Efficient clarification device for desulfurization wastewater

Abstract

The utility model provides an efficient desulfurization wastewater clarification device which comprises a clarification tank main body, and an upper heat exchanger, a heat exchange tube and a lower heat exchanger are sequentially arranged in an inner cavity of the clarification tank main body from top to bottom; the bottom of the heat exchange pipe is connected with a pipeline bracket, and clarification tank filler is arranged at the top of the heat exchange pipe; wherein the other end of the pipeline bracket is connected with the bottom of a sedimentation tank in the clarification tank main body; a sludge outlet is formed in the bottom of the sedimentation tank; the device can automatically clean and operate, is high in automation degree, and can specifically and efficiently precipitate desulfurization wastewater compared with a traditional precipitation tank; strong brine is used as a heat exchange medium for heat exchange, so that the temperature of the strong brine is increased, heat needed by temperature rise of the rear-end evaporation section is reduced, and the energy-saving effect is achieved.

Description

A high-efficiency clarification device for desulfurization wastewater Technical Field

[0001] This invention relates to the field of water treatment, and more particularly to a high-efficiency clarification device for desulfurization wastewater. Background Technology

[0002] Desulfurization wastewater originates from the flue gas desulfurization system of thermal power plants. It is characterized by high water temperature, high suspended solids concentration, high COD, and acidic pH. Traditional desulfurization wastewater treatment processes involve neutralization and sedimentation, followed by flocculation, clarification, and concentration. The purified water is then recycled, while the wastewater is dewatered and transported for disposal. With increasingly stringent environmental regulations in China, the demand for desulfurization wastewater treatment from coal-fired power plants is also continuously rising.

[0003] Pretreatment is the first step in treating desulfurization wastewater. This process removes suspended solids, soluble pollutants, and heavy metal ions from the wastewater, preventing them from interfering with subsequent processes. A common pretreatment technology is sedimentation, which uses a combination of chemical flocculation and physical sedimentation to remove suspended solids from the wastewater.

[0004] Although existing sedimentation tanks can achieve efficient sedimentation by adding inclined plates, some of the added coagulants and flocculants will dissolve in the water, thus affecting the quality of the products produced by subsequent zero-discharge processes, resulting in low system reuse rates and poor economic efficiency. Simultaneously, desulfurization wastewater itself has a certain viscosity and low thermal conductivity, leading to poor heat transfer. The influent temperature of the desulfurization slurry in the sedimentation tank is generally above 50℃. During sedimentation, the water temperature drops rapidly at the top and bottom, while the temperature in the middle remains higher. Due to the continuous temperature difference within the sedimentation tank, convection occurs, with hotter parts rising and colder parts sinking, resulting in high turbidity in the sedimentation tank's produced water and poor operational performance. Furthermore, the high suspended solids content of desulfurization wastewater makes the added inclined plates easily contaminated, requiring frequent drainage and manual cleaning, making long-term stable operation difficult.

[0005] The purpose of this solution is to address the following issues: low system reuse rate due to the addition of coagulants and flocculants during the operation of desulfurization wastewater clarification and pretreatment equipment; poor operational performance due to convection caused by temperature differences in the desulfurization slurry within the sedimentation tank; and easy fouling of the inclined plates due to high mud content. Summary of the Invention

[0006] To address the aforementioned issues, this invention discloses a high-efficiency clarification device for desulfurization wastewater and its application method. This device can control the temperature of desulfurization wastewater in the clarification tank in real time. Simultaneously, the design of the heat exchange tubes allows for automatic cleaning of the clarification tank packing material through water hammer, reducing convection caused by internal temperature differences and minimizing maintenance frequency, thereby achieving efficient sedimentation.

[0007] A high-efficiency clarification device for desulfurization wastewater includes a clarification tank body. The clarification tank body has an upper heat exchanger, a heat exchange tube, and a lower heat exchanger arranged sequentially from top to bottom within its inner cavity. The bottom of the heat exchange tube is connected to a pipe support, and the top is filled with clarification tank packing. The other end of the pipe support is connected to the bottom of a sedimentation tank within the clarification tank body. The bottom of the sedimentation tank has a sludge discharge port. One end of the upper heat exchanger is connected to its inlet, and the other end is connected to its outlet. One end of the heat exchange tube is connected to the inlet of a middle heat exchange tube, and the other end is connected to its outlet. One end of the lower heat exchanger is connected to the inlet of a lower heat exchange tube, and the other end is connected to its outlet. The front end of the clarification tank body has a desulfurization wastewater outlet and a desulfurization wastewater inlet arranged sequentially.

[0008] Furthermore, the inlet and outlet of the central heat exchange tube are connected to the heat exchange tube via flexible connecting pipes.

[0009] Furthermore, the flexible connecting tube is a steel wire braided tube or a plastic flexible tube.

[0010] Furthermore, a vibration damping device is installed between the pipe support and the heat exchange tube. This device is used to reduce the impact of heat exchange tube vibration on the pipe support and can be a spring, a pneumatic damper, or other vibration damping device.

[0011] Furthermore, the shock absorption device is a spring or a pneumatic damper.

[0012] Furthermore, the clarifier packing is fixed to the heat exchange tube by binding, welding, or pressing.

[0013] Furthermore, the upper heat exchanger, heat exchange tubes, and lower heat exchanger operate independently, and the heat exchange media among the three do not circulate with each other.

[0014] Furthermore, the medium in the heat exchanger is concentrated brine from the desulfurization wastewater treatment process, industrial wastewater, tap water, or other low-temperature media;

[0015] Furthermore, the packing material for the clarifier is PP inclined plate, PVC inclined plate, or steel plate.

[0016] Furthermore, temperature sensors are installed on the upper heat exchanger, heat exchange tubes, and lower heat exchanger.

[0017] A method for applying a high-efficiency clarification device for desulfurization wastewater includes the following steps:

[0018] Step 1: Desulfurization wastewater enters the clarification tank from the desulfurization wastewater inlet. After sedimentation and separation by the packing material in the clarification tank, the clear water is discharged from the desulfurization wastewater outlet and sent to the ultrafiltration device, while the sludge is discharged from the sludge outlet into the collection system.

[0019] Step 2: Concentrated brine is used as the heat exchange medium. It enters the upper heat exchanger, heat exchange tubes and lower heat exchanger through the inlet of the upper heat exchanger, the inlet of the middle heat exchange tube and the inlet of the lower heat exchange tube. The flow rate is dynamically adjusted according to the temperature sensor data.

[0020] Furthermore, when the clarifier becomes clogged, the flow rate at the inlet of the central heat exchange tube is increased, and the water hammer effect is used to vibrate the clarifier packing to achieve self-cleaning.

[0021] Furthermore, the heat exchange medium flow rate is calculated using the following formula:

[0022]

[0023] Where G is the concentrated brine flow rate in each heat exchanger, in kg / h;

[0024] G1—Flow rate of desulfurization wastewater in each heat exchanger area, kg / h;

[0025] c1——Specific heat capacity of desulfurization wastewater, kJ / (kg·℃);

[0026] c—Specific heat capacity of concentrated brine, kJ / (kg·℃);

[0027] T1, T2 — Temperature changes of desulfurization wastewater before and after passing through each heat exchange zone, kJ / (kg·℃);

[0028] t1, t2 — Temperature changes of concentrated brine before and after passing through each heat exchange zone, kJ / (kg·℃);

[0029] The flow rate of the heat exchange medium (concentrated brine) in the heat exchanger of each zone is automatically adjusted according to the temperature feedback from the temperature sensors of each zone in the above formula, thereby achieving the purpose of rapid and uniform cooling of the desulfurization wastewater in the clarification unit and reducing the problems of liquid convection and the inability of suspended matter to settle caused by internal temperature differences.

[0030] The beneficial effects of this invention are:

[0031] 1. This invention can automatically clean and operate, with a high degree of automation. Compared with traditional sedimentation tanks, it can effectively and efficiently settle desulfurization wastewater.

[0032] 2. This invention can use concentrated brine as a heat exchange medium to increase the temperature of the concentrated brine, thereby reducing the heat required for the downstream evaporation section to heat up, thus achieving energy-saving effects.

[0033] 3. This invention can complete sedimentation without adding flocculants and coagulants, which can improve the quality of subsequent resource-based products;

[0034] 4. The device of this invention has a high degree of integration and occupies a small area. Attached Figure Description

[0035] Figure 1. Front view of the high-efficiency clarification device for desulfurization wastewater;

[0036] Figure 2, a cross-sectional view of AA in Figure 1;

[0037] Figure 3, a cross-sectional view of BB in Figure 1;

[0038] Figure 4. Process flow diagram of the high-efficiency clarification system for desulfurization wastewater.

[0039] List of reference numerals in the attached diagram:

[0040] Among them, 1 is the inlet of the upper heat exchanger, 2 is the outlet of the upper heat exchanger, 3 is the inlet of the middle heat exchange tube, 4 is the outlet of the middle heat exchange tube, 5 is the inlet of the lower heat exchange tube, 6 is the outlet of the lower heat exchange tube, 7 is the outlet of desulfurization wastewater, 8 is the inlet of desulfurization wastewater, 9 is the sludge discharge port, 10 is the packing material of the clarifier, 11 is the flexible connecting pipe, 12 is the heat exchange tube, 13 is the upper heat exchanger, 14 is the lower heat exchanger, 15 is the temperature sensor, 16 is the pipe support, and 161 is the shock absorption device. Detailed Implementation

[0041] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. It should be noted that the terms "front," "rear," "left," "right," "up," and "down" used in the following description refer to directions in the accompanying drawings, and the terms "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0042] As shown in Figures 1-3, this embodiment of a high-efficiency clarification device for desulfurization wastewater includes a clarification tank body. The clarification tank body has an upper heat exchanger 13, a heat exchange tube 12, and a lower heat exchanger 14 arranged sequentially from top to bottom within its inner cavity. The bottom of the heat exchange tube 12 is connected to a pipe support 16, and the top is provided with clarification tank packing 10. The other end of the pipe support 16 is connected to the bottom of a sedimentation tank within the clarification tank body. The bottom of the sedimentation tank has a sludge discharge port 9. One end of the upper heat exchanger 13 is connected to the upper heat exchanger inlet 1, and the other end is connected to the upper heat exchanger outlet 2. One end of the heat exchange tube 12 is connected to the middle heat exchange tube inlet 3, and the other end is connected to the middle heat exchange tube outlet 4. One end of the lower heat exchanger 14 is connected to the lower heat exchange tube inlet 5, and the other end is connected to the lower heat exchange tube outlet 6. The front end of the clarification tank body is sequentially provided with a desulfurization wastewater outlet 7 and a desulfurization wastewater inlet 8.

[0043] The inlet 3 and outlet 4 of the central heat exchange tube are connected to the heat exchange tube 12 via flexible connecting pipes 11; the flexible connecting pipes 11 are steel wire braided pipes.

[0044] A shock-absorbing device 161 is installed between the pipe support 16 and the heat exchange tube 12; the shock-absorbing device 161 is a pneumatic damper.

[0045] The clarifier packing 10 is fixed to the heat exchange tube 12 by binding.

[0046] The upper heat exchanger 13, heat exchange tube 12 and lower heat exchanger 14 operate independently, and the heat exchange media of the three do not circulate with each other; the medium in the heat exchanger is concentrated brine from the desulfurization wastewater treatment process.

[0047] Temperature sensors 15 are arranged on the upper heat exchanger 13, the heat exchange tube 12, and the lower heat exchanger 14.

[0048] The process flow diagram of the equipment is shown in Figure 4. The desulfurization wastewater enters the high-efficiency clarification tank through the desulfurization wastewater inlet 8. Under the combined action of gravity and the clarification tank packing material 10, the suspended solids in the water gradually settle. The settled mud and water are discharged into the collection system through the mud discharge outlet 9. The clean water flows out from the desulfurization wastewater outlet 7 into the ultrafiltration device. After further purification by the ultrafiltration device, it enters the concentration device for concentration. The concentrated clean water is reused. The concentrated brine enters the upper heat exchanger 13, heat exchange tube 12 and lower heat exchanger 14 through the upper heat exchanger inlet 1, the middle heat exchange tube inlet 3 and the lower heat exchange tube inlet 5. Finally, it flows out from the upper heat exchanger outlet 2, the middle heat exchange tube outlet 4 and the lower heat exchange tube outlet 6 respectively and enters the evaporation device.

[0049] The flow rate is dynamically adjusted based on data from temperature sensor 15. The heat exchange medium flow rate is calculated using the following formula:

[0050]

[0051] Where G is the concentrated brine flow rate in each heat exchanger, in kg / h;

[0052] G1—Flow rate of desulfurization wastewater in each heat exchanger area, kg / h;

[0053] c1——Specific heat capacity of desulfurization wastewater, kJ / (kg·℃);

[0054] c—Specific heat capacity of concentrated brine, kJ / (kg·℃);

[0055] T1, T2 — Temperature changes of desulfurization wastewater before and after passing through each heat exchange zone, kJ / (kg·℃);

[0056] t1, t2 — Temperature changes of concentrated brine before and after passing through each heat exchange zone, kJ / (kg·℃);

[0057] The flow rate of the heat exchange medium in each zone's heat exchanger is automatically adjusted based on the temperature feedback from the temperature sensors in each zone as shown in the above formula.

[0058] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features.

Claims

1. A high-efficiency clarification device for desulfurization wastewater, characterized in that, The system includes a clarifier body, and the inner cavity of the clarifier body is provided with an upper heat exchanger (13), a heat exchange tube (12), and a lower heat exchanger (14) from top to bottom; the bottom of the heat exchange tube (12) is connected to a pipe support (16), and the top is provided with clarifier packing (10); the other end of the pipe support (16) is connected to the bottom of the sedimentation tank inside the clarifier body; the bottom of the sedimentation tank is provided with a sludge discharge port (9); one end of the upper heat exchanger (13) is connected to the upper heat exchange tube (14). The heat exchanger inlet (1) is connected to the upper heat exchanger outlet (2) at the other end; one end of the heat exchange tube (12) is connected to the middle heat exchange tube inlet (3) at the other end and to the middle heat exchange tube outlet (4) at the other end; one end of the lower heat exchanger (14) is connected to the lower heat exchange tube inlet (5) at the other end and to the lower heat exchange tube outlet (6) at the other end; wherein the front end of the clarification tank body is provided with a desulfurization wastewater outlet (7) and a desulfurization wastewater inlet (8) in sequence.

2. A high-efficiency clarifying device for desulfurization wastewater according to claim 1, characterized in that, The inlet (3) and outlet (4) of the central heat exchange tube are connected to the heat exchange tube (12) via flexible connecting pipe (11).

3. The high-efficiency clarification device for desulfurization wastewater according to claim 2, characterized in that, The flexible connecting pipe (11) is a steel wire braided pipe or a plastic hose.

4. The high-efficiency clarification device for desulfurization wastewater according to claim 1, characterized in that, A shock-absorbing device (161) is installed between the pipe support (16) and the heat exchange tube (12).

5. The high-efficiency clarification device for desulfurization wastewater according to claim 4, characterized in that, The shock absorption device (161) is a spring or a pneumatic damper.

6. The high-efficiency clarification device for desulfurization wastewater according to claim 1, characterized in that, The clarifier packing (10) is fixed to the heat exchange tube (12) by binding, welding or pressing.

7. The high-efficiency clarification device for desulfurization wastewater according to claim 1, characterized in that, The upper heat exchanger (13), heat exchange tube (12) and lower heat exchanger (14) operate independently, and the heat exchange media of the three do not flow between each other.

8. The high-efficiency clarification device for desulfurization wastewater according to claim 7, characterized in that, The medium in the heat exchanger is concentrated brine from the desulfurization wastewater treatment process, industrial wastewater, tap water, or other low-temperature media.

9. The high-efficiency clarification device for desulfurization wastewater according to claim 1, characterized in that, Temperature sensors (15) are arranged on the upper heat exchanger (13), heat exchange tube (12) and lower heat exchanger (14).

10. The high-efficiency clarification device for desulfurization wastewater according to claim 1, characterized in that, The packing material of the clarifier packing (10) is PP inclined plate, PVC inclined plate or steel plate.

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