A flue gas desulfurization and denitrification and dust removal process for waste incineration power plants
By combining a circulating fluidized bed reactor with ceramic fiber catalytic filter tubes, the problems of short catalyst life and high cost in the flue gas treatment of waste incineration power plants have been solved, achieving efficient and stable flue gas purification and meeting ultra-low emission standards.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ANHUI ZISHUO ENVIRONMENT TECH CO LTD
- Filing Date
- 2026-03-31
- Publication Date
- 2026-06-09
AI Technical Summary
Existing flue gas treatment technologies for waste-to-energy plants suffer from problems such as short catalyst lifespan, severe equipment wear and blockage, high operating costs, and complex processes, making it difficult to meet ultra-low emission requirements.
A circulating fluidized bed reactor combined with ceramic fiber catalytic filter tubes is used for flue gas desulfurization and selective catalytic reduction denitrification. γ-Al2O3 is used as a carrier, and the catalyst is doped with Mn, V and Ce multi-element active components. Combined with a waterproof coating, it integrates dust removal, denitrification and dioxin degradation functions.
It has achieved process simplification, equipment streamlining, stable operation, reduced costs, met ultra-low emission requirements, extended catalyst life, and improved denitrification efficiency and dioxin removal rate.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of flue gas treatment technology, specifically relating to a process for flue gas desulfurization, denitrification and dust removal in waste incineration power plants. Background Technology
[0002] With the acceleration of urbanization and the improvement of living standards, the amount of urban domestic waste generated continues to increase. Waste-to-energy incineration, due to its significant reduction, harmlessness, and resource recovery effects, has become one of the main methods of domestic waste treatment in my country. However, the flue gas produced during waste incineration has an extremely complex composition, with major pollutants including particulate matter (dust), acidic gases (such as hydrogen chloride (HCl), sulfur dioxide (SO2), and hydrofluoric acid (HF), and nitrogen oxides (NOx). x The emissions include heavy metals and highly toxic organic compounds such as dioxins. To protect the ecological environment and public health, the national standards for emissions from waste incineration are becoming increasingly stringent, especially regarding NOx. x The ultra-low emission requirements for SO2 and dust pose a huge challenge to flue gas purification technology.
[0003] Currently, domestic waste-to-energy plants generally adopt a combined process route of "SNCR (Selective Non-Catalytic Reduction) + SDA semi-dry deacidification + dry calcium injection + activated carbon injection + bag filter + reserved SCR (Selective Catalytic Reduction)". This process involves initial denitrification via in-furnace SNCR, removal of acidic gases via a semi-dry spray drying deacidification tower (SDA), dry calcium injection as a backup deacidification method, adsorption of dioxins and heavy metals via activated carbon injection, and finally dust removal via a bag filter. Some power plants reserve SCR units at the tail end to meet stricter emission standards. Although this process is mature and reliable, it suffers from drawbacks such as poor operational stability of the denitrification system and short catalyst life. Existing SNCR processes exhibit large fluctuations in denitrification efficiency and high ammonia slip rates. Furthermore, the honeycomb catalyst used in the tail-end SCR unit is prone to alkali metal poisoning, sulfur poisoning, and dust blockage under the complex operating conditions of waste incineration flue gas, leading to rapid catalyst activity decay, short service life, and high replacement costs. In addition, the SCR system requires heating the flue gas to the catalyst's activity temperature window, resulting in significant energy consumption. Meanwhile, to control dioxin and furan emissions, existing processes require continuous spraying of activated carbon powder, resulting in high activated carbon consumption and a high price, significantly increasing operating costs. Furthermore, once the activated carbon becomes saturated, it is discharged with the fly ash, increasing the difficulty and cost of fly ash treatment.
[0004] In summary, existing technologies for treating flue gas from waste incineration power plants suffer from problems such as short catalyst life, severe equipment wear and blockage, high operating costs, and complex processes. Therefore, developing a flue gas desulfurization, denitrification, and dust removal process for waste incineration power plants that is simple in process flow, stable in operation, low in cost, and can meet ultra-low emission requirements is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention
[0005] To address the technical problems existing in current waste-to-energy flue gas treatment technologies, such as short catalyst life, severe atomizer wear, slurry pipeline blockage, high activated carbon operating costs, and complex processes, this invention provides a flue gas desulfurization, denitrification, and dust removal process for waste-to-energy plants. The aim is to simplify the process, stabilize operation, reduce costs, and meet stringent flue gas emission requirements.
[0006] The objective of this invention can be achieved through the following technical solutions: A process for flue gas desulfurization, denitrification, and dust removal in waste incineration power plants includes the following steps: Step 1: The flue gas from the waste incineration boiler outlet is introduced into a circulating fluidized bed reactor for desulfurization treatment. After the desulfurization reaction, the gas-solid mixture is separated by a gas-solid separator, and the desulfurized flue gas is obtained. Step 2: The temperature of the flue gas after desulfurization is adjusted by a burner, and then introduced into an integrated dust and nitrogen removal device with ceramic fiber catalytic filter tubes inside. While filtering dust, selective catalytic reduction denitrification reaction is carried out on the surface and inside of the filter tubes to obtain flue gas after denitrification and dust removal. Step 3: The flue gas after denitrification and dust removal is drawn out and discharged by an induced draft fan.
[0007] As a preferred embodiment of the present invention, the sulfur content of the flue gas at the outlet of the waste incineration boiler in step 1 is ≤800mg / Nm³. 3 .
[0008] In a preferred embodiment of the present invention, in step 2, the temperature of the flue gas after desulfurization is adjusted by the burner to 280-320°C.
[0009] In a preferred embodiment of the present invention, the ceramic fiber catalytic filter tube comprises a ceramic fiber filter tube, a catalyst, and a waterproof coating; the catalyst is uniformly loaded on the outer surface, inner surface, and wall of the ceramic fiber filter tube; and the waterproofing agent is uniformly coated on the outer wall surface of the ceramic fiber filter tube to form a waterproof coating.
[0010] In a preferred embodiment of the present invention, the catalyst in the ceramic fiber catalytic filter tube in step 2 is prepared by the following steps: Oxalic acid was added to deionized water, heated to 50–55 °C, and stirred until homogeneous. Then, MnC₂O₄·2H₂O, NH₄VO₃, and CeO₂ were added, and the mixture was stirred for 2–3 h. γ-Al₂O₃ was added, and the mixture was allowed to stand for 12–16 h for impregnation. After impregnation, the pH was adjusted to 7.8–8.0 with ammonia water, and the mixture was stirred for another 2–3 h. The mixture was then dried in an oven at 105 °C and subsequently calcined at 450–550 °C for 5–6 h to obtain the catalyst.
[0011] As a preferred embodiment of the present invention, the ratio of oxalic acid, deionized water, MnC2O4·2H2O, NH4VO3, CeO2, and γ-Al2O3 is 3.9–4.0 g: 30 mL: 2.7–2.8 g: 1.2–1.3 g: 0.50–0.55 g: 10.5 g.
[0012] The above technical solution utilizes a ceramic fiber catalytic filter tube comprising a ceramic fiber filter tube, a catalyst, and a waterproof coating. The catalyst uses γ-Al₂O₃ as a support, and the active components Mn, V, and Ce are loaded onto the support via an impregnation method. γ-Al₂O₃ itself possesses excellent denitrification catalytic activity; using it as a support allows the catalyst to have high mechanical strength, as well as good water and heat resistance, enabling it to withstand the scouring of flue gas and the impact of dust. After loading Mn, the denitrification efficiency of the catalyst is significantly improved. Mn is calcined to produce MnO. x This not only enhances the oxygen storage capacity of the catalyst and increases the concentration of chemically adsorbed oxygen on the surface, but also provides more acidic sites for multivalent Mn, thereby improving the contact efficiency between reactant molecules and facilitating the denitrification reaction. However, single MnO... x As an active component, it still has shortcomings, such as low NO conversion rate at high temperatures and poor SO2 resistance. Therefore, this invention further introduces small amounts of V and Ce for doping. The introduction of V₂O₅ increases the adsorbed oxygen on the catalyst surface. Even in the presence of SO₂, NH₃ can still react with sufficient surface-adsorbed oxygen, thereby reducing the formation of (NH₄)₂SO₄ or NH₄HSO₄. Simultaneously, under an SO₂ atmosphere, the highly active V₂O₅ preferentially reacts with SO₂, thus reducing the formation of MnO₂. x The active centers of the ceramic fiber filter act as a protective layer, mitigating the poisoning effect of SO2 on the catalyst. The addition of CeO2 allows it to react with SO2 and SO3 to form Ce2(SO4)3, a product that enhances the acidic sites of the catalyst at high temperatures and promotes the adsorption of NH3, thereby improving catalytic activity and enhancing the catalytic reduction reaction capability. Furthermore, the ceramic fiber catalytic filter can effectively adsorb and catalytically degrade dioxins and furans.
[0013] As a preferred embodiment of the present invention, the waterproofing agent in the ceramic fiber catalytic filter tube comprises the following raw materials in parts by weight: The composition includes 5-15 parts methyl silicone resin, 2-8 parts inorganic binder, 1-3 parts silane coupling agent KH-560, 2-5 parts fumed nano-silica, 30-50 parts anhydrous ethanol, and 40-60 parts water. Due to the high humidity of waste incineration flue gas, a waterproof coating is applied to the surface of the filter tube. Water vapor in the flue gas is repelled by the outer waterproof coating and diffuses in gaseous form through the micropores of the coating into the internal catalyst layer, where a selective catalytic reduction denitrification reaction occurs on the catalyst surface. Simultaneously, the waterproof coating inhibits the penetration of acidic gases, effectively slowing down catalyst poisoning and deactivation, and extending the catalyst's lifespan.
[0014] In a preferred embodiment of the present invention, the inorganic binder is at least one of aluminum sol and silica sol.
[0015] In a preferred embodiment of the present invention, the ceramic fiber catalytic filter tube in step 2 is prepared by the following steps: The ceramic fiber filter tube is impregnated with a catalyst-containing solution, dried at 120°C and calcined at 350-450°C to obtain a catalyst-loaded ceramic fiber filter tube; then a waterproofing agent is sprayed onto the outer surface of the ceramic fiber filter tube, and the thickness of the waterproof coating is controlled to obtain a ceramic fiber catalytic filter tube.
[0016] As a preferred embodiment of the present invention, the thickness of the waterproof coating is controlled at 15–25 μm.
[0017] The beneficial effects of this invention are: This invention employs an integrated dust and nitrogen removal device as its core treatment equipment, combining dust removal, nitrogen removal, and removal of organic pollutants such as dioxins and furans into a single unit. Particulate matter is efficiently captured through the surface filtration of ceramic fiber catalytic filter tubes, while the catalyst loaded on the filter tubes simultaneously removes NO... x The process selectively catalytically reduces nitrogen to nitrogen (N2), and simultaneously adsorbs and degrades dioxins by utilizing the porous structure of the filter tube and the physicochemical properties of the catalyst support. This simplifies the process flow, reduces the number of equipment and floor space required, lowers system investment and operating and maintenance costs, and meets stringent emission requirements for waste incineration flue gas.
[0018] The ceramic fiber catalytic filter tube used in this invention employs a catalyst supported on γ-Al₂O₃, prepared through the synergistic doping of Mn, V, and Ce as multi-component active components. MnO x The increased oxygen storage capacity and surface acidic sites significantly improve denitrification efficiency; the introduction of V2O5 increases surface adsorption of oxygen, which preferentially reacts with SO2, thereby protecting MnO. xThe active center mitigates sulfur poisoning; Ce2(SO4)3, generated from the reaction of CeO2 with SO2 / SO3, enhances high-temperature acidic sites and promotes NH3 adsorption. Furthermore, the waterproof coating on the outer wall of the filter tube effectively repels water vapor in humid flue gas and hinders the permeation of acidic gases. While ensuring the diffusion of reactant gases, it significantly slows down catalyst poisoning and deactivation, effectively extending catalyst lifespan. This overcomes the shortcomings of traditional honeycomb SCR catalysts, such as susceptibility to alkali metal poisoning, sulfur poisoning, dust clogging, and short lifespan under complex waste incineration conditions.
[0019] This invention provides a flue gas desulfurization, denitrification, and dust removal process for waste-to-energy plants that eliminates the expensive continuous activated carbon injection step in traditional methods, thus avoiding the increased difficulty and cost of fly ash treatment after activated carbon adsorption saturation. The ceramic fiber catalytic filter tube possesses excellent water resistance, heat resistance, and mechanical strength, enabling it to withstand flue gas erosion and dust impact. It exhibits good operational stability, achieving a simplified process, streamlined equipment, and reduced energy consumption, demonstrating promising application prospects. Detailed Implementation
[0020] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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.
[0021] Preparation Example
[0022] Preparation Example 1
[0023] This preparation example provides a ceramic fiber catalytic filter tube, which includes a ceramic fiber filter tube, a catalyst, and a waterproof coating; the catalyst is uniformly loaded on the outer surface, inner surface, and wall of the ceramic fiber filter tube; the waterproofing agent is uniformly coated on the outer wall surface of the ceramic fiber filter tube to form a waterproof coating; The catalyst is prepared through the following steps: 3.9 g of oxalic acid was added to 30 mL of deionized water, heated to 50 °C, and stirred until homogeneous. Then, 2.7 g of MnC₂O₄·2H₂O, 1.2 g of NH₄VO₃, and 0.50 g of CeO₂ were added, and the mixture was stirred for 2 h. Then, 10.5 g of γ-Al₂O₃ was added, and the mixture was allowed to stand for 14 h for impregnation. After impregnation, the pH was adjusted to 7.8 with ammonia water, and the mixture was stirred for another 3 h. The mixture was then dried in an oven at 105 °C and calcined at 550 °C for 5 h to obtain the catalyst.
[0024] The waterproofing agent comprises the following raw materials in parts by weight: 5 parts methyl silicone resin, 2 parts aluminum sol, 1 part silane coupling agent KH-560, 2 parts fumed nano silica, 30 parts anhydrous ethanol, and 40 parts water.
[0025] The ceramic fiber catalytic filter tube is prepared through the following steps: The ceramic fiber filter tube was impregnated with a catalyst-containing solution, dried at 120°C and calcined at 350°C to obtain a catalyst-loaded ceramic fiber filter tube; then a waterproofing agent was sprayed onto the outer surface of the ceramic fiber filter tube, and the thickness of the waterproof coating was controlled to be 15 μm to obtain a ceramic fiber catalytic filter tube.
[0026] Preparation Example 2
[0027] The only difference from Preparation Example 1 is the preparation of the catalyst: The catalyst is prepared through the following steps: Add 4.0 g of oxalic acid to 30 mL of deionized water, heat to 50 °C, and stir until homogeneous. Then add 2.8 g of MnC₂O₄·2H₂O, 1.3 g of NH₄VO₃, and 0.55 g of CeO₂, and stir for 2–3 h. Add 10.5 g of γ-Al₂O₃, and let stand for 14 h for impregnation. After impregnation, adjust the pH to 7.8 with ammonia water, continue stirring for 3 h, dry in an oven at 105 °C, and then calcine at 550 °C for 5 h to obtain the catalyst.
[0028] Preparation Example 3
[0029] The only difference from Preparation Example 1 is the amount of raw material used in the waterproofing agent: The waterproofing agent comprises the following raw materials in parts by weight: 15 parts methyl silicone resin, 7 parts aluminum sol, 2.8 parts silane coupling agent KH-560, 5 parts fumed nano silica, 45 parts anhydrous ethanol, and 60 parts water.
[0030] Preparation Example 3
[0031] The only difference from Preparation Example 1 is the thickness of the waterproof coating in the ceramic fiber catalytic filter tube: The ceramic fiber catalytic filter tube is prepared through the following steps: The ceramic fiber filter tube was impregnated with a catalyst-containing solution, dried at 120°C and calcined at 350°C to obtain a catalyst-loaded ceramic fiber filter tube; then a waterproofing agent was sprayed onto the outer surface of the ceramic fiber filter tube, and the thickness of the waterproof coating was controlled to be 20 μm to obtain a ceramic fiber catalytic filter tube.
[0032] Preparation Example 4
[0033] This preparation example provides a ceramic fiber catalytic filter tube, which includes a ceramic fiber filter tube and a catalyst; the catalyst is uniformly loaded on the outer surface, inner surface and wall of the ceramic fiber filter tube.
[0034] Preparation Example 5
[0035] The only difference from Preparation Example 1 is the preparation of the catalyst: The catalyst is prepared through the following steps: 3.9 g of oxalic acid was added to 30 mL of deionized water, heated to 50 °C, and stirred until homogeneous. Then, 2.7 g of MnC2O4·2H2O was added, and the mixture was stirred for 2 h. 10.5 g of γ-Al2O3 was added, and the mixture was allowed to stand for 14 h for impregnation. After impregnation, the pH was adjusted to 7.8 with ammonia water, and the mixture was stirred for another 3 h. The mixture was then dried in an oven at 105 °C and calcined at 550 °C for 5 h to obtain the catalyst.
[0036] Preparation Example 6
[0037] The only difference from Preparation Example 1 is the preparation of the catalyst: The catalyst is prepared through the following steps: 3.9 g of oxalic acid was added to 30 mL of deionized water, heated to 50 °C, and stirred until homogeneous. Then, 2.7 g of MnC₂O₄·2H₂O and 1.2 g of NH₄VO₃ were added, and the mixture was stirred for 2 h. Then, 10.5 g of γ-Al₂O₃ was added, and the mixture was allowed to stand for 14 h for impregnation. After impregnation, the pH was adjusted to 7.8 with ammonia water, and the mixture was stirred for another 3 h. The mixture was then dried in an oven at 105 °C and calcined at 550 °C for 5 h to obtain the catalyst.
[0038] Example
[0039] Example 1
[0040] This embodiment provides a process for flue gas desulfurization, denitrification, and dust removal in a waste incineration power plant, including the following steps: Step 1: Control the sulfur content of the flue gas from the waste incineration boiler outlet to ≤800mg / Nm³. 3 The gas-solid mixture is then introduced into a circulating fluidized bed reactor for desulfurization. After the desulfurization reaction, the gas-solid mixture is separated by a gas-solid separator to obtain desulfurized flue gas. Step 2: The temperature of the flue gas after desulfurization is adjusted to 280°C using a burner, and then introduced into the dust and nitrogen integrated device filled with ceramic fiber catalytic filter tubes as in Example 1. While filtering dust, selective catalytic reduction denitrification reaction is carried out on the surface and inside of the filter tube to obtain flue gas after denitrification and dust removal. Step 3: The flue gas after denitrification and dust removal is drawn out and discharged by an induced draft fan.
[0041] Example 2
[0042] The only difference from Preparation Example 1 is that the ceramic fiber catalytic filter tube in Preparation Example 1 is replaced with the ceramic fiber catalytic filter tube in Preparation Example 2 in step 2: A process for flue gas desulfurization, denitrification, and dust removal in waste incineration power plants includes the following steps: Step 1: Control the sulfur content of the flue gas from the waste incineration boiler outlet to ≤800mg / Nm³. 3 The gas-solid mixture is then introduced into a circulating fluidized bed reactor for desulfurization. After the desulfurization reaction, the gas-solid mixture is separated by a gas-solid separator to obtain desulfurized flue gas. Step 2: The temperature of the flue gas after desulfurization is adjusted to 280℃ using a burner, and then introduced into the dust and nitrogen integrated device filled with ceramic fiber catalytic filter tubes as in Example 2. While filtering dust, selective catalytic reduction denitrification reaction is carried out on the surface and inside of the filter tube to obtain flue gas after denitrification and dust removal. Step 3: The flue gas after denitrification and dust removal is drawn out and discharged by an induced draft fan.
[0043] Example 3
[0044] The only difference from Preparation Example 1 is that the ceramic fiber catalytic filter tube in Preparation Example 1 is replaced with the ceramic fiber catalytic filter tube in Preparation Example 3 in step 2: A process for flue gas desulfurization, denitrification, and dust removal in waste incineration power plants includes the following steps: Step 1: Control the sulfur content of the flue gas from the waste incineration boiler outlet to ≤800mg / Nm³. 3 The gas-solid mixture is then introduced into a circulating fluidized bed reactor for desulfurization. After the desulfurization reaction, the gas-solid mixture is separated by a gas-solid separator to obtain desulfurized flue gas. Step 2: The temperature of the flue gas after desulfurization is adjusted to 280℃ using a burner, and then introduced into the dust and nitrogen integrated device filled with ceramic fiber catalytic filter tubes as in Example 3. While filtering dust, selective catalytic reduction denitrification reaction is carried out on the surface and inside of the filter tube to obtain the flue gas after denitrification and dust removal. Step 3: The flue gas after denitrification and dust removal is drawn out and discharged by an induced draft fan.
[0045] Example 4
[0046] The only difference from Preparation Example 1 is the temperature of the desulfurized flue gas in step 2: A process for flue gas desulfurization, denitrification, and dust removal in waste incineration power plants includes the following steps: Step 1: Control the sulfur content of the flue gas from the waste incineration boiler outlet to ≤800mg / Nm³. 3The gas-solid mixture is then introduced into a circulating fluidized bed reactor for desulfurization. After the desulfurization reaction, the gas-solid mixture is separated by a gas-solid separator to obtain desulfurized flue gas. Step 2: The temperature of the flue gas after desulfurization is adjusted to 320℃ using a burner, and then introduced into the dust and nitrogen integrated device filled with ceramic fiber catalytic filter tubes as in Example 1. While filtering dust, selective catalytic reduction denitrification reaction is carried out on the surface and inside of the filter tube to obtain flue gas after denitrification and dust removal. Step 3: The flue gas after denitrification and dust removal is drawn out and discharged by an induced draft fan.
[0047] Comparative Example
[0048] Comparative Example 1
[0049] The only difference from Preparation Example 1 is that the ceramic fiber catalytic filter tube in Preparation Example 1 is replaced with the ceramic fiber catalytic filter tube in Preparation Example 4 in step 2: A process for flue gas desulfurization, denitrification, and dust removal in waste incineration power plants includes the following steps: Step 1: Control the sulfur content of the flue gas from the waste incineration boiler outlet to ≤800mg / Nm³. 3 The gas-solid mixture is then introduced into a circulating fluidized bed reactor for desulfurization. After the desulfurization reaction, the gas-solid mixture is separated by a gas-solid separator to obtain desulfurized flue gas. Step 2: The temperature of the flue gas after desulfurization is adjusted to 280℃ using a burner, and then introduced into the dust and nitrogen integrated device filled with ceramic fiber catalytic filter tubes as in Example 4. While filtering dust, selective catalytic reduction denitrification reaction is carried out on the surface and inside of the filter tube to obtain flue gas after denitrification and dust removal. Step 3: The flue gas after denitrification and dust removal is drawn out and discharged by an induced draft fan.
[0050] Comparative Example 2
[0051] The only difference from Preparation Example 1 is that the ceramic fiber catalytic filter tube in Preparation Example 1 is replaced with the ceramic fiber catalytic filter tube in Preparation Example 5 in step 2: A process for flue gas desulfurization, denitrification, and dust removal in waste incineration power plants includes the following steps: Step 1: Control the sulfur content of the flue gas from the waste incineration boiler outlet to ≤800mg / Nm³. 3 The gas-solid mixture is then introduced into a circulating fluidized bed reactor for desulfurization. After the desulfurization reaction, the gas-solid mixture is separated by a gas-solid separator to obtain desulfurized flue gas. Step 2: The temperature of the flue gas after desulfurization is adjusted to 280℃ using a burner, and then introduced into the dust and nitrogen integrated device filled with ceramic fiber catalytic filter tubes as in Example 5. While filtering dust, selective catalytic reduction denitrification reaction is carried out on the surface and inside of the filter tube to obtain flue gas after denitrification and dust removal. Step 3: The flue gas after denitrification and dust removal is drawn out and discharged by an induced draft fan.
[0052] Comparative Example 3
[0053] The only difference from Preparation Example 1 is that the ceramic fiber catalytic filter tube in Preparation Example 1 is replaced with the ceramic fiber catalytic filter tube in Preparation Example 6 in step 2: A process for flue gas desulfurization, denitrification, and dust removal in waste incineration power plants includes the following steps: Step 1: Control the sulfur content of the flue gas from the waste incineration boiler outlet to ≤800mg / Nm³. 3 The gas-solid mixture is then introduced into a circulating fluidized bed reactor for desulfurization. After the desulfurization reaction, the gas-solid mixture is separated by a gas-solid separator to obtain desulfurized flue gas. Step 2: The temperature of the flue gas after desulfurization is adjusted to 280°C using a burner, and then introduced into the dust and nitrogen integrated device filled with ceramic fiber catalytic filter tubes as in Example 6. While filtering dust, selective catalytic reduction denitrification reaction is carried out on the surface and inside of the filter tube to obtain flue gas after denitrification and dust removal. Step 3: The flue gas after denitrification and dust removal is drawn out and discharged by an induced draft fan.
[0054] Comparative Example 4
[0055] The only difference from Preparation Example 1 is the temperature of the desulfurized flue gas in step 2: A process for flue gas desulfurization, denitrification, and dust removal in waste incineration power plants includes the following steps: Step 1: Control the sulfur content of the flue gas from the waste incineration boiler outlet to ≤800mg / Nm³. 3 The gas-solid mixture is then introduced into a circulating fluidized bed reactor for desulfurization. After the desulfurization reaction, the gas-solid mixture is separated by a gas-solid separator to obtain desulfurized flue gas. Step 2: The temperature of the flue gas after desulfurization is adjusted to 260°C using a burner, and then introduced into the dust and nitrogen integrated device filled with ceramic fiber catalytic filter tubes as in Example 1. While filtering dust, selective catalytic reduction denitrification reaction is carried out on the surface and inside of the filter tube to obtain flue gas after denitrification and dust removal. Step 3: The flue gas after denitrification and dust removal is drawn out and discharged by an induced draft fan.
[0056] Comparative Example 5
[0057] The only difference from Preparation Example 1 is the temperature of the desulfurized flue gas in step 2: A process for flue gas desulfurization, denitrification, and dust removal in waste incineration power plants includes the following steps: Step 1: Control the sulfur content of the flue gas from the waste incineration boiler outlet to ≤800mg / Nm³. 3The gas-solid mixture is then introduced into a circulating fluidized bed reactor for desulfurization. After the desulfurization reaction, the gas-solid mixture is separated by a gas-solid separator to obtain desulfurized flue gas. Step 2: The temperature of the flue gas after desulfurization is adjusted to 335℃ using a burner, and then introduced into the dust and nitrogen integrated device filled with ceramic fiber catalytic filter tubes as in Example 1. While filtering dust, selective catalytic reduction denitrification reaction is carried out on the surface and inside of the filter tube to obtain flue gas after denitrification and dust removal. Step 3: The flue gas after denitrification and dust removal is drawn out and discharged by an induced draft fan.
[0058] Performance testing
[0059] The process for flue gas desulfurization, denitrification, and dust removal in waste-to-energy plants, as provided in Examples 1-4 and Comparative Examples 1-5, is used to treat flue gas, particulate matter, and NOx generated by waste-to-energy plants. x The study investigated the synergistic removal efficiency of multiple pollutants, including dioxins, and their influencing factors. The parameters of the simulated flue gas from the outlet of a waste incineration boiler are shown in Table 1. The desulfurization efficiency, denitrification efficiency, dust removal efficiency, dioxin removal efficiency, and ammonia escape rate were tested, and the test results are shown in Table 2.
[0060] Table 1
[0061] The test results are shown in Table 2: Table 2
[0062] As shown in Table 2, the desulfurization, denitrification, and dust removal processes for flue gas in waste-to-energy plants described in Examples 1-4 exhibit excellent removal efficiency for all pollutants. This indicates that the process of the present invention, through the combination of circulating fluidized bed flue gas desulfurization and integrated dust and nitrogen removal devices, can achieve efficient and stable synergistic purification under the complex flue gas conditions of waste incineration, meeting low emission requirements.
[0063] Combining Comparative Example 1 and Example 1, it can be seen that the ceramic fiber catalytic filter tube used in Comparative Example 1 was not coated with a waterproof coating. Therefore, the ceramic fiber filter tube and catalyst are susceptible to corrosion by water vapor and acidic gases, resulting in a decrease in denitrification efficiency and dioxin removal rate, and an increase in ammonia slip rate. Combining Comparative Examples 2 and 3 with Example 1, it can be seen that the catalyst in Comparative Example 2 is not doped with V or Ce, therefore its resistance to SO2 is poor, and MnO... x The catalyst in Comparative Example 3 is susceptible to poisoning, leading to a decrease in denitrification efficiency. The catalyst in Comparative Example 3 lacks Ce doping and therefore lacks the acidic site enhancement effect of CeO2, resulting in a decrease in denitrification efficiency. Combining Comparative Examples 4 and 5 with Example 1, it can be seen that temperatures below or above the optimal activity temperature affect the catalytic activity of the catalyst, thus causing a decrease in denitrification efficiency.
[0064] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.
[0065] 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 process for flue gas desulfurization, denitrification, and dust removal in waste incineration power plants, characterized in that, Includes the following steps: Step 1: The flue gas from the waste incineration boiler outlet is introduced into a circulating fluidized bed reactor for desulfurization treatment. After the desulfurization reaction, the gas-solid mixture is separated by a gas-solid separator, and the desulfurized flue gas is obtained. Step 2: The temperature of the flue gas after desulfurization is adjusted by a burner, and then introduced into an integrated dust and nitrogen removal device with ceramic fiber catalytic filter tubes inside. While filtering dust, selective catalytic reduction denitrification reaction is carried out on the surface and inside of the filter tubes to obtain flue gas after denitrification and dust removal. Step 3: The flue gas after denitrification and dust removal is drawn out and discharged by an induced draft fan.
2. The process for flue gas desulfurization, denitrification, and dust removal in a waste incineration power plant according to claim 1, characterized in that, In step 1, the sulfur content of the flue gas from the waste incineration boiler outlet is ≤800 mg / Nm³. 3 .
3. The process for flue gas desulfurization, denitrification, and dust removal in a waste incineration power plant according to claim 1, characterized in that, In step 2, the burner adjusts the temperature of the flue gas after desulfurization to 280-320℃.
4. The process for flue gas desulfurization, denitrification, and dust removal in a waste incineration power plant according to claim 1, characterized in that, The ceramic fiber catalytic filter tube includes a ceramic fiber filter tube, a catalyst, and a waterproof coating; the catalyst is uniformly loaded on the outer surface, inner surface, and wall of the ceramic fiber filter tube; the waterproofing agent is uniformly coated on the outer wall surface of the ceramic fiber filter tube to form a waterproof coating.
5. The process for flue gas desulfurization, denitrification, and dust removal in a waste incineration power plant according to claim 1, characterized in that, The catalyst in the ceramic fiber catalytic filter tube in step 2 is prepared through the following steps: Oxalic acid was added to deionized water, heated to 50–55 °C, and stirred until homogeneous. Then, MnC₂O₄·2H₂O, NH₄VO₃, and CeO₂ were added, and the mixture was stirred for 2–3 h. γ-Al₂O₃ was added, and the mixture was allowed to stand for 12–16 h for impregnation. After impregnation, the pH was adjusted to 7.8–8.0 with ammonia water, and the mixture was stirred for another 2–3 h. The mixture was then dried in an oven at 105 °C and subsequently calcined at 450–550 °C for 5–6 h to obtain the catalyst.
6. The process for flue gas desulfurization, denitrification, and dust removal in a waste incineration power plant according to claim 5, characterized in that, The ratio of oxalic acid, deionized water, MnC2O4·2H2O, NH4VO3, CeO2, and γ-Al2O3 is 3.9–4.0 g: 30 mL: 2.7–2.8 g: 1.2–1.3 g: 0.50–0.55 g: 10.5 g.
7. The process for flue gas desulfurization, denitrification, and dust removal in a waste incineration power plant according to claim 1, characterized in that, The waterproofing agent in the ceramic fiber catalytic filter tube comprises the following raw materials in parts by weight: 5-15 parts of methyl silicone resin, 2-8 parts of inorganic binder, 1-3 parts of silane coupling agent KH-560, 2-5 parts of fumed nano silica, 30-50 parts of anhydrous ethanol, and 40-60 parts of water.
8. The process for flue gas desulfurization, denitrification, and dust removal in a waste incineration power plant according to claim 7, characterized in that, The inorganic binder is at least one of aluminum sol and silica sol.
9. The process for flue gas desulfurization, denitrification, and dust removal in a waste incineration power plant according to claim 1, characterized in that, The ceramic fiber catalytic filter tube in step 2 is prepared through the following steps: The ceramic fiber filter tube is impregnated with a catalyst-containing solution, dried at 120°C and calcined at 350-450°C to obtain a catalyst-loaded ceramic fiber filter tube; then a waterproofing agent is sprayed onto the outer surface of the ceramic fiber filter tube, and the thickness of the waterproof coating is controlled to obtain a ceramic fiber catalytic filter tube.
10. The process for flue gas desulfurization, denitrification, and dust removal in a waste incineration power plant according to claim 1, characterized in that, The thickness of the waterproof coating should be controlled between 15 and 25 μm.