Thermoelectric desulfurization system capable of recycling waste water

Abstract

The utility model provides a thermoelectric desulfurization system capable of recycling waste water, which comprises a desulfurization tower, an oxidation tower, a first waste water pipeline, a first control valve, a second waste water pipeline and a second control valve, the first end of the first waste water pipeline is communicated with a desulfurization spray header in the desulfurization tower, and the communicated position is higher than a smoke inlet of the desulfurization tower; the first control valve is arranged at the first end of the first wastewater pipeline, the first end of the second wastewater pipeline is communicated with the top of the oxidation tower, and the second control valve is arranged at the first end of the second wastewater pipeline; the second end of the first wastewater pipeline and the second end of the second wastewater pipeline are both used for being communicated with a low-COD wastewater pipeline of the integrated chemical device. According to the utility model, the low-COD wastewater of the integrated chemical device is used as the supplemented water of the desulfurization tower and the oxidation tower in the thermoelectric desulfurization system, so that the cyclic utilization rate of industrial wastewater is improved, and the sewage treatment cost is greatly reduced.

Description

Technical Field

[0001] This utility model relates to the technical field of chemical production, and in particular to a thermoelectric desulfurization system for wastewater reuse. Background Technology

[0002] Sulfur dioxide (SO2) is an atmospheric pollutant produced by coal combustion. Flue gas desulfurization is an effective and important means of controlling SO2 emissions, and it is currently mainly divided into calcium-based desulfurization and ammonia-based desulfurization processes. The ammonia-based desulfurization process uses an ammonia-containing solution to spray onto the flue gas, absorbing the sulfur dioxide and ultimately oxidizing it to ammonium sulfate. This process has low power and water consumption, uses widely available desulfurizing agents, and produces no wastewater, waste gas, or waste residue. The byproduct, ammonium sulfate, can be used to make sulfur-based fertilizers, making it a truly green and environmentally friendly technology without secondary pollution. Although the ammonia-based desulfurization process consumes significantly less water than the calcium-based process, taking only two 220-ton / hour steam-producing thermal power boiler desulfurization systems as an example, approximately 180,000 tons of fresh water are required annually as makeup water for the desulfurization system.

[0003] On the other hand, currently, integrated chemical plants produce low COD (Chemical Oxygen Demand) evaporative condensate. Most of the condensate wastewater is eventually discharged to wastewater treatment plants, which not only has the problem of low reuse rate, but also causes additional wastewater treatment costs.

[0004] Therefore, designing a novel desulfurization device that uses low-COD wastewater as makeup water for a thermal power system is essential for the chemical industry. Utility Model Content

[0005] To address the aforementioned problems in the prior art, this utility model provides a wastewater reuse thermoelectric desulfurization system, which improves the recycling rate of industrial wastewater and reduces wastewater treatment costs.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0007] In a first aspect, this utility model provides a wastewater reuse thermal desulfurization system, including a desulfurization tower, an oxidation tower, a first wastewater pipeline, a first control valve, a second wastewater pipeline, and a second control valve. The first end of the first wastewater pipeline is connected to a desulfurization spray head inside the desulfurization tower, and the height of the connection position is higher than the flue gas inlet of the desulfurization tower. The first control valve is located at the first end of the first wastewater pipeline. The first end of the second wastewater pipeline is connected to the top of the oxidation tower. The second control valve is located at the first end of the second wastewater pipeline.

[0008] The second end of both the first wastewater pipeline and the second wastewater pipeline is used to connect to the low-COD wastewater pipeline of the integrated chemical plant.

[0009] The beneficial effects of this invention are as follows: by using the low-COD wastewater from the integrated chemical plant as makeup water for the desulfurization tower and oxidation tower in the thermal power desulfurization system, the recycling rate of industrial wastewater is improved and the cost of sewage treatment is significantly reduced.

[0010] Optionally, it also includes a first flow transmitter, a first flow control valve, a second flow transmitter, a second flow control valve, and a wastewater main valve. One end of the wastewater main valve is connected to the second end of the first wastewater pipeline and the second end of the second wastewater pipeline, and the other end is used to connect to the low COD wastewater pipeline of the integrated chemical plant. The first flow transmitter and the first flow control valve are sequentially arranged on the first wastewater pipeline near the wastewater main valve, and the second flow transmitter and the second flow control valve are sequentially arranged on the second wastewater pipeline near the wastewater main valve.

[0011] Optionally, the bottom of the oxidation tower is connected to a first spray head located in the middle of the desulfurization tower via a first desulfurization water inlet pipeline. A desulfurization circulation pump is installed on the first desulfurization water inlet pipeline, and the top of the oxidation tower is also connected to a water replenishment pipeline connected to the fresh water main.

[0012] As can be seen from the above, when the flow of low COD wastewater stops or is insufficient, water is flexibly replenished to each water-using unit of the thermal power desulfurization system through the fresh water main pipe to ensure the normal operation of the thermal power desulfurization system.

[0013] Optionally, the first desulfurization inlet pipeline is connected to the second spray head located below the first spray head on the desulfurization tower via the second desulfurization inlet pipeline. The desulfurization tower is provided with a desulfurization water washing collection tank between the first spray head and the second spray head. The outlet of the desulfurization water washing collection tank is connected to the top of the oxidation tower via a return water pipeline.

[0014] Optionally, the system also includes a primary water washing tank and a secondary water washing tank. The top of the desulfurization tower is provided with a demister, a secondary water washing assembly, and a primary water washing assembly from top to bottom. The demister is connected to a process water tank containing fresh water. The secondary water washing assembly is circulatedly connected to the secondary water washing tank. The primary water washing assembly is circulatedly connected to the primary water washing tank.

[0015] Optionally, the secondary washing assembly is provided with a secondary spray head, a secondary packing layer and a secondary washing liquid collection tank in sequence from top to bottom; the primary washing assembly is provided with a primary spray head, a primary packing layer and a primary washing liquid collection tank in sequence from top to bottom; both the primary and secondary washing tanks are connected to the main fresh water pipe through a water supply line; the bottom of the primary washing tank is connected to the primary spray head through a first washing water inlet line; the primary washing liquid collection tank is connected to the top of the primary washing tank through a return water line; the bottom of the secondary washing tank is connected to the secondary spray head through a second washing water inlet line; and the secondary washing liquid collection tank is connected to the top of the secondary washing tank through a return water line.

[0016] A first water washing circulation pump is installed on the first water washing inlet pipeline, and a second water washing circulation pump is installed on the second water washing inlet pipeline.

[0017] Optionally, two demisters are spaced apart at the top of the desulfurization tower. A demisting spray head with a spray direction facing the demister is provided below the upper demister and above and below the lower demister. Each demisting spray head is connected to one end of a demisting circulation pump through a demisting pipeline. The other end of the demisting circulation pump is used to connect to a process water tank. A demisting control valve is provided on each demisting pipeline.

[0018] Optionally, the top of the desulfurization tower is provided with a flue pipe. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a wastewater reuse thermoelectric desulfurization system according to an embodiment of the present invention.

[0020] Explanation of reference numerals in the attached figures:

[0021] 1. Desulfurization tower; 2. Oxidation tower; 3. First wastewater pipeline; 4. First control valve; 5. Second wastewater pipeline; 6. Second control valve; 7. First flow transmitter; 8. First flow control valve; 9. Second flow transmitter; 10. Second flow control valve; 11. Wastewater main valve; 12. First desulfurization inlet pipeline; 13. First spray head; 14. Desulfurization circulating pump; 15. Makeup water pipeline; 16. Second desulfurization inlet pipeline; 17. Second spray head; 18. Desulfurization water washing collection tank; 19. Return water pipeline; 20. Primary water washing tank; 21. Secondary water washing tank; 22. 23. Demister; 24. Secondary spray head; 25. Secondary packing layer; 26. Secondary water washing collection tank; 27. Primary spray head; 28. Primary packing layer; 29. ​​Primary water washing collection tank; 30. First water washing inlet pipeline; 31. Second water washing inlet pipeline; 32. First water washing circulation pump; 33. Second water washing circulation pump; 34. Demister spray head; 35. Demister pipeline; 36. Demister circulation pump; 37. Demister control valve; 38. Exhaust pipe; 39. Inlet pipe; 40. Enrichment circulation pump; 41. Desulfurization discharge pump; 42. Oxidation fan; 43. Desulfurization spray head;

[0022] 100. Low COD wastewater pipeline. Detailed Implementation

[0023] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.

[0024] Example 1

[0025] Please refer to Figure 1 This embodiment provides a wastewater reuse thermoelectric desulfurization system, including a desulfurization tower 1, an oxidation tower 2, a first wastewater pipeline 3, a first control valve 4, a second wastewater pipeline 5, a second control valve 6, a first flow transmitter 7, a first flow control valve 8, a second flow transmitter 9, a second flow control valve 10, a wastewater main valve 11, a primary water washing tank 20, and a secondary water washing tank 21.

[0026] The first end of the first wastewater pipeline 3 is connected to the desulfurization spray head 42 inside the desulfurization tower 1, and the height of the connection position is higher than the flue gas inlet of the desulfurization tower 1. The first control valve 4 is installed on the first end of the first wastewater pipeline 3. The first end of the second wastewater pipeline 5 is connected to the top of the oxidation tower 2. The second control valve 6 is installed on the first end of the second wastewater pipeline 5. The second ends of the first wastewater pipeline 3 and the second ends of the second wastewater pipeline 5 are both used to connect to the low COD wastewater pipeline 100 of the integrated chemical plant.

[0027] One end of the wastewater main valve 11 is connected to the second end of the first wastewater pipeline 3 and the second end of the second wastewater pipeline 5, and the other end is used to connect to the low COD wastewater pipeline 100 of the integrated chemical plant. The first flow transmitter 7 and the first flow control valve 8 are sequentially installed on the first wastewater pipeline 3 near the wastewater main valve 11. The second flow transmitter 9 and the second flow control valve 10 are sequentially installed on the second wastewater pipeline 5 near the wastewater main valve 11.

[0028] The bottom of the oxidation tower 2 is connected to the first spray head 13 in the middle of the desulfurization tower 1 via the first desulfurization water inlet pipeline 12. A desulfurization circulation pump 14 is installed on the first desulfurization water inlet pipeline 12. The top of the oxidation tower 2 is also connected to a water replenishment pipeline 15 that is connected to the fresh water main.

[0029] The first desulfurization water inlet pipeline 12 is connected to the second spray head 17 located below the first spray head 13 on the desulfurization tower 1 via the second desulfurization water inlet pipeline 16. The desulfurization tower 1 is provided with a desulfurization water washing collection tank 18 between the first spray head 13 and the second spray head 17. The outlet of the desulfurization water washing collection tank 18 is connected to the top of the oxidation tower 2 via a return water pipeline 19.

[0030] The top of the desulfurization tower 1 is equipped with a demister 22, a secondary water washing assembly and a primary water washing assembly from top to bottom. The demister 22 is connected to a process water tank containing fresh water. The secondary water washing assembly is circulatedly connected to the secondary water washing tank 21. The primary water washing assembly is circulatedly connected to the primary water washing tank 20. Specifically, the secondary water washing assembly consists of a secondary spray head 23, a secondary packing layer 24, and a secondary water washing collection tank 25 arranged from top to bottom. The primary water washing assembly consists of a primary spray head 26, a primary packing layer 27, and a primary water washing collection tank 28 arranged from top to bottom. Both the primary water washing tank 20 and the secondary water washing tank 21 are connected to the main fresh water pipe through a water supply line 15. The bottom of the primary water washing tank 20 is connected to the primary spray head 26 through a first water washing inlet line 29. The primary water washing collection tank 28 is connected to the top of the primary water washing tank 20 through a return water line 19. The bottom of the secondary water washing tank 21 is connected to the secondary spray head 23 through a second water washing inlet line 30. The secondary water washing collection tank 25 is connected to the top of the secondary water washing tank 21 through a return water line 19. A first water washing circulation pump 31 is installed on the first water washing inlet line 29, and a second water washing circulation pump 32 is installed on the second water washing inlet line 30.

[0031] Among them, two demisters 22 are arranged at intervals on the top of the desulfurization tower 1. Below the upper demister 22 and above and below the lower demister 22, there is a demisting spray head 33 with the spray direction facing the demister 22. Each demisting spray head 33 is connected to one end of the demisting circulation pump 35 through the demisting pipeline 34. The other end of the demisting circulation pump 35 is used to connect to the process water tank. Each demisting pipeline 34 is equipped with a demisting control valve 36.

[0032] The desulfurization tower 1 is equipped with a flue gas pipe 37 at its top. Simultaneously, the bottom of the desulfurization tower 1 is equipped with a flue gas inlet pipe 38, a enrichment circulation pump 39, and a desulfurization discharge pump 40. The flue gas inlet pipe 38 is connected to the desulfurization tower 1 as the flue gas inlet. The enrichment circulation pump 39 performs self-circulation. The end of the desulfurization discharge pump 40 furthest from the desulfurization tower 1 is connected to an ammonium sulfate centrifugal drying system. Therefore, this embodiment uses an ammonia-based desulfurization system as an application example. In other embodiments, the desulfurization system of the desulfurization tower 1 can be other desulfurization devices.

[0033] The oxidation tower 2 is equipped with an oxidation blower 41 at its bottom, which is also connected to an ammonium sulfite pipeline and an ammonia water pipeline. Control valves are installed on the second desulfurization inlet water pipeline 16 and the ammonia water pipeline, and level valves are installed on the three water supply pipelines 15.

[0034] Among them, the low COD wastewater pipeline 100 of the integrated chemical plant includes, but is not limited to, high ammonia nitrogen wastewater after wet catalytic oxidation (CWAO) treatment of caprolactam waste liquid, evaporation condensate wastewater from ammonium sulfate unit and caprolactam unit, etc.

[0035] It should be noted that, based on this, existing detection technologies can be used to analyze the composition of the wastewater source. If the wastewater source is ammonium sulfate condensate wastewater or high-concentration ammonium sulfate wastewater, then the first wastewater pipeline 3 to desulfurization tower 1 should be selected. If the wastewater source is ammonia wastewater, evaporation tower condensate, sulfite wastewater, etc., then the second wastewater pipeline 5 to oxidation tower 2 should be selected. This maximizes the utilization of wastewater while minimizing its adverse effects on the desulfurization system.

[0036] Therefore, the working principle of this embodiment is explained as follows:

[0037] Fresh water from the plant's process water network enters the process water tank, primary wash tank 20, and secondary wash tank 21 under the control of the level control valve. It is then pumped out by the demister circulation pump 35, the first wash circulation pump 31, and the second wash circulation pump 32 to flush the demister 22 and replenish desulfurization water. There are two branches:

[0038] 1. First branch: The process water used to rinse the demister 22 falls into the secondary water washing collection tank 25 after rinsing the demister 22. It then merges with the circulating spray water of the secondary water washing section and flows into the secondary water washing tank 21 for recycling.

[0039] Among them, the demister 22 flushing pipeline is equipped with multiple flushing branch pipes.

[0040] 2. Second branch: Fresh water enters the primary water washing tank 20 and the secondary water washing tank 21 under the control of the liquid level valve to maintain the stability of the liquid level in the primary and secondary circulating water tanks.

[0041] 2.1 Secondary water circulation process

[0042] After collecting the scrubbing water from this stage in the secondary scrubbing collection tank 25, it flows by gravity into the secondary scrubbing tank 21. Then, it is pumped by the second scrubbing circulation pump 32 into the secondary spray head 23 for spraying. After being evenly distributed above the secondary packing layer 24, it enters the secondary packing layer 24 and then collects in the secondary scrubbing collection tank 25 before flowing into the secondary scrubbing tank 21. This completes the final scrubbing of the counter-rising flue gas, capturing SO2 and NH3 that escape with the airflow.

[0043] 2.2 Primary Water Circulation Process

[0044] After collecting the scrubbing water in the primary water collection tank 28, it flows by gravity into the primary water washing tank 20. Then, it is pumped by the first water washing circulation pump 31 into the primary spray head 26 for spraying. After being evenly distributed above the primary packing layer 27, it enters the primary packing layer 27 and then collects in the primary water collection tank 28 before flowing into the primary water washing tank 20. During the process of gradually flowing downwards after spraying, it comes into counter-current contact with the rising desulfurized flue gas, completing the scrubbing of the flue gas and capturing SO2 and NH3 that escape with the airflow.

[0045] 3. A new low-COD wastewater pipeline 100 from other integrated chemical plants is added to this system. It can be selected to supply either desulfurization tower 1 or oxidation tower 2 as needed, and the flow rates of the two wastewater pipelines can be adjusted according to the system's water replenishment requirements. When the integrated chemical plant shuts down or reduces its load, causing the low-COD wastewater pipeline 100 to stop supplying water or have insufficient flow, the fresh water main pipe will be used to replenish water to each water-using unit of the desulfurization system. The process is consistent with the original desulfurization system water replenishment process.

[0046] Therefore, this embodiment has the following advantages:

[0047] 1. This utility model uses low-COD wastewater from an integrated chemical plant as makeup water for a thermal power desulfurization system, which improves the recycling rate of industrial wastewater, significantly reduces wastewater treatment costs, and at the same time, the thermal power desulfurization system can save more than 70% of fresh water makeup water.

[0048] 2. The process of this utility model is easy to adjust, and the coordination between the fresh water main pipe and the wastewater pipeline can meet the flexible water replenishment needs of each water-using unit in the thermal power desulfurization system.

[0049] 3. This utility model has the advantages of simple process flow, small investment in modification, high efficiency, and safety and reliability.

[0050] In the description of this utility model, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0051] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.

[0052] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "beneath" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0053] In the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0054] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make modifications, alterations, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A wastewater reuse thermoelectric desulfurization system, characterized in that, The system includes a desulfurization tower, an oxidation tower, a first wastewater pipeline, a first control valve, a second wastewater pipeline, and a second control valve. The first end of the first wastewater pipeline is connected to a desulfurization spray head inside the desulfurization tower, and the height of the connection point is higher than the flue gas inlet of the desulfurization tower. The first control valve is located at the first end of the first wastewater pipeline. The first end of the second wastewater pipeline is connected to the top of the oxidation tower, and the second control valve is located at the first end of the second wastewater pipeline. The second end of both the first wastewater pipeline and the second wastewater pipeline is used to connect to the low-COD wastewater pipeline of the integrated chemical plant.

2. The wastewater reuse thermoelectric desulfurization system according to claim 1, characterized in that, It also includes a first flow transmitter, a first flow control valve, a second flow transmitter, a second flow control valve, and a wastewater main valve. One end of the wastewater main valve is connected to the second end of the first wastewater pipeline and the second end of the second wastewater pipeline, and the other end is used to connect to the low COD wastewater pipeline of the integrated chemical plant. The first flow transmitter and the first flow control valve are sequentially arranged on the first wastewater pipeline near the wastewater main valve, and the second flow transmitter and the second flow control valve are sequentially arranged on the second wastewater pipeline near the wastewater main valve.

3. The wastewater reuse thermoelectric desulfurization system according to claim 1, characterized in that, The bottom of the oxidation tower is connected to the first spray head located in the middle of the desulfurization tower via the first desulfurization water inlet pipeline. A desulfurization circulation pump is installed on the first desulfurization water inlet pipeline. The top of the oxidation tower is also connected to a water replenishment pipeline that is connected to the fresh water main pipe.

4. The wastewater reuse thermoelectric desulfurization system according to claim 3, characterized in that, The first desulfurization inlet water pipeline is connected to the second spray head located below the first spray head on the desulfurization tower via the second desulfurization inlet water pipeline. The desulfurization tower is provided with a desulfurization water washing collection tank between the first spray head and the second spray head. The outlet of the desulfurization water washing collection tank is connected to the top of the oxidation tower via a return water pipeline.

5. A wastewater reuse thermoelectric desulfurization system according to any one of claims 1 to 4, characterized in that, It also includes a primary water washing tank and a secondary water washing tank. The top of the desulfurization tower is provided with a demister, a secondary water washing assembly and a primary water washing assembly from top to bottom. The demister is connected to a process water tank containing fresh water. The secondary water washing assembly is circulatedly connected to the secondary water washing tank. The primary water washing assembly is circulatedly connected to the primary water washing tank.

6. The wastewater reuse thermoelectric desulfurization system according to claim 5, characterized in that, The secondary washing assembly consists of a secondary spray head, a secondary packing layer, and a secondary washing liquid collection tank arranged sequentially from top to bottom. The primary washing assembly consists of a primary spray head, a primary packing layer, and a primary washing liquid collection tank arranged sequentially from top to bottom. Both the primary and secondary washing tanks are connected to the main fresh water pipe via a water supply line. The bottom of the primary washing tank is connected to the primary spray head via a first washing water inlet line. The primary washing liquid collection tank is connected to the top of the primary washing tank via a return water line. The bottom of the secondary washing tank is connected to the secondary spray head via a second washing water inlet line. The secondary washing liquid collection tank is connected to the top of the secondary washing tank via a return water line. A first water washing circulation pump is installed on the first water washing inlet pipeline, and a second water washing circulation pump is installed on the second water washing inlet pipeline.

7. A wastewater reuse thermoelectric desulfurization system according to claim 5, characterized in that, Two demisters are spaced apart at the top of the desulfurization tower. A demisting spray head with a spray direction facing the demister is provided below the upper demister and above and below the lower demister. Each demisting spray head is connected to one end of a demisting circulation pump through a demisting pipeline. The other end of the demisting circulation pump is used to connect to a process water tank. A demisting control valve is provided on each demisting pipeline.

8. The wastewater reuse thermoelectric desulfurization system according to claim 1, characterized in that, The top of the desulfurization tower is equipped with a flue pipe.

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