A method and system for ethylene oxide tail gas treatment

Abstract

The application provides an ethylene oxide tail gas treatment method and system, which comprises the following steps: separating ethylene oxide-containing tail gas through an absorption tower, collecting a gas phase stream without ethylene oxide at the top of the tower, and obtaining an ethylene oxide-containing rich absorption liquid phase stream at the bottom of the tower; heating the ethylene oxide-containing rich absorption liquid phase stream through an inlet-outlet heat exchanger to obtain a heated liquid phase stream; heating the heated liquid phase stream through a reactor feed heater to obtain a heated liquid phase stream; regenerating the heated liquid phase stream through a reactor to obtain a lean absorption liquid phase stream; heating the lean absorption liquid phase stream and the ethylene oxide-containing rich absorption liquid phase stream through the inlet-outlet heat exchanger to obtain a cooled lean absorption liquid phase stream; cooling the cooled lean absorption liquid phase stream through a lean absorption liquid cooler to obtain a cooled lean absorption liquid phase stream; and recycling part of the cooled lean absorption liquid phase stream to the absorption tower as an absorption liquid.

Description

Technical Field

[0001] This invention relates to a method and system for treating ethylene oxide tail gas, belonging to the field of chemical process treatment technology. Background Technology

[0002] In 2020, the consumption of carbonate solvents for electrolytes in the Chinese market reached about 200,000 tons, mainly high-end quality. Due to the opportunities brought by new energy, it is predicted that the consumption of carbonate solvents for electrolytes will reach 1.132 million tons in 2025, with broad prospects.

[0003] With the increasing application of lithium batteries, electronic-grade carbonate products, which serve as solvents for lithium battery electrolytes, have a promising future. At the same time, the production of these electronic-grade carbonate products, which uses carbon dioxide as the main raw material, is a carbon emission reduction project.

[0004] Transesterification and methanol oxidative carbonylation are currently the mainstream processes for producing electronic-grade carbonate products. Transesterification is more mature, as its raw materials include CO2, achieving carbon emission reduction. It also offers high selectivity, less corrosiveness to equipment, and simpler waste treatment. Currently, the majority of electronic-grade DMC production capacity in the Chinese market is produced using the transesterification method.

[0005] There are two routes for transesterification: the PO method and the EO method. Currently, the EO method has a certain advantage due to its high profit margin, and the proportion of carbonate production plants using the EO method will continue to increase in the future.

[0006] Although the EO transesterification method (EO method) has the aforementioned advantages over the PO transesterification method (PO method), the EC unit produces multiple exhaust gases, with the highest EO content reaching 19.7 wt%. According to GB31571-2015 "Emission Standard for Pollutants from Petrochemical Industry," the EO content in exhaust gases emitted into the atmosphere must be controlled below 0.5 mg / m³. 3 Therefore, the exhaust gas from carbonate production units using the EO method must be treated before being released into the atmosphere. Furthermore, EO is a flammable and explosive substance with dangerous characteristics such as easy polymerization and an explosive range of 3–100% (pure EO can explode). It is generally not directed towards flares or incinerators, and safety measures must be considered.

[0007] Therefore, finding a suitable method to treat EO exhaust gas is crucial, as it directly affects whether carbonate production units can operate safely and stably. Summary of the Invention

[0008] To address the aforementioned shortcomings and deficiencies, one objective of this invention is to provide a method for treating ethylene oxide tail gas.

[0009] Another object of the present invention is to provide an ethylene oxide tail gas treatment system for implementing the above-described ethylene oxide tail gas treatment method.

[0010] To achieve the above objectives, in one aspect, the present invention provides a method for treating ethylene oxide tail gas, wherein the method includes:

[0011] Step 1: Separate the tail gas containing ethylene oxide through an absorption tower. Collect the gaseous stream without ethylene oxide from the top of the tower, and obtain the ethylene oxide-rich absorbent liquid stream from the bottom of the tower.

[0012] Step 2: The ethylene oxide-rich absorbent liquid phase stream is heat-exchanged through an inlet and outlet heat exchanger to obtain a heated liquid phase stream.

[0013] Step 3: The heated liquid phase stream is heated by the reactor feed heater to obtain a heated liquid phase stream;

[0014] Step 4: The heated liquid phase stream is regenerated by reaction in a reactor to convert ethylene oxide into ethylene glycol, resulting in a lean absorbent liquid phase stream;

[0015] Step 5: Exchange heat between the lean absorbent liquid phase stream and the ethylene oxide-rich absorbent liquid phase stream in the feed heat exchanger. After heat exchange, the cooled lean absorbent liquid phase stream is obtained.

[0016] Step 6: Cool the cooled lean absorbent liquid phase stream through a lean absorbent cooler to obtain a cooled lean absorbent liquid phase stream. Then, circulate a portion of the cooled lean absorbent liquid phase stream back to the absorption tower as absorbent.

[0017] As a specific embodiment of the ethylene oxide tail gas treatment method described above in this invention, the mass percentage of ethylene oxide in the tail gas is 1-5 wt%, with the total mass of the ethylene oxide-containing tail gas being 100%.

[0018] As a specific embodiment of the ethylene oxide tail gas treatment method described above in this invention, step one further includes: discharging the gaseous stream that does not contain ethylene oxide into the atmosphere or sending it to an incinerator for treatment.

[0019] As a specific embodiment of the ethylene oxide tail gas treatment method described above in this invention, in step one, the operating pressure at the top of the absorption tower is 0.001-0.1 MPaG, the theoretical plate number is 5-30, and the operating temperature is 5-40℃.

[0020] In this invention, the ethylene oxide-rich absorbent liquid phase stream does not require an additional stripping tower for regeneration, thus avoiding the generation of higher concentrations of ethylene oxide-containing gas and eliminating the need for further recovery treatment.

[0021] In a specific embodiment of the ethylene oxide tail gas treatment method described above in this invention, in step three, the heated liquid phase stream is heated to the temperature required for reaction and regeneration in the reactor via a reactor feed heater.

[0022] This invention does not impose specific requirements on the heat transfer medium used in the reactor feed heater in step three. It can be reasonably selected according to the actual operation needs, as long as it can ensure that the heated liquid phase stream can be heated to the temperature required for reaction and regeneration in the reactor.

[0023] In a specific embodiment of the ethylene oxide tail gas treatment method described above in this invention, in step four, the reactor is a tubular reactor.

[0024] In one specific embodiment of the ethylene oxide tail gas treatment method described above in this invention, the length of the tubular reactor is 10-100m.

[0025] In a specific embodiment of the ethylene oxide tail gas treatment method described above in this invention, in step four, the operating pressure of the reactor is 0.5-1.5 MPaG, and the reaction regeneration temperature is 100-200℃.

[0026] In this invention, the reactor used in step four does not need to be filled with any catalyst or other media. In the reactor, ethylene oxide and water undergo a non-catalytic hydration reaction to obtain ethylene glycol. The reactor does not require complex control, is risk-free, and is simple and easy to operate.

[0027] In a specific embodiment of the ethylene oxide tail gas treatment method described above in this invention, in step five, the temperature of the cooled lean absorbent liquid phase stream is 5-40°C.

[0028] This invention does not specify the temperature of the liquid phase stream after heating in step two or the temperature of the lean absorbent liquid phase stream after cooling in step five; the goal is to maximize the recovery of heat from the lean absorbent liquid phase stream. In step five, the lean absorbent liquid phase stream and the ethylene oxide-containing rich absorbent liquid phase stream exchange heat in the inlet and outlet heat exchangers, saving heat and cooling energy consumption.

[0029] In a specific embodiment of the ethylene oxide tail gas treatment method described above in this invention, in step six, the cooling medium used in the lean absorbent cooler includes circulating cooling water or chilled water.

[0030] In the ethylene oxide tail gas treatment method described above in this invention, during the initial start-up phase, an ethylene glycol aqueous solution can be filled into the absorption tower as an absorbent. Furthermore, this invention does not impose specific requirements on the concentration of the ethylene glycol aqueous solution, etc., and can be reasonably adjusted according to the actual on-site operation needs. After the heated liquid phase stream is regenerated by the reactor reaction, the cooled lean absorbent liquid phase stream is recycled back to the absorption tower as an absorbent.

[0031] In step six of this invention, a portion of the cooled lean absorbent liquid phase stream, i.e., an aqueous solution containing ethylene glycol, is recycled back to the absorber as the absorbent. There is no need to introduce additional absorbent, and the ethylene glycol produced by the reaction itself is used as the absorbent. There is no need to set up an additional separation tower or regeneration tower.

[0032] In a specific embodiment of the ethylene oxide tail gas treatment method described above in this invention, step six further includes discharging another portion of the cooled lean absorbent liquid phase stream as a product or waste liquid. This cooled lean absorbent liquid phase stream does not contain ethylene oxide and is easy to handle.

[0033] As a specific embodiment of the ethylene oxide tail gas treatment method described above in this invention, the ethylene oxide tail gas is the tail gas produced by the carbonate unit.

[0034] On the other hand, the present invention also provides an ethylene oxide tail gas treatment system for implementing the above-described ethylene oxide tail gas treatment method, wherein the ethylene oxide tail gas treatment system includes: an ethylene oxide tail gas input pipeline, an absorption tower, a reactor, an inlet and outlet heat exchanger, a reactor feed heater, and a lean absorbent cooler.

[0035] The absorption tower is provided with a gas inlet, an absorbent liquid inlet, a gas outlet, and a rich absorbent liquid outlet at the lower part of the tower wall, the upper part of the tower wall, the top of the tower, and the bottom of the tower, respectively.

[0036] The ethylene oxide tail gas input pipeline is connected to the gas inlet. The rich absorbent outlet is connected to the cold side inlet of the feed heat exchanger via a pipeline. The cold side outlet of the feed heat exchanger is connected to the reactor inlet via a pipeline through the reactor feed heater. The reactor outlet is connected to the hot side inlet of the feed heat exchanger via a pipeline. The hot side outlet of the feed heat exchanger is connected to the absorbent inlet via a pipeline through the lean absorbent cooler.

[0037] In this invention, the absorption tower, reactor, feed heat exchanger, reactor feed heater, and lean absorbent cooler are all conventional equipment that can be purchased commercially.

[0038] Compared with the prior art, the beneficial technical effects achieved by the present invention include:

[0039] 1) The ethylene oxide-containing tail gas treated by this invention does not contain ethylene oxide and can be discharged into the atmosphere or sent to an incinerator for treatment;

[0040] 2) This invention can recycle part of the cooled lean absorbent liquid phase stream, i.e., the aqueous solution containing ethylene glycol, back to the absorption tower as absorbent without the need for additional absorbent, thus reducing the amount of fresh water required for external replenishment; and when the other part of the cooled lean absorbent liquid phase stream is discharged as product or waste liquid, since the waste absorbent does not contain ethylene oxide, it is easy to further process.

[0041] 3) This invention does not generate additional ethylene oxide-rich gas and does not require further processing by other facilities;

[0042] 4) In the process of treating ethylene oxide-containing tail gas, the present invention converts the ethylene oxide in the tail gas into ethylene glycol, and the waste absorbent can be sold as a product.

[0043] In summary, the method and system provided by this invention utilize a combination of absorption and reaction regeneration technology to treat ethylene oxide tail gas, effectively solving the technical problem of difficult treatment of ethylene oxide tail gas, such as ethylene oxide tail gas from carbonate plants. This achieves compliant emissions of ethylene oxide-containing tail gas, while the lean absorbent can be recycled as absorbent, reducing the amount of fresh water used. Furthermore, the waste absorbent does not contain ethylene oxide and is easy to treat. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 This is a schematic diagram of the ethylene oxide tail gas treatment system provided in Embodiment 1 of the present invention.

[0046] Explanation of main icon numbers:

[0047] T1 - Absorption tower, R1 - Reactor;

[0048] E1 - Feed and discharge heat exchangers, E2 - Reactor feed heater, E3 - Lean absorbent cooler;

[0049] S1 represents tail gas containing ethylene oxide, S2 represents fresh water, S3 represents gaseous stream without ethylene oxide, S4 represents liquid stream rich in ethylene oxide absorbent, S5 represents liquid stream rich in ethylene oxide absorbent after heating, S6 represents liquid stream rich in ethylene oxide absorbent after heating, S7 represents liquid stream lean absorbent, S8 represents liquid stream lean absorbent after cooling, S9 represents liquid stream recycled lean absorbent, and S10 represents liquid stream waste absorbent. Detailed Implementation

[0050] It should be noted that the term "comprising" and any variations thereof in the specification, claims, and accompanying drawings of this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0051] The "range" disclosed in this invention is given in the form of a lower limit and an upper limit. It can be one or more lower limits and one or more upper limits, respectively. A given range is defined by selecting a lower limit and an upper limit. The selected lower and upper limits define the boundaries of the particular range. All ranges defined in this way are composable, meaning that any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for specific parameters, it is also expected that ranges of 60-110 and 80-120 are also expected. Furthermore, if the listed minimum range values ​​are 1 and 2, and the listed maximum range values ​​are 3, 4, and 5, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.

[0052] In this invention, unless otherwise specified, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this invention, and "0-5" is simply a shortened representation of these numerical combinations.

[0053] In this invention, unless otherwise specified, all embodiments and preferred embodiments mentioned in this invention can be combined with each other to form new technical solutions.

[0054] In this invention, unless otherwise specified, all technical features and preferred features mentioned in this invention can be combined with each other to form new technical solutions.

[0055] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying tables, drawings, and embodiments. The embodiments described below are some, but not all, embodiments of this invention, and are only used to illustrate the invention, and should not be considered as limiting the scope of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0056] Example 1

[0057] This embodiment provides an ethylene oxide tail gas treatment system, the structural schematic diagram of which is shown below. Figure 1 As shown, from Figure 1 As can be seen from the above, the ethylene oxide tail gas treatment system includes:

[0058] Ethylene oxide tail gas inlet pipeline, absorption tower T1, reactor R1, feed heat exchanger E1, reactor feed heater E2, and lean absorbent cooler E3;

[0059] The absorption tower T1 is provided with a gas inlet, an absorbent liquid inlet, a gas outlet, and a rich absorbent liquid outlet at the lower part of the tower wall, the upper part of the tower wall, the top of the tower, and the bottom of the tower, respectively.

[0060] The ethylene oxide tail gas input pipeline is connected to the gas inlet. The rich absorbent outlet is connected to the cold side inlet of the feed heat exchanger E1 via a pipeline. The cold side outlet of the feed heat exchanger E1 is connected to the inlet of the reactor R1 via the reactor feed heater E2 via a pipeline. The outlet of the reactor R1 is connected to the hot side inlet of the feed heat exchanger E1 via a pipeline. The hot side outlet of the feed heat exchanger E1 is connected to the absorbent inlet via the lean absorbent cooler E3 via a pipeline.

[0061] In this embodiment, the reactor is a tubular reactor.

[0062] Example 2

[0063] This embodiment provides a method for treating ethylene oxide tail gas, which is implemented using the ethylene oxide tail gas treatment system provided in Example 1. The method includes the following specific steps:

[0064] Step 1: Separate the tail gas containing ethylene oxide S1 through the absorption tower T1. The gas phase stream S3 without ethylene oxide is collected from the top of the tower, and the liquid phase stream S4 containing ethylene oxide is obtained from the bottom of the tower.

[0065] The ethylene oxide-containing tail gas S1 is the tail gas produced by a 260,000-ton / year integrated carbonate plant, with a flow rate of 6,000 kg / h and a mass composition of: 2% ethylene oxide, 0.03% ethylene carbonate, 4% air, and 93.97% other components; the absorption tower T1 has 11 theoretical plates, an operating pressure of 0.003 MPaG at the top of the tower, and an operating temperature of 40℃;

[0066] Step 2: Discharge the ethylene oxide-free gaseous stream S3 obtained in Step 1 into the atmosphere or send it to an incinerator for treatment;

[0067] Step 3: The ethylene oxide-rich absorbent liquid stream S4 obtained in Step 1 is heat-exchanged through the feed heat exchanger E1 to obtain the heated liquid stream S5, which has a temperature of 150℃.

[0068] Step 4: The heated liquid stream S5 obtained in Step 3 is heated by the reactor feed heater E2 to obtain the heated liquid stream S6 at a temperature of 160℃.

[0069] Step 5: The heated liquid phase stream S6 obtained in Step 4 is regenerated by reactor R1 to convert ethylene oxide into ethylene glycol, resulting in lean absorbent liquid phase stream S7.

[0070] The operating pressure of reactor R1 is 0.8 MPaG, the reaction regeneration temperature is 160℃, and the length of the reactor is 75m.

[0071] Step 6: The lean absorbent liquid phase stream S7 obtained in Step 5 is heat-exchanged with the ethylene oxide-containing rich absorbent liquid phase stream S4 in the feed heat exchanger E1. After the heat exchange, the cooled lean absorbent liquid phase stream S8 is obtained at a temperature of 50℃.

[0072] Step 7: Cool the cooled lean absorbent liquid phase stream S8 through lean absorbent cooler E3 to obtain a cooled lean absorbent liquid phase stream with a temperature of 40℃.

[0073] Step 8: Then, a portion of the cooled lean absorbent liquid phase stream, i.e., the circulating lean absorbent liquid phase stream S9, is recycled back to the absorber tower T1 as the absorbent. In the absorber tower T1, the ethylene oxide tail gas S1 comes into countercurrent contact with the circulating lean absorbent liquid phase stream S9, and the ethylene oxide in the tail gas is absorbed.

[0074] Step 9: Discharge the other part of the cooled lean absorbent liquid phase stream, i.e. waste absorbent liquid phase stream S10, as a product or waste liquid.

[0075] In this embodiment, the ethylene oxide content in the gaseous stream S3 obtained in step one is less than 1 ppm, and it can be discharged into the atmosphere or sent to an incinerator for treatment; the waste absorbent liquid stream S10 obtained in step nine is a 30 wt% ethylene glycol aqueous solution, which does not contain ethylene oxide and can be sent to an incinerator for treatment.

[0076] Example 3

[0077] This embodiment provides a method for treating ethylene oxide tail gas, which is implemented using the ethylene oxide tail gas treatment system provided in Example 1. The method includes the following specific steps:

[0078] Step 1: Separate the tail gas containing ethylene oxide S1 through the absorption tower T1. The gas phase stream S3 without ethylene oxide is collected from the top of the tower, and the liquid phase stream S4 containing ethylene oxide is obtained from the bottom of the tower.

[0079] The ethylene oxide tail gas S1 is the tail gas produced by a 100,000-ton / year ethylene carbonate plant, with a flow rate of 3000 kg / h and a mass composition of 2.5% ethylene oxide, 1% ethylene carbonate, 6% air, and 90.5% other components. The absorption tower T1 has 20 theoretical plates, an operating pressure of 0.05 MPaG at the top of the tower, and an operating temperature of 5°C.

[0080] Step 2: Discharge the ethylene oxide-free gaseous stream S3 obtained in Step 1 into the atmosphere or send it to an incinerator for treatment;

[0081] Step 3: The ethylene oxide-rich absorbent liquid phase stream S4 obtained in Step 1 and the fresh water S2 are passed together through the feed heat exchanger E1 to obtain the heated liquid phase stream S5, which has a temperature of 190℃.

[0082] Step 4: The heated liquid stream S5 obtained in Step 3 is heated by the reactor feed heater E2 to obtain the heated liquid stream S6 at a temperature of 200℃.

[0083] Step 5: The heated liquid phase stream S6 obtained in Step 4 is regenerated by reactor R1 to convert ethylene oxide into ethylene glycol, resulting in lean absorbent liquid phase stream S7.

[0084] The reactor R1 operates at a pressure of 1.0 MPaG, regeneration temperature of 200℃, and is 90 m long.

[0085] Step 6: The lean absorbent liquid phase stream S7 obtained in Step 5 is heat-exchanged with the ethylene oxide-containing rich absorbent liquid phase stream S4 in the feed heat exchanger E1. After the heat exchange, the cooled lean absorbent liquid phase stream S8 is obtained with a temperature of 15℃.

[0086] Step 7: Cool the cooled lean absorbent liquid phase stream S8 through lean absorbent cooler E3 to obtain a cooled lean absorbent liquid phase stream with a temperature of 5℃.

[0087] Step 8: Then, a portion of the cooled lean absorbent liquid phase stream, i.e., the circulating lean absorbent liquid phase stream S9, is recycled back to the absorber tower T1 as the absorbent. In the absorber tower T1, the ethylene oxide tail gas S1 comes into countercurrent contact with the circulating lean absorbent liquid phase stream S9, and the ethylene oxide in the tail gas is absorbed.

[0088] Step 9: Discharge the other part of the cooled lean absorbent liquid phase stream, i.e. waste absorbent liquid phase stream S10, as a product or waste liquid.

[0089] In this embodiment, the ethylene oxide content in the gaseous stream S3 obtained in step one is less than 1 ppm, and it can be discharged into the atmosphere or sent to an incinerator for treatment; the waste absorbent liquid stream S10 obtained in step nine is a 40 wt% ethylene glycol aqueous solution, which does not contain ethylene oxide and can be sent to an incinerator for treatment.

[0090] In summary, the method and system provided in this invention utilize a combination of absorption and reaction regeneration technology to treat ethylene oxide tail gas, effectively solving the technical problem of difficult treatment of ethylene oxide tail gas, such as ethylene oxide tail gas from carbonate plants. This achieves compliant emissions of ethylene oxide-containing tail gas, while the lean absorbent can be recycled as absorbent, reducing the amount of fresh water used. Furthermore, the waste absorbent does not contain ethylene oxide and is easy to treat.

[0091] The above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, any substitution of equivalent components or equivalent changes and modifications made within the scope of protection of this patent should still fall within the scope of this patent. Furthermore, the technical features, technical features and technical inventions, and technical inventions in this invention can be freely combined and used.

Claims

1. A method for treating ethylene oxide tail gas, characterized in that, The ethylene oxide tail gas treatment method includes: Step 1: Separate the ethylene oxide-containing tail gas through an absorption tower. Collect the gaseous stream without ethylene oxide from the top of the tower, and obtain the ethylene oxide-rich absorbent liquid stream from the bottom of the tower. The operating pressure at the top of the absorption tower is 0.001-0.1 MPaG, the theoretical plate number is 5-30, and the operating temperature is 5-40℃. Step 2: The ethylene oxide-rich absorbent liquid phase stream is heat-exchanged through an inlet and outlet heat exchanger to obtain a heated liquid phase stream. Step 3: The heated liquid phase stream is heated by the reactor feed heater to obtain a heated liquid phase stream; Step 4: The heated liquid phase stream is regenerated in a reactor to convert ethylene oxide into ethylene glycol, resulting in a lean absorbent liquid phase stream; wherein, the reactor operating pressure is 0.5-1.5 MPaG, and the reaction regeneration temperature is 100-200℃; Step 5: Exchange heat between the lean absorbent liquid phase stream and the ethylene oxide-rich absorbent liquid phase stream in the feed heat exchanger. After heat exchange, a cooled lean absorbent liquid phase stream is obtained. The temperature of the cooled lean absorbent liquid phase stream is 5-40℃. Step 6: Cool the cooled lean absorbent liquid phase stream through a lean absorbent cooler to obtain a cooled lean absorbent liquid phase stream. Then, circulate a portion of the cooled lean absorbent liquid phase stream back to the absorption tower as absorbent.

2. The method for treating ethylene oxide tail gas according to claim 1, characterized in that, Step one also includes: releasing the gaseous stream containing no ethylene oxide into the atmosphere or sending it to an incinerator for treatment.

3. The method for treating ethylene oxide tail gas according to claim 1 or 2, characterized in that, Based on the total mass of the ethylene oxide-containing tail gas as 100%, the mass percentage of ethylene oxide is 1-5 wt%.

4. The method for treating ethylene oxide tail gas according to claim 1, characterized in that, In step three, the heated liquid phase stream is heated to the temperature required for reaction and regeneration inside the reactor by the reactor feed heater.

5. The method for treating ethylene oxide tail gas according to claim 1, characterized in that, In step four, the reactor is a tubular reactor.

6. The method for treating ethylene oxide tail gas according to claim 5, characterized in that, The tubular reactor has a length of 10-100m.

7. The method for treating ethylene oxide tail gas according to claim 1, characterized in that, In step six, the cooling medium used in the lean absorber cooler includes circulating cooling water or chilled water.

8. The method for treating ethylene oxide tail gas according to claim 1 or 7, characterized in that, Step six also includes discharging another portion of the cooled lean absorbent liquid phase stream as a product or waste liquid.

9. The method for treating ethylene oxide tail gas according to any one of claims 1-2 and 4-7, characterized in that, The ethylene oxide-containing tail gas is the tail gas produced by the carbonate unit.

10. An ethylene oxide tail gas treatment system for implementing the ethylene oxide tail gas treatment method according to any one of claims 1-9, characterized in that, The ethylene oxide tail gas treatment system includes: an ethylene oxide tail gas input pipeline, an absorption tower, a reactor, an inlet and outlet heat exchanger, a reactor feed heater, and a lean absorbent cooler. The absorption tower is provided with a gas inlet, an absorbent liquid inlet, a gas outlet, and a rich absorbent liquid outlet at the lower part of the tower wall, the upper part of the tower wall, the top of the tower, and the bottom of the tower, respectively. The ethylene oxide tail gas input pipeline is connected to the gas inlet. The rich absorbent outlet is connected to the cold side inlet of the feed heat exchanger via a pipeline. The cold side outlet of the feed heat exchanger is connected to the reactor inlet via a pipeline through the reactor feed heater. The reactor outlet is connected to the hot side inlet of the feed heat exchanger via a pipeline. The hot side outlet of the feed heat exchanger is connected to the absorbent inlet via a pipeline through the lean absorbent cooler.

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