CN113877604A

CN113877604A - Catalyst for purifying waste gas containing bromine-containing organic matter, preparation method thereof and method for purifying waste gas containing bromine-containing organic matter

Info

Publication number: CN113877604A
Application number: CN202010628921.8A
Authority: CN
Inventors: 蒋见; 缪长喜; 卢媛娇; 孙清; 张磊; 张新玉
Original assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Current assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Priority date: 2020-07-01
Filing date: 2020-07-01
Publication date: 2022-01-04
Anticipated expiration: 2040-07-01
Also published as: CN113877604B

Abstract

The invention relates to the technical field of catalytic combustion and environmental protection, and discloses a catalyst for purifying waste gas containing bromine-containing organic matters, a preparation method thereof and a method for purifying the waste gas containing the bromine-containing organic matters, wherein the catalyst comprises an integral carrier containing an alumina coating, and a noble metal active component and a non-noble metal active component which are loaded on the integral carrier; wherein the non-noble metal active component is a composite oxide containing cobalt oxide and manganese oxide and/or titanium oxide; the molar ratio of Co to Mn in the composite oxide is 3-15: 1, and/or the molar ratio of Co to Ti is 1 to 8: 1. the catalyst prepared by the method has higher halogen toxicity resistance and stability, is used for purifying waste gas containing bromine-containing organic matters, and still has higher catalytic activity and selectivity at lower reaction temperature.

Description

Catalyst for purifying waste gas containing bromine-containing organic matter, preparation method thereof and method for purifying waste gas containing bromine-containing organic matter

Technical Field

The invention relates to the technical field of catalytic combustion and environmental protection, in particular to a catalyst for purifying waste gas containing bromine-containing organic matters, a preparation method thereof and a method for purifying waste gas containing bromine-containing organic matters.

Background

Petrochemical production processes often produce waste gases containing volatile organic compounds, which if discharged directly into the atmosphere, can cause significant damage to the atmospheric environment. Most volatile organic compounds have peculiar smell and cause pathological changes and even carcinogenesis to human bodies; in particular, the volatile organic waste gas containing halogen has high toxicity, and can generate photochemical reaction with ozone to generate photochemical smog, thereby greatly damaging the global environment.

The domestic and foreign treatment methods for volatile organic compounds are mainly classified into physical methods and chemical methods. The physical methods include an adsorption method, a condensation method, a membrane separation method and the like, and have the advantages that volatile organic compounds can be recycled, but the treatment is not thorough, and secondary pollution is easily caused. The chemical method mainly comprises a direct thermal combustion method, a catalytic combustion method and the like, and is characterized in that the treatment is thorough; however, the thermal combustion method cracks the harmful substances in the tail gas at high temperature, the thermal cracking temperature is as high as 800-. The catalytic combustion method can reduce the operation temperature by means of the catalyst, greatly reduce the energy consumption, ensure safe and stable operation, reduce the operation cost and avoid generating nitrogen oxides, thereby avoiding secondary pollution. Therefore, the catalytic combustion method is an ideal method for treating petrochemical organic waste gas.

The catalysts used in the current catalytic combustion method mainly comprise: noble metal type catalysts, such as Pt, Pd, Rh, etc., which have high activity but poor halogen resistance and are easy to be poisoned, resulting in poor stability, and meanwhile, the resources are rare and the price is expensive; single metal oxide catalysts, such as copper, manganese, cobalt and other metal oxides, are relatively low in cost but generally active; the composite oxide catalyst is not easy to poison and has higher catalytic activity than that of a corresponding single oxide, for example, CN103252242B discloses a catalytic combustion catalyst of a composite oxide of copper, manganese and cerium, but the reaction temperature is still higher, and the catalyst activity is also to be improved.

Disclosure of Invention

The invention aims to overcome the problems of poor toxicity resistance and low catalytic activity of the catalyst in the prior art, and provides a catalyst for purifying waste gas containing bromine-containing organic matters, a preparation method thereof and a method for purifying the waste gas containing the bromine-containing organic matters.

In order to achieve the above object, the present invention provides a catalyst for purifying an exhaust gas containing a bromine-containing organic compound, the catalyst comprising a monolith support containing an alumina coating layer, and a noble metal active component and a non-noble metal active component supported on the monolith support;

wherein the non-noble metal active component is a composite oxide containing cobalt oxide and manganese oxide and/or titanium oxide;

the molar ratio of Co to Mn in the composite oxide is 3-15: 1, and/or the molar ratio of Co to Ti is 1 to 8: 1.

In a second aspect of the present invention, there is provided a method for preparing a catalyst for purifying an exhaust gas containing a bromine-containing organic substance, the method comprising:

(1) coating the slurry containing the alumina and/or the alumina precursor on the monolithic carrier, and then drying and/or roasting to obtain the monolithic carrier containing the alumina coating;

(2) loading a composite oxide containing cobalt oxide and manganese oxide and/or titanium oxide and a noble metal active component on an alumina-coated monolithic carrier;

wherein the molar ratio of Co to Mn in the composite oxide is 3-15: 1, and/or the molar ratio of Co to Ti is 1 to 8: 1.

in a third aspect, the present invention provides a catalyst prepared by the preparation method described in the second aspect.

In a fourth aspect of the present invention, there is provided a method for purifying an exhaust gas containing a bromine-containing organic substance, comprising catalytically combusting an exhaust gas containing a bromine-containing organic substance in contact with the catalyst of the first or third aspect in an oxygen-containing atmosphere.

The catalyst prepared by the technical scheme of the invention can catalyze the waste gas containing bromine-containing organic matters to perform catalytic combustion reaction at a lower reaction temperature, and still can obtain higher conversion rate and CO₂And the selectivity shows that the catalyst has higher catalytic activity and selectivity, and still has higher catalytic activity and selectivity when the catalytic combustion reaction is carried out for 1000h, thus the catalyst has higher stability and higher halogen toxicity resistance.

Drawings

Fig. 1 is a raman spectrum of the composite oxide prepared in example 2;

fig. 2 is a raman spectrum of the composite oxide prepared in example 5;

fig. 3 is a raman spectrum of the composite oxide prepared in example 7;

fig. 4 is a raman spectrum of the composite oxide prepared in comparative example 5;

fig. 5 is a raman spectrum of the composite oxide prepared in comparative example 6.

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

The inventor of the invention discovers through research that under the condition that Co and Mn and/or Ti exist in a specific ratio in the composite oxide, the composite oxide containing cobalt oxide, manganese oxide and/or titanium oxide, the noble metal active component and the monolithic carrier containing an alumina coating can generate synergistic effect, can obviously improve the halogen toxicity resistance and stability of the catalyst, and has excellent catalytic activity and selectivity at a lower reaction temperature in the treatment of the exhaust gas containing bromine-containing organic matters.

In a first aspect, the present invention provides a catalyst for purifying exhaust gas containing bromine-containing organic compounds, the catalyst comprising a monolithic carrier containing an alumina coating layer and a noble metal active component and a non-noble metal active component supported on the monolithic carrier;

The composite oxide may contain cobalt oxide and manganese oxide, may contain cobalt oxide and titanium oxide, and may contain both cobalt oxide and manganese oxide and titanium oxide. According to the present invention, preferably, the non-noble metal active component is a composite oxide containing cobalt oxide, manganese oxide and titanium oxide. It is more advantageous to use this preferred embodiment to further improve the halogen toxicity resistance, catalytic activity, selectivity and stability of the catalyst.

In the present invention, "the molar ratio of Co to Mn in the composite oxide is 3 to 15: 1, and/or the molar ratio of Co to Ti is 1 to 8: 1' indicates that, when Mn is contained in the composite oxide, the molar ratio of Co to Mn is 3 to 15: 1; when the composite oxide contains Ti, the molar ratio of Co to Ti is 1-8: 1 does not mean that Mn and Ti are always contained in the composite oxide at the same time.

According to the present invention, in order to further improve the halogen toxicity resistance, catalytic activity, selectivity and stability of the catalyst, it is preferable that the molar ratio of Co to Mn in the composite oxide is 3.5 to 14.5: 1, preferably 6 to 12: 1.

according to the present invention, preferably, the molar ratio of Co to Ti in the composite oxide is 1.5 to 7.5: 1, preferably 3 to 6: 1.

according to the present invention, the amount of the non-noble metal active component supported on an oxide basis is preferably 30 to 150g (for example, 30g, 40g, 50g, 60g, 70g, 80g, 90g, 100g, 110g, 120g, 130g, 140g, and 150g, or any value therebetween) with respect to 1L of the monolithic support, more preferably 35 to 140g, and still more preferably 60 to 120 g.

According to the present invention, it is preferable that 615-725cm in the Raman spectrum of the composite oxide in the catalyst^-1The peak intensity at the position is higher than 175-230cm^-1Peak intensity at position 175-^-1The peak intensity at the position is higher than 450-^-1Peak intensity at position and 475-^-1Peak intensity at location. The catalyst with the Raman spectrum peak intensity in the preferred case has better catalytic performance and anti-halogen toxicity capability. Co in the prior art₃O₄Respectively at 689cm in Raman spectrum^-1，619cm^-1，521cm^-1And 481cm^-1A peak appears at a position of 689cm^-1Peak intensity at position higher than 521cm^-1And 481cm^-1Peak intensity at position 521cm^-1And 481cm^-1Peak intensity at position higher than 619cm^-1Peak intensity at location.

According to the present invention, the loading amount of the noble metal active component can be selected in a wide range, and in order to further improve the halogen toxicity resistance, catalytic activity, selectivity and stability of the catalyst, it is preferable that the loading amount of the noble metal active component is 100-.

According to the present invention, preferably, the noble metal is selected from at least one of Au, Ag, Pt, Pd, Ru, Rh, Os, and Ir.

More preferably, the noble metal is Pt and/or Pd.

More preferably, the noble metals are Pt and Pd.

Further preferably, the molar ratio of Pt and Pd in the noble metal active component is 0.01 to 10: 1, more preferably 0.05 to 5: 1, more preferably 0.1 to 0.5: 1. the Pt and Pd in the optimal proportion are matched, so that the catalytic performance of the catalyst is improved.

According to the present invention, in order to further increase the number of channels and the specific surface area of the monolithic carrier, thereby further increasing the catalytic activity and selectivity of the catalyst, it is preferable that the content of the alumina coating layer in the monolithic carrier is 5 to 20% by weight, preferably 7 to 15% by weight.

According to the present invention, the monolith support has a general illustration in the art, and preferably, the monolith support is selected from monolith supports having a parallel channel structure with both ends open.

According to the present invention, the porosity of the monolithic support in cross section can be selected within a wide range, preferably the porosity of the monolithic support in cross section is in the range of 30 to 90%, preferably 45 to 75%. The porosity of the cross section of the monolith support means a ratio of a pore area of the cross section of the monolith support to the entire cross sectional area.

According to the present invention, the cross-sectional area of the channels of the monolithic support can be selected within a wide range, and preferably, the cross-sectional area of each channel is 0.5 to 1.5 μm²More preferably 0.7 to 1.3 μm²。

According to the present invention, the kind of the monolith support may be selected from a wide range, and preferably, the monolith support is a ceramic monolith support.

More preferably, the ceramic monolith carrier is at least one selected from the group consisting of a cordierite monolith carrier, a mullite monolith carrier, a zirconia monolith carrier and an alumina monolith carrier, and further preferably a cordierite monolith carrier and/or a mullite monolith carrier.

In a second aspect, the present invention provides a method for preparing a catalyst for purifying an exhaust gas containing a bromine-containing organic substance, the method comprising:

according to the present invention, preferably, the method further comprises: in the step (1), before the slurry containing the alumina and/or the alumina precursor is coated on the monolithic carrier, the slurry containing the alumina and/or the alumina precursor is stirred and colloid-milled. Preferably, the conditions of the stirring include: the stirring time is 0.1-5 hours, and the rotation speed is 200-1500 rpm. Preferably, the conditions of the colloid mill include: the colloid mill time is 0.1-5 hours, and the colloid mill tooth gap size is 0.01-1 mm.

According to the present invention, preferably, the slurry containing alumina and/or an alumina precursor and the monolithic support are used in amounts such that the alumina coating layer content of the monolithic support containing an alumina coating layer obtained in step (1) is 5 to 20% by weight, more preferably 7 to 15% by weight.

According to the present invention, preferably, the alumina and/or alumina precursor-containing slurry contains alumina and/or alumina precursor, water, and optionally pore former, and optionally acid.

According to the invention, preferably, the weight ratio of alumina and/or alumina precursor to water, calculated as alumina, is between 0.05 and 0.8: 1, more preferably 0.3 to 0.7: 1.

the slurry may or may not contain a pore-forming agent, and preferably contains a pore-forming agent. The existence of the pore-forming agent improves the specific surface area of the alumina coating, and is more beneficial to improving the efficiency of catalytic reaction of the catalyst.

According to the invention, the weight ratio of alumina and/or alumina precursor to pore former, calculated as alumina, is preferably 1: 0.3-2.5, more preferably 1: 0.35-1.5.

The slurry may or may not contain an acid, and more preferably contains an acid. The presence of said acid is more advantageous for optimizing the coating effect of the slurry containing alumina.

According to the invention, preferably, the weight ratio of alumina and/or alumina precursor to acid, calculated as alumina, is 1: 0.01 to 0.2, more preferably 1: 0.05-0.15.

According to the present invention, the coating method in the step (1) is not particularly limited as long as the slurry containing alumina can be uniformly adhered to the monolithic support, and is preferably a positive pressure coating method or a negative pressure coating method, and more preferably a negative pressure coating method. The negative pressure coating is performed in a coating machine, and specifically comprises: the alumina-containing slurry at one end of the monolith support is coated onto the monolith support by forming a low pressure environment in a coater. Preferably, the pressure in the coating machine is 0-5 kPa. The negative pressure coating is used in the embodiment of the present invention.

All pressures recited in the present invention are absolute pressures.

According to the present invention, the number of times of coating in step (1) is not particularly limited, and may be one coating or multiple coatings, as long as the required loading amount can be obtained, and the number of times of coating can be specifically selected by those skilled in the art according to actual circumstances.

According to the present invention, the kind of the alumina precursor is not particularly limited, and preferably, the alumina precursor is selected from pseudo-boehmite and/or alumina sol, more preferably pseudo-boehmite.

According to the present invention, the pore-forming agent is not particularly limited in kind as long as it can make the alumina coating layer pore without destroying the whole structure of the alumina coating layer, and preferably, the pore-forming agent is selected from at least one of urea, carboxymethyl cellulose and polyvinyl alcohol, and more preferably urea.

According to the present invention, there is no particular limitation on the kind of the acid, preferably selected from HNO, as long as it can increase the viscosity of the alumina-containing slurry and improve the coating effect₃、H₂SO₄、HCl、CH₃COOH (acetic acid) and H₂C₂O₄At least one of (oxalic acid), more preferably HNO₃。

According to the present invention, there is no particular limitation on the conditions for the drying in step (1), and preferably, the conditions for the drying include: the drying temperature is 80-130 ℃, preferably 100-125 ℃; the drying time is 1-25h, preferably 2-10 h.

More preferably, the drying conditions of step (1) include: heating to the drying temperature from room temperature at the rate of 0.3-0.8 ℃/min for drying.

According to the present invention, preferably, the method further comprises: before the drying in the step (1), the monolithic carrier coated with the slurry containing alumina and/or alumina precursor is purged to remove residual liquid, and then the monolithic carrier is left at room temperature for 5 to 15 hours. There is no particular limitation on the kind of gas used for the purge, such as air, nitrogen, helium, and other inert gases. The purge is usually performed by a high-pressure purge, and the pressure is not particularly limited as long as the residual liquid can be purged.

According to the present invention, the conditions of the calcination in step (1) are not particularly limited, and preferably, the conditions of the calcination in step (1) include: roasting in an oxygen-containing atmosphere, wherein the roasting temperature is 300-600 ℃, and preferably 450-550 ℃; the roasting time is 3-10h, preferably 5-8 h.

More preferably, the roasting conditions of step (1) include: after drying, heating to the roasting temperature at the speed of 0.3-0.8 ℃/min for roasting.

According to the invention, the oxygen content of the oxygen-containing atmosphere may be selected within a wide range, preferably from 5 to 25% by volume.

According to the present invention, preferably, the oxygen containing atmosphere contains oxygen and optionally an inert gas.

According to the present invention, preferably, the inert gas is selected from at least one of nitrogen, helium, neon and argon. It is to be understood that the inert gas according to the present invention refers to a gas that does not participate in the reaction under the firing conditions in the present invention. From an economic point of view, the oxygen-containing atmosphere may be air.

In the step (2) of the present invention, the composite oxide may be loaded on the monolithic carrier with the alumina coating, and then the noble metal active component is loaded, or the noble metal active component may be loaded on the monolithic carrier with the alumina coating, and then the composite oxide is loaded, or the composite oxide and the noble metal active component are loaded on the noble metal active component together. In order to further improve the catalytic performance of the prepared catalyst, preferably, the step (2) comprises the following steps:

(2-1) loading a composite oxide containing cobalt oxide and manganese oxide and/or titanium oxide on an alumina-coated monolithic carrier to obtain a semi-finished catalyst;

(2-2) loading the noble metal active component on the semi-finished product catalyst.

According to the present invention, a particularly preferred embodiment, the step (2-1) supports a composite oxide containing cobalt oxide, manganese oxide and titanium oxide on a monolithic support containing an alumina coating layer.

According to the present invention, preferably, the step (2-1) comprises: coating the slurry containing the composite oxide on an integral carrier containing an alumina coating, and then drying and/or roasting to obtain a semi-finished catalyst; and/or the presence of a gas in the gas,

the step (2-2) comprises: the slurry containing the noble metal source is coated on the semi-finished catalyst and then calcined.

According to the present invention, the manner of coating in step (2-1) is as described above, and will not be described herein.

According to the present invention, the number of times of coating in the step (2-1) is not particularly limited, and may be one coating or multiple coatings, as long as the required loading amount can be obtained, and the number of times of coating can be specifically selected by those skilled in the art according to actual circumstances.

According to the present invention, the solid content of the slurry containing a composite oxide can be selected in a wide range so as to satisfy the coating, and preferably, the solid content of the slurry containing a composite oxide is 10 to 35% by weight, preferably 20 to 30% by weight.

According to the present invention, the slurry containing the composite oxide and the monolithic carrier containing an alumina coating are preferably used in such amounts that the amount of the composite oxide supported in terms of oxide is 30 to 150g, more preferably 35 to 140g, and still more preferably 60 to 120g, relative to 1L of the monolithic carrier containing an alumina coating in the resultant semi-finished catalyst.

According to the present invention, preferably, the drying conditions of step (2-1) include: the drying temperature is 80-130 ℃, and more preferably 100-125 ℃; the drying time is 1-25h, more preferably 2-10 h.

According to the invention, the method further comprises: before the drying in the step (2-1), the monolith type carrier after the slurry containing the composite oxide is coated is purged to remove a residual liquid. The purpose and specific operation of the purge may be as described above and will not be described further herein.

According to the present invention, the conditions for the calcination in step (2-1) can be selected from a wide range, and preferably, the conditions for the calcination in step (2-1) include: in an oxygen-containing atmosphere, the roasting temperature is 300-600 ℃, and more preferably 450-550 ℃; the calcination time is 3 to 10 hours, more preferably 3.5 to 7 hours.

According to the present invention, the molar ratio of Co to Mn and the molar ratio of Co to Ti in the composite oxide are selected within the ranges as described above, and will not be described herein again.

According to the present invention, there is no particular limitation on the method for preparing the composite oxide of step (2), and preferably, the composite oxide of step (2) is prepared by a coprecipitation method.

According to the present invention, preferably, the method for preparing the composite oxide of step (2) comprises: mixing a precursor solution containing cobalt and a precursor solution of manganese and/or titanium with a precipitator for precipitation reaction to obtain a precipitation product, and then drying and roasting the precipitation product.

According to the present invention, in order to enhance the effect of the precipitation reaction, preferably, the method for preparing the composite oxide of step (2) comprises: and (2) adding a precursor solution containing cobalt and a precursor of manganese and/or a precursor of titanium and a precipitator into the reactor in a concurrent flow manner for precipitation reaction, and controlling the pH value of the reaction system in the concurrent flow addition process.

According to the present invention, in order to enhance the effect of the precipitation reaction, preferably, the method for preparing the composite oxide of step (2) further comprises: before mixing the precursor solution containing cobalt and the precursor solution of manganese and/or titanium with the precipitant, colloid milling is performed on the precursor solution containing cobalt and the precursor solution of manganese and/or titanium. Preferably, the conditions of the colloid mill include: the colloid mill time is 10-50min, and the colloid mill tooth gap size is 0.01-1 mm.

According to the present invention, preferably, the precursor solution contains a precursor of cobalt, a precursor of manganese, and a precursor of titanium. The catalytic performance of the catalyst can be further improved with this preferred embodiment.

According to the present invention, there is no particular limitation on the kinds of the cobalt precursor and the manganese precursor as long as they can provide free cobalt ions and manganese ions, and preferably, the cobalt precursor and the manganese precursor are each independently selected from at least one of a nitrate, an acetate, a sulfate, an oxalate, and a halide of a metal, and more preferably, a nitrate.

According to the present invention, the kind of the precursor of titanium is not particularly limited, and preferably, the precursor of titanium is a titanate and/or titanium tetrachloride, more preferably tetraethyl titanate and/or titanium tetrachloride, and still more preferably tetraethyl titanate.

According to the present invention, the kind of the precipitant is not particularly limited as long as it can react with cobalt ions, manganese ions, and titanium ions to generate precipitates, and preferably, the precipitant is selected from at least one of carbonates, bicarbonates, and hydroxides of alkali metals, and more preferably from at least one of sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, and lithium hydroxide.

According to the present invention, preferably, the conditions of the precipitation reaction include: the reaction temperature is 10-90 deg.C (for example, 10 deg.C, 20 deg.C, 30 deg.C, 40 deg.C, 50 deg.C, 60 deg.C, 70 deg.C, 80 deg.C, 90 deg.C, or any value between any two values), more preferably 50-80 deg.C; the pH is 8.5 to 11 (e.g., can be 8.5, 9, 9.5, 10, 10.5, 11, 11.5, or any value in between), and more preferably is 9 to 10.

According to the invention, preferably, stirring can also be carried out during the precipitation reaction. The stirring is advantageous for improving the effect of the precipitation reaction. The stirring rate can be selected within a wide range, and preferably, the stirring rate is 200-1500 rpm.

According to the present invention, the conditions for drying the precipitated product are not particularly limited, and preferably, the conditions for drying the precipitated product include: the drying temperature is 100-120 ℃, and the drying time is 2-8 h.

According to the present invention, conditions for calcining the precipitated product are not particularly limited, and preferably, the conditions for calcining the precipitated product include: in an oxygen-containing atmosphere, the roasting temperature is 400-600 ℃, and more preferably 450-550 ℃; the calcination time is 3 to 8 hours, more preferably 3.5 to 7 hours.

According to the present invention, there is no particular limitation on the method of coating in step (2-2), and preferably, the method of coating is selected from a spray method, a dipping method or a spin coating method, more preferably a dipping method.

According to the present invention, it is preferable that the method of coating the slurry containing the noble metal source on the semi-finished catalyst in the step (2-2) employs an equivalent impregnation method. The preferred equivalent impregnation method is more advantageous in increasing the coating effect and reducing the loss of precious metals.

According to the present invention, the content of the noble metal in the noble metal source-containing slurry is not particularly limited, and preferably, the noble metal content of the noble metal source-containing slurry is 0.05 to 0.5% by weight, preferably 0.1 to 0.35% by weight, in terms of the metal element.

According to the present invention, the amounts of the slurry containing a noble metal source and the semi-finished catalyst to be used may be selected within a wide range, and the amounts of the slurry containing a noble metal source and the semi-finished catalyst to be used are such that the supported amount of the noble metal in the resulting catalyst is 100-2000mg, more preferably 400-800mg, in terms of the metal element, relative to 1L of the monolithic support containing an alumina coating layer.

According to the present invention, preferably, the noble metal source is selected from a precursor of at least one of Au, Ag, Pt, Pd, Ru, Rh, Os, and Ir, more preferably a precursor of Pt and/or a precursor of Pd, and further preferably a precursor of Pt and a precursor of Pd.

Preferably, the precursor of Pt and the precursor of Pd are used in such amounts that the molar ratio of Pt to Pd supported on the surface of the alumina-coated monolithic carrier is 0.01-10: 1, more preferably 0.05 to 5: 1, more preferably 0.1 to 0.5: 1.

according to the invention, the amounts of the Pt precursor and the Pd precursor can be selected within wide limits, preferably the Pt precursor and the Pd precursor are each independently a soluble acid and/or a soluble salt of a metal.

According to the present invention, preferably, the precursor of Pt is selected from at least one of chloroplatinic acid, platinum nitrate and platinum chloride, and more preferably chloroplatinic acid.

According to the present invention, preferably, the precursor of Pd is selected from at least one of palladium nitrate, tetraaminopalladium nitrate and palladium chloride, and more preferably palladium chloride.

According to the present invention, the conditions for the calcination in step (2-2) can be selected from a wide range, and preferably, the conditions for the calcination in step (2-2) include: in an oxygen-containing atmosphere, the roasting temperature is 300-600 ℃, and more preferably 450-550 ℃; the calcination time is 3-10h, more preferably 4-8 h.

According to the present invention, preferably, the method further comprises: in the step (2-2), the slurry containing the noble metal source is coated on the semi-finished catalyst before calcination, and then dried. The drying conditions can be selected within a wide range, and preferably include: the drying temperature is 80-130 ℃, and more preferably 100-125 ℃; the drying time is 1-25h, more preferably 3.5-7 h.

In a third aspect, the present invention provides a catalyst for purifying an exhaust gas containing a bromine-containing organic substance, prepared by the preparation method of the second aspect. The catalyst has high halogen toxicity resistance, and still has high catalytic activity and selectivity at low reaction temperature. The structural composition and component content of the catalyst are as described in the first aspect and will not be described herein.

In a fourth aspect, the present invention provides a method for purifying an exhaust gas containing bromine-containing organic compounds, in which the exhaust gas containing bromine-containing organic compounds is subjected to catalytic combustion in an oxygen-containing atmosphere in contact with the catalyst of the first or third aspect.

Specifically, in the presence of an oxygen-containing atmosphere, waste gas containing bromine-containing organic matters is contacted with a catalyst to be catalytically combusted to generate carbon dioxide and water, and the waste gas also comprises the bromine-containing organic matters to generate hydrogen bromide and/or bromine simple substances.

According to the present invention, preferably, the conditions of the catalytic combustion include: the temperature is 200-450 ℃, and the optimal temperature is 250-400 ℃; volume airspeed3000-30000h^-1Preferably 5000-^-1(ii) a The pressure is 0 to 3MPa, preferably 0 to 2 MPa. The effect of purifying the exhaust gas containing the bromine-containing organic matter can be further improved by adopting the preferable conditions.

In the present invention, the waste gas containing organic bromine compounds may be any industrial waste gas that can be treated by a catalytic combustion method. The invention has wider selection range for the composition of the waste gas containing the bromine-containing organic matters and the content of the bromine-containing organic matters. In the research process, the inventor of the invention finds that the catalyst provided by the invention is particularly suitable for treating waste gas containing bromine-containing organic matters, and is particularly suitable for treating PTA oxidation tail gas.

According to the present invention, the content of the bromine-containing organic substance in the exhaust gas containing the bromine-containing organic substance is preferably 0.1 to 150ppm, more preferably 0.1 to 100ppm, in terms of Br element.

According to the present invention, preferably, the bromine-containing organic matter includes, but is not limited to, at least one of monobromomethane, dibromomethane, monobromoethane, dibromoethane, monobromoethylene and dibromoethylene, more preferably, dibromomethane.

According to a preferred embodiment of the present invention, the exhaust gas containing bromine-containing organic compounds further includes aromatic hydrocarbons and/or ester compounds. The aromatic hydrocarbon includes but is not limited to at least one of benzene, toluene, ethylbenzene, diethylbenzene, xylene, n-propylbenzene and isopropylbenzene, preferably xylene, more preferably p-xylene; the ester compound includes but is not limited to methyl acetate and ethyl acetate, and methyl acetate is preferred.

In the examples of the present invention, methyl acetate, p-xylene, and dibromomethane are exemplified as the off-gas containing the bromine-containing organic matter, and the present invention is not limited thereto.

According to the present invention, the content of oxygen in the oxygen-containing atmosphere may be selected from a wide range as long as it can catalytically combust the exhaust gas containing bromine-containing organic compounds, and in order to further improve the purification effect, it is preferable that the content of oxygen in the oxygen-containing atmosphere is 3 to 100% by volume.

According to the present invention, preferably, the inert gas is selected from at least one of nitrogen, helium, neon and argon. It is to be understood that the inert gas according to the present invention refers to a gas that does not participate in the reaction under the reaction conditions in the present invention.

It will be appreciated by those skilled in the art that the catalyst may be reduced before the catalytic reaction, and the reduction method is not particularly limited and may be a reduction method conventionally used in the art, for example, the reduction method includes: reducing the catalyst for 3-10h at the temperature of 250-350 ℃ in a mixed atmosphere of hydrogen and inert gas. Preferably, the content of hydrogen in the mixed gas of hydrogen and inert gas is 1 to 10% by volume. Preferably, the inert gas is selected from at least one of nitrogen, helium, neon and argon. It is to be understood that the inert gas according to the present invention refers to a gas that does not participate in the reaction under the reducing conditions in the present invention.

The present invention will be described in detail below by way of examples. In the following examples of the present invention,

methyl acetate conversion rate ÷ (amount of unreacted methyl acetate + amount of reacted methyl acetate species) amount of reacted methyl acetate species;

para-xylene conversion ÷ (amount of unreacted para-xylene plus amount of reacted para-xylene);

dibromomethane conversion ═ amount of reacted dibromomethane species ÷ (amount of unreacted dibromomethane species + amount of reacted dibromomethane species);

CO₂selectivity of (a) the amount of substance of the reactant converted to carbon dioxide ÷ (amount of substance of the reactant converted to non-carbon dioxide + amount of substance of the reactant converted to carbon dioxide);

pseudo-boehmite is a commercially available product of Susan agent industries, Ltd., and the content of alumina is 72% by weight.

The firing described in the following examples and comparative examples is carried out in an air atmosphere without particular limitation.

Example 1

(1) Mixing 50g of alumina, 25g of urea, 5g of concentrated nitric acid (mass fraction: 68%, the same applies hereinafter) and 100g of water, stirring for 30 minutes at the rotating speed of 500rpm, and then colloid-milling for 30 minutes by using a colloid mill (the width of a tooth gap of the colloid mill is 0.05mm) to obtain alumina slurry;

in a coater, a slurry containing alumina was coated on a cordierite monolith carrier (having a parallel channel structure with openings at both ends, a porosity of 60%, and a cross-sectional area of each channel of 1 mm) under a condition of 3kPa²) And blowing residual liquid in the cordierite monolithic carrier by adopting high-pressure nitrogen after the coating is finished, standing at room temperature for 10 hours, raising the temperature from 20 ℃ to 110 ℃ at the heating rate of 0.5 ℃/min, keeping for 10 hours for drying, and then raising the temperature from 110 ℃ to 550 ℃ at the heating rate of 0.5 ℃/min, keeping for 6 hours for roasting to obtain the cordierite monolithic carrier containing the alumina coating. Through multiple times of dipping, drying and roasting, the alumina coating accounts for 10 percent of the total mass of the alumina coating and the cordierite monolithic carrier.

(2) Preparing cobalt nitrate hexahydrate and manganese nitrate into an aqueous solution according to a molar ratio shown in table 1, adding a sodium carbonate solution and the aqueous solution into a reaction container in a cocurrent manner under the condition of stirring at 60 ℃ (300rpm), controlling the pH value of a reaction system to be 9.5, filtering, drying the obtained precipitate at 110 ℃ for 5 hours, and roasting at 500 ℃ for 6 hours to obtain composite oxide particles;

dispersing the obtained composite oxide particles into water, then using a colloid mill (the tooth peak size of the colloid mill is 0.05mm) for 30min to obtain slurry containing the composite oxide, wherein the solid content of the slurry is 25 wt%, coating the slurry containing the composite oxide on a cordierite monolithic carrier containing an alumina coating in a coating machine under the condition of 3kPa, blowing the residual slurry in a pore channel by using high-pressure nitrogen after the coating is finished, then drying for 5h at 110 ℃, roasting for 6h at 550 ℃, and obtaining a semi-finished catalyst through multiple times of impregnation, drying and roasting, wherein the loading capacity of the composite oxide is 90g/L in terms of oxide relative to 1L of the monolithic carrier containing the alumina coating.

Preparing chloroplatinic acid and palladium chloride into an aqueous solution containing platinum elements and palladium elements (the total content of the platinum elements and the palladium elements is 0.1 percent by weight in terms of metal elements), soaking the semi-finished catalyst in the aqueous solution containing the platinum elements and the palladium elements in an equivalent manner, drying the impregnated semi-finished catalyst at 110 ℃ for 5 hours, and roasting the impregnated semi-finished catalyst at 550 ℃ for 6 hours to obtain the catalyst, wherein the supported amount of platinum and palladium is 400mg/L and the molar ratio of the platinum elements to the palladium elements is 0.25 in terms of metal elements relative to 1L of an alumina coating-containing monolithic carrier: 1.

(3) reducing the catalyst obtained in the step (2), specifically: the catalyst was subjected to reduction treatment at 300 ℃ for 6 hours in a mixed atmosphere of hydrogen and nitrogen (containing 5% by volume of hydrogen). Then in the mixed atmosphere of oxygen and nitrogen (oxygen content is 10 vol%), under the pressure of 0.1MPa and the volume space velocity of 20000h^-1Under the conditions of (1), contacting PTA simulated oxidation tail gas (the balance gas is nitrogen) containing 1000ppm of methyl acetate, 500ppm of p-xylene and 100ppm of dibromomethane with the catalyst after reduction treatment to carry out catalytic combustion reaction, gradually increasing the reaction temperature at the speed of 0.1 ℃/min from 200 ℃, recording the lowest reaction temperature T1 when the conversion rate of methyl acetate is 99%, the lowest reaction temperature T2 when the conversion rate of p-xylene is 99% and the lowest reaction temperature T3 when the conversion rate of dibromomethane is 99%, and calculating the CO at the 20 th hour after the reaction is carried out₂Selectivity of (2). The contents of the components of the obtained catalyst are shown in table 1; t1, T2 and T3 and CO₂The selectivities are shown in Table 2.

(4) Under the conditions of T3 temperature and other constant catalytic combustion conditions, the catalytic combustion reaction is carried out, and the conversion rate of methyl acetate, p-xylene and dibromomethane and the CO are reached to the 1000h₂The selectivities are shown in Table 2.

Example 2

A catalyst was prepared and an exhaust gas containing a bromine-containing organic matter was catalyzed for a catalytic combustion reaction according to the method of example 1, except that 50g of alumina was replaced with 50g of pseudo-boehmite, and cobalt nitrate hexahydrate and manganese nitrate were prepared as an aqueous solution in a molar ratio shown in Table 1. The raman spectrum of the composite oxide in the obtained catalyst is shown in fig. 1, and the peak position and the relative intensity of the peak are shown in table 3.

The contents of the components of the obtained catalyst are shown in table 1; t1, T2 and T3 and CO₂The selectivities are shown in Table 2.

The conversion rate of methyl acetate, p-xylene and dibromomethane and CO are calculated by the running time of 1000h₂The selectivities are shown in Table 2.

Example 3

A catalyst was prepared and an exhaust gas containing a bromine-containing organic compound was catalyzed for a combustion reaction by the method of example 1, except that cobalt nitrate hexahydrate and manganese nitrate were prepared as an aqueous solution in a molar ratio shown in table 1.

Example 4

A catalyst was prepared and an exhaust gas containing a bromine-containing organic compound was catalyzed for a catalytic combustion reaction according to the method of example 1, except that manganese nitrate was replaced with tetraethyl titanate in the step (2), cobalt nitrate hexahydrate and tetraethyl titanate were prepared as an aqueous ethanol solution in a molar ratio shown in table 1, and a sodium carbonate solution and the aqueous solution were fed into a reaction vessel in parallel with stirring at 20 ℃.

Example 5

A catalyst was prepared and an exhaust gas containing a bromine-containing organic substance was catalyzed for a catalytic combustion reaction according to the method of example 4, except that 50g of alumina was replaced with 50g of pseudo-boehmite, and cobalt nitrate hexahydrate and tetraethyl titanate were prepared as an ethanol aqueous solution in step (2) in the molar ratio shown in Table 1. The raman spectrum of the obtained composite oxide is shown in fig. 2, and the peak position and the relative intensity of the peak are shown in table 3.

Example 6

A catalyst was prepared and an exhaust gas containing bromine-containing organic matter was catalyzed for a catalytic combustion reaction according to the method of example 4, except that 50g of alumina was replaced with 50g of pseudo-boehmite, and cobalt nitrate hexahydrate and tetraethyl titanate were prepared as an aqueous ethanol solution in the molar ratio shown in Table 1.

Example 7

A catalyst was prepared and an exhaust gas containing a bromine-containing organic matter was catalyzed to perform a catalytic combustion reaction according to the method of example 4, except that 50g of alumina was replaced with 50g of pseudo-boehmite, cobalt nitrate hexahydrate and tetraethyl titanate were replaced with cobalt nitrate hexahydrate, manganese nitrate and tetraethyl titanate, and the cobalt nitrate hexahydrate, manganese nitrate and tetraethyl titanate were prepared into an aqueous ethanol solution in the molar ratio shown in table 1 (the volume ratio of ethanol to water was 1: 5). The raman spectrum of the obtained composite oxide is shown in fig. 3, and the peak position and the relative intensity of the peak are shown in table 3.

Example 8

A catalyst was prepared and an exhaust gas containing a bromine-containing organic compound was catalyzed to perform a catalytic combustion reaction according to the method of example 7, except that cobalt nitrate hexahydrate, manganese nitrate and tetraethyl titanate were prepared into an aqueous ethanol solution according to a molar ratio shown in table 1, a sodium carbonate solution and the aqueous ethanol solution were co-currently fed into a reaction vessel under stirring at 20 ℃, and the pH of the reaction system was controlled to 8.5.

Example 9

A catalyst was prepared and an exhaust gas containing a bromine-containing organic compound was catalyzed to perform a catalytic combustion reaction according to the method of example 7, except that cobalt nitrate hexahydrate, manganese nitrate and tetraethyl titanate were prepared into an aqueous ethanol solution according to a molar ratio shown in table 1, a sodium carbonate solution and the aqueous ethanol solution were added into a reaction vessel in parallel with stirring at 20 ℃, and the pH of the reaction system was controlled to 9.

Example 10

A catalyst was prepared and an exhaust gas containing a bromine-containing organic compound was catalyzed to perform a catalytic combustion reaction according to the method of example 7, except that cobalt nitrate hexahydrate, manganese nitrate and tetraethyl titanate were prepared into an aqueous ethanol solution according to a molar ratio shown in table 1, a sodium carbonate solution and the aqueous ethanol solution were added into a reaction vessel in parallel with stirring at 20 ℃, and the pH of the reaction system was controlled to 10.

The conversion rate of methyl acetate, p-xylene and dibromomethane is up to 1000hAnd CO₂The selectivities are shown in Table 2.

Example 11

A catalyst was prepared and an exhaust gas containing bromine-containing organic matter was catalyzed for a catalytic combustion reaction according to the method of example 7, except that 50g of pseudo-boehmite was replaced with 50g of alumina; the supported amount of the composite oxide was 35g/L in terms of oxide relative to 1L of the monolith support having an alumina coating layer.

Example 12

A catalyst was prepared and an exhaust gas containing bromine-containing organic matter was catalyzed for a catalytic combustion reaction according to the method of example 7, except that 50g of pseudo-boehmite was replaced with 50g of alumina; the supported amount of the composite oxide was 140g/L in terms of oxide relative to 1L of the monolith support having an alumina coating.

Example 13

A catalyst was prepared and an exhaust gas containing bromine-containing organic matter was catalyzed for a catalytic combustion reaction according to the method of example 7, except that 50g of pseudo-boehmite was replaced with 50g of alumina; in the step (2), the molar ratio of the platinum element to the palladium element in the obtained catalyst is 0.1: 1.

Example 14

A catalyst was prepared and a catalytic combustion reaction was carried out on an exhaust gas containing a bromine-containing organic matter by the method of example 13, except that, in the step (2), the molar ratio of platinum element and palladium element in the obtained catalyst was 0.5: 1.

Example 15

A catalyst was prepared and an exhaust gas containing bromine-containing organic matter was catalyzed for a catalytic combustion reaction according to the method of example 7, except that 50g of pseudo-boehmite was replaced with 50g of alumina; in the step (2), the loading amounts of platinum and palladium in terms of metal elements were 800mg/L relative to 1L of the monolithic carrier containing the alumina coating.

Example 16

A catalyst was prepared and an exhaust gas containing bromine-containing organic matter was catalyzed for a catalytic combustion reaction according to the method of example 7, except that 50g of pseudo-boehmite was replaced with 50g of alumina; contacting PTA simulated oxidation tail gas (the balance gas is nitrogen) containing 2000ppm of methyl acetate, 700ppm of p-xylene and 200ppm of dibromomethane with the catalyst after reduction treatment to perform catalytic combustion reaction.

Example 17

A catalyst was prepared and a catalytic combustion reaction was carried out by catalyzing exhaust gas containing bromine-containing organic matter according to the method of example 7, except that in the step (3), PTA simulated oxidation tail gas (balance nitrogen gas) containing 3000ppm of methyl acetate, 1000ppm of p-xylene and 300ppm of dibromomethane was contacted with the catalyst after the reduction treatment to carry out the catalytic combustion reaction.

Example 18

A catalyst was prepared and a catalytic combustion reaction was conducted by catalyzing exhaust gas containing bromine-containing organic matter in accordance with the method of example 7, except that the alumina coating layer was 15% by mass of the total mass of the alumina coating layer and the cordierite monolithic carrier.

Example 19

A catalyst was prepared and a catalytic combustion reaction was conducted by catalyzing exhaust gas containing bromine-containing organic matter in accordance with the method of example 7, except that the alumina coating layer was 7% by mass of the total mass of the alumina coating layer and the cordierite monolithic carrier.

Example 20

A catalyst was prepared and a catalytic combustion reaction was conducted in the same manner as in example 7 except that the supported amount of the composite oxide was 60g in terms of oxide with respect to 1L of the monolith carrier.

Example 21

A catalyst was prepared and a catalytic combustion reaction was conducted in the same manner as in example 7 except that the supported amount of the composite oxide was 120g in terms of oxide with respect to 1L of the monolith carrier.

Example 22

A catalyst was prepared and a catalytic combustion reaction was carried out by catalyzing an exhaust gas containing a bromine-containing organic substance according to the method of example 7, except that, in the step (2), the molar ratio of the platinum element to the palladium element in the obtained catalyst was 10: 1.

Example 23

A catalyst was prepared and an exhaust gas containing a bromine-containing organic compound was catalyzed for a catalytic combustion reaction according to the method of example 7, except that cobalt nitrate hexahydrate, manganese nitrate and tetraethyl titanate were prepared into an aqueous ethanol solution in the molar ratios shown in table 1.

Example 24

Comparative example 1

A catalyst was prepared and a catalytic combustion reaction was carried out by catalyzing exhaust gas containing a bromine-containing organic substance in accordance with the method of example 7, except that in the step (2), the alumina-coated cordierite monolithic carrier obtained in the step (1) was impregnated directly with an aqueous solution containing a platinum element and a palladium element without carrying out the supporting of the composite oxide.

Comparative example 2

A catalyst was prepared and an exhaust gas containing bromine-containing organic matter was catalyzed for a catalytic combustion reaction according to the method of example 7, except that cobalt nitrate hexahydrate, manganese nitrate and tetraethyl titanate were replaced with cobalt nitrate hexahydrate, and cobalt nitrate hexahydrate was prepared as an aqueous solution.

Comparative example 3

A catalyst was prepared and an exhaust gas containing a bromine-containing organic matter was catalyzed for a catalytic combustion reaction according to the method of example 7, except that cobalt nitrate hexahydrate, manganese nitrate and tetraethyl titanate were replaced with manganese nitrate, and manganese nitrate was prepared as an aqueous solution.

Comparative example 4

A catalyst was prepared and an exhaust gas containing bromine-containing organic matter was catalyzed by a catalytic combustion reaction according to the method of example 7, except that cobalt nitrate hexahydrate, manganese nitrate and tetraethyl titanate were replaced with tetraethyl titanate, and the tetraethyl titanate was prepared as an aqueous ethanol solution.

Comparative example 5

A catalyst was prepared and an exhaust gas containing a bromine-containing organic matter was catalyzed for a catalytic combustion reaction according to the method of example 7, except that cobalt nitrate hexahydrate, manganese nitrate and tetraethyl titanate were replaced with cobalt nitrate hexahydrate and manganese nitrate, and an aqueous solution was prepared in accordance with the molar ratio shown in table 1. The raman spectrum of the obtained composite oxide is shown in fig. 4, and the peak position and the relative intensity of the peak are shown in table 4.

Comparative example 6

A catalyst was prepared and an exhaust gas containing a bromine-containing organic matter was catalyzed for a catalytic combustion reaction according to the method of example 7, except that cobalt nitrate hexahydrate, manganese nitrate and tetraethyl titanate were replaced with cobalt nitrate hexahydrate and manganese nitrate, and an aqueous solution was prepared in accordance with the molar ratio shown in table 1. The raman spectrum of the obtained composite oxide is shown in fig. 5, and the peak position and the relative intensity of the peak are shown in table 4.

Comparative example 7

A catalyst was prepared and an exhaust gas containing a bromine-containing organic matter was catalyzed for a catalytic combustion reaction according to the method of example 7, except that cobalt nitrate hexahydrate, manganese nitrate and tetraethyl titanate were replaced with cobalt nitrate hexahydrate and tetraethyl titanate, and an ethanol aqueous solution was prepared in the molar ratio shown in table 1.

TABLE 1

TABLE 2

TABLE 3

Raman shift (cm)^-1)	175-230	450-475	475-525	615-725
					Relative strength	M	W	W	VS

Note: w, M, S and VS represent peak intensities in the Raman spectrum, W is less than 20 for weak, M is 20-40 for medium, S is 40-70 for strong, and VS is greater than 70 for very strong, the same applies below.

TABLE 4

Raman shift (cm)^-1)	150-175	450-475	475-525	550-650
					Relative strength	M	W	W	VS

As can be seen from tables 1 and 2, the catalyst prepared by the embodiment of the technical scheme of the invention can catalyze the mixed gas of methyl acetate, p-xylene and dibromomethane to carry out catalytic combustion reaction at a lower reaction temperature, the conversion rates of the methyl acetate, the p-xylene and the dibromomethane can still reach more than 99%, and the CO reaction lasts for 20h₂The selectivity of the catalyst can reach 99 percent, which shows that the catalyst has higher catalytic activity and selectivity, and still has higher catalytic activity and selectivity when the catalytic combustion reaction is carried out for 1000h at the temperature of T3, which shows that the catalyst has better stability and higher halogen toxicity resistance.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims

1. A catalyst for purifying an exhaust gas containing a bromine-containing organic substance, characterized by comprising a monolith carrier containing an alumina coating layer and a noble metal active component and a non-noble metal active component supported on the monolith carrier;

2. the catalyst according to claim 1, wherein the molar ratio of Co to Mn in the composite oxide is 3.5 to 14.5: 1, preferably 6 to 12: 1;

preferably, the molar ratio of Co to Ti in the composite oxide is 1.5 to 7.5: 1, preferably 3 to 6: 1;

preferably, the loading amount of the non-noble metal active component is 30-150g, more preferably 35-140g, and further preferably 60-120g in terms of oxide relative to 1L of the monolithic carrier;

preferably, the non-noble metal active component is a composite oxide containing cobalt oxide, manganese oxide and titanium oxide.

3. The catalyst as claimed in claim 1, wherein the Raman spectrum of the composite oxide in the catalyst is 615-725cm^-1The peak intensity at the position is higher than 175-230cm^-1Peak intensity at position 175-^-1The peak intensity at the position is higher than 450-^-1Peak intensity at position and 475-^-1Peak intensity at location.

4. The catalyst according to claim 1 or 2, wherein the loading amount of the noble metal active component is 100-2000mg, more preferably 400-800mg, in terms of metal element relative to 1L of the monolithic support;

preferably, the noble metal is selected from at least one of Au, Ag, Pt, Pd, Ru, Rh, Os, and Ir;

preferably, the noble metal is Pt and/or Pd;

preferably, the noble metals are Pt and Pd;

further preferably, the molar ratio of Pt and Pd in the noble metal active component is 0.01 to 10: 1, more preferably 0.05 to 5: 1, more preferably 0.1 to 0.5: 1.

5. a catalyst according to any one of claims 1 to 4, wherein the alumina coating is present in the monolithic support in an amount of from 5 to 20 wt%, preferably from 7 to 15 wt%;

preferably, the porosity of the cross section of the monolithic support is 30 to 90%;

preferably, the monolithic carrier is a ceramic monolithic carrier;

preferably, the ceramic monolith support is selected from at least one of a cordierite monolith support, a mullite monolith support, a zirconia monolith support and an alumina monolith support.

6. A method for preparing a catalyst for purifying an exhaust gas containing a bromine-containing organic substance, the method comprising:

7. the production method according to claim 6, wherein the slurry containing alumina and/or an alumina precursor and the monolith support are used in such amounts that the alumina coating layer content of the alumina coating layer-containing monolith support obtained in step (1) is 5 to 20% by weight, more preferably 7 to 15% by weight;

preferably, the slurry containing alumina and/or alumina precursors contains alumina and/or alumina precursors, water and optionally pore formers, optionally acids;

preferably, the weight ratio of alumina and/or alumina precursor to water, calculated as alumina, is between 0.05 and 0.8: 1, more preferably 0.3 to 0.7: 1;

preferably, the weight ratio of the alumina and/or the alumina precursor to the pore former, calculated as alumina, is 1: 0.3-2.5, more preferably 1: 0.35-1.5;

preferably, the weight ratio of alumina and/or alumina precursor to acid, calculated as alumina, is 1: 0.01 to 0.2, more preferably 1: 0.05-0.15;

preferably, the alumina precursor is pseudo-boehmite and/or alumina sol;

preferably, the pore-forming agent is selected from at least one of urea, carboxymethyl cellulose and polyvinyl alcohol;

preferably, the acid is selected from HNO₃、H₂SO₄、HCl、CH₃COOH and H₂C₂O₄At least one of;

preferably, the drying conditions of step (1) include: the drying temperature is 80-130 ℃, preferably 100-125 ℃; the drying time is 1-25h, preferably 2-10 h;

preferably, the roasting conditions in step (1) include: roasting in an oxygen-containing atmosphere, wherein the roasting temperature is 300-600 ℃, and preferably 450-550 ℃; the roasting time is 3-10h, preferably 5-8 h.

8. The production method according to claim 6 or 7, wherein the step (2) comprises the steps of:

(2-2) loading a noble metal active component on the semi-finished product catalyst;

preferably, the step (2-1) supports the composite oxide containing cobalt oxide, manganese oxide and titanium oxide on the monolithic carrier containing an alumina coating layer.

9. The production method according to claim 8, wherein the step (2-1) includes: coating the slurry containing the composite oxide on an integral carrier containing an alumina coating, and then drying and/or roasting to obtain a semi-finished catalyst; and/or the presence of a gas in the gas,

the step (2-2) comprises: coating the slurry containing the noble metal source on the semi-finished catalyst, and then roasting;

preferably, the solid content of the slurry containing the composite oxide is 10 to 35% by weight, preferably 20 to 30% by weight;

preferably, the slurry containing the composite oxide and the monolithic carrier containing the alumina coating are used in such amounts that the prepared semi-finished catalyst has a composite oxide loading amount of 30 to 150g, more preferably 35 to 140g, further preferably 60 to 120g, in terms of oxide, relative to 1L of the monolithic carrier containing the alumina coating;

preferably, the drying conditions of step (2-1) include: the drying temperature is 80-130 ℃, and more preferably 100-125 ℃; the drying time is 1-25h, more preferably 2-10 h;

preferably, the roasting conditions in step (2-1) include: in an oxygen-containing atmosphere, the roasting temperature is 300-600 ℃, and more preferably 450-550 ℃; the calcination time is 3 to 10 hours, more preferably 3.5 to 7 hours.

10. The production method according to any one of claims 6 to 9, wherein the molar ratio of Co to Mn in the composite oxide is 3.5 to 14.5: 1, preferably 6 to 12: 1;

preferably, the composite oxide in the step (2) is prepared by a coprecipitation method;

preferably, the preparation method of the composite oxide in the step (2) comprises: mixing a precursor solution containing cobalt and a precursor of manganese and/or a precursor of titanium with a precipitator for precipitation reaction to obtain a precipitation product, and then drying and roasting the precipitation product;

preferably, the precursor solution contains a precursor of cobalt, a precursor of manganese and a precursor of titanium;

preferably, the precursor of cobalt and the precursor of manganese are each independently selected from at least one of nitrate, acetate, sulfate, oxalate and halide of metal;

preferably, the precursor of titanium is a titanate and/or titanium tetrachloride;

preferably, the precipitant is selected from at least one of carbonates, bicarbonates, and hydroxides of alkali metals, more preferably from at least one of sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, and lithium hydroxide;

preferably, the conditions of the precipitation reaction include: the reaction temperature is 10-90 ℃, and more preferably 50-80 ℃; the pH value is 8.5-11, and more preferably 9-10;

preferably, the conditions for drying the precipitated product include: the drying temperature is 100-120 ℃, and the drying time is 2-8 h;

preferably, the conditions for calcining the precipitated product include: in an oxygen-containing atmosphere, the roasting temperature is 400-600 ℃, and more preferably 450-550 ℃; the calcination time is 3 to 8 hours, more preferably 3.5 to 7 hours.

11. The production method as claimed in claim 9, wherein the slurry containing a noble metal source and the semi-finished catalyst are used in amounts such that the loading amount of the noble metal in the produced catalyst is 100-2000mg, more preferably 400-800mg, in terms of the metal element relative to 1L of the monolithic support containing an alumina coating;

preferably, the noble metal source is selected from at least one precursor of Au, Ag, Pt, Pd, Ru, Rh, Os and Ir, more preferably a precursor of Pt and/or a precursor of Pd, and further preferably a precursor of Pt and a precursor of Pd;

preferably, the precursor of Pt and the precursor of Pd are used in such amounts that the molar ratio of Pt to Pd supported on the surface of the alumina-coated monolithic carrier is 0.01-10: 1, more preferably 0.05 to 5: 1, more preferably 0.1 to 0.5: 1;

preferably, the precursor of Pt and the precursor of Pd are each independently a soluble acid and/or a soluble salt of a metal;

preferably, the precursor of Pt is selected from at least one of chloroplatinic acid, platinum nitrate and platinum chloride;

preferably, the precursor of Pd is selected from at least one of palladium nitrate, tetraaminopalladium nitrate and palladium chloride;

preferably, the roasting conditions in step (2-2) include: in an oxygen-containing atmosphere, the roasting temperature is 300-600 ℃, and more preferably 450-550 ℃; the calcination time is 3-10h, more preferably 5-8 h.

12. A catalyst for purifying an exhaust gas containing a bromine-containing organic compound, which is produced by the production method according to any one of claims 6 to 11.

13. A method for purifying an exhaust gas containing a bromine-containing organic substance, characterized in that the exhaust gas containing a bromine-containing organic substance is subjected to catalytic combustion in an oxygen-containing atmosphere by contacting it with the catalyst according to any one of claims 1 to 5 and claim 12.

14. The method of claim 13, wherein the conditions of catalytic combustion comprise: the temperature is 200-450 ℃, and the optimal temperature is 250-400 ℃; the volume space velocity is 3000-30000h^-1Preferably 5000-^-1(ii) a The pressure is 0 to 3MPa, preferably 0 to 2 MPa.

15. The method according to claim 13 or 14, wherein the content of the bromine-containing organic matter in the exhaust gas containing the bromine-containing organic matter is 0 to 100ppm as Br element;

preferably, the bromine-containing organic substance is selected from at least one of dibromomethane, monobromomethane, monobromoethane and dibromoethane.