Efficient separation and circulation storage tank device for caprolactam ammonium sulfate production

Abstract

The utility model discloses an efficient separation circulating storage tank device for caprolactam-grade ammonium sulfate production, which relates to the technical field of caprolactam-grade ammonium sulfate production and comprises a mother liquor separation tank, a stirring mechanism is arranged in the mother liquor separation tank, and a dissolution separation mechanism is arranged at the bottom of the mother liquor separation tank. The stirring mechanism can improve the dissolving efficiency, the dissolving and separating mechanism effectively dissolves crystals during normal operation, the degree of supersaturation of the ammonium sulfate mother liquor of the system is reduced, the temperature of the mother liquor is increased, and the dissolution and separation efficiency of the ammonium sulfate mother liquor is improved. The blocking of the mother liquor circulating extraction pipe caused by excessive crystals at the bottom of the tank is avoided, the risks of stirring stop and equipment damage caused by excessive crystal accumulation possibly caused by long-term operation are also avoided, and the recovery efficiency and the recovery amount of crude caprolactam oil on the upper layer of the ammonium sulfate mother liquor in the tank can be improved by the blocking mechanism.

Description

Technical Field

[0001] This utility model relates to the field of caprolactam-grade ammonium sulfate production technology, specifically a high-efficiency separation and circulation storage tank device for caprolactam-grade ammonium sulfate production. Background Technology

[0002] The caprolactam industry is a product of many high-tech fields in the chemical industry, and its production process is complex and lengthy. In the ammoximation process for producing caprolactam, cyclohexanone, hydrogen peroxide, and gaseous ammonia are reacted in tert-butanol solvent with titanium silicate molecular sieve as a catalyst to carry out the ammoximation reaction of cyclohexanone. The resulting cyclohexanone oxime is purified and then reacted with nicotinic acid containing 20% ​​(wt) SO3 in a Beckmann rearrangement reaction to obtain crude caprolactam oil. In a neutralization crystallization reactor, high-quality liquid ammonia is used to neutralize sulfuric acid in crude oil to produce ammonium sulfate mother liquor. The amide oil and mother liquor suspended in the settling zone of the crystallizer are pumped away and sent to a decanter for separation. The light phase containing amide oil overflows through a baffle into the light phase zone of the decanter and then flows by gravity to the crude caprolactam storage tank. Meanwhile, the ammonium sulfate slurry and mother liquor in the crystallizer are pumped to a thickener to process the crystals. The ammonium sulfate mother liquor containing some crude caprolactam oil, including the mother liquor in the heavy phase zone of the decanter, is sent to a mother liquor tank for further oil phase separation.

[0003] Currently, all caprolactam plants use a baffle plate in their ammonium sulfate mother liquor tanks to separate crude caprolactam oil. By controlling the overflow height of the mother liquor tank above the baffle plate, the oil phase on the upper layer of the mother liquor overflows through the baffle plate to the lighter phase zone, and then is pumped to a decanter for further settling and separation. This method achieves the separation of amide oil from the ammonium sulfate circulating mother liquor. The mother liquor tank is equipped with a stirring device, and the large inflow and outflow rates, coupled with the fact that the ammonium sulfate mother liquor is a supersaturated solution, and the distance between the stirring end and the bottom of the tank, easily leads to the accumulation of ammonium sulfate crystals at the bottom of the mother liquor tank. Over long operating cycles, the large accumulation of crystals can cause blockage of the bottom mother liquor extraction outlet. Simultaneously, the large inflow and outflow rates make it difficult to control the stability of the tank level. This results in a large amount of supersaturated ammonium sulfate mother liquor being carried into the lighter phase zone when the crude caprolactam oil on the upper layer overflows through the baffle plate, leading to low separation efficiency.

[0004] Based on this, a high-efficiency separation and circulation storage tank device for the production of caprolactam-grade ammonium sulfate is provided, which can eliminate the drawbacks of existing devices. Utility Model Content

[0005] The purpose of this invention is to provide a high-efficiency separation and circulation storage tank device for the production of caprolactam-grade ammonium sulfate, so as to solve the problems in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] A high-efficiency separation and circulation storage tank device for the production of caprolactam-grade ammonium sulfate includes a mother liquor separation tank, a stirring mechanism is provided inside the mother liquor separation tank, a dissolution separation mechanism is provided at the bottom of the mother liquor separation tank, and a barrier mechanism is provided on one side of the dissolution separation mechanism inside the mother liquor separation tank.

[0008] Based on the above technical solutions, this utility model also provides the following optional technical solutions:

[0009] In one alternative: the stirring mechanism includes a motor located at the top of the mother liquor separation tank, and the motor output end is provided with a stirring shaft, on which stirring blades are provided.

[0010] In one alternative: a process water inlet pipe and a steam inlet pipe are respectively provided on one side of the bottom of the mother liquor separator.

[0011] In one alternative: the dissolution and separation mechanism includes a heating and dissolution coil located at the bottom of the mother liquor separation tank.

[0012] In one alternative: the barrier mechanism includes a primary separation baffle located at the bottom of the mother liquor separation tank on one side of the heating and dissolving coil, and a secondary separation baffle and a tertiary separation baffle are respectively provided on one side of the primary separation baffle.

[0013] In one alternative: a mother liquor recovery self-circulation pump is installed on the outside of the mother liquor separation tank. One end of the mother liquor recovery self-circulation pump is connected to the bottom of the mother liquor separation tank through an inlet pipe, and the other end of the mother liquor recovery self-circulation pump is connected to the top of the mother liquor separation tank through a mother liquor recovery return pipe.

[0014] In one alternative: a separation oil phase discharge pump is provided on one side of the mother liquor recovery self-circulation pump, and one end of the separation oil phase discharge pump is connected to one side of the bottom of the mother liquor separation tank through a connecting pipe.

[0015] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0016] 1. This utility model adds process water and steam pipelines and a heating and dissolving coil to the bottom of the existing ammonium sulfate mother liquor tank. During normal operation, it effectively dissolves crystals, reduces the supersaturation of the ammonium sulfate mother liquor in the system, and increases the temperature of the mother liquor. This avoids blockage of the mother liquor circulation pipe caused by excessive crystals at the bottom of the tank, and also avoids the risk of excessive crystal accumulation causing agitation and equipment damage during long-term operation. The existing ammonium sulfate mother liquor is heated by an external heater in the storage tank. The heating and dissolving coil is installed inside the pipe, which heats the mother liquor while dissolving the crystals at the bottom of the tank. Compared with the existing solution, this reduces the number of process steps and process equipment, and the effect is far superior to the current solution.

[0017] 2. This utility model improves the recovery efficiency and amount of crude caprolactam oil in the upper layer of the ammonium sulfate mother liquor by setting up a three-stage separation baffle in the existing ammonium sulfate mother liquor tank, and by adding a mother liquor recovery self-circulation pump and reflux pipeline at the bottom of the separation baffle. Through the multi-stage static separation of the baffle and the reflux effect of the bottom mother liquor circulation pump, the treatment effect is far superior to the current solution. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0019] Figure 2 This is a schematic diagram of the overall internal structure of this utility model.

[0020] Figure label annotations: 1. Heating and dissolving coil; 2. Process water inlet pipe; 3. Steam inlet pipe; 4. Primary separation baffle; 5. Secondary separation baffle; 6. Tertiary separation baffle; 7. Mother liquor recovery self-circulation pump; 8. Inlet pipe; 9. Mother liquor recovery reflux pipe; 10. Separation oil phase side discharge pump; 11. Connecting pipe; 12. Mother liquor separation tank; 13. Motor; 14. Stirring shaft; 15. Stirring blade. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments.

[0022] In one embodiment, such as Figures 1-2 As shown, a high-efficiency separation and circulation storage tank device for the production of caprolactam-grade ammonium sulfate includes a mother liquor separation tank 12. The mother liquor separation tank 12 is equipped with a stirring mechanism and a dissolution separation mechanism at its bottom. A barrier mechanism is located on one side of the dissolution separation mechanism within the mother liquor separation tank 12. The stirring mechanism improves dissolution efficiency. During normal operation, the dissolution separation mechanism effectively dissolves crystals, reducing the supersaturation of the ammonium sulfate mother liquor in the system and simultaneously increasing the mother liquor temperature. This prevents blockage of the mother liquor circulation extraction pipe due to excessive crystals at the bottom of the tank and avoids the risk of excessive crystal accumulation during long-term operation, which could cause stirring to stop and damage the equipment. The barrier mechanism improves the recovery efficiency and amount of crude caprolactam oil in the upper layer of the ammonium sulfate mother liquor in the tank.

[0023] In one embodiment, such as Figure 2 As shown, the stirring mechanism includes a motor 13, which is located at the top of the mother liquor separation tank 12. A stirring shaft 14 is provided at the output end of the motor 13, and stirring blades 15 are provided on the stirring shaft 14. Starting the motor 13 can drive the stirring blades 15 on the stirring shaft 14 to rotate, thereby improving the solution dissolution efficiency.

[0024] In one embodiment, such as Figure 2As shown, the bottom side of the mother liquor separator 12 is equipped with a process water inlet pipe 2 and a steam inlet pipe 3, respectively. By adding process water and steam, the crystals can be effectively dissolved, reducing the supersaturation of the ammonium sulfate mother liquor in the system.

[0025] In one embodiment, such as Figure 2 As shown, the dissolution and separation mechanism includes a heating and dissolution coil 1, which is located at the bottom of the mother liquor separation tank 12. This increases the temperature of the mother liquor, avoids blockage of the mother liquor circulation extraction pipe due to excessive crystals at the bottom of the tank, and also avoids the risk of excessive crystal accumulation during long-term operation, which could cause the agitator to stop and damage the equipment.

[0026] In one embodiment, such as Figure 2 As shown, the barrier mechanism includes a primary separation baffle 4, which is located on one side of the heating and dissolving coil 1 at the bottom of the mother liquor separation tank 12. A secondary separation baffle 5 and a tertiary separation baffle 6 are respectively installed on one side of the primary separation baffle 4. Through the multi-stage static separation of the baffles and the reflux effect of the bottom mother liquor circulation pump, the recovery efficiency and recovery amount of crude caprolactam oil in the upper layer of ammonium sulfate mother liquor in the tank are improved.

[0027] In one embodiment, such as Figure 2 As shown, a mother liquor recovery self-circulation pump 7 is installed on the outside of the mother liquor separation tank 12. One end of the mother liquor recovery self-circulation pump 7 is connected to the bottom of the mother liquor separation tank 12 through the inlet pipe 8, and the other end of the mother liquor recovery self-circulation pump 7 is connected to the top of the mother liquor separation tank 12 through the mother liquor recovery return pipe 9. This can improve the recovery efficiency and recovery amount of crude caprolactam oil, and eliminate the risks of ammonium sulfate crystal accumulation, pipeline blockage, and equipment stalling in the existing scheme.

[0028] In one embodiment, such as Figure 2 As shown, a separation oil phase discharge pump 10 is installed on one side of the mother liquor recovery self-circulation pump 7. One end of the separation oil phase discharge pump 10 is connected to one side of the bottom of the mother liquor separation tank 12 through a connecting pipe 11 for discharging.

[0029] The above embodiments disclose a high-efficiency separation and circulation storage tank device for the production of caprolactam-grade ammonium sulfate. During use, ammonium sulfate has high solubility in water, and its solubility increases with increasing temperature. The ammonium sulfate crystals at the bottom of the mother liquor tank are dissolved using process water and steam. Taking advantage of the different solubilities of ammonium sulfate and crude caprolactam oil in water, a three-stage separation baffle is set in the mother liquor tank to recover the crude caprolactam oil on the upper layer of the ammonium sulfate mother liquor to the oil phase storage tank, thereby improving the recovery amount and efficiency of crude caprolactam oil. The process water flow rate is controlled at approximately 4 t / h, the steam flow rate at approximately 1 t / h, and the dissolution temperature at approximately 55°C.

[0030] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A high-efficiency separation and circulation storage tank device for the production of caprolactam-grade ammonium sulfate, comprising a mother liquor separation tank (12), characterized in that, The mother liquor separation tank (12) is equipped with a stirring mechanism, a dissolution separation mechanism is provided at the bottom of the mother liquor separation tank (12), and a barrier mechanism is provided on one side of the dissolution separation mechanism inside the mother liquor separation tank (12).

2. The high-efficiency separation and circulating storage tank device for the production of caprolactam-grade ammonium sulfate according to claim 1, characterized in that, The stirring mechanism includes a motor (13), which is located at the top of the mother liquor separation tank (12). The output end of the motor (13) is provided with a stirring shaft (14), and the stirring shaft (14) is provided with stirring blades (15).

3. The high-efficiency separation and circulating storage tank device for the production of caprolactam-grade ammonium sulfate according to claim 1, characterized in that, The bottom side of the mother liquor separator (12) is provided with a process water inlet pipe (2) and a steam inlet pipe (3).

4. The high-efficiency separation and circulating storage tank device for the production of caprolactam-grade ammonium sulfate according to claim 1, characterized in that, The dissolution and separation mechanism includes a heating and dissolution coil (1), which is located at the bottom of the mother liquor separation tank (12).

5. The high-efficiency separation and circulating storage tank device for the production of caprolactam-grade ammonium sulfate according to claim 1, characterized in that, The barrier mechanism includes a primary separation baffle (4), which is located at the bottom of the mother liquor separation tank (12) on one side of the heating and dissolving coil (1). A secondary separation baffle (5) and a tertiary separation baffle (6) are respectively provided on one side of the primary separation baffle (4).

6. The high-efficiency separation and circulating storage tank device for the production of caprolactam-grade ammonium sulfate according to claim 1, characterized in that, A mother liquor recovery self-circulation pump (7) is provided on the outside of the mother liquor separation tank (12). One end of the mother liquor recovery self-circulation pump (7) is connected to the bottom of the mother liquor separation tank (12) through an inlet pipe (8), and the other end of the mother liquor recovery self-circulation pump (7) is connected to the top of the mother liquor separation tank (12) through a mother liquor recovery return pipe (9).

7. The high-efficiency separation and circulating storage tank device for the production of caprolactam-grade ammonium sulfate according to claim 6, characterized in that, The mother liquor recovery self-circulation pump (7) is provided with an oil phase separation side discharge pump (10) on one side. One end of the oil phase separation side discharge pump (10) is connected to the bottom side of the mother liquor separation tank (12) through a connecting pipe (11).

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