Catalytic cracking aid for increasing the production of propylene and butylene and process for its preparation

Abstract

The application discloses a catalytic cracking aid for increasing the yield of propylene and butylene, which comprises 10-75 wt% of molecular sieve based on the dry base weight, 1-20 wt% of zirconium sol based on the dry base weight and 3.0-35 wt% of phosphorus additive based on the dry base weight. The zirconium sol is prepared by a zirconium salt hydrolysis method. The phosphorus additive is added in two steps. A preparation method of the catalytic cracking aid is provided. The catalytic cracking aid can improve the yield and selectivity of propylene and butylene, and reduce the ethylene concentration in dry gas.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of material preparation, and particularly relates to a catalytic cracking aid for increasing production of propylene and butene and a preparation method thereof. BACKGROUND

[0002] Catalytic cracking is an important process for producing liquefied gas, gasoline and diesel oil and other light oil products from heavy petroleum hydrocarbons under the action of a catalyst. The traditional catalytic cracking raw material is heavy distillate oil, mainly straight-run vacuum distillate oil, and also including coking heavy distillate oil. Due to the growing demand for light oil products and technological progress, in recent years, some heavy oil or residual oil has also been used as a catalytic cracking raw material.

[0003] The catalyst used in the initial industrial catalytic cracking device is treated natural active clay, and the main active component thereof is aluminum silicate. Shortly thereafter, natural active clay was replaced by artificially synthesized aluminum silicate. Both of these catalysts are amorphous aluminum silicate. The application of molecular sieve catalysts in catalytic cracking is a major development in catalytic cracking technology. Compared with amorphous aluminum silicate, molecular sieve catalysts have higher selectivity, activity and stability.

[0004] The auxiliary catalysts that play an auxiliary role are added to the catalytic cracking catalyst in the form of additives to make up for some deficiencies of the cracking catalyst. Currently, the existing catalytic aids are used in the catalytic cracking process, and when the amount of the aid added is small, the concentration of low-carbon olefins in liquefied gas is not high; when the amount of the aid added is large, the heavy oil conversion capacity is weakened, and dry gas and coke are increased. SUMMARY

[0005] In order to solve the above problems, the present application provides a catalytic cracking aid and a preparation method thereof.

[0006] The present application provides a catalytic cracking aid, which comprises, based on the dry weight of the aid, 10-75 wt% of a molecular sieve, 1-20 wt% of a zirconium sol, 3-35 wt% of a phosphorus additive, 3-40 wt% of another inorganic binder, and 1-60 wt% of clay, based on the dry weight.

[0007] According to an embodiment of the present application, the preparation method of the above-mentioned zirconium sol is selected from one or more of a zirconium salt hydrolysis method, an alkali addition method, an oxidation method and an ion exchange method.

[0008] According to an embodiment of the present application, the preparation method of the above-mentioned zirconium sol is:

[0009] (1) a zirconium source is prepared into a solution with a certain concentration at room temperature and stirred uniformly, wherein the ZrO2 concentration is 0.5-20 wt% in terms of oxides;

[0010] (2) adding a stabilizer to the above solution in a molar ratio of 1-6 times of zirconium, and stirring at room temperature to 90°C for 0.5-3 hours to allow the reaction to proceed sufficiently, thereby obtaining a first mixed solution;

[0011] (3) slowly adding a lye to the above solution at room temperature to 50°C by using a pump, and controlling the amount of the lye to be added so that the pH of the zirconium sol is 0-10, preferably 1-7, and more preferably 2-5, thereby obtaining a clear and transparent zirconium sol.

[0012] According to an embodiment of the present application, the stabilizer is an organic acid selected from at least one of acetic acid, glycolic acid, oxalic acid, malonic acid, malic acid, tartaric acid, succinic acid, adipic acid, maleic acid, itaconic acid, citric acid, and the like, and preferably acetic acid or citric acid.

[0013] According to an embodiment of the present application, the phosphorus additive is added in two steps.

[0014] According to an embodiment of the present application, the molecular sieve is one or both of an IMF molecular sieve and an MFI molecular sieve.

[0015] Preferably, the molecular sieve is an IMF molecular sieve and an MFI molecular sieve. The use of the IMF molecular sieve and the MFI molecular sieve can improve the yield and selectivity of propylene and butylene in the liquefied gas.

[0016] According to an embodiment of the present application, the mass ratio of the IMF molecular sieve to the MFI molecular sieve is 0.01-100, preferably 0.1-30, and more preferably 0.25-9.

[0017] According to an embodiment of the present application, the IMF molecular sieve is one or more selected from hydrogen-type IM-5, phosphorus-containing IM-5, and phosphorus- and transition metal-containing IM-5 molecular sieves; and the MFI molecular sieve is one or more selected from hydrogen-type MFI molecular sieves, phosphorus-containing MFI molecular sieves, and phosphorus- and transition metal-containing MFI molecular sieves.

[0018] According to an embodiment of the present application, the additive further comprises 3-40% by weight of an inorganic binder based on the dry weight, and 1-60% by weight of clay based on the dry weight.

[0019] Preferably, the other inorganic binder is one or more selected from pseudoboehmite, acidified alumina, aluminum sol, silica-alumina sol, and water glass; and / or

[0020] The clay is one or more selected from kaolin, sepiolite, attapulgite, rectorite, montmorillonite, and diatomite.

[0021] The present application provides a preparation method of the above-mentioned catalytic cracking additive, and the specific preparation steps are as follows:

[0022] (1) adding molecular sieve into part of the phosphorus additive to prepare a slurry;

[0023] (2) mixing the slurry with other inorganic binders, zirconium sol and clay slurry, beating, and spray drying;

[0024] (3) after spray drying, introducing the remaining phosphorus additive;

[0025] (4) drying and calcining.

[0026] According to one embodiment of the present application, the phosphorus additive added before spray drying is 1-10% by weight, and the phosphorus additive added after spray drying is 2-24% by weight, based on the dry weight of the aid.

[0027] According to one embodiment of the present application, the phosphorus additive can be selected from one or more of phosphorus compounds, such as inorganic and organic compounds containing phosphorus, which can be easily soluble in water, or hardly soluble or insoluble in water, such as one or more of phosphorus oxides, phosphoric acid, orthophosphates, phosphites, hypophosphites, basic phosphates, acid phosphates, and organic compounds containing phosphorus. The preferred phosphorus compound is one or more of phosphoric acid, ammonium phosphate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate and aluminum phosphate; more preferably, the phosphorus additive is diammonium hydrogen phosphate.

[0028] In the obtained aid, the phosphorus additive added before spray drying is in the form of a phosphorus compound (such as phosphorus oxides, orthophosphates, phosphites, basic phosphates and acid phosphates). The phosphorus additive can exist in any possible position of the aid, such as in the pores of the zeolite, on the surface of the zeolite, and in the matrix material; the phosphorus additive added after spray drying is in the form of a phosphorus compound, which mainly exists in the matrix material. The types of the phosphorus additive added before and after spray drying can be the same or different.

[0029] The two-step addition of the phosphorus additive reduces the interaction between phosphorus and Al in the matrix.

[0030] According to one embodiment of the present application, the drying temperature is room temperature to 400°C, preferably 100-300°C; the calcining temperature is 400-700°C, and the calcining time is 0.5-100 hours, preferably 0.5-10 hours.

[0031] Inventive effects:

[0032] The phosphorus additive is added in two steps, and zirconium sol is used to reduce the interaction between phosphorus and the substrate AL, thereby reducing dry gas and coke and lowering the abrasion intensity. The FCC aid provided by the application can improve the yield and selectivity of propylene and butylene and reduce the ethylene concentration in dry gas through the synergistic effect of the components. DETAILED DESCRIPTION

[0033] The detailed description of the specific embodiments of the present disclosure is described below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure, and are not used to limit the present disclosure.

[0034] The preparation method of the FCC aid provided by the application comprises the following steps: slurry of the IMF structure molecular sieve and the MFI molecular sieve is prepared, and a part of the phosphorus additive is added; then the inorganic binder, clay and the molecular sieve slurry are mixed and slurry, and the order of feeding is not particularly required. Preferably, the clay and the molecular sieve slurry are mixed first, and then the inorganic binder is mixed and slurry, which can avoid the reaction between the phosphorus compound and the aluminum stone in the inorganic binder, thereby improving the activity and selectivity of the aid.

[0035] The preparation method of the FCC aid provided by the application further comprises the step of spray drying the slurry obtained by the slurry. The spray drying method is well known to those skilled in the art, and the present application does not have special requirements.

[0036] The FCC aid provided by the application is suitable for catalytic cracking of various hydrocarbon oils. When used in the catalytic cracking process, it can be added alone to the catalytic cracking reactor or mixed with the catalytic cracking catalyst. Generally, the aid provided by the application accounts for not more than 30% by weight of the total amount of the mixture of the FCC catalyst and the aid provided by the application, preferably 1-25% by weight, more preferably 3-15% by weight, and the hydrocarbon oil is selected from one or more of various petroleum fractions, such as crude oil, atmospheric residue, vacuum residue, atmospheric wax oil, vacuum wax oil, straight-run wax oil, propane light / heavy deoiled, coking wax oil and coal liquefaction products.

[0037] The FCC aid provided by the application is used in the catalytic cracking process, and the hydrocarbon oil catalytic cracking conditions can be conventional catalytic cracking conditions. Generally, the hydrocarbon oil catalytic cracking conditions include a reaction temperature of 400-600°C, preferably 450-550°C, a weight hourly space velocity of 8-120 h-1, preferably 8-80 h-1, and a catalyst / oil ratio (weight ratio) of 1-20, preferably 3-15. The FCC aid provided by the application can be used in various existing catalytic cracking reactors, such as in fixed bed reactors, fluidized bed reactors, riser reactors, multi-reaction zone reactors, etc.

[0038] The present disclosure is further illustrated by the following examples, but the present disclosure is not limited in any way by the examples. The instruments and reagents used in the examples are conventional for those skilled in the art, unless otherwise specified.

[0039] The adjuvant of the present disclosure is evaluated by using an ACE device when used for catalytic cracking reaction performance evaluation.

[0040] The RIPP standard method described in the present disclosure can be specifically referred to in "Analysis Methods for Petroleum and Chemical Industry", edited by Yang Cuiding et al., 1990 edition.

[0041] The properties of some raw materials used in the examples are as follows:

[0042] Pseudo-boehmite is an industrial product produced by Shandong Aluminum Company, with a solid content of 60% by weight;

[0043] Aluminum sol is an industrial product produced by Qilu Branch of Sinopec Catalyst, with an Al2O3 content of 21.5% by weight;

[0044] Kaolin is a special kaolin for catalytic cracking catalyst produced by Suzhou Kaolin Company, with a solid content of 78% by weight.

[0045] Hydrochloric acid: chemically pure, with a concentration of 36-38% by weight, produced by Beijing Chemical Plant.

[0046] ZRP-5: an industrial product produced by Qilu Branch of Sinopec Catalyst, with a P2O5 content of 4.12% and a crystallinity of 75%.

[0047] P-IM-5: H-IM-5 molecular sieve with a silicon-aluminum ratio of 27 is impregnated with a 0.2 mol / L ammonium dihydrogen phosphate solution by the saturation impregnation method, stirred for two hours, dried at 120°C for 10 hours, and calcined at 500°C for 3 hours to obtain phosphorus-modified IM-5 molecular sieve P-IM-5, with a P2O5 content of 4.23% by mass and a crystallinity of 78%.

[0048] Preparation Examples 1-3 are zirconium sol preparation examples

[0049] Preparation Example 1:

[0050] (1) Zirconium sol preparation: 130 g of deionized water was added to a beaker, followed by the addition of 125 g of zirconium oxychloride, stirring for 10 min, slowly adding 50 g of acetic acid, and stirring for 30 min to obtain a mixed solution; then, 25% concentrated ammonia water was slowly added to the above solution at a pump speed of 1.5 times / min, and the pH was controlled at 2.5 to obtain a clear and transparent zirconium sol ZM-1.

[0051] Preparation Example 2:

[0052] (1) Zirconium sol preparation: 130 g of deionized water was added into a beaker, then 125 g of zirconium oxychloride was added, stirred for 10 min, 38 g of oxalic acid was slowly added, stirred for 30 min, to obtain a mixed solution; then slowly add ammonia water to the above solution with a pump, the pump speed was controlled at 1.5 times / min, the PH was controlled at 2.5, to obtain a clear and transparent zirconium sol ZM-2.

[0053] Preparation Example 3:

[0054] (1) Zirconium sol preparation: 130 g of deionized water was added into a beaker, then 125 g of zirconium oxychloride was added, stirred for 10 min, 38 g of oxalic acid was slowly added, stirred for 30 min, to obtain a mixed solution; then slowly add ammonia water to the above solution with a pump, the pump speed was controlled at 1.5 times / min, the PH was controlled at 2.5, to obtain a clear and transparent zirconium sol ZM-2.

[0055] Catalyst Example 1:

[0056] (1) Take molecular sieve ZRP-5, P-IM-5 respectively, add deionized water to pulp for 10 min, add diammonium hydrogen phosphate (a), pulp for 120 min, to obtain molecular sieve slurry A, B; add kaolin, aluminum sol, zirconium sol and acidified aluminum stone to deionized water to pulp for 20 min, add molecular sieve slurry A, B under stirring, then continue to pulp for 45 min, spray dry the obtained slurry to obtain microspheres.

[0057] (2) According to the method of saturated immersion, first measure the water absorption rate of the microspheres, then dissolve the remaining diammonium hydrogen phosphate (b) in water, slowly add it to the microspheres, stir evenly, stand at room temperature for 4 h, and calcine at 500℃ for 2 h to obtain CAT-1, the specific ratio is shown in Table 2.

[0058] Examples 2-5: The same as the steps of Example 1, the specific ratio is shown in Table 2.

[0059] Comparative Example 1:

[0060] (1) Take molecular sieve ZRP-5, kaolin and acidified aluminum stone, add deionized water and aluminum sol to pulp for 120 min, add hydrochloric acid to adjust the pH value of the slurry to 3.0, then continue to pulp for 45 min, spray dry the obtained slurry to obtain microspheres;

[0061] (2) According to the method of saturated immersion, first measure the water absorption rate of the microspheres, then dissolve the remaining diammonium hydrogen phosphate (b) in water, slowly add it to the microspheres, stir evenly, stand at room temperature for 4 h, and calcine at 500℃ for 2 h to obtain CAT-1, the specific ratio is shown in Table 2.

[0062] Comparative Example 2:

[0063] (1) Take molecular sieve ZRP-5, P-IM-5 molecular sieve, kaolin and acidified alumina, add deionized water and alumina sol, and pulp for 120 minutes, then continue to pulp for 45 minutes, spray dry the obtained slurry to obtain microspheres;

[0064] (2) According to the method of saturated impregnation, first measure the water absorption rate of the microspheres, then dissolve diammonium hydrogen phosphate in water, slowly add it to the microspheres, stir uniformly, stand at room temperature for 4h, and calcine at 500℃ for 2h to obtain DCAT-3, the ratio of which is shown in Table 1.

[0065] Comparative Example 3:

[0066] (1) Take molecular sieve ZRP-5, P-IM-5 molecular sieve, kaolin and acidified alumina, add deionized water and alumina sol, and pulp for 120 minutes, then continue to pulp for 45 minutes, spray dry the obtained slurry to obtain microspheres;

[0067] (2) According to the method of saturated impregnation, first measure the water absorption rate of the microspheres, then dissolve diammonium hydrogen phosphate in water, slowly add it to the microspheres, stir uniformly, stand at room temperature for 4h, and calcine at 500℃ for 2h to obtain DCAT-3, the ratio of which is shown in Table 1.

[0068] Comparative Example 4:

[0069] (1) Take molecular sieve ZRP-5, P-IM-5 molecular sieve, kaolin and acidified alumina, add deionized water and alumina sol, and pulp for 120 minutes, then continue to pulp for 45 minutes, spray dry the obtained slurry to obtain microspheres;

[0070] (2) According to the method of saturated impregnation, first measure the water absorption rate of the microspheres, then dissolve diammonium hydrogen phosphate in water, slowly add it to the microspheres, stir uniformly, stand at room temperature for 4h, and calcine at 500℃ for 2h to obtain DCAT-3, the ratio of which is shown in Table 1.

[0071] Table 1

[0072]

[0073] The following examples take a fixed fluidized bed reactor as an example to illustrate the cracking reaction effect of the cracking aid provided by the present application.

[0074] The FCC catalysts SLA and CAT-1 to 5 and DCAT 1 to 4 were aged at 800°C under 100% steam for 17 hours. Different amounts of the aged catalysts were mixed with SLA (the main properties of which are shown in Table 2) and the catalyst mixtures were charged into the reactor of a small fixed fluidized bed reactor for catalytic cracking of the feedstocks shown in Table 3. The results of the reactions are shown in Table 4. The reaction conditions were: reaction temperature 530°C, catalyst to oil ratio 4, space velocity 16h -1 .

[0075] Table 2 Main properties of SLA

[0076]

[0077] Table 3 Properties of feedstocks for evaluation

[0078]

[0079]

[0080] Table 4 Results of evaluation

[0081]

[0082]

[0083] As can be seen from Table 4, the catalytic aid provided by the present application can effectively increase the yield of catalytic cracking liquefied gas, significantly increase the concentration of propylene and butene in the catalytic cracking liquefied gas, greatly improve the selectivity of low-carbon olefins, and at the same time, the concentration of ethylene in dry gas is reduced, as compared with the reference aid.

Claims

1. A catalytic cracking aid, the aid comprising, on a dry basis, 10-75 wt% of molecular sieves, 1-20 wt% of zirconium sol, 3-35 wt% of phosphorus additive, 3-40 wt% of other inorganic binder, 1-60 wt% of clay, based on the dry weight of the aid. The molecular sieves are IMF molecular sieves and MFI molecular sieves, and the mass ratio of the IMF molecular sieves to the MFI molecular sieves is 0.01-100. The phosphorus additive is added in two steps, and the amount of the phosphorus additive added before spraying of the aid is 3-10 wt%, and the amount of the phosphorus additive added after spraying of the aid is 10-24 wt%, based on the dry weight of the aid. The other inorganic binder is selected from one or more of pseudoboehmite, acidified alumina, aluminum sol and silica-alumina sol; and / or The clay is selected from one or more of kaolin, sepiolite, attapulgite, rectorite and montmorillonite; The preparation method of the zirconium sol is: (1) a zirconium source is prepared into a solution of a certain concentration at room temperature, and stirred uniformly; the ZrO2 concentration is 0.5-20 wt%, based on the oxide; (2) a stabilizer is added to the above solution in a molar ratio of 1-6 times that of zirconium, and stirred at room temperature to 90°C for 0.5-3 hours to make it fully react, to obtain a first mixed solution; (3) under the condition of room temperature to 50°C, the above solution is slowly added with a pump, and the amount of the lye is controlled so that the pH of the zirconium sol is 0-10, to obtain a clear and transparent zirconium sol.

2. The adjuvant according to claim 1, characterized in that, In the step (3) of the preparation method of the zirconium sol, the amount of the lye is controlled so that the pH of the zirconium sol is 1-7, to obtain a clear and transparent zirconium sol.

3. The adjuvant of claim 1, wherein, In the step (3) of the preparation method of the zirconium sol, the amount of the lye is controlled so that the pH of the zirconium sol is 2-5, to obtain a clear and transparent zirconium sol.

4. The adjuvant of claim 1, wherein, The mass ratio of the IMF molecular sieves to the MFI molecular sieves is 0.1-30.

5. The adjuvant according to claim 4, characterized in that, The mass ratio of the IMF molecular sieves to the MFI molecular sieves is 0.25-9.

6. The adjuvant of claim 1, wherein, The IMF molecular sieves are selected from one or more of hydrogen type IM-5, phosphorus-containing IM-5 and phosphorus-containing and transition metal-containing IM-5 molecular sieves; and the MFI molecular sieves are selected from one or more of hydrogen type MFI molecular sieves, phosphorus-containing MFI molecular sieves, phosphorus-containing and transition metal-containing MFI molecular sieves.

7. Process for the preparation of the adjuvant according to any one of claims 1 to 6, characterized in that, The specific preparation steps are: (1) the molecular sieves are added with part of the phosphorus additive to prepare a slurry; (2) the slurry, other inorganic binder, zirconium sol and clay slurry are mixed, beaten and spray dried; (3) after spray drying and forming, the remaining phosphorus additive is introduced; (4) drying and calcination.

8. The preparation method according to claim 7, characterized in that, The phosphorus additive is selected from a compound of phosphorus.

9. The production method according to claim 8, characterized by, The phosphorus additive is selected from one or more of oxides of phosphorus, orthophosphates, phosphites, hypophosphites, basic phosphates, acid phosphates and phosphorus-containing organic compounds.

10. The preparation method according to claim 8, characterized in that, The phosphorus additive is one or more of phosphoric acid, ammonium phosphate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate and aluminum phosphate.

11. The preparation method according to claim 7, characterized in that, The drying temperature is room temperature to 400°C; the calcination temperature is 400-700°C, and the calcination time is 0.5-100 hours.

12. The method of claim 11, wherein, The drying temperature is 100-300°C; and the calcination time is 0.5-10 hours.

13. A catalyst comprising the promoter of any one of claims 1-6 or prepared according to the method of any one of claims 7-12.

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