KR102124792B1 - Acid gas treatment agent - Google Patents

Abstract

It is possible to efficiently treat the acid gas even in a small amount, and to significantly improve the high pressure and differential pressure increase in the bag filter, and also provides an excellent acid gas treatment agent in terms of cost. The acidic gas treating agent of the present invention contains sodium hydrogen carbonate. The median diameter of sodium hydrogen carbonate (D ₅₀ ) is 11 μm or more and 25 μm or less, and the ratio of the mode diameter (D _m ) to median diameter (D _m /D ₅₀ ) is 2.0 or less. The difference between the median diameter (D ₅₀ ) and the accumulated weight 30% diameter (D ₃₀ ) is preferably 15 μm or less, and the difference between the integrated weight 70% diameter (D ₇₀ ) and the median diameter (D ₅₀ ) is 15 μm or less. desirable.

Description

Acid gas treatment agent

The present invention relates to an acid gas treatment agent. More specifically, the present invention is an acid for neutralizing acid gases such as hydrogen chloride or sulfur oxides contained in combustion exhaust gas discharged from a facility for incineration, firing or melting of general waste or industrial waste, or a biomass power generation boiler. It relates to a gas treatment agent.

Acid gas such as hydrogen chloride or sulfur oxides is generated in waste treatment facilities or power boilers, and calcium-based compounds such as slaked lime have been used to neutralize the acid gas.

However, when JIS special slaked lime or high-reacted slaked lime is used as the acid gas treatment agent, it is necessary to use it in excess of 3 to 4 times the equivalent of acid gas. This has the drawback of increasing or squeezing the capacity of the final disposition. In addition, there are some drawbacks that cannot be stably treated in a facility where the sulfur oxide is particularly high, but in a facility where the level of hydrogen chloride and sulfur oxide is 15 mm or less and the wet level is strict.

Therefore, sodium-based compounds such as sodium hydrogen carbonate are also commonly used and widely used as acid gas treatment agents. Sodium hydrogen carbonate is finished in a small amount compared to the slaked lime.

For example, Patent Document 1 proposes an acidic component remover containing sodium hydrogen carbonate having an average particle diameter of 1 to 9 μm on a volume basis measured by laser diffraction scattering. According to this remover, acidic components such as hydrogen chloride, sulfur oxides, and nitrogen oxides can be efficiently removed from the exhaust gas, and disposal is easy and the amount of waste can be reduced.

In Patent Document 2, the average particle diameter based on volume measured by the laser diffraction scattering method is 1 to 9 µm, and in the pore distribution by the mercury intrusion method of the powder layer, the pore volume in the range of pore diameters 1 to 10 µm is 0.4 cm. An acidic component remover containing more than ³ / ³ sodium hydrogen carbonate has been proposed. According to this remover, hydrogen chloride gas can be sufficiently adsorbed and removed with a small amount of acidic component remover.

Japanese Unexamined Patent Publication No. 2000-218128 Japanese Patent Application Publication No. 2006-239689

All of the treatment agents described in Patent Documents 1 to 2 are said to preferably have an average particle diameter of sodium hydrogen carbonate of 10 μm or less. However, when sodium hydrogen carbonate is a fine particle, the fine particles are easily agglomerated and coagulated, but there is a problem that the pulverization cost and the pulverization time for making the fine particle are enormous.

In order to prevent agglomeration between the fine particles, an anti-caking agent may be added to sodium hydrogen carbonate, but even if an anti-caking agent is added to sodium hydrogen carbonate, the acid gas treatment agent may sometimes congeal during transport or storage of the drug. In addition, if the mixing ratio of the anti-caking agent is increased, a problem of cost increase occurs this time.

In addition, when the average particle diameter of sodium hydrogen carbonate is small, a differential pressure in a bag filter for purifying exhaust gas rises, which causes a problem in durability of the filter cloth.

The present invention has been made in consideration of such a problem, and the problem is that even in a small amount, the acid gas can be efficiently processed, and also the stiffness and the differential pressure increase in the bag filter can be significantly improved, and the acidity is excellent in terms of cost. It is to provide a gas treatment agent.

As a result of repeated studies of the inventors in order to achieve the above-mentioned problems, the present inventors focused on the ratio (D _m /D ₅₀ ) of the mode diameter (D _m ) to the median diameter, and by making the range of this ratio within a certain range It has been found that the above problems can be solved all at once and the present invention has been completed. Specifically, the present invention provides the following.

(1) In the present invention, the median diameter (D ₅₀ ) is 11 μm or more and 25 μm or less, and the ratio of the mode diameter (D _m ) to the median diameter (D _m /D ₅₀ ) is 2.0 or less acidic sodium hydroxide. It is a gas treatment agent. Here, the median diameter (D ₅₀ ) is a particle diameter in which the integrated value in the mass standard is 50% in the particle size distribution measured by the laser diffraction scattering particle size distribution measuring device. In addition, the mode diameter (D _m ) is a particle diameter in which the relative particle amount in the particle size distribution measured by the laser diffraction scattering type particle size distribution measuring device becomes the maximum.

(2) In addition, the present invention, the difference between the median diameter (D ₅₀ ) and the accumulated weight of 30% diameter (D ₃₀ ) of the sodium hydrogen carbonate is 15 μm or less, and 70% of the accumulated weight of the sodium hydrogen carbonate diameter (D) ₇₀ ) and the median diameter (D ₅₀ ) is the acidic gas treatment agent described in (1), wherein the difference is 15 μm or less. Here, the integrated weight 30% diameter (D ₃₀ ) is a particle diameter in which the integrated value in the mass standard is 30% in the particle size distribution measured by the laser diffraction scattering particle size distribution measuring device. In addition, the integrated weight 70% diameter (D ₇₀ ) is a particle diameter in which the integrated value in the mass standard is 70% in the particle size distribution measured by the laser diffraction scattering particle size distribution measuring device.

(3) In addition, the present invention further contains an anti-caking agent, and the anti-caking agent is the acid described in (1) or (2) comprising at least one or more selected from hydrophilic materials, hydrophobic materials, and clay minerals. It is a gas treatment agent.

(4) The present invention is also described in (3), wherein the anti-caking agent includes any one or more of wet silica, calcium stearate, zeolite, hydrophobic silica, hydrophilic fumed silica, white carbon, basic magnesium carbonate, and carbon black. It is an acid gas treatment agent.

(5) In addition, the present invention is an acid gas treatment method for collecting fly ash after adding the acid gas treating agent according to any one of (1) to (4) to the acid gas.

ADVANTAGE OF THE INVENTION According to this invention, even if it is a small amount, it can process an acidic gas efficiently, and can also improve the pressure increase in a high-integrity property or a bag filter drastically, and can provide the acidic gas treating agent excellent in cost.

1 shows a schematic configuration of an acid gas processing apparatus 10 used in this embodiment.
2 shows a schematic configuration of a load testing device 30 used to evaluate the integrity of the acid gas treatment agent.

Hereinafter, specific embodiments of the present invention will be described in detail, but the present invention is not limited to the following examples and can be carried out by appropriately changing within the scope of the object of the present invention.

<Acid gas treatment agent>

The acidic gas treating agent of this embodiment contains sodium hydrogen carbonate. Sodium hydrogen carbonate functions as a neutralizing agent for acid gas.

Moreover, it is preferable that an acidic gas treatment agent further contains an anti-caking agent as needed.

[Sodium hydrogen carbonate]

[Median diameter (D ₅₀ )]

As for sodium hydrogen carbonate, a crude crushed crude sodium bicarbonate is preferably used. The lower limit of the median diameter (D ₅₀ ) of sodium hydrogen carbonate is 11 μm or more, preferably 12.5 μm or more, more preferably 15 μm or more, and particularly preferably 17 μm or more. If the median diameter (D ₅₀ ) is too small, it is not preferable since the fine particles of sodium hydrogen carbonate are easily aggregated and solidified. In addition, it is not preferable because the grinding cost or the grinding time for making sodium hydrogen carbonate as fine particles increases. Moreover, if the median diameter (D ₅₀ ) is too small, it is not preferable because the differential pressure in the bag filter for purifying the exhaust gas rises and may affect the durability of the filter cloth.

The upper limit of the median diameter (D ₅₀ ) of sodium hydrogen carbonate is 25 μm or less, preferably 21 μm or less, and more preferably 19.5 μm or less. If the median diameter (D ₅₀ ) is too large, the amount of sodium hydrogen carbonate necessary to treat the acid gas is outside the range of the equivalent equivalent ratio to the concentration of the acid gas at the inlet of the bag filter (for example, 1.0 or more and 5.0 or less). It is not desirable.

[Ratio of mode diameter (D _m ) to median diameter (D ₅₀ ) (D _m /D ₅₀ )]

The ratio of the mode diameter (D _m ) to the median diameter (D ₅₀ ) of sodium hydrogen carbonate (D _m /D ₅₀ ) is 2.0 or less, preferably 1.5 or less, and more preferably 1.3 or less. When the ratio (D _m /D ₅₀ ) is large, the acid gas cannot be sufficiently treated even when the median diameter (D ₅₀ ) is within an appropriate range.

Although the lower limit of the ratio (D _m /D ₅₀ ) is not particularly limited, the lower limit of the ratio (D _m /D ₅₀ ) is 1.00 or more because the mode diameter (D _m ) is larger than the median diameter (D ₅₀ ). .

[Sharpness of particle size distribution]

The upper limit of the difference (D ₅₀ -D ₃₀ ) between the median diameter (D ₅₀ ) of sodium hydrogen carbonate and the 30% diameter (D ₃₀ ) of the accumulated weight is preferably 15 μm or less, and more preferably 10 μm or less. The lower limit of the difference (D ₅₀ -D ₃₀ ) is not particularly limited, and may be greater than 0 μm, but in order to increase the product yield and provide an excellent acid gas treatment agent in terms of cost, the lower limit of the difference (D ₅₀ -D ₃₀ ) Silver is preferably 1 μm or more, and more preferably 3 μm or more.

The upper limit of the difference (D ₇₀ -D ₅₀ ) between the accumulated weight of sodium hydrogen carbonate 70% in diameter (D ₇₀ ) and the median diameter (D ₅₀ ) is preferably 15 μm or less, and more preferably 10 μm or less. The lower limit of the tea (D ₇₀ -D ₅₀ ) is not particularly limited, and may be greater than 0 μm, but in order to increase the product yield and provide an excellent acid gas treatment agent in terms of cost, the lower limit of the tea (D ₇₀ -D ₅₀ ) is It is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more.

Due to the sharp particle size distribution, the processing performance of acid gas is increased. In addition, due to the sharp particle size distribution, condensation of the acidic gas treatment agent can be suppressed, and as a result, the handling performance of the device is enhanced.

〔Anti-caking agent〕

In order to prevent the acidic gas treating agent from solidifying and lowering fluidity, the acidic gas treating agent preferably contains sodium hydrogen carbonate and an anticaking agent.

The anti-caking agent preferably contains at least one selected from hydrophilic materials, hydrophobic materials and clay minerals.

In the present embodiment, the term "hydrophilic" refers to a material that is insoluble in water but has a hydrophilic group on the material surface, so that the material surface is easily wetted by water (does not produce water droplets and does not splash). As a hydrophilic substance, hydrophilic silica (hydrophilic fumed silica, etc.) is mentioned.

In the present embodiment, "hydrophobic" refers to a substance that is insoluble in water and does not have a hydrophilic group on the substance surface. Examples of the hydrophobic substance include calcium stearate and hydrophobic silica.

Examples of clay minerals include zeolite, diatomaceous earth, and activated clay.

Especially, since it is excellent in anti-caking property, it is preferable that a caking-preventing agent contains calcium stearate.

In addition, white carbon, basic magnesium carbonate, carbon black, calcium carbonate, magnesium carbonate, magnesium hydroxide, ammonium citrate, anhydrous magnesium sulfate, anhydrous sodium phosphate, blast furnace slag, aluminum oxide, etc. An antioxidant may be included.

When the anti-caking agent is contained, the lower limit of the content is not particularly limited as long as the acid gas treating agent can consolidate and prevent the fluidity from falling. For example, the content of the anti-caking agent is preferably 0.1 parts by mass or more, and more preferably 0.2 parts by mass or more with respect to 100 parts by mass of sodium hydrogen carbonate.

The upper limit of the content is not particularly limited as long as it does not affect the treatment of the desalting residue. For example, the content of the anti-caking agent is preferably 3.0 parts by mass or less, more preferably 1.0 parts by mass or less, more preferably 0.8 parts by mass or less, and even more preferably 0.6 parts by mass or less with respect to 100 parts by mass of sodium hydrogen carbonate. desirable.

<Preparation method of acid gas treatment agent>

The preparation of the acid gas treatment agent can be obtained through the following steps.

(1) Grinding of heavy tanks (heavy tanks with large particle size)

(2) Mixing of crushed sodium bicarbonate (sodium hydrogen carbonate) and anti-caking agent as necessary.

((1) Crusher of Crude Tank)

First, the crude tank is crushed, and the ratio (D _m /D ₅₀ ) of the mode diameter (D _m ) to the median diameter (D ₅₀ ) and the median diameter (D ₅₀ ) is adjusted within the range of the regulation. The median diameter (D ₅₀ ) and the like are adjusted by adjusting the set values of the pulverizing rotor and the classifying rotor in the pulverizer based on the particle size of the raw material of the crude tank and the amount of raw material supplied by the crude tank.

((2) Mixing of crushed sodium bicarbonate (sodium hydrogen carbonate) with anti-caking agent]

Also, if necessary, crushed sodium bicarbonate (sodium hydrogen carbonate) and an anti-caking agent are mixed. The mixing may be performed using a mixer such as a ribbon blender or a nauta mixer, or when a crude tank is crushed, an anti-caking agent may be added together with the crude tank to mix.

<Acid gas treatment method>

In the treatment of the acid gas, the acid gas treatment agent is added to the exhaust gas containing the acid gas to perform the exhaust gas treatment. It is made by supplying the acid gas treatment agent to flue, and contacting the acid gas treatment agent with the exhaust gas containing the acid gas.

The type of exhaust gas is not particularly limited, and includes, for example, exhaust gas generated from waste treatment facilities, combustion facilities such as biomass boilers, coal boilers, and acid gases such as hydrogen chloride or sulfur oxides. have.

The timing for supplying the acid gas treatment agent is not particularly limited as long as the dust collector is before collecting the fly ash, for example, the timing of incineration of waste and the like in the incinerator, and exhaust gas generated by incineration passes through the flue and exhausts. The timing between the temperature of the gas to the temperature reduction tower and the timing of the exhaust gas after cooling in the temperature reduction tower until the exhaust gas after cooling reaches the bag filter installed in front of the dust collector. have.

The supply amount of the acid gas treatment agent is not particularly limited. In order to avoid both undersizing and oversizing, it is desirable to supply appropriately adjusted concentrations while monitoring the concentration of acid gas passing through the flue to satisfy the target management targets for each combustion facility.

In order to properly process the acid gas, the supply amount of the lower limit of the acid gas treatment agent is more preferably not less than 0.1g / m ³ or more is preferable and, 1g / m ³ or more is more preferable, and, 10g / m ^3. In addition, the lower limit of the supply amount of the acid gas treatment agent is preferably 1.0 or more, more preferably 1.2 or more, and even more preferably 1.4 or more in an equivalent ratio to the concentration of the acid gas at the inlet of the bag filter.

In order to suppress the amount of desalination residues and to make the cost of scattering ash as low as possible, the upper limit of the supply amount of the acid gas treatment agent is preferably in the range of 200 g/m ³ or less, and more preferably in the range of 150 g/m ³ or less desirable. In addition, the upper limit of the supply amount of the acid gas treatment agent is preferably 5.0 or less, more preferably 3.0 or less, and even more preferably 2.0 or less, in an equivalent ratio to the concentration of the acid gas at the inlet of the bag filter.

After supplying the acidic gas treatment agent to the flue, a scattering material containing reaction products and unreacted substances between the acidic gas and the acidic gas treatment agent is collected. The dust collecting of the fly ash may be performed using a known dust collector such as a bag filter.

[Example]

Hereinafter, the present invention will be specifically described by examples, but the present invention is not limited to these.

<Example 1> Relationship between particle size of sodium hydrogen carbonate and acidic gas treatment performance and solidity

(Comparison of acid gas treatment performance)

[Exam conditions]

The acidic gas treatment performance of six types of sodium hydrogen carbonate listed in Table 1 was compared using the acidic gas treatment apparatus 10 shown in FIG. In addition, the diameter of sodium hydrogen carbonate was measured using the SLD-7500 nano from Shimadzu Corporation (SHIMADZU CORPORATION).

1 shows a schematic configuration of an acid gas processing apparatus 10 used in this embodiment. The acid gas processing apparatus 10 includes a heater 11 for heating acid gas, an acid gas treatment agent supply 13 for supplying an acid gas treatment agent to the acid gas from the heater 11, and an acid gas and acid gas treatment agent. A bag filter (15) for collecting reaction products and unreacted substances with, a cooling tower (17) for cooling the collected dust collected by the bag filter (15), and a neutralization tower (18) for neutralizing the cooled dust collection, The neutralization tower 18 is provided with an incentive blower 19 for discharging the neutralized neutralized material to the outside of the system.

In the pipe 12 from the heater 11 to the acid gas treatment agent supply 13, a pressure gauge P1 and a hydrogen chloride concentration measuring device are provided at a place corresponding to the inlet of the bag filter 15. The inlet pressure of the bag filter 15 and the hydrogen chloride concentration contained in the acidic gas can be measured by the pressure gauge P1 and the hydrogen chloride concentration measuring device.

In addition, in the pipe 16 from the bag filter 15 to the cooling tower 17, a pressure gauge P2 and a hydrogen chloride concentration measuring device are provided at a place corresponding to the outlet of the bag filter 15. The pressure gauge P2, the outlet pressure of the bag filter 15 and the concentration of hydrogen chloride contained in the dust collected by the bag filter 15 can be measured by the hydrogen chloride concentration measuring device.

In addition, in this embodiment, as an apparatus for measuring hydrogen chloride, Kyoto Electron Manufacturing Co., Ltd. product "ion electrode type hydrogen chloride system L-22" was used.

The test conditions in Example 1 are as follows.

Exhaust gas volume: 0.28Nm ³ -dr y/myn

Hydrogen chloride concentration at the inlet of the bag filter 15: 250 mm (407 mg/Nm ³ )

Moisture content: 10%

Bag filter temperature: 170℃

Addition amount of acid gas treatment agent: 1.5 equivalent to the inlet hydrogen chloride concentration

Addition time of acid gas treatment agent: 90 minutes by continuous addition

[evaluation]

The removal rate of hydrogen chloride when the acidic gas treating agent was continuously added for 90 minutes was calculated according to the following formula. When the removal rate of hydrogen chloride was 85% or more, it was set to "○", and when it was less than 85%, it was set to "X". Table 1 shows the results.

Acid gas removal rate (%) = (Hydrogen chloride concentration at the inlet-Hydrogen chloride concentration at the outlet) / Hydrogen chloride concentration at the inlet × 100

(Acidity of acid gas treatment agent)

Using the load test apparatus 30 shown in FIG. 2, evaluation of high integrity was performed with the following contents.

The load test apparatus 30 is provided with a frame 32 of 100 mm x 100 mm, and a weight 32 of 10 kg weighted to a sample (acid gas treatment agent) accommodated in the frame 31.

First, various acid gas treating agents S according to Examples and Comparative Examples are filled in a frame shape of 100 mm×100 mm. Then, a load of 10 kg was applied to the acid gas treatment agent (S) using a weight 32 for 18 hours.

After that, using a sieve apparatus having a first body having an eye size of 710 μm and a second body having an eye size of 350 μm, the acid gas treatment agent S is vibrated in the order of the first body and the second body. The weight remaining on the sieve of the first sieve and the sieve of the second sieve was measured by dropping, and the ratio of the sieve residue to the weight of the acid gas treating agent (S) provided in the test (unit: wt%) was calculated. The smaller the proportion of the residual, the smaller the acidity of the acid gas treatment agent, and the ratio of the sieve residue was used as an index to evaluate the solidity of each acid gas treatment agent. , &Quot;○&quot; for more than 20% and 50% or less, &quot;△&quot; for 50% or more and 90% or less, and &quot;×&quot; for more than 90%. .

〔result〕

All sodium hydrogen carbonates having a median diameter (D ₅₀ ) of 11 μm or more and 25 μm or less, and a mode diameter (D _m ) to median diameter (D _m /D ₅₀ ) of 2.0 or less, all had high acid gas treatment performance. (Examples 1-1 to 1-3). From the excellent acid gas treatment performance, it is also expected to reduce the environmental load, such as extending the final disposal by reducing the amount of soot dust and reducing the COD of leachate.

In addition, the sodium hydrogen carbonate also has excellent anti-caking properties (Examples 1-1 to 1-3). Among them, if the median diameter (D ₅₀ ) is 15 μm or more, it is more excellent in anti-caking properties (Examples 1-2 and 1-3), and more than 17 μm, it is more excellent in anti-caking properties (Example 1-3). .

In addition, since the median diameter (D ₅₀ ) of sodium hydrogen carbonate is not micronized to less than 11 μm, it also leads to a reduction in manufacturing cost. Moreover, it is also possible to shorten the grinding time of the tank and increase the amount of grinding, so that the acidic gas treatment agent can be stably supplied.

On the other hand, it was confirmed that if the median diameter (D ₅₀ ) is less than 11 μm, the acidic gas treatment agent tends to solidify and can affect the handling properties of the device (Comparative Example 1-1).

Further, even if the median diameter (D ₅₀ ) is within the range of 11 μm or more and 25 μm or less, if the ratio of the mode diameter (D _m ) to the median diameter (D _m /D ₅₀ ) exceeds 2.0, sufficient acid gas treatment performance cannot be obtained. It was confirmed (Comparative Examples 1-2, 1-3).

<Example 2> Comparison of anti-caking agent

(Acidity of acid gas treatment agent)

With respect to 100% by weight of sodium hydrogen carbonate having a particle size shown in Table 2, the anti-caking agent described in Table 2 was mixed at the ratio shown in Table 2 to obtain various acid gas treating agents. Then, the integrity of the acid gas treatment agent was evaluated in the same manner as in Example 1. Table 2 shows the results.

〔Differential pressure test in bag filter〕

The acidic gas processing apparatus 10 shown in Fig. 1 was operated under the following test conditions. The pressure loss of the bag filter was determined from the difference between the pressure measured by the pressure gauge P1 and the pressure measured by the pressure gauge P2.

Gas flow rate: 0.43m ³ /ｍｉｎ

Filtration area of bag filter (15): 0.43m ²

Filtration speed of the bag filter (15): 1m/ml

Dust collection temperature of the bag filter (15): 170℃

Addition amount of acid gas treatment agent: 116g/m ³

Pressure setting: 0.5 Pa (When the pressure loss of the bag filter reaches 0.5 Pa, it is automatically backwashed.)

Test time: 60 minutes

[evaluation]

During the continuous addition of the acid gas treatment agent for 60 minutes, the pressure loss of the bag filter reached 0.5 Pa and the number of times the automatic backwashing was performed was counted. It shows that the peeling property from the bag filter of an acidic gas treatment agent becomes good, so that the pressure loss of a bag filter can be prevented from increasing, so that this number of times is small. Table 2 shows the results.

〔result〕

When the anti-caking agent is not added to the sodium hydrogen carbonate having a median diameter (D ₅₀ ) of 11 μm or more and 25 μm or less, and the ratio (D _m /D ₅₀ ) of the mode diameter (D _m ) to median diameter of 2.0 or less is not added. Compared with, anti-corrosion property is more excellent (Examples 2-2 to 2-5, 2-12 to 2-15, 2-22 to 2-25). Among them, if the anti-caking agent contains calcium stearate, it has particularly excellent anti-caking properties (Examples 2-4, 2-5, 2-14, 2-15, 2-24, 2-25).

Sodium hydrogen carbonate having a median diameter (D ₅₀ ) of 11 μm or more and 25 μm or less, and a ratio of the mode diameter (D _m ) to median diameter (D _m /D ₅₀ ) of 2.0 or less, is a bag filter regardless of the type of anti-caking agent. It was confirmed that the number of times that the backwashing of the pressure reached 0.5 MPa and became automatic backwashing was excellent and the peelability from the bag filter was excellent in the acidic gas treatment agent, thereby preventing an increase in the pressure loss of the bag filter (Example) 2-1 to 2-5, 2-11 to 2-15, 2-21 to 2-25). This is considered to be because sodium hydrogen carbonate particles or particles of an anti-caking agent can be prevented from being inserted into the filter cloth, and a stable filter layer is formed on the surface of the filter cloth.

Among them, if the median diameter (D ₅₀ ) is 17 μm or more, the increase in the pressure loss of the bag filter can be prevented more effectively (Examples 2-21 to 2-25).

On the other hand, if the median diameter (D ₅₀ ) is less than 11 μm, an increase in the pressure loss of the bag filter cannot be sufficiently suppressed (Comparative Examples 2-1 to 2-5, 2-11 to 2-15). This is considered to be because the sodium hydrogen carbonate particles or particles of the anti-caking agent were inserted inside the filter cloth.

10 Acid gas treatment device
11 heater
13 Acid gas supply
15 Bag Filter
17 Cooling tower
18 Chinese Tower
19 Manned blower
P1, P2 pressure gauge

Claims (5)

An acidic gas treatment agent containing sodium hydrogen carbonate and anti-caking agent having a median diameter (D ₅₀ ) of 11 μm or more and 25 μm or less, and a ratio (D _m /D ₅₀ ) of the mode diameter (D _m ) to the median diameter of 2.0 or less, The anti-caking agent is an acid gas treatment agent consisting of calcium stearate.
According to claim 1,
The difference between the median diameter (D ₅₀ ) and the accumulated weight 30% diameter (D ₃₀ ) of the sodium hydrogen carbonate is 15 μm or less,
An acidic gas treating agent having a difference between the accumulated weight of 70% of the sodium hydrogen carbonate diameter (D ₇₀ ) and the median diameter (D ₅₀ ) of 15 μm or less.
A method for treating acidic gas by adding the acidic gas treating agent of claim 1 or 2 to an acidic gas and then collecting fly ash. delete delete

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