JP3495015B2 - Method for recovering heat from chlorine-containing combustibles and solidified fuel produced from chlorine-containing combustibles - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for burning chlorine-containing combustible material such as municipal waste in a fluidized bed boiler to recover heat, and a solidified fuel produced from the chlorine-containing combustible material suitable as a fuel for the fluidized bed boiler. It is about.

[0002]

2. Description of the Related Art As fuels for fluidized bed boilers, coal, various sludges, industrial wastes, municipal solid wastes, etc. are known, but various problems occur due to impurities contained in the fuels. When the impurities are chlorine, they are converted into hydrogen chloride by combustion, and the corrosion of the heat transfer tube of the boiler due to the generated hydrogen chloride poses a problem. It is well known that hydrogen chloride is a component that corrodes the heat transfer tubes of boilers. Further, the corrosion of the heat transfer tube of the boiler due to hydrogen chloride rapidly progresses as the surface temperature of the heat transfer tube rises as the recovered steam temperature increases. Therefore, in order to suppress the corrosion of the heat transfer tube, use a fuel with a low chlorine content, or
Alternatively, a method of limiting the steam temperature to a temperature at which corrosion of the heat transfer tube of the boiler does not easily occur is generally adopted. However, since it is possible to generate power with high efficiency by recovering steam at a higher temperature, it is desirable to have a higher steam temperature, and therefore it is necessary to use expensive heat transfer tube materials that are resistant to corrosion. There is.

As the combustible material containing chlorine, there is generally "urban waste". Municipal solid waste is known to be solidified into a fuel, and generally, it is a drying process, a crushing process, a sorting process for separating incombustible substances such as iron, aluminum, sand, and glass, and the addition of a Ca compound. It is solidified by the process and molding process, and is called RDF (dust solidified fuel). It is generally known that the purpose of adding a Ca compound during RDF production is to prevent odor of RDF, solidify RDF, and capture hydrogen chloride from combustion exhaust gas. In this case, the same object as above can be achieved by using a compound of Mg which is the same alkaline earth metal as Ca.

[0004] For example, in Japanese Patent Laid-Open No. 6-185722, CaO and Ca (O) are added as additives during RDF production.
It is described that a Ca compound such as H) ₂ or a mixture of Ca compound and fly ash is used. In these conventional techniques, there is no mention of the operational effects such as inhibition of corrosion of the heat transfer tube when the RDF is burned.
Further, for example, in JP-A-9-126434, in a fluidized bed boiler or the like that burns a chlorine-containing fuel, for the purpose of suppressing corrosion of a heat exchanger installed in a rear flue of a furnace outlet, CaO, Ca An apparatus for supplying Ca compounds such as (OH) ₂ and CaCO _{3 to} the rear flue of the furnace outlet is disclosed. However, the above-mentioned publication makes no mention of the inhibition of corrosion of the heat transfer tube provided in the fluidized bed, and moreover clearly states that the Ca compound is effective in inhibiting the corrosion.

Further, for example, Japanese Patent Laid-Open No. 2000-29791.
Japanese Patent Publication No. 5 discloses a technique of adding a Ca compound and a Mg compound as a measure for preventing ash from adhering to a furnace wall and a cyclone in a subsequent stage when a fuel containing chlorine is burned in a fluidized bed furnace or the like. . However, the technique disclosed in the above publication is
In order to suppress the formation of deposits on cyclones, etc., C
One or both of the a compound and the Mg compound are supplied onto the fluidized bed or the like, and there is no mention of corrosion inhibition of the heat transfer tube provided in the fluidized bed,
Moreover, it is stated that both the Ca compound and the Mg compound are effective in suppressing the adhesion.

[0006]

Also in the fluidized bed boiler, development of a technique capable of coping with various fuels is being advanced. Particularly, as a technique effective for a chlorine-containing fuel, for example, an internal circulation fluidized bed boiler, External circulating fluidized bed boilers are known. In the conventional technology so far, the steam temperature is 40
Although there was a limit to recovering steam at about 0 ° C, the development of the above-mentioned internal circulating fluidized bed boiler and external circulating fluidized bed boiler increased the steam conditions to a high temperature, resulting in poor chlorine-containing fuel. , For example, in a boiler fueled by municipal waste,
It becomes possible to adopt a steam temperature higher than 400 ° C., and highly efficient power generation is possible. However,
If the steam having a steam temperature of 400 ° C. or higher is to be recovered, it is necessary to select a high quality and expensive material for the heat transfer tube.

The present invention has been made in view of the above points, and an object of the present invention is to use a heat transfer tube of a fluidized bed boiler for recovering steam having a steam temperature of 400 ° C. or more, not a high-grade and expensive material, but a general material. It is possible to use heat transfer tubes made of various materials, while suppressing corrosion of the heat transfer tubes of the fluidized bed boiler, it is possible to recover steam of 400 ° C or higher and generate power with high efficiency from chlorine-containing combustible substances. (EN) A method of recovering solidified fuel and a solidified fuel produced from a chlorine-containing combustible material.

[0008]

In order to achieve the above object, a method of recovering heat from a chlorine-containing combustible material of the present invention is to use a chlorine-containing combustible material as a fuel in a fluidized bed of a fluidized bed boiler. In a method for recovering superheated steam with a superheater tube provided, a magnesium compound is added to the fluidized bed of a fluidized bed boiler to suppress the corrosion of the superheater tube,
It is configured to recover superheated steam at 0 ° C. or higher.
In this case, it is preferable to add the magnesium compound into the fluidized bed below the superheater tube.

Further, the method of the present invention is a method of recovering superheated steam by a superheater tube provided in a fluidized bed of a fluidized bed boiler using a chlorine-containing combustible material as a fuel, wherein the chlorine-containing combustible material contains MgO and Mg. The solidified fuel molded by adding a magnesium compound such as (OH) ₂ or MgCO ₃ is supplied to the fluidized bed boiler to suppress the corrosion of the superheater pipe while maintaining the temperature at 400 ° C. in the superheater pipe. It is characterized by recovering the above superheated steam.

In these methods, a circulating fluidized bed boiler can be used as the fluidized bed boiler. The amount of magnesium compound added is 20 to 100%, preferably 20 to 4 based on the ash content of the chlorine-containing combustible material in terms of MgO.
It is preferable that the added amount be 0%. As the magnesium compound, MgO, Mg (OH) ₂ , MgCO ₃ or the like can be used, but MgO is substantially superior and M
It is preferable to use gO.

Thus, in order to solve the above problems,
In the present invention, corrosion of the heat transfer tube is suppressed by supplying the Mg compound from the lower part of the fluidized bed provided with the heat transfer tube. Alternatively, when the chlorine-containing fuel is used as the fuel for the fluidized bed boiler, the Mg compound is added to the chlorine-containing fuel in advance to solidify the fuel and then burned in the circulating fluidized bed.

The solidified fuel produced from the chlorine-containing combustible material of the present invention is for recovering superheated steam of 400 ° C. or higher in the superheater tube while suppressing corrosion of the superheater tube provided in the fluidized bed. A solidified fuel used as a fuel for a fluidized-bed boiler, which is a chlorine-containing combustible material that has been dried, crushed, and separated from an incombustible material, and a magnesium compound such as MgO, Mg (OH) ₂ , or MgCO ₃ . It is characterized by being added and molded. In this case, the addition amount of the magnesium compound is Mg
If the amount of O converted is 2 to 10% of the solidified fuel and the ash content of the solidified fuel is 10%, the amount of MgO converted is 20 to 100% with respect to the ash of the chlorine-containing combustible material. . Magnesium compounds to be added are MgO, Mg (O
H) ₂ , MgCO _3, etc., but MgO is substantially superior. Municipal waste can be used as the chlorine-containing combustible material. When using municipal waste, the fuel of the present invention is RD
It is F.

As a method of burning a chlorine-containing fuel in a fluidized bed boiler, technical development of an internal circulating fluidized bed system or an external circulating fluidized bed system has been carried out. Here, the term "internal circulation fluidized bed boiler" means that the fluidized bed is divided into a combustion cell and a heat collecting cell by partition walls, and the superficial velocity of the heat collecting cell is made smaller than the superficial velocity of the combustion cell to make a fluidized material. (BM) is moved from the combustion cell to the heat collecting cell across the partition wall, heat is applied to the heat collecting cell transfer surface (heat transfer tube, etc.), and is returned to the combustion cell from the lower opening of the partition wall. A device that collects heat from the heat collecting cell. In addition, "external circulation fluidized bed boiler" means
Particles scattered with the combustion gas are collected by a cyclone,
It refers to a device that returns the collected particles to the fluidized bed to recover the heat of the particles.

With these technological developments, it has become possible to recover a steam temperature of a high temperature which has never been seen before, for example, a steam of 500.degree. However, even in this case, it is not possible to completely prevent corrosion of the heat transfer tubes and the like due to the chlorine content contained in the fuel. For this reason, it was necessary to select high-quality and expensive materials for the heat transfer tubes of the boiler.
Therefore, the above-described technique of the present invention was developed so that a heat transfer tube made of a general material rather than a high-grade and expensive material can be used.

It is known that the corrosion of the heat transfer tube of the boiler is caused by the low melting point compound attached to the surface thereof. Although the power generation efficiency of the plant increases as the steam temperature of the boiler rises, corrosion of the heat transfer tubes of the boiler increases as the steam temperature rises. In order to suppress this corrosion due to high temperature, it is necessary to develop a technique for suppressing the adhesion of low melting point compounds. As a result of investigating the effectiveness of addition of the Ca compound and the Mg compound in order to reduce the low-melting point compound adhering to the surface of the heat transfer tube, it was found that the presence of the Mg compound is effective. It was revealed that the presence of the Mg compound can significantly suppress the corrosion of the heat transfer tube. As a result, it has become possible to use heat transfer tubes made of cheaper materials.
Alternatively, it has become possible to use the heat transfer tube for a longer period of time without replacement.

Using the fluidized bed combustion boiler as shown in FIG. 1, the above-mentioned Ca compound and Mg compound addition tests were carried out. Wind boxes 12, 14, 16 below the body 10 of the fluidized bed
Combustion air is supplied from each to fluidize the fluid material. The fluidized bed is divided into three cells by partition walls 18 and 20 arranged as shown in FIG. 1, and a combustion cell 22 that supplies fuel for combustion and a circulation cell provided between the partition walls 18 and 20. 24, heat transfer tube (superheater tube) 2 in the fluidized bed
6 is installed in the heat collection cell 28. The RDF fuel is supplied from above the combustion cell 22 to
The RDF is burnt at. The fluid material in the combustion cell 22 moves to the heat collection cell 28 via the circulation cell 24 and is circulated from the lower part of the heat collection cell 28 to the circulation cell 24 and the combustion cell 22. Specifically, when the circulation cell 24 is fluidized at a superficial velocity higher than the superficial velocity of the heat collecting cell 28, the circulation cell 2
The fluid material of No. 4 is circulated in the upper part of the heat collecting cell 28, the fluid material entering the heat collecting cell 28 supplies heat to the heat transfer tube 26, and then the circulation cell 24 and the combustion cell 22 from the lower part of the heat collecting cell 28. Is circulated to. In this case, the temperature of the combustion cell 22 is 8
50 ° C., the temperature of the heat collecting cell 28 is 700 ° C., and the temperature of the steam recovered by the heat transfer pipe (superheater pipe) 26 is 400 ° C. to 500 ° C.
The temperature is controlled to reach a predetermined temperature of ° C.

In such an apparatus, a Ca compound or a Mg compound was added into the heat collecting cell by the following three methods to observe the corrosion state of the heat transfer tube. The Ca compound or the Mg compound is added by the method A: supply from the supply nozzle 30, the method B: supply from the supply nozzle 32, or
Method C: It was carried out by the method of adding it at the time of manufacturing RDF. As a result, Ca compounds (Ca (O
The addition of H) ₂ ) had no effect on the corrosion of the heat transfer tube by any method. Furthermore, when a Ca compound was added, the amount of ash attached to the heat transfer tube increased, and the effect of inhibiting heat transfer became clear. From these points, the Ca compound is not effective in suppressing the corrosion of the heat transfer tube, but rather adversely affects the heat transfer characteristics and the like, so it is a substance which should not be added. In addition, Mg compound (Mg
Even when O) was supplied from the supply nozzle 32 by the B method, no effect was observed in suppressing the corrosion of the heat transfer tube. It is considered that this is because the supplied finely divided Mg compound does not move to the heat collecting cell 28 but scatters into the empty column together with the combustion gas.

On the other hand, Mg compounds (M in this test)
In the method of directly supplying (gO) from the supply nozzle 30 to the heat collection cell 28 by the method A, the effect of suppressing corrosion of the heat transfer tube was clearly recognized. Further, as a method of adding the Mg compound, a method of adding it at the time of manufacturing the C method RDF was also found to have an effect of suppressing the corrosion of the heat transfer tube. That is, FIG.
As shown in, it was revealed that the RDF manufactured by adding the Mg compound (MgO) at the time of manufacturing the RDF is effective in suppressing corrosion. This is the addition of MgO in place of the Ca compound that was conventionally added during RDF production, eliminating Ca compounds that have an adverse effect such as an increase in the amount of ash and the adhesion of ash to the transmission surface, and a corrosion inhibition effect. With Mg
This is the effect of adding the compound.

The Mg compound (MgO) to be added is, for example, fine powder particles having a 100-mesh pass of 80%, and in the method of supplying heat from the supply nozzle 30 to the heat collecting cell 28, the number of supply nozzles increases as the apparatus becomes larger. Although there is a problem that it must be, it is sufficiently effective in suppressing corrosion. On the other hand, the RDF manufactured by adding the Mg compound (MgO) at the time of manufacturing the RDF has no problem even when it is put into a large-sized apparatus, and is effective in suppressing corrosion. In this case, if the addition amount of the Mg compound (MgO equivalent amount) is 2% or more of RDF, it has an effect of suppressing corrosion. The larger the amount added, the better. However, most of the added Mg compound scatters and is collected together with the RDF ash by a dust collector (not shown) in the subsequent stage. Will be done. Therefore, the addition amount of the Mg compound (MgO equivalent amount) is economical up to about 10% of RDF.
If the ash content of RDF is 10%, the
This corresponds to the added amount of 20 to 100% in terms of O.

Further, as in the conventional case, the RDF added with the Ca compound is put into the combustion cell 22 and burned, and the heat collection cell 2
Even when recovering vapor at 400 ° C. or higher by the heat transfer tube (superheater tube) 26 in 8, the amount of Mg compound added from the supply nozzle 30 to the fluidized bed of the heat collection cell 28 provided with the heat transfer tube (superheater tube) 26 By supplying a large amount, the effect of suppressing the corrosion of the heat transfer tube can be obtained.

It is known to add a Ca compound or a Mg compound at the time of producing RDF. The reason for adding these is, as described above, the prevention of odor of RDF, immobilization, and hydrogen chloride at the time of combustion. This is for removal.
As described above, in the conventional technique, the Ca compound or the Mg compound is added at the time of RDF production for the purpose of preventing odor of RDF, immobilizing it, and removing hydrogen chloride during combustion.
On the other hand, in the technique of the present invention, only the Mg compound is added when the RDF is manufactured in order to suppress the corrosion of the heat transfer tube of the boiler. The addition of the Ca compound to the present technique is not effective, but there are unfavorable problems such as an increase in the amount of ash and an increase in the adhesion of ash to the transmission surface.

As described above, the technique of adding only the Mg compound at the time of producing RDF is a novel technique whose purpose and action are completely different from those of the prior art, and the present invention is based on this novel technique. It was done. That is, in the present invention, when RDF fuel is burned in a fluidized bed combustion boiler and high-temperature steam is recovered, the RDF produced by adding only the Mg compound is burned, so that steam of 400 ° C. or higher is generated. Corrosion of the heat transfer tube to be recovered can be suppressed.
Of course, the corrosion of the heat transfer tube can be suppressed even if the steam temperature is lower than 400 ° C. Also, R
M instead of the Ca compound that was conventionally added during DF manufacturing
Since the g compound is added, the amount of ash becomes the same as in the conventional case, and, in addition to having all the effects of the conventional RDF, the effect of inhibiting corrosion can be obtained. It should be noted that the addition of the Mg compound during the production of RDF was also effective in suppressing the formation of deposits on the air nozzle (dispersion plate) provided in the lower portion of the combustion section and in suppressing corrosion.

Alternatively, as described above, when the RDF fuel is burned in the fluidized bed combustion boiler to recover the high temperature steam, only the Mg compound is added to the fluidized bed heat collecting cell having the heat transfer tube for recovering the high temperature steam. Then, a method of suppressing corrosion of the heat transfer tube may be adopted. At this time, the corrosion can be suppressed more effectively by supplying the Mg compound into the layer of the heat collecting cell having the heat transfer tube. If a heat transfer tube is supplied from above a layer of a heat collecting cell, most of it will be scattered along with the flowing gas, so the supplied Mg compound will not work effectively, and it will be necessary to supply a large amount. come.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the following embodiments, and can be appropriately modified and implemented. FIG. 2 shows an apparatus for carrying out the method for recovering heat from a chlorine-containing combustible material according to the first embodiment of the present invention. The present embodiment is intended to suppress corrosion of a heat transfer tube provided in a fluidized bed when RDF is produced from a chlorine-containing waste, for example, municipal solid waste, as a fuel for a fluidized bed boiler that recovers steam at 400 ° C or higher. As an example, the RDF is manufactured by adding only the Mg compound. That is, with a heat transfer tube provided in the fluidized bed, a circulating fluidized bed boiler that recovers vapor at 400 ° C. or higher, and M for chlorine-containing waste
The RDF molded by adding the g compound is supplied and burned.

For example, when solidifying municipal waste to produce RDF, the municipal waste is dried, crushed, iron,
After a Mg compound (for example, MgO) is added and mixed through a selection process for separating non-combustible materials such as aluminum, sand, and glass, it is molded. In FIG. 2, the devices that perform drying, crushing (crushing), and separation of incombustibles are collectively referred to as a solidification device 34, but in practice, as an example, a primary crusher, a drier, an aluminum sorter, and a magnetic sorter. , Wind power sorter,
It is composed of a secondary crusher. Also, the molding machine 36
The RDF discharged from the
It is stored and shipped as a DF.

As the circulating fluidized bed boiler, as an example,
A device having a configuration as shown in FIG. 2 is used. As already mentioned, the wind boxes 12, 14, 16 below the body 10 of the fluidized bed.
Combustion air is supplied from each to fluidize the fluid material. 38 is a dispersion plate provided with an air nozzle. The fluidized bed is divided into three cells by partition walls 18 and 20 arranged as shown in FIG. 2, a combustion cell 22 that supplies fuel for combustion, and a circulation cell provided between the partition walls 18 and 20. 24, a heat collection cell 28 having a heat transfer tube (superheater tube) 26 installed in the fluidized bed. The RDF manufactured by adding the Mg compound is supplied from the upper part of the combustion cell 22,
Combustion of the RDF is performed in the combustion cell 22. The fluid material in the combustion cell 22 moves to the heat collection cell 28 via the circulation cell 24 and is circulated from the lower part of the heat collection cell 28 to the circulation cell 24 and the combustion cell 22. Specifically, when the circulation cell 24 is fluidized at a superficial velocity that is higher than the superficial velocity of the heat collection cell 28, the fluid material of the circulation cell 24 is circulated to the upper part of the heat collection cell 28, The fluid substance that entered the heat transfer tube 26
After supplying heat to the circulation cell 2
4 and the combustion cell 22. In this case, the temperature of the combustion cell 22 is 850 ° C. and the temperature of the heat collecting cell 28 is 700.
℃, steam temperature recovered in the heat transfer tube (superheater tube) 26 is 4
The temperature is controlled to reach a predetermined temperature from 00 ° C to 500 ° C.

In the present embodiment, RDF formed by adding a Mg compound (for example, MgO) to chlorine-containing waste such as municipal waste is supplied from the upper portion of the combustion cell 22 and burned to collect heat. Even when recovering vapor at 400 ° C or higher with the heat transfer tube (superheater tube) 26 installed in the cell 28, M
Heat transfer tube (superheater tube) due to the effect of adding g compound 26
The corrosion of can be suppressed. In addition, since the Mg compound is added instead of the Ca compound that was conventionally added during the RDF production, the amount of ash is the same as that of the conventional one, and in addition to having all the effects of the conventional RDF, the effect of inhibiting corrosion is obtained. can get. In addition, in the present embodiment, an effect can be recognized for suppressing the generation of deposits on the air nozzle in the lower part of the fluidized bed and suppressing corrosion.

FIG. 1 shows an apparatus for carrying out a method for recovering heat from a chlorine-containing combustible material according to a second embodiment of the present invention. In the present embodiment, a heat transfer tube (superheater tube) provided in the fluidized bed is used in a circulating fluidized bed boiler that recovers steam at 400 ° C. or higher, from the bottom of the fluidized bed of the heat collection cell provided with the superheater tube. , Mg compounds are supplied to suppress corrosion of the superheater tube. The structure of the circulating fluidized bed boiler is the same as that of the first embodiment. In the present embodiment, a Mg compound (for example, MgO) is added into the fluidized bed below the heat transfer tube (superheater tube) 26 by the supply nozzle 30 provided at the bottom of the heat collection cell 28. (Superheater tube) 2
Even in the case of recovering steam at 400 ° C. or higher in 6, it is possible to suppress corrosion of the heat transfer tube (superheater tube) 26.

[0029]

Since the present invention is configured as described above, it has the following effects. (1) Corrosion of the heat transfer tube (superheater tube) provided in the fluidized bed increases when the steam temperature to be recovered rises to 400 ° C. or higher, but MgO, Mg (OH) ₂ , MgCO is added as a fuel to chlorine-containing combustibles. Mg such as ₃
A heat transfer tube (superheater tube) that recovers vapor at 400 ° C or higher by using a solidified fuel (RDF) molded by adding a compound or adding a Mg compound in a fluidized bed in which a heat transfer tube is installed. ) Can be suppressed. (2) Since the corrosion of the heat transfer tube (superheater tube) is suppressed,
The life of the heat transfer tube can be extended. Moreover, it is not necessary to use a high-grade and expensive material for the heat transfer tube, and it is possible to use a more inexpensive material. (3) MgO, Mg (OH) ₂ , Mg during RDF production
By adding a Mg compound such as CO _3, it is no longer necessary to add a Ca compound that has been conventionally added, and by adding a Mg compound instead of a Ca compound, the ash amount becomes the same as that of the conventional one. It is more effective because the effect of corrosion inhibition is added while maintaining the above characteristics.

[Brief description of drawings]

FIG. 1 is a schematic structural explanatory view showing an apparatus for carrying out a method for recovering heat from a chlorine-containing combustible material according to a second embodiment of the present invention.

FIG. 2 is a schematic structural explanatory view showing an apparatus for carrying out a method for recovering heat from a chlorine-containing combustible material according to the first embodiment of the present invention.

[Explanation of symbols]

10 body 12, 14, 16 wind box 18 and 20 partitions 22 Combustion cell 24 circulation cells 26 heat transfer tube 28 heat collection cell 30, 32 supply nozzle 34 Solidifying device 36 molding machine 38 Dispersion plate with air nozzle

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI F23G 5/46 F23G 5/46 B // F23C 10/00 F23C 11/02 304 (72) Inventor Kakuya Takeda Chuo-ku, Kobe-shi Higashi-Kawasaki-cho 1-3-3 Kawasaki Heavy Industries, Ltd. Kobe Head Office (72) Inventor Masaki Kamimon 1-1 Kawasaki-cho, Akashi City, Hyogo Prefecture Kawasaki Heavy Industries, Ltd. Akashi Plant (72) Inventor Kakunori Kumagai Akashi, Hyogo Prefecture 1-1 Kawasaki-cho, Ichi, Kawasaki Heavy Industries, Ltd., Akashi Plant (72) Inventor Yuji Kamei 1-1-1, Kawasaki-cho, Akashi-shi, Hyogo Kawasaki Heavy Industries, Ltd., Akashi Plant (56) References: JP-A-7- 83422 (JP, A) JP-A-8-5069 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F23G 5/30 C10L 5/46 F23C 10/00 F22B 1/02 F22G 7/08 F23G 5/02 F23G 5/46

Claims (7)

(57) [Claims] 1. A method of recovering superheated steam using a chlorine-containing combustible material as a fuel in a superheater tube provided in a fluidized bed of a fluidized bed boiler, wherein chlorine-containing combustible material is MgO, Mg (O).
H) ₂ and MgCO ₃ at least
It is characterized by supplying a solidified fuel molded by adding one kind of magnesium compound to a fluidized-bed boiler to suppress corrosion of the superheater tube and recover superheated steam of 400 ° C. or higher in the superheater tube. A method of recovering heat from combustible substances containing chlorine. 2. A method for recovering heat from the chlorine-containing combustible material according to claim 1, wherein using a circulating fluidized bed boiler as a fluidized bed boiler. 3. The amount of magnesium compound added is 20 to 100% in terms of MgO, based on the ash content of the chlorine-containing combustible material.
The method for recovering heat from the chlorine-containing combustible material according to claim 1 or 2, wherein the amount of heat is added . 4. A method for producing a chlorine-containing combustible material used as a fuel for a fluidized bed boiler for recovering superheated steam of 400 ° C. or higher in a superheater tube while suppressing corrosion of the superheater tube provided in the fluidized bed. The solidified fuel, which has been dried, crushed, and separated into nonflammable substances, is a chlorine-containing combustible substance, and MgO, Mg (O
H) ₂ and MgCO ₃ at least
A solidified fuel produced from a chlorine-containing combustible material, which is formed by adding one kind of magnesium compound. 5. The amount of magnesium compound added is MgO.
The solidified fuel produced from the chlorine-containing combustible material according to claim 4, which is 2 to 10% of the solidified fuel in a converted amount. 6. The addition amount of magnesium compound is MgO.
The solidified fuel produced from a chlorine-containing combustible material according to claim 4 , which has an ash content of 20 to 100% of the chlorine-containing combustible material in a converted amount . 7. The solidified fuel produced from the chlorine-containing combustible material according to claim 4, 5 or 6 , wherein the chlorine-containing combustible material is municipal solid waste.