JPH0141004Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an oxygen-enriched combustion control device, and in particular to an oxygen-enriched combustion control device, in particular, the air ratio in a combustion device that burns fuel using combustion air with increased oxygen concentration using an oxygen selective permeation membrane. Regarding a control device.

Combustion devices that achieve high temperatures by burning fuel using oxygen-enriched air using an oxygen selective permeation membrane have already been realized, but in such combustion devices, changes in the combustion load Therefore, it is desirable to be able to arbitrarily change the air ratio.

The present invention has been made based on the above-mentioned viewpoint, and an object of the present invention is to provide an oxygen-enriched combustion control device that can arbitrarily change the combustion air ratio.

This invention supplies oxygen-enriched air through an air supply pipe by suctioning the downstream side of an oxygen selective permeation membrane with a suction pump, and also supplies fuel through a fuel supply pipe for combustion. In the air ratio control device for a combustion device, an air flow meter and an oxygen concentration analyzer are provided in the middle of the air supply pipe, a fuel flow meter is provided in the middle of the combustion supply pipe, and the air flow rate is adjusted. , means for calculating an air ratio based on the oxygen concentration and the fuel flow rate, and controlling the rotation speed of the suction pump so that the calculated air ratio becomes equal to a preset air ratio, is provided with a flow rate control valve, and the control means is provided with a function of controlling the opening degree of the flow rate control valve so that the detected value of the temperature detector for detecting the combustion temperature becomes equal to a preset value. This is a unique oxygen-enriched combustion control device.

FIG. 1 is a system diagram of an embodiment of the present invention.
Fuel, such as city gas, is supplied to the burner 2 of the combustion furnace 1 via a fuel supply pipe 3. Further, the combustion air enriched with oxygen by the oxygen-enriched air generating means 5 equipped with the oxygen selectively permeable membrane 4 is supplied to the suction pump 6
The air is supplied to the burner 2 via an air supply pipe 8 equipped with a blower 7 . By combusting the fuel with oxygen-enriched combustion air in this manner, high-temperature combustion can be achieved in the combustion furnace 1.

An oxygen concentration analyzer 9 and an air flow meter 10 are provided in the middle of the air supply pipe 8, and the detected values by the oxygen concentration analyzer 9 and air flow meter 10 are as follows.
It is input to the control means 11. Further, a fuel flow meter 12 and a flow control valve 13 are provided in the middle of the fuel supply pipe 3.
The detected value by the fuel flow meter 12 is input to the control means 11. Furthermore, combustion furnace 1
is provided with a temperature detector 14 , and the temperature detected in the combustion furnace 1 by this temperature detector 14 is input to the control means 11 .

The control means 11 has a function of directing the amount of oxygen in the air supplied to the burner 2 based on the detected value by the oxygen concentration analyzer 9 and the detected value by the air flow meter 10, and the function of controlling the amount of oxygen and fuel that is calculated. It has a function of calculating an air ratio based on the value detected by the flow meter 12. Furthermore, in the control means 11,
The air ratio is set in advance, and the set air ratio is compared with the calculated air ratio, and the rotation speed of the suction pump 6 is adjusted so that the calculated air ratio is approximately equal to the set air ratio. A signal is given to regulator 15 for the change. Also, the temperature detector 14
The control means 11 controls the opening degree of the flow rate control valve 13 so that the detected temperature becomes equal to a preset temperature.

In this way, the combustion amount of the burner 2 in the combustion furnace 1 is controlled so that the temperature inside the combustion furnace 1 is set in advance, and the combustion air ratio is controlled by the control means 11 by the rotation of the suction pump 6. Automatically adjusted by changing the number.

The advantage of varying the rotational speed of the suction pump 6 for adjusting the combustion air ratio will now be explained. As shown in FIG. 2, conventionally, a centrifugal blower 18 such as a turbo blower is used to supply combustion air to the burner, and a butterfly valve 19 supplies the combustion air to the burner. When the butterfly valve 19 is moved in the closing direction, the air volume decreases and the motive power (ie, electric power) of the blower 18 also decreases. Further, in the conventional configuration shown in FIG. 3 in which oxygen-enriched air is supplied to the burner, oxygen-enriched air is supplied from the butterfly valve 22 via the oxygen selective permeation membrane 20 and the suction pump 21.

FIG. 4 shows the line l1 showing the characteristics of the suction pump 6 used in the embodiment of FIG. 1 and the suction pump 21 shown in FIG.
indicates the relationship between suction pressure and flow rate, and line l
2 shows the relationship between suction pressure and power (electric power).

FIG. 5 shows the oxygen selective permeable membrane 4 shown in FIG.
3 shows the characteristics of the oxygen selectively permeable membrane 20 shown in FIG. Line 13 shows the relationship between suction pressure and flow rate of the oxygen selectively permeable membrane, and line 14 shows the relationship between suction pressure and oxygen concentration.

In the configurations shown in FIGS. 3 to 5, if the butterfly valve 22 is moved in the closing direction to reduce the flow rate, as shown in FIG. 4, the suction pressure will increase and the power will increase. Also, from FIG. 5, the oxygen concentration and flow rate tend to increase. In other words, the characteristics of the suction pump 21 and the characteristics of the oxygen selectively permeable membrane 20 are, so to speak, inconsistent. In reality, the pressure between the suction pump 21 and the butterfly valve 22 increases, and the suction pressure of the oxygen selectively permeable membrane 20 by the suction pump 21 decreases.

On the other hand, the relationship between flow rate Q and pressure P is Q∝√. Therefore, even if the butterfly valve 22 is set in the closing direction to reduce the flow rate, the suction pump 2
1 and the butterfly valve 22 increases, and even if the butterfly valve 22 is moved in the closing direction, the flow rate decreases little and the power does not decrease. Accurate control of the flow rate, and therefore of the air ratio, is therefore not possible, and is also expensive and uneconomical.

In order to solve this problem, in the present invention, the rotation speed of the suction pump 6 is controlled. As the rotational speed of the suction pump 6 is decreased by controlling the rotational speed, both the flow rate and the oxygen concentration decrease, as is clear from FIG. 5. In addition, in the present invention, the power consumption can be significantly reduced compared to the configuration shown in FIG. 3.

As described above, according to the present invention, the suction pump is controlled so that the combustion air ratio of fuel in the combustion means is equal to a preset value, thereby achieving stable combustion at a constant air ratio. be able to. Further, the opening degree of the flow control valve is controlled so that the detected value of the temperature detector that detects the combustion temperature becomes a preset value, and thus the temperature of the combustion means is maintained at a desired value.

Furthermore, in the present invention, the rotational speed of the suction pump is controlled, so that, for example, when the rotational speed is reduced, both the flow rate of the combustion air and its oxygen concentration are reduced, thus precisely controlling the combustion air ratio. At the same time, it is possible to reduce the power consumption.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of an embodiment of the present invention, Fig. 2 is a diagram showing a conventional configuration for supplying combustion air,
FIG. 3 is a diagram showing a conventional configuration for supplying oxygen-enriched air for combustion, and FIG. 4 is a diagram showing the suction pumps 6, 21.
Figure 5 shows the characteristics of the oxygen selectively permeable membranes 4 and 2.
0 is a diagram showing the characteristics of 0. 1... Combustion furnace, 2... Burner, 3... Fuel supply pipe, 4... Oxygen selective permeation membrane, 6... Suction pump,
8...Air supply pipe, 9...Oxygen concentration analyzer, 10
... air flow meter, 11 ... control means, 12 ... fuel flow meter, 13 ... flow control valve, 14 ... temperature detector, 15 ... regulator.

Claims (1)

[Claim for Utility Model Registration] Air enriched with oxygen is supplied via an air supply pipe by suctioning the downstream side of the oxygen selective permeation membrane with a suction pump, and fuel is supplied via a fuel supply pipe. In the air ratio control device for a combustion device configured to perform combustion, an air flow meter and an oxygen concentration analyzer are provided in the middle of the air supply pipe, and a fuel flow meter is provided in the middle of the fuel supply pipe. means for calculating an air ratio based on the air flow rate, oxygen concentration, and fuel flow rate, and controlling the rotation speed of the suction pump so that the calculated air ratio becomes equal to a preset air ratio; A flow control valve is provided in the middle of the supply pipe, and the control means has a function of controlling the opening degree of the flow control valve so that a detected value of a temperature detector for detecting combustion temperature becomes equal to a preset value. An oxygen-enriched combustion control device comprising: