CN111054355A

CN111054355A - Integral non-noble metal catalyst for catalytic combustion treatment of PTA tail gas

Info

Publication number: CN111054355A
Application number: CN201811201518.6A
Authority: CN
Inventors: 卢媛娇; 缪长喜; 蒋见
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: 2018-10-16
Filing date: 2018-10-16
Publication date: 2020-04-24
Anticipated expiration: 2038-10-16
Also published as: CN111054355B

Abstract

The invention mainly relates to an integral non-noble metal catalyst for treating PTA tail gas by catalytic combustion, which is a honeycomb ceramic monolithic catalyst of loaded vacancy type perovskite and takes a composite oxide (C-Al-O) of rare earth and aluminum as a carrier coating. The perovskite catalyst and the carrier of C-Al-O are synthesized by adopting a coprecipitation method, then the carrier of C-Al-O is coated on the honeycomb ceramic, and then the perovskite powder is coated on the honeycomb ceramic loaded with the carrier to obtain the monolithic catalyst. The catalyst prepared by the invention has the characteristics of low cost, high activity and good toxicity resistance, and can realize high-efficiency catalytic combustion removal on PTA and other industrial waste gases.

Description

Integral non-noble metal catalyst for catalytic combustion treatment of PTA tail gas

Technical Field

The invention relates to an integral non-noble metal catalyst for treating PTA tail gas by catalytic combustion and a preparation method thereof, belonging to the technical field of catalytic combustion environmental protection.

Background

Purified Terephthalic Acid (PTA) oxidation tail gas is organic waste gas containing various pollutants and discharged by an oxidation reactor, and is the harmful gas with the largest discharge amount of a PTA device. The main component N of the gas₂The volume fraction of the organic matter is about 94 percent, and the total mass concentration of the organic matter is more than 1000mg/m³Mass concentration of bromide about 100mg/m³The mass concentration of CO is about 5000mg/m³All of them are seriously over the national emission standard.

Although various measures are taken by various PTA manufacturers in China in the past to treat the oxidized tail gas, the treatment effect is not ideal. With the continuous enhancement of the environmental protection consciousness of human beings and the continuous perfection of environmental protection laws and regulations, the requirement for thoroughly treating the oxidized tail gas is more and more strong. Driven by this demand, class 2 technologies have emerged in recent years, and have been used industrially as PTA oxidation tail gas treatment technologies, one of which is called Thermal oxidation (Thermal oxidation) technology, and the other is called Catalytic oxidation (Catalytic oxidation) technology, or Catalytic Combustion (Catalytic Combustion) technology. The thermal oxidation technology is characterized in that harmful substances in the tail gas are cracked at high temperature, and the temperature of the thermal cracking is as high as 800-900 ℃. The catalytic oxidation technology reduces the operation temperature to 280-450 ℃ by means of the action of the catalyst.

The thermal oxidation technology can remove pollutants such as methyl acetate, p-xylene, carbon monoxide and the like in PTA tail gas, but the removal rate of bromide in the PTA tail gas is low and is only 57%, the incineration temperature is as high as 800 ℃, a large amount of fuel oil needs to be consumed, the operation cost is high, potential safety hazards exist due to improper operation, and NO can be generated simultaneously_x. The catalytic combustion is carried out at a low temperature (250-400 ℃), and the organic matters are subjected to flameless combustion oxidation by using the catalyst and are converted into carbon dioxide and water. The operation is safe and stable, no large valve bank is frequently switched, the operation cost is low, and no secondary pollution is generated. Therefore, catalytic combustion is the most popular technology for controlling PTA exhaust emissions among manufacturers.

The catalyst for catalytic combustion mainly comprises noble metal catalysts such as Pt, Pd, Rh and the like, which have high activity and good selectivity, but have rare resources and high price, the current industrial catalytic combustion catalyst is mainly the noble metal catalyst, and the industrial catalytic combustion catalyst in China is imported, and the main suppliers are Engelhard, Johnson Matthey and other companies; 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 easy to obtain, has higher catalytic activity than a corresponding single oxide, can reach the activity of a noble metal catalyst under certain conditions, and is a hotspot of research in the field of catalytic combustion catalysts at present, for example, patent CN103252242B discloses a catalytic combustion catalyst of a composite oxide of copper, manganese and cerium. Compared with noble metal catalysts, the composite metal oxide catalyst has the advantages of low price, halogen poisoning resistance and reliable stability, so the development of the non-noble metal composite oxide catalytic combustion catalyst has wide application prospect.

Disclosure of Invention

The invention aims to solve the problems of high price, poor toxicity resistance and the like of a PTA tail gas catalytic combustion noble metal catalyst in the prior art, and provides a novel integral non-noble metal catalyst for catalytic combustion treatment of PTA tail gas and a preparation method thereof.

The technical scheme adopted by the invention is as follows: the monolithic non-noble metal catalyst for treating PTA tail gas by catalytic combustion comprises an active component, a carrier coating and a honeycomb ceramic skeleton, wherein the active component is a vacancy type perovskite catalyst A_xBO₃Wherein x is 0.6-0.95, A is at least one of La, Ce and Bi, B is transition metal Co, and the carrier coating is a composite oxide of C-Al-O, wherein C is at least one of Ce, Pr and Sm.

In the technical scheme, the perovskite catalyst A with the defect type active component_xBO₃Wherein x is 0.75 to 0.86.

In the technical scheme, the perovskite catalyst A with the defect type active component_xBO₃Wherein x is 0.78-0.82.

In the technical scheme, the molar ratio of the C element to the Al element is 1:10-1: 20.

In the technical scheme, A is at least two of La, Ce and Bi; the preferable scheme is that A is La and Bi or Ce and Bi; in the technical scheme, the molar ratio of the two elements at the A position is 9: 1-1: 9.

The most preferable technical scheme is that A is a mixture of La, Ce and Bi, wherein the molar ratio of lanthanide to Bi is 8:2, and the molar ratio of lanthanide La to Ce is 3: 1-1: 3.

In the technical scheme, the carrier coating is a composite oxide of C-Al-O, and C is selected from Ce and Pr, or from Sm and Pr, or from Ce and Sm.

The invention relates to a preparation method of an integral catalyst for purifying PTA oxidized tail gas, which comprises the following steps: 1) preparing vacancy type perovskite catalyst powder; 2) preparing carrier composite oxide coating powder; 3) pretreating the honeycomb ceramic; 4) coating of a carrier coating; 5) coating of the active ingredient.

The preparation method comprises the following steps of: precipitating a salt solution of a metal A, B component and an alkaline precipitator to a pH value of 10-11, filtering and washing until the pH value is 7-8, drying at 100-120 ℃ for 10-12 h, and roasting at 600-800 ℃ for 3-5 h to obtain the perovskite powder catalyst.

The above preparation method, wherein the preparation of the washcoat: precipitating a metal salt solution of a C element and an Al element and an alkaline precipitator to a pH value of 9-11, filtering and washing until the pH value is 7-8, drying at 100-120 ℃ for 10-12 h, and roasting at 400-600 ℃ for 2-5 h to obtain C-Al-O composite oxide catalyst powder.

The preparation method comprises the following steps: drying the honeycomb ceramic at 100-120 ℃ for 4-8 h, and roasting at 300-500 ℃ for 2-5 h.

The above preparation method, wherein the application of the washcoat: firstly dispersing carrier composite oxide coating powder into water to prepare a coating liquid I, dipping the honeycomb ceramic in the coating liquid I for 3-8 hours, taking out slurry remained in a blow-drying duct, drying at 100-120 ℃ for 10-12 hours, roasting at 400-600 ℃ for 2-5 hours, weighing, repeating the coating process for at least 3 times until the coating amount on a honeycomb ceramic framework in unit volume is 180-240 g/L, and the mass ratio of solids in the coating liquid I is 30-50%.

The above preparation method, wherein the coating of the active ingredient: firstly dispersing vacancy type perovskite catalyst powder into water to prepare a coating liquid II, dipping the honeycomb ceramic loaded with the carrier in the step 4) into the coating liquid II for 3-8 hours, then taking out, blow-drying residual slurry in a pore channel, drying at 100-120 ℃ for 10-12 hours, roasting at 400-600 ℃ for 2-5 hours, then dry-weighing, repeating the coating process for at least 3 times until the coating amount on a honeycomb ceramic framework in unit volume is 50-100 g/L, and preparing the integral non-noble metal catalyst, wherein the solid mass ratio of the coating liquid II is 30-50%.

The invention relates to a method for catalytic combustion of PTA oxidized tail gas, which comprises the following steps: the required amount of catalyst is put into a constant temperature area of a fixed bed reactor, and the upper part and the lower part of the catalyst are filled with porcelain rings. The main components of the oxidation tail gas of the PTA device are methyl acetate, paraxylene and methyl bromide. Under the set temperature and pressure, the tail gas is sent to a preheater by a flowmeter, mixed and gasified with oxygen and nitrogen, then enters the upper end of a reactor, flows through a catalyst bed layer for catalytic reaction, the reaction product is directly injected by a valve and enters a gas chromatograph, and the conversion rate of the tail gas and the selectivity of the product are analyzed on line. The treated tail gas containing 500-25000ppm of catalyst per gram is 5-50L per hour. The reaction activity of the catalyst takes the high and low reaction temperature of the oxidation tail gas component for complete conversion as an evaluation standard, and the lower the complete conversion temperature is, the better the performance of the catalyst is. Wherein T is₉₉The reaction temperature at which the purification rate of the component in the off-gas was 99% was shown. T of Mixed sample₉₉Expressed as the reaction temperature at which the purification of all components reached 99%. T of Mixed sample_nThe purification rate of dibromomethane at 400 ℃ is represented as n%, and the purification rates of methyl acetate and p-xylene at this time are 99% or more.

Compared with the prior art, the invention adopts non-noble metal with lower price as the active component, achieves better elimination effect, and has high activity and stability. The catalyst prepared by the method is used for PTA tail gas treatment reaction, the purification rate of the oxidized tail gas is more than 99% at the reaction temperature of 200-400 ℃, and the reaction product is CO₂，H₂O, HBr and Br₂The selectivity of the final product carbon dioxide is more than 99 percent. Wherein HBr and Br₂Can be completely absorbed by the alkali solution, has good elimination effect, keeps the performance of the catalyst stable, and obtains better technical effect.

The invention is further illustrated by the following examples.

Detailed Description

[ example 1 ]

Preparation of the washcoat: a solution of 43.41g of cerium nitrate and 375.13g of aluminum nitrate was prepared, and 20 wt% aqueous ammonia was added thereto under stirring to a pH of 10.5, followed by filtration, drying at 110 ℃ and calcination at 450 ℃ for 4 hours to obtain cerium-aluminum oxide powder.

Preparation of active ingredients: lanthanum nitrate 22.21g and cobalt nitrate 29.10g are prepared into a solution, a mixed solution of sodium hydroxide and sodium carbonate is added to the solution under the condition of stirring until the pH value is 10.5, then the solution is filtered and washed, dried at 110 ℃, and roasted at 650 ℃ for 4 hours to obtain perovskite powder.

Coating of the carrier coating: firstly, dispersing cerium-aluminum composite oxide powder into water to prepare a coating solution I, dipping the honeycomb ceramic into the coating solution I for 4 hours, taking out the honeycomb ceramic to blow dry the residual slurry in a pore channel, drying the honeycomb ceramic at 110 ℃ for 12 hours, roasting the honeycomb ceramic at 500 ℃ for 3 hours, weighing the honeycomb ceramic, and repeating the coating process for 3 times.

Coating of active ingredients: firstly, dispersing perovskite powder into water to prepare a coating liquid II, dipping the honeycomb ceramic loaded with the carrier into the coating liquid II for 4 hours, then taking out the honeycomb ceramic, blow-drying the slurry remained in a pore channel, drying the honeycomb ceramic at 110 ℃ for 12 hours, roasting the honeycomb ceramic at 500 ℃ for 3 hours, then weighing the honeycomb ceramic in a drying way, and repeating the coating process for 3 times to obtain the monolithic non-noble metal catalyst, wherein the component content of the catalyst is shown in Table 1.

[ example 2 ]

Preparation of active ingredients: lanthanum nitrate 35.17g and cobalt nitrate 29.10g are prepared into a solution, a mixed solution of sodium hydroxide and sodium carbonate is added to the solution under the condition of stirring until the pH value is 10.5, then the solution is filtered and washed, dried at 110 ℃, and roasted at 650 ℃ for 4 hours to obtain perovskite powder.

[ example 3 ]

Preparation of active ingredients: a solution is prepared by 27.77g of lanthanum nitrate and 29.10g of cobalt nitrate, a mixed solution of sodium hydroxide and sodium carbonate is added to the solution under the condition of stirring until the pH value is 10.5, then the solution is filtered and washed, dried at 110 ℃, and roasted at 650 ℃ for 4 hours to obtain perovskite powder.

[ example 4 ]

Preparation of active ingredients: lanthanum nitrate 31.84g and cobalt nitrate 29.10g are prepared into a solution, a mixed solution of sodium hydroxide and sodium carbonate is added into the solution under the condition of stirring until the pH value is 10.5, then the solution is filtered and washed, dried at 110 ℃, and roasted at 650 ℃ for 4 hours to obtain perovskite powder.

[ example 5 ]

Preparation of active ingredients: 28.88g of lanthanum nitrate and 29.10g of cobalt nitrate are prepared into a solution, a mixed solution of sodium hydroxide and sodium carbonate is added into the solution under the condition of stirring until the pH value is 10.5, then the solution is filtered, washed, dried at 110 ℃, and roasted at 650 ℃ for 4 hours to obtain perovskite powder.

[ example 6 ]

Preparation of active ingredients: lanthanum nitrate 30.36g and cobalt nitrate 29.10g are prepared into a solution, a mixed solution of sodium hydroxide and sodium carbonate is added into the solution under the condition of stirring until the pH value is 10.5, then the solution is filtered and washed, dried at 110 ℃, and roasted at 650 ℃ for 4 hours to obtain perovskite powder.

[ example 7 ]

Preparation of the washcoat: a solution of 43.41g of cerium nitrate and 750.26g of aluminum nitrate was prepared, and 20 wt% aqueous ammonia was added thereto with stirring to adjust the pH to 10.5, followed by filtration, drying at 110 ℃ and calcination at 450 ℃ for 4 hours to obtain cerium-aluminum oxide powder.

[ example 8 ]

Preparation of active ingredients: 33.86g of cerium nitrate and 29.10g of cobalt nitrate are prepared into a solution, a mixed solution of sodium hydroxide and sodium carbonate is added to the solution under the condition of stirring until the pH value is 10.5, then the solution is filtered, washed, dried at 110 ℃ and roasted at 650 ℃ for 4 hours to obtain perovskite powder.

[ example 9 ]

Preparation of active ingredients: preparing a solution from 37.84g of bismuth nitrate and 29.10g of cobalt nitrate, adding a mixed solution of sodium hydroxide and sodium carbonate to the solution under the condition of stirring until the pH value is 10.5, filtering and washing, drying at 110 ℃, and roasting at 650 ℃ for 4 hours to obtain perovskite powder.

[ example 10 ]

Preparation of the washcoat: 33.90g of praseodymium nitrate and 750.26g of aluminum nitrate are prepared into a solution, 20 wt% of ammonia water is added into the solution under the condition of stirring until the pH value is 10.5, and then the solution is filtered, dried at 110 ℃ and roasted at 450 ℃ for 4 hours to obtain praseodymium-aluminum oxide powder.

Coating of the carrier coating: dispersing praseodymium-aluminum composite oxide powder into water to prepare a coating liquid I, soaking the honeycomb ceramic in the coating liquid I for 4 hours, taking out the honeycomb ceramic to blow dry the residual slurry in a pore channel, drying the honeycomb ceramic at 110 ℃ for 12 hours, roasting the honeycomb ceramic at 500 ℃ for 3 hours, weighing the honeycomb ceramic, and repeating the coating process for 3 times.

[ example 11 ]

Preparation of the washcoat: a solution is prepared by 44.45g of samarium nitrate and 750.26g of aluminum nitrate, 20 wt% of ammonia water is added to the solution under the condition of stirring until the pH value is 10.5, and then the solution is filtered, dried at 110 ℃ and roasted at 450 ℃ for 4 hours to obtain samarium aluminum oxide powder.

Coating of the carrier coating: firstly, dispersing samarium-aluminum composite oxide powder into water to prepare a coating solution I, dipping the honeycomb ceramic in the coating solution I for 4 hours, taking out the honeycomb ceramic to blow dry the residual slurry in a pore channel, drying the honeycomb ceramic at 110 ℃ for 12 hours, roasting the honeycomb ceramic at 500 ℃ for 3 hours, weighing the honeycomb ceramic, and repeating the coating process for 3 times.

[ example 12 ]

Preparation of active ingredients: lanthanum nitrate 25.99g, bismuth nitrate 3.78g and cobalt nitrate 29.10g are prepared into a solution, a mixed solution of sodium hydroxide and sodium carbonate is added into the solution under the condition of stirring until the pH value is 10.5, then the solution is filtered, washed, dried at 110 ℃ and roasted at 650 ℃ for 4 hours to obtain perovskite powder.

[ example 13 ]

Preparation of active ingredients: lanthanum nitrate 23.10g, bismuth nitrate 7.57g and cobalt nitrate 29.10g are prepared into a solution, a mixed solution of sodium hydroxide and sodium carbonate is added into the solution under the condition of stirring until the pH value is 10.5, then the solution is filtered, washed, dried at 110 ℃ and roasted at 650 ℃ for 4 hours to obtain perovskite powder.

[ example 14 ]

Preparation of active ingredients: lanthanum nitrate 2.89g, bismuth nitrate 34.05g and cobalt nitrate 29.10g are prepared into a solution, a mixed solution of sodium hydroxide and sodium carbonate is added to the solution under the condition of stirring until the pH value is 10.5, then the solution is filtered, washed, dried at 110 ℃ and roasted at 650 ℃ for 4 hours to obtain perovskite powder.

[ example 15 ]

Preparation of active ingredients: lanthanum nitrate 25.99g, cerium nitrate 3.39g and cobalt nitrate 29.10g are prepared into a solution, a mixed solution of sodium hydroxide and sodium carbonate is added into the solution under the condition of stirring until the pH value is 10.5, then the solution is filtered, washed, dried at 110 ℃ and roasted at 650 ℃ for 4 hours to obtain perovskite powder.

[ example 16 ]

Preparation of active ingredients: a solution is prepared by 27.09g of cerium nitrate, 7.57g of bismuth nitrate and 29.10g of cobalt nitrate, a mixed solution of sodium hydroxide and sodium carbonate is added to the solution under the condition of stirring until the pH value is 10.5, then the solution is filtered, washed, dried at 110 ℃ and roasted at 650 ℃ for 4 hours to obtain perovskite powder.

[ example 17 ]

Preparation of active ingredients: preparing a solution from 17.33g of lanthanum nitrate, 6.77g of cerium nitrate, 7.57g of bismuth nitrate and 29.10g of cobalt nitrate, adding a mixed solution of sodium hydroxide and sodium carbonate to the solution under the condition of stirring until the pH value is 10.5, filtering and washing, drying at 110 ℃, and roasting at 650 ℃ for 4 hours to obtain perovskite powder.

[ example 18 ]

Preparation of active ingredients: lanthanum nitrate 5.78g, cerium nitrate 20.32g, bismuth nitrate 7.57g and cobalt nitrate 29.10g are prepared into a solution, under the condition of stirring, a mixed solution of sodium hydroxide and sodium carbonate is added into the solution until the pH value is 10.5, then the solution is filtered and washed, dried at 110 ℃, and then roasted at 650 ℃ for 4 hours to obtain perovskite powder.

[ example 19 ]

[ example 20 ]

[ example 21 ]

[ example 22 ]

[ example 23 ]

Preparation of the washcoat: a cerium praseodymium aluminum oxide powder was obtained by preparing a solution from 21.71g of cerium nitrate, 16.95g of praseodymium nitrate and 750.26g of aluminum nitrate, adding 20 wt% of aqueous ammonia thereto under stirring to a pH of 10.5, filtering, drying at 110 ℃ and calcining at 450 ℃ for 4 hours.

Coating of the carrier coating: firstly, dispersing cerium praseodymium aluminum composite oxide powder into water to prepare a coating liquid I, dipping the honeycomb ceramic into the coating liquid I for 4 hours, taking out the residual slurry in a blow-drying pore channel, drying the honeycomb ceramic at 110 ℃ for 12 hours, roasting the honeycomb ceramic at 500 ℃ for 3 hours, weighing the honeycomb ceramic, and repeating the coating process for 3 times.

[ example 24 ]

Preparation of the washcoat: 16.95g of praseodymium nitrate, 22.22g of samarium nitrate and 750.26g of aluminum nitrate are prepared into a solution, 20 wt% of ammonia water is added into the solution under the condition of stirring until the pH value is 10.5, and then the solution is filtered, dried at 110 ℃ and roasted at 450 ℃ for 4 hours to obtain praseodymium-samarium aluminum oxide powder.

Coating of the carrier coating: the method comprises the steps of firstly dispersing praseodymium, samarium and aluminum composite oxide powder into water to prepare a coating liquid I, dipping the honeycomb ceramic into the coating liquid I for 4 hours, taking out the honeycomb ceramic to blow dry slurry remained in a pore channel, drying the honeycomb ceramic at 110 ℃ for 12 hours, roasting the honeycomb ceramic at 500 ℃ for 3 hours, weighing the honeycomb ceramic, and repeating the coating process for 3 times.

[ example 25 ]

Preparation of the washcoat: a solution is prepared by 21.71g of cerium nitrate, 22.22g of samarium nitrate and 750.26g of aluminum nitrate, 20 wt% of ammonia water is added to the solution under the condition of stirring until the pH value is 10.5, and then the solution is filtered, dried at 110 ℃ and roasted at 450 ℃ for 4 hours to obtain samarium aluminum oxide powder.

Coating of the carrier coating: firstly, dispersing cerium samarium aluminum composite oxide powder into water to prepare a coating solution I, dipping the honeycomb ceramic into the coating solution I for 4 hours, taking out the honeycomb ceramic to blow dry the residual slurry in a pore channel, drying the honeycomb ceramic at 110 ℃ for 12 hours, roasting the honeycomb ceramic at 500 ℃ for 3 hours, weighing the honeycomb ceramic, and repeating the coating process for 3 times.

[ example 26 ]

[ example 27 ]

[ example 28 ]

Comparative example 1

Preparation of active ingredients: 37.02g of lanthanum nitrate and 29.10g of cobalt nitrate are prepared into a solution, a mixed solution of sodium hydroxide and sodium carbonate is added into the solution under the condition of stirring until the pH value is 10.5, then the solution is filtered, washed, dried at 110 ℃, and roasted at 650 ℃ for 4 hours to obtain perovskite powder.

Comparative example 2

Preparation of active ingredients: a solution was prepared from 43.41g of cerium nitrate and 29.10g of cobalt nitrate, and a mixed solution of sodium hydroxide and sodium carbonate was added thereto with stirring to a pH of 10.5, followed by filtration and washing, drying at 110 ℃ and then calcination at 650 ℃ for 4 hours to obtain a perovskite powder.

Comparative example 3

Preparation of active ingredients: 48.51g of bismuth nitrate and 29.10g of cobalt nitrate are prepared into a solution, a mixed solution of sodium hydroxide and sodium carbonate is added to the solution under the condition of stirring until the pH value is 10.5, then the solution is filtered and washed, dried at 110 ℃, and then roasted at 650 ℃ for 4 hours to obtain perovskite powder.

Comparative example 4

Preparation of active ingredients: lanthanum nitrate 18.51g and cobalt nitrate 29.10g are prepared into a solution, a mixed solution of sodium hydroxide and sodium carbonate is added to the solution under the condition of stirring until the pH value is 10.5, then the solution is filtered and washed, dried at 110 ℃, and then roasted at 650 ℃ for 4 hours to obtain perovskite powder.

Comparative example 5

Preparation of active ingredients: lanthanum nitrate 29.62g, bismuth nitrate 9.70g and cobalt nitrate 29.10g are prepared into a solution, a mixed solution of sodium hydroxide and sodium carbonate is added into the solution under the condition of stirring until the pH value is 10.5, then the solution is filtered, washed, dried at 110 ℃ and roasted at 650 ℃ for 4 hours to obtain perovskite powder.

Comparative example 6

Preparation of active ingredients: a solution is prepared by 34.73g of cerium nitrate, 9.70g of bismuth nitrate and 29.10g of cobalt nitrate, a mixed solution of sodium hydroxide and sodium carbonate is added to the solution under the condition of stirring until the pH value is 10.5, then the solution is filtered, washed, dried at 110 ℃ and roasted at 650 ℃ for 4 hours to obtain perovskite powder.

Comparative example 7

Preparation of active ingredients: lanthanum nitrate 22.21g, cerium nitrate 8.68g, bismuth nitrate 9.70g and cobalt nitrate 29.10g are prepared into a solution, under the condition of stirring, a mixed solution of sodium hydroxide and sodium carbonate is added into the solution until the pH value is 10.5, then the solution is filtered, washed, dried at 110 ℃, and roasted at 650 ℃ for 4 hours to obtain perovskite powder.

Comparative example 8

Preparation of active ingredients: 28.88g of strontium nitrate and 29.10g of cobalt nitrate are prepared into a solution, a mixed solution of sodium hydroxide and sodium carbonate is added into the solution under the condition of stirring until the pH value is 10.5, then the solution is filtered, washed, dried at 110 ℃ and roasted at 650 ℃ for 4 hours to obtain perovskite powder.

[ example 29 ]

The fresh catalysts of examples 1 to 28 and comparative examples 1 to 8 were subjected to the evaluation of catalytic reaction performance under the same conditions on a fixed bed reactor catalytic reaction apparatus, and the reaction results are shown in Table 1. In this experiment, the single evaluation concentrations of the main components of the tail gas were respectively: 18000ppm of methyl acetate, 4500ppm of p-xylene, 500ppm of methyl bromide, and the concentrations of three components in a mixed sample are respectively as follows: 12000ppm of methyl acetate, 2000ppm of p-xylene and 400ppm of methyl bromide. The process conditions evaluated were: the reaction pressure is 0.05 MPa-0.10 MPa, the amount of tail gas treated by each gram of catalyst is 30L per hour, and the temperature is programmed to the reaction temperature until the catalyst is completely converted. Wherein T is₉₉The reaction temperature at which the purification rate of the component in the off-gas was 99% was shown. T of Mixed sample₉₉Expressed as the reaction temperature at which the purification of all components reached 99%. Tn indicates that the purification rate of dibromomethane at 400 ℃ is n%, and the purification rates of methyl acetate and p-xylene at this time are more than 99%.

TABLE 1

[ example 30 ]

Fresh catalyst examples 13, 20, 21, 25 and comparative example 7 were subjected to catalytic reaction performance evaluation under the same conditions on a fixed bed reactor catalytic reaction apparatus, and the reaction results are shown in table 2. In this experiment, the single evaluation concentrations of the main components of the tail gas were respectively: 18000ppm of methyl acetate, 4500ppm of p-xylene, 500ppm of methyl bromide, and the concentrations of three components in a mixed sample are respectively as follows: 12000ppm of methyl acetate, 2000ppm of p-xylene and 400ppm of methyl bromide. The process conditions evaluated were: the reaction pressure is 0.05 MPa-0.10 MPa, the amount of tail gas treated by each gram of catalyst is 50L per hour, and the temperature is programmed to the reaction temperature until the catalyst is completely converted. Wherein T is₉₉The reaction temperature at which the purification rate of the component in the off-gas was 99% was shown. T of Mixed sample₉₉Expressed as the reaction temperature at which the purification of all components reached 99%. Tn indicates that the purification rate of dibromomethane at 400 ℃ is n%, and the purification rates of methyl acetate and p-xylene at this time are more than 99%.

TABLE 2

Claims

1. The monolithic non-noble metal catalyst for treating PTA tail gas by catalytic combustion comprises an active component, a carrier coating and a honeycomb ceramic skeleton, wherein the active component is a vacancy type perovskite catalyst A_xBO₃Wherein x is 0.6-0.95, A is at least one of La, Ce and Bi, B is transition metal Co, and the carrier coating is a composite oxide of C-Al-O, wherein C is at least one of Ce, Pr and Sm.

2. Monolithic non-noble metal catalyst according to claim 1, characterized in that the perovskite catalyst A is of the active-component-deficient type_xBO₃Wherein x is 0.75-0.86.

3. The monolithic non-noble metal catalyst of claim 1, wherein a is at least two of La, Ce, Bi.

4. The monolithic non-noble metal catalyst of claim 1, wherein the molar ratio of C element to Al element is from 1:10 to 1: 20.

5. A method of making the monolithic catalyst for catalytic combustion processing of PTA exhaust gas as recited in any of claims 1-4, comprising the steps of: 1) preparing vacancy type perovskite catalyst powder; 2) preparing carrier composite oxide coating powder; 3) pretreating the honeycomb ceramic; 4) coating of a carrier coating; 5) coating of the active ingredient.

6. The production method according to claim 5, wherein production of the active component perovskite catalyst: precipitating a salt solution of a metal A, B component and an alkaline precipitator to a pH value of 10-11, filtering, washing, drying and roasting to obtain vacancy type perovskite catalyst powder.

7. The production method according to claim 5, wherein the production of the washcoat: precipitating a metal salt solution of C and Al with an alkaline precipitator to a pH value of 9-11, filtering, washing, drying and roasting to obtain composite oxide coating powder.

8. The production method according to claim 5, wherein the pretreatment of the honeycomb ceramic: drying the honeycomb ceramic at 100-120 ℃ for 4-8 h, and roasting at 300-500 ℃ for 2-5 h.

9. The method of claim 5, wherein the step 4) of applying the washcoat: firstly, dispersing carrier composite oxide powder into water to prepare a coating liquid I, dipping the honeycomb ceramic in the coating liquid I for 3-8 hours, taking out slurry remained in a blow-drying duct, drying, roasting, weighing, repeating the coating process for at least 3 times until the coating amount on a honeycomb ceramic framework in unit volume is 180-240 g/L, wherein the mass ratio of solids in the coating liquid I is 30-50%;

the step 5) coating of active components: firstly, dispersing vacancy type perovskite catalyst powder into water to prepare a coating liquid II, soaking the honeycomb ceramic loaded with the carrier in the step 4) in the coating liquid II for 3-8 hours, then taking out, blow-drying residual slurry in a pore channel, then drying, roasting, weighing, and repeating the coating process for at least 3 times until the coating amount on a honeycomb ceramic framework in unit volume is 50-100 g/L to prepare the integral non-noble metal catalyst, wherein the solid mass ratio of the coating liquid II is 30-50%.

10. A catalytic combustion method for PTA oxidized tail gas is characterized in that the PTA oxidized tail gas is contacted with the catalyst of claims 1-4, a mixture of nitrogen and oxygen or air is introduced at the temperature of 200-400 ℃, and methyl acetate, xylene and dibromomethane volatile organic compounds in the PTA oxidized tail gas are catalytically combusted to generate carbon dioxide, water, hydrogen bromide and bromine elementary substances; wherein the amount of the tail gas containing 500-25000ppm per gram of the catalyst is 5-50L per hour.