Catalyst production waste gas treatment method

Abstract

The invention relates to the technical field of waste gas treatment, and discloses a treatment method of catalyst production waste gas. The method comprises the following steps: (a) carrying out buffer treatment on first catalyst production waste gas generated in a catalyst production process to obtain a buffer waste gas flow; (b) converging the buffer waste gas flow obtained in the step (a) with a second catalyst production waste gas generated in the catalyst production process to obtain a total production waste gas flow; (c) combining the total production waste gas stream obtained in step (b) with air to obtain a total gas stream, the total gas stream having a calorific value of 100-1300 kJ / Nm3; and (d) in the presence of a purification catalyst, carrying out catalytic purification treatment on the total gas flow obtained in the step (c) to obtain a catalytic purified gas flow. According to the method, waste gas generated in each process step in the catalyst production process can be effectively treated in a normalization mode, the content of nitric oxide in the produced waste gas is reduced, the production cost is reduced, and continuous operability is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of waste gas treatment, and in particular to a method for treating waste gas produced by catalyst production. Background Art

[0002] Chemical processes usually involve many operating units and complex process paths. The types, concentrations and emission processes of waste gases generated by different units or process operations are different. For the purification of waste gases with complex working conditions mentioned above, direct incineration is often used. However, incineration is usually suitable for the purification of waste gases with higher concentrations of organic matter. When facing the treatment of waste gases with medium and low concentrations of organic matter, a large amount of fuel gas is often required to maintain its combustion state. This not only increases the operating cost, but also greatly increases carbon emissions. Therefore, direct incineration is not suitable for the treatment of waste gases with medium and low concentrations of organic matter. In addition, direct incineration is usually not effective for the treatment of waste gases containing nitrogen oxides (NOx), and sometimes additional nitrogen oxide pollution is generated due to improper process control. Environmental legislation has put forward very strict requirements for the purification of waste gases from chemical processes, especially when these purified waste gases need to be discharged directly into the atmosphere.

[0003] The production of molecular sieve catalysts is a multi-step process, usually involving multiple process steps such as crystallization, drying, molding, and calcination. Each process step includes many operation processes. In addition, the existence of raw material storage tanks leads to a large amount of unorganized and intermittent exhaust gas in the entire molecular sieve catalyst production process. These exhaust gases usually contain organic or inorganic substances of different types and concentrations.

[0004] The waste gas from the typical molecular sieve production process usually contains unreacted raw materials, decomposition products of template agents, low-boiling point solvents, nitrogen oxides and dust produced by roasting, etc. Different waste gas treatment technologies can be used to treat the above components separately. For example, the waste gas containing nitrogen oxides produced by the roasting process can be treated by selective reduction (NH3-SCR); the waste gas containing part of the production raw materials can be treated by acid / base absorption; and the waste gas containing decomposition products of template agents can be treated by catalytic oxidation (Catalytic Oxidation, CO). However, as shown above, if different purification treatment methods are adopted for different process waste gases, the production cost of molecular sieve catalysts will inevitably increase. Therefore, it is necessary to design a waste gas purification treatment method that comprehensively considers economy and practicality.

[0005] In the prior art, the research on the purification of waste gas generated by the entire production process of molecular sieve catalysts is relatively limited, and most of them only focus on the treatment of waste gas generated by the roasting operation unit. Patent application CN10539642A discloses a method for treating molecular sieve roasting tail gas, which describes a method for removing NOx from the roasting tail gas by spraying alkaline solution. Patent application CN105457443A focuses on the removal of dust and ammonia substances in molecular sieve roasting tail gas and the recovery of waste heat.

[0006] Therefore, there is still a need 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 the present invention is to overcome the problems existing in the prior art and to provide a method for treating waste gas produced by catalyst production. The method can effectively treat the waste gas generated by each process step in the catalyst production process in a normalized manner, reduce the content of nitrogen oxides in the production waste gas, reduce production costs and have continuous operability.

[0008] In order to achieve the above object, the present invention provides a method for treating waste gas produced by catalyst, wherein the method comprises the following steps:

[0009] (a) buffering the first catalyst production waste gas generated in the catalyst production process to obtain a buffer waste gas flow;

[0010] (b) combining the buffered waste gas stream obtained in step (a) with the second catalyst production waste gas generated in the catalyst production process to obtain a total production waste gas stream;

[0011] (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 / Nm 3 ;

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

[0013] Preferably, in step (b), the volume flow ratio of the buffer 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 stream is 1000-50000 kJ / Nm lower than the calorific value of the total process waste gas stream. 3 , further preferably lower than 5300-10000 kJ / Nm 3 .

[0015] Preferably, in step (c), the flow volume ratio of the total production waste gas flow to the air 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 the present invention collects and diverts the catalyst production waste gas generated by each process step or process treatment unit in the catalyst production process, and merges them into one airflow, thereby avoiding the defects of step-by-step treatment in the prior art; preferably, after the first catalyst production waste gas is buffered, the water content in the first catalyst production waste gas can be controlled, thereby controlling the purification treatment effect of the total production waste gas flow; further, air is introduced as a dilution gas to reduce the heat of the total production waste gas flow so that it is within the preferred range of the present invention, avoiding too high a calorific value, resulting in secondary pollution caused by the generation of by-products, and at the same time, avoiding too low a calorific value, failing to provide the heat required by organic matter, and failing to convert the organic matter.

[0018] The method provided by the present invention does not require the introduction of an additional heat source. By controlling the change in calorific value during the reaction and coordinating the reaction conditions, the content of nitrogen oxides in the production waste gas can be reduced while purifying the non-methane hydrocarbon VOCs in the tail gas, generating nitrogen and avoiding air pollution.

[0019] The method provided by the invention is particularly suitable for treating waste gas produced during the production process of SAPO molecular sieve catalyst.

[0020] The method provided by the present invention saves initial investment cost and land occupation, the entire process flow is simple, the equipment structure is concise, and it can operate continuously and stably for a long time, thus saving operation cost. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0022] Description of Reference Numerals

[0023] 1- The first catalyst produces waste gas 2- The second catalyst produces waste gas

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

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

[0026] 7-Total airflow 8-Heat exchanger

[0027] 9- Heater 10- Catalytic purification processor

[0028] 11-Catalytic purification of air flow DETAILED DESCRIPTION

[0029] The endpoints and any values ​​of the ranges disclosed in this article 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 each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0030] In the present 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 measured by calculation method, and the specific test conditions are: after measuring the content of different components, they are calculated according to the standard calorific value of the corresponding components.

[0031] In the present invention, the calorific value of the total production waste gas flow is obtained by calculation, and the calorific value of the total production waste gas flow = (calorific value of the buffer waste gas flow × volume flow of the buffer waste gas flow + calorific value of the second production waste gas × volume flow of the second catalyst production waste gas) / (volume flow of the buffer waste gas flow + volume flow of the second production waste gas). It should be noted that the calorific value of the first catalyst production waste gas is basically not changed after buffering treatment. Therefore, the calorific value of the first catalyst production waste gas is regarded as the calorific value of the buffer waste gas flow.

[0032] In the present invention, the calorific value of the total airflow is obtained by calculation, and the calorific value of the total airflow=the calorific value of the total production waste gas flow / (the volume flow of air+the volume flow of the total production waste gas flow).

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

[0034] In the present invention, the content of each component in each gas flow is measured by gas chromatography, and the specific test conditions are: the gas flow is passed into the gas chromatograph, and the qualitative analysis is performed according to the difference in peak retention time of different components, and the content of different components is calculated by comparing the peak area with the standard sample of known concentration.

[0035] The present invention provides a method for treating waste gas produced by catalyst production, wherein the method comprises the following steps:

[0036] (a) buffering the first catalyst production waste gas generated in the catalyst production process to obtain a buffer waste gas flow;

[0037] (b) combining the buffered waste gas stream obtained in step (a) with the second catalyst production waste gas generated in the catalyst production process to obtain a total production waste gas stream;

[0038] (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 / Nm 3 ;

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

[0040] The inventors of the present invention have found in their research that the production waste gases generated by different units in the catalyst production process are combined to obtain a total production waste gas flow, and a dilution gas such as air is introduced to reduce the heat of the total gas flow, so that the calorific value of the total gas flow is controlled at 100-1300 kJ / Nm 3 The range is convenient for the subsequent catalytic purification of organic matter and nitrogen oxides in the tail gas. On the one hand, if the calorific value is too large, side reactions are likely to occur, generating by-products and causing secondary pollution; on the other hand, if the calorific value is too small, the reaction exotherm is small, and the temperature required for treating organic matter cannot be reached, requiring additional heat, increasing production costs. At the same time, if the calorific value is too small, the content of organic matter in the production waste gas, such as low-concentration C and H compounds, is too low, resulting in too low reaction temperature, which reduces the removal effect of organic matter.

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

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

[0043] In the present invention, there is no particular limitation on the conditions for the buffer treatment, 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 buffer time to meet the needs of subsequent treatment. Preferably, in step (a), the buffer treatment conditions are such that the water content in the buffer waste gas stream is 0.5-1.5% by volume.

[0044] In the present invention, there is no particular limitation on the composition of the first catalyst production waste gas. Preferably, in step (a), the first catalyst production waste gas contains at least one of ethylene, propylene, ethanol, acetaldehyde and triethylamine. In the present invention, there is no particular limitation on the content of each component in the first catalyst production waste gas. Preferably, the total content of the above components accounts for 0.01-10% by weight of the first catalyst production waste gas.

[0045] In the present invention, there is no particular limitation on the calorific value of the waste gas produced by the second catalyst, as long as it meets the calorific value requirements of the subsequent total gas flow, and those skilled in the art can select it according to actual needs. Preferably, in step (b), the calorific value of the waste gas produced by the second catalyst is 10-1000 kJ / Nm 3 , more preferably 500-900 kJ / Nm 3 .

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

[0047] In the present invention, there is no particular limitation on the composition of the second catalyst production waste gas. Preferably, in step (b), the second catalyst production waste gas contains nitrogen oxides and / or triethylamine. In the present invention, there is no particular limitation on the specific types of nitrogen oxides, which are nitrogen oxides well known to those skilled in the art. In the present invention, there is no particular limitation on the content of each component in the second catalyst production waste gas. Preferably, the total content of the above components in the second catalyst production waste gas accounts for 0.01-10 weight %.

[0048] In the present invention, the calorific value of the total production waste gas flow is regulated by controlling the calorific value and volume flow ratio of the buffer waste gas flow and the second catalyst production waste gas flow to ensure the waste gas treatment amount and treatment effect. Preferably, in step (b), the calorific value of the total production waste gas flow is 5000-50000 kJ / Nm 3 , further preferably 6000-10000 kJ / Nm 3 .

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

[0050] In the present invention, the calorific value of the total production waste gas flow is controlled by the volume flow ratio of the buffer waste gas flow and the second catalyst production waste gas, providing a heat basis for the removal of organic matter in the catalyst production waste gas, and facilitating the removal of nitrogen oxides in the organic matter. Preferably, in step (b), the volume flow ratio of the buffer waste gas flow 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 the present invention, preferably, the calorific value of the total gas stream is 1000-50000 kJ / Nm lower than the calorific value of the total production waste gas stream. 3 , preferably low 5300-10000kJ / Nm 3 .

[0052] In the present invention, there is no particular limitation on the specific content of oxygen. Preferably, in step (c), based on the total amount of the total gas flow, the content of oxygen in the total gas flow is 10-30% by volume, preferably 15-21% by volume. The advantage of adopting this preferred embodiment is to ensure the purification effect of the subsequent catalytic purification reaction process.

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

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

[0055] In the present invention, the conditions for catalytic purification treatment can be selected in a wide range. Preferably, in step (d), the conditions for catalytic purification treatment include: a temperature of 200-500°C, a reaction space velocity of 1000-100000h -1 Further preferably, in step (d), the conditions of the catalytic purification treatment include: a temperature of 250-450°C, a reaction space velocity of 5000-50000h -1 .

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

[0057] In the present 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 more preferably at least one of Co, Ni, Fe and Cu.

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

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

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

[0061] In the present invention, preferably, the binder is selected from at least one of aluminum oxide, silicon oxide and transition metal oxide. Preferably, the transition metal oxide is selected from zirconium oxide and / or titanium oxide.

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

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

[0064] In the present invention, D90 means that 90% of the particles have a particle size 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 water is analyzed by laser particle size analysis, and the D90 value is calculated.

[0065] In the present invention, there is no particular limitation on the content of each component in the purification catalyst. 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 in terms of 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 the present invention, the contents of porous substrate, molecular sieve and binder in the purification catalyst are calculated by feeding amount, and the content of active components is analyzed by ICP (inductively coupled plasma spectroscopy) to obtain the content of oxides through conversion.

[0067] In the present invention, there is no particular limitation on the preparation method of the purification catalyst. According to one embodiment of the present invention, the preparation method of the purification catalyst comprises the following steps:

[0068] S1: mixing at least part of the active component precursor with an alkaline compound (preferably aqueous ammonia) and performing a first stirring, and then performing solid-liquid separation, a first drying and a first calcination to obtain a calcined product;

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

[0070] S2: mixing a molecular sieve with a particle size D90 of 10-2000 nm, at least part of the active component precursor, a dispersant, a binder with a particle size D90 of 10-100 nm, and the slurry containing nanoparticles obtained in step S1, and performing a second stirring to obtain slurry B;

[0071] S3: Slurry B obtained in step S2 is mixed with the porous substrate to obtain slurry C, and then the slurry C is purged, second dried and second calcined to obtain a purified catalyst.

[0072] In the present invention, the types of active components have been described in the above content and will not be repeated here.

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

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

[0075] In the present invention, preferably, in step S1, the amount of the alkaline compound used makes the pH of the mixed solution be 8-12.

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

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

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

[0079] In the present 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 the present invention, in step S2, the specific types of molecular sieve and binder have been described in the above content and will not be repeated here.

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

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

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

[0084] In the present invention, in step S3, the type and properties of the porous substrate have been described in the above content and will not be repeated here.

[0085] In the present invention, there is no particular limitation on the purging method in step S3, and those skilled in the art may select the method according to actual needs.

[0086] In the present invention, there is no particular limitation 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 the present invention, there is no particular limitation on the conditions for the second calcination in step S3. Preferably, in step S3, the conditions for the second calcination include: a temperature of 400-600°C and a time of 1-10 hours.

[0088] In the present invention, preferably, the active component precursor, molecular sieve, porous substrate and binder are used in such an amount that, in the prepared purification catalyst, 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 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 in the figure is as follows: the first catalyst production waste gas 1 is buffered by the buffer tank 3 to obtain a buffer waste gas flow 4, the buffer waste gas flow 4 is combined with the second catalyst production waste gas 2 to obtain a total production waste gas flow 5, the fan 6 provides air, and the air is combined with the total production waste gas flow 5 to obtain a total gas flow 7, and the calorific value of the total gas flow 7 reaches 100-1300 kJ / Nm 3 Then, the total airflow 7 enters the catalytic purification processor 10 through the heat exchanger 8 and the heater 9 in sequence for catalytic purification treatment to obtain a catalytic purified airflow 11.

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

[0091] Preparation example of purification catalyst

[0092] Preparation Example 1

[0093] S1: Preparation of slurry containing nanoparticles: Take a certain volume of mixed solution containing Co(NO3)2·6H2O and Ni(NO3)2·6H2O, add 1 mol / L ammonia solution drop by drop to the mixed solution of 0.4 mol / L Co(NO3)2·6H2O and 0.2 mol / L Ni(NO3)2·6H2O, and stop adding ammonia solution when the pH of the solution reaches 8. Then, stir well at room temperature for 3 hours, filter, wash, dry, and calcine at 450°C for 2 hours. The calcined powder is prepared into a slurry with a solid content of 10wt% with deionized water, totaling 100g, and the particle size of the nanoparticles in the slurry is ground to D90-800nm ​​using a high-speed sand grinder, and set aside for use.

[0094] S2: Add 53.3 g of ZSM-5 molecular sieve with a grain size of D90-2000 nm 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 20 wt% and the mass of Cu is 5 wt% of ZSM-5. Add 1 wt% (based on the amount of molecular sieve) of polyacrylate ammonium salt dispersant and 53.3 g of Al sol with a solid content of 25 wt% (D90=15 nm) to the above slurry, continue stirring for 1 hour and then place for use.

[0095] S3: Place a substrate (weight 80g) with a porosity of 60% in the slurry containing nanoparticles obtained in step S2, blow off the excess slurry with compressed air, and then place the substrate containing nanoparticles in an oven at 60°C for 24 hours. After drying, calcine at 550°C in a muffle furnace for 4 hours to obtain a catalytic purification catalyst. The total weight of the catalyst is measured to be 114g, and the solid loading rate of the slurry obtained in S2 is 29.8wt%.

[0096] Preparation Example 2

[0097] S1: Preparation of slurry containing nanoparticles: Take a certain volume of mixed solution containing Co(NO3)2·6H2O and Ni(NO3)2·6H2O, add ammonia solution with a concentration of 1 mol / L dropwise to the mixed solution of Co(NO3)2·6H2O with a concentration of 0.4 mol / L and Ni(NO3)2·6H2O with a concentration of 0.2 mol / L, and stop adding ammonia solution when the pH of the solution reaches 7.5. Then, stir well at room temperature for 3 hours, filter, wash, dry, and roast at 600°C for 2 hours. The roasted powder is prepared into a slurry with a solid content of 10wt% with deionized water, totaling 100g, and the particle size of the nanoparticles in the slurry is ground to D90-800nm ​​using a high-speed sand grinder, and set aside for use.

[0098] S2: Add 16.6 g of ZSM-5 molecular sieve with a grain size of D90-500 nm 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 20 wt% and the mass of Cu is 5 wt% of ZSM-5. Add 1 wt% (based on the amount of molecular sieve) of polyacrylate ammonium salt dispersant and 22.1 g of Al sol (D90=15 nm) with a solid content of 25 wt% to the above slurry, continue stirring for 1 hour and then place for use.

[0099] S3: Place a substrate (weight 60g) with a porosity of 60% in the slurry containing nanoparticles obtained in step S2, blow off the excess slurry with compressed air, and then place the substrate containing nanoparticles in an oven at 60°C for 24 hours. After drying, calcine at 550°C in a muffle furnace for 4 hours to obtain a catalytic purification catalyst. The total weight of the catalyst is measured to be 86g, and the solid loading rate of the slurry obtained in S2 is 30.2wt%.

[0100] The following examples and comparative examples are as follows Figure 1 The process flow shown is for treating catalyst production waste gas, wherein the method comprises the following steps:

[0101] (a) buffering the first catalyst production waste gas 1 generated in the catalyst production process in a buffer tank 3 to obtain a buffer waste gas flow 4;

[0102] (b) combining the buffer waste gas stream 4 obtained in step (a) with the second catalyst production waste gas 2 generated in the catalyst production process to obtain a total production waste gas stream 5;

[0103] (c) combining the total production waste gas flow 5 obtained in step (b) with the air provided by the blower 6 to obtain a total gas flow 7;

[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 catalytically purified gas flow 11.

[0105] In Examples 1-7, the purification catalyst in Preparation Example 1 was selected.

[0106] Examples 1-6

[0107] According to Figure 1 The process flow is shown in Table 1-3. The reaction parameters of each step are shown in Table 1-3. In step (d), the catalyst purification treatment temperature is 280°C and the reaction space velocity is 1000h -1 .

[0108] Example 7

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

[0110] Example 8

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

[0112] Example 9

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

[0114] Comparative Example 1-2

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

[0116] The operating parameters involved in the above examples and comparative examples are shown in Tables 1-3. The test was carried out continuously, and the test was collected for 5 hours. The test conditions were: the treated gas was passed into gas chromatography and infrared spectroscopy respectively to measure the content of non-methane total hydrocarbons and nitrogen oxides in the catalytic purification gas flow. 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 are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for treating waste gas from catalyst production, characterized in that: The method comprises the following steps: (a) buffering the first catalyst production waste gas generated in the catalyst production process to obtain a buffer waste gas flow; (b) combining the buffered waste gas stream obtained in step (a) with the second catalyst production waste gas generated in the catalyst production process to obtain a total production waste gas stream; (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 / Nm 3 ; (d) subjecting the total gas flow obtained in step (c) to catalytic purification in the presence of a purification catalyst to obtain a catalytically purified gas flow.

2. The method according to claim 1, wherein: In step (a), the calorific value of the exhaust gas produced by the first catalyst is 5000-50000 kJ / Nm 3 , preferably 5000-10000 kJ / Nm 3 ; Preferably, based on the content of the first catalyst production waste gas, the water content of the first catalyst production waste gas is 3.5-10% by volume, and more preferably 3.5-5% by volume; Preferably, in step (a), the buffer treatment conditions are such that the water content in the buffered waste gas stream is 0.5-1.5% by volume; Preferably, in step (a), the first catalyst produces waste gas containing at least one of ethylene, propylene, ethanol, acetaldehyde and triethylamine.

3. The method according to claim 1 or 2, wherein: In step (b), the calorific value of the waste gas produced by the second catalyst is 10-1000 kJ / Nm 3 ; Preferably, in step (b), the water content of the second catalyst production waste gas is 0.1-3 volume % based on the content of the second catalyst production waste gas; Preferably, in step (b), the second catalyst produces waste gas containing nitrogen oxides and / or triethylamine.

4. The method according to any one of claims 1 to 3, wherein: In step (b), the calorific value of the total production waste gas flow is 5000-50000 kJ / Nm 3 , preferably 6000-10000 kJ / Nm 3 ; Preferably, in step (b), based on the total amount of the total production waste gas stream, the content of nitrogen oxides in the total production waste gas stream is 2000-5000 mg / m 3 , the oxygen content is 0.1-1 volume %; Preferably, in step (b), the volume flow ratio of the buffer exhaust gas flow to the second catalyst production exhaust gas is 100:1-1:1, more preferably 75:1-10:1, and even more preferably 75:1-30:

1.

5. The method according to any one of claims 1 to 4, wherein: The calorific value of the total gas stream is 1000-50000 kJ / Nm lower than the calorific value of the total production waste gas stream 3 , preferably low 5300-10000kJ / Nm 3 .

6. The method according to any one of claims 1 to 5, wherein: In step (c), based on the total amount of the total gas flow, the oxygen content in the total gas flow is 10-30% by volume, preferably 15-21% by volume.

7. The method according to any one of claims 1 to 6, wherein: In step (c), the calorific value of the total airflow is 200-900 kJ / Nm 3 ; Preferably, in step (c), the flow volume ratio of the total production waste gas flow to the air is 1:0.05-100, preferably 1:5-50.

8. The method according to any one of claims 1 to 7, wherein: In step (d), the conditions of the catalytic purification treatment include: a temperature of 200-500°C, a reaction space velocity of 1000-100000h -1 ; Preferably, in step (d), the conditions for the catalytic purification treatment include: a temperature of 250-450°C, a reaction space velocity of 5000-50000h -1 .

9. The method according to any one of claims 1 to 8, wherein: In step (d), the purification catalyst comprises a porous substrate and an active component supported on the porous substrate; Preferably, the active component is selected from at least one of Group VIII metal elements, Group VIB metal elements and Group IB metal elements, and more preferably at least one of Co, Ni, Cr, Fe, Mn and Cu; Preferably, the porous substrate is selected from at least one of a honeycomb cordierite substrate, a metal corrugated plate substrate, a porous ceramic fiber substrate and a foam ceramic substrate; Preferably, the porosity of the porous matrix is ​​20-60%; Preferably, the purification catalyst further comprises a binder and a molecular sieve; Preferably, the binder is selected from at least one of aluminum oxide, silicon oxide and transition metal oxide; Preferably, the particle size D90 of the active component is 50-5000nm; Preferably, the particle size D90 of the molecular sieve is 10-2000 nm.

10. The method according to claim 9, wherein: 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 in terms of 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.

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