Molybdenum-bismuth-iron catalyst, preparation method and application thereof, and propylene ammoxidation method

Abstract

The invention relates to the field of catalysts, in particular to a molybdenum-bismuth-iron catalyst, a preparation method and application thereof and a propylene ammoxidation method. The catalyst comprises a carrier and an active component, the active component has a composition as shown in a formula AaBbCcFedNieBifMo12.5 Ox, in the formula, A is at least one of alkali metal elements, B is at least one of alkaline earth metal elements, transition metal elements and IIIA family metal elements, and C is at least one of lanthanide series metal elements; the value range of a is from 0.01 to 2.50; the value range of b is 0.10 to 10.00; the value range of c is from 0.01 to 5.00; the value range of d is from 0.01 to 5.00; the value range of e is from 1.00 to 10.00; the value range of f is from 0.01 to 5.00; x is the total number of oxygen atoms required for meeting the valence of each element in the catalyst; in a laser Raman spectrogram of the catalyst, the strength ratio at 785 + / -2 cm <-1 > to 956 + / -2 cm <-1 > is 0.55-0.80. The catalyst is excellent in stability, and the production efficiency and economic benefits of the device can be improved.

Description

Technical Field

[0001] The invention relates to the field of catalysts, and in particular to a molybdenum-bismuth-iron catalyst and a preparation method and application thereof, and a method for ammoxidation of propylene. Background Art

[0002] Acrylonitrile is an important organic chemical raw material, which is produced by the ammoxidation reaction of propylene. In order to obtain a fluidized bed catalyst with high activity and selectivity, people have made a series of improvements through continuous exploration. Most of these improvements involve the active composition of the catalyst, focusing on the matching between the active components of the catalyst to improve the activity and selectivity of the catalyst, thereby achieving an increase in the single-pass yield of acrylonitrile and an increase in production load.

[0003] After more than 50 years of development, the ammonia oxidation method for producing acrylonitrile still has a gap in demand for acrylonitrile in recent years. The main development trend of acrylonitrile production is to build new large-scale devices to achieve large-scale production, so as to further reduce raw material consumption and production energy consumption and increase production capacity. The production capacity of new domestic acrylonitrile devices has increased significantly. After completion, the production capacity of the factory will be close to the balance of market demand. Therefore, the competition among acrylonitrile factories in the future will not only lie in the economic benefits of acrylonitrile production efficiency, but also in the competition of clean production that focuses on environmental protection, ensuring the long-term stable operation of acrylonitrile catalysts, and reducing maintenance cycles, thereby improving the overall economic benefits of the device.

[0004] When the original acrylonitrile unit is expanded, the catalyst loading amount is required not to be too much. For this reason, the replaced catalyst is required to maintain a high acrylonitrile yield under a higher propylene load. When the reactor size and production capacity are determined, the amount of catalyst loaded in the reactor is related to the load that the catalyst can withstand, namely WWH. It is defined as the number of tons of propylene that can be processed per ton of catalyst per hour. When the reactor feed rate increases, if the catalyst load remains unchanged, the catalyst loading amount must also increase accordingly. However, the height of the cooling water pipe in the original design of the fluidized bed reactor is not enough, so the fluidization height of the catalyst in the reactor may exceed the height of the cooling water pipe. In addition, due to the increase in the reactor feed rate, the operating line speed is also significantly increased. The combined effect of these two changes may cause the reactor dilute phase temperature to rise, resulting in an increase in carbon dioxide generation and a decrease in acrylonitrile selectivity. Therefore, a catalyst with a higher WWH can prevent the above problems.

[0005] However, the prior art does not involve a catalyst capable of producing acrylonitrile at a higher propylene load and a higher reaction pressure. Summary of the invention

[0006] The purpose of the present invention is to overcome the problem that the ammoxidation catalyst in the prior art cannot produce acrylonitrile under high propylene load and high reaction pressure, and to provide a molybdenum-bismuth-iron catalyst and its preparation method and application and a method for ammoxidation of propylene. The catalyst can produce nitrile compounds under high olefin load and high reaction pressure with high yield and good stability.

[0007] In order to achieve the above object, the present invention provides a molybdenum-bismuth-iron catalyst in a first aspect. The catalyst comprises a carrier and an active component. The active component has a formula A a B b C c Fe d Ni e Bi f Mo 12.5 O x The composition is shown in the formula, wherein A is at least one of alkali metal elements, B is at least one of alkaline earth metal elements, transition metal elements and Group IIIA metal elements, and C is at least one of lanthanide metal elements; a is in the range of 0.01-2.50; b is in the range of 0.10-10.00; c is in the range of 0.01-5.00; d is in the range of 0.01-5.00; e is in the range of 1.00-10.00; f is in the range of 0.01-5.00; x is the total number of oxygen atoms required to satisfy the valence of each element in the catalyst; in the laser Raman spectrum of the catalyst, at 785±2cm -1 and 956±2cm -1 The intensity ratio at is 0.55-0.80.

[0008] The second aspect of the present invention provides a method for preparing the molybdenum-bismuth-iron catalyst, the preparation method comprising:

[0009] (1) Preparing a precursor containing element A and a carrier, wherein free [H + ] concentration is 10 -10.5 -10 -8.4 mol / L; the particle size of the carrier in the precursor is 5-15nm, and the specific surface area is 150-650m 2 / g;

[0010] (2) The precursor is mixed with a solution containing Mo, C, B, Fe, Bi, and Ni to obtain a slurry, which is then heat treated, dried, and calcined.

[0011] The third aspect of the present invention provides a use of the catalyst described in the first aspect of the present invention in an olefin ammoxidation reaction.

[0012] The fourth aspect of the present invention provides a method for ammoxidation of propylene, comprising: contacting and reacting a propylene raw material, an ammonia raw material and an oxygen raw material under catalyst conditions; wherein the catalyst is the catalyst described in the first aspect of the invention.

[0013] Through the above technical solution, the present invention has the following advantages:

[0014] The catalyst having the composition of the present invention has a specific crystal phase (characteristics of the laser Raman peak), not only has a higher yield of nitrile compounds (especially acrylonitrile) under a higher olefin (especially propylene) load, but also has excellent catalyst stability, thereby improving the production efficiency and economic benefits of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a laser Raman comparison diagram of the catalyst prepared in Example 1, the catalyst prepared in Comparative Example 1, and the catalyst prepared in Comparative Example 2;

[0016] Figure 2 This is the laser Raman image of the catalyst prepared in Example 2. DETAILED DESCRIPTION

[0017] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0018] The present invention provides a molybdenum-bismuth-iron catalyst, which comprises a carrier and an active component, wherein the active component has a formula A a B b C c Fe d Ni e Bi f Mo 12.5 O x The composition is shown in the formula, wherein A is at least one of alkali metal elements, B is at least one of alkaline earth metal elements, transition metal elements and Group IIIA metal elements, and C is at least one of lanthanide metal elements; a is in the range of 0.01-2.50; b is in the range of 0.10-10.00; c is in the range of 0.01-5.00; d is in the range of 0.01-5.00; e is in the range of 1.00-10.00; f is in the range of 0.01-5.00; x is the total number of oxygen atoms required to satisfy the valence of each element in the catalyst; in the laser Raman spectrum of the catalyst, at 785±2cm -1 and 956±2cm-1 The intensity ratio at is 0.55-0.80, for example, it can be 0.55, 0.57, 0.60, 0.65, 0.70, 0.75, 0.78, 0.80, and preferably 0.57-0.78.

[0019] The catalyst having the characteristics of the present invention not only has a higher yield of nitrile compounds (especially acrylonitrile) under a higher olefin (especially propylene) load, but also has a specific crystal phase and excellent stability, thereby improving the production efficiency and economic benefits of the device.

[0020] According to a preferred embodiment of the present invention, the formula A a B b C c Fe d Ni e Bi f Mo 12.5 O x In the above, A is selected from at least one of Li, Na, K, Rb and Cs, and preferably at least one of K, Rb and Cs.

[0021] According to a preferred embodiment of the present invention, the formula A a B b C c Fe d Ni e Bi f Mo 12.5 O x In the embodiment, B is selected from at least one of W, Ga, Nb, Mg, Ca, Cr and Co, and preferably at least one of W, Mg, Ca, Cr and Co.

[0022] According to a preferred embodiment of the present invention, the formula A a B b C c Fe d Ni e Bi f Mo 12.5 O x In the embodiment, C is selected from at least one of La, Ce, Nd and Pr, and preferably at least one of La, Ce and Nd.

[0023] According to a preferred embodiment of the present invention, the formula A a B b C c Fe d Ni e Bi f Mo 12.5 O xIn the equation, the value range of a is 0.05-1.50; the value range of b is 1.50-9.00; the value range of c is 0.05-3.50; the value range of d is 0.05-3.00; the value range of e is 1.50-9.00; and the value range of f is 0.05-3.00.

[0024] In the present invention, there is no special requirement for the content of each component of the catalyst. According to a preferred embodiment of the present invention, based on the total mass of the catalyst, the catalyst comprises: 30-70% of the carrier; 30-70% of the active component. The present invention takes 50% of the carrier; 50% of the active component as an example to illustrate the advantages of the present invention.

[0025] In the present invention, the carrier can be a conventional choice in the art. According to a preferred embodiment of the present invention, the carrier is selected from at least one of silicon dioxide, aluminum oxide, titanium oxide and zirconium oxide. The present invention takes silicon dioxide as an example to illustrate the advantages of the present invention.

[0026] The present invention provides a method for preparing a molybdenum-bismuth-iron catalyst, the preparation method comprising:

[0027] (1) Preparing a precursor containing element A and a carrier, wherein free [H + ] concentration is 10 -10.5 -10 -8.4 mol / L; the particle size of the carrier in the precursor is 5-15nm, and the specific surface area is 150-650m 2 / g;

[0028] (2) The precursor is mixed with a solution containing Mo, C, B, Fe, Bi, and Ni to obtain a slurry, which is then heat treated, dried, and calcined.

[0029] The molybdenum-bismuth-iron catalyst prepared by the method of the present invention not only has a higher yield of nitrile compounds (especially acrylonitrile) under a higher olefin (especially propylene) load, but also has a specific crystal phase and excellent stability, thereby improving the production efficiency and economic benefits of the device.

[0030] According to a preferred embodiment of the present invention, in step (1), the step of preparing the precursor comprises: dissolving source A to obtain solution I, and mixing solution I, a pH adjuster and a carrier source to obtain a precursor.

[0031] According to a preferred embodiment of the present invention, the pH adjuster is selected from at least one of ammonia water, ammonia gas, and alkali metal hydroxide.

[0032] According to a preferred embodiment of the present invention, step (2) comprises: dissolving the Mo source to obtain solution II; dissolving the C source to obtain solution III; dissolving the B source, Fe source, Bi source and Ni source to obtain solution IV; then adding material II, material III and material IV to the precursor to obtain a slurry, heat treating, drying and calcining.

[0033] By adopting the above-mentioned preferred preparation scheme, the activity and stability of the catalyst can be further improved.

[0034] In the present invention, the heat treatment conditions can be conventionally selected in the art. According to a preferred embodiment of the present invention, the heat treatment conditions include: a temperature of 80-150°C, and a time selected according to the temperature change, which is 10-60 minutes. The present invention takes heat treatment at 110°C for 30 minutes as an example to illustrate the advantages of the present invention.

[0035] In the present invention, each element source refers to a soluble compound of the corresponding element.

[0036] According to a preferred embodiment of the present invention, the free [H + ] concentration is 10 -10.2 -10 - 8.5 mol / L; the particle size of the carrier in the precursor is 6-13nm; the specific surface area is 200-600m 2 By adopting the above preferred embodiment, the activity and stability of the catalyst can be further improved.

[0037] According to a preferred embodiment of the present invention, the drying method is spray drying, and the conditions of the spray drying preferably include: the evaporation rate of water is 7-13 L / h;

[0038] In the present invention, the calcination conditions may be conventionally selected in the art. According to a preferred embodiment of the present invention, the calcination conditions include: calcination at 550-680° C. in an oxygen-containing atmosphere for 0.5-5 hours.

[0039] According to a preferred embodiment of the present invention, the calcination is carried out in a rotary calcination furnace, and the oxygen-containing atmosphere may be, for example, air.

[0040] The present invention provides an application of the catalyst of the present invention in olefin ammoxidation reaction.

[0041] The molybdenum-bismuth-iron catalyst of the present invention is applied to the olefin ammoxidation reaction, which not only has a higher yield of nitrile compounds (especially acrylonitrile) under a higher olefin (especially propylene) load, but also has excellent stability, and the production efficiency and economic benefits of the device are good.

[0042] The present invention provides a method for ammoxidation of propylene, which comprises: contacting and reacting a propylene raw material, an ammonia raw material and an oxygen raw material under catalyst conditions; wherein the catalyst is the catalyst described in the present invention.

[0043] According to a preferred embodiment of the present invention, the conditions of the contact reaction include: the molar ratio of propylene raw material calculated as propylene: ammonia raw material calculated as ammonia: oxygen raw material calculated as oxygen is 1:1.05-1.35:1.6-2.6, preferably 1:1.1-1.3:1.8-2.4.

[0044] According to a preferred embodiment of the present invention, the conditions of the contact reaction include: the reaction temperature is 400-480°C, preferably 410-450°C.

[0045] According to a preferred embodiment of the present invention, the conditions of the contact reaction include: the reaction pressure is 0.02-0.15 MPaG, preferably 0.03-0.09 MPaG.

[0046] According to a preferred embodiment of the present invention, the contact reaction conditions include: a weight hourly space velocity of 0.04-0.12h -1 , preferably 0.05-0.10h -1 .

[0047] The present invention adopts a reaction temperature of 430°C, a reaction pressure of 84 kPaG, a catalyst loading of 400 g, a catalyst propylene load (WWH) of 0.09 hours -1 , the raw material ratio (molar) C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0 is taken as an example to illustrate the advantages of the present invention.

[0048] The present invention will be described in detail below through examples.

[0049] In the following embodiments:

[0050] The laser Raman test was carried out on a French Lab Ram confocal microscopic laser Raman spectrometer. The excitation light was He-Ne laser with a wavelength of 632.8nm, a power of 3.0mV, and a resolution of 1cm. -1 ;

[0051] The specific surface area of ​​the precursor is calculated by measuring the number of silanol groups by titration and then by an empirical formula;

[0052] The particle size of the precursor was measured using a nanoparticle sizer;

[0053] Free [H + ]The concentration was measured by a pH meter;

[0054] All raw materials are commercially available.

[0055] Example 1

[0056] 1. Catalyst Preparation

[0057] Water was added to potassium hydroxide and heated to dissolve to obtain solution I. Solution I, 25% ammonia water and 40% silica sol were mixed to obtain a precursor. The particle size of the carrier in the precursor was measured to be 13 nm and the specific surface area was 450 m 2 / g, free [H + ] concentration is 10 -10.0 mol / L; ammonium heptamolybdate (NH4)6Mo7O 24 ·4H2O is dissolved in 80℃ hot water to obtain material II; neodymium nitrate Nd(NO3)3·6H2O is added to water and heated to dissolve to obtain material III; bismuth nitrate Bi(NO3)3·5H2O, magnesium nitrate Mg(NO3)2·6H2O, nickel nitrate Ni(NO3)2·6H2O, and iron nitrate Fe(NO3)3·9H2O are mixed, and heated to dissolve in water to obtain material IV; then materials II, III, and IV are added to the precursor to obtain a catalyst slurry. The slurry is heat treated at 110℃ for 30 minutes, and then the heat-treated slurry is subjected to micro-spheroidal molding in a spray dryer under the condition of a water evaporation rate of 10L / h according to the usual method. Finally, a micro-spheroidal slurry with an inner diameter of 89 mm and a length of 1700 mm ( mm) in a rotary calciner in air atmosphere at 585°C for 2.0 hours to prepare a catalyst composition, by mass fraction:

[0058] 50%K 0.80 Mg 3.00 Nd 2.50 Fe 1.90 Ni 5.60 Bi 1.50 Mo 12.5 O x +50%SiO2

[0059] The laser Raman spectrum of the catalyst is shown in the attached Figure 1 , visible at 785cm -1 956cm -1 The peak intensity ratio at is 0.69.

[0060] 2. Catalyst application

[0061] The reaction conditions are: mm fluidized bed reactor, reaction temperature 430°C, reaction pressure 84 kPaG, catalyst loading 400 g, catalyst propylene load (WWH) 0.09 h -1 , raw material ratio (molar) C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0062] The results are shown in Table 1.

[0063] Example 2

[0064] 1. Catalyst Preparation

[0065] Water was added to potassium hydroxide and heated to dissolve to obtain solution I. Solution I, 25% ammonia water and 40% silica sol were mixed to obtain a precursor. The particle size of the carrier in the precursor was measured to be 5 nm and the specific surface area was 650 m 2 / g, free [H + ] concentration is 10 -10.0 mol / L; ammonium heptamolybdate (NH4)6Mo7O 24 ·4H2O is dissolved in 80℃ hot water to obtain material II; neodymium nitrate Nd(NO3)3·6H2O is added to water and heated to dissolve to obtain material III; bismuth nitrate Bi(NO3)3·5H2O, magnesium nitrate Mg(NO3)2·6H2O, nickel nitrate Ni(NO3)2·6H2O, and iron nitrate Fe(NO3)3·9H2O are mixed, and heated to dissolve in water to obtain material IV; then materials II, III, and IV are added to the precursor to obtain a catalyst slurry. The slurry is heat treated at 110℃ for 30 minutes, and then the heat-treated slurry is subjected to micro-spheroidal molding in a spray dryer under the condition of a water evaporation rate of 10L / h according to the usual method. Finally, a micro-spheroidal slurry with an inner diameter of 89 mm and a length of 1700 mm ( mm) in a rotary calciner in air atmosphere at 585°C for 2.0 hours to prepare a catalyst composition, by mass fraction:

[0066] 50%K 0.80 Mg 3.00 Nd 2.50 Fe 1.90 Ni 5.60 Bi 1.50 Mo 12.5 O x +50%SiO2

[0067] The laser Raman spectrum of the catalyst was measured. Figure 1 Similar, at 785cm -1 956cm -1 The peak intensity ratio at is 0.68.

[0068] 2. Catalyst application

[0069] The reaction conditions are: mm fluidized bed reactor, reaction temperature 430°C, reaction pressure 84 kPaG, catalyst loading 400 g, catalyst propylene load (WWH) 0.09 h-1 , raw material ratio (molar) C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0070] The results are shown in Table 1.

[0071] Example 3

[0072] 1. Catalyst Preparation

[0073] Water was added to potassium hydroxide and heated to dissolve to obtain solution I. Solution I, 25% ammonia water and 40% silica sol were mixed to obtain a precursor. The particle size of the carrier in the precursor was measured to be 15 nm and the specific surface area was 450 m 2 / g, free [H + ] concentration is 10 -8.5 mol / L; ammonium heptamolybdate (NH4)6Mo7O 24 ·4H2O is dissolved in 80℃ hot water to obtain material II; neodymium nitrate Nd(NO3)3·6H2O is added to water and heated to dissolve to obtain material III; bismuth nitrate Bi(NO3)3·5H2O, magnesium nitrate Mg(NO3)2·6H2O, nickel nitrate Ni(NO3)2·6H2O, and iron nitrate Fe(NO3)3·9H2O are mixed, and heated to dissolve in water to obtain material IV; then materials II, III, and IV are added to the precursor to obtain a catalyst slurry. The slurry is heat treated at 110℃ for 30 minutes, and then the heat-treated slurry is subjected to micro-spheroidal molding in a spray dryer under the condition of a water evaporation rate of 10L / h according to the usual method. Finally, a micro-spheroidal slurry with an inner diameter of 89 mm and a length of 1700 mm ( mm) in a rotary calciner in air atmosphere at 585°C for 2.0 hours to prepare a catalyst composition, by mass fraction:

[0074] 50%K 0.80 Mg 3.00 Nd 2.50 Fe 1.90 Ni 5.60 Bi 1.50 Mo 12.5 O x +50%SiO2

[0075] The laser Raman spectrum of the catalyst was measured. Figure 1 Similar, at 785cm -1 956cm -1 The peak intensity ratio at is 0.57.

[0076] 2. Catalyst application

[0077] The reaction conditions are: mm fluidized bed reactor, reaction temperature 430°C, reaction pressure 84 kPaG, catalyst loading 400 g, catalyst propylene load (WWH) 0.09 h -1 , raw material ratio (molar) C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0078] The results are shown in Table 1.

[0079] Example 4

[0080] 1. Catalyst Preparation

[0081] Water was added to potassium hydroxide and heated to dissolve to obtain solution I. Solution I, 25% ammonia water and 40% silica sol were mixed to obtain a precursor. The particle size of the carrier in the precursor was measured to be 13 nm and the specific surface area was 450 m 2 / g, free [H + ] concentration is 10 -10.0 mol / L; ammonium heptamolybdate (NH4)6Mo7O 24 ·4H2O is dissolved in 80℃ hot water to obtain material II; neodymium nitrate Nd(NO3)3·6H2O is added to water and heated to dissolve to obtain material III; bismuth nitrate Bi(NO3)3·5H2O, gallium nitrate Ga(NO3)3·9H2O, nickel nitrate Ni(NO3)2·6H2O, and iron nitrate Fe(NO3)3·9H2O are mixed, and heated to dissolve in water to obtain material IV; then materials II, III, and IV are added to the precursor to obtain a catalyst slurry. The slurry is heat treated at 110℃ for 30 minutes, and then the heat-treated slurry is subjected to micro-sphere forming in a spray dryer under the condition of a water evaporation rate of 10L / h according to the conventional method. Finally, a micro-sphere with an inner diameter of 89 mm and a length of 1700 mm ( mm) in a rotary calciner in air atmosphere at 585°C for 2.0 hours to prepare a catalyst composition, by mass fraction:

[0082] 50%K 0.80 Ga 3.00 Nd 2.50 Fe 1.90 Ni 5.60 Bi 1.50 Mo 12.5 O x +50%SiO2

[0083] The laser Raman spectrum of the catalyst is shown in the attached Figure 1 Similar, at 785cm -1 956cm -1 The peak intensity ratio at is 0.79.

[0084] 2. Catalyst application

[0085] The reaction conditions are: mm fluidized bed reactor, reaction temperature 430°C, reaction pressure 84 kPaG, catalyst loading 400 g, catalyst propylene load (WWH) 0.09 h -1 , raw material ratio (molar) C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0086] The results are shown in Table 1.

[0087] Example 5

[0088] 1. Catalyst Preparation

[0089] Water was added to potassium hydroxide and heated to dissolve to obtain solution I. Solution I, 25% ammonia water and 40% silica sol were mixed to obtain a precursor. The particle size of the carrier in the precursor was measured to be 13 nm and the specific surface area was 450 m 2 / g, free [H + ] concentration is 10 -10.4 mol / L; ammonium heptamolybdate (NH4)6Mo7O 24 ·4H2O is dissolved in 80℃ hot water to obtain material II; neodymium nitrate Nd(NO3)3·6H2O is added to water and heated to dissolve to obtain material III; bismuth nitrate Bi(NO3)3·5H2O, magnesium nitrate Mg(NO3)2·6H2O, nickel nitrate Ni(NO3)2·6H2O, and iron nitrate Fe(NO3)3·9H2O are mixed, and heated to dissolve in water to obtain material IV; then materials II, III, and IV are added to the precursor to obtain a catalyst slurry. The slurry is heat treated at 110℃ for 30 minutes, and then the heat-treated slurry is subjected to micro-spheroidal molding in a spray dryer under the condition of a water evaporation rate of 10L / h according to the usual method. Finally, a micro-spheroidal slurry with an inner diameter of 89 mm and a length of 1700 mm ( mm) in a rotary calciner in air atmosphere at 585°C for 2.0 hours to prepare a catalyst composition, by mass fraction:

[0090] 50%K 0.80 Mg 3.00 Nd 2.50 Fe 1.90 Ni 5.60 Bi 1.50 Mo 12.5 O x +50%SiO2

[0091] The laser Raman spectrum of the catalyst and the Figure 1 Similar, at 785cm -1 956cm -1The peak intensity ratio at is 0.80.

[0092] 2. Catalyst application

[0093] The reaction conditions are: mm fluidized bed reactor, reaction temperature 430°C, reaction pressure 84 kPaG, catalyst loading 400 g, catalyst propylene load (WWH) 0.09 h -1 , raw material ratio (molar) C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0094] The results are shown in Table 1.

[0095] Example 6

[0096] 1. Catalyst Preparation

[0097] Water was added to potassium hydroxide and heated to dissolve to obtain solution I. Solution I, 25% ammonia water and 40% silica sol were mixed to obtain a precursor. The particle size of the carrier in the precursor was measured to be 15 nm and the specific surface area was 450 m 2 / g, free [H + ] concentration is 10 -10.0 mol / L; ammonium heptamolybdate (NH4)6Mo7O 24 ·4H2O is dissolved in 80℃ hot water to obtain material II; neodymium nitrate Nd(NO3)3·6H2O is added to water and heated to dissolve to obtain material III; bismuth nitrate Bi(NO3)3·5H2O, magnesium nitrate Mg(NO3)2·6H2O, nickel nitrate Ni(NO3)2·6H2O, and iron nitrate Fe(NO3)3·9H2O are mixed, and heated to dissolve in water to obtain material IV; then materials II, III, and IV are added to the precursor to obtain a catalyst slurry. The slurry is heat treated at 110℃ for 30 minutes, and then the heat-treated slurry is subjected to micro-spheroidal molding in a spray dryer under the condition of a water evaporation rate of 10L / h according to the usual method. Finally, a micro-spheroidal slurry with an inner diameter of 89 mm and a length of 1700 mm ( mm) in a rotary calciner in air atmosphere at 585°C for 2.0 hours to prepare a catalyst composition, by mass fraction:

[0098] 50%K 0.80 Mg 3.00 Nd 2.50 Fe 1.90 Ni 5.60 Bi 1.50 Mo 12.5 O x +50%SiO2

[0099] The laser Raman spectrum of the catalyst and the Figure 1Similar, at 785cm -1 956cm -1 The peak intensity ratio at is 0.56.

[0100] 2. Catalyst application

[0101] The reaction conditions are: mm fluidized bed reactor, reaction temperature 430°C, reaction pressure 84 kPaG, catalyst loading 400 g, catalyst propylene load (WWH) 0.09 h -1 , raw material ratio (molar) C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0102] The results are shown in Table 1.

[0103] Example 7

[0104] 1. Catalyst Preparation

[0105] Water was added to potassium hydroxide and heated to dissolve to obtain solution I. Solution I was mixed with silica sol having a weight concentration of 40%, and ammonia gas was introduced to obtain a precursor. The particle size of the carrier in the precursor was measured to be 15 nm and the specific surface area was 450 m 2 / g, free [H + ] concentration is 10 -10.4 mol / L; ammonium heptamolybdate (NH4)6Mo7O 24 ·4H2O is dissolved in 80℃ hot water to obtain material II; neodymium nitrate Nd(NO3)3·6H2O is added to water and heated to dissolve to obtain material III; bismuth nitrate Bi(NO3)3·5H2O, magnesium nitrate Mg(NO3)2·6H2O, nickel nitrate Ni(NO3)2·6H2O, and iron nitrate Fe(NO3)3·9H2O are mixed, and heated to dissolve in water to obtain material IV; then materials II, III, and IV are added to the precursor to obtain a catalyst slurry. The slurry is heat treated at 110℃ for 30 minutes, and then the heat-treated slurry is subjected to micro-spheroidal molding in a spray dryer under the condition of a water evaporation rate of 10L / h according to the usual method. Finally, a micro-spheroidal slurry with an inner diameter of 89 mm and a length of 1700 mm ( mm) in a rotary calciner in air atmosphere at 585°C for 2.0 hours to prepare a catalyst composition, by mass fraction:

[0106] 50%K 0.80 Mg 3.00 Nd 2.50 Fe 1.90 Ni 5.60 Bi 1.50 Mo 12.5 O x +50%SiO2

[0107] The laser Raman spectrum of the catalyst and the Figure 1 Similar, at 785cm -1 956cm -1 The peak intensity ratio at is 0.69.

[0108] 2. Catalyst application

[0109] The reaction conditions are: mm fluidized bed reactor, reaction temperature 430°C, reaction pressure 84 kPaG, catalyst loading 400 g, catalyst propylene load (WWH) 0.09 h -1 , raw material ratio (molar) C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0110] The results are shown in Table 1.

[0111] Comparative Example 1

[0112] 1. Catalyst Preparation

[0113] Add water to potassium hydroxide and heat to dissolve to obtain material I; ammonium heptamolybdate (NH4)6Mo7O 24 ·4H2O is dissolved in 80℃ hot water to obtain material II; bismuth nitrate Bi(NO3)3·5H2O, magnesium nitrate Mg(NO3)2·6H2O, nickel nitrate Ni(NO3)2·6H2O and iron nitrate Fe(NO3)3·9H2O are mixed, and the mixture is heated with water to dissolve as material III; neodymium nitrate Nd(NO3)3·6H2O is added to water, and the mixture is heated to dissolve to obtain material IV.

[0114] Material I was mixed with silica sol with a weight concentration of 40%, and the particle size of the carrier in the precursor was measured to be 25 nm and the specific surface area was 100 m 2 / g, free [H + ] concentration is 10 -9.3 mol / L; add the material II and the material III in sequence under stirring, and then add the material IV to obtain a catalyst slurry, heat treat the slurry at 110°C for 30 minutes, and then form microspheres in a spray dryer according to the usual method. Finally, in a 89 mm inner diameter and 1700 mm length ( mm) in a rotary calcining furnace at 585°C for 2.0 hours to prepare a catalyst composition, by mass fraction:

[0115] 50%K 0.80 Mg 3.00 Nd 2.50 Fe 1.90 Ni 5.60 Bi 1.50 Mo12.5 O x +50%SiO2

[0116] The laser Raman spectrum of the catalyst was measured at 785 cm -1 956cm -1 The peak intensity ratio at is 0.42.

[0117] 2. Catalyst application

[0118] The reaction conditions are: mm fluidized bed reactor, reaction temperature 430°C, reaction pressure 84 kPaG, catalyst loading 400 g, catalyst propylene load (WWH) 0.09 h -1 , raw material ratio (molar) C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0119] The results are shown in Table 1.

[0120] Comparative Example 2

[0121] 1. Catalyst Preparation

[0122] Water was added to potassium hydroxide and heated to dissolve to obtain solution I. Solution I, 25% ammonia water and 40% silica sol were mixed to obtain a precursor. The particle size of the carrier in the precursor was measured to be 3 nm and the specific surface area was 700 m 2 / g, free [H + ] concentration is 10 -9.0 mol / L; ammonium heptamolybdate (NH4)6Mo7O 24 ·4H2O is dissolved in 80℃ hot water to obtain material II; neodymium nitrate Nd(NO3)3·6H2O is added to water and heated to dissolve to obtain material III; bismuth nitrate Bi(NO3)3·5H2O, magnesium nitrate Mg(NO3)2·6H2O, nickel nitrate Ni(NO3)2·6H2O, and iron nitrate Fe(NO3)3·9H2O are mixed, and heated to dissolve in water to obtain material IV; then materials II, III, and IV are added to the precursor to obtain a catalyst slurry. The slurry is heat treated at 110℃ for 30 minutes, and then the heat-treated slurry is subjected to micro-spheroidal molding in a spray dryer under the condition of a water evaporation rate of 10L / h according to the usual method. Finally, a micro-spheroidal slurry with an inner diameter of 89 mm and a length of 1700 mm ( mm) in a rotary calciner in air atmosphere at 585°C for 2.0 hours to prepare a catalyst composition, by mass fraction:

[0123] 50%K 0.80 Mg 3.00 Nd 2.50 Fe 1.90 Ni 5.60Bi 1.50 Mo 12.5 O x +50%SiO2

[0124] The laser Raman spectrum of the catalyst was measured at 785 cm -1 956cm -1 The peak intensity ratio at is 0.52.

[0125] 2. Catalyst application

[0126] The reaction conditions are: mm fluidized bed reactor, reaction temperature 430°C, reaction pressure 84 kPaG, catalyst loading 400 g, catalyst propylene load (WWH) 0.09 h -1 , raw material ratio (molar) C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0127] The results are shown in Table 1.

[0128] Comparative Example 3

[0129] 1. Catalyst Preparation

[0130] Water was added to potassium hydroxide and heated to dissolve to obtain solution I. Solution I, 25% ammonia water and 40% silica sol were mixed to obtain a precursor. The particle size of the carrier in the precursor was measured to be 35 nm and the specific surface area was 90 m 2 / g, free [H + ] concentration is 10 -10.2 mol / L; ammonium heptamolybdate (NH4)6Mo7O 24 ·4H2O is dissolved in 80℃ hot water to obtain material II; neodymium nitrate Nd(NO3)3·6H2O is added to water and heated to dissolve to obtain material III; bismuth nitrate Bi(NO3)3·5H2O, magnesium nitrate Mg(NO3)2·6H2O, nickel nitrate Ni(NO3)2·6H2O, and iron nitrate Fe(NO3)3·9H2O are mixed, and heated to dissolve in water to obtain material IV; then materials II, III, and IV are added to the precursor to obtain a catalyst slurry. The slurry is heat treated at 110℃ for 30 minutes, and then the heat-treated slurry is subjected to micro-spheroidal molding in a spray dryer under the condition of a water evaporation rate of 10L / h according to the usual method. Finally, a micro-spheroidal slurry with an inner diameter of 89 mm and a length of 1700 mm ( mm) in a rotary calciner in air atmosphere at 585°C for 2.0 hours to prepare a catalyst composition, by mass fraction:

[0131] 50%K 0.80 Mg 3.00 Nd 2.50 Fe1.90 Ni 5.60 Bi 1.50 Mo 12.5 O x +50%SiO2

[0132] The laser Raman spectrum of the catalyst was measured at 785 cm -1 956cm -1 The peak intensity ratio at is 0.16.

[0133] 2. Catalyst application

[0134] The reaction conditions are: mm fluidized bed reactor, reaction temperature 430°C, reaction pressure 84 kPaG, catalyst loading 400 g, catalyst propylene load (WWH) 0.09 h -1 , raw material ratio (molar) C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0135] The results are shown in Table 1.

[0136] Comparative Example 4

[0137] 1. Catalyst Preparation

[0138] Water was added to potassium hydroxide and heated to dissolve to obtain solution I. Solution I, 25% ammonia water and 40% silica sol were mixed to obtain a precursor. The particle size of the carrier in the precursor was measured to be 13 nm and the specific surface area was 450 m 2 / g, free [H + ] concentration is 10 -10.0 mol / L; ammonium heptamolybdate (NH4)6Mo7O 24 ·4H2O is dissolved in 80℃ hot water to obtain material II; neodymium nitrate Nd(NO3)3·6H2O is added to water and heated to dissolve to obtain material III; bismuth nitrate Bi(NO3)3·5H2O, magnesium nitrate Mg(NO3)2·6H2O, nickel nitrate Ni(NO3)2·6H2O, and iron nitrate Fe(NO3)3·9H2O are mixed, and heated to dissolve in water to obtain material IV; then materials II, III, and IV are added to the precursor to obtain a catalyst slurry. The slurry is heat treated at 110℃ for 30 minutes, and then the heat-treated slurry is subjected to micro-spheroidal molding in a spray dryer under the condition of a water evaporation rate of 10L / h according to the usual method. Finally, a micro-spheroidal slurry with an inner diameter of 89 mm and a length of 1700 mm ( mm) in a rotary calcination furnace at 585°C in a nitrogen atmosphere for 2.0 hours to prepare a catalyst.

[0139] 2. Catalyst application

[0140] The reaction conditions are: mm fluidized bed reactor, reaction temperature 430°C, reaction pressure 84 kPaG, catalyst loading 400 g, catalyst propylene load (WWH) 0.09 h -1 , raw material ratio (molar) C3H6 / NH3 / oxygen = 1 / 1.25 / 2.0.

[0141] The results are shown in Table 1.

[0142] Table 1

[0143]

[0144] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A molybdenum-bismuth-iron catalyst, characterized in that The catalyst comprises a carrier and an active component, wherein the active component has a formula A a B b C c Fe d Ni e Bi f Mo 12.5 O x The composition shown, In the formula, A is at least one of alkali metal elements, B is at least one of alkaline earth metal elements, transition metal elements and Group IIIA metal elements, and C is at least one of lanthanide metal elements; a is in the range of 0.01-2.50; b is in the range of 0.10-10.00; c is in the range of 0.01-5.00; d is in the range of 0.01-5.00; e is in the range of 1.00-10.00; f is in the range of 0.01-5.00; x is the total number of oxygen atoms required to satisfy the valence of each element in the catalyst; In the laser Raman spectrum of the catalyst, at 785±2cm -1 and 956±2cm -1 The intensity ratio at is 0.55-0.

80.

2. The catalyst according to claim 1, wherein In the laser Raman spectrum of the catalyst, at 785±2cm -1 and 956±2cm -1 The intensity ratio at is 0.57-0.

78.

3. The catalyst according to claim 1 or 2, wherein Statement A a B b C c Fe d Ni e Bi f Mo 12.5 O x Inside, A is selected from at least one of Li, Na, K, Rb and Cs, preferably at least one of K, Rb and Cs; and / or B is selected from at least one of W, Ga, Nb, Mg, Ca, Cr and Co, preferably at least one of W, Mg, Ca, Cr and Co; and / or C is selected from at least one of La, Ce, Nd and Pr, preferably at least one of La, Ce and Nd; and / or The value range of a is 0.05-1.50; the value range of b is 1.50-9.00; the value range of c is 0.05-3.50; the value range of d is 0.05-3.00; the value range of e is 1.50-9.00; and the value range of f is 0.05-3.

00.

4. The catalyst according to any one of claims 1 to 3, wherein Based on the total mass of the catalyst, the catalyst comprises: 30-70% of a carrier; and 30-70% of an active component.

5. The catalyst according to any one of claims 1 to 4, wherein The carrier is selected from at least one of silicon dioxide, aluminum oxide, titanium oxide and zirconium oxide.

6. A method for preparing the molybdenum-bismuth-iron catalyst according to any one of claims 1 to 5, characterized in that: The preparation method comprises: (1) Preparing a precursor containing element A and a carrier, wherein free [H + ] concentration is 10 -10.5 -10 -8.4 mol / L; the particle size of the carrier in the precursor is 5-15nm, and the specific surface area is 150-650m 2 / g; (2) The precursor is mixed with a solution containing Mo, C, B, Fe, Bi, and Ni to obtain a slurry, which is then heat treated, dried, and calcined.

7. The preparation method according to claim 6, wherein: In step (1), the step of preparing the precursor includes: dissolving source A to obtain solution I, and mixing solution I, a pH adjuster and a carrier source to obtain a precursor; Step (2) comprises: dissolving the Mo source to obtain solution II; dissolving the C source to obtain solution III; dissolving the B source, Fe source, Bi source and Ni source to obtain solution IV; then adding material II, material III and material IV to the precursor to obtain a slurry, heat treating, drying and calcining.

8. The preparation method according to claim 6 or 7, wherein: The free [H + ] concentration is 10 -10.2 -10 -8.5 mol / L; the particle size of the carrier in the precursor is 6-13nm, and the specific surface area is 200-600m 2 / g; and / or The drying conditions include: the evaporation rate of water is 7-13 L / h; and / or The calcination conditions include: calcination at 550-680° C. for 0.5-5 hours in an oxygen-containing atmosphere.

9. Use of the catalyst according to any one of claims 1 to 5 in olefin ammoxidation reaction.

10. A method for the ammoxidation of propylene, characterized in that: The method comprises: contacting and reacting a propylene raw material, an ammonia raw material and an oxygen raw material under a catalyst condition; Wherein, the catalyst is the catalyst according to any one of claims 1 to 5; preferably, the conditions of the contact reaction include: The molar ratio of the propylene raw material calculated as propylene: the ammonia raw material calculated as ammonia: the oxygen raw material calculated as oxygen is 1:1.05-1.35:1.6-2.6, preferably 1:1.1-1.3:1.8-2.4; and / or The reaction temperature is 400-480°C, preferably 410-450°C; and / or The reaction pressure is 0.02-0.15 MPaG, preferably 0.03-0.09 MPaG; and / or Weight hourly space velocity is 0.04-0.12h -1 , preferably 0.05-0.10h -1 .

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