Efficient treatment device for multiple pollutants in lepidolite and spodumene roasting flue gas

Abstract

The utility model discloses a lepidolite spodumene roasting flue gas multi-pollutant efficient treatment device which comprises a high-temperature dust removal and denitration integrated tower, a fan, a flue gas deacidification tower and a flue gas heat exchanger, the high-temperature dust removal and denitration integrated tower is communicated with a kiln tail of a roasting kiln, and a cooling section of the flue gas heat exchanger is communicated with the high-temperature dust removal and denitration integrated tower and the fan. Flue gas is subjected to heat exchange in the cooling section and then conveyed to the flue gas deacidification tower through a fan, a gas outlet of the flue gas deacidification tower is communicated with the heating section of the flue gas heat exchanger, the flue gas is subjected to heat exchange with flue gas of the high-temperature dust removal and denitration integrated tower in the flue gas heat exchanger to be heated, and the flue gas is discharged through a chimney communicated with the heating section on the flue gas heat exchanger. The device disclosed by the utility model can be used for cooperatively treating various pollutants including dust, SO2, HF, HCL, nitrogen oxides, dioxin, heavy metals and the like, so that high-efficiency treatment on flue gas is realized, and good economic benefits are achieved.

Description

Technical Field

[0001] This utility model relates to the field of flue gas treatment technology, specifically to a high-efficiency treatment device for multiple pollutants in flue gas from calcination of lepidolite and spodumene. Background Technology

[0002] In recent years, with the strong rise and development of the new energy power industry, the demand for lithium batteries is expanding rapidly. Lithium smelting projects are playing an increasingly important role in the new energy industry. Lithium smelting mainly uses lepidolite and spodumene as raw materials, and adopts rotary kiln pyrometallurgical smelting. The resulting flue gas contains a large amount of pollutants such as heavy metal dust, SO2, and nitrogen oxides, which seriously pollute the environment.

[0003] With the ultra-low emission transformation of various industries, a variety of flue gas treatment processes have emerged, providing positive solutions for air pollution control. However, lepidolite / spodumene roasting flue gas is characterized by high pollutant concentrations, complex composition, and mutual coupling, as well as high flue gas temperature and large fluctuations. Simply relying on one or a combination of processes cannot solve the problem of achieving emission standards for various pollutants in the flue gas. Therefore, the development of new high-efficiency roasting flue gas treatment devices or methods has been put on the agenda. Utility Model Content

[0004] Technical objective: To address the shortcomings of existing lepidolite / spodumene roasting flue gas treatment methods, this utility model discloses a high-efficiency multi-pollutant treatment device for lepidolite / spodumene roasting flue gas.

[0005] Technical solution: To achieve the above technical objectives, the present invention adopts the following technical solution:

[0006] A high-efficiency multi-pollutant treatment device for spodumene roasting flue gas includes a high-temperature dust removal and denitrification integrated tower, a fan, a flue gas desulfurization tower, and a flue gas heat exchanger. The high-temperature dust removal and denitrification integrated tower is connected to the kiln tail of the roasting kiln. The cooling section of the flue gas heat exchanger is connected to the high-temperature dust removal and denitrification integrated tower and the fan. After heat exchange in the cooling section, the flue gas is transported to the flue gas desulfurization tower by the fan. The gas outlet of the flue gas desulfurization tower is connected to the heating section of the flue gas heat exchanger. The gas exchanges heat with the flue gas in the high-temperature dust removal and denitrification integrated tower and is heated. The gas is then discharged through a chimney connected to the heating section of the flue gas heat exchanger.

[0007] Preferably, the high-temperature dust removal and denitrification integrated tower of this invention is arranged with filter tubes, denitrification catalyst and soot blower in sequence along the flue gas flow direction. An ammonia water spray gun with the spray direction consistent with the flue gas flow direction is set at the center of the kiln tail. After the ammonia water is vaporized in the high-temperature environment at the kiln tail, it enters the high-temperature dust removal and denitrification integrated tower with the flue gas and is denitrified under the catalysis of the denitrification catalyst.

[0008] Preferably, the ammonia spray gun of this invention is a dual-fluid spray gun with an average droplet diameter of less than 50 μm.

[0009] Preferably, the filter tube of this utility model is a ceramic fiber filter tube, which is resistant to temperature of 250-400℃.

[0010] Preferably, the denitrification catalyst of this invention is a honeycomb-type medium-high temperature catalyst with a catalyst window temperature of 320°C.

[0011] Preferably, the soot blower of this utility model is a rake-type soot blower, and the soot blowing medium is saturated steam with a steam pressure greater than 1.2 MPa.

[0012] Preferably, the flue gas deacidification tower of this invention is equipped with a slurry spray gun, through which alkaline slurry is sprayed to perform flue gas deacidification treatment.

[0013] Beneficial Effects: The multi-pollutant high-efficiency treatment device for lepidolite roasting flue gas disclosed in this utility model has the following beneficial effects:

[0014] 1. This utility model can recover beneficial components from furnace flue gas, realizing the resource utilization of waste such as dust.

[0015] 2. This utility model can synergistically treat multiple pollutants, including dust, SO2, HF, HCl, nitrogen oxides, dioxins, heavy metals, etc., achieving good economic benefits.

[0016] 3. This utility model occupies a small area, has low investment and operating costs, and is easy to operate and maintain, making it suitable for large-scale promotion.

[0017] 4. This utility model can treat flue gas with high pollutant concentrations, with particulate matter concentration <30g / Nm3, SO2 concentration <8000mg / Nm3, and nitrogen oxide concentration <800mg / Nm3. The flue gas at the chimney outlet can stably meet the ultra-low emission standards.

[0018] 5. This utility model reduces energy consumption and improves pollutant removal efficiency by using a flue gas heat exchanger. Furthermore, the end-stage heating of the flue gas transforms it into unsaturated flue gas, increasing its diffusion rate in the atmosphere and eliminating the white smoke phenomenon observed in traditional wet desulfurization towers, thus improving the visual quality. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0020] Figure 1 This is a schematic diagram of the overall structure of the processing device of this utility model;

[0021] Among them, 1-high temperature dust removal and denitrification integrated tower, 2-fan, 3-flue gas deacidification tower, 4-flue gas heat exchanger, 5-calcining kiln, 6-chimney, 7-filter tube, 8-denitrification catalyst, 9-soot blower, 10-ammonia water spray gun, 11-slurry spray gun. Detailed Implementation

[0022] Reference will now be made in detail to embodiments of the present disclosure, one or more of which are set forth herein. Each embodiment and example is provided by way of explanation of the apparatus, composition, and materials of the present disclosure, and not by way of limitation. Rather, the following description provides convenient illustrations for implementing exemplary embodiments of the present disclosure. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made to the teachings of the present disclosure without departing from the scope or spirit of the present disclosure.

[0023] like Figure 1 As shown, this utility model discloses a high-efficiency treatment device for multiple pollutants in spodumene roasting flue gas, including a high-temperature dust removal and denitrification integrated tower 1, a fan 2, a flue gas desulfurization tower 3, and a flue gas heat exchanger 4. The high-temperature dust removal and denitrification integrated tower 1 is connected to the kiln tail of the roasting kiln 5. The cooling section of the flue gas heat exchanger 4 is connected to the high-temperature dust removal and denitrification integrated tower 1 and the fan 2. After heat exchange in the cooling section, the flue gas is transported to the flue gas desulfurization tower 3 by the fan 1. The gas outlet of the flue gas desulfurization tower 3 is connected to the heating section of the flue gas heat exchanger 4. The flue gas exchanges heat with the flue gas in the high-temperature dust removal and denitrification integrated tower 1 in the flue gas heat exchanger 4 and is heated. The gas is then discharged through a chimney 6 connected to the heating section of the flue gas heat exchanger 4.

[0024] This utility model's flue gas heat exchanger 4 adopts a plate heat exchanger made of SUS316L stainless steel to meet the heat exchange requirements of high-temperature flue gas. The high-temperature dust removal and denitrification integrated tower 1 of this utility model adopts a bottom-in, top-out configuration. Inside the tower, along the flow direction of the flue gas, filter tubes 7, denitrification catalyst 8, and soot blower 9 are sequentially arranged. The tower body is made of heat-resistant stainless steel SUS-321, and the filter tubes 7 are ceramic fiber filter tubes with a temperature resistance of 250-400℃, selected according to the temperature of the flue gas being treated. Gas-solid separation is performed on the flue gas entering the tower through the filter tubes 7. Spodumene dust falls to the bottom of the tower, is collected, and then discharged. The denitrification catalyst 8 is layered according to the nitrogen oxide concentration at the flue gas inlet and the denitrification efficiency. The gas parameters at the flue gas outlet of the roasting kiln are collected in advance for setting. The denitrification catalyst 8 adopts a honeycomb-type medium-high temperature catalyst to ensure that it can fully react with the flue gas. An ammonia water spray gun 10 with the spray direction consistent with the flue gas flow direction is set at the center of the kiln tail of the roasting kiln 5. After the ammonia water vaporizes in the high temperature environment at the kiln tail, it enters the high temperature dust removal and denitrification integrated tower 1 with the flue gas. Under the catalysis of the denitrification catalyst, the flue gas denitrification treatment is carried out. In order to ensure that the ammonia water can be completely vaporized and fully mixed with the flue gas, and to improve the subsequent flue gas denitrification treatment effect, the ammonia water spray gun 10 of this utility model is a dual-fluid spray gun with an average droplet particle size of less than 50um. The soot blower 9 is a rake-type soot blower, and the soot blowing medium is saturated steam with a steam pressure greater than 1.2Mpa, preferably 1.6Mpa.

[0025] The flue gas after denitrification treatment enters the flue gas deacidification tower 3 for deacidification treatment to remove acidic gases such as SO2 from the flue gas. The flue gas deacidification tower 3 of this invention adopts a bottom-in, top-out form. The inside of the deacidification tower is lined with an anti-corrosion coating, or the whole is made of corrosion-resistant materials. A slurry spray gun 11 is set in the flue gas deacidification tower. An alkaline slurry is sprayed through the slurry spray gun 11 to carry out flue gas deacidification treatment. The alkaline slurry is preferably Ca(OH)2 slurry. The number of spray gun layers and the number of spray guns per layer are set according to the SO2 concentration at the inlet / outlet of the deacidification tower.

[0026] The present invention will be described below through a specific embodiment, which treats the flue gas from a spodumene roasting kiln of a new materials company. The inlet flue gas flow rate of the device is approximately 68,000 Nm³ / h (standard dry flue gas), the flue gas temperature is 260-320℃, and the inlet SO₂ concentration is 2500-3200 mg / Nm³. 3 The particulate matter concentration was 5000 mg / Nm³. 3 The inlet nitrogen oxide concentration is 300-420 mg / Nm³. 3 The filter tube 7 of this invention is heat-resistant up to 400℃, the denitrification catalyst 5 has a window temperature of 320℃, the soot blower 4 uses saturated steam as the soot blowing medium, and the steam pressure is 1.6MPa. The flue gas desulfurization tower is equipped with two layers of spray guns, with four spray guns in each layer. The medium of the spray guns is Ca(OH)2 slurry.

[0027] When the high-temperature flue gas from spodumene roasting passes through the tail end of the furnace, ammonia water droplets are sprayed into the flue gas by ammonia water spray gun 10. After the droplets vaporize, they form a mixture of ammonia and flue gas, which enters the high-temperature dust removal and denitrification integrated tower 1. The flue gas first undergoes gas-solid separation through the filter pipe 7, and the spodumene dust falls to the bottom of the tower, is collected, and discharged externally. The flue gas after dust removal flows upward and undergoes an oxidation-reduction reaction with ammonia when it passes through the catalyst layer where the denitrification catalyst 8 is located, thus completing the removal of nitrogen oxides. Then, the flue gas is cooled down through the cooling section of the flue gas heat exchanger 4 and enters the flue gas deacidification tower 3. The alkaline solution sprayed into the flue gas deacidification tower 3 by the slurry spray gun is fully mixed and turbulent with the flue gas, efficiently removing acid washing gases such as SO2 from the flue gas. The flue gas is further cooled to form saturated flue gas. Finally, the clean flue gas is heated up through the heating section of the flue gas heat exchanger to form unsaturated flue gas, which is discharged into the atmosphere, eliminating the phenomenon of white smoke from the chimney.

[0028] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model 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 this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.

Claims

1. A high-efficiency treatment device for multiple pollutants in spodumene roasting flue gas, characterized in that, The system includes a high-temperature dust removal and denitrification integrated tower (1), a fan (2), a flue gas desulfurization tower (3), and a flue gas heat exchanger (4). The high-temperature dust removal and denitrification integrated tower (1) is connected to the kiln tail of the roasting kiln (5). The cooling section of the flue gas heat exchanger (4) is connected to the high-temperature dust removal and denitrification integrated tower (1) and the fan (2). After the flue gas undergoes heat exchange in the cooling section, it is transported to the flue gas desulfurization tower (3) by the fan (2). The gas outlet of the flue gas desulfurization tower (3) is connected to the heating section of the flue gas heat exchanger (4). The flue gas heats up by exchanging heat with the flue gas in the high-temperature dust removal and denitrification integrated tower (1) in the flue gas heat exchanger (4) and is discharged through the chimney (6) connected to the heating section on the flue gas heat exchanger (4).

2. The high-efficiency treatment device for multiple pollutants in lepidolite roasting flue gas according to claim 1, characterized in that, The high-temperature dust removal and denitrification integrated tower (1) is equipped with a filter tube (7), a denitrification catalyst (8) and a soot blower (9) in sequence along the flue gas flow direction. An ammonia water spray gun (10) with the spray direction consistent with the flue gas flow direction is set at the center of the kiln tail of the calcining kiln (5). After the ammonia water is vaporized in the high-temperature environment at the kiln tail, it enters the high-temperature dust removal and denitrification integrated tower (1) with the flue gas and is denitrified under the catalysis of the denitrification catalyst.

3. The high-efficiency multi-pollutant treatment device for lepidolite roasting flue gas according to claim 2, characterized in that, The ammonia spray gun (10) is a dual-fluid spray gun with an average droplet diameter of less than 50 μm.

4. The high-efficiency treatment device for multiple pollutants in lepidolite roasting flue gas according to claim 2, characterized in that, The filter tube (7) is a ceramic fiber filter tube with a temperature resistance of 250-400℃.

5. The high-efficiency treatment device for multiple pollutants in lepidolite roasting flue gas according to claim 2, characterized in that, The denitrification catalyst (8) is a honeycomb-type medium-high temperature catalyst with a catalyst window temperature of 320°C.

6. The high-efficiency multi-pollutant treatment device for lepidolite roasting flue gas according to claim 2, characterized in that, The soot blower (9) is a rake-type soot blower, and the soot blowing medium is saturated steam with a steam pressure greater than 1.2 MPa.

7. The high-efficiency multi-pollutant treatment device for lepidolite roasting flue gas according to claim 1, characterized in that, The flue gas deacidification tower (3) is equipped with a slurry spray gun (11) to spray alkaline slurry for flue gas deacidification treatment.

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