Denitration system and method for non-ferrous metal metallurgy high-sulfur flue gas

Abstract

The invention provides a system and a method for denitrifying high-sulfur flue gas in non-ferrous metal metallurgy, and belongs to the field of industrial waste gas treatment. The invention provides a high-sulfur flue gas denitration system for non-ferrous metal metallurgy. The system comprises a heat exchanger 102, a heat exchanger 105 and a heat exchanger 107, the electric dust remover 104 is connected with a first outlet of the heat exchanger 102; the electric dust remover 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; the denitration reactor 106 is 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 the dynamic wave scrubber 108 is connected with a first outlet of the heat exchanger 107.

Description

Technical Field

[0001] The present invention relates to the field of industrial waste gas treatment, and in particular to a system and method for denitrification of high-sulfur flue gas from non-ferrous metal smelting. Background Art

[0002] As an important foundation for the development of modern industry and technology, non-ferrous metal smelting has developed rapidly. With the increasingly stringent global environmental protection requirements, the non-ferrous metal smelting industry faces the dual challenges of how to effectively reduce harmful gas emissions, improve production efficiency and reduce carbon emissions. The flue gas released during the non-ferrous metal smelting process (especially copper, zinc, lead, etc.) contains sulfur dioxide (SO 2 ), nitrogen oxides (NO x ), dust and other air pollutants seriously pollute the environment and pose a threat to human health. Therefore, how to effectively remove NO generated during the smelting process x and SO 2 , which has become a technical problem that needs to be solved urgently in the non-ferrous metal smelting industry.

[0003] Sulfur-rich ores during smelting can result in high levels of SO 2 The generation and emission of SO 2 Generally, it is as high as 3-12%, so people generally pay attention to the removal of sulfur. 2 At the same time, it also realizes the resource utilization of sulfur, while NO x It is not properly treated and is directly discharged with the exhaust gas. x On the one hand, it will be converted into nitric acid (HNO 3 ), which reduces the purity of the sulfuric acid product and reduces economic benefits; on the other hand, NO x Excessive emissions will cause serious environmental problems. x When interacting with other pollutants in the atmosphere, it will induce haze, photochemical smog and acid rain, which will greatly reduce the air quality and endanger human health.

[0004] Traditional denitrification technologies, especially selective catalytic reduction (SCR) technology, often face problems such as catalyst poisoning and low reaction efficiency in high-sulfur flue gas environments. In addition, non-ferrous smelting processes consume a large amount of coal. In order to promote green and sustainable development, it is of great practical significance to develop a denitrification technology that can efficiently treat high-sulfur flue gas from non-ferrous metal smelting. Summary of the invention

[0005] The present invention provides a method for denitrification of high-sulfur flue gas from non-ferrous metal smelting. The system of the present invention can realize 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 in non-ferrous metal smelting, comprising a heat exchanger 102, a heat exchanger 105, and a heat exchanger 107;

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

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

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

[0010] a denitration reactor 106 connected to the second outlet of the heat exchanger 102;

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

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

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

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

[0015] The non-ferrous metal smelting device 101 connected to the second outlet of the heat exchanger 107 is used to use the oxygen or air after heat exchange by the heat exchanger 107 for smelting non-ferrous metals;

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

[0017] The first outlet of the heat exchanger 107 is also connected to the pipeline between the non-ferrous metal smelting device 101 and the heat exchanger 102, and the flue gas after heat exchange is used to control the temperature of the high-sulfur flue gas from the 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 heat exchanger 102 is connected to the electrostatic precipitator 104 via a waste heat boiler 103 .

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

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

[0022] Passing the cooled flue gas into the electrostatic precipitator 104 for electrostatic precipitation to obtain dust-removed flue gas;

[0023] The dust-removed flue gas is successively passed into the heat exchanger 105 and the heat exchanger 102, and after the first heating and the second heating, the obtained dust-removed flue gas is passed into the denitration reactor 106 for denitration to obtain denitration flue gas;

[0024] Passing the denitrified flue gas into the heat exchanger 105 for a second cooling process to obtain the denitrified flue gas after cooling;

[0025] The denitrified flue gas after cooling is passed into the heat exchanger 107 for the third cooling and then passed into the dynamic wave scrubber 108 for washing.

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

[0027] Preferably, the non-ferrous metal smelting high-sulfur flue gas comprises 75-80% N 2 , 3-12% sulfur dioxide, 0.01-0.1% nitrogen oxides, 0-5% carbon dioxide, 0.5-2% carbon monoxide, 1-2% H 2 O, 3-5% oxygen and 200-600 mg / m 3 Particulate matter and unavoidable metal vapor;

[0028] The temperature of the non-ferrous metal smelting high-sulfur flue gas is 850-950°C, and the temperature of the cooling flue gas is 750-780°C;

[0029] The temperature of the dust removal flue gas is 400-430°C.

[0030] Preferably, the temperature of the dust-removed flue gas after the first heating is 460-490°C; the temperature of the dust-removed flue gas after the second heating is 540-570°C, and the temperature of the denitrification flue gas is 520-550°C.

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

[0032] Preferably, the temperature of the denitrification flue gas after the cooling is 340-360°C, and the temperature of the denitrification flue gas obtained by the third cooling is 150-180°C.

[0033] Preferably, the third cooling includes: passing the cooled denitrification flue gas and oxygen or air into a heat exchanger 107; the temperature of the oxygen or air is 10-30°C.

[0034] The system of the present invention can realize the denitration reaction of high-sulfur flue gas in non-ferrous metal smelting, and realize NOx The removal of nitrogen and the generated nitrogen are environmentally friendly; the removal of particles by electrostatic precipitator and the removal of NO by denitrification reactor x The removal of and the washing of the power wave scrubber can achieve efficient denitrification. In addition, the heat exchanger 105 is added for secondary heat exchange, which makes full use of the flue gas temperature, increases the output of high-temperature steam, reduces the evaporation of water in the scrubber, and reduces costs.

[0035] In addition, NO x Efficient governance effectively avoids NO x Follow SO 2 are oxidized and absorbed together and transformed into the byproduct HNO 3 This is conducive to improving the purity of sulfuric acid products obtained in the subsequent acid production process and improving 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 as high as 90% or more, which can effectively control NOx and achieve NOx emission standards. 3 or CO(NH 2 ) 2 As a reducing agent, the product is N 2 and H 2 O, are clean, pollution-free and environmentally friendly.

[0037] Furthermore, oxygen or air is introduced into the nonferrous smelting process after heat exchange to ensure the complete combustion of coal and improve fuel utilization, while the reduction in coal usage can achieve low carbonization.

[0038] Furthermore, the first outlet of the heat exchanger 107 is connected to the pipeline between the non-ferrous metal smelting device 101 and the heat exchanger 102, and the flue gas after heat exchange is used to control the temperature of the high-sulfur flue gas in the non-ferrous metal smelting to ensure the stable operation of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Schematic diagram of the system used in the embodiment. DETAILED DESCRIPTION

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

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

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

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

[0044] a denitration reactor 106 connected to the second outlet of the heat exchanger 102;

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

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

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

[0048] The system for denitrification of high-sulfur flue gas from nonferrous metal smelting provided by the present invention comprises a heat exchanger 102; an electrostatic precipitator 104 connected to a first outlet of the heat exchanger 102; the first outlet of the heat exchanger 102 is preferably connected to the electrostatic precipitator 104 through a waste heat boiler 103. The electrostatic precipitator 104 is preferably made of high-temperature resistant and corrosion-resistant stainless steel as the outer shell material, and is cleaned by a mechanical vibration cleaning method.

[0049] In the present invention, the electrostatic precipitator 104 is connected to the first inlet of the heat exchanger 105; the first outlet of the heat exchanger 105 is connected to the second inlet of the heat exchanger 102. The heat exchanger 105 is connected to the heat exchanger 102 to perform secondary heat exchange, make full use of the flue gas temperature, and reduce costs. Specifically, the heat exchanger 105 is added to perform secondary heat exchange, make full use of the flue gas temperature, and reduce costs: (1) The flue gas (400-430°C) after the electrostatic precipitator directly passes through the heat exchanger 102 (520-540°C) and enters the denitration reactor. The corresponding flue gas temperature entering the waste heat boiler through the heat exchanger 102 is reduced, reducing the output of high-temperature steam and reducing economic benefits; (2) The flue gas (500-520°C) after denitration directly passes through the 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, thereby increasing costs.

[0050] In the present invention, the denitration reactor 106 is connected to the second outlet of the heat exchanger 102 ; the denitration reactor 106 is connected to the second inlet of the heat exchanger 105 .

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

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

[0053] The first outlet of the heat exchanger 107 is also connected to the pipeline between the non-ferrous metal smelting device 101 and the heat exchanger 102, and the flue gas after heat exchange is used to regulate the temperature of the high-sulfur flue gas of non-ferrous metal smelting. Part of the flue gas is introduced between the smelting flue gas inlet and the pipeline of the heat exchanger 102. When the smelting flue gas temperature is too high, it plays a role in regulating the flue gas temperature and maintaining stable operation.

[0054] The present invention also provides a method for denitrification of high-sulfur flue gas from non-ferrous metal smelting, which is carried out in the system described in the above technical solution and comprises the following steps:

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

[0056] Passing the cooled flue gas into the electrostatic precipitator 104 for electrostatic precipitation to obtain dust-removed flue gas;

[0057] The dust-removed flue gas is successively passed into the heat exchanger 105 and the heat exchanger 102, and after the first heating and the second heating, the obtained dust-removed flue gas is passed into the denitration reactor 106 for denitration to obtain denitration flue gas;

[0058] The denitrified flue gas is successively introduced into the heat exchanger 105 for a second cooling to obtain the denitrified flue gas after cooling;

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

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

[0061] In the present invention, the non-ferrous metal smelting high-sulfur flue gas preferably comprises 75-80% N 2 , 3-12% sulfur dioxide, 0.01-0.1% nitrogen oxides, 0-5% carbon dioxide, 0.5-2% carbon monoxide, 1-2% H 2 O, 3-5% oxygen and 200-600 mg / m 3 Particles and inevitable metal vapor, more preferably including 76-78% N 2 , 5-8% sulfur dioxide, 0.04-0.08% nitrogen oxides, 2-4% carbon dioxide, 1.2-1.5% carbon monoxide, 1.2-1.5% H 2 O, 3.5-4% oxygen and 400-500 mg / m 3Particles and unavoidable metal vapor.

[0062] In the present invention, the temperature of the high-sulfur flue gas from non-ferrous metal smelting is preferably 850-950°C. In a specific embodiment of the present invention, the temperature of the high-sulfur flue gas from non-ferrous metal smelting can be 850°C, 900°C or 950°C.

[0063] In the present invention, the temperature of the cooling flue gas is 750-780°C. In a specific embodiment of the present invention, the temperature of the cooling flue gas can be 750°C, 760°C, 770°C or 780°C.

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

[0065] In the present invention, the electric field length of the electrostatic precipitator is preferably 2.5 kV / cm, the working voltage is preferably 30-50 V, the working current is preferably 100-400 mA, and the dust concentration in the flue gas after the electrostatic precipitator is preferably 24 mg / m 3 Hereinafter, the efficiency of the electrostatic precipitator is preferably above 95%.

[0066] On the one hand, electrostatic precipitator removes dust from flue gas to purify the flue gas. On the other hand, it can prevent dusty flue gas from entering the subsequent denitrification reactor, causing the denitrification catalyst to be covered by dust, resulting in a decrease in denitrification efficiency.

[0067] In the present invention, the temperature of the dust removal flue gas is preferably 400-430°C. In a specific embodiment of the present invention, the temperature of the dust removal flue gas may be 400°C, 410°C, 420°C or 430°C.

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

[0069] In the present invention, the temperature of the cooled flue gas passing through the waste heat boiler 103 is preferably 440-480°C. In a specific embodiment of the present invention, the temperature of the cooled flue gas passing through the waste heat boiler 103 may be 440°C, 450°C, 460°C, 470°C or 480°C.

[0070] After obtaining the dust-removed flue gas, the present invention successively passes the dust-removed flue gas into the heat exchanger 105 and the heat exchanger 102, respectively, and then passes the obtained dust-removed flue gas into the denitration reactor 106 for denitration to obtain the denitration flue gas.

[0071] In the present invention, the temperature of the dust-removed flue gas obtained by the first heating is preferably 460-490°C. In a specific embodiment of the present invention, the temperature of the dust-removed flue gas obtained by the first heating can be 460°C, 470°C, 480°C or 490°C; the temperature of the dust-removed flue gas obtained by the second heating is preferably 540-570°C. In a specific embodiment of the present invention, the temperature of the dust-removed flue gas obtained by the second heating can be 540°C, 550°C, 560°C or 570°C.

[0072] In the present invention, the second heating is achieved by heat exchange between high-sulfur flue gas (850-950° C.) from non-ferrous metal smelting and the flue gas (460-490° C.) after the first heating.

[0073] In the present invention, the denitration catalyst preferably includes Fe-ZSM-5 and / or Fe-Beta catalyst, and the denitration reducing agent preferably includes ammonia and / or urea. Fe-ZSM-5 and / or Fe-Beta catalysts have sulfur resistance. Ammonia or urea is used as a reducing agent to reduce NO x Converted to harmless N 2 and water vapor, the denitrification efficiency can reach over 90%.

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

[0075] 4NO+4NH 3 +O 2 →4N 2 +6H 2 O.

[0076] In the present invention, the temperature of the denitrification flue gas is preferably 520-550°C. In a specific embodiment of the present invention, the temperature of the denitrification flue gas may be 520°C, 530°C, 540°C or 550°C.

[0077] On the one hand, denitrification can eliminate NOx, so that NOx emissions meet standards and improve the environment; on the other hand, it can remove NOx in advance and improve the quality of the subsequent sulfuric acid product obtained from desulfurization and acid production.

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

[0079] In the present invention, the temperature of the denitrification flue gas after cooling is preferably 340-360°C. In a specific embodiment of the present invention, the temperature of the denitrification flue gas after cooling can be 340°C, 350°C or 360°C.

[0080] The temperature reduction is achieved by heat exchange between the denitrification flue gas (500-520°C) and the dust removal flue gas (400-430°C).

[0081] After obtaining the denitrification flue gas after cooling, the present invention passes the heated denitrification flue gas into the heat exchanger 107 for a third cooling and then into the dynamic wave scrubber 108 for washing, and then passes the washed mixed flue gas into the sulfur resource recovery device.

[0082] In the present invention, the temperature of the denitrification flue gas after heat exchange is preferably 150-180°C.

[0083] When the denitrified flue gas obtained by the third cooling is passed into the power wave scrubber 108, the denitrified flue gas after the third cooling preferably enters from the power wave scrubbing pipe 108 from top to bottom; the scrubbing liquid of the power wave scrubber 108 is preferably sprayed from the upper nozzle and the lower nozzle from bottom to top through a pipeline pump. The spraying from bottom to top forms a countercurrent collision of the gas and liquid phases, and the gas and liquid fully contact to fully remove SO 2 and residual trace NO x and dust particles.

[0084] If the heated denitrification flue gas directly passes through the heat exchanger 107 and enters the dynamic wave scrubber, the inlet flue gas temperature 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, passing through the heat exchangers 105 and 107 can reduce the flue gas temperature and reduce the cost.

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

[0086] The third cooling preferably includes: passing the oxygen in the oxygen tank or the air in the air tank and the denitrification flue gas after the temperature is reduced into the heat exchanger 107 to achieve the third cooling of the denitrification flue gas after the temperature is reduced 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 independently 10-30°C; the temperature of the heated oxygen or air is preferably 110-140°C. The heated oxygen or air can enter the non-ferrous metal smelting device 101 through the second outlet for non-ferrous metal smelting, thereby ensuring sufficient combustion of coal, improving fuel utilization and reducing coal usage to achieve low carbonization.

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

[0089] The present invention can effectively remove NO x , to avoid subsequent SO 2Oxidation and absorption to generate byproduct HNO 3 , which is beneficial to improving the quality of sulfuric acid obtained from the non-ferrous smelting flue gas acid production process.

[0090] The system and method for denitrification of high-sulfur flue gas from non-ferrous metal smelting provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

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

[0092] Heat exchanger 102, heat exchanger 105, heat exchanger 107;

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

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

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

[0096] a denitration reactor 106 connected to the second outlet of the heat exchanger 102;

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

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

[0099] a power wave scrubber 108 connected to a first outlet of the heat exchanger 107;

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

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

[0102] The second outlet of the heat exchanger 107 is connected to the non-ferrous metal smelting device 101, and the heat-exchanged oxygen or air is used for the smelting of non-ferrous metals;

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

[0104] The first outlet of the heat exchanger 107 is also connected to the pipeline between the non-ferrous metal smelting device 101 and the heat exchanger 102, and is used 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 heat exchanger 102 is connected to the electrostatic precipitator 104 via the waste heat boiler 103 .

[0106] Example 1

[0107] 850℃ copper smelting flue gas (78%N by volume fraction) 2 , 10% SO 2 , 0.08% NOx, 3% O 2 , 2% CO, 1.2% H 2 O, 520 mg / m 3 Particles and other unavoidable metal vapor) at 100000Nm 3 The flue gas temperature is first reduced to 750℃ by the heat exchanger with a flow rate of / h. Then the flue gas is passed into the waste heat boiler for waste heat recovery. The high-temperature steam generated is used as a heat carrier for power generation, heating and life, etc., achieving 30% waste heat utilization and partial heat loss. The outlet flue gas temperature is 450℃. The flue gas then enters the electrostatic precipitator to remove 96% of the dust in the flue gas. After dust removal, the flue gas (gas volume content remains unchanged, and the content of particulate matter is reduced to 21mg / m 3 The mass content of CuO in the particles is 35%, and the rest is Fe 2 O 3 、PbO、ZnO、CuSO 4 、PbSO 4 , Cd, As, carbon black and other complex compounds) with a temperature of 410°C. To reach the denitration temperature, the flue gas is introduced into the heat exchanger to raise the temperature to 550°C, and the flue gas flows into the SCR denitration reactor with a flow rate of 80m 3 / h of reducing gas NH 3 (25℃) for full mixing (the molar ratio of ammonia to NOx is controlled at 1:1), and at 8000h -1 15000kg Fe-ZSM-5 (Fe loading: 2wt%, specific surface area: 450m 2 / g, pore volume: 0.30cm 3 / g), and then catalytically reduced (reaction temperature: 550℃, time: 0.6s) to obtain harmless N 2 and H 2 O, NOx removal efficiency reaches 92%.

[0108] Since the flue gas temperature after denitrification is relatively high, oxygen-enriched air (oxygen content of 65% by volume) at a temperature of 20°C is introduced for heat exchange. The oxygen-enriched air after heat exchange is introduced into the previous non-ferrous metal smelting process to supply oxygen, and the flue gas temperature is reduced to 170°C to obtain low-temperature flue gas. The oxygen-enriched air after heat exchange is introduced into the previous non-ferrous metal smelting process to supply oxygen and reduce the use of coal to promote low carbonization; part of the low-temperature flue gas can be introduced between the smelting flue gas inlet and the heat exchanger to modulate the flue gas temperature, and part of the low-temperature flue gas is introduced into the dynamic wave scrubber to effectively remove residual particulate matter and gaseous pollutants using the action of dynamic waves, and finally the sulfur resources are recycled.

[0109] Example 2

[0110] 900℃ zinc smelting flue gas (78%N by volume fraction) 2 , 9% SO 2 , 0.06% NOx, 5% O 2 , 2% CO, 1.0% H 2 O, 2% CO 2 , 500mg / m 3 Particles and other unavoidable metal vapor) at 60000Nm 3 h -1 The flue gas temperature is first reduced to 820℃ by the heat exchanger, and then the flue gas is passed into the waste heat boiler for waste heat recovery. The high-temperature steam generated is used as a heat carrier for power generation, heating and life, etc., achieving 35% waste heat utilization, and the outlet flue gas temperature is 460℃. The flue gas then enters the electrostatic precipitator to remove 95% of the dust in the flue gas. After dust removal, the flue gas (gas volume content remains unchanged, and the content of particulate matter is reduced to 25mg / m 3 The mass content of ZnO in the particles is 40%, and the rest is ZnS, ZnSO 4 , Cd, As, carbon black and other complex compounds) with a temperature of 420°C. To reach the denitration temperature, the flue gas is introduced into the heat exchanger to raise the temperature to 560°C, and the flue gas flows into the SCR denitration reactor with a flow rate of 36m 3 / h of reducing gas NH 3 (The molar ratio of ammonia to NOx is controlled at 1) and mixed thoroughly. -1 The space velocity was sufficient to contact 9000 kg of Fe-Beta catalyst (Fe content: 3 wt%, specific surface area: 560 m 2 / g, pore volume: 0.4cm 3 / g)(reaction temperature is 560℃, time is 0.6s), and it is efficiently converted into N 2 and H 2 O, by optimizing the dosage of reducing agent ammonia, the NOx removal efficiency reaches 92%, the elimination of NOx greatly reduces the by-product HNO3 The possibility of formation.

[0111] Since the flue gas temperature after denitrification is relatively high, oxygen-enriched air (oxygen content of 65% by volume) at a temperature of 25°C is introduced for heat exchange, and the flue gas temperature is reduced to 170°C to obtain low-temperature flue gas. The oxygen-enriched air after heat exchange is introduced into the previous non-ferrous smelting process to supply oxygen and reduce the use of coal to promote low carbonization; part of the low-temperature flue gas can be introduced between the smelting flue gas inlet and the heat exchanger to modulate the flue gas temperature, and part of the low-temperature flue gas is introduced into the dynamic wave scrubber to effectively remove residual particulate matter and gaseous pollutants using the action of dynamic waves, and finally the sulfur resources are recycled.

[0112] Example 3

[0113] 950℃ lead smelting flue gas (76%N by volume) 2 , 9% SO 2 , 0.05% NOx, 5% O 2 , 1% CO, 1.2% H 2 O, 2% CO 2 , 500mg / m 3 Particles and other unavoidable metal vapor) at 100000Nm 3 The flow rate of / h is first reduced to 850℃ by the heat exchanger, and then the flue gas is passed into the waste heat boiler for waste heat recovery. The high-temperature steam generated is used as a heat carrier for power generation, heating and life, etc., achieving 35% waste heat utilization, and the outlet flue gas temperature is 480℃. The flue gas after waste heat recovery is sent to the electrostatic precipitator, and the particle removal rate is as high as 95% of the dust. After dust removal, the flue gas (gas volume content remains unchanged, and the particulate content is reduced to 25mg / m 3 The mass content of PdO in the particles is 50%, and the rest is PdS, PdSO 4 、PdCO 3 , ZnO, CuO, Cd, carbon black and other complex compounds) with a temperature of 430°C. The flue gas is introduced into the heat exchanger to raise the temperature to 550°C and then flows into the SCR denitrification reactor with a flow rate of 55m 3 / h reducing gas NH 3 Mix thoroughly (the molar ratio of ammonia to NOx is controlled at 1:1.1), and -1 12000kg Fe-ZSM-5 catalyst (Fe content: 3wt%, specific surface area: 400m 2 / g, pore volume: 0.25cm 3 / g), and catalytic reduction (reaction temperature: 550℃, time: 0.5s) was performed to obtain product N 2 and H 2O, NOx removal efficiency reaches 90%.

[0114] Since the flue gas temperature after denitrification is relatively high, oxygen at a temperature of 20°C is introduced for gas-to-gas heat exchange, and the flue gas temperature is reduced to 180°C to obtain low-temperature flue gas. The oxygen-enriched air after heat exchange is introduced into the previous non-ferrous smelting process to supply oxygen and reduce the use of coal to promote low carbonization; part of the low-temperature flue gas can be introduced between the smelting flue gas inlet and the heat exchanger to modulate the flue gas temperature, and part of the low-temperature flue gas is introduced into the power wave scrubber to effectively remove residual particulate matter and gaseous pollutants using the action of the power wave, and finally the sulfur resources are recycled.

[0115] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A system for denitrification of high-sulfur flue gas from non-ferrous metal smelting, characterized in that: It includes a heat exchanger (102), a heat exchanger (105), and a heat exchanger (107); an electrostatic precipitator (104) connected to a first outlet of the heat exchanger (102); The electrostatic precipitator (104) is connected to a first inlet of the heat exchanger (105); The first outlet of the heat exchanger (105) is connected to the second inlet of the heat exchanger (102); a denitration reactor (106) connected to the second outlet of the heat exchanger (102); The denitration reactor (106) is connected to the second inlet of the heat exchanger (105); The second outlet of the heat exchanger (105) is connected to the first inlet of the heat exchanger (107); A dynamic wave scrubber (108) is connected to the first outlet of the heat exchanger (107).

2. The system according to claim 1, characterized in that Also includes: an oxygen tank or an air tank connected to the second inlet of the heat exchanger (107); A non-ferrous metal smelting device (101) connected to the second outlet of the heat exchanger (107), used for using the oxygen or air after heat exchange in the heat exchanger (107) for smelting non-ferrous metals; The outlet of the nonferrous metal smelting device (101) is connected to the first inlet of the heat exchanger (102); The first outlet of the heat exchanger (107) is also connected to the pipeline between the non-ferrous metal smelting device (101) and the heat exchanger (102), so that the flue gas after heat exchange is used to control the temperature of the high-sulfur flue gas from the non-ferrous metal smelting; It also includes: a sulfur resource recovery device connected to the power wave scrubber (108).

3. The system according to claim 1, characterized in that The first outlet of the heat exchanger (102) is connected to the electrostatic precipitator (104) via a waste heat boiler (103).

4. A method for denitrification of high-sulfur flue gas from non-ferrous metal smelting, characterized in that: The method is carried out in the system according to any one of claims 1 to 3, comprising the following steps: Passing high-sulfur flue gas from nonferrous metal smelting into the heat exchanger (102) for first cooling to obtain cooled flue gas; Passing the cooled flue gas into an electrostatic precipitator (104) for electrostatic precipitation to obtain dust-removed flue gas; The dust-removed flue gas is successively passed into a heat exchanger (105) and a heat exchanger (102) for first heating and second heating, and then the obtained dust-removed flue gas is passed into a denitration reactor (106) for denitration to obtain denitration flue gas; Passing the denitrified flue gas into a heat exchanger (105) for a second cooling process to obtain denitrified flue gas after cooling; The denitrified flue gas after cooling is passed into a heat exchanger (107) for a third cooling and then passed into a dynamic wave scrubber (108) for washing.

5. The method according to claim 4, characterized in that After the washing, the method further comprises: passing the washed flue gas into a sulfur resource recovery device.

6. The method according to claim 4 or 5, characterized in that: In terms of volume fraction, the non-ferrous metal smelting high-sulfur flue gas includes 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 / m 3 Particulate matter and unavoidable metal vapor; The temperature of the non-ferrous metal smelting high-sulfur flue gas is 850-950°C, and the temperature of the cooling flue gas is 750-780°C; The temperature of the dust removal flue gas is 400-430°C.

7. The method according to claim 1, characterized in that The temperature of the dust-removed flue gas after the first heating is 460-490°C; the temperature of the dust-removed flue gas after the second heating is 540-570°C, and the temperature of the denitrified flue gas is 520-550°C.

8. The method according to claim 4 or 7, characterized in that: The catalyst used for denitration includes Fe-ZSM-5 and / or Fe-Beta catalyst, and the reducing agent used for denitration includes ammonia and / or urea.

9. The method according to claim 4, characterized in that The temperature of the denitrification flue gas after the cooling is 340-360°C, and the temperature of the denitrification flue gas obtained by the third cooling is 150-180°C.

10. The method according to claim 4 or 9, characterized in that: The third cooling includes: passing the denitrification flue gas after the cooling and oxygen or air into a heat exchanger (107); the temperature of the oxygen or air is 10-30°C.

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