A method for catalytic cracking reaction
By using ZSM-5/Y composite molecular sieve as a catalyst and using its core-shell structure, the problem of low cracking efficiency of polycyclic aromatic hydrocarbons when treating heavy oil is solved, and efficient raw material conversion and low carbon selectivity are achieved.
Patent Information
- Application Number
- CN202111103676.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-09-17
- Publication Date
- 2025-05-13
- Estimated Expiration
- 2041-09-17
AI Technical Summary
How to more efficiently process heavy oils mined in the future, improve the gasoline yield and octane number in the FCC process, and increase the yield of low-carbon olefins, and solve the problem of cracking efficiency of polycyclic aromatic hydrocarbons in heavy oils.
The catalytic cracking reaction method is adopted with ZSM-5/Y composite molecular sieve as a catalyst. By contacting the ZSM-5/Y composite molecular sieve with heavy oil raw materials, the catalytic activity and selectivity are improved by using the core-shell structure of ZSM-5 molecular sieve particles and Y molecular sieve particles.
It has achieved a high raw material conversion rate, high low carbon selectivity and low carbon deposit amount, which is suitable for catalytic cracking reaction of heavy oil raw materials.
Smart Images
Figure CN115926833B_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the field of catalytic cracking reaction, and in particular, to a method for catalytic cracking reaction. Background Art
[0002] As a basic technology in the oil refining industry, catalytic cracking technology plays an irreplaceable role in the development and production of petrochemical products. Since 1962, various modified Y zeolites have been applied to the FCC process as the main active component. The introduction of zeolite catalysts in the FCC process not only greatly improved the catalytic activity, but also significantly increased the output of high value-added products. It is a milestone in the history of the development of the oil refining industry and zeolite chemistry. In order to further improve the yield and octane number of FCC process gasoline and increase the yield of low-carbon olefins, in the 1970s, Mobil Oil Company invented ZSM-5 zeolite and used it as an additive in FCC catalysts on a large scale.
[0003] In the future, there will be more and more heavy oil and less and less light oil in the crude oil produced. How to process heavy oil more efficiently has become a problem that the oil refining industry has to face. As the core of the current oil refining industry, the FCC process will inevitably remain the most important technology for lightening heavy oil and producing gasoline for a long time in the future. The heavier crude oil means that more and larger polycyclic aromatic hydrocarbons need to be cracked during the FCC process, which inevitably involves issues such as the diffusion efficiency of the FCC catalyst and the accessibility of the acid site.
[0004] Although there are many reports on the synthesis methods of isomorphous and heteromorphic composite molecular sieves, there are few reports on composite molecular sieves with ZSM-5 as the core and Y molecular sieve as the shell. It is necessary to further explore the synthesis method of composite molecular sieves with ZSM-5 as the core and Y molecular sieve as the shell. Summary of the invention
[0005] The purpose of the present disclosure is to provide a method for catalytic cracking reaction, which uses ZSM-5 / Y composite molecular sieve as a catalyst, has a higher feedstock conversion rate, a higher low-carbon selectivity and a lower carbon deposition amount, and is suitable for heavy oil feedstock.
[0006] In order to achieve the above object, the present disclosure provides a method for catalytic cracking reaction, the method comprising:
[0007] Contacting the ZSM-5 / Y composite molecular sieve with the heavy oil feedstock to carry out the catalytic cracking reaction;
[0008] Wherein, the ZSM-5 / Y composite molecular sieve comprises ZSM-5 molecular sieve particles and Y molecular sieve particles, and the Y molecular sieve particles are coated on the surface of the ZSM-5 molecular sieve particles;
[0009] The specific surface area of the ZSM-5 / Y composite molecular sieve is 350-740m 2 / g, with a total pore volume of 0.15-0.38cm 3 / g, the pore volume of micropores is 0.14-0.34cm 3 / g, and the pore volume of the mesopores is 0.03-0.09cm 3 / g.
[0010] Optionally, the heavy oil feedstock is selected from one or more of hydrogenated diesel, hydrogenated naphtha, atmospheric residue, hydrogenated VGO and heavy naphtha.
[0011] Optionally, in the catalytic cracking reaction, the reaction temperature is 500-580°C, and the catalyst-oil ratio is 1:(0.5-3).
[0012] Optionally, the reactor for the catalytic cracking reaction is selected from one or more of a fixed bed reactor, a riser reactor, a fluidized bed reactor and a fixed bed microreactor.
[0013] Optionally, the specific surface area of the ZSM-5 / Y composite molecular sieve is 490-680m 2 / g, with a total pore volume of 0.25-0.38cm 3 / g, the pore volume of micropores is 0.20-0.27cm 3 / g, and the pore volume of the mesopores is 0.03-0.09cm 3 / g.
[0014] Optionally, in the ZSM-5 / Y composite molecular sieve, the mass ratio of the ZSM-5 molecular sieve particles to the Y molecular sieve particles is 0.1-3.
[0015] Optionally, the method further comprises preparing the ZSM-5 / Y composite molecular sieve by the following steps:
[0016] Mixing the ZSM-5 molecular sieve and the NaY molecular sieve mother liquor to obtain a mixed material, and performing a first crystallization treatment on the mixed material;
[0017] The mass ratio of the ZSM-5 molecular sieve to the NaY molecular sieve mother liquor is (0.01-0.5):1; the conditions of the first crystallization treatment include: a temperature of 90-120° C. and a time of 10-40 hours.
[0018] Optionally, the method further comprises:
[0019] Before mixing the ZSM-5 molecular sieve with the NaY molecular sieve mother liquor, the ZSM-5 molecular sieve is subjected to an alkali treatment, wherein the alkali treatment comprises: contacting the ZSM-5 molecular sieve with an alkali solution; the alkali treatment temperature is 120-200° C., and the time is 1-5 hours;
[0020] The concentration of the alkaline solution is 0.2-0.8 mol / L, and the alkali in the alkaline solution includes one or more of NaOH, TEAOH and TPAOH; the alkali and SiO 2 The molar ratio of the ZSM-5 molecular sieve is (0.1-0.5):1.
[0021] Optionally, the method further comprises: filtering, washing, ammonium exchanging, first drying and first calcining the pre-product obtained by the first crystallization treatment;
[0022] Optionally, the first drying conditions include: temperature of 90-120° C., time of 4-30 h;
[0023] The first calcination is carried out in an air atmosphere and / or a water vapor atmosphere, the temperature of the first calcination is 400-800° C., and the time is 0.5-8 hours.
[0024] Optionally, the method further comprises preparing the NaY molecular sieve mother solution by the following steps:
[0025] S1, mixing a first alkali source, a first aluminum source and a first silicon source and aging the mixture to prepare a NaY structure directing agent;
[0026] S2, mixing the NaY structure directing agent with NaOH, a second aluminum source, a second silicon source and deionized water to obtain the NaY molecular sieve mother solution;
[0027] Wherein, the first alkali source in terms of alkali metal oxide, 2 O 3 The first aluminum source is SiO 2 The molar ratio of the first silicon source is (10-18):1:(10-18);
[0028] Al 2 O 3 The second aluminum source is Na 2 O, the NaOH, SiO 2 The molar ratio of the second silicon source to the deionized water is 1:(1-3):(3-9):(150-240), based on the total weight of the NaY molecular sieve mother liquor, and calculated in terms of weight percentage, Al 2 O 3 The added amount of the NaY structure directing agent is 1-10 wt %;
[0029] Optionally, the first silicon source and the second silicon source independently include one or more of water glass, silica gel, silicon dioxide, white carbon black and silicate;
[0030] The first aluminum source and the second aluminum source independently include one or more of sodium aluminate, aluminum hydroxide, pseudo-boehmite, SB powder, aluminum sulfate, aluminum alcoholate and aluminum oxide;
[0031] The first alkali source includes one or more of sodium metaaluminate, sodium hydroxide and potassium hydroxide;
[0032] Optionally, the aging time is 8-30h.
[0033] Optionally, the method further comprises preparing the ZSM-5 molecular sieve by the following steps:
[0034] S1, mixing NaOH, a third silicon source, a third aluminum source, a seed crystal and deionized water to obtain a ZSM-5 molecular sieve mother liquor, wherein the ZSM-5 molecular sieve mother liquor does not contain a template agent;
[0035] S2, performing a second crystallization treatment on the ZSM-5 molecular sieve mother liquor;
[0036] The conditions of the second crystallization treatment include: a time of 10-30 hours and a temperature of 170-200°C;
[0037] Among them, Al 2 O 3 The third aluminum source is calculated as Na 2 O, the NaOH, SiO 2 The molar ratio of the third silicon source to deionized water is 1:(0.2-11):(20-50):(230-1200), based on the total weight of the ZSM-5 molecular sieve mother liquor, and the SiO 2 The amount of the seed crystal added is 5-30% by weight;
[0038] Optionally, the third silicon source includes one or more of water glass, silica gel, silicon dioxide, white carbon black and silicate;
[0039] The third aluminum source includes one or more of sodium aluminate, pseudo-boehmite, SB powder, aluminum alcoholate, aluminum oxide, aluminum hydroxide and aluminum sulfate;
[0040] The seed crystals include one or more ZSM-5 molecular sieve seed crystals with a silicon-aluminum ratio of 20-50.
[0041] Optionally, the method further comprises: filtering, washing, ammonium exchanging, second drying and second calcining the primary product obtained by the second crystallization treatment;
[0042] Optionally, the second drying conditions include: temperature of 90-120° C., time of 4-30 h;
[0043] The second calcination conditions include: temperature of 400-800° C. and time of 0.5-8 h.
[0044] Through the above technical scheme, the method uses ZSM-5 / Y composite molecular sieve as a catalyst. The composite molecular sieve has a special structure in which Y molecular sieve particles are completely or partially coated on the surface of ZSM-5 molecular sieve particles. When it is used for catalytic cracking reactions of heavy oil, a higher raw material conversion rate, a higher low-carbon selectivity and a lower carbon deposition amount can be obtained.
[0045] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS
[0046] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:
[0047] Figure 1 It is the X-ray diffraction spectrum of ZSM-5 / Y composite molecular sieves A1, D1 and D2 prepared in Example 1, Comparative Example 1 and Comparative Example 2 of the present application.
[0048] Figure 2 This is a scanning electron microscope image of the ZSM-5 / Y composite molecular sieve A1 prepared in Example 1 of the present application.
[0049] Figure 3 It is the X-ray diffraction spectrum of ZSM-5 / Y composite molecular sieves A2 and A3 prepared in Examples 2 and 3 of the present application.
[0050] Figure 4 This is a scanning electron microscope image of the ZSM-5 / Y composite molecular sieve A2 prepared in Example 2 of the present application.
[0051] Figure 5 This is a scanning electron microscope image of the ZSM-5 / Y composite molecular sieve A3 prepared in Example 3 of the present application.
[0052] Figure 6 These are the nitrogen adsorption and desorption curves of the ZSM-5 / Y composite molecular sieves A2 and A3 prepared in Examples 2 and 3 of the present application.
[0053] Figure 7It is the X-ray diffraction spectrum of ZSM-5 / Y composite molecular sieves A4 and A5 prepared in Examples 4 and 5 of the present application.
[0054] Figure 8 This is a scanning electron microscope image of the ZSM-5 / Y composite molecular sieve A4 prepared in Example 4 of the present application.
[0055] Fig. 9 This is a scanning electron microscope image of the ZSM-5 / Y composite molecular sieve A5 prepared in Example 5 of the present application.
[0056] Fig.10 This is a scanning electron microscope image of the ZSM-5 / Y composite molecular sieve D1 prepared in Comparative Example 1 of the present application. DETAILED DESCRIPTION
[0057] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.
[0058] The present disclosure provides a method for catalytic cracking reaction, the method comprising:
[0059] Contacting the ZSM-5 / Y composite molecular sieve with the heavy oil feedstock to carry out the catalytic cracking reaction;
[0060] Wherein, the ZSM-5 / Y composite molecular sieve comprises ZSM-5 molecular sieve particles and Y molecular sieve particles, and the Y molecular sieve particles are coated on the surface of the ZSM-5 molecular sieve particles;
[0061] The specific surface area of the ZSM-5 / Y composite molecular sieve is 350-740m 2 / g, with a total pore volume of 0.15-0.38cm 3 / g, the pore volume of micropores is 0.14-0.34cm 3 / g, and the pore volume of the mesopores is 0.03-0.09cm 3 / g.
[0062] In the present disclosure, "Y molecular sieve particles are coated on the surface of ZSM-5 molecular sieve particles" means that the surface of ZSM-5 molecular sieve particles is completely coated by Y molecular sieve particles, or the surface of ZSM-5 molecular sieve particles is partially coated by Y molecular sieve particles.
[0063] The ZSM-5 / Y composite molecular sieve disclosed in the present invention is suitable for heavy oil feedstock, which may be selected from one or more of hydrogenated diesel, hydrogenated naphtha, atmospheric residue, hydrogenated VGO and heavy naphtha.
[0064] In one embodiment of the present disclosure, the reactor for the catalytic cracking reaction is selected from one or more of a fixed bed reactor, a riser reactor, a fluidized bed reactor and a fixed bed microreactor.
[0065] In one embodiment of the present disclosure, the specific surface area of the ZSM-5 / Y composite molecular sieve is 490-680m 2 / g, with a total pore volume of 0.25-0.38cm 3 / g, the pore volume of micropores is 0.20-0.27cm 3 / g, and the pore volume of the mesopores is 0.03-0.09cm 3 / g; Further preferably, the specific surface area of the ZSM-5 / Y composite molecular sieve is 560-680m 2 / g, with a total pore volume of 0.31-0.37 cm 3 / g, the pore volume of micropores is 0.20-0.27cm 3 / g, and the pore volume of the mesopores is 0.03-0.09cm 3 / g. The ZSM-5 / Y composite molecular sieve that meets the above range has more excellent diffusion performance and carbon deposition yield. Among them, mesopores refer to pores with a pore size in the range of 2-50nm, and micropores refer to pores with a pore size less than 2nm.
[0066] In one embodiment of the present disclosure, the average particle size of the ZSM-5 / Y composite molecular sieve is 0.5-10 μm.
[0067] In one embodiment of the present disclosure, in the ZSM-5 / Y composite molecular sieve, the mass ratio of the ZSM-5 molecular sieve particles to the Y molecular sieve particles is 0.1-3, preferably 0.5-1.
[0068] In the present application, the mass ratio of ZSM-5 molecular sieve particles to Y molecular sieve particles is calculated based on the feed ratio of each substance during preparation.
[0069] In one embodiment of the present disclosure, in the catalytic cracking reaction, the reaction temperature is 500-580°C, preferably 530-550°C; the catalyst-oil ratio is 1:(0.5-3), preferably 1:(0.5-2). In this application, the catalyst-oil ratio refers to the mass ratio of the ZSM-5 / Y composite molecular sieve to the feed oil.
[0070] In one embodiment of the present disclosure, the method further adopts the following steps to prepare the ZSM-5 / Y composite molecular sieve:
[0071] The ZSM-5 molecular sieve and the NaY molecular sieve mother liquor are mixed to obtain a mixed material, and the mixed material is subjected to a first crystallization treatment;
[0072] Among them, the mass ratio of ZSM-5 molecular sieve to NaY molecular sieve mother liquor is (0.01-0.5):1, preferably (0.05-0.3); and further preferably (0.1-0.25):1.
[0073] In one embodiment of the present disclosure, the conditions of the first crystallization treatment include: temperature of 90-120° C., time of 10-40 h; preferably, temperature of 95-100° C., time of 24-30 h.
[0074] In one embodiment of the present disclosure, the method further comprises:
[0075] Before mixing the ZSM-5 molecular sieve with the NaY molecular sieve mother liquor, the ZSM-5 molecular sieve is subjected to an alkali treatment; the alkali treatment comprises: contacting the ZSM-5 molecular sieve with an alkali solution; wherein the alkali treatment temperature is 120-200°C, and the alkali treatment time is 1-5h; the concentration of the alkali solution is 0.2-0.8 mol / L, preferably 0.3-0.7 mol / L, and more preferably 0.4-0.6 mol / L. The alkali solution can be an aqueous solution, and the alkali in the alkali solution includes one or more of NaOH, TEAOH and TPAOH; the alkali and SiO 2 The molar ratio of ZSM-5 molecular sieve is (0.1-0.5): 1, preferably (0.1-0.3): 1. The alkali-treated ZSM-5 molecular sieve can not only remove part of silicon and aluminum, providing part of silicon source and aluminum source for the growth of NaY shell layer, but also can be fully mixed with NaY molecular sieve mother liquor, which is beneficial to the growth of shell layer.
[0076] In one embodiment of the present disclosure, the method further includes: filtering, washing, ammonium exchange, first drying and first calcining the pre-product obtained by the first crystallization treatment. The above operations are conventional in the art and are not specifically required. For example, the conditions for the first drying include: a temperature of 90-120°C and a time of 4-30h; preferably, a temperature of 110-120°C and a time of 10-16h. The first calcination is carried out in an air atmosphere and / or a water vapor atmosphere at a temperature of 400-800°C and a time of 0.5-8h; preferably, a temperature of 450-600°C and a time of 3-5h. Among them, air atmosphere refers to direct calcination in a muffle furnace, and water vapor atmosphere refers to calcination under a steam atmosphere.
[0077] In one embodiment of the present disclosure, the method further comprises preparing a NaY molecular sieve mother solution by the following steps:
[0078] S1, mixing a first alkali source, a first aluminum source and a first silicon source and aging the mixture to prepare a NaY structure directing agent;
[0079] S2, mixing the NaY structure directing agent with NaOH, a second aluminum source, a second silicon source and deionized water to obtain a NaY molecular sieve mother solution;
[0080] Among them, the first alkali source in terms of alkali metal oxide, the first alkali source in terms of Al 2 O 3 The first aluminum source is SiO 2 The molar ratio of the first silicon source is (10-18):1:(10-18); preferably (15-18):1:(15-18).
[0081] In one embodiment of the present disclosure, Al 2 O 3 The second aluminum source is Na 2 O-based NaOH, SiO 2 The molar ratio of the second silicon source to deionized water is 1:(1-3):(3-9):(150-240); preferably 1:(2-3):(5-9):(150-210).
[0082] In one embodiment of the present disclosure, based on the total weight of the NaY molecular sieve mother liquor, the Al 2 O 3 The added amount of the NaY structure directing agent is 1-10 wt %, for example, 5 wt %.
[0083] In one embodiment of the present disclosure, the aging time is 8-30 hours, preferably 24-30 hours.
[0084] In one embodiment of the present disclosure, the method further comprises preparing the ZSM-5 molecular sieve by the following steps:
[0085] S1, mixing NaOH, a third silicon source, a third aluminum source, a seed crystal and deionized water to obtain a ZSM-5 molecular sieve mother liquor, wherein the ZSM-5 molecular sieve mother liquor does not contain a template agent;
[0086] S2, performing a second crystallization treatment on the ZSM-5 molecular sieve mother liquor;
[0087] Among them, Al 2 O 3 The third aluminum source in terms of alkali metal oxide, the NaOH in terms of SiO 2 The molar ratio of the third silicon source to deionized water is 1:(0.2-11):(20-50):(230-1200), preferably 1:(2-5):(30-50):(300-500).
[0088] In one embodiment of the present disclosure, the seed crystals include one or more ZSM-5 molecular sieve seed crystals having a silicon-to-aluminum ratio of 20-50.
[0089] In one embodiment of the present disclosure, based on the total weight of the ZSM-5 molecular sieve mother liquor, SiO 2 The amount of seed crystals added is 5-30% by weight, preferably 5-10% by weight.
[0090] In one embodiment of the present disclosure, the first silicon source, the second silicon source and the third silicon source are the same or different, and independently include one or more of water glass, silica gel, silicon dioxide, white carbon black and silicate; preferably silica gel and / or water glass. Among them, the silicate can be, for example, sodium silicate. Specifically, the first silicon source can be water glass, the second silicon source can be water glass, and the third silicon source can be silica gel.
[0091] In one embodiment of the present disclosure, the first aluminum source, the second aluminum source and the third aluminum source are the same or different, and independently include one or more of sodium aluminate, SB powder, aluminum alcoholate, aluminum oxide, aluminum hydroxide, aluminum alcoholate and aluminum sulfate; preferably sodium aluminate and / or aluminum sulfate. Specifically, the first aluminum source can be sodium aluminate, the second aluminum source can be a mixture of sodium aluminate and aluminum sulfate, and the third aluminum source can be sodium aluminate.
[0092] In one embodiment of the present disclosure, the first alkali source includes one or more of sodium aluminate, sodium hydroxide and potassium hydroxide; preferably sodium aluminate.
[0093] In one embodiment of the present disclosure, the conditions of the second crystallization treatment include: time of 10-30 hours and temperature of 170-200°C.
[0094] In one embodiment of the present disclosure, the method further includes: filtering, washing, ammonium exchange, second drying and second calcination of the primary product obtained by the second crystallization treatment, and the above operations are conventional in the art and are not specifically required. For example, the conditions for the second drying include: a temperature of 90-120°C and a time of 4-30h; preferably, a temperature of 110-120°C and a time of 10-16h. The conditions for the second calcination include: a temperature of 400-800°C and a time of 0.5-8h; preferably, a temperature of 450-600°C and a time of 3-5h.
[0095] The reagents used in the following examples and comparative examples are all commercially available.
[0096] Examples 1-5 are used to illustrate the ZSM-5 / Y composite molecular sieve and its preparation method of the present application.
[0097] Example 1
[0098] The ZSM-5 / Y composite molecular sieve was prepared according to the following steps.
[0099] 1) The first alkali source in terms of alkali metal oxide and the first alkali source in terms of Al 2 O 3 The first aluminum source and SiO 2 The first silicon source is stirred evenly in a molar ratio of 16.5:1:15, and aged at room temperature for 24 hours to prepare a NaY structure directing agent;
[0100] 2) Al 2 O 3 The second aluminum source is Na 2 O-based NaOH, SiO 2 The second silicon source and deionized water are mixed in a molar ratio of 1:2.7:8.7:210, and then a NaY structure directing agent is added to prepare a NaY molecular sieve mother solution, with a pH of 11.5-12.5;
[0101] Wherein, based on the total weight of NaY molecular sieve mother liquor, Al 2 O 3 The amount of NaY structure directing agent added is 5 wt %;
[0102] 3) Al 2 O 3 The third aluminum source is Na 2 O-based NaOH, SiO 2 The third silicon source and deionized water are mixed in a molar ratio of 1:3.27:32.7:350, and seed crystals are added thereto to prepare a ZSM-5 molecular sieve mother solution;
[0103] Wherein, based on the total weight of ZSM-5 molecular sieve mother liquor, SiO 2 The amount of seed crystals added is 10% by weight;
[0104] 4) The ZSM-5 molecular sieve mother liquor prepared in step 3) is transferred to a stainless steel kettle and subjected to a second crystallization treatment for 20 hours at a temperature of 180° C., followed by filtration, washing to a pH of 7-8, ammonium exchange, and a second drying treatment at 120° C. for 12 hours; a second calcination treatment at 550° C. in an air atmosphere for 4 hours to obtain a ZSM-5 molecular sieve having a silicon-to-aluminum ratio of 25;
[0105] 5) adding the ZSM-5 molecular sieve to the NaY molecular sieve mother solution of step 2), stirring for 3 hours, and mixing evenly to obtain a mixed material;
[0106] The mass ratio of ZSM-5 molecular sieve to NaY molecular sieve mother liquor is 0.078:1, the mass of ZSM-5 molecular sieve is 7 g, and the mass of NaY molecular sieve mother liquor is 90 g.
[0107] 6) The mixture of step 5) is transferred to a hydrothermal stainless steel autoclave for a first crystallization treatment for 30 hours at 97°C, followed by filtration, washing to pH = 7-8, ammonium exchange, and a first drying treatment at 120°C for 12 hours; and a first calcination treatment at 550°C in an air atmosphere for 6 hours to obtain ZSM-5 / Y composite molecular sieve A1.
[0108] The pore structure parameters of ZSM-5 / Y composite molecular sieve A1 are listed in Table 1. Figure 2 This is a scanning electron microscope image of ZSM-5 / Y composite molecular sieve A1.
[0109] Wherein, the first alkali source is sodium aluminate (Na 2 O: 297.8 g / L, Al 2 O 3 : 42.2g / L);
[0110] The first aluminum source is sodium aluminate (Na 2 O: 297.8 g / L, Al 2 O 3 : 42.2g / L);
[0111] The first silicon source is water glass (SiO 2 : 251.6g / L);
[0112] The second aluminum source is sodium aluminate (Na 2 O: 154.6 g / L, Al 2 O 3 : 100.6 g / L) and aluminum sulfate;
[0113] The second silicon source is water glass (SiO 2 : 251.6g / L);
[0114] The third aluminum source is sodium aluminate (Na 2 O: 154.6 g / L, Al 2 O 3 : 100.6g / L);
[0115] The third silicon source is silica gel (SiO 2 : solid content is 88wt%);
[0116] The seed crystals are ZSM-5 molecular sieve seed crystals with a silicon-aluminum ratio of 25 produced by an industrial amine-free process.
[0117] Example 2
[0118] The ZSM-5 / Y composite molecular sieve was prepared by the method of Example 1, except that the ZSM-5 molecular sieve obtained in step 4) was mixed with a NaOH solution to obtain an alkali-treated ZSM-5 molecular sieve; wherein the concentration of the NaOH solution was 0.5 mol / L, and the NaOH and SiO 2 The molar ratio of the ZSM-5 molecular sieve is 0.1:1, the alkali treatment time is 4h, and the alkali treatment temperature is 120°C. The prepared ZSM-5 / Y composite molecular sieve is recorded as A2, and the pore structure parameters of the ZSM-5 / Y composite molecular sieve A2 are tested and listed in Table 1. Figure 4 This is a scanning electron microscope image of ZSM-5 / Y composite molecular sieve A2.
[0119] Example 3
[0120] The ZSM-5 / Y composite molecular sieve was prepared by the same method as in Example 2, except that the mass of the ZSM-5 molecular sieve was 15 g, the NaY molecular sieve mother liquor was 90 g, the mass ratio of the ZSM-5 molecular sieve to the NaY molecular sieve mother liquor was 0.167:1, and the prepared ZSM-5 / Y composite molecular sieve was recorded as A3. The pore structure parameter tests of the ZSM-5 / Y composite molecular sieve A3 are listed in Table 1. Figure 3 It is the X-ray diffraction pattern of ZSM-5 / Y composite molecular sieves A2 and A3. Figure 5 This is a scanning electron microscope image of ZSM-5 / Y composite molecular sieve A3. Figure 6 These are the nitrogen adsorption and desorption curves of ZSM-5 / Y composite molecular sieves A2 and A3.
[0121] Example 4
[0122] The ZSM-5 / Y composite molecular sieve was prepared by the same method as in Example 2, except that the ZSM-5 molecular sieve obtained in step 4) was mixed with a TEAOH solution to obtain an alkali-treated ZSM-5 molecular sieve; wherein the concentration of the TEAOH solution was 0.5 mol / L, and the TEAOH and SiO 2 The molar ratio of the ZSM-5 molecular sieve is 0.1: 1. The prepared ZSM-5 / Y composite molecular sieve is recorded as A4, and the pore structure parameters of the ZSM-5 / Y composite molecular sieve A4 are listed in Table 1. Figure 8 This is a scanning electron microscope image of ZSM-5 / Y composite molecular sieve A4.
[0123] Example 5
[0124] The ZSM-5 / Y composite molecular sieve was prepared by the same method as in Example 4, except that the mass of the ZSM-5 molecular sieve was 15 g, the NaY molecular sieve mother liquor was 90 g, the mass ratio of the ZSM-5 molecular sieve to the NaY molecular sieve mother liquor was 0.167:1, and the prepared ZSM-5 / Y composite molecular sieve was recorded as A5. The pore structure parameter tests of the ZSM-5 / Y composite molecular sieve A5 are listed in Table 1. Figure 7 It is the X-ray diffraction spectrum of ZSM-5 / Y composite molecular sieves A4 and A5. Fig. 9 This is a scanning electron microscope image of ZSM-5 / Y composite molecular sieve A5.
[0125] Comparative Example 1
[0126] The ZSM-5 / Y composite molecular sieve was prepared by the same method as in Example 1, except that the mass ratio of the ZSM-5 molecular sieve to the NaY molecular sieve mother liquor was 1.1:1, the mass of the ZSM-5 molecular sieve was 99 g, and the mass of the NaY molecular sieve mother liquor was 90 g. The prepared ZSM-5 / Y composite molecular sieve was recorded as D1, and the pore structure parameters of the ZSM-5 / Y composite molecular sieve D1 were tested and listed in Table 1. Fig.10 This is a scanning electron microscope image of ZSM-5 / Y composite molecular sieve D1.
[0127] Comparative Example 2
[0128] The ZSM-5 / Y composite molecular sieve was prepared by the same method as in Example 2, except that the mass ratio of the ZSM-5 molecular sieve to the NaY molecular sieve mother liquor was 1.1:1, the molecular sieve mass was 99 g, and the NaY molecular sieve mother liquor was 90 g. The prepared ZSM-5 / Y composite molecular sieve was recorded as D2, and the pore structure parameters of the ZSM-5 / Y composite molecular sieve D2 were tested and listed in Table 1. Figure 1 It is the X-ray diffraction pattern of ZSM-5 / Y composite molecular sieves A1, D1 and D2.
[0129] Comparative Example 3
[0130] 1) The first alkali source in terms of alkali metal oxide and the first alkali source in terms of Al 2 O 3 The first aluminum source and SiO 2 The first silicon source is stirred evenly in a molar ratio of 16.5:1:15, and aged at room temperature for 24 hours to prepare a NaY structure directing agent;
[0131] 2) Al 2 O 3 The second aluminum source is Na 2 O-based NaOH, SiO 2The second silicon source and deionized water are mixed in a molar ratio of 1:2.7:8.7:210, and then NaY structure directing agent is added to prepare NaY molecular sieve mother solution, pH = 11.5-12.5; wherein, according to weight percentage, Al 2 O 3 The amount of NaY structure directing agent added is 5 wt %;
[0132] 3) transferring the NaY molecular sieve mother liquor obtained in step 2) to a hydrothermal stainless steel kettle, crystallizing at 97° C. for 30 h, filtering, washing to pH=7-8, ammonium exchange, drying at 120° C. for 12 h, and then calcining at 600° C. for 6 h to obtain a NaY molecular sieve;
[0133] 4) Al 2 O 3 The third aluminum source is Na 2 O-based NaOH, SiO 2 The third silicon source and deionized water are mixed in a molar ratio of 1:3.27:32.7:350, and seed crystals are added thereto to prepare a ZSM-5 molecular sieve mother liquid; wherein, based on the total weight of the ZSM-5 molecular sieve mother liquid, SiO 2 The amount of seed crystals added is 10% by weight;
[0134] 5) The ZSM-5 molecular sieve mother liquor obtained in step 4) was transferred to a stainless steel kettle, crystallized at 180° C. for 20 h, filtered, ammonium exchanged, dried at 120° C. for 12 h, and then calcined at 550° C. for 4 h to obtain a ZSM-5 molecular sieve;
[0135] 6) The NaY molecular sieve and the ZSM-5 molecular sieve obtained in step 3) and 5) are mechanically mixed at a mass ratio of 1:1 to obtain a mixed molecular sieve, which is recorded as D3. The pore structure parameters of the mixed molecular sieve D3 are listed in Table 1.
[0136] Wherein, the first alkali source is sodium aluminate (Na 2 O: 297.8 g / L, Al 2 O 3 : 42.2g / L);
[0137] The first aluminum source is sodium aluminate (Na 2 O: 297.8 g / L, Al 2 O 3 : 42.2g / L);
[0138] The first silicon source is water glass (SiO 2 : 251.6g / L);
[0139] The second aluminum source is sodium aluminate (Na 2 O: 154.6 g / L, Al 2 O 3 : 100.6 g / L) and aluminum sulfate;
[0140] The second silicon source is water glass (SiO 2 : 251.6g / L);
[0141] The third aluminum source is sodium aluminate (Na 2 O: 154.6 g / L, Al 2 O 3 : 100.6g / L);
[0142] The third silicon source is silica gel (solid content is 88 wt %);
[0143] The seed crystals are ZSM-5 molecular sieve seed crystals with a silicon-aluminum ratio of 25 synthesized by an industrial amine-free method.
[0144] The X-ray diffraction spectra were measured on a Rigaku TTR-3 powder X-ray diffractometer with the following instrument parameters: copper target (tube voltage 40 kV, tube current 250 mA), scintillation counter, step width 0.02°, and scanning rate 0.4° / min.
[0145] The nitrogen adsorption-desorption curves were measured using the AS-3 and AS-6 static nitrogen adsorption instruments produced by Quanta Chrome Instruments. Instrument parameters: The sample was placed in the sample handling system and vacuumed to 1.33×10 -2 Pa, keep the temperature and pressure for 4 hours, and purify the sample. Test the purified sample at different pressure ratios P / P at a liquid nitrogen temperature of -196°C. 0 The adsorption and desorption amounts under the conditions were calculated to obtain the nitrogen adsorption-desorption isotherm curve, and then the specific surface area was calculated using the two-parameter BET formula. The linear part P / P in the adsorption branch of the nitrogen adsorption-desorption curve was selected. 0 The isothermal adsorption data of 0-0.25 was used to calculate the desorption branch data using the BJH method to obtain the pore size distribution data of the sample. The total pore volume and micropore volume were analyzed and calculated using the t-plot method. The mesoporous volume is the total pore volume minus the micropore volume.
[0146] The scanning electron microscope was a Hitachi S4800 high-resolution cold field emission scanning electron microscope. After the sample was dried, gold was sprayed by vacuum evaporation to increase the conductivity and contrast effect, with an acceleration voltage of 20 kV.
[0147] Table 1
[0148]
[0149]
[0150] The composite molecular sieve prepared in the embodiment and the comparative example was used as a catalyst in the catalytic cracking reaction of heavy oil to carry out the catalytic cracking reaction. The specific method is as follows: The effect of the molecular sieve on the yield and conversion rate of light olefins in the catalytic cracking of heavy oil was evaluated by a pure hydrocarbon micro-reaction. The reaction was carried out in a fixed bed reactor, the carrier gas was nitrogen, the flow rate was 30 mL / min, the reaction temperature was 530°C, the regeneration temperature was 600°C, and the weight space velocity was 7h -1 The molecular sieve was sieved into 20-40 mesh particles after tableting, the filling amount was 2g, the agent-oil ratio was 1:0.78, and the samples were taken for analysis after 900s of reaction, and the material balance calculation was performed. The product distribution is shown in Tables 2 and 3.
[0151] The following formula is used to calculate the micro-reaction conversion rate X of the raw material and the yield Yi of the product:
[0152] X = 100% × weight of raw oil consumed in the reaction / total weight of incoming oil;
[0153] Yi = weight of component i in the product / weight of raw oil consumed in the reaction × 100%;
[0154] Among them, the weight of the raw oil consumed in the reaction = the total weight of the input oil - the weight of the raw oil remaining in the reaction.
[0155] Test Example 1-8
[0156] The ZSM-5 / Y composite molecular sieves prepared in Examples 1-5 and Comparative Examples 1-2 and the mixed molecular sieve prepared in Comparative Example 3 were evaluated in a fixed bed microreactor. The raw material was refinery hydrogenated VGO, and its performance parameters are listed in Table 4. The reaction temperature was 530°C, the oil feed time was 70s, the oil feed amount was 1.56g, the molecular sieve loading amount was 2g, and the evaluation results were shown in Table 2.
[0157] Table 2
[0158]
[0159]
[0160] Examples 9-16
[0161] The ZSM-5 / Y composite molecular sieves prepared in Examples 1-5 and Comparative Examples 1-2 and the mixed molecular sieve prepared in Comparative Example 3 were evaluated in a fixed bed microreactor. The raw material was atmospheric residue oil, and its performance parameters are listed in Table 4. The reaction temperature was 530°C, the oil feed time was 70s, the oil feed amount was 1.56g, the molecular sieve loading amount was 2g, and the evaluation results were shown in Table 3.
[0162] Table 3
[0163]
[0164] Table 4
[0165]
[0166]
[0167] According to the data in Table 1-4, relative to Comparative Examples 1-3, the molecular sieve prepared by limiting the mass ratio of ZSM-5 molecular sieve to NaY molecular sieve mother liquor in the present application has a special pore structure, and its specific surface area, total pore volume, and total volume of mesopores are significantly higher than those in Comparative Examples 1-3, indicating that the composite molecular sieve of the present application uses ZSM-5 as the core and Y as the shell, and the coating of the ZSM-5 molecular sieve is more uniform. When it is used for the catalytic cracking reaction of heavy oil, the raw material conversion rate is improved, the yield of ethylene, propylene and butene is high, the low-carbon selectivity is high, the coke yield is low, and the anti-carbon deposition performance is good. And according to the scanning electron microscope image, it can be seen that in the ZSM-5 / Y composite molecular sieve of the present application, the Y molecular sieve is uniformly attached to the surface of the ZSM-5 molecular sieve, and the coating forms a core-shell structure.
[0168] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.
[0169] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.
[0170] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.
Claims
1. A method for catalytic cracking reaction, characterized in that: The method includes: Contacting the ZSM-5 / Y composite molecular sieve with the raw material to carry out the catalytic cracking reaction; Wherein, the ZSM-5 / Y composite molecular sieve comprises ZSM-5 molecular sieve particles and Y molecular sieve particles, and the Y molecular sieve particles are coated on the surface of the ZSM-5 molecular sieve particles; The specific surface area of the ZSM-5 / Y composite molecular sieve is 350-740m 2 / g, with a total pore volume of 0.15-0.38cm 3 / g, the pore volume of micropores is 0.14-0.34cm 3 / g, and the pore volume of the mesopores is 0.03-0.09cm 3 / g; The raw material is selected from one or more of hydrogenated diesel, hydrogenated naphtha, atmospheric residue, hydrogenated VGO and heavy naphtha; In the ZSM-5 / Y composite molecular sieve, the mass ratio of the ZSM-5 molecular sieve particles to the Y molecular sieve particles is 0.1-3.
2. The method according to claim 1, wherein: In the catalytic cracking reaction, the reaction temperature is 500-580° C., and the mass ratio of the ZSM-5 / Y composite molecular sieve to the feed oil of the raw material is 1:(0.5-3).
3. The method according to claim 1, wherein: The reactor for the catalytic cracking reaction is selected from one or more of a fixed bed reactor, a riser reactor and a fluidized bed reactor.
4. The method according to claim 1, wherein: The reactor for the catalytic cracking reaction is selected from a fixed bed microreactor.
5. The method according to claim 1, wherein: The specific surface area of the ZSM-5 / Y composite molecular sieve is 490-680m 2 / g, with a total pore volume of 0.25-0.38cm 3 / g, the pore volume of micropores is 0.20-0.27cm 3 / g, and the pore volume of the mesopores is 0.03-0.09cm 3 / g.
6. The method according to claim 1, wherein: The method also includes preparing the ZSM-5 / Y composite molecular sieve by the following steps: Mixing the ZSM-5 molecular sieve and the NaY molecular sieve mother liquor to obtain a mixed material, and performing a first crystallization treatment on the mixed material; The mass ratio of the ZSM-5 molecular sieve to the NaY molecular sieve mother liquor is (0.01-0.5):1; the conditions of the first crystallization treatment include: a temperature of 90-120° C. and a time of 10-40 hours.
7. The method according to claim 6, wherein: The method further includes: Before mixing the ZSM-5 molecular sieve with the NaY molecular sieve mother liquor, the ZSM-5 molecular sieve is subjected to an alkali treatment, wherein the alkali treatment comprises: contacting the ZSM-5 molecular sieve with an alkali solution; the alkali treatment temperature is 120-200° C., and the time is 1-5 hours; The concentration of the alkaline solution is 0.2-0.8 mol / L, and the alkali in the alkaline solution includes one or more of NaOH, TEAOH and TPAOH; the molar ratio of the alkali to the ZSM-5 molecular sieve calculated as SiO2 is (0.1-0.5):
1.
8. The method according to claim 6, wherein: The method further includes filtering, washing, ammonium exchanging, first drying and first calcining the pre-product obtained by the first crystallization treatment.
9. The method according to claim 8, wherein: The first drying conditions include: temperature of 90-120°C and time of 4-30h; The first calcination is carried out in an air atmosphere and / or a water vapor atmosphere, the temperature of the first calcination is 400-800° C., and the time is 0.5-8 hours.
10. The method according to claim 6, wherein: The method also includes preparing the NaY molecular sieve mother solution by the following steps: S1, mixing a first alkali source, a first aluminum source and a first silicon source and aging the mixture to prepare a NaY structure directing agent; S2, mixing the NaY structure directing agent with NaOH, a second aluminum source, a second silicon source and deionized water to obtain the NaY molecular sieve mother solution; Wherein, the molar ratio of the first alkali source calculated as alkali metal oxide, the first aluminum source calculated as Al2O3 and the first silicon source calculated as SiO2 is (10-18):1:(10-18); The molar ratio of the second aluminum source calculated as Al2O3, the NaOH calculated as Na2O, the second silicon source calculated as SiO2 and the deionized water is 1:(1-3):(3-9):(150-240). The amount of the NaY structure directing agent added in terms of Al2O3 is 1-10 wt % in terms of weight percentage, based on the total weight of the NaY molecular sieve mother liquor.
11. The method according to claim 10, wherein: The first silicon source and the second silicon source independently include one or more of silica gel, silicon dioxide and silicate; The first aluminum source and the second aluminum source independently include one or more of sodium aluminate, aluminum hydroxide, pseudo-boehmite, aluminum sulfate, aluminum alcoholate and aluminum oxide; The first alkali source includes one or more of sodium aluminate, sodium hydroxide and potassium hydroxide.
12. The method according to claim 10, wherein: The first silicon source and / or the second silicon source includes white carbon black.
13. The method according to claim 10, wherein: The aging time is 8-30h.
14. The method according to claim 10, wherein: The method also includes preparing the ZSM-5 molecular sieve by the following steps: S1, mixing NaOH, a third silicon source, a third aluminum source, a seed crystal and deionized water to obtain a ZSM-5 molecular sieve mother liquor, wherein the ZSM-5 molecular sieve mother liquor does not contain a template agent; S2, performing a second crystallization treatment on the ZSM-5 molecular sieve mother liquor; The conditions of the second crystallization treatment include: time of 10-30h, temperature of 170-200°C; Among them, the molar ratio of the third aluminum source calculated as Al2O3, the NaOH calculated as Na2O, the third silicon source calculated as SiO2 and deionized water is 1:(0.2-11):(20-50):(230-1200), and the amount of the seed crystal added in terms of SiO2 is 5-30 weight % based on the total weight of the ZSM-5 molecular sieve mother liquor and calculated in weight percentage.
15. The method according to claim 14, wherein: The third silicon source includes one or more of silica gel, silicon dioxide and silicate; The third aluminum source includes one or more of sodium aluminate, pseudo-boehmite, aluminum alcoholate, aluminum oxide, aluminum hydroxide and aluminum sulfate; The seed crystals include one or more ZSM-5 molecular sieve seed crystals with a silicon-aluminum ratio of 20-50.
16. The method according to claim 14, wherein: The third silicon source includes white carbon black.
17. The method according to claim 14 or 15, wherein: The method further comprises: filtering, washing, ammonium exchanging, second drying and second roasting the primary product obtained by the second crystallization treatment.
18. The method according to claim 17, wherein: The second drying conditions include: temperature of 90-120°C and time of 4-30h; The second calcination conditions include: temperature of 400-800° C. and time of 0.5-8 h.