Method and device for producing 1-butene from mixed C4 raw material

Abstract

The invention provides a method and a device for producing 1-butene from a mixed C4 raw material. The method comprises the following steps: (1) carrying out hydroisomerization treatment on a mixed C4 raw material to obtain a C4 material I rich in 2-butene; (2) pretreating the C4 material I rich in 2-butene to respectively obtain a material II rich in isobutene, a material III rich in 1-butene and a heavy C4 material IV rich in 2-butene, recycling the material III rich in 1-butene to the step (1) to be mixed with the mixed C4 raw material, and carrying out hydroisomerization treatment; (3) carrying out isomerization treatment on the heavy C4 material IV rich in 2-butene to obtain a material V containing 1-butene; and (4) carrying out hydrofining treatment on the material V containing 1-butene to respectively obtain a 1-butene product and a material VI containing 2-butene. By using the method and the device provided by the invention, the isomerization rate of the mixed C4 raw material and the productivity of 1-butene can be improved, and the method and the device have relatively high industrial application value.

Description

Technical Field

[0001] The invention relates to the production of 1-butene, and in particular to a method and a device for producing 1-butene from mixed C4 raw materials. Background Art

[0002] 1-Butene is an α-olefin with active chemical properties. High-purity 1-butene is mainly used as a comonomer in the production of linear low-density polyethylene. In addition, other oligomerization products of 1-butene, such as dimer 1-octene and trimer dodecene, can replace 1-butene to synthesize better LLDPE and HDPE, and can also be used in large quantities in automobile and lubricant additives, synthetic detergents, surfactants, plasticizers, printing and dyeing agents, emulsifiers, etc. It has a wide range of uses and its usage is increasing year by year. The market for 1-butene copolymers, especially low-density polyethylene (LLDPE), is promising, which has led to a rapid increase in the demand for 1-butene.

[0003] There are two main traditional 1-butene production routes, one is ethylene dimerization, and the other is mixed C4 separation. In recent years, due to the prominent contradiction between ethylene supply and demand and the high price, the technical route of producing 1-butene by ethylene dimerization faces huge pressure of high production costs and has gradually withdrawn from the market. Mixed C4 mainly contains butadiene, 1-butene, 2-butene, isobutylene, isobutane and n-butane, etc., which are mainly derived from catalytic cracking (FCC), steam cracking to produce ethylene, methanol to olefins (MTO) and other processes. The boiling points of isobutylene and 1-butene in mixed C4 differ by only 0.6℃, and the relative volatility differs by only 0.03. It is difficult to separate the two by general distillation methods. The mixed C4 separation method usually requires the extraction of butadiene or hydrogenation to remove butadiene first, and then the removal of isobutylene by isobutylene etherification, and then the high-purity 1-butene product is obtained after precise separation, and a hydrocarbon mixture rich in 2-butene (mainly 2-butene and n-butane) is obtained at the same time.

[0004] "1-Butene Production Process and Application Overview" reports UOP's MTBE method for producing 1-butene, which first etherifies mixed C4, and then uses a combination of the FLEX process (for adsorption and separation of olefins and alkanes) and the butene isomerization process to produce l-butene. The yield of 1-butene products can reach 90% with this process. However, the technical route is long and the investment is high. Under the current national policy of promoting ethanol gasoline, the living space of MTBE is further squeezed, and there is a possibility that MTBE sales will be difficult and affect the production of 1-butene. For coal-based mixed C4 raw materials with low isobutylene and butadiene content, this route is even less applicable.

[0005] Patent CN112707783A reports a route for producing 1-butene by isomerization. The technology is 1) hydroisomerization, selectively hydrogenating the dienes in the mixed C4 to n-butene and isomerizing 1-butene to 2-butene, and then separating two strands of materials rich in isobutylene and 2-butene respectively through a deisobutylene tower; 2) isomerization, isomerizing 2-butene to 1-butene, and separating two strands of materials rich in 1-butene and 2-butene respectively through a 1-butene concentration tower, wherein the material rich in 2-butene is returned to the inlet of the isomerization reactor, and the material rich in 1-butene goes to the refining unit; and 3) hydrofining to obtain a polymerization-grade 1-butene comonomer. This technical route can be perfectly applied to the production of polymerization-grade 1-butene from coal-based mixed C4 raw materials with low isobutylene and butadiene content. However, the patent does not further process the isobutylene material at the top of the deisobutylene tower. A large amount of 1-butene contained in the material has not been effectively utilized, resulting in great waste. In addition, the production capacity of 1-butene in the patent still needs to be improved. Summary of the invention

[0006] In order to solve one of the above technical problems existing in the prior art, the present invention provides a method for producing 1-butene from a mixed C4 raw material. The method of the present invention comprises sequentially performing hydroisomerization treatment, pretreatment, isomerization treatment and hydrofining treatment on the mixed C4 raw material, and finally obtaining polymerization-grade 1-butene. The method of the present invention returns the 1-butene material separated in the pretreatment process to the hydroisomerization treatment system, which can achieve the purpose of increasing the production of 1-butene by increasing the value of the waste material at the top of the deisobutylene tower in the process, and can also increase the 1-butene production capacity.

[0007] A first aspect of the present invention provides a method for producing 1-butene from a mixed C4 feedstock, comprising the following steps:

[0008] (1) subjecting the mixed C4 raw material to hydroisomerization treatment to obtain a C4 material I rich in 2-butene;

[0009] (2) pretreating the 2-butene-rich C4 material I to obtain an isobutylene-rich material II, a 1-butene-rich material III and a 2-butene-rich C4 material IV, respectively, wherein the 1-butene-rich material III is recycled to step (1) to be mixed with the mixed C4 raw material and subjected to hydroisomerization treatment;

[0010] (3) isomerizing the heavy carbon four material IV rich in 2-butene to obtain a material V containing 1-butene;

[0011] (4) The 1-butene-containing material V is subjected to a hydrorefining treatment to obtain a 1-butene product and a 2-butene-containing material VI.

[0012] According to some embodiments of the present invention, the mixed C4 raw material is a coal-based mixed C4 raw material.

[0013] According to some embodiments of the present invention, the mixed C4 raw material includes 1-butene, 2-butene, 1,3-butadiene, and isobutylene.

[0014] According to some embodiments of the present invention, the mixed C4 raw material includes 1-butene, 2-butene, 1,3-butadiene, isobutylene and aldehyde-ketone oxygen-containing compounds.

[0015] According to some embodiments of the present invention, the mixed C4 raw material includes the following components, in weight percentage: (a) 10% to 35% of 1-butene, (b) 50% to 80% of 2-butene, (c) ≤3% of 1,3-butadiene, (d) 0.5% to 8% of isobutylene, and (e) 300 to 1500 ppm of aldehyde and ketone oxygen-containing compounds.

[0016] In the prior art, the isobutylene material at the top of the deisobutylene tower is generally treated as waste, and a large amount of 1-butene (≥55%) contained in the material is not effectively utilized, resulting in great waste. The present invention collects a portion of the isobutylene material containing a large amount of 1-butene from the top of the deisobutylene tower, and returns it to the hydroisomerization treatment system to mix it with the mixed C4 raw material for hydroisomerization treatment, so that the 1-butene in the isobutylene material can be increased and utilized, which has significant industrial application value.

[0017] According to some embodiments of the present invention, in step (1), the mixed C4 raw material is subjected to a hydroisomerization reaction to selectively hydrogenate 1,3-butadiene to n-butene, and isomerize 1-butene to 2-butene.

[0018] According to some embodiments of the present invention, in step (1), the conditions for hydroisomerization include: the mass space velocity of the fresh material is 1 to 5 h -1 , the liquid phase circulation ratio is 3 to 6, the molar ratio of hydrogen to butadiene is (2 to 5): 1, the temperature is 30 to 100°C, the pressure is 0.1 to 5MPa, and the catalyst is a palladium-based or nickel-based catalyst.

[0019] According to some embodiments of the present invention, in step (1), the amount of 1,3-butadiene remaining after the hydroisomerization treatment is ≤500 ppm, preferably ≤300 ppm.

[0020] According to some embodiments of the present invention, in step (1), the isomerization rate of 1-butene after hydroisomerization treatment is ≥40%, preferably ≥50%.

[0021] According to some embodiments of the present invention, in step (1), the mixed C4 raw material is allowed to enter a hydroisomerization unit, and the mixed C4 raw material undergoes a hydroisomerization reaction, 1,3-butadiene is selectively hydrogenated to n-butene, and 1-butene is isomerized to 2-butene, and a C4 material I rich in 2-butene is obtained at the outlet of the hydroisomerization unit.

[0022] According to some embodiments of the present invention, in step (2), the C4 material I rich in 2-butene enters the deisobutylene tower for pretreatment, and the isobutylene-rich material II is obtained at the top of the tower, the 1-butene-rich material III is obtained from the side of the upper part of the tower, and the heavy C4 material IV rich in 2-butene is obtained in the bottom of the tower.

[0023] According to some embodiments of the present invention, the number of theoretical plates of the deisobutylene tower is 100 to 250, preferably 150 to 250.

[0024] According to some embodiments of the present invention, the uppermost plate of the deisobutylene tower is recorded as the first plate, and the side outlet is located at the 10th to 50th plate of the theoretical plate number of the deisobutylene tower, preferably the 10th to 40th plate.

[0025] According to some embodiments of the present invention, the operating conditions of the pretreatment include: a tower top temperature of 35-80°C, preferably 40-60°C, a tower bottom temperature of 40-100°C, preferably 50-90°C, and a pressure of 0.2-1.0 MPa, preferably 0.3-0.7 MPa.

[0026] According to some embodiments of the present invention, the recovery rate of 2-butene in the deisobutylene tower kettle is ≥75%, preferably ≥90%.

[0027] According to some embodiments of the present invention, in step (2), the content of isobutylene in the heavy C4 stream IV containing 2-butene is ≤0.12 wt % by weight.

[0028] According to some embodiments of the present invention, in step (2), the recovery rate of 1-butene in the 1-butene-rich material III obtained from the upper side of the tower body is ≥65%, preferably ≥80%.

[0029] According to some embodiments of the present invention, in step (3), the C4 material IV rich in 2-butene is isomerized to isomerize 2-butene into 1-butene.

[0030] According to some embodiments of the present invention, in step (3), the C4 material IV rich in 2-butene is fed into an isomerization unit to isomerize 2-butene into 1-butene, and a material V containing 1-butene is obtained at the outlet of the isomerization unit.

[0031] According to some embodiments of the present invention, the isomerization treatment conditions include: the material mass space velocity is 2 to 20 h -1 , pressure is 0.1-1.5MPa, temperature is 250-400°C, selectivity of 2-butene to 1-butene is ≥14%, selectivity of isobutylene is ≤0.1%.

[0032] According to some embodiments of the present invention, the hydrotreating in step (4) includes hydrotreating, purification and separation.

[0033] In some embodiments, the conditions for the hydroprocessing include: the material mass space velocity is 1.5 to 15 h -1 , pressure is 0.6-3.0 MPa, temperature is 30-60°C, and the molar ratio of hydrogen to 1,3-butadiene is 1-50.

[0034] In some embodiments, the loss of 1-butene during the hydroprocessing is ≤5%, preferably ≤3%.

[0035] In some embodiments, the purification process includes removing light components having a boiling point lower than 1-butene in the hydroprocessed product.

[0036] In some embodiments, the separation process is carried out in a 1-butene product tower, and a 1-butene product is obtained at the top of the tower, and a material VI containing 2-butene is obtained at the bottom of the tower. In some embodiments, the 1-butene product tower has 100 to 200 theoretical plates. In some embodiments, the tower pressure of the 1-butene product tower is 0.3 MPa to 0.5 MPa. In some embodiments, the 1-butene purity at the top of the 1-butene product tower is ≥99.0wt%, and the butadiene content is ≤200ppm, preferably ≤120ppm.

[0037] According to some embodiments of the present invention, in step (4), the material V containing 1-butene is introduced into a hydrotreating unit for hydrogenation treatment, purification treatment and separation treatment to obtain a 1-butene product and a material VI containing 2-butene, respectively.

[0038] According to some embodiments of the present invention, the method further comprises: returning the 2-butene-containing material VI obtained in step (4) to step (3) for isomerization treatment.

[0039] A second aspect of the present invention provides a device for producing 1-butene from a mixed C4 feedstock, comprising:

[0040] A hydroisomerization unit, which is used to perform hydroisomerization treatment on the mixed C4 raw material to obtain a C4 material I rich in 2-butene;

[0041] A deisobutylene tower, wherein a side outlet is provided on the upper part of the tower body, wherein the side outlet is connected to the mixed C4 raw material inlet of the hydroisomerization unit, and the deisobutylene tower is used to pretreat the C4 material I rich in 2-butene to obtain a material II rich in isobutylene, a material III rich in 1-butene and a heavy C4 material IV rich in 2-butene;

[0042] an isomerization unit, which is used to isomerize the heavy carbon four material IV rich in 2-butene to obtain a material V containing 1-butene; and

[0043] The hydrofining unit is used to perform hydrofining treatment on the material V containing 1-butene to obtain a 1-butene product and a material VI containing 2-butene.

[0044] In the device of the present application, by connecting the side sampling outlet of the deisobutylene tower with the mixed C4 raw material inlet of the hydroisomerization unit, the 1-butene-rich material III obtained by the side sampling can be recycled back to the hydroisomerization unit to be mixed with the mixed C4 raw material and subjected to hydroisomerization treatment, thereby realizing the recycling of the 1-butene-containing material III, improving the single-pass isomerization rate of 1-butene, and increasing the yield of 1-butene, which has greater competitiveness especially at the end of the isomerization reaction.

[0045] According to some embodiments of the present invention, the hydrorefining unit includes a hydrogenation unit, a purification unit and a separation unit connected in sequence, the hydrogenation unit is used to hydrogenate the material V containing 1-butene to obtain a hydrogenated product, the purification unit is used to remove light components with a boiling point lower than 1-butene in the hydrogenated product, and the separation unit is used to separate 1-butene from the purified material to obtain a 1-butene product and a material VI containing 2-butene, respectively.

[0046] According to some embodiments of the present invention, the theoretical number of plates of the deisobutylene tower is 100 to 250, preferably 150 to 250. In some embodiments, the uppermost plate of the deisobutylene tower is recorded as the first layer, and the side outlet is located at the 10th to 50th layer of the deisobutylene tower, preferably the 10th to 40th layer; the top of the deisobutylene tower obtains material II rich in isobutylene, the side outlet obtains material III rich in 1-butene, and the bottom of the tower obtains heavy carbon four material IV rich in 2-butene.

[0047] According to some embodiments of the present invention, the outlet of the hydrotreating unit is also connected to the inlet of the isomerization unit, so that the 2-butene-containing material VI flowing out of the hydrotreating unit is returned to the isomerization unit.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] (1) The method and system of the present invention can improve the isomerization efficiency in the hydroisomerization process, obtain a higher 1-butene conversion rate and a higher 2-butene selectivity, and can prevent the formation of over-hydrogenation product butane to the greatest extent.

[0050] (2) The method and system of the present invention can simultaneously achieve the removal of isobutylene and the recovery and reuse of 1-butene materials produced during the hydroisomerization process.

[0051] (3) The method and system of the present invention have a short process flow and low investment. They are highly competitive during the life cycle of the catalyst, especially at the end of the catalyst life when the isomerization rate is low. They can increase the 1-butene production capacity by 10 to 30%, and have high industrial application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 The figure is a flow chart of the 1-butene production process in the prior art.

[0053] Figure 2 This is a process flow chart for producing 1-butene in Example 1 of the present invention.

[0054] Explanation of the reference numerals: A: hydroisomerization unit, B: deisobutylene tower, C: isomerization unit, D: hydrotreating unit, 1: mixed C4 raw material, 2: C4 material I, 3: heavy C4 material IV rich in 2-butene, 4: material III rich in 1-butene, 5: material II rich in isobutylene, 6: material V containing 1-butene, 7: 1-butene product VII, 8: material VI containing 2-butene. DETAILED DESCRIPTION

[0055] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments and drawings. The specific embodiments described herein are only used to explain the present invention and are not intended to constitute any limitation to the present invention.

[0056] The endpoints and any values ​​of the scope disclosed in the present invention are not limited to the precise scope or value, and these scopes or values ​​should be understood to include values ​​close to these scopes or values. For numerical ranges, the endpoint values ​​of each scope, the endpoint values ​​of each scope and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in this article. Hereinafter, in principle, each technical solution can be combined with each other to obtain a new technical solution, which should also be regarded as specifically disclosed in this article.

[0057] The raw materials used in the examples and comparative examples, unless otherwise specified, are disclosed in the prior art, for example, they can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0058] Example 1

[0059] use Figure 2 In the process flow shown, logistics 1 is a mixed C4 raw material, and its composition in weight percentage is:

[0060] 27% 1-butene; 61% 2-butene; 1.5% 1,3-butadiene; 4.5% isobutylene, 1000ppm aldehydes and ketones oxygenated compounds; the rest is butane components, and its flow rate is 1000kg / h.

[0061] The stream 1 is sent to the hydroisomerization unit to obtain a stream 2, which has the composition of 11% 1-butene; 77.5% 2-butene; 100 ppm 1,3-butadiene; 4.5% isobutylene; and the remainder is butane components.

[0062] Logistics 2 is sent to a deisobutylene tower. The theoretical number of trays in the pretreatment tower is 200. Logistics 5 is taken out at the top of the tower with a flow rate of 63 kg / h. Material 4 is side-taken at the 10th theoretical tray with a flow rate of 200 kg, wherein the isobutylene content is 19% and the 1-butene content is 60.5%. Material 4 is mixed with logistics 1 and recycled to the hydroisomerization unit. Logistics 3 rich in 2-butene is obtained in the bottom of the tower with a flow rate of 937 kg / h, wherein the isobutylene flow rate is 0.001 kg / h and the 2-butene content is 871 kg / h.

[0063] Stream 3 is sent to the isomerization unit at 310°C, pressure 0.45 MPaG, and space velocity 5 h -1 When the above steps are repeated, logistics 6 is obtained, wherein the 1-butene content of logistics 6 is 15.5 wt%, the isobutylene content is 0.02 wt%, and the butadiene content is 0.01 wt%.

[0064] Logistics 6 enters the hydrotreating unit to obtain 1-butene product logistics 7 and circulating logistics 8, wherein the flow rate of logistics 7 is 340 kg / h, the 1-butene content is 99.3%, the isobutylene content is 0.15%, and the butadiene content is 0.012 wt%; the flow rate of circulating logistics 8 is 1100 kg / h.

[0065] Comparative Example 1

[0066] use Figure 1 In the process shown, logistics 1 is a mixed C4 raw material, and its composition by weight percentage is: 27% 1-butene; 61% 2-butene; 1.5% 1,3-butadiene; 4.5% isobutylene, 1000ppm aldehyde and ketone oxygen-containing compounds; the rest is butane components, and its flow rate is 1000kg / h.

[0067] The stream 1 is sent to the hydroisomerization unit to obtain a stream 2, which has the composition of 13% 1-butene, 75.5% 2-butene, 150 ppm 1,3-butadiene, 4.5% isobutylene, and the remainder is butane components.

[0068] Logistics 2 is sent to the deisobutylene tower. The theoretical number of trays of the pretreatment tower is 200. Logistics 5 is extracted at the top of the tower with a flow rate of 220 kg / h. Logistics 3 rich in 2-butene is obtained at the bottom of the tower with a flow rate of 780 kg / h, of which the isobutylene flow rate is 0.001 kg / h and the 2-butene content is 725 kg / h.

[0069] Stream 3 is sent to the isomerization unit at 310°C, pressure 0.45 MPaG, and space velocity 5 h -1 When the above steps are repeated, logistics 6 is obtained, wherein the 1-butene content of logistics 6 is 15.5 wt%, the isobutylene content is 0.02 wt%, and the butadiene content is 0.01 wt%.

[0070] Logistics 6 enters the hydrotreating unit to obtain 1-butene product logistics 7 and circulating logistics 8, wherein the flow rate of logistics 7 is 283 kg / h, the 1-butene content is 99.3%, the isobutylene content is 0.15%, and the butadiene content is 0.012 wt%; the flow rate of circulating logistics 8 is 930 kg / h.

[0071] Compared with Comparative Example 1, Example 1 of the present invention not only improves the single-pass conversion rate of 1,3-butadiene and 1-butene in the raw material, but also ultimately increases the 1-butene production capacity by about 20% by recycling the side-produced material 4 from the top of the deisobutylene tower to the hydroisomerization unit.

[0072] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. All technical variations made according to the technical solution of the present invention fall within the protection scope of the present invention.

Claims

1. A method for producing 1-butene from a mixed C4 raw material, comprising the following steps: (1) subjecting the mixed C4 raw material to hydroisomerization treatment to obtain a C4 material I rich in 2-butene; (2) pretreating the 2-butene-rich C4 material I to obtain an isobutylene-rich material II, a 1-butene-rich material III and a 2-butene-rich C4 material IV, respectively, wherein the 1-butene-rich material III is recycled to step (1) to be mixed with the mixed C4 raw material and subjected to hydroisomerization treatment; (3) isomerizing the heavy carbon four material IV rich in 2-butene to obtain a material V containing 1-butene; (4) The 1-butene-containing material V is subjected to a hydrorefining treatment to obtain a 1-butene product and a 2-butene-containing material VI.

2. The method according to claim 1, characterized in that: The mixed C4 raw material is a coal-based mixed C4 raw material; Preferably, the mixed C4 raw material includes 1-butene, 2-butene, 1,3-butadiene, isobutylene and optional aldehyde and ketone oxygen-containing compounds; Preferably, the mixed C4 raw material comprises the following components, measured in weight percentage: (a) 10% to 35% of 1-butene, (b) 50% to 80% of 2-butene, (c) ≤3% of 1,3-butadiene, (d) 0.5% to 8% of isobutylene, and (e) 300 to 1500 ppm of aldehyde and ketone oxygen-containing compounds.

3. The method according to claim 1 or 2, characterized in that: In step (1), the mixed C4 raw material is subjected to a hydroisomerization reaction to selectively hydrogenate 1,3-butadiene to n-butene, and isomerize 1-butene to 2-butene; Preferably, the conditions for the hydroisomerization in step (1) include: the mass space velocity of the fresh material is 1 to 5 h -1 , a liquid phase circulation ratio of 3 to 6, a hydrogen to butadiene molar ratio of (2 to 5): 1, a temperature of 30 to 100° C., a pressure of 0.1 to 5 MPa, and a catalyst of palladium or nickel; and / or, after hydroisomerization treatment, the amount of 1,3-butadiene remaining is ≤500 ppm, preferably ≤300 ppm, and / or, a 1-butene isomerization rate is ≥40%, preferably ≥50%.

4. The method according to any one of claims 1 to 3, characterized in that In step (2), the C4 material I rich in 2-butene is introduced into a deisobutylene tower for pretreatment, and the isobutylene-rich material II is obtained at the top of the tower, the 1-butene-rich material III is obtained from the side of the upper part of the tower, and the heavy C4 material IV rich in 2-butene is obtained at the bottom of the tower.

5. The method according to claim 4, characterized in that The number of theoretical plates of the deisobutylene tower is 100 to 250; the uppermost plate of the deisobutylene tower is marked as the first layer, and the side outlet is located at the 10th to 50th layers of the deisobutylene tower; Preferably, the operating conditions of the pretreatment include: a tower top temperature of 35 to 80°C, preferably 40 to 60°C, a tower bottom temperature of 40 to 100°C, preferably 50 to 90°C, and a pressure of 0.2 to 1.0 MPa, preferably 0.3 to 0.7 MPa; and / or, The recovery rate of 2-butene in the deisobutylene tower kettle is ≥75%, preferably ≥90%; and / or, in terms of weight percentage, the content of isobutylene in the heavy carbon four stream IV containing 2-butene is preferably ≤0.12wt%; and / or, The recovery rate of 1-butene in the 1-butene-rich material III obtained from the upper side of the tower body is ≥65%, preferably ≥80%.

6. The method according to any one of claims 1 to 5, characterized in that: In step (3), the C4 material IV rich in 2-butene is isomerized to isomerize 2-butene into 1-butene; Preferably, the isomerization treatment conditions include: the material mass space velocity is 2 to 20 h -1 , pressure is 0.1-1.5MPa, temperature is 250-400°C, selectivity of 2-butene to 1-butene is ≥14%, selectivity of isobutylene is ≤0.1%.

7. The method according to any one of claims 1 to 6, characterized in that: The hydrofining in step (4) includes hydrotreating, purification and separation; wherein the conditions of the hydrotreating include: the mass space velocity of the material is 1.5 to 15 h -1 , the pressure is 0.6-3.0 MPa, the temperature is 30-60°C, the molar ratio of hydrogen to 1,3-butadiene is 1-50; and / or, the loss of 1-butene in the hydrogenation treatment is ≤5%, preferably ≤3%; The purification treatment includes removing light components with a boiling point lower than 1-butene in the hydroprocessing product; The separation treatment is carried out in a 1-butene product tower, and a 1-butene product is obtained at the top of the tower, and a material VI containing 2-butene is obtained at the bottom of the tower; preferably, the 1-butene product tower has 100 to 200 theoretical plates; and / or the tower pressure of the 1-butene product tower is 0.3 MPa to 0.5 MPa; and / or the 1-butene purity at the top of the 1-butene product tower is ≥99.0wt%, and the butadiene content is ≤200ppm, preferably ≤120ppm.

8. The method according to any one of claims 1 to 7, characterized in that: The method further comprises: returning the 2-butene-containing material VI obtained in step (4) to step (3) for isomerization treatment.

9. A device for producing 1-butene from a mixed C4 feedstock, comprising: A hydroisomerization unit, which is used to perform hydroisomerization treatment on the mixed C4 raw material to obtain a C4 material I rich in 2-butene; A deisobutylene tower, wherein a side outlet is provided on the upper part of the tower body, wherein the side outlet is connected to the mixed C4 raw material inlet of the hydroisomerization unit, and the deisobutylene tower is used to pretreat the C4 material I rich in 2-butene to obtain a material II rich in isobutylene, a material III rich in 1-butene and a heavy C4 material IV rich in 2-butene; An isomerization unit, which is used to isomerize the heavy carbon four material IV rich in 2-butene to obtain a material V containing 1-butene; as well as The hydrofining unit is used to perform hydrofining treatment on the material V containing 1-butene to obtain a 1-butene product and a material VI containing 2-butene.

10. The device according to claim 9, characterized in that The theoretical number of plates of the deisobutylene tower is 100 to 250; preferably, the uppermost plate of the deisobutylene tower is designated as the first plate, and the side outlet is located at the 10th to 50th plates of the deisobutylene tower; and / or, The outlet of the hydrofining unit is also connected to the inlet of the isomerization unit, so that the 2-butene-containing material VI flowing out of the hydrofining unit is returned to the isomerization unit.

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