Ethylene oxide gas preparation method
By using a modified epoxy catalyst to produce ethylene oxide in an epoxidation reactor, and combining this with the use of separation and purification towers, the problems of high ethylene feedstock consumption and environmental pollution have been solved, achieving efficient and low-cost production of ethylene oxide.
Patent Information
- Application Number
- CN202511517319.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-23
- Publication Date
- 2026-01-02
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
In existing ethylene oxide production methods, ethylene feedstock consumption accounts for most of the cost, and traditional methods also cause environmental pollution. Therefore, it is necessary to find efficient and environmentally friendly production processes to reduce costs and pollution.
The modified epoxy catalyst, including metallic zirconium oxide and oxidized zirconium oxide and yttrium oxide as co-catalysts, is introduced into the modified epoxidation reactor and generated under the action of the catalyst. It is then further purified by a separation system and a purification tower, and finally stored in a gas cylinder storage.
This improved the utilization rate of ethylene, reduced production costs, and decreased environmental pollution, thus achieving efficient preparation of ethylene oxide.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of ethylene oxide production technology, and specifically to a method for preparing ethylene oxide gas. Background Technology
[0002] Ethylene oxide is an important derivative of the ethylene industry, playing a crucial role in the national economy. It is obtained through the direct reaction of ethylene and oxygen, and can be used to produce ethylene glycol, which is further used in the production of pharmaceuticals, antifreeze plastics, and detergents. Furthermore, ethylene oxide is a raw material for the production of pharmaceutical intermediates, pesticide emulsifiers, anti-corrosion coatings, and surfactants.
[0003] To date, the main methods for producing ethylene oxide include the chlorohydrin process and the direct oxidation of ethylene. The chlorohydrin process involves the reaction of ethylene and chlorine in water to produce hypochlorous acid, which then oxidizes the ethylene to ethylene oxide and calcium chloride. The mixture is subsequently refined using stripping technology to obtain high-purity ethylene oxide. While the chlorohydrin process has a high utilization rate of the ethylene feedstock, the presence of chlorine in the reaction generates large amounts of acidic waste gas and wastewater, posing significant challenges to waste treatment and causing environmental harm. With increasing environmental awareness, this method has been gradually abandoned.
[0004] The direct oxidation of ethylene uses more environmentally friendly ethylene and oxygen as raw materials. The reaction occurs under catalysis, high pressure, and high temperature to produce ethylene oxide. This method produces only small amounts of aldehydes and carbon dioxide as byproducts, and therefore, it is gradually replacing the chlorohydrin process as the mainstream production method. However, in the industrial production of ethylene oxide through ethylene oxidation, the consumption of ethylene raw materials accounts for approximately 70% of the production cost. Therefore, reducing the consumption of ethylene raw materials has become one of the key aspects of improving the economic efficiency of ethylene oxide products. Summary of the Invention
[0005] To address the problems existing in the background technology, the present invention provides a method for preparing ethylene oxide gas, comprising the following preparation steps:
[0006] Step (1): Check the biogas tightness of the pipeline, then filter the oxygen and pass it into the mixing station. After the ethylene is desulfurized, it is mixed with oxygen to form a reaction gas. The reaction gas is preheated in the gas-to-gas heat exchanger and then passed into the epoxidation reactor containing modified epoxy catalyst at 70°C. At the outlet of the epoxidation reactor, a mixed gas containing ethylene oxide and water are generated to form a dilute solution.
[0007] Step (2): A dilute solution of a mixed gas containing ethylene oxide and water is introduced into the ethylene oxide separation system. The solution is indirectly heated by medium-pressure steam from the bottom heater of the tower, so that the ethylene oxide is extracted from the aqueous solution. Then, the mixed gas containing ethylene oxide is contacted with CO2 removed from the circulating gas of the activated hot potassium alkali process to separate the ethylene oxide from other impurity gases. Finally, the ethylene oxide gas is condensed into a liquid through a condenser.
[0008] Step (3): The liquefied ethylene oxide is fed into the reabsorption stripping system. Absorption water is added from the top of the tower to absorb the ethylene oxide at the bottom. When passing through the upper packing, the vaporized ethylene oxide is fully absorbed.
[0009] Step (4): Add high concentrations of ethylene oxide to the refining tower and carbon dioxide stripping tower to further remove residual formaldehyde from the dissolved liquid phase;
[0010] Step (5): The prepared ethylene oxide is passed into a steel cylinder and stored in a cool, ventilated Class A gas cylinder warehouse.
[0011] Preferably, in step (1), the inlet gas flow concentration is controlled as follows: ethylene 30.23%, oxygen 7.05%, and the remainder is stabilized with nitrogen.
[0012] A method for preparing ethylene oxide gas, wherein the modified epoxy catalyst comprises:
[0013] S1: Preparation of α-alumina support;
[0014] S2: Under argon protection, add 1-2 wt% of natural rubber binder and modified alumina carrier to the impregnation solution, stir for 30-40 minutes, mix evenly, and filter to obtain filter residue;
[0015] S3: Dry the filter residue at 150~200Kpa, 150~200℃, and under argon protection for 1~1.5 hours; cool to room temperature, introduce air into the furnace, and activate for 1~1.5 hours to obtain the modified epoxy catalyst.
[0016] More preferably, the preparation steps of the modified α-alumina carrier are as follows: α-alumina powder is placed in a 0.1 mol / L hydrofluoric acid solution and soaked for 4-5 hours. After filtration, it is rinsed three times with purified water, dried by blowing air for 1-1.5 hours, and repeated three times. The powder is then ground to obtain α-alumina particles with an average particle size of 3-4 mm.
[0017] More preferably, the impregnation solution is composed of 15-20 parts tetramethylammonium fluoride, 35-45 parts deionized water, 40-45 parts silver ammonia complex, 1-10 parts zirconium oxide, and 1-10 parts yttrium oxide.
[0018] More preferably, the silver amine complex preparation steps are as follows: 1% sodium citrate is added to boiling silver nitrate and stirred continuously for 1 hour to prepare silver citrate; cysteine is dissolved in deionized water to obtain a cysteine aqueous solution; the prepared silver citrate solution and the cysteine aqueous solution are mixed at 1:1 at 80-90℃ and reacted for 30 minutes; then sodium hydroxide solution is added dropwise to adjust the pH to 7-8 to form a silver amine complex.
[0019] Preferably, the upper packing is a ceramic rectangular saddle ring.
[0020] Preferably, in step (5), the temperature in the gas cylinder storage room is controlled below 30°C, the storage room is kept away from fire and heat sources, avoids light, avoids storage with acids, alkalis, alcohols and food chemicals, and is equipped with explosion-proof lighting and ventilation facilities.
[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0022] In the industrial production of ethylene oxide through ethylene oxidation, the consumption of ethylene feedstock accounts for the majority of the production cost. This invention provides a method for producing ethylene oxide, along with a novel catalyst. The addition of small amounts of zirconium oxide and yttrium oxide as co-catalysts effectively disperses silver particles, improves catalyst stability, extends its lifespan, accelerates the epoxidation reaction, enhances the competitiveness of the main reaction, and increases the selectivity of ethylene oxide, significantly improving ethylene utilization. Detailed Implementation
[0023] The embodiments of the technical solution of the present invention will be described in detail below with reference to the examples. The following embodiments are only used to illustrate the technical solution of the present invention more clearly, and are therefore only examples, and should not be used to limit the scope of protection of the present invention.
[0024] It should be noted that, unless otherwise specified, the experimental methods used in the implementation examples are all conventional methods; and the materials and reagents used are all commercially available unless otherwise specified.
[0025] In this invention, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0~5" means that all real numbers between "0~5" have been listed in this document, and "0~5" is simply a shortened representation of these numerical combinations.
[0026] In this invention, unless otherwise specified, all embodiments and preferred embodiments mentioned herein can be combined to form new technical solutions.
[0027] In this invention, unless otherwise specified, all steps mentioned herein may be performed sequentially or randomly, but are preferably performed sequentially; for example, the method includes steps (1) and (2), indicating that the method may include steps (1) and (2) performed sequentially, or may include steps (2) and (1) performed sequentially; for example, the method may also include step (3), indicating that step (3) may be added to the method in any order, for example, the method may include steps (1), (2) and (3), or may include steps (1), (3) and (2), or may include steps (3), (1) and (2), etc.
[0028] In this invention, unless otherwise specified, the specific values and substances in the embodiments herein can be combined with other features described herein; for example, if the specification mentions a reaction temperature of 10~100°C, while the embodiment mentions a reaction temperature of 20°C, then it can be considered that the range of 10~20°C or 20~100°C has been specifically disclosed herein, and this range can be combined with other features described herein to form a new technical solution.
[0029] Example 1
[0030] Preparation of modified epoxy catalysts
[0031] S1: Preparation of α-alumina support;
[0032] The α-alumina powder was placed in a 0.1 mol / L hydrofluoric acid solution and soaked for 4 hours. After filtration, it was rinsed three times with purified water and dried by blowing air for 1.5 hours. This process was repeated three times, and the powder was ground to obtain α-alumina particles with an average particle size of 3-4 mm.
[0033] S2: Impregnation;
[0034] Silver citrate was prepared by adding 1% sodium citrate to boiling silver nitrate under argon protection and stirring continuously for 1 hour.
[0035] Cysteine was dissolved in deionized water to obtain an aqueous solution of cysteine. At 80°C, the prepared silver citrate solution and the aqueous solution of cysteine were mixed at a ratio of 1:1 and reacted for 30 minutes. Then, sodium hydroxide solution was added dropwise to adjust the pH to 7-8, forming a silver amine complex.
[0036] Add 18 parts of tetramethylammonium fluoride to 40 parts of deionized water and stir thoroughly to prepare an aqueous solution of tetramethylammonium fluoride. Add the aqueous solution of tetramethylammonium fluoride to 40 parts of silver ammonia complex, and then add 1 part of zirconium oxide and 1 part of yttrium oxide. Stir thoroughly to obtain an impregnation solution.
[0037] Add 1 wt% natural rubber binder and modified alumina carrier to the impregnation solution, stir for 35 minutes, mix evenly, and filter to obtain filter residue;
[0038] S3: Drying and activation;
[0039] The filter residue was dried at 150 kPa, 200 °C, and under argon protection for 1.5 h. After cooling to room temperature, air was introduced into the furnace and activated for 1.5 h to obtain modified epoxy catalyst 1.
[0040] Step (1): Check the biogas tightness of the pipeline, then filter the oxygen and pass it into the mixing station. After the ethylene is desulfurized, it is mixed with oxygen to form a reaction gas with ethylene 30.23% and oxygen 7.05%. The reaction gas is preheated in the gas-to-gas heat exchanger and passed into the epoxidation reactor containing modified epoxy catalyst 1 at 70°C. At the outlet of the epoxidation reactor, a mixed gas containing ethylene oxide and water are generated to form a dilute solution.
[0041] Step (2): A dilute solution of a mixed gas containing ethylene oxide and water is introduced into the ethylene oxide separation system. The solution is indirectly heated by medium-pressure steam from the bottom heater of the tower, so that the ethylene oxide is extracted from the aqueous solution. Then, the mixed gas containing ethylene oxide is contacted with CO2 removed from the circulating gas of the activated hot potassium alkali process to separate the ethylene oxide from other impurity gases. Finally, the ethylene oxide gas is condensed into a liquid through a condenser.
[0042] Step (3): The liquefied ethylene oxide is fed into the reabsorption stripping system. Absorption water is added from the top of the tower to absorb the ethylene oxide at the bottom. When it passes through the upper packing ceramic rectangular saddle ring, the vaporized ethylene oxide is fully absorbed.
[0043] Step (4): Add high concentrations of ethylene oxide to the refining tower and carbon dioxide stripping tower to further remove residual formaldehyde from the dissolved liquid phase;
[0044] Step (5): The prepared ethylene oxide is passed into a steel cylinder and stored in a cool, ventilated Class A gas cylinder warehouse. The temperature in the gas cylinder warehouse is controlled below 30°C. The warehouse is far away from fire and heat sources, avoids light, and avoids storage with acids, alkalis, alcohols, and food chemicals. Explosion-proof lighting and ventilation facilities are installed in the warehouse.
[0045] Example 2
[0046] Preparation of modified epoxy catalysts
[0047] S1: Preparation of α-alumina support;
[0048] The α-alumina powder was placed in a 0.1 mol / L hydrofluoric acid solution and soaked for 5 hours. After filtration, it was rinsed three times with purified water and dried by blowing air for 1.5 hours. This process was repeated three times, and the powder was ground to obtain α-alumina particles with an average particle size of 3-4 mm.
[0049] S2: Impregnation;
[0050] Silver citrate was prepared by adding 1% sodium citrate to boiling silver nitrate under argon protection and stirring continuously for 1 hour.
[0051] Cysteine was dissolved in deionized water to obtain an aqueous solution of cysteine. At 90°C, the prepared silver citrate solution and the aqueous solution of cysteine were mixed at a ratio of 1:1 and reacted for 30 minutes. Then, sodium hydroxide solution was added dropwise to adjust the pH to 7-8, forming a silver amine complex.
[0052] Add 15 parts of tetramethylammonium fluoride to 38 parts of deionized water and stir thoroughly to prepare an aqueous solution of tetramethylammonium fluoride. Add the aqueous solution of tetramethylammonium fluoride to 40 parts of silver ammonia complex, and then add 3 parts of zirconium oxide and 4 parts of yttrium oxide. Stir thoroughly to obtain an impregnation solution.
[0053] Add 2wt% natural rubber binder and modified alumina carrier to the impregnation solution, stir for 40 minutes, mix evenly, and filter to obtain filter residue;
[0054] S3: Drying and activation;
[0055] The filter residue was dried at 200 kPa and 200 °C under argon protection for 1.5 h; after cooling to room temperature, air was introduced into the furnace and activated for 1.5 h to obtain modified epoxy catalyst 2.
[0056] Step (1): Check the biogas tightness of the pipeline, then filter the oxygen and pass it into the mixing station. After the ethylene is desulfurized, it is mixed with oxygen to form a reaction gas with ethylene 30.23% and oxygen 7.05%. The reaction gas is preheated in the gas-to-gas heat exchanger and then passed into the epoxidation reactor containing modified epoxy catalyst 2 at 70°C. At the outlet of the epoxidation reactor, a mixed gas containing ethylene oxide and water are generated to form a dilute solution.
[0057] Step (2): A dilute solution of a mixed gas containing ethylene oxide and water is introduced into the ethylene oxide separation system. The solution is indirectly heated by medium-pressure steam from the bottom heater of the tower, so that the ethylene oxide is extracted from the aqueous solution. Then, the mixed gas containing ethylene oxide is contacted with CO2 removed from the circulating gas of the activated hot potassium alkali process to separate the ethylene oxide from other impurity gases. Finally, the ethylene oxide gas is condensed into a liquid through a condenser.
[0058] Step (3): The liquefied ethylene oxide is fed into the reabsorption stripping system. Absorption water is added from the top of the tower to absorb the ethylene oxide at the bottom. When it passes through the upper packing ceramic rectangular saddle ring, the vaporized ethylene oxide is fully absorbed.
[0059] Step (4): Add high concentrations of ethylene oxide to the refining tower and carbon dioxide stripping tower to further remove residual formaldehyde from the dissolved liquid phase;
[0060] Step (5): The prepared ethylene oxide is passed into a steel cylinder and stored in a cool, ventilated Class A gas cylinder warehouse. The temperature in the gas cylinder warehouse is controlled below 30°C. The warehouse is far away from fire and heat sources, avoids light, and avoids storage with acids, alkalis, alcohols, and food chemicals. Explosion-proof lighting and ventilation facilities are installed in the warehouse.
[0061] Example 3
[0062] Preparation of modified epoxy catalysts
[0063] S1: Preparation of α-alumina support;
[0064] The α-alumina powder was placed in a 0.1 mol / L hydrofluoric acid solution and soaked for 4.5 hours. After filtration, it was rinsed three times with purified water and dried by blowing air for 1.5 hours. This process was repeated three times, and the powder was ground to obtain α-alumina particles with an average particle size of 3-4 mm.
[0065] S2: Impregnation;
[0066] Silver citrate was prepared by adding 1% sodium citrate to boiling silver nitrate under argon protection and stirring continuously for 1 hour.
[0067] Cysteine was dissolved in deionized water to obtain an aqueous solution of cysteine. At 85°C, the prepared silver citrate solution and the aqueous solution of cysteine were mixed at a ratio of 1:1 and reacted for 30 minutes. Then, sodium hydroxide solution was added dropwise to adjust the pH to 7-8, forming a silver amine complex.
[0068] Add 15 parts of tetramethylammonium fluoride to 35 parts of deionized water and stir thoroughly to prepare an aqueous solution of tetramethylammonium fluoride. Add the aqueous solution of tetramethylammonium fluoride to 40 parts of silver ammonia complex, and then add 5 parts of zirconium oxide and 5 parts of yttrium oxide. Stir thoroughly to obtain an impregnation solution.
[0069] Add 2wt% natural rubber binder and modified alumina carrier to the impregnation solution, stir for 40 minutes, mix evenly, and filter to obtain filter residue;
[0070] S3: Drying and activation;
[0071] The filter residue was dried at 200 kPa and 200 °C under argon protection for 1.5 h; after cooling to room temperature, air was introduced into the furnace and activated for 1.5 h to obtain modified epoxy catalyst 3.
[0072] Step (1): Check the biogas tightness of the pipeline, then filter the oxygen and pass it into the mixing station. After the ethylene is desulfurized, it is mixed with oxygen to form a reaction gas with ethylene 30.23% and oxygen 7.05%. The reaction gas is preheated in the gas-to-gas heat exchanger and then passed into the epoxidation reactor containing modified epoxy catalyst 3 at 70°C. At the outlet of the epoxidation reactor, a mixed gas containing ethylene oxide and water are generated to form a dilute solution.
[0073] Step (2): A dilute solution of a mixed gas containing ethylene oxide and water is introduced into the ethylene oxide separation system. The solution is indirectly heated by medium-pressure steam from the bottom heater of the tower, so that the ethylene oxide is extracted from the aqueous solution. Then, the mixed gas containing ethylene oxide is contacted with CO2 removed from the circulating gas of the activated hot potassium alkali process to separate the ethylene oxide from other impurity gases. Finally, the ethylene oxide gas is condensed into a liquid through a condenser.
[0074] Step (3): The liquefied ethylene oxide is fed into the reabsorption stripping system. Absorption water is added from the top of the tower to absorb the ethylene oxide at the bottom. When it passes through the upper packing ceramic rectangular saddle ring, the vaporized ethylene oxide is fully absorbed.
[0075] Step (4): Add high concentrations of ethylene oxide to the refining tower and carbon dioxide stripping tower to further remove residual formaldehyde from the dissolved liquid phase;
[0076] Step (5): The prepared ethylene oxide is passed into a steel cylinder and stored in a cool, ventilated Class A gas cylinder warehouse. The temperature in the gas cylinder warehouse is controlled below 30°C. The warehouse is far away from fire and heat sources, avoids light, and avoids storage with acids, alkalis, alcohols, and food chemicals. Explosion-proof lighting and ventilation facilities are installed in the warehouse.
[0077] In summary, the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any changes, modifications, and evolutions made by those skilled in the art without departing from the scope of the present invention based on the disclosed technical content shall be considered equivalent embodiments of the present invention. Furthermore, any changes, modifications, and evolutions made to the above embodiments based on the essential technology of the present invention shall still fall within the protection scope of the present invention.
Claims
1. A method for preparing ethylene oxide gas, characterized in that, The preparation steps include the following: Step (1): Check the biogas tightness of the pipeline, then filter the oxygen and pass it into the mixing station. After the ethylene is desulfurized, it is mixed with oxygen to form a reaction gas. The reaction gas is preheated in the gas-to-gas heat exchanger and then passed into the epoxidation reactor containing modified epoxy catalyst at 70°C. At the outlet of the epoxidation reactor, a mixed gas containing ethylene oxide and water are generated to form a dilute solution. Step (2): A dilute solution of a mixed gas containing ethylene oxide and water is introduced into the ethylene oxide separation system. The solution is indirectly heated by medium-pressure steam from the bottom heater of the tower, so that the ethylene oxide is extracted from the aqueous solution. Then, the mixed gas containing ethylene oxide is contacted with CO2 removed from the circulating gas of the activated hot potassium alkali process to separate the ethylene oxide from other impurity gases. Finally, the ethylene oxide gas is condensed into a liquid through a condenser. Step (3): The liquefied ethylene oxide is fed into the reabsorption stripping system. Absorption water is added from the top of the tower to absorb the ethylene oxide at the bottom. When passing through the upper packing, the vaporized ethylene oxide is fully absorbed. Step (4): Add high concentrations of ethylene oxide to the refining tower and carbon dioxide stripping tower to further remove residual formaldehyde from the dissolved liquid phase; Step (5): The prepared ethylene oxide is passed into a steel cylinder and stored in a cool, ventilated Class A gas cylinder warehouse.
2. The method for preparing ethylene oxide gas according to claim 1, characterized in that, The reaction control inlet gas concentration in step (1) is: ethylene 30.23%, oxygen 7.05%, and the remainder is stabilized with nitrogen.
3. The method for preparing ethylene oxide gas according to claim 1, characterized in that, The modified epoxy catalyst includes: S1: Preparation of α-alumina support; S2: Under argon protection, add 1-2 wt% of natural rubber binder and modified alumina carrier to the impregnation solution, stir for 30-40 minutes, mix evenly, and filter to obtain filter residue; S3: Dry the filter residue at 150~200Kpa, 150~200℃, and under argon protection for 1~1.5 hours; cool to room temperature, introduce air into the furnace, and activate for 1~1.5 hours to obtain the modified epoxy catalyst.
4. The method for preparing ethylene oxide gas according to claim 3, characterized in that, The preparation steps of the modified α-alumina carrier are as follows: α-alumina powder is placed in 0.1 mol / L hydrofluoric acid solution and soaked for 4-5 hours. After filtration, it is rinsed three times with purified water, dried by blowing air for 1-1.5 hours, and repeated three times. The powder is then ground to obtain α-alumina particles with an average particle size of 3-4 mm.
5. The method for preparing ethylene oxide gas according to claim 3, characterized in that, The impregnation solution comprises the following components by mass: 15-20 parts tetramethylammonium fluoride, 35-45 parts deionized water, 40-45 parts silver ammonia complex, 1-10 parts zirconium oxide, and 1-10 parts yttrium oxide.
6. The method for preparing ethylene oxide gas according to claim 5, characterized in that, The silver amine complex preparation steps are as follows: 1% sodium citrate is added to boiling silver nitrate and stirred continuously for 1 hour to prepare silver citrate; cysteine is dissolved in deionized water to obtain a cysteine aqueous solution; the prepared silver citrate solution and the cysteine aqueous solution are mixed at 1:1 at 80~90℃ and reacted for 30 minutes; then sodium hydroxide solution is added dropwise to adjust the pH to 7~8 to form a silver amine complex.
7. The method for preparing ethylene oxide gas according to claim 1, characterized in that, The upper packing material is a ceramic rectangular saddle ring.
8. The method for preparing ethylene oxide gas according to claim 1, characterized in that, In step (5), the temperature in the gas cylinder storage room is controlled below 30°C. The storage room is kept away from fire and heat sources, avoids light, and avoids storage with acids, alkalis, alcohols, and food chemicals. Explosion-proof lighting and ventilation facilities are installed in the storage room.