KR101593623B1 - Interlocking sensing type proportional controlling boiler connecter with flue gas recirculation damper - Google Patents

Abstract

The present invention relates to an interlocking sensing type proportional control boiler and, more specifically, to an interlocking sensing type proportional control boiler connected to an exhaust gas recirculation damper, which proportionally controls the supply of fuel and the supply of air for combustion by interlocking to a load applied to the boiler and proportionally controls the supply of air for combustion by interlocking to the recirculation of exhaust gas resupplied to a blower, thereby reducing the nitrogen oxide of the exhaust gas without the vibration of the blower or noise. According to the present invention, the interlocking sensing type proportional control boiler minutely controls the supply of air for combustion and recirculation gas according to the load change of fluid as the recirculation flow rate of the exhaust gas is continuously and proportionally controlled by interlocking to the supply of air for combustion, thereby improving combustion efficiency and a fuel consumption rate and minimizing the emission of the nitrogen oxide.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an interlocking-type proportional control boiler connected to an exhaust gas recirculation damper,

More particularly, the present invention relates to a proportional control boiler for controlling the proportional control of the supply of fuel and the supply of combustion air in conjunction with the load applied to the boiler, and the recirculation of the exhaust gas re- To an intermittently-driven proportional-control boiler connected to an exhaust gas recirculation damper capable of reducing nitrogen oxides in the exhaust gas without vibration or noise of the blower by proportionally controlling the supply of air for combustion.

Generally, a boiler is a device that heats a fluid such as water or a fruit through combustion heat generated in a combustion process of fuel, circulates the heated fluid, and supplies it to heating or hot water.

Recently, the boiler is a method to lower the fuel consumption rate while increasing the combustion efficiency. Instead of supplying the air supply for fuel supply or combustion uniformly, the boiler is controlled by STEP control (low combustion, ) Or proportional control through PID (Proportional Integral Derivative) control is used.

Here, in the case of the STEP control, unnecessary energy consumption is prevented by supplying fuel and air through a predetermined step, but it is difficult to control accurately in accordance with the load variation.

In addition, the general PID control becomes frequent on / off of a combustor or a blower in a region where a load of heating or hot water is small, so that the combustion state becomes unstable and the amount of nitrogen oxide (NOx) There is a problem that the deviation becomes large and the durability of the components is deteriorated.

In recent years, there has been developed a boiler having a function of recirculating exhaust gas to re-supply exhaust gas to a burner and re-burn it in a combustion chamber in order to reduce nitrogen oxide emissions generated during combustion, Boilers have been developed that combine proportional control and exhaust gas recirculation (FGR) functions.

In this prior art, there is an inverter boiler which recirculates exhaust gas to an air blower through an exhaust gas recirculation passage to reduce nitrogen oxides while controlling an air blower to inverter control to reduce power consumption.

However, when the blower frequency is lowered in the low load region of the boiler, the blower RPM is lowered, so that the suction force capable of sucking the exhaust gas is lowered and the recirculation rate of the exhaust gas is lowered When the blower frequency is increased in the high load region, the suction force capable of sucking the exhaust gas increases as the blower RPM increases, the recirculation rate of the exhaust gas increases, and the amount of nitrogen oxides However, since the recirculation rate becomes excessively high, the burner flame becomes unstable, so that the amount of CO generated increases and noise is generated.

On the other hand, as a prior art of the present invention, there is a 'low nitrogen oxide inverter boiler' proposed in Korean Patent Publication No. 0838163.

As shown in FIG. 1, the prior art is provided with a combustion space in which a flame is burned, an exhaust gas discharge passage for discharging the burned gas, and a flame corresponding to a mixing ratio of the input fuel and combustion air to the combustion space And a boiler body (12) for heating the water filled therein by the flame of the combustion space to discharge the heated fluid; The exhaust gas recirculation passage is connected to the exhaust gas recirculation passage. The exhaust gas recirculation passage is connected to the exhaust gas recirculation passage. The exhaust gas recirculation passage is connected to the exhaust gas recirculation passage. An air blower 22 for blowing air; And a control unit for sensing the temperature / pressure of the fluid inside the boiler body and for providing a speed / deceleration driving signal proportional to the detected pressure / temperature of the fluid to the blower, A damper (27) for regulating the exhaust gas recirculation amount is installed in the connected exhaust gas recirculation passage.

The prior art is a technique of step control method in which exhaust gas is recirculated to an air blower through an exhaust gas recirculation passage to reduce power consumption by controlling an air blower while reducing nitrogen oxides.

In this prior art, incomplete combustion is performed by inverter control of the blower, and vibration and noise are frequently generated.

Korean Patent Publication No. 0838163

The present invention has been made in order to overcome the problems of the prior art as described above, and it is an object of the present invention to provide an exhaust gas recirculation apparatus and an exhaust gas recirculation method for recirculating exhaust gas generated in a combustion chamber to a blower, And the proportional control of the supply amount of the exhaust gas supplied from the recirculation flow path of the exhaust gas to the blower in accordance with the load of the boiler is continuously controlled in proportion to the load of the boiler and the proportional control boiler connected to the exhaust gas recirculation damper The purpose is to provide.

Further, according to the present invention, the opening degree of the air damper for controlling the flow rate of the combustion air and the opening degree of the FGR damper for controlling the recirculation flow rate of the exhaust gas are continuously controlled instead of stepwise, And to provide an interlocking proportional control boiler associated with an exhaust gas recirculation damper.

It is another object of the present invention to provide an interlocking proportional control boiler connected to an exhaust gas recirculation damper capable of smoothly supplying combustion air or exhaust gas by increasing the flow rate of air passing through a damper.

In order to accomplish the above object, the present invention provides an intermittently-operated proportional-control boiler connected to an exhaust gas recirculation damper of a boiler for heating a fluid by fire or heat, A combustion chamber providing heat; A water preheater for recovering waste heat of the exhaust gas while exhausting the exhaust gas burned in the combustion chamber to preheat the fluid; A blower for introducing the combustion air into the combustion chamber and supplying the combustion air to the combustion chamber; An air supply flow path connecting the blower and the combustion chamber and providing a path for moving the air for combustion; A blowing inlet flow path connected to a suction port of the blower to introduce outside air into the blower; An FGR flow path for mixing the exhaust gas discharged from the water supply preheater with the external air introduced into the blowing inlet flow path while communicating the water supply preheater and the blowing inlet flow path, and recirculating the exhaust gas; An air supply damper that is openably and closably provided in the air supply passage and adjusts the supply amount of the combustion air; An FGR damper installed in the FGR passage so as to be openable and closable to regulate a supply amount of the recirculating gas; And a PID control controller for controlling the opening degree of the air supply damper and the FGR damper, wherein the PID control controller monitors load fluctuations of the fluid and controls the supply damper and the FGR And the opening degree of the damper is continuously and proportionally controlled.

It is preferable that the PID control controller controls the opening degree of the air supply damper by an opening degree proportional to the load of the fluid and controls the opening degree of the FGR damper to an opening degree in inverse proportion to the opening degree of the air supply damper.

For example, the air supply damper and the FGR damper may include a damper main body that is openably and closably provided in the air supply flow path and the FGR flow path, respectively; And a damper motor for opening / closing the damper main body at a predetermined opening degree while being operated under the control of the PID control controller while being connected to the damper main body.

For example, the damper main body includes: a hinge shaft installed in the air supply passage and the FGR passage; And an opening / closing plate coupled to the hinge shaft in a manner corresponding to the air supply flow path and the FGR flow path, respectively, and opening / closing the air supply flow path and the FGR flow path while rotating around the hinge axis by operation of the damper motor And the like.

The damper main body is formed as an inclined surface on at least one side of both sides of the opening and closing plate so that the cross sectional area of the air supply duct and the FGR passage becomes narrower and narrower as the damper motor moves the air flow direction And a venturi slope surface for guiding the venturi slope.

For example, the opening / closing plate may be formed as a single body, and a central portion of the single body may be coupled to the hinge shaft and rotate about the hinge axis, and the venturi slope may be formed on at least one surface of the front surface or the rear surface of the opening / .

Alternatively, the opening / closing plate may be formed of a divided plate divided around the hinge axis, and the divided portions of the divided plates are coupled to the hinge axis so that the respective divided plates rotate in a symmetrical state about the hinge axis, The inclined surfaces may be formed symmetrically with respect to each other on one surface of each of the partition plates.

In addition, the FGR passage may be connected to the water preheater so that the end portion of the FGR passage extends in a direction corresponding to the discharge direction of the exhaust gas, and at the same time,

As described above, the interlocking proportional control boiler associated with the exhaust gas recirculation damper according to the present invention is operated in conjunction with the air supply for combustion so that the recirculation flow rate of the exhaust gas is continuously and proportionally controlled, The supply of air and the recycle gas is finely adjusted so that the combustion efficiency and the fuel consumption rate are improved and the emission amount of nitrogen oxide is minimized.

In particular, the present invention controls the opening degree of the FGR damper to an opening degree in inverse proportion to the air supply damper while controlling the opening degree of the air supply damper by the opening degree of the air supply damper in direct proportion to the load of the fluid, so that the opening degree of the FGR damper Since the recirculation ratio of the exhaust gas is kept constant, the nitrogen oxide can be stably reduced.

Further, since the present invention controls the flow rate of the combustion air through the air supply damper, frequent on-off of the blower and the combustor is reduced, so that vibration and noise can be reduced and durability of the component can be improved.

In the present invention, since the venturi slope is formed on the opening / closing plate constituting the damper main body, the flow rate of the air is increased as the cross-sectional area of the air supply flow path and the FGR flow path is narrowly reduced at the time of full opening, The combustion air can be supplied more smoothly and the exhaust gas can be smoothly recirculated even at a low load at which the FGR damper is fully opened.

1 is a schematic view showing a proportional control boiler according to the prior art;
FIG. 2 is a schematic view showing an interlocking proportional control boiler associated with an exhaust gas recirculation damper according to the present invention; FIG.
3 is a perspective view showing the configuration of the air supply damper and the FGR damper shown in Fig.
Fig. 4 is a longitudinal sectional view showing an embodiment of the opening and closing plate shown in Fig. 3; Fig.
Fig. 5 is a longitudinal sectional view showing another embodiment of the opening and closing plate shown in Fig. 3; Fig.
6 is a configuration diagram showing another embodiment of the FGR passage shown in Fig. 2. Fig.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted.

Embodiments in accordance with the concepts of the present invention can make various changes and have various forms, so that specific embodiments are illustrated in the drawings and described in detail in this specification or application. It is to be understood, however, that it is not intended to limit the embodiments according to the concepts of the present invention to the particular forms of disclosure, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between. Other expressions that describe the relationship between components, such as "between" and "between" or "neighboring to" and "directly adjacent to" should be interpreted as well.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises ", or" having ", or the like, specify that there is a stated feature, number, step, operation, , Steps, operations, components, parts, or combinations thereof, as a matter of principle.

2, the interlocked proportional control boiler connected to the exhaust gas recirculation damper according to an embodiment of the present invention includes a combustion chamber 100, a water preheater 200, a blower 300, an air supply passage 400, An air supply inflow passage 500, an FGR passage 600, an air supply damper 700, an FGR damper 800 and a PID controller 900. [

The combustion chamber 100 is a component that heats the fluid, such as water, by providing combustion by burning as the fuel is burned.

The combustion chamber 100 is formed in a tank shape as shown in FIG. 2 to provide a combustion space for the fuel, and a combustor 110 is provided therein to combust the fuel to provide a fire or heat.

Here, the fuel used in the combustion chamber 100 may be gas or oil, and alternatively, a fuel commonly used in the field to which the present invention belongs, such as wood or wood pellets, may be used.

The combustion chamber 100 is provided with a water pipe 120 through which the fluid flows on the outer circumferential surface. The combustion chamber 100 heats the fluid of the water pipe 120 through the heat and supplies the heated or heated water.

On the other hand, the fluid is supplied to the water pipe 120, heated by the heat of the combustion chamber 100, and then supplied to the use place after moisture is removed through the water separator 130.

The water preheater 200 preheats the water in the water tube 120 through the waste heat of the exhaust gas while constituting the discharge path of the exhaust gas burned in the combustion chamber 100.

2, the water preheater 200 is connected to the combustion chamber 100 through a waste heat recovery passage 140, which is a zigzag pipe between the combustion chamber 100 and the water pipe 120, The waste heat of the exhaust gas is recovered to improve the thermal efficiency, and the exhaust gas outlet temperature is lowered to raise the FGR effect. If the exhaust gas at a high temperature is recirculated, the nitrogen oxide reduction effect is reduced.

The blower 300 is operated under the control of a PID controller 900 to be described later to supply outside air to the combustion chamber 100.

The air supply passage 400 connects the discharge port 310 of the blower 300 and the combustion chamber 100 as shown in FIG. 2 and forms a path for air for combustion in the combustion chamber 100.

The air supply passage 400 is composed of a duct or a pipe and communicates the blower 300 with the combustion chamber 100.

The blowing inlet flow path 500 is a component for introducing outside air into the inlet port 320 of the blower 300 and is formed of a duct or a pipe and is connected to the inlet port 320.

Here, it is preferable that the air inlet / outlet flow path 500 is in thermal contact with the water pipe 120 while extending toward the water pipe 120 as shown in FIG.

Accordingly, the combustion efficiency of the combustion chamber 100 can be improved by supplying the external air introduced into the blower 300 through the blower inlet flow path 500 while being preheated by the water pipe 120, There is an advantage that noise can be reduced.

The FGR passage 600 is a component for flue gas recirculation and communicates with the water supply preheater 200 and the blowing air flow path 500 as shown in FIG. A part of the exhaust gas to be exhausted is supplied to the airflow inflow passage 500 and recirculated to reduce nitrogen oxides.

That is, the exhaust gas is exhausted to the water supply pre-heater 200, is supplied to the blowing air inflow passage 500 through the vacuum pressure of the blower 300 applied through the FGR passage 600, mixed with the external air, 400 to the combustion chamber 100 and re-burned.

At this time, exhaust gas is recovered while passing through the water supply preheater 200 and recycled through the FGR flow path 600 at a low temperature, so that the nitrogen oxide reduction effect can be improved.

6, the FGR passage 600 is connected to the water supply preheater 200, extends in a direction corresponding to the exhaust gas discharge direction, and is extended to the end of the FGR passage 600 to form a suction lance 610 .

That is, the FGR passage 600 recirculates a part of the exhaust gas discharged to the water supply pre-heater 200 through the suction lid 610 to the blower 300 smoothly.

As shown in FIG. 2, the air supply damper 700 is openably and closably provided in the air supply passage 400 to regulate the flow rate of the combustion air supplied to the combustion chamber 100.

The FGR damper 800 is openably and closably provided in the FGR passage 600 to regulate the flow rate of the exhaust gas supplied from the water supply preheater 200 to the blowing air flow path 500.

Here, specific embodiments of the FGR damper 800 and the air supply damper 700 will be described later.

The PID controller 900 is a component for controlling the opening degree of the air supply damper 700 and the FGR damper 800. The PID controller 900 may be provided on the control board of the boiler or may be remotely connected to the boiler in a server form.

The PID controller 900 monitors the load of the fluid heated by the combustion chamber 100, that is, the operating pressure and the temperature of the fluid, and controls the supply pressure of the fuel supplied to the combustion chamber proportionally. At the same time, the PID controller 900 controls the supply damper 700 ) And the opening degree of the FGR damper 800 are continuously controlled by proportional control.

That is, the PID controller 900 monitors the fluid load while measuring the temperature and pressure of the fluid through a pressure sensor or a temperature sensor (not shown) and controls the flow rate of the fuel in proportion to the measured load, And the flow rate of the recirculated gas supplied to the blower 300 is controlled in proportion to the flow rate of the combustion air.

Here, the PID controller 900 controls the air supply damper 700 with an opening degree proportional to the load of the fluid, and adjusts the FGR damper 800 with an opening degree in inverse proportion to the opening degree of the air supply damper 700.

For example, the PID controller 900,

When the load of the fluid is 20%, the opening degree of the air supply damper 700 is opened to 20% and the opening degree of the FGR damper 800 is 80%.

When the load of the fluid is 50%, the opening degree of the air supply damper 700 is 50%, and the opening degree of the FGR damper 800 is 50%.

When the load of the fluid is 100%, the opening degree of the air supply damper 700 is 80%, and the opening degree of the FGR damper 800 is 20%.

As described above, the PID controller 900 increases the opening degree of the FGR damper 800 to increase the recirculation rate of the exhaust gas, thereby reducing the nitrogen oxides. When the load is high, the PID controller 900 lowers the opening degree of the FGR damper 800, The exhaust gas recirculation rate of the exhaust gas is maintained to reduce the nitrogen oxide.

The air supply damper 700 and the FGR damper 800 may include a damper main body 710 and a damper motor 720 as shown in FIG.

The damper main body 710 is a constituent element that is openably and closably provided inside the air supply passage 400 and the FGR passage 600. More specifically, the damper main body 710 includes a hinge shaft 711 and an opening / closing plate 712 .

That is, the damper main body 710 includes a hinge shaft 711 for rotatably fixing the opening / closing plate 712 and the opening / closing plate 712, which form a valve body corresponding to the end face of the air supply passage 400 and the FGR passage 600 And opens and closes the air supply passage 400 and the FGR passage 600 through an opening / closing plate 712 which rotates around a hinge shaft 711.

3, the damper motor 720 is connected to the opening / closing plate 711 via the hinge shaft 712 and is operated by the PID controller 900 to rotate the opening / closing plate 711 to open the air supply duct 400 ) And the flow rate of the FGR flow passage 600 are controlled.

The damper motor 720 continuously and finely adjusts the opening degree of the air supply damper 700 and the FGR damper 800 while being operated under the control of the PID control controller 900 in accordance with the load of the fluid.

The opening / closing plate 712 may be formed as a single plate as shown in FIG. 4, and the center portion may be rotatably coupled through the hinge shaft 711. Alternatively, as shown in FIG. 5, 712a, and 712b, the divided portions are rotatably coupled through the hinge shaft 711, and the divided plates 712a and 712b are opened and closed while being rotated in a symmetrical state.

4 and 5, the damper main body 710 may further include a venturi slope 715 formed in the opening / closing plate 712. [

The venturi slope 715 is a component for increasing the flow velocity by providing a venturi effect to the air passing through the damper main body 710. [

The venturi tube is based on Bernoulli's theorem. As the diameter of the venturi decreases, the pressure of the fluid decreases and the flow rate increases.

The venturi inclined surface 715 is formed in an inclined surface forming an identical body on the surface of the opening and closing plate 712 so that the sectional area of the air supply passage 400 and the FGR passage 600 when the opening and closing plate 712 is opened is narrowed .

4, the venturi slope 715 may be provided on one side or both sides of the opening / closing plate 712 when the opening / closing plate 712 is formed as a single plate, The cross-sectional area of the air passage 600 is gradually reduced in the air moving direction.

Accordingly, the combustion air of the air supply flow passage 400 and the recirculation gas of the FGR flow passage 600 pass through the opening / closing plate 712, and the flow velocity increases as the cross-sectional area of the flow passage is gradually narrowed by the venturi slope 715.

5, when the opening / closing plate 712 is constituted by a partition plate, the venturi slope 715 is provided symmetrically on one surface of each of the partition plates 712a and 712b to reduce the flow path .

According to the interlocking proportional control boiler connected to the exhaust gas recirculation damper according to the present invention, as the recirculation flow rate of the exhaust gas is continuously controlled in association with the combustion air supply, The PID controller 900 controls the opening degree of the air supply damper 700 so that the amount of the nitrogen oxide discharged from the fluid supply port is reduced. The opening degree of the FGR damper 800 is controlled to an opening degree that is inversely proportional to the air supply damper 700 while controlling the degree of opening of the FGR damper 800 so that the recirculation rate of the exhaust gas is reduced to a constant So that the nitrogen oxide can be stably reduced.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be apparent to those skilled in the art that various changes, substitutions, and alterations can be made therein without departing from the spirit of the invention.

100: combustion chamber 110: combustor
120: water tube 130: water separator
140: waste heat recovery furnace 200: water preheater
300: blower 310: outlet
320: inlet port 400:
500: air inlet inflow channel 600: FGR air channel
700: Supply damper
710: damper main body 711: hinge shaft
712: Opening / closing plates 712a, 712b:
715: Venturi slope
720: Damper motor
800: FGR damper 900: PID control controller

Claims (8)

In a boiler for heating fluid by fire or heat,
A combustion chamber for providing flame and heat with combustion of the fuel by the combustor;
A water preheater for recovering waste heat of the exhaust gas while exhausting the exhaust gas burned in the combustion chamber to preheat the fluid;
A blower for introducing the combustion air into the combustion chamber and supplying the combustion air to the combustion chamber;
An air supply flow path connecting the blower and the combustion chamber and providing a path for moving the air for combustion;
A blowing inlet flow path connected to a suction port of the blower to introduce outside air into the blower;
An FGR flow path for mixing the exhaust gas discharged from the water supply preheater with the external air introduced into the blowing inlet flow path while communicating the water supply pre-heater and the blowing inlet flow path, and recirculating the exhaust gas;
An air supply damper that is openably and closably provided in the air supply passage and adjusts the supply amount of the combustion air;
An FGR damper installed in the FGR passage so as to be openable and closable to regulate a supply amount of the recycle gas; And
And a PID control controller for controlling the opening of the air supply damper and the FGR damper,
The PID control controller includes:
Monitoring the load variation of the fluid to continuously control the opening degree of the air supply damper and the FGR damper while proportionally controlling the supply pressure of the fuel,
Wherein the air supply damper and the FGR damper comprise:
A damper main body provided in the air supply passage and the FGR passage so as to be openable and closable, respectively; And
And a damper motor which is connected to the damper main body and opens and closes the damper main body by a predetermined opening degree under the control of the PID control controller,
In the damper main body,
A hinge shaft installed in the air supply passage and the FGR passage; And
And an opening / closing plate coupled to the hinge shaft in a form corresponding to the air supply flow path and the FGR flow path and opening / closing the air supply flow path and the FGR flow path while rotating around the hinge axis by the operation of the damper motor and,
And a venturi slope surface formed on each of both side surfaces of the opening / closing plate so as to narrow the sectional area of the air supply passage and the FGR passage narrowly in the moving direction of the air when the opening / closing plate is opened by the damper motor Wherein the exhaust gas recirculation damper is connected to the exhaust gas recirculation damper.
The method according to claim 1,
The PID control controller includes:
The opening degree of the air supply damper is controlled to an opening degree proportional to the load of the fluid,
And the opening degree of the FGR damper is controlled to an opening degree in inverse proportion to the opening degree of the air supply damper.
delete delete delete The method according to claim 1,
The open /
Wherein a central portion of the monolith is coupled to the hinge axis and rotates about the hinge axis,
The venturi slope may be formed,
Wherein the exhaust gas recirculation damper is formed on both side surfaces of the open / close plate.
The method according to claim 1,
The open /
Wherein each of the divided plates is coupled to the hinge axis so that each of the divided plates is rotated in a symmetrical state about the hinge axis,
The venturi slope may be formed,
Wherein the partition plate is formed symmetrically with respect to one side of each of the partition plates, and is connected to the exhaust gas recirculation damper.
The method according to claim 1,
The FGR passage
Wherein the exhaust gas recirculation damper is connected to the water supply preheater and has an end extending in a direction corresponding to a discharge direction of the exhaust gas and having a suction lid extended in an end portion thereof.

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