Reactor for directly preparing 6-aminocapronitrile from cyclohexanone oxime

Abstract

A reactor for directly preparing aminocapronitrile from cyclohexanone oxime comprises a reaction tower, a feeding port is formed in the top of the reaction tower, a discharging port is formed in the bottom of the reaction tower, a supporting plate is arranged in the reaction tower, and an inner cavity of the reaction tower is divided into a heat exchange reaction cavity and a common reaction cavity by the supporting plate. The heat exchange reaction cavity is positioned above the common reaction cavity and is communicated with the common reaction cavity, a heat exchange reaction device is arranged in the heat exchange reaction cavity, and a fixed bed reactor is arranged in the common reaction cavity; according to the utility model, the Beckmann rearrangement reaction and the ammonification reaction are integrated in one reactor, so that not only is the process flow simplified, but also the target product yield of 6-amino-capronitrile is remarkably improved, and the economical efficiency and feasibility of the production process are greatly enhanced.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical production, in particular to a reactor for directly preparing 6-aminocapronitrile from cyclohexanone oxime. Background Art

[0002] The preparation of hexamethylenediamine mainly includes the butadiene method, adipic acid method, acrylonitrile method, and cyclohexanone oxime or caprolactam method according to different raw materials. Among them, the direct cyanidation method of butadiene has potential safety hazards due to the use of highly toxic hydrogen cyanide; the acrylonitrile method is difficult to industrialize due to high energy consumption and the strong toxicity and corrosiveness of acrylonitrile itself; the adipic acid method has difficulties in product separation, low conversion rate and selectivity due to complex process and many side reactions.

[0003] In contrast, the cyclohexanone oxime or caprolactam method is more superior due to its simple process flow, few by-products and easy subsequent separation. Especially when using cyclohexanone oxime as the raw material, 6-aminocapronitrile is first generated through Beckmann rearrangement reaction and ammoniation reaction, and then hexamethylenediamine is generated through hydrogenation reaction. With the growth of caprolactam production capacity and the decline of raw material prices, the economy of this method has become increasingly prominent. However, in the existing technology, the Beckmann rearrangement reaction and ammoniation reaction usually need to be carried out in two independent reactors, which increases the equipment cost and affects the product yield. Summary of the Utility Model

[0004] In view of the above problems, the technical problem to be solved by the utility model is to provide a reactor for directly preparing 6-aminocapronitrile from cyclohexanone oxime. This device integrates the Beckmann rearrangement reaction and ammoniation reaction in one reactor. This design not only simplifies the process flow but also significantly improves the yield of the target product 6-aminocapronitrile, thus greatly enhancing the economy and feasibility of the production process.

[0005] To solve the above technical problems, the technical solution adopted by the utility model is as follows:

[0006] A reactor for directly preparing aminocapronitrile from cyclohexanone oxime includes a reaction tower. A feed inlet is provided at the top of the reaction tower, and a discharge outlet is provided at the bottom of the reaction tower. A support plate is arranged inside the reaction tower. The support plate divides the inner cavity of the reaction tower into a heat exchange reaction cavity and a normal reaction cavity. The heat exchange reaction cavity is located above the normal reaction cavity and is interconnected. A heat exchange reaction device is arranged in the heat exchange reaction cavity, and a fixed bed reactor is arranged in the normal reaction cavity.

[0007] In a preferred embodiment, the heat exchange reaction device includes a catalytic tube. The two ends of the catalytic tube are respectively connected to the feed inlet and the normal reaction cavity, and the catalytic tube is filled with a catalyst.

[0008] In a preferred embodiment, the outside of the catalytic tube is coated with a heat exchange tube. One end of the heat exchange tube is provided with a liquid inlet, and the other end of the heat exchange tube is provided with a liquid outlet. Both the liquid inlet and the liquid outlet are arranged outside the reaction tower and are connected to the coolant supply system.

[0009] In a preferred embodiment, a temperature sensor is provided at the end outlet of the catalytic tube.

[0010] In a preferred embodiment, the support plate is provided with mesh holes. The support plate is of a double-layer structure, and ceramic balls are filled between the support plates.

[0011] A reactor for directly preparing aminocapronitrile from cyclohexanone oxime has the following beneficial effects during actual use:

[0012] 1. The present utility model integrates the Beckmann rearrangement reaction and the ammoniation reaction in one reactor, avoiding the problem that these steps need to be completed in two reactors respectively in the traditional process, thus simplifying the overall process flow.

[0013] 2. By integrating the two reactions in one reactor, the present invention reduces the number of reactors required, thus reducing the equipment investment cost and improving the equipment utilization rate.

[0014] 3. The heat exchange reaction device can effectively increase the heat exchange reaction time and enable full heat exchange to meet the final requirements by setting the rotary catalytic tube and heat exchange tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The following further illustrates the present utility model in conjunction with the drawings and embodiments:

[0016] Figure 1 It is a plan sectional view of the overall structure of the present utility model;

[0017] Figure 2 It is a plan sectional view of the heat exchange reaction device of the present utility model.

[0018] In the figure: reaction tower 1, feed inlet 2, discharge outlet 3, heat exchange reaction chamber 4, support plate 5, ordinary reaction chamber 6, catalytic tube 7, heat exchange tube 8, liquid inlet 9, liquid outlet 10, catalyst 11, coolant 12, ceramic ball 13. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] As Figure 1As shown in the figure, a reactor for directly preparing 6-aminocapronitrile from cyclohexanone oxime includes a reaction tower 1. A feed inlet 2 is provided at the top of the reaction tower 1, and a discharge outlet 3 is provided at the bottom of the reaction tower 1. A support plate 5 is arranged inside the reaction tower 1. The support plate 5 divides the inner cavity of the reaction tower 1 into a heat exchange reaction cavity 4 and a general reaction cavity 6. The heat exchange reaction cavity 4 is located above the general reaction cavity 6 and is interconnected. A heat exchange reaction device is arranged in the heat exchange reaction cavity 4, and a fixed bed reactor is arranged in the general reaction cavity 6.

[0020] During the operation of the device, that is, the uniformly mixed materials enter the reaction tower 1 from the upper feed inlet 2 of the reaction tower 1, and after the reaction, they flow out from the bottom discharge outlet 3 for subsequent heat exchange. Since cyclohexanone oxime, acetonitrile, ammonia, and water in the reaction materials are all in the gas phase, a distributor is not arranged in the reaction tower 1.

[0021] The preferred solution is as Figure 2 shown. The heat exchange reaction device includes a catalytic tube 7. The two ends of the catalytic tube 7 are respectively connected to the feed inlet 2 and the general reaction cavity 6. The catalytic tube 7 is filled with a catalyst 11.

[0022] The reaction occurring in the catalytic tube 7 is as follows;

[0023] CHO(g)→CPL(g);

[0024] Hm = 164.7 kJ / mol (100 kPa, 298 K).

[0025] The preferred solution is as Figure 2 shown. The outside of the catalytic tube 7 is coated with a heat exchange tube 8. One end of the heat exchange tube 8 is provided with a liquid inlet 9, and the other end of the heat exchange tube 8 is provided with a liquid outlet 10. Both the liquid inlet 9 and the liquid outlet 10 are arranged outside the reaction tower 1.

[0026] During the operation of the device, the coolant 12 enters from the liquid inlet 9, absorbs the heat in the catalytic tube 7, and then is output from the liquid outlet 10 to achieve the heat exchange process.

[0027] The preferred solution is as Figure 1 shown. A temperature sensor is arranged at the end outlet of the catalytic tube 7 to always control the temperature of the material between 340 - 380 °C.

[0028] The preferred solution is as Figure 1 shown. The support plate 5 is provided with mesh holes. The support plate 5 is of a double-layer structure, and ceramic balls 13 are filled between the support plates 5. The ceramic balls 13 play a role in supporting and dispersing the material gas flow.

[0029] After the materials are fully reacted in the heat exchange reaction cavity 4, they enter the general reaction cavity 6. The ammoniation reaction formula of caprolactam in the general reaction cavity 6 is:

[0030] CPL(g) + NH3(g) → ACN + H2O(g);

[0031] Hm = 69.3 kJ / mol (100 kPa, 298 K);

[0032] This process is an endothermic reaction. The material after sufficient reaction is finally output from the discharge port 3. By setting multiple temperature monitoring points in the catalyst bed, the temperature change in the reactor can be monitored in real time. The reaction temperature is controlled at 340 - 380 °C, the reaction pressure is controlled at 0.1 - 0.3 MPa, and the ratio of cyclohexanone oxime: acetonitrile: ammonia in the raw material gas is 1:9:60. The liquid-phase feed space velocity of cyclohexanone oxime is 1 kg / (kgcat·h); under these conditions, after the reaction liquid is refined, the conversion rate of cyclohexanone oxime is 100%, and the yield of 6-aminocapronitrile can reach 86%.

Claims

1. A reactor for directly preparing 6 - aminocapronitrile from cyclohexanone oxime, comprising a reaction tower (1), characterized in that: A feed inlet (2) is provided at the top of the reaction tower (1), and a discharge outlet (3) is provided at the bottom of the reaction tower (1). A support plate (5) is arranged inside the reaction tower (1). The support plate (5) divides the inner cavity of the reaction tower (1) into a heat exchange reaction chamber (4) and a general reaction chamber (6). The heat exchange reaction chamber (4) is located above the general reaction chamber (6) and is interconnected. A heat exchange reaction device is arranged in the heat exchange reaction chamber (4), and a fixed bed reactor is arranged in the general reaction chamber (6).

2. The reactor for directly preparing 6 - aminocapronitrile from cyclohexanone oxime according to claim 1, wherein: The heat exchange reaction device includes a catalytic tube (7). The two ends of the catalytic tube (7) are respectively communicated with the feed inlet (2) and the general reaction chamber (6). A catalyst (11) is filled in the catalytic tube (7).

3. The reactor for directly preparing 6 - aminocapronitrile from cyclohexanone oxime according to claim 2, wherein: The outside of the catalytic tube (7) is coated with a heat exchange tube (8). One end of the heat exchange tube (8) is provided with a liquid inlet (9), and the other end of the heat exchange tube (8) is provided with a liquid outlet (10). Both the liquid inlet (9) and the liquid outlet (10) are arranged outside the reaction tower (1) and are communicated with a coolant supply system.

4. The reactor for directly preparing 6 - aminocapronitrile from cyclohexanone oxime according to claim 2, characterized in that: A temperature sensor is arranged at the end outlet of the catalytic tube (7).

5. The reactor for directly preparing 6 - aminocapronitrile from cyclohexanone oxime according to claim 1, characterized in that: The support plate (5) is provided with mesh holes. The support plate (5) is of a double-layer structure, and ceramic balls (13) are filled between the support plates (5).

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