KR980009427A - Method and Apparatus for Managing Combustion Waste Gas in a Coke Oven - Google Patents

Abstract

The present invention relates to a method and an apparatus for managing waste combustion gas in a coke oven. More specifically, when the third switch 40 is turned on, the second switch 39 and the first switch 38 are automatically turned off When the waste gas component is detected by the concentration detector 34 and transmitted to the primary comparator 36 through the signal converter 35 when the waste gas component is off and on, The operation of the signal generator 25, the hydraulic pressure regulator 26, and the smoke reduction damper 2 until they become the same; The first reset signal generator 28 and the second memory device 30 are operated while the hydraulic pressure regulator 26 and the smoke reduction damper 2 are stopped by the operation stop signal generator 27 when the supply gas is replaced, Determining whether oxygen concentration control or negative pressure management is performed by the second storage device (30); The second switch 39 and the third switch 40 are turned on and off by the second reset signal generator 32 to be switched to the initial negative pressure state, The second switch 39 and the third switch 40 are turned off by the reset operation of the set value of the first storage device 31 and the re-operation of the second reset signal generator 32, ), Turning on (turning on) the waste gas oxygen concentration control; The first, second, and third switches 38, 39, and 40 are automatically turned off, turned on, and off when disturbance occurs in the disturbance generating memory device 33 during oxygen concentration control, The comparator 23 switches the first, second and third switches 38, 39 and 40 to the automatic off state, the on state and the off state, respectively, by the signal of the negative pressure detector 21, And controlling the oil pressure regulator (26) and the small-sized smoke filter (2) until the oil is turned off, and switching to oxygen concentration management. The method for managing combustion exhaust gas of a coke oven according to claim 1, A waste gas component analyzer 50 for detecting a waste gas component of the waste gas; A waste gas oxygen concentration detector 34 for detecting the oxygen concentration in the waste gas detected by the waste gas component analyzer 50; A concentration converter (35) for converting the oxygen concentration detected by the waste gas oxygen concentration detector (34) into an oxygen concentration signal; The signal transmitted from the concentration converter 35 is compared with the set value of the concentration set value storage device 37 and sent to the signal generator 25 by turning off the second switch 39, (36) connected to the operation stop signal generator (27) by the ON state of the operation stop signal generator (40); A second memory device (30) for receiving the oxygen concentration control signal of the operation stop signal generator (27) through the first reset signal generator (28) and determining the current operation state; A second reset signal generator 32 which is operated by the first and second storage devices 31 and 30 and operates the second and third switches 39 and 40 to switch the current operation state to oxygen concentration control or negative pressure management, Wow; The first, second and third switches 38, 39 and 40 are operated when disturbance occurs during the oxygen concentration control while being connected to the concentration set value storage device 37 by the ON switch of the first switch 38, And a disturbance generation storage device (33) for switching the oxygen concentration control. [Means for Solving the Problem] The present invention relates to a combustion waste gas management device for a coke oven.

Description

Method and Apparatus for Managing Combustion Waste Gas in a Coke Oven

More particularly, the present invention relates to a method and an apparatus for managing waste combustion gas in a coke oven. More particularly, the present invention relates to an indirect heating (1000 to 1300 ° C) To 18 hours). By analyzing the combustion waste gas generated in the process of manufacturing coke, the oxygen concentration control using the oxygen concentration in the waste gas and the management of the negative pressure of the waste gas complement each other. The oxygen concentration in the waste gas And more particularly, to a method and an apparatus for managing coke oven combustion waste gas that can be automatically managed.

Generally, as shown in FIG. 1, when the combustion air (8) of the combustion chamber is excessively introduced according to the degree of negative pressure in the combustion chamber (1) after combustion in the combustion chamber (6) of the coke oven, Even if the inflow is small, incomplete combustion reduces combustion efficiency, and carbon monoxide is discharged to the stack (4), which causes environmental pollution.

In addition, when the lowering of the combustion efficiency of the combustion chamber (6) results in severe undulation of the furnace, it affects the service life of the furnace.

In this way, the method and apparatus for controlling the negative pressure of the waste gas after combustion in the coke oven are most important in the installation management.

On the other hand, due to the nature of the coke oven, the combustion method is divided into an even number and an odd number of combustion chambers, and the supply and shutoff of the mixture gas is regularly repeated in a cycle of 20 to 30 minutes. The even number combustion chamber is composed of 37 rows (FULE) Each combustion chamber is composed of 32 individual combustion chambers, and two individual combustion chambers form a pair to serve as combustion and waste gas discharge passages. The waste gas discharged from the combustion chambers collects into a waste gas discharge passage in the lower portion of the combustion chamber. (3), (5), and (4) through the two small combustion stages (1) through the waste gas disposal side of the waste gas stream Four buffers (2) are installed in the inside of the subsoil, and a constant negative pressure is maintained by repeating the opening and closing by the hydraulic device in order to keep the internal negative pressure of the subsoil constant.

By adjusting the negative pressure, it is possible to keep the positive pressure in the combustion chamber constant by discharging a certain amount of the combustion waste gas in the combustion chamber 6, thereby preventing the unnecessary intake of air and uniformly maintaining the combustion thermal efficiency. Can be maintained.

That is, the total combustion process of the coke oven is performed by using the negative pressure generated by the natural ventilation force of the stack 4, so that the burden 2 of the two small boilers 1 is repeatedly opened and closed by the hydraulic device, Therefore, the amount of combustion gas is regulated to control the combustion chamber combustion condition and the combustion condition.

This method of managing the negative pressure of the waste gas after combustion in a coke oven can be said to be effective in a continuous combustion furnace in a single combustion chamber or in a furnace where the internal temperature of the combustion chamber is kept constant. However, It is considered that there is a weak point in terms of combustion thermal efficiency and air ratio management in a specific large-sized furnace in which gas replacement is repeatedly performed and cooling and heating are repeated in the combustion chamber internal furnace.

That is, when combustion gas and air are supplied to the even combustion chamber in each combustion chamber row (FLUE), the odd combustion chamber becomes the exhaust passage of the burned off gas in the even combustion chamber and conversely the combustion gas and air The even combustion chamber becomes a waste gas discharge passage.

Therefore, in the combustion chamber where the supply gas is exchanged, the internal temperature of the combustion chamber becomes shorter as time elapses after the gas is replaced, and the temperature of the waste gas increases as the temperature of the combustion chamber increases over time.

The temperature rise of the waste gas leads to the increase of natural ventilation of the stack (4), but it also controls the combustion condition of the entire combustion. (1) The waste gas negative pressure management keeps constant constant by continuously comparing and measuring internal negative pressure. When the exhaust gas volume of the combustion chamber 6 increases and the amount of the waste gas due to the increase of the temperature of the combustion gas in the combustion chamber 6 is expanded to reach the waste gas discharge limit, the supply gas 9 is positive pressure blowing, The oxygen concentration in the waste gas is lowered as the combustion progresses and the incomplete combustion is generated. Further, due to the change in the operation rate and the change in the combustion amount of the combustion gas in the combustion chamber when the amount of heat and flow rate of the combustion- Since the concentration varies, the internal negative pressure must be adjusted by the driver at all times. Therefore, A constant range deviation occurs.

Also, in order to prevent this, the internal pressure of the small burner is controlled to be high to control the oxygen concentration in the waste gas, but the combustion efficiency is lowered and the environmental pollutant (NOx) is increased.

In this way, the method and apparatus for managing the negative pressure of the waste gas after combustion in the combustion chamber of the coke oven have a great influence on the temperature and the combustion condition according to the minute negative pressure change, while the simple negative pressure control is performed. There has been a demand for coping.

Conventionally, the air supplied to the combustion chamber 6 through the combustion air inflow passage 8 and the air supplied to the gas mixture pipe 10 are mixed with each other to heat the coal charged through the entry port into the sealed coke oven carbonization chamber to produce coke. The gas generated in the combustion chamber 6 is supplied to the oven carburetor chamber 7 through the mixed gas passage 9 and the waste gas in the waste gas combustion chamber 6, And is discharged to the atmosphere through the waste side 5, the small side 1, the small side 2, the middle side 3, The entire combustion state of the combustion process is controlled by the negative pressure generated by the natural ventilation force of the stack 4 so that the dummy 2 installed in the two small scrubbers 1 is opened and closed by the hydraulic device, The combustion state is controlled by operating the internal negative pressure uniformly and discharging a certain amount of waste gas.

In addition, the combustion state of the combustion gas mixture is entirely changed when the calorimeter 43 and the flow rate controller 45 are adjusted. Therefore, the internal pressure of the combustion chamber 1 is adjusted by the driver to adjust the combustion state.

In order to maintain the internal negative pressure constant, the negative pressure detector 21 detects the internal negative pressure in the small-scale valve 1, and the negative pressure signal is transmitted to the signal generator 25 in the secondary comparator 23, A negative pressure is detected in the negative pressure detector 21 in which the small-sized duct 2 is operated by the operation of the hydraulic pressure regulator 26 by a signal instructed by the signal instructed to the negative pressure detector 25 and the pressure tube is inserted into the small- .

The measured negative pressure detected at this time is measured by the negative pressure set value set in the negative pressure set value storage unit 24. The signal detected from the negative pressure detector 21 is converted by the signal converter 22 and input to the comparator 23 The negative pressure is continuously adjusted until it becomes equal to the negative pressure set value inputted to the negative pressure set value storage device 24. [

In addition, since supply gas is regularly supplied and cut off in a cycle of 20 to 30 minutes to each row of the combustion chambers 6, when an external gas shutoff signal is received at the time of replacing the gas and is transmitted to the operation stop signal generator 27, 27 instructs the hydraulic pressure regulator 26 to stop the negative pressure in the small duct 1 and stop the operation of the small duct 2 so that the first storage device 31 is operated by the external gas supply signal (1) The signal from the internal negative pressure detector 21 causes the comparator 23 to compare the negative pressure and instructs the signal generator 25 to compare the negative pressure.

At this time, the signal generator 25 issues a readjustment instruction to the small-sized water tank 2 through the oil pressure regulator 26 and repeats the above-mentioned operation.

However, in the conventional apparatus as described above, since the negative pressure in the small-sized furnace 1 is kept constant, the supply of the mixed gas to the combustion chamber rows is regularly changed due to the characteristics of the furnace, so that the temperature in the combustion chamber 6 increases, Thus, the oxygen concentration in the waste gas is lowered due to restriction of inflow of combustion air due to natural ventilation, so that the countermeasure against incomplete combustion occurrence is not achieved.

That is, even when the change of the ventilation force and the gas volume in the combustion chamber 6 are changed by the influence of the combustion gas temperature according to the ideal gas-phase equation principle and the outside air temperature at the upper part of the stack, the negative pressure is kept constant, And the factor of the change is that the inflow of the combustion air due to the natural ventilation force is limited, so that the combustion proceeds and the oxygen concentration in the waste gas is lowered.

Further, since the combustion chamber combustion state is changed and the oxygen concentration in the waste gas is changed when the calorific value control system 43 and the flow rate control system 45 of the combustion gas supply gas are adjusted, the negative pressure setting value 24 is arbitrarily set by the driver The deviation of each driver is generated and the combustion state is also changed, thereby causing an increase in heat loss and incomplete combustion.

In the present invention, a waste gas component analyzer is installed in a small-sized furnace to detect the oxygen concentration by analyzing components in the waste gas so that the opening and closing of the spout is controlled in accordance with the oxygen concentration change in the waste gas, The amount of oxygen in the waste gas is kept constant, so that excessive combustion of the combustion air can be prevented, and incomplete combustion due to the shortage of the combustion air can be prevented, so that the coke oven And a method and an apparatus for managing waste combustion gas.

FIG. 1 is a flow diagram of a method and apparatus for managing waste combustion gas in a coke oven according to the prior art; FIG.

FIG. 2 is a flow diagram of a method and an apparatus for managing waste combustion gas in a coke oven according to the present invention.

Description of reference numerals used in the main parts of the drawings

1: So-Yeon-Do 2:

3: medium degree 4: stack

5: waste side 6: combustion chamber

21: negative pressure detector 24: negative pressure set value storage device

27: Operation stop signal generator 28: First reset signal generator

30: second storage device 31: first storage device

32: second reset signal generator 33: disturbance occurrence storage device

34: waste gas oxygen concentration detector 37: concentration setting memory

38: first switch 39: second switch

40: third switch 43: supply gas calorimeter

45: Supply gas flow rate controller 50: Combustion gas component analyzer

In order to achieve the above object, according to the present invention, an internal negative pressure of a small smoke level detected by a negative pressure detector is converted into a signal from a signal converter and input to the comparator, until a negative pressure set value of the negative pressure set value storage device becomes equal to a negative pressure set value. The second switch and the first switch are automatically turned off and on when the third switch is turned on in the negative pressure management method of the coke oven waste gas in which the negative pressure is adjusted by the hydraulic regulator, The process of operating the signal generator, the hydraulic regulator, and the small-sized hydrator until the waste gas component is detected by the concentration detector and transmitted to the primary comparator through the signal converter until it becomes equal to the set value of the oxygen concentration setpoint storage device; The first reset signal generator and the second memory device are operated while the hydraulic regulator and the smoke reduction damper are stopped by the operation stop signal generator when the supply gas is replaced and the oxygen concentration control or the negative pressure management is discriminated by the second memory device and; In the case of oxygen concentration control, the second reset signal generator turns on and off the second switch and the third switch, respectively, and is switched to an initial negative pressure state, The second switch and the third switch are turned off and turned on by the operation of the set value operation of the first reset signal generator and the re-operation of the second reset signal generator, respectively, to switch to the waste gas oxygen concentration control; The first, second, and third switches are automatically turned off, turned on, and off when the disturbance occurs in the disturbance generating storage device during the oxygen concentration control, The comparator controls the oil pressure regulator and the small-volume doser to switch to the oxygen concentration control until the first, second and third switches are automatically turned on, off, and turned on, respectively The method for managing waste combustion gas in a coke oven according to the present invention comprises the steps of:

Further, the present invention provides a vacuum cleaner comprising: a negative pressure detector installed to detect an internal negative pressure of a small duct; A signal converter for converting the negative pressure detected by the negative pressure detector into a signal; A comparator for comparing the signal transmitted from the signal converter with a set value of the negative pressure set value storage device and sending the signal to the negative pressure signal generator; A hydraulic pressure regulator for receiving a signal from the negative pressure signal generator and operating a soot damper; An operation stop signal generator for receiving a signal from the comparator and the hydraulic pressure regulator and sending a signal to the hydraulic cylinder again; And a first storage device for sending a set value to the negative pressure setpoint storage device by an external gas supply signal, the apparatus comprising: a waste gas component analyzer for detecting a waste gas component of the smoke diagram; A waste gas oxygen concentration detector for detecting the oxygen concentration in the waste gas detected by the waste gas analyzer; A concentration converter for converting the oxygen concentration detected by the waste gas oxygen concentration detector into an oxygen concentration signal; The signal transmitted from the concentration converter is compared with the set value of the concentration set value storage device and is sent to the signal generator by the second switch-off (Off), while the third switch is turned on by the operation stop signal generator A first comparator coupled to the first comparator; A second memory device for receiving the oxygen concentration control signal of the operation stop signal generator through the first reset signal generator and determining the current operation state; A second reset signal generator for operating the second and third switches while operating by the first and second storage devices to switch the current operation state to oxygen concentration control or negative pressure management; And a disturbance occurrence storage device for switching the normal oxygen concentration control by operating the first, second, and third switches when disturbance occurs during the oxygen concentration control while being connected to the concentration set value storage device by turning on the first switch Which is a combustion chamber of the coke oven.

The present invention will be described in detail with reference to the drawings.

FIG. 2 is a flow diagram of a method and an apparatus for managing waste combustion gas in a coke oven according to the present invention.

When the third switch 40 is turned on to perform the oxygen concentration control in the off-gas, the second switch 39 is automatically turned off, the first switch 38 is turned on, and the internal negative pressure management of the small- The waste gas oxygen concentration of the waste gas component analyzer 50 is detected and the oxygen concentration is managed by the signal converter 35 and the primary comparator 36. That is, the waste gas component automatic analyzer 50 is installed at the front end of the soot 2 to connect the waste gas component to be detected by the waste gas oxygen concentration detector 34, and the oxygen concentration in the waste gas is sent to the signal converter 35 And transfers this signal to the primary comparator 36 in the concentration converter 35. [

When the signal from the first comparator 36 is transmitted to the signal generator 25, the signal from the signal generator 25 causes the non-return duct 2 to operate by the operation of the hydraulic regulator 26, The oxygen concentration detector 34 detects the oxygen concentration by the waste gas component analyzer 50 inserted in the inside of the reactor 1.

At this time, the detected measured oxygen concentration is measured by the set value of the concentration set value storage device 37, and the oxygen concentration detected by the oxygen concentration detector 34 is converted into an oxygen concentration signal by the converter 36, 36, and the primary comparator 36 compares the set value and the oxygen concentration signal conversion input value to the oxygen concentration set value storage unit 37, The operation of the oxygen concentration adjusting operation is repeated by continuing the operation of the small-scale operation of the air conditioner 25 and the oil pressure regulator 26.

On the other hand, due to the coke oven characteristic, the supply gas is replaced at a cycle of 20 to 30 minutes, so that the operation stop signal generator 27 is operated by the gas shutoff signal, and the operation stop signal generator 27 detects the oxygen concentration The operation of the smoke shielding damper 2 is stopped by instructing the hydraulic regulator 26 to stop the control and at the same time the first reset signal generator 28 is operated and transmitted to the second storage device 30, The storage device 30 determines whether the present operating state of the waste gas oxygen concentration is management-approved negative pressure management, and operates the second reset signal generator 32 in the case of oxygen concentration control.

At this time, the second reset signal generator 32 switches the third switch 40 to the initial negative pressure operating state while turning on the second switch 39, and the first storage device 31 is operated by the gas supply signal The negative pressure operation state is maintained by the negative pressure set value storage device 24 and the second reset signal generator 32 is operated again upon completion of the set value operation of the first storage device 31, (32) causes the second switch (39) to be turned OFF and the third switch (40) to be turned ON to be switched from the negative pressure operating state to the waste gas oxygen concentration operating state. The primary comparison value 36 repeats the operation of comparing the oxygen concentration and instructing the adjustment.

Here, the initial negative pressure set value is determined by the gas shutoff signal so that the first reset signal generator 28 is operated simultaneously with the operation of the operation stop signal generator 27 and the second storage device 30, The operation of the generator 32 inputs the output before the gas shutdown to the operation stop signal generator 27 so that the operation stop signal generator adjusts the negative pressure controller 26 to the initial negative pressure set value.

Also, in the oxygen concentration operating state of the waste gas, the oxygen concentration in the waste gas is automatically controlled in accordance with the adjustment of the flow rate regulator 45 and the calorific value regulator 43 of the combustion gas supply gas, so that the combustion gas temperature and the gas volume according to the ideal gas- The amount of air necessary for the combustion according to the change in the ventilation force of the air conditioner 4 is suitably adjusted in the small-sized soaking tank 2 to prevent the fluctuation of the combustion condition and the oxygen concentration deviation in the waste gas.

The first switch 38 is automatically turned off when the disturbance occurs in the disturbance generation storage device 33 of the oxygen concentration concentration working concentration setting value storage 37 and the second switch 39 is automatically turned on and the third switch 40 The negative pressure is detected by the negative pressure detector 21 and the negative pressure signal is transmitted from the signal generator 25 by the comparator 23.

At this time, the hydraulic pressure regulator 26 operates the low-level dumbbell 2 by the negative pressure signal instructed by the signal generator 25. At the same time, when the operation stop signal generator 27 is turned on with the second switch 39 turned on, The second storage device 30 is operated by the signal of the first reset signal generator 28 to check the negative pressure operation state and after the operation of the first storage device 31 is terminated, The negative pressure of the second comparator 23 is compared with the signal of the second comparator 23 and the operation of instructing the small-scale rebalancing of the bed 2 is repeated until the first switch 38 is turned ON.

When the third switch 40 is turned on, the second switch 39 is automatically turned off, the first switch 38 is turned on, and the oxygen concentration in the waste gas of the internal exhaust gas component analyzer 50 is supplied to the concentration detector 34, The concentration converter 35, the primary comparator 36, the signal generator 25, the concentration set value storage device 37 and the disturbance occurrence storage device 38 are managed.

The present invention can freely control the negative pressure of coke oven off-gas and the management of oxygen concentration in the waste gas, and the oxygen concentration in the waste gas is high at the initial stage of the gas supply according to the characteristics of the supply gas replacement due to the coke oven characteristics. The air is automatically switched to the oxygen concentration control at the time when the oxygen concentration in the waste gas reaches an appropriate management range, thereby preventing excess air at the beginning of combustion and controlling the oxygen concentration in the waste gas as the combustion progresses, In the negative pressure management, when the calorific value of the combustion gas and the flow rate are adjusted, the operator arbitrarily adjusts the manual negative pressure according to the adjustment of the flow rate or the calorific value, or the deviation of each driver occurs. Oxygen concentration control without adjustment or operator arbitration It automatically adjusts the amount of inflow of combustion air automatically so that slight changes due to combustion adjustment can be avoided due to deviation of each operator and incomplete combustion, thus preventing air pollution caused by waste gas exhaust and improving combustion efficiency. Quality improvement and productivity improvement can contribute greatly to the coke oven and the life span due to proper low temperature stability.

Claims (2)

When the internal negative pressure of the small flame 1 detected by the negative pressure detector 21 is converted into a signal by the signal converter 22 and inputted to the comparator 23 and becomes equal to the negative pressure set value of the negative pressure set value storage device 24 In which the negative pressure is regulated by the negative pressure signal generator 25, the hydraulic pressure regulator 26 and the small-sized smoke detector 2 up to the third switch 40, when the third switch 40 is turned on, The second switch 39 and the first switch 38 are automatically turned off and turned on so that the waste gas component is detected by the concentration detector 34 and output to the primary comparator 36 through the signal converter 35. [ The operation of the signal generator 25, the hydraulic regulator 26, and the smoke reduction damper 2 until it becomes equal to the set value of the oxygen concentration set value storage unit 37; The first reset signal generator 28 and the second memory device 30 are operated while the hydraulic pressure regulator 26 and the smoke detector box 2 are stopped by the operation stop signal generator 27 when the supply gas is replaced, Determining whether oxygen concentration control or negative pressure management is performed by the second storage device (30); The second switch 39 and the third switch 40 are turned on and off by the second reset signal generator 32 to be switched to the initial negative pressure state, The second switch 39 and the third switch 40 are turned off by the reset operation of the first storage device 31 operated according to the signal and the re-operation of the second reset signal generator 32, ), Turning on (turning on) the waste gas oxygen concentration control; The first, second and third switches 38, 39 and 40 are automatically turned OFF, ON and OFF respectively when disturbance occurs in the disturbance generation storage device 33 during the oxygen concentration control, The comparator 23 switches the first, second and third switches 38, 39 and 40 to the OFF state, the ON state and the OFF state, respectively, by the signal of the negative pressure detector 21, And adjusting the oil pressure regulator (26) and the smoke reducing doser (2) until the oil is turned off (OFF), and transferring the oil to the oxygen concentration control. A negative pressure detector 21 installed to detect the internal negative pressure of the small burner 1; A signal converter 22 for converting the negative pressure detected by the negative pressure detector 21 into a signal; A comparator 23 for comparing the signal transmitted from the signal converter 22 with the set value of the negative pressure set value storage device 24 and sending it to the negative pressure signal generator 25; A hydraulic pressure regulator 26 for receiving the signal of the negative pressure signal generator 25 and operating the non-return duct 2; An operation stop signal generator 27 for receiving a signal from the hydraulic pressure regulator 26 of the comparator 23 and sending a signal to the hydraulic cylinder 26 again; And a first storage device (31) for sending a set value to the negative pressure set value storage device (24) by an external gas supply signal, characterized in that a waste gas component of the small scale (1) is detected A waste gas component analyzer (50); A waste gas oxygen concentration detector 34 for detecting the oxygen concentration in the waste gas detected by the waste gas component analyzer 50; A concentration converter (35) for converting the oxygen concentration detected by the waste gas oxygen concentration detector (34) into an oxygen concentration signal; The signal transmitted from the concentration converter 35 is compared with the set value of the concentration set value storage device 37 and sent to the signal generator 25 by turning off the second switch 39, (36) connected to the operation stop signal generator (27) by the ON state of the operation stop signal generator (40); A second memory device (30) for receiving the oxygen concentration control signal of the operation stop signal generator (27) through the first reset signal generator (28) and determining the current operation state; A second reset signal generator 32 which is operated by the first and second storage devices 31 and 30 and operates the second and third switches 39 and 40 to switch the current operation state to oxygen concentration control or negative pressure management, Wow; The first, second and third switches 38, 39 and 40 are operated when disturbance occurs during the oxygen concentration control while being connected to the concentration set value storage device 37 by the ON switch of the first switch 38, And a disturbance generation memory (33) for switching the oxygen concentration control. ※ Note: It is disclosed by the contents of the first application.