KR20050091147A - An adsorbent for removing dioxin and method for producing the adsorbent - Google Patents

Abstract

The present invention relates to an adsorbent, and more particularly, to an adsorbent for dioxin removal using activated carbon and natural zeolite, and a method of preparing the adsorbent.

According to the adsorbent according to the present invention and the method for producing the adsorbent, the adsorbent obtained by CaCl ₂ treatment of 34 μm or less of powdered activated carbon or the treatment of natural zeolite of 34 μm or less with HCl solution, respectively or in a fixed ratio. Not only can it be used at high temperatures, but it also has a good effect of removing dioxin and acid gas at the same time.

Description

An adsorbent for dioxin removal and a method for preparing the adsorbent {AN ADSORBENT FOR REMOVING DIOXIN AND METHOD FOR PRODUCING THE ADSORBENT}

The present invention relates to an adsorbent, and more particularly, to an adsorbent for dioxin removal using activated carbon and natural zeolite, and a method of preparing the adsorbent.

Dioxins are the generic name for 75 isomers of polychlorinated Dibenzo-p-dioxins (PCDDs) and 135 types of isomers of polychlorinated Dibenzo Furans (PCDFs). Polychlorinated dibenzo-p-dioxins (PCDDs) / polychlorinated dibenzofurans (PCDFs), which are called dioxins, are not substances that existed in nature. The materials of dioxins or furans are other materials having different properties depending on the number and position of chlorine substitution, but are generally referred to as dioxins.

These dioxins are mainly generated in various industrial processes and incineration processes, such as incineration of municipal waste and bleaching in the production process of chlorine compounds. Especially, dioxin compounds generated in urban waste incinerators, industrial waste incinerators, medical waste incinerators, etc. As a highly toxic substance that causes birth defects and birth defects, a large amount of waste is emitted from waste incinerators.

In other words, since dioxin is lipid-soluble, it is insoluble in water and difficult to be decomposed into microorganisms. Therefore, it is almost permanently decomposed in the natural world, so its toxicity is almost permanent, and it accumulates in fatty tissues of organisms and acts as an environmental hormone. This is because not only adversely affects but also a very small amount can cause the human reproductive and immune system disorders, and cancer, because it can threaten not only the environment but also the health and life of people.

One of the methods of evaluating the risk of dioxin is the introduction of dioxin toxicity factors (TEF) and toxic equivalents (TEQ) to indicate the degree of risk. In this method, first, Toxicity Equivalency Factors (TEF) of various types of dioxins are obtained, and the Toxic Equivalents (TEQ) are obtained by multiplying the Toxic Equivalency Factors (TEQ) by the concentrations of the Dioxins used. It is to calculate the degree of harm of dioxin by calculating. At this time, the toxicity index is based on the toxicity of 2,3,7,8-TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxane), which is the most toxic among dioxins, as reference value 1, and various types of dioxins Relative toxicity obtained for.

The main source of dioxin generation varies from country to country, but in general, the manufacturing, incineration, and thermal processes of chemicals are the main sources. Dioxins are produced as by-products during the production and use of chlorine organic chemicals, incineration of waste, or heat treatment. For example, when chlorine organic chemicals are manufactured, dioxins may be produced in the manufacturing process, and dioxins may be contained in the produced chlorine organic chemicals. Chlorophenol and its derivatives generated during incineration or heat treatment of waste can lead to the generation of dioxins.

As such, as the treatment of dioxins that are harmful to the environment and living organisms has emerged as an important problem, various methods of treating dioxins have been studied. Dioxins may be removed by adsorbing dioxins to adsorbents or by decomposing dioxins using a catalyst in order to remove dioxins contained in a flue gas.

As a method of removing dioxins using an adsorbent, there is a method of adsorbing and removing dioxins on activated carbon. Adsorption using activated carbon is a widely used method, in which powder activated carbon is injected into a flue gas pipe in a predetermined amount, and when the injected activated carbon adsorbs dioxins, the activated carbon is removed in a dust collector.

Korean Patent Registration No. 241771 and Japanese Patent Application Laid-Open No. Hei 10-277335 disclose a method and an apparatus for removing activated carbon by adsorbing dioxins by injecting activated carbon into flue gas. The above methods are widely used because of their simplicity and efficiency, but the existing activated carbon has a problem in that it is difficult to use the exhaust gas at about 200 ° C. or higher due to the risk of ignition when the temperature of the exhaust gas is high. In addition, since the surface area that actually adsorbs dioxin is only a fraction of the spray amount, using an activated dioxin for expensive dioxin is uneconomical and the dust collector installed in the rear stage to remove the activated carbon may be lost due to the ignition of the powder activated carbon described above. Concerns exist.

In order to solve this problem, Korean Patent Application No. 2001-83444 discloses an adsorbent using a zeolite powder having a particle size of at least 150 mesh and a) adsorbing dioxins by spraying natural zeolite powder into exhaust gas; And b) removing the dioxins adsorbed natural zeolite powder with a dust collector.

However, although the adsorbent using the zeolite powder provided by the patent application can be used at high temperatures, the problem remains that the adsorption efficiency of dioxins is lowered.

Therefore, there has been a lot of demand in the art for an adsorbent that can be used at high temperatures and has an excellent dioxin adsorption efficiency and at the same time can remove other harmful acid gases contained in exhaust gas.

In order to solve the above problems, it is an object of the present invention to provide an adsorbent based on activated carbon and a method for producing the adsorbent which improves the surface of activated carbon and reduces the risk of explosion at high temperatures.

Another object of the present invention is to provide a zeolite-based adsorbent and a method for producing the adsorbent, which have been subjected to acid treatment of zeolite of a certain particle size to improve adsorption capacity.

Another object of the present invention is to combine the adsorbents based on activated carbon and the adsorbents based on zeolite in a certain ratio, and not only to have excellent dioxin adsorption capacity, but also to remove other harmful acid gas contained in exhaust gas at the same time. It is to provide a method for producing an adsorbent.

Another object of the present invention is to provide a low cost adsorbent.

In order to achieve the above object, the present invention provides a supporting step of combining and processing activated carbon and CaCl ₂ solution; And it provides a method for producing an adsorbent for dioxin removal of activated carbon material comprising the drying step of drying the supported activated carbon at 120 ~ 200 ℃.

In the supporting step, the activated carbon and CaCl ₂ solution is characterized in that it is formulated at 80-95: 5-20% by weight.

The particle size of the activated carbon is characterized in that less than 34㎛.

The present invention also removes the adsorbent for dioxin removal of activated carbon material, which is prepared by any one of the above-described manufacturing methods.

The present invention also supports a step of combining the zeolite and HCl solution; A washing step of washing the zeolite after the supporting step with water; And it provides a method for producing an adsorbent for dioxins removal of zeolite material comprising the drying step of drying the washed zeolite until the water is completely removed.

In the compounding step, the zeolite and HCl solution is characterized in that the compounding of 75-85: 15-25% by weight.

The particle size of the zeolite is characterized in that less than 34㎛.

The present invention also provides an adsorbent for removing dioxins of a zeolite material, which is prepared by any one of the above-described manufacturing methods.

The present invention also provides a mixture material comprising 3-6: 4-7% by weight of an adsorbent for dioxin removal of activated carbon material and an adsorbent for dioxin removal of zeolite material prepared by any one of the above-mentioned manufacturing methods. Provided is an adsorbent for dioxin removal.

As described above, the present invention relates to an adsorbent for removing dioxins of activated carbon, an adsorbent for removing dioxins of zeolite, and an adsorbent for removing dioxins of dioxins and zeolites, and a method for preparing the adsorbent.

That is, even though dioxin in the flue gas discharged from the waste incinerator is included in the tar component in the flue gas, when activated carbon is used as a dioxin adsorbent as it is, the removal of the tar component itself is not necessarily sufficient. Pore of activated carbon is blocked by adhesion of tar component, and the ability to remove dioxins is reduced. Also, activated carbon which has not been treated at all is difficult to use at high temperatures because of the risk of explosion at high temperatures. In order to improve the surface of silver activated carbon, activated carbon was treated with calcium chloride solution (CaCl ₂ solution) to complete the adsorbent for dioxin removal of activated carbon.

Accordingly, the adsorbent for dioxin removal of activated carbon material according to the present invention, although Ca ions block micropores, the surface area is somewhat reduced but meso pores are developed, resulting in total pore volume. ) Increases by about 2 times, and Ca ions provide the adsorption point, which provides more adsorption opportunities with the adsorbed material (dioxin) and increases the adsorption energy.

Next, look at the method for producing a dioxin adsorbent of the activated carbon material according to the present invention, and includes a supporting step of combining the activated carbon and CaCl ₂ solution and a drying step of drying the supported activated carbon at 120 ~ 200 ℃. At this time, since the calcium is formed, it is not preferable that the adsorption point is lost because it is out of the temperature range.

In the supporting step, the activated carbon and CaCl ₂ solution are formulated at 80-95: 5-20% by weight, more preferably 88-89: 11-12% by weight. At this time, when the compounding weight% range is out of range, the effect of providing an additional adsorption point at the time of activated carbon adsorption becomes weak. In addition, the concentration of the calcium chloride solution on which the activated carbon is supported is preferably about 1 M, and the particle size of the activated carbon is preferably 34 μm or less, and the activated carbon is supported on the calcium chloride solution for 1 to 6 hours, more preferably 2 to 3 hours. It will be supported for time.

In addition, the drying step is to dry until the liquid component is removed, preferably 12 hours or more.

On the other hand, the zeolite can be used at a high temperature, but there is a problem that the adsorption capacity is low, so the present inventors have various studies to solve this problem, the specific surface area and pore volume increased by about 2 times by treating acid, especially hydrochloric acid solution to the zeolite It was found that the adsorption efficiency was improved to complete the adsorbent for removing dioxins of zeolite material, the adsorbent for removing dioxins of zeolite material was effective in removing not only dioxin but also harmful acid gas. The zeolite used in the present invention is more preferably a natural zeolite.

Next, looking at the method for preparing the adsorbent for removing dioxin of the zeolite material according to the present invention, the supporting step of combining the zeolite and HCl solution and the washing step of washing the zeolite through the supporting step with water and the washed zeolite completely moisture And drying to remove until removed.

Wherein in the compounding step the zeolite and HCl solution is formulated in a weight percent of 75-85: 15-25, more preferably in a weight percent of 82-80: 18-20. It is not preferable because the adsorption point is lost if it is out of the compounding range. In addition, the concentration of the hydrochloric acid solution to be mixed with the zeolite is preferably about 1M, and the particle size of the zeolite is preferably 34㎛ or less. More preferably, the compounding step is performed for about 3 hours while maintaining the zeolite and hydrochloric acid solution blended in the weight percent on a hot plate at about 90 ° C.

In addition, the washing step is preferably washed 15 times or more with water, preferably distilled water, more specific washing method is to pour distilled water in the blend and shake to remove the supernatant and then pour distilled water and wash 15 times or more in the same way It is.

In addition, the drying step is preferably performed until the water is completely removed at about 105 ℃ after washing.

When the adsorbent for dioxin removal of activated carbon material and the adsorbent for dioxin removal of acid treated zeolite material are added at a predetermined ratio, the spraying amount may be the same as that of the dioxin adsorption activated carbon used in the prior art. In addition to having the same level of dioxin adsorption capacity as well as reducing the risk of explosion at high temperatures, the adsorbent for dioxin removal of a compound material that simultaneously removes harmful other acid gases was developed at low cost.

The adsorbent for dioxin removal of the blended material may be prepared by mixing the adsorbent for dioxin removal of activated carbon material with the adsorbent for dioxin removal of acid treated zeolite material at a weight ratio of 3-6: 4-7. More preferably, the acid treated zeolite material is adsorbed at about 6: 4.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the above examples should not be construed as limiting the present invention.

Example 1

Preparation of Adsorbent for Dioxin Removal from Activated Carbon

1.Prepare activated carbon by pulverizing less than 34㎛ activated carbon or less than 34㎛ activated carbon, mix the prepared activated carbon and 1M calcium chloride solution at about 88: 12% by weight, leave it for 3 hours, load it, and support it. It was dried for 12 hours at to prepare an adsorbent (A3-1) for dioxin removal of activated carbon material.

2. Except that the drying temperature was 200 ℃ in the same manner as in 1. The dioxin removal adsorbent (A3-2) of the activated carbon material was prepared.

Experimental Example 1

BET was measured on commercially available activated carbon A3 commercially available and the adsorbents A3-1 and A3-2 for dioxin removal of activated carbon material obtained in Example 1, and the results are shown in Table 1.

absorbent Calcination Condition [℃] BET Specific surface area [㎡ / g} Pore Volume [cc / g] Median Pore [Å] A3 - 976.2440 0.348748 24.4359 A3-1 120 858.2251 0.626229 21.6039 A3-2 200 938.9734 0.669479 23.8698

The adsorbents A3-1 and A3-2 for dioxin removal of the activated carbon material obtained in Example 1 from Table 1 show that the Ca ions block micropores, so that the surface area is slightly reduced than that of commercial activated carbon A3. However, as the meso pore develops, it can be seen that the total pore volume increases by about 2 times.

Example 2

Preparation of adsorbent for dioxin removal of zeolite material

Prepare zeolite by grinding the zeolite or zeolite of 34 μm or less to 34 μm or less, and mix the prepared zeolite and 1M hydrochloric acid solution at about 82: 18% by weight to maintain about 90 ° C. on a hot plate. After mixing for about 3 hours, the mixture was poured with distilled water, shaken and left to stand to remove the supernatant, and then distilled water was poured and washed 15 times in the same manner. After washing, and dried until the water is completely removed at about 105 ℃ to prepare a dioxin removal adsorbent (C2) of the zeolite material.

Experimental Example 2

BET was measured for the zeolite C1 on the market and the adsorbent C2 for dioxin removal of the zeolite material obtained in Example 2, and the results are shown in Table 2.

absorbent BET Specific surface area [㎡ / g} Pore Volume [cc / g] Median Pore [Å] C1 32.0238 0.098917 108.2544 C2 63.2738 0.134885 63.6853

It can be seen from Table 2 that the specific surface area and pore volume of the dioxins removal adsorbent C2 of the zeolite material obtained in Example 2 are increased by almost twice that of commercial zeolite C1.

Example 3

Preparation of Adsorbent for Dioxin Removal of Activated Carbon and Zeolite Mixture

1. The adsorbent for dioxin removal of activated carbon and zeolite mixture by blending the adsorbent A3-2 for dioxin removal of activated carbon material obtained in Example 1 and the adsorbent C2 for dioxin removal of zeolite material obtained in Example 2 in a weight ratio of 6: 4. (GA-64) was prepared.

2. The adsorbent for dioxin removal of activated carbon and zeolite material by combining the adsorbent A3-2 for dioxin removal of activated carbon material obtained in Example 1 and the adsorbent C2 for dioxin removal of zeolite material obtained in Example 2 at a weight ratio of 5: 5. (GA-55) was prepared.

3. The adsorbent for dioxin removal of activated carbon and zeolite-containing material by blending the adsorbent A3-2 for dioxin removal of activated carbon material obtained in Example 1 and the adsorbent C2 for dioxin removal of zeolite material obtained in Example 2 at a weight ratio of 3: 7. (GA-37) was prepared.

Experimental Example 3

Dioxin adsorption experiments were performed on the adsorbents GA-64, GA-55, and GA-37 for dioxin removal of the activated carbon and zeolite blended material obtained in Example 3, and the results are shown in FIGS. 1 and 2.

As the adsorbed material in the experiment, 1,2-Dichloro-benzene containing benzene ring and chlorine and known as dioxin simulant was used as dioxin, and dioxin of GA-64, GA-55, and GA-37 were used as adsorbents. The adsorption test was carried out using a device consisting of a reactor, an electric heater, a flue gas injector and a vaporizer to be treated.

The material of the reactor used here is quartz, and since 1,2-dichloro benzene exists in a liquid phase at room temperature, the liquid is injected into a saturator, and then nitrogen is regulated by MFC (Mass Flow Controller). Gas was passed through a saturator to obtain a gaseous reaction gas.The concentration of the reactor was wound around a heating band in the saturator, and a thermocouple was installed in the saturator to adjust the temperature of the saturator using a PID controller. The injection concentration of the reactants was adjusted by maintaining and changing. In addition, to prevent the condensation of the entire line (Line) was wound around the heating band (Heating band) to maintain 150 ℃. Adsorption experiments were performed by filling 0.2 g of adsorbent in a U-shaped quartz reactor and flowing a reaction gas. In order to determine the change of the adsorption amount over the reaction time, the released 1,2-Dichlorobenzene was measured by gas chromatography.

It can be seen from FIG. 1 and FIG. 2 that the adsorbent for dioxin removal of the blended material having a high activated carbon content has a long time at which a break point appears and the adsorption amount is also large.

Experimental Example 4

The dioxins and SO ₂ adsorption capacities of the adsorbent GA-64 for dioxin removal of the blended material obtained in Example 3 and the commercially available foreign commercial adsorbent A4 (manufactured by Noritz) are shown in FIGS. 3 to 5.

As can be seen from FIGS. 3 and 4, the foreign commercial adsorbent A4 has almost the same adsorption rate as the dioxin adsorbent GA-64 according to the present invention, but in the case of GA-64, the breakthrough point appears behind the A4. In the temperature-desorption experiment (TPD), the adsorption energy is also moved to high temperature and the saturation adsorption amount is also increased.

In addition, it can be seen from FIG. 5 that the SO ₂ adsorption capacity is remarkably superior to the adsorbent GA-64 according to the present invention compared to foreign commercial adsorbent A4.

Experimental Example 5

A simulation experiment was conducted to determine the applicability of the adsorbent obtained in Example to the actual industrial site. Inflow air flow rate of 2.5Nm3 / min and spray amount of adsorbent 100mg / Figure 6 shows the results of the pilot test while maintaining the differential pressure of the bag filter to 150mmAq or more on the Nm3 scale.

As can be seen in Figure 6, it showed sufficient adsorption efficiency of 96%, 67% for dioxin and SO ₂ , respectively.

The present invention is not limited to the above-described specific preferred embodiments, and various modifications can be made by any person having ordinary skill in the art without departing from the gist of the present invention claimed in the claims. Of course, such changes will fall within the scope of the claims.

As described above, according to the present invention, an adsorbent for dioxin removal using activated carbon and natural zeolite and a method for preparing the adsorbent may provide excellent effects as follows.

According to the activated carbon-based adsorbent and the method for preparing the adsorbent according to the present invention, the surface of the activated carbon can be improved to reduce the risk of explosion at high temperatures.

According to the zeolite-based adsorbent and the method for preparing the adsorbent according to the present invention, the adsorption capacity can be improved by acid treatment of the zeolite having a certain particle size.

According to the present invention, the adsorbent of the blended material in which the adsorbent based on the activated carbon and the adsorbent based on the zeolite are mixed at a predetermined ratio, and the method for preparing the adsorbent has not only an excellent dioxin adsorption capacity but also other harmful acids contained in the exhaust gas. The gas can be removed at the same time.

According to the present invention, it is possible to obtain an adsorbent having excellent adsorption capacity and low cost.

Figure 1 is a graph showing the exhaust concentration of 1,2-DCB over time of the adsorbents (GA-64, GA-55, GA-37) prepared according to an embodiment of the present invention

Figure 2 is a graph showing the temperature desorption test (TPD) results of the adsorbents (GA-64, GA-55, GA-37) prepared according to an embodiment of the present invention

Figure 3 is a graph showing the discharge concentration of 1,2-DCB over time of the adsorbent (GA-64) and the foreign commercial adsorbent prepared according to the embodiment of the present invention

Figure 4 is a graph showing the temperature desorption test (TPD) results of the adsorbent (GA-64) and the foreign commercial adsorbent prepared according to the embodiment of the present invention

5 is a graph showing the adsorption efficiency of the adsorbent (GA-64) prepared in accordance with an embodiment of the present invention and the foreign commercial adsorbent

Figure 6 is a graph showing the simulation results for determining the applicability of the adsorbent obtained in the embodiment of the present invention to the actual industrial site

Claims (9)

A supporting step of combining and processing activated carbon and CaCl ₂ solution; And Method for producing an adsorbent for dioxins removal of activated carbon material, characterized in that it comprises a drying step of drying the supported activated carbon at 120 ~ 200 ℃. The method of claim ₂ , wherein in the supporting step, the activated carbon and CaCl ₂ solution is 80-95: a method for preparing an adsorbent for dioxin removal of activated carbon material, characterized in that blended in 5% by weight.  The method of claim 1, wherein the activated carbon has a particle size of 34 μm or less. An adsorbent for dioxin removal of activated carbon material, which is prepared by the method according to any one of claims 1 to 3. A supporting step of combining and treating zeolite and HCl solution; A washing step of washing the zeolite after the supporting step with water; And Method for producing an adsorbent for dioxins removal of zeolite material, characterized in that it comprises a drying step of drying the washed zeolite until the water is completely removed. The method of claim 5, wherein the zeolite and HCl solution in the compounding step is a method for producing a dioxin adsorbent for removing zeolite material, characterized in that the compounding in a weight percent of 75-85: 15-25. The method of claim 5, wherein the zeolite particle size is less than 34㎛ dioxin removal adsorbent manufacturing method characterized in that the material. An adsorbent for dioxin removal of a zeolite material, which is prepared by the method according to any one of claims 5 to 7. Claims 1 to 3 of the adsorbent for dioxin removal of activated carbon material prepared by the method of any one of claims 1 to 3 and dioxin removal adsorbent of zeolite material prepared by the method of any one of claims 5 to 7. 6: The adsorbent for dioxins removal of the blended material characterized by including in the weight ratio of 4-7.