Flue gas treatment method for copper-containing sludge smelting furnace and sintering furnace

Abstract

The invention discloses a flue gas treatment method for a copper-containing sludge smelting furnace and a sintering furnace, which comprises the following steps: flue gas from the sintering furnace flows along a first flue gas flowing path and is treated; flue gas from the smelting furnace flows along a second flue gas flowing path and is treated; wherein the sintering furnace is connected with the smelting furnace through the burdening and brickmaking system. According to the flue gas treatment method for the copper-containing sludge smelting furnace and the sintering furnace, the cost can be reduced.

Description

Technical Field

[0001] The invention belongs to the field of harmless disposal and resource utilization of hazardous wastes, and specifically relates to a flue gas treatment method for a copper-containing sludge smelting furnace and a sintering furnace. Background Art

[0002] At present, the recycling and disposal method of copper-containing waste is mainly pyrometallurgical technology, but the flue gas from pyrometallurgical smelting needs to be treated to avoid environmental impact. The equipment of the flue gas treatment system is complex, with high investment cost and high operating cost.

[0003] The Chinese patent with application number 202110445181.9 discloses a flue gas processor of an ice-net type high-temperature alloy smelting furnace. Through the setting of a deheating ice ball net, the filter net and the water cooling channel in the prior art are combined, so that when the flue gas passes through the deheating ice ball net, it can simultaneously intercept, adsorb and cool down the impurities in the flue gas. Moreover, compared with the water cooling outside the smoke exhaust pipe or equipment in the prior art, the contact area between the deheating ice ball net and the flue gas is larger and the distance is closer, thereby significantly improving the cooling effect of the flue gas. At the same time, in conjunction with the effect of the heat-gathering ash-catching string, under the impact of the flue gas, multiple water-seepage ropes can be flying and intertwined with multiple adjacent water-seepage ropes, thereby forming a layer of impurity interception and adsorption barrier with a moist surface under the deheating ice ball net, which has a better effect of cooling and removing impurities from the flue gas.

[0004] It is desirable to provide an improved method for treating flue gas from copper-containing sludge smelting furnaces and sintering furnaces, particularly with regard to reducing the cost of the flue gas treatment system and improving the energy efficiency. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a flue gas treatment method for a copper-containing sludge smelting furnace and a sintering furnace, the purpose of which is to reduce costs and improve energy efficiency.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is: a flue gas treatment method for a copper-containing sludge smelting furnace and a sintering furnace, comprising:

[0007] Flue gas from the sintering furnace flows along a first flue gas flow path and is processed;

[0008] Flue gas from the smelting furnace flows along a second flue gas flow path and is processed;

[0009] Among them, the sintering furnace is connected with the smelting furnace through the batching and brick making system.

[0010] Along the first flue gas flow path, flue gas separation equipment, a first dust filtering device, a thermal storage high-temperature oxidation device, a denitrification system, a desulfurization product dehydration system, a wet electrostatic precipitator and a flue gas dewhitening system are arranged in sequence.

[0011] The flue gas separation equipment is a cyclone separator.

[0012] The first dust filtering device is a bag dust collector.

[0013] Along the second flue gas flow path, dust removal equipment, a surface cooler and a second dust filtering device are arranged in sequence, and the second dust filtering device is connected to the desulfurization product dehydration system.

[0014] The dust removal equipment is a gravity dust collector.

[0015] The second dust filtering device is a bag dust collector.

[0016] The first dust filter device and the second dust filter device are connected to an activated carbon injection system, and the activated carbon injection system adds activated carbon into the first dust filter device and the second dust filter device.

[0017] The first dust filtering device is connected to the batching and brick making system.

[0018] The flue gas treatment method of the copper-containing sludge smelting furnace and the sintering furnace of the present invention can reduce the cost and improve the energy efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] This specification includes the following drawings, which show the following contents:

[0020] Figure 1 It is a flow chart of the flue gas treatment method of the copper-containing sludge smelting furnace and the sintering furnace of the present invention;

[0021] The markings in the figure are: 1. Batching and brick-making system; 2. Smelting furnace; 3. Dust removal equipment; 4. Surface cooler; 5. Second dust filter device; 6. Regenerative high-temperature oxidation equipment; 7. Denitrification system; 8. Desulfurization product dehydration system; 9. Wet electrostatic precipitator; 10. Flue gas desulfurization system; 11. Chimney; 12. Sintering furnace; 13. Flue gas separation equipment; 14. First dust filter device; 15. Granulation equipment. DETAILED DESCRIPTION

[0022] The specific implementation methods of the present invention are further explained in detail below by describing the embodiments with reference to the accompanying drawings, with the aim of helping those skilled in the art to have a more complete, accurate and in-depth understanding of the concept and technical solution of the present invention and facilitating its implementation.

[0023] It should be noted that, in the following embodiments, the “first” and “second” mentioned do not represent an absolute distinction in structure and / or function, nor do they represent a sequential order of execution, but are merely for the convenience of description.

[0024] like Figure 1 As shown, the present invention provides a flue gas treatment method for a copper-containing sludge smelting furnace 2 and a sintering furnace 12, comprising:

[0025] The flue gas from the sintering furnace 12 flows along the first flue gas flow path and is processed;

[0026] The flue gas from the smelting furnace 2 flows along the second flue gas flow path and is processed.

[0027] Specifically, the flue gas treatment method of the copper-containing sludge smelting furnace 2 and the sintering furnace 12 of the present invention uses countercurrent drying and environmentally friendly smelting technology to extract matte from metal-containing waste. Hazardous solid waste is proportionally mixed with other auxiliary materials, and then dried, sintered and smelted in sequence to finally obtain matte as a byproduct, and water-quenched slag as an intermediate byproduct. The water-quenched slag can be treated as general solid waste because the glass content exceeds 85%. While disposing of waste, the loss of heavy metal resources is reduced, and at the same time, the pollution of soil and groundwater and the occupation of a large amount of land that may be caused by ordinary landfill disposal methods are avoided.

[0028] The present invention adopts appropriate and perfect flue gas treatment technology to treat the flue gas of the sintering furnace 12 and the smelting furnace 2 respectively and discharge them in compliance with the standards, thereby reducing pollution to the environment. In particular, the treatment facilities of the regenerative high temperature oxidation equipment 6 + denitrification system 7 are added to the flue gas of the sintering furnace 12, which can effectively remove organic matter, odor, dioxins and nitrogen oxides in the flue gas.

[0029] The flue gas at the outlet of the copper-containing sludge sintering furnace generally contains volatile organic compounds or odors. The traditional treatment process generally uses a secondary combustion chamber, which consumes more fuel to heat the flue gas to above 850°C, and then enters the back-end system after cooling, and the heat is not fully utilized. In the present invention, the regenerative high-temperature oxidation equipment 6 uses an RTO furnace. The temperature in the treatment stage is higher than 850°C. Due to the special internal structure, the heat will be recovered and then heated to the air volume at the inlet of the RTO furnace. The actual temperature of the exhaust flue gas is only about 320-400°C, which reduces the heat loss of the system and thus the fuel consumption.

[0030] In addition, the reaction temperature of SCR is generally above 320°C. If the flue gas temperature entering the SCR is too low, fuel will be needed for heating. The combined process of RTO+SCR is used to control the exhaust temperature of RTO to meet the reaction temperature range of SCR, thus avoiding the fuel required for secondary heating of the flue gas and reducing costs.

[0031] like Figure 1 As shown, along the first flue gas flow path, a flue gas separation device 13, a first dust filter device 14, a thermal storage high-temperature oxidation device 6, a denitrification system 7, a desulfurization product dehydration system 8, a wet electrostatic precipitator 9 and a flue gas dewhitening system 10 are arranged in sequence.

[0032] The flue gas production of a single sintering furnace 12 is 100000m 3 / h, the dust content of the initial flue gas discharged from the sintering furnace 12 is 20g / Nm 3 The maximum temperature of the initial flue gas discharged from the sintering furnace 12 is 180°C, which can reach 300°C instantly, and the moisture content of the initial flue gas discharged from the sintering furnace 12 is 50%. The flue gas discharged from the sintering furnace 12 flows along the first flue gas flow path, and the flue gas discharged from the sintering furnace 12 passes through the flue gas separation device 13, the first dust filter device 14, the regenerative high-temperature oxidation device 6, the denitration system 7, the desulfurization product dehydration system 8, the wet electrostatic precipitator 9 and the flue gas deoxidation system 10 in sequence, and is finally discharged from the chimney.

[0033] like Figure 1 As shown, the flue gas separation device 13 is connected to the sintering furnace 12 through a flue. Preferably, the flue gas separation device 13 is a cyclone separator. A cyclone separator is a device widely used for separation of gas-solid systems. Its working principle is mainly based on the rotational motion caused by the tangential introduction of airflow, so that solid particles with large inertial centrifugal force are thrown to the outer wall to separate. The cyclone separator has the advantages of high separation efficiency and low cost.

[0034] Preferably, the first dust filter device 14 is a bag filter. The bag filter is a dry dust filter. The filter bag is made of textile filter cloth or non-textile felt, and the dust-containing gas is filtered by the filtering effect of the fiber fabric. When the dust-containing gas enters the bag filter, the dust with large particles and high specific gravity settles down due to gravity and falls into the ash hopper. When the gas containing finer dust passes through the filter material, the dust is retained, so that the gas is purified. The dust collection efficiency of the bag filter can reach more than 99%, and it is easy to maintain and the maintenance cost is relatively low.

[0035] As a preferred example, Figure 1 As shown, the first dust filter 14 is connected to the flue gas separation device 13 through a flue, and the flue is connected to an activated carbon injection system. The activated carbon injection system adds activated carbon into the flue, and the activated carbon removes dioxins in the flue. After the activated carbon adsorbs the dioxins in the flue gas, it is collected by a bag dust collector to achieve the purpose of removing dioxins.

[0036] like Figure 1As shown, the regenerative high temperature oxidation equipment 6 is connected to the first dust filter device 14 through a flue. The temperature in the oxidation chamber of the regenerative high temperature oxidation equipment 6 is set to 850-1100°C, and the residence time in the oxidation chamber is extended to >2s, so that CO and VOCs in the flue gas are oxidized and decomposed into harmless CO2 and H2O; the heat after oxidation is "stored" by the heat storage body in the furnace and used to preheat the newly entering organic waste gas, thereby saving the fuel consumption required for heating and reducing operating costs.

[0037] like Figure 1 As shown, the denitration system 7 is connected to the thermal storage high temperature oxidation device 6 through the flue. The denitration system 7 uses a catalyst to mix the NOx in the flue gas with a reducing agent at a certain temperature to generate nitrogen and water, thereby reducing the emission of NOx and reducing the pollution of the flue gas to the environment. The active temperature range of the high-temperature catalyst in the denitration system 7 is set to 320-400°C. SCR is divided into low temperature, medium temperature, and high temperature forms. The higher the temperature, the lower the cost of the catalyst and the higher the activity. When the temperature is high, the acidic gas in the flue gas can also be prevented from corroding the equipment. Therefore, the present invention uses a medium and high temperature catalyst.

[0038] like Figure 1 As shown, the desulfurization product dehydration system 8 is connected to the denitrification system 7 through the flue, and the desulfurization product dehydration system 8 includes a primary dehydration system, a vacuum belt filter system, a wastewater discharge system and a desulfurization slag storage system. The limestone-gypsum wet flue gas desulfurization process mainly uses cheap and readily available limestone as a desulfurization absorbent. Limestone powder is mixed and stirred with water to form an absorbent slurry. In the absorption tower, the stone absorption slurry is contacted and mixed with the flue gas. The sulfur dioxide in the flue gas is absorbed and reacts chemically with the calcium hydroxide in the slurry and the oxidizing air blown in. The final product is gypsum. The desulfurized flue gas passes through the demister to remove the droplets and then enters the chimney for discharge. The equipment is suitable for flue gas desulfurization of various types of industrial furnaces and has high desulfurization efficiency. Limestone-gypsum wet desulfurization is the most mature and widely used desulfurization process in the world.

[0039] like Figure 1 As shown, the wet electrostatic precipitator 9 is connected to the desulfurization product dehydration system 8 through the flue. The wet electrostatic precipitator 9 is a dust removal device 3 used to treat trace dust and microparticles, and is mainly used to remove dust, acid mist, water droplets, aerosols, odors, and other harmful substances in wet gases.

[0040] like Figure 1 As shown, the flue gas whitening system 10 is connected to the wet electrostatic precipitator 9 through the flue. The flue gas whitening system 10 is mainly used to reduce the water content in the flue gas after desulfurization and eliminate the white water vapor generated by the condensation of saturated water vapor in the flue gas after discharge. The main equipment for flue gas whitening includes a whitening heat exchanger and a whitening fan. When the ambient temperature is 10°C and the ambient humidity is not greater than 80%, no white smoke is seen in the whitening system.

[0041] like Figure 1 As shown, along the second flue gas flow path, dust removal equipment 3, surface cooler 4 and second dust filtering device 5 are arranged in sequence, and the second dust filtering device 5 is connected to the desulfurization product dehydration system 8.

[0042] The amount of flue gas produced by the melting furnace is 50000m 3 / h, the dust content of the initial flue gas discharged from the melting furnace is 15g / Nm 3 The initial flue gas temperature discharged from the melting furnace is 350-500°C, and the initial flue gas moisture content discharged from the melting furnace is 5%.

[0043] The flue gas discharged from the melting furnace flows along the second flue gas flow path. The flue gas discharged from the melting furnace passes through the dust removal equipment 3, the surface cooler 4, the second dust filter 5, the desulfurization product dehydration system 8, the wet electrostatic precipitator 9 and the flue gas decolorization system 10 in turn, and is finally discharged from the chimney. The first flue gas flow path and the second flue gas flow path share the desulfurization product dehydration system 8, the wet electrostatic precipitator 9 and the flue gas decolorization system 10. The flue gas of the melting furnace mainly contains dust and SO2, so the flue gas treatment facilities are mainly for dust removal and cooling in the front section, and the back end is used for desulfurization. In addition, after the flue gas undergoes wet desulfurization, there will be more water vapor in the flue gas, causing the phenomenon of white smoke in the exhaust flue gas. Therefore, a wet electrostatic precipitator is configured. While further removing dust, part of the water mist can be removed, and then enter the flue gas decolorization system, so that the exhaust flue gas meets the standard while preventing the phenomenon of white smoke (white smoke is a phenomenon that occurs after the water vapor in the flue gas condenses. It is not a pollutant and will not pollute the environment, but only affects the perception.)

[0044] like Figure 1 As shown, the dust removal device 3 is connected to the smelting furnace 2 through a flue. Preferably, the dust removal device 3 is a gravity dust collector. A gravity dust collector is a device that uses the gravity of the dust itself to settle and separate dust particles from the smoke. Its working principle is mainly to suddenly reduce the air flow rate and change the flow direction, so that larger particles of dust are separated from the gas under the action of gravity and inertia, and settle to the bottom of the dust collector cone, thereby achieving the purpose of dust removal. The gravity dust collector has the advantages of high dust removal efficiency, simple structure and convenient maintenance.

[0045] like Figure 1As shown, the surface cooler 4 is connected to the dust removal device 3 through a flue, and the flue gas of the smelting furnace 2 enters the surface cooler 4 after passing through the dust removal device 3. The inlet flue gas temperature of the surface cooler 4 is 350-500°C, and the flue gas temperature after being treated by the surface cooler 4 is reduced to 180-200°C. An ash hopper and an ash conveying device are arranged under the surface cooler 4. By reducing the flue gas temperature, the surface cooler 4 helps to reduce the content of harmful substances in the flue gas, and these substances are condensed and collected during the cooling process, thereby reducing pollution to the environment.

[0046] As a preferred example, Figure 1 As shown, the second dust filter device 5 is connected to the surface cooler 4 through a flue, and the flue is connected to an activated carbon injection system. The activated carbon injection system adds activated carbon into the flue, and the dioxins in the flue are removed by the activated carbon. After the activated carbon adsorbs the dioxins in the flue, they are collected by the second dust filter device 5, thereby achieving the purpose of removing dioxins.

[0047] like Figure 1 As shown, the sintering furnace 12 is connected to the smelting furnace 2 through the batching and brick-making system 1, and the batching and brick-making system 1 is used to make solid waste bricks. The batching and brick-making system 1 mainly includes a material pool, a batching bin, a screening hopper, a quantitative feeder and brick-making equipment. The working process of the batching and brick-making system 1 is as follows: the solid waste and auxiliary materials that have been classified and stored in the material pool are transported to the batching bin for mixing by a driving grab bucket, and the quantitative feeder is used for metering. The precisely measured solid waste and auxiliary materials are transported by a belt conveyor to the brick-making equipment in the mixing brick-making workshop. The brick-making equipment in this workshop completes the disintegration, mixing and brick-making, and makes the solid waste and auxiliary materials into solid waste bricks. The role of the auxiliary materials is mainly to facilitate the forming and bonding of bricks and to increase the glass phase in the water-quenched slag after the rear-end smelting.

[0048] Copper-containing waste containing copper metal is a hazardous waste. Copper-containing waste, carbon and limestone powder are mixed in a certain ratio to form a first mixture. The addition of limestone powder can absorb the moisture in the waste, thereby reducing the moisture content of the first mixture without drying the first mixture. Figure 1 As shown, the granulation equipment 15 is connected to the sintering furnace 12, and the first mixed material is added into the granulation equipment 15 for granulation and forming to obtain a spherical mixture with a diameter of 3mm to 5mm or more, and the spherical mixture is transported to the sintering furnace 12 for sintering. After the sintering is completed, a sintered material block is formed, which is a relatively dense block.

[0049] like Figure 1As shown, the sintering furnace 12 is connected to the batching and brick-making system 1, and the honeycomb sintered material blocks enter the batching and brick-making system 1 to make solid waste bricks. The sintered material blocks are broken up and transported to the screening hopper. The sintered fine material with a diameter of less than 30 mm in the screening hopper enters the brick-making equipment, and cement is added to the brick-making equipment. The cement and the sintered fine material are mixed to make solid waste bricks, and the solid waste bricks contain copper; the sintered coarse material with a diameter of not less than 30 mm in the screening hopper enters the batching bin, and the carbon block, quartz stone, limestone and iron powder are respectively put into the batching bin and mixed with the sintered coarse material to form a second mixture. Finally, the solid waste bricks and the second mixture are added to the smelting furnace 2, and the by-product matte and the intermediate by-product water-quenched slag are obtained after smelting. While disposing of waste, the loss of heavy metal resources is reduced, and at the same time, the pollution of soil and groundwater and the occupation of a large amount of land that may be caused by ordinary landfill disposal methods are avoided.

[0050] As a preferred example, Figure 1 As shown, the first dust filter device 14 is connected to the brick-making equipment of the batching and brick-making system 1. The fly ash generated in the first dust filter device 14 is added to the brick-making equipment, and the fly ash is mixed with cement and sintered fine materials in the brick-making equipment to make solid waste bricks. The fly ash collected by the dust removal system and the powdered sintered materials with fine particles of less than 30 mm that are screened directly enter the smelting furnace, which will affect the effect of the smelting reaction (that is, the contact between the powdered materials and iron powder, limestone, and quartz stone is poor), and a large amount of materials may be directly carried out with the flue gas. Therefore, after this part of the materials is used for brick making, they are mixed with coarse particles of sintered materials in proportion and then smelted, so as to make full use of the powdered materials.

[0051] A mobile distribution trolley is provided on the top of the smelting furnace 2. Solid waste bricks and carbon concentrate are transported to the top of the smelting furnace 2 by the mobile distribution trolley for distribution. The mobile distribution trolley is provided with a motor transmission component, and the boiler operator operates the handle to move the distribution. The feeding part of the smelting furnace 2 is at the top of the furnace, the discharge is at the bottom of the furnace, and the furnace side is blasted. After melting, the matte and slag have different specific gravities. The matte sinks to the bottom of the furnace of the smelting furnace 2, and the slag floats on the upper layer of the furnace of the smelting furnace 2. The matte and slag are discharged through different outlets. The slag flows through the slag chute to the slag scoop machine for water quenching and then enters the slag pit for storage. The matte flows into the linear casting machine for casting to produce matte ingots.

[0052] The above-mentioned flue gas treatment method of the copper-containing sludge smelting furnace 2 and the sintering furnace 12 has the following advantages:

[0053] (1) After hazardous waste is treated, the copper recovery rate can reach more than 90%. In addition, precious metals such as gold and silver can be melted in copper to achieve the purpose of resource recovery;

[0054] (2) After the treatment, the glass content of the water-quenched slag is greater than 85%, which meets the standard requirements and can be sold as a building material resource;

[0055] (3) The flue gas is treated by the above system and meets the emission standards;

[0056] (4) The flue gas from sintering furnace 12 and smelting furnace 2 shall be discharged through the chimney after being treated to meet the standards. The emission limits of particulate matter, sulfur dioxide, nitrogen oxides, dioxins, lead, chromium and cadmium in this part of the flue gas shall refer to the emission limits of atmospheric pollutants in Table 3 of "GB 31574-2015 Pollutant Emission Standard for Recycled Copper, Aluminum, Lead and Zinc Industries". The emission limits of fluoride shall comply with the secondary standards of "Emission Standard of Atmospheric Pollutants for Industrial Furnaces" (GB9078-1996); the emission limits of HCl and Ni shall comply with the secondary standards of "Comprehensive Emission Standard of Atmospheric Pollutants" (GB16297-1996).

[0057] The present invention is described above by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention; or the above concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A method for treating flue gas from a copper-containing sludge smelting furnace and a sintering furnace, characterized in that: include: Flue gas from the sintering furnace flows along a first flue gas flow path and is processed; Flue gas from the smelting furnace flows along a second flue gas flow path and is processed; Among them, the sintering furnace is connected with the smelting furnace through the batching and brick making system.

2. The flue gas treatment method for a copper-containing sludge smelting furnace and a sintering furnace according to claim 1, characterized in that: Along the first flue gas flow path, flue gas separation equipment, a first dust filtering device, a thermal storage high-temperature oxidation device, a denitrification system, a desulfurization product dehydration system, a wet electrostatic precipitator and a flue gas dewhitening system are arranged in sequence.

3. The flue gas treatment method for a copper-containing sludge smelting furnace and a sintering furnace according to claim 2, characterized in that: The flue gas separation equipment is a cyclone separator.

4. The flue gas treatment method for a copper-containing sludge smelting furnace and a sintering furnace according to claim 2, characterized in that: The first dust filtering device is a bag dust collector.

5. The flue gas treatment method for a copper-containing sludge smelting furnace and a sintering furnace according to any one of claims 2 to 4, characterized in that: Along the second flue gas flow path, dust removal equipment, a surface cooler and a second dust filtering device are arranged in sequence, and the second dust filtering device is connected to the desulfurization product dehydration system.

6. The flue gas treatment method for a copper-containing sludge smelting furnace and a sintering furnace according to claim 5, characterized in that: The dust removal equipment is a gravity dust collector.

7. The flue gas treatment method for a copper-containing sludge smelting furnace and a sintering furnace according to claim 5, characterized in that: The second dust filtering device is a bag dust collector.

8. The method for treating flue gas from a copper-containing sludge smelting furnace and a sintering furnace according to claim 5, characterized in that: The first dust filter device and the second dust filter device are connected to an activated carbon injection system, and the activated carbon injection system adds activated carbon into the first dust filter device and the second dust filter device.

9. The flue gas treatment method for a copper-containing sludge smelting furnace and a sintering furnace according to any one of claims 2 to 8, characterized in that: The first dust filtering device is connected to the batching and brick making system.

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