KR102424124B1 - Granular fluid media having a function of reducing fine dust in a fluidized bed combustion furnace, a method of manufacturing the same, and a method of operating the fluidized bed combustion furnace using the same - Google Patents

Abstract

A fluid medium for a fluidized bed boiler that can replace fluidized sand, comprising: 30 parts by weight to 95 parts by weight of kaolin; 1 part by weight to 20 parts by weight of expanded pearlite; and 0.1 parts by weight to 10 parts by weight of bentonite; a granular fluid medium having an average particle diameter of 100 μm to 500 μm is disclosed. The granular fluid medium provided in one aspect of the present invention has the effect of reducing fine dust, improving the heat exchange efficiency of the boiler, and saving fluidization energy.

Description

Granular fluid media having a function of reducing fine dust in a fluidized bed combustion furnace, a method of manufacturing the same , and a method of operating the fluidized bed combustion furnace using the same}

The present invention relates to a granular fluid medium having a function of reducing fine dust in a fluidized bed furnace, a method for manufacturing the same, and a method for operating a fluidized bed furnace using the same.

As the population is concentrated and industrial facilities are advanced, power resources consumed have greatly increased, so thermal power generation facilities have become essential facilities, but they are becoming a fixed source of pollution that emits harmful air pollutants including particulates. In recent years, as the use of unused energy sources for fuels used in thermal power plants has become more active, combustible solid waste fuels (SRF), wood chips and biofuels (bio-SRF) represented by wood pellets, etc. use is increasing significantly.

These solid fuels, among the fine particulate matter, which are harmful air pollutants including particulates emitted during the combustion process, are mostly filtered out in the nasal passages and cause respiratory diseases such as rhinitis, whereas PM-10 (air It is known that fine and ultra-fine particles such as particulate matter with a mechanical diameter smaller than 10 microns) and PM-2.5 (particulate matter with aerodynamic diameter less than 2.5 micron) can penetrate deep into the alveoli and cause immune diseases.

Recently, as each country as well as domestic local governments are strengthening the emission standards for fine dust from thermal power plants, a lot of investment is required for reducing fine dust emission from thermal power plants in order to meet the requirements.

In air pollution prevention facilities, an electric dust collector, a bag filter using a filter cloth, and a washing system using water are used alone or in combination. It may be advantageous in terms of effectiveness or in a method of resolving difficulties in equipment and operation to reduce the occurrence of

As a method to solve the problem of fine dust emitted from such a fluidized bed combustion furnace, research is being conducted on improving the structure of the combustion furnace device, changing the operating conditions, changing the dust collection system, and improving the dust collection capacity of the filter cloth. There is a problem in that it is difficult to secure the operating economy of the combustion furnace because changing the material or structure of the device or improving the filter dust collection performance involves a lot of facility investment. Therefore, as a method that has been recently developed, a method for reducing fine dust using additives is being developed.

In addition, since most SRF fuels have relatively low calorific value, the ratio of using a fluidized bed combustor with excellent combustion efficiency is higher than that of conventional boilers such as rotary kiln and stocker type. Fluidized bed combustion furnace is a mechanism that burns the introduced fuel particles in a suspended state while blowing air from the lower part of the combustor. Fluidized bed furnaces are the most recently constructed combustion systems in Korea.

In such a fluidized bed combustion furnace, it is necessary to use a fluidized medium that forms a fluidized bed for smooth combustion of the introduced fuel. As a conventional fluidized medium, silica sand having a particle size of 0.1 to 1.0 mm is mainly used.

However, as is known, since sand has a high hardness (based on Mohs hardness = 7.0), there may be a problem of abrasion of structures such as the inside of the combustion furnace and heat transfer tubes, and the specific gravity of the fluid is 2.6 to 2.8. The high consumption of operating energy of the blower introduced to make it flow is still a problem, but there is still no record of developing alternative materials for this.

As a technique for reducing fine dust so far, a method for reducing the emission of fine dust and harmful gas by spraying a slurry or liquid additive into the combustion furnace or the rear end of the furnace has been proposed.

For example, in Korean Patent Registration No. 10-1918519 (2019.02.08.), in “a device for reducing fine dust in incineration facilities,” fuel accelerators (sodium hydroxide, calcium hydroxide, hydrogen peroxide, boron, sodium borate, glycerin and water) ), it was suggested that the emission of PM10 and PM2.5 could be reduced by 39% and by 40% by incineration while spraying directly into the combustion chamber as a solution.

In addition, in Republic of Korea Patent No. 10-2067720 (2020.02.11.), in “additive composition for solid fuel”, aluminum hydroxide nanoparticles, magnesium oxide nanoparticles, vanadium-titanium-based composite oxide, magnesium ferrite nanoparticles, and paraffinic oil It is suggested that the effect of removing 42% of the NOx and 50% of the SOx emitted by burning the product in a slurry state and directly adding/injecting it to the solid fuel is proposed.

In addition, as for the fine dust reduction device, in Korean Patent Laid-Open No. 10-2018-0130659 (2018.12.10.), in the “fine dust reduction device”, the fine dust is removed by inducing combustion gas discharged into the chimney and spraying water. It is suggested to install a separate facility for

However, since the proposed techniques use a liquid or a slurry in which nanoparticles are dispersed, there is a problem of introducing a separate injection facility, and there are problems such as that the thermal shock inside the combustor cannot be avoided due to the introduction of the solution.

Republic of Korea Patent No. 10-1918519 Republic of Korea Patent Registration No. 10-2067720 Republic of Korea Patent Publication No. 10-2018-0130659

It is an object of the present invention to provide a fluidized medium for a granular fluidized bed boiler that can replace fluidized sand and effectively reduce fine dust.

In order to achieve the above object, in one aspect of the present invention

As a fluid medium for a fluidized bed boiler that can replace fluidized sand,

30 parts by weight to 95 parts by weight of kaolin;

1 part by weight to 20 parts by weight of expanded pearlite; and

0.1 parts by weight to 10 parts by weight of bentonite;

including,

A granular fluid medium having an average particle diameter of 100 μm to 500 μm is provided.

In addition, in another aspect of the present invention

mixing 30 parts by weight to 95 parts by weight of kaolin powder, 1 part by weight to 20 parts by weight of expanded pearlite powder, and 0.1 parts by weight to 10 parts by weight of bentonite powder; and

granulating and molding the mixed kaolin powder, expanded pearlite powder and bentonite powder to have an average particle diameter of 100 μm to 500 μm;

There is provided a method for producing the granular fluid medium of claim 1 comprising a.

Furthermore, in another aspect of the present invention

There is provided a fluidized bed combustion furnace operating method, characterized in that 0.01 to 2.0 parts by weight of the granular fluid medium is used based on 100 parts by weight of fuel.

The granular fluid medium provided in one aspect of the present invention has the effect of reducing fine dust, improving the heat exchange efficiency of the boiler, and saving fluidization energy.

1 is an image showing the shape of a granular fluid medium according to an embodiment of the present invention;
2 is an image showing the shape of a conventional floating sand according to a comparative example of the present invention;
3 is a graph showing the particle size distribution of a granular fluid medium according to an embodiment of the present invention;
4 is a graph showing the particle size distribution of a conventional flow sand according to a comparative example of the present invention;
5 is a graph showing the particle size distribution of fly ash when a fluidized bed combustion furnace is operated using an embodiment and a comparative example of the present invention;
6 is a graph showing the particle size distribution of fly ash when a fluidized bed combustion furnace is operated using another embodiment and a comparative example of the present invention;
7 is a graph showing the particle size distribution of fly ash when a fluidized bed combustion furnace is operated using another embodiment and a comparative example of the present invention;
8 is a graph simultaneously showing the particle size distribution of fly ash when the fluidized bed combustion furnace is operated using the Examples and Comparative Examples of FIGS. 5 to 7 .

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

In one aspect of the invention

As a fluid medium for a fluidized bed boiler that can replace fluidized sand,

30 parts by weight to 95 parts by weight of kaolin;

1 part by weight to 20 parts by weight of expanded pearlite; and

0.1 parts by weight to 10 parts by weight of bentonite;

including,

A granular fluid medium having an average particle diameter of 100 μm to 500 μm is provided.

Hereinafter, the granular fluid medium provided in one aspect of the present invention will be described in detail for each configuration.

First, the granular fluid medium provided in one aspect of the present invention includes kaolin.

The granular fluid medium may contain 30 parts by weight to 95 parts by weight of the kaolin. Preferably it may contain 40 parts by weight to 90 parts by weight, and more preferably 45 parts by weight to 85 parts by weight.

The kaolin may contain an alumina component of 20 wt% or more, preferably 25 wt% or more.

Next, the granular fluid medium provided in one aspect of the present invention includes expanded perlite.

The granular fluid medium may contain 1 to 20 parts by weight of the expanded pearlite, preferably 3 to 20 parts by weight, more preferably 5 to 15 parts by weight.

When the expanded perlite is included in an amount of less than 1 part by weight, the specific gravity of the granular fluid medium exceeds 1.8, so there is a problem that it is difficult to expect the effect of reducing flow energy. If the specific gravity of the granular fluid medium is less than 1.2, it may not flow sufficiently and may be blown off.

Next, the granular fluid medium provided in one aspect of the present invention includes bentonite.

The granular fluid medium may contain 0.1 to 10 parts by weight of bentonite, preferably 1 to 10 parts by weight, more preferably 2 to 10 parts by weight.

When the bentonite is included in an amount of less than 0.1 parts by weight, the compressive strength of the granular fluid medium is too low, and thus a problem that it may be crushed at the initial stage of fluidization may occur. is too high, which may cause a problem that the contact reaction rate with fine dust formed and scattered in the combustion furnace may be low.

In addition, the granular fluid medium provided in one aspect of the present invention may further include at least one material selected from the group consisting of coal fly ash and zeolite.

The coal fly ash and zeolite are materials having excellent porosity, and may improve the collecting power of fine dust.

The granular fluid medium may further include 5 to 30 parts by weight of at least one material selected from the group consisting of coal fly ash and zeolite, and preferably 7 to 25 parts by weight.

When the content of at least one material selected from the group consisting of coal fly ash and zeolite is less than 5 parts by weight, the conversion rate of the specific surface area of the granular fluid medium is low, so it may be difficult to expect the effect of adding the porous material. This may occur, and when the zeolite is included in more than 30 parts by weight, the degree of abrasion of the granular fluid medium is too low, and thus there may be a problem that it may be easily disintegrated.

The average particle diameter of the granular fluid medium provided in one aspect of the present invention may be 100 μm to 1000 μm, preferably 100 μm to 500 μm.

When the average particle diameter of the granular fluid medium is less than 100 μm, when it is introduced into the combustion furnace as a fluid medium, a problem that a fluidized bed cannot be formed and floated initially and discharged to the rear end of the cyclone may occur, and the average particle diameter is 1000 If it exceeds ㎛, it may be difficult to actively flow, and there may be problems that it may be difficult to sufficiently contact fine dust generated during combustion.

Here, the more uniform the particle size distribution of the fluidizing medium, the more efficient the flow phenomenon can be induced. This is because, if the particle size distribution is wide, the number of individuals flowing due to a constant air inflow velocity decreases and it is difficult to secure a large flow area.

In addition, the granular fluid medium may be spherical. By having a spherical particle shape, a uniform flow phenomenon can be exhibited by the air flow rate.

The specific gravity of the granular fluid medium provided in one aspect of the present invention may be 1.0 to 1.8, preferably 1.2 to 1.6. The specific gravity of the granular fluid medium provided in one aspect of the present invention is reduced by 10% to 20% compared to the silica sand used as the conventional fluidized sand, thereby reducing the flow energy.

The compressive strength of the granular fluid medium provided in one aspect of the present invention may be 10 kgf to 25 kgf, preferably 15 kgf to 20 kgf.

If the compressive strength exceeds 25 kgf, the disintegration of the fluid medium does not occur well, so there may be a problem that the contact reaction rate with fine dust formed and scattered in the combustion furnace may be lowered, and if the compressive strength is less than 10 kgf , may be excessively pulverized at the initial stage of fluidization, and due to such pulverization, the time to act as a fluid medium is short, which may cause a problem that the consumption rate of the fluid medium may be excessively high.

Characteristics of the fluid medium provided in one aspect of the present invention may be continuously abraded or disintegrated while flowing in the combustion furnace and dispersed into fine particles, and various Since it is collected in contact with gaseous materials, the fluid medium is disintegrated by using porous materials, and while it is scattered, the property of collecting them in contact with the gas generated in the combustion furnace can be expressed.

To this end, the fluid medium provided in one aspect of the present invention includes zeolite, coal fly ash, bentonite, expanded pearlite, etc., known as porous materials, and the specific surface area of the fluid media formed by combining them is 40 compared to the conventional silica sand fluid media. It can have more than double the specific surface area, and the compressive strength is as low as 40%, so that it is possible to reduce the abrasion of the internal structure of the combustion furnace. In addition, the flow energy can be reduced by lowering the specific gravity of the fluid medium by about 10 to 20% compared to the conventional silica sand.

In addition, the fluid medium provided in one aspect of the present invention reacts and collects the low-melting-point salt generated in the combustion process until it is discharged from the combustion furnace through the heat exchanger to react and collect, so it is possible to effectively reduce the low-melting salt.

More specifically, the granular fluid medium provided in one aspect of the present invention includes natural porous materials, which are materials based on aluminum silicate, and have reactivity with low-melting salts such as potassium and sodium.

That is, since the components included in the granular fluid medium are converted into materials of high melting point by reaction with low melting point salts (K, Na) as shown in Formulas 1 and 2 below, the effect of blocking the formation of slag is reduced. In addition, the porous material has the effect of collecting fine dust formed in the combustion furnace.

Al ₂ O ₃ ·2SiO ₂ ·H ₂ 0 + 2KCl → K ₂ O(orNa ₂ O) ·Al ₂ O ₃ ·2SiO ₂ + 2HCl (Formula 1)

Al ₂ O ₃ ·2SiO ₂ ·H ₂ 0 + 2SiO ₂ + 2KCl→ 2KAlSi ₂ O ₆ + H ₂ O + 2HCl (Formula 2)

That is, fine dust can be effectively reduced by using substances capable of chemically reacting with fine dust as a fluid medium and capable of physically collecting fine dust at the same time.

In addition, the granular fluidized medium provided in one aspect of the present invention can reduce the fluidization energy by producing a low specific gravity of the fluidized medium essential in the fluidized bed combustion furnace and maximize the heat transfer efficiency by increasing the fluidization height. In addition, it is possible to solve the problem of abrasion of the structure inside the combustion furnace by the flowing sand used as the existing fluid medium.

In another aspect of the invention

mixing 30 parts by weight to 95 parts by weight of kaolin powder, 1 part by weight to 20 parts by weight of expanded pearlite powder, and 0.1 parts by weight to 10 parts by weight of bentonite powder; and

granulating and molding the mixed kaolin powder, expanded pearlite powder and bentonite powder to have an average particle diameter of 100 μm to 500 μm;

There is provided a method for producing the granular fluid medium comprising a.

Hereinafter, the manufacturing method of the granular fluid medium provided in another aspect of the present invention will be described in detail for each step. However, since the granular fluid medium has been described above, it may be omitted without overlapping description.

First, the method for preparing a granular fluid medium provided in another aspect of the present invention includes mixing kaolin powder, expanded pearlite powder and bentonite powder.

In the above step, 30 parts by weight to 95 parts by weight of kaolin powder, 1 part by weight to 20 parts by weight of expanded pearlite powder, and 0.1 parts by weight to 10 parts by weight of bentonite powder may be mixed.

The maximum particle size of the powders may be 35 μm to 200 μm, preferably 45 μm to 150 μm.

The mixing method in the above step is not limited to a specific method.

Next, the method for producing a granular fluid medium provided in another aspect of the present invention comprises the steps of granulating and molding the mixed kaolin powder, expanded pearlite powder and bentonite powder to have an average particle diameter of 100 μm to 500 μm. do.

In one embodiment, the granulation and molding of the step may be performed using a granulator and a kneader, but is not limited to a specific method.

In the case of granulation in a granulator, the step of drying the assembled molded body at 100° C. to 150° C. may be further included. The drying may be performed for a time of 30 minutes to 60 minutes.

After the drying, the step of separating the sieve may be further included. At this time, particles of 100 μm or less can be reused by putting them back into the granulator as a seed for granulation, and particles of 500 μm or more can be re-ground with a grinder and reused as raw materials for granulation.

In another aspect of the invention

There is provided a fluidized bed combustion furnace operating method, characterized in that 0.01 to 2.0 parts by weight of the granular fluid medium is used based on 100 parts by weight of fuel.

As the granular fluid medium and its manufacturing method have been described above, it may be omitted without overlapping description.

In the fluidized bed combustion furnace operating method provided in another aspect of the present invention, the granular fluid medium may be used in an amount of 0.01 parts by weight to 2.0 parts by weight based on 100 parts by weight of the fuel. The fuel may be solid waste fuel (SRF) or bio-solid fuel (bio-SRF).

When the amount of the granular fluid medium is less than 0.01 parts by weight based on 100 parts by weight of the fuel, there may be a problem that the fine dust reduction efficiency is too low, and if it exceeds 2.0 parts by weight, there are too many fluid media flowing inside the combustion furnace There may be problems that impair efficient combustion and heat transfer efficiency.

In the fluidized bed combustion furnace operating method provided in another aspect of the present invention, the average particle size of fly ash collected in a bag filter may be 60 μm or more, preferably 80 μm or more, and more preferably It may be 150 μm or more.

In addition, in the fluidized bed combustion furnace operating method provided in another aspect of the present invention, the content of PM10 or less particles of fly ash collected in a bag filter may be less than 20%, preferably less than 15%, More preferably, it may be less than 10%.

The fluidized bed combustion furnace operation method can cause the particles in the bag filter to form a relatively large particle size, and by reducing PM10, it is possible to greatly improve the collection efficiency of the bag filter.

Hereinafter, the present invention will be described in more detail through Examples, Comparative Examples and Experimental Examples. The scope of the present invention is not limited to specific embodiments, and should be construed by the appended claims. In addition, those skilled in the art will understand that many modifications and variations are possible without departing from the scope of the present invention.

<Example 1>

After mixing 60~90 wt% of kaolin powder, 5~20 wt% of expanded pearlite powder, and 5~10 wt% of bentonite powder, it was granulated using a granulator. In particular, kaolin has a true specific gravity of 2.6, an apparent specific gravity of 0.45, and a maximum particle size of 43 μm.

At this time, the granulated compact assembled in the granulator was dried at 105 to 150° C. for 30 to 60 minutes, sieved, and particles with a particle size of 100 μm or less and 500 μm or more were re-ground and reused as raw materials for granulation. In addition, the particle size of the manufactured granulated article was adjusted to be 100 μm or more and 500 μm or less.

In the case of using kaolin alone, the specific gravity cannot be controlled, so expanded pearlite was used to control the specific gravity, and bentonite was used to impart strength to the granular fluid medium. 1 shows for Example 1. FIG.

<Example 2>

In the same manner as in Example 1, a granular fluid medium was prepared, but for conversion of physical properties such as specific surface area, abrasion resistance, and specific gravity, 60 to 90% of kaolin was used as the central material and coal fly ash, a material having a higher specific surface area than kaolin, was used 5 to 30%, bentonite was used within the range of 5 to 10% to control compressive strength, and expanded pearlite was used to control within the range of 5 to 20% for specific gravity control.

<Example 3>

A granular fluid medium was prepared in the same manner as in Example 1, but with 60 to 90% kaolin as a central material, and in order to further improve the effect obtained in Example 2, zeolite powder known as a material having a higher fine specific surface area than coal fly ash 5-30 wt% was further added. Bentonite for compressive strength control was used within 5-10 wt%, and expanded pearlite for specific gravity control was used within 5-20 wt%.

<Comparative Example 1>

Silica sand, a fluid sand used as a fluid medium in the past, was used.

2 shows an image for Comparative Example 1.

<Experimental Example 1> Measurement of physical properties

For Examples 1 to 3 and Comparative Example 1, compressive strength, abrasion, specific surface area, specific gravity, etc. were measured, and are shown in Table 1 below.

The wear level was measured using the method of D5757-95, the American Standard Test Method (ASTM), which is a method for measuring the wear level of solid catalysts applicable to the fluidized bed process, and determines the general wear index (AI) and modified wear index (CAI). Therefore, it is used to indicate the wear level of the particles.

At this time, the wear index (AI) is measured in a small batch type fluidized bed and is calculated as the rate of solid loss due to wear after 5 hours as shown in Equation 1 below.

<Equation 1>

AI(5) = [F(5)/S] × 100

Here, S is the initial weight of the solid layer, and F(5) is the weight of scattering loss solids collected in the fine powder collector for 5 hours.

The specific gravity of the fluid medium was measured using Equation 2 below, which is a general method for measuring the specific gravity of a solid.

<Equation 2>

Specific gravity = (weight in air)/ (weight in air)-(weight in water)

Compressive strength was measured using a compressive strength measuring device (multitest-xt, Coretech Korea).

In addition, the specific surface area was measured using an auto blaine permeability tester, and this measurement method used the standard of KS L 5106 (a method for testing the fineness of Portland cement using an air permeability device).

compressive strength
(kgf) wear and tear
(%) specific surface area
(cm2/gr) importance Comparative Example 1 38.75 0.014 150 1.83 Example 1 18.47 38.56 6100 1.65 Example 2 17.34 42.25 7830 1.47 Example 3 17.79 40.84 8420 1.45

In the case of Example 1, compared to Comparative Example 1, the specific surface area was increased by 40 times and the specific gravity was adjusted to be reduced by about 10%, and the granular fluid medium of Example 1 increased the abrasion level to 38%. It can wear and break during flow.

In the case of Example 2, compared to Comparative Example 1, the specific surface area was enlarged 52 times, the specific gravity was adjusted to be reduced by about 20%, and the compressive strength was lowered by 54% (in this case, the compressive strength was 17.34 kgf). These physical properties are for measuring the effect change when the specific surface area is greatly improved compared to the case of Example 1, and for this purpose, coal fly ash having a high specific surface area is further added. In addition, the fluid medium of Example 2 may be abraded and disintegrated during flow by increasing the abrasion level to 42% compared to the silica sand of Comparative Example 1.

In the case of Example 3, compared to Comparative 1, the specific surface area was enlarged by 55 times, the specific gravity was adjusted to be reduced by about 20%, and the compressive strength was lowered by 54%. In addition, the fluid medium of Example 3 can be worn and disintegrated during flow by raising the abrasion level to a level of 40%.

<Experimental Example 2> Confirmation of fluid medium operation result

In order to confirm the effect of reducing operating energy and reducing fine dust for Examples 1 to 3 and Comparative Example 1, a pilot plant-grade fluidized bed combustion furnace (0.1 MW _th grade circulating fluidized bed (CFBC) combustion furnace) installed at the Korea Energy Research Institute was used. was used.

Since the circulating fluidized bed combustion facility has a furnace height of 10 m and a diameter of 0.15 m, the input of the fluid medium of the Examples was about 20 kg to maintain a height of 70 cm above the air distribution plate installed at the bottom of the furnace. This maintains the same volume as when the conventional silica sand is added as in Comparative Example 1, but the weight is about 10% less.

Under these conditions, imported wood pellet fuel from Indonesia was used, and the various effects of the fluid were measured while the furnace was continuously operated for 30 hours after the furnace was adjusted to the normal operating state.

The first effect of using the fluidizing medium of the examples is that the energy required for fluidization is reduced compared to the comparative examples.

The amount of air introduced for fluidization is controlled by the rotation speed of the fan. In the case of Examples, the fluidization height must be reduced to 1650 rpm, which corresponds to a decrease of about 10% from 1850 rpm for the flow of Comparative Example 1 to increase the fluidization height to the combustion furnace height can be maintained at the level of 90% of From this, it can be seen that, when the fluid medium of the embodiments is used, the energy required for the operation of the fan is reduced by operating the fan with the rotation speed lowered.

A second effect of using the fluid medium of the examples is that a higher heat transfer effect can be obtained compared to the comparative examples.

The temperature of the upper heat transfer part of the combustion furnace was improved from 820 ° C. level as in Comparative Example 1 to 860 ° C. level by using the fluid medium of Example 1. have. That is, the increase in the temperature of the heat transfer portion increases the amount of movement of the fluid medium heated to a high temperature to the portion of the heat transfer surface, and as a result, a high heat transfer effect can be obtained.

A third effect of using the fluid medium of the embodiments is that fine dust can be reduced compared to the comparative examples.

In order to confirm this, using Examples 1 to 3 and Comparative Example 1, after the combustion furnace was operated for 30 hours, fly ash collected inside a bag filter was collected and its particle size distribution was measured, and the distribution amount of PM10 contained in fly ash was analyzed using a particle size analyzer (Malvern 2000MU model). The results for this are shown in FIGS. 5 to 8 .

5 is a comparison of Example 1 and Comparative Example 1 used as a fluid medium.

After the furnace was operated for 30 hours using the silica sand of Comparative Example 1 as a fluid medium, the average particle size of the collected fly ash was 20 μm, and the content of particles below PM10 was about 30%.

On the other hand, when the fluid medium of Example 1 is used, the average particle size of the generated fly ash is at the level of 70 μm, and the content of fine particles of PM10 or less is about 14 to 16%.

This is because most of the fine particles generated during the operation of the furnace are pulverized in a granular fluid medium (kaolin + bentonite + expanded pearl rock), etc. It means that they are agglomerated.

That is, as described above, the fluid medium of Example 1 lowers the compressive strength by 50% to reduce wear of equipment, and improves the specific surface area by about 40 times to improve reactivity with gaseous substances formed in the combustion furnace, It can be confirmed through FIG. 5 that the effect of improving the capture opportunity can be obtained. That is, it can be seen that the fluidized medium of Example 1 can replace the flowing sand and effectively collects and discharges fine dust, thereby reducing PM10 by about 50%.

6 is a comparison of Example 2 and Comparative Example 1 as a fluid medium under the same conditions.

As can be seen in FIG. 6 , when Example 2, which is a granular fluid medium granulated by combining (kaolin + coal fly ash + bentonite + expanded pearlite) as a fluid medium, is used, the average particle size of fly ash is about 70 ㎛ level, and the content of PM10 contained in the discharged fly ash is about 12%.

That is, it was possible to obtain a fine dust removal effect that was about 10% better than the result of Example 1 and a fine dust removal effect that was about 60% better than the result of Comparative Example 1.

This means that the collection power of fine dust can be improved by further including coal fly ash having excellent porosity in the combination of Example 1 used above.

7 is a comparison of Example 3 and Comparative Example 1 as a fluid medium under the same conditions.

As can be seen in FIG. 7 , when Example 3, which is a fluid medium granulated by combining (kaolin + zeolite + bentonite + expanded pearlite) as a fluid medium, is used, the average particle size of fly ash is about 160 μm. , the content of PM10 contained in the discharged fly ash was about 4 to 6%, indicating a more excellent effect of removing fine dust than Example 2.

These results show that the fine dust reduction effect is superior to the results of Examples 1 and 2, and in order to remove fine dust generated in a fluidized bed combustion furnace, a reactive aluminum silicate material such as kaolin and a material having excellent specific surface area are used in combination. You can confirm that using it works.

The results of Examples 1 to 3 are shown together in FIG. 8 .

Claims (7)

As a fluidized medium for a fluidized bed boiler that can replace fluidized sand,
The fluidized medium is for input to the combustion furnace of the fluidized bed boiler,
The fluid medium includes granular powders in which mixed powders of kaolin powder, expanded pearlite powder and bentonite powder are mixed,
30 parts by weight to 90 parts by weight of kaolin;
1 part by weight to 20 parts by weight of expanded pearlite; and
0.1 parts by weight to 10 parts by weight of bentonite;
including,
A granular fluid medium having an average particle diameter of 100 μm to 500 μm of the granular powder.
According to claim 1,
The granular fluid medium is
A granular fluid medium, characterized in that it further comprises 5 to 30 parts by weight of at least one material selected from the group consisting of coal fly ash and zeolite.
According to claim 1,
The granular fluid medium has a specific gravity of 1.0 to 1.8.
According to claim 1,
The granular fluid medium, characterized in that the compressive strength of the granular fluid medium is 10 kgf to 25 kgf.
mixing 30 parts by weight to 90 parts by weight of kaolin powder, 1 part by weight to 20 parts by weight of expanded pearlite powder, and 0.1 parts by weight to 10 parts by weight of bentonite powder; and
granulating and molding the mixed kaolin powder, expanded pearlite powder and bentonite powder to have an average particle diameter of 100 μm to 500 μm;
The method of claim 1, comprising a granular fluid medium.
The method of operating a fluidized bed combustion furnace, characterized in that 0.01 to 2.0 parts by weight of the granular fluid medium of claim 1 is used based on 100 parts by weight of fuel.
7. The method of claim 6,
The fluidized bed combustion furnace operating method, characterized in that the average particle size of the fly ash collected in the bag filter of the fluidized bed combustion furnace is 60 ㎛ or more.

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