JP2019158268A - Abnormality determination method and abnormality determination device for oximeter installed in consecutive type heating furnace - Google Patents

Abstract

To provide an abnormality determination method and an abnormality determination device for oximeter installed in a continuous type heating furnace in which it is possible to determine an abnormal state when a response delay time of the oximeter is long and to control without making air ratio abnormal.SOLUTION: An abnormality determination method performed by an oximeter is carried out in such a way that at a correlation coefficient calculation step S5, a correlation coefficient Rcontinuously varying from the correlation coefficient Rat a first specified time T1 to a correlation coefficient Rat a second specified time T2 is calculated, at a response delay time calculation step S6, a response delay time of an oximeter 8 ranging from a first specified time T1 in which the oxygen concentration in the exhaust gas is measured by the oximeter 8 to a time in which the correlation coefficient Rthat is continuously changed reaches to the maximum value is calculated, at the abnormality determination steps S7 to S9, when the response delay time of the oximeter 8 is longer than a predetermined threshold value, it is determined that the oximeter 8 shows an abnormal state.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an abnormality determination method and an abnormality determination device for an oximeter installed in a continuous heating furnace.

  In a continuous heating furnace (hereinafter simply referred to as a heating furnace) in an ironworks, a byproduct gas is burned to heat a steel piece. As combustion control (combustion air amount control) of the heating furnace, the air ratio control for burning with a predetermined air ratio with respect to the amount of fuel gas used, and the oxygen concentration in the exhaust gas in the heating furnace to a constant value There are two types of exhaust gas oxygen concentration control. The exhaust gas oxygen concentration control is a control for keeping the air ratio low by setting the oxygen concentration in the exhaust gas in the heating furnace to a low value of 0.5 to 2.0% by volume. Generally, the oxygen concentration in the exhaust gas is expressed by the following formula.

Here, A ₀ represents the theoretical air amount, which means the amount of air that requires complete combustion with respect to a gas amount (G) of 1.0. G ₀ represents the theoretical exhaust gas amount, which means the exhaust gas amount generated when the gas amount (G) is 1.0 and the combustion air amount (A) is the theoretical air amount A ₀ . Further, m is air ratio, represented by m = the combustion air quantity A / theoretical air quantity A _0.
In steelworks, the oxygen concentration in the exhaust gas is not constant even when the air ratio is constant due to the use of gas types different from the theoretical air volume in the same heating furnace or the generation of air entering the heating furnace. . Furthermore, exhaust gas oxygen concentration control is used because the sensible heat (exhaust gas loss heat) brought out of the exhaust gas discharged outside the heating furnace can be estimated from the oxygen concentration in the exhaust gas in the heating furnace and the amount of fuel gas used. It is common.

Here, as what performs conventional exhaust gas oxygen concentration control, what is shown, for example in patent documents 1 thru / or 5 is known.
The inflammation control supplement method shown in Patent Document 1 is a combustion control method in which outside air can enter, and when the fuel flow rate supplied to the crater is equal to or higher than a set value, the air-fuel ratio is manipulated within a certain range, and the fuel flow rate is less than the set value. In this case, the oxygen concentration in the exhaust gas is controlled by adjusting the amount of intrusion air by operating the internal pressure of the combustion facility while keeping the air-fuel ratio in the above-mentioned fixed range.
Further, the continuous steel heating furnace shown in Patent Document 2 is based on an oxygen concentration detector that detects an oxygen concentration in an induced exhaust gas header pipe for each combustion control having a regenerative switching combustion burner, and a detection value of the oxygen concentration detector. And a control means for controlling the air ratio in the heating furnace.

Furthermore, in the operation method of the continuous heating furnace shown in Patent Document 3, a combustion burner that performs local heating is arranged at or near the inlet of the combustion zone located in the most downstream of the combustion exhaust gas flow in each combustion zone. The air ratio to the combustion burner is controlled so that the oxygen concentration in the combustion exhaust gas in the vicinity of the combustion burner becomes the target oxygen concentration.
Further, the combustion control method of the heating furnace shown in Patent Document 4 measures the unburned fuel concentration and the oxygen concentration in the exhaust, and based on these measured values, the fuel and air burner is supplied to the burner. The ratio of supply amount is adjusted.

  Moreover, the non-oxidative heating method of the direct-fired continuous heating furnace shown in Patent Document 5 is a heating atmosphere and a soaking zone in a reducing atmosphere with an air ratio of 1.0 or less in heating the steel material in the direct-fired continuous heating furnace. Combustion is performed, and in the pre-tropical zone, an air amount necessary for complete combustion calculated in advance based on the fuel flow rate and the unburned gas concentration in the heating zone and the soaking zone is supplied, and the pre-tropy is calculated based on the oxygen concentration in the exhaust gas from the furnace bottom The amount of air supplied to the tropics is adjusted.

Japanese Patent Publication No.58-43658 Japanese Patent No. 4653689 JP 2001-272028 A JP-A-9-280551 Japanese Patent Publication No.5-2725

Here, in any of these conventional techniques shown in Patent Documents 1 to 5, an oxygen concentration meter is installed in the heating furnace, and the exhaust gas oxygen concentration control is performed based on information obtained from the oxygen concentration meter. It is carried out.
However, any of the techniques disclosed in Patent Documents 1 to 5 has a problem that the amount of combustion air cannot be controlled when an abnormality occurs in the oximeter. In particular, in the case of a response delay of the oximeter, at first glance, an appropriate numerical value is displayed, and the person in charge of the furnace cannot notice that an abnormality has occurred. When a response delay occurs in the oximeter, the response of the oximeter is delayed even if the air ratio is changed due to the response delay, and as a result, the air ratio is greatly changed. As a result of changing the air ratio until the oxygen concentration becomes a value lower than the target value due to large fluctuations in the air ratio, there is a possibility that the combustion air becomes insufficient.

  Therefore, the present invention has been made to solve this conventional problem, and its purpose is to determine that the oxygen concentration meter installed in the heating furnace is abnormal when the response delay time is long, and the air ratio An object of the present invention is to provide an abnormality determination method and an abnormality determination device for an oximeter installed in a continuous heating furnace that can be controlled without making it abnormal.

In order to achieve the above object, an abnormality determination method for an oximeter installed in a continuous heating furnace according to one aspect of the present invention is an abnormality determination method for an oximeter installed in a continuous heating furnace. An oxygen concentration acquisition step for acquiring an oxygen concentration in exhaust gas in the continuous heating furnace continuously measured from the first specific time to a second specific time by the oxygen concentration meter; A fuel gas flow rate acquisition step of acquiring a fuel gas flow rate to a burner provided in the continuous heating furnace continuously measured from the first specific time to the second specific time by a gas flow meter; A combustion air flow rate acquisition step for acquiring a combustion air flow rate to the burner continuously measured from the first specific time to the second specific time by a combustion air flow meter, and the acquired combustion air flow rate And said ream An air ratio calculating step for calculating an air ratio that continuously changes from the first specific time to the second specific time based on the theoretical air amount used in the furnace, and the first specific The oxygen concentration in the exhaust gas at the time is an objective variable, and the multiple regression analysis is performed using the acquired fuel gas flow rate at the first specific time and the calculated air ratio at the first specific time as explanatory variables, Correlation coefficient R ² in the first specific time between the predicted oxygen concentration in the exhaust gas at the first specific time obtained as a result of the multiple regression analysis and the obtained oxygen concentration in the exhaust gas at the first specific time. is calculated, by performing the calculation of the correlation coefficient R ² continuously until the correlation coefficient R ² in the second specific time from the correlation coefficient R ² in the first specific time, changes continuously correlation A correlation coefficient calculation step of calculating the number R ^2, from the oxygen concentration of the first specified time of measuring the oxygen concentration in the exhaust gas by meter, the correlation coefficient R ² for continuously varying reaches the maximum value A response delay time calculating step of calculating a response delay time of the oximeter up to a time, and when the calculated response delay time of the oximeter is longer than a predetermined threshold, an abnormality of the oximeter The gist is to include an abnormality determination step for determination.

Further, an oxygen concentration meter abnormality determination device installed in a continuous heating furnace according to another aspect of the present invention is an oxygen concentration meter abnormality determination device installed in a continuous heating furnace, wherein the oxygen concentration meter abnormality determination device An oxygen concentration acquisition unit that acquires the oxygen concentration in the exhaust gas in the continuous heating furnace continuously measured from the first specific time to the second specific time by a densitometer; and the fuel gas flow meter A fuel gas flow rate acquisition unit for acquiring a flow rate of fuel gas to a burner provided in the continuous heating furnace continuously measured from a first specific time to the second specific time; and a combustion air flow meter The combustion air flow rate acquisition unit for acquiring the combustion air flow rate to the burner continuously measured from the first specific time to the second specific time, the acquired combustion air flow rate and the continuous heating The theoretical air volume used in the furnace and An air ratio calculation unit that calculates an air ratio that continuously changes from the first specific time to the second specific time, and an oxygen concentration in the exhaust gas at the first specific time as an objective variable, A multiple regression analysis is performed using the acquired fuel gas flow rate at the first specific time and the calculated air ratio at the first specific time as explanatory variables, and the first specific obtained as a result of the multiple regression analysis A correlation coefficient R ² at the first specific time between the predicted oxygen concentration in the exhaust gas at the time and the acquired oxygen concentration at the first specific time is calculated, and the correlation coefficient R ² is calculated. continuously performed until the correlation coefficient R ² in the second specific time from the correlation coefficient R ² in the first specific time, the correlation coefficient calculating for calculating a correlation coefficient R ² for continuously varying Part and the acid Wherein the first specific time of measurement of the oxygen concentration in the exhaust gas by oxygen concentration meter, the correlation coefficient R ² for continuously varying calculates the response delay time of the oxygen concentration meter up to the time to reach the maximum value A summary is provided with a response delay time calculation unit and an abnormality determination unit that determines that the oxygen concentration meter is abnormal when the calculated response delay time of the oxygen concentration meter is longer than a predetermined threshold. To do.

  According to the abnormality determination method and abnormality determination apparatus for the oxygen concentration meter installed in the continuous heating furnace according to the present invention, an abnormality occurs when the response delay time of the oxygen concentration meter installed in the continuous heating furnace is long. It is possible to provide an abnormality determination method and an abnormality determination device for an oximeter installed in a continuous heating furnace that can be controlled without making the air ratio abnormal.

It is a schematic block diagram of the abnormality determination apparatus of the oxygen concentration meter installed in the continuous heating furnace which concerns on one Embodiment of this invention. It is a flowchart which shows the flow of a process in the abnormality determination apparatus shown in FIG. It is a graph which shows an example of the fluctuation | variation data from 0 hours (1st specific time T1) of fuel gas flow volume and oxygen concentration to 35 hours (2nd specific time T2) in a continuous heating furnace. It is a graph which shows an example of the fluctuation | variation data from 0 hour (1st specific time T1) of air ratio and oxygen concentration to 35 hours (2nd specific time T2) in a continuous heating furnace. Is a graph showing an example of a correlation coefficient R ² for continuously varying calculated by the correlation coefficient calculating unit. Is a graph showing an example of a correlation coefficient R ² for continuously changes that correct response delay time period.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following embodiments exemplify apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention is based on the material, shape, structure, arrangement, etc. of components. It is not specified in the following embodiment. The drawings are schematic. For this reason, it should be noted that the relationship between the thickness and the planar dimension, the ratio, and the like are different from the actual ones, and the dimensional relationship and the ratio are different between the drawings.

FIG. 1 shows a schematic configuration of an abnormality determination device for an oximeter installed in a continuous heating furnace according to an embodiment of the present invention. A continuous heating furnace (hereinafter simply referred to as a heating furnace) 1 includes a heating furnace body 2 that heats a material to be heated S to a predetermined temperature. A charging door 3 is provided on the side of the heating furnace body 2 where the material to be heated S is charged, and an extraction door 4 is provided on the side of the heating furnace body 2 where the material to be heated S is extracted. The material to be heated S is heated to a predetermined temperature while being transported by the skid 12 from the charging side with the charging door 3 to the extraction side with the extraction door 4.
A flue 11 is provided in the vicinity of the charging side end of the heating furnace body 2, and the flue gas is exchanged by the recuperator 7 provided in the middle of the flue 11 from the flue 11. It is supposed to be discharged.

A regenerative burner 5 for heating the material to be heated S is provided in the vicinity of the flue 11 in the heating furnace main body 2, and a predetermined pitch is provided in the heating furnace main body 2 from the charging side to the extraction side. A plurality of burners 6 are provided. Each burner 6 also heats the material to be heated S.
Here, fuel gas is introduced into the regenerative burner 5 from the fuel gas supply source 10 through the fuel gas flow meter 52, and combustion is performed from the combustion air supply source 54 through the combustion air flow meter 53 and the heat storage body 51. Air is introduced. The regenerative burner 5 burns with the introduced fuel gas and combustion air, and the combusted exhaust gas is discharged to the chimney 9 via the heat accumulator 51 and the exhaust gas flow meter 55. Here, the code | symbol 56 is the suction blower provided in exhaust gas piping.

In addition, fuel gas is introduced into each burner 6 from a fuel gas supply source 10 via a fuel gas flow meter 61, and the combustion air heat-exchanged by the recuperator 7 installed in the flue 11 is the combustion air flow rate. It is introduced via the total 62. Each burner 6 burns with the introduced fuel gas and combustion air, and the burned exhaust gas is discharged from the flue 11. Here, reference numeral 71 is a hot air thermometer, and 73 is a suction blower.
An oxygen concentration meter 8 for measuring the oxygen concentration in the exhaust gas is installed near the entrance of the flue 11 of the heating furnace body 2 and on the ceiling of the heating furnace body 2.

As shown in FIG. 3, the oxygen concentration meter 8 changes the oxygen concentration in the exhaust gas in the heating furnace main body 2 from 0 hour (first specific time T1) to 35 hours (second specific time T2). Measure continuously.
Further, the fuel gas flow meter 52 for the regenerative burner 5 and the fuel gas flow meter 61 for each burner 6 are respectively introduced into the burner 6 as shown in FIG. The fuel gas flow rate is continuously measured from 0 hour (first specific time T1) to 35 hours (second specific time T2).

Here, the fluctuation data of the oxygen concentration in the exhaust gas measured by the oxygen concentration meter 8 and the fuel gas flow rate measured by the fuel gas flow meter 52 for the regeneration burner 5 and the fuel gas flow meter 61 for each burner 6 are shown. The relationship with the fluctuation data will be seen from FIG. 3 (an example of fluctuation data is shown). The fluctuation data of the oxygen concentration in the exhaust gas measured by the oxygen concentration meter 8 cannot be clearly seen with respect to the fluctuation data of the fuel gas flow rate, but is slightly delayed.
Further, the combustion air flow meter 53 for the regenerative burner 5 and the combustion air flow meter 62 for each burner 6 respectively calculate the combustion air flow rate introduced into the regenerative burner 5 and the combustion air flow rate introduced into each burner 6. Measurement is continuously performed from 0 hour (first specific time T1) to 35 hours (second specific time T2).

  Here, the fluctuation data of the oxygen concentration in the exhaust gas measured by the oxygen concentration meter 8 and the combustion air flow rate measured by the combustion air flow meter 53 for the regeneration burner 5 and the combustion air flow meter 62 for each burner 6 are obtained. The relationship with the fluctuation data of the air ratio calculated based on the above will be seen from FIG. 4 (an example of fluctuation data is shown). The fluctuation data of the oxygen concentration in the exhaust gas measured by the oxygen concentration meter 8 is calculated based on the combustion air flow rate measured by the combustion air flow meter 53 for the regeneration burner 5 and the combustion air flow meter 62 for each burner 6. The response time delay can be clearly seen for the air ratio fluctuation data.

Therefore, in the present embodiment, the response delay time of the oximeter 8 is calculated using the fuel gas flow rate and the air ratio as parameters, and the oxygen concentration is determined in order to determine that there is an abnormality when the response delay time is long. A total of eight abnormality determination devices 20 are provided.
Here, as shown in FIG. 1, the abnormality determination device 20 includes an oxygen concentration meter 8, a fuel gas flow meter 52 for the regeneration burner 5, a fuel gas flow meter 61 for each burner 6, and combustion air for the regeneration burner 5. The flowmeter 53 and the combustion air flowmeter 62 for each burner 6 are connected.
This abnormality determination device 20 determines abnormality when the response delay time of the oximeter 8 is long, and includes an oxygen concentration acquisition unit 21, a fuel gas flow rate acquisition unit 22, a combustion air flow rate acquisition unit 23, and an air ratio calculation unit. 24, a correlation coefficient calculation unit 25, a response delay time calculation unit 26, and an abnormality determination unit 27.

The abnormality determination device 20 includes an oxygen concentration acquisition unit 21, a fuel gas flow rate acquisition unit 22, a combustion air flow rate acquisition unit 23, an air ratio calculation unit 24, a correlation coefficient calculation unit 25, a response delay time calculation unit 26, and an abnormality determination unit 27. It is a computer system which has the arithmetic processing function for implement | achieving each of these functions by running a program on computer software. The computer system includes a ROM, a RAM, a CPU, and the like, and implements the functions described above on software by executing various dedicated programs stored in advance in the ROM.
Here, the oxygen concentration acquisition unit 21 of the abnormality determination device 20 is connected to the oxygen concentration meter 8, and the oxygen concentration meter 8 changes the first specific time T1 (0 hour) to the second specific time T2 (35 hours). The oxygen concentration in the exhaust gas in the heating furnace main body 2 measured continuously is obtained.

The fuel gas flow rate acquisition unit 22 is connected to the fuel gas flow meter 52 for the regeneration burner 5 and the fuel gas flow meter 61 for each burner 6, and the fuel gas flow meters 52 and 61 use the first specific time T 1 ( The fuel gas flow rate continuously measured from 0 hour) to the second specific time (35 hours) T2 is acquired.
Further, the combustion air flow rate acquisition unit 23 uses the combustion air flow meter 53 for the regenerative burner 5 and the combustion air flow meter 62 for each burner 6 from the first specific time T1 (0 hour) to the second specific time T2 ( 35 hours), the amount of combustion air to the regeneration burner 5 and the burner 6 measured continuously is acquired.
In addition, the air ratio calculation unit 24 calculates the first specific time T1 (0 hour) to the second from the combustion air flow rate acquired from the combustion air flow rate acquisition unit 23 and the theoretical air amount used in the heating furnace body 2. The air ratio that continuously changes until the specific time T2 (35 hours) is calculated.

Then, the correlation coefficient calculation unit 25 uses the oxygen concentration in the exhaust gas at the first specific time T1 (0 hour) as an objective variable, and the first specific time T1 (0 hour) acquired by the fuel gas flow rate acquisition unit 22 ) And the air ratio at the first specific time T1 (0 hour) calculated by the air ratio calculation unit 24 in FIG.
y = a ₁ x ₁ + a ₂ x ₂ + b (1)
Here, y is a predicted concentration which is a predicted value of the oxygen concentration in the exhaust gas in the heating furnace body 2, x _{1 is an} air ratio, x _{2 is a} fuel gas flow rate, and b is a constant term.

Further, the correlation coefficient calculation unit 25 uses the predicted oxygen concentration y in the exhaust gas at the first specific time T1 (0 hour) obtained as a result of the multiple regression analysis, and the first specific acquired by the oxygen concentration acquisition unit 21. A correlation coefficient R ² (also referred to as a multiple determination coefficient) at the first specific time T1 (0 hour) with the oxygen concentration (measured oxygen concentration) in the exhaust gas at the time T1 (0 hour) is calculated.
Moreover, the correlation coefficient calculation unit 25, a correlation coefficient at the correlation coefficient ^R to calculate the ² first specific time T1 from the correlation coefficient ^{R 2} in (0 hours) the second specific time T2 (35 hours) By continuously performing up to R ² , a continuously changing correlation coefficient R ² is calculated.

That is, the correlation coefficient calculation unit 25, while shifting little by little until (1) y and _{x 1} and _{x 2} of the time the first specific time T1 (0 hours) from the second specific time in the formula (35 hours) The multiple regression analysis is performed many times, and each time the correlation coefficient R ² is calculated, the continuously changing correlation coefficient R ² is calculated.
An example of a correlation coefficient R ² for continuously varying calculated by the correlation coefficient calculation unit 25 shown in FIG.
Referring to FIG. 5, the correlation coefficient R ² continuously changes from the first specific time T1 (0 hours) when the oxygen concentration in the exhaust gas is measured by the oximeter 8. the correlation coefficient ^{R 2} is the maximum value after 49 minutes from a specific time T1 (0 h) (DT).

Accordingly, the response delay time calculating unit 26, a first specific time T1 (0 hours) Time to a maximum value correlation coefficient R ² from DT (after 49 minutes of measurement of the oxygen concentration in the exhaust gas by the oxygen concentration meter 8 The response delay time of the oximeter 8 is calculated.
The abnormality determining unit 27 determines that the oximeter 8 is abnormal when the response delay time calculated by the response delay time calculating unit 26 is longer than a predetermined threshold. This threshold value is determined from past results, and is, for example, about 0 to 5 minutes.
Here, in the example shown in FIG. 5, since the response delay time 49 minutes is longer than the threshold value (0 to 5 minutes), the oximeter 8 is determined to be abnormal.

A display device 30 is connected to the abnormality determination unit 27 of the abnormality determination device 20. The display device 30 is constituted by an output device such as a printer, and displays the response delay time described above when the abnormality determination unit 27 determines that the oximeter 8 is abnormal.
Incidentally, it 5, the correlation coefficient R ² in the first specific time T1 was measured oxygen concentration in the exhaust gas by the oxygen concentration meter 8 (0 hours) have been a 0.0035, and most uncorrelated and which is, when considering the response delay time 49 minutes, a correlation coefficient R ² can be considered 0.435 (maximum value), and a certain correlation.

Therefore, when correcting the response delay time 49 minutes oximeter 8, a correlation coefficient R ² for continuously varying is as shown in FIG. 6, after corrective where hardly a response delay time, the phase relationship number R ² is to have the maximum value.
For this reason, by controlling the oxygen concentration meter 8 so as to be faster by the response delay time, it is possible to control the oxygen concentration in the exhaust gas with almost no response delay time.

Next, the flow of processing in the abnormality determination device 20 will be described with reference to FIG.
The oxygen concentration acquisition unit 21 of the abnormality determination device 20 executes the following step S1 that is an oxygen concentration acquisition step. Further, the fuel gas flow rate acquisition unit 22 executes Step S2 which is a fuel gas flow rate acquisition step. The combustion air flow rate acquisition unit 23 executes step S3 which is a combustion air flow rate acquisition step, and the air ratio calculation unit 24 executes step S4 which is an air ratio calculation step. Further, the correlation coefficient calculation unit 25 executes step S5 which is a correlation coefficient calculation step, the response delay time calculation unit 26 executes step S6 which is a response delay calculation step, and the abnormality determination unit 27 Steps S7 to S9, which are determination steps, are executed.

First, in step S1, the oxygen concentration acquisition unit 21 continuously measures the heating furnace from the first specific time T1 (0 hour) to the second specific time T2 (35 hours) by the oxygen concentration meter 8. The oxygen concentration in the exhaust gas in the main body 2 is acquired.
Next, in step S2, the fuel gas flow rate acquisition unit 22 continuously measures from the first specific time T1 (0 hour) to the second specific time (35 hours) T2 by the fuel gas flow meters 52 and 61. The obtained fuel gas flow rate is acquired.
Further, in step S3, the combustion air flow rate acquisition unit 23 performs the second operation from the first specific time T1 (0 hour) using the combustion air flow meter 53 for the regeneration burner 5 and the combustion air flow meter 62 for each burner 6. The combustion air amount to the regeneration burner 5 and the burner 6 continuously measured until the specific time T2 (35 hours) is acquired.

In step S4, the air ratio calculation unit 24 calculates the first specific time T1 (0 hours) from the combustion air flow rate acquired from the combustion air flow rate acquisition unit 23 and the theoretical air amount used in the heating furnace body 2. To the second specific time T2 (35 hours) is calculated.
Next, in step S5, the correlation coefficient calculation unit 25 uses the oxygen concentration in the exhaust gas at the first specific time T1 (0 hour) as an objective variable, and the first specific time acquired by the fuel gas flow rate acquisition unit 22 The multiple regression analysis is performed by the above equation (1) using the fuel gas flow rate at T1 (0 hour) and the air ratio at the first specific time T1 (0 hour) calculated by the air ratio calculation unit 24 as an explanatory variable. The predicted oxygen concentration y in the exhaust gas at the first specific time T1 (0 hour) obtained as a result of the regression analysis, and the oxygen in the exhaust gas at the first specific time T1 (0 hour) acquired by the oxygen concentration acquisition unit 21 calculating a correlation coefficient R ² in a concentration first specific time T1 (the actually measured oxygen concentrations) (0 hours).

Further, in step S5, the correlation coefficient calculation unit 25, the second specific time T2 (35 hours) from the correlation coefficient ^{R 2} in the calculation of the correlation coefficient ^{R 2} first specific time T1 (0 hours) continuously performed until the correlation coefficient R ² in the calculates a correlation coefficient R ² for continuously varying.
Then, in step S6, the response delay time calculating unit 26, an oxygen concentration meter 8 times the first correlation coefficient R ² from a certain time T1 (0 h) was measured oxygen concentration in the exhaust gas to a maximum value by DT The response delay time of the oxygen concentration meter 8 is calculated.
Then, in step S7, the abnormality determination unit 27 determines whether or not the response delay time calculated by the response delay time calculation unit 26 is longer than a predetermined threshold. If the response delay time is longer (YES), the process proceeds to step S8. If it is the same or shorter (NO), the process ends.

The abnormality determination unit 27 recognizes the abnormality determination in step S8, outputs the response delay time calculated in step S6 to the display device 30 in step S9, and ends the process.
Thus, according to the abnormality determination method and the abnormality determination apparatus for an oxygen concentration meter provided on the continuous heating furnace according to the present embodiment, the second identified from the correlation coefficient R ² in the first specific time T1 A correlation coefficient R ² that continuously changes up to the correlation coefficient R ² at time T ² is calculated, and a phase that changes continuously from the first specific time T 1 when the oxygen concentration in the exhaust gas is measured by the oxygen concentration meter 8. If correlation coefficient R ² calculates the oximeter 8 response delay time up to the time to reach the maximum value, the response delay time of the oxygen concentration meter 8, which is calculated is longer than the predetermined threshold value, the oxygen concentration meter 8 Judged as abnormal.

As a result, when the response delay time of the oxygen concentration meter 8 installed in the continuous heating furnace 1 is long, it is determined that there is an abnormality, and even when an unavoidable response time delay occurs in the oxygen concentration meter 8, the air ratio is abnormal. It is possible to control the oxygen concentration in the exhaust gas without making it.
Further, when it is determined that the oximeter 8 is abnormal, the calculated response delay time of the oximeter 8 is output to the display device 30, and the display device 30 displays the response delay time. However, the abnormality of the oximeter 8 can be quickly detected by looking at the display device 30.
The person in charge of the furnace can quickly correct the response delay time of the oximeter 8.

As mentioned above, although embodiment of this invention has been described, this invention is not limited to this, A various change and improvement can be performed.
For example, in the measurement by the oxygen concentration meter 8, the measurement by the fuel gas flow meters 52 and 61, and the measurement by the combustion air flow meters 53 and 62, the first specific time T1 is 0 hour, and the second specific time T2 is 35 hours. However, these times can be set arbitrarily.

DESCRIPTION OF SYMBOLS 1 Continuous heating furnace 2 Heating furnace main body 3 Loading door 4 Extraction door 5 Regenerative burner 6 Burner 7 Recuperator 8 Oxygen meter 9 Chimney 10 Fuel gas supply source 11 Flue 12 Skid 20 Abnormality judgment device 21 Oxygen concentration acquisition part 22 Fuel Gas flow rate acquisition unit 23 Combustion air flow rate acquisition unit 24 Air ratio calculation unit 25 Correlation coefficient calculation unit 26 Response delay time calculation unit 27 Abnormality determination unit 30 Display device 51 Heat storage body 52 Fuel gas flow meter 53 Combustion air flow meter 54 Combustion air Supply source 55 Exhaust gas flow meter 56 Suction blower 61 Fuel gas flow meter 62 Combustion air flow meter 71 Hot air thermometer 72 Suction blower S Heated material T1 First specific time T2 Second specific time

Claims (4)

An oxygen concentration meter abnormality determination method installed in a continuous heating furnace,
An oxygen concentration acquisition step of acquiring the oxygen concentration in the exhaust gas in the continuous heating furnace continuously measured from the first specific time to the second specific time by the oxygen concentration meter;
A fuel gas flow rate acquisition step of acquiring a fuel gas flow rate to a burner provided in the continuous heating furnace, which is continuously measured from the first specific time to the second specific time by a fuel gas flow meter When,
A combustion air flow rate acquisition step of acquiring a combustion air amount to the burner continuously measured from the first specific time to the second specific time by a combustion air flow meter;
Air ratio calculation for calculating an air ratio that continuously changes from the first specific time to the second specific time from the obtained combustion air flow rate and the theoretical air amount used in the continuous heating furnace. Steps,
The oxygen concentration in the exhaust gas at the first specific time is used as an objective variable, and the obtained fuel gas flow rate at the first specific time and the calculated air ratio at the first specific time are used as explanatory variables. A regression analysis is performed, and the predicted oxygen concentration in the exhaust gas at the first specific time obtained as a result of the multiple regression analysis and the obtained oxygen concentration in the exhaust gas at the first specific time at the first specific time calculating a correlation coefficient R ^2, performs calculation of the correlation coefficient R ² to the continuously until the correlation coefficient R ² in the second specific time from the correlation coefficient R ² in the first specific time, A correlation coefficient calculating step for calculating a continuously changing correlation coefficient R ² ;
From the oxygen concentration of the first specified time of measuring the oxygen concentration in the exhaust gas by meter, calculating the response delay time of the oxygen concentration meter up to the time that the correlation coefficient R ² for continuously varying reaches the maximum value A response delay time calculating step,
And an abnormality determining step for determining that the oxygen concentration meter is abnormal when the calculated response delay time of the oxygen concentration meter is longer than a predetermined threshold value. Oxygen meter abnormality judgment method.   When it is determined in the abnormality determination step that the oximeter is abnormal, the calculated response delay time of the oximeter is output to a display device, and the display device displays the response delay time. An abnormality determination method for an oxygen concentration meter installed in a continuous heating furnace according to claim 1, comprising: An oxygen concentration meter abnormality determination device installed in a continuous heating furnace,
An oxygen concentration acquisition unit for acquiring the oxygen concentration in the exhaust gas in the continuous heating furnace continuously measured from the first specific time to the second specific time by the oxygen concentration meter;
A fuel gas flow rate acquisition unit for acquiring a fuel gas flow rate to a burner provided in the continuous heating furnace continuously measured from the first specific time to the second specific time by a fuel gas flow meter When,
A combustion air flow rate acquisition unit for acquiring a combustion air amount to the burner continuously measured from the first specific time to the second specific time by a combustion air flow meter;
Air ratio calculation for calculating an air ratio that continuously changes from the first specific time to the second specific time from the obtained combustion air flow rate and the theoretical air amount used in the continuous heating furnace. And
The oxygen concentration in the exhaust gas at the first specific time is used as an objective variable, and the obtained fuel gas flow rate at the first specific time and the calculated air ratio at the first specific time are used as explanatory variables. A regression analysis is performed, and the predicted oxygen concentration in the exhaust gas at the first specific time obtained as a result of the multiple regression analysis and the obtained oxygen concentration in the exhaust gas at the first specific time at the first specific time calculating a correlation coefficient R ^2, performs calculation of the correlation coefficient R ² to the continuously until the correlation coefficient R ² in the second specific time from the correlation coefficient R ² in the first specific time, A correlation coefficient calculating unit for calculating a continuously changing correlation coefficient R ² ;
From the oxygen concentration of the first specified time of measuring the oxygen concentration in the exhaust gas by meter, calculating the response delay time of the oxygen concentration meter up to the time that the correlation coefficient R ² for continuously varying reaches the maximum value A response delay time calculating unit,
In the continuous heating furnace, comprising: an abnormality determination unit that determines that the oxygen concentration meter is abnormal when the calculated response delay time of the oxygen concentration meter is longer than a predetermined threshold value. An abnormality determination device for the installed oxygen concentration meter.   The apparatus according to claim 3, further comprising a display device that displays the response delay time when the abnormality determination unit determines that the oximeter is abnormal. Oxygen meter abnormality determination device.

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