A dual-function catalyst for removing dust and carbon and a preparation method thereof

Abstract

The application discloses a kind of dual-function catalysts of dust removal and decarburization, it is characterized in that: the catalyst is double-layer structure, including core layer and the outer membrane layer of coating in the outer surface of core layer;Wherein, the core layer includes Ni, Si is Ni-Si-based metal compound;The outer membrane layer is Ni-Cu-based alloy membrane, additionally optionally including or not including any one or more elements in Fe, Mn, Co.The application provides catalyst decarburization function layer with Ni-Si-based metal compound and Ni-Cu-based alloy membrane dust removal function layer are combined, realize the integration of dust removal, decarburization, and have good mechanical strength, high temperature resistance, thermal shock resistance, corrosion resistance and the like, meet the ability of stable service under complex flue gas working condition.

Description

Technical Field

[0001] This invention relates to a catalyst and its preparation method, specifically to a dual-function catalyst for dust removal and decarbonization and its preparation method, belonging to the field of flue gas purification technology. Background Technology

[0002] To date, my country has basically established the world's largest clean coal power generation system, and the power industry has transformed into a "model student" in the control of coal-fired flue gas pollution in a short period of time. The proportion of flue gas pollutant emissions from non-power industries is becoming increasingly prominent. Currently, besides SO2 and NO... X Besides particulate matter and dioxins, CO emissions from non-power industries have also received widespread attention. Meanwhile, industrial dust is also a major contributor to flue gas emissions, and the combined emissions of industrial dust and CO have led to significant ecological and environmental problems. Currently, existing environmental protection processes combine dust removal and decarbonization, which can effectively remove dust and CO, but suffers from problems such as low dust removal precision, easy CO catalyst poisoning, large equipment footprint, and high heat loss during flue gas transmission.

[0003] In the field of industrial flue gas purification, dust removal technology is the most mature, commonly including mechanical dust removal such as gravity / inertial / centrifugal force, filtration dust removal such as bag filters / metal membrane filters / ceramic membrane filters, wet scrubbing dust removal, and electrostatic precipitators. Regarding CO removal from flue gas, apart from the chemical industry (such as polyolefin industry) where CO removal technology is relatively mature under sulfur-free, anhydrous, and low-CO flue gas conditions, CO in complex flue gas components containing water and sulfur, such as those from steel sintering and glass furnaces, is directly emitted with the flue gas due to the lack of corresponding treatment technologies, posing a significant threat to human health and the ecological environment.

[0004] However, in existing technologies, mechanical dust collectors have problems such as low processing efficiency and large equipment footprint for treating large volumes of flue gas; bag filter dust collectors have problems such as easy ablation and perforation of filter bags in high-temperature flue gas and bag clogging in low-temperature flue gas; metal membrane dust collectors have problems such as easy corrosion; ceramic membrane dust collectors have problems such as large weight and poor machinability; wet scrubbing dust collectors have problems such as large water consumption, secondary pollution, and large flue gas temperature loss; and electrostatic precipitators have problems such as high energy consumption and stringent requirements for flue gas temperature.

[0005] Meanwhile, in terms of CO removal, a large number of catalyst systems under research and those used in small-scale commercial applications under simple flue gas atmospheres such as anhydrous sulfur are mainly noble metal Pd, Pt, Au and non-noble metal Mn, Cu, Fe catalyst systems. Noble metal catalysts have the problem of high material cost, while non-noble metal catalysts have problems such as water and sulfur inhibition and easy poisoning. Neither of them can meet the requirements for efficient and stable CO removal in complex flue gas environments such as steel sintering and glass furnaces.

[0006] In addition, traditional flue gas environmental protection processes usually involve dust removal first, followed by CO removal through a flue. The flue gas is transported within the flue. On the one hand, when the flue temperature is high, the flue material and seals are required to have good temperature resistance. On the other hand, heat loss is inevitable during flue gas transport, and the heat carried by the flue gas cannot be directly applied to the decarbonization process. Summary of the Invention

[0007] In view of the lack of corresponding treatment technology for CO in the existing technology, CO is directly emitted with flue gas. Existing CO catalysts are difficult to meet the requirements of efficient and stable CO removal in complex flue gas environments such as steel sintering and glass furnaces. Dust removal devices have problems such as low treatment efficiency, easy ablation and perforation, and secondary pollution. This invention proposes a dual-function catalyst for dust removal and decarbonization and its preparation method. The catalyst has a double-layer structure, which realizes high-precision dust filtration, direct utilization of flue gas heat, and efficient CO removal.

[0008] According to a first embodiment of the present invention, a dual-function catalyst for dust removal and decarbonization is provided.

[0009] A bifunctional catalyst for dust removal and decarbonization, the catalyst having a bilayer structure, including a core layer and an outer film layer coating the outer surface of the core layer; wherein, the core layer comprises Ni and Si as Ni-Si based metal compounds; the outer film layer is a Ni-Cu based alloy film, and optionally includes or excludes one or more elements selected from Fe, Mn, and Co.

[0010] Preferably, the general structural formula of the Ni-Si based metal compound is: Ni x Si y Where x ranges from 1 to 31, and y ranges from 1 to 12.

[0011] Preferably, the general structural formula of the outer Ni-Cu based alloy is: Ni m Cu n Where m ranges from 1 to 3, and n ranges from 1 to 3.

[0012] Preferably, the general structural formula of the kernel layer is Ni. x Si y A z Where A is any one or more of Ce, Fe, Mn, Cu, and Co; x ranges from 1 to 31, y ranges from 1 to 12, and z ranges from 0 to 5.

[0013] Preferably, the outer film layer has the general structural formula Ni. m Cu n B wWherein, B is any one or more of Fe, Mn, and Co; m ranges from 1 to 3, n ranges from 1 to 3, and w ranges from 0 to 0.6.

[0014] Preferably, the core layer has a porous structure with a pore size of 15–70 μm, more preferably 25–60 μm, and even more preferably 30–50 μm.

[0015] Preferably, the thickness of the core layer is 2-12 mm, more preferably 3-10 mm, and even more preferably 5-8 mm.

[0016] Preferably, the outer membrane layer has a porous structure with a pore size of 1–8 μm, more preferably 2–6 μm, and even more preferably 3–5 μm.

[0017] Preferably, the thickness of the outer film layer is 0.1 to 1.2 mm, more preferably 0.2 to 1.0 mm, and even more preferably 0.3 to 0.8 mm.

[0018] According to a second embodiment of the present invention, a method for preparing a dual-functional catalyst for dust removal and decarbonization is provided.

[0019] A method for preparing a bifunctional catalyst for dust removal and decarbonization, the method comprising the following steps:

[0020] 1) Mix the elemental Ni, elemental Si, and elemental Si, which may or may not include any one or more of Ce, Fe, Mn, Cu, and Co. After mixing, perform pre-reduction, add a granulating agent, dry and press to form a core layer green body. Sinter the obtained core layer green body to obtain the core layer.

[0021] 2) Mix elemental Ni, elemental Cu, and elemental Cu (optionally including or excluding Fe, Mn, Co) with auxiliary materials to obtain a slurry to be coated; immerse the core layer obtained in step 1) in a reaction vessel containing the slurry, pull it out to obtain a surface-coated core layer, and then dry and sinter the surface-coated core layer to obtain a dual-function catalyst for dust removal and decarbonization.

[0022] Preferably, the mass ratio of the elemental Ni, elemental Si, and other elements in step 1) is 70-85:11-20:2-8, and more preferably 77-83:13-17:3-7.

[0023] Preferably, the mixing method in step 1) is dry mixing.

[0024] Preferably, the ball-to-material ratio in the mixing process described in step 1) is 5 to 15:1, and more preferably 8 to 12:1.

[0025] Preferably, the mixing time in step 1) is 12 to 48 hours, more preferably 20 to 30 hours.

[0026] Preferably, the reduction atmosphere in step 1) is a CO or H2 atmosphere.

[0027] The reduction temperature in step 1) is 300–500°C, preferably 350–450°C.

[0028] Preferably, the reduction time in step 1) is 1 to 3 hours, more preferably 1.5 to 2.5 hours.

[0029] Preferably, the granulating agent in step 1) includes polyvinyl butyral and alcohol; preferably, the amount of polyvinyl butyral added is 2% to 10% of the material mass; and the amount of alcohol added is 6% to 30% of the material mass.

[0030] Preferably, the kernel layer described in step 1) is a plate-like or tubular structure.

[0031] Preferably, the sintering temperature in step 1) is 700–900°C, and more preferably 750–850°C.

[0032] Preferably, the sintering time in step 1) is 2 to 4 hours.

[0033] Preferably, the excipients in step 2) are PVB, silica sol, and alcohol; preferably, the mass ratio of elemental Ni powder, elemental Cu powder, and elemental powder of any one or more elements selected from Fe, Mn, and Co, PVB, silica sol, and alcohol is 20-40:5-15:2-8:2-8:10-20:30-50, and more preferably 25-35:7-13:4-6:3-7:13-17:35-45.

[0034] Preferably, the number of lifting strokes in step 2) is 1 to 8, more preferably 3 to 5.

[0035] Preferably, the sintering temperature in step 2) is 600–1000°C, and more preferably 700–900°C.

[0036] Preferably, the sintering time in step 2) is 2 to 4 hours.

[0037] Preferably, the method further includes step 1a) between step 1) and step 2): performing a purge and restoration preprocessing on the obtained kernel layer.

[0038] Preferably, the method further includes: 3) pre-oxidizing and calcining the dust removal and decarbonization bifunctional catalyst to obtain a pre-activated dust removal and decarbonization bifunctional catalyst.

[0039] Preferably, the purging in step 1a) involves purging the surface of the core layer material with high-pressure gas, and more preferably, high-pressure N2 is used for purging.

[0040] Preferably, the reduction in step 1a) involves placing the core layer material in a CO or H2 atmosphere for reduction.

[0041] Preferably, the reduction temperature in step 1a) is 300–500°C, and more preferably 350–450°C.

[0042] Preferably, the reduction time in step 1a) is 1 to 3 hours, more preferably 1.5 to 2.5 hours.

[0043] Preferably, the pre-oxidation in step 3) involves placing the dust removal and decarbonization bifunctional catalyst in the air.

[0044] Preferably, the pre-oxidation time in step 3) is 0.5 to 4 hours.

[0045] Preferably, the calcination temperature in step 3) is 400–800°C, and more preferably 500–700°C.

[0046] Preferably, the calcination time in step 3) is 2 to 4 hours.

[0047] Preferably, step 1) specifically involves: dry mixing elemental Ni powder, elemental Si powder, and elemental powders of any one or more elements selected from Ce, Fe, Mn, Cu, and Co at a mass ratio of 60–90:8–25:0.5–10 (preferably 70–85:11–20:2–8, more preferably 77–83:13–17:3–7), wherein the ball-to-material ratio of the dry mixture is 5–15:1 (preferably 8–12:1), and the dry mixing time is 12–15 minutes. After mixing for 48 hours (preferably 20-30 hours), the mixture is placed in a CO or H2 reducing atmosphere at 300-500℃ (preferably 350-450℃) for 1-3 hours (preferably 1.5-2.5 hours) and polyvinyl butyral and alcohol are added. The mixture is then dried and pressed into a plate-shaped or tubular core layer green body. The core layer green body is then sintered at 700-900℃ (preferably 750-850℃) for 2-4 hours (preferably 2-3 hours) to obtain the core layer raw material.

[0048] Preferably, step 2) specifically involves mixing elemental Ni powder, elemental Cu powder, and elemental powders of any one or more elements selected from Fe, Mn, and Co, PVB, silica sol, and alcohol in a mass ratio of 20–40:5–15:2–8:2–8:10–20:30–50 (preferably 25–35:7–13:4–6:3–7:13–17:35–45) to obtain a slurry to be coated. The core layer raw material obtained in step 1) is then immersed in a reaction vessel containing the slurry and pulled up 1–8 times (preferably 3–5 times). After drying, the mixture is sintered at 600–1000℃ (preferably 700–900℃) for 2–4 hours (preferably 2–3 hours) to obtain a dual-function catalyst for dust removal and decarbonization.

[0049] In this invention, a core layer of a catalyst is formed based on a Ni-Si-based metal compound, with or without the addition of one or more elements selected from Ce, Fe, Mn, Cu, and Co. Simultaneously, an outer film layer is formed on the outer surface of the core layer, based on a Ni-Cu-based alloy film, with or without the addition of one or more elements selected from Fe, Mn, and Co. x Si y And preferably Ni x Si y A z The general structural formula of the outer film layer Ni-Cu based alloy is Ni m Cu n And preferably Ni m Cu n B w This catalyst effectively enhances its adaptability to complex industrial flue gases and improves catalytic efficiency. The catalyst consists of an outer film layer for dust removal and a core layer for decarbonization, both possessing excellent mechanical strength, high-temperature resistance, thermal shock resistance, and corrosion resistance. Furthermore, as an intermetallic compound system, it exhibits excellent resistance to acid, alkali, and water corrosion, in addition to high-temperature resistance, enabling stable operation in complex industrial flue gas atmospheres across various fields. Simultaneously, the dust removal and CO removal processes are organically combined, achieving simultaneous and direct CO removal after efficient dust interception. This avoids heat loss during the dust removal-transfer-decarbonization process and significantly reduces the equipment's footprint.

[0050] In this invention, the pore sizes and membrane thicknesses of the core layer and outer membrane layer are defined. The outer membrane layer (i.e., the dust removal layer) has a smaller pore size and thickness, used for precise dust removal from flue gas, with a filtration accuracy of approximately 1 μm. It effectively removes alkali metals, alkaline earth metals, and heavy metals from the dust, effectively preventing harmful elements in the dust from poisoning the subsequent core layer and affecting its decarbonization function, thus creating favorable conditions for efficient decarbonization. The core layer (i.e., the decarbonization layer) has a larger pore size and thickness, ensuring structural strength while allowing flue gas to pass through quickly, reducing flue gas flow resistance.

[0051] In this invention, the prerequisite for realizing the dual-functional catalyst for dust removal and decarbonization is the stable bonding between the Ni-Cu alloy outer film layer and the Ni-Si based metal core layer. This invention employs a vacuum sintering reaction synthesis. First, a Ni-Si based metal porous material decarbonization functional layer is prepared. Then, a slurry containing elements such as Ni and Cu is prepared. The slurry is coated onto the Ni-Si based metal porous material decarbonization functional layer and vacuum sintered, ultimately yielding the dual-functional catalyst for dust removal and decarbonization. This two-step vacuum sintering method achieves a good metallurgical bond between the Ni-Si based decarbonization functional layer and the Ni-Cu dust removal functional layer, resulting in a more complete chemical reaction, richer pores, more uniform material structure, and more stable material use, realizing an integrated combination of dust removal and CO removal.

[0052] In this invention, the two pre-reduction processes in steps 1) and 1a) strictly ensure the reaction process of the elemental powder and the coating process of the outer film layer, ensuring that the micro-oxidized parts during sintering are reduced, thereby improving the catalytic efficiency and stability of the catalyst. Furthermore, the pre-oxidation treatment of the coated catalyst allows oxygen atoms to enter the catalyst surface. This pre-oxidation and calcination process activates the active sites on the catalyst surface in advance, improving the material's corrosion resistance and increasing the catalyst's lifespan and catalytic stability.

[0053] In this invention, the raw materials of the dust removal and decarbonization bifunctional catalyst are common non-precious metal elements such as Ni, Si, and Cu. The preparation process adopted is common coating, powder metallurgy sintering, etc., which has the advantages of readily available materials, simple preparation, easy mass production, controllable product quality, and easy adjustment of product parameters.

[0054] In this invention, the metal compound material system and the metallurgical bonding of the inner and outer layers ensure excellent mechanical strength. After dust is intercepted and deposited in the dust removal layer, it can be removed by high-pressure air backflushing or water washing, resulting in simple equipment maintenance and a long service life. In addition, the Ni-Cu alloy porous membrane dust collector has a wide acceptable range of flue gas temperature, avoiding the risks of damage and bag ablation perforation of traditional electrostatic precipitators under high-temperature environments, and the risk of flue gas condensation corroding electrostatic precipitators and causing bag clogging under low-temperature environments.

[0055] In this invention, the raw materials and preparation process have a wide range of adjustment. By adjusting the particle size of the raw material powder, the ratio of powder and additives, and changing the coating process and sintering process, the chemical composition and physical structure parameters of the material can be controlled and adjusted, making it suitable for various types of flue gas.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] 1. The present invention provides a dual-function catalyst for dust removal and decarbonization, which combines a Ni-Si-based metal compound decarbonization functional layer with a Ni-Cu-based alloy film dust removal functional layer to achieve an integrated combination of dust removal and CO removal. It also has good mechanical strength, high temperature resistance, thermal shock resistance, corrosion resistance and other properties, and meets the requirements for stable operation under complex flue gas conditions.

[0058] 2. The dust removal and decarbonization bifunctional catalyst provided by the present invention strictly limits the mass ratio of each substance in the decarbonization functional layer and the dust removal functional layer, so that there are sufficient active sites in the catalyst and high catalytic efficiency, while preventing the catalyst activity and stability from decreasing and affecting the decarbonization efficiency.

[0059] 3. The present invention provides a method for preparing a dual-function catalyst for dust removal and decarbonization. The materials are readily available, the preparation is simple, it is easy to mass-produce, the product quality is controllable, and the product parameters are easy to adjust. In addition, by adjusting the particle size of the raw material powder, the ratio of powder and additives, and changing the coating process and sintering process, the chemical composition and physical structure parameters of the material can be controlled and adjusted, and the catalyst has strong applicability. Attached Figure Description

[0060] Figure 1 This invention provides a schematic diagram of the structure of a dual-function catalyst for dust removal and decarbonization. Detailed Implementation

[0061] The technical solution of the present invention will be illustrated below with examples. The scope of protection sought by the present invention includes, but is not limited to, the following embodiments.

[0062] According to a first embodiment of the present invention, a dual-function catalyst for dust removal and decarbonization is provided.

[0063] A bifunctional catalyst for dust removal and decarbonization, the catalyst having a bilayer structure, including a core layer and an outer film layer coating the outer surface of the core layer; wherein, the core layer comprises Ni and Si as Ni-Si based metal compounds; the outer film layer is a Ni-Cu based alloy film, and optionally includes or excludes one or more elements selected from Fe, Mn, and Co.

[0064] Preferably, the general structural formula of the Ni-Si based metal compound is: Ni x Siy Where x ranges from 1 to 31, and y ranges from 1 to 12.

[0065] Preferably, the general structural formula of the outer Ni-Cu based alloy is: Ni m Cu n Where m ranges from 1 to 3, and n ranges from 1 to 3.

[0066] Preferably, the general structural formula of the kernel layer is Ni. x Si y A z Where A is any one or more of Ce, Fe, Mn, Cu, and Co; x ranges from 1 to 31, y ranges from 1 to 12, and z ranges from 0 to 5.

[0067] Preferably, the outer film layer has the general structural formula Ni. m Cu n B w Wherein, B is any one or more of Fe, Mn, and Co; m ranges from 1 to 3, n ranges from 1 to 3, and w ranges from 0 to 0.6.

[0068] Preferably, the core layer has a porous structure with a pore size of 15–70 μm, more preferably 25–60 μm, and even more preferably 30–50 μm.

[0069] Preferably, the thickness of the core layer is 2-12 mm, more preferably 3-10 mm, and even more preferably 5-8 mm.

[0070] Preferably, the outer membrane layer has a porous structure with a pore size of 1–8 μm, more preferably 2–6 μm, and even more preferably 3–5 μm.

[0071] Preferably, the thickness of the outer film layer is 0.1 to 1.2 mm, more preferably 0.2 to 1.0 mm, and even more preferably 0.3 to 0.8 mm.

[0072] According to a second embodiment of the present invention, a method for preparing a dual-functional catalyst for dust removal and decarbonization is provided.

[0073] A method for preparing a bifunctional catalyst for dust removal and decarbonization, the method comprising the following steps:

[0074] 1) Mix the elemental Ni, elemental Si, and elemental Si, which may or may not include any one or more of Ce, Fe, Mn, Cu, and Co. After mixing, perform pre-reduction, add a granulating agent, dry and press to form a core layer green body. Sinter the obtained core layer green body to obtain the core layer.

[0075] 2) Mix elemental Ni, elemental Cu, and elemental Cu (optionally including or excluding Fe, Mn, Co) with auxiliary materials to obtain a slurry to be coated; immerse the core layer obtained in step 1) in a reaction vessel containing the slurry, pull it out to obtain a surface-coated core layer, and then dry and sinter the surface-coated core layer to obtain a dual-function catalyst for dust removal and decarbonization.

[0076] Preferably, the mass ratio of the elemental Ni, elemental Si, and other elements in step 1) is 70-85:11-20:2-8, and more preferably 77-83:13-17:3-7.

[0077] Preferably, the mixing method in step 1) is dry mixing.

[0078] Preferably, the ball-to-material ratio in the mixing process described in step 1) is 5 to 15:1, and more preferably 8 to 12:1.

[0079] Preferably, the mixing time in step 1) is 12 to 48 hours, more preferably 20 to 30 hours.

[0080] Preferably, the reduction atmosphere in step 1) is a CO or H2 atmosphere.

[0081] The reduction temperature in step 1) is 300–500°C, preferably 350–450°C.

[0082] Preferably, the reduction time in step 1) is 1 to 3 hours, more preferably 1.5 to 2.5 hours.

[0083] Preferably, the granulating agent in step 1) includes polyvinyl butyral and alcohol; preferably, the amount of polyvinyl butyral added is 2% to 10% of the material mass; and the amount of alcohol added is 6% to 30% of the material mass.

[0084] Preferably, the kernel layer described in step 1) is a plate-like or tubular structure.

[0085] Preferably, the sintering temperature in step 1) is 700–900°C, and more preferably 750–850°C.

[0086] Preferably, the sintering time in step 1) is 2 to 4 hours.

[0087] Preferably, the excipients in step 2) are PVB, silica sol, and alcohol; preferably, the mass ratio of elemental Ni powder, elemental Cu powder, and elemental powder of any one or more elements selected from Fe, Mn, and Co, PVB, silica sol, and alcohol is 20-40:5-15:2-8:2-8:10-20:30-50, and more preferably 25-35:7-13:4-6:3-7:13-17:35-45.

[0088] Preferably, the number of lifting strokes in step 2) is 1 to 8, more preferably 3 to 5.

[0089] Preferably, the sintering temperature in step 2) is 600–1000°C, and more preferably 700–900°C.

[0090] Preferably, the sintering time in step 2) is 2 to 4 hours.

[0091] Preferably, the method further includes step 1a) between step 1) and step 2): performing a purge and restoration preprocessing on the obtained kernel layer.

[0092] Preferably, the method further includes: 3) pre-oxidizing and calcining the dust removal and decarbonization bifunctional catalyst to obtain a pre-activated dust removal and decarbonization bifunctional catalyst.

[0093] Preferably, the purging in step 1a) involves purging the surface of the core layer material with high-pressure gas, and more preferably, high-pressure N2 is used for purging.

[0094] Preferably, the reduction in step 1a) involves placing the core layer material in a CO or H2 atmosphere for reduction.

[0095] Preferably, the reduction temperature in step 1a) is 300–500°C, and more preferably 350–450°C.

[0096] Preferably, the reduction time in step 1a) is 1 to 3 hours, more preferably 1.5 to 2.5 hours.

[0097] Preferably, the pre-oxidation in step 3) involves placing the dust removal and decarbonization bifunctional catalyst in the air.

[0098] Preferably, the pre-oxidation time in step 3) is 0.5 to 4 hours.

[0099] Preferably, the calcination temperature in step 3) is 400–800°C, and more preferably 500–700°C.

[0100] Preferably, the calcination time in step 3) is 2 to 4 hours.

[0101] Preferably, step 1) specifically involves: dry mixing elemental Ni powder, elemental Si powder, and elemental powders of any one or more elements selected from Ce, Fe, Mn, Cu, and Co at a mass ratio of 60–90:8–25:0.5–10 (preferably 70–85:11–20:2–8, more preferably 77–83:13–17:3–7), wherein the ball-to-material ratio of the dry mixture is 5–15:1 (preferably 8–12:1), and the dry mixing time is 12–15 minutes. After mixing for 48 hours (preferably 20-30 hours), the mixture is placed in a CO or H2 reducing atmosphere at 300-500℃ (preferably 350-450℃) for 1-3 hours (preferably 1.5-2.5 hours) and polyvinyl butyral and alcohol are added. The mixture is then dried and pressed into a plate-shaped or tubular core layer green body. The core layer green body is then sintered at 700-900℃ (preferably 750-850℃) for 2-4 hours (preferably 2-3 hours) to obtain the core layer raw material.

[0102] Preferably, step 2) specifically involves mixing elemental Ni powder, elemental Cu powder, and elemental powders of any one or more elements selected from Fe, Mn, and Co, PVB, silica sol, and alcohol in a mass ratio of 20–40:5–15:2–8:2–8:10–20:30–50 (preferably 25–35:7–13:4–6:3–7:13–17:35–45) to obtain a slurry to be coated. The core layer raw material obtained in step 1) is then immersed in a reaction vessel containing the slurry and pulled up 1–8 times (preferably 3–5 times). After drying, the mixture is sintered at 600–1000℃ (preferably 700–900℃) for 2–4 hours (preferably 2–3 hours) to obtain a dual-function catalyst for dust removal and decarbonization.

[0103] Example 1

[0104] 1) Dry mix 79g Ni powder and 14g Si powder for 25h. The ball-to-powder ratio of the dry mix is ​​10:1. After mixing, place it in a CO reducing atmosphere at 400℃ for 2h. Then add 5g polyvinyl butyral and 15g alcohol. After drying, press it into a plate-shaped core layer green body. Sinter the core layer green body at 800℃ for 3h to obtain the core layer raw material.

[0105] 1a) The obtained core layer material was surface-purged with high-pressure N2 and then reduced in a CO atmosphere at 400°C for 2 hours.

[0106] 2) Mix 29g Ni powder, 9g Cu powder, 5g PVB, 15g silica sol and 40g alcohol. After mixing, a slurry to be coated is obtained. Immerse the core layer material obtained in step 1) in a reaction vessel containing the slurry, lift it 5 times, dry it and sinter it at 800℃ for 2 hours to obtain a dust removal and decarbonization bifunctional catalyst.

[0107] 3) Place the obtained dust removal and decarbonization bifunctional catalyst in air for 1.5 hours, and then calcine it at 600℃ for 3 hours to obtain a pre-activated dust removal and decarbonization bifunctional catalyst.

[0108] Example 2

[0109] 1) Dry mix 80g Ni powder and 15g Si powder for 25h. The ball-to-powder ratio of the dry mix is ​​9:1. After mixing, place it in a CO reducing atmosphere at 420℃ for 2.3h. Then add 6g polyvinyl butyral and 18g alcohol. After drying, press it into a plate-shaped core layer green body. Sinter the core layer green body at 820℃ for 3h to obtain the core layer raw material.

[0110] 1a) The obtained core layer material was surface-purged with high-pressure N2 and then reduced in a CO atmosphere at 390°C for 1.8 h.

[0111] 2) Mix 31g Ni powder, 11g Cu powder, 6g PVB, 14g silica sol and 39g alcohol. After mixing, a slurry to be coated is obtained. Immerse the core layer raw material obtained in step 1) in a reaction vessel containing the slurry, lift it 3 times, dry it and sinter it at 820℃ for 2.5h to obtain a dust removal and decarbonization bifunctional catalyst.

[0112] 3) Place the obtained dust removal and decarbonization bifunctional catalyst in air for 1 hour, and then calcine it at 600℃ for 2 hours to obtain a pre-activated dust removal and decarbonization bifunctional catalyst.

[0113] Example 3

[0114] Repeat Example 1, except that 5g of Ce powder is added before the dry mixing step in step 1).

[0115] Example 4

[0116] Repeat Example 1, except that 5g of Mn powder is added before the dry mixing step in step 1).

[0117] Example 5

[0118] Repeat Example 1, except that 5g of Co powder is added before the dry mixing step in step 1).

[0119] Example 6

[0120] Repeat Example 1, except that 2.5g of Ce powder and 2.5g of Mn powder are added before the dry mixing step in step 1).

[0121] Example 7

[0122] Repeat Example 1, except that 2.5g of Ce powder and 2.5g of Fe powder are added before the dry mixing step in step 1).

[0123] Example 8

[0124] Repeat Example 7, except that 5g of Fe powder is added before the mixing step in step 2).

[0125] Example 9

[0126] Repeat Example 7, except that 5g of Mn powder is added before the mixing step in step 2).

[0127] Example 10

[0128] Repeat Example 7, except that 2.5g of Mn powder and 2.5g of Fe powder are added before the mixing step in step 2).

[0129] Example 11

[0130] Repeat Example 7, except that 2.5g of Fe powder and 2.5g of Co powder are added before the mixing step in step 2).

[0131] Using the same method as in Example 11, the amounts of Ni, Si, and other elements added in step 1) and the amounts of Ni, Cu, and other elements added in step 2) were adjusted to conduct parallel experiments, resulting in catalysts with different core layer and outer membrane layer compositions. See Table 1 for details.

[0132] Table 1

[0133]

[0134]

[0135]

[0136] Example 36

[0137] Repeat Example 11, except without step 1a).

[0138] Example 37

[0139] Repeat Example 11, except without step 3).

[0140] Example 38

[0141] Repeat Example 11, except that the amount of Ni powder added in step 1) is 65g.

[0142] Example 39

[0143] Repeat Example 11, except that the amount of Ni powder added in step 1) is 90g.

[0144] Example 40

[0145] Repeat Example 11, except that the amount of Si powder added in step 1) is 8g.

[0146] Example 41

[0147] Repeat Example 11, except that the amount of Si powder added in step 1) is 25g.

[0148] Example 42

[0149] Repeat Example 11, except that in step 1), the amount of Ce powder added is 0.5g and the amount of Fe powder added is 0.5g.

[0150] Example 43

[0151] Repeat Example 11, except that in step 1), the amount of Ce powder added is 5g and the amount of Fe powder added is 5g.

[0152] Example 44

[0153] Repeat Example 11, except that the amount of Ni powder added in step 2) is 15g.

[0154] Example 45

[0155] Repeat Example 11, except that the amount of Ni powder added in step 2) is 50g.

[0156] Example 46

[0157] Repeat Example 11, except that the amount of Cu powder added in step 2) is 2g.

[0158] Example 47

[0159] Repeat Example 11, except that the amount of Cu powder added in step 2) is 20g.

[0160] Example 48

[0161] Repeat Example 11, except that in step 2), the amount of Fe powder added is 0.5g and the amount of Co powder added is 0.5g.

[0162] Example 49

[0163] Repeat Example 11, except that in step 2), the amount of Fe powder added is 5g and the amount of Co powder added is 5g.

[0164] Comparative Example 1

[0165] 1) Dry mix 80g of Ni powder for 25h, with a ball-to-material ratio of 10:1. After mixing, place it in a CO reducing atmosphere at 400℃ for 2h, then add 4g of polyvinyl butyral and 13g of alcohol. After drying, press it into a plate-shaped core layer green body. Sinter the core layer green body at 800℃ for 3h to obtain the core layer raw material.

[0166] 1a) The obtained core layer material was surface-purged with high-pressure N2 and then reduced in a CO atmosphere at 400°C for 2 hours.

[0167] 2) Mix 31g Ni powder, 11g Cu powder, 2.5g Co powder, 5g PVB, 15g silica sol and 40g alcohol. After mixing, a slurry to be coated is obtained. Immerse the core layer raw material obtained in step 1) in a reaction vessel containing the slurry, lift it 5 times, dry it and sinter it at 800℃ for 2 hours to obtain a dust removal and decarbonization bifunctional catalyst.

[0168] 3) Place the obtained dust removal and decarbonization bifunctional catalyst in air for 1.5 hours, and then calcine it at 600℃ for 3 hours to obtain a pre-activated dust removal and decarbonization bifunctional catalyst.

[0169] Comparative Example 2

[0170] 1) Dry mix 15g of Si powder for 25h, with a ball-to-material ratio of 10:1. After mixing, place it in a CO reducing atmosphere at 400℃ for 2h. Then add 0.8g of polyvinyl butyral and 2.4g of alcohol. After drying, press it into a plate-shaped core layer green body. Sinter the core layer green body at 800℃ for 3h to obtain the core layer raw material.

[0171] 1a) The obtained core layer material was surface-purged with high-pressure N2 and then reduced in a CO atmosphere at 400°C for 2 hours.

[0172] 2) Mix 31g Ni powder, 11g Cu powder, 2.5g Co powder, 5g PVB, 15g silica sol and 40g alcohol. After mixing, a slurry to be coated is obtained. Immerse the core layer raw material obtained in step 1) in a reaction vessel containing the slurry, lift it 5 times, dry it and sinter it at 800℃ for 2 hours to obtain a dust removal and decarbonization bifunctional catalyst.

[0173] 3) Place the obtained dust removal and decarbonization bifunctional catalyst in air for 1.5 hours, and then calcine it at 600℃ for 3 hours to obtain a pre-activated dust removal and decarbonization bifunctional catalyst.

[0174] Comparative Example 3

[0175] 1) Dry mix 80g Ni powder, 15g Si powder, 2.5g Ce powder and 2.5g Fe powder for 25h. The ball-to-powder ratio of the dry mix is ​​10:1. After mixing, place it in a CO reducing atmosphere at 400℃ for 2h. Then add 5g polyvinyl butyral and 15g alcohol. After drying, press it into a plate-shaped core layer green body. Sinter the core layer green body at 800℃ for 3h to obtain the core layer raw material.

[0176] 1a) The obtained core layer material was surface-purged with high-pressure N2 and then reduced in a CO atmosphere at 400°C for 2 hours.

[0177] 2) Mix 42g Ni powder, 5g PVB, 15g silica sol and 40g alcohol. After mixing, a slurry to be coated is obtained. Immerse the core layer raw material obtained in step 1) in a reaction vessel containing the slurry, lift it 5 times, dry it and sinter it at 800℃ for 2 hours to obtain a dust removal and decarbonization bifunctional catalyst.

[0178] 3) Place the obtained dust removal and decarbonization bifunctional catalyst in air for 1.5 hours, and then calcine it at 600℃ for 3 hours to obtain a pre-activated dust removal and decarbonization bifunctional catalyst.

[0179] Comparative Example 4

[0180] 1) Dry mix 80g Ni powder, 15g Si powder, 2.5g Ce powder and 2.5g Fe powder for 25h. The ball-to-powder ratio of the dry mix is ​​10:1. After mixing, place it in a CO reducing atmosphere at 400℃ for 2h. Then add 5g polyvinyl butyral and 15g alcohol. After drying, press it into a plate-shaped core layer green body. Sinter the core layer green body at 800℃ for 3h to obtain the core layer raw material.

[0181] 1a) The obtained core layer material was surface-purged with high-pressure N2 and then reduced in a CO atmosphere at 400°C for 2 hours.

[0182] 2) Mix 42g Cu powder, 5g PVB, 15g silica sol and 40g alcohol. After mixing, a slurry to be coated is obtained. Immerse the core layer material obtained in step 1) in a reaction vessel containing the slurry, lift it 5 times, dry it and sinter it at 800℃ for 2 hours to obtain a dust removal and decarbonization bifunctional catalyst.

[0183] 3) Place the obtained dust removal and decarbonization bifunctional catalyst in air for 1.5 hours, and then calcine it at 600℃ for 3 hours to obtain a pre-activated dust removal and decarbonization bifunctional catalyst.

[0184] Comparative Example 5

[0185] 1) Dry mix 79g Ni powder and 14g Si powder for 25h. The ball-to-powder ratio of the dry mix is ​​10:1. After mixing, place it in a CO reducing atmosphere at 400℃ for 2h. Then add 5g polyvinyl butyral and 15g alcohol. After drying, press it into a plate-shaped core layer green body. Sinter the core layer green body at 800℃ for 3h to obtain the core layer raw material.

[0186] 2) The core layer material obtained in step 1) was surface-purged with high-pressure N2 and then reduced in a CO atmosphere at 400°C for 2 hours. Afterward, it was placed in air for 1.5 hours and then calcined at 600°C for 3 hours to obtain the decarbonization catalyst.

[0187] 3) Place the decarbonization catalyst obtained in step 2) into a bag filter.

[0188] Comparative Example 6

[0189] Repeat Comparative Example 5, except that the decarbonization catalyst obtained in step 2) is placed in a metal filter membrane dust collector.

[0190] The catalysts prepared using Examples 1-50 and Comparative Examples 1-6 were suitable for use at 350°C and a dust concentration of 1045 mg / m³. 3 CO concentration 4267 mg / m³ 3 The flue gas was treated for dust removal and decarbonization, and the decarbonization rate and dust removal rate are shown in Table 2.

[0191] Table 2

[0192]

[0193]

[0194]

[0195] In addition, the catalysts prepared in Examples 1, 11, and Comparative Examples 1-6 were placed at a temperature of 330°C and a CO concentration of 4013 mg / m³. 3 Dust concentration 1603 mg / m³ 3 SO2 concentration 2046 mg / m³ 3 NO x Concentration 2661 mg / m³ 3 The dust removal and decarbonization were continuously carried out in flue gas with a humidity of 10.2%, and the dust removal and decarbonization rates of the catalyst were monitored after 0h, 24h, and 48h. The results are shown in Table 3.

[0196] Table 3

[0197]

[0198]

[0199] The above experiments show that the dust removal and decarbonization dual-function catalyst provided by the present invention can remove dust and carbon simultaneously, with high dust removal and decarbonization efficiency, and can maintain a good dust removal and decarbonization rate in complex environments such as high temperature and high acidity.

Claims

1. A dual-function catalyst for dust removal and decarbonization, characterized in that: The catalyst has a bilayer structure, comprising a core layer and an outer film layer coating the outer surface of the core layer. The core layer comprises Ni and Si as Ni-Si based metal compounds. The outer film layer is a Ni-Cu based alloy film, optionally including or excluding one or more elements selected from Fe, Mn, and Co. The core layer has a porous structure with a pore size of 15–70 μm and a thickness of 2–12 mm. The outer film layer also has a porous structure with a pore size of 1–8 μm and a thickness of 0.1–1.2 mm. The general structural formula of the core layer is Ni. x Si y A z Wherein, A is any one or more of Ce, Fe, Mn, Cu, and Co; x ranges from 1 to 31, y ranges from 1 to 12, and z ranges from 0 to 5; the general structural formula of the outer film layer is Ni. m Cu n B w Wherein, B is any one or more of Fe, Mn, and Co; m ranges from 1 to 3, n ranges from 1 to 3, and w ranges from 0 to 0.6; the outer membrane layer is a dust removal layer, and the inner core layer is a decarburization layer. The preparation method of the catalyst includes: 1) mixing elemental Ni, elemental Si, and elemental Si that may or may not include any one or more of Ce, Fe, Mn, Cu, and Co; performing pre-reduction after mixing; adding a granulating agent; drying and pressing to obtain a core layer green body; and sintering the obtained core layer green body to obtain the core layer. 2) Mix elemental Ni, elemental Cu, and elemental Cu (optionally including or excluding Fe, Mn, and Co) with auxiliary materials to obtain a slurry to be coated; immerse the core layer obtained in step 1) in a reaction vessel containing the slurry, pull it out to obtain a surface-coated core layer, and then dry and sinter the surface-coated core layer to obtain a dust removal and decarbonization bifunctional catalyst; the auxiliary materials are PVB, silica sol, and alcohol.

2. The catalyst according to claim 1, characterized in that: The pore size of the core layer is 25~60μm; and / or The thickness of the core layer is 3~10mm; and / or The outer membrane layer has a pore size of 2~6μm; and / or The thickness of the outer membrane layer is 0.2~1.0 mm.

3. The catalyst according to claim 2, characterized in that: The pore size of the core layer is 30~50μm; and / or The thickness of the core layer is 5-8 mm; and / or The outer membrane layer has a pore size of 3~5μm; and / or The thickness of the outer membrane layer is 0.3~0.8 mm.

4. A method for preparing the catalyst according to any one of claims 1-3, characterized in that: The method includes the following steps: 1) Mix the elemental Ni, elemental Si, and elemental Si, which may or may not include any one or more of Ce, Fe, Mn, Cu, and Co. After mixing, perform pre-reduction, add a granulating agent, dry and press to form a core layer green body. Sinter the obtained core layer green body to obtain the core layer. 2) Mix elemental Ni, elemental Cu, and elemental Cu (optionally including or excluding Fe, Mn, and Co) with auxiliary materials to obtain a slurry to be coated; immerse the core layer obtained in step 1) in a reaction vessel containing the slurry, pull it out to obtain a surface-coated core layer, and then dry and sinter the surface-coated core layer to obtain a dust removal and decarbonization bifunctional catalyst; the auxiliary materials are PVB, silica sol, and alcohol.

5. The method according to claim 4, characterized in that: In step 1), the mass ratio of elemental Ni, elemental Si, and other elements is 70-85:11-20:2-8; and / or Step 1) The mixing method is dry mixing; and / or Step 1) The ball-to-material ratio during the mixing process is 5~15:1; and / or The mixing time in step 1) is 12~48h; and / or Step 1) The pre-reduction atmosphere is a CO or H2 atmosphere; and / or Step 1) The pre-reduction temperature is 300~500℃; and / or Step 1) The pre-reduction time is 1~3 hours; and / or The granulating agent described in step 1) includes polyvinyl butyral and alcohol; and / or The kernel layer described in step 1) is a plate-like or tubular structure; and / or Step 1) The sintering temperature is 700~900℃; and / or Step 1) Sintering time is 2~4 hours.

6. The method according to claim 5, characterized in that: In step 1), the mass ratio of elemental Ni, elemental Si, and other elements is 77~83:13~17:3~7; and / or Step 1) The ball-to-material ratio during the mixing process is 8~12:1; and / or The mixing time in step 1) is 20-30 hours; and / or Step 1) The pre-reduction temperature is 350~450℃; and / or Step 1) The pre-reduction time is 1.5~2.5h; and / or The amount of polyvinyl butyral added is 2% to 10% of the material mass; the amount of alcohol added is 6% to 30% of the material mass; and / or Step 1) The sintering temperature is 750~850℃.

7. The method according to claim 4, characterized in that: Step 2) involves lifting 1 to 8 times; and / or Step 2) The sintering temperature is 600~1000℃; and / or The sintering time in step 2) is 2-4 hours.

8. The method according to claim 7, characterized in that: The mass ratio of elemental Ni powder, elemental Cu powder, and elemental powders of any one or more elements selected from Fe, Mn, and Co, PVB, silica sol, and alcohol is 20~40:5~15:2~8:2~8:10~20:30~50; and / or Step 2) Lift 3-5 times; and / or Step 2) The sintering temperature is 700~900℃.

9. The method according to claim 8, characterized in that: The mass ratio of elemental Ni powder, elemental Cu powder, and elemental powders of one or more elements in Fe, Mn, and Co, PVB, silica sol, and alcohol is 25~35:7~13:4~6:3~7:13~17:35~45.

10. The method according to claim 4, characterized in that: The method also includes step 1a) between step 1) and step 2): performing a purge and restoration preprocessing on the obtained kernel layer; and / or The method also includes: 3) pre-oxidizing and calcining the dust removal and decarbonization bifunctional catalyst to obtain a pre-activated dust removal and decarbonization bifunctional catalyst.

11. The method according to claim 10, characterized in that: Step 1a) refers to purging the surface of the core layer material using high-pressure gas; and / or Step 1a) The reduction is performed by placing the core layer material in a CO or H2 atmosphere for reduction; and / or The reduction temperature in step 1a) is 300~500℃; and / or The reduction time in step 1a) is 1~3 hours; and / or Step 3) The pre-oxidation involves placing the dust removal and decarbonization bifunctional catalyst in air; and / or Step 3) The pre-oxidation time is 0.2~4h; and / or Step 3) The calcination temperature is 400~800℃; and / or Step 3) The calcination time is 2-4 hours.

12. The method according to claim 11, characterized in that: The purging described in step 1a) is performed using high-pressure N2; and / or The reduction temperature in step 1a) is 350~450℃; and / or The reduction time in step 1a) is 1.5~2.5h; and / or Step 3) The calcination temperature is 500~700℃.

13. The method according to any one of claims 4-12, characterized in that: Step 1) specifically involves: dry mixing elemental Ni powder, elemental Si powder, and elemental powders of any one or more elements selected from Ce, Fe, Mn, Cu, and Co at a mass ratio of 60-90:8-25:0.5-10, with a ball-to-material ratio of 5-15:1, for 12-48 hours. After mixing, the mixture is placed in a CO or H2 reducing atmosphere at 300-500℃ for 1-3 hours for reduction, and polyvinyl butyral and alcohol are added. The mixture is then dried and pressed into a plate-like or tubular core layer green body. The core layer green body is sintered at 700-900℃ for 2-4 hours to obtain the core layer raw material; and / or Step 2) specifically involves mixing elemental Ni powder, elemental Cu powder, and elemental powders of any one or more elements from Fe, Mn, and Co, along with PVB, silica sol, and alcohol, in a mass ratio of 20-40:5-15:2-8:2-8:10-20:30-50 to obtain a slurry to be coated. The core layer material obtained in step 1) is then immersed in a reaction vessel containing the slurry, lifted 1-8 times, dried, and sintered at 600-1000℃ for 2-4 hours to obtain a dual-function catalyst for dust removal and decarbonization.

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