JP7760672B2 - Cement clinker manufacturing method - Google Patents

Description

This disclosure relates to a method for producing cement clinker and an apparatus for producing cement clinker.

Patent Document 1 discloses a method for producing cement clinker using an NSP kiln equipped with a calciner and a rotary kiln. This production method includes an introduction step of introducing a thermal energy source containing ammonia gas through a first inlet provided in the calciner, and a combustion step of burning the ammonia gas in the calciner.

JP 2023-28050 A

This disclosure provides a method and apparatus for producing cement clinker that are useful for suppressing CO generation due to incomplete combustion of solids when ammonia is supplied to a calciner.

[1] A method for producing cement clinker, comprising: a first supply step of supplying a thermal energy source containing solids using one or more first supply members to the interior of a calciner into which exhaust gas from a rotary kiln that heats cement raw materials to produce cement clinker is introduced; and a second supply step of supplying ammonia using one or more second supply members to the interior of the calciner, wherein, based on the gas flow inside the calciner, the position from which the one or more second supply members supply the ammonia is located upstream of the position from which the one or more first supply members supply the thermal energy source containing solids, and the ratio of the calciner's calorific value to the total calorific value of the thermal energy source supplied to the calciner from the one or more first supply members and the one or more second supply members is 0.01 to 0.90.

[2] The method for producing cement clinker described in [1] above, wherein in the second supplying step, the ammonia is supplied to the interior of the calciner together with air having an air ratio of 0.1 to 1.0.

[3] The method for producing cement clinker described in [1] or [2] above, wherein the solid content is pulverized coal, and the air-dry proximate analysis values of the pulverized coal are: volatile matter 25-35% by mass, moisture 2-4% by mass, fixed carbon 40-60% by mass, and ash 10-25% by mass; and the air-dry chemical analysis values of the pulverized coal are: C (carbon) 60-75% by mass, H (hydrogen) 3-5% by mass, O (oxygen) 6-9% by mass, N (nitrogen) 1-3% by mass, and S (sulfur) 0.1-1.0% by mass; and the calorific value of the pulverized coal is 4500-6500 kcal/kg.

[4] The method for producing cement clinker described in any one of [1] to [3] above, wherein the solid content is pulverized coal, and the particle size distribution of the pulverized coal is such that particles having a particle size of 8.00 μm or more and less than 16.00 μm account for 5 to 20 mass% of particles, particles having a particle size of 16.00 μm or more and less than 32.00 μm account for 20 to 40 mass% of particles, particles having a particle size of 32.00 μm or more and less than 64.00 μm account for 20 to 40 mass% of particles, and particles having a particle size of 64.00 μm or more and less than 128.00 μm account for 10 to 30 mass% of particles.

[5] The method for producing cement clinker described in any one of [1] to [4] above, further comprising a third supply step of supplying a hot gas containing oxygen to the interior of the calciner using one or more third supply members, wherein the temperature of the hot gas is 700°C to 1000°C, and the position from which the one or more third supply members supply the hot gas, based on the gas flow inside the calciner, corresponds to the position from which the one or more first supply members supply the thermal energy source containing the solids, or is located upstream of the supply position, and the one or more second supply members are located downstream of the position from which the ammonia is supplied.

[6] The method for producing cement clinker described in [5] above, wherein in the third supply step, extracted gas from a clinker cooler that cools the cement clinker produced in the rotary kiln is supplied as the hot gas.

[7] The method for producing cement clinker described in any one of [1] to [6] above, wherein the ratio of the calorific value of the ammonia supplied from the one or more second supply members to the calciner to the total calorific value is 0.01 to 0.55, and the ratio of the calorific value of the solid-containing thermal energy source supplied from the one or more first supply members to the calciner to the total calorific value is 0.45 to 0.99.

[8] A cement clinker manufacturing apparatus comprising: a rotary kiln that heats cement raw materials to produce cement clinker; a calciner that receives exhaust gas from the rotary kiln and heats the cement raw materials; one or more first supply members that supply a thermal energy source containing solids to the interior of the calciner; and one or more second supply members that supply ammonia to the interior of the calciner, wherein, based on the gas flow inside the calciner, the position at which the one or more second supply members supply the ammonia is located upstream of the position at which the one or more first supply members supply the thermal energy source containing solids; and the ratio of the calciner's calorific value to the total calorific value of the thermal energy source supplied to the calciner from the one or more first supply members and the one or more second supply members is 0.01 to 0.90.

This disclosure provides a cement clinker manufacturing method and cement clinker manufacturing apparatus that are useful for suppressing CO generation due to incomplete combustion of solids when ammonia is supplied to a calciner.

FIG. 1 is a schematic diagram showing an example of a cement clinker manufacturing apparatus. FIG. 2 is a side view schematically illustrating an example of a calciner and its peripheral members. FIG. 3 is a side view schematically illustrating an example of the supply member. FIG. 4 is a diagram illustrating a simulation result according to a reference example. FIG. 5 is a diagram illustrating a simulation result according to the embodiment. FIG. 6 is a diagram illustrating a simulation result according to the embodiment. FIG. 7 is a diagram illustrating a simulation result according to the example. FIG. 8 is a diagram illustrating a simulation result according to the example. FIG. 9 is a diagram illustrating a simulation result according to the comparative example. FIG. 10 is a diagram illustrating a simulation result according to the comparative example. FIG. 11 is a diagram illustrating a simulation result according to the comparative example. FIG. 12 is a diagram illustrating a simulation result according to the comparative example. FIG. 13 is a graph illustrating the simulation results. FIG. 14 is a graph illustrating the simulation results.

One embodiment will now be described with reference to the drawings. In the description, identical elements or elements with identical functions will be assigned the same reference numerals, and duplicate explanations will be omitted. The following embodiment is an example for explaining the present disclosure, and is not intended to limit the present disclosure to the following content. Furthermore, the dimensional proportions of each element are not limited to those shown in the drawings.

[Cement clinker manufacturing equipment]
FIG. 1 schematically illustrates a cement clinker manufacturing apparatus according to one embodiment. The manufacturing apparatus 100 (cement clinker manufacturing apparatus) illustrated in FIG. 1 is an apparatus that manufactures cement clinker, an intermediate cement product, by burning cement raw materials. The manufacturing apparatus 100 is equipped with a preheating device of the NSP (New Suspension Preheater) type. The manufacturing apparatus 100 is also referred to as an NSP kiln. The manufacturing apparatus 100 includes, for example, cyclones C1, C2, C3, and C4, a calciner 30, a rotary kiln 40, and a clinker cooler 48.

Cyclones C1, C2, C3, and C4 and the calciner 30 function as preheaters that preheat and calcinate the cement raw materials. The cement raw materials may include, for example, two or more selected from the group consisting of incineration ash, coal ash, limestone, an iron source, and slag. The cement raw materials are introduced from the connection between cyclones C1 and C2, heated while flowing through cyclones C1, C2, C3, the calciner 30, and C4, and then introduced into the kiln end 42 of the rotary kiln 40. When introduced into the kiln end 42 of the rotary kiln 40, the cement raw materials are heated, for example, to 850°C to 1000°C, preferably 850°C to 900°C.

The calciner 30 and the kiln end 42 of the rotary kiln 40 are connected by a rising duct 34. Exhaust gas from the rotary kiln 40 is introduced into the calciner 30 via the rising duct 34. The exhaust gas generated in the rotary kiln 40 includes combustion exhaust gas. The exhaust gas from the rotary kiln 40 flows through the calciner 30, cyclone C4, cyclone C3, cyclone C2, and cyclone C1, and heat exchange takes place between the exhaust gas and the cement raw materials.

The calciner 30 calcines the cement raw materials using exhaust gas from the rotary kiln 40 and a thermal energy source supplied to the calciner 30. In other words, the calciner 30 is a heating furnace that heats the cement raw materials. At least a portion of the calciner 30 is cylindrical (see also Figure 2). In at least a portion of the calciner 30, the sidewall of the calciner 30 may extend around the central axis of the calciner 30. The central axis of the calciner 30 is an imaginary line, for example, a line extending vertically.

A probe 36 is connected to the rising duct 34, which extracts the exhaust gas from the rising duct 34. A chlorine bypass system including a cooler and bag filter is installed downstream of the probe 36, and dust contained in the extracted gas (exhaust gas) extracted by the probe 36 is recovered. By installing the chlorine bypass system, volatile components such as chlorine compounds and alkalis can be reduced from within the manufacturing apparatus 100. The probe 36 may be connected to the kiln end 42 instead of the rising duct 34, or to the boundary between the rising duct 34 and the kiln end 42.

The rotary kiln 40 burns cement raw materials to produce cement clinker (hereinafter sometimes simply referred to as "clinker"). In other words, the rotary kiln 40 is a heating furnace that heats the cement raw materials. The rotary kiln 40 is equipped with a burner 44 that burns fuel. The burner 44 is located at the downstream end of the rotary kiln 40 (the end closest to the clinker cooler 48). The combustion in the burner 44 heats the cement raw materials within the rotary kiln 40 to, for example, 1300°C to 1450°C. In the rotary kiln 40, the cement raw materials that have been preheated and calcined are heated by the combustion in the burner 44 to become clinker.

The clinker produced in the rotary kiln 40 is discharged to the clinker cooler 48. The clinker cooler 48 cools the clinker using cooling air, such as outside air. After being cooled in the clinker cooler 48, the clinker is discharged from the manufacturing apparatus 100. A portion of the gas used to cool the clinker in the clinker cooler 48 may be introduced into the calciner 30 as bleed gas. The temperature of the bleed gas introduced from the clinker cooler 48 into the calciner 30 may be 700°C to 1000°C, or 800°C to 900°C. The introduction of a thermal energy source into the calciner 30 is described below.

<Introduction of thermal energy source>
FIG. 2 schematically shows a portion for introducing a thermal energy source into the calciner 30. The manufacturing apparatus 100 includes a thermal energy source supply unit 50. The thermal energy source supply unit 50 supplies two or more types of thermal energy sources. From the viewpoint of reducing carbon dioxide emissions, ammonia (ammonia gas) is introduced into the calciner 30 as one type of thermal energy source. In addition to the calciner 30, ammonia (ammonia gas) may be introduced into the rotary kiln 40 as one type of thermal energy source. Ammonia gas is burned in the calciner 30. In FIG. 2 and other figures, the "Z" axis direction represents the vertical direction, and "S" represents the internal space of the calciner 30.

The thermal energy source supply unit 50 has one or more supply members 60 (first supply members). In the example shown in FIG. 2, two supply members 60 are provided. The supply members 60 are members (burners) that supply a thermal energy source containing solid content to the interior of the calciner 30. Solid content refers to a solid thermal energy source. The supply members 60 may supply solid content and combustion air to the interior of the calciner 30.

The solid content includes, for example, at least one of pulverized coal and waste. The waste supplied to the interior of the calciner 30 may include one or more types of waste, such as waste plastic, RDF (Refuse Derived Fuel), or meat and bone meal. The supply member 60 may supply pulverized coal and combustion air, waste and combustion air, or pulverized coal, waste, and combustion air.

The end of the supply member 60 is provided with an inlet 62 that discharges (blows) solids (e.g., pulverized coal) and combustion air into the calciner 30. The end of the supply member 60 that includes the inlet 62 functions as a nozzle. The end of the supply member 60 that functions as a nozzle may be installed horizontally. Figure 3 shows an enlarged schematic view of the portion marked III in Figure 2. As shown in Figure 3, the end of the supply member 60 may be connected to the side wall of the calciner 30.

The supply member 60 may transport the solids to its inlet 62 using conveying air. The supply member 60 may separately supply the solids (solids and conveying air) and the combustion air to the interior of the calciner 30. In this case, the inlet 62 at the end of the supply member 60 may include one or more openings for discharging the solids and one or more openings for discharging the combustion air. When the solids and conveying air are supplied separately, the solids and the combustion air do not merge during transport by the supply member 60.

In the example shown in Figures 2 and 3, one of the two supply members 60 is referred to as "supply member 60a" and the other as "supply member 60b." Supply member 60a and supply member 60b have similar functions and configurations. In the direction of gas flow inside the calciner 30, at least a portion of the inlet 62 of supply member 60a is positioned at the same position as at least a portion of the inlet 62 of supply member 60b. The direction of gas flow inside the calciner 30 (hereinafter referred to as "gas flow direction F") is defined as the direction from the inlet 30a, through which exhaust gas from the rotary kiln 40 of the calciner 30 is introduced, to the outlet 30b, through which combustion gas containing that exhaust gas is discharged.

2 and 3, the gas flow direction F is a vertical direction from bottom to top. Inside the calciner 30, combustion gas, including exhaust gas from the rotary kiln 40, may circulate while swirling. The gas flow direction F is defined by the relative positions of the exhaust gas inlet 30a and the combustion gas outlet 30b. The height position of at least a portion of the inlet 62 of the supply member 60a may coincide with the height position of at least a portion of the inlet 62 of the supply member 60b. In a plan view (viewed vertically from above), the inlet 62 of the supply member 60a and the inlet 62 of the supply member 60b are at different positions in the circumferential direction around the central axis of the calciner 30. In one example, the angle (the smaller angle of deviation) between the inlet 62 of supply member 60a and the inlet 62 of supply member 60b in the circumferential direction may be approximately 150° to 180°, approximately 160° to 180°, or approximately 170° to 180°. The position of the inlet 62 in the circumferential direction in a plan view is defined by the center of the inlet 62.

In a plan view, the direction in which the end portions of the supply members 60 (supply members 60a and 60b) that function as nozzles extend may be perpendicular to the side wall of the calciner 30. The direction in which the end portions of the supply members 60 extend may coincide with a direction perpendicular to the inlet 62. Alternatively, in a plan view, the direction in which the end portions of the supply members 60 extend may be inclined with respect to a direction perpendicular to the side wall of the calciner 30 (the radial direction of the circumference around the central axis of the calciner 30) so as to follow the swirling flow formed in the calciner 30. In one example, the angle at which the end portions are inclined with respect to a direction perpendicular to the side wall of the calciner 30 in a plan view may be approximately 10°, 20°, 30°, or 40°.

In a case where the supply member 60 supplies pulverized coal as solid content, an example of the components, calorific value, and particle size distribution of the pulverized coal supplied from one or more supply members 60 will be described. The proximate analysis values (mass %: air-dry basis) of the volatile matter, moisture, fixed carbon, and ash content of the pulverized coal may be in the following ranges.
(a) The proximate analysis value of the volatile content may be 25% by weight or more, 26% by weight or more, 27% by weight or more, or 28% by weight or more. The proximate analysis value of the volatile content may be 35% by weight or less, 34% by weight or less, 33% by weight or less, or 32% by weight or less. In one example, the proximate analysis value of the volatile content is 25 to 35% by weight, or 28 to 32% by weight.
(b) The proximate analysis value of the moisture content may be 2.0% by weight or more, 2.2% by weight or more, 2.4% by weight or more, or 2.6% by weight or more. The proximate analysis value of the moisture content may be 4.0% by weight or less, 3.8% by weight or less, 3.6% by weight or less, or 3.4% by weight or less. In one example, the proximate analysis value of the moisture content is 2.0 to 4.0% by weight, or 2.6 to 3.4% by weight.
(c) The proximate analysis of fixed carbon may be 40% by weight or more, 42% by weight or more, 44% by weight or more, or 46% by weight or more. The proximate analysis of fixed carbon may be 60% by weight or less, 58% by weight or less, 56% by weight or less, or 54% by weight or less. In one example, the proximate analysis of fixed carbon is 40-60% by weight, or 46-54% by weight.
(d) The proximate analysis value of the ash content may be 10% by weight or more, 11% by weight or more, 12% by weight or more, or 13% by weight or more. The proximate analysis value of the ash content may be 25% by weight or less, 24% by weight or less, 23% by weight or less, or 22% by weight or less. In one example, the proximate analysis value of the ash content is 10 to 25% by weight, or 13 to 22% by weight.

In one example, the proximate analysis values of the components of pulverized coal are 25-35% by mass for volatile matter, 2-4% by mass for moisture, 40-60% by mass for fixed carbon, and 10-25% by mass for ash. The proximate analysis values of the components of pulverized coal are analytical values measured using the test method described in JIS M8812 "Coals and cokes - Proximate analysis methods."

The chemical analysis values (mass %: air-dry basis) of C (carbon), H (hydrogen), O (oxygen), N (nitrogen), and S (sulfur) of the pulverized coal may be in the following ranges.
(a) The chemical analysis value of C may be 60% by weight or more, 61% by weight or more, 62% by weight or more, or 63% by weight or more. The chemical analysis value of C may be 75% by weight or less, 74% by weight or less, 73% by weight or less, or 72% by weight or less. In one example, the chemical analysis value of C is 60-75% by weight, or 63-72% by weight.
(b) The chemical analysis of H may be 3.0% by weight or more, 3.2% by weight or more, 3.4% by weight or more, or 3.6% by weight or more. The chemical analysis of H may be 5.0% by weight or less, 4.8% by weight or less, 4.6% by weight or less, or 4.4% by weight or less. In one example, the chemical analysis of H is 3-5% by weight, or 3.6-4.4% by weight.
(c) The chemical analysis of O may be 6.0% by weight or more, 6.2% by weight or more, 6.4% by weight or more, or 6.6% by weight or more. The chemical analysis of O may be 9.0% by weight or less, 8.8% by weight or less, 8.6% by weight or less, or 8.4% by weight or less. In one example, the chemical analysis of O is 6-9% by weight, or 6.6-8.4% by weight.
(d) The chemical analysis of N may be 1.0% by weight or more, 1.1% by weight or more, 1.2% by weight or more, or 1.3% by weight or more. The chemical analysis of N may be 3.0% by weight or less, 2.8% by weight or less, 2.6% by weight or less, or 2.4% by weight or less. In one example, the chemical analysis of N is 1-3% by weight, or 1.3-2.4% by weight.
(e) The chemical analysis of S may be 0.1% by weight or more, 0.2% by weight or more, 0.3% by weight or more, or 0.4% by weight or more. The chemical analysis of S may be 1.0% by weight or less, 0.9% by weight or less, 0.8% by weight or less, or 0.7% by weight or less. In one example, the chemical analysis of S is 0.1-1.0% by weight, or 0.4-0.7% by weight.

In one example, the chemical analysis values (air-dry basis) of the components of pulverized coal are as follows: C 60-75 mass%, H 3-5 mass%, O 6-9 mass%, N 1-3 mass%, and S 0.1-1.0 mass%. The chemical analysis values (air-dry basis) of the components of pulverized coal are analytical values measured using the test methods described in JIS M8813 "Coals and cokes -- Elemental analysis methods" and JIS M8810 "Coals and cokes -- General rules for sampling, analysis, and test methods."

The chemical analysis values (mass %: dry and ash-free basis) of C, H, O, N, and S of the pulverized coal may be in the following ranges.
(a) The chemical analysis value of C may be 75% by weight or more, 76% by weight or more, 77% by weight or more, or 78% by weight or more. The chemical analysis value of C may be 90% by weight or less, 89% by weight or less, 88% by weight or less, or 87% by weight or less. In one example, the chemical analysis value of C is 75 to 90% by weight, or 78 to 88% by weight.
(b) The chemical analysis of H may be 4.0% by weight or more, 4.2% by weight or more, 4.4% by weight or more, or 4.6% by weight or more. The chemical analysis of H may be 6.0% by weight or less, 5.8% by weight or less, 5.6% by weight or less, or 5.4% by weight or less. In one example, the chemical analysis of H is 4-6% by weight, or 4.6-5.4% by weight.
(c) The chemical analysis of O may be 8.0% by weight or more, 8.2% by weight or more, 8.4% by weight or more, or 8.6% by weight or more. The chemical analysis of O may be 11.0% by weight or less, 10.8% by weight or less, 10.6% by weight or less, or 10.4% by weight or less. In one example, the chemical analysis of O is 8-11% by weight, or 8.6-10.4% by weight.
(d) The chemical analysis of N may be 1.0% by weight or more, 1.1% by weight or more, 1.2% by weight or more, or 1.3% by weight or more. The chemical analysis of N may be 3.0% by weight or less, 2.9% by weight or less, 2.8% by weight or less, or 2.7% by weight or less. In one example, the chemical analysis of N is 1-3% by weight, or 1.3-2.7% by weight.
(e) The chemical analysis of S may be 0.1% by weight or more, 0.2% by weight or more, 0.3% by weight or more, or 0.4% by weight or more. The chemical analysis of S may be 1.0% by weight or less, 0.9% by weight or less, 0.8% by weight or less, or 0.7% by weight or less. In one example, the chemical analysis of S is 0.1-1.0% by weight, or 0.4-0.7% by weight.

In one example, the chemical analysis values (dry and ash-free basis) of the components of pulverized coal are as follows: C 75-90 mass%, H 4-6 mass%, O 8-11 mass%, N 1-3 mass%, and S 0.1-1.0 mass%. The chemical analysis values (air-dry basis) of the components of pulverized coal are analytical values measured using the test methods described in JIS M8813 "Coals and cokes -- Elemental analysis methods" and JIS M8810 "Coals and cokes -- General rules for sampling, analysis, and test methods."

The calorific value of the pulverized coal (more specifically, the lower heating value of the pulverized coal on arrival) may be 4500 kcal/kg or more, 4700 kcal/kg or more, 4900 kcal/kg or more, or 5100 kcal/kg or more. In this disclosure, the calorific value of the pulverized coal refers to the lower heating value (on arrival). The calorific value of the pulverized coal may be 6500 kcal/kg or less, 6300 kcal/kg or less, 6100 kcal/kg or less, or 5900 kcal/kg or less. In one example, the calorific value of the pulverized coal is 4500 to 6500 kcal/kg, or 5100 to 5900 kcal/kg. The calorific value of pulverized coal, i.e., the lower calorific value of pulverized coal (on arrival), is measured using the test method described in JIS M8814 "Coals and cokes - Method for measuring gross calorific value using a bomb calorimeter and method for calculating net calorific value."

The particle size distribution of the pulverized coal (mass proportion for each particle size division) may be in the following ranges: The mass proportion (mass %) for each particle size division means the proportion of the mass of particles of that particle size division to the total mass of the pulverized coal.
(a) The content of particles having a particle size of less than 8.00 μm may be 15% by mass or less, 13% by mass or less, 11% by mass or less, or 9% by mass or less. It is also possible that no particles having a particle size of less than 8.00 μm are contained.
(b) The content of particles having a particle size of 8.00 μm or more and less than 16.00 μm may be 5% by mass or more, 6% by mass or more, 7% by mass or more, or 8% by mass or more. The content of particles having a particle size of 8.00 μm or more and less than 16.00 μm may be 20% by mass or less, 19% by mass or less, 18% by mass or less, or 17% by mass or less. In one example, the content of particles having a particle size of 8.00 μm or more and less than 16.00 μm is 5 to 20% by mass, or 8 to 17% by mass.
(c) The content of particles having a particle size of 16.00 μm or more and less than 32.00 μm may be 20% by mass or more, 22% by mass or more, 24% by mass or more, or 26% by mass or more. The content of particles having a particle size of 16.00 μm or more and less than 32.00 μm may be 40% by mass or less, 38% by mass or less, 36% by mass or less, or 34% by mass or less. In one example, the content of particles having a particle size of 16.00 μm or more and less than 32.00 μm is 20 to 40% by mass, or 26 to 34% by mass.
(d) The content of particles having a particle size of 32.00 μm or more and less than 64.00 μm may be 20% by mass or more, 22% by mass or more, 24% by mass or more, or 26% by mass or more. The content of particles having a particle size of 32.00 μm or more and less than 64.00 μm may be 40% by mass or less, 38% by mass or less, 36% by mass or less, or 34% by mass or less. In one example, the content of particles having a particle size of 32.00 μm or more and less than 64.00 μm is 20 to 40% by mass, or 26 to 34% by mass.
(e) The content of particles having a particle size of 64.00 μm or more and less than 128.00 μm may be 10% by mass or more, 12% by mass or more, 14% by mass or more, or 16% by mass or more. The content of particles having a particle size of 64.00 μm or more and less than 128.00 μm may be 30% by mass or less, 28% by mass or less, 26% by mass or less, or 24% by mass or less. In one example, the content of particles having a particle size of 64.00 μm or more and less than 128.00 μm is 10 to 30% by mass, or 16 to 24% by mass.
(f) The content of particles having a particle size of 128.00 μm or more may be 10% by mass or less, 9% by mass or less, 8% by mass or less, or 7% by mass or less. It is not necessary for particles having a particle size of 128.00 μm or more to be contained.

In one example, the particle size distribution of the pulverized coal is such that particles having a particle size of 8.00 μm or more and less than 16.00 μm account for 5 to 20 mass %, particles having a particle size of 16.00 μm or more and less than 32.00 μm account for 20 to 40 mass %, particles having a particle size of 32.00 μm or more and less than 64.00 μm account for 20 to 40 mass %, and particles having a particle size of 64.00 μm or more and less than 128.00 μm account for 10 to 30 mass %. In this case, the pulverized coal may contain at least one of particles having a particle size of less than 8.00 μm and particles having a particle size of 128.00 μm or more, or may not contain both of these particles. The particle size distribution (particle size) of the pulverized coal is measured using the test method described in JIS Z8825, "Particle Size Analysis - Laser Diffraction and Scattering Method."

The thermal energy source supply unit 50 has one or more supply members 70 (second supply members). In the example shown in FIG. 2, two supply members 70 are provided. The supply members 70 are members (burners) that supply ammonia as a thermal energy source to the interior of the calciner 30. The supply members 70 are configured to supply an ammonia-containing gas containing ammonia. The ammonia-containing gas supplied by the supply member 70 may be ammonia gas alone, or may be a mixed gas of ammonia gas with other gases such as air or methane.

As shown in FIG. 3, the supply member 70 may supply ammonia along with combustion air to the interior of the calciner 30. The ammonia and combustion air may be combined in the supply member 70 before being introduced into the interior of the calciner 30, or the ammonia and combustion air may be supplied separately without being combined. The air ratio of the combustion air supplied together with ammonia is, for example, 0.1 to 1.0. The air ratio is defined as the ratio of the amount of air actually supplied to the minimum amount of air required for theoretically completely combusting the ammonia supplied from the supply member 70.

The air ratio of the combustion air from the supply member 70 may be 0.15 or more, 0.2 or more, or 0.25 or more, from the viewpoint of promoting the combustion of ammonia. The air ratio of the combustion air from the supply member 70 may be 0.9 or less, 0.8 or less, or 0.7 or less, from the viewpoint of efficiently introducing air. In one example, exhaust gas from the chlorine bypass equipment is introduced as combustion air from each of the supply members 70 and 60.

The supply member 70 may supply ammonia-containing gas continuously while the calciner 30 is operating, or may supply ammonia-containing gas only for a portion of the period while the calciner 30 is operating.

A part of the ammonia-containing gas supplied from the supply member 70 may be used as a thermal energy source, and another part may be used for denitration. That is, the reaction may occur not only as shown in the following formula (1) but also as shown in formula (2).
NH ₃ +1/4O ₂ → 1/2N ₂ +3/2H ₂ O (1)
_NH3 +NO+1/ _4O2 → _N2 + ₃ /2H2O (2)
The calciner 30 has a temperature range in which both the combustion reaction and the denitration reaction can proceed, and therefore can perform both the ammonia combustion reaction and the denitration reaction, thereby reducing the emissions of both carbon dioxide and nitrogen oxides.

The ammonia contained in the ammonia-containing gas supplied from the supply member 70 may be used for both combustion and denitration in the calciner 30, or all or most of the ammonia from the supply member 70 may be used in the combustion reaction, with the ammonia used for the denitration reaction supplied from an inlet 20 located separately from the supply member 70. The ammonia-containing gas supplied from the inlet 20 may contain only ammonia, or may be a mixture of ammonia gas and other gases. The inlet 20 is provided, for example, at the connection 38 that connects the outlet 30b of the calciner 30 to the cyclone C4 and through which exhaust gas from the calciner 30 flows.

An inlet 72 is provided at the end of the supply member 70, through which the ammonia-containing gas is discharged (blows) into the interior of the calciner 30. The end of the supply member 70 including the inlet functions as a nozzle. The inlet of the supply member 70 may be provided with one or more openings for introducing the ammonia-containing gas. The inlet 72 at the end of the supply member 70 may include one or more openings for discharging the combustion air in addition to one or more openings for discharging the ammonia-containing gas. A portion of the combustion air introduced together with the ammonia-containing gas may be discharged from the inlet 72 as a swirling flow, and another portion of the combustion air may be discharged from the inlet 72 without swirling (e.g., in a straight line). The end of the supply member 70 that functions as a nozzle may be installed horizontally. As shown in FIG. 3, the end of the supply member 70 may be connected to the side wall of the calciner 30.

2 and 3, one of the two supply members 70 is referred to as "supply member 70a" and the other as "supply member 70b." Supply member 70a and supply member 70b have similar functions and configurations. In the gas flow direction F within the calciner 30, at least a portion of the inlet 72 of supply member 70a is disposed at the same position as at least a portion of the inlet 72 of supply member 70b. When the gas flow direction F is along the vertical direction, the height position of at least a portion of the inlet 72 of supply member 70a may coincide with the height position of at least a portion of the inlet 72 of supply member 70b. In a plan view, the inlet 72 of supply member 70a and the inlet 72 of supply member 70b are positioned at different circumferential positions around the central axis of the calciner 30. In one example, the angle (the smaller angle of deviation) between the inlet 72 of supply member 70a and the inlet 72 of supply member 70b in the circumferential direction may be approximately 150° to 180°, approximately 160° to 180°, or approximately 170° to 180°. The position of the inlet 72 in the circumferential direction in a plan view is defined by the center of the inlet 72.

In a plan view, the direction in which the end portions of the supply members 70 (supply members 70a and 70b) that function as nozzles extend may be perpendicular to the side wall of the calciner 30. The direction in which the end portions of the supply members 70 extend may coincide with a direction perpendicular to the inlet 72. Alternatively, in a plan view, the direction in which the end portions of the supply members 70 extend may be inclined with respect to a direction perpendicular to the side wall of the calciner 30 (the radial direction of the circumference around the central axis of the calciner 30) so as to follow the swirling flow formed within the calciner 30. In one example, the angle at which the end portions are inclined with respect to a direction perpendicular to the side wall of the calciner 30 in a plan view may be approximately 10°, 20°, 30°, or 40°.

Next, the relative positional relationship between one or more supply members 70 and one or more supply members 60 will be described. Below, the relative positional relationship will be described focusing on one supply member 70 and one supply member 60, but the same relative positional relationship applies to all combinations of supply members 70 and supply members 60.

Supply member 70 is formed separately from supply member 60. In other words, supply member 70 is physically separate from supply member 60. Supply member 70 discharges ammonia gas from a position different from the position from which supply member 60 supplies the thermal energy source. In other words, the position from which supply member 60 supplies solids to the interior of calciner 30 and the position from which supply member 70 supplies ammonia-containing gas to the interior of calciner 30 are different from each other. In this disclosure, supplying (discharging) a thermal energy source from different positions (locations) means that two separately constructed supply members each supply (discharge) a thermal energy source.

Based on the gas flow direction F within the calciner 30, the position from which the supply member 70 supplies ammonia is located upstream of the position from which the supply member 60 supplies a thermal energy source containing solids. The position from which the supply member 70 supplies ammonia corresponds to the position of the inlet 72 of the supply member 70, which discharges ammonia (ammonia-containing gas), and this position will be referred to below as the "supply position of the supply member 70." The position from which the supply member 60 supplies a thermal energy source containing solids corresponds to the position of the inlet 62 of the supply member 60, which discharges the thermal energy source, and this position will be referred to below as the "supply position of the supply member 60." When the gas flow direction F is vertical, the uppermost position (highest position) of the inlet 72 of the supply member 70 is located below the lowermost position (lowest position) of the inlet 62 of the supply member 60.

As described above, the supply positions of one or more supply members 70 (all of them) are arranged upstream of the supply positions of one or more supply members 60 (all of them) in the gas flow direction F. When the gas flow direction F is vertical, the supply positions of one or more supply members 70 (all of them) are arranged lower than the supply positions of one or more supply members 60 (all of them). In the example shown in FIG. 2, the supply position of supply member 70a is arranged lower than both the supply position of supply member 60a and the supply position of supply member 60b. The supply position of supply member 70b is also arranged lower than both the supply position of supply member 60a and the supply position of supply member 60b. In a plan view, the supply positions of supply member 60a and supply member 70a may be approximately aligned, and the supply positions of supply member 60b and supply member 70b may be approximately aligned. The supply position of supply member 60a (supply member 60b) and the supply position of supply member 70a (supply member 70b) may be different from each other in a plan view, as long as this does not affect the combustion of ammonia or solid content. In one example, the supply positions may be offset from each other by approximately 10°, 20°, or 30° in the circumferential direction around the central axis of calciner 30 in a plan view.

There is a concern that the supply of ammonia into the calciner 30 will increase the concentration of carbon monoxide contained in the gas discharged from the calciner 30. The following two factors are thought to be factors that cause the increase in carbon monoxide concentration.
(A) Inhibition of combustion of solids such as pulverized coal by the combustion of ammonia (B) Reaction of ammonia with carbon dioxide

Regarding factor (A), it is believed that oxygen around the solids is consumed first by the combustion of ammonia gas, a combustible gas, resulting in a temporary shortage of oxygen for the combustion reaction of the solids. Generally, the combustion of solids involves thermal decomposition of the solids into gas and char, which then combust separately. Therefore, it is presumed that the combustion rate of the combustible gas (ammonia gas) is faster than that of the solids. Consider the case where solids, which have a relatively slow combustion rate, and ammonia gas, which has a relatively fast combustion rate, are supplied from the same position in the gas flow direction F within the calciner 30, or the case where solids are supplied upstream and ammonia gas is supplied downstream. In these cases, due to the difference in combustion rate, oxygen is consumed around the downstream supply position due to the combustion of ammonia gas, resulting in a temporary shortage of oxygen at the upstream supply position for burning the incompletely combusted solids. This results in accelerated carbon monoxide generation.

In contrast, in the manufacturing apparatus 100, ammonia gas is supplied upstream in the gas flow direction F by the supply member 70, and solid content is supplied downstream by the supply member 60. In this case, the possibility of oxygen shortages occurring around the solid content supplied downstream due to the combustion of ammonia gas can be reduced. It is also believed that the reaction between carbon dioxide generated by the combustion of the solid content and ammonia can be suppressed. Therefore, by supplying ammonia gas upstream and the solid content downstream, it is possible to suppress an increase in carbon monoxide concentration caused by ammonia gas.

The thermal energy source supply unit 50 supplies various thermal energy sources to the inside of the calciner 30 so that the calorific value ratio, defined below, is 0.01 to 0.90.
Calorific value ratio: The ratio of the calorific value of the ammonia supplied from one or more supply members 70 to the total calorific value of the thermal energy sources supplied from one or more supply members 60 and one or more supply members 70.
The total calorific value is the sum of the calorific values of all the thermal energy sources supplied from one or more supply members 60 and all the calorific values of all the thermal energy sources supplied from one or more supply members 70. The calorific value of ammonia supplied from one or more supply members 70 is the calorific value of all the ammonia supplied from one or more supply members 70. In this disclosure, the calorific value of ammonia refers to the lower heating value (anhydrous basis). The calorific value of ammonia may be 3000 kcal/kg or more, 3200 kcal/kg or more, 3400 kcal/kg or more, or 3600 kcal/kg or more. The calorific value of ammonia may be 6000 kcal/kg or less, 5800 kcal/kg or less, 5600 kcal/kg or less, or 5400 kcal/kg or less. In one example, the calorific value of ammonia is 3000 to 6000 kcal/kg, or 3600 to 5400 kcal/kg.

From the viewpoint of promoting the effective use of ammonia, the calorific value ratio may be 0.05 or more, 0.1 or more, 0.15 or more, or 0.20 or more. From the viewpoint of suppressing inhibition of combustion of solids due to ammonia, the calorific value ratio may be 0.7 or less, 0.55 or less, 0.50 or less, 0.45 or less, 0.4 or less, 0.35 or less, or 0.3 or less. The calorific value ratio may be 0.01 to 0.55. In this case, the ratio of the calorific value of the thermal energy source containing solids supplied from one or more supply members 60 to the total calorific value may be 0.45 to 0.99. The calorific value ratio may be 0.01 to 0.3. In this case, the ratio of the calorific value of the thermal energy source containing solids supplied from one or more supply members 60 to the total calorific value may be 0.7 to 0.99. These calorific value ratios can be calculated using the supply amounts of various thermal energy sources.

The manufacturing apparatus 100 may include one or more supply members 80 (third supply members). In the example shown in FIG. 2, one supply member 80 is provided, but two or more supply members 80 may be provided. The supply member 80 is a member that supplies hot gas containing oxygen and having a temperature of 700°C to 1000°C to the interior of the calciner 30. The temperature of the hot gas supplied from the supply member 80 may be 800°C to 900°C. The supply member 80 may supply the extracted gas from the clinker cooler 48 to the interior of the calciner 30 as the hot gas.

An inlet is provided at the end of the supply member 80 for discharging (blowing) hot gas into the interior of the calciner 30. The position at which hot gas is supplied by the supply member 80 corresponds to the position of the inlet provided at the end of the supply member 80, and hereinafter this position is referred to as the "supply position of the supply member 80." In the gas flow direction F within the calciner 30, the supply positions of one or more supply members 80 may correspond to the supply positions of one or more supply members 60, or may be located upstream of the supply positions and downstream of the supply positions of one or more supply members 70. The phrase "the supply position of a supply member 80 corresponds to the supply position of a supply member 60 in the gas flow direction F within the calciner 30" means that at least a portion of the inlet of the supply member 80 and at least a portion of the inlet 62 of the supply member 60 are in the same position. Blowing hot gas from the supply member 80 into the interior of the calciner 30 can further improve the combustibility of solids.

In the example shown in FIG. 2, the supply position of supply member 80 is located lower than the supply positions of both supply member 60a and supply member 60b. That is, the uppermost position of the inlet of supply member 80 is located lower than the lowermost position of the inlet of both supply member 60a and supply member 60b. Furthermore, the supply position of supply member 80 is located higher than the supply positions of both supply member 70a and supply member 70b. That is, the lowermost position of the inlet of supply member 80 is located higher than the uppermost position of the inlet of both supply member 70a and supply member 70b. The supply position of supply member 80 may be located between the supply positions of supply member 60 and supply member 70, closer to the supply position of supply member 60. Unlike the example shown in FIG. 2, the height position of the supply position of supply member 80 may coincide with the height position of the supply position of supply member 60a and the height position of the supply position of supply member 60b. The fact that the height positions of the supply positions are the same means that the height position of at least a portion of the inlet of one supply member is the same as the height position of at least a portion of the inlet of another supply member. If another supply member 80 is provided in addition to one supply member 80, the positional relationship of the other supply member 80 to supply members 60 and 70 also applies in the same way.

When one supply member 60 and one supply member 80 are provided, in a plan view, the supply position of the supply member 80 may be approximately aligned with the position of the downstream supply member 60 in the circumferential direction around the central axis of the calciner 30, or the angle of deviation from each other may be approximately 30° or less. In this case, it is possible to more effectively increase the combustion temperature around the solid content. Even when two supply members 60 and two supply members 80 are provided, the degree of circumferential deviation between the supply position of the supply member 60 and the supply position of the corresponding supply member 80 may be approximately aligned or may be approximately 30° or less.

[Method of manufacturing cement clinker]
Next, as an example of a method for producing cement clinker, a clinker production process executed in the production apparatus 100 will be described. The clinker production process executed in the production apparatus 100 includes, for example, a preheating process, a calcining process, a firing process, and a cooling process. These processes are executed in at least partially overlapping periods. The preheating process is a process in which cement raw materials are preheated in cyclones C1 to C4 by high-temperature gases including exhaust gas from the rotary kiln 40.

The calcination process is a process in which the cement raw materials are calcined in the calciner 30 using exhaust gas from the rotary kiln 40 and various thermal energy sources supplied to the interior of the calciner 30. The firing process is a process in which the cement raw materials are calcined in the rotary kiln 40 using combustion gas from the burner 44. The cooling process is a process in which the clinker produced in the rotary kiln 40 is cooled in the clinker cooler 48.

An example of the calcination process will be described in detail. The calcination process includes, for example, a first supply process, a second supply process, a third supply process, and a heating process. The first supply process, second supply process, third supply process, and heating process are each performed during at least partially overlapping periods. The first supply process is a process in which a thermal energy source containing solids is supplied to the interior of the calciner 30 by one or more supply members 60. In the first supply process, for example, a thermal energy source containing solids is supplied from each of supply members 60a and 60b (two supply members 60). The solids supplied from each supply member 60 in the first supply process may be pulverized coal, waste, or both pulverized coal and waste.

The second supply step is a step of supplying ammonia to the interior of the calciner 30 using one or more supply members 70. In the second supply step, for example, ammonia-containing gas is supplied from each of two supply members 70, supply member 70a and supply member 70b (two supply members 70). In the second supply step, ammonia may be supplied to the interior of the calciner 30 together with air having an air ratio of 0.1 to 1.0. The position from which each supply member 70 supplies ammonia in the second supply step is located upstream, relative to the gas flow direction F, of the position from which each supply member 60 supplies a thermal energy source containing solids in the first supply step.

The ratio of the calorific value of the ammonia supplied to the calciner 30 in the second supply step to the total calorific value of the thermal energy sources supplied to the calciner 30 in the first supply step and the second supply step is 0.01 to 0.90. The above ratio related to the calorific value of the ammonia may be 0.01 to 0.55. In this case, the ratio of the calorific value of the thermal energy source including solids supplied to the calciner 30 in the first supply step to the total calorific value of the thermal energy sources supplied to the calciner 30 in the first supply step and the second supply step may be 0.45 to 0.99.

The third supply step is a step of supplying hot gas containing oxygen to the interior of the calciner 30 using one or more supply members 80 (e.g., one or two supply members 80). The temperature of the hot gas supplied from the supply members 80 may be 900°C to 1200°C. The hot gas supplied from the supply members 80 may be the extracted gas used to cool the clinker in the clinker cooler 48. The position at which the supply members 80 supply the hot gas in the third supply step may be the same as or upstream of the position at which each supply member 60 supplies the thermal energy source containing solids in the first supply step, based on the gas flow direction F. The position at which the supply members 80 supply the hot gas in the third supply step may be downstream, based on the gas flow direction F, of the position at which each supply member 70 supplies ammonia in the second supply step.

The heating process is a process in which the cement raw materials are heated in the calciner 30 while burning ammonia gas. The calcination process may also include a denitration process. For example, in the denitration process, an ammonia-containing gas is supplied into the connection part 38 from an inlet 20 provided in the connection part 38, which connects the upper part (outlet 30b) of the calciner 30 to the cyclone C4. This allows the exhaust gas used for calcination in the calciner 30 to be denitrified.

[Verification results by simulation]
Next, the results of a simulation performed to verify the effect of supplying ammonia to the interior of the calciner 30 will be described. The simulation was performed using R-FLOW, a thermal fluid and powder analysis software manufactured by R-FLOW Corporation. In the simulated conditions for the calciner 30, two burners were arranged in the lower stage and two burners were arranged in the upper stage. Hereinafter, the two burners arranged in the lower stage will be referred to as "lower stage burner 1" and "lower stage burner 2," and the two burners arranged in the upper stage will be referred to as "upper stage burner 1" and "upper stage burner 2." The lower stage burner 1 and the lower stage burner 2 correspond to the supply member 70a and the supply member 70b, respectively, and the upper stage burner 1 and the upper stage burner 2 correspond to the supply member 60a and the supply member 60b, respectively. It was assumed that only pulverized coal was supplied as the solid content, without including any waste. It is assumed that 100% pure ammonia is supplied, and the lower heating value of ammonia (anhydrous basis, 100% purity) is 4,427 kcal/kg, or 1.86×10 ⁷ J/kg.

The proximate analysis values (mass %: air-dry basis), chemical analysis values (mass %: air-dry basis), and chemical analysis values (mass %: dry ash-free basis) of the components of the pulverized coal assumed in the simulation are shown in Table 1. The lower heating value (arrival basis) of the pulverized coal was set to 5,749 kcal/kg, i.e., 2.415 × 10 ⁷ J/kg.

The particle size distribution of the pulverized coal assumed in the simulation is shown in Table 2 below.

In Table 2 above, the cumulative mass ratio (11.00 mass%) for a particle size of 8.00 μm means the ratio of the mass of particles less than 8.00 μm to the total mass of pulverized coal. The mass ratio (6.00 mass%) for a particle size of 8.00 μm means the ratio of the mass of particles with a particle size of 4.00 μm or more and less than 8.00 μm to the total mass of pulverized coal. The same applies to columns for particle sizes other than 8.00 μm.

(Reference example)
A simulation was carried out in which pulverized coal was supplied from all four burners. The simulation conditions are outlined below.
Upper burners 1 and 2: The calorific value ratio of the pulverized coal supplied from each burner was 25%, and the supply amount was 1.3 t/h.
Lower burners 1 and 2: The calorific value ratio of the pulverized coal supplied from each burner was 25%, and the supply amount was 1.3 t/h.
In each burner, pulverized coal is transported by carrier air, and the flow rate of the carrier air is set to 500 ^Nm3 /h and the oxygen concentration is set to 21%. In other words, the amount of oxygen resulting from the carrier air from each burner is 500 x 0.21 = 105 ^Nm3 /h.
- Each burner is supplied with combustion air separately from (pulverized coal + carrier air), with a flow rate of 1,200 ^Nm3 /h and an oxygen concentration of 18%. In other words, the amount of oxygen resulting from the combustion air from each burner is 1,200 x 0.18 = 216 ^Nm3 /h.
The flow rate of the ascending flow introduced from the inlet 30a of the calciner 30 was 40,000 ^Nm3 /h, and the oxygen concentration of the ascending flow was 4%. In other words, when focusing on one of the lower stage burners 1 and 2, oxygen in the vicinity of that burner (for example, lower stage burner 1) is added at 40,000/2 x 0.04 = 800 ^Nm3 /h from half (one side) of the ascending flow in the calciner 30, in addition to the oxygen in the transport air and combustion air.
The theoretical amount of oxygen required for combustion of 1.3 t/h of pulverized coal, which corresponds to a calorific value ratio of 25%, is 1,830 Nm ³ /h. In contrast, the amount of oxygen near the lower burner 1 is 105 + 216 + 800 = 1,121 Nm ³ /h. In other words, the amount of oxygen required for combustion of pulverized coal near the lower burner 1 is less than the theoretical amount of oxygen required for combustion, and the air ratio is 1,121/1,830 = 0.61.

The heat rate ratio for each burner refers to the ratio of the heat rate of the thermal energy supplied from that burner to the total heat rate of the thermal energy sources supplied from upper burners 1 and 2 and lower burners 1 and 2. Oxygen concentration refers to the concentration on a volume basis (volume %).

FIG. 4 shows the concentration source distribution of carbon dioxide (CO ₂ ) generated inside the calciner 30, obtained by a simulation according to a reference example. The contour diagram shown in FIG. 4 is the simulation result of the CO ₂ concentration source distribution inside the calciner 30. The color intensity in the contour diagram represents the amount of CO ₂ generated and lost per unit time and unit volume. The lower end of the contour diagram corresponds to the inlet 30 a of the calciner 30, and the upper end of the contour diagram corresponds to the outlet 30 b (outlet) of the calciner 30. From the results shown in FIG. 4, it can be seen that the combustion rate of pulverized coal is slow, and CO ₂ generation continues up to near the outlet of the calciner 30.

Example 1
Similar to the introduction of the thermal energy source described with reference to Fig. 2 etc., a simulation was performed in which pulverized coal was supplied from the upper stage burners 1 and 2 and ammonia was supplied from the lower stage burners 1 and 2. The conditions for the simulation are outlined below. The conditions for the upward flow in the calciner 30 were the same as those in the reference example.
Upper burners 1 and 2: The supply rate of pulverized coal supplied from each burner was set to 2 t/h.
In each of the upper stage burners 1 and 2, pulverized coal is transported by transport air, the flow rate of the transport air is set to 500 Nm ³ /h, and the oxygen concentration is set to 21%.
In each of the upper stage burners 1 and 2, combustion air is supplied in addition to (pulverized coal + transport air), and the flow rate of the combustion air is set to 1,200 Nm ³ /h and the oxygen concentration is set to 18%.
Lower burners 1 and 2: The amount of ammonia supplied from each burner was set to 1,100 Nm ³ /h.
In each of the lower stage burners 1 and 2, combustion air was supplied separately from ammonia, the flow rate of the combustion air was set to 1,200 Nm ³ /h, and the oxygen concentration was set to 18%.
Each of the lower burners 1 and 2 was supplied with combustion air other than the above (ammonia + combustion air), and the flow rate of the combustion air was set to 500 Nm ³ /h and the oxygen concentration was set to 21%.

Under the above conditions for Example 1, the calorific value ratio of the pulverized coal from each of the upper stage burners 1 and 2 is 38%, and the calorific value ratio of the ammonia from each of the lower stage burners 1 and 2 is 12%. In other words, the ratio of the calorific value of the ammonia supplied from the lower stage burners 1 and 2 to the total calorific value of the thermal energy sources supplied from all four burners (corresponding to the calorific value ratio described above) is 0.24.

Fig. 5 shows the concentration source distribution of carbon dioxide (CO ₂ ) generated inside the calciner 30, obtained by the simulation according to Example 1. The simulation results shown in Fig. 5 correspond to the simulation results shown in Fig. 4. In the simulation according to Example 1 as well, it can be seen that the combustion rate of pulverized coal is slow, and CO ₂ generation continues up to near the outlet of the calciner 30.

FIG. 6 shows the concentration source distribution of ammonia (NH ₃ ) generated inside the calciner 30, obtained by the simulation of Example 1. The contour diagram shown in FIG. 6 is the simulation result of the concentration source distribution of NH ₃ inside the calciner 30. The color intensity in the contour diagram represents the amount of NH ₃ generated and lost per unit time and unit volume. The lower end of the contour diagram corresponds to the inlet 30a of the calciner 30, and the upper end of the contour diagram corresponds to the outlet 30b of the calciner 30. It can be seen from the results shown in FIG. 6 that the combustion rate of ammonia is fast and that ammonia disappears immediately after being supplied from the lower burner.

Under the above conditions for Example 1, the theoretical combustion oxygen for 1100 Nm ³ /h of ammonia is 1100 × 3/4 = 825 Nm ³ /h according to the above formula (1). The amount of oxygen near the lower burner 1 is 1200 × 0.18 + 500 × 0.21 = 321 Nm ³ /h from the supply amount of combustion air and the oxygen concentration. The air ratio of the combustion air from the lower burner 1 is 321/825 (approximately 0.39). In addition to the oxygen from the combustion air, 40000/2 × 0.04 = 800 Nm ³ /h of oxygen is added to the oxygen near the lower burner 1 from half (one side) of the upward flow in the calciner 30, for a total of 1121 Nm ³ /h, which exceeds the theoretical combustion oxygen. Due to the oxygen exceeding the theoretical combustion oxygen, the ammonia from the lower stage burner 1 is theoretically completely combusted. There is no ammonia near the upper stage burner 1 that preferentially consumes oxygen.

Example 2
As in Example 1, a simulation was performed in which pulverized coal was supplied from the upper stage burners 1 and 2 and ammonia was supplied from the lower stage burners 1 and 2. The conditions for the simulation are outlined below. The conditions for the upward flow in the calciner 30 were the same as those in the reference example.
Upper burners 1 and 2: The supply rate of pulverized coal supplied from each burner was set to 1.3 t/h.
In each of the upper stage burners 1 and 2, pulverized coal is transported by transport air, the flow rate of the transport air is set to 500 Nm ³ /h, and the oxygen concentration is set to 21%.
In each of the upper stage burners 1 and 2, combustion air is supplied separately from (pulverized coal + conveying air), and the flow rate of the combustion air is set to 1,200 Nm ³ /h and the oxygen concentration is set to 18%.
Lower burners 1 and 2: The amount of ammonia supplied from each burner was set to 2,300 Nm ³ /h.
In each of the lower stage burners 1 and 2, combustion air was supplied separately from ammonia, the flow rate of the combustion air was set to 1,200 Nm ³ /h, and the oxygen concentration was set to 18%.
Each of the lower burners 1 and 2 was supplied with combustion air other than the above (ammonia + combustion air), and the flow rate of the combustion air was set to 500 Nm ³ /h and the oxygen concentration was set to 21%.

Under the above conditions for Example 2, the calorific value ratio of the pulverized coal from each of the upper stage burners 1 and 2 is 25%, and the calorific value ratio of the ammonia from each of the lower stage burners 1 and 2 is 25%. In other words, the ratio of the calorific value of the ammonia supplied from the lower stage burners 1 and 2 to the total calorific value of the thermal energy sources supplied from all four burners (corresponding to the calorific value ratio described above) is 0.50.

Fig. 7 shows the concentration source distribution of carbon dioxide (CO ₂ ) generated inside the calciner 30, obtained by the simulation according to Example 2. The simulation results shown in Fig. 7 correspond to the simulation results shown in Fig. 4. In the simulation according to Example 2 as well, it can be seen that the combustion rate of pulverized coal is slow, and CO ₂ generation continues up to near the outlet of the calciner 30.

Fig. 8 shows the concentration source distribution of ammonia (NH ₃ ) generated inside the calciner 30, obtained by the simulation according to Example 2. The simulation results shown in Fig. 8 correspond to the simulation results shown in Fig. 6. The results shown in Fig. 8 show that the combustion rate of ammonia is fast, and most of the ammonia disappears immediately after being supplied from the lower stage burner.

Under the above conditions for Example 2, the theoretical combustion oxygen for 2,300 Nm ³ /h of ammonia is 2300 × 3/4 = 1725 Nm ³ /h according to the above formula (1). The amount of oxygen near the lower burner 1 is 1200 × 0.18 + 500 × 0.21 = 321 Nm ³ /h based on the combustion air supply rate and oxygen concentration. In addition to the oxygen from the combustion air, oxygen of 40,000/2 × 0.04 = 800 Nm ³ /h is added near the lower burner 1 from half (one side) of the ascending flow in the calciner 30, for a total of 1121 Nm ³ /h, and the air ratio is 1121/1725 = 0.65. The unburned ammonia that is generated diffuses upward and is completely combusted by cooler bleed gas (e.g., oxygen concentration of 20% or more) introduced from downstream of the gas flow. Ammonia, which preferentially consumes oxygen, is not present near the upper stage burner 1 to which pulverized coal is supplied.

(Comparative Example 1)
A simulation was performed in which pulverized coal and ammonia were supplied from the upper stage burner 1 and the lower stage burner 1, and pulverized coal was supplied from the upper stage burner 2 and the lower stage burner 2. The conditions for the simulation are outlined below. The conditions for the upward flow in the calciner 30 were the same as those in the reference example.
Upper burner 1 and lower burner 1: The supply rate of pulverized coal supplied from each burner was 1 t/h, and the supply rate of ammonia was 1,100 Nm ³ /h.
Upper burner 2 and lower burner 2: The supply rate of pulverized coal supplied from each burner was set to 1 t/h.
Pulverized coal is transported by transport air in each of the four burners, and the flow rate of the transport air is set to 500 Nm ³ /h and the oxygen concentration is set to 21%.
At each of the upper burner 1 and the lower burner 1, combustion air is supplied in addition to (pulverized coal + transport air) and ammonia, and the flow rate of the combustion air is set to 1,200 Nm ³ /h and the oxygen concentration is set to 18%.
In each of the upper stage burners 2 and the lower stage burners 2, combustion air is supplied in addition to (pulverized coal + transport air), and the flow rate of the combustion air is set to 1,200 Nm ³ /h and the oxygen concentration is set to 18%.

Under the above conditions for Comparative Example 1, the calorific value ratio of pulverized coal from each of the four burners was 19%, and the calorific value ratio of ammonia from each of the upper stage burner 1 and the lower stage burner 1 was 12%. FIG. 9 shows the concentration source distribution of carbon dioxide (CO ₂ ) generated inside the calciner 30 obtained by the simulation for Comparative Example 1. The simulation results shown in FIG. 9 correspond to the simulation results shown in FIG. 4. FIG. 10 shows the concentration source distribution of ammonia (NH ₃ ) generated inside the calciner 30 obtained by the simulation for Comparative Example 1. The simulation results shown in FIG. 10 correspond to the simulation results shown in FIG. 6. The results shown in FIGS. 9 and 10 also show that the combustion rate of pulverized coal is slow, CO ₂ generation continues up to the vicinity of the outlet of the calciner 30, and that the combustion rate of ammonia is fast.

Under the above conditions for Comparative Example 1, the theoretical combustion oxygen amount of pulverized coal from the lower burner 1 was calculated as follows. Based on the elemental composition of pulverized coal, namely C 66.5 wt% (air-dry basis), H 4.0 wt% (air-dry basis), and O 7.3 wt% (air-dry basis), and taking into account the reaction equations C + O ₂ = CO ₂ and H + (1/4) O ₂ = (1/2) H ₂ O, the theoretical combustion oxygen amount per kg of pulverized coal is {66.5/100/12 + (4 - 7.3/8)/100/1 × (1/4)} × 22.414 = 1.41 Nm ³ /kg. Converting this to a per ton (ton), the theoretical combustion oxygen amount is 1,410 Nm ³ /t. The theoretical amount of oxygen required for combustion of 1100 Nm ³ /h of ammonia and 1 t/h of pulverized coal is 825 + 1410 = 2235 Nm ³ /h. In contrast, the amount of oxygen available near the lower burner 1 is 500 × 0.21 + 1200 × 0.18 = 321 Nm ³ /h, based on the supply amounts of carrier air and combustion air and the oxygen concentration. Adding to this is the oxygen (800 Nm ³ /h) contained in one side of the ascending flow in the calciner 30, for a total amount of oxygen of 321 + 800 = 1121 Nm ³ /h. Near the lower burner 1, the amount of oxygen available for combustion of ammonia and pulverized coal is less than the theoretical amount of oxygen required for combustion, and ammonia, which has a faster combustion rate, preferentially consumes oxygen and burns completely, but there is a shortage of oxygen for the pulverized coal, resulting in unburned fuel. Similarly, in the vicinity of the upper burner 1, ammonia is completely burned, but unburned pulverized coal is generated.

(Comparative Example 2)
A simulation was performed in which pulverized coal was supplied from the upper stage burners 1 and 2, and pulverized coal and ammonia were supplied from the lower stage burners 1 and 2. The conditions for the simulation are outlined below. The conditions for the upward flow in the calciner 30 were the same as those in the reference example.
Upper stage burner 1 and upper stage burner 2: The supply rate of pulverized coal supplied from each burner was set to 1 t/h.
Lower stage burner 1 and lower stage burner 2: The supply rate of pulverized coal supplied from each burner was 1 t/h, and the supply rate of ammonia was 1,100 Nm ³ /h.
Pulverized coal is transported by transport air in each of the four burners, and the flow rate of the transport air is set to 500 Nm ³ /h and the oxygen concentration is set to 21%.
At each of the upper stage burners 1 and 2, combustion air is supplied in addition to (pulverized coal + transport air), and the flow rate of the combustion air is set to 1,200 Nm ³ /h and the oxygen concentration is set to 18%.
- In each of the lower stage burners 1 and 2, combustion air is supplied in addition to (pulverized coal + transport air) and ammonia, and the flow rate of the combustion air is set to 1,200 Nm ³ /h and the oxygen concentration is set to 18%.

Under the above conditions for Comparative Example 2, the calorific value proportion of pulverized coal from each of the four burners was 19%, and the calorific value proportion of ammonia from each of lower stage burners 1 and 2 was 12%. FIG. 11 shows the concentration source distribution of carbon dioxide (CO ₂ ) generated inside the calciner 30 obtained by simulation for Comparative Example 2. The simulation results shown in FIG. 11 correspond to the simulation results shown in FIG. 4. FIG. 12 shows the concentration source distribution of ammonia (NH ₃ ) generated inside the calciner 30 obtained by simulation for Comparative Example 2. The simulation results shown in FIG. 12 correspond to the simulation results shown in FIG. 6. The results shown in FIGS. 11 and 12 also show that the combustion rate of pulverized coal is slow, CO ₂ generation continues up to the vicinity of the outlet of the calciner 30, and that the combustion rate of ammonia is fast.

From the above conditions for Comparative Example 2, as in the calculation for Comparative Example 1, the theoretical amount of oxygen for combustion of 1100 Nm ³ /h of ammonia from the lower burner 1 and 1 t/h of pulverized coal is 2235 Nm ³ /h. In contrast, the amount of oxygen near the lower burner 1 is 321 + 800 = 1121 Nm ³ /h. Near the lower burner 1, the amount of oxygen is below the theoretical amount of oxygen for combustion of ammonia and pulverized coal, and ammonia, which has a faster combustion rate, preferentially consumes oxygen and burns completely, but there is a shortage of oxygen for the pulverized coal, resulting in unburned fuel. Near the upper burner 1, as in Examples 1 and 2, there is no ammonia that preferentially consumes oxygen.

(Summary of main conditions)
The main conditions in the above-mentioned Reference Example, Comparative Example 1, Comparative Example 2, and Examples 1 and 2 are shown in Table 3 below. In Table 3, the values in parentheses indicate the ratio of the heat amount of each thermal energy source to the total heat amount of the thermal energy sources from the four burners.

(Comparative verification based on the theoretical amount of oxygen for combustion)
Examples 1 and 2 are compared with Comparative Examples 1 and 2 with respect to phenomena occurring near the upper burner 1 and the lower burner 1. In Example 1, ammonia is completely combusted near the lower burner 1, and pulverized coal is not supplied, so the CO concentration can be lowered compared to Comparative Examples 1 and 2. Furthermore, near the upper burner 1, pulverized coal, which has a slow combustion rate, remains unburned due to a lack of oxygen. However, since ammonia, which preferentially consumes oxygen, is not present, the pulverized coal is more easily combusted than in Comparative Example 1. In Example 2, the CO concentration can also be lowered compared to Comparative Examples 1 and 2 near the lower burner 1, and since ammonia, which preferentially consumes oxygen, is not present near the upper burner 1, the pulverized coal is more easily combusted than in Comparative Example 1. In Comparative Example 1, the amount of unburned pulverized coal is greater near the upper burner 1 and the lower burner 1 due to the introduction of ammonia than in Examples 1 and 2, and in Comparative Example 2, the amount of unburned pulverized coal is greater near the lower burner 1 due to the introduction of ammonia.

As described above, the amount of unburned pulverized coal generated in Examples 1 and 2 is the smallest compared to Comparative Examples 1 and 2. Furthermore, by introducing cooler bleed gas (e.g., with an oxygen concentration of 20% or more) as hot gas into the calciner 30, the amount of unburned pulverized coal at the outlet of the calciner 30 can be reduced.

(Comparative verification of average CO concentrations across the cross section)
For each of the above-described Reference Example, Example 1, Example 2, Comparative Example 1, and Comparative Example 2, a simulation was performed to calculate the average CO concentration in a cross section at each height (by changing the height). The results calculated by the simulation are shown in Fig. 13. In the graph of Fig. 13, the horizontal axis represents the value obtained by dividing the height [m] from the bottom (furnace bottom) of the calciner 30 by the total length [m] in the vertical direction of the calciner 30, and the vertical axis represents the calculated value of the average CO concentration in a cross section perpendicular to the vertical direction.

From the graph shown in FIG. 13, the calculated values at a height near the lower burners 1 and 2 (the value on the horizontal axis is around 0.23) and the calculated values at a height near the outlet of the calciner 30 (the value on the horizontal axis is around 1.0) were read, and the results are shown in Table 4 below.

The results shown in Table 4 show that the average CO concentration in Examples 1 and 2 is lower than in Comparative Examples 1 and 2, both at heights near the lower burners and at heights near the outlet of the calciner 30. In other words, compared to Comparative Examples 1 and 2, in Examples 1 and 2, ammonia is burned while suppressing the occurrence of incomplete combustion of pulverized coal. The reason the average CO concentration is higher in Comparative Example 2 than in Comparative Example 1 at heights near the lower burners is that ammonia, which inhibits the combustion of pulverized coal, is supplied from the lower burners in greater amounts in Comparative Example 2 than in Comparative Example 1.

(Comparative verification of average _NH3 concentration at cross section)
For each of the above-described Reference Example, Example 1, Example 2, Comparative Example 1, and Comparative Example 2, the average NH ₃ concentration in a cross section was calculated for each height (by changing the height) by simulation. The results calculated by simulation are shown in Fig. 14. In the graph of Fig. 14, the horizontal axis represents the value obtained by dividing the height [m] from the bottom (furnace bottom) of the calciner 30 by the total length [m] in the vertical direction of the calciner 30, and the vertical axis represents the calculated value of the average NH ₃ concentration in a cross section perpendicular to the vertical direction.

The results of reading the calculated values from the graph shown in Figure 14 at a height near lower burners 1 and 2 (the horizontal axis value is around 0.23) and at a height near the middle of the calciner 30 (the horizontal axis value is around 0.32) are shown in Table 5 below.

The results shown in Table 5 reveal that the average NH3 concentration in Example 1 was lower than in Comparative Examples 1 and 2 at both the height near the lower burner (Z = 0.23) and the height near the middle of the calciner 30 (Z = 0.32). That is, it can be seen that ammonia was combusted better in Example 1 than in Comparative Examples 1 and 2. The average _NH3 concentration in Example ₂ near the lower burner and the middle of the calciner was higher than in Comparative Examples 1 and 2. This is because 2.1 times the amount of ammonia was added compared to Comparative Examples 1 and 2. However, as shown in FIG. 14 , ammonia was zero at the outlet of the calciner 30, indicating complete combustion and no problem. Furthermore, despite adding 2.1 times the amount of ammonia as in Comparative Examples 1 and 2, the CO concentration in Table 4 was lower than in Comparative Examples 1 and 2. This also demonstrates that it is effective to supply ammonia gas upstream of the pulverized coal, based on the gas flow inside the calciner 30.

Summary of the Disclosure
The method for producing cement clinker described above includes a first supply step of supplying a thermal energy source containing solids by one or more first supply members (60) to the interior (S) of a calciner (30) into which exhaust gas is introduced from a rotary kiln (40) that heats cement raw materials to produce cement clinker, and a second supply step of supplying ammonia by one or more second supply members (70) to the interior (S) of the calciner (30). With reference to the gas flow in the interior (S) of the calciner (30), the position at which the one or more second supply members (70) supply ammonia is located upstream of the position at which the one or more first supply members (60) supply the thermal energy source containing solids. The ratio of the calorific value of the ammonia supplied to the calciner (30) from the one or more second supply members (70) to the total calorific value of the thermal energy source supplied to the calciner (30) from the one or more first supply members (60) and the one or more second supply members (70) is 0.01 to 0.90.

As mentioned above, the occurrence of combustion inhibition of the solid content can lead to incomplete combustion of the solid content and increased generation of carbon monoxide (CO). In contrast, in the above-described production method, the solid content is supplied from the downstream side and ammonia is supplied from the upstream side based on the gas flow inside the calciner (30). This reduces the degree to which combustion inhibition occurs due to a lack of oxygen for burning the solid content caused by the introduction of ammonia due to differences in combustion speed. Therefore, the above-described production method is useful for suppressing the generation of CO due to incomplete combustion of the solid content when ammonia is supplied into the calciner.

In the cement clinker manufacturing method described above, the solid content may be pulverized coal. The proximate analysis values (air-dry basis) of the pulverized coal may be 25-35% by mass volatile matter, 2-4% by mass moisture, 40-60% by mass fixed carbon, and 10-25% by mass ash. The chemical analysis values (air-dry basis) of the pulverized coal may be 60-75% by mass C (carbon), 3-5% by mass H (hydrogen), 6-9% by mass O (oxygen), 1-3% by mass N (nitrogen), and 0.1-1.0% by mass S (sulfur). The calorific value of the pulverized coal may be 4500-6500 kcal/kg.

The above-mentioned simulation verification confirmed that CO generation is suppressed at least when pulverized coal having these components and calorific value is supplied as solid content from the first supply member (60).

In the cement clinker manufacturing method described above, the solid content may be pulverized coal. The particle size distribution of the pulverized coal may be such that particles having a particle size of 8.00 μm or more and less than 16.00 μm account for 5 to 20 mass% of particles, particles having a particle size of 16.00 μm or more and less than 32.00 μm account for 20 to 40 mass% of particles, particles having a particle size of 32.00 μm or more and less than 64.00 μm account for 20 to 40 mass% of particles, and particles having a particle size of 64.00 μm or more and less than 128.00 μm account for 10 to 30 mass% of particles.

The above-mentioned simulation verification confirmed that CO generation is suppressed at least when pulverized coal having such a particle size distribution is supplied as solid content from the first supply member (60).

In the cement clinker manufacturing method described above, in the second supply step, ammonia may be supplied to the interior (S) of the calciner (30) together with air having an air ratio of 0.1 to 1.0. Because ammonia has a fast combustion rate, its disappearance upstream has little effect on the combustion of solids supplied downstream. In the above method, supplying ammonia together with air having an air ratio of 0.1 to 1.0 more reliably eliminates ammonia immediately after supply. This is therefore useful for suppressing the generation of CO due to incomplete combustion of solids caused by the introduction of ammonia.

The cement clinker manufacturing method described above may further include a third supply step in which one or more third supply members (80) supply oxygen-containing hot gas to the interior (S) of the calciner (30). The temperature of the hot gas may be 700°C to 1000°C. Based on the gas flow inside the calciner (30), the location from which the one or more third supply members (80) supply the hot gas may correspond to the location from which the one or more first supply members (60) supply the thermal energy source containing solids, or may be located upstream of the location from which the one or more first supply members (60) supply the thermal energy source containing solids, and may be located downstream of the location from which the one or more second supply members (70) supply the ammonia. Even if the solids are supplied downstream, the supply of ammonia reduces oxygen, resulting in a slight shortage of oxygen for burning the solids downstream. In the above method, supplying oxygen-containing hot gas from a location corresponding to the location from which the solids are supplied or between the location from which the solids are supplied and the ammonia is supplied promotes combustion of the solids and reduces the amount of unburned solids. Therefore, even when ammonia is introduced, it is useful for suppressing the generation of CO due to incomplete combustion of solids.

In the cement clinker manufacturing method described above, in the third supply step, the extracted gas from the clinker cooler (48), which cools the cement clinker produced in the rotary kiln (40), may be supplied as the hot gas. In this case, the gas used to cool the clinker can be effectively used as hot gas to promote the combustion of the solids.

In the cement clinker manufacturing method described above, the ratio of the calorific value of ammonia supplied from one or more second supply members (70) to the calciner (30) to the total calorific value may be 0.01 to 0.55. The ratio of the calorific value of the thermal energy source containing solids supplied from one or more first supply members (60) to the calciner (30) to the total calorific value may be 0.45 to 0.99. In this case, by setting the ratio of the calorific value of ammonia to the total calorific value to 0.55 or less, it is possible to reduce the occurrence of inhibition of combustion of the solids due to the introduction of ammonia.

The cement clinker manufacturing apparatus (100) includes a rotary kiln (40) that heats cement raw materials to produce cement clinker, a calciner (30) into which exhaust gas from the rotary kiln (40) is introduced and which heats the cement raw materials, one or more first supply members (60) that supply a thermal energy source containing solids to the interior (S) of the calciner (30), and one or more second supply members (70) that supply ammonia to the interior (S) of the calciner (30). Based on the gas flow in the interior (S) of the calciner (30), the position at which the one or more second supply members (70) supply ammonia is located upstream of the position at which the one or more first supply members (60) supply the thermal energy source containing solids. The ratio of the calorific value of the ammonia supplied to the calciner (30) from one or more second supply members (70) to the total calorific value of the thermal energy sources supplied to the calciner (30) from one or more first supply members (60) and one or more second supply members (70) is 0.01 to 0.90. This manufacturing apparatus (100), like the manufacturing method described above, is useful for suppressing the generation of CO due to incomplete combustion of solids when ammonia is supplied to the calciner.

100... manufacturing apparatus (cement clinker manufacturing apparatus), 30... calciner, 40... rotary kiln, 48... clinker cooler, 50... thermal energy source supply unit, 60, 60a, 60b... supply member (first supply member), 70, 70a, 70b... supply member (second supply member), 80... supply member (third supply member), F... gas flow direction.

Claims (6)

a first supplying step of supplying a thermal energy source containing solids by one or more first supply members to an interior of a calciner into which exhaust gas from a rotary kiln that heats cement raw materials to produce cement clinker is introduced;
a second supply step of supplying ammonia to the inside of the calciner using one or more second supply members,
a position at which the one or more second supply members supply the ammonia based on a gas flow inside the calciner is disposed upstream of a position at which the one or more first supply members supply the thermal energy source containing the solid content,
a ratio of a calorific value of the ammonia supplied from the one or more second supply members to the calciner to a total calorific value of the thermal energy source supplied from the one or more first supply members and the one or more second supply members to the calciner is 0.01 to 0.90;
A method for producing cement clinker. the solid content is pulverized coal,
The pulverized coal has proximate analysis values on an air-dry basis of a volatile matter of 25 to 35 mass%, a moisture content of 2 to 4 mass%, a fixed carbon content of 40 to 60 mass%, and an ash content of 10 to 25 mass%,
Chemical analysis values of the pulverized coal on an air-dry basis are: C (carbon) 60 to 75% by mass; H (hydrogen) 3 to 5% by mass; O (oxygen) 6 to 9% by mass; N (nitrogen) 1 to 3% by mass; and S (sulfur) 0.1 to 1.0% by mass;
The calorific value of the pulverized coal is 4500 to 6500 kcal/kg.
The method for producing cement clinker according to claim 1 . the solid content is pulverized coal,
The particle size distribution of the pulverized coal is
5 to 20% by mass of particles having a particle size of 8.00 μm or more and less than 16.00 μm,
20 to 40% by mass of particles having a particle size of 16.00 μm or more and less than 32.00 μm;
particles having a particle size of 32.00 μm or more and less than 64.00 μm are 20 to 40% by mass,
Particles having a particle size of 64.00 μm or more and less than 128.00 μm are 10 to 30% by mass,
The method for producing cement clinker according to claim 1 . The method further includes a third supply step of supplying a hot gas containing oxygen to the inside of the calciner using one or more third supply members,
The temperature of the hot gas is 700°C to 1000°C,
With respect to the gas flow inside the calciner, the position to which the one or more third supply members supply the hot gas is
The one or more first supply members are disposed at a position corresponding to a position where a thermal energy source containing the solid content is supplied, or upstream of the supply position; and
the one or more second supply members are arranged downstream of the position where the ammonia is supplied;
The method for producing cement clinker according to any one of claims 1 to 3 . In the third supply step, extracted gas from a clinker cooler that cools cement clinker produced in the rotary kiln is supplied as the hot gas.
The method for producing cement clinker according to claim 4 . a ratio of a calorific value of the ammonia supplied from the one or more second supply members to the calciner to the total calorific value is 0.01 to 0.55;
A ratio of the calorific value of the thermal energy source containing the solid content supplied from the one or more first supply members to the calciner to the total calorific value is 0.45 to 0.99.
The method for producing cement clinker according to any one of claims 1 to 3 .