CATALYST FOR AMMOXIDATION, METHOD FOR PRODUCING THE SAME AND METHOD FOR PRODUCING ACRYLONITRILE

Abstract

The catalyst for ammoxidation of the present invention contains a catalyst particle containing molybdenum, bismuth and iron, and has a ratio of hollow particles of 23% or less. Furthermore, a method for producing the catalyst for ammoxidation includes a step of preparing a catalyst precursor slurry containing molybdenum, bismuth and iron and having a solid concentration of 30% by mass or less, a step of spray-drying the catalyst precursor slurry at a drier inlet temperature of 120 C. to 240 C. to thereby obtain a dried particle and a step of calcining the dried particle at 500 to 750 C.

Claims

1. A catalyst for ammoxidation, comprising a catalyst particle comprising molybdenum, bismuth and iron, wherein the catalyst has a ratio of hollow particles of 23% or less.

2. The catalyst for ammoxidation according to claim 1, wherein the catalyst particle comprises a composite metal oxide having a composition represented by the following formula (1):
Mo.sub.12Bi.sub.aFe.sub.bX.sub.cY.sub.dZ.sub.eO.sub.f (1) wherein X represents at least one element selected from the group consisting of nickel, cobalt, magnesium, calcium, zinc, strontium, and barium; Y represents at least one element selected from the group consisting of cerium, chromium, lanthanum, neodymium, yttrium, praseodymium, samarium, aluminum, gallium, and indium; Z represents at least one element selected from the group consisting of potassium, rubidium, and cesium; and a, b, c, d, e, and f represent an atomic ratio of each element and satisfy 0.1a2.0, 0.1b3.0, 0.1c10.0, 0.1d3.0, and 0.01e2.0, respectively, wherein f represents a number of oxygen atoms needed to satisfy atomic valence requirements of the other existing elements.

3. A method for producing the catalyst for ammoxidation according to claim 1, the method comprising: a step of preparing a catalyst precursor slurry which comprises molybdenum, bismuth and iron and which has a solid concentration of 30% by mass or less, a step of spray-drying the catalyst precursor slurry at a drier inlet temperature of 120 C. to 240 C. to thereby obtain a dried particle, and a step of calcining the dried particle at 500 to 750 C.

4. The method for producing the catalyst for ammoxidation according to claim 3, wherein the catalyst precursor slurry has a solid concentration of more than 3% by mass and 30% by mass or less.

5. The method for producing the catalyst for ammoxidation according to claim 3, wherein a spray-drying apparatus having an inner diameter of 1,000 mm or more is used.

6. A method for producing acrylonitrile, the method comprising a step of reacting propylene, molecular oxygen and ammonia in a presence of the catalyst for ammoxidation according to claim 1.

Description

EXAMPLES

[0068] Hereinafter, the present embodiment will be described in more detail with reference to Examples, but the present embodiment is not limited to Examples described below. The values of the composition of the catalysts shown in Examples and Comparative Examples are the same as the values of the composition of the elements added.

Example 1

[0069] Catalyst particles in which 60% by mass of a composite metal oxide having a metal composition represented by Mo.sub.12.00Bi.sub.0.37Fe.sub.1.42Co.sub.4.47Ni.sub.3.30Ce.sub.0.91Rb.sub.0.14 was supported by 40% by mass of a carrier made of silica were produced according to the following procedure.

[0070] In a 650 liter container equipped with a stirrer, 2.85 kg of oxalic acid dihydrate dissolved in 32.81 kg of water was added to 152.17 kg of silica sol containing 30% by mass of SiO.sub.2. 54.69 kg of ammonium paramolybdate [(NH.sub.4).sub.6Mo.sub.7O.sub.24.4H.sub.2O] dissolved in 107.73 kg of water was added thereto with stirring to prepare the first solution containing molybdenum and silica. The temperature of the solution was adjusted to 45 C.

[0071] Next, 4.70 kg of bismuth nitrate [Bi(NO.sub.3).sub.3.5H.sub.2O], 14.71 kg of iron nitrate [Fe(NO.sub.3).sub.3.9H.sub.2O], 33.90 kg of cobalt nitrate [Co(NO.sub.3).sub.2.6H.sub.2O], 24.97 kg of nickel nitrate [Ni(NO.sub.3).sub.2.6H.sub.2O], 10.14 kg of cerium nitrate [Ce(NO.sub.3).sub.3.6H.sub.2O] and 0.54 kg of rubidium nitrate [RbNO.sub.3] were dissolved in 56.99 kg of 16.6% by mass nitric acid to prepare the second solution. The temperature of the solution was adjusted to 40 C.

[0072] The first solution was mixed with the second solution to prepare a precursor slurry.

[0073] At that stage, the solid concentration of the precursor slurry was 30.0% by mass.

[0074] The resulting precursor slurry was dried by using a rotary disk type spray drier having an inner diameter of the drier of 5,400 mm. Here, the temperature of air at the inlet of the drier was set to 220 C. Furthermore, the number of revolutions of the disk was set to 7,000 revolutions/minute.

[0075] The resulting dried particles were calcined at 540 C. for 8 hours to produce a catalyst.

Example 2

[0076] A catalyst in which 60% by mass of a composite metal oxide represented by the same composition as that in Example 1 was supported by 40% by mass of a carrier made of silica was produced according to the following procedure.

[0077] In a 650 liter container equipped with a stirrer, 2.68 kg of oxalic acid dihydrate dissolved in 30.76 kg of water was added to 142.67 kg of silica sol containing 30% by mass of SiO.sub.2. 51.28 kg of ammonium paramolybdate [(NH.sub.4).sub.6Mo.sub.7O.sub.24.4H.sub.2O] dissolved in 132.00 kg of water was added thereto with stirring to prepare the first solution containing molybdenum and silica. The temperature of the solution was adjusted to 45 C.

[0078] Next, 4.41 kg of bismuth nitrate [Bi(NO.sub.3).sub.3.5H.sub.2O], 13.80 kg of iron nitrate [Fe(NO.sub.3).sub.3.9H.sub.2O], 31.78 kg of cobalt nitrate [Co(NO.sub.3).sub.2.6H.sub.2O], 23.41 g of nickel nitrate [Ni(NO.sub.3).sub.2.6H.sub.2O], 9.51 kg of cerium nitrate [Ce(NO.sub.3).sub.3.6H.sub.2O] and 0.51 kg of rubidium nitrate [RbNO.sub.3] were dissolved in 53.43 kg of 16.6% by mass nitric acid to prepare the second solution. The temperature of the solution was adjusted to 40 C.

[0079] The first solution was mixed with the second solution to prepare a precursor slurry.

[0080] At that stage, the solid concentration of the precursor slurry was 28.1% by mass.

[0081] The subsequent steps were carried out in the same manner as in Example 1 to produce a catalyst.

Example 3

[0082] A catalyst was produced in the same manner as in Example 2 except for setting the drier inlet temperature to 210 C. when drying the catalyst precursor slurry.

Example 4

[0083] A catalyst in which 60% by mass of a composite metal oxide represented by the same composition as that in Example 1 was supported by 40% by mass of a carrier made of silica was produced according to the following procedure.

[0084] In a 650 liter container equipped with a stirrer, 1.90 kg of oxalic acid dihydrate dissolved in 21.86 kg of water was added to 101.39 kg of silica sol containing 30% by mass of SiO.sub.2. 36.44 kg of ammonium paramolybdate [(NH.sub.4).sub.6Mo.sub.7O.sub.24.4H.sub.2O] dissolved in 237.37 kg of water was added thereto with stirring to prepare the first solution containing molybdenum and silica.

[0085] Next, 3.13 kg of bismuth nitrate [Bi(NO.sub.3).sub.3.5H.sub.2O], 9.80 kg of iron nitrate [Fe(NO.sub.3).sub.3.9H.sub.2O], 22.59 kg of cobalt nitrate [Co(NO.sub.3).sub.2.6H.sub.2O], 16.63 kg of nickel nitrate [Ni(NO.sub.3).sub.2.6H.sub.2O], 6.76 kg of cerium nitrate [Ce(NO.sub.3).sub.3.6H.sub.2O] and 0.36 kg of rubidium nitrate [RbNO.sub.3] were dissolved in 37.97 kg of 16.6% by mass nitric acid to prepare the second solution. The temperature of the solution was adjusted to 40 C.

[0086] The first solution was mixed with the second solution to prepare a precursor slurry.

[0087] At that stage, the solid concentration of the precursor slurry was 20.0% by mass.

[0088] The subsequent steps were carried out in the same manner as in Example 3 to produce a catalyst.

Example 5

[0089] A catalyst in which 60% by mass of a composite metal oxide represented by the same composition as that in Example 1 was supported by 40% by mass of a carrier made of silica was produced according to the following procedure.

[0090] In a 650 liter container equipped with a stirrer, 0.95 kg of oxalic acid dihydrate dissolved in 10.91 kg of water was added to 50.60 kg of silica sol containing 30% by mass of SiO.sub.2. 18.18 kg of ammonium paramolybdate [(NH.sub.4).sub.6Mo.sub.7O.sub.24.4H.sub.2O] dissolved in 367.05 kg of water was added thereto with stirring to prepare the first solution containing molybdenum and silica.

[0091] Next, 1.56 kg of bismuth nitrate [Bi(NO.sub.3).sub.3.5H.sub.2O], 4.89 kg of iron nitrate [Fe(NO.sub.3).sub.3.9H.sub.2O], 11.27 kg of cobalt nitrate [Co(NO.sub.3).sub.2.6H.sub.2O], 8.30 kg of nickel nitrate [Ni(NO.sub.3).sub.2.6H.sub.2O], 3.37 kg of cerium nitrate [Ce(NO.sub.3).sub.3.6H.sub.2O] and 0.18 kg of rubidium nitrate [RbNO.sub.3] were dissolved in 18.95 kg of 16.6% by mass nitric acid to prepare the second solution. The temperature of the solution was adjusted to 40 C.

[0092] The first solution was mixed with the second solution to prepare a precursor slurry.

[0093] At that stage, the solid concentration of the precursor slurry was 10.0% by mass.

[0094] The subsequent steps were carried out in the same manner as in Example 3 to produce a catalyst.

Example 6

[0095] A catalyst in which 60% by mass of a composite metal oxide represented by the same composition as that in Example 1 was supported by 40% by mass of a carrier made of silica was produced according to the following procedure.

[0096] In a 650 liter container equipped with a stirrer, 0.29 kg of oxalic acid dihydrate dissolved in 3.29 kg of water was added to 15.24 kg of silica sol containing 30% by mass of SiO.sub.2. 5.48 kg of ammonium paramolybdate [(NH.sub.4).sub.6Mo.sub.7O.sub.24.4H.sub.2O] dissolved in 457.31 kg of water was added thereto with stirring to prepare the first solution containing molybdenum and silica.

[0097] Next, 0.47 kg of bismuth nitrate [Bi(NO.sub.3).sub.3.5H.sub.2O], 1.47 kg of iron nitrate [Fe(NO.sub.3).sub.3.9H.sub.2O], 3.40 kg of cobalt nitrate [Co(NO.sub.3).sub.2.6H.sub.2O], 2.50 kg of nickel nitrate [Ni(NO.sub.3).sub.2.6H.sub.2O], 1.02 kg of cerium nitrate [Ce(NO.sub.3).sub.3.6H.sub.2O] and 0.05 kg of rubidium nitrate [RbNO.sub.3] were dissolved in 5.71 kg of 16.6% by mass nitric acid to prepare the second solution. The temperature of the solution was adjusted to 40 C.

[0098] The first solution was mixed with the second solution to prepare a precursor slurry.

[0099] At that stage, the solid concentration of the precursor slurry was 3.0% by mass.

[0100] The subsequent steps were carried out in the same manner as in Example 1 except for setting the drier inlet temperature to 120 C. when drying the catalyst precursor slurry to produce a catalyst.

[0101] The amount of catalyst obtained by the above procedure was small, and the result was a reduction in productivity.

Example 7

[0102] A catalyst was produced in the same manner as in Example 3 except for using a drier having an inner diameter the drier of 1,600 mm when drying the catalyst precursor slurry.

Comparative Example 1

[0103] A catalyst in which 60% by mass of a composite metal oxide represented by the same composition as that in Example 1 was supported by 40% by mass of a carrier made of silica was produced according to the following procedure.

[0104] In a 650 liter container equipped with a stirrer, 2.97 kg of oxalic acid dihydrate dissolved in 34.13 kg of water was added to 158.30 kg of silica sol containing 30% by mass of SiO.sub.2. 56.89 kg of ammonium paramolybdate [(NH.sub.4).sub.6Mo.sub.7O.sub.24.4H.sub.2O] dissolved in 92.09 kg of water was added thereto with stirring to prepare the first solution containing molybdenum and silica.

[0105] Next, 4.89 kg of bismuth nitrate [Bi(NO.sub.2).sub.3.5H.sub.2O], 15.31 kg of iron nitrate [Fe(NO.sub.3).sub.3.9H.sub.2O], 35.27 kg of cobalt nitrate [Co(NO.sub.3).sub.2.6H.sub.2O], 25.97 kg of nickel nitrate [Ni(NO.sub.3).sub.2.6H.sub.2O], 10.55 kg of cerium nitrate [Ce(NO.sub.3).sub.3.6H.sub.2O] and 0.56 kg of rubidium nitrate [RbNO.sub.3] were dissolved in 59.28 kg of 16.6% by mass nitric acid to prepare the second solution. The temperature of the solution was adjusted to 40 C.

[0106] The first solution was mixed with the second solution to prepare a precursor slurry.

[0107] At that stage, the solid concentration of the precursor slurry was 31.2% by mass.

[0108] The subsequent steps were carried out in the same manner as in Example 3 to produce a catalyst.

Comparative Example 2

[0109] A catalyst was produced in the same manner as in Example 2 except for setting the drier inlet temperature to 250 C. when drying the catalyst precursor slurry.

Evaluation of Ratio of Hollow Particles

[0110] Calcined catalyst particles were embedded in an epoxy resin. Next, the resin in which the particles were embedded was polished to expose a cross-section of catalyst particles. Subsequently, osmium was deposited on the polished resin sample and the polished cross-section was observed by an electron microscope (Scanning Electron Microscope S-4800 made by Hitachi High-Technologies Corporation). The cross-section was photographed at a magnification of 100. Images were taken until the total number of particles reached 1,500 particles or more. Here, a particle in which the total area occupied by voids was 1% or more based on the area of a cross-section of a particle was determined as a hollow particle. The total number of particles and the number of hollow particles in the photographed images were counted, and the ratio of hollow particles was calculated by dividing the number of hollow particles by the total number of particles and multiplying the resultant by 100.

Measurement of Wear Resistance Strength

[0111] The wear resistance strength (attrition strength) of the catalysts was measured in terms of wear loss according to the method described in the Test Method for Synthetic Fluid Cracking Catalyst (American Cyanamid Co. Ltd. 6/31-4m-1/57) (hereinafter referred to as the ACC method).

[0112] The attrition strength is assessed based on wear loss. The wear loss is defined as follows.

Wear loss (%)=R/(SQ)100

[0113] In the above formula, Q represents the mass (g) of the catalyst which was worn and scattered to the outside during the period from 0 to 5 hours, and R usually represents the mass (g) of the catalyst which was worn and scattered to the outside during the period from 5 to 20 hours. S represents the mass (g) of the catalyst supplied to the test.

[0114] Those with a value of wear loss of 3% or less were evaluated as applicable to industrial use. Those with a value of wear loss of 0.8% or less were evaluated as being able to be used for long time in a stable manner.

Measurement of Compressive Strength

[0115] The compressive strength of catalyst particles was measured by using Micro Compression Tester (MCT-W500 made by Shimadzu Corporation). For catalyst particles whose particle diameter was previously measured by a microscope attached to the tester, the data of compressive strength (MPa) was collected by using a 200 m diameter flat cylindrical indenter at a rate of 19.4 mN/sec.

[0116] The compressive strength is calculated by the following formula.

Compressive strength (MPa)=aP/dd

[0117] In the above formula, a represents the constant 2.48 in accordance with JISR1639-5, P represents the load (N) at breakdown and d represents the particle diameter (mm).

[0118] 20 particles were measured by the above procedure and the arithmetic mean of the values obtained were calculated and determined as the value of compressive strength.

Conditions of Ammoxidation Reaction and Results

[0119] A Pyrex (registered trademark) glass pipe having an inner diameter of 25 mm and containing 16 10-mesh wire nets at intervals of 1 cm was used as a reaction pipe to be used for ammoxidation reaction of propylene. The amount of catalyst was set to 50 cc, the reaction temperature was set to 430 C. and the reaction pressure was set to 0.17 MPa. A mixed gas (propylene, ammonia, oxygen, helium) with 9% by volume of propylene was passed through the pipe. The volume ratio of ammonia to propylene was set so that the sulfuric acid unit requirement defined by the following equation was 202 kg/T-AN. The volume ratio of oxygen to propylene was set so that the oxygen concentration of gas at the outlet of the reactor was 0.20.02% by volume. The contact time defined by the following equation can be changed by changing the flow rate of the mixed gas. Accordingly, the contact time was set so that the conversion rate of propylene defined by the following equation was 99.30.2%. The yield of acrylonitrile produced by the reaction is defined as shown in the following formula.

[00001]$\mathrm{Sulfuric}.Math..Math.\mathrm{acid}.Math..Math.\mathrm{unit}.Math..Math.\mathrm{requirement}.Math..Math.\left(\mathrm{kg}.Math.\text{/}.Math.T.Math.\text{-}.Math.\mathrm{AN}\right)=\frac{.Math.\begin{array}{c}\mathrm{Weight}.Math..Math.\mathrm{of}.Math..Math.\mathrm{sulfuric}.Math..Math.\mathrm{acid}.Math..Math.\mathrm{needed}\\ \mathrm{to}.Math..Math.\mathrm{neutrailize}.Math..Math.\mathrm{unreated}.Math..Math.\mathrm{ammonia}.Math..Math.\left(\mathrm{kg}\right)\end{array}.Math.}{\mathrm{Weight}.Math..Math.\mathrm{of}.Math..Math.\mathrm{acrylonitrile}.Math..Math.\mathrm{produced}.Math..Math.\left(T\right)}$$\mathrm{Contact}.Math..Math.\mathrm{time}.Math..Math.\left(\sec .\right)=\frac{\mathrm{Amount}.Math..Math.\mathrm{of}.Math..Math.\mathrm{catalyst}.Math..Math.\left(\mathrm{cc}\right)}{\mathrm{Flow}.Math..Math.\mathrm{rate}.Math..Math.\mathrm{of}.Math..Math.\mathrm{mixed}.Math..Math.\mathrm{gas}.Math..Math.\left(\mathrm{cc}.Math.\text{-}.Math.\mathrm{NTP}.Math.\text{/}.Math.\sec .\right)}\frac{273}{273+\mathrm{Reaction}.Math..Math.\mathrm{temperature}.Math..Math.\left(.Math..Math.C.\right)}\frac{\mathrm{Reaction}.Math..Math.\mathrm{pressure}.Math..Math.\left(\mathrm{MPa}\right)}{0.10}$$\mathrm{Conversion}.Math..Math.\mathrm{rate}.Math..Math.\mathrm{of}.Math..Math.\mathrm{propylene}.Math..Math.\left(\%\right)=\frac{\mathrm{Propylene}.Math..Math.\mathrm{consumed}.Math..Math.\left(\mathrm{mol}\right)}{\mathrm{Propylene}.Math..Math.\mathrm{supplied}.Math..Math.\left(\mathrm{mol}\right)}100$$.Math.\mathrm{Yield}.Math..Math.\mathrm{of}.Math..Math.\mathrm{acrylonitrile}.Math..Math.\left(\%\right)=\frac{\mathrm{Acrylonitrile}.Math..Math.\mathrm{produced}.Math..Math.\left(\mathrm{mol}\right)}{\mathrm{Propylene}.Math..Math.\mathrm{supplied}.Math..Math.\left(\mathrm{mol}\right)}100$

[0120] The solid concentration of the slurries of catalyst precursor obtained in Examples and Comparative Examples, the drier inlet temperature, the inner diameter of the drier, the ratio of hollow particles, the compressive strength, the wear resistance strength and the yield of acrylonitrile are shown in Table 1. The reaction time was 20 hours.

TABLE-US-00001 TABLE 1 Inner Ratio of Wear Solid Drier inlet diameter hollow Compressive resistance Yield of concentration temperature of drier particles strength strength acrylonitrile (%) ( C.) (mm) (%) (Mpa) (%) (%) Example 1 30.0 220 5400 23 38 0.8 84.4 Example 2 28.1 220 5400 16 40 0.7 84.5 Example 3 28.1 210 5400 9 42 0.6 84.4 Example 4 20.0 210 5400 7 42 0.6 84.4 Example 5 10.0 210 5400 5 42 0.6 84.4 Example 6 3.0 120 5400 0 47 0.2 84.3 Example 7 28.1 210 1600 1 46 0.2 84.4 Comparative 31.2 210 5400 24 29 0.9 84.3 Example 1 Comparative 28.1 250 5400 38 30 1.3 84.4 Example 2

[0121] As shown in Table 1 above, the ratio of hollow particles and the wear resistance strength of the catalysts produced according to the present embodiment were low, and it is indicated that the strength of catalyst was increased.

[0122] Furthermore, acrylonitrile was produced at an excellent yield by ammoxidation reaction of propylene.

[0123] The present application claims the priority based on Japanese Patent Application filed on May 19, 2017 (Japanese Patent Application No. 2017-100007), the contents of which are hereby incorporated by reference.

INDUSTRIAL APPLICABILITY

[0124] The catalyst for ammoxidation of the present invention has industrial applicability as a catalyst used for ammoxidation reaction of propylene.