Carbonate system energy-saving equipment of ethylene oxide device

Abstract

The utility model discloses energy-saving equipment for a carbonate system of an ethylene oxide device, which belongs to the technical field of chemical production equipment and is characterized in that a preheating heat exchanger is used for preheating a carbonate-rich solution and then sending the carbonate-rich solution to a carbon dioxide desorption tower through a first pipeline; the carbon dioxide desorption tower kettle pump is communicated with a carbon dioxide desorption tower kettle, the carbon dioxide desorption tower kettle pump conveys tower kettle liquid to the carbon dioxide absorption tower through a conveying pipeline, and waste water at the top of the carbon dioxide desorption tower is conveyed to a tower top condenser through a pipeline to be cooled and then enters a carbon dioxide emptying tank; the middle lower part of the carbon dioxide desorption tower is communicated with carbonate solution accurate preparation equipment through a second pipeline, the bottom of the carbonate solution accurate preparation equipment is communicated with a carbonate solution delivery pump, and the carbonate solution delivery pump is communicated with the carbon dioxide desorption tower through a third pipeline; the technical problem that the carbon dioxide removal effect is reduced due to reduction of the carbonate concentration along with normal operation cycle of a carbonate system is solved.

Description

Technical Field

[0001] This utility model belongs to the technical field of chemical production equipment, specifically relating to an energy-saving device for the carbonate system of an ethylene oxide plant. Background Technology

[0002] In ethylene oxide plants, the carbonate circulation system is one of the three major circulation systems. Carbonates can absorb carbon dioxide produced by side reactions, thereby promoting the main reaction. In existing ethylene oxide plants, the carbonate concentration in the carbonate system decreases with the increase of the operating cycle, resulting in poor carbon dioxide removal. This leads to low catalyst selectivity and activity, inhibiting the main reaction and promoting the side reaction. Usually, increasing the steam volume and raising the desorption temperature are used to improve the removal effect, but the above methods are ineffective and the steam consumption is far higher than the design value. Therefore, the existing technology cannot guarantee the efficient long-term operation of the carbonate system in ethylene oxide plants. Based on this, our company has developed an energy-saving device for the carbonate system of ethylene oxide plants that can operate for a long period of time to replace the existing technology. Utility Model Content

[0003] Purpose of the utility model: The purpose of this utility model is to provide an energy-saving device for the carbonate system of an ethylene oxide plant, so as to solve the technical problem that the carbon dioxide removal effect is reduced due to the normal decrease in carbonate concentration during the operation cycle.

[0004] The above-mentioned technical objective of this utility model is achieved through the following technical solution: an energy-saving device for the carbonate system of an ethylene oxide plant, comprising a carbon dioxide desorption tower, a carbonate solution precision preparation device, and a carbon dioxide venting tank, characterized in that a preheating heat exchanger preheats the carbonate-rich solution and then sends it to the carbon dioxide desorption tower through a first pipeline; one end of a vacuum ejector is connected to the carbon dioxide desorption tower, and the other end of the vacuum ejector is connected to a first steam pipeline; a first flow meter and a first flow valve are arranged on the first steam pipeline; the carbon dioxide desorption tower heats the solution through a reboiler; the reboiler receives heating steam from a second steam pipeline; a fifth flow meter and a fifth flow valve are arranged on the second steam pipeline; a carbon dioxide desorption tower bottom pump is connected to the bottom of the carbon dioxide desorption tower; the carbon dioxide desorption tower bottom pump delivers the bottom liquid to the carbon dioxide absorption tower through a delivery pipeline; a second flow meter and a second flow valve are arranged on the delivery pipeline.

[0005] The wastewater from the top of the carbon dioxide stripping tower is sent to the top condenser for cooling via pipeline and then enters the carbon dioxide vent tank. The wastewater in the carbon dioxide vent tank is discharged for treatment through the external discharge pipeline, and an external pump is installed on the external discharge pipeline.

[0006] The carbonate solution precision preparation equipment introduces additives A and B from the outside. The lower part of the carbon dioxide stripping tower is connected to the carbonate solution precision preparation equipment through a second pipeline. A third flow meter and a third flow valve are installed on the second pipeline. The bottom of the carbonate solution precision preparation equipment is connected to the carbonate solution delivery pump, which is connected to the carbon dioxide stripping tower through the third pipeline.

[0007] Furthermore, a branch line is connected to the second pipeline from the external discharge pipeline, and a first gate valve and a first online analyzer are arranged on the branch line.

[0008] Furthermore, a second online analyzer is also installed on the delivery pipeline.

[0009] Furthermore: a fourth flow control valve is arranged on the third pipeline, and a level gauge is installed in the carbonate solution precision preparation equipment.

[0010] Furthermore: a return line is connected to the third pipeline, and a second gate valve is arranged on the return line.

[0011] Compared with the prior art, this utility model has the following advantages: By adding a precise carbonate solution preparation device and a second online analyzer, when the density value detected by the second online analyzer is lower than the standard value, the new precise carbonate solution preparation device introduces additive 1 and additive 2 from the outside. The wastewater generated by the carbonate desorption tower is introduced into the precise carbonate solution preparation device. Under the action of the carbonate solution delivery pump, the water, additive 1 and additive 2 are uniformly mixed in the circulation process of the return pipeline and the precise carbonate solution preparation device. The uniformly mixed carbonate solution is sent to the carbonate desorption tower through the third pipeline to supply carbon dioxide removal, ensuring the removal rate, reducing the flow rate of steam and circulating carbonate, and reducing operating energy consumption. Because the structure of this application is more reasonable, the production cost is lower, making it suitable for widespread promotion and application. Attached Figure Description

[0012] Figure 1 This is a structural diagram of the utility model.

[0013] In the diagram: 1. Preheating heat exchanger; 2. First pipeline; 3. Carbon dioxide stripping tower; 4. Vacuum ejector; 5. First steam pipeline; 6. First flow meter; 7. First flow valve; 8. Reboiler; 9. Carbon dioxide stripping tower bottom pump; 10. Delivery pipeline; 11. Second flow meter; 12. Second flow valve; 13. Tower top condenser; 14. Carbon dioxide vent tank; 15. External discharge pipeline; 16. External delivery pump; 17. Carbonate solution precision preparation equipment; 18. Second pipeline; 19. Third flow meter; 20. Third flow valve; 21. Carbonate solution delivery pump; 22. Third pipeline; 23. Fourth flow control valve; 24. Level gauge; 25. Branch pipeline; 26. First gate valve; 27. First online analyzer; 28. Second online analyzer; 29. ​​Second gate valve; 30. Return pipeline; 31. Second steam pipeline; 32. Fifth flow meter; 33. Fifth flow valve. Detailed Implementation

[0014] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the protection scope of the present utility model.

[0015] In the description of this utility model, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used solely for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0016] Example 1:

[0017] like Figure 1As shown, an energy-saving device for the carbonate system of an ethylene oxide plant includes a carbon dioxide desorption tower 3, a carbon dioxide vent tank 14, and a carbonate solution precision preparation device 17. The device is characterized in that a preheating heat exchanger 1 preheats the carbonate-rich solution and then sends it to the carbon dioxide desorption tower 3 via a first pipeline 2. One end of a vacuum ejector 4 is connected to the carbon dioxide desorption tower 3, and the other end is connected to a first steam pipeline 5. A first flow meter 6 and a first flow valve 7 are arranged on the first steam pipeline 5. The carbon dioxide desorption tower 3 heats the solution through a reboiler 8, which receives heating steam from a second steam pipeline 31. A fifth flow meter 32 and a fifth flow valve 33 are arranged on the second steam pipeline 31. A carbon dioxide desorption tower bottom pump 9 is connected to the bottom of the carbon dioxide desorption tower 3. The carbon dioxide desorption tower bottom pump 9 delivers the bottom liquid to the carbon dioxide absorption tower via a conveying pipeline 10. A second flow meter 11 and a second flow valve 12 are arranged on the conveying pipeline 10. A second online analyzer 28 is also arranged on the conveying pipeline 10.

[0018] Wastewater from the top of the carbon dioxide stripping tower 3 is sent to the top condenser 13 via pipeline for cooling and then enters the carbon dioxide vent tank 14. Wastewater in the carbon dioxide vent tank 14 is discharged for treatment through the discharge pipeline 15. An external pump 16 is installed on the discharge pipeline 15. A branch pipeline 25 is connected to the discharge pipeline 15 and is connected to the second pipeline 18. A first gate valve 26 and a first online analyzer 27 are installed on the branch pipeline 25.

[0019] The carbonate solution precision preparation device 17 introduces auxiliary agent A and auxiliary agent B from the outside. The lower part of the carbon dioxide stripping tower 3 is connected to the carbonate solution precision preparation device 17 through the second pipeline 18. A third flow meter 19 and a third flow valve 20 are installed on the second pipeline 18. The bottom of the carbonate solution precision preparation device 17 is connected to the carbonate solution delivery pump 21. The carbonate solution delivery pump 21 is connected to the carbon dioxide stripping tower 3 through the third pipeline 22. A fourth flow control valve 23 is arranged on the third pipeline 22. The carbonate solution precision preparation device 17 is equipped with a level gauge 24. A return pipeline 30 is connected to the third pipeline 22. A second gate valve 29 is arranged on the return pipeline 30.

[0020] By adopting the above technical solution, the specific implementation of this utility model is as follows: the lean carbonate solution in the carbon dioxide absorption tower absorbs carbon dioxide from the reaction gas of the ethylene oxide unit to produce a rich carbonate solution. The rich carbonate solution is heated by heat exchanger 1 and then sent to carbon dioxide desorption tower 3 through first pipeline 2. The carbon dioxide desorption tower 3 creates a vacuum environment by vacuum ejector 4 to reduce the temperature required for carbon dioxide desorption. Steam is introduced through steam pipeline 31 to heat the solution in reboiler 8 and then supplied to carbon dioxide desorption tower 3 to raise the temperature and desorb carbon dioxide. During the carbon dioxide desorption operation.

[0021] Carbon dioxide stripping tower 3 strips carbonates at 105℃ and 53Kpa. When the removal rate of carbon dioxide stripping tower 3 is lower than 95% and the density detected by the second online analyzer 28 is lower than the alarm value, it is determined that the carbonate concentration is insufficient to complete the absorption and stripping of the current section. At this time, carbonate is prepared by carbonate solution precision preparation equipment 17. Additive 1 and additive 2 are added to carbonate solution precision preparation equipment 17 from the outside according to the ratio. At the same time, gate valve 26 is opened, and wastewater discharged by external pump 26 flows from branch pipe 25 into the second pipeline 18 and then into carbonate solution precision preparation equipment 1. 7. Open gate valve 29, start carbonate solution transfer pump 21 and run it in the minimum reflux line of reflux line 30 for 2 hours. After mixing evenly, open the fourth flow control valve 23 and close gate valve 29. The evenly mixed solution is sent to carbon dioxide stripping tower 3 through third pipeline 22. At this time, it is necessary to increase the load of carbon dioxide stripping tower reboiler 8. By controlling the opening of flow meter 32 and flow valve 33, the amount of steam entering reboiler 8 is increased to concentrate the solution in reboiler 8. The concentration time is 2 hours. Repeat the above steps until the concentration of the data detected by the second online analyzer 28 reaches the qualified target value.

[0022] After passing the test, the amount of steam entering the reboiler 8 is reduced by controlling the opening of the flow meter 32 and the flow valve 33. At this time, the removal rate of carbon dioxide stripping tower 3 reaches 99% to 100%, and the amount of steam added to reboiler 8 is reduced by 3% to 5%.

[0023] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements can be made without departing from the principle of the present utility model, and these improvements should also be considered within the protection scope of the present utility model.

Claims

1. An energy-saving device for the carbonate system of an ethylene oxide plant, comprising a carbon dioxide stripping tower (3), a carbon dioxide venting tank (14), and a carbonate solution precision preparation device (17), characterized in that, The preheating heat exchanger (1) preheats the carbonate-rich solution and sends it to the carbon dioxide desorption tower (3) through the first pipeline (2). One end of the vacuum ejector (4) is connected to the carbon dioxide desorption tower (3), and the other end of the vacuum ejector (4) is connected to the first steam pipeline (5). A first flow meter (6) and a first flow valve (7) are arranged on the first steam pipeline (5). The carbon dioxide desorption tower (3) heats the solution through the reboiler (8). The reboiler (8) receives heating steam from the second steam pipeline (31). A fifth flow meter (32) and a fifth flow valve (33) are arranged on the second steam pipeline (31). The carbon dioxide desorption tower bottom pump (9) is connected to the bottom of the carbon dioxide desorption tower (3). The carbon dioxide desorption tower bottom pump (9) delivers the bottom liquid to the carbon dioxide absorption tower through the conveying pipeline (10). A second flow meter (11) and a second flow valve (12) are arranged on the conveying pipeline (10). Wastewater from the top of the carbon dioxide stripping tower (3) is sent to the top condenser (13) via pipeline for cooling and then enters the carbon dioxide vent tank (14). Wastewater in the carbon dioxide vent tank (14) is discharged through the external discharge pipeline (15) for treatment. An external pump (16) is installed on the external discharge pipeline (15). The carbonate solution precision preparation equipment (17) introduces additives A and B from the outside. The lower part of the carbon dioxide desorption tower (3) is connected to the carbonate solution precision preparation equipment (17) through the second pipeline (18). A third flow meter (19) and a third flow valve (20) are installed on the second pipeline (18). The bottom of the carbonate solution precision preparation equipment (17) is connected to the carbonate solution delivery pump (21). The carbonate solution delivery pump (21) is connected to the carbon dioxide desorption tower (3) through the third pipeline (22).

2. The energy-saving equipment for the carbonate system of an ethylene oxide plant according to claim 1, characterized in that: A branch line (25) is connected to the external discharge pipeline (15) and communicates with the second pipeline (18). A first gate valve (26) and a first online analyzer (27) are arranged on the branch line (25).

3. The energy-saving equipment for the carbonate system of an ethylene oxide plant according to claim 2, characterized in that: A second online analyzer (28) is also arranged on the delivery pipeline (10).

4. The energy-saving equipment for the carbonate system of an ethylene oxide plant according to claim 2, characterized in that: A fourth flow control valve (23) is arranged on the third pipeline (22), and a level gauge (24) is arranged on the carbonate solution precision preparation equipment (17).

5. The energy-saving equipment for the carbonate system of an ethylene oxide plant according to claim 2, characterized in that: A return line (30) is connected to the third pipeline (22), and a second gate valve (29) is arranged on the return line (30).

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