Dust recovery system of urea prilling tower

Abstract

The utility model belongs to the technical field of dust recovery, and particularly relates to a dust recovery system of a urea prilling tower. Comprising a liquid absorption device arranged at an air outlet in the top of a urea prilling tower, a collecting tank is arranged below the liquid absorption device, a circulating tank is arranged below the collecting tank, the collecting tank is communicated with the circulating tank through a circulating downcomer, and the circulating tank is communicated with the liquid absorption device through a circulating pump. The liquid absorbing device comprises a first atomizing nozzle layer, a second atomizing nozzle layer and a flushing nozzle layer which are sequentially arranged from bottom to top; a first-stage separator is arranged between the first atomizing nozzle layer and the second atomizing nozzle layer, a second-stage separator is arranged between the second atomizing nozzle layer and the flushing nozzle layer, a third-stage separator is arranged above the flushing nozzle layer, and the third-stage separator comprises a plurality of air coolers. According to the utility model, the content of urea dust discharged into the atmosphere is reduced, and the environment-friendly requirement is met.

Description

Technical Field

[0001] The utility model belongs to the technical field of dust recovery, and in particular relates to a dust recovery system of a urea granulation tower. Background Art

[0002] In the urea industry, the natural ventilation granulation tower is a key device for forming urea melt. The urea melt is sprayed at a high point of the tower and freely falls to the material trough for collection. Cold air exchanges heat with the raw materials from the bottom of the tower to cool the raw materials. In this process, exhaust gas with a certain amount of urea dust will be formed. How to recover the urea dust in the exhaust gas and reduce the urea dust content discharged into the atmosphere is a problem that needs to be solved at present.

[0003] To this end, this design transforms the dust recovery system of the granulation tower. Utility Model Content

[0004] The technical problem to be solved by the utility model is: how to reduce the content of urea dust discharged into the atmosphere.

[0005] In order to solve the above technical problems, the utility model provides the following technical solutions:

[0006] A dust recovery system for a urea granulation tower comprises a liquid absorption device arranged at an air outlet at the top of the urea granulation tower, a collecting tank is arranged below the liquid absorption device, a circulating tank is arranged below the collecting tank, the collecting tank is connected with the circulating tank through a circulating downcomer, the circulating tank is connected with the liquid absorption device through a circulating pump, the liquid absorption device comprises a first atomizing nozzle layer, a second atomizing nozzle layer and a flushing nozzle layer arranged in sequence from bottom to top; a primary separator is arranged between the first atomizing nozzle layer and the second atomizing nozzle layer, a secondary separator is arranged between the second atomizing nozzle layer and the flushing nozzle layer, a tertiary separator is arranged above the flushing nozzle layer, and the tertiary separator is a plurality of cooling fans.

[0007] Furthermore, the liquid absorption device also includes a water curtain wall arranged between the upper part of the collecting tank and the lower part of the flushing nozzle layer.

[0008] Furthermore, the water curtain wall is composed of a plurality of water curtain wall screens, and the aperture of each water curtain wall screen is 3 mm.

[0009] Furthermore, the dust recovery system of the urea granulation tower also includes a flushing water tank, which is connected to the circulation tank after a replenishing pump, and is connected to the liquid absorption device after a replenishing pump. The flushing water tank is connected to the desorption waste liquid of urea through a first pipeline.

[0010] Furthermore, the first pipeline is also connected to a bypass pipeline 1 and a bypass pipeline 2. The bypass pipeline 1 is used to access the steam condensate, and the bypass pipeline 2 is used to access the desalted water.

[0011] Furthermore, a flushing sink exhaust pipe is provided on the top of the flushing sink.

[0012] Furthermore, a flushing sink manhole is also provided on the top of the flushing sink.

[0013] Furthermore, at least one circulation tank exhaust pipe is provided on the circulation tank, and the circulation tank exhaust pipe is connected to the collecting tank.

[0014] Furthermore, a circulation tank manhole is also provided at the top of the circulation tank.

[0015] Furthermore, steam pipes 1 are connected to both sides of the circulation tank, and steam pipes 1 are used to introduce thermal insulation steam into the system.

[0016] Compared with the prior art, the utility model has the following beneficial effects:

[0017] 1. In the utility model, the dust-containing gas rising in the urea granulation tower rises through the liquid absorption device at the air outlet, and after fully contacting with the descending circulating absorption, the gas rises to the first separation section for separation, and the liquid descends into the collection tank. The particulate urea entrained in the hot air rising in the atomization zone fully contacts with the descending circulating absorption liquid, and then enters the separation section, and the entrained droplets are removed by secondary separation, and the condensed droplets in the saturated gas are removed by the last stage of separation, which fully solves the problem of absorption droplets being carried out of the tower, reduces the urea dust content discharged into the atmosphere, and meets environmental protection requirements.

[0018] 2. The water curtain wall of the utility model is arranged between the upper part of the collection tank and the lower part of the flushing nozzle layer. The aperture of the water curtain wall screen is 3mm, which increases the effective area of ​​the entire water curtain. After the nozzles of the three nozzle layers are turned on, the water curtain wall forms a water curtain, which absorbs the rising gas and increases the effect of gas recovery.

[0019] 3. The dust recovery system of the urea granulation tower of the utility model uses the desorption waste liquid of urea hydrolysis as spray water, which is recycled and finally recycled to the urea granulation tower for re-production. Not only can the desorption waste liquid be reused, a small amount of urea in it can be recovered, turning waste into treasure, but also the use of water resources can be saved, urea production can be increased, and production costs can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the dust recovery system of the urea granulation tower of the utility model.

[0021] Reference numerals:

[0022] 1-liquid absorption device; 101-water curtain wall; 102-atomizing nozzle; 103-filter; 104-drip atomizing nozzle; 105-cross-flow water trap; 106-flushing nozzle; 107-cooling fan; 2-collecting tank; 201-circulating downflow water channel; 3-circulating tank; 301-circulating tank manhole; 302-circulating tank exhaust pipe; 4-circulating pump; 5-flushing water tank; 51-flushing water tank exhaust pipe; 52-flushing water tank manhole; 6-liquid replenishing pump;

[0023] 7-first pipeline; 71-bypass pipeline one; 72-bypass pipeline two; 8-second pipeline; 9-third pipeline; 10-fourth pipeline; 11-fifth pipeline; 12-sixth pipeline; 121-bypass pipeline three; 13-seventh pipeline; 14-circulation tank overflow pipeline; 15-steam pipeline one; 16-steam pipeline two; 17-medium-pressure steam pipeline; 18-eighth pipeline; 19-ninth pipeline; 20-flushing tank overflow pipeline;

[0024] 21-first liquid level gauge; 22-first flow control valve; 23-second liquid level gauge; 24-second flow control valve; 25-steam control valve; 26-third flow control valve;

[0025] 27 - first filter; 28 - first stop valve; 29 - second filter; 30 - second stop valve; 31 - third filter. DETAILED DESCRIPTION

[0026] The technical solution of the utility model will be clearly described below in conjunction with the accompanying drawings. Obviously, the described embodiments are not all embodiments of the utility model. All other embodiments obtained by ordinary technicians in this field without making creative work are within the protection scope of the utility model.

[0027] It should be noted that the terms "center", "up", "down", "horizontal", "left", "right", "front", "back", "lateral", "longitudinal", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the utility model.

[0028] like Figure 1 As shown, the utility model provides a dust recovery system for a urea granulation tower, comprising a liquid absorption device 1 arranged at the air outlet at the top of the urea granulation tower, a collecting tank 2 arranged below the liquid absorption device 1, a circulation tank 3 arranged below the collecting tank 2 and connected to the collecting tank 2 through a circulating downcomer 201, a flushing water tank 5 connected to the circulation tank 3 and the liquid absorption device 1 through a liquid replenishment pump 6, and the circulation tank 3 is connected to the liquid absorption device 1 through a circulation pump 4.

[0029] During operation, the desorption waste liquid in the flushing water tank 5 is sent to the liquid absorption device 1 through the liquid replenishment pump 6, and liquid is added to the circulation tank 3. After reaching a certain liquid level, the liquid in the circulation tank 3 is sent to the liquid absorption device 1 through the circulation pump 4. The liquid absorption device 1 absorbs the dust-containing gas rising in the urea granulation tower through the principle of wet spray absorption, that is, the liquid and the dust-containing gas are countercurrently contacted to absorb, and the desorption waste liquid that absorbs the dust particles flows to the collecting tank 2, and then flows to the circulation tank 3 through the collecting tank 2 through the circulating downcomer waterway 201. The desorption waste liquid that absorbs the dust particles is sent to the liquid absorption device 1 through the circulation tank 3 through the circulation pump 4, and circulates continuously to recover dust.

[0030] The liquid absorption device 1 includes three nozzle layers, which are the first atomizing nozzle layer, the second atomizing nozzle layer and the flushing nozzle layer from bottom to top. The first atomizing nozzle layer is composed of a plurality of atomizing nozzles 102 arranged upward, and the second atomizing nozzle layer is composed of a plurality of dripping atomizing nozzles 104 arranged upward. The desorption waste liquid sprayed by the atomizing nozzles 102 and the dripping atomizing nozzles 104 is atomized and fully contacts with the urea dust. The flushing nozzle layer is composed of a plurality of flushing nozzles 106, which recovers the urea dust, flushes the urea crystals in the liquid absorption device 1, and adds liquid to the circulation tank 3.

[0031] The liquid absorption device 1 also includes a primary separator arranged between the first atomizing nozzle layer and the second atomizing nozzle layer, a secondary separator arranged between the second atomizing nozzle layer and the flushing nozzle layer, and a tertiary separator arranged above the flushing nozzle layer. Among them, the primary separator is a filter 103, which is used to remove the rising droplets and separate the droplets in the rising gas; the secondary separator is a cross-flow water trap 105, which is used to further remove the rising droplets and separate the droplets in the rising gas. The dust-containing gas rising in the urea granulation tower contacts with the descending circulating absorption liquid, and after being separated by the primary separator and the secondary separator, the liquid descends into the collection tank 2. The tertiary separator is a plurality of cooling fans 107. The air cooler 107 is usually in a closed state. When the temperature is high, the resistance of the recovery system increases. When the exhaust volume affects the temperature of the urea product at the bottom of the tower, the air cooler 107 at the top can be selectively turned on. Finally, the dust-containing gas enters the three-stage separator with low resistance. The air cooler 107 separates the absorption liquid containing urea dust and the rising gas, which increases the distribution, separation and absorption effect of the gas. The entrained droplets are removed through three separations, and the condensed droplets in the saturated gas are removed through the last stage of separation, which fully solves the problem of absorption droplets being carried out of the tower.

[0032] The liquid absorption device 1 also includes a water curtain wall 101, which is arranged between the upper part of the collection tank 2 and the lower part of the flushing nozzle layer. The water curtain wall 101 is composed of 300 water curtain wall screens, and the aperture of the water curtain wall screen is changed from the original 5mm to 3mm, thereby increasing the effective area of ​​the water curtain. After the nozzles of the three nozzle layers are turned on, the water curtain wall 101 forms a water curtain, which absorbs the rising gas and increases the effect of gas recovery.

[0033] Specifically, the inlet of the flushing tank 5 is connected to a first pipe 7, which is used to receive the desorption waste liquid, and the desorption waste liquid is used as the absorption liquid for recycling in the dust recovery system of the entire urea granulation tower; a gate valve is provided on the first pipe 7. The first pipe 7 is also connected to a bypass pipe 1 71 and a bypass pipe 2 72, and the bypass pipe 1 71 is used to receive steam condensate, and the bypass pipe 2 72 is used to receive desalted water, and gate valves are provided on the bypass pipe 1 71 and the bypass pipe 2 72. If the desorption waste liquid is unqualified, desalted water and steam condensate can be switched.

[0034] A flushing tank exhaust pipe 51 is provided at the top of the flushing tank 5 to exhaust the bubbles inside the flushing tank 5. A flushing tank manhole 52 is also provided at the top of the flushing tank 5 to allow personnel to enter and exit during maintenance.

[0035] The flushing tank 5 is also connected to a first liquid level gauge 21, which is also electrically connected to a controller (controller Figure 1 The first liquid level meter 21 is electrically connected to the first flow regulating valve 22 provided on the first pipeline 7, and the first flow regulating valve 22 is electrically connected to the controller. After the first liquid level meter 21 feeds back the detected liquid level of the flushing water tank 5 to the controller, the controller controls the opening of the first flow regulating valve 22 to ensure that the liquid level in the flushing water tank 5 is at the required liquid level. The flushing water tank 5 is also connected to a thermometer for measuring the temperature of the liquid in the flushing water tank 5.

[0036] The bottom of the flushing water tank 5 is connected to the flushing nozzle layer through the second pipe 8. A replenishing pump 6 is provided on the second pipe 8 near the flushing water tank 5. The desorption waste liquid in the flushing water tank 5 is sent to the flushing nozzle layer through the replenishing pump 6. Multiple flushing nozzles 106 spray the desorption waste liquid to the liquid absorption device 1, which plays multiple functions such as washing, absorption, separation, system liquid addition, and ensuring the tower hot pressure head. The top of the flushing water tank 5 is connected to the second pipe 8 through the third pipe 9. When the desorption waste liquid of the flushing water tank 5 overflows, it flows into the third pipe 9 and then into the second pipe 8 to participate in the aforementioned cycle.

[0037] The flushing water tank 5 is connected to the left side of the circulation tank 3 through the fourth pipe 10 after passing through the replenishment pump 6, and the second pipe 8 is connected to the right side of the circulation tank 3 through the fifth pipe 11 after passing through the replenishment pump 6, so that the desorbed waste liquid in the flushing water tank 5 is directly sent into the circulation tank 3 through the replenishment pump 6, and the circulation tank 3 is directly replenished.

[0038] A second flow regulating valve 24 is provided on the fourth pipeline 10 near the circulation tank 3, a second liquid level meter 23 is connected to the circulation tank 3, the second liquid level meter 23 is also electrically connected to the controller, the second liquid level meter 23 is electrically connected to the second flow regulating valve 24, and the second flow regulating valve 24 is electrically connected to the controller. After the second liquid level meter 23 feeds back the detected liquid level of the circulation tank 3 to the controller, the controller controls the opening of the second flow regulating valve 24, thereby ensuring that the liquid level in the circulation tank 3 is at the required liquid level.

[0039] The circulation tank 3 is connected to the second atomizing nozzle layer through the sixth pipeline 12. A circulation pump 4 with one open and one standby is arranged on the sixth pipeline 12 near the circulation tank 3. The desorption waste liquid in the circulation tank 3 is sent to the second atomizing nozzle layer through the circulation pump 4. A plurality of dripping atomizing nozzles 104 spray the desorption waste liquid toward the liquid absorption device 1.

[0040] A bypass pipe 3 121 is arranged between the sixth pipe 12 and the second pipe 8 close to the flushing nozzle layer. A normally closed valve is provided on the bypass pipe 3 121. By opening and closing the bypass pipe 3 121, the liquid in the circulation tank 3 can also enter the flushing nozzle layer, so that the flushing nozzle 106 sprays and atomizes the urea dust to be atomized and absorbed.

[0041] Two groups of normally open gate valves are arranged in parallel on the sixth pipeline 12 near the second atomizing nozzle layer, each group has two gate valves, and the middle nodes of the two gate valves are connected to the first atomizing nozzle layer, so that the desorbed waste liquid in the circulation tank 3 can enter the first atomizing nozzle layer and the second atomizing nozzle layer at the same time after the circulation pump 4, and the atomizing nozzle 102 can also spray and atomize the urea dust for atomization absorption. And the pipelines at the entrances of the first atomizing nozzle layer and the second atomizing nozzle layer are one open and one standby.

[0042] The circulation tank 3 is connected to the underground tank and urine tank of the urea granulation tower through the circulation pump 4 through the seventh pipeline 13. When the concentration of the absorption liquid in the circulation tank 3 rises to a certain value, it is detected by the concentration meter set on the circulation tank 3, and then the circulating absorption liquid is controlled and adjusted by the third flow regulating valve 26 to be recovered to the urine tank and participate in granulation again; when the urine concentration in the circulation tank 3 does not meet the standard, it is switched to the underground tank of the urea granulation tower, and sent to the ammonia tank of the urea granulation tower through the underground tank, and finally to the urea analysis and hydrolysis system for recovery. The top of the circulation tank 3 is connected to the underground tank and the urine tank through the circulation tank overflow pipeline 14. Under abnormal circumstances, the circulating absorption liquid is sent to the underground tank or urine tank through the circulation tank overflow pipeline 14.

[0043] At least one circulation tank exhaust pipe 302 is provided on the circulation tank 3, and the circulation tank exhaust pipe 302 leads to the collection tank 2, and is used to exhaust the bubbles in the circulation tank 3 and return them to the liquid absorption device 1 for recycling. A circulation tank manhole 301 is also provided on the top of the circulation tank 3 for personnel to enter and exit during maintenance.

[0044] The left side of the circulation tank 3 is also connected to a steam pipe 15, from which the system heat preservation steam is introduced to heat the circulation tank 3. A steam regulating valve 25 is provided on the steam pipe 15. During the absorption process of the circulating absorption liquid, the temperature of the circulating absorption liquid continues to drop due to the heat absorption of urea dissolution and the effect of the cold air at the top of the tower. The heating of the circulation tank 3 is controlled by controlling the opening of the steam regulating valve 25, so that the temperature of the circulation tank 3 is stably controlled at 30-40°C, preferably without causing crystallization.

[0045] The fifth pipe 11 on the right side of the circulation tank 3 is connected to the second steam pipe 16, and the system heat preservation steam is introduced from the second steam pipe 16 to heat the liquid absorption device 1, the circulation tank 3 and other pipes at the same time. The circulation tank 3 is also connected to a thermometer for measuring the temperature of the liquid in the circulation tank 3. The left side of the circulation tank 3 is also connected to a medium-pressure steam pipe 17, and medium- and low-pressure steam is introduced from the medium-pressure steam pipe 17 to heat the circulation tank 3.

[0046] The circulation tank 3 is connected to an underground tank or a urine tank via an eighth pipeline 18. When the liquid level in the circulation tank 3 reaches a required height, the absorption liquid can be directly sent to the underground tank or the urine tank.

[0047] The flushing water tank 5 is connected to the underground tank and the urine tank through the ninth pipeline 19 after the liquid replenishment pump 6, and then when the liquid level in the flushing water tank 5 reaches the required height, the desorption waste liquid is sent to the underground tank or the urine tank through the liquid replenishment pump 6. The flushing water tank 5 is also provided with a flushing water tank overflow pipeline 20, which is used to discharge the liquid in the flushing water tank 5 when it overflows.

[0048] In addition, a first filter 27 is provided at the inlet of the fluid replenishment pump 6. The first filter 27 adopts a conical filter. The desorption waste liquid of the flushing water tank 5 enters the fluid replenishment pump 6 after being filtered by the first filter 27. The desorption waste liquid that does not pass through the first filter 27 is discharged to the underground tank through the first stop valve 28.

[0049] A second filter 29 is provided at the inlet of the circulation pump 4. The second filter 29 is a conical filter. The liquid in the circulation tank 3 enters the circulation pump 4 after being filtered by the second filter 29. The liquid that does not pass through the second filter 29 is discharged to the underground tank through the second stop valve 30 on its pipeline.

[0050] A third filter 31 is provided at the water inlet of the second atomizing nozzle layer of the liquid absorption device 1. The third filter 31 adopts a T-shaped filter. The liquid passing through the circulation pump 4 enters the liquid absorption device 1 after being filtered by the third filter 31. The liquid that does not pass through the third filter 31 is discharged to the underground tank through the gate valve on its pipeline.

[0051] Working process:

[0052] Air flow in the dust recovery system of the urea granulation tower:

[0053] At the beginning, the desorption waste liquid in the flushing tank 5 is passed into the upper flushing nozzle 106 through the liquid replenishing pump 6 to add the desorption waste liquid to the system;

[0054] When the liquid level of the circulation tank 3 is half filled, the circulation pump 4 is turned on to fill the two layers of atomizing nozzles, the atomizing nozzle 102 and the dripping atomizing nozzle 104 spray liquid to form a two-layer water curtain wall absorption zone;

[0055] The dust-containing gas rising in the urea granulation tower passes through the channels on both sides above the collecting tank 2, passes through the two-layer water curtain wall absorption area, and after two stages of atomization absorption, enters the filter 103 to separate the droplets;

[0056] Then, after being atomized and absorbed by the dripping atomizing nozzle 104 of the second atomizing nozzle layer, it enters the cross-flow water mist collector 105 for liquid separation, and the saturated gas after the droplets are removed enters the third-level separation space;

[0057] In the three-stage separation space, the liquid droplets containing urea particles are further condensed by mixing with the peripheral cold air from the cooling fan 107 coming in through the ventilation window;

[0058] Finally, it is discharged after three-stage separation.

[0059] The particulate urea entrained in the rising hot air in the atomization zone fully contacts with the descending circulating absorption liquid, and then enters the separation section. The entrained droplets are removed through secondary separation, and the condensed droplets in the saturated gas are removed through the last stage of separation, which fully solves the problem of absorption droplets being carried out of the tower.

[0060] Liquid flow in the dust recovery system of the urea granulation tower:

[0061] The desorption waste liquid of urea is sent to the flushing water tank 5, and the liquid replenishing pump 6 sends the desorption waste liquid in the flushing water tank 5 to the flushing nozzle 106, and the flushing nozzle 106 sprays and atomizes the waste liquid for preliminary absorption and liquid addition;

[0062] The absorption liquid flows to the collecting tank 2, flows to the circulation tank 3 through the circulating downcomer 201, and after flowing out of the circulation tank 3, it is filtered through the second filter 29, and then sent to the atomizing nozzle 102 and the dripping atomizing nozzle 104 through the circulation pump 4, and then flows back to the circulation tank 3 again.

[0063] The utility model adopts the principle of wet spray absorption (liquid and dust-containing gas are in countercurrent contact for absorption), and utilizes the desorbed waste liquid or process condensate (temperature 119°C) to be pressurized and atomized by a circulating pump, and fully contacted with urea dust for a long time. The formed droplets are separated by a gas-liquid separator and enter the circulating liquid. The circulating liquid reaches a certain concentration (urea content 10%) and is recycled into the urea production system. The liquid loss of the circulating evaporation and replenishment system is replenished by fresh process condensate. The gas-liquid contact part is a combination of water curtain absorption, water film absorption, high-efficiency separation and cooling separation for dust removal, thereby meeting the national environmental protection emission requirements. The recovered liquid is then fed into the urea system for evaporation and granulation, which not only solves the environmental protection problem, but also achieves cost reduction and efficiency improvement.

[0064] The above technical features constitute the best implementation example of the present utility model, which has strong adaptability and best implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the needs of different situations.

[0065] Finally, it should be noted that the above content is only used to illustrate the technical solution of the utility model, rather than to limit the protection scope of the utility model. Simple modifications or equivalent substitutions of the technical solution of the utility model by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the utility model.

Claims

1. A dust recovery system for a urea granulation tower, comprising a liquid absorption device arranged at the air outlet at the top of the urea granulation tower, a collecting tank is arranged below the liquid absorption device, a circulating tank is arranged below the collecting tank, the collecting tank is connected to the circulating tank through a circulating downcomer, and the circulating tank is connected to the liquid absorption device through a circulating pump, characterized in that: The liquid absorption device includes a first atomizing nozzle layer, a second atomizing nozzle layer and a flushing nozzle layer which are arranged in sequence from bottom to top; a primary separator is arranged between the first atomizing nozzle layer and the second atomizing nozzle layer, a secondary separator is arranged between the second atomizing nozzle layer and the flushing nozzle layer, and a third-stage separator is arranged above the flushing nozzle layer, and the third-stage separator is a plurality of cooling fans.

2. The dust recovery system of the urea granulation tower according to claim 1, characterized in that: The liquid absorption device also includes a water curtain wall arranged between the upper part of the collecting tank and the lower part of the flushing nozzle layer.

3. The dust recovery system of the urea granulation tower according to claim 2, characterized in that: The water curtain wall is composed of several water curtain wall screens, and the aperture of each water curtain wall screen is 3mm.

4. The dust recovery system of the urea granulation tower according to any one of claims 1 to 3, characterized in that: The dust recovery system of the urea granulation tower also includes a flushing water tank, which is connected to the circulation tank through a replenishing pump, and is connected to the liquid absorption device through a replenishing pump. The flushing water tank is connected to the desorption waste liquid of urea through a first pipeline.

5. The dust recovery system of the urea granulation tower according to claim 4, characterized in that: The first pipeline is also connected with a bypass pipeline 1 and a bypass pipeline 2. The bypass pipeline 1 is used for receiving steam condensate, and the bypass pipeline 2 is used for receiving desalted water.

6. The dust recovery system of the urea granulation tower according to claim 4, characterized in that: A flushing sink exhaust pipe is arranged on the top of the flushing sink.

7. The dust recovery system of the urea granulation tower according to claim 6, characterized in that: A flushing sink manhole is also provided on the top of the flushing sink.

8. The dust recovery system of the urea granulation tower according to any one of claims 1 to 3, characterized in that: At least one circulation tank exhaust pipe is arranged on the circulation tank, and the circulation tank exhaust pipe is communicated with the collecting tank.

9. The dust recovery system of the urea granulation tower according to claim 8, characterized in that: A circulation tank manhole is also provided on the top of the circulation tank.

10. The dust recovery system of the urea granulation tower according to claim 8, characterized in that: Steam pipes 1 are also connected to both sides of the circulation tank, and steam pipes 1 are used to introduce system insulation steam.

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