A process for the preparation of a catalytic cracking catalyst

Abstract

The application provides a preparation method of a catalytic cracking catalyst, which comprises the following steps: forming a NaY molecular sieve filter cake layer, and then loading Y type molecular sieve exchanged by ammonia-nitrogen wastewater on the NaY filter cake, so as to recover the excess ammonium ions in the ammonia-nitrogen wastewater through the basic characteristics of the NaY filter cake layer and the ammonium ion adsorption characteristics of the NaY molecular sieve; meanwhile, the excess ammonium ions can also exchange part of Na of the NaY molecular sieve in the recycling process of the excess ammonium ions in the NaY molecular sieve layer + , effectively removing Na + of the NaY molecular sieve layer, and recycling the ammonium ions lost in the ammonia-nitrogen wastewater through the adsorption and ion exchange of the NaY molecular sieve. The humic acid added in the NaY molecular sieve slurry is a multi-element organic complex, which is dissolved in the NaY molecular sieve system to form sodium humate, and the sodium humate can limit the migration of the ammonium ions in the filtrate through adsorption and exchange, so as to inhibit the loss of the ammonium ions with the filtrate.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of catalyst preparation, in particular to a preparation method of a catalytic cracking catalyst. BACKGROUND

[0002] It is well known that the petroleum refining industry is an important pillar of the national economy, with long industrial chain, wide product coverage and close relationship with people's life. The most important refining method in the petroleum refining process is catalytic cracking technology, 70% of the daily required gasoline, 40% of the daily required diesel and 35% of the daily required propylene in China come from catalytic cracking, and the catalytic cracking catalyst is the core content of catalytic cracking.

[0003] In order to reduce the content of sodium oxide which has important influence on catalytic activity, selectivity and stability in the catalyst, ammonium salt is generally used in the production process of the catalytic cracking catalyst to exchange Na+ in the zeolite molecular sieve of the catalyst and its active component. + Ion exchange is carried out, for example, the preparation method of the molecular sieve using ammonium salt for exchange is disclosed in Chinese patent CN1210034A and US4357265. In order to improve the exchange degree of sodium ions, multiple ammonium exchange and multiple washing methods are often used. The waste liquid after the exchange of the molecular sieve and the washing of the catalyst is high ammonia-nitrogen wastewater, which increases the investment and maintenance operation cost of the ammonia-nitrogen removal equipment of the enterprise, increases the production cost and the burden of wastewater treatment, and in addition, the ammonia-nitrogen exchanged or adsorbed on the molecular sieve or the catalyst will enter the atmosphere in the intermediate calcination process, which will also cause air pollution. Therefore, reducing the production cost and solving the ammonia-nitrogen pollution in the preparation process of the catalyst are also the key and difficulty of the development of the catalytic cracking catalyst.

[0004] CN103240113A discloses a preparation method of an in-situ crystallization catalyst for reducing ammonia-nitrogen pollution, which comprises adding polydimethyl diallyl ammonium chloride which can adjust the stacking mode of kaolin during spraying, cleaning the exchange ion exchange environment with an acidic solution after obtaining the in-situ crystallization product, and then exchanging and calcining through other steps to obtain the catalytic cracking catalyst. The method can reduce the use amount of ammonium salt by more than 15%, effectively alleviate the ammonia-nitrogen pollution problem in the preparation process of the in-situ crystallization catalyst, reduce the production cost, and improve the reaction performance of the catalyst.

[0005] CN100404432C discloses a method for reducing ammonia-nitrogen pollution in the modification process of zeolite, which comprises exchanging sodium in the zeolite with a potassium compound and then further modifying the zeolite with ammonium salt. The method does not increase the modification cost of the zeolite, reduces the use amount of ammonium salt by about 50%, thereby reducing the ammonia-nitrogen pollution and the burden and investment in the wastewater treatment process, and is an environmental protection technology for modifying zeolite; the prepared zeolite and catalyst have lower sodium oxide content, and the performance of the catalyst is basically unchanged or improved.

[0006] CN103028431A discloses a clean production process of a molecular sieve catalytic cracking catalyst, which uses a conventional in-situ crystallization method to prepare a modified molecular sieve or a molecular sieve catalytic cracking catalyst, and mixes a molecular sieve crystallization filtration mother liquor and / or a crystallization material water washing water with ammonia-nitrogen wastewater generated in a molecular sieve exchange process as a spray washing liquid of a spray washing tower for catalyst spray granulation tail gas, and adds an aluminum salt or an acid liquid to the spray recovery liquid, forms a gel, filters, discharges the filtrate, and uses the filter residue as a raw material for synthesizing a molecular sieve. The method can directly discharge high ammonia-nitrogen content wastewater generated in the process at a very low operation cost while preparing qualified catalytic cracking catalyst products, and can fully recycle and use silicon compounds in the wastewater.

[0007] Although the above methods greatly reduce ammonia-nitrogen wastewater in the catalytic cracking preparation process, ammonium ions are still introduced, and the production cannot be achieved without ammonia. The ammonia-nitrogen content of the filtrate in the ammonium exchange step is as high as 4000-10000 mg / kg, and the ammonia-nitrogen content of the washing water is as high as 150-1500 mg / kg, while the first-level ammonia-nitrogen discharge standard in the national standard "Integrated Wastewater Discharge Standard" is 15 mg / kg, and the second-level discharge standard is 50 mg / kg. Therefore, with the implementation of the new Environmental Protection Law and the improvement of the public environmental protection awareness, people urgently need to develop a new catalytic cracking catalyst preparation technology with simple process, low cost, and no ammonia in the production process.

[0008] Patent CN102795636B discloses an exchange modification method for reducing the content of sodium oxide in Y-type molecular sieves, which is characterized in that a Y-type molecular sieve with a high Na content is contacted with a water solution containing inorganic acid and organic acid at 0-5°C for 0.5-3 hours, and then separated, washed, and dried to obtain a Y-type molecular sieve with a lower content of sodium oxide; wherein the weight ratio of H2O to molecular sieve is 11-18:1. In the process of significantly reducing the content of sodium oxide in the Y-type molecular sieve, no ammonium salt is used at all, the ammonia-nitrogen pollution problem is eliminated from the source, and the water consumption and wastewater discharge in the exchange process of the Y-type molecular sieve are also significantly reduced.

[0009] Patent CN102557070B discloses a method for exchange and sodium removal using organic carboxylic acid in the preparation process of Y-type molecular sieves, which mixes NaY molecular sieves, organic carboxylic acid, and a dispersion medium, stirs, filters, washes, and dries to obtain NaHY molecular sieves; wherein the organic carboxylic acid is acetic acid; the raw material ratio is acetic acid / NaY molecular sieve = 0.15-0.6 mmol / g, and the dispersion medium / NaY molecular sieve = 5-200 (w / w). The method avoids the introduction of byproduct inorganic ammonium salt, reduces unnecessary inorganic salt byproducts generated in the exchange process, and reduces the impact of nitrogen-containing wastewater discharge on the environment.

[0010] Patent CN102794191B discloses a new method for preparing catalytic cracking catalyst by ammonia-free method, the molecular sieve and catalyst exchange process in the method is carried out in a mixed acid solution of inorganic acid and organic acid at low temperature and low acid concentration. The above method reduces the content of sodium oxide in the catalyst, avoids ammonia nitrogen pollution in the molecular sieve exchange and catalyst washing process, greatly reduces water consumption and wastewater treatment cost. The use of inorganic acid and organic acid for molecular sieve and catalyst exchange washing and sodium reduction easily destroys the crystal structure of molecular sieve, resulting in poor crystallinity of molecular sieve in the catalyst, reducing the thermal stability and hydrothermal stability of the catalyst; and the method needs to be exchanged at a temperature of 0-5℃, the operating conditions are harsh, and the industrial operation is difficult.

[0011] Patent CN102553630A adopts a traditional in-situ crystallization method to prepare NaY molecular sieve microspheres, then contacts with silicon tetrachloride gas according to a weight ratio of 0.1-0.9:1, reacts at 150-500℃ for 10 minutes to 6 hours, and washes the in-situ crystallized NaY zeolite microspheres after reaction with deionized water at 20-100℃ to remove the residual Na + 、Cl - 、Al 3+ soluble by-products, and then prepares a catalytic cracking catalyst containing high-silicon-aluminum ratio small-grained Y-type molecular sieve, but the method still cannot avoid the disadvantages of large difficulty, high production cost, and difficult sodium reduction of molecular sieve or catalyst of in-situ crystallization technology.

[0012] Patent CN106732745B discloses a preparation method of a catalytic cracking catalyst, characterized in that the method contacts NaY molecular sieve raw powder with halogen-containing gas to perform a gas phase ion exchange reaction, one-step completes the sodium reduction and stabilization of NaY molecular sieve raw powder, and prepares a low-sodium high-silicon-aluminum ratio molecular sieve. The method also prepares an acid-activated composite clay by compounding different types of clay raw ores and treating with high-concentration acid, mixes the low-sodium high-silicon-aluminum ratio molecular sieve, the acid-activated composite clay, a binder, rare earth, and deionized water, sprays and granulates after beating, and obtains the catalytic cracking catalyst product after calcination and solidification without washing and drying.

[0013] The halogen-containing gas (such as silicon tetrachloride) contacts with Y-type molecular sieve or catalyst at high temperature, aluminum is removed at the same time, silicon fills into the aluminum vacancies, the removed aluminum escapes in the form of aluminum chloride gas, and the sodium ion is removed by water washing or acid extraction, which completely eliminates ammonia nitrogen pollution. However, silicon tetrachloride is hydrolyzed to generate silica gel and hydrochloric acid when it contacts with water, the silica gel is easy to block the pipeline, and the hydrochloric acid greatly damages the equipment and molecular sieve. At the same time, chlorine has strong corrosion and cannot be discharged into the atmosphere, but can only be absorbed by water and discharged into wastewater, which will cause the salt content in wastewater to increase day by day and the waste of chlorine element.

[0014] Patent CN1840614A contacts one or more of dry NaY, RE NaY, REHY or REY molecular sieve with silicon tetrachloride according to the weight ratio of silicon tetrachloride:Y type molecular sieve = 0.1-0.9:1, at 100-600℃, for 10 minutes to 6 hours, and the sodium oxide of the Y type molecular sieve after gas phase ion exchange reaction is removed by more than 90% by weight. Then the reacted Y type molecular sieve is directly mixed with a binder and clay, and is formed by spraying, and then is washed, filtered and dried to obtain a catalytic cracking catalyst product. The disadvantages of this method are that the rare earth ions are greatly exchanged by silicon tetrachloride during the gas phase ion exchange of the rare earth-containing Y type molecular sieve, which reduces the utilization rate of rare earth; and the Y type molecular sieve is not washed and exchanged after sodium reduction and stabilization, and is directly mixed with other raw materials for spraying, which causes harmful ions such as Na + , NH4 + , SO4 2- ions removed during the gas phase ion exchange to re-enter the molecular sieve and the catalyst.

[0015] As can be seen from the above, the use of acid exchange and gas phase ion exchange can reduce the ammonia-nitrogen wastewater discharge during catalyst production, but the acid exchange conditions are harsh, and the gas phase ion exchange requires additional equipment investment. The above technical solutions cannot meet the direct discharge requirement of ammonia-nitrogen wastewater from the existing catalyst production device.

[0016] Therefore, how to effectively improve the utilization rate of ammonium ions in the existing catalyst production process and reduce ammonia-nitrogen wastewater discharge is an important measure for catalyst production enterprises to reduce costs and increase efficiency, and is also one of the key research topics of catalyst production enterprises. SUMMARY

[0017] The purpose of the present application is to provide a preparation method of a catalytic cracking catalyst, which solves the problem of serious ammonia-nitrogen pollution during the production of a catalytic cracking catalyst, and realizes direct discharge of catalyst wastewater from the existing catalyst production device without additional investment, thereby ensuring green production of the catalyst.

[0018] To achieve the above purpose, the present application provides a preparation method of a catalytic cracking catalyst, comprising the following steps:

[0019] 1) mixing NaY molecular sieve, humic acid and water to form a NaY molecular sieve filter cake layer, wherein the weight ratio of the humic acid to the dry NaY molecular sieve is 0.001-0.05;

[0020] 2) Y-type molecular sieve is beaten with ammonia-nitrogen wastewater to obtain Y-type molecular sieve slurry, the Y-type molecular sieve slurry is filtered through a NaY molecular sieve filter cake layer to obtain a composite filter cake layer, then ion exchange is carried out through a first ammonium salt exchange solution and / or a rare earth exchange solution, and after water washing, a composite molecular sieve filter cake is obtained; the Y-type molecular sieve is Y-type molecular sieve of one exchange and one calcination and / or Y-type molecular sieve of two exchanges and one calcination, the weight ratio of ammonium salt in the first ammonium salt exchange solution to the total amount of NaY molecular sieve dry basis and Y-type molecular sieve dry basis is 0-0.2, and the weight ratio of rare earth in the rare earth exchange solution, calculated as oxidized rare earth, to the total amount of NaY molecular sieve dry basis and Y-type molecular sieve dry basis is 0-0.10;

[0021] 3) the composite molecular sieve filter cake, inorganic oxide, clay, binder and water are mixed and beaten to form a slurry, spray-dried to form a shape, calcined and solidified to obtain catalyst microspheres, the catalyst microspheres and water are mixed and beaten to form a slurry, filtered, ion exchanged with a second ammonium salt exchange solution, water washed, and dried to obtain a catalytic cracking catalyst; wherein the weight ratio of ammonium salt in the second ammonium salt exchange solution to the dry basis of the catalyst microspheres is 0.005-0.10.

[0022] The preparation method of the catalytic cracking catalyst provided by the application, and the sodium oxide content of the NaY molecular sieve is 9-15%.

[0023] The NaY molecular sieve in the application can be prepared by the existing method, or can be obtained by commercial purchase, and the preparation method thereof is known to those skilled in the art. For example, the synthesis method of the NaY molecular sieve provided in patent CN103449468B: mixing water glass, sodium metaaluminate and deionized water, aging at 15-70℃ for 0.5-48 hours to obtain a crystallization directing agent; uniformly mixing the crystallization directing agent, water glass, acidic aluminum salt and sodium aluminate solution to prepare a silica-alumina gel; crystallizing the silica-alumina gel at 80-140℃; crystallizing for 0.1-80 hours; adding a peroxide to the crystallized silica-alumina gel, so that the molar ratio of O2 in the peroxide to Al2O3 in the gel is 0.05-20, and continuing to crystallize for 5-20 hours. 2-

[0024] The beating conditions of the NaY molecular sieve with water are known to those skilled in the art, and the content of the NaY molecular sieve in the slurry is generally 100-300 g / L. The temperature of the slurry can be 10-100℃, preferably 50-90℃.

[0025] The preparation method of the catalytic cracking catalyst provided by the application, and the humic acid is one or more of yellow humic acid, brown humic acid and black humic acid.

[0026] The preparation method of the catalytic cracking catalyst provided by the application, and the ammonium salt is one or more of ammonium chloride, ammonium sulfate, ammonium oxalate, ammonium phosphate and ammonium bicarbonate, preferably ammonium chloride and / or ammonium sulfate.

[0027] ​The preparation method of the catalytic cracking catalyst, the rare earth is one or more of lanthanum, cerium, praseodymium, neodymium and yttrium.

[0028] The preparation method of the catalytic cracking catalyst, the one-interaction-one-calcination Y type molecular sieve is one or more of one-interaction-one-calcination ultrastable Y molecular sieve, one-interaction-one-calcination rare earth Y molecular sieve, one-interaction-one-calcination rare earth hydrogen Y molecular sieve and one-interaction-one-calcination hydrogen Y molecular sieve; the two-interaction-one-calcination Y type molecular sieve is one or more of two-interaction-one-calcination ultrastable Y molecular sieve, two-interaction-one-calcination rare earth Y molecular sieve, two-interaction-one-calcination rare earth hydrogen Y molecular sieve and two-interaction-one-calcination hydrogen Y molecular sieve.

[0029] The preparation method of the catalytic cracking catalyst, the inorganic oxide is one or more of rare earth oxide, magnesium oxide and silicon oxide; the clay is one or more of kaolin, halloysite and montmorillonite; the binder is one or more of aluminum sol, silicon sol and pseudo-boehmite.

[0030] The preparation method of the catalytic cracking catalyst, the ammonia-nitrogen wastewater in step 2) is the filtrate collected in the ion exchange process in step 2) and / or the filtrate collected in the ion exchange process in step 3), or can be the ammonium-containing filtrate collected outside the process, and is preferably the filtrate collected in the ion exchange process in step 3).

[0031] The preparation method of the catalytic cracking catalyst, the mass ratio of the ammonia-nitrogen wastewater to the Y type molecular sieve in step 2) is 2-10, and is preferably 3-6.

[0032] The spray drying and calcination solidification conditions in the application are well known to those skilled in the art, for example, the drying temperature is room temperature to 200 DEG C, preferably 100-150 DEG C, the calcination solidification temperature is 300-600 DEG C, preferably 400-500 DEG C, and the calcination time is 10-200 minutes, preferably 30-60 minutes.

[0033] The preparation method of the catalytic cracking catalyst, steps 1) and 2) are carried out on a first horizontal belt filter, and the first horizontal belt filter comprises a NaY molecular sieve filter cake layer forming area, a composite filter cake layer forming area, an ion exchange area and a water washing area connected in series; and step 3) is carried out on a second horizontal belt filter, and the second horizontal belt filter comprises a filter cake forming area, an ion exchange area and a water washing area connected in series.

[0034] The application has the following beneficial effects:

[0035] The application provides a preparation method of a catalytic cracking catalyst, and first forms a NaY molecular sieve filter cake layer, then loads Y type molecular sieves exchanged by ammonia-nitrogen wastewater on the NaY filter cake, recovers excess ammonium ions in the ammonia-nitrogen wastewater through the basic characteristics of the NaY filter cake layer and the ammonium ion adsorption characteristics of the NaY molecular sieve, and at the same time, the excess ammonium ions can also exchange part of Na of the NaY molecular sieve in the recycling process of the excess ammonium ions in the NaY molecular sieve layer + , effectively removes Na of the NaY molecular sieve layer + , and realizes recycling of the ammonium ions through the adsorption and ion exchange of the NaY molecular sieve and the recovery of the lost ammonium ions in the ammonia-nitrogen wastewater. The humic acid added in the NaY molecular sieve slurry is a multi-element organic complex, forms sodium humate in the NaY molecular sieve system, and the sodium humate can limit the migration of the ammonium ions in the filtrate through adsorption and exchange, and inhibit the loss of the ammonium ions with the filtrate. The preparation method of the catalytic cracking catalyst provided by the application recycles the ammonia-nitrogen wastewater of the catalyst microspheres for the molecular sieve ion exchange process, can effectively reduce the water consumption and ammonium salt consumption in the catalyst production process, and is beneficial to reducing the production cost of the catalyst. Therefore, compared with the prior art, the preparation method of the catalytic cracking catalyst provided by the application does not need to increase additional investment, can realize the direct discharge of the wastewater on the existing production device, and has a simple operation process, thereby providing technical support for green production and energy saving and consumption reduction of the catalyst enterprise. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 It is a flow chart of the molecular sieve ion exchange process of the application;

[0037] Figure 2 It is a flow chart of the catalyst microsphere ion exchange process of the application.

[0038] In the drawings, the reference signs are as follows:

[0039] 1, 5, 15, 16, a beater;

[0040] 2, 6, 10, 13, 17, 21, 25, a pipeline;

[0041] 3, 18, a filter cloth;

[0042] 4, a NaY filter cake formation area

[0043] 7, a Y type molecular sieve filter cake formation area

[0044] 8, 23, a liquid receiver

[0045] 9, 12, 20, 24, a container

[0046] 14, 26, a water washing area

[0047] 19, a microsphere filter cake formation area

[0048] 11,22 ion exchange zone

[0049] 27 recovered filtrate DETAILED DESCRIPTION

[0050] The application will be described in detail below by way of examples. It is necessary to point out here that the following examples are only used to further illustrate the application and cannot be understood as limiting the scope of protection of the application. Those skilled in the art can make some non-essential improvements and adjustments to the application according to the above description of the application.

[0051] According to the method provided by the application, the application can be implemented according to the flow shown in Figure 1 、 Figure 2

[0052] I. Formation of NaY filter cake

[0053] NaY molecular sieve at 10-100°C, preferably 50-90°C, humic acid and water are slurried to form a slurry, which is continuously loaded from the slurry tank 1 through the pipeline 2 to the filter cloth 3 of the horizontal vacuum belt filter, the filter cloth continuously moves into the NaY filter cake formation area 4. The liquid receiver 8 is located below the filter cloth 3, the liquid receiver 8 is vacuumed, under the action of vacuum, the liquid in the slurry on the filter cloth 3 enters the liquid receiver 8 through the filter cloth 3. At the same time, the NaY slurry on the filter cloth 3 forms a filter cake, the loading speed of the NaY slurry should ensure that the thickness of the NaY filter cake is 0.5-1.5 cm, preferably 0.8-1.5 cm. The vacuum degree in the vacuum box 8 makes the surface of the filter cake not crack. The vacuum degree in the vacuum box 8 is generally 0.02-0.08 MPa, preferably 0.05-0.08 MPa.

[0054] II. Formation of Y-type molecular sieve filter cake

[0055] Y-type molecular sieve is slurried with ammonia-nitrogen wastewater, Y-type molecular sieve slurry at 50-100°C is continuously loaded from the slurry tank 5 through the pipeline 6 to the NaY filter cake layer of the horizontal vacuum belt filter, and moves into the Y-type molecular sieve filter cake formation area 7 with the filter cloth. The ammonia-nitrogen wastewater can be provided by the liquid receiver 23 of the microsphere exchange process described below, which can reduce the amount of water used and also recover ammonium in the filtrate of the catalyst microsphere ion exchange process, thereby reducing the amount of sewage discharged. At the same time, the Y-type molecular sieve slurry on the filter cloth 3 forms a filter cake, and the loading speed of the Y-type molecular sieve slurry should ensure that the thickness of the Y-type molecular sieve filter cake is 0.5-1.5 cm, preferably 0.8-1.5 cm.

[0056] III. Ion exchange of molecular sieve

[0057] ​As the filter cloth 3 moves, the filter cake formed in the NaY filter cake formation zone 4 and the Y zeolite filter cake formation zone 7 enters the ion exchange zone 11. An ammonium salt exchange solution and / or a rare earth exchange solution at a temperature of 20-100°C, preferably 30-90°C, is added from the vessel 9 through the line 10. Under the action of the vacuum, the ammonium salt exchange solution and / or the rare earth exchange solution passes through the filter cake while ion exchange is taking place.

[0058] IV. Water washing of the zeolite

[0059] The washing method is known to those skilled in the art. The filter cake obtained in the ion exchange zone 11 enters the water washing zone 14. Deionized water is added from the vessel 12 through the line 13. The weight ratio of the deionized water to the zeolite is generally 1-15, preferably 2-10. The temperature of the deionized water is 20-100°C, preferably 30-90°C. Under the action of the vacuum, the liquid passes through the filter cake, washing away the residual ions, especially anions, in the filter cake.

[0060] V. Formation and solidification of the catalyst microspheres

[0061] The washed composite zeolite filter cake enters the pulping tank 15, where it is pulped with inorganic oxides, clay, a binder and water, and is spray formed and solidified by calcination to obtain solidified catalyst microspheres.

[0062] VI. Formation of the microsphere filter cake

[0063] The solidified catalyst microspheres enter the pulping tank 16, where they are pulped with water. The microsphere slurry is continuously loaded from the pulping tank 16 through the line 17 onto the filter cloth 18 of a horizontal vacuum belt filter. The filter cloth is continuously moved and enters the microsphere filter cake formation zone 19. A liquid receiver 23 is located below the filter cloth 18. The liquid receiver 23 is evacuated, and under the action of the vacuum, the liquid in the slurry on the filter cloth 18 passes through the filter cloth 18 into the liquid receiver 23. At the same time, the microsphere slurry on the filter cloth 18 forms a filter cake. The loading speed of the microsphere slurry should be such that the thickness of the microsphere filter cake is 0.5-2.0 cm, preferably 0.8-1.5 cm. The vacuum in the vacuum box 23 is generally 0.02-0.08 MPa, preferably 0.03-0.08 MPa.

[0064] VII. Ammonium exchange of the catalyst microspheres

[0065] As the filter cloth 18 moves, the filter cake formed in the microsphere filter cake formation zone 19 enters the ion exchange zone 22. An ammonium salt solution at a temperature of 20-100°C, preferably 30-90°C, is added from the vessel 20 through the line 21. Under the action of the vacuum, the ammonium salt solution passes through the filter cake while ion exchange is taking place.

[0066] VIII. Washing of the catalyst microspheres

[0067] The washing method is well known to those skilled in the art. The microspheres obtained in the ion exchange zone 22 are washed by adding deionized water from the container 24 through the line 25, and the washing is carried out in the water washing zone 26. The weight ratio of deionized water to microspheres is generally 1-15, preferably 2-10, and the temperature of the deionized water is 20-100°C, preferably 30-90°C. Under the action of vacuum, the liquid permeates through the filter cake, and the residual ions in the filter cake are washed away to obtain the recovered filtrate 27.

[0068] The following examples are carried out using a cloth funnel filter device to illustrate the method provided by the present application. Since the cloth funnel filter device also undergoes the stages of filter cake formation, ion exchange and washing, only these steps are carried out separately, and thus are equivalent to the continuous process carried out on the belt filter.

[0069] Source of raw materials:

[0070] 1) NaY molecular sieve: commercial product produced by Lanzhou Petrochemical Company, crystallinity 94%, Si / Al ratio 5, Na2O content 14.3%; one exchange one calcination ultrastable Y molecular sieve: produced by Lanzhou Petrochemical Company, Na2O content 4.1%, cell constant 24.55 angstroms;

[0071] two exchange one calcination ultrastable Y molecular sieve: produced by Lanzhou Petrochemical Company, Na2O content 1.5%, cell constant 24.54 angstroms;

[0072] one exchange one calcination hydrogen Y molecular sieve: produced by Lanzhou Petrochemical Company, Na2O content 4.6%, cell constant 24.65 angstroms;

[0073] two exchange one calcination hydrogen Y molecular sieve: produced by Lanzhou Petrochemical Company, Na2O content 1.3%, cell constant 24.65 angstroms;

[0074] two exchange one calcination rare earth Y molecular sieve: produced by Lanzhou Petrochemical Company, Na2O content 1.1%, RE2O3 content 14.8%, cell constant 24.66 angstroms;

[0075] Kaolin, halloysite, montmorillonite, silica sol, pseudo-boehmite and alumina sol are all from Lanzhou Petrochemical Company.

[0076] 2) Fulvic acid, brown humic acid, black humic acid, ammonium chloride, ammonium sulfate, ammonium oxalate, ammonium phosphate, ammonium bicarbonate, lanthanum chloride, cerium nitrate, yttrium oxide, magnesium oxide, white carbon black: analytical pure, all are chemical reagents.

[0077] Specific analysis method:

[0078] 1) Sodium oxide content of molecular sieve: analyzed by X-ray fluorescence spectrometry.

[0079] 2) Ammonia nitrogen content of filtrate: detected by Nessler's reagent spectrophotometry.

[0080] Comparative Example 1

[0081] The sample was prepared according to patent CN103028431A.

[0082] The NaY type molecular sieve was filtered and washed with water by a belt filter, the crystallization mother liquor and the washing water of the crystallization material were collected, the filter cake was exchanged twice with ammonium (the ammonium chloride to NaY molecular sieve dry basis ratio was 0.05:1) and desodium by intermediate calcination to obtain a modified Y molecular sieve with a sodium oxide content of 1.2%; a catalyst cracking catalyst microsphere was prepared by mixing the modified Y molecular sieve, kaolin, aluminum sol (calculated as aluminum oxide) and yttrium oxide in a ratio of 35:54:10:1 into a gel with a solid content of 38% and then spray granulating in a spray granulation tower, and then the microsphere was exchanged with ammonium on a belt filter, the amount of ammonium chloride was such that the weight ratio of ammonium chloride to the microsphere was 0.08, and the sodium oxide content of the filter cake was 0.2%, and the filter cake was dried by flash drying to obtain a catalyst cracking catalyst product. The exchange filter solution mixture A was collected, and the ammonia nitrogen content was 5962 μg / g. The crystallization material water and part of the crystallization mother liquor were added to the exchange filter solution mixture to make the pH value of the mixture 12.5, and then the mixture was used as a spray washing liquid for a spray washing tower of the tail gas of a spray granulation tower, the temperature of the spray recovery liquid was 92℃, and the ammonia nitrogen content was 185 μg / g; then sulfuric acid aluminum sulfate solution was added to the spray washing recovery liquid to make the pH value 9.5, and aged for 1 hour, and then filtered to obtain a silicon-aluminum gel, and the ammonia nitrogen content of the filter solution was 21 μg / g.

[0083] Comparative Example 2

[0084] The sample was prepared according to patent CN102794191B.

[0085] The preparation of the catalytic cracking catalyst included the following steps:

[0086] (1) Exchange washing of Na-containing Y type molecular sieve: 2.7 kg of acetic acid was weighed, stirred with a proper amount of cold water to dissolve, then 8.1 kg of 36% hydrochloric acid was added, and then cold water was continuously added to dilute the solution to 1000 L to prepare a H + mixed acid solution with a molar concentration of 0.17 mol / L, the solution temperature was controlled at 3.5±0.5℃, Y type molecular sieve raw powder dry basis 71.4 kg (water:molecular sieve raw powder dry basis weight ratio = 14:1) was added under stirring, then stirred at 3.5±0.5℃ for 2 hours, then the slurry was filtered, and the filter cake was washed with 5 times the weight of deionized water based on the Y type molecular sieve raw powder dry basis;

[0087] (2) The product of step (1) was flash dried and calcined at 550℃ for 3 hours;

[0088] (3) The product of step (2) is slurried to prepare a molecular sieve slurry according to a ratio of molecular sieve: water = 1:3;

[0089] (4) The molecular sieve slurry obtained in step (3) is mixed with kaolin, aluminum sol (calculated as alumina), and yttrium oxide according to a ratio of molecular sieve: kaolin: aluminum sol (calculated as alumina): yttrium oxide = 35:54:10:1 to prepare a catalyst mixed slurry;

[0090] (5) The slurry obtained in step (4) is spray-dried to prepare catalyst microspheres according to a conventional spray-drying forming method for preparing catalytic cracking catalysts;

[0091] (6) Catalyst washing: 540 g of acetic acid is stirred to dissolve in a proper amount of cold water, and then 1620 g of hydrochloric acid with a concentration of 36% is added. The solution is diluted to 1000 L with cold water to prepare a mixed acid solution with a H+ molar concentration of 0.034 mol / L. The temperature of the solution is controlled at 3.5±0.5 ℃. The catalyst microspheres prepared in step (5) with a dry basis of 143 kg are added to the solution under stirring. Then the mixture is stirred at 3±0.5 ℃ for 20 minutes, and then filtered. The filter cake is rinsed with 5 times the weight of the catalyst with deionized water;

[0092] (7) The product of step (6) is air-dried to obtain the finished product D2 of the catalytic cracking catalyst. The sodium oxide content of the D2 sample is 0.1%.

[0093] Comparative Example 3

[0094] 1) The two-exchange-one-calcination ultrastable Y molecular sieve is mixed with the ammonia-nitrogen wastewater (the exchange filtrate mixture A of Comparative Example 1) to prepare a two-exchange-one-calcination ultrastable Y molecular sieve slurry. The mass of the exchange filtrate mixture A is 5 times the mass of the NaY molecular sieve. The obtained two-exchange-one-calcination ultrastable Y molecular sieve slurry is heated to 70 ℃ and stirred for 1 h. The slurry is poured into a Buchner funnel, and the filter bottle is vacuumed to 0.07 MPa. A one-exchange-one-calcination Y molecular sieve filter cake with a thickness of 10 mm is formed on the filter cloth.

[0095] 3) When there is no liquid on the surface of the filter cake, an ammonium chloride solution with a temperature of 90 ℃ is immediately added at a speed that ensures that no cracks are formed on the surface of the filter cake. The amount of the ammonium chloride is such that the weight ratio of the ammonium chloride to the one-exchange-one-calcination Y molecular sieve is 0.10. Deionized water with a temperature of 80 ℃ is immediately added to wash the filter cake when there is no liquid on the surface of the filter cake. The weight ratio of the deionized water to the one-exchange-one-calcination Y molecular sieve is 5. Then the molecular sieve filter cake is taken out and the filtrate B is collected.

[0096] 4) The molecular sieve slurry obtained in step (3) is mixed with kaolin, aluminum sol (calculated as alumina), and yttrium oxide according to a ratio of molecular sieve: kaolin: aluminum sol (calculated as alumina): yttrium oxide = 35:54:10:1 to prepare a catalyst mixed slurry;

[0097] 5) The slurry obtained in step (4) is spray dried to prepare catalyst microspheres according to the conventional spray drying method for preparing catalytic cracking catalysts, and the catalyst microspheres are calcined to solidify.

[0098] 6) Catalyst washing: The solidified catalyst microspheres obtained in step 5) are mixed with water to prepare a slurry having a catalyst microsphere content of 110 g / L, and the obtained slurry is heated to 60°C and poured into a Buchner funnel, while the filter bottle is vacuumed to 0.06 MPa, to form a filter cake having a thickness of 10 mm on the filter cloth.

[0099] 7) When the filter cake surface is free of liquid in step 6) above, a solution containing ammonium chloride having a temperature of 90°C is immediately added, and the amount of ammonium chloride is such that the weight ratio of ammonium chloride to microspheres is 0.08. When the filter cake surface is free of liquid, deionized water having a temperature of 90°C is immediately added to wash the filter cake, and the weight ratio of deionized water to microspheres is 5. Then the filter cake is removed and the filtrate C is collected, and the catalyst sample D3 is obtained by drying, which has a sodium oxide content of 0.1%, and the ammonia nitrogen content of the filtrate B is 1328 ppm.

[0100] Example 1

[0101] 1) NaY molecular sieves are mixed with fulvic acid and water to prepare a molecular sieve slurry having a molecular sieve content of 180 g / L, wherein the amount of fulvic acid added is such that the weight ratio of fulvic acid to dry NaY molecular sieves is 0.03:1, and the obtained molecular sieve slurry is heated to 80°C and poured into a Buchner funnel, while the filter bottle is vacuumed to 0.07 MPa, to form a filter cake having a thickness of 10 mm on the filter cloth.

[0102] 2) The two-exchange-one-calcination Y molecular sieves are mixed with ammonia-nitrogen-containing wastewater (the exchange filtrate mixture A of Comparative Example 1) to prepare a two-exchange-one-calcination Y molecular sieve slurry, and the mass of the exchange filtrate mixture A is 5 times that of the molecular sieves, and the obtained two-exchange-one-calcination Y molecular sieve slurry is heated to 70°C and stirred for 1 h, and then poured onto the NaY filter cake of step 1) in a Buchner funnel, while the filter bottle is vacuumed to 0.07 MPa, to form a two-exchange-one-calcination Y molecular sieve filter cake having a thickness of 10 mm on the filter cloth.

[0103] 3) When the filter cake surface is free of liquid in the above step, a solution containing ammonium chloride having a temperature of 90°C is immediately added, and the addition speed is such that no cracks are formed on the filter cake surface, and the amount of ammonium chloride is such that the weight ratio of ammonium chloride to composite molecular sieves is 0.10. When the filter cake surface is free of liquid, deionized water having a temperature of 80°C is immediately added to wash the filter cake, and the weight ratio of deionized water to molecular sieves is 5. Then the molecular sieve filter cake is removed and the filtrate D is collected.

[0104] 4) The slurry of step (3) is mixed with kaolin, alumina sol and yttria in the ratio of 35:54:10:1 (molecular sieve: kaolin: alumina sol: yttria) to form a catalyst mixed slurry;

[0105] 5) The slurry of step (4) is spray dried to form catalyst microspheres by a conventional spray drying method for preparing a catalytic cracking catalyst, and the catalyst microspheres are calcined and solidified.

[0106] 6) The solidified catalyst microspheres of step 5) are mixed with water to form a slurry having a catalyst microsphere content of 110 g / L, and the resulting slurry is heated to 60°C and poured into a Buchner funnel while the filter bottle is vacuumed to 0.06 MPa to form a filter cake having a thickness of 10 mm on the filter cloth.

[0107] 7) When the filter cake surface of step 6) above is free of liquid, a solution containing ammonium chloride having a temperature of 90°C is immediately added in an amount such that the weight ratio of ammonium chloride to microspheres is 0.08. When the filter cake surface is free of liquid, deionized water having a temperature of 90°C is immediately added in an amount such that the weight ratio of deionized water to microspheres is 5. The filter cake is then removed and the filtrate E is collected, and the filter cake is dried to obtain a catalyst sample S1 having a sodium oxide content of 0.09%, and the filtrate D has an ammonia nitrogen content of 8 ppm.

[0108] Example 2

[0109] The operating steps are the same as in Example 1, except that:

[0110] Step 1) The slurry of NaY molecular sieve has a content of 300 g / L, the brown acid is added in an amount such that the weight ratio of brown acid to dry NaY molecular sieve is 0.001:1, the slurry temperature is 15°C, the vacuum degree of the filter bottle is 0.08 MPa, and the filter cake thickness is 5 mm.

[0111] Step 2) The slurry of the mixed molecular sieve is mixed with the ammonia nitrogen waste water (filtrate E) in an amount of 2 times the molecular sieve, the slurry temperature is 50°C, the stirring time is 2 h, the vacuum degree of the filter bottle is 0.08 MPa, and the filter cake thickness is 15 mm.

[0112] Step 3) The weight ratio of lanthanum chloride (calculated as rare earth oxide) to the composite molecular sieve is 0.10. The deionized water temperature is 100°C, and the weight ratio of deionized water to molecular sieve is 1. The molecular sieve filter cake is removed and the filtrate F is collected.

[0113] Step 4) The ratio of molecular sieve: halloysite: silica sol (calculated as silicon dioxide): magnesium oxide is 35:54:10:1.

[0114] Step 5) Spray drying and solidification.

[0115] Step 6) Catalyst microspheres content 300 g / L, slurry temperature 80°C, filter bottle vacuum 0.02 MPa, filter cake thickness 5 mm.

[0116] Step 7) Ammonium oxalate to catalyst weight ratio 0.10, deionized water temperature 20°C, deionized water to catalyst microspheres weight ratio 10. The filter cake is then removed and the filtrate I collected to give catalyst sample S2 having a sodium oxide content of 1.1% and a filtrate F ammonia nitrogen content of 6 ppm.

[0117] Example 3

[0118] The operating steps are the same as in Example 1, with the exception that:

[0119] Step 1) NaY molecular sieve slurry content 100 g / L, black acid added at a dry weight ratio of 0.05:1 to NaY molecular sieve, slurry temperature 100°C, filter bottle vacuum 0.02 MPa, filter cake thickness 15 mm.

[0120] Step 2) Two-cross-one-calcined rare earth Y molecular sieve mixed with ammonia nitrogen sewage (filtrate I) to give a slurry with 10 times the amount of molecular sieve to filtrate I, slurry temperature 100°C, stirring 0.5 h, filter bottle vacuum 0.02 MPa, filter cake thickness 5 mm.

[0121] Step 3) Ammonium phosphate to molecular sieve weight ratio 0.20 at a temperature of 20°C, deionized water temperature 20°C, deionized water to molecular sieve weight ratio 3. The molecular sieve filter cake is removed and the filtrate J collected.

[0122] Step 4) Molecular sieve: montmorillonite: pseudo-boehmite (calculated as alumina): white carbon black = 35:54:10:1.

[0123] Step 5) Spray drying, solidification.

[0124] Step 6) Catalyst microspheres content 100 g / L, slurry temperature 20°C, filter bottle vacuum 0.08 MPa, filter cake thickness 20 mm.

[0125] Step 7) Ammonium sulfate to catalyst weight ratio 0.005, deionized water temperature 100°C, deionized water to catalyst microspheres weight ratio 7. The filter cake is then removed and the filtrate K collected to give catalyst sample S3 having a sodium oxide content of 1.0% and a filtrate J ammonia nitrogen content of 4 ppm.

[0126] Example 4

[0127] The operating steps are the same as in Example 1, with the exception that:

[0128] Step 1) NaY molecular sieve slurry content is 180 g / L, the amount of added black and yellow humic acid is 0.05:1 of the dry weight of NaY molecular sieve, slurry temperature is 75°C, filter bottle vacuum is 0.04 MPa, filter cake thickness is 8 mm.

[0129] Step 2) (two cross one calcined hydrogen Y molecular sieve + one cross one calcined hydrogen Y molecular sieve) is mixed with ammonia-nitrogen wastewater (filtrate K) for slurry, the amount of filtrate K is 4 times the molecular sieve, slurry temperature is 70°C, stirring time is 1.5 h, filter bottle vacuum is 0.04 MPa, filter cake thickness is 13 mm.

[0130] Step 3) The weight ratio of cerium nitrate (calculated as rare earth oxide) to molecular sieve is 0.05, the temperature of deionized water is 40°C, and the weight ratio of deionized water to molecular sieve is 8. The molecular sieve filter cake is removed and the filtrate L is collected.

[0131] Step 4) Molecular sieve: kaolin: aluminum sol (calculated as aluminum oxide): yttrium oxide = 35:54:10:1.

[0132] Step 5) Spray drying and solidification.

[0133] Step 6) The content of catalyst microspheres is 170 g / L, slurry temperature is 60°C, filter bottle vacuum is 0.04 MPa, filter cake thickness is 18 mm.

[0134] Step 7) The weight ratio of (ammonium oxalate + ammonium bicarbonate) to catalyst is 0.08. The temperature of deionized water is 60°C, and the weight ratio of deionized water to molecular sieve is 9. After the filter cake is dried at 200°C, it is calcined at 500°C for 1 h, then the filter cake is removed and the filtrate M is collected, obtaining catalyst sample S4, the content of sodium oxide is 1.2%, and the ammonia-nitrogen content of filtrate L is 4 ppm.

[0135] From the results of examples S1 to S4, it can be seen that the filtrate obtained by the method of the present application has an ammonia nitrogen content of less than 15 ppm, which meets the national first-level emission standard. Compared with Comparative Example 1, the operation process of the present application is simple and can directly realize the direct discharge of ammonia nitrogen wastewater on the existing catalyst preparation device. In Comparative Example 1, the wastewater generated in the molecular sieve synthesis and exchange process is used as the spray washing liquid of the spray drying tower for the exhaust gas of catalyst spray granulation, the ammonia nitrogen in the spray washing liquid is stripped and absorbed by an ammonia absorption tower, the spray recovery liquid with low ammonia nitrogen content is stirred into a gel by an aluminum salt or an acid liquid, filtered, and the filtrate is discharged; the absorption liquid of the ammonia absorption tower is used as the molecular sieve exchange liquid or the ingredients, the operation is complicated, and the ammonia nitrogen wastewater is still higher than the national first-level emission standard, which cannot meet the direct discharge requirement. Compared with Comparative Example 2, the method of the present application takes into account the feasibility of ammonia nitrogen wastewater treatment and production. Comparative Example 2 needs to be exchanged at a temperature of 0-5°C, the operation condition is harsh, the industrial operation is difficult, and it cannot meet the actual production needs. The FCC catalyst filtrate prepared by the method provided by the present application has low ammonia nitrogen content, does not need to be treated for ammonia nitrogen, can realize direct discharge, has good operability, and has good industrial application prospect.

[0136] Of course, the present application can have other various embodiments, and those skilled in the art can make various corresponding changes and modifications according to the present application without departing from the spirit and essence of the present application, but these corresponding changes and modifications should all belong to the protection scope of the claims of the present application.

Claims

1. A method for preparing a catalytic cracking catalyst, characterized in that, Includes the following steps: 1) Pulp NaY molecular sieve, humic acid and water, filter to form NaY molecular sieve filter cake layer, wherein the dry weight ratio of humic acid to NaY molecular sieve is 0.001-0.05; 2) The Y-type molecular sieve is slurried with ammonia nitrogen wastewater to obtain a Y-type molecular sieve slurry. The Y-type molecular sieve slurry is filtered through a NaY molecular sieve filter cake layer to obtain a composite filter cake layer. Then, it is ion exchanged with a first ammonium salt exchange solution and / or a rare earth exchange solution, and washed with water to obtain a composite molecular sieve filter cake. The Y-type molecular sieve is a one-cross-cross-one-baked Y-type molecular sieve and / or a two-cross-one-baked Y-type molecular sieve. The weight ratio of ammonium salt to the total dry basis of NaY molecular sieve and Y-type molecular sieve in the first ammonium salt exchange solution is 0.1-0.

2. The weight ratio of rare earth in the rare earth exchange solution (calculated as rare earth oxides) to the total dry basis of NaY molecular sieve and Y-type molecular sieve is 0.05-0.

10. 3) The composite molecular sieve filter cake, inorganic oxide, clay, binder and water are mixed and pulped, spray dried and shaped, calcined and cured to obtain catalyst microspheres. The catalyst microspheres are mixed with water, pulped and filtered, ion exchanged with a second ammonium salt exchange solution, washed with water and dried to obtain a catalytic cracking catalyst. The weight ratio of ammonium salt to dry basis of catalyst microspheres in the second ammonium salt exchange solution is 0.005-0.

10.

2. The method for preparing the catalytic cracking catalyst according to claim 1, characterized in that, The sodium oxide content of the NaY molecular sieve is 9-15%.

3. The method for preparing the catalytic cracking catalyst according to claim 1, characterized in that, The humic acid is one or more of fulvic acid, brown humic acid, and black humic acid.

4. The method for preparing the catalytic cracking catalyst according to claim 1, characterized in that, The ammonium salt is one or more of ammonium chloride, ammonium sulfate, ammonium oxalate, ammonium phosphate, and ammonium bicarbonate.

5. The method for preparing the catalytic cracking catalyst according to claim 1, characterized in that, The ammonium salt is ammonium chloride and / or ammonium sulfate.

6. The method for preparing the catalytic cracking catalyst according to claim 1, characterized in that, The rare earth elements are rare earth nitrates and / or chlorides, and the rare earth elements are one or more of lanthanum, cerium, praseodymium, neodymium, and yttrium.

7. The method for preparing the catalytic cracking catalyst according to claim 1, characterized in that, The uni-cross-calcined Y-type molecular sieve is one or more of the following: uni-cross-calcined ultrastable Y molecular sieve, uni-cross-calcined rare earth Y molecular sieve, uni-cross-calcined rare earth hydrogen Y molecular sieve, and uni-cross-calcined hydrogen Y molecular sieve; the di-cross-calcined Y-type molecular sieve is one or more of the following: di-cross-calcined ultrastable Y molecular sieve, di-cross-calcined rare earth Y molecular sieve, di-cross-calcined rare earth hydrogen Y molecular sieve, and di-cross-calcined hydrogen Y molecular sieve.

8. The method for preparing the catalytic cracking catalyst according to claim 1, characterized in that, The inorganic oxide is one or more of rare earth oxide, magnesium oxide and silicon oxide; the clay is one or more of kaolin, halloysite and montmorillonite; the binder is one or more of alumina sol, silica sol and boehmite.

9. The method for preparing the catalytic cracking catalyst according to claim 1, characterized in that, The ammonia nitrogen wastewater in step 2) is the filtrate collected during the ion exchange process in step 2) and / or the filtrate collected during the ion exchange process in step 3).

10. The method for preparing the catalytic cracking catalyst according to claim 1, characterized in that, In step 2), the mass ratio of ammonia nitrogen wastewater to Y-type molecular sieve is 2-10.

11. The method for preparing the catalytic cracking catalyst according to claim 1, characterized in that, In step 2), the mass ratio of ammonia nitrogen wastewater to Y-type molecular sieve is 3-6.

12. The method for preparing the catalytic cracking catalyst according to claim 1, characterized in that, Steps 1) and 2) are performed on a first horizontal belt filter, which includes a NaY molecular sieve cake layer forming zone, a composite cake layer forming zone, an ion exchange zone, and a water washing zone connected in series; Step 3) is performed on a second horizontal belt filter, which includes a cake layer forming zone, an ion exchange zone, and a water washing zone connected in series.

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