System and method for denitration of high-sulfur flue gas in non-ferrous smelting

Abstract

The application provides a non-ferrous metal smelting high-sulfur flue gas denitration system and method, and belongs to the field of industrial waste gas treatment. The application provides a non-ferrous metal smelting high-sulfur flue gas denitration system, which comprises a heat exchanger 102, a heat exchanger 105 and a heat exchanger 107; an electric precipitator 104 connected with a first outlet of the heat exchanger 102; the electric precipitator 104 is connected with a first inlet of the heat exchanger 105; a first outlet of the heat exchanger 105 is connected with a second inlet of the heat exchanger 102; a denitration reactor 106 connected with a second outlet of the heat exchanger 102; the denitration reactor 106 is connected with a second inlet of the heat exchanger 105; a second outlet of the heat exchanger 105 is connected with a first inlet of the heat exchanger 107; and a dynamic wave scrubber 108 connected with a first outlet of the heat exchanger 107.

Description

Technical Field

[0001] This invention relates to the field of industrial waste gas treatment, specifically to a system and method for denitrifying high-sulfur flue gas from non-ferrous metal smelting. Background Technology

[0002] Non-ferrous metal smelting has developed rapidly as an important foundation supporting modern industry and technological development. With increasingly stringent global environmental protection requirements, the non-ferrous metal smelting industry faces the dual challenge of effectively reducing harmful gas emissions, improving production efficiency, and lowering carbon emissions.

[0003] The smelting process of ores rich in sulfur leads to the generation of high levels of SO2, typically ranging from 3% to 12%, making sulfur removal a major concern. Common flue gas sulfuric acid production technologies for smelting not only treat SO2 but also achieve the resource utilization of sulfur, while NO... x It was not properly treated and was directly emitted with the exhaust gas. NO in the flue gas x On the one hand, it will be converted into nitric acid (HNO3) as a byproduct during the acid production process, reducing the purity of the product sulfuric acid and decreasing economic benefits; NO x When it interacts with other pollutants in the atmosphere, it can induce smog, photochemical smog, and acid rain.

[0004] Traditional denitrification technologies, especially selective catalytic reduction (SCR), often face problems such as catalyst poisoning and low reaction efficiency in high-sulfur flue gas environments. Furthermore, non-ferrous metal smelting processes consume large amounts of coal. Therefore, developing a highly efficient denitrification technology for treating high-sulfur flue gas from non-ferrous metal smelting is of significant practical importance for promoting green and sustainable development. Summary of the Invention

[0005] This invention provides a method for denitrification of high-sulfur flue gas from non-ferrous metal smelting. The system of this invention can achieve efficient denitrification of high-sulfur flue gas from non-ferrous metal smelting.

[0006] The present invention provides a system for denitrification of high-sulfur flue gas from non-ferrous metal smelting, comprising a first heat exchanger 102, a second heat exchanger 105, and a third heat exchanger 107.

[0007] An electrostatic precipitator 104 is connected to the first outlet of the first heat exchanger 102;

[0008] The electrostatic precipitator 104 is connected to the first inlet of the second heat exchanger 105;

[0009] The first outlet of the second heat exchanger 105 is connected to the second inlet of the first heat exchanger 102;

[0010] A denitrification reactor 106 connected to the second outlet of the first heat exchanger 102;

[0011] The denitrification reactor 106 is connected to the second inlet of the second heat exchanger 105;

[0012] The second outlet of the second heat exchanger 105 is connected to the first inlet of the third heat exchanger 107;

[0013] A dynamic wave scrubber 108 is connected to the first outlet of the third heat exchanger 107.

[0014] Preferably, it also includes: an oxygen tank or an air tank connected to the second inlet of the third heat exchanger 107;

[0015] The non-ferrous metal smelting apparatus 101, which is connected to the second outlet of the third heat exchanger 107, is used to use the oxygen or air after heat exchange in the third heat exchanger 107 for non-ferrous metal smelting.

[0016] The outlet of the non-ferrous metal smelting apparatus 101 is connected to the first inlet of the first heat exchanger 102.

[0017] The first outlet of the third heat exchanger 107 is also connected to the pipeline between the non-ferrous metal smelting device 101 and the first heat exchanger 102, so that the heat-exchanged flue gas is used to regulate the temperature of the high-sulfur flue gas in non-ferrous metal smelting.

[0018] It also includes a sulfur resource recovery device connected to the power wave scrubber 108.

[0019] Preferably, the first outlet of the first heat exchanger 102 is connected to the electrostatic precipitator 104 via the waste heat boiler 103.

[0020] This invention also provides a method for denitrifying high-sulfur flue gas from non-ferrous metal smelting, characterized in that it is carried out in the system described in the above technical solution, and includes the following steps:

[0021] The high-sulfur flue gas from non-ferrous metal smelting is passed into the first heat exchanger 102 for first cooling to obtain cooled flue gas.

[0022] The cooled flue gas is passed into the electrostatic precipitator 104 for electrostatic dust removal to obtain dust-removed flue gas.

[0023] The dust removal flue gas is successively fed into the second heat exchanger 105 and the first heat exchanger 102, and then heated to the first and second temperatures respectively. The resulting dust removal flue gas is then fed into the denitrification reactor 106 for denitrification to obtain denitrified flue gas.

[0024] The denitrified flue gas is passed into the second heat exchanger 105 for a second cooling process to obtain cooled denitrified flue gas.

[0025] The cooled denitrification flue gas is passed into the third heat exchanger 107 for a third cooling, and then into the dynamic wave scrubber 108 for scrubbing.

[0026] Preferably, the washing process further includes: passing the washed flue gas into a sulfur resource recovery device.

[0027] Preferably, by volume fraction, the high-sulfur flue gas from non-ferrous metal smelting comprises 75-80% N2, 3-12% sulfur dioxide, 0.01-0.1% nitrogen oxides, 0-5% carbon dioxide, 0.5-2% carbon monoxide, 1-2% H2O, 3-5% oxygen, and 200-600 mg / m³ 3 Particulate matter and unavoidable metal vapors;

[0028] The temperature of the high-sulfur flue gas from the non-ferrous metal smelting is 850~950℃, and the temperature of the cooled flue gas is 750~780℃.

[0029] The temperature of the dust removal flue gas is 400~430℃.

[0030] Preferably, the temperature of the dust removal flue gas after the first heating is 460~490℃; the temperature of the dust removal flue gas after the second heating is 520~540℃, and the temperature of the denitrification flue gas is 500~520℃.

[0031] Preferably, the catalyst used for denitrification includes Fe-ZSM-5 and / or Fe-Beta catalyst, and the reducing agent used for denitrification includes ammonia and / or urea.

[0032] Preferably, the temperature of the denitrified flue gas after cooling is 340~360℃, and the temperature of the denitrified flue gas obtained by the third cooling is 150~180℃.

[0033] Preferably, the third cooling includes: introducing the cooled denitrification flue gas and oxygen into the third heat exchanger 107 or introducing the cooled denitrification flue gas and air into the third heat exchanger 107; the temperature of the oxygen or air is 10~30℃.

[0034] The system of this invention can realize the denitrification reaction of high-sulfur flue gas from non-ferrous metal smelting, thereby achieving NO reduction. x The removal of particulate matter is achieved, and the generated nitrogen gas is environmentally friendly; the electrostatic precipitator removes particulate matter, and the denitrification reactor removes NO. x The removal of pollutants and the washing of the dynamic wave scrubber can achieve efficient denitrification. In addition, a second heat exchanger 105 is added for secondary heat exchange, making full use of the flue gas temperature, increasing the output of high-temperature steam, reducing the evaporation of water in the scrubber, and reducing costs.

[0035] In addition, NO x The efficient governance effectively avoids NOx Along with SO2, it is oxidized and absorbed, transforming into the byproduct HNO3. This helps to improve the purity of the sulfuric acid product obtained from subsequent acid production processes and enhance economic benefits.

[0036] Furthermore, Fe-ZSM-5 and / or Fe-Beta catalysts are suitable for high-sulfur flue gas conditions, and NO x The removal efficiency is over 90%, which can effectively control NOx and achieve NOx emission standards. It uses NH3 or CO(NH2)2 as a reducing agent, and the products are N2 and H2O, which are clean and pollution-free and environmentally friendly.

[0037] Furthermore, oxygen or air is introduced into the non-ferrous smelting process after heat exchange to ensure the full combustion of coal and improve fuel utilization. The reduction in coal consumption can achieve decarbonization.

[0038] Furthermore, the first outlet of the third heat exchanger 107 is connected to the pipeline between the non-ferrous metal smelting device 101 and the first heat exchanger 102, so that the heat-exchanged flue gas is used as the power to regulate the temperature of the high-sulfur flue gas in non-ferrous metal smelting, ensuring the stable operation of the system. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the system used in the embodiment. Detailed Implementation

[0040] The present invention provides a system for denitrification of high-sulfur flue gas from non-ferrous metal smelting, comprising a first heat exchanger 102, a second heat exchanger 105, and a third heat exchanger 107.

[0041] An electrostatic precipitator 104 is connected to the first outlet of the first heat exchanger 102;

[0042] The electrostatic precipitator 104 is connected to the first inlet of the second heat exchanger 105;

[0043] The first outlet of the second heat exchanger 105 is connected to the second inlet of the first heat exchanger 102;

[0044] A denitrification reactor 106 connected to the second outlet of the first heat exchanger 102;

[0045] The denitrification reactor 106 is connected to the second inlet of the second heat exchanger 105;

[0046] The second outlet of the second heat exchanger 105 is connected to the first inlet of the third heat exchanger 107;

[0047] A dynamic wave scrubber 108 is connected to the first outlet of the third heat exchanger 107.

[0048] The denitrification system for high-sulfur flue gas from non-ferrous metal smelting provided by the present invention includes a first heat exchanger 102; an electrostatic precipitator 104 connected to a first outlet of the first heat exchanger 102; the first outlet of the first heat exchanger 102 and the electrostatic precipitator 104 are preferably connected via a waste heat boiler 103. The electrostatic precipitator 104 preferably uses high-temperature resistant and corrosion-resistant stainless steel as its shell material and is cleaned using a mechanical vibration cleaning method.

[0049] In this invention, the electrostatic precipitator 104 is connected to the first inlet of the second heat exchanger 105; the first outlet of the second heat exchanger 105 is connected to the second inlet of the first heat exchanger 102. The second heat exchanger 105 is connected to the first heat exchanger 102 to perform secondary heat exchange, making full use of the flue gas temperature and reducing costs. Specifically, by adding a second heat exchanger 105 to perform secondary heat exchange, the flue gas temperature is fully utilized and costs are reduced: (1) The flue gas (400~430℃) after electrostatic precipitator passes directly through the first heat exchanger 102 and then enters the denitrification reactor (520~540℃). Correspondingly, the flue gas temperature entering the waste heat boiler through the first heat exchanger 102 decreases, reducing the production of high-temperature steam and reducing economic benefits; (2) The flue gas (500~520℃) after denitrification passes directly through the third heat exchanger 107 and enters the dynamic wave scrubber. The flue gas temperature at the inlet of the dynamic wave scrubber is greatly increased, which will accelerate the evaporation of water in the scrubber and thus increase costs.

[0050] In this invention, a denitrification reactor 106 is connected to the second outlet of the first heat exchanger 102; the denitrification reactor 106 is connected to the second inlet of the second heat exchanger 105.

[0051] The denitrification system for high-sulfur flue gas in non-ferrous metal smelting provided by the present invention preferably further includes: an oxygen tank or an air tank connected to the second inlet of the third heat exchanger 107; and a non-ferrous metal smelting apparatus 101 connected to the second outlet of the third heat exchanger 107, which uses the oxygen or air after heat exchange in the third heat exchanger 107 for non-ferrous metal smelting.

[0052] The non-ferrous metal smelting apparatus 101 is connected to the first inlet of the first heat exchanger 102.

[0053] The first outlet of the third heat exchanger 107 is also connected to the pipeline between the non-ferrous metal smelting apparatus 101 and the first heat exchanger 102, thereby regulating the temperature of the high-sulfur flue gas from the non-ferrous metal smelting process by introducing a portion of the flue gas between the smelting flue gas inlet and the pipeline of the first heat exchanger 102. When the smelting flue gas temperature is too high, this helps to regulate the flue gas temperature and maintain stable operation.

[0054] This invention also provides a method for denitrifying high-sulfur flue gas from non-ferrous metal smelting, carried out in the system described above, and includes the following steps:

[0055] The high-sulfur flue gas from non-ferrous metal smelting is passed into the first heat exchanger 102 for first cooling to obtain cooled flue gas.

[0056] The cooled flue gas is passed into the electrostatic precipitator 104 for electrostatic dust removal to obtain dust-removed flue gas.

[0057] The dust removal flue gas is successively passed into the second heat exchanger 105 and the first heat exchanger 102. After the first heating and the second heating, the resulting dust removal flue gas is passed into the denitrification reactor 106 for denitrification to obtain denitrified flue gas.

[0058] The denitrified flue gas is passed through the second heat exchanger 105 for a second cooling process to obtain cooled denitrified flue gas.

[0059] The heated denitrification flue gas is passed into the third heat exchanger 107 for third cooling and then into the dynamic wave scrubber 108 for washing. The washed mixed flue gas is then passed into the sulfur resource recovery device.

[0060] In this invention, high-sulfur flue gas from non-ferrous metal smelting is introduced into the first heat exchanger 102 for first cooling to obtain cooled flue gas.

[0061] In this invention, the high-sulfur flue gas from non-ferrous metal smelting preferably comprises, by volume fraction: 75-80% N2, 3-12% sulfur dioxide, 0.01-0.1% nitrogen oxides, 0-5% carbon dioxide, 0.5-2% carbon monoxide, 1-2% H2O, 3-5% oxygen, and 200-600 mg / m³. 3 Particulate matter and unavoidable metal vapors, preferably including 76-78% N2, 5-8% sulfur dioxide, 0.04-0.08% nitrogen oxides, 2-4% carbon dioxide, 1.2-1.5% carbon monoxide, 1.2-1.5% H2O, 3.5-4% oxygen, and 400-500 mg / m³ 3 Particulate matter and unavoidable metal vapors.

[0062] In this invention, the temperature of the high-sulfur flue gas from non-ferrous metal smelting is preferably 850~950℃. In specific embodiments of this invention, the temperature of the high-sulfur flue gas from non-ferrous metal smelting can be 850℃, 900℃ or 950℃.

[0063] In this invention, the temperature of the cooling flue gas is 750~780℃. In specific embodiments of this invention, the temperature of the cooling flue gas can be 750℃, 760℃, 770℃, or 780℃.

[0064] After obtaining the cooled flue gas, the present invention introduces the cooled flue gas into the electrostatic precipitator 104 for electrostatic dust removal to obtain dust-removed flue gas.

[0065] In this invention, the electric field length of the electrostatic precipitator is preferably 2.5 kV / cm, the operating voltage is preferably 30~50 V, the operating current is preferably 100~400 mA, and the dust concentration in the flue gas after electrostatic precipitator is preferably 24 mg / m³. 3 The preferred efficiency of the electrostatic precipitator is above 95%.

[0066] Electrostatic precipitators remove dust from flue gas, achieving both flue gas purification and preventing dust-laden flue gas from entering the subsequent denitrification reactor, which would cause the denitrification catalyst to be covered by dust and reduce denitrification efficiency.

[0067] In this invention, the temperature of the dust removal flue gas is preferably 400~430℃. In specific embodiments of this invention, the temperature of the dust removal flue gas can be 400℃, 410℃, 420℃ or 430℃.

[0068] When the first outlet of the first heat exchanger 102 in the system is preferably connected to the electrostatic precipitator 104 via a waste heat boiler 103, the cooled flue gas is preferably introduced into the electrostatic precipitator 104 via the waste heat boiler 103 before entering the electrostatic precipitator 104. The cooled flue gas can be used for waste heat recovery via the waste heat boiler 103 to produce high-temperature steam.

[0069] In this invention, the temperature of the flue gas cooled by the waste heat boiler 103 is preferably 440~480℃. In a specific embodiment of this invention, the temperature of the flue gas cooled by the waste heat boiler 103 can be 440℃, 450℃, 460℃, 470℃ or 480℃.

[0070] After obtaining the dust-removed flue gas, the present invention sequentially introduces the dust-removed flue gas into the second heat exchanger 105 and the first heat exchanger 102, respectively, and after the first and second heating processes, the resulting dust-removed flue gas is introduced into the denitrification reactor 106 for denitrification, thereby obtaining denitrified flue gas.

[0071] In this invention, the temperature of the dust-removing flue gas obtained by the first heating is preferably 460~490℃. In a specific embodiment of this invention, the temperature of the dust-removing flue gas obtained by the first heating can be 460℃, 470℃, 480℃ or 490℃; the temperature of the dust-removing flue gas obtained by the second heating is preferably 520~540℃.

[0072] In this invention, the second temperature increase is achieved by heat exchange between the high-sulfur flue gas (850~950℃) from non-ferrous metal smelting and the flue gas (460~490℃) after the first temperature increase.

[0073] In this invention, the denitrification catalyst preferably comprises Fe-ZSM-5 and / or Fe-Beta catalysts, and the reducing agent used for denitrification preferably comprises ammonia and / or urea. The Fe-ZSM-5 and / or Fe-Beta catalysts have anti-sulfur properties, and using ammonia or urea as a reducing agent, NO is denitrated. x It is converted into harmless N2 and water vapor, and the denitrification efficiency can reach over 90%.

[0074] Taking ammonia as an example, the reaction equation for the denitrification is:

[0075] 4NO + 4NH3 + O2 → 4N2 + 6H2O.

[0076] In this invention, the temperature of the denitrification flue gas is preferably 500~520℃.

[0077] Denitrification can eliminate NOx, enabling NOx emissions to meet standards and improving the environment; on the other hand, removing NOx in advance can improve the quality of sulfuric acid, the product obtained from subsequent desulfurization and acid production.

[0078] After obtaining the denitrified flue gas, the present invention passes the denitrified flue gas into the second heat exchanger 105 for a second cooling process to obtain the cooled denitrified flue gas.

[0079] In this invention, the temperature of the cooled denitrification flue gas is preferably 340~360℃. In a specific embodiment of this invention, the temperature of the cooled denitrification flue gas can be 340℃, 350℃ or 360℃.

[0080] The cooling is achieved through heat exchange between the denitrification flue gas (500~520℃) and the dust removal flue gas (400~430℃).

[0081] After obtaining the cooled denitrified flue gas, the present invention introduces the heated denitrified flue gas into the third heat exchanger 107 for third cooling and then into the dynamic wave scrubber 108 for washing. The washed mixed flue gas is then introduced into the sulfur resource recovery device.

[0082] In this invention, the temperature of the denitrified flue gas after heat exchange is preferably 150~180℃.

[0083] When the denitrified flue gas obtained from the third cooling is introduced into the dynamic wave scrubber 108, the denitrified flue gas after the third cooling preferably enters from top to bottom through the dynamic wave scrubber pipe 108; the scrubbing liquid of the dynamic wave scrubber 108 is preferably injected from bottom to top through the upper and lower nozzles by a pipeline pump. The bottom-to-top injection creates a countercurrent collision of the gas and liquid phases, and the full contact between the gas and liquid can effectively remove SO2 and residual trace amounts of NO. x And dust particles.

[0084] If the heated denitrification flue gas directly enters the dynamic wave scrubber through the third heat exchanger 107, the flue gas temperature at the inlet of the dynamic wave scrubber will be greatly increased, which will accelerate the evaporation of water in the scrubber and thus increase the cost. However, by passing through the second heat exchanger 105 and the third heat exchanger 107, the flue gas temperature can be reduced, thereby reducing the cost.

[0085] When the system further includes: an oxygen tank or air tank connected to the second inlet of the third heat exchanger 107; the non-ferrous metal smelting apparatus 101 connected to the first heat exchanger 102; and the first outlet of the third heat exchanger 107 also connected to a pipeline between the non-ferrous metal smelting apparatus 101 and the first heat exchanger 102:

[0086] The third cooling method preferably includes: introducing oxygen from the oxygen tank or air from the air tank into the third heat exchanger 107 together with the cooled denitrification flue gas to achieve the third cooling of the cooled denitrification flue gas and the heating of the oxygen or air.

[0087] The temperature of the oxygen in the oxygen tank or the air in the air tank is preferably 10~30℃; the temperature of the heated oxygen or air is preferably 110~140℃. The heated oxygen or air can enter the non-ferrous metal smelting device 101 through the second outlet for non-ferrous metal smelting, ensuring the full combustion of coal, improving fuel utilization and reducing coal consumption, so as to achieve low carbonization.

[0088] The denitrified flue gas obtained from the third cooling process is introduced into the pipeline between the non-ferrous metal smelting device 101 and the first heat exchanger 102 to cool the high-sulfur flue gas from the non-ferrous metal smelting process.

[0089] This invention can efficiently remove NO x This avoids the subsequent oxidation and absorption along with SO2 to generate the byproduct HNO3, which is beneficial to improving the quality of sulfuric acid obtained from the non-ferrous smelting flue gas sulfuric acid production process.

[0090] The following detailed description of the system and method for denitrification of high-sulfur flue gas in non-ferrous metal smelting provided by the present invention, with reference to the embodiments, should not be construed as limiting the scope of protection of the present invention.

[0091] The system diagram used in the embodiment is as follows: Figure 1 As shown:

[0092] First heat exchanger 102, second heat exchanger 105, third heat exchanger 107;

[0093] An electrostatic precipitator 104 is connected to the first outlet of the first heat exchanger 102;

[0094] The electrostatic precipitator 104 is connected to the first inlet of the second heat exchanger 105;

[0095] The first outlet of the second heat exchanger 105 is connected to the second inlet of the first heat exchanger 102;

[0096] A denitrification reactor 106 connected to the second outlet of the first heat exchanger 102;

[0097] The denitrification reactor 106 is connected to the second inlet of the second heat exchanger 105;

[0098] The second outlet of the second heat exchanger 105 is connected to the first inlet of the third heat exchanger 107;

[0099] A dynamic wave scrubber 108 is connected to the first outlet of the third heat exchanger 107;

[0100] A sulfur resource recovery device connected to the power wave scrubber 108.

[0101] An oxygen tank or air tank connected to the second inlet of the third heat exchanger 107;

[0102] The second outlet of the third heat exchanger 107 is connected to the non-ferrous metal smelting apparatus 101, and the oxygen or air after heat exchange is used for non-ferrous metal smelting.

[0103] The non-ferrous metal smelting apparatus 101 is connected to the first inlet of the first heat exchanger 102.

[0104] The first outlet of the third heat exchanger 107 is also connected to the pipeline between the non-ferrous metal smelting device 101 and the first heat exchanger 102, for regulating the temperature of the high-sulfur flue gas from non-ferrous metal smelting by the flue gas after heat exchange.

[0105] The first outlet of the first heat exchanger 102 is connected to the electrostatic precipitator 104 via the waste heat boiler 103. Example 1

[0106] Copper smelting flue gas at 850℃ (by volume fraction: 78% N2, 10% SO2, 0.08% NOx, 3% O2, 2% CO, 1.2% H2O, 520 mg / m³) 3 Particulate matter and other unavoidable metal vapors) at 100,000 Nm 3 The flue gas, flowing at a rate of [flow rate] / h, first passes through a heat exchanger to reduce its temperature to 750℃. Then, it is fed into a waste heat boiler for heat recovery. The resulting high-temperature steam serves as a heat carrier for power generation, heating, and domestic use, achieving 30% waste heat utilization. Some heat is lost, and the outlet flue gas temperature is 450℃. The flue gas then enters an electrostatic precipitator to remove 96% of the dust. After dust removal, the gas volume content remains unchanged, but the particulate matter content is reduced to 21 mg / m³. 3The particulate matter contains 35% CuO by mass, with the remainder being Fe2O3, PbO, ZnO, CuSO4, PbSO4, Cd, As, carbon black, and other complex compounds. The temperature is 410℃. To reach the denitrification temperature, the flue gas is introduced into a heat exchanger to raise the temperature to 550℃. The flue gas then flows into the SCR denitrification reactor, where it is mixed with a flow rate of 80 m³ / h. 3 The reducing gas NH3 (25℃) is thoroughly mixed at a rate of / h (the molar ratio of ammonia to NOx is controlled at 1:1), and the mixture is subjected to a reaction time of 8000h. -1 Fully contact with 15000 kg Fe-ZSM-5 (Fe loading: 2wt%, specific surface area: 450 m² / g, pore volume: 0.30 cm⁻¹) at a space velocity. 3 / g), after catalytic reduction (reaction temperature 550℃, time 0.6s), harmless N2 and H2O were obtained, and the NOx removal efficiency reached 92%.

[0107] Because the flue gas temperature after denitrification is relatively high, oxygen-enriched air (65% oxygen by volume) at 20°C is introduced for heat exchange. This oxygen-enriched air is then introduced into the preceding non-ferrous metal smelting process to supply oxygen, reducing the flue gas temperature to 170°C, resulting in low-temperature flue gas. A portion of this low-temperature flue gas is introduced between the smelting flue gas inlet and the heat exchanger to regulate the flue gas temperature, while another portion is introduced into a dynamic wave scrubber to effectively remove residual particulate matter and gaseous pollutants using dynamic waves. Finally, sulfur resources are recovered and utilized. Example 2

[0108] Zinc smelting flue gas at 900℃ (by volume fraction: 78% N2, 9% SO2, 0.06% NOx, 5% O2, 2% CO, 1.0% H2O, 2% CO2, 500 mg / m³) 3 Particulate matter and other unavoidable metal vapors) at 60,000 Nm 3 h -1 The flue gas first passes through a heat exchanger to reduce its temperature to 820℃, then is fed into a waste heat boiler for waste heat recovery. The resulting high-temperature steam serves as a heat carrier for power generation, heating, and domestic use, achieving 35% waste heat utilization. The outlet flue gas temperature is 460℃. The flue gas then enters an electrostatic precipitator to remove 95% of the dust. After dust removal, the gas volume content remains unchanged, but the particulate matter content is reduced to 25 mg / m³. 3 The particulate matter contains 40% ZnO by mass, with the remainder being ZnS, ZnSO4, Cd, As, carbon black, and other complex compounds. The temperature is 420℃. To reach the denitrification temperature, the flue gas is introduced into a heat exchanger to raise the temperature to 560℃. The flue gas then flows into the SCR denitrification reactor, where it is mixed with a flow rate of 36m³.3 The reducing gas NH3 (with a molar ratio of ammonia to NOx controlled at 1) is thoroughly mixed at a rate of / h and subjected to 10000 h. -1 9000 kg of Fe-Beta catalyst (Fe content: 3wt%, specific surface area: 560 m²) was fully contacted at a space velocity. 2 / g, pore volume: 0.4cm³ 3 ( / g) (reaction temperature 560℃, time 0.6s), efficiently converted into N2 and H2O. By optimizing the amount of reducing agent ammonia, the NOx removal efficiency reached 92%. The elimination of NOx greatly reduced the possibility of the formation of byproduct HNO3.

[0109] Because the flue gas temperature after denitrification is relatively high, oxygen-enriched air (65% oxygen by volume) at 25°C is introduced for heat exchange, reducing the flue gas temperature to 170°C, resulting in low-temperature flue gas. This oxygen-enriched air is then introduced into the preceding non-ferrous smelting process to supply oxygen, reducing coal consumption and promoting decarbonization. A portion of the low-temperature flue gas is introduced between the smelting flue gas inlet and the heat exchanger to regulate the flue gas temperature, while another portion is introduced into a dynamic wave scrubber to effectively remove residual particulate matter and gaseous pollutants using dynamic waves. Finally, sulfur resources are recovered and utilized. Example 3

[0110] Lead smelting flue gas at 950℃ (by volume fraction: 76% N2, 9% SO2, 0.05% NOx, 5% O2, 1% CO, 1.2% H2O, 2% CO2, 500 mg / m³) 3 Particulate matter and other unavoidable metal vapors) at 100,000 Nm 3 The flue gas, with a flow rate of [flow rate] / h, first passes through a heat exchanger to reduce its temperature to 850℃. Then, it is fed into a waste heat boiler for waste heat recovery. The resulting high-temperature steam serves as a heat carrier for power generation, heating, and domestic use, achieving 35% waste heat utilization. The outlet flue gas temperature is 480℃. After waste heat recovery, the flue gas undergoes an electrostatic precipitator, achieving a particulate matter removal rate of up to 95%. After dust removal, the flue gas (gas volume content remains unchanged, but particulate matter content is reduced to 25 mg / m³) 3 The particulate matter contains 50% PdO by mass, with the remainder being PdS, PdSO4, PdCO3, ZnO, CuO, Cd, carbon black, and other complex compounds. The temperature is 430 ℃. The flue gas is introduced into a heat exchanger to raise the temperature to 550 ℃ before flowing into the SCR denitrification reactor, where a flow rate of 55 m³ / h is used. 3 The reducing gas NH3 is thoroughly mixed at a rate of / h (the molar ratio of ammonia to NOx is controlled at 1:1.1), and the mixture is subjected to a reaction at a rate of / h for 10000h. -112000 kg of Fe-ZSM-5 catalyst (Fe content: 3 wt%, specific surface area: 400 m²) was fully contacted at a space velocity. 2 / g, pore volume: 0.25cm³ 3 / g), which was catalytically reduced (reaction temperature 550℃, time 0.5s) to obtain products N2 and H2O, with NOx removal efficiency reaching 90%.

[0111] Because the flue gas temperature after denitrification is relatively high, oxygen at 20°C is introduced for gas-to-gas heat exchange, reducing the flue gas temperature to 180°C, resulting in low-temperature flue gas. This oxygen-enriched air is then introduced into the preceding non-ferrous smelting process to supply oxygen, reducing coal consumption and promoting decarbonization. A portion of the low-temperature flue gas is introduced between the smelting flue gas inlet and the heat exchanger to regulate the flue gas temperature, while another portion is introduced into a dynamic wave scrubber to effectively remove residual particulate matter and gaseous pollutants using dynamic waves. Finally, sulfur resources are recovered and utilized.

[0112] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A system for denitrifying high-sulfur flue gas from non-ferrous metal smelting, characterized in that, It includes a first heat exchanger (102), a second heat exchanger (105), and a third heat exchanger (107). An electrostatic precipitator (104) is connected to the first outlet of the first heat exchanger (102). The electrostatic precipitator (104) is connected to the first inlet of the second heat exchanger (105); The first outlet of the second heat exchanger (105) is connected to the second inlet of the first heat exchanger (102); A denitrification reactor (106) connected to the second outlet of the first heat exchanger (102). The denitrification reactor (106) is connected to the second inlet of the second heat exchanger (105); The second outlet of the second heat exchanger (105) is connected to the first inlet of the third heat exchanger (107); A dynamic wave scrubber (108) is connected to the first outlet of the third heat exchanger (107). It also includes: an oxygen tank or an air tank connected to the second inlet of the third heat exchanger (107); A non-ferrous metal smelting apparatus (101) connected to the second outlet of the third heat exchanger (107) is used to smelt oxygen or air after heat exchange in the third heat exchanger (107) for non-ferrous metal smelting. The outlet of the non-ferrous metal smelting apparatus (101) is connected to the first inlet of the first heat exchanger (102); The first outlet of the third heat exchanger (107) is also connected to the pipeline between the non-ferrous metal smelting device (101) and the first heat exchanger (102), so that the flue gas after heat exchange is used to regulate the temperature of high sulfur flue gas in non-ferrous metal smelting. It also includes: a sulfur resource recovery device connected to the power wave scrubber (108); The first outlet of the first heat exchanger (102) is connected to the electrostatic precipitator (104) via a waste heat boiler (103); The method for denitrifying high-sulfur flue gas from non-ferrous metal smelting using the aforementioned system includes the following steps: The high-sulfur flue gas from non-ferrous metal smelting is passed into the first heat exchanger (102) for first cooling to obtain cooled flue gas; The cooled flue gas is passed into an electrostatic precipitator (104) for electrostatic precipitation to obtain dust-removed flue gas; The dust removal flue gas is successively fed into the second heat exchanger (105) and the first heat exchanger (102) for a first heating and a second heating, and then the resulting dust removal flue gas is fed into the denitrification reactor (106) for denitrification to obtain denitrified flue gas; The denitrified flue gas is passed into the second heat exchanger (105) for a second cooling to obtain cooled denitrified flue gas; The cooled denitrification flue gas is passed into the third heat exchanger (107) for a third cooling and then passed into the dynamic wave scrubber (108) for scrubbing; The washing process also includes: passing the washed flue gas into a sulfur resource recovery device.

2. The system according to claim 1, characterized in that, The temperature of the high-sulfur flue gas from the non-ferrous metal smelting is 850~950℃, and the temperature of the cooled flue gas is 750~780℃. The temperature of the dust removal flue gas is 400~430℃.

3. The system according to claim 1, characterized in that, The temperature of the dust removal flue gas after the first heating is 460~490℃; the temperature of the dust removal flue gas after the second heating is 520~540℃, and the temperature of the denitrification flue gas is 500~520℃.

4. The system according to claim 1, characterized in that, The catalyst used for denitrification includes Fe-ZSM-5 and / or Fe-Beta catalyst, and the reducing agent used for denitrification includes ammonia and / or urea.

5. The system according to claim 1, characterized in that, The temperature of the denitrified flue gas after cooling is 340~360℃, and the temperature of the denitrified flue gas obtained by the third cooling is 150~180℃.

6. The system according to claim 1, characterized in that, The third cooling process includes: introducing the cooled denitrified flue gas and oxygen into the third heat exchanger (107) or introducing the cooled denitrified flue gas and air into the third heat exchanger (107); the temperature of the oxygen or air is 10~30℃.

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