Cement clinker manufacturing system

Abstract

The present invention provides a cement clinker manufacturing system that allows for easier control of the combustion environment of a calcination furnace when the exhaust gas from the calcination furnace is circulated, compared to conventional systems. [Solution] This system comprises a calcinerator that calcines cement raw materials using a combustion-supporting gas, a solid-gas separator that separates the cement raw materials and calcinerator exhaust gas discharged from the calcinerator into solid and gas components, a heat exchanger that performs heat exchange between the calcinerator exhaust gas separated by the solid-gas separator and a first gas containing oxygen, a cooling device that further cools the calcinerator exhaust gas, whose temperature has decreased after passing through the heat exchanger, using a cooling medium different from the first gas, a first pipe that guides the first gas, which is a mixture of the calcinerator exhaust gas that has passed through the cooling device and a second gas with a higher oxygen concentration than air, to the heat exchanger, and a second pipe that guides the first gas, whose temperature has risen after passing through the heat exchanger, to the calcinerator as a combustion-supporting gas.

Description

Technical Field

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[0001] The present invention relates to a cement clinker production system.

Background Art

[0007] In a calcination furnace, the temperature and gas composition inside the furnace are adjusted to properly decarbonate the supplied cement raw materials. In the system disclosed in Patent Document 1, if the flow rate of calcination furnace exhaust gas or the flow rate of combustion-supporting gas introduced into the heat exchanger fluctuates, the temperature of the calcination furnace exhaust gas that has passed through the heat exchanger fluctuates.

[0008] Fluctuations in the temperature of the incinerator exhaust gas could cause it to exceed the heat resistance temperature of the blower. Furthermore, at the time of introduction into the dust collector, the temperature of the incinerator exhaust gas could exceed the heat resistance temperature of the dust collector. Conversely, fluctuations in the temperature of the incinerator exhaust gas could cause it to drop too low, preventing the combustion-supporting gas from adequately heating up after passing through the heat exchanger.

[0009] For these reasons, in the case of the system disclosed in Patent Document 1, it is necessary to adjust the combustion environment of the calcinerator while monitoring the temperature of the calcinerator exhaust gas cooled by passing through the heat exchanger, the temperature of the combustion-supporting gas heated by passing through the heat exchanger, and the gas composition of the combustion-supporting gas. More specifically, it is necessary to simultaneously control multiple control factors such as the output of the blower for adjusting the flow rate of the circulating calcinerator exhaust gas, the flow rate of the combustion-supporting gas, and the amount of fuel fed into the calcinerator, which necessitates extremely complex control.

[0010] In view of the above problems, the present invention aims to provide a cement clinker manufacturing system that allows for adjustment of the combustion environment of a calcination furnace with simpler control than conventional systems when the exhaust gas of the calcination furnace is circulated. [Means for solving the problem]

[0011] The cement clinker manufacturing system according to the present invention uses a combustion-supporting gas introduced to calcine preheated cement raw materials in a calcination furnace, A solid-gas separation device for separating the cement raw materials and furnace exhaust gas discharged from the furnace, A first heat exchanger performs heat exchange between the furnace exhaust gas separated by the solid-gas separator and a first gas containing oxygen at a lower temperature than the furnace exhaust gas. A cooling device that further cools the exhaust gas from the incinerator, whose temperature has decreased after passing through the first heat exchanger, using a cooling medium different from the first gas, A first pipe leads the first gas, which is a mixture of the exhaust gas from the furnace that has passed through the cooling device and a second gas with a higher oxygen concentration than air, to the first heat exchanger. The invention is characterized by comprising a second pipe that guides the first gas, whose temperature has risen after passing through the first heat exchanger, to the furnace as the combustion-supporting gas.

[0012] According to the above configuration, the first gas, which has undergone heat exchange with the high-temperature furnace exhaust gas by the first heat exchanger, is introduced into the furnace as a combustion-supporting gas. Meanwhile, the high-temperature furnace exhaust gas is cooled by passing through the first heat exchanger and then further cooled by passing through a cooling device. This cooling device cools the furnace exhaust gas using a different cooling medium than that used for the first gas.

[0013] With the above configuration, the temperature of the furnace exhaust gas can be controlled by adjusting the cooling capacity of the cooling device. Here, as mentioned above, the cooling device uses a different cooling medium than the first gas. In other words, adjusting the cooling capacity of the cooling device does not affect the temperature of the first gas.

[0014] Furthermore, with the above configuration, the temperature of the combustion-supporting gas introduced into the calcination furnace can be controlled by adjusting the capacity of the first heat exchanger. For example, if it is desired to increase the temperature of the combustion-supporting gas introduced into the calcination furnace, the amount of fuel introduced into the calcination furnace can be increased to raise the temperature of the calcination furnace exhaust gas discharged from the calcination furnace. In this case, since the temperature of the calcination furnace exhaust gas increases, the temperature of the calcination furnace exhaust gas after passing through the first heat exchanger also increases. However, as mentioned above, this calcination furnace exhaust gas is then cooled by passing through a cooling device. Therefore, by adjusting the cooling capacity of the cooling device, it is possible to lower the temperature of the calcination furnace exhaust gas to a desired temperature, or more specifically, to below the heat resistance temperature of the blower and dust collector. In other words, even if the temperature of the high-temperature calcination furnace exhaust gas introduced into the first heat exchanger is adjusted, it is possible to suppress the impact on the temperature of the calcination furnace exhaust gas downstream.

[0015] In other words, with the above configuration, it becomes possible to independently control the temperature of the combustion-supporting gas introduced into the calcination furnace and the temperature of the calcination furnace exhaust gas flowing downstream after passing through the first heat exchanger. This allows for adjustment of the combustion environment of the calcination furnace with simpler control than in conventional systems.

[0016] In the system described above, the exhaust gas from the calcinerator was cooled by a cooling device, then mixed with a second gas that had a higher oxygen concentration than air to form a first gas. This first gas then exchanged heat with the high-temperature exhaust gas from the calcinerator, raising its temperature, and was then introduced into the calcinerator as a combustion-supporting gas. However, the cooling of the calcinerator exhaust gas by the cooling device may occur after mixing with the second gas.

[0017] In other words, the cement clinker manufacturing system according to the present invention is A furnace is used to burn cement raw materials using the combustion-supporting gas that is introduced. A solid-gas separation device for separating the cement raw materials and furnace exhaust gas discharged from the furnace, A first heat exchanger performs heat exchange between the furnace exhaust gas separated by the solid-gas separator and a first gas containing oxygen at a lower temperature than the furnace exhaust gas. A cooling device that cools the first gas, which is a mixed gas of the calcination furnace exhaust gas whose temperature has decreased after passing through the first heat exchanger and a second gas having a higher oxygen concentration than air, using a cooling medium; A first pipe that guides the first gas that has passed through the cooling device to the first heat exchanger; Another feature is that it includes a second pipe that guides the first gas whose temperature has risen after passing through the first heat exchanger to the calcination furnace as the auxiliary combustible gas.

[0018] The cement clinker production system may include a blower installed in the first pipe and capable of adjusting the mixing ratio of the second gas and the calcination furnace exhaust gas that constitute the first gas.

[0019] As the cooling medium used in the cooling device, any fluid showing cooling performance can be used. Typical examples of the cooling medium include air, water (water vapor), etc.

[0020] As the cooling device, a general-purpose heat exchanger, a boiler, etc. can be used. Examples of general-purpose heat exchangers that can be used as the cooling device include a radiation type heat exchanger, a shell and tube type heat exchanger, etc.

[0021] The first heat exchanger located on the upstream side with respect to the flow direction of the calcination furnace exhaust gas is introduced with extremely high-temperature calcination furnace exhaust gas of about 850°C to 950°C. The first heat exchanger into which such high-temperature gas is introduced requires extremely high heat resistance, and thus the above-mentioned general-purpose heat exchanger that can be used in the cooling device cannot be used, and a dedicated heat exchanger with special use steel materials and structure is used.

[0022] On the other hand, when introduced into the cooling device, the calcination furnace exhaust gas has already been cooled by heat exchange with the first gas by the above-mentioned first heat exchanger (dedicated heat exchanger), so its temperature is lower than about 850°C to 950°C, and typically 500°C or less. Therefore, a general-purpose heat exchanger can be used as the cooling device.

[0023] As described above, the cooling medium can be air. In this case, the cement clinker production system includes a kiln for firing the cement raw material separated by the solid-gas separator, a preheater for preheating the cement raw material before preheating by passing the kiln exhaust gas exhausted from the kiln end of the kiln, a third pipe connecting the preheater and the kiln end of the kiln, and may further include a fourth pipe connecting the air as the cooling medium whose temperature has risen by being used in the cooling device to the third pipe.

[0024] [[ID=1十三]]<0根据上述结构,作为冷却介质而在冷却装置中用于冷却从而温度升高的空气,与流向预热器的窑炉废气合流。由此,能够将该冷却介质所具有的显热有效地利用于水泥原料的预热。

[0025] As described above, the cooling medium can be air. In this case, the cement clinker production system includes a drying device for drying the cement raw material before preheating by using the air as the cooling medium whose temperature has risen by being used in the cooling device, a kiln for firing the cement raw material separated by the solid-gas separator, and may further include a preheater for preheating the cement raw material before preheating by passing the kiln exhaust gas exhausted from the kiln end of the kiln through the cement raw material after passing through the drying device.

[0026] According to the above structure, the sensible heat of the cooling medium whose temperature has risen by being used in the cooling device can be effectively used for drying the cement raw material.

[0027] In this case, as a result of using the air whose temperature has decreased after being used for drying the cement raw material in the drying device, it may be reused as the cooling medium of the cooling device again.

[0028] Furthermore, the cement clinker manufacturing system is A fifth pipe through which the cooling medium, whose temperature has risen after being used in the aforementioned cooling device, flows, A heat utilization device that utilizes the heat of the cooling medium whose temperature has risen, which flows through the fifth pipe, The system may also include a sixth pipe that guides the cooling medium, whose temperature has decreased due to the use of heat in the heat utilization device, to the cooling device.

[0029] Examples of heat utilization devices include power generation equipment and CO2 recovery equipment. In these cases, water (water vapor) can typically be used as a cooling medium.

[0030] Furthermore, the cement clinker manufacturing system is A kiln for firing the cement raw materials separated by the solid-gas separation apparatus, A clinker cooler cools the cement clinker obtained by firing the cement raw materials in the kiln with cooling air, The system may also include a second heat exchanger that exchanges heat between the heated cooling air exhausted from the clinker cooler and the first gas.

[0031] With the above configuration, the sensible heat of the heated cooling air exhausted from the clinker cooler can be used to heat the first gas. [Effects of the Invention]

[0032] According to the cement clinker manufacturing system of the present invention, the temperature of the combustion-supporting gas introduced into the calcination furnace and the temperature of the calcination furnace exhaust gas flowing downstream after passing through the first heat exchanger can be controlled independently, making it possible to adjust the combustion environment of the calcination furnace with simpler control than in the conventional method. [Brief explanation of the drawing]

[0033] [Figure 1] This is a schematic diagram showing the structure of the first embodiment of the cement clinker manufacturing system of the present invention. [Figure 2] This is a partially enlarged view of Figure 1. [Figure 3] This drawing schematically shows another structure of the first embodiment of the cement clinker manufacturing system of the present invention. [Figure 4] This drawing schematically shows another structure of the first embodiment of the cement clinker manufacturing system of the present invention. [Figure 5] This drawing schematically shows another structure of the first embodiment of the cement clinker manufacturing system of the present invention. [Figure 6] This drawing schematically shows another structure of the first embodiment of the cement clinker manufacturing system of the present invention. [Figure 7] This drawing schematically shows another structure of the first embodiment of the cement clinker manufacturing system of the present invention. [Figure 8] This drawing schematically shows another structure of the first embodiment of the cement clinker manufacturing system of the present invention. [Figure 9] This drawing schematically shows another structure of the first embodiment of the cement clinker manufacturing system of the present invention. [Figure 10] This diagram schematically shows a part of the structure of a second embodiment of the cement clinker manufacturing system of the present invention, following Figure 2. [Figure 11] This diagram schematically shows a part of the structure of another embodiment of the cement clinker manufacturing system of the present invention, following Figure 2. [Modes for carrying out the invention]

[0034] Embodiments of the cement clinker manufacturing system according to the present invention will be described below with reference to the drawings as appropriate. Note that the following drawings are schematic representations, and the dimensional ratios in the drawings do not necessarily correspond to the actual dimensional ratios, nor do the dimensional ratios between the drawings necessarily correspond.

[0035] In the following diagrams, gas flow is schematically represented by a dashed line with an arrow, and solid flow is schematically represented by a single dashed line with an arrow.

[0036] [First Embodiment] Figure 1 is a schematic diagram showing the structure of the first embodiment of the cement clinker manufacturing system. Figure 2 is a partially enlarged view of Figure 1.

[0037] As shown in Figures 1 and 2, the cement clinker manufacturing system 1 of this embodiment includes a preheater 2 for preheating the cement raw material M1, a calcination furnace 3 into which the cement raw material M1 preheated by the preheater 2 is fed, and a kiln 40 for firing the cement raw material M1 calcined in the calcination furnace 3 to produce cement clinker.

[0038] The calcination furnace 3 is connected to a part of the solid-gas separation device that makes up the preheater 2 by piping 61, and preheated cement raw material M1 is introduced through piping 61. In the calcination furnace 3, a high-temperature environment is created by burning a fuel (not shown) in an atmosphere of combustion-supporting gas G1 introduced through piping 28. Combustion-supporting gas G1 is a gas whose main components are oxygen and carbon dioxide. Piping 28 corresponds to the "second piping".

[0039] The calcination furnace 3 is provided for the purpose of causing a decarboxylation reaction with respect to the CaCO3 contained in the cement raw material M1. From the viewpoint of promoting this decarboxylation reaction, the temperature of the cement raw material M1 preheated through the piping 61 is 950°C or higher, preferably 960°C to 1,100°C, more preferably 975°C to 1,080°C, and particularly preferably 1,000°C to 1,050°C.

[0040] From the calcinerator 3, calcinerator exhaust gas G2 is discharged through piping 21. The decarbonated cement raw material M2 is transported along with this flow of calcinerator exhaust gas G2 towards the solid-gas separator 11. In the solid-gas separator 11, the cement raw material M2 and the calcinerator exhaust gas G2 are separated into solid and gas phases. Hereafter, the cement raw material after passing through the calcinerator 3 will be referred to as "cement raw material M2" to distinguish it from the cement raw material M1 before it was introduced into the calcinerator 3.

[0041] The cement raw material M2, separated into solid and gas forms by the solid-gas separator 11, is fed into the kiln 40 from the kiln end 41 through the piping 51 and fired in the kiln 40. The kiln 40 fires the cement raw material M2 in a high-temperature environment created by the burner installed at the front of the kiln 42, producing cement clinker. The produced cement clinker is cooled by cooling air GA in the clinker cooler 43 and then sent to the next process.

[0042] The high-temperature exhaust gas (kiln exhaust gas) discharged from the kiln tail end 41 of the kiln 40 is transported to the preheater 2 through piping 52. The preheater 2 preheats the cement raw material M1 by sequentially exchanging heat between the high-temperature kiln exhaust gas and the cement raw material M1 being fed into it.

[0043] The solid-gas separated calcination furnace exhaust gas G2 in the solid-gas separator 11 is sent to the first heat exchanger 5 through the piping 22, where it is primary cooled. As will be described later, a first gas G6, which is colder than the calcination furnace exhaust gas G2, is introduced into the first heat exchanger 5 through the piping 27. In the first heat exchanger 5, heat exchange occurs between the high-temperature calcination furnace exhaust gas G2 exhausted from the solid-gas separator 11 and the first gas G6, which is colder than the calcination furnace exhaust gas G2. The first gas G6 is heated as it passes through the first heat exchanger 5 and is introduced into the calcination furnace 3 as a combustion-supporting gas G1. Piping 27 corresponds to the "first piping".

[0044] The exhaust gas G2 from the furnace passes through the first heat exchanger 5 for primary cooling, and then is sent to the cooling device 7 via piping 23, where it is further cooled. For the sake of explanation, the exhaust gas from the furnace that has been primary cooled by passing through the first heat exchanger 5 will be referred to as "exhaust gas G3 from the furnace" to distinguish it from the exhaust gas G2 from the furnace before passing through the first heat exchanger 5. A cooling medium R1 is introduced into the cooling device 7. Any medium can be used as the cooling medium R1, but typically air, water (water vapor), etc., are used. A general-purpose heat exchanger, boiler, etc., can be used as the cooling device 7.

[0045] In the cement clinker manufacturing system 1 shown in Figures 1 and 2, the calcination furnace exhaust gas G3 that has passed through the first heat exchanger 5 is further cooled by passing through the cooling device 7, and then sent through piping 24 to the CO2 recovery device 31, where CO2 is recovered. For the sake of explanation, the calcination furnace exhaust gas that has been cooled by passing through the cooling device 7 will be referred to as "calcination furnace exhaust gas G4" and distinguished from the calcination furnace exhaust gas G3 before passing through the cooling device 7.

[0046] The cement clinker manufacturing system 1 shown in Figures 1 and 2 is equipped with an oxygen-enriched gas supply device 32. The oxygen-enriched gas supply device 32 is a device that supplies a gas (secondary gas G5) with a higher oxygen concentration than air. For example, the oxygen-enriched gas supply device 32 is an air separation device that generates oxygen from air, or a cylinder containing oxygen gas.

[0047] In the cement clinker manufacturing system 1 shown in Figures 1 and 2, a portion of the cooled calcination furnace exhaust gas G4, which has passed through the cooling device 7, flows through a pipe 25 branched from pipe 24 and is mixed with the second gas G5 that flows through pipe 26 from the oxygen enrichment gas supply device 32. The mixed gas of calcination furnace exhaust gas G4 and the second gas G5 corresponds to the "first gas G6".

[0048] Since the calcination furnace exhaust gas G4 originates from the calcination furnace exhaust gas G2 discharged from calcination furnace 3, it is a gas with a high CO2 concentration. In other words, by adjusting the mixing ratio of calcination furnace exhaust gas G4 and the second gas G5, the oxygen concentration of the first gas G6, which is a mixture of the two, can be adjusted.

[0049] The cement clinker manufacturing system 1 shown in Figures 1 and 2 includes a blower 8. This blower 8 is provided for the purpose of adjusting the flow rate of the furnace exhaust gas G4 introduced through the piping 25. The flow rate of the second gas G5 supplied from the oxygen enrichment gas supply device 32 may be adjustable on the oxygen enrichment gas supply device 32 side.

[0050] The first gas G6, a mixture of the incinerator exhaust gas G4 and the second gas G5, is sent to the first heat exchanger 5 through piping 27. As described above, the incinerator exhaust gas G4 originates from the incinerator exhaust gas G2 discharged from the incinerator 3, which is cooled through the first heat exchanger 5 and the cooling device 7. The second gas G5 supplied from the oxygen-enriched gas supply device 32 is at room temperature. In other words, the first gas G6 supplied to the first heat exchanger 5 through piping 27 is at a lower temperature than the incinerator exhaust gas G2 discharged from the incinerator 3. Therefore, the first gas G6 is heated by heat exchange with the high-temperature incinerator exhaust gas G2 in the first heat exchanger 5. The first gas G6, heated in this way by the first heat exchanger 5, is introduced into the incinerator 3 as the combustion-supporting gas G1. As a result, the combustion-supporting gas G1 is preheated when it is introduced into the incinerator 3, thus achieving high combustion efficiency in the incinerator 3.

[0051] According to the configuration of the cement clinker manufacturing system 1 shown in Figures 1 and 2, the exhaust gas G2 from the calcination furnace 3 is first cooled in the first heat exchanger 5, and then further cooled in the cooling device 7. In other words, the first gas G6, which originates from the temperature of the calcination furnace exhaust gas G4 after passing through the cooling device 7, is introduced into the blower 8. Therefore, if the temperature of the first gas G6 is higher than the heat resistance temperature of the blower 8, the temperature of the first gas G6 can be lowered to below the heat resistance temperature of the blower 8 by increasing the cooling capacity of the cooling device 7. Methods for increasing the cooling capacity of the cooling device 7 include changing the amount, temperature, and substance of the cooling medium R1.

[0052] When the cooling capacity of the cooling device 7 is increased in this way, the temperature of the first gas G6 introduced into the first heat exchanger 5 will decrease. In this case, if the temperature of the combustion-supporting gas G1 introduced into the calcination furnace 3 is low, the temperature of the combustion-supporting gas G1 can be increased by increasing the flow rate and temperature of the calcination furnace exhaust gas G2 discharged from the calcination furnace 3, thereby increasing the heating capacity of the first gas G6 in the first heat exchanger 5. In this case, even if the temperature of the calcination furnace exhaust gas G2 rises, a separate cooling device 7 is provided downstream of the first heat exchanger 5, so by adjusting the cooling capacity of the cooling device 7, it is possible to lower the temperature of the calcination furnace exhaust gas G4 to below the heat resistance temperature of the blower 8.

[0053] In other words, according to the cement clinker manufacturing system 1 of this embodiment, the temperature adjustment (preheating) of the combustion-supporting gas G1 and the cooling of the calcination furnace exhaust gas G2 can be performed independently. As a result, the control to set the temperature environment of the calcination furnace 3 to a desired environment while keeping the temperature of the first gas G6 introduced into the blower 8 below the heat resistance temperature of the blower 8 can be performed with simpler control than in the conventional method.

[0054] The following describes variations of the cement clinker manufacturing system 1 of this embodiment.

[0055] As shown in Figure 3, the cement clinker manufacturing system 1 may also include a second heat exchanger 9 in addition to the first heat exchanger 5 and the cooling device 7. This second heat exchanger 9 performs heat exchange between the first gas G6 (see Figure 2) flowing through the piping 26 and the cooling air GA exhausted from the clinker cooler 43 and heated up for use in cooling the cement clinker. The first gas G6 is sent to the first heat exchanger 5 in a state where it has been preheated by the second heat exchanger 9, and is further heated in the first heat exchanger 5 through heat exchange with the exhaust gas G2 from the calcination furnace.

[0056] As described above, in the cooling device 7, the furnace exhaust gas G3 is cooled by the cooling medium R1. As a result, the temperature of the cooling medium R1 rises. Hereafter, the cooling medium R1 after the temperature rise will be referred to as "cooling medium R2" to distinguish it from the cooling medium R1 before the temperature rise.

[0057] As shown in Figure 4, the cooling medium R2, which has been heated by the cooling device 7, may be combined with the kiln exhaust gas flowing through pipe 52 via pipe 53. When the cooling medium (R1, R2) is air, the high-temperature kiln exhaust gas discharged from the kiln end 41 of the kiln 40 and the heated air cooling medium R2 are combined and sent to the preheater 2 for use in preheating the cement raw material M1. Pipe 52 corresponds to the "third pipe" and pipe 53 corresponds to the "fourth pipe".

[0058] As shown in Figure 5, the cement clinker manufacturing system 1 may include a drying device 33 for drying the cement raw material M1. In this embodiment, air is used as the cooling medium (R1, R2), and the cooling medium R2, which has been heated by use in the cooling device 7, is introduced into the drying device 33 through the piping 54. As a result, high-temperature air is introduced into the drying device 33. The cement raw material M1 passes through the drying device 33, and the drying process is carried out using the sensible heat of the high-temperature air, which is the cooling medium R2. After passing through the drying device 33, the cement raw material M1 is introduced into the preheater 2 through the piping 55.

[0059] In this case, as shown in Figure 6, the cooling media (R1, R2) may be circulated. That is, when the cooling media R2, which has been heated by use in the cooling device 7, is used in the drying device 33 to dry the cement raw material M1, and its temperature drops, making it available again as cooling media R1, this cooling media R1 may be introduced back into the cooling device 7 through the piping 56.

[0060] As shown in Figure 7, the cooling medium R2, which has been heated by the cooling device 7, may be used as a heat source in the CO2 recovery device 31. In this case, air can be used as the cooling medium (R1, R2).

[0061] As another example, the cooling medium (R1, R2) may be water (steam), and the cooling device 7 may be a boiler. In this case, as shown in Figure 8, the heated cooling medium R2, which flows through the pipe 54, is used as a heat source in the CO2 recovery device 31. The cooling medium R2, whose temperature has decreased due to heat utilization in the CO2 recovery device 31, is sent again as cooling medium R1 through the pipe 57 to the cooling device 7, which is a boiler, and used to cool the exhaust gas G3 of the combustion furnace. Pipe 54 corresponds to the "fifth pipe," and pipe 57 corresponds to the "sixth pipe." In this configuration, the CO2 recovery device 31 corresponds to the "heat utilization device."

[0062] In the example shown in Figure 8, the cooling medium (R1, R2) is water (water vapor), and the cooling medium R2 heated in the cooling device 7 is used as a heat source in the CO2 recovery device 31. In contrast, as shown in Figure 9, the cooling medium R2 heated in the cooling device 7 may be used as a heat source in a heat utilization device 34 separate from the CO2 recovery device 31. That is, as shown in Figure 9, the heated cooling medium R2 flowing through the piping 54 is used as a heat source in the heat utilization device 34, and the cooling medium R2 whose temperature has decreased due to heat utilization in the heat utilization device 34 is sent again as cooling medium R1 through the piping 57 to the cooling device 7, which is composed of a boiler, and used to cool the exhaust gas G3 of the combustion furnace. An example of a heat utilization device 34 is a power generation facility. Piping 54 corresponds to the "fifth piping," and piping 57 corresponds to the "sixth piping."

[0063] The variations shown in Figures 3 to 9 can be combined with each other as appropriate.

[0064] [Second Embodiment] A second embodiment of the cement clinker manufacturing system according to the present invention will be described, focusing on the differences from the first embodiment. In the following drawings, the same reference numerals are used for components that are the same as those described above in the first embodiment.

[0065] Figure 10 is a schematic diagram illustrating a part of the structure of the second embodiment of the cement clinker manufacturing system, following Figure 2.

[0066] The cement clinker manufacturing system 1 of this embodiment, shown in Figure 10, differs from the cement clinker manufacturing system 1 of the first embodiment shown in Figure 2 in the position of the cooling device 7, but the other elements are the same.

[0067] In the cement clinker manufacturing system 1 of the first embodiment described above, the cooling device 7 further cools the calcination furnace exhaust gas G3 after it has been cooled in the first heat exchanger 5. The calcination furnace exhaust gas G4, after being cooled in the cooling device 7, is mixed with the second gas G5 supplied from the oxygen enrichment gas supply device 32 and introduced into the first heat exchanger 5 as the first gas G6.

[0068] In contrast, in the cement clinker manufacturing system 1 of this embodiment, the cooling device 7 cools the mixed gas G6a of the calcination furnace exhaust gas G3 and the second gas G5 supplied from the oxygen enrichment gas supply device 32. The mixed gas G6a, after being cooled by the cooling device 7, is introduced into the first heat exchanger 5 as the first gas G6. In other words, the mixed gas G6a corresponds to the gas before it is cooled to the first gas G6 that is introduced into the first heat exchanger 5, and therefore will also be referred to as "first gas G6a" below.

[0069] In this embodiment as well, the same effects as in the cement clinker manufacturing system 1 of the first embodiment can be obtained. That is, according to the configuration of the cement clinker manufacturing system 1 of this embodiment, the exhaust gas G2 from the calcination furnace 3 is first primary cooled in the first heat exchanger 5. After that, the exhaust gas G3 from the calcination furnace, whose temperature has been lowered by primary cooling in the first heat exchanger 5, flows through the piping 25 and is mixed with the second gas G5 to become the first gas G6a, which is then cooled again in the cooling device 7. After that, the first gas G6, whose temperature has been lowered by cooling in the cooling device 7, is sent to the first heat exchanger 5.

[0070] Therefore, by positioning the blower 8 downstream of the cooling device 7 with respect to the flow direction of the gas (in this case, the first gas G6a), the blower 8 receives the first gas G6, which is derived from the temperature of the first gas G6a after it has passed through the cooling device 7. Thus, if the temperature of the first gas G6 is higher than the heat resistance temperature of the blower 8, the temperature of the first gas G6 can be lowered to below the heat resistance temperature of the blower 8 by increasing the cooling capacity of the cooling device 7.

[0071] When the cooling capacity of the cooling device 7 is increased in this way, the temperature of the first gas G6 introduced into the first heat exchanger 5 will decrease. In this case, if the temperature of the combustion-supporting gas G1 introduced into the calcination furnace 3 is low, the temperature of the combustion-supporting gas G1 can be increased by increasing the flow rate and temperature of the calcination furnace exhaust gas G2 discharged from the calcination furnace 3, thereby increasing the heating capacity of the first gas G6 in the first heat exchanger 5. In this case, even if the temperature of the calcination furnace exhaust gas G2 rises, a separate cooling device 7 is provided downstream of the first heat exchanger 5, so by adjusting the cooling capacity of the cooling device 7, it is possible to lower the temperature of the first gas G6 to below the heat resistance temperature of the blower 8.

[0072] In other words, in the cement clinker manufacturing system 1 of this embodiment, as in the first embodiment, the temperature adjustment (preheating) of the combustion-supporting gas G1 and the cooling of the calcination furnace exhaust gas G2 can be performed independently. This makes it possible to control the temperature of the calcination furnace 3 to a desired environment while keeping the temperature of the first gas G6 introduced into the blower 8 below the heat resistance temperature of the blower 8, with simpler control than in the conventional method.

[0073] Furthermore, the variations described above in the first embodiment are also applicable to the cement clinker manufacturing system 1 of this embodiment.

[0074] [Alternative Embodiment] The following describes other embodiments.

[0075] <1> In the first embodiment described above, as shown in Figure 2, the blower 8 was described as being installed in a pipe 27 through which the first gas G6, obtained by mixing the furnace exhaust gas G4 after it has been cooled by the cooling device 7 with the second gas G5 supplied from the oxygen enrichment gas supply device 32, flows. In contrast, the blower 8 may also be installed in a pipe 25 that branches off from pipe 24 and through which the furnace exhaust gas G4 flows.

[0076] However, since the second gas G5 is at a lower temperature than the furnace exhaust gas G4, the first gas G6, which is a mixture of the second gas G5 and the furnace exhaust gas G4, will be at a lower temperature than the furnace exhaust gas G4. Therefore, from the viewpoint of ensuring heat resistance for the blower 8, it is preferable to install the blower 8 in the piping 27 through which the mixed first gas G6 flows, as described above in the first embodiment.

[0077] <2> In the above embodiment, the flow rate of the furnace exhaust gas G4 introduced through the piping 25 is adjusted by the blower 8. Alternatively, as illustrated in Figure 11, a flow control valve 15 may be provided in the piping 25, and the flow rate of the furnace exhaust gas G4 may be adjusted by adjusting the opening of the flow control valve 15. In Figure 11, the flow control valve 15 is provided in the piping 25, but the flow control valve 15 may also be provided in the piping 24 downstream of the branching point between piping 24 and piping 25, and the flow rate of the furnace exhaust gas G4 branched into piping 25 may be adjusted. If a flow control valve 15 is installed, the cement clinker manufacturing system 1 may be configured without a blower 8.

[0078] <3> The cement clinker manufacturing system 1 may be equipped with a dust collector (not shown). In this case, the dust collector is preferably installed downstream of the cooling device 7 with respect to the direction of gas flow.

[0079] (4) The present invention is not limited to the embodiments described above, and includes various modifications. For example, the embodiments described above are described in detail for a better understanding of the present invention and are not necessarily limited to all configurations described. The scope of the present invention is indicated by the claims, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0080] 1: Cement clinker manufacturing system 2: Preheater 3: Kiln 5: First heat exchanger 7 : Cooling device 8: Blower 9: Second heat exchanger 11: Solid-gas separation device 15: Flow control valve 21, 22, 23, 24, 25, 26, 27, 28: Piping 31: CO2 capture device 32: Oxygen-enriched gas supply device 33: Drying equipment 34: Heat utilization equipment 40: Kiln 41: Kiln bottom 42: Front of the kiln 43: Klinka Cooler 51, 52, 53, 54, 55, 56, 57: Piping 61: Piping G1: Combustion-supporting gas G2, G3, G4: Exhaust gas from a calcination furnace G5: Secondary gas G6, G6a: First Gas GA: Cooling air M1, M2: Cement raw materials R1,R2: Cooling medium

Claims

1. Using the combustion-supporting gas introduced, the preheated cement raw materials are calcined in a furnace. A solid-gas separation device for separating the cement raw materials and furnace exhaust gas discharged from the furnace, A first heat exchanger performs heat exchange between the furnace exhaust gas separated by the solid-gas separator and a first gas containing oxygen at a lower temperature than the furnace exhaust gas. A cooling device that further cools the exhaust gas from the incinerator, whose temperature has decreased after passing through the first heat exchanger, using a cooling medium different from the first gas, A first pipe leads the first gas, which is a mixture of the exhaust gas from the furnace that has passed through the cooling device and a second gas with a higher oxygen concentration than air, to the first heat exchanger. A cement clinker manufacturing system characterized by comprising a second pipe that guides the first gas, whose temperature has risen after passing through the first heat exchanger, to the calcination furnace as the combustion-supporting gas.

2. A furnace is used to burn cement raw materials using the combustion-supporting gas that is introduced. A solid-gas separation device for separating the cement raw materials and furnace exhaust gas discharged from the furnace, A first heat exchanger performs heat exchange between the furnace exhaust gas separated by the solid-gas separator and a first gas containing oxygen at a lower temperature than the furnace exhaust gas. A cooling device that cools the first gas, which is a mixture of the exhaust gas from the incinerator whose temperature has decreased after passing through the first heat exchanger, and a second gas with a higher oxygen concentration than air, using a cooling medium, A first pipe that guides the first gas that has passed through the cooling device to the first heat exchanger, A cement clinker manufacturing system characterized by comprising a second pipe that guides the first gas, whose temperature has risen after passing through the first heat exchanger, to the calcination furnace as the combustion-supporting gas.

3. The cement clinker manufacturing system according to claim 1 or 2, characterized in that it is installed in the first piping and comprises a blower capable of adjusting the mixing ratio of the second gas constituting the first gas and the exhaust gas of the calcination furnace.

4. The cement clinker manufacturing system according to claim 1 or 2, characterized in that the cooling medium is air.

5. A kiln for firing the cement raw materials separated by the solid-gas separation apparatus, A preheater that preheats the cement raw material before preheating by passing kiln exhaust gas, which is exhausted from the kiln's tail end, A third pipe connecting the preheater and the kiln's tail, The cement clinker manufacturing system according to claim 4, further comprising a fourth pipe connecting the air used as a cooling medium, whose temperature has risen after being used in the cooling device, to the third pipe.

6. A drying apparatus that dries the cement raw material before preheating using the air used as a cooling medium whose temperature has risen after being used in the aforementioned cooling device, A kiln for firing the cement raw materials separated by the solid-gas separation apparatus, The cement clinker manufacturing system according to claim 4, further comprising a preheater that preheats the cement raw material, which has passed through the drying apparatus and is not yet preheated, by passing kiln exhaust gas exhausted from the kiln's tail through it.

7. A fifth pipe through which the cooling medium, whose temperature has risen after being used in the aforementioned cooling device, flows, A heat utilization device that utilizes the heat of the cooling medium whose temperature has risen, which flows through the fifth pipe, A cement clinker manufacturing system according to claim 1 or 2, further comprising a sixth pipe that guides the cooling medium, whose temperature has decreased due to the use of heat in the heat utilization device, to the cooling device.

8. A kiln for firing the cement raw materials separated by the solid-gas separation apparatus, A clinker cooler cools the cement clinker obtained by firing the cement raw materials in the kiln with cooling air, A cement clinker manufacturing system according to claim 1 or 2, characterized by comprising a second heat exchanger that exchanges heat between the heated cooling air exhausted from the clinker cooler and the first gas.

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