JP2017075714A - Oxygen combustion boiler facility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oxygen combustion boiler facility that inhibits an increase in capacity of a forced draft fan to eliminate the need of additional apparatus for imparting circulation resistance.SOLUTION: In the oxygen combustion boiler facility, a dehydrator 11 for removing water content from an exhaust gas to be recirculated is provided on an inlet side of the forced draft fan 9 in an exhaust gas recirculation line 8R; and a gas gas heater 12 as a heater for heating an exhaust gas on an outlet side of the dehydrator 11 using an exhaust gas on an inlet side of the dehydrator 11 and leading the heated exhaust gas to the forced draft fan 9.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an oxyfuel boiler facility.

  Coal-fired power generation facilities using pulverized coal-fired boilers have come to play an important role due to the situation of rising prices accompanying the recent increase in demand for oil and natural gas. An air-fired boiler using air as a combustion gas has been generally used for conventional pulverized coal fired boilers.

Coal combustion itself has the problem of higher CO ₂ emissions compared to oil and natural gas combustion, so the increase in CO ₂ emissions due to an increase in the dependency ratio on coal thermal power will prevent global warming. From the point of view, this is an important issue that must be avoided.

In air-fired boilers, air is used as a carrier gas and a combustion gas for pulverized coal as a fuel, and the composition thereof is about 80% nitrogen and about 20% oxygen. As a result, since a large amount of nitrogen is contained in the exhaust gas, there is a problem that the work of separating and recovering nitrogen and CO ₂ from the exhaust gas becomes troublesome.

Therefore, oxyfuel boilers have attracted attention and are being developed as a method for greatly reducing CO ₂ emissions into the atmosphere.

In the oxyfuel boiler, most of the exhaust gas discharged from the oxyfuel boiler that burns pulverized coal is extracted from the middle of the flue, and the oxygen concentration is adjusted by mixing the extracted exhaust gas and oxygen produced by an oxygen production apparatus. An exhaust gas recirculation system is employed in which combustion gas is supplied to the oxyfuel boiler. According to oxyfuel combustion boiler of the exhaust gas recirculation system, not included nitrogen in the exhaust gas, CO ₂ concentration in the final exhaust gas to be discharged is increased dramatically, therefore, the separation and recovery work of CO ₂ from the exhaust gas It becomes easy.

  In addition, there exists patent document 1 as what shows the general technical level relevant to an oxyfuel boiler, for example.

JP 2014-59104 A

  By the way, during the oxyfuel combustion operation in the oxyfuel boiler, the exhaust gas is also recirculated as a pulverized coal carrier gas. For this reason, the water | moisture content in the pulverized coal pipe connected to the mill which pulverizes coal becomes high, an acid dew point (temperature which sulfurous acid gas turns into sulfuric acid and condensation) falls, and the possibility of corrosion increases. In addition, if the moisture in the pulverized coal pipe becomes high, the pulverized coal cannot be sufficiently dried, which adversely affects transportation and combustion. Therefore, a dehydrator is provided in the middle of the recirculation line of the pulverized coal transportation gas. Therefore, the dryness of pulverized coal in the mill is improved.

  On the other hand, at the time of air combustion operation in the oxyfuel boiler, air is used as the pulverized coal carrier gas, so that the air is bypassed without passing through the dehydrator. Here, since the dehydrator is a device having a very high pressure loss, the total pressure loss in the carrier gas distribution system varies greatly between the air combustion operation and the oxyfuel combustion operation. As a result, the forced draft fan must have a large capacity, and the flow resistance equivalent to that of the dehydrator is to prevent the exhaust gas recirculated during the oxyfuel combustion operation from flowing only into the combustion gas distribution system. It has been necessary to provide additional equipment such as a damper for imparting the above in the combustion gas distribution system.

  The present invention has been made in view of the above-described conventional problems, and aims to provide an oxyfuel boiler facility that prevents an increase in capacity of a forced air blower and eliminates the need for additional equipment for imparting flow resistance. To do.

The present invention is an oxyfuel boiler facility in which a forced air blower is provided in an exhaust gas recirculation line for recirculating exhaust gas discharged from a boiler as fuel transfer gas and combustion gas,
The present invention relates to an oxyfuel boiler facility in which a dehydrating device is provided at least upstream from the forced air blower and upstream from the air intake during air combustion operation.

In the oxyfuel boiler facility, the dehydrator is provided in an exhaust gas recirculation line on the inlet side of the forced air fan,
It is preferable that a heater that heats the exhaust gas on the outlet side of the dehydrator with the exhaust gas on the inlet side of the dehydrator is provided in the exhaust gas recirculation line on the inlet side of the forced draft fan.

  The oxyfuel boiler equipment preferably includes an auxiliary ventilator provided on the inlet side of the pusher ventilator so as to compensate for the pressure loss of the exhaust gas caused by the dehydrator and the heater.

Further, the oxyfuel boiler equipment includes a branch exhaust gas recirculation line that recirculates the exhaust gas as the transfer gas by the operation of a primary ventilator provided in parallel with the forced draft fan,
It is preferable that the dehydrator is provided in a branch exhaust gas recirculation line on the inlet side of the primary ventilator.

  In the oxyfuel boiler facility, a heater for heating the exhaust gas on the outlet side of the dehydrator by the exhaust gas on the inlet side of the dehydrator may be provided in the branch exhaust gas recirculation line on the inlet side of the primary ventilator. preferable.

  The oxyfuel boiler equipment includes an oxygen production device that supplies oxygen to the combustion gas recirculated by the exhaust gas recirculation line, and the oxygen from the oxygen production device is pushed into the recirculated exhaust gas. It is preferable that the mixing is performed on the inlet side of the ventilator.

  According to the oxyfuel boiler equipment of the present invention, it is possible to achieve an excellent effect that an increase in capacity of the forced draft fan is prevented and an additional device for imparting flow resistance can be made unnecessary.

BRIEF DESCRIPTION OF THE DRAWINGS It is a whole schematic block diagram which shows the 1st Example of the oxyfuel boiler equipment of this invention, Comprising: It is a figure which shows the state at the time of oxyfuel operation. BRIEF DESCRIPTION OF THE DRAWINGS It is a whole schematic block diagram which shows the state at the time of the air combustion driving | operation in the 1st Example of the oxyfuel boiler equipment of this invention. It is a whole schematic block diagram which shows the modification of the 1st Example of the oxyfuel boiler equipment of this invention, Comprising: It is a figure which shows the state at the time of oxyfuel operation. It is a whole schematic block diagram which shows the 2nd Example of the oxyfuel boiler equipment of this invention, Comprising: It is a figure which shows the state at the time of an oxyfuel operation. It is a whole schematic block diagram which shows the state at the time of the air combustion driving | operation in the 2nd Example of the oxyfuel boiler equipment of this invention. It is a whole schematic block diagram which shows the modification of the 2nd Example of the oxyfuel boiler equipment of this invention, Comprising: It is a figure which shows the state at the time of oxyfuel operation. It is a whole outline block diagram which shows an example of general oxyfuel boiler equipment, and is a figure showing the state at the time of oxyfuel operation. It is a whole outline block diagram which shows the state at the time of the air combustion driving | running in an example of general oxyfuel boiler equipment.

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

  1 and 2 show a first embodiment of the oxyfuel boiler equipment of the present invention.

  The oxyfuel boiler equipment shown in FIGS. 1 and 2 includes a boiler 1, a mill 2, preheaters 3 and 4, an exhaust gas cooler 5, a dust removing device 6, an induction fan 7 (IDF), and an exhaust gas line. 8, an exhaust gas recirculation line 8 </ b> R, a forced draft fan 9 (FDF), and an oxygen production apparatus 10.

  The boiler 1 burns fuel with combustion gas to generate steam, and discharges exhaust gas to an exhaust gas line 8. The mill 2 pulverizes coal as the fuel. The preheater 3 preheats the carrier gas introduced into the mill 2 with the exhaust gas discharged from the boiler 1. The preheater 4 preheats the combustion gas with the exhaust gas discharged from the boiler 1. The exhaust gas cooler 5 cools the exhaust gas that has passed through the preheater 4. The dust removing device 6 is a bag filter or an electric dust collector, and collects the dust in the exhaust gas cooled by the exhaust gas cooler 5. In the exhaust gas recirculation line 8R, the exhaust gas in which the dust is collected by the dust removing device 6 is used as the combustion gas for the boiler 1 and the conveying gas for the pulverized coal by the operation of the induction fan 7 and the forced air fan 9. It is designed to recirculate. As shown in FIG. 1, the oxygen production apparatus 10 supplies oxygen to exhaust gas recirculated as combustion gas for the boiler 1.

  In the case of the first embodiment, a dehydrator 11 for removing moisture from the recirculated exhaust gas is provided on the inlet side of the forced draft fan 9 in the exhaust gas recirculation line 8R, and the exhaust gas on the inlet side of the dehydrator 11 is provided. Is provided with a gas gas heater 12 as a heater for heating the exhaust gas on the outlet side of the dehydrator 11. The dehydrator 11 is provided upstream of the air intake 14 (see FIG. 2) during the air combustion operation.

The extraction line 8D is branched from the exhaust gas line 8 on the outlet side of the induction fan 7, and a part of the exhaust gas is sent from the extraction line 8D to the CO ₂ concentration unit.

FIG. 1 shows the state during the oxyfuel combustion operation, while FIG. 2 shows the state during the air combustion operation. In the case of the air combustion operation shown in FIG. 2, as shown by the phantom line, the oxygen production device 10, the dehydration device 11, and the gas gas heater 12 are not used, and air is taken in from the air intake 14 and the boiler 1. The exhaust gas discharged from the exhaust fan 8 is sent from the exhaust gas line 8 on the outlet side of the induction fan 7 through the extraction line 8D to the chimney instead of the CO ₂ concentration unit. Incidentally, the dehydrator 11 and the gas gas heater 12 are provided in the exhaust gas recirculation line 8R on the downstream side of the branch point of the extraction line 8D.

  Next, the operation of the first embodiment will be described.

  The pulverized coal as fuel obtained by finely pulverizing coal in the mill 2 is supplied to the boiler 1 while being dried by the carrier gas preheated by the preheater 3, and is supplied by the combustion gas preheated by the preheater 4 in the boiler 1. It burns and steam is generated by the combustion heat.

  The exhaust gas discharged from the boiler 1 to the exhaust gas line 8 gives heat to the carrier gas when passing through the preheater 3 and further gives heat to the combustion gas when passing through the preheater 4.

During the oxyfuel combustion operation of the oxyfuel boiler facility, the exhaust gas that has passed through the preheater 4 is cooled by the exhaust gas cooler 5, dust is collected by the dust removing device 6, and pressurized by the induction fan 7, and then FIG. As shown in FIG. 4, the dehydrator 11 removes moisture. The exhaust gas from which moisture has been removed by the dehydrator 11 is heated by the exhaust gas on the inlet side of the dehydrator 11 when passing through the gas gas heater 12, and is then guided to the insufflator 9. By the operation, the gas is recirculated from the exhaust gas recirculation line 8R as the combustion gas for the boiler 1 and the conveying gas for the pulverized coal. After the combustion gas is preheated by the preheater 4, oxygen is supplied from the oxygen production apparatus 10 and introduced into the boiler 1. A part of the exhaust gas discharged from the boiler 1 is sent from the exhaust gas line 8 on the outlet side of the induction fan 7 to the CO ₂ concentration unit via the extraction line 8D, and the operation of separating and recovering CO ₂ from the exhaust gas is performed. Done.

On the other hand, during the air combustion operation of the oxyfuel boiler equipment, as shown in FIG. 2, the dehydrator 11 and the gas gas heater 12 are not used, and air is introduced from the inlet side of the forced air blower 9, and the air is Used as a combustion gas for the boiler 1 and a gas for conveying pulverized coal. The air used as the combustion gas is preheated by the preheater 4 and then introduced into the boiler 1 as it is without being supplied with oxygen from the oxygen production apparatus 10. The exhaust gas discharged from the boiler 1 is sent from the exhaust gas line 8 on the outlet side of the induction fan 7 through the extraction line 8D to the chimney instead of the CO ₂ concentration unit, and is released into the atmosphere.

  Incidentally, in the case of a general oxyfuel boiler facility, as shown in FIG. 7, the dehydrator 11 branches from the exhaust gas recirculation line 8 </ b> R on the outlet side of the forced air blower 9 and leads to the preheater 3. -1. In other words, since the dehydrator 11 which is a device having a very high pressure loss exists on the outlet side of the forced air blower 9, it is necessary to make the forced air fan 9 have a large capacity and recirculate during the oxyfuel combustion operation. In order to prevent the exhaust gas to flow only into the combustion gas distribution system, an additional device such as a damper 15 (see the phantom line in FIG. 7) for providing a distribution resistance equivalent to that of the dehydrator 11 is used as the combustion gas. It was necessary to install in the distribution system. Further, the inlet gas temperature of the forced air blower 9 during the oxyfuel combustion operation is about 130 to 150 ° C., whereas the inlet gas (air) temperature of the forced air blower 9 during the air combustion operation (see FIG. 8) is The temperature is substantially equal to the atmospheric temperature and is about 30 ° C. For this reason, with respect to the inlet gas temperature of the forced air blower 9, the temperature difference between the air combustion operation and the oxyfuel combustion operation is large, and the switching time between the air combustion operation and the oxyfuel combustion operation is also long.

  However, when the dehydrating device 11 is installed on the inlet side of the forced air fan 9 as in the first embodiment, the pressure loss balance between the carrier gas and the combustion gas on the downstream side of the forced air fan 9 becomes air combustion. No change during operation and oxyfuel combustion. This eliminates the need to increase the capacity of the forced air blower 9 and allows the exhaust gas to be recirculated during the oxyfuel combustion operation to flow only in the combustion gas flow system, so that the flow is equivalent to that of the dehydrator 11. It is not necessary to provide an additional device such as a damper 15 (see a virtual line in FIG. 7) for imparting resistance in the combustion gas distribution system. As a result, the operation of the oxyfuel boiler facility is not restricted.

  Further, a gas gas heater 12 as a heater for heating the exhaust gas on the outlet side of the dehydrating device 11 by the exhaust gas on the inlet side of the dehydrating device 11 is installed in the exhaust gas recirculation line 8R on the inlet side of the forced draft fan 9. As a result, heat loss can be minimized, and at the same time, the dehydrator 11 can be made compact and the dryness of the gas flowing into the forced air blower 9 can be secured. In addition, when the dehydrator 11 and the gas gas heater 12 are not installed on the inlet side of the forced air fan 9, the inlet gas temperature of the forced air fan 9 during the oxyfuel combustion operation is about 130 to 150 ° C. Since the temperature decreases to about 70 to 90 ° C. due to the installation of the apparatus 11 and the gas gas heater 12, it approaches the inlet gas (air) temperature (ie, atmospheric temperature = about 30 ° C.) of the forced air blower 9 during the air combustion operation. . Thereby, regarding the inlet gas temperature of the forced air blower 9, the temperature difference between the air combustion operation and the oxyfuel combustion operation is reduced, and the switching time between the air combustion operation and the oxyfuel combustion operation can be shortened.

  In this way, it is possible to prevent an increase in capacity of the forced air blower 9 and eliminate the need for an additional device for imparting distribution resistance.

  FIG. 3 shows a modification of the first embodiment of the oxyfuel boiler equipment of the present invention. In the figure, the same reference numerals as those in FIGS. Is the same as the first embodiment shown in FIGS. As shown in FIG. 3, this modification is characterized in that it is on the inlet side of the forced air blower 9 and the gas gas heater 12 so as to compensate for the pressure loss of the exhaust gas by the dehydrator 11 and the gas gas heater 12 as a heater. The auxiliary ventilator 9 ′ is provided on the exit side of the.

  When the auxiliary ventilator 9 ′ is provided as in the modification shown in FIG. 3, it becomes possible to compensate for the pressure loss of the exhaust gas caused by the dehydrator 11 and the gas gas heater 12 as a heater, and the forced ventilator 9 and the induction ventilator. 7 can be given a further capacity in terms of capacity, which is preferable.

  4 and 5 show a second embodiment of the oxyfuel boiler equipment according to the present invention. In the figure, the same reference numerals as those in FIGS. Is the same as the first embodiment shown in FIGS.

  In the second embodiment, as shown in FIGS. 4 and 5, the exhaust gas is branched from the inlet side of the forced draft fan 9 in the exhaust gas recirculation line 8R (downstream from the branch point of the extraction line 8D). A branch exhaust gas recirculation line 8R ′ that leads the section to the preheater 3 is provided, and the branch exhaust gas recirculation line 8R ′ is provided with a primary ventilator 13 that is arranged in parallel with the forced air blower 9. In the branch exhaust gas recirculation line 8R ′, the recirculation is performed on the inlet side of the primary ventilator 13, that is, at least upstream of the forced ventilator 9 and upstream of the air intake 14 (see FIG. 5) during air combustion operation. A dehydrator 11 for removing moisture from the exhaust gas to be discharged is provided, and a gas gas heater 12 as a heater for heating the exhaust gas on the outlet side of the dehydrator 11 by the exhaust gas on the inlet side of the dehydrator 11 is provided.

FIG. 4 shows the state during the oxyfuel combustion operation, but FIG. 5 shows the state during the air combustion operation. In the case of the air combustion operation shown in FIG. 5, the oxygen production device 10, the dehydration device 11, and the gas gas heater 12 are not used as shown by the phantom line, and air is taken in from the air intake 14 and the forced air blower 9. And the exhaust gas discharged from the boiler 1 is sent from the exhaust gas line 8 on the outlet side of the induction fan 7 to the chimney instead of the CO ₂ concentrating unit via the extraction line 8D. It has come to be.

  Next, the operation of the second embodiment will be described.

At the time of the oxyfuel combustion operation of the oxyfuel boiler equipment, the exhaust gas that has passed through the preheater 4 is cooled by the exhaust gas cooler 5, dust is collected by the dust removing device 6, and the pressure is increased by the induction blower 7, and then shown in FIG. As shown in the figure, the operation of the forced air blower 9 causes the exhaust gas recirculation line 8 </ b> R to recirculate the combustion gas for the boiler 1. After the combustion gas is preheated by the preheater 4, oxygen is supplied from the oxygen production apparatus 10 and introduced into the boiler 1. Part of the exhaust gas pressurized by the induction fan 7 is guided to the branch exhaust gas recirculation line 8R ′, and moisture is removed by the dehydrator 11. The exhaust gas from which moisture has been removed by the dehydrator 11 is heated by the exhaust gas on the inlet side of the dehydrator 11 when passing through the gas gas heater 12, and is then guided to the primary ventilator 13. By operation, the gas is recirculated from the branch exhaust gas recirculation line 8R ′ via the preheater 3 as a conveying gas for the pulverized coal of the mill 2. A part of the exhaust gas discharged from the boiler 1 is sent from the exhaust gas line 8 on the outlet side of the induction fan 7 to the CO ₂ concentration unit via the extraction line 8D, and the operation of separating and recovering CO ₂ from the exhaust gas is performed. Done.

On the other hand, during the air combustion operation of the oxyfuel boiler facility, as shown in FIG. 5, the dehydrator 11 and the gas gas heater 12 are not used, and air is introduced from the inlet side of the push-in ventilator 9 and the primary ventilator 13. The air is used as a combustion gas for the boiler 1 and a conveying gas for pulverized coal. The air used as the combustion gas is preheated by the preheater 4 and then introduced into the boiler 1 as it is without being supplied with oxygen from the oxygen production apparatus 10. The exhaust gas discharged from the boiler 1 is sent from the exhaust gas line 8 on the outlet side of the induction fan 7 through the extraction line 8D to the chimney instead of the CO ₂ concentration unit, and is released into the atmosphere.

  As in the second embodiment, the dehydrating apparatus is provided with a branch exhaust gas recirculation line 8R ′ that recirculates the exhaust gas as the transfer gas by the operation of a primary ventilator 13 provided in parallel with the forced draft fan 9. 11 is provided in the branch exhaust gas recirculation line 8R 'on the inlet side of the primary ventilator 13, the primary ventilator 13 is solely responsible for the transfer of the carrier gas, and the pusher ventilator 9 is solely the pressure of the combustion gas. It will be a form that bears. For this reason, the pressure loss balance between the carrier gas and the combustion gas does not change between the air combustion operation and the oxyfuel combustion operation on the downstream side of the forced air blower 9. This eliminates the need to increase the capacity of the forced air blower 9 and allows the exhaust gas to be recirculated during the oxyfuel combustion operation to flow only in the combustion gas flow system, so that the flow is equivalent to that of the dehydrator 11. It is not necessary to provide an additional device such as a damper 15 (see a virtual line in FIG. 7) for imparting resistance in the combustion gas distribution system. As a result, the operation of the oxyfuel boiler facility is not restricted.

  Furthermore, a gas gas heater 12 as a heater for heating the exhaust gas on the outlet side of the dehydrating device 11 by the exhaust gas on the input side of the dehydrating device 11 is connected to the branched exhaust gas recirculation line 8R ′ on the inlet side of the primary ventilator 13. By installing, heat loss can be minimized, and at the same time, the dehydrator 11 can be made compact and the dryness of the gas flowing into the primary ventilator 13 can be ensured.

  Thus, in the second embodiment of the oxyfuel boiler facility provided with the primary ventilator 13 provided in parallel with the forced draft fan 9, as in the first embodiment, the increase in the capacity of the forced draft fan 9 is prevented. Further, an additional device for imparting distribution resistance may be unnecessary.

  FIG. 6 is a modified example of the second embodiment of the oxyfuel boiler equipment of the present invention. In the figure, the same reference numerals as those in FIGS. Is the same as the second embodiment shown in FIGS. As shown in FIG. 6, the feature of this modification is that the oxygen from the oxygen production apparatus 10 is introduced into the inlet side of the forced air blower 9 with respect to the recirculated exhaust gas (the branch point of the extraction line 8D). It is the point which comprised so that it might mix in a more downstream side.

  When the oxygen from the oxygen production apparatus 10 is mixed with the recirculated exhaust gas on the inlet side of the forced air fan 9 as in the modification shown in FIG. 6, the oxygen and the exhaust gas are forced into the forced air fan. Therefore, even if a special mixer or the like is not installed, mixing of the oxygen and the exhaust gas is promoted and a uniform gas distribution is obtained.

  The oxygen and exhaust gas mixed by the forced air blower 9 are preheated by the preheater 4 and heated. This means that the temperature of the recirculated exhaust gas does not decrease until reaching the boiler 1 as compared with injecting room temperature oxygen into the exhaust gas preheated by the preheater 4. That is, since the mixed gas of oxygen and exhaust gas preheated by the preheater 4 is supplied to the boiler 1 at the same temperature, an improvement in combustibility can be expected.

  In addition, the mixing of oxygen into the inlet side of the forced air blower 9 improves the flow rate balance between the high temperature side (exhaust gas side) and the low temperature side (exhaust gas side to be recirculated) of the preheater 4. The gas side temperature efficiency is increased, the outlet gas temperature of the preheater 4 is lowered, and the exhaust gas cooler 5 installed on the downstream side can be reduced.

  Furthermore, since the temperature difference between the air combustion operation and the oxyfuel combustion operation becomes small with respect to the inlet gas temperature of the forced air blower 9 due to the mixing of oxygen into the inlet side of the forced air blower 9, Switching time for oxyfuel combustion operation can also be shortened.

  The oxyfuel boiler equipment of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Boiler 2 Mill 3 Preheater 4 Preheater 8R Exhaust gas recirculation line 8R 'Branch exhaust gas recirculation line 9 Pushing ventilator 9' Auxiliary ventilator 10 Oxygen production apparatus 11 Dehydration apparatus 12 Gas gas heater (heater)
13 Primary ventilator 14 Air intake

Claims (6)

An oxyfuel boiler facility in which a forced draft fan is provided in an exhaust gas recirculation line for recirculating exhaust gas discharged from a boiler as fuel transfer gas and combustion gas,
An oxyfuel boiler facility in which a dehydrator is provided at least upstream of the forced air blower and upstream of the air intake during air combustion operation. The dehydrator is provided in the exhaust gas recirculation line on the entry side of the forced air fan,
The oxyfuel boiler equipment according to claim 1, wherein a heater for heating the exhaust gas on the outlet side of the dehydrator by the exhaust gas on the inlet side of the dehydrator is provided in the exhaust gas recirculation line on the inlet side of the forced draft fan.   The oxyfuel boiler equipment according to claim 2, further comprising an auxiliary ventilator provided on an inlet side of the forced air ventilator so as to compensate for pressure loss of exhaust gas caused by the dehydrator and the heater. A branch exhaust gas recirculation line that recirculates the exhaust gas as the transfer gas by the operation of a primary ventilator provided in parallel with the forced draft fan;
The oxyfuel boiler equipment according to claim 1, wherein the dehydrator is provided in a branch exhaust gas recirculation line on an inlet side of the primary ventilator.   The oxyfuel boiler equipment according to claim 4, wherein a heater for heating the exhaust gas on the outlet side of the dehydrator by the exhaust gas on the inlet side of the dehydrator is provided in the branch exhaust gas recirculation line on the inlet side of the primary ventilator.   An oxygen production device is provided for supplying oxygen to the combustion gas recirculated by the exhaust gas recirculation line, and oxygen from the oxygen production device is mixed with the recirculated exhaust gas at the inlet side of the forced air blower. The oxyfuel boiler equipment according to claim 5 configured as described above.

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