Automatic preparation system of urea solution for denitration of biomass boiler

Abstract

The invention discloses a biomass boiler denitration urea solution automatic preparation system, which comprises a stirring cylinder and a control device, the stirring cylinder comprises an inner cylinder and an outer cylinder which are coaxially distributed, the inner cylinder defines a preliminary mixing cavity, and a fine mixing cavity is defined between the inner cylinder and the outer cylinder; a water supply device and a urea input device are arranged at the top of the stirring barrel; a liquid discharge device is arranged at the bottom of the stirring barrel; a plurality of flow guide holes communicated with the primary mixing cavity and the fine mixing cavity are formed in the side wall of the inner cylinder; a driving impeller is fixedly arranged on the upper portion of the rotating shaft, at least one stirring paddle is fixedly arranged on the lower portion of the rotating shaft, a water spraying pipe is arranged on the upper portion of the inner wall of the inner cylinder, and the water spraying pipe is provided with a plurality of spraying heads spraying water towards the driving impeller; a backflow device is connected between the backflow opening and the water spraying pipe. By adopting a multi-stage mixing mode and utilizing reflux water to push and stir, the preparation efficiency and quality of the urea solution are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of biomass boiler denitrification, and in particular to an automatic preparation system of urea solution for biomass boiler denitrification. Background Art

[0002] Biomass boilers produce large amounts of nitrogen oxides during operation, polluting the environment. Urea solution (a urea solution with a mass concentration of 30% to 50%) is a commonly used denitrification agent, but the existing urea solution preparation devices have the following problems: (1) Uneven mixing: Traditional devices cannot ensure sufficient mixing of urea and water, resulting in uneven solution concentration and unstable denitrification efficiency; (2) Crystallization problem: Urea solution is prone to crystallization in low temperature environment, affecting equipment operation; (3) Urea dissolves slowly, affecting the timely supply of denitrification agents; (4) Electric stirring equipment is required to complete the stirring and dissolution of urea, which consumes a lot of electricity. Summary of the Invention

[0003] The purpose of the present invention is to provide an automatic preparation system for urea solution for denitrification of biomass boilers, which adopts multi-stage mixing and utilizes reflux water to promote stirring, thereby significantly improving the preparation efficiency and quality of urea solution and well solving the problems mentioned in the above background technology.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention provides an automatic preparation system for urea solution for denitrification of a biomass boiler, comprising a mixing drum and a control device, wherein the mixing drum comprises an inner drum and an outer drum distributed coaxially, the inner drum forming a preliminary mixing chamber, and a fine mixing chamber formed between the inner drum and the outer drum; a water supply device and a urea input device respectively connected to the preliminary mixing chamber are provided on the top of the mixing drum, and a liquid discharge device connected to the fine mixing chamber is provided at the bottom of the mixing drum; a plurality of guide holes connecting the preliminary mixing chamber and the fine mixing chamber are opened on the side wall of the inner drum; a rotating shaft coaxially distributed with the inner drum is rotatably mounted in the inner cavity of the preliminary mixing chamber, a driving impeller is fixedly provided on the upper part of the rotating shaft, and at least one stirring paddle is fixedly provided 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 is provided with a plurality of nozzles for spraying water toward the driving impeller; a reflux port connected to the fine mixing chamber is provided at the lower part of the outer drum, and a reflux device is connected between the reflux port and the water spray pipe.

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

[0006] Furthermore, the urea input device includes a urea input port arranged on the top of the mixing drum, a urea storage tank for storing urea granules, and a screw conveyor with a 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 is provided with a conical lower hopper, and the side wall of the lower hopper is provided with a preheating device for preheating urea.

[0008] Furthermore, the liquid discharge device includes a discharge port arranged at the bottom of the outer cylinder and a liquid discharge pipe connected to the discharge port, and the liquid discharge pipe is installed 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 magnetically driven turntable is fixed to the bottom of the rotating shaft, and a magnetic stirring device is provided at the lower part of the fine mixing chamber below the magnetically driven turntable. The magnetically driven turntable is connected to the magnetic stirring device through 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 through a fixed shaft and a plurality of stirring blades fixed on the side walls of the magnetic driven turntable. The fixed shaft and the rotating shaft are coaxially distributed. The magnetic drive turntable is provided with a first magnet block, and the magnetic driven turntable is provided with a second magnet block that is magnetically attracted to and cooperates with the first magnet block.

[0012] Furthermore, an ultrasonic vibration plate connected to an ultrasonic generator is provided on the inner wall of the outer tube, and a reflecting plate is provided on the outer wall of the inner tube.

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

[0014] Compared with the prior art, the present invention provides an automatic preparation system for urea solution for denitrification of biomass boilers, which has the following beneficial effects: The preliminary mixing chamber and the fine mixing chamber of the present invention are respectively used for the preliminary dissolution of urea granules and the fine dispersion of the solution, thereby ensuring the uniformity of the solution. By starting the reflux device and utilizing the reflux water to promote stirring, no additional electric stirring equipment is required. This not only enables circulating flow to promote dissolution, but also utilizes the kinetic energy of the ejected water column as a power source to drive the impeller to rotate, thereby achieving low energy consumption and efficient stirring and mixing. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 It is a schematic diagram of circulating stirring; Figure 3 This is a schematic diagram of using backflow water spray to drive the impeller to rotate; Figure 4 A schematic diagram of utilizing a magnetic drive turntable to drive the magnetic stirring device to rotate; Figure 5 This is a block diagram of the control principle of the present invention.

[0017] Figure 1: 1. Mixing drum; 11. Inner drum; 111. Guide hole; 112. Reflecting plate; 113. Main heating device; 12. Outer drum; 121. Return port; 122. Insulation layer; 13. Preliminary mixing chamber; 14. Fine mixing chamber; 15. Rotating shaft; 151. Driving impeller; 1511. Driving wheel body; 1512. Stirring blade; 152. Stirring paddle; 16. Spray pipe; 161. Spray head; 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 Plate; 191. Ultrasonic generator; 2. Water supply device; 21. Water inlet; 22. Water storage tank; 23. Water pipe; 24. Water inlet pump; 25. Flow meter; 26. Water inlet valve; 3. Urea input device; 31. Urea input port; 32. Urea storage tank; 321. Lower hopper; 33. Screw conveyor; 34. Preheating device; 4. Drainage device; 41. Discharge port; 42. Drain 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 DESCRIPTION

[0018] The technical solutions of the present invention are described clearly and completely below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are also within the scope of protection of the present invention.

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

[0020] refer to Figures 1 to 5 The present embodiment provides an automatic preparation system for urea solution for denitrification of a biomass boiler, comprising a mixing drum 1 and a control device 6. The mixing drum 1 comprises an inner drum 11 and an outer drum 12 coaxially distributed, wherein 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; a water supply device 2 and a urea input device 3 respectively connected to the preliminary mixing chamber 13 are provided on the top of the mixing drum 1, and a liquid discharge device 4 connected to the fine mixing chamber 14 is provided at the bottom of the mixing drum 1; a plurality of channels connected to the preliminary mixing chamber 13 are opened on the side wall of the inner drum 11. and the guide hole 111 of the fine mixing chamber 14; the inner cavity of the preliminary mixing chamber 13 is rotatably installed with a rotating shaft 15 coaxially distributed with the inner cylinder 11, and a driving impeller 151 is fixedly provided on the upper part of the rotating shaft 15, and at least one stirring paddle 152 is fixedly provided on the lower part of the rotating shaft 15. A water spray pipe 16 is provided on the upper part of the inner wall of the inner cylinder 11, and the water spray pipe 16 is provided with a plurality of nozzles 161 that spray water toward the driving impeller 151. The lower part of the outer cylinder 12 is provided with a reflux port 121 connected to the fine mixing chamber 14, and a reflux device 5 is connected between the reflux port 121 and the water spray pipe 16. Among them, the preliminary mixing chamber and the fine mixing chamber are used for the preliminary dissolution of urea granules and the fine dispersion of the solution respectively to ensure the uniformity of the solution; by starting the reflux device and using the reflux water to promote stirring, there is no need for additional electric stirring equipment. It can not only achieve circulating flow to promote dissolution, but also use the kinetic energy of the ejected water column as the power source to drive the impeller to rotate, achieving low energy consumption and efficient stirring and mixing.

[0021] In this embodiment, the outer wall of the outer cylinder 12 is provided with an 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 to the inner wall of the inner cylinder 11. The control device 6 includes a PLC controller 61 and a temperature sensor 62, each of which is electrically connected to the PLC controller 61. The main heating device can heat the solution to maintain the dissolution temperature and prevent crystallization. At the same time, the insulation layer can further prevent heat loss, which is particularly effective in maintaining the solution temperature when preparing urea solution in low-temperature environments such as winter.

[0022] In some specific embodiments, such as Figure 3 As shown, the driving impeller 151 includes a disc-shaped driving wheel body 1511 and a plurality of bucket-shaped paddles 1512 fixed to the sidewalls of the driving wheel body 1511. Due to the provision of multiple specially shaped paddles, the water column ejected by the reflux can more stably drive the driving impeller to rotate.

[0023] In some specific embodiments, such as Figure 2 and Figure 4 As shown, the guide holes 111 are spaced apart in the vertical direction and arranged in a circular array along the central axis of the inner cylinder 11. This allows the solution in the preliminary mixing chamber to flow quickly to the fine mixing chamber located on the periphery under the stirring and centrifugal action, thereby promoting the dissolution and uniform mixing of urea.

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

[0025] In some specific embodiments, reference 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 a 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. This allows for the quantitative addition of urea to be dissolved into the mixing drum. For example, the screw conveyor is a Huazhu metering conveyor with a weighing screw conveyor 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 lower hopper 321 at its bottom. A preheating device 34 for preheating the urea is installed on the sidewall of the lower hopper 321. This lower hopper facilitates rapid urea discharge. Furthermore, the preheating device in the lower hopper of the urea storage tank preheats the urea granules, lowering the crystallization point and improving dissolution efficiency. Specifically, the preheating device 34 is an electric heating jacket.

[0027] In some specific embodiments, reference Figure 1 and Figure 5 The discharge device 4 includes a discharge port 41 provided at the bottom of the outer cylinder 12 and a discharge pipe 42 connected to the discharge port 41. The discharge pipe 42 is equipped with a discharge valve 43 and a discharge pump 44. When the urea solution is prepared, it can be quickly discharged by opening the discharge valve and starting the discharge pump.

[0028] In some specific embodiments, reference 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 therein. An auxiliary heating device 54 is installed along the wall of the reflux pipe 51. By activating the reflux pump and opening the reflux valve, the pump's suction effect circulates the solution, accelerating urea dissolution and promoting uniform dispersion. Furthermore, the auxiliary heating device reduces heat loss, maintains solution temperature, and effectively prevents crystallization. Specifically, the auxiliary heating device 54 is an electric heating cable wound along the reflux pipe.

[0029] As an improved implementation method, refer to Figure 1 、 Figure 2 、 Figure 4 and Figure 5 A magnetic drive turntable 17 is fixed to the bottom of the rotating shaft 15, and a magnetic stirring device 18 is provided at the lower part of the fine mixing chamber 14 below the magnetic drive turntable 17. The magnetic drive turntable 17 is connected to the magnetic stirring device 18 by magnetic attraction and drives the magnetic stirring device 18 to rotate. Due to the use of magnetic drive, the stirring paddle located in the preliminary mixing chamber and the magnetic stirring device located in the fine mixing chamber can be linked together, so that synchronous rotation is achieved under the impact of the reflux water column to stir the solution, which has a good stirring and mixing effect and can simplify the stirring structure. Specifically, the lower part of the fine mixing chamber 14 has a conical discharge stirring space, and the magnetic stirring device 18 is installed in the discharge stirring space.

[0030] In some specific embodiments, such as Figure 4 As shown, the magnetic stirring device 18 includes a magnetic driven turntable 182 rotatably mounted on the bottom wall of the inner cylinder 11 via a fixed shaft 181, and a plurality of stirring blades 183 fixed to the side walls of the magnetic driven turntable 182. The fixed shaft 181 is coaxial with the rotating shaft 15. The magnetic drive turntable 17 is provided with a first magnet block 171, and the magnetic 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 mounted on the magnetic drive turntable 17, and the polarity of the four first magnet blocks 171 near the magnetic driven turntable 182 is NSNS in sequence. Four second magnet blocks 184 are correspondingly mounted on the magnetic driven turntable 182, and the polarity of the four second magnet blocks 184 near the magnetic drive turntable 17 is SNSN in sequence. This ensures a good magnetic linkage between the magnetic drive turntable and the magnetic driven turntable, preventing demagnetization.

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

[0032] refer to Figures 1 to 5 , the working process of the present invention is as follows: During use, the required amount of water is first pumped into the mixing drum 1 via 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 turned on to maintain the temperature, and the ultrasonic generator 191 is turned on. Next, the urea to be dissolved is quantitatively added to the mixing drum 1, and the main heating device 113 is turned on to prevent crystallization, and ultrasonic circulating stirring is implemented. The urea is initially stirred, mixed and dissolved with water in the preliminary mixing chamber 13, and then flows into the peripheral fine mixing chamber 14 under the stirring and centrifugal action of the stirring paddle 152 for further mixing. After ultrasonic cavitation, the dissolution and uniform dispersion of the urea are promoted. At the same time, the magnetic stirring device 18 located at the bottom of the fine mixing chamber 14 also further stirs and mixes the solution to improve the urea dissolution effect.

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

[0034] After the preset time has passed, the preparation of the urea solution is completed, the ultrasound, heating and reflux pumping are turned off, and the prepared urea solution is discharged through the drain pipe 42 .

[0035] It should be noted that the ultrasonic vibration plate, ultrasonic generator, water inlet pump, flow meter, water inlet valve, screw conveyor, discharge valve, discharge pump, reflux pump, reflux valve, PLC controller, temperature sensor, electric heating tube, electric heating jacket, electric heating tape and other components used in the present invention are all electrical structures in the prior art. Those skilled in the art can use and install these electrical structures according to the concept of the present invention, so the present invention will not go into details about their specific structural details.

[0036] The above embodiments are merely illustrative of the concepts and technical solutions of the present invention and are not intended to limit the present invention. Anyone skilled in the art may 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 one of ordinary skill in the art without departing from the spirit and technical concepts disclosed herein are intended to be covered by the claims of the present invention.

[0037] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each implementation method can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. An automatic preparation system for urea solution for denitrification of biomass boilers, comprising a mixing drum and a control device, characterized in that: The mixing drum includes an inner drum and an outer drum distributed coaxially, the inner drum forming a preliminary mixing chamber, and a fine mixing chamber formed between the inner drum and the outer drum; a water supply device and a urea input device respectively connected to the preliminary mixing chamber are provided on the top of the mixing drum, and a liquid discharge device connected to the fine mixing chamber is provided at the bottom of the mixing drum; a plurality of guide holes connecting the preliminary mixing chamber and the fine mixing chamber are opened on the side wall of the inner drum; a rotating shaft coaxially distributed with the inner drum is rotatably installed in the inner cavity of the preliminary mixing chamber, a driving impeller is fixedly provided on the upper part of the rotating shaft, and at least one stirring paddle is fixedly provided 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 is provided with a plurality of nozzles for spraying water toward the driving impeller, a reflux port connected to the fine mixing chamber is provided at the lower part of the outer drum, and a reflux device is connected between the reflux port and the water spray pipe.

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

3. The automatic preparation system of urea solution for denitrification of biomass boiler according to claim 1, characterized in that: The urea input device includes a urea input port arranged on the top of the mixing drum, a urea storage tank for storing urea granules, and a screw conveyor with a 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.

4. The automatic preparation system of urea solution for denitrification of biomass boiler according to claim 3 is characterized in that: The bottom of the urea storage tank is provided with a conical lower hopper, and the side wall of the lower hopper is provided with a preheating device for preheating urea.

5. The automatic preparation system of urea solution for denitrification of biomass boiler according to claim 1, characterized in that: The liquid discharge device includes a discharge port arranged at the bottom of the outer cylinder and a liquid discharge pipe connected to the discharge port, and the liquid discharge pipe is installed with a discharge valve and a discharge pump.

6. The automatic preparation system of urea solution for denitrification of biomass boiler according to claim 1, characterized in that: The reflux device comprises a reflux pipe, 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.

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

8. The automatic preparation system of urea solution for denitrification of biomass boiler according to claim 7, 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 a plurality of stirring blades fixed on the side walls of the magnetic driven turntable. The fixed shaft and the rotating shaft are coaxially distributed. The magnetic drive turntable is provided with a first magnet block, and the magnetic driven turntable is provided with a second magnet block that is magnetically attracted to and cooperates with the first magnet block.

9. The automatic preparation system of urea solution for denitrification of biomass boiler according to claim 1, characterized in that: The inner wall of the outer cylinder is provided with an ultrasonic vibration plate connected to the ultrasonic generator, and the outer wall of the inner cylinder is provided with a reflection plate.

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

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