Heat recycling system for preparing 6-aminocapronitrile reaction liquid from cyclohexanone oxime

Abstract

The utility model relates to a heat recycling system, in particular to a heat recycling system for a 6-aminocapronitrile reaction solution prepared by ammoniating cyclohexanone oxime, which comprises an ammoniation reactor, an ammonia gas heat exchanger, an ammoniation product tower and a coarse separation tower. The heat of the reaction liquid flowing out of the ammoniation reactor firstly returns to the ammonia gas heat exchanger of the previous working section to be utilized to preliminarily heat the raw material ammonia gas, then the residual heat sequentially enters the tower kettle reboiler of the ammoniation product tower and the reboiler of the coarse separation tower to be utilized, and finally enters the separation system to be refined. According to the utility model, the heat of the ammoniation reaction liquid is fully recycled, so that the energy recycling is realized, the waste is avoided, the energy is saved, and the production cost is reduced.

Description

Technical Field

[0001] The utility model relates to a heat recovery system, in particular to a heat recovery system for a reaction liquid of preparing 6-aminocapronitrile from cyclohexanone oxime. Background Art

[0002] 6-Aminocapronitrile is an important organic compound and an intermediate in the preparation of hexamethylenediamine from caprolactam or cyclohexanone oxime. In recent years, with the rapid development of the downstream market for hexamethylenediamine and the widespread application of chemical fiber fabrics and plastic products in a wide range of fields, including textiles, papermaking, electronics, automotive, and aerospace, the market demand for nylon 66 has further increased, driving an increase in the demand for hexamethylenediamine. Currently, only a few companies in my country, such as Henan Shenma Group and Xuyang Group, have industrialized production facilities, with a total capacity of approximately 900,000 tons and approximately 2 million tons of capacity under planning. Overall, the hexamethylenediamine market in my country currently exhibits a supply shortage, and there is broad room for future development.

[0003] The temperature of the reaction materials coming out of the reactor after the amination reaction is 400°C. If this heat can be fully utilized, it will not only save energy and reduce costs, but also avoid environmental pollution caused by direct discharge of heat into the environment. Utility Model Content

[0004] The utility model provides a heat recycling system for a reaction liquid of cyclohexanone oxime to 6-aminocapronitrile. The method realizes energy recycling, avoids waste, saves energy and reduces production costs.

[0005] The technical solution of this utility model:

[0006] A heat recovery system for a reaction liquid from cyclohexanone oxime to 6-aminocapronitrile comprises an amination reactor, an ammonia heat exchanger, an amination product tower, and a crude fraction tower, wherein the material outlet of the amination reactor is connected to the shell-side material inlet of the ammonia heat exchanger;

[0007] The cyclohexanone oxime pipeline is connected to the cyclohexanone oxime evaporator, the cyclohexanone oxime evaporator is connected to the mixer, and the mixer is connected to the ammonia heat exchanger;

[0008] The shell-side material outlet of the ammonia heat exchanger is connected to the heating medium inlet of the ammonia product tower, the heating medium outlet of the ammonia product tower is connected to the heating medium inlet of the coarse fraction tower, and the heating medium outlet of the coarse fraction tower is connected to the feed inlet of the gas phase circulation tower.

[0009] Both the ammoniated product tower and the coarse fraction tower are equipped with stainless steel heating coils. The heating medium flows through the stainless steel coils to provide the required heat source for the distillation tower. The diameter of the coils in the coarse fraction tower is 20-30mm; the diameter of the coils in the ammoniated product tower is 20-30mm. The highest point of the coils does not exceed half the height of the kettle, and the pipes are arranged horizontally according to the kettle reboiler.

[0010] The bottom of the gas phase circulation tower is connected to the coarse fraction tower, and the top of the gas phase circulation tower is connected to the material outlet of the amination reactor through the circulation compressor outlet buffer tank, the circulation compressor, the circulation compressor inlet buffer tank in sequence.

[0011] The bottom of the coarse fraction tower is connected to the ammonia product tower via a pipeline.

[0012] The top of the gas phase circulation tower is connected to the gas phase circulation tower reflux tank via a pipeline, and the top of the coarse fractionation tower is connected to the coarse fractionation tower reflux tank via a pipeline.

[0013] The top of the amination product tower is connected to the amination product tower reflux tank via a pipeline, and the amination product tower reflux tank is connected to the 6-aminocapronitrile product tank via a pipeline.

[0014] The ammonia heat exchanger is connected to the mixer.

[0015] After the amination reaction, the reaction materials exiting the reactor are first returned to the shell side of the ammonia heat exchanger, where they exchange heat with the raw ammonia gas for initial heating. They then flow into the heating coils of the ammonia product column, providing heat for the column. After exiting the ammonia product column, they flow into the heating coils of the crude fraction column kettle, providing heat for the crude fraction column. Finally, they enter the distillation column from the middle of the gas-phase circulation column for subsequent separation and refining. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a heat recycling diagram of the present utility model.

[0017] In the figure, 1 is the material outlet of the amination reactor, 2 is the cyclohexanone oxime pipeline, 3 is the ammonia heat exchanger, 4 is the circulating compressor inlet buffer tank, 5 is the circulating compressor, 6 is the circulating compressor outlet buffer tank, 7 is the ammonia heater, 8 is the cyclohexanone oxime evaporator, 9 is the mixer, 10 is the amination reactor, 11 is the gas phase circulation tower, 12 is the gas phase circulation tower reflux tank, 13 is the crude fraction tower, 14 is the crude fraction tower reflux tank, 15 is the amination product tower, 16 is the amination product tower reflux tank, and 17 is the 6-aminocapronitrile product tank. DETAILED DESCRIPTION

[0018] The heat recovery system in the embodiment of the present application will be clearly and completely described below in conjunction with the drawings in the embodiment of the present application.

[0019] A heat recovery system for a reaction liquid from cyclohexanone oxime to 6-aminocapronitrile comprises an amination reactor, an ammonia heat exchanger, an amination product tower, and a crude fraction tower, wherein a material outlet 1 of the amination reactor is connected to a shell-side material inlet of an ammonia heat exchanger 3;

[0020] The cyclohexanone oxime pipeline 2 is connected to the cyclohexanone oxime evaporator 8, the cyclohexanone oxime evaporator 8 is connected to the mixer 9, and the mixer 9 is connected to the ammonia heat exchanger 3; in order to minimize the heat loss of the reaction liquid, the outside of the ammonia heat exchanger is insulated with rock wool, and the thickness of the rock wool is 100.00 mm.

[0021] The shell side material outlet of the ammonia heat exchanger 3 is connected to the heating medium inlet of the ammoniated product tower 15, the heating medium outlet of the ammoniated product tower 15 is connected to the heating medium inlet of the coarse fraction tower 13, and the heating medium outlet of the coarse fraction tower 13 is connected to the feed port of the gas phase circulation tower 11.

[0022] Both the ammoniated product tower 15 and the crude fraction tower 13 are equipped with stainless steel heating coils. The heating medium flows through the stainless steel coils to provide the required heat source for the distillation tower. The diameter of the coil in the crude fraction tower 13 is 30 mm, and its heat exchange area is 7.3 m 2 The diameter of the coil in the ammonia product tower 15 is 30 mm, and its heat exchange area is 1.6 m 2 The highest point of the coil does not exceed half of the kettle height, and the pipes are arranged horizontally according to the kettle reboiler.

[0023] The bottom of the gas phase circulation tower 11 is connected to the coarse fraction tower 13, and the top of the gas phase circulation tower 11 is connected to the material outlet 1 of the amination reactor via the circulation compressor outlet buffer tank 6, the circulation compressor 5, and the circulation compressor inlet buffer tank 4 in sequence.

[0024] The bottom of the crude fraction tower 13 is connected to the amination product tower 15 via a pipeline.

[0025] The top of the gas phase circulation tower 11 is connected to the gas phase circulation tower reflux tank 12 via a pipeline, and the top of the coarse fraction tower 13 is connected to the coarse fraction tower reflux tank 14 via a pipeline.

[0026] The top of the amination product tower 15 is connected to the amination product tower reflux tank 16 via a pipeline, and the amination product tower reflux tank 16 is connected to the 6-aminocapronitrile product tank 17 via a pipeline.

[0027] The ammonia heat exchanger 3 is connected to the mixer 9 .

[0028] The process carried out using the technical solution of the present invention is as follows:

[0029] 1. After the amination reaction, the reaction materials coming out of the reactor are first returned to the shell side of the ammonia heat exchanger to exchange heat with the raw ammonia gas, initially heating the raw ammonia gas. At this time, the temperature of the reaction materials drops from 420°C to 337°C, and the temperature of the raw ammonia gas is heated from 100°C to 230°C.

[0030] 2. It then flows into the heating coil of the ammoniated product tower to provide the required heat for the ammoniated product tower. At this time, the temperature of the reaction material drops from 335°C to 248°C.

[0031] 3. After flowing out from the amination product tower, it enters the heating coil of the crude fraction tower kettle to provide heat for the crude fraction tower. At this time, the temperature of the reaction material drops from 248℃ to 160℃.

[0032] 4. Finally, it enters the distillation tower from the middle of the gas phase circulation tower for subsequent separation and purification.

Claims

1. A heat recovery system for a reaction solution of cyclohexanone oxime to 6-aminocapronitrile, characterized in that: It includes an ammonia reactor, an ammonia heat exchanger, an ammonia product tower and a coarse fraction tower, wherein the material outlet (1) of the ammonia reactor is connected to the shell-side material inlet of the ammonia heat exchanger (3); The cyclohexanone oxime pipeline (2) is connected to the cyclohexanone oxime evaporator (8), the cyclohexanone oxime evaporator (8) is connected to the mixer (9), and the mixer (9) is connected to the ammonia heat exchanger (3); The shell-side material outlet of the ammonia heat exchanger (3) is connected to the heating medium inlet of the ammonia product tower (15), the heating medium outlet of the ammonia product tower (15) is connected to the heating medium inlet of the coarse fraction tower (13), and the heating medium outlet of the coarse fraction tower (13) is connected to the feed port of the gas phase circulation tower (11).

2. The heat recovery system for the reaction liquid of cyclohexanone oxime to 6-aminocapronitrile according to claim 1, characterized in that: Both the ammoniated product tower (15) and the crude fraction tower (13) are equipped with stainless steel heating coils. The heating medium flows through the stainless steel coils to provide the required heat source for the distillation tower. The diameter of the coils in the crude fraction tower (13) is 20-30 mm. The diameter of the coils in the ammoniated product tower (15) is 20-30 mm. The highest point of the coils does not exceed half the height of the kettle, and the pipes are arranged horizontally according to the kettle reboiler.

3. The heat recovery system for the reaction liquid of cyclohexanone oxime to 6-aminocapronitrile according to claim 1, characterized in that: The bottom of the gas phase circulation tower (11) is connected to the coarse fraction tower (13), and the top of the gas phase circulation tower (11) is connected to the material outlet (1) of the amination reactor via the circulation compressor outlet buffer tank (6), the circulation compressor (5), and the circulation compressor inlet buffer tank (4) in sequence.

4. The heat recovery system for the reaction liquid of cyclohexanone oxime to 6-aminocapronitrile according to claim 1, characterized in that: The bottom of the coarse fraction tower (13) is connected to the ammoniated product tower (15) via a pipeline.

5. The heat recovery system for the reaction liquid of cyclohexanone oxime to 6-aminocapronitrile according to claim 1, characterized in that: The top of the gas phase circulation tower (11) is connected to the gas phase circulation tower reflux tank (12) via a pipeline, and the top of the coarse fraction tower (13) is connected to the coarse fraction tower reflux tank (14) via a pipeline.

6. The heat recovery system for the reaction liquid of cyclohexanone oxime to 6-aminocapronitrile according to claim 1, characterized in that: The top of the amination product tower (15) is connected to the amination product tower reflux tank (16) via a pipeline, and the amination product tower reflux tank (16) is connected to the 6-aminocapronitrile product tank (17) via a pipeline.

7. The heat recovery system for the reaction liquid of cyclohexanone oxime to 6-aminocapronitrile according to claim 1, characterized in that: The ammonia heat exchanger (3) is connected to the mixer (9).

Images