JP3927916B2 - High temperature corrosion reduction device for circulating fluidized bed boiler - Google Patents

Description

【００５９】
表１の結果から、Ｃｌ、Ｓ、Ｆのような腐食成分は、５３μｍ以下の粒子径の成分比が大きいことがわかる。
【００６０】
実施例２
本発明装置を用いて廃棄物燃焼における過熱器の腐食速度を調べた。また比較のために図５に示す装置を用いて同様の腐食速度を調べた。
【００６１】
その結果を図３に示す。図３は横軸が燃料中の塩素濃度であり、縦軸は過熱器管（材質：ＳＵＳ３１０Ｓ）の最大腐食深さ（ｍｍ／年）を示している。
【００６２】
図３から明らかなように、燃料中の塩素濃度１％程度においても、過熱器管の腐食速度は０．５ｍｍ／年以下に低減されていることがわかる。
【００６３】
これは本発明の装置では外部熱交換器内の塩素濃度が従来装置に比べ小さい値に保持されているからである。このことを更に確認するために、燃料中の塩素濃度と外部熱交換器内の塩素濃度の関係を調べたところ、図４のような結果が得られた。
【００６４】
実施例３
図１に示す装置において、燃料として、建築廃材チップ、下水汚泥、農林廃棄物、食品廃棄物、ＲＤＦ等の再生可能エネルギー及びＲＰＦ、廃タイヤ等の産業廃棄物を混合した廃棄物（塩素濃度：１％含有）燃料を用いて、ボイラ管の腐食実験を行った。
【００６５】
その結果、蒸気圧力：１３０Ｋｇ／ｃｍ^２Ｇ、蒸気温度：５５０℃、発電端効率：３８％クラスの高効率発電が可能である事を確認した。
【００６６】
また過熱器腐食速度は０．５ｍｍ／年以下であり、排ガス中の公害成分を測定したところ、以下のような結果が得られた。
【００６７】
ＮＯ_ｘ＜１００ｐｐｍ（Ｏ_２＝６％）
ＳＯ_２＜１００ｐｐｍ（Ｏ_２＝６％）
ＣＯ ＜５０ｐｐｍ（Ｏ_２＝６％）
ＤＸＮ類０．１ｎｇ／Ｎｍ^３以下
【００６８】
【発明の効果】
本発明によると、外部熱交換器での高温腐食の問題を解消でき、発電の高効率化を実現できる循環流動層ボイラの高温腐食低減装置を提供できる。
【図面の簡単な説明】
【図１】本発明に係る循環流動層ボイラの高温腐食低減装置の一例を示す説明図
【図２】複数の流動層の配置例を示す平面図
【図３】過熱器の腐食速度を調べた結果を示すグラフ
【図４】燃料中の塩素濃度と外部熱交換器内の塩素濃度の関係を調べた結果を示すグラフ
【図５】従来の循環流動層ボイラの概略説明図
【符号の説明】
１：火炉
１００：デンスベッド部
１０１：火炉本体
１０２：燃焼ガスダクト
２：粒子捕集装置（サイクロン）
３：第１流動層
４：第２流動層
５：第３流動層
６：第４流動層
３００、４００、５００：仕切壁
３０１：粒子導入口
３０２：空気導入口
４０１：空気導入口
４０２：開口部
４０３：開口部
４０４：循環ライン
５０１：外部熱交換器
５０２：空気導入口
５０３：上部開口部
５０４：下部開口部
６００：開口部
６０１：空気導入口
６０２：側壁
６０３：粒子排出口
６０４：空気出口管
６０５：循環ライン
７：対流伝熱部
７００：燃焼排ガスダクト
８：バグフィルター[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-temperature corrosion reduction device for a circulating fluidized bed boiler having a wide range of fuel compatibility from gas to liquid to solid. Specifically, the problem of high-temperature corrosion in an external heat exchanger can be solved, and high efficiency of power generation can be realized. The present invention relates to a high temperature corrosion reduction device for a circulating fluidized bed boiler.
[0002]
[Prior art]
Waste power generation contributes greatly as a stable source of renewable energy to replace conventional fossil fuels, as a measure to prevent global warming, and as a measure to reduce the amount of landfill that leads to the extension of the life of final disposal sites. It is expected to contribute to the improvement of global energy problems, global environmental problems, and community problems.
[0003]
As a target for introducing waste power generation in FY2010 submitted in June 2001, a target of 4.17 million KW, which is 30% of all new energy, has been set. Since the actual result in 1999 is about 900,000 KW, it is said that it is necessary to increase the installed capacity five times.
[0004]
In addition, the legal system for building a recycling-oriented society has been steadily developed and reviewed, and since April 2003, the Special Measures Law (RPS system) concerning the use of new energy, etc. will be fully enforced. It is expected that new energy power generation will be promoted for waste such as garbage, sewage sludge, food waste, agriculture / forestry / fishery waste, papermaking black liquor, and building waste.
[0005]
In the promotion of new energy power generation, in recent years, circulating fluidized bed boilers that enable ultra-high efficiency power generation from waste combustion, which is the core of the waste power generation field, have attracted attention.
[0006]
[Problems to be solved by the invention]
As shown in FIG. 5, a conventional circulating fluidized bed boiler includes a furnace 50 having a fluidized bed, a particle collecting device 51, an external heat exchanger 52, a circulation system 53, a convection heat transfer section 54, a combustion exhaust gas duct. 55 and a bug filter 56 are provided.
[0007]
When combustion starts in a state where fuel such as waste, auxiliary fuel, dense bed materials such as gravel and sand, and circulating solids supplied to the bottom of the furnace 50 are fluidized by combustion air, high-temperature combustion gas is generated. The generated combustion gas is accompanied by some particles of the dense bed material and is sent to the particle collecting device 51 to collect the particles.
[0008]
The particles collected by the particle collecting device 51 are discharged downward and sent to the external heat exchanger 52 for heat recovery. The particles that have passed through the external heat exchanger 52 become a cold solid and are sent as a circulating solid to the dense bed portion at the bottom of the furnace through the circulation system 53 for circulation. The separated gas and ash separated from the particle collecting device 51 are sent to the convection heat transfer section 54, and heat is recovered from the gas. Thereafter, the ash is sent to the bag filter 56 through the flue gas duct 55 and separated and collected. In such an apparatus, high-temperature and high-pressure steam is generated using heat recovered by the external heat exchanger 52 and the convection heat transfer section 54.
[0009]
However, the waste that is the fuel source contains corrosive components such as chlorine and alkali metals. When these concentrations increase, the corrosive components flow into the external heat exchanger, There is a problem that the high temperature corrosion of the steel also increases to a level that cannot be ignored.
[0010]
Then, this invention makes it a subject to provide the high temperature corrosion reduction apparatus of the circulating fluidized bed boiler which can eliminate the problem of the high temperature corrosion in an external heat exchanger, and can implement | achieve the highly efficient electric power generation.
[0011]
[Means for Solving the Problems]
As a result of intensive studies to solve the above problems, the present inventor has found that a large amount of corrosive components are present on the fine particle side, leading to the present invention.
[0012]
That is, the said subject is solved by each following invention.
[0017]
(Claim 1 ) A furnace having a fluidized bed and particles discharged from the furnace accompanied by combustion gas are introduced, collected, discharged from below, and separated gas and ash discharged from above. A particle collection device, and a circulation system for circulating particles collected and discharged by the particle collection device to the furnace via an external heat exchanger, and a separation gas discharged from the particle collection device; In a circulating fluidized bed boiler comprising a convection heat transfer section that introduces ash and recovers heat from the gas, and a bag filter that separates and collects ash sent from the convection heat transfer section through a combustion exhaust gas duct,
The circulation system includes a first fluidized bed, a second fluidized bed, a third fluidized bed, and a fourth fluidized bed composed of spaces partitioned by a common partition wall;
The first fluidized bed is provided with a particle introduction port for introducing particles sent from the lower part of the particle collecting device at an upper portion of the space, and an air introduction port for introducing fluidized air at a lower portion, from the air introduction port. The supplied air has a structure that flows into the particle collecting device through the particle inlet,
The second fluidized bed has an air inlet for introducing fluidized air into the lower part of the space, and has an opening for discharging both particles and fluidized air at the upper part, and the first fluidized bed and the second fluidized bed An opening through which the particles of the first fluidized bed flow into the second fluidized bed at the bottom of the partition wall of the layer;
The third fluidized bed includes the external heat exchanger at a lower portion in the space, an air inlet for introducing fluidized air to the lower portion of the space, and a partition between the second fluidized bed and the third fluidized bed. Upper and lower openings are respectively provided at the upper and lower portions of the wall, and fluidized air introduced from the air inlet flows into the second fluidized bed through the upper opening, and the second fluidized bed The lower particles flow into the third fluidized bed from the lower opening,
The fourth fluidized bed has a structure having an opening at a lower portion of a partition wall with the third fluidized bed, and particles of the third fluidized bed flow into the fourth fluidized bed through the opening, An air inlet for introducing fluidized air into the lower part of the four fluidized bed space, a particle outlet at the lower part of the side wall of the fourth fluidized bed, an air outlet pipe at the upper part of the fourth fluidized bed, The high temperature corrosion reduction device for a circulating fluidized bed boiler, characterized in that an outlet pipe is connected to the combustion exhaust gas duct extending from the convection heat transfer section to a bag filter.
[0018]
(Claim 2) wherein the opening provided in the upper portion of the second fluidized bed, circulating fluidized bed temperature corrosion reduction apparatus of a boiler according to claim 1, characterized in that it is connected to the furnace.
[0019]
( 3 ) The high temperature corrosion of the circulating fluidized bed boiler according to ( 1 ) or (2 ), wherein the external heat exchanger of the third fluidized bed has a structure in which a superheater tube or an evaporator tube of a boiler is immersed. Reduction device.
[0020]
( 4 ) The high temperature corrosion reduction apparatus for a circulating fluidized bed boiler according to ( 1 ), ( 2 ) or ( 3 ), wherein the particle outlet of the fourth fluidized bed is connected to a furnace through a circulation line. .
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0022]
FIG. 1 is an explanatory view showing an example of a high-temperature corrosion reduction device for a circulating fluidized bed boiler according to the present invention, and FIG. 2 is a plan view showing an arrangement example of a plurality of fluidized beds.
[0023]
In the figure, reference numeral 1 denotes a furnace having a fluidized bed (dense bed). In the present invention, the structure of the furnace 1 is not particularly limited, but preferably, a dense bed portion 100 having a high superficial velocity is formed at the bottom of the furnace 1 and a furnace main body 101 having a low superficial velocity is formed at the top. Is preferably formed.
[0024]
The dense bed unit 100 is configured to be able to supply waste, auxiliary fuel, combustion air, circulating solid, dense bed material, and the like as a fuel source. When the combustion air is supplied, the dense bed unit 100 Is vigorously fluidized and mixed and stirred.
[0025]
Wastes include building waste chips, sewage sludge, agricultural and forestry waste, food waste, renewable energy such as RDF (Rufuse Derived Fuel), and industrial waste such as RPF (Rufuse Paper & Plastic Fuel) and waste tires. Can be mentioned.
[0026]
As the auxiliary fuel, liquid fuels such as heavy oil and light oil, gaseous fuels such as city gas and propane gas, and solid fuels such as coal may be used, and these auxiliary fuels may use the above-mentioned one type. Two or more kinds can be used in combination. It is also preferable to prepare liquid fuel, gaseous fuel, and solid fuel, respectively, so that they can be switched.
[0027]
Combustion air is preferably preheated in order to increase the combustion rate.
[0028]
The dense bed material, gravel or sand, can be used as the ceramic particles, mainly responsible for the heat held when being burned in a fluidized state.
[0029]
Circulating solids are particles that are partly recovered from the dense bed material after being discharged from the furnace 1 to the outside and then returned to the furnace 1 again.
[0030]
In the dense bed part 100, when the waste, auxiliary fuel, dense bed material, circulating solid, etc. are ignited in a state of being fluidized by the combustion air, they are violently burned and burned at a high temperature, and 900 ° C. in the furnace 1 Generates a certain amount of combustion gas.
[0031]
A part of the dense bed material forming a fluidized bed (dense bed) accompanies the combustion gas as a circulating solid (particle) and is led to the particle collecting device 2 through the combustion gas duct 102.
[0032]
In the particle collecting device 2, the particles discharged accompanying the combustion gas are separated. For example, a cyclone capable of collecting particles can be used as the particle collecting device 2.
[0033]
Hereinafter, the particle collecting device 2 is referred to as a cyclone 2.
[0034]
In the present invention, the first fluidized bed 3, the second fluidized bed 4, the third fluidized bed 5 and the first fluidized bed 3, which are unique to the present invention, are returned to the dense bed 100 through the circulation system. Four fluidized beds 6 are provided.
[0036]
The first fluidized bed 3, the second fluidized bed 4, the third fluidized bed 5, and the fourth fluidized bed 6 are basically formed by spaces partitioned by partition walls 300, 400, and 500 that are common to each other.
[0037]
The first fluidized bed 3 is provided with a particle inlet 301 for introducing particles sent from the lower part of the cyclone 2 in the upper part of the space, and an air inlet 302 for introducing fluidized air in the lower part.
[0038]
The air supplied from the air inlet 302 into the first fluidized bed 3 flows through the particle inlet 301 and flows into the cyclone. With this structure, air blow-up from the lower part of the cyclone 2 is enabled, and as a result, the particle collection performance in the cyclone 2 can be controlled. The particle collection performance can be controlled by adjusting the amount of air introduced from the air inlet 302. According to such air blow-up, fine particles (particles having a small particle size and specific gravity) in the particles rise to the cyclone 2 and are transported to the convection heat transfer section. The cause of the high temperature corrosion in the external heat exchanger is greatly influenced by the fine particles, so that if the fine particles can be discharged in front of the external heat exchanger, the cause of the high temperature corrosion can be eliminated.
[0039]
The fluidizing gas flow rate of the first fluidized bed 3 is preferably set to be relatively large in order to blow up the fine particles among the particles collected by the cyclone 2, specifically 0.3 to 0. The range is 6 m / s. Moreover, the temperature in the 1st fluidized bed 3 is the range of 850-900 degreeC same as furnace temperature. Therefore, the temperature of the gas blown up to the cyclone 2 is in the range of about 850 to 900 ° C.
[0040]
The second fluidized bed 4 includes an air inlet 401 for introducing fluidized air to the lower part of the space, and an opening 402 for discharging both particles and fluidized air to the furnace at the upper part. An opening 403 through which the particles of the first fluidized bed 3 flow into the second fluidized bed 4 is provided below the partition wall 300 of the first fluidized bed 3 and the second fluidized bed 4.
[0041]
In this embodiment, since the opening 403 is formed in the lower part of the partition wall 300, the particles sent from the first fluidized bed 3 to the second fluidized bed 4 are fine particles that could not be removed by the first fluidized bed 3. These particles are discharged from the opening 402 by the fluidized air supplied from the air inlet 401. Since the fine particles, which are corrosion components that could not be removed by the first fluidized bed 3, are purged (removed) by the second fluidized bed 4, countermeasures against high temperature corrosion of the external heat exchanger are further possible. The opening 402 is connected to the dense bed 100 of the furnace 1 via a circulation line 404. For this reason, circulating solids (particles) that are corrosive components are sent to the furnace 1.
[0042]
The fluidizing gas flow rate of the second fluidized bed 4 is preferably set in the range of 0.2 to 0.4 m / s in order to form a normal developed fluidized bed.
[0043]
The temperature in the 2nd fluidized bed 4 is the range of 850-900 degreeC same as a furnace.
[0044]
The third fluidized bed 5 includes an external heat exchanger 501 at the lower part of the space, and an air inlet 502 for introducing fluidized air to the lower part of the space. An upper opening 503 and a lower opening 504 are respectively provided at the upper and lower portions of the partition wall 400 of the second fluidized bed 4 and the third fluidized bed 5.
[0045]
Due to such a structure, the fluidized air introduced from the air introduction port 502 flows into the second fluidized bed 4 through the upper opening 503. Using this air flow, the second fluidized bed 4 is purged and removed by the fine particles that are corrosive components in the third fluidized bed 5.
[0046]
In the third fluidized bed 5, the gas temperature is lowered to about 550 to 650 ° C. by the heat exchanger 501, so that the particles are not in a molten state and the viscosity is lowered. For this reason, fine particles which are corrosive components and relatively large particles having a high specific gravity are easily separated. This action can be effectively used in the present invention.
[0047]
In the structure of this aspect, relatively large particles in the second fluidized bed 4 flow into the third fluidized bed 5 from the lower opening 504.
[0048]
Although this external heat exchanger 501 is not specifically limited, For example, it is preferable that it is the structure which immersed the superheater pipe | tube and evaporation pipe | tube of the boiler. In the present invention, high-temperature corrosion of these superheater tubes and evaporator tubes can be reduced.
[0049]
The fluidizing gas flow rate of the third fluidized bed 5 is preferably set to a relatively slow flow rate in order to prevent wear of the submerged heat transfer tubes. Specifically, the fluidizing gas flow rate is 0.2 m / It is preferably set to about s.
[0050]
The fourth fluidized bed 6 includes an opening 600 at the lower part of the partition wall 500 with the third fluidized bed 5. Further, the particles of the third fluidized bed 5 flow into the fourth fluidized bed 6 through the opening 600. An air inlet 601 for introducing fluidized air is provided in the lower part of the fourth fluidized bed 6 space.
[0051]
A particle discharge port 603 is provided in the lower part of the side wall 602 of the fourth fluidized bed 6. An air outlet pipe 604 is provided above the fourth fluidized bed 6, and the air outlet pipe 604 is connected to a combustion exhaust gas duct 700 extending from the convection heat transfer section 7 to the bag filter 8.
[0052]
The flow rate of the fluidized gas in the fourth fluidized bed 6 is preferably set high in order to increase the separation efficiency, and specifically, it is set in the range of 0.3 to 0.6 m / s.
[0053]
Moreover, since the gas temperature in the 4th fluidized bed 6 is comparatively low with about 500-600 degreeC, there exists little particle viscosity and it exists in the state which is easy to isolate | separate. For this reason, when fluidized air is supplied, fine particles that were not separated in the previous process and relatively large fine particles are easily separated, and the large particles are circulated to the furnace 1 from the particle discharge port 603 via the circulation line 605. Is sent and used as a circulation. On the other hand, the fine particles discharged from the air outlet pipe 604 are sent to the bag filter 8 through the combustion exhaust gas duct 700 and removed.
[0054]
The separated gas and ash discharged from the cyclone 2 are introduced into the convection heat transfer section 7. In the convection heat transfer section 7, heat is recovered from the separated gas by a heat exchanger. The separated gas and ash are recovered from the heat and then sent from the convection heat transfer section 7 to the bag filter 8 through the combustion exhaust gas duct 700 to remove the ash. The separated gas is discharged out of the system from the bag filter 8 and, for example, exhaust gas treatment is performed.
[0056]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by this Example.
[0057]
Example 1
When the relationship between the corrosive component and the particle size was examined by a combustion test using RPF as the fuel, the results shown in Table 1 were obtained. In Table 1, EHE is an abbreviation for external heat exchanger.
[0058]
[Table 1]

[0059]
From the results of Table 1, it can be seen that corrosion components such as Cl, S, and F have a large component ratio of particle diameters of 53 μm or less.
[0060]
Example 2
The corrosion rate of the superheater in waste combustion was investigated using the apparatus of the present invention. For comparison, the same corrosion rate was examined using the apparatus shown in FIG.
[0061]
The result is shown in FIG. In FIG. 3, the horizontal axis represents the chlorine concentration in the fuel, and the vertical axis represents the maximum corrosion depth (mm / year) of the superheater tube (material: SUS310S).
[0062]
As can be seen from FIG. 3, the corrosion rate of the superheater tube is reduced to 0.5 mm / year or less even at a chlorine concentration of about 1% in the fuel.
[0063]
This is because in the apparatus of the present invention, the chlorine concentration in the external heat exchanger is maintained at a smaller value than in the conventional apparatus. In order to further confirm this, when the relationship between the chlorine concentration in the fuel and the chlorine concentration in the external heat exchanger was examined, the results shown in FIG. 4 were obtained.
[0064]
Example 3
In the apparatus shown in FIG. 1, waste (mixture of chlorine: 1% containing) Fuel was used to conduct corrosion experiments on boiler tubes.
[0065]
As a result, it was confirmed that high-efficiency power generation with steam pressure: 130 Kg / cm ² G, steam temperature: 550 ° C., and power generation end efficiency: 38% class was possible.
[0066]
Moreover, the superheater corrosion rate was 0.5 mm / year or less, and when the pollutant component in the exhaust gas was measured, the following results were obtained.
[0067]
NO _x <100 ppm (O ₂ = 6%)
SO ₂ <100 ppm (O ₂ = 6%)
CO <50 ppm (O ₂ = 6%)
DXNs 0.1 ng / Nm ³ or less [0068]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the problem of the high temperature corrosion in an external heat exchanger can be eliminated, and the high temperature corrosion reduction apparatus of the circulating fluidized bed boiler which can implement | achieve efficiency improvement of electric power generation can be provided.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing an example of a high-temperature corrosion reducing apparatus for a circulating fluidized bed boiler according to the present invention. FIG. 2 is a plan view showing an arrangement example of a plurality of fluidized beds. Graph showing the results [Fig. 4] Graph showing the results of examining the relationship between the chlorine concentration in the fuel and the chlorine concentration in the external heat exchanger [Fig. 5] Schematic explanatory diagram of a conventional circulating fluidized bed boiler [Explanation of symbols]
1: furnace 100: dense bed 101: furnace body 102: combustion gas duct 2: particle collecting device (cyclone)
3: First fluidized bed 4: Second fluidized bed 5: Third fluidized bed 6: Fourth fluidized bed 300, 400, 500: Partition wall 301: Particle inlet 302: Air inlet 401: Air inlet 402: Opening Section 403: Opening 404: Circulation line 501: External heat exchanger 502: Air inlet 503: Upper opening 504: Lower opening 600: Opening 601: Air inlet 602: Side wall 603: Particle outlet 604: Air Outlet pipe 605: Circulation line 7: Convection heat transfer section 700: Combustion exhaust gas duct 8: Bag filter

Claims (4)

A furnace having a fluidized bed, and a particle collector for introducing particles discharged from the furnace accompanied by combustion gas, collecting the particles and discharging them from below, and discharging separated gas and ash from above A circulation system for circulating the particles collected and discharged by the particle collecting device to the furnace via an external heat exchanger, introducing separation gas and ash discharged from the particle collecting device, In a circulating fluidized bed boiler comprising a convection heat transfer section that recovers heat from gas, and a bag filter that separates and collects ash sent from the convection heat transfer section through a combustion exhaust gas duct,
The circulation system includes a first fluidized bed, a second fluidized bed, a third fluidized bed, and a fourth fluidized bed composed of spaces partitioned by a common partition wall;
The first fluidized bed is provided with a particle introduction port for introducing particles sent from the lower part of the particle collecting device at an upper portion of the space, and an air introduction port for introducing fluidized air at a lower portion, from the air introduction port. The supplied air has a structure that flows into the particle collecting device through the particle inlet,
The second fluidized bed has an air inlet for introducing fluidized air into the lower part of the space, and has an opening for discharging both particles and fluidized air at the upper part, and the first fluidized bed and the second fluidized bed An opening through which the particles of the first fluidized bed flow into the second fluidized bed at the bottom of the partition wall of the layer;
The third fluidized bed includes the external heat exchanger at a lower portion in the space, an air inlet for introducing fluidized air to the lower portion of the space, and a partition between the second fluidized bed and the third fluidized bed. Upper and lower openings are respectively provided at the upper and lower portions of the wall, and fluidized air introduced from the air inlet flows into the second fluidized bed through the upper opening, and the second fluidized bed The lower particles flow into the third fluidized bed from the lower opening,
The fourth fluidized bed has a structure having an opening at a lower portion of a partition wall with the third fluidized bed, and particles of the third fluidized bed flow into the fourth fluidized bed through the opening, An air inlet for introducing fluidized air into the lower part of the four fluidized bed space, a particle outlet at the lower part of the side wall of the fourth fluidized bed, an air outlet pipe at the upper part of the fourth fluidized bed, The high temperature corrosion reduction device for a circulating fluidized bed boiler, characterized in that an outlet pipe is connected to the combustion exhaust gas duct extending from the convection heat transfer section to a bag filter. The opening provided in the upper portion of the second fluidized bed, circulating fluidized bed temperature corrosion reduction apparatus of a boiler according to claim 1, characterized in that it is connected to the furnace. The high-temperature corrosion reduction apparatus for a circulating fluidized bed boiler according to claim 1 or 2, wherein the external heat exchanger of the third fluidized bed has a configuration in which a superheater tube or an evaporator tube of a boiler is immersed. The particle outlet of the fourth fluidized bed, high-temperature corrosion reducing device circulating fluidized bed boiler according to claim 1, 2 or 3 wherein that are connected to the furnace via a circulation line.

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