An ethane-stabilized side draw ethylene-ethane oxide combination system and method

Abstract

This invention belongs to the fields of intrinsically safe chemical processes and chemical process economics, and provides an ethane-stabilized side-stream ethylene-ethylene oxide combined system and method: A mixed feedstock of ethylene and ethane enters an ethylene-ethane distillation column with a side-stream product for separation. Ethylene is collected from the top of the column, and ethane is collected from the bottom. The molar ratio of the ethylene and ethane mixture collected from the sidestream is adjusted according to different operating conditions during start-up and stable operation. The mixture is then mixed with pure oxygen and reacted in an ethylene direct oxidation reactor. The generated gas is absorbed by an ethylene oxide absorption column. The gas from the top of the column serves as the reaction recirculation gas, mixing with the ethylene-ethane mixture and pure oxygen for a cyclic reaction. The ethylene oxide from the bottom of the column is purified by a stripping column and a refining column to obtain the product ethylene oxide. This invention changes the ethylene-ethane separation method, replacing precise separation with side-stream separation. While meeting the requirements of subsequent processes and reaction safety, it reduces significant energy loss and improves overall economic efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of intrinsically safe chemical process, and particularly relates to an ethane stabilizing side line ethylene-ethylene oxide combined system and method. BACKGROUND

[0002] Ethylene oxide (EO) is an important organic chemical raw material, and domestic produced ethylene oxide is mainly used for producing ethylene glycol. Downstream products of ethylene oxide are very rich, and main uses thereof include sterilization and disinfection, acid resistance reaction, rocket and jet fuel, and chain initiator of chain reaction polymerization, etc. At present, there are two methods for industrial production of ethylene oxide, i.e. chloroethanol method and ethylene direct oxidation method. The ethylene direct oxidation method is more advanced, is suitable for large-scale production, and has large product quantity and high quality (product purity can be as high as 99.99%), and can well meet the demand of downstream products. Therefore, the ethylene direct oxidation method has become the main method for current industrial production of ethylene oxide. Since ethylene has a very wide explosion range (2.75% to 28.6%) in oxygen, therefore, in addition to operation conditions, catalyst and reaction equipment, selection of stabilizing gas is also an important technical index affecting reaction quality.

[0003] The selection of the stabilizing gas involves safety, stability and heat removal capacity, etc. Methane is currently used as the stabilizing gas in the direct oxidation of ethylene to ethylene oxide in industry. Methane stabilization has the advantages of good stability and high safety, but it still has some deficiencies compared with ethane stabilization. Ethane is a common chemical product in process production, which can be used as a stabilizing gas in the direct oxidation of ethylene. The use of ethane as a stabilizing gas has many advantages. First, in the process of direct oxidation of ethylene to ethylene oxide, ethylene and ethylene oxide are both explosive hazardous materials. As a stabilizing gas, ethane does not participate in the reaction, but can effectively dilute the concentration of explosive materials and reduce the explosion range, thereby avoiding the occurrence of dangerous phenomena such as overheat explosion and greatly improving the safety of the reaction. Second, ethane stabilization can significantly improve the stability of the system. For example, the maximum recommended concentration of oxygen and the concentration of ethylene in the ethylene-oxygen-methane ternary mixture at 2.32 MPa and 250°C are as follows: ethylene concentration 8.0% (mol), oxygen concentration 11.8% (mol); ethylene concentration 28.0% (mol), oxygen concentration 10.55% (mol). However, the maximum recommended concentration of oxygen and the concentration of ethylene in the ethylene-oxygen-ethane ternary mixture at 2.32 MPa and 250°C are as follows: ethylene concentration 8.0% (mol), oxygen concentration 14.55% (mol); ethylene concentration 28.0% (mol), oxygen concentration 13.0% (mol). Third, the thermal stability of ethane is better than that of methane. For example, when the molar flow rate of the reaction raw material entering the reactor is the same, and the reaction temperature reaches 265°C under the reaction conditions of 200°C and 2.1 MPa, the inlet oxygen content is 7.87% (mol) when methane is used as the stabilizing gas, while the inlet oxygen concentration can reach 11.64% (mol) when ethane is used as the stabilizing gas.

[0004] When ethane is used as the stabilizing gas, the feed entering the direct oxidation reactor of ethylene becomes a mixture mainly composed of ethylene, ethane and oxygen. Since the purity of ethylene is required to be not less than 99.95% (vol) when methane is used as the stabilizing gas, high-purity separation of ethylene and ethane in the process will result in high energy consumption. However, when ethane is used as the stabilizing gas, the high-purity ethylene product at the top of the column, the high-purity ethane product at the bottom of the column and the ethane and ethylene mixture at the side line can be used for recovery in a certain proportion (which will change with the start-up state and steady-state operation). Under the premise of the same feed stream, the use of side-line separation instead of precise separation will save a large amount of energy, ensure high safety, save a large amount of energy and improve the overall economy.

[0005] CN 110201487A discloses a method for purifying and recycling high-purity and high-yield methane stabilizing gas in the ethylene method for preparing ethylene oxide, which introduces a new process method and improves the utilization rate of methane in the process, but the process is relatively complex and the energy consumption is high, the use of methane stabilizing gas leads to a low maximum oxygen content allowed in the reactor, the reactor efficiency is low, and the industrial application is limited to a certain extent. SUMMARY

[0006] The purpose of the present application is to provide an ethane stabilizing side-line ethylene-ethylene oxide combined system and method, which reasonably selects a new stabilizing gas, uses the molar ratio of ethylene and oxygen with high economic efficiency under safe conditions, reduces energy consumption, improves the separation method of the ethylene-ethane rectifying column before the ethylene direct oxidation reactor, and selects appropriate reaction temperature, reaction pressure and space velocity, so that the reaction performance of the ethylene direct oxidation method can reach the level of industrialization.

[0007] To achieve the above purpose, the present application adopts the following technical scheme: an ethane stabilizing side-line ethylene-ethylene oxide combined system, which comprises an ethylene-ethane separation system, an ethylene direct oxidation system for generating ethylene oxide and an ethylene oxide refining system; the ethylene-ethane separation system comprises an ethylene-ethane rectifying column T1 with a side-line product; the ethylene direct oxidation system for generating ethylene oxide comprises a mixer MIX, a drying device V1, a carbon dioxide removal device V2, an ethylene direct oxidation reactor R1, an ethylene oxide absorption column T2, a plurality of heat exchange devices and a compressor C1; the ethylene oxide refining system comprises an ethylene oxide stripping column T3 and an ethylene oxide refining column T4.

[0008] The side-line product of the ethylene-ethane rectifying column T1 and pure oxygen are respectively heat exchanged in the respective heat exchange devices, mixed in the mixer MIX, and then the obtained mixture is introduced into the ethylene direct oxidation reactor R1 through the drying device V1, and then heat exchanged in the third heat exchange device H3, and then introduced into the ethylene oxide absorption column T2; the overhead product of the ethylene oxide absorption column T2 is introduced into the carbon dioxide removal device V2, and then circulated back to the mixer MIX through the compressor C1 and the fourth heat exchange device H4; the bottom product of the ethylene oxide absorption column T2 is introduced into the ethylene oxide stripping column T3, and the overhead of the ethylene oxide stripping column T3 is introduced into the ethylene oxide refining column T4.

[0009] An ethane-stabilized side-line ethylene-ethylene oxide combined method, ethylene and ethane mixed raw materials enter an ethylene-ethane rectifying column T1 with side-line product tapping to be separated; ethylene-ethane rectifying column T1 top tapping ethylene product (can reach more than 99.95wt%), bottom tapping ethane product (can reach more than 99.95wt%), ethylene-ethane rectifying column T1 side-line product tapping is different molar ratio, side-line tapping ethylene and ethane form a mixture, after first heat exchange device H1 heat exchange, get heat exchanged ethylene and ethane mixture 1; pure oxygen gas passes through second heat exchange device H2 heat exchange to get heat exchanged oxygen 2; heat exchanged ethylene and ethane mixture 1 and heat exchanged oxygen 2 are mixed in mixer MIX according to a certain proportion to get ethylene, ethane and oxygen mixture 3; after drying device V1 drying and dehydrating, get reactant 4; reactant 4 is input into ethylene direct oxidation reactor R1 to react, wherein ethane acts as stabilizing gas, reaction heat generated by reaction is partly taken away by reactor external heat removal agent, after reaction, product 5 passes through third heat exchange device H3 to get feed gas 6; feed gas 6 is input into ethylene oxide absorption column T2 bottom to wash away ethylene oxide; after carbon dioxide removal device V2 removes carbon dioxide, ethylene oxide absorption column T2 top gas mixture 7 is compressed by compressor C1 to increase temperature and pressure to act as reaction circulating gas 9, after fourth heat exchange device H4 heat exchange, become reaction circulating gas 10 re-entering the mixer, return to mixer MIX; ethylene and ethane consumed in ethylene-ethane rectifying column T1 side-line stream supplement the overall process flow; ethylene oxide 8 washed out by ethylene oxide absorption column T2 is input into ethylene oxide stripping column T3, liquid mixture 12 is tapped from ethylene oxide stripping column T3 bottom; ethylene oxide stripping column top gas 11 is input into ethylene oxide refining column T4, gas impurities 13 are tapped from ethylene oxide refining column T4 top, ethylene oxide product 14 is obtained from ethylene oxide refining column T4 bottom.

[0010] The molar ratio of ethane in the ethylene and ethane mixed raw materials is 1% to 99%, and the rest is ethylene.

[0011] The molar ratio of ethane in the ethylene and ethane mixture tapped from the ethylene-ethane rectifying column T1 is 0% to 80%.

[0012] The molar ratio of ethylene in the reactant 4 input into the ethylene direct oxidation reactor R1 is 5% to 50%, and the rest is oxygen and stabilizing gas; after ethylene, oxygen and stabilizing gas are mixed, there is no explosion danger; the reaction temperature in the ethylene direct oxidation reactor R1 is 150 to 250℃, the reaction pressure is 1.5Mpa to 2.5Mpa, and the space velocity is 10 to 50000h -1 .

[0013] The ethylene direct oxidation reactor R1 is a tubular fixed bed reactor, and the catalyst therein is a silver catalyst.

[0014] The molar concentration of the inhibitor dichloroethane EDC inhibitor in the ethylene direct oxidation reactor R1 is 0-3.5E-04%.

[0015] The separation mode of the ethylene ethane rectifying column T1 is precision separation.

[0016] The present application has the beneficial effect that the present application changes the ethylene ethane separation mode, changes the precision separation to side-line separation, reduces a large amount of energy loss under the premise of meeting the subsequent process requirements, reduces the operating cost of the equipment, and improves the economy of the process. The present application uses the economic and environmentally friendly ethylene direct oxidation method to synthesize ethylene oxide. Under the premise of ensuring safety, the present application increases the maximum oxygen concentration allowed in the reactor, increases the overall conversion rate of the reaction, improves the economy of the process, and reaches the level suitable for process production. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a schematic flow chart of the ethane-stabilized side-line ethylene-ethylene oxide combined system and method;

[0018] Figure 2 It is the separation mode of the ethylene ethane rectifying column;

[0019] Figure 3 It is the relationship between the maximum recommended concentration of oxygen and the ethylene concentration of the ethylene-oxygen-stabilizing gas ternary mixture at 2.32 MPa and 250 DEG C.

[0020] In the figure, T1 is an ethylene ethane rectifying column; T2 is an ethylene oxide absorption column; T3 is an ethylene oxide stripping column; T4 is an ethylene oxide refining column; H1 is a first heat exchange device, H2 is a second heat exchange device, H3 is a third heat exchange device, H4 is a fourth heat exchange device; MIX is a mixer; V1 is a water removal device; V2 is a carbon dioxide removal device; C1 is a compressor; R1 is an ethylene direct oxidation reactor; FEED is an ethylene ethane mixed feed; C2H4 is an ethylene product; C2H6 is an ethane product; MIXER is a mixture of ethylene and ethane;

[0021] 1 is a mixture of heat-exchanged ethylene and ethane; O2 is a pure oxygen feed; 2 is heat-exchanged oxygen; 3 is a mixture of ethylene, ethane and oxygen; 4 is a reactant; 5 is a product after the reaction is completed; 6 is a feed gas; 7 is a column top gas mixture; 8 is water-washed ethylene oxide; 9 is a reaction cycle gas; 10 is a reaction cycle gas re-entering the mixer; 11 is an ethylene oxide stripping column top gas; 12 is a liquid mixture; 13 is a gas impurity; 14 is an ethylene oxide product. DETAILED DESCRIPTION

[0022] An ethane-stabilized side-line ethylene-ethylene oxide combined system and method is provided as follows Figure 1The method provides a new ethane-stabilized side-line ethylene-ethylene oxide combined system and method, which comprises an ethylene-ethane separation system, an ethylene direct oxidation system for generating ethylene oxide and an ethylene oxide refining system. The ethylene-ethane separation system comprises an ethylene-ethane rectification tower with a side-line product; the ethylene direct oxidation system for generating ethylene oxide comprises a mixer, a drying device, a carbon dioxide removal device, an ethylene direct oxidation reactor, an ethylene oxide absorption tower, a plurality of heat exchangers and a compressor; and the ethylene oxide refining system comprises an ethylene oxide stripping tower and an ethylene oxide refining tower. T1 is the ethylene-ethane rectification tower; T2 is the ethylene oxide absorption tower; T3 is the ethylene oxide stripping tower; T4 is the ethylene oxide refining tower; H1, H2, H3 and H4 are heat exchange devices; MIX is the mixer; V1 is the drying device; V2 is the carbon dioxide removal device; C1 is the compressor; and R1 is the ethylene direct oxidation reactor. The process comprises the following steps: ethylene and ethane mixed raw materials FEED derived from other processes enter the ethylene-ethane rectification tower T1 with a side-line product for separation; C2H4 product (more than 99.95 wt%) is collected at the top of the tower; C2H6 product (more than 99.95 wt%) is collected at the bottom of the tower; according to the operation of subsequent chemical equipment, the side-line stream MIXER is collected by using different molar ratios; at the start-up, the ethylene-ethane in the side-line stream MIXER of the ethylene-ethane rectification tower T1 is preheated in H1, mixed with the pure oxygen O2 stream preheated by the second heat exchange device H2 in the mixer MIX, dried and dehydrated in the drying device V1, and then introduced into the ethylene direct oxidation reactor R1 for reaction; the reaction heat generated by the ethylene direct oxidation reactor R1 is partially taken away by the heat-removing agent outside the reactor, and then the temperature is lowered in the third heat exchange device H3; the feed gas 6 generated after the reaction passes through the ethylene oxide absorption tower T2 to wash away the ethylene oxide 8; the gas mixture 7 at the top of the absorption tower is subjected to carbon dioxide removal in the carbon dioxide absorption device V2, compressed by the compressor C1 and heated and pressurized by the fourth heat exchange device H4 to return to the mixer MIXER as the reaction circulating gas 10; the ethylene and a small amount of ethane consumed in the process are separated in the MIXER in the ethylene-ethane rectification tower T1; the stream 1 preheated in the first heat exchange device H1 is mixed with the reaction circulating gas 10 and the oxygen 2 after heat exchange in the second heat exchange device H2 in the mixer MIX, and then the above reaction is repeated for circulation; and the water-washed ethylene oxide 8 is refined by the ethylene oxide stripping tower T3 and the ethylene oxide refining tower T4 to obtain the ethylene oxide product 14. Figure 1 In the formula, H2O-OUT is the water removed by the water removal device; COOL-IN is the heat-removing agent entering the ethylene direct oxidation reactor; COOL-OUT is the heat-removing agent leaving the ethylene direct oxidation reactor; H2O is the clean water absorbent entering the ethylene oxide absorption tower; and CO2 represents the removed carbon dioxide.

[0023] The method of this invention reduces energy consumption and improves overall economic efficiency while ensuring reaction safety. The technical solution of this invention will be described in detail below with reference to specific embodiments. These specific embodiments are only used to explain the invention, but the scope of protection of this invention is not limited to these embodiments.

[0024] The method provided by this invention involves first selecting a suitable stabilizing gas, and then determining the maximum permissible oxygen concentration under safe conditions based on the molar concentration of ethylene and the type of stabilizing gas. Figure 3 As shown; next, during start-up, ensure that the side-stream product of the ethylene ethane distillation column has a certain molar ratio of ethane and ethylene, and thoroughly mix it with externally added pure oxygen in a suitable molar ratio to form reactants. Then, the reactants are fed into a tubular fixed-bed reactor. By controlling the reaction temperature, pressure, and space velocity, ensure that the reactor outlet yields ethylene oxide that meets industrial requirements. Subsequently, in steady state, the stabilizing gas ethane circulates back to the reactor inlet. At this time, it is necessary to change the molar ratio of ethylene and ethane in the side-stream product of the ethylene ethane distillation column to ensure that the amount of ethylene and ethane in the side-stream product can compensate for the amount of ethylene and ethane consumed in the stabilizing gas during the circulation process. Thoroughly mix it with externally added pure oxygen in a suitable molar ratio to form reactants. This process requires ensuring that the molar ratio of stabilizing gas in the reactants is the same as that of the reactants entering the reactor during start-up. Then, the reactants are fed into a tubular fixed-bed reactor. By controlling the reaction temperature, pressure, and space velocity, ensure that the reactor outlet yields ethylene oxide that meets industrial requirements.

[0025] Example 1

[0026] Nitrogen was selected as the stabilizing gas, and the molar ratios of nitrogen, ethylene, and oxygen were 74.7%, 17.4%, and 7.9%, respectively. The ethylene, oxygen, and nitrogen in the above molar ratios were introduced into the premixed gas to form reactants. At this stage, the reaction poses no explosion hazard. The top product of the ethylene-ethane distillation column is pure ethylene, and the bottom product is pure ethane, with no side streams. The reaction gas was then introduced into a tubular reactor, with the reactor inlet temperature controlled at 200°C, the reaction pressure at 2.1 MPa, and the space velocity at 4200 h⁻¹. -1 At this point, the reaction outlet temperature is 250.3℃, and the ethylene oxide outlet concentration is 0.71%. When the feed to the ethylene-ethane distillation column is 4029.51 kmol / hr, and the molar ratio of ethylene to ethane is 57.6% and 42.4% respectively, and the top and bottom of the column are guaranteed to be pure ethylene and pure ethane with a mass purity of 99.95%, the heat load of the top condenser is -4.84e+07 kJ / hr, and the heat load of the bottom reboiler is 6.40e+07 kJ / hr.

[0027] Example 2

[0028] Methane gas is selected as the stabilizing gas, and the molar ratio of methane, ethylene and oxygen is 70.6%, 19.3% and 10.1%; the above-mentioned ethylene, oxygen and nitrogen gas with the molar ratio is introduced into the pre-mixed gas to form the reactant, and at this time the reaction is not dangerous; at this time the ethylene and ethane rectification column top product is pure ethylene, and the bottom product is pure ethane, and there is no side line extraction. The reaction gas is introduced into the tube reactor, the reactor inlet temperature is controlled at 200°C, the reaction pressure is 2.1 MPa, and the space velocity is 4200h -1 At this time the reaction outlet temperature is 250.3°C, and the ethylene oxide outlet concentration is 1.0%. When the ethylene and ethane rectification column feed is 4029.51 kmol / hr, and the molar ratio of ethylene and ethane is 57.6% and 42.4% respectively, and the mass purity of the top and bottom of the column is 99.95% pure ethylene and pure ethane, the top condenser heat load is-4.84e+07kJ / hr, and the bottom reboiler heat load is 6.40e+07kJ / hr.

[0029] Example 3

[0030] Ethane gas is selected as the stabilizing gas, and the molar ratio of ethane, ethylene and oxygen is 64.2%, 22.9% and 12.9%; the above-mentioned ethylene, oxygen and nitrogen gas with the molar ratio is introduced into the pre-mixed gas to form the reactant, and at this time the reaction is not dangerous; at this time the ethylene and ethane rectification column top product is pure ethylene, and the bottom product is pure ethane, and there is no side line extraction. The reaction gas is introduced into the tube reactor, the reactor inlet temperature is controlled at 200°C, the reaction pressure is 2.1 MPa, and the space velocity is 4200h -1 At this time the reaction outlet temperature is 250.3°C, and the ethylene oxide outlet concentration is 1.51%. When the ethylene and ethane rectification column feed is 4029.51 kmol / hr, and the molar ratio of ethylene and ethane is 57.6% and 42.4% respectively, and the mass purity of the top and bottom of the column is 99.95% pure ethylene and pure ethane, the top condenser heat load is-4.84e+07kJ / hr, and the bottom reboiler heat load is 6.40e+07kJ / hr.

[0031] Example 4

[0032] Ethane gas is selected as the stabilizing gas, and the molar ratio of ethane, ethylene and oxygen is 64.2%, 22.9% and 12.9%; the above-mentioned ethylene, oxygen and nitrogen gas with the molar ratio is introduced into the pre-mixed gas to form the reactant, and at this time the reaction is not dangerous; at this time the ethylene and ethane rectification column top product is pure ethylene, and the bottom product is pure ethane, and there is no side line extraction. The reaction gas is introduced into the tube reactor, the reactor inlet temperature is controlled at 200°C, the reaction pressure is 2.1 MPa, and the space velocity is 4200h -1The reaction outlet temperature is 250.3°C and the ethylene oxide outlet concentration is 1.51% at this time. When starting up, the ethylene-ethane rectification column is fed with 4029.51 kmol / hr of ethylene and ethane at a molar ratio of 57.6% and 42.4%, respectively, and the overhead and bottom of the column are ensured to be pure ethylene and pure ethane at a mass purity of not less than 99.95%. At this time, the molar ratio of ethylene and ethane in the side line is 31.3% and 68.7%, the overhead condenser heat load is -3.34e+07 kJ / hr, and the bottom reboiler heat load is 3.83e+07 kJ / hr. When running stably, the molar ratio of ethylene and ethane in the side line is 98.77% and 1.23%, the overhead condenser heat load is -4.83e+07 kJ / hr, and the bottom reboiler heat load is 6.27e+07 kJ / hr.

[0033] Comparative Example 1, Example 2 and Example 3

[0034] The maximum allowable oxygen content of the reaction is an important indicator for evaluating the quality of the ethylene direct oxidation reaction. By comparing Examples 1, 2 and 3, it can be seen that, under the same conditions of inlet molar flow, temperature, pressure, space velocity and outlet temperature, the ethane-stabilized gas phase not only increases the maximum allowable oxygen concentration, but also improves the conversion rate of the reaction, thereby improving the economic efficiency of the process under the premise of ensuring safety.

[0035] Comparative Example 3, Example 4

[0036] In the process of preparing ethylene oxide by ethylene direct oxidation method, when ethane is used as the stabilizing gas, the ethylene-ethane rectification column for supplying the reaction raw materials can be used for side line product withdrawal. When the ethylene-ethane column is separated at an overhead of 99.95% (wt) ethylene and a bottom of 99.95% (wt) ethane, the energy consumption is an overhead condenser heat load of -4.84e+07 kJ / hr and a bottom reboiler heat load of 6.40e+07 kJ / hr. When ethane is used as the stabilizing gas and side line withdrawal is performed, the overhead condenser heat load is -3.34e+07 kJ / hr and the bottom reboiler heat load is 3.83e+07 kJ / hr when starting up, and the overhead condenser heat load is -4.83e+07 kJ / hr and the bottom reboiler heat load is 6.27e+07 kJ / hr when running stably. It can be seen that a large amount of energy consumption is saved whether starting up or running stably.

Claims

1. An ethane-stabilized side draw ethylene-ethane oxide co- system characterized by, The ethane stabilizing side line ethylene-ethylene oxide combined system comprises three parts of an ethylene-ethane separation system, an ethylene direct oxidation system for generating ethylene oxide and an ethylene oxide refining system; the ethylene-ethane separation system comprises an ethylene-ethane rectifying column (T1) with a side line product taken out; the ethylene direct oxidation system for generating ethylene oxide comprises a mixer (MIX), a drying device (V1), a carbon dioxide removal device (V2), an ethylene direct oxidation reactor (R1), an ethylene oxide absorption column (T2), a plurality of heat exchange devices and a compressor (C1); the ethylene oxide refining system comprises an ethylene oxide stripping column (T3) and an ethylene oxide refining column (T4); The side line product of the ethylene-ethane rectifying column (T1) and pure oxygen are respectively heat exchanged in respective heat exchange devices, mixed in the mixer (MIX), and then the obtained mixture is introduced into the ethylene direct oxidation reactor (R1) through the drying device (V1), and then heat exchanged in the third heat exchange device (H3) and introduced into the ethylene oxide absorption column (T2); the overhead product of the ethylene oxide absorption column (T2) is introduced into the carbon dioxide removal device (V2), sequentially passes through the compressor (C1) and the fourth heat exchange device (H4) and then is recycled back to the mixer (MIX) for recycling; the bottom product of the ethylene oxide absorption column (T2) is introduced into the ethylene oxide stripping column (T3), and the overhead of the ethylene oxide stripping column (T3) is introduced into the ethylene oxide refining column (T4).

2. An ethane-stabilized side draw ethylene-ethane oxide co- process characterized by, Ethylene and ethane mixed raw material enters ethylene-ethane rectification column (T1) with side product extraction to be separated; ethylene product is extracted from the top of ethylene-ethane rectification column (T1), ethane product is extracted from the bottom of ethylene-ethane rectification column (T1), the side product of ethylene-ethane rectification column (T1) is extracted in different molar ratios, the ethylene and ethane extracted from the side are mixed to form a mixture, the mixture is exchanged by first heat exchange device (H1) to obtain exchanged ethylene and ethane mixture (1); pure oxygen is exchanged by second heat exchange device (H2) to obtain exchanged oxygen (2); the exchanged ethylene and ethane mixture (1) and exchanged oxygen (2) are mixed in a mixer (MIX) in a certain proportion to obtain a mixture of ethylene, ethane and oxygen (3); the mixture is dried by drying device (V1) to obtain reactant (4); the reactant (4) is input into ethylene direct oxidation reactor (R1) to react, wherein the ethane acts as a stabilizing gas, part of the reaction heat generated by the reaction is taken away by the heat-removing agent outside the reactor, the product (5) after the reaction is exchanged by third heat exchange device (H3) to obtain feed gas (6); the feed gas (6) is input into ethylene oxide absorption column (T2) to wash away ethylene oxide at the bottom; the gas mixture (7) at the top of ethylene oxide absorption column (T2) is removed of carbon dioxide by carbon dioxide removal device (V2), and then is compressed by compressor (C1) to become reaction circulating gas (9) with increased temperature and pressure, and then is exchanged by fourth heat exchange device (H4) to become reaction circulating gas (10) re-entering the mixer, and returns to the mixer (MIX); the ethylene and ethane consumed in the whole process are supplemented by the side stream of ethylene-ethane rectification column (T1); the ethylene oxide (8) washed out by the water of ethylene oxide absorption column (T2) is input into ethylene oxide stripping column (T3), and liquid mixture (12) is extracted from the bottom of ethylene oxide stripping column (T3); the gas (11) at the top of ethylene oxide stripping column is input into ethylene oxide refining column (T4), gas impurities (13) are extracted from the top of ethylene oxide refining column (T4), and ethylene oxide product (14) is obtained from the bottom of ethylene oxide refining column (T4).

3. The ethane-stabilized side line ethylene-ethylene oxide co- process of claim 2, wherein, The molar ratio of ethane in the ethylene and ethane mixed raw material is 1% to 99%, and the rest is ethylene.

4. The ethane-stabilized side line ethylene-ethylene oxide co- process of claim 2 or 3, characterized by, The molar ratio of ethane in the ethylene and ethane extracted from the side of ethylene-ethane rectification column (T1) is 0% to 80%.

5. The ethane-stabilized side line ethylene-ethylene oxide co- process of claim 4, wherein, The molar ratio of ethylene in the reactants (4) entering the ethylene direct oxidation reactor (R1) is 5% to 50%, and the rest is oxygen and stabilizing gas; after mixing ethylene, oxygen and stabilizing gas, there is no explosion danger; the reaction temperature in the ethylene direct oxidation reactor (R1) is 150 to 250℃, the reaction pressure is 1.5Mpa to 2.5Mpa, the space velocity is 10 to 50000h -1 .

6. The ethane-stabilized side line ethylene-ethylene oxide co- process of claim 2, 3, or 5, wherein, The ethylene direct oxidation reactor (R1) is a tubular fixed bed reactor, and the catalyst therein is a silver catalyst.

7. The ethane-stabilized side line ethylene-ethylene oxide co- process of claim 6, wherein, The molar concentration of dichloroethane EDC inhibitor in the ethylene direct oxidation reactor (R1) is 0 to 3.5E-04%.

8. The ethane-stabilized side line ethylene-ethylene oxide co- process of claim 2, 3, 5, or 7, wherein, The separation mode of ethylene-ethane rectification column (T1) is precision separation.

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