JP6521299B2 - Halide absorber - Google Patents

Description

  The present invention relates to halide absorbers.

  In recent years, effective use of resources and reduction of wastes are required, and it is considered that raw material gas produced from biomass and wastes will be used as fuel gas for power generation equipment (fuel cells, gas turbines, gas engines, etc.) ing. Since the raw material gas produced from biomass and waste contains halides such as hydrogen chloride and hydrogen fluoride as highly corrosive impurities, the fuel gas for fuel cells, gas turbines, gas engines and other power generation equipment It is necessary to remove impurities in advance to use as

  A dry impurity removal system utilizing a chemical reaction with an alkaline solid substance is considered as a technology for removing halides in gas, and it has been conventionally practiced to use an absorbent containing sodium aluminate. Since sodium aluminate is inherently water-soluble and has a deliquescent property that absorbs moisture in the air and liquefies even in a dried solid state, it is originally a material that is difficult to mold, so heat is applied. It is manufactured by synthesizing sodium aluminate by firing at a high temperature using a raw material for producing sodium aluminate in the process of sintering, for example, a mixture of sodium carbonate and alumina sol as a raw material (for example, Patent Document 1) ).

  Pore distribution is known to greatly affect the removal performance as an absorbent for removing halides. That is, since absorption of the halide causes a volume change in the absorbent, when the pores consist only of pores having a size of, for example, 0.1 μm or less, the small pores may be combined with the halide such as hydrogen chloride. There is a risk that the volume change caused by the reaction of sodium aluminate may cause clogging and the removal performance of the halide to deteriorate.

  An absorbent prepared by synthesizing sodium aluminate using a mixture of sodium carbonate and alumina sol as a raw material has high initial performance because carbon dioxide is released during sintering to form very fine pores, but the pores have high performance. The above-mentioned pore blockage may occur and unreacted sodium aluminate may remain inside the absorbent because it is not taken into consideration for the distribution of sodium chloride, leaving room to improve the performance of the halide absorbent. Was the current technology.

Patent No. 3571219 gazette

  The present invention has been made in view of the above situation, and it is an object of the present invention to provide a halide absorbent capable of suppressing a reduction in the absorption performance of the halide even if the halide is absorbed to cause a volume change. .

The halide absorbent of the present invention according to claim 1 for achieving the above object is a porous halide absorbent containing sodium aluminate capable of removing a halide, having a plurality of pore sizes. The peak having a large amount of pores is present, and the peak having a large amount of pores has a first peak at a pore diameter of 2 μm to 20 μm and a peak of 0.1 μm to 1.0 μm. And a second peak at the pore diameter between them. That is, the present invention is characterized in that it is a porous body having a so-called multiple pore distribution in which the distribution of pore amounts has a peak at a plurality of pore diameters.

  In the present invention according to claim 1, since there is a peak in which the amount of pores increases with a plurality of pore diameters, the halide is absorbed to cause a volume change (expansion / contraction) to cause relatively small pores. Even if the clogged, the relatively large pores do not impede the flow of gas. For this reason, even if a volume change occurs during the reaction of a halide such as hydrogen chloride and sodium aluminate, it is possible to suppress a decrease in the absorption performance of the halide.

  The pore diameter of the peak where the amount of pores increases is preferably about 1 μm in between, and is preferably set to a value different by about one digit.

And, the halide absorbent of the present invention according to claim 2 is a porous halide absorbent containing sodium aluminate capable of removing a halide, and has a plurality of pore sizes and a pore amount of The peak having a large number of peaks is present, and the peak having a large amount of pores has a first peak at a pore size of between 2 μm and 20 μm and a pore size of between 0.02 μm and 1.8 μm. And the second peak of the

In the present invention according to claim 2, since there is a peak in which the amount of pores increases with a plurality of pore diameters, the halide is absorbed to cause a volume change (expansion / contraction), resulting in relatively small pores. Even if the clogged, the relatively large pores do not impede the flow of gas. For this reason, even if a volume change occurs during the reaction of a halide such as hydrogen chloride and sodium aluminate, it is possible to suppress a decrease in the absorption performance of the halide.

The halide absorbent of the present invention according to claim 3 is the halide absorbent according to claim 2 , wherein the second peak has a pore diameter of 0.3 μm to 1.8 μm. It features.

In the present invention according to claims 1 to 3 , the degree of absorption of halide (absorption rate) is defined by defining two peaks in the primary and secondary ranges for the diameter of the peak at which the amount of pores increases. And the volume change condition, and the inside of the halide absorbent can be effectively absorbed without the flow resistance of the gas containing the halide becoming too high.

The halide absorber of the present invention according to claim 4 is a porous halide absorber containing sodium aluminate capable of removing a halide, and has a plurality of pore sizes and a pore amount of The peak having a large number of peaks is present, and the peak having a large amount of pores has a first peak at a pore size of between 2 μm and 20 μm and a pore size of between 0.3 μm and 1.8 μm. And a third peak at a pore diameter of between 0.02 μm and 0.2 μm.

In the present invention according to claim 4 , the absorption degree (absorption rate) and volume of the halide are defined by defining three peaks in the primary, secondary and tertiary ranges for the diameter of the peak at which the amount of pores increases. The state of change can be finely balanced, and the inside of the halide absorbent can be effectively absorbed without the flow resistance of the gas containing the halide becoming too high.

In the halide absorbent of the present invention according to claim 5 , in the halide absorbent according to any one of claims 1 to 3 , a powder of sodium aluminate, a molding aid, and pore formation It is characterized in that the agent is formed as a raw material.

In the present invention according to the fifth aspect , the porous sodium aluminate powder, the forming auxiliary agent, and the pore forming agent are mixed, kneaded, formed, and fired to form pores at the site of the organic auxiliary agent, It is possible to obtain a halide absorbent in which there is a peak where the amount of pores increases with a plurality of pore sizes.

In the halide absorbent of the present invention according to claim 6 , in the halide absorbent according to claim 4 , a powder of sodium aluminate, a plurality of types of molding assistants, and a pore-forming agent are used as raw materials. It is characterized in that it is molded.

In the present invention according to claim 6 , the powder of sodium aluminate at low cost, and a plurality of types of forming aids and pore forming agents are mixed, kneaded, formed, and fired at the site of the organic aid It is possible to obtain a halide absorbent which is porous and has a peak in which the amount of pores increases with a plurality of pore sizes.

  For this reason, it becomes possible to manufacture a halide absorber, without reducing the absorption capability of a halide by making it porous using the powder of cheap sodium aluminate.

  And, a strength enhancing additive can be contained, and a halide absorbent reinforced with the strength enhancing additive can be obtained. As a result, there is no damage even if an impact is applied at the time of filling the container into pellets or granules. For example, glass fiber is applied as a strength reinforcing additive.

  The halide absorbing agent of the present invention can suppress the decrease in the absorbing ability of the halide even if the volume of the halide is absorbed to cause a volume change.

It is a conceptual diagram explaining the process for manufacturing the halide absorber which concerns on 1st Example of this invention. It is a graph explaining the pore distribution of the halide absorbent concerning a 1st example of the present invention. It is a schematic diagram of the pore structure of the halide absorber which concerns on 1st Example of this invention. It is a table figure explaining evaluation conditions. It is a graph showing the time-dependent change of the exit concentration of the halide (HCl) by the halide absorbent concerning a 1st example of the present invention. It is explanatory drawing explaining the composition before and behind use of the halide absorber which concerns on 1st Example of this invention. It is a conceptual diagram explaining the process for manufacturing the halide absorber which concerns on 2nd Example of this invention. It is a graph explaining the pore distribution of the halide absorbent concerning a 2nd example of the present invention. It is explanatory drawing explaining the composition before and behind use of the halide absorber which concerns on 2nd Example of this invention. It is a graph explaining the pore distribution of the halide absorber of a comparative example. It is a schematic diagram of the pore structure of the halide absorber of a comparative example. It is a graph showing the time-dependent change of the exit concentration of the halide (HCl) by the halide absorber of a comparative example. It is explanatory drawing explaining the composition before and behind use of the halide absorber of a comparative example.

  The halide absorbent of the present invention contains sodium aluminate which can remove the halide by kneading and molding the powder of sodium aluminate, a molding aid and a pore-forming agent and baking the molded product. It is used as a porous halide absorber (porous body).

  By mixing a molding assistant with a pore-forming agent and adding moisture to the inexpensive sodium aluminate powder, the mixture is kneaded, and the mixture is shaped and fired to form pores at the site of the pore-forming agent, A halide absorber containing porous sodium aluminate can be obtained. In addition, air is mixed in the process of kneading, and carbon dioxide gas in the air is released, whereby pores are formed, and it is possible to obtain a halide absorbent containing porous sodium aluminate.

  The halide absorbent of the present invention can be manufactured using inexpensive raw materials by using sodium aluminate powder. Further, since the water is mixed and kneaded later, a large amount of energy is not required for drying, and the manufacturing cost can be suppressed.

  A first embodiment of the present invention will be described based on FIGS. 1 to 6.

  The situation of the production of the halide absorbent according to the first embodiment of the present invention will be described based on FIG. FIG. 1 conceptually shows the process for producing the halide absorbent according to the first embodiment of the present invention.

  As shown in the figure, a powder of sodium aluminate (sodium aluminate) 1 and a plasticizer 2 as a forming aid, a pore forming agent 3 and a strength reinforcing additive 4 (for example, glass fiber) are kneaded. That is, water is added and the raw materials are kneaded. Next, for example, a pellet-like raw material agent is produced by extrusion, and the raw material agent is preliminarily dried so that the shape can be maintained.

  After preliminarily drying the raw material, the raw material is calcined at a predetermined temperature to obtain a halide absorbent. The halide absorbent can be processed into particles, spheres, honeycombs and the like in addition to pellets, so that the flow of gas is not impeded when filled in a container or the like.

  Since sodium aluminate 1, plasticizer 2 and pore-forming agent 3 are mixed, water is added to form a kneaded product, and the mixture is fired, the pore-forming agent 3 is burned out to form pores, which are porous. It is possible to obtain a halide absorbent containing sodium chloride aluminate. In addition, air is mixed in the process of kneading, a gas component is formed by the reaction at the time of firing, and a pore is formed by releasing the generated gas, and halide absorption containing porous sodium aluminate is generated. Can be obtained.

  In the calcined halide absorbent, the interstices between particles become, for example, pores centered on the diameter of 5 μm (any diameter between 2 μm and 20 μm) (first peak), and The pores become, for example, pores centered at a diameter of 0.4 μm (any diameter between 0.1 μm and 1.0 μm) (second peak).

  The distribution of pores of the halide absorbent according to the first embodiment of the present invention, that is, the distribution of pore diameters at which the amount of pores of the pore diameter increases, will be described based on FIG. The distribution of pore size is derived by detecting the amount of penetration of mercury by the mercury intrusion method and measuring the size (diameter) and volume of the pore.

  FIG. 2 shows a graph for explaining the pore distribution of the halide absorbent according to the first embodiment of the present invention, in which the abscissa represents the pore diameter and the ordinate represents the pore volume. .

  Sodium aluminate powder (sodium aluminate) 1, plasticizer 2 as a molding assistant, pore former 3 introduced as an organic assistant, an inorganic assistant, or a mixture thereof, strength reinforcing additive 4 The halide absorbers prepared using this method have a large volume of pores distributed around a diameter of about 5 μm, that is, a large amount of pores (the amount of interstices between particles), as shown by the solid line in the figure. And a peak is present (first peak). Then, the volume of pores distributed around the diameter of about 0.4 μm, that is, the amount of pores (pores in particles) increases, and a peak is present (second peak).

  The presence of a plurality of pore diameters of the pore distribution of the halide absorbent can balance the degree of absorption (rate of absorption) of the halide (for example, HCl) and the state of volume change, and the halide The halide (eg, HCl) can be properly absorbed without the flow resistance of the gas containing (eg, HCl) becoming too high.

  In FIG. 2, the distribution of pores after the circulation of a simulation gas described later (after use) is shown by a dotted line.

The situation of the above-mentioned halide absorbent particles will be described based on FIG.
FIG. 3 is an explanatory view schematically showing the state of the pore structure formed by the aggregation of particles inside the halide absorbent according to the first embodiment of the present invention.

  As shown in the figure, gaps 12 (pores of about 5 μm in diameter) are formed between particles 11 of the composition constituting the halide absorbent, and pores 13 (about 0.4 μm in diameter) are formed in the particles 11 themselves. (Pores of) are formed. When a gas is introduced and a halide (for example, HCl) is absorbed, a volume change (expansion / contraction) occurs at the surface site of the pores 13 of the particles 11 and the particles are occluded. The gap 12 does not close even if a volume change (expansion / contraction) occurs, and the gas continues to penetrate toward the inside of the halide absorbent.

  Even if the volume change in the pores 13 in the particle 11, that is, even if the pore 13 of one particle 11 changes in volume and clogged, a halide (for example, HCl) is directed to the adjacent particle 11 Since the halide continues to penetrate through the gap 12, the halide (for example, HCl) penetrates toward the central particle 11, and the halide (for example, HCl) is introduced into the central particle 11 It can be soaked.

  The removal performance of the halide (for example, HCl) of the above-mentioned halide absorbent is described based on FIGS. 4 to 6.

  Figure 4 is a table that explains the composition, temperature, and pressure conditions of the simulated gas used to carry out the performance evaluation, and Figure 5 is a graph depicting the time-dependent change in concentration of halide (HCl) at the outlet. 6 shows a description of the composition before and after use of the halide absorbent.

As shown in FIG. 4, as the simulated gas, H ₂ O is 5.0 (volume%), CO is 20.0 (volume%), H ₂ is 12.0 (volume%), and CO ₂ is 5. A composition of 0 (vol%), CH ₄ 1.5 (vol%), N ₂ 56.4 (vol%), O ₂ 0.0 (vol%) and HCl 900 (ppm) was applied . The conditions for circulating the simulated gas are a temperature of 450 ° C. and a pressure (absolute pressure) of 0.98 (MPa).

  FIG. 5 shows the change with time of the concentration of HCl at the outlet of the container when the above-mentioned halide absorbent was filled in the container and the simulated gas was circulated under the conditions shown in FIG.

  The above-mentioned halide absorbents increase the amount of pores having a diameter of about 5 μm at the center of the distribution and pores having a diameter of about 0.4 μm at the center of the distribution to increase the first peak, the first peak, Since two peaks are present, HCl can be infiltrated into the pores 13 of the particles 11 present in the center.

  Therefore, as shown in the figure, the concentration of HCl can be maintained at a very low value until the predetermined time T, and then the concentration of HCl gradually increases, and the concentration of HCl becomes an initial value (900 ppm over a long period of time) Never reach). That is, it can be seen that HCl removal is performed well over a long period of time.

  That is, as shown by the dotted line in FIG. 2, a volume change occurs at the surface portion of the pores 13 of the particles 11 and the volume of pores of about 0.4 μm in diameter decreases, but a large gap between the particles 11 The amount of pore volume of about 5 μm diameter is maintained. This leaves a passage for the gas to penetrate and allows the gas to continue to penetrate towards the interior of the halide absorbent.

  The predetermined time T corresponds to the flow length of the container depending on the amount of the halide absorbent filled in the container, the concentration of the halide contained in the gas to be ventilated, and the operating conditions such as the temperature and pressure at which the removal is performed. And the width of the filling surface of the halide absorber, etc., and the result shown in FIG. 4 is not a verification of the absolute amount of removal but a verification of the removal tendency. It is.

  FIG. 6 shows the state of the composition (proportion of the composition of the compound) before and after the use of the above-mentioned halide absorbent.

  As shown in the figure, after use, sodium aluminate is significantly reduced and sodium carbonate has disappeared. Instead, sodium chloride is formed and alumina is significantly increased.

  When the halide absorber absorbs HCl, the sodium component remains converted to sodium chloride. In the halide absorbent of this example, most of the sodium component, which was present as a sodium aluminate or sodium carbonate compound before use, remains as sodium chloride after use, so that it absorbs HCl and the sodium component It turns out that it is used effectively. Also, since sodium is converted to sodium chloride, the aluminum component contained in sodium aluminate remains as alumina. This also indicates that the sodium component is effectively used by absorbing HCl.

  That is, in the halide absorbent in which the pore volume peak of the first example is present in a plurality of diameters, almost no sodium aluminate remains and no sodium carbonate remains after use, so It can be seen that the sodium component is effectively used upon absorption.

  In the first embodiment described above, the second peak has a diameter of 0.4 μm, ie, a diameter between 0.1 μm and 1.0 μm, but preferably has a diameter between 0.02 μm and 1.8 μm. It is also possible to make the diameter between 0.3 μm and 1.8 μm. In addition, although the example in which the first peak and the second peak are present has been described, the peak of the pore amount of the halide absorbent may have three or more peaks of other diameters. That is, multiple pore distribution may be formed in the halide absorbent.

  The above-mentioned halide absorbent is a porous halide absorbent containing sodium aluminate capable of removing halide, having a diameter of about 5 μm (any diameter between 2 μm and 20 μm), about 0 Since the porous body has a pore diameter with a diameter of 4 μm (any diameter between 0.1 μm and 1.0 μm) and a peak in which the volume, ie, the amount of pores, increases, the halide (HCl) is Even if it is absorbed and a volume change occurs, it is suppressed that all pores are blocked and the flow of gas is prevented. For this reason, even if a volume change occurs, it is possible to suppress a decrease in the absorption performance of halide (HCl).

  A second embodiment of the present invention will be described based on FIG. 7 to FIG.

  The situation of the production of the halide absorbent according to the second embodiment of the present invention will be described based on FIG. FIG. 7 conceptually shows the process for producing the halide absorbent according to the second embodiment of the present invention. The same members as those shown in FIG. 1 are denoted by the same reference numerals.

  As shown in the figure, sodium aluminate powder (sodium aluminate) 1, plasticizer 2 as a forming aid, second plasticizer 22 as a forming aid different in type from plasticizer 2, pore formation The agent 3 and the strength reinforcing additive 4 (for example, glass fiber) are kneaded. That is, water is added and the raw materials are kneaded. Next, for example, a pellet-like raw material agent is produced by extrusion, and the raw material agent is preliminarily dried so that the shape can be maintained.

  After preliminarily drying the raw material, the raw material is calcined at a predetermined temperature to obtain a halide absorbent. The halide absorbent can be processed into particles, spheres, honeycombs and the like in addition to pellets, so that the flow of gas is not impeded when filled in a container or the like.

  Since sodium aluminate 1, plasticizer 2, second plasticizer 22 and pore forming agent 3 are mixed, water is added to form a kneaded product, and the mixture is fired, the pore forming agent 3 is burned out and pores Is formed to obtain a halide absorber containing porous sodium aluminate. In addition, air is mixed in the process of kneading, a gas component is formed by the reaction at the time of firing, and a pore is formed by releasing the generated gas, and halide absorption containing porous sodium aluminate is generated. Can be obtained.

  In the calcined halide absorbent, the interstices between particles become, for example, pores centered on the diameter of 5 μm (any diameter between 2 μm and 20 μm) (first peak), and For example, a pore whose center is (second peak) having a diameter of about 1.3 μm (any diameter between 0.3 μm and 1.8 μm) and a diameter of about 0.1 μm (0 .2) A pore having a center (third peak) as an arbitrary diameter between .02 and 0.2 .mu.m.

  The distribution of pores of the halide absorbent according to the second embodiment of the present invention, that is, the distribution of pore diameters at which the amount of pores of the pore diameter increases, will be described based on FIG. The distribution of pore size is derived by detecting the amount of penetration of mercury by the mercury intrusion method and measuring the size (diameter) and volume of the pore.

  FIG. 8 shows a graph for explaining the pore distribution of the halide absorbent according to the second embodiment of the present invention, in which the abscissa represents the pore diameter and the ordinate represents the pore volume. .

  Sodium aluminate powder (sodium aluminate) 1, plasticizer 2 as forming aid, second plasticizer 22 as forming aid, organic aid, inorganic aid, or a mixture thereof The halide absorbent prepared using the pore-forming agent 3 and the strength-reinforcing additive 4 has a volume of pores distributed around a diameter of about 5 μm, that is, the amount of pores (particle amount (particles), as shown by the solid line in the figure. There is a peak (the first peak) due to an increase in the amount of interstices between the and particles. Then, the volume of pores distributed around the diameter of about 1.3 μm, that is, the amount of pores (pores in particles) increases and a peak is present (second peak), the diameter of about 0.1 μm The volume of pores distributed around the center, that is, the amount of pores (pores in the particles) increases, and a peak is present (third peak).

  By making the diameter of the peak of the pore distribution of the halide absorbent plural in three types of diameters, the degree of absorption (absorption rate) of the halide (for example, HCl) and the state of volume change are finely balanced The halide (for example, HCl) can be properly absorbed without the flow resistance of the gas containing the halide (for example, HCl) becoming too high.

  In FIG. 8, the distribution of pores after the circulation of a simulation gas described later (after use) is shown by a dotted line.

  The situation of the particles of the halide absorber of the second embodiment will be described with reference to FIG. 3. The gaps 12 (pores of about 5 μm in diameter) between the particles 11 of the composition constituting the halide absorber Are formed, and the pores 13 of the particle 11 itself are formed of pores of 1.3 μm in diameter and pores of about 0.1 μm in diameter. When a gas is introduced and a halide (for example, HCl) is absorbed, a volume change (expansion / contraction) occurs at the surface site of the pores 13 of the particles 11 and the particles are occluded. The gap 12 does not close even if a volume change (expansion / contraction) occurs, and the gas continues to penetrate toward the inside of the halide absorbent.

  Even if the volume change proceeds in the pores 13 in the particles 11, that is, the pores 13 (pores with a diameter of 1.3 μm, pores with a diameter of about 0.1 μm) of one particle 11 change in volume. Even if a blockage occurs, the halide (for example, HCl) permeates toward the central particle 11 because the halide (for example, HCl) continues to penetrate through the gap 12 toward the adjacent particle 11 Inclusion, halide (e.g., HCl) can be impregnated into the core 11 particles.

  As in the first example, a simulated gas (see FIG. 4) was circulated to confirm the temporal change in concentration of the halide (HCl) at the outlet. As in the first embodiment, it was confirmed that the concentration of HCl was maintained at a very low value until the predetermined time T (see FIG. 5), and that the removal of HCl was performed well over a long period of time .

  That is, as shown by the dotted line in FIG. 8, a volume change occurs at the surface portion of the pore 13 of the particle 11, and the volume of the pore of about 1.3 μm and the pore of about 0.1 μm are Although reduced, the amount of volume of pores of about 5 μm diameter, which is a large gap between particles 11, is maintained. This leaves a passage for the gas to penetrate and allows the gas to continue to penetrate towards the interior of the halide absorbent.

  FIG. 9 shows the state of the composition (proportion of the composition of the compound) before and after the use of the above-mentioned halide absorbent.

  As shown in the figure, as in the first embodiment, after use, sodium aluminate is significantly reduced and sodium carbonate is eliminated. Instead, sodium chloride is formed and alumina is significantly increased.

  That is, in the halide absorbent in which the pore volume peak of the second embodiment is present at three or more diameters, almost no sodium aluminate remains after use and no sodium carbonate remains after use, It is understood that the sodium component is effectively used by absorbing HCl.

  The above-mentioned halide absorbent is a porous halide absorbent containing sodium aluminate capable of removing halide, having a diameter of about 5 μm (any diameter between 2 μm and 20 μm), about 1 .3 .mu.m diameter (any diameter between 0.3 .mu.m and 1.8 .mu.m), pore diameter of about 0.1 .mu.m (any diameter between 0.02 .mu.m and 0.2 .mu.m), volume, i.e. Since the porous body has a peak where the amount of pores increases, it is suppressed that all pores are blocked and the flow of gas is impeded even if the halide (HCl) is absorbed and the volume change occurs. Ru. For this reason, even if a volume change occurs, it is possible to suppress a decrease in the absorption performance of halide (HCl).

  A comparative example will be described based on FIGS. 10 to 13.

  FIG. 10 shows a graph for explaining the pore distribution of the halide absorbent of the comparative example. In the figure, the horizontal axis is the pore size and the vertical axis is the pore volume. FIG. 10 is a graph corresponding to FIG. 2 and FIG.

  As a comparative example, a halide absorbent (made without using a pore forming agent 3) prepared using sodium aluminate powder (sodium aluminate) 1 and a plasticizer 2 as a forming aid is shown in FIG. As shown by the solid line, the volume of pores distributed around a diameter of about 1 μm, that is, the amount of pores (the amount of interstices between particles) increases, and there is one peak .

  The situation of the particles of the halide absorbent of the comparative example will be described based on FIG.

  FIG. 11 is an explanatory view schematically showing the state of the pore structure formed by the aggregation of particles inside the halide absorbent of the comparative example. FIG. 11 is an explanatory view corresponding to FIG.

  As shown in the figure, gaps 16 (pores with a diameter of about 1 μm) are formed between particles 15 of the composition constituting the halide absorbent. When a gas is introduced to absorb the halide (for example, HCl), a volume change occurs in the gaps 16 (pores) between the particles 15, causing a blockage in a short time and the halide (for example, HCl) It becomes difficult to penetrate toward the center.

  That is, as shown by a dotted line in FIG. 10, a volume change occurs at the surface portion of the gap 16 (pores) between the particles 15, the volume of the gap 16 decreases, and the passage through which the gas penetrates is not crushed. The gas can not continue to penetrate toward the inside of the halide absorbent.

  The removal performance of the halide (for example, HCl) of the halide absorber of the comparative example will be described based on FIG. 12 and FIG.

  FIG. 12 shows the time course of the concentration of HCl at the outlet of the container when the container was filled with the halide absorbent of the comparative example and the simulated gas was circulated under the conditions shown in FIG. FIG. 12 is an explanatory view corresponding to FIG.

  In the halide absorber of the comparative example, since the peak of the pore diameter at which the amount of pores increases is one, the halide (for example, HCl) is less likely to penetrate toward the center. Therefore, as shown in the figure, the concentration of HCl rapidly increases in an early time, and then the concentration of HCl gradually increases. For this reason, it turns out that the concentration of HCl approaches the initial value (900 ppm) in a short time, and the removal of HCl can not be performed for a long time.

  FIG. 13 shows the state of the composition (proportion of the composition of the compound) before and after the use of the halide absorbent of the comparative example. FIG. 13 corresponds to the situation of FIG. 6 and FIG.

  As shown in the figure, sodium aluminate and sodium carbonate decrease after use. And sodium chloride and alumina are increasing.

  From the fact that sodium chloride remains after use in the halide absorbent of the comparative example, it is understood that the sodium component is used by absorbing HCl. In addition, sodium aluminate remains as alumina because sodium is converted to sodium chloride.

  However, compared to the halide absorbent of this example shown in FIG. 6 and FIG. 9, the reduction rate of sodium aluminate and sodium carbonate is small, and although it absorbs HCl, sodium aluminate and carbonated after use It can be seen that both sodium remains unreacted, leaving room for the use of the sodium component.

  That is, the halide absorbents of the first and second examples in which the peak of the pore amount exists at a plurality of diameters are the halide absorbers of the comparative example in which the peaks of the pore amount exist at one diameter. On the other hand, the sodium component can be used effectively to remove HCl well over a long period of time.

  Therefore, by using the halide absorbent of this example, it is possible to suppress the decrease in the absorption performance of the halide (HCl) even if the volume change occurs in the pores due to the absorption of the halide (HCl). Becomes possible.

  The present invention can be used in the industrial field of halide absorbents.

1 sodium aluminate 2 plasticizer 3 pore-forming agent 4 strength reinforcing additive 11 particles 12 interstices 13 pores 22 second plasticizer

Claims (6)

A porous halide absorber comprising sodium aluminate capable of removing halide, comprising
A porous body in which there is a peak where the amount of pores increases with a plurality of pore sizes ,
The peak where the amount of pores in the pore diameter increases is
A first peak at a pore size of between 2 μm and 20 μm,
A halide absorber characterized in that a second peak at a pore size of between 0.1 μm and 1.0 μm is present . A porous halide absorber comprising sodium aluminate capable of removing halide, comprising
A porous body in which there is a peak where the amount of pores increases with a plurality of pore sizes ,
The peak where the amount of pores in the pore diameter increases is
A first peak at a pore size of between 2 μm and 20 μm,
A halide absorbent characterized in that a second peak at a pore size of between 0.02 μm and 1.8 μm is present . In the halide absorbent according to claim 2 ,
The halide absorbent, wherein the second peak has a pore size of between 0.3 μm and 1.8 μm. A porous halide absorber comprising sodium aluminate capable of removing halide, comprising
A porous body in which there is a peak where the amount of pores increases with a plurality of pore sizes ,
The peak where the amount of pores in the pore diameter increases is
A first peak at a pore size of between 2 μm and 20 μm,
A second peak at a pore size of between 0.3 μm and 1.8 μm,
A halide absorbent characterized in that a third peak at a pore size of between 0.02 μm and 0.2 μm is present . In the halide absorbent according to any one of claims 1 to 3 ,
A halide absorbent characterized in that it is molded using sodium aluminate powder, a molding aid, and a pore-forming agent as raw materials. In the halide absorbent according to claim 4 ,
A halide absorbent characterized in that it is molded by using sodium aluminate powder, a plurality of types of forming aids, and a pore-forming agent as raw materials.

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