Urea hydrolysis waste liquid recycling system

Abstract

The utility model discloses a urea hydrolysis waste liquid recycling system which comprises a blowdown main pipe, a urea waste liquid buffer tank, an ammonia gas leakage prevention device, a urea waste liquid conveying pipeline and a high-temperature spray gun, the urea waste liquid buffer tank is connected with a urea hydrolyzer through the blowdown main pipe, and the ammonia gas leakage prevention device is arranged on the urea waste liquid buffer tank. A heating coil is arranged in the bottom of the urea waste liquid buffer tank, a urea waste liquid conveying pipeline is connected with the urea waste liquid buffer tank and a high-temperature spray gun, a conveying pump is arranged on the urea waste liquid conveying pipeline, a compressed air conveying pipeline is connected to a pipeline between the conveying pump and the high-temperature spray gun, the high-temperature spray gun extends into a flue, and urea hydrolysis waste liquid is sprayed into the flue. And decomposing and recycling at high temperature. The urea waste liquid buffer tank disclosed by the utility model has the functions of heating, diluting and insulating, effectively prevents blockage, and realizes the recycling of urea waste liquid through the high-temperature spray gun.

Description

Technical Field

[0001] The utility model belongs to the technical field of wastewater treatment, and in particular relates to a urea hydrolysis waste liquid recycling system. Background Art

[0002] In recent years, coal-fired power plants have mostly switched to urea as a denitrification reducing agent, using urea hydrolysis to produce ammonia. However, impurities such as biuret produced during the operation of the urea hydrolysis ammonia production system cannot be discharged with the product gas. As the urea hydrolyzer operates over a long period of time, the concentration of impurities in the urea solution increases. Therefore, the hydrolyzer needs to regularly discharge waste liquid from the bottom, removing the deposited impurities along with it, creating the urea hydrolysis waste liquid. Currently, urea hydrolysis waste liquid is often treated by adding chemicals such as sodium hypochlorite. This treatment is costly, inefficient, time-consuming, and carries the risk of ammonia leakage and environmental pollution. Utility Model Content

[0003] In view of the above problems, the purpose of the present invention is to provide a urea hydrolysis waste liquid recycling system.

[0004] The specific technical solutions are as follows:

[0005] A urea hydrolysis waste liquid recycling system comprises a sewage main pipe, a urea waste liquid buffer tank, an ammonia leakage prevention device, a urea waste liquid conveying pipeline and a high-temperature spray gun. The urea waste liquid buffer tank is connected to a urea hydrolyzer through the sewage main pipe. The ammonia leakage prevention device is arranged on the urea waste liquid buffer tank. A heating coil is arranged in the bottom of the urea waste liquid buffer tank. A urea waste liquid conveying pipeline connects the urea waste liquid buffer tank and the high-temperature spray gun. A delivery pump is provided on the urea waste liquid conveying pipeline. A compressed air delivery pipeline is connected to the pipeline between the delivery pump and the high-temperature spray gun. The high-temperature spray gun extends into a flue. The urea hydrolysis waste liquid is sprayed into the flue and decomposed and reused with high temperature.

[0006] Furthermore, the ammonia leakage prevention device includes an intake valve, an exhaust pipe and a wastewater pool. The intake valve is arranged on the top of the urea waste liquid buffer tank. One end of the exhaust pipe is connected to the top of the urea waste liquid buffer tank, and the other end extends downward into the solution in the wastewater pool.

[0007] Furthermore, the top of the urea waste liquid buffer tank is also connected to a first desalted water pipeline for diluting the urea waste liquid. A stop valve is provided on the first desalted water pipeline, and a first ball valve and a first electromagnetic flowmeter are provided on the sewage main pipe.

[0008] Furthermore, a liquid level gauge is provided on the urea waste liquid buffer tank.

[0009] Furthermore, a filter is provided on the urea waste liquid delivery pipeline, and the filter is located between the urea waste liquid buffer tank and the delivery pump; the urea waste liquid delivery pipeline is also connected to a second desalted water pipeline for flushing the pipeline, and the second desalted water pipeline is located between the urea waste liquid buffer tank and the filter. Before the urea waste liquid stops back-spraying, the second desalted water pipeline is opened to flush the urea waste liquid delivery pipeline and the back-spray device to prevent them from being blocked.

[0010] Furthermore, pneumatic valves are respectively provided on the second desalted water pipeline, the compressed air delivery pipeline, and the pipeline connecting the filter and the urea waste liquid buffer tank.

[0011] Furthermore, the bottom of the urea waste liquid buffer tank is also connected to a bottom sewage pipe, and the bottom sewage pipe is connected to the exhaust pipeline.

[0012] Furthermore, a check valve and a second ball valve are provided on the pipeline connecting the delivery pump and the high-temperature spray gun, a second electromagnetic flowmeter is provided on the connecting pipeline between the filter and the delivery pump, and a third ball valve is provided on the connecting pipeline between the filter and the urea waste liquid buffer tank; the urea waste liquid delivery pipeline is provided with pipeline heating.

[0013] The high temperature spray gun is made of high temperature resistant and corrosion resistant materials, the nozzle is made of 310 stainless steel, and the nozzle is made of Hastelloy.

[0014] The beneficial effects of the present invention are:

[0015] 1) The urea waste liquid buffer tank of the utility model has heating, heat preservation and dilution functions, mainly to reduce the urea mass ratio in the waste liquid, ensure the urea waste liquid temperature at 40℃-60℃, reduce the precipitation of urea crystals and other by-product crystals in the urea waste liquid, and reduce the blockage of various parts of the recycling device;

[0016] 2) The urea waste liquid buffer tank of the present invention is equipped with electromagnetic flowmeters before and after, which can help monitor the urea waste liquid reuse ratio. The urea waste liquid buffer tank is equipped with bottom sewage discharge, top liquid seal exhaust and top-mounted air intake valve to reduce the risk of ammonia in the urea hydrolysis waste liquid leaking into the environment and causing pollution;

[0017] 3) The urea waste liquid buffer tank of the utility model is equipped with a liquid level gauge and a pneumatic valve at the outlet, which can collect the intermittently discharged urea waste liquid and automatically transport it to the flue for back-spraying when it reaches the specified liquid level. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the utility model.

[0019] In the figure: 1. sewage main pipe; 2. urea waste liquid buffer tank; 3. urea waste liquid delivery pipeline; 4. high-temperature spray gun; 5. heating coil; 6. delivery pump; 7. compressed air delivery pipeline; 8. flue; 9. suction valve; 10. exhaust pipeline; 11. wastewater tank; 12. first desalted water pipeline; 13. stop valve; 14. first ball valve; 15. first electromagnetic flowmeter; 16. liquid level gauge; 17. filter; 18. second desalted water pipeline; 19. pneumatic valve; 20. bottom sewage pipe; 21. check valve; 22. second ball valve; 23. second electromagnetic flowmeter; 24. third ball valve. DETAILED DESCRIPTION

[0020] The present invention will be further described below with reference to the accompanying drawings, but the protection scope of the present invention is not limited thereto.

[0021] like Figure 1 As shown, a urea hydrolysis waste liquid recycling system includes a sewage main pipe 1, a urea waste liquid buffer tank 2, a urea waste liquid conveying pipeline 3, a high-temperature spray gun 4, a heating coil 5, a conveying pump 6, a compressed air conveying pipeline 7, a flue 8, an exhaust pipeline 10, a wastewater tank 11, a first desalted water pipeline 12, a filter 17, a second desalted water pipeline 18 and a bottom sewage pipe 20. The urea waste liquid buffer tank 2 is connected to the urea hydrolyzer through the sewage main pipe 1. The sewage main pipe 1 is provided with a first ball valve 14 and a first electromagnetic flowmeter 15. The bottom of the urea waste liquid buffer tank 2 is provided with a heating coil 5. The intake valve 9 is provided at the top of the urea waste liquid buffer tank 2. The top of the urea waste liquid buffer tank 2 is also connected to the first desalted water pipeline 12 for diluting the urea waste liquid. The first desalted water pipeline 12 is provided with a stop valve 13. The urea waste liquid buffer tank 2 is provided with a liquid level gauge 16. One end of the exhaust pipeline 10 is connected to the urea waste liquid buffer tank 2. Above the flushing tank 2, the other end extends downward into the solution in the wastewater pool 11. The bottom of the urea waste liquid buffer tank 2 is also connected to a bottom drain pipe 20, which merges with the exhaust pipe 10. The urea waste liquid conveying pipeline 3 connects the urea waste liquid buffer tank 2 and the high-temperature spray gun 4. The high-temperature spray gun 4 extends into the flue 8. Starting from the urea waste liquid buffer tank 2, the urea waste liquid conveying pipeline 3 is sequentially provided with a third ball valve 24, a pneumatic valve 19, a filter 17, a second electromagnetic flowmeter 23, a delivery pump 6, a check valve 21 and a second ball valve 22. The pipeline between the pneumatic valve 19 and the third ball valve 24 is also connected to the second desalted water pipeline 18, and the pipeline between the second ball valve 22 and the high-temperature spray gun 4 is connected to a compressed air delivery pipeline 7. The second desalted water pipeline 18 and the compressed air delivery pipeline 7 are respectively provided with a pneumatic valve 19; the urea waste liquid conveying pipeline 3 is provided with pipeline heating.

[0022] The urea hydrolysis waste liquid is discharged from the sewage main pipe 1 to the urea waste liquid buffer tank 2. During the process, the urea hydrolysis waste liquid releases temperature and pressure, and ammonia is released. It is discharged from the exhaust pipe 10 to the wastewater pool 11. During this period, the stop valve 13 of the first desalted water pipe 12 can be selectively opened to dilute the urea hydrolysis waste liquid in the urea waste liquid buffer tank 2. When the urea hydrolysis waste liquid is discharged to the specified liquid level, the heating coil 5 is turned on to maintain the temperature of the urea hydrolysis waste liquid at 40-60°C, and the pneumatic valve 19 on the urea waste liquid conveying pipeline 3 and the compressed air conveying pipeline 7 is opened to start urea hydrolysis. The urea hydrolysis waste liquid is transported, after being filtered by the filter 17, by the delivery pump 6 to the high-temperature spray gun 4. The high-temperature spray gun 4 sprays the urea hydrolysis waste liquid into the flue 8 under the pressure of compressed air and the delivery pump 6. The high-temperature decomposition produces ammonia and carbon dioxide, which participate in the flue gas denitrification reaction and realize the recycling of the urea hydrolysis waste liquid. During the process, the recycling rate of the urea hydrolysis waste liquid can be evaluated by the first electromagnetic flowmeter 15 and the second electromagnetic flowmeter 23. When the back spray is about to stop, the second desalted water pipeline 18 is opened to flush the urea waste liquid delivery pipeline 3.

Claims

1. A urea hydrolysis waste liquid recycling system, characterized in that: The invention comprises a sewage main pipe (1), a urea waste liquid buffer tank (2), an ammonia leakage prevention device, a urea waste liquid conveying pipeline (3) and a high-temperature spray gun (4). The urea waste liquid buffer tank (2) is connected to the urea hydrolyzer through the sewage main pipe (1). The ammonia leakage prevention device is arranged on the urea waste liquid buffer tank (2). A heating coil (5) is arranged in the bottom of the urea waste liquid buffer tank (2). The urea waste liquid conveying pipeline (3) connects the urea waste liquid buffer tank (2) and the high-temperature spray gun (4). A conveying pump (6) is arranged on the urea waste liquid conveying pipeline (3). A compressed air conveying pipeline (7) is connected to the pipeline between the conveying pump (6) and the high-temperature spray gun (4). The high-temperature spray gun (4) extends into a flue (8). The urea hydrolysis waste liquid is sprayed into the flue (8) and is decomposed and reused at high temperature.

2. A urea hydrolysis waste liquid recycling system according to claim 1, characterized in that: The ammonia leakage prevention device comprises an air intake valve (9), an exhaust pipe (10) and a wastewater tank (11). The air intake valve (9) is arranged on the top of the urea waste liquid buffer tank (2). One end of the exhaust pipe (10) is connected to the top of the urea waste liquid buffer tank (2), and the other end extends downward into the solution in the wastewater tank (11).

3. A urea hydrolysis waste liquid recycling system as claimed in claim 2, characterized in that: The top of the urea waste liquid buffer tank (2) is also connected to a first desalted water pipeline (12) for diluting the urea waste liquid. A stop valve (13) is provided on the first desalted water pipeline (12). A first ball valve (14) and a first electromagnetic flowmeter (15) are provided on the sewage main pipe (1).

4. A urea hydrolysis waste liquid recycling system as claimed in claim 3, characterized in that: A liquid level gauge (16) is provided on the urea waste liquid buffer tank (2).

5. A urea hydrolysis waste liquid recycling system as claimed in claim 4, characterized in that: The urea waste liquid delivery pipeline (3) is further provided with a filter (17), which is located between the urea waste liquid buffer tank (2) and the delivery pump (6); the urea waste liquid delivery pipeline (3) is further connected to a second desalted water pipeline (18) for flushing the pipeline, which is located between the urea waste liquid buffer tank (2) and the filter (17).

6. A urea hydrolysis waste liquid recycling system as claimed in claim 5, characterized in that: Pneumatic valves (19) are respectively provided on the second desalted water pipeline (18), the compressed air delivery pipeline (7), and the pipeline connecting the filter (17) and the urea waste liquid buffer tank (2).

7. A urea hydrolysis waste liquid recycling system according to claim 6, characterized in that: The bottom of the urea waste liquid buffer tank (2) is also connected to a bottom sewage pipe (20), and the bottom sewage pipe (20) is connected to the exhaust pipeline (10).

8. A urea hydrolysis waste liquid recycling system as claimed in claim 7, characterized in that: A check valve (21) and a second ball valve (22) are provided on the pipeline connecting the delivery pump (6) and the high-temperature spray gun (4); a second electromagnetic flowmeter (23) is provided on the pipeline connecting the filter (17) and the delivery pump (6); and a third ball valve (24) is provided on the pipeline connecting the filter (17) and the urea waste liquid buffer tank (2); and a pipeline heating device is provided on the urea waste liquid delivery pipeline (3).

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