, a water-cooling sleeve is set before entering the purification area for rapid pre-cooling treatment, and then enters the furnace gas purification area after cooling. In the furnace gas pipeline 2, the first relief valve 3, the first air supply valve 4, and the first control unit 5 of the DCS distributed control system are arranged in sequence between the beginning of the furnace gas pipeline 2 and the input end of the cyclone 6. The first control unit 5 of the DCS distributed control system is used to monitor the temperature and pressure of the furnace gas. Once a fault occurs in the furnace gas purification equipment area or the parameters exceed the standard, the relief valve 3 can be automatically opened, so that the furnace gas automatically switches to the bypass direct exhaust chimney and ignites and burns.

[0041] The main function of the cyclone 6 is gas-solid separation, and the dust with a particle size greater than 5 μm is separated from the airflow by using the inertial force of the dust and the centrifugal force generated by the rotation of the dust-laden airflow.

[0042] Cooler 8 is a two-stage cooling device, so that the temperature of the furnace gas entering the dust collector can reach the specified requirement.

[0043] The rough air fan is arranged between the cooler 8 and the filter. The rough air fan adopts variable frequency control and is interlocked with the third control unit 10 of the DCS distributed control system on the furnace gas pipeline. When the furnace gas temperature in this section of the pipeline exceeds the set value, the rough air fan reduces the load and reduces the furnace gas volume. The rough air fan is a rough adjustment for temperature control, and the temperature adjustment in the purification area mainly depends on the cooler 8.

[0044] The first filter 11 and the second filter 12 are both bag-type dust collectors, which are used to filter dust with a particle size greater than 0.3 μm in the furnace gas. The dust removal efficiency can reach 99.5% to 99.99%, and the temperature control range is 80 to 260°C.

[0045] The clean air blower 14 is installed after the output end of the filter 12. The purified furnace gas is pressurized and transported to the furnace gas wind channel 21 of the mixed burner 18 by the clean air blower 14 to be burned as fuel together with the pulverized coal.

[0046] The DCS distributed control system is responsible for collecting real-time system information and issuing instructions, such as system parameters such as furnace pressure, furnace temperature, furnace gas composition, and issuing system cleaning instructions. Five groups of control units are set according to process requirements. The locations are as follows:

[0047] In the furnace gas pipeline 2, a second control unit 7 of the DCS distributed control system is provided between the gas output end of the cyclone 6 and the input end of the cooler 8. In the furnace gas pipeline 2, a rough blower 9 and a third control unit 10 of the DCS distributed control system are provided between the output end of the cooler 8 and the input end of the filter assembly. A clean air blower 14 for pressurizing the furnace gas is provided between the output end of the filter assembly and the end of the furnace gas pipeline 2, and a fourth control unit 13 of the DCS distributed control system is provided between the output end of the filter assembly and the clean air blower 14. A fifth control unit 15 of the DCS distributed control system, a second relief valve 16 and a second air supply valve 17 are provided in sequence between the output end of the clean air blower 14 and the end of the furnace gas pipeline 2.

[0048] The function of the first air supply valve 4 and the second air supply valve 17 is to adjust the air volume in the furnace gas pipeline 2 by adjusting the opening of the air supply valve to achieve the function of stabilizing the pressure in the furnace of the ore-fired furnace 1. At the same time, the system detects the contents of three gases, H2, O2 and CO in the furnace gas online, sends data to the centralized control center based on the furnace gas flow rate and the content of combustible components such as CO, adjusts the supply of furnace gas and pulverized coal fuel in real time, and optimizes the gas-solid fuel mixing ratio.

[0049] like Figure 2 As shown, the mixed burner 18 includes a pulverized coal air channel 20, a furnace gas air channel 21, a compressed air channel 22, a diesel channel 23, a central air channel 24, a first flange 25, a swirl air channel 26, a second flange 27, a third flange 28, an axial flow air channel 29, an air swirler 30, an outlet disc 31, a flame detector and an ignition burner, wherein the main body of the mixed burner 18 is a 6-layer concentrically arranged pipeline, the air swirler 30 and the outlet disc 31 are arranged at the outlet end of the main body of the mixed burner 18, and the main body of the mixed burner 18 Six layers of cavities are formed in the six layers of concentric pipes, the outermost cavity of the main body of the mixed burner 18 is connected to the axial flow air channel 29, the second outermost cavity of the mixed burner 18 is connected to the swirl air channel 26, the third outermost cavity of the mixed burner 18 is connected to the pulverized coal air channel 20, the fourth outermost cavity of the mixed burner 18 is connected to the end of the furnace gas pipeline 2, the fifth outermost cavity of the mixed burner 18 is connected to the central air channel 24, the innermost cavity of the mixed burner 18 is connected to the diesel channel 23, and the compressed air channel 22 is connected to the innermost cavity of the mixed burner 18;

[0050] The central air passage 24, the swirl air passage 26 and the axial air passage 29 all pass air, and are used to deliver combustion-supporting air to the mixed burner 18;

[0051] The pulverized coal air channel 20 is connected to the external pulverized coal pipeline and is used to transport pulverized coal particles into the mixed combustion nozzle 18;

[0052] The furnace gas air channel 21 is communicated with the end of the furnace gas pipeline 2 and is used for conveying purified furnace gas to the mixed burner 18 .

[0053] The mixed burner 18 is a new type of six-channel burner. The mixed burner 18 is connected to the furnace gas purification system. Among the five channels, the axial flow wind channel 29, the swirl wind channel 26, and the central wind channel 24 are connected to the air duct, the coal powder wind channel 20 is connected to the coal powder pipeline, and the furnace gas wind channel 21 is connected to the end of the furnace gas pipeline 2. The three airflows of the central wind, the swirl wind, and the axial flow wind are conducive to providing enough air for the fuel, strengthening the heat exchange and mass transfer between the fluids, and ensuring the stable combustion of the fuel. After the coal powder is sent out of the mixed burner 18, it is diffused by the swirl wind at a certain angle, which increases the contact area between the coal powder and the air, so that the coal powder burns in time. When the swirl intensity at the center of the jet increases to a certain value, a recirculation zone with a ring vortex shape will be established at the center of the jet, which is conducive to strengthening the intensity of the mixing of coal powder and high-temperature furnace gas, so that the coal powder quickly absorbs heat, and at the same time prolongs the residence time of the coal powder, making the coal powder ignition more stable. Adjusting the ratio of internal and external winds can change the swirl intensity.

[0054] In addition, the mixed burner 18 is also provided with a plurality of flanges, for example, Figure 2 The first flange 25, the second flange 27, the third flange 28, etc., multiple flanges can stably install the components of the mixed burner 18. The front end of the mixed burner 18 is provided with an outlet disc 31, and the front part of the outlet disc 31 is a combustion chamber.

[0055] In the first technical solution, the DCS distributed control system first control unit 5, the DCS distributed control system second control unit 7, the DCS distributed control system third control unit 10, and the DCS distributed control system fourth control unit 13 have the function of measuring gas pressure and temperature, and the DCS distributed control system fifth control unit 15 has the effect of measuring gas pressure, temperature, and measuring gas components.

[0056] This implementation case proposes an energy-saving method for recovering combustible components of furnace gas of a submerged arc furnace 1, using an energy-saving system for recovering combustible components of furnace gas of a submerged arc furnace 1 as in Example 1, including the following steps:

[0057] Step 1: After the furnace gas of the submerged arc furnace 1 leaves the furnace cover, it enters the water cooling pipe of the purification device for rapid pre-cooling treatment;

[0058] Step 2: The pre-cooled furnace gas enters the cyclone 6, and the dust with a particle size greater than 5 μm is separated from the airflow by the inertial force of the dust and the centrifugal force generated by the rotation of the dust-containing gas flow, thereby achieving gas-solid separation;

[0059] Step 3: The separated furnace gas enters the cooler 8 and the rough blower 9, so that the furnace gas can reach the temperature requirement of the subsequent filter to avoid unnecessary damage to subsequent equipment;

[0060] Step 4: The cooled furnace gas enters the filter assembly, and the dust with a particle size larger than 0.3 μm is filtered and collected one by one;

[0061] Step 5: The dust-removed furnace gas enters the clean gas blower 14 and is transported to the furnace gas air channel 21 of the mixed combustion nozzle 18 in the rotary kiln 19 after being pressurized, thereby completing the recovery and purification of the furnace gas of the ore-fired furnace 1.

[0062] Step 6: The DCS distributed control system sends data to the centralized control center based on the furnace gas flow rate and the content of combustible components such as CO, adjusts the supply of furnace gas and pulverized coal fuel in real time, and optimizes the gas-solid fuel mixing ratio.

[0063] As shown in Example 1 and Example 2, this method replaces part of the pulverized coal fuel with the recovered furnace gas, which can solve the pollution problem of the furnace gas of the ore-fired furnace 1 and the waste problem of waste heat and waste energy, and realize the resource utilization of the furnace gas. At the same time, it also reduces the consumption of non-renewable energy-coal, and relieves the pressure on the development of the coal-using industry. The mixed combustion nozzle 18 realizes the mixed combustion of pulverized coal and combustible gases such as CO in the rotary kiln 19. The burner sends air, combustible gas fuels such as CO and pulverized coal into the rotary kiln 19 in the order of central wind, combustible gas fuels such as CO, pulverized coal fuel, swirl wind and axial flow wind. The swirl wind increases the diffusion of pulverized coal particles, and the flammability of gas fuel increases the combustion rate of pulverized coal fuel. It not only helps to improve the full combustion of pulverized coal and the temperature distribution in the kiln, but also reduces the emission of harmful substances such as sulfides. Compared with pure pulverized coal, adding gas fuel makes it easier to control the flame, improves the stability of the flame, increases the range of the roasting zone, and improves the overall combustion efficiency. At the same time, it can also improve the problem of over-sintering or under-sintering caused by the combustion of pure pulverized coal.

[0064] The above contents are only preferred embodiments of the present invention. For ordinary technicians in this field, many changes can be made in the specific implementation methods and application scopes based on the ideas of the present technical content. As long as these changes do not deviate from the concept of the present invention, they all fall within the scope of protection of this patent.

Claims

1. An energy-saving system for recovering combustible components of furnace gas from an ore-fired furnace, characterized in that: The invention comprises a furnace gas pipeline, a cyclone, a cooler, a filter assembly and a mixed burner, wherein the starting end of the furnace gas pipeline is arranged inside the ore-fired furnace, the end of the furnace gas pipeline is connected to the mixed burner, the mixed burner is placed in the rotary kiln, and the cyclone, the cooler and the filter assembly are arranged in sequence between the starting end and the end of the furnace gas pipeline; The cyclone is used to separate dust with a particle size greater than 5 μm in the furnace gas; The cooler is used to cool the furnace gas; The filter assembly is used to filter dust with a particle size greater than 0.3 μm in the furnace gas; The furnace gas pipeline is used to recover the combustible gas in the ore-fired furnace and ignite it in the rotary kiln through the mixed combustion nozzle; In the furnace gas pipeline, a first relief valve, a first air supply valve and a first control unit of a DCS distributed control system are sequentially arranged between the starting end of the furnace gas pipeline and the input end of the cyclone; A clean air blower for pressurizing the furnace gas is provided between the output end of the filter assembly and the end of the furnace gas pipeline; A fifth control unit of a DCS distributed control system, a second relief valve and a second air supply valve are arranged in sequence between the output end of the clean air blower and the end of the furnace gas pipeline; The mixed burner comprises a pulverized coal air channel, a furnace gas air channel, a compressed air channel, a diesel channel, a central air channel, a first flange, a swirl air channel, a second flange, a third flange, an axial flow air channel, an air swirler and an outlet disc, wherein the main body of the mixed burner is a 6-layer concentrically arranged pipe, the air swirler is arranged at the outlet end of the main body of the mixed burner, and 6 layers of cavities are formed in the 6 layers of concentric pipes of the main body of the mixed burner, the outermost cavity of the main body of the mixed burner is connected to the axial flow air channel, the second outermost cavity of the mixed burner is connected to the swirl air channel, the third outermost cavity of the mixed burner is connected to the pulverized coal air channel, the fourth outermost cavity of the mixed burner is connected to the furnace gas air channel, the fifth outermost cavity of the mixed burner is connected to the central air channel, the innermost cavity of the mixed burner is connected to the diesel channel, and the compressed air channel is connected to the innermost cavity of the mixed burner; The central air channel, the swirl air channel and the axial air channel all have air passing therethrough for conveying combustion-supporting air to the mixed combustion nozzle; The pulverized coal air channel is connected to the pulverized coal pipeline and is used to transport pulverized coal particles into the mixed combustion nozzle; The furnace gas wind channel is communicated with the end of the furnace gas pipeline and is used for conveying purified furnace gas to the mixed combustion nozzle.

2. The energy-saving system for recovering combustible components of furnace gas from an ore-fired furnace according to claim 1 is characterized in that: A water cooling pipeline for rapid pre-cooling of the furnace gas is provided at the beginning of the furnace gas pipeline.

3. The energy-saving system for recovering combustible components of furnace gas from an ore-fired furnace according to claim 1 is characterized in that: In the furnace gas pipeline, a second control unit of a DCS distributed control system is arranged between the gas output end of the cyclone and the input end of the cooler.

4. The energy-saving system for recovering combustible components of furnace gas from an ore-fired furnace according to claim 1 is characterized in that: In the furnace gas pipeline, a rough blower and a third control unit of a DCS distributed control system are arranged between the output end of the cooler and the input end of the filter assembly.

5. The energy-saving system for recovering combustible components of furnace gas from a submerged arc furnace according to claim 1 is characterized in that: A fourth control unit of a DCS distributed control system is arranged between the output end of the filter assembly and the clean air blower.

6. An energy-saving method for recovering combustible components of furnace gas from an ore-fired furnace, using the energy-saving system for recovering combustible components of furnace gas from an ore-fired furnace as claimed in any one of claims 1 to 5, characterized in that: The steps include: Step 1: After the furnace gas from the submerged arc furnace leaves the furnace cover, it enters the water cooling pipe of the purification device for rapid pre-cooling treatment; Step 2: The pre-cooled furnace gas enters the cyclone, and the dust with a particle size larger than 5μm is separated from the airflow by the inertial force of the dust and the centrifugal force generated by the rotation of the dust-laden airflow, thus achieving gas-solid separation; Step 3: The separated furnace gas enters the cooler and rough fan, so that the furnace gas can reach the temperature requirements of the subsequent filter to avoid unnecessary damage to subsequent equipment; Step 4: The cooled furnace gas enters the filter assembly, and the dust with a particle size larger than 0.3 μm is filtered and collected one by one; Step 5: The dust-removed furnace gas enters the clean gas blower and is transported to the furnace gas air channel of the mixed combustion nozzle in the rotary kiln after being pressurized, completing the recovery and purification of the furnace gas of the submerged arc furnace; Step 6: The DCS distributed control system sends data to the centralized control center based on the furnace gas flow rate and CO combustible component content, adjusts the supply of furnace gas and pulverized coal fuel in real time, and optimizes the gas-solid fuel mixing ratio.

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