Ethylene oligomerization production process

Abstract

The invention relates to the technical field of ethylene polymerization, in particular to an ethylene oligomerization production process which comprises a main reactor and a heat exchanger communicated with the main reactor, and a first circulating pump is mounted between the main reactor and the heat exchanger; the plug flow reactor tube stack is communicated with the main reactor, and a second circulating pump is arranged between the main reactor and the plug flow reactor tube stack; ethylene and a catalyst are injected into the main reactor to react to form reaction liquid; part of the reaction liquid enters the heat exchanger for heat exchange through the first circulating pump, and the reaction liquid after heat exchange is sprayed back into the main reactor from the sprayer; and part of the reaction liquid flows through the plug flow reactor pipe group through the second circulating pump and is discharged after the reaction is finished. The sectional plug flow reactor is added, so that the conversion per pass of the reaction is improved to 92%, the use efficiency of the catalyst is improved, the reaction conversion rate is improved, the dosage of the catalyst is reduced, and the energy consumption of a subsequent purification section is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of ethylene polymerization, and specifically to an ethylene oligomerization production process. Background Art

[0002] In ethylene oligomerization reactions, stirred tank reactors, bubble point reactors, or loop reactors are often used for the reaction. After homogeneous catalytic reaction, the catalyst and the product flow out of the reactor simultaneously, as Figure 1 shown. In this process, the catalyst still has relatively high activity, so the catalyst is not fully utilized, resulting in catalyst loss; at the same time, unreacted ethylene also flows out with the material, resulting in a reduction in the single-pass conversion rate of the reactor and increasing the energy consumption of the subsequent purification section.

[0003] Based on this, an ethylene oligomerization production process is proposed. Summary of the Invention

[0004] To overcome the deficiencies of the prior art, the present invention provides an ethylene oligomerization production process. The added segmented plug flow reactor improves the conversion rate, helps reduce the amount of catalyst used, reduces the energy consumption of the subsequent purification section, and lowers the production cost.

[0005] To achieve the above object, the present invention provides the following technical solution: an ethylene oligomerization production process, including (1) a main reactor, (2) a heat exchanger connected to the main reactor through a circulation pump P1; (3) a plug flow reactor connected to the main reactor through a circulation pump P2;

[0006] Ethylene, 1-butene, a catalyst, and a cocatalyst are injected into the main reactor for reaction to form a reaction solution; part of the reaction solution enters the heat exchanger through the circulation pump P1 for heat exchange, and the heat-exchanged reaction solution flows back into the main reactor; part of the reaction solution flows into the plug flow reactor tube bundle through the circulation pump P2 and is discharged after at least 10% of the ethylene is consumed.

[0007] The main reactor can be a stirred tank reactor, a loop reactor, or a bubble reactor. The plug flow reactor can be a loop-type or non-loop-type pipeline, or a stirred or non-stirred tank body with or without an external or internal cooling circuit.

[0008] A distributor N2 for dispersing ethylene into bubbles is installed in the main reactor, and a sprayer N1 is installed at the top of the reactor R0;

[0009] The main reactor is provided with an ethylene feed port, a 1-butene feed port, a catalyst feed port, and a cocatalyst feed port;

[0010] A heat exchanger E1 connected to the main reactor, and a first circulation pump P1 is installed between the main reactor and the heat exchanger;

[0011] A plug flow reactor tube group connected to the main reactor, and a second circulation pump P2 is installed between the main reactor and the plug flow reactor tube group.

[0012] Preferably, the segmented loop tube is composed of 1-10 groups of plug flow reactors connected in series.

[0013] Preferably, in step (3), the residence time of the reaction liquid in the plug flow reactor tube group is 0.1-10 h. Preferably 0.1-2 h;

[0014] Preferably, in the plug flow reactor tube group, the residence time of the reaction liquid in the first-stage plug flow reactor is 0.1-1 h; the residence time in the second-stage plug flow reactor is 0.1-1 h; the residence time in the third-stage plug flow reactor is 0.1-1 h; the residence time in the fourth-stage plug flow reactor is 0.1-1 h; the residence time in the fifth-stage plug flow reactor is 0.1-1 h.

[0015] Preferably, in step (3), the temperature of the plug flow reactor is 30-130 °C. Preferably 40-70 °C.

[0016] The present invention provides an ethylene oligomerization production process, which has the following beneficial effects compared with the prior art:

[0017] Compared with the traditional reaction kettle, the present invention, in cooperation with the added plug flow reactor, increases the single-pass conversion rate of the reaction to 92%, improves the use efficiency of the catalyst, increases the reaction conversion rate, helps to reduce the dosage of the catalyst, reduces the energy consumption in the subsequent purification section. Most importantly, this device will reduce the amount of ethylene that needs to be recovered and recycled downstream, reducing the production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation to the present application. In the drawings:

[0019] Figure 1 It is the ethylene oligomerization production reactor and reaction flow chart in the prior art;

[0020] Figure 2 It is the ethylene oligomerization production reactor and reaction flow chart of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] The following examples are used to illustrate in detail the implementation manners of the present application, so as to fully understand how the present application uses technical means to solve technical problems and achieve the realization process of technical effects and implement accordingly.

[0022] Example 1

[0023] The ethylene oligomerization production reactor includes a high-pressure reactor with a stirring device and 5 sets of plug flow reactors. An ethylene oligomerization production process includes the following steps:

[0024] (1) Inject ethylene, catalyst and 1-butene into the stirred high-pressure reactor for reaction, with a stirring speed of 300 rpm, and control the residence time of the reaction liquid in the reactor to be 2 h to form a reaction liquid;

[0025] (2) Turn off the stirring of the reactor, and part of the reaction liquid enters the heat exchanger through the first circulation pump P1 for heat exchange, and the heat-exchanged reaction liquid at 45 °C is sprayed back into the bubble reactor from the sprayer;

[0026] (3) Part of the reaction liquid flows through the plug flow reactor tube bank through the second circulation pump B, and is discharged after the reaction is completed.

[0027] (4) The residence time in the plug flow reactor is 0.5 h, and about 50% of the residual ethylene is consumed.

[0028] Example 2

[0029] The ethylene oligomerization production reactor includes a high-pressure reactor with a stirring device and 5 sets of plug flow reactors. An ethylene oligomerization production process includes the following steps:

[0030] (1) Inject ethylene, catalyst and 1-butene into the stirred high-pressure reactor for reaction, with a stirring speed of 300 rpm, and control the residence time of the reaction liquid in the reactor to be 2 h to form a reaction liquid;

[0031] (2) Continue to stir at a speed of 300 rpm, and part of the reaction liquid enters the heat exchanger through the first circulation pump P1 for heat exchange, and the heat-exchanged reaction liquid at 45 °C is sprayed back into the bubble reactor from the sprayer;

[0032] (3) Part of the reaction liquid flows through the plug flow reactor tube bank through the second circulation pump P2, and is discharged after the reaction is completed.

[0033] (4) The residence time in the plug flow reactor is 1 h, and about 70% of the residual ethylene is consumed. The above ethylene oligomerization production process is as follows:

[0034]

[0035]

[0036] Comparative Example 1

[0037] An ethylene polymerization production process uses a continuous stirred tank reactor to carry out the reaction alone, that is, ethylene, catalyst and 1-butene are injected into the continuous stirred tank reactor for reaction, and are discharged after the reaction is completed. Specifically as follows:

[0038]

[0039]

[0040] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An ethylene polymerization production reactor, characterized in that: It comprises a main reactor, and an ethylene feed inlet and a catalyst feed inlet are arranged at the bottom of the main reactor; a heat exchanger connected to the main reactor, and a first circulation pump installed between the main reactor and the heat exchanger; A plug flow reactor pipe group is connected to the main reactor, and a second circulation pump is installed between the main reactor and the plug flow reactor pipe group.

2. The ethylene polymerization production reactor according to claim 1, characterized in that: A distributor for dispersing ethylene into bubbles is installed at the bottom of the main reactor, and a sprayer is installed at the top of the main reactor.

3. The ethylene polymerization production reactor according to claim 2, characterized in that: The plug flow reactor tube group is composed of 5 groups of plug flow reactors connected in series.

4. An ethylene polymerization production process, using the production reactor described in claim 3, characterized in that: The following steps are involved: (1) injecting ethylene, 1-butene, a catalyst and a co-catalyst into a main reactor for reaction to form a reaction liquid; (2) Part of the reaction liquid enters the heat exchanger through the first circulation pump for heat exchange, and the reaction liquid after heat exchange is sprayed back into the main reactor from the sprayer; (3) Part of the reaction liquid flows through the plug flow reactor tube group through the second circulation pump and is discharged after the reaction is completed.

5. The ethylene oligomerization production process according to claim 4, characterized in that: In step (1), the catalyst is tetrabutyl titanate and the co-catalyst is triethylaluminum.

6. The ethylene oligomerization production process according to claim 4, characterized in that: In step (1), the residence time of the reaction solution in the main reactor is 2 hours.

7. The ethylene oligomerization production process according to claim 4, characterized in that: In step (2), the temperature of the reaction liquid after heat exchange is 45-60°C.

8. The ethylene oligomerization production process according to claim 4, characterized in that: In step (3), the residence time of the reaction liquid in the plug flow reactor tube group is 0.5-1h.

9. The ethylene oligomerization production process according to claim 8, characterized in that: In step (3), the temperature inside the plug flow reactor tube group is 50-70°C.

10. The ethylene oligomerization production process according to claim 9, characterized in that: In the plug flow reactor tube group, the residence time of the reaction liquid in the first plug flow reactor is 0.1-0.2h, and the reaction temperature is 53-55°C; the residence time in the second plug flow reactor is 0.1-0.2h, and the reaction temperature is 55-60°C; the residence time in the third plug flow reactor is 0.1-0.2h, and the reaction temperature is 60-65°C; the residence time in the fourth plug flow reactor is 0.1-0.2h, and the reaction temperature is 65-70°C; the residence time in the fifth plug flow reactor is 0.1-0.2h, and the reaction temperature is 55-60°C.

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