Method for producing cement clinker, and apparatus for producing cement clinker

Abstract

When supplying ammonia into a calcination furnace, the generation of CO is suppressed. [Solution] A method for manufacturing cement clinker includes: a first supply step of supplying a thermal energy source containing solids to the inside of a calcination furnace by one or more first supply members; a second supply step of supplying a thermal energy source containing solids to the inside of a calcination furnace by one or more second supply members; and an ammonia supply step of supplying ammonia to the inside of a calcination furnace by one or more third supply members, or supplying ammonia to the inside of the calcination furnace by one or more fourth supply members. The third supply position where one or more third supply members supply ammonia, and the fourth supply position where one or more fourth supply members supply ammonia, are set to positions where ammonia is supplied to an area where the ambient temperature is 900°C or higher.

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a method for manufacturing cement clinker using an NSP kiln equipped with a calcination furnace and a rotary kiln. This manufacturing method includes an introduction step of introducing a thermal energy raw material containing ammonia gas from a first inlet provided in the calcination furnace, and a combustion step of burning the ammonia gas in the calcination furnace. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-28050 [Overview of the project] [Problems that the invention aims to solve]

[0004] This disclosure provides a method for producing cement clinker and an apparatus for producing cement clinker that are useful for suppressing CO generation when supplying ammonia into a calcination furnace. [Means for solving the problem]

[0005] [1] The first supply step includes supplying a thermal energy source containing solids to the inside of a calcination furnace, which calcines cement raw materials before heating in a rotary kiln to produce cement clinker, using one or more first supply members; a second supply step includes supplying a thermal energy source containing solids to the inside of the calcination furnace using one or more second supply members; and an ammonia supply step includes supplying ammonia to the inside of the calcination furnace using one or more third supply members, or supplying ammonia to the inside of the calcination furnace using one or more fourth supply members, wherein, based on the gas flow inside the calcination furnace, the first supply position in which the one or more first supply members supply a thermal energy source containing solids is the same as the supply position in which the one or more second supply members supply a thermal energy source containing solids. A method for manufacturing cement clinker, wherein the third supply position, where one or more third supply members supply ammonia based on the gas flow inside the calcination furnace, is located upstream of the second supply position, and is positioned between the second supply position and the first supply position, and the third supply position is set to supply ammonia to a region where the ambient temperature is 900°C or higher, and the fourth supply position, where one or more fourth supply members supply ammonia based on the gas flow inside the calcination furnace, is located upstream of the first supply position, and is set to supply ammonia to a region where the ambient temperature is 900°C or higher.

[0006] [2] The method for producing cement clinker according to [1], wherein the ratio of the calorific value of ammonia supplied to the calcination furnace in the ammonia supply step to the total calorific value of the thermal energy sources supplied to the calcination furnace in the first supply step, the second supply step, and the ammonia supply step is 0.01 to 0.90.

[0007] [3] The method for producing cement clinker according to [2] above, wherein the ratio of the calorific value of ammonia supplied to the calcination furnace in the ammonia supply step to the total calorific value is 0.01 to 0.55, and the ratio of the calorific value of the thermal energy source containing solids supplied to the calcination furnace in the first supply step and the second supply step to the total calorific value is 0.45 to 0.99.

[0008] [4] A method for producing cement clinker according to any one of [1] to [3] above, wherein in the ammonia supply step, ammonia is supplied to the inside of the calcination furnace together with air having an air ratio of 0.1 to 1.0.

[0009] [5] The method for producing cement clinker according to any one of [1] to [4] above, wherein the solid content supplied in the first supply step and the second supply step is pulverized coal, the industrial analysis values ​​of the pulverized coal on an air-dry basis 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 chemical analysis values ​​of the pulverized coal on an air-dry basis are 60-75% by mass for C (carbon), 3-5% by mass for H (hydrogen), 6-9% by mass for O (oxygen), 1-3% by mass for N (nitrogen), and 0.1-1.0% by mass for S (sulfur), and the calorific value of the pulverized coal is 4500-6500 kcal / kg.

[0010] [6] A method for producing cement clinker according to any one of [1] to [5] above, wherein the solid content supplied in the first supply step and the second supply step is pulverized coal, and the particle size distribution of the pulverized coal is such that 5 to 20% by mass consists of particles having a particle size of 8.00 μm or more and less than 16.00 μm, 20 to 40% by mass consists of particles having a particle size of 16.00 μm or more and less than 32.00 μm, 20 to 40% by mass consists of particles having a particle size of 32.00 μm or more and less than 64.00 μm, and 10 to 30% by mass consists of particles having a particle size of 64.00 μm or more and less than 128.00 μm.

[0011] [7] A method for manufacturing cement clinker according to any one of [1] to [6] above, further comprising a hot gas supply step of supplying hot gas containing oxygen to the inside of the calcination furnace by one or more fifth supply members, wherein the temperature of the hot gas is 700°C to 1000°C, and the position where the one or more fifth supply members supply the hot gas is a position corresponding to the second supply position, or is located between the second supply position and the first supply position, with reference to the gas flow inside the calcination furnace.

[0012] [8] The method for producing cement clinker according to [7], wherein in the heat gas supply step, extracted gas from a clinker cooler that cools the cement clinker produced in the rotary kiln is supplied as the heat gas.

[0013] [9] The method for producing cement clinker according to any one of [1] to [8] above, wherein the calcination furnace is a direct calcination furnace into which exhaust gas from the rotary kiln is directly introduced.

[0014]

[10] A rotary kiln that heats cement raw materials to produce cement clinker; a calcination furnace that calcines the cement raw materials before heating by the rotary kiln; one or more first supply members that supply a thermal energy source containing solids to the inside of the calcination furnace; one or more second supply members that supply a thermal energy source containing solids to the inside of the calcination furnace; and an ammonia supply unit that either supplies ammonia to the inside of the calcination furnace by one or more third supply members, or supplies ammonia to the inside of the calcination furnace by one or more fourth supply members, with reference to the gas flow inside the calcination furnace, the first supply position where the one or more first supply members supply a thermal energy source containing solids is A cement clinker manufacturing apparatus, wherein a third supply position, where one or more third supply members supply ammonia based on the gas flow inside the calcination furnace, is located upstream of a second supply position for supplying a ghee source, and the third supply position, where one or more third supply members supply ammonia based on the gas flow inside the calcination furnace, is located at a position corresponding to the second supply position or between the second supply position and the first supply position, and the third supply position is set to supply ammonia to a region where the ambient temperature is 900°C or higher; and a fourth supply position, where one or more fourth supply members supply ammonia based on the gas flow inside the calcination furnace, is located at a position corresponding to the first supply position or upstream of the first supply position, and the fourth supply position is set to supply ammonia to a region where the ambient temperature is 900°C or higher. [Effects of the Invention]

[0015] According to this disclosure, a method for producing cement clinker and an apparatus for producing cement clinker are provided, which are useful for suppressing the generation of CO when ammonia is supplied into a calcination furnace. [Brief explanation of the drawing]

[0016] [Figure 1] Figure 1 is a schematic diagram illustrating a cement clinker manufacturing apparatus. [Figure 2]Figure 2 is a side view schematically illustrating a calcination furnace and a thermal energy source supply unit. [Figure 3] Figure 3 is a schematic view illustrating the arrangement of supply members. [Figure 4] Figure 4 is a side view schematically illustrating a calcination furnace and a thermal energy source supply unit. [Figure 5] Figure 5 is a schematic view illustrating the arrangement of supply members. [Figure 6] Figure 6 is a schematic view illustrating a direct-type calcination furnace. [Figure 7] Figure 7(a) and Figure 7(b) are schematic views illustrating calcination furnaces of a type different from the direct-type calcination furnace. [Figure 8] Figure 8 is a diagram illustrating simulation results. [Figure 9] Figure 9 is a graph illustrating simulation results. [Mode for Carrying Out the Invention]

[0017] Hereinafter, an embodiment will be described with reference to the drawings. In the description, the same reference numerals are assigned to the same elements or elements having the same function, and redundant descriptions are omitted. The following embodiment is an example for describing the present disclosure, and is not intended to limit the present disclosure to the following contents. In addition, the dimensional ratio of each element is not limited to the illustrated ratio.

[0018] First, an apparatus and a method for producing cement clinker according to a first embodiment will be described with reference to Figures 1 to 3.

[0019] [Cement Clinker Production Apparatus] Figure 1 schematically shows a cement clinker manufacturing apparatus according to one embodiment. The manufacturing apparatus 1 (cement clinker manufacturing apparatus) shown in Figure 1 is an apparatus that manufactures cement clinker, an intermediate cement product, by firing cement raw materials. The manufacturing apparatus 1 is equipped with an NSP (New Suspension Preheater) type preheating device. The manufacturing apparatus 1 is also called an NSP kiln. The manufacturing apparatus 1 includes, for example, a preheating device 2, a rotary kiln 4, and a clinker cooler 6.

[0020] The preheating device 2 functions as a preheater for preheating and calcining the cement raw materials. The preheating device 2 includes cyclones C1, C2, C3, and C4 and a calcination furnace 10. The cement raw materials may include two or more selected from the group consisting of, for example, incinerated ash, coal ash, limestone, iron source, and slag. The cement raw materials are introduced from the connection between cyclone C1 and cyclone C2, heated as they flow through cyclone C1, cyclone C2, cyclone C3, calcination furnace 10, and cyclone C4, and introduced to the kiln end 4a of the rotary kiln 4. When introduced to the kiln end 4a of the rotary kiln 4, the cement raw materials are heated to, for example, 850°C to 1000°C, preferably 850°C to 900°C. A chute 3 may be provided between cyclone C3 and the calcination furnace 10 for feeding the cement raw materials into the calcination furnace 10.

[0021] The calcination furnace 10 and the kiln end 4a of the rotary kiln 4 are connected by a rising duct 5. Exhaust gas from the rotary kiln 4 is introduced into the calcination furnace 10 via the rising duct 5. The temperature of the exhaust gas introduced from the rotary kiln 4 into the calcination furnace 10 may be around 1000°C to 1200°C, 1050°C to 1150°C, or 1100°C. The exhaust gas generated in the rotary kiln 4 includes combustion exhaust gas. The exhaust gas from the rotary kiln 4 flows through the calcination furnace 10, cyclone C4, cyclone C3, cyclone C2, and cyclone C1, where heat exchange takes place between the exhaust gas and the cement raw materials.

[0022] The calcination furnace 10 calcines the cement raw materials before heating by the rotary kiln 4. The calcination furnace 10 calcines the cement raw materials using exhaust gas from the rotary kiln 4 and a heat energy source supplied to the calcination furnace 10. In other words, the calcination furnace 10 is a heating furnace that heats the cement raw materials. At least a portion of the calcination furnace 10 is formed in a cylindrical shape (see also Figure 2). In at least a portion of the calcination furnace 10, the side walls of the calcination furnace 10 may extend along the central axis of the calcination furnace 10. The central axis of the calcination furnace 10 is a hypothetical line, for example, a line extending vertically.

[0023] A probe 8 is connected to the rising duct 5 to extract exhaust gas from within the rising duct 5. Downstream of the probe 8, a chlorine bypass system is installed, which includes a cooler and a bag filter, and collects dust contained in the extracted gas (exhaust gas) from the probe 8. By installing the chlorine bypass system, volatile components such as chlorine compounds and alkalis can be reduced from within the manufacturing apparatus 1. The probe 8 may also be connected to the kiln end 4a instead of the rising duct 5, or to the boundary between the rising duct 5 and the kiln end 4a.

[0024] The rotary kiln 4 produces cement clinker (hereinafter sometimes simply referred to as "clinker") by firing cement raw materials. In other words, the rotary kiln 4 is a heating furnace that heats cement raw materials. The rotary kiln 4 is equipped with a burner 4b for burning fuel. The burner 4b is located at the downstream end of the rotary kiln 4 (the end closer to the clinker cooler 6). The combustion in the burner 4b heats the cement raw materials inside the rotary kiln 4 to, for example, 1300°C to 1450°C. In the rotary kiln 4, the cement raw materials, after preheating and calcination, are heated by the combustion in the burner 4b to become clinker.

[0025] The clinker produced in the rotary kiln 4 is discharged into the clinker cooler 6. The clinker cooler 6 cools the clinker with cooling air, such as outside air. After being cooled in the clinker cooler 6, the clinker is discharged from the manufacturing apparatus 1. A portion of the gas used to cool the clinker in the clinker cooler 6 may be introduced into the calcination furnace 10 as extracted gas. The temperature of the extracted gas introduced from the clinker cooler 6 into the calcination furnace 10 may be 700°C to 1000°C, 750°C to 1000°C, or 800°C to 900°C. The introduction of a thermal energy source into the calcination furnace 10 will be described below.

[0026] The manufacturing apparatus 1 includes a heat energy source supply unit 20. The heat energy source supply unit 20 is a part that supplies two or more heat energy sources to the inside of the calcination furnace 10. Figure 2 schematically shows the calcination furnace 10 and the heat energy source supply unit 20 as viewed from the side, and Figure 3 schematically shows a part of the heat energy source supply unit 20. From the viewpoint of reducing carbon dioxide emissions, ammonia (ammonia gas) is introduced into the calcination furnace 10 as one of the heat energy sources. In addition to the calcination furnace 10, ammonia (ammonia gas) may also be introduced into the rotary kiln 4 as one of the heat energy sources. In the calcination furnace 10, ammonia gas is burned. In Figure 2, etc., the "Z" axis direction represents the vertical direction, and "S" represents the space inside the calcination furnace 10.

[0027] <Supply of thermal energy sources containing solids> The thermal energy source supply unit 20 includes one or more supply members 30 (first supply member). In Figure 2, etc., one supply member 30 is shown, but two or more (for example, two) supply members 30 may be provided. The supply member 30 is a member (burner) that supplies a thermal energy source containing solid matter to the inside of the calcination furnace 10. Solid matter refers to a solid thermal energy source. The supply member 30 may supply solid matter and combustion air to the inside of the calcination furnace 10.

[0028] The solids include, for example, at least one of pulverized coal and waste. The waste supplied to the inside of the calcination furnace 10 may include one or more types of waste such as waste plastic, RDF (Refuse Derived Fuel), or meat and bone meal. The supply member 30 may supply pulverized coal and combustion air, waste and combustion air, or pulverized coal, waste, and combustion air. In the following, we will assume that pulverized coal and combustion air are supplied from the supply member 30.

[0029] The end of the supply member 30 is provided with an inlet 32 ​​for discharging (blowing in) pulverized coal as a solid component and combustion air into the calcination furnace 10 (see Figure 3). The end of the supply member 30 including the inlet 32 ​​functions as a nozzle. The end of the supply member 30 that functions as a nozzle may be installed horizontally. The above end of the supply member 30 may be connected to the side wall of the calcination furnace 10. Note that in Figure 3, the inclination of the side wall of the calcination furnace 10 shown in Figure 2 is omitted.

[0030] The supply member 30 may transport pulverized coal to its inlet 32 ​​using transport air. The supply member 30 may also supply pulverized coal (pulverized coal and transport air) and combustion air separately to the inside of the calcination furnace 10. In this case, the inlet 32 ​​at the end of the supply member 30 may include one or more openings for discharging pulverized coal and one or more openings for discharging combustion air. When pulverized coal and combustion air are supplied separately, the pulverized coal and combustion air do not merge during transport by the supply member 30.

[0031] If two or more supply members 30 are provided, the two or more supply members 30 shall have similar functions and configurations. In the direction in which gas flows inside the calcination furnace 10 (hereinafter referred to as the "flow direction F"), the inlets 32 of the two or more supply members 30 may be arranged at corresponding positions to each other. In the flow direction F, for the two inlets to be arranged at corresponding positions to each other means that at least a portion of one inlet is in the same position as at least a portion of the other inlet. The two or more supply members 30 may be arranged at different positions to each other in the circumferential direction around the central axis of the calcination furnace 10.

[0032] The flow direction F is defined as the direction from the inlet 10a of the calcination furnace 10 (exhaust gas from the rotary kiln 4) toward the outlet 10b of the calcination furnace 10. In the examples shown in Figures 2 and 3, the flow direction F is the direction from bottom to top along the vertical. Although the combustion gas, including the exhaust gas from the rotary kiln 4, may flow in a swirling motion inside the calcination furnace 10, the flow direction F is defined by the positional relationship between the inlet 10a and the outlet 10b of the calcination furnace 10.

[0033] When the flow direction F is vertical, the inlet 10a of the calcination furnace 10 indicates the lowest stage of the calcination furnace, where the air velocity of the exhaust gas (kiln exhaust gas) from the rotary kiln 4 decreases sharply. Specifically, a sharp decrease in air velocity means that the flow velocity becomes less than half. The outlet 10b of the calcination furnace 10 indicates the uppermost stage of the calcination furnace, which corresponds to the top of the duct 12 that leads the exhaust gas from the calcination furnace 10 to the cyclone C4, as illustrated in Figure 2. Note that, unlike the example shown in Figure 2, if the end of the duct 12 is connected to the top of the calcination furnace 10, the outlet 10b of the calcination furnace 10 corresponds to the connection point between the calcination furnace 10 and the duct 12. When two or more supply members 30 are provided, the inlets 32 of the two or more supply members 30 may be arranged at corresponding height positions.

[0034] The thermal energy source supply unit 20 includes one or more supply members 30, in addition to one or more supply members 40 (second supply members). In Figure 2, etc., one supply member 40 is shown, but two or more (for example, two) supply members 40 may be provided. The supply member 40 is a member (burner) that supplies a thermal energy source containing solid matter to the inside of the calcination furnace 10. The supply member 40 may supply solid matter and combustion air to the inside of the calcination furnace 10. The supply member 40 and the supply member 30 may supply the same type of solid matter, or they may supply different types of solid matter. In the following, it will be assumed that pulverized coal and combustion air are supplied from the supply member 40.

[0035] The end of the supply member 40 is provided with an inlet 42 for discharging (blowing in) pulverized coal as a solid component and combustion air into the calcination furnace 10 (see Figure 3). The end of the supply member 40 including the inlet 42 functions as a nozzle. The end of the supply member 40 that functions as a nozzle may be installed horizontally. The end of the supply member 40 may be connected to the side wall of the calcination furnace 10.

[0036] The supply member 40 may transport pulverized coal to its inlet 42 using transport air. The supply member 40 may also supply pulverized coal (pulverized coal and transport air) and combustion air separately to the inside of the calcination furnace 10. In this case, the inlet 42 at the end of the supply member 40 may include one or more openings for discharging pulverized coal and one or more openings for discharging combustion air. When pulverized coal and combustion air are supplied separately, the pulverized coal and combustion air do not merge during transport by the supply member 40.

[0037] If two or more supply members 40 are provided, the two or more supply members 40 have similar functions and configurations. In the flow direction F, the inlets 42 of the two or more supply members 40 may be arranged at corresponding positions to each other. In the flow direction F, two inlets being arranged at corresponding positions to each other means that at least a portion of one inlet is in the same position as at least a portion of the other inlet. If the flow direction F is vertical, the inlets 42 of the two or more supply members 40 may be arranged at corresponding height positions to each other. The two or more supply members 40 may be arranged at different positions in the circumferential direction around the central axis of the calcination furnace 10.

[0038] Here, we will explain the relative positions of one or more supply members 30 and one or more supply members 40. In the following, we will focus on one supply member 30 and one supply member 40 and explain their relative positions, but the same relative positions hold true for all combinations of supply members 30 and 40.

[0039] In the flow direction F, the position where the supply member 30 supplies a thermal energy source containing pulverized coal (first supply position) is located upstream of the position where the supply member 40 supplies a thermal energy source containing pulverized coal (second supply position). The position where the supply member 30 supplies a thermal energy source containing pulverized coal corresponds to the position of the inlet 32 ​​of the supply member 30, and this position may hereafter be referred to as the "supply position of the supply member 30". The position where the supply member 40 supplies a thermal energy source containing pulverized coal corresponds to the position of the inlet 42 of the supply member 40, and this position may hereafter be referred to as the "supply position of the supply member 40".

[0040] When the flow direction F is aligned vertically, the height of the supply position of the supply member 30 may be lower than the height of the supply position of the supply member 40. The uppermost position (the point located at the very top) of the inlet 32 ​​of the supply member 30 may be lower than the lowermost position (the point located at the very bottom) of the inlet 42 of the supply member 40.

[0041] An example of the composition, calorific value, and particle size distribution of pulverized coal supplied from one or more supply members 30 and one or more supply members 40 will be described. The industrial analysis values ​​(mass %: air-dry basis) of the volatile matter, moisture, fixed carbon, and ash content of the pulverized coal may be within the following ranges. (a) The industrial analysis value of volatile matter may be 25% by mass or more, 26% by mass or more, 27% by mass or more, or 28% by mass or more. The industrial analysis value of volatile matter may be 35% by mass or less, 34% by mass or less, 33% by mass or less, or 32% by mass or less. For example, the industrial analysis value of volatile matter is 25-35% by mass or 28-32% by mass. (b) The industrial analysis value of moisture may be 2.0% by mass or more, 2.2% by mass or more, 2.4% by mass or more, or 2.6% by mass or more. The industrial analysis value of moisture may be 4.0% by mass or less, 3.8% by mass or less, 3.6% by mass or less, or 3.4% by mass or less. For example, the industrial analysis value of moisture is 2.0 to 4.0% by mass, or 2.6% by mass or 3.4% by mass. (c) The industrial analysis value of fixed carbon may be 40% by mass or more, 42% by mass or more, 44% by mass or more, or 46% by mass or more. The industrial analysis value of fixed carbon may be 60% by mass or less, 58% by mass or less, 56% by mass or less, or 54% by mass or less. For example, the industrial analysis value of fixed carbon is 40-60% by mass or 46-54% by mass. (d) The industrial analysis value of the ash content may be 10% by mass or more, 11% by mass or more, 12% by mass or more, or 13% by mass or more. The industrial analysis value of the ash content may be 25% by mass or less, 24% by mass or less, 23% by mass or less, or 22% by mass or less. For example, the industrial analysis value of the ash content is 10-25% by mass or 13-22% by mass.

[0042] For example, regarding the industrial analysis values ​​of the components of pulverized coal, volatile matter is 25-35% by mass, moisture is 2-4% by mass, fixed carbon is 40-60% by mass, and ash is 10-25% by mass. The industrial analysis values ​​of the components of pulverized coal are analytical values ​​measured by the test methods described in JIS M8812 "Coal and coke - Industrial analysis methods".

[0043] The chemical analysis values ​​(mass percent: air-dry basis) for C (carbon), H (hydrogen), O (oxygen), N (nitrogen), and S (sulfur) of pulverized coal may be within the following ranges. (a) The chemical analysis value of C may be 60% by mass or more, 61% by mass or more, 62% by mass or more, or 63% by mass or more. The chemical analysis value of C may be 75% by mass or less, 74% by mass or less, 73% by mass or less, or 72% by mass or less. In one example, the chemical analysis value of C is 60-75% by mass or 63-72% by mass. (b) The chemical analysis value of H may be 3.0% by mass or more, 3.2% by mass or more, 3.4% by mass or more, or 3.6% by mass or more. The chemical analysis value of H may be 5.0% by mass or less, 4.8% by mass or less, 4.6% by mass or less, or 4.4% by mass or less. In one example, the chemical analysis value of H is 3 to 5% by mass, or 3.6 to 4.4% by mass. (c) The chemical analysis value of O may be 6.0% by mass or more, 6.2% by mass or more, 6.4% by mass or more, or 6.6% by mass or more. The chemical analysis value of O may be 9.0% by mass or less, 8.8% by mass or less, 8.6% by mass or less, or 8.4% by mass or less. In one example, the chemical analysis value of O is 6-9% by mass or 6.6-8.4% by mass. (d) The chemical analysis value of N may be 1.0% by mass or more, 1.1% by mass or more, 1.2% by mass or more, or 1.3% by mass or more. The chemical analysis value of N may be 3.0% by mass or less, 2.8% by mass or less, 2.6% by mass or less, or 2.4% by mass or less. In one example, the chemical analysis value of N is 1 to 3% by mass, or 1.3 to 2.4% by mass. (e) The chemical analysis value of S may be 0.1% by mass or more, 0.2% by mass or more, 0.3% by mass or more, or 0.4% by mass or more. The chemical analysis value of S may be 1.0% by mass or less, 0.9% by mass or less, 0.8% by mass or less, or 0.7% by mass or less. In one example, the chemical analysis value of S is 0.1 to 1.0% by mass, or 0.4 to 0.7% by mass.

[0044] For example, regarding the chemical analysis values ​​(air-dry basis) of the components of pulverized coal, C is 60-75% by mass, H is 3-5% by mass, O is 6-9% by mass, N is 1-3% by mass, and S is 0.1-1.0% by mass. The chemical analysis values ​​(air-dry basis) of the components of pulverized coal are analytical values ​​measured by the test methods described in JIS M8813 "Coal and coke - Elemental analysis methods" and JIS M8810 "Coal and coke - General rules for sampling, analysis and test methods".

[0045] The chemical analysis values ​​(mass %) of C, H, O, N, and S in pulverized coal may be within the following ranges. (a) The chemical analysis value of C may be 75% by mass or more, 76% by mass or more, 77% by mass or more, or 78% by mass or more. The chemical analysis value of C may be 90% by mass or less, 89% by mass or less, 88% by mass or less, or 87% by mass or less. In one example, the chemical analysis value of C is 75-90% by mass or 78-88% by mass. (b) The chemical analysis value of H may be 4.0% by mass or more, 4.2% by mass or more, 4.4% by mass or more, or 4.6% by mass or more. The chemical analysis value of H may be 6.0% by mass or less, 5.8% by mass or less, 5.6% by mass or less, or 5.4% by mass or less. In one example, the chemical analysis value of H is 4-6% by mass or 4.6-5.4% by mass. (c) The chemical analysis value of O may be 8.0% by mass or more, 8.2% by mass or more, 8.4% by mass or more, or 8.6% by mass or more. The chemical analysis value of O may be 11.0% by mass or less, 10.8% by mass or less, 10.6% by mass or less, or 10.4% by mass or less. In one example, the chemical analysis value of O is 8 to 11% by mass, or 8.6 to 10.4% by mass. (d) The chemical analysis value of N may be 1.0% by mass or more, 1.1% by mass or more, 1.2% by mass or more, or 1.3% by mass or more. The chemical analysis value of N may be 3.0% by mass or less, 2.9% by mass or less, 2.8% by mass or less, or 2.7% by mass or less. In one example, the chemical analysis value of N is 1 to 3% by mass, or 1.3 to 2.7% by mass. (e) The chemical analysis value of S may be 0.1% by mass or more, 0.2% by mass or more, 0.3% by mass or more, or 0.4% by mass or more. The chemical analysis value of S may be 1.0% by mass or less, 0.9% by mass or less, 0.8% by mass or less, or 0.7% by mass or less. In one example, the chemical analysis value of S is 0.1 to 1.0% by mass, or 0.4 to 0.7% by mass.

[0046] For example, regarding the chemical analysis values ​​of the components of pulverized coal (anhydrous, ash-free basis), C is 75-90% by mass, H is 4-6% by mass, O is 8-11% by mass, N is 1-3% by mass, and S is 0.1-1.0% by mass. The chemical analysis values ​​of the components of pulverized coal (air-dry basis) are analytical values ​​measured by the test methods described in JIS M8813 "Coal and coke - Elemental analysis methods" and JIS M8810 "Coal and coke - General rules for sampling, analysis and test methods".

[0047] The calorific value of pulverized coal (more specifically, the lower heating value of pulverized coal on an arrival basis) 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 pulverized coal means the lower heating value (on an arrival basis). The calorific value of 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. For example, the calorific value of pulverized coal is 4500 to 6500 kcal / kg, or 5100 to 5900 kcal / kg. The calorific value of pulverized coal, i.e., the lower heating value (on an arrival basis), is measured by the test method described in JIS M8814 "Coal and coke - Method for measuring total calorific value and calculation method for net calorific value using a bomb calorimeter".

[0048] The particle size distribution (mass percentage for each particle size category) of pulverized coal may be within the following range. The mass percentage (mass%) for each particle size category refers to the ratio of the mass of particles in that particle size category to the total mass of pulverized coal. (a) Particles with a particle size of less than 8.00 μm may be present in amounts of 15% by mass or less, 13% by mass or less, 11% by mass or less, or 9% by mass or less. Particles with a particle size of less than 8.00 μm may not be present at all. (b) Particles with a particle size of 8.00 μm or more and less than 16.00 μm may be present in amounts of 5% by mass or more, 6% by mass or more, 7% by mass or more, or 8% by mass or more. Particles with a particle size of 8.00 μm or more and less than 16.00 μm may be present in amounts of 20% by mass or less, 19% by mass or less, 18% by mass or less, or 17% by mass or less. In one example, particles with a particle size of 8.00 μm or more and less than 16.00 μm may be present in amounts of 5 to 20% by mass, or 8 to 17% by mass. (c) Particles with a particle size of 16.00 μm or more and less than 32.00 μm may be present in amounts of 20% by mass or more, 22% by mass or more, 24% by mass or more, or 26% by mass or more. Particles with a particle size of 16.00 μm or more and less than 32.00 μm may be present in amounts of 40% by mass or less, 38% by mass or less, 36% by mass or less, or 34% by mass or less. In one example, particles with a particle size of 16.00 μm or more and less than 32.00 μm are present in amounts of 20-40% by mass or 26-34% by mass. (d) Particles with a particle size of 32.00 μm or more and less than 64.00 μm may be present in amounts of 20% by mass or more, 22% by mass or more, 24% by mass or more, or 26% by mass or more. Particles with a particle size of 32.00 μm or more and less than 64.00 μm may be present in amounts of 40% by mass or less, 38% by mass or less, 36% by mass or less, or 34% by mass or less. In one example, particles with a particle size of 32.00 μm or more and less than 64.00 μm may be present in amounts of 20-40% by mass or 26-34% by mass. (e) Particles with a particle size of 64.00 μm or more and less than 128.00 μm may be present in amounts of 10% by mass or more, 12% by mass or more, 14% by mass or more, or 16% by mass or more. Particles with a particle size of 64.00 μm or more and less than 128.00 μm may be present in amounts of 30% by mass or less, 28% by mass or less, 26% by mass or less, or 24% by mass or less. In one example, particles with a particle size of 64.00 μm or more and less than 128.00 μm may be present in amounts of 10-30% by mass or 16-24% by mass. (f) Particles with a particle size of 128.00 μm or larger may be present in amounts of 10% by mass or less, 9% by mass or less, 8% by mass or less, or 7% by mass or less. The product may not contain any particles with a particle size of 128.00 μm or larger.

[0049] In one example, regarding the particle size distribution of pulverized coal, 5 to 20% by mass consist of particles with a particle size of 8.00 μm or more and less than 16.00 μm, 20 to 40% by mass consist of particles with a particle size of 16.00 μm or more and less than 32.00 μm, 20 to 40% by mass consist of particles with a particle size of 32.00 μm or more and less than 64.00 μm, and 10 to 30% by mass consist of particles with a particle size of 64.00 μm or more and less than 128.00 μm. In this case, at least one of the particles with a particle size of less than 8.00 μm and the particles with a particle size of 128.00 μm or more may be contained in the pulverized coal, and neither of these particles may be contained in the pulverized coal. The particle size distribution (particle size) of pulverized coal is measured by the test method described in JIS Z 8825 "Particle size analysis - Laser diffraction and scattering method".

[0050] <Supply of ammonia> The thermal energy source supply unit 20 includes one or more supply members 30 and one or more supply members 40, in addition to one or more supply members 50 (fourth supply member). In Figure 2, etc., one supply member 50 is shown, but two or more (for example, two) supply members 50 may be provided. The supply member 50 is a member (burner) that supplies ammonia to the inside of the calcination furnace 10.

[0051] The supply member 50 is configured to supply an ammonia-containing gas containing ammonia. The ammonia-containing gas supplied from the supply member 50 may be ammonia gas alone, or it may be a mixture of ammonia gas and other gases such as air or methane.

[0052] The supply member 50 is provided with an inlet 52 at one end for discharging (blowing in) ammonia (ammonia-containing gas) into the calcination furnace 10. The end of the supply member 50, including the inlet 52, functions as a nozzle. The inlet 52 of the supply member 50 may have one or more openings for introducing ammonia. In addition to one or more openings for discharging ammonia, the inlet 52 at the end of the supply member 50 may include one or more openings for discharging combustion air. The end of the supply member 50 that functions as a nozzle may be installed horizontally. The end of the supply member 50 may be connected to the side wall of the calcination furnace 10.

[0053] If two or more supply members 50 are provided, the two or more supply members 50 shall have similar functions and configurations. In the flow direction F, the inlets 52 of the two or more supply members 50 may be arranged at corresponding positions. If the flow direction F is vertical, the inlets 52 of the two or more supply members 50 may be arranged at corresponding height positions. The two or more supply members 50 may be arranged at different positions in the circumferential direction around the central axis of the calcination furnace 10.

[0054] The supply member 50 may supply ammonia together with combustion air to the inside of the calcination furnace 10. In the supply member 50, the ammonia and combustion air may be combined before being introduced into the inside of the calcination furnace 10, or they may be supplied separately without being combined.

[0055] The air-to-aqueous ratio of the combustion air supplied together with ammonia from the supply member 50 is, for example, 0.1 to 1.0. The air-to-aqueous ratio for ammonia combustion is determined by dividing the amount of air supplied to burn ammonia by the theoretical amount of combustion air for ammonia. The theoretical amount of combustion air for ammonia is determined by dividing the theoretical amount of combustion oxygen for ammonia by the ratio of oxygen in the air (0.21). The theoretical amount of combustion oxygen for ammonia is determined by multiplying the amount of substance of ammonia by 3 / 4 based on the following equation (1). NH3+3 / 4O2→ 1 / 2N2+3 / 2H2O ···(1)

[0056] The air-to-air ratio of the combustion air from the supply member 50 may be 0.15 or higher, 0.2 or higher, or 0.3 or higher, from the viewpoint of promoting ammonia combustion. The air-to-air ratio of the combustion air from the supply member 50 may be 0.9 or lower, 0.8 or lower, or 0.75 or lower, from the viewpoint of efficiently introducing air. The air-to-air ratio of the combustion air from the supply member 50 may be 0.3 to 1.0, or 0.5 to 1.0. In one example, exhaust gas from a chlorine bypass system is introduced as combustion air from the supply member 50.

[0057] The supply member 50 may continuously supply ammonia-containing gas during the period in which the calcination furnace 10 is operating, or it may supply ammonia-containing gas only for a portion of the period in which the calcination furnace 10 is operating.

[0058] A portion of the ammonia-containing gas supplied from the supply member 50 may be used as a thermal energy source, and another portion may be used for denitrification. That is, the reaction may occur not only as shown in equation (2) below, but also as shown in equation (3). NH3 + 1 / 4O2 → 1 / 2N2 + 3 / 2H2O (2) NH3 + NO + 1 / 4O2 → N2 + 3 / 2H2O (3) Since the calcination furnace 10 has a temperature range in which both the combustion reaction and the denitrification reaction can proceed, it can carry out both the combustion reaction and the denitrification reaction of ammonia. This makes it possible to reduce the emissions of both carbon dioxide and nitrogen oxides.

[0059] The thermal energy source supply unit 20 may supply various thermal energy sources to the inside of the calcination furnace 10 such that the heat generation ratio defined below is between 0.01 and 0.90. Heat generation ratio: The ratio of the heat generation of ammonia supplied by one or more supply members 50 to the total heat generation of the thermal energy sources supplied by one or more supply members 30, one or more supply members 40, and one or more supply members 50.

[0060] The above total calorific value is the sum of the calorific values ​​of all thermal energy sources supplied from one or more supply members 30, the calorific values ​​of all thermal energy sources supplied from one or more supply members 40, and the calorific values ​​of all thermal energy sources supplied from one or more supply members 50. The calorific value of the thermal energy sources supplied from one or more supply members 50 may be the calorific value of all ammonia supplied from one or more supply members 50. The calorific value of ammonia (lower heating value on an anhydrous basis) 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.

[0061] The above calorific value ratio may be 0.05 or higher, 0.1 or higher, 0.15 or higher, or 0.20 or higher, from the viewpoint of promoting the effective utilization of ammonia. The above calorific value ratio may be 0.7 or lower, 0.55 or lower, 0.50 or lower, 0.45 or lower, 0.4 or lower, 0.35 or lower, or 0.3 or lower, from the viewpoint of suppressing combustion inhibition of solids caused by ammonia. The above 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 30 and one or more supply members 40 to the total calorific value may be 0.45 to 0.99. The above 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 30 and one or more supply members 40 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.

[0062] Here, we will explain the relative positions of one or more supply members 50 and one or more supply members 30. In the following, we will focus on one supply member 50 and one supply member 30 and explain their relative positions, but the same relative positions hold true for all combinations of supply members 50 and supply members 30.

[0063] The supply member 50 is formed separately from the supply member 30. That is, the supply member 50 is physically separated from the supply member 30. The supply member 50 discharges ammonia from a different position than the position where the supply member 30 supplies the thermal energy source. In other words, the position where the supply member 30 supplies pulverized coal to the inside of the calcination furnace 10 and the position where the supply member 50 supplies ammonia-containing gas to the inside of the calcination furnace 10 are different from each other.

[0064] In the flow direction F, the position where the supply member 50 supplies ammonia (the fourth supply position) is either the same as the supply position of the supply member 30 (the position where the supply member 30 supplies a thermal energy source including pulverized coal), or it is located upstream of the supply position of the supply member 30. The position where the supply member 50 supplies ammonia corresponds to the position of the inlet 52 of the supply member 50, and this position may hereafter be referred to as the "supply position of the supply member 50".

[0065] When the flow direction F is aligned vertically, the height of the supply position of the supply member 50 is the same as, or lower than, the height of the supply position of the supply member 30. At least a portion of the inlet 52 of the supply member 50 may be at the same height as at least a portion of the inlet 32 ​​of the supply member 30. Alternatively, the uppermost position (the point located at the very top) of the inlet 52 of the supply member 50 may be lower than the lowest position (the point located at the very bottom) of the inlet 32 ​​of the supply member 30. In the circumferential direction around the central axis of the calcination furnace 10, the positional relationship between the supply member 50 and the supply member 30 may be set in any way, as long as these members can be installed.

[0066] The supply position of the supply member 50 is set to a location where ammonia is supplied to a region inside the calcination furnace 10 where the ambient temperature is 900°C or higher (hereinafter defined as "region R"). Being set to a location where ammonia is supplied to region R means that the arithmetic mean of the temperature measurements at multiple measurement points in the supply position cross-section, as defined below, is 900°C or higher. Supply position cross-section: A cross-section within the calcination furnace 10 at a position corresponding to the supply position of the supply member 50 in the flow direction F, and which is perpendicular to the flow direction F.

[0067] When the flow direction F is along the vertical direction, the supply position cross section is a horizontal cross section located at the same height as the supply position of the supply member 50 inside the calcination furnace 10. The ambient temperature of region R (the region inside the calcination furnace 10 where ammonia is supplied from the supply member 50) may be 910°C or higher, 920°C or higher, or 930°C or higher. The ambient temperature of region R (the region inside the calcination furnace 10 where ammonia is supplied from the supply member 50) may be 1000°C or lower, 990°C or lower, 980°C or lower, or 970°C or lower. In one example, the ambient temperature of region R is 900°C to 1000°C, 910°C to 990°C, or 930°C to 970°C.

[0068] In Figures 2 and 3, in the flow direction F, the position of the supply member 50 is indicated by "A" and the total length of the calcination furnace 10 is indicated by "L", with the inlet 10a of the calcination furnace 10 being the reference point (0). The position of the supply member 50 in the flow direction F is preferably set such that "A / L" satisfies the following ranges: A / L may be 0.05 or more, 0.06 or more, 0.07 or more, 0.08 or more, or 0.09 or more. A / L may be 0.20 or less, 0.18 or less, 0.16 or less, 0.14 or less, or 0.12 or less. In one example, A / L is 0.05 to 0.20, 0.06 to 0.18, or 0.09 to 0.12.

[0069] The total length "L" corresponds to the distance in the flow direction F between the inlet 10a and the outlet 10b. The position "A" of the supply member 50 corresponds to the distance in the flow direction F between the inlet 10a and the supply position of the supply member 50 (see also Figure 3). The supply position of the supply member 50 is defined by the center position of the inlet 52. If two or more supply members 50 are provided, the position "A" (the supply position of the supply member 50) may be calculated using the arithmetic mean of the center positions of the inlet 52s of the two or more supply members 50.

[0070] In the flow direction F, when the distance between the inlet 10a and the supply position of the supply member 30 is "c1", c1 / L may be 0.05 or more, 0.06 or more, 0.07 or more, 0.08 or more, or 0.09 or more. A / L may be 0.20 or less, 0.18 or less, 0.16 or less, 0.14 or less, or 0.12 or less. The supply position of the supply member 30 is defined by the center position of the inlet 32. If two or more supply members 30 are provided, the distance "c1" (supply position of the supply member 30) may be calculated using the arithmetic mean of the center positions of the inlet 32 ​​of the two or more supply members 30.

[0071] In the flow direction F, when the distance between the inlet 10a and the supply position of the supply member 40 is "c2", c2 / L may be 0.16 or more, 0.18 or more, 0.19 or more, or 0.20 or more. c2 / L may also be 0.30 or less, 0.28 or less, 0.26 or less, 0.24 or less, or 0.22 or less. The supply position of the supply member 40 is defined by the center position of the inlet 42. If two or more supply members 40 are provided, the distance "c2" (supply position of the supply member 40) may be calculated using the arithmetic mean of the center positions of the inlet 42s of the two or more supply members 40.

[0072] <Supply of hot gas> As shown in Figure 2, the manufacturing apparatus 1 may be equipped with one or more supply members 70 (fifth supply member). In the example shown in Figure 2, one supply member 70 is provided, but two or more (for example, two) supply members 70 may be provided. The supply member 70 is a member that supplies hot gas containing oxygen with a temperature of 700°C to 1000°C to the inside of the calcination furnace 10. The temperature of the hot gas supplied from the supply member 70 may be 750°C to 950°C or 800°C to 900°C. The supply member 70 may supply extracted gas from the clinker cooler 6 as the hot gas to the inside of the calcination furnace 10. An inlet is provided at the end of the supply member 70 for discharging (blowing) the hot gas into the inside of the calcination furnace 10. The oxygen concentration of the hot gas (extracted gas) is higher than the oxygen concentration of the exhaust gas from the rotary kiln 4.

[0073] Here, we will explain the relative positions of one or more supply members 70, one or more supply members 30, and one or more supply members 40. In the following, we will focus on one supply member 70, one supply member 30, and one supply member 40 and explain their relative positions, but the same relative positions hold true for all combinations of supply member 70 and supply member 30, and for all combinations of supply member 70 and supply member 40.

[0074] The position where hot gas is supplied by the supply member 70 corresponds to the position of the inlet provided at the end of the supply member 70, and this position may hereafter be referred to as the "supply position of the supply member 70". In the flow direction F, the supply position of the supply member 70 may be the position corresponding to the supply position of the supply member 30, or it may be located between the supply position of the supply member 30 and the supply position of the supply member 40. The position between the supply position of the supply member 30 and the supply position of the supply member 40 corresponds to a position upstream of the supply position of the supply member 40 and downstream of the supply position of the supply member 30. By blowing hot gas from the supply member 70 into the interior of the calcination furnace 10, the combustibility of solids such as pulverized coal can be further improved.

[0075] When the flow direction F is aligned vertically, the height of the supply position of the supply member 70 may be the same as the height of the supply position of the supply member 30. In this case, at least a portion of the inlet of the supply member 70 is at the same height as at least a portion of the inlet 32 ​​of the supply member 30. When the flow direction F is aligned vertically, the height of the supply position of the supply member 70 may be lower than the height of the supply position of the supply member 40 and higher than the height of the supply position of the supply member 30. In this case, the uppermost position of the inlet of the supply member 70 is below the lowermost position of the inlet 42 of the supply member 40, and the lowermost position of the inlet of the supply member 70 is above the uppermost position of the inlet 32 ​​of the supply member 30.

[0076] [Method for producing cement clinker] Next, as an example of a method for manufacturing cement clinker, the clinker manufacturing process performed in manufacturing apparatus 1 will be described. The clinker manufacturing process performed in manufacturing apparatus 1 includes, for example, a preheating step, a calcination step, a firing step, and a cooling step. These steps are performed for at least partially overlapping periods. The preheating step is a process in which the cement raw materials are preheated in cyclones C1 to C4 with high-temperature gas, including exhaust gas from rotary kiln 4.

[0077] The calcination process is the process of calcining the cement raw materials in the calcination furnace 10. In the calcination process, the cement raw materials are calcined by exhaust gas from the rotary kiln 4 and various heat energy sources supplied to the inside of the calcination furnace 10. The firing process is the process of firing the cement raw materials in the rotary kiln 4 using combustion gas from the burner 4b. The cooling process is the process of cooling the clinker produced in the rotary kiln 4 in the clinker cooler 6.

[0078] An example of the calcination process described above will be explained in detail. The calcination process includes, for example, a first supply process, a second supply process, an ammonia supply process, a hot gas supply process, and a heating process. The first supply process, the second supply process, the ammonia supply process, the hot gas supply process, and the heating process are each performed for at least partially overlapping periods.

[0079] The first supply step is a step of supplying a thermal energy source containing solid matter such as pulverized coal to the inside of the calcination furnace 10 using one or more supply members 30. The second supply step is a step of supplying a thermal energy source containing solid matter such as pulverized coal to the inside of the calcination furnace 10 using one or more supply members 40. The ammonia supply step is a step of supplying ammonia to the inside of the calcination furnace 10 using one or more supply members 50.

[0080] The ratio of the calorific value of ammonia supplied to the calcination furnace 10 in the ammonia supply process to the total calorific value of the thermal energy sources supplied to the calcination furnace 10 in the first supply process, the second supply process, and the ammonia supply process (corresponding to the total calorific value already described above) may be 0.01 to 0.90. In the ammonia supply process, ammonia may be supplied to the inside of the calcination furnace 10 together with air having an air ratio of 0.1 to 1.0. The ratio of the calorific value of ammonia supplied to the calcination furnace 10 in the ammonia supply process to the total calorific value may be 0.01 to 0.55, and the ratio of the calorific value of the thermal energy sources containing solids supplied to the calcination furnace 10 in the first supply process and the second supply process may be 0.45 to 0.99.

[0081] The heat gas supply process is a process of supplying oxygen-containing heat gas to the inside of the calcination furnace 10 using one or more supply members 70. The temperature of the heat gas supplied from one or more supply members 70 may be 700°C to 1000°C. The heat gas supplied from one or more supply members 70 may be extracted gas (cooler extracted gas) that has been used to cool the clinker in the clinker cooler 6. The heating process is a process of heating the cement raw materials in the calcination furnace 10 while burning ammonia gas.

[0082] [Second Embodiment] Next, with reference to Figures 4 and 5, a cement clinker manufacturing apparatus and manufacturing method according to the second embodiment will be described.

[0083] The manufacturing apparatus 1 according to the second embodiment differs from the manufacturing apparatus 1 according to the first embodiment in that the thermal energy source supply unit 20 has one or more supply members 50A instead of one or more supply members 50. The one or more supply members 50A (third supply member) may have the same function and configuration as the one or more supply members 50, except for the position in which they are installed. The configuration of the manufacturing apparatus 1 according to the second embodiment will be described below, but matters not described below may have the same configuration and function as the manufacturing apparatus 1 according to the first embodiment.

[0084] In Figures 4 and 5, one supply member 50A is shown, but two or more (for example, two) supply members 50A may be provided. The supply member 50A is a member (burner) that supplies ammonia to the inside of the calcination furnace 10. The supply member 50A is configured to supply ammonia-containing gas containing ammonia.

[0085] The supply member 50A is provided with an inlet 52 at one end for discharging (blowing in) ammonia (ammonia-containing gas) into the calcination furnace 10. The end of the supply member 50A including the inlet 52 functions as a nozzle. The inlet 52 of the supply member 50A may be provided with one or more openings for introducing ammonia. In addition to one or more openings for discharging ammonia, the inlet 52 at the end of the supply member 50A may include one or more openings for discharging combustion air. The end of the supply member 50A that functions as a nozzle may be installed horizontally. The end of the supply member 50A may be connected to the side wall of the calcination furnace 10.

[0086] If two or more supply members 50A are provided, the two or more supply members 50A have similar functions and configurations. In the flow direction F, the inlets 52 of the two or more supply members 50A may be arranged at corresponding positions. If the flow direction F is vertical, the inlets 52 of the two or more supply members 50A may be arranged at corresponding height positions. The two or more supply members 50A may be arranged at different positions in the circumferential direction around the central axis of the calcination furnace 10.

[0087] The supply member 50A may supply ammonia together with combustion air to the inside of the calcination furnace 10. In the supply member 50A, the ammonia and combustion air may be combined before being introduced into the inside of the calcination furnace 10, or they may be supplied separately without being combined. The air ratio of the combustion air supplied together with ammonia from the supply member 50A is, for example, 0.1 to 1.0.

[0088] The air-fuel ratio of the combustion air from the supply member 50A may be 0.15 or higher, 0.2 or higher, or 0.25 or higher, from the viewpoint of promoting ammonia combustion. The air-fuel ratio of the combustion air from the supply member 50A may be 0.9 or lower, 0.8 or lower, or 0.7 or lower, from the viewpoint of efficiently introducing air. The air-fuel ratio of the combustion air from the supply member 50A may be 0.3 to 1.0, or 0.5 to 1.0. In one example, exhaust gas from a chlorine bypass system is introduced as combustion air from the supply member 50A.

[0089] The supply member 50A may continuously supply ammonia-containing gas during the period in which the calcination furnace 10 is operating, or it may supply ammonia-containing gas only for a portion of the period in which the calcination furnace 10 is operating. The "calorific value ratio" defined in the first embodiment is defined in the second embodiment as follows. Heat generation ratio: The ratio of the heat generation of ammonia supplied by one or more supply members 50A to the total heat generation of the thermal energy sources supplied by one or more supply members 30, one or more supply members 40, and one or more supply members 50A.

[0090] The above calorific value ratio may be 0.05 or higher, 0.1 or higher, 0.15 or higher, or 0.20 or higher, from the viewpoint of promoting the effective utilization of ammonia. The above calorific value ratio may be 0.7 or lower, 0.55 or lower, 0.50 or lower, 0.45 or lower, 0.4 or lower, 0.35 or lower, or 0.3 or lower, from the viewpoint of suppressing combustion inhibition of solids caused by ammonia. The above 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 30 and one or more supply members 40 to the total calorific value may be 0.45 to 0.99. The above 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 30 and one or more supply members 40 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.

[0091] Here, we will explain the relative positions of one or more supply members 50A, one or more supply members 30, and one or more supply members 40. In the following, we will focus on one supply member 50A, one supply member 30, and one supply member 40 and explain their relative positions, but the same relative positions hold true for all combinations of supply member 50A and supply member 30, and the same relative positions hold true for all combinations of supply member 50A and supply member 40.

[0092] The supply member 50A is formed separately from the supply member 40. That is, the supply member 50A is physically separated from the supply member 40. The supply member 50A discharges ammonia from a different position than the position where the supply member 40 supplies the thermal energy source. In other words, the position where the supply member 40 supplies pulverized coal to the inside of the calcination furnace 10 and the position where the supply member 50A supplies ammonia-containing gas to the inside of the calcination furnace 10 are different from each other.

[0093] In the flow direction F, the position where the supply member 50A supplies ammonia (third supply position) is located either at the position corresponding to the supply position of the supply member 40, or between the supply position of the supply member 40 and the supply position of the supply member 30. The space between the supply position of the supply member 40 and the supply position of the supply member 30 means a position upstream of the supply position of the supply member 40 and downstream of the supply position of the supply member 30. The position where the supply member 50A supplies ammonia corresponds to the position of the inlet 52 of the supply member 50A, and this position may hereafter be referred to as the "supply position of the supply member 50A".

[0094] When the flow direction F is aligned vertically, the height of the supply position of the supply member 50A may be the same as the height of the supply position of the supply member 40. In this case, at least a portion of the inlet 52 of the supply member 50A is located at the same height as at least a portion of the inlet 42 of the supply member 40. When the flow direction F is aligned vertically, the height of the supply position of the supply member 50A may be lower than the height of the supply position of the supply member 40 and higher than the height of the supply position of the supply member 30. In this case, the uppermost position of the inlet 52 of the supply member 50A is lower than the lowermost position of the inlet 42 of the supply member 40, and the lowermost position of the inlet 52 of the supply member 50A is higher than the uppermost position of the inlet 32 ​​of the supply member 30. In the circumferential direction around the central axis of the calcination furnace 10, the positional relationship between the supply member 50A and the supply member 40 may be set in any way, as long as these members can be installed.

[0095] The supply position of the supply member 50A is set to a position where ammonia is supplied to region R (a region with an ambient temperature of 900°C or higher), similar to the supply position of the supply member 50. When the flow direction F is along the vertical direction, the supply position cross section described above is a horizontal cross section at the same height position as the supply position of the supply member 50A inside the calcination furnace 10. The ambient temperature of region R (the region inside the calcination furnace 10 from which ammonia is supplied from the supply member 50A) may be 910°C or higher, 920°C or higher, or 930°C or higher, and may be 1000°C or lower, 990°C or lower, 980°C or lower, or 970°C or lower.

[0096] In Figures 4 and 5, the position of the supply member 50A in the flow direction F, with the inlet 10a of the calcination furnace 10 as the reference point (0), is indicated by "B". The position of the supply member 50A in the flow direction F is preferably set such that "B / L" satisfies the following conditions: B / L may be 0.15 or more, 0.16 or more, 0.18 or more, 0.19 or more, or 0.20 or more. B / L may be 0.30 or less, 0.28 or less, 0.26 or less, 0.24 or less, or 0.22 or less. In one example, B / L is 0.15 to 0.30, 0.16 to 0.28, or 0.18 to 0.22. The position of the supply member 50A is defined by the center position of the inlet 52 of the supply member 50A. If two or more supply members 50A are provided, the position "B" (the supply position of the supply member 50A) may be calculated using the arithmetic mean of the center positions of the inlet 52 of the two or more supply members 50A.

[0097] In the manufacturing apparatus 1 according to the second embodiment, various processes similar to the clinker manufacturing process described above may be performed. The ammonia supply process includes supplying ammonia to the inside of the calcination furnace 10 by one or more supply members 50A.

[0098] The ratio of the calorific value of ammonia supplied to the calcination furnace 10 in the ammonia supply process to the total calorific value of the thermal energy sources supplied to the calcination furnace 10 in the first supply process, the second supply process, and the ammonia supply process including the supply of ammonia by the supply member 50A (corresponding to the total calorific value as defined again in the second embodiment) may be 0.01 to 0.90. In the ammonia supply process including the supply of ammonia by the supply member 50A, ammonia may be supplied to the inside of the calcination furnace 10 together with air having an air ratio of 0.1 to 1.0. The ratio of the calorific value of ammonia supplied to the calcination furnace 10 in the ammonia supply process including the supply of ammonia by the supply member 50A to the total calorific value may be 0.01 to 0.55, and the ratio of the calorific value of the thermal energy sources including solids supplied to the calcination furnace 10 in the first supply process and the second supply process may be 0.45 to 0.99.

[0099] [Summary of the First and Second Embodiments] The thermal energy source supply unit 20 illustrated above has an ammonia supply unit that either supplies ammonia to the inside of the calcination furnace 10 by one or more supply members 50, or supplies ammonia to the inside of the calcination furnace 10 by one or more supply members 50A. For the sake of explanation, the ammonia supply unit of the thermal energy source supply unit 20 will be referred to as the "ammonia supply unit 22" (see also Figure 1). When the ammonia supply unit 22 supplies ammonia by one or more supply members 50, it does not have a supply member 50A. When the ammonia supply unit 22 supplies ammonia by one or more supply members 50A, it does not have a supply member 50.

[0100] The ammonia supply process described above is performed by the ammonia supply unit 22. That is, the ammonia supply process is a process that includes either supplying ammonia to the inside of the calcination furnace 10 by one or more supply members 50, or supplying ammonia to the inside of the calcination furnace 10 by one or more supply members 50A. In the ammonia supply process, if ammonia is supplied by one or more supply members 50, one or more supply members 50A are not provided in the first place, so ammonia is not supplied from one or more supply members 50A. In the ammonia supply process, if ammonia is supplied by one or more supply members 50A, one or more supply members 50 are not provided in the first place, so ammonia is not supplied from one or more supply members 50.

[0101] Regardless of whether the ammonia supply unit 22 supplies ammonia from supply member 50 or supply member 50A, the calcination furnace 10 may be a direct-type calcination furnace. The types of calcination furnaces will be described with reference to Figures 6, 7(a), and 7(b). Calcination furnaces installed in cement clinker manufacturing equipment are broadly classified into two types: direct-type calcination furnaces and separated-type calcination furnaces.

[0102] As shown in Figure 6, a direct calcination furnace refers to a calcination furnace formed to allow a fluid of a specific shape to flow out. High-temperature kiln exhaust gas is directly introduced from the inlet (e.g., the bottom) of the calcination furnace, and raw materials mainly composed of limestone, which are introduced from a part opposite the inlet (e.g., the top), are heated to carry out the decarboxylation reaction of limestone. In a direct calcination furnace, the raw materials are heated by high-temperature gas containing kiln exhaust gas. Calcination furnace 110A shown in Figure 7(a) and calcination furnace 110B shown in Figure 7(b) are separate calcination furnaces.

[0103] Calcinerator 110A is a fluidized bed calcinerator classified as a separate-type calcinerator. As shown in Figure 7(a), a fluidized bed calcinerator is a type of combustion furnace in which air is uniformly supplied from the bottom of the fluidized medium (raw material) filled in the furnace to form a fluidized bed. In a fluidized bed calcinerator, limestone and pulverized coal are introduced into the fluidized bed, and the decarboxylation reaction of limestone takes place.

[0104] The calcination furnace 110B is an airflow / vortex type calcination furnace classified as a separate-type calcination furnace. In an airflow / vortex type calcination furnace, as shown in Figure 7(b), raw materials mainly composed of limestone and high-temperature cooler extraction gas are fed into the furnace, and the decarboxylation reaction of limestone is carried out by the combustion of pulverized coal supplied into the furnace. The raw materials after the decarboxylation reaction are carried along with the kiln exhaust gas and introduced to downstream equipment through a duct. In an airflow / vortex type calcination furnace, the kiln exhaust gas is not directly introduced into the furnace (the part where the raw materials are calcined).

[0105] The first embodiment and the second embodiment may differ in aspects other than the supply member 50 and the supply member 50A. As described above, various examples have been explained in each of the first and second embodiments, but at least some of the matters explained in the other examples may be combined in any one of the examples described above.

[0106] [Verification results from simulation] Next, we will explain the results of a simulation to verify the effects of supplying ammonia to the inside of the calcination furnace 10. The simulation was performed using "R-FLOW," a thermal fluid and powder analysis software manufactured by R-FLOW Co., Ltd. In the simulation, the calcination furnace 10 had two burners for pulverized coal placed in the lower section and two burners for pulverized coal placed in the upper section. Hereinafter, the two burners for pulverized coal placed in the lower section will be referred to as "lower burner 1" and "lower burner 2," and the two burners for pulverized coal placed in the upper section will be referred to as "upper burner 1" and "upper burner 2." Lower burner 1 and lower burner 2 each correspond to the supply member 30, and upper burner 1 and upper burner 2 each correspond to the supply member 40. It was assumed that only pulverized coal was supplied as solid matter, without any waste. Assuming that 100% pure ammonia is supplied from a burner separate from the upper burners 1 and 2 and the lower burners 1 and 2, and assuming the lower heating value of ammonia (anhydrous basis, 100% purity) is 4,427 kcal / kg, i.e., 1.86 × 10⁻⁶ 7 The value was expressed as J / kg.

[0107] Table 1 below shows the industrial analysis values ​​(mass%: air-dry basis), chemical analysis values ​​(mass%: air-dry basis), and chemical analysis values ​​(mass%: anhydrous, ash-free basis) for the pulverized coal components assumed in the simulation. Furthermore, the lower heating value (arrival basis) of the pulverized coal is assumed to be 5,749 kcal / kg, i.e., 2.415 × 10⁻⁶. 7 The value was expressed as J / kg. [Table 1]

[0108] The particle size distribution of pulverized coal assumed in the simulation is shown in Table 2 below. [Table 2]

[0109] In Table 2 above, the cumulative mass percentage for particle size 8.00 μm (11.00 mass%) represents the ratio of the mass of particles smaller than 8.00 μm to the total mass of pulverized coal. The mass percentage for particle size 8.00 μm (6.00 mass%) represents 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 the columns for particle sizes other than 8.00 μm.

[0110] (Example 1) A simulation was conducted for supplying ammonia from lower burners 3 and 4, which are positioned in the flow direction F corresponding to lower burners 1 and 2. Each of the lower burners 3 and 4 corresponds to a supply member 50 provided in the manufacturing apparatus 1 according to the first embodiment. The general conditions of the simulation are shown below. • Upper burners 1 and 2: The supply rate of pulverized coal from each burner was set to 1 ton / hour. In each of the upper burners 1 and 2, pulverized coal is transported by transport air, and the flow rate of the transport air is set to 500 Nm³. 3 The oxygen concentration was set to 18% at a rate of / h. In each of the upper burners 1 and 2, combustion air is supplied separately from (pulverized coal + conveying air), and the flow rate of this combustion air is set to 1,200 Nm³. 3 The oxygen concentration was set to 18% at a rate of / h. Lower burners 1 and 2: The supply rate of pulverized coal from each burner was set to 1 ton / hour. In each of the lower burners 1 and 2, combustion air is supplied separately from the pulverized coal, and the flow rate of this combustion air is set to 1,200 Nm³. 3 The oxygen concentration was set to 21% at / h. In each of the lower burners 1 and 2, pulverized coal is transported by transport air, and the flow rate of the transport air is set to 500 Nm³. 3 The oxygen concentration was set to 21% at / h. Lower burners 3 and 4: The amount of ammonia supplied from each burner is 1,100 Nm³. 3 I set it to / h. ·In each of the lower-stage burners 3 and 4, combustion air is supplied separately from ammonia, and the flow rate of the combustion air is set to 3,900 Nm 3 / h, and the oxygen concentration is set to 21%. ·The temperature of the cooler extracted gas is set to 919°C. ·The flow rate of the ascending flow introduced from the inlet 10a of the calciner 10 is set to 40,000 Nm 3 / h, and the oxygen concentration of the ascending flow is set to 4%.

[0111] The upper-stage burners 1 and 2 for supplying pulverized coal may be provided at a position where the atmospheric temperature inside the calciner 10 (the temperature measured in a cross section perpendicular to the flow direction F) is about 1000°C in the flow direction F. In this simulation, the positions of the upper-stage burners 1 and 2 are set to a position 0.20 times the total length (L) of the calciner 10. The lower-stage burners 1 and 2 for supplying pulverized coal may be provided at a position where the atmospheric temperature inside the calciner 10 (the temperature measured in a cross section perpendicular to the flow direction F) is about 936°C. In this simulation, the positions of the lower-stage burners 1 and 2 are set to a position 0.10 times the total length (L) of the calciner 10. The lower-stage burners 3 and 4 for supplying ammonia are set to the same positions as the lower-stage burners 1 and 2 in the flow direction F. In the simulation, since the atmospheric temperature inside the calciner 10 is an important factor, it is assumed that in the circumferential direction around the central axis of the calciner 10, the burners may be offset at any angle relative to the upper-stage burners 1 and 2 and the lower-stage burners 1 and 2 that supply pulverized coal.

[0112] Under the simulation conditions according to Example 1, the heat quantity ratio of pulverized coal from each of the upper-stage burners 1 and 2 and the lower-stage burners 1 and 2 is 19%, and the heat quantity ratio of ammonia from each of the lower-stage burners 3 and 4 is 12%. In other words, the ratio of the heat quantity of ammonia supplied from the lower-stage burners 3 and 4 to the total calorific value of the thermal energy sources supplied from all six burners (corresponding to the aforementioned calorific value ratio) is 0.24.

[0113] Under the above conditions according to Example 1, ammonia 1100 Nm 3The theoretical combustion oxygen per hour is, from equation (1) above, 1100 × 3 / 4 = 825 Nm³. 3 The value is / h. The amount of oxygen near the lower burner 3 is calculated from the combustion air supply rate and oxygen concentration as follows: 3900 × 0.21 = 819 Nm³ 3 The ratio is / h. The air-to-air ratio of the combustion air from the lower burner 3 is 819 / 825 (approximately 1.0). In addition to the oxygen from the combustion air, the oxygen near the lower burner 3 is supplied from half (one side) of the upward flow in the calcination furnace 10, which is 40000 / 2 × 0.04 = 800 Nm 3 With the addition of oxygen at / h, the total is 1,619 Nm³. 3 The oxygen level becomes / h, exceeding the theoretical combustion oxygen level. Due to the oxygen exceeding the theoretical combustion oxygen level, the ammonia from lower burner 3 will, in theory, undergo complete combustion. There is no ammonia near upper burners 1 and 2 that would preferentially consume oxygen.

[0114] Figure 8 shows the concentration source distribution of ammonia (NH3) generated inside the calcination furnace 10, obtained by the simulation according to Example 1. The contour plot shown in Figure 8 is the simulation result of the NH3 concentration source distribution inside the calcination furnace 10. The intensity of the color in the contour plot represents the amount of NH3 generated and lost per unit time and unit volume. The lower end of the contour plot corresponds to the inlet 10a of the calcination furnace 10, and the upper end of the contour plot corresponds to the outlet 10b of the calcination furnace 10. From the results according to Example 1 shown in Figure 8, it can be seen that when ammonia is supplied from the lower stage, where the decarboxylation reaction of the limestone raw material has not yet been sufficiently carried out and the ambient temperature is in the high region of 936°C, the combustion rate of ammonia is faster than that of pulverized coal combustion, the ammonia disappears immediately after being supplied from the lower burner, and the ammonia burns sufficiently.

[0115] (Example 2) The simulation was performed under the same conditions as in Example 1, except that the air-to-combustion ratio of the combustion air from each of the lower burners 3 and 4 was 0.72, and the ambient temperature inside the furnace at the ammonia supply position from the lower burners 3 and 4 was 948°C. From the results for Example 2 shown in Figure 8, it can be seen that, similar to Example 1, the decarboxylation reaction of the limestone raw material has not yet been fully carried out, and when ammonia is supplied to a region with a high ambient temperature of 948°C, the ammonia burns sufficiently.

[0116] (Example 3) A simulation was conducted in which ammonia is supplied from upper burners 3 and 4, which are positioned in the flow direction F corresponding to the upper burners 1 and 2, instead of the lower burners 3 and 4. Each of the upper burners 3 and 4 corresponds to a supply member 50A provided in the manufacturing apparatus 1 according to the second embodiment. The simulation conditions were set to the same conditions as in Example 1, except that ammonia is supplied from each of the upper burners 3 and 4 along with air with an air ratio of approximately 1.0, and the ambient temperature inside the furnace at the ammonia supply position from the upper burners 3 and 4 is 900°C.

[0117] The results for Example 3 shown in Figure 8 indicate that the decarboxylation reaction of the limestone raw material has not yet been fully carried out, and that when ammonia is supplied to a high ambient temperature of 900°C, ammonia burns to some extent, although it is inferior to Example 1 at 936°C.

[0118] (Example 4) The simulation was performed under the same conditions as in Example 3, except that the air-to-air ratio of the combustion air from each of the upper burners 3 and 4 was 0.72, and the ambient temperature inside the furnace at the ammonia supply position from the upper burners 3 and 4 was 912°C. From the results for Example 4 shown in Figure 8, it can be seen that the decarboxylation reaction of the limestone raw material has not yet been fully carried out, and when ammonia is supplied to a high ambient temperature region of 912°C, ammonia burns to some extent, although it is inferior to Example 2 at 948°C.

[0119] (Example 5) Based on the temperature fluctuation range in the actual machine, the temperature of the cooler extraction gas was reduced to 800°C, and the simulation was performed under the same conditions as in Example 2, except that the ambient temperature inside the furnace at the ammonia supply position from the lower burners 3 and 4 was 965°C. From the results for Example 5 shown in Figure 8, it can be seen that the decarboxylation reaction of the limestone raw material has not yet been fully carried out, and when ammonia is supplied to a region with a high ambient temperature of 965°C, the ammonia burns sufficiently.

[0120] (Comparative example) Similar to Examples 3 and 4, simulations were performed under the same conditions as Example 5, except that the ambient temperature inside the furnace at the supply location of the upper burners 3 and 4 was 870°C, while pulverized coal was supplied from the upper burners 1 and 2 and the lower burners 1 and 2, and ammonia was supplied from the upper burners 3 and 4. The results of the comparative example shown in Figure 8 appear similar to those of Examples 3 and 4, but the highest ammonia concentration was obtained at the outlet of the calcination furnace, which will be described later. Furthermore, it can be seen that the decarboxylation reaction of the limestone raw material has not yet been fully carried out, and when ammonia is supplied in a region with a low ambient temperature of 870°C, it is difficult for the ammonia to burn.

[0121] (Temperature distribution in the flow direction in a calcination furnace) In each simulation for Example 1, Example 2, Example 3, Example 4, Example 5, and Comparative Example 1, the ambient temperature was calculated for each height position of the calcination furnace 10 (by changing the height position). The results calculated by the simulation are shown in Figure 9. In the graph of Figure 9, the horizontal axis represents the value obtained by dividing the height [m] from the bottom (furnace bottom) of the calcination furnace 10 by the total length [m] of the calcination furnace 10 in the vertical direction, and the vertical axis represents the average gas temperature [°C] in a cross-section perpendicular to the vertical direction.

[0122] Table 3 shows the results obtained from the graphs in Figure 9, where the calculated values ​​for Examples 1, 2, and 5 were read at the height near the lower burners 3 and 4 (horizontal axis value around 0.0097), and for Examples 3, 4, and the comparative example, the calculated values ​​were read at the height near the upper burners 3 and 4 (horizontal axis value around 0.178). Table 3 also includes the results of calculating the ammonia concentration in the duct from the outlet 10b of the calcination furnace 10 to the cyclone C4 as the "outlet NH3 concentration".

[0123] [Table 3]

[0124] (Summary of key conditions) The main conditions (air ratio, type of thermal energy source, and percentage of heat output) in Examples 1-5 and the Comparative Example are shown in Table 4 below. In Table 4, the numbers in parentheses represent the percentage of heat output from each thermal energy source relative to the total heat output from the six burners.

[0125] [Table 4]

[0126] (Ammonia combustion characteristics considering chemical reactions) Inside the calcination furnace 10, the chemical reactions of the raw materials, pulverized coal, and gas are thought to proceed according to the following equation. <Raw materials>

number

[0127] <Finely pulverized coal>

number

[0128] <Gas>

number

[0129] For ammonia to burn efficiently, the chemical reactions shown in equations (C6) and (C7) above must proceed. On the other hand, inside the calcination furnace 10, when CO and NH2 (radicals) from the combustion of pulverized coal coexist, OH (radicals) react with NH2 more than CO, resulting in residual CO. Therefore, in the co-firing of pulverized coal and ammonia (NH3), it is important to burn the ammonia as quickly as possible in the furnace and prevent it from coexisting with CO. For stable combustion of ammonia, not only is a high oxygen concentration required in the region where the ammonia is supplied, but a high ambient temperature is also necessary; supplying it to an atmosphere of 900°C or higher is sufficient. However, in the calcination furnace 10, the temperature inside the furnace is mostly below 900°C due to the decarboxylation reaction of the limestone raw material. For example, in the jet-bed type calcination furnaces (direct calcination furnaces) of Examples 1 to 5 described above, kiln exhaust gas is supplied from the bottom of the calcination furnace 10 at approximately 1100°C, so ammonia can be rapidly burned by supplying it to the lower part of the calcination furnace. The simulation results described above show that in Examples 1-5, the location (region) where ammonia was supplied was a sufficiently high-temperature environment, resulting in better ammonia combustion compared to the comparative example. Furthermore, in Examples 1, 2, and 5, the ambient temperature was particularly high at 936°C or higher, which likely contributed to better ammonia combustion compared to Examples 3 and 4. Comparing Examples 1 and 2, and Examples 3 and 4, which had different air ratios, no significant differences were observed. The difference in air ratios (approximately 0.72 and 1.0) suggests that ambient temperature has a greater influence. In the comparative example, the ambient temperature was low at 870°C, which likely resulted in less efficient ammonia combustion compared to Examples 1-5.

[0130] (Summary of this disclosure) The cement clinker manufacturing method described above includes: a first supply step of supplying a thermal energy source containing solids to the inside of a calcination furnace (10) that calcines cement raw materials before heating by a rotary kiln (4) that produces cement clinker, using one or more first supply members (30); a second supply step of supplying a thermal energy source containing solids to the inside of the calcination furnace (10) using one or more second supply members (40); and an ammonia supply step of supplying ammonia to the inside of the calcination furnace (10) using one or more third supply members (50A), or supplying ammonia to the inside of the calcination furnace (10) using one or more fourth supply members (50). Based on the gas flow (F) inside the calcination furnace (10), the first supply position where one or more first supply members (30) supply a thermal energy source containing solids is located upstream of the second supply position where one or more second supply members (40) supply a thermal energy source containing solids. Based on the gas flow (F) inside the calcination furnace (10), the third supply position where one or more third supply members (50A) supply ammonia is located at a position corresponding to the second supply position, or between the second supply position and the first supply position, and the third supply position is set to supply ammonia to a region (R) where the ambient temperature is 900°C or higher. Based on the gas flow (F) inside the calcination furnace (10), the fourth supply position where one or more third supply members (50) supply ammonia is located at a position corresponding to the first supply position, or upstream of the first supply position, and the fourth supply position is set to supply ammonia to a region (R) where the ambient temperature is 900°C or higher.

[0131] As discussed in the simulation results above, inside the calcination furnace (10), when CO and NH2 (radicals) from the combustion of solids such as pulverized coal coexist, OH (radicals) react with NH2 more than CO, resulting in residual CO. Therefore, when burning ammonia together with solids, it is important to burn the ammonia quickly inside the calcination furnace (10) to prevent it from coexisting with CO. In the above manufacturing method, ammonia is supplied from either the third supply member (50A) or the fourth supply member (50) to the region (R) where the ambient temperature is 900°C or higher. This allows the ammonia to burn quickly inside the calcination furnace (10). The above simulation also confirmed that supplying ammonia to the region (R) where the ambient temperature is 900°C or higher leads to faster combustion of that ammonia. Thus, the above manufacturing method is useful for suppressing the generation of CO (carbon monoxide) when supplying ammonia into the calcination furnace (10).

[0132] In the manufacturing method described above, the ratio of the calorific value of ammonia supplied to the calcination furnace (10) in the ammonia supply process to the total calorific value of the thermal energy sources supplied to the calcination furnace (10) in the first supply process, the second supply process, and the ammonia supply process may be 0.01 to 0.90.

[0133] In this case, it is useful for achieving both the efficient use of ammonia and the suppression of combustion inhibition of solids caused by the supply of ammonia.

[0134] In the manufacturing method described above, the ratio of the calorific value of ammonia supplied to the calcination furnace (10) in the ammonia supply step to the total calorific value may be 0.01 to 0.55, and the ratio of the calorific value of the thermal energy source containing solids supplied to the calcination furnace (10) in the first supply step and the second supply step to the total calorific value may be 0.45 to 0.99.

[0135] In this case, it is even more useful in achieving both the effective utilization of ammonia and the suppression of combustion inhibition of solids caused by the supply of ammonia. Furthermore, verification by the simulation described above confirmed that CO generation is suppressed by supplying various thermal energy sources, including ammonia, at least in this proportion of calorific value.

[0136] In the manufacturing method described above, in the ammonia supply step, ammonia may be supplied to the inside of the calcination furnace (10) together with air having an air ratio of 0.1 to 1.0.

[0137] In this case, the ammonia can be eliminated more reliably immediately after its supply. This is useful in suppressing the generation of CO due to the incomplete combustion of solids caused by the introduction of ammonia.

[0138] In the manufacturing method described above, the solids supplied in the first and second supply processes may be pulverized coal. The industrial analysis values ​​of the pulverized coal on an air-dry basis may be 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 chemical analysis values ​​of the pulverized coal on an air-dry basis may be 60-75% by mass for carbon (C), 3-5% by mass for hydrogen (H), 6-9% by mass for oxygen (O), 1-3% by mass for nitrogen (N), and 0.1-1.0% by mass for sulfur (S). The calorific value of the pulverized coal may be 4500-6500 kcal / kg.

[0139] The simulation verification described above confirmed that CO generation is suppressed when pulverized coal having such components and calorific value is supplied as a solid component from the first supply member (30) and the second supply member (40).

[0140] In the manufacturing method described above, the solid content supplied in the first and second supply steps may be pulverized coal. The particle size distribution of the pulverized coal may be such that 5 to 20% by mass consists of particles with a particle size of 8.00 μm or more and less than 16.00 μm, 20 to 40% by mass consists of particles with a particle size of 16.00 μm or more and less than 32.00 μm, 20 to 40% by mass consists of particles with a particle size of 32.00 μm or more and less than 64.00 μm, and 10 to 30% by mass consists of particles with a particle size of 64.00 μm or more and less than 128.00 μm.

[0141] The simulation verification described above confirmed that CO generation is suppressed when pulverized coal having such a particle size distribution is supplied as solid material from the first supply member (30) and the second supply member (40).

[0142] The manufacturing method described above may further include a hot gas supply step in which one or more fifth supply members (70) supply hot gas containing oxygen to the inside of the calcination furnace (10). The temperature of the hot gas may be 700°C to 1000°C. Based on the gas flow (F) inside the calcination furnace (10), the position in which one or more fifth supply members (70) supply the hot gas may correspond to the second supply position, or may be located between the second supply position and the first supply position.

[0143] The supply of ammonia reduces oxygen levels, which may lead to a shortage of oxygen for burning the solids. In the above method, by supplying oxygen-containing hot gas into the calcination furnace (10), the combustion of the solids can be promoted, and the amount of unburned solids generated can be reduced. Therefore, even when ammonia is introduced, this method is useful in suppressing the generation of CO due to incomplete combustion of solids.

[0144] In the manufacturing method described above, in the heat gas supply step, the extracted gas (cooler extracted gas) from the clinker cooler (6) that cools the cement clinker produced in the rotary kiln (4) may be supplied as the heat gas.

[0145] In this case, the gas used to cool the clinker can be effectively utilized as a hot gas to promote the combustion of the solid components.

[0146] In the manufacturing method described above, the calcination furnace (10) may be a direct calcination furnace in which exhaust gas from the rotary kiln (4) is directly introduced.

[0147] The exhaust gas temperature from the rotary kiln (4) is approximately 1100°C, and in a direct-type calcination furnace, this exhaust gas is also used to heat the cement raw materials. In such a direct-type calcination furnace, there is a region where the ambient temperature is above 900°C to some extent, which reduces the constraints on the location of ammonia supply compared to other types.

[0148] The cement clinker manufacturing apparatus (1) described above comprises a rotary kiln (4) that heats cement raw materials to produce cement clinker, a calcination furnace (10) that calcines the cement raw materials before heating by the rotary kiln (4), one or more first supply members (30) that supply a thermal energy source containing solids to the inside of the calcination furnace (10), one or more second supply members (40) that supply a thermal energy source containing solids to the inside of the calcination furnace (10), and an ammonia supply unit (22) that either supplies ammonia to the inside of the calcination furnace (10) by one or more third supply members (50A), or supplies ammonia to the inside of the calcination furnace (10) by one or more fourth supply members (50). Based on the gas flow (F) inside the calcination furnace (10), the first supply position where one or more first supply members (30) supply a thermal energy source containing solids is located upstream of the second supply position where one or more second supply members (40) supply a thermal energy source containing solids. Based on the gas flow (F) inside the calcination furnace (10), the third supply position where one or more third supply members (50A) supply ammonia is located at a position corresponding to the second supply position, or between the second supply position and the first supply position, and the third supply position is set to a position where ammonia is supplied to a region (R) where the ambient temperature is 900°C or higher. Based on the gas flow (F) inside the calcination furnace (10), the fourth supply position where one or more third supply members (50) supply ammonia is located at a position corresponding to the first supply position, or upstream of the first supply position, and the fourth supply position is set to a position where ammonia is supplied to a region (R) where the ambient temperature is 900°C or higher.

[0149] In this manufacturing apparatus (1), the same process as the manufacturing method described above is carried out. Therefore, the manufacturing apparatus (1), like the manufacturing method described above, is useful in suppressing the generation of CO (carbon monoxide) when supplying ammonia into the calcination furnace (10). [Explanation of Symbols]

[0150] 1...Manufacturing equipment (cement clinker manufacturing equipment), 4...Rotary kiln, 6...Clinker cooler, 10...Calibration furnace, 20...Heat energy source supply unit, 22...Ammonia supply unit, 30...Supply member (first supply member), 40...Supply member (second supply member), 50...Supply member (fourth supply member), 50A...Supply member (third supply member), 70...Supply member (fifth supply member), F...Flow direction.

Claims

1. A first supply step involves supplying a thermal energy source containing solids to the inside of a calcination furnace, which calcines cement raw materials before heating them in a rotary kiln to produce cement clinker, using one or more first supply members. A second supply step involves supplying a thermal energy source containing solid matter to the inside of the calcination furnace by one or more second supply members, The process includes an ammonia supply step which involves supplying ammonia to the inside of the calcination furnace by one or more third supply members, or supplying ammonia to the inside of the calcination furnace by one or more fourth supply members, Based on the gas flow inside the calcination furnace, the first supply position where one or more first supply members supply a thermal energy source containing solid matter is located upstream of the second supply position where one or more second supply members supply a thermal energy source containing solid matter. Based on the gas flow inside the calcination furnace, the third supply position where the one or more third supply members supply ammonia is located at a position corresponding to the second supply position, or between the second supply position and the first supply position, and the third supply position is set to a position where ammonia is supplied to a region where the ambient temperature is 900°C or higher. Based on the gas flow inside the calcination furnace, the fourth supply position where the one or more fourth supply members supply ammonia is located at a position corresponding to the first supply position, or upstream of the first supply position, and the fourth supply position is set to a position where ammonia is supplied to a region where the ambient temperature is 900°C or higher. A method for manufacturing cement clinker.

2. The ratio of the calorific value of ammonia supplied to the calcination furnace in the ammonia supply process to the total calorific value of the thermal energy sources supplied to the calcination furnace in the first supply process, the second supply process, and the ammonia supply process is 0.01 to 0.

90. A method for producing cement clinker according to claim 1.

3. The ratio of the calorific value of ammonia supplied to the calcination furnace in the ammonia supply process to the total calorific value is 0.01 to 0.

55. The ratio of the heat energy source containing solids supplied to the calcination furnace in the first and second supply steps to the total heat energy is 0.45 to 0.

99. A method for producing cement clinker according to claim 2.

4. In the ammonia supply step, ammonia is supplied to the inside of the calcination furnace together with air having an air-to-air ratio of 0.1 to 1.

0. A method for producing cement clinker according to any one of claims 1 to 3.

5. The solid content supplied in the first and second supply steps is pulverized coal. The industrial analysis values ​​of the aforementioned pulverized coal on an air-dry basis are as follows: volatile matter is 25-35% by mass, moisture is 2-4% by mass, fixed carbon is 40-60% by mass, and ash is 10-25% by mass. The chemical analysis values ​​of the aforementioned pulverized coal on an air-dry basis are as follows: 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. The calorific value of the pulverized coal is 4500 to 6500 kcal / kg. A method for producing cement clinker according to any one of claims 1 to 3.

6. The solid content supplied in the first and second supply steps is pulverized coal. The particle size distribution of the aforementioned pulverized coal is, Particles having a particle size of 8.00 μm or larger and less than 16.00 μm make up 5 to 20% by mass. Particles having a particle size of 16.00 μm or larger and less than 32.00 μm make up 20 to 40% by mass. Particles having a particle size of 32.00 μm or larger and less than 64.00 μm make up 20 to 40% by mass. Particles having a particle size of 64.00 μm or larger and less than 128.00 μm make up 10 to 30% by mass. A method for producing cement clinker according to any one of claims 1 to 3.

7. The process further includes a heat gas supply step of supplying a hot gas containing oxygen to the inside of the calcination furnace by one or more fifth supply members, The temperature of the hot gas is between 700°C and 1000°C. Based on the gas flow inside the calcination furnace, the position where the one or more fifth supply members supply the hot gas is either a position corresponding to the second supply position, or positioned between the second supply position and the first supply position. A method for producing cement clinker according to any one of claims 1 to 3.

8. In the aforementioned heat gas supply process, extracted gas from a clinker cooler that cools the cement clinker produced in the rotary kiln is supplied as the heat gas. A method for producing cement clinker according to claim 7.

9. The calcination furnace is a direct-type calcination furnace in which exhaust gas from the rotary kiln is directly introduced. A method for producing cement clinker according to any one of claims 1 to 3.

10. A rotary kiln that heats cement raw materials to produce cement clinker, Before heating by the rotary kiln, a calcination furnace is used to calcine the cement raw materials, One or more first supply members supply a thermal energy source containing solids to the inside of the calcination furnace, One or more second supply members supply a thermal energy source containing solids to the inside of the calcination furnace, The system includes an ammonia supply unit that either supplies ammonia to the inside of the calcination furnace by one or more third supply members, or supplies ammonia to the inside of the calcination furnace by one or more fourth supply members, Based on the gas flow inside the calcination furnace, the first supply position where one or more first supply members supply a thermal energy source containing solid matter is located upstream of the second supply position where one or more second supply members supply a thermal energy source containing solid matter. Based on the gas flow inside the calcination furnace, the third supply position where the one or more third supply members supply ammonia is located at a position corresponding to the second supply position, or between the second supply position and the first supply position, and the third supply position is set to a position where ammonia is supplied to a region where the ambient temperature is 900°C or higher. Based on the gas flow inside the calcination furnace, the fourth supply position where the one or more fourth supply members supply ammonia is located at a position corresponding to the first supply position, or upstream of the first supply position, and the fourth supply position is set to a position where ammonia is supplied to a region where the ambient temperature is 900°C or higher. A manufacturing apparatus for cement clinker.

Images