Lanthanum sulfate catalyst for preparing olefin through cracking and preparation method of lanthanum sulfate catalyst

Abstract

The invention relates to a high propylene / ethylene ratio lanthanum sulfate cracking olefin preparation catalyst and a use method thereof. The method comprises mixing sulfur source and lanthanum source loaded particles A and oxidant loaded particles B into a catalyst for use. The catalyst is used in a circulating fluidized bed reactor, and sulfur and oxygen in a lanthanum sulfate crystal phase formed on particles A are used for activating hydrocarbon molecules in a reaction stage, so that the aim of improving the yield of propylene is fulfilled; and in the regeneration stage, oxidizing agent particles on the particles B are used for carrying out oxidation reaction, and the lanthanum sulfate crystal phase is recovered, so that continuous circular reaction regeneration is realized. The catalyst can be independently used as a catalyst, and can also be added into other catalysts to be used as an auxiliary agent.

Description

Technical Field

[0001] This application relates to a catalyst for the catalytic cracking of hydrocarbons to prepare olefins, specifically, to a lanthanum sulfate catalyst that can improve the propylene / ethylene ratio and its preparation method. Background Technology

[0002] Low-carbon olefins are one of the main products of the petrochemical industry, primarily used to produce polymers (polyethylene and polypropylene). Currently, domestic ethylene and propylene production is insufficient, with the propylene / ethylene demand ratio showing an upward trend while the output ratio is declining. With the development of the chemical industry, the demand for low-carbon olefins is growing rapidly, and their production has become an important indicator of economic development. Low-carbon olefins are mainly obtained through the thermal cracking or catalytic cracking of hydrocarbons. Thermal cracking is the primary technology for producing low-carbon olefins, but it involves high reaction temperatures and large carbon dioxide emissions. Catalytic cracking, on the other hand, involves lower reaction temperatures and higher olefin yields, making it the most promising technology for development and application in recent years. Most cracking catalysts fall into two categories: molecular sieve catalysts and metal oxide catalysts.

[0003] Molecular sieve catalysts possess unique physicochemical properties, and most of them are modified molecular sieves in order to obtain high olefin yields.

[0004] Yoshimura et al. developed a novel P-La-ZSM-5 catalyst based on ZSM-5 molecular sieves and found that the propylene / ethylene ratio of naphtha catalytic cracking was close to 0.7 in a nitrogen atmosphere at 650℃. This method uses nitrogen as a dilution gas, which is more conducive to the formation of olefins. At the same time, although the olefin yield is high, ethylene is the main product, and the propylene / ethylene ratio is low. Ji Dong et al. (Study on the catalytic cracking of C4 alkanes to ethylene and propylene by high-silica molecular sieve ZSM-23, Molecular Catalysis, 2007, 21(3): 193-200) developed high-silica molecular sieve ZSM-23 for catalytic cracking of alkanes. The results showed that at a temperature of 650℃, the ethylene yield of ZSM-23 molecular sieve was 43.8%, the propylene yield was 12.1%, the ethylene-propylene yield reached 56%, and the butane conversion rate reached 88.9%. This technology has a high ethylene and propylene yield, but the molecular sieve synthesis cost is high, the process is complex, the propylene yield is low, and the propylene / ethylene ratio is only 0.28.

[0005] Lu et al. studied the isobutane catalytic cracking performance of Fe-modified HZSM-5. At 625℃, the Fe / HZSM-5 selectivity ratio for propylene and ethylene was 1.32. However, in this reaction, the feedstock was a mixture of isobutane and nitrogen, with isobutane accounting for only 5% of the total gas flow. This diluted gas favored olefin formation; although the total olefin selectivity was high, the overall propylene / ethylene ratio remained at 1.32.

[0006] Qureshi et al. used P-modified MFI molecular sieves with a silica-to-alumina ratio of 280 for n-pentane cracking at 650 °C, with a feed of 2 ml / min n-pentane and 20 ml / min N2 as dilution gas, achieving a propylene / ethylene ratio of 1.3 for light olefins. However, molecular sieve synthesis is costly and requires nitrogen as a dilution gas, resulting in a low propylene / ethylene ratio.

[0007] Wang et al. found that the ZSM-5 catalyst treated with NaHCO3 at 590℃ exhibited the best n-pentane conversion and olefin selectivity, with a propylene / ethylene ratio of only 0.95.

[0008] Although molecular sieve catalysts can achieve high olefin yields, the synthesis cost of molecular sieves is high, the subsequent modification process is complex, and the improvement of the propylene / ethylene ratio is limited.

[0009] Metal oxide catalysts have begun industrial-scale trials in the production of low-carbon olefins. A potassium-vanadium catalyst supported on ceramics, jointly developed by the Russian Institute of Organic Synthesis and the Moscow Gubokin Oil and Gas Research Institute, has undergone pilot-scale (40–70 kg / h) and semi-industrial-scale (2000 kg / h) experiments. In the catalytic cracking of diesel fuel (boiling range 235–350 °C) at 770 °C, the ethylene yield reached 30.7%, and the propylene yield reached 14.4%. This technology achieves a relatively high reaction temperature of 770 °C and a propylene / ethylene yield ratio of 0.47.

[0010] Phillips Petroleum Corporation of the United States has developed a metal oxide catalyst for the cracking of low-carbon alkanes to olefins. The catalyst uses MnO or Fe2O3 as the main active component and MgO as the support (Li Xiaoming, Song Furong. Technological progress in catalytic cracking to olefins [J]. Petrochemical Industry, 2002, 31(7):569-573.). The catalyst is suitable for the catalytic cracking of propane and butane. In addition to single MnO and Fe2O3, the main active components also include bimetallic La2O3-Fe2O3 and Nb2O5-Fe2O3. The promoters are oxides of calcium, strontium, barium, tin, antimony, silicon, aluminum, titanium, and chromium. The role of the promoters is to extend the catalyst life and improve the selectivity of ethylene. Except for calcium, strontium, barium, tin, and antimony, all of the above promoters can be used in iron / magnesium and manganese / magnesium catalysts. Only chromium can be used as a promoter for lanthanide and niobium-based catalysts. The feedstock is n-butane, 700℃, water-oil ratio is 1, and space velocity is 4.2h. -1 When using a 3% Ca-5% MnO-MgO catalyst, the n-butane conversion rate is 65%, and the selectivity for ethylene and propylene can reach 35% and 22%, respectively. After adding hydrogen sulfide or hydrogen sulfide precursor, the n-butane conversion rate is 68%, and the selectivity for ethylene and propylene can reach 19% and 38%, respectively, with a propylene / ethylene ratio of 2. However, a large amount of water vapor was added as a dilution gas in the experiment.

[0011] The German Institute for Organic Chemistry has developed a TCSC catalyst. This catalyst possesses the following characteristics: excellent pyrolysis activity, coke gasification activity, high-temperature stability, hydrothermal stability, long lifespan, and applicability to various types of feedstocks. Studies have found that the catalyst exhibits superior performance in all aspects when the CaO / Al₂O₃ calcium-aluminum ratio is 0.43. When used for pyrolysis of AGO, the total ethylene-propylene yield can reach 38.4%, with a propylene-ethylene ratio of 0.43.

[0012] Existing catalysts developed for the catalytic cracking to produce propylene and ethylene have low propylene content in their products, meaning the propylene / ethylene ratio needs to be further improved. Summary of the Invention

[0013] One object of this application is to provide a catalyst for catalytic cracking of hydrocarbons, which can increase the propylene / ethylene ratio.

[0014] One object of this application is to provide a catalyst for catalytic cracking of hydrocarbons, which is continuously recycled in a system for catalytic cracking of hydrocarbons to produce propylene and ethylene, i.e., the catalyst has a long service life.

[0015] Another objective of this application is to use the catalyst of this application to catalytically crack hydrocarbons to produce propylene and ethylene, thereby increasing the propylene content in the product, specifically by increasing the propylene / ethylene ratio.

[0016] A catalyst for catalytic cracking of hydrocarbons includes lanthanum sulfate and a metal oxide; said metal oxide includes cerium oxide, oxide of Group VIII metal, oxide of Group VB metal, or oxide of Group VIIB metal.

[0017] The hydrocarbons mentioned include one or more of the following: alkanes, alkenes, wax oils, naphtha, gasoline, diesel, crude oil, or residual oil.

[0018] The catalyst of this application is used in a reaction system for the catalytic cracking of hydrocarbons to produce propylene and ethylene. The resulting product has a high propylene content, specifically a high propylene / ethylene ratio.

[0019] A reaction method for catalytic cracking of hydrocarbons to produce propylene and ethylene, wherein the hydrocarbons are cracked at a temperature controlled at 500-700℃ under the action of the above-mentioned catalyst, and the products obtained include propylene and ethylene.

[0020] The resulting ratio of propylene to ethylene (molar ratio) can be as high as 2.0 or more. Attached Figure Description

[0021] Figure 1This is the XRD pattern of the catalyst prepared in Example 3. Detailed Implementation

[0022] The following describes in further detail a method for preparing propylene and ethylene from hydrocarbons by catalytic cracking, and the catalyst used herein. This does not limit the scope of protection of this application, which is defined by the claims. Certain specific details disclosed provide a comprehensive understanding of the various disclosed embodiments. However, those skilled in the art will recognize that embodiments can be implemented using other materials, etc., without employing one or more of these specific details.

[0023] Unless the context otherwise requires, the terms “comprising” and “including” in the specification and claims shall be understood as open-ended and inclusive, meaning “including, but not limited to”.

[0024] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0025] In this specification, the numerical range indicated by "above" or "below" refers to the numerical range that includes the stated number.

[0026] The terms "implementation," "an implementation / preferred implementation," "another implementation / preferred implementation," or "certain implementations" used in this specification refer to specific elements described in relation to the implementation (e.g., specific features, structures, or characteristics) included in at least one implementation. Therefore, "implementation," "an implementation," "another implementation," or "certain implementations" do not necessarily all refer to the same implementation. Furthermore, specific features, structures, or characteristics can be combined in any way within one or more implementations. Each feature disclosed in this specification can be replaced by any alternative feature that provides the same, equivalent, or similar purpose. Therefore, unless otherwise specified, the disclosed features are merely general examples of equivalent or similar features.

[0027] Unless otherwise specified, experimental methods in the following examples are generally performed under standard conditions or as recommended by the manufacturer. Unless otherwise stated, all percentages, ratios, proportions, or parts are by weight.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as are familiar to one skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be used in the methods of this application. The preferred embodiments and materials described herein are for illustrative purposes only.

[0029] Definition: "Space velocity" is the amount of gas processed per unit volume of catalyst per unit time, expressed in m³ / s. 3 / (m 3 Catalyst (h) can be simplified to h -1 .

[0030] On the one hand, catalysts used for catalytic cracking of hydrocarbons include lanthanum sulfate and metal oxides; the metal oxides include cerium oxides, oxides of Group VIII metals, oxides of Group VB metals, or oxides of Group VIIB metals.

[0031] The catalyst in this application includes lanthanum sulfate and metal oxides of specific substances. In the catalytic cracking reaction system of hydrocarbons, during the reaction, oxygen and sulfur in the lanthanum sulfate crystal phase of the catalyst activate hydrocarbon molecules, increasing the propylene / ethylene ratio in olefins. After deactivation, the catalyst undergoes carbonization, where certain metal oxide particles undergo redox reactions to replenish sulfur and restore the lanthanum sulfate structure, allowing for reuse.

[0032] In some embodiments, the metal oxide includes one or more of cerium oxide, vanadium oxide, iron oxide, and manganese oxide.

[0033] For example, one or more of cerium oxide, vanadium pentoxide, ferric oxide, or manganese dioxide.

[0034] During the reaction, the lanthanum sulfate crystal phase structure is destroyed. These metal oxides can effectively regenerate the catalyst after the reaction into the lanthanum sulfate crystal phase structure, allowing it to continue to play a catalytic role.

[0035] In some embodiments, the mass ratio of lanthanum sulfate to metal oxide in the catalyst is (5-100):1.

[0036] The metal oxides in the catalyst are within the above-mentioned range. In the catalytic cracking of hydrocarbons to produce propylene and ethylene, the catalyst has excellent catalytic performance. On the other hand, during the regeneration of the deactivated catalyst, the metal oxides in the catalyst of this application promote the conversion of sulfur dioxide formed after the combustion of sulfides into sulfur trioxide. The sulfur trioxide then combines with the components on the deactivated catalyst to restore the lanthanum sulfate crystal phase.

[0037] In some embodiments, lanthanum sulfate is loaded onto a support, and the proportion of lanthanum sulfate to the total mass of the support and lanthanum sulfate is 2-20 wt%.

[0038] Catalysts include lanthanum sulfate, metal oxides, and supports.

[0039] Optionally, the metal oxide is loaded onto the support. The metal oxide accounts for 0.1-10 wt% of the total mass of the support and the metal oxide.

[0040] The carrier may include one or a combination of two or more of amorphous silica, chromatographic silica, magnesium aluminum spinel, zinc aluminum spinel or magnesium aluminum hydrotalcite.

[0041] Alternatively, the catalyst support may be one of amorphous silica, chromatographic silica, magnesium aluminum spinel, zinc aluminum spinel, or magnesium aluminum hydrotalcite.

[0042] In some embodiments, the metal oxide in the catalyst is preferably cerium oxide, and the mass ratio of lanthanum sulfate to the metal oxide is (40-60):1. This results in a better catalytic effect and a higher propylene yield.

[0043] The catalyst described above can be obtained by mixing lanthanum sulfate with a metal oxide, or by mixing lanthanum sulfate with a support for loaded metal oxides.

[0044] The preparation method of the above catalyst includes: mixing lanthanum source and sulfur source into a mixed solution, impregnating the mixed solution onto a support, and obtaining lanthanum sulfate particles A after drying and calcination at a calcination temperature of 600-800℃;

[0045] A soluble metal salt solution is impregnated onto a carrier, and after drying and calcination, oxidant particles B are obtained. The calcination temperature is 600-800℃. The metals include cerium, Group VIII metals, Group VB metals, or Group VIIB metals.

[0046] Lanthanum sulfate particles A and oxidant particles B are mechanically mixed to obtain a lanthanum sulfate catalyst.

[0047] Alternatively, the preparation method of the above catalyst includes: mixing a lanthanum source and a sulfur source into a mixed solution, impregnating the mixed solution onto a support, and obtaining lanthanum sulfate particles A after drying and calcination at a calcination temperature of 600-800℃;

[0048] Lanthanum sulfate particles A are mechanically mixed with metal oxides to obtain a lanthanum sulfate catalyst, wherein the metals include cerium, Group VIII metals, Group VB metals, or Group VIIB metals.

[0049] It is also feasible to directly mix lanthanum sulfate particles A with metal oxides in the above proportions. However, given the strength requirements of the catalyst during use, the preparation method described in this application is preferred.

[0050] In some embodiments, the molar ratio of La to S in the mixed solution is 2:(3-5).

[0051] Within this range, particles with a lanthanum sulfate crystal phase structure can be obtained after drying and calcination.

[0052] In the mixed solution, the solute concentration of lanthanum sulfate is 0.5-5 wt%. Within this range, the sulfur source and lanthanum source can be loaded onto the support more uniformly. That is, the concentration of lanthanum sulfate obtained after the reaction of the lanthanum source and sulfur source in the mixed solution.

[0053] The lanthanum source includes, but is not limited to, one or more combinations of lanthanum nitrate, lanthanum oxide, or lanthanum carbonate; the sulfur source includes, but is not limited to, one or more combinations of sulfuric acid, ammonium sulfate, or ammonium bisulfate.

[0054] Soluble metal salts can be soluble nitrates, such as cerium nitrate and vanadium nitrate.

[0055] The mass concentration of the soluble metal salt solution is 0.1-10 wt%.

[0056] In the catalyst preparation steps of this application, the drying temperature is controlled at 90-110℃. Moisture content only needs to be kept within a certain range, and the drying time can be adjusted according to actual requirements.

[0057] In this application, the drying time is between 1 hour and 5 hours.

[0058] In some embodiments, the calcination time during the preparation of lanthanum sulfate particles A is 1-12 hours.

[0059] If the calcination time is too short, the calcination will be insufficient; if the time is too long, the catalyst particles will easily aggregate and become larger. A calcination time controlled between 1 and 12 hours is ideal for the formation of the lanthanum sulfate crystalline phase.

[0060] During the preparation of oxidant particles B, the calcination time is controlled between 2h and 8h.

[0061] On the other hand, a method for catalytic cracking of hydrocarbons to produce propylene and ethylene includes: catalytic cracking at a temperature of 500-700°C under the action of the above-mentioned catalyst.

[0062] The reaction time (i.e., residence time) is 1-5 seconds.

[0063] The mass ratio of catalyst to raw hydrocarbon is (2-50):1.

[0064] In the catalytic cracking process, the catalyst provided in this application can be used alone or in combination with other catalytic cracking catalysts. In some embodiments, when the catalyst of this application is used in combination with other catalytic cracking catalysts, the amount of the catalyst of this application is 2-50 wt%.

[0065] The products of catalytic cracking in this application have high selectivity for propylene and ethylene, and the propylene / ethylene ratio reaches more than 2.0, that is, the propylene content is increased.

[0066] In catalytic cracking reactions, the lanthanum sulfate (La2(SO4)3) crystal phase in the catalyst transforms into lanthanum oxysulfate ((LaO)2SO4) or lanthanum oxysulfate (La2O2S) after the reaction, resulting in a phase transformation, a change in the valence state of sulfur, and sulfur loss, thus deactivating the catalyst. Regeneration involves burning off carbon deposits and replenishing sulfur to restore the catalyst's crystal phase and catalytic activity.

[0067] The catalyst after the catalytic reaction is regenerated in an oxygen-containing atmosphere (such as air) at a temperature of 600-800℃.

[0068] In some implementations, sulfides and oxygen-containing gases are introduced again during the regeneration process.

[0069] The mass of sulfur in the sulfide is 1-5 wt% of the mass of component A in the catalyst particles.

[0070] The sulfides include, but are not limited to, one or more combinations of sulfur dioxide, thiophene, carbon disulfide, ammonium bisulfate, and ammonium sulfide.

[0071] The regeneration process can regenerate the deactivated catalyst during catalytic cracking, allowing it to be recycled and extending its lifespan.

[0072] The following specific examples further illustrate the method for preparing propylene and ethylene by catalytic cracking of alkanes, but this does not limit the scope of protection of this application. In the following examples and comparative examples, the conversion rate and yield are calculated as follows.

[0073] Conversion rate = (hydrocarbon content in raw material - hydrocarbon content in product) / hydrocarbon content in raw material × 100wt%

[0074] Ethylene yield = Ethylene content in product - Ethylene content in feedstock

[0075] Propylene yield = Propylene content in product - Propylene content in feedstock

[0076] propylene / ethylene = propylene yield / ethylene yield

[0077] The prepared catalysts were evaluated for performance on a fixed-bed microreactor. The preparation methods and reaction conditions for different catalysts are described in Examples 1-13.

[0078] Example 1

[0079] First, weigh out 0.31g of lanthanum nitrate (La(NO3)3). .Lanthanum nitrate solution (2.11% by mass) was prepared by dissolving 0.14 g of ammonium sulfate ((NH₄)₂SO₄) and 6H₂O in 9.46 g of water. 9.80 g of silica support was weighed and the solution was applied to the support in three separate applications. Between each application, the sample was dried in an oven at 110°C for 1 h. Finally, the sample was dried in an oven at 110°C for 3 h and then calcined at 800°C for 6 h. This sample was designated as particle A, and the lanthanum sulfate loading on particle A was 2%. (Lanthanum sulfate loading = mass of lanthanum sulfate / (mass of lanthanum sulfate + mass of support))

[0080] Prepare a 2% (w / w) cerium nitrate solution by mixing 0.2 g of cerium nitrate with 10.0 g of deionized water. Take 9.92 g of silica carrier and apply the solution to the carrier in three separate applications. Between each application, dry the sample in an oven at 110°C for 1 hour. Finally, dry the sample in an oven at 110°C for 3 hours, followed by calcination at 700°C for 3 hours. This sample is designated as particle B, and the cerium oxide loading on particle B is 0.8%. (Oxidant loading = oxidant mass / (oxidant mass + carrier mass))

[0081] Take 2g of particle A and 1g of particle B and mechanically mix them evenly to obtain the catalyst. In the catalyst, the mass ratio of lanthanum sulfate to cerium oxide is 5.

[0082] Example 2

[0083] First, weigh out 0.92g of lanthanum nitrate (La(NO3)3). . Lanthanum nitrate solution (2% by mass) was prepared by dissolving 0.42 g of ammonium sulfate ((NH4)2SO4) and 6H2O in 30 g of water. 9.4 g of silica gel was weighed and the solution was applied to the support in three portions. Between each portion, the sample was dried in an oven at 110 °C for 1 h. Finally, the sample was dried in an oven at 110 °C for 3 h and then calcined at 800 °C for 8 h. This sample was designated as particle A, with a lanthanum sulfate loading of 6%.

[0084] Prepare a 2% (w / w) cerium nitrate solution by mixing 0.25 g of cerium nitrate with 12.61 g of deionized water. Take 9.9 g of silica carrier and impregnate the carrier with the solution three times. Between each impregnation, dry the sample in an oven at 110°C for 1 hour. Finally, dry the sample in an oven at 110°C for 3 hours, and then calcine it at 800°C for 3 hours. This sample is designated as particle B, and the cerium oxide loading on particle B is 1%.

[0085] Take 2g of particle A and 0.8g of particle B and mechanically mix them evenly to obtain a catalyst. In the catalyst, the mass ratio of lanthanum sulfate to cerium oxide is 15.

[0086] Example 3

[0087] First, weigh out 1.53g of lanthanum nitrate (La(NO3)3). .Lanthanum nitrate solution (2% by mass) was prepared by dissolving 0.70 g of ammonium sulfate ((NH4)2SO4) in 50 g of water. 9 g of silica gel was weighed and the solution was applied to the support in three portions. Between each portion, the sample was dried in an oven at 110°C for 1 hour. Finally, the sample was dried in an oven at 110°C for 3 hours and then calcined at 800°C for 8 hours. This sample was designated as particle A, with a lanthanum sulfate loading of 10%.

[0088] Prepare a 2% (w / w) cerium nitrate solution by mixing 0.13 g of cerium nitrate and 6.31 g of deionized water. Apply the solution to the support silica in three separate applications, drying the sample in an oven at 110°C for 1 hour between each application. Finally, dry the sample in an oven at 110°C for 3 hours, followed by calcination at 800°C for 3 hours. This sample is designated as particle B, and the cerium oxide loading on particle B is 0.5%.

[0089] 2g of particle A and 0.8g of particle B were mechanically mixed evenly to obtain a catalyst. The mass ratio of lanthanum sulfate to cerium oxide in the catalyst was 50.

[0090] The catalyst prepared in this embodiment was subjected to X-ray powder diffraction, as shown in the attached figure. Figure 1 The XRD pattern shown indicates that the crystalline phase formed on the catalyst is the lanthanum sulfate phase.

[0091] Example 4

[0092] First, weigh out 1.84g of lanthanum nitrate (La(NO3)3). . Lanthanum nitrate solution (2.4% by mass) was prepared by dissolving 0.6 g of ammonium sulfate ((NH4)2SO4) and 0.84 g of ammonium sulfate in 50 g of water. 8.80 g of silica gel was weighed and the solution was applied to the support in three separate applications. Between each application, the sample was dried in an oven at 110 °C for 1 h. Finally, the sample was dried in an oven at 110 °C for 3 h and then calcined at 800 °C for 3 h. This sample was designated as particle A, with a lanthanum sulfate loading of 12%.

[0093] Prepare a 2% (w / w) cerium nitrate solution by mixing 0.05 g of cerium nitrate and 2.52 g of deionized water. Take 9.98 g of silica support and impregnate the support with the solution three times. Between each impregnation, dry the sample in an oven at 110°C for 1 hour. Finally, dry the sample in an oven at 110°C for 3 hours and then calcine it at 800°C for 3 hours. This sample is designated as particle B, and the cerium oxide loading on particle B is 0.2%.

[0094] Take 2g of particle A and 6g of particle B and mechanically mix them evenly to obtain a catalyst. In the catalyst, the mass ratio of lanthanum sulfate to cerium oxide is 20.

[0095] Example 5

[0096] First, weigh out 1.53g of lanthanum nitrate (La(NO3)3). . Lanthanum nitrate solution (2.0% by mass) was prepared by dissolving 0.70 g of ammonium sulfate ((NH4)2SO4) in 50 g of water. 9.00 g of silica gel was weighed and the solution was applied to the support in three portions. Between each portion, the sample was dried in an oven at 110 °C for 1 h. Finally, the sample was dried in an oven at 110 °C for 3 h and then calcined at 800 °C for 7 h. This sample was designated as particle A, with a lanthanum sulfate loading of 10%.

[0097] Prepare a 3% (w / w) cerium nitrate solution by mixing 0.2 g of cerium nitrate and 6.73 g of deionized water. Apply the solution to the support silica in three separate applications, drying the sample in an oven at 110°C for 1 hour between each application. Finally, dry the sample in an oven at 110°C for 3 hours, followed by calcination at 700°C for 5 hours. This sample is designated as particle B, and the cerium oxide loading on particle B is 0.8%.

[0098] Take 2g of particle A and 1.5g of particle B and mechanically mix them evenly to obtain the catalyst. In the catalyst, the mass ratio of lanthanum sulfate to cerium oxide is 17.

[0099] Example 6

[0100] First, weigh 0.58 g of lanthanum oxide (La₂O₃) and 0.53 g of concentrated sulfuric acid (98% H₂SO₄), and dissolve both reagents in 50 g of water to prepare a 2.0% (w / w) lanthanum nitrate solution. Weigh 9.00 g of silica gel support, and impregnate the support with the solution in three portions. Between the three portions, dry the sample in an oven at 110 °C for 1 h. Finally, dry the sample in an oven at 110 °C for 3 h, and then calcine it at 750 °C for 6 h. This sample is designated as particle A, and the lanthanum sulfate loading on particle A is 10%.

[0101] Prepare a 2% (w / w) cerium nitrate solution by mixing 0.15 g of cerium nitrate with 3.78 g of deionized water. Apply the solution to the support silica in three separate applications, drying the sample in an oven at 110°C for 1 hour between each application. Finally, dry the sample in an oven at 110°C for 3 hours, followed by calcination at 750°C for 5 hours. This sample is designated as particle B, and the cerium oxide loading on particle B is 0.6%.

[0102] Take 2g of particle A and 2g of particle B and mechanically mix them evenly to obtain a catalyst. In the catalyst, the mass ratio of lanthanum sulfate to cerium oxide is 17.

[0103] Example 7

[0104] First, weigh out 1.38g of lanthanum nitrate (La(NO3)3). .Lanthanum nitrate solution (1.80% by mass) was prepared by dissolving 0.63g of ammonium sulfate ((NH4)2SO4) in 50g of water. 9.10g of silica gel was weighed as a support, and the solution was applied to the support in three portions. Between each portion, the sample was dried in an oven at 110℃ for 1 hour. Finally, the sample was dried in an oven at 110℃ for 3 hours and then calcined at 800℃ for 4 hours. This sample was designated as particle A, with a lanthanum sulfate loading of 9%.

[0105] Take 0.02 g of vanadium pentoxide and dissolve it in 2 g of concentrated sulfuric acid, then slowly add deionized water for dilution. Take 9.98 g of silica support and impregnate the support with the solution in three batches. Between the three batches, the sample is dried in an oven at 110 °C for 1 h. Finally, the sample is dried in an oven at 110 °C for 3 h and then calcined at 730 °C for 5 h. This sample is called particle B, and the vanadium pentoxide loading on particle B is 0.2%.

[0106] Take 2g of particle A and 2g of particle B and mechanically mix them evenly to obtain a catalyst. In the catalyst, the mass ratio of lanthanum sulfate to vanadium pentoxide is 15.

[0107] Example 8

[0108] First, weigh out 1.07g of lanthanum nitrate (La(NO3)3). . Lanthanum nitrate solution (1.40% by mass) was prepared by dissolving 0.6 g of ammonium sulfate ((NH4)2SO4) and 0.49 g of ammonium sulfate in 50 g of water. 9.30 g of silica gel was weighed and the solution was applied to the support in three portions. Between each portion, the sample was dried in an oven at 110 °C for 1 h. Finally, the sample was dried in an oven at 110 °C for 3 h and then calcined at 800 °C for 7 h. This sample was designated as particle A, with a lanthanum sulfate loading of 7%.

[0109] Take 0.04 g of vanadium pentoxide and dissolve it in 2 g of concentrated sulfuric acid, then slowly add deionized water for dilution. Take 9.96 g of silica support and impregnate the support with the solution in three batches. Between the three batches, the sample is dried in an oven at 110 °C for 1 h. Finally, the sample is dried in an oven at 110 °C for 3 h and then calcined at 730 °C for 5 h. This sample is called particle B, and the vanadium pentoxide loading on particle B is 0.4%.

[0110] Take 2g of particle A and 2g of particle B and mechanically mix them evenly to obtain a catalyst. In the catalyst, the mass ratio of lanthanum sulfate to vanadium pentoxide is 18.

[0111] Example 9

[0112] First, weigh 0.63 g of lanthanum oxide (La₂O₃) and 0.58 g of concentrated sulfuric acid (98% H₂SO₄), and dissolve both reagents in 40 g of water to prepare a 2.75% (w / w) lanthanum nitrate solution. Weigh 8.90 g of silica gel support, and impregnate the support with the solution in three portions. Between the three portions, dry the sample in an oven at 110 °C for 1 h. Finally, dry the sample in an oven at 110 °C for 3 h, and then calcine it at 750 °C for 6 h. This sample is designated as particle A, and the lanthanum sulfate loading on particle A is 11%.

[0113] Take 0.33g of 50% manganese nitrate aqueous solution and add 5.49g of deionized water to prepare a 3% (w / w) manganese nitrate solution. Take 9.92g of silica carrier and impregnate the carrier with the solution in three stages. Between the three stages, the sample is dried in an oven at 110℃ for 1 hour. Finally, the sample is dried in an oven at 110℃ for 3 hours and then calcined at 750℃ for 5 hours. This is called particle B, and the manganese dioxide loading on particle B is 0.8%.

[0114] Take 2g of particle A and 1.5g of particle B and mechanically mix them evenly to obtain a catalyst. In the catalyst, the mass ratio of lanthanum sulfate to manganese dioxide is 14.

[0115] Example 10

[0116] First, weigh 0.58 g of lanthanum oxide (La₂O₃) and 0.53 g of concentrated sulfuric acid (98% H₂SO₄), and dissolve both reagents in 60 g of water to prepare a 1.67% (w / w) lanthanum nitrate solution. Weigh 8.90 g of silica gel support, and impregnate the support with the solution in three portions. Between the three portions, dry the sample in an oven at 110 °C for 1 h. Finally, dry the sample in an oven at 110 °C for 3 h, and then calcine it at 750 °C for 6 h. This sample is designated as particle A, and the lanthanum sulfate loading on particle A is 10%.

[0117] Prepare a mixed solution of cerium nitrate and manganese nitrate by mixing 0.05 g of manganese nitrate aqueous solution (50% concentration), 0.12 g of cerium nitrate, and 6.31 g of deionized water. Take 9.90 g of silica gel as a support and impregnate the support with the solution in three portions. Between each impregnation, the sample is dried in an oven at 110°C for 1 hour. Finally, the sample is dried in an oven at 110°C for 3 hours and then calcined at 750°C for 5 hours. This sample is designated as particle B, with a manganese dioxide loading of 0.5% and a cerium oxide loading of 0.5%.

[0118] Take 2g of particle A and 0.4g of particle B and mechanically mix them evenly to obtain a catalyst. In the catalyst, the mass ratio of lanthanum sulfate to oxidant (the sum of manganese dioxide and cerium oxide) is 100.

[0119] Example 11

[0120] First, weigh out 0.7g of lanthanum nitrate (La(NO3)3).. Lanthanum nitrate solution (1.75% by mass) was prepared by dissolving 0.49 g of ammonium sulfate ((NH4)2SO4) in 40 g of water. 9.30 g of magnesium aluminum spinel support was weighed and the solution was applied to the support in three stages. Between each stage, the sample was dried in an oven at 110 °C for 1 h. Finally, the sample was dried in an oven at 110 °C for 3 h and then calcined at 800 °C for 7 h. This sample was designated as particle A, with a lanthanum sulfate loading of 7%.

[0121] Dissolve 0.05 g of vanadium pentoxide in 2 g of concentrated sulfuric acid (98% H₂SO₄), and slowly add 20 g of deionized water. Then slowly add 0.05 g of 0.21 g of manganese nitrate aqueous solution (50% concentration). Prepare a mixed solution of vanadium and manganese. Take 9.90 g of magnesium aluminum spinel support, and impregnate the support with the solution in three batches. Between the three batches, dry the sample in an oven at 110 °C for 1 h. Finally, dry the sample in an oven at 110 °C for 3 h, and then calcine it at 750 °C for 5 h. This is called particle B. The loading of manganese dioxide and vanadium pentoxide on particle B is 0.5%.

[0122] Take 2g of particle A and 0.4g of particle B and mix them evenly to obtain a catalyst. In the catalyst, the mass ratio of lanthanum sulfate to oxidant (the sum of manganese dioxide and vanadium pentoxide) is 70.

[0123] Example 12

[0124] First, weigh out 1.22g of lanthanum nitrate (La(NO3)3). . Lanthanum nitrate solution (1.75% by mass) was prepared by dissolving 0.6 g of ammonium sulfate ((NH4)2SO4) and 0.56 g of ammonium sulfate in 50 g of water. 9.20 g of alumina support was weighed and the solution was applied to the support in three separate applications. Between each application, the sample was dried in an oven at 110 °C for 1 h. Finally, the sample was dried in an oven at 110 °C for 3 h and then calcined at 800 °C for 6 h. This sample was designated as particle A, with a lanthanum sulfate loading of 8%.

[0125] Dissolve 0.05 g of vanadium pentoxide in 3 g of concentrated sulfuric acid (98% H₂SO₄), and slowly add 20 g of deionized water. Take 9.95 g of alumina support and impregnate the support with the solution in three portions. Between the three portions, dry the sample in an oven at 110 °C for 1 h. Finally, dry the sample in an oven at 110 °C for 3 h, and then calcine it at 700 °C for 6 h. This sample is called particle B, and the vanadium pentoxide loading on particle B is 0.5%.

[0126] Take 2g of particle A and 0.4g of particle B and mechanically mix them evenly to obtain a catalyst. In the catalyst, the mass ratio of lanthanum sulfate to vanadium pentoxide is 80.

[0127] Example 13

[0128] First, weigh out 0.92g of lanthanum nitrate (La(NO3)3). . Lanthanum nitrate solution (1.5% by mass) was prepared by dissolving 0.42 g of ammonium sulfate ((NH4)2SO4) in 40 g of water. 9.40 g of magnesium aluminum hydrotalcite support was weighed and the solution was applied to the support in three separate applications. Between each application, the sample was dried in an oven at 110 °C for 1 h. Finally, the sample was dried in an oven at 110 °C for 3 h and then calcined at 800 °C for 4 h. This sample was designated as particle A, with a lanthanum sulfate loading of 6%.

[0129] Dissolve 0.06 g of vanadium pentoxide in 5 g of concentrated sulfuric acid (98% H₂SO₄), and slowly add 20 g of deionized water. Then slowly add 0.05 g of 0.25 g of manganese nitrate aqueous solution (50% concentration). Prepare a mixed solution of vanadium and manganese. Take 9.88 g of magnesium aluminum hydrotalcite support, and impregnate the support with the solution in three batches. Between the three batches, dry the sample in an oven at 110 °C for 1 h. Finally, dry the sample in an oven at 110 °C for 3 h, and then calcine it at 740 °C for 5 h. This is called particle B. The loading of manganese dioxide and vanadium pentoxide on particle B is 0.6%.

[0130] Take 2g of particle A and 0.3g of particle B and mechanically mix them evenly to obtain a catalyst. In the catalyst, the mass ratio of lanthanum sulfate to oxidant (the sum of manganese dioxide and vanadium pentoxide) is 60.

[0131] Example 14

[0132] In this embodiment, the catalyst used in the catalytic cracking of Example 3 (hereinafter referred to as the deactivated catalyst) is regenerated. Sulfur dioxide and air are introduced into the deactivated catalyst, wherein the mass of sulfur dioxide is 4% of the catalyst particles A. The reaction is carried out at a temperature of 700°C for 3 hours to obtain the regenerated catalyst.

[0133] Comparative Example 1

[0134] The catalyst in this comparative example was a silica gel support for chromatography, and no other substances were loaded onto the support.

[0135] Comparative Example 2

[0136] The catalyst in this comparative example was a silica support, and no other substances were loaded onto the support.

[0137] Comparative Example 3

[0138] The catalyst in this comparative example was a magnesium aluminum hydrotalcite support, and no other substances were loaded on the support.

[0139] Comparative Example 4

[0140] The catalyst in this comparative example was an alumina support, and no other substances were loaded onto the support.

[0141] The catalytic performance results in Table 1 show that the pure support catalysts in Comparative Examples 1-4 have limited catalytic performance; while the catalysts supported with lanthanum sulfate have high propylene yields.

[0142] Comparative Example 5

[0143] ZSM-5 molecular sieve with a silica-to-alumina ratio of 38 (purchased from Tianjin Nanhua Catalyst Co., Ltd.) was used as the active component, with a ZSM-5 molecular sieve content of 30% and the remainder being a silica support. During preparation, 10g of ZSM-5 molecular sieve was added to 77.77g of silica sol (30% silica content), then dried in an oven at 110℃ for approximately 6 hours, followed by calcination in air at 800℃ for 6 hours.

[0144] Comparative Example 6

[0145] ZSM-5 molecular sieve with a silicon-to-aluminum ratio of 38 (purchased from Tianjin Nanhua Catalyst Co., Ltd.) was used as the active component, with ZSM-5 molecular sieve comprising 40% of the composition, and the remainder being a silica support. During preparation, 10g of ZSM-5 molecular sieve was added to 58.33g of silica sol (30% silica content), then dried in an oven at 110℃ for approximately 6 hours, followed by calcination in air at 800℃ for 6 hours.

[0146] Catalyst Evaluation: The reaction performance of the catalysts prepared in Examples 1-14 and Comparative Examples 1-6 was evaluated in a micro fixed-bed reactor. The reactant was n-butane (n-butane, 99.99% by volume, produced by Qingdao Deyi Gas Co., Ltd., Shandong Province). The quartz tube reactor had dimensions of Φ12×300mm. The catalyst consisted of 80-120 mesh particles and was packed in the middle of the reactor at a loading of 2g. The reaction temperature was 650℃, and N2 was used for protection during the heating process. The n-butane feed space velocity was 0.36h⁻¹. -1 The reaction product was collected after 3 minutes of reaction and 12 minutes of reaction.

[0147] The reaction products were analyzed using a Fuli GC9720plus gas chromatograph manufactured by Zhejiang Fuli Analytical Instrument Co., Ltd. Hydrocarbons were detected using an FID detector on an HT-PLOT Al2O3 S capillary column, while carbon dioxide and carbon monoxide were detected using a TCD detector on an HP-INNOWax capillary column.

[0148] Results Analysis: Compared with the unloaded comparative examples 1, 2, 3, and 4, the yields of ethylene and propylene increased to varying degrees after loading, especially the propylene yield. The propylene / ethylene yield ratio of the loaded catalysts reached a maximum of 3.01. Compared with conventional catalysts using molecular sieves as the active component (comparative examples 5 and 6), the propylene / ethylene yield ratios of the catalysts were also higher.

[0149] Table 1 Butane conversion and yield

[0150]

[0151]

Claims

1. A catalyst for catalytic cracking of hydrocarbons, comprising lanthanum sulfate and metal oxides; wherein the metal oxides include cerium oxides, oxides of Group VIII metals, oxides of Group VB metals, or oxides of Group VIIB metals.

2. The catalyst according to claim 1, characterized in that, Metal oxides include one or more of the following: cerium oxides, vanadium oxides, iron oxides, and manganese oxides; Preferably, the metal oxide includes one or more of cerium oxide, vanadium pentoxide, iron oxide, or manganese dioxide.

3. The catalyst according to claim 1 or 2, characterized in that, The mass ratio of lanthanum sulfate to metal oxide in the catalyst is (5-100):1; Preferably, the mass ratio of lanthanum sulfate to cerium oxide in the catalyst is (40-60):

1.

4. The catalyst according to claim 1 or 2, characterized in that, The catalyst includes lanthanum sulfate, metal oxides, and a support. Lanthanum sulfate is loaded onto the support, and the proportion of lanthanum sulfate to the total mass of the support and lanthanum sulfate is 2-20 wt%. Preferably, the metal oxide is loaded onto the support, and the proportion of the metal oxide to the total mass of the support and the metal oxide is 0.1-10 wt%. The carrier includes one or more of amorphous silica, chromatographic silica gel, magnesium aluminum spinel, zinc aluminum spinel or magnesium aluminum hydrotalcite.

5. A method for preparing the catalyst according to any one of claims 1-4, comprising: Lanthanum source and sulfur source are mixed to form a mixed solution, which is then impregnated onto a support. After drying and calcination, lanthanum sulfate particles A are obtained. The calcination temperature is 600-800℃. Metal salt solution is impregnated onto a carrier, and after drying and calcination, oxidant particles B are obtained. The calcination temperature is 600-800℃. The metals include cerium, Group VIII metals, Group VB metals or Group VIIB metals. Lanthanum sulfate particles A and oxidant particles B are mechanically mixed to obtain a lanthanum sulfate catalyst. Preferably, the lanthanum source includes one or more of lanthanum nitrate, lanthanum oxide, or lanthanum carbonate; the sulfur source includes, but is not limited to, one or more of sulfuric acid, ammonium sulfate, or ammonium bisulfate. Soluble metal salts include soluble nitrates.

6. The method according to claim 5, characterized in that, In the mixed solution, the molar ratio of La to S is 2:(3-5).

7. The method according to claim 5 or 6, characterized in that, In the process of preparing lanthanum sulfate particles A, the calcination time is 1h-12h; Preferably, the calcination time is controlled between 2h and 8h during the preparation of oxidant particles B.

8. A method for catalytic cracking of hydrocarbons to produce propylene and ethylene, including: Catalytic cracking is carried out at a temperature of 500-700°C under the action of the catalyst described in any one of claims 1-4; Preferably, the reaction time is 1s-5s. More preferably, the mass ratio of catalyst to raw hydrocarbon is (2-50):

1.

9. The method according to claim 8, characterized in that, When the catalyst is used in combination with other catalytic cracking catalysts, the amount of the catalyst is 2-50 wt%. Preferably, the hydrocarbons include one or more of the following: alkanes, alkenes, wax oils, naphtha, gasoline, diesel, crude oil, or residual oil.

10. The method according to claim 8, characterized in that, The catalyst after the catalytic cracking reaction is regenerated in an oxygen-containing atmosphere at a temperature of 600-800℃; Preferably, during the regeneration process, sulfides and oxygen-containing gases are introduced, and the regeneration temperature is 600-800℃; Preferably, the mass of sulfur in the sulfide is 1-5 wt% of the mass of component A of the catalyst particles; Preferably, the sulfide includes one or more of sulfur dioxide, thiophene, carbon disulfide, ammonium bisulfate, and ammonium sulfide.

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