Furnace pressure control system, combustion furnace, and furnace pressure control method

Abstract

To maintain furnace pressure at positive pressure and to suppress damage to a damper caused by high temperature.SOLUTION: An in-furnace pressure control system 3 for controlling an internal pressure of a furnace body 1 of a combustion furnace 100 comprises: a pressure sensor 31 which is provided on the furnace main body 1 and detects the internal pressure of the furnace main body 1; a temperature sensor 32 which is provided on an exhaust cylinder 2 connected to the furnace main body 1 and detects a temperature of exhaust gas in the exhaust cylinder 2; air supply means 33 which is provided on the exhaust cylinder 2 upstream of a damper 21 and supplies air into the exhaust cylinder 2; and a control device 34 for controlling an operation of the air supply means 33. The control device 34 controls a flow rate of air from the air supply means 33 so that the pressure detected by the pressure sensor 31 is a positive pressure and that a temperature detected by the temperature sensor 32 is lower than a prescribed value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a furnace pressure control system, a combustion furnace, and a furnace pressure control method. [Background technology]

[0002] For example, in the heating furnace disclosed in Patent Document 1, a high-temperature damper is provided in the flue. The opening degree of the high-temperature damper is controlled based on the pressure inside the furnace body detected by a pressure sensor. With this configuration, the pressure inside the furnace body is maintained at a slightly positive pressure. A dilution air blower is connected to the flue upstream of the high-temperature damper. The dilution air blower supplies dilution air to the flue, and the exhaust gas in the flue is cooled by the dilution air. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-212016 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, as described above, the opening of the high-temperature damper is controlled based on the pressure detected by the pressure sensor, thereby maintaining a slightly positive pressure inside the furnace body. Generally, during low combustion, the flow rate of exhaust gas decreases, making it necessary to narrow the opening of the high-temperature damper. However, there is a limit to the damper's closing performance. As a result, exhaust gas may leak through the gap between the damper and the flue during low combustion. In this case, the pressure may not be maintained at a positive pressure. Therefore, it is possible to fill the gap between the damper and the flue with a sealing material. However, in furnaces that operate at high temperatures, the sealing material would be exposed to high-temperature exhaust gas, making it impossible to fill the gap with sealing material.

[0005] Furthermore, as mentioned above, the damper may be exposed to high-temperature exhaust gases. If the damper is damaged by thermal shock and temperature gradients due to high temperatures, it may be necessary to shut down the furnace until the damper is repaired. Therefore, refractory materials are sometimes used for the damper. However, refractory materials are expensive, large, and heavy.

[0006] In consideration of the above-mentioned problems, the present invention aims to provide a furnace pressure control system and a furnace pressure control method that can maintain a positive furnace pressure and prevent damage to a damper due to high temperatures. The present invention also includes a combustion furnace equipped with such a furnace pressure control system. [Means for solving the problem]

[0007] In order to solve the above problems, one aspect of the present invention is an in-furnace pressure control system for controlling the pressure inside the furnace body of a combustion furnace, comprising: a pressure sensor provided in the furnace body and detecting the pressure inside the furnace body; a temperature sensor provided in an exhaust stack connected to the furnace body and detecting the temperature of the exhaust gas inside the exhaust stack; air supply means provided in the exhaust stack upstream of the damper and supplying air into the exhaust stack; and a control device for controlling the operation of the air supply means, wherein the control device adjusts the flow rate of air from the air supply means so that the pressure detected by the pressure sensor becomes positive and the temperature detected by the temperature sensor becomes less than a predetermined value. The control device calculates a first command value for making the pressure positive, calculates a second command value for making the temperature less than a predetermined value, and adjusts the flow rate of air from the air supply means based on the larger of the first command value and the second command value. The furnace pressure control system further includes a flow meter for detecting the flow rate of fuel supplied to the burner, and a deterioration state determination unit for determining the deterioration state of a sealing element in the combustion furnace based on the fuel flow rate detected by the flow meter, the pressure detected by the pressure sensor, and the first command value. .

[0010] When it is determined that the sealing element is deteriorated, the deterioration state determination unit may notify an operator of the deterioration state.

[0011] The temperature sensor may be provided downstream of the damper in the exhaust stack.

[0012] Another aspect of the present invention is a combustion furnace including any one of the above-described internal furnace pressure control systems, a furnace body, and an exhaust stack connected to the furnace body.

[0013] Yet another aspect of the present invention is a furnace pressure control method for controlling the pressure inside the furnace body of a combustion furnace, comprising the steps of: receiving the pressure inside the furnace body from a pressure sensor provided in the furnace body; receiving the temperature of the exhaust gas inside the exhaust stack from a temperature sensor provided in an exhaust stack connected to the furnace body; and supplying air into the exhaust stack from an air supply means provided upstream of the damper in the exhaust stack so that the pressure detected by the pressure sensor becomes positive and the temperature detected by the temperature sensor becomes less than a predetermined value; Calculating a first command value for making the pressure positive, and calculating a second command value for making the temperature less than a predetermined value; Including supplying air from the air supply means to the inside of the exhaust stack includes adjusting the flow rate of air from the air supply means based on the larger command value of the first command value and the second command value, and the furnace pressure control method further includes receiving a flow rate of fuel supplied to the burner from a flow meter, and determining a deterioration state of a sealing element in the combustion furnace based on the fuel flow rate detected by the flow meter, the pressure detected by the pressure sensor, and the first command value. .

[0016] The method for controlling reactor pressure may further include notifying an operator of a deterioration state when it is determined that the sealing element is deteriorated. [Effects of the Invention]

[0017] According to the present invention, the furnace pressure can be maintained at a positive pressure, and damage to the damper due to high temperatures can be suppressed. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic diagram showing a combustion furnace equipped with an internal furnace pressure control system according to an embodiment. [Figure 2] FIG. 2 is a flowchart showing the operation of the control device in FIG. [Figure 3] FIG. 3 is a flowchart showing the operation of the PC in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Specific dimensions, materials, numerical values, etc. shown in the embodiments are merely examples for facilitating understanding of the invention and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation. Elements not directly related to the present invention are not shown.

[0020] FIG. 1 is a schematic diagram showing a combustion furnace (hereinafter simply referred to as "furnace") 100 equipped with a furnace pressure control system 3 according to an embodiment. The furnace 100 is a combustion furnace that generates exhaust gases through combustion. For example, the furnace 100 may be a heat treatment furnace that performs heat treatment such as quenching. However, the furnace 100 is not limited thereto and may be various types of combustion furnaces. The furnace 100 may use various fuels such as gas or oil.

[0021] The furnace 100 includes a furnace body 1, an exhaust stack 2, and an in-furnace pressure control system 3. The in-furnace pressure control system 3 also includes a pressure sensor 31, a temperature sensor 32, an air supply means 33, a control device 34, and a PC (deterioration state determination unit) 35.

[0022] The furnace body 1 includes a combustion chamber 11 and a burner 12. A flow meter 13 is connected to the burner 12 to detect the flow rate of fuel supplied to the burner 12. The flow meter 13 transmits a signal indicating the flow rate to the PC 35.

[0023] The exhaust stack 2 is connected to the furnace body 1 and discharges the exhaust gas generated in the furnace body 1 to the outside. The exhaust stack 2 includes a damper 21. The damper 21 adjusts the flow rate of the exhaust gas discharged to the outside by controlling its opening. The opening of the damper 21 is adjusted by a motor M1. The motor M1 is driven by a motor driver D1 based on a signal from a control device 34.

[0024] The pressure sensor 31 is provided in the furnace body 1. The pressure sensor 31 detects the pressure inside the combustion chamber 11 (hereinafter simply referred to as "furnace pressure"). The pressure sensor 31 transmits a signal indicating the furnace pressure to the control device 34 and the PC 35.

[0025] The temperature sensor 32 is provided in the exhaust stack 2. The temperature sensor 32 detects the temperature of the exhaust gas in the exhaust stack 2. In this embodiment, the temperature sensor 32 is provided downstream of the damper 21. The temperature sensor 32 transmits a signal indicating the temperature to the control device 34. The temperature sensor 32 may also transmit a signal indicating the temperature to the PC 35.

[0026] The air supply means 33 supplies air into the exhaust stack 2. The air supply means 33 includes a nozzle 33a. The nozzle 33a is provided upstream of the damper 21 in the exhaust stack 2. In this embodiment, a plurality of nozzles 33a are provided at intervals on the side wall of the exhaust stack 2. An air control valve 33b is connected to the nozzle 33a. The flow rate of air supplied to the nozzle 33a is adjusted by controlling the aperture of the air control valve 33b. The aperture of the air control valve 33b is adjusted by a motor M2. The motor M2 is driven by a motor driver D2 based on a signal from the control device 34. The source of air supplied to the air supply means 33 may be the same as, for example, a source (not shown) that supplies combustion air to the burner 12.

[0027] The control device 34 includes an in-furnace pressure regulator 34a, an exhaust temperature regulator 34b, a first computing unit 34c, and a second computing unit 34d.

[0028] The furnace pressure regulator 34a is communicably connected to the pressure sensor 31 and receives a signal indicating the furnace pressure. An operator inputs a target value of the furnace pressure to the furnace pressure regulator 34a. The furnace pressure regulator 34a calculates a command value (hereinafter referred to as an opening command value) for adjusting the opening of the damper 21 so that the difference between the furnace pressure received from the pressure sensor 31 and the target value of the furnace pressure becomes less than a predetermined threshold value. The furnace pressure regulator 34a transmits the calculated opening command value to the motor driver D1 and the first computing unit 34c.

[0029] The motor driver D1 converts the opening command value received from the furnace pressure regulator 34a into a control signal for the motor M1 to control the motor M1, thereby adjusting the opening of the damper 21.

[0030] The first computing unit 34c is communicatively connected to the furnace pressure regulator 34a and receives an opening command value. The first computing unit 34c converts the signal received from the furnace pressure regulator 34a and calculates a command value (hereinafter referred to as a first command value) for adjusting the opening of the air control valve 33b so as to maintain the furnace pressure at a positive pressure. The first computing unit 34c transmits the calculated first command value to the second computing unit 34d and the PC 35.

[0031] The exhaust gas temperature controller 34b is communicatively connected to the temperature sensor 32 and receives a signal indicating the temperature of the exhaust gas in the exhaust stack 2. An operator inputs a target value for the exhaust gas temperature to the exhaust gas temperature controller 34b. The exhaust gas temperature controller 34b calculates a command value (hereinafter referred to as a second command value) for adjusting the opening of the air control valve 33b so that the difference between the exhaust gas temperature received from the temperature sensor 32 and the target value for the exhaust gas temperature is less than a predetermined threshold. The exhaust gas temperature controller 34b transmits the calculated second command value to the second calculator 34d. The exhaust gas temperature controller 34b may also transmit the calculated second command value to the PC 35.

[0032] The second computing unit 34d compares the first command value for maintaining the furnace pressure at a positive pressure received from the first computing unit 34c with the second command value for adjusting the temperature of the exhaust gas received from the exhaust gas temperature regulator 34b, and selects the larger command value from the first command value and the second command value. The second computing unit 34d transmits the selected command value to the motor driver D2. The second computing unit 34d may also transmit the selected command value to the PC 35.

[0033] The motor driver D2 controls the motor M2 based on the command value received from the second computing unit 34d, and thereby adjusts the opening of the air control valve 33b, that is, the flow rate of air supplied into the exhaust stack 2.

[0034] In the above embodiment, the control device 34 is realized by commonly available regulators 34a and 34b and calculators 34c and 34d. However, in other embodiments, the control device 34 may be a computer such as a PLC (Programmable Logic Controller), a desktop PC, a laptop PC, a server, or a tablet, and may include components such as a processor (CPU, etc.), a storage device (hard disk, ROM, RAM, etc.), a display device (liquid crystal display, touch panel, etc.), and an input device (keyboard, buttons, touch panel, etc.).

[0035] In this embodiment, the PC 35 is provided separately from the control device 34. The PC 35 may be, for example, a computer such as a PLC, a desktop PC, a laptop PC, a server, or a tablet, and may include components such as a processor, a storage device, a display device, and an input device. For example, the PC 35 may be a PC located adjacent to the control device 34. In another embodiment, the PC 35 may be a PC or tablet of a management company of the furnace 100, located remotely from the control device 34. Furthermore, in another embodiment, the following deterioration status determination function of the PC 35 may be incorporated into the control device 34.

[0036] The PC 35 is communicatively connected to the pressure sensor 31 and receives a signal indicating the furnace pressure. The PC 35 is communicatively connected to the flow meter 13 and receives the flow rate of fuel supplied to the burner 12. The PC 35 is communicatively connected to the first computing unit 34c and receives a first command value for maintaining the furnace pressure at a positive pressure. The PC 35 estimates the deterioration state of sealing elements (e.g., doors, etc.) (not shown) included in the furnace body 1 and the exhaust stack 2 based on the furnace pressure, the fuel flow rate, and the first command value for maintaining the furnace pressure at a positive pressure. For example, the PC 35 may store a table indicating threshold values ​​for the first command value according to the furnace pressure and flow rate. In this case, the PC 35 may read a threshold value from the table according to the received furnace pressure and flow rate, compare the received first command value with the read threshold value, and determine that the sealing elements have deteriorated if the received first command value is greater than the threshold value, i.e., if the opening degree (air flow rate) of the air control valve 33b for maintaining the furnace pressure at a positive pressure is greater than the threshold value. If it is determined that the sealing element is deteriorated, the PC 35 may notify the operator of the deterioration status. For example, the PC 35 may display the deterioration status on a display. Also, for example, the PC 35 may send an email indicating the deterioration status to a registered email address.

[0037] Next, the operation of the furnace pressure control system 3 will be described. First, the operation of the control device 34 will be described.

[0038] Figure 2 is a flowchart showing the operation of the control device 34 in Figure 1. The operation shown in Figure 2 may be repeated, for example, at predetermined intervals (for example, one to several seconds, 10 to several tens of seconds, or one to several minutes) during operation of the furnace 100.

[0039] The furnace pressure regulator 34a receives the furnace pressure from the pressure sensor 31 (step S100).

[0040] Next, the furnace pressure regulator 34a calculates an opening command value so that the difference between the furnace pressure received from the pressure sensor 31 and the target value of the furnace pressure becomes less than a predetermined threshold value (step S102).

[0041] Next, the furnace pressure regulator 34a transmits the calculated opening command value to the motor driver D1 and the first computing unit 34c, and adjusts the opening of the damper 21 via the motor driver D1 and the motor M1 (step S104). However, the motor driver D1 converts the received signal into a control signal for the motor M1 at a preset ratio, and adjusts the rotational drive of the motor M1.

[0042] Next, the first computing unit 34c converts the signal from the furnace pressure regulator 34a based on a preset ratio and calculates a first command value for maintaining the furnace pressure at a positive pressure (step S106). The first computing unit 34c transmits the calculated first command value to the second computing unit 34d and the PC 35.

[0043] Next, the exhaust gas temperature regulator 34b receives the temperature of the exhaust gas from the temperature sensor 32 (step S108).

[0044] Next, the exhaust gas temperature regulator 34b calculates a second command value for adjusting the temperature of the exhaust gas so that the difference between the exhaust gas temperature received from the temperature sensor 32 and the target value of the exhaust gas temperature becomes less than a predetermined threshold value (step S110). The exhaust gas temperature regulator 34b transmits the calculated second command value to the second calculator 34d.

[0045] Next, the second computing unit 34d determines whether the first command value is greater than the second command value (step S112).

[0046] If it is determined in step S112 that the first command value is greater than the second command value (YES), the second computing unit 34d transmits the first command value to the motor driver D2, and adjusts the flow rate of air from the nozzle 33a via the motor driver D2, the motor M2, and the air control valve 33b (step S114). After that, the control device 34 ends the series of operations.

[0047] In contrast, if it is determined in step S112 that the first command value is smaller than the second command value (NO), the second computing unit 34d transmits the second command value to the motor driver D2, and adjusts the flow rate of air from the nozzle 33a via the motor driver D2, the motor M2, and the air control valve 33b (step S116).Then, the control device 34 ends the series of operations.

[0048] Next, the operation of the PC 35 will be described.

[0049] Fig. 3 is a flowchart showing the operation of PC 35 in Fig. 1. The operation shown in Fig. 3 is repeated, for example, at predetermined intervals (for example, one to several seconds, 10 to several tens of seconds, or one to several minutes) during operation of furnace 100. Furthermore, when PC 35 is incorporated into control device 34, the operation shown in Fig. 3 may be executed together with the operation shown in Fig. 2.

[0050] The PC 35 receives the furnace pressure from the pressure sensor 31 (step S200).

[0051] Next, the PC 35 receives the flow rate of fuel to the burner 12 from the flow meter 13 (step S202).

[0052] Next, the PC 35 receives a first command value for maintaining the furnace pressure at a positive pressure from the first computing unit 34c (step S204).

[0053] Next, the PC 35 determines whether the sealing element has deteriorated based on the furnace pressure, the fuel flow rate, and the first command value (step S206). For example, the PC 35 may read a threshold value from a table according to the furnace pressure and the flow rate, and determine that the sealing element has deteriorated if the first command value is greater than the threshold value, i.e., if the air flow rate for maintaining the furnace pressure at a positive pressure is greater than the threshold value.

[0054] If it is determined in step S206 that the sealing element has deteriorated (YES), the PC 35 notifies the operator of the deterioration state (step S208), and ends the series of operations.

[0055] If it is determined in step S206 that the sealing element has not deteriorated (NO), the PC 35 ends the series of operations.

[0056] The furnace pressure control system 3 described above includes a pressure sensor 31 installed in the furnace body 1 and detecting the furnace pressure; a temperature sensor 32 installed in the exhaust stack 2 connected to the furnace body 1 and detecting the temperature of the exhaust gas inside the exhaust stack 2; an air supply means 33 installed upstream of the damper 21 in the exhaust stack 2 and supplying air to the inside of the exhaust stack 2; and a control device 34 controlling the operation of the air supply means 33. The control device 34 adjusts the flow rate of air from the air supply means 33 so that the furnace pressure detected by the pressure sensor 31 becomes positive and the temperature detected by the temperature sensor 32 becomes less than a predetermined value. According to this configuration, air is supplied into the exhaust stack 2 so that the furnace pressure detected by the pressure sensor 31 becomes positive. Therefore, even during low combustion, when the flow rate of exhaust gas decreases, a sufficient flow rate of gas (exhaust gas + air) can be supplied into the exhaust stack 2, just as during high combustion, and the furnace pressure can be maintained at a positive pressure. According to this configuration, air is supplied into the exhaust stack 2 so that the temperature detected by the temperature sensor 32 becomes less than a predetermined value. Therefore, the exhaust gas is cooled by the air supplied to the inside of the exhaust stack 2, and therefore it is possible to prevent the damper 21 from being exposed to excessively high-temperature exhaust gas, thereby preventing damage to the damper 21 due to high temperatures.

[0057] Furthermore, in the furnace pressure control system 3, the control device 34 calculates a first command value for making the furnace pressure positive and a second command value for making the temperature of the exhaust gas less than a predetermined value, and adjusts the flow rate of air from the air supply means based on the larger of the first and second command values. According to this configuration, air is supplied into the exhaust stack 2 based on the higher flow rate command value of the first and second command values. Supplying air into the exhaust stack 2 at a higher flow rate can both maintain the furnace pressure and cool the exhaust gas. Therefore, according to this configuration, both the maintenance of the furnace pressure and the cooling of the exhaust gas can be achieved by a simple calculation of comparing the separately calculated first and second command values.

[0058] The furnace pressure control system 3 also includes a flowmeter 13 that detects the flow rate of fuel supplied to the burner 12 and a PC 35 that determines the deterioration status of the sealing elements in the furnace 100 based on the fuel flow rate detected by the flowmeter 13, the furnace pressure detected by the pressure sensor 31, and a first command value. The amount of air required to maintain a positive furnace pressure, i.e., the first command value, depends on the combustion amount, i.e., the flow rate of fuel supplied to the burner 12. Furthermore, if the sealing elements are deteriorated, gas leaks from the furnace body 1. Therefore, if the sealing elements are deteriorated, the first command value is increased to increase the furnace pressure detected by the pressure sensor 31. Therefore, if the sealing elements are deteriorated, the calculated first command value increases even if the fuel flow rate and furnace pressure are the same as when the sealing elements are not deteriorated. In other words, whether the sealing elements are deteriorated can be determined by considering three parameters: the fuel flow rate, the furnace pressure, and the first command value. With the above configuration, these three parameters are taken into account by the PC 35. Therefore, whether the sealing elements are deteriorated can be determined.

[0059] Furthermore, in the reactor pressure control system 3, when it is determined that the sealing element is deteriorated, the PC 35 notifies the operator of the deterioration state. Therefore, the operator can replace the sealing element early, and the decrease in the operating efficiency of the reactor 100 can be suppressed.

[0060] Furthermore, in the furnace pressure control system 3, the temperature sensor 32 is provided downstream of the damper 21 in the exhaust stack 2. With this configuration, the temperature of the exhaust gas is measured downstream of the damper 21. Therefore, the temperature of the exhaust gas can be measured after the exhaust gas has been sufficiently cooled by air supplied from upstream of the damper 21. Therefore, the cooling effect of the air supply means 33 on the exhaust gas can be evaluated more accurately.

[0061] The furnace pressure control method also includes receiving a furnace pressure from a pressure sensor 31 provided in the furnace body 1 (step S100), receiving a temperature of the exhaust gas inside the exhaust stack 2 from a temperature sensor 32 provided in the exhaust stack 2 connected to the furnace body 1 (step S108), and supplying air into the exhaust stack 2 from an air supply means 33 provided upstream of the damper 21 in the exhaust stack 2 so that the furnace pressure detected by the pressure sensor 31 becomes positive and the temperature detected by the temperature sensor 32 becomes less than a predetermined value (steps S112 to S116). With this configuration, as described above, even during low combustion, when the flow rate of the exhaust gas decreases, a sufficient flow rate of gas can be supplied to the exhaust stack 2, as in high combustion, and the furnace pressure can be maintained at a positive pressure. Furthermore, with this configuration, as described above, the exhaust gas is cooled by the air supplied to the exhaust stack 2, thereby preventing the damper from being exposed to excessively high-temperature exhaust gas. This prevents damage to the damper due to high temperatures.

[0062] The furnace pressure control method further includes calculating a first command value for making the pressure positive (step S106) and calculating a second command value for making the temperature of the exhaust gas inside the exhaust stack 2 less than a predetermined value (step S110), and supplying air from the air supply means 33 to the inside of the exhaust stack 2 includes adjusting the flow rate of air from the air supply means 33 based on the larger of the first command value and the second command value (steps S112 to S116). According to this configuration, as described above, it is possible to both maintain the furnace pressure and cool the exhaust gas by a simple calculation of comparing the first command value and the second command value, which are calculated separately.

[0063] The furnace pressure control method further includes receiving the flow rate of fuel supplied to the burner 12 from the flow meter 13 (step S202), and determining the deterioration state of the sealing element in the combustion furnace based on the fuel flow rate detected by the flow meter, the pressure detected by the pressure sensor, and the first command value (step S206). As described above, by taking into account the three parameters of the fuel flow rate, the furnace pressure, and the first command value, it is possible to determine whether the sealing element has deteriorated. Therefore, with this configuration, it is possible to determine whether the sealing element has deteriorated based on these three parameters.

[0064] The method for controlling the reactor pressure further includes, when it is determined that the sealing element is deteriorated, notifying an operator of the deterioration state (step S208). Therefore, the operator can repair or replace the sealing element early, and a decrease in the operating efficiency of the reactor 100 can be suppressed.

[0065] Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such embodiments. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the claims, and it is understood that such modifications and alterations naturally fall within the technical scope of the present invention. In addition, the steps of the method of the above embodiments do not have to be performed in the order described above, and may be performed in a different order as long as no technical contradiction occurs.

[0066] For example, in the above embodiment, steps S100 to S106 for calculating a first command value for maintaining the furnace pressure at a positive pressure are performed before steps S108 to S110 for calculating a second command value for adjusting the temperature of the exhaust gas. However, in other embodiments, steps S100 to S106 may be performed in parallel with steps S108 to S110, or may be performed after steps S108 to S110. [Explanation of symbols]

[0067] 1 Furnace body 2 Exhaust stack 3. Furnace pressure control system 12 Burner 13 Flow meter 21 Damper 31 Pressure Sensor 32 Temperature Sensor 33 Air supply means 34 Control device 100 Combustion furnace 35 PC (deterioration status determination section)

Claims

1. A furnace pressure control system for controlling the pressure inside a furnace body of a combustion furnace, a pressure sensor provided in the furnace body to detect the pressure inside the furnace body; a temperature sensor provided in an exhaust stack connected to the furnace body, the temperature sensor detecting the temperature of the exhaust gas inside the exhaust stack; an air supply means provided in the exhaust stack upstream of the damper and supplying air into the exhaust stack; a control device for controlling the operation of the air supply means; Equipped with the control device adjusts the flow rate of air from the air supply means so that the pressure detected by the pressure sensor becomes a positive pressure and the temperature detected by the temperature sensor becomes less than a predetermined value; The control device calculating a first command value for making the pressure a positive pressure; calculating a second command value for making the temperature less than the predetermined value; adjusting the flow rate of air from the air supply means based on the larger command value of the first command value and the second command value; The furnace pressure control system includes: a flow meter for detecting the flow rate of fuel supplied to the burner; a deterioration state determination unit that determines a deterioration state of a sealing element in the combustion furnace based on the flow rate of the fuel detected by the flow meter, the pressure detected by the pressure sensor, and the first command value; Further provided with Furnace pressure control system.

2. 2. The reactor pressure control system according to claim 1, wherein the deterioration state determining unit notifies an operator of the deterioration state when it is determined that the sealing element is deteriorated.

3. 3. The furnace pressure control system according to claim 1, wherein the temperature sensor is provided downstream of a damper in the exhaust stack.

4. The furnace pressure control system according to any one of claims 1 to 3, The furnace body, an exhaust stack connected to the furnace body; A combustion furnace comprising:

5. A method for controlling the pressure inside a furnace body of a combustion furnace, comprising: receiving a pressure inside the furnace body from a pressure sensor provided in the furnace body; receiving a temperature of the exhaust gas inside the exhaust stack from a temperature sensor provided in the exhaust stack connected to the furnace body; supplying air into the exhaust stack from an air supply means provided upstream of the damper in the exhaust stack so that the pressure detected by the pressure sensor becomes a positive pressure and the temperature detected by the temperature sensor becomes less than a predetermined value; calculating a first command value for making the pressure a positive pressure; calculating a second command value for making the temperature less than the predetermined value; Including, supplying air from the air supply means to the inside of the exhaust stack includes adjusting a flow rate of air from the air supply means based on a larger command value out of the first command value and the second command value; The furnace pressure control method includes: receiving a flow rate of fuel supplied to the burner from a flow meter; determining a deterioration state of a sealing element in the combustion furnace based on the flow rate of the fuel detected by the flow meter, the pressure detected by the pressure sensor, and the first command value; further comprising: Furnace pressure control method.

6. 6. The method for controlling an in-reactor pressure according to claim 5, further comprising notifying an operator of a deterioration state when it is determined that the sealing element is deteriorated.

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