System for co-production of cyclohexylamine and dicyclohexylamine from epsilon-caprolactone

Abstract

The utility model discloses a system for co-producing cyclohexylamine and dicyclohexylamine from epsilon-caprolactone, and relates to the technical field of preparation of cyclohexylamine and dicyclohexylamine. The device comprises a first preparation system and a second preparation system, and the first preparation system is used for preparing epsilon-caprolactone through dehydrogenation of 1, 6-hexanediol; the second preparation system is used for preparing cyclohexylamine and dicyclohexylamine; the second preparation system comprises an aniline mixing tank, a hydrogen mixing tank and a first gasification furnace, the first gasification furnace is sequentially connected with a first flash tank, a hydrogenation reactor, a second flash tank, a tar separation tower, a cyclohexylamine product tower and a raw material recovery tower, and the hydrogen mixing tank is connected with the first preparation system; and hydrogen generated in the dehydrogenation section through the first preparation system enters the hydrogen mixing tank. According to the device disclosed by the utility model, hydrogen generated by preparing epsilon-caprolactone through dehydrogenation of 1, 6-hexanediol is utilized and applied to the second preparation system, so that efficient utilization of energy is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of the preparation of cyclohexylamine and dicyclohexylamine, and particularly relates to a system for co-producing ε-caprolactone, cyclohexylamine and dicyclohexylamine. Background Art

[0002] Cyclohexylamine, also known as hexahydroaniline and aminocyclohexane, is a colorless transparent liquid with a strong fishy and stinky amine smell, and can be miscible with water and common organic solvents. It is an important organic chemical raw material and fine chemical intermediate, and is mainly used in rubber auxiliaries, food additives, anti-corrosion, papermaking, plastic processing and textile industries. The preparation method of dicyclohexylamine is to use aniline as a raw material, and under the presence of a catalyst, high-temperature and high-pressure hydrogenation is carried out to obtain dicyclohexylamine. Dicyclohexylamine is commonly used in organic synthesis, and is also used as an insecticide, an acidic gas absorbent and a steel rust inhibitor; it is also used as an extractant for natural products and organic synthesis, and an acidic gas absorbent; the salts formed by it and fatty acids and sulfuric acid have excellent surface active effects and are used in the printing and fiber industries; the complexes formed by it and metals are used as catalysts for coatings and inks.

[0003] A large amount of hydrogen is by-produced in the dehydrogenation of 1,6-hexanediol to prepare ε-caprolactone, and hydrogen is also used as a carrier gas during the dehydrogenation reaction. The conventional treatment method for these remaining hydrogen is to carry out methanation treatment and then continue to use it or directly discharge it, and the hydrogen utilization rate is low. How to reasonably utilize the large amount of hydrogen generated during the preparation of ε-caprolactone is a technical problem concerned by researchers in this field. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a system for co-producing ε-caprolactone, cyclohexylamine and dicyclohexylamine, which uses the large amount of hydrogen generated during the preparation of ε-caprolactone for the hydrogenation of aniline, and aniline is catalytically hydrogenated to synthesize cyclohexylamine, and dicyclohexylamine is co-produced. The dehydrogenation reaction is endothermic and requires a large amount of heat, while the hydrogenation is an exothermic reaction. The energy involved in the two reactions is thermally coupled to achieve efficient energy utilization, and at the same time, the energy of other heat exchange units can be saved by using these two reactors.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A system for co-producing ε-caprolactone, cyclohexylamine and dicyclohexylamine, which includes a first preparation system and a second preparation system. The first preparation system is to prepare ε-caprolactone by dehydrogenating 1,6-hexanediol; the second preparation system is used to prepare cyclohexylamine and dicyclohexylamine.

[0007] The described second preparation system includes an aniline mixing tank, a hydrogen mixing tank, and a first gasifier. The first gasifier is sequentially connected to a first flash tank, a hydrogenation reactor, a second flash tank, a tar separation tower, a cyclohexylamine product tower, and a raw material recovery tower. The hydrogen mixing tank is connected to the first preparation system, and the first preparation system supplies the hydrogen generated in the dehydrogenation section to the hydrogen mixing tank;

[0008] The aniline mixing tank and the hydrogen mixing tank respectively supply aniline and hydrogen to the first gasifier;

[0009] The mixture in the first gasifier enters the first flash tank. The first flash tank is used to separate the mixture. The unvaporized liquid in the mixture is discharged from the bottom of the first flash tank, and the gas in the mixture enters the hydrogenation reactor through the outlet at the top of the first flash tank;

[0010] The material in the hydrogenation reactor enters the second flash tank after the hydrogenation reaction. The hydrogen removed through the second flash tank is discharged through the outlet of the second flash tank and enters the hydrogen mixing tank; the remaining material in the second flash tank enters the tar separation tower. After separation in the tar separation tower, the top product is cyclohexylamine, aniline, and dicyclohexylamine, and the bottom product is tar;

[0011] The top product enters the cyclohexylamine product tower to separate cyclohexylamine;

[0012] Aniline and dicyclohexylamine enter the raw material recovery tower. Dicyclohexylamine is discharged from the bottom of the raw material recovery tower, and aniline is recycled to the aniline mixing tank.

[0013] In the above-mentioned system for co-producing ε-caprolactone, cyclohexylamine, and dicyclohexylamine, the first preparation system includes a sequentially connected hexanediol mixing tank, a second gasifier, a third flash tank, a dehydrogenation reactor, a fourth flash tank, a light component removal tower, a product separation tower, and a raw material separation tower. The hexanediol mixing tank is used to supply hexanediol to the second gasifier. The mixture in the second gasifier enters the third flash tank. The third flash tank is used to remove the unvaporized liquid material. The dehydrogenation reactor is used to supply the dehydrogenated material to the fourth flash tank. The fourth flash tank is used to remove hydrogen and send the hydrogen into the hydrogen mixing tank. The light component removal tower is used to remove the light components in the material. The bottom of the light component removal tower is the product material after removing the light components. The product material enters the product separation tower and enters the raw material separation tower from the bottom of the product separation tower after separation.

[0014] In the above-mentioned system for co-producing ε-caprolactone, cyclohexylamine and dicyclohexylamine, filters are provided between the hydrogenation reactor and the second flash tank, between the hexanediol mixing tank and the second gasifier, and between the dehydrogenation reactor and the fourth flash tank.

[0015] In the above-mentioned system for co-producing ε-caprolactone, cyclohexylamine and dicyclohexylamine, the temperature in the first gasifier is 140 - 180°C, the reaction temperature of the hydrogenation reactor is 140 - 180°C, and the pressure is 0.03 - 0.06 MPa.

[0016] In the above-mentioned system for co-producing ε-caprolactone, cyclohexylamine and dicyclohexylamine, the top temperature of the tar separation column is 90 - 140°C, and the pressure is 0.05 - 0.2 MPa; the top temperature of the cyclohexylamine product column is 140 - 180°C, and the pressure is 0.05 - 0.2 MPa; the top temperature of the raw material recovery column is 110 - 150°C, and the pressure is 0.03 - 0.07 MPa.

[0017] In the above-mentioned system for co-producing ε-caprolactone, cyclohexylamine and dicyclohexylamine, the unvaporized liquid in the mixture is discharged from the bottom of the first flash tank and enters the aniline mixing tank connected to the first flash tank.

[0018] In the above-mentioned system for co-producing ε-caprolactone, cyclohexylamine and dicyclohexylamine, the 1,6-hexanediol recovered by the raw material separation column enters the hexanediol mixing tank connected to the raw material separation column.

[0019] Compared with the prior art, the present utility model brings the following beneficial technical effects:

[0020] The present utility model provides a system for co-producing ε-caprolactone, cyclohexylamine and dicyclohexylamine, which includes a first preparation system and a second preparation system. The first preparation system dehydrogenates 1,6-hexanediol to prepare ε-caprolactone; the second preparation system is used to prepare cyclohexylamine and dicyclohexylamine; hydrogen is provided to the second preparation system by the first preparation system. In the second preparation system, aniline is mixed with hydrogen and successively passes through equipment such as gasification, flash evaporation, and dehydrogenation, and finally cyclohexylamine and dicyclohexylamine can be prepared.

[0021] The system of the present utility model realizes the efficient preparation of ε-caprolactone and co-produces cyclohexylamine and dicyclohexylamine. This system is a continuous production system with high atomic utilization rate and less three wastes, and at the same time, combined with thermal coupling, it can achieve lower product energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The following further describes the present utility model with reference to the drawings:

[0023] Figure 1 It is a schematic structural diagram of the second preparation system of the present utility model;

[0024] Figure 2 It is a schematic structural diagram of the system of the present utility model;

[0025] In the figure: 1, aniline mixing tank; 2, hydrogen mixing tank; 3, first gasifier; 4, first flash tank; 5, hydrogenation reactor; 6, second flash tank; 7, tar separation column; 8, cyclohexylamine product column; 9, raw material recovery column; 10, hexanediol mixing tank; 11, second gasifier; 12, third flash tank; 13, dehydrogenation reactor; 14, fourth flash tank; 15, light component removal column; 16, product separation column; 17, raw material separation column. Specific embodiments

[0026] The present utility model provides a system for co-producing ε-caprolactone, cyclohexylamine and dicyclohexylamine. In order to make the advantages and technical solutions of the present utility model clearer and more definite, the following further describes the present utility model with specific embodiments.

[0027] The main technical concept of the present utility model is as follows: A large amount of hydrogen is by-produced during the dehydrogenation of 1,6-hexanediol to prepare ε-caprolactone, and hydrogen carrier gas is also used during the dehydrogenation reaction. Currently, in the prior art, the conventional treatment method for these remaining hydrogen is to carry out methanation treatment and then continue to use it or directly discharge it, resulting in low hydrogen utilization rate. The present utility model uses the hydrogen by-produced in the dehydrogenation section for aniline hydrogenation, and aniline is catalytically hydrogenated to synthesize cyclohexylamine, co-producing dicyclohexylamine. The dehydrogenation reaction is endothermic and requires a large amount of heat, while the hydrogenation is an exothermic reaction. The energy involved in these two reactions is thermally coupled to achieve efficient energy utilization. At the same time, the energy of other heat exchange units can also be saved by using these two reactors.

[0028] As Figure 2 shown, the system for co-producing ε-caprolactone, cyclohexylamine and dicyclohexylamine of the present utility model includes a first preparation system and a second preparation system. The first preparation system is to dehydrogenate 1,6-hexanediol to prepare ε-caprolactone; the second preparation system is used to prepare cyclohexylamine and dicyclohexylamine. The present utility model creatively couples the two preparation systems and uses the hydrogen in the first preparation system in the second preparation system, and finally prepares cyclohexylamine and dicyclohexylamine.

[0029] The above-mentioned first preparation system includes a 1,2-hexanediol mixing tank 10, a second gasifier 11, a third flash tank 12, a dehydrogenation reactor 13, a fourth flash tank 14, a light component removal tower 15, a product separation tower 16, and a raw material separation tower 17, which are connected in sequence. In the 1,2-hexanediol mixing tank, there is raw material 1,2-hexanediol and recycled 1,2-hexanediol. After mixing the recycled one with the original in the mixing tank, they are used as raw materials for preparing ε-caprolactone. A filter is preferably connected between the 1,2-hexanediol mixing tank 10 and the second gasifier. The mixed raw materials are preliminarily filtered through the filter and then enter the second gasifier 11. Fresh hydrogen gasifies with the filtered 1,2-hexanediol in the second gasifier. The resulting gasified material is passed through the third flash tank to remove the ungasified liquid material and then enters the dehydrogenation reactor 13.

[0030] After the reaction in the dehydrogenation reactor 13, it enters the fourth flash tank 14 to further remove hydrogen gas. At this time, the removed hydrogen gas is used in the second preparation system. Therefore, the fourth flash tank 14 is connected to the second preparation system to supply hydrogen gas to it.

[0031] The remaining material after passing through the fourth flash tank 14 passes through the light component removal tower 15 to remove the light components in the material. The light components are at the top of the tower, and the material containing the product is at the bottom of the tower. After the feed removes the light components, the bottom product enters the product separation tower 16. The product separation tower 16 is a packed tower. In this packed tower, the bottom is the material containing polymer and 1,6-hexanediol. After separating the product, the bottom material enters the raw material separation tower. The raw material separation tower is a packed tower. The top of the tower is ε-caprolactone, and the bottom is polymer. After passing through the raw material recovery tower, the ε-caprolactone raw material at the top of the tower is mixed with fresh ε-caprolactone and enters the dehydrogenation process. The polymer at the bottom of the tower is collected and further processed and sold.

[0032] As Figure 1 shown, the above-mentioned second preparation system includes an aniline mixing tank 1, a hydrogen mixing tank 2, and a first gasifier 3. The first gasifier is connected to a first flash tank 4, a hydrogenation reactor 5, a second flash tank 6, a tar separation tower 7, a cyclohexylamine product tower 8, and a raw material recovery tower 9 in sequence. The hydrogen mixing tank is connected to the first preparation system, and the hydrogen gas generated in the dehydrogenation section of the first preparation system enters the hydrogen mixing tank. In this way, the hydrogen gas generated by the first preparation system can be utilized by the second preparation system.

[0033] The described aniline mixing tank and hydrogen mixing tank respectively supply aniline and hydrogen to the first gasifier, and the molar ratio of hydrogen to aniline is 5 - 15:1; the mixture in the first gasifier enters the described first flash tank, and the first flash tank is used for separating the mixture. The unvaporized liquid is removed in the first flash tank. The unvaporized liquid in the mixture is discharged from the bottom of the first flash tank, and the gas in the mixture enters the described hydrogenation reactor through the outlet at the top of the first flash tank. After mixing, the material temperature is 140 - 180°C and the pressure is 0.03 - 0.06 MPa.

[0034] Preferably, a filter is arranged between the hydrogenation reactor and the second flash tank. After the material in the hydrogenation reactor undergoes a hydrogenation reaction, it enters the second flash tank after being filtered by the filter. The hydrogen removed by the second flash tank is discharged through the outlet of the second flash tank and enters the described hydrogen mixing tank; the remaining material in the second flash tank enters the described tar separation tower. After being separated by the tar separation tower, the top product is cyclohexylamine, aniline and dicyclohexylamine, and the bottom product is tar; in the tar separation tower, the top temperature is 90 - 140°C and the pressure is 0.05 - 0.2 MPa. The top product is cyclohexylamine, aniline and dicyclohexylamine, and the top product enters the described cyclohexylamine product tower to separate cyclohexylamine.

[0035] Aniline and dicyclohexylamine enter the described raw material recovery tower. Dicyclohexylamine is discharged from the bottom of the raw material recovery tower, and aniline is recycled to the described aniline mixing tank.

[0036] The following is a description of the usage method of the above system in combination with specific embodiments.

[0037] Example 1:

[0038] Use the above system for co-producing ε-caprolactone, cyclohexylamine and dicyclohexylamine to prepare cyclohexylamine and dicyclohexylamine. The specific steps are as follows:

[0039] Step 1: Mix the recycled 1,6 - hexanediol with the 1,6 - hexanediol in the 1,6 - hexanediol mixing tank, conduct preliminary filtration after mixing, and then enter the first gasifier;

[0040] Step 2: Dehydrogenation material mixing: The filtered 1,6 - hexanediol and fresh hydrogen respectively enter the superheater for gasification. The molar ratio of hydrogen to 1,6 - hexanediol is 3:1 - 10:1, and the temperature of the gasified material is 100 - 300°C. After mixing and gasification, the raw material for dehydrogenation is obtained. The gasified material is passed through the third flash tank to remove the unvaporized liquid material therein, and then enters the dehydrogenation reactor;

[0041] Step 3. Dehydrogenation reaction: The mixed materials enter the dehydrogenation reactor for reaction. The reaction temperature is 100 - 300 °C, the pressure is 0 - 0.4 MPa, and the feed space velocity is 0.5 - 3.5 / h. The materials after the reaction enter the next process;

[0042] Step 4. Pretreatment: After the dehydrogenation reaction, the materials pass through a filter to remove the solid impurities containing the catalyst, and then enter the fourth flash tank to remove hydrogen. The hydrogen enters the hydrogenation section, and the remaining materials enter the rectification process of the dehydrogenation section;

[0043] Step 5. Light component separation: First, it passes through a light component removal tower at atmospheric pressure. The top temperature of the tower is 80 - 150 °C to remove the light components in the materials. The top of the tower is the light components, and the bottom of the tower is the materials containing the product. After the light components are removed from the feed, the bottom product of the tower enters the product separation tower;

[0044] Step 6. Product separation: The product separation tower is a packed tower with a pressure of 200 - 1000 Pa and a top temperature of 100 - 140 °C. The top of the product tower is the product, and the bottom is the materials containing the polymer and 1,6 - hexanediol. After the product is separated, the bottom materials enter the raw material recovery tower;

[0045] Step 7. Raw material separation: The raw material recovery tower is a packed tower with a pressure of 1000 - 2000 Pa and a top temperature of 120 - 170 °C. The top of the tower is ε - caprolactone, and the bottom is the polymer. After passing through the raw material recovery tower, the ε - caprolactone raw material at the top is mixed with the fresh ε - caprolactone and enters the dehydrogenation process. The polymer at the bottom is collected and further processed and sold;

[0046] Step 8. Hydrogen mixing: The hydrogen removed in the dehydrogenation section is mixed with the hydrogen recovered in the hydrogenation section and then enters the first gasifier;

[0047] Step 9. Aniline premixing: Fresh aniline, incompletely vaporized aniline, and recovered aniline are premixed and then enter the first gasifier for gasification. The gasification temperature is 140 - 180 °C;

[0048] Step 10. Hydrogenation feed mixing: The mixed aniline and the mixed hydrogen enter the first gasifier at one time. The molar ratio of hydrogen to aniline is 5:1 - 15:1, and then enter the first flash tank. The unvaporized liquid is removed in the first flash tank, and the gas feed enters the hydrogenation reactor for reaction. The temperature of the mixed materials after mixing is 140 - 180 °C, and the pressure is 0.03 - 0.06 MPa;

[0049] Step 11. Hydrogenation reaction: The mixed materials enter the hydrogenation reactor for reaction. The reaction temperature is 140 - 180 °C, the pressure is 0.03 - 0.06 MPa, and the materials after the reaction enter the next process;

[0050] Step Twelve, Pretreatment: After the hydrogenation reaction, the material passes through a filter to remove the solid impurities containing the catalyst, and then enters the second flash tank to remove hydrogen. The hydrogen is recycled and reused, and the remaining material enters the rectification process of the hydrogenation section;

[0051] Step Thirteen, Tar Separation: The material from the hydrogenation pretreatment enters the tar removal tower. The top temperature of the tower is 90 - 140 °C, and the pressure is 0.05 - 0.2 MPa. The top products are cyclohexylamine, aniline, and dicyclohexylamine, and then enter the product separation tower. The bottom product is tar, which is treated harmlessly;

[0052] Step Fourteen, Product Separation: The top temperature of the cyclohexylamine product tower is 140 - 180 °C, and the pressure is 0.05 - 0.2 MPa. The top product is cyclohexylamine, which is taken out as a product. The bottom product is a mixture of aniline and dicyclohexylamine and enters the raw material recovery tower.

[0053] Step Fifteen, Raw Material Separation: The top temperature of the raw material recovery tower is 110 - 150 °C, and the pressure is 0.03 - 0.07 MPa. The top product is aniline, which is recycled and used. The bottom product is the by-product dicyclohexylamine.

[0054] The parts not described in this utility model can be realized by referring to the prior art.

[0055] It should be noted that any equivalent method or obvious variant method made by those skilled in the art under the teaching of this specification should be within the protection scope of this utility model.

Claims

1. A system for co-producing ε-caprolactone, cyclohexylamine and dicyclohexylamine, characterized in that, It includes a first preparation system and a second preparation system. The first preparation system dehydrogenates 1,6 - hexanediol to prepare ε - caprolactone; the second preparation system is used to prepare cyclohexylamine and dicyclohexylamine. The second preparation system includes an aniline mixing tank, a hydrogen mixing tank and a first gasifier, which is successively connected to a first flash tank, a hydrogenation reactor, a second flash tank, a tar separation tower, a cyclohexylamine product tower and a raw material recovery tower. The hydrogen mixing tank is connected to the first preparation system, and the first preparation system supplies the hydrogen generated in the dehydrogenation section to the hydrogen mixing tank. The aniline mixing tank and the hydrogen mixing tank respectively supply aniline and hydrogen to the first gasifier. The mixture in the first gasifier enters the first flash tank, which is used to separate the mixture. The unvaporized liquid in the mixture is discharged from the bottom of the first flash tank, and the gas in the mixture enters the hydrogenation reactor through the outlet at the top of the first flash tank. The material in the hydrogenation reactor enters the second flash tank after the hydrogenation reaction. The hydrogen removed by the second flash tank is discharged through the outlet of the second flash tank and enters the hydrogen mixing tank. The remaining material in the second flash tank enters the tar separation tower. After separation in the tar separation tower, the top product is cyclohexylamine, aniline and dicyclohexylamine, and the bottom product is tar. The top product enters the cyclohexylamine product tower to separate cyclohexylamine. Aniline and dicyclohexylamine enter the raw material recovery tower. Dicyclohexylamine is discharged from the bottom of the raw material recovery tower, and aniline is recycled to the aniline mixing tank.

2. The system for co-producing ε-caprolactone, cyclohexylamine and dicyclohexylamine according to claim 1, characterized in that: The first preparation system includes a hexanediol mixing tank, a second gasifier, a third flash tank, a dehydrogenation reactor, a fourth flash tank, a light component removal tower, a product separation tower and a raw material separation tower connected in sequence. The hexanediol mixing tank is used to supply hexanediol to the second gasifier. The mixture in the second gasifier enters the third flash tank, which is used to remove the unvaporized liquid material. The dehydrogenation reactor is used to supply the dehydrogenated material to the fourth flash tank. The fourth flash tank is used to remove hydrogen and send the hydrogen into the hydrogen mixing tank. The light component removal tower is used to remove the light components in the material. The bottom of the light component removal tower is the product material after removing the light components. The product material enters the product separation tower and then enters the raw material separation tower from the bottom of the product separation tower after separation.

3. The system for co-producing ε-caprolactone, cyclohexylamine and dicyclohexylamine according to claim 2, wherein: Filters are provided between the hydrogenation reactor and the second flash tank, between the hexanediol mixing tank and the second gasifier, and between the dehydrogenation reactor and the fourth flash tank.

4. The system for co-producing ε-caprolactone, cyclohexylamine and dicyclohexylamine according to claim 2, wherein: The temperature in the first gasifier is 140 - 180 °C, the reaction temperature of the hydrogenation reactor is 140 - 180 °C, and the pressure is 0.03 - 0.06 MPa.

5. The system for co-producing ε-caprolactone, cyclohexylamine and dicyclohexylamine according to claim 2, wherein: The top temperature of the described tar separation column is 90 - 140 °C, and the pressure is 0.05 - 0.2 MPa; the top temperature of the cyclohexylamine product column is 140 - 180 °C, and the pressure is 0.05 - 0.2 MPa; the top temperature of the described raw material recovery column is 110 - 150 °C, and the pressure is 0.03 - 0.07 MPa.

6. The system for co-producing ε-caprolactone, cyclohexylamine and dicyclohexylamine according to claim 1, characterized in that: The unvaporized liquid in the mixture is discharged from the bottom of the first flash tank and enters the aniline mixing tank connected to the first flash tank.

7. A system for co-producing ε-caprolactone, cyclohexylamine and dicyclohexylamine according to claim 2, characterized in that: The 1,6 - hexanediol recovered by the described raw material separation column enters the hexanediol mixing tank connected to the raw material separation column.

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