JP2000274969A - Exterior heat exchanger for circulation fluid layer furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To contrive properly to maintain a temperature of fluid to be heated at an outlet of an exterior heat exchanger and control fluid layers in a circulation fluid layer furnace at the same time, in the circulation fluid layer furnace provided on a particle-circulating path for circulating fluid layer-forming particles collected by a particle-collecting mechanism from the same to the inside of the furnace. SOLUTION: This exterior heat exchanger is provided with a heat exchange pipeline 11 provided inside a heat exchanger body 9 so as to enable heat exchange with fluid layer-forming particles P, a fluid-to-be-heated supplying pipeline 10 connected with an inlet side of the heat exchange pipeline 11, a fluid-to-be-heated discharging pipeline 12 connected with an outlet side of the heat exchange pipeline 11, and a branch pipeline 13 connected with the discharging pipeline 12 from the supplying pipeline 10 without passing through the heat exchange pipeline 11 and provided outside the heat exchanger body 9. Distributing amount-adjusting means C are provided for adjusting amounts to be distributed and supplied of fluid F to be heated from the fluid-to-be-heated supplying pipeline 10 to the heat exchange pipeline 11 and the branch pipeline 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an external heat exchanger of a circulating fluidized-bed furnace, and more particularly, to a fluidized bed-forming granule collected by a granule collecting mechanism from a furnace. The present invention relates to an external heat exchanger of a circulating fluidized-bed furnace provided in a granular fluid channel that recirculates inside.

[0002]

2. Description of the Related Art Conventionally, in a circulating fluidized bed furnace, as shown in FIG. 4, exhaust gas G discharged from the furnace and sand as fluidized bed forming particles P are placed on the furnace top 2b of the furnace body 2. And a particle collecting mechanism 6 is connected to a discharge duct 5 for guiding
A loop seal 17 and a branch from the upstream side of the loop seal 17 are diverted to a granule annular flow path 7 for recirculating the fluidized bed forming granules P separated and collected from the exhaust gas G by the granule collecting mechanism 6 into the furnace. An external heat exchanger 8 connected to the branched return line 7A was provided outside. As shown in an external view in FIG. 5, the loop seal 17 is provided with the fluidized bed which is supplied from the granular ring channel 7 and accumulates in the main body container 18 by air diffusion from the circulation air diffusion pipe 19 provided below. The forming granules P are fluidized and circulated into the furnace, and the amount of the fluidized bed forming granules P circulating in the furnace is adjusted by adjusting the amount of air diffused from the circulation diffuser tube 19. It is. The fluidized bed forming particles P descend in the fluid ring channel 7, the discharge line 16 from the external heat exchanger 8, and the particle return line 20 from the loop seal 17. Therefore, the external heat exchanger 8
The amount of reflux of the fluidized-bed forming particles P through the discharge pipe 16 from is controlled by the amount of air diffused from the discharge air diffuser 15 of the external heat exchanger 8, The annular flow rate of the fluidized-bed forming particles P through the reflux path 20 is adjusted by the amount of air diffused from the circulation air diffusion pipe 19 of the loop seal 17. The discharge amount of the fluidized-bed forming particles P from the furnace main body 2 through the discharge duct 5 is
Is adjusted by the amount of air diffused from the air diffusion tube 3 provided in the furnace bottom 2a. That is, each diffused amount determines the degree of fluidization inside each. The amount of the fluidized-bed particles P flowing out from the discharge pipe 16 or the particulate recirculation path 20 is determined by the degree of fluidization.

As shown in FIG. 6, for example, the external heat exchanger 8 is provided with a heat exchange pipe 11 inside a box-shaped heat exchanger body 9.
The fluid to be heated F is circulated between the fluid F to be heated flowing through the heat exchange pipe 11 and the fluidized bed forming particles P collected by the particle collecting mechanism 6 so as to exchange the fluidized bed. It is configured to recover the retained heat of the granules P. The heat exchanger body 9
The granule ring channel 7 is connected to one corner of the upper part, and the discharge line 16 for the fluidized bed forming granules P into the furnace is connected to the upper part of the granular ring channel 7 where it is arranged. It is connected to the corner of the corner. The flow rate of the fluidized-bed forming particles P flowing through the heat exchanger body 9 is adjusted by the amount of air diffused from the discharge air diffuser 15 disposed at the bottom of the heat exchanger body 9.
The amount of air diffused from the exhaust air diffuser 15 is adjusted according to the temperature of the fluid F to be heated at the outlet of the heat exchange pipeline 11. That is, if the temperature of the fluid to be heated F is higher than a predetermined temperature, the amount of air diffusion is reduced to reduce the flow rate of the fluidized bed forming particles P, and the temperature of the fluid to be heated F is higher than the predetermined temperature. If the temperature is also low, the amount of the diffused air is increased, and the flow amount of the fluidized-bed forming particles P is increased. Here, when the amount of air diffused from the discharge air diffuser 15 is increased in order to adjust the amount of the fluidized bed forming particles P supplied to the heat exchanger body 9, the circulation of the loop seal 17 is performed. When the amount of air diffused from the air diffuser 19 is reduced and the amount of air diffused from the discharge air diffuser 15 is reduced, the amount of air diffused from the circulation air diffuser 19 is increased.

On the other hand, the amount of air diffused from the circulation air diffusion pipe 19 of the loop seal 17 is adjusted according to a change in tower pressure in the fluidized bed furnace 1. In other words, if the tower pressure is higher than a predetermined pressure, the density of the fluidized bed forming particles P in the furnace is too high, so that the amount of air diffused from the circulation diffusion pipe 19 is reduced, If the flow rate of the fluidized-bed forming particles P from the seal 17 is reduced and the tower pressure becomes lower than a predetermined pressure, the fluidized-bed forming particles P in the furnace are insufficient. The amount of air diffused from the trachea 19 is increased, and the fluidized bed forming particles P from the loop seal 17 are increased.
This increases the amount of reflux.

[0005] The furnace temperature is usually 850-900 ° C,
The temperature of the fluidized-bed forming particles P collected by the particle collecting mechanism 6 is about 850 ° C. Therefore, after exchanging heat with the fluid F to be heated in the heat exchanger body 9, the discharge pipe 1
The temperature of the fluidized bed forming granules P returned to the furnace from Step 6 is about 60
0 ° C. The temperature of the fluidized bed forming particles P circulated from the loop seal 17 is about 850 ° C. because it is hardly cooled.

[0006]

In the conventional external heat exchanger of the circulating fluidized bed furnace, the granular annular flow path 7 is connected to one upper corner, and the discharge pipe 16 is connected to the upper upper corner. Since it is connected to a diagonal corner with respect to the location of the granular material ring channel 7, for example, as shown in FIG. A stagnation portion S that extends downward is formed at the stagnation portion S. In the stagnation portion S, the heat exchange efficiency between the fluidized bed forming granules P and the fluid to be heated F is extremely low. The volume efficiency of the heat exchanger itself is greatly reduced, and there is a problem that the heat exchanger body 9 becomes bulky. Further, for example, when the temperature in the furnace increases and the amount of circulation of the fluidized bed forming particles P is increased, if the amount of circulation of the fluidized bed forming particles P from the loop seal 17 is increased, As a result of an increase in the amount of the fluidized bed forming particles P that are not cooled, the temperature in the furnace is further increased. In order to avoid this, if the amount of circulation from the loop seal 17 is reduced and the amount of air diffused from the discharge air diffuser 15 is increased, the amount of heat in the heat exchange pipe 11 in the heat exchanger body 9 is reduced. There is a problem that the temperature of the heated fluid F increases and the temperature of the heated fluid F in the heated fluid discharge pipe 12 becomes too high. If the tower pressure in the furnace becomes too high, the fluidized bed-forming particles P
When the amount of air diffused from the circulation air diffusion pipe 19 in the loop seal 17 is reduced, the accumulated amount of the fluidized bed forming particles P in the loop seal 17 is required. Increases, the supply amount of the fluidized bed forming granules P to the external heat exchanger 8 increases,
For this reason, the amount of heat exchanged in the heat exchange pipeline 11 increases, causing a problem that the temperature of the heated fluid F in the heated fluid discharge pipeline 12 rises more than necessary. These problems have a contradictory aspect between the control response in the furnace and the control response in the external heat exchanger in controlling the circulation amount of the fluidized bed-forming particles P in the conventional configuration. Is caused by that. Therefore, the external heat exchanger of the circulating fluidized bed furnace of the present invention solves the above-mentioned problems, and simultaneously maintains the temperature of the fluid to be heated at the outlet of the external heat exchanger at the same time. An object of the present invention is to appropriately control a fluidized bed in a furnace.

[0007]

Means for Solving the Problems The first characteristic structure of the external heat exchanger of the circulating fluidized bed furnace of the present invention for the above purpose is a fluidized bed. A heat exchange pipe arranged in the heat exchanger body so as to be able to exchange heat with the formed granules, a fluid supply pipe to be heated connected to an inlet side of the heat exchange pipe, and an outlet of the heat exchange pipe The heated fluid discharge pipeline connected to the side, the heated fluid supply pipeline is connected to the heated fluid discharge pipeline without passing through the heat exchange pipeline,
Providing a branch pipe disposed outside the heat exchanger body,
The present invention is characterized in that distribution amount adjusting means for adjusting the distribution and supply amount of the heated fluid from the heated fluid supply pipeline to the heat exchange pipeline and the branch pipeline is provided. [Function and Effect of First Characteristic Configuration] According to the first characteristic configuration, the temperature of the heated fluid in the heated fluid discharge pipe can be adjusted independently of the heat exchange amount in the heat exchanger.
The fluidized bed in the circulating fluidized bed furnace can always be controlled to appropriate conditions. That is, since the fluid to be heated flowing through the branch pipe provided outside the heat exchanger main body maintains the temperature in the pipe to be heated, the heat transfer amount in the heat exchange pipe is excessive, for example. In the case, the supply amount of the fluid to be heated to the branch pipe line is adjusted by the distribution amount adjusting means,
At the outlet of the heat exchange conduit, a low-temperature heated fluid from the branch conduit, which maintains the temperature in the heated fluid supply conduit, is mixed at the outlet of the heat exchange conduit while maintaining the cooling of the fluidized bed forming granules. Thus, the temperature of the fluid to be heated at the outlet can be maintained at a predetermined temperature. In addition, since the fluidized bed forming particles cooled by contact with the heat exchange pipe are recirculated into the furnace, the temperature in the furnace can be appropriately maintained. Therefore, even in the case where the circulation amount of the fluidized bed forming granules is controlled so that the fluidized bed in the furnace can be appropriately maintained as in the conventional configuration, the temperature of the fluid to be heated downstream of the external heat exchanger can be reduced. Can be maintained properly.

[Second feature configuration] A second feature configuration of the external heat exchanger of the circulating fluidized bed furnace of the present invention for the above purpose is as described in claim 2, wherein the heat exchange in the first feature configuration is performed. The present invention is characterized in that a heating fluid addition mechanism that can add a heating fluid at a temperature lower than the heating fluid in the pipeline is provided in the pipeline. [Function and Effect of Second Feature Configuration] According to the second feature configuration, in addition to the function and effect of the first feature configuration, the amount of heat exchange in the external heat exchanger can be controlled independently. That is, since the temperature of the heated fluid on the downstream side of the heated fluid addition mechanism can be reduced, as a result, the temperature of the fluidized bed forming particles refluxed from the external heat exchanger can be further reduced. In addition, it is possible to prevent an abnormal increase in temperature of the fluidized bed forming particles at the heat exchange pipe outlet while suppressing an abnormal increase in temperature in the furnace. Further, the fluidized bed forming particles to which the fluid to be heated undergoes heat exchange are generally formed of sand particles, and have a large heat capacity as compared to the fluid to be heated, which is generally water vapor. Since the temperature of the fluid to be heated can be easily increased, it is possible to increase the amount of the fluid to be heated in the heated fluid discharge pipe.

[Third characteristic configuration] A third characteristic configuration of the external heat exchanger of the circulating fluidized bed furnace of the present invention for the above purpose is as described in claim 3 above. Is provided with a heated fluid addition mechanism capable of adding a heated fluid at a lower temperature than the heated fluid in the pipeline. [Function and Effect of Third Feature Configuration] According to the third feature configuration, in addition to the function and effect of any of the first and second feature configurations, the temperature of the fluid to be heated in the heated fluid discharge pipe is independently controlled. Can be adjusted. In other words, even if the fluid to be heated at the outlet of the heat exchange pipe and the fluid to be heated from the branch pipe are still mixed and the temperature of the fluid to be heated after mixing is too high, the temperature of the fluid to be heated is also increased. Since the temperature can be lowered by the fluid to be heated, the temperature of the fluidized bed forming particles flowing back into the furnace can be lowered, and abnormal temperature rise in the furnace can be prevented.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the external heat exchanger of the circulating fluidized bed furnace of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration explanatory view showing an example of a circulating fluidized bed furnace provided with an external heat exchanger according to the present invention, and FIG. 2 is a perspective view of the circulating fluidized bed furnace shown in FIG.
Note that, in the above-described conventional technology, the same elements as those described with reference to FIGS. 4 to 7 and elements having the same functions are denoted by the same reference numerals as those in FIGS. A part of the detailed description is omitted.

As shown in FIG. 1, for example, a circulating fluidized-bed furnace has a vertical furnace body 2 for forming a fluidized bed in a tower, and a furnace bed 2a has a fluidized bed-forming particle P in the tower. And a discharge duct 5 for discharging the exhaust gas G burned in the furnace together with the fluidized bed forming particles P is provided at the furnace top 2b. A water pipe wall 4 is formed above the water pipe to form a waste heat boiler. The discharge duct 5 is connected to a particle collection mechanism 6 composed of a cyclone that separates the accompanying fluidized bed forming particles P from the discharged exhaust gas G. Furthermore, the fluidized-bed forming particles P collected by the particle collecting mechanism 6 are recirculated from the particle collecting mechanism 6 into the furnace. And an external heat exchanger 8 connected to a branch ring channel 7A branched from the granular ring channel 7 on the upstream side of the loop seal 17. The external heat exchanger 8
Is provided with a heat exchange pipe 11 arranged in the heat exchanger body 9 so as to be able to exchange heat with the fluidized bed forming particles P. The lower end of the external heat exchanger 8 is configured in the same manner as the loop seal 17, and the amount of fluidized bed forming particles P discharged from the discharge pipe 16 is determined by the amount of air diffused from the discharge air diffuser 15. Therefore, the flow rate of the fluidized bed forming particles P flowing through the external heat exchanger 8 is determined by the amount of air diffused from the discharge air diffuser 15. Further, the loop seal 17 is provided with a circulation air diffuser 19 at the bottom of the main body container 18.
The air diffuser 1 for circulation of the loop seal 17 is provided.
The amount of the fluidized-bed forming particles P that recirculates into the furnace from the particle ring channel 20 with the amount of air diffused from the nozzle 9 is configured to be adjustable. Sand particles are used as the fluidized bed forming particles P. The entire reflux amount of the fluidized bed forming particles P into the furnace is adjusted by adjusting the amount of air diffused from each of the exhaust diffuser 15 and the circulation diffuser 19.

The specific structure of the fluidized-bed furnace 1 will be described below. As shown in FIG. 2, the fluidized-bed furnace 1 is continuous below a cyclone which is a particle collecting mechanism 6 connected to a discharge duct 5 of the furnace body 2. A granular ring channel 7 is provided outside the furnace main body 2, and the granular ring channel 7 is connected to an upper portion of the main body container 18 of the loop seal 17, and branches off from the granular ring channel 7. The return flow path 7A is connected to the upper part of the heat exchanger body 9, and the lower part of the heat exchanger body 9 is provided with a discharge pipe 16 for discharging the fluidized bed forming particles P toward the furnace. is there. The discharge pipe 16 is connected to the furnace main body 2 so as to recirculate the fluidized bed forming particles P after the heat exchange into the furnace bottom 2 a. The particle return path 20 of the loop seal 17 is connected to the furnace main body 2. 2 above the discharge line 16.
The external heat exchanger 8 is provided so as to function as a superheater of the waste heat boiler, and a supply of a heated fluid connected to an outlet of the waste heat boiler is provided at an inlet side of the heat exchange pipe 11. A pipe 10 is connected, and a heated fluid discharge pipe 12 for supplying steam to a steam turbine of a power generation facility (not shown) is connected to an outlet side of the heat exchange pipe 11 (see FIG. 1).
A branch pipe 13 is arranged outside the heat exchanger body 9 and connected to the heated fluid discharge pipe 12 without passing through the heat exchange pipe 11 from the heated fluid supply pipe 10. Further, the heat exchange pipe 1 is connected to the heated fluid supply pipe 10.
1, a distribution amount adjusting means C for adjusting the distribution and supply amount of the heated fluid F from the heated fluid supply pipe 10 to the branch pipe 13 is provided. Further, the heat exchange pipe line 11 is provided between the collecting can 11b from the upstream pipe group and the distribution can 11a to the downstream pipe group, to be heated at a lower temperature than the steam which is the fluid F to be heated in the pipe line. A first fluid adding mechanism 14A to which a fluid Fc (for example, water) can be added is provided. Further, a second fluid addition mechanism capable of adding a heated fluid Fc (for example, water heated to a saturation temperature) at a temperature lower than the vapor as the heated fluid F in the pipeline to the heated fluid discharge pipe 12. 14B is provided.

As shown in FIG. 2, the external heat exchanger 8 has a particle ring channel 7 connected to the upper end of the heat exchanger body 9. The lower part of the heat exchanger body 9 is connected to a discharge pipe 16 inclined downward. The discharge line 16
Below the side wall portion corresponding to the back surface of the side wall portion to which the fluidized bed forming particles P (that is, sand particles) in the heat exchanger main body 9 are discharged from the discharge line 16, are provided.
5 is arranged. Further, the heat exchange pipe 11 is provided so as to penetrate the side wall portion. The heat exchange line 11 is
The heated fluid supply line 10 is connected to a distribution can 11a for the upstream tube group, and is divided into an upper front tube group and a lower rear tube group. The discharge pipe 12 is connected to the collecting can 11b from the latter pipe group, and the collecting can 11b from the former pipe group is connected to the distribution can 11a to the latter pipe group by the heating fluid addition mechanism 14. Connected via.

The granule ring channel 7 is provided with a sand injection pipe 24 into which room temperature sand can be externally charged as a temperature marker M on the granule layer in the channel, and descends down the granule ring channel 7. A particle flow rate detecting means configured to measure the weight flow rate of the fluidized bed forming particles P is provided. This weight flow rate is representative of the weight of the fluidized bed forming particles P passing through the inside of the external heat exchanger 8 per unit time. From the tower pressure in the furnace and the temperature of the exhaust gas G to the discharge duct 5, a target value of the circulation amount of the fluidized bed forming granules P is set, and the weight measured by the granule flow rate detecting means is set. The respective target values of the amount of air diffused from the exhaust diffuser 15 and the amount of air diffused from the circulation diffuser 19 are set so as to maintain the flow rate at the target value.

The sand injection pipe 24 is disposed at a position slightly higher than the upper surface of the granular layer in the granular annular channel 7 in the operating state of the fluidized bed furnace 1 maintained in a normal state. .
The first temperature detecting means 25 and the second temperature detecting means 26 are arranged vertically below and below a predetermined distance D. Both temperature detecting means 25 and 26 are both constituted by thermocouple thermometers. The sand injection pipe 24 intermittently feeds the normal-temperature sand, sets the normal temperature of the granular layer 21 to the first temperature, and sets the normal-temperature sand to the second temperature, thereby setting the temperature. A marker M is formed. Since the sand has a high heat transfer resistance, the temperature is not immediately averaged even when mixed, so that the sand is divided into regions having different temperatures, and the boundaries can be easily identified.

The two temperature detecting means 25 and 26 normally detect the first temperature (this temperature is almost the same as the exhaust gas temperature of the discharge duct).
4, sand as a temperature marker M is thrown in, and gradually descends to reach a first detection point provided with the first temperature detection means 25 (first time). Detects the second temperature which is the temperature of the temperature marker M. The fluidized bed forming particles P from the particle collecting mechanism 6 fall and accumulate on the sand that is the temperature marker M to form a new interface. Thereafter, the first temperature detecting means 25 again detects the first temperature, and the temperature marker M gradually falls to reach the second detecting point where the second temperature detecting means 26 is provided. (Second time), the second temperature detecting means 26 detects the second temperature. Based on these, the fluidized bed forming particles P obtained from the elapsed time from the first time to the second time and the internal volume of the particle ring channel 7 between the temperature detecting means 25 and 26 are obtained. By calculating and deriving the weight flow rate of the fluidized bed forming granules P passing through the external heat exchanger 8 from the volume flow rate of the fluidized material and the bulk density of the fluidized bed forming granules P, It is measured by.

In the fluidized bed furnace 1 having the above structure,
The fluidized-bed forming particles P discharged from the discharge duct 5 are transferred to the particle return path 2 of the loop seal 17 connected to the particle ring flow path 7.
0, a branch ring channel 7A branched from the granular ring channel 7
Is returned from the discharge pipe 16 of the external heat exchanger 8 connected to the heat exchanger. The amount of recirculation is determined by the amount of air diffused from the exhaust diffuser 15 of the external heat exchanger 8 and the amount of air diffused from the circulation diffuser 19 of the loop seal 17. By adjusting the amount of air diffused from the discharge air diffuser 15 and the amount of air diffused from the circulation air diffuser 19, the amount of the fluidized bed forming particles P flowing back to the furnace body 2 is discharged from the furnace top 2b. In order to properly control the temperature of the superheated steam from the external heat exchanger 8 while balancing the amount of the fluidized bed forming particles P, the amount of air diffused from the discharge air diffuser 15 of the external heat exchanger 8 is adjusted. The amount of air diffused from the circulation air diffuser 19 is adjusted in conjunction with the adjustment. The fluidized bed furnace 1 according to the waste put into the furnace
In, the furnace temperature and the superheated steam temperature are adjusted. For example, when the lower heating value of the waste put into the furnace is the standard, the target value of the circulation amount of the fluidized bed forming granules P is set according to the normally set operating conditions, and the target value of the circulation amount is set. In contrast, the amount of air diffused from the diffuser tube 3 of the furnace body 2, the amount of air diffused from the diffuser tube 15 of the external heat exchanger 8, and the amount of air diffused from the diffuser tube 19 of the loop seal 17. Are set. If the amount of air diffused from the discharge air diffuser 15 is increased, the amount of air diffused from the circulation air diffuser 19 is reduced.

When the low calorific value of the waste introduced into the furnace is high, the temperature of the exhaust gas increases, and accordingly, the exhaust gas is collected by the particulate collection mechanism 6 and is discharged from the external heat exchanger 8. The temperature of the fluidized-bed forming particles P supplied to the container also increases. Therefore, it is necessary to lower the temperature of the fluidized bed-forming particles P flowing back from the particle return passage 20 into the furnace, and also to increase the amount of the returned particles. The target value of the air volume is appropriately increased, and at the same time, the target value of the air volume of the circulation air diffuser 19 is adjusted so as to decrease. However, if the amount of the fluidized bed forming particles P passing through the external heat exchanger 8 is increased in such a manner, the superheat temperature of the steam as the fluid F to be heated which is superheated in the external heat exchanger 8 increases. Because it is too long, water is sprayed and supplied as a low-temperature heated fluid Fc from the first fluid adding mechanism 14A constituting the heated fluid adding mechanism 14 provided between the former stage and the latter stage of the heat exchange pipeline 11 into the pipeline. , While controlling the superheating temperature of the steam in the conduit, and simultaneously forming the fluidized bed forming particles P in contact with the conduit.
Temperature is further reduced. Thus, by lowering the temperature of the fluidized-bed forming particles P from the discharge pipe 16, the temperature of the fluidized-bed forming particles P flowing back into the furnace from the particle recirculating passage 20 is reduced, and the temperature in the furnace is reduced. Adjustment is also possible. Accordingly, the adjustment of the target value of the amount of air diffused by the air diffusers 15 and 19 is appropriately returned to the original value in accordance with the degree of the temperature decrease of the fluidized bed forming particles P. When it is necessary to lower the superheated steam temperature more than necessary for adjusting the furnace temperature,
Apart from adjusting the target value of the amount of air diffused by the two air diffusers 15, 19, the heat exchanger body 9
The distribution amount adjusting means C controls the heat exchange line 11 and the branch line 13 so that a part of the steam is directly sent to the heated fluid discharge line 12 through the branch line 13 disposed outside.
And the amount of steam to be distributed between the two is adjusted. If the superheat temperature is too high even if the steam from both pipes 12 and 13 is mixed in the heated fluid discharge pipe 12, the heated fluid added to the heated fluid discharge pipe 12 is added. Saturated water is sprayed and supplied as low-temperature heated fluid Fc from the second fluid addition mechanism 14B constituting the mechanism 14 into the pipeline, so that the superheated steam can be further cooled.

When the lower heating value of the waste put into the furnace is low, the temperature of the exhaust gas is lowered, and accordingly, the fluidized bed forming particles P supplied to the external heat exchanger 8 are reduced.
Temperature also decreases. In this case, if the temperature in the furnace decreases, the amount of steam generated from the waste heat boiler constituted by the water pipe wall 4 provided in the furnace body 2 also decreases, and the fluidized bed forming particles P in the external heat exchanger 8 are reduced. Is suppressed, but when the temperature in the furnace is lowered, the discharge air diffuser 1
At the same time as reducing the target value of the amount of diffused air of No. 5, adjustment is made so as to increase the target value of the amount of diffused air of the circulation diffuser tube 19 accordingly. In this way, the amount of reflux of the fluidized bed forming particles P cooled in the external heat exchanger 8 is reduced, and at the same time, the amount of reflux of the fluidized bed forming particles P from the loop seal 17 that is not cooled is increased. If the cooling of the fluidized bed forming particles P in the external heat exchanger 8 is suppressed and the temperature of the fluidized bed forming particles P flowing back from the granular particle return passage 20 is increased somewhat, the cooling in the furnace is performed. Thus, the temperature inside the furnace can be maintained. For this purpose, the heat exchange line 1
The amount of steam to be distributed to the branch line 13 and the branch line 13 is adjusted to increase the amount of steam to the branch line 13. As a result, the heated fluid discharge pipe 12 is connected to both pipes 12, 1
If the steam from 3 is mixed, the temperature of the superheated steam may be lowered, but as a countermeasure, another steam superheating means can be provided in the heated fluid discharge pipe 12.

As described above, in the present invention,
The temperature of the heated fluid F discharged from the external heat exchanger 8 via the heated fluid discharge pipe 12 can be maintained at a predetermined temperature while maintaining the temperature in the furnace within a required range.

Next, another embodiment of the present invention will be described. <1> In the above embodiment, the external heat exchanger 8 is
Although an example in which the fluid seal is connected in parallel with the loop seal 17 has been described, for example, as shown in the conceptual diagram of FIG. And the external heat exchanger 8 also serves as the loop seal 17 so that the fluidized bed forming particles P are directly returned to the particle return path 20 by the air diffused from the discharge air diffuser 15. The fluid particles forming the fluidized bed formed by the particle collecting mechanism 6 are recirculated from the particle collecting mechanism 6 into the furnace. Only the external heat exchanger 8 is provided in the annular channel 7, and the external heat exchanger 8 is provided with a heat exchange pipe 11 arranged in the heat exchanger main body 9 so as to be able to exchange heat with the fluidized bed forming granules P. It may be provided. At the lower end of the external heat exchanger 8,
By providing a function equivalent to a loop seal, the air diffuser
And the flow rate of the fluidized bed forming particles P flowing through the external heat exchanger 8 is determined by the amount of air diffused from the circulation diffuser pipe 19, and is returned from the particle return passage 20 into the furnace. The amount of the fluidized-bed forming particles P to be adjusted may be configured to be adjustable. <2> In the above embodiment, the distribution and supply of the heated fluid F from the heated fluid supply line 10 to the heat exchange pipeline 11 and from the heated fluid supply line 10 to the branch pipeline 13 Although the distribution amount adjusting means C for adjusting the amount is illustrated by providing a flow rate control valve in the heat exchange line 11, the configuration of the distribution amount adjusting means C is arbitrary, and other flow rate adjustments are possible. Means may be provided, and the branch pipe 13 may be provided with a flow control means, or the branch pipe 13 may be provided with a flow control means only. <3> In the above-described embodiment, a heated fluid addition mechanism capable of freely adding a heated fluid Fc lower than the heated fluid F in the pipeline between the upstream and downstream stages of the heat exchange pipeline 11. Although the example in which the first fluid adding mechanism 14A as 14 is provided has been described, this is a description of a preferred embodiment, and the heated fluid adding mechanism 14 is provided in the other part of the heat exchange pipe 11. And the first fluid adding mechanism 14A may be omitted. <4> In the above-described embodiment, the heated fluid addition mechanism 14 that can freely add the heated fluid Fc at a lower temperature than the heated fluid F in the heated fluid discharge pipeline 12 to the heated fluid discharge pipeline 12. Although the example in which the two-fluid addition mechanism 14B is provided has been described, this is a description of a preferred embodiment, and the second fluid addition mechanism 14B may be omitted. <5> In the above embodiment, an example in which the exhaust pipe 16 inclined downward is connected to the upper part of the side wall of the heat exchanger body 9 has been described.
May be connected downward from the bottom of the heat exchanger main body 9 so as to drop the fluidized bed forming particles P discharged to the loop seal 17. In this case, the exhaust air diffuser 15 can be omitted. <6> In the above-described embodiment, an example in which the particulate flow rate detecting means is provided in the particulate ring channel 7 has been described. However, this is a description of a preferred embodiment, and The detecting means can be omitted, and the fluidized bed-forming particles P
Without measuring the flow rate of the gas, the amount of air diffused through each of the air diffusers 3, 15, and 19 may be adjusted based on the tower pressure in the furnace, the temperature inside the furnace, and the like.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view of an example of a circulating fluidized bed furnace according to the present invention.

FIG. 2 is a perspective view showing an external appearance of an example of a circulating fluidized bed furnace according to the present invention.

FIG. 3 is a diagram illustrating the configuration of another example of a circulating fluidized bed furnace according to the present invention.

FIG. 4 is a diagram illustrating the configuration of a conventional circulating fluidized bed furnace.

FIG. 5 is a perspective view showing an external appearance of an example of a conventional circulating fluidized bed furnace.

FIG. 6 is a perspective view showing an example of a conventional external heat exchanger.

FIG. 7 is a perspective perspective view illustrating a conventional external heat exchanger.

[Explanation of symbols]

 Reference Signs List 6 fluid collection mechanism 7 granular ring channel 9 heat exchanger main body 10 heated fluid supply pipeline 11 heat exchange pipeline 12 heated fluid discharge pipeline 13 branch pipeline 14 heated fluid addition mechanism C distribution amount adjusting means F Fluid to be heated Fc Fluid to be heated at low temperature P Fluidized bed forming particles

Claims (3)

[Claims] A granular fluid channel (7) for recirculating fluidized bed-formed particles (P) collected by a particle collecting mechanism (6) from the particle collecting mechanism (6) into a furnace. An external heat exchanger of a circulating fluidized bed furnace provided in a heat exchange pipe (11) disposed in a heat exchanger body (9) so as to be able to exchange heat with the fluidized bed forming granules (P). A heated fluid supply pipeline (10) connected to the inlet side of the heat exchange pipeline (11); and a heated fluid discharge pipeline (10) connected to the outlet side of the heat exchange pipeline (11). 12), the heating fluid supply pipe (10) is connected to the heating fluid discharge pipe (12) without passing through the heat exchange pipe (11), and is connected to the outside of the heat exchanger body (9). And a branch pipe (13) arranged in the heat-supplying fluid supply pipe (10) to add heat to the heat exchange pipe (11) and the branch pipe (13). Distributing amount adjusting means (C) an external heat exchanger of the circulating fluidized bed furnace which is provided with which to adjust the dispensing amount of the fluid (F). 2. A heating fluid addition mechanism (14) is provided in the heat exchange pipe (11), to which a heating fluid (F) lower in temperature than the heating fluid (F) in the pipe can be added. An external heat exchanger for a circulating fluidized bed furnace according to claim 1. 3. A heated fluid (F) having a lower temperature than the heated fluid (F) in the heated fluid discharge pipe (12).
The external heat exchanger of a circulating fluidized bed furnace according to claim 1 or 2, further comprising a heated fluid addition mechanism (14) to which c) can be added.