KR20210067511A - Method for Combustion Control for Combustion Area Improve of Boiler - Google Patents

Abstract

The present invention relates to a combustion control method for improving the combustion range of a boiler, and aims to improve usability and avoid unnecessary gas use by preventing, when driving a boiler, conditions where the temperature becomes higher than a set temperature or combustion and extinguishment are repeated in the case of heating with a small load or using a small amount of hot water since the minimum heat capacity allowed for heat capacity control is high. The combustion control method includes a first process of starting ignition and combustion by limiting the minimum heat capacity to a first-stage minimum heat capacity; a second process of calculating a combustion stabilization time; a third process of gradually decreasing the minimum heat capacity when the combustion stabilization time has elapsed; and a fourth process of limiting the minimum heat capacity to a second-stage minimum heat capacity.

Description

{Method for Combustion Control for Combustion Area Improve of Boiler}

The present invention relates to a combustion control method for improving the combustion range of a boiler to improve the combustion range by limiting the minimum amount of heat during combustion of the boiler in stages.

There is a limit to the minimum amount of heat that can be stably set in consideration of the characteristics of combustion-related parts and the external environment during boiler operation.

In order to lower the minimum amount of heat while the maximum amount of heat is fixed, it is possible to stably lower the minimum heat by adding a burner with a low minimum heat or by adding parts that can control the gas and air ratio, but there are problems of stability and cost increase due to the addition of parts. have.

1 is a cross-sectional configuration diagram of a dual venturi for a combustion device according to the prior art, which is disclosed in Korean Patent Registration No. 10-1448992 (October 13, 2014). Referring to this, a mixture of air and gas to be supplied to a burner In order for gas to be introduced into the turbofan, a housing having a discharge unit 300 formed therein is provided, and an air supply unit and a gas supply unit are formed. The air supply unit is partitioned by the first partition wall 130 to provide first air The supply unit 110 and the second air supply unit 120 are formed separately.

The gas supply unit is partitioned by a second partition wall 230 , the first gas supply unit 210 having a first opening to communicate with the first air supply unit 110 , and the second air supply unit 120 , The second opening 221 is formed separately to be communicated with the second gas supply unit 220 .

Meanwhile, an opening/closing means for simultaneously opening and closing the second air supply unit 120 and the second gas supply unit 220 is provided in the middle of the housing.

The opening/closing means includes a motor 410 provided on the outside of the housing, a damper 420 having two or more concave and convex guides formed on the inner wall and coupled to the motor 410 , and the concave and convex guides. A movable body 440 composed of a concave guide and a convex guide so as to be tooth-engaged in correspondence with the guide, and coupled to the center of the movable body 440 to open and close the second opening 221 by the movement of the movable body 440 It is composed of a valve body 430 .

As described above, according to the conventional dual venturi for a combustion device, first, it is possible to control the amount of high heat and low heat required in the combustion device, so that it is possible to reduce the fuel cost.

However, since the conventional dual venturi for combustion equipment has a limit in the minimum amount of heat that can be stably set for boiler combustion-related parts, in order to lower the minimum amount of heat while the maximum heat is fixed, a composite design of a burner with a low minimum heat or gas and air ratio It is possible to stably lower the minimum amount of heat by adding parts that can be adjusted, but there are problems in stability and cost increase due to the addition of parts.

Domestic Patent Registration No. 10-1448992 (Announcement Date: 2014.10.13.)

Therefore, in order to improve the problems of the prior art, the present invention improves usability by preventing a condition in which the minimum amount of heat that can be controlled when a boiler is driven is higher than the set temperature when heating with a small load or when using a small amount of hot water or repeated combustion and fire extinguishing conditions. An object of the present invention is to provide a combustion control method for improving the combustion range of a boiler to improve and prevent unnecessary gas use.

In the combustion control method for improving the combustion range of a boiler to widen the combustion range by adjusting the steps of the minimum heat amount and the maximum heat amount set by the control unit that senses the state of the boiler for achieving the object of the present invention, the control unit is the boiler a first process of starting ignition and combustion by limiting the first-stage minimum amount of heat during initial ignition according to the ignition requirement of a second process of calculating the combustion stabilization time at the time of rising to a set combustion stabilization temperature by detecting the component temperature of the boiler; a third process of gradually decreasing the minimum calorie according to the minimum calorie decrease in steps during the set minimum calorie reduction time when the combustion stabilization time elapses in the second process; and a fourth process of limiting the minimum calorie to a preset minimum calorie in the second stage when the minimum calorie reduction time in the third process elapses.

Here, the first and second steps are the minimum amount of heat required for the burner of the boiler to burn stably and are set according to the capacity of the burner, and the maximum amount of heat is the maximum amount of heat that the burner of the boiler can burn. It is set according to, and the first-stage minimum calorie is characterized in that it is higher than the second-stage minimum calorie.

In addition, the calorie control range of the first process is limited to the minimum calorie to the maximum calorie in the first step, and the calorie control range of the fourth process is limited to the minimum calorie to the maximum calorie in the second stage, so that the calorie control range for combustion is expanded characterized in that

In addition, in addition to the fourth process, the step of determining whether or not a preset fire-extinguishing waiting time has elapsed when re-ignition is detected after being extinguished during the second-step minimum calorie limit combustion; determining that the fire extinguishing standby time has elapsed and returning to the first process; and if the fire-extinguishing waiting time has not elapsed, combustion is limited to the minimum calorie in the second stage; characterized in that it consists of.

The combustion control method for improving the combustion range of a boiler according to the present invention is effective in improving usability because stable combustion is possible under a small heating load or low-temperature hot water flow rate when the boiler is driven. It has the effect of preventing use, and since the minimum calorie is stably lowered in stages, it is not necessary to provide a complex design of a burner with a low minimum calorie or additional parts for regulating the gas and air ratio in order to lower the minimum calorie. It works.

1 is a configuration diagram of a dual venturi for a combustion device according to the prior art;
2 is a block diagram of a combustion control device of a boiler for implementing the present invention;
3 is a flowchart of a combustion control process for improving the combustion range of a boiler according to an embodiment of the present invention;
4 is a graph showing a change in air ratio over time after combustion according to an embodiment of the present invention;
5 is a graph display for explaining the calculation of the minimum calorie stabilization time,
6 is a graph display for explaining the relationship between the amount of air and the amount of heat;
7 is a graph display for explaining the calculation of the calorific value reduction according to time and the expansion of the combustion range.

The features and effects of the present invention described above will become more apparent through the following detailed description in relation to the accompanying drawings, and accordingly, those of ordinary skill in the art to which the present invention pertains can easily implement the technical idea of the present invention. will be able

Since the present invention may have various changes and may have various forms, specific embodiments will be illustrated and described in detail in the text.

However, this is not intended to limit the present invention to the specific disclosed form, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention.

The features and effects of the present invention described above will become more apparent through the following detailed description in relation to the accompanying drawings, and accordingly, those of ordinary skill in the art to which the present invention pertains can easily implement the technical idea of the present invention. will be able

A combustion control method for improving the combustion range of a boiler according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram of a boiler combustion control device for implementing the present invention, and a supply temperature detection unit 11 for detecting the temperature of combustion-related parts of the boiler, a flame detection unit 12 for detecting a flame of a burner, Combustion is started according to the boiler operation of the temperature controller 40, the minimum amount of heat in the set stage is limited according to the temperature collected from the supply temperature detection unit 11, and combustion is performed, and when the combustion stabilization time elapses, the calculated minimum amount of heat is reduced. After gradually decreasing the minimum amount of heat during the minimum heat amount reduction time, the control unit 20 for burning by limiting the minimum amount of heat to the set two-step minimum amount of heat, and a fan driving unit for driving as the boiler is burned by the control of the control unit 20 ( 31), a gas supply unit 32 and a burner 33.

Here, the supply temperature detection unit 11 preferably directly detects the temperature of the combustion-related parts such as the burner 33 or the gas supply device, or by detecting the outlet temperature at which the supply water is heated and supplied as heating water or hot water, the control unit (20) is configured to be approved.

The control unit 20 calculates the combustion stabilization time, the minimum amount of heat reduction, etc., the calculation unit 21, the calculated value of the calculation unit 21, the first and second steps minimum heat amount, the maximum heat amount, the minimum heat amount reduction time, etc. It is stored in the memory unit 22 for storing.

3 is a flowchart of a combustion control process for improving the combustion range of a boiler according to an embodiment of the present invention, wherein the control unit 20 detects a combustion request by operation of the temperature controller 40 while the boiler is waiting for combustion. The fan driving unit 31 , the gas supply unit 32 , the burner 33 , the flame detection unit 12 , and the like are driven to start combustion.

At this time, if the ignition condition is the initial ignition, combustion is controlled by limiting the minimum amount of heat to the minimum heat amount of the first stage, and if the extinguishing standby time has not elapsed, the minimum heat amount is limited to the minimum heat amount of the second step and combustion starts.

On the other hand, the minimum amount of heat is the minimum amount of heat required for the burner of the boiler to burn stably and is set according to the capacity of the burner, and the maximum amount of heat is the maximum amount of heat that the burner of the boiler can combust is set according to the capacity of the burner, The first-stage minimum calorie is set to be higher than the second-stage minimum calorie and is stored in the memory unit 22 .

Here, the lower the minimum amount of heat of the boiler is, the more advantageous it is for low-load heating and control at a low temperature, and it is possible to control a low hot water flow rate and a low set temperature when using hot water.

However, there is a limit to the minimum amount of heat that can stably set the combustion state for boiler combustion-related parts, so in order to lower the minimum amount of heat while the maximum heat is fixed, a composite design of a burner with a low minimum heat or parts that can control the gas and air ratio should be used. Although it is possible to stably lower the minimum amount of heat by adding it, there are problems in stability and cost increase due to the addition of parts.

Considering the characteristics of combustion-related parts and the external environment, there is a limit to the minimum amount of heat that can be set stably. For example, combustion-related parts such as gas supply devices and burners have a lot of characteristics change depending on the temperature, so there is a difference in the ratio of gas and air in the cold state and the hot state, and combustion in the cold state has a large amount of air or a large amount of gas. This is small, so the air/gas ratio (excess air ratio: λ) is high. Conversely, in a hot state, combustion has a low air/gas ratio (excess air ratio: λ) due to a small amount of air or a large amount of gas.

Referring to FIG. 4 , when the boiler is initially ignited, combustion-related parts are in a cold state, so when combustion is carried out in a state with a high air excess rate (λ = air amount/gas amount), abnormal noise and unsafe combustion are highly likely, In combustion, the minimum calorific value is limited to the first stage minimum calorific value, and after combustion, the temperature of the combustion parts rises and becomes saturated and the minimum calorific value is gradually lowered from the point when the combustion is stabilized, thereby expanding the range where the calorific value for combustion can be controlled. Combustion should be carried out in a stable state.

That is, after the initial ignition of the boiler, the control unit 20 continuously detects the temperature from the supply temperature detection unit 11, calculates the combustion stabilization time at the time when the combustion is stabilized, and the calculated combustion stabilization time does not elapse. If not, calculate the stabilization time and repeat the stabilization time elapsed check

Referring to FIG. 5 , since the stabilization time has an effect on combustion stabilization depending on the degree of preheating of the burner, the time is changed according to the current control heat amount to calculate the stabilization time as the minimum time if the control heat amount is the maximum amount of heat, and if the initial minimum amount The stabilization time is calculated as the maximum time, and the combustion stabilization time is changed according to the amount of control heat.

When the stabilization time elapses, abnormal combustion does not occur even when the minimum amount of heat is reduced. However, if the minimum amount of heat is rapidly reduced, instability of temperature control or combustion instability due to a change in air/gas ratio may occur, so the minimum heat amount reduction time Until this elapses, the limit change is repeatedly performed with the calculated minimum calorie reduction amount.

Here, the minimum heat amount reduction time is set according to the burner capacity of the boiler and stored in the memory unit 22 in order to prevent a rapid reduction of the minimum heat amount.

In addition, the calculation of the minimum amount of heat reduction is calculated by the calculation unit 21 through Equation 1 below.

When the minimum calorie reduction time has elapsed, the control unit 20 controls the calorie by limiting the minimum calorie to the minimum calorie 2, and extinguishes the fire when the extinguishing condition is satisfied.

6 and 7, in the initial ignition state, the minimum calorie for combustion starts combustion with the first-stage minimum calorie, and after the combustion stabilization time, it decreases to the second-stage minimum calorie to limit combustion. The combustion control range when burning with the minimum calorie in the first stage can control combustion between the minimum calorie and the maximum calorie in the first stage. However, when the combustion is restricted to the minimum calorie in the second stage, the calorific value control range from the minimum calorie to the maximum calorie in the second stage combustion control becomes possible.

That is, the combustion control range can be improved by expanding the calorific value control range for combustion from the minimum calorific value of the first stage to the minimum caloric value of the second stage.

On the other hand, if the combustion stabilization time has not elapsed or if re-ignition is detected after extinguishing in a state in which the minimum calorie reduction time has not elapsed, the controller 20 determines the initial ignition as the initial ignition and sets the control range of the minimum calorie to 1 Step Return to the process of setting limits to the minimum calorie.

When ignition is made after the control range of the minimum amount of heat is burned while being burned with the minimum amount of heat in the second stage, the control unit 20 determines that the ignition is re-ignited and limits the combustion range of the minimum amount of heat in the second step.

In addition, when the temperature of the combustion-related parts is cold below the set temperature, the boiler determines the initial ignition and requires the combustion stabilization time. However, in re-ignition that is used again within a short time after extinguishing, the temperature of the combustion-related parts is higher than the set temperature. Since it maintains a saturated state, abnormal combustion does not occur even if it is limited to the minimum calorie in the second stage immediately after re-ignition.

Therefore, after the combustion, it is checked whether the ignition condition is the initial ignition, and if it is the initial ignition, the combustion range is limited to the minimum amount of heat in the first stage, and if it is determined as re-ignition rather than the initial ignition, whether the temperature of the combustion-related parts is in a saturated state above the set temperature It is determined whether the elapsed time after fire extinguishing to confirm is within the set fire extinguishing waiting time.

If the extinguishing standby time has elapsed, the operation is performed as in the initial ignition state, and if the extinguishing standby time has not elapsed, the minimum calorie is immediately limited to the second-stage minimum calorie to control the calorie.

Here, the fire-extinguishing standby time has an effect on stabilization according to the degree of preheating of the combustion parts, particularly the burner, and since the burner is kept warm by the temperature of the heat exchanger, it is affected by the temperature of the heat exchanger.

Therefore, when the temperature of the water at the outlet of the heat exchanger detected by the supply temperature detector 11 during fire extinguishing is high, the fire extinguishing standby time is calculated as the maximum time, and when the water temperature is low, the fire extinguishing standby time is calculated and determined as the minimum time.

As described above, although the combustion control method for improving the combustion range of a boiler according to an embodiment of the present invention has been described with reference to the limited embodiments and drawings, it is not limited by this embodiment, and is common in the technical field to which the present invention pertains. Of course, various modifications and variations are possible within the scope of the technical spirit of the present invention and the scope of the claims to be described below by those skilled in the art.

11: supply temperature detection unit 12: flame detection unit
20: control unit 21: arithmetic unit
22: memory unit 31: fan driving unit
32: gas supply unit 33: burner
40: temperature controller

Claims (10)

In the combustion control method for improving the combustion range of the boiler, the combustion range is widened by adjusting the steps of the minimum and maximum heat amount set by the control unit that senses the state of the boiler,
a first process of starting ignition and combustion by limiting the control unit to the minimum amount of heat in the first stage during initial ignition according to the ignition request of the boiler;
a second process of calculating the combustion stabilization time at the time of rising to a set combustion stabilization temperature by detecting the component temperature of the boiler;
a third process of gradually decreasing the minimum calorific value according to the minimum caloric reduction amount step by step during the set minimum caloric reduction time when the combustion stabilization time has elapsed in the second process; and
A combustion control method for improving the combustion range of a boiler, comprising: a fourth process of limiting the minimum amount of heat to a preset minimum heat amount of the second step when the minimum heat amount reduction time has elapsed in the third step. According to claim 1,
The minimum amount of heat in the first and second steps is the minimum amount of heat required for the burner of the boiler to burn stably, and is set according to the capacity of the burner,
The maximum amount of heat is the maximum amount of heat that the burner of the boiler can burn, and is set according to the capacity of the burner,
The combustion control method for improving the combustion range of the boiler, characterized in that the first-stage minimum calorie is higher than the second-stage minimum calorie. 3. The method of claim 2,
The calorific value control range of the first process is limited to the first step minimum calorific value to the maximum calorific value,
The combustion control method for improving the combustion range of a boiler, characterized in that the heat amount control range of the fourth process is limited to the minimum heat amount to the maximum heat amount in the second stage, so that the heat amount control range for combustion is expanded. According to claim 1,
The combustion control method for improving the combustion range of the boiler, characterized in that the temperature of the parts of the boiler in the second process is the temperature of the gas supply device or the burner, or the hot water outlet temperature of the boiler. According to claim 1,
In the second process, the combustion stabilization time is a time at which the excess air ratio (air/gas ratio) is lowered as the temperature of the parts of the boiler rises from the initial low-temperature state to the high-temperature state, and combustion of a boiler, characterized in that it starts to burn in a stable state Combustion control method to improve range. According to claim 1,
In the second process, the combustion stabilization time changes the combustion stabilization time according to the current control heat quantity,
If the control heat amount is the maximum amount of heat, the stabilization time is calculated as the minimum time,
A combustion control method for improving the combustion range of a boiler, characterized in that the stabilization time is calculated as the maximum time if the initial minimum heat amount. According to claim 1,
The combustion control method for improving the combustion range of a boiler, characterized in that the minimum amount of heat reduction in the third process is calculated by the following equation.
[Equation]

8. The method of claim 1 or 7,
The combustion control method for improving the combustion range of a boiler, characterized in that the minimum calorie reduction time in the third process and the fourth process is set according to the burner capacity of the boiler in order to prevent a rapid decrease in the minimum calorie. According to claim 1,
In the third process, if the combustion stabilization time has not elapsed, or if re-ignition is detected after extinguishing in a state in which the minimum calorie reduction time has not elapsed in the fourth process, the control unit determines that the ignition is the initial ignition and controls the minimum calorie. A combustion control method for improving the combustion range of a boiler, characterized in that returning to the process of limiting the range to the first-step minimum calorie setting. According to claim 1,
determining whether a preset fire-extinguishing waiting time has elapsed when re-ignition is detected after being extinguished during the second-step minimum calorie limit combustion in addition to the fourth process;
determining that the fire extinguishing standby time has elapsed and returning to the first process; and
Combustion control method for improving the combustion range of a boiler, characterized in that consisting of; when the waiting time for fire extinguishing has not elapsed, the second step of limiting the combustion to the minimum amount of heat.

Images