Tower type cyclone water film pickling device

Abstract

The utility model provides a tower type cyclone water film pickling device which comprises a spray washing unit, a cyclone water film washing unit and a recovery tank from top to bottom, and a clean tail gas outlet is formed in the top of the spray washing unit; the cyclone water film washing unit comprises a barrel, and the lower end of the barrel is provided with a washing liquid outlet and is connected with an upper port of a recovery tank provided with a recovery tank liquid inlet through a flange; a volute pipe inlet for introducing tail gas is welded on the outer cylinder wall of the cylinder body, a volute pipe is arranged in the cylinder body in a rotary rising manner, and a volute pipe outlet extends to an upper port of the cylinder body provided with a gas phase outlet; a liquid collecting cavity with an annular cavity and a liquid supplementing opening is formed in the outer wall of the top of the barrel, and a liquid collecting plate and an overflow area are arranged in the liquid collecting cavity from top to bottom; the lower end of the recovery tank is provided with a recovery tank liquid outlet connected with a circulating pump. The device effectively removes urea dust and free ammonia in the tail gas, and is environment-friendly, low in energy consumption, high in recovery efficiency and stable in operation.

Description

Technical Field

[0001] The utility model relates to the field of large-particle urea production, in particular to a tower-type cyclone water film acid washer. Background Art

[0002] According to actual production experience, the dust generated by the large-particle urea device mainly comes from equipment such as granulators, crushers and vibrating screens, and the dust generated in the granulation section accounts for more than 50% of the total dust in the device. This part of the granulation tail gas containing a large amount of urea dust is pumped to the wet scrubber through the outlet at the top of the granulator. The scrubber is equipped with multiple nozzles and trays. The desalted water sprayed by the nozzle cools and washes the granulation tail gas. The urea dust in the tail gas is dissolved in the desalted water and collected at the bottom of the scrubber. It is sent to the evaporation section through a delivery pump as a recovered urea solution. The washed tail gas is sent to the chimney through an induced draft fan for discharge. However, the washing technology currently used still has many problems: the traditional wet scrubber sprays desalted water through the nozzle to form water mist to contact the tail gas in reverse, thereby washing the urea dust and free ammonia in the tail gas, but due to factors such as short residence time, small contact area, and large influence of air volume and wind speed, the washing effect is limited, and the urea dust in the tail gas cannot be stably removed, and it is difficult to meet the emission requirements. At the same time, since the partial pressure of free ammonia in the tail gas is very low, the absorption of free ammonia by water washing is limited. Data show that the concentration of free ammonia in the tail gas after water washing still reaches 70~80mg / m 3 Around, far from 30mg / m 3 emission requirements.

[0003] In order to improve the shortcomings of existing washing technology, Chinese patent CN220531088U discloses a large-particle urea tail gas dust treatment and recovery device, which redesigns the traditional wet scrubber and adds a preliminary washing device before the tail gas enters the scrubber, the purpose of which is to pre-clean the tail gas and fully mix the gas, liquid and solid phases. At the same time, multiple groups of spray devices and filler demisters are designed in the scrubber, the purpose of which is to increase the contact area and residence time of the gas-liquid two phases, so that the dissolution of urea dust in the tail gas is more thorough, and to a certain extent solves the problem of substandard washing effect of traditional scrubbers. However, due to the large number of internal parts of the scrubber, including multi-stage fillers and demisters, its pressure drop is significantly increased, which greatly increases the load of the induced draft fan and has high energy consumption; and its principle is still to use a water washing method, which cannot reduce the free ammonia in the tail gas to a level that meets the emission standards. Chinese patent CN219072556U discloses a fluidized bed granulator tail gas purification device, which is mainly composed of an ammonia removal device, a purification device, an induced draft fan, and an exhaust gas emission device in sequence. The ammonia removal device neutralizes and absorbs free ammonia in the tail gas by dilute acid spraying. The tail gas after ammonia removal enters the purification device, and the dust is adsorbed and purified by a dry process. The collected dust is collected in the ash hopper for dissolution and recovery. This method effectively solves the problem that free ammonia in the tail gas is difficult to remove, and urea dust is collected by adsorption and catalytic oxidation methods, so that the discharged tail gas meets national standards. However, in this method, the ammonia removal device will continue to produce dilute ammonium salts, which requires further steps to be added for treatment, increasing costs; and the packing tower is used to physically adsorb urea dust, and the packing layer is easily blocked, which needs to be cleaned and replaced regularly, reducing the stability of the device and increasing operating costs. In addition, the multi-stage packing layer also greatly increases the pressure drop of the equipment, increases the burden of the induced draft fan, and has high energy consumption.

[0004] In view of this, the present utility model is proposed. Utility Model Content

[0005] In order to solve the above technical problems, the utility model provides a tower cyclone water film acid washer, which not only effectively removes urea dust and free ammonia in the exhaust gas, so that the exhaust gas meets the environmental protection requirements of the industry and reaches the emission standards, but also has high recovery efficiency, stable operation and low energy consumption.

[0006] A tower cyclone water film acid washer, comprising a spray washing unit, a cyclone water film washing unit and a recovery tank from top to bottom, wherein a clean tail gas outlet is provided at the top of the spray washing unit;

[0007] The cyclone water film washing unit includes a cylinder, the lower end of which is provided with a washing liquid outlet and is connected to the upper port of the recovery tank where the recovery tank inlet is provided through a flange; a volute inlet for introducing exhaust gas is welded on the outer cylinder wall of the cylinder, the volute rotates and rises inside the cylinder, and the volute outlet extends to the upper port of the cylinder where the gas phase outlet is provided; a liquid collecting chamber with an annular cavity and a liquid replenishing port is provided on the top outer wall of the cylinder, and a liquid collecting plate and an overflow area are provided in the liquid collecting chamber from top to bottom; a recovery tank liquid outlet connected to a circulating pump is provided at the lower end of the recovery tank.

[0008] As a mode, the scroll inlet and the scroll outlet are both arranged along a direction tangent to the cylinder.

[0009] As a method, the overflow area is provided with a plurality of circles of evenly arranged overflow holes, and the overflow holes are circular holes opening obliquely upward.

[0010] As a method, the spray washing unit is arranged from bottom to top as an air inlet, a first-level spray device, a first-level tower plate, a second-level spray device, a second-level tower plate, a dilute acid liquid replenishment spray device, a demister and a clean exhaust gas outlet; the first-level spray device and the second-level spray device are respectively connected to the outlet of the circulation pump, and the dilute acid liquid replenishment spray device is connected to an external dilute acid liquid replenishment storage device.

[0011] As a method, the angle between the tube path of the volute and the central axis of the cylinder is 0-15°.

[0012] As one method, the liquid collecting plate is a circular plate with an opening in the middle for the exhaust gas to pass through and with four sides inclined downward.

[0013] As one mode, the recovery tank is in an inverted cone structure, the upper end of the inverted cone structure is set as the liquid inlet of the recovery tank, and the lower end of the inverted cone structure is set as the liquid outlet of the recovery tank.

[0014] As one approach, the overflow area is composed of multiple circles of overflow holes arranged at an opening distance of 2 to 4 cm.

[0015] As a method, the overflow hole has an inclination angle of 30°~45° relative to the vertical direction.

[0016] The utility model has the following beneficial effects:

[0017] 1. The tower cyclone water film acid washer of the utility model can effectively remove urea dust and free ammonia in the tail gas of large-particle urea granulation, and at the same time reduce the water vapor content in the tail gas, so that the final exhaust gas reaches the industry standard, and realizes the purpose of clean and environmentally friendly exhaust gas emission and preventing environmental pollution.

[0018] 2. The tower cyclone water film acid washer of the utility model is designed by adopting the washing principle combining cyclone water film washing and spray washing, and can deeply remove urea dust and free ammonia in the tail gas of large-particle urea.

[0019] 3. The tower-type cyclone water film acid washer of the utility model can collect the washing liquid of the spray washing unit and serve as the source of the water film formed by the cyclone water film washing unit, thereby improving the utilization rate of the washing liquid and reducing energy consumption.

[0020] 4. The tower cyclone water film pickling device of the utility model has a simple structure, stable operation, and low maintenance cost. At the same time, the equipment has a small pressure drop, a small exhaust gas induced draft fan load, and low energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings are used to provide a further understanding of the technical solution of the utility model and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the utility model and do not constitute a limitation on the technical solution of the utility model.

[0022] Figure 1 It is a schematic structural diagram of the tower cyclone water film pickling device described in the utility model.

[0023] Figure 2 yes Figure 1 Schematic diagram of the partial structure of the middle volute inlet.

[0024] Explanation of reference numerals: 1-recovery tank, 11-recovery tank inlet, 12-recovery tank outlet, 2-cyclone water film washing unit, 21-washing liquid outlet, 22-volute tube inlet, 23-cylinder, 24-liquid collecting chamber, 25-liquid replenishing port, 26-overflow area, 27-liquid collecting plate, 28-gas phase outlet, 3-spray washing unit, 31-air inlet, 32-first-stage spraying device, 33-first-stage tower plate, 34-second-stage spraying device, 35-second-stage tower plate, 36-dilute acid replenishing spraying device, 37-demister, 38-clean exhaust gas outlet, 4-density meter, 5-pH meter, 6-circulation pump, 7-induced draft fan. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution of the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings of the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Based on the described embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0026] Example 1

[0027] A tower cyclone water film pickling device, such as Figure 1 As shown, it is divided into three parts: upper, middle and lower, that is, the spray washing unit 3, the cyclone water film washing unit 2 and the recovery tank 1 are arranged in sequence from top to bottom; the top of the spray washing unit 3 is provided with a clean exhaust gas outlet 38. The clean exhaust gas outlet 38 is connected to the induced draft fan 7 to discharge it into the atmosphere.

[0028] The cyclone water film washing unit 2 comprises a washing liquid outlet 21 , a volute inlet 22 , a cylinder 23 , a liquid collecting chamber 24 , a liquid replenishing port 25 , an overflow area 26 , a liquid collecting plate 27 and a gas phase outlet 28 .

[0029] The washing liquid outlet 21 is arranged at the lower end of the cylinder 23 , and the lower end of the cylinder 23 is connected to the upper end of the recovery tank 1 through a flange, and the upper end of the recovery tank 1 is provided with a recovery tank liquid inlet 11 .

[0030] like Figure 2 As shown, the volute inlet 22 is welded to the outer wall of the cylinder 23, the volute inlet 22 and the volute outlet (not marked) are tangent to the cylinder 23, the volute tube path is at a certain angle to the cylinder 23, and the specific optional angle is 0~15° (excluding 0°), and the exhaust gas enters the cylinder 23 tangentially from the volute inlet 22 and rotates upward.

[0031] As a specific example, the aspect ratio of the cylinder 23 is 1:5-6.

[0032] The liquid collecting chamber 24 is installed on the outer wall of the top of the cylinder 23, and has a cylindrical structure in appearance. The top plate and the bottom plate of the liquid collecting chamber 24 are connected to the outer wall of the cylinder 23 to form an annular cavity. The liquid collecting chamber 24 is provided with a liquid replenishing port 25, which is connected to the circulation pump 6, and can send the supplementary washing liquid sent by the circulation pump 6 into the liquid collecting chamber 24.

[0033] An overflow area 26 is provided inside the liquid collecting chamber 24, and the overflow area 26 is composed of overflow holes arranged at a certain distance. The overflow hole is a circular hole that opens obliquely upward to ensure that a layer of water film is formed on the wall of the cylinder 23 when the washing liquid overflows from the overflow hole. The liquid collecting plate 27 is arranged above the overflow area 26. The gas phase outlet 28 is arranged at the upper end of the cylinder 23, and the upper end of the cylinder 23 is connected to the lower end of the spray washing unit 3 through a flange, so that the gas from the cyclone water film washing unit 2 enters the spray washing unit 3.

[0034] Specifically, the liquid collecting plate 27 is a circular plate with an opening in the middle for the exhaust gas to pass through (as a specific example, the diameter of the opening is 1 / 2 of the diameter of the cylinder of the cyclone water film washing unit) and a downwardly inclined annular plate (the inclination angle relative to the horizontal direction can be preferably 5-15°). Under the action of gravity, the collected washing liquid is continuously sent into the liquid collecting chamber 24 as the source of the water film washing liquid formed by the cyclone water film washing unit 2.

[0035] As an example, the overflow area 26 is composed of multiple circles of overflow holes arranged at an opening distance of 2 to 4 cm, preferably 2 to 3 circles of overflow holes are arranged. Further, the overflow holes are circular holes with an upward inclination angle of 30° to 45° (relative to the vertical direction).

[0036] When the equipment is running stably, the washing liquid in the liquid collecting chamber 24 continuously overflows from the overflow area 26 to the inner wall of the cylinder 23, and forms a water film flowing downward along the inner wall of the cylinder 23 under the action of gravity. After the exhaust gas enters the cyclone water film washing unit 2, due to the action of centrifugal force, the urea dust particles in the exhaust gas are thrown to the cylinder wall, and then adhered to the water film and left along the cylinder wall. The washing liquid enters the lower recovery tank 1 for buffering and collection.

[0037] The recovery tank 1 is an inverted cone structure, the upper end of the inverted cone structure is set as the recovery tank liquid inlet 11 and is directly connected to the washing liquid outlet 21 of the cyclone water film washing unit 2 through a flange, and the recovery tank liquid outlet 12 set at the lower end of the inverted cone structure is connected to the circulation pump 6 through a pipeline. A density meter 4 and a pH meter 5 are installed at the inlet of the circulation pump 6 to monitor the density and pH value of the circulating liquid in real time, and these data are used to control the direction of the circulating liquid in the recovery tank 1 and whether to open the dilute acid replenishment pipeline.

[0038] The tower type cyclone water film pickling device of the utility model does not need to be provided with a packing layer, has a low relative pressure drop, a small load of the induced draft fan 7, low energy consumption, and is equally effective in dust removal and ammonia removal. The spray washing unit 3 and the cyclone water film washing unit 2 are respectively connected to the outlet of the circulation pump 6, so that the circulating liquid is sent into the cyclone water film pickling device at a stable pressure for circulation, which is energy-saving and environmentally friendly.

[0039] As a specific example, the spray washing unit 3 is respectively provided with an air inlet 31, a primary spray device 32, a primary tray 33, a secondary spray device 34, a secondary tray 35, a dilute acid liquid replenishment spray device 36, a demister 37 and a clean tail gas outlet 38 from bottom to top. The outlet of the circulation pump 6 is connected to the liquid replenishment port 25, the primary spray device 32 and the secondary spray device 34 through three pipelines.

[0040] The tail gas after dust removal by the cyclone water film washing unit 2 enters the spray washing unit 3 through the air inlet 31. The primary spray device 32 (with multiple nozzles) and the secondary spray device 34 (with multiple nozzles) are supplied with acidic washing liquid by the circulating pump 6. The nozzles atomize the acidic washing liquid into fine water droplets. The tail gas contacts the acidic water mist in countercurrent upward. The free ammonia in the tail gas reacts with the acid in the water mist and is continuously separated and removed. The washing liquid collected on the primary tray 33 and the secondary tray 35 forms a layer of liquid film, which further expands the contact area between the ammonia-containing tail gas and the acidic washing liquid, and performs sufficient adsorption and neutralization.

[0041] The dilute acid replenishment spray device 36 is connected to an external dilute acid replenishment storage device, and the dilute acid replenishment can be selected from dilute nitric acid, dilute sulfuric acid or organic acid (formic acid), etc. When the pH meter 5 monitors that the pH value reaches 5.5-6, the DCS system controls the opening of the dilute acid replenishment spray device 36 on the top of the spray washing unit 3 to replenish acid until the pH value reaches 2-3.

[0042] As an optional solution, the outlet of the circulation pump 6 is provided with a three-way valve, which is further connected to the external evaporation unit. The DCS system monitors and analyzes the pH value and density value in real time and controls the switching of the valve. When the density meter 4 detects that the urea in the circulating liquid coming out of the recovery tank 1 reaches a certain density, the valve is switched to pump the circulating liquid to the evaporation unit to recycle the urea. For example, the density reaches 1.11~1.15g / cm 3 When the three-way valve after the recovery pump 6 is switched, the washing liquid is sent to the evaporation unit.

[0043] The important working process of the tower cyclone water film pickling device of the utility model is analyzed and explained below:

[0044] The exhaust gas enters the cylinder 23 tangentially from the volute inlet 22 of the cyclone water film washing unit 2, and rotates upward. Due to the centrifugal force, the urea dust particles in the exhaust gas are thrown to the cylinder wall, and then adhered by the water film, left along the cylinder wall, and enter the lower recovery tank 1 for collection and buffering.

[0045] The tail gas after dust removal by the cyclone water film washing unit 2 enters the spray washing unit 3 upwards, and the primary spray device 32 and the secondary spray device 34 are supplied with acidic washing liquid by the circulating pump 6. The nozzles of the primary spray device 32 and the secondary spray device 34 atomize the acidic washing liquid into fine water droplets, and the tail gas contacts the acidic water mist in countercurrent upwards, and the free ammonia in the tail gas reacts with the acid, and is fully adsorbed and neutralized on the primary tray 33 and the secondary tray 35. When the pH meter 5 on the bottom pipeline of the pickling device detects that the pH of the circulating acidic washing liquid reaches 5.5~6, the dilute acid replenishment spray device 36 at the top of the spray washing unit 3 is automatically controlled by the DCS system to open, so as to enhance the ability of the circulating liquid in the system to absorb free ammonia. The tail gas after ammonia removal continues to go upwards and passes through the top demister 37 for demisting and dehydration, and then reaches the emission standard. The tail gas that meets the standard is pumped by the induced draft fan 7 from the clean tail gas outlet 38 at the top of the cyclone water film pickling device and discharged into the atmosphere. The final exhaust gas emissions meet industry standards, achieving the goal of clean and environmentally friendly exhaust gas emissions and preventing environmental pollution.

[0046] The washing liquid sprayed from top to bottom by the spray washing unit 3 enters downward into the cyclone water film washing unit 2 , is collected by the liquid collecting plate 27 , and enters into the liquid collecting chamber 24 .

[0047] Although the implementation methods disclosed in the utility model are as above, the above contents are only implementation methods adopted to facilitate the understanding of the utility model, and are not used to limit the utility model. Any technician in the field to which the utility model belongs can make any modifications and changes in the form and details of implementation without departing from the spirit and scope disclosed in the utility model, but the scope of patent protection of the utility model shall still be based on the scope defined in the attached claims.

Claims

1. A tower cyclone water film pickling device, comprising a spray washing unit, a cyclone water film washing unit and a recovery tank from top to bottom, wherein the top of the spray washing unit is provided with a clean exhaust gas outlet; It is characterized in that The cyclone water film washing unit includes a cylinder, the lower end of which is provided with a washing liquid outlet and is connected to the upper port of the recovery tank where the recovery tank inlet is provided through a flange; a volute inlet for introducing exhaust gas is welded on the outer cylinder wall of the cylinder, the volute rotates and rises inside the cylinder, and the volute outlet extends to the upper port of the cylinder where the gas phase outlet is provided; a liquid collecting chamber with an annular cavity and a liquid replenishing port is provided on the top outer wall of the cylinder, and a liquid collecting plate and an overflow area are provided in the liquid collecting chamber from top to bottom; a recovery tank liquid outlet connected to a circulating pump is provided at the lower end of the recovery tank.

2. The tower cyclone water film pickling device according to claim 1 is characterized in that: The volute inlet and the volute outlet are both arranged along a direction tangent to the cylinder.

3. The tower cyclone water film pickling device according to claim 1 is characterized in that: The overflow area is provided with a plurality of circles of evenly arranged overflow holes, and the overflow holes are circular holes opening obliquely upward.

4. The tower cyclone water film pickling device according to claim 1 is characterized in that: The spray washing unit is provided with an air inlet, a first-level spray device, a first-level tower plate, a second-level spray device, a second-level tower plate, a dilute acid liquid replenishment spray device, a demister and a clean exhaust gas outlet from bottom to top; the first-level spray device and the second-level spray device are respectively connected to the outlet of the circulation pump, and the dilute acid liquid replenishment spray device is connected to an external dilute acid liquid replenishment storage device.

5. The tower cyclone water film pickling device according to claim 2 is characterized in that: The angle between the tube path of the volute and the central axis of the cylinder is 0-15°.

6. The tower cyclone water film pickling device according to claim 1, characterized in that: The liquid collecting plate is a circular plate with an opening in the middle for tail gas to pass through and four sides inclined downward.

7. The tower cyclone water film pickling device according to claim 1, characterized in that: The recovery tank is in an inverted cone structure, the upper end of the inverted cone structure is set as the liquid inlet of the recovery tank, and the lower end of the inverted cone structure is set as the liquid outlet of the recovery tank.

8. The tower cyclone water film pickling device according to claim 3 is characterized in that: The overflow area is composed of multiple circles of overflow holes arranged at an opening distance of 2 to 4 cm.

9. The tower cyclone water film pickling device according to claim 3 or 8, characterized in that: The overflow hole has an inclination angle of 30° to 45° relative to the vertical direction.

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