JP3495995B2 - Burner combustion control method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a burner combustion control method applied to a regenerative burner or the like.

[0002]

2. Description of the Related Art Conventionally, in equipment such as a heating furnace, as shown in FIG. 4, the temperature inside the heating furnace 1 is measured by a temperature sensor Tx, and this measured value is input to a temperature adjusting device 2, The temperature deviation is calculated by comparing the measured value with the preset furnace temperature previously input to the temperature control device 2, and the measured value and the temperature deviation of the in-furnace temperature are input to the burner control device 3 to burner control device. The combustion amount of the burner 4 corresponding to the in-furnace temperature and the temperature deviation is determined from the combustion amount pattern preset to 3, and the supply amount (flow rate) of the fuel supplied to the burner 4 to match the combustion amount. And the supply amount (flow rate) of the combustion air are controlled while the air ratio is kept at a preset value (for example, μ = 1.15) by using the composite throttle control.

It should be noted that several patterns are preset for the combustion amount pattern depending on the material to be treated and the like, and the optimum pattern is selected from them. Also,
The air ratio is set in advance depending on whether the inside of the furnace is controlled to an oxidizing atmosphere or a reducing atmosphere, and the optimum pattern is selected from the patterns.

Next, a control method of the composite throttle control executed by the burner control device 3 will be described. The combined throttle control is performed by using the relationship between the flow coefficient N of the burner when the burner 4 is a fixed throttle, the flow rate Q of the fluid, and the supply pressure P ₂ before the burner (equation (3)), and setting the flow control valve 5 to the variable throttle. And the flow rate Q of the flow rate adjusting valve, the flow rate Q of the fluid, and the differential pressure P ₁ at the flow rate adjusting valve 5 (equation (2)), and the supply pressure P ₀ on the primary side of the flow rate adjusting valve 5. And the relationship between the differential pressure P ₁ at the flow control valve 5 and the supply pressure P ₂ before the burner (Equation (1))
From the flow rate Q, the flow rate coefficient V of the flow rate adjusting valve 5, and the burner 4
The relationship (equation (1a)) between the flow coefficient N of the flow rate N and the supply pressure P ₀ on the primary side of the flow rate adjusting valve 5 is determined.

[0005]

[Equation 3]

When the above equation (1a) is expanded with respect to the flow coefficient V of the flow rate adjusting valve 5, the flow rate coefficient V of the flow rate adjusting valve 5 is the flow rate Q and the flow coefficient of the burner 4 as shown in the following equation (4). It is represented by the relationship between N and the supply pressure P ₀ .

[0007]

[Equation 4]

Here, the characteristics of the flow rate adjusting valve 5 to be used are grasped by measuring the relationship between the valve opening degree S'of the flow rate adjusting valve 5 and the flow rate coefficient V'in advance. Further, the flow rate coefficient N of the burner 4 for a certain flow rate (for example, the flow rate at the time of maximum combustion of the burner 4) is also actually measured to grasp its characteristics.

By the way, the supply state of the fluid in front of the burner 4 is stable (the temperature and pressure of the fluid do not fluctuate).
In this case, the flow coefficient N of the burner 4 can be treated as a fixed value.

For example, the burner has a turndown ratio of 10:
Looking at the burner No. 1 (the burner whose combustion amount can be reduced to 1/10 of the maximum combustion amount), when the numerical value of Table 1 shown below is substituted into the formula (3), the flow coefficient N of the burner 4 is calculated. , At maximum combustion, flow coefficient Nmax = 5.774
On the other hand, the flow coefficient Nmin = 4.
It becomes 472.

[0011] Next, when the equation (4) by substituting the flow coefficient N of the burner 4 as determined by the numerical and the calculation in Table 1 determine the flow coefficient V of the flow control valve 5, Vmin ₁ at the time of minimum firing
= 0.5O3. On the other hand, when the flow rate coefficient Vmin at the time of minimum combustion is calculated, the flow rate coefficient at the time of minimum combustion is calculated as Vmin ₂ = 0.502 when the flow rate coefficient at the time of maximum combustion Nmax = 5.774 is calculated. The flow coefficient Nmi
The error with respect to the flow coefficient Vmin ₁ obtained by applying n is 0.
It is only 2%, which shows that there is no problem in control.

[0012]

[Table 1]

Therefore, there is no problem even if the above-mentioned measured value is used as the flow coefficient N of the burner 4, and the flow coefficient of the flow control valve 5 at the time of measurement can be obtained only by measuring the supply pressure P ₀ on the primary side of the flow control valve 5. Since V can be calculated, the valve opening S can be unitarily determined from this calculated value. (The flow rate Q is determined from the combustion amount preset from the furnace temperature and temperature deviation as described above.)

That is, when it is necessary to change the flow rate according to the change of the combustion amount, the fuel supply amount (flow rate) is determined in advance for the change amount of the combustion amount, and the required air amount for the fuel flow rate is changed. The amount can also be calculated from the air ratio. At this time,
Since the flow coefficient N of the burner 4 is known as an actual measurement value, the valve opening degree S of the flow rate adjusting valve 5 required for the flow rate Q, that is, only by actually measuring the supply pressure P ₀ on the primary side of the flow rate adjusting valve 5, that is, The flow coefficient V of the flow control valve 5 can be calculated. On the other hand, since the valve opening of the current flow rate adjusting valve 5 can be actually measured, the flow rate coefficient V'is uniquely determined from the actually measured valve opening S ', and the flow rate coefficient V obtained by the above calculation and the actually measured flow rate adjustment. Valve 5
The valve opening degree S'of the flow rate adjusting valve 5 is adjusted so that the deviation becomes zero.

In this case, the relationship between the flow rate coefficient V and the valve opening degree S thereof does not necessarily have to be a function (mathematical expression), and is stored in the burner controller 3 in the form of, for example, a table. Is also good. Further, since the flow rate set value set in the burner control device 3 is a value in the standard state, if the temperature T of the fluid is measured and the temperature is corrected as shown in FIG. 4, the control accuracy is further improved. To do. Further, by providing a pressure sensor in front of the burner so that the supply pressure P ₂ before the burner can be measured, it becomes possible to detect a failure of the burner itself such as nozzle blockage.

[0016]

By the way, if the composite throttle control is used, as will be apparent from the above description, the flow control valve (variable throttle means) 5 and the burner (fixed throttle means) 4 provided in the pipe are connected. Measure the flow coefficient beforehand and burner 4
The flow rate coefficient V of the flow rate adjusting valve 5 can be uniquely determined only by measuring the supply pressure P ₀ on the primary side of the flow rate adjusting valve 5 by setting the flow rate coefficient N to a fixed value.

That is, in the conventional composite throttle control, it is an essential condition that the flow coefficient N of the burner 4 be a fixed value, that is, that the state of the supplied fluid (temperature, pressure, etc.) is stable before the burner. Therefore, when the state before the burner is stable, the supply amount of the fluid can be accurately controlled while keeping the air ratio constant.

However, in recent years, in a heating furnace or the like, a regenerative burner (hereinafter, referred to as
Regeneration burner) has come into use.

Since the regenerative burner recovers the amount of heat of the exhaust gas in the furnace by the heat storage body and preheats the combustion air with the recovered heat and then supplies the burner air to the burner, until the temperature in the furnace stabilizes. The volume of the supply fluid changes due to the temperature change of the exhaust gas passing through the heat storage body (normal temperature when the furnace is started up, for example, about 1100 ° C. during steady operation of the heating furnace), which changes the supply pressure P ₂ before the burner. Therefore, in the actual equipment, the flow coefficient N of the burner (fixed throttle means) changes from moment to moment, whereas in the conventional combined throttle control, the flow coefficient N is set to a fixed value, so that the flow coefficient according to the change in the state of the fluid. There was a problem that it was not possible to calculate using N.

For example, when the flow coefficient N of the burner is controlled to be a fixed value regardless of the temperature change of the preheated air in the temperature rising process of the furnace using the above-mentioned regenerative burner, at the start of operation and the completion of temperature rise, As shown in Table 2, the pre-burner pressure of the combustion air changes from 3.0 kPa to 5.0 kPa, and when converted into an air ratio, an error of about 0.2 occurs. For this reason, there is a problem that the air ratio cannot be kept constant throughout the operation of the furnace.

[0021]

[Table 2]

In view of the above conventional problems, the present invention provides a burner control method for performing combined throttle control, in which the flow coefficient of the burner is determined by actually measuring the pressure and valve opening to determine the actual flow coefficient of the burner. The purpose is to be able to handle the measured value according to the change of the fluid state.

[0023]

To achieve the above object, the first aspect of the present invention provides a burner flow coefficient N preset as a fixed value and a fuel preset for the burner combustion amount. The flow rate and the flow rate of the combustion air obtained from this fuel flow rate and a preset air ratio, and the supply pressure P ₀ of the fluid on the primary side of the flow rate adjusting valve provided in the fuel supply system and the combustion air supply system. The measured value of the supply pressure P ₀ is applied to the following equation (A) indicating the relationship to calculate the flow coefficient V of the flow rate adjusting valves provided in the fuel supply system and the combustion air supply system, and The relationship between the valve opening degree S ′ of the flow rate adjusting valve and the flow rate coefficient V ′ is actually measured, the measured flow rate coefficient V ′ is compared with the flow rate coefficient V obtained by the above calculation, and a deviation is obtained. The valve opening can be adjusted so that In the combustion control method of the burner for controlling the leaving combustion rate maintaining the air ratio constant, the feed pressure P ₂ and the fluid of the fluid at the front burner in the case of the fixed throttle burner flow rate Q and the burner of the flow coefficient N
And the relationship between the differential pressure P ₀ -P ₂ of the fluid in the flow rate adjusting valve when the flow rate adjusting valve is a variable throttle, the flow rate Q of the fluid, and the flow rate coefficient V of the flow rate adjusting valve. Equation (B) is obtained from the measured value of the supply pressure P ₀ on the primary side of the flow rate control valve, the measured value of the supply pressure P ₂ before the burner, and the measured valve opening S ′ of the flow rate control valve. The actual flow coefficient N'of the burner is obtained by applying the flow coefficient V'of the flow control valve, and this actual flow coefficient N'is applied instead of the flow coefficient N of the burner in the above formula (A) to obtain the flow rate of the burner. The present invention provides a burner combustion control method characterized in that a coefficient is set to a variation value according to a fluid state.

[0024]

[Equation 5]

In the second aspect of the invention, the burner flow coefficient N set as a fixed value in advance, the fuel flow rate set in advance with respect to the combustion amount of the burner, and the fuel flow rate and the preset air ratio are set. The following equation (A) showing the relationship between the flow rate of the combustion air obtained from the above and the supply pressure P ₀ of the fluid on the primary side of the flow rate adjusting valve provided in the fuel supply system and the combustion air supply system The measured value of the pressure P ₀ is applied to calculate the flow rate coefficient V of the flow rate adjusting valves provided in the fuel supply system and the combustion air supply system, and the valve opening degree S ′ and the flow rate coefficient of the flow rate adjusting valve are calculated in advance. The relationship with V ′ is actually measured, the measured flow coefficient V ′ is compared with the flow coefficient V calculated by the above calculation to obtain a deviation, and the valve opening is adjusted so that the deviation becomes zero. Burner combustion control method and fixed throttle Flow rate Q and burner flow coefficient N of the supply pressure P ₂ and the fluid of the fluid at the front burner in the case of the
And the relationship between the differential pressure P ₀ -P ₂ of the fluid in the flow rate adjusting valve when the flow rate adjusting valve is a variable throttle, the flow rate Q of the fluid, and the flow rate coefficient V of the flow rate adjusting valve. In equation (B), the measured value of the supply pressure P ₀ on the primary side of the flow rate control valve, the measured value of the supply pressure P ₂ before the burner, and the measured valve opening S ′ of the flow rate control valve are: The actual flow coefficient N'of the burner is obtained by applying the flow rate coefficient V'of the flow rate adjustment valve obtained from the relationship between the valve opening degree S'of the flow rate adjustment valve measured in advance and the flow rate coefficient V '. N ′ is applied to the flow rate coefficient N of the burner of the formula (A) to calculate the flow rate coefficient V of the flow rate adjusting valves provided in the fuel supply system and the combustion air supply system, and the measured valve opening degree The deviation is calculated by comparing the flow coefficient V ′ for S ′ with the flow coefficient V obtained by the above calculation, and the deviation is calculated. (EN) A burner combustion control method for adjusting the valve opening so that the difference becomes zero, and a burner combustion control method for switching the combustion control method according to the operating state of the furnace.

[0026]

[Equation 6]

[0027]

1 and 2 show a facility 1 such as a heating furnace provided with burners 11A and 11B to which the burner control method according to the present invention is applied as heating means. In FIG. 1, the same elements as those in FIG. 4 are designated by the same reference numerals.

In this embodiment, a regenerative burner having a pair of burners 11A and 11B respectively having heat storage chambers 12A and 12B (hereinafter referred to as "regenerative burner").
Will be described. The regenerative burner, for example, sucks the combustion exhaust gas from the other burner 11B during the combustion of the one burner 11A, and the high temperature combustion exhaust gas is exhausted through the heat storage chamber 12B of the burner 11B, and in the meantime, inside the heat storage chamber 12B. The heat of the combustion exhaust gas is stored in the heat storage body. Then, after a lapse of a predetermined time, the burner in the exhaust gas is switched to the combustion state, and the burner in the combustion state is switched to the exhaust state, and the combustion air is supplied to the heat storage chamber 12B in which heat is stored to directly exchange heat, thereby increasing the temperature. The combustion air can be obtained with high efficiency. Then, the combustion state and the exhaust state are switched every predetermined time.

In the heating furnace 1 equipped with this regenerative burner, the temperature of the fluid in front of the burner changes (increases) as the furnace temperature rises. Therefore, when performing complex throttle control, the flow coefficient of the burner is fixed at a fixed value as in the conventional case. When treated as (fixed flow rate coefficient N), the flow rate coefficient actually fluctuates due to the change in the supply pressure caused by the temperature change (temperature rise), so that the valve opening required to maintain a predetermined air ratio is It wasn't.

Therefore, in the present embodiment, if the flow coefficient of the burner (fixed throttle means) changes due to the change of the fluid state when the temperature of the furnace is raised by using a regenerative burner or the like, the change is adjusted to the change. Flow coefficient (actual flow coefficient N ')
Performs compound aperture control. Hereinafter, this control will be described.

As described in the section "Prior Art", the composite throttle control is performed in the case where the burners 11A and 11B are fixed throttles, the flow coefficient N of the burner, the flow rate Q of the fluid, and the supply pressure P ₂ before the burner. And the flow coefficient V of the flow rate adjusting valve when the flow rate adjusting valve 5 is a variable throttle.
And the flow rate Q of the fluid and the differential pressure P ₁ at the flow rate adjusting valve 5 (Equation (2)), the supply pressure P ₀ on the primary side of the flow rate adjusting valve 5 and the differential pressure P at the flow rate adjusting valve 5. ₁ and the supply pressure P ₂ before the burner (equation (1) above), the flow rate Q, the flow rate coefficient V of the flow rate adjusting valve 5 and the burner 11A (or 11).
B) flow rate coefficient N and supply pressure P on the primary side of the flow rate adjusting valve 5
The relationship with ₀ (formula (1a)) is determined.

When the above equation (1a) is developed for the flow rate coefficient V of the flow rate adjusting valve 5, the flow rate coefficient V of the flow rate adjusting valve 5 is calculated by the flow rate Q, the flow rate coefficient N of the burner 11A (or 11B) and the supply pressure P. It is represented by the relationship with ₀ (the above formula (4)).

Here, the supply pressure P ₀ is obtained as a measured value, and the flow rate Q is determined in advance in accordance with the burner combustion amount determined from the deviation between the furnace temperature (measured value) and the set temperature. Further, in the conventional combined throttle control, the flow coefficient of the burner uses a value measured in advance for a certain flow rate as a fixed value (fixed flow coefficient N). I cannot respond to change.

Therefore, in the present invention, the above equation (2),
The relational expression (3a) between the flow coefficient N of the burner, the supply pressure P ₀ on the primary side of the flow rate adjusting valve 5 and the supply pressure P ₂ before the burner is obtained from (3).

[0035]

[Equation 7]

Here, the supply pressures P ₀ and P ₂ are measured values as described above, and the flow coefficient V ′ of the flow rate adjusting valve 5 is uniquely determined from the value S ′ obtained by actually measuring the opening degree of the flow rate adjusting valve 5. Since these values are determined, the actual flow coefficient N ′ can be calculated as a value according to the state of the fluid before the burner by applying these values to the equation (3a). Then, by applying this actual flow coefficient N ′ as the flow coefficient of the burner to the above equation (4), the flow coefficient according to the change of the supply pressure before the burner is calculated (actual flow coefficient N ′) to obtain an accurate value. Control can be performed.

By the way, the control characteristic of the fluid changes depending on whether the flow coefficient N of the burner is treated as a fixed value or as a variable value.

That is, when the flow rate coefficient N is treated as a fixed value, the turndown ratio of the combustion amount can be made large while the air ratio is kept within a predetermined error, but the change (fluctuation) of the fluid supply state is adjusted. The air ratio cannot be controlled. On the contrary, when the flow coefficient N is treated as a variation value, the turndown ratio of the combustion amount becomes small when the air ratio is kept within a predetermined error, but the air ratio control is performed with high accuracy according to the fluid supply state. It has the property that

The difference in the characteristics depends on whether or not the equation for calculating the flow rate includes the item of the differential pressure. That is, the following formula (1b) obtained by expanding the formula (1a) with respect to the flow rate Q.
When considering the flow coefficient N of the burner as a variation value, the above equation (3a) is substituted into the equation (1b) to obtain the flow rate Q. Therefore, the differential pressure of the flow rate adjusting valve 5 is calculated in the equation (1b). Since the item (P ₀ −P ₂ ) is included, the flow rate adjusting valve 5 has the same characteristic as the error of the orifice type flow rate measurement due to the drift error of the differential pressure sensor shown in FIG.
Whereas a large turndown ratio cannot be achieved,
When the flow coefficient N of the burner is treated as a fixed value, the formula (1
Since the differential pressure item is not included in b), a differential pressure sensor is not required and a drift error does not occur. Therefore, the opening degree of the flow rate adjusting valve 5 has almost no influence on the turndown ratio.

[0040]

[Equation 8]

That is, during normal operation in which the furnace is operating in a steady state, the flow coefficient N of the burner is treated as a fixed value to keep the air ratio constant and adjust to the fluctuation of the material throughput. While the combustion amount can be changed significantly by using a regenerative burner, etc., the flow coefficient N of the burner can be changed to a variable value when the furnace is starting up when the fluid supply state before the burner is not stable. The air ratio can be kept constant in accordance with the change (fluctuation) of the fluid supply state before the burner.

In actual operation, a region in which the flow coefficient of the burner is treated as a fixed value (fixed flow coefficient N) and a region in which the actual measured value (actual flow coefficient N ') is used are set in advance, and the flow rate is set in each area. Switch the coefficient to use.

This switching is performed, for example, with respect to the target furnace temperature of 1200 ° C., the measured furnace temperature is a specific temperature, for example, 10
When the temperature reaches 00 ° C, the control using the actual flow coefficient N'is switched to the control using the fixed flow coefficient N, or when the measured furnace temperature reaches a predetermined ratio of 1200 ° C (for example, 95%), use It can be set according to the convenience of the person.

In this way, by switching the fixed flow coefficient N and the actual flow coefficient N'as the flow coefficient of the burner in accordance with the supply state of the fluid before the burner, the air ratio is stably maintained over the entire operation of the furnace. Can be kept at

The composite throttle control using the actual flow coefficient N'is not limited to the start-up of the furnace using the regenerative burner. For example, combustion air such as a high-speed jet burner, fuel gas, etc. Can be applied to any burner whose back pressure affects the primary side of the burner when the nozzle tip of the nozzle is squeezed at high speed, that is, any burner in which the fluid supply state before the burner is not stable. .

[0046]

As is apparent from the above description, in the burner control method using the composite throttle control according to the present invention, the burner is determined by actually measuring the pressure and the valve opening to determine the actual flow coefficient of the burner. Since the flow rate coefficient can be treated as an actual measurement value according to the fluid supply state, combustion control can be performed with a stable air ratio even when the fluid supply pressure changes before the burner. Further, by changing the flow coefficient of the burner according to the operating state of the furnace, the air ratio can be kept constant throughout the operation of the furnace.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a heating furnace using a regenerative burner to which the present invention is applied.

FIG. 2 is a schematic diagram showing a regenerative burner.

FIG. 3 is a diagram showing an error in orifice type flow rate measurement due to a drift error of a differential pressure sensor.

FIG. 4 is a schematic view showing a conventional burner.

[Explanation of symbols]

1 heating furnace 2 Temperature control device 3 Burner control device 4,11A, 11B burner 5 Flow control valve 12A, 12B heat storage chamber

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) F23N 5/18

Claims (2)

(57) [Claims] 1. A burner flow coefficient N set as a fixed value in advance, a fuel flow rate set in advance for the combustion amount of the burner, and a combustion flow rate obtained from the fuel flow rate and a preset air ratio. The measured value of the supply pressure P ₀ is given by the following formula (A) showing the relationship between the flow rate of air and the supply pressure P ₀ of the fluid on the primary side of the flow rate adjusting valve provided in the fuel supply system and the combustion air supply system. Is applied to calculate the flow rate coefficient V of the flow rate adjusting valves provided in the fuel supply system and the combustion air supply system, respectively, and the relationship between the valve opening degree S ′ of the flow rate adjusting valve and the flow rate coefficient V ′ is calculated in advance. The air ratio is kept constant by actually measuring and comparing the measured flow coefficient V ′ with the flow coefficient V obtained by the above calculation to obtain a deviation and adjusting the valve opening so that the deviation becomes zero. Burner fuel that controls the amount of combustion while being held at The control method, the relationship between the supply pressure P ₂ and the fluid flow rate Q and the burner of the flow coefficient N of the fluid before the burner in the case of the fixed throttle burner, and the flow rate adjustment in the case where the flow control valve and the variable throttle The differential pressure P ₀ -P ₂ of the fluid at the valve, the flow rate Q of the fluid, and the flow rate coefficient V of the flow rate adjusting valve are introduced into the following equation (B) to supply pressure P on the primary side of the flow rate adjusting valve. The actual flow coefficient of the burner is applied by applying the measured value of _0, the measured value of the supply pressure P ₂ before the burner, and the flow coefficient V ′ of the flow adjustment valve obtained from the measured valve opening S ′ of the flow adjustment valve. A burner characterized in that N ′ is obtained, and this actual flow coefficient N ′ is applied in place of the flow coefficient N of the burner in the above formula (A), and the flow coefficient of the burner is set as a variation value according to the state of the fluid. Combustion control method. [Equation 1] 2. A burner flow coefficient N set as a fixed value in advance, a fuel flow rate set in advance for the combustion amount of the burner, and a combustion flow rate obtained from the fuel flow rate and a preset air ratio. The measured value of the supply pressure P ₀ is given by the following formula (A) showing the relationship between the flow rate of air and the supply pressure P ₀ of the fluid on the primary side of the flow rate adjusting valve provided in the fuel supply system and the combustion air supply system. Is applied to calculate the flow rate coefficient V of the flow rate adjusting valves provided in the fuel supply system and the combustion air supply system, respectively, and the relationship between the valve opening degree S ′ of the flow rate adjusting valve and the flow rate coefficient V ′ is calculated in advance. A burner combustion control method in which actual measurement is performed, a deviation is obtained by comparing the measured flow coefficient V ′ with the flow coefficient V obtained by the above calculation, and the valve opening is adjusted so that the deviation becomes zero. , Burner with fixed throttle Relationship between the supply pressure P ₂ and the fluid flow rate Q and the burner of the flow coefficient N of the fluid in, and,
When the flow control valve is a variable throttle, the following equation (B) is derived from the relationship between the fluid pressure difference P ₀ -P ₂ at the flow control valve, the flow rate Q of the fluid, and the flow coefficient V of the flow control valve. The flow control valve measured in advance with respect to the measured value of the supply pressure P ₀ on the primary side of the flow control valve, the measured value of the supply pressure P ₂ before the burner, and the measured valve opening S ′ of the flow control valve. The actual flow coefficient N'of the burner is obtained by applying the flow coefficient V'of the flow rate adjusting valve obtained from the relationship between the valve opening degree S'of FIG. A) burner flow coefficient N
To calculate the flow rate coefficient V of the flow rate adjusting valves provided in the fuel supply system and the combustion air supply system, and to calculate the flow rate coefficient V'for the measured valve opening S'and the flow rate obtained by the calculation. The burner combustion control method is characterized in that a deviation is obtained by comparing with the coefficient V, and the burner combustion control method in which the valve opening is adjusted so that the deviation becomes zero, and the burner combustion control method is switched according to the operating state of the furnace. Method. [Equation 2]