Processing high concentration cyclohexane oxidation off-gas systems and methods

Abstract

The application discloses a system and method for treating high-concentration cyclohexane oxidation tail gas. The system comprises an adsorption / desorption module and an absorption / desorption module, and can directly treat high-concentration cyclohexane oxidation tail gas while meeting the gas emission requirements. The system has the advantages of short overall process, high cyclohexane recovery rate, reasonable energy utilization, low energy consumption and the like.

Description

Technical Field

[0001] This invention relates to the field of environmental protection technology, specifically to a system and method for treating high-concentration cyclohexane oxidation tail gas. Background Technology

[0002] The oxidation of cyclohexane to cyclohexanone is a crucial step in the production of caprolactam and is a very important chemical process. This technology uses a large amount of air as the oxidation medium, thus generating tail gas with a high nitrogen content. Furthermore, cyclohexane and the generated cyclohexanol and cyclohexanone are both expensive chemical raw materials or products. Therefore, treating the cyclohexane oxidation tail gas to meet emission standards, while simultaneously recovering cyclohexane and the generated cyclohexanol and cyclohexanone to the greatest extent possible, is crucial for improving the economic efficiency of the process and protecting the environment.

[0003] The current method, involving multiple steps such as condensation and absorption washing, is energy-intensive, yet the exhaust gas still contains 1000 mg / m³ of [unclear - possibly a concentration of pollutants]. 3 The cyclohexane mentioned above does not meet current environmental standards. Introducing powerful adsorption and absorption systems could treat this exhaust gas to meet standards. However, given the existing multiple treatment stages such as condensation, absorption, and scrubbing, this would be redundant and energy-intensive. Summary of the Invention

[0004] The purpose of this invention is to provide a system and method for treating high-concentration cyclohexane oxidation tail gas, which can directly treat high-concentration cyclohexane oxidation tail gas while meeting gas emission requirements. It has the advantages of short overall process, high cyclohexane recovery rate, efficient energy utilization, and low energy consumption.

[0005] To address the aforementioned technical problems, this invention provides a high-concentration cyclohexane oxidation tail gas system, comprising an adsorption / desorption module and an absorption / desorption module. The adsorption / desorption module has a first gas inlet, a first gas outlet, a first cooling medium inlet, a first cooling medium outlet, a first heating medium inlet, and a first heating medium outlet. The absorption / desorption module has a second gas inlet, a second gas outlet, a second cooling medium inlet, a second cooling medium outlet, a second heating medium inlet, and a second heating medium outlet. The first gas outlet of the adsorption / desorption module is connected to the second gas inlet of the absorption / desorption module, and the first cooling medium inlet of the adsorption / desorption module is connected to the second gas outlet of the absorption / desorption module.

[0006] The adsorption / desorption module is filled with an adsorbent, which is a mesoporous carbon adsorbent, and the adsorbent contains 90-98% of the total pore volume of 2-5 nm mesopores.

[0007] The absorption / desorption module is filled with an absorbent, which is an organic hydrocarbon absorbent, with 80% of its components being aromatic substances, a boiling point of 200-350℃, and a freezing point of -25 to -40℃.

[0008] This invention also provides a method for treating cyclohexane oxidation tail gas using the above-mentioned high-concentration cyclohexane oxidation tail gas system, comprising:

[0009] The first step is adsorption and absorption;

[0010] The second step involves desorption, small-scale absorption, and desorption.

[0011] The first step is further specified as follows:

[0012] Step a, cooling medium cooling: The cooling medium is introduced into the second cooling medium inlet and enters the absorption / desorption module. Its temperature is controlled at -20℃ to 40℃. It comes out from the second cooling medium outlet, passes through the first cooling medium inlet and enters the adsorption / desorption module. Its temperature is controlled at -20℃ to 5℃. It is discharged through the first cooling medium outlet.

[0013] Step b: Adsorption and absorption of cyclohexane oxidation tail gas. The tail gas first enters the adsorption / desorption module through the first gas inlet, where it is adsorbed on the mesoporous carbon adsorbent. It then exits the adsorption / desorption module through the first gas outlet. At this point, the total concentration of cyclohexane and heavier molecules in the tail gas is controlled at 100 mg / m³. 3 The exhaust gas is then introduced into the absorption / desorption module through the second gas inlet, where it is absorbed by hydrocarbons as the absorbent. The exhaust gas then exits through the second gas outlet of the absorption / desorption module. At this point, the total concentration of cyclohexane and heavier molecules in the exhaust gas is below 10 mg / m³. 3 .

[0014] The second step is further specified as follows:

[0015] Step a: Heating medium. The heating medium is introduced into the adsorption / desorption module through the first heating medium inlet and its temperature is controlled at 170-240℃. Then the heating medium is discharged from the first heating medium outlet.

[0016] Step b, desorption and small-scale absorption: The organic matter adsorbed on the adsorbent in the adsorption / desorption module is first desorbed at high temperature and normal pressure. The organic gas is discharged from the adsorption / desorption module through the first gas outlet, condensed and collected. When condensation cannot produce liquid, 1-5% of the adsorption operation is introduced into the adsorption / desorption module. During the adsorption operation, the gas from the absorption / desorption module is discharged from the second gas outlet. The temperature is maintained for 2-4 hours to allow the organic matter to continue to desorb. The desorbed gas is then introduced into the second gas inlet of the absorption operation and enters the absorption process.

[0017] Step c, desorption: When the absorbent in the absorption / desorption module is close to saturation, stop the cooling medium of the absorption / desorption module and vent it; then, through the second heating medium inlet, introduce the heating medium into the absorption / desorption module, control its temperature at 150-220℃, and then discharge the heating medium from the second heating medium outlet; the organic matter absorbed in the absorbent in the absorption / desorption module is distilled at atmospheric pressure and exits the absorption / desorption module from the second gas outlet, and is collected after condensation.

[0018] The exhaust gas treated by this invention mainly consists of 1-2% oxygen, 0.02-2% cyclohexane, 0.001-0.02% a mixture of cyclohexanol and cyclohexanone (in any proportion), with the remainder being nitrogen.

[0019] In the method for treating exhaust gas of the present invention, the cooling medium is liquid ammonia or liquid nitrogen, and the heating medium is steam or high-temperature flue gas.

[0020] In the method for treating exhaust gas using the present invention, the recovery rate of cyclohexane in the treated exhaust gas is 95%-98%.

[0021] Beneficial effects of the present invention

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] (1) By utilizing the exhaust gas and the purge gas in the later stage of desorption, nitrogen consumption can be saved by 1-10%.

[0024] (2) Using the cooling medium for adsorption and absorption operations in a gradient from low to high processing temperature can save 5-20% of cooling energy. Replacing the traditional desorption / desorption operation with a small amount of desorption and desorption operation can shorten the desorption time by 10%, improve the desorption effect by 5%, and save 10-30% of heating energy.

[0025] (3) The method of first using adsorption to treat the tail gas has the advantage of high removal rate of organic matter in the tail gas due to the simultaneous use of low temperature and pore structure limitation, which can save 30% of the investment in equipment and absorbent. At the same time, the use of mesoporous adsorbents is easier to regenerate and has lower energy consumption than microporous adsorbents, which reduces the overall cost of adsorbents by 30-50% over long periods of time.

[0026] (4) At the same time, the process of adsorption before absorption avoids the potential harm of the absorbent to the adsorbent, and increases the service life of the adsorbent by 20%-30%. Attached Figure Description

[0027] Figure 1 A schematic diagram of the adsorption and absorption process for treating cyclohexane oxidation tail gas using the high-concentration cyclohexane oxidation tail gas system provided by this invention.

[0028] Figure 2 A schematic diagram of the desorption and desorption process of the high-concentration cyclohexane oxidation tail gas treatment system provided by the present invention. Detailed Implementation

[0029] The following embodiments and accompanying drawings are used to describe in detail the implementation of the present invention, so that the process of how the present invention uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0030] Example 1

[0031] Mesoporous carbon adsorbent (comprising 90% of the total pore volume in 2-5 nm mesopores) is filled in adsorption / desorption module 1. An absorbent (hydrocarbon absorbent with a boiling point of 200-350℃, a freezing point of -40℃, and over 80% aromatics) is filled in absorption / desorption module 2. The first gas outlet 4 of adsorption / desorption module 1 is connected to the second gas inlet 9 of absorption / desorption module 2. The first heating medium outlet 7 of adsorption / desorption module 1 is connected to the second heating medium inlet 11 of absorption / desorption module 2. The first cooling medium inlet 8 of adsorption / desorption module 1 is connected to the second cooling medium outlet 12 of absorption / desorption module 2.

[0032] In adsorption and absorption operations (such as...) Figure 1 As shown, the cooling medium (liquid ammonia) first enters the absorption / desorption module 2 through the second cooling medium inlet 13, and its temperature is controlled at -20℃. Then the cooling medium exits from the second cooling medium outlet 12, passes through the first cooling medium inlet 8 and enters the adsorption / desorption module 1, where its temperature is controlled at -20℃. The cooling medium then exits the adsorption / desorption module 1 from the first cooling medium outlet 6.

[0033] The high-concentration cyclohexane oxidation tail gas (1% oxygen, 0.02% cyclohexane, 0.001% cyclohexanol and cyclohexanone mixture (arbitrary proportions), with the remainder being nitrogen) first enters the adsorption / desorption module 1 through the first gas inlet 3, where it is adsorbed onto a mesoporous adsorbent (made of carbon). This controls the total concentration of cyclohexane and heavier molecules in the tail gas at the first gas outlet 4 of the adsorption / desorption module 1 to be controlled at 100 mg / m³. 3 The exhaust gas is then introduced into the absorption / desorption module 2 through the second gas inlet 9, where it is absorbed by a hydrocarbon absorbent, reducing the total concentration of cyclohexane and heavier molecules in the exhaust gas at the second gas outlet 10 of the absorption / desorption module 2 to 4 mg / m³. 3 .

[0034] Once the above control values ​​are exceeded, desorption and desorption operations will commence (e.g., Figure 2The heating medium (steam) first enters the adsorption / desorption module 1 through the first heating medium inlet 5, and its temperature is controlled at 170℃. Then, the heating medium exits the adsorption / desorption module 1 from the first heating medium outlet 7. The adsorbate (organic matter) on the adsorbent in the adsorption / desorption module 1 is first desorbed at high temperature and normal pressure, and the organic gas exits the adsorption / desorption module 1 from the first gas outlet 4, and is collected after condensation. When condensation cannot yield liquid, 1% of the adsorbed gas is introduced into the adsorption / desorption module 1 through the first gas inlet 3 for purging operation. Figure 2 The desorbed organic gas exits the adsorption / desorption module 1 from the first gas outlet 4 and enters the absorption / desorption module 2 through the second gas inlet 9. Figure 2 ).

[0035] Low-temperature absorption (temperature controlled at -20℃) is performed using the absorbent in the absorption / desorption module, and the absorbed gas exits from the second gas outlet 10. When the concentration of organic matter in the gas exiting the adsorption / desorption module 1 is close to that of the adsorbed gas, desorption is considered complete, and the purging operation is stopped.

[0036] The cooling medium in the absorption / desorption module 2 is discharged from the second cooling medium outlet 12, and the heating medium is introduced through the second heating medium inlet 11, controlling the temperature at 150°C. The heating medium exits the absorption / desorption module 2 from the second heating medium outlet 14. The absorbed organic matter in the absorbent is distilled under normal pressure and exits the absorption / desorption module 2 from the second gas outlet 10, and is collected after condensation.

[0037] Set up two sets as follows Figure 1 , Figure 2 The system shown can simultaneously switch between adsorption / desorption and absorption / desorption, ensuring a continuous process.

[0038] Using the above-described operating apparatus, the recovery rate of cyclohexane can reach 95%.

[0039] Example 2

[0040] Mesoporous carbon adsorbent (containing 98% of the total pore volume in 2-5 nm mesopores) is filled in adsorption / desorption module 1. An absorbent (hydrocarbon absorbent, boiling point 270-350℃, freezing point -40℃, with over 80% aromatics) is filled in absorption / desorption module 2. The first gas outlet 4 of adsorption / desorption module 1 is connected to the second gas inlet 9 of absorption / desorption module 2. The first heating medium outlet 7 of adsorption / desorption module 1 is connected to the second heating medium inlet 11 of absorption / desorption module 2. The first cooling medium inlet 8 of adsorption / desorption module 1 is connected to the second cooling medium outlet 12 of absorption / desorption module 2.

[0041] In adsorption and absorption operations (such as...) Figure 1As shown, the cooling medium (liquid ammonia) first enters the absorption / desorption module 2 through the second cooling medium inlet 13, where its temperature is controlled at -40℃. Then, the cooling medium exits through the second cooling medium outlet 12, passes through the first cooling medium inlet 8, and enters the adsorption / desorption module 1, where its temperature is controlled at 5℃. Finally, the cooling medium exits the adsorption / desorption module 1 through the first cooling medium outlet 6.

[0042] The high-concentration cyclohexane oxidation tail gas (2% oxygen, 2% cyclohexane, 0.02% cyclohexanol and cyclohexanone mixture (arbitrary proportion), with the remainder being nitrogen) first enters the adsorption / desorption module 1 through the first gas inlet 3, where it is adsorbed onto a mesoporous adsorbent (made of carbon). This controls the total concentration of cyclohexane and heavier molecules in the tail gas at the first gas outlet 4 of the adsorption / desorption module 1 to be controlled at 100 mg / m³. 3 The exhaust gas is then introduced into the absorption / desorption module 2 through the second gas inlet 9, where it is absorbed by hydrocarbons as the absorbent, so that the total concentration of cyclohexane and heavier molecules in the exhaust gas at the second gas outlet 10 of the absorption / desorption module 2 is 2 mg / m³. 3 .

[0043] Once the above control values ​​are exceeded, desorption and desorption operations will commence (e.g., Figure 2 The heating medium (flue gas) first enters the adsorption / desorption module 1 through the first heating medium inlet 5, and its temperature is controlled at 240℃. Organic gas exits the adsorption / desorption module 1 from the first gas outlet 4, and is collected after condensation. When condensation fails to yield liquid, 1% adsorption gas is introduced into the adsorption / desorption module 1 through the first gas inlet 3 for purging. Figure 2 The desorbed organic gas exits the adsorption / desorption module 1 from the first gas outlet 4 and enters the absorption / desorption module 2 through the second gas inlet 9. Figure 2 ).

[0044] Low-temperature absorption (temperature controlled at -40℃) is performed using the absorbent in the absorption / desorption module, and the absorbed gas exits from the second gas outlet 10. When the concentration of organic matter in the gas exiting the adsorption / desorption module 1 is close to that of the adsorbed gas, desorption is considered complete, and the purging operation is stopped.

[0045] The cooling medium in the absorption / desorption module 2 is discharged from the second cooling medium outlet 12, and the heating medium is introduced from the second heating medium inlet 11, and the temperature is controlled at 220°C. The heating medium exits the absorption / desorption module 2 from the second heating medium outlet 14.

[0046] Set up two sets as follows Figure 1 , Figure 2 The system shown can simultaneously switch between adsorption / desorption and absorption / desorption, ensuring a continuous process.

[0047] Using the above-described operating apparatus, the recovery rate of cyclohexane can reach 98%.

[0048] Example 3

[0049] Mesoporous carbon adsorbent (containing 95% of the total pore volume in 2-5 nm mesopores) is filled in adsorption / desorption module 1. An absorbent (hydrocarbon absorbent, boiling point 300-350℃, freezing point -25℃, with over 80% aromatics) is filled in absorption / desorption module 2. The first gas outlet 4 of adsorption / desorption module 1 is connected to the second gas inlet 9 of absorption / desorption module 2. The first heating medium outlet 7 of adsorption / desorption module 1 is connected to the second heating medium inlet 11 of absorption / desorption module 2. The first cooling medium inlet 8 of adsorption / desorption module 1 is connected to the second cooling medium outlet 12 of absorption / desorption module 2.

[0050] In adsorption and absorption operations (such as...) Figure 1 As shown, the cooling medium (liquid nitrogen) first enters the absorption / desorption module 2 through the second cooling medium inlet 13, where its temperature is controlled at -40℃. Then, the cooling medium exits through the second cooling medium outlet 12, passes through the first cooling medium inlet 8, and enters the adsorption / desorption module 1, where its temperature is controlled at -10℃. Finally, the cooling medium exits the adsorption / desorption module 1 through the first cooling medium outlet 6.

[0051] The high-concentration cyclohexane oxidation tail gas (1.2% oxygen, 1.2% cyclohexane, 0.015% cyclohexanol and cyclohexanone mixture (arbitrary proportion), with the remainder being nitrogen) first enters the adsorption / desorption module 1 through the first gas inlet 3, where it is adsorbed onto a mesoporous adsorbent (made of carbon). This ensures that the total concentration of cyclohexane and heavy molecules in the tail gas at the first gas outlet 4 of the adsorption / desorption module 1 is controlled at 100 mg / m³. 3 The exhaust gas is then introduced into the absorption / desorption module 2 through the second gas inlet 9, where it is absorbed by hydrocarbons as the absorbent, so that the total concentration of cyclohexane and heavier molecules in the exhaust gas at the second gas outlet 10 of the absorption / desorption module 2 is 7 mg / m³. 3 .

[0052] Once the above control values ​​are exceeded, desorption and desorption operations will commence (e.g., Figure 2 The heating medium (steam) first enters the adsorption / desorption module 1 through the first heating medium inlet 5, and its temperature is controlled at 230℃. Organic gas exits the adsorption / desorption module 1 from the first gas outlet 4, and is collected after condensation. When condensation fails to yield liquid, 1% adsorption gas is introduced into the adsorption / desorption module 1 through the first gas inlet 3 for purging. Figure 2 The desorbed organic gas exits the adsorption / desorption module 1 from the first gas outlet 4 and enters the absorption / desorption module 2 through the second gas inlet 9. Figure 2 ).

[0053] Low-temperature absorption (temperature controlled at -40℃) is performed using the absorbent in the absorption / desorption module, and the absorbed gas exits from the second gas outlet 10. When the concentration of organic matter in the gas exiting the adsorption / desorption module 1 is close to that of the adsorbed gas, desorption is considered complete, and the purging operation is stopped.

[0054] The cooling medium in the absorption / desorption module 2 is discharged from the second cooling medium outlet 12, and the heating medium is introduced from the second heating medium inlet 11, and the temperature is controlled at 200°C. The heating medium exits the absorption / desorption module 2 from the second heating medium outlet 14.

[0055] Set up two sets as follows Figure 1 , Figure 2 The system shown can simultaneously switch between adsorption / desorption and absorption / desorption, ensuring a continuous process.

[0056] Using the above-described operating apparatus, the recovery rate of cyclohexane can reach 97%.

[0057] Example 4

[0058] Mesoporous carbon adsorbent (comprising 97% of the total pore volume in 2-5 nm mesopores) is filled in adsorption / desorption module 1. An absorbent (hydrocarbon absorbent, boiling point 220-300℃, freezing point -35℃, with over 80% aromatics) is filled in absorption / desorption module 2. The first gas outlet 4 of adsorption / desorption module 1 is connected to the second gas inlet 9 of absorption / desorption module 2. The first heating medium outlet 7 of adsorption / desorption module 1 is connected to the second heating medium inlet 11 of absorption / desorption module 2. The first cooling medium inlet 8 of adsorption / desorption module 1 is connected to the second cooling medium outlet 12 of absorption / desorption module 2.

[0059] In adsorption and absorption operations (such as...) Figure 1 As shown, the cooling medium (liquid nitrogen) first enters the absorption / desorption module 2 through the second cooling medium inlet 13, where its temperature is controlled at -25℃. Then, the cooling medium exits through the second cooling medium outlet 12, passes through the first cooling medium inlet 8, and enters the adsorption / desorption module 1, where its temperature is controlled at 0℃. Finally, the cooling medium exits the adsorption / desorption module 1 through the first cooling medium outlet 6.

[0060] The high-concentration cyclohexane oxidation tail gas (1.5% oxygen, 0.5% cyclohexane, 0.02% cyclohexanol and cyclohexanone mixture (arbitrary proportions), with the remainder being nitrogen) first enters the adsorption / desorption module 1 through the first gas inlet 3, where it is adsorbed onto a mesoporous adsorbent (made of carbon). This ensures that the total concentration of cyclohexane and heavier molecules in the tail gas at the first gas outlet 4 of the adsorption / desorption module 1 is controlled at 100 mg / m³. 3The exhaust gas is then introduced into the absorption / desorption module 2 through the second gas inlet 9, where it is absorbed by hydrocarbons as the absorbent, so that the total concentration of cyclohexane and heavier molecules in the exhaust gas at the second gas outlet 10 of the absorption / desorption module 2 is 5 mg / m³. 3 .

[0061] Once the above control values ​​are exceeded, desorption and desorption operations will commence (e.g., Figure 2 The heating medium (steam) first enters the adsorption / desorption module 1 through the first heating medium inlet 5, and its temperature is controlled at 240℃. Organic gas exits the adsorption / desorption module 1 from the first gas outlet 4, and is collected after condensation. When condensation fails to yield liquid, 1% adsorbed gas is introduced into the adsorption / desorption module 1 through the first gas inlet 3 for purging. Figure 2 The desorbed organic gas exits the adsorption / desorption module 1 from the first gas outlet 4 and enters the absorption / desorption module 2 through the second gas inlet 9. Figure 2 ).

[0062] Low-temperature absorption (temperature controlled at -25℃) is performed using the absorbent in the absorption / desorption module, and the absorbed gas exits from the second gas outlet 10. When the concentration of organic matter in the gas exiting the adsorption / desorption module 1 is close to that of the adsorbed gas, desorption is considered complete, and the purging operation is stopped.

[0063] The cooling medium in the absorption / desorption module 2 is discharged from the second cooling medium outlet 12, and the heating medium is introduced from the second heating medium inlet 11, and the temperature is controlled at 220°C. The heating medium exits the absorption / desorption module 2 from the outlet 14.

[0064] Set up two sets as follows Figure 1 , Figure 2 The system shown can simultaneously switch between adsorption / desorption and absorption / desorption, ensuring a continuous process.

[0065] Using the above-described operating apparatus, the recovery rate of cyclohexane can reach 96.5%.

[0066] All of the foregoing primary implementations of this intellectual property right do not limit other forms of implementation of this new product and / or new method. Those skilled in the art will utilize this important information to modify the foregoing to achieve similar implementations. However, all modifications or alterations based on this new product invention are reserved rights.

[0067] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for treating cyclohexane oxidation tail gas, characterized in that, include: The first step is adsorption and absorption; specifically, Step a, cooling medium cooling: The cooling medium is introduced into the second cooling medium inlet and enters the absorption / desorption module. Its temperature is controlled at -20℃ to 40℃. It comes out from the second cooling medium outlet, passes through the first cooling medium inlet and enters the adsorption / desorption module. Its temperature is controlled at -20℃ to 5℃. It is discharged through the first cooling medium outlet. Step b: Adsorption and absorption of cyclohexane oxidation tail gas. The tail gas first enters the adsorption / desorption module through the first gas inlet, where it is adsorbed on the mesoporous carbon adsorbent. It then exits the adsorption / desorption module through the first gas outlet. At this point, the total concentration of cyclohexane and heavier molecules in the tail gas is controlled at 100 mg / m³. 3 The exhaust gas is then introduced into the absorption / desorption module through the second gas inlet, where it is absorbed by a hydrocarbon absorbent. It then exits the absorption / desorption module through the second gas outlet. At this point, the total concentration of cyclohexane and heavier molecules in the exhaust gas is below 10 mg / m³. 3 ; The second step is desorption, involving a small amount of absorption and desorption, specifically... Step a: Heating with the heating medium. The heating medium enters the adsorption / desorption module through the first heating medium inlet, and its temperature is controlled at 170-240℃. Then, the heating medium is discharged from the first heating medium outlet and enters the absorption / desorption module through the second heating medium inlet, where its temperature is controlled at 150-220℃. Then, the heating medium is discharged from the second heating medium outlet. Step b, desorption and small-scale absorption: The organic matter adsorbed on the adsorbent in the adsorption / desorption module is first desorbed at high temperature and normal pressure. The organic gas is discharged from the adsorption / desorption module through the first gas outlet and collected after condensation. When condensation cannot produce liquid, 1-5% of the adsorbed gas is introduced into the first gas inlet of the adsorption / desorption module for purging. The temperature is maintained for 2-4 hours to allow the organic matter on the adsorbent to continue to desorb. The desorbed organic gas exits from the first gas outlet of the absorption / desorption module. Then, it is introduced into the second gas inlet of the absorption operation and absorbed at low temperature by the absorbent in the absorption / desorption module. The temperature is controlled between -20℃ and 40℃. The absorbed gas exits from the second gas outlet. Step c: Desorption. When the absorbent in the absorption / desorption module is close to saturation, the cooling medium is discharged and the heating medium is introduced. The absorbed organic matter is distilled off by atmospheric pressure and exits the absorption / desorption module from the second gas outlet. It is then collected after condensation.

2. The method for treating cyclohexane oxidation tail gas as described in claim 1, characterized in that: This method employs a cyclohexane oxidation tail gas system, which includes an adsorption / desorption module and an absorption / desorption module. The adsorption / desorption module has a first gas inlet, a first gas outlet, a first cooling medium inlet, a first cooling medium outlet, a first heating medium inlet, and a first heating medium outlet. The absorption / desorption module has a second gas inlet, a second gas outlet, a second cooling medium inlet, a second cooling medium outlet, a second heating medium inlet, and a second heating medium outlet. The first gas outlet of the adsorption / desorption module is connected to the second gas inlet of the absorption / desorption module; the first cooling medium inlet of the adsorption / desorption module is connected to the second cooling medium outlet of the absorption / desorption module.

3. The method for treating cyclohexane oxidation tail gas as described in claim 2, characterized in that: The adsorbent in the adsorption / desorption module is a mesoporous carbon adsorbent.

4. The method for treating cyclohexane oxidation tail gas as described in claim 3, characterized in that: The adsorbent comprises 90-98% of the total pore volume in 2-5 nm mesopores.

5. The method for treating cyclohexane oxidation tail gas as described in claim 2, characterized in that: The absorbent in the absorption / desorption module is a hydrocarbon absorbent.

6. The method for treating cyclohexane oxidation tail gas as described in claim 5, characterized in that: The hydrocarbon absorbent has a boiling point of 200-350℃ and a freezing point of -25~-40℃.

7. The method for treating cyclohexane oxidation tail gas as described in claim 1, characterized in that: The cooling medium is liquid ammonia or liquid nitrogen, and the heating medium is steam or high-temperature flue gas.

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