Aromatization fluidized bed catalyst and preparation method thereof

Abstract

The present invention discloses an aromatization fluidized bed catalyst and a preparation method thereof. The aromatization fluidized bed catalyst of the present invention comprises the following components: a) 0.5% to 20% of at least one selected from oxides of a first metal element; b) 0.5% to 15% of an oxide selected from at least one selected from P, B, Si, a second metal element, a rare earth element, or a precious metal element; c) 30% to 60% selected from a molecular sieve; d) 10% to 30% selected from a binder component; and e) 20% to 65% selected from modified kaolin; wherein the specific surface area of ​​the modified kaolin is 25 to 100 m 2 The aromatization fluidized bed catalyst has the advantages of low attrition index and high aromatics yield.

Description

Technical Field

[0001] The invention belongs to the field of aromatization catalysts, and particularly relates to an aromatization fluidized bed catalyst and a preparation method thereof. Background Art

[0002] Ethylene, propylene, and aromatics are the three most important basic organic chemical raw materials. Ethylene and propylene are primarily derived from the catalytic cracking and steam cracking processes of petroleum products, while aromatics are primarily derived from the catalytic reforming of petroleum products and the extraction of pyrolysis gasoline, a by-product of steam cracking.

[0003] The production of olefins or aromatics from oxygenates is a highly exothermic reaction. Furthermore, catalysts are prone to rapid deactivation due to carbon deposition. Compared to traditional fixed-bed reactors, fluidized-bed reactors can rapidly remove reaction heat and enable rapid catalyst regeneration. Consequently, petrochemical companies, universities, and research institutions around the world have developed various technologies for producing olefins or aromatics from oxygenates using fluidized-bed reactors.

[0004] CN101244969A discloses a device and method for continuous aromatization and catalyst regeneration. The catalyst used is a molecular sieve catalyst containing silicon, aluminum and phosphorus components modified with metals such as Zn, Ag, Mo, Pt and Au. The yield of aromatics is greater than 70%, and the BTX selectivity is greater than 55%.

[0005] CN104437594A discloses a low-wear methanol to aromatics fluidized bed catalyst and its preparation method. The catalyst used in the catalyst comprises the following components by weight percentage: 1) 20.0-55.0% kaolin; 2) 10.0-25.0% binder; 3) 0.2-15.0% phosphorus oxide; 4) 0.1-10.0% metal element oxide; 5) 25.0-60.0% ZSM-5 molecular sieve. The phosphorus oxide is added to the catalyst during the preparation of the slurry used for catalyst spray drying, and the technical solution of the catalyst and its preparation method effectively reduces the wear of the catalyst. The kaolin used in the catalyst is conventional kaolin, and the specific surface area is usually less than 20m 2 / g.

[0006] CN109701622A discloses a fluidized bed catalyst for methanol to aromatics. The catalyst uses aluminum hydroxychloride with good bonding properties or a mixture of aluminum hydroxychloride and acidic silica sol as a molding binder. The molecular sieve, binder and structural reinforcing agent are mixed and sprayed into a mold, and then impregnated with an active metal to obtain the fluidized bed catalyst for methanol to aromatics.

[0007] Therefore, the prior art generally prepares aromatization fluidized bed catalysts with low attrition index by adding a binder with better adhesion or by adding additional phosphorus oxides. Developing new aromatization fluidized bed catalysts with low attrition index and preparation methods thereof are urgently needed in the art. Summary of the Invention

[0008] The present invention addresses the technical problems of high attrition index and low total aromatic yield of existing aromatization fluidized bed catalysts, and provides an aromatization fluidized bed catalyst and a preparation method thereof. The aromatization fluidized bed catalyst has the advantages of low attrition index and high aromatic yield.

[0009] The first aspect of the present invention provides an aromatization fluidized bed catalyst comprising the following components:

[0010] a) 0.5% to 20%, preferably 2% to 10% of at least one selected from the first metal element oxide;

[0011] b) 0.5% to 15%, preferably 2% to 8% of an oxide of at least one selected from P, B, Si, a second metal element, a rare earth element or a noble metal element;

[0012] c) 30% to 60% selected from molecular sieves;

[0013] d) 10% to 30% selected from the binder component;

[0014] e) 20% to 65%, preferably 35% to 55% selected from modified kaolin;

[0015] The specific surface area of ​​the modified kaolin is 25-100 m 2 / g, preferably 40~80m 2 / g.

[0016] Furthermore, the first metal element is selected from at least one of Zn, Ga, Mo, and W. The second metal element is selected from at least one of Fe, Co, Mn, and Ni.

[0017] Furthermore, the rare earth element is preferably at least one of La or Ce, and the noble metal element is preferably at least one of Ag, Pt or Pd.

[0018] Furthermore, the molecular sieve comprises at least one of ZSM-5 and ZSM-11 molecular sieves, and has a SiO2 / Al2O3 molar ratio of 10 to 300.

[0019] Furthermore, the binder component is at least one of SiO2, Al2O3, TiO2 or ZrO2.

[0020] Furthermore, the modified kaolin is alkali-treated kaolin. The specific treatment method is: treating kaolin with an alkali solution at 20-99°C for 0.5-96 hours, with a liquid-to-solid mass ratio of 0.5-10, and then washing and drying to obtain the modified kaolin.

[0021] Furthermore, preferably, the kaolin is treated with an alkaline solution at 60-90° C. for 12-48 hours.

[0022] Furthermore, the alkaline solution is a solution of at least one of NaOH, KOH, Na2CO3, K2CO3 or a quaternary ammonium base (such as tetraethylammonium hydroxide), and has a molar concentration of 0.05 to 5 mol / L.

[0023] A second aspect of the present invention provides a method for preparing an aromatization fluidized bed catalyst, comprising the following steps:

[0024] (1) Preparation of modified kaolin;

[0025] (2) mixing the modified kaolin obtained in step (1) with a molecular sieve, a binder, and water, spray-forming the mixture, and calcining the mixture to obtain a carrier;

[0026] (3) The support obtained in step (2) is impregnated with an aqueous solution of a soluble precursor containing an element selected from a) and b) or its oxide, and then dried and calcined to obtain an aromatization fluidized bed catalyst.

[0027] Furthermore, in step (2), the molding is performed by spray molding. The spray molding produces a granular carrier having an average particle size of 55 to 120 microns. In step (2), the calcination conditions are 450 to 680° C. for 1 to 48 hours.

[0028] Furthermore, in step (3), the drying condition is 60-240° C. for 1-48 hours, and the roasting condition is 450-680° C. for 1-48 hours.

[0029] The third aspect of the present invention provides an application of an aromatization fluidized bed catalyst.

[0030] Furthermore, the application is: using oxygen-containing compounds as raw materials, at a reaction temperature of 370-650°C, a reaction pressure of 0.01-4.0 MPa, and a weight space velocity of the oxygen-containing compounds of 0.1-10.0 h -1 Under the conditions of , the raw material passes through the catalyst bed and contacts with the catalyst described in the first aspect or the catalyst prepared by the method described in the second aspect to react to generate products mainly composed of aromatic hydrocarbons.

[0031] Furthermore, the oxygen-containing compound is at least one of alcohol, ether, ketone, acid and ester compounds, preferably at least one of alcohol or ether compounds, such as methanol and dimethyl ether.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] In the composition of aromatization fluidized bed catalyst, the existing technology uses conventional kaolin, which has a low specific surface area, usually not exceeding 20m 2 / g. To date, methods for improving catalyst wear resistance have generally been to add binders (such as alumina and silica) or incorporate phosphorus oxides into the carrier. There is no literature demonstrating that kaolin modification improves aromatization performance. The inventors of the present invention have taken a different approach, employing a specific modified kaolin. They discovered that combining this modified kaolin with other components not only reduces the catalyst's wear index but also significantly improves the aromatics yield of oxygenate-to-aromatics catalysts. DETAILED DESCRIPTION

[0034] To make the present invention easier to understand, the present invention will be further described in detail below with reference to the following examples. These examples are merely illustrative and are not intended to limit the scope of application of the present invention. The raw materials or components used in the present invention can be obtained by commercial routes or conventional methods unless otherwise specified.

[0035] In the present invention, the attrition index of the catalyst is tested using a fluidized bed attrition tester manufactured by Vinci, Italy, and the testing method adopts the international standard ASTM-D5757 of the American Society for Materials.

[0036] In the present invention, the specific surface area of ​​the sample is measured as follows:

[0037] The analysis was performed using a Micromeritics TriStar 3000 multi-channel physical adsorption instrument operating at -196°C. The samples were vacuum degassed at 240°C for 4 hours before measurement. The specific surface area of ​​the molecular sieves was calculated according to the Brunauer-Emmett-Teller (BET) model.

[0038] In the present invention, the total aromatics yield (carbon basis) of the catalyst is defined as the ratio of the total mass of the aromatic products excluding water generated by the reaction to the weight of all hydrocarbons excluding water in the aromatization products. Example 1

[0039] Kaolin KL0 (specific surface area 15.1m 2 / g) was treated with 0.2 mol / L NaOH solution at 45°C and a liquid-to-solid mass ratio of 2 for 48 hours, followed by washing and drying at 120°C for 8 hours to obtain alkali-treated kaolin BE1. The specific surface area of ​​kaolin BE1 was 35.3 m 2 / g.

[0040] 300 g of ZSM-5 molecular sieve (SiO2 / Al2O3 molar ratio of 40), 952.3 g of alumina sol (containing 21 wt% Al2O3), 400 g of kaolin BE1, and 3000 g of water were mixed and spray-formed to produce spray particles SP1 with an average particle size of 72.2 μm. SP1 was calcined at 550°C for 4 h to obtain the support ZT1.

[0041] 180 g of carrier ZT1 was impregnated with 135 g of an aqueous solution containing 36.4 g of zinc nitrate and 16.2 g of phosphoric acid (mass concentration: 85%). The mixture was then dried at 120°C for 8 h and calcined at 550°C for 4 h to obtain an aromatization fluidized bed catalyst a. The composition of catalyst a is shown in Table 1.

[0042] The evaluation conditions of the catalyst are: 100% methanol as raw material, reaction temperature 480℃, methanol weight space velocity WHSV = 1.0h -1 The reaction pressure was normal pressure. The catalyst evaluation results are shown in Table 2. Example 2

[0043] Take the same untreated kaolin KL0 (specific surface area of ​​15.1m 2 / g) as raw material, treated with a 1.0 mol / L K2CO3 solution at 60°C and a liquid-to-solid ratio of 2 for 48 hours, washed, and dried at 120°C for 8 hours to obtain alkali-treated kaolin BE2. The specific surface area of ​​BE2 was 26.2 m2 by N2 physical adsorption test. 2 / g.

[0044] 300 g of ZSM-5 molecular sieve (SiO2 / Al2O3 molar ratio of 40), 952.3 g of alumina sol (containing 21 wt% Al2O3), 400 g of kaolin BE2, and 3000 g of water were mixed and spray-formed to produce spray particles SP2 with an average particle size of 72.0 μm. SP2 was calcined at 550°C for 4 h to obtain the support ZT2.

[0045] 180 g of carrier ZT2 was impregnated with 135 g of an aqueous solution containing 36.4 g of zinc nitrate and 16.2 g of phosphoric acid (mass concentration: 85%). The mixture was then dried at 120°C for 8 h and calcined at 550°C for 4 h to obtain an aromatization fluidized bed catalyst b. The composition of catalyst b is shown in Table 1.

[0046] The evaluation conditions of the catalyst are: 100% methanol as raw material, reaction temperature 480℃, methanol weight space velocity WHSV = 1.0h -1 The reaction pressure was normal pressure. The catalyst evaluation results are shown in Table 2. Example 3

[0047] Take the same untreated kaolin KL0 (specific surface area of ​​15.1m 2 / g) as raw material, treated with 0.5 mol / L NaOH solution at 45°C with a liquid-to-solid ratio of 2 for 48 hours, washed, and dried at 120°C for 8 hours to obtain alkali-treated kaolin BE3. The specific surface area of ​​BE3 was 50.6 m 2 / g.

[0048] 300 g of ZSM-5 molecular sieve (SiO2 / Al2O3 molar ratio of 40), 952.3 g of alumina sol (containing 20 wt% Al2O3), 400 g of kaolin BE3, and 3000 g of water were mixed and spray-formed to produce spray particles SP3 with an average particle size of 72.8 μm. SP3 was calcined at 550°C for 4 h to obtain the support ZT3.

[0049] 180 g of carrier ZT3 was impregnated with 135 g of an aqueous solution containing 36.4 g of zinc nitrate and 16.2 g of phosphoric acid (mass concentration: 85%). The mixture was then dried at 120°C for 8 h and calcined at 550°C for 4 h to obtain an aromatization fluidized bed catalyst C. The composition of catalyst C is shown in Table 1.

[0050] The evaluation conditions of the catalyst are: 100% methanol as raw material, reaction temperature 480℃, methanol weight space velocity WHSV = 1.0 hour -1 The reaction pressure was normal pressure. The catalyst evaluation results are shown in Table 2. Example 4

[0051] Take the same untreated kaolin KL0 (specific surface area of ​​15.1m 2 / g) as raw material, treated with 0.8 mol / L KOH solution at 60°C with a liquid-to-solid ratio of 2 for 48 hours, washed, and dried at 120°C for 8 hours to obtain alkali-treated kaolin BE4. The specific surface area of ​​BE4 was 69.6 m 2 / g.

[0052] 300 g of ZSM-5 molecular sieve (SiO2 / Al2O3 molar ratio of 40), 952.3 g of alumina sol (containing 20 wt% Al2O3), 400 g of kaolin BE4, and 3000 g of water were mixed and spray-formed to produce spray particles SP4 with an average particle size of 72.9 μm. SP4 was calcined at 550°C for 4 h to produce the support ZT4.

[0053] 180 g of carrier ZT4 was impregnated with 135 g of an aqueous solution containing 36.4 g of zinc nitrate and 16.2 g of phosphoric acid (mass concentration: 85%). The mixture was then dried at 120°C for 8 h and calcined at 550°C for 4 h to obtain aromatization fluidized bed catalyst d. The composition of catalyst d is shown in Table 1.

[0054] The evaluation conditions of the catalyst are: 100% methanol as raw material, reaction temperature 480℃, methanol weight space velocity WHSV = 1.0h -1 The reaction pressure was normal pressure. The catalyst evaluation results are shown in Table 2. Example 5

[0055] The alkali-treated kaolin BE4 from Example 4 was used as the kaolin raw material. 480 g of ZSM-5 molecular sieve (SiO2 / Al2O3 molar ratio of 60), 714.3.3 g of alumina sol (containing 20 wt% Al2O3), 250 g of kaolin BE4, and 3000 g of water were mixed uniformly and spray-formed to produce spray particles SP5 with an average particle size of 72.5 μm. SP5 was calcined at 550°C for 4 h to obtain the carrier ZT5.

[0056] 180 g of carrier ZT5 was impregnated with 150 g of an aqueous solution containing 73.4 g of gallium nitrate and 10.6 g of lanthanum nitrate, and then dried at 120° C. for 8 h and calcined at 550° C. for 4 h to obtain an aromatization fluidized bed catalyst e. The composition of catalyst e is shown in Table 1.

[0057] The evaluation conditions of the catalyst are: 100% methanol as raw material, reaction temperature 480℃, methanol weight space velocity WHSV = 1.0h -1 The reaction pressure was normal pressure. The catalyst evaluation results are shown in Table 2. Example 6

[0058] The alkali-treated kaolin BE4 from Example 4 was used as the kaolin raw material. 250 g of ZSM-5 molecular sieve (SiO2 / Al2O3 molar ratio of 25), 250 g of silica sol (containing 20 wt% SiO2), 550 g of kaolin BE4, and 2900 g of water were mixed uniformly and spray-formed to produce spray particles SP6 with an average particle size of 72.4 μm. SP6 was calcined at 550°C for 4 h to obtain the carrier ZT6.

[0059] 190 g of carrier ZT6 was impregnated with 120 g of an aqueous solution containing 9.8 g of ammonium octamolybdate and 2.1 g of chloroplatinic acid, and then dried at 120° C. for 8 h and calcined at 550° C. for 4 h to obtain an aromatization fluidized bed catalyst f. The composition of catalyst f is shown in Table 1.

[0060] The evaluation conditions of the catalyst are: 100% methanol as raw material, reaction temperature 480℃, methanol weight space velocity WHSV = 1.0h -1 The reaction pressure was normal pressure. The catalyst evaluation results are shown in Table 2.

[0061] Comparative Example 1

[0062] Take the same untreated kaolin KL0 (specific surface area of ​​15.1m 2 / g) as raw materials, and catalyst X1 was prepared in a manner similar to Example 1:

[0063] 300 g of ZSM-5 molecular sieve (SiO2 / Al2O3 molar ratio of 40), 952.3 g of aluminum sol (containing 20 wt% Al2O3), 400 g of kaolin KL0, and 3000 g of water were mixed and spray-formed to produce spray particles SP11 with an average particle size of 72 μm. SP11 was calcined at 550°C for 4 h to obtain the support DZT11.

[0064] 180 g of the DZT11 carrier was impregnated with 135 g of an aqueous solution containing 36.4 g of zinc nitrate and 16.2 g of phosphoric acid (85% by mass). The mixture was then dried at 120°C for 8 hours and calcined at 550°C for 4 hours to produce aromatization fluidized bed catalyst X. The composition of catalyst X is shown in Table 1. Catalyst X was evaluated under the same conditions as in Example 1. The catalyst evaluation results are shown in Table 2.

[0065] Comparative Example 2

[0066] Take the same untreated kaolin KL0 (specific surface area of ​​15.1m 2 / g) as raw material, treated with a 2.0 mol / L KOH solution at 150°C with a liquid-to-solid ratio of 2 in a sealed reactor for 48 hours, washed, and dried at 120°C for 8 hours to obtain alkali-treated kaolin BE12. The specific surface area of ​​BE12 was 112 m2 by N2 physical adsorption test. 2 / g.

[0067] 300 g of ZSM-5 molecular sieve (SiO2 / Al2O3 molar ratio of 40), 952.3 g of alumina sol (containing 21 wt% Al2O3), 400 g of kaolin BE12, and 3000 g of water were mixed and spray-formed to produce spray particles of SP12 with an average particle size of 72 μm. The SP12 was calcined at 550°C for 4 h to produce the support DZT12.

[0068] 180 g of the DZT12 carrier was impregnated with 135 g of an aqueous solution containing 36.4 g of zinc nitrate and 16.2 g of phosphoric acid (85% by mass). The catalyst was then dried at 120°C for 8 h and calcined at 550°C for 4 h to produce aromatization fluidized bed catalyst Y. The composition of catalyst Y is shown in Table 1. Catalyst Y was evaluated under the same conditions as in Example 1. The catalyst evaluation results are shown in Table 2.

[0069] Table 1

[0070] Example catalyst Catalyst weight composition 1 a <![CDATA[5%ZnO:5%P2O5:30%ZSM-5:20%Al2O3:40%BE1]]> 2 b <![CDATA[5%ZnO:5%P2O5:30%ZSM-5:20%Al2O3:40%BE2]]> 3 c <![CDATA[5%ZnO:5%P2O5:30%ZSM-5:20%Al2O3:40%BE3]]> 4 d <![CDATA[5%ZnO:5%P2O5:30%ZSM-5:20%Al2O3:40%BE4]]> 5 e <![CDATA[10%Ga2O3:2%La2O3:48%ZSM-5:15%Al2O3:25%BE4]]> 6 f <![CDATA[4.5%MoO3:0.5Pt%:25%ZSM-5:10%SiO2:55%BE4]]> Comparative Example 1 X <![CDATA[5%ZnO:5%P2O5:30%ZSM-5:20%Al2O3:40% KL0]]> 2 Y <![CDATA[5%ZnO:5%P2O5:30%ZSM-5:20%Al2O3:40%BE12]]>

[0071] Table 2

[0072] Example catalyst Wear index / % Total aromatic yield / % 1 a 5.2 63.5 2 b 4.7 63.2 3 c 4.3 66.4 4 d 3.5 68.6 5 e 6.0 70.7 6 f 4.5 66.5 Comparative Example 1 X 7.8 60.7 2 Y 9.5 62.2

[0073] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation of the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein. On the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. An aromatization fluidized bed catalyst, characterized in that: The catalyst comprises the following components: a) 0.5% to 20% of at least one selected from the first metal element oxide; b) 0.5% to 15% of an oxide of at least one selected from P, B, Si, a second metal element, a rare earth element, or a noble metal element; c) 30% to 60% selected from molecular sieves; d) 10% to 30% selected from the binder component; e) 20% to 65% selected from modified kaolin; The specific surface area of ​​the modified kaolin is 25-100 m 2 / g; The modified kaolin is alkali-treated kaolin; the specific treatment method is: treating the kaolin with an alkali solution at 20-99°C for 0.5-96 hours, with a liquid-to-solid mass ratio of 0.5-10, and then washing and drying to obtain the modified kaolin; the molar concentration of the alkali solution is 0.05-5 mol / L; The first metal element is selected from at least one of Zn, Ga, Mo, and W; the second metal element is selected from at least one of Fe, Co, Mn, and Ni; The molecular sieve comprises at least one of ZSM-5 or ZSM-11 molecular sieves; the SiO2 / Al2O3 molar ratio of the molecular sieve is 10-300.

2. The catalyst according to claim 1, characterized in that: The catalyst comprises the following components: a) 2% to 10% of at least one selected from the first metal element oxide; b) 2% to 8% of an oxide of at least one selected from P, B, Si, a second metal element, a rare earth element, or a noble metal element; c) 30% to 60% selected from molecular sieves; d) 10% to 30% selected from the binder component; e) 35% to 55% selected from modified kaolin; The specific surface area of ​​the modified kaolin is 40-80 m 2 / g.

3. The catalyst according to claim 1 or 2, characterized in that: The rare earth element is at least one of La and Ce; the noble metal element is at least one of Ag, Pt and Pd.

4. The catalyst according to claim 1 or 2, characterized in that: The binder component is at least one of SiO2, Al2O3, TiO2 or ZrO2.

5. A method for preparing a catalyst according to any one of claims 1 to 4, characterized in that: The following steps are involved: (1) Preparation of modified kaolin; (2) mixing the modified kaolin obtained in step (1) with a molecular sieve, a binder, and water, spray-forming the mixture, and calcining the mixture to obtain a carrier; (3) The support obtained in step (2) is impregnated with an aqueous solution of a soluble precursor containing the substances in a) and b), and then dried and calcined to obtain an aromatization fluidized bed catalyst.

6. The method according to claim 5, characterized in that: In step (2), the average particle size of the carrier is 55 to 120 microns.

7. The method according to claim 5, characterized in that: In step (2), the calcination condition is 450-680° C. for 1-48 hours.

8. The method according to claim 5, characterized in that: In step (3), the drying condition is 60-240° C. for 1-48 hours, and the roasting condition is 450-680° C. for 1-48 hours.

9. Use of the catalyst according to any one of claims 1 to 4 or the catalyst prepared by the method according to any one of claims 5 to 8 in an aromatization fluidized bed.

10. The use according to claim 9, characterized in that: Using oxygen-containing compounds as raw materials, the reaction temperature is 370~650℃, the reaction pressure is 0.01~4.0MPa, and the weight space velocity of oxygen-containing compounds is 0.1~10.0h -1 Under the conditions of , the raw material contacts the catalyst through the catalyst bed and reacts to generate products mainly composed of aromatic hydrocarbons.