JP2012158700A - Temperature control device and temperature control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve continuously stable temperature control even under a severe condition.SOLUTION: The temperature control device includes: a first temperature sensor 128 for measuring a temperature at a first position to generate a first temperature measuring value; a second temperature sensor 130 for measuring a temperature at a second position where the environmental condition is different from the first position to generate a second temperature measuring value; a temperature measuring value estimating part 132 for estimating the first temperature measuring value from the second temperature measuring value based on correlation of the first and the second temperature measuring values to generate an estimating value; and a control input switching part 134 switches control input from the first temperature measuring value to the estimating values when the first sensor is determined to be abnormal.

Description

  The present invention relates to a temperature control device and a temperature control method for performing temperature control under severe environmental conditions.

  2. Description of the Related Art In recent years, a technology has been developed that gasifies solid raw materials such as coal, biomass, and tire chips to generate gasified gas instead of petroleum. The gasified gas generated in this way can be used for efficient power generation systems such as Integrated Coal Gasification Combined Cycle (IGCC), hydrogen production, synthetic fuel (synthetic petroleum) production, chemical fertilizer ( (Urea) and other chemical products. Among solid raw materials used as raw materials for gasification gas, coal, in particular, has a recoverable period of about 150 years, more than three times the recoverable period of oil, and reserves are unevenly distributed compared to oil. Therefore, it is expected as a natural resource that can be stably supplied over a long period of time.

  Such a coal gasification process has been performed by partial oxidation using oxygen or air. However, since it is necessary to perform partial oxidation at a high temperature of 2000 ° C., the cost of the gasification furnace increases. Had. In order to solve this problem, a technology for gasifying coal at about 700 ° C. to 900 ° C. using water vapor has been developed.

  For example, in a circulating fluidized bed gasification system, the gasification raw material is gasified by the heat of a fluidized medium (eg, sand) that flows in the presence of water vapor, and the fluidized medium derived from the gasification furnace is heated in the combustion furnace. Circulate between the combustion furnace and the gasification furnace. In order to maintain the above-mentioned temperature necessary for gasification appropriately, the temperature of the fluidized medium is controlled in a combustion furnace. In order to perform temperature control, it is necessary to measure the temperature in the combustion furnace, but in the combustion furnace, the sand that is the fluidized medium flows at high speed together with the combustion gas, so the temperature sensor is normal due to disconnection etc. May not function properly.

  Therefore, as a technology for continuing temperature control even if the temperature sensor stops functioning normally, if the temperature sensor is in the disconnected state, the temperature measurement value immediately before the disconnected state is held, and even in the disconnected state, a fixed value (immediately before (For example, Patent Document 1). In addition, assuming that multiple temperature sensors are installed at the position where temperature measurement is to be performed and control is performed based on the average value of the multiple temperature measurement values of the multiple temperature sensors, each of the multiple temperature measurement values is There is also disclosed a technique for determining whether or not a temperature is included in a predetermined range and not reflecting a temperature measurement value not included in an average value as an abnormal value (for example, Patent Document 2).

Japanese Patent No. 3440838 JP 2006-330944 A

  However, in the circulating fluidized bed gasification system, the target temperature changes depending on the process conditions. Therefore, by simply using the technique of Patent Document 1 and maintaining the previous temperature, the process conditions are appropriately set. It becomes impossible to cope. Also, in a combustion furnace in which a solid fluidized medium is scattered at high speed as in a circulating fluidized bed gasification system, even if there are a plurality of temperature sensors as in the technique of Patent Document 2, disconnection occurs one after another under the same severe conditions. This makes it impossible to obtain a desired appropriate temperature measurement value.

  In view of such problems, the present invention has an object to provide a temperature control device and a temperature control method capable of continuously executing stable temperature control even under severe conditions.

  In order to solve the above-described problem, a temperature control device of the present invention measures a temperature at a first position, generates a first temperature measurement value, a first position, and an environmental condition. Based on the correlation between the first temperature measurement value and the second temperature measurement value, the second temperature sensor that measures the temperature of the second position to be different and generates the second temperature measurement value, When it is determined that the first temperature measurement value is estimated from the two temperature measurement values and the temperature measurement value estimation unit that generates the estimation value and the first temperature sensor are abnormal, the control input is the first temperature. A control input switching unit that switches from the measured value to the estimated value is provided.

  The gasification raw material is gasified by the heat of the fluidized medium in the presence of water vapor to generate a gasified gas, and a gasification furnace for deriving the fluidized medium and unreacted char; A combustion furnace that burns the char to heat the fluid medium, derives the heated fluid medium and combustion gas, a fuel supply unit that controls a supply amount of auxiliary fuel that assists combustion in the combustion furnace, and a fluid medium; Used in a circulating fluidized bed gasification system comprising a medium separator for separating combustion gas and introducing a fluidized medium into a gasification furnace, wherein the first position is in the combustion furnace and the second position is In the vicinity of the outlet of the combustion gas in the medium separator, and the control input switching unit determines that the first temperature sensor is abnormal, the control input in the fuel supply unit is estimated from the first temperature measurement value. You may switch to.

  The estimated value is obtained by adding a temperature difference obtained based on the flow rate of air introduced into the combustion furnace and the second temperature measurement value to the second temperature measurement value, or by calculating the flow rate of air introduced into the combustion furnace. The second temperature measurement value may be derived by multiplying the second temperature measurement value by a coefficient obtained based on the second temperature measurement value.

  In order to solve the above-described problem, the first temperature sensor that measures the temperature at the first position and generates the first temperature measurement value, and the second position that has different environmental conditions from the first position. The temperature control method of the present invention, which controls the temperature using a temperature control device that includes a second temperature sensor that measures temperature and generates a second temperature measurement value, includes the first temperature measurement value and the second temperature measurement value. If the first temperature measurement value is estimated from the second temperature measurement value based on the correlation between the temperature measurement values, the estimated value is generated, and it is determined that the first temperature sensor is abnormal, the control input Is switched from the first measured temperature value to the estimated value.

  In the present invention, stable temperature control can be continuously executed even under severe conditions.

It is a functional block diagram for demonstrating a circulating fluidized bed gasification system. It is a control block diagram for demonstrating the control system of a fuel supply part. It is explanatory drawing which showed an example of correlation with the 1st temperature measurement value and the 2nd temperature measurement value. It is explanatory drawing which showed an example of MAP. It is a control block diagram for demonstrating the control system of a fuel supply part. It is a flowchart which shows the flow of a process of a temperature control method.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

  In the present embodiment, examples of the temperature control target of the temperature control device include the circulating fluidized bed gasification system 100, particularly, the circulating fluidized bed gasification system 100 also called a two-column fluidized bed gasification furnace. In the circulating fluidized bed gasification system 100, a fluid medium (for example, sand such as silica sand) circulates between the gasification furnace and the combustion furnace as a heat medium. The temperature control device plays a role in the circulating fluidized bed gasification system 100 to heat and maintain the fluidized medium from which heat has been removed by gasification and circulation at a predetermined temperature.

(Circulating fluidized bed gasification system 100)
FIG. 1 is a functional block diagram for explaining a circulating fluidized bed gasification system 100 according to the present embodiment. The circulating fluidized bed gasification system 100 includes a gasification raw material supply unit 108, a gasification furnace 110, a reforming furnace 112, a combustion furnace 114, a medium separator 116, a combustion furnace air introduction unit 118, an air flow rate. Measurement unit 120, fuel supply unit 122, control valve 124, fuel flow rate measurement unit 126, first temperature sensor 128, second temperature sensor 130, temperature measurement value estimation unit 132, and control input switching Unit 134, correlation deriving unit 136, and steam supply device 138. Moreover, in FIG. 1, the solid line arrow shows the flow of the substance, and the broken line arrow shows the flow of the control signal. Here, the first temperature sensor 128, the second temperature sensor 130, the temperature measurement value estimation unit 132, and the control input switching unit 134 function as a temperature control device.

  The gasification raw material supply unit 108 supplies the gasification furnace 110 with gasification raw materials such as coal such as brown coal, solid raw materials such as petroleum coke (petro coke), biomass and tire chips, and liquid raw materials such as black liquor.

  In the gasification furnace 110, sand as a fluid medium is introduced from above the gasification furnace 110. In the gasification furnace 110, the steam supply device 138 introduces water vapor from below the gasification furnace 110 to form a fluidized bed (a bubbling fluidized bed). When the gasification raw material is supplied from the gasification raw material supply unit 108 to the upstream side of the fluidized bed, the gasification raw material is gasified by a reduction reaction at a temperature of 700 ° C. to 900 ° C. in the presence of water vapor (water vapor gas Gasification gas is generated. When the gasification raw material is coal, the gasification gas contains hydrogen, carbon monoxide, carbon dioxide, and methane as main components, and contains a small amount of tar, nitrogen, nitrogen compounds, sulfur, and sulfur compounds.

  Here, the circulating fluidized bed type gasification furnace 110 will be described as an example, but if it is a gasification furnace that gasifies the gasification raw material, a simple fluidized bed type gasification furnace or sand will be used. It may be a moving bed type gasification furnace that forms a moving bed by flowing down vertically.

  In addition, the fluidized medium in which the fluidized bed is formed in the gasification furnace 110 and the gasification reaction is finished is the combustion furnace 114 together with char (residue of gasification raw material such as biomass, not limited to coal) which is an unreacted gasification raw material. To be introduced.

  The reforming furnace 112 heats the gasification gas generated in the gasification furnace 110 to 900 ° C. to 1500 ° C., adds oxygen and air, and reforms (oxidation reforming) the tar contained in the gasification gas. The gasified gas reformed in the reforming furnace 112 is further removed (purified) from the dust, sulfur, ammonia, and chlorine in the subsequent processing section to become a purified gasified gas.

  Combustion furnace 114 is formed in a cylindrical shape extending in the vertical direction, heats the introduced fluid medium by combustion of the introduced char and auxiliary fuel, and further flows through the combustion furnace 114 at a high speed by being supplied with air. Make it.

  The medium separator (cyclone) 116 separates the fluidized medium and the combustion gas heated to about 1000 ° C. in the combustion furnace 114, lowers the fluidized medium, and introduces the fluidized medium into the gasification furnace 110. Further, the combustion gas separated by the medium separator 116 is heat recovered by a boiler or the like.

  Thus, the fluidized medium circulates through the gasification furnace 110, the combustion furnace 114, and the medium separator 116. At this time, the flow rate of the fluidized medium in the combustion furnace 114 is adjusted in the combustion furnace 114 in order to adjust the flow amount of the gasification raw material (the amount of gasification gas generated), and 700 required for gasification in the gasification furnace 110. Temperature control is performed in the combustion furnace 114 in order to appropriately maintain a temperature of from 0C to 900C.

  The combustion furnace air introduction section 118 is used to burn the char introduced into the combustion furnace 114 and to cause the fluid medium introduced into the combustion furnace 114 to fluidize upward into the combustion furnace 114 from below. Supply. The combustion furnace air introduction unit 118 can control, for example, the flow amount of the fluid medium in the combustion furnace 114 and the gasification furnace 110 by adjusting the flow rate of air.

  The air flow rate measurement unit 120 measures the flow rate of air supplied from the combustion furnace air introduction unit 118 to the combustion furnace 114. The combustion furnace air introduction unit 118 controls the air flow rate by feeding back the air flow rate measured by the air flow rate measurement unit 120.

  The fuel supply unit 122 supplies auxiliary fuel into the combustion furnace 114 through the control valve 124 in order to heat the temperature of the fluid medium to a predetermined value. As described above, char is introduced into the combustion furnace 114, and the fluidized medium is heated by combustion of the char. However, since the amount of char changes according to the gasification process, the fuel supply unit 122 compensates for the shortage of char and adds auxiliary fuel to control the temperature in the combustion furnace 114. Here, as with the gasifier 110, coal, biomass, or the like is used as the auxiliary fuel.

  The fuel flow rate measurement unit 126 measures the flow rate of auxiliary fuel supplied from the fuel supply unit 122 to the combustion furnace 114. The fuel supply unit 122 controls the flow rate of the auxiliary fuel by feeding back the flow rate of the auxiliary fuel measured by the fuel flow rate measurement unit 126.

  The first temperature sensor 128 is composed of a thermocouple or a thermistor, measures the temperature at a predetermined position (first position) in the combustion furnace 114, and generates a first temperature measurement value. As described above, in the combustion furnace 114, according to the amount of air supplied from the combustion furnace air introduction unit 118, the fluid medium (sand) flows at high speed while being scattered. Therefore, it can be said that the first position where the first temperature sensor 128 is installed is a very severe condition as an environmental condition.

  The fuel supply unit 122 controls the flow rate of the auxiliary fuel based on the flow rate measured by the fuel flow rate measurement unit 126 and the first temperature measurement value measured by the first temperature sensor 128.

  FIG. 2 is a control block diagram for explaining a control system of the fuel supply unit 122. In the outer loop of FIG. 2, the subtracter 150 subtracts the first temperature measurement value measured by the first temperature sensor 128 from the temperature set value set as the target value, and the PID function unit 152 adds the PID coefficient. Thus, the target value of the auxiliary fuel is determined. In the inner loop of FIG. 2, the subtractor 154 subtracts the flow rate measured by the fuel flow rate measurement unit 126 from the target value of the auxiliary fuel, and the PID function unit 156 adds a PID coefficient so that the flow rate of the auxiliary fuel is increased. It is determined and transmitted to the control valve 124.

  Thus, regardless of the amount of char introduced into the combustion furnace 114, the flow rate of the auxiliary fuel can be appropriately controlled according to the temperature in the combustion furnace 114, and the temperature in the combustion furnace 114 is set as a target value. The set temperature set value can be maintained.

  However, in the combustion furnace 114, since the sand that is a fluid medium flows at a high speed together with the combustion gas, the first temperature sensor 128 may not function normally due to disconnection or the like. Therefore, in the present embodiment, the second temperature sensor 130 is provided independently of the first temperature sensor 128.

  The second temperature sensor 130 is composed of a thermocouple or a thermistor, and the position where the first position differs from the environmental condition, for example, the first position is severe as the environmental condition (flows at high speed while sand is scattered). Etc.), it is installed at the outlet (second position) of the combustion gas in the medium separator 116 where the environmental conditions are different from the first position, and the temperature of the second position is measured and the second position is measured. The temperature measurement value of is generated. The present embodiment is characterized in that a plurality of temperature sensors such as the first temperature sensor 128 and the second temperature sensor 130 are respectively arranged at different environmental conditions. However, the first position and the second position are in a predetermined positional relationship, and it is necessary that the first temperature measurement value and the second temperature measurement value have a correlation. For example, in the present embodiment, the first position and the second position are common to each other in that they are in communication with each other and serve as a circulation path for the fluid medium, such as the combustion furnace 114 and the medium separator 116. It can be said that the measured temperature value and the second measured temperature value have a correlation.

  The temperature measurement value estimation unit 132 estimates the first temperature measurement value from the second temperature measurement value based on the correlation between the first temperature measurement value and the second temperature measurement value, and generates an estimated value. . As described above, since the first temperature sensor 128 and the second temperature sensor 130 are installed so as to have a correlation, the other can be estimated from one using the correlation. In particular, in the present embodiment, a case where the first temperature measurement value is estimated from the second temperature measurement value by the second temperature sensor 130 will be described.

  FIG. 3 is an explanatory diagram showing an example of a correlation between the first temperature measurement value and the second temperature measurement value. Since the second temperature sensor 130 is located downstream from the first temperature sensor 128, the second temperature measurement value falls from the first temperature measurement value unless it is heated in the middle thereof. Further, although the positional relationship between the second temperature sensor 130 and the first temperature sensor 128 is fixed, the amount of decrease in the temperature measurement value is from the position of the first temperature sensor 128 to the second temperature sensor 130. Therefore, the flow rate of the air in the combustion furnace 114, that is, the flow rate measured by the air flow rate measurement unit 120 is greatly affected.

  Therefore, in FIG. 3A, based on the flow rate measured by the air flow rate measurement unit 120 as the flow rate of the air introduced into the combustion furnace 114 and the second temperature measurement value, for example, FIG. The first temperature measurement value and the theory are obtained from the correlation obtained by adding the temperature difference between the first temperature measurement value and the second temperature measurement value to the second temperature measurement value, which is obtained from the MAP (table) shown in FIG. Equally estimated values can be derived. Further, as shown in FIG. 3B, based on the flow rate measured by the air flow rate measurement unit 120 and the second temperature measurement value, for example, the coefficient obtained from the MAP shown in FIG. It is also possible to derive an estimated value by multiplying the measured temperature value.

  Further, the MAP shown in FIG. 3 can be obtained from actually measured data when the circulating fluidized bed gasification system 100 is actually operated. Here, the correlation is mapped to a plurality of points each of the flow rate measured by the air flow rate measurement unit 120 and the second temperature measurement value. The temperature measurement value estimation unit 132 derives an estimated value between the plurality of points by an interpolation process such as linear interpolation.

  Further, in FIGS. 3A and 3B, based on the flow rate measured by the air flow rate measuring unit 120 and the second temperature measurement value, a temperature difference and a coefficient are once obtained, and the values are obtained. Although adding or multiplying, a MAP that directly derives an estimated value based on the flow rate measured by the air flow rate measuring unit 120 and the second temperature measurement value can be provided as shown in FIG. . However, the numerical values shown in FIG. 3 and FIG. 4 are merely examples, and it goes without saying that actual values may be different from the numerical values.

  The control input switching unit 134 always monitors whether or not the first temperature sensor 128 is functioning normally, and if it is determined that the first temperature sensor 128 is abnormal (not normal), the fuel supply unit The control input at 122 is switched from the first measured temperature value obtained from the first temperature sensor 128 to the estimated value estimated by the measured temperature value estimation unit 132.

  FIG. 5 is a control block diagram for explaining a control system of the fuel supply unit 122. Here, control input switching control by the control input switching unit 134 is added to the control system described in FIG. As described above, since the first temperature sensor 128 is installed at a position where the environmental conditions are more severe than those of the second temperature sensor 130, the first temperature sensor may not function normally. In the present embodiment, since the temperature measurement value estimation unit 132 generates the estimated value of the first temperature measurement value, if the first temperature sensor 128 indicates an abnormality, instead of the first temperature measurement value, By using the estimated value, the temperature control of the fuel supply unit 122 can be continued.

  The correlation deriving unit 136 performs the first temperature measurement value obtained from the first temperature sensor 128 and the estimated value obtained from the temperature measurement value estimation unit 132 while the first temperature sensor 128 is functioning normally. And the difference value between the first measured temperature value and the estimated value is reflected in the correlation. Since the estimated value is not required while the first temperature sensor 128 is functioning normally, here, the correlation is calibrated using the estimated value while functioning normally.

  The temperature measurement value estimation unit 132 generates an estimated value based on, for example, the MAP shown in FIG. 3 based on a predetermined correlation. However, the correlation may change depending on aging, design change, or the like. Here, for example, the correlation deriving unit 136 reflects a value obtained by performing a low-pass filter (LPF) or the like on the difference value between the first temperature measurement value and the estimated value in the MAP, so that the appropriate value is obtained in real time. Correlation can be constructed, and accordingly, the temperature measurement value estimation unit 132 can derive the estimated value of the first temperature measurement value with higher accuracy.

  As described above, in the circulating fluidized bed gasification system 100 described above, even under severe conditions, even if the first temperature sensor 128 becomes abnormal, the second condition under which the first temperature sensor 128 is more quiet. Since the tracking control can be performed by switching to the temperature sensor 130, the temperature control device can continuously perform stable temperature control, and is necessary for efficient gasification in the combustion furnace 114. Appropriate combustion can be performed. In this way, the operator can continue stable temperature control without being aware of whether or not the first temperature sensor 128 is operating normally.

(Temperature control method)
FIG. 6 is a flowchart showing a process flow of the temperature control method using the circulating fluidized bed gasification system 100 according to the present embodiment.

  As shown in FIG. 6, the combustion furnace air introduction unit 118 determines a target flow rate of air supplied to the combustion furnace 114 in accordance with a target flow amount of the fluid medium in the gasification furnace 110, and the target flow rate The air flow rate is controlled based on the flow rate measured by the air flow rate measuring unit 120 (S200).

  Subsequently, the temperature measurement value estimation unit 132 estimates the first temperature measurement value from the second temperature measurement value based on the correlation between the first temperature measurement value and the second temperature measurement value, and the estimated value Is generated (S202). The control input switching unit 134 monitors whether or not the first temperature sensor 128 is functioning normally (S204), and supplies fuel while the first temperature sensor 128 is functioning normally (YES in S204). When the first temperature measurement value is selected as the control input of the unit 122 (S206) and the first temperature sensor 128 is not functioning normally (NO in S204), the temperature measurement is performed as the control input of the fuel supply unit 122. The estimated value estimated by the value estimating unit 132 is selected (S208).

  As described with reference to FIG. 5, the fuel supply unit 122 determines the flow rate of the auxiliary fuel based on the selected control input and the flow rate measured by the fuel flow rate measurement unit 126, and sends the flow rate to the control valve 124. Then, the control valve 124 supplies the auxiliary fuel at the flow rate transmitted from the fuel supply unit 122 to the combustion furnace 114 (S212).

  The fluid medium and the combustion gas heated in the temperature-controlled combustion furnace 114 are separated from the fluid medium and the combustion gas by the medium separator 116, and the separated fluid medium is introduced into the gasification furnace 110. (S214). In the gasification furnace 110, the gasification raw material is supplied to the introduced fluid medium, and the gasification raw material is gasified by the heat of the fluid medium in the presence of water vapor (S216). The fluid medium that has finished its role and the unreacted char are again introduced into the combustion furnace 114 and heated (S218). In this way, the fluidized medium circulates while the temperature of the fluidized medium is controlled to be a predetermined temperature in the gasification furnace 110.

  Even in the temperature control method described above, it is possible to continuously perform stable temperature control even under severe conditions.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Is done.

  Note that each step of the temperature control method of the present specification does not necessarily have to be processed in time series in the order described in the flowchart, and may include processing in parallel or by a subroutine.

  The present invention can be used for a temperature control device and a temperature control method for performing temperature control under severe environmental conditions.

DESCRIPTION OF SYMBOLS 100 ... Circulating fluidized bed gasification system 110 ... Gasification furnace 114 ... Combustion furnace 116 ... Medium separator 118 ... Combustion furnace air introduction part 120 ... Air flow measurement part 122 ... Fuel supply part 124 ... Control valve 126 ... Fuel flow measurement part 128 ... first temperature sensor 130 ... second temperature sensor 132 ... temperature measurement value estimation unit 134 ... control input switching unit 136 ... correlation derivation unit

Claims (4)

A first temperature sensor for measuring a temperature at a first position and generating a first temperature measurement value;
A second temperature sensor that measures a temperature at a second position that is different from the first position in environmental conditions, and generates a second measured temperature value;
Temperature measurement value estimation that estimates the first temperature measurement value from the second temperature measurement value based on the correlation between the first temperature measurement value and the second temperature measurement value, and generates an estimated value And
A control input switching unit that switches a control input from the first measured temperature value to the estimated value when it is determined that the first temperature sensor is abnormal;
A temperature control device comprising: A gasification furnace that gasifies the gasification raw material by heat of the fluidized medium in the presence of water vapor to generate a gasified gas, and derives unreacted char from the fluidized medium;
A combustion furnace that burns unreacted char in the presence of the fluidized medium to heat the fluidized medium and derives the heated fluidized medium and combustion gas;
A fuel supply unit for controlling a supply amount of auxiliary fuel for assisting combustion in the combustion furnace;
A medium separator for separating the fluid medium and the combustion gas and introducing the fluid medium into the gasification furnace;
Used in a circulating fluidized bed gasification system,
The first position is in the combustion furnace;
The second position is near the outlet of the combustion gas in the media separator;
The control input switching unit switches the control input in the fuel supply unit from the first measured temperature value to the estimated value when it is determined that the first temperature sensor is abnormal. Temperature control device.   The estimated value is obtained by adding a temperature difference obtained based on a flow rate of air introduced into the combustion furnace and the second temperature measurement value to the second temperature measurement value, or introducing the temperature difference into the combustion furnace. The temperature control device according to claim 2, wherein the temperature control device is derived by multiplying the second temperature measurement value by a coefficient obtained based on the flow rate of the measured air and the second temperature measurement value. A first temperature sensor that measures a temperature at the first position and generates a first temperature measurement value; a temperature at a second position that differs from the first position in environmental conditions; A temperature control method for controlling the temperature using a temperature control device comprising a second temperature sensor that generates a temperature measurement value of
Based on the correlation between the first temperature measurement value and the second temperature measurement value, the first temperature measurement value is estimated from the second temperature measurement value, and an estimated value is generated,
When it is determined that the first temperature sensor is abnormal, a control input is switched from the first measured temperature value to the estimated value.

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