Isoparaffin conversion method and system capable of flexibly adjusting conversion product composition

Abstract

The invention relates to an isoparaffin conversion method and system capable of flexibly adjusting the composition of a conversion product. The isoparaffin conversion method capable of flexibly adjusting the composition of the conversion product comprises the following steps: 1) providing a hydrocarbon material flow containing C5-C6 isoparaffin, 2) carrying out a conversion reaction on at least one part of the C5-C6 isoparaffin in the presence of a molecular sieve with shape-selective catalytic performance and hydrogen, a conversion product comprising C2-C3 hydrocarbons and C4-C6 n-alkanes is obtained. According to the invention, the selective conversion of isoparaffin can be realized, and the ratio of C2-C3 hydrocarbon to C4-C6 n-alkane in the conversion product can be flexibly adjusted, so that the structure of an ethylene product can be flexibly adjusted, and the product flexibility of an ethylene device is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of petrochemical engineering, and in particular to a method and system for converting isoparaffins capable of flexibly adjusting the composition of conversion products. Background Art

[0002] When isoparaffins are used as ethylene raw materials, their ethylene yield and triene yield are both low. Therefore, effectively converting isoparaffins into normal paraffins can greatly increase the yield of high-value products in ethylene plants. Among normal paraffins, low-carbon paraffins (including ethane and propane) are better cracking raw materials, with low separation difficulty and high ethylene product yield. However, more hydrogen is consumed in the process of obtaining ethane and propane through hydrogenation conversion; while C4 and C 4+ Normal alkanes can also achieve a higher ethylene yield due to the existence of isomers, and less hydrogen is consumed during the hydrogenation conversion process. However, it is difficult to separate isomeric hydrocarbons with the same carbon number, and isomeric hydrocarbons are usually entrained in the hydrogenation product, and its ethylene yield will be lower than that when low-carbon alkanes are used as raw materials. If the ratio of low-carbon alkanes and normal alkanes in the hydrogenation product can be flexibly adjusted through the hydrogenation conversion process, the operational flexibility can be greatly improved.

[0003] With the rapid development of my country's chemical industry, the production capacity of ethylene has increased year by year. Therefore, the demand for ethylene raw materials has also continued to increase. How to broaden the selection range of ethylene raw materials and how to obtain high-quality ethylene raw materials have become urgent issues that need to be solved in the development of the ethylene industry. Summary of the invention

[0004] The inventors of the present invention have found that small molecular isoalkanes mainly undergo two reaction processes during the hydrogenation conversion process: cracking and normalization. The cracking reaction can convert more low-carbon alkanes, while the normalization reaction converts isoalkanes with the same carbon number into normal alkanes. By adjusting the catalyst and process conditions, the molecular composition of the hydrogenation product can be flexibly adjusted, thereby improving the flexibility of production.

[0005] Specifically, the present invention relates to the following aspects.

[0006] 1. A method for converting isoparaffins, comprising the following steps:

[0007] 1) providing a hydrocarbon stream containing C5-C6 isoparaffins,

[0008] 2) subjecting at least a portion (e.g., more than 30 wt%, more than 40 wt%, more than 50 wt%, more than 60 wt%, more than 70 wt%, more than 80 wt% or more than 90 wt%) of the C5-C6 isoparaffins to a conversion reaction in the presence of a molecular sieve having shape-selective catalytic performance and hydrogen to obtain a conversion product comprising C2-C3 hydrocarbons and C4-C6 normal alkanes (preferably C5-C6 normal alkanes), and

[0009] 3) Optionally steam cracking the conversion product to obtain a cracking product comprising ethylene.

[0010] 2. A method according to any of the preceding or following aspects, wherein the weight ratio of the C2-C3 hydrocarbons to the C4-C6 normal alkanes (preferably C5-C6 normal alkanes) in the conversion product is 0.5:1-8:1 (preferably 0.9:1-5:1).

[0011] 3. The method according to any one of the preceding or following aspects, wherein the hydrocarbon stream has an initial boiling point of 10-30°C (preferably 15-25°C) and a final boiling point of 50-100°C (preferably 55-70°C).

[0012] 4. A method according to any of the preceding or following aspects, wherein the hydrocarbon stream contains 0-10 wt% C7+ hydrocarbons (preferably 0.5-5 wt%), 50 wt% C5-C6 isoparaffins (preferably 60-90 wt%, more preferably 70-80 wt%), 10-30 wt% C5-C6 normal paraffins (preferably 15-25 wt%), 0-10 wt% C4- hydrocarbons (preferably 2-5 wt%), 10-10 wt% cyclic hydrocarbons (preferably 0.5-10 wt%), and 10-20 wt% C5-C6 isoparaffins (preferably 0.5-20 wt%). 2-5wt%), based on the total weight of the hydrocarbon stream as 100wt%, and / or, the content of C7+ hydrocarbons in the conversion product is not higher than 5wt% (preferably not higher than 1wt%), the content of C5-C6 isoparaffins is 0-50wt% (preferably 10-40wt%), the content of C2-C6 normal paraffins is 40-90wt% (preferably 50-80wt%), and the content of cyclic hydrocarbons is not higher than 3wt% (preferably not higher than 1wt%), based on the total weight of the conversion product as 100wt%.

[0013] 5. The process according to any one of the preceding or following aspects, wherein the hydrocarbon stream is a light naphtha component obtained by subjecting a hydrocarbon oil feedstock to cracking (such as hydrocracking or catalytic cracking).

[0014] 6. The method according to any one of the preceding or following aspects, wherein the conversion reaction is carried out in the presence of a catalyst, and the catalyst comprises the molecular sieve and an active metal component.

[0015] 7. The method according to any of the preceding or following aspects, wherein the molecular sieve is a molecular sieve having shape-selective catalytic properties, preferably selected from one or more of mordenite, ZSM molecular sieve, SAPO molecular sieve and EU-1 molecular sieve, more preferably selected from one or more of mordenite and ZSM molecular sieve, particularly preferably selected from one or more of mordenite, ZSM-5 molecular sieve, ZSM-11 molecular sieve, ZSM-12 molecular sieve, ZSM-22 molecular sieve, ZSM-23 molecular sieve, ZSM-35 molecular sieve, Beta molecular sieve and ZSM-38 molecular sieve, in particular selected from one or more of mordenite and ZSM-5 molecular sieve, and particularly preferably the weight ratio of mordenite to ZSM-5 molecular sieve is 0-100:100-0 (preferably 10-50:50-10).

[0016] 8. A method according to any of the preceding or following aspects, wherein the catalyst further comprises a binder (preferably alumina), and the content of the binder is 5-65wt% (preferably 10-35wt%) based on the weight of the catalyst.

[0017] 9. A method according to any of the preceding or following aspects, wherein the active metal component is at least one of a metal, a metal oxide, and a metal sulfide of an active metal component; the active metal is selected from one or more of a Group VIB metal and a Group VIII non-precious metal, the Group VIB metal is preferably selected from one or more of molybdenum and tungsten (particularly molybdenum is preferred), and the Group VIII non-precious metal is preferably selected from one or more of cobalt and nickel (particularly preferably nickel).

[0018] 10. A method according to any of the preceding or following aspects, wherein the content of the VIB Group metal (calculated as oxide) is 5.0-30.0 wt% (preferably 10-20 wt%), and the content of the VIII Group non-noble metal (calculated as oxide) is 0.5-15.0 wt% (preferably 3-10 wt%), based on the weight of the catalyst.

[0019] 11. A method according to any of the preceding or following aspects, wherein the molecular sieve content is 30-80 wt% (preferably 40-70 wt%) based on the weight of the catalyst.

[0020] 12. A method according to any of the preceding or following aspects, wherein the catalyst has a specific surface area of ​​200-400 m 2 / g, and the pore volume is 0.25-0.45mL / g.

[0021] 13. A method according to any of the preceding or following aspects, wherein the reaction conditions of the conversion reaction include: a reaction pressure of 0.5-10.0 MPaG (preferably 2.0-8.0 MPaG or 2.0-5.0 MPaG), a reaction temperature of 250-500° C. (preferably 350-450° C.), a liquid hourly volume space velocity of 0.1-15.0 h -1 (Preferably 0.5-5.0h -1 ), the volume ratio of hydrogen to oil is 10:1-2500:1 (preferably 100:1-2000:1 or 100:1-1000:1).

[0022] 14. The method according to any of the preceding or following aspects, wherein the operating conditions of the steam cracking include: reaction temperature 750-900°C, reaction pressure 0.1-0.5 MPaG, water-oil mass ratio 0.2-0.6.

[0023] 15. The method according to any of the preceding or following aspects, further comprising the following steps:

[0024] Separating the conversion product to obtain a separation stream mainly composed of C2-C6 normal alkanes (e.g., accounting for more than 80 wt%, more than 90 wt%, or more than 95 wt% of the total amount), and

[0025] The separated stream is steam cracked to obtain a cracking product comprising ethylene.

[0026] 16. The method according to any preceding or following aspect, wherein the weight ratio of the separation stream to the hydrocarbon stream is 0.4-0.9:1 (preferably 0.5-0.8:1).

[0027] 17. The method according to any of the preceding or following aspects, further comprising the following steps:

[0028] Separating the conversion product to obtain a normal stream mainly composed of C4-C6 normal alkanes (e.g., accounting for more than 80 wt%, more than 90 wt%, or more than 95 wt% of the total amount) and / or a low-carbon stream mainly composed of C2-C3 hydrocarbons (e.g., accounting for more than 90 wt% or more than 95 wt% of the total amount), and

[0029] The normal stream and / or the low carbon stream is steam cracked to obtain a cracking product comprising ethylene.

[0030] 18. A system for converting isoparaffins, comprising the following units:

[0031] 1) a hydrocarbon stream providing unit, which is configured to provide a hydrocarbon stream containing C5-C6 isoparaffins,

[0032] 2) a hydrocarbon stream conversion unit, which is configured to convert at least a portion (e.g., more than 30 wt%, more than 40 wt%, more than 50 wt%, more than 60 wt%, more than 70 wt%, more than 80 wt% or more than 90 wt%) of the C5-C6 isoparaffins in the presence of a molecular sieve with shape-selective catalytic performance and hydrogen to obtain a conversion product comprising C2-C3 hydrocarbons and C4-C6 normal alkanes (preferably C5-C6 normal alkanes), and

[0033] 3) An optional steam cracking unit configured to steam crack the conversion product to obtain a cracking product comprising ethylene.

[0034] Technical Effects

[0035] Compared with the prior art, the method and system provided by the present invention can achieve one of the following technical effects or a combination of all or part of them:

[0036] 1. When C5-C6 isoalkanes are used directly as ethylene feedstock, the yields of ethylene and trienes are relatively low. Through hydrogenation conversion, the ratio of C2-C3 low-carbon alkanes and C4-C6 normal alkanes in the hydrogenation products can be flexibly adjusted. According to the two different reaction pathways of C5-C6 isoalkanes, by adjusting the acid strength of the catalyst acid center, the two different reaction pathways of cracking and normalization can be flexibly adjusted. If the hydrogen cost is low or the hydrogen surplus is high, more C2-C3 low-carbon alkanes can be produced, so that the yield of the target ethylene product is greatly improved; if the hydrogen cost is high or the hydrogen surplus is low, more C4-C6 normal alkanes can be produced, and the quality of ethylene feedstock can be improved under the condition of lower hydrogen consumption.

[0037] 2. Flexible adjustment of the hydrocarbon structure composition of ethylene feedstock can maximize the operational flexibility of the ethylene plant, including flexible adjustment of the yields of the main target products of the ethylene plant, ethylene, propylene, butadiene and aromatics. The product structure can be adjusted according to changes in market demand to improve the market competitiveness of the ethylene plant. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 The figure is a process flow diagram of the process method of the present invention.

[0039] exist Figure 1 In the figure, 1-hydrocarbon stream, 2-hydrogen, 3-hydrogenation reaction zone, 4-hydrogenation reaction zone effluent, 5-high-pressure separator, 6-gas phase stream hydrogen-rich gas, 7-liquid phase stream. DETAILED DESCRIPTION

[0040] The specific embodiments of the present invention are described in detail below, but it should be pointed out that the protection scope of the present invention is not limited by these specific embodiments, but is determined by the claims in the appendix.

[0041] All publications, patent applications, patents and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings conventionally understood by those skilled in the art. In the event of a conflict, the definitions in this specification shall prevail.

[0042] When this specification uses the prefix "well-known to those skilled in the art", "prior art" or similar terms to introduce materials, substances, methods, steps, devices or components, etc., the objects introduced by the prefix cover those commonly used in the art when this application is filed, but also include those that are not commonly used at present but will become recognized in the art as being suitable for similar purposes.

[0043] In the context of the present invention, all numerical values ​​for parameters (eg amounts or conditions) are to be understood as being modified in all instances by the term "about", regardless of whether "about" actually appears before the numerical value.

[0044] In the context of the present invention, unless otherwise specified, each device used in the present invention may use a structure conventionally selected in the art without any particular limitation.

[0045] In the context of the present invention, the measurement method of the initial boiling point and the final boiling point is in accordance with the ASTM D86 measurement method.

[0046] In the context of the present invention, the term "C2-C6 normal alkane" refers to a normal alkane having a carbon number of from 2 to 6. It should be particularly clarified that, although there is no distinction between normal alkanes and isoalkanes for alkanes having a carbon number of from 2 to 3, for the sake of convenience of description, alkanes having a carbon number of from 2 to 3 are also regarded as normal alkanes. In addition, unless otherwise specified, the present invention may refer to any one or more of the normal alkanes having a carbon number of from 2 to 6, or may refer to all normal alkanes having a carbon number of from 2 to 6.

[0047] In the context of the present invention, cyclic hydrocarbons refer to hydrocarbons having a ring structure in their molecular structure, such as cycloalkanes and aromatic hydrocarbons.

[0048] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this specification are based on weight and pressure is gauge pressure.

[0049] In the context of the present invention, any two or more embodiments or aspects of the present invention may be arbitrarily combined, and the technical solutions thus formed belong to part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0050] According to one embodiment of the present application, it relates to a method for converting isoparaffins that can flexibly adjust the composition of the conversion product. According to the present invention, the weight ratio of C2-C3 hydrocarbons to C4-C6 normal alkanes in the conversion product can be flexibly adjusted within the range of 0.5:1-8:1 (preferably 0.9:1-5:1) by adjusting the catalyst molecular sieve type, the strength of the acidic center and the process parameters, thereby obtaining ethylene feedstocks of different hydrocarbon components. For conversion products with a higher content of C2-C3 hydrocarbons, the normal hydrocarbon content is higher, but the conversion process requires more hydrogen consumption; for conversion products with a higher content of C4-C6 normal alkanes, the hydrogen consumption is lower during the reaction, and the quality of the ethylene feedstock can also be improved. Here, from the perspective of achieving a more excellent technical effect of the present invention, the C4-C6 normal alkanes are more preferably C5-C6 normal alkanes.

[0051] According to one embodiment of the present application, the method includes the step of providing a hydrocarbon stream containing C5-C6 isoparaffins. According to the present invention, the hydrocarbon stream can be manufactured by any method known in the art, as long as it meets the requirements of the present invention for the hydrocarbon stream. As the manufacturing method of the hydrocarbon stream, for example, hydrocracking, catalytic cracking or atmospheric and vacuum distillation can be cited. Preferably, the initial boiling point of the hydrocarbon stream is 10-30°C (preferably 15-25°C), and the final boiling point is 50-100°C (preferably 55-70°C), and more preferably, the hydrocarbon stream is a light naphtha component obtained by hydrocracking a hydrocarbon oil feedstock.

[0052] According to one embodiment of the present application, in order to achieve the technical effect of the present invention, the content of the C5-C6 isoparaffins in the hydrocarbon stream is generally 50wt% or more (preferably 60-90wt%, more preferably 70-80wt%), based on the total weight of the hydrocarbon stream as 100wt%. According to the present invention, the conversion effect of isoparaffins in the hydrocarbon stream is affected by the type of catalyst and process conditions, as well as the molecular composition of the raw material, that is, the raw material must contain a relatively high amount of isoparaffins. If the isoparaffin content in the raw material is low, relative to the normal alkane content in the raw material, the normal alkane content in the conversion product is limited, and the target product is limited when used as an ethylene raw material; if the isoparaffin content in the raw material is high, although the normal alkane content in the conversion product can be greatly increased after conversion, it is difficult to obtain the raw material with a high isoparaffin content, and it is difficult to obtain it directly by conventional separation methods.

[0053] According to one embodiment of the present application, the C 7+There is no particular restriction on the content of hydrocarbons, but in order to make the technical effect of the present invention more excellent, the C 7+ The content of hydrocarbon is generally 0-10wt% (preferably 0.5-5wt%), based on the total weight of the hydrocarbon stream being 100wt%. The inventors of the present invention have found that for the hydroconversion catalyst of the present invention, since its molecular sieve has a relatively special pore structure, it is difficult for the macromolecular isoparaffins and cyclic hydrocarbons in the reactants to enter the catalyst pores for conversion (for example, the conversion rate is generally less than 10%). Therefore, too high C 7+ The hydrocarbon content will affect the conversion effect of the hydrocarbon stream of the present invention, which is not beneficial to the present invention.

[0054] According to one embodiment of the present application, there is no particular restriction on the content of C5-C6 normal alkanes in the hydrocarbon stream, but in order to make the technical effect of the present invention more excellent, the content of C5-C6 normal alkanes in the hydrocarbon stream is generally 10-30wt% (preferably 15-25wt%), based on the total weight of the hydrocarbon stream as 100wt%. The inventors of the present invention have found that since there are two reaction pathways of normalization and cracking reaction in the hydrogenation conversion process, the content of normal alkanes in the hydrocarbon stream has little effect on the cracking reaction, but will affect the normalization reaction. Excessive normal hydrocarbon content will inhibit the normalization reaction. At the same time, a higher ethylene product yield can be obtained when a raw material with a higher normal hydrocarbon content is directly used as an ethylene raw material, and the extent of improvement in the quality of the hydrocarbon stream after hydrogenation conversion is limited.

[0055] According to one embodiment of the present application, there is no particular restriction on the content of C4-hydrocarbon in the hydrocarbon stream, but in order to make the technical effect of the present invention more excellent, the content of C4-hydrocarbon in the hydrocarbon stream is generally 0-10wt% (preferably 2-5wt%), based on the total weight of the hydrocarbon stream as 100wt%. The inventors of the present invention have found that the physical properties of C4-hydrocarbon and C5-C6 hydrocarbon are quite different, especially the boiling point is quite different, which also increases the difficulty of mixing the two streams. In addition, the inventors of the present invention have found that the energy consumed by the conversion of C4-hydrocarbon is much higher than that of C5-C6 isoparaffins, and the reaction performance of C4 hydrocarbon and C5-C6 isoparaffins is poor when mixed and processed (for example, the conversion rate is generally less than 20%), so the excessively high content of C4 hydrocarbon will affect the conversion effect of C5-C6 isoparaffins, which is not conducive to the present invention.

[0056] According to one embodiment of the present application, there is no particular restriction on the content of cyclic hydrocarbons in the hydrocarbon stream, but in order to make the technical effect of the present invention more excellent, the content of cyclic hydrocarbons in the hydrocarbon stream is generally 1-10wt% (preferably 2-5wt%), based on the total weight of the hydrocarbon stream as 100wt%. The inventors of the present invention have found that as the carbon number of cyclic hydrocarbons increases, their molecular diameters also gradually increase, and large molecular cyclic hydrocarbons are difficult to enter the catalyst pores for reaction, and cyclic hydrocarbons that have not been hydrogenated and converted enter the ethylene unit, which will affect the yield of the target product of the ethylene unit, which is not conducive to the present invention.

[0057] According to one embodiment of the present application, at least a portion of the C5-C6 isoparaffins is subjected to a conversion reaction in the presence of a molecular sieve and hydrogen to obtain a conversion product comprising C2-C3 hydrocarbons and C4-C6 normal alkanes. Here, the so-called at least a portion, for example, accounts for more than 30wt%, more than 40wt%, more than 50wt%, more than 60wt%, more than 70wt%, more than 80wt% or more than 90wt% of the total amount. According to the present invention, there is no particular limitation on the conversion rate of C5-C6 isoparaffins. Therefore, C5-C6 isoparaffins can achieve the conversion rate (single-pass conversion rate) after a single conversion reaction, or can achieve the conversion rate after multiple recycling (for example, the unreacted C5-C6 isoparaffins are separated from the conversion product and then subjected to the conversion reaction).

[0058] According to one embodiment of the present application, the conversion reaction can be a hydrogenation normalization reaction to obtain a conversion product with C4-C6 normal alkanes as the main product, or a hydrocracking reaction to obtain a conversion product with C2-C3 hydrocarbons as the main product. The inventors of the present invention have found through research that there are two main reaction pathways for C5 and C6 isoalkanes during the hydrogenation conversion process, one is a cracking reaction to convert and generate C2-C3 hydrocarbons, and the other is a normalization reaction to generate C4-C6 normal alkanes. Generally, these two reactions occur simultaneously, but by adjusting the molecular sieve and the acid strength of the acid center, the strengthening of different reaction processes can be achieved. The strong acid center is conducive to the occurrence of the cracking reaction, while the medium-strong acid center is conducive to the occurrence of the normalization reaction. Based on this reaction principle, the generation ratio of C2-C3 hydrocarbons and C4-C6 normal alkanes in the conversion product can be flexibly adjusted. The inventors of the present invention have also found through research that the content of isoalkanes in the raw materials also has a direct impact on the conversion process. For the cracking reaction, although there is no restriction on whether the reactant is normal alkane or isoalkanes, the higher the content of isoalkanes in the raw materials, the greater the probability of cracking reaction, and the more obvious the improvement in the quality of the conversion product; while for the normalization reaction, the reactants are only isoalkanes, and the normalization reaction is affected by chemical equilibrium. The higher the content of isoalkanes, the more conducive it is for the conversion reaction to proceed in the normalization direction.

[0059] According to one embodiment of the present application, the reaction conditions of the conversion reaction include: a reaction pressure of 0.5-10.0 MPaG (preferably 2.0-8.0 MPaG or 2.0-5.0 MPaG), a reaction temperature of 250-500°C (preferably 350-450°C), a liquid hourly volume space velocity of 0.1-15.0 h -1 (Preferably 0.5-5.0h -1 ), the hydrogen to oil volume ratio is 10:1-2500:1 (preferably 100:1-2000:1 or 100:1-1000:1). The inventors of the present invention have found that, compared with the hydrocarbon stream conversion reaction of the prior art (such as the conversion reaction of C4 hydrocarbon stream), the reaction conditions of the conversion reaction of the present invention are milder, especially the reaction temperature is lower, such as generally 10-50°C lower. The inventors of the present invention have also found that at this lower reaction temperature, C5-C6 isoparaffins still show a higher conversion rate, such as C5-C6 isoparaffins can show a single-pass conversion rate of more than 40wt%, more than 50wt%, more than 60wt%, more than 70wt%, more than 80wt% or more than 90wt% under the reaction conditions of the present invention. In contrast, the conversion of hydrocarbon streams must first undergo a dehydrogenation reaction, that is, the dehydrogenation of alkanes to olefins. The smaller the molecule, the stronger the intermolecular force, and the greater the difficulty of dehydrogenation. Metals with strong dehydrogenation activity (such as precious metals such as Pt) are required. At the same time, affected by the molecular residence time, small molecular hydrocarbons have a shorter residence time in the catalyst pores. Therefore, the use of conventional metals to convert C4 hydrocarbons requires a higher reaction temperature (such as 20-30°C higher) than the present invention to achieve this process. In addition, for C 7+ For the conversion of components, for the hydrogenation conversion catalyst of the present invention, since its molecular sieve has a relatively special pore structure, it is difficult for the macromolecular isoalkanes and cyclic hydrocarbons in the reactants to enter the catalyst pores for conversion (for example, the conversion rate is generally less than 10%). Therefore, too high C 7+ The hydrocarbon content will affect the efficiency of the conversion of the hydrocarbon stream of the present invention.

[0060] According to one embodiment of the present application, the conversion reaction is carried out in the presence of a catalyst, and the catalyst comprises a molecular sieve and an active metal component.

[0061] According to one embodiment of the present application, the molecular sieve is a molecular sieve with shape-selective catalytic performance, preferably selected from one or more of mordenite, ZSM molecular sieve, SAPO molecular sieve and EU-1 molecular sieve, more preferably selected from one or more of mordenite and ZSM molecular sieve, particularly preferably selected from one or more of mordenite, ZSM-5 molecular sieve, ZSM-11 molecular sieve, ZSM-12 molecular sieve, ZSM-22 molecular sieve, ZSM-23 molecular sieve, ZSM-35 molecular sieve, Beta molecular sieve and ZSM-38 molecular sieve, especially selected from one or more of mordenite and ZSM-5 molecular sieve. Here, based on the weight of the catalyst, the content of the molecular sieve is 30-80wt% (preferably 40-70wt%).

[0062] The inventors of the present invention have found that there are two main reaction pathways in the hydrogenation conversion process, one is the cracking reaction of converting to C2-C3 hydrocarbons, and the other is the normalization reaction of generating C4-C6 normal alkanes. Generally, these two reactions occur simultaneously, but by adjusting the molecular sieve and the acid strength of the acid center, the different reaction processes can be strengthened. The strong acid center is conducive to the occurrence of the cracking reaction, while the medium-strong acid center is conducive to the occurrence of the normalization reaction. For example, mordenite contains more medium-strong acids, and its normalization reaction is more; while ZSM-5 molecular sieve contains more strong acids, and its cracking reaction is more. According to the present invention, by changing the weight ratio of the mordenite to the ZSM-5 molecular sieve between 0-100:100-0 (preferably 10-50:50-10), the weight ratio of C2-C3 hydrocarbons to C4-C6 normal alkanes in the conversion product can be flexibly adjusted.

[0063] According to one embodiment of the present application, the active metal component is at least one of the metal, metal oxide, and metal sulfide of the active metal component; the active metal is selected from one or more of the metals of Group VIB and the non-noble metals of Group VIII, the metals of Group VIB are preferably selected from one or more of molybdenum and tungsten (particularly preferably molybdenum), and the non-noble metals of Group VIII are preferably selected from one or more of cobalt and nickel (particularly preferably nickel). Here, based on the weight of the catalyst, the content of the metal of Group VIB (calculated as oxide) is 5.0-30.0wt% (10.0-20.0wt%), and the content of the non-noble metal of Group VIII (calculated as oxide) is 0.5-15.0wt% (preferably 3.0-10.0wt%).

[0064] According to one embodiment of the present application, the catalyst further comprises a binder. The type of the binder can be conventionally selected in the art, including but not limited to aluminum oxide and silicon oxide, wherein aluminum oxide is preferred. Here, based on the weight of the catalyst, the content of the binder is 5-65wt% (preferably 10-35wt%).

[0065] According to one embodiment of the present application, the specific surface area of ​​the catalyst is 200-400m 2 / g, and the pore volume is 0.25-0.45mL / g.

[0066] According to one embodiment of the present application, the preparation method of the catalyst can be prepared according to conventional methods in the art. The preparation method includes the preparation of the carrier and the loading of the active metal component, wherein the preparation process of the carrier is as follows: the molecular sieve and the binder are mechanically mixed, formed, and then dried and calcined to prepare a catalyst carrier. Conventional conditions can be used for drying and calcining the carrier. The drying condition is: drying at 100°C-150°C for 1-12 hours. The calcination condition is: calcining at 450°C-550°C for 2.5-6.0 hours.

[0067] According to one embodiment of the present application, in the preparation method of the catalyst, the method for loading the active metal component is a conventional method, such as a kneading method, an impregnation method, etc., preferably an impregnation method. The impregnation method can be a saturated impregnation method, an excess impregnation method or a complex impregnation method, that is, the catalyst carrier is impregnated with a solution containing the required active metal component, and then dried and calcined to obtain the first catalyst. The drying conditions are: drying at 100°C-150°C for 1-12 hours. The calcination conditions are: calcining at 450°C-550°C for 2.5-6.0 hours.

[0068] According to one embodiment of the present application, from the perspective of achieving a more excellent technical effect of the present invention, the content of C7+ hydrocarbons in the conversion product is not higher than 5wt% (preferably not higher than 1wt%), the content of C5-C6 isoparaffins is 0-50wt% (preferably 10-40wt%), the content of C2-C6 normal paraffins is 40-90wt% (preferably 50-80wt%), and the content of cyclic hydrocarbons is not higher than 3wt% (preferably not higher than 1wt%), based on the total weight of the conversion product as 100wt%.

[0069] According to one embodiment of the present application, the method further comprises the following steps: separating the conversion product to obtain a separation stream mainly composed of C2-C6 normal alkanes (e.g., accounting for more than 80wt%, more than 90wt% or more than 95wt% of the total amount). According to the specific situation of the conversion rate, unreacted C5-C6 isoparaffins may also be obtained through the separation. The unreacted C5-C6 isoparaffins may be used as a circulating material to continue the conversion reaction together with the raw hydrocarbon stream, thereby converting a higher proportion of C5-C6 isoparaffins into C2-C6 normal alkanes.

[0070] According to one embodiment of the present application, the weight ratio of the separation stream to the hydrocarbon stream is 0.4-0.9:1 (preferably 0.5-0.8:1).

[0071] According to this embodiment of the present invention, the method further comprises the following steps: separating the conversion product to obtain a normal stream mainly composed of C4-C6 normal alkanes (e.g., accounting for more than 80wt%, more than 90wt% or more than 95wt% of the total amount) and / or a low-carbon stream mainly composed of C2-C3 hydrocarbons (e.g., accounting for more than 90wt% or more than 95wt% of the total amount). According to the specific circumstances of the conversion rate, unreacted C5-C6 isoparaffins may also be obtained through the separation. The unreacted C5-C6 isoparaffins may be used as a circulating material to continue the conversion reaction with the raw hydrocarbon stream, thereby converting a higher proportion of C5-C6 isoparaffins into C2-C6 normal alkanes.

[0072] According to one embodiment of the present application, the conversion product, the separation stream, the normal stream or the low-carbon stream shows high chemical activity compared with the hydrocarbon stream, and can therefore be advantageously used in chemical treatments such as steam cracking, alkane degassing, hydrocracking, etc. to obtain high value-added chemicals, preferably used in steam cracking to produce ethylene.

[0073] According to one embodiment of the present application, the conversion product, the separation stream, the normal stream or the low-carbon stream are steam cracked to obtain a cracking product containing ethylene. According to the present invention, the conversion product, the separation stream, the normal stream or the low-carbon stream is an ideal ethylene cracking feedstock, and the ethylene yield when using these streams is generally above 30wt%, thereby finding a high-value utilization method for the low-value-added hydrocarbon stream in the prior art.

[0074] According to one embodiment of the present application, the operating conditions of the steam cracking include: reaction temperature 750-900° C., reaction pressure 0.1-0.5 MPaG, and water-to-oil mass ratio 0.2-0.6.

[0075] According to one embodiment of the present application, there is also a system for converting isoparaffins, which includes a hydrocarbon stream providing unit, a hydrocarbon stream conversion unit, and an optional steam cracking unit. According to the present invention, the system is specifically configured to implement the method described in the foregoing text of this specification. Therefore, except for the contents clearly defined in this paragraph, any other contents or matters not clearly defined can be directly referred to the contents or matters described in the foregoing text of this specification for the method, and there is no special limitation.

[0076] The present invention is further described below in conjunction with the accompanying drawings, but the present invention is not limited thereto.

[0077] according to Figure 1 The hydrocarbon stream 1 is mixed with hydrogen 2 and enters the hydroconversion reaction zone 3. The effluent 4 of the hydroconversion reaction zone enters the high-pressure separator 5. The separated gaseous stream hydrogen-rich gas 6 is recycled, and the liquid stream is used as an ethylene feedstock.

[0078] Example

[0079] The present invention is further described in detail below using examples and comparative examples, but the present invention is not limited to these examples.

[0080] In the following examples and comparative examples, the calculation method of ethylene yield is the mass percentage of ethylene output to the feed amount of ethylene unit, and the ton of oil processing benefit refers to the income obtained from processing 1 ton of raw materials, and the calculation method is (ethylene product price - raw material and hydrogen price - processing energy consumption) / processing amount. The benchmark of ton of oil processing benefit is that the raw materials are directly used as ethylene raw materials without hydrogenation conversion.

[0081] In the following examples and comparative examples, each hydroconversion catalyst is represented by Cat-A, Cat-B, Cat-C plus a number, such as Cat-A1, Cat-A2, Cat-A3, etc. The hydroconversion catalyst is prepared by a conventional active metal saturation impregnation method, and the physicochemical properties of the obtained catalyst are shown in Table 1.

[0082] The preparation method of Cat-A catalyst is:

[0083] (1) Mordenite with a SiO2 / Al2O3 molar ratio of 15 was selected and mechanically mixed with a binder, molded, dried at 120°C for 10 hours, and calcined at 500°C for 4 hours to prepare a catalyst carrier.

[0084] (2) The catalyst carrier obtained in step (1) is impregnated with the active component, dried at 120°C for 10 hours, and calcined at 500°C for 4 hours to prepare a hydrogenation conversion catalyst.

[0085] The preparation method of Cat-B catalyst is:

[0086] (1) A ZSM-5 molecular sieve with a SiO2 / Al2O3 molar ratio of 10 was selected and mechanically mixed with a binder, molded, dried at 120°C for 10 hours, and calcined at 500°C for 4 hours to prepare a catalyst carrier.

[0087] (2) The catalyst carrier obtained in step (1) is impregnated with the active component, dried at 120°C for 10 hours, and calcined at 500°C for 4 hours to prepare a hydrogenation conversion catalyst.

[0088] The preparation method of Cat-C catalyst is:

[0089] (1) A ZSM-35 molecular sieve having a SiO2 / Al2O3 molar ratio of 20 was selected and mechanically mixed with a binder, molded, dried at 120°C for 10 hours, and calcined at 500°C for 4 hours to prepare a catalyst carrier.

[0090] (2) The catalyst carrier obtained in step (1) is impregnated with the active component, dried at 120°C for 10 hours, and calcined at 500°C for 4 hours to prepare a hydrogenation conversion catalyst.

[0091] The preparation method of Cat-D catalyst is:

[0092] (1) SAPO-34 molecular sieve with a SiO2 / Al2O3 molar ratio of 0.5 was selected and mechanically mixed with a binder, molded, dried at 120°C for 10 hours, and calcined at 500°C for 4 hours to prepare a catalyst carrier.

[0093] (2) The catalyst carrier obtained in step (1) is impregnated with the active component, dried at 120°C for 10 hours, and calcined at 500°C for 4 hours to prepare a hydrogenation conversion catalyst.

[0094] The preparation method of Cat-E catalyst is:

[0095] (1) Selecting a Y molecular sieve with a SiO2 / Al2O3 molar ratio of 15 and mechanically mixing it with a binder, forming it, drying it at 120°C for 10 hours, and calcining it at 500°C for 4 hours to prepare a catalyst carrier.

[0096] (2) The catalyst carrier obtained in step (1) is impregnated with the active component, dried at 120°C for 10 hours, and calcined at 500°C for 4 hours to prepare a hydrogenation conversion catalyst.

[0097] The properties of the raw materials are shown in Table 2. Among them, the raw material 5 needs to be obtained by adsorption separation or distillation of an isoparaffin-containing raw material.

[0098] Table 1

[0099]

[0100] Table 1

[0101]

[0102] Table 2

[0103] raw material Raw material 1 Raw material 2 Raw material 3 Raw material 4 Raw material 5 Raw material 6 <![CDATA[C4 isoparaffin content, wt%]]> 1 2 0.5 1 0.4 80 <![CDATA[n - paraffin content in C4, wt%]]> 2 3 1.5 2 0.6 11 <![CDATA[Content of C5-C6 normal paraffin, wt%]]> 16 28 10 42 3 2 <![CDATA[C5-C6 isoparaffin content, wt%]]> 78 65 85 50 95 7 <![CDATA[C 7+ Hydrocarbon and cyclic hydrocarbon content, wt%]]> 3 2 3 5 1 0 Initial distillation point, ℃ 24 25 22 25 23 16 Final distillation point, ℃ 64 66 63 67 62 45

[0104] Example 1

[0105] The conversion method of isoparaffins which can flexibly adjust the composition of the conversion products adopts the following method: Figure 1 Process, including:

[0106] (1) Raw material 1 is mixed with hydrogen and sequentially enters the hydroconversion reaction zone; the hydroconversion reaction zone is loaded with hydroconversion catalyst Cat-A1;

[0107] (2) Step (1) The gas-liquid separation of the reaction effluent from the hydroconversion reaction zone is into hydrogen-rich gas and liquid phase stream, the hydrogen-rich gas is recycled, and the liquid phase stream is directly used as ethylene feedstock. The process conditions and conversion results in this example are shown in Table 3.

[0108] In this example, about 33 wt% of the total C5-C6 isoparaffins are converted into C2-C6 normal paraffins, and the weight ratio of C2-C3 hydrocarbons to C4-C6 normal paraffins in the reaction effluent is 0.9: 1. The weight ratio of the liquid phase stream to the feedstock 1 is 0.63: 1.

[0109] Example 2

[0110] The conversion method of isoparaffins which can flexibly adjust the composition of the conversion products adopts the following method: Figure 1 Process, including:

[0111] (1) Raw material 1 is mixed with hydrogen and sequentially enters the hydroconversion reaction zone; the hydroconversion reaction zone is loaded with hydroconversion catalyst Cat-A2;

[0112] (2) Step (1) The gas-liquid separation of the reaction effluent from the hydroconversion reaction zone is into hydrogen-rich gas and liquid phase stream, the hydrogen-rich gas is recycled, and the liquid phase stream is directly used as ethylene feedstock. The process conditions and conversion results in this example are shown in Table 3.

[0113] In this example, about 37 wt% of the total C5-C6 isoparaffins are converted into C2-C6 normal paraffins, and the weight ratio of C2-C3 hydrocarbons to C4-C6 normal paraffins in the reaction effluent is 1.4: 1. The weight ratio of the liquid phase stream to the feedstock 1 is 0.53:1.

[0114] Example 3

[0115] The conversion method of isoparaffins which can flexibly adjust the composition of the conversion products adopts the following method: Figure 1 Process, including:

[0116] (1) Raw material 1 is mixed with hydrogen and sequentially enters the hydroconversion reaction zone; the hydroconversion reaction zone is loaded with hydroconversion catalyst Cat-A3;

[0117] (2) Step (1) The gas-liquid separation of the reaction effluent from the hydroconversion reaction zone is into hydrogen-rich gas and liquid phase stream, the hydrogen-rich gas is recycled, and the liquid phase stream is directly used as ethylene feedstock. The process conditions and conversion results in this example are shown in Table 3.

[0118] In this example, about 42 wt% of the total C5-C6 isoparaffins are converted into C2-C6 normal paraffins, and the weight ratio of C2-C3 hydrocarbons to C4-C6 normal paraffins in the reaction effluent is 2.1: 1. The weight ratio of the liquid phase stream to the feedstock 1 is 0.35:1.

[0119] Example 4

[0120] The conversion method of isoparaffins which can flexibly adjust the composition of the conversion products adopts the following method: Figure 1 Process, including:

[0121] (1) Raw material 1 is mixed with hydrogen and sequentially enters the hydroconversion reaction zone; the hydroconversion reaction zone is loaded with hydroconversion catalyst Cat-B1;

[0122] (2) Step (1) The gas-liquid separation of the reaction effluent from the hydroconversion reaction zone is into hydrogen-rich gas and liquid phase stream, the hydrogen-rich gas is recycled, and the liquid phase stream is directly used as ethylene feedstock. The process conditions and conversion results in this example are shown in Table 3.

[0123] In this example, about 62 wt% of the total C5-C6 isoparaffins are converted into C2-C6 normal paraffins, and the weight ratio of C2-C3 hydrocarbons to C4-C6 normal paraffins in the reaction effluent is 5: 1. The weight ratio of the liquid phase stream to the feedstock 1 is 0.07: 1.

[0124] Example 5

[0125] The conversion method of isoparaffins which can flexibly adjust the composition of the conversion products adopts the following method: Figure 1 Process, including:

[0126] (1) Raw material 1 is mixed with hydrogen and sequentially enters the hydroconversion reaction zone; the hydroconversion reaction zone is loaded with hydroconversion catalyst Cat-B2;

[0127] (2) Step (1) The gas-liquid separation of the reaction effluent from the hydroconversion reaction zone is into hydrogen-rich gas and liquid phase stream, the hydrogen-rich gas is recycled, and the liquid phase stream is directly used as ethylene feedstock. The process conditions and conversion results in this example are shown in Table 3.

[0128] In this example, about 57 wt% of the total C5-C6 isoparaffins are converted into C2-C6 normal paraffins, and the weight ratio of C2-C3 hydrocarbons to C4-C6 normal paraffins in the reaction effluent is 4.4: 1. The weight ratio of the liquid phase stream to the feedstock 1 is 0.13: 1.

[0129] Example 6

[0130] The conversion method of isoparaffins which can flexibly adjust the composition of the conversion products adopts the following method: Figure 1 Process, including:

[0131] (1) Raw material 1 is mixed with hydrogen and sequentially enters the hydroconversion reaction zone; the hydroconversion reaction zone is loaded with hydroconversion catalyst Cat-B3;

[0132] (2) Step (1) The gas-liquid separation of the reaction effluent from the hydroconversion reaction zone is into hydrogen-rich gas and liquid phase stream, the hydrogen-rich gas is recycled, and the liquid phase stream is directly used as ethylene feedstock. The process conditions and conversion results in this example are shown in Table 3.

[0133] In this example, about 52 wt% of the total C5-C6 isoparaffins are converted into C2-C6 normal paraffins, and the weight ratio of C2-C3 hydrocarbons to C4-C6 normal paraffins in the reaction effluent is 3.9: 1. The weight ratio of the liquid phase stream to the feedstock 1 is 0.22: 1.

[0134] Example 7

[0135] The conversion method of isoparaffins which can flexibly adjust the composition of the conversion products adopts the following method: Figure 1 Process, including:

[0136] (1) Feedstock 1 and hydrogen are mixed and sequentially fed into the hydroconversion reaction zone; the hydroconversion reaction zone is sequentially loaded with hydroconversion catalysts Cat-B1 and Cat-A1 along the feedstock flow direction;

[0137] (2) Step (1) The gas-liquid separation of the reaction effluent from the hydroconversion reaction zone is into hydrogen-rich gas and liquid phase stream, the hydrogen-rich gas is recycled, and the liquid phase stream is directly used as ethylene feedstock. The process conditions and conversion results in this example are shown in Table 3.

[0138] In this example, about 48 wt% of the total C5-C6 isoparaffins are converted into C2-C6 normal paraffins, and the weight ratio of C2-C3 hydrocarbons to C4-C6 normal paraffins in the reaction effluent is 3.2: 1. The weight ratio of the liquid phase stream to the feedstock 1 is 0.28: 1.

[0139] Example 8

[0140] The conversion method of isoparaffins which can flexibly adjust the composition of the conversion products adopts the following method: Figure 1 Process, including:

[0141] (1) Feedstock 1 and hydrogen are mixed and sequentially fed into the hydroconversion reaction zone; the hydroconversion reaction zone is sequentially loaded with hydroconversion catalysts Cat-B1 and Cat-A1 along the feedstock flow direction;

[0142] (2) Step (1) The gas-liquid separation of the reaction effluent from the hydroconversion reaction zone is into hydrogen-rich gas and liquid phase stream, the hydrogen-rich gas is recycled, and the liquid phase stream is directly used as ethylene feedstock. The process conditions and conversion results in this example are shown in Table 3.

[0143] In this example, about 44 wt% of the total C5-C6 isoparaffins are converted into C2-C6 normal paraffins, and the weight ratio of C2-C3 hydrocarbons to C4-C6 normal paraffins in the reaction effluent is 2.3: 1. The weight ratio of the liquid phase stream to the feedstock 1 is 0.32: 1.

[0144] Example 9

[0145] The conversion method of isoparaffins which can flexibly adjust the composition of the conversion products adopts the following method: Figure 1 Process, including:

[0146] (1) Feedstock 1 and hydrogen are mixed and sequentially fed into the hydroconversion reaction zone; the hydroconversion reaction zone is sequentially loaded with hydroconversion catalysts Cat-B1 and Cat-A1 along the feedstock flow direction;

[0147] (2) Step (1) The gas-liquid separation of the reaction effluent from the hydroconversion reaction zone is into hydrogen-rich gas and liquid phase stream, the hydrogen-rich gas is recycled, and the liquid phase stream is directly used as ethylene feedstock. The process conditions and conversion results in this example are shown in Table 3.

[0148] In this example, about 40 wt% of the total C5-C6 isoparaffins are converted into C2-C6 normal paraffins, and the weight ratio of C2-C3 hydrocarbons to C4-C6 normal paraffins in the reaction effluent is 2.5: 1. The weight ratio of the liquid phase stream to the feedstock 1 is 0.29: 1.

[0149] Example 10

[0150] The conversion method of isoparaffins which can flexibly adjust the composition of the conversion products adopts the following method: Figure 1 Process, including:

[0151] (1) Feedstock 1 and hydrogen are mixed and sequentially fed into the hydroconversion reaction zone; the hydroconversion reaction zone is sequentially loaded with hydroconversion catalysts Cat-B1 and Cat-A1 along the feedstock flow direction;

[0152] (2) Step (1) The gas-liquid separation of the reaction effluent from the hydroconversion reaction zone is into hydrogen-rich gas and liquid phase stream, the hydrogen-rich gas is recycled, and the liquid phase stream is directly used as ethylene feedstock. The process conditions and conversion results in this example are shown in Table 3.

[0153] In this example, about 38 wt% of the total C5-C6 isoparaffins are converted into C2-C6 normal paraffins, and the weight ratio of C2-C3 hydrocarbons to C4-C6 normal paraffins in the reaction effluent is 1.8: 1. The weight ratio of the liquid phase stream to the feedstock 1 is 0.43: 1.

[0154] Embodiment 11

[0155] The conversion method of isoparaffins which can flexibly adjust the composition of the conversion products adopts the following method: Figure 1Process, including:

[0156] (1) Feedstock 1 and hydrogen are mixed and sequentially fed into the hydroconversion reaction zone; the hydroconversion reaction zone is sequentially loaded with hydroconversion catalysts Cat-B1 and Cat-A1 along the feedstock flow direction;

[0157] (2) Step (1) The gas-liquid separation of the reaction effluent from the hydroconversion reaction zone is into hydrogen-rich gas and liquid phase stream, the hydrogen-rich gas is recycled, and the liquid phase stream is directly used as ethylene feedstock. The process conditions and conversion results in this example are shown in Table 3.

[0158] In this example, about 36 wt% of the total C5-C6 isoparaffins are converted into C2-C6 normal paraffins, and the weight ratio of C2-C3 hydrocarbons to C4-C6 normal paraffins in the reaction effluent is 1.3: 1. The weight ratio of the liquid phase stream to the feedstock 1 is 0.54: 1.

[0159] Example 12

[0160] The conversion method of isoparaffins which can flexibly adjust the composition of the conversion products adopts the following method: Figure 1 Process, including:

[0161] (1) Raw material 2 is mixed with hydrogen and sequentially enters the hydroconversion reaction zone; the hydroconversion reaction zone is loaded with hydroconversion catalyst Cat-A1;

[0162] (2) Step (1) The gas-liquid separation of the reaction effluent from the hydroconversion reaction zone is into hydrogen-rich gas and liquid phase stream, the hydrogen-rich gas is recycled, and the liquid phase stream is directly used as ethylene feedstock. The process conditions and conversion results in this example are shown in Table 3.

[0163] In this example, about 42 wt% of the total C5-C6 isoparaffins are converted into C2-C6 normal paraffins, and the weight ratio of C2-C3 hydrocarbons to C4-C6 normal paraffins in the reaction effluent is 2.2: 1. The weight ratio of the liquid phase stream to the feedstock 1 is 0.34: 1.

[0164] Embodiment 13

[0165] The conversion method of isoparaffins which can flexibly adjust the composition of the conversion products adopts the following method: Figure 1 Process, including:

[0166] (1) The raw material 3 is mixed with hydrogen and sequentially enters the hydroconversion reaction zone; the hydroconversion reaction zone is loaded with the hydroconversion catalyst Cat-B1;

[0167] (2) Step (1) The gas-liquid separation of the reaction effluent from the hydroconversion reaction zone is into hydrogen-rich gas and liquid phase stream, the hydrogen-rich gas is recycled, and the liquid phase stream is directly used as ethylene feedstock. The process conditions and conversion results in this example are shown in Table 3.

[0168] In this example, about 56 wt% of the total C5-C6 isoparaffins are converted into C2-C6 normal paraffins, and the weight ratio of C2-C3 hydrocarbons to C4-C6 normal paraffins in the reaction effluent is 4.1: 1. The weight ratio of the liquid phase stream to the feedstock 1 is 0.15: 1.

[0169] Embodiment 14

[0170] The conversion method of isoparaffins which can flexibly adjust the composition of the conversion products adopts the following method: Figure 1 Process, including:

[0171] (1) Raw material 1 is mixed with hydrogen and sequentially enters the hydroconversion reaction zone; the hydroconversion reaction zone is loaded with hydroconversion catalyst Cat-A1;

[0172] (2) Step (1) The gas-liquid separation of the reaction effluent from the hydroconversion reaction zone is into hydrogen-rich gas and liquid phase stream, the hydrogen-rich gas is recycled, and the liquid phase stream is directly used as ethylene feedstock. The process conditions and conversion results in this example are shown in Table 3.

[0173] In this example, about 25 wt% of the total C5-C6 isoparaffins are converted into C2-C6 normal paraffins, and the weight ratio of C2-C3 hydrocarbons to C4-C6 normal paraffins in the reaction effluent is 0.7: 1. The weight ratio of the liquid phase stream to the feedstock 1 is 0.75: 1.

[0174] Embodiment 15

[0175] The conversion method of isoparaffins which can flexibly adjust the composition of the conversion products adopts the following method: Figure 1 Process, including:

[0176] (1) Raw material 1 is mixed with hydrogen and sequentially enters the hydroconversion reaction zone; the hydroconversion reaction zone is loaded with a hydroconversion catalyst Cat-C;

[0177] (2) Step (1) The gas-liquid separation of the reaction effluent from the hydroconversion reaction zone is into hydrogen-rich gas and liquid phase stream, the hydrogen-rich gas is recycled, and the liquid phase stream is directly used as ethylene feedstock. The process conditions and conversion results in this example are shown in Table 3.

[0178] In this example, about 28 wt% of the total C5-C6 isoparaffins are converted into C2-C6 normal paraffins, and the weight ratio of C2-C3 hydrocarbons to C4-C6 normal paraffins in the reaction effluent is 0.8: 1. The weight ratio of the liquid phase stream to the feedstock 1 is 0.70: 1.

[0179] Example 16

[0180] The conversion method of isoparaffins which can flexibly adjust the composition of the conversion products adopts the following method: Figure 1 Process, including:

[0181] (1) Raw material 1 is mixed with hydrogen and sequentially enters the hydroconversion reaction zone; the hydroconversion reaction zone is loaded with a hydroconversion catalyst Cat-D;

[0182] (2) Step (1) The gas-liquid separation of the reaction effluent from the hydroconversion reaction zone is into hydrogen-rich gas and liquid phase stream, the hydrogen-rich gas is recycled, and the liquid phase stream is directly used as ethylene feedstock. The process conditions and conversion results in this example are shown in Table 3.

[0183] In this example, about 26 wt% of the total C5-C6 isoparaffins are converted into C2-C6 normal paraffins, and the weight ratio of C2-C3 hydrocarbons to C4-C6 normal paraffins in the reaction effluent is 0.7: 1. The weight ratio of the liquid phase stream to the feedstock 1 is 0.74: 1.

[0184] Comparative Example 1

[0185] The transformation method used was Figure 1 Process, including:

[0186] (1) The raw material 4 is mixed with hydrogen and sequentially enters the hydroconversion reaction zone; the hydroconversion reaction zone is loaded with the hydroconversion catalyst Cat-A1;

[0187] (2) Step (1) The gas-liquid separation of the reaction effluent from the hydroconversion reaction zone is into hydrogen-rich gas and liquid phase stream, the hydrogen-rich gas is recycled, and the liquid phase stream is directly used as ethylene feedstock. The process conditions and conversion results in this example are shown in Table 3.

[0188] Comparative Example 2

[0189] The transformation method used was Figure 1 Process, including:

[0190] (1) The raw material 4 is mixed with hydrogen and sequentially enters the hydroconversion reaction zone; the hydroconversion reaction zone is loaded with the hydroconversion catalyst Cat-B1;

[0191] (2) Step (1) The gas-liquid separation of the reaction effluent from the hydroconversion reaction zone is into hydrogen-rich gas and liquid phase stream, the hydrogen-rich gas is recycled, and the liquid phase stream is directly used as ethylene feedstock. The process conditions and conversion results in this example are shown in Table 3.

[0192] Comparative Example 3

[0193] The transformation method used was Figure 1 Process, including:

[0194] (1) The raw material 5 is mixed with hydrogen and sequentially enters the hydroconversion reaction zone; the hydroconversion reaction zone is loaded with the hydroconversion catalyst Cat-A1;

[0195] (2) Step (1) The gas-liquid separation of the reaction effluent from the hydroconversion reaction zone is into hydrogen-rich gas and liquid phase stream, the hydrogen-rich gas is recycled, and the liquid phase stream is directly used as ethylene feedstock. The process conditions and conversion results in this example are shown in Table 3.

[0196] Comparative Example 4

[0197] The transformation method used was Figure 1 Process, including:

[0198] (1) The raw material 5 is mixed with hydrogen and sequentially enters the hydroconversion reaction zone; the hydroconversion reaction zone is loaded with the hydroconversion catalyst Cat-B1;

[0199] (2) Step (1) The gas-liquid separation of the reaction effluent from the hydroconversion reaction zone is into hydrogen-rich gas and liquid phase stream, the hydrogen-rich gas is recycled, and the liquid phase stream is directly used as ethylene feedstock. The process conditions and conversion results in this example are shown in Table 3.

[0200] Comparative Example 5

[0201] The transformation method used was Figure 1 Process, including:

[0202] (1) Raw material 1 is mixed with hydrogen and sequentially enters the hydroconversion reaction zone; the hydroconversion reaction zone is loaded with hydroconversion catalyst Cat-A4;

[0203] (2) Step (1) The gas-liquid separation of the reaction effluent from the hydroconversion reaction zone is into hydrogen-rich gas and liquid phase stream, the hydrogen-rich gas is recycled, and the liquid phase stream is directly used as ethylene feedstock. The process conditions and conversion results in this example are shown in Table 3.

[0204] Comparative Example 6

[0205] The transformation method used was Figure 1 Process, including:

[0206] (1) The raw material 6 is mixed with hydrogen and sequentially enters the hydroconversion reaction zone; the hydroconversion reaction zone is loaded with the hydroconversion catalyst Cat-A1;

[0207] (2) Step (1) The gas-liquid separation of the reaction effluent from the hydroconversion reaction zone is into hydrogen-rich gas and liquid phase stream, the hydrogen-rich gas is recycled, and the liquid phase stream is directly used as ethylene feedstock. The process conditions and conversion results in this example are shown in Table 3.

[0208] Comparative Example 7

[0209] The transformation method used was Figure 1 Process, including:

[0210] (1) Raw material 1 is mixed with hydrogen and sequentially enters the hydroconversion reaction zone; the hydroconversion reaction zone is loaded with a hydroconversion catalyst Cat-E;

[0211] (2) Step (1) The gas-liquid separation of the reaction effluent from the hydroconversion reaction zone is into hydrogen-rich gas and liquid phase stream, the hydrogen-rich gas is recycled, and the liquid phase stream is directly used as ethylene feedstock. The process conditions and conversion results in this example are shown in Table 3. Table 3 Conversion results

[0212] serial number Example 1 Example 2 Example 3 Hydrogenation conversion raw material Raw material 1 Raw material 1 Raw material 1 catalyst Cat-A1 Cat-A2 Cat-A3 Reaction temperature / ℃ 400 400 405 Reaction pressure / MPa 4 4 4 Hydrogen to oil volume ratio 600 500 600 <![CDATA[Space velocity per hour -1 > 1.2 0.8 1 <![CDATA[Content of C2-C6 normal paraffins in the product, wt%]]> 49 53 58 Steam cracking to produce ethylene Reaction temperature / ℃ 880 880 880 Reaction pressure / MPa 0.3 0.3 0.3 Water-oil mass ratio 0.4 0.4 0.4 Ethylene yield, wt% 32.8 33.2 35.4 Propylene yield, wt% 17.7 17.4 16.6 Butadiene yield, wt% 3.8 3.8 3.7 Processing benefit per ton of oil, Yuan / ton Baseline+190 Baseline +170 Baseline+160 serial number Example 4 Example 5 Example 6 Hydrogenation conversion raw material Raw material 1 Raw material 1 Raw material 1 catalyst Cat-B1 Cat-B2 Cat-B3 Reaction temperature / ℃ 420 410 410 Reaction pressure / MPa 4 4 4 Hydrogen to oil volume ratio 500 400 400 Volume space velocity / h-1 0.8 1 0.8 Product C2-C6 normal alkane content, wt% 78 73 68 Steam cracking to produce ethylene Reaction temperature / ℃ 880 880 880 Reaction pressure / MPa 0.3 0.3 0.3 Water-oil mass ratio 0.4 0.4 0.4 Ethylene yield, wt% 40.2 39.5 37.9 Propylene yield, wt% 13.5 13.8 14.5 Butadiene yield, wt% 3.3 3.4 3.6 Processing benefit per ton of oil, Yuan / ton Baseline+190 Baseline+180 Baseline+160

[0213] Table 3 Conversion results

[0214]

[0215]

[0216]

[0217] Table 3 Conversion results

[0218]

[0219] By comparison, it can be seen that the method of the present invention can achieve the selective conversion of isoalkanes, and can flexibly adjust the ratio of C2-C3 hydrocarbons to C4-C6 normal alkanes in the conversion products, thereby achieving flexible adjustment of the ethylene product structure and improving the product flexibility of the ethylene plant.

Claims

1. A method for converting isoparaffins, comprising the following steps: 1) providing a hydrocarbon stream containing C5-C6 isoparaffins, 2) subjecting at least a portion (e.g., more than 30 wt%, more than 40 wt%, more than 50 wt%, more than 60 wt%, more than 70 wt%, more than 80 wt% or more than 90 wt%) of the C5-C6 isoparaffins to a conversion reaction in the presence of a molecular sieve having shape-selective catalytic performance and hydrogen to obtain a conversion product comprising C2-C3 hydrocarbons and C4-C6 normal alkanes (preferably C5-C6 normal alkanes), and 3) Optionally steam cracking the conversion product to obtain a cracking product comprising ethylene.

2. The method of claim 1, wherein the weight ratio of the C2-C3 hydrocarbons to the C4-C6 normal alkanes (preferably the C5-C6 normal alkanes) in the conversion product is 0.5:1-8:1 (preferably 0.9:1-5:1).

3. The process of claim 1, wherein the hydrocarbon stream has an initial boiling point of 10-30°C (preferably 15-25°C) and a final boiling point of 50-100°C (preferably 55-70°C).

4. The method of claim 1, wherein the content of C7+ hydrocarbons in the hydrocarbon stream is 0-10wt% (preferably 0.5-5wt%), the content of C5-6 isoparaffins is 50wt% or more (preferably 60-90wt%, more preferably 70-80wt%), the content of C5-C6 normal paraffins is 10-30wt% (preferably 15-25wt%), the content of C4- hydrocarbons is 0-10wt% (preferably 2-5wt%), the content of cyclic hydrocarbons is 1-10wt% (preferably 2-5wt%). t%), based on the total weight of the hydrocarbon stream as 100wt%, and / or, the content of C7+ hydrocarbons in the conversion product is not higher than 5wt% (preferably not higher than 1wt%), the content of C5-C6 isoparaffins is 0-50wt% (preferably 10-40wt%), the content of C2-C6 normal paraffins is 40-90wt% (preferably 50-80wt%), and the content of cyclic hydrocarbons is not higher than 3wt% (preferably not higher than 1wt%), based on the total weight of the conversion product as 100wt%.

5. The method of claim 1, wherein the conversion reaction is carried out in the presence of a catalyst, and the catalyst comprises the molecular sieve and an active metal component.

6. The method of claim 5, wherein the molecular sieve is selected from one or more of mordenite, ZSM molecular sieve, SAPO molecular sieve and EU-1 molecular sieve, more preferably selected from one or more of mordenite and ZSM molecular sieve, particularly preferably selected from one or more of mordenite, ZSM-5 molecular sieve, ZSM-11 molecular sieve, ZSM-12 molecular sieve, ZSM-22 molecular sieve, ZSM-23 molecular sieve, ZSM-35 molecular sieve, Beta molecular sieve and ZSM-38 molecular sieve, in particular selected from one or more of mordenite and ZSM-5 molecular sieve, and particularly preferably the weight ratio of mordenite to ZSM-5 molecular sieve is 0-100:100-0 (preferably 10-50:50-10).

7. The method of claim 5, wherein the catalyst further comprises a binder (preferably alumina), and the content of the binder is 5-65 wt% (preferably 10-35 wt%) based on the weight of the catalyst.

8. The method of claim 5, wherein the active metal component is at least one of a metal, a metal oxide, and a metal sulfide of an active metal component; the active metal is selected from one or more of a VIB group metal and a VIII group non-noble metal, the VIB group metal is preferably selected from one or more of molybdenum and tungsten (molybdenum is particularly preferred), and the VIII group non-noble metal is preferably selected from one or more of cobalt and nickel (nickel is particularly preferred).

9. The method of claim 8, wherein the content of the Group VIB metal (calculated as oxide) is 5.0-30.0 wt% (preferably 10-20 wt%), and the content of the Group VIII non-noble metal (calculated as oxide) is 0.5-15.0 wt% (preferably 3-10 wt%), based on the weight of the catalyst.

10. The method of claim 5, wherein the molecular sieve content is 30-80 wt% (preferably 40-70 wt%) based on the weight of the catalyst.

11. The method of claim 1, wherein the reaction conditions of the conversion reaction include: The reaction pressure is 0.5-10.0MPaG (preferably 2.0-8.0MPaG or 2.0-5.0MPaG), the reaction temperature is 250-500℃ (preferably 350-450℃), and the liquid hourly volume space velocity is 0.1-15.0h -1 (Preferably 0.5-5.0h -1 ), the volume ratio of hydrogen to oil is 10:1-2500:1 (preferably 100:1-2000:1 or 100:1-1000:1).

12. The method of claim 1, further comprising the steps of: Optionally separating the conversion product to obtain a separated stream mainly composed of C2-C6 normal alkanes (e.g., accounting for more than 80 wt%, more than 90 wt%, or more than 95 wt% of the total amount), or separating the conversion product to obtain a normal stream mainly composed of C4-C6 normal alkanes (e.g., accounting for more than 80 wt%, more than 90 wt%, or more than 95 wt% of the total amount) and / or a low-carbon stream mainly composed of C2-C3 hydrocarbons (e.g., accounting for more than 90 wt% or more than 95 wt% of the total amount), and The conversion product, the separation stream, the normal stream or the low-carbon stream is steam cracked to obtain a cracking product comprising ethylene.

13. The process of claim 12, wherein the weight ratio of the separation stream to the hydrocarbon stream is 0.4-0.9:1 (preferably 0.5-0.8:1).

14. The method of claim 12, wherein the operating conditions of the steam cracking include: The reaction temperature is 750-900°C, the reaction pressure is 0.1-0.5MPaG, and the water-oil mass ratio is 0.2-0.

6.

15. A system for converting isoparaffins, comprising the following units: 1) a hydrocarbon stream providing unit, which is configured to provide a hydrocarbon stream containing C5-C6 isoparaffins, 2) a hydrocarbon stream conversion unit, which is configured to convert at least a portion (e.g., more than 30 wt%, more than 40 wt%, more than 50 wt%, more than 60 wt%, more than 70 wt%, more than 80 wt% or more than 90 wt%) of the C5-C6 isoparaffins in the presence of a molecular sieve having shape-selective catalytic performance and hydrogen to obtain a conversion product comprising C2-C3 hydrocarbons and C4-C6 normal alkanes (preferably C5-C6 normal alkanes), and 3) An optional steam cracking unit configured to steam crack the conversion product to obtain a cracking product comprising ethylene.

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