Reclaimed water recycling system matched with production of ethylene oxide and ethylene glycol

Abstract

The utility model relates to the field of ethylene oxide and ethylene glycol production sewage treatment, and discloses a reclaimed water recycling system matched with ethylene oxide and ethylene glycol production, which comprises a reclaimed water regulating tank (31), a hardness removal sedimentation tank (32), an ozone water inlet tank (33), an ozone contact tank (34) and a reclaimed water post-positioned CBR tank (35) which are sequentially connected, and the reclaimed water post-positioned CBR tank (35) is connected with an RO (reverse osmosis) membrane treatment tank (36). Fresh water discharged from the RO membrane treatment tank (36) is recycled to a low-salt wastewater treatment system (10), and concentrated water discharged from the RO membrane treatment tank (36) is connected to an RO concentrated water hardness removal tank (37); the reclaimed water recycling system not only realizes recycling of circulating water in multiple places, but also can cooperate with efficient treatment of low-salt wastewater and efficient treatment of high-salt wastewater to recycle clear water, so that water saving and emission reduction are realized, the operation cost is reduced, and the treatment efficiency is high.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment in ethylene oxide and ethylene glycol production, specifically to a wastewater reuse system for ethylene oxide and ethylene glycol production. Background Technology

[0002] Ethylene glycol and ethylene oxide (EO and EG) are important raw materials for polyester production in chemical fiber enterprises. The main production technology related to ethylene oxide / ethylene glycol is the ethylene oxidation method, which uses ethylene and oxygen as raw materials to produce ethylene oxide (EO). EO is then converted to ethylene glycol (EG) through traditional hydration or catalytic hydrolysis. This production process continuously discharges large amounts of wastewater. This wastewater has a high concentration of organic matter, a high pH value, and a wide range of water quality fluctuations; it has a low concentration of dissolved solids; it is basically free of biologically toxic pollutants, and its BOD / COD ratio is between 0.4 and 0.6, making it suitable for biological treatment and reuse.

[0003] Existing technology, such as Chinese utility model patent application number CN201120138628.X, discloses an ethylene glycol wastewater treatment device, mainly composed of a collection well, a hydrolysis acidification tank, a biological fluidized bed reactor, a water purifier, and a clear water tank. This utility model device has low investment and low operating costs, but its treatment capacity is relatively low and its operation is not stable enough. From the perspectives of technological development trends and occupational safety and health, how to reduce wastewater discharge, lower enterprise production costs, improve the operating environment of wastewater treatment processes, and enhance the operational stability of treatment devices has become an urgent problem for chemical enterprises to solve. Utility Model Content

[0004] To address the shortcomings of existing technologies, the purpose of this utility model is to provide a wastewater reuse system for ethylene oxide and ethylene glycol production. This wastewater reuse system not only enables the reuse of circulating water in multiple locations, but also facilitates the efficient treatment of low-salt wastewater and high-salt wastewater, resulting in water conservation, emission reduction, lower operating costs, and high treatment efficiency.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] A greywater reuse system for ethylene oxide and ethylene glycol production includes a greywater equalization tank, a hardening sedimentation tank, an ozone inlet tank, an ozone contact tank, and a greywater post-CBR tank connected in sequence. The greywater post-CBR tank is connected to an RO membrane treatment tank. The effluent from the RO membrane treatment tank is reused in a low-salinity wastewater treatment system, and the concentrate from the RO membrane treatment tank is connected to an RO concentrate hardening removal tank to achieve greywater reuse.

[0007] Preferably, the RO membrane treatment tank includes a greywater inlet tank, an ultrafiltration permeate tank, and an RO permeate tank connected in sequence. The effluent from the greywater inlet tank passes through sand filtration, ultrafiltration, and RO membrane to produce concentrated water, which is then connected to the RO concentrated water hardening tank. The ultrafiltration permeate enters the ultrafiltration permeate tank, and the RO membrane permeate enters the RO permeate tank. The permeate is reused or recycled to a low-salinity wastewater treatment system.

[0008] Preferably, the hardening sedimentation tank includes multiple sets of stirring tanks and clarification tanks connected in sequence, and a second filter assembly is provided at the top of the clarification tank. The water outlet above the second filter assembly is connected to the ozone inlet tank.

[0009] Preferably, the RO concentrate hardening tank includes an RO coagulation reaction zone and an RO concentrate settling zone. A third filter component is provided on the RO concentrate settling zone, and the effluent above the third filter component is connected to a high-salt wastewater treatment system.

[0010] Preferably, the mixing tank, clarification tank and the bottom sludge of the RO concentrate settling zone are connected to a hard sludge removal tank to remove hardness from the water.

[0011] Preferably, the effluent from the sludge removal tank is connected to a collection tank, which in turn is connected to a greywater regulating tank.

[0012] Preferably, the sludge at the bottom of the sludge removal tank is connected to a plate and frame filter press via a pump body to dewater the sludge before it is discharged.

[0013] Preferably, the plate and frame filter press is connected to the filtrate tank, and the effluent from the filtrate tank is reused in the greywater equalization tank.

[0014] Preferably, the ozone contact tank includes at least three tanks, and a third circulating water device is provided between adjacent tanks and between the ozone contact tank and the ozone inlet tank to realize the wastewater circulation treatment between the tanks.

[0015] Compared with the prior art, the beneficial effects of this utility model are:

[0016] This utility model's greywater reuse system not only enables the reuse of circulating water in multiple locations, but also can be combined with the efficient treatment of low-salt wastewater and the efficient treatment of high-salt wastewater for clean water reuse, saving water and reducing emissions, lowering operating costs, and achieving high treatment efficiency. Attached Figure Description

[0017] Figure 1 This is a flowchart of the wastewater reuse system.

[0018] Figure 2 This is a partial process of the wastewater reuse system. Figure 1 .

[0019] Figure 3 This is a partial process of the wastewater reuse system. Figure 2 .

[0020] Figure 4 This is a partial process of the wastewater reuse system. Figure 3 .

[0021] Figure 5 This is the overall flow diagram of the wastewater treatment system.

[0022] In the attached diagram: 31-Grey water equalization tank, 32-hardness removal sedimentation tank, 321-second filter assembly, 33-ozone inlet tank, 34-ozone contact tank, 341-third circulating water equipment, 35-grey water post-CBR tank, 36-RO membrane treatment tank, 361-grey water inlet tank, 362-ultrafiltration permeate tank, 363-RO permeate tank, 37-RO concentrate hardness removal tank, 371-RO coagulation reaction zone, 372-RO concentrate settling zone, 373-third filter assembly; 10-low salinity wastewater treatment system, 20-high salinity wastewater treatment system, 4-other sludge tanks, 5-hardness removal sludge tank, 6-plate and frame filter press, 7-filtrate tank, 8-collection tank, 9-screw press. Detailed Implementation

[0023] Example 1: A preferred embodiment of this utility model provides a greywater reuse system for ethylene oxide and ethylene glycol production, comprising a greywater equalization tank 31, a hardening sedimentation tank 32, an ozone inlet tank 33, an ozone contact tank 34, and a greywater post-CBR tank 35 connected in sequence. The greywater post-CBR tank 35 is connected to an RO membrane treatment tank 36. The freshwater from the RO membrane treatment tank 36 is reused in a low-salinity wastewater treatment system 10, and the concentrated water from the RO membrane treatment tank 36 is connected to an RO concentrated water hardening removal tank 37 to achieve greywater reuse.

[0024] The hardening sedimentation tank 32 includes multiple sets of stirring tanks and clarification tanks connected in sequence. A second filter component 321 is provided at the top of the clarification tank, and the water outlet above the second filter component 321 is connected to the ozone inlet tank 33. The RO concentrate hardening tank 37 includes an RO coagulation reaction zone 371 and an RO concentrate settling zone 372. A third filter component 373 is provided on the RO concentrate settling zone 372, and the water outlet above the third filter component 373 is connected to the high-salt wastewater treatment system 20.

[0025] Example 2: A preferred embodiment of this utility model provides a wastewater reuse system for ethylene oxide and ethylene glycol production, which differs from the above embodiment only in that:

[0026] The RO membrane treatment tank 36 includes a greywater inlet tank 361, an ultrafiltration product water tank 362, and an RO product water tank 363 connected in sequence. The effluent from the greywater inlet tank 361 passes through sand filtration, ultrafiltration, and RO membrane to produce concentrated water, which is then connected to the RO concentrated water hardening tank 37. The ultrafiltration produced fresh water enters the ultrafiltration product water tank 362, and the RO membrane produced fresh water enters the RO product water tank 363. The fresh water is reused or recycled to the low-salinity wastewater treatment system 10.

[0027] Example 3: A preferred embodiment of this utility model provides a wastewater reuse system for ethylene oxide and ethylene glycol production, which differs from the above embodiments only in that:

[0028] The mixing tank, clarification tank and RO concentrate settling zone 372 are connected to the bottom sludge removal tank 5 to remove hardness from the water; the effluent from the sludge removal tank 5 is connected to the water collection tank 8, and the water collection tank 8 is connected to the greywater regulating tank 31; the sludge at the bottom of the sludge removal tank 5 is connected to the plate and frame filter press 6 through the pump body to dewater the sludge and discharge it.

[0029] The plate and frame filter press 6 is connected to the filtrate tank 7, and the effluent from the filtrate tank 7 is reused in the greywater equalization tank 31.

[0030] Example 4: A preferred embodiment of this utility model provides a wastewater reuse system for ethylene oxide and ethylene glycol production, which differs from the above embodiments only in that:

[0031] The ozone contact tank 34 includes at least three tanks, and a third circulating water device 341 is provided between adjacent tanks and between the ozone contact tank 34 and the ozone inlet tank 33 to realize the wastewater circulation treatment between the tanks.

[0032] This wastewater reuse system not only enables the reuse of circulating water in multiple locations, but also can be combined with the efficient treatment of low-salt wastewater and high-salt wastewater for clean water reuse, saving water and reducing emissions, lowering operating costs, and achieving high treatment efficiency.

[0033] The above description is only a specific embodiment of the present invention, but the technical features of the present invention are not limited thereto. Any changes or modifications made by those skilled in the art within the scope of the present invention are covered by the patent scope of the present invention.

Claims

1. A wastewater reuse system for ethylene oxide and ethylene glycol production, characterized in that, The system includes a greywater equalization tank (31), a hardness removal sedimentation tank (32), an ozone inlet tank (33), an ozone contact tank (34), and a greywater post-processing CBR tank (35) connected in sequence. The greywater post-processing CBR tank (35) is connected to an RO membrane treatment tank (36). The freshwater from the RO membrane treatment tank (36) is reused in the low-salt wastewater treatment system (10). The concentrated water from the RO membrane treatment tank (36) is connected to an RO concentrated water hardness removal tank (37) to achieve greywater reuse.

2. According to claim 1, the RO membrane treatment tank (36) includes a greywater inlet tank (361), an ultrafiltration product water tank (362), and an RO product water tank (363) connected in sequence. The effluent from the greywater inlet tank (361) passes through sand filtration, ultrafiltration, and RO membrane to produce concentrated water, which is then connected to the RO concentrated water hardening tank (37). The ultrafiltration produced fresh water enters the ultrafiltration product water tank (362), and the RO membrane produced fresh water enters the RO product water tank (363). The fresh water is reused or recycled to a low-salt wastewater treatment system (10).

3. The wastewater reuse system for ethylene oxide and ethylene glycol production according to claim 1, characterized in that, The hardening sedimentation tank (32) includes multiple sets of stirring tanks and clarification tanks connected in sequence. A second filter assembly (321) is provided at the top of the clarification tank, and the water outlet above the second filter assembly (321) is connected to the ozone inlet tank (33).

4. The wastewater reuse system for ethylene oxide and ethylene glycol production according to claim 3, characterized in that, The RO concentrate hardening tank (37) includes an RO coagulation reaction zone (371) and an RO concentrate settling zone (372). A third filter assembly (373) is provided on the RO concentrate settling zone (372), and the effluent above the third filter assembly (373) is connected to a high-salt wastewater treatment system (20).

5. A wastewater reuse system for ethylene oxide and ethylene glycol production according to claim 4, characterized in that, The mixing tank, clarification tank and RO concentrate settling zone (372) are connected to the bottom sludge removal tank (5) to remove hardness from the water.

6. A wastewater reuse system for ethylene oxide and ethylene glycol production according to claim 5, characterized in that, The effluent from the sludge removal tank (5) is connected to the water collection tank (8), and the water collection tank (8) is connected to the greywater regulating tank (31).

7. A wastewater reuse system for ethylene oxide and ethylene glycol production according to claim 5, characterized in that, The sludge at the bottom of the hardened sludge tank (5) is connected to a plate and frame filter press (6) via a pump body to dewater the sludge before it is discharged.

8. A wastewater reuse system for ethylene oxide and ethylene glycol production according to claim 7, characterized in that, The plate and frame filter press (6) filters water and connects to the filtrate tank (7), and the effluent from the filtrate tank (7) is reused in the greywater regulating tank (31).

9. A wastewater reuse system for ethylene oxide and ethylene glycol production according to claim 1, characterized in that, The ozone contact tank (34) includes at least three tanks, and a third circulating water device (341) is provided between adjacent tanks and between the ozone contact tank (34) and the ozone inlet tank (33) to realize the wastewater circulation treatment between the tanks.

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