JPH0449007B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a control system for controlling combustion and cooling of a firing furnace or the like using tertiary air.

(Prior Art) Conventionally, in a firing furnace, as shown in FIG.
Fuel and air are supplied to the firing burner 1 through a fuel supply pipe 2, a primary air supply pipe 3 for atomization, a secondary air supply pipe 4 for combustion, and a tertiary air supply pipe 5 for combustion and cooling.
The respective flow control valves V ₁ , V ₂ , V ₃ and
It is known to supply via V ₄ and use an electric motor as an actuator to control the flow control valves V ₁ to V ₄ for firing and cooling.

In the above-mentioned conventional control system that controls combustion and cooling using tertiary air, the temperature of the firing furnace is gradually raised to a predetermined firing temperature as shown in heat curve A shown in Figure 10 during combustion. In order to control the air-fuel ratio m as shown by the broken line curve B, the control valves V ₁ , V ₂ and V ₃ are interlocked controlled by one common motor M ₁ and the tertiary air flow control valve It was necessary to control V ₄ with a separate motor M ₂ .

Therefore, the conventional control circuit for motors M ₁ and M ₂ uses a temperature programmer PR as shown in FIG.
1 and valve opening programmer PR2 to controller CR1 for motor _M1 and controller for motor _M2
The temperature programmer PR1 and the valve opening degree programmer PR2 are connected to the controllers CR1 and CR2 via the controller switching relay R1, and in the baking process, the temperature programmer PR1 is connected to the motor M controller for ₁
Connect to CR1 and valve opening programmer PR
2 is connected to controller CR2 for motor _M2 , and when transitioning from the firing process to the cooling process, the connection is switched by controller switching relay R1 to connect temperature programmer PR1 to the controller for motor M2, and valve opening programmer PR2 is connected to controller _CR2 for motor M2. The motor M ₁
Connect to controller CR1 for motor M ₁
It was necessary to reverse the characteristics of the controller.

(Problem to be Solved by the Invention) As described above, the conventional control system separately controls the fuel and primary and secondary air flow control valves and the tertiary air flow control valve during firing and cooling. Since it is necessary to control the two motors separately, the control system becomes complicated and expensive.

It is an object of the present invention to solve the above-mentioned problems and to simplify the configuration of a control system and provide it at low cost.

(Means for Solving the Problems) According to the present invention, the firing burner includes fuel and
Secondary, secondary and tertiary air is controlled and supplied by flow control valves V ₁ , V ₂ , V ₃ and V ₄ provided in each supply pipe, and these flow control valves V ₁ to V ₄ are controlled by a temperature programmer. In the combustion cooling control system, the valve opening degree and flow rate of the tertiary air flow control valve V ₄ are controlled by the fuel, primary and secondary air flow control valves V ₁ ,
The air flow control valves V ₁ to _{V 4} are controlled by being connected to a common actuator so that the opening degrees and flow rates are opposite to those of V ₂ and V ₃ .

(Function) According to the present invention, the combustion and cooling tertiary air flow rate control valve _V4 is connected to a common actuator so that the valve opening degree is opposite to the valve opening degree of the other fuel and air flow rate control valves. By this, it is possible to perform firing by controlling all the flow rate control valves V ₁ to _{V 4} provided in the fuel and air supply pipes in conjunction with each other by a common motor M, and also to perform the firing from the firing process to the cooling process. Even during the transition, the temperature programmer can control the motor M in one series via the motor M controller to perform desired combustion and cooling control without switching the controller.

(Example) An example of the present invention is shown in FIGS. 1 to 6. In the illustrated example, the firing burner 1 includes fuel and primary,
Fuel supply pipe 2 for supplying secondary and tertiary air, primary air supply pipe 3 for atomization, secondary air supply pipe 4 for combustion
A tertiary air supply pipe 5 for combustion and cooling is provided, and flow control valves V ₁ , V ₂ , V ₃ are installed in these supply pipes.
and V ₄ are provided respectively.

Among these flow control valves, the tertiary air flow control valve
They are connected to a common actuator so that the valve opening and flow rate of V ₄ are opposite to those of the primary and secondary air flow control valves V ₂ and V _3. For example, the primary air flow control valve for atomization The air flow rate control valve V ₂ and the combustion secondary air flow rate control valve V ₃ are shown in Figures 2 and 3.
As shown in the figures, the flow rate increases in proportion to the increase in the opening degree of the valve _V1 , and at the same time, the combustion and cooling tertiary air flow rate control valve _V4 increases as the opening degree of the valve _V1 increases. They are connected to a common actuator so that the flow rate decreases in proportion to the increase in opening.

In the illustrated example, flow control valves V ₁ to _{V 4} of the same structure
valve to motor M, which is one common actuator.
When V ₁ to _{V 3} are in the fully open position, valve V ₄ is in the fully closed position, so that they are linked and interlocked, and as a result, a total air flow rate proportional to the valve opening is obtained as shown in Figure 5. The desired air-fuel ratio can be obtained.

The motor M is connected to be controlled in series by a controller CR1 connected to a temperature programmer PR1, as shown in FIG.

According to the above configuration, during firing in the firing furnace, the motor M is controlled to increase the valve openings of the flow rate control valves V ₁ to _{V 3} and at the same time decrease the valve opening of the flow rate control valve V ₄ .
This allows the combustion gas temperature in the kiln to be lowered from 150℃.
It can be heated up to 1500℃, and during cooling, the motor M is controlled to reduce the valve openings of valves V ₁ to _{V 3} and at the same time increase the valve opening of V ₄ to increase the amount of air. The inside of the firing furnace can be cooled by cooling the inside of the firing furnace. For this reason, 150℃~ with one line of control equipment.
Combustion gas at 1500℃ can be obtained continuously.

FIG. 7 shows another embodiment of the combustion and cooling control system according to the present invention, in which the fuel supply pipe 2 can be adjusted to supply fuel to the firing burner 1 by means of a fuel pump (not shown). A pilot pressure pipe ₆ is provided from the secondary air supply pipe between the combustion secondary air flow control valve V ₃ and the firing burner 1 to the fuel flow control pressure equalization valve V ₅ . is configured to supply _fuel control pressure _P There is. In the figure, the same parts as in FIG. 1 are indicated by the same reference numerals, and have the same effects as the combustion and cooling control system shown in FIG. 1.

(Effects of the Invention) According to the present invention, the configuration of the control system can be made significantly simpler and cheaper than the conventional one.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the combustion and cooling control system of the present invention, Figure 2 is a graph showing the characteristics of the flow rate control valve for the primary air for atomization, and Figure 3 is the flow rate control valve for the secondary air for combustion. Figure 4 is a graph showing the characteristics of the combustion and cooling tertiary air flow rate control valve, Figure 5 is the total air flow rate through the primary, secondary and tertiary air flow rate control valves. The graph shown in FIG. 6 is a block circuit diagram for controlling the motor M shown in FIG.
Fig. 7 is a schematic diagram showing another embodiment of the combustion and cooling control system of the present invention, Fig. 8 is a schematic diagram of a conventional combustion and cooling control system, and Fig. 9 is a schematic diagram showing the motor M shown in Fig. 3. ₁ and M ₂ control block diagram, 1st
FIG. 0 is a graph showing the relationship between firing and cooling times of the firing furnace and temperature. 1... Burner for firing, 2... Fuel supply pipe, 3...
...Primary air supply pipe, 4...Secondary air supply pipe for combustion, 5...Tertiary air supply pipe for combustion and cooling,
V ₁ to V ₄ ...Flow control valve.

Claims (1)

[Claims] 1. Primary air for atomization, secondary air for combustion, and tertiary air for combustion and cooling are controlled and supplied to the firing burner by flow control valves V ₂ , V ₃ and V ₄ provided in the respective supply pipes. In a combustion and cooling control system where the flow rate control valves V ₂ to _{V 4} are controlled by a temperature programmer, the valve opening degree and flow rate of the tertiary air flow control valve V ₄ are the same as those of the primary and secondary air flow control valves V ₂ and V. A combustion and cooling control system for a firing furnace, etc., characterized in that the air flow rate control valves V ₁ to V ₄ are connected to a common actuator and controlled so that the opening degree and flow rate are opposite to those of _{No. 3} .