JP2014061480A - Absorbent producing method and absorbent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To expand use of unburned carbon obtained by a wet decarbonization process of coal ash and the like.SOLUTION: In a method for producing an absorbent, unburned carbon, to which a scavenger for separating unburned carbon from a substance containing the unburned carbon adheres, is washed with a solvent to obtain unburned carbon from which the scavenger has been removed. The absorbent can be obtained by removing the scavenger, such as light oil, adhering to the surface of the unburned carbon. Since the absorbent contains hydrophobic solid unburned carbon, which is a porous carbonaceous particle having hydrophobicity, the absorbent can scavenge organochlorine compounds, such as lipophilic dioxins and PCB, and can reduce or control their concentrations by being added to flue gas or the like. The scavenger may be a scavenger having been used when separating unburned carbon from coal ash by flotation. An absorbent having a specific surface area of 50 m/g or more and an absorbent having a volume of micro holes having a hole diameter of less than 2 nm of 0.0040 ml/g or more can be obtained.

Description

  The present invention relates to a method for producing an adsorbent from unburned carbon obtained by a wet decarburization process such as coal ash, and an adsorbent produced by the method.

  Conventionally, coal ash generated at coal-fired thermal power plants uses coal ash with low unburned carbon as a raw material for cement, etc., and coal ash with a high unburned carbon content cannot be used effectively. Landfilled as industrial waste.

  Therefore, as described in Patent Document 1 and the like, after adding water to coal ash to form a slurry, adding a collecting agent to the slurry, and applying a shearing force to the slurry and the collecting agent to perform surface modification In the flotation process, unburned carbon of coal ash is attached to the air bubbles and floated, and the unburned carbon separated by flotation is used as the fuel, and the coal ash with an unburned carbon content of 1% by weight or less (product ) Is used as a mixture for cement and a raw material for manufacturing lightweight aggregates.

Japanese Patent No. 3613347

  However, unburned carbon recovered by the above-mentioned conventional wet decarburization processes such as coal ash can be reused as fuel, but the amount of treatment is limited only by reuse as fuel. The development of was demanded.

  Then, this invention is made | formed in view of said point, Comprising: It aims at expanding the use of the unburned carbon obtained by wet decarburization processes, such as coal ash.

  In order to achieve the above-mentioned object, the present invention provides a method for producing an adsorbent, wherein unburned carbon with a scavenger attached to the surface for separating unburned carbon from a substance containing unburned carbon is used as a solvent. It is characterized by obtaining unburned carbon from which the scavenger has been removed by washing. Thereby, collection agents, such as light oil adhering to the surface of unburned carbon, can be removed and an adsorbent can be obtained. Since this adsorbent contains hydrophobic solid unburnt carbon, which is porous carbonaceous particles having hydrophobicity, it can capture lipophilic dioxins, organochlorine compounds such as PCB, and combustion exhaust gas. It is possible to reduce or control these concentrations by adding them.

  In the adsorbent manufacturing method, the scavenger can be used when separating unburned carbon from coal ash by flotation, using a scavenger such as light oil from coal ash. When unburned carbon is recovered by flotation, an adsorbent can be obtained from the unburned carbon.

Moreover, this invention is an adsorbent manufactured by the said method, Comprising: The specific surface area of this adsorbent can be 50 m < ² > / g or more, and an adsorbent with a high specific surface area can be obtained. Further, an adsorbent having a micropore having a diameter of less than 2 nm of 0.0040 ml / g or more can be obtained.

  As described above, according to the present invention, it is possible to produce an adsorbent from unburned carbon recovered by a wet decarburization process such as coal ash and to expand the application of unburned carbon.

It is a flowchart which shows the manufacturing method of the adsorbent which concerns on this invention. It is a graph which shows the test result of the adsorbent which concerns on this invention.

  Next, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

In the wet decarburization process of coal ash and the like described in Patent Document 1 and the like, a scavenger such as light oil, kerosene, and heavy oil is used when unburned carbon is separated from coal ash by flotation. Therefore, the scavenger adheres to the surface of the unburned carbon, and the pores (particularly micropores) of the unburned carbon are covered. Comparative Example 1 in Table 1 and FIG. 2 shows unburned carbon recovered from such a wet decarburization process, the volume of micropores having a diameter of less than 2 nm is 0.0000 mL / g, and the specific surface area is 19 As small as 0.7 m ² / g, it cannot be used as an adsorbent as it is. The specific surface area and mesopore pore volume were measured using Shimadzu Micromeritics ASP-2400 (manufactured by Shimadzu Corporation).

  Therefore, after receiving unburned carbon recovered from the wet decarburization process in step S1 of FIG. 1, the received unburned carbon is washed with a solvent such as toluene, benzene, hexane, etc. in step S2. In addition to these, other solvents can be used as long as they can process light oil or the like as a collecting agent with a solvent.

By the solvent treatment, a scavenger such as light oil on the surface of the unburned carbon is removed, the pores are restored, and a hydrophobic solid unburned carbon having a large specific surface area is obtained. The examples in Table 1 and FIG. 2 show the cleaned product thus obtained, the micropore volume is 0.0045 mL / g, and the mesopore and macropore volumes are also compared to Comparative Example 1. Has increased. Further, the specific surface area is 57.5 m ² / g, which is significantly increased as compared with Comparative Example 1, and can be suitably used as an adsorbent.

  Comparative Examples 2 and 3 are adsorbents obtained by liquid-liquid extraction of a raw material containing unburnt carbon separately using a nonpolar organic solvent and water. It can be seen that the product is comparable to the quality of the adsorbent. Comparative Examples 2 and 3 have different properties because the origins of raw materials containing unburned carbon are different.

  Next, in step S3 of FIG. 1, the solvent containing a scavenger such as light oil after the unburned carbon cleaning process is performed using a difference in boiling points (for example, light oil: about 180 to 300 ° C., toluene: about 110 ° C), and the separated light oil, etc. is reused as a scavenger for removing unburned carbon from coal ash via flotation, and the separated toluene is reused as a solvent. Can do.

  As described above, according to the present invention, not only the unburned carbon recovered in the wet decarburization process such as coal ash is reused as the fuel, but the unburned carbon is washed with a solvent and reused as an adsorbent. It can be used, and the application of unburned carbon can be expanded.

Claims (5)

  A scavenger for separating the unburned carbon from a substance containing unburned carbon is washed with a solvent to remove the unburned carbon attached to the surface, thereby obtaining unburned carbon from which the scavenger has been removed. Production method of adsorbent.   The method for producing an adsorbent according to claim 1, wherein the scavenger is used when separating unburned carbon from coal ash by flotation.   An adsorbent produced by the method according to claim 1 or 2. The adsorbent according to claim 3, wherein the specific surface area is 50 m ² / g or more.   The adsorbent according to claim 3, wherein micropores having a diameter of less than 2 nm are 0.0040 ml / g or more.

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