CN211040944U - Flue gas recirculation system for low-nitrogen boiler - Google Patents
Flue gas recirculation system for low-nitrogen boiler Download PDFInfo
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- CN211040944U CN211040944U CN201921851069.XU CN201921851069U CN211040944U CN 211040944 U CN211040944 U CN 211040944U CN 201921851069 U CN201921851069 U CN 201921851069U CN 211040944 U CN211040944 U CN 211040944U
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- flue gas
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Abstract
The utility model relates to a flue gas recirculation system used on a low-nitrogen boiler, which comprises a fan, a burner, a boiler and an economizer, wherein the air inlet of the fan is connected with a mixing cylinder, a flue gas circulation pipeline is arranged on a flue gas outlet pipeline of the boiler and is connected with the mixing cylinder; the flue gas circulating pipeline is provided with a flow regulating mechanism; the flow regulating mechanism comprises a rotating shaft, a baffle plate and a servo motor, wherein the rotating shaft is parallel to the central axis of the cross section of the flue gas circulating pipeline, the baffle plate is matched with the cross section of the flue gas circulating pipeline, and the servo motor controls the rotating shaft to rotate axially; the two ends of the rotating shaft penetrate through the round holes corresponding to the two positions on the pipe wall of the flue gas circulation pipeline, and the baffle is arranged inside the flue gas circulation pipeline. Compared with the prior art, the utility model has the advantages of the flue gas circulation volume is adjusted accurately conveniently, effectively reduces nitrogen oxide emission value.
Description
Technical Field
The utility model belongs to the technical field of heat energy power and boiler and specifically relates to a flue gas recirculation system for on low-nitrogen boiler is related to.
Background
In order to effectively control the emission of nitrogen oxides of a gas boiler and reduce the secondary generation of PM2.5, the emission standard of nitrogen oxides in boiler flue gas is not higher than 50 mg/cubic meter in many areas, and the emission temperature of the boiler flue gas is preferably lower than 110 ℃. Most of the existing boiler emission standards can not reach the emission standards specified in the latest regions, the exhaust gas temperature is difficult to be reduced below the standard value, the most basic technology at present is to integrally replace a boiler or a burner, and on the one hand, the reconstruction cost of the integral replacement equipment facility is high, and the construction period is long; on the other hand, the exhaust gas temperature of the boiler is too high, which causes waste of heat energy. In addition, the flue gas circulation volume of the existing boiler cannot be flexibly adjusted in the circulating device, the flue gas circulation volume cannot be adaptively adjusted according to different emission standards, or some circulating devices adjust the circulating flue gas volume through butterfly valves, but the butterfly valves are poor in adjustment accuracy, the valves with high accuracy are expensive, and the economical and practical requirements cannot be met.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a flue gas recirculation system that flue gas is adjusted easily and is used for on low-nitrogen boiler in order to overcome the difficult defect of flue gas volume regulation that above-mentioned prior art exists.
The purpose of the utility model can be realized through the following technical scheme:
a flue gas recirculation system for a low-nitrogen boiler comprises a fan, a burner, a boiler and an economizer, wherein an air inlet of the fan is connected with a mixing cylinder, a flue gas outlet pipeline of the boiler is provided with a flue gas circulation pipeline, and the flue gas circulation pipeline is connected with the mixing cylinder; the flue gas circulating pipeline is provided with a flow regulating mechanism; the flow regulating mechanism comprises a rotating shaft, a baffle plate and a servo motor, wherein the rotating shaft is parallel to the central axis of the cross section of the flue gas circulating pipeline, the baffle plate is matched with the cross section of the flue gas circulating pipeline, and the servo motor controls the rotating shaft to rotate axially; the two ends of the rotating shaft penetrate through the round holes corresponding to the two positions on the pipe wall of the flue gas circulation pipeline, and the baffle is arranged inside the flue gas circulation pipeline.
The utility model discloses design on original combustor, through installing Flue Gas Recirculation (FGR) device additional, do not need whole change equipment facility just can reach the effect of effective control nitrogen oxide emission value, practiced thrift the cost greatly.
The utility model discloses a design a simple structure's regulating plate, the rotation angle through the regulating plate changes the circulation sectional area of flue gas circulation pipeline to through the rotation angle of servo motor control regulating plate, utilize servo motor to make control speed, the very accurate characteristic of position precision realizes the accurate regulation to flue gas circulation volume, is favorable to improving the regulation precision.
Fresh air and circulating flue gas are mixed through the mixing cylinder and then enter the combustor, so that the uniformity of the gas entering the combustor is improved, and the combustion quality is ensured; the oxygen content of combustion air is reduced after the flue gas and the fresh air are premixed, so that the combustion temperature is reduced, the flue gas emission temperature is reduced, and the heat energy waste is reduced.
The flue gas circulating pipeline is a circular pipeline, and the baffle is a circular baffle.
The shell of the servo motor is fixed on the outer side of the pipe wall of the flue gas circulation pipeline, and an output shaft of the servo motor is connected with the rotating shaft.
A connecting rod is fixed on the rotating shaft positioned outside the flue gas circulating pipeline and is vertical to the rotating shaft; a connecting bolt is fixed below the end part of the connecting rod and is parallel to the rotating shaft; the smoke circulating pipeline is fixedly connected with a fan-shaped connecting plate, and the surface of the fan-shaped connecting plate is provided with a strip-shaped through hole which is arranged along the arc direction of a fan shape; the connecting bolt penetrates through the strip-shaped through hole and is fixed on the fan-shaped connecting plate through the matched nuts positioned on the upper surface and the lower surface of the fan-shaped connecting plate.
After servo motor accomplished the location, realize the fixed of connecting rod and pivot through connecting bolt and supporting nut to make the baffle keep at fixed rotation angle, prevent that servo motor from opening the atress for a long time, influence servo motor's life-span.
The fan, the burner, the boiler, the economizer and the flue gas circulating pipe are provided with two sets, and the two sets of devices are symmetrically arranged.
The flow regulating mechanism is arranged at one end of the flue gas circulating pipeline close to the mixing cylinder.
The flue gas circulating pipeline is provided with a heat preservation layer, heat preservation treatment is carried out on FGR, and flue gas condensate water is effectively prevented from being generated.
The utility model discloses still include the P L C controller, be equipped with nitrogen oxide sensor on the exhaust pipe of boiler, P L C controller and servo motor and nitrogen oxide sensor signal connection, through the P L C controller, the automatic nitrogen oxide sensor content according to discharging fume of realization system is adjusted.
An air inlet of the mixing cylinder is connected with an air heater, a tube pass of the air heater is filled with air, a shell pass inlet of the air heater is connected with a water outlet pipe of the boiler, and a shell pass outlet of the air heater is connected with a water inlet pipe of the boiler.
Compared with the prior art, the utility model has the advantages of it is following:
(1) the servo motor drives the adjusting plate to realize efficient and accurate adjustment of the flue gas circulation amount, the flue gas circulation amount is accurately adjusted, the adjustment precision is improved, and different emission requirements can be met by controlling the recirculation amount of the flue gas;
(2) the circulating flue gas and air are premixed, so that the gas entering the combustor is more uniform, the combustion uniformity is facilitated, and the combustion quality is improved;
(3) when the system is stable, the position of the adjusting plate is fixed through the matched connecting rod, connecting bolt, nut and fan-shaped connecting plate, and energy waste and damage of the servo motor caused by long-time work of the servo motor are avoided;
(4) the flue gas circulating pipeline FGR is subjected to heat preservation treatment, so that flue gas condensate water is effectively prevented from being generated;
(5) the hot water or steam generated by the boiler is utilized to preheat the fresh air, so that the temperature of the gas entering the combustor is ensured, and the combustion effect is improved.
Drawings
Fig. 1 is a schematic structural view of the present invention;
FIG. 2 is a schematic diagram of the operation of the present invention;
fig. 3 is a schematic view of the structure of the middle flow rate adjusting mechanism of the present invention;
FIG. 4 is a schematic structural view of a middle fan-shaped connecting plate according to the present invention;
in the figure, 1 is a boiler, 2 is a mixing drum, 3 is a fan, 4 is a burner, 5 is an economizer, 6 is a baffle, 7 is a rotating shaft, 8 is a servo motor, 9 is a connecting rod, 10 is a connecting bolt, 11 is a nut, 12 is a fan-shaped connecting plate, 13 is a flue gas circulating pipeline, 14 is a long-strip-shaped through hole, 15 is an air inlet, 16 is flue gas, and 17 is circulating flue gas.
Detailed Description
The present invention will be described in detail with reference to the following embodiments. The following examples will assist those skilled in the art in further understanding the present invention, but are not intended to limit the invention in any way. It should be noted that various changes and modifications can be made by one skilled in the art without departing from the spirit of the invention. These all belong to the protection scope of the present invention.
Examples
A kind of gas recirculation system used in low-nitrogen boiler, as shown in figure 1, along the air flow direction, including mixing cylinder 2, blower 3, burner 4, boiler 1, coal economizer 5 connected sequentially, there are gas circulation pipelines 13 on the flue gas outlet pipeline of the boiler 1, the gas circulation pipeline 13 is connected with mixing cylinder 2, there are air intakes 15 on the mixing cylinder 2, the fresh air enters the system from the air intake 15; the fan 3, the burner 4, the boiler 1, the economizer 5 and the flue gas circulating pipe 13 are provided with two sets which are symmetrically arranged. An air inlet of the mixing cylinder 2 is connected with an air heater, the tube side of the air heater is filled with air, a shell side inlet of the air heater is connected with a water outlet pipe of the boiler 1, and a shell side outlet of the air heater is connected with a water inlet pipe of the boiler 1.
As shown in FIG. 2, the principle of the present invention is that the circulating flue gas 17 from the air and flue gas circulating pipe 13 is mixed and enters the burner 4 to provide oxygen for the fuel and is burned in the furnace of the boiler 1, and then a part of the generated flue gas 16 is mixed with fresh air through the flue gas circulating pipe 13 and is discharged partially.
Flue gas circulating pipe 13 is circular pipeline to be equipped with the heat preservation on the flue gas circulating pipe 13, be equipped with flow control mechanism on this circular pipeline, flow control mechanism locates the one end that flue gas circulating pipe 13 is close to mixing drum 2. As shown in fig. 3, the flow regulating mechanism comprises a rotating shaft on a central axis parallel to the cross section of the flue gas circulating pipeline 13, a circular baffle 6 matched with the cross section of the flue gas circulating pipeline 13, and a servo motor 8 for controlling the rotating shaft to rotate axially; two ends of the rotating shaft penetrate through two circular holes corresponding to the pipe wall of the flue gas circulating pipeline 13, and the baffle 6 is arranged inside the flue gas circulating pipeline 13; the shell of the servo motor 8 is fixed on the outer side of the pipe wall of the flue gas circulation pipeline 13, and the output shaft of the servo motor 8 is connected with the rotating shaft; a connecting rod 9 is fixed on the rotating shaft positioned outside the smoke circulating pipeline 13, and the connecting rod 9 is vertical to the rotating shaft; a connecting bolt 10 is fixed below the end part of the connecting rod 9, and the connecting bolt 10 is parallel to the rotating shaft; as shown in fig. 4, a fan-shaped connecting plate 12 is fixedly connected to the flue gas circulation pipe 13, and a strip-shaped through hole 14 arranged along the arc direction of the fan shape is formed in the surface of the fan-shaped connecting plate 12; connecting bolt 10 passes through this rectangular shape through-hole 14 to be fixed in fan-shaped connecting plate 12 on through the supporting nut 11 that is located fan-shaped connecting plate 12 upper and lower surface, through setting up the fixed subassembly of baffle among the supporting adjustment mechanism, can be after the steady operation of system, with baffle position mechanical fixation, thereby avoid servo motor to move for a long time.
The system of the embodiment is provided with a P L C controller, a nitrogen oxide sensor is arranged on a smoke exhaust pipeline of the boiler 1, the P L C controller is in signal connection with the servo motor 8 and the nitrogen oxide sensor and can achieve automatic adjustment in an adjustment stage, if the nitrogen oxide sensor detects that the content of nitrogen oxide is large and does not meet emission standards, the servo motor 8 is controlled to increase the amount of circulating smoke and reduce the nitrogen oxide to be below the emission standards, the nitrogen oxide sensor is an online nitrogen oxide detector and is suitable for continuous online detection of the concentration of the nitrogen oxide in various industrial environments and special environments, a commercially available machine is selected, for example, an OS6-NOx online nitrogen oxide detector of Osonjie OUSJ manufacturers, and the P L C controller is a controller commonly used in the field of chemical automation.
The utility model carries out design research on the original burner, and can achieve the effect of effectively controlling the emission value of nitrogen oxide without integrally replacing equipment and facilities by additionally arranging the FGR flue gas recirculation device, thereby greatly saving the cost; the flue gas circulating pipeline FGR is subjected to heat preservation treatment, so that flue gas condensate water is effectively prevented from being generated; by additionally arranging the FGR baffle and the servo motor, different emission requirements can be met by controlling the recirculation quantity of the flue gas; the oxygen content of combustion air is reduced after the flue gas and the fresh air are premixed, so that the combustion temperature is reduced, the flue gas emission temperature is reduced, and the heat energy waste is reduced.
The foregoing description of the specific embodiments of the invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes and modifications may be made by those skilled in the art within the scope of the appended claims without departing from the spirit of the invention.
Claims (9)
1. A flue gas recirculation system used on a low-nitrogen boiler comprises a fan (3), a burner (4), a boiler (1) and an economizer (5), and is characterized in that,
the air inlet of the fan (3) is connected with a mixing drum (2), a flue gas circulating pipeline (13) is arranged on a flue gas outlet pipeline of the boiler (1), and the flue gas circulating pipeline (13) is connected with the mixing drum (2); a flow regulating mechanism is arranged on the flue gas circulating pipeline (13); the flow regulating mechanism comprises a rotating shaft, a baffle plate (6) and a servo motor (8), wherein the rotating shaft is parallel to the central axis of the cross section of the flue gas circulating pipeline (13), the baffle plate (6) is matched with the cross section of the flue gas circulating pipeline (13), and the servo motor controls the rotating shaft to rotate axially; two ends of the rotating shaft penetrate through two round holes corresponding to the two positions on the pipe wall of the smoke circulating pipeline (13), and the baffle (6) is arranged inside the smoke circulating pipeline (13).
2. The flue gas recirculation system for a low-nitrogen boiler according to claim 1, wherein the flue gas recirculation pipe (13) is a circular pipe, and the baffle (6) is a circular baffle.
3. The flue gas recirculation system for the low-nitrogen boiler according to claim 1, wherein the casing of the servo motor (8) is fixed outside the pipe wall of the flue gas recirculation pipe (13), and the output shaft of the servo motor (8) is connected with the rotating shaft.
4. The flue gas recirculation system for a low-nitrogen boiler according to claim 1, wherein a connecting rod (9) is fixed on a rotating shaft outside the flue gas recirculation pipe (13), and the connecting rod (9) is perpendicular to the rotating shaft; a connecting bolt (10) is fixed below the end part of the connecting rod (9), and the connecting bolt (10) is parallel to the rotating shaft; the smoke circulating pipeline (13) is fixedly connected with a fan-shaped connecting plate (12), and the surface of the fan-shaped connecting plate (12) is provided with a strip-shaped through hole (14) which is arranged along the arc direction of a fan shape; the connecting bolt (10) penetrates through the long strip-shaped through hole (14) and is fixed on the fan-shaped connecting plate (12) through matched nuts (11) positioned on the upper surface and the lower surface of the fan-shaped connecting plate (12).
5. The flue gas recirculation system for the low-nitrogen boiler is characterized in that the two sets of the fan (3), the burner (4), the boiler (1), the economizer (5) and the flue gas recirculation pipeline (13) are arranged symmetrically.
6. The flue gas recirculation system for the low-nitrogen boiler according to claim 1, wherein the flow regulating mechanism is arranged at one end of the flue gas recirculation pipe (13) close to the mixing drum (2).
7. The flue gas recirculation system for the low-nitrogen boiler as recited in claim 1, wherein the flue gas recirculation pipe (13) is provided with an insulating layer.
8. The flue gas recirculation system for the low-nitrogen boiler is characterized in that the flue gas recirculation system further comprises a P L C controller, a nitrogen oxide sensor is arranged on a smoke exhaust pipeline of the boiler (1), and the P L C controller is in signal connection with a servo motor (8) and the nitrogen oxide sensor.
9. The flue gas recirculation system for the low-nitrogen boiler is characterized in that an air inlet of the mixing drum (2) is connected with an air heater, a tube side of the air heater is filled with air, a shell side inlet of the air heater is connected with a water outlet pipe of the boiler (1), and a shell side outlet of the air heater is connected with a water inlet pipe of the boiler (1).
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921851069.XU CN211040944U (en) | 2019-10-31 | 2019-10-31 | Flue gas recirculation system for low-nitrogen boiler |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921851069.XU CN211040944U (en) | 2019-10-31 | 2019-10-31 | Flue gas recirculation system for low-nitrogen boiler |
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| CN211040944U true CN211040944U (en) | 2020-07-17 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114046501A (en) * | 2021-11-16 | 2022-02-15 | 上海德律风置业有限公司 | Boiler low-ammonia combustion device with improved function |
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2019
- 2019-10-31 CN CN201921851069.XU patent/CN211040944U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114046501A (en) * | 2021-11-16 | 2022-02-15 | 上海德律风置业有限公司 | Boiler low-ammonia combustion device with improved function |
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