Cement clinker manufacturing method and cement clinker manufacturing apparatus

Abstract

To provide a cement clinker manufacturing apparatus capable of manufacturing cement clinker with high energy efficiency while reducing carbon dioxide emissions by using ammonia.SOLUTION: A cement clinker manufacturing apparatus of the invention includes a calcining furnace 30 and a rotary kiln, wherein the calcining furnace 30 has a first inlet 10 for introducing a thermal energy raw material containing ammonia gas, and burning the ammonia gas in the calcining furnace 30.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a method for producing cement clinker and an apparatus for producing cement clinker. [Background technology]

[0002] A cement clinker manufacturing apparatus produces cement clinker by calcining cement raw materials in a calcination furnace having a rotary kiln. Attempts have been made to supply ammonia to the calcination furnace in addition to fossil fuels such as heavy oil, waste materials, biomass, etc., in order to reduce the amount of carbon dioxide generated. For example, Patent Document 1 proposes a technology in which an ammonia-containing gas containing ammonia and air is injected from a burner unit and combusted in a rotary kiln together with fossil fuels and combustible waste materials such as waste plastics, in order to reduce carbon dioxide emissions. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-172484 Summary of the Invention [Problem to be solved by the invention]

[0004] When producing cement clinker, supplying ammonia to a rotary kiln is effective in reducing carbon dioxide emissions from the rotary kiln. However, supplying ammonia to the rotary kiln can make it difficult to raise the temperature of the cement raw materials in the rotary kiln, which can result in unstable cement clinker properties and increased fuel consumption. Therefore, the present disclosure provides a cement clinker production method and cement clinker production apparatus that use ammonia to reduce carbon dioxide emissions while producing cement clinker with high energy efficiency. [Means for solving the problem]

[0005] In the case of an NSP kiln, cement raw materials are heated in the suspension preheater, calciner, and rotary kiln. At this time, the cement raw materials are heated by thermal conduction, convection, and radiation, but the amount of heat energy emitted by thermal radiation is proportional to 3 to 4 degrees of absolute temperature. For this reason, heat transfer in the high-temperature rotary kiln is mainly by radiation. In contrast, heat transfer in the calciner and suspension preheater, which are at lower temperatures than the rotary kiln, is mainly by convection.

[0006] When comparing flares from fossil fuels (heavy oil, petroleum coke, and coal) alone and from the co-combustion of fossil fuels and ammonia, the radiative heat transfer is small when fossil fuels and ammonia are co-combusted, so when ammonia is used as a thermal energy source for a rotary kiln, the cement raw materials tend to be insufficiently heated.The reason for this is thought to be that when ammonia is burned, the composition of the flue gas changes, reducing the CO2 concentration, which contributes to the emissivity of the flue gas.

[0007] Therefore, the present disclosure provides a method for producing cement clinker using an NSP kiln equipped with a calciner and a rotary kiln, the method including an introduction step of introducing a thermal energy raw material containing ammonia gas from a first inlet provided in the calciner, and a combustion step of burning the ammonia gas in the calciner.

[0008] The temperature of the calciner in an NSP kiln is lower than that of a rotary kiln. Therefore, the proportion of radiative heat transfer in the heat transfer to the cement raw materials is higher in a rotary kiln than in a calciner, and the proportion of convective heat transfer is higher in a calciner than in a rotary kiln. In the above-described production method, ammonia gas is burned in a calciner where the proportion of convective heat transfer is higher than in a cement kiln, allowing for efficient use of ammonia gas as a thermal energy source. By using ammonia gas as a thermal energy source in the calciner in this way, cement clinker can be produced with high energy efficiency while reducing carbon dioxide emissions. Furthermore, if some of the ammonia gas is unburned, denitrification can also reduce the nitrogen oxides contained in the exhaust gas.

[0009] In the above-described manufacturing method, the thermal energy raw material introduced from the first inlet in the introducing step preferably contains solids, thereby ensuring a sufficient amount of heat to sufficiently heat the cement raw material in the calciner.

[0010] The above-mentioned production method includes a transport step of transporting the solid content by a gas containing ammonia gas, and in the introduction step, the solid content is preferably discharged into the calciner from the first inlet by the pressure of the ammonia gas. This improves energy efficiency compared to transporting the solid content using excess air or nitrogen or other gases that do not contribute to combustion as a carrier gas.

[0011] The above manufacturing method preferably includes a denitration step of introducing ammonia gas from a second inlet provided in the exhaust gas flow path downstream of the first inlet relative to the flow direction of the exhaust gas to denitrify the exhaust gas. By introducing ammonia gas from the second inlet provided downstream of the first inlet, the ammonia gas is supplied to a low-temperature region, thereby promoting the denitration reaction rather than the ammonia combustion reaction. This allows the denitration of nitrogen oxides to proceed efficiently. Therefore, the nitrogen oxides contained in the exhaust gas can be sufficiently reduced. Furthermore, the amount of ammonia used for denitration can also be reduced.

[0012] In the above-described production method, it is preferable that the thermal energy raw material containing ammonia gas introduced through the first inlet is continuously supplied during operation of the calciner, thereby making it possible to sufficiently reduce carbon dioxide emissions and stably reduce nitrogen oxides contained in the exhaust gas.

[0013] The present disclosure provides a cement clinker manufacturing apparatus including a calciner and a rotary kiln, wherein the calciner has a first inlet for introducing a thermal energy raw material containing ammonia gas, and the ammonia gas is burned in the calciner.

[0014] In the cement clinker production apparatus, ammonia gas is burned in a calciner, which has a higher rate of convective heat transfer than a cement kiln, and therefore ammonia gas can be efficiently used as a thermal energy source. By burning ammonia gas in the calciner in this way, cement clinker can be produced with high energy efficiency while reducing carbon dioxide emissions. Furthermore, if some of the ammonia gas is unburned, nitrogen oxides contained in the exhaust gas can be reduced by denitrification.

[0015] The thermal energy raw material introduced from the first inlet of the cement clinker production apparatus preferably contains solids, thereby ensuring a sufficient amount of heat to sufficiently heat the cement raw material in the calciner.

[0016] The cement clinker manufacturing apparatus preferably has a conveying section that conveys the solids using a gas containing ammonia gas, and discharges the solids from the first inlet into the calciner using the pressure of the ammonia gas. This improves energy efficiency compared to conveying the solids using excess air, nitrogen, or other gases that do not contribute to combustion as a carrier gas.

[0017] The cement clinker manufacturing apparatus preferably has a second inlet for introducing ammonia gas into the flue gas flow path downstream of the first inlet when the flue gas flow direction is taken as the reference, and denitrifies the combustion flue gas using the ammonia gas introduced from the second inlet. By having the second inlet for introducing ammonia gas into the flue gas flow path downstream of the first inlet, the ammonia gas is supplied to a lower temperature range than the first inlet. This promotes the denitrification reaction more than the combustion reaction of ammonia, and the denitrification of nitrogen oxides proceeds efficiently. Therefore, the nitrogen oxides contained in the flue gas can be sufficiently reduced. In addition, the amount of ammonia used for denitrification can also be reduced. [Effects of the Invention]

[0018] It is possible to provide a cement clinker manufacturing method and cement clinker manufacturing apparatus that can manufacture cement clinker with high energy efficiency while reducing carbon dioxide emissions by using ammonia. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a diagram schematically illustrating an embodiment of a cement clinker manufacturing apparatus. FIG. [Figure 2] FIG. 2 is an enlarged view showing an example of a calciner and its vicinity. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings as needed. However, the following embodiments are merely examples for explaining the present disclosure and are not intended to limit the present disclosure to the following content. In the description, the same elements or elements having the same functions will be designated by the same reference numerals, and redundant explanations will be omitted where appropriate. Furthermore, unless otherwise specified, positional relationships such as up, down, left, and right will be based on the positional relationships shown in the drawings. Furthermore, the dimensional ratios of each element are not limited to those shown in the drawings.

[0021] 1 is a diagram schematically illustrating one embodiment of a cement clinker production apparatus. The cement clinker production apparatus 100 is an apparatus also known as an NSP kiln (NSP: New Suspension Preheater Kiln). The cement clinker production apparatus 100 includes four cyclones C1, C2, C3, and C4 (preheaters) that preheat the cement raw materials, a calciner 30 that calcines the cement raw materials, a rotary kiln 40 that burns the preheated and calcined cement raw materials to produce cement clinker, and a clinker cooler 50 that cools the cement clinker produced in the rotary kiln 40 and discharges the cooled cement clinker.

[0022] The kiln end 42 of the rotary kiln 40 and the calciner 30 are connected by a rising duct 34. A probe 36 is connected to the rising duct 34, which extracts the kiln exhaust gas from the rising duct 34. A chlorine bypass system (not shown), which includes a cooler, a bag filter, and the like, is installed downstream of the probe 36, and dust contained in the extracted gas (kiln exhaust gas) extracted by the probe 36 is recovered. The inclusion of such a chlorine bypass system makes it possible to reduce volatile components such as chlorine compounds and alkalis from within the cement clinker production apparatus 100. In a modified example, the probe 36 may be connected to the kiln end 42 or to the boundary between the rising duct 34 and the kiln end 42.

[0023] The cement raw material may contain, for example, two or more selected from the group consisting of incineration ash, coal ash, limestone, an iron source, and slag. Such cement raw material is introduced from the connection between cyclone C1 and cyclone C2, heated while flowing through cyclone C1, cyclone C2, cyclone C3, rising duct 34, calciner 30, and cyclone C4, and introduced into the kiln end 42 of rotary kiln 40. When introduced into the kiln end 42, the cement raw material has been heated to, for example, 850 to 1000°C, preferably 850 to 900°C.

[0024] In the rotary kiln 40, the preheated and calcined cement raw materials are heated by combustion in a burner 44 provided at one end of the rotary kiln 40 to form cement clinker. The cement clinker produced in the rotary kiln 40 may be cooled in a clinker cooler 50 by cooling air such as dust-removed flue gas and outside air discharged from the chlorine bypass facility. After being cooled in the clinker cooler 50, the cement clinker is discharged from the cement clinker production apparatus 100.

[0025] The rotary kiln 40 is equipped with a burner 44 that burns fuel on the clinker cooler 50 side. Combustion by the burner 44 heats the cement raw materials in the rotary kiln 40 to, for example, 1300 to 1450°C. Due to such high-temperature conditions, it is preferable that the cement raw materials be heated by radiant heat transfer rather than convective heat transfer. In the rotary kiln 40, the contribution rate of radiant heat transfer to the total heat transfer to the cement raw materials may be, for example, 60% or more, or even 70% or more. By setting operating conditions in the rotary kiln 40 that increase the contribution rate of radiant heat transfer, it is possible to improve energy efficiency.

[0026] From this perspective, the thermal energy raw material burned in the burner 44 preferably includes a fossil fuel containing carbon. Examples of fossil fuels include heavy oil, petroleum coke, and coal (pulverized coal). Using a fossil fuel increases the concentration of carbon dioxide contained in the combustion exhaust gas, thereby sufficiently increasing the contribution rate of radiant heat transfer. The burner 44 may burn ammonia as the thermal energy raw material, or multiple burners 44 may be provided and fossil fuel and ammonia gas may be introduced separately. However, if the amount of ammonia gas introduced into the rotary kiln 40 increases, the concentration of carbon dioxide in the combustion exhaust gas decreases, reducing the contribution rate of radiant heat transfer, which tends to reduce energy efficiency.

[0027] From the viewpoint of sufficiently increasing energy efficiency, it is preferable that the amount of ammonia introduced into the rotary kiln 40 is small. For example, it is preferable that the amount of ammonia introduced into the rotary kiln 40 is smaller than the amount of ammonia introduced into the calciner 30. It is also possible that ammonia is not introduced into the rotary kiln 40. It is also possible to introduce ammonia gas as a thermal energy source when starting up the rotary kiln 40 after a period of idleness. When starting up such operation, it is necessary to increase the temperature, which tends to increase the amount of fossil fuel consumed compared to steady operation, and therefore increases the amount of sulfur oxides (SOx). Therefore, the SOx concentration can be reduced by introducing ammonia gas from the burner 44, for example.

[0028] Kiln exhaust gas, including combustion exhaust gas, generated in the rotary kiln 40 passes through the kiln end 42 and the rising duct 34 and is introduced into the calciner 30. As shown in FIG. 2 , the calciner 30 is provided with a first inlet 10 for introducing a thermal energy raw material containing an ammonia-containing gas and solids (solid thermal energy raw material) into the calciner 30.

[0029] The first inlet 10 is provided at the tip of the conveying section 12. In the conveying section 12, which is made up of a tubular member, an ammonia-containing gas containing ammonia gas flows toward the first inlet 10 while carrying solid content. From the first inlet 10, a thermal energy raw material containing the ammonia-containing gas and solid content is discharged into the calciner 30. As a result, the ammonia gas and solid content are combusted in the calciner 30, and the cement raw material is heated. Examples of the solid content include pulverized coal, waste plastics, and / or waste including municipal waste.

[0030] The ammonia-containing gas may contain only ammonia gas, or may be a mixed gas of ammonia gas with air, methane, or other gases. By using the ammonia-containing gas as a carrier gas for the solid content, the amount of gas introduced that does not contribute to combustion (for example, at least a portion of the high-pressure air used for transportation) can be reduced. This can further improve the energy efficiency of the cement clinker production apparatus 100. The supply pressure of the ammonia-containing gas to the transport section 12 may be, for example, 0.1 to 0.3 MPa, from the viewpoint of smoothly transporting the solid content.

[0031] It is not essential to introduce the solid content through the first inlet 10. For example, only the ammonia-containing gas may be introduced through the first inlet. In this case, it is preferable to introduce the ammonia gas and the combustion air through the first inlet.

[0032] The temperature inside the calciner 30 is, for example, 850 to 1000°C, preferably 850 to 900°C, which is lower than the temperature inside the rotary kiln 40. Therefore, the proportion of heat transfer by radiation when heating the cement raw materials in the calciner 30 is lower than in the rotary kiln 40, and the proportion of heat transfer by convection in the calciner 30 is high. Therefore, even if at least a portion of the carbon-containing fossil fuel in the calciner 30 is replaced with ammonia, high energy efficiency can be sufficiently maintained. Furthermore, carbon dioxide emissions can be sufficiently reduced.

[0033] A burner for burning a thermal energy feedstock containing an ammonia-containing gas and solids may be provided at the tip of the transport section 12. This allows the ammonia to be burned quickly. It is not necessary to introduce the ammonia-containing gas and solids together into the calciner 30. In a modified example, the ammonia-containing gas may be introduced through the first inlet 10, and the solids may be introduced through a separate inlet. The calciner 30 may be provided with one or more inlets other than the first inlet 10. Materials other than the ammonia-containing gas and solids may be introduced through such inlets. For example, waste materials such as waste plastics and municipal solids, sludge (sewage sludge, organic sludge, blended sludge), and meat and bone meal may be introduced as substitutes for the thermal energy feedstock.

[0034] A part of the ammonia-containing gas introduced from the first inlet 10 may be used as a thermal energy source, and another part may be used for denitration. That is, the reaction may take place not only as shown in the following formula (1) but also as shown in formula (2). NH3 + 1 / 4O2 → 1 / 2N2 + 3 / 2H2O (1) NH3 + NO + 1 / 4O2 → N2 + 3 / 2H2O (2)

[0035] Above 800°C, the combustion reaction (Equation (1)) becomes dominant, while below 800°C, the denitration reaction (Equation (2)) becomes dominant. Because the calciner 30 is in a temperature range where both the combustion reaction and the denitration reaction can proceed, both the ammonia combustion reaction and the denitration reaction can occur. This makes it possible to reduce emissions of both carbon dioxide and nitrogen oxides.

[0036] The ammonia contained in the ammonia-containing gas introduced from the first inlet 10 may undergo both combustion and denitration in the calciner 30, or all or most of the ammonia from the first inlet 10 may be used in the combustion reaction, and the ammonia used in the denitration reaction may be introduced from the second inlet 20. The ammonia-containing gas introduced from the second inlet 20 may contain only ammonia, or may be a mixed gas of ammonia gas and another gas.

[0037] The kiln exhaust gas introduced into the calciner 30 from the rising duct 34 rises while being mixed with the combustion exhaust gas of ammonia and other thermal energy raw materials, and flows together with the cement raw materials through a connection 38 connected to the top of the calciner 30. The connection 38 is a flow path for the exhaust gas accompanying the cement raw materials, connecting the calciner 30 to the cyclone C4 shown in FIG. 1. Based on the flow direction of the exhaust gas, the second inlet 20 is located downstream of the first inlet 10. This allows the second inlet 20 to introduce the ammonia-containing gas into a lower temperature range (e.g., a range below 800°C) than the first inlet 10. This allows the denitrification reaction of formula (1) by the ammonia introduced through the second inlet 20 to be sufficiently promoted.

[0038] In this embodiment, the second inlet 20 is provided in the connection part 38, but is not limited thereto. For example, the second inlet 20 may be provided in the calciner 30, or may be provided in any of the cyclones C1 to C4 or the connection parts therebetween. It is not essential that all of the ammonia contained in the ammonia-containing gas introduced from the second inlet 20 be consumed in the denitration reaction of the above formula (2), and a portion of the ammonia may be combusted as shown in the above formula (1).

[0039] The exhaust gas carrying the cement raw material with sufficiently reduced nitrogen oxides flows through the connection part 38 and is introduced into the cyclone C4, where it is separated from the cement raw material. The cement raw material is then preheated by heat exchange and flows through the cyclones C3, C2, and C1 in this order. The exhaust gas then passes through any exhaust gas treatment facility and may be released into the atmosphere or used for other purposes. From the viewpoint of sufficiently reducing the nitrogen oxides contained in the exhaust gas, it is preferable to continuously supply ammonia to the calciner 30 from at least one of the first inlet 10 and the second inlet 20 during operation of the calciner 30. From the viewpoint of sufficiently reducing both the emissions of nitrogen oxides and carbon dioxide, it is preferable to continuously supply a thermal energy raw material containing ammonia gas from the first inlet 10 during operation of the calciner 30. This allows for a stable reduction in the nitrogen oxides contained in the exhaust gas while also sufficiently reducing the emissions of carbon dioxide.

[0040] A method for producing cement clinker according to one embodiment uses a cement clinker production apparatus 100. That is, in the production method of this embodiment, cement clinker is produced using the cement clinker production apparatus 100, which includes a calciner 30 and a rotary kiln 40. This production method includes a transport step of transporting solid content, which is a part of the thermal energy raw material, by an ammonia-containing gas in a transport section 12, an introduction step of introducing the thermal energy raw material containing the ammonia-containing gas and the solid content from a first inlet 10 provided in the calciner 30, a combustion step of burning ammonia gas in the calciner 30, and a denitrification step of denitrifying exhaust gas by introducing ammonia gas from a second inlet 20.

[0041] Each step can be performed based on the above-described description of the cement clinker production apparatus 100. Therefore, the description of the cement clinker production apparatus 100 also applies to the cement clinker production method of this embodiment. In the introducing step, the solid content may be discharged from the first inlet 10 into the calciner 30 by the pressure of the ammonia-containing gas. This reduces the amount of excess high-pressure conveying air used that does not contribute to combustion, and further improves energy efficiency.

[0042] According to the cement clinker manufacturing apparatus 100 and the cement clinker manufacturing method according to the above-described embodiments, as well as their modified examples, it is possible to reduce carbon dioxide emissions by using ammonia as a thermal energy raw material for the calciner 30. Furthermore, it is possible to stably heat the cement raw materials with high energy efficiency and to manufacture cement clinker with sufficiently suppressed variation in properties.

[0043] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments. For example, the method for producing cement clinker may be performed using a cement clinker production apparatus other than the cement clinker production apparatus 100. In the cement clinker production apparatus, the number of cyclones that preheat the cement raw materials is not particularly limited, and may be three or less, or five or more. [Example]

[0044] The present disclosure will be described in detail below with reference to reference examples.

[0045] (Reference example 1) A cement clinker manufacturing plant as shown in Figure 1 was operated to produce cement clinker from cement raw materials. Only pulverized coal was burned in the burners installed in the rotary kiln. The temperature distribution inside the rotary kiln during this operation was investigated.

[0046] As a result, the temperature of the cement raw materials introduced into the rotary kiln increased from the end of the kiln toward the burner side. The temperature of the cement raw materials at the end of the kiln was approximately 900°C, and reached a high temperature of over 1400°C near the burner.

[0047] Heat transfer to cement raw materials in a rotary kiln involves three processes: radiation from the gas to the surface of the solids (cement raw materials), convection from the gas to the surface of the solids, and radiation from the inner wall of the rotary kiln to the surface of the solids.The heat and mass balance inside the rotary kiln was then solved to estimate the contribution of each process to heat transfer.

[0048] The results showed that the majority of heat transfer within the rotary kiln was radiative, with this proportion increasing as the temperature increased. The contribution of radiative heat transfer (radiation from the gas + radiation from the inner wall surfaces) to the total heat transfer to the solids was approximately 87% at its maximum. Gas radiation accounted for 80-90% of the radiative heat transfer, confirming that radiative heat transfer from the burner flame plays a major role in the generation of cement clinker. Meanwhile, the proportion of convective heat transfer increased as the temperature decreased, and near the end of the kiln the contribution of convective heat transfer to the total heat transfer rose to approximately 38%.

[0049] (Reference example 2) Using a small industrial furnace, a comparison was made between flame (A) when only heavy oil was burned and flame (B) when a mixed fuel of 70% heavy oil and 30% ammonia was burned in terms of calories. As a result, it was confirmed that, even though the total calories of the thermal energy material used for combustion were the same, flame (B) had a smaller luminous flame and lower brightness than flame (A). This also confirmed that co-firing ammonia reduces radiation activity.

[0050] In a calciner, the cement raw materials are heated at a lower temperature than in a rotary kiln. According to the results of Reference Example 1, in the temperature range lower than that in a rotary kiln, the contribution of heat transfer by convection from gas to the surface of the cement raw materials is higher than inside the rotary kiln. Therefore, by using ammonia gas as a thermal energy source in the calciner, energy efficiency can be improved compared to when ammonia gas is used as a thermal energy source only in a rotary kiln. [Industrial Applicability]

[0051] According to the present disclosure, it is possible to provide a cement clinker manufacturing method and cement clinker manufacturing apparatus that are capable of manufacturing cement clinker with high energy efficiency while reducing carbon dioxide by using ammonia. [Explanation of symbols]

[0052] 10...first inlet, 12...conveying section, 20...second inlet, 30...calciner furnace, 34...rising duct, 36...probe, 38...connection section, 40...rotary kiln, 42...kiln bottom, 44...burner, 50...clinker cooler, 100...cement clinker manufacturing apparatus, C1, C2, C3, C4...cyclones.

Claims

1. A method for producing cement clinker using an NSP kiln equipped with a calciner and a rotary kiln, a conveying step of conveying a solid content, which is a solid thermal energy raw material, by a gas containing ammonia gas; an introduction step of introducing a thermal energy raw material containing the ammonia gas and the solid content from a first inlet provided in the calciner; a combustion step of combusting the ammonia gas and the solid content in the calciner, In the introducing step, the solid content is discharged from the first inlet into the calciner by the pressure of the gas.

2. A method for producing cement clinker using an NSP kiln equipped with a calciner and a rotary kiln, comprising: an introduction step of introducing a thermal energy source containing ammonia gas from a first inlet provided in the calciner; a combustion step of burning the ammonia gas in the calciner; and a denitration step of denitrifying the exhaust gas by introducing ammonia gas from a second inlet provided in the exhaust gas flow path downstream of the first inlet when the flow direction of the exhaust gas is used as a reference.

3. A transport process for transporting solids contained in the thermal energy raw material to the first inlet using a gas containing the ammonia gas, The method for producing cement clinker according to claim 2 , wherein in the introducing step, the solid content is discharged from the first inlet into the calciner by the pressure of the gas.

4. The method for producing cement clinker according to any one of claims 1 to 3, wherein the thermal energy raw material containing the ammonia gas introduced from the first inlet is continuously supplied during operation of the calciner.

5. A cement clinker manufacturing apparatus including a calciner and a rotary kiln, The system is equipped with a transport unit that transports solid matter, which is a solid thermal energy raw material, using a gas containing ammonia gas. the calciner has a first inlet through which a thermal energy source containing the ammonia gas and the solid content is introduced, The solid content is discharged from the first inlet into the calciner by the pressure of the gas, and the ammonia gas and the solid content are combusted in the calciner.

6. A cement clinker manufacturing apparatus including a calciner and a rotary kiln, The calciner has a first inlet for introducing a thermal energy source containing ammonia gas; a second inlet that introduces ammonia gas into the exhaust gas flow path downstream of the first inlet when the flow direction of the exhaust gas is taken as the reference, The ammonia gas introduced from the first inlet is burned in the calciner, The cement clinker manufacturing apparatus denitrifies the exhaust gas with the ammonia gas introduced through the second inlet.

7. A conveying section that conveys solids contained in the thermal energy raw material to the first inlet using a gas containing the ammonia gas, The cement clinker manufacturing apparatus according to claim 6, wherein the solid content is discharged from the first inlet into the calciner by the pressure of the gas.

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