Acrylonitrile catalyst, process for its preparation and use

Abstract

The present application provides an acrylonitrile catalyst comprising a carrier and an active component, wherein the active component is a metal oxide having the general formula (I) A a B b Fe d Ni e Bi f (MoC c ) 12 O x (I). The present application also provides a method for preparing the acrylonitrile catalyst of the present application. The present application also provides the use of the acrylonitrile catalyst of the present application or the acrylonitrile catalyst prepared according to the method of the present application in the production of acrylonitrile by the ammoxidation of propylene. The acrylonitrile catalyst of the present application has a high acrylonitrile yield at a high propylene load. The catalyst not only has a high acrylonitrile yield at a high propylene load, but also has a low acrolein yield, so that the acrylonitrile recovery rate of the device is high to improve the production efficiency and economic benefit of the device.

Description

Technical Field

[0001] This invention belongs to the field of catalysts. Specifically, this invention relates to acrylonitrile catalysts, their preparation methods, and applications. Background Technology

[0002] Acrylonitrile is an important organic chemical raw material, produced through the ammoxidation of propylene. To obtain highly active and selective fluidized bed catalysts, researchers have continuously explored and made a series of improvements. These improvements mostly involve the active composition of the catalyst, focusing on the combination of active components to enhance the catalyst's activity and selectivity, thereby increasing the single-pass yield of acrylonitrile and improving production load.

[0003] After more than 50 years of development, acrylonitrile production via ammonia oxidation still faces a demand gap in recent years. The main trend in acrylonitrile production is to build new large-scale plants to achieve economies of scale, further reducing raw material and energy consumption while increasing production capacity. Domestic acrylonitrile plant capacity is expected to double, bringing the total production capacity close to market demand. Therefore, future competition among acrylonitrile plants will not only focus on the economic benefits of acrylonitrile production efficiency but also on environmentally friendly, clean production. This involves ensuring acrylonitrile yield while further reducing acrolein yield, thereby improving the acrylonitrile refining and recovery rate and enhancing the overall economic efficiency of the plant.

[0004] When expanding existing acrylonitrile plants, the catalyst loading must be kept relatively low. Therefore, the replacement catalyst must maintain a high acrylonitrile yield under higher propylene loads. Once the reactor size and production capacity are determined, the amount of catalyst loaded into the reactor is related to the catalyst's load capacity, i.e., WWH (While the catalyst can withstand). WWH is defined as the number of tons of propylene processed per ton of catalyst per hour. When the reactor feed rate increases, if the catalyst load remains constant, the catalyst loading must also increase accordingly. However, the cooling water pipe height in the original fluidized bed reactor design is insufficient, so the fluidization height of the catalyst in the reactor may exceed the height of the cooling water pipes. Furthermore, the increased reactor feed rate leads to a significant increase in the operating linear velocity. The combined effect of these two changes may cause an increase in the dilute phase temperature of the reactor, resulting in increased carbon dioxide production and decreased acrylonitrile selectivity. Therefore, a catalyst with a higher catalyst load can prevent these problems.

[0005] Theoretically, increasing the catalyst loading should increase the catalyst's adsorption and activation capacity for propylene. However, there are currently no reports on any single element in a catalyst that can enhance its adsorption and activation capacity for propylene. US5093299 and US5212137 describe a catalyst for the ammoxidation of propylene to acrylonitrile using a molybdenum, bismuth, iron, nickel, magnesium, potassium, and cesium system. These patents describe a catalyst that can operate at typically slightly lower reaction temperatures, exhibits high catalytic activity and excellent redox stability, and is therefore suitable for operation under lower air / propylene ratio conditions. However, it should be noted that the examples in these patents are conducted under fixed-bed conditions at a reaction temperature of 430°C, without mentioning specific reaction pressures and operating loads, and without addressing the catalyst's performance under high pressure and high load conditions.

[0006] Article 8-27089 describes a method for manufacturing acrylonitrile, which uses a catalyst system of molybdenum, bismuth, iron, magnesium and tungsten to carry out the ammoxidation reaction of propylene. The conditions investigated in the examples of this literature are at atmospheric pressure.

[0007] Regarding the acrylonitrile yield in the initial stage of the reaction, the catalysts disclosed in the aforementioned patent documents have been significantly improved. However, none of the aforementioned patents not only fail to provide data on acrylonitrile yield under high propylene loads, but also fail to provide data on acrylonitrile and acrolein yields under high propylene loads and high reaction pressures.

[0008] CN102892496 discloses a highly efficient ammonia oxidation method and a mixed metal oxide catalyst. Specifically, this prior art discloses a method and catalyst for producing acrylonitrile, acetonitrile, and hydrogen cyanide; however, its preparation process is complex, and the evaluation process conditions are carried out under low loading of 0.06 h⁻¹ and low pressure of 10 psig.

[0009] CN1084228C discloses an ammonia oxidation catalyst composition and a method for producing acrylonitrile or methacrylonitrile using the same. Specifically, this prior art discloses a catalyst for the ammonia oxidation of propylene to acrylonitrile containing at least one of molybdenum, bismuth, cerium, iron, nickel, magnesium, or zinc, and at least one of potassium, cesium, or rubidium. This patent discloses that its catalyst can effectively prevent a decrease in acrylonitrile yield even with extended reaction time; however, its catalyst evaluation was conducted under relatively low reaction pressure and low operating load conditions.

[0010] Currently, there is an urgent need for an acrylonitrile catalyst that can still achieve a high acrylonitrile yield under high propylene loads in order to improve the production efficiency and economic benefits of the plant. Summary of the Invention

[0011] One object of the present invention is to provide an acrylonitrile catalyst that maintains a high acrylonitrile yield even under high propylene loading. This catalyst not only exhibits a high acrylonitrile yield under high propylene loading but also a low acrolein yield, thereby resulting in a high acrylonitrile recovery rate in the plant and improving its production efficiency and economic benefits. Another object of the present invention is to provide a method for preparing the catalyst of the present invention. A further object of the present invention is to provide applications of the said catalyst.

[0012] The above-mentioned objective of the present invention is achieved through the following technical solution.

[0013] In a first aspect, the present invention provides an acrylonitrile catalyst comprising a support and an active component, wherein the active component is a metal oxide having the following general formula (I).

[0014] A a B b Fe d Ni e Bi f (MoC c ) 12 O x (I)

[0015] in,

[0016] A is selected from at least one of the elements Li, Na, K, Rb, and Cs;

[0017] B is selected from at least one of the elements W, Ga, Nb, Mg, Ca, Cr, and Co;

[0018] C is selected from at least one of the elements Ce, Nd, and Pr;

[0019] a, b, c, d, e, f, and x represent the number of atoms of each element;

[0020] a ranges from 0.01 to 2.50;

[0021] b is 0.10 to 10.00;

[0022] c is 0.04 to 0.50;

[0023] d ranges from 0.01 to 5.00;

[0024] e ranges from 1.00 to 10.00;

[0025] f ranges from 0.01 to 5.00;

[0026] x is the number of oxygen atoms required to satisfy the valence of other elements;

[0027] The acrylonitrile catalyst is prepared by a method comprising the following steps:

[0028] (1) After dissolving raw material A, material i is obtained;

[0029] (2) The raw material of molybdenum is dissolved to obtain material ii;

[0030] (3) After dissolving the raw materials of B and Fe, Bi and Ni, material iii is obtained;

[0031] (4) After dissolving the raw material of C, material iv is obtained, wherein the C ions in the raw material of C have a +3 valence, that is, C 3+ ;

[0032] (5) The material ii and the material iv are mixed under stirring to obtain material v.

[0033] (6) Mix material i with carrier sol, and add material iii and material v in sequence under stirring to obtain catalyst slurry;

[0034] (7) The catalyst slurry is spray-dried to obtain the catalyst precursor;

[0035] (8) The catalyst precursor is calcined in an oxidizing atmosphere to obtain the acrylonitrile catalyst.

[0036] The inventors of this application unexpectedly discovered that the catalyst prepared by the method of this invention exhibits excellent catalytic performance, such as a high acrylonitrile yield. Not wishing to be bound by theory, it is believed that the excellent catalytic performance of the catalyst of this invention may be attributed to controlling the C ions in the feedstock to have a +3 valence in step (4) of the method of this invention, i.e., C... 3+ Simultaneously, materials ii and iv are premixed, thereby the catalyst of the present invention contains chemically bonded (MoC) states. c ) 12 Substance. This chemically bonded state (MoC) c ) 12 The substance can stabilize molybdenum, thereby improving the catalyst's stability. Furthermore, the effective combination of Mo and C elements promotes the enhancement of the catalyst's redox performance, improving its performance under high pressure and high load conditions.

[0037] Preferably, in the acrylonitrile catalyst of the present invention, the content of the support is 30-70% by weight, based on the total weight of the acrylonitrile catalyst.

[0038] Preferably, in the acrylonitrile catalyst of the present invention, the content of the active component is 30-70% by weight, based on the total weight of the acrylonitrile catalyst.

[0039] Preferably, in the acrylonitrile catalyst of the present invention, the support is selected from at least one of silica, alumina, titanium dioxide and zirconium oxide.

[0040] Preferably, in the acrylonitrile catalyst of the present invention, a is 0.05 to 1.50.

[0041] Preferably, in the acrylonitrile catalyst of the present invention, b is 1.50 to 9.00.

[0042] Preferably, in the acrylonitrile catalyst of the present invention, c is 0.08 to 0.30.

[0043] Preferably, in the acrylonitrile catalyst of the present invention, d is 0.05 to 3.00.

[0044] Preferably, in the acrylonitrile catalyst of the present invention, e is 1.50 to 9.00.

[0045] Preferably, in the acrylonitrile catalyst of the present invention, f is 0.05 to 3.00.

[0046] Preferably, in the acrylonitrile catalyst of the present invention, C in step (4) 3+ The ionic radius is 98-102 pm.

[0047] Preferably, in the acrylonitrile catalyst of the present invention, C in step (4) 3+ Average ionic radius and Mo 6+ The ratio of their ionic radii is 1.51 to 1.57:1.

[0048] In a second aspect, the present invention provides a method for preparing the acrylonitrile catalyst of the present invention, comprising the following steps:

[0049] (1) After dissolving raw material A, material i is obtained;

[0050] (2) The raw material of molybdenum is dissolved to obtain material ii;

[0051] (3) After dissolving the raw materials of B and Fe, Bi and Ni, material iii is obtained;

[0052] (4) After dissolving the raw material of C, material iv is obtained, wherein the C ions in the raw material of C have a +3 valence, that is, C 3+ ;

[0053] (5) The material ii and the material iv are mixed under stirring to obtain material v.

[0054] (6) Mix material i with carrier sol, and add material iii and material v in sequence under stirring to obtain catalyst slurry;

[0055] (7) The catalyst slurry is spray-dried to obtain the catalyst precursor;

[0056] (8) The catalyst precursor is calcined in an oxidizing atmosphere to obtain the acrylonitrile catalyst.

[0057] Preferably, in the method described in this invention, C in step (4) 3+ The ionic radius is 98-102 pm.

[0058] Preferably, in the method described in this invention, C in step (4) 3+ The average ionic radius and the Mo in the molybdenum feedstock 6+ The ratio of their ionic radii is 1.51 to 1.57:1.

[0059] In the method of the present invention, C 3+ The ionic radius is not specifically limited and can be 98-102 pm. When C 3+ When the ionic radius is below 98 pm, it causes interaction with Mo. 6+ Poor matching degree, unable to play a role in stabilizing molybdenum; when C 3+ When the ionic radius is higher than 102 pm, it also causes [the same effect as] Mo. 6+ The matching degree is poor, and the redox function of element C cannot be effectively utilized.

[0060] In the method of the present invention, C 3+ Average ionic radius and Mo 6+ The ratio of ionic radii is not particularly limited and can be 1.51 to 1.57:1. When C 3+ Average ionic radius and Mo 6+ When the ratio of the ionic radii is less than 1.51, it causes a reaction with Mo. 6+ Poor matching degree, unable to play a role in stabilizing molybdenum; when C 3+ Average ionic radius and Mo 6+ When the ratio of ionic radii is greater than 1.57, it also causes a similar effect to Mo. 6+ The matching degree is poor, and the redox function of element C cannot be effectively utilized.

[0061] As a specific embodiment of the present invention, the molybdenum in the catalyst of the present invention can be molybdenum in any oxide form, such as molybdenum oxide or molybdate. Water-soluble molybdate is preferred.

[0062] In a specific embodiment of the present invention, the alkali metal in the catalyst can be in oxide form or a salt that can produce an oxide upon calcination, such as a nitrate or chloride. Nitrates or inorganic bases are readily available and easily soluble.

[0063] As a specific embodiment of the present invention, the iron, nickel and bismuth in the catalyst can be in the form of oxides, or any compound that can generate oxides during calcination can be used. Water-soluble salts are preferred, and hydrated nitrates or nitrates are most preferred.

[0064] As a specific embodiment of the present invention, the cerium, neodymium and praseodymium in the catalyst can be in oxide form, or any compound that can generate oxides during calcination can be used. Water-soluble salts are preferred, and hydrated nitrates or nitrates are most preferred.

[0065] As a specific embodiment of the present invention, cadmium in the catalyst can be in the form of an oxide, or any compound that can generate an oxide during calcination, preferably a water-soluble salt. Specifically, cadmium is preferably introduced in the form of a nitrate.

[0066] As a specific embodiment of the present invention, the tungsten, gallium, niobium, magnesium, calcium, chromium and cobalt in the catalyst can be in the form of oxides, or any compound that can generate oxides during calcination can be used, with water-soluble salts being more preferred.

[0067] Thirdly, the present invention provides the application of the acrylonitrile catalyst of the present invention or the acrylonitrile catalyst prepared according to the method of the present invention in the ammoxidation of propylene to acrylonitrile.

[0068] The present invention has the following beneficial effects:

[0069] The acrylonitrile catalyst of the present invention maintains a high acrylonitrile yield even under high propylene loads. This catalyst not only exhibits a high acrylonitrile yield under high propylene loads but also a low acrolein yield, resulting in a high acrylonitrile recovery rate in the plant, thereby improving the plant's production efficiency and economic benefits.

[0070] The acrylonitrile catalyst prepared by the method of the present invention contains chemically bonded (MoC) atoms in its general formula. c ) 12 Substance. This chemically bonded state (MoC) c ) 12 The substance can stabilize molybdenum, making it less prone to loss, and can also more effectively exert the redox effect of carbon. Detailed Implementation

[0071] The present invention will be further described below with reference to specific embodiments, but this does not constitute any limitation on the present invention.

[0072] Example 1

[0073] 1. Catalyst Preparation

[0074] Add 15 g of water to 8.41 g of potassium hydroxide and heat to dissolve, obtaining material i; add 330.5 g of ammonium heptamolybdate (NH4)6Mo7O 24 • 4H2O is dissolved in 300g of hot water at 80℃ to obtain material ii; 112.9g of bismuth nitrate Bi(NO3)3·5H2O, 159.2g of magnesium nitrate Mg(NO3)2·6H2O, 250.8g of nickel nitrate Ni(NO3)2·6H2O, and 114.0g of iron nitrate Fe(NO3)3·9H2O are mixed, 100g of water is added, and the mixture is heated to dissolve to obtain material iii; 169.9g of neodymium nitrate Nd(NO3)3·6H2O is added to 100g of water, and the mixture is heated to dissolve to obtain material iv. Material ii and material iv are mixed evenly with stirring to obtain material v.

[0075] Material i was mixed with 1250 g of silica sol with a weight concentration of 40%. Materials iii and v were then added sequentially under stirring, and the mixture was thoroughly stirred to obtain a slurry. The slurry was heat-treated at 100°C for 25 minutes, and then the heat-treated slurry was subjected to microsphere forming in a spray dryer using conventional methods. Finally, microspheres with an inner diameter of 89 mm and a length of 1700 mm were formed. The catalyst was calcined in a rotary calciner at 585°C for 2.0 hours to obtain a catalyst composition, by mass fraction:

[0076] 50% K 0.80 Mg 4.00 Fe 1.80 Ni 5.50 Bi 1.50 (MoNd 0.21 ) 12.0 O x +50% SiO2

[0077] 2. Catalyst Evaluation

[0078] The reaction conditions are:

[0079] millimeter fluidized bed reactor

[0080] Reaction temperature 430℃

[0081] Reaction pressure 84 kPa

[0082] Catalyst loading: 400 grams

[0083] Catalyst propylene loading (WWH) 0.10 h -1

[0084] Raw material ratio (moles): C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0085] The results are shown in Table 1.

[0086] Example 2

[0087] 1. Catalyst Preparation

[0088] Add 15 g of water to 8.44 g of potassium hydroxide and heat to dissolve, obtaining material i; add 331.5 g of ammonium heptamolybdate (NH4)6Mo7O 24 • 4H2O is dissolved in 300g of hot water at 80℃ to obtain material ii; 113.3g of bismuth nitrate Bi(NO3)3·5H2O, 159.7g of magnesium nitrate Mg(NO3)2·6H2O, 251.6g of nickel nitrate Ni(NO3)2·6H2O, and 114.4g of ferric nitrate Fe(NO3)3·9H2O are mixed, 100g of water is added, and the mixture is heated to dissolve to obtain material iii; 170.4g of cerium nitrate Ce(NO3)3·6H2O is added to 100g of water, and the mixture is heated to dissolve to obtain material iv. Material ii and material iv are mixed evenly with stirring to obtain material v.

[0089] Material i was mixed with 1250 g of silica sol with a weight concentration of 40%. Materials iii and v were then added sequentially under stirring, and the mixture was thoroughly stirred to obtain a slurry. The slurry was heat-treated at 100°C for 25 minutes, and then the heat-treated slurry was subjected to microsphere forming in a spray dryer using conventional methods. Finally, microspheres with an inner diameter of 89 mm and a length of 1700 mm were formed. The catalyst was calcined in a rotary calciner at 585°C for 2.0 hours to obtain a catalyst composition, by mass fraction:

[0090] 50% K 0.80 Mg 4.00 Fe 1.80 Ni 5.50 Bi 1.50 (MoCe 0.21 ) 12.0 O x +50% SiO2

[0091] 2. Catalyst Evaluation

[0092] The reaction conditions are:

[0093] millimeter fluidized bed reactor

[0094] Reaction temperature 430℃

[0095] Reaction pressure 84 kPa

[0096] Catalyst loading: 400 grams

[0097] Catalyst propylene loading (WWH) 0.10 h -1

[0098] Raw material ratio (moles): C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0099] The results are shown in Table 1.

[0100] Example 3

[0101] 1. Catalyst Preparation

[0102] Add 15 g of water to 8.43 g of potassium hydroxide and heat to dissolve, obtaining material i; add 331.3 g of ammonium heptamolybdate (NH4)6Mo7O 24 • 4H2O is dissolved in 300g of hot water at 80℃ to obtain material ii; 113.2g of bismuth nitrate Bi(NO3)3·5H2O, 159.6g of magnesium nitrate Mg(NO3)2·6H2O, 251.4g of nickel nitrate Ni(NO3)2·6H2O, and 114.3g of iron nitrate Fe(NO3)3·9H2O are mixed, 100g of water is added, and the mixture is heated to dissolve to obtain material iii; 168.9g of praseodymium nitrate Pr(NO3)3·6H2O is added to 100g of water, and the mixture is heated to dissolve to obtain material iv. Material ii and material iv are mixed evenly with stirring to obtain material v.

[0103] Material i was mixed with 1250 g of silica sol with a weight concentration of 40%. Materials iii and v were then added sequentially under stirring, and the mixture was thoroughly stirred to obtain a slurry. The slurry was heat-treated at 100°C for 25 minutes, and then the heat-treated slurry was subjected to microsphere forming in a spray dryer using conventional methods. Finally, microspheres with an inner diameter of 89 mm and a length of 1700 mm were formed. The catalyst was calcined in a rotary calciner at 585°C for 2.0 hours to obtain a catalyst composition, by mass fraction:

[0104] 50% K 0.80 Mg 4.00 Fe 1.80 Ni 5.50 Bi 1.50 (MoPr 0.21 ) 12.0 O x +50% SiO2

[0105] 2. Catalyst Evaluation

[0106] The reaction conditions are:

[0107] millimeter fluidized bed reactor

[0108] Reaction temperature 430℃

[0109] Reaction pressure 84 kPa

[0110] Catalyst loading: 400 grams

[0111] Catalyst propylene loading (WWH) 0.10 h -1

[0112] Raw material ratio (moles): C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0113] The results are shown in Table 1.

[0114] Example 4

[0115] 1. Catalyst Preparation

[0116] Add 15 g of water to 8.45 g of potassium hydroxide and heat to dissolve, obtaining material i; add 332.0 g of ammonium heptamolybdate (NH4)6Mo7O 24 • 4H2O is dissolved in 300g of hot water at 80℃ to obtain material ii; 113.5g of bismuth nitrate Bi(NO3)3·5H2O, 159.9g of magnesium nitrate Mg(NO3)2·6H2O, 251.9g of nickel nitrate Ni(NO3)2·6H2O, and 114.5g of iron nitrate Fe(NO3)3·9H2O are mixed, 100g of water is added, and the mixture is heated to dissolve to obtain material iii; 65.0g of neodymium nitrate Nd(NO3)3·6H2O and 100.7g of praseodymium nitrate Pr(NO3)3·6H2O are added to 100g of water, and the mixture is heated to dissolve to obtain material iv. Material ii and material iv are mixed evenly with stirring to obtain material v.

[0117] Material i was mixed with 1250 g of silica sol with a weight concentration of 40%. Materials iii and v were then added sequentially under stirring, and the mixture was thoroughly stirred to obtain a slurry. The slurry was heat-treated at 100°C for 25 minutes, and then the heat-treated slurry was subjected to microsphere forming in a spray dryer using conventional methods. Finally, microspheres with an inner diameter of 89 mm and a length of 1700 mm were formed. The catalyst was calcined in a rotary calciner at 585°C for 2.0 hours to obtain a catalyst composition, by mass fraction:

[0118] 50% K 0.80 Mg 4.00 Fe 1.80 Ni 5.50 Bi 1.50 (MoNd 0.08 Pr 0.125 ) 12.0 O x +50% SiO2

[0119] 2. Catalyst Evaluation

[0120] The reaction conditions are:

[0121] millimeter fluidized bed reactor

[0122] Reaction temperature 430℃

[0123] Reaction pressure 84 kPa

[0124] Catalyst loading: 400 grams

[0125] Catalyst propylene loading (WWH) 0.10 h -1

[0126] Raw material ratio (moles): C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0127] The results are shown in Table 1.

[0128] Example 5

[0129] 1. Catalyst Preparation

[0130] Add 15 g of water to 8.46 g of potassium hydroxide and heat to dissolve, obtaining material i; add 332.4 g of ammonium heptamolybdate (NH4)6Mo7O 24 • 4H2O is dissolved in 300g of hot water at 80℃ to obtain material ii; 113.6g of bismuth nitrate Bi(NO3)3·5H2O, 160.1g of magnesium nitrate Mg(NO3)2·6H2O, 252.2g of nickel nitrate Ni(NO3)2·6H2O, and 114.7g of iron nitrate Fe(NO3)3·9H2O are mixed, 100g of water is added, and the mixture is heated to dissolve to obtain material iii; 65.1g of cerium nitrate Ce(NO3)3·6H2O and 100.9g of praseodymium nitrate Pr(NO3)3·6H2O are added to 100g of water, and the mixture is heated to dissolve to obtain material iv. Material ii and material iv are mixed evenly with stirring to obtain material v.

[0131] Material i was mixed with 1250 g of silica sol with a weight concentration of 40%. Materials iii and v were then added sequentially under stirring, and the mixture was thoroughly stirred to obtain a slurry. The slurry was heat-treated at 100°C for 25 minutes, and then the heat-treated slurry was subjected to microsphere forming in a spray dryer using conventional methods. Finally, microspheres with an inner diameter of 89 mm and a length of 1700 mm were formed. The catalyst was calcined in a rotary calciner at 585°C for 2.0 hours to obtain a catalyst composition, by mass fraction:

[0132] 50% K 0.80 Mg 4.00 Fe1.80 Ni 5.50 Bi 1.50 (MoCe 0.08 Pr 0.125 ) 12.0 O x +50% SiO2

[0133] 2. Catalyst Evaluation

[0134] The reaction conditions are:

[0135] millimeter fluidized bed reactor

[0136] Reaction temperature 430℃

[0137] Reaction pressure 84 kPa

[0138] Catalyst loading: 400 grams

[0139] Catalyst propylene loading (WWH) 0.10 h -1

[0140] Raw material ratio (moles): C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0141] The results are shown in Table 1.

[0142] Example 6

[0143] 1. Catalyst Preparation

[0144] Add 15 grams of water to 8.45 grams of potassium hydroxide and heat to dissolve, obtaining material i; add 331.9 grams of ammonium heptamolybdate (NH4)6Mo7O 24 • 4H2O is dissolved in 300g of hot water at 80℃ to obtain material ii; 113.4g of bismuth nitrate Bi(NO3)3·5H2O, 159.9g of magnesium nitrate Mg(NO3)2·6H2O, 251.9g of nickel nitrate Ni(NO3)2·6H2O, and 114.5g of iron nitrate Fe(NO3)3·9H2O are mixed, 100g of water is added, and the mixture is heated to dissolve to obtain material iii; 65.0g of cerium nitrate Ce(NO3)3·6H2O and 101.6g of neodymium nitrate Nd(NO3)3·6H2O are added to 100g of water, and the mixture is heated to dissolve to obtain material iv. Material ii and material iv are mixed evenly with stirring to obtain material v.

[0145] Material i was mixed with 1250 g of silica sol with a weight concentration of 40%. Materials iii and v were then added sequentially under stirring, and the mixture was thoroughly stirred to obtain a slurry. The slurry was heat-treated at 100°C for 25 minutes, and then the heat-treated slurry was subjected to microsphere forming in a spray dryer using conventional methods. Finally, microspheres with an inner diameter of 89 mm and a length of 1700 mm were formed. The catalyst was calcined in a rotary calciner at 585°C for 2.0 hours to obtain a catalyst composition, by mass fraction:

[0146] 50% K 0.80 Mg 4.00 Fe 1.80 Ni 5.50 Bi 1.50 (MoCe 0.08 Nd 0.125 ) 12.0 O x +50% SiO2

[0147] 2. Catalyst Evaluation

[0148] The reaction conditions are:

[0149] millimeter fluidized bed reactor

[0150] Reaction temperature 430℃

[0151] Reaction pressure 84 kPa

[0152] Catalyst loading: 400 grams

[0153] Catalyst propylene loading (WWH) 0.10 h -1

[0154] Raw material ratio (moles): C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0155] The results are shown in Table 1.

[0156] A comparison of Examples 4-6 with Examples 1-3 shows that the combination of rare earth elements has a synergistic effect in improving the yield of acrylonitrile.

[0157] Comparative Example 1

[0158] 1. Catalyst Preparation

[0159] Add 15 g of water to 8.45 g of potassium hydroxide and heat to dissolve, obtaining material i; add 331.8 g of ammonium heptamolybdate (NH4)6Mo7O 24• 4H2O is dissolved in 300g of hot water at 80℃ to obtain material ii; 113.4g of bismuth nitrate Bi(NO3)3·5H2O, 159.8g of magnesium nitrate Mg(NO3)2·6H2O, 251.8g of nickel nitrate Ni(NO3)2·6H2O, and 114.5g of iron nitrate Fe(NO3)3·9H2O are mixed, 100g of water is added, and the mixture is heated to dissolve to obtain material iii; 170.0g of lanthanum nitrate La(NO3)3·6H2O is added to 100g of water, and the mixture is heated to dissolve to obtain material iv. Material ii and material iv are mixed evenly with stirring to obtain material v.

[0160] Material i was mixed with 1250 g of silica sol with a weight concentration of 40%. Materials iii and v were then added sequentially under stirring, and the mixture was thoroughly stirred to obtain a slurry. The slurry was heat-treated at 100°C for 25 minutes, and then the heat-treated slurry was subjected to microsphere forming in a spray dryer using conventional methods. Finally, microspheres with an inner diameter of 89 mm and a length of 1700 mm were formed. The catalyst was calcined in a rotary calciner at 585°C for 2.0 hours to obtain a catalyst composition, by mass fraction:

[0161] 50% K 0.80 Mg 4.00 Fe 1.80 Ni 5.50 Bi 1.50 (MoLa 0.21 ) 12.0 O x +50% SiO2

[0162] 2. Catalyst Evaluation

[0163] The reaction conditions are:

[0164] millimeter fluidized bed reactor

[0165] Reaction temperature 430℃

[0166] Reaction pressure 84 kPa

[0167] Catalyst loading: 400 grams

[0168] Catalyst propylene loading (WWH) 0.10 h -1

[0169] Raw material ratio (moles): C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0170] The results are shown in Table 1.

[0171] Comparative Example 2

[0172] 1. Catalyst Preparation

[0173] Dissolve 8.25 g of potassium hydroxide in 15 g of water by heating to obtain material i; dissolve 324.3 g of ammonium heptamolybdate (NH4)6Mo7O 24 • 4H2O is dissolved in 300g of hot water at 80℃ to obtain material ii; 110.8g of bismuth nitrate Bi(NO3)3·5H2O, 156.2g of magnesium nitrate Mg(NO3)2·6H2O, 246.1g of nickel nitrate Ni(NO3)2·6H2O, and 111.9g of ferric nitrate Fe(NO3)3·9H2O are mixed, 100g of water is added, and the mixture is heated to dissolve to obtain material iii; 176.1g of thulium nitrate Tm(NO3)3·6H2O is added to 100g of water, and the mixture is heated to dissolve to obtain material iv. Material ii and material iv are mixed evenly with stirring to obtain material v.

[0174] Material i was mixed with 1250 g of silica sol with a weight concentration of 40%. Materials iii and v were then added sequentially under stirring, and the mixture was thoroughly stirred to obtain a slurry. The slurry was heat-treated at 100°C for 25 minutes, and then the heat-treated slurry was subjected to microsphere forming in a spray dryer using conventional methods. Finally, microspheres with an inner diameter of 89 mm and a length of 1700 mm were formed. The catalyst was calcined in a rotary calciner at 585°C for 2.0 hours to obtain a catalyst composition, by mass fraction:

[0175] 50% K 0.80 Mg 4.00 Fe 1.80 Ni 5.50 Bi 1.50 (MoTm 0.21 ) 12.0 O x +50% SiO2

[0176] 2. Catalyst Evaluation

[0177] The reaction conditions are:

[0178] millimeter fluidized bed reactor

[0179] Reaction temperature 430℃

[0180] Reaction pressure 84 kPa

[0181] Catalyst loading: 400 grams

[0182] Catalyst propylene loading (WWH) 0.10 h -1

[0183] Raw material ratio (moles): C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0184] The results are shown in Table 1.

[0185] Tm 3+ The ionic radius is 86.9 pm, which is less than 98 pm.

[0186] As can be seen from the comparison between Comparative Examples 1-2 and Examples 1-3, La 3+ The ionic radius is 106.1 pm, which is greater than 102 pm, and Tm 3+ The ionic radius is 86.9 pm, which is less than 98 pm. The size of the ionic radius plays a key role in reducing the yield of acrolein impurities and increasing the yield of acrylonitrile.

[0187] Comparative Example 3

[0188] 1. Catalyst Preparation

[0189] Add 15 g of water to 8.41 g of potassium hydroxide and heat to dissolve, obtaining material i; add 330.5 g of ammonium heptamolybdate (NH4)6Mo7O 24 • Dissolve 4H2O in 300g of hot water at 80℃ to obtain material ii; Mix 112.9g of bismuth nitrate Bi(NO3)3·5H2O, 159.2g of magnesium nitrate Mg(NO3)2·6H2O, 250.8g of nickel nitrate Ni(NO3)2·6H2O, and 114.0g of ferric nitrate Fe(NO3)3·9H2O, add 100g of water, heat to dissolve, and obtain material iii; Add 169.9g of neodymium nitrate Nd(NO3)3·6H2O to 100g of water, heat to dissolve, and obtain material iv.

[0190] Material i was mixed with 1250 g of silica sol with a weight concentration of 40%. Materials ii, iii, and iv were added sequentially under stirring, and the mixture was thoroughly stirred to obtain a slurry. The slurry was heat-treated at 100°C for 25 minutes, and then microspheres were formed in a spray dryer using conventional methods. Finally, microspheres with an inner diameter of 89 mm and a length of 1700 mm were formed. The catalyst was calcined in a rotary calciner at 585°C for 2.0 hours to obtain a catalyst composition, by mass fraction:

[0191] 50% K 0.80 Mg 4.00 Nd 2.52 Fe 1.80 Ni 5.50 Bi 1.50 Mo 12.0 O x +50% SiO2

[0192] 2. Catalyst Evaluation

[0193] The reaction conditions are:

[0194] millimeter fluidized bed reactor

[0195] Reaction temperature 430℃

[0196] Reaction pressure 84 kPa

[0197] Catalyst loading: 400 grams

[0198] Catalyst propylene loading (WWH) 0.10 h -1

[0199] Raw material ratio (moles): C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0200] The results are shown in Table 1.

[0201] As can be seen from the comparison between Comparative Example 3 and Example 1, the pre-uniform mixing of Mo and rare earth elements has a significant effect on reducing the yield of acrolein impurities and increasing the yield of acrylonitrile.

[0202] Comparative Example 4

[0203] 1. Catalyst Preparation

[0204] Add 15 g of water to 8.37 g of potassium hydroxide and heat to dissolve, obtaining material i; add 328.9 g of ammonium heptamolybdate (NH4)6Mo7O 24 • 4H2O is dissolved in 300g of hot water at 80℃ to obtain material ii; 112.4g of bismuth nitrate Bi(NO3)3·5H2O, 158.4g of magnesium nitrate Mg(NO3)2·6H2O, 249.6g of nickel nitrate Ni(NO3)2·6H2O, and 113.5g of ferric nitrate Fe(NO3)3·9H2O are mixed, 100g of water is added, and the mixture is heated to dissolve to obtain material iii; 173.0g of samarium nitrate Sm(NO3)3·6H2O is added to 100g of water, and the mixture is heated to dissolve to obtain material iv. Material ii and material iv are mixed evenly with stirring to obtain material v.

[0205] Material i was mixed with 1250 g of silica sol with a weight concentration of 40%. Materials iii and v were then added sequentially under stirring, and the mixture was thoroughly stirred to obtain a slurry. The slurry was heat-treated at 100°C for 25 minutes, and then the heat-treated slurry was subjected to microsphere forming in a spray dryer using conventional methods. Finally, microspheres with an inner diameter of 89 mm and a length of 1700 mm were formed. The catalyst was calcined in a rotary calciner at 585°C for 2.0 hours to obtain a catalyst composition, by mass fraction:

[0206] 50% K 0.80 Mg 4.00 Fe1.80 Ni 5.50 Bi 1.50 (MoSm 0.21 ) 12.0 O x +50% SiO2

[0207] 2. Catalyst Evaluation

[0208] The reaction conditions are:

[0209] millimeter fluidized bed reactor

[0210] Reaction temperature 430℃

[0211] Reaction pressure 84 kPa

[0212] Catalyst loading: 400 grams

[0213] Catalyst propylene loading (WWH) 0.10 h -1

[0214] Raw material ratio (moles): C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0215] The results are shown in Table 1.

[0216] As can be seen from the comparison between Comparative Example 4 and Examples 1-3, the rare earth element ion Mo 6+ The radius ratio plays a crucial role in reducing the yield of acrolein impurities and increasing the yield of acrylonitrile.

[0217] Comparative Example 5

[0218] 1. Catalyst Preparation

[0219] Add 15 g of water to 8.44 g of potassium hydroxide and heat to dissolve, obtaining material i; add 331.5 g of ammonium heptamolybdate (NH4)6Mo7O 24 • 4H2O is dissolved in 300g of hot water at 80℃ to obtain material ii; 113.3g of bismuth nitrate Bi(NO3)3·5H2O, 159.7g of magnesium nitrate Mg(NO3)2·6H2O, 251.6g of nickel nitrate Ni(NO3)2·6H2O, and 114.4g of ferric nitrate Fe(NO3)3·9H2O are mixed, 100g of water is added, and the mixture is heated to dissolve to obtain material iii; 215.1g of cerium ammonium nitrate (NH4)2Ce(NO3)6 is added to 100g of water, and the mixture is heated to dissolve to obtain material iv. Material ii and material iv are mixed evenly with stirring to obtain material v.

[0220] Material i was mixed with 1250 g of silica sol with a weight concentration of 40%. Materials iii and v were then added sequentially under stirring, and the mixture was thoroughly stirred to obtain a slurry. The slurry was heat-treated at 100°C for 25 minutes, and then the heat-treated slurry was subjected to microsphere forming in a spray dryer using conventional methods. Finally, microspheres with an inner diameter of 89 mm and a length of 1700 mm were formed. The catalyst was calcined in a rotary calciner at 585°C for 2.0 hours to obtain a catalyst composition, by mass fraction:

[0221] 50% K 0.80 Mg 4.00 Fe 1.80 Ni 5.50 Bi 1.50 (MoCe 0.21 ) 12.0 O x +50% SiO2

[0222] 2. Catalyst Evaluation

[0223] The reaction conditions are:

[0224] millimeter fluidized bed reactor

[0225] Reaction temperature 430℃

[0226] Reaction pressure 84 kPa

[0227] Catalyst loading: 400 grams

[0228] Catalyst propylene loading (WWH) 0.10 h -1

[0229] Raw material ratio (moles): C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0230] The results are shown in Table 1.

[0231] As can be seen from the comparison between Comparative Example 5 and Example 2, during the preparation of Ce 4+ With an ionic radius of 87.0 pm, which is less than 98 pm, the valence state of rare earth elements plays a significant role in reducing the yield of acrolein impurities and increasing the yield of acrylonitrile.

[0232] As can be seen from the results in Table 1, the catalyst obtained by the preparation method described in this invention achieved good results.

[0233] Table 1

[0234]

[0235] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. An acrylonitrile catalyst comprising a support and an active component, wherein the active component is a metal oxide having the general formula (I) shown below, wherein, A is at least one selected from the group consisting of Li, Na, K, Rb and Cs elements; B is at least one selected from the group consisting of W, Ga, Nb, Mg, Ca, Cr and Co elements; C is a Ce element; a, b, c, d, e, f and x represent the number of atoms of each element; a is 0.01-2.50; b is 0.10-10.00; c is 0.04-0.50; d is 0.01-5.00; e is 1.00-10.00; f is 0.01-5.00; and x is the number of oxygen atoms required to satisfy the valence of other elements. A a B b Fe d Ni e Bi f (MoC c ) 12 O x (I) 2. The acrylonitrile catalyst according to claim 1, wherein the support is at least one selected from the group consisting of silica, alumina, titania and zirconia.

3. The acrylonitrile catalyst according to claim 1 or 2, wherein the a is 0.05-1.50; and / or the b is 1.50-9.00; and / or the c is 0.08-0.30; and / or the d is 0.05-3.00; and / or the e is 1.50-9.00; and / or the f is 0.05-3.

00.

4. The acrylonitrile catalyst according to any one of claims 1-3, wherein the content of the support is 30-70% by weight based on the total weight of the acrylonitrile catalyst.

5. The acrylonitrile catalyst according to any one of claims 1-3, wherein the content of the active component is 30-70% by weight based on the total weight of the acrylonitrile catalyst.

6. The acrylonitrile catalyst according to any one of claims 1-5, wherein the content of the support is 30-70% by weight based on the total weight of the acrylonitrile catalyst; and the content of the active component is 30-70% by weight based on the total weight of the acrylonitrile catalyst.

7. A method for preparing the acrylonitrile catalyst according to any one of claims 1-6, comprising the steps of: (1) dissolving raw materials of A to obtain material i; (2) dissolving raw materials of Mo to obtain material ii; (3) dissolving raw materials of B and Fe, Bi, Ni to obtain material iii; (4) dissolving raw materials of Ce to obtain material iv; (5) mixing the material ii and the material iv under stirring to obtain material v, (6) mixing material i with a support sol, and adding the material iii and the material v under stirring to obtain a catalyst slurry; (7) spray drying the catalyst slurry to obtain a catalyst precursor; and (8) calcining the catalyst precursor in an oxidizing atmosphere to obtain the acrylonitrile catalyst.

8. A method for preparing the acrylonitrile catalyst according to any one of claims 1-7, comprising the steps of: (1) dissolving raw materials of A to obtain material i; (2) dissolving raw materials of Mo to obtain material ii; (3) dissolving raw materials of B and Fe, Bi, Ni to obtain material iii; (4) dissolving raw materials of Ce to obtain material iv; (5) mixing the material ii and the material iv under stirring to obtain material v, (6) mixing material i with a support sol, and adding the material iii and the material v under stirring to obtain a catalyst slurry; (7) spray drying the catalyst slurry to obtain a catalyst precursor; and (8) calcining the catalyst precursor in an oxidizing atmosphere to obtain the acrylonitrile catalyst.

11. Use of the acrylonitrile catalyst according to any one of claims 1-7 or prepared according to the method of any one of claims 8-10 in the production of acrylonitrile by the ammoxidation of propylene. ​ ​ ​ ​ ​ ​ ​ ​ (4) dissolving the raw material of C to obtain a material iv, wherein the C ion in the raw material of C is +3, i.e. C 3+ ; ​ ​ ​ ​ 2. The acrylonitrile catalyst of claim 1, wherein, ​ 3. The acrylonitrile catalyst of claim 1, wherein, ​ 4. The acrylonitrile catalyst of claim 1, wherein, ​ 5. The acrylonitrile catalyst of claim 1, wherein, ​ ​ ​ ​ ​ ​ 6. The acrylonitrile catalyst of claim 1, wherein, C in said step (4) is 3+ 98-102 pm.

7. The acrylonitrile catalyst of claim 1, wherein, C in the step (4) 3+ The ratio of the average ionic radius of Mo 6+ to the ionic radius of Mo is 1.51~1.57:

1. ​ ​ ​ ​ (4) dissolving the raw material of C to obtain a material iv, wherein the C ion in the raw material of C is +3, i.e. C 3+ ; ​ ​ ​ ​ 9. The method of claim 8, wherein, C in said step (4) is 3+ 98-102 pm.

10. The method of claim 8, wherein, C in step (4) 3+ The average ionic radius and the Mo in the molybdenum feedstock 6+ The ratio of their ionic radii is 1.51 to 1.57:

1. ​

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