Desulfurization waste liquid classification treatment and recycling system

Abstract

The utility model belongs to the technical field of desulfurization waste liquid treatment, and specifically relates to a desulfurization waste liquid graded treatment and recycling system. It includes a desulfurization tower, a regulating tank, an inclined plate sedimentation tank, an ultrafiltration device and a reverse osmosis device connected in sequence. The clean water outlet of the reverse osmosis device is connected to a recycling water tank, and the outlet of the recycling water tank is connected to the spray system of the desulfurization tower through a pipeline; the concentrated water outlet of the reverse osmosis device is connected to a heat exchanger and an evaporation crystallizer in sequence, and the secondary steam outlet of the evaporation crystallizer is connected to the heat exchanger through a pipeline, and the heat exchanger outlet is connected to the recycling water tank through a pipeline, and the sludge outlet of the inclined plate sedimentation tank is connected to a plate and frame filter press. The system treats the desulfurization tower waste liquid by graded treatment, effectively separates fresh water for recycling, and precipitates crystallized salt for graded recovery, greatly reducing fresh water consumption and improving resource utilization; at the same time, the secondary steam is used to preheat the reverse osmosis concentrated water to realize heat energy circulation, which reduces energy consumption and conforms to the concept of green environmental protection.

Description

Technical Field

[0001] The utility model belongs to the technical field of desulfurization waste liquid treatment, and specifically relates to a desulfurization waste liquid classification treatment and circulation reuse system. Background Art

[0002] In industrial production processes such as coal-fired power plants, wet desulfurization technology is widely used, which mainly removes sulfur dioxide from flue gas through processes such as limestone-gypsum method. However, this process will produce a large amount of desulfurization waste liquid, which has complex components and contains heavy metal ions, suspended matter, soluble salts (such as chlorides, sulfates, etc.) and organic matter. If it is discharged directly, it will cause serious pollution to water bodies, soil and other environments, and endanger the ecosystem and human health.

[0003] At present, there are many methods for treating desulfurization wastewater. Although the traditional chemical precipitation method can remove some heavy metal ions, the quality of the treated water is difficult to meet the reuse standards, and a large amount of chemical sludge will be produced, and the subsequent disposal cost is high. The biological treatment method has a long treatment cycle, strict requirements on the treatment environment, and the treatment effect is easily affected by fluctuations in water quality and water volume, making it difficult to operate stably. In addition, some simple filtration treatment methods can only remove large suspended particles in the wastewater, and cannot effectively remove soluble pollutants, and cannot achieve deep treatment and recycling of desulfurization wastewater.

[0004] With increasingly stringent environmental protection requirements, the treatment of desulfurization waste liquid must not only meet the emission standards, but also achieve resource recycling to reduce dependence on fresh water resources and reduce waste liquid emissions. Therefore, it is of great significance to develop an efficient, economical and sustainable desulfurization waste liquid classification treatment and recycling system. Utility Model Content

[0005] In view of the above deficiencies in the prior art, the purpose of the utility model is to provide a desulfurization waste liquid classification treatment and recycling system, which can effectively separate fresh water for recycling and precipitate crystalline salt for classification recovery by classifying the desulfurization tower waste liquid, greatly reduce fresh water consumption and improve resource utilization; at the same time, secondary steam is used to preheat reverse osmosis concentrated water to realize heat energy circulation, reduce energy consumption, and comply with the concept of green environmental protection.

[0006] The utility model is realized by adopting the following technical solutions:

[0007] The desulfurization waste liquid classification treatment and recycling reuse system comprises a desulfurization tower, a regulating tank, an inclined plate sedimentation tank, an ultrafiltration device and a reverse osmosis device which are connected in sequence. The clean water outlet of the reverse osmosis device is connected to a recycling water tank, and the outlet of the recycling water tank is connected to the spray system of the desulfurization tower through a pipeline; the concentrated water outlet of the reverse osmosis device is connected to a heat exchanger and an evaporation crystallizer in sequence, the crystallized salt outlet of the evaporation crystallizer is connected to a crystallized salt bin, the secondary steam outlet of the evaporation crystallizer is connected to the shell side inlet of the heat exchanger through a pipeline, the shell side outlet of the heat exchanger is connected to the recycling water tank through a pipeline, and the sludge outlet of the inclined plate sedimentation tank is connected to a plate and frame filter press through a pipeline.

[0008] The regulating tank is connected with a lime milk dosing pipeline and a flocculant dosing pipeline.

[0009] A vibration screening device is provided in the crystallized salt warehouse.

[0010] A sludge pump is provided on the pipeline between the sludge outlet of the inclined plate sedimentation tank and the plate and frame filter press.

[0011] A metering pump is provided on the pipeline between the recycled water tank and the spraying system of the desulfurization tower.

[0012] A safety filter is also arranged between the ultrafiltration device and the reverse osmosis device.

[0013] The working principle of the desulfurization waste liquid classification treatment and recycling system is as follows:

[0014] The waste liquid generated by the desulfurization tower first enters the regulating tank, and lime milk is added through the lime milk dosing pipeline to adjust the pH value of the waste liquid, neutralize acidic substances and precipitate some heavy metals; at the same time, flocculants are added through the flocculant dosing pipeline to promote the coagulation of suspended matter and colloidal substances to form flocs that are easy to precipitate. The regulated waste liquid enters the inclined plate sedimentation tank, and the inclined plate structure is used to accelerate the solid-liquid separation. The supernatant enters the subsequent deep treatment unit, and the bottom sludge is transported to the plate and frame filter press by the sludge pump. After being filtered into mud cakes, it is transported and disposed of to achieve sludge reduction. The supernatant of the inclined plate sedimentation tank passes through the ultrafiltration device and the security filter in turn to intercept tiny suspended matter, colloids and macromolecular organic matter to ensure that the water quality meets the reverse osmosis membrane water inlet requirements. The wastewater then enters the reverse osmosis device, and high-pressure drive is used to achieve efficient separation of water and soluble salts. The produced fresh water (clean water) enters the reuse water tank and is accurately transported to the desulfurization tower spray system for recycling by the metering pump to reduce fresh water consumption.

[0015] The concentrated water produced by reverse osmosis is preheated in the heat exchanger tube and then enters the evaporation crystallizer, where the heat energy is used to evaporate the water and precipitate crystallized salt (including sodium sulfate and sodium chloride). The crystallized salt is graded and screened by a vibrating screening device and stored in a crystallization salt warehouse to achieve salt resource recovery. The secondary steam generated by the evaporation crystallizer enters the shell side of the heat exchanger and exchanges heat with the concentrated water of reverse osmosis. The condensed water generated after the heat exchange is collected in the recycling water tank, and the heat energy can be recycled to reduce the energy consumption of the system.

[0016] Compared with the prior art, the beneficial effects of the utility model are as follows:

[0017] (1) The desulfurization waste liquid classification treatment and recycling system described in the utility model, through the classification treatment of the desulfurization tower waste liquid, not only effectively separates fresh water for the desulfurization tower to recycle, greatly reducing the consumption of fresh water resources, but also can precipitate crystallized salt from the concentrated water, and realize the classification recovery of salts through the vibration screening device, thereby improving the comprehensive utilization rate of resources;

[0018] (2) The desulfurization waste liquid classification treatment and recycling system described in the utility model uses the secondary steam generated by the evaporation crystallizer to preheat the reverse osmosis concentrated water, realizing the recycling of heat energy and significantly reducing energy consumption. At the same time, the coordinated use of the inclined plate sedimentation tank and the plate and frame filter press effectively reduces the amount of sludge and reduces the cost of sludge treatment and disposal, which is in line with the concept of green environmental protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the desulfurization waste liquid classification treatment and recycling system described in the utility model;

[0020] In the figure: 1. Desulfurization tower; 2. Equalization tank; 3. Inclined plate sedimentation tank; 4. Ultrafiltration device; 5. Reverse osmosis device; 6. Recycled water tank; 7. Spraying system; 8. Heat exchanger; 9. Evaporation crystallizer; 10. Crystallization salt warehouse; 11. Plate and frame filter press; 12. Lime milk dosing pipeline; 13. Flocculant dosing pipeline; 14. Vibration screening device; 15. Sludge pump; 16. Metering pump; 17. Security filter. DETAILED DESCRIPTION

[0021] In order to make the purpose and technical solution of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings.

[0022] Example 1

[0023] like Figure 1As shown, the desulfurization waste liquid classification treatment and recycling system comprises a desulfurization tower 1, a regulating tank 2, an inclined plate sedimentation tank 3, an ultrafiltration device 4 and a reverse osmosis device 5 which are connected in sequence, the clean water outlet of the reverse osmosis device 5 is connected to a recycling water tank 6, and the outlet of the recycling water tank 6 is connected to the spray system 7 of the desulfurization tower 1 through a pipeline; the concentrated water outlet of the reverse osmosis device 5 is connected to a heat exchanger 8 and an evaporation crystallizer 9 in sequence, the crystallized salt outlet of the evaporation crystallizer 9 is connected to a crystallized salt warehouse 10, the secondary steam outlet of the evaporation crystallizer 9 is connected to the shell side inlet of the heat exchanger 8 through a pipeline, the shell side outlet of the heat exchanger 8 is connected to the recycling water tank 6 through a pipeline, and the sludge outlet of the inclined plate sedimentation tank 3 is connected to a plate and frame filter press 11 through a pipeline.

[0024] The regulating tank 2 is connected with a lime milk dosing pipeline 12 and a flocculant dosing pipeline 13 .

[0025] The crystallized salt warehouse 10 is provided with a vibration screening device 14 .

[0026] A sludge pump 15 is provided on the pipeline between the sludge outlet of the inclined plate sedimentation tank 3 and the plate and frame filter press 11 .

[0027] A metering pump 16 is provided on the pipeline between the recycled water tank 6 and the spray system 7 of the desulfurization tower 1 .

[0028] A safety filter 17 is also provided between the ultrafiltration device 4 and the reverse osmosis device 5 .

[0029] When working, the specific steps are as follows:

[0030] The waste liquid generated during the operation of the desulfurization tower 1 is introduced into the regulating tank 2. In the regulating tank 2, lime milk is added through the lime milk dosing pipeline 12 to adjust the pH value of the waste liquid to a suitable range. At the same time, the neutralization effect of the lime milk is utilized to effectively precipitate the acidic substances and some heavy metal ions in the waste liquid, thereby improving the subsequent treatment effect of the waste liquid. At the same time, flocculants are added to the regulating tank 2 through the flocculant dosing pipeline 13 to promote the rapid coagulation of suspended matter and colloidal substances in the waste liquid into larger flocs, which is convenient for subsequent solid-liquid separation.

[0031] The waste liquid treated in the regulating tank 2 then flows into the inclined plate sedimentation tank 3. The unique inclined plate structure is used to accelerate the settling speed of solid particles in the waste liquid and achieve efficient solid-liquid separation. The sludge deposited at the bottom of the inclined plate sedimentation tank 3 is pumped to the plate-frame filter press 11 by the sludge pump 15. In the plate-frame filter press 11, the sludge is filtered under high pressure to form a mud cake with a low water content. These mud cakes are safely transported out for final disposal, thereby achieving sludge reduction treatment.

[0032] The supernatant produced by the inclined plate sedimentation tank 3 enters the ultrafiltration device 4 and the security filter 17. The precise membrane structure of the ultrafiltration device 4 effectively intercepts the tiny suspended solids, colloids and macromolecular organic matter in the supernatant, further improving the water quality. The security filter 17 acts as an additional barrier to ensure that the water quality entering the reverse osmosis device 5 meets its strict water inlet requirements.

[0033] Subsequently, the water treated by ultrafiltration and security filtration enters the reverse osmosis device 5. In the reverse osmosis device 5, by applying a high-pressure driving force, efficient separation of water and soluble salts is achieved. The reverse osmosis membrane only allows water molecules to pass through, while most of the soluble salts are retained on the concentrated water side. The produced fresh water (i.e., clean water) is collected in the reuse water tank 6.

[0034] At the same time, the concentrated water produced by the reverse osmosis device 5 is introduced into the heat exchanger 8 for preheating. The preheated concentrated water enters the evaporation crystallizer 9, and the water therein is evaporated by heat energy, thereby precipitating crystallized salt (mainly including sodium sulfate, sodium chloride, etc.). These crystallized salts are graded and screened by the vibration screening device 14 and stored in the crystallized salt warehouse 10, realizing the effective recovery of salt resources.

[0035] The secondary steam generated by the evaporation crystallizer 9 during the evaporation process is sent to the shell side of the heat exchanger 8 to exchange heat with the reverse osmosis concentrated water. The condensed water generated after the heat exchange is also introduced into the recycling water tank 6, realizing the recycling of heat energy and significantly reducing the energy consumption of the system.

[0036] Finally, the clean water in the recycling water tank 6 is accurately transported to the spray system 7 of the desulfurization tower 1 through the metering pump 16, realizing the recycling of waste liquid and effectively reducing the consumption of fresh water resources. The working process of the whole system forms a closed-loop circulation system, which not only realizes the efficient treatment of waste liquid, but also realizes the maximum recovery and utilization of resources.

Claims

1. A desulfurization waste liquid classification treatment and recycling system, characterized in that: The invention comprises a desulfurization tower (1), a regulating tank (2), an inclined plate sedimentation tank (3), an ultrafiltration device (4) and a reverse osmosis device (5) which are connected in sequence. The clean water outlet of the reverse osmosis device (5) is connected to a recycling water tank (6), and the outlet of the recycling water tank (6) is connected to a spray system (7) of the desulfurization tower (1) through a pipeline. The concentrated water outlet of the reverse osmosis device (5) is connected to a heat exchanger (8) and an evaporation crystallizer (9) in sequence. The crystallized salt outlet of the evaporation crystallizer (9) is connected to a crystallized salt bin (10). The secondary steam outlet of the evaporation crystallizer (9) is connected to the shell side inlet of the heat exchanger (8) through a pipeline. The shell side outlet of the heat exchanger (8) is connected to the recycling water tank (6) through a pipeline. The sludge outlet of the inclined plate sedimentation tank (3) is connected to a plate and frame filter press (11) through a pipeline.

2. The desulfurization waste liquid classification treatment and recycling system according to claim 1 is characterized in that: The regulating tank (2) is connected to a lime milk dosing pipeline (12) and a flocculant dosing pipeline (13).

3. The desulfurization waste liquid classification treatment and recycling system according to claim 1 is characterized in that: The crystallized salt warehouse (10) is provided with a vibration screening device (14).

4. The desulfurization waste liquid classification treatment and recycling system according to claim 1 is characterized in that: A sludge pump (15) is provided on the pipeline between the sludge outlet of the inclined plate sedimentation tank (3) and the plate and frame filter press (11).

5. The desulfurization waste liquid classification treatment and recycling system according to claim 1 is characterized in that: A metering pump (16) is provided on the pipeline between the recycled water tank (6) and the spray system (7) of the desulfurization tower (1).

6. The desulfurization waste liquid classification treatment and recycling system according to claim 1 is characterized in that: A safety filter (17) is also provided between the ultrafiltration device (4) and the reverse osmosis device (5).

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