CN112337481B

CN112337481B - Application of a catalyst capable of simultaneously removing hydrogen cyanide and ammonia in the treatment of tail gas containing hydrogen cyanide and ammonia

Info

Publication number: CN112337481B
Application number: CN202010959171.2A
Authority: CN
Inventors: 宁平; 李钊; 王飞; 李凯; 王驰; 孙鑫; 马懿星
Original assignee: Kunming University of Science and Technology
Current assignee: Kunming University of Science and Technology
Priority date: 2020-09-14
Filing date: 2020-09-14
Publication date: 2021-08-24
Anticipated expiration: 2040-09-14
Also published as: CN112337481A

Abstract

The invention relates to the technical field of atmospheric prevention and control, in particular to a catalyst capable of simultaneously removing hydrogen cyanide and ammonia and a preparation method and application thereof. The preparation method of the present invention includes the following steps: immersing the carrier in a first aqueous solution of metal precursors to perform first stirring, then first rotary distillation to remove moisture in the obtained mixture, drying, and first roasting to obtain a first intermediate product ; Impregnating the first intermediate product in the second metal precursor aqueous solution to carry out the second stirring, then the second rotary evaporation to remove the moisture in the obtained material, drying, and carrying out the second roasting to obtain the second intermediate product; The second intermediate product is obtained; The second intermediate product is subjected to reduction treatment to obtain a catalyst capable of simultaneously removing hydrogen cyanide and ammonia. Using the catalyst of the present invention can simultaneously remove HCN and NH ₃ with high efficiency in a water-free atmosphere.

Description

Application of catalyst capable of removing hydrogen cyanide and ammonia gas simultaneously in treatment of tail gas containing hydrogen cyanide and ammonia gas

Technical Field

The invention relates to the technical field of atmosphere control, in particular to a catalyst capable of removing hydrogen cyanide and ammonia gas simultaneously and a preparation method and application thereof.

Background

Hydrogen cyanide (C)HCN) is a gaseous highly toxic substance, is a byproduct necessarily generated in most industrial production processes, and is one of the most typical unconventional toxic and harmful pollutants in industrial waste gases of phosphorus chemical industry, ammonia synthesis and coal chemical industry. Hydrogen Cyanide (HCN) and ammonia (NH) in industrial tail gas of phosphorus chemical industry and coal chemical industry₃) The discharge of hydrogen cyanide into the atmosphere is frequently accompanied by a series of problems such as acid rain, ozone holes, greenhouse effect and the like, which are easy to threaten the lives of human beings and animals. Ammonia gas easily and strongly stimulates mucous membranes of eyes and respiratory tracts, and is also seriously harmful to the health of human beings and other living beings, and is an important precursor for forming dust haze in atmospheric environment. In recent years, the continuous development of various chemical industries directly leads to the rapid increase of the yield of hydrogen cyanide and ammonia gas in tail gas.

At present for the simultaneous removal of NH₃And methods for HCN mainly include a liquid absorption method, an adsorption method, and the like. The liquid absorption method has relatively high treatment cost, unstable effect and easy generation of secondary pollution; the adsorption method essentially only transfers and enriches pollutants on an adsorption material, and HCN desorption caused by temperature change during the recovery of the adsorbent has secondary pollution hidden trouble and further threatens the life health of operators. In the current phase of research, the efficient HCN removal process is catalytic hydrolysis, while the mainstream NH₃The purification method is catalytic oxidation. Although most catalysts are capable of catalyzing HCN and NH₃However, the same catalyst needs different reaction conditions for catalyzing the two gases, for example, the water-containing condition can increase the removal efficiency of HCN, but can severely inhibit NH₃And (4) oxidizing. The non-aqueous atmosphere has a high NH content₃Catalytic activity, but the conversion of HCN is reduced.

Chinese patent CN111229210A discloses a catalyst with both HCN catalytic hydrolysis performance and NH performance₃The catalyst with oxidizing property takes hydrotalcite-like compound as the catalyst, can efficiently hydrolyze HCN within the temperature range of 50-200 ℃, and can efficiently oxidize NH within the temperature range of 200-400 DEG C₃The cost is low, the preparation is simple, but the HCN treatment effect is higher and NH is higher under the water-containing condition₃Lower catalytic activity, phaseNH under anhydrous condition₃High conversion efficiency and low catalytic activity of HCN, so that the method cannot be applied to HCN and NH₃While removing it.

Therefore, the development of a catalyst capable of efficiently catalytically oxidizing NH under the same reaction conditions₃And HCN are necessary.

Disclosure of Invention

The invention aims to provide a catalyst capable of simultaneously removing hydrogen cyanide and ammonia gas, and a preparation method and application thereof₃。

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a preparation method of a catalyst capable of removing hydrogen cyanide and ammonia gas simultaneously, which comprises the following steps:

soaking the carrier in a first metal precursor aqueous solution for first stirring, then carrying out first rotary evaporation to remove moisture in the obtained mixed material, drying, and carrying out first roasting to obtain a first intermediate product;

dipping the first intermediate product into a second metal precursor aqueous solution for second stirring, then performing second rotary evaporation to remove moisture in the obtained material, drying, and performing second roasting to obtain a second intermediate product;

reducing the second intermediate product to obtain a catalyst capable of removing hydrogen cyanide and ammonia gas simultaneously;

the carrier is TiO₂Nano gamma-Al₂O₃、CeO₂One or more of ZSM-5, SAPO-34, SSZ-13 and Y-zeolite;

the metal in the first metal precursor aqueous solution and the second metal precursor aqueous solution is independently Cu, Fe, Mn, Ag, Co or Ni.

Preferably, the mass of the first metal in the first metal precursor aqueous solution and the mass of the second metal in the second metal precursor aqueous solution are independently 1 to 20% of the mass of the support.

Preferably, the temperature of the first roasting and the second roasting is independently 500-550 ℃, and the roasting time is independently 1-7 h.

Preferably, the first stirring and the second stirring are carried out at room temperature, and the time of the first stirring and the time of the second stirring are independently 2-12 h.

Preferably, the reduction treatment is performed in a mixed gas of hydrogen and nitrogen, and the hydrogen accounts for 10% by volume of the mixed gas.

Preferably, the temperature of the reduction treatment is 400-700 ℃, and the time is 1-4 h.

Preferably, the temperature of the first rotary evaporation and the temperature of the second rotary evaporation are 65-95 ℃ independently.

The invention provides a catalyst which is prepared by the preparation method in the scheme and can simultaneously remove hydrogen cyanide and ammonia gas, comprising a carrier and active components, wherein the active components are positioned in hydroxyl positions and pore channels of the carrier; the active component includes a first metal and a second metal; the particle size of the second metal is larger than that of the first metal; the first metal and the second metal are independently Cu, Fe, Mn, Ag, Co or Ni; the carrier is TiO₂Nano gamma-Al₂O₃、CeO₂One or more of ZSM-5, SAPO-34, SSZ-13 and Y-zeolite.

The invention provides application of the catalyst capable of simultaneously removing hydrogen cyanide and ammonia gas in the scheme in treatment of tail gas containing hydrogen cyanide and/or ammonia gas, and the application is carried out under anhydrous conditions.

Preferably, the method of application comprises: the catalyst is placed in a fixed bed, the fixed bed containing the catalyst is placed in tail gas containing hydrogen cyanide and/or ammonia gas for reaction, and the reaction temperature is 150-500 ℃.

The invention provides a preparation method of a catalyst capable of removing hydrogen cyanide and ammonia gas simultaneously, which comprises the following steps: soaking the carrier in a first metal precursor aqueous solution for first stirring, then carrying out first rotary evaporation to remove moisture in the obtained mixed material, drying, and carrying out first roasting to obtain a first intermediate product; immersing the first intermediate product in a second metal precursor aqueous solutionSecondly, stirring, then carrying out second rotary evaporation to remove moisture in the obtained material, drying, and carrying out second roasting to obtain a second intermediate product; reducing the second intermediate product to obtain a catalyst capable of removing hydrogen cyanide and ammonia gas simultaneously; the carrier is TiO₂Nano gamma-Al₂O₃、CeO₂One or more of ZSM-5, SAPO-34, SSZ-13 and Y-zeolite; the metal in the first metal precursor aqueous solution and the second metal precursor aqueous solution is independently Cu, Fe, Mn, Ag, Co or Ni.

The invention uses inorganic metal oxide or molecular sieve rich in hydroxyl as carrier, the number of hydroxyl directly determines the dispersibility of active metal and the particle size after reduction, and the first metal replaces a large number of hydroxyl to be loaded on the surface of the carrier through first impregnation and first roasting, at the moment, the first metal is in a state with high dispersibility and mostly exists in a metal monatomic oxide (namely, the active metal replaces hydroxyl to form [ active metal atom-O-carrier with other atoms except oxygen)]Form (e), a state in which no cluster is formed), the formation of metal oxide clusters is also small; when the second metal is loaded, the carrier does not have enough abundant hydroxyl, so that the second roasting process can agglomerate into larger metal oxide in the microporous structure of the carrier, the dispersion degrees of the two metals are different, and finally, through reduction treatment, most of the first metal monatomic oxide and the second metal oxide can be reduced into metal simple substances, but the different dispersion degrees can cause different particle sizes of successively loaded metal simple substance particles, and the different particle sizes are different for NH₃Different from the adsorption capacity and the oxygen activation capacity of HCN, the metal elementary substance particles of the active component have different particle sizes, so that the catalyst can adsorb NH₃The HCN and the HCN have good adsorption capacity and higher oxygen activating capacity, so that the HCN and the NH can be adsorbed under the same condition₃Efficient removal of the active species. The invention activates O by active metal₂Forming active oxygen with high activity, and further reacting with HCN and NH₃The reaction achieves conversion of both species.

The catalyst prepared by the invention can simultaneously remove HCN and NH in various industrial tail gases₃Reacting HCN and NH₃Oxidation to water and N₂At the maximum space velocity of 64200h^-1Achieves 95 percent of HCN conversion rate and 100 percent of NH₃Conversion, N₂The selectivity can reach 95 percent.

In addition, the catalyst can be obtained only by dipping and simple roasting, and the method is simple and easy to implement; according to the invention, the inorganic metal oxide or molecular sieve rich in hydroxyl is used as a carrier, the cheap metal is used as an active component, and all reagent materials are relatively cheap in the preparation process of the catalyst, so that the preparation cost is low; the catalyst can remove HCN and NH simultaneously₃In addition, it can also be in NH₃Or tail gas with independent HCN exists is used, and the application range is wide.

Drawings

FIG. 1 shows the reaction temperature of the catalyst prepared in example 1 for HCN and NH₃The conversion curve of (a);

FIG. 2 is a graph showing the effect of catalysts prepared by different carriers on ammonia removal.

Detailed Description

In the present invention, the starting materials used are all commercially available products well known in the art, unless otherwise specified.

The method comprises the steps of immersing a carrier in a first metal precursor aqueous solution for first stirring, then removing moisture in the obtained mixed material through first rotary evaporation, drying, and performing first roasting to obtain a first intermediate product.

In the present invention, the carrier is TiO₂Nano gamma-Al₂O₃、CeO₂One or more of ZSM-5, SAPO-34, SSZ-13 and Y-zeolite, preferably nano gamma-Al₂O₃. The invention takes the oxide or the molecular sieve rich in hydroxyl as the carrier of the active component, because the hydroxyl number directly determines the dispersibility and the reduced particle size of the active metal, the more the hydroxyl number of the carrier is rich, the higher the catalyst performance is, thus the nanometer gamma-Al rich in hydroxyl₂O₃Is the best carrier.

In the present invention, the first metal in the first metal precursor aqueous solution is preferably Cu, Fe, Mn, Ag, Co, or Ni, and more preferably Ag. The first metal precursor is not particularly limited in kind as long as it is completely soluble in water, such as nitrate, sulfate or chloride, and preferably nitrate of the first metal. In the invention, when the nitrate of the first metal is adopted as the first metal precursor, the catalytic performance of the obtained catalyst is better.

The concentration of the first metal precursor aqueous solution is not particularly required, and any concentration can be adopted, and a saturated solution is preferred. The invention has no special requirement on the dosage of the first metal precursor aqueous solution, and can completely immerse the carrier.

In the present invention, the mass of the first metal in the first metal precursor aqueous solution is preferably 1 to 20% of the mass of the support, more preferably 5 to 15%, even more preferably 7 to 12%, and most preferably 10%.

In the present invention, the first stirring is preferably performed at room temperature, and the time of the first stirring is preferably 1 to 12 hours, such as 1 hour, 2 hours, 4 hours, 6 hours, 8 hours, 10 hours or 12 hours, and preferably 2 hours. The rate of the first agitation is not particularly critical to the present invention and may be any rate known in the art.

The invention utilizes the first stirring to realize the full mixing of the carrier and the first metal ions.

After the first stirring is finished, the method carries out first rotary evaporation, removes water in the obtained mixed material, and then carries out drying.

In the invention, the temperature of the first rotary evaporation is preferably 65-95 ℃, more preferably 70-90 ℃, and most preferably 80 ℃. In the invention, the drying temperature is preferably 90-110 ℃, and more preferably 105 ℃; the drying time is preferably 6-12 h, and more preferably 10 h.

After the drying is finished, the invention carries out first roasting on the obtained dried material to obtain a first intermediate product. In the invention, the temperature of the first roasting is preferably 500-550 ℃, and more preferably 550 ℃; the roasting time is preferably 1-7 h, and more preferably 3 h. In the present invention, the first firing is preferably performed in an air atmosphere. The temperature of the invention is preferably raised from room temperature to the temperature of the first calcination, and the temperature raising rate is preferably 0.5 ℃/min. In the first roasting process, the crystal form of the carrier grows, and meanwhile, first metal ions fully mixed with the carrier replace hydroxyl hydrogen to form an X-O-M structure linked on the carrier, so that the load of the active metal is realized, wherein X is a first metal atom, M is other atoms except oxygen of the carrier, generally is a carrier metal atom, such as nano gamma-Al₂O₃On the surface of which an X-O-Al structure is formed, on the TiO₂The structure of X-O-Ti is formed, and the structures of X-O-Al and X-O-Si are formed on ZSM-5.

After the first intermediate product is obtained, the first intermediate product is soaked in a second metal precursor aqueous solution for second stirring, then the moisture in the obtained material is removed through second rotary evaporation, and the second intermediate product is obtained through drying and second roasting.

In the present invention, the second metal in the second metal precursor aqueous solution is preferably Cu, Fe, Mn, Ag, Co, or Ni, and more preferably Cu. In the invention, the first metal is Ag, and the second metal is Cu, so that the effect of removing hydrogen cyanide and ammonia gas is better.

The second metal precursor is not particularly limited in kind as long as it is completely soluble in water, such as nitrate, sulfate or chloride, and preferably nitrate of the second metal. In the invention, when the second metal precursor adopts the nitrate of the second metal, the catalytic performance of the obtained catalyst is better.

The concentration of the second metal precursor aqueous solution is not particularly required, and any concentration can be adopted, and a saturated solution is preferred. The invention has no special requirement on the dosage of the second metal precursor aqueous solution, and the first intermediate product can be completely immersed.

In the present invention, the mass of the second metal in the second metal precursor aqueous solution is preferably 1 to 20% of the mass of the support, more preferably 5 to 15%, even more preferably 7 to 12%, and most preferably 10% of the mass of the support, based on the mass of the support used for preparing the first intermediate product.

In the present invention, the second stirring condition is the same as the first stirring condition, and is not described herein again. The invention utilizes the second stirring to realize the full mixing of the second metal ions and the first intermediate.

After the second stirring is finished, the method carries out second rotary evaporation, removes the moisture in the obtained material and then carries out drying.

In the present invention, the conditions of the second rotary evaporation are the same as the conditions of the first rotary evaporation, and the drying conditions are the same as the drying conditions after the first rotary evaporation, which are not described herein again.

After the drying is finished, the product obtained by drying is subjected to second roasting to obtain a second intermediate product.

In the present invention, the conditions of the second firing are the same as those of the first firing. Because a large amount of hydroxyl groups on the carrier are occupied by the first metal after the first roasting, the first metal cannot be changed in the second roasting process, and the second metal cannot be connected with the carrier due to insufficient hydroxyl point positions, so that the second metal ions start to agglomerate to form large-particle metal oxides to stay in microchannels of the carrier, and the dispersion degree of the second metal compared with the first metal is greatly reduced.

After the second intermediate product is obtained, the second intermediate product is subjected to reduction treatment to obtain the catalyst capable of simultaneously removing hydrogen cyanide and ammonia gas.

In the present invention, the reduction treatment is preferably performed in a mixed gas of hydrogen and nitrogen, and the hydrogen is preferably 10% by volume of the mixed gas. In the invention, the temperature of the reduction treatment is preferably 400-700 ℃, more preferably 550-650 ℃, and most preferably 600 ℃; the time of the reduction treatment is preferably 1 to 4 hours, and more preferably 2 to 3 hours.

In the reduction treatment process, the monatomic oxide of the first metal is gathered and releases hydroxyl, the adsorption capacity to ammonia is enhanced due to the increase of hydroxyl sites, meanwhile, most of the monatomic oxide of the first metal and the oxide of the second metal are reduced into metal simple substance particles, only a small part of the first metal existing in the monatomic form and the oxide of the second metal exist in the finally reduced catalyst, the rest are metal simple substance particles with a certain particle size, and the simple substance particles of the second metal are larger than the simple substance particles of the first metal.

The invention provides a catalyst which is prepared by the preparation method in the scheme and can simultaneously remove hydrogen cyanide and ammonia gas, comprising a carrier and active components, wherein the active components are positioned in hydroxyl positions and pore channels of the carrier; the active component includes a first metal and a second metal; the particle size of the second metal is larger than that of the first metal; the first metal and the second metal are independently Cu, Fe, Mn, Ag, Co or Ni; the carrier is TiO₂Nano gamma-Al₂O₃、CeO₂One or more of ZSM-5, SAPO-34, SSZ-13 and Y-zeolite. In the present invention, the support is preferably nano γ -Al₂O₃The first metal is preferably Ag, and the second metal is preferably Cu. In the invention, the first metal is specifically positioned at the hydroxyl sites of the carrier, and a small part of the second metal is positioned at the hydroxyl sites of the carrier and a large part of the second metal is positioned in the pore channels of the carrier.

The first metal and the second metal simple substance particles have different particle sizes, and the different particle sizes are used for NH₃Different from the adsorption capacity and the oxygen activation capacity of HCN, the metal elementary substance particles of the active component have different particle sizes, so that the catalyst can adsorb NH₃The HCN and the HCN have good adsorption capacity and higher oxygen activating capacity, so that the HCN and the NH can be adsorbed under the same condition₃Efficient removal of the active species. The invention activates O by active metal₂Forming active oxygen with high activity, and further reacting with HCN and NH₃The reaction achieves conversion of both species.

According to the catalyst, the first metal and the second metal simple substance particles have strong oxygen binding capacity, and the bound oxygen can be combined with H (hydrogen cyanide) removed to form water, so that metal atoms on the surfaces of the metal particles are always circulated between the simple substances and the metal oxide substances, and the catalyst is always stable.

In the present invention, the method of application preferably comprises: the catalyst is placed in a fixed bed, and the fixed bed containing the catalyst is placed in tail gas containing hydrogen cyanide and/or ammonia gas for reaction.

In the invention, the particle size of the catalyst is preferably 40-60 meshes. The fixed bed is not particularly limited in the present invention, and a fixed bed known in the art may be used.

The invention has no special requirements on the concentration of hydrogen cyanide and ammonia gas in the tail gas, and the concentration is uniform at will. In the embodiment of the invention, the concentration of HCN in the tail gas is 200ppm (the state requires 200ppm of upper limit of the concentration of HCN gas for experiment), and the concentration of ammonia in the tail gas is 500 ppm.

In the invention, the reaction temperature is preferably 150-500 ℃, more preferably 225-450 ℃, more preferably 250-350 ℃, and most preferably 250 ℃; the volume space velocity of the reaction is preferably 118000h^-1. In the present invention, O is preferably used₂And N₂The mixed gas of (1) as an equilibrium atmosphere, the mixed gas containing O₂The content of (b) is preferably 10% by volume.

The catalyst capable of removing hydrogen cyanide and ammonia gas simultaneously provided by the present invention, and the preparation method and application thereof are described in detail below with reference to examples, but they should not be construed as limiting the scope of the present invention.

Example 1

Taking 10g of nano gamma-Al₂O₃With saturated AgNO₃Mixing the solutions to make the atomic mass of the loaded Ag be 1g, stirring the mixed suspension for 2h at room temperature, performing first rotary evaporation at 65 ℃ to remove excessive water, drying at 105 ℃ for 10h, performing first roasting on the obtained sample at 550 ℃ in air atmosphere for 3h to obtain a first intermediate product which is Ag/Al₂O₃；

Mixing the first intermediate product with saturated Cu (NO)₃)₂Mixing the solutions to make the added Cu atomic mass be 1g, stirring the mixed suspension for 2h at room temperature, performing second rotary evaporation at 65 ℃ to remove excessive water, drying at 105 ℃ for 10h, performing second roasting on the obtained sample at 550 ℃ in air atmosphere for 3h to obtain a second intermediate product, namely Ag-Cu/Al₂O₃；

The second intermediate product is reacted in H₂And N₂Mixed atmosphere (H)₂ Volume content 10%) for 2h at a temperature of 600 deg.c, to complete the preparation of the desired catalyst.

Example 2

Taking 20g of nano gamma-Al₂O₃With saturated AgNO₃Mixing the solutions to make the atomic mass of the loaded Ag be 2g, stirring the mixed suspension for 3h at room temperature, performing first rotary evaporation at 85 ℃ to remove excessive water, drying at 105 ℃ for 10h, performing first roasting on the obtained sample at 500 ℃ in air atmosphere for 3h to obtain a first intermediate product which is Ag/Al₂O₃；

Will be prepared into the firstIntermediate product and saturated Cu (NO)₃)₂Mixing the solutions to make the added Cu atomic mass be 1g, stirring the mixed suspension for 2h at room temperature, performing second rotary evaporation at 65 ℃ to remove excessive water, drying at 105 ℃ for 10h, performing second roasting on the obtained sample at 500 ℃ in air atmosphere for 3h to obtain a second intermediate product, namely Ag-Cu/Al₂O₃；

Example 3

Taking 20g of nano gamma-Al₂O₃With saturated AgNO₃Mixing the solutions to make the atomic mass of the loaded Ag be 4g, stirring the mixed suspension for 3h at room temperature, performing first rotary evaporation at 85 ℃ to remove excessive water, drying at 105 ℃ for 10h, performing first roasting on the obtained sample at 500 ℃ in air atmosphere for 4h to obtain a first intermediate product, namely Ag/Al₂O₃；

Mixing the first intermediate product with saturated Cu (NO)₃)₂Mixing the metal precursor solutions to enable the added Cu atomic mass to be 1g, stirring the mixed suspension for 2h at room temperature for the second time, performing second rotary evaporation at 85 ℃ to remove excessive water, drying at 105 ℃ for 10h, performing second roasting on the obtained sample at 500 ℃ in an air atmosphere for 4h to obtain a second intermediate product, namely Ag-Cu/Al₂O₃；

Example 4

Taking 20g of nano gamma-Al₂O₃With AgNO₃Mixing the solutions until the mass of Ag atom is 4g, stirring the mixed suspension at room temperature for 5 hr, and removing by rotary evaporation at 85 deg.CDrying the sample at 105 ℃ for 12h after excessive moisture is removed, and roasting the sample at 500 ℃ for 4h in an air atmosphere to obtain a first intermediate product, namely Ag/Al₂O₃；

Mixing the first intermediate product with saturated Cu (NO)₃)₂Mixing the solutions to make the added Cu atomic mass be 0.5g, stirring the mixed suspension for 2h at room temperature, performing second rotary evaporation at 85 ℃ to remove excessive water, drying at 105 ℃ for 10h, performing second roasting on the obtained sample at 500 ℃ in air atmosphere for 4h to obtain a second intermediate product, namely Ag-Cu/Al₂O₃；

The second intermediate product is reacted in H₂And N₂Mixed atmosphere (H)₂ Volume content 10%) for 2h at a temperature of 700 deg.c, to complete the preparation of the desired catalyst.

Comparative example 1

The difference from the embodiment 1 is that only one-time load is adopted, and the specific steps are as follows:

10g of nano gamma-Al is taken₂O₃Saturated AgNO₃Solution with saturated Cu (NO)₃)₂Mixing the solutions to ensure that the atomic mass of the loaded Ag is 1g and the atomic mass of the added Cu is 1g, stirring the mixed suspension for 2h at room temperature for the first time, then drying the suspension at 105 ℃ for 10h after removing excessive water through the first rotary evaporation at 65 ℃, and roasting the dried sample for 3h at 550 ℃ in an air atmosphere to obtain a first intermediate product, namely Ag-Cu/Al₂O₃；

The first intermediate product is reacted in H₂And N₂Mixed atmosphere (H)₂ Volume content 10%) for 2h at a temperature of 600 deg.c, to complete the preparation of the desired catalyst.

And (3) performance testing:

1. the catalyst prepared in example 1 was used for the treatment of a catalyst containing both HCN and NH₃In which the concentration of HCN is 100ppm, NH₃The concentration of (2) was 500 ppm.

The reaction conditions are as follows: o is₂And N₂As an equilibrium atmosphere (wherein O is contained in the mixed gas)₂Volume content of 10%) and a volume space velocity of 118000h^-1The reaction temperatures were 100 ℃, 125 ℃, 150 ℃, 175 ℃, 200 ℃, 225 ℃, 250 ℃, 275 ℃ and 300 ℃ respectively, and the results are shown in FIG. 1.

As can be seen from FIG. 1, the catalyst prepared in example 1 was able to treat about 95% HCN and 80% NH at 225 deg.C₃For simultaneous removal of HCN and NH₃Has good treatment effect.

Whereas the catalyst prepared in comparative example 1 was exposed to HCN and NH at 225 ℃ under the same conditions₃The removal rates of (A) and (B) are 40% and 100%, respectively, only for NH₃Has higher removal rate, which shows that the invention can realize the reaction of HCN and NH under the same condition by secondary load roasting₃While at the same time removing efficiently.

2. Screening of nano gamma-Al₂O₃And micron gamma-Al₂O₃The preparation of the catalyst is carried out by adopting the following methods respectively as a carrier: taking 10g of carrier and saturated AgNO₃Mixing the solutions until the atomic mass of Ag is 1g, stirring the mixed suspension at room temperature for 3h, rotary evaporating at 85 deg.C to remove excessive water, drying at 105 deg.C for 10h, and calcining the dried sample at 500 deg.C in air atmosphere for 4h to obtain Ag/Al₂O₃(ii) a Mixing Ag with Al₂O₃In H₂And N₂Mixed atmosphere (H)₂Volume content of 10%) at 500 deg.C for 2 hr.

The two catalysts obtained are used for treating NH-containing₃Tail gas of (1), NH in the tail gas₃The concentration of (B) is 500 ppm; the reaction conditions are as follows: o is₂And N₂As an equilibrium atmosphere (wherein O is contained in the mixed gas)₂Volume content of 10%) and a volume space velocity of 118000h^-1。

FIG. 2 is a diagram showing the effect of catalysts prepared by different carriers on removing ammonia, and it can be seen from FIG. 2 that nano gamma-Al₂O₃Relatively micron gamma-Al₂O₃The catalyst prepared by the catalyst as a carrier has better catalytic performance.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. the application of a catalyst capable of simultaneously removing hydrogen cyanide and ammonia in processing the tail gas containing hydrogen cyanide and ammonia, and the application is carried out under anhydrous conditions;

The catalyst capable of removing hydrogen cyanide and ammonia at the same time includes a carrier and an active component, and the active component is located in the hydroxyl site and pores of the carrier; the active component includes a first metal and a second metal The particle size of the second metal is larger than the particle size of the first metal; the first metal is Ag; the second metal is Cu; the carrier is nano-γ-Al ₂ O ₃ ;

The preparation method of the catalyst capable of simultaneously removing hydrogen cyanide and ammonia, the specific steps are:

The carrier is immersed in the first metal precursor aqueous solution for the first stirring, and then the moisture in the obtained mixture is removed by the first rotary distillation, dried, and subjected to the first roasting to obtain the first intermediate product;

The first intermediate product is immersed in the second metal precursor aqueous solution for a second stirring, and then the moisture in the obtained material is removed by the second rotary distillation, dried, and subjected to a second roasting to obtain a second intermediate product;

The second intermediate product is subjected to reduction treatment to obtain a catalyst capable of simultaneously removing hydrogen cyanide and ammonia;

The carrier is nano-γ-Al ₂ O ₃ ;

The metal in the first metal precursor aqueous solution is Ag; the metal in the second metal precursor aqueous solution is Cu.

2. application according to claim 1, is characterized in that, the method for described application comprises: catalyzer is placed in fixed bed, the fixed bed filled with catalyzer is placed in the tail gas containing hydrogen cyanide and ammonia to carry out reaction, the temperature of the reaction is 150 ~ 500 ℃.

3. The application according to claim 1, wherein the mass of the first metal in the first aqueous solution of metal precursor and the mass of the second metal in the aqueous solution of the second metal precursor are independently 1～1 of the mass of the carrier 20%.

4 . The application according to claim 1 , wherein the temperature of the first roasting and the second roasting is independently 500-550° C., and the roasting time is independently 1-7 h. 5 .

5 . The application according to claim 1 , wherein the first stirring and the second stirring are carried out at room temperature, and the time of the first stirring and the second stirring is independently 2 to 12 h. 6 .

6 . The application according to claim 1 , wherein the reduction treatment is carried out in a mixed gas of hydrogen and nitrogen, and the volume percentage of the hydrogen in the mixed gas is 10%. 7 .

7 . The application according to claim 1 , wherein the temperature of the reduction treatment is 400-700° C., and the time is 1-4 h. 8 .

8 . The application according to claim 1 , wherein the temperature of the first rotary steam and the second rotary steam is independently 65 to 95° C. 9 .