Stable gas distribution method in ethylene oxide production process, system and application thereof

Abstract

This invention provides a stable gas distribution method, system, and application in the ethylene oxide production process. The stable gas distribution method of this invention is applicable to the stable distribution of feed gas in the ethylene oxide preparation process. The method includes: introducing the gas to be recycled into a tail gas tank; a portion of the gas in the tail gas tank enters a carbon capture device, and the remaining gas, after being supplemented with ethylene, is pressurized by a compressor and enters a recycling tank; a system stabilizer is added to the recycling tank to reduce the concentration of the main components in the recycling gas and to achieve uniform mixing; then, the gas enters an oxygen mixing station to complete the oxygen distribution operation, obtaining the feed gas. The stable gas distribution method of this invention avoids the problem of directly introducing high-concentration oxygen, ensuring the safe introduction of oxygen and ethylene in the ethylene oxide production process, resulting in good mixing effect of the feed gas and ensuring safety and reliability.

Description

Technical Field

[0001] This invention belongs to the field of ethylene oxide preparation technology, specifically relating to a stable gas distribution method, system, and application in the ethylene oxide production process. Background Technology

[0002] Ethylene oxide is an important chemical intermediate, and the direct oxidation of ethylene is the most commonly used method for its preparation. Ethylene and oxygen are mixed and oxidized under the action of a catalyst. Due to its short process flow, low equipment investment, high catalyst conversion and selectivity, low reaction temperature, and good equipment stability, it is currently the mainstream process for producing ethylene oxide.

[0003] In the process of producing ethylene oxide by oxygen oxidation, high concentrations of oxygen are mixed evenly with ethylene and then reacted at high temperatures. Ethylene is an explosive gas, and its explosion limit in air is very wide, ranging from 2.7% to 36 vol%. Improper operation can easily lead to gas flash explosions.

[0004] Currently, in industrial plants, unreacted ethylene mixtures are compressed and then directly enter an oxygen mixing station. Ethylene and a balance gas (methane) are added before the oxygen mixing station, and then the mixture enters a porous jet-type oxygen mixer. The newly added oxygen mixes with the ethylene recycle gas, rapidly passing through the explosion limit. EDC is then added to the gas exiting the oxygen mixing station. Figure 2 As shown. However, in actual operation, due to the concentrated gas introduction points and short redistribution time, the mixing effect is not very ideal, and explosion accidents have occurred in production facilities in my country.

[0005] There is limited research in this area both domestically and internationally. Patent document CN104084065 discloses a method for mixing ethylene and oxygen in the ethylene oxide production process. This method involves mixing ethylene entering from the main channel and oxygen entering through a radially arranged oxygen distributor in a mixer. The oxygen distributor includes a central main pipe and at least one branch pipe, which are perpendicularly connected. The branch pipes are symmetrically arranged on both sides of the central main pipe and have small holes symmetrically distributed around the central main pipe. The airflow direction in the small holes is consistent with the airflow direction in the main channel, which effectively solves the problem of uniform mixing of ethylene and oxygen.

[0006] Current technology addresses the problem by altering the structure of the oxygen mixer to increase the mixing speed of ethylene and oxygen; however, the results are not very satisfactory. Summary of the Invention

[0007] This invention addresses the problem of unsatisfactory mixing of ethylene and oxygen during ethylene oxide production. It provides a stable gas mixing method, system, and application for ethylene oxide production, achieving safe mixing of oxygen and ethylene during the process, avoiding the direct introduction of high-concentration oxygen, and ensuring good mixing of raw materials and reliable safety.

[0008] To achieve this effect, the technical solution of the present invention is as follows:

[0009] This invention provides a stable gas distribution method applicable to the stable distribution of raw material gas in the preparation of ethylene oxide. The method includes: introducing the gas to be recycled into the tail gas tank; a portion of the gas in the tail gas tank enters a carbon capture device, and the remaining gas, after being supplemented with ethylene, is pressurized by a compressor and enters the recycling gas tank; a system stabilizer is added to the recycling gas tank to reduce the concentration of the main components in the recycling gas and to mix them uniformly; and then the gas enters the oxygen mixing station to complete the oxygen distribution operation, thereby obtaining the raw material gas.

[0010] Preferably, the main component of the circulating gas is ethylene, specifically at a content of 20.0–30.0 mol%, derived from unreacted ethylene in the reaction system, for example: 20.5 mol%, 21.0 mol%, 21.5 mol%, 22.0 mol%, 22.5 mol%, 23 mol%, 23.5 mol%, 24 mol%, 24.5 mol%, 25 mol%, 25.5 mol%, 26 mol%, 26.5 mol%, 27 mol%, 27.5 mol%, 28 mol%, 28.5 mol%, 29 mol%, 29.5 mol%, and 30 mol%.

[0011] Preferably, the flow rate of the circulating gas is 21.00–23.50 Nm³. 3 / h, for example, 23.5Nm 3 / h, 23.4Nm 3 / h, 23.3Nm 3 / h, 23.25Nm 3 / h、23.23Nm 3 / h, 23.21Nm 3 / h, 23.00Nm 3 / h, 22.50Nm 3 / h, 21.19Nm 3 / h, 21.16Nm 3 / h, 21.00Nm 3 / h.

[0012] Preferably, in the stable gas distribution method, the amount of ethylene introduced is controlled according to the ethylene concentration in the circulating gas, and the amount of ethylene introduced is generally 4.8-4.83 Nm³. 3 / h.

[0013] Preferably, in the stable gas distribution method, the amount of oxygen supplied (the amount of oxygen supplied to the oxygen mixing station and / or circulating gas tank) is 1.0–1.3 Nm³. 3 / h.

[0014] Preferably, in the stabilizing gas distribution method, the amount of system stabilizer added is 9.9–10.5 Nm³. 3 / h.

[0015] Preferably, the feed gas obtained by the stable gas distribution method enters the reaction system, where the feed gas is subjected to ethylene oxidation with oxygen to obtain ethylene oxide. The ethylene conversion rate in the reaction system is 8.90-8.96%, and the ethylene oxide selectivity is 85.0-90.0%.

[0016] Preferably, the pressure of the reaction system in the stable gas distribution method is 2.10 ± 0.01 MPa.

[0017] According to an embodiment of the present invention, the feed gas obtained by the stable gas distribution method includes ethylene, oxygen and a system stabilizer.

[0018] According to an embodiment of the present invention, the system stabilizer is selected from at least one of low-carbon saturated alkanes below C2, nitrogen, or an inert gas.

[0019] Preferably, the low-carbon saturated alkane is a C2 or lower component, specifically methane or ethane.

[0020] Preferably, the inert gas is selected from at least one of helium, neon, or argon.

[0021] Preferably, the system stabilizer is introduced when the oxygen content in the reaction system is ≥7.8 mol%.

[0022] According to an embodiment of the present invention, a portion of the gas in the exhaust gas tank enters the carbon capture device to reduce the carbon content in the recirculated gas.

[0023] Preferably, the circulating gas volume entering the carbon capture device is 13.8–14.3 Nm³. 3 / h.

[0024] According to an embodiment of the present invention, a pressure balancing device is further provided between the tail gas tank and the recirculating gas tank to improve system stability and dilute the ethylene concentration in the tail gas tank.

[0025] According to an embodiment of the present invention, the supplemented ethylene is introduced through an ethylene gas distribution system located at the outlet of the tail gas tank and before the recirculating compressor.

[0026] According to an embodiment of the present invention, the system stabilizer may also be partially introduced before the circulating compressor or at the oxygen mixing station.

[0027] Preferably, when the system stabilizer is added before the circulating compressor, the amount added is 0-50% of the total stabilizer amount.

[0028] According to an embodiment of the present invention, the oxygenation operation can be performed in a circulating gas tank and / or an oxygen mixing station.

[0029] Preferably, when the oxygenation operation is carried out in the circulating gas tank and the oxygen mixing station, the amount of oxygen added to the circulating gas tank is 0-40% of the total amount of oxygen added.

[0030] Preferably, the oxygen content in the reaction system is ≤7.0 mol%.

[0031] According to an embodiment of the present invention, a polymerization inhibitor may also be added to the circulating gas.

[0032] Preferably, the content of the polymerization inhibitor in the reaction system is 0.6-0.9 ppm, for example, 0.6 ppm, 0.7 ppm, 0.8 ppm, or 0.9 ppm.

[0033] Preferably, the polymerization inhibitor is selected from EDC.

[0034] Preferably, the polymerization inhibitor is introduced into the oxygen mixing station or the outlet pipeline of the oxygen mixing station.

[0035] The present invention also provides a stable gas distribution system, which is applicable to the above-mentioned stable gas distribution method. The stable gas distribution system includes an exhaust gas tank and a recirculating gas tank, which are connected to the recirculating gas tank via a recirculating compressor. An oxygen mixing station is also provided after the recirculating gas tank.

[0036] According to an embodiment of the present invention, the oxygen mixing station and the tail gas tank are respectively connected to the raw material gas inlet and the circulating gas outlet of the reaction device.

[0037] Preferably, a pressure balancing pipeline is also provided between the circulating gas tank and the exhaust gas tank.

[0038] According to an embodiment of the present invention, the exhaust gas tank is also connected to a carbon capture device.

[0039] Preferably, the carbon capture device is selected from CCUS devices.

[0040] According to an embodiment of the present invention, an ethylene gas distribution system is provided before the circulating compressor.

[0041] Preferably, the ethylene gas distribution system is connected to the circulating compressor via an ethylene gas distribution pipeline.

[0042] Preferably, the total gas flow rate of the ethylene gas distribution system is greater than 4.8 Nm³. 3 / h, for example, 4.8~4.85Nm 3 / h.

[0043] According to an embodiment of the present invention, the exhaust gas tank and the recirculating gas tank are respectively connected to the stabilizer supply system.

[0044] Preferably, the total gas flow rate of the stabilizer supply system is greater than 10 Nm³. 3 / h, for example, 10~10.5Nm 3 / h.

[0045] According to an embodiment of the present invention, the circulating gas tank and the oxygen mixing station are respectively connected to the oxygen supply system.

[0046] Preferably, the total gas flow rate of the oxygen supply system is greater than 1 Nm³. 3 / h, for example, 1~1.3Nm 3 / h.

[0047] According to an embodiment of the present invention, the oxygen mixing station and the outlet pipeline of the oxygen mixing station are respectively connected to the polymerization inhibitor.

[0048] The present invention also provides the application of the above system in the production of ethylene oxide.

[0049] The present invention also provides an ethylene oxide production apparatus, the apparatus comprising the above-mentioned stable gas distribution system.

[0050] According to an embodiment of the present invention, the production apparatus further includes a reactor, a heat exchanger, an absorption tower, a gas-liquid separator, and a dryer connected in sequence. The reactor is provided with a raw material gas inlet, and the dryer is provided with a circulating gas outlet. The oxygen mixing station and the tail gas tank are respectively connected to the raw material gas inlet and the circulating gas outlet.

[0051] Preferably, the reactor is a single-tube reactor.

[0052] Beneficial effects

[0053] This invention, by setting up a tail gas tank and a circulating gas tank, is more conducive to the uniform mixing of ethylene and oxygen feedstock gases, and achieves stable gas distribution in the reaction system.

[0054] The present invention sets up a pressure balancing pipeline between the exhaust gas tank and the recirculation gas tank, which improves system stability on the one hand, and dilutes the ethylene concentration in the exhaust gas tank and reduces the carbon content in the recirculation gas on the other hand.

[0055] The present invention further reduces the carbon content in the recirculated gas by connecting the exhaust gas tank to a carbon capture device.

[0056] This invention provides a stable gas distribution system in an ethylene oxide production unit, ensuring smooth operation of the production system during the ethylene oxide production process.

[0057] The stable gas mixing method of the present invention avoids the problem of directly introducing high-concentration oxygen, so as to safely introduce oxygen and ethylene in the ethylene oxide production process, with good mixing effect of raw material gas, and is safe and reliable. Attached Figure Description

[0058] Figure 1 This is a process diagram of the ethylene oxide production process of the present invention; wherein:

[0059] 1—Reactor; 2—Heat exchanger; 3—Absorber; 4—Circulating compressor; 5—Dryer; 6—Liquid storage tank; 7—Circulating gas tank; 8—Gas-liquid separator; 9—Oxygen mixing station; 10—Tail gas tank; 11—Pressure balancing pipeline;

[0060] a—Absorbent; b—To CCUS; c—Ethylene / Ethylene + Nitrogen; d—Nitrogen / Oxygen + Nitrogen; e—Oxygen + EDC / Oxygen;

[0061] Figure 2 This is a diagram of a traditional ethylene oxide production process. In the diagram:

[0062] 1—Reactor; 2—Heat exchanger; 3—Absorber; 4—Circulating compressor; 9—Oxygen mixing station; 12—Cooler;

[0063] a—Absorbent; b—To CCUS; f—Rich circulating water; g—Methane; h—Ethylene; i—Oxygen; j—EDC. Detailed Implementation

[0064] [Stable Gas Distribution Method]

[0065] This invention provides a stable gas distribution method applicable to the stable distribution of raw material gas in the preparation of ethylene oxide. The method includes: introducing the gas to be recycled into the tail gas tank; a portion of the gas in the tail gas tank enters a carbon capture device, and the remaining gas, after being supplemented with ethylene, is pressurized by a compressor and enters the recycling gas tank; a system stabilizer is added to the recycling gas tank to reduce the concentration of the main components in the recycling gas and to mix them uniformly; and then the gas enters the oxygen mixing station to complete the oxygen distribution operation, thereby obtaining the raw material gas.

[0066] In one specific embodiment, the main component of the circulating gas is ethylene, specifically at a content of 20.0–30.0 mol%, derived from unreacted ethylene in the reaction system, for example: 20.5 mol%, 21.0 mol%, 21.5 mol%, 22.0 mol%, 22.5 mol%, 23 mol%, 23.5 mol%, 24 mol%, 24.5 mol%, 25 mol%, 25.5 mol%, 26 mol%, 26.5 mol%, 27 mol%, 27.5 mol%, 28 mol%, 28.5 mol%, 29 mol%, 29.5 mol%, and 30 mol%.

[0067] In one specific embodiment, the flow rate of the circulating gas is 21.00–23.50 Nm³. 3 / h, for example, 23.5Nm 3 / h, 23.4Nm 3 / h, 23.3Nm 3 / h, 23.25Nm 3 / h、23.23Nm 3 / h, 23.21Nm 3 / h, 23.00Nm 3 / h, 22.50Nm 3 / h, 21.19Nm 3 / h, 21.16Nm 3 / h, 21.00Nm 3 / h.

[0068] In one specific embodiment, the amount of ethylene introduced in the stabilized gas distribution method is generally 4.8-4.83 Nm³. 3 / h.

[0069] In one specific embodiment, the amount of oxygen supplied in the stable gas distribution method (the amount of oxygen supplied to the oxygen mixing station and / or circulating gas tank) is 1.0–1.3 Nm³. 3 / h.

[0070] In one specific embodiment, the amount of system stabilizer added in the stabilizing gas distribution method is 9.9–10.5 Nm³. 3 / h.

[0071] In one specific embodiment, the feed gas obtained from the stable gas distribution method enters the reaction system, where the feed gas is subjected to ethylene oxidation with oxygen to obtain ethylene oxide. The ethylene conversion rate in the reaction system is 8.90–8.96%, and the ethylene oxide selectivity is 85.0–90.0%.

[0072] In one specific embodiment, the pressure of the reaction system in the stable gas distribution method is 2.10 ± 0.01 MPa.

[0073] According to an embodiment of the present invention, the feed gas obtained by the stable gas distribution method includes ethylene, oxygen and a system stabilizer.

[0074] According to an embodiment of the present invention, the system stabilizer is selected from at least one of low-carbon saturated alkanes below C2, nitrogen, or an inert gas.

[0075] In one specific embodiment, the low-carbon saturated alkane is a C2 or lower component, specifically methane or ethane.

[0076] In one specific embodiment, the inert gas is selected from at least one of helium, neon, or argon.

[0077] In one specific embodiment, the system stabilizer is incorporated under the condition that the oxygen content in the reaction system is ≥7.8 mol%.

[0078] According to an embodiment of the present invention, a portion of the gas in the exhaust gas tank enters the carbon capture device to reduce the carbon content in the recirculated gas.

[0079] In one specific design, the recirculated gas volume entering the carbon capture device is 13.8–14.3 Nm³. 3 / h.

[0080] According to an embodiment of the present invention, a pressure balancing device is further provided between the tail gas tank and the recirculating gas tank to improve system stability and dilute the ethylene concentration in the tail gas tank.

[0081] According to an embodiment of the present invention, the supplemented ethylene is introduced through an ethylene gas distribution system located at the outlet of the tail gas tank and before the recirculating compressor.

[0082] According to an embodiment of the present invention, the system stabilizer may also be partially introduced before the circulating compressor or at the oxygen mixing station.

[0083] Generally, when the oxygen content in the reaction system rises too quickly, the system stabilizer is added before the compressor; when the oxygen content in the reaction system rises relatively steadily, the system stabilizer is added at the oxygen mixing station.

[0084] In one specific embodiment, when the system stabilizer is added before the circulating compressor, the amount added is 0-50% of the total stabilizer amount.

[0085] According to an embodiment of the present invention, the oxygenation operation can be performed in a circulating gas tank and / or an oxygen mixing station.

[0086] In one specific embodiment, when the oxygenation operation is carried out in the circulating gas tank and the oxygen mixing station, the amount of oxygen added to the circulating gas tank is 0-40% of the total amount of oxygen added.

[0087] In one specific scheme, the condition for oxygen introduction is that the oxygen content in the system is ≤7.0 mol%.

[0088] According to an embodiment of the present invention, a polymerization inhibitor may also be added to the circulating gas.

[0089] In one specific embodiment, the polymerization inhibitor content in the system is 0.6-0.9 ppm, for example, 0.6 ppm, 0.7 ppm, 0.8 ppm, or 0.9 ppm.

[0090] In one specific embodiment, the polymerization inhibitor is selected from EDC.

[0091] In one specific embodiment, the polymerization inhibitor is introduced into the oxygen mixing station or the outlet pipeline of the oxygen mixing station.

[0092] [Stable Gas Distribution System]

[0093] The present invention also provides a stable gas distribution system, which is applicable to the above-mentioned stable gas distribution method. The stable gas distribution system includes an exhaust gas tank and a recirculating gas tank, which are connected to the recirculating gas tank via a recirculating compressor. An oxygen mixing station is also provided after the recirculating gas tank.

[0094] In one specific embodiment, the oxygen mixing station and the tail gas tank are respectively connected to the feed gas inlet and the circulating gas outlet of the ethylene oxide production unit.

[0095] In one specific embodiment, a pressure balancing pipeline is also installed between the circulating gas tank and the exhaust gas tank.

[0096] The present invention improves system stability by installing a pressure balancing pipeline between the circulating gas tank and the tail gas tank, and also dilutes the ethylene concentration in the tail gas tank and reduces the carbon content in the circulating gas.

[0097] According to an embodiment of the present invention, the exhaust gas tank is also connected to a carbon capture device.

[0098] In one specific embodiment, the carbon capture device is selected from CCUS devices.

[0099] According to an embodiment of the present invention, an ethylene gas distribution system is provided before the circulating compressor.

[0100] In one specific embodiment, the ethylene gas distribution system is connected to the circulating compressor via an ethylene gas distribution pipeline.

[0101] In one specific embodiment, the ethylene gas distribution system is selected from commonly used gas distribution systems in this technical field, as long as it can provide the required ethylene.

[0102] In one specific embodiment, the total gas flow rate of the ethylene gas distribution system is greater than 4.8 Nm³. 3 / h, for example, 4.8~4.85Nm 3 / h.

[0103] According to an embodiment of the present invention, the exhaust gas tank and the recirculating gas tank are respectively connected to the stabilizer supply system.

[0104] In one specific embodiment, the system stabilizer supply system is selected from commonly used supply systems in this technical field, as long as it can provide the required system stabilizer.

[0105] In one specific embodiment, the total gas flow rate of the stabilizer supply system is greater than 10 Nm³. 3 / h, for example, 10~10.5Nm 3 / h.

[0106] According to an embodiment of the present invention, the circulating gas tank and the oxygen mixing station are respectively connected to the oxygen supply system.

[0107] In one specific embodiment, the oxygen supply system is selected from commonly used oxygen supply systems in this technical field, as long as it can provide the required oxygen.

[0108] In one specific embodiment, the total gas flow rate of the oxygen supply system is greater than 1 Nm³. 3 / h, for example, 1~1.3Nm 3 / h.

[0109] According to an embodiment of the present invention, the oxygen mixing station and the outlet pipeline of the oxygen mixing station are respectively connected to the polymerization inhibitor.

[0110] The present invention incorporates an exhaust gas tank and a recirculating gas tank in the stable gas distribution system, which is more conducive to the uniform mixing of gases.

[0111] [application]

[0112] The present invention also provides the application of the above-mentioned stable gas distribution system in the production of ethylene oxide.

[0113] Ethylene oxide production unit

[0114] The present invention also provides an ethylene oxide production apparatus, the apparatus comprising the above-mentioned stable gas distribution system.

[0115] According to an embodiment of the present invention, the production apparatus further includes a reactor, a heat exchanger, an absorption tower, a gas-liquid separator, and a dryer arranged in sequence. The reactor is provided with a raw material gas inlet, and the dryer is provided with a circulating gas outlet. The circulating gas outlet is connected to the tail gas tank of the stable gas distribution system, and the outlet of the oxygen mixing station of the stable gas distribution system is connected to the raw material gas inlet on the reactor.

[0116] In one specific embodiment, the gas-liquid separator is also connected to a liquid storage tank.

[0117] In one specific embodiment, the reactor is a single-tube reactor.

[0118] In one specific embodiment, the catalyst loading in the reactor is 4.80–4.90 L, preferably 4.81–4.85 L.

[0119] In one specific embodiment, the reaction space velocity in the reactor is 4800–4900 h⁻¹. -1 Preferably 4800-4850h -1 .

[0120] In this invention, when the production device is running, ethylene oxide is first prepared in a reactor and then separated by a gas-liquid separator to obtain circulating gas. After being dried by a dryer, the circulating gas enters the above-mentioned stable gas distribution system to obtain raw material gas, which is then returned to the reactor.

[0121] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0122] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0123] like Figure 1 As shown, the ethylene oxide production apparatus of the present invention includes a reactor 1, a heat exchanger 2, an absorption tower 3, a gas-liquid separator 8, and a dryer 10 connected in sequence. The gas-liquid separator 8 is connected to a storage tank 6 (the liquid separated by the gas-liquid separator 8 is discharged into the storage tank 6, and the gas enters the dryer 10). The absorption tower 3 has an inlet for the absorbent liquid a (located at the top of the absorption tower 3).

[0124] The production unit also includes a stable gas distribution system, which comprises a tail gas tank 7, a circulating compressor 4, a circulating gas tank 9, and an oxygen mixing station 5 connected in sequence. The circulating gas outlet of the dryer 10 is connected to the tail gas tank 7 (i.e., the circulating gas dried by the dryer 10 is discharged from the circulating gas outlet and enters the tail gas tank 7). The outlet of the oxygen mixing station 5 is connected to the feed gas inlet of the reactor 1 (i.e., the feed gas discharged from the oxygen mixing station 5 is introduced into the reactor 1 through the feed gas inlet). Additionally, the tail gas tank 7 and the circulating gas tank 9 are connected via a pressure balancing pipeline 11. Furthermore, the tail gas tank 7 is also connected to a CCUS (Combined Controlled Gas System). An ethylene / ethylene + nitrogen c inlet is provided on the connecting pipeline between the tail gas tank 7 and the circulating compressor 4. A nitrogen / oxygen + nitrogen d inlet is provided on the circulating gas tank 9. An oxygen + EDC / oxygen e inlet is provided on the oxygen mixing station 5.

[0125] Example 1

[0126] In this embodiment, a single-tube reactor is used, with a catalyst loading of 4.84 L and a reaction space velocity of 4800 h⁻¹. -1 The ethylene recycle gas after the reaction is 21.23 Nm³. 3 / h, ethylene recycle gas (after being discharged from the recycle gas outlet of dryer 10) enters tail gas tank 7, of which 14Nm 3 The reaction tail gas is routed to the CCUS system via a branch line, while the remaining ethylene recycle gas is distributed to the ethylene system via the tail gas tank outlet pipeline at a flow rate of 4.8 Nm³. 3 / h; then it enters the circulating gas tank 9 via the circulating compressor 4, with a nitrogen volume of 10Nm³. 3 / h; The gas from the outlet of circulating gas tank 9 enters oxygen mixing station 5, where a stable mixture of oxygen and EDC is introduced at a flow rate of 1.2 Nm³. 3 The reaction system has an EDC content of 0.9 ppm and an oxygen content of 7.5 mol% per hour. The feed gas, after being processed by the stable gas distribution system, can be returned to reactor 1. The entire reaction system operates smoothly at a pressure of 2.10 ± 0.01 MPa. Using a self-made Ag catalyst, the ethylene conversion rate is 8.90%, and the ethylene oxide selectivity is 86.0%.

[0127] Example 2

[0128] In this embodiment, a single-tube reactor is used, with a catalyst loading of 4.85 L and a reaction space velocity of 4850 h⁻¹. -1 The ethylene recycle gas after the reaction is 21.19 Nm³. 3 / h, ethylene recycle gas (after being discharged from the recycle gas outlet of dryer 10) enters the tail gas tank, of which 14.3 Nm 3 The / h reaction tail gas goes to the CCUS system via a branch line, and the remaining ethylene recycle gas is mixed with a mixture of ethylene and nitrogen through the tail gas tank outlet pipeline. The flow rates of the mixture are: ethylene 4.83 Nm³. 3 / h, nitrogen 4.0Nm 3 / h; then it enters the circulating gas tank 9 via the circulating compressor 4, with a nitrogen volume of 6.5 Nm³. 3 / h; The gas from the outlet of circulating gas tank 9 enters oxygen mixing station 5, where a stable mixture of oxygen and EDC gas is introduced at a flow rate of 1.3 Nm³. 3 The reaction system has an EDC content of 0.6 ppm and an oxygen content of 7.7 mol% per hour. The feed gas, after being processed by the stable gas distribution system, can be returned to reactor 1. The entire reaction system operates smoothly at a pressure of 2.10 ± 0.01 MPa. It uses a self-made Ag catalyst, achieving an ethylene conversion rate of 8.92% and an ethylene oxide selectivity of 87.6%.

[0129] Example 3

[0130] In this embodiment, a single-tube reactor is used, with a catalyst loading of 4.82 L and a reaction space velocity of 4847 h⁻¹. -1 The ethylene recycle gas after the reaction is 21.16 Nm³. 3 / h, ethylene recirculation gas (after being discharged from the recirculation gas outlet of dryer 10) enters the tail gas tank, of which 13.9 Nm 3 The reaction tail gas is routed to the CCUS system via a branch line, while the remaining ethylene recycle gas is distributed to the ethylene system via the tail gas tank outlet pipeline at a flow rate of 4.80 Nm³. 3 / h; then it enters the circulating gas tank 9 via the circulating compressor 4, with a nitrogen volume of 6.4 Nm³. 3 / h; The gas from the outlet of circulating gas tank 9 enters oxygen mixing station 5, where a stable mixture of oxygen and nitrogen is introduced, with a total flow rate of 4.9 Nm³. 3 The oxygen content is 26.5 vol%, and nitrogen and EDC mixture is introduced at outlet 5 of the oxygen mixing station at a flow rate of 1.2 Nm³ / h. 3 The reaction system has an EDC content of 0.7 ppm and an oxygen content of 7.4 mol% per hour. The feed gas, after being processed by the stable gas distribution system, can be returned to reactor 1. The entire reaction system operates smoothly at a pressure of 2.10 ± 0.01 MPa. It uses a self-made Ag catalyst, achieving an ethylene conversion rate of 8.96% and an ethylene oxide selectivity of 85.5%.

[0131] Example 4

[0132] In this embodiment, a single-tube reactor is used, with a catalyst loading of 4.84 L and a reaction space velocity of 4823 h⁻¹. -1 The ethylene recycle gas after the reaction is 21.19 Nm³. 3 / h, ethylene recirculation gas (after being discharged from the recirculation gas outlet of dryer 10) enters the tail gas tank, of which 13.8 Nm 3 The reaction tail gas is routed to the CCUS system via a branch line, while the remaining ethylene recycle gas is distributed to the ethylene system via the tail gas tank outlet pipeline at a flow rate of 4.82 Nm³. 3 / h; then it enters the circulating gas tank 9 via the circulating compressor 4, with a methane content of 9.95 Nm³. 3 / h; The gas from the outlet of circulating gas tank 9 enters oxygen mixing station 5, where a stable mixture of oxygen and EDC gas is introduced, with a flow rate of 1.18 Nm³. 3 The reaction system has an EDC content of 0.8 ppm and an oxygen content of 7.5 mol% per hour. The feed gas, after being processed by the stable gas distribution system, can be returned to reactor 1. The entire reaction system operates smoothly at a pressure of 2.10 ± 0.01 MPa. It uses a self-made Ag catalyst, achieving an ethylene conversion rate of 8.91% and an ethylene oxide selectivity of 88.4%.

[0133] The exemplary embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for stabilizing gas distribution, the method being applicable to the stabilizing gas distribution of feedstock in the preparation of ethylene oxide, characterized in that, The method includes: introducing the gas to be recycled into the tail gas tank; a portion of the gas in the tail gas tank enters the carbon capture device, and the remaining gas, after being supplemented with ethylene, is pressurized by the recycling compressor and enters the recycling gas tank; a system stabilizer is added to the recycling gas tank to reduce the concentration of the main components in the recycling gas and to mix them evenly; and then the gas enters the oxygen mixing station to complete the oxygen mixing operation to obtain the raw material gas. A pressure balancing pipeline is also installed between the circulating gas tank and the exhaust gas tank.

2. The stable gas distribution method according to claim 1, characterized in that, The main component of the circulating gas is ethylene, with a content of 20.0~30.0 mol%, which comes from unreacted ethylene in the reaction system; The flow rate of the recirculated gas is 21.00~23.50 Nm³. 3 / h; In the aforementioned stable gas distribution method, the amount of ethylene introduced is controlled according to the ethylene concentration in the circulating gas, and the amount of ethylene introduced is 4.8-4.83 Nm³ / h; In the aforementioned stable gas mixing method, the amount of oxygen introduced is 1.0~1.3 Nm³. 3 / h; In the aforementioned stable gas distribution method, the amount of system stabilizer added is 9.9~10.5 Nm. 3 / h.

3. The stable gas distribution method according to claim 1, characterized in that, The system pressure in the stabilized gas distribution method is 2.10 ± 0.01 MPa; The feed gas obtained by the stabilized gas distribution method includes ethylene, oxygen, and a system stabilizer; The system stabilizer is selected from at least one of low-carbon saturated alkanes, nitrogen, or inert gases; The system stabilizer is introduced when the oxygen content in the system is ≥7.8 mol%; Some of the gas in the exhaust gas tank enters the carbon capture device to reduce the carbon content in the recirculated gas. The recirculated gas volume entering the carbon capture device is 13.8~14.3 Nm³. 3 / h; A pressure balancing device is also installed between the tail gas tank and the recirculating gas tank to improve system stability and dilute the ethylene concentration in the tail gas tank. The supplemental ethylene is introduced through an ethylene gas distribution system located at the tail gas tank outlet and before the recirculation compressor.

4. The stable gas distribution method according to claim 3, characterized in that, The low-carbon saturated alkane is methane or ethane; The inert gas is selected from at least one of helium, neon, or argon.

5. The stable gas distribution method according to claim 1, characterized in that, The system stabilizer is also partially added before the circulating compressor or the oxygen mixing station; When the system stabilizer is added before the circulating compressor, the amount added is 0-50% of the total stabilizer amount.

6. The stable gas distribution method according to claim 1, characterized in that, Oxygenation is performed in a circulating gas tank and / or an oxygen mixing station; When the oxygenation operation is carried out in the circulating gas tank and the oxygen mixing station, the amount of oxygen added to the circulating gas tank is 0-40% of the total amount of oxygen added. The condition for introducing oxygen is that the oxygen content in the reaction system is <7.0 mol.

7. The stable gas distribution method according to claim 1, characterized in that, A polymerization inhibitor is also added to the circulating gas; The polymerization inhibitor content in the reaction system is 0.6-0.9 ppm; The polymerization inhibitor is introduced into the oxygen mixing station or the outlet pipeline of the oxygen mixing station.

8. The stable gas distribution method according to claim 1, characterized in that, The polymerization inhibitor content in the reaction system is 0.6 ppm, 0.7 ppm, 0.8 ppm, and 0.9 ppm; The polymerization inhibitor is selected from EDC.

9. A stable gas distribution system, characterized in that, The stable gas distribution system is applicable to the stable gas distribution method according to any one of claims 1-8. The stable gas distribution system includes an exhaust gas tank and a recirculating gas tank, wherein the exhaust gas tank and the recirculating gas tank are connected through a recirculating compressor; and an oxygen mixing station is also provided after the recirculating gas tank.

10. The stable gas distribution system according to claim 9, characterized in that, The exhaust gas tank is also connected to a carbon capture device; An ethylene gas distribution system is installed before the circulating compressor; The ethylene gas distribution system is connected to the circulating compressor via an ethylene gas distribution pipeline; The total gas flow rate of the ethylene distribution system is greater than 4.8 Nm³. 3 / h; The tail gas tank and the recirculation gas tank are respectively connected to the stabilizer supply system; The total gas flow rate of the stabilizer supply system is greater than 10 Nm³. 3 / h; The circulating gas tank and oxygen mixing station are respectively connected to the oxygen supply system; The total gas flow rate of the oxygen supply system is greater than 1 Nm³. 3 / h; The oxygen mixing station and its outlet pipeline are respectively connected to the polymerization inhibitor.

11. The stable gas distribution system according to claim 10, characterized in that, The carbon capture device is selected from CCUS devices; The total gas flow rate of the ethylene gas distribution system is 4.8~4.85 Nm³. 3 / h; The total gas flow rate of the stabilizer supply system is 10~10.5 Nm³. 3 / h; The total gas flow rate of the oxygen supply system is 1~1.3 Nm³. 3 / h.

12. The application of the stable gas distribution system according to any one of claims 9-11 in the production of ethylene oxide.

13. An ethylene oxide production apparatus, characterized in that, The ethylene oxide production unit includes the stable gas distribution system as described in any one of claims 9-11; The ethylene oxide production unit also includes a reactor, a heat exchanger, an absorption tower, a gas-liquid separator, and a dryer connected in sequence. The reactor is provided with a raw material gas inlet, and the dryer is provided with a circulating gas outlet. The oxygen mixing station and the tail gas tank are respectively connected to the raw material gas inlet and the circulating gas outlet. The reactor is a single-tube reactor.

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