Operational method of chlorine bypass equipment

Abstract

To provide an operational method of chlorine bypass equipment that can be stably operated.SOLUTION: An operational method of chlorine bypass equipment has an extraction step of obtaining extraction gas by extracting kiln exhaust gas generated when calcinating cement raw materials in a cement kiln, and a classification step of obtaining leading-out gas containing fine powder of raw dust by isolating coarse powder of the raw dust from mixed gas obtained by joining the extraction gas and the exhaust gas created in a combustion furnace. The mixed gas is obtained by joining extraction gas with lower temperature than that in extracting in the extraction step and exhaust gas with higher temperature than the extraction gas.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a chlorine bypass facility and an operation method thereof, a cement clinker manufacturing apparatus, and a method for manufacturing cement clinker.

Background Art

[0002] In cement clinker manufacturing apparatuses, efforts are being made to use various wastes as raw materials and fuels. Under such circumstances, the amount of chlorine introduced into the cement kiln tends to increase. Many cement clinker manufacturing apparatuses are equipped with chlorine bypass facilities to reduce chlorine in the cement kiln, and technologies for efficiently removing chlorine from the extracted gas extracted by this chlorine bypass facility are being studied. In Patent Document 1, a technology is proposed in which coarse powder is separated from the extracted gas while maintaining the temperature of the extracted gas extracted from the kiln exhaust gas flow path at 770°C or higher, and then cooled to 600°C or lower to separate chlorine bypass dust.

[0003] Examples of chlorine sources introduced into the cement kiln include waste plastics contained in wastes. Such waste plastics are used not only in the manufacture of cement clinker but also, for example, in the manufacture of solid fuels. For example, Patent Document 2 proposes a technology for manufacturing a solid fuel by heating a mixture containing powder obtained from coal and a thermoplastic plastic such as polyvinyl chloride. In such a technology, when the pyrolysis gas obtained by heating a plastic containing chlorine is burned in a combustion chamber, combustion exhaust gas containing hydrogen chloride is generated. In Patent Document 2, such combustion exhaust gas is treated with an exhaust gas cleaning apparatus.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In Patent Document 1, after separating the coarse powder of dust, the temperature of the extraction gas is set to 770°C or higher to suppress the precipitation of volatilized chlorine components such as KCl and NaCl alone in the classification device or their precipitation on the surface of the raw material dust. However, even when the section from the extraction port to the classification section is insulated, the temperature drop of the extraction gas due to passing through the flow path is inevitable, and it may be difficult to maintain the above-mentioned temperature. When the temperature of the gas passing through the classification section becomes less than 770°C, volatilized chlorine components such as KCl and NaCl precipitate alone in the classification section or precipitate on the surface of the raw material dust to form chlorine bypass dust (clinker dust). The clinker dust immediately after the chlorine component precipitates on the surface or the clinker dust immediately after the chlorine component precipitates alone has very high adhesiveness, and there is a concern that it will adhere to the inside of the classification section and a coating will be generated. In addition, there is also a concern that the volatilized chlorine component precipitates in the classification section and the raw material dust adheres thereto to generate a coating. Thus, when the temperature in the classification section decreases, there is a concern that it will cause fluctuations in the operation of the chlorine bypass facility and the cement clinker production apparatus.

[0006] Therefore, the present disclosure provides a chlorine bypass facility that can be stably operated and an operation method thereof. Further, the present disclosure provides a cement clinker production apparatus and a cement clinker production method capable of stably producing cement clinker by including such a chlorine bypass facility.

Means for Solving the Problems

[0007] The chlorine bypass facility according to one aspect of the present disclosure includes an extraction port that extracts kiln exhaust gas from the kiln end, the rising duct, or between them of a cement kiln, and a classification unit that separates coarse powder of raw material dust from a mixed gas obtained by merging the extracted gas extracted from the extraction port and the exhaust gas generated in the combustion furnace to obtain a derived gas containing fine powder of raw material dust. The mixed gas is obtained by merging the extracted gas having a temperature lower than when extracted at the extraction port and the exhaust gas having a temperature higher than the extracted gas.

[0008] The above chlorine bypass facility obtains a mixed gas by merging the extracted gas extracted from the extraction port and the exhaust gas generated in the combustion furnace into the extracted gas. At this time, the temperature of the extracted gas extracted from the extraction port decreases, for example, by passing through a flow path. Therefore, the exhaust gas of the combustion furnace having a temperature higher than this is merged into the extracted gas having a temperature lower than when extracted at the extraction port in this way to obtain a mixed gas. In this way, since the high-temperature exhaust gas is merged, the temperatures of the mixed gas and the derived gas can be stably increased. For this reason, in the classification unit, in a state where the chlorine content is contained in the gas phase, the coarse powder of the raw material dust contained in the extracted gas is separated from the mixed gas, and a derived gas with a reduced amount of coarse powder of the raw material dust compared to the extracted gas and the mixed gas can be obtained. Therefore, an increase in the amount of clinker dust can be suppressed, and the load on the clinker dust water washing facility can be reduced. Furthermore, it is possible to suppress the chlorine content from depositing alone or depositing on the surface of the raw material dust to form clinker dust and adhering inside the classification unit to cause blockage. As a result, the above-described chlorine bypass facility can be stably operated. In addition, since the coarse powder of the raw material dust separated in the classification unit has a sufficiently low chlorine concentration, it can be returned to the cement kiln side and effectively used as a raw material for cement clinker.

[0009] The derived gas led out from the classification section of the chlorine bypass facility preferably has a temperature of 770 °C or higher. Thereby, it is possible to sufficiently suppress the volatilized chlorine components such as KCl and NaCl from depositing alone or depositing on the surface of the raw material dust to form clinker dust. Further, even when the coarse powder of the raw material dust is returned to the cement kiln, it is possible to reduce the introduction of chlorine into the cement kiln.

[0010] The combustion furnace burns the pyrolysis gas generated by heat-treating plastic, and the exhaust gas preferably contains chlorine components. The pyrolysis gas contains, for example, tar. The derived gas led out from the classification section contains the coarse powder and fine powder of the raw material dust that were not recovered in the classification section. The Ca component contained in the raw material dust that was not recovered in this classification section reacts with the chlorine components such as HCl contained in the exhaust gas obtained by burning the pyrolysis gas to form solid CaCl2, and these can also be recovered as clinker dust. Therefore, it is possible to reduce the load on the scrubber for treating the exhaust gas of the combustion furnace containing chlorine components. Further, if the total amount of the exhaust gas of the combustion furnace containing chlorine components is made to merge into the extraction gas, the exhaust gas scrubber can also be eliminated.

[0011] The chlorine bypass facility preferably includes a cooling gas introduction section for introducing a cooling gas so that a swirling flow is generated along the inner wall surface of the flow path through which the derived gas flows. In the derived gas containing fine powder of the raw material dust and volatilized chlorine components, as the temperature decreases, the chlorine components precipitate, or the chlorine components precipitate on the surface of the fine powder of the raw material dust, forming clinker dust. There is concern that the clinker dust immediately after the chlorine components precipitate on the surface has very high adhesiveness and adheres to the inner wall surface of the flow path to form a coating. There is also concern that the volatilized chlorine components precipitate on the inner wall surface of the flow path and the raw material dust adheres thereto to form a coating.

[0012] Therefore, a cooling gas introduction part is provided for introducing cooling gas so that a swirling flow is generated along the wall surface of the flow path of the derived gas. By introducing the cooling gas in such a manner that a swirling flow is generated along the inner wall surface, the inner wall surface can be protected from the high-temperature derived gas. Then, the high-temperature derived gas mainly flows through the central part of the flow path. Therefore, the flow paths of the derived gas and the cooling gas in the flow path are different. Although a small amount of clinker dust is formed at the boundary between the flow path of the derived gas and the flow path of the cooling gas, the swirling flow along the inner wall surface of the flow path functions as an air curtain, and it is possible to suppress the clinker dust from adhering to the inner wall surface of the flow path to form a coating. Therefore, the chlorine bypass facility can be operated more stably. Note that examples of the "gas containing the derived gas" in the present disclosure include the derived gas before mixing with the cooling gas and the gas obtained by mixing the derived gas and the cooling gas. However, other gases may be included.

[0013] Preferably, a recovery part for recovering the clinker dust contained in the gas containing the derived gas obtained by cooling the above-mentioned derived gas and a suction part for sucking the gas containing the derived gas on the downstream side of the recovery part are provided. In the recovery part, the clinker dust can be recovered by suction by the suction part. Since the coarse powder of the raw material dust is reduced in the classification part, the amount of the clinker dust can be reduced, and the cost of washing the clinker dust can be reduced.

[0014] The chlorine bypass facility preferably includes a circulation flow path for returning the coarse powder of the raw material dust separated in the classification part to the cement kiln side. Since the coarse powder of the raw material dust contained in the mixed gas is separated and returned to the cement kiln side through the circulation flow path while maintaining the temperature of the mixed gas at 770°C or higher, the chlorine component is in a volatile state, and the raw material dust can be effectively utilized as a cement clinker raw material.

[0015] The cement clinker manufacturing apparatus according to one aspect of the present disclosure includes any of the above-described chlorine bypass facilities. Therefore, since the chlorine bypass facility can operate stably, the cement clinker manufacturing apparatus including the same can stably manufacture cement clinker.

[0016] The method for manufacturing cement clinker according to one aspect of the present disclosure manufactures cement clinker using the above-described cement clinker manufacturing apparatus. Therefore, cement clinker can be stably manufactured.

[0017] The operation method of the chlorine bypass facility according to one aspect of the present disclosure includes an air extraction step of extracting kiln exhaust gas generated when firing cement raw materials in a cement kiln to obtain extracted gas, and a classification step of separating coarse powder of raw material dust from the mixed gas obtained by merging the extracted gas and the exhaust gas generated in the combustion furnace to obtain derived gas containing fine powder of raw material dust, and the extracted gas having a lower temperature than when extracted in the air extraction step and exhaust gas having a higher temperature than the extracted gas are merged to obtain the mixed gas.

[0018] The above operation method obtains a mixed gas by merging the extracted gas extracted in the air extraction step and the exhaust gas generated in the combustion furnace. At this time, the temperature of the extracted gas extracted in the air extraction step decreases, for example, by passing through a flow path. Therefore, by merging exhaust gas having a higher temperature with the extracted gas having a lower temperature than when extracted in the air extraction step in this way, the temperature of the mixed gas can be stably increased. Therefore, in the classification step, in a state where chlorine is contained in the gas phase, coarse powder of raw material dust can be separated from the mixed gas to obtain derived gas with less coarse powder of raw material dust than the extracted gas and the mixed gas. Thereby, an increase in the amount of clinker dust can be suppressed, and the load on the clinker dust water washing facility can be reduced. Further, since precipitation of chlorine can be suppressed in the classification step, generation of coating in the facility can be suppressed. Due to these factors, the above operation method can stably operate the chlorine bypass facility.

[0019] In the classification step, it is preferable to maintain the temperature of the mixed gas at 770°C or higher. By separating the coarse powder of the raw material dust contained in the mixed gas and returning it to the cement kiln side through a circulation path, since the chlorine content is in a volatile state, the raw material dust can be effectively utilized as a cement clinker raw material.

[0020] The above operation method preferably has a preheating step of preheating a classification section that separates the coarse powder of the raw material dust from the mixed gas to obtain a derived gas containing fine powder of the raw material dust using the above exhaust gas before starting the classification step. By having such a preheating step, it is possible to suppress the precipitation of chlorine alone or the precipitation on the surface of the raw material dust to generate clinker dust in the classification section from the initial stage of starting the use of the classification section.

[0021] The above operation method includes a cooling gas introduction step of introducing a cooling gas so that a swirling flow is generated in the flow path through which the derived gas obtained by separating the coarse powder of the raw material dust from the above mixed gas flows, and a dust collection step of collecting the clinker dust contained in the gas containing the derived gas and the cooling gas. By having the cooling gas introduction step, the swirling flow in the flow path can become an air curtain, and it is possible to suppress the adhesion of the clinker dust to the inner wall surface of the flow path. Therefore, the clinker dust can be stably collected by the dust collection step.

Effects of the Invention

[0022] It is possible to provide a chlorine bypass facility that can operate stably and its operation method. Further, by providing such a chlorine bypass facility, it is possible to provide a cement clinker manufacturing apparatus and a method for manufacturing cement clinker that can stably manufacture cement clinker.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

[0024] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings as needed. However, the following embodiment is an example for explaining the present disclosure, and is not intended to limit the present disclosure to the following content. In the description, the same reference numerals are used for the same elements or elements having the same functions, and redundant descriptions are omitted as the case may be. In addition, the positional relationships such as up, down, left, right, etc. are based on the positional relationships shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios of each element are not limited to the ratios shown in the drawings.

[0025] 1 is a diagram showing a chlorine bypass equipment according to one embodiment and a cement clinker manufacturing apparatus equipped with the same. The chlorine bypass equipment 90 is connected to a rising duct 42 of a preheating and calcining section 40 of a cement clinker manufacturing apparatus 100. The chlorine bypass equipment 90 recovers volatile matters such as chlorine content in the cement clinker manufacturing apparatus 100 as clinker dust, and reduces the chlorine content in the cement clinker manufacturing apparatus 100.

[0026] The chlorine bypass equipment 90 includes an extraction port 21A that extracts gas from the rising duct 42, an extraction pipe 21 through which the extraction gas containing raw material dust extracted from the extraction port 21A flows, a classification section 22 that combines the extraction gas with exhaust gas generated in the combustion furnace 32 to obtain a mixed gas and separates coarse particles of the raw material dust from the mixed gas to obtain an outlet containing fine particles of raw material dust smaller than the coarse particles, a flow path 24 through which the outlet gas flows, and a cooling gas introduction section 10 that introduces a cooling gas so as to generate a swirling flow in the flow path 24.

[0027] The extraction gas extracted from the extraction port 21A contains raw material dust and gaseous chlorine components. The extraction gas flows through the extraction pipe 21 and is introduced into the classification section 22. The extraction pipe 21 may be referred to as an extraction probe. From the viewpoint of suppressing the volatilized chlorine components such as KCl and NaCl from precipitating alone or precipitating on the surface of the raw material dust and adhering to the classification section 22 as clinker dust, the temperature of the extraction gas when introduced into the classification section 22 is preferably higher than 770 °C, more preferably 820 °C or higher, and still more preferably 860 °C or higher.

[0028] In the classification section 22, the extraction gas and the exhaust gas generated in the combustion furnace 32 are introduced, and the two are mixed in the classification section 22 to obtain a mixed gas containing the extraction gas and the exhaust gas. The combustion furnace 32 is a furnace that burns the tar contained in the pyrolysis gas generated by heat-treating the raw material containing waste plastic in the desalting furnace 35 in the waste plastic desalination facility 30. The exhaust gas generated in the combustion furnace 32 flows through the flow path 33 and is introduced into the classification section 22. At this time, the exhaust gas of the combustion furnace having a higher temperature than the extraction gas whose temperature has decreased by flowing through the extraction pipe 21 is introduced. Thereby, the temperature of the mixed gas (derived gas) in the classification section 22 can be stably increased. Therefore, in the classification section 22, the coarse powder of the raw material dust can be separated from the mixed gas in a state where the chlorine component is contained in the gas phase. Therefore, it is possible to suppress the volatilized chlorine component from precipitating alone or precipitating on the surface of the raw material dust to cause coating and block the classification section 22. In addition, it is possible to suppress the raw material dust with precipitated chlorine from returning to the cement kiln side through the circulation flow path.

[0029] By merging the exhaust gas from the combustion furnace 32 and the extraction gas, the flow velocity of the mixed gas in the classification section 22 can be increased. As a result, the classification performance in the classification section 22 can be improved, and the coarse powder of the raw material dust can be separated from the mixed gas with higher accuracy. The classification section 22 may be, for example, a cyclone. The particle size of the coarse powder of the raw material dust may be, for example, 18 μm or more, preferably 16 μm or more, and more preferably 14 μm or more. By performing classification so that the coarse powder of the raw material dust is 14 μm or more, the volatile matter can be sufficiently reduced.

[0030] Since the coarse powder of the raw material dust separated from the mixed gas in the classification section 22 becomes the raw material for the cement clinker, the coarse powder of the raw material dust flows through the circulation passage 27 and is introduced into the kiln end 52 of the cement kiln 50. In this way, by returning the coarse powder of the raw material dust extracted from the extraction port 21A to the kiln end 52, the coarse powder of the raw material dust can be used for the production of the cement clinker. Note that the coarse powder of the raw material dust may be returned not to the kiln end 52 but to the rising duct 42, the calciner 44, or the kiln body 56. Also, a plurality of circulation passages 27 may be provided to return the coarse powder of the raw material dust to a plurality of locations. From the viewpoint of suppressing the precipitation of chlorine in the coarse powder of the raw material dust separated from the mixed gas in the classification section 22, the temperature of the mixed gas when separating the coarse powder of the raw material dust in the classification section 22 is preferably 770 °C or higher, more preferably 820 °C or higher, and even more preferably 860 °C or higher. The temperature of the gas derived from the classification section 22 is also preferably 770 °C or higher, more preferably 820 °C or higher, and even more preferably 860 °C or higher.

[0031] The exhaust gas generated in the combustion furnace 32 and flowing through the flow path 33 and merging with the extraction gas at the classification unit 22 or its inlet may contain chlorine components such as HCl. The derived gas derived from the classification unit 22 contains coarse powder and fine powder of the raw material dust not recovered in the classification unit 22. The Ca component contained in the raw material dust not recovered in the classification unit 22 reacts with the chlorine component such as HCl contained in the exhaust gas generated in the combustion furnace 32 to form solid CaCl2, and such chlorine components can also be recovered as clinker dust in the chlorine bypass facility 90. Therefore, the load on the cleaning device in the waste plastic dechlorination facility 30 can be reduced. Further, by introducing the entire amount of the exhaust gas containing chlorine components generated in the combustion furnace 32 into the chlorine bypass facility 90, the operation of the cleaning device in the waste plastic dechlorination facility 30 can be omitted.

[0032] Note that the exhaust gas merging with the extraction gas in the chlorine bypass facility 90 is not limited to the exhaust gas from the combustion furnace 32 of the waste plastic dechlorination facility 30, and may be exhaust gas from a combustion furnace different from the combustion furnace 32 of the waste plastic dechlorination facility 30. Further, it may be exhaust gas not containing chlorine components. For example, it may be exhaust gas from a combustion furnace provided in a biomass pellet carbonization facility, an ammonia gasification furnace, a sulfur combustion furnace, or a high-temperature exhaust gas from a combustion furnace or melting furnace different from these. One kind of these exhaust gases may be used alone, or a plurality of exhaust gases may be used in combination.

[0033] The flow rate of the exhaust gas merging with the extraction gas may be adjusted according to the operating conditions of the cement clinker manufacturing apparatus 100 or the chlorine bypass facility 90. The adjustment of the flow rate of the exhaust gas may be performed, for example, based on the operating information of the flow path 24 of the extraction gas, the classification unit 22, the extraction pipe 21, the rising duct 42, the cement kiln 50 (kiln end 52), and / or the chlorine concentration of the clinker dust recovered in the recovery unit 72. Specifically, based on the operating information (e.g., temperature) of the classification unit 22 and / or the chlorine concentration of the clinker dust recovered in the recovery unit 72, the operator may manually adjust the flow rate of the exhaust gas, or may automatically adjust it using a control unit.

[0034] Examples of the operation information measured by the measurement unit include temperature, pressure, components of the exhaust gas, flow rate of the exhaust gas, dust concentration, and images. Specifically, the temperature inside or on the surface of the exhaust pipe 21, the classification unit 22, and the flow path 24, the temperature of the kiln exhaust gas in the rising duct 42 and the kiln bottom 52, the temperature of the kiln exhaust gas flowing into the exhaust pipe 21 from the exhaust port 21A, the pressure of the kiln exhaust gas and the exhaust gas, the gas components of the kiln exhaust gas and the exhaust gas, the dust concentration contained in the kiln exhaust gas and the exhaust gas, and images inside the exhaust pipe 21 and the classification unit 22, etc. are included. Examples of the measurement unit include a temperature sensor, a pressure sensor, a gas component sensor, a flow rate sensor, and a camera, etc.

[0035] The chlorine bypass facility 90 may include a control unit that outputs a control signal for adjusting the flow rate of the exhaust gas based on the operation information measured by the measurement unit. The control unit may be a normal computer system and may include, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and an input / output interface, etc.

[0036] By providing the control unit, the flow rate of the exhaust gas from the combustion furnace 32 can be automatically controlled. For example, the temperature T1 of the derived gas derived from the classification unit 22 is measured by the measurement unit, and when the temperature T1 falls below the lower limit, the flow rate of the exhaust gas that joins the exhaust gas may be controlled to increase. Thereby, it is possible to avoid the temperature of the classification unit 22 from dropping too much.

[0037] The derived gas containing fine powder of the raw material dust and gaseous chlorine component obtained by separating the coarse powder of the raw material dust from the mixed gas in the classification unit 22 flows through the flow path 24 connected to the classification unit 22 and is cooled by the cooling gas introduction unit 10. In the cooling gas introduction unit 10, the flow path of the cooling gas 11 is connected to the flow path 24 formed by the circular pipe 26, and the derived gas containing fine powder of the raw material dust and chlorine component is mixed with the cooling gas and cooled. After cooling, the gas containing the derived gas flows through the flow path 24 and is introduced into the cooling unit 70.

[0038] In the cooling gas introduction section 10, the cooling gas 11 is introduced along the circumferential direction of the inner wall surface of the flow path 24 through which the outlet gas containing fine powder of raw material dust and chlorine content flows. Thereby, a swirling flow is generated in the flow path 24, and it is possible to suppress the adhesion of clinker dust to the inner wall surface of the flow path 24 and the occurrence of coating. Such a swirling flow forms an air curtain at the outer peripheral portion of the flow path 24 and can protect the inner wall surface of the circular pipe 26 constituting the flow path 24 from the high-temperature outlet gas.

[0039] In the cooling gas introduction section 10, the outlet gas is mixed with the cooling gas 11 and cooled. The temperature of the gas containing the cooled outlet gas (the mixed gas of the outlet gas and the cooling gas) may be 600°C or lower, and may also be 500°C or lower, from the viewpoint of the heat resistance of the equipment. The cooling gas 11 may be normal-temperature air, or may contain exhaust gas at 200°C or lower, preferably 100°C or lower, generated in a factory or the like. Examples of the exhaust gas include odor gas generated during the acceptance, storage, and fermentation of water-containing sludge such as sewage sludge brought into a cement manufacturing factory, and exhaust gas discharged from the suction section 74 described later and suction sections of other processes. These can be used alone or in combination of two or more.

[0040] FIG. 2 is a cross-sectional view showing a radial cross-section of the flow path 24 of the outlet gas to which the cooling gas introduction section is connected. The flow path 24 through which the coarse powder of the raw material dust is separated and the outlet gas containing chlorine content and fine powder of the raw material dust flows is constituted by a circular pipe 26. When viewed in the radial cross-section of the flow path 24 (circular pipe 26) as shown in FIG. 2, the flow path wall 37 of the cooling gas introduction section 10 is connected to the circular pipe 26 so as to extend in a direction parallel to the tangential direction of the circular pipe 26. The cooling gas introduction section 10 connected to the circular pipe 26 introduces the cooling gas 11 flowing through the flow path 12 partitioned by the flow path wall 37 into the flow path 24. The introduced cooling gas 11 forms a swirling flow SF while merging with the outlet gas in the flow path 24. The axis of rotation of the swirling flow SF coincides with the central axis P of the flow path 24 constituted by the circular pipe 26.

[0041] The derived gas flows through the central part of the flow path 24 along the axial direction of the central axis P, and the cooling gas 11 flows as a swirling flow SF along the inner wall surface 26W of the circular pipe 26 that constitutes the flow path 24. In this way, in the flow path 24, the gases are made to flow so that the flow paths of the derived gas and the cooling gas are different. Although a small amount of clinker dust is formed at the boundary between the flow path of the derived gas and the flow path of the cooling gas, the swirling flow SF can become an air curtain to suppress the adhesion of the clinker dust to the inner wall surface 26W and prevent it from becoming a coating.

[0042] As shown in FIG. 1, the chlorine bypass facility 90 includes a cooling unit 70 that cools the gas containing the derived gas downstream of the cooling gas introduction unit 10, a recovery unit 72 that recovers dust (clinker dust) contained in the gas containing the derived gas from the gas containing the derived gas, and a suction unit 74 that sucks the derived gas. The cooling unit 70 may be a water-cooled or air-cooled heat exchanger. Examples of the suction unit 74 include ordinary suction fans such as a sirocco fan and a turbo fan.

[0043] The cooling unit 70 cools the gas containing the derived gas obtained by the confluence of the cooling gas 11 and the derived gas to, for example, less than 260°C, preferably less than 200°C. Since this gas containing the derived gas contains clinker dust, it is introduced into the recovery unit 72. The recovery unit 72 may be a bag filter or a wet dust collector such as a wet scrubber. The clinker dust recovered by the recovery unit 72 may be blended into the cement composition after being subjected to a water washing treatment, or may be used as a cement raw material.

[0044] The cement clinker production apparatus 100 in FIG. 1 includes a chlorine bypass facility 90, a preheating and calcining unit 40 that preheats and calcines the cement raw material, a cement kiln 50 that burns the preheated and calcined cement raw material to obtain cement clinker, and a clinker cooler 60 that cools the cement clinker obtained by the cement kiln 50. The preheating and calcining unit 40 has four cyclones C1, C2, C3, C4 (preheaters) and a calcining furnace 44.

[0045] The kiln end 52 of the cement kiln 50 and the calciner 44 of the preheating and calcining section 40 are connected by a rising duct 42. Near the connection part of the rising duct 42 and the kiln end 52, an extraction port 21A of a chlorine bypass facility 90 for extracting the kiln exhaust gas generated in the cement kiln 50 and recovering the dust contained in the kiln exhaust gas is provided. An extraction pipe 21 is connected to the extraction port 21A. By including the chlorine bypass facility 90, the cement clinker manufacturing apparatus 100 can reduce the chlorine content in the cement clinker manufacturing apparatus 100.

[0046] The cement raw material introduced from the connection part between the cyclone C1 and the cyclone C2 flows through the cyclone C1, the cyclone C2, the cyclone C3, the rising duct 42, the calciner 44, and the cyclone C4 and is introduced into the kiln end 52 of the cement kiln 50. In the cement kiln 50, the preheated and calcined cement raw material is heated by the combustion of a burner 54 provided on the side opposite to the kiln end 52 to become cement clinker. The obtained cement clinker is cooled by a clinker cooler 60. After being cooled by the clinker cooler 60, cement clinker is obtained.

[0047] Since the cement clinker manufacturing apparatus 100 includes the chlorine bypass facility 90, it can be operated stably, and cement clinker can be manufactured stably. Also, the raw material dust can be effectively utilized to increase the yield of cement clinker. Further, the clinker dust is reduced, and the processing cost of the clinker dust can be reduced.

[0048] In this embodiment, the air extraction port 21A is provided in the rising duct 42, but it is not limited thereto. For example, in a modified example, the air extraction port 21A may be provided at the kiln end 52, or may be provided between (or at the boundary) the kiln end 52 and the rising duct 42. Further, in this embodiment, the exhaust gas generated from the combustion furnace 32 merges with the extraction gas in the classification section 22, but it is not limited thereto. In a modified example, the extraction gas and the exhaust gas may merge in the flow path in the extraction pipe 21, for example, between the classification section 22 and the air extraction port 21A to form a mixed gas. In this case, by connecting the exhaust gas flow path 33 and the extraction pipe 21, the merging portion of the extraction gas and the exhaust gas can be provided upstream of the classification section 22. Here, the "upstream" refers to the positional relationship between the merging portion and the classification section 22 based on the flow direction of the extraction gas (mixed gas). Since the mixed gas obtained by the merging of the extraction gas and the exhaust gas is sufficiently high in temperature, the precipitation of chlorine components is suppressed, and the adhesion and blockage of coating in the classification section 22 can be suppressed. In another modified example, the exhaust gas flow path 33 may be branched so that the exhaust gas is divided into a plurality of locations and merged with the extraction gas or the mixed gas. In this case, a control unit may be provided to individually adjust the flow rate of the exhaust gas merging at the plurality of merging portions.

[0049] The method for manufacturing cement clinker according to an embodiment can be carried out using the cement clinker manufacturing apparatus 100. These methods include a preheating and calcining step of preheating and calcining cement raw materials in the preheating and calcining section 40, a firing step of introducing the preheated and calcined cement raw materials from the kiln tail 52 into the kiln main body 56 to manufacture cement clinker, an extraction step of extracting the kiln exhaust gas generated in the firing step to obtain extraction gas, a merging step of merging the extraction gas containing raw material dust and the exhaust gas generated in the combustion furnace, a classification step of separating the coarse powder of the raw material dust from the mixed gas obtained by the merging of the extraction gas and the exhaust gas in the classification section 22, a cooling gas introduction step of introducing cooling gas so that a swirling flow is generated in the flow path through which the derived gas with reduced coarse powder of the raw material dust flows out from the classification section 22, a cooling step of cooling the gas containing the derived gas, and a dust recovery step of recovering the clinker dust contained in the gas containing the derived gas cooled in the cooling step. Further, it may have a circulation step of returning the coarse powder of the raw material dust separated in the classification step to the cement kiln 50 side. Further, it may have a clinker cooling step of cooling the cement clinker obtained in the firing step with the clinker cooler 60.

[0050] In the preheating and calcining step, the cement raw materials are introduced from the flow path between the cyclone C1 and the cyclone C2. The cement raw materials are preheated by flowing through the cyclone C1, the cyclone C2, and the cyclone C3. Then, they are introduced into the calcining furnace 44 and calcined. The calcining furnace 44 may be provided with a burner for burning fuels such as coal. The cement raw materials (calcined raw materials) calcined in the calcining furnace 44 are introduced into the cyclone C4 and heated.

[0051] In the firing process, the calcined raw material heated in the cyclone C4 is introduced into the kiln end 52. Then, it is fired in the kiln main body 56 to become cement clinker. In the exhaust process, the kiln exhaust gas generated in the firing process is exhausted from the exhaust port 21A. In the confluence process, the exhaust gas whose temperature has decreased by passing through the flow path after being exhausted from the exhaust port is made to merge with the exhaust gas of the combustion furnace having a higher temperature than this. Thereby, the temperature of the mixed gas in the classification process can be stably increased. Therefore, in the classification process, the coarse powder of the raw material dust can be separated from the mixed gas in a state where the chlorine content is contained in the mixed gas as a gas phase. Therefore, it is possible to suppress the occurrence of coating due to the volatilized chlorine content precipitating alone or on the surface of the raw material dust, and the clogging of the classification section 22. Further, it is possible to suppress the return of the raw material dust on which chlorine has precipitated to the cement kiln side through the circulation path.

[0052] The confluence process and the classification process may be carried out together in the classification section 22, or after performing the confluence process in the confluence section provided in the exhaust pipe 21 to obtain a mixed gas, a classification process of separating the coarse powder of the raw material dust from the mixed gas may be performed in the classification section 22. By performing a circulation process of returning the coarse powder of the raw material dust obtained in the classification process to the kiln end 52 of the cement kiln 50, the production amount of cement clinker can be efficiently increased.

[0053] When starting the classification process, there is a concern that clinker dust may adhere to the inner wall surface of the flow path when the extraction gas passes through the unheated extraction pipe 21 and the classification unit 22. Therefore, a preheating process may be performed to preheat the inside of the extraction pipe 21 and the classification unit 22 using the exhaust gas generated from the combustion furnace 32. Examples of the preheating location include the extraction pipe 21 forming the flow path from the extraction port 21A where the refractory is constructed to the classification unit 22, and the classification unit 22. When using the draft of the suction unit 74 during preheating, a damper is provided near the extraction port 21A, and after preventing the extraction of the kiln exhaust gas containing the volatilized chlorine component extracted from the extraction port 21A, it is preferable to introduce the exhaust gas generated in the combustion furnace 32 from a location near the damper. When using the draft of the SP fan during preheating, it is preferable to provide a damper at the gas outlet of the classification unit 22 and introduce high-temperature exhaust gas into the classification unit 22. Also, from the viewpoint of suppressing the precipitation of chlorine on the inner wall surface of the flow path, it is preferable that the high-temperature exhaust gas used for preheating does not contain chlorine.

[0054] In the cooling gas introduction process, the cooling gas is merged with the derived gas derived from the classification unit 22 to cool the derived gas. At this time, a swirling flow is generated by introducing the cooling gas along the circumferential direction of the inner wall surface of the gas flow path 24 including the derived gas composed of the circular pipe 26. Thereby, it is possible to suppress the adhesion of clinker dust to the flow path 24 and the occurrence of coating. The temperature of the gas containing the derived gas cooled by mixing the cooling gas 11 in the cooling gas introduction process may be 600 ° C or lower, and may be 500 ° C or lower from the viewpoint of the heat resistance of the equipment. When the derived gas is cooled in this way, the volatilized chlorine component precipitates alone or on the surface of the raw material dust to form clinker dust.

[0055] In the cooling process, for example, in the cooling unit 70 equipped with a heat exchanger, the gas containing the derived gas is cooled to, for example, less than 260°C, preferably less than 200°C. In the dust collection process, the dust contained in the gas containing the derived gas cooled in the collection unit 72 is collected. The dust thus collected is called clinker dust. By this manufacturing method, the chlorine bypass facility 90 and the cement clinker manufacturing apparatus 100 can be stably operated. Also, the raw material dust can be effectively utilized to efficiently manufacture cement clinker. Further, by separating the coarse powder of the raw material dust in the classification process, the amount of clinker dust is reduced, and the processing cost of the clinker dust can be reduced.

[0056] The operation method of the chlorine bypass facility according to one embodiment may include the above-described air extraction process, confluence process, classification process, cooling process, and dust collection process. Further, it may include the above-described circulation process, or may further include any of the processes of the above-described cement clinker manufacturing method. This operation method can be performed using the chlorine bypass facility 90 provided in the cement clinker manufacturing apparatus 100. Therefore, the content of each process may be the same as the content in the above-described cement clinker manufacturing method.

[0057] The description content regarding the above-described chlorine bypass facility 90 and cement clinker manufacturing apparatus 100 is also applicable to the description content of the above-described cement clinker manufacturing method and the operation method of the chlorine bypass facility. Also, the description content of the above manufacturing method and operation method is applicable to the description content of the above-described chlorine bypass facility 90 and cement clinker manufacturing apparatus 100.

[0058] As described above, several embodiments of the present disclosure have been explained, but the present disclosure is not limited to the above embodiments in any way. For example, in the above embodiments, the coarse powder of the raw material dust separated by the classification unit 22 was returned to the cement kiln 50 side via the circulation channel 27, but it is not limited to this. For example, it may be put into a tank of the cement raw material and supplied to the preheating and calcining unit 40 as the cement raw material. Further, the circular pipe 26 constituting the flow path 24 of the exhaust gas may be arranged not horizontally but inclined with respect to the horizontal direction. The chlorine bypass facility may have a mixing chamber between the cooling gas introduction unit 10 and the cooling unit 70.

[0059] The present disclosure includes the following [1] to [9]. [1] An extraction port for extracting kiln exhaust gas from the kiln end, rising duct or between them of a cement kiln, An extraction pipe through which the extraction gas containing the raw material dust extracted from the extraction port flows, A classification unit that separates the coarse powder of the raw material dust from the mixed gas obtained by merging the extraction gas having a temperature lower than that when extracted at the extraction port by flowing through the extraction pipe and the exhaust gas generated in a combustion furnace having a temperature higher than that of the extraction gas, to obtain the extraction gas containing the fine powder of the raw material dust. A chlorine bypass facility. [2] The chlorine bypass facility according to [1], wherein the classification unit is configured to derive the extraction gas having a temperature of 770 °C or higher. [3] A dechlorination furnace in which pyrolysis gas is generated by heat-treating plastic, The combustion furnace that burns the pyrolysis gas, and The chlorine bypass facility according to [1] or [2], wherein the exhaust gas generated in the combustion furnace contains chlorine. [4] The chlorine bypass facility according to any one of [1] to [3], comprising a cooling gas introduction unit that introduces cooling gas so that a swirling flow is generated along the inner wall surface of the flow path through which the extraction gas derived from the classification unit flows. [5] A cement clinker production apparatus including the chlorine bypass facility according to any one of [1] to [4]. [6] A method for manufacturing cement clinker using the cement clinker manufacturing apparatus according to [5]. [7] An exhaust gas extraction step of extracting kiln exhaust gas generated when firing cement raw materials in a cement kiln to obtain an extracted gas, and a classification step of separating coarse powder of raw material dust from a mixed gas obtained by merging the extracted gas and the exhaust gas generated in a combustion furnace to obtain a derived gas containing fine powder of the raw material dust. An operation method of a chlorine bypass facility for obtaining the mixed gas by merging the extracted gas having a temperature lower than that when extracted in the exhaust gas extraction step and the exhaust gas having a temperature higher than that of the extracted gas. [8] Before starting the classification step, a preheating step of preheating a classification unit that separates the coarse powder from the mixed gas to obtain the derived gas containing the fine powder using the exhaust gas. The operation method of the chlorine bypass facility according to [7]. [9] A cooling gas introduction step of introducing a cooling gas so that a swirling flow is generated in a flow path through which the derived gas flows, and a dust collection step of collecting dust contained in the gas containing the derived gas and the cooling gas. The operation method of the chlorine bypass facility according to [7] or [8].

Industrial Applicability

[0060] According to the present disclosure, a chlorine bypass facility capable of operating stably and an operation method thereof are provided. Further, by providing such a chlorine bypass facility, a cement clinker manufacturing apparatus and a method for manufacturing cement clinker capable of stably manufacturing cement clinker are provided.

Explanation of Signs

[0061] 10…Cooling gas introduction section, 11…Cooling gas, 12, 24, 33…Flow paths, 21…Exhaust pipe, 21A…Exhaust port, 22…Classification section, 26…Circular pipe, 26W…Inner wall surface, 27…Circulation flow path, 30…Waste plastic desalination facility, 32…Combustion furnace, 35…Desalination furnace, 37…Flow path wall, 40…Preheating calcination section, 42…Rising duct, 44…Calcination furnace, 50…Cement kiln, 52…Kiln end, 54…Burner, 56…Kiln body, 60…Clinker cooler, 70…Cooling section, 72…Recovery section, 74…Suction section, 90…Chlorine bypass facility, 100…Cement clinker manufacturing apparatus, C1, C2, C3, C4…Cyclones, P…Central axis, SF…Swirling flow.

Claims

[Claim 1] an extraction step of extracting kiln exhaust gas generated when cement raw materials are burned in a cement kiln to obtain extracted gas; a classification step of separating coarse particles of the raw material dust from a mixed gas obtained by joining the extracted gas with an exhaust gas generated in a combustion furnace to obtain an output gas containing fine particles of the raw material dust, A method for operating a chlorine bypass system, comprising: combining the extracted gas, which has a temperature lower than that of the extracted gas in the extraction step, with the exhaust gas, which has a temperature higher than that of the extracted gas, to obtain the mixed gas.

Images