An enclosed ore smelting furnace off gas treatment system

Abstract

The application discloses a closed furnace gas treatment system of a submerged arc furnace, which comprises a pneumatic conveying device, a primary cooling heat exchanger, a secondary cooling heat exchanger, a coke powder storage tank and a nitrogen storage tank. The primary cooling heat exchanger is arranged at the output side of a furnace gas output pipeline of the submerged arc furnace. The heat medium inlet of the secondary cooling heat exchanger is connected with the heat medium outlet of the primary cooling heat exchanger. The cold medium inlet of the secondary cooling heat exchanger is connected with the outlet end of the nitrogen storage tank. The cold medium outlet of the secondary cooling heat exchanger is connected with the gas inlet end of the pneumatic conveying device. The high-temperature flue gas before purification is subjected to heat exchange with nitrogen used for conveying coke powder. The temperature of the nitrogen containing coke powder can be increased, the influence on the internal temperature of the furnace gas output pipeline is reduced, the heat exchange equipment at the output side of the furnace gas output pipeline can assist in cooling the flue gas, the energy consumption for providing the cooling medium to the heat exchange equipment is reduced, and the furnace gas treatment cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of ore smelting equipment technology, and in particular to a closed-loop submerged arc furnace gas treatment system. Background Technology

[0002] Taking manganese silicon smelting as an example, the main gas volume composition of the flue gas produced during the production process is CO accounting for 55% to 75%, CO2 accounting for 5% to 20%, H2 accounting for 5% to 7%, N2 accounting for 13% to 16%, and O2 accounting for 0.5% to 1.5%. As can be seen from the above data, carbon dioxide and oxygen still account for a large proportion of the flue gas produced by existing closed-type electric arc furnaces. How to improve the calorific value of the gas from electric arc furnaces and obtain gas with higher utilization value is a problem faced in the production process of electric arc furnaces.

[0003] Those skilled in the art have proposed that coke powder can be injected into the flue gas output pipe of a closed-loop submerged arc furnace. Utilizing the high temperature of the flue gas (800-1100°C) in the water-cooled flue, the coke powder and flue gas can fully contact and react, thereby reducing the CO2 and O2 content in the flue gas. In this method, compressed nitrogen is used for coke powder injection. However, this approach has a technical problem: due to the significant temperature difference between the nitrogen carrying the coke powder and the internal temperature of the flue gas output pipe, a large influx of nitrogen into the pipe lowers the internal temperature. Since the reaction between the coke powder and the flue gas requires a temperature of 800-1100°C, this temperature difference affects the reaction, resulting in a less than ideal effect and thus lower CO2 and O2 content. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a closed-loop furnace gas treatment system for submerged arc furnaces. To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended as a general description, nor is it intended to identify key / important components or to describe the scope of protection of these embodiments. Its sole purpose is to present some concepts in a simple form as a prelude to the detailed description that follows.

[0005] The present invention adopts the following technical solution:

[0006] This invention provides a closed-loop submerged arc furnace gas treatment system, comprising: a pneumatic conveying device, a primary cooling heat exchanger, a secondary cooling heat exchanger, a coke powder storage tank, and a nitrogen storage tank;

[0007] The primary cooling heat exchanger is located on the output side of the furnace gas output pipeline of the submerged arc furnace. The heat medium inlet of the secondary cooling heat exchanger is connected to the heat medium outlet of the primary cooling heat exchanger. The refrigerant inlet of the secondary cooling heat exchanger is connected to the outlet end of the nitrogen storage tank. The refrigerant outlet of the secondary cooling heat exchanger is connected to the gas inlet end of the pneumatic conveying device.

[0008] The coke powder storage tank is connected to the feed inlet of the pneumatic conveying device.

[0009] Furthermore, the aforementioned closed-loop submerged arc furnace gas treatment system further includes: a drying gas duct and a nitrogen conveying fan; the outlet of the nitrogen conveying fan is connected to the refrigerant inlet of the primary cooling heat exchanger, the refrigerant outlet of the primary cooling heat exchanger is connected to the drying gas duct, and the drying gas duct is connected to the coke powder storage tank.

[0010] Furthermore, the aforementioned closed-loop submerged arc furnace gas treatment system further includes: a cyclone separator, a heat exchange device, and a material mixer; the inlet end of the cyclone separator is connected to the output side of the submerged arc furnace gas output pipeline, the material mixer is connected to the dust outlet of the cyclone separator, the heat medium inlet of the heat exchange device is connected to the gas outlet of the cyclone separator, and the heat medium outlet of the heat exchange device is connected to the heat medium inlet of the primary cooling heat exchanger.

[0011] Furthermore, the aforementioned closed-loop submerged arc furnace gas treatment system further includes: a uniform mixing device; the uniform mixing device is connected to the outlet of the pneumatic conveying device, and the uniform mixing device is disposed in the horizontal flue of the submerged arc furnace gas output pipeline.

[0012] Furthermore, the material mixer includes: a dust collection tank, a Venturi conveyor, and a supply pipe; the inlet of the dust collection tank is connected to the dust outlet of the cyclone separator, and the drying air inlet of the dust collection tank is connected to the drying air duct; the material supply port of the dust collection tank is connected to the inlet of the Venturi conveyor, one end of the supply pipe is connected to the outlet of the Venturi conveyor, and the other end of the supply pipe is located on the pipeline connecting the pneumatic conveying device and the uniform mixing device.

[0013] Furthermore, the closed-loop submerged arc furnace gas treatment system further includes: a gas purification device and a gas storage tank, wherein the heat medium outlet of the secondary cooling heat exchanger is connected to the gas inlet of the gas purification device, and the gas outlet of the gas purification device is connected to the inlet end of the gas storage tank.

[0014] Furthermore, the closed-loop submerged arc furnace gas treatment system further includes: a first recovery storage tank and a second recovery storage tank, wherein the first recovery storage tank is connected to the dust collection tank and the second recovery storage tank is connected to the coke powder storage tank.

[0015] The beneficial effects of this invention are as follows: This application exchanges heat between the high-temperature flue gas before purification and the nitrogen gas used to transport coke powder. This not only increases the temperature of the coke powder-containing nitrogen gas and reduces the impact on the internal temperature of the furnace gas output pipeline, but also assists the heat exchange equipment located on the output side of the furnace gas output pipeline in cooling the flue gas, thereby reducing the energy consumption for providing cooling medium to the heat exchange equipment and reducing the cost of furnace gas treatment. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of a closed-loop submerged arc furnace gas treatment system according to the present invention. Detailed Implementation

[0018] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be understood that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0019] like Figure 1 As shown in some illustrative embodiments, the present invention provides a closed-loop submerged arc furnace gas treatment system, which is installed on the output side of the closed-loop submerged arc furnace 1. This system is used to treat and recover the flue gas discharged from the closed-loop submerged arc furnace 1 to obtain gas with a higher calorific value compared to existing submerged arc furnaces. Here, the output side refers to the side from which the flue gas is output. The gas treatment system in this embodiment includes: a cyclone separator 2, a pneumatic conveying device 302, a nitrogen storage tank 301, a coke powder storage tank 4, a uniform mixing device 5, a material mixer 6, a heat exchanger 7, a gas purification device 8, a gas storage tank 9, a primary cooling heat exchanger 10, a secondary cooling heat exchanger 11, a drying air duct 12, and a nitrogen conveying fan 13.

[0020] Nitrogen storage tank 301 provides compressed nitrogen to pneumatic conveying device 302. The compressed nitrogen carries the coke powder released from coke powder storage tank 4 and is conveyed together to the furnace gas output pipeline of the closed-loop submerged arc furnace 1. The material supply port of coke powder storage tank 4 is connected to the feed port of pneumatic conveying device 302, and the uniform mixing device 5 is connected to the discharge port of pneumatic conveying device 302. The uniform mixing device 5 is located in the furnace gas output pipeline of the closed-loop submerged arc furnace 1, specifically in the horizontal flue 101 of the furnace gas output pipeline and before the water-cooled flue 102.

[0021] The nitrogen storage tank 301 stores compressed nitrogen, and the gas outlet of the gas purification device 8 is connected to the nitrogen storage tank 301 and the nitrogen conveying fan 13. A compressor is installed on the conveying pipeline so that the nitrogen in a portion of the purified furnace gas is compressed and conveyed to the nitrogen storage tank 301 and supplied to the nitrogen conveying fan 13. In other words, the material is conveyed by using compressed nitrogen and the nitrogen in a portion of the purified furnace gas, which can reduce the input cost of nitrogen.

[0022] The uniform mixing device 5 is installed inside the horizontal flue 101 to discharge nitrogen mixed with coke powder into the horizontal flue 101, so that the coke powder can be fully mixed with the flue gas. In this embodiment, the uniform mixing device 5 is used to discharge nitrogen mixed with coke powder into the horizontal flue 101, so that the coke powder can be fully mixed with the flue gas, and any existing device capable of gas-to-gas mixing can be used.

[0023] The inlet of cyclone separator 2 is connected to the output side of water-cooled flue 102, where the output side refers to the side where flue gas is output. Material mixer 6 is installed on the pipeline connecting pneumatic conveying device 302 and uniform mixing device 5, and is also connected to the dust outlet of cyclone separator 2. A cyclone dust collector 2 is added after water-cooled flue 102 for the collection and recycling of coke-containing dust. The flue gas discharged from water-cooled flue 102 enters the cyclone dust collector 2 for gas-solid separation. High-temperature coal gas is discharged through the gas outlet of cyclone separator 2, and coke-containing dust is discharged through the dust outlet of cyclone separator 2. Material mixer 6 mixes the coke-containing dust with nitrogen gas mixed with coke powder output from pneumatic conveying device 302, and then sends both mixtures into uniform mixing device 5, achieving the recycling of coke-containing dust and avoiding resource waste.

[0024] The heat exchanger 7's heat medium inlet is connected to the gas outlet of the cyclone separator 2. Since the flue gas discharged from the cyclone separator 2 has a high temperature, the heat exchanger 7 is needed to cool this portion of the flue gas to a suitable temperature before it can enter the gas purification device 8 for subsequent treatment and purification steps. This heat exchange and cooling process requires a large amount of cooling medium to be supplied to the heat exchanger 7, resulting in significant energy consumption. Therefore, in this embodiment, a primary cooling heat exchanger 10 and a secondary cooling heat exchanger 11 are sequentially installed on the output side of the heat exchanger 7 to assist the heat exchanger 7 in cooling the flue gas, thereby reducing the energy consumption for supplying the cooling medium to the heat exchanger 7 and lowering the cost of furnace gas treatment.

[0025] The primary cooling heat exchanger 10 is located on the output side of the furnace gas output pipe of the closed-loop submerged arc furnace 1, specifically on the output side of the heat exchange device 7. The heat medium outlet of the heat exchange device 7 is connected to the heat medium inlet of the primary cooling heat exchanger 10. The heat medium inlet of the secondary cooling heat exchanger 11 is connected to the heat medium outlet of the primary cooling heat exchanger 10. The refrigerant inlet of the secondary cooling heat exchanger 11 is connected to the outlet end of the nitrogen storage tank 301, and the refrigerant outlet of the secondary cooling heat exchanger 11 is connected to the air inlet end of the pneumatic conveying device 302. The pneumatic conveying device 302 operates on the principle of using the kinetic energy of the airflow to suspend the particulate material and transport it along the pipeline with the airflow.

[0026] After being cooled by heat exchanger 7, the flue gas enters primary cooling heat exchanger 10 for a second cooling, and then enters secondary cooling heat exchanger 11 for a third cooling. The cooling medium used in secondary cooling heat exchanger 11 is compressed nitrogen from nitrogen storage tank 301. This structural design not only cools the flue gas but also increases the temperature of the nitrogen supplied by the pneumatic conveying device. This reduces energy consumption while increasing the temperature of the nitrogen containing coke powder, thereby reducing the impact on the internal temperature of the furnace gas output pipeline. It ensures sufficient reaction between the coke powder and the flue gas, allowing the carbon in the coke powder to oxidize with O2 in the flue gas to produce CO, and the coke powder to reduce CO2 in the flue gas to produce CO, effectively reducing the CO2 and O2 content in the coal gas.

[0027] The outlet of the nitrogen conveying fan 13 is connected to the refrigerant inlet of the primary cooling heat exchanger 10, and the refrigerant outlet of the primary cooling heat exchanger 10 is connected to the drying air duct 12. The drying air duct 12 is connected to the coke powder storage tank 4 and the material mixer 6. The nitrogen conveying fan 13 conveys nitrogen generated from other processes to the refrigerant inlet of the primary cooling heat exchanger 10. The cooling medium used by the primary cooling heat exchanger 10 for cooling is nitrogen supplied by the nitrogen conveying fan 13. After the nitrogen supplied by the nitrogen conveying fan 13 is heated by heat exchange in the primary cooling heat exchanger 10, it is conveyed to the coke powder storage tank 4 and the material mixer 6 to perform high-temperature drying of the coke powder in the coke powder storage tank 4 and the coke powder-containing dust in the material mixer 6. This can further increase the temperature of the coke powder-containing nitrogen conveyed to the horizontal flue 101, and remove most of the moisture in the coke powder and coke powder-containing dust, ensuring the dispersion of the powder and preventing it from agglomerating into larger particles that would affect the conveying process and the reaction between the coke powder and the flue gas.

[0028] The heat medium outlet of the secondary cooling heat exchanger 11 is connected to the gas inlet of the gas purification device 8, and the gas outlet of the gas purification device 8 is connected to the inlet of the gas storage tank 9. The gas discharged from the cyclone separator 2 first enters the heat exchanger 7, the primary cooling heat exchanger 10, and the secondary cooling heat exchanger 11 for three heat exchange and cooling processes. Then, the low-temperature gas is transported to the gas purification device 8 for purification. The gas purification device 8 can be any existing gas purification equipment. The purified gas is pressurized and transported to the gas storage tank 9 for pressure stabilization and buffering, ultimately yielding gas that can be directly used by the user.

[0029] The material mixer 6 includes: a dust collection tank 601, a venturi conveyor 602, and a supply pipe 603.

[0030] The inlet of the dust collection tank 601 is connected to the outlet of the cyclone separator 2, and the dry air inlet of the dust collection tank 601 is connected to the drying air duct 12. The material supply port of the dust collection tank 601 is connected to the inlet of the Venturi conveyor 602. The dust containing coke powder discharged from the cyclone separator 2 enters the dust collection tank 601 and is then supplied to the supply pipe 603. One end of the supply pipe 603 is connected to the outlet of the Venturi conveyor 602, and the other end of the supply pipe 603 is located on the pipeline connecting the pneumatic conveying device 302 and the uniform mixing device 5. The Venturi conveyor 602 blows the dust containing coke powder into the pipeline connecting the pneumatic conveying device and the uniform mixing device 5 through the supply pipe 603, where it mixes with the nitrogen gas containing coke powder output from the pneumatic conveying device, and then sends them together into the uniform mixing device 5.

[0031] The furnace gas treatment system in this embodiment further includes a first recovery storage tank 14 and a second recovery storage tank 15. The first recovery storage tank 14 is connected to the dust collection tank 601, and the second recovery storage tank 15 is connected to the coke powder storage tank 4. Nitrogen gas after drying the material can be discharged into the first recovery storage tank 14 and the second recovery storage tank 15 to collect the material carried out by the nitrogen gas during the material drying operation.

[0032] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A closed-loop furnace gas treatment system for a submerged arc furnace, characterized in that, include: Pneumatic conveying device, primary cooling heat exchanger, secondary cooling heat exchanger, coke powder storage tank, nitrogen storage tank, drying air duct and nitrogen conveying fan; The primary cooling heat exchanger is located on the output side of the furnace gas output pipeline of the submerged arc furnace. The heat medium inlet of the secondary cooling heat exchanger is connected to the heat medium outlet of the primary cooling heat exchanger. The refrigerant inlet of the secondary cooling heat exchanger is connected to the outlet end of the nitrogen storage tank. The refrigerant outlet of the secondary cooling heat exchanger is connected to the air inlet end of the pneumatic conveying device. The pneumatic conveying device uses the kinetic energy of the airflow to make the granular material suspended and conveyed along the pipeline with the airflow. The coke powder storage tank is connected to the inlet of the pneumatic conveying device; The outlet of the nitrogen conveying fan is connected to the refrigerant inlet of the primary cooling heat exchanger, the refrigerant outlet of the primary cooling heat exchanger is connected to the drying air duct, and the drying air duct is connected to the coke powder storage tank. After being cooled by the heat exchange equipment, the flue gas enters the primary cooling heat exchanger for a second cooling, and then enters the secondary cooling heat exchanger for a third cooling. The cooling medium used in the secondary cooling heat exchanger is compressed nitrogen from a nitrogen storage tank.

2. The closed-loop submerged arc furnace gas treatment system according to claim 1, characterized in that, Also includes: The system includes a cyclone separator, a heat exchanger, and a material mixer. The inlet of the cyclone separator is connected to the output side of the furnace gas output pipeline of the submerged arc furnace. The material mixer is connected to the dust outlet of the cyclone separator. The heat medium inlet of the heat exchanger is connected to the gas outlet of the cyclone separator. The heat medium outlet of the heat exchanger is connected to the heat medium inlet of the primary cooling heat exchanger.

3. The closed-loop submerged arc furnace gas treatment system according to claim 2, characterized in that, Also includes: A uniformly distributed mixing device; the uniformly distributed mixing device is connected to the outlet of the pneumatic conveying device, and the uniformly distributed mixing device is installed in the horizontal flue of the furnace gas output pipeline of the submerged arc furnace.

4. The closed-loop submerged arc furnace gas treatment system according to claim 3, characterized in that, The material mixer includes: a dust collection tank, a Venturi conveyor, and a supply pipeline; The inlet of the dust collection tank is connected to the dust outlet of the cyclone separator, and the dry air inlet of the dust collection tank is connected to the drying air duct. The material supply port of the dust collection tank is connected to the inlet of the Venturi conveyor, one end of the supply pipe is connected to the outlet of the Venturi conveyor, and the other end of the supply pipe is located on the pipeline connecting the pneumatic conveying device and the uniform mixing device.

5. A closed-loop submerged arc furnace gas treatment system according to claim 4, characterized in that, Also includes: The gas purification device and the gas storage tank are provided, wherein the heat medium outlet of the secondary cooling heat exchanger is connected to the gas inlet of the gas purification device, and the gas outlet of the gas purification device is connected to the inlet end of the gas storage tank.

6. A closed-loop submerged arc furnace gas treatment system according to claim 5, characterized in that, Also includes: A first recovery storage tank and a second recovery storage tank, wherein the first recovery storage tank is connected to the dust collection tank and the second recovery storage tank is connected to the coke powder storage tank.

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