JP2006175326A - Dioxin adsorbing/removing agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dioxin adsorbing/removing agent exhibiting excellent dioxin removal performance over a long period of time. <P>SOLUTION: This dioxin adsorbing/removing agent contains a porous carrier to which a hydrophobic organic substance is added and stuck. The hydrophobic organic substance is selected from the group consisting of gas oil, heavy oil, coal tar and naphthalene. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a dioxin adsorption / removal agent.

  Conventionally, various methods and adsorption removal agents have been used to adsorb and remove dioxins generated during the treatment of industrial waste.

  For example, Patent Document 1 discloses a carbon system having low dioxin generation catalytic ability for the purpose of efficiently reducing and dioxin concentration by efficiently adsorbing and removing dioxins and preventing the formation of dioxins. A dioxin adsorption / removal agent comprising an adsorbent is disclosed.

  Patent Document 2 discloses that dioxins adsorbed on a carbonaceous adsorbent such as activated carbon or activated coke by performing a predetermined heat treatment in a reaction vessel filled with a carbonaceous adsorbent adsorbed with dioxins. A method for low-temperature pyrolysis of dioxins is disclosed, which decomposes water with higher efficiency.

However, when dioxin treatment is performed using the adsorbents described in Patent Document 1 and Patent Document 2, acid gas, basic gas, or water vapor generated together with dioxin adheres to the adsorbent and is removed from dioxin. The problem that performance deteriorates arises.
Japanese Patent Laid-Open No. 10-99677 Japanese Patent Laid-Open No. 11-76756

  An object of this invention is to provide the adsorption removal agent which exhibits the outstanding dioxin removal performance over a long period of time.

  The dioxin adsorption / removal agent according to the present invention includes a porous carrier to which a hydrophobic organic substance is attached.

  ADVANTAGE OF THE INVENTION According to this invention, the adsorption removal agent which exhibits the dioxin removal performance excellent over the long term can be provided.

  As a result of intensive studies by the present inventors to solve the above problems, the dioxin removal performance of the carbon-based adsorbents of Patent Document 1 and Patent Document 2 described above is deteriorated because the carbon-based adsorbent that is originally hydrophobic is used. It has hydrophilicity by adsorbing water vapor, and also has acidic gas (for example, hydrogen sulfide, sulfur dioxide, sulfuric acid, hydrogen chloride, hydrogen bromide, hydrogen iodide, nitric acid) and basic gas (for example, ammonia). It is caused by the fact that the white compounds (for example, ammonium sulfate, ammonium chloride, ammonium bromide, ammonium iodide, ammonium nitrate, etc.) produced by the reaction of the adsorbent adhere to the adsorbent surface to promote hydrophilicity. I found it. That is, since dioxin is hydrophobic, the adsorbent with enhanced hydrophilicity cannot sufficiently remove dioxin.

  The present inventors can prevent the adsorption of water vapor and suppress the adhesion of white compounds caused by acidic gas and basic gas by using a hydrophobic organic material attached to a porous carrier. I found. The present invention is based on these findings.

  Hereinafter, various embodiments of the dioxin adsorption / removal agent according to the present invention will be described.

  The dioxin adsorption / removal agent according to the present invention includes a porous carrier to which a hydrophobic organic substance is attached.

  Examples of the porous carrier include activated carbon, zeolite, silica-alumina composite oxide and the like. Among them, activated carbon is hydrophobic, so it originally has a removal effect on dioxins, but by adhering a hydrophobic organic substance to this, adsorption of water vapor and adhesion of white compounds can be suppressed, and long-life A dioxin adsorption removing agent can be obtained. On the other hand, since zeolite and silica-alumina composite oxide are hydrophilic, it is difficult to adsorb and remove dioxin which is hydrophobic as it is. However, by attaching a hydrophobic organic substance, it is possible to impart dioxin removal performance to the zeolite and silica-alumina composite oxide, and it is possible to suppress adsorption of water vapor and adhesion of white compounds.

  Examples of the hydrophobic organic material include petroleum-based materials obtained from crude oil as a raw material and coal-based materials obtained from coal as a raw material. Examples of petroleum substances include light oil and heavy oil. Examples of the coal-based material include coal tar and naphthalene. Hydrophobic organic substances selected from the group consisting of light oil, heavy oil, coal tar and naphthalene are not only easy to handle, but also can provide a long-life adsorption remover. These hydrophobic organic substances can be used alone or in combination of two or more.

  The hydrophobic organic substance is preferably attached at a ratio of 0.1 to 30% by mass of the porous carrier mass.

  If the amount of the hydrophobic organic substance attached is less than 0.1% by mass, the adsorption / removal agent may not be sufficiently extended in life. On the other hand, when the amount of the hydrophobic organic substance added exceeds 30% by mass, the pores of the porous carrier are blocked and the adsorption performance tends to be lowered. A more preferable range of the amount of the hydrophobic organic substance attached is 1 to 10% by mass of the porous carrier mass. If it is in this range, particularly excellent dioxin adsorption performance can be exhibited over a longer period.

  Such a dioxin adsorption / removal agent can be produced, for example, as described below.

  When the hydrophobic organic material is a liquid material such as light oil, heavy oil, coal tar, etc., the hydrophobic organic material is put into a sprayer, sprayed onto a porous carrier, attached, and dried. Can do. In particular, in the case of coal tar with high viscosity, it is manufactured by appropriately heating the sprayer to make the coal tar low viscosity, spraying and adhering it to the heated porous carrier under pressure, and then drying. can do. According to this method, a dioxin adsorption / removal agent in which a porous carrier is coated with a hydrophobic organic substance can be prepared. Therefore, a long-life adsorption / removal agent with higher hydrophobicity and superior dioxin adsorption performance can be obtained. Can be realized.

  When the hydrophobic organic material is naphthalene, it can be produced, for example, as described below.

  It can be produced by dissolving a certain amount of naphthalene in various solvents such as ethanol, ether, carbon disulfide, benzene and the like, putting it in a sprayer, spraying it on a porous carrier, attaching it, and drying it.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

[Example]
Hereinafter, the dioxin adsorption removing agent according to the present invention will be described with reference to examples.

<Manufacture of dioxin adsorption remover>
Example 1
As described below, 100 g of activated carbon was coated with 3 g of light oil and dried at 100 ° C. for 5 to 10 hours to obtain a dioxin adsorption / removal agent.

  That is, activated carbon was coated with light oil by rotating activated carbon on a bread granulator and spraying light oil on the bread granulator. The amount of light oil impregnation was determined from the mass difference before and after spraying of the sprayer containing light oil.

(Comparative Example 1)
The same kind of activated carbon as Example 1 was used as the dioxin adsorption / removal agent of Comparative Example 1.

<Hydrophobic evaluation>
About 10 g each of the dioxin adsorption / removal agents obtained in Example 1 and Comparative Example 1 were packed in 20 mmφ columns. Saturated adsorption was performed on these columns by flowing air gas with humidity adjusted to 30% on a mass basis at a temperature of 25 ° C. at a flow rate of 5 L / min, and the equilibrium adsorption amount at this time was measured. Here, the equilibrium adsorption amount is the difference between the mass when the mass of the dioxin adsorption / removal agent becomes substantially constant when the air gas is circulated and the mass of the dioxin adsorption / removal agent before the air gas circulation. Is expressed as a percentage with respect to the mass of the dioxin adsorption / removal agent before circulation of air gas.

  Next, the humidity of the air gas was increased, and the equilibrium adsorption amount was measured in the same manner, and the measurement was performed until the humidity of the air gas reached 80%. Subsequently, the moisture adsorbed by the adsorption / removal agent was desorbed by successively lowering the humidity of the air gas to 0% by mass, and the equilibrium adsorption amount at this time was similarly measured. The results obtained at this time are shown in FIG. In FIG. 1, the vertical axis represents the equilibrium adsorption amount (% by mass), and the horizontal axis represents the humidity (%) of the air gas. Further, in FIG. 1, the solid line X indicates the result at the time of adsorption in Example 1, the broken line Y indicates the result at the time of desorption in Example 1, and the solid line Z indicates the result of Comparative Example 1. The broken line W shows the result at the time of desorption of Comparative Example 1.

  As is clear from FIG. 1, the dioxin adsorption / removal agent of Example 1 had a low equilibrium adsorption amount of 11.2% by mass at a humidity of 80% and was excellent in hydrophobicity. On the other hand, the adsorption removal agent of Comparative Example 1 that was not coated with light oil had a high equilibrium adsorption amount of 18.0% by mass at a humidity of 80%, and had a higher moisture adsorption amount than the adsorption removal agent of Example 1. It was. Even when the humidity was lower than 80%, the adsorption / removal agent of Example 1 tended to have a smaller amount of moisture adsorption than Comparative Example 1 during both moisture adsorption and desorption.

<Evaluation of whitening suppression effect>
Each 10 g of the dioxin adsorption / removal agent obtained in Example 1 and Comparative Example 1 was packed in a 20 mmφ column. In these columns, air gas containing 10% by volume of hydrogen chloride gas and humidity adjusted to 60% on a mass basis was passed at a temperature of 25 ° C. for 1 hour at SV (space velocity) of 6000 / hour. Subsequently, air gas similar to that described above was allowed to flow for 12 hours under the same flow conditions as described above except that ammonia gas was included in a volume of 200 ppm instead of hydrogen chloride gas. Each column photo after gas distribution was taken. A photograph of the column packed with the adsorption removing agent of Example 1 is shown in FIG. 2, and a photograph of the column packed with the adsorption removing agent of Comparative Example 1 is shown in FIG.

  As is clear from FIGS. 2 and 3, the dioxin adsorption / removal agent of Example 1 was not whitened as compared with the dioxin adsorption / removal agent of Comparative Example 1, and the amount of white compound adhered was small.

<Evaluation of dioxin removal performance>
In an industrial waste treatment plant, 20 tons of the dioxin adsorption / removal agent of Example 1 is packed in one of the adsorption towers for dioxins, and the gas generated during the treatment of the waste in this adsorption tower is SV 1500 / hour for 20 months. Aerated. The dioxin concentrations of the input gas and the output gas at this time were measured for each elapsed time, and the results are shown in FIG. In FIG. 4, the horizontal axis indicates the ventilation time (months), and the vertical axis indicates the dioxin concentration (ng-TEQ / m ³ N).

Moreover, the dioxin removal performance of Comparative Example 1 was also evaluated in the same manner as in Example 1. The results are also shown in FIG. In addition, the dioxin emission control value of this industrial waste treatment plant was 0.1 ng-TEQ / m ³ N.

  As is clear from FIG. 4, the dioxin adsorption / removal agent of Example 1 had a long life of 19 months because the dioxin concentration of the outgas exceeded the regulation value after 20 months had elapsed. In addition, it showed excellent dioxin removal performance when the dioxin concentration of the incoming gas became high.

  On the other hand, the dioxin adsorption / removal agent of Comparative Example 1 had a lifetime of 12 months and was shorter than that of Example 1, and the dioxin removal performance was also low.

The characteristic diagram which shows the relationship between the humidity of air gas, and the equilibrium adsorption amount of a dioxin adsorption removal agent. The photograph of the column packed with the dioxin adsorption removal agent of Example 1. The photograph of the column packed with the dioxin adsorption removal agent of the comparative example 1. The characteristic line figure which shows the dioxin removal performance of the dioxin adsorption removal agent of Example 1 and Comparative Example 1. FIG.

Claims (3)

  A dioxin adsorption / removal agent comprising a porous carrier to which a hydrophobic organic substance is attached.   The dioxin adsorption / removal agent according to claim 1, wherein the hydrophobic organic substance is selected from the group consisting of light oil, heavy oil, coal tar, and naphthalene.   The dioxin adsorption / removal agent according to claim 1 or 2, wherein the hydrophobic organic substance is attached at a ratio of 0.1 to 30% by mass of the porous carrier mass.

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