JP4131417B2 - Method for reducing organochlorine compounds in exhaust gas from cement production facilities - Google Patents

Description

  The present invention relates to a method for reducing organochlorine compounds in exhaust gas from a cement production facility, and more specifically, adsorbs organic chlorinated compounds such as dioxins and PCBs emitted from the cement production facility, decomposes them as fuel, and heat treats them, and the amount of emissions It is related with the technology which can reduce.

Dioxins (PCDDs) are abbreviations of poly chloro dibenzo-p-dioxin and are a kind of organic chlorine compounds. Poly chloro dibenzofuran (PCDFs) is known as an analog of this dioxin.
In particular, it belongs to Tetra chloro dibenzo-p-dioxin, which is a tetrachloride of PCDDs (T4CDDs), and has chlorine at positions 2, 3, 7, 8 3,7,8-T4CDD is highly toxic.
The 2,3,7,8-tetrachloro form is obtained as a by-product in the production of trichlorophenol, 2,4,5-trichlorophenoxyacetic acid, and is obtained by chlorination of dibenzo-P-dioxin. The melting point is 306-307 ° C.

  Further, as another organic chlorine compound that is harmful to the human body, for example, PCB (polychlorinated biphenyl) is known. PCB is excellent in chemical stability, insulation, nonflammability, and adhesiveness, and has been used as an insulating oil for transformers and capacitors mounted in electric facilities such as power plants, railways, and buildings. However, it contains a coplanar PCB that has the same toxicity as dioxin. Therefore, in 1974, the law prohibits the manufacture, distribution and new use of PCBs.

  Examples of the PCB treatment method include an incineration treatment method in which PCB is heat-treated at a high temperature, a dechlorination decomposition method in which PCB is dechlorinated, and a supercritical water in which PCB is decomposed into carbon dioxide and water. A critical hydrolytic decomposition method has been developed. Of these, incineration methods are concerned that dioxins are synthesized when the heat treatment gas of PCB is cooled.

Thus, for example, Patent Document 1 and Patent Document 2 are known as conventional techniques for solving these problems.
Patent Document 1 supplies exhaust gas from a cement production facility to a dust collector, collects dust collection dust containing an organic chlorine compound, and collects at least a part of the collected dust collection dust at 800 ° C. or higher in the cement production facility. This shows a method of putting it in the high temperature part. Since dioxins are thermally decomposed at around 800 ° C., this method can efficiently decompose and detoxify dioxins.
In addition, a small amount of the vaporized organochlorine compound is contained in the dedusted gas discharged from the dust collector and released to the atmosphere from the flue. As a countermeasure against this, Patent Document 1 describes a method of reducing the dioxin concentration in the dedusted gas. This is a method in which exhaust gas is drawn from a point (low temperature part) having a temperature of 30 to 400 ° C. in a cement manufacturing facility and supplied to a dust collector. That is, in the exhaust gas derived from the low temperature part, the organic chlorine compound is concentrated (low temperature concentration) compared to the exhaust gas from the high temperature part of the cement manufacturing facility. As a result, the concentration of dioxins in the dust removal gas decreases if the dust collection dust having a high organochlorine compound concentration is removed by the dust collection treatment.

In Patent Document 2, a PCB-containing material carried from the outside to a cement factory is put into a rotary kiln, and this is heated by heat (1000 ° C. or higher) when firing a cement clinker, and the PCB is thermally decomposed. A method is shown in which exhaust gas generated during pyrolysis is led out of the rotary kiln and then rapidly cooled at a cooling rate of 20 ° C./second or more. By cooling the exhaust gas at 20 ° C./second or more, the exhaust gas passes through a temperature range in which the amount of dioxins synthesized increases in a short time. As a result, PCB can be decomposed while preventing the generation of dioxins.
JP 2004-244308 A JP 2002-147722 A

  Thus, according to Patent Document 1, at least a part of the dust collected by passing the exhaust gas through the dust collector is put into a high temperature part of a cement manufacturing facility that is 800 ° C. or higher during normal operation, and the dust is collected. Dioxins adsorbed by dust were pyrolyzed. At that time, as a measure against organochlorine compounds in the dedusted gas (dust collector passing gas) released from the flue to the atmosphere, the exhaust gas is drawn out from the point where the temperature is 30 to 400 ° C. (low temperature part) in the cement production facility, The method of supplying this to a dust collector was adopted. However, with this measure, dioxins discharged from the cement production facility could not be reduced sufficiently.

  On the other hand, Patent Document 2 is to thermally decompose a PCB-containing material carried from outside (external) of a cement manufacturing facility by heating to 1000 ° C. or higher in a rotary kiln. However, this method could not remove PCB generated in the cement production facility.

Accordingly, as a result of earnest research, the inventor calcined adsorbent powder having an adsorption function of organic chlorine compounds such as coal fine powder, activated carbon fine powder and coke fine powder (including oil coke fine powder) that also serve as fuel. By supplying it into the exhaust gas generated at times, organic chlorine compounds such as dioxins and PCBs contained in the exhaust gas are adsorbed on the adsorbent powder, and then the adsorbent powder containing this organic chlorine compound is collected by a dust collector, If the collected adsorbent powder is used as fuel for firing, the amount of dioxins discharged from the cement production facility and organochlorine compounds such as PCBs can be further reduced, and firing As a result, the present invention has been completed.
Moreover, if a bag filter having a filter cloth with an organochlorine compound decomposition catalyst is used as a dust collector, and if the exhaust gas is a dedusted gas that has passed through the electric dust collector, dioxins and PCBs discharged from the cement production facility, etc. The inventors have found that the amount of organochlorine emissions can be further reduced, and have completed this invention.

This invention can reduce the discharge amount of organic chlorine compounds such as dioxins and PCBs discharged from a cement manufacturing facility, and can reduce the amount of organic chlorine compounds in the exhaust gas of a cement manufacturing facility that can save fuel. It aims to provide a method .

The invention according to claim 1 includes a step of dedusting a preheater exhaust gas containing an organic chlorine compound generated when firing cement clinker from a cement raw material in a rotary kiln in an electric dust collector, Titanium-vanadium from an organic substance adsorption step for adsorbing the organic chlorine compound in the exhaust gas to the adsorbed powder by supplying adsorbed powder to the adsorbed powder, and from 210 ° C to 230 ° C exhaust gas containing the adsorbed powder containing the organic chlorine compound The collection process of collecting the adsorbed powder by a dust collector having a filter cloth with an organic chlorine compound decomposition catalyst, and the collected adsorbed powder as a fuel for burning cement clinker from the combustion burner of the rotary kiln. by supplying the kiln, cement manufacturing set having a decomposing decomposition step of organic chlorine compounds adsorbed on the adsorbent powder Organic chlorine compounds in the exhaust gas is reduced way.

According to the first aspect of the present invention, the adsorbed powder is supplied into the exhaust gas containing the organic chlorine compound generated when the cement clinker is fired. Thereby, organic chlorine compounds, such as dioxins contained in exhaust gas, and PCB, are adsorbed by adsorbent powder (organic substance adsorption process).
Thereafter, the adsorbed powder containing the organic chlorine compound is sucked into the dust collector together with the exhaust gas, and is collected as dust collecting dust here (dust collecting step).
The collected adsorbed powder is sent to the cement clinker firing process, where it is burned as a fuel for firing the cement clinker, and the organochlorine compound adsorbed on the adsorbed powder is thermally decomposed to be detoxified (decomposition process) ). Thereby, the discharge | release amount of organochlorine compounds, such as dioxins and PCB which are discharged | emitted from a cement manufacturing facility, can be reduced more. In addition, fuel for firing can be saved.

The adsorbed powder is not limited as long as it is a powder capable of adsorbing dioxins in exhaust gas and organochlorine compounds such as PCB. However, a porous powder having high adsorptivity of the organic chlorine compound is preferable. For example, coal fine powder, activated carbon fine powder, coke fine powder (including oil coke fine powder) and the like can be employed.
The larger the BET specific surface area, the better the adsorbed powder. If it is less than 0.1 m ² / g, realistic adsorption performance cannot be obtained.

The larger the amount of adsorbed powder supplied to the exhaust gas, the better it is per 1 m ^{3 of} exhaust gas. When it is 200 g / m ³ or more, the burden on the dust collector is extremely increased. Using an adsorbent powder having a large BET specific surface area can reduce the burden on the dust collector.

A method of bringing the adsorbed powder into contact with the exhaust gas is not limited. For example, it is possible to employ an adsorbed powder input machine in which an adsorbed powder input port is connected in the middle of a duct for supplying exhaust gas to a dust collector. As the adsorbed powder feeder, a screw feeder or the like can be employed.
As the dust collector, for example, an electric dust collector or a bag filter can be employed.

As the cement manufacturing facility, for example, a rotary kiln using a firing device can be employed. Moreover, you may employ | adopt what has a preheater, a calcining furnace, a rotary kiln, etc.
The firing temperature of the cement, for example, the temperature in the rotary kiln is usually 1100 to 1450 ° C., which exceeds 700 ° C. of the pyrolysis temperature of the organic chlorine compound. Therefore, the organic chlorine compound is thermally decomposed and detoxified when the cement clinker is fired.
The rotational speed of the rotary kiln is, for example, 1 to 3 rpm.

The dust collector is a bag filter having a filter cloth with an organic chlorine compound decomposing catalyst, the exhaust gas is a dedusting gas passing through the electrostatic precipitator.

Exhaust gas containing organochlorine compounds generated during firing is sucked into an electrostatic precipitator. Some organochlorine compounds remain in the dust removal gas that has passed through the electric dust collector. Therefore, the adsorbed powder is brought into contact with the dedusted gas passing through the flue for opening to the atmosphere. Thereby, organic chlorine compounds, such as dioxins and PCB contained in dedusting gas, are adsorbed by the adsorbent powder.
Thereafter, the adsorbed powder containing the organic chlorine compound is collected by the bag filter together with the dust removal gas. At this time, the filter cloth of the bag filter contains a titanium-vanadium-based organochlorine compound decomposition catalyst. Therefore, the organochlorine compound of the adsorbed powder adhering to the filter cloth comes into contact with the organochlorine compound decomposition catalyst, and is chemically decomposed and rendered harmless.

  Next, the adsorbed powder collected by the bag filter is sent to the cement clinker firing step and used as part of the cement clinker firing fuel. At this time, even if a part of the organochlorine compound adsorbed on the adsorbed powder by contact with the organochlorine compound decomposition catalyst remains in an undecomposed state, the adsorbed powder is used as part of the calcined fuel in this way. Therefore, the undecomposed organochlorine compound is thermally decomposed and made harmless during firing. As a result, it is possible to further reduce the discharge amount of dioxins discharged from the cement manufacturing facility and organochlorine compounds such as PCB.

  As a filter cloth with an organic chlorine compound decomposition catalyst, for example, Remedia (trade name) manufactured by Japan Gore-Tex Co., Ltd. can be employed. In this case, the temperature at which the organochlorine compound decomposition catalyst works most effectively is 210 to 230 ° C.

  The cement clinker is fired using a rotary kiln, and the adsorbed powder is used as a fuel for a combustion burner of the rotary kiln.

By supplying the adsorbed powder containing the organic chlorine compound to the combustion burner as part of the fuel for burning the cement clinker, the organic chlorine compound is thermally decomposed by the heat of burning during the clinker firing. As a result, fuel can be saved, and the amount of dioxins and organic chlorine compounds such as PCBs discharged from the cement manufacturing facility can be further reduced.

The invention according to claim 2 is the method for reducing organochlorine compounds in the exhaust gas of a cement manufacturing facility according to claim 1, wherein the adsorbed powder is at least one of coal fine powder, activated carbon fine powder, and coke fine powder. is there.

The adsorbed powder may be fine coal powder, fine activated carbon powder, or fine coke powder. Also, a combination of two or more of these may be used.
The larger the BET specific surface area of the fine coal powder, the better. If it is less than 0.1 m ² / g, realistic adsorption performance cannot be obtained.
The larger the BET specific surface area of the activated carbon fine powder, the better. If it is less than 0.1 m ² / g, realistic adsorption performance cannot be obtained.
The larger the BET specific surface area of the fine coke powder, the better. If it is less than 0.1 m ² / g, realistic adsorption performance cannot be obtained.

  According to the invention described in claim 1, by supplying the adsorbent powder that also serves as fuel to the exhaust gas generated at the time of firing, the organic chlorine compounds such as dioxins and PCB contained in the exhaust gas are used as the adsorbent powder. The adsorbed powder after adsorption is collected by a dust collector and used as a fuel for firing. Thereby, the organochlorine compound adsorbed by the adsorbed powder is thermally decomposed, and the discharge amount of the organochlorine compound discharged from the cement manufacturing facility can be further reduced. In addition, fuel for firing can be saved.

In particular, if a bag filter using a filter cloth with an organochlorine compound decomposition catalyst is used as a dust collector, and if it is a dedusted gas that has passed through an electric dust collector as an exhaust gas, organic matter such as dioxins and PCBs discharged from cement production facilities The amount of chlorine compound discharged can be further reduced.

  Further, the organochlorine compound is thermally decomposed by the heat of firing at the time of clinker firing by supplying the adsorbent powder containing the organochlorine compound to the combustion burner as part of the fuel for firing the cement clinker. As a result, fuel can be saved, and the amount of dioxins and organic chlorine compounds such as PCBs discharged from the cement manufacturing facility can be further reduced.

  Examples of the present invention will be specifically described below.

  In FIG. 1, reference numeral 10 denotes a cement firing facility to which a method for reducing organochlorine compounds in exhaust gas from a cement production facility according to Embodiment 1 of the present invention is applied. The cement firing facility 10 includes a raw material process unit for pulverizing a cement raw material and a firing process unit for firing the pulverized cement raw material.

  The raw material process section includes a raw material storage 11 that individually stores limestone, clay, silica, and iron raw materials as cement raw materials, and a raw material dryer 12 that heats and drys some cement raw materials having a high water content such as clay, for example. The raw material mill 13 for pulverizing the cement raw material, the electric dust collector B1 for collecting the dust containing the organic chlorine compounds discharged from the raw material dryer 12 and the raw material mill 13, and the cement raw material pulverized by the raw material mill 13 are temporarily stored. And a storage silo 14.

  The cement raw material stored in the raw material storage 11 is put into the rotating drum of the raw material mill 13 through the raw material transporting equipment 118. However, a part of the cement raw material having a high water content is supplied to the raw material dryer 12 through the water-containing raw material supply facility 131. This part of the cement raw material is heated and dried here, and then fed into the raw material mill 13 through the dry raw material discharge facility 132. High temperature exhaust gas is supplied to the raw material dryer 12 and the raw material mill 13 through an exhaust gas duct 21 from an upper portion of a preheater 16 described later. Therefore, the internal temperature of the raw material dryer 12 is about 300 ° C., and the internal temperature of the raw material mill 13 is about 200 ° C. A fan F <b> 1 is provided upstream of the exhaust gas duct 21. A large number of metal balls are accommodated in the rotating drum of the raw material mill 13. By continuously feeding the cement raw material while rotating the rotating drum, the cement raw material is pulverized to about 90 μm or less. The crushed cement raw material is input to the storage silo 14 through the pulverized raw material transport facility 121.

The raw material dryer 12 and the raw material mill 13 are connected to each end portion of the upstream side portion of the flue 129 that opens the exhaust gas from the inside through the chimney 130 to the atmosphere. In the middle of the downstream side portion of the flue 129, an electric dust collector (dust collector) B1 for collecting adsorbed powder is provided. The dust collection dust containing the organic chlorine compound collected by the electric dust collector B <b> 1 is inserted into the pulverized raw material transport facility 121 through the dust discharge pipe 123. Therefore, the dust collection dust containing the organic chlorine compound is finally stored in the storage silo 14.
Further, a bag filter (dust collector) B2 having a filter cloth 160 is provided in a portion of the flue 129 between the electric dust collector B1 and the chimney 130. Details of the bug filter B2 will be described later. In the portion of the flue 129 between the electrostatic precipitator B1 and the bag filter B2, there is an adsorbed powder inlet 150 for adsorbing the organic chlorine compound in the exhaust gas generated during firing (exhaust gas from the top of the preheater 16). Is provided.

As the adsorbed powder, fine coal powder having a particle size of 20 to 70 μm that also serves as a fuel for firing cement clinker from cement raw material is employed. Instead of coal fine powder, activated carbon fine powder of 10 to 100 μm may be adopted. The amount of adsorbed powder introduced from the inlet 150 is 100 g per 1 m ^{3 of} exhaust gas. Further, a fan F2 is provided on the raw material mill 13 side of the upstream side portion of the flue 129 that is bifurcated. Further, in the flue 129, a fan F3 is provided between the bag filter B2 and the chimney 130. Further, the adsorbed powder transport facility 30 is installed so as to supply the harmless adsorbed powder discharged from the bag filter B <b> 2 to the combustion burner 17. The bag filter B2 and a fuel inlet of the combustion burner 17 to be described later are disposed on the combustion burner 17 with adsorbed powder containing an organic chlorine compound collected by a filter cloth 160 and rendered harmless by a decomposition reaction by an organic chlorine compound decomposition catalyst. The adsorbed powder delivery pipe 30 is inserted.

Next, the filter cloth 160 of the bag filter B2 will be described in detail with reference to FIG.
As shown in FIG. 2, the bag filter B2 has a bag-like filter cloth 160 with an organochlorine compound decomposition catalyst. The filter cloth 160 is a felt made of PTFE (drawn polytetrafluoroethylene) fiber. On the front side of the filter cloth 160, a membrane filter 161 having a predetermined thickness impregnated with an organic chlorine compound decomposition catalyst is laminated. The bag filter B2 has a processing air volume of 1120 m ³ N / h, a filtration area of 24 m ² , a filtration rate of 1.15 m / min (max), and an internal temperature of 220 ° C.
As the organic chlorine compound decomposition catalyst, a titanium-vanadium system capable of decomposing an organic chlorine compound is employed. When the adsorbed powder adheres to the filter cloth 160, the organic chlorine compound contained in the adsorbed powder comes into contact with the organic chlorine compound decomposition catalyst, and the organic chlorine compound is decomposed by the decomposition action of the organic chlorine compound decomposition catalyst to make it harmless. To do.

  The firing process section includes a preheater 16 having a five-stage cyclone 15 for heating the cement raw material from the storage silo 14 to a high temperature (850 ° C.), and a lowermost stage section of the preheater 16 connected to the kiln bottom. A dry rotary kiln 18 having a combustion burner 17 at the front, a clinker cooler 19 for cooling the cement clinker discharged from before the kiln of the rotary kiln 18, a clinker silo (not shown) for temporarily storing the obtained cement clinker, And a second dust collector (not shown) that collects dust discharged from the clinker silo.

The preheater 16 descends while passing through the upper and lower cyclones 15 sequentially from the upper side so that the pulverized raw material charged from the storage silo 14 is easily fired in the rotary kiln 18 through the raw material powder transporting facility 165. Gradually preheat to a predetermined temperature (900 ° C.).
A rotary kiln 18 that produces cement clinker at 100 t / h is employed. The rotary kiln 18 has a kiln shell lined with a refractory, and the cement clinker is fired from the cement raw material by the heat of the flame from the combustion burner 17 fueled with heavy oil or fine coal.

Next, the organic chlorine compound reduction method in the exhaust gas performed in the cement production facility 10 of Example 1 (inside the system) will be described.
As shown in FIG. 1, each cement raw material in the raw material storage 11 is put into the raw material mill 13 through the raw material transport facility 118. However, only a part of the cement raw material having a high water content is supplied to the raw material dryer 12 through the water-containing raw material supply facility 131. This part of the cement raw material is heated and dried in the raw material dryer 12 and then fed into the raw material mill 13 through the dry raw material discharge facility 132. In the raw material mill 13, the cement raw material is pulverized to a particle size of approximately 90 μm or less together with the dry raw material from the raw material dryer 12 by a large number of metal balls. The pulverized cement raw material is fed into the storage silo 14 through the pulverized raw material transport facility 121.
High temperature exhaust gas is supplied to the raw material dryer 12 and the raw material mill 13 from above the preheater 16 through the exhaust gas duct 21. Therefore, the internal temperature of the raw material dryer 12 is about 300 ° C., and the internal temperature of the raw material mill 13 is about 100 to 200 ° C.

  In recent cement manufacturing facilities 10, organic chlorinated compounds such as dioxins and PCBs, and other wastes (such as municipal waste and incinerated ash) containing organic substances and chlorine are mixed as part of cement raw materials (for example, clay). ing. At that time, as described above, since the interiors of the raw material dryer 12 and the raw material mill 13 are heated to around 300 ° C., the organic chlorine compounds (mainly dioxins) are vaporized therein. Dust contained in the exhaust gas is collected by the electric dust collector (dust collector) B1, and the dust collected passes through the dust discharge pipe 123 and the pulverized raw material transport equipment 121 in this order, and is supplied to the storage silo 14.

The cement raw material stored in the storage silo 14 is then supplied to the firing process section. That is, the pulverized cement raw material is supplied to the upper part of the preheater 16 via the raw material powder transport facility 165. The pulverized raw material is finally preheated to 800 ° C. while descending each cyclone 15 in order. The obtained preheating raw material (cement raw material) is put into the kiln bottom of the rotary kiln 18.
Here, the preheating raw material is fired into a cement clinker by heating at 1100 to 1450 ° C. using a combustion burner 17 while rotating in the kiln shell. The obtained cement clinker falls to the clinker cooler 19 from the end in front of the kiln and is cooled here.

On the other hand, adsorbed powder made of fine coal powder is introduced into the dedusted gas that has passed through the dust collector B1 at 100 g per 1 m ^{3 of} exhaust gas (dedusted gas) from the adsorbed powder inlet 150 provided in the flue 129. Is done. Thereby, organic chlorine compounds such as dioxins and PCB slightly contained in the dust removal gas are adsorbed to the adsorbed powder.
Thereafter, the adsorbed powder containing the organic chlorine compound is sucked into the bag filter B2 having an internal temperature of 220 ° C. together with the dust removal gas at a treatment air volume of 1120 m ³ N / h. The adsorbed powder sucked into the bag filter B2 is filtered while attached to the membrane filter 161 with the organochlorine compound decomposition catalyst laminated on the front side of the filter cloth 160 (FIG. 2). At this time, the filtration rate of the adsorbed powder is 1.15 m / min (max). The clean dedusted gas that has passed through the bag filter B2 is released from the downstream portion of the flue 129 through the chimney 130 to the atmosphere.

  The organochlorine compound (such as dioxin) in adsorbed powder adhering to the membrane filter 161 comes into contact with a titanium-vanadium-based organochlorine compound decomposition catalyst, and is chemically decomposed and rendered harmless by the decomposition action of this catalyst. Thereafter, the adsorbed powder collected by the bag filter B2 is sent to the fuel inlet of the combustion burner 17 through the adsorbed powder delivery pipe 30, where it is used as part of the fuel for burning the cement clinker. At this time, even if a part of the organochlorine compound adsorbed to the adsorbed powder by contact with the organochlorine compound decomposition catalyst remains in an undecomposed state, the adsorbed powder is used as part of the calcined fuel. The undecomposed organochlorine compound is thermally decomposed and detoxified during firing. As a result, the amount of dioxins discharged from the cement manufacturing facility 10 and organic chlorine compounds such as PCBs can be further reduced.

Thus, here, by supplying a predetermined amount of adsorbed powder that also serves as fuel into the dust removal gas that has passed through the electric dust collector B1, dioxins and organochlorine compounds such as PCBs that are slightly contained in the dust removal gas Is adsorbed by the adsorbent powder, and then the adsorbed powder is collected by the bag filter B2 and used as a fuel for firing. Thereby, the organochlorine compound adsorbed on the adsorbed powder is thermally decomposed and rendered harmless. As a result, the amount of dioxins discharged from the cement manufacturing facility 10 and organic chlorine compounds such as PCBs can be further reduced as compared with the conventional method.
Further, since the adsorbed powder containing the organic chlorine compound is supplied to the combustion burner 17 as a part of the fuel for burning the cement clinker, the organic chlorine compound can be thermally decomposed by the heat of firing during the clinker firing. In addition, the burning fuel can be saved.

Next, with reference to FIG. 3, the organic chlorine compound reduction method in the waste gas of the cement manufacturing facility which concerns on the reference example of this invention is demonstrated.
As shown in FIG. 3, the cement manufacturing facility 10A to which the organic chlorine compound reducing method in the exhaust gas of the cement manufacturing facility of the reference example is applied omits the bag filter B2, and the adsorbed powder inlet 150 is connected to the flue 129. Among these, it is characterized in that it is formed immediately before the electric dust collector B1.
Thereby, each exhaust gas from the raw material dryer 12 and the raw material mill 13 is mixed with adsorbed powder from the inlet 150 immediately before being sucked into the electric dust collector B1 through the flue 129, and the organic chlorine compound in the exhaust gas is adsorbed into the adsorbed powder. To be adsorbed.
Thereafter, the adsorbed powder containing the organic chlorine compound is collected by the electric dust collector B1. And the dust collection dust discharged | emitted from electric dust collector B1 passes the dust discharge pipe 123 and the grinding | pulverization raw material transport equipment 121 in order, and is supplied to the storage silo 14. FIG.

In this way, by supplying the adsorbed powder to the exhaust gas generated during firing, the organic chlorine compound contained in the exhaust gas is adsorbed to the adsorbed powder, and the adsorbed powder is collected by the electric dust collector B1 to be used at the time of firing. Since the fuel is used, the amount of dioxins and organic chlorine compounds such as PCBs discharged from the cement manufacturing facility 10A can be reduced as compared with the conventional method. In addition, fuel for firing can be saved.
Other configurations, operations, and effects are within a range that can be estimated from the first embodiment, and thus description thereof is omitted.

Here, with reference to the graph of FIG. 4, the result of investigating the relationship between the inlet gas temperature of the bag filter B2 and the PCBs reduction rate using the cement manufacturing facility 10 according to Example 1 of the present invention is reported. To do.
As can be seen from FIG. 4, when the inlet gas temperature of the bag filter B2 is 210 to 230 ° C., the PCBs reduction rate is higher than that at other temperatures. Depending on the type of organochlorine compound decomposition catalyst, the temperature at which the PCBs reduction rate increases may be different from the above temperature.

Separately from this, the amount of PCB in the exhaust gas of the bag filter and the PCB in the exhaust gas of the electrostatic precipitator when the bag filter having the filter cloth with the organochlorine compound decomposition catalyst of Example 1 and the electric dust collector are used. Amount of PCB (Test Example 1), amount of PCB in the exhaust gas of the bag filter when using a bag filter using an existing filter cloth not containing an organic chlorine compound decomposition catalyst, and an electrostatic precipitator / exhaust gas of the electrostatic precipitator The result of comparison with the value of the amount of PCB (Comparative Example 1) is reported.
That is, in Test Example 1, the amount of PCB in the exhaust gas of the bag filter / the amount of PCB in the exhaust gas of the electrostatic precipitator was 0.05. In Comparative Example 1, it was 0.12. Thus, it was found that the amount of PCB was reduced in Test Example 1 having a bag filter with an organochlorine compound decomposition catalyst compared to Comparative Example 1 having no bag filter.

It is a schematic block diagram of the cement baking equipment to which the organochlorine compound reduction method in the waste gas of the cement manufacturing equipment concerning Example 1 of this invention was applied. It is a principal part expanded sectional view of the filter cloth of the bag filter of the cement baking equipment to which the organochlorine compound reduction method in the exhaust gas of the cement manufacturing equipment concerning Example 1 of this invention was applied. It is a principal part schematic block diagram of the cement baking equipment to which the organochlorine compound reduction method in the waste gas of the cement manufacturing equipment concerning the reference example of this invention was applied. It is a graph which shows the relationship between the entrance gas temperature of the bag filter which concerns on Example 1 of this invention, and the reduction rate of PCBs.

Explanation of symbols

10, 10A Cement production equipment,
17 Combustion burner,
18 Rotary kiln,
B1 Electric dust collector (dust collector),
B2 Bag filter (dust collector).

Claims (2)

Dedusting preheater exhaust gas containing organochlorine compounds generated when firing cement clinker from cement raw material in a rotary kiln in an electric dust collector;
An organic matter adsorption process for adsorbing organochlorine compounds in the exhaust gas to the adsorbed powder by supplying adsorbed powder into the exhaust gas after dedusting;
A collection step of collecting the adsorbed powder from an exhaust gas at 210 ° C. to 230 ° C. containing the adsorbed powder containing the organochlorine compound by a dust collector having a filter cloth with a titanium-vanadium organochlorine compound decomposition catalyst; ,
Cement production with a decomposing step of decomposing organochlorine compounds adsorbed on the adsorbed powder by supplying the collected adsorbed powder to a rotary kiln as a fuel for burning the cement clinker from the combustion burner of the rotary kiln Method for reducing organochlorine compounds in exhaust gas from facilities. The method for reducing organochlorine compounds in exhaust gas from a cement production facility according to claim 1, wherein the adsorbed powder is at least one of fine coal powder, fine activated carbon powder, and fine coke powder.

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