PNCR denitration system

Abstract

The utility model relates to the technical field of boiler denitration, in particular to a PNCR denitration system which comprises a discharging hopper, a spiral conveyor is connected to the lower portion of the discharging hopper, an outlet of the spiral conveyor is connected with a three-way pipe, one end of the three-way pipe is connected with a draught fan, and the other end of the three-way pipe is connected with a material conveying pipe. The draught fan blows air to the material conveying pipe and passes through the connecting position of the spiral conveyor and the three-way pipe, the end, away from the draught fan, of the material conveying pipe is connected with an air guide pipe, the air guide pipe comprises a pipe body and a spiral blade arranged in the pipe body, one end of the pipe body is used for being connected with the material conveying pipe, and the other end of the pipe body is used for being connected with a boiler. The axis of the spiral blade coincides with the axis of the pipe body, and the spiral blade is fixed to the inner wall of the pipe body. The flue gas denitration device has the effects that the denitration agent can be in contact with nitric oxide in flue gas for a longer time, and the reaction efficiency is improved.

Description

Technical Field

[0001] The present application relates to the technical field of boiler denitration, and in particular to a PNCR denitration system. Background Art

[0002] Nitrogen oxides contained in the flue gas generated by industrial boilers or power station boilers need to be removed to improve the quality of flue gas emissions and reduce pollution to the environment. PNCR technology or SNCR technology can be used to remove nitrogen oxides in flue gas. PNCR technology is a polymer denitrification technology. Since the denitrification agent used is a solid polymer material as the main powder mixture, the denitrification agent is sprayed into the denitrification reaction zone. The reaction temperature is 450℃-1000℃, and the removal efficiency of nitrogen oxides can reach 50%-90%, and the operation is stable.

[0003] The related technology discloses a polymer denitrification agent conveying device, including a polymer denitrification agent storage bin, a polymer denitrification agent conveyor, a gas-material distributor and a polymer material spray gun. The polymer denitrification agent conveyor includes a material input end, a gas input end and a gas-material mixing output end. The material input end is connected to the output end of the polymer denitrification agent storage bin, the gas-material distributor is connected to the material input end and the control valve of the gas input end of the polymer denitrification agent conveyor, and the input end of the polymer material spray gun is connected to the gas-material mixing output end of the polymer denitrification agent conveyor. The polymer denitrification agent conveying device can automatically spray the polymer denitrification agent into the flue gas, react with nitrogen oxides, and finally generate nitrogen and water.

[0004] However, the above structure directly sprays the denitrification agent made of polymer materials, which has a short reaction time with the flue gas and requires a large amount of denitrification agent. Utility Model Content

[0005] In order to enable the denitrification agent to be in contact with nitrogen oxides in the flue gas for a longer time and improve the reaction efficiency, the present application provides a PNCR denitrification system.

[0006] The present application provides a PNCR denitration system, which adopts the following technical solution:

[0007] A PNCR denitration system includes a lower hopper, a screw conveyor is connected below the lower hopper, a tee is connected to the outlet of the screw conveyor, one end of the tee is connected to a fan, and the other end is connected to a feed pipe, the fan blows air to the feed pipe and passes through the connection position between the screw conveyor and the tee, the feed pipe is connected to an air guide pipe at one end away from the fan, the air guide pipe includes a pipe body and a spiral blade arranged inside the pipe body, one end of the pipe body is used to connect to the feed pipe, and the other end is used to connect to a boiler, the axis of the spiral blade coincides with the axis of the pipe body, and the spiral blade is fixed to the inner wall of the pipe body.

[0008] By adopting the above technical solution, when in use, a denitrifier is placed in the lower hopper, and the denitrifier moves to the position of the three-way pipe through the screw conveyor. At the same time, the fan also generates an airflow to move in the direction of the conveying pipe. At this time, the airflow contacts the denitrifier when passing through the position of the three-way pipe and takes away the denitrifier, so that the denitrifier is mixed in the airflow. When the denitrifier moves to the position of the air duct with the airflow, the airflow is affected by the spiral blades, and the spiral blades will rotate the airflow. Therefore, when entering the boiler from the air duct, the denitrifier will maintain a rotating state and move in the boiler, thereby making the denitrifier contact with the nitrogen oxides in the flue gas for a long time, so that more nitrogen oxides are adsorbed on the denitrifier, and the reaction efficiency with the nitrogen oxides in the flue gas is improved.

[0009] Preferably, a feed hopper is arranged above the lower hopper, a valve is arranged between the feed hopper and the lower hopper, and the feed hopper is connected to a vacuum conveying device, which is used to convey the denitrification agent into the feed hopper.

[0010] By adopting the above technical solution, a valve is arranged between the upper and lower hoppers. When the valve is in a closed state, the vacuum conveying device generates airflow in the feed hopper by vacuuming and sucks the denitrification agent into the feed hopper, thereby making it more convenient to load the denitrification agent.

[0011] Preferably, the vacuum conveying device comprises a silo, a vacuum pump and a filter, the silo is connected to a feed pipe, the filter is installed on the silo, and the suction end of the vacuum pump is connected to the silo through the filter.

[0012] By adopting the above technical solution, the vacuum pump generates airflow, which is formed through the filter, the silo and the feed pipe. When there is a denitrifier in the feed pipe, the airflow will enter the silo along the feed pipe and then be blocked by the filter, so that the denitrifier remains in the silo.

[0013] Preferably, the silo includes a cyclone portion, a lower material portion and an upwind portion, the cyclone portion is truncated cone-shaped, and the lower material portion is connected to the bottom of the cyclone portion, the upwind portion is connected to the top of the cyclone portion, a connecting pipe is provided on the side wall of the cyclone portion, the connecting pipe is provided along the tangential direction of the side wall of the cyclone portion, the feed pipe is connected to the connecting pipe, an exhaust pipe is provided in the center of the silo, and the exhaust pipe is connected to the filter.

[0014] By adopting the above technical solution, a connecting pipe is provided on the side wall of the cyclone part, and the connecting pipe is connected to the feed pipe, so that the cyclone part enters the airflow and rotates along the edge of the cyclone part, so that the denitrification agent can be separated from the airflow under the action of centrifugal force, thereby reducing the clogging of the filter.

[0015] Preferably, a filter element is provided in the upwind portion, a detachable cover is provided on the top of the upwind portion, and the upper end of the exhaust pipe is connected to the lower part of the upwind portion through the filter element.

[0016] By adopting the above technical solution, a filter element is arranged in the upwind part. When the airflow in the exhaust pipe is first filtered by the filter element and then enters the filter, the clogging of the filter is reduced. At the same time, the filter element can also be removed from the cover for maintenance.

[0017] Preferably, a dividing cylinder is provided in the cyclone part, and the dividing cylinder is arranged in a cone shape. The diameter of the lower end of the dividing cylinder is larger than the diameter of the exhaust pipe. The exhaust pipe is passed through the dividing cylinder, and the position of the lower end of the dividing cylinder is lower than the position where the connecting pipe is arranged. The larger conical end of the dividing cylinder is arranged upward and fixedly connected to the cyclone part.

[0018] By adopting the above technical solution, a splitter barrel is arranged in the cyclone section. When the airflow rotates in the cyclone barrel, it enters the upwind section from the lower end of the splitter barrel. Thus, the splitter barrel can reduce the denitrification agent entering the upwind section and reduce the maintenance frequency of the filter element.

[0019] Preferably, a stirring device is provided in the feed hopper, the stirring device includes a stirring shaft, a worm gear reducer and a driving motor, the stirring shaft is vertically arranged in the center of the feed hopper, the output shaft of the worm gear reducer is fixedly connected to the stirring shaft, the driving motor is fixed on the feed hopper, the output shaft of the driving motor is coaxially fixed with the input shaft of the worm gear reducer, a stirring blade is fixedly provided on the stirring shaft, and the lower edge of the stirring blade is in contact with the inner wall of the feed hopper.

[0020] By adopting the above technical solution, when the driving motor is working, the driving motor drives the stirring shaft to rotate through the worm gear reducer. When the stirring shaft rotates, it can drive the stirring blades, so that the stirring blades mix the denitrification agent in the feed hopper, and at the same time can reduce the denitrification agent sticking to the inner wall of the feed hopper.

[0021] Preferably, the stirring blade is spiral-shaped, the feed hopper is configured to be conical, and the larger conical end of the feed hopper faces upward.

[0022] By adopting the above technical solution, the stirring blade is spiral-shaped, so that the stirring blade can stir the denitrification agent upward when working, and can also transport the denitrification agent downward when reversing. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present application;

[0024] Figure 2 is a schematic diagram of the structure of the air guide duct in an embodiment of the present application;

[0025] Figure 3 This is a schematic diagram of the internal structure of the silo in the embodiment of the present application;

[0026] Figure 4It is a schematic diagram of the internal structure of the feed hopper in the embodiment of the present application.

[0027] Explanation of the reference numerals: 1. feed hopper; 2. discharge hopper; 3. screw conveyor; 4. feed pipe; 41. tee pipe; 42. fan; 5. valve; 6. vacuum conveying device; 61. silo; 611. cyclone section; 612. discharge section; 613. upwind section; 614. connecting pipe; 615. exhaust pipe; 616. dividing cylinder; 62. vacuum pump; 63. filter; 64. feed pipe; 65. filter element; 66. cover body; 7. air guide duct; 71. pipe body; 72. spiral blade; 8. stirring device; 81. stirring shaft; 82. worm gear reducer; 83. drive motor; 84. stirring blade. DETAILED DESCRIPTION

[0028] The following is combined with Figure 1-4 This application is described in further detail.

[0029] The present application embodiment discloses a PNCR denitration system, referring to Figure 1 and Figure 2 , including a feed hopper 1, a lower hopper 2, a screw conveyor 3 and a feeding pipe 4, a valve 5 is arranged between the feed hopper 1 and the lower hopper 2, the feed hopper 1 adopts a vacuum conveying device 6 for loading, the lower hopper 2 is connected to the bottom of the valve 5, and the valve 5 is opened to make the denitrification agent in the feed hopper 1 fall into the lower hopper 2, the screw conveyor 3 is installed at the lower end of the lower hopper 2, the screw conveyor 3 is arranged horizontally, the feed end of the screw conveyor 3 is connected to the lower end of the lower hopper 2, the discharge end of the screw conveyor 3 is connected to the feeding pipe 4, a three-way pipe 41 is installed on the feeding pipe 4, the feeding pipe 4 is connected to the screw conveyor 3 through the three-way pipe 41, and the three-way pipe 41 is also connected to the fan 42, the blowing direction of the fan 42 passes through the position of the three-way pipe 41 and the screw conveyor 3, and at the same time, an air guide pipe 7 is arranged at one end of the three-way pipe 41 away from the fan 42. During operation, the screw conveyor 3 conveys the denitrification agent into the three-way pipe 41, and the fan 42 blows the air in the direction of the air guide 7, so that the air flow mixes the denitrification agent in the air when passing through the connection between the screw conveyor 3 and the three-way pipe 41, and the denitrification agent moves along the air flow to the air guide 7. One end of the air guide 7 is connected to the feed pipe 4, and the other end is used to be connected to the boiler exhaust position, so that the denitrification agent can be automatically transported to the boiler exhaust position, so that the denitrification agent contacts the flue gas and reacts after adsorbing the nitrogen oxides.

[0030] The air duct 7 includes a tube body 71 and a spiral blade 72 arranged inside the tube body 71. The spiral blade 72 is coaxially arranged with the tube body 71 and fixed on the inner wall of the tube body 71, so that the tube body 71 and the spiral blade 72 guide the airflow, so that the airflow moves in a spiral in the air duct 7. One end of the tube body 71 is connected to the feed pipe 4, and the other end is connected to the boiler, so that the airflow flowing out of the air duct 7 is in a spiral state when entering the boiler, and the denitrification agent also contacts the flue gas in a spiral state, thereby increasing the contact time between the denitrification agent and the nitrogen oxides, so that more nitrogen oxides are adsorbed on the denitrification agent for reaction.

[0031] refer to Figure 1 The vacuum conveying device 6 includes a silo 61, a vacuum pump 62 and a filter 63. A feed pipe 64 is connected to the silo 61. One end of the feed pipe 64 is connected to the silo 61, and the other end is used to absorb the denitrification agent. The filter 63 is installed on the silo 61, and the suction end of the vacuum pump 62 is connected to the silo 61 through the filter 63. When working, the vacuum pump 62 generates airflow in the feed pipe 64 through the silo 61, so that the denitrification agent can be automatically sucked into the silo 61, and then the denitrification agent is retained in the silo 61 through the filter 63, so that the denitrification agent can be loaded more conveniently.

[0032] refer to Figure 3 The silo 61 includes a cyclone portion 611, a lower material portion 612 and an upwind portion 613. The cyclone portion 611 is located between the lower material portion 612 and the upwind portion 613, and the lower material portion 612 is located below the cyclone portion 611, and the upwind portion 613 is located above the cyclone portion 611. A connecting pipe 614 is connected to the side of the cyclone portion 611. The connecting pipe 614 is used to connect the feed pipe 64. The connecting pipe 614 is arranged along the tangent direction of the side wall of the cyclone portion 611. The cyclone portion 611 is provided with a circular Trapezoid-shaped, when the denitrifying agent enters into the cyclone part 611, it rotates along the inner wall of the cyclone part 611, so that the denitrifying agent and the airflow are separated, and the airflow is concentrated in the center of the cyclone part 611. An exhaust pipe 615 is arranged in the center of the silo 61, and one end of the exhaust pipe 615 is used to install the filter 63 and is connected to the vacuum pump 62, so that the airflow carrying the denitrifying agent is first separated by the cyclone part 611, and then blocked by the filter 63, thereby reducing the blockage of the filter 63 and reducing the frequency of maintenance.

[0033] The lower material part 612 is connected to the lower part of the cyclone part 611, so that the denitrification agent left in the cyclone part 611 falls into the lower material part 612 under the action of gravity, and the lower end of the lower material part 612 is connected to the feed hopper 1. A filter element 65 is arranged in the upwind part 613, and the top of the upwind part 613 is open and is provided with a detachable cover body 66 for sealing, and the cover body 66 can be connected to the upwind part 613 by bolts. The filter element 65 can be taken out from the top opening of the upwind portion 613. The outside of the filter element 65 contacts the inner wall of the upwind portion 613. The middle of the filter element 65 is used to penetrate the exhaust pipe 615. The upper end of the exhaust pipe 615 penetrates the filter element 65. The exhaust pipe 615 is connected to the upwind portion 613 at the upper position of the upwind portion 613, so that the filter element 65 filters the airflow at the lower part of the upwind portion 613 and enters the upper part of the upwind portion 613 and is discharged from the exhaust pipe 615, so that the filter element 65 blocks the denitrification agent again, making it easier to open the cover 66 for maintenance when the filter element 65 is blocked. The exhaust pipe 615 extends downward away from the upwind portion 613 and extends from the side wall of the lower material portion 612. A split barrel 616 is arranged inside the cyclone section 611. The split barrel 616 is conical, and the larger end of the split barrel 616 is arranged upward. The split barrel 616 is coaxially arranged with the cyclone section 611. The diameter of the smaller end of the split barrel 616 is larger than the diameter of the exhaust pipe 615, so that the exhaust pipe 615 passes through the center of the split barrel 616. The upper end of the split barrel 616 is sealed with the cyclone section 611, and the lower end of the split barrel 616 is below the connecting pipe 614, so that the airflow rotates in the cyclone barrel and then enters the upwind section 613 from the lower end of the split barrel 616, so that the split barrel 616 first screens the airflow entering the upwind section 613 to reduce the denitrification agent entering the upwind section 613.

[0034] refer to Figure 4 A stirring device 8 is provided in the feed hopper 1, and the feed hopper 1 is configured to be conical, with the large end of the cone of the feed hopper 1 facing upward, and the lower end of the discharge portion 612 is connected to the upper end of the feed hopper 1 and deviates from the center of the feed hopper 1. The stirring device 8 includes a stirring shaft 81, a worm gear reducer 82 and a driving motor 83. The stirring shaft 81 is coaxially arranged with the feed hopper 1, and the stirring shaft 81 is vertically located at the center of the feed hopper 1. The upper end of the stirring shaft 81 is coaxially fixed with the output shaft of the worm gear reducer 82. The driving motor 83 is fixed on the feed hopper 1, and the output shaft of the driving motor 83 is coaxially fixed with the input shaft of the worm gear reducer 82. A plurality of stirring blades 84 are arranged on the stirring shaft 81. The stirring blades 84 are located in the feed hopper 1 so that the denitrification agent entering the feed hopper 1 can be mixed. The stirring blades 84 are arranged in a spiral shape, and the edge movement trajectory of the stirring blades 84 is in contact with the inner wall of the lower part of the feed hopper 1, so that the stirring blades 84 can avoid the denitrification agent from forming a support top, so that the denitrification agent can be discharged smoothly from the feed hopper 1. A stirring device 8 of the same structure can be arranged in the lower hopper 2.

[0035] The working process of this embodiment:

[0036] First, close the valve 5 and open the vacuum pump 62 to allow the denitrification agent to enter the silo 61 along the feed pipe 64 under the action of the airflow, and then enter the feed hopper 1 from the silo 61. Stop the vacuum pump 62 and open the valve 5 to allow the denitrification agent to fall into the lower hopper 2. When it is necessary to add the denitrification agent to the boiler, the screw conveyor 3 conveys the denitrification agent in the lower hopper 2 to the three-way pipe 41. At the same time, due to the action of the fan 42, the denitrification agent is quickly blown out from the air duct 7, so that the denitrification agent enters the boiler in a rotating state, thereby increasing the contact time with the flue gas and adsorbing and reacting the nitrogen oxides.

[0037] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A PNCR denitration system, characterized in that: The invention comprises a lower hopper (2), a screw conveyor (3) is connected below the lower hopper (2), an outlet of the screw conveyor (3) is connected to a three-way pipe (41), one end of the three-way pipe (41) is connected to a fan (42), and the other end is connected to a feed pipe (4), the fan (42) blows air to the feed pipe (4) and passes through a connection position between the screw conveyor (3) and the three-way pipe (41), one end of the feed pipe (4) away from the fan (42) is connected to an air guide pipe (7), the air guide pipe (7) comprises a pipe body (71) and a spiral blade (72) arranged inside the pipe body (71), one end of the pipe body (71) is used to connect to the feed pipe (4), and the other end is used to connect to a boiler, the axis of the spiral blade (72) coincides with the axis of the pipe body (71), and the spiral blade (72) is fixed to the inner wall of the pipe body (71).

2. A PNCR denitration system according to claim 1, characterized in that: A feed hopper (1) is arranged above the lower hopper (2), a valve (5) is arranged between the feed hopper (1) and the lower hopper (2), and the feed hopper (1) is connected to a vacuum conveying device (6), which is used to convey the denitrification agent into the feed hopper (1).

3. A PNCR denitration system according to claim 2, characterized in that: The vacuum conveying device (6) comprises a material bin (61), a vacuum pump (62) and a filter (63); the material bin (61) is connected to a feed pipe (64); the filter (63) is installed on the material bin (61); and the air suction end of the vacuum pump (62) is connected to the material bin (61) via the filter (63).

4. A PNCR denitration system according to claim 3, characterized in that: The silo (61) comprises a cyclone portion (611), a lower material portion (612) and an upwind portion (613); the cyclone portion (611) is in a truncated cone shape, and the lower material portion (612) is connected to the lower part of the cyclone portion (611); the upwind portion (613) is connected to the upper part of the cyclone portion (611); a connecting pipe (614) is provided on the side wall of the cyclone portion (611); the connecting pipe (614) is provided along the tangent direction of the side wall of the cyclone portion (611); the feed pipe (64) is connected to the connecting pipe (614); an exhaust pipe (615) is provided at the center of the silo (61); the exhaust pipe (615) is connected to the filter (63).

5. A PNCR denitration system according to claim 4, characterized in that: A filter element (65) is provided in the upwind portion (613), a detachable cover (66) is provided on the top of the upwind portion (613), and the upper end of the exhaust pipe (615) is connected to the lower part of the upwind portion (613) via the filter element (65).

6. A PNCR denitration system according to claim 5, characterized in that: A split tube (616) is arranged in the cyclone portion (611), the split tube (616) being arranged in a conical shape, the diameter of the lower end of the split tube (616) being larger than the diameter of the exhaust pipe (615), the exhaust pipe (615) being passed through the split tube (616), and the position of the lower end of the split tube (616) being lower than the position where the connecting pipe (614) is arranged, and the larger conical end of the split tube (616) is arranged upwards and fixedly connected to the cyclone portion (611).

7. A PNCR denitration system according to claim 2, characterized in that: The feed hopper (1) is provided with a stirring device (8), the stirring device (8) comprising a stirring shaft (81), a worm gear reducer (82) and a drive motor (83), the stirring shaft (81) being vertically arranged at the center of the feed hopper (1), the output shaft of the worm gear reducer (82) being fixedly connected to the stirring shaft (81), the drive motor (83) being fixed on the feed hopper (1), the output shaft of the drive motor (83) being coaxially fixed to the input shaft of the worm gear reducer (82), and a stirring blade (84) being fixedly arranged on the stirring shaft (81), and the lower edge of the stirring blade (84) being in contact with the inner wall of the feed hopper (1).

8. A PNCR denitration system according to claim 7, characterized in that: The stirring blade (84) is spiral-shaped, and the feed hopper (1) is arranged in a conical shape, with the larger end of the feed hopper (1) facing upward.

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