Method for testing stability of pyridine catalyst and screening method

Abstract

The invention relates to the field of catalyst testing, and particularly provides a pyridine catalyst stability testing method and a screening method. The pyridine catalyst stability test method comprises the following steps: S1, placing a pyridine catalyst in a fluidized bed reactor; s2, feeding water by using a feeding pump, vaporizing the water, contacting the vaporized water with the pyridine catalyst, taking the contact time of water vapor and the pyridine catalyst as a time starting point, carrying out water treatment for 10-60 hours, and then removing the pyridine catalyst subjected to hydro-thermal treatment; s3, the pyridine catalyst subjected to hydro-thermal treatment is placed in another fluidized bed reactor for a reaction, formaldehyde and acetaldehyde are fed, and ammonia gas is introduced at the same time; and S4, sampling once every set time interval, recording the weight of the fed material and the weight of the discharged material, and calculating the yield. The test period is short, and the required catalyst can be effectively screened out.

Description

Technical Field

[0001] The present invention relates to the field of catalyst testing, and in particular, to a method for testing the stability and a screening method of a pyridine catalyst. Background Art

[0002] Molecular sieve catalysts are widely used in the process of aldehyde-ammonia condensation to produce pyridine. However, the service life of the catalyst is relatively short. As the industrial device operates, the activity of the molecular sieve catalyst will rapidly decline due to carbon deposition, and the yield of pyridine will significantly decrease. Thermal stability and hydrothermal stability are important indicators to measure the performance of the catalyst. And since the fresh catalyst has not experienced the reaction process, the initial activity is not representative. Therefore, it is very necessary to study the stability of the shaped catalyst by studying the hydrothermal treatment conditions.

[0003] To simulate the attenuation of catalyst activity in the industrial process, the catalyst is usually pre-hydrothermally treated under highly severe conditions. The catalyst is fluidized with air at 500 - 800 °C. Under the conditions of high temperature and water vapor, the physicochemical properties and catalytic properties of the molecular sieve catalyst change, so that the catalyst reaches the equilibrium activity. In the prior art, the pyridine catalyst hydrothermal treatment device and the fluidized bed reactor are usually a set of devices, which has the disadvantage of a long reaction cycle. Therefore, how to use a simple method to measure the stability of the pyridine catalyst, shorten the reaction cycle, and quickly obtain the stable performance of the pyridine catalyst is a problem that the industry hopes to solve.

[0004] In view of this, the present invention is specifically proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for testing the stability and a screening method of a pyridine catalyst to solve the problems of the long testing cycle of the pyridine catalyst stability and the difficulty in catalyst screening existing in the prior art.

[0006] In order to achieve the above object of the present invention, the following technical solutions are specifically adopted:

[0007] In a first aspect, the present invention provides a method for testing the stability of a pyridine catalyst, including:

[0008] S1. Place the pyridine catalyst in a fluidized bed reactor;

[0009] S2: Feed water with a feed pump. After the water is vaporized, it contacts the pyridine catalyst. Starting from the contact time of the water vapor with the pyridine catalyst as the time starting point, conduct water treatment for 10 - 60 h, and then remove the pyridine catalyst after hydrothermal treatment;

[0010] S3. Place the pyridine catalyst after hydrothermal treatment in another fluidized bed reactor for reaction, with the feed being formaldehyde and acetaldehyde, and simultaneously introduce ammonia;

[0011] S4. Sample once every set time interval, record the weights of the feed and the product discharge, and calculate the yield.

[0012] As a further preferred technical solution, the temperature in the fluidized bed reactor in S1 is 500 - 800 °C.

[0013] As a further preferred technical solution, in S1, after placing the pyridine catalyst in the fluidized bed reactor, it further includes the step of introducing air or nitrogen at a flow rate of 1 - 5 L / min.

[0014] As a further preferred technical solution, the water inlet flow rate in S2 is 2 - 8 mL / min.

[0015] As a further preferred technical solution, the temperature in the other fluidized bed reactor in S3 is 350 - 500 °C.

[0016] As a further preferred technical solution, the feed flow rate in S3 is 2 - 10 mL / min.

[0017] As a further preferred technical solution, the ammonia flow rate in S3 is 1 - 5 L / min.

[0018] In a second aspect, the present invention provides a method for screening pyridine catalysts, including:

[0019] Testing the pyridine catalyst using the above pyridine catalyst stability test method, with the water treatment times being 30 h and 60 h respectively;

[0020] Based on the test results, determine whether the pyridine catalyst is a non - qualified catalyst, a qualified catalyst, or an excellent - quality catalyst.

[0021] As a further preferred technical solution, the step of determining whether the pyridine catalyst is a non - qualified catalyst, a qualified catalyst, or an excellent - quality catalyst based on the test results includes:

[0022] If, after testing at a water treatment time of 30 h, the yield decline rate is greater than the first preset rate, then determine that the pyridine catalyst is a non - qualified catalyst;

[0023] If, after testing at a water treatment time of 30 h, the yield does not decline or the decline rate is within the first preset rate, and after testing at a water treatment time of 60 h, the yield decline rate is greater than the second preset rate, then determine that the pyridine catalyst is a qualified catalyst;

[0024] If, after testing at a water treatment time of 60 h, the yield decline rate is within the second preset rate, then determine that the pyridine catalyst is an excellent - quality catalyst.

[0025] As a further preferred technical solution,

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] In the method for testing the stability of the pyridine catalyst provided by the present invention, the pyridine catalyst is first placed in a fluidized bed reactor for water-destructive treatment, and then another fluidized bed reactor is used to evaluate the performance of the treated catalyst, so that the hydrothermal stability of the pyridine catalyst can be quickly verified, and the test period is short.

[0028] The method for screening the pyridine catalyst provided by the present invention adopts the above method for testing the stability of the pyridine catalyst, the difference being that the water treatment times are 30 h and 60 h respectively, and then based on the test results, it is determined whether the pyridine catalyst is a non-conforming catalyst, a qualified catalyst or an excellent-quality catalyst. This method can effectively screen out the required catalyst. Detailed implementation mode

[0029] The following will describe the implementation scheme of the present invention in detail in conjunction with the embodiments. However, those skilled in the art will understand that the following embodiments are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. Those not specified in the embodiments are carried out under conventional conditions or conditions recommended by the manufacturer.

[0030] As one aspect of the present invention, the present invention provides a method for testing the stability of a pyridine catalyst, including:

[0031] S1. Place the pyridine catalyst in a fluidized bed reactor;

[0032] S2: Feed water with a feed pump. After the water is vaporized, it contacts the pyridine catalyst. Starting from the contact time of the water vapor with the pyridine catalyst as the time starting point, carry out water treatment for 10 - 60 h, and then remove the pyridine catalyst after the hydrothermal treatment;

[0033] S3. Place the pyridine catalyst after the hydrothermal treatment in another fluidized bed reactor for reaction, with the feed being formaldehyde and acetaldehyde, and ammonia gas being introduced simultaneously;

[0034] S4. Take samples at regular time intervals, record the weights of the feed and the product, and calculate the yield.

[0035] Among them, a fluidized bed reactor is a reactor that uses a gas or liquid to pass through a granular solid layer to make the solid particles in a suspended motion state and carry out a gas-solid phase reaction process or a liquid-solid phase reaction process. When used in a gas-solid system, it is also called a fluidized bed reactor. Optionally, the fluidized bed reactor is composed of a preheater, a reactor, a condenser, a raw material tank, a receiving tank, an ammonia flowmeter, an ammonia flowmeter, a refrigerator, a feed pump, etc.

[0036] A pyridine catalyst refers to a catalyst that catalyzes the aldol condensation reaction of formaldehyde, acetaldehyde, and ammonia to produce pyridine bases.

[0037] The yield refers to the ratio of the mass of the target product (pyridine base) formed in the reaction per unit time to the mass of the raw materials (formaldehyde and acetaldehyde) fed.

[0038]

[0039] Optionally, in step S2, water is vaporized after being preheated by a preheater.

[0040] Optionally, in step S3, formaldehyde and acetaldehyde are placed in a raw material tank in advance. Among them, the weight ratio of formaldehyde and acetaldehyde can adopt the ratio that can achieve the synthesis purpose in the prior art, and the present invention does not make special restrictions on this.

[0041] Optionally, the above set time interval is, for example, 1 hour or 2 hours.

[0042] Optionally, an Agilent 7820 gas chromatograph TCD detector is used for analysis.

[0043] Optionally, the cooling temperature of the absorption tank of the fluidized bed reactor in step S3 is stabilized at -5°C.

[0044] Optionally, in step S3, before introducing ammonia, the fluidized bed system is purged with nitrogen.

[0045] In an alternative embodiment, the temperature in the fluidized bed reactor in S1 is 500 - 800°C. The above temperature includes but is not limited to 500°C, 520°C, 540°C, 560°C, 580°C, 600°C, 620°C, 640°C, 680°C, 700°C, 720°C, 740°C, 760°C, 780°C, or 800°C. The higher the temperature, the more serious the damage to the catalyst, and the more the stable performance of the catalyst can be reflected.

[0046] In an alternative embodiment, in S1, after placing the pyridine catalyst in the fluidized bed reactor, it further includes a step of introducing air or nitrogen at a flow rate of 1 - 5 L / min. The above flow rate of air or nitrogen includes but is not limited to 1 L / min, 2 L / min, 3 L / min, 4 L / min, or 5 L / min.

[0047] In an alternative embodiment, the water inlet flow rate in S2 is 2 - 8 mL / min. The above water flow rate includes but is not limited to 2 mL / min, 3 mL / min, 4 mL / min, 5 mL / min, 6 mL / min, 7 mL / min, or 8 mL / min. The more water is introduced, the greater the damage to the catalyst. If the catalyst can still maintain a good yield, it indicates that the catalyst is of excellent quality.

[0048] In an alternative embodiment, the temperature in the other fluidized bed reactor in S3 is 350 - 500 °C. The above temperature includes but is not limited to 350 °C, 360 °C, 370 °C, 380 °C, 390 °C, 400 °C, 410 °C, 420 °C, 430 °C, 440 °C, 450 °C, 460 °C, 470 °C, 480 °C, 490 °C or 500 °C. The reaction of catalytic synthesis of pyridine bases from formaldehyde and acetaldehyde is an endothermic reaction. With the increase of reaction temperature, the yield of pyridine bases will increase to a certain extent; if the temperature continues to increase, the yield of pyridine bases will decrease instead, because too high temperature will lead to the formation of high-boiling substances and the increase of carbon deposition on the catalyst, thus reducing the catalytic performance of the catalyst. When the reaction temperature is the above temperature, especially 450 °C, it is more suitable for the formation of pyridine.

[0049] In an alternative embodiment, the feed flow rate in S3 is 2 - 10 mL / min. The above feed flow rate includes but is not limited to 2 L / min, 3 L / min, 4 L / min, 5 L / min, 6 L / min, 7 L / min, 8 L / min, 9 L / min or 10 L / min.

[0050] In an alternative embodiment, the ammonia flow rate in S3 is 1 - 5 L / min. The above ammonia flow rate includes but is not limited to 1 L / min, 2 L / min, 3 L / min, 4 L / min or 5 L / min.

[0051] Optionally, after reacting for 6 - 8 h in S3, stop the reaction, remove the pyridine catalyst, and then regenerate the catalyst with a muffle furnace.

[0052] Optionally, the regeneration temperature is 400 - 600 °C, and the calcination time is 2 - 8 h.

[0053] The above method for testing the stability of the pyridine catalyst first places the pyridine catalyst in a fluidized bed reactor for water-passing destructive treatment, and then uses another fluidized bed reactor to conduct performance evaluation and analysis on the treated catalyst, so that the hydrothermal stability of the pyridine catalyst can be quickly verified, and the test period is short.

[0054] As another aspect of the present invention, the present invention provides a method for screening pyridine catalysts, including:

[0055] Testing the pyridine catalyst by using the above method for testing the stability of the pyridine catalyst, and the water-passing treatment times are 30 h and 60 h respectively;

[0056] According to the test results, determine whether the pyridine catalyst is a non-conforming catalyst, a qualified catalyst or an excellent-quality catalyst.

[0057] This method for screening pyridine catalysts uses the above-mentioned method for testing the stability of pyridine catalysts, with the difference that the water treatment times are 30 h and 60 h respectively. Then, based on the test results, it is determined whether the pyridine catalyst is a substandard catalyst, a qualified catalyst, or an excellent-quality catalyst. This method can effectively screen out the required catalysts.

[0058] In an alternative embodiment, determining whether the pyridine catalyst is a substandard catalyst, a qualified catalyst, or an excellent-quality catalyst based on the test results includes:

[0059] If the yield decline rate is greater than the first preset rate after testing under a water treatment time of 30 h, it is determined that the pyridine catalyst is a substandard catalyst;

[0060] If the yield does not decline or the decline rate is within the first preset rate after testing under a water treatment time of 30 h, and the yield decline rate is greater than the second preset rate after testing under a water treatment time of 60 h, it is determined that the pyridine catalyst is a qualified catalyst;

[0061] If the yield decline rate is within the second preset rate after testing under a water treatment time of 60 h, it is determined that the pyridine catalyst is an excellent-quality catalyst.

[0062] Among them, both the first preset rate and the second preset rate are relatively small rate values, such as 1% - 5%. At this rate range, it indicates that the performance of the catalyst does not decline significantly.

[0063] The present invention will be further described in detail below with reference to examples and comparative examples.

[0064] Example 1:

[0065] Hydrothermal treatment: Charge 200 g of pyridine catalyst A into a fluidized bed at 600 °C, introduce air at 2 L / min, and introduce pure water at 6 mL / min through a feed pump into the fluidized bed after passing through a preheater. Start timing from the moment the water vapor enters the fluidized bed and contacts the catalyst. Stop water injection after 10 h of water injection, blow for 10 min, and then stop the air and remove the catalyst.

[0066] Reaction: Load the pyridine catalyst that has undergone 10 h of hydrothermal treatment and removed into a fluidized bed reactor at 450 °C. The raw material is a mixture of methyl ethyl aldehydes, the feed rate is 2 mL / min, introduce ammonia at 3 L / min, sample once per hour and analyze the product content by gas chromatography. At the same time, record the weights of the raw material and the product to calculate the yield.

[0067] Example 2:

[0068] Hydrothermal treatment: Charge 200 g of pyridine catalyst A into a fluidized bed at 600 °C, introduce air at 2 L / min, and feed 6 mL / min of pure water through a feed pump into the fluidized bed via a preheater. Start timing from when the steam enters the fluidized bed and contacts the catalyst. Stop water feeding after 20 h of water passing, blow for 10 min, and then stop the air and remove the catalyst.

[0069] Reaction: Load the pyridine catalyst that has undergone 20 h of hydrothermal treatment and has been removed into a fluidized bed reactor at 450 °C. The raw material is a mixture of methyl ethyl aldehydes, the feeding rate is 2 mL / min, introduce ammonia at 3 L / min, take samples once an hour and analyze the product content by gas chromatography. At the same time, record the weights of the raw material and the discharged material to calculate the yield.

[0070] Example 3:

[0071] Hydrothermal treatment: Charge 200 g of pyridine catalyst A into a fluidized bed at 600 °C, introduce air at 2 L / min, and feed 6 mL / min of pure water through a feed pump into the fluidized bed via a preheater. Start timing from when the steam enters the fluidized bed and contacts the catalyst. Stop water feeding after 30 h of water passing, blow for 10 min, and then stop the air and remove the catalyst.

[0072] Reaction: Load the pyridine catalyst that has undergone 30 h of hydrothermal treatment and has been removed into a fluidized bed reactor at 450 °C. The raw material is a mixture of methyl ethyl aldehydes, the feeding rate is 2 mL / min, introduce ammonia at 3 L / min, take samples once an hour and analyze the product content by gas chromatography. At the same time, record the weights of the raw material and the discharged material to calculate the yield.

[0073] Example 4:

[0074] Hydrothermal treatment: Charge 200 g of pyridine catalyst A into a fluidized bed at 600 °C, introduce air at 2 L / min, and feed 8 mL / min of pure water through a feed pump into the fluidized bed via a preheater. Start timing from when the steam enters the fluidized bed and contacts the catalyst. Stop water feeding after 60 h of water passing, blow for 10 min, and then stop the air and remove the catalyst.

[0075] Reaction: Load the pyridine catalyst that has undergone 60 h of hydrothermal treatment and has been removed into a fluidized bed reactor at 450 °C. The raw material is a mixture of methyl ethyl aldehydes, the feeding rate is 2 mL / min, introduce ammonia at 3 L / min, take samples once an hour and analyze the product content by gas chromatography. At the same time, record the weights of the raw material and the discharged material to calculate the yield.

[0076] Example 5:

[0077] Hydrothermal treatment: Charge 200 g of pyridine catalyst A into a fluidized bed at 600 °C, introduce air at 2 L / min, and feed 8 mL / min of pure water through a feed pump into the fluidized bed via a preheater. Start timing from when the steam enters the fluidized bed and contacts the catalyst. Stop water feeding after 10 h of water passing, blow for 10 min, and then stop the air and remove the catalyst.

[0078] Reaction: Load the pyridine catalyst that has been hydrothermally treated for 10 h and removed into a fluidized bed reactor at 450 °C. The raw materials are a mixture of methyl ethyl aldehyde, with a feed rate of 2 mL / min, ammonia is fed at 3 L / min, samples are taken once per hour and the product content is analyzed by gas chromatography. At the same time, the weights of the raw materials and the discharged materials are also recorded to calculate the yield.

[0079] Example 6:

[0080] Hydrothermal treatment: Load 200 g of pyridine catalyst A into a fluidized bed at 600 °C, feed air at 2 L / min, and the feed pump feeds pure water at 8 mL / min into the fluidized bed through a preheater. Starting from the time when water vapor enters the fluidized bed and contacts the catalyst, stop water feeding after 20 h of water injection, stop air after blowing for 10 min, and then remove the catalyst.

[0081] Reaction: Load the pyridine catalyst that has been hydrothermally treated for 20 h and removed into a fluidized bed reactor at 450 °C. The raw materials are a mixture of methyl ethyl aldehyde, with a feed rate of 2 mL / min, ammonia is fed at 3 L / min, samples are taken once per hour and the product content is analyzed by gas chromatography. At the same time, the weights of the raw materials and the discharged materials are also recorded to calculate the yield.

[0082] Example 7:

[0083] Hydrothermal treatment: Load 200 g of pyridine catalyst A into a fluidized bed at 600 °C, feed air at 2 L / min, and the feed pump feeds pure water at 8 mL / min into the fluidized bed through a preheater. Starting from the time when water vapor enters the fluidized bed and contacts the catalyst, stop water feeding after 30 h of water injection, stop air after blowing for 10 min, and then remove the catalyst.

[0084] Reaction: Load the pyridine catalyst that has been hydrothermally treated for 30 h and removed into a fluidized bed reactor at 450 °C. The raw materials are a mixture of methyl ethyl aldehyde, with a feed rate of 2 mL / min, ammonia is fed at 3 L / min, samples are taken once per hour and the product content is analyzed by gas chromatography. At the same time, the weights of the raw materials and the discharged materials are also recorded to calculate the yield.

[0085] Example 8:

[0086] Hydrothermal treatment: Load 200 g of pyridine catalyst A into a fluidized bed at 600 °C, feed air at 2 L / min, and the feed pump feeds pure water at 8 mL / min into the fluidized bed through a preheater. Starting from the time when water vapor enters the fluidized bed and contacts the catalyst, stop water feeding after 60 h of water injection, stop air after blowing for 10 min, and then remove the catalyst.

[0087] Reaction: The removed pyridine catalyst that has been hydrothermally treated for 60 h is loaded into a fluidized bed reactor at 450 °C. The raw materials are a mixture of methyl ethyl aldehydes, with a feed rate of 2 mL / min, 3 L / min of ammonia is introduced. Samples are taken once an hour and the product content is analyzed by gas chromatography. At the same time, the weights of the raw materials and the discharged materials are also recorded to calculate the yield.

[0088] Example 9:

[0089] Hydrothermal treatment: 200 g of pyridine catalyst A is loaded into a fluidized bed at 800 °C, 2 L / min of air is introduced, and 8 mL / min of pure water is fed into the fluidized bed through a feed pump and enters through a preheater. Starting from the time when water vapor enters the fluidized bed and contacts the catalyst, water feeding is stopped after 10 h of water passing, and air is stopped after blowing for 10 min, then the catalyst is removed.

[0090] Reaction: The removed pyridine catalyst that has been hydrothermally treated for 10 h is loaded into a fluidized bed reactor at 450 °C. The raw materials are a mixture of methyl ethyl aldehydes, with a feed rate of 2 mL / min, 3 L / min of ammonia is introduced. Samples are taken once an hour and the product content is analyzed by gas chromatography. At the same time, the weights of the raw materials and the discharged materials are also recorded to calculate the yield.

[0091] Example 10:

[0092] Hydrothermal treatment: 200 g of pyridine catalyst A is loaded into a fluidized bed at 800 °C, 2 L / min of air is introduced, and 8 mL / min of pure water is fed into the fluidized bed through a feed pump and enters through a preheater. Starting from the time when water vapor enters the fluidized bed and contacts the catalyst, water feeding is stopped after 20 h of water passing, and air is stopped after blowing for 10 min, then the catalyst is removed.

[0093] Reaction: The removed pyridine catalyst that has been hydrothermally treated for 20 h is loaded into a fluidized bed reactor at 450 °C. The raw materials are a mixture of methyl ethyl aldehydes, with a feed rate of 2 mL / min, 3 L / min of ammonia is introduced. Samples are taken once an hour and the product content is analyzed by gas chromatography. At the same time, the weights of the raw materials and the discharged materials are also recorded to calculate the yield.

[0094] Example 11:

[0095] Hydrothermal treatment: 200 g of pyridine catalyst A is loaded into a fluidized bed at 800 °C, 2 L / min of air is introduced, and 8 mL / min of pure water is fed into the fluidized bed through a feed pump and enters through a preheater. Starting from the time when water vapor enters the fluidized bed and contacts the catalyst, water feeding is stopped after 30 h of water passing, and air is stopped after blowing for 10 min, then the catalyst is removed.

[0096] Reaction: The removed pyridine catalyst that has been hydrothermally treated for 30 h is loaded into a fluidized bed reactor at 450 °C. The raw materials are a mixture of methyl ethyl aldehydes, with a feed rate of 2 mL / min, 3 L / min of ammonia is introduced. Samples are taken once an hour and the product content is analyzed by gas chromatography. At the same time, the weights of the raw materials and the discharged materials are also recorded to calculate the yield.

[0097] Example 12:

[0098] Hydrothermal treatment: Charge 200 g of pyridine catalyst A into an 800 °C fluidized bed, introduce air at 2 L / min, and feed 8 mL / min of pure water through a feed pump into the fluidized bed via a preheater. Start timing from when the steam enters the fluidized bed and contacts the catalyst. Stop water feeding after 60 h of water passing, blow for 10 min, and then stop the air and remove the catalyst.

[0099] Reaction: Load the removed pyridine catalyst that has undergone hydrothermal treatment for 60 h into a 450 °C fluidized bed reactor. The raw material is a mixture of methyl ethyl aldehyde, the feeding rate is 2 mL / min, introduce ammonia at 3 L / min, take samples once per hour and analyze the product content by gas chromatography. At the same time, record the weights of the raw material and the discharged material to calculate the yield.

[0100] Example 13:

[0101] Hydrothermal treatment: Charge 200 g of pyridine catalyst B into a 600 °C fluidized bed, introduce air at 2 L / min, and feed 6 mL / min of pure water through a feed pump into the fluidized bed via a preheater. Start timing from when the steam enters the fluidized bed and contacts the catalyst. Stop water feeding after 10 h of water passing, blow for 10 min, and then stop the air and remove the catalyst.

[0102] Reaction: Load the removed pyridine catalyst that has undergone hydrothermal treatment for 10 h into a 450 °C fluidized bed reactor. The raw material is a mixture of methyl ethyl aldehyde, the feeding rate is 2 mL / min, introduce ammonia at 3 L / min, take samples once per hour and analyze the product content by gas chromatography. At the same time, record the weights of the raw material and the discharged material to calculate the yield.

[0103] Example 14:

[0104] Hydrothermal treatment: Charge 200 g of pyridine catalyst B into a 600 °C fluidized bed, introduce air at 2 L / min, and feed 6 mL / min of pure water through a feed pump into the fluidized bed via a preheater. Start timing from when the steam enters the fluidized bed and contacts the catalyst. Stop water feeding after 20 h of water passing, blow for 10 min, and then stop the air and remove the catalyst.

[0105] Reaction: Load the removed pyridine catalyst that has undergone hydrothermal treatment for 20 h into a 450 °C fluidized bed reactor. The raw material is a mixture of methyl ethyl aldehyde, the feeding rate is 2 mL / min, introduce ammonia at 3 L / min, take samples once per hour and analyze the product content by gas chromatography. At the same time, record the weights of the raw material and the discharged material to calculate the yield.

[0106] Example 15:

[0107] Hydrothermal treatment: Charge 200 g of pyridine catalyst B into a fluidized bed at 600 °C. Feed air at 2 L / min and feed pure water at 6 mL / min through a feed pump into the fluidized bed via a preheater. Start timing from when the steam enters the fluidized bed and contacts the catalyst. Stop water feeding after 30 h of water flow, blow for 10 min, then stop air and remove the catalyst.

[0108] Reaction: Load the pyridine catalyst that has undergone 30 h of hydrothermal treatment and been removed into a fluidized bed reactor at 450 °C. The raw material is a mixture of methyl ethyl aldehyde, with a feed rate of 2 mL / min. Feed ammonia at 3 L / min. Take samples once an hour and analyze the product content by gas chromatography. At the same time, record the weights of the raw material and the discharged material to calculate the yield.

[0109] Example 16:

[0110] Hydrothermal treatment: Charge 200 g of pyridine catalyst B into a fluidized bed at 600 °C. Feed air at 2 L / min and feed pure water at 6 mL / min through a feed pump into the fluidized bed via a preheater. Start timing from when the steam enters the fluidized bed and contacts the catalyst. Stop water feeding after 60 h of water flow, blow for 10 min, then stop air and remove the catalyst.

[0111] Reaction: Load the pyridine catalyst that has undergone 60 h of hydrothermal treatment and been removed into a fluidized bed reactor at 450 °C. The raw material is a mixture of methyl ethyl aldehyde, with a feed rate of 2 mL / min. Feed ammonia at 3 L / min. Take samples once an hour and analyze the product content by gas chromatography. At the same time, record the weights of the raw material and the discharged material to calculate the yield.

[0112] Example 17:

[0113] Hydrothermal treatment: Charge 200 g of pyridine catalyst B into a fluidized bed at 600 °C. Feed air at 2 L / min and feed pure water at 8 mL / min through a feed pump into the fluidized bed via a preheater. Start timing from when the steam enters the fluidized bed and contacts the catalyst. Stop water feeding after 10 h of water flow, blow for 10 min, then stop air and remove the catalyst.

[0114] Reaction: Load the pyridine catalyst that has undergone 10 h of hydrothermal treatment and been removed into a fluidized bed reactor at 450 °C. The raw material is a mixture of methyl ethyl aldehyde, with a feed rate of 2 mL / min. Feed ammonia at 3 L / min. Take samples once an hour and analyze the product content by gas chromatography. At the same time, record the weights of the raw material and the discharged material to calculate the yield.

[0115] Example 18:

[0116] Hydrothermal treatment: Charge 200 g of pyridine catalyst B into a fluidized bed at 600 °C. Feed air at 2 L / min and feed pure water at 8 mL / min through a feed pump into the fluidized bed via a preheater. Start timing from when the steam enters the fluidized bed and contacts the catalyst. Stop water feeding after 20 h of water flow, blow for 10 min, then stop air and remove the catalyst.

[0117] Reaction: Load the pyridine catalyst that has been hydrothermally treated for 20 h and removed into a fluidized bed reactor at 450 °C. The raw materials are a mixture of methyl ethyl aldehydes, the feeding rate is 2 mL / min, 3 L / min of ammonia is introduced, samples are taken once per hour and the product content is analyzed by gas chromatography. At the same time, the weights of the raw materials and the discharged materials should also be recorded to calculate the yield.

[0118] Example 19:

[0119] Hydrothermal treatment: Load 200 g of pyridine catalyst B into a fluidized bed at 600 °C, introduce air at 2 L / min, and the feeding pump feeds 8 mL / min of pure water into the fluidized bed through a preheater. Start timing from when the steam enters the fluidized bed and contacts the catalyst. Stop water feeding after 30 h of water passing, stop air after blowing for 10 min, and then remove the catalyst.

[0120] Reaction: Load the pyridine catalyst that has been hydrothermally treated for 30 h and removed into a fluidized bed reactor at 450 °C. The raw materials are a mixture of methyl ethyl aldehydes, the feeding rate is 2 mL / min, 3 L / min of ammonia is introduced, samples are taken once per hour and the product content is analyzed by gas chromatography. At the same time, the weights of the raw materials and the discharged materials should also be recorded to calculate the yield.

[0121] Example 20:

[0122] Hydrothermal treatment: Load 200 g of pyridine catalyst B into a fluidized bed at 600 °C, introduce air at 2 L / min, and the feeding pump feeds 8 mL / min of pure water into the fluidized bed through a preheater. Start timing from when the steam enters the fluidized bed and contacts the catalyst. Stop water feeding after 60 h of water passing, stop air after blowing for 10 min, and then remove the catalyst.

[0123] Reaction: Load the pyridine catalyst that has been hydrothermally treated for 60 h and removed into a fluidized bed reactor at 450 °C. The raw materials are a mixture of methyl ethyl aldehydes, the feeding rate is 2 mL / min, 3 L / min of ammonia is introduced, samples are taken once per hour and the product content is analyzed by gas chromatography. At the same time, the weights of the raw materials and the discharged materials should also be recorded to calculate the yield.

[0124] Example 21:

[0125] Hydrothermal treatment: Load 200 g of pyridine catalyst B into a fluidized bed at 800 °C, introduce air at 2 L / min, and the feeding pump feeds 8 mL / min of pure water into the fluidized bed through a preheater. Start timing from when the steam enters the fluidized bed and contacts the catalyst. Stop water feeding after 10 h of water passing, stop air after blowing for 10 min, and then remove the catalyst.

[0126] Reaction: Load the pyridine catalyst that has been hydrothermally treated for 10 h and removed into a fluidized bed reactor at 450 °C. The raw material is a mixture of methyl ethyl aldehyde, with a feed rate of 2 mL / min, ammonia is fed at 3 L / min, samples are taken once an hour and the product content is analyzed by gas chromatography. At the same time, the weights of the raw material and the discharged material should also be recorded to calculate the yield.

[0127] Example 22:

[0128] Hydrothermal treatment: Load 200 g of pyridine catalyst B into an 800 °C fluidized bed, feed air at 2 L / min, and the feed pump feeds pure water at 8 mL / min into the fluidized bed through a preheater. Starting from the time when water vapor enters the fluidized bed and contacts the catalyst, stop feeding water after 20 h of water flow, stop air after blowing for 10 min, and then remove the catalyst.

[0129] Reaction: Load the pyridine catalyst that has been hydrothermally treated for 20 h and removed into a fluidized bed reactor at 450 °C. The raw material is a mixture of methyl ethyl aldehyde, with a feed rate of 2 mL / min, ammonia is fed at 3 L / min, samples are taken once an hour and the product content is analyzed by gas chromatography. At the same time, the weights of the raw material and the discharged material should also be recorded to calculate the yield.

[0130] Example 23:

[0131] Hydrothermal treatment: Load 200 g of pyridine catalyst B into an 800 °C fluidized bed, feed air at 2 L / min, and the feed pump feeds pure water at 8 mL / min into the fluidized bed through a preheater. Starting from the time when water vapor enters the fluidized bed and contacts the catalyst, stop feeding water after 30 h of water flow, stop air after blowing for 10 min, and then remove the catalyst.

[0132] Reaction: Load the pyridine catalyst that has been hydrothermally treated for 30 h and removed into a fluidized bed reactor at 450 °C. The raw material is a mixture of methyl ethyl aldehyde, with a feed rate of 2 mL / min, ammonia is fed at 3 L / min, samples are taken once an hour and the product content is analyzed by gas chromatography. At the same time, the weights of the raw material and the discharged material should also be recorded to calculate the yield.

[0133] Example 24:

[0134] Hydrothermal treatment: Load 200 g of pyridine catalyst B into an 800 °C fluidized bed, feed air at 2 L / min, and the feed pump feeds pure water at 8 mL / min into the fluidized bed through a preheater. Starting from the time when water vapor enters the fluidized bed and contacts the catalyst, stop feeding water after 60 h of water flow, stop air after blowing for 10 min, and then remove the catalyst.

[0135] Reaction: Load the pyridine catalyst that has been hydrothermally treated for 60 h and removed into a fluidized bed reactor at 450 °C. The raw material is a mixture of methyl ethyl aldehyde, with a feed rate of 2 mL / min, ammonia is fed at 3 L / min, samples are taken once an hour and the product content is analyzed by gas chromatography. At the same time, the weights of the raw material and the discharged material should also be recorded to calculate the yield.

[0136] Comparative Example 1:

[0137] 200 g of pyridine catalyst A was loaded into a 450°C fluidized bed reactor. The raw material was a mixture of methyl acetaldehyde at a feed rate of 2 mL / min and ammonia at 3 L / min. Samples were taken every hour and the product content was analyzed by gas chromatography. The weight of the raw material and the output was also recorded to calculate the yield.

[0138] Comparative Example 2:

[0139] 200 g of pyridine catalyst B was loaded into a 450°C fluidized bed reactor. The raw material was a mixture of methyl acetaldehyde at a feed rate of 2 mL / min and ammonia at 3 L / min. Samples were taken every hour and the product content was analyzed by gas chromatography. The weight of the raw material and the output was also recorded to calculate the yield.

[0140] Catalyst A and Catalyst B are molecular sieve small-scale synthesis catalysts produced by different manufacturers.

[0141] The following table shows the yields of the above embodiments and comparative examples after testing.

[0142]

[0143]

[0144] According to the examples, the longer the water treatment time, the higher the temperature of the hydrothermal treatment, and the greater the water flow, the more serious the damage to the stability of the catalyst. When compared at the same temperature and water flow, as the water flow time increases, the catalyst yield decreases, especially when the water flow is more than 30 hours, the catalyst yield decreases significantly.

[0145] The yields of catalysts A and B that were not treated with water in the formaldehyde acetaldehyde synthesis pyridine base reaction were significantly higher than the performance of catalysts A and B after water treatment under different conditions, as shown in Comparative Examples 1 and 2. In order to screen stable catalysts, the common method requires repeated regeneration of the catalysts to test the extent to which their performance has decreased. Here, we continuously regenerated catalysts A and B 20 times, observed the catalyst stability, and compared them with the hydrothermal stability.

[0146] Embodiment 25

[0147] Pyridine catalyst A was loaded into a fluidized bed reactor at a temperature of 450°C. The raw material was a mixture of methyl acetaldehyde, the feed rate was 2 mL / min, and the ammonia was fed at 3 L / min. Samples were taken once every hour to analyze the product content by gas chromatography, and the weight of the raw materials and the discharge was recorded to calculate the yield. Catalyst A that had completed one reaction was placed in a muffle furnace at 550°C for regeneration, which was a regeneration. The yield of the catalyst after 1 regeneration, 5 regenerations, 10 regenerations, 15 regenerations, and 20 regenerations of catalyst A was calculated.

[0148] Embodiment 26

[0149] Pyridine catalyst B is loaded into a fluidized bed reactor at a temperature of 450°C. The raw material is a mixture of methyl acetaldehyde, the feed rate is 2mL / min, and the ammonia is fed at 3L / min. Samples are taken once every hour to analyze the product content by gas chromatography, and the weight of the raw materials and the output is recorded to calculate the yield. Catalyst A that has completed one reaction is placed in a muffle furnace at 550°C for regeneration, which is a regeneration. Calculate the yield of the catalyst B after 1 regeneration, 5 regenerations, 10 regenerations, 15 regenerations, and 20 regenerations.

[0150] Table 2 Catalyst A and Catalyst B repeated regeneration yield data

[0151]

[0152] By comparing the hydrothermal regeneration stability and repeated regeneration of the catalyst, it can be seen that the hydrothermal stability test method can significantly shorten the test time, which is conducive to the rapid screening of catalysts. If the pyridine catalyst is hydrothermally treated for 30 hours and the catalyst yield does not decrease or decreases insignificantly, it means that the catalyst has good hydrothermal stability. If the catalyst hydrothermal treatment time is less than 30 hours and the yield decreases significantly, the catalyst hydrothermal stability is poor. If the pyridine catalyst is hydrothermally treated for 60 hours and the yield does not decrease significantly or does not decrease, it means that the catalyst hydrothermal temperature is very good, and this can be used as a standard for catalyst screening.

[0153] Although the present invention has been illustrated and described with specific embodiments, it will be appreciated that many other changes and modifications may be made without departing from the spirit and scope of the present invention. Therefore, it is intended to include all such changes and modifications within the scope of the present invention in the appended claims.

Claims

1. A pyridine catalyst stability testing method, characterized in that: include: S1, placing a pyridine catalyst in a fluidized bed reactor; S2: using a feed pump to feed water, the water is contacted with the pyridine catalyst after being vaporized, the contact time between the water vapor and the pyridine catalyst is taken as the time starting point, the water is passed through for 10-60 hours, and then the pyridine catalyst after the hydrothermal treatment is removed; S3, placing the hydrothermally treated pyridine catalyst in another fluidized bed reactor for reaction, feeding formaldehyde and acetaldehyde, and introducing ammonia gas at the same time; S4. Take samples at set time intervals, record the weight of the input and output materials, and calculate the yield.

2. The pyridine catalyst stability testing method according to claim 1, characterized in that: The temperature in the fluidized bed reactor in S1 is 500-800°C.

3. The pyridine catalyst stability testing method according to claim 1, characterized in that: In the above S1, after placing the pyridine catalyst in the fluidized bed reactor, the step of introducing air or nitrogen at a rate of 1-5 L / min is also included.

4. The pyridine catalyst stability testing method according to claim 1, characterized in that: The flow rate of water inlet in S2 is 2-8 mL / min.

5. The pyridine catalyst stability testing method according to claim 1, characterized in that: The temperature in the other fluidized bed reactor in S3 is 350-500°C.

6. The pyridine catalyst stability testing method according to claim 1, characterized in that: The feed flow rate in S3 is 2-10 mL / min.

7. The pyridine catalyst stability testing method according to any one of claims 1 to 6, characterized in that: The ammonia flow rate in S3 is 1-5 L / min.

8. A method for screening a pyridine catalyst, characterized in that: include: The pyridine catalyst is tested by the pyridine catalyst stability test method according to any one of claims 1 to 7, and the water treatment time is 30 hours and 60 hours respectively; Based on the test results, determine whether the pyridine catalyst is an unqualified catalyst, a qualified catalyst or a catalyst of high quality.

9. The pyridine catalyst screening method according to claim 8, characterized in that: Determining whether the pyridine catalyst is an unqualified catalyst, a qualified catalyst or a high-quality catalyst according to the test results includes: If the yield decreases by more than the first preset range after the test under the water treatment time of 30 hours, the pyridine catalyst is determined to be an unqualified catalyst; If the yield does not decrease or decreases within the first preset range after the test under the water treatment time of 30 hours, and the yield decreases by more than the second preset range after the test under the water treatment time of 60 hours, the pyridine catalyst is determined to be a qualified catalyst; If the yield decreases within the second preset range after testing under the condition that the water treatment time is 60 hours, the pyridine catalyst is determined to be a catalyst of high quality.

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