A preparation method of a fluid catalytic cracking catalyst

Abstract

The present invention relates to the technical field of petroleum processing and relates to a preparation method of a fluid catalytic cracking catalyst, which specifically comprises the following technological steps: (1) mixing the un-ion-exchanged NaY molecular sieve with a rare earth solution to make a slurry to obtain a rare earth Y molecular sieve slurry; (2) mixing the rare earth Y molecular sieve slurry, clay and a binder, making a slurry, and spray-drying and shaping to obtain catalyst microspheres; (3) calcining the catalyst microspheres at 300-500 °C, and performing an ion exchange reaction on the calcined catalyst microspheres with water, a rare earth salt and polyvinyl alcohol, filtering and drying to obtain the catalyst. In the present invention, the NaY molecular sieve is first slurried with a part of the rare earth solution to improve the ion exchange efficiency; polyvinyl alcohol is added during the ion exchange process of the rare earth salt of the catalyst microspheres to reduce the loss of rare earth ions, thereby reducing the production cost and the pressure of subsequent waste treatment.

Description

Technical Field

[0001] The present invention relates to the technical field of petroleum processing, and relates to a preparation method of a fluid catalytic cracking catalyst. Background Art

[0002] One of the most important refining means in the petroleum refining process is the fluid catalytic cracking technology, and the fluid catalytic cracking catalyst is the core content of the fluid catalytic cracking technology. In order to reduce the sodium oxide content in the catalyst, ammonium salts are generally used in the production process of the fluid catalytic cracking catalyst to perform ion exchange on Na in the catalyst and its active component zeolite molecular sieve. In order to improve the exchange degree of sodium ions, the methods of multiple ammonium exchanges and multiple washings are often adopted. The waste liquids after molecular sieve exchange and catalyst washing are both high-ammonia-nitrogen wastewaters, which increase the investment in ammonia-nitrogen removal equipment and the maintenance and operation costs of enterprises, and increase the production cost and the burden of sewage treatment. Therefore, reducing the production cost and solving the ammonia-nitrogen pollution in the catalyst preparation process are also the key points and difficulties in the development of fluid catalytic cracking catalysts. + CN115634710A discloses a preparation method of a fluid catalytic cracking catalyst without ammonia-nitrogen pollution. The method includes mixing unmodified NaY molecular sieve with a binder, clay and water, beating into a slurry, spray drying and calcining to obtain catalyst microspheres; then, performing steps of ion exchange modification, mild hydrothermal ultrastabilization modification and SiCl4 gas-phase ultrastabilization modification. This method solves the problem of ammonia-nitrogen pollution in the production of fluid catalytic cracking catalysts. However, the use of SiCl4 gas-phase ultrastabilization modification requires an increase in equipment investment, and SiCl4 hydrolyzes in the presence of water to form silica gel and hydrochloric acid. The silica gel is extremely easy to block the pipeline, and the hydrochloric acid greatly damages the equipment and the molecular sieve. At the same time, chlorine has strong corrosiveness and cannot be directly discharged into the atmosphere. It can only be absorbed by water for sewage discharge, which will cause the chlorine content in the sewage to increase rapidly and the waste of chlorine element, and cannot meet the requirements of direct discharge of ammonia-nitrogen wastewater in the existing catalyst production device.

[0003] CN115634710A discloses a preparation method of a fluid catalytic cracking catalyst without ammonia-nitrogen pollution. The method includes mixing unmodified NaY molecular sieve with a binder, clay and water, beating into a slurry, spray drying and calcining to obtain catalyst microspheres; then, performing steps of ion exchange modification, mild hydrothermal ultrastabilization modification and SiCl4 gas-phase ultrastabilization modification. This method solves the problem of ammonia-nitrogen pollution in the production of fluid catalytic cracking catalysts. However, the use of SiCl4 gas-phase ultrastabilization modification requires an increase in equipment investment, and SiCl4 hydrolyzes in the presence of water to form silica gel and hydrochloric acid. The silica gel is extremely easy to block the pipeline, and the hydrochloric acid greatly damages the equipment and the molecular sieve. At the same time, chlorine has strong corrosiveness and cannot be directly discharged into the atmosphere. It can only be absorbed by water for sewage discharge, which will cause the chlorine content in the sewage to increase rapidly and the waste of chlorine element, and cannot meet the requirements of direct discharge of ammonia-nitrogen wastewater in the existing catalyst production device. Summary of the Invention

[0004] Aiming at the problems of high equipment cost and excessive chlorine content in wastewater in the existing preparation method of fluid catalytic cracking catalyst without ammonia-nitrogen pollution, the present invention provides a preparation method of a fluid catalytic cracking catalyst, which does not require additional investment, realizes the goal of direct discharge of wastewater in the preparation process of the fluid catalytic cracking catalyst, and ensures the continuous production of the catalyst in the existing device.

[0005] The present invention provides a preparation method of a fluid catalytic cracking catalyst, which specifically includes the following process steps:

[0006] (1) Mixing and beating unexchanged NaY molecular sieve with a rare earth solution to obtain a rare earth Y molecular sieve slurry;

[0007] (2) Mix the rare earth Y molecular sieve slurry, clay and binder, make a pulp, and obtain catalyst microspheres by spray drying and forming;

[0008] (3) Roast the catalyst microspheres at 300 - 500 °C, and carry out an ion exchange reaction on the roasted catalyst microspheres with water, rare earth salts and polyvinyl alcohol, filter and dry to obtain the catalyst.

[0009] Further, in step (1), the rare earth solution is rare earth nitrate or rare earth chloride, and the rare earth includes at least one of lanthanum, cerium, praseodymium, neodymium, and yttrium.

[0010] Further, in step (1), based on dry basis, NaY molecular sieve : rare earth calculated as RE2O3 = 1 : 0.01 - 0.15.

[0011] Further, in step (1), the content of NaY molecular sieve in the rare earth Y molecular sieve slurry is 100 - 300 g / L.

[0012] Further, in step (1), the temperature of the rare earth Y molecular sieve slurry is 10 - 100 °C, preferably 50 - 90 °C.

[0013] Further, in step (2), based on dry basis, the weight ratio of clay, binder and rare earth Y molecular sieve slurry is (10 - 85) : (5 - 40) : (10 - 70), preferably (20 - 70) : (10 - 30) : (20 - 50).

[0014] Further, in step (2), the clay is selected from one or more of kaolin, montmorillonite, diatomite, halloysite, soapstone, rectorite, sepiolite, attapulgite, hydrotalcite, bentonite.

[0015] Further, in step (2), the binder is one or more of a silicon-based binder, an aluminum-based binder or a silicon-aluminum binder; the silicon-based binder is silica sol; the aluminum-based binder is one or more of aluminum sol, pseudoboehmite, aluminum gel; the silicon-aluminum binder is silica-alumina sol or silica-alumina gel.

[0016] Further, in step (3), the temperature of the ion exchange reaction is 20 - 60 °C, preferably 25 - 45 °C, the exchange time is 10 - 120 minutes, and the rare earth salt is rare earth chloride and / or rare earth nitrate.

[0017] Further, in step (3), based on dry basis, the roasted catalyst microspheres : rare earth salt calculated as RE2O3 : polyvinyl alcohol : water = 1 : (0.01 - 0.15) : (0.001 - 0.05) : (2 - 20).

[0018] The beneficial effects of the present invention are as follows:

[0019] 1. In the preparation method of the fluid catalytic cracking catalyst provided by the present invention, the NaY molecular sieve is first slurried with a part of the rare earth solution, so that the rare earth ions are in full contact with the NaY molecular sieve for pre-exchange, improving the ion exchange efficiency. Polyvinyl alcohol is added during the ion exchange of the rare earth salt of the catalyst microspheres. The polyvinyl alcohol contains a large number of hydroxyl groups, which can form complexes with the rare earth ions, reducing the loss of rare earth ions, thereby achieving the reduction of the sodium oxide content in the catalyst to a relatively low level, making the utilization rate of the rare earth salt relatively high, thus reducing the production cost and the pressure of subsequent waste treatment.

[0020] 2. The preparation method of the fluid catalytic cracking catalyst provided by the present invention has no ammonia-nitrogen pollution throughout the preparation process, and can obtain a fluid catalytic cracking catalyst with a relatively low sodium oxide content, effectively solving the ammonia-nitrogen pollution problem urgently to be solved in the production of fluid catalytic cracking catalysts. Detailed implementation manners

[0021] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0022] Raw material sources:

[0023] NaY molecular sieve: industrial product, produced by Lanzhou Petrochemical Company, with a crystallinity of 94%, a silica-alumina ratio of 5, a Na2O content of 14.3%, and a loss on ignition of 15%; kaolin (loss on ignition of 19%), halloysite (loss on ignition of 21%), montmorillonite (loss on ignition of 17%), silica sol (solid content of 30%), pseudo-boehmite (loss on ignition of 30%) and aluminum sol (solid content of 20%) are all from Lanzhou Petrochemical Company; lanthanum chloride, cerium nitrate, hydrochloric acid, polyvinyl alcohol: analytical pure, all are chemical reagents.

[0024] Specific analysis methods:

[0025] (1) Sodium oxide and rare earth content of the catalyst: analyzed by X-ray fluorescence spectrometry.

[0026] (2) Rare earth content in the filtrate: detected by ICP (Inductive Coupled Plasma Emission Spectrometer).

[0027] Example 1

[0028] Add 30 g of NaY molecular sieve, 4.5 g of lanthanum chloride and 150 g of water to a reaction kettle, stir evenly, heat up to 60 °C, then add 76 g of kaolin and 50 g of aluminum sol, mix and make a slurry, and spray dry to obtain catalyst microspheres; roast 100 g of the above catalyst microspheres at 300 °C, add 500 g of water, 12 g of lanthanum chloride and 1.3 g of polyvinyl alcohol, heat up to 20 °C, stir for 2 hours, filter to collect the filtrate, and dry the filter cake to obtain the finished catalyst S1.

[0029] Example 2

[0030] Add 12 g of NaY molecular sieve, 3 g of cerium nitrate and 100 g of water to a reaction kettle, stir evenly, heat up to 100 °C, then add 105 g of halloysite and 25 g of aluminum sol, mix and make a slurry, and spray dry to obtain catalyst microspheres; roast 100 g of the above catalyst microspheres at 400 °C, add 200 g of water, 1.5 g of lanthanum chloride and 0.1 g of polyvinyl alcohol, heat up to 40 °C, stir for 10 minutes, filter to collect the filtrate, and dry the filter cake to obtain the finished catalyst S2.

[0031] Example 3

[0032] Add 82 g of NaY molecular sieve, 1.1 g of lanthanum chloride and 230 g of water to a reaction kettle, stir evenly, heat up to 10 °C, then add 15 g of kaolin and 87 g of aluminum sol, mix and make a slurry, and spray dry to obtain catalyst microspheres; roast 100 g of the above catalyst microspheres at 500 °C, add 500 g of water, 22.5 g of lanthanum chloride and 5 g of polyvinyl alcohol, heat up to 60 °C, stir for 1 hour, filter to collect the filtrate, and dry the filter cake to obtain the finished catalyst S3.

[0033] Example 4

[0034] Add 50 g of NaY molecular sieve, 3 g of lanthanum chloride, 4 g of cerium nitrate and 200 g of water to a reaction kettle, stir evenly, heat up to 75 °C, then add 12 g of kaolin, 10 g of halloysite and 200 g of aluminum sol, mix and make a slurry, and spray dry to obtain catalyst microspheres; roast 100 g of the above catalyst microspheres at 380 °C, add 2000 g of water, 12 g of lanthanum chloride and 3.3 g of polyvinyl alcohol, heat up to 45 °C, stir for 70 minutes, filter to collect the filtrate, and dry the filter cake to obtain the finished catalyst S4.

[0035] Comparative Example 1

[0036] Add 30 g of NaY molecular sieve and 150 g of water to a reaction kettle, stir evenly, heat up to 60 °C, then add 76 g of kaolin and 50 g of aluminum sol, mix and make a slurry, and spray dry to obtain catalyst microspheres; roast 100 g of the above catalyst microspheres at 300 °C, add 500 g of water and 16.5 g of lanthanum chloride, heat up to 20 °C, stir for 2 hours, filter to collect the filtrate, and dry the filter cake to obtain the finished catalyst D1.

[0037] Comparative Example 2

[0038] Prepared according to the method of Patent CN201110144931.5

[0039] Mix 76 g of kaolin, 50 g of aluminum sol and 150 g of water to make a slurry, stir evenly, heat up to 60 °C and let stand for 1 hour, add 30 g of NaY molecular sieve and stir evenly, then spray dry to obtain catalyst microspheres; calcine 100 g of the above catalyst microspheres at 300 °C for 1 hour, add 500 g of water and 9 g of ammonium sulfate, then add them into a high-pressure reactor, react at 180 °C and 1.1 MPa for 1 hour, then filter, wash with water and dry to obtain primary ion-exchanged microspheres; calcine the above primary ion-exchanged microspheres at 500 °C for 2 hours, make a slurry with 1000 g of water, add 8 g of lanthanum chloride, react at 90 °C for 1 hour, then filter, wash with water and dry to obtain secondary ion-exchanged microspheres, and collect the filtrate L1; calcine the above secondary ion-exchanged microspheres at 500 °C for 0.5 hour, make a slurry with 100 g of water, add 8.5 g of lanthanum chloride, react at 90 °C for 1 hour, then filter, wash with water and dry, filter and collect the filtrate L2, and dry the filter cake to obtain the catalyst product D2

[0040] Detect the rare earth content of the collected filtrates and the sodium oxide and rare earth content of the catalyst products in Examples 1-4 and Comparative Examples 1-2, and the results are shown in Table 1

[0041] Table 1 Detection results of sodium oxide content, rare earth content of the catalyst and rare earth content of the filtrate

[0042]

[0043] From the detection results of Examples 1-4, it can be seen that the sodium oxide content of the catalyst prepared by the method of the present invention is less than 0.2%, and the rare earth content in the filtrate is less than 10 μg / g, with a high rare earth utilization rate. From the detection results of Example 1 and Comparative Example 1, it can be seen that by adjusting the prior exchange of some rare earth with NaY molecular sieve and adding polyvinyl alcohol during the microsphere ion exchange process, the rare earth utilization rate can be significantly improved, the loss of rare earth with the filtrate can be reduced, and the sodium oxide of the microsphere after ion exchange is lower. For the catalyst D1 prepared by Comparative Example 1, the rare earth content of the catalyst is significantly lower than the feeding amount, and a large amount of rare earth is not exchanged onto the catalyst during the exchange and is lost with the filtrate during the filtration process, resulting in a low rare earth utilization rate. If the rare earth entering the filtrate is not treated, it will also cause environmental pollution. Compared with the catalyst D2 prepared by the existing patent technology in Comparative Example 2, the sodium oxide content of the catalysts S1-S4 prepared by the method of the present invention is comparable to that of the catalyst D2, but during the preparation process of the molecular sieve, the rare earth content in the filtrate of Examples 1-4 is less than 10 ppm, and the rare earth is basically not lost, and the preparation process has a short flow. From the detection results of Example 1 and Comparative Example 2, it can be seen that under the condition of the same rare earth dosage, the catalyst prepared by the method provided by the present invention can take into account both the rare earth utilization rate and the sodium oxide content of the molecular sieve, has a simple process, and has good industrial application prospects. Moreover, the present invention does not require additional investment, does not produce ammonia nitrogen pollution and high-chlorine wastewater during the production process, realizes the goal of direct discharge of wastewater in the preparation process of fluid catalytic cracking catalysts, and ensures the continuous production of catalysts in existing devices.

[0044] Although the present invention has been described in detail by way of preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, those of ordinary skill in the art can make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions should all be within the scope of the present invention. / Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered by the protection scope of the present invention.

Claims

1. A preparation method of a fluid catalytic cracking catalyst, characterized in that, Specifically, it includes the following technological steps: (1) Mix the un-ion-exchanged NaY molecular sieve with a rare earth solution to make a slurry, obtaining a rare earth Y molecular sieve slurry; (2) Mix, make a slurry of the rare earth Y molecular sieve slurry, clay and binder, and form catalyst microspheres by spray drying; (3) Calcinate the catalyst microspheres at 300-500 °C, and conduct an ion exchange reaction of the calcined catalyst microspheres with water, rare earth salts and polyvinyl alcohol, filter and dry to obtain the catalyst; Based on dry basis, the calcined catalyst microspheres: rare earth salts calculated as RE2O3: polyvinyl alcohol: water = 1: (0.01-0.15): (0.001-0.05): (2-20).

2. The preparation method according to claim 1, characterized in that, In step (1), the rare earth solution is rare earth nitrate or rare earth chloride, and the rare earth includes at least one of lanthanum, cerium, praseodymium, neodymium, and yttrium.

3. The preparation method according to claim 2, characterized in that, In step (1), based on dry basis, NaY molecular sieve: rare earth calculated as RE2O3 = 1: 0.01-0.

15.

4. The preparation method according to claim 1, characterized in that, In step (1), the content of NaY molecular sieve in the rare earth Y molecular sieve slurry is 100-300 g / L.

5. The preparation method according to claim 1, characterized in that, In step (1), the temperature of the rare earth Y molecular sieve slurry is 10-100 °C.

6. The preparation method according to claim 1, characterized in that, In step (2), based on dry basis, the weight ratio of clay, binder and rare earth Y molecular sieve slurry is (10-85): (5-40): (10-70).

7. The preparation method according to claim 1, characterized in that, In step (2), the clay is selected from one or more of kaolin, montmorillonite, diatomite, halloysite, soapstone, rectorite, sepiolite, attapulgite, hydrotalcite, and bentonite.

8. The preparation method according to claim 1, characterized in that In step (2), the binder is one or more of a silicon-based binder, an aluminum-based binder or a silicon-aluminum binder; the silicon-based binder is silica sol; the aluminum-based binder is one or more of aluminum sol, pseudoboehmite, and aluminum gel; the silicon-aluminum binder is silica-alumina sol or silica-alumina gel.

9. The preparation method according to claim 1, wherein, In step (3), the temperature of the ion exchange reaction is 20-60 °C, the exchange time is 10-120 minutes, and the rare earth salts are rare earth chloride and / or rare earth nitrate.

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