Low-salt wastewater treatment 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 low-salt wastewater treatment system matched with ethylene oxide and ethylene glycol production, which comprises a low-salt regulating tank (11), a biological selection tank (12), a low-salt ASR tank (13), a low-salt CBR tank (14) and a low-salt secondary sedimentation tank (15) which are sequentially connected, sludge at the bottom of the low-salt secondary sedimentation tank (15) is connected with a sludge return tank (17); the low-salt wastewater treatment system realizes efficient treatment of low-salt wastewater in ethylene oxide and ethylene glycol production, and is high in treatment efficiency and stable in operation; meanwhile, the reclaimed water recycling system (30) is matched for recycling clean water at multiple positions, so that water is saved, emission is reduced, and the operation cost is reduced.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment in the production of ethylene oxide and ethylene glycol, specifically to a low-salt wastewater treatment system for use in the production of ethylene oxide and ethylene glycol. 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 low-salt wastewater treatment system for ethylene oxide and ethylene glycol production. This system achieves efficient treatment of low-salt wastewater from ethylene oxide and ethylene glycol production, with high treatment efficiency and stable operation. Simultaneously, it is integrated with a greywater reuse system for multiple clean water reuses, saving water, reducing emissions, and lowering operating costs.

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

[0006] A low-salt wastewater treatment system for ethylene oxide and ethylene glycol production includes a low-salt equalization tank, a biological selection tank, a low-salt ASR tank, a low-salt CBR tank, and a low-salt secondary sedimentation tank connected in sequence. The effluent from the low-salt secondary sedimentation tank is connected to a high-efficiency clarification tank, and the sludge at the bottom of the low-salt secondary sedimentation tank is connected to a sludge return tank to achieve low-salt wastewater treatment.

[0007] Preferably, the high-efficiency clarification tank includes multiple sets of stirring tanks and clarification tanks connected in sequence. The sludge at the bottom of the last two sets of stirring tanks is connected to a sludge tank through pipelines so that the wastewater is stirred and clarified in sequence and the remaining sludge is treated centrally.

[0008] Preferably, the clarification tank is connected to the adjacent mixing tank through two sets of parallel partitions. The partition adjacent to the mixing tank is provided with a lower water outlet, and the partition adjacent to the clarification tank is provided with an upper water outlet, so that the clear water clarified by mixing in the mixing tank enters the clarification tank through the upper water outlet.

[0009] Preferably, a first filtration assembly is provided above the clarification tank, and the water filtration assembly is connected to an outlet weir above the first filtration assembly to filter the clear water above the clarification tank for reuse.

[0010] Preferably, the outlet weir is connected to a water recycling tank, and the outlet of the water recycling tank is connected to a greywater reuse system.

[0011] Preferably, the bottom of the sludge return tank is connected to a biological selection tank or a sludge tank via a pump to reuse or discharge the sludge.

[0012] Preferably, the effluent from the sludge tank is connected to a collection tank, and the effluent from the collection tank is reused in a greywater recycling system. The sludge at the bottom of the collection tank is connected to a screw press via a pump body to dewater the sludge before it is discharged.

[0013] Preferably, the screw press is connected to a filtrate tank, and the effluent from the filtrate tank is reused in a greywater recycling system.

[0014] Compared with the prior art, the beneficial effects of this utility model are:

[0015] This utility model's low-salt wastewater treatment system achieves efficient treatment of low-salt wastewater from ethylene oxide and ethylene glycol production, with high treatment efficiency and stable operation; at the same time, it is combined with a greywater reuse system for multiple clean water reuses, saving water and reducing emissions, and lowering operating costs. Attached Figure Description

[0016] Figure 1 This is a flowchart of the low-salt wastewater treatment system.

[0017] Figure 2 This is a partial process of the low-salinity wastewater treatment system. Figure 1 .

[0018] Figure 3 This is a partial process of the low-salinity wastewater treatment system. Figure 2 .

[0019] Figure 4 This is a partial process of the low-salinity wastewater treatment system. Figure 3 .

[0020] Figure 5 This is the overall flow diagram of the wastewater treatment system.

[0021] In the attached diagram: 11-Low-salt equalization tank, 12-Biological selection tank, 13-Low-salt ASR tank, 14-Low-salt CBR tank, 15-Low-salt secondary sedimentation tank, 16-High-efficiency clarifier, 161-Baffle plate, 162-Filter assembly, 163-Effluent weir, 17-Sludge return tank, 18-Reclaimed water tank; 30-Grey water reuse system, 4-Sludge tank, 7-Filtration tank, 8-Collection tank, 9-Screw press. Detailed Implementation

[0022] Example 1: A preferred embodiment of this utility model provides a low-salt wastewater treatment system for ethylene oxide and ethylene glycol production, comprising a low-salt equalization tank 11, a biological selection tank 12, a low-salt ASR tank 13, a low-salt CBR tank 14, and a low-salt secondary sedimentation tank 15 connected in sequence. The effluent from the low-salt secondary sedimentation tank 15 is connected to a high-efficiency clarifier 16, and the sludge at the bottom of the low-salt secondary sedimentation tank 15 is connected to a sludge return tank 17 to achieve low-salt wastewater treatment. The bottom of the sludge return tank 17 is connected to the biological selection tank 12 or the sludge tank 4 via a pump to reuse or discharge the sludge.

[0023] Example 2: A preferred embodiment of this utility model provides a low-salt wastewater treatment system for ethylene oxide and ethylene glycol production. The only difference between this system and the above embodiment is that the high-efficiency clarification tank 16 includes multiple sets of stirring tanks and clarification tanks connected in sequence. The sludge at the bottom of the last two sets of stirring tanks is connected to the sludge tank 4 through pipelines so that the wastewater is stirred and clarified in sequence and the remaining sludge is treated in a centralized manner.

[0024] The clarification tank is connected to the adjacent mixing tank through two sets of parallel partitions 161. The partition 161 adjacent to the mixing tank is provided with a lower water outlet, and the partition 161 adjacent to the clarification tank is provided with an upper water outlet, so that the clear water that has been stirred and clarified in the mixing tank can enter the clarification tank through the upper water outlet.

[0025] A first filter assembly 162 is provided above the clarification tank. The water filter above the first filter assembly 162 is connected to the outlet weir 163 to filter the clear water above the clarification tank for reuse. The outlet water of the outlet weir 163 is connected to the reuse water tank 18, and the outlet water of the reuse water tank 18 is connected to the greywater reuse system 30.

[0026] Example 3: A preferred embodiment of this utility model provides a low-salt wastewater treatment system for ethylene oxide and ethylene glycol production, which differs from the above embodiments only in that:

[0027] The effluent from the sludge tank 4 is connected to the collection tank 8. The effluent from the collection tank 8 is reused in the greywater reuse system 30. The sludge at the bottom of the collection tank 4 is connected to the screw press 9 via a pump to dewater the sludge before it is discharged. The filtered water from the screw press 9 is connected to the filtrate tank 7. The effluent from the filtrate tank 7 is reused in the greywater reuse system 30.

[0028] This system achieves efficient treatment of low-salt wastewater from ethylene oxide and ethylene glycol production. It has high treatment efficiency and stable operation. Combined with the greywater reuse system, it allows for the reuse of clean water at multiple points, saving water and reducing emissions, thus lowering operating costs.

[0029] The above description is only a specific embodiment of the present utility model, but the technical features of the present utility model are not limited thereto. Any changes or modifications made by those skilled in the art within the scope of the present utility model are covered by the patent scope of the present utility model.

Claims

1. A low-salinity wastewater treatment system for use in the production of ethylene oxide and ethylene glycol, characterized in that, The system includes a low-salt equalization tank (11), a biological selection tank (12), a low-salt ASR tank (13), a low-salt CBR tank (14), and a low-salt secondary sedimentation tank (15) connected in sequence. The effluent from the low-salt secondary sedimentation tank (15) is connected to a high-efficiency clarifier (16), and the sludge at the bottom of the low-salt secondary sedimentation tank (15) is connected to a sludge return tank (17) to achieve low-salt wastewater treatment.

2. The low-salt wastewater treatment system for ethylene oxide and ethylene glycol production according to claim 1, characterized in that, The high-efficiency clarification tank (16) includes multiple sets of mixing tanks and clarification tanks connected in sequence. The bottom sludge of the two sets of mixing tanks at the end is connected to the sludge tank (4) through pipelines so that the wastewater is stirred and clarified in sequence and the remaining sludge is treated in a centralized manner.

3. The low-salt wastewater treatment system for ethylene oxide and ethylene glycol production according to claim 2, characterized in that, The clarification tank is connected to the adjacent mixing tank through two sets of parallel partitions (161). The partition (161) adjacent to the mixing tank is provided with a lower outlet, and the partition (161) adjacent to the clarification tank is provided with an upper outlet, so that the clear water that has been stirred and clarified in the mixing tank can enter the clarification tank through the upper outlet.

4. The low-salt wastewater treatment system for ethylene oxide and ethylene glycol production according to claim 3, characterized in that, A first filter assembly (162) is provided above the clarification tank. The water filter above the first filter assembly (162) is connected to the outlet weir (163) to filter the clear water above the clarification tank and reuse it.

5. A low-salt wastewater treatment system for ethylene oxide and ethylene glycol production as described in claim 4, characterized in that, The outlet weir (163) is connected to the reclaimed water tank (18), and the outlet of the reclaimed water tank (18) is connected to the greywater reuse system (30).

6. The low-salt wastewater treatment system for ethylene oxide and ethylene glycol production according to claim 1, characterized in that, The bottom of the sludge return tank (17) is connected to the biological selection tank (12) or the sludge tank (4) via a pump to reuse or discharge the sludge.

7. A low-salt wastewater treatment system for ethylene oxide and ethylene glycol production as described in claim 2 or 6, characterized in that, The sludge tank (4) is connected to the water collection tank (8) for effluent. The effluent from the water collection tank (8) is reused in the greywater recycling system (30). The sludge at the bottom is connected to the screw press (9) via a pump body to dewater the sludge before it is discharged.

8. A low-salt wastewater treatment system for ethylene oxide and ethylene glycol production according to claim 7, characterized in that, The screw press (9) filters water and connects to the filtrate tank (7). The effluent from the filtrate tank (7) is recycled to the greywater recycling system (30) to reuse the filtered water.

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