Biomass boiler denitration urea solution automatic preparation system

Abstract

The application discloses a kind of automatic preparation system of biomass boiler denitration with urea solution, including stirring cylinder and control device, stirring cylinder includes the inner cylinder and outer cylinder of coaxial distribution, preliminary mixing cavity is enclosed in inner cylinder, and fine mixing cavity is enclosed between inner cylinder and outer cylinder;Water supply device and urea input device are equipped at the top of stirring cylinder, and drainage device is equipped at the bottom of stirring cylinder;The side wall of inner cylinder is provided with a plurality of flow guide holes that are connected with preliminary mixing cavity and fine mixing cavity;Rotary shaft is rotatably installed in the inner cavity of preliminary mixing cavity and coaxially distributed with inner cylinder, driving impeller is fixedly arranged on the upper portion of rotary shaft, at least one stirring paddle is fixedly arranged on the lower portion of rotary shaft, water injection pipe is arranged on the upper portion of the inner wall of inner cylinder, water injection pipe is provided with a plurality of spray heads for spraying water towards driving impeller, backflow port is arranged on the lower portion of outer cylinder, and backflow device is connected between backflow port and water injection pipe.The application uses multistage mixing and utilizes backflow water to promote stirring, which significantly improves the preparation efficiency and quality of urea solution.

Description

Technical Field

[0001] This invention relates to the field of denitrification technology for biomass boilers, and in particular to an automatic urea solution preparation system for denitrification of biomass boilers. Background Technology

[0002] Biomass boilers generate large amounts of nitrogen oxides during operation, causing environmental pollution. Urea solution (a urea aqueous solution with a mass concentration of 30%~50%) is a commonly used denitrification agent, but existing urea solution preparation devices have the following problems: (1) Uneven mixing: Traditional equipment cannot guarantee that urea and water are fully mixed, resulting in uneven solution concentration and unstable denitrification efficiency; (2) Crystallization problem: Urea solution is prone to crystallization at low temperatures, which affects equipment operation; (3) The slow dissolution rate of urea affects the timely supply of denitrification agent; (4) An electric stirring device is required to complete the stirring and dissolution of urea, which consumes a lot of electricity. Summary of the Invention

[0003] The purpose of this invention is to provide an automatic urea solution preparation system for denitrification of biomass boilers. By adopting multi-stage mixing and using reflux water to drive stirring, the system significantly improves the preparation efficiency and quality of urea solution and effectively solves the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides an automatic urea solution preparation system for denitrification in biomass boilers, comprising a stirring drum and a control device. The stirring drum includes an inner drum and an outer drum coaxially distributed. The inner drum forms a preliminary mixing chamber, and the inner drum and the outer drum form a fine mixing chamber. The top of the stirring drum is provided with a water supply device and a urea input device respectively connected to the preliminary mixing chamber, and the bottom of the stirring drum is provided with a drain device connected to the fine mixing chamber. The side wall of the inner drum has several guide holes connecting the preliminary mixing chamber and the fine mixing chamber. A rotating shaft coaxially distributed with the inner drum is rotatably mounted in the inner cavity of the preliminary mixing chamber. A drive impeller is fixedly mounted on the upper part of the rotating shaft, and at least one stirring paddle is fixedly mounted on the lower part of the rotating shaft. A water spray pipe is provided on the upper part of the inner wall of the inner drum, and the water spray pipe has several nozzles spraying water toward the drive impeller. The lower part of the outer drum has a return port connected to the fine mixing chamber, and a return device is connected between the return port and the water spray pipe.

[0005] Furthermore, the water supply device includes a water inlet located at the top of the mixing drum, a water storage tank for storing water, and a water delivery pipe. The two ends of the water delivery pipe are respectively connected to the water inlet and the bottom of the water storage tank. The water delivery pipe is equipped with a water pump, a flow meter, and a water inlet valve.

[0006] Furthermore, the urea input device includes a urea input port located at the top of the mixing drum, a urea storage tank for storing urea granules, and a screw conveyor with weighing function. The bottom of the urea storage tank is connected to the feed end of the screw conveyor, and the discharge end of the screw conveyor is connected to the urea input port.

[0007] Furthermore, the bottom of the urea storage tank has a cone-shaped hopper, and the side wall of the hopper is provided with a preheating device for preheating the urea.

[0008] Furthermore, the draining device includes a discharge port located at the bottom of the outer cylinder and a drain pipe connected to the discharge port, wherein the drain pipe is equipped with a discharge valve and a discharge pump.

[0009] Furthermore, the reflux device includes a reflux pipe and a reflux pump and a reflux valve installed on the reflux pipe, and an auxiliary heating device is installed on the pipe wall of the reflux pipe.

[0010] Furthermore, a magnetic drive turntable is fixed at the bottom of the rotating shaft, and a magnetic stirring device is provided at the bottom of the fine mixing chamber below the magnetic drive turntable. The magnetic drive turntable is connected to the magnetic stirring device by magnetic attraction and drives the magnetic stirring device to rotate.

[0011] Furthermore, the magnetic stirring device includes a magnetic driven turntable rotatably mounted on the bottom wall of the inner cylinder via a fixed shaft and several stirring blades fixed on the side wall of the magnetic driven turntable. The fixed shaft and the rotating shaft are coaxially distributed. The magnetic driven turntable is provided with a first magnet block, and the magnetic driven turntable is provided with a second magnet block that magnetically attracts and cooperates with the first magnet block.

[0012] Furthermore, the inner wall of the outer cylinder is provided with an ultrasonic transducer plate connected to the ultrasonic generator, and the outer wall of the inner cylinder is provided with a reflector plate.

[0013] Furthermore, the outer wall of the outer cylinder is provided with a heat insulation layer, and the inner wall of the inner cylinder is provided with a main heating device. The main heating device is an electric heating tube fixed on the inner wall of the inner cylinder. The control device includes a PLC controller and a temperature sensor. The temperature sensor and the electric heating tube are electrically connected to the PLC controller.

[0014] Compared with the prior art, the present invention provides an automatic urea solution preparation system for denitrification of biomass boilers, which has the following beneficial effects: The preliminary mixing chamber and the fine mixing chamber of this invention are used for the preliminary dissolution of urea particles and the fine dispersion of the solution, respectively, to ensure the uniformity of the solution. By activating the reflux device and using the reflux water to drive the stirring, there is no need to configure additional electric stirring equipment. This can achieve both circulation to promote dissolution and use the kinetic energy of the sprayed water column as a power source to drive the impeller to rotate, thus achieving low energy consumption and high efficiency in stirring and mixing. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of a circulating stirring system. Figure 3 A schematic diagram showing how a recirculating water jet drives the impeller to rotate; Figure 4 This is a schematic diagram of a magnetic stirring device that uses a magnetically driven turntable to rotate. Figure 5 This is a block diagram illustrating the control principle of the present invention.

[0017] Reference numerals: 1. Stirring cylinder; 11. Inner cylinder; 111. Guide hole; 112. Reflector plate; 113. Main heating device; 12. Outer cylinder; 121. Return port; 122. Insulation layer; 13. Preliminary mixing chamber; 14. Fine mixing chamber; 15. Rotating shaft; 151. Drive impeller; 1511. Drive wheel body; 1512. Agitator blade; 152. Stirring paddle; 16. Water spray pipe; 161. Nozzle; 17. Magnetic drive turntable; 171. First magnet block; 18. Magnetic stirring device; 181. Fixed shaft; 182. Magnetic driven turntable; 183. Stirring blade; 184. Second magnet block; 19. Ultrasonic vibration. 1. Plate; 191. Ultrasonic generator; 2. Water supply device; 21. Water inlet; 22. Water storage tank; 23. Water delivery pipe; 24. Water pump; 25. Flow meter; 26. Water inlet valve; 3. Urea input device; 31. Urea inlet; 32. Urea storage tank; 321. Discharge hopper; 33. Screw conveyor; 34. Preheating device; 4. Drainage device; 41. Discharge port; 42. Drainage pipe; 43. Discharge valve; 44. Discharge pump; 5. Reflux device; 51. Reflux pipe; 52. Reflux pump; 53. Reflux valve; 54. Auxiliary heating device; 6. Control device; 61. PLC controller; 62. Temperature sensor. Detailed Implementation

[0018] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] The present invention will now be described in further detail through detailed embodiments and in conjunction with the accompanying drawings.

[0020] refer to Figures 1-5 This embodiment provides an automatic urea solution preparation system for denitrification in biomass boilers, including a stirring drum 1 and a control device 6. The stirring drum 1 includes an inner drum 11 and an outer drum 12 coaxially distributed. The inner drum 11 forms a preliminary mixing chamber 13, and a fine mixing chamber 14 is formed between the inner drum 11 and the outer drum 12. The top of the stirring drum 1 is provided with a water supply device 2 and a urea input device 3 respectively communicating with the preliminary mixing chamber 13, and the bottom of the stirring drum 1 is provided with a draining device 4 communicating with the fine mixing chamber 14. The side wall of the inner drum 11 has several openings communicating with the preliminary mixing chamber 13. The fine mixing chamber 14 has a guide hole 111; the inner cavity of the preliminary mixing chamber 13 is rotatably mounted with a rotating shaft 15 coaxially distributed with the inner cylinder 11, the upper part of the rotating shaft 15 is fixedly provided with a drive impeller 151, the lower part of the rotating shaft 15 is fixedly provided with at least one stirring paddle 152, the upper part of the inner wall of the inner cylinder 11 is provided with a water spray pipe 16, the water spray pipe 16 is provided with a plurality of nozzles 161 spraying water toward the drive impeller 151, the lower part of the outer cylinder 12 is provided with a return port 121 communicating with the fine mixing chamber 14, and a return device 5 is connected between the return port 121 and the water spray pipe 16. The preliminary mixing chamber and the fine mixing chamber are used for the preliminary dissolution of urea particles and the fine dispersion of the solution, respectively, to ensure the uniformity of the solution. By activating the reflux device, the reflux water is used to drive the stirring, eliminating the need for additional electric stirring equipment. This achieves both circulation to promote dissolution and the use of the kinetic energy of the sprayed water column as a power source to drive the impeller to rotate, thus achieving low-energy consumption and high-efficiency stirring and mixing.

[0021] In this embodiment, the outer wall of the outer cylinder 12 is provided with a heat insulation layer 122, and the inner wall of the inner cylinder 11 is provided with a main heating device 113. The main heating device 113 is an electric heating tube fixed on the inner wall of the inner cylinder 11. The control device 6 includes a PLC controller 61 and a temperature sensor 62. The temperature sensor 62 and the electric heating tube are electrically connected to the PLC controller 61. By setting up the main heating device, the solution can be heated to maintain the dissolution temperature and avoid crystallization. At the same time, by setting up the heat insulation layer, heat loss can be further avoided, especially in low-temperature environments such as winter when preparing urea solution, the solution temperature can be well maintained.

[0022] In some specific implementation methods, such as Figure 3 As shown, the drive impeller 151 includes a disc-shaped drive wheel body 1511 and several bucket-shaped agitator blades 1512 fixed to the side wall of the drive wheel body 1511. Due to the arrangement of multiple specially shaped agitator blades, the backflowing water jet can stably drive the drive impeller to rotate.

[0023] In some specific implementation methods, such as Figure 2 and Figure 4 As shown, the guide holes 111 are spaced apart vertically and arranged in a circumferential array along the central axis of the inner cylinder 11. This facilitates the rapid flow of the solution in the preliminary mixing chamber to the fine mixing chamber located on the outer periphery under the action of stirring and centrifugation, thereby promoting the dissolution and uniform mixing of urea.

[0024] In some specific implementation methods, refer to Figure 1 and Figure 5 The water supply device 2 includes a water inlet 21 located at the top of the mixing drum 1, a water storage tank 22 for storing water, and a water delivery pipe 23. The two ends of the water delivery pipe 23 are connected to the water inlet 21 and the bottom of the water storage tank 22, respectively. The water delivery pipe 23 is equipped with a water pump 24, a flow meter 25, and a water inlet valve 26. In this way, water for dissolving urea can be pumped quantitatively into the mixing drum.

[0025] In some specific implementation methods, refer to Figure 1 and Figure 5 The urea input device 3 includes a urea inlet 31 located at the top of the mixing drum 1, a urea storage tank 32 for storing urea granules, and a screw conveyor 33 with weighing function. The bottom of the urea storage tank 32 is connected to the feed end of the screw conveyor 33, and the discharge end of the screw conveyor 33 is connected to the urea inlet 31. In this way, a metered amount of urea to be dissolved can be added into the mixing drum. As an example, the screw conveyor is a metering conveyor from the brand Huazhu, which is a weighing screw conveyor with a carbon steel auger structure.

[0026] As an improved implementation method, refer to Figure 1 and Figure 5 The urea storage tank 32 has a conical discharge hopper 321 at its bottom, and a preheating device 34 for preheating the urea is provided on the side wall of the discharge hopper 321. The discharge hopper facilitates rapid discharge of urea; simultaneously, by providing a preheating device at the discharge hopper of the urea storage tank, the urea particles can be preheated, lowering the crystallization point of the urea and improving dissolution efficiency. Specifically, the preheating device 34 is an electric heating jacket.

[0027] In some specific implementation methods, refer to Figure 1 and Figure 5 The draining device 4 includes a discharge port 41 located at the bottom of the outer cylinder 12 and a drain pipe 42 connected to the discharge port 41. The drain pipe 42 is equipped with a discharge valve 43 and a discharge pump 44. Thus, after the urea solution preparation is completed, it can be quickly discharged by opening the discharge valve and starting the discharge pump.

[0028] In some specific implementation methods, refer to Figure 1 , Figure 2 and Figure 5 The reflux device 5 includes a reflux pipe 51, a reflux pump 52, and a reflux valve 53 installed on the reflux pipe 51. An auxiliary heating device 54 is installed on the wall of the reflux pipe 51. By starting the reflux pump and opening the reflux valve, the suction action of the reflux pump can achieve solution circulation, thereby accelerating urea dissolution and promoting uniform dispersion. Furthermore, the auxiliary heating device reduces heat loss, maintains the solution temperature, and effectively prevents crystallization. Specifically, the auxiliary heating device 54 is an electric heating tape wound along the reflux pipe.

[0029] As an improved implementation method, refer to Figure 1 , Figure 2 , Figure 4 and Figure 5 A magnetically driven turntable 17 is fixed to the bottom of the rotating shaft 15. A magnetic stirring device 18 is located below the magnetically driven turntable 17 in the lower part of the fine mixing chamber 14. The magnetically driven turntable 17 is connected to the magnetic stirring device 18 by magnetic attraction and drives the magnetic stirring device 18 to rotate. Because of the magnetic drive method, the stirring paddle in the preliminary mixing chamber and the magnetic stirring device in the fine mixing chamber can be linked together, achieving synchronous rotation to stir the solution under the impact of the reflux water column. This provides both good stirring and mixing effect and simplifies the stirring structure. Specifically, the lower part of the fine mixing chamber 14 has a cone-shaped discharge stirring space, and the magnetic stirring device 18 is installed in the discharge stirring space.

[0030] In some specific implementation methods, such as Figure 4 As shown, the magnetic stirring device 18 includes a magnetically driven turntable 182 rotatably mounted on the bottom wall of the inner cylinder 11 via a fixed shaft 181, and several stirring blades 183 fixed on the side wall of the magnetically driven turntable 182. The fixed shaft 181 and the rotating shaft 15 are coaxially distributed. The magnetically driven turntable 17 is provided with a first magnet block 171, and the magnetically driven turntable 182 is provided with a second magnet block 184 that magnetically engages with the first magnet block 171. As an example, four first magnet blocks 171 can be symmetrically installed on the magnetically driven turntable 17, and the polarities of the four first magnet blocks 171 near the magnetically driven turntable 182 are sequentially NNSNS; four second magnet blocks 184 are correspondingly installed on the magnetically driven turntable 182, and the polarities of the four second magnet blocks 184 near the magnetically driven turntable 17 are sequentially SNSN. In this way, a good magnetic attraction and linkage between the magnetically driven turntable and the magnetically driven turntable can be ensured, and demagnetization is not easy.

[0031] As an improved implementation method, refer to Figure 1 , Figure 2 and Figure 5 The inner wall of the outer cylinder 12 is provided with an ultrasonic transducer 19 connected to an ultrasonic generator 191, and the outer wall of the inner cylinder 11 is provided with a reflector 112. The high-frequency ultrasonic waves generated by the transducer propagate in the solution, producing cavitation and microfluidic effects, removing bubbles, promoting urea dissolution, and improving mixing uniformity. Furthermore, the reflector enhances the ultrasonic mixing effect through reflection. As an example, the ultrasonic transducer is model XTA-1036S.

[0032] refer to Figures 1-5 The working process of this invention is as follows: In use, the required amount of water is first pumped into the mixing tank 1 by the water inlet pump 24, and the reflux pump 52 is continuously turned on to circulate the liquid and drive the stirring paddle 152 and the magnetic stirring device 18 to rotate. The auxiliary heating device 54 is activated to maintain the temperature and the ultrasonic generator 191 is started. Next, the urea to be dissolved is added quantitatively into the mixing tank 1 and the main heating device 113 is activated to prevent crystallization, and ultrasonic circulation stirring is performed. The urea is initially stirred and mixed with water in the preliminary mixing chamber 13 and then flows into the outer fine mixing chamber 14 for further mixing under the stirring and centrifugal action of the stirring paddle 152. After ultrasonic cavitation, the dissolution and uniform dispersion of urea are promoted. At the same time, the magnetic stirring device 18 located at the bottom of the fine mixing chamber 14 will also further stir and mix the solution to improve the urea dissolution effect.

[0033] During the ultrasonic circulation stirring process, the liquid located in the lower part of the fine mixing chamber 14 flows back to the upper part of the primary mixing chamber 13 through the return pipe 51, and the liquid is supplemented with appropriate heat by the auxiliary heating device 54 during the flow through the return pipe 51. After the return liquid re-enters the primary mixing chamber 13, the sprayed water column can form a continuous water flow thrust to drive the impeller 151 to rotate, thereby realizing the automatic stirring of the stirring paddle 152 and the magnetic stirring device 18.

[0034] After a preset time, the preparation of the urea solution is completed. The ultrasonic, heating and reflux pumps are turned off, and the prepared urea solution is discharged through the drain pipe 42.

[0035] It should be noted that the ultrasonic vibrating plate, ultrasonic generator, water inlet pump, flow meter, water inlet valve, screw conveyor, discharge valve, discharge pump, return pump, return valve, PLC controller, temperature sensor, electric heating tube, electric heating jacket, electric heating tape, and other components used in this invention are all existing electrical structures. Those skilled in the art can use and install these electrical structures according to the concept of this invention. Therefore, the specific structural details of these structures will not be described in detail in this invention.

[0036] The above embodiments are merely illustrative of the concept and technical solution of the present invention and are not intended to limit the present invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

[0037] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An automatic urea solution preparation system for denitrification in biomass boilers, comprising a stirring tank and a control device, characterized in that, The mixing drum includes an inner drum and an outer drum coaxially distributed. The inner drum forms a preliminary mixing chamber, and the inner drum and the outer drum form a fine mixing chamber. The top of the mixing drum is provided with a water supply device and a urea input device respectively connected to the preliminary mixing chamber, and the bottom of the mixing drum is provided with a drain device connected to the fine mixing chamber. The side wall of the inner drum has several guide holes connecting the preliminary mixing chamber and the fine mixing chamber. A rotating shaft coaxially distributed with the inner drum is rotatably mounted in the inner cavity of the preliminary mixing chamber. A drive impeller is fixedly mounted on the upper part of the rotating shaft, and at least one stirring paddle is fixedly mounted on the lower part of the rotating shaft. A water spray pipe is provided on the upper part of the inner wall of the inner drum. The water spray pipe has several nozzles that spray water toward the drive impeller. The lower part of the outer drum has a return port connected to the fine mixing chamber. A return device is connected between the return port and the water spray pipe. The return device includes a return pipe and a return pump and a return valve installed on the return pipe. An auxiliary heating device is installed on the wall of the return pipe.

2. The automatic urea solution preparation system for denitrification of biomass boilers according to claim 1, characterized in that, The water supply device includes a water inlet located at the top of the mixing drum, a water storage tank for storing water, and a water delivery pipe. The two ends of the water delivery pipe are respectively connected to the water inlet and the bottom of the water storage tank. The water delivery pipe is equipped with a water pump, a flow meter, and a water inlet valve.

3. The automatic urea solution preparation system for denitrification of biomass boilers according to claim 1, characterized in that, The urea input device includes a urea inlet located at the top of the mixing drum, a urea storage tank for storing urea granules, and a screw conveyor with weighing function. The bottom of the urea storage tank is connected to the feed end of the screw conveyor, and the discharge end of the screw conveyor is connected to the urea inlet.

4. The automatic urea solution preparation system for denitrification of biomass boilers according to claim 3, characterized in that, The bottom of the urea storage tank has a cone-shaped hopper, and the side wall of the hopper is provided with a preheating device for preheating the urea.

5. The automatic urea solution preparation system for denitrification of biomass boilers according to claim 1, characterized in that, The draining device includes a discharge port located at the bottom of the outer cylinder and a drain pipe connected to the discharge port. The drain pipe is equipped with a discharge valve and a discharge pump.

6. The automatic urea solution preparation system for denitrification of biomass boilers according to claim 1, characterized in that, A magnetic drive turntable is fixed at the bottom of the rotating shaft, and a magnetic stirring device is provided at the bottom of the fine mixing chamber below the magnetic drive turntable. The magnetic drive turntable is connected to the magnetic stirring device by magnetic attraction and drives the magnetic stirring device to rotate.

7. The automatic urea solution preparation system for denitrification of biomass boilers according to claim 6, characterized in that, The magnetic stirring device includes a magnetic driven turntable rotatably mounted on the bottom wall of the inner cylinder via a fixed shaft and several stirring blades fixed on the side wall of the magnetic driven turntable. The fixed shaft and the rotating shaft are coaxially distributed. The magnetic driven turntable is provided with a first magnet block, and the magnetic driven turntable is provided with a second magnet block that magnetically attracts and cooperates with the first magnet block.

8. The automatic urea solution preparation system for denitrification of biomass boilers according to claim 1, characterized in that, The inner wall of the outer cylinder is provided with an ultrasonic transducer plate connected to an ultrasonic generator, and the outer wall of the inner cylinder is provided with a reflector plate.

9. The automatic urea solution preparation system for denitrification of biomass boilers according to any one of claims 1 to 8, characterized in that, The outer wall of the outer cylinder is provided with a heat insulation layer, and the inner wall of the inner cylinder is provided with a main heating device. The main heating device is an electric heating tube fixed on the inner wall of the inner cylinder. The control device includes a PLC controller and a temperature sensor. The temperature sensor and the electric heating tube are electrically connected to the PLC controller.

Images