Desulfurization wastewater zero discharge treatment system

Abstract

The utility model belongs to the field of chemical engineering, and discloses a desulfurization wastewater zero discharge treatment system, which comprises a wastewater inlet pipe, a multi-stage overflow tank and a clarification tank which are connected in sequence, an overflow port of the clarification tank is connected with a water tank, the water tank is used for providing water to an evaporation crystallizer, the evaporation crystallizer is used for concentrating and crystallizing inorganic salt in the water, and the evaporation crystallizer is used for crystallizing the inorganic salt in the water. A solid discharge port of the evaporation crystallizer is connected with a dehydration dryer; a steam outlet of the crystallizer is connected with a condenser; a middle water tank is arranged between the water tank and the evaporation crystallizer; water in the middle water tank serves as a cold source of the condenser, and the water tank is connected to a waste water inlet pipe through a backflow pipeline and a pump. According to the system, the water tank and the middle water tank are adopted, if water in the water tank does not reach the standard, the water flows back to the waste water inlet pipe, the middle water tank can serve as a buffer, the situation that no water is available for the evaporation crystallizer when the water in the water tank is not qualified is avoided, and in addition, waste heat utilization is conducted on water in the condenser, and the energy consumption of the evaporation crystallizer can be reduced.

Description

Technical Field

[0001] This utility model relates to the chemical industry, and in particular to a zero-discharge treatment system for desulfurization wastewater. Background Technology

[0002] Zero-discharge technology for desulfurization wastewater has been successfully applied in the thermal power sector. For details, please refer to:

[0003] The publication number is CN205473132U, and the subject is a zero-discharge treatment device for desulfurization wastewater. It discloses a pre-sedimentation unit, an adjustment unit, a primary flocculation sedimentation unit, a softening unit, a secondary flocculation sedimentation unit, an intermediate water tank unit, an evaporation crystallization unit, a two-stage sludge treatment unit, and a product water tank.

[0004] In this system, multi-stage flocculation is used to improve the water quality of the intermediate pool.

[0005] However, the design of multi-stage flocculation systems significantly increases the floor space required. In mature electric field retrofits, there is not much space reserved for zero-emission systems. Therefore, an acceptable compromise is needed to solve this problem. Utility Model Content

[0006] The purpose of this invention is to provide a zero-discharge treatment system for desulfurization wastewater. This system uses a water tank and an intermediate water tank. If the water in the water tank does not meet the standards, it will be returned to the wastewater inlet pipe. The intermediate water tank can act as a buffer to prevent the evaporator crystallizer from having no water when the water in the water tank is substandard. In addition, by utilizing the waste heat of the water in the condenser, the energy consumption of the evaporator crystallizer can be reduced.

[0007] To achieve the above objectives, this application discloses a zero-discharge treatment system for desulfurization wastewater, comprising a wastewater inlet pipe, a multi-stage overflow tank, and a clarification tank connected in sequence. The overflow outlet of the clarification tank is connected to a water tank, which supplies water to an evaporator crystallizer. The evaporator crystallizer is used to concentrate and crystallize inorganic salts in the water. The solid discharge outlet of the evaporator crystallizer is connected to a dehydrator. The steam discharge outlet of the crystallizer is connected to a condenser. An intermediate water tank is provided between the water tank and the evaporator crystallizer. The water in the intermediate water tank serves as a cold source for the condenser. The water tank is connected to the wastewater inlet pipe via a return pipe and a pump.

[0008] In the above-mentioned zero-discharge treatment system for desulfurization wastewater, there are two condensers connected in parallel and switched by a switching valve; the cold source for one condenser is the condensation water inside the factory; the cold source for the other condenser is the water in the intermediate water tank.

[0009] In the above-mentioned zero-discharge treatment system for desulfurization wastewater, an electromagnetic valve is installed between the water tank and the wastewater inlet pipe.

[0010] In the aforementioned zero-discharge treatment system for desulfurization wastewater, the bottom of the clarification tank is provided with a discharge outlet, which is connected to an external sludge treatment system.

[0011] In the aforementioned zero-discharge treatment system for desulfurization wastewater, the lower part of the clarification tank is a cone-shaped section, which is used to allow flocculents in the water to settle to the bottom of the cone-shaped section.

[0012] In the above-mentioned zero-discharge treatment system for desulfurization wastewater, the multi-stage overflow tank includes a pH adjustment tank, a sedimentation tank, and a flocculation tank connected in sequence; the liquid in the pH adjustment tank, sedimentation tank, and flocculation tank overflows into the next stage in sequence; the wastewater inlet pipe is connected to the pH adjustment tank; and the flocculation tank and the clarification tank are connected.

[0013] In the aforementioned zero-discharge treatment system for desulfurization wastewater, agitators are installed in the pH adjustment tank, sedimentation tank, and flocculation tank.

[0014] In the aforementioned zero-discharge treatment system for desulfurization wastewater, the bottoms of the pH adjustment tank, sedimentation tank, and flocculation tank are all connected to an external sludge treatment system.

[0015] The beneficial effects of this application are:

[0016] This solution uses a water tank and an intermediate water tank. If the water in the water tank does not meet the standards, it will flow back to the wastewater inlet pipe. The intermediate water tank can act as a buffer to prevent the evaporator crystallizer from having no water when the water in the water tank is not up to standard. In addition, by utilizing the waste heat of the water in the condenser, the energy consumption of the evaporator crystallizer can be reduced. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of Example 1. Detailed Implementation

[0018] The present invention will now be clearly and completely described in conjunction with its embodiments. It should be noted that, in this description, unless specific conditions are specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0019] Example 1

[0020] refer to Figure 1A zero-discharge treatment system for desulfurization wastewater includes a wastewater inlet pipe 1, a multi-stage overflow tank, and a clarification tank 2 connected in sequence. The overflow outlet of the clarification tank 2 is connected to a water tank 3, which provides water to an evaporator crystallizer 4. The evaporator crystallizer 4 is used to concentrate and crystallize inorganic salts in the water. The solid discharge outlet of the evaporator crystallizer 4 is connected to a dehydrator 5. The steam discharge outlet of the crystallizer is connected to a condenser 6. An intermediate water tank 7 is provided between the water tank 3 and the evaporator crystallizer 4. The water in the intermediate water tank 7 serves as a cold source for the condenser 6. The water tank 3 is connected to the wastewater inlet pipe 1 through a return pipe and a pump.

[0021] In production, to reduce the floor space required, this embodiment only sets up one multi-stage overflow tank for flocculation and sedimentation. However, this carries the risk that the water quality in tank 3 is unstable, while the evaporator crystallizer 4 has high water quality requirements, which could lead to production stoppage. To address this issue, this embodiment adds an intermediate tank 7, which collects qualified water from tank 3. Input of unqualified water is suspended. Generally, when the water in tank 3 is unqualified, it is not completely drained to wastewater inlet pipe 1, as clarifier 2 continuously replenishes water into tank 3. When water from tank 3 enters wastewater inlet pipe 1, the sludge content of the entire system is diluted, and the water quality improves after a period of time. Once the water quality in tank 3 is detected to be qualified, drainage to wastewater inlet pipe 1 is stopped, and water is instead injected into tank 3. When the water quality in tank 3 is unqualified, not only is the water returned to the wastewater discharge pipe, but the pH is also adjusted and the amount of flocculant used is increased in the multi-stage overflow tank to regulate the water quality in clarifier 2.

[0022] Preferably, there are two condensers 6 connected in parallel, and the two condensers 6 are switched by a switching valve; the cold source of one condenser 6 is the condensing water inside the factory; the cold source of the other condenser 6 is the water in the intermediate water tank 7.

[0023] In this embodiment, the water in the intermediate water tank 7 is used to condense the steam most of the time. When the water tank 3 needs to return water to the wastewater inlet pipe 1, the condenser 6 is stopped to avoid overheating of the water in the intermediate water tank 7. The condenser 6 should be switched to another condenser 6.

[0024] Preferably, a solenoid valve 8 is provided between the water tank 3 and the wastewater inlet pipe 1, and a discharge port is provided at the bottom of the clarification tank 2. The discharge port is connected to an external sludge treatment system 9. The lower part of the clarification tank 2 is a conical part 10, which is used to allow the flocculents in the water to settle at the bottom of the conical part 10. The multi-stage overflow tank includes a pH adjustment tank 11, a sedimentation tank 12, and a flocculation tank 13 connected in sequence. The liquid in the pH adjustment tank 11, sedimentation tank 12, and flocculation tank 13 overflows into the next stage in sequence. The wastewater inlet pipe 1 is connected to the pH adjustment tank 11. The flocculation tank 13 is connected to the clarification tank 2. A stirrer is provided in the pH adjustment tank 11, sedimentation tank 12, and flocculation tank 13.

[0025] The design of the aforementioned clarifier 2 and multi-stage overflow tank is conventional technology in the field, and this embodiment will not impose too many restrictions or descriptions on them. In this embodiment, preferably, the bottoms of the pH adjustment tank 11, sedimentation tank 12, and flocculation tank 13 are all connected to the external sludge treatment system 9. Under normal circumstances, the pH adjustment tank 11, sedimentation tank 12, and flocculation tank 13 do not discharge to the sludge treatment system 9. When maintenance is required, the sludge settled at the bottom needs to be discharged to the sludge treatment system 9.

[0026] To further reduce the footprint, the intermediate water tank 7 can be placed above the multi-stage overflow tank and / or clarifier 2; more preferably, in a factory environment, a steel frame can be built above the multi-stage overflow tank and clarifier 2 to support the intermediate water tank 7; the water tank 3 and the intermediate water tank 7 are connected by a pump.

Claims

1. A zero-discharge treatment system for desulfurization wastewater, comprising a wastewater inlet pipe, a multi-stage overflow tank, and a clarification tank connected in sequence, wherein the overflow outlet of the clarification tank is connected to a water tank, the water tank being used to supply water to an evaporator crystallizer, the evaporator crystallizer being used to concentrate and crystallize inorganic salts from the water, the solid discharge outlet of the evaporator crystallizer being connected to a dehydrator dryer; and the steam discharge outlet of the crystallizer being connected to a condenser; characterized in that, An intermediate water tank is provided between the water tank and the evaporator crystallizer; the water in the intermediate water tank serves as the cold source for the condenser, and the water tank is connected to the wastewater inlet pipe through a return pipe and a pump.

2. The zero-discharge treatment system for desulfurization wastewater according to claim 1, characterized in that, There are two condensers connected in parallel, and the two condensers are switched by a switching valve; the cold source of one condenser is the condensing water inside the factory; the cold source of the other condenser is the water in the intermediate water tank.

3. The zero-discharge treatment system for desulfurization wastewater according to claim 1, characterized in that, A solenoid valve is installed between the water tank and the wastewater inlet pipe.

4. The zero-discharge treatment system for desulfurization wastewater according to claim 1, characterized in that, The bottom of the clarification tank is provided with a discharge port, which is connected to an external sludge treatment system.

5. The zero-discharge treatment system for desulfurization wastewater according to claim 4, characterized in that, The lower part of the clarification tank is conical, which is used to allow flocculent matter in the water to settle to the bottom of the conical part.

6. The zero-discharge treatment system for desulfurization wastewater according to claim 1, characterized in that, The multi-stage overflow tank includes a pH adjustment tank, a sedimentation tank, and a flocculation tank connected in sequence; the liquid in the pH adjustment tank, sedimentation tank, and flocculation tank overflows into the next stage in sequence; the wastewater inlet pipe is connected to the pH adjustment tank; and the flocculation tank and the clarification tank are connected.

7. The zero-discharge treatment system for desulfurization wastewater according to claim 6, characterized in that, The pH adjustment tank, sedimentation tank, and flocculation tank are all equipped with agitators.

8. The zero-discharge treatment system for desulfurization wastewater according to claim 6, characterized in that, The bottoms of the pH adjustment tank, sedimentation tank, and flocculation tank are all connected to an external sludge treatment system.

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