A method for separating cyclohexanone waste water

Abstract

The present application belongs to the technical field of solvent extraction, and particularly relates to a method for separating cyclohexanone wastewater. The separation method comprises the following steps: taking n-propyl acetate as an extractant, feeding the cyclohexanone wastewater into an extraction tower for extraction, and obtaining an extraction phase rich in cyclohexanone and the extractant; the extraction phase enters an extractant recovery tower for rectification and separation, the recovered n-propyl acetate is obtained at the top of the tower, and cyclohexanone is obtained at the bottom of the tower. By selecting n-propyl acetate as the extractant, the present application can effectively break the azeotropy of cyclohexanone and water, realize efficient separation, and the recovery rate of cyclohexanone can reach more than 99.18%, and the purity is more than 99.99%. The process flow of the present application is simple, the operation conditions are mild, and the extractant can be recycled, so that the present application has good economic efficiency and environmental protection. The present application can be used for treating wastewater and recycling and purifying cyclohexanone in the production process of cyclohexanone.

Description

Technical Field

[0001] This invention belongs to the field of solvent extraction technology, specifically relating to a method for separating cyclohexanone wastewater. Background Technology

[0002] Cyclohexanone is an important organic solvent widely used in the chemical, pharmaceutical, and automotive industries. Industrially, cyclohexanone is typically produced using the liquid-phase oxidation of cyclohexane, which generates wastewater containing cyclohexanone. In this wastewater, when the water content is 61.6 wt% and the cyclohexanone content is 38.4 wt%, cyclohexanone and water form an azeotrope with an azeotropic temperature of 95°C. The presence of this azeotrope makes it difficult to effectively separate cyclohexanone from water using conventional distillation methods, posing challenges to cyclohexanone recovery and wastewater treatment.

[0003] To address the challenge of separating cyclohexanone-water azeotropes, existing technologies typically employ specialized distillation methods such as salt distillation, extractive distillation, azeotropic distillation, and pressure swing distillation. Salt distillation involves adding salts like calcium chloride or potassium acetate to the system to alter the relative volatility of the components, thereby breaking the azeotrope. However, this method suffers from difficulties in salt recovery, equipment clogging, and strong corrosiveness. Extractive distillation uses high-boiling-point solvents as extractants to increase the relative volatility of cyclohexanone. However, these extractants usually have high boiling points, resulting in significant energy consumption during extractant recovery, and some extractants are toxic and environmentally unfriendly. Pressure swing distillation utilizes the characteristic of azeotropic composition changing with pressure to achieve separation. This process typically requires multiple distillation columns operating at different pressures, leading to high equipment investment, operational complexity, and high energy consumption.

[0004] In summary, existing methods for separating cyclohexanone-water azeotropes generally suffer from technical drawbacks such as insufficient separation efficiency and purity, high energy consumption and costs, and complex processes. Summary of the Invention

[0005] In order to overcome the shortcomings of low efficiency, high energy consumption and complex process in the separation of cyclohexanone-water azeotropic system in the prior art, the present invention provides a method for separating cyclohexanone wastewater in an efficient and economical manner.

[0006] This invention employs a two-stage process of "liquid-liquid extraction and distillation separation" in an extraction tower and an extractant recovery tower. During the liquid-liquid extraction process in the extraction tower, the high selectivity of n-propyl acetate is utilized to transfer the majority of cyclohexanone in the cyclohexanone wastewater to the extract phase under mild conditions in a single step, reducing the organic matter concentration in the raffinate to 1 ppm, fundamentally solving the problem of direct wastewater discharge meeting standards. Secondly, since dehydration is already completed in the liquid-liquid extraction process, the extract phase sent to the extractant recovery tower for distillation separation has a simple composition, containing only cyclohexanone, n-propyl acetate, and trace amounts of water. This allows subsequent extractant recovery and cyclohexanone purification to be completed using conventional distillation; completely avoiding the use of complex extractive distillation, salt distillation, or expensive pressure swing distillation, achieving low-energy consumption, low-investment, easy-to-operate, high-safety, and high-purity cyclohexanone separation.

[0007] To achieve the aforementioned technical objectives, the technical solution adopted by this invention is as follows: This invention provides a method for separating cyclohexanone wastewater. The method is based on an extraction separation system, which includes an extraction tower and an extractant recovery tower. The top outlet of the extraction tower is connected to the extractant recovery tower, allowing the extractant phase from the extraction tower to enter the extractant recovery tower. The top outlet of the extractant recovery tower is connected to the bottom of the extraction tower, allowing the extractant separated in the extractant recovery tower to recycle back into the extraction tower. The method for separating cyclohexanone wastewater includes the following steps: Using n-propyl acetate as the extractant, cyclohexanone wastewater is fed into an extraction tower for extraction to separate the raffinate phase and the extract phase rich in cyclohexanone and extractant. The extract phase rich in cyclohexanone and extractant is then fed into an extractant recovery tower. By adjusting the feed flow rate of the cyclohexanone wastewater to 400 kg / h to 500 kg / h and the number of trays in the extraction tower to 3 to 5, the feed flow rate of the extract phase rich in cyclohexanone and extractant entering the extractant recovery tower is 500 kg / h to 600 kg / h. Based on the feed flow rate of the extract phase entering the extractant recovery tower of 500 kg / h to 600 kg / h, the reflux ratio of the extractant recovery tower is adjusted to 0.5 to 1.5, and the extract phase rich in cyclohexanone and extractant is subjected to distillation separation to separate n-propyl acetate and cyclohexanone.

[0008] Preferably, the mass ratio of cyclohexanone wastewater to extractant is 1:1 to 1.5. When the extractant dosage is too low, incomplete extraction of cyclohexanone is likely, resulting in a large amount of cyclohexanone remaining in the raffinate and reducing the recovery rate. While excessive extractant dosage can further improve the extraction rate, it significantly increases the processing load on the extractant recovery tower, leading to increased energy consumption and equipment size. Furthermore, excessive extractant allows more trace amounts of water to enter the subsequent distillation unit, increasing the difficulty of separation.

[0009] Preferably, the extraction column has 3 to 5 trays and operates at a temperature of 25°C to 35°C. Too few trays result in insufficient mass transfer of cyclohexanone and a low extraction rate; too many trays increase equipment investment and reduce economic efficiency. 3 to 5 trays balance separation efficiency and engineering costs. Too low an operating temperature increases system viscosity, hindering mass transfer and phase separation; while too high an operating temperature accelerates mass transfer, the solubility of n-propyl acetate in water increases with temperature, while the partition coefficient and selectivity decrease. A temperature of 25°C to 35°C ensures good flowability and rapid phase separation while maintaining high extraction selectivity, achieving mild and efficient pre-separation. This simplifies conditions for subsequent distillation and effectively overcomes the shortcomings of existing processes, such as high energy consumption, complex operation, and easy equipment corrosion.

[0010] Preferably, the extractant recovery tower has 15-20 trays, a top temperature of 80-100℃, and a bottom temperature of 160-165℃. Insufficient trays result in inadequate separation and substandard product purity; excessive trays increase equipment investment and energy consumption. Too low a top temperature makes it difficult to extract qualified cyclohexanone, while too high a temperature easily carries away heavy components, affecting purity. The bottom temperature must ensure complete vaporization and recovery of the extractant to avoid residue; a too low reflux ratio results in insufficient separation, while a too high ratio increases energy consumption. These separation parameters achieve efficient and stable separation with low energy consumption, resulting in a simple process, high safety, and superior economy.

[0011] Preferably, the feed flow rate of the extractant in the extraction tower is 500 kg / h to 600 kg / h.

[0012] Preferably, the mass concentration of cyclohexanone in the cyclohexanone wastewater is 33wt% to 50wt%.

[0013] Preferably, the purity of the cyclohexanone obtained after separation is greater than 99.99%, and the recovery rate of cyclohexanone is greater than 99.18%.

[0014] Compared with the prior art, the present invention has the following technical effects: This invention achieves a coupled process of "liquid-liquid extraction-distillation separation" by constructing an extraction separation system consisting of an extraction tower and an extractant recovery tower connected in series. This invention utilizes the excellent selective extraction capability of n-propyl acetate for cyclohexanone wastewater, efficiently transferring organic matter from the wastewater to the extract phase, reducing the organic matter concentration in the raffinate water to below 1 ppm, and achieving a water purity of over 98%. Simultaneously, by adjusting the feed flow rate of the cyclohexanone wastewater to 400 kg / h–500 kg / h and the number of trays in the extraction tower to 3–5, the extract phase, rich in cyclohexanone and extractant, enters the extractant recovery tower at a feed flow rate of 500 kg / h–600 kg / h; and by controlling the reflux ratio to 0.5–1.5, efficient separation of cyclohexanone and extractant can be achieved under mild operating conditions. This separation method completely eliminates the complex equipment required for extractive distillation, salt distillation, or pressure swing distillation in existing technologies, resulting in a simple process, mild operating conditions, and significantly reduced equipment investment and energy consumption. Moreover, the present invention can achieve a recovery rate of over 99.18% for cyclohexanone in cyclohexanone wastewater, with a purity exceeding 99.99%, thus realizing the recovery of high-purity cyclohexanone and the treatment of wastewater.

[0015] The extractant n-propyl acetate used in this invention can be recycled through an extractant recovery tower, reducing production costs and waste emissions, making it an environmentally friendly separation process. Furthermore, the separation process of this invention is carried out under normal pressure and extraction temperatures of 25℃~35℃ and distillation temperatures of 80℃~100℃, far below the boiling point of cyclohexanone and the recovery temperatures of other high-boiling-point solvents. This not only avoids the risks of polymerization and decomposition of materials caused by high temperatures but also reduces the safety hazards of system leakage, flammability, and explosion, significantly improving the safety controllability and long-term operational stability of the production process. Attached Figure Description

[0016] Figure 1 This is a process flow diagram of the extraction and separation process of the cyclohexanone-water system of the present invention.

[0017] Figure labels: 1-Extraction tower; 2-Extractant recovery tower; 3-Raw material feed line; 4-Extractant feed line; 5-Extractant phase discharge line; 6-Raffinate phase discharge line; 7-Extractant circulation line; 8-Cyclohexanone discharge line; 9-Mixer; 10-Mixed extractant feed line. Detailed Implementation

[0018] The core of the method for separating cyclohexanone wastewater provided by this invention lies in the selection of the extractant. An ideal extractant should meet the following conditions: its solubility for cyclohexanone is much greater than its solubility for water, i.e., it has high selectivity and partition coefficient; its boiling point is significantly different from that of cyclohexanone, facilitating low-cost separation of the two through subsequent distillation; and it is chemically stable, non-toxic or low-toxic, and has low corrosiveness to ensure process safety and environmental protection.

[0019] After extensive screening, this invention discovered that n-propyl acetate is an excellent extractant for cyclohexanone-water systems. Its mechanism of action lies in the strong intermolecular interaction between the ester groups in the n-propyl acetate molecule and the cyclohexanone molecule, resulting in excellent affinity for cyclohexanone. Simultaneously, its hydrophobic propyl chain makes it extremely miscible with water. This dual characteristic of being both cyclohexanone-loving and hydrophobic allows n-propyl acetate to selectively extract cyclohexanone from the aqueous phase into its own phase when in contact with cyclohexanone wastewater, effectively disrupting the original azeotropic equilibrium.

[0020] Compared to commonly used high-boiling-point organic solvents in existing technologies, n-propyl acetate has a boiling point of 101.6℃, slightly higher than cyclohexanone (155.6℃) and water, but much lower than high-boiling-point extractants. Therefore, in the extractant recovery tower, n-propyl acetate requires only a small amount of energy to vaporize and separate from cyclohexanone, significantly reducing energy consumption in the extractant regeneration process. Furthermore, it avoids the polymerization or decomposition problems that may occur when high-boiling-point extractants are heated for extended periods at the bottom of the tower, ensuring long-term stable operation of the system.

[0021] This invention employs a two-stage process of "liquid-liquid extraction and distillation separation" in an extraction tower and an extractant recovery tower. During the liquid-liquid extraction process in the extraction tower, the high selectivity of n-propyl acetate is utilized to transfer the majority of cyclohexanone in the cyclohexanone wastewater to the extract phase under mild conditions in a single step, reducing the organic matter concentration in the raffinate to 1 ppm, fundamentally solving the problem of direct wastewater discharge meeting standards. Secondly, since dehydration is already completed in the liquid-liquid extraction process, the extract phase sent to the extractant recovery tower for distillation separation has a simple composition, containing only cyclohexanone, n-propyl acetate, and trace amounts of water. This allows subsequent extractant recovery and cyclohexanone purification to be completed using conventional distillation towers, completely avoiding the use of complex extractive distillation, salt distillation, or expensive pressure swing distillation. This achieves low-energy consumption, low-investment, easy-to-operate, high-safety, and high-purity cyclohexanone separation.

[0022] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments and accompanying drawings.

[0023] Unless otherwise specified, all reagents used in this invention are commercially available, and all methods used are conventional techniques in the art.

[0024] like Figure 1As shown, the extraction and separation system of the present invention mainly includes an extraction tower 1 and an extractant recovery tower 2. The specific connection relationship is as follows: the raw material feed line 3 is connected to the extraction tower 1; the fresh extractant feed line 4 and the extractant circulation line 7 are respectively connected to the inlet of the mixer 9, and the outlet of the mixer 9 is connected to the extraction tower 1 through the mixed extractant feed line 10; the top of the extraction tower 1 is connected to the extractant recovery tower 2 through the extract phase discharge line 5; the bottom of the extraction tower 1 is connected to the raffinate discharge line 6; the top of the extractant recovery tower 2 is connected to the extractant circulation line 7, which is used to send the recovered extractant back to the mixer 9; the bottom of the extractant recovery tower 2 is connected to the cyclohexanone discharge line 8.

[0025] The extraction and separation process is as follows: Cyclohexanone wastewater enters extraction tower 1 through feed line 3; the extractant includes fresh extractant and recovered extractant. The fresh extractant and the recovered extractant returned via extractant circulation line 7 are mixed in mixer 9 and then enter extraction tower 1 through mixed extractant feed line 10. Extraction takes place in extraction tower 1. The extract phase, rich in cyclohexanone and extractant, enters extractant recovery tower 2 from the top of extraction tower 1 via extractant discharge line 5, thus achieving the extraction of extractant and cyclohexanone. The water-rich raffinate phase is discharged from the bottom of extraction tower 1 via raffinate discharge line 6. In extractant recovery tower 2, through distillation separation, the lighter components of the extractant are circulated back to mixer 9 from the top of extractant recovery tower 2 via extractant circulation line 7 and then returned to extraction tower 1 for use. The heavier components of cyclohexanone are collected from the bottom of extractant recovery tower 2 via cyclohexanone discharge line 8, yielding high-purity cyclohexanone product.

[0026] Example 1 A method for separating cyclohexanone wastewater includes the following steps: Using n-propyl acetate as the extractant, cyclohexanone wastewater was fed into extraction tower 1 at a feed rate of 400 kg / h through feed line 3; the mass concentration of cyclohexanone in the wastewater was 38.4 wt%. n-propyl acetate was fed into extraction tower 1 at a feed rate of 500 kg / h through mixed extractant feed line 10. The internal pressure of extraction tower 1 was 1 atm, the number of trays was 5, and the operating temperature was 30℃. The mass ratio of cyclohexanone wastewater to n-propyl acetate was 1:1.25.

[0027] After extraction and separation in extraction tower 1, an extract phase rich in cyclohexanone and extractant, and a raffinate phase rich in water are obtained. In the extract phase rich in cyclohexanone and extractant, the mass fractions of n-propyl acetate, cyclohexanone, and water are 64.6%, 32.5%, and 2.9%, respectively. The raffinate phase rich in water is discharged from the bottom of extraction tower 1 via raffinate discharge line 6, with a flow rate of 315.6 kg / h. The cyclohexanone content is less than 1 ppm, and the water content is 98.4%.

[0028] The extract phase, rich in cyclohexanone and extractant, is fed from the top of extraction column 1 through extract phase discharge line 5 at a flow rate of 584.4 kg / h into extractant recovery column 2. The feed location is the 10th tray from top to bottom in extractant recovery column 2, and the reflux ratio is 1. The internal pressure of extractant recovery column 2 is set to 1 atm, the number of trays is 20, the top temperature is 95.8℃, and the bottom temperature is 164.2℃. In extractant recovery column 2, n-propyl acetate, as a light component, is collected from the top of extractant recovery column 2 through extractant circulation line 7 and recycled back to extraction column 1. The top collection flow rate is 396 kg / h, and the mass fraction of n-propyl acetate in the top product is 98.3%. Cyclohexanone, as a heavy component, is collected from the bottom of extractant recovery column 2 through cyclohexanone discharge line 8. The bottom collection flow rate is 188.4 kg / h, and the mass fraction of cyclohexanone in the bottom product is greater than 99.99%. The recovery rate of cyclohexanone was over 99.18%.

[0029] Example 2 A method for separating cyclohexanone wastewater includes the following steps: Using n-propyl acetate as the extractant, cyclohexanone wastewater was fed into extraction tower 1 at a feed flow rate of 500 kg / h through feed line 3; the mass concentration of cyclohexanone in the wastewater was 50 wt%. n-propyl acetate was also fed into extraction tower 1 at a feed flow rate of 500 kg / h through extractant feed line 4. Extraction tower 1 had an internal pressure of 1 atm, 6 trays, and an operating temperature of 25℃. The mass ratio of cyclohexanone wastewater to extractant was 1:1. After extraction and separation in extraction tower 1, an extract phase rich in cyclohexanone and extractant and a raffinate phase rich in water were obtained. In the extract phase rich in cyclohexanone and extractant, the mass fractions of n-propyl acetate, cyclohexanone, and water were 63.6%, 33.4%, and 2.8%, respectively. The raffinate phase rich in water was discharged from the bottom of extraction tower 1 through raffinate discharge line 6 at a flow rate of 253.1 kg / h. The cyclohexanone content is less than 1 ppm, and the water content is 98.0%.

[0030] The extract phase, rich in cyclohexanone and extractant, is fed from the top of extraction column 1 through extract phase discharge line 5 into extractant recovery column 2 at a flow rate of 746.9 kg / h. The feed location is the 7th tray from top to bottom in extractant recovery column 2, with a reflux ratio of 1.2. Extractant recovery column 2 is set with an internal pressure of 1 atm, 15 trays, a top temperature of 95.0℃, and a bottom temperature of 164.5℃. Inside extractant recovery column 2, n-propyl acetate, as a light component, is collected from the top of extractant recovery column 2 through extractant circulation line 7 and recycled back to extraction column 1. The top product flow rate is 496.6 kg / h, and the mass fraction of n-propyl acetate in the top product is 95.6%. Cyclohexanone, as a heavy component, is collected from the bottom of the extractant recovery tower 2 via the cyclohexanone discharge pipeline 8. The bottom collection flow rate is 250.3 kg / h, the mass fraction of cyclohexanone in the bottom collection is greater than 99.9%, and the recovery rate of cyclohexanone is above 99.99%.

[0031] Example 3 A method for separating cyclohexanone wastewater includes the following steps: Using n-propyl acetate as the extractant, cyclohexanone wastewater was fed into extraction tower 1 at a feed rate of 400 kg / h through feed line 3; the mass concentration of cyclohexanone in the wastewater was 33.3 wt%. n-propyl acetate was fed into extraction tower 1 at a feed rate of 600 kg / h through extractant feed line 4. Extraction tower 1 had an internal pressure of 1 atm, 6 trays, and an operating temperature of 35℃. The mass ratio of cyclohexanone wastewater to extractant was 1:1.5. After extraction and separation in extraction tower 1, an extract phase rich in cyclohexanone and extractant and a raffinate phase rich in water were obtained. In the extract phase rich in cyclohexanone and extractant, the mass fractions of n-propyl acetate, cyclohexanone, and water were 80.6%, 17.0%, and 2.4%, respectively. The water-rich raffinate is discharged from the bottom of extraction tower 1 through raffinate discharge pipeline 6, with a flow rate of 293.1 kg / h; the cyclohexanone content is less than 1 ppm and the water content is 98.0%.

[0032] The extract phase, rich in cyclohexanone and extractant, is fed from the top of extraction column 1 through extract phase discharge line 5 into extractant recovery column 2 at a flow rate of 706.9 kg / h. The feed position is the 8th tray from top to bottom in extractant recovery column 2, and the reflux ratio is 1.1. The internal pressure of extractant recovery column 2 is set at 1 atm, the number of trays is 19, the top temperature is 97.9℃, and the bottom temperature is 164.2℃. Inside extractant recovery column 2, n-propyl acetate, as a light component, is collected from the top of extractant recovery column 2 through extractant circulation line 7 and recycled back to extraction column 1. The top product flow rate is 590 kg / h, and the mass fraction of n-propyl acetate in the top product is 96.5%. Cyclohexanone, as a heavy component, is collected from the bottom of the extractant recovery tower 2 via the cyclohexanone discharge pipeline 8. The bottom collection flow rate is 116.9 kg / h, the mass fraction of cyclohexanone in the bottom collection is greater than 99.99%, and the recovery rate of cyclohexanone is above 97.84%.

[0033] Comparative Example 1 Cyclohexanone wastewater was separated using a conventional distillation method.

[0034] Cyclohexanone wastewater was fed into a distillation column at a flow rate of 400 kg / h, with the feed location being the 40th tray from the top of the column, and a reflux ratio of 3. The wastewater contained 38.4% cyclohexanone and 61.6% water by mass. The distillation column was set to an internal pressure of 1 atm, with 60 trays, a top temperature of 97.7℃, and a bottom temperature of 115.9℃. The top product flow rate was 250 kg / h. In the top product, the mass fractions of cyclohexanone and water were 47.1% and 52.9%, respectively. The mass fractions of cyclohexanone and water in the bottom product were 29.6% and 70.3%, respectively.

[0035] Therefore, it is evident that cyclohexanone wastewater cannot be separated using ordinary distillation methods.

[0036] It should be noted that when numerical ranges are involved in this invention, it should be understood that the two endpoints of each numerical range, as well as any value between the two endpoints, can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described in this invention to avoid redundancy. Although preferred embodiments of this invention have been described, those skilled in the art, once they understand the basic inventive concept, can make other changes and modifications to these embodiments, and all such changes and modifications fall within the scope of this invention.

[0037] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. If these modifications and variations fall within the scope of equivalents of this invention, then this invention also intends to include these modifications and variations.

Claims

1. A method for separating cyclohexanone wastewater, the method being based on an extraction separation system comprising an extraction tower (1) and an extractant recovery tower (2), wherein the top outlet of the extraction tower (1) is connected to the extractant recovery tower (2), so that the extract phase in the extraction tower (1) enters the extractant recovery tower (2); the top outlet of the extractant recovery tower (2) is connected to the bottom of the extraction tower (1), so that the extractant separated in the extractant recovery tower (2) is recycled back into the extraction tower (1); characterized in that, The method for separating cyclohexanone wastewater includes the following steps: Using n-propyl acetate as the extractant, n-propyl acetate and cyclohexanone wastewater are fed into an extraction tower (1) for extraction to separate the raffinate phase and the extract phase rich in cyclohexanone and extractant. The extract phase rich in cyclohexanone and extractant is fed into an extractant recovery tower (2). By adjusting the feed flow rate of cyclohexanone wastewater to 400 kg / h to 500 kg / h and the number of trays in the extraction tower (1) to 3 to 5, the feed flow rate of the extract phase rich in cyclohexanone and extractant entering the extractant recovery tower (2) is 500 kg / h to 600 kg / h. According to the feed flow rate of the extractant phase entering the extractant recovery tower (2) being 500 kg / h to 600 kg / h, the reflux ratio of the extractant recovery tower (2) is adjusted to 0.5 to 1.5, and the extractant phase rich in cyclohexanone and extractant is subjected to distillation separation to separate n-propyl acetate and cyclohexanone.

2. The method for separating cyclohexanone wastewater according to claim 1, characterized in that, The mass ratio of cyclohexanone wastewater to extractant is 1:1 to 1.

5.

3. The method for separating cyclohexanone wastewater according to claim 1, characterized in that, The operating temperature of the extraction tower (1) is 25℃~35℃.

4. The method for separating cyclohexanone wastewater according to claim 1, characterized in that, The number of trays in the extractant recovery tower (2) is 15 to 20, the top temperature is 80℃ to 100℃, and the bottom temperature is 160℃ to 165℃.

5. The method for separating cyclohexanone wastewater according to claim 1, characterized in that, In the extraction tower (1), the feed flow rate of the extractant is 500 kg / h to 600 kg / h.

6. The method for separating cyclohexanone wastewater according to claim 1, characterized in that, The mass concentration of cyclohexanone in cyclohexanone wastewater is 33wt% to 50wt%.

7. The method for separating cyclohexanone wastewater according to claim 1, characterized in that, The purity of the cyclohexanone obtained after separation was greater than 99.99%, and the recovery rate of cyclohexanone was greater than 99.18%.

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