EOEG product elastic switching device

Abstract

The invention relates to the technical field of ethylene oxide production, in particular to an EOEG product elastic switching device which comprises a 1 # ethylene oxide device, a 2 # ethylene oxide device, a 3 # ethylene oxide device, an ethylene glycol device I and an ethylene glycol device II, the first ethylene oxide device and the second ethylene oxide device are connected with the first ethylene glycol device and the second ethylene glycol device respectively, and an intercommunication line is connected between the first ethylene glycol device and the second ethylene glycol device. The structure of the ethylene oxide product is effectively adjusted, and energy waste is avoided, so that the effects of reducing cost and improving efficiency are achieved, the difficulty that the product structure cannot be changed due to external environment factors is greatly solved, and the change of the market condition of the EOEG market is better coped with.

Description

Technical Field

[0001] The invention relates to the technical field of ethylene oxide production, and in particular to an EOEG product elastic switching device. Background Art

[0002] Ethylene oxide (EO) is an organic chemical raw material second only to polyethylene and polyvinyl chloride among ethylene industrial derivatives. Its main downstream product is ethylene glycol (EG), which accounts for about 70% of the total EO consumption. At the same time, other major downstream products of EO include aliphatic polyoxyethylene ether (AEO) surfactants, ethanolamine, polyethylene glycol and ethylene glycol ether. These derivatives can be used as chemical raw materials to produce other fine chemical products, and can also be used directly as products. At present, the construction of ethylene oxide plants is developing in the direction of scale and technology, and the annual production scale is mostly above 200,000 tons, which greatly enhances the economic efficiency of my country's ethylene glycol plants and its ability to compete in the future market. As a high-profit product, ethylene oxide has attracted a lot of investment. In the future, my country will have a large number of new ethylene oxide plants; therefore, it faces the pressure of overcapacity and operational difficulties. This stimulates us to further explore and deepen the breadth and depth of the downstream application fields of ethylene oxide; on the other hand, it requires us to further adjust the production process of our own plants, optimize the energy system, reduce the energy consumption of the plants, and improve the competitiveness of enterprises.

[0003] Due to geographical factors, market expectations, and maintenance of ethylene glycol plants at home and abroad, the supply and demand of ethylene glycol has been fluctuating for a long time, which has also led to fluctuations in the price of ethylene glycol. Therefore, there is an urgent need for a switching device to facilitate producers to switch the products produced by the production equipment between ethylene oxide and ethylene glycol to maximize benefits. Summary of the invention

[0004] The purpose of the present invention is to provide an EOEG product elastic switching device, which has the characteristic of being able to perform elastic switching between EO and EG products.

[0005] The above technical objectives of the present invention are achieved through the following technical solutions: an EOEG product elastic switching device, including a 1# ethylene oxide unit, a 2# ethylene oxide unit and a 3# ethylene oxide unit, the 3# ethylene oxide unit is connected to the 1# ethylene oxide unit and the 2# ethylene oxide unit respectively, and also includes an ethylene glycol unit 1 and an ethylene glycol unit 2, the 1# ethylene oxide unit and the 2# ethylene oxide unit are connected to the ethylene glycol unit 1 and the ethylene glycol unit 2 respectively, and an interconnection line is connected between the ethylene glycol unit 1 and the ethylene glycol unit 2.

[0006] Preferably, the ethylene glycol device comprises an ethylene glycol reactor, a first-effect evaporation tower, a second-effect evaporation tower, a third-effect evaporation tower, a fourth-effect evaporation tower, an ethylene glycol pre-dehydration tower, a pre-dehydration tower kettle pump, a dehydration tower inlet pipeline, an ethylene glycol dehydration tower, a dehydration tower kettle pump, and an ethylene glycol refining tower;

[0007] The second ethylene glycol unit includes a second ethylene glycol reactor, a second first-effect evaporation tower, a second second-effect evaporation tower, a second third-effect evaporation tower, a second fourth-effect evaporation tower, a second ethylene glycol pre-dehydration tower, a second pre-dehydration tower kettle pump, a second dehydration tower inlet pipeline, a second ethylene glycol dehydration tower, a second dehydration tower kettle pump, and a second ethylene glycol refining tower.

[0008] Preferably, both ends of the interconnecting line are connected to the dehydration tower inlet pipeline 1 and the dehydration tower inlet pipeline 2 respectively.

[0009] Preferably, a spherical joint 1 and a spherical joint 2 are respectively provided on the dehydration tower inlet pipeline 1 and the dehydration tower inlet pipeline 2, the spherical joint 1 has a valve 1, a valve 2 and a valve 3, the spherical joint 2 has a valve 4, a valve 5 and a valve 6, the interfaces at the valve 3 and the valve 6 are respectively connected to the two ends of the interconnecting line, an interconnecting material pipe is provided in the interconnecting line, the two ends of the interconnecting material pipe are respectively connected to the joints at the valve 3 and the valve 6, each end of the interconnecting material pipe has a connecting pipe, the two ends of the interconnecting material pipe are connected to the spherical joint 1 and the spherical joint 2 through the connecting pipe, the diameter of the connecting pipe is smaller than the interconnecting material pipe, and the end of each interconnecting material pipe is externally connected to a cleaning pipe 1 and a cleaning pipe 2, and the cleaning pipe 1 and the cleaning pipe 2 have a valve 7 and a valve 8 respectively.

[0010] Preferably, the shell sides at both ends of the interconnecting line are connected with circulation pipeline 1 and circulation pipeline 2.

[0011] Preferably, the 3# ethylene oxide unit is connected with a reflux line, a first aldehyde discharge line, a liquid discharge line, a second aldehyde discharge line, and a third aldehyde discharge line. The reflux line, the first aldehyde discharge line, the liquid discharge line, the second aldehyde discharge line, and the third aldehyde discharge line are connected to a cooler and are connected to the 1# ethylene oxide unit and the 2# ethylene oxide unit respectively through a buffer tank and an aqueous solution delivery pump.

[0012] Preferably, the ethylene glycol reactor 1 and the ethylene glycol reactor 2 are adiabatic tubular reactors.

[0013] Preferably, a regulating valve is provided on the feed pipeline of the ethylene glycol reactor 1 and the ethylene glycol reactor 2, and a thermometer is provided at the inlet and outlet thereof.

[0014] Preferably, the first-effect evaporation tower 1, the second-effect evaporation tower 1, the third-effect evaporation tower 1, and the fourth-effect evaporation tower 1 are multi-effect evaporations; the first-effect evaporation tower 2, the second-effect evaporation tower 2, the third-effect evaporation tower 2, and the fourth-effect evaporation tower 2 are multi-effect evaporations.

[0015] Preferably, after the first-effect evaporation tower 1 and the first-effect evaporation tower 2 are heated for concentration, the tower top pressure is 1.55-1.95MPaG, the tower bottom temperature is 200-216°C, and a total ethylene glycol aqueous solution with a concentration of 13.33wt% is produced; the ethylene glycol aqueous solution after the first dehydration enters the second-effect evaporation tower 1 and the second-effect evaporation tower 2, the tower top pressure is 1.0-1.45MPaG, the tower bottom temperature is 190-205°C, and a total ethylene glycol aqueous solution with a concentration of 17.09wt% is produced; the ethylene glycol aqueous solution after the second dehydration enters the third-effect evaporation tower 1 and the third-effect evaporation tower 2, the tower top pressure is 0.75-0.97MPaG, the tower bottom temperature is 175-188°C, and a total ethylene glycol aqueous solution with a concentration of 24.78wt% is produced; the ethylene glycol aqueous solution after the third dehydration enters the fourth-effect evaporation tower 1 and the fourth The ethylene glycol aqueous solution after four dehydration enters the ethylene glycol pre-dehydration tower one and the ethylene glycol pre-dehydration tower two, with the tower top pressure of 0.4-0.6 MPaG and the tower bottom temperature of 164-172°C, producing a total ethylene glycol aqueous solution with a concentration of 47.35wt%; the ethylene glycol aqueous solution after four dehydration enters the ethylene glycol pre-dehydration tower one and the ethylene glycol pre-dehydration tower two, with the tower top pressure of 0.08-0.16 MPaG and the tower bottom temperature of 135-145°C, producing a total ethylene glycol aqueous solution with a concentration of 75.96wt%; the ethylene glycol aqueous solution after pre-dehydration enters the ethylene glycol dehydration tower one and the ethylene glycol dehydration tower two, with the tower top pressure of 0.01-0.015 MPaG and the tower bottom temperature of 137-145°C, producing a total ethylene glycol aqueous solution with a concentration of 99.99wt%, and enters the ethylene glycol refining tower one and the ethylene glycol refining tower two for separation of ethylene glycol, and diethylene glycol is produced in the subsequent device.

[0016] In summary, the present invention has the following beneficial effects: compared with the existing process, the EOEG product flexible switching device has small equipment investment, occupies a small space, effectively adjusts the product structure of ethylene oxide, avoids energy waste, thereby achieving the effect of reducing costs and increasing efficiency, and greatly solves the dilemma of not being able to change the product structure due to external environmental factors, so as to better cope with changes in the EOEG market, solve the technical barriers of flexible switching of EO and EG products, ensure the realization of technical breakthroughs in EO and EG products during the period of sustained growth in the future, maximize the company's interests, and create tens of millions of yuan of value for the company each year; at the same time, it saves about hundreds of millions of yuan in electricity and steam energy consumption each year. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic diagram of the connection relationship of each device in Example 1;

[0018] Figure 2 is a schematic diagram of the interconnection line in Example 2;

[0019] Figure 3 yes Figure 2 Enlarged schematic diagram of part A in the middle.

[0020] In the figure, 1, ethylene glycol reactor 1; 3, first-effect evaporation tower 1; 5, second-effect evaporation tower 1; 7, third-effect evaporation tower 1; 9, fourth-effect evaporation tower 1; 11, ethylene glycol pre-dehydration tower 1; 13, pre-dehydration tower kettle pump 1; 14, dehydration tower inlet pipeline 1; 15, ethylene glycol dehydration tower 1; 16, interconnection line; 17, ethylene glycol reactor 2; 19, first-effect evaporation tower 2; 21, second-effect evaporation tower 2; 23, third-effect evaporation tower 2; 25, fourth-effect evaporation tower 2; 27, ethylene glycol pre-dehydration tower 2; 29, pre-dehydration tower kettle pump 2; 30, dehydration tower inlet pipeline 2; 31, ethylene glycol dehydration tower 2; 33, dehydration tower kettle pump 2; 35, ethylene glycol reactor 2 Alcohol refining tower two; 38. Aqueous solution delivery pump; 40. Buffer tank; 42. Cooler; 43. Reflux line; 44. Formaldehyde discharge line one; 45. Drain line; 46. Formaldehyde discharge line two; 47. Formaldehyde discharge line three; 49. Ethylene glycol refining tower one; 50. Dehydration tower kettle pump one; 61. Ball joint one; 62. Ball joint two; 71. Valve one; 72. Valve two; 73. Valve three; 74. Valve four; 75. Valve five; 76. Valve six; 77. Valve seven; 78. Valve eight; 81. Interconnecting material pipe; 82. Circulation pipeline one; 83. Circulation pipeline two; 84. Connecting pipe; 85. Cleaning pipeline one; 86. Cleaning pipeline two. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0022] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

[0023] Embodiment 1:

[0024] like Figure 1 As shown, an EOEG product flexible switching process technology includes 1# ethylene oxide unit, 2# ethylene oxide unit, 3# ethylene oxide unit, ethylene glycol unit 1, and ethylene glycol unit 2.

[0025] The 3# ethylene oxide unit is connected to the cooler 42 through the reflux line 43, the aldehyde discharge line 1 44, the drainage line 45, the aldehyde discharge line 2 46, and the aldehyde discharge line 3 47, and then connected to the 1# ethylene oxide unit and the 2# ethylene oxide unit respectively through the buffer tank 40 and the aqueous solution delivery pump 38. The reflux line 43 is connected to the tower bottom reflux tank of the 3# ethylene oxide unit for conveying the tower bottom liquid. The aldehyde discharge line 1 44 is connected to the refining tower reflux tank of the 3# ethylene oxide unit. The drainage line 45 is connected to the tower bottom of the venting absorption tower of the 3# ethylene oxide unit. The aldehyde discharge line 2 46 is connected to the refining tower reflux tank of the 3# ethylene oxide. The aldehyde discharge line 3 47 is connected to the tower bottom of the refining tower of the 3# ethylene oxide unit.

[0026] The 1# ethylene oxide unit is connected to the ethylene glycol unit, and is connected in sequence to the ethylene glycol reactor-1, the first-effect evaporation tower-3, the second-effect evaporation tower-5, the third-effect evaporation tower-7, the fourth-effect evaporation tower-9, the ethylene glycol pre-dehydration tower-11, the pre-dehydration tower kettle pump-13, the dehydration tower inlet pipeline-14, the ethylene glycol dehydration tower-15, the dehydration tower kettle pump-50, and the ethylene glycol refining tower-49.

[0027] The 2# ethylene oxide unit is connected to the ethylene glycol unit 2, and is connected in sequence to the ethylene glycol reactor 2 17, the first-effect evaporation tower 2 19, the second-effect evaporation tower 21, the third-effect evaporation tower 23, the fourth-effect evaporation tower 25, the ethylene glycol pre-dehydration tower 27, the pre-dehydration tower kettle pump 2 29, the dehydration tower inlet pipeline 2 30, the ethylene glycol dehydration tower 2 31, the dehydration tower kettle pump 2 33, and the ethylene glycol refining tower 2 35.

[0028] An interconnection line 16 is connected between the dehydration tower inlet pipeline 14 and the dehydration tower inlet pipeline 2 30 .

[0029] The ethylene glycol reactor 1 and the ethylene glycol reactor 2 17 are adiabatic tubular reactors.

[0030] The feed pipelines of the ethylene glycol reactor 1 and the ethylene glycol reactor 2 17 are respectively provided with regulating valves, and the inlet and outlet are provided with thermometers.

[0031] The first effect evaporation tower 13, the second effect evaporation tower 15, the third effect evaporation tower 17, and the fourth effect evaporation tower 19 are multi-effect evaporation. The first effect evaporation tower 21, the second effect evaporation tower 23, and the fourth effect evaporation tower 25 are also multi-effect evaporation.

[0032] The reboilers used in the first-effect evaporation tower 3, the second-effect evaporation tower 5, the third-effect evaporation tower 7, the fourth-effect evaporation tower 9, the glycol pre-dehydration tower 11, and the glycol dehydration tower 15 are high-flux reboilers. The reboilers used in the first-effect evaporation tower 21, the second-effect evaporation tower 23, the fourth-effect evaporation tower 25, the glycol pre-dehydration tower 27, and the glycol dehydration tower 231 are high-flux reboilers.

[0033] The working principle of this embodiment is as follows: the outlet temperature of ethylene glycol reactor 1 and ethylene glycol reactor 2 17 is 224.5°C. The reaction product of ethylene glycol aqueous solution in ethylene glycol reactor 1 and ethylene glycol reactor 2 17 is used as the heat source of first-effect evaporation tower 3 and first-effect evaporation tower 2 19, and the top process steam of first-effect evaporation tower 3 and first-effect evaporation tower 2 19 is used as the heat source of second-effect evaporation tower 5 and second-effect evaporation tower 21. The operating pressure of each evaporation tower is reduced in sequence with a certain gradient, and so on. The top process steam of triple-effect evaporation tower 7 and triple-effect evaporation tower 2 23 is used as the heat source of quadruple-effect evaporation tower 9 and quadruple-effect evaporation tower 25, and part of the top process steam of quadruple-effect evaporation tower 9 and quadruple-effect evaporation tower 2 25 is used as the heat source of ethylene glycol pre-dehydration tower 11 and ethylene glycol pre-dehydration tower 27. The EG content of the kettle liquid in the first-effect evaporation tower 13 and the first-effect evaporation tower 2 19 is 12.24wt%, and then it enters the second-effect evaporation tower 15, the second-effect evaporation tower 21, the third-effect evaporation tower 17, the third-effect evaporation tower 23, the fourth-effect evaporation tower 19, the fourth-effect evaporation tower 25 and the ethylene glycol pre-dehydration tower 11, the ethylene glycol pre-dehydration tower 2 27 in sequence, and the ethylene glycol is concentrated to 69.61wt%. After the first-effect evaporation tower 3 and the first-effect evaporation tower 2 19 are heated and concentrated, the tower top pressure is 1.55-1.95MPaG, the tower bottom temperature is 200-216°C, and a total ethylene glycol aqueous solution with a concentration of 13.33wt% is produced; the ethylene glycol aqueous solution after the first dehydration enters the second-effect evaporation tower 5 and the second-effect evaporation tower 21, the tower top pressure is 1.0-1.45MPaG, the tower bottom temperature is 190-205°C, and a total ethylene glycol aqueous solution with a concentration of 17.09wt% is produced; the ethylene glycol aqueous solution after the second dehydration enters the third-effect evaporation tower 7 and the third-effect evaporation tower 23, the tower top pressure is 0.75-0.97MPaG, the tower bottom temperature is 175-188°C, and a total ethylene glycol aqueous solution with a concentration of 24.78wt% is produced; the ethylene glycol aqueous solution after the third dehydration enters the fourth-effect evaporation tower 9 and the fourth-effect evaporation tower 2 25, the tower top pressure is 0.4-0.6MPaG, the tower bottom temperature is 164-172℃, and the total ethylene glycol aqueous solution with a concentration of 47.35wt% is produced; the ethylene glycol aqueous solution after four dehydration enters the ethylene glycol pre-dehydration tower 11 and the ethylene glycol pre-dehydration tower 27, the tower top pressure is 0.08-0.16MPaG, the tower bottom temperature is 135-145℃, and the total ethylene glycol aqueous solution with a concentration of 75.96wt% is produced; the ethylene glycol aqueous solution after pre-dehydration enters the ethylene glycol dehydration tower 15 and the ethylene glycol dehydration tower 31, the tower top pressure is 0.01-0.015MPaG, the tower bottom temperature is 137-145℃, and the total ethylene glycol aqueous solution with a concentration of 99.99wt% is produced, and enters the ethylene glycol refining tower 49 and the ethylene glycol refining tower 35 to separate ethylene glycol, and diethylene glycol is produced in the subsequent device.

[0034] When the producer wants to produce more EO products, most of the EO products are directly extracted from the 1# ethylene oxide unit, the 2# ethylene oxide unit, and the 3# ethylene oxide unit, and the flow rate is reduced by the regulating valve to reduce the EO products entering the ethylene glycol reactor 1 and the ethylene glycol reactor 2 17. At the same time, the interconnection line 16 is opened, the connection of the ethylene glycol refining tower 1 49 or the ethylene glycol refining tower 2 35 is cut off, and only one of the ethylene glycol refining towers is activated to reduce the output of the EG product.

[0035] When the producer wants to produce more EG products, the flow rate is increased by adjusting the valve to increase the EO products entering the ethylene glycol reactor 1 and the ethylene glycol reactor 2 17. At the same time, the interconnection line 16 is cut off, and the ethylene glycol refining tower 1 49 and the ethylene glycol refining tower 2 35 are put into use at the same time to increase the production speed of the EG products.

[0036] Through the above-mentioned flexible switching, an industrial layout that is both EO and EG suitable has been achieved.

[0037] Embodiment 2:

[0038] like Figure 2 and Figure 3 As shown, the two ends of the interconnection line 16 are respectively provided with ball joints, including ball joint 1 61 and ball joint 2 62, which are respectively connected to the dehydration tower inlet pipeline 1 14 and the dehydration tower inlet pipeline 2 30. The ball joint is a three-way joint with three interfaces, and each interface is provided with a valve. The three interfaces of the ball joint 1 61 are provided with valve 1 71, valve 2 72, and valve 3 73, and the three interfaces of the ball joint 2 62 are provided with valve 4 74, valve 5 75, and valve 6 76. The joints at valve 1 71 and valve 2 72 are connected to the dehydration tower inlet pipeline 1 14. Valve 4 74 and valve 5 75 are connected to the dehydration tower inlet pipeline 2 30. The interfaces at valve 3 73 and valve 6 76 are respectively connected to the two ends of the interconnection line 16. The two ends of the interconnection line 16 are sealed, and an interconnection material pipe 81 is arranged in the interconnection line 16. The two ends of the interconnection material pipe 81 are respectively connected to the joints at the valve three 73 and the valve six 76. The shell side at both ends of the interconnection line 16 is connected with the circulation pipeline one 82 and the circulation pipeline two 83. Since the dehydration tower inlet pipeline one 14 and the dehydration tower inlet pipeline two 30 in the site are far away, the material gradually dissipates heat during transportation in the interconnection line 16, and the temperature decreases, resulting in the material eventually not meeting the process requirements. Therefore, high-temperature steam is input through the circulation pipeline one 82 and the circulation pipeline two 83 for heating to ensure the temperature of the material in the interconnection material pipe 81, thereby ensuring the product quality.

[0039] There are multiple interconnected material pipes 81, and each of the interconnected material pipes 81 has a connecting pipe 84 at its end. The two ends of the interconnected material pipe 81 are connected to the ball joint 1 61 and the ball joint 2 62 through the connecting pipe 84. The diameter of the connecting pipe 84 is smaller than that of the interconnected material pipe 81. The ends of each interconnected material pipe 81 are connected to a cleaning pipe 1 85 and a cleaning pipe 2 86 outwardly, and the connection between the cleaning pipe 1 85 and the cleaning pipe 2 86 and the interconnected material pipe 81 is designed to be smooth. The cleaning pipe 1 85 and the cleaning pipe 2 86 are used to inject rubber balls and cleaning water for cleaning, and the cleaning pipe 1 85 and the cleaning pipe 2 86 have a valve 7 77 and a valve 8 78 respectively.

[0040] When the device produces more EO products and less EG products, valve one 71 and valve three 73 are opened, valve two 72 is closed, valve four 74, valve five 75, and valve six 76 are opened. During the operation of the device, valve seven 77 and valve eight 78 are closed.

[0041] When the device switches from producing more EO products to producing more EG products, during the switching process, first open valve two 72 and close valve three 73. The rubber ball used to clean the interconnecting material pipe 81 is driven into the cleaning pipe one 85, and high-pressure cleaning water is connected to the feed end of the cleaning pipe. The valve seven 77 is opened, and the high-pressure cleaning water is used to push the rubber ball from the cleaning pipe one 85 to the cleaning pipe two 86. The rubber ball and the interconnecting material pipe 81 are interference fit, so that the rubber ball can wipe the inner wall of the interconnecting material pipe 81, and prevent the cleaning water from being mixed into the original material in the interconnecting material pipe 81. In the process of pushing the rubber ball to move by the high-pressure clean water, the rubber ball pushes the original material in the interconnecting material pipe 81 to the dehydration tower inlet pipeline two 30. Then close valve six 76, open valve eight 78, and discharge the used cleaning water and rubber ball. The interconnecting material pipe 81 can be cleaned multiple times according to needs. After cleaning, close valve seven 77 and valve eight 78. Close the circulation pipeline 1 82 and the circulation pipeline 2 83. Through the above operation, the original material in the intercommunication pipe 81 can be input into the dehydration tower inlet pipeline 2 30 during switching to prevent waste of materials. At the same time, the intercommunication pipe 81 is also cleaned.

Claims

1. An EOEG product elastic switching device, characterized in that: The invention comprises a 1# ethylene oxide unit, a 2# ethylene oxide unit and a 3# ethylene oxide unit, wherein the 3# ethylene oxide unit is connected to the 1# ethylene oxide unit and the 2# ethylene oxide unit respectively, and further comprises an ethylene glycol unit 1 and an ethylene glycol unit 2, wherein the 1# ethylene oxide unit and the 2# ethylene oxide unit are connected to the ethylene glycol unit 1 and the ethylene glycol unit 2 respectively, and an interconnection line (16) is connected between the ethylene glycol unit 1 and the ethylene glycol unit 2.

2. The EOEG product elastic switching device according to claim 1, characterized in that: The ethylene glycol device comprises an ethylene glycol reactor (1), a first-effect evaporation tower (3), a second-effect evaporation tower (5), a third-effect evaporation tower (7), a fourth-effect evaporation tower (9), an ethylene glycol pre-dehydration tower (11), a pre-dehydration tower kettle pump (13), a dehydration tower inlet pipeline (14), an ethylene glycol dehydration tower (15), a dehydration tower kettle pump (50), and an ethylene glycol refining tower (49); The second ethylene glycol device comprises a second ethylene glycol reactor (17), a second first-effect evaporation tower (19), a second second-effect evaporation tower (21), a second third-effect evaporation tower (23), a second fourth-effect evaporation tower (25), a second ethylene glycol pre-dehydration tower (27), a second pre-dehydration tower kettle pump (29), a second dehydration tower inlet pipeline (30), a second ethylene glycol dehydration tower (31), a second dehydration tower kettle pump (33), and a second ethylene glycol refining tower (35).

3. The EOEG product elastic switching device according to claim 2, characterized in that: The two ends of the interconnecting line (16) are respectively connected to the dehydration tower inlet pipeline 1 (14) and the dehydration tower inlet pipeline 2 (30).

4. The EOEG product elastic switching device according to claim 3, characterized in that: A spherical joint 1 (61) and a spherical joint 2 (62) are respectively arranged on the dehydration tower inlet pipeline 1 (14) and the dehydration tower inlet pipeline 2 (30). The spherical joint 1 (61) has a valve 1 (71), a valve 2 (72) and a valve 3 (73). The spherical joint 2 (62) has a valve 4 (74), a valve 5 (75) and a valve 6 (76). The interfaces at the valve 3 (73) and the valve 6 (76) are respectively connected to the two ends of the interconnection line (16). An interconnection material pipe (81) is arranged in the interconnection line (16). The two ends of the interconnection material pipe (81) are respectively The interconnecting material pipe (81) is connected to the joints at valve three (73) and valve six (76). The ends of each interconnecting material pipe (81) are provided with connecting pipes (84). The two ends of the interconnecting material pipe (81) are connected to ball joint one (61) and ball joint two (62) through connecting pipes (84). The diameter of the connecting pipe (84) is smaller than that of the interconnecting material pipe (81). The ends of each interconnecting material pipe (81) are externally connected to cleaning pipe one (85) and cleaning pipe two (86). Cleaning pipe one (85) and cleaning pipe two (86) are provided with valve seven (77) and valve eight (78) respectively.

5. The EOEG product elastic switching device according to claim 4, characterized in that: The shell sides at both ends of the interconnecting line (16) are connected to a circulation pipeline 1 (82) and a circulation pipeline 2 (83).

6. The EOEG product elastic switching device according to claim 1, characterized in that: The 3# ethylene oxide device is connected with a reflux line (43), an aldehyde discharge line 1 (44), a liquid discharge line (45), an aldehyde discharge line 2 (46), and an aldehyde discharge line 3 (47). The reflux line (43), the aldehyde discharge line 1 (44), the liquid discharge line (45), the aldehyde discharge line 2 (46), and the aldehyde discharge line 3 (47) are connected to a cooler (42), and are connected to the 1# ethylene oxide device and the 2# ethylene oxide device respectively after passing through a buffer tank (40) and an aqueous solution delivery pump (38) in sequence.

7. The EOEG product elastic switching device according to claim 2, characterized in that: The ethylene glycol reactor 1 (1) and the ethylene glycol reactor 2 (17) are adiabatic tubular reactors.

8. The EOEG product elastic switching device according to claim 2, characterized in that: The feed pipelines of the ethylene glycol reactor 1 (1) and the ethylene glycol reactor 2 (17) are provided with regulating valves, and the inlet and outlet thereof are provided with thermometers.

9. The EOEG product elastic switching device according to claim 2, characterized in that: The first-effect evaporation tower 1 (3), the second-effect evaporation tower 1 (5), the third-effect evaporation tower 1 (7), and the fourth-effect evaporation tower 1 (9) are multi-effect evaporation; the first-effect evaporation tower 2 (19), the second-effect evaporation tower 2 (21), the third-effect evaporation tower 2 (23), and the fourth-effect evaporation tower 2 (25) are multi-effect evaporation.

10. The EOEG product elastic switching process according to claim 2, characterized in that: After the first-effect evaporation tower 1 (3) and the first-effect evaporation tower 2 (19) are heated for concentration, the tower top pressure is 1.55-1.95 MPaG, the tower bottom temperature is 200-216° C., and a total ethylene glycol aqueous solution with a concentration of 13.33 wt % is produced; the ethylene glycol aqueous solution after the first dehydration enters the second-effect evaporation tower 1 (5) and the second-effect evaporation tower 2 (21), the tower top pressure is 1.0-1.45 MPaG, the tower bottom temperature is 190-205° C., and a total ethylene glycol aqueous solution with a concentration of 17.09 wt % is produced; the ethylene glycol aqueous solution after the second dehydration enters the third-effect evaporation tower 1 (7) and the third-effect evaporation tower 2 (23), the tower top pressure is 0.75-0.97 MPaG, the tower bottom temperature is 175-188° C., and a total ethylene glycol aqueous solution with a concentration of 24.78 wt % is produced; the ethylene glycol aqueous solution after the third dehydration enters the fourth-effect evaporation tower 1 (9) and the fourth-effect evaporation tower 2 (25), the tower top pressure is 0.4-0.6MPaG, the tower bottom temperature is 164-172°C, and a total ethylene glycol aqueous solution with a concentration of 47.35wt% is produced; the ethylene glycol aqueous solution after four dehydration enters the ethylene glycol pre-dehydration tower 1 (11) and the ethylene glycol pre-dehydration tower 2 (27), the tower top pressure is 0.08-0.16MPaG, the tower bottom temperature is 135-145°C, and a total ethylene glycol aqueous solution with a concentration of 75.96wt% is produced. The pre-dehydrated ethylene glycol aqueous solution enters an ethylene glycol dehydration tower 1 (15) and an ethylene glycol dehydration tower 2 (31), the tower top pressure is 0.01-0.015 MPaG, the tower bottom temperature is 137-145°C, and a total ethylene glycol aqueous solution with a concentration of 99.99 wt% is produced, and enters an ethylene glycol refining tower 1 (49) and an ethylene glycol refining tower 2 (35) to separate ethylene glycol, and diethylene glycol is extracted in a subsequent device.

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