A production system and method for co-producing large-particle-size purified adipic acid and high-quality nylon 66 salt

Abstract

The present invention belongs to the field of production equipment and process technology of chemical products, and specifically relates to a production system for co-producing large-particle-size refined adipic acid and high-quality nylon 66 salt. It includes a refined adipic acid centrifuge, a refined adipic acid fluidized bed, a large-particle-size refined adipic acid conveying system, a small-particle-size refined adipic acid conveying system, a cyclone dust collector, a dust adsorption tower, a high-quality nylon 66 salt reactor, and a high-quality nylon 66 salt storage tank; the refined adipic acid particle size screening is completed by the fluidized bed's own air volume, and the large-particle-size refined adipic acid has good circulation performance, and the packaging and sales improve the quality of the product; the small-particle-size refined adipic acid and the recovered dust are used in the production of nylon 66 salt, which improves the utilization rate of the product.

Description

Technical Field

[0001] The invention belongs to the field of production equipment and process technology of chemical products, and specifically relates to a production system and a production method for co-producing large-particle-size refined adipic acid and high-quality nylon 66 salt. Background Art

[0002] Adipic acid is the most important aliphatic dibasic acid and can undergo condensation reaction with multifunctional compounds, such as hexamethylenediamine. In industry, nylon 66 salt (abbreviated as AH salt) is produced by condensation reaction of adipic acid and hexamethylenediamine, and nylon 66 resin can be obtained by further polycondensation reaction of nylon 66 salt. In addition, adipic acid can also react with alcohols to produce adipic acid esters, which are used as plasticizers, synthetic lubricants, polyester polyols and other products.

[0003] In view of the problem of adipic acid particles agglomerating during the packaging and sale of adipic acid in the current production process, a production process for the co-production of large-particle adipic acid and high-quality nylon 66 salt was designed. The problem of adipic acid packaging agglomeration was solved through screening of adipic acid particles, thereby improving product quality and increasing product utilization. Summary of the invention

[0004] The object of the present invention is to provide a production system and a production method for co-producing large-particle adipic acid and high-quality nylon 66 salt. The particle size screening of refined adipic acid is completed by the air volume of the fluidized bed itself. The large-particle refined adipic acid has good circulation performance, and the packaging and sale improves the quality of the product; the small-particle refined adipic acid and the recovered dust are used in the production of nylon 66 salt, thereby improving the utilization rate of the product.

[0005] Based on the above purpose, the present invention adopts the following technical solution:

[0006] A production system for co-producing large-particle refined adipic acid and high-quality nylon 66 salt, comprising a refined adipic acid centrifuge, a refined adipic acid fluidized bed, a large-particle refined adipic acid conveying system, a small-particle refined adipic acid conveying system, a cyclone dust collector, a dust adsorption tower, a high-quality nylon 66 salt reactor, and a high-quality nylon 66 salt storage tank.

[0007] Preferably, the purified adipic acid fluidized bed is connected to the outlet of the purified adipic acid centrifuge, with a disperser disposed in the middle.

[0008] Preferably, the fluidized bed inlet is provided with a guide plate, and the vertical angle is set at 15-30 degrees.

[0009] Preferably, a wind chamber is provided at the lower part of the fluidized bed, and the inlet of the wind chamber is connected to a fan.

[0010] Preferably, the first outlet of the fluidized bed is located in the lower middle part of the fluidized bed, and a gate valve is provided at the outlet.

[0011] Preferably, the first outlet is provided with a star-shaped discharge valve, a long screw conveyor and a bucket elevator.

[0012] Preferably, the second outlet of the fluidized bed is located in the upper middle part of the fluidized bed, and a gate valve is provided at the outlet. The second outlet is provided with a star-shaped discharge valve, a long screw conveyor and a bucket elevator. The upper outlet of the fluidized bed is connected to the inlet of the cyclone dust collector, and the upper outlet of the cyclone dust collector is connected to the inlet of the dust washing tower. The washing tower is provided with two-stage circulation absorption.

[0013] Preferably, the first inlet of the high-quality nylon 66 salt reactor is connected to the upper feed long spiral outlet, and the upper long spiral is provided with a frequency conversion motor; the second inlet of the high-quality nylon 66 salt reactor is provided with a refined hexamethylenediamine pipeline, the third inlet is connected to the washing tower outlet, and the reactor is provided with a circulating pump and a cooler.

[0014] A method for co-producing large-particle-size refined adipic acid and high-quality nylon 66 salt comprises the following steps:

[0015] (1) The air volume of the air chamber is 8000-12000m3 / h, the temperature is 145-155°C, the fluidized bed is provided with a heater, the temperature is 115-125°C, and the air enters the fluidized bed from the bottom of the fluidized bed and runs in a cross-flow with the purified adipic acid falling from the top;

[0016] (2) Under the action of air volume, the purified adipic acid particles with a particle size larger than 0.3 mm are located in the suspended layer at the bottom of the fluidized bed, and are controlled by the gate valve to flow out through the first outlet, pass through the star-shaped discharge valve, the long screw conveyor, and the bucket elevator, and then are sent to the packaging machine through the long screw conveyor.

[0017] A method for co-producing large-particle-size refined adipic acid and high-quality nylon 66 salt comprises the following steps:

[0018] (1) The air volume of the air chamber is 8000-12000m3 / h, the temperature is 145-155°C, the fluidized bed is provided with a heater, the temperature is 115-125°C, and the air enters the fluidized bed from the bottom of the fluidized bed and runs in a cross-flow with the purified adipic acid falling from the top;

[0019] (2) Under the action of air volume, the refined adipic acid particles with a particle size of less than 0.3 mm are located in the upper suspension layer of the fluidized bed, and are controlled by the gate valve to flow out through the second outlet, and are sent to the high-quality nylon 66 salt reactor feed long spiral, and then enter the reactor;

[0020] The ratio of the purified adipic acid output from the first outlet and the second outlet of the fluidized bed is 1:2-1:3.

[0021] Advantages of the present invention:

[0022] 1. Through the design of the present invention, by taking advantage of the fluidized bed itself, the internal space is large, and adipic acid particles of different sizes enter from the upper part of the fluidized bed with different falling speeds, and the speed difference with the rising speed of the hot air entering from the bottom forms an adipic acid particle suspension layer, thereby completing the screening of refined adipic acid particles. Refined adipic acid particles with large particle sizes are packaged for sale, and have good circulation performance and are not agglomerated.

[0023] 2. The small-size refined adipic acid particles from the fluidized bed are mixed with the refined adipic acid particles from the cyclone dust collector and used for the nylon 66 salt reaction, while the solution from the dust absorption tower is used as the solvent for the nylon 66 salt reaction. In this way, the utilization rate of adipic acid is greatly improved and no waste liquid is generated. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0025] The present invention is further described below in conjunction with embodiments and drawings, but is not intended to limit the present invention.

[0026] In the description of the present invention, it should be noted that directional words, such as the terms "altitude", "left", "right", "horizontal", "vertical", etc., which indicate directions and positional relationships are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and cannot be understood as limiting the specific protection scope of the present invention.

[0027] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so as to describe the embodiments of the present application described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions.

[0028] Example 1

[0029] like Figure 1 A production system for co-producing large-particle-size refined adipic acid and high-quality nylon 66 salt, comprising a refined adipic acid centrifuge, a refined adipic acid fluidized bed 2, a large-particle-size refined adipic acid conveying system 300, a small-particle-size refined adipic acid conveying system 400, a cyclone dust collector 3, a dust adsorption tower 7, a high-quality nylon 66 salt reactor 5, and a high-quality nylon 66 salt storage tank 6;

[0030] The refined adipic acid fluidized bed 2 is connected to the refined adipic acid centrifuge parameter outlet. In order to prevent large crystal particles from entering the fluidized bed, a scatterer 101 is provided in the middle. A guide plate 201 is provided at the inlet of the fluidized bed. The vertical angle is between 15-30 to buffer the falling speed of the refined adipic acid and ensure that the refined adipic acid is in a fluidized state after entering the fluidized bed.

[0031] A wind chamber is provided at the bottom of the fluidized bed. The inlet of the wind chamber is connected to the outlet of the fan 202. The air volume is controlled at 8000m 3 / h, the air volume and temperature are at 145℃, and the air enters the fluidized bed from the bottom of the fluidized bed, and runs in a cross-flow with the refined adipic acid falling from the top. When the settling speed of the refined adipic acid corresponds to the rising speed of the air volume, the adipic acid particles are in a suspended state. Because the adipic acid particles have a certain deviation in particle size, the adipic acid particles form a suspended layer from bottom to top and from large to small in the fluidized bed. The temperature is controlled at 115℃ by the internal heater set in the fluidized bed, and the refined adipic acid is further dried;

[0032] The first outlet of the fluidized bed is located in the lower middle part of the fluidized bed. Under the action of air volume, the refined adipic acid particles with a particle size larger than 0.3 mm are located in the suspended layer at the lower part of the fluidized bed, and are controlled by the gate valve 300 to flow out through the first outlet. The first outlet is provided with a star-shaped discharge valve 301, a long screw conveyor 302, and a bucket elevator 303. The large-size refined adipic acid particles are sent to the packaging machine 305 through the long screw conveyor 304 for sale. The packaged adipic acid has a large particle size and a small specific surface area. The ash content (≤1.6 mg / kg) and nitrate content (≤0.1 mg / kg) in the product are greatly reduced, exceeding the national control indicators, and the product has good fluidity and no moisture and caking phenomenon occurs.

[0033] The second outlet of the fluidized bed is located in the middle and upper part of the fluidized bed. Under the action of the air volume, the refined adipic acid particles with a particle size of less than 0.3 mm are located in the upper suspension layer of the fluidized bed and are controlled by the gate valve 400 to flow out through the second outlet. The second outlet is provided with a star-shaped discharge valve 401, a long screw conveyor 402, and a bucket elevator 403, which feed the refined adipic acid particles with small particle size into the high-quality nylon 66 salt reactor feed long screw 404, and then enter the reactor 5;

[0034] The ratio of the discharge amount of purified adipic acid from the first outlet and the second outlet of the fluidized bed is controlled at 1:2.

[0035] The upper outlet of the fluidized bed is connected to the inlet of the cyclone dust collector 3. Some adipic acid particles with a particle size of less than 0.05 mm enter the cyclone dust collector 3 with the air volume. Under the action of centrifugal force, more than 90% of the refined adipic acid particles enter the lower part of the dust collector 3, and are sent to the high-quality nylon 66 salt reactor feed long spiral 404 through the star-shaped discharge valve, and then enter the high-quality nylon 66 salt reactor;

[0036] The upper outlet of the cyclone dust collector 3 is connected to the inlet of the dust washing tower 7. The washing tower 7 is provided with two-stage circulation absorption. The absorption liquid is high-purity water. After the absorption is completed, the dust amount carried by the air volume is less than 10 mg / m3. The absorption liquid is used as the diluent of the high-quality nylon 66 salt reactor 5. The adipic acid concentration is 0.8wt% and the water content is greater than 99wt%.

[0037] The first inlet of the high-quality nylon 66 salt reactor 5 is connected to the outlet of the upper feed long spiral 404. The upper long spiral is provided with a variable frequency motor to adjust the feed amount of refined adipic acid. The opening of the gate valve 400 is controlled by the DCS to adjust the reaction amount of the high-quality nylon 66 salt.

[0038] The second inlet of the high-quality nylon 66 salt reactor 5 is provided with a refined hexamethylenediamine pipeline with a concentration of 70wt%. The third inlet is connected to the outlet of the washing tower 7. The three groups of materials, refined adipic acid with a concentration of about 70wt%, and the absorption liquid of the absorption tower are stirred in the high-quality nylon 66 salt reactor 5. After sufficient reaction, they overflow into the high-quality nylon 66 salt storage tank 6. The reactor is provided with a circulation pump 501 and a cooler 502 to remove the reaction heat and detect the concentration and pH value of the high-quality nylon 66 salt, with a concentration of about 45wt% and a pH value of 7. At the same time, the high-quality nylon 66 salt reaction is kept stable at about 50-60°C.

[0039] In this system, the fluidized bed completes the drying and screening of adipic acid particles. The quality and flowability of large-particle adipic acid products after screening are improved. The remaining small-particle adipic acid is used in the production of nylon 66 salt, which solves the problem of dust removal in the drying system. The dust content in the tail gas is greatly reduced (10mg / m3), which is better than the national standard. The waste liquid is absorbed and used in the production of nylon 66 salt, reducing the amount of wastewater, thereby increasing the recovery rate of dry adipic acid by more than 98wt%.

[0040] Example 2

[0041] like Figure 1 , a production system for co-producing large-particle-size refined adipic acid and high-quality nylon 66 salt, comprising a refined adipic acid centrifuge, a refined adipic acid fluidized bed 2, a large-particle-size refined adipic acid conveying system 300, a small-particle-size refined adipic acid conveying system 400, a cyclone dust collector 3, a dust adsorption tower 7, a high-quality nylon 66 salt reactor 5, and a high-quality nylon 66 salt storage tank 6;

[0042] The refined adipic acid fluidized bed 2 is connected to the refined adipic acid centrifuge parameter outlet. In order to prevent large crystal particles from entering the fluidized bed, a scatterer 101 is provided in the middle. A guide plate 201 is provided at the inlet of the fluidized bed with a vertical angle of 15 degrees to buffer the falling speed of the refined adipic acid and ensure that the refined adipic acid is in a fluidized state after entering the fluidized bed.

[0043] A wind chamber is provided at the lower part of the fluidized bed, the inlet of which is connected to the outlet of the fan 202, the air volume is controlled at about 10000m3 / h, the air temperature is about 155°C, and the air enters the fluidized bed from the bottom of the fluidized bed, and runs in a cross-flow with the refined adipic acid falling from the top. When the settling speed of the refined adipic acid corresponds to the rising speed of the air volume, the adipic acid particles are in a suspended state. Since the adipic acid particles have a certain deviation in particle size, the adipic acid particles form a suspended layer from bottom to top and from large to small particle sizes in the fluidized bed, and the internal heater (temperature controlled at about 120°C) provided in the fluidized bed further completes the drying of the refined adipic acid;

[0044] The first outlet of the fluidized bed is located in the lower middle part of the fluidized bed. Under the action of air volume, the refined adipic acid particles with a particle size larger than 0.3 mm are located in the suspended layer at the lower part of the fluidized bed, and are controlled by the gate valve 300 to flow out through the first outlet. The first outlet is provided with a star-shaped discharge valve 301, a long screw conveyor 302, and a bucket elevator 303. The large-size refined adipic acid particles are sent to the packaging machine 305 through the long screw conveyor 304 for sale. The packaged adipic acid has a large particle size and a small specific surface area. The ash content (≤1.6 mg / kg) and nitrate content (≤0.1 mg / kg) in the product are greatly reduced, exceeding the national control indicators, and the product has good fluidity and no moisture and caking phenomenon occurs.

[0045] The second outlet of the fluidized bed is located in the middle and upper part of the fluidized bed. Under the action of the air volume, the refined adipic acid particles with a particle size of less than 0.3 mm are located in the upper suspension layer of the fluidized bed and are controlled by the gate valve 400 to flow out through the second outlet. The second outlet is provided with a star-shaped discharge valve 401, a long screw conveyor 402, and a bucket elevator 403, which feed the refined adipic acid particles with small particle size into the high-quality nylon 66 salt reactor feed long screw 404, and then enter the reactor 5;

[0046] The ratio of the discharge amount of purified adipic acid from the first outlet and the second outlet of the fluidized bed is controlled at 1:3.

[0047] The upper outlet of the fluidized bed is connected to the inlet of the cyclone dust collector 3. Some adipic acid particles with a particle size of less than 0.05 mm enter the cyclone dust collector 3 with the air volume. Under the action of centrifugal force, more than 90% of the refined adipic acid particles enter the lower part of the dust collector 3, and are sent to the high-quality nylon 66 salt reactor feed long spiral 404 through the star-shaped discharge valve, and then enter the high-quality nylon 66 salt reactor;

[0048] The upper outlet of the cyclone dust collector 3 is connected to the inlet of the dust washing tower 7. The washing tower 7 is provided with two-stage circulation absorption. The absorption liquid is high-purity water. After the absorption is completed, the dust amount carried by the air volume is less than 10 mg / m3. The absorption liquid is used as a diluent of the high-quality nylon 66 salt reactor 5, with a concentration of adipic acid of 1wt% and a water content of 99wt%);

[0049] The first inlet of the high-quality nylon 66 salt reactor 5 is connected to the outlet of the upper feed long spiral 404. The upper long spiral is provided with a variable frequency motor to adjust the feed amount of refined adipic acid. The opening of the gate valve 400 is controlled by the DCS to adjust the reaction amount of the high-quality nylon 66 salt.

[0050] A refined hexamethylenediamine pipeline is arranged at the second inlet of the high-quality nylon 66 salt reactor 5, and the concentration is about 80wt%. The third inlet is connected to the outlet of the washing tower 7. Three groups of materials, refined adipic acid, with a concentration of about 65-90wt%, and the absorption liquid of the absorption tower are stirred in the high-quality nylon 66 salt reactor 5. After sufficient reaction, they overflow into the high-quality nylon 66 salt storage tank 6. The reactor is provided with a circulation pump 501 and a cooler 502 to remove the reaction heat, and detect the concentration and pH value of the high-quality nylon 66 salt, with a concentration of about 55wt% and a pH value of 8.5. At the same time, the high-quality nylon 66 salt reaction is kept stable at about 60°C.

[0051] In this system, the fluidized bed completes the drying and screening of adipic acid particles. The quality and flowability of large-particle adipic acid products after screening are improved. The remaining small-particle adipic acid is used in the production of nylon 66 salt, which solves the problem of dust removal in the drying system. The dust content in the tail gas is greatly reduced (6mg / m3), which is better than the national standard. The waste liquid is absorbed and used in the production of nylon 66 salt, reducing the amount of wastewater, thereby increasing the recovery rate of dry adipic acid by more than 98wt%.

Claims

1. A production system for co-producing large-particle-size refined adipic acid and high-quality nylon 66 salt, characterized by: It includes a refined adipic acid centrifuge, a refined adipic acid fluidized bed, a large-particle refined adipic acid conveying system, a small-particle refined adipic acid conveying system, a cyclone dust collector, a dust adsorption tower, a high-quality nylon 66 salt reactor, and a high-quality nylon 66 salt storage tank; the first outlet of the fluidized bed is located in the middle and lower part of the fluidized bed, and the outlet is provided with a gate valve; the first outlet is provided with a star-shaped discharge valve, a long screw conveyor and a bucket elevator; the second outlet of the fluidized bed is located in the middle and upper part of the fluidized bed, and the outlet is provided with a gate valve, the second outlet is provided with a star-shaped discharge valve, a long screw conveyor and a bucket elevator, the upper outlet of the fluidized bed is connected to the inlet of the cyclone dust collector, the upper outlet of the cyclone dust collector is connected to the inlet of the dust washing tower, and the washing tower is provided with two-stage circulation absorption; the first inlet of the high-quality nylon 66 salt reactor is connected to the upper inlet The first outlet is equipped with a star-shaped discharge valve, a long screw conveyor and a bucket elevator, and the large-size refined adipic acid particles are sent to the packaging machine through the long screw conveyor; the refined adipic acid particles with a particle size of less than 0.3 mm are located in the upper suspension layer of the fluidized bed, and are controlled by the gate valve to flow out through the second outlet. The second outlet is equipped with a star-shaped discharge valve, a long screw conveyor and a bucket elevator, and the small-size refined adipic acid particles are sent to the high-quality nylon 66 salt reactor feeding long spiral, and then enter the reactor.

2. A production system for co-producing large-particle-size purified adipic acid and high-quality nylon 66 salt as claimed in claim 1, characterized in that: The purified adipic acid fluidized bed is connected to the outlet of the purified adipic acid centrifuge, and a disperser is arranged in the middle.

3. The production system for co-producing large-particle-size purified adipic acid and high-quality nylon 66 salt according to claim 1, characterized in that: The fluidized bed inlet is provided with a guide plate, and the vertical angle is set at 15-30 degrees.

4. The production system for co-producing large-particle-size purified adipic acid and high-quality nylon 66 salt according to claim 1, characterized in that: A wind chamber is arranged at the lower part of the fluidized bed, and the inlet of the wind chamber is connected with a fan.

5. A production method using a production system for co-producing large-particle-size purified adipic acid and high-quality nylon 66 salt as described in any one of claims 1 to 4, characterized in that: The steps include: (1) The air volume of the air chamber is 8000-12000m 3 / h, the temperature is 145-155℃, entering the fluidized bed from the bottom of the fluidized bed, and running in a cross-flow with the purified adipic acid falling from the top; (2) Under the action of air volume, the purified adipic acid particles with a particle size greater than 0.3 mm are located in the suspended layer at the bottom of the fluidized bed, and are controlled by the gate valve to flow out through the first outlet, passing through the star-shaped discharge valve, the long screw conveyor, and the bucket elevator.

6. A production method using a production system for co-producing large-particle-size purified adipic acid and high-quality nylon 66 salt as described in any one of claims 1 to 4, characterized in that: The steps include: (1) The air volume of the air chamber is 8000-12000m 3 / h, the temperature is 145-155℃, entering the fluidized bed from the bottom of the fluidized bed, and running in a cross-flow with the purified adipic acid falling from the top; (2) Under the action of air volume, the purified adipic acid particles with a particle size of less than 0.3 mm are located in the upper suspension layer of the fluidized bed, and are controlled by the gate valve to flow out through the second outlet, and are sent to the high-quality nylon 66 salt reactor feed long spiral, and then enter the reactor; the first outlet and the second outlet of the fluidized bed The purified adipic acid output ratio is set to 1:2-1:3.

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