Method and apparatus for control of reflux ammonia in an aqueous urea plant

Abstract

The present application relates to the technical fields of water solution urea flow ammonia control device, and discloses a water solution urea device backflow ammonia control method and device, which comprises a supporting shaft, the surface of the supporting shaft is slidably connected with a sealing disc, and the surface of the sealing disc is fixedly connected with a force telescopic rod.The present application sets a backflow mechanism, then extracts the inside of the liquid ammonia tank through the ammonia booster pump, so as to achieve the circulation effect, which can effectively return the gas pressure backflow in the inside of the first absorption tower to the inside of the backflow pipe one and the pressure relief cylinder, and finally return the gas pressure backflow to the inside of the liquid ammonia tank through the backflow pipe two, so as to achieve the effect of relieving the pressure in the inside of the first absorption tower, thereby solving the problems of unstable opening degree of the valve and unstable temperature in the inside of the first absorption tower caused by excessive gas pressure in the inside of the first absorption tower, and after pressure backflow and pressure relief, the gas pressure backflow is small, thereby solving the problem of ammonia booster pump failure.

Description

Technical Field

[0001] This invention relates to the technical field of aqueous urea flow ammonia control equipment, specifically to a method and apparatus for controlling the reflux of ammonia in an aqueous urea plant. Background Technology

[0002] The aqueous urea unit is used to produce an aqueous urea solution with a concentration of 32.5%. It is mainly used to meet the exhaust gas treatment requirements of the China IV emission standard for heavy-duty diesel vehicles. The urea solution is injected into the flue through the SCR system to achieve nitrogen oxide reduction.

[0003] In a urea production unit using the aqueous solution full-circulation method, the reflux ammonia in the first-stage absorption tower is controlled by an ammonia booster pump and then by a regulating valve. The ammonia booster pump is a canned pump. Because it continuously supplies gas pressure to the inside of the first-stage gas tower, the gas pressure inside the first-stage gas tower increases. During the gas pressure reflux, the ammonia booster pump has a high failure rate during operation, and the valve control of the reflux ammonia opening is unstable. At the same time, it also causes the gas phase temperature of the first-stage absorption tower to be unstable. Summary of the Invention

[0004] The purpose of this invention is to provide a method and apparatus for controlling the reflux of ammonia in an aqueous urea plant, so as to solve the problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution:

[0006] This invention relates to a method and apparatus for controlling the reflux of ammonia in an aqueous urea plant, comprising a base, on the surface of which a support ring and a support frame are fixedly connected, an absorption tower section is fixedly connected to the inner wall of the support frame, and a gas phase output pipe is fixedly connected to the top of the absorption tower section; and further comprising:

[0007] An ammonia storage mechanism, the ammonia storage mechanism including a drain pipe, the surface of which is provided with a one-way valve;

[0008] The testing mechanism includes a liquid inlet pipe, and a second solenoid valve is provided on the surface of the liquid inlet pipe.

[0009] A reflux mechanism includes a support shaft, a sealing disc is slidably connected to the surface of the support shaft, and a force-bearing telescopic rod is fixedly connected to the surface of the sealing disc.

[0010] Furthermore, the end of the output pipe is connected to the top of a section of the inner wall of the absorption tower, and the bottom of the support ring and the support frame are both fixedly connected to the surface of the base.

[0011] Furthermore, the ammonia storage mechanism includes an ammonia filling pipe, and the surface of the ammonia filling pipe is provided with a one-way valve and a two-way valve. The end of the ammonia filling pipe is fixedly connected to a liquid ammonia tank.

[0012] Furthermore, the surface of the liquid ammonia adding pipe is fixedly connected to the inside of the support ring, the bottom of the liquid ammonia tank is fixedly connected to the surface of the base, the end of the drain pipe is fixedly connected to the surface of the liquid ammonia adding pipe, and the end of the liquid ammonia adding pipe is in communication with the inner wall of the liquid ammonia tank.

[0013] Furthermore, the detection mechanism includes an ammonia booster pump, the output end of which is fixedly connected to a liquid extraction pipe, a solenoid valve is provided on the surface of the liquid extraction pipe, and a concentration detector and a temperature detector are provided on the surface of the gas phase output pipe.

[0014] Furthermore, the end of the inlet pipe is fixedly connected to the output end of the ammonia booster pump, the end of the suction pipe away from the ammonia booster pump is fixedly connected to the top of the liquid ammonia tank, the bottom of the ammonia booster pump is fixedly connected to the surface of the base, and the end of the drain pipe away from the liquid ammonia adding pipe is fixedly connected to the surface of the inlet pipe.

[0015] Furthermore, the reflux mechanism includes a first reflux pipe, with a pressure relief cylinder fixedly connected to the end of the first reflux pipe. A sealing ring and a filter disc are fixedly connected to the inner wall of the pressure relief cylinder, and a second reflux pipe is fixedly connected to the end of the pressure relief cylinder away from the first reflux pipe.

[0016] Furthermore, the end of the first reflux pipe away from the pressure relief cylinder is fixedly connected to the surface of the inlet pipe, the surface of the filter disc is fixedly connected to the end of the sealing disc, the end of the force-bearing telescopic rod away from the sealing disc is fixedly connected to the surface of the filter disc, and the end of the second reflux pipe away from the pressure relief cylinder is fixedly connected to the surface of the liquid ammonia tank.

[0017] Furthermore, the method for controlling the reflux of ammonia in an aqueous urea plant includes the following steps:

[0018] S1: While liquid ammonia is being transported inside the liquid ammonia supply pipe, it will pass through check valve two. At this time, check valve two is activated again to prevent the liquid ammonia inside the liquid ammonia supply pipe from flowing back into the drain pipe. Finally, the liquid ammonia is transported to the liquid ammonia tank. The setting of check valve one, check valve two and check valve three effectively achieves the function of limiting the flow of liquid ammonia and preventing backflow.

[0019] S2: When liquid ammonia enters the first-stage absorption tower, the concentration detector is energized to detect the concentration of liquid ammonia inside the first-stage absorption tower. Then, the temperature detector is energized to detect the temperature of liquid ammonia inside the first-stage absorption tower. The concentration and temperature of liquid ammonia inside the first-stage absorption tower can be effectively detected in real time through the temperature detector and the concentration detector.

[0020] S3: At this time, the outer wall of the sealing disc will separate from the inner wall of the sealing ring. When the sealing disc slides, it will push the force-retracting telescopic rod to squeeze, causing the force-retracting telescopic rod to retract towards the filter disc. Since the sealing disc separates from the sealing ring, the air pressure will enter the interior of the return pipe 2 through the filter disc, and the air pressure can be filtered through the filter disc.

[0021] S4: When the gas pressure enters the interior of return pipe two, it enters the interior of the liquid ammonia tank. Then, the ammonia booster pump extracts the gas pressure from the interior of the liquid ammonia tank, thus achieving a circulation effect. This effectively returns the gas pressure flowing back from the first absorption tower to the interior of return pipe one and the pressure relief cylinder, and finally returns the gas pressure to the interior of the liquid ammonia tank through return pipe two. This achieves the function of depressurizing the interior of the first absorption tower, thereby solving the problem of excessive gas pressure inside the first absorption tower, which causes unstable valve opening and unstable temperature inside the first absorption tower. At the same time, after the pressure is returned and depressurized, the gas pressure return is small, thus solving the problem of ammonia booster pump failure.

[0022] The present invention has the following beneficial effects:

[0023] This invention, by setting up an ammonia storage mechanism 10, firstly inputs liquid ammonia into the ammonia supply pipe 11. When entering the ammonia supply pipe 11, one-way valve 12 is activated first. After the liquid ammonia passes through one-way valve 12, it will be limited by one-way valve 12, allowing the liquid ammonia to flow in but not out. At this point, the liquid ammonia will preferentially flow into the drain pipe 15. Then, one-way valve 3 16 is activated to limit the liquid ammonia flow, preventing it from flowing back. While the liquid ammonia is being transported inside the ammonia supply pipe 11, it will also pass through one-way valve 2 13. One-way valve 2 13 is activated again, preventing the liquid ammonia inside the ammonia supply pipe 11 from flowing back into the drain pipe 15. Finally, the liquid ammonia is transported into the ammonia tank 14. The setting of one-way valve 12, one-way valve 2 13, and one-way valve 3 16 effectively achieves the function of limiting the liquid ammonia flow and preventing backflow.

[0024] This invention, through the setting of a detection mechanism 30, when liquid ammonia enters the liquid ammonia tank 14, activates the ammonia booster pump 31 to extract the liquid ammonia from the one-way valve 12 through the extraction pipe 32. At the same time, the solenoid valves 34 and 35 also start along with the ammonia booster pump 31 and open the valves. The extracted liquid ammonia enters the inlet pipe 33, and at the same time, the liquid ammonia in the outlet pipe 15 enters the inlet pipe 33. Finally, the liquid ammonia is transported to the first-stage absorption tower 4 through the inlet pipe 33. After the liquid ammonia enters the first-stage absorption tower 4, the concentration detector 36 is energized to detect the concentration of liquid ammonia inside the first-stage absorption tower 4. Then, the temperature detector 37 is energized to detect the temperature of liquid ammonia inside the first-stage absorption tower 4. The concentration detector 36 and the temperature detector 37 are used to effectively detect the concentration and temperature of liquid ammonia inside the first-stage absorption tower 4 in real time.

[0025] This invention utilizes a reflux mechanism 50. When the ammonia booster pump 31 continuously supplies liquid ammonia to the first-stage absorption tower 4, a large amount of gas pressure is generated inside the first-stage absorption tower 4. This gas pressure refluxes inside the first-stage absorption tower 4, entering the inlet pipe 33, and then is discharged into the reflux pipe 51 through the inlet pipe 33. When the gas pressure enters the pressure relief cylinder 52, it accumulates inside. When the gas pressure accumulates excessively inside the pressure relief cylinder 52, it generates a large thrust, pushing the sealing disc 56 to slide towards the filter disc 54 on the surface of the support shaft 55. At this time, the outer wall of the sealing disc 56 separates from the inner wall of the sealing ring 53. As the sealing disc 56 slides, it pushes the force-retracting telescopic rod 57 to compress, causing the force-retracting telescopic rod 57 to contract towards the filter disc 54. Due to the separation of the sealing disc 56 and the sealing ring 53... After separation, the gas pressure enters the interior of the second return pipe 58 through the filter plate 54, where it is also filtered. Once inside the second return pipe 58, the gas pressure enters the liquid ammonia tank 14, where it is then drawn by the ammonia booster pump 31, thus achieving a circulation effect. This effectively returns the gas pressure flowing back from the first absorption tower 4 to the first return pipe 51 and the pressure relief cylinder 52, and finally back to the liquid ammonia tank 14 through the second return pipe 58. This achieves the function of depressurizing the interior of the first absorption tower 4, thereby solving the problem of excessive gas pressure inside the first absorption tower 4, which causes unstable valve opening and unstable temperature inside the first absorption tower 4. Furthermore, after pressure is returned and depressurized, the gas pressure return is small, thus solving the problem of ammonia booster pump 31 malfunction.

[0026] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0029] Figure 2 This is a schematic diagram of the overall structure of the ammonia storage mechanism of the present invention;

[0030] Figure 3 This is a schematic diagram of the overall structure of the detection mechanism of the present invention;

[0031] Figure 4 This is a schematic diagram of the overall structure of the reflux mechanism of the present invention;

[0032] Figure 5 This is a schematic diagram of the sealing disc structure of the present invention;

[0033] Figure 6 This is a schematic diagram of the stress-bearing telescopic rod structure of the present invention;

[0034] Figure 7 This is a schematic diagram of the flow structure of a method for controlling the reflux of ammonia in an aqueous urea device according to the present invention.

[0035] The attached diagram lists the components represented by each number as follows:

[0036] In the diagram: 1. Base; 2. Support ring; 3. Support frame; 4. First-stage absorption tower; 5. Gas phase output pipe; 10. Ammonia storage mechanism; 11. Liquid ammonia addition pipe; 12. One-way valve one; 13. One-way valve two; 14. Liquid ammonia tank; 15. Drain pipe; 16. One-way valve three; 30. Detection mechanism; 31. Ammonia booster pump; 32. Liquid extraction pipe; 33. Liquid inlet pipe; 34. Solenoid valve one; 35. Solenoid valve two; 36. Concentration detector; 37. Temperature detector; 50. Reflux mechanism; 51. Reflux pipe one; 52. Pressure relief cylinder; 53. Sealing ring; 54. Filter disc; 55. Support shaft; 56. Sealing disc; 57. Force-bearing telescopic rod; 58. Reflux pipe two. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Please see Figures 1-7 As shown, the present invention is a method and device for controlling the reflux of ammonia in an aqueous urea plant, including a base 1, a support ring 2 and a support frame 3 fixedly connected to the surface of the base 1, an absorption tower 4 fixedly connected to the inner wall of the support frame 3, a gas phase output pipe 5 fixedly connected to the top of the absorption tower 4, and also includes;

[0039] The ammonia storage mechanism 10 includes a drain pipe 15. At this time, liquid ammonia will flow into the interior of the drain pipe 15 first. A one-way valve 16 is provided on the surface of the drain pipe 15. Then, the one-way valve 16 is activated to limit the liquid ammonia and prevent it from flowing back.

[0040] The testing unit 30 includes an inlet pipe 33. The extracted liquid ammonia will enter the interior of the inlet pipe 33, and at the same time, the liquid ammonia inside the drain pipe 15 will enter the interior of the inlet pipe 33. Finally, the liquid ammonia will be transported to the interior of the first-stage absorption tower 4 through the inlet pipe 33. The surface of the inlet pipe 33 is equipped with a second solenoid valve 35. At this time, the first solenoid valve 34 and the second solenoid valve 35 will also be started along with the ammonia booster pump 31 and the valves will be opened.

[0041] The reflux mechanism 50 includes a support shaft 55, which pushes the sealing disc 56 to slide on the surface of the support shaft 55 toward the filter disc 54. The sealing disc 56 is slidably connected to the surface of the support shaft 55, and a force-bearing telescopic rod 57 is fixedly connected to the surface of the sealing disc 56. When the sealing disc 56 slides, it pushes the force-bearing telescopic rod 57 to squeeze.

[0042] Furthermore, the end of the output pipe 5 is connected to the top of the inner wall of a section of the absorption tower 4, and the bottom of the support ring 2 and the support frame 3 are both fixedly connected to the surface of the base 1.

[0043] Furthermore, the ammonia storage mechanism 10 includes an ammonia filling pipe 11. The surface of the ammonia filling pipe 11 is provided with a one-way valve 12 and a one-way valve 2 13. While the liquid ammonia is being transported inside the ammonia filling pipe 11, it will pass through the one-way valve 2 13. First, the liquid ammonia is introduced into the interior of the ammonia filling pipe 11. When it enters the interior of the ammonia filling pipe 11, the one-way valve 12 is activated. After the liquid ammonia passes through the one-way valve 12, the liquid ammonia will pass through the limit of the one-way valve 12. At this time, the liquid ammonia will only enter and not exit. The end of the ammonia filling pipe 11 is fixedly connected to a liquid ammonia tank 14.

[0044] Furthermore, the surface of the liquid ammonia adding pipe 11 is fixedly connected to the inside of the support ring 2, the bottom of the liquid ammonia tank 14 is fixedly connected to the surface of the base 1, the end of the drain pipe 15 is fixedly connected to the surface of the liquid ammonia adding pipe 11, and the end of the liquid ammonia adding pipe 11 is in communication with the inner wall of the liquid ammonia tank 14. At this time, the one-way valve 2 13 is activated to prevent the liquid ammonia inside the liquid ammonia adding pipe 11 from flowing back into the drain pipe 15. Finally, the liquid ammonia is transported to the inside of the liquid ammonia tank 14. The one-way valve 1 12, one-way valve 2 13 and one-way valve 3 16 effectively achieve the function of limiting the flow of liquid ammonia and preventing backflow.

[0045] Furthermore, the detection mechanism 30 includes an ammonia booster pump 31, the output end of which is fixedly connected to a liquid extraction pipe 32. When the ammonia booster pump 31 is started, liquid ammonia is extracted from the one-way valve 12 through the liquid extraction pipe 32. A solenoid valve 34 is installed on the surface of the liquid extraction pipe 32. A concentration detector 36 and a temperature detector 37 are installed on the surface of the gas phase output pipe 5. When liquid ammonia enters the first-stage absorption tower 4, the concentration detector 36 is energized to detect the concentration of liquid ammonia inside the first-stage absorption tower 4. Then, the temperature detector 37 is energized to detect the temperature of liquid ammonia inside the first-stage absorption tower 4. The concentration and temperature of liquid ammonia inside the first-stage absorption tower 4 are effectively detected in real time through the temperature detector 37 and the concentration detector 36.

[0046] Furthermore, the end of the inlet pipe 33 is fixedly connected to the output end of the ammonia booster pump 31, the end of the extraction pipe 32 away from the ammonia booster pump 31 is fixedly connected to the top of the liquid ammonia tank 14, the bottom of the ammonia booster pump 31 is fixedly connected to the surface of the base 1, and the end of the discharge pipe 15 away from the liquid ammonia addition pipe 11 is fixedly connected to the surface of the inlet pipe 33.

[0047] Furthermore, the reflux mechanism 50 includes a reflux pipe 51. When the ammonia booster pump 31 continuously supplies liquid ammonia to the first-stage absorption tower 4, a large amount of gas pressure is generated inside the first-stage absorption tower 4. At this time, the gas pressure will reflux inside the first-stage absorption tower 4, enter the liquid inlet pipe 33, and then be discharged into the reflux pipe 51 through the liquid inlet pipe 33. A pressure relief cylinder 52 is fixedly connected to the end of the reflux pipe 51. When the gas pressure enters the pressure relief cylinder 52, it accumulates inside the pressure relief cylinder 52. When excessive gas pressure accumulates inside the pressure relief cylinder 52, it will generate a large thrust. The inner wall of the pressure relief cylinder 52 is fixedly connected with a sealing ring 53 and a filter disc 54. At this time, the outer wall of the sealing disc 56 will separate from the inner wall of the sealing ring 53. The end of the pressure relief cylinder 52 away from the return pipe 1 51 is fixedly connected to the return pipe 2 58. When the gas pressure enters the interior of the return pipe 2 58, it will enter the interior of the liquid ammonia tank 14. Then, the liquid ammonia tank 14 will be pumped out by the ammonia booster pump 31, thereby achieving the circulation effect.

[0048] Furthermore, the end of the return pipe 51 furthest from the pressure relief cylinder 52 is fixedly connected to the surface of the inlet pipe 33, the surface of the filter disc 54 is fixedly connected to the end of the sealing disc 56, and the end of the force-operated telescopic rod 57 furthest from the sealing disc 56 is fixedly connected to the surface of the filter disc 54, causing the force-operated telescopic rod 57 to retract towards the filter disc 54. Since the sealing disc 56 separates from the sealing ring 53, the air pressure will enter the interior of the return pipe 58 through the filter disc 54, and the air pressure can be filtered by the filter disc 54. The end of the return pipe 58 furthest from the pressure relief cylinder 52 is fixedly connected to the surface of the inlet pipe 33. The surface of the liquid ammonia tank 14 is fixedly connected, which effectively allows the gas pressure returning from the first absorption tower 4 to the inside of the return pipe 51 and the pressure relief cylinder 52, and then the gas pressure to return to the inside of the liquid ammonia tank 14 through the second return pipe 58. This achieves the function of relieving pressure inside the first absorption tower 4, thereby solving the problem of excessive gas pressure inside the first absorption tower 4, which causes unstable valve opening and unstable temperature inside the first absorption tower 4. At the same time, after the pressure is returned and relieved, the gas pressure return is small, thus solving the problem of the ammonia booster pump 31 malfunctioning.

[0049] Furthermore, a method for controlling the reflux of ammonia in an aqueous urea plant includes the following steps:

[0050] S1: While liquid ammonia is being transported inside the liquid ammonia supply pipe 11, it will pass through one-way valve 2 13. At this time, one-way valve 2 13 is activated again to prevent the liquid ammonia inside the liquid ammonia supply pipe 11 from flowing back into the drain pipe 15. Finally, the liquid ammonia is transported into the liquid ammonia tank 14. The one-way valve 1 12, one-way valve 2 13 and one-way valve 3 16 are set to effectively limit the flow of liquid ammonia and prevent it from flowing back.

[0051] S2: When liquid ammonia enters the interior of the first-stage absorption tower 4, the concentration detector 36 is energized and the concentration of liquid ammonia inside the first-stage absorption tower 4 is detected by the concentration detector 36. Then the temperature detector 37 is energized to detect the temperature of liquid ammonia inside the first-stage absorption tower 4. The concentration and temperature of liquid ammonia inside the first-stage absorption tower 4 can be effectively detected in real time by the temperature detector 37 and the concentration detector 36.

[0052] S3: At this time, the outer wall of the sealing disc 56 will separate from the inner wall of the sealing ring 53. When the sealing disc 56 slides, it will push the force-retracting telescopic rod 57 to squeeze, causing the force-retracting telescopic rod 57 to retract towards the filter disc 54. Since the sealing disc 56 and the sealing ring 53 are separated, the air pressure will enter the interior of the return pipe 2 58 through the filter disc 54, and the air pressure can be filtered through the filter disc 54 at the same time.

[0053] S4: When the gas pressure enters the interior of the return pipe 2 58, it enters the interior of the liquid ammonia tank 14. Then, the ammonia booster pump 31 draws the gas pressure from the interior of the liquid ammonia tank 14, thereby achieving a circulation effect. This effectively returns the gas pressure flowing back from the interior of the first-stage absorption tower 4 to the interior of the return pipe 1 51 and the pressure relief cylinder 52, and finally returns the gas pressure to the interior of the liquid ammonia tank 14 through the return pipe 2 58. This achieves the function of depressurizing the interior of the first-stage absorption tower 4, thereby solving the problem of excessive gas pressure inside the first-stage absorption tower 4, which causes unstable valve opening and unstable temperature inside the first-stage absorption tower 4. At the same time, after the pressure is returned and depressurized, the gas pressure return is small, thus solving the problem of the ammonia booster pump 31 malfunctioning.

[0054] In use, liquid ammonia is first introduced into the liquid ammonia filling pipe 11. Upon entering the pipe, one-way valve 12 is activated. After passing through check valve 12, the liquid ammonia will be limited by its flow limit, allowing only inflow and no outflow. The liquid ammonia will then preferentially flow into the drain pipe 15. Next, check valve 3 16 is activated to limit the backflow of liquid ammonia. While being transported within the filling pipe 11, the liquid ammonia also passes through check valve 2 13. Activating check valve 2 13 again prevents the liquid ammonia in the filling pipe 11 from flowing back into the drain pipe 15. Finally, the liquid ammonia is delivered to the liquid ammonia tank 1. Inside the liquid ammonia tank 14, when liquid ammonia enters, the ammonia booster pump 31 is activated to extract liquid ammonia from the one-way valve 12 through the extraction pipe 32. At the same time, solenoid valves 34 and 35 are also activated along with the ammonia booster pump 31 and open. The extracted liquid ammonia enters the inlet pipe 33, and simultaneously, the liquid ammonia in the outlet pipe 15 enters the inlet pipe 33. Finally, the liquid ammonia is transported to the first-stage absorption tower 4 through the inlet pipe 33. After the liquid ammonia enters the first-stage absorption tower 4, the concentration detector 36 is energized and used to detect the contents of the first-stage absorption tower 4. The concentration of liquid ammonia is measured, and then the temperature detector 37 is energized to detect the temperature of the liquid ammonia inside the first-stage absorption tower 4. As the ammonia booster pump 31 continuously supplies liquid ammonia into the first-stage absorption tower 4, a large amount of gas pressure is generated inside the first-stage absorption tower 4. At this time, the gas pressure will flow back inside the first-stage absorption tower 4 and enter the interior of the liquid inlet pipe 33. Then, the gas pressure is discharged into the interior of the return pipe 51 through the liquid inlet pipe 33. When the gas pressure enters the interior of the pressure relief cylinder 52 and accumulates inside the pressure relief cylinder 52, when too much gas pressure accumulates inside the pressure relief cylinder 52, it will generate a large thrust and push the sealing disc 56 against the support shaft 55. The surface slides towards the filter disc 54. At this time, the outer wall of the sealing disc 56 will separate from the inner wall of the sealing ring 53. When the sealing disc 56 slides, it will push the force-retracting telescopic rod 57 to squeeze, causing the force-retracting telescopic rod 57 to contract towards the filter disc 54. Since the sealing disc 56 separates from the sealing ring 53, the air pressure will enter the interior of the return pipe 2 58 through the filter disc 54. At the same time, the air pressure can be filtered by the filter disc 54. When the air pressure enters the interior of the return pipe 2 58, it will enter the interior of the liquid ammonia tank 14. Then, the liquid ammonia tank 14 will be drawn by the ammonia booster pump 31, thereby achieving the circulation effect.

[0055] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. An aqueous urea device, comprising a base (1), wherein a support ring (2) and a support frame (3) are fixedly connected to the surface of the base (1), a section of absorption tower (4) is fixedly connected to the inner wall of the support frame (3), and a gas phase output pipe (5) is fixedly connected to the top of the section of absorption tower (4), characterized in that, Also includes; The ammonia storage mechanism (10) includes a drain pipe (15) and an ammonia addition pipe (11), and a one-way valve (16) is provided on the surface of the drain pipe (15). The surface of the liquid ammonia adding pipe (11) is provided with one-way valve one (12) and one-way valve two (13), and the end of the liquid ammonia adding pipe (11) is fixedly connected to a liquid ammonia tank (14). The end of the drain pipe (15) is fixedly connected to the surface of the liquid ammonia pipe (11); The detection mechanism (30) includes an inlet pipe (33) and an ammonia booster pump (31), and a solenoid valve (35) is provided on the surface of the inlet pipe (33). The output end of the ammonia booster pump (31) is fixedly connected to a liquid extraction pipe (32), and a solenoid valve (34) is provided on the surface of the liquid extraction pipe (32). A concentration detector (36) and a temperature detector (37) are provided on the surface of the gas phase output pipe (5). The end of the inlet pipe (33) is fixedly connected to the output end of the ammonia booster pump (31), and the end of the outlet pipe (15) away from the liquid ammonia pipe (11) is fixedly connected to the surface of the inlet pipe (33). The reflux mechanism (50) includes a support shaft (55) and a reflux pipe (51). A sealing disc (56) is slidably connected to the surface of the support shaft (55), and a force-bearing telescopic rod (57) is fixedly connected to the surface of the sealing disc (56). The end of the first return pipe (51) is fixedly connected to a pressure relief cylinder (52), and the inner wall of the pressure relief cylinder (52) is fixedly connected to a sealing ring (53) and a filter disc (54). The end of the pressure relief cylinder (52) away from the first return pipe (51) is fixedly connected to a second return pipe (58). The end of the first return pipe (51) away from the pressure relief cylinder (52) is fixedly connected to the surface of the liquid inlet pipe (33), and the end of the second return pipe (58) away from the pressure relief cylinder (52) is fixedly connected to the surface of the liquid ammonia tank (14).

2. The aqueous urea apparatus according to claim 1, characterized in that: The end of the gas phase output pipe (5) is connected to the top of the inner wall of a section of the absorption tower (4), and the bottom of the support ring (2) and the support frame (3) are fixedly connected to the surface of the base (1).

3. The aqueous urea apparatus according to claim 2, characterized in that: The surface of the liquid ammonia adding pipe (11) is fixedly connected to the inside of the support ring (2), the bottom of the liquid ammonia tank (14) is fixedly connected to the surface of the base (1), and the end of the liquid ammonia adding pipe (11) is in communication with the inner wall of the liquid ammonia tank (14).

4. The aqueous urea apparatus according to claim 3, characterized in that: The end of the pumping pipe (32) away from the ammonia booster pump (31) is fixedly connected to the top of the liquid ammonia tank (14), and the bottom of the ammonia booster pump (31) is fixedly connected to the surface of the base (1).

5. The aqueous urea apparatus according to claim 4, characterized in that: The surface of the filter disc (54) is fixedly connected to the end of the sealing disc (56), and the end of the force-bearing telescopic rod (57) away from the sealing disc (56) is fixedly connected to the surface of the filter disc (54).

6. The method for controlling the reflux of ammonia in an aqueous urea plant according to claim 5, characterized in that, Includes the following steps: S1: While liquid ammonia is being transported inside the liquid ammonia supply pipe (11), it will pass through one-way valve two (13). At this time, one-way valve two (13) is activated again to prevent the liquid ammonia inside the liquid ammonia supply pipe (11) from flowing back into the drain pipe (15). Finally, the liquid ammonia is transported to the liquid ammonia tank (14). By effectively setting one-way valve one (12), one-way valve two (13) and one-way valve three (16), the function of limiting the flow of liquid ammonia and preventing it from flowing back is achieved. S2: When liquid ammonia enters the interior of the first-stage absorption tower (4), the concentration detector (36) is energized and the concentration of liquid ammonia inside the first-stage absorption tower (4) is detected by the concentration detector (36). Then the temperature detector (37) is energized to detect the temperature of liquid ammonia inside the first-stage absorption tower (4). The concentration and temperature of liquid ammonia inside the first-stage absorption tower (4) are effectively detected in real time by the temperature detector (37) and the concentration detector (36). S3: At this time, the outer wall of the sealing disc (56) will separate from the inner wall of the sealing ring (53). When the sealing disc (56) slides, it will push the force-retracting telescopic rod (57) to squeeze, causing the force-retracting telescopic rod (57) to contract in the direction of the filter disc (54). Since the sealing disc (56) and the sealing ring (53) are separated, the air pressure will enter the interior of the return pipe two (58) through the filter disc (54), and the air pressure can be filtered through the filter disc (54). S4: When the gas pressure enters the interior of the return pipe 2 (58), it will enter the interior of the liquid ammonia tank (14). Then, the liquid ammonia tank (14) will be drawn by the ammonia booster pump (31) to achieve the circulation effect. This effectively returns the gas pressure inside the first absorption tower (4) to the interior of the return pipe 1 (51) and the pressure relief cylinder (52). Finally, the gas pressure is returned to the interior of the liquid ammonia tank (14) through the return pipe 2 (58), which achieves the function of depressurizing the interior of the first absorption tower (4). This solves the problem of excessive gas pressure inside the first absorption tower (4), which causes unstable valve opening and unstable temperature inside the first absorption tower (4). At the same time, after the pressure is returned and depressurized, the gas pressure return is small, thus solving the problem of the ammonia booster pump (31) malfunctioning.

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