A co-production unit for aniline and cyclohexylamine

Abstract

This invention discloses a co-production device for aniline and cyclohexylamine, comprising an aniline tail gas treatment unit, a hydrogenation reaction unit, and a product refining unit. The aniline tail gas treatment unit removes liquid organic matter and catalyst particles from the aniline tail gas and separates hydrogen and aniline. The hydrogenation reaction unit hydrogenates aniline and substandard aniline in the aniline tail gas to obtain a mixture of cyclohexylamine and dicyclohexylamine. The mixture is then purified by the product refining unit to remove low-boiling-point substances such as cyclohexane, cyclohexanol, and water, yielding the products cyclohexylamine and dicyclohexylamine. This invention fully utilizes aniline tail gas resources and substandard aniline, reducing waste treatment costs. It not only improves product efficiency but also reduces environmental pollution, resulting in significant economic and social benefits.

Description

Technical Field

[0001] This invention relates to the field of cyclohexylamine preparation technology, specifically to an apparatus for the co-production of aniline and cyclohexylamine. Background Technology

[0002] The industrial production of aniline began in 1857, initially using the nitrobenzene iron powder reduction method. However, this method suffered from drawbacks such as large equipment requirements, severe corrosion, high iron powder consumption, and significant pollution from waste. It was gradually replaced by the advanced nitrobenzene catalytic hydrogenation method after the 1950s. In 1962, the phenol amination method was successfully developed, and industrial production was achieved in 1970. Currently, aniline production worldwide is mainly based on the nitrobenzene catalytic hydrogenation method, accounting for approximately 85% of total aniline production capacity. The tail gas from nitrobenzene catalytic hydrogenation production plants contains a large amount of hydrogen and a small amount of aniline vapor and other organic matter. Common methods for treating this organic waste gas include activated carbon adsorption, condensation, and combustion. Activated carbon adsorption has high operating costs; condensation is suitable for high-concentration organic waste gas, but its treatment efficiency is low for low-concentration organic waste gas; combustion treats nitrogen-containing organic waste gas, producing nitrogen oxides and causing secondary pollution. In addition, the aniline in the aniline production unit that exceeds the standard for light components and the aniline in the top discharge of the light component removal tower have low aniline content and contain other components such as cyclohexanol, cyclohexane, phenol, and cyclohexylamine. These components need to be further separated and purified or sold at a low price, resulting in low economic benefits.

[0003] Cyclohexylamine and dicyclohexylamine, as important organic chemical raw materials and intermediates for fine chemical products, are widely used in industries such as rubber additives, food additives, preservatives, papermaking, plastics processing, and textiles. Currently, the industrial methods for preparing cyclohexylamine are the catalytic hydrogenation of aniline and the catalytic ammonolysis of cyclohexanol. Because the catalytic hydrogenation of aniline has low raw material costs and a simple process route, it can achieve the co-production of cyclohexylamine and dicyclohexylamine, and the yield ratio of the two products can be freely switched by adjusting the catalyst formulation and synthesis process conditions, thus attracting widespread attention from research institutions and manufacturers both domestically and internationally.

[0004] As a downstream product of aniline, cyclohexylamine is usually produced by manufacturers as two separate product units. However, if aniline and cyclohexylamine units can be combined for co-production, making full use of aniline tail gas resources and substandard aniline, turning waste into treasure, it can not only improve product efficiency but also reduce environmental pollution, resulting in significant economic and social benefits. Summary of the Invention

[0005] To achieve the above objectives, the present invention provides an apparatus for the co-production of aniline and cyclohexylamine.

[0006] The technical solution adopted in this invention is:

[0007] A co-production unit for aniline and cyclohexylamine includes an aniline tail gas treatment unit, a hydrogenation reaction unit, and a product purification unit;

[0008] The aniline tail gas treatment unit includes a cyclone separator, a metal wire mesh filter, a modified special fiber filter, a ceramic membrane filter, and a gas-liquid separator; the hydrogenation reaction unit includes a hydrogen buffer tank, an aniline feedstock tank, a hydrogen metering pump, an aniline metering pump, a hydrogen preheater, an aniline vaporization chamber, a fixed-bed reactor, a condenser, a gas-liquid separator B, a circulating hydrogen transfer pump, a crude product tank, and a crude product tank transfer pump; the product refining unit includes a primary distillation column preheater, a primary distillation column, a heat exchanger A, a primary distillation column reboiler transfer pump, a rectification column, a condenser B, a heat exchanger B, a cyclohexylamine receiving tank, a dicyclohexylamine receiving tank, a tar transfer pump, and a tar tank;

[0009] The aniline production tail gas flows sequentially through a cyclone separator, a metal wire mesh filter, a modified special fiber filter, and a ceramic membrane filter before entering a gas-liquid separator. The aniline tail hydrogen separated at the top of the gas-liquid separator enters a hydrogen buffer tank, while the aniline condensate separated at the bottom enters an aniline feed tank. The aniline tail hydrogen and fresh hydrogen in the hydrogen buffer tank are then sequentially pumped through a hydrogen metering pump and a hydrogen preheater before entering a fixed-bed reactor. The aniline condensate, along with substandard aniline and fresh aniline, enters the aniline feed tank sequentially through an aniline metering pump and an aniline vaporization chamber before entering the fixed-bed reactor. The hydrogenation product from the bed reactor enters the gas-liquid separator B via a condenser; the gas phase separated from the top of the gas-liquid separator B is returned to the inlet of the hydrogen preheater via a circulating hydrogen transfer pump; the liquid phase separated from the bottom of the gas-liquid separator B enters the crude product tank, and the liquid phase in the crude product tank sequentially enters the primary distillation column via the crude product tank transfer pump and the primary distillation column preheater; the bottom material of the primary distillation column sequentially enters the rectification column via heat exchanger A and the primary distillation column bottom transfer pump; the top material of the rectification column enters the cyclohexylamine receiving tank and the dicyclohexylamine receiving tank via condenser B, respectively, and the bottom material of the rectification column sequentially enters the tar tank via heat exchanger B and the tar transfer pump.

[0010] Furthermore, the filtration accuracy of metal wire mesh filters is 50–200 μm, the filtration accuracy of modified special fiber filters is 0.1–50 μm, and the filtration accuracy of ceramic membrane filters is 10–100 nm.

[0011] Furthermore, flow meters are installed on both the hydrogen pipeline and the aniline pipeline leading into the fixed-bed reactor.

[0012] Furthermore, the fixed-bed reactor is filled with a novel cobalt-based catalyst. The novel cobalt-based catalyst uses modified silica gel as a carrier and loads the active component Co and an auxiliary agent. The auxiliary agent is composed of two metal elements, A and B. Metal element A is La, and metal element B is at least one of Zn, Cu, Mg and Ni. The loading of Co is 1 to 40 wt%, the loading of the auxiliary agent is 0.6 to 5 wt%, and the mass percentage of La in the auxiliary agent is 4 to 50%.

[0013] Furthermore, the preparation method of the novel cobalt-based catalyst support is as follows: tetrapropylammonium hydroxide and ammonium dihydrogen phosphate are prepared into a 1.5-5% solution at a ratio of 1:(2-4); silica gel is added to the above solution and heat-treated at 120-160℃ and 0.11-0.14MPa for 4-8 hours; the mass ratio of silica gel to solution is (0.5-1):1; the heat-treated solution is vacuum dried to obtain the support.

[0014] Furthermore, the molar ratio of substandard aniline to fresh aniline is 1:(20–5), the hydrogen-to-oil ratio is (5–22):1, the hydrogenation reaction temperature is 120–200℃, the pressure is 0–0.6 MPa, and the feed space velocity is 0.05–1 h⁻¹. -1 Substandard aniline refers to aniline with excessive light components in the aniline production unit and the top discharge from the light component removal tower.

[0015] Furthermore, the theoretical number of trays in the primary distillation column is 8 to 15, and the reflux ratio of the primary distillation column is (1 to 6): 1 (the primary distillation column is an atmospheric distillation column without packing).

[0016] Furthermore, the material at the top of the primary distillation column enters the wastewater tank via condenser A.

[0017] Furthermore, the theoretical number of plates in the distillation column is 10 to 25, and the reflux ratio of the distillation is (2 to 12):1.

[0018] The beneficial effects of this invention are:

[0019] 1) The aniline and cyclohexylamine units are optimized and integrated to achieve the joint production of aniline-cyclohexylamine, with a small footprint.

[0020] 2) Making full use of aniline tail gas resources and substandard aniline products can reduce the cost of treating waste, which can not only improve product efficiency but also reduce environmental pollution, resulting in significant economic and social benefits.

[0021] 3) The equipment is simple to operate, the process conditions are mild, and the industrial application effect is good.

[0022] 4) In the catalytic hydrogenation reaction of aniline, modified silica gel is used as a support to load the active component Co, and elements such as Zn, Cu, Mg, Ni and La are added as catalyst promoters. The surface of the support has abundant basic sites, which can improve the selectivity and lifespan of the catalyst. The aniline conversion rate reaches 100% and the product selectivity is greater than 98%. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a co-production device for aniline and cyclohexylamine according to the present invention.

[0024] Explanation of reference numerals in the attached figures:

[0025] 101-Aniline production tail gas; 102-Fresh hydrogen; 103-Fresh aniline; 104-Aniline with excessive light components in the aniline production unit; 105-Top discharge from the dehydrogenation tower; 106-Catalyst particles and aniline tar; 1-Cyclone separator; 2-Metal wire mesh filter; 3-Modified special fiber filter; 4-Ceramic membrane filter; 5-Gas-liquid separator A; 6-Hydrogen buffer tank; 7-Aniline feedstock tank; 8-Hydrogen metering pump; 9-Aniline metering pump; 10-Hydrogen preheater; 11-Aniline 12-Vaporization chamber; 13-Fixed bed reactor; 14-Condenser; 15-Gas-liquid separator B; 16-Circulating hydrogen transfer pump; 17-Crude product tank; 18-Crude product tank transfer pump; 19-Primary distillation column preheater; 20-Primary distillation column; 21-Heat exchanger A; 22-Wastewater tank; 23-Primary distillation column bottom transfer pump; 24-Distillation column; 25-Condenser B; 26-Heat exchanger B; 27-Cyclohexylamine receiving tank; 28-Dicyclohexylamine receiving tank; 29-Tar transfer pump; 30-Tar tank. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and embodiments.

[0027] Example 1

[0028] See Figure 1 This embodiment provides an apparatus for the co-production of aniline and cyclohexylamine, including an aniline tail gas treatment unit, a hydrogenation reaction unit, and a product purification unit;

[0029] The aniline tail gas treatment unit includes a cyclone separator 1, a metal wire mesh filter 2, a modified special fiber filter 3, a ceramic membrane filter 4, and a gas-liquid separator 5A. The tail gas generated by the fluidized bed hydrogenation of nitrobenzene to aniline is connected to the inlet of the cyclone separator 1 through a pipeline. The outlet of the cyclone separator 1 is connected to the inlet of the metal wire mesh filter 2 through a pipeline. The outlet of the metal wire mesh filter 2 is connected to the inlet of the modified special fiber filter 3 through a pipeline. The outlet of the modified special fiber filter 3 is connected to the inlet of the ceramic membrane filter 4 through a pipeline. The outlet of the ceramic membrane filter 4 is connected to the inlet of the gas-liquid separator 5A through a pipeline.

[0030] The hydrogenation reaction unit includes a hydrogen buffer tank 6, an aniline feed tank 7, a hydrogen metering pump 8, an aniline metering pump 9, a hydrogen preheater 10, an aniline vaporization chamber 11, a fixed-bed reactor 12, a condenser 13, a gas-liquid separator B14, a circulating hydrogen transfer pump 15, a crude product tank 16, and a crude product tank transfer pump 17. The top outlet of the gas-liquid separator 5A is connected to the hydrogen buffer tank 6 through the inlet pipe of the hydrogen buffer tank. The inlet pipe of the hydrogen buffer tank is equipped with a fresh hydrogen feed pipe for introducing fresh hydrogen 102. The bottom outlet of the gas-liquid separator 5A is connected to the aniline feed tank 7 through the inlet pipe of the aniline feed tank. The inlet pipe of the aniline feed tank is equipped with a fresh aniline feed pipe for introducing fresh aniline 103, a light component excess aniline feed pipe for introducing aniline 104 (which exceeds the light component limit in the aniline production unit), and a dehydrogenation tower outlet feed pipe for introducing the top outlet 105 of the dehydrogenation tower. The outlet of the hydrogen buffer tank 6 is connected to the inlet of the hydrogen metering pump 8 via a pipeline. The outlet of the hydrogen metering pump 8 is connected to the inlet of the hydrogen preheater 10 via a pipeline. The outlet of the hydrogen preheater 10 is connected to the inlet pipeline of the fixed bed reactor 12 via a hydrogen pipeline. A hydrogen flow meter is installed on the hydrogen pipeline. The outlet of the aniline raw material tank 7 is connected to the inlet of the aniline metering pump 9 via a pipeline. The outlet of the aniline metering pump 9 is connected to the inlet of the aniline vaporization chamber 11 via a pipeline. The outlet of the aniline vaporization chamber 11 is connected to the inlet pipeline of the fixed bed reactor 12 via an aniline pipeline. An aniline flow meter is installed on the aniline pipeline. The bottom outlet of the fixed bed reactor 12 is connected to the inlet of the condenser 13 via a pipe. The outlet of the condenser 13 is connected to the inlet of the gas-liquid separator B14 via a pipe. The top outlet of the gas-liquid separator B14 is connected to the inlet of the circulating hydrogen transfer pump 15 via a pipe. The outlet of the circulating hydrogen transfer pump 15 is connected to the inlet pipe of the hydrogen preheater 10 via a pipe. The bottom outlet of the gas-liquid separator B14 is connected to the inlet of the crude product tank 16 via a pipe. The outlet of the crude product tank 16 is connected to the inlet of the crude product tank transfer pump 17 via a pipe.

[0031] The product refining unit includes a primary distillation column preheater 18, a primary distillation column 19, a condenser A20, a heat exchanger A21, a wastewater tank 22, a primary distillation column bottom transfer pump 23, a rectification column 24, a condenser B25, a heat exchanger B26, a cyclohexylamine receiving tank 27, a dicyclohexylamine receiving tank 28, a tar transfer pump 29, and a tar tank 30. The outlet of the crude product tank transfer pump 17 is connected to the inlet of the primary distillation column preheater 18 via a pipeline. The outlet of the primary distillation column preheater 18 is connected to the feed inlet of the primary distillation column 19 via a pipeline. The side outlet of the primary distillation column 19 is connected to the condenser A20 and the wastewater tank 22 via pipelines. The outlet of the condenser A20 is connected to the top inlet of the primary distillation column 19 via a pipeline. The bottom outlet of the primary distillation column 19 is connected to the heat exchanger A21 and the primary distillation column bottom transfer pump 23 via pipelines. The outlet of the heat exchanger A21 is connected to the lower inlet of the primary distillation column 19 via a pipeline. The outlet of the bottom pump 23 is connected to the feed inlet of the distillation column 24 via a pipeline. The upper outlet of the distillation column 24 is connected to the condenser B25, the cyclohexylamine receiving tank 27, and the dicyclohexylamine receiving tank 28 via pipelines. The outlet of the condenser B25 is connected to the top inlet of the distillation column 24 via a pipeline. The lower outlet of the distillation column 24 is connected to the heat exchanger B26 and the tar pump 29 via pipelines. The outlet of the heat exchanger B26 is connected to the lower inlet of the distillation column 24 via a pipeline. The outlet of the tar pump 29 is connected to the tar tank 30 via a pipeline.

[0032] The method of using this device is as follows:

[0033] 1. The tail gas generated from the fluidized bed hydrogenation of nitrobenzene to aniline enters the cyclone separator 1 through a pipeline to remove some catalyst particles and aniline tar; then it passes through the metal wire mesh filter 2 and the modified special fiber filter 3 in sequence to further remove small particles and water mist, and then through the ceramic membrane filter 4 to remove liquid organic matter and trace catalyst particles from the tail gas. After that, it enters the gas-liquid separator 5A. The aniline tail hydrogen separated from the top of the gas-liquid separator 5A is mixed with fresh hydrogen and enters the hydrogen buffer tank 6; the tail gas condensate separated from the bottom of the gas-liquid separator 5A is mixed with the substandard aniline and fresh aniline produced by the aniline unit in a certain proportion and then enters the aniline raw material tank 7.

[0034] 2. Hydrogen is introduced into the hydrogen preheater 10 through the hydrogen metering pump 8, and aniline is pumped into the aniline vaporization chamber 11 through the aniline metering pump 9. Both feed streams are equipped with flow meters to control a certain hydrogen-to-oil ratio. After the raw materials are preheated and mixed, they enter the fixed-bed reactor 12 and come into contact with the catalyst. The hydrogenation reaction is carried out under certain reaction temperature and pressure. The hydrogenation product enters the gas-liquid separator B14 after passing through the condenser 13. The gas phase returns to the reaction system through the circulating hydrogen transfer pump 15, and the liquid phase is mainly a mixture of cyclohexylamine and dicyclohexylamine, which enters the crude product tank 16.

[0035] 3. The crude product from the crude product tank outlet is pumped into the preheater A18 of the primary distillation column. The material from the primary distillation column outlet is heated to a suitable temperature by the heat exchanger A21 and then sent to the rectification column 24 by the primary distillation column bottom transfer pump 23. The side stream from the top of the rectification column 24 is cooled by the condenser B25 and collected in the cyclohexylamine receiving tank 27 and the dicyclohexylamine product receiving tank 28 according to the top vapor temperature. The material from the bottom of the rectification column is cooled by the heat exchanger B26 and then enters the tar tank 30 by the tar transfer pump 29.

[0036] Example 2

[0037] This embodiment provides a method for producing cyclohexylamine and dicyclohexylamine using the aniline and cyclohexylamine co-production apparatus described in Example 1, comprising:

[0038] (1) Preparation of catalyst support: Tetrapropylammonium hydroxide and ammonium dihydrogen phosphate were prepared into a 1.5% solution at a ratio of 1:2; silica gel was added to the above solution at a mass ratio of 0.5:1, and the solution was heat-treated at 120℃ and 0.11MPa for 8h. The heat-treated solution was then vacuum-dried at 80℃ for 4h to obtain modified silica gel.

[0039] (2) Using the above-mentioned modified silica gel as a carrier, a novel cobalt-based catalyst was prepared by loading the active component Co1wt% and the auxiliary agents Zn4.5wt% and La0.2wt%. The catalyst preparation method is existing technology and will not be described in detail here.

[0040] (3) The above-mentioned novel cobalt-based catalyst is loaded into the fixed-bed reactor 12;

[0041] (4) Cyclohexylamine and dicyclohexylamine were produced according to the method of use described in Example 1, and the production process parameters were as follows:

[0042] The aniline content in the substandard aniline is 95.5%, and the molar ratio of substandard aniline to fresh aniline is 1:15. The fixed-bed hydrogenation process is as follows: reaction temperature 120℃, pressure 0.1 MPa, and aniline feed space velocity 0.05 h⁻¹. -1 The hydrogen-to-oil ratio is 5:1.

[0043] Preliminary distillation process: distillation at atmospheric pressure at 80℃; Rectification process: vacuum of 16 mmHg, 10 theoretical plates in the rectification column, and reflux ratio of 2:1.

[0044] Cyclohexylamine and dicyclohexylamine fractions were collected and analyzed by gas chromatography (GC). The purity of cyclohexylamine was 99.8% and that of dicyclohexylamine was 99.6%. The total selectivity of cyclohexylamine and dicyclohexylamine was calculated to be 98.7%, and the total yield of cyclohexylamine and dicyclohexylamine was approximately 96% (based on aniline).

[0045] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications are also within the protection scope of the present invention.

Claims

1. A device for the co-production of aniline and cyclohexylamine, characterized in that, This includes an aniline tail gas treatment unit, a hydrogenation reaction unit, and a product refining unit; The aniline tail gas treatment unit includes a cyclone separator (1), a metal wire mesh filter (2), a modified special fiber filter (3), a ceramic membrane filter (4), and a gas-liquid separator (5); The hydrogenation reaction unit includes a hydrogen buffer tank (6), an aniline feed tank (7), a hydrogen metering pump (8), an aniline metering pump (9), a hydrogen preheater (10), an aniline vaporization chamber (11), a fixed-bed reactor (12), a condenser (13), a gas-liquid separator B (14), a circulating hydrogen transfer pump (15), a crude product tank (16), and a crude product tank transfer pump (17); The product refining unit includes a primary distillation column preheater (18), a primary distillation column (19), a heat exchanger A (21), a primary distillation column bottom transfer pump (23), a distillation column (24), a condenser B (25), a heat exchanger B (26), a cyclohexylamine receiving tank (27), a dicyclohexylamine receiving tank (28), a tar transfer pump (29), and a tar tank (30); The tail gas from aniline production flows sequentially through a cyclone separator (1), a metal wire mesh filter (2), a modified special fiber filter (3), and a ceramic membrane filter (4) before entering a gas-liquid separator (5). The aniline tail hydrogen separated at the top of the gas-liquid separator (5) enters a hydrogen buffer tank (6), and the aniline condensate separated at the bottom of the gas-liquid separator (5) enters an aniline raw material tank (7). The aniline tail hydrogen and fresh hydrogen entering the hydrogen buffer tank (6) are sequentially fed into the fixed bed reactor (12) via the hydrogen pipeline through the hydrogen metering pump (8) and the hydrogen preheater (10); Aniline condensate, substandard aniline, and fresh aniline enter the aniline raw material tank (7) and then pass through the aniline metering pump (9) and the aniline vaporization chamber (11) in sequence to enter the fixed bed reactor (12). The hydrogenation product of the fixed bed reactor (12) enters the gas-liquid separator B (14) via the condenser (13); the gas phase separated from the top of the gas-liquid separator B (14) is returned to the inlet of the hydrogen preheater (10) via the circulating hydrogen transfer pump (15); the liquid phase separated from the bottom of the gas-liquid separator B (14) enters the crude product tank (16), and the liquid phase in the crude product tank (16) enters the primary distillation column (19) via the crude product tank transfer pump (17) and the primary distillation column preheater (18). The bottom material of the primary distillation column (19) enters the rectification column (24) sequentially through heat exchanger A (21) and primary distillation column bottom transfer pump (23); the top material of the rectification column (24) enters the cyclohexylamine receiving tank (27) and dicyclohexylamine receiving tank (28) respectively through condenser B (25); the bottom material of the rectification column (24) enters the tar tank (30) sequentially through heat exchanger B (26) and tar transfer pump (29).

2. The aniline and cyclohexylamine co-production apparatus according to claim 1, characterized in that, The filtration accuracy of the metal wire mesh filter (2) is 50-200 μm, the filtration accuracy of the modified special fiber filter (3) is 0.1-50 μm, and the filtration accuracy of the ceramic membrane filter (4) is 10-100 nm.

3. The aniline and cyclohexylamine co-production apparatus according to claim 1, characterized in that, Flow meters are installed on both the hydrogen pipeline and the aniline pipeline leading into the fixed-bed reactor (12).

4. The aniline and cyclohexylamine co-production apparatus according to claim 1, characterized in that, The fixed-bed reactor (12) is filled with a novel cobalt-based catalyst. The novel cobalt-based catalyst uses modified silica gel as a carrier and loads the active component Co and an auxiliary agent. The auxiliary agent is composed of two metal elements, A and B. Metal element A is La, and metal element B is at least one of Zn, Cu, Mg and Ni. The loading of Co is 1 to 40 wt%, the loading of the auxiliary agent is 0.6 to 5 wt%, and the mass percentage of La in the auxiliary agent is 4 to 50%.

5. The aniline and cyclohexylamine co-production apparatus according to claim 4, characterized in that, The preparation method of the novel cobalt-based catalyst support is as follows: tetrapropylammonium hydroxide and ammonium dihydrogen phosphate are prepared into a 1.5-5% solution at a ratio of 1:(2-4); silica gel is added to the above solution and heat-treated at 120-160℃ and 0.11-0.14MPa for 4-8 hours; the mass ratio of silica gel to solution is (0.5-1):1; the heat-treated solution is vacuum dried to obtain the support.

6. The aniline and cyclohexylamine co-production apparatus according to claim 3, characterized in that, The molar ratio of substandard aniline to fresh aniline is 1:(20–5), the hydrogen-to-oil ratio is (5–22):1, the hydrogenation reaction temperature is 120–200℃, the pressure is 0–0.6 MPa, and the feed space velocity is 0.05–1 h⁻¹. -1 Substandard aniline refers to aniline with excessive light components in the aniline production unit and the top discharge from the light component removal tower.

7. The aniline and cyclohexylamine co-production apparatus according to claim 1, characterized in that, The theoretical number of trays in the primary distillation column is 8 to 15, and the reflux ratio of the primary distillation column is (1 to 6):

1.

8. The aniline and cyclohexylamine co-production apparatus according to claim 1, characterized in that, The material at the top of the primary distillation column (19) enters the wastewater tank (22) via condenser A (20).

9. The aniline and cyclohexylamine co-production apparatus according to claim 1, characterized in that, The theoretical number of plates in the distillation column is 10 to 25, and the reflux ratio of the distillation is (2 to 12):1.

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