JP2003226569A - Structural material obtained by using ash of pressure- fluidized bed boiler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structural material obtained by using ash of a pressure- fluidized bed boiler, which is produced by inexpensively and efficiently utilizing the ash of the pressure-fluidized bed boiler, being discharged in a large amount, and which therefore contributes to environmental protection. <P>SOLUTION: The structural material is a block obtained by using the ash of the pressure-fluidized bed boiler as a main solid raw material and using, as a solidifying agent, any of solutions of liquid glass, potassium hydroxide and sodium hydroxide. Preferably, the structural material is obtained by adding a solution of the liquid glass or the like as the solidifying agent to a solid raw material mainly containing PFBC ash, then kneading them, pouring the kneaded fluid into a molding flask, solidifying the poured fluid by curing it in the molding flask for a predetermined period, removing the solidified block from the molding flask, and increasing the strength of the block by further curing the block removed from the molding flask for a predetermined period. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structural material using pressurized fluidized bed boiler ash that can be effectively used as a sidewalk block, a building material board and the like.

[0002]

2. Description of the Related Art As a coal-fired boiler for a coal-fired power generation facility or the like, a pulverized coal combustion boiler, which blows pulverized coal with air into a furnace and burns it under atmospheric pressure, is now widely used. Pressurized fluidized bed boilers have begun to be adopted with the aim of utilizing low-grade coal and improving power generation efficiency, and from the viewpoint of environmental protection. A pressurized fluidized bed boiler is a fluidized bed of fuel in which agglomerated coal and limestone are mixed and burned under pressure.Because the combustion temperature in the boiler can be lowered compared to a pulverized coal combustion boiler. , Nitrogen oxide (N
O _X) and sulfur oxides (less emissions SO _X), also, it is possible to use low-grade coal has the characteristic of high heat efficiency, coal ash discharged (hereinafter, abbreviated as PFBC ash Do)
The properties of are also significantly different from the conventional ones.

That is, a pulverized coal combustion boiler instantly burns pulverized coal at a high temperature of around 1500 ° C., whereas a pressurized fluidized bed boiler slowly burns at a low temperature of around 800 ° C. _No generation of _X , SO _X is absorbed by lime,
The PFBC ash discharged is a component rich in calcium and sulfur. Further, since the pulverized coal combustion boiler burns in a combustion region exceeding the melting point of ash, the ash discharged is collected in a glass state in a molten state, and the ash in the form of microspheres (such ash is traditionally It is called fly ash). On the other hand, the pressurized fluidized bed boiler does not exceed the melting point of ash due to low temperature combustion, and PFBC ash is a kind of fly ash, but it is recovered in the form of angular fine powder. The former mainly composed of glass but quartz (SiO ₂₎ and mullite _{(3Al 2 O 3 .2SiO 2)} , sometimes it contains small amounts of minerals, such as magnetite (Fe ₃ O _4). The latter is anorthite (CaO.Al
₂ O ₃ .2SiO ₂₎ and wollastonite _{(CaO.SiO 2) CaO-Al 2} O 3 -SiO 2 system other minerals, such as, hydroxyl Eresuta which they are bound to sulfur and water -
Which may include the phosphoramidite _{(6CaO.3SiO 2 .3CaSO 4 .CaO (OH} ) 2). In addition, lime exists in a free state, and PFBC ash is quicklime.
It is characterized by containing (CaO) and anhydrite (CaSO ₄ ).

The ash discharged from such a coal-fired boiler is large, and various effective utilization / resource-recycling techniques have been studied from the viewpoints of waste reduction, disposal cost reduction and environmental protection. Fly ash generated from pulverized coal combustion boiler is used for fly ash cement, cement raw material, road roadbed material, ground improvement material, civil engineering work, artificial lightweight aggregate, construction material board, etc., but most of them are added. Since it is used as an agent (material), it is not possible to use all of the fly ash discharged in large quantities, and the material strength, especially bending strength, is not very high, so it is difficult to use it as a structural material. There was also a problem. Therefore, the present inventor firstly added a sodium silicate aqueous solution to fly ash to form a block by room temperature curing or steam curing to obtain a structural material having high surface hardness and material strength (Japanese Patent Laid-Open No. 08-301).
639 publication).

On the other hand, as for the effective utilization and resource utilization technology of PFBC ash, which is a new fly ash, there are still few technologies that can be effectively implemented. For example,
Japanese Unexamined Patent Publication (Kokai) No. 11-172247 discloses a soil improving material containing 5 to 100% by weight of PFBC ash as an active ingredient.
Japanese Patent No. 1-147747 discloses a concrete composition in which approximately 50% by weight of cement is replaced by PFBC ash, but these conventional techniques are mainly used as an additive (material), and a large amount of PFBC is used. In order to make effective use of ash, it is necessary to develop other utilization technologies. Further, in JP-A-09-155314 and JP-A-09-075890, PFBC ash is compacted with a pressure molding machine to a particle size of 10 to 60 mm, and the molded product as it is or the molded product is crushed into particles. A method in which the diameter is adjusted to tens to hundreds of times that of coal ash, or a mixture of the two is mixed with fly ash and the like to be landfilled is disclosed, but this technology reduces volume for the purpose of reducing disposal costs. The processing method,
It does not make effective use of PFBC ash.

[0006]

SUMMARY OF THE INVENTION In view of the above situation related to the treatment of a large amount of pressurized fluidized bed boiler ash, the present invention can economically and effectively utilize the pressurized fluidized bed boiler ash. Aims to provide a structural material using pressurized fluidized bed boiler ash that can contribute to environmental protection.

[0007]

In order to achieve the above object, the inventors of the present invention have conducted extensive studies and as a result, have found that pressurized fluidized bed boiler ash is used as a main solid raw material and water glass solution or the like is used as a solidifying agent. The inventors have found that the solidified block can be used as a structural material, and completed the present invention. That is, the invention of claim 1 is a structural material using the pressurized fluidized bed boiler ash of the present invention, wherein the pressurized fluidized bed boiler ash is a main solid raw material, and the solid raw material is a water glass solution, caustic potash. The solution or the caustic soda solution is used as a solidifying agent to solidify into a block.

According to a second aspect of the present invention, the solid raw material is at least one of clay minerals such as blast furnace slag and kaolin.
A solid raw material containing 10 to 30% by weight, and
The present invention is a structural material using a pressurized fluidized bed boiler ash, wherein the solid raw material is a solid raw material containing 10 to 30% by weight of fly ash generated from a pulverized coal combustion boiler.

The invention of claim 4 relates to a preferred embodiment in the case where the solidifying agent is the water glass solution, wherein the water glass solution is a No. 1 water glass solution having a specific gravity of about 1.27 (chemical composition Na it is a structural material with ₂ O.2SiO _{2 .aq)} and the PFBC boiler ash.

The invention of claim 5 relates to a preferred manufacturing process, wherein the structural material using the pressurized fluidized bed boiler ash of the present invention is preferably a step of kneading by adding the solution to the solid raw material. A step of pouring the kneaded fluid into the mold, a step of curing the poured fluid in the mold for a predetermined period of time and solidifying, a step of releasing the solidified block body from the mold, and a step of releasing the block body. And a step of curing the material for a predetermined period of time to increase the strength of the material.

The invention of claim 6 relates to the preferred manufacturing process, wherein the curing in the step of solidifying and / or the curing in the step of increasing the material strength is a curing performed by leaving it to stand at room temperature and allowing it to cool. According to the invention of claim 7, the predetermined period of the solidifying step is approximately one day, and the predetermined period of the step of increasing the material strength is approximately 4 weeks, and the invention of claim 8 is A structural material using a pressurized fluidized bed boiler ash, wherein the kneading is performed using a vibration compaction molding device.

The invention according to claim 9 relates to a preferable material strength, and the structural material using the pressurized fluidized bed boiler ash of the present invention is preferably a cement mortar test JI.
It is a block body that has a bending strength of 5 MPa or more in a bending test according to S standard (4 × 4 × 16 cm, span distance 10 cm).

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Coal ash discharged from a pressurized fluidized bed boiler such as a coal-fired thermal power generation facility does not scatter with ash collected by an electric dust collector etc. There is ash that can be collected from the bottom of the boiler, and the pressurized fluidized bed boiler ash (PFBC ash) that is the main solid material in the present invention means the former, but the ash collected from the bottom of the latter is the ash. It can be effectively used as an auxiliary material of the invention.

The present inventor has long been engaged in research aimed at obtaining a structural material that can be used as a useful industrial material by solidifying industrial waste and the like, and as already mentioned above, a structure obtained by solidifying fly ash has already been formed. A material (Japanese Patent Laid-Open No. 08-301639) has been proposed, and a structural material (Japanese Patent Laid-Open No. 08-301638) obtained by solidifying kaolin powder has been proposed.

The present invention is based on such many years of research, and is manufactured by a simple manufacturing process in which PFBC ash is used as a main solid material, water glass solution or the like is used as a solidifying agent, and the mixture is left to stand at room temperature and allowed to cool. It was discovered that the block body has a high material strength and can be used as a structural material such as a sidewalk block or a building material board. That is, the structural material using the pressurized fluidized bed boiler ash of the present invention uses the pressurized fluidized bed boiler ash as a main solid raw material, and a water glass solution, a caustic potash solution, or a caustic soda solution is used as a solidifying agent. Is used as a solidified block body, and the block body can be used as a structural material such as a sidewalk block or a building material board.

At that time, 10 to 30% by weight of at least one clay mineral such as blast furnace slag or kaolin is used as a solid raw material.
By adding, the material strength of the structural material of the present invention can be improved. The weight% to be added is not particularly limited to the present invention, but if it is less than 10% by weight, it is difficult to obtain the improvement of the material strength, and it is costly to increase the ratio to be added more than 30% by weight. At the same time, it does not fit the purpose of the present invention of effectively utilizing as much PFBC ash as possible.

As described above, the present invention can also be carried out as a solid raw material to which 10 to 30% by weight of fly ash generated from a pulverized coal combustion boiler which has not been effectively utilized yet is added. The weight% to be added is not particularly limited to the present invention, but if it is less than 10% by weight, the amount of fly ash used is reduced, and if it is more than 30% by weight, the material strength, particularly the bending strength is lowered.

When a water glass solution is used as the solidifying agent, for example, No. 3 water glass (chemical composition Na ₂ O.3SiO ₂ .aq)
Etc., all water glass (1
No. 2, No. 3, No. 4, and No. 4) are not limited to the present invention, No. 1 and No. 3 are preferable, and No. 1 water glass solution is particularly preferable. The specific gravity is preferably about 1.27. When a solution having a low concentration is used, the period required for curing becomes longer, and when a solution having a higher concentration is used, the material strength of the obtained structural material is improved, but there are problems such as high cost and increased power required for kneading.

Next, a preferable manufacturing process for obtaining a structural material using the PFBC ash of the present invention will be described. The structural material of the present invention is, for example, kneaded by adding a water glass solution or the like as a solidifying agent to a solid raw material mainly consisting of PFBC ash, pouring the kneaded fluid into a mold, and curing the poured fluid for a predetermined period in the mold. Then, the solidified block body is released from the mold, and the released block body is cured for a predetermined period of time to increase the material strength. In addition, after curing in the mold for a predetermined period of time and solidifying, the mold is not released from the mold, and the material is further cured for a predetermined period of time to increase the material strength, and then the product is released from the mold. Although it is possible, it is desirable to release the mold in as short a time as possible and increase the operating rotation rate of the mold, and it is preferable to carry out curing in two stages as described above. The amount of solidifying agent added to the solid raw material is
The type and concentration of the solidifying agent to be used, the presence or absence of the sub-solid raw material and its type and addition amount are parameters to be selected according to various conditions, and the present invention is not limited, for example, the specific gravity is approximately 1.27. When the PFBC ash is solidified using the No. 1 water glass solution, the weight ratio of the No. 1 water glass solution to the PFBC ash is preferably about 0.75: 1.

Curing when solidifying in the mold and curing when increasing the material strength can be carried out by an extremely simple method of leaving it to stand at room temperature and allowing it to cool. The kind of the agent, which is a parameter to be selected according to various conditions, is not intended to limit the present invention, for example, when the PFBC ash is solidified using a No. 1 water glass solution having a specific gravity of approximately 1.27, The former curing period is about 1
It is preferable that the curing period for the latter days is about 4 weeks, which makes it possible to obtain structural materials that can be used for sidewalk blocks, building board, and the like. The kneading is not particularly limited to the present invention, but it is preferable that the kneading is performed using a vibration compaction molding device rather than using a kneading flow molding device. A solid material ratio can be reduced, and a structural material having dramatically high material strength can be obtained.

The structural material using the PFBC ash of the present invention obtained by such an embodiment is a JIS standard (4 × 4 × 4) for cement mortar test, although it depends on the component composition of the solid raw material and the type of the solidifying agent used. It can be obtained as a block body having a bending strength of 5 MPa or more by a bending test with 16 cm and a span distance of 10 cm, which means that it is a structural material having a bending strength that can be used as a sidewalk block.

According to the embodiment described in detail above,
The present invention, PFBC ash, which has conventionally been landfilled with much labor and cost, is a very simple manufacturing process in which it is left standing and cooled at room temperature using a water glass solution or the like as a solidifying agent. It is provided as a block body that can be used for sidewalk blocks, building material boards, etc., and can pressurize fluidized bed boiler ash discharged in large quantities economically and effectively, and further contribute to environmental protection. A structural material using ash can be provided.

[0023]

EXAMPLES The present invention will be specifically described below with reference to examples, but it goes without saying that the present invention is not limited to these examples.

The solid raw materials used in this example were PFBC ash discharged from the pressurized fluidized bed boiler and fly ash discharged from the pulverized coal combustion boiler, and their chemical compositions (% by weight) are shown in Table 1. The physical properties are shown in Table 2. Also, FIG.
Fig. 2 and Fig. 2 show the particle size distributions of PFBC ash discharged from the pressurized fluidized bed boiler and fly ash discharged from the pulverized coal combustion boiler, which were measured by a laser diffraction particle size distribution analyzer. In the table, (A) means PFBC ash and (B) means fly ash. The same applies hereinafter. In addition, LOI in Table 1 means ignition loss.

[0025]

[Table 1]

[0026]

[Table 2] The solidifying agent used is a No. 1 water glass solution (chemical composition Na ₂ O.2SiO ₂ .aq) having a specific gravity of 1.27.

Table 3 shows the blending ratio of the solid raw materials (PFBC (A) and fly ash (B)) used in this example, and the weight ratio of the solid raw materials and the No. 1 water glass solution added thereto.

[0028]

[Table 3] Knead each prepared sample for 2 minutes at room temperature using a spatula, pour the kneaded fluid into a mold (dimensions: 2 x 2 x 8 cm), leave it for about 1 day at room temperature and let it cool. A solidified block body was obtained. Note that three block bodies were prepared for each sample in order to measure the relationship between the curing period and the bending strength. Then, the block body was released from the mold, allowed to stand at room temperature and allowed to cool, and the bending strength was measured as a relationship with the curing period.

The bending strength was measured by 1 manufactured by Tokyo Test Mfg. Co., Ltd.
A ton material tester, serial number 19888, was used, and a span distance was set to 5 cm, and three pieces were taken. The results are shown in Table 4. The bending strength in Table 4 is the average value of the three-point bending test, and its unit is MPa. For the convenience of the experiment, the bending strength of this example was measured with a half size of the JIS standard (4 × 4 × 16 cm, span distance 10 cm) of the cement mortar test described above, and the measurement was slightly performed. The accuracy is reduced, but a large error does not occur.

[0030]

[Table 4] Table 4 shows that the bending strength tends to decrease as the proportion of fly ash increases, but no drastic decrease occurs up to 20% by weight (PF08), and the bending strength that can be used as a sidewalk block is approximately 4 weeks. It shows that structural materials of MPa or higher can be obtained. In contrast, 30 fly ash
When it is more than 10% by weight (PF07), the bending strength is greatly reduced, and the systematic relationship between the mixing ratio of fly ash and the bending strength is lost, and structural materials that require high bending strength. It is not suitable for the condition to obtain.

According to the present example, No. 1 water glass solution was added as a solidifying agent to a solid raw material obtained by adding fly ash to PFBC ash in an amount of up to 20% by weight, and the mixture was kneaded, and the kneaded fluid was poured into a mold. Let stand for 1 day at room temperature, let it cool, let it solidify, release the solidified block from the mold, and let it stand for 4 weeks.
A structural material with high material strength that can be used as a sidewalk block was obtained by an extremely simple manufacturing process of leaving it to stand at room temperature and allowing it to cool. That is, according to this example, a structural material using a pressurized fluidized bed boiler ash that can economically and effectively use a large amount of pressurized fluidized bed boiler ash and that contributes to environmental protection is provided. be able to.
Although the embodiments of the present invention have been described above, without departing from the spirit and scope of the present invention defined in the claims,
Obviously, various changes may be made in the form and details.

For example, in the examples, a specific gravity of 1.
I explained the example using No. 1 water glass solution of 27,
Different concentrations may be used, a water glass solution other than the No. 1 water glass solution, for example, No. 3 water glass solution may be used, and further, a caustic potash solution or caustic soda other than the water glass solution may be used. You may use a solution.

In the examples, fly ash generated from a pulverized coal combustion boiler was used as an auxiliary material. However, clay minerals such as blast furnace slag or kaolin may be added, in which case 10 to 30 wt. %, It is preferable to add it in the range of%, so that the material strength of the obtained structural material can be increased.

[0034]

INDUSTRIAL APPLICABILITY The present invention is a very simple method of leaving PFBC ash, which was conventionally landfilled with great labor and cost, at room temperature and allowing it to cool, using a water glass solution or the like as a solidifying agent. It is provided as a block body that can be used for sidewalk blocks, building material boards, etc. by various manufacturing processes, and it is possible to economically and effectively use a large amount of pressurized fluidized bed boiler ash, which can also contribute to environmental protection. There is an effect that a structural material using the pressurized fluidized bed boiler ash can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing a particle size distribution of PFBC ash discharged from a pressurized fluidized bed boiler used in an example of the present invention.

FIG. 2 is a diagram showing a particle size distribution of fly ash discharged from a pulverized coal combustion boiler used in an example of the present invention.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C04B 18:14 C04B 18:14 A 14:10 14:10 Z 18:08 18:08 Z 22:06) 22:06 Z (72) Inventor Noboru Shintani 4-33 Komachi, Naka-ku, Hiroshima City, Hiroshima Prefecture F-Term (Reference) China Electric Power Company 4G012 PA06 PA26 PA27 PA29 PB03 PC04 PE07 RB03

Claims (9)

[Claims] 1. A block body obtained by using pressurized fluidized bed boiler ash as a main solid raw material, and solidifying the solid raw material by using either a water glass solution, a caustic potash solution or a caustic soda solution as a solidifying agent. A structural material using pressurized fluidized bed boiler ash, which is characterized. 2. The pressurized fluidized bed boiler ash according to claim 1, wherein the solid raw material is a solid raw material containing 10 to 30% by weight of at least one of clay minerals such as blast furnace slag and kaolin. The structural material used. 3. The pressurized fluidized bed boiler ash according to claim 1 or 2, wherein the solid raw material is a solid raw material containing 10 to 30% by weight of fly ash generated from a pulverized coal combustion boiler. Structural material using. 4. The water glass solution has a specific gravity of about 1.27.
Construction material using the PFBC boiler ash according to any one of claims 1 to 3, characterized in that one water glass solution (chemical composition Na ₂ O.2SiO ₂ .aq). 5. The structural material comprises the steps of adding the solution to the solid raw material and kneading, pouring the kneaded fluid into a mold, and curing the poured fluid in the mold for a predetermined period of time to solidify. And a step of releasing the solidified block body from the mold, and a step of curing the released block body for a predetermined period of time to increase the material strength. A structural material using the pressurized fluidized bed boiler ash according to any one of claims 1 to 4. 6. The pressurized flow according to claim 5, wherein the curing in the step of solidifying and / or the curing in the step of increasing the material strength is a curing performed by leaving it to stand at room temperature and allowing it to cool. Structural material using floor boiler ash. 7. The method according to claim 5, wherein the predetermined period of the solidifying step is approximately one day, and the predetermined period of the step of increasing the material strength is approximately four weeks.
A structural material using the described pressurized fluidized bed boiler ash. 8. The structure using the pressurized fluidized bed boiler ash according to claim 5, wherein the kneading is kneading performed using a vibration compaction molding device. material. 9. The block material having a bending strength of 5 MPa or more in a bending test according to JIS standard (4 × 4 × 16 cm, span distance 10 cm) of cement mortar test, wherein the structural material is a block body. A structural material using the pressurized fluidized bed boiler ash according to claim 8.