Urea saturation dissolving device

Abstract

The utility model belongs to the technical field of urea dissolution, and particularly relates to a urea saturation dissolution device which comprises a storage bin, a material conveying machine and a urea dissolution tank. The storage bin is located below the upper end of the material conveying machine. The urea dissolving tank is positioned below the storage bin; a first sealing cover is fixedly arranged at the top of the urea dissolving tank; a sensor unit is arranged on the first sealing cover and is used for detecting the liquid level and the temperature in the urea dissolving tank; compared with the prior art, the equipment is not provided with a urea solution storage tank, the urea solution is prepared on line, the operation is simple and convenient, combustion and explosion are avoided, and compared with traditional liquid ammonia and ammonia water, the safety is high, and the cost is low. And the production cost is lower than that of ammonia water.

Description

Technical Field

[0001] The utility model belongs to the technical field of urea dissolution, in particular to a urea saturated dissolution device. Background Art

[0002] Flue gas denitrification technology is one of the safest, most reliable and mature denitrification technologies in the world and has been widely used at home and abroad. In the denitrification system, the reducing agent is the main consumable. There are currently three commonly used reducing agents: liquid ammonia, ammonia water and urea.

[0003] Liquid ammonia and ammonia water can be used directly as amino reducing agents at a low price, but their disadvantages are high volatility and irritating odor that is highly toxic to human skin and respiratory tract. They are hazardous chemicals and are subject to strict restrictions on their transportation and storage. Liquid ammonia is also a major hazard source. The state now requires that all liquid ammonia dissolving devices be replaced with other dissolving technologies. Urea has the same denitrification performance as liquid ammonia through chemical reaction products. Urea itself is a solid fertilizer, odorless and non-toxic, safe to use, and easy to transport, store and use.

[0004] However, traditional urea dissolution requires a large urea dissolution tank and a large urea liquid finished product storage tank. The dissolution needs to be carried out at a water temperature of 60-75°C, which has high energy consumption, occupies a large area, is complicated to operate, and requires special personnel to operate.

[0005] Therefore, in view of the above problems, a urea saturated dissolution device is proposed. Utility Model Content

[0006] In order to make up for the deficiencies of the prior art and solve the above-mentioned problems, a urea saturated dissolution device is proposed.

[0007] The technical solution adopted by the utility model to solve its technical problems is: a urea saturated dissolution device described in the utility model comprises a storage bin, a feeder and a urea dissolution tank; the storage bin is located below the upper end of the feeder; the urea dissolution tank is located below the storage bin; a first sealing cover is fixedly arranged on the top of the urea dissolution tank; a sensor unit is arranged on the first sealing cover, and the sensor unit is used to detect the liquid level and temperature inside the urea dissolution tank; a connected water inlet pipe is fixedly connected to the top side of one end of the urea dissolution tank; a connected discharge pipe is fixedly connected to the bottom side of the other end of the urea dissolution tank; a heater is fixedly arranged inside the urea dissolution tank.

[0008] Preferably, the sensor unit includes a liquid level sensor and a first temperature sensor fixedly connected to the top of the first sealing cover, and the liquid level sensor is located on the side of the first sealing cover close to the discharge pipe, and the first temperature sensor is located in the middle of the first sealing cover; a second temperature sensor is fixedly connected to the water inlet pipe; the liquid level sensor, the first temperature sensor and the second temperature sensor are all electrically connected to the industrial control computer.

[0009] Preferably, a first partition and a second partition are fixedly connected to the middle of the urea dissolution tank respectively; the first partition and the second partition are cross-arranged to form a zigzag passage; the position of the first partition is higher than the position of the second partition; the height of the second partition is less than the height of the water inlet pipe.

[0010] Preferably, a second sealing cover is fixedly connected to the top of the storage bin; a radar level meter is fixedly connected to the second sealing cover, and the radar level meter is used to detect the level of urea in the storage; a discharge valve is fixedly connected to the bottom of the storage bin, and the top of the discharge valve passes through the first sealing cover to the inside of the urea dissolution tank; the radar level meter is electrically connected to the industrial control machine.

[0011] Preferably, an arch breaker is fixedly provided inside the storage bin, and the arch breaker is used to prevent urea from arching.

[0012] Preferably, an auger is rotatably connected inside the feeder; a drive motor is fixedly connected to the lower end of the feeder, and the output end of the drive motor is fixedly connected to the central axis of the auger; an upper hopper connected to the interior of the feeder is fixedly connected to one end of the feeder close to the drive motor; a discharge pipe connected to the interior of the feeder is fixedly connected to one end of the feeder away from the drive motor, and the lower end of the discharge pipe is located inside the storage bin.

[0013] Beneficial effects of the utility model:

[0014] The utility model provides a urea saturated dissolution device. By adopting a PLC (DCS) control system, the automatic control of the preparation system is realized. The PLC (DCS) in the boiler control room can monitor the urea granule material level, the outlet flow rate of the circulating pump, the temperature and the pressure and other signals. The bagged urea is transported to the urea preparation area by car, and after being unpacked manually, it is put into the storage bin through a feeder, and then flows from the storage bin to the urea dissolution tank by gravity. The dissolution water is heated to 20-30°C in the water inlet pipe by electric heating or steam (waste heat), and the temperature of the dissolution water is automatically controlled. When the urea granules in the urea storage bin flow to the urea dissolution tank by gravity, the urea granules in the urea dissolution tank are heated to 20-30°C by electric heating or steam (waste heat). A certain height is formed, and process water at 20-30℃ is dissolved into a saturated urea solution through the gaps between urea particles and flows into the other end of the urea dissolution tank. A heater is provided inside the urea dissolution tank to keep the temperature of the urea dissolution tank above 30℃ to avoid urea crystallization. After the urea solution is prepared, it is sent to the pyrolysis tank through a urea solution pump and a discharge pipe, where it is decomposed into ammonia, carbon dioxide and water vapor, which are then diluted and mixed with air before entering the desulfurization and denitrification device. Compared with the prior art, the equipment does not have a urea liquid storage tank, and the urea liquid is configured online, which is easy to operate, without combustion or explosion. Compared with traditional liquid ammonia and ammonia water, it is safer, non-toxic and odorless, and has a lower production cost than ammonia water.

[0015] The utility model provides a urea saturated dissolving device. The urea dissolving process of the device is simple, the automation degree is high, the device is compact and occupies a small area, the working pressure and temperature are low, the safety is good, common equipment is adopted, the structure is simple, and the energy consumption is 50% lower than that of the traditional urea dissolving device.

[0016] The utility model provides a urea saturated dissolution device. The raw material urea particles adopted in the urea dissolution method are safe and non-toxic, easy to transport and use, relatively cheap, and superior to other ammonia production methods. The device can be applied in some cities close to residential areas, can produce ammonia on a large scale, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present application. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0018] Figure 1 It is a three-dimensional diagram of the utility model;

[0019] Figure 2 It is a cross-sectional view of the utility model;

[0020] Figure 3 yes Figure 2 A partial enlarged view of the middle A;

[0021] Figure 4 It is a three-dimensional diagram of the urea dissolving tank in the utility model;

[0022] Figure 5 It is a three-dimensional diagram of the feeder in the utility model;

[0023] Legend:

[0024] 1. Storage bin; 11. Second sealing cover; 12. Radar level meter; 2. Feeder; 21. Auger; 22. Drive motor; 23. Loading hopper; 24. Discharging pipe; 3. Urea dissolving tank; 31. First sealing cover; 32. Liquid level sensor; 33. First temperature sensor; 4. Discharging valve; 5. Water inlet pipe; 51. Second temperature sensor; 6. First partition; 61. Second partition; 7. Discharging pipe; 8. Heater. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments 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] Specific examples are given below.

[0027] Embodiment 1:

[0028] See also Figure 1-Figure 5 The utility model provides a urea saturated dissolution device, comprising a storage bin 1, a feeder 2 and a urea dissolution tank 3; the storage bin 1 is located below the upper end of the feeder 2; the urea dissolution tank 3 is located below the storage bin 1; a first sealing cover 31 is fixedly provided on the top of the urea dissolution tank 3; a sensor unit is provided on the first sealing cover 31, and the sensor unit is used to detect the liquid level and temperature inside the urea dissolution tank 3; a connected water inlet pipe 5 is fixedly connected to the top side of one end of the urea dissolution tank 3; a connected discharge pipe 7 is fixedly connected to the bottom side of the other end of the urea dissolution tank 3; a heater 8 is fixedly provided inside the urea dissolution tank 3.

[0029] During operation, in the prior art, the traditional urea dissolution requires a large urea dissolution tank 3 and a large urea liquid finished product storage tank, and the dissolution needs to be carried out at a water temperature of 60-75°C, which has high energy consumption, large floor space, complicated operation, and requires special personnel to operate. In order to solve the above problems, the utility model designs a storage bin 1, a feeder 2 and a urea dissolution tank 3. During the specific operation, a PLC (DCS) control system is adopted to realize the automatic control of the preparation system. The PLC (DCS) in the boiler control room can monitor the urea granule material level, the circulating pump outlet flow, temperature and pressure and other signals. The bagged urea is transported to the urea preparation area by car, and after manual unpacking, it is put into the storage bin 1 through the feeder 2, and then flows from the storage bin 1 to the urea dissolution tank 3 by gravity. The dissolution water uses electric heating or steam (waste heat) to heat the process water to 20-30°C in the water inlet pipe 5, and the temperature of the dissolution water is automatically controlled. When the urea granules in the urea storage bin 1 flow into the urea dissolution tank 3 by gravity, the urea The dissolving tank 3 is formed at a certain height, and the process water at 20-30°C is dissolved into a saturated urea solution through the gap between the urea particles and flows into the other end of the urea dissolving tank 3. A heater 8 is provided inside the urea dissolving tank 3 to keep the temperature of the urea dissolving tank 3 above 30°C to avoid urea crystallization. After the urea solution is prepared, it is sent to the pyrolysis tank by using a urea solution pump and a discharge pipe 7, where it is decomposed into ammonia, carbon dioxide and water vapor, and then diluted and mixed with air before entering the desulfurization and denitrification device. The principle can be summarized as follows: In summary: the process water flows through the urea granule layer from top to bottom, and the process water flows through the gaps between the urea granules and dissolves the urea at the same time. The height of the urea granule layer is utilized to make the flowing urea reach saturation. The saturated urea solution is then heated to fully dissolve the urea solution, and then it is in an unsaturated state to prevent the urea solution from crystallizing. Compared with the prior art, the equipment does not have a urea solution storage tank, and the urea solution is configured online, which is easy to operate, without combustion or explosion. Compared with traditional liquid ammonia and ammonia water, it is safer, non-toxic and tasteless, and the production cost is lower than that of ammonia water.

[0030] Further, such as Figure 2 As shown, the sensor unit includes a liquid level sensor 32 and a first temperature sensor 33 fixedly connected to the top of the first sealing cover 31, and the liquid level sensor 32 is located on the side of the first sealing cover 31 close to the discharge pipe 7, and the first temperature sensor 33 is located in the middle of the first sealing cover 31; a second temperature sensor 51 is fixedly connected to the water inlet pipe 5; the liquid level sensor 32, the first temperature sensor 33 and the second temperature sensor 51 are all electrically connected to the industrial control computer.

[0031] During operation, the liquid level height inside the urea dissolution tank 3 can be detected by the liquid level sensor 32. When the liquid level is lower than the set value, water is added, and when it is higher than the set value, water is stopped, so as to realize automatic control of the water level height inside the urea dissolution tank 3. The first temperature sensor 33 can detect the temperature inside the urea dissolution tank 3. The temperature is set to be above the saturated crystallization temperature by the heater 8 to prevent the urea solution from crystallizing. The second temperature sensor 51 cooperates with the water heating device in the water inlet pipe 5 to heat the process water to 20-30°C, so that the process water can be dissolved into a saturated urea solution through the gaps between the urea particles.

[0032] Further, such as Figure 3 As shown, the first partition 6 and the second partition 61 are fixedly connected to the middle of the urea dissolution tank 3 respectively; the first partition 6 and the second partition 61 are cross-arranged to form a zigzag passage; the position of the first partition 6 is higher than the position of the second partition 61; the height of the second partition 61 is less than the height of the water inlet pipe 5.

[0033] During operation, the partition is set so that firstly the urea particles entering the urea dissolution tank 3 can flow into the urea dissolution tank 3 by gravity, forming a certain height in the urea dissolution tank 3; secondly, the urea liquid in the two areas of the urea dissolution tank 3 can be restricted to avoid being discharged from the discharge pipe 7 due to insufficient dissolution.

[0034] Further, such as Figure 2 As shown, a second sealing cover 11 is fixedly connected to the top of the storage bin 1; a radar level meter 12 is fixedly connected to the second sealing cover 11, and the radar level meter 12 is used to detect the level of urea in the storage; a discharge valve 4 is fixedly connected to the bottom of the storage bin 1, and the top of the discharge valve 4 passes through the first sealing cover 31 to the inside of the urea dissolving tank 3; the radar level meter 12 is electrically connected to the industrial control machine.

[0035] During operation, the urea storage bin 1 is provided with a radar level gauge to display the urea material level in real time, and is provided with high and low material level prompt alarms to facilitate operators to make decisions and control the discharge valve 4.

[0036] Further, such as Figure 1 As shown, an arch breaker is fixedly arranged inside the storage bin 1, and the arch breaker is used to prevent urea from arching.

[0037] During operation, in order to prevent urea particles from being accumulated inside the storage bin 1 for a long time, resulting in the phenomenon of consolidation and arching, the arch breaker can effectively discharge urea from the discharge valve 4 to maintain patency.

[0038] Further, such as Figure 5As shown, an auger 21 is rotatably connected inside the feeder 2; a drive motor 22 is fixedly connected to the lower end of the feeder 2, and the output end of the drive motor 22 is fixedly connected to the central axis of the auger 21; an upper hopper 23 connected to the interior of the feeder 2 is fixedly connected to one end of the feeder 2 close to the drive motor 22; a discharge pipe 24 connected to the interior of the feeder 2 is fixedly connected to one end of the feeder 2 away from the drive motor 22, and the lower end of the discharge pipe 24 is located inside the storage bin 1.

[0039] During operation, the bagged urea is opened manually and poured into the upper hopper 23 , and the drive motor 22 is used to drive the auger 21 to rotate, so that the urea particles are transported to the higher discharge pipe 24 , and discharged from the discharge pipe 24 to the storage bin 1 .

[0040] Embodiment 2:

[0041] As an embodiment of the present invention: the first 40% urea solution preparation steps:

[0042] S1: Open the unloading valve 4 of the urea storage bin 1 to allow the urea granules to flow into the urea dissolving tank 3. After the urea stops flowing, open the steam and water inlet valves;

[0043] S2: Open the steam drain valve to allow steam condensate to flow into the heating return water pipe of the preparation workshop and connect it to the water inlet pipe 5. Set the water inlet temperature to 20-30℃;

[0044] S3: Open the process water inlet manual door and steam manual valve, observe the incoming water pressure and steam pressure, and when they are normal, open the process water inlet solenoid valve through the PLC (DCS) system to inject water into the urea dissolution tank 3 from the water inlet pipe 5, and the liquid level interlock is put into operation.

[0045] S4: Set the temperature and liquid level of urea dissolving tank 3. The temperature is set at 30-40℃, and the liquid level is set at 60-80%. When the liquid level is greater than 50%, heating starts. When the liquid level is lower than 70%, water starts to flow in. When the liquid level is higher than 80%, water flow stops. Then, the water inlet and steam regulating valves are opened and closed in the control system according to the set values.

[0046] Since the dissolution process of urea is an endothermic reaction, its heat of dissolution is as high as -57.8cal / g (the negative sign represents endothermic). That is to say, when 1 gram of urea is dissolved in 1 gram of water, the water temperature will drop by 30°C only when the urea is dissolved. The temperature of the saturated solution flowing out of the pyrolysis tank is -6-0°C. The urea liquid buffer tank is equipped with a heater 8, and the temperature is maintained at about 30°C to prevent the urea liquid from crystallizing.

[0047] Working principle:

[0048] The PLC (DCS) control system is adopted to realize the automatic control of the preparation system. The PLC (DCS) in the boiler control room can monitor the urea granule material level, circulation pump outlet flow, temperature and pressure and other signals. The bagged urea is transported to the urea preparation area by car, and after being unpacked manually, it is put into the storage bin 1 through the feeder 2, and then flows from the storage bin 1 to the urea dissolving tank 3 by gravity. The dissolving water is heated to 20-30℃ in the water inlet pipe 5 by electric heating or steam (waste heat), and the dissolving water temperature is automatically controlled. When the urea granules in the urea storage bin 1 flow to the urea dissolving tank 3 by gravity, a certain height is formed in the urea dissolving tank 3. , the process water at 20-30°C is dissolved into a saturated urea solution through the gaps between the urea particles, and flows into the other end of the urea dissolving tank 3. A heater 8 is provided inside the urea dissolving tank 3 to keep the temperature of the urea dissolving tank 3 above 30°C to prevent urea crystallization; after the urea solution is prepared, it is sent to the pyrolysis tank by using a urea solution pump and a discharge pipe 7, where it is decomposed into ammonia, carbon dioxide and water vapor, and then diluted and mixed with air before entering the desulfurization and denitrification device. Compared with the prior art, the equipment does not have a urea liquid storage tank, the urea liquid is configured online, the operation is simple, there is no combustion, and there is no explosion. Compared with traditional liquid ammonia and ammonia water, it is safer, non-toxic and tasteless, and the production cost is lower than that of ammonia water;

[0049] The liquid level height inside the urea dissolving tank 3 can be detected by the liquid level sensor 32. When the liquid level is lower than the set value, water is added, and when it is higher than the set value, water is stopped, so as to realize automatic control of the water level height inside the urea dissolving tank 3. The first temperature sensor 33 can detect the temperature inside the urea dissolving tank 3. The temperature is set to be above the saturated crystallization temperature by the heater 8 to prevent the urea solution from crystallizing. The second temperature sensor 51 cooperates with the water heating device in the water inlet pipe 5 to heat the process water to 20-30°C, so that the process water can be dissolved into a saturated urea solution through the gaps between the urea particles.

[0050] The above shows and describes the basic principle, main features and advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model may have various changes and improvements, and these changes and improvements fall within the scope of the utility model to be protected.

Claims

1. A urea saturated dissolution device, characterized in that: The invention comprises a storage bin (1), a feeder (2) and a urea dissolving tank (3); the storage bin (1) is located below the upper end of the feeder (2); the urea dissolving tank (3) is located below the storage bin (1); a first sealing cover (31) is fixedly arranged on the top of the urea dissolving tank (3); a sensor unit is arranged on the first sealing cover (31), and the sensor unit is used to detect the liquid level and temperature inside the urea dissolving tank (3); a connected water inlet pipe (5) is fixedly connected to the top side of one end of the urea dissolving tank (3); a connected discharge pipe (7) is fixedly connected to the bottom side of the other end of the urea dissolving tank (3); and a heater (8) is fixedly arranged inside the urea dissolving tank (3).

2. A urea saturated dissolution device according to claim 1, characterized in that: The sensor unit comprises a liquid level sensor (32) and a first temperature sensor (33) fixedly connected to the top of the first sealing cover (31), wherein the liquid level sensor (32) is located on a side of the first sealing cover (31) close to the discharge pipe (7), and the first temperature sensor (33) is located in the middle of the first sealing cover (31); a second temperature sensor (51) is fixedly connected to the water inlet pipe (5); and the liquid level sensor (32), the first temperature sensor (33) and the second temperature sensor (51) are all electrically connected to the industrial control computer.

3. A urea saturated dissolution device according to claim 2, characterized in that: A first partition (6) and a second partition (61) are fixedly connected to the middle of the urea dissolution tank (3); the first partition (6) and the second partition (61) are arranged crosswise to form a meandering passage; the position of the first partition (6) is higher than that of the second partition (61); and the height of the second partition (61) is less than the height of the water inlet pipe (5).

4. A urea saturated dissolution device according to claim 3, characterized in that: The top of the storage bin (1) is fixedly connected to a second sealing cover (11); the second sealing cover (11) is fixedly connected to a radar level meter (12), and the radar level meter (12) is used to detect the level of urea in the storage; the bottom of the storage bin (1) is fixedly connected to a discharge valve (4), and the top of the discharge valve (4) passes through the first sealing cover (31) to the inside of the urea dissolving tank (3); the radar level meter (12) is electrically connected to an industrial control computer.

5. A urea saturated dissolution device according to claim 4, characterized in that: An arch breaker is fixedly arranged inside the storage bin (1), and the arch breaker is used to prevent urea from arching.

6. A urea saturated dissolution device according to claim 5, characterized in that: An auger (21) is rotatably connected inside the feeder (2); a drive motor (22) is fixedly connected to the lower end of the feeder (2), and the output end of the drive motor (22) is fixedly connected to the central axis of the auger (21); an upper hopper (23) connected to the interior of the feeder (2) is fixedly connected to one end of the feeder (2) close to the drive motor (22); a lower feed pipe (24) connected to the interior of the feeder (2) is fixedly connected to one end of the feeder (2) away from the drive motor (22), and the lower end of the lower feed pipe (24) is located inside the storage bin (1).

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