Energy-saving and consumption-reducing device of by-product recovery unit

Abstract

The utility model relates to the technical field of energy conservation and consumption reduction in chemical production, in particular to an energy conservation and consumption reduction device of a byproduct recovery unit. Comprising an ether dehydration tower, an ether dehydration tower kettle pump, an ether dehydration tower reflux tank, an ether dehydration tower reflux pump, an ether extraction tower, a cooler II, an ether extraction tower reflux tank, an ether extraction tower reflux pump, an ether extraction tower wastewater pump, an ether extraction tower kettle pump and a heat exchanger II, wherein a benzene phase in the ether extraction tower reflux tank is conveyed to the ether extraction tower through the ether extraction tower reflux pump for reflux; the water phase of the ether extraction tower reflux tank is divided into two paths to be conveyed through an ether extraction tower wastewater pump, one path is connected with a benzene-containing wastewater pipeline to be conveyed to an ether dehydration tower feeding pipeline to be mixed and then conveyed to the ether dehydration tower, and the other path is conveyed to a waste liquid incineration system through a waste liquid pipeline to be incinerated; the benzene-containing waste water pipeline and the waste liquid pipeline are respectively provided with a hand valve for switching use. The benzene-containing waste water recovery device has the following beneficial effects that ether and benzene in a water phase of the return tank of the ether extraction tower can be recovered, and the energy consumption is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of energy conservation and consumption reduction in chemical production, in particular to an energy conservation and consumption reduction device for a by-product recovery unit. Background Art

[0002] Propylene oxide (PO) is an important basic organic chemical raw material and is the third largest organic chemical product among propylene derivatives, second only to polypropylene and acrylonitrile in output. It is mainly used in the production of polyether polyols, propylene glycol, polyurethane, etc., and is also the main raw material for the fourth-generation non-ionic surfactants for detergents, oilfield demulsifiers, and pesticide emulsifiers, with broad development prospects. Derivatives of propylene oxide are also widely used in industries such as food, tobacco, pesticides, and cosmetics. There are nearly a hundred downstream products, making it an important raw material for fine chemical products.

[0003] Industrially, the production processes of propylene oxide mainly include the chlorohydrin method and the co-oxidation method, accounting for about 90% of the global propylene oxide production. The process adopted by this device is the direct oxidation method of hydrogen peroxide (HPPO method), using propylene and hydrogen peroxide as raw materials and methanol as a solvent to produce propylene oxide, and by-products such as propylene glycol, monomethyl ether, and isomethyl ether are produced. After the ether-containing water material is dehydrated and extracted and separated, it is further separated through an ether product tower. The monomethyl ether product is taken out from the top of the tower, and the isomethyl ether product is taken out from the bottom of the tower.

[0004] Currently, in the existing ether recovery system of the HPPO process in this device, benzene is used as an extractant in the ether extraction tower to extract water in the ether. After the extracted benzene-water material enters the reflux tank, the benzene-water phase is layered. The benzene phase is returned as reflux to the ether extraction tower, and the water phase is treated as wastewater.

[0005] However, in the actual operation process, on the one hand, a small amount of ether will also evaporate and enter the reflux tank of the ether extraction tower with the benzene-water material, and the water phase will be discharged to the wastewater, affecting the COD of the wastewater and causing losses of the by-product ether. On the other hand, the water phase will also carry a small amount of benzene. If it directly enters the wastewater, it will damage the wastewater treatment system and cause losses of benzene at the same time. Content of the Utility Model

[0006] The purpose of the utility model is to provide an energy conservation and consumption reduction device for a by-product recovery unit, which can recover ether and benzene in the water phase of the reflux tank of the ether extraction tower.

[0007] The above technical purpose of the utility model is achieved through the following technical solutions:

[0008] An energy-saving and consumption-reducing device for a by-product recovery unit, comprising a first heat exchanger, an ether dehydration tower, an ether dehydration tower bottom pump, an ether dehydration tower reflux drum, an ether dehydration tower reflux pump, an ether extraction tower, a second cooler, an ether extraction tower reflux drum, an ether extraction tower reflux pump, an ether extraction tower waste water pump, an ether extraction tower bottom pump, a second heat exchanger and related pipelines, instruments, etc. The feed of the ether dehydration tower is connected to the ether dehydration tower through an ether dehydration tower feed pipeline. A first heat exchanger is provided in the middle of the ether dehydration tower feed pipeline to preheat the feed of the ether dehydration tower, and the first heat exchanger uses the waste water at the bottom of the ether dehydration tower for preheating; the top of the ether dehydration tower is connected to the ether dehydration tower reflux drum through an ether dehydration tower top pipeline, and a first cooler is arranged on the ether dehydration tower top pipeline; the bottom of the ether dehydration tower sends waste water to a waste water treatment system through a waste water pipeline, and the waste water pipeline is connected to the first heat exchanger and the second heat exchanger; the ether dehydration tower reflux pump and the ether extraction tower are connected through an ether extraction tower feed pipeline; the top of the ether extraction tower is connected to the ether extraction tower reflux drum through an ether extraction tower top pipeline, and the ether extraction tower top pipeline is connected to the second cooler; the benzene phase of the ether extraction tower reflux drum is transported to the ether extraction tower as reflux through an ether extraction tower reflux pump; the water phase of the ether extraction tower reflux drum is divided into two paths for transportation through an ether extraction tower waste water pump. One path is connected to a benzene-containing waste water pipeline and transported to the ether dehydration tower feed pipeline for mixing and then sent to the ether dehydration tower, and the other path is sent to a waste liquid incineration system for incineration through a waste liquid pipeline; hand valves are respectively arranged on the benzene-containing waste water pipeline and the waste liquid pipeline for switching use.

[0009] Preferably, a first flowmeter is arranged on the waste water pipeline.

[0010] Preferably, a field thermometer is arranged on the outlet pipeline of the second heat exchanger.

[0011] Preferably, a second flowmeter is arranged on the ether extraction tower feed pipeline.

[0012] Preferably, a sampler is arranged on the water phase discharge pipeline of the ether extraction tower reflux drum to analyze the contents of water, ether and benzene in the water phase.

[0013] Preferably, a third flowmeter is arranged on the water phase discharge pipeline of the ether extraction tower reflux drum.

[0014] Preferably, an interface meter is arranged on the water phase of the ether extraction tower reflux drum.

[0015] Preferably, a first hand valve is arranged on the benzene-containing waste water pipeline; a second hand valve is arranged on the waste liquid pipeline.

[0016] Preferably, a fourth flowmeter is arranged on the ether extraction tower bottom pipeline.

[0017] In summary, the utility model has the following beneficial effects:

[0018] Compared with the existing process, an energy-saving and consumption-reducing device for a by-product recovery unit provided by the present utility model optimizes the process, returns the aqueous phase of the ether extraction tower reflux tank to the system to recover the ether and benzene in the aqueous phase, and then discharges the remaining wastewater after recovery to the wastewater system, reducing the loss of ether and benzene. And when the ether dehydration tower system is abnormal or the system needs to be replaced and emptied, the aqueous phase process can be switched to the waste liquid pipeline and sent to the liquid separation and incineration system for incineration, improving the operation stability of the device. At the same time, the heat of the wastewater separated by the ether dehydration tower is used to preheat the feed of the ether dehydration tower, reducing energy loss. Description of the Drawings

[0019] Figure 1 It is a process flow diagram of the present device.

[0020] In the figure, 1. Ether dehydration tower feed pipeline; 2. Benzene-containing wastewater pipeline; 3. Heat exchanger I; 4. Ether dehydration tower; 5. Wastewater pipeline; 6. Ether dehydration tower top pipeline; 7. Cooler I; 8. Flowmeter I; 9. Ether dehydration tower bottom pump; 10. Ether dehydration tower reflux tank; 11. Ether dehydration tower reflux pump; 12. Ether extraction tower feed pipeline; 13. Flowmeter II; 14. Ether extraction tower; 15. Cooler II; 16. Ether extraction tower reflux tank; 17. Ether extraction tower reflux pump; 18. Flowmeter III; 19. Ether extraction tower top pipeline; 20. Manual valve I; 21. Manual valve II; 22. Waste liquid pipeline; 23. Ether extraction tower wastewater pump; 24. Sampler; 25. Flowmeter IV; 26. Ether extraction tower bottom pump; 27. Ether extraction tower bottom pipeline; 28. Heat exchanger II; 29. Thermometer; 30. Interface meter; 31. Benzene reflux pipeline. Detailed Embodiments

[0021] The following further describes the present utility model in detail with reference to the drawings.

[0022] This specific embodiment is only an explanation of the present utility model and does not limit the present utility model. Those skilled in the art can make modifications without creative contributions to this embodiment according to needs after reading this specification, but as long as they are within the scope of the claims of the present utility model, they are protected by the patent law.

[0023] Embodiment:

[0024] An energy-saving and consumption-reducing device for a by-product recovery unit.

[0025] The feed of the ether dehydration tower 4 is connected to the ether dehydration tower 4 through the ether dehydration tower feed pipeline 1. A heat exchanger 1-3 is provided in the middle of the ether dehydration tower feed pipeline 1 to preheat the feed of the ether dehydration tower, and the heat exchanger 1-3 uses the bottom waste water of the ether dehydration tower 4 for preheating; the top of the ether dehydration tower 4 is connected to the ether dehydration tower reflux tank 10 through the ether dehydration tower top pipeline 6, and a cooler 1-7 is provided in the ether dehydration tower top pipeline 6; the bottom of the ether dehydration tower 4 sends the waste water to the waste water treatment system through the waste water pipeline 5, and a heat exchanger 1-3 and a heat exchanger 2-28 are provided in the waste water pipeline 5; the ether dehydration tower reflux pump 11 and the ether extraction tower 14 are connected through the ether extraction tower feed pipeline 12; the top of the ether extraction tower 14 is connected to the ether extraction tower reflux tank 16 through the ether extraction tower top pipeline 19, and a cooler 2-15 is provided in the ether extraction tower top pipeline 19; the benzene phase of the ether extraction tower reflux tank 16 is transported to the ether extraction tower 14 as reflux through the ether extraction reflux pump 17; the water phase of the ether extraction tower reflux tank 16 is divided into two paths for transportation through the ether extraction tower waste water pump 23. One path is transported to the ether dehydration tower feed pipeline 1 through the benzene-containing waste water pipeline 2 and then sent to the ether dehydration tower 4 after mixing, and the other path is sent to the waste liquid incineration system for incineration through the waste liquid pipeline 22; the benzene-containing waste water pipeline 2 and the waste liquid pipeline 22 are respectively provided with manual valves for switching use.

[0026] A flowmeter 1-8 is provided in the waste water pipeline 5.

[0027] A field thermometer 29 is provided in the outlet pipeline of the heat exchanger 2-28.

[0028] A flowmeter 2-13 is provided in the ether extraction tower feed pipeline 12.

[0029] A sampler 24 is provided in the water phase discharge pipeline of the ether extraction tower reflux tank 16 to analyze the water, ether, and benzene contents in the water phase.

[0030] A flowmeter 3-18 is provided in the water phase discharge pipeline of the ether extraction tower reflux tank 16.

[0031] An interface level gauge 30 is provided in the water phase of the ether extraction tower reflux tank 16.

[0032] A manual valve 1-20 is provided in the benzene-containing waste water pipeline 2; a manual valve 2-21 is provided in the waste liquid pipeline 22.

[0033] A flowmeter 4-25 is provided in the bottom pipeline 27 of the ether extraction tower.

[0034] The working mode of the above by-product recovery unit energy-saving and consumption-reducing device is as follows:

[0035] The material temperature from the feed pipeline 1 of the ether dehydration tower is 92 - 98°C. First, it passes through the first heat exchanger 3 and is preheated by high-temperature wastewater at 115 - 125°C. After the material temperature reaches 102 - 108°C, it enters the ether dehydration tower 4. After the material is heated, evaporated and separated in the ether dehydration tower 4, the ether-containing water mixture material passes through the top pipeline 6 of the ether dehydration tower, is cooled to 115 - 120°C by the first cooler 7, and then enters the ether dehydration tower reflux tank 10. The material in the ether dehydration tower reflux tank 10 is transported by the ether dehydration tower reflux pump 11. Part of it is returned as reflux to the ether dehydration tower 4, and part of it is transported to the ether extraction tower 14 for further separation. The wastewater at the bottom of the ether dehydration tower 4 is transported by the wastewater pump 9. First, it preheats the feed of the ether dehydration tower 4 through the first heat exchanger 3, and then enters the second heat exchanger 28 for cooling before being discharged to the wastewater treatment system. The temperature of the cooled wastewater is monitored on-site by the thermometer 29 and controlled at 40 - 60°C.

[0036] The material temperature from the feed pipeline 12 of the ether extraction tower is 115 - 120°C. The material enters the ether extraction tower 14. After the material is heated, evaporated and separated in the ether extraction tower 14, the benzene-containing water mixture material passes through the top pipeline 19 of the ether extraction tower, is cooled to 20 - 30°C by the second cooler 15, and then enters the ether extraction tower reflux tank 16. The benzene-phase material in the ether extraction tower reflux tank 16 is transported by the ether extraction tower reflux pump 17 and returned as reflux to the ether extraction tower 14. The water-phase material is transported in two ways by the ether extraction tower wastewater pump 23. One way is sent to the feed pipeline 1 of the ether dehydration tower through the benzene-containing wastewater pipeline 2, and the other way is sent to the waste liquid incineration system through the waste liquid pipeline 22. During normal production, the first manual valve 20 is opened and the second manual valve 21 is closed to send the water-phase material to the ether dehydration tower 4. When the ether dehydration tower 4 fluctuates or is abnormal, the first manual valve 20 is closed and the second manual valve 21 is opened to switch the process to the waste liquid incineration system.

Claims

1. An energy-saving and consumption-reducing device for a by-product recovery unit, characterized in that It includes heat exchanger 1 (3), ether dehydration tower (4), ether dehydration tower bottom pump (9), ether dehydration tower reflux drum (10), ether dehydration tower reflux pump (11), ether extraction tower (14), cooler 2 (15), ether extraction tower reflux drum (16), ether extraction tower reflux pump (17), ether extraction tower waste water pump (23), ether extraction tower bottom pump (26), and heat exchanger 2 (28). The feed of the ether dehydration tower (4) is connected to the ether dehydration tower (4) through the ether dehydration tower feed pipeline (1). A heat exchanger 1 (3) is provided in the middle of the ether dehydration tower feed pipeline (1) to preheat the feed of the ether dehydration tower (4), and the heat exchanger 1 (3) uses the waste water at the bottom of the ether dehydration tower (4) for preheating; the top of the ether dehydration tower (4) is connected to the ether dehydration tower reflux drum (10) through the ether dehydration tower top pipeline (6), and a cooler 1 (7) is provided in the ether dehydration tower top pipeline (6); the bottom of the ether dehydration tower (4) sends the waste water to the waste water treatment system through the waste water pipeline (5), and the waste water pipeline (5) is connected to the heat exchanger 1 (3) and the heat exchanger 2 (28); the ether dehydration tower reflux pump (11) and the ether extraction tower (14) are connected through the ether extraction tower feed pipeline (12); the top of the ether extraction tower (14) is connected to the ether extraction tower reflux drum (16) through the ether extraction tower top pipeline (19), and the ether extraction tower top pipeline (19) is connected to the cooler 2 (15); the benzene phase of the ether extraction tower reflux drum (16) is transported to the ether extraction tower (14) as reflux through the ether extraction tower reflux pump (17); the water phase of the ether extraction tower reflux drum (16) is transported in two paths through the ether extraction tower waste water pump (23). One path is connected to the benzene-containing waste water pipeline (2) and transported to the ether dehydration tower feed pipeline (1) for mixing and then sent to the ether dehydration tower (4). The other path is sent to the waste liquid incineration system for incineration through the waste liquid pipeline (22); the benzene-containing waste water pipeline (2) and the waste liquid pipeline (22) are respectively provided with manual valves for switching use.

2. The energy-saving and consumption-reducing device for a by-product recovery unit according to claim 1, wherein, A flowmeter 1 (8) is provided in the waste water pipeline (5).

3. The energy-saving and consumption-reducing device for a by-product recovery unit according to claim 1, characterized in that A field thermometer (29) is provided in the outlet pipeline of the heat exchanger 2 (28).

4. The energy-saving and consumption-reducing device for a by-product recovery unit according to claim 1, characterized in that, A flowmeter 2 (13) is provided in the ether extraction tower feed pipeline (12).

5. An energy-saving and consumption-reducing device for a by-product recovery unit according to claim 1, characterized in that, A sampler (24) is provided in the water phase discharge pipeline of the ether extraction tower reflux drum (16) to analyze the water, ether, and benzene contents in the water phase.

6. The energy-saving and consumption-reducing device for a by-product recovery unit according to claim 1, wherein, A flowmeter 3 (18) is provided in the water phase discharge pipeline of the ether extraction tower reflux drum (16).

7. The energy-saving and consumption-reducing device for a by-product recovery unit according to claim 1, wherein, An interface meter (30) is provided in the water phase of the ether extraction tower reflux drum (16).

8. An energy-saving and consumption-reducing device for a by-product recovery unit according to claim 1, characterized in that, A manual valve 1 (20) is provided in the benzene-containing waste water pipeline (2); a manual valve 2 (21) is provided in the waste liquid pipeline (22).

9. The energy-saving and consumption-reducing device for a by-product recovery unit according to claim 1, characterized in that, A flowmeter 4 (25) is provided in the ether extraction tower bottom pipeline (27).

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