Treatment methods for catalyst production waste gas

Abstract

This invention relates to the technical field of waste gas treatment, and discloses a method for treating waste gas from catalyst production. The method includes the following steps: (a) buffering a first catalyst production waste gas generated during catalyst production to obtain a buffered waste gas stream; (b) combining the buffered waste gas stream obtained in step (a) with a second catalyst production waste gas generated during catalyst production to obtain a total production waste gas stream; and (c) combining the total production waste gas stream obtained in step (b) with air to obtain a total gas stream, wherein the calorific value of the total gas stream is 100-1300 kJ / Nm³. 3 (d) In the presence of a purification catalyst, the total gas flow obtained in step (c) is subjected to catalytic purification treatment to obtain a catalytically purified gas flow. This method can effectively treat the waste gas generated in each process step of catalyst production through normalization, reduce the content of nitrogen oxides in the production waste gas, reduce production costs, and has continuous operation capability.

Description

Technical Field

[0001] This invention relates to the technical field of waste gas treatment, and specifically to a method for treating waste gas from catalyst production. Background Technology

[0002] Chemical processes typically involve numerous operational units and complex process pathways, with varying types, concentrations, and emission paths of waste gases generated by different units or processes. For the purification of such complex waste gases, direct incineration is often employed. However, incineration is generally suitable for treating waste gases with high concentrations of organic matter. When dealing with waste gases containing medium to low concentrations of organic matter, large amounts of fuel gas are often required to maintain combustion, increasing operating costs and significantly raising carbon emissions. Therefore, direct incineration is unsuitable for treating waste gases with medium to low concentrations of organic matter. Furthermore, direct incineration is generally ineffective at treating waste gases containing nitrogen oxides (NOx), and sometimes improper process control can generate additional NOx pollution. Environmental legislation imposes stringent requirements on the purification of waste gases from chemical processes, particularly requiring these purified waste gases to be directly discharged into the atmosphere.

[0003] The production of molecular sieve catalysts is a multi-step process, typically involving crystallization, drying, molding, and calcination. Each step includes numerous operations, and the presence of raw material storage tanks results in a large amount of unorganized and intermittent emissions of waste gas throughout the entire molecular sieve catalyst production process. These waste gases usually contain different types and concentrations of organic or inorganic substances.

[0004] Waste gas from typical molecular sieve production processes usually contains unreacted raw materials, template agent decomposition products, low-boiling-point solvents, nitrogen oxides from calcination, and dust. These components can be treated using different waste gas treatment technologies. For example, selective reduction (NH3-SCR) can be used to treat waste gas containing nitrogen oxides generated during calcination; acid / alkali absorption can be used to treat waste gas containing some production raw materials; and catalytic oxidation (CO) can be used to treat waste gas containing template agent decomposition products. However, as mentioned above, using different purification methods for different process waste gases will inevitably increase the production cost of molecular sieve catalysts. Therefore, it is necessary to design a waste gas purification method that comprehensively considers both economic efficiency and practicality.

[0005] Existing research on the purification and treatment of waste gas generated throughout the entire production process of molecular sieve catalysts is relatively limited, with most studies focusing only on the treatment of waste gas generated in the calcination unit. Patent application CN10539642A discloses a method for treating molecular sieve calcination tail gas, describing a method for removing NOx from the calcination tail gas using alkaline spraying. Patent application CN105457443A focuses on the removal of dust and ammonia from molecular sieve calcination tail gas and the recovery of waste heat.

[0006] Therefore, it is still necessary to develop an economical and practical waste gas treatment method for the entire process of molecular sieve production. Summary of the Invention

[0007] The purpose of this invention is to overcome the problems existing in the prior art and provide a method for treating waste gas from catalyst production. This method can effectively treat the waste gas generated in each process step of catalyst production through normalization, reduce the content of nitrogen oxides in the waste gas, reduce production costs, and has continuous operation capability.

[0008] To achieve the above objectives, the present invention provides a method for treating catalyst production waste gas, wherein the method includes the following steps:

[0009] (a) The first catalyst production waste gas generated during the catalyst production process is buffered to obtain a buffered waste gas stream;

[0010] (b) The buffer waste gas obtained in step (a) is combined with the second catalyst production waste gas generated during the catalyst production process to obtain the total production waste gas;

[0011] (c) Combine the total production waste gas stream obtained in step (b) with air to obtain a total gas stream, wherein the calorific value of the total gas stream is 100-1300 kJ / Nm³. 3 ;

[0012] (d) In the presence of a purification catalyst, the total gas flow obtained in step (c) is subjected to catalytic purification treatment to obtain a catalytically purified gas flow.

[0013] Preferably, in step (b), the volumetric flow rate ratio of the buffered waste gas flow to the second production waste gas is 100:1-1:1, more preferably 75:1-10:1, and even more preferably 75:1-30:1.

[0014] Preferably, the calorific value of the total gas flow is 1000-50000 kJ / Nm lower than that of the total production waste gas flow. 3 Further optimization of low 5300-10000kJ / Nm 3 .

[0015] Preferably, in step (c), the flow-volume ratio of the total production waste gas flow to the air flow is 1:0.05-100, and more preferably 1:5-50.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] The method provided by this invention diverts and combines the catalyst production waste gas generated by each process step or process unit during catalyst production into a single gas stream, avoiding the defects of step-by-step processing in the prior art. Preferably, after buffering treatment, the water content in the first catalyst production waste gas can be controlled, thereby controlling the purification effect of the total production waste gas stream. Furthermore, air is introduced as a diluent gas to reduce the heat of the total production waste gas stream, keeping it within the preferred range of this invention. This avoids excessively high calorific value, which could lead to secondary pollution from the generation of by-products, while also preventing excessively low calorific value, which would fail to provide the heat required for organic matter conversion.

[0018] The method provided by this invention does not require an additional heat source. By controlling the change in calorific value during the reaction process and coordinating the reaction conditions, it can reduce the content of nitrogen oxides in the production waste gas while purifying non-methane VOCs in the exhaust gas and generating nitrogen gas, thus avoiding air pollution.

[0019] The method provided by this invention is particularly applicable to the treatment of waste gas produced during the production of SAPO molecular sieve catalysts.

[0020] The method provided by this invention saves initial investment costs and land occupation. The entire process is simple, the equipment structure is concise, and it can operate continuously and stably for a long time, thus saving operating costs. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the process flow of the present invention.

[0022] Explanation of reference numerals in the attached figures

[0023] 1- Waste gas from the first catalyst production 2- Waste gas from the second catalyst production

[0024] 3-Buffer tank 4-Buffer exhaust gas flow

[0025] 5-Total production waste gas flow 6-Fan

[0026] 7-Total airflow 8-Heat exchanger

[0027] 9-Heater 10-Catalytic purification processor

[0028] 11-Catalytic purification airflow Detailed Implementation

[0029] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0030] In this invention, the calorific value of the waste gas produced by the first catalyst and the calorific value of the waste gas produced by the second catalyst are obtained by calculation. The specific test conditions are: the content of different components is determined and then the calculation is performed according to the standard calorific value of the corresponding components.

[0031] In this invention, the calorific value of the total production waste gas flow is obtained by calculation: calorific value of the total production waste gas flow = (calorific value of the buffer waste gas flow × volumetric flow rate of the buffer waste gas flow + calorific value of the second production waste gas × volumetric flow rate of the second catalyst production waste gas) / (volumetric flow rate of the buffer waste gas flow + volumetric flow rate of the second production waste gas flow). It should be noted that the calorific value of the first catalyst production waste gas remains essentially unchanged after buffering treatment; therefore, the calorific value of the first catalyst production waste gas is considered as the calorific value of the buffer waste gas flow.

[0032] In this invention, the calorific value of the total airflow is calculated as follows: calorific value of total airflow = calorific value of total production waste gas flow / (volume flow rate of air + volume flow rate of total production waste gas flow).

[0033] In this invention, the water content is measured by gravimetric analysis. The specific test conditions are: phosphorus pentoxide is used to absorb the moisture in the gas, and the water content is calculated based on the weight difference before and after absorption.

[0034] In this invention, the content of each component in each gas stream is determined by gas chromatography. The specific test conditions are as follows: the gas stream is introduced into the gas chromatograph, and qualitative analysis is performed based on the differences in peak retention time of different components. The content of different components is calculated by comparing the peak area with that of a standard sample with a known concentration.

[0035] This invention provides a method for treating waste gas from catalyst production, wherein the method includes the following steps:

[0036] (a) The first catalyst production waste gas generated during the catalyst production process is buffered to obtain a buffered waste gas stream;

[0037] (b) The buffer waste gas obtained in step (a) is combined with the second catalyst production waste gas generated during the catalyst production process to obtain the total production waste gas;

[0038] (c) Combine the total production waste gas stream obtained in step (b) with air to obtain a total gas stream, wherein the calorific value of the total gas stream is 100-1300 kJ / Nm³. 3 ;

[0039] (d) In the presence of a purification catalyst, the total gas flow obtained in step (c) is subjected to catalytic purification treatment to obtain a catalytically purified gas flow.

[0040] The inventors of this invention discovered in their research that by combining the production waste gases generated from different units during catalyst production to obtain a total production waste gas stream, and introducing a diluent gas such as air to reduce the heat of the total gas stream, the calorific value of the total gas stream can be controlled between 100-1300 kJ / Nm³. 3 Within this range, it facilitates the subsequent catalytic purification treatment of organic matter and nitrogen oxides in the exhaust gas. On the one hand, if the calorific value is too high, side reactions are likely to occur, generating byproducts and causing secondary pollution; on the other hand, if the calorific value is too low, the reaction exothermic effect is small, and the temperature required to treat organic matter cannot be reached, requiring additional heat to be added, increasing production costs. At the same time, if the calorific value is too low, the content of organic matter such as low-concentration C and H compounds in the production exhaust gas is too low, resulting in a low reaction temperature and reduced organic matter removal efficiency.

[0041] In this invention, there is no particular limitation on the calorific value of the first catalyst production waste gas. This method is particularly suitable for treating catalyst production waste gas whose calorific value is within the range defined by this invention. Preferably, in step (a), the calorific value of the first catalyst production waste gas is 5000-50000 kJ / Nm³. 3 Further preferably 5000-10000 kJ / Nm 3 In this invention, the calorific value of the buffered waste gas is controlled by the calorific value of the waste gas produced by the first catalyst, so that the buffered waste gas is matched with the waste gas produced by the second catalyst, which facilitates the removal of organic matter in the waste gas and improves the organic matter removal rate.

[0042] In this invention, the water content of the waste gas obtained from different catalyst production units varies. Preferably, based on the content of the waste gas from the first catalyst production unit, the water content of the waste gas from the first catalyst production unit is 3.5-10% by volume, more preferably 3.5-5% by volume.

[0043] In this invention, the conditions for buffering treatment are not particularly limited, as long as the water content in the first catalyst production waste gas is controlled within the required range and the water content in the first catalyst production waste gas is reduced within the shortest possible buffering time to meet the requirements of subsequent treatment. Preferably, in step (a), the conditions for buffering treatment are such that the water content in the buffered waste gas stream is 0.5-1.5% by volume.

[0044] In this invention, the composition of the exhaust gas from the first catalyst production is not particularly limited. Preferably, in step (a), the exhaust gas from the first catalyst production contains at least one of ethylene, propylene, ethanol, acetaldehyde, and triethylamine. In this invention, the content of each component in the exhaust gas from the first catalyst production is not particularly limited. Preferably, the total content of the above components accounts for 0.01-10% by weight of the exhaust gas from the first catalyst production.

[0045] In this invention, there is no particular limitation on the calorific value of the exhaust gas from the second catalyst production process, as long as it meets the calorific value requirements of the subsequent total gas flow. Those skilled in the art can select the appropriate value based on actual needs. Preferably, in step (b), the calorific value of the exhaust gas from the second catalyst production process is 10-1000 kJ / Nm³. 3 Further preferably 500-900 kJ / Nm 3 .

[0046] In this invention, preferably, in step (b), the water content of the waste gas from the second catalyst production is 0.1-3% by volume, based on the content of the waste gas from the second catalyst production. The advantage of this preferred embodiment is that it controls the water content of the total waste gas flow.

[0047] In this invention, the composition of the exhaust gas from the second catalyst production is not particularly limited. Preferably, in step (b), the exhaust gas from the second catalyst production contains nitrogen oxides and / or triethylamine. In this invention, the specific type of nitrogen oxide is not particularly limited, and it is any nitrogen oxide known to those skilled in the art. In this invention, the content of each component in the exhaust gas from the second catalyst production is not particularly limited. Preferably, the total content of the above components accounts for 0.01-10% by weight of the exhaust gas from the second catalyst production.

[0048] In this invention, the calorific value of the total production waste gas is controlled by adjusting the calorific value and volumetric flow rate ratio of the buffer waste gas flow and the second catalyst production waste gas flow to ensure the waste gas treatment volume and treatment effect. Preferably, in step (b), the calorific value of the total production waste gas flow is 5000-50000 kJ / Nm³. 3 Further preferred is 6000-10000 kJ / Nm 3 .

[0049] In this invention, preferably, in step (b), the nitrogen oxide content in the total production waste gas flow is 2000-5000 mg / m³, based on the total volume of the waste gas flow. 3 The preferred concentration is 2500-3500 mg / m³. 3 The oxygen content is 0.1-1% by volume, preferably 0.2-0.5% by volume.

[0050] In this invention, the calorific value of the total production waste gas is controlled by the volumetric flow rate ratio of the buffer waste gas and the second catalyst production waste gas, providing a thermal basis for the removal of organic matter in the catalyst production waste gas and facilitating the removal of nitrogen oxides from the organic matter. Preferably, in step (b), the volumetric flow rate ratio of the buffer waste gas to the second catalyst production waste gas is 100:1-1:1, more preferably 75:1-10:1, and even more preferably 75:1-30:1.

[0051] In this invention, preferably, the calorific value of the total gas flow is 1000-50000 kJ / Nm lower than the calorific value of the total production waste gas flow. 3 Preferred value: low 5300-10000 kJ / Nm 3 .

[0052] In this invention, the specific oxygen content is not particularly limited. Preferably, in step (c), based on the total volume of the gas flow, the oxygen content in the total gas flow is 10-30% by volume, preferably 15-21% by volume. The advantage of this preferred embodiment is that it ensures the purification effect of the subsequent catalytic purification reaction process.

[0053] In this invention, preferably, in step (c), the calorific value of the total airflow is 200-900 kJ / Nm³. 3 .

[0054] In this invention, preferably, in step (c), the flow-volume ratio of the total production waste gas stream to the air is 1:0.05-100, more preferably 1:5-50. The advantage of this preferred embodiment is that it ensures the calorific value of the gas stream is within a suitable range for subsequent catalytic purification reactions.

[0055] In this invention, the selection range of conditions for catalytic purification is relatively wide. Preferably, in step (d), the conditions for catalytic purification include: a temperature of 200-500℃ and a reaction space velocity of 1000-100000 h⁻¹. -1 More preferably, in step (d), the conditions for the catalytic purification treatment include: a temperature of 250-450°C and a reaction space velocity of 5000-50000 h⁻¹. -1 .

[0056] In this invention, preferably, in step (d), the purification catalyst comprises a porous substrate and an active component supported on the porous substrate. The advantage of this preferred embodiment is that it increases the contact area between the catalyst and the gas, and reduces the pressure drop of the gas flow.

[0057] In this invention, there is no particular limitation on the specific type of active component, and those skilled in the art can select it according to actual needs. Preferably, the active component is selected from at least one of Group VIII metal elements, Group VIB metal elements, and Group IB metal elements, more preferably at least one of Co, Ni, Cr, Fe, Mn, and Cu, and even more preferably at least one of Co, Ni, Fe, and Cu.

[0058] In this invention, preferably, the porous substrate is selected from at least one of the following: a honeycomb cordierite substrate, a corrugated metal substrate, a porous ceramic fiber substrate, and a foam ceramic substrate.

[0059] In this invention, preferably, the porosity of the porous matrix is ​​20-60%.

[0060] In this invention, preferably, the purification catalyst further includes a binder and a molecular sieve.

[0061] In this invention, preferably, the binder is selected from at least one of alumina, silicon oxide, and transition metal oxides. More preferably, the transition metal oxide is selected from zirconium oxide and / or titanium oxide.

[0062] In this invention, preferably, the particle size D90 of the active component is 50-5000 nm.

[0063] In this invention, preferably, the particle size D90 of the molecular sieve is 10-2000 nm.

[0064] In this invention, D90 refers to the fact that 90% of the particles have a diameter below this value, which is measured by a laser particle size analyzer. The specific test conditions are: the particles are dispersed in an aqueous solvent, the particle size distribution of the particles dispersed in the water is analyzed by laser particle size analysis, and the D90 value is calculated.

[0065] In this invention, the content of each component in the purification catalyst is not particularly limited. Preferably, based on the total amount of the purification catalyst, the content of the porous substrate is 60-80% by weight, the content of the active component (calculated as oxide) is 1-15% by weight, the content of the binder is 1-10% by weight, and the content of the molecular sieve is 10-20% by weight.

[0066] In this invention, the contents of porous substrate, molecular sieve and binder in the purification catalyst are calculated by the amount of feed, and the contents of active components are obtained by analyzing the elemental contents by ICP (inductively coupled plasma spectroscopy), and then the oxide contents are obtained by conversion.

[0067] In this invention, the preparation method of the purification catalyst is not particularly limited. According to one embodiment of the present invention, the preparation method of the purification catalyst includes the following steps:

[0068] S1: Mix at least a portion of the active component precursor with an alkaline compound (preferably ammonia water) and then stir for the first time, followed by solid-liquid separation, first drying and first calcination to obtain the calcined product;

[0069] The calcined product is mixed with water (preferably deionized water) to obtain slurry A, and then slurry A is ground to obtain a slurry containing nanoparticles with a particle size D90 of 50-5000 nm.

[0070] S2: Molecular sieves with a particle size D90 of 10-2000 nm, at least part of the active component precursor, dispersant, and binder with a particle size D90 of 10-100 nm and the nanoparticle-containing slurry obtained in step S1 are mixed and stirred for a second time to obtain slurry B.

[0071] S3: Mix the slurry B obtained in step S2 with the porous substrate to obtain slurry C, and then subject slurry C to purging, second drying and second calcination to obtain purified catalyst.

[0072] The types of active components in this invention have been described above and will not be repeated here.

[0073] In this invention, preferably, in steps S1 and S2, the precursors of the active components are each independently selected from soluble salts of the respective active components, for example, at least one of cobalt nitrate, nickel nitrate, manganese nitrate, and copper nitrate. In this invention, the active components in steps S1 and S2 can be the same or different, preferably different.

[0074] In this invention, preferably, in steps S1 and S2, the precursor containing the active component is provided by a solution containing the active component precursor, and the concentration of the solution containing the active component precursor is 0.01-10 mol / L.

[0075] In this invention, preferably, in step S1, the amount of alkaline compound used is such that the pH of the mixed solution is 8-12.

[0076] In this invention, there are no particular limitations on the conditions for the first stirring in step S1. Preferably, in step S1, the first stirring time is 1-10 hours.

[0077] In this invention, there is no particular limitation on the method of solid-liquid separation in step S1, and it can be a solid separation method conventionally defined in the art, such as filtration.

[0078] In this invention, preferably, in step S1, the conditions for the first calcination include: a temperature of 150-600℃, more preferably 150-500℃, and a time of 1-10h.

[0079] In this invention, there is no particular limitation on the amount of water used in step S1. Preferably, in step S1, the amount of water used is such that the solid content of slurry A is 5-50 wt%.

[0080] In this invention, the specific types of molecular sieves and binders in step S2 have been described above and will not be repeated here.

[0081] In this invention, there is no particular limitation on the type of dispersant used in step S2. Preferably, in step S2, the dispersant is selected from at least one of ammonium polyacrylate, carboxylate polyacrylate, hydroxyl copolymer of acrylic acid, hexadecyltrimethylammonium bromide, sodium lignosulfonate, and ammonium citrate.

[0082] In this invention, there is no particular limitation on the amount of dispersant used in step S2, and those skilled in the art can select it according to actual needs.

[0083] In this invention, there are no particular limitations on the conditions for the second stirring in step S2. Preferably, in step S2, the second stirring time is 1-10 hours.

[0084] In this invention, the types and properties of porous substrates in step S3 have been described above and will not be repeated here.

[0085] In this invention, there are no particular limitations on the purging method in step S3, and those skilled in the art can choose according to actual needs.

[0086] In this invention, there are no particular limitations on the conditions for the second drying in step S3. Preferably, in step S3, the conditions for the second drying include: a temperature of 60-100°C and a time of 10-48 hours.

[0087] In this invention, the conditions for the second calcination in step S3 are not particularly limited. Preferably, the conditions for the second calcination in step S3 include: a temperature of 400-600℃ and a time of 1-10h.

[0088] In this invention, preferably, the amounts of the active component precursor, molecular sieve, porous substrate, and binder are such that, based on the total amount of the purified catalyst, the content of the porous substrate is 60-80% by weight, the content of the active component (calculated as oxide) is 1-15% by weight, the content of the binder is 1-10% by weight, and the content of the molecular sieve is 10-20% by weight.

[0089] According to a specific embodiment of the present invention, the aforementioned method of the present invention is as follows: Figure 1The process flow shown is as follows: the first catalyst production waste gas 1 is buffered in buffer tank 3 to obtain buffered waste gas stream 4. Buffered waste gas stream 4 is combined with the second catalyst production waste gas 2 to obtain total production waste gas stream 5. Fan 6 provides air, which is then combined with total waste gas stream 5 to obtain total gas stream 7. The calorific value of total gas stream 7 reaches 100-1300 kJ / Nm³. 3 Then, the total gas flow 7 passes through the heat exchanger 8 and the heater 9 in sequence and enters the catalytic purification processor 10 for catalytic purification treatment to obtain the catalytic purified gas flow 11.

[0090] The present invention will be described in detail below through embodiments.

[0091] Preparation example of purification catalyst

[0092] Preparation Example 1

[0093] S1: Preparation of nanoparticle-containing slurry: A certain volume of a mixed solution containing Co(NO3)2·6H2O and Ni(NO3)2·6H2O was taken. A 1 mol / L ammonia solution was added dropwise to the mixed solution of 0.4 mol / L Co(NO3)2·6H2O and 0.2 mol / L Ni(NO3)2·6H2O. The addition of ammonia was stopped when the pH of the solution reached 8. The mixture was then stirred thoroughly at room temperature for 3 hours, filtered, washed, dried, and calcined at 450℃ for 2 hours. The calcined powder was diluted with deionized water to prepare a slurry with a solid content of 10 wt% (100 g). The nanoparticles in the slurry were ground to a particle size of D90-800 nm using a high-speed mill and set aside for later use.

[0094] S2: Add 53.3g of ZSM-5 molecular sieve with a grain size of D90-2000nm and a certain amount of Cu(NO3)2·6H2O to the slurry containing nanoparticles obtained in step S1, so that the solid content of the slurry reaches 20wt% and the mass of Cu is 5wt% of ZSM-5. Add 1wt% (based on the amount of molecular sieve) of ammonium polyacrylate dispersant and 53.3g of Al sol with a solid content of 25wt% (D90=15nm) to the above slurry, continue stirring for 1 hour and then let it stand for use.

[0095] S3: A substrate with a porosity of 60% (80g by weight) was placed in the nanoparticle-containing slurry obtained in step S2. After removing excess slurry with compressed air, the substrate containing nanoparticles was dried in an oven at 60°C for 24 hours. After drying, it was calcined in a muffle furnace at 550°C for 4 hours to obtain the catalytic purification catalyst. The total weight of the catalyst was measured to be 114g, and the solid loading rate of the slurry obtained in S2 was 29.8wt%.

[0096] Preparation Example 2

[0097] S1: Preparation of nanoparticle-containing slurry: A certain volume of a mixed solution containing Co(NO3)2·6H2O and Ni(NO3)2·6H2O was taken. A 1 mol / L ammonia solution was added dropwise to the mixed solution of 0.4 mol / L Co(NO3)2·6H2O and 0.2 mol / L Ni(NO3)2·6H2O. The addition of ammonia was stopped when the pH of the solution reached 7.5. The mixture was then stirred thoroughly at room temperature for 3 hours, filtered, washed, dried, and calcined at 600℃ for 2 hours. The calcined powder was diluted with deionized water to prepare a slurry with a solid content of 10 wt% (100 g). The nanoparticles in the slurry were ground to a particle size of D90-800 nm using a high-speed mill and set aside for later use.

[0098] S2: Add 16.6g of ZSM-5 molecular sieve with a grain size of D90-500nm and a certain amount of Cu(NO3)2·6H2O to the slurry containing nanoparticles obtained in step S1, so that the solid content of the slurry reaches 20wt% and the mass of Cu is 5wt% of ZSM-5. Add 1wt% (based on the amount of molecular sieve) of ammonium polyacrylate dispersant and 22.1g of Al sol (D90=15nm) with a solid content of 25wt% to the above slurry, continue stirring for 1h and let it stand for later use.

[0099] S3: A substrate with a porosity of 60% (60g by weight) was placed in the nanoparticle-containing slurry obtained in step S2. After removing excess slurry with compressed air, the substrate containing nanoparticles was dried in an oven at 60°C for 24 hours. After drying, it was calcined in a muffle furnace at 550°C for 4 hours to obtain the catalytic purification catalyst. The total weight of the catalyst was measured to be 86g, and the solid loading rate of the slurry obtained in S2 was 30.2wt%.

[0100] The following examples and comparative examples are in accordance with... Figure 1 The process flow shown treats catalyst production waste gas, wherein the method includes the following steps:

[0101] (a) The first catalyst production waste gas 1 generated during the catalyst production process is buffered in buffer tank 3 to obtain buffered waste gas flow 4.

[0102] (b) The buffer waste gas flow 4 obtained in step (a) is combined with the second catalyst production waste gas 2 generated during the catalyst production process to obtain the total production waste gas flow 5;

[0103] (c) After the total production waste gas flow 5 obtained in step (b) is combined with the air provided by the fan 6, the total gas flow 7 is obtained;

[0104] (d) In the presence of a purification catalyst, the total gas flow 7 obtained in step (c) is sequentially passed through a heat exchanger 8 and a heater 9 and sent to a catalytic purification processor 10 for catalytic purification treatment to obtain a catalytic purified gas flow 11.

[0105] The purification catalyst used in Preparation Example 1 was selected in Examples 1-7.

[0106] Examples 1-6

[0107] According to such Figure 1 The process flow is shown in Table 1-3. In step (d), the catalyst purification temperature is 280℃ and the reaction space velocity is 1000 h⁻¹. -1 .

[0108] Example 7

[0109] The method is the same as in Example 1, except that the volumetric flow ratio of the buffer waste gas 4 to the second catalyst production waste gas 2 is 5:1, and the reaction conditions are shown in Tables 1-3.

[0110] Example 8

[0111] The method is the same as in Example 1, except that the total production waste gas flow 5 and the air flow volume ratio is 1:4, and the reaction conditions are shown in Tables 1-3.

[0112] Example 9

[0113] The method of Example 1 was followed, except that the purification catalyst of Preparation Example 2 was used, and the reaction conditions are shown in Tables 1-3.

[0114] Comparative Examples 1-2

[0115] The method is the same as in Example 1, except that the reaction conditions are shown in Tables 1-3.

[0116] The operating parameters involved in the above embodiments and comparative examples are shown in Tables 1-3. The experiments were conducted continuously, with data collected for 5 hours for testing. The test conditions were as follows: the treated gas was passed into gas chromatography and infrared spectroscopy to determine the content of non-methane total hydrocarbons and nitrogen oxides in the catalytic purification gas stream. The reaction results are shown in Table 4.

[0117] Table 1

[0118]

[0119] Table 2

[0120]

[0121]

[0122] Table 3

[0123]

[0124] Table 4

[0125] <![CDATA[Non-methane hydrocarbon content (mg / m 3 )]]> <![CDATA[Nitrogen oxide content (mg / m 3 )]]> Example 1 12.9 21.8 Example 2 20.5 17.2 Example 3 23.7 9.6 Example 4 33.5 28.9 Example 5 12.7 36.3 Example 6 10.8 48.2 Example 7 51.3 34.5 Example 8 10.1 97 Example 9 49.7 42.9 Comparative Example 1 88.9 95.9 Comparative Example 2 328 201

[0126] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for treating a catalyst production off-gas, characterized by, The method comprises the following steps: (a) buffering the first catalyst production exhaust gas generated in the catalyst production process to obtain a buffered exhaust gas stream; (b) combining the buffered exhaust gas stream obtained in step (a) with the second catalyst production exhaust gas generated in the catalyst production process to obtain a total production exhaust gas stream; (c) combining the total production off-gas stream from step (b) with air to obtain a total gas stream, wherein the total gas stream has a heating value of 100-1300 kJ / Nm 3 ; (d) catalytically purifying the total gas stream obtained in step (c) in the presence of a purification catalyst to obtain a catalytically purified gas stream; In step (a), the first catalyst production exhaust gas contains at least one of ethylene, propylene, ethanol, acetaldehyde and triethylamine; In step (b), the second catalyst production exhaust gas contains nitrogen oxides and / or triethylamine; In step (b), the volume flow ratio of the buffered exhaust gas stream to the second catalyst production exhaust gas is 100:1-1:1; In step (c), the volume flow ratio of the total production exhaust gas stream to the air is 1:0.05-100.

2. The method of claim 1, wherein, In step (a), the first catalyst produces an exhaust gas having a heating value of 5000-50000 kJ / Nm 3 .

3. The method of claim 2, wherein, In step (a), the first catalyst produces an exhaust gas having a heating value of 5000-10000 kJ / Nm 3 .

4. The method of claim 1, wherein, In step (a), the water content of the first catalyst production exhaust gas is 3.5-10% by volume based on the content of the first catalyst production exhaust gas.

5. The method of claim 4, wherein, In step (a), the water content of the first catalyst production exhaust gas is 3.5-5% by volume based on the content of the first catalyst production exhaust gas.

6. The method of claim 1, wherein, In step (a), the buffering conditions are such that the water content of the buffered exhaust gas stream is 0.5-1.5% by volume.

7. The method of claim 1, wherein, In step (b), the second catalyst produces an exhaust gas having a heating value of 10 to 1000 kJ / Nm 3 .

8. The method of claim 1, wherein, In step (b), the water content of the second catalyst production exhaust gas is 0.1-3% by volume based on the content of the second catalyst production exhaust gas.

9. The method of any of claims 1-8, wherein, In step (b), the total production off-gas stream has a heating value of 5000-50000 kJ / Nm 3 .

10. The method of claim 9, wherein, In step (b), the total production off-gas stream has a heating value of 6000-10000 kJ / Nm 3 .

11. The method of any one of claims 1-8, wherein, In step (b), the total amount of the nitrogen oxides in the total production exhaust gas stream is 2000 to 5000 mg / m3, and the total amount of the oxygen is 0.1 to 1 vol% based on the total amount of the total production exhaust gas stream. 3 , the total amount of the oxygen is 0.1 to 1 vol% based on the total amount of the total production exhaust gas stream.

12. The method of claim 1, wherein, In step (b), the volume flow ratio of the buffered exhaust gas stream to the second catalyst production exhaust gas is 75:1-10:

1.

13. The method of claim 12, wherein, In step (b), the volume flow ratio of the buffered exhaust gas stream to the second catalyst production exhaust gas is 75:1-30:

1.

14. The method of any one of claims 1-8, wherein, The total gas stream has a lower heating value of 1000-50000 kJ / Nm than the total production off-gas stream 3 .

15. The method of claim 14, wherein, The total gas stream has a lower heating value of 5300-10000 kJ / Nm3 than the total production off-gas stream 3 .

16. The method of any one of claims 1-8, wherein, In step (c), the oxygen content of the total gas stream is 10-30% by volume based on the total amount of the total gas stream.

17. The method of claim 16, wherein, In step (c), the oxygen content of the total gas stream is 15-21% by volume based on the total amount of the total gas stream.

18. The method of any one of claims 1-8, wherein, In step (c) the total gas stream has a heating value of 200-900 kJ / Nm 3 .

19. The method of claim 1, wherein, In step (c), the volume flow ratio of the total production exhaust gas stream to the air is 1:5-50.

20. The method of any one of claims 1-8, wherein, In step (d), the catalytic purification treatment is carried out at a temperature of 200 to 500°C and a reaction space velocity of 1000 to 100000 h -1 .

21. The method of claim 20, wherein, In step (d), the catalytic purification treatment is carried out at a temperature of 250 to 450°C and a reaction space velocity of 5,000 to 50,000 h -1 .

22. The method of claim 1, wherein, In step (d), the purification catalyst comprises a porous substrate and an active component supported on the porous substrate.

23. The method of claim 22, wherein, In step (d), the active component is selected from at least one of Group VIII metal elements, Group VIB metal elements and Group IB metal elements.

24. The method of claim 23, wherein, In step (d), the active component is at least one of Co, Ni, Cr, Fe, Mn and Cu.

25. The method of claim 22, wherein, In step (d), the porous substrate is selected from at least one of honeycomb cordierite material substrate, metal corrugated plate substrate, porous ceramic fiber substrate and foam ceramic substrate.

26. The method of claim 22, wherein, In step (d), the porosity of the porous substrate is 20-60%.

27. The method of claim 22, wherein, In step (d), the purification catalyst further comprises a binder and a molecular sieve.

28. The method of claim 27, wherein, In step (d), the binder is selected from at least one of alumina, silica and transition metal oxide.

29. The method of claim 22, wherein, In step (d), the particle size D90 of the active component is 50-5000 nm.

30. The method of claim 27, wherein, In step (d), the particle size D90 of the molecular sieve is 10-2000 nm.

31. The method of any one of claims 22-30, wherein, The content of the porous substrate is 60-80% by weight, the content of the active component is 1-15% by weight as calculated as the oxide, the content of the binder is 1-10% by weight, and the content of the molecular sieve is 10-20% by weight, based on the total amount of the purification catalyst.

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