TWI750196B - Acidic component remover, its manufacturing method and acidic component removal method - Google Patents

Abstract

The present invention provides an acidic component removing agent, which can suppress the increase in pressure loss for a wide variety of filter cloths used in bag filters, and can operate for a long time, and a method for producing the same and a method for removing acidic components using the same. An acid component remover, comprising sodium bicarbonate, colloidal calcium carbonate with a primary particle average particle diameter of 50 nm or less, and optional hydrophobic fumed silica; and in the acid component remover, the aforementioned colloidal calcium carbonate The content ratio is 0.05 to 5 mass %, and the content ratio of the hydrophobic fumed silica is less than 0.2 mass %.

Description

Acidic component remover, method for producing the same, and method for removing acidic component

The present invention relates to an acidic component removing agent for removing an acidic component in a gas, a method for producing the same, and a method for removing an acidic component in a gas using the acidic component removing agent.

The exhaust gas associated with the incineration of general waste and industrial waste contains acidic components such as hydrogen chloride and sulfur oxides. On the other hand, as an apparatus for removing acidic components in exhaust gas, a removal apparatus using an acidic component removing agent is known.

FIG. 1 is a schematic diagram of an example of an apparatus for removing acidic components in exhaust gas. The removal device shown in FIG. 1 is roughly composed of the following parts: a storage tower 1 for storing a powdery acid component removing agent M; an exhaust gas flow path (flue) 2 through which the exhaust gas containing acid components flows; The acid component removing agent is supplied from the storage tower 1 to the supply pipe 3 in the exhaust gas; and the bag filter 4 arranged on the downstream side of the exhaust gas flow path 2 .

The discharge part 1a of the storage tower 1 has a powder quantitative supply device 5 such as a rotary valve and a table-top feeder. And by operating the powder quantitative supply device 5 , the acidic component removing agent M is dropped to the opening 3 a of the supply pipe 3 . On the upstream side of the exhaust gas flow path 2, an incinerator (not shown) and the like for general waste, industrial waste, and the like are installed. In the exhaust gas flow path 2, exhaust gas containing acidic components such as hydrogen chloride, nitrogen oxides, and sulfur oxides from an incinerator or the like flows. The supply pipe 3 sends out the acidic component removing agent M supplied from the opening part 3a to the downstream side by the circulating air flow from the upstream side. The downstream end of the supply pipe 3 is arranged in the exhaust gas flow path 2 . And the downstream end of the supply pipe 3 is provided with an ejector 3b for ejecting the acidic component removing agent M into the exhaust gas.

The bag filter 4 is roughly composed of the following parts: a casing 41; an exhaust gas inlet 42 provided in a lower part 41a of the casing 41; a plurality of cylindrical filter cloths 43 arranged in a central part 41b of the casing 41; and The exhaust port 44 is provided in the upper part 41c of the casing 41 . The lower end of the filter cloth 43 is closed and the interior is formed as a hollow portion 43a. The upper part 41c and the central part 41b of the casing 41 are separated by the partition plate 45, and the exhaust gas must pass through the filter cloth 43 when the exhaust gas moves from the central part 41b of the casing 41 to the upper part 41c. A through portion 45 a is provided in the partition plate 45 , and a communication pipe 46 is installed in the through portion 45 a to communicate the hollow portion 43 a of the filter cloth with the upper portion 41 c of the housing 41 .

Next, the operation of the device for removing acidic components in exhaust gas will be described. The powder quantitative supply device 5 is activated, and the acidic component removing agent M in the storage tower 1 is supplied to the supply pipe 3 . The acidic component remover M supplied to the supply pipe 3 is conveyed by the airflow to the downstream end, and is ejected from the ejector 3b into the exhaust gas of the exhaust gas flow path 2 . A part of the ejected acidic component removing agent M reacts with the acidic component in the exhaust gas to become a reaction product. Then, the reaction product and the unreacted acidic component removing agent M are sent to the bag filter 4 together with the exhaust gas. In the bag filter 4, the reaction product and the unreacted acidic component removing agent M are deposited on the surface of the filter cloth 43 to form a filter layer, and the acidic component in the exhaust gas is further removed by the filter layer. The exhaust gas from which the acidic components have been removed passes through the filter cloth 43 and is discharged from the discharge port 44 through the communication pipe 46 .

The acid component remover used in the device for removing the acid component in the exhaust gas has been slaked lime (calcium hydroxide) in the past, but in recent years, it has been proposed that the main component is sodium bicarbonate, the average particle size is less than 50 μm, and The acid component remover of 10-30 micrometers is suitable (patent document 1).

In order to efficiently remove acidic components in exhaust gas, it is necessary to reduce the average particle diameter of the acidic component removing agent as much as possible. However, an acidic component remover with an average particle size of 30 μm or less may have poor fluidity, or the adhesion of particles to each other may increase and become easy to agglomerate, which may lead to difficulty in stable handling, and as a result, may lead to acidic components. Deterioration of removal efficiency.

That is, when the fluidity of the acidic component removing agent deteriorates and the adhesion between particles increases, the acidic component removing agent itself becomes easy to agglomerate. For example, as shown in FIG. 2 , a rat hole ( rat hole phenomenon, or as shown in FIG. 3 , a bridge phenomenon occurs in the storage tower 1 . As a result, the supply of the acidic component removing agent may be blocked, and the removal efficiency of the acidic component in the removing apparatus may be greatly reduced.

As an acid component remover system with improved fluidity, there is proposed an acid component remover in which fumed silica is added to sodium bicarbonate as an anti-caking agent (Patent Document 2). However, if the fluidity of the acidic component removing agent is extremely improved, the particles of the acidic component removing agent may easily penetrate into the fiber gaps of the filter cloth constituting the bag filter. Therefore, there are concerns that the following problems arise: the increase in pressure loss in the filter cloth greatly reduces the flow rate of the exhaust gas; the particles of the acid component removing agent leak through the filter cloth into the exhaust gas; and the particles accumulated on the surface of the filter cloth Excessive peeling of the filter layer. In addition, in order to restore the pressure loss of the filter cloth, the reverse flow of the compressed air from the reverse direction of the exhaust gas flow is carried out to blow off the particles of the acid component removing agent on the surface of the filter cloth and the gap between the fibers of the filter cloth (backwashing). Danger of irreversible recovery.

Each of the above-mentioned problems may involve a reduction in the removal efficiency of acidic components in the removal device. Therefore, in order to suppress the increase of the pressure loss of the filter cloth of the bag filter, the leakage of the acid component remover from the filter cloth, and the acid component remover that is detached from the filter layer deposited on the filter cloth surface, a method for producing the acid component remover has been proposed. , which is to mix sodium bicarbonate, hydrophobic fumed silica and colloidal calcium carbonate and then pulverize, or mix them at the same time; and, the average particle size of the primary particles of the aforementioned colloidal calcium carbonate is 50 nm or less, the content ratio of the hydrophobic fumed silica is 0.2 to 0.5 mass % in the acidic component remover, the content ratio of the colloidal calcium carbonate is 1.5 to 2.5 mass % in the acidic component removal agent, and the acid The average particle diameter of the component remover is 3 to 20 μm (Patent Document 3). Prior Art Documents Patent Documents

Patent Document 1: Japanese Patent Publication No. Hei 9-507654 Patent Document 2: Japanese Patent Laid-Open No. 2000-218128 Patent Document 3: International Publication No. 2012/036012

SUMMARY OF THE INVENTION Problems to be Solved by the Invention In the acid component removing agent of Patent Document 2 using a combination of hydrophobic fumed silica and colloidal calcium carbonate, the acid component removing agent is supplied from the temporarily stored storage tower to the exhaust gas. A certain improvement has been seen in supply instability, or in suppressing shedding of the filter layer. However, depending on the type of filter cloth, particles of the acid component remover may enter between the gaps of the fibers constituting the filter cloth, etc., and it becomes clear that the pressure loss caused by the filter cloth increases, and improvement is sought. .

An object of the present invention is to provide an acid component remover, a method for producing the acid component remover, and a method for removing an acid component from a gas using the acid component remover, wherein the acid component remover can be used for a bag filter The wide variety of filter cloths suppresses pressure loss and enables long-term operation. means of solving problems

The present invention includes the following aspects. [1] An acid component remover, characterized in that it contains sodium bicarbonate, colloidal calcium carbonate and optionally hydrophobic fumed silica, and has an average particle size of 3 to 20 μm; the primary particles of the aforementioned colloidal calcium carbonate The average particle size is 50 nm or less, and the content ratio of the colloidal calcium carbonate in the acid component remover is 0.05 to 5% by mass; and the content ratio of the hydrophobic fumed silica in the acid component remover is less than 0.2 mass % %. [2] The acidic component removing agent according to the above [1], wherein the colloidal calcium carbonate is not surface-treated, and the content ratio in the acidic component removing agent is 0.5 to 5 mass %. [3] The acidic component removing agent according to the aforementioned [1], wherein the colloidal calcium carbonate is surface-treated and the content ratio in the acidic component removing agent is 0.05 to 2 mass %. [4] The acidic component removing agent according to any one of the above [1] to [3], wherein the carbon content of the hydrophobic fumed silica is 0.8 to 5 mass %. [5] The acidic component removing agent according to any one of [1] to [4], wherein the content ratio of the hydrophobic fumed silica in the acidic component removing agent is less than 0.01 mass %. [6] The acidic component remover according to any one of the above [1] to [5], wherein the average particle diameter of the secondary particles of the colloidal calcium carbonate is 1 to 10 μm, which is smaller than the average particle diameter of the sodium bicarbonate. [7] The acidic component removing agent according to any one of the aforementioned [1] to [6], wherein the BET specific surface area of the aforementioned colloidal calcium carbonate is 30 m ² /g or more. [8] The acidic component removing agent according to any one of the above [1] to [7], wherein the breaking stress of the acidic component is 350 mN or less. [9] A method for producing an acidic component removing agent, which is a method for producing the acidic component removing agent according to any one of the aforementioned [1] to [8], characterized in that: sodium bicarbonate, colloidal calcium carbonate and optional The hydrophobic fumed silica contained is mixed and then pulverized by a pulverizing mechanism, or mixed and pulverized by a pulverizing mechanism. [10] The production method according to the aforementioned [9], wherein the sodium bicarbonate, colloidal calcium carbonate and optionally contained hydrophobic fumed silica are pulverized by the pulverizing mechanism, and then the pulverizing mechanism is used to pulverize the obtained pulverized silicon dioxide. things are graded. [11] The production method according to the above-mentioned [10], wherein the particles classified into the particle size exceeding 50 μm by the above-mentioned classification mechanism are returned to the above-mentioned pulverizing mechanism. [12] The production method according to any one of the aforementioned [9] to [11], wherein the pulverizing mechanism is an impact pulverizer or a jet mill. [13] A method for removing an acidic component from a gas, comprising temporarily storing the acidic component removing agent according to any one of the above [1] to [8] in a storage facility, and then supplying it to a gas containing an acidic component. [14] The method for removing an acidic component according to [13], wherein the acidic component removing agent according to any one of the above [1] to [8] is discharged from a storage facility, conveyed by an air flow, and supplied to a gas containing an acidic component . Invention effect

According to the acid component removing agent of the present invention, the acid component removing agent obtained by the production method of the present invention, and the acid component removing method in a gas using the acid component removing agent, it is possible to use the bag filter for a wide variety of filters. The cloth can restrain the pressure difference of the exhaust gas between the inlet and the outlet of the bag filter from rising, and can operate for a long time.

Forms for Carrying Out the Invention The terms used in this specification have the following meanings. "Differential pressure" refers to the pressure difference between the exhaust gas at the inlet and outlet of the bag filter. "Residual pressure loss" refers to the pressure loss after operating devices such as the acid component removal device and the dust collection performance test device for a certain period of time. "Backwashing" refers to the following operation: in order to restore the state of the filter cloth whose pressure loss has become high during the exhaust gas treatment, the compressed air is reversed from the direction of the exhaust gas flow to wipe off the surface of the filter cloth and the filter cloth. Particles of acid remover in fiber crevices. The "average particle size" is synonymous with the average particle size. The numerical range indicated by "~" means the range including the numerical values before and after the "~" as the lower limit value and the upper limit value.

<Acid component remover> The acid component remover of the present invention contains sodium bicarbonate, colloidal calcium carbonate and optionally hydrophobic fumed silica, and has an average particle size of 3 to 20 μm; 1 time of the aforementioned colloidal calcium carbonate The average particle size of the particles is 50 nm or less, and the content ratio of the colloidal calcium carbonate in the acid component remover is 0.05 to 5% by mass; and the content ratio of the hydrophobic fumed silica in the acid component remover is less than 0.2 quality%. In addition, the average particle diameter of the acidic component remover is the volume-based average particle diameter (MV) measured using a laser diffraction scattering particle size distribution analyzer (for example, Microtrac FRA9220 manufactured by Nikkiso Co., Ltd.). .

(Sodium Bicarbonate) The sodium bicarbonate used in the acidic component remover of the present invention can be used without limitation in terms of the average particle size of the sodium bicarbonate particles. The average particle diameter of the sodium bicarbonate particles means the average particle diameter of the entirety of the primary particles and the secondary particles. The average particle size of the sodium bicarbonate particles is preferably 50 μm or more, and preferably 90 to 300 μm.

Sodium bicarbonate is usually produced by crystallization in industry. In addition, when the average particle diameter is 50 μm or more, it can be obtained industrially efficiently by a crystallization method, and when it is used as an acid component remover, the fluidity in the storage tower becomes good and the handling is easy. In addition, when the average particle diameter is 300 μm or less, large energy is not required for pulverization. In addition, the average particle diameter of sodium bicarbonate particles is determined by a sonic vibration type sieving measuring device using a standard sieve (for example, an automatic dry sieving measuring device Robot Sifter RPS-105 manufactured by SEISHIN ENTERPRISE Co., Ltd.). The measured mass accumulation is the particle size (median diameter, D50) of 50% by mass.

(Colloidal calcium carbonate) The colloidal calcium carbonate contained in the acidic component remover of the present invention is chemically produced by a reactive crystallization method, etc., and is called a so-called colloidal calcium carbonate or a colloidal calcium carbonate. ) calcium carbonate precipitated calcium carbonate (synthetic calcium carbonate) is preferred. In this specification, the so-called colloidal calcium carbonate is used as a general term for those prepared without adding components for the purpose of surface treatment and those with surface treatment added with components for the purpose of surface treatment.

The primary particle average particle diameter of the colloidal calcium carbonate contained in the acidic component remover of this invention is 50 nm or less. When the average particle size is within the above-mentioned range, it is possible to manufacture stably and inexpensively industrially, and to obtain a powder that is easy to handle. The average particle size of the primary particles of the colloidal calcium carbonate produced by the reactive crystallization method is relatively small. When the colloidal calcium carbonate contained in the acidic component remover of the present invention is mixed with the pulverized sodium bicarbonate, it will adhere to the surface of the sodium bicarbonate particles, thereby reducing the adhesion of the sodium bicarbonate particles to each other. From this point of view, the average particle size is preferably smaller, and is preferably 1 to 50 nm, preferably 10 to 50 nm, and more preferably 10 to 30 nm. In addition, the average particle diameter of primary particles of colloidal calcium carbonate is measured by a scanning electron microscope (SEM). The values are obtained by arithmetic mean.

The average particle diameter of the secondary particles of the colloidal calcium carbonate in the present invention means the particle diameter of the aggregated particles due to the Van der Waals force acting between the primary particles. The average particle size of the secondary particles of the colloidal calcium carbonate should preferably be smaller than the average particle size of the sodium bicarbonate, so that it can be easily attached to the surface of the sodium bicarbonate particles. The average particle size of the secondary particles of the colloidal calcium carbonate is preferably 1 to 10 μm. When the average particle diameter of the secondary particles of colloidal calcium carbonate is 1 μm or more, the cohesiveness does not become too high, and the particles are difficult to adhere to each other. Therefore, when it is used as an acid component remover, it is easy to stably discharge from the storage tower. When it is 10 μm or less, it is easy to disperse uniformly during the pulverization operation. From the viewpoint of cohesiveness, it is preferably 1 to 5 μm. The average particle diameter of the secondary particles of the colloidal calcium carbonate is the volume-based average particle diameter (MV) measured by a laser diffraction scattering measuring device.

According to the BET specific surface area of the obtained colloidal calcium carbonate measured by the nitrogen adsorption method, from the viewpoint of obtaining powder that is easy to handle, it is preferably 30 m ² /g or more, preferably 40 m ² /g or more. The colloidal calcium carbonate can be either the colloidal calcium carbonate that has not been surface-treated on the particle surface, or the colloidal calcium carbonate that has been surface-treated on the particle surface (hereinafter referred to as surface-treated colloidal calcium carbonate). The surface-treated colloidal calcium carbonate suppresses the agglomeration of its particles and disperses easily and uniformly. The surface-treated colloidal calcium carbonate is preferably a surface treatment to which resin acids or fatty acids such as abietic acid and lignin are attached to the surface of the colloidal calcium carbonate particles. The average particle diameters of the primary particles and the secondary particles of the surface-treated colloidal calcium carbonate and the BET specific surface area measured by the nitrogen adsorption method are the same as the aforementioned colloidal calcium carbonate, and the ideal form is also the same. The surface-treated colloidal calcium carbonate can be suitably used commercially available items. For example, NCC series (product name of Nitto Powder Chemical Industry Co., Ltd.), Bai Yanhua series manufactured by Shiraishi Industry Co., Ltd., Calmos, and Vigot series (product name of SHIRAISHI CALCIUM KAISHA, LTD.) are mentioned. Commercially available ones can be suitably used for the colloidal calcium carbonate without surface treatment. For example, NEOLIGHT VT (product name of Takehara Chemical Industry Co., Ltd.) and KARURAITO-KT (product name of Shiraishi Industry Co., Ltd.) are mentioned.

The content ratio of the colloidal calcium carbonate in the acidic component remover is 0.05 to 5 mass %. When it is 0.05 mass % or less, it becomes difficult to stabilize the dischargeability from the storage tower, and when it is 5 mass % or more, problems such as clogging of the filter cloth are likely to occur. When the colloidal calcium carbonate is not surface-treated, the content ratio of the colloidal calcium carbonate in the acidic component remover is preferably 0.5 to 5 mass %. If it is 0.5 mass % or more, the dischargeability from the storage tower will be easily improved sufficiently, and if it is 5 mass % or less, problems such as clogging of the filter cloth will hardly occur. The content ratio is preferably 1 to 4 mass %, more preferably 2 to 3 mass %.

When the colloidal calcium carbonate has been surface-treated, the content ratio of the surface-treated colloidal calcium carbonate in the acidic component remover is preferably 0.05 to 2 mass %. As long as the content ratio is 0.05 mass % or more, stable discharge from the storage tower is easy, and when it is 2 mass % or less, the acidic component removing agent becomes difficult to fall off from the filter cloth, and it becomes easy to sufficiently form a filter layer on the filter cloth. . The content ratio is preferably 0.1 to 1.5 mass %, more preferably 0.1 to 1.2 mass %, and particularly preferably 0.2 to 1.0 mass %.

(Hydrophobic fumed silica) The content ratio of the hydrophobic fumed silica contained in the acidic component removing agent of the present invention is less than 0.2 mass % with respect to 100 mass % of the acidic component removing agent. Hydrophobic fumed silica refers to the surface of fumed silica that has been hydrophobized, which is different from general fumed silica whose surface has not been hydrophobicized. As the fumed silica, among the synthetic amorphous silicas, those produced by a dry method are preferred. Specifically, those produced by a combustion method, a self-ignition method, or a heating method can be mentioned.

Examples of the hydrophobization treatment include: silane treatment with dimethyldichlorosilane, hexamethyldisilazane, octylsilane, etc.; silane coupling agent treatment with vinyltrimethoxysilane; Polysiloxane treatment, methyl hydrogen polysiloxane treatment, fatty acid treatment, etc. The so-called degree of hydrophobicity of hydrophobic fumed silica is an index showing the degree of adhesion of hydrophobic treatment agents such as dimethylsilane attached to the surface of fumed silica, and the degree of hydrophobic fumed silica is represented by carbon content. The carbon content of the hydrophobic fumed silica is determined by a combustion type carbon content measuring device (SUMIGRAPH NC-80 (manufactured by Sumika Chemical Analysis Service, Ltd.) or EMIA-110 (manufactured by HORIBA, Ltd.), etc.). Determination.

The carbon content of the hydrophobic fumed silica is preferably 0.8 to 5% by mass. When the carbon content is 0.8 mass % or more, the fluidization effect can be sufficiently obtained. If it is 5 mass % or less, the cohesion of the hydrophobic fumed silica does not become too strong, and it is easy to disperse. As the hydrophobic fumed silica, commercially available ones can be suitably used.

Among the acidic component removers, it is preferable that the hydrophobic fumed silica is mostly uniformly dispersed on the surface of sodium bicarbonate particles in the state of primary particles. In this case, compared with the case where the hydrophobic fumed silica exists in the state of secondary particles, it is easier to make the fluidity of the acidic component remover appropriate, and it is easier to suppress lumps due to aggregation. change. Therefore, the average particle size of the primary particles of the hydrophobic fumed silica is preferably 5 to 50 nm. When the average particle diameter is 5 nm or more, the cohesiveness does not become too strong, and it is easy to disperse in the acidic component removing agent. When the average particle diameter of the primary particles of the hydrophobic fumed silica is 50 nm or less, the predetermined effect can be easily obtained. From the viewpoint of improving the fluidity, it is preferably 5 to 40 nm. In addition, the so-called primary particle of hydrophobic fumed silica refers to the smallest unit of the constituent particle determined by visual observation of the SEM observation image. The average particle size of primary particles of hydrophobic fumed silica is measured by SEM. Specifically, the particle size of 100 primary particles is measured from the SEM image of each particle, and the measured values are arithmetically averaged. And the winner.

The content ratio of the hydrophobic fumed silica in the acidic component remover is less than 0.2 mass %. If the content ratio is less than 0.2 mass %, the particles in the acidic component remover will not slip excessively, and the filter cloth will not be easily clogged. In order to reduce the amount of dust discharged after exhaust gas treatment, dissolution treatment is sometimes performed under acidic conditions. At this time, if the hydrophobic fumed silica gel becomes difficult to handle, from the viewpoint of suppressing this, the content of the hydrophobic fumed silica is preferably as small as possible. The content ratio is preferably less than 0.16 mass %, preferably less than 0.1 mass %, more preferably less than 0.01 mass %. It may also be free of hydrophobic fumed silica.

When the colloidal calcium carbonate in the acid component remover is not surface-treated, it is preferable to use hydrophobic fumed silica from the viewpoint of adjusting the fluidity of the particles. When the colloidal calcium carbonate has been subjected to surface treatment, from the viewpoint of adjusting the fluidity of the particles, the content of the hydrophobic fumed silica is preferably as small as possible.

(The fumed silica not subjected to the hydrophobization treatment) The acidic component remover of the present invention may contain the fumed silica not subjected to the hydrophobization treatment. The fumed silica without hydrophobization treatment is preferably produced by a dry method in the synthesis of amorphous silica. The dry method includes a combustion method, a self-ignition method, a heating method, and the like.

The average particle size of the primary particles of the fumed silica without hydrophobization treatment is preferably 5-50 nm. As long as the average particle diameter is 5 nm or more, the cohesiveness does not become too strong, and it is easy to disperse in the acidic component removing agent. As long as the average particle diameter is 50 nm or less, a predetermined effect can be easily obtained. From the viewpoint of better fluidity, 5 to 40 nm is preferable. The so-called primary particles of fumed silica that have not been hydrophobized refer to the smallest unit of the constituent particles determined by visual observation of the SEM image. The average particle size of primary particles of fumed silica is measured by SEM. Specifically, it is obtained by measuring the particle size of 100 primary particles from the SEM image of each particle, and arithmetically averaging the measured values. By.

To make the acid component remover into a desired fluidity and obtain a powder that is easy to handle, the physical properties can be adjusted with hydrophobic fumed silica and fumed silica that has not been hydrophobized. The fumed silica that has not been hydrophobized tends to improve the adhesion of particles to each other. Therefore, it is difficult for the filter cloth to increase the pressure loss due to the acidic component remover. Moreover, the acidic component removing agent is suppressed from falling off from the filter cloth surface, and it is easy to hold|maintain well. Hydrophobic fumed silica tends to increase the fluidity of acid removers. Therefore, it is difficult to form rat holes or bridges in the storage tower, and it can be easily discharged from the storage tower or the feeder.

When the colloidal calcium carbonate in the acid component remover is not subjected to surface treatment, it is preferable to not contain fumed silica that is not subjected to hydrophobization treatment from the viewpoint of improving the fluidity of the particles. When the colloidal calcium carbonate in the acid component remover has been surface-treated, it may contain fumed silica that has not been hydrophobized from the viewpoint of adjusting the fluidity of the particles. When the fumed silica that has not been hydrophobized is contained, the content ratio of the fumed silica in the acid component remover is preferably 0.01 to 5% by mass, and from the viewpoint of adjusting particle fluidity, it is preferably 0.05 ~3 mass %.

(Other components) As components that can be contained in the acidic component removing agent of the present invention, in addition to the above-mentioned ones, acidic component removing components such as potassium bicarbonate, slaked lime, and zeolite, adsorbents such as activated carbon, and the like can be exemplified. Silicon dioxide powder, basic magnesium carbonate, calcium carbonate and diatomaceous earth and other anti-caking agents. In the acid component remover, excluding other components, the rest is preferably sodium bicarbonate. The total content ratio of sodium bicarbonate, colloidal calcium carbonate and hydrophobic fumed silica in the acidic component remover is preferably 85% by mass or more, preferably 90% by mass or more, and more preferably 95% by mass or more.

The average particle size of the acidic component remover is 3 to 20 μm. As long as the average particle diameter is 3 μm or more, sufficient fluidity can be obtained, and it is difficult to cause the problem that the particle diameter is too small to pass through the filter cloth. As long as it is 20 μm or less, the acidic components in the exhaust gas can be easily and efficiently removed. When the average particle diameter is less than 3 μm, the fluidity is poor and there is a problem of passing through the filter cloth. If it exceeds 20 micrometers, the removal efficiency of the acidic component in exhaust gas will be inferior. In order to easily and efficiently remove acidic components, it is preferably 5 to 10 μm.

<Production method of acid component remover> The acid component remover of the present invention can be produced by a method of mixing sodium bicarbonate, colloidal calcium carbonate and optionally contained hydrophobic fumed silica and then pulverizing it, or It is a method of mixing at the same time during pulverization. Since it is preferable for these powders to coexist during most of the time of pulverization, it is advisable to mix these powders and then supply the mixture to the pulverizer. .

If the particle size of sodium bicarbonate is small, the adhesion of the particles to each other becomes large, and it is easy to form agglomerates. In addition, the fluidity of the powder deteriorates and it becomes difficult to handle. Therefore, if sodium bicarbonate is separately pulverized, and then colloidal calcium carbonate and hydrophobic fumed silica as an optional component are mixed, it may be difficult to uniformly mix. According to the aforementioned manufacturing method, the colloidal calcium carbonate and the hydrophobic fumed silica belonging to the optional components can be uniformly distributed on the surface of the sodium bicarbonate.

The obtained acidic component remover is preferably composed of particles having a structure in which fine particles of colloidal calcium carbonate and hydrophobic fumed silica as optional components are attached to the surface of the particles of pulverized sodium bicarbonate. In the process, the particles of the acid component remover are generated by the following matters: sodium bicarbonate, colloidal calcium carbonate and hydrophobic fumed silica belonging to optional components are pulverized into primary particles or secondary particles, and colloids are generated. Primary particles and secondary particles of calcium carbonate and hydrophobic fumed silica which are optional ingredients adhere to the surface of the pulverized sodium bicarbonate particles. It is preferable that the acidic component remover in this invention consists of the aggregate of the said particle|grains.

The acidic component remover of the present invention can be used to crush sodium bicarbonate, colloidal calcium carbonate and optionally contained hydrophobic fumed silica with a crushing mechanism, and then use a classification mechanism to classify the crushed product obtained by crushing. It can also be produced by returning the particles classified by the above-mentioned classification mechanism to the particle size exceeding 50 μm to the above-mentioned pulverization mechanism. The above-mentioned particles with a particle size exceeding 50 μm are classified by a classification mechanism and then returned to the crushing mechanism for repeated crushing, whereby an acid component remover with an average particle size of 3-20 μm can be prepared. The pulverizing mechanism is preferably an impact pulverizer (a pulverizer using high-speed rotating blades, etc.), a jet mill (a pulverizer using a collision airflow) and a ball mill. In order to obtain fine particles, it is preferable to use an impact pulverizer or a jet mill. Although the cost of power required for a jet mill will be high, it is particularly desirable because it is suitable for micronization.

Although the classification mechanism can be used without particular limitation, a wind type classifier is preferable. The crushing mechanism and the grading mechanism may be independent devices, respectively, and may also be a device in which the crushing mechanism and the grading mechanism are integrated. An example of an apparatus in which a pulverizing mechanism and a classifying mechanism are integrated is an impact-type pulverizer including a pneumatic classifier. When using an impact-type pulverizer equipped with an air classifier, the pulverized material discharged from the pulverizer is continuously classified according to the particle size and sent back to the pulverizing mechanism, so productivity can be improved. In the acidic component remover, when other components are contained, it is also possible to manufacture in the same manner as described above, and the ideal form thereof is also the same.

<Method for removing acid component in gas> The method for removing acid component in gas using the acid component remover of the present invention is preferably as follows: after temporarily storing the acid component remover in a storage facility, it is then supplied to the gas containing acid component. method. Preferably, the acidic component removing agent temporarily stored in the storage facility is discharged from the storage facility, and the acidic component removing agent conveyed by the airflow is supplied to the gas containing the acidic component by conveying it with an air flow. The storage device may be a storage tower. As a method of discharging the acidic component remover from a storage device, for example, a method using a rotary valve or a quantitative conveying table, which is generally used, is exemplified. The air flow that conveys and supplies the acid component removing agent discharged from the storage facility to the acid component-containing gas may be an air flow. As for the gas containing acidic components, for example, the exhaust gas discharged from the incineration treatment of general waste (municipal waste), the boiler and the manufacturing process of various products.

As acid components, for example, hydrogen chloride, hydrogen fluoride, sulfur oxides (sulfur dioxide) contained in the exhaust gas from incinerators such as general waste, industrial waste, and medical waste; Sulfur oxides (sulfur dioxide, sulfur trioxide, sulfuric acid), nitrogen oxides; and substances that show acidity in the exhaust gas mixed in the manufacturing process of various products. The temperature of the gas containing acid components should be higher than the dew point of these acid components. In the case of the exhaust gas from the incinerators of general waste, industrial waste, and medical waste, from the viewpoint of suppressing the generation of dioxins, a relatively low temperature is preferred, specifically, 100 to 200°C. In addition, from the viewpoint of efficiently removing the acidic component, the temperature is preferably 150 to 200° C. in order to prevent the acidic component from coagulating. When using a filter cloth carrying a catalyst capable of decomposing dioxins as the filter cloth of the bag filter described later, or when using a device with a catalyst capable of reducing dioxins or nitrogen oxides, it may be 200. ~250℃.

As a dispersing mechanism for dispersing the acidic component removing agent in the gas, a device for removing the acidic component in the exhaust gas as shown in FIG. 1 may be used. In this device, since the filter layer of the acid component removing agent is formed on the filter cloth surface of the bag filter, the acid component can be efficiently removed. As the filter cloth of the bag filter, various materials can be used. For example, synthetic fibers, glass fibers, carbon fibers, and fluororesins may be mentioned. Synthetic fibers include, for example, polypropylene, acrylic, polyester, polyphenylene sulfide, polyimide, and polyaramide. The fluororesin includes, for example, polytetrafluoroethylene (hereinafter referred to as PTFE) and polyvinylidene fluoride. These fibers may be used alone or in combination of two or more. The material of the filter cloth is preferably synthetic fiber, glass fiber or fluororesin, preferably glass fiber or fluororesin.

In terms of the form of the filter cloth, it can be a woven cloth, a non-woven cloth, a porous film, a woven cloth with a porous film, a nonwoven cloth with a porous film, a nonwoven cloth with a mesh-like surface, and the like. In order to impart acid resistance and antistatic properties to improve the ability to remove acidic components in the exhaust gas, the surface of the filter can also be treated with catalysts and antistatic agents. On the other hand, in the case of fragile materials such as glass fibers, the surface may be subjected to lamination treatment in order to impart strength. As the filter cloth, glass fiber double-layer fabric filter cloth, glass fiber double-layer fabric filter cloth with lamination treatment on the surface and non-woven filter cloth with PTFE can be suitable.

Compared with the glass fiber double-layer fabric filter cloth, the differential pressure of the glass fiber double-layer fabric filter cloth with lamination treatment on the surface is easier to rise, and the PTFE non-woven cloth filter cloth is prone to the occurrence of acid component remover particles. The tendency of the filter cloth surface to fall off, etc. As far as the acid component remover of the present invention is concerned, even the glass fiber double-layered fabric filter cloth or the PTFE non-woven filter cloth with the laminated treatment on the surface can still make it show good performance.

When the exhaust gas treatment is performed by supplying the acid component removing agent, the by-product salts produced are discharged from the bottom of the exhaust gas introduction port 42 shown in FIG. 1 . Although the by-product salt may be directly disposed of by landfill, in some cases, one or more water-insoluble inorganic salts other than alkali metal chlorides are dissolved with acids such as hydrochloric acid, nitric acid, and organic acid, and then filtered. Decrease operation. When the acid component remover contains excessively fumed silica, the acid will cause the fumed silica to gel, and the filtration efficiency will be easily reduced. When the content of fumed silica in the acid component remover is low or not contained, it is difficult to reduce the filtration efficiency.

<Characteristics of Acid Component Remover> The fracture stress of the acid component remover is an indicator of the caking and caving easiness of the acid component remover in storage equipment such as storage towers. The breaking stress is preferably smaller. And it is preferably 350 mN or less, preferably 300 mN or less, more preferably 250 mN or less. As long as the breaking stress is 350 mN or less, the filter layer deposited on the surface of the filter cloth is less likely to fall off, and when the filter cloth is backwashed, the filter layer can be easily removed from the filter cloth. In addition, it becomes difficult to form rat holes or bridging phenomenon in storage equipment such as storage towers, and the acidic component remover can be stably discharged.

The fracture stress of the acid component remover can be obtained by measuring by the bisection groove method using a suspension powder layer adhesion measuring device (manufactured by Hosokawa Micron Corporation, Kohi Tester DT-2 type). The residual pressure loss in the filter cloth and the leakage concentration of the acid component remover from the filter cloth and the operating time can be determined according to the German Industrial Standard (Deutsche Industrie Norm) formulated by CIN (German Institute for Standardization). ) of the dust collection performance test device (Filter MeCiaTester) and the device based on JIS Z8909-1 (Test method for dust collection filter cloth) formulated in 2007, or the measurement performed by these devices as a reference.

The residual pressure loss in the filter cloth when using the acid component remover is the value obtained according to the residual pressure loss test method described later. Although it also depends on the type of filter cloth, it is better to be 100Pa or less. As long as the residual pressure loss is 100Pa or less, the degree of penetration of the particles of the acidic component remover into the fiber gaps of the filter cloth constituting the bag filter is small, and the bag filter can operate stably for a long time.

In addition, it will be clarified in the residual pressure loss test described later that the longer the better operating time, the better. And in the case of considering the actual operation, even if the residual pressure loss of the filter cloth is high, it is better to have a longer operating time. The operable time is preferably 30 hours or more, preferably 35 hours or more.

The leakage concentration of the acidic component remover from the filter cloth is preferably 15 mg/Nm ³ or less, more preferably 5 mg/Nm ³ or less. As long as the leakage concentration of the acid component remover from the filter cloth is 15 mg/Nm ³ or less, the burden on the living environment caused by the discharged dust can be suppressed.

The acidic component remover of the present invention can suppress the increase in pressure loss for a wide variety of filter cloths used in bag filters, and can operate for a long time. According to the present invention, the acidic component removing agent can be produced, and the acidic component in the gas can be removed using the acidic component removing agent. Example

Embodiments are disclosed below, but the present invention is not limited to these embodiments for explanation.

<Shearing test> A shearing test using an annular shearing groove (Jenike Cell, inner diameter: 64 mm, stainless steel SUS316) was carried out, and the adhesion, wall friction angle, inclination angle of the feeding funnel, and out diameter.

(Adhesion) The vertical load (W) and shear load (W1~W3) used for the test are determined according to the overall specific gravity of the test powder as shown in Table 1. After the lower fixed shear tank was filled with the test powder, a vertical load was applied to the upper cover of the shear tank for pre-compression, and the compression was performed while maintaining the same vertical load until the shear force became a stable value. Then, according to Table 1, the shear stress was measured while applying the shear load. The failure envelope is obtained by plotting the shear stress relative to the shear load, and the adhesion force is obtained from the intercept of the failure envelope. Adhesion is an indicator of the adhesion of powders to each other, and the smaller one is better.

[Table 1]

(Wall friction angle) The vertical load (W) and shear load (W1~W4) used for the test are determined according to the overall specific gravity of the test powder as shown in Table 2. After the test powder has been filled in the lower fixed shear groove, a vertical load is applied to the upper cover of the shear groove whose bottom material is stainless steel SUS316 for pre-compression. In accordance with Table 2, the shear stress was measured while applying the shear load. The wall failure envelope was obtained by plotting the shear stress with respect to the shear load, and the wall friction angle with stainless steel SUS316 was obtained from the slope of the wall failure envelope. The wall friction angle is an indicator of the mutual adhesion between the powder and the container, and the smaller one is better.

[Table 2]

(Inclination angle of addition funnel) Using the wall friction angle calculated from the measured value, the inclination angle of the addition funnel was obtained from the ff contour line. It shows that the larger the inclination angle of the feeding funnel is, the particles will still flow even if the angle of the feeding funnel is moderated. The angle of inclination of the addition funnel refers to the angle α shown in FIG. 4 . The dotted line X shown in FIG. 4 is a vertical line. That is, the inclination angle of the feeding funnel refers to the inclination of the bottom surface of the storage tower required for the powder to be stably discharged from the storage tower, and the larger one is the powder that is easier to handle.

(Outlet diameter) Taking the vertical load during the adhesion test as grade 1, the same test is also carried out for grades 2 to 4 in Table 3, and the respective failure envelopes are obtained. The maximum principal stress and unrestrained failure stress of each grade were read from these plot points, and a straight line FF was obtained as a function of powder flow. And fD (unconstrained failure stress) was obtained from the intersection of the FF and the straight line ff obtained according to the wall friction angle and the inclination angle of the feeding funnel. The caliber is further obtained from the sub-form. The outlet function here is a function determined by the inclination angle of the feeding funnel and the shape of the feeding funnel. The outlet diameter refers to the diameter of the outlet of the storage tower required for the stable discharge of the powder from the storage tower, and the smaller one is better. Outlet diameter [Dm]=fD×outlet function ÷ volume density of powder used

[table 3]

<Fracture Stress Test> A fracture stress test using a suspension powder layer adhesion measuring device (manufactured by Hosokawa Micron Corporation, Kohi Tester DT-2 type) was carried out, and the fracture stress was determined as follows.

Fill about 20g of the sample into a two-part tank formed by splicing 2 cylinders (inner diameter: 50mm, height: 20mm), and press the pre-compression load: 480Pa, temperature: 20 ℃, relative humidity: 50% The powder layer was obtained by pressing under ambient pressure for 2 hours to perform compression. One of the cylindrical parts of the tank was stretched at a speed of 1 mm/min in the direction perpendicular to the cylinder axis, and shear stress was applied to the powder layer at the position where the two cylinders were joined to measure the powder layer cracking. Breaking stress at break.

<Residual pressure loss test and operating time> The residual pressure loss and operating time were obtained in the following manner using a dust collection performance test device based on JIS Z8909-1 (Test method for filter cloth for dust collection). Under the conditions of a filtration area of 0.0139 m ² , a filtration rate of 2.0 m/min, and a dust concentration of 5.0 g/m ³ , the operation was performed until the differential pressure of the filter was 1000 Pa. Then, under the conditions of pulse pressure of 0.5MPa and pulse operation time of 50ms, the filter cleaning performed by pulse was performed to blow off the dust collected on the filter. In the above-mentioned method, the operation was continued until the filter cleaning performed by the pulse was performed for 15 times, after which the supply of dust was stopped and the operation was stopped. The pressure loss was measured after performing the filter cleaning performed by 10 pulses under the same conditions as above, and it was regarded as the residual pressure loss. And under the aforementioned conditions, the time required for dust collection on the filter to be swept off 15 times after the start of the test until the dust supply was stopped was defined as the operating time.

<Leakage Concentration> The leakage concentration from the filter cloth was calculated from the amount of medicine and the amount of gas passing through the absolute filter installed in the latter stage of the test filter in the residual pressure loss test described above. The filters used in the test are as follows. X: Glass fiber double-layer fabric filter cloth. Y: Glass fiber double-layer fabric filter cloth with laminated surface treatment. Z: PTFE non-woven filter cloth. The ingredients used in the test are as follows. A: Sodium bicarbonate (average particle diameter: 95 μm). B: colloidal calcium carbonate (average particle diameter of primary particles: 20 nm, average particle diameter of secondary particles: 1 to 10 μm, BET specific surface area: 49 m ² /g). C: Surface-treated colloidal calcium carbonate (primary particle average particle diameter: 20 nm, secondary particle average particle diameter: 1 to 10 μm, BET specific surface area: 49 m ² /g, fatty acid additive). D: Hydrophobic fumed silica (primary particle average particle diameter: 20 nm, carbon content: 1 mass %).

[Examples 1 to 10] (Manufacture of acid component remover) After mixing so that the content ratios of the components A, B, C, and D described above become the ratios shown in Table 4, they were pulverized by an impact type equipped with an air classifier. Pulverizer (ADM PULVERIZER ADM-10A, manufactured by Hosokawa Micron Corporation) classifies the pulverized material discharged from the pulverizer, and the particles exceeding 50 μm are returned to the pulverizer for pulverization, thereby obtaining acidity with an average particle size of 9 μm. ingredient removers and compared. In addition, Examples 3 to 6 and 8 to 10 are examples, and Examples 1, 2 and 7 are comparative examples.

Table 4 shows the result of carrying out the said test with respect to the obtained acidic component remover. Since the leakage concentration is zero in all examples, the records in the table are omitted.

[Table 4]

Examples 1 and 2 of the acidic component removing agent contain 0.2 mass % or more of the acidic component removing agent of hydrophobic fumed silica. For example 1 and 2, there is a large difference in performance according to the type of filter cloth, and neither filter cloth can take into account the good residual pressure loss and operating time.

(Supply from Storage Facility and Removal of Acid Component) The acid component remover obtained in Example 5 was temporarily stored in a storage tower provided with a ventilation nozzle (M Technique Co., Ltd.) as a countermeasure against powder fluidization system, Fluidizer), and discharged on a quantitative conveying table. And when supplied to the hydrogen chloride-containing exhaust gas flowing through the process shown in FIG. 1, the acidic component removing agent is stably discharged from the storage tower, and the hydrogen chloride has been removed. Also, none of the problems in the bag filter occurred. industrial availability

The acid component remover produced by the production method of the present invention is used to remove, for example, hydrogen chloride and sulfur dioxide in the exhaust gas from waste incinerators; sulfur dioxide, sulfur trioxide and sulfuric acid in the exhaust gas from boilers; and other various gases The acidic components in it are useful. In addition, the entire contents of the specification, scope of application, drawings, and abstract of Japanese Patent Application No. 2016-137445 filed on July 12, 2016 are incorporated herein by reference and incorporated into the disclosure of the specification of the present invention.

1‧‧‧Storage tower 1a‧‧‧exhaust part 2‧‧‧exhaust gas flow path (flue) 3‧‧‧supply pipe 3a‧‧‧opening part 3b‧‧‧ejector 4‧‧‧bag filter 41‧ ‧‧Case 41a‧‧‧Lower part 41b‧‧‧Central part 41c‧‧‧Upper part 42‧‧‧Introduction port for exhaust gas 43‧‧‧Filter cloth 43a‧‧‧Hollow part 44‧‧‧Exhaust port 45‧ ‧‧Partition plate 45a‧‧‧Through part 46‧‧‧Connecting pipe 5‧‧‧Powder quantitative supply device M‧‧‧Acid component remover α‧‧‧Inclination angle of feeding funnel

FIG. 1 is a schematic diagram of an example of a removal apparatus for removing acid components in exhaust gas using an acid component remover. FIG. 2 is a schematic diagram illustrating the rat-hole phenomenon in the storage tower of the removal device of FIG. 1 . FIG. 3 is a schematic diagram illustrating the bridging phenomenon in the storage tower of the removal device of FIG. 1 . FIG. 4 is a schematic diagram illustrating the inclination angle of the addition funnel in the storage tower of the removal device of FIG. 1 .

1‧‧‧Storage tower

1a‧‧‧Discharge part

2‧‧‧Exhaust gas flow path (flue)

3‧‧‧Supply Pipe

3a‧‧‧Opening

3b‧‧‧Ejector

4‧‧‧bag filter

41‧‧‧Shell

41a‧‧‧Lower

41b‧‧‧Central

41c‧‧‧Top

42‧‧‧Introduction port for exhaust gas

43‧‧‧Filter cloth

43a‧‧‧Hollow part

44‧‧‧Exhaust port

45‧‧‧Partition

45a‧‧‧Through part

5‧‧‧Powder quantitative supply device

46‧‧‧Connecting pipe

M‧‧‧Acid component remover

Claims (14)

An acid component remover, characterized in that: the acid component remover is only composed of sodium bicarbonate and colloidal calcium carbonate without surface treatment, and the average particle size is 3-20 μm; the aforementioned surface treatment is a resin acid or fatty acid. Adhesion surface treatment; the primary particle average particle size of the colloidal calcium carbonate is 50 nm or less, and the content ratio of the colloidal calcium carbonate in the acid component remover is 2.5 to 3 mass %. An acid component remover, characterized in that: the acid component remover is only composed of sodium bicarbonate and colloidal calcium carbonate that has undergone surface treatment, and the average particle size is 3 to 20 μm; the aforementioned surface treatment is a resin acid or fatty acid. Adhesion surface treatment; the primary particle average particle diameter of the aforementioned colloidal calcium carbonate is 50 nm or less, and the content ratio in the acidic component remover is 0.3 to 0.8 mass %. The acidic component remover according to claim 1 or 2, wherein the average particle size of the secondary particles of the colloidal calcium carbonate is 1-10 μm, and is smaller than the average particle size of the sodium bicarbonate. The acidic component remover according to claim 1 or 2, wherein the BET specific surface area of the aforementioned colloidal calcium carbonate is 30 m ² /g or more. The acid component removing agent according to claim 1 or 2, wherein the breaking stress of the acid component removing agent is 350 mN or less. A manufacturing method of an acid component remover, which is to manufacture The method for removing an acidic component according to any one of Claims 1 to 5, wherein sodium bicarbonate and colloidal calcium carbonate are mixed and then pulverized by a pulverizing mechanism, or mixed and pulverized by a pulverizing mechanism. According to the production method of claim 6, after the sodium bicarbonate and the colloidal calcium carbonate are pulverized by the pulverizing mechanism, the pulverized product obtained by the pulverization is classified by the classification mechanism. The production method of claim 7, wherein the particles classified by the classifying mechanism and having a particle size exceeding 50 μm are returned to the pulverizing mechanism. The manufacturing method according to any one of claims 6 to 8, wherein the pulverizing mechanism is an impact pulverizer or a jet mill. A method for removing acid components in gas, which comprises temporarily storing the acid component removing agent according to any one of claims 1 to 5 in a storage facility, and then supplying it to a gas containing acid components. The acid component removal method of claim 10, wherein the acid component remover according to any one of claims 1 to 5 is discharged from a storage facility, conveyed by an air flow, and supplied to a gas containing an acid component. The method for removing acidic components according to claim 10 or 11, wherein the acid component removing agent according to any one of claims 1 to 5 is discharged from a storage device, conveyed by an air flow, and supplied to a gas containing acid components, and then bagged in a bag The filter filters the reaction product of the acid component remover and the acid component and the unreacted acid component remover; and the filter cloth of the bag filter is a glass fiber double-layer fabric filter cloth or PTFE non-woven cloth whose surface has been subjected to lamination treatment filter cloth. A method for removing acidic components, which is to remove the acidic components The remover is discharged from the storage equipment and conveyed by air flow to be supplied to the gas containing the acid component, and then the reaction product of the acid component remover and the acid component and the unreacted acid component remover and the unreacted acid component remover are filtered with a bag filter; wherein the bag filter The filter cloth of the filter is a glass fiber double-layer fabric filter cloth or a PTFE non-woven cloth filter cloth whose surface has been subjected to lamination treatment; the aforementioned acid component remover is only composed of sodium bicarbonate and colloidal calcium carbonate without surface treatment, and the average particle size is 3~20μm; the aforementioned surface treatment is a surface treatment for attaching resin acid or fatty acid; the average particle size of the primary particles of the aforementioned colloidal calcium carbonate is 50 nm or less, and the content ratio of the colloidal calcium carbonate in the acid component remover is 2.5 ~3 mass %. A method for removing an acidic component, comprising: discharging an acidic component removing agent from a storage device, conveying it with an air flow, and supplying it to a gas containing an acidic component, and filtering the reaction product and unreacted acid component between the acidic component removing agent and the acidic component with a bag filter The aforementioned acid component remover; wherein the filter cloth of the aforementioned bag filter is a glass fiber double-layer fabric filter cloth or a PTFE non-woven filter cloth whose surface has been subjected to lamination treatment; the aforementioned acid component remover is only composed of sodium bicarbonate and surface-treated It is composed of colloidal calcium carbonate and has an average particle size of 3 to 20 μm; the aforementioned surface treatment is a surface treatment for attaching resin acid or fatty acid; the average particle size of the primary particles of the aforementioned colloidal calcium carbonate is 50 nm or less, and the colloidal calcium carbonate is The content ratio in the acid component remover is: 0.3 to 0.8 mass %.

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