JPS597824A - Method for monitoring flame pattern - Google Patents

Abstract

PURPOSE:To monitor the state of combustion by a flame pattern, by previously memorizing the pattern of the root of a flame, and by calculating the deviation of a detected flame pattern from corresponding part of the memorized one, after the detected flame pattern is functionally processed by a weighted coefficient. CONSTITUTION:Fuel being fed to a burner 1 is burned in the furnace 7 of a boiler, and water in heat transfer pipes 3 is turned into steam by heat. An image fiber 5 and a cooler 4 for the image fiber 5 are fitted to the wall of a furnace in order to monitor the state of combustion in the furnace 7. Flames are classified by characteristics, and the deviation of a detected flame pattern, which is functionally processed by a weighted coefficient (h), is calculated from the flame pattern which is previously memorized. By this method, the state of detected flame pattern can be monitored more accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for monitoring the combustion state inside a furnace of a power generation boiler, and particularly to a flame shape monitoring method most suitable for application to a boiler used for thermal power generation.

Conventionally, the only way to know the combustion state from the flame in the boiler furnace is to monitor the flame during combustion using an ITV'fr: installed on the opposite wall of the burner nozzle, or to monitor it through a viewing window installed on the furnace wall. Inspection methods and temperature control of heat transfer tubes were the mainstream, and the only automatic monitoring device used was a flame detector to determine automatic burner ignition and extinguishment for the furnace body layer.

Moreover, regarding the monitoring of the combustion state during boiler operation, there was no quantified output value, so operators had to rely on experience and intuition, which often resulted in the problem of not being able to take immediate action.

In addition, when monitoring the combustion status using a TV, the burner nozzle on the opposite wall is monitored using the ITVt attached to the furnace wall, so the flame swirls during operation, making it difficult to accurately judge the combustion status. This was difficult and relied on the operator's experience and intuition.

An object of the present invention is to provide a method for monitoring the combustion state inside the furnace of a power generation boiler based on the flame shape.

The present invention focuses on the fact that the shape and properties of flames are characterized by stable regions, detects flames with an image fiber, etc., and stores the results of weighting according to the stability of the flame shape in advance. It is characterized by monitoring the combustion status by comparing it with a standard flame pattern.

An overview of the present invention is shown in FIG. In FIG. 1, the purpose of the boiler is to combust fuel supplied from a burner 1 in a furnace 7 and to convert water in heat exchanger tubes 3 into steam. Therefore, in order to monitor the combustion state in the furnace 7, the image fiber 5 and its cooling device 4 are attached to the wall surface of the furnace 7, for example.

An example of the mounting direction and its angle when the viewing angle is θ is shown in FIG.

The mounting angle is such that the base of the flame 2 at the tip of one or more burners 1 can be detected, and the mounting position is determined by the viewing angle θ of the image fiber 5.

For example, an image signal (light) of the base of the flame 1 detected by a detection unit having such a structure is converted into an analog signal (electricity) by the imaging device 6, and converted into a digital signal by the A/D converter 8. It is changed and taken into the electronic computer 9.

An embodiment of the invention is shown in FIG. When the burners 1 are provided facing each other or in multiple stages (rows), it is necessary to install and monitor a plurality of image fibers 5. FIG. 3 shows an example where the burners 1 are installed facing each other.

The shape of the flame is detected using the image fiber 5, and the flame shape to be detected is, for example, the stable base portion of the flame 2 including the tip of the burner 1, as shown in FIG.

Next, a stable part of the flame is a part where the time change rate of flame 2, which corresponds to fluctuation, does not exceed a preset value, or a part where the disturbance in the detected flame outline does not exceed a preset value. This includes areas where the value does not exceed the set value.

Taking advantage of the property that the shape of a flame becomes more stable the closer it gets to the root, a pre-memorized weighting function, as shown in Figure 5, is used for the shape of the flame or its changes near the root. By diagnosing, the diagnosis can be made more accurate. That is, for example, in FIG. 5, the preset limit value is used as the weighting coefficient and FIG.
) is used to determine whether the product of the P part exceeds a predetermined value. Weighting coefficient for WfdP, U is the upper limit, W
=PxW. Then, by calculating all the deviations between the flame patterns classified by characteristics and stored in advance and the flame patterns processed by the weighting coefficients of the detected flame patterns, the flame shape as the combustion state of the foiler is automatically determined. And it can be grasped quickly and accurately.

Furthermore, the same effects as the present invention can be obtained by using data obtained by statistically processing (for example, averaging) image signals. Additionally, an imaging device or infrared rays can be directly connected to the flame detection unit.
A similar effect can be obtained by installing a detection device such as ultraviolet light.

By implementing the present invention, the shape of the detected flame pattern can be monitored more accurately.

[Brief explanation of the drawing]

Fig. 1 shows an embodiment of the present invention, Fig. 2 shows a case where an image fiber is attached, Fig. 3 shows another embodiment of the invention, and Fig. 4 shows a flame root. FIG. 5 is a diagram showing the weighting process and the distance from the tip of the burner. 1... Burner, 2... Flame, 3... Heat exchanger tube, 4...
...Cooling device, 5... Image fiber, 6... Imaging device, 7... Furnace, 8... A/D converter, 9...
・Electronic computer, 10 brooms 7 figure 2 brooms 3 concave dormitory 4 figure no 5 eyes 11

Claims (1)

[Claims] 1. In a flame shape monitoring method, the shape of the base of the flame is memorized in advance, the deviation from the detected flame shape of the corresponding part is calculated and processed by a weighting function, and the processed flame shape is monitored. A flame shape monitoring method characterized by: