Device for reducing ammonia discharge of ammonia water tank and urine tank in urea process

Abstract

The utility model discloses a device for reducing the ammonia discharge amount of an ammonia water tank and a urine tank in a urea process in the technical field of urea production. The device comprises an emptying cylinder, a process condensate spraying structure, a two-section pipe joint device, a urine tank, a urine buffer tank, an ammonia water tank, a flow adjusting device, a low-pressure absorption tower ammonia water heat exchanger, a condensate pump and the like. The sprayers are respectively arranged in the pipe joints and are connected with corresponding storage tank gas phase pipes, and the flow adjusting device can accurately control the flow of spraying liquid; gas inlets at the bottoms of the two pipe sections are additionally provided with special structures, so that gas is uniformly distributed, the nozzle type selection is scientific and reasonable, and ammonia gas can be efficiently absorbed; the device uses a low-pressure absorption tower ammonia water heat exchanger to provide dilute ammonia water at a proper temperature as a spraying liquid, and a condensate pump drives a process condensate to circulate. The device effectively solves the problems of large ammonia content fluctuation, difficult process operation and high energy consumption of the emptying cylinder in the existing urea process, reduces the ammonia content of the ammonia water tank, the gas phase pipe of the urine tank and the emptying cylinder, and reduces the ammonia loss.

Description

Technical Field

[0001] This utility model relates to the field of urea production technology, specifically a device for reducing ammonia emissions from ammonia tanks and urea tanks in the urea process. Background Technology

[0002] Currently, both the ammonia tank and urine tank in the urea plant are atmospheric pressure storage tanks. After passing through the flash evaporator, the liquid phase enters the urine buffer tank at a temperature of approximately 98°C, and the main urine tank at approximately 84°C. At this high temperature, free ammonia evaporates into the gas phase space, with a content of approximately 5.12%, and enters the venting cylinder directly through a DN100 gas phase pipeline. The free ammonia content in the gas phase of the ammonia tank is approximately 11.3%, mainly originating from the evaporation of free ammonia from the high-concentration ammonia solution in the flash condenser liquid phase and the liquid ammonia pump replacement fluid, and also entering the venting cylinder directly through the gas phase pipeline.

[0003] When gaseous substances containing high concentrations of free ammonia from the ammonia tank and urine tank enter the venting cylinder, although they undergo condensate washing at two points within the venting cylinder, the ammonia content fluctuates between 0.01% and 3%, making process operation difficult and affecting the venting cylinder's emission standards. As the unit's operating cycle increases, the condensate heat exchange efficiency decreases, the condensate temperature rises, and the condensate washing effect in the venting cylinder diminishes. Increasing the condensate washing volume to control the absorption effect leads to higher ammonia levels in the unit, resulting in increased unit consumption and energy consumption.

[0004] To address the aforementioned issues, this application provides a device for reducing ammonia emissions from ammonia tanks and urea tanks during the urea process. Summary of the Invention

[0005] The purpose of this utility model is to solve the problems mentioned in the background art above, and to provide a device for reducing the ammonia discharge from the ammonia tank and urine tank in the urea process.

[0006] To achieve the above objectives, this utility model specifically adopts the following technical solution:

[0007] A device for reducing ammonia emissions from ammonia tanks and urea tanks in a urea process, comprising:

[0008] Vent tube;

[0009] The process condensate spray structure includes nozzle A and nozzle B;

[0010] The two-section pipe section device includes pipe section A and pipe section B, which are connected in sequence by a pipe, and the top of pipe section B is connected to the vent cylinder by a pipe.

[0011] A urine tank and a urine buffer tank, wherein the gas phase pipes of the urine tank and the urine buffer tank are connected to the pipe section A via pipes;

[0012] Ammonia tank, wherein the gas phase pipe of the ammonia tank is connected to the pipe section B via a pipeline;

[0013] The nozzle A is installed inside the pipe section A and is connected to the gas phase pipe of the urine tank through a pipe; the nozzle B is installed inside the pipe section B and is connected to the gas phase pipe of the ammonia tank through a pipe.

[0014] A flow regulating device, comprising a shut-off valve A and a shut-off valve B, respectively installed on the pipes of nozzle A and nozzle B, for controlling the flow rate of the spray liquid;

[0015] The bottom of pipe section B is connected to the ammonia tank via a discharge pipe;

[0016] Ammonia heat exchanger for low-pressure absorption tower.

[0017] Furthermore, the flow regulating device includes:

[0018] Flow transmitter A and flow transmitter B are respectively installed at the rear ends of shut-off valve A and shut-off valve B;

[0019] Pipeline filter, installed upstream of the flow control valve;

[0020] A spare condensate valve is provided, with one end connected to the main spray dilute ammonia water pipe and the other end left unconnected for later use.

[0021] The controller is connected to the flow transmitter and the control shielded cable, respectively, and is used to adjust the flow rate of the spray liquid.

[0022] Furthermore, the bottom air inlet ports of pipe section A and pipe section B are respectively equipped with ring plate A and ring plate B to ensure uniform gas distribution and improve washing efficiency.

[0023] Furthermore, the selection requirements for nozzle A and nozzle B are as follows:

[0024] The washing liquid temperature is 50℃;

[0025] The working pressure is 1.0–1.2 MPa;

[0026] The flow rate of a single nozzle is 0.1–0.2 m³ / h;

[0027] A circular area with a coverage area of ​​500-600 mm;

[0028] The spray pattern is a wide-angle 120° solid cone.

[0029] Furthermore, the bottom of pipe section B is connected to the ammonia tank via a discharge pipe and an overflow pipe at the bottom of the venting cylinder for ammonia recovery.

[0030] Furthermore, nozzle A and nozzle B are respectively connected to the ammonia water heat exchanger of the low-pressure absorption tower via pipelines. The ammonia water heat exchanger of the low-pressure absorption tower is used to provide dilute ammonia water at a suitable temperature as the spray liquid.

[0031] Furthermore, the device also includes a condensate pump for driving the process condensate to circulate in the system, and a shut-off valve C is provided on the pipe connecting the condensate pump and the pipe filter.

[0032] Furthermore, the device calculates that the pressure of the liquid seal cap is approximately 3-3.47 MPa, and under actual production conditions, the gas phase pressure of the urine tank and the ammonia tank is insufficient to break the liquid seal, thus ensuring that the addition of spraying does not affect the liquid seal protection of the two storage tanks.

[0033] Compared with the prior art, the beneficial effects of this utility model are:

[0034] 1. This solution uses specialized nozzles to spray and wash the gas phase of the ammonia tank and urine tank, which can efficiently absorb the free ammonia, greatly reduce the amount of ammonia entering the venting cylinder, stabilize the ammonia content in the venting cylinder, reduce fluctuations in ammonia emission indicators, make it easier to meet emission standards, and effectively reduce ammonia loss.

[0035] 2. This solution is equipped with a precise flow regulation device, which can flexibly and accurately adjust the spray liquid flow rate according to the actual ammonia emission status and process requirements, making the process operation more controllable, reducing the difficulty of operation, and reducing the reliance on the operator's experience.

[0036] 3. The carefully selected nozzles in this solution are scientifically designed in terms of temperature, pressure, flow rate, coverage area, and spray shape to ensure that the washing liquid is in full contact with the gaseous ammonia. At the same time, the special structure installed at the bottom of the pipe section ensures uniform gas distribution, further increasing the gas-liquid contact area and time. Even if the operation cycle of the device is extended, good washing effect can still be guaranteed.

[0037] 4. With its precise flow control and efficient spray system, this device ensures that ammonia emissions meet standards while avoiding excessive use of condensate, thus reducing operating costs.

[0038] 5. This device recovers the ammonia-containing liquid after washing to an ammonia tank, realizing the recycling of ammonia resources. Furthermore, the condensate is recycled, reducing the consumption of fresh condensate, improving resource utilization, and meeting the requirements of green production. Attached Figure Description

[0039] Figure 1 This is a flowchart illustrating the present invention.

[0040] In the diagram: 1. Vent cylinder; 2. Condensate pump; 3. Shut-off valve C; 4. Shut-off valve A; 5. Ammonia heat exchanger in low-pressure absorption tower; 6. Pipeline filter; 7. Shut-off valve B; 8. Flow transmitter B; 9. Flow transmitter A; 10. Nozzle B; 11. Nozzle A; 12. Pipe section B; 13. Pipe section A; 14. Ring plate B; 15. Ring plate A; 16. Ammonia tank; 17. Urine tank; 18. Urine buffer tank. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings.

[0042] This application provides a device for reducing ammonia emissions from the ammonia tank and urea tank in a urea process. It primarily addresses the issue that after the gaseous phase containing high concentrations of free ammonia from the ammonia tank and urea tank enters the venting cylinder, although it undergoes washing with condensate at two points within the venting cylinder, the ammonia content fluctuates between 0.01% and 3%, making process operation difficult and affecting the emission standards of the venting cylinder. As the operating cycle of the device increases, the condensate heat exchange efficiency decreases, the condensate temperature rises, and the condensate washing effect in the venting cylinder decreases. Increasing the condensate washing volume to control the absorption effect leads to increased ammonia levels, resulting in increased device consumption and energy consumption. The following technical solution is provided, which will be discussed in conjunction with… Figure 1 Please provide a detailed explanation:

[0043] A device for reducing ammonia emissions from ammonia tanks and urea tanks in a urea process mainly includes:

[0044] Vent tube 1;

[0045] The process condensate spray structure includes nozzle A11 and nozzle B10;

[0046] The two-section pipe section device includes pipe section A13 and pipe section B12. Pipe section A13 and pipe section B12 are connected in sequence by pipes, and the top of pipe section B12 is connected to the vent cylinder 1 by pipes.

[0047] The urine tank 17 and the urine buffer tank 18 are connected to the gas phase pipes of the urine tank 17 and the urine buffer tank 18 via pipes to pipe section A13.

[0048] Ammonia tank 16, the gas phase pipe of ammonia tank 16 is connected to pipe section B12 through a pipe;

[0049] Nozzle A11 is installed inside pipe section A13 and connected to the gas phase pipe of urine tank 17 via a pipe; Nozzle B10 is installed inside pipe section B12 and connected to the gas phase pipe of ammonia tank 16 via a pipe.

[0050] A flow regulating device, comprising shut-off valve A4 and shut-off valve B7, which are respectively installed on the pipes of nozzle A11 and nozzle B10, for controlling the flow rate of the spray liquid;

[0051] The bottom of pipe section B12 is connected to ammonia tank 16 via a discharge pipe;

[0052] Low-pressure absorption tower ammonia water heat exchanger 5.

[0053] The operation is as follows: After the device is turned on, the ammonia water heat exchanger 5 in the low-pressure absorption tower exchanges heat with the process condensate, providing dilute ammonia water at a suitable temperature as the spray liquid. The dilute ammonia water flows through the pipeline to the nozzles A11 and B10. During this process, the operator can control the flow rate of the spray liquid by controlling the opening of the shut-off valves A4 and B7 according to the actual working conditions and using the flow regulating device. The ammonia-containing gas phase volatilized from the urine tank 17 and urine buffer tank 18, as well as the ammonia-containing gas phase volatilized from the ammonia water tank 16, enter the pipe section A13 and pipe section B12 through their respective gas phase pipes. The nozzles A11 and B10 spray out the dilute ammonia water, which comes into full contact with the ammonia-containing gas phase and absorbs the ammonia gas. After washing, the liquid flows into the ammonia water tank 16 for recycling through the discharge pipe at the bottom of the pipe section B12.

[0054] This device has significant beneficial effects: it uses nozzles A11 and B10 to perform targeted spraying and washing of the ammonia-containing gas phase, and combines the flow regulating device to precisely control the flow rate of the spray liquid, effectively reducing the ammonia content in the gas phase of the urine tank 17, urine buffer tank 18, and ammonia water tank 16, thereby reducing the ammonia content in the venting cylinder 1, reducing ammonia loss, and making it easier for the emissions from the venting cylinder 1 to meet standards. The low-pressure absorption tower ammonia water heat exchanger 5 provides dilute ammonia water at a suitable temperature, ensuring the effectiveness of the spraying and washing. At the same time, the bottom discharge pipe of pipe section B12 recovers the washing liquid to the ammonia water tank 16, realizing the recycling of ammonia resources, reducing the overall consumption of the device, and improving both production efficiency and economic and environmental benefits.

[0055] Specifically, the flow regulating device includes:

[0056] Flow transmitters A9 and B8 are installed at the rear ends of shut-off valves A4 and B7, respectively. Flow transmitter A9 is precisely installed at the rear end of shut-off valve A4, and flow transmitter B8 is also precisely installed at the rear end of shut-off valve B7, to ensure that the flow rate data of the spray liquid passing through the corresponding nozzle pipe can be monitored in real time and accurately.

[0057] Pipeline filter 6 is installed upstream of the flow control valve;

[0058] A backup condensate valve is provided, with one end connected to the main spray dilute ammonia water pipe and the other end temporarily unconnected. This is to provide the possibility of backup spray liquid delivery in case of emergencies or special operating conditions.

[0059] The controller is connected to flow transmitters A9 and B8 via shielded control cables to regulate the flow rate of the spray liquid.

[0060] The operation is as follows: During device operation, flow transmitters A9 and B8 continuously monitor the real-time flow rate of the spray liquid in the pipelines of nozzles A11 and B10, and transmit the flow data to the controller. After receiving this data, the controller analyzes and processes it according to preset flow parameters or actual production needs. When the actual flow rate deviates from the set value, the controller sends control signals to shut-off valves A4 and B7 via the shielded control cable to adjust the valve opening, thereby precisely controlling the spray liquid flow rate. If the system detects abnormal fluctuations in the spray liquid flow rate, nozzle blockage, or other conditions affecting the spraying effect, the backup condensate valve can be opened to introduce backup spray liquid to maintain stable operation of the device. Simultaneously, when impurities accumulate in the pipeline filter 6, causing a decrease in filtration efficiency, it can be cleaned or replaced to ensure the normal operation of the flow regulation device.

[0061] The coordinated operation of flow transmitters A9 and B8 with the controller enables precise regulation of the spray liquid flow rate. It can adjust the spray liquid dosage in real time based on changes in the gaseous ammonia content in the ammonia tank 16 and urine tank 17, ensuring effective ammonia absorption while avoiding waste of spray liquid and reducing operating costs. The pipeline filter 6 effectively filters impurities in the spray liquid, preventing nozzle clogging, ensuring stable and efficient nozzle operation, extending nozzle lifespan, and thus guaranteeing stable operation of the entire unit. The backup condensate valve provides an emergency backup solution, enhancing the reliability and stability of the unit. In case of emergencies, it can quickly switch to the backup spray liquid, avoiding problems such as excessive ammonia emissions due to spray interruption, and improving the unit's ability to cope with risks.

[0062] Furthermore, ring plates A15 and B14 are respectively installed at the bottom air inlets of pipe sections A13 and B12 to ensure uniform gas distribution and improve washing efficiency. Uniform gas distribution allows the spray liquid to come into more comprehensive contact with ammonia-containing gas, avoiding situations where the gas concentration in some areas is too high and washing is insufficient. This greatly improves the absorption effect of ammonia, further reducing the ammonia content in the gas phase of urine tank 17, ammonia water tank 16, and venting cylinder 1, thus reducing ammonia emissions and environmental pollution. On the other hand, improved washing efficiency means that under the same production conditions, the amount of spray liquid used can be reduced, lowering the operating cost of the device. At the same time, the installation of ring plates A15 and B14 helps optimize the overall operating performance of the device, enhances the stability of device operation, reduces problems such as localized corrosion or damage to equipment that may be caused by uneven gas distribution, extends the service life of the equipment, and improves the safety and reliability of production.

[0063] In this embodiment, the selection requirements for nozzles A11 and B10 are as follows: washing liquid temperature is 50℃; working pressure is 1.0~1.2MPa; single nozzle flow rate is 0.1~0.2m³ / h; coverage area is a circular area of ​​500~600mm; spray shape is a wide-angle 120° solid cone.

[0064] The washing liquid temperature of 50℃ and the working pressure of 1.0-1.2MPa ensure that the nozzles operate under optimal conditions, which is beneficial to improving the absorption efficiency of ammonia by the spray liquid. The single nozzle flow rate of 0.1-0.2m³ / h ensures sufficient washing of the ammonia-containing gas phase while avoiding waste of the spray liquid and reducing the operating cost of the equipment. The coverage area of ​​the 500-600mm circular area and the wide-angle 120° solid cone spray shape allow the spray liquid to be distributed more widely and evenly within the pipe section, greatly increasing the contact area and contact time between the spray liquid and the ammonia-containing gas phase, thereby more effectively absorbing ammonia, reducing the ammonia content in the ammonia tank 16, the urine tank 17 gas phase pipe and the venting cylinder 1, reducing ammonia loss, and improving the environmental performance and economic benefits of the urea production process.

[0065] Furthermore, the bottom of pipe section B12 is connected to the ammonia tank 16 via a discharge pipe and an overflow pipe at the bottom of the venting cylinder 1. This enables the effective recovery of ammonia from the washing liquid, avoids ammonia waste, improves ammonia utilization, and reduces production costs. Ammonia that would otherwise be emitted with the exhaust gas can now be collected and reused, increasing economic benefits. On the other hand, it reduces ammonia emissions, lowers environmental pollution, and meets environmental protection requirements. By recovering ammonia, the ammonia content in the venting cylinder 1 is reduced, making it easier for the emissions from the venting cylinder 1 to meet environmental standards. This reduces the environmental pressure of the urea production process and improves the green and environmentally friendly performance of the entire urea production process.

[0066] Spray nozzles A11 and B10 are connected to the ammonia water heat exchanger 5 of the low-pressure absorption tower via pipelines. The ammonia water heat exchanger 5 provides dilute ammonia water at a suitable temperature as the spray liquid, creating favorable conditions for efficient spraying by the nozzles. The spray liquid at a suitable temperature can enhance the absorption effect of ammonia gas, improve the washing efficiency, and thus more effectively reduce the ammonia content in the ammonia water tank 16, the urea tank 17, the gas phase pipe, and the venting cylinder 1, thereby reducing ammonia emissions and improving environmental performance. Secondly, this design makes the supply of spray liquid more stable and reliable, ensuring that the device can operate continuously and stably, avoiding problems such as poor washing effect and fluctuations in device operation caused by unsuitable spray liquid temperature or unstable supply, improving the stability and reliability of the entire urea production process, thereby increasing production efficiency and reducing production costs.

[0067] The device also includes a condensate pump 2, which drives the process condensate to circulate in the system. A shut-off valve C3 is installed on the pipeline connecting the condensate pump 2 and the pipeline filter 6. The condensate pump 2 drives the process condensate to circulate, ensuring a continuous supply of spray liquid. This allows the device to continuously wash the ammonia gas volatilized from the ammonia tank 16 and the urine tank 17, maintaining a stable ammonia absorption efficiency, thereby stabilizing the ammonia emission index of the venting cylinder 1 and reducing ammonia loss. The shut-off valve C3 installed before the pipeline filter 6 allows operators to flexibly control the flow of process condensate according to actual conditions. When maintenance, cleaning, or replacement of the pipeline filter 6 is required, the shut-off valve C3 can be closed to stop the flow of process condensate, preventing liquid leakage in the system and ensuring the smooth progress of maintenance work. At the same time, it can also prevent impurities from entering the system during maintenance, affecting the normal operation of the device, and improving the reliability and maintainability of the device.

[0068] It should be noted that the device calculates and determines that the pressure of the liquid seal cap is approximately 3-3.47 MPa. Under actual production conditions, the gas phase pressure of urine tank 17 and ammonia tank 16 is insufficient to break the liquid seal, ensuring that the addition of spraying does not affect the liquid seal protection of the two tanks. Even after the spraying system is turned on, the pressure changes and fluid disturbances caused by the spraying operation will not cause the gas phase pressure of urine tank 17 and ammonia tank 16 to exceed the pressure threshold of the liquid seal cap, thus ensuring that the liquid seal protection of the two tanks is not affected. This precise calculation and strict control of the liquid seal cap pressure, as well as the design that ensures that the gas phase pressure of urine tank 17 and ammonia tank 16 cannot break the liquid seal under actual production conditions, are crucial.

[0069] The specific operating procedure for this device is as follows:

[0070] First, the condensate pump 2 is turned on, and the process condensate begins to circulate in the system under its drive. The process condensate first passes through the pipeline filter 6 to remove any possible impurities, and then enters the ammonia heat exchanger 5 of the low-pressure absorption tower. The ammonia heat exchanger 5 of the low-pressure absorption tower heats the process condensate into dilute ammonia water at a suitable temperature (50°C). This dilute ammonia water is used as a spray liquid and is transported to nozzles A11 and B10 through pipelines.

[0071] Next, during the spraying process, flow transmitters A9 and B8 continuously monitor the flow rate of the spray liquid in the nozzle pipes and transmit the real-time data to the controller. The controller analyzes and processes the received data based on preset flow parameters and actual production needs. If a deviation is detected between the actual flow rate and the set value, a control signal is sent to shut-off valves A4 and B7 via the shielded control cable to precisely adjust the valve opening, thereby accurately controlling the spray liquid flow rate. At this time, the ammonia-containing gas phase volatilized from the urine tank 17 and urine buffer tank 18, as well as the ammonia water tank... 16. The volatile ammonia-containing gas phase enters pipe section A13 and pipe section B12 through their respective gas phase pipes. The ring plates A15 and B14 at the bottom air inlets of pipe section A13 and pipe section B12 play a role in ensuring uniform distribution of the incoming gas. Spray nozzles A11 and B10 spray dilute ammonia water at a flow rate of 0.1-0.2 m³ / h under a washing liquid temperature of 50°C and a working pressure of 1.0-1.2 MPa, forming a wide-angle 120° solid cone spray. It fully contacts the ammonia-containing gas phase within a circular area of ​​500-600 mm, efficiently absorbing the ammonia gas.

[0072] Finally, the liquid that has completed the washing task flows through the discharge pipe at the bottom of pipe section B12 and then through the overflow pipe at the bottom of venting cylinder 1 into ammonia tank 16, realizing the recycling of ammonia resources.

[0073] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A device for reducing ammonia emissions from an ammonia water tank and a urea tank in a urea process, characterized by The device comprises: a venting cylinder (1); a process condensate spraying structure, comprising a spraying head A (11) and a spraying head B (10); a two-section pipe joint device, comprising a pipe joint A (13) and a pipe joint B (12), which are connected in sequence by pipes, and the top of the pipe joint B (12) is connected to the venting cylinder (1) by a pipe; a urine tank (17) and a urine buffer tank (18), the gas phase pipes of which are connected to the pipe joint A (13) by pipes; an ammonia water tank (16), the gas phase pipe of which is connected to the pipe joint B (12) by a pipe; the spraying head A (11) is arranged in the pipe joint A (13) and is connected to the gas phase pipe of the urine tank (17) by a pipe; the spraying head B (10) is arranged in the pipe joint B (12) and is connected to the gas phase pipe of the ammonia water tank (16) by a pipe; a flow regulating device, comprising a stop valve A (4) and a stop valve B (7), which are respectively installed on the pipes of the spraying head A (11) and the spraying head B (10) to control the flow of the spraying liquid; the bottom of the pipe joint B (12) is connected to the ammonia water tank (16) by a discharge pipe; a low-pressure absorption tower ammonia water heat exchanger (5).

2. The device for reducing ammonia emission of ammonia tank and urea tank in urea process according to claim 1, characterized in that: The flow regulating device comprises: a flow transmitter A (9) and a flow transmitter B (8), which are respectively installed at the rear ends of the stop valve A (4) and the stop valve B (7); a pipe filter (6) installed at the front end of the flow control valve; a standby condensate valve, one end of which is connected to the spraying dilute ammonia water main pipe and the other end is not connected for standby; a controller connected to the flow transmitters and control shielding cables to adjust the flow of the spraying liquid.

3. The device for reducing ammonia emission of ammonia tank and urea tank in a urea process according to claim 1, characterized in that: The bottom gas inlet pipes of the pipe joint A (13) and the pipe joint B (12) are respectively provided with a ring plate A (15) and a ring plate B (14) to uniformly distribute the gas and improve the washing efficiency.

4. The device for reducing ammonia emission of ammonia tank and urea tank in a urea process according to claim 1, characterized in that: The selection requirements of the spraying head A (11) and the spraying head B (10) are: the temperature of the washing liquid is 50℃; the working pressure is 1.0-1.2 MPa; the flow of a single spraying head is 0.1-0.2 m³ / h; the coverage area is a circular area of 500-600 mm; the spray shape is a wide-angle 120° solid cone.

5. The device for reducing ammonia emission of ammonia tank and urea tank in a urea process according to claim 1, characterized in that: The bottom of the pipe joint B (12) is connected to the ammonia water tank (16) by a discharge pipe and an overflow pipe at the bottom of the venting cylinder (1) to recover ammonia.

6. The device for reducing ammonia emission of ammonia tank and urea tank in a urea process according to claim 1, characterized in that: The spraying head A (11) and the spraying head B (10) are respectively connected to the low-pressure absorption tower ammonia water heat exchanger (5) by pipes, which is used to provide dilute ammonia water with a suitable temperature as the spraying liquid.

7. The device for reducing ammonia emission of ammonia tank and urea tank in a urea process according to claim 2, characterized in that: The device further comprises a condensate pump (2) for driving the circulation of the process condensate in the system, and a stop valve C (3) is arranged on the pipe connected to the pipe filter (6).

8. The device for reducing ammonia emission of ammonia tank and urea tank in a urea process according to claim 1, characterized in that: The device determines that the pressure of the liquid seal cover is about 3-3.47 MPa through calculation, and in actual production conditions, the gas phase pressure of the urine tank (17) and the ammonia tank (16) is not enough to break the liquid seal, so as to ensure that the liquid seal protection of the two storage tanks is not affected after spraying.

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