KR200347282Y1 - The apparatus for removal of dioxins/furans and heavy metals in the fly ash formed from wastes incinerator - Google Patents

Abstract

The present invention prevents melting of chloride contained in fly ash and consequently fusion to the container of chloride in the removal of dioxins and heavy metals by heating the fly ash generated from the waste incinerator, thereby efficiently and economically removing the dioxins and heavy metals. A heating apparatus 10 for heating a fly ash mixture to a temperature of 550-750 degreeC; A catalytic combustion furnace (20) connected to the heating furnace (10) through a first communication passage (15) and having a dioxin removal catalyst (22) embedded therein; An activated carbon adsorption tower (30) connected to the catalytic combustion furnace (20) through a second communication path (25) for adsorbing and removing a small amount of dioxins and heavy metals remaining in the exhaust gas; As a vacuum pump 40 connected to the activated carbon adsorption tower 30, a vacuum pump for sucking the exhaust gas from the heating furnace 10 through the catalytic combustion furnace 20 and the activated carbon adsorption tower 30 to exhaust to the outside ( 40), wherein the heating furnace 10 is charged with a plurality of charging containers 11 filled with the fly ash mixture to a height of less than 10 cm, the first and second communication passages (15, 25) is a cooling water It is characterized in that it is installed to penetrate the filled cooling chamber (16, 26).

Description

The apparatus for removal of dioxins and heavy metals in the fly ash formed from wastes incinerator}

The present invention relates to the field of waste treatment, and more particularly, in the removal of dioxins and heavy metals by heating the fly ash generated in the waste incinerator, melting of the chloride contained in the fly ash and thus fusion to the container of the chloride. To prevent and efficiently and economically remove dioxins and heavy metals.

As is widely known, garbage is incinerated in an incinerator after a process such as sorting and crushing, and in the process of incineration, a large amount of dioxin, a hazardous substance, is discharged. Only 10-20% of this dioxin is released into the atmosphere, most of which is adsorbed by incineration or fly ash.

In particular, fly ash is known to exist in the form of fine particles containing a lot of chloride, which makes it difficult to remove dioxins and heavy metals contained therein. The fly ash is heated to about 500 ° C. or higher in air to simultaneously remove volatilization of dioxins and heavy metals. If desired, the chloride contained in the fly ash melts and fuses to the vessel containing the fly ash, which renders it impossible to reuse the vessel and reduces the removal efficiency of the dioxins or heavy metals.

On the other hand, a method of heat-treating fly ash at a relatively low temperature has been proposed in the related art, and representative examples thereof are the volatilization and catalytic combustion method and the Hagenmier method.

In the volatilization and catalytic combustion method, hot air at about 400 ° C. is blown to fly ash to volatilize dioxins and heavy metals in fly ash, while volatilized dioxins and vaporized metals are removed by a catalyst and activated carbon in the latter stage.

This 'volatilization and catalytic combustion method' has solved the problem of the container fusion of chloride to some extent, but has a problem that the dioxin and heavy metal content in the treated fly ash is relatively high because the volatilization of dioxins and heavy metals at a relatively low temperature.

The Hagenmier method is a method of pyrolyzing dioxins by heating fly ash at a low temperature of about 350 ° C. in a vacuum or nitrogen atmosphere. This method has a problem in that the pyrolysis time of dioxins is long and the removal of heavy metals is impossible.

In addition, conventionally, alumina cement and Na ₃ PO ₄ are mixed at 10% by weight and 8% by weight with respect to fly ash, and the mixture is compression-molded at an ultrahigh pressure of 1000 kg / cm ² in formwork to form the pellets. After fixing the heavy metal in the heating method, it has been proposed to pyrolyze and remove the dioxins in the pellet by heating to a temperature of about 700 ℃.

However, this method is difficult to automate, construction cost and operation cost is too large has had a problem that the practicality is greatly reduced.

Accordingly, an object of the present invention is to provide a heating furnace capable of heat treating fly ash at a high temperature without fusion in a container of chloride, while simultaneously removing dioxins and heavy metals in the fly ash, and dioxins volatilized by the heat treatment. It is to provide a fly ash processing apparatus that can remove the heavy metal precisely at the rear of the furnace.

1 is a flow chart showing a fly ash processing method according to the present invention.

Fig. 2 is a schematic diagram showing a waste incineration system as a whole, wherein a fly ash processing apparatus according to the present invention is provided downstream of the incineration system.

Figure 3 is a schematic cross-sectional view showing a fly ash processing apparatus of the present invention.

Figure 4 is a view showing a state in which the charging container filled with the fly ash mixture in Figure 2 fly ash processing apparatus.

Figure 5 is a photograph showing the photographing by taking a digital camera of the fly ash mixture as a by-product after the fly ash processing is completed according to the present invention.

In order to achieve the above object, the present invention, as shown in Figure 1, provides a method for the treatment of fly ash for the removal of dioxin and heavy metals, the treatment method, soil, A first step (S10) of mixing a mixture of one or more mixtures selected from the group consisting of waste concrete powder and waste cement powder to 20 to 80% by weight of the total weight; A second step (S20) of filling the plurality of powdered fly ash mixtures mixed in the first step to a height of less than 10 cm in each of the charging containers, and then charging the plurality of charging containers into a heating furnace; A third step (S30) of heating the fly ash mixture in the plurality of charging containers to 550-750 ° C. to volatilize the dioxins and heavy metals contained in the fly ash mixture in the heating furnace; And a fourth step (S40) of discharging the dioxins and heavy metals volatilized in the third step to the outside of the heating furnace together with the exhaust gas.

At this time, when the mixing amount of the mixture is less than 20% by weight, fusion of chloride is found in the charging container in the heating furnace, and when the mixing amount of the mixture exceeds 80% by weight, the amount of fly ash treated is too large. Less problems arise.

In addition, when the height of the fly ash mixture filled in the charging container is more than 10cm, due to the low thermal conductivity of the fly ash is not sufficiently heat treatment to the inside of the fly ash mixture, the removal efficiency of dioxins and heavy metals is significantly reduced.

On the other hand, the mixture is one, or a mixture of one or more selected from the group consisting of soil, waste concrete powder, waste cement powder, it is preferable to filter through a 1.18mm size body.

In addition, the exhaust gas discharged in the fourth step (S40) is exhausted to the outside through the catalytic combustion furnace and the activated carbon adsorption column continuously connected to the heating furnace, the catalyst combustion furnace is built in itself under a temperature of 300 ~ 400 ℃ It is preferable that the dioxins in the exhaust gas are removed by the action of the dioxins removal catalyst, and in the activated carbon adsorption column, trace amounts of dioxins and heavy metals remaining in the exhaust gas are adsorbed.

At this time, when the treatment temperature to the catalytic combustion is less than 300 ℃, the dioxin removal amount of the exhaust gas is significantly reduced, when the treatment temperature to the catalytic combustion exceeds 400 ℃, dioxins due to thermal fatigue phenomenon Shortening the life of the catalyst is caused.

The present invention also provides an apparatus for treating fly ash for removal of dioxins and heavy metals, the apparatus comprising: a heating furnace for heating the fly ash mixture to a temperature of 550 to 750 ° C; A catalytic combustion furnace connected to the heating furnace via a first communication passage and having a dioxin removal catalyst embedded therein; An activated carbon adsorption tower connected to the catalytic combustion via a second communication path to adsorb and remove trace amounts of dioxins and heavy metals remaining in the exhaust gas; A vacuum pump connected to the activated carbon adsorption tower, comprising a vacuum pump for sucking the exhaust gas from the heating furnace through the catalytic combustion furnace and the activated carbon adsorption tower and exhausting the exhaust gas to the outside. A plurality of charging containers to be filled is charged, characterized in that the first and second communication passages are installed to pass through the cooling chamber filled with the cooling water.

Here, the heating furnace is to be opened and closed by a charging door provided at the lower end, the plurality of charging vessel is charged from the bottom up, the first and second communication passage is exhaust gas flowing there It is preferable that the cooling chamber is provided in the form of a coil so as to be sufficiently cooled.

Now, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a system diagram showing the waste incineration system B, and a fly ash processing apparatus 1 is provided downstream of the incineration system B. As shown in FIG.

As shown in FIG. 2, the sorted and crushed waste is charged to the waste incinerator B1 through an input hopper, and the waste charged to the incinerator B1 is incinerated by high heat. The bottom ash generated by incineration is discharged to the bottom ash bunker B3 through the bottom ash discharge device B2.

Meanwhile, the waste gas generated by incineration of waste is gas cooling tower (B4), air preheater (B5), semi-dry reaction tower (B6), bag filter (B7), SCR catalyst tower (B8), heat exchanger (B9), and induction After passing through the blower (B10) continuously is discharged to the outside through the chimney (B11).

At this time, the fly ash (f) containing a large amount of heavy metals and dioxins is discharged from the semi-dry reaction tower (B6) and / or bag filter (B7). In this case, reference numerals B12 and B13, which are not described in FIG. 2, represent the slaked lime reservoir and the duct burner, respectively.

The fly ash (f) is preferably treated by the fly ash treatment device 1 according to the present invention while being mixed with a mixture (a) selected from soil, waste concrete powder or waste cement powder. Best illustrated.

As shown in FIG. 3, the fly ash treatment apparatus 1 of the present embodiment includes a heating furnace 10, a catalytic combustion furnace 20, an activated carbon adsorption tower 30, and a vacuum pump 40. . In addition, first and second communication paths 15 and 25 are provided between the heating furnace 10 and the catalytic combustion furnace 20, and between the catalytic combustion furnace 20 and the activated carbon adsorption tower 30. The first and second communication paths 15 and 25 are respectively surrounded by cooling chambers 16 and 26 filled with cooling water.

The heating furnace 10 of the present embodiment is an electric furnace for heating the fly ash mixture, which will be described in detail below, at a temperature of about 550 to 750 ° C., in which a plurality of charging containers 11 mount the charging containers 11 through a layer layer. It is allowed to be charged while mounted on the shelf 12. At this time, the charging container 11 is made of a stainless material, preferably SUS 316L material, the charging door 13 of the heating door 10 of the heating door 10 with a layer layer stacked on top of the charging door 13 It is charged into the furnace 10 by closing at the bottom (see FIG. 4).

In addition, the catalytic combustion furnace 20 receives the exhaust gas from the heating furnace through the first communication passage 15 and removes dioxins and heavy metals in the exhaust gas. In addition to forming a heat insulating structure by), a lattice-shaped dioxin removal catalyst 22 is formed to correspond to the path of the exhaust gas.

At this time, the first communication path 15 is provided in the form of a coil and is surrounded by the first cooling chamber 16 containing the cooling water. The coil form greatly increases the cooling efficiency of the exhaust gas. In addition, the first cooling chamber 16 is provided with an inlet and an outlet through which the coolant is introduced and discharged, respectively, the inlet and the outlet of which can be closed by a normal on-off valve as well as means for circulating the coolant. It may be connected.

On the other hand, the activated carbon adsorption tower 30 is connected to the catalytic combustion furnace 20 through the second communication passage 25, the inside of the adsorption of heavy metals and dioxins in the unburned exhaust gas from the catalytic combustion furnace 20 Activated carbon is removed.

At this time, the second communication path 25 described above also forms a coil like the first communication path 15 described above, and is surrounded by the second cooling chamber 26 containing the cooling water. Here, the function and structure of the second cooling chamber 26 have the same structure and function as the above-mentioned first cooling chamber 16, and thus description thereof is omitted.

In addition, the upper end of the activated carbon adsorption tower 30 is provided with a vacuum pump 40 for sucking the exhaust gas through the catalytic combustion furnace 20 and the activated carbon adsorption tower 30 from the heating furnace 10 to exhaust to the outside, The vacuum pump 40 is subjected to a negative pressure in the heating furnace 10, the catalytic combustion furnace 20 and the activated carbon adsorption tower 30 to more strictly control the escape of harmful substances to the outside.

Now, a fly ash processing method using the fly ash processing apparatus 1 described above will be described in detail for each step shown in FIG. 1.

<First step; Mixing Step (S10)>

First, the ordinary soil was sieved to an aggregate of # 16 (eye size 1.18 mm) to prepare a powdery mixture having a particle size of less than 1.18 mm.

In addition, the heavy metal concentration and dioxin residual concentration of fly ash discharged from the incineration plant were measured. In this example, the residual dioxin concentration of fly ash was 562.4 pg-iTEQ / g and the heavy metals in fly ash were Pb 67.6ppm, Cd 0.1ppm, 0.5 ppm of Cu, 0.0013 ppm of As, and 0.001 ppm of Hg were detected.

Thereafter, the prepared mixture and the fly ash were mixed with each other to prepare a fly ash mixture, with the mixing ratio of the mixture to the total weight of the fly ash mixture being 28% by weight.

<Second step; Charging step (S20)>

The fly ash mixture obtained in the first step was filled with a plurality of charging containers made of SUS 316L, each having a height of 5 cm, and then charged into the heating furnace (electric furnace) of an oxidizing atmosphere with a plurality of layered layers.

<Third step; Heating stage (S30)>

The temperature in the furnace is raised to 700 ° C. under atmospheric pressure and then maintained at that temperature for about 30 minutes to heat the fly ash mixture filled in the charging vessel.

Here, since the boiling point of dioxins is 315-537 degreeC, the dioxins contained in a fly ash mixture mostly volatilize.

<Fourth step; Removal of Dioxin and Heavy Metals in Exhaust and Exhaust Gas (S40)>

After completing the third step, the vacuum pump is operated to suck the exhaust gas in the furnace to the rear end of the upper portion.

At this time, the exhaust gas flows along the first communication path toward the catalytic combustion furnace, and in the course of the flow, the exhaust gas is cooled by a cooling chamber around the first communication path, which serves to prevent resynthesis of dioxins.

In the present embodiment, the catalytic combustion furnace is maintained at about 350 ℃, dioxin remaining in the exhaust gas is burned by the dioxin removal catalyst in the catalytic combustion furnace, while the lead is highly volatile by the holding temperature of the catalytic combustion furnace Heavy metals such as arsenic, cadmium and mercury are removed.

The exhaust gas that has passed through the catalytic combustion furnace flows into the activated carbon adsorption tower by the vacuum pump, and in the activated carbon adsorption tower, trace amounts of dioxins and heavy metals remaining in the exhaust gas are adsorbed onto the activated carbon.

<Test Example>

After the fourth step was completed, a fly ash was opened to collect the fly ash mixture, and the residual concentration of dioxins and heavy metals in the fly ash mixture was measured.

Table 1 below shows the residual concentration of dioxins measured before and after heating the fly ash mixture to 700 ° C., and the concentration of dioxins in the atmosphere exhausted through the fourth step described above.

Heating temperature (℃) Heating time (minutes) Dioxin concentration in fly ash (pg-iTEQ / g) % Removal Atmospheric concentration (pg-iTEQ / Sm ³ Remarks 700 30 Before heating After heating 100 0.007 Dioxin allowable concentration in German farmland5 pg-iTEQ / g 562.4 0

Table 2 below shows the residual concentration of heavy metals measured before and after heating the fly ash mixture to 700 ° C.

Item Pb (ppm) Cr (ppm) Cd (ppm) Cu (ppm) As (ppm) Hg (ppm) Residual concentration in fly ash before heating 67.6 0 0.1 0.5 1.5 0.005 Residual concentration in fly ash mixture after heating 0.005 0 0.1 0.02 0.0006 0

From the results of Table 1 and Table 2, it was found that the fly ash treatment method of this example removes a large amount of heavy metals and dioxins contained in the fly ash.

On the other hand, Figure 4 is a photographic picture taken with a digital camera by opening the heating furnace in the state completed to the fourth step of the above-described embodiment, through Figure 4, through the fly ash mixture treated in accordance with the present embodiment through the chloride It can be seen that no fusion due to melting of was found.

As described above, the present invention can remove dioxins and heavy metals from fly ash without fusion of chloride to the charging container, and the removal efficiency thereof is much superior to conventional fly ash processing methods and fly ash processing apparatus.

In addition, the present invention has the effect of removing most of the heavy metals and dioxins in fly ash by a simple heat treatment and at the same time can also greatly remove the heavy metals and dioxins contained in the exhaust gas by the heat treatment.

The present invention has the advantage of being able to remove heavy metals and dioxins in fly ash in a simple and inexpensive manner and automate the whole process.

Claims (2)

A heating furnace 10 for heating the fly ash mixture to a temperature of 550 to 750 ° C; A catalytic combustion furnace (20) connected to the heating furnace (10) through a first communication passage (15) and having a dioxin removal catalyst (22) embedded therein; An activated carbon adsorption tower (30) connected to the catalytic combustion furnace (20) through a second communication path (25) for adsorbing and removing a small amount of dioxins and heavy metals remaining in the exhaust gas; As a vacuum pump 40 connected to the activated carbon adsorption tower 30, a vacuum pump for sucking the exhaust gas from the heating furnace 10 through the catalytic combustion furnace 20 and the activated carbon adsorption tower 30 to exhaust to the outside ( 40), The heating furnace 10 is charged with a plurality of charging container 11 is filled with a fly ash mixture to a height of less than 10cm, The first and second communication paths (15, 25) are disposed so as to pass through the cooling chamber (16, 26) filled with the cooling water, apparatus for treating fly ash for removal of dioxin and heavy metals. The method of claim 1, The heating furnace 10 is to be opened and closed by a charging door 13 provided at its lower end, the plurality of charging containers 11 is charged in a state in which the layers are arranged from the bottom up, The first and second communication paths (15, 25) is provided in the form of a coil so that the exhaust gas flowing there is sufficiently cooled by the cooling chamber (26, 26) for the removal of dioxin and heavy metals Fly ash treatment device.