JP5703851B2 - Cement clinker manufacturing apparatus and manufacturing method - Google Patents

Description

  The present invention relates to a cement clinker manufacturing apparatus and a manufacturing method for reducing the calorific value when a cement clinker is manufactured.

  It can be said that the major change in the cement manufacturing technology in recent years was the progress of technology to reduce the calorific value of cement clinker. In other words, from the wet firing method that required a large calorific value by adding water to the blended raw material and then firing it, the dry material that reduces the calorific value by crushing and calcining the cement raw material after drying with hot air This is a series of developments such as the development of a new suspension system that further shifts to the firing method, and calcines the adjusted raw material in advance with a pre-heater, and puts the obtained calcined raw material into a rotary kiln to further reduce the calorific value.

  In addition to the above method, as a measure to reduce the calorific value of cement clinker, the main chemical composition of the blended raw material is changed to increase the amount of liquid phase at the time of firing, making it easier to produce cement clinker even at relatively low temperatures. Alternatively, there is a method of adding a mineralizer such as fluorite (calcium fluoride) that promotes the firing reaction to the cement raw material. There is also a method of using waste as raw fuel.

  However, by changing the main chemical composition of the raw material, the content of alumina, iron, sulfur, etc. is increased to increase the amount of liquid phase at high temperatures or to make the mineral composition easy to generate at relatively low temperatures. The clinker mineral composition is different from Portland cement. For this reason, when concrete or mortar is used, there is a problem that it exhibits unique fluidity and strength and cannot be used in a wide range of applications like ordinary Portland cement that users are accustomed to.

  In addition, a method of adding mineralizers such as fluorite to cement raw materials causes the constituent elements to volatilize in the rotary kiln and adhere to the inner wall of the rotary kiln or suspension type preheater (hereinafter referred to as preheater), causing coating problems. Cause the cement to have unique physical properties due to the action of the constituents, or rarely cause the clinker to fuse in the cement kiln due to fluctuations in the amount of mineralizer added. .

  Due to these problems, the above two methods are not only main measures for reducing the calcining heat of the clinker, but tend to be only secondary measures.

  Therefore, the inventors have the melting point higher than the temperature of the liquid layer in the clinker at the time of clinker firing, and are the main minerals of the clinker, based on the newly discovered clinker mineral crystal growth mechanism in the following Patent Documents 1 and 2. Accelerate the generation of alite by introducing a material that forms the core of alite or a nuclear material containing the material that forms the core of alite from the front side of the raw material process and the rotary kiln (hereinafter referred to as a rotary kiln). Thus, the invention of the purpose of reducing the calorific value was performed.

  The present invention uses the growth mechanism of alite, the main clinker mineral, without changing the main chemical composition and mineral composition of general-purpose Portland cement. The purpose is to produce a clinker. When alite starts crystal growth using another substance as a nucleus, if the substance that becomes the nucleus coexists at the time of liquid phase formation, it becomes about 1250 as a crystal nucleus. It is noted that alite begins to crystallize with the formation of the liquid phase at temperatures above ℃.

Japanese Patent No. 3969445 Japanese Patent No. 4010339

  By the way, since the liquid phase of clinker generally starts to be generated between 1200 to 1300 ° C., the core substance does not decompose or melt even if it comes into contact with the liquid phase, and is baked in a rotary kiln. A substance that exists stably as a solid phase is preferred.

  For this reason, a substance having a melting point of 1300 ° C. or higher is suitable as a core substance. For example, a cement clinker is an easily available substance in a cement factory. By using this cement clinker as a core material, the generation of alite is promoted, leading to a decrease in the calorific value of the clinker.

  In addition, the substance that becomes the core of alite may be mixed in the cement raw material in advance, or the raw material may be charged to a lower temperature side than the liquid phase generation region of the rotary kiln during firing. Therefore, the finer the particle size of the substance serving as the nucleus, the greater the effect, which is preferable.

  From the above, in the inventions of Patent Documents 1 and 2, the cement clinker is produced when a blended raw material composed of a plurality of cement raw materials mixed in the raw material step is fired in the firing step to produce a cement clinker containing alite. A cement clinker, cement or refractory brick that has a melting point higher than the temperature of the liquid phase and is the core of the production of the cement clinker, and at least the cement raw material and the blended raw material in the raw material step Mixing into one led to the promotion of alite formation in the rotary kiln.

  However, in the inventions of Patent Documents 1 and 2, when a substance serving as a crystal nucleus is mixed in at least one of the cement raw material and the blended raw material in the raw material step, the pulverized clinker pulverized material and dust collection Since the clinker powder thus used is used, the clinker pulverized product and the clinker powder are usually cooled to 100 ° C. or lower, and there is a problem that heat loss occurs when the clinker powder is put into a high-temperature baking process.

  The present invention has been made in view of such circumstances, and by taking out a part of a cement raw material and / or fuel containing a halogen element and firing it, the production of alite is promoted and put into a high-temperature firing process. It is an object of the present invention to provide a manufacturing apparatus and a manufacturing method for a cement clinker that prevent heat loss at the time and reduce the calorific value of the cement clinker.

In order to solve the above problems, the invention according to claim 1 is a preheater for preheating the cement raw material using a cement raw material and / or fuel containing a halogen element, and the cement raw material is disposed downstream of the preheater. A cement clinker manufacturing apparatus comprising a rotary kiln for firing, an extraction line for extracting a part of the cement raw material from a cyclone chute of the preheater, and firing the cement raw material extracted from the extraction line And a return line for returning a part of the cement raw material that has been baked in the baking means and crystallized alite to the rotary kiln.

  The invention according to claim 2 is the invention according to claim 1, wherein the firing means is a firing furnace for firing at 1200 ° C. or higher, and further includes a supply line for supplying a substance containing a halogen element. It is characterized by being.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the firing means directly contacts a halogen-containing material containing halogen to the cement raw material supplied from the extraction line. Halogen separation means for generating a flammable gas containing halogen and a residue, halogen recovery means for recovering the halogen from the flammable gas containing halogen discharged from the halogen separation means, and the halogen recovery means And a gas supply line for supplying the combustible gas after the halogen is recovered as a fuel for the cement clinker manufacturing apparatus.

  Furthermore, the invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the kiln bottom of the rotary kiln is provided with chlorine recovery means for recovering a part of the exhaust gas. It is a feature.

The invention according to claim 5 is a method for producing a cement clinker using the cement clinker apparatus according to claim 1 or 2, wherein the inside is maintained in a temperature atmosphere of 1200 ° C. or higher. in, and calcined by supplying a part of the cement material from the chute of the cyclone of the preheater, a portion of the cement raw materials alite crystallized out by the calcination characterized in that supplied to the rotary kiln is there.

  A sixth aspect of the present invention is a cement clinker manufacturing method using the cement clinker manufacturing apparatus according to the third aspect, wherein the halogen separation is performed in a temperature atmosphere of 1200 ° C. or higher. A part of the cement raw material is supplied from the cyclone chute of the preheater to the means and fired, a part of the fired cement raw material is supplied to the rotary kiln, and the halogen is recovered by the halogen recovery means. After that, the combustible gas is supplied as fuel to the cement clinker production apparatus.

In the cement clinker manufacturing apparatus according to any one of claims 1 to 4 and the cement clinker manufacturing method according to any one of claims 5 to 6, the cement raw material may be preheated using a cement raw material and / or fuel containing a halogen element. A part of the cement raw material is extracted from the cyclone chute of the preheater when the cement clinker is manufactured by preheating and supplying the calcined exhaust gas to a rotary kiln maintained in a high-temperature atmosphere and firing it. An extraction line for extracting the cement material, a firing means for firing the cement raw material extracted from the extraction line, and a part of the cement raw material that has been fired in the firing means and crystallized alite is returned to the rotary kiln. And the above cement raw material containing a halogen element. A part is extracted and the cement raw material is fired at a low temperature to promote the generation of alite contained in the cement raw material. By returning the fired cement raw material to the rotary kiln, A part or all of them become crystallites of alite, and the generation of alite can be promoted from a low temperature, and the calorific value of cement clinker can be reduced. This makes it possible to produce a cement clinker even at a relatively low temperature without changing the main chemical composition of the cement raw material, and it can be used for general-purpose Portland cement.

  In the invention described in claim 2, since the firing means is a firing furnace that fires at 1200 ° C. or higher, a part of the cement raw material extracted from the cyclone chute of the preheater is included in the cement raw material. It can be fired while promoting the generation of alite, and the fired cement raw material can be fed into the rotary kiln at a high temperature. As a result, when firing cement clinker in the rotary kiln, heat loss can be eliminated and the length of the rotary kiln can be shortened, leading to a reduction in equipment costs, power costs, and maintenance costs. .

  Furthermore, since the firing furnace is provided with a supply line for supplying a substance containing a halogen element, firing of the cement raw material supplied into the firing furnace can be promoted. Thereby, the fuel cost used for the said baking furnace can be held down.

  According to invention of Claim 3, the said baking means makes the halogen-containing substance containing a halogen contact the said cement raw material supplied from the said extraction line directly, The combustible gas containing the said halogen, and a residue Separating the halogen from the flammable gas containing the halogen discharged from the halogen separating means, and the halogen after the halogen is collected by the halogen collecting means. Since it has a halogen-containing fuel conversion system that includes a gas supply line that supplies combustible gas as fuel for the cement clinker manufacturing apparatus, one of the cement raw materials extracted from the cyclone chute of the preheater In addition to easily removing harmful effects caused by halogens such as chlorine and bromine in the parts, The generation of alite, which is included as part of the serial cement material can be fired while encouraging accelerated. As a result, firing of the cement clinker can be promoted in the rotary kiln.

  According to the invention of claim 4, the rotary kiln is provided with chlorine recovery means for recovering part or all of the exhaust gas of the cement raw material fired in the firing means at the bottom of the rotary kiln. When the cement raw material is supplied and the cement clinker is fired, even if chlorine stays in the rotary kiln, it can be easily removed and a high-quality cement clinker can be obtained.

It is a schematic block diagram which shows 1st Embodiment of the manufacturing apparatus of the cement clinker of this invention. It is a schematic block diagram which shows the modification of 1st Embodiment of the manufacturing apparatus of the cement clinker of this invention. It is a schematic block diagram which shows 2nd Embodiment of the manufacturing apparatus of the cement clinker of this invention. It is a schematic block diagram which shows 3rd Embodiment of the manufacturing apparatus of the cement clinker of this invention.

(Embodiment 1)
FIG. 1 shows a first embodiment of the cement clinker production apparatus of the present invention, and FIG. 2 shows a modification thereof.
As shown in FIG. 1, in the first embodiment, a rotary kiln 1 for firing cement raw material and a cement raw material provided in series on the left kiln bottom 2 in the figure of the rotary kiln 1 are preheated. Preheater 3, a main burner 19 for heating the inside of the furnace front 24 on the right side of the figure, a clinker cooler 20 for cooling the cement clinker after firing to the furnace front 24, and the lowermost stage of the preheater 3 The extraction line 6 for extracting the cement raw material from the chute 5 of the cyclone 4, the firing furnace 8 connected to the extraction line 6, and the cement raw material baked in the firing furnace 8 to crystallize the alite are rotary kiln 1. And a return line 9 for returning to the kiln bottom 2 is schematically configured.

    Here, the preheater 3 is composed of a plurality of (four in the figure) cyclones 4a to 4d arranged in series in the vertical direction, and the cement raw material is supplied to the first cyclone 4a. . Further, between the third-stage cyclone 4c and the fourth-stage cyclone 4d, combustion exhaust gas is introduced from the kiln bottom 2 of the rotary kiln 1 to the lower end portion and supplied from a fuel supply line (not shown) to the inside. A calcining furnace 21 provided with a combustion apparatus for fuel such as coal is provided.

  The cement raw material supplied to the uppermost cyclone 4a is preheated by the high-temperature exhaust gas from the rotary kiln 1 that rises from below as the cement raw material sequentially falls to the lower cyclone 4, and the second stage from the bottom. After being extracted from the cyclone 4 c and sent to the calcining furnace 21, and fired in the calcining furnace 21, the cyclone 4 d at the lowermost stage is introduced into the kiln bottom 2 of the rotary kiln 1 through the chute 5. ing.

  Further, the combustion exhaust gas discharged from the rotary kiln 1 is sent to the lowermost cyclone 4d through the calcining furnace 21, and is sequentially sent to the upper cyclone to preheat the cement raw material, and finally Is exhausted from the upper part of the uppermost cyclone 4 a by the exhaust fan 23 through the exhaust line 22.

  Further, in the preheater 3, an extraction line 6 for extracting the cement raw material from the chute 5 of the lowermost cyclone 4 d is provided, and the leading end of the extraction line 6 is connected to the firing furnace 8. Thereby, a part of the cement raw material from the preheater 3 is introduced into the firing furnace 8. The firing furnace 8 is provided with a burner for continuously heating the cement raw material to 1200 ° C. or higher. Further, the firing furnace 8 can correspond to a fluidized bed supplied with combustion exhaust gas from the rotary kiln 1. The firing furnace 8 is provided with a supply line 10 for supplying a substance containing a halogen element, and is connected with a return line 9 for returning the cement raw material fired in the firing furnace 8 to the rotary kiln 1.

  Further, in the modification of the first embodiment shown in FIG. 2, a chlorine bypass pipe 17 is connected to a duct that sends exhaust gas from the kiln bottom 2 of the rotary kiln 1 to the calcining furnace 21, and is extracted by the chlorine bypass pipe 17. Chlorine recovery means for removing a chlorine content by sending a part of the exhausted gas to the bag filter 18 at the subsequent stage is provided.

Next, an embodiment of a cement clinker manufacturing method according to the present invention using the cement clinker manufacturing apparatus shown in the first embodiment will be described.
First, as shown by the solid line arrow in the figure, the cement raw material charged into the first-stage cyclone 4a of the preheater 3 is dropped from the rotary kiln 1 that rises from below as the cyclones 4b to 4d are sequentially lowered. Preheated by high-temperature exhaust gas, and finally introduced into the kiln bottom 2 of the rotary kiln 1 from the chute 5 of the lowermost cyclone 4d.

  At this time, a part of the cement raw material is extracted from the extraction line 6 connected to the chute 5 of the lowermost cyclone 4 d and supplied to the firing furnace 8. The amount of the cement raw material extracted from the chute 5 of the lowermost cyclone 4d is 5% or less of the total amount of the cement raw material, preferably 1% or less. Then, a substance containing a halogen element is supplied to the firing furnace 8 from a supply line 10 connected to the firing furnace 8. Examples of the substance containing a halogen element include calcium fluoride, magnesium fluoride, waste plastic, and chlorine bypass dust. At this time, the amount of F (fluorine) in the cement raw material fired in the firing furnace 8 is 0.2% or more, preferably 0.3% or more, and MgO also acts as a flux. The amount of MgO in the cement raw material fired in the furnace 8 is 1.0% or more, preferably 1.5% or more.

  The part of the cement raw material and the halogen-containing substance supplied to the firing furnace 8 are continuously heated by a burner provided in the firing furnace 8 and fired at a temperature of 1200 ° C. or higher. When the cement raw material is fired at 1200 ° C. or higher, alite is crystallized as the liquid phase of the cement raw material is generated. Then, the cement raw material from which the alite is crystallized is introduced into the kiln bottom 2 of the rotary kiln 1 through a return line 9 connected to the firing furnace 8.

  Thus, the cement raw material introduced into the kiln bottom 2 of the rotary kiln 1 is caused by the combustion exhaust gas from the main burner 19 in the process of being gradually sent from the kiln bottom 2 side to the front kiln 24 side in the rotary kiln 1. It is heated and baked to become a clinker. At this time, since a portion of the cement raw material introduced from the firing furnace 8 has already started to crystallize, this becomes a crystal nucleus and is directly introduced into the rotary kiln 1 from the chute 5 of the lowermost cyclone 4d. Further, the generation of alite as the cement raw material is promoted, and as a result, the calorific value of the cement clinker is reduced.

  By the way, the chlorine content and alkali content contained in the cement raw material are volatilized and transferred into the exhaust gas in a high temperature (about 1400 ° C.) atmosphere in the rotary kiln 1. And when this exhaust gas is exhausted from the kiln bottom 2 of the rotary kiln 1 to the pre-heater 3 side and rises sequentially from the lower part to the upper cyclones 4d to 4a, it is cooled by preheating the cement raw material, The chlorine content contained in the material will again move to the cement raw material side.

  As a result, since the chlorine content circulates in the system composed of the rotary kiln 1 and the preheater 3, the internal chlorine concentration gradually rises due to the chlorine content newly introduced into the system from the combustion exhaust gas or the cement raw material. The cyclone of the pre-heater 3 is blocked, and the operation is hindered.

  Therefore, in the modification of the first embodiment, as shown in FIG. 2, by using the chlorine recovery means 16, a part of the exhaust gas is periodically extracted from the chlorine bypass pipe 17 and cooled to reduce the chlorine content. By collecting it as an alkali chloride in the bag filter 18 at the subsequent stage, an increase in the chlorine concentration in the system is prevented.

  And the cement clinker which reached | attained before the kiln 24 falls in the clinker cooler 20, and is sent to the right side in a figure as shown by the arrow in a figure. At this time, the air is cooled to a predetermined temperature by the air supplied into the clinker cooler 20 and finally taken out from the clinker cooler 20.

(Embodiment 2)
FIG. 3 shows a second embodiment of the cement clinker manufacturing apparatus according to the present invention. The same components as those shown in FIG.
As shown in FIG. 3, in the second embodiment, a combustor containing chlorine is used as a firing means 7 in a cement clinker manufacturing apparatus including a preheater 3 composed of a rotary kiln 1, a four-stage cyclone 4, a calciner 21, and the like. A waste fueling system is provided for pre-treating the plastic waste and introducing it into the rotary kiln 1.

  The waste fueling system is provided with a sorting device 25 provided on the most upstream side of the waste fueling system. This sorting device 25 treats combustible plastic waste to be treated with high chlorine content such as polyvinyl chloride and polyvinylidene chloride by specific gravity sorting or infrared sorting (hereinafter abbreviated as chlorine-containing plastic). And wastes with low chlorine content such as polyethylene and polypropylene (hereinafter abbreviated as low chlorine concentration plastics).

  And the low chlorine concentration plastic separated by this sorter 25 is thrown into the inside from the kiln 24 of the rotary kiln 1 as a part of the fuel via the waste fuel supply line 26. The waste fuel supply line 26 may be charged with the low chlorine concentration plastic as part of its fuel in the calcining furnace 21 instead of the rotary kiln 1. On the other hand, the chlorine-containing plastic separated by the sorting device 25 is introduced from the thermal decomposition line 27 into the subsequent thermal decomposition furnace (halogen separation means) 12.

  The pyrolysis furnace 12 is a cylindrical pyrolysis furnace provided rotatably around an axis and supplied with chlorine-containing plastic. A pyrolysis line 27 is connected to one end of the pyrolysis furnace 12 and the other end is provided. A recovery line (return line) 15 is connected. Further, a supply pipe 29 for introducing sewage sludge is connected to the one end side. Further, a burner for firing the cement raw material is provided inside the pyrolysis furnace 12.

  Here, the sewage sludge is supplied mainly as an adhesion preventing material, and instead of this, a soil material such as clay, a paper material, wood, a plastic film, or the like is applicable. At this time, if waste such as sewage sludge, construction waste wood or waste plastic film is used instead, it is possible to simultaneously treat these wastes.

  Furthermore, a heat medium supply line (extraction line) 11 for extracting the cement raw material from the chute 5 of the lowermost cyclone 4d as a heat medium and supplying it to the pyrolysis furnace 12 is provided at one end side of the pyrolysis furnace 12. It is connected.

  On the other hand, the other end of the pyrolysis furnace 12 is connected to a recovery line 15 for returning the cement raw material containing the pyrolysis residue fired in the pyrolysis furnace 12 to the kiln bottom 2 of the rotary kiln 1. In addition, a cracked gas extraction line 30 is connected to the upper portion of the pyrolysis furnace 12 to send the pyrolysis gas generated in the pyrolysis furnace 12 to a gas cleaning device (halogen recovery means) 13 in the subsequent stage.

  The gas cleaning device 13 is configured to bring an alkali component such as calcium hydroxide added from a supply pipe 13a into contact with the pyrolysis gas (combustible gas) discharged from the pyrolysis furnace 12, and in the pyrolysis gas. In order to remove the chlorine content contained in the salt as a salt such as calcium chloride from the pyrolysis gas, various wet or dry gas cleaning apparatuses can be applied. Here, reference numeral 13 b in the figure is a discharge pipe for the calcium chloride aqueous solution and the like, and reference numeral 13 c is a return pipe for returning the pyrolysis gas containing unreacted alkali components to the inlet of the gas cleaning device 13.

  A gas supply line 14 for supplying the combustible pyrolysis gas cleaned by the gas cleaning device 13 as part of the fuel into the calcining furnace 21 is provided on the discharge side of the gas cleaning device 13. It is connected.

  In the preheater 3, the combustion exhaust gas introduced from the kiln bottom 2 of the rotary kiln 1 is gradually cooled by preheating the cement raw material in the course of being sequentially sent to the upper cyclones 4d to 4a. For this reason, since the cement raw material which was about 270 ° C. in the uppermost cyclone 4a becomes about 879 ° C. in the lowermost cyclone 4d, the above-mentioned cement raw material is extracted from any of the cyclones 4a to 4d. A high-temperature cement raw material in the range of about 250 ° C. to 900 ° C. necessary for pyrolysis can be supplied to the pyrolysis furnace 12.

  Therefore, in the present embodiment, as an example, the case where the high temperature cement raw material is extracted from the chute 5 of the lowermost cyclone 4d is shown, but considering the properties of the waste and the specification use of the combustible gas, The heating temperature can be selected by appropriately selecting the cyclones 4a to 4d to be extracted.

  Moreover, it is also possible to provide the chlorine collection | recovery means 16 like the modification of the said 1st Embodiment shown in FIG. In this case, a chlorine bypass pipe 17 is connected to a duct for sending the exhaust gas from the kiln bottom 2 of the rotary kiln 1 to the calcining furnace 21, and a part of the exhaust gas extracted by the chlorine bypass pipe 17 is removed from the bag filter at the rear stage. 18 to remove chlorine. Further, by connecting the heat medium supply line 11 (dotted line in FIG. 2) to the chlorine bypass pipe 17, a dusty high-temperature cement raw material containing a large amount of chlorine may be extracted and supplied to the pyrolysis furnace 12.

  In this case, since the cement raw material is contained in the exhaust gas in the form of dust, the collected coarse particles are additionally provided in the middle of the heat medium supply line 11 with a dust collecting means such as a cyclone. It is preferable to supply only the granular cement raw material to the pyrolysis furnace 12.

Next, an embodiment of a cement clinker manufacturing method according to the present invention using the cement clinker manufacturing apparatus shown in the second embodiment will be described.
First, as shown by the solid line arrow in the figure, the cement raw material charged into the first-stage cyclone 4a of the preheater 3 is dropped from the rotary kiln 1 that rises from below as the cyclones 4b to 4d are sequentially lowered. Preheated by high-temperature exhaust gas, and finally introduced into the kiln bottom 2 of the rotary kiln 1 from the lowermost cyclone 4d.

  And in this rotary kiln 1, in the process gradually sent from the kiln bottom 2 side to the kiln front 24 side, it is heated by the combustion exhaust gas from the main burner 19 and baked to become a clinker. Next, the clinker that has reached the front of the kiln 24 falls into the clinker cooler 20 and is sent to the right in the drawing, as indicated by an arrow in the drawing. At this time, the air is cooled to a predetermined temperature by the air supplied into the clinker cooler 20 and finally taken out from the clinker cooler 20.

  By the way, also in this 2nd Embodiment, the chlorine content and alkali content which are contained in a cement raw material volatilize in the high temperature (about 1400 degreeC) atmosphere in the rotary kiln 1, and transfer to waste gas. And when this exhaust gas is exhausted from the kiln bottom 2 of the rotary kiln 1 to the pre-heater 3 side and rises sequentially from the lower part to the upper cyclones 4d to 4a, it is cooled by preheating the cement raw material, The chlorine content contained in the material will again move to the cement raw material side.

  As a result, since the chlorine content circulates in the system composed of the rotary kiln 1 and the preheater 3, the internal chlorine concentration gradually rises due to the chlorine content newly introduced into the system from the combustion exhaust gas or the cement raw material. The cyclone of the pre-heater 3 is blocked, and the operation is hindered. For this reason, as shown in FIG. 2, it is possible to prevent the chlorine concentration in the system from increasing by using the chlorine recovery means 16 of the modification of the first embodiment.

  In parallel with the production of the cement clinker, the combustible waste to be treated containing chlorine-containing plastic is put into the sorting device 25 and separated into chlorine-containing plastic and other wastes such as low chlorine-concentration plastic. . The low chlorine concentration plastic is directly injected into the rotary kiln 1 from the front 24 side of the kiln 1 through the waste fuel supply line 26 to be burned in the rotary kiln 1 and used as a part of the fuel. .

  On the other hand, the chlorine-containing plastic separated by the sorting device 25 is introduced from the thermal decomposition line 27 into the subsequent thermal decomposition furnace 12. In parallel with this, the cement raw material is extracted from the lowermost cyclone 4 d or the chlorine bypass pipe 17 (FIG. 2) by the heat medium supply line 11 and supplied to the pyrolysis furnace 12.

Then, in the pyrolysis furnace 12, the chlorine-containing plastic is pyrolyzed by directly contacting the cement raw material. As a result, a pyrolysis gas mainly containing hydrogen chloride and a pyrolysis residue mainly composed of carbide from which most of the halogen has been removed are generated in the pyrolysis furnace 12. Further, a pyrolysis furnace 12 is continuously heated by the burner, by calcining the cement raw material at 1200 ° C. or higher, alite with the generation of the liquid phase of the cement material crystallizes out.

  At this time, the sewage sludge supplied from the sewage sludge supply pipe 29 prevents the chlorine-containing plastic and its pyrolysis residue from adhering to the inner wall of the pyrolysis furnace 12. In addition, when a large amount of water contained in the sewage sludge becomes water vapor, volatilization of chlorine from the waste during the thermal decomposition is promoted, and in parallel, the ammonia content contained in the sewage sludge is Reacts with volatilized chlorine to produce ammonium chloride. As a result, the residue of chlorine in the thermal decomposition residue is minimized.

  Then, the cement raw material containing the pyrolysis residue is introduced from the recovery line 15 to the kiln bottom 2 of the rotary kiln 1. Thereby, a cement raw material and a thermal decomposition residue are finally sent to the rotary kiln 1 with other cement raw materials, and are baked. At this time, the combustible component contained in the pyrolysis residue is used as a part of the fuel in the calcining furnace 21 or the rotary kiln 1, and the cement raw material supplied from the recovery line 15 has already been crystallized from alite. Since it begins to be taken out, the production | generation of the alite of the said cement raw material directly introduced into the rotary kiln 1 from the chute | shoot 5 of the lowermost cyclone 4d is accelerated | stimulated, and the baking calorie | heat amount of a cement clinker reduces by extension.

  On the other hand, the combustible pyrolysis gas is supplied into the calcining furnace 21 by the gas supply line 14 after removing halogen such as chlorine in the gas cleaning device 13 and used as part of the fuel. . Further, since the gas cleaning device 13 removes chlorine and the like contained in the pyrolysis gas and then returns to the calcining furnace 21, the chlorine recovery means 16 comprising the chlorine bypass pipe 17 and the bag filter 18; Similar functions are obtained.

  In this way, combustible waste containing chlorine can be processed smoothly in a cement clinker manufacturing apparatus, and the calorific value of the combustible waste can be reduced without causing adverse effects due to chlorine contained in the waste. It can be effectively used as a part of fuel for clinker production.

(Embodiment 3)
FIG. 4 shows a third embodiment of the cement clinker production apparatus according to the present invention. The same components as those shown in FIGS. Turn into.
As shown in FIG. 4, in the third embodiment, the firing furnace 8 of the first embodiment shown in FIG. 1 is provided as the firing means 7, and the pyrolysis furnace 12 used in the second embodiment. A waste fueling system is provided for pre-treating and introducing the combustible plastic waste containing chlorine with a rotary kiln 1.

  In the third embodiment, the heating medium supply line 11 described in the second embodiment is added to the extraction line 6 for extracting the cement raw material from the chute 5 of the lower cyclone 4d described in the first embodiment. Is connected. And the recovery line 15 which returns the said cement raw material discharged | emitted from this pyrolysis furnace 12 to the kiln bottom 2 of the rotary kiln 1 is connected to the pyrolysis furnace 12 of the said waste fuel conversion system. The recovery line 15 is provided with a dust cleaning device 31 for cleaning the cement raw material discharged from the pyrolysis furnace 12 with water to remove salts.

  In addition, a pyrolysis gas is supplied to the firing furnace 8 by supplying a part of the pyrolysis gas generated in the pyrolysis furnace 12 to a cracking gas extraction line 30 that is sent to a gas cleaning device 13 connected to the pyrolysis furnace 12. The gas supply line 28 is branched. Further, a calcium chloride aqueous solution supply pipe 13 d for supplying a part of the calcium chloride aqueous solution to the firing furnace 8 is connected to the calcium chloride aqueous solution discharge pipe 13 b removed from the pyrolysis gas connected to the gas cleaning device 13. Yes.

  Moreover, it is also possible to provide the chlorine collection | recovery means 16 like the modification of the said 1st Embodiment shown in FIG. In this case, a chlorine bypass pipe 17 is connected to a duct for sending the exhaust gas from the kiln bottom 2 of the rotary kiln 1 to the calcining furnace 21, and a part of the exhaust gas extracted by the chlorine bypass pipe 17 is removed from the bag filter at the rear stage. 18 to remove chlorine. Further, by connecting the heat medium supply line 11 (dotted line in FIG. 2) to the chlorine bypass pipe 17, a dusty high-temperature cement raw material containing a large amount of chlorine may be extracted and supplied to the pyrolysis furnace 12.

  In this case, since the cement raw material is contained in the exhaust gas in the form of dust, the collected coarse particles are additionally provided in the middle of the heat medium supply line 11 with a dust collecting means such as a cyclone. It is preferable to supply only the granular cement raw material to the pyrolysis furnace 12.

Next, an embodiment of a cement clinker manufacturing method according to the present invention using the cement clinker manufacturing apparatus shown in the third embodiment will be described.
As in the first embodiment, the high temperature from the rotary kiln 1 that rises from below as the cement raw material charged into the first-stage cyclone 4a of the preheater 3 falls sequentially to the lower cyclones 4b to 4d. The exhaust gas is preheated and finally introduced into the kiln bottom 2 of the rotary kiln 1 from the chute 5 of the lowermost cyclone 4d.

  At this time, a part of the cement raw material is extracted from the extraction line 6 connected to the chute 5 of the lowermost cyclone 4 d and supplied to the firing furnace 8. Further, the cement raw material is supplied to the pyrolysis furnace 12 from a part of the extracted cement raw material through a heat medium supply line 11 connected to the extraction line 6. At this time, the pyrolysis furnace 12 is pyrolyzed in the pyrolysis furnace 12 by direct contact of the chlorine-containing plastic with the cement raw material. As a result, a pyrolysis gas mainly containing hydrogen chloride and a pyrolysis residue mainly composed of carbide from which most of the halogen has been removed are generated in the pyrolysis furnace 12.

  Then, the cement raw material containing the pyrolysis residue is first sent from the recovery line 15 to the dust cleaning device 31 and washed with water therein, so that the halogen contained in the cement raw material is cleaned and removed. Is done. Next, the cement raw material and the pyrolysis residue that have passed through the dust cleaning device 31 are introduced into the kiln bottom 2 of the rotary kiln 1 from the recovery line 15.

  By the way, also in this 3rd Embodiment, the chlorine content and alkali content which are contained in a cement raw material volatilize in the high temperature (about 1400 degreeC) atmosphere in the rotary kiln 1, and transfer to waste gas. And when this exhaust gas is exhausted from the kiln bottom 2 of the rotary kiln 1 to the pre-heater 3 side and rises sequentially from the lower part to the upper cyclones 4d to 4a, it is cooled by preheating the cement raw material, The chlorine content contained in the material will again move to the cement raw material side.

  As a result, since the chlorine content circulates in the system composed of the rotary kiln 1 and the preheater 3, the internal chlorine concentration gradually rises due to the chlorine content newly introduced into the system from the combustion exhaust gas or the cement raw material. The cyclone of the pre-heater 3 is blocked, and the operation is hindered. For this reason, as shown in FIG. 2, it is possible to prevent the chlorine concentration in the system from increasing by using the chlorine recovery means 16 of the modification of the first embodiment. In this case, the dust cleaning device 31 can be omitted.

  On the other hand, the combustible pyrolysis gas generated in the pyrolysis furnace 12 is supplied into the calcining furnace 21 by the gas supply line 14 after removing halogen such as chlorine in the gas cleaning device 13, Used as part. Further, the pyrolysis gas is supplied to the firing furnace 8 through the pyrolysis gas supply line 28 branched from the cracking gas extraction line 30 as a part of the substance or fuel containing the halogen element.

Further, in the gas cleaning device 13, an alkali component such as calcium hydroxide added from the supply pipe 13 a is brought into contact with the pyrolysis gas discharged from the pyrolysis furnace 12, and chlorine contained in the pyrolysis gas The calcium chloride aqueous solution is supplied via a calcium chloride aqueous solution supply pipe 13d branched from a calcium chloride aqueous solution discharge pipe 13b for discharging the calcium chloride aqueous solution and the like after being removed from the pyrolysis gas as a salt such as calcium chloride. A part is sprayed to the firing furnace 8 as a substance containing a halogen element.

  Then, the cement raw material containing the pyrolysis residue is first sent from the recovery line 15 to the dust cleaning device 31 and washed with water therein, so that the halogen contained in the cement raw material is cleaned and removed. Is done. Next, the cement raw material and the pyrolysis residue that have passed through the dust cleaning device 31 are introduced into the kiln bottom 2 of the rotary kiln 1 from the recovery line 15. Thereby, a cement raw material and a thermal decomposition residue are finally sent to the rotary kiln 1 with other cement raw materials, and are baked. At this time, the combustible component contained in the pyrolysis residue is used as part of the fuel in the calcining furnace 21 or the rotary kiln 1.

  On the other hand, a part of the cement raw material extracted from the chute 5 of the lowermost cyclo 4d is supplied to the firing furnace 8, and a substance containing a halogen element is supplied from a supply line 10 connected to the firing furnace 8. It is supplied to the firing furnace 8. Further, the pyrolysis gas and the calcium chloride aqueous solution are supplied via the pyrolysis gas supply line 28 and the calcium chloride aqueous solution supply pipe 13d.

  Then, a part of the cement raw material supplied to the firing furnace 8 and the substance containing a halogen element, further, the pyrolysis gas and the calcium chloride aqueous solution are continuously heated by the burner provided in the firing furnace 8, Baking is performed at a temperature of 1200 ° C. or higher. By firing the cement raw material at 1200 ° C. or higher, alite is crystallized as the liquid phase of the cement raw material is generated. Then, the cement raw material from which the alite is crystallized is introduced into the kiln bottom 2 of the rotary kiln 1 through a return line 9 connected to the firing furnace 8.

  Thus, the cement raw material introduced into the kiln bottom 2 of the rotary kiln 1 is caused by the combustion exhaust gas from the main burner 19 in the process of being gradually sent from the kiln bottom 2 side to the front kiln 24 side in the rotary kiln 1. It is heated and baked to become a clinker. At this time, since a portion of the cement raw material introduced from the firing furnace 8 has already started to crystallize, this becomes a crystal nucleus and is directly introduced into the rotary kiln 1 from the chute 5 of the lowermost cyclone 4d. Further, the generation of alite as the cement raw material is promoted, and as a result, the calorific value of the cement clinker is reduced. Furthermore, combustible waste containing chlorine can be processed smoothly in a cement clinker manufacturing device, and its calorific value is produced without causing any harmful effects due to chlorine contained in the waste. It can be effectively used as part of the fuel.

According to the cement clinker manufacturing apparatus and method according to the above-described embodiment, when manufacturing the cement clinker, a part of the cement raw material is extracted from the extraction line 6 connected to the chute 5 of the cyclone 4 of the preheater 3. A part of the cement raw material containing a halogen element is extracted and supplied to the firing furnace 8 and fired at 1200 ° C. or higher in the firing furnace 8 to return a part of the cement raw material from the return line 9 to the rotary kiln 1. Is produced at a low temperature to promote the formation of alite contained in the cement raw material, and the cement raw material that has been baked to crystallize alite is returned to the rotary kiln, thereby partially Or all of them become alite crystal nuclei, producing alite from low temperature It is promoted, thereby reducing the sintering heat of cement clinker. This makes it possible to produce a cement clinker even at a relatively low temperature without changing the main chemical composition of the cement raw material, and it can be used for general-purpose Portland cement. Furthermore, when cement clinker is fired in the rotary kiln 1, heat loss can be eliminated, and the length of the rotary kiln can be shortened, leading to reductions in equipment costs, power costs, and maintenance costs.

  In addition, since the firing furnace 8 is provided with a supply line 10 for supplying a substance containing a halogen element, firing of the cement raw material supplied into the firing furnace 8 can be promoted. Thereby, the fuel cost used for the said baking furnace can be held down.

  The firing means 7 is supplied from the heat medium supply line 11 for extracting a part of the cement raw material heated to 250 ° C. or more from the chute 5 of the lowermost cyclone 4 d of the preheater 3 and the heat medium supply line 11. A pyrolysis furnace 12 that directly contacts a halogen-containing material containing halogen to the cemented raw material to generate a combustible gas containing the halogen and a residue, and heats and fires at 1200 ° C. or higher, and pyrolysis A halogen gas cleaning device 13 for recovering the halogen from the combustible gas containing the halogen discharged from the furnace 12, and the combustible gas after the halogen is recovered by the halogen gas cleaning device 13 is supplied to the cement clinker. A gas supply line 14 that is supplied as fuel for the manufacturing apparatus, and the cement material discharged from the pyrolysis furnace 12 And a halogen-containing material fueling system including a recovery line 15 for returning the residue to the kiln bottom of the rotary kiln 1, which is caused by halogen such as chlorine and bromine contained in a part of the cement raw material. It can be easily removed, and can be fired while promoting the generation of alite contained in a part of the cement raw material. As a result, firing of the cement clinker can be promoted in the rotary kiln.

  Furthermore, since the kiln bottom 2 of the rotary kiln 1 is equipped with chlorine recovery means 16 including a chlorine bypass pipe 17 and a bag filter 18 for recovering a part of the exhaust gas, the cement raw material is supplied in the rotary kiln 1, Even when chlorine stays in the rotary kiln 1 when the cement clinker is fired, it can be easily removed and a high-quality cement clinker can be obtained.

  In the above embodiment, only the case where the waste is separated into the chlorine-containing plastic and the low chlorine concentration plastic by the sorting device 25 has been described. However, the present invention is not limited to this, and the sorting device 25 is not installed. Thus, both the chlorine-containing plastic and the low chlorine concentration plastic may be introduced into the pyrolysis furnace 12 without being selected. Furthermore, when the waste to be treated contains a large amount of chlorine-containing plastic, adopting this configuration is preferable because the entire system can be simplified.

  Further, the high-temperature cement raw material and the residue discharged from the pyrolysis furnace 12 are returned from the recovery line 15 to the kiln bottom 2 of the rotary kiln 1, but the present invention is not limited to this. It is possible to return to 4a or a dry mill for mixing cement raw material (not shown) on the upstream side thereof.

  Further, the position for extracting the high-temperature cement raw material is not limited to the above-described chute 5 or the chlorine bypass pipe 17 of the lowermost cyclone 4d, but can be extracted from the upper cyclones 4a to 4c. In particular, when extracted from the upper cyclone 4a and the like, although the temperature is relatively low, since the high-temperature cement raw material has a small amount of salt, the cyclone 4a or the like as it is after being discharged from the pyrolysis furnace 12, It is possible to return to the dry mill or the cement raw material storage facility.

  It can be used for the production of cement clinker.

DESCRIPTION OF SYMBOLS 1 Rotary kiln 2 Kiln bottom 3 Preheater 4 Cyclone 5 Chute 6 Extraction line 7 Firing means 8 Firing furnace 9 Return line 10 Supply line 11 Heat medium supply line (extraction line)
12 Halogen separation means 13 Halogen recovery means 14 Supply line 15 Recovery line (return line)
16 Chlorine recovery means 17 Chlorine bypass pipe 18 Bag filter 19 Main burner 20 Clinker cooler 21 Calciner

Claims (6)

A cement clinker manufacturing apparatus comprising a preheater for preheating the cement raw material using a cement raw material and / or fuel containing a halogen element, and a rotary kiln for firing the cement raw material downstream of the preheater,
An extraction line for extracting a part of the cement raw material from the cyclone chute of the preheater, a baking means for baking the cement raw material extracted from the extraction line, and an alite crystal baked in the baking means. a part of the cement material which issued to and a return line for returning to the rotary kiln apparatus for manufacturing cement clinker according to claim.   2. The cement clinker manufacturing apparatus according to claim 1, wherein the firing means is a firing furnace that fires at a temperature of 1200 ° C. or more and includes a supply line that supplies a substance containing a halogen element. The calcination means is a halogen separation means for generating a flammable gas and a residue containing halogen by directly contacting a halogen-containing substance containing halogen to the cement raw material supplied from the extraction line;
Halogen recovery means for recovering the halogen from the flammable gas containing the halogen discharged from the halogen separation means, and the combustor after the halogen is recovered by the halogen recovery means, the cement clinker manufacturing apparatus 3. The cement clinker manufacturing apparatus according to claim 1, further comprising: a halogen-containing fuel conversion system including a gas supply line that supplies the fuel as a fuel for the first fuel.   The cement clinker manufacturing apparatus according to any one of claims 1 to 3, wherein a chlorine recovery means for recovering a part of the exhaust gas is provided at a kiln bottom of the rotary kiln. A method for producing a cement clinker using the cement clinker apparatus according to claim 1 or 2,
Inside the said firing means is maintained at a temperature atmosphere of more than 1200 ° C., from the chute of the cyclone of the preheater calcined by supplying a part of the cement material, the cement raw materials alite crystallized out by the calcination A method for producing a cement clinker, characterized in that a part is supplied to the rotary kiln. A method for producing a cement clinker using the cement clinker production apparatus according to claim 3,
Part of the cement raw material is supplied and fired from the cyclone chute of the preheater to the halogen separation means whose interior is maintained in a temperature atmosphere of 1200 ° C. or higher, and part of the fired cement raw material is transferred to the rotary kiln. A method for producing a cement clinker, characterized in that the flammable gas after the halogen is collected is supplied as fuel to the cement clinker production apparatus while being supplied by the halogen collecting means.

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