JP2001041414A - Inner temperature controller for circulating fluidized- bed combustor and operating method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enlarge the available fuel properties by providing an air nozzle for forming a moving layer by introducing particles cooled through a moving layer heat exchanger into a furnace and then moving the particles downward in the moving layer heat exchanger. SOLUTION: An air diffusion nozzle 22 is connected with a fluidization air supply pipe 29 branched from a fluidization air supply pipe 10 and provided with an on/off valve 28 in the way thereof and a duct air nozzle 24 is connected with a fluidization air supply pipe 31 branched from the fluidization air supply pipe 10 and provided with an on/off valve 30 in the way thereof. An air nozzle 27 for forming a moving layer is connected with the fluidization air supply pipe 10 which is provided with an on/off valve 32 on the downstream side of branch point of the fluidization air supply pipe 31. According to the arrangement, available fuel properties can be enlarged and the inner temperature regulation range of a furnace can be enlarged while protecting the heat transfer tubes against wear or burning.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a furnace temperature control apparatus for a circulating fluidized bed combustion apparatus and a method for operating the same.

[0002]

2. Description of the Related Art In general, a conventional circulating fluidized bed combustion apparatus includes:
As shown in FIG. 5, an air distribution nozzle 2 is provided at the bottom of the furnace 1 formed by the water-cooled furnace wall 1a.
A bed material 3 made of ash, limestone, or the like is supplied with fuel such as coal or refuse solidified fuel injected into the air dispersion nozzle 2 by primary air A blown from the air dispersion nozzle 2.
At the same time, it is burned while being fluidized to generate steam to be supplied to a power generation steam turbine (not shown).

The primary air A blown from the air distribution nozzle 2 is supplied by the operation of a fan 5 through a primary air line 4 connected to the bottom of the furnace 1.

Further, a cyclone 6 is connected to an upper portion of the furnace 1 so as to guide exhaust gas generated by combustion in the furnace 1, and particles blown up by the exhaust gas are collected by the cyclone 6. , The cyclone 6
The particles collected in the furnace 1 from the dipleg 7 connected to the lower part of the cyclone 6 through the loop seal 8
It is returned to the bottom and is circulated.

Here, in consideration of the fact that the pressure in the lower part of the furnace 1 is generally higher than the pressure in the lower part of the cyclone 6 of the loop seal 8, in this state, the exhaust gas in the furnace 1 It is formed in a so-called siphon shape so as to prevent particles from flowing into the dipleg 7 below the cyclone 6 and to ensure that the particles separated by the cyclone 6 can flow down into the furnace 1 and return. At the bottom of the loop seal 8, for example, a flow air supply pipe 10 branched from the primary air line 4 and provided with a flow control valve 9 in the middle thereof is connected. By performing the opening adjustment, the flow air C is introduced from the flow air supply pipe 10 to the bottom of the loop seal 8, and some of the particles collected by the cyclone 6 flow in the loop seal 8. It is adapted to be returned to the furnace 1.

On the other hand, the exhaust gas from which the particles have been separated by the cyclone 6 is supplied to the rear heat transfer section 1 having a superheater, a economizer and the like.
In FIG. 1, heat is recovered, and then flows out to an exhaust gas line 12, and is discharged from a chimney to the atmosphere through an air preheater, a dust collector, and the like, not shown.

A secondary air line 13 is connected to a vertically intermediate portion of the furnace 1 so that a secondary air B is supplied by the operation of a fan 14. Furnace 1 from two systems of secondary air line 13
By supplying combustion air to the furnace, generation of NOx is suppressed, and by supplying secondary air B into the furnace 1 from the secondary air line 13, the combustion of unburned components is promoted.

By the way, in the case of a circulating fluidized bed combustion apparatus as shown in FIG. 5, in-furnace desulfurization can be performed.
The combustion temperature in the furnace 1 is often planned in the range of about 800 to 900 [° C.], and even when the furnace is not desulfurized, the combustion temperature in the furnace 1 is about 950 [° C.] or less. Be planned.

Conventionally, when the temperature inside the furnace is controlled in the circulating fluidized bed combustion apparatus as described above, for example, the furnace wall 1a
The range of application of the heat insulating material (not shown) to be cast inside is adapted to the fuel characteristics, or the distribution of the flow rates of the primary air A and the secondary air B is changed.

Further, as shown in FIG. 6, an external heat exchanger 15 is provided to cool a part of particles recirculated into the furnace 1.

The external heat exchanger 15 is provided with a seal box 17 in the middle of a duct 16 branched from the bottom of the loop seal 8 and connected to the furnace 1. Box 19 for blowing air upward from the air distribution plate 18, a flow air supply pipe 20 branched from the flow air supply pipe 10 is connected to the wind box 19, A heat transfer tube 21 for cooling circulating particles and for superheating steam flowing in the heat transfer tube is provided in the upper seal box 17. or,
Similar to the loop seal 8, the seal box 17 of the external heat exchanger 15 is formed in a siphon-like shape so that particles can be reliably returned to the furnace 1 while preventing backflow from the furnace 1. It is.

In the circulating fluidized bed combustion apparatus shown in FIG. 6, fuel is burned while fluidized together with the bed material 3 by the primary air A blown out from the air dispersion nozzle 2 in the furnace 1, and burned in the furnace 1. The particles blown up by the exhaust gas generated by the cyclone 6 are collected by the cyclone 6, and the particles collected by the cyclone 6 are introduced from the dipleg 7 connected to the lower part of the cyclone 6 into the external heat exchanger 15, After being bubbled by the flowing air D in the heat exchanger 15, the heat is removed by heat exchange with the heat transfer tube 21 and cooled, the heat is returned to the bottom of the furnace 1 through the duct 16 and circulated. The flow air C is introduced from the flow air supply pipe 10 to the loop seal 8 by adjusting the opening of the flow control valve 9 in response to
A part of the particles collected in step (1) is returned directly to the furnace 1 without passing through the external heat exchanger 15, whereby the cooling amount of the particles in the external heat exchanger 15 is appropriately adjusted.

[0013]

However, in order to control the temperature inside the furnace, as described above, the furnace wall 1a
It is assumed that the application range of the heat-insulating material to be cast on the inside is in accordance with the fuel characteristics. (If a fuel with a low calorific value is used as the planned fuel, the heat-insulating material must be used to maintain the furnace temperature without lowering it. In contrast, if a fuel with a high calorific value is used as the planned fuel, the area of the heat insulating material will be reduced to prevent the temperature inside the furnace from rising too much.) It has a drawback that it is difficult to use fuels (especially those having different calorific values). For example, when a fuel having a higher calorific value than the planned fuel is used, the heat insulating material installed on the inside of the furnace wall 1a with an area corresponding to the planned fuel has a too large area, and the water and water generated through the furnace wall 1a are too large. The amount of heat exchange with the steam decreases, and the temperature inside the furnace increases.

Further, as mentioned above, changing the distribution of the flow rates of the primary air A and the secondary air B has a disadvantage that the adjustment range of the furnace temperature is narrow. For example, when changing the load of the combustion device, it is necessary to maintain the flow state in the furnace, which is a constraint, and the temperature inside the furnace can be changed to the vicinity of the plan only by changing the flow distribution of the primary air A and the secondary air B. Can not be maintained.

Further, as described above, when the external heat exchanger 15 is installed to cool a part of the particles to be recirculated into the furnace 1, the particles are brought into a bubbling state in the external heat exchanger 15. As a result, the relative speed between the heat transfer tube 21 and the particles is large, and the heat transfer tube 21 has a drawback of severe wear. Further, the heat transfer tube 21 installed in the external heat exchanger 15 is usually a superheated steam tube. It is necessary to provide a bypass line that bypasses the replacement unit to prevent the heat transfer tube 21 from burning. or,
In order to switch the particles from the dipleg 7 below the cyclone 6 to the loop seal 8 side or to the external heat exchanger 15 side, there is a type in which a mechanical part such as a damper is provided. In some cases, wear of the mechanical parts was severe.

In some cases, a wall-shaped heat transfer surface (not shown) is installed in the furnace 1 to control the temperature inside the furnace. There was a drawback that maintenance of the heat transfer surface became severe due to severe wear of the heat transfer surface.

According to the present invention, in view of such circumstances, the usable fuel properties can be expanded, and the range of adjusting the furnace temperature can be expanded while preventing wear and burnout of the heat transfer tubes. A circulating fluidized bed combustion apparatus that can eliminate the need for providing mechanical parts such as a damper for switching particles, and can further improve maintainability by minimizing the wall-like heat transfer surface provided in the furnace. And a method of operating the same.

[0018]

SUMMARY OF THE INVENTION The present invention is directed to a furnace for burning while fuel is fluidized together with bed material by primary air blown out from an air distribution nozzle, and an exhaust gas generated by combustion in the furnace. A cyclone for collecting particles contained in the exhaust gas, wherein the temperature control device in the furnace of the circulating fluidized bed combustion apparatus, wherein the particles collected by the cyclone are returned to the furnace. The particles collected in the step are guided through the dipleg, and a loop seal for returning the particles to the furnace while preventing the particles from flowing back from the furnace, and a particle disposed at the bottom of the loop seal to fluidize the particles. An air dispersing nozzle for causing the air to flow into the furnace, a duct branched from the upper end of the loop seal and connected to the furnace, and a duct connected to the loop seal and connected to the loop. A duct air nozzle for guiding particles from the dip-leg of Ron to the duct side, and a moving bed heat exchanger provided in the middle of the duct for exchanging heat with the heat transfer tube while moving the particles downward to cool the particles. And a moving bed disposed in a duct below the moving bed heat exchanger for guiding particles cooled by the moving bed heat exchanger into the furnace and moving the particles in the moving bed heat exchanger downward. The present invention relates to an in-furnace temperature control device for a circulating fluidized bed combustion device, comprising a forming air nozzle.

In the furnace temperature control device of the circulating fluidized bed combustion apparatus, the supply of air from the air distribution nozzle to the loop seal is stopped, and air is supplied from the air nozzle for duct into the duct. , The particles from the cyclone dipleg are fluidized in the duct and transported above the moving bed heat exchanger, and the particles transported above the moving bed heat exchanger are moved from the moving bed forming air nozzle. By supplying air into the duct below the bed heat exchanger, it was cooled down by being exchanged with the heat transfer tube while being moved downward in the bed heat exchanger, and cooled by the bed heat exchanger. In the moving bed operation mode in which the particles are introduced into the furnace, and with the supply of air from the duct air nozzle and the moving bed forming air nozzle stopped, air is supplied from the air distribution nozzle to the bottom of the loop seal. By supplying, it can be operated to switch the moving layer stop mode in which particles from the dipleg of the cyclone and are fluidized in a loop seal leading to the furnace on-off manner.

According to the above means, the following effects can be obtained.

In the furnace temperature control apparatus for a circulating fluidized bed combustion apparatus according to the present invention, when operating in the moving bed operation mode, the supply of air from the air distribution nozzle into the loop seal is stopped. When air is supplied from the air nozzle into the duct, particles from the cyclone dipleg are fluidized in the duct and transported above the moving bed heat exchanger, and the particles transported above the moving bed heat exchanger Is
When air is supplied from the air nozzle for forming the moving bed into the duct below the moving bed heat exchanger, the air moves and moves downward in the moving bed heat exchanger, exchanges heat with the heat transfer tubes, and is cooled. The particles cooled in the heat exchanger are guided into the furnace.

On the other hand, when the operation is performed in the moving bed stop mode, air is supplied from the air distribution nozzle to the bottom of the loop seal while the supply of air from the duct air nozzle and the moving bed forming air nozzle is stopped. Then, particles from the cyclone dipleg are fluidized in the loop seal and guided into the furnace.

Here, if a fuel having a lower calorific value is used as a planned fuel and the furnace temperature at that time falls within the optimum furnace temperature range, if a fuel having a higher calorific value than the planned fuel is used, If a moving bed heat exchanger is not installed, the furnace temperature rises and deviates from the optimum furnace temperature range.On the other hand, a fuel with a high calorific value is used as the planned fuel. If the internal temperature is controlled to be within the optimum furnace temperature range, if a fuel with a lower calorific value is used than the planned fuel, the furnace temperature will drop if a moving bed heat exchanger is not installed. Although it deviates from the optimum furnace temperature range, in the present invention, when using a low calorific value fuel, operate in the moving bed stop mode, when using a high calorific value fuel, By operating in the moving bed operation mode, Even if the calorific value of the fuel changes, the furnace temperature can be kept within the optimum furnace temperature range, operation restrictions when using fuel other than the planned fuel are improved, and usable fuel properties are expanded. The Rukoto.

If the furnace temperature falls within the optimum furnace temperature range while the load is somewhat high, and if the load is reduced, if the moving bed heat exchanger is not installed, Although the furnace temperature decreases and deviates from the optimum furnace temperature range, in the present invention, when the load is low, the operation is performed in the moving bed stop mode, and when the load is high, the operation is performed in the moving bed operation mode. Then, even if the load changes, the furnace temperature can be kept within the optimum furnace temperature range, and the load range is expanded.

Further, in the moving bed heat exchanger, the particles are not in a bubbling state, and are cooled by exchanging heat with the heat transfer tubes while moving downward, so that the relative speed between the heat transfer tubes and the particles is small. The wear of the heat transfer tube is slight, so that the life of the heat transfer tube is extended and the maintainability is improved. The heat transfer tube installed in the moving bed heat exchanger may be a water-cooled tube through which water flows or a superheated steam tube. If the operation is performed in the moving bed stop mode at the time of startup in which the heat transfer tube cannot be secured, it is possible to prevent the heat transfer tube from being burned without providing a bypass line that bypasses the heat exchange section of the heat transfer tube. Also, there is no need to provide mechanical parts such as dampers to switch between guiding the particles from the dipleg under the cyclone to the loop seal side or to the moving bed heat exchanger side. Not at all.

In the case where a wall-shaped heat transfer surface is installed in a furnace in order to control the furnace temperature, as in the present invention,
If the moving bed heat exchanger is provided, the wall-shaped heat transfer surface can be made small, the wear of the wall-shaped heat transfer surface is reduced, and the maintenance becomes easy.

Furthermore, if the moving bed operation mode and the moving bed stop mode are switched on / off as in the present invention, the flow rate control of the particles is not required, and the control is not complicated, and the control is not complicated. It becomes simple.

[0028]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 show an example of an embodiment of the present invention. In the drawings, the portions denoted by the same reference numerals as those in FIGS. 5 and 6 represent the same components. 5 and 6 is the same as the conventional one, but the feature of the illustrated example is that, as shown in FIG. 1, the particles collected by the cyclone 6 are guided through the dipleg 7, A loop seal 8 for returning the particles into the furnace 1 while preventing backflow from the furnace 1, and an air dispersion disposed at the bottom of the loop seal 8 for fluidizing the particles and guiding the particles into the furnace 1. A nozzle 22, a duct 23 branched from the upper end of the loop seal 8 and connected to the furnace 1, and a duct 23 disposed at a connection portion of the duct 23 to the loop seal 8, for discharging particles from the dipleg 7 of the cyclone 6 to the duct Air duct for duct to lead to 23 side , A moving bed heat exchanger 26 provided in the middle of the duct 23, for exchanging heat with the heat transfer tube 25 while moving particles downward, and for cooling, and a duct below the moving bed heat exchanger 26. 23, a moving bed forming air nozzle 27 for guiding particles cooled in the moving bed heat exchanger 26 into the furnace 1 and moving the particles in the moving bed heat exchanger 26 downward. It is in the point.

The air distribution nozzle 22 is connected to a flow air supply pipe 29 branched from the flow air supply pipe 10 and provided with an on-off valve 28 in the middle. A flow air supply pipe 31 branched from the air supply pipe 10 and provided with an on-off valve 30 in the middle thereof, and the flow air supply pipe 10 connected to the moving layer forming air nozzle 27; An on-off valve 32 is provided downstream of the branch point of the flow air supply pipe 31 in the flow air supply pipe 10.

In the illustrated example, as shown in FIG. 1, the on-off valve 28 is closed, and the supply of air from the air distribution nozzle 22 into the loop seal 8 is stopped.
0, and air is supplied from the duct air nozzle 24 into the duct 23 so that the particles from the dipleg 7 of the cyclone 6 are fluidized in the duct 23 and conveyed above the moving bed heat exchanger 26. The particles transported above the moving bed heat exchanger 26 are supplied with air from the air nozzle 27 for forming the moving bed into the duct 23 below the moving bed heat exchanger 26 by opening the on-off valve 32. A moving bed operation mode in which the particles are cooled by exchanging heat with the heat transfer tubes 25 while moving downward in the moving bed heat exchanger 26, and the particles cooled by the moving bed heat exchanger 26 are introduced into the furnace 1; FIG.
As shown in the figure, the on-off valve 30 and the on-off valve 32 are closed, and the air nozzle 24 for the duct and the air nozzle 27 for forming the moving layer are closed.
In a state where the supply of air from the air is stopped, the on-off valve 28 is opened, and air is supplied from the air distribution nozzle 22 to the bottom of the loop seal 8 to flow particles from the dipleg 7 of the cyclone 6 in the loop seal 8 Furnace 1
The moving layer stop mode for guiding the inside into and out is switched on and off.

Next, the operation of the illustrated example will be described.

When operating in the moving bed operation mode as shown in FIG. 1, the on-off valve 28 is closed and the air distribution nozzle 2 is closed.
In a state where the supply of air from the second to the loop seal 8 is stopped, when the on-off valve 30 is opened and air is supplied from the duct air nozzle 24 into the duct 23, particles from the dipleg 7 of the cyclone 6 The fluidized bed is conveyed above the moving bed heat exchanger 26,
The particles conveyed above 6 open the on-off valve 32 and supply air from the moving-bed forming air nozzle 27 into the duct 23 below the moving-bed heat exchanger 26. The particles are cooled by the heat exchange with the heat transfer tubes 25 while moving downward, and the particles cooled by the moving bed heat exchanger 26 are introduced into the furnace 1.

On the other hand, when operating in the moving bed stop mode as shown in FIG. 2, the on-off valve 30 and the on-off valve 32 are closed, and the air from the duct air nozzle 24 and the moving bed forming air nozzle 27 are discharged. When the supply is stopped, the on-off valve 28 is opened, and air is supplied from the air distribution nozzle 22 to the bottom of the loop seal 8. Particles from the dipleg 7 of the cyclone 6 fluidize in the loop seal 8 and enter the furnace 1. Be guided.

Here, as shown in FIG. 3, when a fuel having a low calorific value is used as the planned fuel, and the furnace temperature at that time falls within the optimum temperature range for the desulfurization, the calorific value is lower than the planned fuel. If a high fuel is used, if the moving bed heat exchanger 26 is not installed, the furnace temperature rises and deviates from the optimum furnace temperature range for desulfurization as shown by the upper broken line in FIG. On the other hand, conversely, if a fuel with a high calorific value is used as a planned fuel and the furnace temperature at that time falls within the optimum temperature range for desulfurization, a fuel with a lower calorific value than the planned fuel is used. However, if the moving bed heat exchanger 26 is not installed, as shown by the lower dashed line in FIG. 3, the furnace temperature decreases and deviates from the desulfurization optimum furnace temperature range. In the illustrated example, when using fuel with a low calorific value, When the operation is performed in the bed stop mode and a fuel having a high calorific value is used, if the operation is performed in the moving bed operation mode, the calorific value of the fuel changes as shown by a solid line in FIG. However, it becomes possible to keep the furnace temperature within the optimum furnace temperature range for desulfurization, the operation restrictions when using fuel other than the planned fuel are improved, and the usable fuel properties are expanded.

As shown in FIG. 4, when the furnace temperature is set within the optimum furnace temperature range for desulfurization under a condition where the load is somewhat high, if the load is reduced, the moving bed heat exchanger 26 is temporarily switched If not installed, as shown by the dashed line in FIG. 4, the furnace temperature decreases and deviates from the optimum furnace temperature range for desulfurization. If the operation is performed in the moving bed operation mode for a high load, as shown by a solid line in FIG. And the load range is expanded.

Further, in the moving bed heat exchanger 26, the particles are not in a bubbling state but exchange heat with the heat transfer tube 25 while moving downward and are cooled, so that the relative speed between the heat transfer tube 25 and the particles is reduced. Is small, the wear of the heat transfer tube 25 is small, the life of the heat transfer tube is extended, and the maintenance property is improved.
A heat transfer tube 25 installed in the moving bed heat exchanger 26
Can be a water-cooled pipe through which water flows or a superheated steam pipe. However, if the heat transfer pipe 25 is a superheated steam pipe, the operation is performed in the moving bed stop mode at the time of startup when the steam flow cannot be secured. For example, burning of the heat transfer tube 25 can be prevented without providing a bypass line that bypasses the heat exchange section of the heat transfer tube 25. Further, there is no need to provide a mechanical part such as a damper in order to switch between guiding the particles from the dipleg 7 below the cyclone 6 to the loop seal 8 side or guiding the particles to the moving bed heat exchanger 26 side. There is no worry about wear.

In the case where a wall-shaped heat transfer surface (not shown) is installed in the furnace 1 in order to control the temperature inside the furnace, a moving bed heat exchanger 26 is provided as in the illustrated example. In this case, the wall-shaped heat transfer surface can be reduced,
Wear of the wall-shaped heat transfer surface is reduced, and maintenance is facilitated.

In addition, in the case of the illustrated example, the flow rate control of the particles is not performed, and the moving bed operation mode and the moving bed stop mode are switched on / off. Be simple.

In this manner, usable fuel properties can be expanded, and the range of adjusting the furnace temperature can be increased while preventing wear and burnout of the heat transfer tube 25.
Also, it is not necessary to provide a mechanical part such as a damper for switching particles, and furthermore, the wall-like heat transfer surface provided in the furnace 1 can be minimized to improve maintainability. The control can be easily performed by a simple operation.

The in-furnace temperature control device of the circulating fluidized bed combustion apparatus of the present invention and the method of operating the same are not limited to the above-described illustrated examples, but may be variously modified without departing from the gist of the present invention. Can of course be added.

[0042]

As described above, according to the in-furnace temperature control apparatus for a circulating fluidized bed combustion apparatus and the method of operating the same according to the present invention, the usable fuel properties can be expanded and the heat transfer tubes can be used. The range of adjusting the furnace temperature can be widened while preventing abrasion and burning, and it is not necessary to provide mechanical parts such as a damper for switching particles. It is possible to achieve an excellent effect that the maintenance can be improved by minimizing the surface, and the control can be easily performed by a simple operation.

[Brief description of the drawings]

FIG. 1 is an overall schematic configuration diagram illustrating a moving bed operation mode according to an example of an embodiment of the present invention.

FIG. 2 is an overall schematic configuration diagram illustrating a moving layer stop mode according to an example of an embodiment of the present invention.

FIG. 3 is a conceptual diagram of a furnace temperature control operation when fuel properties are different.

FIG. 4 is a conceptual diagram of a furnace temperature control operation when a load changes.

FIG. 5 is an overall schematic configuration diagram showing an example of the related art.

FIG. 6 is an overall schematic configuration diagram showing another example of the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Furnace 1a Furnace wall 2 Air distribution nozzle 3 Bed material 6 Cyclone 7 Dip-leg 8 Loop seal 10 Flowing air supply pipe 22 Air distribution nozzle 23 Duct 24 Duct air nozzle 25 Heat transfer tube 26 Moving layer heat exchanger 27 Moving layer formation Air nozzle 28 On / off valve 29 Flowing air supply pipe 30 On / off valve 31 Flowing air supply pipe 32 On / off valve A Primary air B Secondary air

Continued on the front page F term (reference) 3K064 AA06 AA08 AA17 AA20 AC06 AE17 BA07 BA15 BA17 BB01 BB07

Claims (2)

[Claims] 1. A furnace for burning while fuel is fluidized together with a bed material by primary air blown from an air dispersion nozzle, and an exhaust gas generated by combustion in the furnace is guided to remove particles contained in the exhaust gas. A cyclone for trapping, wherein the particles collected by the cyclone are returned to the furnace. A loop seal for guiding the particles into the furnace while preventing the particles from flowing back from the furnace, and a loop seal disposed at the bottom of the loop seal for fluidizing the particles and guiding the particles into the furnace. An air distribution nozzle, a duct branched from the upper end of the loop seal and connected to the furnace, and a cyclone dipleg disposed at a connection of the duct to the loop seal. A duct air nozzle for guiding the particles to the duct side, a moving bed heat exchanger provided in the middle of the duct, for exchanging heat with the heat transfer tube while moving the particles downward, and for cooling; An air nozzle for forming a moving bed that is arranged in a duct below the bed heat exchanger and guides particles cooled by the moving bed heat exchanger into the furnace and moves the particles in the moving bed heat exchanger downward. A temperature control device in a furnace of a circulating fluidized bed combustion device, comprising: 2. While the supply of air from the air distribution nozzle to the loop seal is stopped, air is supplied from the duct air nozzle into the duct, so that particles from the cyclone dipleg flow in the duct. And transported above the moving bed heat exchanger. The particles transported above the moving bed heat exchanger are supplied with air from a moving bed forming air nozzle into a duct below the moving bed heat exchanger. A moving bed operation mode in which particles are cooled by exchanging heat with the heat transfer tubes while being moved downward in the moving bed heat exchanger, and the particles cooled by the moving bed heat exchanger are introduced into the furnace; While the supply of air from the air nozzle and the air nozzle for forming the moving layer is stopped, air is supplied from the air distribution nozzle to the bottom of the loop seal, thereby reducing the cyclone dipleg. How the operation of the furnace temperature control device for a particle circulating fluidized bed combustion system of the loop seal in a claim 1 wherein the switched by fluidizing a moving bed stop mode leading to the furnace on-off manner the.