A method for preparing and using a co-catalyst

Abstract

The application discloses a preparation method and application of a cocatalyst, and belongs to the technical field of catalytic material preparation. The preparation method of the cocatalyst comprises the following steps: 1) uniformly mixing a carrier, a pore-forming agent, a binder and water to obtain a slurry, and roasting the slurry after shaping to obtain a microsphere carrier; 2) mixing the microsphere carrier with a modifier, a mineralizer and water, and performing a crystallization reaction under sealed conditions to obtain a microsphere carrier loaded with rare earth phosphate crystals, and roasting to obtain the cocatalyst; the modifier is selected from rare earth salts or rare earth oxides, and the mineralizer is selected from phosphoric acid or ammonium phosphate. According to the preparation method, the rare earth phosphate crystals are generated on the microsphere carrier by using a crystal growth hydrothermal method, and the cocatalyst with high dispersion and strong stability of active part rare earth phosphate is obtained by roasting and solidification, so that the cocatalyst has excellent vanadium and sulfur capturing capacity, and can significantly improve the catalytic activity of a main catalyst in a catalytic cracking reaction.

Description

Technical Field

[0001] This invention relates to the technical field of catalytic material preparation, and more particularly to a method for preparing and applying a co-catalyst. Background Technology

[0002] With the rapid development of the global economy, people's consumption of gasoline and diesel resources is increasing day by day. Furthermore, with the dwindling oil resources, traditional catalytic cracking units will face the problem of heavier and lower-quality feedstock. A particularly noticeable issue is the high content of heavy metals and sulfur in the feedstock, which will pose a severe challenge to the equipment and the catalysts used.

[0003] In catalytic cracking, vanadium metal can penetrate the molecular sieve, occupying active sites and affecting catalyst activity. Under high-temperature conditions, molten vanadium metal can also react with aluminum active sites on the catalyst to form aluminum vanadate, which damages the crystal structure of the molecular sieve and leads to a permanent loss of catalyst activity. Furthermore, vanadium metal can catalyze dehydrogenation reactions, resulting in poorer product distribution in the catalytic cracking unit, decreased yield of light oil, and increased low-value-added dry gas.

[0004] Vanadium metal tends to migrate towards components with lower electronegativity. Rare earth elements, with their lower electronegativity, are more prone to vanadium aggregation, forming high-melting-point substances that can capture it, effectively preventing vanadium migration and reducing its destructive effect on the catalyst. Sulfur in the raw materials, after reaction, produces a large amount of hydrogen sulfide gas, increasing dry gas production. However, hydrogen sulfide is highly toxic, causing fatal damage to the environment and human health. Furthermore, some sulfur enters subsequent gasoline and diesel fuels, affecting product quality and increasing the burden on subsequent processing.

[0005] Patent CN1226464 uses kaolin co-modified with transition metal oxides and phosphorus-containing compounds as the active component of a vanadium-trapping agent. The resulting main catalyst exhibits high activity, low coking, and strong resistance to heavy metal vanadium contamination. Patent CN109092280A uses surfactants to modify attapulgite, then mixes it with magnesium oxide and a binder to prepare a vanadium-trapping agent. This vanadium-trapping agent has a larger specific surface area, typically reaching 200 m². 2 / g or more, and wear less than 1.0%h -1 It exhibits good vanadium capture ability and wear resistance. Patent CN1334314A first prepares microspheres through an "in-situ crystallization method," and then prepares a vanadium-capturing agent containing modified Y-type zeolite through ammonium exchange and rare earth exchange. The above-mentioned vanadium-capturing agents, which directly use rare earth or alkaline earth metals to capture vanadium, not only easily clog catalyst pores, but also cause increased coking due to excessive rare earth, or reduced catalyst acidity due to excessive alkaline earth, thus leading to decreased catalytic activity. Moreover, these vanadium-capturing agents failed to demonstrate vanadium capture ability in high-sulfur environments.

[0006] In summary, to overcome the shortcomings of existing technologies, it is of great significance to develop a catalyst for catalytic cracking that has both vanadium and sulfur capture capabilities. Summary of the Invention

[0007] In view of this, the technical problem to be solved by the present invention is to provide a method for preparing a co-catalyst and its application. The co-catalyst prepared by the method has excellent vanadium and sulfur capture capabilities, and can significantly improve the catalytic activity of the main catalyst in catalytic cracking reactions.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] This invention provides a method for preparing a co-catalyst, comprising the following steps:

[0010] 1) A slurry is obtained by uniformly mixing the carrier, pore-forming agent, binder and water. The slurry is then calcined after molding to obtain microsphere carriers.

[0011] 2) The microsphere carrier is mixed with a modifier, a mineralizer and water, and a crystallization reaction is carried out under sealed conditions to obtain a microsphere carrier loaded with rare earth phosphate crystals. The carrier is then calcined to obtain a co-catalyst.

[0012] The modifier is selected from rare earth salts or rare earth oxides, and the mineralizer is selected from phosphoric acid or ammonium phosphate.

[0013] The ammonium phosphate salts include, but are not limited to, one or more of diammonium hydrogen phosphate, ammonium dihydrogen phosphate, and ammonium phosphate.

[0014] Preferably, the mineralizing agent is phosphoric acid or ammonium dihydrogen phosphate.

[0015] In the above preparation method, the rare earth salt includes, but is not limited to, one or more of lanthanum chloride, lanthanum nitrate, cerium chloride, and cerium nitrate. In some specific embodiments of the present invention, lanthanum chloride is preferred.

[0016] The rare earth oxides include, but are not limited to, one or more of lanthanum oxide, cerium oxide, yttrium oxide, and scandium oxide. In some specific embodiments of the present invention, lanthanum oxide is preferred.

[0017] The present invention does not have any special limitation on the mixing method in step 1) above, and can be any mixing method known to those skilled in the art.

[0018] In some specific embodiments of the present invention, high-speed stirring and mixing is preferred.

[0019] In some specific embodiments of the present invention, preferably, after high-speed stirring and mixing, a slurry with a particle size preferably D90<10μm is obtained by ball milling.

[0020] Furthermore, in step 1), the slurry forming is preferably performed using spray forming.

[0021] In the above preparation method, preferably, the slurry is spray-formed and then calcined to obtain the microsphere carrier. The spray-forming utilizes the principle of spray drying to prepare a fluidized slurry containing the microsphere carrier precursor into a microsphere carrier.

[0022] Preferably, the solid content of the spray slurry in the spray molding method of the present invention is 25wt% to 50wt%; more preferably, it is 28wt% to 45wt%. In some specific embodiments of the present invention, it is preferably 38wt%.

[0023] The present invention does not have any special limitation on the mixing method in step 2) above, and can be any mixing method known to those skilled in the art.

[0024] In some specific embodiments of the present invention, impregnation and mixing are preferred.

[0025] The impregnation and mixing process preferably involves impregnating the microsphere carrier in a mixed solution of a modifier and a mineralizer.

[0026] Preferably, the temperature of the crystallization reaction in step 2) of this invention is 100℃~200℃; more preferably, it is 120℃~150℃. In some specific embodiments of this invention, 120℃ is preferred.

[0027] Preferably, the crystallization reaction takes 1 to 12 hours; more preferably, it takes 4 to 8 hours. In some specific embodiments of the present invention, it is preferably 6 hours.

[0028] Preferably, in step 2), the mass ratio of the microsphere carrier to the modifier is 1:(0.01-0.2); more preferably, it is 1:(0.02-0.1).

[0029] Preferably, the mass ratio of the modifier to the mineralizer is 1:(0.2-5); more preferably, it is 1:(0.5-2).

[0030] After the crystallization reaction in step 2) above is completed, post-processing such as filtration, washing, and drying is also included.

[0031] The present invention does not specifically limit the above-described filtration and drying methods, which are methods well known to those skilled in the art.

[0032] The present invention does not have any particular limitation on the washing solution described above, and any washing solution known to those skilled in the art is acceptable.

[0033] Following the aforementioned drying process, calcination is also included. The co-catalyst is solidified by calcining the microsphere support loaded with rare earth phosphate crystals, thereby increasing its strength and yielding a co-catalyst composed of a support and rare earth phosphate. This co-catalyst can significantly improve the catalytic activity of the main catalyst in catalytic cracking reactions.

[0034] Preferably, the roasting temperature in step 2) of this invention is 300℃~600℃; more preferably, it is 450℃.

[0035] Preferably, the roasting time in step 2) is 1 to 3 hours.

[0036] The co-catalyst of this invention comprises the following components, based on a dry basis oxide mass percentage:

[0037] 30%–60% silicon dioxide, 10%–30% aluminum oxide, 1%–20% alkaline earth elements, 1%–10% rare earth elements, and 5%–20% phosphorus.

[0038] Preferably, in step 1), the particle size of the microsphere carrier is 20–150 μm.

[0039] The preferred mass ratio of carrier, pore-forming agent, adhesive and water in step 1) is 1:(0.1-0.5):(0.1-0.3):(2-3); more preferably 1:(0.12-0.35):(0.1-0.28):(2-2.5).

[0040] In some specific embodiments of the present invention, the preferred ratios are 1:0.35:0.19:2.5, 1:0.25:0.28:2.5, 1:0.12:0.1:2, or 1:0.21:0.12:2.1. Preferably, the carrier in step 1) is selected from one or more of kaolin, diatomaceous earth, and attapulgite; more preferably, it is kaolin or diatomaceous earth.

[0041] The microsphere support in the co-catalyst of the present invention has a porous structure, which enables the co-catalyst to simultaneously capture vanadium and sulfur elements, thereby ensuring the catalytic activity of the main catalyst.

[0042] Preferably, the pore-forming agent in step 1) is selected from alkaline earth metal salts.

[0043] The alkaline earth metal salts include, but are not limited to, one or more of the following: alkaline earth metal carbonates, alkaline earth metal bicarbonates, alkaline earth metal nitrates, alkaline earth metal sulfates, alkaline earth metal phosphates, and alkaline earth metal halides.

[0044] Preferably, the alkaline earth metal salt is selected from the carbonates or bicarbonates of alkaline earth metals. In some specific embodiments of the present invention, magnesium carbonate or magnesium bicarbonate is preferred.

[0045] Preferably, the adhesive in step 1) is selected from one or more of aluminum sol, silica sol, water glass, acidified boehmite, and aluminum phosphate; more preferably, it is selected from one or more of aluminum phosphate, aluminum sol, and acidified boehmite.

[0046] Preferably, the roasting temperature in step 1) of this invention is 300℃~800℃; more preferably, it is 400℃~600℃. In some specific embodiments of this invention, 450℃ is preferred.

[0047] Preferably, the roasting time is 1 to 8 hours; more preferably, it is 1 to 4 hours. In some specific embodiments of the present invention, it is preferably 1.5 hours.

[0048] The present invention also provides a catalytic cracking reaction catalyst, comprising a main catalyst and a co-catalyst prepared by the above-described preparation method.

[0049] Preferably, the co-catalyst comprises 0.1 wt% to 5 wt% of the main catalyst; more preferably, it comprises 1 wt% to 4 wt%; and even more preferably, it comprises 3 wt%.

[0050] The present invention also provides a catalytic cracking reaction, wherein the above-mentioned catalytic cracking reaction catalyst is used for the reaction.

[0051] The co-catalyst described in this invention possesses excellent vanadium and sulfur capture capabilities. When used in catalytic cracking reactions, it captures a significant amount of vanadium and sulfur, reducing the loss of the main catalyst and significantly improving catalytic activity. Furthermore, even after multiple regeneration reactions, the co-catalyst still maintains superior vanadium and sulfur capture activity.

[0052] Compared with existing technologies, the preparation method of the co-catalyst provided by this invention includes the following steps: 1) mixing a support, a pore-forming agent, a binder, and water uniformly to obtain a slurry, and then calcining the slurry to obtain a microsphere support; 2) mixing the microsphere support with a modifier, a mineralizer, and water, and carrying out a crystallization reaction under sealed conditions to obtain a microsphere support loaded with rare earth phosphate crystals, and then calcining to obtain the co-catalyst; the modifier is selected from rare earth salts or rare earth oxides, and the mineralizer is selected from phosphoric acid or ammonium phosphate. The preparation method of this invention uses a hydrothermal crystal growth method to generate rare earth phosphate crystals on a microsphere support, and then calcines and solidifies it to obtain a co-catalyst with high dispersion and strong stability of the active rare earth phosphate, thereby enabling the co-catalyst to have excellent vanadium and sulfur capture capabilities, and significantly improving the catalytic activity of the main catalyst in catalytic cracking reactions. Detailed Implementation

[0053] To further illustrate the present invention, the preparation method and application of the co-catalyst provided by the present invention will be described in detail below with reference to the embodiments.

[0054] Example 1

[0055] (1) Preparation of microspheres: Prepare a slurry (solid content 38 wt%) according to the component ratios given in Table 1, and spray-mold it. Add deionized water, binder, carrier, and pore-forming agent to the mixing tank in sequence, stir at high speed until homogeneous, and ball mill until the slurry D90 < 10 micrometers. Spray-mold the slurry to form fluidized spherical carrier microspheres with a particle size of 20–150 micrometers, and the particle size distribution meets the requirements of conventional catalytic cracking. Calcinate the microspheres at 450℃ for 1.5 hours. These are denoted as WQ-1 to WQ-4.

[0056] (2) Preparation of additives: The modifier and mineralizer were dispersed in deionized water according to the specified proportions and mixed evenly. Microspheres (WQ-1 to 4) were respectively loaded into reactors, the prepared solution was added, the reactors were sealed and heated to 120°C, and crystallization reaction was carried out under autogenous pressure for 6 hours. After the reaction was completed, the microspheres were subjected to conventional steps such as filtration, washing, drying, and calcination. In Example 1, the calcination temperature was 450°C and the calcination time was 2 hours to obtain the additives of the present invention (composed of a carrier and rare earth phosphates loaded on its surface), denoted as S-1 to 4.

[0057] (3) Poisoning and Testing: The commercial catalytic cracking main agent, rare earth Y-type molecular sieve-formed catalyst, was aged at 800°C and 100% steam for 17 hours. Then, 3 wt% of the example sample was incorporated, and the catalyst was repeatedly poisoned (60 times) in a fixed fluidized bed reactor, undergoing stripping and regeneration. Samples were taken during this process to determine the MAT activity. The commercial catalytic cracking main agent after aging is denoted as: KB

[0058] (4) Poisoning conditions: 1. Raw materials: straight-run diesel oil + vanadium naphthenate + thiophene (V: 3000ppm; S: 200ppm); 2. Reaction temperature: 520℃; 3. Agent-to-oil ratio: 3; 4. Feed rate: 30g / min.

[0059] (5) Stripping conditions: 1. Steam: 100%; 2. Stripping temperature: 520℃; 3. Steam space velocity: 1h-1; 4. Stripping time: 30min.

[0060] (6) Regeneration conditions: 1. Raw materials: air + steam (5wt% steam); 2. Regeneration temperature: 720℃; 3. Regeneration time: 120min; 4. Regeneration state: complete regeneration.

[0061] (7) Activity determination: The catalyst activity was tested in the MAT device. The reaction feedstock was Dagang straight-run light diesel oil (fraction 235℃~337℃), the reaction temperature was 460℃, the reaction time was 70s, the catalyst loading was 5g, and the oil feed rate was 1.56g.

[0062] Comparative Example 1

[0063] Lanthanum oxide, phosphoric acid, and water were mixed in a specific ratio to form a solution, which was then used to impregnate the carrier microspheres (WQ-3) with an equal volume. After adsorption equilibrium (25℃, more than 12h), the impregnated microspheres were dried (120℃, 12h) and calcined (450℃, 3h) to obtain Comparative Example 1, denoted as DB-1. The composition of the co-catalyst DB-1 in Comparative Example 1 was: SiO2: 47.3%, Al2O3: 21.4%, MgO: 13.4%, P2O5: 8.8%, Re2O3: 6.8%, with a specific surface area of ​​306.8 m². 2 / g, pore volume is 0.53mL / g.

[0064] Table 1. Composition and raw materials of the microspheres in Examples 1-4

[0065]

[0066]

[0067] Table 2 Composition and raw materials of the adjuvants in Examples 1-4

[0068]

[0069] Table 3 Performance of Example and Comparative Samples and Blank (KB) Samples

[0070]

[0071]

[0072] As shown in Table 2, compared with the catalyst promoter prepared in Comparative Example 1, the sample samples S-1 to S-4 of the examples all have higher specific surface area and pore volume. After multiple cycles, the catalyst formed by rare earth Y-type molecular sieves for catalytic cracking with the additives of the examples (after aging) can still maintain high MAT activity. This indicates that the sample samples of the examples can capture more vanadium in a sulfur-containing atmosphere (sulfur-containing poisoning conditions), thereby protecting the activity of the catalytic cracking catalyst.

[0073] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a co-catalyst for catalytic cracking reactions, characterized in that, Includes the following steps: 1) The carrier, pore-forming agent, binder and water are mixed evenly to obtain a slurry. The slurry is then calcined to obtain a microsphere carrier. The carrier is selected from one or more of kaolin, diatomaceous earth and attapulgite. 2) The microsphere carrier is mixed with a modifier, a mineralizer and water, and a crystallization reaction is carried out under sealed conditions to obtain a microsphere carrier loaded with rare earth phosphate crystals. The microsphere carrier is then calcined to obtain a co-catalyst. The modifier is selected from rare earth salts or rare earth oxides, and the mineralizer is selected from phosphoric acid or ammonium phosphate. The roasting temperature in step 1) is 300℃~800℃; the roasting temperature in step 2) is 300℃~600℃; The co-catalyst, by dry basis oxide mass percentage, comprises the following components: 30%~60% silicon dioxide, 10%~30% aluminum oxide, 1%~20% alkaline earth elements, 1%~10% rare earth elements, and 5%~20% phosphorus.

2. The preparation method according to claim 1, characterized in that, The temperature of the crystallization reaction in step 2) is 100℃~200℃; The crystallization reaction takes 1 to 12 hours.

3. The preparation method according to claim 1, characterized in that, The mass ratio of microsphere carrier to modifier in step 2) is 1:(0.01~0.2). The mass ratio of the modifier to the mineralizer is 1:(0.2~5).

4. The preparation method according to claim 1, characterized in that, The roasting time in step 2) is 0.5~6 h.

5. The preparation method according to claim 1, characterized in that, In step 1), the particle size of the microsphere carrier is 20~150 μm.

6. The preparation method according to claim 1, characterized in that, The pore-forming agent in step 1) is selected from alkaline earth metal salts; The adhesive used in step 1) is selected from one or more of aluminum sol, silica sol, water glass, acidified boehmite, and aluminum phosphate.

7. The preparation method according to claim 1, characterized in that, The roasting time is 1 to 8 hours.

8. A catalyst for catalytic cracking reaction, characterized in that, It includes the main catalyst and the co-catalyst prepared by the preparation method according to any one of claims 1 to 7.

9. The catalytic cracking catalyst according to claim 8, characterized in that, The co-catalyst comprises 0.1 wt% to 5 wt% of the main catalyst.

10. A catalytic cracking reaction, characterized in that, The reaction is carried out using the catalytic cracking catalyst as described in claim 8 or 9.

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