A catalyst for eliminating carbon monoxide in flue gas and a flue gas treatment process
By employing steps such as carbon monoxide incineration, SNCR denitrification, waste heat recovery, quench tower cooling, neutralization reaction tower desulfurization, and alkali spray tower acid removal, combined with copper-manganese-tin catalyst and urea reducing agent, the problem of carbon monoxide removal in flue gas from small coal-fired power plants has been solved, achieving efficient and low-cost flue gas treatment and improving environmental management and ecological environment quality.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HENGSHUI JINGZHEN ENVIRONMENTAL TECH CO LTD
- Filing Date
- 2023-06-27
- Publication Date
- 2026-07-07
AI Technical Summary
Existing flue gas treatment technologies face challenges in removing carbon monoxide in small coal-fired power plants. Furthermore, traditional methods such as limestone-gypsum desulfurization and selective catalytic oxidation consume large amounts of water, have high operating costs, and cannot effectively remove nitrogen oxides.
A flue gas treatment process is adopted, which includes steps such as carbon monoxide incineration, SNCR denitrification, waste heat recovery, quench tower cooling, neutralization reaction tower desulfurization, dust removal by dust collector and acid removal by alkaline spray tower. Copper, manganese and tin oxide catalysts and urea reducing agent are used, combined with activated quicklime and bag filter to achieve efficient removal of carbon monoxide.
This technology reduces equipment footprint and construction costs, simplifies the construction process, lowers the difficulty of modification and operating costs, achieves stable and compliant emissions of flue gas, improves the standardization of environmental management and energy-saving effects, and improves the ecological environment.
Smart Images
Figure CN116857660B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of industrial flue gas treatment, specifically to a catalyst and flue gas treatment process for eliminating carbon monoxide in flue gas. Background Technology
[0002] Flue gas is the process of recycling and purifying it to meet emission standards. The large amounts of flue gas emitted during non-ferrous metal smelting often contain gaseous pollutants such as sulfur dioxide, fluorides, chlorine, and mercury, which pollute the atmosphere and disrupt the ecological balance. These gaseous pollutants must be immobilized and converted into beneficial products. While single-pollutant control processes such as selective catalytic oxidation (SCR), wet flue gas desulfurization (WFGD), and activated carbon injection (ACI) have high removal efficiency for sulfur dioxide, nitrogen oxides, and mercury, their drawbacks include large land area requirements, complex processes, and high operating costs. Larger coal-fired power plants currently mainly use limestone-gypsum desulfurization and selective catalytic oxidation technologies, which can achieve certain denitrification and mercury removal effects. However, for small coal-fired power plants, the above two methods have significant drawbacks such as high water consumption and high operating costs. For example, patent CN201210368742.0 discloses "a flue gas circulating fluidized bed combined desulfurization and mercury removal device and method", which removes sulfur dioxide and mercury by adding quicklime and activated carbon to the circulating fluidized bed reactor. Although this method achieves the combined removal of multiple pollutants, the inability to remove nitrogen oxides is a significant shortcoming. In addition, activated carbon is expensive, resulting in high operating costs. At the same time, the removal of carbon monoxide in flue gas is also a major challenge. Therefore, we propose a catalyst and flue gas treatment process for removing carbon monoxide from flue gas. Summary of the Invention
[0003] (a) Technical problems to be solved
[0004] To address the shortcomings of existing technologies, this invention provides a catalyst and flue gas treatment process for eliminating carbon monoxide in flue gas, thus solving the aforementioned problems.
[0005] (II) Technical Solution
[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: a flue gas treatment process, comprising the following steps:
[0007] S1: The flue gas to be treated is introduced into the carbon monoxide incinerator, and fuel and catalyst are added to the carbon monoxide incinerator to burn off the carbon monoxide in the flue gas.
[0008] S2: The flue gas to which carbon monoxide has been removed is fed into the SNCR denitrification unit for selective non-catalytic reduction denitrification treatment to obtain denitrified flue gas;
[0009] S3: Waste heat is recovered from the denitrification flue gas that has passed through step S2 by a waste heat boiler, and then the flue gas with recovered waste heat is cooled by a quench tower.
[0010] S4: The cooled flue gas is fed into the neutralization reaction tower for flue gas desulfurization treatment to obtain desulfurized flue gas;
[0011] S5: The flue gas that has undergone desulfurization and denitrification is passed into a dust collector for dust removal treatment to obtain dust-removed flue gas;
[0012] S6: The flue gas after dust removal is introduced into the primary and secondary alkaline spray towers by an induced draft fan for acid removal treatment, and then discharged through the chimney.
[0013] Preferably, the catalyst used in S1 to eliminate carbon monoxide includes copper oxide, manganese oxide and tin oxide, wherein the relative mass ratio of copper, manganese and tin is (20-30):(40-60):(5-15).
[0014] Preferably, the catalyst further includes oxides of other metals, wherein the other metals are selected based on the following: the ionic radius of the other metal is the same as or similar to that of copper, manganese, and tin, and the coordination number is the same; and the outer electrons of the other metal do not bind to surface hydroxyl radicals or the outer electrons can prevent the inner electrons from binding to hydroxyl radicals.
[0015] Preferably, the reducing agent used in the selective non-catalytic reduction denitrification treatment of the flue gas in step S2 is urea, and the urea solution is injected into the flue gas to eliminate carbon monoxide at an air pressure of 0.4-0.5 MPa.
[0016] S21: Urea is pumped into the urea solution preparation tank and industrial water is added and stirred to form a urea solution reducing agent;
[0017] S22: Connect the urea solution preparation tank to the SNCR denitrification device, and spray the urea solution into the SNCR denitrification device through a spray pump to react with the flue gas that has eliminated carbon monoxide to produce a denitrification reaction.
[0018] Preferably, the concentration of the urea solution is 40-55 wt%.
[0019] Preferably, the quench tower in S3 is connected to a quench atomizing pump, and the inlet of the quench atomizing pump is connected to an alkali preparation tank.
[0020] Preferably, in step S4, the flue gas is introduced into the neutralization reaction tower for flue gas desulfurization treatment using activated slaked lime. Specifically, this includes connecting the outlet of the slaked lime storage tank to the inlet of a screw feeder, connecting the outlet of the screw feeder to the neutralization reaction tower, and conveying the activated slaked lime to the neutralization reaction tower via the screw feeder to perform a desulfurization reaction between the activated slaked lime and the cooled flue gas.
[0021] A rotary valve for controlling the supply of hydrated lime is installed between the outlet of the hydrated lime storage tank and the inlet of the screw feeder.
[0022] Preferably, the dust collector used for dust removal treatment of flue gas in S5 includes a primary bag filter and a secondary bag filter, and the flue gas passes through the bag filter at a wind speed of 2 to 4 m / min when performing dust removal treatment.
[0023] Preferably, in step S5, the flue gas is humidified before dust removal. The humidified flue gas is then blown into a bag filter. Some of the gaseous sulfur dioxide molecules in the flue gas react directly with quicklime for desulfurization, while others react with the alkaline film formed on the surface of the filter bag of the bag filter by quicklime adsorption, thereby solidifying the gaseous sulfur dioxide molecules in the flue gas. The solidified material, quicklime, and dust produced by flue gas desulfurization are filtered out by the bag filter and discharged from the ash outlet of the bag filter.
[0024] Preferably, in step S6, the flue gas is introduced into the primary and secondary alkaline spray towers by an induced draft fan for acid removal treatment. Specifically, this includes connecting a spray pump between the primary and secondary alkaline spray towers and the alkaline solution tank, and using the spray pump to spray the alkaline solution into the alkaline spray towers to react with the flue gas for acid removal.
[0025] Preferably, in step S6, the ammonia removal treatment is performed before the dust removal flue gas is introduced into the primary and secondary alkaline spray towers. Specifically, this includes: providing a fixed-bed reactor, placing the ammonia removal agent in the fixed-bed reactor, and introducing the dust removal flue gas into the fixed-bed reactor at 110-160°C to allow the dust removal flue gas to contact the ammonia removal agent. After the reaction, acid removal treatment is performed. The ammonia removal agent is a solid powdered ammonia removal agent, a solid granular ammonia removal agent, or a solid honeycomb ammonia removal agent.
[0026] (III) Beneficial Effects
[0027] Compared with the prior art, the present invention provides a flue gas treatment process with the following beneficial effects:
[0028] 1. The flue gas treatment process uses an SNCR denitrification device, which requires less floor space and has a simpler system structure compared to SCR equipment, greatly reducing the amount of construction work and shortening the project implementation time.
[0029] SNCR denitrification does not cause pressure damage in the entire denitrification process, so there is no need to increase the induced draft fan head. For retrofitted units, there is no need to modify the induced draft fan. This reduces both investment and construction period for retrofitting.
[0030] The entire denitrification and reduction process in SNCR denitrification takes place inside the boiler, eliminating the need for a separate denitrification reactor. The reducing agent is injected into the flue gas through nozzles installed on the boiler wall. A suitable boiler heat setting provides the energy for the reaction, allowing the NOx waste gas to be reduced. More importantly, the elimination of the denitrification reactor, reactor support steel structure, and associated flue gas ducts through SNCR significantly reduces costs and installation work. It also facilitates easier maintenance and repair after operation.
[0031] 2. In this flue gas treatment process, the flue gas is humidified before dust removal. The humidified flue gas is then blown into a bag filter. Some of the gaseous sulfur dioxide molecules in the flue gas react directly with quicklime for desulfurization, while others react with the alkaline film formed on the surface of the filter bag of the bag filter by quicklime for desulfurization. This process solidifies the gaseous sulfur dioxide molecules in the flue gas.
[0032] 3. This flue gas treatment process can stably achieve emission standards, maintaining the advanced nature of enterprise environmental protection in the foreseeable future. Through the environmental and safety improvement and quality transformation of this invention, environmental management becomes more standardized and energy-efficient, significantly improving environmental and social benefits and greatly reducing energy consumption. This invention achieves the goals of safety transformation, environmental protection, energy conservation and emission reduction, which is of great significance to improving the local ecological environment.
[0033] 4. In this flue gas treatment process, a fixed-bed reactor is provided after the flue gas is dusted again. The ammonia removal agent is placed in the fixed-bed reactor. At 110-160°C, the dust-removed flue gas is introduced into the fixed-bed reactor so that the dust-removed flue gas comes into contact with the ammonia removal agent. After the reaction, acid removal treatment is performed. The ammonia removal agent is a solid powder ammonia removal agent, a solid granular ammonia removal agent, or a solid honeycomb ammonia removal agent to prevent ammonia escape and ensure complete ammonia removal.
[0034] 5. This flue gas treatment process, by reformulating a catalyst for eliminating carbon monoxide, includes: copper oxide, manganese oxide, tin oxide, and oxides of other metals, wherein the other metals are selected based on the following: the ionic radius of the other metals is the same as or similar to that of copper, manganese, and tin, and they have the same coordination number; and the outer electrons of the other metals do not combine with surface hydroxyl ions or the outer electrons can prevent the inner electrons from combining with hydroxyl ions; the activation time of this catalyst is significantly extended, and it can more effectively remove carbon monoxide in the concentration range of 10,000 ppm. Attached Figure Description
[0035] Figure 1 This is a schematic diagram of the flue gas treatment process of the present invention. Detailed Implementation
[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.
[0037] Please see Figure 1 A flue gas treatment process includes the following steps:
[0038] S1: The flue gas to be treated is introduced into the carbon monoxide incinerator, and fuel and catalyst are added to the carbon monoxide incinerator to burn off the carbon monoxide in the flue gas.
[0039] S2: The flue gas to which carbon monoxide has been removed is fed into the SNCR denitrification unit for selective non-catalytic reduction denitrification treatment to obtain denitrified flue gas;
[0040] The SNCR denitrification unit requires less floor space and has a simpler system structure compared to the SCR unit, which greatly reduces the amount of construction work and shortens the project implementation time.
[0041] SNCR denitrification does not cause pressure damage in the entire denitrification process, so there is no need to increase the induced draft fan head. For retrofitted units, there is no need to modify the induced draft fan. This reduces both investment and construction period for retrofitting.
[0042] The entire denitrification and reduction process in the SNCR denitrification technology takes place inside the boiler, eliminating the need for a separate denitrification reactor. The reducing agent is injected into the flue gas through nozzles installed on the boiler wall. The appropriate boiler heat provides the energy for the reaction, allowing the NOx waste gas to be reduced. More importantly, the elimination of the denitrification reactor, its supporting steel structure, and associated flue gas ducts significantly reduces costs and installation work. Furthermore, it facilitates easier maintenance and repair after operation.
[0043] S3: Waste heat is recovered from the denitrification flue gas that has passed through step S2 by a waste heat boiler, and then the flue gas with recovered waste heat is cooled by a quench tower.
[0044] S4: The cooled flue gas is fed into the neutralization reaction tower for flue gas desulfurization treatment to obtain desulfurized flue gas;
[0045] S5: The flue gas that has undergone desulfurization and denitrification is passed into a dust collector for dust removal treatment to obtain dust-removed flue gas;
[0046] S6: The flue gas after dust removal is introduced into the primary and secondary alkaline spray towers by an induced draft fan for acid removal treatment, and then discharged through the chimney.
[0047] The catalysts used in S1 to eliminate carbon monoxide include copper oxide, manganese oxide and tin oxide, wherein the relative mass ratio of copper, manganese and tin is (20-30):(40-60):(5-15).
[0048] The catalyst also includes oxides of other metals, wherein the other metals are selected based on the following: the ionic radius of the other metal is the same as or similar to that of copper, manganese and tin and the same coordination number; and the outer electrons of the other metal do not bind to surface hydroxyl groups or the outer electrons can prevent the inner electrons from binding to hydroxyl groups.
[0049] The catalyst preparation method includes: obtaining a predetermined amount of a predetermined concentration of... , and Solution; mixing the solutions and heating the mixture; adding a predetermined amount dropwise to the prepared mixture. or or or The solution is stirred until the pH of the mixed solution reaches the range of 8 to 9; the mixture is sealed and stirred, and the precipitate is centrifuged and washed, then dried in a drying oven to obtain a solid powder; and the obtained solid powder is placed in a muffle furnace for calcination to obtain a catalyst, wherein the relative mass ratio of Cu, Mn and Sn in the obtained catalyst is (10 to 30): (20 to 60): (3 to 15).
[0050] Example 1
[0051] Obtain a 20wt% concentration 40wt% aqueous solution Aqueous solution and 9wt% concentration Aqueous solution; mixing solutions and heating the mixture; adding a predetermined amount dropwise to the prepared mixture. The mixture is stirred until the pH of the mixed solution reaches 8.5; the mixture is then sealed and stirred, and the precipitate is centrifuged and washed, and then dried in a drying oven to obtain a solid powder; the obtained solid powder is then placed in a muffle furnace and calcined to obtain a catalyst, wherein the relative mass ratio of Cu, Mn and Sn in the obtained catalyst is 20:40:9.
[0052] In S2, urea is used as the reducing agent for selective non-catalytic reduction denitrification of flue gas. The urea solution is injected into the flue gas to eliminate carbon monoxide at an air pressure of 0.5 MPa.
[0053] S21: Urea is pumped into the urea solution preparation tank and industrial water is added and stirred to form a urea solution reducing agent. The concentration of the urea solution is 55 wt%.
[0054] S22: Connect the urea solution preparation tank to the SNCR denitrification device, and spray the urea solution into the SNCR denitrification device through a spray pump to react with the flue gas containing carbon monoxide to remove NOx contained in the flue gas.
[0055] The S3 quench tower is connected to a quench atomizing pump, and the inlet of the quench atomizing pump is connected to an alkali solution preparation tank. The alkali solution is used to absorb the acidic components in the flue gas. Under normal circumstances, the flue gas temperature emitted by the waste heat boiler can reach 550℃, while the formation temperature of dioxins is below 300℃. Therefore, it is necessary to minimize the residence time of the flue gas in this temperature range to prevent the re-formation of dioxins. The most common cooling method is spraying alkali solution, which allows for full contact with the flue gas, rapidly removing a large amount of heat and lowering the flue gas temperature to below 200℃. Furthermore, the sprayed alkali solution can neutralize the acidic components in the flue gas and remove HCl.
[0056] In S4, flue gas is introduced into the neutralization reaction tower for flue gas desulfurization treatment using activated slaked lime. Specifically, the process involves connecting the outlet of the slaked lime storage tank to the inlet of a screw feeder, and the outlet of the screw feeder to the neutralization reaction tower. The activated slaked lime is then transported to the neutralization reaction tower via the screw feeder, where it reacts with the cooled flue gas to adsorb dioxins and other substances contained in the flue gas, thus purifying the flue gas.
[0057] A rotary valve is installed between the outlet of the quicklime storage tank and the inlet of the screw feeder to control the supply of quicklime, so as to facilitate the control of the replenishment of active quicklime.
[0058] The dust collectors used for dust removal in S5 include a primary bag filter and a secondary bag filter, and the flue gas passes through the bag filter at a wind speed of 3 m / min.
[0059] Before dust removal, the flue gas in S5 is humidified. The humidified flue gas is then blown into the bag filter. Some of the gaseous sulfur dioxide molecules in the flue gas react directly with quicklime for desulfurization, while others react with the alkaline film formed on the surface of the filter bags of the bag filter by quicklime adsorption, thus solidifying the gaseous sulfur dioxide molecules in the flue gas. The solidified products, quicklime, and dust produced by flue gas desulfurization are filtered out by the bag filter and discharged from the ash outlet of the bag filter.
[0060] In S6, the flue gas is introduced into the primary and secondary alkaline spray towers by an induced draft fan for acid removal treatment. Specifically, this includes connecting the primary and secondary alkaline spray towers to the alkaline solution tank with a spray pump, and using the spray pump to spray the alkaline solution into the alkaline spray towers to react with the flue gas for acid removal.
[0061] In S6, ammonia removal treatment is performed before the dust removal flue gas is introduced into the primary and secondary alkaline spray towers. Specifically, this includes: providing a fixed-bed reactor, placing the ammonia removal agent inside the fixed-bed reactor, and introducing the dust removal flue gas into the fixed-bed reactor at 140°C to allow the dust removal flue gas to contact the ammonia removal agent. After the reaction, acid removal treatment is performed. The ammonia removal agent is a solid powdered ammonia removal agent, a solid granular ammonia removal agent, or a solid honeycomb ammonia removal agent to prevent ammonia escape and ensure the removal of ammonia components.
[0062] Example 2
[0063] Obtain a 10wt% concentration Aqueous solution, 20wt% concentration Aqueous solutions and 3wt% concentration Aqueous solution; mixing solutions and heating the mixture; adding a predetermined amount dropwise to the prepared mixture. The mixture is stirred until the pH of the mixed solution reaches 8.5; the mixture is then sealed and stirred, and the precipitate is centrifuged and washed, and then dried in a drying oven to obtain a solid powder; the obtained solid powder is then placed in a muffle furnace for calcination to obtain a catalyst, wherein the relative mass ratio of Cu, Mn and Sn in the obtained catalyst is 10:20:3.
[0064] In S2, urea is used as the reducing agent for selective non-catalytic reduction denitrification of flue gas. The urea solution is injected into the flue gas to eliminate carbon monoxide at an air pressure of 0.5 MPa.
[0065] S21: Urea is pumped into the urea solution preparation tank and industrial water is added and stirred to form a urea solution reducing agent. The concentration of the urea solution is 55 wt%.
[0066] S22: Connect the urea solution preparation tank to the SNCR denitrification device, and spray the urea solution into the SNCR denitrification device through a spray pump to react with the flue gas containing carbon monoxide to remove NOx contained in the flue gas.
[0067] The S3 quench tower is connected to a quench atomizing pump, and the inlet of the quench atomizing pump is connected to an alkali solution preparation tank. The alkali solution is used to absorb the acidic components in the flue gas. Under normal circumstances, the flue gas temperature emitted by the waste heat boiler can reach 550℃, while the formation temperature of dioxins is below 300℃. Therefore, it is necessary to minimize the residence time of the flue gas in this temperature range to prevent the re-formation of dioxins. The most common cooling method is spraying alkali solution, which allows for full contact with the flue gas, rapidly removing a large amount of heat and lowering the flue gas temperature to below 200℃. Furthermore, the sprayed alkali solution can neutralize the acidic components in the flue gas and remove HCl.
[0068] In S4, flue gas is introduced into the neutralization reaction tower for flue gas desulfurization treatment using activated slaked lime. Specifically, the process involves connecting the outlet of the slaked lime storage tank to the inlet of a screw feeder, and the outlet of the screw feeder to the neutralization reaction tower. The activated slaked lime is then transported to the neutralization reaction tower via the screw feeder, where it reacts with the cooled flue gas to adsorb dioxins and other substances contained in the flue gas, thus purifying the flue gas.
[0069] A rotary valve is installed between the outlet of the quicklime storage tank and the inlet of the screw feeder to control the supply of quicklime, so as to facilitate the control of the replenishment of active quicklime.
[0070] The dust collectors used for dust removal in S5 include a primary bag filter and a secondary bag filter, and the flue gas passes through the bag filter at a wind speed of 3 m / min.
[0071] Before dust removal, the flue gas in S5 is humidified. The humidified flue gas is then blown into the bag filter. Some of the gaseous sulfur dioxide molecules in the flue gas react directly with quicklime for desulfurization, while others react with the alkaline film formed on the surface of the filter bags of the bag filter by quicklime adsorption, thus solidifying the gaseous sulfur dioxide molecules in the flue gas. The solidified products, quicklime, and dust produced by flue gas desulfurization are filtered out by the bag filter and discharged from the ash outlet of the bag filter.
[0072] In S6, the flue gas is introduced into the primary and secondary alkaline spray towers by an induced draft fan for acid removal treatment. Specifically, this includes connecting the primary and secondary alkaline spray towers to the alkaline solution tank with a spray pump, and using the spray pump to spray the alkaline solution into the alkaline spray towers to react with the flue gas for acid removal.
[0073] In S6, ammonia removal treatment is performed before the dust removal flue gas is introduced into the primary and secondary alkaline spray towers. Specifically, this includes: providing a fixed-bed reactor, placing the ammonia removal agent inside the fixed-bed reactor, and introducing the dust removal flue gas into the fixed-bed reactor at 140°C to allow the dust removal flue gas to contact the ammonia removal agent. After the reaction, acid removal treatment is performed. The ammonia removal agent is a solid powdered ammonia removal agent, a solid granular ammonia removal agent, or a solid honeycomb ammonia removal agent to prevent ammonia escape and ensure the removal of ammonia components.
[0074] Example 3
[0075] Obtain a 30wt% concentration Aqueous solution, 60wt% concentration Aqueous solutions and 15wt% concentration Aqueous solution; mixing solutions and heating the mixture; adding a predetermined amount dropwise to the prepared mixture. The mixture is stirred until the pH of the mixed solution reaches 8.5; the mixture is then sealed and stirred, and the precipitate is centrifuged and washed, and then dried in a drying oven to obtain a solid powder; the obtained solid powder is then placed in a muffle furnace for calcination to obtain a catalyst, wherein the relative mass ratio of Cu, Mn and Sn in the obtained catalyst is 30:60:15.
[0076] In S2, urea is used as the reducing agent for selective non-catalytic reduction denitrification of flue gas. The urea solution is injected into the flue gas to eliminate carbon monoxide at an air pressure of 0.5 MPa.
[0077] S21: Urea is pumped into the urea solution preparation tank and industrial water is added and stirred to form a urea solution reducing agent. The concentration of the urea solution is 55 wt%.
[0078] S22: Connect the urea solution preparation tank to the SNCR denitrification device, and spray the urea solution into the SNCR denitrification device through a spray pump to react with the flue gas containing carbon monoxide to remove NOx contained in the flue gas.
[0079] The S3 quench tower is connected to a quench atomizing pump, and the inlet of the quench atomizing pump is connected to an alkali solution preparation tank. The alkali solution is used to absorb the acidic components in the flue gas. Under normal circumstances, the flue gas temperature emitted by the waste heat boiler can reach 550℃, while the formation temperature of dioxins is below 300℃. Therefore, it is necessary to minimize the residence time of the flue gas in this temperature range to prevent the re-formation of dioxins. The most common cooling method is spraying alkali solution, which allows for full contact with the flue gas, rapidly removing a large amount of heat and lowering the flue gas temperature to below 200℃. Furthermore, the sprayed alkali solution can neutralize the acidic components in the flue gas and remove HCl.
[0080] In S4, flue gas is introduced into the neutralization reaction tower for flue gas desulfurization treatment using activated slaked lime. Specifically, the process involves connecting the outlet of the slaked lime storage tank to the inlet of a screw feeder, and the outlet of the screw feeder to the neutralization reaction tower. The activated slaked lime is then transported to the neutralization reaction tower via the screw feeder, where it reacts with the cooled flue gas to adsorb dioxins and other substances contained in the flue gas, thus purifying the flue gas.
[0081] A rotary valve is installed between the outlet of the quicklime storage tank and the inlet of the screw feeder to control the supply of quicklime, so as to facilitate the control of the replenishment of active quicklime.
[0082] The dust collectors used for dust removal in S5 include a primary bag filter and a secondary bag filter, and the flue gas passes through the bag filter at a wind speed of 3 m / min.
[0083] Before dust removal, the flue gas in S5 is humidified. The humidified flue gas is then blown into the bag filter. Some of the gaseous sulfur dioxide molecules in the flue gas react directly with quicklime for desulfurization, while others react with the alkaline film formed on the surface of the filter bags of the bag filter by quicklime adsorption, thus solidifying the gaseous sulfur dioxide molecules in the flue gas. The solidified products, quicklime, and dust produced by flue gas desulfurization are filtered out by the bag filter and discharged from the ash outlet of the bag filter.
[0084] In S6, the flue gas is introduced into the primary and secondary alkaline spray towers by an induced draft fan for acid removal treatment. Specifically, this includes connecting the primary and secondary alkaline spray towers to the alkaline solution tank with a spray pump, and using the spray pump to spray the alkaline solution into the alkaline spray towers to react with the flue gas for acid removal.
[0085] In S6, ammonia removal treatment is performed before the dust removal flue gas is introduced into the primary and secondary alkaline spray towers. Specifically, this includes: providing a fixed-bed reactor, placing the ammonia removal agent inside the fixed-bed reactor, and introducing the dust removal flue gas into the fixed-bed reactor at 140°C to allow the dust removal flue gas to contact the ammonia removal agent. After the reaction, acid removal treatment is performed. The ammonia removal agent is a solid powdered ammonia removal agent, a solid granular ammonia removal agent, or a solid honeycomb ammonia removal agent to prevent ammonia escape and ensure the removal of ammonia components.
[0086] Comparative Example
[0087] Prepare a 2 mol / L solution of copper nitrate, tin tetrachloride, and sodium carbonate. Stir to obtain a mixed solution of copper and tin sources. Add sodium carbonate dropwise to the solution while stirring, control the pH value at the titration endpoint to be 8, continue stirring for 2 hours, and then let it stand for 10 hours. Filter and wash the resulting mixed solution until the TDS value is below 20. Dry the resulting filter cake in an oven at 110℃ for 12 hours. Calcine the resulting solid powder in a muffle furnace at 350℃ for 6 hours to obtain the catalyst.
[0088] The catalysts prepared in Examples 1 to 3 and the comparative example were respectively used in carbon monoxide incinerators with the same temperature, flue gas volume, and carbon monoxide concentration of 12000 ppm. The reaction time of each catalyst and the residual carbon monoxide concentration in the carbon monoxide incinerator were recorded. The results are as follows:
[0089]
[0090] The data above show that, compared with the comparative example, the catalysts obtained in the examples have a significantly longer activation time and can more effectively remove carbon monoxide in the concentration range of 10,000 ppm.
[0091] In S2, urea is used as the reducing agent for selective non-catalytic reduction denitrification of flue gas. The urea solution is injected into the flue gas to eliminate carbon monoxide at an air pressure of 0.4–0.5 MPa.
[0092] S21: Urea is pumped into a urea solution preparation tank and industrial water is added and stirred to form a urea solution reducing agent. The concentration of the urea solution is 40-55 wt%.
[0093] S22: Connect the urea solution preparation tank to the SNCR denitrification device, and spray the urea solution into the SNCR denitrification device through a spray pump to react with the flue gas containing carbon monoxide to remove NOx contained in the flue gas.
[0094] The S3 quench tower is connected to a quench atomizing pump, and the inlet of the quench atomizing pump is connected to an alkali solution preparation tank. The alkali solution is used to absorb the acidic components in the flue gas. Under normal circumstances, the flue gas temperature emitted by the waste heat boiler can reach 550℃, while the formation temperature of dioxins is between 250 and 500℃. Therefore, it is necessary to minimize the residence time of the flue gas in this temperature range to prevent the re-formation of dioxins. The most common cooling method is spraying alkali solution, which allows for full contact with the flue gas, rapidly removing a large amount of heat and lowering the flue gas temperature to below 200℃. Furthermore, the sprayed alkali solution can neutralize the acidic components in the flue gas and remove HCl.
[0095] In S4, flue gas is introduced into the neutralization reaction tower for flue gas desulfurization treatment using activated slaked lime. Specifically, the process involves connecting the outlet of the slaked lime storage tank to the inlet of a screw feeder, and the outlet of the screw feeder to the neutralization reaction tower. The activated slaked lime is then transported to the neutralization reaction tower via the screw feeder, where it reacts with the cooled flue gas to adsorb dioxins and other substances contained in the flue gas, thus purifying the flue gas.
[0096] A rotary valve is installed between the outlet of the quicklime storage tank and the inlet of the screw feeder to control the supply of quicklime, so as to facilitate the control of the replenishment of active quicklime.
[0097] The dust collectors used for dust removal in S5 include a primary bag filter and a secondary bag filter, and the flue gas passes through the bag filter at a wind speed of 2 to 4 m / min.
[0098] Before dust removal, the flue gas in S5 is humidified. The humidified flue gas is then blown into the bag filter. Some of the gaseous sulfur dioxide molecules in the flue gas react directly with quicklime for desulfurization, while others react with the alkaline film formed on the surface of the filter bags of the bag filter by quicklime adsorption, thus solidifying the gaseous sulfur dioxide molecules in the flue gas. The solidified products, quicklime, and dust produced by flue gas desulfurization are filtered out by the bag filter and discharged from the ash outlet of the bag filter.
[0099] In S6, the flue gas is introduced into the primary and secondary alkaline spray towers by an induced draft fan for acid removal treatment. Specifically, this includes connecting the primary and secondary alkaline spray towers to the alkaline solution tank with a spray pump, and using the spray pump to spray the alkaline solution into the alkaline spray towers to react with the flue gas for acid removal.
[0100] In S6, ammonia removal treatment is performed before the dust removal flue gas is introduced into the primary and secondary alkaline spray towers. Specifically, this includes: providing a fixed-bed reactor, placing the ammonia removal agent inside the fixed-bed reactor, and introducing the dust removal flue gas into the fixed-bed reactor at 110-160°C to allow the dust removal flue gas to contact the ammonia removal agent. After the reaction, acid removal treatment is performed. The ammonia removal agent is a solid powdered ammonia removal agent, a solid granular ammonia removal agent, or a solid honeycomb ammonia removal agent to prevent ammonia escape and ensure the removal of ammonia components.
[0101] This flue gas treatment process can stably achieve emission standards, maintaining the advanced nature of enterprise environmental protection in the foreseeable future. Through the environmental and safety improvement and quality transformation of this invention, environmental management becomes more standardized and energy-efficient, significantly improving environmental and social benefits and greatly reducing energy consumption. This invention achieves the goals of safety transformation, environmental protection, energy conservation and emission reduction, which is of great significance to improving the local ecological environment.
[0102] Although embodiments of the invention 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 to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A flue gas treatment process, characterized in that, Includes the following steps: S1: The flue gas to be treated is introduced into the carbon monoxide incinerator, and fuel and catalyst are added to the carbon monoxide incinerator to burn off the carbon monoxide in the flue gas. S2: The flue gas to which carbon monoxide has been removed is fed into the SNCR denitrification unit for selective non-catalytic reduction denitrification treatment to obtain denitrified flue gas; S3: Waste heat is recovered from the denitrification flue gas that has passed through step S2 by a waste heat boiler, and then the flue gas with recovered waste heat is cooled by a quench tower. S4: The cooled flue gas is fed into the neutralization reaction tower for flue gas desulfurization treatment to obtain desulfurized flue gas; S5: The flue gas that has undergone desulfurization and denitrification is passed into a dust collector for dust removal treatment to obtain dust-removed flue gas; S6: The flue gas after dust removal is introduced into the primary and secondary alkaline spray towers by an induced draft fan for acid removal treatment, and then it can be discharged through the chimney; The catalyst in S1 includes copper oxide, manganese oxide and tin oxide, wherein the relative mass ratio of copper, manganese and tin is (20-30):(40-60):(5-15); The catalyst also includes oxides of other metals, wherein the other metals are selected based on the following criteria: the ionic radius of the other metal is the same as or similar to that of copper, manganese, and tin and the coordination number is the same; and the outer electrons of the other metal do not bind to surface hydroxyl radicals or the outer electrons can prevent the inner electrons from binding to hydroxyl radicals. In step S2, the reducing agent used for selective non-catalytic reduction denitrification of the flue gas is urea. The urea solution is injected into the flue gas to eliminate carbon monoxide at an air pressure of 0.4–0.5 MPa. S21: Urea is pumped into the urea solution preparation tank and industrial water is added and stirred to form a urea solution reducing agent; S22: Connect the urea solution preparation tank to the SNCR denitrification device, and spray the urea solution into the SNCR denitrification device through a spray pump to react with the flue gas that has eliminated carbon monoxide to produce a denitrification reaction; In S6, the flue gas is introduced into the primary and secondary alkaline spray towers by an induced draft fan for acid removal treatment. Specifically, this includes connecting the primary and secondary alkaline spray towers to the alkaline solution tank with a spray pump, and spraying the alkaline solution into the alkaline spray towers to react with the flue gas for acid removal. In step S6, ammonia removal treatment is performed before the dust removal flue gas is introduced into the primary and secondary alkaline spray towers. Specifically, this includes: providing a fixed-bed reactor, placing the ammonia removal agent in the fixed-bed reactor, and introducing the dust removal flue gas into the fixed-bed reactor at 110-160°C to allow the dust removal flue gas to contact the ammonia removal agent. After the reaction, acid removal treatment is performed. The ammonia removal agent is a solid powdered ammonia removal agent, a solid granular ammonia removal agent, or a solid honeycomb ammonia removal agent.
2. The flue gas treatment process according to claim 1, characterized in that, The concentration of the urea solution is 40–55 wt%.
3. The flue gas treatment process according to claim 1, characterized in that, The S3 quench tower is connected to a quench atomizing pump, and the inlet of the quench atomizing pump is connected to an alkali preparation tank.
4. The flue gas treatment process according to claim 1, characterized in that, In S4, flue gas is introduced into the neutralization reaction tower for flue gas desulfurization treatment using activated slaked lime. Specifically, the process involves connecting the outlet of the slaked lime storage tank to the inlet of a screw feeder, connecting the outlet of the screw feeder to the neutralization reaction tower, and conveying the activated slaked lime to the neutralization reaction tower via the screw feeder to perform a desulfurization reaction between the activated slaked lime and the cooled flue gas. A rotary valve for controlling the supply of hydrated lime is installed between the outlet of the hydrated lime storage tank and the inlet of the screw feeder.
5. The flue gas treatment process according to claim 1, characterized in that, The dust collector used for dust removal treatment of flue gas in S5 includes a primary bag filter and a secondary bag filter, and the flue gas passes through the bag filter at a wind speed of 2 to 4 m / min when performing dust removal treatment.
6. The flue gas treatment process according to claim 5, characterized in that, Before dust removal, the flue gas in step S5 is humidified. The humidified flue gas is then blown into a bag filter. Some of the gaseous sulfur dioxide molecules in the flue gas react directly with quicklime for desulfurization, while others react with the alkaline film formed on the surface of the filter bags of the bag filter by the quicklime, thereby solidifying the gaseous sulfur dioxide molecules in the flue gas. The solidified material, quicklime, and dust produced by flue gas desulfurization are filtered out by the bag filter and discharged from the ash outlet of the bag filter.