Isomerization system and process for 1-butene in etherified C4

Abstract

The invention relates to the technical field of chemical separation, and discloses an isomerization system and process for 1-butene in etherified C4. Comprising an isomerization reactor, a coalescer, a heat exchanger, a static mixer and a filter, an inlet of the coalescer is connected with an etherified C4 pipeline, an outlet pipeline of the coalescer penetrates through the heat exchanger to be connected with an inlet of the static mixer, the inlet of the static mixer is further connected with a hydrogen pipeline, and an outlet of the static mixer is connected with an inlet of the isomerization reactor. An isomerization reactor outlet is connected with a filter inlet, and a filter outlet pipeline enters the isobutane separation tower. According to the method, 1-butene in etherified C4 is isomerized, and after 1-butene is isomerized into 2-butene by utilizing the relatively small relative volatility of 1-butene and iso-butane and the relatively large relative volatility of 2-butene and iso-butane, the content of 1-butene in the raw material is reduced, the separation difficulty of iso-butane is reduced, and iso-butane with the same purity is obtained; the reflux ratio of the isobutane separation tower can be reduced, and the purpose of saving energy is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of chemical separation, and in particular to a system and process for isomerizing 1-butene in post-ether C4. Background Art

[0002] The pre-ether C4 is reacted with isobutylene and methanol in the methyl tert-butyl ether (MTBE) unit to generate MTBE and post-ether C4, which is used as the raw material for isobutane dehydrogenation and n-butene isomerization in the C4 deep processing project. The composition of the post-ether C4 fraction is shown in Table 1.

[0003] Table 1 Composition of C4 fraction after etherification

[0004] Serial number Components Mass fraction wt% 1 PROPA-01(Propane) 0.00％ 2 ISOBU-01(isobutane) 44.39％ 3 N-BUT-01(n-butane) 16.00％ 4 TRANS-01(trans-2-butene) 15.50％ 5 1-BUT-01(1-Butene) 13.30％ 6 CIS-2-01(cis-2-butene) 10.50％ 7 ISOBU-02(isobutylene) 0.11％ 8 1:3-B-01(1,3-butadiene) 0.12％ 9 N-PEN-01(C5) 0.02％ 10 DIMET-01 (dimethyl ether) 0.06％ total 100％

[0005] Isobutane is separated from the post-etherification C4 as a raw material for isobutane dehydrogenation, while reducing the processing load of the n-butene isomerization raw material. Since the relative volatility of each component is small when isobutane is separated from the post-etherification C4 (the boiling points of the main components are from low to high: isobutane < 1-butene < n-butane < trans-2-butene < cis-2-butene), 1-butene is easily distilled from the top of the tower, and a large reflux ratio is required to obtain high-purity isobutane, resulting in high energy consumption of the isobutane separation tower. Summary of the invention

[0006] The purpose of the present invention is to overcome the disadvantage of high energy consumption in separating isobutane from C4 after etherification, and to provide a system and process for isomerizing 1-butene in C4 after etherification.

[0007] In order to achieve the above-mentioned purpose, the technical scheme of the present invention is: a 1-butene isomerization system in post-ether carbon four, comprising an isomerization reactor, a coalescer, a heat exchanger, a static mixer and a filter, the coalescer inlet is connected to the post-ether carbon four pipeline, the coalescer outlet pipeline passes through the heat exchanger and is connected to the static mixer inlet, the static mixer inlet is also connected to a hydrogen pipeline, the static mixer outlet is connected to the isomerization reactor inlet, the isomerization reactor outlet is connected to the filter inlet, the filter outlet pipeline enters the isobutane separation tower, and the isomerization reactor is provided with upper and lower catalyst layers.

[0008] Furthermore, the catalyst layer is an olefin double bond isomerization catalyst.

[0009] Furthermore, the isomerization reactor is provided with a hydrogen replenishment port between the upper and lower catalyst layers, which is used as a standby when the amount of hydrogen added at the inlet of the isomerization reactor is insufficient.

[0010] Furthermore, the static mixer inlet pipeline is provided with a check valve, and the hydrogen pipeline is connected to the check valve.

[0011] Another technical scheme of the present invention is: a production process for isomerization of 1-butene in post-etherified C4, using the 1-butene in post-etherified C4 isomerization system, the post-etherified C4 produced as a by-product of the MTBE device is subjected to a coalescer to remove free water, then heated to 40-60° C. by a heat exchanger, mixed with hydrogen by a static mixer and entering an isomerization reactor, in the isomerization reactor, 1-butene is isomerized to 2-butene under the action of an olefin double bond isomerization catalyst under a hydrogen environment, and the reaction product is filtered to remove solid particles and then enters an isobutane separation tower for isobutane separation.

[0012] Further, the mass ratio of hydrogen to carbon four after ether is 2 to 4:10000

[0013] Furthermore, the isomerization reactor pressure is 1.5 MPa.

[0014] The beneficial effects of the present invention are as follows: the present invention isomerizes 1-butene in post-ether carbon four, utilizes the smaller relative volatility of 1-butene and isobutane and the larger relative volatility of 2-butene and isobutane, and after 1-butene is isomerized to 2-butene, the 1-butene content in the raw material is reduced, the difficulty of separating isobutane is reduced, and isobutane of the same purity is obtained, and the reflux ratio of the isobutane separation tower can be reduced, thereby achieving the purpose of energy saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a schematic diagram of the isomerization system of the present invention.

[0016] In the figure: 1. Isomerization reactor; 2. Coalescer; 3. Heat exchanger; 4. Filter; 5. Static mixer; 6. Check valve; 7. Hydrogen replenishment port. DETAILED DESCRIPTION

[0017] The olefin double bond isomerization catalyst used in the present invention is purchased from the olefin double bond isomerization catalyst SQ403 produced by Dongying Keerte New Materials Co., Ltd.

[0018] Example:

[0019] like Figure 1As shown, a 1-butene isomerization system in post-ether C4 includes an isomerization reactor 1, a coalescer 2, a heat exchanger 3, a static mixer 5 and a filter 4, the inlet of the coalescer 2 is connected to the post-ether C4 pipeline, the outlet pipeline of the coalescer 3 passes through the heat exchanger 3 and is connected to the inlet of the static mixer 5, a check valve 6 is provided on the inlet pipeline of the static mixer 5, the static mixer 5 is connected to the hydrogen pipeline through the check valve 6, the outlet of the static mixer 5 is connected to the inlet of the isomerization reactor 1, the outlet of the isomerization reactor 1 is connected to the inlet of the filter 4, the outlet pipeline of the filter 4 enters the isobutane separation tower, and the isomerization reactor 1 is provided with upper and lower catalyst layers, and the catalyst layers are olefin double bond isomerization catalysts. The isomerization reactor 1 is provided with a hydrogen replenishment port 7 between the upper and lower catalyst layers.

[0020] A production process for isomerization of 1-butene in post-ether C4, wherein the post-ether C4 produced by the MTBE device is subjected to a coalescer 2 to remove free water, then heated to 50°C by a heat exchanger 3, mixed with hydrogen by a static mixer 5 and enters an isomerization reactor 1, wherein the mass ratio of hydrogen to post-ether C4 is 4:10000, and the pressure of the isomerization reactor 1 is 1.5 MPa. In the isomerization reactor 1, 1-butene is isomerized to 2-butene under the action of an olefin double bond isomerization catalyst under a hydrogen environment, and the reaction product is subjected to a filter 4 to remove solid particles and then enters an isobutane separation tower for isobutane separation. After the post-ether C4 passes through the isomerization reactor 1, the changes in the post-ether C4 fraction are shown in Table 2.

[0021] Table 2 Comparison of C4 composition after ether before and after isomerization

[0022]

[0023] Comparison between the etherified C4 after isomerization in the isomerization reactor and the etherified C4 before isomerization entering the isobutane separation tower to separate isobutane:

[0024] Ether post-C4 processing capacity: 41310Kg / h;

[0025] The product indicators of the top and bottom of the C4-isobutane separation tower before and after isomerization are the same.

[0026] 1) The isobutane content at the top of the tower is ≮95 mol%;

[0027] 2) The olefin content at the bottom of the tower is ≮65 mol%.

[0028] The heat load and steam consumption of the bottom reboiler of the isobutane separation tower before and after isomerization are shown in Table 3.

[0029] Table 3 Comparison of heat load and steam consumption of the bottom reboiler of the isobutane separation tower before and after isomerization

[0030] Before heterogeneity After heterogeneity Heat load MKcal / h 16.03 10.13 Steam volume t / h 32 20.26

[0031] As shown in Table 3, 1-butene isomerizes to ether and then C4 into the isobutane separation tower to separate isobutane, which can reduce the energy consumption of the isobutane separation tower and achieve the purpose of energy saving.

[0032] The above-described embodiments are only preferred solutions of the present invention and are not intended to limit the present invention in any form. Other variations and modifications are possible without exceeding the technical solutions described in the claims.

[0033] In the description of the present invention, it is necessary to understand that the terms indicating orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

Claims

1. A system for isomerizing 1-butene in post-ether C4, characterized in that: The invention comprises an isomerization reactor, a coalescer, a heat exchanger, a static mixer and a filter. The inlet of the coalescer is connected to a post-ether C4 pipeline. The outlet pipeline of the coalescer passes through the heat exchanger and is connected to the inlet of the static mixer. The inlet of the static mixer is also connected to a hydrogen pipeline. The outlet of the static mixer is connected to the inlet of the isomerization reactor. The outlet of the isomerization reactor is connected to the inlet of the filter. The outlet pipeline of the filter enters an isobutane separation tower. The isomerization reactor is provided with two upper and lower catalyst layers.

2. The 1-butene isomerization system in post-ether C4 according to claim 1, characterized in that: The catalyst layer is an olefin double bond isomerization catalyst.

3. The 1-butene isomerization system in post-ether C4 according to claim 1, characterized in that: The isomerization reactor is provided with a hydrogen replenishing port between the upper and lower catalyst layers.

4. The 1-butene isomerization system in post-ether C4 according to claim 1, characterized in that: The static mixer inlet pipeline is provided with a check valve, and the hydrogen pipeline is connected to the check valve.

5. A process for isomerization production of 1-butene in post-etherification C4, characterized in that: By using the isomerization system for 1-butene in post-ether C4 as described in any one of claims 1 to 4, the post-ether C4 produced as a by-product of the MTBE device is subjected to a coalescer to remove free water, then heated to 40-60° C. by a heat exchanger, mixed with hydrogen by a static mixer and fed into an isomerization reactor, 1-butene is isomerized into 2-butene under the action of an olefin double bond isomerization catalyst in the isomerization reactor under a hydrogen environment, and the reaction product is filtered to remove solid particles and then fed into an isobutane separation tower for isobutane separation.

6. The isomerization production process of 1-butene in post-ether C4 according to claim 5, characterized in that: The mass ratio of the hydrogen to the etherified C4 is 2-4:10000.

7. The isomerization production process of 1-butene in post-ether C4 according to claim 5, characterized in that: The isomerization reactor pressure is 1.5 MPa.

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