Catalyst composition and process for treating carbon four containing feedstocks

Abstract

The present application relates to the field of processing of hydrocarbon feedstock, and particularly relates to a catalyst composition and a processing method of feedstock containing carbon four. The composition comprises: component A: alumina loaded with a hydrogenation active component; component B: ZSM-5 molecular sieve loaded with a modifying element, the modifying element being selected from at least one of group IIB elements, group IIIA elements and group VA elements. The catalyst composition of the present application couples the alumina loaded with the hydrogenation active component and the ZSM-5 molecular sieve loaded with the modifying element, synergistically enhances the catalytic effects of both, and improves the catalytic performance of the catalyst composition.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of processing of hydrocarbon feedstocks, in particular to a catalyst composition and a method for processing a carbon four-containing feedstock. BACKGROUND

[0002] In recent years, with the continuous optimization of raw materials by domestic refining enterprises, cracking raw materials are facing the direction of lightening, that is, from heavy cracking materials mainly composed of naphtha to light hydrocarbons, petroleum gas, natural gas and other gas resources. The production route of light cracking raw materials has the advantages of high diene product yield, low cost, low energy consumption and small pollution. Compared with medium / heavy raw materials, the diene yield is more than doubled when producing diene with light cracking raw materials. For example, when cracking ethane and propane, the main product is ethylene, and the yield is more than 60%. The yield of propylene produced by propane dehydrogenation process is higher, which can reach more than 80%.

[0003] Liquefied petroleum gas is a by-product of refining devices, mainly containing carbon four components, and a small amount of propane and components above carbon five. China is rich in liquefied petroleum gas resources, especially the rapid development of new energy industry and the large-scale replacement of natural gas for civilian liquefied gas. Liquefied petroleum gas resources are facing a large surplus. These light hydrocarbon resources have not been well utilized in China and are mainly used as fuel, resulting in great waste of resources. Carbon four components mainly contain isobutane, n-butane, n-butene, isobutene and a small amount of butadiene. Due to the high content of olefins in the composition, it cannot be directly used as a cracking device raw material. Among the alkanes in the carbon four raw material, isomeric alkanes are more common, and the diene yield is also relatively low when used as cracking material. Therefore, liquefied petroleum gas and other carbon four raw materials are not suitable as cracking device raw materials.

[0004] With the expansion of the scale of cracking devices in China, the demand for light hydrocarbon resources is increasing, and many methods have been used to produce cracking materials.

[0005] 201110143584.4 discloses a catalyst for producing propane and high-octane gasoline from butane, specifically hydrogen-type mesoporous silica-alumina zeolite, and the propane yield can reach 25-55%.

[0006] CN112588314A discloses a catalyst for producing propane from light hydrocarbons and a preparation method thereof. The catalyst is a metal-supported molecular sieve that can efficiently convert light hydrocarbon raw materials such as liquefied gas and naphtha into propane, and the propane selectivity can reach more than 70%.

[0007] The above methods for producing light hydrocarbons use alkanes as raw materials and do not contain olefins. However, when using raw materials containing olefins to produce light hydrocarbons, the catalyst is easily deactivated, and the amount of light hydrocarbons obtained is relatively small.

[0008] The feedstock for ethylene cracking units requires an olefin content of less than 2%, therefore, C4 feedstocks containing a large amount of olefins are not suitable for direct use as feedstock for cracking units. Summary of the Invention

[0009] Liquefied petroleum gas (LPG) and other C4 resources are relatively abundant in my country. However, using LPG and other C4 resources to produce pyrolysis feedstock presents two main problems: First, the feedstock contains a high proportion of olefins, making it unsuitable for direct use as pyrolysis feedstock. Second, the proportion of isoalkanes in the feedstock is high, resulting in a low diene yield when used as pyrolysis feedstock. Therefore, the purpose of this invention is to overcome these problems by providing a catalyst composition and a method for processing C4-containing feedstocks. Using the catalyst composition and processing method provided by this invention, C4 feedstocks such as LPG can be converted into high-quality pyrolysis feedstocks ethane and propane with high yields.

[0010] To achieve the above objectives, a first aspect of the present invention provides a catalyst composition comprising: component A: alumina supported on a hydrogenation active component; and component B: ZSM-5 molecular sieve supported on a modifying element, wherein the modifying element is selected from at least one of Group IIB, Group IIIA, and Group VA elements.

[0011] A second aspect of the present invention provides a method for processing a C4-containing feedstock, the method comprising: contacting the C4-containing feedstock with a catalyst under a hydrogen-containing atmosphere to obtain a diene cracking feedstock; wherein the catalyst comprises the composition described in the first aspect.

[0012] Through the above technical solution, the present invention has the following advantages:

[0013] The catalyst composition of the present invention couples alumina loaded with hydrogenation active components and ZSM-5 molecular sieve loaded with modifying elements, which synergistically enhances the catalytic effect of the two and improves the catalytic performance of the catalyst composition.

[0014] Using the catalyst composition of the present invention to process C4-containing feedstocks (such as liquefied petroleum gas) can efficiently convert the feedstocks into ethane and propane, resulting in high-quality diene cracking feedstock. Detailed Implementation

[0015] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0016] The present invention provides a catalyst composition comprising: component A: alumina supported on a hydrogenation active component; component B: ZSM-5 molecular sieve supported on a modifying element, wherein the modifying element is selected from at least one of Group IIB, Group IIIA and Group VA elements.

[0017] The catalyst composition of the present invention couples alumina loaded with hydrogenation active components and molecular sieve loaded with modifying elements, which synergistically enhances the catalytic effect of the two and improves the catalytic performance of the catalyst composition.

[0018] According to a preferred embodiment of the present invention, the content of the modifying element in component B is 0.5-3 wt%. By adopting the aforementioned preferred embodiment, the catalytic performance of the composition can be further improved.

[0019] According to a preferred embodiment of the present invention, the modifying element comprises at least two of Group VA elements, Group IIB elements, and Group IIIA elements: when Group VA elements are included, the ratio of the total molar amount of Group IIB elements and / or Group IIIA elements to the molar amount of Group VA elements is 1.5-3.0; when Group VA elements are not included, the molar ratio of Group IIB elements to Group IIIA elements is 0.1-5.0.

[0020] According to a preferred embodiment of the present invention, the Group IIB element is selected from Zn and / or Cd, preferably Zn.

[0021] According to a preferred embodiment of the present invention, the Group IIIA element is selected from Ga and / or In, preferably Ga.

[0022] According to a preferred embodiment of the present invention, the Group VA element is selected from at least one of P, As, and Sb, preferably P.

[0023] According to a preferred embodiment of the present invention, component B further contains a binder, preferably in the form of 30-50 wt%. By adopting the aforementioned preferred embodiment, the catalytic performance of the composition can be further improved.

[0024] According to a preferred embodiment of the present invention, the binder is selected from at least one of alumina and boehmite.

[0025] According to a preferred embodiment of the present invention, the SiO2 / Al2O3 molar ratio of the molecular sieve in component B is 40-120. By adopting the aforementioned preferred embodiment, the catalytic performance of the composition can be further improved.

[0026] According to a preferred embodiment of the present invention, the content of the hydrogenation active component in component A, calculated as oxide, is 18-29 wt%.

[0027] According to a preferred embodiment of the present invention, the hydrogenation active component comprises at least one of a Group VIB metal element and a Group VIII metal element.

[0028] According to a preferred embodiment of the present invention, the hydrogenation active component in component A comprises a Group VIB metal and a Group VIII metal. Preferably, based on the total weight of component A, the content of the Group VIB metal as oxide is 10-16 wt%, and the content of the Group VIII metal as oxide is 8-13 wt%. By adopting the aforementioned preferred embodiment, the catalytic performance of the composition can be further improved.

[0029] According to a preferred embodiment of the present invention, the alumina in component A contains γ-alumina, preferably γ-alumina.

[0030] According to a preferred embodiment of the present invention, the Group VIB metal is selected from molybdenum and / or chromium, preferably molybdenum.

[0031] According to a preferred embodiment of the present invention, the Group VIII metal is selected from at least one of nickel, palladium and platinum, preferably nickel.

[0032] According to a preferred embodiment of the present invention, the volume ratio of component A to component B in the composition is 1-3, preferably 1.5-2.5.

[0033] In this invention, the preparation methods of components A and B in the catalyst composition are not particularly required. According to this invention, the preparation method of component A can be an impregnation method: an alumina support is impregnated in a solution containing a hydrogenation active component. The impregnation conditions are not particularly required; for example, the alumina can be placed in the impregnation solution at a solid-liquid volume ratio of 1:3 for 2 hours, then removed and dried at 60°C overnight, followed by calcination at 450°C for 6 hours. This process is repeated once to obtain component A. The preparation method of component B can be an impregnation method: a molecular sieve is mixed with a binder, an inorganic acid is added, and the mixture is kneaded, extruded, dried, and calcined. The drying and calcination conditions are not required. The support obtained by calcination is impregnated with a solution containing a modifying element, and then dried and calcined again to obtain component B. The drying and calcination conditions are not required; for example, the drying can be carried out at 110°C for 10 hours and calcined at 500°C for 6 hours.

[0034] This invention provides a method for processing a C4-containing raw material, the method comprising: contacting the C4-containing raw material with a catalyst under a hydrogen-containing atmosphere to obtain a diene cracking feedstock; wherein the catalyst comprises the composition described in this invention.

[0035] Using the catalyst composition of the present invention to process C4-containing feedstocks (such as liquefied petroleum gas) can efficiently convert the feedstocks into ethane and propane, resulting in high-quality diene cracking feedstock.

[0036] In this invention, components A and B in the composition can be used in combination or in layers.

[0037] According to a preferred embodiment of the present invention, the content of C4 component in the C4-containing raw material is not less than 60 wt%.

[0038] According to a preferred embodiment of the present invention, the C4-containing raw material is selected from liquefied petroleum gas and / or C4 after etherification.

[0039] According to a preferred embodiment of the present invention, the contact conditions include: a volume hourly space velocity (VHSV) of 1-10 h⁻¹ for the C₄-containing feedstock. -1 .

[0040] According to a preferred embodiment of the present invention, the contact conditions include a volume ratio of hydrogen to C4-containing raw material of 50-300:1.

[0041] According to a preferred embodiment of the present invention, the contact conditions include a reaction temperature of 300-400°C.

[0042] According to a preferred embodiment of the present invention, the contact conditions include a reaction pressure of 2-6 MPa.

[0043] The present invention will be described in detail below through examples. In the following examples, the elemental composition of the catalyst was determined by ICP; unless otherwise specified, the raw materials are all commercially available products.

[0044] Example 1

[0045] Catalyst preparation methods:

[0046] Take 40 grams of the shaped γ-alumina strips and prepare solutions of 12.2 wt% ammonium molybdate and 9.4 wt% nickel nitrate. Immerse the strips in the solutions at a solid-liquid volume ratio of 1:3 for 2 hours, then remove and dry at 60°C overnight, followed by calcination at 450°C for 6 hours. Repeat this process once to obtain component A1. Elemental composition was determined by ICP. Based on the mass of component A1, the molybdenum oxide content was 11.2%, and the nickel oxide content was 8.6%.

[0047] 100.0 g of ZSM-5 molecular sieve powder with a SiO2 / Al2O3 molar ratio of 45 was mixed with 30 g of alumina. Dilute nitric acid was added, and the mixture was kneaded, extruded, and calcined after drying. 14 g of a 2.8 wt% zinc nitrate solution was prepared and added to 20 g of the shaped carrier. The mixture was then dried at 110 °C for 10 hours and calcined at 500 °C for 6 hours to obtain component B1. The elemental composition was determined by ICP analysis. Based on the mass of component B1, the zinc oxide content was 1.2%.

[0048] Example 2

[0049] Catalyst preparation methods:

[0050] Take 50 grams of the shaped γ-alumina strips and prepare solutions of 8.4 wt% ammonium molybdate and 7.7 wt% nickel nitrate, respectively. Immerse the strips in the solutions at a solid-liquid volume ratio of 1:3 for 2 hours, then remove and dry at 60°C overnight, followed by calcination at 450°C for 6 hours. Repeat this process twice to obtain component A2. Elemental composition was determined by ICP. Based on the mass of component A2, the molybdenum oxide content was 15.2%, and the nickel oxide content was 12.6%.

[0051] 80.0 g of ZSM-5 molecular sieve powder with a SiO2 / Al2O3 molar ratio of 110 was mixed with 35 g of alumina. Dilute nitric acid was added, and the mixture was kneaded, extruded, and calcined after drying. 20 g of a 5.6 wt% gallium nitrate solution was prepared and added to 30 g of the shaped support. The mixture was then dried at 110 °C for 10 hours and calcined at 500 °C for 6 hours to obtain component B2. The elemental composition was determined by ICP; the gallium oxide content, based on the mass of component B2, was 2.8%.

[0052] Example 3

[0053] Catalyst preparation methods:

[0054] The preparation method of the catalyst in Part A is the same as in Example 1;

[0055] 100.0 g of ZSM-5 molecular sieve powder with a SiO2 / Al2O3 molar ratio of 80 was mixed with 30 g of alumina. Dilute nitric acid was added, and the mixture was kneaded, extruded, and calcined after drying. 20 g of a 1.8 wt% zinc nitrate solution, 1.0 wt% gallium nitrate, and 1.1 wt% diammonium hydrogen phosphate solution were prepared. This solution was added to 34 g of the shaped support, and the mixture was dried at 110 °C for 10 hours and calcined at 500 °C for 6 hours to obtain component B3. The elemental composition was determined by ICP. Based on the mass of component B3, the content of zinc oxide was 1.2%, the content of gallium oxide was 0.8%, and the content of phosphorus was 0.7%.

[0056] Example 4

[0057] Catalyst preparation methods:

[0058] The preparation method of the catalyst in Part A is the same as in Example 1;

[0059] 100.0 g of ZSM-5 molecular sieve powder with a SiO2 / Al2O3 molar ratio of 100 was mixed with 30 g of alumina. Dilute nitric acid was added, and the mixture was kneaded, extruded, and calcined after drying. 16 g of a 2.0 wt% zinc nitrate solution and 1.0 wt% gallium nitrate solution were prepared. This solution was added to 23 g of the shaped support, and the mixture was dried at 110℃ for 10 hours and calcined at 500℃ for 6 hours to obtain component B4. The elemental composition was determined by ICP. Based on the mass of component B4, the content of zinc oxide was 1.7%, and the content of gallium oxide was 0.8%.

[0060] Example 5

[0061] Catalyst preparation methods:

[0062] The preparation method of the catalyst in Part A is the same as in Example 1;

[0063] 100.0 g of silicate molecular sieve powder with a SiO2 / Al2O3 molar ratio of 18 was mixed with 30 g of alumina. Dilute nitric acid was added, and the mixture was kneaded, extruded, and calcined after drying. 16 g of a 2.0 wt% zinc nitrate solution and 1.0 wt% gallium nitrate solution were prepared. This solution was added to 23 g of the shaped support, and the mixture was dried at 110 °C for 10 hours and calcined at 500 °C for 6 hours to obtain component B5. The elemental composition was determined by ICP. Based on the mass of component B5, the content of zinc oxide was 1.8%, and the content of gallium oxide was 0.7%.

[0064] Example 6

[0065] Liquefied petroleum gas (composition shown in Table 1) was introduced into a reactor (segmented loading, loading volume ratio shown in Table 2) sequentially loaded with component A and component B (catalysts prepared in Examples 1-5). The reaction was carried out at a pressure of 3 MPa, a temperature of 360 °C, and a volume hourly space velocity (VHSV) of 4 h⁻¹. -1 Under the conditions of 200:1 volume ratio of hydrogen to liquefied petroleum gas, the reaction results are shown in Table 2.

[0066] The catalyst ratios are listed in Table 2

[0067] Comparative Example 1

[0068] Liquefied petroleum gas (composition shown in Table 1) is introduced into a reactor containing only component A. The reaction pressure is 3 MPa, the reaction temperature is 360 °C, and the volume hourly space velocity of the liquefied petroleum gas is 4 h⁻¹. -1 Under the conditions of 200:1 volume ratio of hydrogen to liquefied petroleum gas, the reaction results are shown in Table 2.

[0069] Comparative Example 2

[0070] Liquefied petroleum gas (composition shown in Table 1) is introduced into a reactor containing only component B. The reaction pressure is 3 MPa, the reaction temperature is 360 °C, and the volume hourly space velocity of the liquefied petroleum gas is 4 h⁻¹. -1 Under the conditions of 200:1 volume ratio of hydrogen to liquefied petroleum gas, the reaction results are shown in Table 2.

[0071] Table 1 Composition of Liquefied Petroleum Gas

[0072]

[0073]

[0074] Table 2

[0075]

[0076] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A process for treating a carbon four containing feedstock, characterized by, The method comprises: contacting a carbon four-containing raw material with a catalyst under a hydrogen-containing atmosphere to obtain a diene cracking material; The catalyst is a catalyst composition, and the catalyst composition comprises: Component A: alumina supporting a hydrogenation active component; Component B: ZSM-5 molecular sieve supporting a modifying element, the modifying element being at least one selected from a group consisting of a group II B element, a group III A element and a group VA element.

2. The treatment method according to claim 1, wherein, the content of the modifying element in the component B is 0.5-3 wt%; and / or the modifying element comprises at least two of a group VA element, a group II B element and a group III A element: when the group VA element is contained, the ratio of the total molar amount of the group II B element and / or the group III A element to the molar amount of the group VA element is 1.5-3.0; when the group VA element is not contained, the ratio of the molar amount of the group II B element to the molar amount of the group III A element is 0.1-5.

0.

3. The treatment method according to claim 1, wherein, the group II B element is selected from Zn and / or Cd; and / or the group III A element is selected from Ga and / or In; and / or the group VA element is at least one selected from P, As and Sb.

4. The treatment method according to claim 1, wherein, the group II B element is Zn; and / or the group III A element is Ga; and / or the group VA element is P.

5. The treatment method of claim 1, wherein, The component B further contains a binder.

6. The treatment method of claim 5, wherein, The content of the binder in the component B is 30-50 wt%.

7. The treatment method according to claim 5, wherein, the binder is at least one selected from alumina and pseudo-boehmite; and / or the SiO2 / Al2O3 molar ratio of the molecular sieve in the component B is 40-120.

8. The treatment method of claim 1, wherein, The content of the hydrogenation active component in the component A is 18-29 wt% in terms of oxide.

9. The treatment method of claim 1, wherein, The hydrogenation active component comprises at least one of a group VI B metal element and a group VIII metal element.

10. The treatment method of claim 1, wherein, The hydrogenation active component in the component A comprises a group VI B metal and a group VIII metal.

11. The treatment method of claim 10, wherein, The content of the group VI B metal is 10-16 wt% in terms of oxide, and the content of the group VIII metal is 8-13 wt% in terms of oxide, based on the total weight of the component A.

12. The treatment method according to claim 10, wherein, the group VI B metal is selected from molybdenum and / or chromium; and / or the group VIII metal is at least one selected from nickel, palladium and platinum; and / or the alumina in the component A contains gamma alumina.

13. The treatment method according to claim 12, wherein, the group VI B metal is molybdenum; and / or the group VIII metal is nickel.

14. The treatment method of claim 1, wherein, The volume ratio of the component A to the component B in the composition is 1-3.

15. The treatment method of claim 14, wherein, The volume ratio of the component A to the component B in the composition is 1.5-2.

5.

16. The treatment method of claim 1, wherein, The content of the carbon four component in the carbon four-containing raw material is not less than 60 wt%.

17. The treatment method of claim 1, wherein, The carbon four-containing raw material is selected from liquefied petroleum gas and / or ether post carbon four.

18. The treatment method according to any one of claims 1-17, wherein, The contacting conditions comprise: The carbon four containing feedstock has a volume space velocity of 1-10 h -1 ; and / or the volume ratio of hydrogen to the carbon four-containing raw material is 50-300:1; and / or the reaction temperature is 300-400℃; and / or the reaction pressure is 2-6 MPa.

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