JPS6183824A - Fuel control device - Google Patents

Abstract

PURPOSE:To optimize the ratio of fuel volume versus air volume to be supplied into a combustion furnace in thinned out operation by a method wherein a variable air volume characteristic to be supplied to a fuel burner corresponding to the fuel amount to the same, being memorized in a plurality are provided as characteristic storage measures. CONSTITUTION:When a combustion load is being decreased, the output of temperature adjusting indicator 21 is becoming small. And upon reaching the temperature below certain constant value, both a fuel control electromagnetic valve 11 and an air control electromagnetic valve 17 are magnetized to close their valves. As a result, the burner in operation 5 is stopped and the remaining burner 3 is only in operation, also, a change-over device 29 is actuated for switching to the second characteristic data memory 33. An air ratio compensating value, correlating with a fuel flow rate detected by fuel flow meter 7, is read-out from the storage data in the second characteristic data memory 33, then in a adder 35 it is added on the standard air ratio and is supplied to the air adjusting indicator 37 through a multiplier 25, subsequently, air regulating valve 15 is properly controlled based on this compensated reference air ratio.

Description

Detailed Description of the Invention [Technical Field of the Invention 1] This invention relates to a combustion furnace in which a plurality of combustion burners are thinned out according to the combustion load, and in which the ratio of the amount of fuel to the amount of air supplied to the combustion furnace during thinning is determined. Regarding the arm control device that optimally controls the

[Technical background of the invention and its problems] Combustion P having a plurality of combustion parts For example, in batch furnaces, continuous furnaces, boilers, etc., combustion burners are thinned out depending on the combustion load. The fuel flow type to air ratio supplied to the combustion burner was controlled in the same way whether the burners were not thinned out or when the burners were thinned out. In detail, conventional combustion control devices have burner characteristic curve data in which the air ratio correction value Δμ is plotted against the supplied fuel flow, and from this data, the air ratio correction value according to the fuel flow rate is calculated. Read out Δμ, add this air ratio correction value Δμ to a predetermined reference air ratio μ (ratio of 4-air air group to fuel flow rate), correct the air ratio, and calculate the air ratio corresponding to this corrected air ratio. Air is supplied to the combustion burner. However, although the above burner characteristic curve data is necessarily data when the combustion burners are not thinned out, this same data is conventionally used also when the combustion burners are thinned out. In this case, the air 1 h correction value was not suitable, and black smoke was generated or there was excess air (efrich), which worsened the combustion efficiency.

``Purpose of the Invention This invention has been made in view of the above, and its purpose is to provide a combustion furnace in which a plurality of combustion burners are thinned out according to the combustion load. It is an object of the present invention to provide a combustion control device that can appropriately control the ratio of the amount of fuel to be supplied to the amount of air.

U Summary of the Invention] In order to achieve the above object, the present invention provides a characteristic storage means that stores a plurality of change characteristics of the amount of air to be supplied to the fuel burner with respect to the amount of fuel supplied to the combustion burner; selection means for selecting a change characteristic from among the change characteristics stored in the characteristic storage means according to the number of combustion burners used;
The gist of the present invention is to include a control means for controlling the amount of air supplied to the combustion burner in accordance with the amount of fuel supplied to the combustion burner using the change characteristics selected by the selection means.

[Embodiment J of the invention An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention.

In the figure, there are two combustion burners 3.5 in the combustion furnace 1.
is installed. One combustion burner 3 is directly supplied with fuel via a fuel flow meter 7 and a fuel control valve 9, and the other combustion burner 5 is supplied with fuel via a fuel flow meter 7115 and a fuel control valve 9. Fuel is supplied via valve 11. Further, air is directly supplied to the combustion burner 3 via an air flow meter 13 and an air control valve 15, and air is supplied to the combustion burner 5 via an air flow meter 13 and an air control valve 15, and a solenoid valve 17 for air control is supplied to the combustion burner 5 via an air flow meter 13 and an air control valve 15. Air is supplied through. The fuel control solenoid valve 11 and the air control solenoid valve 17 are energized and closed to stop the supply of fuel and air to the combustion burners 5 when the combustion burners 5 are thinned out and only the combustion burners 3 are used. It is something.

The temperature inside the combustion furnace 1 is detected by one temperature detector and supplied to a temperature controller 21. The temperature controller 21 compares and monitors the detected temperature with a set temperature, and the output of the temperature controller 21 is supplied to a fuel regulator 23 and a multiplier 25. The fuel controller 23 adjusts the output signal for controlling the amount of fuel supplied to the combustion burners 3 and 5 based on the signal J5 related to 4 degrees from the temperature controller 21 and the fuel flow rate from the fuel flow meter 7. valve 9, which controls the fuel control valve 9 to supply the appropriate amount of fuel to the combustion burner 3,
5. Further, the output of the temperature controller 21 is monitored by a monitor switch 27, and when the output of the temperature controller 21 falls below a certain value, the monitor switch 27 detects this and operates, and the fuel control electromagnetic The valve 11 and the air control solenoid valve 17 are operated to stop the supply of fuel and air 1 to the combustion burners 5, and the ail control is performed to thin out the combustion burners 5. The fact that the output of the temperature controller 21 mentioned above has fallen below a certain value may mean, for example, that the volume or size of the combustible material has become smaller, or that the combustion energy has increased due to vigorous combustion in the initial stage and the desire to maintain the state of one product after that. It is in a state where it is not necessary that much.

Furthermore, the output of the monitor switch 27 is used to control two switching devices. The switch 29 includes a first characteristic data storage device 3 in which burner characteristic curve data for normal use is recorded.
1 and a second characteristic data storage device 33 in which burner characteristic curve data for thinning control are described, and an output of the switch 29 (an adder 35 is also connected.
The characteristic data storage device 31a'3 and the second characteristic data storage device 33 have, for example, a characteristic curve in which the horizontal axis represents the fuel flow rate and the vertical axis represents the air ratio correction value Δμ. 1-1 It stores data on the fuel flow rate detected by the fuel flow meter 7, and determines the amount of air to avoid complete combustion of the fuel meteor. The air ratio correction value Δμ is cut and output to the adder 35 via u Z 29. The I'll compiler 35 appropriately corrects the air ratio μ by adding this air ratio correction value Δμ to the L air ratio μ. The storage device d31 is for normal operation, that is, for combustion using two combustion burners 3.5 in this embodiment without thinning out the combustion burners, and the second characteristic data storage device 33 is for combustion using two combustion burners 3.5. This is a case where only one combustion burner 3 is used by thinning out the combustion burners 5,
These changes are performed by a switch 29 under the control of a monitor switch 27. The base Q air ratio μ which has been added and corrected by the air ratio correction value Δμ in the adder 35 is supplied to the air conditioning unit via the multiplier 25, and the air conditioner 37 receives this corrected reference air ratio μ and the air flow meter. The air control valve 15 is controlled based on the air port detected in step 13 to supply an appropriate amount of air to each combustion burner.

Next, the operation of this embodiment will be explained.

First, if there is no thinning E), that is, combustion burner 3
, 50 are used to perform combustion control. In this case, fuel is supplied to the combustion burner 3 via the fuel flow meter 7 and the fuel control valve 9, and further via the fuel IL control solenoid valve 11 to the combustion burner 5.

In this case, the fuel (for Kitahin, the fuel is detected by the fuel flow meter 7 and
, the IT adjustment meter 23, the first characteristic data storage device 31, and the second characteristic data storage device 633, respectively. Further, the temperature inside the combustion furnace 1 is detected by a temperature detector 1 and supplied to a temperature controller 21. In this case, both the combustion burners 3 and 5 are operating and the temperature inside the combustion furnace 1 is high, so the output of the temperature controller 21 is high, so the monitor switch 27 is not operating. Therefore, the fuel control solenoid valve 11J5 and the air control solenoid valve 17 are not energized and remain closed, and the combustion burner 5 is in operation. Mar
ζ, the switch 29 is switched to the first characteristic data storage device 31 side by the output of the monitor switch 27 of (4),
From the first characteristic data storage device 31, an air ratio correction value Δμ corresponding to the fuel flow rate supplied from the fuel flow meter 7 at this time, that is, an air ratio correction value Δμ for normal times (two pipes) is sent to the adder. 35. This air ratio correction value Δμ is added to the reference air ratio μ in the adder 35, and this corrected reference air ratio is supplied to the air regulator 37 via the multiplication hole 25, thereby controlling the air regulating valve 15 appropriately. Controlling and supplying the combustion burners 3 and 5 with an air amount that matches the fuel flow rate,
The fuel from both combustion burners is completely combusted.

Next, the case of thinning control will be explained. When combustion is controlled using the two combustion burners 3 and 5 as described above, when the combustion load decreases, the output of the temperature controller 21 decreases. When the value falls below a certain value, the monitor switch 27 detects this and excites the fuel control solenoid valve 11 and the air control solenoid valve core to close the valves. As a result, the use of the combustion burners 5 is stopped (thinned out) so that only the combustion burners 3 are used, and the two switchers are operated to switch to the second characteristic data storage device 33 side. The air ratio correction value Δμ for the fuel flow rate detected by the fuel flow meter 7 is read from the data stored in the second characteristic data storage unit 633 and sent to the adder 3.
5 is added to the reference air ratio μ and supplied to the air controller 37 via the multiplier 25. The air regulator 37 appropriately controls the air regulating valve 15 according to the corrected reference air ratio, supplies the combustion burner 3 with an air amount that matches the fuel flow rate, and completely burns out the fuel from the combustion burner 3. It is.

In the first embodiment, the case where the number of combustion burners is two was explained, but the number of combustion burners is not limited to two, and the thinning stage is also performed in two stages in this embodiment. Although the case has been described, it is not limited to two stages. Furthermore, it goes without saying that the thinning control can be carried out not only by using combustion burners of the same capacity Φ, but also by using combustion burners of different capacities and selecting them as appropriate. Furthermore, the thinning may be controlled not by the output of the temperature controller 21 but by the measured value of the fuel controller 23.

[Effect of the invention] As explained above, according to this invention, 2 yen 1
Among the stored change characteristics of the air amount with respect to the fuel amount, a change characteristic is selected according to the thinned out combustion burner,
This is used to control the air (2) supplied to the combustion burners, so even if the combustion burners are thinned out and the number of burners decreases, or even if they are not thinned out and the number of burners is large, the combustion The ratio of the amount of fuel supplied to the burner to the amount of air can be optimally controlled according to the number of burners, so that the fuel from the burner is completely combusted.
It burns efficiently without producing black smoke or creating excess air.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a combustion control device showing one embodiment of the present invention. 1... Combustion furnace 3, 5... Combustion burner 7.
...Fuel flow meter 11...Fuel control solenoid valve 13
...Air flow meter 17...Air control solenoid valve 2
1... Temperature controller 23... Fuel regulator 27.
...Monitor switch 29...Switcher 31...1st
Characteristic data storage device 33...Second characteristic data storage device 35...H11 calculator 37...Air conditioner Fig. 1

Claims (1)

[Claims] In a combustion furnace in which a plurality of combustion burners are thinned out according to the combustion load, a characteristic storage means stores a plurality of change characteristics of the amount of air to be supplied to the fuel burner with respect to the amount of fuel supplied to the combustion burner; A selection means for selecting a change characteristic according to the number of combustion burners used from among the change characteristics stored in the characteristic storage means, and an amount of fuel supplied to the combustion burner using the change characteristic selected by the selection means. 1. A combustion control device comprising: control means for controlling the amount of air supplied to a combustion burner according to the amount of air supplied to the combustion burner.