A low bulk density dehydrogenation catalyst, its preparation method and application

Abstract

The present application provides a dehydrogenation catalyst and a preparation method and application thereof. The chemical composition of the dehydrogenation catalyst of the present application comprises Fe2O3, K2O, CeO2, MoO3, MgO, ZnO and at least one selected from MnO2 and TiO2. The method for preparing the dehydrogenation catalyst of the present application 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; (2) mixing a solution containing a second cerium source with the dry powder, adjusting pH, wet kneading, shaping, drying and calcining to obtain the dehydrogenation catalyst. The dehydrogenation catalyst of the present application has the characteristics of low bulk density and medium strength, and can be used for catalyzing the dehydrogenation of ethylbenzene to styrene, and has high catalyst activity, long service life and reduced industrial production cost.

Description

Technical Field

[0001] This invention relates to the field of catalysis technology, specifically to a low packing density dehydrogenation catalyst, its preparation method, and its application. Background Technology

[0002] The catalytic dehydrogenation of ethylbenzene is the dominant technology for industrial styrene production, accounting for approximately 85% of the total styrene production capacity. One of the key aspects of this method is the catalyst for the ethylbenzene dehydrogenation to styrene production.

[0003] Currently, the basic components of industrial ethylbenzene dehydrogenation catalysts for styrene production include a main catalyst, a co-catalyst, a pore-forming agent, and a binder. The main components of current catalysts are primarily Fe-K-Ce-Mo composite / mixed oxides. The performance of commercial ethylbenzene dehydrogenation catalysts for styrene production has approached thermodynamic equilibrium values, and catalyst development is moving towards personalization and customization. Low-bulk-density catalysts can reduce reactor loading, thereby lowering production costs. However, low-bulk-density dehydrogenation catalysts suffer from low strength, and with the increasing size of styrene plants, the bed thickness and height of each reactor have significantly increased, leading to longer catalyst lifespans and placing higher demands on catalyst strength.

[0004] In existing technologies, the mechanical strength of catalysts 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, these catalysts contain vanadium, which is toxic and pollutes the environment. Additionally, some catalysts improve mechanical strength by adding certain amounts of cement, silica gel, etc., as reinforcing agents. However, these reinforcing agents are generally acidic and can easily cause side reactions such as cracking after being added to the catalyst, affecting its selectivity. With the increasing scale of new styrene plants, many of which have a capacity of 350,000 tons / year or more, high-strength catalysts can reduce bed resistance and extend the catalyst's long-term operating capability.

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

[0006] To address one of the aforementioned technical problems in the prior art, this invention provides a dehydrogenation catalyst, its preparation method, and its application. The dehydrogenation catalyst of this invention combines low bulk density and moderate strength, exhibiting excellent catalytic performance in the dehydrogenation of ethylbenzene to styrene. It also has a long service life and can significantly reduce the reactor loading, thereby lowering production costs.

[0007] A first aspect of the present invention provides a low packing density dehydrogenation catalyst having a chemical composition comprising Fe2O3, K2O, CeO2, MoO3, MgO, ZnO, and at least one selected from MnO2 and TiO2.

[0008] The Fe2O3 content in the above catalyst can be 70-82% by weight, for example 70%, 72%, 75%, 78%, 80%, 82% or any value between them.

[0009] The K2O content in the catalyst can be 7% to 14% by weight, for example, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% or any value between them.

[0010] The CeO2 content in the catalyst described above can be 8% to 14% by weight, for example, 8%, 9%, 10%, 11%, 12%, 13%, 14% or any value between them.

[0011] The content of MoO3 in the above catalyst can be 0.5% to 2% by weight, for example 0.5%, 0.8%, 1.0%, 1.2%, 1.5%, 1.8%, 2% or any value between them.

[0012] The MgO content in the catalyst can be 0.5% to 3.5% by weight, for example 0.5%, 1.0%, 1.5%, 2%, 2.5%, 3%, 3.5% or any value between them.

[0013] The ZnO content in the catalyst can be 0.1% to 2% by weight, for example 0.1%, 0.3%, 0.5%, 0.8%, 1.0%, 1.2%, 1.5%, 1.8%, 2% or any value between them.

[0014] The total content of MnO2 and / or TiO2 in the above catalyst can be 0.01 to 0.5% by weight, for example 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5% or any value between them.

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

[0016] (a) 70–82% Fe2O3;

[0017] (b) 7-14% K₂O;

[0018] (c) 8-14% CeO2;

[0019] (d) 0.5–2% MoO3;

[0020] (e) 0.5–3.5% MgO;

[0021] (f) 0.1–2% ZnO;

[0022] (g) 0.01-0.5% of MnO2 and / or TiO2.

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

[0024] (a) 70-75% Fe2O3;

[0025] (b) 10–14% K₂O;

[0026] (c) 8-12% CeO2;

[0027] (d) 1-2% MoO3;

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

[0029] (f) 0.5–2% ZnO;

[0030] (g) 0.05-0.3% MnO2;

[0031] (h) 0.01-0.1% TiO2.

[0032] Potassium ferrate (KFe) 11 O 17 The grain size affects the mechanical strength and packing density of the dehydrogenation catalyst, and therefore needs to be controlled within a suitable range. In some embodiments, potassium ferrite (KFe) is used in the catalyst. 11 O 17 The grain size is 50–70 nm.

[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] A second aspect of the present invention provides a method for preparing the dehydrogenation catalyst described in the first aspect of the present invention, comprising the following steps:

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

[0037] (2) The solution containing the second cerium source is mixed with the dry powder, the pH value is adjusted, and the mixture is wet-kneaded, shaped, dried and calcined to obtain the dehydrogenation catalyst.

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

[0039] In some implementations, 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 CeO2) of the total mass of the first cerium source and the second cerium source, for example, 15%, 25%, 35%, 45%, 55%, 65%, 75%, 85% or any value between them.

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

[0042] The potassium source used in this invention is added in the form of potassium carbonate or hydroxide; the cerium source is added in the form of cerium salt or hydroxide; the molybdenum source is added in the form of molybdenum salt or oxide; the magnesium source is added in the form of magnesium oxide or hydroxide; the zinc source 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 this 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, the mass percentage of the iron source (calculated as Fe2O3) is 70-82%, preferably 70-75%; the mass percentage of the potassium source (calculated as K2O) is 7-14%, preferably 10-14%; the sum of the mass percentages of the first and second cerium sources (calculated as CeO2) is 8-14%, preferably 8-12%; the mass percentage of the molybdenum source (calculated as MoO3) is 0.5-2%, preferably 1-2%; the mass percentage of the magnesium source (calculated as MgO) is 0.5-3.5%, preferably 1-2%; the mass percentage of the zinc source (calculated as ZnO) is 0.1-2%, preferably 0.5-2%; the mass percentage of the manganese source (calculated as MnO2) is 0-0.5%, preferably 0.05-0.3%; and the mass percentage of the titanium source (calculated as TiO2) is 0-0.5%, preferably 0.01-0.1%.

[0044] In some embodiments, the total mass of the manganese source and / or titanium source accounts for 0.01 to 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 this invention is an organic polymer compound. In some embodiments, the binder includes at least two of methylcellulose, sodium carboxymethylcellulose, hydroxypropyl methylcellulose, and hydroxyethylcellulose. In some preferred embodiments, the binder includes sodium carboxymethylcellulose and hydroxyethylcellulose. In some embodiments, the mass ratio of sodium carboxymethylcellulose to hydroxyethylcellulose is (2-5):1.

[0046] In some embodiments, 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, for example, 2 to 8%.

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

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

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

[0050] The dehydrogenation catalyst prepared by this invention can be in various shapes such as solid cylindrical, hollow cylindrical, trilobal, rhomboid, plum blossom, and honeycomb. There are no fixed limitations on its diameter and particle length. Solid cylindrical particles with a diameter of 3 mm and a length of 5 to 10 mm are preferred.

[0051] Those skilled in the art can apply the dehydrogenation catalyst according to existing technology and processes, for example, but not limited to, using ethylbenzene as a raw material, in the presence of the catalyst, the raw material comes into contact with the catalyst and reacts to produce styrene.

[0052] The third aspect of this invention provides the application 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 styrene.

[0053] Compared with existing technologies, this invention prepares a dehydrogenation catalyst with low packing density and moderate mechanical strength by adding oxides such as titanium and manganese to an iron-potassium-cerium-molybdenum-magnesium-zinc system, adjusting the form of cerium source addition, and controlling the proportion of soluble cerium salts. The catalyst packing density can be as low as about 1.1 g / mL, and the mechanical strength can reach about 260 N / cm. This is achieved under normal pressure and a liquid hourly space velocity (LHSV) of 0.32 h⁻¹. -1 Under conditions of 640℃ and a water vapor / ethylbenzene (weight ratio) of 1.25, the reaction for the dehydrogenation of ethylbenzene to prepare styrene can achieve an ethylbenzene conversion rate of over 80%, achieving good technical results. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way.

[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 the dehydrogenation of ethylbenzene to styrene, the process is briefly described as follows:

[0056] The reactants are separately fed into a preheating mixer via metering pumps. After being preheated and mixed into a gaseous state, the mixture enters the reactor, which is heated by an electric heating wire to reach a predetermined temperature. The reactor is a 1″ stainless steel tube that can hold 100 mL of catalyst. The reactants flowing out of the reactor are condensed in water and their composition is analyzed by gas chromatography.

[0057] Ethylbenzene conversion and styrene selectivity are calculated using the following formulas:

[0058]

[0059]

[0060] Potassium ferrite (KFe) is used as a catalyst in this invention. 11 O 17 The grain size was calculated by XRD measurement. The XRD test was performed 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 4–70°, a scanning speed of 6 (°) / min, and a solid-state detector.

[0061] The bulk density of the catalyst in this invention is determined in accordance with the relevant provisions of GB / T 6286.

[0062] In this invention, the mechanical strength of the catalyst was determined according to the technical requirements specified in standard HG / T2782, using a DL-II intelligent particle strength tester. The sample length was 5 mm, and 40 particles were tested as a group. The arithmetic mean of the test results was taken as the final mechanical strength value, expressed in Newtons (N).

[0063] Example 1

[0064] Iron oxide red (equivalent to 48.66 parts Fe2O3), iron oxide yellow (equivalent to 24.33 parts Fe2O3), potassium carbonate (equivalent to 12.57 parts K2O), cerium carbonate (equivalent to 6.13 parts CeO2), ammonium molybdate (equivalent to 1.53 parts MoO3), 1.39 parts MgO, 1.19 parts ZnO, 0.10 parts MnO2, 0.02 parts TiO2, 3.85 parts sodium carboxymethyl cellulose, and 1.65 parts hydroxyethyl cellulose were mixed in a kneader for 1.2 hours. Then, an amount equivalent to 4.08 parts CeO2 was added... Cerium nitrate (2% by weight of the catalyst raw material) was dissolved in water. This cerium nitrate solution was then added to the aforementioned dry powder for wet kneading. Urea was added to control the pH of the wet kneading environment between 7 and 9. The kneading was carried out for 40 minutes. The extruder was then removed and extruded into particles with a diameter of 3 mm and a length of 5 mm. The particles were first dried in a 40°C heated and humidified environment for 8 hours, with the humidity controlled at 65%. Then, they were dried in a 90°C oven for 8 hours, calcined at 400°C for 8 hours, and finally calcined at 870°C in air for 3 hours to obtain the finished catalyst. The catalyst composition is listed in Table 1.

[0065] Example 2

[0066] Iron oxide red (equivalent to 48.66 parts Fe2O3), iron oxide yellow (equivalent to 24.33 parts Fe2O3), potassium carbonate (equivalent to 12.57 parts K2O), cerium carbonate (equivalent to 8.68 parts CeO2), ammonium molybdate (equivalent to 1.53 parts MoO3), 1.39 parts MgO, 1.19 parts ZnO, 0.10 parts MnO2, 0.02 parts TiO2, 3.85 parts sodium carboxymethyl cellulose, and 1.65 parts hydroxyethyl cellulose were mixed in a kneader for 1.2 hours. The following ingredients were added: iron oxide red (equivalent to 48.66 parts Fe2O3), iron oxide yellow (equivalent to 24.33 parts Fe2O3), potassium carbonate (equivalent to 12.57 parts K2O), cerium carbonate (equivalent to 8.68 parts CeO2), ammonium molybdate (equivalent to 1.53 parts MoO3), MgO, ZnO, MnO2, TiO2, sodium carboxymethyl cellulose, and hydroxyethyl cellulose. Cerium nitrate (2% by weight of the catalyst raw material) was dissolved in water. This cerium nitrate solution was then added to the aforementioned dry powder for wet kneading. Urea was added to control the pH of the wet kneading environment between 7 and 9. The kneading was carried out for 40 minutes. The extruder was then removed and extruded into particles with a diameter of 3 mm and a length of 5 mm. The particles were first dried in a 40°C heated and humidified environment for 8 hours, with the humidity controlled at 65%. Then, they were dried in a 90°C oven for 8 hours, calcined at 400°C for 8 hours, and finally calcined at 870°C in air for 3 hours to obtain the finished catalyst. The catalyst composition is listed in Table 1.

[0067] Example 3

[0068] Iron oxide red (equivalent to 48.66 parts Fe2O3), iron oxide yellow (equivalent to 24.33 parts Fe2O3), potassium carbonate (equivalent to 12.57 parts K2O), cerium carbonate (equivalent to 1.53 parts CeO2), ammonium molybdate (equivalent to 1.53 parts MoO3), 1.39 parts MgO, 1.19 parts ZnO, 0.10 parts MnO2, 0.02 parts TiO2, 3.85 parts sodium carboxymethyl cellulose, and 1.65 parts hydroxyethyl cellulose were mixed in a kneader for 1.2 hours. Then, an amount equivalent to 8.68 parts CeO2 was added... Cerium nitrate of O2 was dissolved in water at 22.5% of the total weight of the catalyst raw materials. This cerium nitrate solution was then added to the above-mentioned dry powder for wet kneading. Urea was added to control the pH value of the wet kneading environment between 7 and 9. The kneading was carried out for 40 minutes. The extruder was then removed and extruded into granules with a diameter of 3 mm and a length of 5 mm. The granules were first dried in a 40°C heated and humidified device for 8 hours, with the humidity controlled at 65%. Then, they were dried in a 90°C oven for 8 hours, then calcined at 400°C for 8 hours, and finally calcined at 870°C in air atmosphere for 3 hours to obtain the finished catalyst. The catalyst composition is listed in Table 1.

[0069] Example 4

[0070] Iron oxide red (equivalent to 48.66 parts Fe2O3), iron oxide yellow (equivalent to 24.33 parts Fe2O3), potassium carbonate (equivalent to 12.57 parts K2O), cerium carbonate (equivalent to 6.13 parts CeO2), ammonium molybdate (equivalent to 1.53 parts MoO3), 1.39 parts MgO, 1.19 parts ZnO, 0.12 parts MnO2, 3.85 parts sodium carboxymethyl cellulose, and 1.65 parts hydroxyethyl cellulose were stirred in a kneader for 1.2 hours. Cerium nitrate (equivalent to 4.08 parts CeO2) was then added. The catalyst raw material was dissolved in water at 22.5% of its total weight. This cerium nitrate solution was then added to the dry powder for wet kneading. Urea was added to control the pH value of the wet kneading environment between 7 and 9. The kneading was carried out for 40 minutes. The extruder was then removed and extruded into particles with a diameter of 3 mm and a length of 5 mm. The particles were first dried in a 40°C heated and humidified environment for 8 hours, with the humidity controlled at 65%. Then, they were dried in a 90°C oven for 8 hours, calcined at 400°C for 8 hours, and then calcined in air at 870°C for 3 hours to obtain the finished catalyst. The catalyst composition is listed in Table 1.

[0071] Example 5

[0072] Iron oxide red (equivalent to 48.66 parts Fe2O3), iron oxide yellow (equivalent to 24.33 parts Fe2O3), potassium carbonate (equivalent to 12.57 parts K2O), cerium carbonate (equivalent to 6.13 parts CeO2), ammonium molybdate (equivalent to 1.53 parts MoO3), 1.39 parts MgO, 1.19 parts ZnO, 0.10 parts MnO2, 0.02 parts TiO2, 3.85 parts sodium carboxymethyl cellulose, and 1.65 parts hydroxyethyl cellulose were mixed in a kneader for 1.2 hours. Then, 4.08 parts CeO2 were added... 2% cerium ammonium nitrate was dissolved in water, which accounted for 22.5% of the total weight of the catalyst raw materials. This cerium nitrate solution was then added to the aforementioned dry powder for wet kneading. Urea was added to control the pH value of the wet kneading environment between 7 and 9. The kneading was carried out for 40 minutes. The extruder was then removed and extruded into particles with a diameter of 3 mm and a length of 5 mm. The particles were first dried in a 40°C heated and humidified environment for 8 hours, with the humidity controlled at 65%. Then, they were dried in a 90°C oven for 8 hours, calcined at 400°C for 8 hours, and finally calcined at 870°C in air for 3 hours to obtain the finished catalyst. The catalyst composition is listed in Table 1.

[0073] Comparative Example 1

[0074] Iron oxide red (equivalent to 48.66 parts Fe2O3), iron oxide yellow (equivalent to 24.33 parts Fe2O3), potassium carbonate (equivalent to 12.57 parts K2O), cerium carbonate (equivalent to 10.21 parts CeO2), ammonium molybdate (equivalent to 1.53 parts MoO3), MgO, ZnO, MnO2, TiO2, and hydroxyethyl cellulose were stirred in a kneader for 1.2 hours. Deionized water (22.5% of the total weight of the catalyst raw materials) was added, and the mixture was wet-kneaded for 40 minutes. The mixture was then extruded into granules with a diameter of 3 mm and a length of 5 mm. These granules 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 finally calcined at 870°C in air for 3 hours to obtain the finished catalyst. The catalyst composition is listed in Table 1.

[0075] Comparative Example 2

[0076] Iron oxide red (equivalent to 48.66 parts Fe2O3), iron oxide yellow (equivalent to 24.33 parts Fe2O3), potassium carbonate (equivalent to 12.57 parts K2O), cerium carbonate (equivalent to 10.21 parts CeO2), ammonium molybdate (equivalent to 1.53 parts MoO3), MgO, ZnO, MnO2, TiO2, sodium carboxymethyl cellulose, and hydroxyethyl cellulose were stirred in a kneader for 1.2 hours. Deionized water (22.5% of the total weight of the catalyst raw materials) was added, and the mixture was kneaded for 40 minutes. The extruder was then extruded into particles with a diameter of 3 mm and a length of 5 mm. The particles were first dried in a 40°C heating and humidification equipment for 8 hours, with the humidity controlled at 65%. Then, they were dried in a 90°C oven for 8 hours, calcined at 400°C for 8 hours, and finally calcined in air at 870°C for 3 hours to obtain the finished catalyst. The catalyst composition is listed in Table 1.

[0077] Comparative Example 3

[0078] Iron oxide red (equivalent to 48.66 parts Fe2O3), iron oxide yellow (equivalent to 24.33 parts Fe2O3), potassium carbonate (equivalent to 12.57 parts K2O), ammonium molybdate (equivalent to 1.53 parts MoO3), MgO, ZnO, MnO2, TiO2, sodium carboxymethyl cellulose, and hydroxyethyl cellulose were mixed in a kneader for 1.2 hours. Then, 10.21 parts... The cerium nitrate in CeO2 was dissolved in water at 22.5% of the total weight of the catalyst raw materials. This cerium nitrate solution was then added to the aforementioned dry powder and wet-kneaded for 40 minutes. The resulting extruder was then extruded into particles with a diameter of 3 mm and a length of 5 mm. The particles were first dried in a 40°C heated and humidified environment for 8 hours, with the humidity controlled at 65%. They were then dried in a 90°C oven for 8 hours, calcined at 400°C for 8 hours, and finally calcined in air at 870°C for 3 hours to obtain the finished catalyst. The catalyst composition is listed in Table 1.

[0079] Table 1

[0080]

[0081] Note: In Table 1, W represents the percentage of the total mass of the added soluble cerium source (cerium nitrate or cerium ammonium nitrate) as calculated based on CeO2.

[0082] Catalyst performance testing:

[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 incubated at atmospheric pressure and a liquid hourly space velocity (LHSV) of 0.32 h⁻¹.-1 The activity was evaluated at 640℃ and a water vapor / ethylbenzene (weight ratio) of 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 this application obtained dehydrogenation catalysts with low bulk density and high mechanical strength by adjusting the form of cerium source addition, and have high styrene selectivity in the ethylbenzene dehydrogenation to styrene reaction.

[0089] The technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made in accordance with the technical solutions of the present invention fall within the protection scope of the present invention.

Claims

1. A dehydrogenation catalyst, wherein the chemical composition of the catalyst comprises, by weight percentage: (a) 70-82% Fe2O3; (b) 7-14% K2O; (c) 8-14% CeO2; (d) 0.5~2% MoO3; (e) 0.5~3.5% MgO; (f) 0.1~2% ZnO; (g) 0.01~0.5% MnO2 and / or TiO2; Potassium ferrate (KFe) in the catalyst 11 O 17 The grain size is 50~70nm; The catalyst has a bulk density of 1.26~1.28 g / mL. The mechanical strength of the catalyst is 250.2~260 N / cm; The method for preparing the dehydrogenation catalyst includes the following steps: (1) Mix the iron source, potassium source, first cerium source, molybdenum source, magnesium source, zinc source, manganese source and / or titanium source with the binder to obtain dry powder; (2) The solution containing the second cerium source is mixed with the dry powder, the pH value is adjusted, and the mixture is wet-kneaded, shaped, dried and calcined to obtain the dehydrogenation catalyst; The mass of the second cerium source accounts for 35% to 45% of the total mass of the first and second cerium sources; The second cerium source is a water-soluble cerium source.

2. The dehydrogenation catalyst according to claim 1, characterized in that, The chemical composition of the catalyst, by weight percentage, comprises: (a) 70-75% Fe2O3; (b) 10-14% K₂O; (c) 8-12% CeO2; (d) 1-2% MoO3; (e) 1-2% MgO; (f) 0.5~2% ZnO; (g) 0.05~0.3% MnO2; (h) 0.01~0.1% TiO2.

3. A method for preparing the dehydrogenation catalyst according to any one of claims 1 to 2, comprising the following steps: (1) Mix the iron source, potassium source, first cerium source, molybdenum source, magnesium source, zinc source, manganese source and / or titanium source with the binder to obtain dry powder; (2) The solution containing the second cerium source is mixed with the dry powder, the pH value is adjusted, and the mixture is wet-kneaded, shaped, dried and calcined to obtain the dehydrogenation catalyst.

4. The method according to claim 3, 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 cerium ammonium nitrate; and / or, The second cerium source is selected from at least one of cerium nitrate, cerium acetate, and cerium ammonium nitrate.

5. The method according to claim 3, characterized in that, 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; and / or, The binder includes at least two of methylcellulose, sodium carboxymethylcellulose, hydroxypropyl methylcellulose, and hydroxyethylcellulose.

6. The method according to claim 3, characterized in that, The binder includes sodium carboxymethyl cellulose and hydroxyethyl cellulose.

7. The method according to claim 6, characterized in that, The mass ratio of sodium carboxymethyl cellulose to hydroxyethyl cellulose is (2-5):

1.

8. The method according to claim 3, 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, the mass percentage of the iron source (calculated as Fe2O3) is 70-82%, the mass percentage of the potassium source (calculated as K2O) is 7-14%, the sum of the mass percentages of the first and second cerium sources (calculated as CeO2) is 8-14%, the mass percentage of the molybdenum source (calculated as MoO3) is 0.5-2%, the mass percentage of the magnesium source (calculated as MgO) is 0.5-3.5%, the mass percentage of the zinc source (calculated as ZnO) is 0.1-2%, the mass percentage of the manganese source (calculated as MnO2) is 0-0.5%, and the mass percentage of the titanium source (calculated as TiO2) is 0-0.5%.

9. The method according to claim 3, characterized in that, In step (2), the pH value is adjusted to 7-9; and / or the drying includes: 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.

10. The method according to claim 3, characterized in that, Adjust the pH value using alkaline or acidic substances.

11. The method according to claim 10, characterized in that, The alkaline substance includes urea and / or ammonia, and the acidic substance includes oxalic acid and / or acetic acid.

12. The use of the dehydrogenation catalyst according to any one of claims 1 to 2 or the dehydrogenation catalyst prepared by the method according to any one of claims 3 to 11 in the dehydrogenation of ethylbenzene to styrene.

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