A device for reducing the content of lactam in ammonium sulphate finished product

Abstract

This invention discloses a device for reducing the caprolactam content in finished ammonium sulfate products, comprising an amide oil storage tank, a condenser at the top of the tank, and a crystallizer fixedly connected to the bottom of the tank. The top of the crystallizer is connected to the bottom of the tank, and a first transfer pump is installed on one side of the crystallizer. A thickener is installed on the side wall of the first transfer pump. By adding a rinsing device inside the centrifuge, caprolactam adhering to the surface of ammonium sulfate crystals is effectively recovered. Based on the average operating data of the device over one month, the average caprolactam content in the recovered ammonium sulfate solution is 0.0863%wt, with an annual caprolactam recovery of approximately 777 tons. Based on market prices, the annual economic benefit is approximately 6.83 million yuan. The recovery of caprolactam significantly reduces resource waste, thereby lowering production costs and improving the economic benefits of enterprises. It also reduces the content of harmful substances in waste, which is beneficial to environmental protection and sustainable development.

Description

Technical Field

[0001] This invention relates to the field of chemical technology, specifically to a device for reducing the lactam content in finished ammonium sulfate products. Background Technology

[0002] In existing caprolactam production processes, the neutralization process is a crucial step. In this process, the rearranged liquid and gaseous ammonia are separately added to the neutralization crystallizer through nozzles. Simultaneously, a suitable amount of water is added to the crystallizer, and the heat generated by the neutralization reaction evaporates the added water. The neutralization product, ammonium sulfate, forms a slurry in the crystallizer, which is then thickened, centrifuged, and dried to finally obtain the finished ammonium sulfate product. However, this process presents a significant problem: the finished ammonium sulfate product contains approximately 0.1595% wt% caprolactam, resulting in a loss of about 1435 tons of caprolactam annually. This not only causes significant resource waste but also significantly increases production costs. Summary of the Invention

[0003] The purpose of this invention is to provide a device for reducing the lactam content in finished ammonium sulfate products, so as to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a device for reducing the lactam content in ammonium sulfate finished product, comprising an amide oil storage tank, a condenser provided at the top of the amide oil storage tank, a crystallizer fixedly connected to the bottom of the amide oil storage tank, the top of the crystallizer being connected through to the bottom of the amide oil storage tank, a first delivery pump provided on one side of the crystallizer, a thickener provided on the side wall of one side of the first delivery pump, a second delivery pump provided on the side wall of one side of the thickener, a centrifuge provided on one side of the second delivery pump, a gas assembly provided at the top of the centrifuge, a centrifugal motor fixedly connected to the side wall of one side of the centrifuge, the output end of the centrifugal motor being fixedly connected to the working end of the centrifuge, and an ammonium sulfate dryer provided on the side wall of one side of the centrifuge.

[0005] As a further aspect of the present invention: a gaseous ammonia input pipe is fixedly connected through one side wall of the crystallizer.

[0006] As a further embodiment of the present invention: the working end of the condenser is fixedly connected to a top tube, and the end of the top tube away from the condenser is fixedly connected through the top of the amide oil storage tank.

[0007] As a further embodiment of the present invention: the working end of the first delivery pump is fixedly connected to a first delivery pipe, and the first delivery pipe is fixedly connected through the crystallizer and the thickener respectively.

[0008] As a further embodiment of the present invention: the working end of the second delivery pump is fixedly connected to a second delivery pipe, and the second delivery pipe is fixedly connected through the thickener and the centrifuge respectively.

[0009] As a further embodiment of the present invention: the gas assembly includes a third delivery pump, the working end of which is fixedly connected to a third delivery pipe, and the third delivery pipe is fixedly connected through the top of the centrifuge.

[0010] As a further embodiment of the present invention: a regulating valve is provided on the side wall of the third conveying pipe near the centrifuge end, and a flow meter is provided on the end of the third conveying pipe near the regulating valve.

[0011] As a further embodiment of the present invention: a connecting pipe is fixedly connected through the side wall of the ammonium sulfate dryer near the centrifuge, and the side of the connecting pipe away from the ammonium sulfate dryer is fixedly connected to the discharge port of the centrifuge.

[0012] As a further embodiment of the present invention: a steam pipe is fixedly connected through one side wall of the ammonium sulfate dryer, a condensate pipe is fixedly connected through the side wall of the ammonium sulfate dryer at the bottom of the steam pipe, a hot air pipe is fixedly connected through one side wall of the ammonium sulfate dryer, and a cold air pipe is fixedly connected through the side wall of the ammonium sulfate dryer near the hot air pipe.

[0013] As a further embodiment of the present invention: a circulating water inlet pipe is fixedly connected through the side wall of the ammonium sulfate dryer near the cold air pipe, an ammonium sulfate outlet pipe is fixedly connected through the side wall of the ammonium sulfate dryer, a circulating water outlet pipe is fixedly connected through the side wall of the ammonium sulfate dryer near the ammonium sulfate outlet pipe, and a drying exhaust gas outlet pipe is fixedly connected through the side wall of the ammonium sulfate dryer on the side of the circulating water outlet pipe.

[0014] Compared with existing technologies, the beneficial effects of this invention are: by adding a rinsing device inside the centrifuge, caprolactam adhering to the surface of ammonium sulfate crystals is effectively recovered. Based on the average operating data of the device over one month, the average caprolactam content in the recovered ammonium sulfate solution is 0.0863%wt, with an annual caprolactam recovery of approximately 777 tons. Calculated at market prices, the annual economic benefit is approximately 6.83 million yuan.

[0015] Reduced production costs: The recovery of caprolactam significantly reduces resource waste, thereby lowering production costs and improving the economic benefits of enterprises.

[0016] Environmental benefits: It reduces the content of harmful substances in waste, which is conducive to environmental protection and sustainable development. Attached Figure Description

[0017] Figure 1This is a schematic diagram of the main structure of a device for reducing the lactam content in ammonium sulfate finished product according to the present invention; Figure 2 This is a schematic diagram of the gas component in a device for reducing the lactam content in ammonium sulfate product according to the present invention; Figure 3 This is an enlarged schematic diagram of the structure of the ammonium sulfate dryer in the device for reducing the lactam content in the finished ammonium sulfate product according to the present invention; Figure 4 This is an experimental curve diagram of an apparatus for reducing the lactam content in ammonium sulfate product according to the present invention.

[0018] In the diagram: 1. Amide oil storage tank; 2. Crystallizer; 3. Ammonia gas input pipe; 4. Condenser; 41. Top pipe; 5. First transfer pump; 51. First transfer pipe; 6. Thickener; 7. Second transfer pump; 71. Second transfer pipe; 8. Centrifuge; 9. Gas assembly; 91. Third transfer pump; 92. Third transfer pipe; 93. Regulating valve; 94. Flow meter; 10. Centrifugal motor; 11. Ammonium sulfate dryer; 12. Connecting pipe; 13. Steam pipe; 14. Condensate pipe; 15. Hot air pipe; 16. Cold air pipe; 17. Circulating water inlet pipe; 18. Ammonium sulfate outlet pipe; 19. Circulating water outlet pipe; 20. Drying exhaust gas discharge pipe. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0021] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0022] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "configuration" should be interpreted broadly. For example, they can refer to a fixed connection or configuration, a detachable connection or configuration, or an integral connection or configuration. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0023] Please see Figures 1-3 In this embodiment of the invention, a device for reducing the lactam content in ammonium sulfate finished product includes an amide oil storage tank 1. A condenser 4 is provided on the top of the amide oil storage tank 1, and a crystallizer 2 is fixedly connected to the bottom of the amide oil storage tank 1. The top of the crystallizer 2 is connected through to the bottom of the amide oil storage tank 1. A first delivery pump 5 is provided on one side of the crystallizer 2. A thickener 6 is provided on the side wall of one side of the first delivery pump 5. A second delivery pump 7 is provided on the side wall of one side of the thickener 6. A centrifuge 8 is provided on one side of the second delivery pump 7. A gas assembly 9 is provided on the top of the centrifuge 8. A centrifugal motor 10 is fixedly connected to the side wall of one side of the centrifuge 8. The output end of the centrifugal motor 10 is fixedly connected to the working end of the centrifuge 8. An ammonium sulfate dryer 11 is provided on the side wall of one side of the centrifuge 8.

[0024] A gaseous ammonia input pipe 3 is fixedly connected through one side wall of the crystallizer 2.

[0025] The working end of the condenser 4 is fixedly connected to a top pipe 41, and the end of the top pipe 41 away from the condenser 4 is fixedly connected through the top of the amide oil storage tank 1.

[0026] The working end of the first delivery pump 5 is fixedly connected to the first delivery pipe 51, which is fixedly connected to the crystallizer 2 and the thickener 6 respectively.

[0027] The working end of the second delivery pump 7 is fixedly connected to the second delivery pipe 71, which is fixedly connected to the thickener 6 and the centrifuge 8 respectively.

[0028] The gas assembly 9 includes a third delivery pump 91, with a third delivery pipe 92 fixedly connected to the working end of the third delivery pump 91. The third delivery pipe 92 is fixedly connected to the top of the centrifuge 8. A regulating valve 93 is provided on the side wall of the third delivery pipe 92 near the centrifuge 8, and a flow meter 94 is provided on the end of the third delivery pipe 92 near the regulating valve 93.

[0029] A connecting pipe 12 is fixedly connected through the side wall of the ammonium sulfate dryer 11 near the centrifuge 8. The side of the connecting pipe 12 away from the ammonium sulfate dryer 11 is fixedly connected to the discharge port of the centrifuge 8.

[0030] A steam pipe 13 is fixedly connected to one side wall of the ammonium sulfate dryer 11. A condensate pipe 14 is fixedly connected to the side wall of the ammonium sulfate dryer 11 located at the bottom of the steam pipe 13. A hot air pipe 15 is fixedly connected to one side wall of the ammonium sulfate dryer 11. A cold air pipe 16 is fixedly connected to the side wall of the ammonium sulfate dryer 11 located near the hot air pipe 15. A circulating water inlet pipe 17 is fixedly connected to the side wall of the ammonium sulfate dryer 11 located near the cold air pipe 16. An ammonium sulfate outlet pipe 18 is fixedly connected to one side wall of the ammonium sulfate dryer 11. A circulating water outlet pipe 19 is fixedly connected to the side wall of the ammonium sulfate dryer 11 located near the ammonium sulfate outlet pipe 18. A drying exhaust gas outlet pipe 20 is fixedly connected to the side wall of the ammonium sulfate dryer 11 located near the circulating water outlet pipe 19.

[0031] The third delivery pipe 92 passes through one end of the centrifuge 8 and is connected to a spray head.

[0032] Please see Figure 4 During the experiment, 100g of wet ammonium sulfate solid produced by the device (centrifuge output) was weighed. During the filtration process, the wet ammonium sulfate solid was washed with demineralized water at a certain ratio. The filtered solid was dried and weighed. Finally, the content of hexane in the solid and filtrate was determined.

[0033] The working principle of this invention is as follows: by adding a rinsing device inside the centrifuge 8, the caprolactam adhering to the surface of the ammonium sulfate crystals is eluted using a rinsing solution (such as demineralized water). The eluted caprolactam is recovered and reused along with the rinsing solution, thereby reducing the caprolactam content in the finished ammonium sulfate product.

[0034] Usage steps: Preparation phase: Check that all components of the equipment are intact and ensure that the rinsing device, transfer pump, gas assembly 9, etc. are working properly.

[0035] Start-up phase: Start the crystallizer 2, thickener 6, centrifuge 8, and other equipment to begin the neutralization reaction and solid-liquid separation process. At the same time, prepare the eluent and connect it to the eluent device.

[0036] Washing stage: When centrifuge 8 begins to separate ammonium sulfate crystals, the washing device is started to wash the crystals.

[0037] By adjusting the regulating valve 93 and the flow meter 94 in the gas assembly 9, the gas flow rate and the amount of rinsing liquid used in the rinsing process can be precisely controlled.

[0038] Collection and recycling stage: Collect the rinsed ammonium sulfate crystals and the recycled hexane, dry the crystals to obtain the finished ammonium sulfate; further process the recycled hexane to extract caprolactam and reuse it.

[0039] Shutdown and maintenance phase: After production is completed, all equipment is shut down and cleaning and maintenance are carried out to ensure that the unit can operate normally when it is restarted next.

[0040] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0041] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A device for reducing the lactam content in finished ammonium sulfate product, comprising an amide oil storage tank (1), characterized in that: A condenser (4) is provided on the top of the amide oil storage tank (1), and a crystallizer (2) is fixedly connected to the bottom of the amide oil storage tank (1). The top of the crystallizer (2) is connected through to the bottom of the amide oil storage tank (1). A first delivery pump (5) is provided on one side of the crystallizer (2). A thickener (6) is provided on the side wall of one side of the first delivery pump (5). A second delivery pump (7) is provided on the side wall of one side of the thickener (6). A centrifuge (8) is provided on one side of the second delivery pump (7). A gas assembly (9) is provided on the top of the centrifuge (8). A centrifugal motor (10) is fixedly connected to the side wall of one side of the centrifuge (8). The output end of the centrifugal motor (10) is fixedly connected to the working end of the centrifuge (8). An ammonium sulfate dryer (11) is provided on the side wall of one side of the centrifuge (8).

2. The device for reducing the lactam content in ammonium sulfate product according to claim 1, characterized in that: A gaseous ammonia input pipe (3) is fixedly connected through one side wall of the crystallizer (2).

3. The device for reducing the lactam content in ammonium sulfate product according to claim 1, characterized in that: The working end of the condenser (4) is fixedly connected to a top tube (41), and the end of the top tube (41) away from the condenser (4) is fixedly connected through the top of the amide oil storage tank (1).

4. The device for reducing the lactam content in ammonium sulfate product according to claim 1, characterized in that: The working end of the first delivery pump (5) is fixedly connected to the first delivery pipe (51), and the first delivery pipe (51) is fixedly connected to the crystallizer (2) and the thickener (6) respectively.

5. The device for reducing the lactam content in ammonium sulfate product according to claim 1, characterized in that: The working end of the second delivery pump (7) is fixedly connected to the second delivery pipe (71), which is fixedly connected to the thickener (6) and the centrifuge (8) respectively.

6. The device for reducing the lactam content in ammonium sulfate product according to claim 1, characterized in that: The gas assembly (9) includes a third delivery pump (91), the working end of which is fixedly connected to a third delivery pipe (92), which is fixedly connected to the top of the centrifuge (8).

7. The device for reducing the lactam content in ammonium sulfate product according to claim 6, characterized in that: A regulating valve (93) is provided on the side wall of the third conveying pipe (92) near the centrifuge (8), and a flow meter (94) is provided on the end of the third conveying pipe (92) near the regulating valve (93).

8. The device for reducing the lactam content in ammonium sulfate product according to claim 1, characterized in that: A connecting pipe (12) is fixedly connected through the side wall of the ammonium sulfate dryer (11) near the centrifuge (8), and the side of the connecting pipe (12) away from the ammonium sulfate dryer (11) is fixedly connected to the outlet of the centrifuge (8).

9. The device for reducing the lactam content in ammonium sulfate product according to claim 1, characterized in that: A steam pipe (13) is fixedly connected to one side wall of the ammonium sulfate dryer (11). A condensate pipe (14) is fixedly connected to the side wall of the ammonium sulfate dryer (11) at the bottom of the steam pipe (13). A hot air pipe (15) is fixedly connected to one side wall of the ammonium sulfate dryer (11). A cold air pipe (16) is fixedly connected to the side wall of the ammonium sulfate dryer (11) near the hot air pipe (15).

10. The device for reducing the lactam content in ammonium sulfate product according to claim 9, characterized in that: A circulating water inlet pipe (17) is fixedly connected through the side wall of the ammonium sulfate dryer (11) near the cold air pipe (16). An ammonium sulfate outlet pipe (18) is fixedly connected through the side wall of the ammonium sulfate dryer (11) near the ammonium sulfate outlet pipe (18). A circulating water outlet pipe (19) is fixedly connected through the side wall of the ammonium sulfate dryer (11) on the side of the circulating water outlet pipe (19). A drying exhaust gas outlet pipe (20) is fixedly connected through the side wall of the ammonium sulfate dryer (11) on the side of the circulating water outlet pipe (19).

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