Dehydrogenation catalyst with low bulk density as well as preparation method and application thereof

Abstract

The invention provides a dehydrogenation catalyst as well as a preparation method and application thereof. The chemical composition of the dehydrogenation catalyst provided by the invention comprises Fe2O3, K2O, CeO2, MoO3, MgO, ZnO and at least one selected from MnO2 and TiO2. The method for preparing the dehydrogenation catalyst comprises the following steps: (1) mixing an iron source, a potassium source, a first cerium source, a molybdenum source, a magnesium source, a zinc source, a manganese source and / or a titanium source with a binder to obtain dry powder; and (2) mixing a solution containing a second cerium source with the dry powder, adjusting the pH value, and carrying out wet kneading, molding, drying and roasting to obtain the dehydrogenation catalyst. The dehydrogenation catalyst provided by the invention has the characteristics of low bulk density and moderate strength, can be used for catalyzing ethylbenzene dehydrogenation to prepare styrene, has high activity and long service life, and reduces the industrial production cost.

Description

Technical Field

[0001] The invention relates to the field of catalytic technology, and in particular to a low bulk density dehydrogenation catalyst and a preparation method and application thereof. Background Art

[0002] The catalytic dehydrogenation of ethylbenzene is the dominant technical route for the industrial production of styrene, and its production capacity accounts for about 85% of the total styrene production capacity. One of the keys to this method is the catalyst for the dehydrogenation of ethylbenzene to produce styrene.

[0003] At present, the basic components of the catalyst for the dehydrogenation of ethylbenzene to prepare styrene in industry include a main catalyst, a co-catalyst, a pore-forming agent and a binder. The main components of the current catalysts are basically composite / mixed oxides of Fe-K-Ce-Mo. The performance of commercial ethylbenzene dehydrogenation catalysts for preparing styrene is close to the thermodynamic equilibrium value, and the research and development of catalysts is developing towards personalization and customization. Catalysts with low bulk density can reduce the loading amount of the reactor, thereby reducing production costs. However, the problem with low bulk density dehydrogenation catalysts is that the strength is not high, and the styrene device is becoming increasingly large-scale, the bed thickness and bed height of each reactor are greatly increased, and the service life of the catalyst is prolonged, which has higher requirements for the strength of the catalyst.

[0004] In the prior art, the mechanical strength of the catalyst is enhanced by adding a combination of vanadium, cobalt, manganese and titanium oxides to the Fe-K-Ce-Mo-Mg system and optimizing the preparation process. However, this type of catalyst contains vanadium, which is toxic and pollutes the environment. In addition, a certain amount of cement, silica gel, etc. are added as reinforcing agents to improve the mechanical strength of the catalyst. However, these reinforcing agents are generally acidic substances, which are easily added to the catalyst to cause side reactions such as cracking, affecting the selectivity of the catalyst. As new styrene plants are increasingly developing towards large-scale, many new plants are larger than 350,000 tons / year. High-strength catalysts can reduce bed resistance and extend the ability of catalysts to operate for a long period of time.

[0005] In summary, the development of dehydrogenation catalysts with low bulk density and high mechanical strength is of great significance for the production of styrene. Summary of the invention

[0006] In order to solve one of the above technical problems existing in the prior art, the present invention provides a dehydrogenation catalyst and a preparation method and application thereof. The dehydrogenation catalyst of the present invention has the characteristics of low bulk density and medium strength, exhibits excellent catalytic performance in the dehydrogenation of ethylbenzene to prepare styrene, has a long service life, can greatly reduce the loading amount of the reactor, and thus reduce the production cost.

[0007] The first aspect of the present invention provides a low bulk density dehydrogenation catalyst, the chemical composition of which includes Fe 2 O 3, K 2 O、CeO 2 、MoO 3 , MgO, ZnO and selected from MnO 2 and TiO 2 At least one of .

[0008] In terms of weight percentage, Fe 2 O 3 The content of may be 70-82%, for example 70%, 72%, 75%, 78%, 80%, 82% or any value therebetween.

[0009] In terms of weight percentage, K in the above catalyst 2 The content of O may be 7-14%, for example 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% or any value therebetween.

[0010] In terms of weight percentage, CeO in the above catalyst 2 The content of may be 8-14%, for example 8%, 9%, 10%, 11%, 12%, 13%, 14% or any value therebetween.

[0011] In terms of weight percentage, the MoO 3 The content of may be 0.5-2%, for example 0.5%, 0.8%, 1.0%, 1.2%, 1.5%, 1.8%, 2% or any value therebetween.

[0012] In terms of weight percentage, the content of MgO in the above catalyst can be 0.5-3.5%, for example, 0.5%, 1.0%, 1.5%, 2%, 2.5%, 3%, 3.5% or any value therebetween.

[0013] In terms of weight percentage, the ZnO content in the above catalyst can be 0.1-2%, for example 0.1%, 0.3%, 0.5%, 0.8%, 1.0%, 1.2%, 1.5%, 1.8%, 2% or any value therebetween.

[0014] In terms of weight percentage, the MnO in the above catalyst is 2 and / or TiO 2 The total content of can be 0.01-0.5%, for example 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5% or any value therebetween.

[0015] In some embodiments, the chemical composition of the catalyst comprises, by weight percentage:

[0016] (a) 70 to 82% Fe 2O 3 ;

[0017] (b) 7-14% K 2 O;

[0018] (c) 8-14% CeO 2 ;

[0019] (d) 0.5-2% MoO 3 ;

[0020] (e) 0.5 to 3.5% MgO;

[0021] (f) 0.1-2% ZnO;

[0022] (g) 0.01-0.5% MnO 2 and / or TiO 2 .

[0023] In some embodiments, the chemical composition of the catalyst comprises, by weight percentage:

[0024] (a) 70 to 75% Fe 2 O 3 ;

[0025] (b) 10-14% K 2 O;

[0026] (c) 8-12% CeO 2 ;

[0027] (d) 1-2% MoO 3 ;

[0028] (e) 1-2% MgO;

[0029] (f) 0.5-2% ZnO;

[0030] (g) 0.05-0.3% MnO 2 ;

[0031] (h) 0.01-0.1% TiO 2 .

[0032] Potassium Ferrite KFe 11 O 17 The grain size of the catalyst will affect the mechanical strength and bulk density of the dehydrogenation catalyst, and therefore needs to be controlled within an appropriate range. In some embodiments, the catalyst contains potassium ferrite KFe 11 O 17 The grain size is 50-70nm.

[0033] In some embodiments, the bulk density of the catalyst is 1.10 to 1.38 g / mL.

[0034] In some embodiments, the mechanical strength of the catalyst is 220-260 N / cm.

[0035] The second aspect of the present invention provides a method for preparing the dehydrogenation catalyst according to the first aspect of the present invention, comprising the following steps:

[0036] (1) mixing an iron source, a potassium source, a first cerium source, a molybdenum source, a magnesium source, a zinc source, a manganese source and / or a titanium source with a binder to obtain a dry powder;

[0037] (2) Mixing a solution containing a second cerium source with the dry powder, adjusting the pH value, and performing wet kneading, molding, drying and calcining to obtain the dehydrogenation catalyst.

[0038] In the present invention, the second cerium source is a water-soluble cerium source, including at least one of cerium nitrate, cerium acetate, and ammonium cerium nitrate. In some embodiments, the first cerium source is selected from at least one of cerium carbonate, cerium oxalate, basic cerium carbonate, cerium nitrate, cerium acetate, and ammonium cerium nitrate, preferably at least one of cerium carbonate, cerium oxalate, and basic cerium carbonate.

[0039] In some embodiments, the first cerium source is different from the second cerium source.

[0040] In some embodiments, in step (2), the mass of the second cerium source accounts for 15% to 85% (in terms of CeO 2 %, such as 15%, 25%, 35%, 45%, 55%, 65%, 75%, 85% or any value therebetween.

[0041] In some embodiments, the iron source includes iron oxide. In some embodiments, the iron source includes red iron oxide and yellow iron oxide. In some embodiments, the mass ratio of the red iron oxide to the yellow iron oxide is (1-3):1.

[0042] The potassium source used in the present invention is added in the form of potassium carbonate or hydroxide; the cerium source used is added in the form of cerium salt or hydroxide; the molybdenum source used is added in the form of molybdenum salt or oxide; the magnesium source used is added in the form of magnesium oxide or hydroxide; the zinc source used is added in the form of zinc oxide or hydroxide; the manganese source is added in the form of manganese salt or oxide; and the titanium source is added in the form of titanium salt or oxide.

[0043] In the present invention, based on the total mass of the iron source, potassium source, first cerium source, second cerium source, molybdenum source, magnesium source, zinc source, manganese source and / or titanium source, Fe 2 O 3The mass proportion of the iron source is 70-82%, preferably 70-75%; 2 The mass proportion of potassium source in terms of CeO is 7-14%, preferably 10-14%; 2 The sum of the mass proportions of the first cerium source and the second cerium source is 8 to 14%, preferably 8 to 12%; 3 The mass proportion of the molybdenum source calculated as MgO is 0.5-2%, preferably 1-2%; the mass proportion of the magnesium source calculated as MgO is 0.5-3.5%, preferably 1-2%; the mass proportion of the zinc source calculated as ZnO is 0.1-2%, preferably 0.5-2%; the mass proportion of the zinc source calculated as MnO is 0.1-2%, preferably 0.5-2%; 2 The mass proportion of manganese source is 0-0.5%, preferably 0.05-0.3%; 2 The mass proportion of the titanium source is 0 to 0.5%, preferably 0.01 to 0.1%.

[0044] In some embodiments, the total mass of the manganese source and / or titanium source accounts for 0.01-0.5% of the total mass of the iron source, potassium source, first cerium source, second cerium source, molybdenum source, magnesium source, zinc source, manganese source and / or titanium source.

[0045] The binder used in the present invention is an organic polymer compound. In some embodiments, the binder includes at least two of methyl cellulose, sodium carboxymethyl cellulose, hydroxypropyl methyl cellulose and hydroxyethyl cellulose. In some preferred embodiments, the binder includes sodium carboxymethyl cellulose and hydroxyethyl cellulose. In some embodiments, the mass ratio of sodium carboxymethyl cellulose to hydroxyethyl cellulose is (2-5):1.

[0046] In some embodiments, the amount of the binder is 1-10% of the total mass of the iron source, potassium source, first cerium source, second cerium source, molybdenum source, magnesium source, zinc source, manganese source and / or titanium source, for example preferably 2-8%.

[0047] In some embodiments, in step (2), the pH value is adjusted to 7 to 9. In the present invention, the pH value can be adjusted by adding alkaline substances or acidic substances. Preferably, urea or ammonia water is used as the alkaline substance, and oxalic acid or acetic acid is used as the acidic substance.

[0048] In some embodiments, in step (2), the drying temperature is 30-110° C. In some embodiments, the drying comprises: drying in a heating and humidifying device at 30-50° C. for 4-10 hours, with the humidity controlled at 50-85%, and then air drying at 80-110° C. for 6-12 hours.

[0049] In some embodiments, in step (2), the calcination is: calcination at 350-450° C. for 6-12 hours, and then calcination at 850-1000° C. for 2-4 hours, and the calcination atmosphere is flowing air.

[0050] The dehydrogenation catalyst prepared by the present invention can be in various shapes such as solid cylinder, hollow cylinder, trilobate, rhombus, plum blossom, honeycomb, etc., and its diameter and particle length are not fixedly limited. Preferably, solid cylindrical particles with a diameter of 3 mm and a length of 5 to 10 mm are used.

[0051] Those skilled in the art can apply the dehydrogenation catalyst according to the existing technology, for example but not limited to, using ethylbenzene as raw material, in the presence of a catalyst, the raw material and the catalyst are contacted to react to generate styrene.

[0052] The third aspect of the present invention provides use of the dehydrogenation catalyst described in the first aspect or the dehydrogenation catalyst prepared by the method described in the second aspect in the dehydrogenation of ethylbenzene to prepare styrene.

[0053] Compared with the prior art, the present invention prepares a dehydrogenation catalyst with low bulk density and medium mechanical strength by adding oxides such as titanium and manganese to the iron-potassium-cerium-molybdenum-magnesium-zinc system, adjusting the addition form of the cerium source and controlling the dosage ratio of the soluble cerium salt. The bulk density of the catalyst can be as low as about 1.1 g / mL, and the mechanical strength can reach about 260 N / cm. At normal pressure and a liquid space velocity of 0.32 h / min, the catalyst can be used for dehydrogenation at room temperature. -1 Under the conditions of 640°C and water vapor / ethylbenzene (weight ratio) of 1.25, the ethylbenzene conversion rate can reach more than 80% for the dehydrogenation of ethylbenzene to prepare styrene, achieving good technical results. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments. The specific embodiments described herein are only used to explain the present invention and are not intended to constitute any limitation to the present invention.

[0055] The catalysts prepared in the following examples and comparative examples were evaluated for activity in an isothermal fixed bed. For the activity evaluation of the catalyst for dehydrogenation of ethylbenzene to produce styrene, the process is briefly described as follows:

[0056] The reaction raw materials are respectively fed into the preheating mixer through metering pumps, and then preheated and mixed into gaseous state before entering the reactor. The reactor is heated by electric heating wire to reach the predetermined temperature. The reactor has a stainless steel tube with an inner diameter of 1″, which can be filled with 100 ml of catalyst. The reactants flowing out of the reactor are condensed with water and analyzed for their composition by gas chromatography.

[0057] The ethylbenzene conversion rate and styrene selectivity are calculated according to the following formula:

[0058]

[0059]

[0060] The catalyst potassium ferrite KFe in the present invention 11 O 17 The grain size is calculated by XRD measurement. The XRD test is carried out on a Bruker D8 advance X-ray powder diffractometer with a tube voltage of 40 kV, a tube current of 250 mA, a Cu target, a scanning range of 4 to 70°, a scanning speed of 6 (°) / min, and a solid detector.

[0061] The bulk density of the catalyst in the present invention is measured according to the relevant provisions of GB / T 6286.

[0062] The mechanical strength of the catalyst in the present invention is measured according to the technical requirements specified in standard HG / T2782, using a DL-II intelligent particle strength meter. The sample length is 5 mm, and 40 particles are tested as a group. The arithmetic mean of the measured results is taken as the final mechanical strength value, and Newton (N) is the unit of mechanical strength.

[0063] Example 1

[0064] will be equivalent to 48.66 parts of Fe 2 O 3 of iron oxide red, equivalent to 24.33 parts of Fe 2 O 3 of iron oxide yellow, equivalent to 12.57 parts of K 2 O of potassium carbonate, equivalent to 6.13 parts of CeO 2 of cerium carbonate, equivalent to 1.53 parts of MoO 3 of ammonium molybdate, 1.39 parts of MgO, 1.19 parts of ZnO, 0.10 parts of MnO 2 , 0.02 parts TiO 2 , 3.85 parts of sodium carboxymethyl cellulose, and 1.65 parts of hydroxyethyl cellulose were stirred in a kneader for 1.2 hours to obtain 4.08 parts of CeO 2 The cerium nitrate is dissolved in water accounting for 22.5% of the total weight of the catalyst raw material, and then the cerium nitrate solution is added to the above dry powder for wet kneading, and urea is added to control the pH value of the wet kneading environment between 7-9. The wet kneading is carried out for 40 minutes, and the extruded strips are taken out and extruded into particles with a diameter of 3 mm and a length of 5 mm. The particles are first placed in a 40°C heating and humidifying device for drying for 8 hours, and the humidity is controlled at 65%; then placed in a 90°C oven for drying for 8 hours, and then calcined at 400°C for 8 hours, and then calcined in an air atmosphere at 870°C for 3 hours to obtain a finished catalyst. The catalyst composition is listed in Table 1.

[0065] Example 2

[0066] will be equivalent to 48.66 parts of Fe 2 O3 of iron oxide red, equivalent to 24.33 parts of Fe 2 O 3 of iron oxide yellow, equivalent to 12.57 parts of K 2 O of potassium carbonate, equivalent to 8.68 parts of CeO 2 of cerium carbonate, equivalent to 1.53 parts of MoO 3 of ammonium molybdate, 1.39 parts of MgO, 1.19 parts of ZnO, 0.10 parts of MnO 2 , 0.02 parts TiO 2 , 3.85 parts of sodium carboxymethyl cellulose, and 1.65 parts of hydroxyethyl cellulose were stirred in a kneader for 1.2 hours, and 1.53 parts of CeO 2 The cerium nitrate is dissolved in water accounting for 22.5% of the total weight of the catalyst raw material, and then the cerium nitrate solution is added to the above dry powder for wet kneading, and urea is added to control the pH value of the wet kneading environment between 7-9. The wet kneading is carried out for 40 minutes, and the extruded strips are taken out and extruded into particles with a diameter of 3 mm and a length of 5 mm. The particles are first placed in a 40°C heating and humidifying device for drying for 8 hours, and the humidity is controlled at 65%; then placed in a 90°C oven for drying for 8 hours, and then calcined at 400°C for 8 hours, and then calcined in an air atmosphere at 870°C for 3 hours to obtain a finished catalyst. The catalyst composition is listed in Table 1.

[0067] Example 3

[0068] will be equivalent to 48.66 parts of Fe 2 O 3 of iron oxide red, equivalent to 24.33 parts of Fe 2 O 3 Iron oxide yellow, equivalent to 12.57 parts K 2 O of potassium carbonate, equivalent to 1.53 parts of CeO 2 of cerium carbonate, equivalent to 1.53 parts of MoO 3 of ammonium molybdate, 1.39 parts of MgO, 1.19 parts of ZnO, and 0.10 parts of MnO 2 , 0.02 parts TiO 2 , 3.85 parts of sodium carboxymethyl cellulose, and 1.65 parts of hydroxyethyl cellulose were stirred in a kneader for 1.2 hours to obtain 8.68 parts of CeO 2The cerium nitrate is dissolved in water accounting for 22.5% of the total weight of the catalyst raw material, and then the cerium nitrate solution is added to the above dry powder for wet kneading, and urea is added to control the pH value of the wet kneading environment between 7-9. The wet kneading is carried out for 40 minutes, and the extruded strips are taken out and extruded into particles with a diameter of 3 mm and a length of 5 mm. The particles are first placed in a 40°C heating and humidifying device for drying for 8 hours, and the humidity is controlled at 65%; then placed in a 90°C oven for drying for 8 hours, and then calcined at 400°C for 8 hours, and then calcined in an air atmosphere at 870°C for 3 hours to obtain a finished catalyst. The catalyst composition is listed in Table 1.

[0069] Example 4

[0070] will be equivalent to 48.66 parts of Fe 2 O 3 of iron oxide red, equivalent to 24.33 parts of Fe 2 O 3 Iron oxide yellow, equivalent to 12.57 parts K 2 O of potassium carbonate, equivalent to 6.13 parts of CeO 2 of cerium carbonate, equivalent to 1.53 parts of MoO 3 of ammonium molybdate, 1.39 parts of MgO, 1.19 parts of ZnO, 0.12 parts of MnO 2 , 3.85 parts of sodium carboxymethyl cellulose, and 1.65 parts of hydroxyethyl cellulose were stirred in a kneader for 1.2 hours to obtain 4.08 parts of CeO 2 The cerium nitrate is dissolved in water accounting for 22.5% of the total weight of the catalyst raw material, and then the cerium nitrate solution is added to the above dry powder for wet kneading, and urea is added to control the pH value of the wet kneading environment between 7-9. The wet kneading is carried out for 40 minutes, and the extruded strips are taken out and extruded into particles with a diameter of 3 mm and a length of 5 mm. The particles are first placed in a 40°C heating and humidifying device for drying for 8 hours, and the humidity is controlled at 65%; then placed in a 90°C oven for drying for 8 hours, and then calcined at 400°C for 8 hours, and then calcined in an air atmosphere at 870°C for 3 hours to obtain a finished catalyst. The catalyst composition is listed in Table 1.

[0071] Example 5

[0072] will be equivalent to 48.66 parts of Fe 2 O 3 of iron oxide red, equivalent to 24.33 parts of Fe 2 O 3 Iron oxide yellow, equivalent to 12.57 parts K 2 O of potassium carbonate, equivalent to 6.13 parts of CeO 2 of cerium carbonate, equivalent to 1.53 parts of MoO 3 of ammonium molybdate, 1.39 parts of MgO, 1.19 parts of ZnO, 0.10 parts of MnO 2 , 0.02 parts TiO 2, 3.85 parts of sodium carboxymethyl cellulose, and 1.65 parts of hydroxyethyl cellulose were stirred in a kneader for 1.2 hours to obtain 4.08 parts of CeO 2 The ammonium cerium nitrate is dissolved in water accounting for 22.5% of the total weight of the catalyst raw material, and then the cerium nitrate solution is added to the above dry powder for wet kneading, and urea is added to control the pH value of the wet kneading environment between 7-9. The wet kneading is carried out for 40 minutes, and the extruded strips are taken out and extruded into particles with a diameter of 3 mm and a length of 5 mm. The particles are first placed in a 40°C heating and humidifying device for drying for 8 hours, and the humidity is controlled at 65%; then placed in a 90°C oven for drying for 8 hours, and then calcined at 400°C for 8 hours, and then calcined in an air atmosphere at 870°C for 3 hours to obtain a finished catalyst. The catalyst composition is listed in Table 1.

[0073] Comparative Example 1

[0074] will be equivalent to 48.66 parts of Fe 2 O 3 of iron oxide red, equivalent to 24.33 parts of Fe 2 O 3 Iron oxide yellow, equivalent to 12.57 parts K 2 O of potassium carbonate, equivalent to 10.21 parts of CeO 2 of cerium carbonate, equivalent to 1.53 parts of MoO 3 of ammonium molybdate, 1.39 parts of MgO, 1.19 parts of ZnO, 0.10 parts of MnO 2 , 0.02 parts TiO 2 5.5 parts of hydroxyethyl cellulose were stirred in a kneader for 1.2 hours, deionized water accounting for 22.5% of the total weight of the catalyst raw materials was added, wet kneaded for 40 minutes, and the extruded strips were taken out and extruded into particles with a diameter of 3 mm and a length of 5 mm. The particles were placed in an oven and dried at 40°C for 8 hours, then at 90°C for 9 hours, then calcined at 400°C for 8 hours, and then calcined at 870°C in an air atmosphere for 3 hours to obtain a finished catalyst. The catalyst composition is listed in Table 1.

[0075] Comparative Example 2

[0076] will be equivalent to 48.66 parts of Fe 2 O 3 of iron oxide red, equivalent to 24.33 parts of Fe 2 O 3 Iron oxide yellow, equivalent to 12.57 parts K 2 O of potassium carbonate, equivalent to 10.21 parts of CeO 2 of cerium carbonate, equivalent to 1.53 parts of MoO 3 of ammonium molybdate, 1.39 parts of MgO, 1.19 parts of ZnO, 0.10 parts of MnO 2 , 0.02 parts TiO 2, 3.85 parts of sodium carboxymethyl cellulose, and 1.65 parts of hydroxyethyl cellulose were stirred in a kneader for 1.2 hours, and deionized water accounting for 22.5% of the total weight of the catalyst raw materials was added, and wet kneading was performed for 40 minutes, and the extruded strips were taken out and extruded into particles with a diameter of 3 mm and a length of 5 mm. The particles were first placed in a 40°C heating and humidifying device for drying for 8 hours, and the humidity was controlled at 65%; then placed in a 90°C oven for drying for 8 hours, and then calcined at 400°C for 8 hours, and then calcined in an air atmosphere at 870°C for 3 hours to obtain a finished catalyst. The catalyst composition is listed in Table 1.

[0077] Comparative Example 3

[0078] will be equivalent to 48.66 parts of Fe 2 O 3 of iron oxide red, equivalent to 24.33 parts of Fe 2 O 3 Iron oxide yellow, equivalent to 12.57 parts K 2 O of potassium carbonate, equivalent to 1.53 parts of MoO 3 of ammonium molybdate, 1.39 parts of MgO, 1.19 parts of ZnO, 0.10 parts of MnO 2 , 0.02 parts TiO 2 , 3.85 parts of sodium carboxymethyl cellulose, and 1.65 parts of hydroxyethyl cellulose were stirred in a kneader for 1.2 hours, and 10.21 parts of CeO 2 The cerium nitrate is dissolved in water accounting for 22.5% of the total weight of the catalyst raw material, and then the cerium nitrate solution is added to the above dry powder for wet kneading. The wet kneading lasts for 40 minutes, and the extruded strips are taken out and extruded into particles with a diameter of 3 mm and a length of 5 mm. The particles are first placed in a 40°C heating and humidifying device for drying for 8 hours, and the humidity is controlled at 65%; then placed in a 90°C oven for drying for 8 hours, and then calcined at 400°C for 8 hours, and then calcined in an air atmosphere at 870°C for 3 hours to obtain a finished catalyst. The catalyst composition is listed in Table 1.

[0079] Table 1

[0080]

[0081] Note: W in Table 1 represents CeO 2 The percentage of the added soluble cerium source (cerium nitrate or ammonium cerium nitrate) to the total mass of the added cerium source is shown in FIG.

[0082] Catalyst performance test:

[0083] The bulk density and mechanical strength of the catalysts prepared in the above examples and comparative examples were measured, and the test results are listed in Table 2.

[0084] 100 ml of catalyst was loaded into the reactor and heated at normal pressure and liquid space velocity of 0.32 h -1The activity was evaluated under the conditions of 500 ℃, 640℃ and water vapor / ethylbenzene (weight ratio) 1.25. The test results are listed in Table 2.

[0085] Table 2

[0086]

[0087] in conclusion:

[0088] As can be seen from Table 2, compared with Comparative Examples 1-3, the schemes of Examples 1-5 of the present application, by adjusting the addition form of the cerium source, obtain a dehydrogenation catalyst with low bulk density and high mechanical strength, and have higher styrene selectivity in the dehydrogenation of ethylbenzene to produce styrene.

[0089] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. All technical variations made according to the technical solution of the present invention fall within the protection scope of the present invention.

Claims

1. A dehydrogenation catalyst, the chemical composition of which includes Fe 2 O 3 , K 2 O、CeO 2 、MoO 3 , MgO, ZnO and selected from MnO 2 and TiO 2 At least one of .

2. The dehydrogenation catalyst according to claim 1, It is characterized in that The chemical composition of the catalyst comprises, by weight percentage: (a) 70-82% Fe 2 O 3 ; (b) 7-14% K 2 O; (c) 8-14% CeO 2 ; (d) 0.5-2% MoO 3 ; (e) 0.5 to 3.5% MgO; (f) 0.1-2% ZnO; (g) 0.01-0.5% MnO 2 and / or TiO 2 .

3. The dehydrogenation catalyst according to claim 1 or 2, It is characterized in that The chemical composition of the catalyst comprises, by weight percentage: (a) 70-75% Fe 2 O 3 ; (b) 10-14% K 2 O; (c) 8-12% CeO 2 ; (d) 1-2% MoO 3 ; (e) 1-2% MgO; (f) 0.5-2% ZnO; (g) 0.05-0.3% MnO 2 ; (h) 0.01-0.1% TiO 2 .

4. The dehydrogenation catalyst according to any one of claims 1 to 3, It is characterized in that The potassium ferrate KFe 11 O 17 in the catalyst has a grain size of 50 to 70 nm; and / or, The bulk density of the catalyst is 1.10 to 1.38 g / mL, and / or, The mechanical strength of the catalyst is 220-260 N / cm.

5. A method for preparing the dehydrogenation catalyst according to any one of claims 1 to 4, comprising the following steps: (1) mixing an iron source, a potassium source, a first cerium source, a molybdenum source, a magnesium source, a zinc source, a manganese source and / or a titanium source with a binder to obtain a dry powder; (2) Mixing a solution containing a second cerium source with the dry powder, adjusting the pH value, and performing wet kneading, molding, drying and calcining to obtain the dehydrogenation catalyst.

6. The method according to claim 5, It is characterized in that The first cerium source is selected from at least one of cerium carbonate, cerium oxalate, basic cerium carbonate, cerium nitrate, cerium acetate, and ammonium cerium nitrate; and / or, The second cerium source is selected from at least one of cerium nitrate, cerium acetate, and ammonium cerium nitrate; and / or, The mass of the second cerium source accounts for 15% to 85% of the total mass of the first cerium source and the second cerium source.

7. The method according to any one of claims 5 or 6, It is characterized in that The amount of the binder is 1 to 10% of the total mass of the iron source, potassium source, first cerium source, second cerium source, molybdenum source, magnesium source, zinc source, manganese source and / or titanium source; and / or, The binder comprises at least two of methyl cellulose, sodium carboxymethyl cellulose, hydroxypropyl methyl cellulose and hydroxyethyl cellulose, preferably sodium carboxymethyl cellulose and hydroxyethyl cellulose; more preferably, the mass ratio of sodium carboxymethyl cellulose to hydroxyethyl cellulose is (2-5):

1.

8. The method according to any one of claims 5 to 7, It is characterized in that Based on the total mass of the iron source, potassium source, first cerium source, second cerium source, molybdenum source, magnesium source, zinc source, manganese source and / or titanium source, Fe 2 O 3 The mass proportion of iron source is 70-82%, and K 2 O accounts for 7-14% of the potassium source by mass. 2 The sum of the mass proportions of the first cerium source and the second cerium source is 8-14%, with MoO 3 The mass proportion of the molybdenum source in terms of MgO is 0.5-2%, the mass proportion of the magnesium source in terms of MgO is 0.5-3.5%, the mass proportion of the zinc source in terms of ZnO is 0.1-2%, and the mass proportion of the zinc source in terms of MnO is 0. 2 The mass proportion of manganese source is 0-0.5%, with TiO 2 The mass proportion of the titanium source is 0 to 0.5%.

9. The method according to any one of claims 5 to 8, It is characterized in that In step (2), the pH value is adjusted to 7-9; and / or the drying comprises: first drying at a temperature of 30-50° C. and a humidity of 50-85% for 4-10 hours, and then drying at a temperature of 80-110° C. for 6-12 hours; Preferably, an alkaline substance or an acidic substance is used to adjust the pH value. Preferably, the alkaline substance includes urea and / or ammonia water, and the acidic substance includes oxalic acid and / or acetic acid.

10. Use of the dehydrogenation catalyst according to any one of claims 1 to 4 or the dehydrogenation catalyst prepared by the method according to any one of claims 5 to 9 in the dehydrogenation of ethylbenzene to produce styrene.

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