JP2018168044A - Method for producing cement clinker, method for producing cement and method for processing organic sludge and sulfur-containing waste - Google Patents

Abstract

To provide a method for producing a cement clinker capable of suppressing generation of coating in a method for producing a cement clinker in which a sulfur-containing waste such as a waste gypsum board is added to a calcination step.SOLUTION: There is provided a method for producing a cement clinker which comprises; a calcination step of calcining a raw material for a cement clinker to produce a cement clinker; a reduction step of reducing a sulfur component contained in a mixture obtained by mixing a sulfur-containing waste and an organic sludge containing anaerobic bacteria for generating hydrogen sulfide from sulfur oxide by fermentation and reducing the water content of the mixture to obtain a reduction mixture; and an adsorption step of adsorbing hydrogen sulfide generated by fermentation in active carbon in the reduction step to obtain adsorbing active carbon. The reduction mixture and the adsorbing active carbon are added to the calcination step.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing a cement clinker, a method for producing a cement, and a method for treating organic sludge and sulfur-containing waste.

  Conventionally, many waste gypsum boards have been landfilled, but recycling to gypsum boards and recycling to cement is desired. For example, Patent Document 1 describes that a crushed waste gypsum board is put into a cement firing step and the waste gypsum board is used as a raw material for cement clinker.

JP 2003-137619 A

  As a result of diligent research, the inventors of the present invention, as described in Patent Document 1, when the crushed waste gypsum board is put into the cement firing process, the generation of coaching in the kiln, the kiln resulting from the coaching, etc. It has been found that problems such as occlusion occur. As a result of further diligent research, the inventors of the present invention have confirmed that the generation of coating in the kiln is caused by the sulfur content contained in the waste gypsum board, and that the waste gypsum board having a reduced concentration of sulfur is used as the cement clinker firing process. It was found that the production of the coaching can be suppressed by introducing it into the (cement clinker production process), and the present invention has been achieved.

  A main object of the present invention is to provide a cement clinker manufacturing method capable of suppressing the generation of coating in a cement clinker manufacturing method in which a sulfur-containing waste such as waste gypsum board is input to a firing step.

  The method for producing a cement clinker according to the present invention is a method for producing a cement clinker including a firing step for producing a cement clinker by firing a raw material of the cement clinker. The method for producing a cement clinker according to the present invention further includes a reduction step and an adsorption step. In the reduction process, sulfur-containing waste and organic sludge containing anaerobic bacteria that generate hydrogen sulfide from sulfur oxide by fermentation are mixed and fermented to reduce the sulfur component contained in the mixture, A reduced mixture is obtained by reducing the water content of the mixture. In the adsorption step, adsorbed activated carbon is obtained by adsorbing hydrogen sulfide generated by fermentation on the activated carbon in the reduction step. Charge the reduced mixture and adsorbed activated carbon into the firing process.

  In the method for producing a cement clinker according to the present invention, the sulfur content of the mixture is reduced by fermentation with anaerobic bacteria performed in the reduction step. For this reason, generation | occurrence | production of coaching is suppressed in a baking process. Therefore, problems such as blockage of a kiln and the like due to coaching are unlikely to occur. That is, since the sulfur-containing waste can be suitably used for the production of a cement clinker while suppressing the generation of coaching, the sulfur-containing waste can be suitably treated.

  Furthermore, fermentation heat is generated by fermentation by anaerobic bacteria in the reduction process. This fermentation heat dries the mixture. For this reason, the mixture thrown into the baking process is a mixture with a reduced moisture concentration. By introducing the mixture having a reduced moisture concentration into the firing step, the amount of heat necessary to remove the moisture contained in the mixture can be reduced, and the mixture can be suitably used as a fuel. In other words, more heat can be obtained from the mixture. Therefore, the fuel required in the firing process can be reduced.

  Further, since the adsorbed activated carbon is introduced into the firing process, the adsorbed activated carbon functions as a fuel in the firing process. Therefore, the amount of fuel to be input can be reduced.

  As described above, in the method for producing a cement clinker according to the present invention, sulfur-containing waste and organic sludge can be suitably treated without adversely affecting a firing device such as a kiln, and the firing step is performed with a small amount of fuel. As a result, the production cost of the cement clinker can be reduced.

  In the method for producing a cement clinker according to the present invention, it is preferable to introduce the adsorbed activated carbon into the firing step so that the sulfur component adsorbed on the adsorbed activated carbon is taken into the cement clinker.

  In the method for producing a cement clinker according to the present invention, it is preferable to introduce the adsorbed activated carbon into the kiln.

  In the method for producing a cement clinker according to the present invention, it is preferable to introduce the adsorbed activated carbon into the kiln through the kiln main burner or auxiliary burner.

  In the method for producing a cement clinker according to the present invention, it is preferable to put the adsorbed activated carbon in an atmosphere of 1400 ° C. or higher.

  In the method for producing a cement clinker according to the present invention, it is preferable to introduce the reduced mixture into at least one of the preheater, the calciner, and the kiln bottom of the kiln in the firing step.

  In the method for producing a cement clinker according to the present invention, the anaerobic bacteria are preferably sulfate-reducing bacteria.

  In the manufacturing method of the cement clinker according to the present invention, in the reduction step, the sulfur-containing waste powder is produced by crushing the sulfur-containing waste, and the sulfur-containing waste powder and the organic sludge are mixed and fermented. preferable.

  In the method for producing a cement clinker according to the present invention, as the sulfur-containing waste, it is preferable to use at least one selected from the group consisting of gypsum board, residue under sifting of building mixed waste, acidic sulfate soil, and sulfuric acid pitch. .

  In the method for producing a cement clinker according to the present invention, the organic sludge preferably contains sewage sludge.

  In the method for producing a cement clinker according to the present invention, it is preferable to perform the reduction step until the moisture content of the organic sludge becomes 40% by mass or less.

  In the method for producing a cement clinker according to the present invention, in the reduction step, it is preferable to ferment the sulfur-containing waste and the organic sludge in a state where they are deposited so that open cells are not formed.

  The cement manufacturing method according to the present invention includes a step of manufacturing a cement clinker by the method of manufacturing a cement clinker according to the present invention and a step of manufacturing a cement from the cement clinker.

  The method for treating organic sludge and sulfur-containing waste according to the present invention includes a reduction step and an adsorption step. In the reduction process, the mixture of organic sludge and sulfur-containing waste is fermented by anaerobic bacteria that generate hydrogen sulfide from sulfur oxides by fermentation, reducing sulfur components contained in the sulfur-containing waste, and organic sludge. To obtain a reduced mixture having a low sulfur content and a low water content. In the adsorption step, adsorbed activated carbon is obtained by adsorbing hydrogen sulfide generated by fermentation on the activated carbon in the reduction step.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the cement clinker which can suppress the production | generation of a coaching can be provided in the manufacturing method of the cement clinker which throws in sulfur-containing wastes, such as a waste gypsum board, to a baking process.

It is a schematic diagram of a part of a cement manufacturing apparatus according to an embodiment of the present invention.

  Hereinafter, an example of the preferable form which implemented this invention is demonstrated. However, the following embodiment is merely an example. The present invention is not limited to the following embodiments.

  FIG. 1 is a schematic view of a part of a cement manufacturing apparatus 1 according to the present embodiment. Specifically, FIG. 1 illustrates a cement clinker baking apparatus 10, a fermentation unit 20, and an adsorption unit 30 in the cement manufacturing apparatus 1.

  As shown in FIG. 1, raw materials are charged into the firing apparatus 10. Here, the input raw material includes a raw material of cement clinker and a fuel consumed in firing described later. As a raw material thrown into the baking apparatus 10, organic sludge etc. are mentioned, for example.

  The raw materials are pulverized and mixed by a raw material pulverizer (raw material mill) (not shown) and then charged into the firing apparatus 10 shown in FIG. Specifically, the raw material is charged into the preheater 11 of the baking apparatus 10. The raw material is preheated by the preheater 11. In addition, it is preferable that the preheater 11 is comprised by the suspension preheater, for example. This is because the preheating efficiency of the raw material can be improved.

  A calcining furnace 12 is connected to the preheater 11. The raw material preheated in the preheater 11 is transferred to the calcining furnace 12. The preheated raw material is thermally decomposed in the calcining furnace 12 maintained in a reducing atmosphere.

  The calcining furnace 12 is connected to a kiln 13 such as a rotary kiln. The raw material thermally decomposed in the calciner 12 is put into the kiln bottom 13a of the kiln 13. The charged raw material is heated by a main burner provided in front of the kiln 13 of the kiln 13 to produce a cement clinker.

  A front kiln 13 of the kiln 13 is connected to a clinker cooler 14. The cement clinker generated in the kiln 13 is cooled in the clinker cooler 14, and the cooled cement clinker is discharged from the clinker cooler 14.

  In the present invention, the baking apparatus used in the baking process may be provided with a kiln and does not necessarily include a preheater or a calcining furnace.

  The manufactured cement clinker is connected to a finishing mill (not shown). In this finishing mill, cement is manufactured by being pulverized and mixed with cement clinker and gypsum, blast furnace slag, fly ash, and the like that play a role in adjusting the hardening rate of the cement.

  As shown in FIG. 1, the cement production apparatus 1 is provided with a fermentation unit 20. The fermentation unit 20 is supplied with a mixture containing sulfur-containing waste and organic sludge.

  Specific examples of the sulfur-containing waste include, for example, gypsum board, residue under sifting of building mixed waste, acidic sulfate soil, sulfuric acid pitch, and the like. Especially, it is preferable to supply the waste gypsum board to which the landfill process etc. are difficult to the fermentation part 20. FIG. Only one of these sulfur-containing wastes may be supplied to the fermentation unit 20, or a plurality of types of sulfur-containing wastes may be supplied.

  Specific examples of organic sludge include, for example, sewage sludge, human waste sludge, food wastewater sludge, sea cucumber, bottom mud, food processing residue, and the like. Specific examples of food processing residues include beer grounds, tea grounds, livestock residues and the like. As will be described later, in the present embodiment, in order to perform fermentation and drying, sewage sludge, human waste sludge, food wastewater sludge, sea urchin sludge, bottom mud and the like having a high water content are supplied to the fermentation unit 20 among the organic sludge. Is preferred.

  In general, in the case of sewage sludge, the moisture content is about 50% by mass to 90% by mass.

  Organic sludge contains anaerobic bacteria that generate hydrogen sulfide from sulfur oxides by fermentation. For example, sewage sludge containing such anaerobic bacteria can be used as organic sludge as it is, and when using organic sludge that does not contain such anaerobic bacteria, Anaerobic bacteria that generate hydrogen sulfide from sulfur oxide may be mixed and used. Since it is not necessary to add anaerobic bacteria, it is more preferable to use sewage sludge containing anaerobic bacteria as the organic sludge.

  The mixture supplied to the fermentation unit 20 may contain raw materials or fuels other than sulfur-containing waste and organic sludge. For example, the mixture may contain garbage, plastics and the like.

  In the fermentation part 20, the mixture containing sulfur-containing waste and organic sludge is fermented by anaerobic bacteria that generate hydrogen sulfide from sulfur oxide by fermentation. Thereby, the sulfur component contained in the mixture is reduced, and the mixture is dried by fermentation heat generated along with the fermentation to reduce the water content of the mixture, thereby obtaining a reduced mixture (reduction step). In the fermentation part 20, the reduced mixture in which the sulfur component content and the moisture content are reduced is input to the firing step. Hereinafter, the mixture in which the sulfur component content and the moisture content are reduced may be referred to as a “reduced mixture”.

  As a bacterium used for fermentation, an anaerobic bacterium is preferably used. Examples of anaerobic bacteria that generate hydrogen sulfide from sulfur oxide by fermentation include sulfate-reducing bacteria. Examples of sulfate-reducing bacteria include eubacteria such as gram-negative bacteria and gram-positive bacteria, archaea, and the like. Specific examples of sulfate-reducing bacteria include, for example, the genus Desulfovibrio, the genus Desulfotocumum. Only one kind of these anaerobic bacteria may be used, or a plurality of kinds may be used.

  It is also conceivable to perform fermentation using aerobic bacteria. However, oxygen is essential for fermentation by aerobic bacteria. For this reason, in order to perform fermentation using aerobic bacteria, vents for introducing oxygen into sulfur-containing waste and organic sludge deposits are formed or mixed periodically to introduce oxygen into the interior. It is necessary to do. Therefore, the fermentation process becomes complicated.

  On the other hand, when an anaerobic bacterium is used as in this embodiment, oxygen is not required, so there is no need to form a vent for introducing oxygen or to stir periodically. . Therefore, by using anaerobic bacteria, the fermentation process can be prevented from becoming complicated, and high fermentation efficiency can be realized.

  From the viewpoint of improving the fermentation efficiency by anaerobic bacteria, the sulfur-containing waste and the like are crushed and powdered, and are preferably mixed well. By doing so, in a reduction process, a mixture can be fermented in the state accumulated so that an open cell may not be formed. For this reason, since it can suppress that oxygen penetrate | invades in the deposited mixture, the fermentation efficiency by anaerobic bacteria can be improved. The sulfur-containing waste or the like is preferably a powder having a maximum particle size of 50 mm or less, and more preferably a powder having a maximum particle size of 30 mm or less. This is because if the particle size of the sulfur-containing waste is large, an aeration path is formed in the deposit, and the fermentation efficiency due to anaerobic bacteria may be reduced.

  In the manufacturing method of the cement clinker of this embodiment, the sulfur content of a mixture is reduced by fermentation by anaerobic bacteria performed in a reduction process. For this reason, generation | occurrence | production of coaching is suppressed in a baking process. Therefore, problems such as blockage of the kiln 13 and the like due to coaching are unlikely to occur. That is, since the sulfur-containing waste can be suitably used for the production of a cement clinker while suppressing the generation of coaching, the sulfur-containing waste can be suitably treated.

  Furthermore, fermentation heat is generated by fermentation by anaerobic bacteria in the reduction process. This fermentation heat dries the mixture. For this reason, the mixture thrown into the baking process is a mixture with a reduced moisture concentration. By introducing the mixture having a reduced moisture concentration into the firing step, the amount of heat necessary to remove the moisture contained in the mixture can be reduced, and the mixture can be suitably used as a fuel. In other words, more heat can be obtained from the mixture. Therefore, the fuel required in the firing process can be reduced. In addition, from the viewpoint of sufficiently reducing the amount of heat necessary for removing water contained in the mixture, the water content of the mixture is preferably 40% by mass or less, and more preferably 30% by mass or less. However, the more the moisture content of the mixture is reduced, the longer it takes to dry the mixture. Therefore, from the viewpoint of not reducing the production efficiency of the cement clinker, the water content of the mixture is preferably 20% by mass or more.

  As described above, in the method for producing a cement clinker according to the present embodiment, sulfur-containing waste and organic sludge can be suitably treated without adversely affecting a firing device such as a kiln, and the firing step is performed with a small amount of fuel. As a result, the production cost of the cement clinker can be reduced.

  Note that the mixture to be fermented may contain, for example, raw garbage having a high water content. Even in that case, the moisture content of the mixture can be effectively reduced by the heat of fermentation. Therefore, the amount of heat required for removing water from the mixture can be reduced.

  The place where the reduced mixture is introduced is not particularly limited. The mixture can be charged into at least one of the preheater 11, the calciner 12, and the kiln 13, for example. Among these, the mixture is preferably charged into at least one of the preheater 11, the calcining furnace 12, and the kiln bottom 13 a of the kiln 13, and more preferably charged into the calcining furnace 12.

  By the way, in this embodiment, anaerobic bacteria which generate hydrogen sulfide by fermentation are used. For this reason, the problem is how to treat the generated hydrogen sulfide.

  In the present embodiment, the adsorbed activated carbon is obtained by adsorbing hydrogen sulfide generated by fermentation on the activated carbon in the reduction step. Specifically, the adsorption unit 30 is connected to the fermentation unit 20. Activated carbon is disposed in the adsorption unit 30. Hydrogen sulfide contained in the exhaust gas from the fermentation unit 20 is adsorbed by the activated carbon in the adsorption unit 30 to generate adsorbed activated carbon. The adsorbed activated carbon is put into the firing process. For this reason, the adsorption activated carbon used for the treatment of hydrogen sulfide is used as a fuel. Therefore, the amount of fuel required for the firing process can be reduced. Therefore, the manufacturing cost of cement clinker can be reduced.

  It is preferable to introduce the adsorbed activated carbon into the firing step so that the sulfur component adsorbed on the adsorbed activated carbon is taken into the cement clinker. In this case, since the generated sulfur component (sulfur oxide) is taken into the raw material of the cement clinker, damage to the firing equipment due to the sulfur component can be suppressed.

  In order to make it easy for the sulfur component adsorbed on the adsorbed activated carbon to be taken in by the cement clinker raw material, it is preferable to put the adsorbed activated carbon in a high temperature atmosphere of, for example, 1400 ° C. or higher. Specifically, it is preferable to put into the kiln, and it is particularly preferable to put into the kiln through the kiln main burner or auxiliary burner. The auxiliary burner refers to a burner for introducing auxiliary fuel installed in the vicinity of the main burner. In the vicinity of the kiln, especially in the kiln main burner, the oxygen concentration of the atmosphere is high, so when adsorbed activated carbon is put into the kiln, especially the kiln main burner, the sulfur component adsorbed on the activated carbon exists as calcium sulfate, Sulfur oxide is not easily generated. Therefore, it can suppress more effectively that a baking apparatus is damaged with a sulfur oxide.

1: Manufacturing apparatus 10: Baking apparatus 11: Preheater 12: Calciner 13: Kiln 13a: Kiln bottom 13b: In front of kiln 14: Clinker cooler 20: Fermenting section 30: Adsorption section

Claims (14)

A method for producing a cement clinker comprising a firing step of producing a cement clinker by firing a raw material of the cement clinker,
By mixing and fermenting sulfur-containing waste and organic sludge containing anaerobic bacteria that generate hydrogen sulfide from sulfur oxides by fermentation, the sulfur component contained in the mixture is reduced, and A reduction step of obtaining a reduced mixture by reducing the moisture content;
In the reduction step, an adsorption step of obtaining adsorbed activated carbon by adsorbing hydrogen sulfide generated by fermentation onto activated carbon;
Further comprising
A method for producing a cement clinker, wherein the reduced mixture and the adsorbed activated carbon are added to the firing step.   The method for producing a cement clinker according to claim 1, wherein the adsorbed activated carbon is introduced into the firing step so that a sulfur component adsorbed on the adsorbed activated carbon is taken into the cement clinker.   The manufacturing method of the cement clinker of Claim 2 which throws the said adsorption | suction activated carbon into a kiln.   The method for producing a cement clinker according to claim 3, wherein the adsorbed activated carbon is charged into a main burner or an auxiliary burner of the kiln.   The manufacturing method of the cement clinker as described in any one of Claims 2-4 which throws in the said adsorbent charcoal in 1400 degreeC or more atmosphere.   The method for producing a cement clinker according to any one of claims 1 to 5, wherein in the firing step, the reduced mixture is introduced into at least one of a preheater, a calciner, and a kiln bottom of a kiln.   The method for producing a cement clinker according to any one of claims 1 to 6, wherein the anaerobic bacterium is a sulfate-reducing bacterium.   The said reduction | restoration process WHEREIN: The sulfur containing waste powder is produced by crushing the said sulfur containing waste, the said sulfur containing waste powder and the said organic sludge are mixed and fermented. The method for producing a cement clinker according to one item.   The said sulfur containing waste uses at least 1 type selected from the group which consists of gypsum board, the residue under a sieve of a building mixed waste, an acidic sulfate soil, and a sulfuric acid pitch, It is any one of Claims 1-8 used. Manufacturing method for cement clinker.   The method for producing a cement clinker according to any one of claims 1 to 9, wherein the organic sludge includes sewage sludge.   The manufacturing method of the cement clinker as described in any one of Claims 1-10 which performs the said reduction process until the moisture content of the said organic sludge becomes 40 mass% or less.   The manufacturing method of the cement clinker as described in any one of Claims 1-11 which ferments the said sulfur containing waste and the said organic sludge in the said reduction process in the state accumulated so that an open cell may not be formed. A step of producing a cement clinker by the method for producing a cement clinker according to any one of claims 1 to 12,
Producing cement from the cement clinker;
A method for producing cement, comprising: A method for treating organic sludge and sulfur-containing waste,
The mixture of organic sludge and sulfur-containing waste is fermented by anaerobic bacteria that generate hydrogen sulfide from sulfur oxide by fermentation, and the sulfur component contained in the sulfur-containing waste is reduced and the water content of the organic sludge is reduced. A reduction step of reducing the rate and obtaining a reduced mixture having a low content of sulfur and a low water content;
In the reduction step, an adsorption step of obtaining adsorbed activated carbon by adsorbing hydrogen sulfide generated by fermentation onto activated carbon;
A method for treating organic sludge and sulfur-containing waste.

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