Catalyst for preparing acrylonitrile, process for its preparation and use thereof

Abstract

The present application provides a catalyst for preparing acrylonitrile, which comprises a carrier and an active component, wherein the active component is a metal oxide having the general formula (I) A a B b C c Fe d Ni e Bi f Mo 12 O x (I). The present application also provides a method for preparing the catalyst for preparing acrylonitrile of the present application. The present application also provides the use of the catalyst for preparing acrylonitrile of the present application or the catalyst for preparing acrylonitrile prepared according to the method of the present application in the preparation of acrylonitrile by propylene ammoxidation. The catalyst for preparing acrylonitrile of the present application still has a high acrylonitrile yield under a high propylene load. The catalyst not only has a high acrylonitrile yield under 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 catalysts for the preparation of acrylonitrile, methods for their preparation, and their applications. Background Technology

[0002] Acrylonitrile is a crucial monomer in three major synthetic processes, primarily used to produce polyacrylonitrile fibers (acrylic fiber). It is also used in the production of ABS resin (acrylonitrile-butadiene-styrene copolymer) and synthetic rubber (acrylonitrile-butadiene copolymer). Acrylic acid, obtained from the hydrolysis of acrylonitrile, is a monomer for synthesizing acrylic resins. Electrolytic hydrogenation of acrylonitrile yields adiponitrile, a raw material for the production of nylon-66, a significant petrochemical product. To obtain highly active and selective fluidized bed catalysts, continuous research and improvements have been made. These improvements largely involve the active composition of the catalyst, focusing on the synergistic effect between active components to enhance activity and selectivity, thereby increasing the single-pass yield of acrylonitrile and improving production load.

[0003] The method of producing acrylonitrile by reacting propylene with molecular oxygen and ammonia is known as the "ammonia oxidation reaction," and this reaction is the commonly used industrial method for producing acrylonitrile worldwide. In this reaction, a composite oxide catalyst is used to achieve a good acrylonitrile yield. For example, industrially catalysts with Mo-Bi-Fe or Fe-Sb as essential components are used, and continuous research is being conducted to improve the metal composition in order to achieve even better acrylonitrile yields (see, for example, Japanese Patent No. 5919870

[0009] and Japanese Patent No. 4954750).

[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] Currently, the industrial production of unsaturated nitriles from olefins via ammoxidation still widely employs fluidized bed ammoxidation. Catalysts, as one of the core technologies of this process, have received significant attention for research and improvement. Currently, there are two main types of catalysts for the industrial ammoxidation of propylene to acrylonitrile: Mo-Bi and Sb-based, with Mo-Bi catalysts dominating, accounting for 95% of the olefin oxidation market. Previous research and exploration have primarily focused on Mo-Bi catalysts. Introducing metal components with variable valence states, such as Fe and Ce, into the catalyst can improve its redox performance and accelerate the recovery of the effective state of the active components.

[0006] 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.

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

[0009] One object of the present invention is to provide a catalyst for the production of acrylonitrile 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.

[0010] The above-mentioned objective of the present invention is achieved through the following technical solution.

[0011] In a first aspect, the present invention provides a catalyst for the preparation of acrylonitrile, comprising a support and an active component, wherein the active component is a metal oxide having the following general formula (I).

[0012] A a B b C c Fe d Ni e Bi f Mo 12 O x (I)

[0013] in,

[0014] A is selected from at least one of the elements Li, Na, K, Rb, and Cs;

[0015] B is selected from at least one of the elements W, Ga, Nb, Sn, Hf, Zr, Mg, Cu, Zn, and Co;

[0016] C is selected from at least one of the elements Ce, La, Nd, and Pr;

[0017] a, b, c, d, e, f, and x represent the number of atoms of each element;

[0018] a ranges from 0.01 to 2.50;

[0019] b is 0.10 to 10.00;

[0020] c ranges from 0.01 to 5.00;

[0021] d ranges from 0.01 to 5.00;

[0022] e ranges from 1.00 to 10.00;

[0023] f ranges from 0.01 to 5.00;

[0024] x represents the number of oxygen atoms required to satisfy the valence of other elements.

[0025] The inventors of this application unexpectedly discovered that the catalyst of this invention exhibits a high acrylonitrile yield under high propylene loading. Not wishing to be bound by theory, it is believed that the high acrylonitrile yield of the catalyst of this invention under high propylene loading may be attributed to the rational combination of elements, fully utilizing the "synergistic effect" between elements, particularly the appropriately sized ionic radii of element B and Mo. 6+The more uniform and stable composition of the catalyst moderates structural distortion and reduces the loss of molybdenum from the active component. By introducing alkali metal elements, the surface pH of the catalyst is adjusted, enabling the catalyst to effectively adsorb reactants at lower temperatures, ensuring high acrylonitrile yield and propylene conversion under low-temperature, high-load conditions. Furthermore, this embodiment introduces at least one of Ce, La, Nd, and Pr, which not only reduces the amount of reaction byproducts but also provides the catalyst with good acrylonitrile yield, selectivity, and stability under higher loads.

[0026] Preferably, in the catalyst for preparing acrylonitrile according to the present invention, the content of the support is 30-70% by weight, based on the total weight of the catalyst.

[0027] Preferably, in the catalyst for preparing acrylonitrile according to the present invention, the content of the active component is 30-70% by weight, based on the total weight of the catalyst.

[0028] Preferably, in the catalyst for preparing acrylonitrile according to the present invention, the support is selected from at least one of silica, alumina, titanium dioxide and zirconium oxide.

[0029] Preferably, in the catalyst for preparing acrylonitrile according to the present invention, a is 0.05 to 1.50.

[0030] Preferably, in the catalyst for preparing acrylonitrile according to the present invention, b is 1.50 to 9.00.

[0031] Preferably, in the catalyst for preparing acrylonitrile according to the present invention, c is 0.05 to 3.50.

[0032] Preferably, in the catalyst for preparing acrylonitrile according to the present invention, d is 0.05 to 3.00.

[0033] Preferably, in the catalyst for preparing acrylonitrile according to the present invention, e is 1.50 to 9.00.

[0034] Preferably, in the catalyst for preparing acrylonitrile according to the present invention, f is 0.05 to 3.00.

[0035] Preferably, in the catalyst for preparing acrylonitrile according to the present invention, for the raw material used to form the active component, in the raw material of B, the ionic radius of B is 62-74.5 pm.

[0036] Preferably, in the catalyst for preparing acrylonitrile according to the present invention, for the raw materials used to form the active component, in the raw materials of B and Mo, the average ionic radius of B and Mo are... 6+The ratio of their ionic radii is 0.955 to 1.145:1.

[0037] In a second aspect, the present invention provides a method for preparing the catalyst for preparing acrylonitrile of the present invention, comprising the following steps:

[0038] (1) After dissolving raw material A, material i is obtained;

[0039] (2) The raw material of molybdenum is dissolved to obtain material ii;

[0040] (3) After dissolving the raw materials of B and Fe, Bi and Ni, material iii is obtained;

[0041] (4) Dissolve the raw material of C to obtain material iv;

[0042] (5) Mix material i with carrier sol, and add material ii and material iii while stirring, and then add material iv to obtain catalyst slurry;

[0043] (6) The catalyst slurry is spray-dried to obtain a catalyst precursor;

[0044] (7) The catalyst precursor is calcined in an oxidizing atmosphere to obtain a catalyst for the preparation of acrylonitrile.

[0045] Preferably, in the method described in this invention, the ionic radius of B in the raw material of B is 62-74.5 pm.

[0046] Preferably, in the method described in this invention, in the raw materials of B and Mo, the average ionic radius of B and Mo are... 6+ The ratio of their ionic radii is 0.955 to 1.145:1.

[0047] In the method of this invention, the ionic radius of B is not particularly limited and can be 62-74.5 pm. When the ionic radius of B is lower than 62 pm, unstable molybdates are formed, which is detrimental to the stability of molybdenum. Similarly, when the ionic radius of B is higher than 74.5 pm, unstable molybdates are formed, which is also detrimental to the stability of molybdenum, making it prone to loss and resulting in poor catalytic performance.

[0048] In the method of the present invention, the average ionic radius of B and Mo are compared. 6+ The ratio of ionic radii is not particularly limited and can be 0.955 to 1.145:1. When the average ionic radius of B is... 6+ When the ratio of the ionic radii of B to Mo is less than 0.955, unstable molybdates are formed, which is detrimental to the stability of molybdenum; when the average ionic radius of B is less than that of Mo... 6+When the ratio of ionic radii is greater than 1.145, unstable molybdates are formed, which is also detrimental to the stability of molybdenum and makes it easy to be lost, resulting in poor catalytic performance.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] As a specific embodiment of the present invention, the cerium, lanthanum, 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.

[0053] As a specific embodiment of the present invention, the tungsten, gallium, niobium, tin, hafnium, gypsum, magnesium, copper, zinc and cobalt in the catalyst can be in oxide form, or any compound that can generate oxides during calcination can be used, with water-soluble salts being more preferred.

[0054] Thirdly, the present invention provides the application of the catalyst for preparing acrylonitrile of the present invention or the catalyst for preparing acrylonitrile prepared according to the method of the present invention in the ammoxidation of propylene to acrylonitrile.

[0055] The present invention has the following beneficial effects:

[0056] The catalyst for acrylonitrile production of the present invention 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, resulting in a high acrylonitrile recovery rate in the plant, thereby improving the plant's production efficiency and economic benefits. Detailed Implementation

[0057] The present invention will be further described below with reference to specific embodiments, but this does not constitute any limitation on the present invention.

[0058] Example 1

[0059] 1. Catalyst Preparation

[0060] Add 15 g of water to 8.42 g of potassium hydroxide and heat to dissolve, obtaining material i; add 330.8 g of ammonium heptamolybdate (NH4)6Mo7O 24 • Dissolve 4H2O in 300g of hot water at 80℃ to obtain material ii; Mix 113.0g of bismuth nitrate Bi(NO3)3·5H2O, 159.3g of magnesium nitrate Mg(NO3)2·6H2O, 251.0g of nickel nitrate Ni(NO3)2·6H2O, and 113.6g of iron nitrate Fe(NO3)3·9H2O, add 100g of water, heat to dissolve, and obtain material iii; Add 168.7g of neodymium nitrate Nd(NO3)3·6H2O to 100g of water, heat to dissolve, and obtain material iv.

[0061] Material i was mixed with 1250 g of silica sol with a weight concentration of 40%. While stirring, materials ii and iii were added simultaneously, followed by material iv to obtain a catalyst 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:

[0062] 50% K 0.80 Mg 4.00 Nd 2.50 Fe 1.80 Ni 5.50 Bi 1.50 Mo 12.0 O x +50% SiO2

[0063] 2. Catalyst Evaluation

[0064] The reaction conditions are:

[0065] millimeter fluidized bed reactor

[0066] Reaction temperature 430℃

[0067] Reaction pressure 84 kPa

[0068] Catalyst loading: 400 grams

[0069] Catalyst propylene loading (WWH) 0.10 h -1

[0070] Raw material ratio (moles): C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0071] The results are shown in Table 1.

[0072] Example 2

[0073] 1. Catalyst Preparation

[0074] Add 15 grams of water to 7.64 grams of potassium hydroxide and heat to dissolve, obtaining material i; add 300.2 grams of ammonium heptamolybdate (NH4)6Mo7O 24 • Dissolve 4H2O in 300g of hot water at 80℃ to obtain material ii; Mix 102.6g of bismuth nitrate Bi(NO3)3·5H2O, 242.1g of zirconium nitrate Zr(NO3)4·5H2O, 227.8g of nickel nitrate Ni(NO3)2·6H2O, and 103.6g of ferric nitrate Fe(NO3)3·9H2O, add 100g of water, heat to dissolve, and obtain material iii; Add 153.1g of neodymium nitrate Nd(NO3)3·6H2O to 100g of water, heat to dissolve, and obtain material iv.

[0075] Material i was mixed with 1250 g of silica sol with a weight concentration of 40%. While stirring, materials ii and iii were added simultaneously, followed by material iv to obtain a catalyst 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:

[0076] 50% K 0.80 Zr 4.00 Nd 2.50 Fe 1.80 Ni 5.50 Bi 1.50 Mo 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 3

[0087] 1. Catalyst Preparation

[0088] Add 15 g of water to 8.01 g of potassium hydroxide and heat to dissolve, obtaining material i; add 314.9 g of ammonium heptamolybdate (NH4)6Mo7O 24 • Dissolve 4H2O in 300g of hot water at 80℃ to obtain material ii; Mix 107.6g of bismuth nitrate Bi(NO3)3·5H2O, 176.0g of zinc nitrate Zn(NO3)2·6H2O, 239.0g of nickel nitrate Ni(NO3)2·6H2O, and 108.6g of ferric nitrate Fe(NO3)3·9H2O, add 100g of water, heat to dissolve, and obtain material iii; Add 160.6g of neodymium nitrate Nd(NO3)3·6H2O to 100g of water, heat to dissolve, and obtain material iv.

[0089] Material i was mixed with 1250 g of silica sol with a weight concentration of 40%. While stirring, materials ii and iii were added simultaneously, followed by material iv to obtain a catalyst 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:

[0090] 50% K 0.80 Zn 4.00 Nd 2.50 Fe 1.80 Ni 5.50 Bi 1.50 Mo 12.0 O x +50% SiO2

[0091] 2. The reaction conditions for catalyst evaluation are as follows:

[0092] millimeter fluidized bed reactor

[0093] Reaction temperature 430℃

[0094] Reaction pressure 84 kPa

[0095] Catalyst loading 400 grams

[0096] Catalyst propylene loading (WWH) 0.10 h -1

[0097] Raw material ratio (moles): C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0098] The results are shown in Table 1.

[0099] Example 4

[0100] 1. Catalyst Preparation

[0101] Add 15 grams of water to 7.58 grams of potassium hydroxide and heat to dissolve, obtaining material i; add 297.8 grams of ammonium heptamolybdate (NH4)6Mo7O 24 • Dissolve 4H2O in 300g of hot water at 80℃ to obtain material ii; Mix 101.8g of bismuth nitrate Bi(NO3)3·5H2O, 173.4g of niobium oxalate Nb2(C2O4)5, 226.0g of nickel nitrate Ni(NO3)2·6H2O, and 102.8g of ferric nitrate Fe(NO3)3·9H2O, add 100g of water, heat to dissolve, and obtain material iii; Add 151.8g of cerium nitrate Ce(NO3)3·6H2O to 100g of water, heat to dissolve, and obtain material iv.

[0102] Material i was mixed with 1250 g of silica sol with a weight concentration of 40%. While stirring, materials ii and iii were added simultaneously, followed by material iv to obtain a catalyst 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:

[0103] 50% K 0.80 Nb 4.00 Ce 2.50 Fe 1.80 Ni 5.50 Bi 1.50 Mo 12.0 O x +50% SiO2

[0104] 2. The reaction conditions for catalyst evaluation are as follows:

[0105] millimeter fluidized bed reactor

[0106] Reaction temperature 430℃

[0107] Reaction pressure 84 kPa

[0108] Catalyst loading 400 grams

[0109] Catalyst propylene loading (WWH) 0.10 h -1

[0110] Raw material ratio (moles): C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0111] The results are shown in Table 1.

[0112] Example 5

[0113] 1. Catalyst Preparation

[0114] Add 15 grams of water to 7.99 grams of potassium hydroxide and heat to dissolve, obtaining material i; add 313.9 grams of ammonium heptamolybdate (NH4)6Mo7O 24 • Dissolve 4H2O in 300g of hot water at 80℃ to obtain material ii; Mix 107.3g of bismuth nitrate Bi(NO3)3·5H2O, 91.4g of niobium oxalate Nb2(C2O4)5, 75.6g of magnesium nitrate Mg(NO3)2·6H2O, 238.2g of nickel nitrate Ni(NO3)2·6H2O, and 108.3g of ferric nitrate Fe(NO3)3·9H2O, add 100g of water, heat to dissolve, and obtain material iii; Add 160.0g of cerium nitrate Ce(NO3)3·6H2O to 100g of water, heat to dissolve, and obtain material iv.

[0115] Material i was mixed with 1250 g of silica sol with a weight concentration of 40%. While stirring, materials ii and iii were added simultaneously, followed by material iv to obtain a catalyst 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:

[0116] 50% K 0.80 Mg 2.0 Nb 2.00 Ce 2.50 Fe 1.80 Ni 5.50 Bi 1.50 Mo 12.0 O x +50% SiO2

[0117] 2. The reaction conditions for catalyst evaluation are as follows:

[0118] millimeter fluidized bed reactor

[0119] Reaction temperature 430℃

[0120] Reaction pressure 84 kPa

[0121] Catalyst loading: 400 grams

[0122] Catalyst propylene loading (WWH) 0.10 h -1

[0123] Raw material ratio (moles): C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0124] The results are shown in Table 1.

[0125] Example 6

[0126] 1. Catalyst Preparation

[0127] Add 15 grams of water to 7.77 grams of potassium hydroxide and heat to dissolve, obtaining material i; add 305.1 grams of ammonium heptamolybdate (NH4)6Mo7O 24 • 4H2O was dissolved in 300g of hot water at 80℃ to obtain material ii; 104.3g of bismuth nitrate Bi(NO3)3·5H2O, 44.4g of niobium oxalate Nb2(C2O4)5, and 35.7g of ammonium metatungstate (NH4)6H2W were added. 12 O 40 73.5 g of magnesium nitrate Mg(NO3)2·6H2O, 231.5 g of nickel nitrate Ni(NO3)2·6H2O, and 105.3 g of ferric nitrate Fe(NO3)3·9H2O were mixed, 100 g of water was added, and the mixture was heated to dissolve, which was obtained as material iii; 155.6 g of cerium nitrate Ce(NO3)3·6H2O was added to 100 g of water, and the mixture was heated to dissolve, which was obtained as material iv.

[0128] Material i was mixed with 1250 g of silica sol with a weight concentration of 40%. While stirring, materials ii and iii were added simultaneously, followed by material iv to obtain a catalyst 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:

[0129] 50% K 0.80 Mg 2.0 W 1.00 Nb 1.00 Ce 2.50 Fe 1.80 Ni 5.50 Bi 1.50 Mo12.0 O x +50% SiO2

[0130] 2. Catalyst Evaluation

[0131] The reaction conditions are:

[0132] millimeter fluidized bed reactor

[0133] Reaction temperature 430℃

[0134] Reaction pressure 84 kPa

[0135] Catalyst loading: 400 grams

[0136] Catalyst propylene loading (WWH) 0.10 h -1

[0137] Raw material ratio (moles): C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0138] The results are shown in Table 1.

[0139] A comparison of Examples 5-6 with Examples 1-4 shows that the combination of element B has a synergistic effect in improving the yield of acrylonitrile.

[0140] Comparative Example 1

[0141] 1. Catalyst Preparation

[0142] Add 15 g of water to 7.93 g of potassium hydroxide and heat to dissolve, obtaining material i; add 311.4 g of ammonium heptamolybdate (NH4)6Mo7O 24 • Dissolve 4H2O in 300g of hot water at 80℃ to obtain material ii; Mix 106.4g of bismuth nitrate Bi(NO3)3·5H2O, 68.1g of ammonium metavanadate NH4VO3, 236.3g of nickel nitrate Ni(NO3)2·6H2O, and 107.4g of ferric nitrate Fe(NO3)3·9H2O, add 100g of water, heat to dissolve, and obtain material iii; Add 158.8g of neodymium nitrate Nd(NO3)3·6H2O to 100g of water, heat to dissolve, and obtain material iv.

[0143] Material i was mixed with 1250 g of silica sol with a weight concentration of 40%. While stirring, materials ii and iii were added simultaneously, followed by material iv to obtain a catalyst 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, the slurry was calcined at 585°C for 2.0 hours in a rotary calcining furnace with an inner diameter of 89 mm and a length of 1700 mm (φ89×1700 mm) to obtain a catalyst composition, by mass fraction:

[0144] 50% K 0.80 V 4.00 Nd 2.50 Fe 1.80 Ni 5.50 Bi 1.50 Mo 12.0 O x +50% SiO2

[0145] 2. The reaction conditions for catalyst evaluation are as follows:

[0146] millimeter fluidized bed reactor

[0147] Reaction temperature 430℃

[0148] Reaction pressure 84 kPa

[0149] Catalyst loading: 400 grams

[0150] Catalyst propylene loading (WWH) 0.10 h -1

[0151] Raw material ratio (moles): C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0152] The results are shown in Table 1.

[0153] Comparative Example 2

[0154] 1. Catalyst Preparation

[0155] Add 15 grams of water to 7.45 grams of potassium hydroxide and heat to dissolve, obtaining material i; add 292.8 grams of ammonium heptamolybdate (NH4)6Mo7O 24• Dissolve 4H2O in 300g of hot water at 80℃ to obtain material ii; Mix 100.1g of bismuth nitrate Bi(NO3)3·5H2O, 81.0g of antimony trioxide Sb2O3, 222.2g of nickel nitrate Ni(NO3)2·6H2O, and 101.0g of ferric nitrate Fe(NO3)3·9H2O, add 100g of water, heat to dissolve, and obtain material iii; Add 149.3g of neodymium nitrate Nd(NO3)3·6H2O to 100g of water, heat to dissolve, and obtain material iv.

[0156] Material i was mixed with 1250 g of silica sol with a weight concentration of 40%. While stirring, materials ii and iii were added simultaneously, followed by material iv to obtain a catalyst 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, the slurry was calcined at 585°C for 2.0 hours in a rotary calcining furnace with an inner diameter of 89 mm and a length of 1700 mm (φ89×1700 mm) to obtain a catalyst composition, by mass fraction:

[0157] 50% K 0.80 Sb 4.00 Nd 2.50 Fe 1.80 Ni 5.50 Bi 1.50 Mo 12.0 O x +50% SiO2

[0158] 2. Catalyst Evaluation

[0159] The reaction conditions are:

[0160] millimeter fluidized bed reactor

[0161] Reaction temperature 430℃

[0162] Reaction pressure 84 kPa

[0163] Catalyst loading: 400 grams

[0164] Catalyst propylene loading (WWH) 0.10 h -1

[0165] Raw material ratio (moles): C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0166] The results are shown in Table 1.

[0167] As can be seen from the comparison between Comparative Examples 1-2 and Examples 1-4, V 5+ The ionic radius of Sb is 59 pm, which is less than 62 pm. 3+The ionic radius is 76 pm, which is greater than 74.5 pm. The size of the ionic radius plays a key role in reducing the yield of acrolein impurities and increasing the yield of acrylonitrile.

[0168] Comparative Example 3

[0169] 1. Catalyst Preparation

[0170] Add 15 g of water to 8.42 g of potassium hydroxide and heat to dissolve, obtaining material i; add 330.8 g of ammonium heptamolybdate (NH4)6Mo7O 24 • Dissolve 4H2O in 300g of hot water at 80℃ to obtain material ii; Mix 113.0g of bismuth nitrate Bi(NO3)3·5H2O, 159.3g of magnesium nitrate Mg(NO3)2·6H2O, 251.0g of nickel nitrate Ni(NO3)2·6H2O, and 113.6g of iron nitrate Fe(NO3)3·9H2O, add 100g of water, heat to dissolve, and obtain material iii; Add 168.7g of neodymium nitrate Nd(NO3)3·6H2O to 100g of water, heat to dissolve, and obtain material iv.

[0171] Material i was mixed with 1250 g of silica sol with a weight concentration of 40%. Then, materials ii, iii, and iv were added sequentially under stirring to obtain a catalyst 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, the slurry was calcined at 585°C for 2.0 hours in a rotary calcining furnace with an inner diameter of 89 mm and a length of 1700 mm (φ89×1700 mm) to obtain a catalyst with the following composition by mass fraction:

[0172] 50% K 0.80 Mg 4.00 Nd 2.50 Fe 1.80 Ni 5.50 Bi 1.50 Mo 12.0 O x +50% SiO2

[0173] 2. Catalyst Evaluation

[0174] The reaction conditions are:

[0175] millimeter fluidized bed reactor

[0176] Reaction temperature 430℃

[0177] Reaction pressure 84 kPa

[0178] Catalyst loading: 400 grams

[0179] Catalyst propylene loading (WWH) 0.10 h -1

[0180] Raw material ratio (moles): C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0181] The results are shown in Table 1.

[0182] The comparison between Comparative Example 3 and Example 1 shows that the simultaneous addition and uniform mixing of alkaline earth metal raw materials such as Mo and B has a significant effect on reducing the yield of acrolein impurities and increasing the yield of acrylonitrile.

[0183] Comparative Example 4

[0184] 1. Catalyst Preparation

[0185] Add 15 g of water to 7.90 g of potassium hydroxide and heat to dissolve, obtaining material i; add 310.4 g of ammonium heptamolybdate (NH4)6Mo7O 24 • Dissolve 4H2O in 300g of hot water at 80℃ to obtain material ii; Mix 106.1g of bismuth nitrate Bi(NO3)3·5H2O, 54.1g of gallium trioxide Ga2O3, 235.6g of nickel nitrate Ni(NO3)2·6H2O, and 107.1g of ferric nitrate Fe(NO3)3·9H2O, add 100g of water, heat to dissolve, and obtain material iii; Add 158.3g of neodymium nitrate Nd(NO3)3·6H2O to 100g of water, heat to dissolve, and obtain material iv.

[0186] Material i was mixed with 1250 g of silica sol with a weight concentration of 40%. While stirring, materials ii and iii were added simultaneously, followed by material iv to obtain a catalyst 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, the slurry was calcined at 585°C for 2.0 hours in a rotary calcining furnace with an inner diameter of 89 mm and a length of 1700 mm (φ89×1700 mm) to obtain a catalyst composition, by mass fraction:

[0187] 50% K 0.80 Ga 4.00 Nd 2.50 Fe 1.80 Ni 5.50 Bi 1.50 Mo 12.0 O x +50% SiO2

[0188] 2. The reaction conditions for catalyst evaluation are as follows:

[0189] millimeter fluidized bed reactor

[0190] Reaction temperature 430℃

[0191] Reaction pressure 84 kPa

[0192] Catalyst loading: 400 grams

[0193] Catalyst propylene loading (WWH) 0.10 h -1

[0194] Raw material ratio (moles): C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0195] The results are shown in Table 1.

[0196] Comparative Example 5

[0197] 1. Catalyst Preparation

[0198] Add 15 g of water to 8.13 g of potassium hydroxide and heat to dissolve, obtaining material i; add 319.5 g of ammonium heptamolybdate (NH4)6Mo7O 24 • Dissolve 4H2O in 300g of hot water at 80℃ to obtain material ii; Mix 109.2g of bismuth nitrate Bi(NO3)3·5H2O, 201.6g of scandium nitrate Sc(NO3)3·6H2O, 242.5g of nickel nitrate Ni(NO3)2·6H2O, and 110.3g of ferric nitrate Fe(NO3)3·9H2O, add 100g of water, heat to dissolve, and obtain material iii; Add 163.0g of neodymium nitrate Nd(NO3)3·6H2O to 100g of water, heat to dissolve, and obtain material iv.

[0199] Material i was mixed with 1250 g of silica sol with a weight concentration of 40%. While stirring, materials ii and iii were added simultaneously, followed by material iv to obtain a catalyst 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, the slurry was calcined at 585°C for 2.0 hours in a rotary calcining furnace with an inner diameter of 89 mm and a length of 1700 mm (φ89×1700 mm) to obtain a catalyst composition, by mass fraction:

[0200] 50% K 0.80 Sc 4.00 Nd 2.50 Fe 1.80 Ni 5.50 Bi 1.50 Mo 12.0 O x +50% SiO2

[0201] 2. Catalyst Evaluation

[0202] The reaction conditions are:

[0203] millimeter fluidized bed reactor

[0204] Reaction temperature 430℃

[0205] Reaction pressure 84 kPa

[0206] Catalyst loading: 400 grams

[0207] Catalyst propylene loading (WWH) 0.10 h -1

[0208] Raw material ratio (moles): C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0209] The results are shown in Table 1.

[0210] As can be seen from the comparison between Comparative Examples 4-5 and Examples 1-4, the ionic radius of B is similar to that of Mo. 6+ The radius ratio plays a crucial role in reducing the yield of acrolein impurities and increasing the yield of acrylonitrile.

[0211] Table 1

[0212]

[0213] 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. A catalyst for the preparation of acrylonitrile, comprising a support and an active component, wherein the active component is a metal oxide having the following general formula (I), A a B b C c Want d In e Like f Know 12 SHE x (I) in, A is selected from K; B is selected from Mg; C is selected from Nd; a, b, c, d, e, f, and x represent the number of atoms of each element; a ranges from 0.01 to 2.50; b is 0.10~10.00; c ranges from 0.01 to 5.00; d ranges from 0.01 to 5.00; e is 1.00~10.00; f ranges from 0.01 to 5.00; x represents the number of oxygen atoms required to satisfy the valence of other elements. A method for preparing a catalyst for acrylonitrile includes the following steps: (1) After dissolving the raw material of A, material i is obtained; (2) The raw material of molybdenum is dissolved to obtain material ii; (3) After dissolving the raw materials of B and Fe, Bi and Ni, material iii is obtained; (4) Dissolve the raw material of C to obtain material iv; (5) Mix material i with carrier sol, and add material ii and material iii while stirring, and then add material iv to obtain catalyst slurry; (6) The catalyst slurry is spray-dried to obtain a catalyst precursor; (7) The catalyst precursor is calcined in an oxidizing atmosphere to obtain a catalyst for the preparation of acrylonitrile.

2. The catalyst for preparing acrylonitrile according to claim 1, wherein, The content of the support is 30-70% by weight based on the total weight of the catalyst.

3. The catalyst for preparing acrylonitrile according to claim 1, wherein, The content of the active component is 30-70% by weight based on the total weight of the catalyst.

4. The catalyst for preparing acrylonitrile according to claim 1, wherein, The carrier is selected from at least one of silicon dioxide, aluminum oxide, titanium oxide, and zirconium oxide.

5. The catalyst for preparing acrylonitrile according to claim 1, wherein, The value of a is 0.05 to 1.50; and / or The value of b is 1.50 to 9.00; and / or The c is 0.05 to 3.50; and / or The value of d is 0.05 to 3.00; and / or The value of e is 1.50 to 9.00; and / or The value of f is 0.05 to 3.

00.

6. A method for preparing a catalyst for preparing acrylonitrile according to any one of claims 1-5, comprising the following steps: (1) After dissolving the raw material of A, material i is obtained; (2) The raw material of molybdenum is dissolved to obtain material ii; (3) After dissolving the raw materials of B and Fe, Bi and Ni, material iii is obtained; (4) Dissolve the raw material of C to obtain material iv; (5) Mix material i with carrier sol, and add material ii and material iii while stirring, and then add material iv to obtain catalyst slurry; (6) The catalyst slurry is spray-dried to obtain a catalyst precursor; (7) The catalyst precursor is calcined in an oxidizing atmosphere to obtain a catalyst for the preparation of acrylonitrile.

7. The use of the catalyst for preparing acrylonitrile according to any one of claims 1-5 or the catalyst for preparing acrylonitrile prepared according to the method of claim 6 in the ammoxidation of propylene to acrylonitrile.

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