JP4075916B2 - Cement production facility and method for reducing organochlorine compounds in cement production facility - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a cement manufacturing facility and a method for reducing organochlorine compounds in a cement manufacturing facility, and more particularly, to a technology capable of heat treating dioxins and PCBs such as PCBs discharged from a cement manufacturing facility and reducing the discharge amount. .

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. Examples of the exhaust gas from the cement production facility include exhaust gas from a raw material dryer (raw material process part) for drying cement raw material, exhaust gas from a raw material mill (raw material process part) for crushing cement raw material, and the like.

  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. In other words, all the cement raw materials containing organochlorine compounds were fed into the raw material dryer and the raw material mill with the exhaust gas discharged from the upper part of the preheater as the heat source, and the internal temperature was around 300 ° C. It was converted. Therefore, the exhaust gas (especially dust) from a raw material mill etc. contained an organic chlorine compound.

  On the other hand, the cement raw material pulverized by the raw material mill is continuously fed into the upper part of the preheater. At this time, most of the organic chlorine compounds adhering to the cement raw material are not thermally decomposed as the cement raw material descends in the preheater as set in advance, and the heat of the upper part of the preheater (including the heat of exhaust gas) The gas was vaporized (separated) by the gas, mixed into the exhaust gas as it was, and returned to the raw material mill. As a result, organochlorine compounds were circulated in the raw material process for cement production, and the concentration was gradually increased. As a result, the amount of dioxins discharged from the cement production facility has increased.

  Patent Document 2 discloses that a PCB-containing material carried from outside (external) of a cement manufacturing facility is heated to 1000 ° C. or higher in a rotary kiln to be thermally decomposed. However, this method could not remove PCB generated in the cement production facility.

  As a result of intensive studies, the inventor has paid attention to the cause of dioxins and PCBs being generated from organic chlorine compounds (chlorine content) contained in cement raw materials. That is, if the cement raw material containing the organic chlorine compound is heated by the organic substance remover before the cement raw material containing the organic chlorine compound is put on the top of the preheater and heated to around 300 ° C., an organic chlorine compound such as a dioxin precursor is obtained. It can be separated or decomposed from the cement raw material just before preheating by the preheater. In addition, the heat treatment gas containing the organic chlorine compound generated by the heat treatment in the organic substance remover is supplied to a high temperature part at 800 ° C. or higher during normal operation in the cement manufacturing facility, thereby removing the organic chlorine compound in the heat treatment gas. It can be pyrolyzed. As a result, the inventors have found that the amount of dioxins discharged from cement production facilities and the amount of organochlorine compounds such as PCBs can be reduced as compared with the conventional one, and completed the present invention.

  It is an object of the present invention to provide a cement production facility capable of reducing the discharge amount of dioxins and PCBs and other organic chlorine compounds discharged from the cement production facility, and a method for reducing organochlorine compounds in the cement production facility. It is said.

  According to the first aspect of the present invention, immediately before preheating with the preheater, the pulverized cement raw material is heated at 300 ° C. or higher in an organic substance remover to separate the organic chlorine compound from the cement raw material, An organic substance removing step for decomposing chlorine compounds and a heat treatment gas containing the organic chlorine compound generated in the organic substance removing device are introduced into a high temperature portion of the cement manufacturing facility that is 800 ° C. or higher during normal operation of the cement manufacturing facility. An organic chlorine compound reducing method in a cement manufacturing facility comprising a gas pyrolysis step of thermally decomposing an organic chlorine compound in the heat treatment gas, wherein the organic substance remover is the cement raw material of the preheater Is connected to the upper part to be charged, the high temperature part is the lower stage part of the preheater, the kiln bottom part of the rotary kiln, the kiln front part of the rotary kiln, The heat source of the organic substance remover is at least one of the high-temperature portions of the furnace and the clinker cooler, and the heat source of the organic matter remover is an exhaust gas discharged from an upper portion of the preheater and a clinker cooler for cooling the cement clinker discharged from the rotary kiln. A method for reducing organochlorine compounds in a cement production facility, characterized in that it is exhaust gas, exhaust gas discharged from a kiln front part of a rotary kiln and / or a heated gas from a gas generator attached to the organic substance remover .

According to the first aspect of the present invention, the pulverized cement raw material (ground pulverized raw material) containing the organochlorine compound just before the preheating is put into the organic substance removing device, where the cement raw material is heated, and the organic chlorine is removed from the cement raw material. The compound is separated or the organic chlorine compound is decomposed ( organic matter removing step).
In the organic substance removing step, the heat treatment gas containing the organic chlorine compound generated in the organic substance removing device is put into a high temperature portion of 800 ° C. or higher in the cement manufacturing facility (gas pyrolysis step). Here, the organic chlorine compound (including the precursor) in the heat treatment gas is thermally decomposed.

  By the way, in the raw material process in the initial stage of cement production, for example, drying of a cement raw material having a high water content by a raw material dryer and grinding of the cement raw material by a raw material mill are performed. In the raw material dryer and the raw material mill, exhaust gas generated from the top of the preheater during preheating is introduced, and the internal temperature is about 300 ° C. Exhaust gas (especially dust) released from the raw material dryer, raw material mill, etc. through the flue to the atmosphere contained a large amount of organochlorine compounds.

  On the other hand, the cement raw material pulverized by the raw material mill is continuously fed into the upper part of the preheater. At this time, most of the organochlorine compounds adhering to the cement raw material are not thermally decomposed as the cement raw material descends in the preheater as set in advance, and the heat of the upper part of the preheater (including the heat of exhaust gas). Vaporized (separated), mixed with exhaust gas as it was, and returned to the raw material mill. As a result, organochlorine compounds were circulated in the raw material process of cement production, and the concentration was gradually increased. Therefore, the amount of dioxins released from the raw material dryer, raw material mill, etc. (raw material process part) through the flue to the atmosphere, and hence the amount of dioxins discharged from the cement production facility has increased.

  Therefore, in order to solve this problem, in the invention described in claim 1, the pulverized raw material (ground pulverized cement raw material) immediately before being preheated is put into an organic substance removing device and heated, and an organic chlorine compound is added from the cement raw material. It is configured to be removed. As a result, the circulation of the organic chlorine compound can be cut off in the raw material process of cement production, and the above-described increase in the concentration of the organic chlorine compound can be suppressed. Thereby, the discharge | release amount of organic chlorinated compounds, such as dioxins and PCBs discharged | emitted from a cement manufacturing equipment, can be reduced compared with the past.

In addition, as a raw material process part, the raw material dryer which dries a cement raw material with high moisture content, such as clay, for example, and the raw material mill which grind | pulverizes a cement raw material are employable.
Performing the organic matter removal step immediately before the preheating step means that no processing is performed on the cement raw material between the organic matter removal step and the preheating step.

The cement production facility may be a rotary kiln having a preheater and a calciner. In this case, as a high temperature part of 800 ° C. or higher, for example, a lower part of the preheater (850 ° C.), a calcining furnace (850 ° C.), a kiln bottom part of a rotary kiln (1000 ° C.), a kiln front part (1450 ° C.), and a clinker cooler The high temperature part (800 degreeC or more) etc. are mentioned.
When the high temperature part is less than 800 ° C., for example, organic chlorine compounds such as dioxins cannot be completely thermally decomposed. The preferable temperature of the high temperature part is 850 ° C. or higher. Within this range, for example, organic chlorine compounds such as dioxins can be completely pyrolyzed.

  The firing temperature of the cement, for example, the temperature in the rotary kiln is usually 1100 to 1450 ° C., which exceeds the thermal decomposition temperature of the organochlorine compound. Therefore, the organic chlorine compound is thermally decomposed and rendered harmless when the cement clinker is fired. The firing time of the rotary kiln at this time (raw material residence time = thermal decomposition time of the organic chlorine compound) is 30 minutes to 1 hour. For example, when the organic chlorine compound is heated at 900 ° C. for several seconds, it is thermally decomposed.

The structure of the organic substance removing device is not limited as long as the cement raw material after pulverization can be heated. For example, a heating screw type heater that heats the powder of cement raw material charged in a transfer pipe that is externally heated while being transferred by a screw may be used. Moreover, you may employ | adopt the heater with a heating fluidized bed and a cyclone. In this method, firstly, a ground cement material is put into a heated fluidized bed, and an organic chlorine compound is removed from the cement material. Next, the heated cement raw material is charged into a cyclone, where the cement raw material and the heat treatment gas containing the organic chlorine compound are separated.
Dust collected by the dust collector in the cement production facility (dust collected in the raw material process during cement production, dust collected in the firing process, etc.) In addition, intermediate products (such as preheated raw materials extracted from the preheater) obtained during cement production, by-products and waste during cement production may be input.

  When the heating temperature of the cement raw material by the organic substance remover is less than 200 ° C., the organic chlorine compound remains and cannot be removed practically.

  The heat source of the organic substance remover is not limited. For example, exhaust gas generated when calcining cement clinker from cement raw material (for example, exhaust gas (about 350 ° C.) supplied to the raw material mill from the top of the preheater, exhaust gas from clinker cooler, etc.) can be employed. A heated gas from a dedicated gas generator may be employed.

  The heat medium from the heat source may be supplied to the inside of the organic substance remover and the cement raw material may be directly heated. For example, a jacket provided on the outer peripheral wall of the organic substance remover may be used from the outside of the organic substance remover. The cement raw material may be supplied and heated indirectly. Of the exhaust gas generated in the cement facility, the exhaust gas having a high oxygen concentration is preferably introduced into the organic substance removing device. On the other hand, in the case of a gas having a low oxygen concentration, such as exhaust gas supplied from a preheater to a raw material dryer and a raw material mill through an exhaust gas duct, the cement raw material is supplied from the outside of the organic substance remover and heated to the jacket. Is preferable. The exhaust gas after heat exchange in the jacket can be returned to the exhaust gas duct, and the organic chlorine compound contained in the exhaust gas can be heat-treated in the raw material process of cement production.

The heating temperature of the cement raw material in the organic substance remover is 300 ° C. or higher.
When the heating temperature of the cement raw material is less than 300 ° C., the organic chlorine compound may remain in the cement raw material. The preferable heating temperature of the cement raw material is 300 to 400 ° C.

  The organic substance remover is connected to an upper part of the preheater where the cement raw material is charged, and the high temperature part includes a lower stage part of the preheater, a kiln bottom part of the rotary kiln, a kiln front part of the rotary kiln, and a calcining process. At least one of the high temperature portions of the furnace and clinker cooler.

  When the heat treatment gas generated in the organic substance remover is supplied to the front part or the bottom part of the kiln of the rotary kiln, the organochlorine compound can be thermally decomposed by the heat of firing at the time of clinker firing. When this heat treatment gas is supplied to the lower stage of the preheater or the calcining furnace, the organic chlorine compound can be thermally decomposed in a few seconds at a high temperature (850 ° C. or higher).

  In the kiln front part of the rotary kiln, the heat treatment gas may be supplied to the combustion burner together with the fuel, or may be supplied to the rotary kiln separately from the fuel. The supply position of the heat treatment gas in the rotary kiln is not limited.

  The heat source of the organic substance remover includes exhaust gas discharged from the upper part of the preheater, exhaust gas of a clinker cooler that cools the cement clinker discharged from the rotary kiln, and heating gas from a gas generator attached to the organic substance remover. Of these, at least one.

As the heat source of the organic substance remover, for example, only the exhaust gas (250 to 400 ° C.) from the top of the preheater, only the exhaust gas from the clinker cooler (250 to 1100 ° C.), or only the heating gas from the gas generator can be employed. . Two or all of these may be used.
As the heating gas, for example, air, combustion gas (including CO and CO ₂ ), etc. can be employed.
As the heating method of the gas generator, for example, burner heating can be employed.

  The invention described in claim 2 is the reduction of organochlorine compounds in the cement manufacturing facility according to claim 1, wherein the clinker cooler exhaust gas is supplied into the organic substance remover and the cement raw material is directly heated by the exhaust gas. Is the method.

According to a third aspect of the present invention, the organic matter remover has a jacket surrounding the cement raw material transfer pipe and an outer jacket surrounding the jacket, and the exhaust gas discharged from the upper part of the preheater in the jacket, The exhaust gas of the clinker cooler or the exhaust gas of the front part of the kiln of the rotary kiln is supplied, and the cement raw material is heated by supplying heated gas from the gas generator into the external jacket. This is a method for reducing organochlorine compounds in cement production facilities.
When a gas serving as a heat source is supplied to the jacket, the heat of the heated gas heats the cement raw material in the organic matter remover from the outside through the outer peripheral wall of the organic matter remover. Thereby, the density | concentration (for example, dioxin density | concentration) of the organochlorine compound in a cement raw material falls. As a result, it is possible to reduce the discharge amount of dioxins and organic chlorine compounds such as PCB discharged from the cement production facility.
A part of the outer peripheral wall of the organic substance remover may be provided or a jacket may be provided. Of the outer peripheral wall of the organic substance remover, the position where the jacket is installed is arbitrary.
The shape and size (capacity) of the jacket are not limited.
As the heat source supplied to the jacket, for example, only the exhaust gas from the top of the preheater, only the exhaust gas from the clinker cooler, or only the heated gas from the gas generator can be employed. Two or all of these may be used.

The invention according to claim 4 is a storage silo for storing the crushed cement raw material, a preheater for preheating the cement raw material supplied from the storage silo, and firing the preheated cement raw material to obtain a cement clinker. A cement manufacturing apparatus comprising a rotary kiln, comprising an organic substance remover that is provided in a cement raw material supply path between the storage silo and the preheater and separates or decomposes an organic chlorine compound from the cement raw material. The pulverization is performed by supplying exhaust gas discharged from the top of the preheater, exhaust gas of a clinker cooler that cools the cement clinker discharged from the rotary kiln, and / or exhaust gas discharged from the front of the kiln of the rotary kiln. Heating the cement material A fluidized bed is removed by separating or decomposing chlorine compounds, it is connected to the fluidized bed, a cement manufacturing apparatus and a cyclone to retrieve the cement raw material organic chlorine compounds have been removed.
The invention according to claim 5 is a storage silo for storing the crushed cement raw material, a preheater for preheating the cement raw material supplied from the storage silo, and firing the preheated cement raw material to obtain a cement clinker. A cement manufacturing apparatus comprising a rotary kiln, comprising an organic substance remover that is provided in a cement raw material supply path between the storage silo and the preheater and separates or decomposes an organic chlorine compound from the cement raw material. Is provided with a transfer pipe into which cement raw material is charged, and exhaust gas discharged from the upper part of the preheater, clinker cooler exhaust gas for cooling the cement clinker discharged from the rotary kiln and / or the rotary kiln. By supplying exhaust gas discharged from the front of the kiln A cylindrical jacket for heating the preheated cement raw material, surrounds the cylindrical jacket, a cement manufacturing apparatus and an external jacket having an inner space in which the heating gas is supplied.

  According to this invention, since the cement raw material containing the organic chlorine compound is heated by the organic substance remover before being charged into the preheater, the organic chlorine compound can be separated or decomposed from the cement raw material immediately before preheating by the preheater. In addition, the heat treatment gas containing the organic chlorine compound generated during the heat treatment in the organic substance remover is supplied to the high temperature part at 800 ° C. or higher during normal operation in the cement manufacturing facility, so that the organic chlorine compound in the heat treatment gas is reduced. It can be pyrolyzed. As a result, the amount of dioxins discharged from the cement manufacturing facility and the amount of organochlorine compounds such as PCB can be reduced as compared with the conventional case.

  Examples of the present invention will be specifically described below.

  In FIG. 1, reference numeral 10 denotes a cement firing facility to which the organic chlorine compound reducing method is applied in the cement manufacturing facility according to Embodiment 1 of the present invention. The cement firing facility 10 includes a raw material process part A for grinding a cement raw material and a firing process part B for firing the ground cement raw material.

  The raw material process section A includes a raw material storage 11 for individually storing limestone, clay, silica and iron raw materials as cement raw materials, a raw material dryer 12 for heating and drying high moisture content cement raw materials, and a raw material mill for pulverizing cement raw materials. 13, an electrostatic precipitator 30 that collects dust (powder) containing organic chlorine compounds discharged from the raw material dryer 12 and the raw material mill 13, and a storage silo 14 of cement raw material crushed by the raw material mill 13. Yes.

  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 transport facility 118. However, some cement raw materials having a high water content such as clay are supplied to the raw material dryer 12 via the high water content raw material supply facility 131. This part of the cement raw material is dried here and fed into the raw material mill 13 through the dry raw material discharge facility 132. A large number of metal balls are housed in the rotating drum of the raw material mill 13. By continuously feeding the cement raw material while rotating the rotating drum, a cement raw material powder in which the cement raw material is pulverized to about 90 μm or less is obtained. The pulverized cement raw material is charged into the storage silo 14 via the pulverized raw material transport facility 121.

The raw material dryer 12 and the raw material mill 13 are respectively supplied with exhaust gas of about 300 ° C. discharged from the upper part of the preheater 16 described later through an exhaust gas duct 21 having a bifurcated downstream side portion. 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 100 ° C. or higher. A fan F <b> 1 is provided in the vicinity of the middle portion of the exhaust gas duct 21.
The raw material dryer 12 and the raw material mill 13 are connected to respective end portions 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, the electric dust collector 30 is provided. Dust collection dust collected by the electric dust collector 30 is supplied into the middle part of the pulverized raw material transport facility 121 through the dust delivery pipe 123. Further, in the flue 129, a fan F2 is provided on the material mill 13 side on the upstream side which is a fork, and a fan F3 is provided in a portion between the electrostatic precipitator 30 and the chimney 130.

Next, the baking process part B is demonstrated concretely.
The firing process part B is heated immediately before putting the cement raw material from the storage silo 14 into the preheater 16 to separate the organic chlorine compound from the cement raw material or decompose the organic chlorine compound, and the organic substance removing device. A gas generator 102 for supplying a heating gas serving as a heat source to an external jacket (jacket) 101 provided on the outer peripheral wall 100 from the outside (outside) of the cement manufacturing facility 10, and a lower (downstream) one inside A preheater 16 that has a multi-stage cyclone 15 having a high temperature and preheats the cement raw material from which the organic chlorine compound has been removed by the organic substance removing device 100 is connected to the lower stage of the preheater 16 at the bottom of the kiln to burn the cement raw material. The rotary kiln 18 that is baked by heating in the burner 17 to obtain a cement clinker and the rotary kiln 18 in front of the kiln A clinker cooler 19 for cooling the discharged cement clinker, and a clinker silo (not shown) for temporarily storing the resulting cement clinker.

Details of the organic substance removing device 100 will be described later.
The preheater 16 preheats until the limestone in the cement raw material is decarboxylated while passing through the upper and lower cyclones 15 sequentially from the upper one so that the crushed cement raw material can be easily fired by the rotary kiln 18 in the next step. It is a multistage tower. An upstream end of the exhaust gas duct 21 is connected to the upper portion of the preheater 16.
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 at the front of the kiln by the heat of the flame from the combustion burner 17 using heavy oil or fine coal as fuel.

  That is, in the firing process part B, the cement raw material from the storage silo 14 is charged into the organic substance remover 100 through the heated raw material powder pipe 165, where it is heated to a predetermined temperature, and the organic chlorine compound is removed from the cement raw material. Thereafter, the cement raw material is preheated while flowing down each cyclone 15 of the preheater 16. Then, the cement raw material is heated by the combustion burner 17 while rotating in the kiln shell. Thereby, a cement clinker is obtained. The obtained cement clinker is cooled inside the clinker cooler 19.

Next, the organic substance removing device 100 will be described in detail with reference to FIGS.
As shown in FIGS. 1 and 2, the organic substance removing device 100 includes a rectangular casing 103 in a plan view, a cement raw material inlet 103 a formed on the upper plate of the casing 103 in the internal space of the casing 103, and A zigzag pipe 104 that connects the cement material discharge port 103b formed in the lower plate of the casing 103 in a zigzag shape in the up-down direction, and a heating that is spaced apart in a horizontal state in three stages on the zigzag pipe 104 A screw-type heating unit 105 and the outer jacket 101 are provided.

Each heating unit 105 is connected in a horizontal state in the middle of the zigzag pipe 104, and is provided with a cylindrical transfer pipe 106 into which the cement raw material is charged, and an outer periphery of the transfer pipe 106, and the cement raw material passing through the pipe A cylindrical jacket (heating means) 107 for heating to 300 ° C., a screw 108 housed in the transfer pipe 106, and a rotation motor 109 for rotating the screw 108 are provided.
The cylindrical jackets 107 are connected to each other by a single heat source delivery pipe 150 whose upstream portion is bifurcated. In the heat source delivery pipe 150, one branch pipe 151 constituting a part of the bifurcated portion is connected to a first heat source supply port 103 c formed on the lower plate of the casing 103. The other branch pipe 152 constituting the remaining portion of the bifurcated portion is connected to a second heat source supply port 103 d formed on the lower plate of the casing 103. A downstream portion of the heat source delivery pipe 150 is connected to a heat source outlet 103 e formed on the upper plate of the casing 103. Further, the downstream end of the heat source delivery pipe 150 is connected to the tip of an organic gas separation branch pipe 153 branched from the downstream part of the uppermost transfer pipe 106.

  The first heat source supply port 103c is connected to the upstream portion of the exhaust gas duct 21, and is connected to the downstream portion of the preheating branch pipe 21a provided with the fan F4 in the middle. Further, the downstream portion of the heat source introduction pipe 154 whose upstream portion is bifurcated is connected to the second heat source supply port 103d. One branch pipe 154 a constituting a part of the bifurcated portion of the heat source introduction pipe 154 is connected to the upper part of the front part of the kiln of the rotary kiln 18. The other branch pipe 154 b constituting the remaining part of the bifurcated portion of the heat source introduction pipe 154 is connected to the upper part of the clinker cooler 19. A fan F <b> 5 is provided at an intermediate portion of the heat source introduction pipe 154. The exhaust gas from the clinker cooler 19 and the exhaust gas from the front of the kiln of the rotary kiln 18 are supplied to the heat source distribution pipe 150 through the heat source introduction pipe 154 and the second heat source supply port 103d, and are sequentially supplied to each cylindrical jacket 107. .

The heat source discharge port 103e is connected to an exhaust gas outlet pipe 156 having a downstream end connected to the lower stage (about 850 ° C.) of the preheater 16 and a downstream portion provided with a valve 155.
A first branch pipe 156 a having a valve 157 and connected to the upstream portion (about 1100 ° C.) of the clinker cooler 19 is connected to a portion slightly upstream of the valve 155 in the exhaust gas outlet pipe 156. The exhaust gas outlet pipe 156 has a valve 158 in the upstream portion of the first branch pipe 156a and is connected to the end wall of the kiln front part (about 1450 ° C.) of the rotary kiln 18. A tube 156b is connected. A fan F <b> 6 is provided upstream of the exhaust gas outlet pipe 156.
A part of the outer peripheral wall of the outer jacket 101 is connected through a heating gas supply pipe 159 having one end connected to a heating gas supply unit (not shown) of the gas generator 102. The other end of the external heat exhaust gas pipe 160 having one end connected to the upstream part of the exhaust gas duct 21 is connected to the other part of the outer peripheral wall of the outer jacket 101.

  The gas generator 102 has insufficient heat to remove the organic chlorine compound from the cement raw material with the heat from the three heat sources described above (the lower part of the preheater 16, the upstream part of the clinker cooler 19, and the kiln front part of the rotary kiln 18). Used when The heated gas generated by the gas generator 102 is supplied to the internal space of the outer jacket 101 through the heated gas supply pipe 159. A part of the exhaust gas from the upper part of the preheater 16 may be supplied to the outer jacket 101.

  As described above, the heating gas of the outer jacket 101 heats the internal air of the casing 103, whereby the cement raw material flowing in the pipe 104 can be heated from the outside together with the respective heating units 105. The temperature of the internal space of the outer jacket 101 is about 300 ° C. The heated gas after use is introduced into the exhaust gas duct 21 through the external heat exhaust gas pipe 160.

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. The three valves 155, 157 and 158 are opened.
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 material having a high water content is supplied to the material dryer 12 via the high water content material supply facility 131. The clay is heated and dried in the raw material dryer 12 and then charged into the raw material mill 13 through a dry clay discharge pipe 132. 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 inside of the raw material dryer 12 is kept at 300 ° C., and the inside of the raw material mill 13 is kept at 100 ° C. or higher. In the raw material mill 13, the cement raw material containing the dry clay supplied from the raw material dryer 12 is pulverized to a particle size of approximately 90 μm or less by a large number of metal balls while being heated to about 100 ° C. The pulverized cement raw material is fed into the storage silo 14 through the pulverized raw material transport facility 121.

  Organic chlorine compounds such as dioxins and organic chlorine compounds such as PCBs, and other waste containing organic substances and chlorine (such as municipal waste and incinerated ash) are mixed as cement raw materials (for example, clay) Vaporizes in the raw material dryer 12. The dust containing the organic chlorine compound thus vaporized is collected by the electrostatic precipitator 30 through the flue 129. The dust collected is supplied into the pipe of the pulverized raw material transport equipment 121 through the dust delivery pipe 123 and is once stored in the storage silo 14 together with the cement raw material crushed in the raw material mill 13.

  Next, the cement raw material in the storage silo 14 is put into the organic substance removing device 100 through the raw material powder transport facility 165. That is, the cement raw material thrown into the spiral pipe 104 inside the casing 103 from the inlet 103 a sequentially passes through the three heating parts 105 while being transported downstream in the spiral pipe 104, and is discharged to the lower part of the casing 103. It is discharged from 103b to the top of the preheater 16. At this time, in each heating unit 105, the transfer pipe 106 is heated to about 300 ° C. by the cylindrical jacket 107, and the screw 108 is synchronously rotated by the rotary motor 109. As a result, the cement raw material input from the input port 103a is input from the cement raw material discharge port 103b through the organic removal powder pipe 165a to the upper portion of the preheater 16 at 300 ° C. or higher.

  A heat treatment gas (exhaust gas) containing an organic chlorine compound generated in the organic substance removing device 100, specifically, in the pipe of the spelling pipe 104 is sent into the downstream end of the heat source delivery pipe 150 through the organic gas separation branch pipe 153. The Thus, the heat treatment gas is mixed with the exhaust gas from each used heat source, and is sent to the exhaust gas outlet pipe 156 through the heat source discharge port 103e. Thereafter, the heat treatment gas passes through the exhaust gas outlet pipe 156 including both the branch pipes 156a and 156b, the lower stage part of the preheater 16 that becomes 800 ° C. or higher during normal operation inside the cement manufacturing facility 10, the kiln front part of the rotary kiln 18, It is supplied to the upstream part of the clinker cooler 19 and thermally decomposed.

By the way, in the raw material dryer 12 arranged in the raw material process part A, the exhaust gas generated from the upper part of the preheater 16 at the time of preheating is introduced, and the internal temperature is about 300 ° C. Therefore, dioxins vaporize. As a result, conventionally, an organic chlorine compound has been contained in exhaust gas (particularly dust) released from the raw material dryer and raw material mill through the flue through the flue.
On the other hand, the cement raw material is continuously supplied from the storage silo to the upper part of the preheater. At this time, most of the organic chlorine compounds adhering to the cement raw material are not thermally decomposed as the cement raw material descends in the pre-heater as set in advance, but by the heat of the upper part of the pre-heater (including the heat of exhaust gas). Vaporized (separated), mixed with exhaust gas as it was, and returned to the raw material mill. As a result, in the past, the organic chlorine compound was circulated in the raw material process section, and the concentration was gradually increased. Therefore, the amount of dioxins released from the raw material process section to the atmosphere, and hence the amount of dioxins discharged from the cement production facility, has increased.

On the other hand, in the cement manufacturing facility 10, the cement raw material immediately before being preheated is put into the organic substance removing device 100 and heated to remove the organic chlorine compound from the cement raw material. As a result, the circulation of the organic chlorine compound in the raw material process part A of the cement production described above can be cut off, and the high concentration of the organic chlorine compound described above can be suppressed. Thereby, the discharge | release amount of organic chlorinated compounds, such as dioxins and PCBs discharged | emitted from the cement manufacturing equipment 10, can be reduced compared with the past.
The cement raw material that has been discharged from the organic substance removing device 100 and from which the organic chlorine compound has been removed is then supplied to the firing process section B, where it sequentially flows from the uppermost cyclone 15 of the preheater 16 to the lower cyclone 15. However, it is finally preheated at about 800 ° C. Thereafter, the cement raw material is charged into the kiln bottom of the rotary kiln 18.

Next, with reference to FIG. 3, the organic chlorine compound reduction method in the cement manufacturing facility according to Embodiment 2 of the present invention will be described.
As shown in FIG. 3, the cement manufacturing facility 10A of Example 2 is replaced with the organic substance removing device 100 of Example 1, and a fluidized bed 201 for heating the cement raw material and removing the organic chlorine compound in the cement raw material. This is an example employing an organic substance removing device 200 including a cyclone 203 that is connected to an upper end portion of a fluidized bed 201 via a connecting pipe 202 and takes out a cement raw material from which an organic chlorine compound has been removed. Thereby, it becomes a simple structure compared with Example 1, and it becomes easy to maintain.

  The fluidized bed 201 is provided in a heating tower 204 having a vertical cylindrical shape for heating a cement raw material containing an organic chlorine compound, and a lower part of the outer peripheral wall of the heating tower 204, and the cement raw material from the storage silo 14 is placed in the tower. And a charging tube 205 for charging. The raw material powder transport facility 165 is connected to an upstream portion of the input pipe 205. A perforated plate (not shown) is provided horizontally at the bottom of the heating tower 204. The three types of heat source gases (exhaust gas from the top of the preheater 16, exhaust gas from the front of the kiln of the rotary kiln 18, and exhaust gas from the clinker cooler 19) always pass through each hole of the perforated plate at a constant pressure. It is blown up in the tower.

Therefore, the cement raw material charged into the heating tower 204 from the charging pipe 205 at a constant flow rate gradually rises while turning in the internal space of the heating tower 204. Meanwhile, the organic chlorine compound is vaporized by the heat of the heat source gas and separated from the cement raw material, or the organic chlorine compound is thermally decomposed. Thereafter, the organic chlorine compound and the cement raw material from which the organic chlorine compound has been removed are supplied to the cyclone 203 via the connecting pipe 202.
Here, the organic chlorine compound passes from the upper part of the cyclone 203 through the exhaust gas outlet pipe 156, the lower stage part of the preheater 16 that becomes 800 ° C. or higher during normal operation inside the cement manufacturing facility 10A, the kiln front part of the rotary kiln 18, the clinker cooler. 19 are respectively supplied to the upstream portion and thermally decomposed. On the other hand, the cement raw material from which the organic chlorine compound has been removed is fed from the bottom of the cyclone 203 to the top of the preheater 16 through the organic removal powder pipe 165a.
Other configurations, operations, and effects are within a range that can be estimated from the first embodiment, and thus description thereof is omitted.

Here, the result of investigating the reduction rate of PCB in the exhaust gas released to the atmosphere by comparing the one using the cement production facility 10 of Example 1 and the one using the conventional cement production facility is reported.
That is, the PCB content in the feed material was reduced from 500 ng / g to 10 ng / g. Further, PCB content of dedusted gas is decreased from 10000 ng / Nm ³ so far up to 250 ng / Nm ^3.

It is a schematic block diagram of the cement baking equipment to which the organic chlorine compound reduction method in the cement manufacturing equipment concerning Example 1 of this invention was applied. It is a schematic block diagram of the organic substance removal device which comprises a part of cement manufacturing facility to which the organic chlorine compound reduction method in the cement manufacturing facility which concerns on Example 1 of this invention was applied. It is a schematic block diagram of the organic substance removal device which comprises a part of cement manufacturing equipment to which the organic chlorine compound reduction method in the cement manufacturing equipment concerning Example 2 of this invention was applied.

Explanation of symbols

10,10A Cement production facility,
16 Preheater,
18 Rotary kiln,
19 Clinka cooler,
100,200 Organic substance remover,
101 External jacket (jacket).

Claims (5)

Immediately before preheating with the preheater, the pulverized cement raw material is heated in an organic substance remover at 300 ° C. or higher to separate the organic chlorine compound from the cement raw material, or an organic substance removing step for decomposing the organic chlorine compound; ,
The heat treatment gas containing the organic chlorine compound generated in the organic substance removing device is put into a high temperature part in the cement production facility that is 800 ° C. or higher during normal operation of the cement production facility, and the organic chlorine compound in the heat treatment gas is A method for reducing organochlorine compounds in a cement production facility comprising a gas pyrolysis step for pyrolysis,
The organic matter remover is connected to an upper portion of the preheater where the cement raw material is charged,
The high temperature part is at least one of a lower stage part of the preheater, a kiln bottom part of the rotary kiln, a kiln front part of the rotary kiln, a calcining furnace, and a high temperature part of the clinker cooler,
The heat source of the organic substance remover is exhaust gas discharged from the upper part of the preheater, exhaust gas of a clinker cooler that cools the cement clinker discharged from the rotary kiln, exhaust gas discharged from the front of the kiln of the rotary kiln and / or organic matter removal thereof. A method for reducing an organochlorine compound in a cement manufacturing facility, characterized in that the heated gas is from a gas generator attached to the vessel.   The method for reducing organochlorine compounds in a cement production facility according to claim 1, wherein the clinker cooler exhaust gas is supplied into the organic substance remover and the cement raw material is directly heated by the exhaust gas. The organic matter remover has a jacket surrounding the cement raw material transfer pipe and an outer jacket surrounding the jacket,
The exhaust gas discharged from the upper part of the preheater, the clinker cooler exhaust gas, or the exhaust gas from the front of the rotary kiln kiln is supplied into the jacket, and the heated gas from the gas generator is supplied into the outer jacket. The method for reducing an organochlorine compound in a cement manufacturing facility according to claim 1, wherein the cement raw material is heated . A storage silo for storing the ground cement material;
A preheater for preheating the cement raw material supplied from the storage silo;
In a cement manufacturing apparatus equipped with a rotary kiln that fires preheated cement raw material and obtains a cement clinker,
Provided in a cement raw material supply path between the storage silo and the preheater, and having an organic substance remover for separating or decomposing an organic chlorine compound from the cement raw material,
The organic matter remover is supplied with exhaust gas discharged from the top of the preheater, exhaust gas of a clinker cooler that cools the cement clinker discharged from the rotary kiln, and / or exhaust gas discharged from the front of the kiln of the rotary kiln. By heating the pulverized cement raw material and separating or decomposing and removing the organic chlorine compound in the cement raw material, and a cyclone connected to the fluidized bed and removing the cement raw material from which the organic chlorine compound has been removed And a cement manufacturing apparatus. A storage silo for storing the ground cement material;
A preheater for preheating the cement raw material supplied from the storage silo;
In a cement manufacturing apparatus equipped with a rotary kiln that fires preheated cement raw material and obtains a cement clinker,
Provided in a cement raw material supply path between the storage silo and the preheater, and having an organic substance remover for separating or decomposing an organic chlorine compound from the cement raw material,
This organic substance remover is provided with a transfer pipe into which cement raw material is charged, an exhaust gas discharged from the upper part of the preheater, an exhaust gas of a clinker cooler that cools the cement clinker discharged from the rotary kiln, and / Or a cylindrical jacket for heating the preheated cement raw material by supplying exhaust gas discharged from the front of the kiln of the rotary kiln;
A cement manufacturing apparatus comprising an outer jacket surrounding the cylindrical jacket and having an inner space to which heated gas is supplied.

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