Method for removing CO from lime kiln tail flue gas after denitration and dust removal integration

Abstract

The invention discloses a method for removing CO after denitration and dust removal integration of lime kiln tail flue gas, and belongs to the technical field of CO removal of lime kiln flue gas. The method systematically solves the pain point of collaborative treatment of multiple pollutants in the lime kiln flue gas. According to the economical efficiency, a non-noble metal catalyst and equipment are integrated, and the investment and operation cost is reduced; reliability: ultra-microporous filtration and deep desulfurization guarantee long-acting operation of the catalyst (service life gt; 3 years); the method is environment-friendly, ammonia escape, NOx and CO synchronously reach the standard (actually measured NOx removal rate is larger than or equal to 98.5%, and CO removal rate is larger than or equal to 96.2%), and the ultralow emission requirement is met.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lime kiln flue gas CO removal, and particularly relates to a method for removing CO after removing dust and denitration of lime kiln tail flue gas. BACKGROUND

[0002] With the gradual implementation of the Air Pollution Prevention and Control Law of the People's Republic of China and the Emission Standard of Air Pollutants for Iron and Steel Industry and other series of regulations, the steel enterprises have formed effective control over pollutants such as sulfur dioxide (SO2), nitrogen oxides (NOx), particulate matter (PM) and the like. With the development of high-quality economic mode, the emission control of the above-mentioned pollutants will be more stringent, and at the same time, in order to further improve the air quality, some new types of pollutants such as CO will also become the object of emission reduction. Since 2018, Hebei and Shanxi have issued requirements for the control of carbon monoxide emissions in the steel industry, and the steel industry will control the emission of CO, which will become the focus of air pollution control in the steel industry in the new stage.

[0003] The lime kiln flue gas treatment process mainly uses desulfurization + dust removal + heating denitration + CO reactor, and with the development and upgrading of environmental protection technology, the desulfurization and dust removal process is integrated in the lime kiln flue gas treatment to form a kiln tail flue gas dust removal and denitration integrated process, achieving ultra-low emission of SO2, NOx, particulate matter and other emissions.

[0004] In the prior art, the utility model patent with the application number CN202323369749.7 discloses an energy-saving and environment-friendly lime kiln denitration and dust removal device. The utility model relates to the technical field of lime kiln flue gas treatment, and particularly relates to an energy-saving and environment-friendly lime kiln denitration and dust removal device, which comprises a lime kiln, a waste heat recovery device is connected to the upper end of the lime kiln, a denitration bag-type dust collector is connected to the waste heat recovery device, the denitration bag-type dust collector is desulfurized through a desulfurizing agent injection device, the desulfurizing agent injection device is connected to a hot blast furnace after desulfurization, and ammonia water is sprayed into the hot blast furnace through an ammonia spraying system. The device uses the net flue gas after dust removal to gasify ammonia water, reduces the system power consumption, uses the waste heat recovery system controlled by the valve, can recover more heat when the initial flue gas temperature is sufficient, uses the cyclone device before the denitration and dust removal device to improve the mixing effect of ammonia gas and flue gas and improve the denitration efficiency, uses the denitration and bag-type dust removal integrated device to reduce the process link setting, reduce the land occupation area, and reduce the investment and operation cost.

[0005] In the prior art, an application number CN202011538520.X invention patent discloses a catalyst for removing CO in sintering flue gas and a preparation method thereof. The main content is as follows: the invention provides a catalyst for removing CO in sintering flue gas and a preparation method thereof, which comprises, by weight percentage, 88-92wt% of alumina ball carrier and 8-12wt% of active ingredient; the active ingredient comprises an active component; the active component is composed of CuOx and MnOx; the mass ratio of CuOx and MnOx is (1-2.5):1. On the one hand, the catalyst improves the mechanical strength of the catalyst by using a spherical carrier; on the other hand, by using transition metal oxides as the main active component of the catalyst, the preparation cost is reduced and there is no secondary pollution, and the efficient removal of CO in lime kiln tail flue gas can be realized, which has good industrial application prospect.

[0006] However, the above-mentioned lime kiln tail flue gas CO removal process still has the following technical problems: 1. The desulfurization, dust removal, denitrification and CO removal process devices need to be set respectively, the equipment occupies a large area, the running resistance is large, and the running cost is high; 2. The dust removal technology has low precision, which affects the service life of the denitrification and CO catalyst; 3. The noble metal catalyst is used to remove CO, which has high cost; 4. The SO2 concentration fluctuates greatly, which easily causes poisoning of the CO catalyst, and a CO catalyst protection system needs to be set at the front end; 5. Ammonia escape is high, which shortens the service life of the denitrification and CO catalyst, and the environmental protection is not up to standard. SUMMARY

[0007] Technical problems of the prior art: (1) Equipment is redundant: desulfurization, dust removal, denitrification and CO removal devices need to be set independently, which occupies a large area, has high resistance and high running cost.

[0008] (2) Low dust removal precision: dust residue leads to blockage and failure of the subsequent catalyst.

[0009] (3) High cost: CO removal relies on noble metal catalysts (such as platinum and palladium).

[0010] (4) Catalyst poisoning: SO2 concentration fluctuation causes deactivation of the CO catalyst, and an additional protection system is needed.

[0011] (5) Serious ammonia escape: escaped ammonia causes shortening of the service life of the catalyst and secondary pollution.

[0012] Therefore, the present application provides a method for denitrification and dust removal integrated post-CO removal of lime kiln tail flue gas to achieve the above-mentioned purpose.

[0013] Specifically, the purpose of the present application can be achieved by the following technical solutions: A method for removing CO after desulfurization and dedusting of lime kiln tail gas, comprising the following steps: S1, the lime kiln tail gas is heated and warmed to 220-280 DEG C by GGH heat exchanger, and then warmed to 280-350 DEG C by hot blast stove heating system, obtaining medium temperature flue gas; S2, the desulfurizer baking soda and ammonia are sprayed into the medium temperature flue gas in turn, obtaining pretreated flue gas; S3, the pretreated flue gas enters the denitration CO removal and dedusting device, and passes through the denitration dedusting filter bag and CO catalyst in turn, obtaining treated flue gas; S4, the treated flue gas is returned to the GGH heat exchanger for heat exchange, and then discharged by the chimney after being pressurized by the booster fan.

[0014] Further, the denitration dedusting filter bag in S3 is a composite structure of expanded polytetrafluoroethylene membrane and catalyst polytetrafluoroethylene composite felt layer.

[0015] Further, the denitration dedusting filter bag in S3 comprises the following mass parts of raw materials: Polytetrafluoroethylene fiber felt 100 parts; Catalyst slurry 30 parts; Expanded polytetrafluoroethylene membrane 5 parts.

[0016] Further, the grammage of the polytetrafluoroethylene fiber felt is 800 g / m2.

[0017] Further, the pore size of the expanded polytetrafluoroethylene membrane is 0.03 μm.

[0018] Further, the denitration dedusting filter bag is prepared by the following steps: The raw materials are weighed according to the mass parts, the catalyst slurry is coated on both sides of the polytetrafluoroethylene fiber felt, the expanded polytetrafluoroethylene membrane is covered after coating, and then hot pressing is performed, and finally the denitration dedusting filter bag is obtained.

[0019] Further, the temperature of the hot pressing is 190 DEG C, the pressure is 3 MPa, and the time is 10 min.

[0020] Further, the catalyst slurry comprises the following mass parts of raw materials: Manganese dioxide 55 parts; Cerium dioxide 15 parts; Tungsten trioxide 10 parts; Oxidized graphene 5 parts; Silane coupling agent KH-550 2 parts; PTFE emulsion 23 parts.

[0021] Further, the graphene oxide has a flake diameter of 10 μm.

[0022] Further, the PTFE emulsion has a solid content of 60%.

[0023] Further, the catalyst slurry is prepared by the following steps: The raw materials are weighed according to the mass fraction, the manganese dioxide, cerium dioxide and tungsten trioxide are added into a ball mill tank, ball milling is performed for 2 h, after completion, catalyst powder is obtained, then the graphene oxide, silane coupling agent KH-550 and PTFE emulsion are added into the catalyst powder, ball milling is performed for 2 h, after completion, the catalyst slurry is obtained.

[0024] Further, the rotation speed of the ball milling is 300 rpm.

[0025] Further, the CO catalyst in S3 comprises the following mass fraction of raw materials: 100 parts of cordierite honeycomb ceramics; 40 parts of active coating slurry.

[0026] Further, the cordierite honeycomb ceramics have a size of 150 mm in diameter x 100 mm in length.

[0027] Further, the CO catalyst is prepared by the following steps: The raw materials are weighed according to the mass fraction, the cordierite honeycomb ceramics are immersed in the active coating slurry for 10 min, after taking out, compressed air is used for blowing, then the cordierite honeycomb ceramics are placed in a drying oven at 110 ℃ for 3 h, and then placed in a muffle furnace at 600 ℃ for 5 h, after completion, the CO catalyst is obtained after natural cooling to room temperature.

[0028] Further, the active coating slurry comprises the following mass fraction of raw materials: 40 parts of copper oxide; 30 parts of manganese dioxide; 25 parts of ceria-zirconia oxide; 5 parts of pseudo-boehmite.

[0029] Further, the active coating slurry is prepared by the following steps: The raw materials are weighed according to the mass fraction, the copper oxide, manganese dioxide and ceria-zirconia oxide are mixed and ball milled to a particle size D90 < 10 μm, after completion of the ball milling, a mixture is obtained, then the pseudo-boehmite and deionized water are added into the mixture to prepare a 50 wt% active coating slurry.

[0030] Further, the ammonia source in S2 is a ammonia spraying system, and the ammonia spraying system comprises an ammonia water gasification furnace, an ammonia water conveying pump, an ammonia water tank, an ammonia unloading pump and a gasification fan.

[0031] The core innovation and principle of the application are as follows: 1. Integrated process design: (1) Technical solution: The present application integrates denitration, dust removal and CO removal in a single device (denitration CO removal and dust removal device), and the flue gas is sequentially purified by denitration dust removal filter bag and CO catalyst.

[0032] (2) Principle: A. Front-end pretreatment: The flue gas is heated by GGH heat exchanger (220-280℃) and then heated to 280-350℃ by hot blast stove (to meet the temperature of medium-temperature denitration).

[0033] Baking soda dry desulfurization: First spray baking soda (200g / Nm3) to remove SO2 efficiently, reduce the risk of subsequent catalyst sulfur poisoning.

[0034] Precise ammonia injection: Ammonia and flue gas are fully mixed to provide reducing agent for denitration.

[0035] B. Purification by integrated device: Denitration dust removal filter bag: The surface layer of expanded polytetrafluoroethylene membrane (0.03μm pore size) intercepts ultrafine dust (dust removal rate close to 100%), and the inner layer of catalyst felt layer (MnO2-CeO2-WO3 / PTFE) catalyzes the reaction of NOx and NH3 to generate N2 and H2O (denitration rate ≥98.5%).

[0036] CO catalyst: Cordierite honeycomb ceramic as carrier, loaded with CuO-MnO2-CeZrOx active coating, catalytic oxidation of CO to CO2 in clean flue gas after dust removal and denitration (removal rate ≥96.2%).

[0037] 2. Key material innovation: (1) Denitration dust removal filter bag: Composite structure: expanded PTFE membrane (ultrafine pore filtration) + catalyst / PTFE fiber felt (catalytic denitration).

[0038] Catalyst formula: MnO2 (main catalyst) + CeO2 (oxygen storage) + WO3 (enhanced acidity) + graphene oxide (enhanced electronic conductivity) + KH-550 (enhanced bonding strength).

[0039] Effect: 0.03μm ultra-high precision dust removal, protecting the subsequent CO catalyst from the source; low ammonia escape (≤1.5ppm).

[0040] (2) CO catalyst: Non-noble metal system: CuO-MnO2-CeZrOx combination, using transition metal to synergistically catalyze CO oxidation, with a cost of only 1 / 5-1 / 10 of noble metal.

[0041] Anti-poisoning design: CeZrOx improves oxygen storage capacity, and pseudo-boehmite enhances coating stability; stable structure is formed after 600℃ calcination.

[0042] 3. Thermal energy cycle optimization: GGH heat exchanger energy recovery: CO removal reaction releases heat, which raises the temperature of the net flue gas, returns to the GGH to preheat the inlet flue gas, and reduces the hot blast furnace gas consumption by more than 20%.

[0043] Energy saving of ammonia injection system: ammonia water is gasified by high-temperature flue gas after purification, reducing system energy consumption.

[0044] Compared with the prior art, the beneficial effects of the present application are: (1) Equipment intensification: desulfurization (soda injection), denitrification, dust removal, and CO removal are integrated in a single device, reducing equipment footprint by more than 40% and investment cost by 30%, with a system pressure drop of only 850-900 Pa.

[0045] (2) Long-term anti-poisoning mechanism: soda pre-desulfurization (SO2 removal rate > 95%) + 0.03 μm ultrafiltration dust removal, making the dust concentration < 5 mg / Nm3, blocking the catalyst from plugging and sulfur poisoning from the source, and prolonging the CO catalyst life by more than 2 times.

[0046] (3) Low-cost and high-efficiency CO removal: transition metal catalyst (CuO-MnO2-CeZrOx) replaces noble metal, reducing cost by 80%, with high activity at low temperature (280-350℃), and CO removal rate ≥ 96.2%.

[0047] (4) Precise control of ammonia escape: the catalytic layer in the filter bag reacts fully with NH3, with escape ammonia ≤ 1.5 ppm, far exceeding the national standard (< 3 ppm), avoiding secondary pollution and catalyst deactivation.

[0048] (5) Energy recycling: CO removal releases heat (CO→CO2, ΔH=-283kJ / mol), which raises the temperature of the net flue gas, and the heat is recovered by GGH, reducing the coal gas consumption of the heat supplement system by 20%-30%.

[0049] Summary: Through the process chain of "soda pre-desulfurization → ultrafiltration dust removal / denitrification → transition metal CO removal", the present application systematically solves the pain points of multi-pollutant simultaneous control of lime kiln flue gas: Economical: non-noble metal catalyst + equipment integration, reducing investment and operating costs.

[0050] Reliability: ultra-microporous filtration + deep desulfurization, ensuring long-term operation of the catalyst (life > 3 years).

[0051] Environmental protection: ammonia escape, NOx, and CO meet the standards simultaneously (measured NOx removal rate ≥ 98.5%, CO removal rate ≥ 96.2%), meeting the requirements of ultra-low emission. Attached Figure Description

[0052] The present invention will now be further described with reference to the accompanying drawings.

[0053] Figure 1 This is a schematic diagram of the integrated denitrification and dust removal device for lime kiln tail flue gas after the present invention; Figure 2 yes Figure 1 Sectional view of AA; Figure 3 yes Figure 1 BB section view.

[0054] In the diagram: 1. Lime kiln; 2. GGH heat exchanger; 3. Heating furnace; 4. Combustion fan; 5. Gasification furnace; 6. Ammonia water transfer pump; 7. Ammonia water tank; 8. Ammonia unloading pump; 9. Gasification fan; 10. Denitrification, CO removal and dust removal device; 11. Booster fan; 12. Chimney; 1001. CO catalyst; 1002. Denitrification and dust removal filter bag. Detailed Implementation

[0055] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Furthermore, unless otherwise specified, the raw materials, reagents, or devices used in the following embodiments can be obtained from conventional commercial channels or by existing known methods.

[0056] like Figures 1-3 As shown, the integrated denitrification and dust removal device for lime kiln tail flue gas of the present invention mainly consists of a lime kiln 1, a GGH heat exchanger 2, a heating furnace 3, a combustion fan 4, a gasification furnace 5, an ammonia water transfer pump 6, an ammonia water tank 7, an ammonia unloading pump 8, a gasification fan 9, a denitrification and deCO dust removal device 10, a booster fan 11, and a chimney 12. The denitrification and deCO dust removal device 10 consists of a CO catalyst 1001 and a denitrification and dust removal filter bag 1002.

[0057] The process flow is as follows: the flue gas from the lime kiln 1 kiln tail flue (flue gas temperature is 180-250 DEG C) enters the GGH heat exchanger 2 to heat and rise (temperature rises to 220-280 DEG C) and is heated to the temperature required by the denitration catalyst (the working temperature of the medium-temperature denitration catalyst is 280-350 DEG C) by the hot blast stove heat supplement system, then passes through the desulfurizer (baking soda, particle size 20 μm, dosage 200 g / Nm3) injection point and the ammonia injection point of the ammonia injection system, and then enters the denitration and CO removal device 10, through which the process of CO, nitrogen oxides, sulfur oxides and dust ultra-low emission is realized, and the flue gas treated by the denitration and CO removal device 10 is returned to the GGH heat exchanger 2 for heat exchange (the temperature of the flue gas treated by the denitration and CO removal device 10 is higher than that of the flue gas at the outlet of the lime kiln 1 kiln tail flue, and the heat exchange can reduce the coal gas consumption of the hot blast stove heat supplement system), and the flue gas after heat exchange is pressurized by the booster fan 11 and discharged through the chimney 12, completing the overall process flow. The above process is detected, and the detection process and results are as follows: (1) Denitration / CO removal efficiency: the NOx and CO concentrations of the flue gas at the outlet of the lime kiln 1 kiln tail flue and the chimney 12 are detected by the flue gas analyzer (Testo 350), and the NOx removal rate and CO removal rate are calculated. The detection shows that the NOx removal rate of the present application is ≥98.5%, and the CO removal rate is ≥96.2%; (2) System pressure drop: the pressure loss before and after the denitration and CO removal device 10 is measured by using a differential pressure gauge. The detection shows that the pressure drop of the present application is 850-900 Pa; (3) Ammonia escape: the ammonia escape content in the flue gas discharged from the chimney 12 is detected by using the indophenol blue spectrophotometric method (HJ 533-2009). The detection shows that the ammonia escape of the present application is ≤1.5 ppm.

[0058] The hot blast stove heat supplement system is composed of a heating furnace 3 and a combustion air fan 4. The fuel of the heating furnace 3 is the blast furnace gas in the steel plant area, and the blast furnace gas introduced here is the main source of sulfur oxides in the system.

[0059] The ammonia injection system is composed of an ammonia water gasifier 5, an ammonia water delivery pump 6, an ammonia water tank 7, an ammonia unloading pump 8 and a gasification fan 9. The gasification fan 9 introduces the flue gas purified by the denitration and CO removal device 10, effectively utilizes the temperature of the purified flue gas, and realizes energy saving and emission reduction.

[0060] The denitration and dust removal device 10 is designed in an integrated manner with the denitration and dust removal filter bag 1002, and the filtering precision of the denitration and dust removal filter bag 1002 is 0.03 µm. The denitration and dust removal filter bag 1002 is a composite structure of an expanded polytetrafluoroethylene membrane and a catalyst polytetrafluoroethylene composite felt layer. When the flue gas enters the denitration and dust removal device 10, the flue gas first contacts the expanded polytetrafluoroethylene membrane on the surface of the denitration and dust removal filter bag 1002, so that the particulate matters in the flue gas are filtered and removed, and the removal efficiency is close to 100%. The flue gas that has passed through the expanded polytetrafluoroethylene membrane contacts the catalyst polytetrafluoroethylene composite felt layer. At this time, the NOx in the flue gas reacts with the catalyst in the catalyst polytetrafluoroethylene composite felt layer to generate N2 and H2O. After the flue gas passes through the catalyst polytetrafluoroethylene composite felt layer, the concentration of NOx in the flue gas is reduced to below the limit value of the emission standard.

[0061] Specifically, the denitration and dust removal filter bag 1002 is prepared by the following steps: Raw materials (mass parts): polytetrafluoroethylene fiber felt (gram weight 800 g / m2, Jieqi (Hangzhou) Filter Technology) 100 parts; catalyst slurry (self-made) 30 parts; expanded polytetrafluoroethylene membrane (pore size 0.03 µm, Ningbo Dengyue New Material Technology) 5 parts.

[0062] Preparation steps: the above raw materials are weighed according to the mass parts, and then the catalyst slurry is uniformly coated on both sides of the surface of the polytetrafluoroethylene fiber felt (coating amount is about 250 g / m2). After coating, the expanded polytetrafluoroethylene membrane is covered. After completion, hot pressing is performed (temperature 190 ℃, pressure 3 MPa, time 10 min). After completion, the denitration and dust removal filter bag 1002 is obtained.

[0063] The formula of the catalyst slurry (mass parts) is as follows: manganese dioxide (98.8%, National Pharmaceutical Reagent) 55 parts; cerium dioxide (99.9%, National Pharmaceutical Reagent) 15 parts; tungsten trioxide (99.0%, National Pharmaceutical Reagent) 10 parts; graphene oxide (flake diameter 10 µm, enhanced electron conduction, Xianfeng Nanometer) 5 parts; silane coupling agent KH-550 (improve adhesion, Nanjing Shuguang Chemical Industry) 2 parts; PTFE emulsion (solid content 60%, Guangzhou Songbai Chemical Industry) 23 parts.

[0064] Preparation steps: the above raw materials are weighed according to the mass parts, and then the manganese dioxide, cerium dioxide and tungsten trioxide are added to a ball mill tank. Ball milling is performed for 2 h (rotational speed 300 rpm, zirconium oxide ball medium). After completion, catalyst powder is obtained. Then, the graphene oxide, silane coupling agent and PTFE emulsion are added to the catalyst powder, and ball milling is performed for 2 h (rotational speed 300 rpm). After completion, the catalyst slurry is obtained.

[0065] The CO catalyst 1001 in the denitration and CO dust removal device 10 is a transition metal oxide CO catalyst. The transition metal oxide has oxygen storage and oxygen supply capacity, and can enhance catalytic oxidation in a wide temperature range. The rare earth doping improves the resistance to sulfur and alkali poisoning, so that the catalyst has the characteristics of low temperature, water resistance, sulfur resistance and dust resistance, and is suitable for high humidity, dust and sulfur conditions of steel sintering flue gas.

[0066] Specifically, the CO catalyst 1001 is prepared by the following steps: Raw materials (mass parts): cordierite honeycomb ceramics (diameter 150 mm x length 100 mm, Suzhou Guolongtai Environmental Protection) 100 parts; active coating slurry (self-made) 40 parts.

[0067] Preparation steps: the above raw materials are weighed according to the mass parts, the cordierite honeycomb ceramics are immersed in the active coating slurry for 10 min, and then taken out and blown with compressed air (pressure 0.4 MPa), and then placed in a drying oven at 110°C for 3 h, and then placed in a muffle furnace at 600°C for 5 h, and then naturally cooled to room temperature, to obtain the CO catalyst 1001.

[0068] The formula of the active coating slurry (mass parts) is: copper oxide (National Reagent) 40 parts; manganese dioxide (98.8%, National Reagent) 30 parts; cerium-zirconium oxide (99.0%, Aladdin Reagent) 25 parts; pseudo-boehmite (Yangzhou Zhongtianli New Material) 5 parts.

[0069] Preparation steps: the above raw materials are weighed according to the mass parts, the cordierite honeycomb ceramics are immersed in the active coating slurry for 10 min, and then taken out and blown with compressed air (pressure 0.4 MPa), and then placed in a drying oven at 110°C for 3 h, and then placed in a muffle furnace at 600°C for 5 h, and then naturally cooled to room temperature, to obtain the CO catalyst 1001.

[0070] It should be noted that in this document, terms such as "comprising", "including", or any other variant thereof are intended to cover non-exclusive inclusion, so that processes, methods, articles or devices including a series of elements not only include those elements, but also include other elements not explicitly listed, or still include elements inherent to such processes, methods, articles or devices.

[0071] Although embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A method for integrated denitration and dust removal of lime kiln tail gas and post-removal of CO, characterized in that, It comprises the following steps: S1, the lime kiln (1) kiln tail flue gas is heated to 220~280℃ by GGH heat exchanger (2), and then heated to 280~350℃ by hot blast stove heating system, to obtain medium temperature flue gas; S2, the small soda and ammonia gas are sprayed into the medium temperature flue gas in turn to obtain pretreated flue gas; S3, the pretreated flue gas enters the denitration and dust removal device (10), passes through the denitration and dust removal filter bag (1002) and the CO catalyst (1001) in turn, and obtains the treated flue gas; S4, the treated flue gas is returned to the GGH heat exchanger (2) for heat exchange, and then discharged by the chimney (12) after being pressurized by the booster fan (11); The denitration and dust removal filter bag (1002) in S3 is a composite structure of expanded polytetrafluoroethylene membrane and catalyst polytetrafluoroethylene felt layer.

2. The method according to claim 1, characterized in that, The denitration and dust removal filter bag (1002) in S3 comprises the following mass parts of raw materials: Polytetrafluoroethylene fiber felt 100 parts; Catalyst slurry 30 parts; Expanded polytetrafluoroethylene membrane 5 parts; The polytetrafluoroethylene fiber mat has a grammage of 800 g / m 2 ; The pore size of the expanded polytetrafluoroethylene membrane is 0.03μm.

3. The method according to claim 2, characterized in that, The denitration and dust removal filter bag (1002) is prepared by the following steps: According to the mass parts of the raw materials, the catalyst slurry is coated on both sides of the polytetrafluoroethylene fiber felt, and then the expanded polytetrafluoroethylene membrane is covered. After completion, hot pressing is performed, and after completion, the denitration and dust removal filter bag (1002) is obtained; The temperature of the hot pressing is 190℃, the pressure is 3MPa, and the time is 10min.

4. The method according to claim 2, characterized in that, The catalyst slurry comprises the following mass parts of raw materials: Manganese dioxide 55 parts; Cerium dioxide 15 parts; Tungsten trioxide 10 parts; Oxidized graphene 5 parts; Silane coupling agent KH-550 2 parts; PTFE emulsion 23 parts; The oxidized graphene has a sheet diameter of 10μm; The solid content of the PTFE emulsion is 60%.

5. The method according to claim 4, characterized in that, The catalyst slurry is prepared by the following steps: According to the mass parts of the raw materials, the manganese dioxide, cerium dioxide and tungsten trioxide are added to the ball mill tank, and ball milling is performed for 2h. After completion, the catalyst powder is obtained. Then the oxidized graphene, silane coupling agent KH-550 and PTFE emulsion are added to the catalyst powder, and ball milling is performed for 2h. After completion, the catalyst slurry is obtained; The rotating speed of the ball milling is 300rpm.

6. The method according to claim 1, characterized in that, The CO catalyst (1001) in S3 comprises the following mass parts of raw materials: Cordierite honeycomb ceramic 100 parts; Active coating slurry 40 parts; The size of the cordierite honeycomb ceramic is 150mm in diameter and 100mm in length.

7. The method according to claim 6, characterized in that, The CO catalyst (1001) is prepared by the following steps: According to the mass parts of the raw materials, the cordierite honeycomb ceramic is immersed in the active coating slurry for 10min, and then taken out and blown with compressed air. Then it is placed in a drying oven at 110℃ for 3h, and then placed in a muffle furnace at 600℃ for 5h. After completion, it is naturally cooled to room temperature to obtain the CO catalyst (1001).

8. The method according to claim 6, characterized in that, The active coating slurry comprises the following mass parts of raw materials: Copper oxide 40 parts; Manganese dioxide 30 parts; Cerium zirconium oxide 25 parts; Pseudo-boehmite 5 parts.

9. The method according to claim 8, characterized in that, The active coating slurry is prepared by the following steps: The raw materials are weighed according to mass parts, the copper oxide, manganese dioxide and cerium zirconium oxide are mixed and ball milled to a particle size D90<10 mu m, and after ball milling, a mixture is obtained, then pseudo-boehmite and deionized water are added to the mixture to prepare a 50wt% active coating slurry.

10. The method according to claim 1, characterized in that, The ammonia source in S2 is an ammonia spraying system, which comprises an ammonia water gasification furnace (5), an ammonia water conveying pump (6), an ammonia water tank (7), an ammonia unloading pump (8) and a gasification fan (9).

Images