CN117225178A

CN117225178A - Waste incinerator flue gas treatment process

Info

Publication number: CN117225178A
Application number: CN202311066154.6A
Authority: CN
Inventors: 王海强; 吴忠标; 费晓琦; 高珊
Original assignee: Zhejiang University ZJU; Zhejiang Tianlan Environmental Protection Technology Co Ltd
Current assignee: Zhejiang University ZJU; Zhejiang Tianlan Environmental Protection Technology Co Ltd
Priority date: 2023-08-23
Filing date: 2023-08-23
Publication date: 2023-12-15

Abstract

The application discloses a waste incinerator flue gas treatment process, which uses a core-shell structure catalyst with inner and outer functional partitions to catalyze, oxidize and synchronously remove CO, non-methane total hydrocarbons and dioxin in the waste incinerator flue gas at one time; the core-shell structure catalyst with the inner and outer functional partitions comprises an inner core capable of removing CO and non-methane total hydrocarbons by catalytic oxidation and an outer shell capable of decomposing dioxin by catalytic oxidation; the inner core is a Co-M mixed oxide nano rod with a mesoporous structure, wherein M is at least one of La, ce and Pr; the shell is a N-HZSM-5 molecular sieve with a macroporous structure, wherein N is at least one of Pt, pd and Ru. The catalyst can well solve the problems of synchronous one-time catalytic removal of CO, non-methane total hydrocarbon, dioxin and other smoke pollutants and catalyst chlorine poisoning.

Description

Waste incinerator flue gas treatment process

Technical Field

The application relates to the technical field of complex flue gas treatment, in particular to a flue gas treatment process of a garbage incinerator.

Background

With urban development and population growth, urban household garbage amount steadily rises year by year, and at present, garbage disposal is widely applied to sanitary landfill, incineration and composting, wherein the harmless, decrement and recycling degree by an incineration method is the highest.

Although the incineration of refuse can avoid some pollution caused by landfill refuse, the refuse incineration process inevitably generates a large amount of gas pollutants, such as CO, VOCs, NO _x 、SO ₂ And dust, etc. Domestic garbage such as kitchen contains chloride ions with different concentrations, so that more toxic chlorine-containing organic matters (such as chlorobenzene, dioxin and the like) are generated, are difficult to treat, and easily cause huge environmental pollution. In the traditional pharmaceutical and chemical industry, because a large amount of chlorine-containing and chlorine-free organic solvents are used in the production process, the tail gas discharged by the traditional pharmaceutical and chemical industry also has the characteristic of mixing the chlorine-containing organic matters and the chlorine-free organic matters.

For combustible compounds such as CO, VOCs and chlorine-containing organic matters, the catalytic degradation technology is one of the preferred treatment technologies, is considered to be an effective means for treating the CO, the VOCs and the chlorine-containing organic matters, and is widely focused by domestic and foreign expert students. The method has the characteristics of low conversion temperature, high treatment efficiency, difficult secondary pollution generation and the like, and is one of the most effective terminal treatment technologies of a plurality of combustible gases.

Patent specification publication No. CN109772347B discloses a sulfur-tolerant CO catalytic combustion catalyst for catalytic cracking unit (FCC) production process and its preparation method, the catalyst contains copper-cerium-zirconium-magnesium composite oxide supported on alumina, the same asWhen the magnesium alloy is used, the heat stability auxiliary agent zirconium, the sulfur poisoning resistance auxiliary agent magnesium and the like are added. It has high CO catalytic combustion activity (CO conversion rate 100%), high hydrothermal stability and effective inhibition of NO in flue gas _x Is produced and has sulfur-resistant toxicity. However, the catalyst is only suitable for the FCC production process and does not have the synergistic treatment performance of other gaseous pollutants.

Patent specification with publication number of CN104549231B discloses a catalyst for catalyzing and degrading dioxin in waste incineration tail gas and a preparation method thereof. The catalyst takes carbon nano tube as a main carrier and VO _x 、WO _x 、MnO _x 、TiO ₂ The catalyst is prepared by adopting an extrusion molding method to prepare a honeycomb catalyst serving as a main active catalytic component, and then drying and activating. The catalyst is suitable for the catalytic cracking reaction of dioxin substances.

The patent specification with publication number of CN109126773B discloses a catalyst for purifying waste incineration flue gas, which takes vanadium pentoxide, platinum oxide and tungsten oxide as active components, gamma-alumina, titanium dioxide and carbon nano tubes as carriers, and one or more of manganese oxide, ferric oxide, copper oxide, tin oxide and cerium oxide as active auxiliary agents. The catalyst has the effects of decomposing dioxin and chlorobenzene compounds, and has the effects of denitration and sulfur resistance, and can be used for treating dioxin and NO at lower temperature _x Has excellent removing ability.

Patent specification publication No. CN113333015B discloses a chlorine-containing organic waste gas catalytic combustion catalyst with high carbon dioxide selectivity and a preparation method thereof. The catalyst takes an HZSM-5 molecular sieve as a carrier, and loaded copper oxide, niobium oxide and cerium oxide as active components, wherein the molar ratio of Cu to Nb to Ce is 0.25-0.75:0.5-1:0.25-1.5, niobium oxalate, copper nitrate and cerium nitrate are dissolved in deionized water, then the HZSM-5 molecular sieve is added, and the catalyst is dried after full impregnation and baked at 550 ℃ to obtain the chlorine-containing organic waste gas catalytic combustion catalyst with high carbon dioxide selectivity.

Therefore, the catalytic degradation technology is a treatment technology for efficiently treating combustible smoke pollutants such as CO, VOCs, dioxin and the like. However, most of the existing catalytic degradation processes are single objects or gaseous components of the same type, and the catalyst components for treating CO, VOCs and dioxin are quite different, so that the catalyst cannot be used universally.

The catalytic oxidation process of chlorine-containing VOCs such as dioxins can be roughly divided into three steps: (1) Pollutant molecules or fine particles adsorbing dioxin are intercepted on the surface of the catalyst, and are dissociated and dechlorinated (C-Cl bond is broken) to form intermediate species, HCl and Cl ₂ The method comprises the steps of carrying out a first treatment on the surface of the (2) The intermediate species are further oxidized by reactive oxygen species and the like to form CO ₂ And H ₂ O (3) dissociated HCl and Cl ₂ The chlorine species are removed from the catalyst surface. Noble metal loaded molecular sieve and other materials are used as catalyst for catalytic oxidation of chlorine-containing organic waste gas, and the catalytic degradation performance is excellent. Noble metal loaded molecular sieves possess rich acidic centers and can be used as adsorption and dechlorination sites for pollutants, however, the type of catalysts do not have the catalytic oxidation capability of CO and other VOCs, and in addition, the accumulation of chlorine-containing species and the accumulation of intermediate products on the acidic sites are easy to cause the poisoning of the catalysts. Co (Co) ₃ O ₄ The transition metal oxides have excellent redox properties and can achieve deep oxidation of CO, VOC and other carbonaceous intermediates. However, the transition metal oxide has strong adsorption capacity to chlorine species and reacts with chlorine species to form metal chloride, which results in serious catalyst chloridiong. Therefore, how to realize the catalytic degradation of the flue gas pollutants with different properties in different functional areas through the structural design of the catalyst is a great challenge for the flue gas containing various flue gas pollution components such as the current garbage incinerator.

Disclosure of Invention

Aiming at the technical problems and the defects existing in the field, the application provides a waste incinerator flue gas treatment process, which aims to solve the problem of synchronous one-time catalytic removal of flue gas pollutants such as CO, non-methane total hydrocarbons, dioxin and the like which are discharged in a large amount by the waste incinerator under the incomplete combustion condition. The traditional catalyst for removing dioxin in flue gas is mainly a vanadium-based catalyst, CO and non-methane total hydrocarbon generated by incomplete combustion of a garbage incinerator cannot be effectively degraded on the vanadium-based catalyst, meanwhile, adsorption and insufficient degradation of the CO and the non-methane total hydrocarbon on the surface of the catalyst can lead the catalyst to be rapidly deactivated due to surface carbon deposition, and meanwhile, the removal capability of the vanadium-based catalyst on dioxin is insufficient under the coexistence condition of other volatile organic compounds.

The technical scheme adopted by the application is as follows:

a kind of garbage incinerator flue gas treatment process, use the core-shell structure catalyst of the inner and outer functional partition to catalyze and oxidize and remove CO, non-methane total hydrocarbon and dioxin in the garbage incinerator flue gas synchronously once only;

the core-shell structure catalyst with the inner and outer functional partitions comprises an inner core capable of removing CO and non-methane total hydrocarbon by catalytic oxidation and an outer shell capable of decomposing dioxin by catalytic oxidation;

the inner core is a mesoporous Co-M mixed oxide nano rod (Co is Co ₃ O ₄ In the form of (a), wherein M is at least one of La, ce, pr;

the shell is a N-HZSM-5 molecular sieve with a macroporous structure, wherein N is at least one of Pt, pd and Ru.

Many absorption such as dioxin and polychlorinated biphenyl in the incineration flue gas are in the fine particles, and traditional catalyst can't be effective with fine particles contact, and interception efficiency is also not high, not only is not high to degradation efficiency such as dioxin, produces the poisoning moreover easily. In the core-shell structure catalyst with internal and external functional partitions, the N-HZSM-5 molecular sieve of the shell layer has a macroporous structure, so that the catalyst is suitable for interception and in-situ contact of fine particles, and meanwhile, the shell has rich acidic sites, interception and adsorption of dioxin and fracture of C-Cl can be efficiently completed on the catalyst layer, and degradation products of HCl and Cl are degraded ₂ The generation and adsorption of (a) also occur concentrated on the surface of the catalyst housing; the Co-M mixed oxide nano rod inner core ensures the excellent oxidation-reduction performance of the catalytic system, can realize the deep oxidation of CO, non-methane total hydrocarbon and dioxin degradation intermediate products, and simultaneously avoids chloride ions to Co ₃ O ₄ And attack by La, ce, pr oxides. Through the design of the macroporous structure of the catalyst shell, interception of fine particles for adsorbing dioxin and adsorption of other macromolecular chlorine-containing VOCs can be realized, and the mesoporous structure of the inner core is ensuredCO, non-methane total hydrocarbon and dioxin degradation intermediate products can be effectively diffused to the surface of the active center of the catalyst, so that the catalyst can efficiently degrade various pollutant components of the flue gas.

In a preferred embodiment, the mass ratio of the inner core to the outer shell is 0.35-4:1.

In a preferred example, the mass ratio of Co to M in the mesoporous Co-M mixed oxide nanorod is 1:0.05-0.5.

In a preferred example, the specific surface area of the mesoporous Co-M mixed oxide nanorod is 5-20M ² /g。

In a preferred embodiment, the length of the mesoporous Co-M mixed oxide nanorod is 1-30 μm and the width is 0.5-1 μm.

In a preferred embodiment, the mesoporous size of the mesoporous Co-M mixed oxide nanorod is 2-10 nm.

The mesoporous Co-M mixed oxide nanorod can be prepared at one time by adopting a uniform hydrothermal method.

In a preferred embodiment, the preparation method of the mesoporous Co-M mixed oxide nanorod includes: preparing a mixed aqueous solution of nitrate of cobalt chloride hexahydrate and M and urea, carrying out uniform hydrothermal treatment, cooling, washing the obtained solid, and drying to obtain the Co-M mixed oxide nanorod with the mesoporous structure.

In a preferred embodiment, in the preparation method of the mesoporous Co-M mixed oxide nanorod, the mass ratio of the cobalt chloride hexahydrate to the urea is 1:5-50.

In a preferred embodiment, in the preparation method of the mesoporous Co-M mixed oxide nanorod, a polytetrafluoroethylene lining hydrothermal kettle is adopted for the uniform hydrothermal treatment, and the filling degree of the polytetrafluoroethylene lining hydrothermal kettle is 50% -80%.

In a preferred embodiment, in the preparation method of the mesoporous Co-M mixed oxide nanorod, the temperature of the uniform hydrothermal treatment is 100-200 ℃.

In a preferred embodiment, in the preparation method of the mesoporous Co-M mixed oxide nanorod, the time of the uniform hydrothermal treatment is 10-100 hours.

In a preferred embodiment, in the method for preparing the Co-M mixed oxide nanorods with a mesoporous structure, the drying temperature is lower than the hydrothermal treatment temperature. Further, the drying temperature may be 60 to 80 ℃.

The N-HZSM-5 molecular sieve with the macroporous structure is prepared by a microwave hydrothermal method.

In a preferred example, the mass ratio of HZSM-5 to N in the N-HZSM-5 molecular sieve with the macroporous structure is 1:0.001-0.05.

In a preferred example, the specific surface area of the N-HZSM-5 molecular sieve with the macroporous structure is 200 to 300m ² /g。

In a preferred example, the N-HZSM-5 molecular sieve of macroporous structure has a particle outer diameter of 0.2 to 0.6. Mu.m.

In a preferred example, the N-HZSM-5 molecular sieve of macroporous structure has a macropore size of 50 to 300nm.

The N-HZSM-5 molecular sieve with the macroporous structure is formed by secondary crystallization on the Co-M mixed oxide nanorod with the mesoporous structure based on the hot spot effect of a microwave hydrothermal method. The Co-M nanorods have excellent microwave absorption function, can be rapidly heated in a microwave field to form regional hot spots, and the precursor in the solution can be rapidly crystallized in the regional hot spots, so that N-HZSM-5 crystals are formed on the surfaces of the Co-M nanorods.

In a preferred embodiment, the preparation method of the core-shell catalyst with the inner and outer functional partitions comprises the following steps:

s1, sequentially adding sodium chloride, polyethylene glycol, tetrapropylammonium hydroxide and aluminum isopropoxide into deionized water while stirring to obtain a first mixture;

s2, carrying out ultrasonic treatment on the first mixture for 10-40 minutes, stirring for 5-20 minutes, rapidly adding tetraethyl silicate into the first mixture while stirring, adding soluble salt of N, finally adding the mesoporous Co-M mixed oxide nanorods, and stirring for 20-40 hours at room temperature to obtain a second mixture;

s3, transferring the second mixture into a polytetrafluoroethylene hydrothermal kettle, and performing two-step hydrothermal reaction in a microwave hydrothermal reactor, namely, firstly reacting for 0.5-8 h at 60-200 ℃, then reacting for 1-16 h at 120-200 ℃, washing and drying the solid obtained by the hydrothermal reaction, and roasting for 1-5 h at 300-600 ℃ to obtain the core-shell structure catalyst with the inner and outer functional partitions.

In a preferred example, in the preparation method of the core-shell structure catalyst with the inner and outer functional partitions, the mass ratio of deionized water, sodium chloride, polyethylene glycol, tetrapropylammonium hydroxide, aluminum isopropoxide and tetraethyl silicate is 100:1-5:5-10:10-30:0.1-1.0:10-20.

In a preferred embodiment, in the preparation method of the catalyst with the core-shell structure and the inner-outer functional partitions, the filling degree of the polytetrafluoroethylene hydrothermal kettle is 30-75%.

In one embodiment, the waste incinerator flue gas treatment process of the application, the dosage of the core-shell structure catalyst with the inner and outer functional partitions is 40000 to 100000 hours according to the airspeed ^-1 The temperature of the flue gas of the garbage incinerator is 170-400 ℃; the CO concentration in the flue gas of the garbage incinerator is 500-50000 mg/m ³ The concentration of non-methane total hydrocarbon is 20-2000 mg/m ³ The concentration of the dioxin is 0.2-5 ng/m ³ The method comprises the steps of carrying out a first treatment on the surface of the The waste incinerator flue gas treatment process has the advantages that the CO removal rate is 90% -99%, the non-methane total hydrocarbon removal rate is 90% -95%, and the dioxin removal rate is 90% -95%.

Compared with the prior art, the application has the beneficial effects that:

the waste incinerator flue gas treatment process uses the shell-core hierarchical pore macroporous-mesoporous structure catalyst with the external and internal functional partitions, wherein the N-HZSM-5 molecular sieve shell has rich acidic sites and macroporous structures, provides interception sites and adsorption sites for dioxin-containing fine particles and chlorine-containing VOCs macromolecules, and can enable pollutant molecules to break down in C-Cl; the Co-M mixed oxide nano rod inner core has excellent oxidation-reduction performance and proper mesoporous structure, and can further realize the deep oxidation of CO, non-methane total hydrocarbon and dioxin degradation intermediate products. HCl and Cl ₂ Mainly comprises N-HZSM-5 componentsThe unique structure of the nuclear material can promote the rapid dechlorination of the surface of the catalyst, so that the catalyst has good anti-chlorine poisoning performance. Meanwhile, the molecular sieve shell in the core-shell structure can prevent the Co-M mixed oxide nanorod inner core from directly contacting with dioxin, so that the generation of polychlorinated byproducts is reduced. The catalyst can well solve the problems of synchronous one-time catalytic removal of CO, non-methane total hydrocarbon, dioxin and other gaseous pollutants and catalyst chlorine poisoning.

Drawings

FIG. 1 is a Scanning Electron Microscope (SEM) photograph of Co-M nanorods prepared by a uniform hydrothermal method according to example 1.

FIG. 2 is an SEM photograph of a Co-M@N-HZSM-5 core-shell structured catalyst prepared in example 1 using a homogeneous hydrothermal process and a microwave hydrothermal process.

Detailed Description

The application will be further elucidated with reference to the drawings and to specific embodiments. It is to be understood that these examples are illustrative of the present application and are not intended to limit the scope of the present application.

Example 1:

preparation of mesoporous Co-La mixed oxide nanorods: raw material quality CoCl ₂ ·6H ₂ O: lanthanum nitrate: water: urea=1: 0.1:300:6. cobalt chloride hexahydrate and lanthanum nitrate are dissolved in deionized water, urea is added into the solution and stirred for 20 minutes, and then the mixture is poured into a polytetrafluoroethylene-lined hydrothermal kettle for hydrothermal reaction at 110 ℃ for 12 hours, wherein the filling degree of the hydrothermal kettle is 70%. The hydrothermal precipitate was washed with deionized water and absolute ethanol, and then the sample was dried at 80 ℃. Fig. 1 shows SEM photographs of the mesoporous Co-La mixed oxide nanorods of this example.

Preparing a core-shell structure catalyst: to 100mL of deionized water, 1.24g of sodium chloride, 8.0g of polyethylene glycol, 22.5g of tetrapropylammonium hydroxide and 0.4g of aluminum isopropoxide were added sequentially with stirring. The mixture was then sonicated in a sonicator for 15 minutes and after stirring for a further 10 minutes, 13.08g of tetraethyl silicate was added quickly to the solution with stirring, 0.02g of H2PtCl6 was added, and finally 1.2g of mesoporous Co-La mixed oxide nanorods were added and stirred at room temperature for 24 hours. After the stirring is completed, the mixed solution is transferred into a polytetrafluoroethylene hydrothermal kettle, the filling degree is 40%, and the two-step hydrothermal reaction is carried out in a microwave hydrothermal reactor. The reaction was first carried out at 80℃for 1h and then at 170℃for 2h. The reactant obtained by the hydrothermal reaction is filtered and washed, dried at 80 ℃, and burned for 2 hours at 400 ℃ to obtain the finished catalyst, namely the core-shell structure catalyst with inner and outer functional partitions. Fig. 2 shows SEM photographs of the core-shell structured catalyst of the inner and outer functional partitions of the present example.

The core-shell structure catalyst with the inner and outer functional partitions has the flue gas temperature of 350 ℃ and the gas flow of 500m in the garbage incinerator ³ /h, CO concentration of 5000mg/m ³ The non-methane total hydrocarbon concentration is 200mg/m ³ Concentration of dioxin is 2ng/m ³ The method comprises the steps of carrying out a first treatment on the surface of the The dosage of the core-shell catalyst is 40000h according to the airspeed ^-1 The efficiency of CO removal by combustion was 95%, the efficiency of removal of total non-methane hydrocarbons by combustion was 92.3%, and the efficiency of removal of dioxin in flue gas was 94.9%.

Example 2:

mesoporous Co-Ce mixed oxide nanorod preparation: raw material quality CoCl ₂ ·6H ₂ O：Ce(NO ₃ ) ₃ : water: urea=1: 0.2:300:10. cobalt chloride hexahydrate and cerium nitrate were dissolved in deionized water, urea was added to the solution and stirred for 30 minutes, and then poured into a polytetrafluoro-lined hydrothermal kettle with a filling degree of 70% for 12 hours at 110 ℃. The hydrothermal precipitate was washed with deionized water and absolute ethanol, and then the sample was dried at 60 ℃.

Preparing a core-shell structure catalyst: to 100mL of deionized water, 1.24g of sodium chloride, 10.0g of polyethylene glycol, 22.5g of tetrapropylammonium hydroxide and 0.4g of aluminum isopropoxide were added sequentially while stirring. The mixture was then sonicated in a sonicator for 30 minutes and after stirring for about ten minutes, 13.08g of tetraethyl silicate was added to the solution rapidly with stirring, and 0.025g of PdCl was added ₂ Finally, 1.2g of mesoporous Co-Ce mixed oxide nanorod is added and stirred at room temperature for 24 hours. After stirring, the mixed solution is transferred into a polytetrafluoroethylene hydrothermal kettle to be filledThe filling degree is 40%, and the two-step hydrothermal reaction is carried out in a microwave hydrothermal reactor. The reaction was first carried out at 80℃for 1.5h and then at 170℃for 3h. And (3) carrying out suction filtration and washing on reactants obtained by the hydrothermal reaction, drying at 60 ℃, and burning at 400 ℃ for 2 hours to obtain a catalyst finished product, namely the core-shell structure catalyst with inner and outer functional partitions.

The core-shell structure catalyst with the inner and outer functional partitions has the flue gas temperature of 300 ℃ and the gas flow of 5000m in the garbage incinerator ³ And/h, CO concentration of 10000mg/m ³ The non-methane total hydrocarbon concentration is 1000mg/m ³ Dioxin concentration of 4ng/m ³ The method comprises the steps of carrying out a first treatment on the surface of the The dosage of the core-shell catalyst is 40000h according to the airspeed ^-1 The efficiency of CO removal by combustion was 96%, the efficiency of removal of non-methane total hydrocarbons by combustion was 90.6%, and the efficiency of removal of dioxin in flue gas was 93.5%.

Example 3:

preparing a mesoporous Co-Pr mixed oxide nano rod: raw material quality CoCl ₂ ·6H ₂ O：Pr(NO ₃ ) ₃ : water: urea=1: 0.3:300:35. cobalt chloride hexahydrate and praseodymium nitrate are dissolved in deionized water, urea is added into the solution and stirred for 20 minutes, and then the mixture is poured into a polytetrafluoroethylene-lined hydrothermal kettle for hydrothermal reaction at 110 ℃ for 12 hours, wherein the filling degree of the hydrothermal kettle is 70%. The hydrothermal precipitate was washed with deionized water and absolute ethanol, and then the sample was dried at 80 ℃.

Preparing a core-shell structure catalyst: to 100mL of deionized water, 1.24g of sodium chloride, 10.0g of polyethylene glycol, 22.5g of tetrapropylammonium hydroxide and 0.4g of aluminum isopropoxide were added sequentially while stirring. The mixture was then sonicated in an sonicator for 30 minutes and after stirring for about ten minutes, 13.08g of tetraethyl silicate was added to the solution quickly with stirring, and 0.03g of RuCl was added ₃ ·3H ₂ And finally adding 1.2g of mesoporous Co-Pr mixed oxide nano rod, and stirring for 24 hours at room temperature. After the stirring is completed, the mixed solution is transferred into a polytetrafluoroethylene hydrothermal kettle, the filling degree is 40%, and the two-step hydrothermal reaction is carried out in a microwave hydrothermal reactor. The reaction was first carried out at 80℃for 2h and then at 170℃for 4h. Hydrothermally derived reactantsAnd (3) carrying out suction filtration, washing, drying at 80 ℃, and burning at 400 ℃ for 2 hours to obtain a catalyst finished product, namely the core-shell structure catalyst with the inner and outer functional partitions.

The core-shell structure catalyst with the inner and outer functional partitions has the flue gas temperature of 270 ℃ and the gas flow of 2000m in the garbage incinerator ³ /h, CO concentration of 30000mg/m ³ The non-methane total hydrocarbon concentration is 300mg/m ³ Concentration of dioxin is 3ng/m ³ The method comprises the steps of carrying out a first treatment on the surface of the The dosage of the core-shell structure catalyst is 60000h according to the airspeed ^-1 The removal efficiency of CO generated by combustion is 95.0%, the removal rate of non-methane total hydrocarbon generated by combustion is 90.3%, and the removal efficiency of dioxin in flue gas is 91.8%.

Example 4:

preparing a mesoporous Co-Pr mixed oxide nano rod: raw material quality CoCl ₂ ·6H ₂ O：Pr(NO ₃ ) ₃ : water: urea=1: 0.4:300:20. cobalt chloride hexahydrate and praseodymium nitrate are dissolved in deionized water, urea is added into the solution and stirred for 20 minutes, and then the mixture is poured into a polytetrafluoroethylene-lined hydrothermal kettle for hydrothermal treatment at 110 ℃ for 12 hours, wherein the filling degree of the hydrothermal kettle is 70%. The hydrothermal precipitate was washed with deionized water and absolute ethanol, and then the sample was dried at 80 ℃.

Preparing a core-shell structure catalyst: to 100mL of deionized water, 1.24g of sodium chloride, 10.0g of polyethylene glycol, 22.5g of tetrapropylammonium hydroxide and 0.4g of aluminum isopropoxide were added sequentially while stirring. The mixture was then sonicated in a sonicator for 15 minutes and after stirring for about ten minutes, 13.08g of tetraethyl silicate was added to the solution rapidly with stirring, and 0.05g of PdCl was added ₂ Finally, 1.2g of mesoporous Co-Pr mixed oxide nano rod is added, and stirred for 24 hours at room temperature. After the stirring is completed, the mixed solution is transferred into a polytetrafluoroethylene hydrothermal kettle, the filling degree is 40%, and the two-step hydrothermal reaction is carried out in a microwave hydrothermal reactor. The reaction was first carried out at 80℃for 2h and then at 170℃for 4h. The reactant obtained by the hydrothermal reaction is filtered and washed, dried at 80 ℃, and burned for 2 hours at 400 ℃ to obtain the finished catalyst, namely the core-shell structure catalyst with inner and outer functional partitions.

The inner part is provided withThe core-shell structure catalyst with external functional partition has the flue gas temperature of 200 ℃ and gas flow of 1000m in the garbage incinerator ³ And/h, CO concentration of 10000mg/m ³ The concentration of non-methane total hydrocarbon is 500mg/m ³ Concentration of dioxin is 2ng/m ³ The method comprises the steps of carrying out a first treatment on the surface of the The dosage of the core-shell structure catalyst is 80000h according to the airspeed ^-1 The efficiency of CO removal by combustion was 96.1%, the efficiency of removal of non-methane total hydrocarbons by combustion was 91.0%, and the efficiency of removal of dioxin in flue gas was 93.2%.

Example 5:

mesoporous Co-Ce mixed oxide nanorod preparation: raw material quality CoCl ₂ ·6H ₂ O：Ce(NO ₃ ) ₃ : water: urea=1: 0.18:300:45. cobalt chloride hexahydrate and cerium nitrate were dissolved in deionized water, urea was added to the solution and stirred for 20 minutes, then poured into a polytetrafluoro-lined hydrothermal kettle and hydrothermal-treated at 110 ℃ for 12 hours, the filling degree of the hydrothermal kettle being 70%. The hydrothermal precipitate was washed with deionized water and absolute ethanol, and then the sample was dried at 80 ℃.

Preparing a core-shell structure catalyst: to 100mL of deionized water, 1.24g of sodium chloride, 10.0g of polyethylene glycol, 22.5g of tetrapropylammonium hydroxide and 0.4g of aluminum isopropoxide were added sequentially while stirring. The mixture was then sonicated in an sonicator for 30 minutes and after stirring for about ten minutes, 13.08g of tetraethyl silicate was added to the solution quickly with stirring, and 0.015g of RuCl was added ₃ ·3H ₂ And finally adding 1.5g of mesoporous Co-Ce mixed oxide nanorods, and stirring for 24 hours at room temperature. After the stirring is completed, the mixed solution is transferred into a polytetrafluoroethylene hydrothermal kettle, the filling degree is 40%, and the two-step hydrothermal reaction is carried out in a microwave hydrothermal reactor. The reaction was first carried out at 80℃for 2h and then at 170℃for 4h. And (3) carrying out suction filtration and washing on reactants obtained by the hydrothermal reaction, drying at 60 ℃, and burning at 400 ℃ for 2 hours to obtain a catalyst finished product, namely the core-shell structure catalyst with inner and outer functional partitions.

The core-shell structure catalyst with the inner and outer functional partitions has the flue gas temperature of 210 ℃ and the gas flow of 5000m in the garbage incinerator ³ /h, CO concentration of 40000mg/m ³ Non-nailThe alkane concentration is 250mg/m ³ Concentration of dioxin is 1.1ng/m ³ The method comprises the steps of carrying out a first treatment on the surface of the The dosage of the core-shell catalyst is 40000h according to the airspeed ^-1 The removal efficiency of CO generated by combustion is 98.0%, the removal rate of non-methane total hydrocarbon generated by combustion is 94.6%, and the removal efficiency of dioxin in flue gas is 94.9%.

Example 6:

mesoporous Co-Ce mixed oxide nanorod preparation: raw material quality CoCl ₂ ·6H ₂ O：Ce(NO ₃ ) ₃ : water: urea=1: 0.15:300:30. cobalt chloride hexahydrate and cerium nitrate were dissolved in deionized water, urea was added to the solution and stirred for 20 minutes, then poured into a polytetrafluoro-lined hydrothermal kettle and hydrothermal-treated at 110 ℃ for 12 hours, the filling degree of the hydrothermal kettle being 70%. The hydrothermal precipitate was washed with deionized water and absolute ethanol, and then the sample was dried at 80 ℃.

Preparing a core-shell structure catalyst: to 100mL of deionized water, 1.24g of sodium chloride, 10.0g of polyethylene glycol, 22.5g of tetrapropylammonium hydroxide and 0.4g of aluminum isopropoxide were added sequentially while stirring. The mixture was then sonicated in a sonicator for 30 minutes and after stirring for about ten minutes, 13.08g of tetraethyl silicate was added quickly to the solution with stirring, 0.03g of H2PtCl6 was added, and finally 4.8g of mesoporous Co-Ce mixed oxide nanorods were added and stirred at room temperature for 24 hours. After the stirring is completed, the mixed solution is transferred into a polytetrafluoroethylene hydrothermal kettle, the filling degree is 40%, and the two-step hydrothermal reaction is carried out in a microwave hydrothermal reactor. The reaction was first carried out at 80℃for 2h and then at 170℃for 4h. And (3) carrying out suction filtration and washing on reactants obtained by the hydrothermal reaction, drying at 60 ℃, and burning at 400 ℃ for 2 hours to obtain a catalyst finished product, namely the core-shell structure catalyst with inner and outer functional partitions.

The core-shell structure catalyst with the inner and outer functional partitions has the flue gas temperature of 280 ℃ and the gas flow of 1000m in the garbage incinerator ³ /h, CO concentration of 20000mg/m ³ The total non-methane hydrocarbon concentration is 350mg/m ³ Dioxin concentration of 4ng/m ³ The method comprises the steps of carrying out a first treatment on the surface of the The dosage of the core-shell structure catalyst is 50000h according to the space velocity ^-1 The CO removal efficiency for combustion was 969%, the removal rate of non-methane total hydrocarbon generated by combustion is 94.1%, and the removal rate of dioxin in flue gas is 92.7%.

Example 7:

preparation of mesoporous Co-La mixed oxide nanorods: raw material quality CoCl ₂ ·6H ₂ O: lanthanum nitrate: water: urea=1: 0.15:300:25. cobalt chloride hexahydrate and lanthanum nitrate are dissolved in deionized water, urea is added into the solution and stirred for 20 minutes, and then the mixture is poured into a polytetrafluoroethylene-lined hydrothermal kettle for hydrothermal reaction at 110 ℃ for 12 hours, wherein the filling degree of the hydrothermal kettle is 70%. The hydrothermal precipitate was washed with deionized water and absolute ethanol, and then the sample was dried at 80 ℃.

Preparing a core-shell structure catalyst: to 100mL of deionized water, 1.24g of sodium chloride, 10.0g of polyethylene glycol, 22.5g of tetrapropylammonium hydroxide and 0.4g of aluminum isopropoxide were added sequentially while stirring. The mixture was then sonicated in a sonicator for 30 minutes and after stirring for about ten minutes, 13.08g of tetraethyl silicate was added to the solution quickly with stirring, and 0.025g of RuCl was added ₃ ·3H ₂ And finally adding 2.4g of mesoporous Co-La mixed oxide nano rod, and stirring for 24 hours at room temperature. After the stirring is completed, the mixed solution is transferred into a polytetrafluoroethylene hydrothermal kettle, the filling degree is 40%, and the two-step hydrothermal reaction is carried out in a microwave hydrothermal reactor. The reaction was first carried out at 80℃for 2h and then at 170℃for 4h. The reactant obtained by the hydrothermal reaction is dried at 80 ℃ after being filtered and washed, and is burnt at 550 ℃ for 2 hours to obtain a catalyst finished product, namely the core-shell structure catalyst with the inner and outer functional partitions.

The core-shell structure catalyst with the inner and outer functional partitions has the flue gas temperature of 260 ℃ and the gas flow of 3000m in the garbage incinerator ³ And/h, CO concentration of 8000mg/m ³ The concentration of non-methane total hydrocarbon is 500mg/m ³ Concentration of dioxin is 3ng/m ³ The method comprises the steps of carrying out a first treatment on the surface of the The dosage of the core-shell structure catalyst is 100000h according to the space velocity ^-1 The removal efficiency of CO generated by combustion is 95.2%, the removal rate of non-methane total hydrocarbon generated by combustion is 90.4%, and the removal efficiency of dioxin in flue gas is 91.1%.

Example 8:

preparation of mesoporous Co-La mixed oxide nanorods: raw material quality CoCl ₂ ·6H ₂ O: lanthanum nitrate: water: urea=1: 0.25:300:30. cobalt chloride hexahydrate and lanthanum nitrate are dissolved in deionized water, urea is added into the solution and stirred for 20 minutes, and then the mixture is poured into a polytetrafluoroethylene-lined hydrothermal kettle for hydrothermal reaction at 110 ℃ for 12 hours, wherein the filling degree of the hydrothermal kettle is 70%. The hydrothermal precipitate was washed with deionized water and absolute ethanol, and then the sample was dried at 80 ℃.

Preparing a core-shell structure catalyst: to 100mL of deionized water, 1.24g of sodium chloride, 10.0g of polyethylene glycol, 22.5g of tetrapropylammonium hydroxide and 0.4g of aluminum isopropoxide were added sequentially while stirring. The mixture was then sonicated in a sonicator for 30 minutes and after stirring for about ten minutes, 13.08g of tetraethyl silicate was added to the solution rapidly with stirring, and 0.04g of PdCl was added ₂ Finally, 2.4g of mesoporous Co-La mixed oxide nanorod is added and stirred at room temperature for 24 hours. After the stirring is completed, the mixed solution is transferred into a polytetrafluoroethylene hydrothermal kettle, the filling degree is 40%, and the two-step hydrothermal reaction is carried out in a microwave hydrothermal reactor. The reaction was first carried out at 80℃for 2h and then at 170℃for 4h. And (3) carrying out suction filtration and washing on reactants obtained by the hydrothermal reaction, drying at 60 ℃, and burning at 400 ℃ for 2 hours to obtain a catalyst finished product, namely the core-shell structure catalyst with inner and outer functional partitions.

The core-shell structure catalyst with the inner and outer functional partitions has the flue gas temperature of 320 ℃ and the gas flow of 2500m in the garbage incinerator ³ /h, CO concentration of 12000mg/m ³ The non-methane total hydrocarbon concentration is 250mg/m ³ Concentration of dioxin is 2.8ng/m ³ The method comprises the steps of carrying out a first treatment on the surface of the The dosage of the core-shell structure catalyst is 50000h according to the space velocity ^-1 The removal efficiency of CO generated by combustion is 98.5%, the removal rate of non-methane total hydrocarbon generated by combustion is 94.6%, and the removal efficiency of dioxin in flue gas is 94.7%.

Comparative example 1:

the difference from example 1 is that lanthanum nitrate is not added in the preparation process of the nanorod, H2PtCl6 is not added in the preparation process of the core-shell catalyst, and the rest is the same, so that the composite catalyst is obtained.

The flue gas temperature of the composite catalyst in the garbage incinerator is 350 ℃, and the gas flow is 500m ³ /h, CO concentration of 5000mg/m ³ The non-methane total hydrocarbon concentration is 200mg/m ³ Concentration of dioxin is 2ng/m ³ The method comprises the steps of carrying out a first treatment on the surface of the The dosage of the composite catalyst is 40000h according to the space velocity ^-1 The removal efficiency of CO generated by combustion is 83.1%, the removal rate of non-methane total hydrocarbon generated by combustion is 60.5%, and the removal efficiency of dioxin in flue gas is 30.5%.

Comparative example 2:

the only difference from example 1 is that lanthanum nitrate was not added during the preparation of the nanorods, and the rest were the same, to obtain a composite catalyst.

The flue gas temperature of the composite catalyst in the garbage incinerator is 350 ℃, and the gas flow is 500m ³ /h, CO concentration of 5000mg/m ³ The non-methane total hydrocarbon concentration is 200mg/m ³ Concentration of dioxin is 2ng/m ³ The method comprises the steps of carrying out a first treatment on the surface of the The dosage of the composite catalyst is 40000h according to the space velocity ^-1 The removal efficiency of CO generated by combustion is 82.4%, the removal rate of non-methane total hydrocarbon generated by combustion is 67.1%, and the removal efficiency of dioxin in flue gas is 90.0%.

Comparative example 3:

the difference from example 1 is only that the microwave hydrothermal reactor is replaced by a common hydrothermal reactor, and the rest is the same, and the obtained composite catalyst has no core-shell structure.

The flue gas temperature of the composite catalyst in the garbage incinerator is 350 ℃, and the gas flow is 500m ³ /h, CO concentration of 5000mg/m ³ The non-methane total hydrocarbon concentration is 200mg/m ³ Concentration of dioxin is 2ng/m ³ The method comprises the steps of carrying out a first treatment on the surface of the The dosage of the composite catalyst is 40000h according to the space velocity ^-1 The efficiency of CO removal by combustion was 74.3%, the efficiency of removal of non-methane total hydrocarbons by combustion was 50.6%, and the efficiency of removal of dioxin in flue gas was 30.2%.

Comparative example 4:

preparation of Co-La mixed oxide: raw material quality CoCl ₂ ·6H ₂ O: lanthanum nitrate: water: urea=1: 0.1:300:6. cobalt chloride hexahydrate and lanthanum nitrate were dissolved in deionized water, and urea was added to the solution and stirred for 400 minutes. The precipitate after uniform precipitation was washed with deionized water and absolute ethanol, and then the sample was dried at 80 ℃.

Preparation of Co-La/Pt-HZSM-5 composite catalyst: to 100mL of deionized water, 1.24g of sodium chloride, 8.0g of polyethylene glycol, 22.5g of tetrapropylammonium hydroxide and 0.4g of aluminum isopropoxide were added sequentially with stirring. The mixture was then sonicated in an sonicator for 15 minutes and after stirring for a further ten minutes, 13.08g of tetraethyl silicate was added to the solution rapidly with stirring, and 0.03g of H was added ₂ PtCl ₆ Finally, 1.2g of Co-La mixed oxide was added and stirred at 80℃for 48 hours. And (3) carrying out suction filtration and washing on the reactant obtained by uniform precipitation, drying at 80 ℃, and firing at 400 ℃ for 2 hours to obtain the composite catalyst.

Compared with the example 1, the Co-La mixed oxide and Co-La/Pt-HZSM-5 composite catalyst of the comparative example are both prepared by a uniform precipitation method and are metal oxide mixture catalysts.

The flue gas temperature of the composite catalyst in the garbage incinerator is 350 ℃, and the gas flow is 500m ³ /h, CO concentration of 5000mg/m ³ The non-methane total hydrocarbon concentration is 200mg/m ³ Concentration of dioxin is 2ng/m ³ The method comprises the steps of carrying out a first treatment on the surface of the The dosage of the composite catalyst is 40000h according to the space velocity ^-1 The removal efficiency of CO generated by combustion is 76.2%, the removal rate of non-methane total hydrocarbon generated by combustion is 65.8%, and the removal efficiency of dioxin in flue gas is 40.2%.

Further, it is to be understood that various changes and modifications of the present application may be made by those skilled in the art after reading the above description of the application, and that such equivalents are intended to fall within the scope of the application as defined in the appended claims.

Claims

1. A waste incinerator flue gas treatment process is characterized in that a core-shell structure catalyst with inner and outer functional partitions is used for catalytic oxidation to synchronously remove CO, non-methane total hydrocarbons and dioxin in the waste incinerator flue gas at one time;

the inner core is a Co-M mixed oxide nano rod with a mesoporous structure, wherein M is at least one of La, ce and Pr;

2. The waste incinerator flue gas treatment process according to claim 1, wherein the mass ratio of the inner core to the outer shell is 0.35-4:1.

3. The flue gas treatment process of the garbage incinerator according to claim 1, wherein the mass ratio of Co to M in the mesoporous Co-M mixed oxide nanorod is 1:0.05-0.5;

the specific surface area of the Co-M mixed oxide nano rod with the mesoporous structure is 5-20M ² /g；

The length of the Co-M mixed oxide nano rod with the mesoporous structure is 1-30 mu M, and the width is 0.5-1 mu M;

the mesoporous size of the Co-M mixed oxide nanorod with the mesoporous structure is 2-10 nm.

4. A waste incinerator flue gas treatment process according to claim 1 or 3, wherein the preparation method of the Co-M mixed oxide nanorods with mesoporous structure comprises the following steps: preparing a mixed aqueous solution of nitrate of cobalt chloride hexahydrate and M and urea, carrying out uniform hydrothermal treatment, cooling, washing the obtained solid, and drying to obtain the Co-M mixed oxide nanorod with the mesoporous structure.

5. The flue gas treatment process of a garbage incinerator according to claim 4, wherein the preparation method of the mesoporous Co-M mixed oxide nanorods is as follows:

the mass ratio of the cobalt chloride hexahydrate to the urea is 1:5-50;

the uniform hydrothermal treatment is carried out by adopting a polytetrafluoroethylene lining hydrothermal kettle, and the filling degree of the polytetrafluoroethylene lining hydrothermal kettle is 50% -80%;

the temperature of the uniform hydrothermal treatment is 100-200 ℃;

the time of the uniform hydrothermal treatment is 10-100 hours;

the temperature of the drying is lower than the temperature of the hydrothermal treatment.

6. The process for treating flue gas of garbage incinerator according to claim 5, wherein in the preparation method of the mesoporous Co-M mixed oxide nanorods, the drying temperature is 60-80 ℃.

7. The flue gas treatment process of a garbage incinerator according to claim 1, wherein the N-HZSM-5 molecular sieve with the macroporous structure is prepared by a microwave hydrothermal method;

the mass ratio of HZSM-5 to N in the N-HZSM-5 molecular sieve with the macroporous structure is 1:0.001-0.05;

the specific surface area of the N-HZSM-5 molecular sieve with the macroporous structure is 200-300 m ² /g；

The particle outer diameter of the N-HZSM-5 molecular sieve with the macroporous structure is 0.2-0.6 mu m;

the size of the macropores of the N-HZSM-5 molecular sieve with the macroporous structure is 50-300 nm.

8. The garbage incinerator flue gas treatment process according to claim 1 or 7, wherein the preparation method of the core-shell structure catalyst with the inner and outer functional partitions comprises the following steps:

9. The garbage incinerator flue gas treatment process according to claim 8, wherein the preparation method of the core-shell structure catalyst with the inner and outer functional partitions comprises the following steps:

deionized water, sodium chloride, polyethylene glycol, tetrapropylammonium hydroxide, aluminum isopropoxide and tetraethyl silicate in a mass ratio of 100:1-5:5-10:10-30:0.1-1.0:10-20;

the filling degree of the polytetrafluoroethylene hydrothermal kettle is 30-75%.

10. The process for treating flue gas of garbage incinerator according to claim 1, wherein the amount of the catalyst with the core-shell structure in the inner and outer functional partitions is 40000-100000 h according to the airspeed ^-1 The temperature of the flue gas of the garbage incinerator is 170-400 ℃; the CO concentration in the flue gas of the garbage incinerator is 500-50000 mg/m ³ The concentration of non-methane total hydrocarbon is 20-2000 mg/m ³ Concentration of dioxin

The degree is 0.2-5 ng/m ³ The method comprises the steps of carrying out a first treatment on the surface of the The CO removal rate of the waste incinerator flue gas treatment process is 90 to 99 percent,

the removal rate of non-methane total hydrocarbon is 90% -95%, and the removal rate of dioxin is 90% -95%.