Process and apparatus for the regeneration of an acrylonitrile catalyst

Abstract

The present application relates to a kind of acrylonitrile catalyst regeneration preparation method, and waste acrylonitrile catalyst is sent into calcination system, and after calcination, powder material is obtained by being handled through crushing system;Powder material is sent into reaction system with hydrofluoric acid, and filtrate and filter residue are obtained by filtering, and filter residue is heated to remove hydrofluoric acid and obtain solid material;Solid material is dissolved in nitric acid to obtain nitric acid mixed salt, and the pH of nitric acid mixed salt is adjusted to 2, and mixed solution is obtained;Sample is taken in mixed solution, sample is detected and the amount of required active component is calculated, and the corresponding missing active component is supplemented in mixed solution, and mixed salt is aged to obtain mixed salt;Mixed salt is mixed with stable ammonia type silica sol containing stabilizer to prepare slurry, and slurry is sent into spray drying system, and solid powder with water content less than 0.5% is formed;After calcination, acrylonitrile catalyst is obtained.The present application also provides a device for implementing the above method.The method of the present application is environmentally friendly and pollution-free, and the performance of the prepared product is equivalent to that of the original catalyst.

Description

Technical Field

[0001] This invention belongs to the field of catalyst regeneration technology, and specifically relates to a method and apparatus for the regeneration of acrylonitrile catalyst. Background Technology

[0002] Acrylonitrile, a core monomer for synthetic fibers, synthetic rubber, and engineering plastics, is experiencing continuous expansion in both global production capacity and market demand. It is projected that by 2030, China's total acrylonitrile production capacity will exceed 6 million tons per year, driving annual catalyst demand to over 25,000 tons. Currently, over 90% of the world's acrylonitrile is produced via the propylene ammoxidation process. This process relies heavily on molybdenum-bismuth-iron or antimony-iron catalysts, whose activity, selectivity, and lifespan directly determine the plant's operating efficiency and product cost. These catalysts must withstand reaction temperatures of 425-440℃ and complex feed gas environments during industrial operation, inevitably leading to deactivation and a spent catalyst generation rate of 80%-90%.

[0003] The core reasons for catalyst deactivation include several factors: First, trace amounts of sulfides (such as H2S and COS) in the feed gas combine with the active sites on the catalyst surface, leading to sulfur poisoning, accompanied by carbon deposits that clog pores. Second, moisture erosion during the reaction process causes the loss or structural degradation of active components (such as molybdenum, bismuth, and iron), which is the main cause of deactivation of iron-based catalysts. Third, prolonged high-temperature environments lead to catalyst particle sintering, a decrease in specific surface area, and side reactions caused by impurities in the feedstock that contaminate the active sites. Direct landfilling of deactivated catalysts not only wastes precious metal resources such as molybdenum and nickel, but their heavy metal content also causes soil and water pollution. According to the "National Hazardous Waste List," such spent catalysts have been included in the scope of hazardous waste management, highlighting the increasing pressure on environmental disposal.

[0004] To address the dual challenges of catalyst consumption and environmental remediation, spent catalyst regeneration technology has become a hot research topic in the industry. The cost of regenerated catalysts is only 30%-50% of that of newly manufactured products, and it enables the recycling of precious metal resources, possessing significant economic and environmental value. Existing regeneration technologies mainly include high-temperature roasting, etc.: High-temperature roasting removes carbon deposits through incineration, but it is difficult to repair the loss of active components, and its energy consumption is as high as 800-1000℃, easily causing secondary damage to the catalyst structure.

[0005] With the continuous increase in new acrylonitrile plants and the ongoing upgrades and renovations of older plants, the amount of acrylonitrile catalyst used is also increasing. This results in the generation of nearly several thousand tons of waste acrylonitrile catalyst each year. Acrylonitrile catalyst contains rare earth and other metal elements, and its indiscriminate disposal or treatment as hazardous waste is undoubtedly a waste. Therefore, the research and reuse of waste acrylonitrile catalyst is of profound significance. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this application provides a method for regenerating and preparing acrylonitrile catalysts, comprising the following steps: ① The waste acrylonitrile catalyst is fed into the roasting system for roasting. After roasting, it is processed by the pulverizing system to obtain powdered material with a particle size of less than 800 mesh. ② The powdered material and hydrofluoric acid are fed into the reaction system. After the powdered material and hydrofluoric acid react fully in the reaction system, the mixture is filtered to obtain filtrate and filter residue. The filtrate is recovered as hydrofluoric acid, and the filter residue is heated to remove hydrofluoric acid to obtain solid material. The hydrofluoric acid removed from the filter residue is recovered. ③ Dissolve the solid material in nitric acid to obtain a mixed nitrate salt. Adjust the pH of the mixed nitrate salt to 2 to obtain a mixed solution. ④ Take a sample from the mixed solution, send the sample into the detection system to obtain the detection result, and compare the detection result with A. a B b C c D d Ni e Fe f Bi g Mo h O i The amount of missing active components was compared and calculated, and the corresponding missing active components were added to the mixed solution. The solution was then aged until the solid content of the mixed salt was 45%–65%. ⑤ A slurry is prepared by mixing a mixed salt with a solid content of 45%-65% with an ammonia-stabilized silica sol containing a stabilizer, wherein the stabilizer is an ammonia-ammonium chloride buffer solution; ⑥ The slurry is fed into a spray drying system, and the inlet air temperature is controlled at 350-400℃ and the outlet air temperature is controlled at 150-200℃. After spray drying, a solid powder with a water content of less than 0.5% is formed. ⑦ The solid powder is fed into a finished product roasting system for roasting, and after roasting, a product with the chemical formula X%[A] is obtained. a B b C c D d Ni e Fe f Bi g Mo h O i Acrylonitrile catalyst with ]+Y%SiO2; Wherein, A is selected from at least one of Cr and Mn, B is selected from at least one of Mg, Zn, Ca, K, and Cs, C is selected from at least one of Ce, Pr, and Nd, and D is selected from at least one of P, W, B, Cu, Sn, Ge, and Cr. Here, B refers to boron, not B selected from at least one of Mg, Zn, Ca, K, and Cs; a is 0.03–0.5, b is 0.5–5, c is 0.1–1.1, d is 0.1–0.9, e is 1–10, f is 1–5, g is 0.1–1, h is 8–16, and i is the number of oxygen atoms required to satisfy the oxidation states of each element in the chemical formula. X is between 40 and 60, and X + Y = 100.

[0007] The waste acrylonitrile catalyst in this invention is a catalyst with an acrylonitrile yield of less than 70%.

[0008] Acrylonitrile yield (%) = (Number of moles of acrylonitrile produced / Number of moles of propylene fed) × 100% Preferably, the slurry in step ⑤ has a viscosity of 200-400 mPa·s, a solid content of 34-45%, and a specific gravity of 1.2-1.5 g / cm³. 3 .

[0009] Preferably, the roasting temperature in steps ① and ⑦ is 600-650℃, the roasting time is 4-8 hours, and oxygen is continuously introduced during the roasting process.

[0010] Preferably, the reaction time between the powdered material and hydrofluoric acid in step ② is 8-16 hours in the reaction system. During the reaction, the stirring rate of the stirring device is 100-300 r / min.

[0011] Preferably, step ④ involves replenishing the mixed solution with the corresponding missing active component, which is in the form of nitrate or oxide.

[0012] Preferably, the mass ratio of the waste acrylonitrile catalyst to the hydrofluoric acid is 1:5.

[0013] Another object of the present invention is to provide an apparatus for implementing the above-described method for regenerating and preparing acrylonitrile catalyst, comprising a calcination system, a pulverizing system, a reaction system, a detection system, a spray drying system, and a finished product calcination system; The roasting system and the finished product roasting system are roasting furnaces with oxygen introduction structures; The pulverizing system is an air jet mill, and the feed end of the air jet mill is connected to the discharge end of the roasting furnace of the roasting system. The reaction system includes a reactor with an external circulation pipeline, an active component replenishment tank, and a hydrofluoric acid addition tank. The reactor is equipped with a stirring device, a material inlet and a hydrofluoric acid inlet at the top, and a discharge outlet at the bottom. A disperser is installed on the external circulation pipeline. The material inlet is connected to the active component replenishment tank, and the hydrofluoric acid inlet is connected to the hydrofluoric acid addition tank. A first hydrofluoric acid recovery pipeline and a second hydrofluoric acid recovery pipeline are also installed between the reactor and the hydrofluoric acid addition tank. A vibrating filter is installed on the first hydrofluoric acid recovery pipeline, and a hydrofluoric acid absorption pump is installed on the second hydrofluoric acid recovery pipeline. The spray drying system is a spray dryer, whose feed end is connected to the discharge end of the reactor. The spray dryer is equipped with an inlet air temperature controller and an outlet air temperature controller.

[0014] Preferably, the detection system is an ICP detection system.

[0015] The acrylonitrile production process requires ammonia activation, propylene activation, oxygen activation, oxygen and nitrogen insertion, and deep oxidation. Therefore, acrylonitrile catalysts need bifunctional active centers: one for propylene molecule activation and the other for the chemisorption, activation, and insertion of oxygen and nitrogen. The de-α-H active center component is Bi. 3+ The nitrogen atom is inserted into the center as Mo. 6+ The redox component is Fe. 3+ / Fe 2+ Therefore, the chemical formula of the acrylonitrile catalyst in this application is X%[A] a B b C c D d Ni e Fe f Bi g Mo h O i ]+Y%SiO2, the acrylonitrile catalyst is a Mo-Bi-Fe system, due to Ce 3+ with Bi 3+ Particle radii are similar and Ce 4+ / Ce 3+ It also has the function of converting meteorological oxygen into lattice oxygen, Ce 4+ Transferring lattice oxygen and enabling Mo 4+ (Mo) 5+ ) converted to Mo 6+ Ce 4+ / Ce 3+ With α-Bi2Mo3O 12 Formation of Bi 2- x Ce x Mo3O 12The solid solution contains bifunctional active centers for acrylonitrile preparation and redox functions; therefore, Ce is the preferred carbon element, but lanthanide elements such as Pr or Nd can be substituted. To improve catalyst stability, D is added, including P, W, B, Cu, Sn, Ge, and Cr. To reduce the influence of Fe on the deep oxidation of olefins, A is used to replace some Fe, including Cr and Mn. To further stabilize the catalyst and improve its activity, B is typically added, including Mg, Zn, Ca, K, and Cs. To maintain high catalyst activity, the proportion of X can be appropriately increased, but it is generally not advisable to exceed 60%.

[0016] The beneficial effects of this invention are: Compared to existing technologies, which typically employ roasting regeneration methods, Fe2(MoO4)3 and α-Bi2Mo3O2 are involved in acrylonitrile production. 12 Deactivated into β-FeMoO4 and γ-Bi2O 3· MoO3 cannot be completely restored to the active component after calcination, and the elemental components of the active component are lost during the acrylonitrile generation process.

[0017] The advantage of this invention is that the raw material used is waste acrylonitrile catalyst, which turns waste into treasure, is environmentally friendly and pollution-free, and the composition of the regenerated catalyst is the same as that of the original catalyst, with comparable performance.

[0018] This invention recovers hydrofluoric acid for reuse during the regeneration of acrylonitrile catalyst, achieving the goals of environmental protection and cost savings.

[0019] Figure 1 This is a schematic diagram of the structure of an acrylonitrile catalyst regeneration preparation device according to the present invention.

[0020] Figure 2 This is one of the GC detection spectra of acrylonitrile after catalysis using the waste acrylonitrile catalyst regenerated in Example 1.

[0021] Figure 3 This is the second GC spectrum of acrylonitrile catalyzed using the waste acrylonitrile catalyst regenerated in Example 1.

[0022] Figure 4 This is one of the GC detection spectra of acrylonitrile after catalysis using the waste acrylonitrile catalyst regenerated in Example 2.

[0023] Figure 5 This is the second GC spectrum of acrylonitrile catalyzed using the waste acrylonitrile catalyst regenerated in Example 2.

[0024] In the diagram, 1 is an air jet mill; 2 is a reactor; 3 is an active ingredient replenishment tank; 4 is a hydrofluoric acid addition tank; 5 is a hydrofluoric acid absorption pump; 6 is a disperser; 7 is a circulation pump; 8 is a spray dryer; and 9 is a vibrating filter. Detailed Implementation

[0025] The present invention is further illustrated below with specific implementation examples. These examples are merely for more detailed and specific explanation and are not intended to limit the invention in any way. Those skilled in the art will understand that, unless otherwise specified below, the raw materials and operating methods used in the present invention are well known in the art.

[0026] Example 1

[0027] An apparatus for implementing a method for regenerating and preparing acrylonitrile catalyst includes a calcination system, a pulverization system, a reaction system, a detection system, a spray drying system, and a finished product calcination system; The roasting system and the finished product roasting system are roasting furnaces with oxygen introduction structures; The pulverizing system is an air jet mill 1, and the feed end of the air jet mill 1 is connected to the discharge end of the roasting furnace of the roasting system. The reaction system includes a reactor 2 with an external circulation pipeline, an active component replenishment tank 3, and a hydrofluoric acid addition tank 4. The active component replenishment tank 3 is equipped with a stirring device. Reactor 2 is equipped with a stirring device inside, a material feed inlet and a hydrofluoric acid feed inlet at the top, and a discharge outlet at the bottom; reactor 2 is also equipped with a nitric acid inlet and a sampling outlet. A disperser 6 is installed on the external circulation pipeline. The disperser 6 is connected to the reactor 2. A circulation pump 7 is installed between the disperser 6 and the reactor 2. The material inlet is connected to the active component replenishment tank 3, and the hydrofluoric acid inlet is connected to the hydrofluoric acid addition tank 4. This device has a hydrofluoric acid recovery function. A first hydrofluoric acid recovery pipeline and a second hydrofluoric acid recovery pipeline are also installed between the reactor 2 and the hydrofluoric acid addition tank 4. A shaking filter 9 is installed on the first hydrofluoric acid recovery pipeline. After the powdered material and hydrofluoric acid are fully contacted and reacted in the reaction system, the powdered material is filtered through the shaking filter 9 to obtain filtrate and filter residue. The filtrate is returned to the hydrofluoric acid addition tank 4 as hydrofluoric acid recovery. Hydrofluoric acid absorption pump 5 is installed on the second hydrofluoric acid recovery pipeline; the filter residue obtained by the vibrating filter 9 is heated to remove hydrofluoric acid, and the hydrofluoric acid removed from the filter residue is returned to the hydrofluoric acid addition tank 4 through the second hydrofluoric acid recovery pipeline. The spray drying system is a spray dryer 8, whose feed end is connected to the discharge end of the reactor 2. The spray dryer 8 is equipped with an inlet air temperature controller and an outlet air temperature controller.

[0028] In this application, the external circulation pipeline and the disperser 6 enable the waste acrylonitrile catalyst to fully contact and react with hydrofluoric acid to remove silica.

[0029] Example 2

[0030] After a 30-day stability test of the evaluation device, the acrylonitrile catalyst was discarded (original catalyst molecular formula: 50% [Cr]). 0.5 K 0.05 Cs 0.05 Mg 0.5 Ce 0.8 P 0.5 Ni6Fe2BiMo 12 O 50.25 The material (50% SiO2) was roasted in a roasting furnace at 600℃ for 8 hours, with oxygen continuously introduced during the roasting process. After roasting, it was pulverized using an air jet mill to obtain powdered material with a particle size of less than 800 mesh.

[0031] The powdered material and hydrofluoric acid are fed into reactor 2. The reactor 2 is equipped with a stirring device at a stirring rate of 100 r / min. The valve on the external circulation pipeline is opened, and the circulation pump 7 and disperser 6 are turned on to ensure complete reaction between the powdered material and hydrofluoric acid. The mass ratio of waste acrylonitrile catalyst to hydrofluoric acid is 1:5. The vibrating filter 9 is not turned on during this step.

[0032] After reacting for 8 hours, the shaking filter 9 is opened for filtration, yielding filtrate and filter residue. The filtrate is returned to the hydrofluoric acid addition tank 4 through the first hydrofluoric acid recovery pipeline.

[0033] The filter residue enters reactor 2, and reactor 2 is heated to remove hydrofluoric acid from the filter residue. The removed hydrofluoric acid is returned to the hydrofluoric acid addition tank 4 through hydrofluoric acid absorption pump 5 and the second hydrofluoric acid recovery pipeline.

[0034] Concentrated nitric acid is added through the nitric acid inlet on reactor 2, and the mixture is allowed to react and dissolve completely at 60°C to obtain a mixed nitrate salt. The pH is then adjusted to 2 using ammonia water to obtain a mixed solution.

[0035] Samples are taken from reactor 2, and the mixed solution sample is sent to the detection system to obtain the content of each component element, and the active components are supplemented by comparison with the predetermined formula.

[0036] The established formula is 50% [Cr] 0.5 K 0.05 Cs 0.05 Mg 0.5 Ce 0.8 P 0.5 Ni6Fe2BiMo 12 O 50.25 50% SiO2).

[0037] Active element replenishment amount = (target content percentage of a single element - current content percentage of a single element) × total mass of catalyst to be treated The amount of added active elements is then converted into active components in the form of nitrates or oxides.

[0038] Active components are added sequentially through active component replenishment tank 3 to fully dissolve in pure water. After thorough mixing in active component replenishment tank 3, the solution is added to reactor 2. The mixture is aged until the solid content reaches 45%. The 45% solid content mixed salt is then mixed with ammonia-stabilized silica sol containing a stabilizer to prepare a slurry. The slurry has a viscosity of 200 mPa·s, a solid content of 34%, and a specific gravity of 1.2 g / cm³. 3 .

[0039] The amount of stabilized ammonia-type silica sol containing stabilizers added is based on X% [A] a B b C c D d Ni e Fe f Bi g Mo h O i ]+Y%SiO2, X is 40, and X+Y=100.

[0040] The above slurry was dried in a spray dryer to form a solid powder with a moisture content of less than 0.5%. The inlet air temperature was controlled at 400℃ and the outlet temperature was controlled at 200℃. Particle size, moisture content and bulk density were tested. The qualified granules are roasted and shaped in a roasting furnace to obtain the regenerated catalyst product.

[0041] The regenerated catalyst product was loaded into a catalyst evaluation device for acrylonitrile synthesis, and the resulting materials were sampled and tested. GC testing yielded the following results: Figure 2 , Figure 3 As shown.

[0042] from Figure 2 As can be seen from the data: 3.110 min corresponds to the acrolein peak, 4.025 min corresponds to the butanone peak, 6.665 min corresponds to the acrylonitrile peak, 7.100 min corresponds to the acetonitrile peak, and 14.698 min corresponds to the acrylic acid peak. from Figure 3 As can be seen from the data: 2.738 min corresponds to the carbon dioxide peak, 9.444 min corresponds to the carbon monoxide peak, 21.567 min corresponds to the propylene peak, and 24.795 min corresponds to the propane peak. The calculated contents of each substance are as follows: acrylonitrile: 81.06%, hydrogen cyanide: 3.5%, acetonitrile: 2.27%, acrylic acid: 0.48%, acrolein: 0.78%, carbon monoxide: 5.05%, carbon dioxide: 6.66%, propylene: 0.16%, propane: 0.04%, that is, the total conversion rate of propylene is 99.84%.

[0043] The previously unused catalyst product was loaded into a catalyst evaluation device for acrylonitrile synthesis, and the generated materials were sampled and tested. GC analysis revealed the following content of each substance: acrylonitrile: 81.96%, hydrogen cyanide: 3.3%, acetonitrile: 2.07%, acrylic acid: 0.28%, acrolein: 0.58%, carbon monoxide: 4.85%, carbon dioxide: 6.66%, propylene: 0.29%, propane: 0.01%, resulting in a total propylene conversion rate of 99.71%.

[0044] The regenerated acrylonitrile catalyst prepared by the method of this invention achieves the activity of a normal acrylonitrile catalyst.

[0045] Example 3

[0046] After a 30-day stability test of the evaluation device, the acrylonitrile catalyst was discarded (original catalyst molecular formula: 50% [Cr]). 0.5 K 0.05 Cs 0.05 Mg 0.5 Ce 0.8 P 0.5 Ni6Fe2BiMo 12 O 50.1 The material (50% SiO2) was roasted in a roasting furnace at 650°C for 4 hours, with oxygen continuously introduced during the roasting process. After roasting, it was pulverized using an air jet mill to obtain a powdery material with a particle size of less than 800 mesh.

[0047] The powdered material and hydrofluoric acid are fed into reactor 2. The reactor 2 is equipped with a stirring device at a stirring rate of 300 r / min. The valve on the external circulation pipeline is opened, and the circulation pump 7 and disperser 6 are turned on to ensure complete reaction between the powdered material and hydrofluoric acid. The mass ratio of waste acrylonitrile catalyst to hydrofluoric acid is 1:5.

[0048] After reacting for 16 hours, the shaking filter 9 was opened for filtration, yielding filtrate and filter residue. The filtrate was returned to the hydrofluoric acid addition tank 4 through the first hydrofluoric acid recovery pipeline.

[0049] The reactor 2 is heated to remove hydrofluoric acid from the filter residue. The removed hydrofluoric acid is returned to the hydrofluoric acid addition tank 4 through the hydrofluoric acid absorption pump 5 and the second hydrofluoric acid recovery pipeline.

[0050] Concentrated nitric acid is added through the nitric acid inlet on reactor 2, and the mixture is fully reacted and dissolved at 60°C to obtain a mixed nitrate salt. The pH is then adjusted to 2 using ammonia water to obtain a mixed solution.

[0051] Sampling is performed, and the mixed solution sample is sent into the detection system to obtain the content of each component element. The active components are then supplemented and compared with the predetermined formula.

[0052] Active element replenishment amount = (target content percentage of a single element - current content percentage of a single element) × total mass of catalyst to be treated The amount of added active elements is then converted into active components in the form of nitrates or oxides.

[0053] Potassium nitrate, cesium nitrate, magnesium nitrate, cerium nitrate, praseodymium nitrate, manganese nitrate, nickel nitrate, ferric nitrate, and bismuth nitrate are added sequentially to active component replenishment tank 3, ensuring complete dissolution in pure water. After thorough mixing in active component replenishment tank 3, the solution is added to reactor 2. The mixture is aged until the solid content reaches 65%. A slurry is prepared by mixing the 65% solid content mixed salt with a stabilized ammonia-type silica sol containing a stabilizer. The slurry has a viscosity of 400 mPa·s, a solid content of 45%, and a specific gravity of 1.5 g / cm³. 3 .

[0054] The amount of stabilized ammonia-type silica sol containing stabilizers added is calculated according to the following ratio: 50% [Cr] 0.5 K 0.05 Cs 0.05 Mg 0.5 Ce 0.8 P 0.5 Ni6Fe2BiMo 12 O 50.1 50% SiO2, X is 60, and X+Y=100.

[0055] The above slurry was dried in a spray dryer to form a solid powder with a moisture content of less than 0.5%. The inlet air temperature was controlled at 400℃ and the outlet temperature was controlled at 200℃. Particle size, moisture content and bulk density were tested. Particle size distribution: <44μm: 10-25%; 44-88μm: 40-60%; >88μm: <5%; Moisture content less than 0.5%; Loose density: 0.8-1.2 g / cm³ 3 .

[0056] After passing the inspection, the catalyst is roasted and shaped in a roasting furnace to obtain the regenerated catalyst product.

[0057] The regenerated catalyst product was loaded into a catalyst evaluation device for acrylonitrile synthesis, and the resulting materials were sampled and tested. GC testing yielded the following results: Figure 4 , Figure 5 As shown.

[0058] from Figure 4 It can be seen that: the peak at time 3.110 min corresponds to acrolein, the peak at 4.025 min corresponds to methyl ethyl ketone, the peak at 6.665 min corresponds to acrylonitrile, the peak at 7.104 min corresponds to acetonitrile, and the peak at 14.698 min corresponds to acrylic acid. from Figure 5 It can be seen that the peak at 2.741 min corresponds to carbon dioxide, the peak at 9.500 min corresponds to carbon monoxide, the peak at 21.569 min corresponds to propylene, and the peak at 24.798 min corresponds to propane.

[0059] The calculated contents of each substance are as follows: acrylonitrile: 82.15%, hydrogen cyanide: 3.11%, acetonitrile: 1.07%, acrylic acid: 1.28%, acrolein: 1.58%, carbon monoxide: 4.35%, carbon dioxide: 6.16%, propylene: 0.25%, propane: 0.05%, that is, the total conversion rate of propylene is 99.75%.

[0060] The previously unused catalyst product was loaded into a catalyst evaluation device for acrylonitrile synthesis, and the generated materials were sampled and tested. GC analysis revealed the following content of each substance: acrylonitrile: 82.0%, hydrogen cyanide: 3.4%, acetonitrile: 2.17%, acrylic acid: 0.74%, acrolein: 0.78%, carbon monoxide: 3.55%, carbon dioxide: 6.06%, propylene: 0.26%, propane: 0.04%, resulting in a total propylene conversion rate of 99.74%.

[0061] The regenerated acrylonitrile catalyst prepared by the method of this invention achieves the activity of a normal acrylonitrile catalyst.

Claims

1. A method for regenerating and preparing an acrylonitrile catalyst, characterized in that, Includes the following steps: ① The waste acrylonitrile catalyst is fed into the roasting system for roasting. After roasting, it is processed by the pulverizing system to obtain powdered material with a particle size of less than 800 mesh. ② The powdered material and hydrofluoric acid are fed into the reaction system. After the powdered material and hydrofluoric acid react fully in the reaction system, the mixture is filtered to obtain filtrate and filter residue. The filtrate is recovered as hydrofluoric acid, and the filter residue is heated to remove hydrofluoric acid to obtain solid material. The hydrofluoric acid removed from the filter residue is recovered. ③ Dissolve the solid material in nitric acid to obtain a mixed nitrate salt. Adjust the pH of the mixed nitrate salt to 2 to obtain a mixed solution. ④ Take a sample from the mixed solution, send the sample into the detection system to obtain the detection result, and compare the detection result with A. a B b C c D d Ni e Fe f Bi g Mo h O i The amount of missing active components was compared and calculated, and the corresponding missing active components were added to the mixed solution. The solution was then aged until the solid content of the mixed salt was 45%–65%. ⑤ A slurry is prepared by mixing a mixed salt with a solid content of 45%-65% with an ammonia-stabilized silica sol containing a stabilizer, wherein the stabilizer is an ammonia-ammonium chloride buffer solution; ⑥ The slurry is fed into a spray drying system, and the inlet air temperature is controlled at 350-400℃ and the outlet air temperature is controlled at 150-200℃. After spray drying, a solid powder with a water content of less than 0.5% is formed. ⑦ The solid powder is fed into a finished product roasting system for roasting, and after roasting, a product with the chemical formula X%[A] is obtained. a B b C c D d Ni e Fe f Bi g Mo h O i Acrylonitrile catalyst with ]+Y%SiO2; Wherein, A is selected from at least one of Cr and Mn, B is selected from at least one of Mg, Zn, Ca, K, and Cs, C is selected from at least one of Ce, Pr, and Nd, and D is selected from at least one of P, W, B, Cu, Sn, Ge, and Cr; a is 0.03–0.5, b is 0.5–5, c is 0.1–1.1, d is 0.1–0.9, e is 1–10, f is 1–5, g is 0.1–1, h is 8–16, and i is the number of oxygen atoms required to satisfy the oxidation states of each element in the chemical formula; X is between 40 and 60, and X + Y = 100.

2. The method for regenerating and preparing acrylonitrile catalyst according to claim 1, characterized in that, The slurry mentioned in step ⑤ has a viscosity of 200-400 mPa·s, a solid content of 34-45%, and a specific gravity of 1.2-1.5 g / cm³. 3 .

3. The method for regenerating and preparing acrylonitrile catalyst according to claim 1, characterized in that, The roasting temperature in steps ① and ⑦ is 600-650℃, the roasting time is 4-8 hours, and oxygen is continuously introduced during the roasting process.

4. The method for regenerating and preparing acrylonitrile catalyst according to claim 1, characterized in that, The reaction time between the powdered material and hydrofluoric acid in step ② is 8-16 hours within the reaction system.

5. The method for regenerating and preparing acrylonitrile catalyst according to claim 1, characterized in that, Step 4: Replenish the mixed solution with the missing active component, which is in the form of nitrate or oxide.

6. The method for regenerating and preparing acrylonitrile catalyst according to claim 1, characterized in that, The mass ratio of the waste acrylonitrile catalyst to the hydrofluoric acid is 1:

5.

7. An apparatus for implementing the acrylonitrile catalyst regeneration preparation method according to claim 1, characterized in that, It includes a roasting system, a pulverizing system, a reaction system, a detection system, a spray drying system, and a finished product roasting system; The roasting system and the finished product roasting system are roasting furnaces with oxygen introduction structures; The pulverizing system is an air jet mill, and the feed end of the air jet mill is connected to the discharge end of the roasting furnace of the roasting system. The reaction system includes a reactor with an external circulation pipeline, an active component replenishment tank, and a hydrofluoric acid addition tank. The reactor is equipped with a stirring device, a material inlet and a hydrofluoric acid inlet at the top, and a discharge outlet at the bottom. A disperser is installed on the external circulation pipeline. The material inlet is connected to the active component replenishment tank, and the hydrofluoric acid inlet is connected to the hydrofluoric acid addition tank. A first hydrofluoric acid recovery pipeline and a second hydrofluoric acid recovery pipeline are also installed between the reactor and the hydrofluoric acid addition tank. A vibrating filter is installed on the first hydrofluoric acid recovery pipeline, and a hydrofluoric acid absorption pump is installed on the second hydrofluoric acid recovery pipeline. The spray drying system is a spray dryer, whose feed end is connected to the discharge end of the reactor. The spray dryer is equipped with an inlet air temperature controller and an outlet air temperature controller.

8. The apparatus for the acrylonitrile catalyst regeneration preparation method according to claim 7, characterized in that, The detection system is an ICP detection system.

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