JP2022129625A - Chlorine bypass facility and operating method therefor, cement clinker manufacturing apparatus, and cement clinker manufacturing method - Google Patents

Abstract

To provide a chlorine bypass facility which can be stably operated.SOLUTION: A chlorine bypass facility 90 comprises: an extraction port 21A for extracting kiln exhaust gas from a kiln bottom 52 of a cement kiln 50, a rising duct 42, or between them; and a classification section 22 for separating coarse dust of raw material dust from mixed gas obtained by merging the extracted gas extracted from the extraction port 21A and the exhaust gas generated in a combustion furnace 32 to obtain derived gas containing fine powder of the raw material dust. The mixed gas is obtained by merging extracted gas having a temperature lower than that of gas extracted through the extraction port 21A with exhausted gas having a temperature higher than that of the extraction gas.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present disclosure relates to a chlorine bypass facility and its operating method, a cement clinker production apparatus, and a cement clinker production method.

Efforts are being made to use various wastes as raw materials and fuels in cement clinker manufacturing equipment. Under these circumstances, the amount of chlorine brought into cement kilns tends to increase. Chlorine bypass equipment is installed in many cement clinker manufacturing equipment to reduce chlorine in the cement kiln, and technology to efficiently remove chlorine from the gas extracted by this chlorine bypass equipment has been studied. there is In Patent Document 1, a technique of separating coarse powder from the extracted gas while maintaining the temperature of the extracted gas extracted from the kiln exhaust gas channel at 770° C. or higher, and then cooling it to 600° C. or lower to separate the chlorine bypass dust. is proposed.

Chlorine sources brought into cement kilns include waste plastics contained in the waste. Such waste plastics are used not only for the production of cement clinker, but also for the production of solid fuels, for example. For example, Patent Literature 2 proposes a technique of producing a solid fuel by heating a mixture containing powder obtained from coal and a thermoplastic such as polyvinyl chloride. In such a technique, when a pyrolysis gas obtained by heating 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 scrubber.

Japanese Patent Application Laid-Open No. 2019-55900 JP 2011-57750 A

In Patent Document 1, the temperature of the bled gas after separating the coarse powder of the dust is set to 770 ° C. or higher, and the volatilized chlorine content such as KCl and NaCl is precipitated alone in the classifier, or these are the raw material dust. It suppresses deposition on the surface. However, even if the gas bleed port to the classifier is insulated, the temperature of the bleed gas cannot be avoided as it passes through the flow path, and it may be difficult to maintain the above temperature. When the temperature of the gas that has passed through the classifier is less than 770°C, volatilized chlorine such as KCl and NaCl precipitates alone in the classifier, or precipitates on the surface of the raw material dust, resulting in chlorine bypass dust ( clinker dust). The clinker dust immediately after the chlorine precipitates on the surface or the clinker dust immediately after the chlorine precipitates alone has a very high adhesiveness, and there is concern that it will adhere to the inside of the classification section and cause coating. be. In addition, there is a concern that volatilized chlorine will precipitate in the classifying section, and raw material dust will adhere to it, resulting in coating. As described above, when the temperature in the classifying section drops, there is concern that it may cause operational fluctuations in the chlorine bypass facility and the cement clinker manufacturing apparatus.

Therefore, the present disclosure provides a chlorine bypass facility that can be stably operated and a method for operating the same. In addition, the present disclosure provides a cement clinker manufacturing apparatus and a cement clinker manufacturing method capable of stably manufacturing cement clinker by providing such a chlorine bypass facility.

The chlorine bypass facility according to one aspect of the present disclosure includes a bleed port for bleeding kiln exhaust gas from the kiln bottom of the cement kiln, a rising duct, or between them, a bleed gas bled from the bleed port, and an exhaust gas generated in a combustion furnace. a classifying section for separating coarse powder of the raw material dust from the mixed gas obtained by joining the above to obtain a derived gas containing fine powder of the raw material dust, wherein the bleed air has a lower temperature than when the air is bleed at the bleed port The mixed gas is obtained by combining the gas with the exhaust gas having a temperature higher than that of the extracted gas.

In the chlorine bypass facility, the bleed gas bled from the bleed port and the exhaust gas generated in the combustion furnace are combined with the bleed gas to obtain a mixed gas. At this time, the temperature of the bleed gas, which is bled from the bleed port, is lowered by passing through, for example, the flow path. Therefore, the bleed gas having a lower temperature than when it was bled at the bleed port is combined with the combustion furnace exhaust gas having a higher temperature to obtain a mixed gas. Since the high-temperature exhaust gas is merged in this manner, the temperature of the mixed gas and the derived gas can be stably increased. For this reason, in the classification section, in a state where chlorine is contained in the gas phase, the coarse powder of raw material dust contained in the bleed gas is separated from the mixed gas, and the coarse powder of raw material dust is separated from the bleed 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 washing facility can be reduced. Further, it is possible to prevent the chlorine from depositing alone in the classifying section or on the surface of the raw material dust to form clinker dust, which adheres to and clogs the interior of the classifying section. As a result, the chlorine bypass facility described above can be stably operated. In addition, since the coarse powder of the raw material dust separated in the classifying section 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.

It is preferable that the gas discharged from the classifying section of the chlorine bypass facility has a temperature of 770° C. or higher. This can sufficiently prevent the volatilized chlorine components such as KCl and NaCl from precipitating alone or precipitating on the surface of raw material dust to form clinker dust. Moreover, even when the raw material dust coarse powder is returned to the cement kiln, it is possible to reduce the introduction of chlorine into the cement kiln.

The combustion furnace burns pyrolysis gas generated by heat-treating the plastic, and the exhaust gas preferably contains chlorine. The pyrolysis gas includes, for example, tar. The gas discharged from the classifier contains coarse powder and fine powder of raw material dust that has not been collected by the classifier. The Ca content contained in the raw material dust that was not collected in this classifying section and the chlorine content such as HCl contained in the exhaust gas obtained by burning the pyrolysis gas reacted to form solid CaCl ₂ , which is also clinker dust. be able to collect. Therefore, it is possible to reduce the load on the cleaning device for treating exhaust gas from the combustion furnace containing chlorine. Further, if the entire amount of the exhaust gas from the combustion furnace containing chlorine is combined with the extraction gas, it is possible to omit the cleaning device for the exhaust gas.

It is preferable that the chlorine bypass facility includes a cooling gas introduction section for introducing the cooling gas so as to generate a swirling flow along the inner wall surface of the flow path through which the derived gas flows. As the temperature of the derived gas containing fine powder of the raw material dust and volatilized chlorine is lowered, the chlorine is precipitated or the chlorine is precipitated on the surface of the fine powder of the raw material dust to form clinker dust. The clinker dust immediately after the chlorine is deposited on the surface has a very high adhesiveness, and there is concern that it will adhere to the inner wall surface of the flow path and cause coating. In addition, there is a concern that volatilized chlorine will precipitate on the inner wall surface of the flow path, and raw material dust will adhere to the inner wall surface, resulting in coating.

For this reason, a cooling gas introduction part is provided for introducing the cooling gas so as to generate a swirling flow along the wall surface of the flow path of the derived gas. Such a cooling gas introduction part can protect the inner wall surface from the high-temperature outgoing gas by introducing the cooling gas so as to generate a swirling flow along the inner wall surface. Then, the high-temperature lead-out gas mainly flows through the central portion of the flow path. Therefore, the flow paths of the derived gas and the cooling gas are different in the flow path. Although a small amount of clinker dust is formed at the boundary between the outflow gas flow path and the cooling gas flow path, the swirling flow along the inner wall surface of the flow path functions as an air curtain, and the clinker dust adheres to the inner wall surface of the flow path. Coaching can be suppressed. Therefore, the chlorine bypass facility can be operated more stably. The "gas containing the derived gas" in the present disclosure is exemplified by the derived gas before being mixed with the cooling gas, and the gas obtained by mixing the derived gas and the cooling gas. However, gases other than these may be included.

It is preferable to include a recovery section for recovering clinker dust contained in the gas containing the derived gas obtained by cooling the derived gas, and a suction section for sucking the gas containing the derived gas downstream of the recovery section. . In the recovery section, the clinker dust can be recovered by suction by the suction section. Since the coarse powder of the raw material dust is reduced in the classifying section, the amount of clinker dust can be reduced, and the cost of washing the clinker dust with water can be reduced.

It is preferable that the chlorine bypass facility has a circulation passage for returning the coarse powder of raw material dust separated in the classifying section to the cement kiln side. While the temperature of the mixed gas is maintained at 770° C. or higher, 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. It can be effectively used as a raw material for cement clinker.

A cement clinker manufacturing apparatus according to one aspect of the present disclosure includes any of the chlorine bypass facilities described above. Therefore, since the chlorine bypass facility can be stably operated, the cement clinker manufacturing apparatus provided with the chlorine bypass facility can stably manufacture cement clinker.

A cement clinker manufacturing method according to one aspect of the present disclosure manufactures cement clinker using the cement clinker manufacturing apparatus. Therefore, cement clinker can be stably produced.

A method of operating a chlorine bypass facility according to one aspect of the present disclosure includes a extraction step of extracting kiln exhaust gas generated when cement raw materials are fired in a cement kiln to obtain extraction gas, and an extraction step of extracting extraction gas and exhaust gas generated in a combustion furnace. and a classification step of separating coarse powder of the raw material dust from the mixed gas obtained by joining the and to obtain a derived gas containing fine powder of the raw material dust, and having a temperature lower than that when the gas is extracted in the gas bleed step. The mixed gas is obtained by combining the bleed gas and the exhaust gas having a temperature higher than that of the bleed gas.

In the above operation method, the gas extracted in the gas extraction process and the exhaust gas generated in the combustion furnace are combined to obtain a mixed gas. At this time, the temperature of the bleed gas, which has been bleed in the bleed process, decreases, for example, by passing through the flow path. Therefore, since the exhaust gas having a higher temperature than the extracted gas having a lower temperature than that extracted in the extraction process is combined with the exhaust gas having a higher temperature than the extracted gas, the temperature of the mixed gas can be stably increased. For this reason, in the classification process, the coarse powder of the raw material dust is separated from the mixed gas in a state where the chlorine content is contained in the gas phase, and the coarse powder of the raw material dust is reduced more than the extracted gas and the mixed gas. You can get gas. As a result, it is possible to suppress an increase in the amount of clinker dust and reduce the load on the clinker dust washing equipment. In addition, since it is possible to suppress the precipitation of chlorine in the classification process, it is possible to suppress the occurrence of coating in the equipment. Due to these factors, the operating method described above can stably operate the chlorine bypass facility.

It is preferable to maintain the temperature of the mixed gas at 770° C. or higher in the classification step. As a result, if 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 channel, the chlorine content is in a volatilized state, so the raw material dust can be effectively used as a cement clinker raw material. can be done.

The operating method has a preheating step of preheating, using the exhaust gas, a classifying section for separating coarse powder of the raw material dust from the mixed gas to obtain a derived gas containing fine powder of the raw material dust before starting the classifying step. is preferred. By having such a preheating step, it is possible to suppress the generation of clinker dust in the classifying section from the beginning of use of the classifying section, where chlorine is precipitated alone or precipitated on the surface of raw material dust.

The above operation method includes a cooling gas introduction step of introducing a cooling gas so as to generate a swirl flow in a flow path through which the derived gas obtained by separating the coarse powder of the raw material dust from the mixed gas flows, and the derived gas and the cooling gas. and a dust recovery step of recovering clinker dust contained in the gas containing and. By providing the cooling gas introduction step, it is possible to prevent the clinker dust from adhering to the inner wall surface of the flow path due to the swirling flow in the flow path forming an air curtain. Therefore, clinker dust can be stably recovered by the dust recovery step.

It is possible to provide a chlorine bypass facility that can be stably operated and a method for operating the same. Moreover, by providing such a chlorine bypass facility, it is possible to provide a cement clinker manufacturing apparatus and a cement clinker manufacturing method capable of stably manufacturing cement clinker.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the chlorine bypass installation which concerns on one Embodiment, and a cement clinker manufacturing apparatus provided with the same. FIG. 4 is a cross-sectional view showing a radial cross-section of an outgoing gas flow path to which a cooling gas introduction part is connected;

An embodiment of the present disclosure will be described below with reference to the drawings as the case may be. However, the following embodiments are examples for explaining the present disclosure, and are not intended to limit the present disclosure to the following contents. In the description, the same reference numerals are used for the same elements or elements having the same function, and overlapping descriptions are omitted in some cases. In addition, unless otherwise specified, positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings. Furthermore, the dimensional ratio of each element is not limited to the illustrated ratio.

Drawing 1 is a figure showing chlorine bypass equipment concerning one embodiment, and a cement clinker manufacturing device provided with the same. The chlorine bypass facility 90 is connected to the rising duct 42 of the preheating and calcining section 40 of the cement clinker manufacturing apparatus 100 . The chlorine bypass facility 90 recovers volatile matter such as chlorine in the cement clinker manufacturing apparatus 100 as clinker dust to reduce the chlorine content in the cement clinker manufacturing apparatus 100 .

The chlorine bypass facility 90 includes a bleed port 21A that bleeds gas from the rising duct 42, a bleed pipe 21 through which the bleed gas containing raw material dust, which is bled from the bleed port 21A, flows, and the bleed gas and the combustion furnace 32. A classifying section 22 that joins with the exhaust gas to obtain a mixed gas, separates coarse powder of raw material dust from the mixed gas, and obtains an outlet containing fine powder of raw material dust smaller than the coarse powder, and a flow through which the outlet gas flows. A passage 24 and a cooling gas introduction section 10 for introducing a cooling gas so as to generate a swirling flow in the passage 24 .

The bleed gas bled from the bleed port 21A contains raw material dust and gaseous chlorine. Bleed gas flows through the bleed pipe 21 and is introduced into the classifier 22 . Bleed pipe 21 may be referred to as a bleed probe. The temperature of the bleed gas when it is introduced into the classifying section 22 is such that volatilized chlorine such as KCl and NaCl precipitates alone or precipitates on the surface of raw material dust and adheres to the classifying section 22 as clinker dust. From the viewpoint of suppression, the temperature is preferably higher than 770°C, more preferably 820°C or higher, and even more preferably 860°C or higher.

The bleed gas and the exhaust gas generated in the combustion furnace 32 are introduced into the classifying section 22, and the two are mixed in the classifying section 22 to obtain a mixed gas containing the bleed gas and the exhaust gas. The combustion furnace 32 is a furnace for burning tar contained in pyrolysis gas generated by heat-treating raw materials containing waste plastics in the desalting furnace 35 of the waste plastics desalting facility 30 . 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, exhaust gas from the combustion furnace having a higher temperature than the bleed gas whose temperature has been lowered by flowing through the bleed pipe 21 is introduced. As a result, the temperature of the mixed gas (derived gas) in the classifying section 22 can be stably increased. Therefore, in the classifying section 22, coarse particles of the raw material dust can be separated from the mixed gas in a state where chlorine is contained in the gas phase. Therefore, it is possible to suppress the clogging of the classifying section 22 due to coating caused by deposition of volatilized chlorine alone or deposition on the surface of raw material dust. In addition, it is possible to suppress the return of raw material dust containing chlorine to the cement kiln through the circulation passage.

By joining 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 of the classifying section 22 can be improved, and the coarse particles of the raw material dust can be separated from the mixed gas with higher accuracy. Classifying section 22 may be, for example, a cyclone. The particle size of the raw material dust coarse powder may be, for example, 18 μm or more, preferably 16 μm or more, and more preferably 14 μm or more. By classifying the raw material dust so that the coarse powder is 14 μm or more, the volatile matter can be sufficiently reduced.

The coarse powder of the raw material dust separated from the mixed gas in the classifying section 22 is used as a raw material for cement clinker. be introduced. In this way, by returning the coarse powder of the raw material dust bled from the air bleed port 21A to the bottom of the kiln 52, the coarse powder of the raw material dust can be used for manufacturing cement clinker. Coarse raw material dust may be returned to the rising duct 42 , the calcining furnace 44 , or the kiln main body 56 instead of the kiln bottom 52 . Alternatively, a plurality of circulation channels 27 may be provided to return the coarse powder of raw material dust to a plurality of locations. From the viewpoint of suppressing the precipitation of chlorine content in the coarse powder of the raw material dust separated from the mixed gas in the classifying unit 22, the temperature of the mixed gas when separating the coarse powder of the raw material dust in the classifying unit 22 is preferably It is preferably 770° C. or higher, more preferably 820° C. or higher, still more preferably 860° C. or higher. The temperature of the gas discharged from the classifying section 22 is also preferably 770° C. or higher, more preferably 820° C. or higher, and even more preferably 860° C. or higher.

The exhaust gas generated in the combustion furnace 32, flowing through the flow path 33, and joining the extraction gas at the classification section 22 or its inlet may contain chlorine such as HCl. The derived gas derived from the classifying section 22 contains coarse powder and fine powder of the raw material dust that has not been collected by the classifying section 22 . The Ca content contained in the raw material dust not recovered in the classifying unit 22 reacts with the chlorine content such as HCl contained in the exhaust gas generated in the combustion furnace 32 to form solid CaCl ₂ , and such chlorine content is also , can be recovered as clinker dust in the chlorine bypass plant 90 . Therefore, the load on the washing device in the waste plastic desalting equipment 30 can be reduced. Further, by introducing the entire amount of chlorine-containing exhaust gas generated in the combustion furnace 32 into the chlorine bypass facility 90, the operation of the cleaning device in the waste plastic desalination facility 30 can be omitted.

The exhaust gas that joins 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 desalination facility 30, but is the exhaust gas from a combustion furnace different from the combustion furnace 32 of the waste plastic desalination facility 30. may be Alternatively, exhaust gas containing no chlorine may be used. For example, it may be hot exhaust gas from a combustion furnace, an ammonia gasification furnace, a sulfur combustion furnace, or a combustion furnace or melting furnace different from these, which is provided in a biomass pellet carbonization facility. One of these exhaust gases may be used alone, or a plurality of exhaust gases may be used in combination.

The flow rate of the exhaust gas joining the extraction gas may be adjusted according to the operating conditions of the cement clinker production apparatus 100 or the chlorine bypass facility 90 . The flow rate of the exhaust gas is adjusted by, for example, the extraction gas flow path 24, the classification unit 22, the extraction pipe 21, the rising duct 42, the measurement unit that measures the operation information of the cement kiln 50 (kiln bottom 52), and/or the recovery This may be done based on the chlorine concentration of the clinker dust recovered in section 72 . Specifically, even if the operator manually adjusts the flow rate of the exhaust gas based on the operating information (eg temperature) of the classifier 22 and/or the chlorine concentration of the clinker dust recovered by the recovery unit 72, Better, it may be adjusted automatically using the control unit.

The operating information measured by the measurement unit includes temperature, pressure, components of the extracted gas, flow velocity of the extracted gas, dust concentration, images, and the like. Specifically, the temperature inside or on the surface of the extraction pipe 21, the classifying section 22, and the flow path 24, the temperature of the kiln exhaust gas at the rising duct 42 and the bottom of the kiln 52, and the temperature of the kiln exhaust gas flowing into the extraction pipe 21 from the extraction port 21A. The temperature, the pressure of the kiln exhaust gas and the extraction gas, the gas components of the kiln exhaust gas and the extraction gas, the dust concentration contained in the kiln exhaust gas and the extraction gas, and the images inside the extraction pipe 21 and the classifying section 22, and the like. Examples of the measuring unit include a temperature sensor, a pressure sensor, a gas component sensor, a flow velocity sensor, a camera, and the like.

The chlorine bypass facility 90 may include a control section that outputs a control signal for adjusting the flow rate of exhaust gas based on the operational information measured by the measurement section. 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), an input/output interface, and the like.

By providing the controller, 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 classifying unit 22 may be measured by the measuring unit, and when the temperature T1 is below the lower limit, control may be performed so that the flow rate of the exhaust gas joining the extracted gas increases. . As a result, it is possible to prevent the temperature of the classifying section 22 from dropping too much.

The derived gas containing fine powder of raw material dust and gaseous chlorine, which is obtained by separating coarse powder of raw material dust from the mixed gas in the classifying unit 22, flows through the flow path 24 connected to the classifying unit 22 and is cooled. It is cooled in the gas introduction part 10 . In the cooling gas introduction part 10, the flow path of the cooling gas 11 is connected to the flow path 24 composed of the circular pipe 26, and the derived gas containing the raw material dust fine powder and chlorine is mixed with the cooling gas and cooled. After cooling, the gas including the derived gas flows through the flow path 24 and is introduced into the cooling section 70 .

In the cooling gas introduction part 10, the cooling gas 11 is introduced so as to follow the circumferential direction of the inner wall surface of the flow path 24 through which the lead-out gas containing fine powder of raw material dust and chlorine content flows. As a result, a swirl flow is generated in the flow path 24, and it is possible to suppress the occurrence of coating due to adhesion of clinker dust to the inner wall surface of the flow path 24. Such a swirling flow forms an air curtain around the outer periphery of the flow path 24, and can protect the inner wall surface of the circular tube 26 forming the flow path 24 from the high-temperature lead-out gas.

In the cooling gas introduction part 10, the derived gas is mixed with the cooling gas 11 and cooled. The temperature of the gas containing the derived gas after cooling (mixed gas of the derived gas and the cooling gas) may be 600° C. or lower, or 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 include exhaust gas generated in a factory or the like at a temperature of 200° C. or less, preferably 100° C. or less. Exhaust gas includes, for example, odorous gas generated during reception, storage and fermentation of water-containing sludge such as sewage sludge brought into a cement manufacturing plant, exhaust gas discharged from the later-described suction unit 74 and suction units in other processes, and the like. is mentioned. These 1 type can be used individually or in combination of 2 or more types.

FIG. 2 is a cross-sectional view showing a radial cross-section of the lead-out gas flow path 24 to which the cooling gas introduction part is connected. A circular pipe 26 constitutes a channel 24 through which the raw material dust coarse powder is separated and the lead-out gas containing chlorine and raw material dust fine powder flows. When viewed in a radial cross section of the flow channel 24 (circular pipe 26) as shown in FIG. It is connected to the circular tube 26 . The cooling gas introduction part 10 connected to the circular pipe 26 introduces into the flow path 24 the cooling gas 11 flowing through the flow path 12 defined by the flow path wall 37 . The introduced cooling gas 11 forms a swirl flow SF while joining with the derived gas in the flow path 24 . The swirl axis of the swirl flow SF coincides with the central axis P of the flow path 24 formed by the circular pipe 26 .

The derived gas circulates in the central portion of the flow path 24 along the axial direction of the central axis P, and the cooling gas 11 circulates along the inner wall surface 26W of the circular tube 26 forming the flow path 24 as a swirling flow SF. In this way, in the flow path 24, the gases are circulated such that the flow paths of the derived gas and the cooling gas are different. Although a small amount of clinker dust is generated at the boundary between the flow path for the derived gas and the flow path for the cooling gas, the swirling flow SF serves as an air curtain, which prevents the clinker dust from adhering to the inner wall surface 26W and causing coating. can.

As shown in FIG. 1, the chlorine bypass facility 90 includes a cooling section 70 that cools the gas containing the derived gas downstream of the cooling gas introduction section 10, and the dust (clinker dust) contained in the gas containing the derived gas. and a suction unit 74 for sucking the derived gas. Cooling section 70 may be a water-cooled or air-cooled heat exchanger. The suction unit 74 includes a normal suction fan such as a sirocco fan and a turbo fan.

The cooling unit 70 cools the gas containing the derived gas obtained by joining the cooling gas 11 and the derived gas to, for example, less than 260°C, preferably less than 200°C. Since the gas containing this derived gas contains clinker dust, it is introduced into the recovery section 72 . The collection 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 mixed with a cement composition after being washed with water, or may be used as a raw material for cement.

The cement clinker manufacturing apparatus 100 of FIG. 1 includes a chlorine bypass facility 90, a preheating and calcining section 40 for preheating and calcining the cement raw material, and a cement kiln 50 for obtaining cement clinker by calcining the preheated and calcined cement raw material. and a clinker cooler 60 for cooling the cement clinker obtained in the cement kiln 50. - 特許庁The preheating and calcining section 40 has four cyclones C 1 , C 2 , C 3 , and C 4 (preheaters) and a calcining furnace 44 .

The kiln bottom 52 of the cement kiln 50 and the calcining furnace 44 of the preheating and calcining section 40 are connected by a rising duct 42 . In the vicinity of the connecting portion between the rising duct 42 and the kiln bottom 52, there is provided an air extraction port 21A of a chlorine bypass facility 90 for extracting kiln exhaust gas generated in the cement kiln 50 and recovering dust contained in the kiln exhaust gas. An air extraction pipe 21 is connected to the air extraction port 21A. The cement clinker manufacturing apparatus 100 can reduce the chlorine content in the cement clinker manufacturing apparatus 100 by including the chlorine bypass facility 90 .

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

Since the cement clinker production apparatus 100 includes the chlorine bypass facility 90, it can be operated stably, and cement clinker can be produced stably. In addition, the raw material dust can be effectively used to increase the yield of cement clinker. In addition, clinker dust is reduced, and the cost of treating clinker dust can be reduced.

Although the air bleed port 21A is provided in the rising duct 42 in this embodiment, it is not limited to this. For example, in a modification, the air bleed port 21A may be provided at the kiln bottom 52, or may be provided between (or at the boundary of) the kiln bottom 52 and the rising duct . Further, in the present embodiment, the exhaust gas generated from the combustion furnace 32 joins with the extraction gas in the classifying section 22, but it is not limited to this. In a modified example, the extraction gas and the exhaust gas may join together to form a mixed gas between the classification section 22 and the extraction port 21A, for example, in the flow path within the extraction pipe 21 . In this case, by connecting the flue gas passage 33 and the extraction pipe 21 , the confluence of the extraction gas and the exhaust gas can be provided upstream of the classification section 22 . Here, the term “upstream” refers to the positional relationship between the confluence portion and the classification portion 22 based on the flow direction of the extraction gas (mixed gas). Since the mixed gas obtained by merging the extracted gas and the exhaust gas has a sufficiently high temperature, deposition of chlorine is suppressed, and deposition and clogging of the coating in the classifying section 22 can be suppressed. In another modification, the exhaust gas flow path 33 may be branched so that the exhaust gas is divided into a plurality of locations and joined with the extraction gas or mixed gas. In this case, a control unit may be provided that individually adjusts the flow rate of the exhaust gas joining at the plurality of joining portions.

A cement clinker manufacturing method according to one embodiment can be performed using a cement clinker manufacturing apparatus 100 . These methods include a preheating and calcining step of preheating and calcining the cement raw material in the preheating and calcining unit 40, and introducing the preheated and calcined cement raw material from the kiln bottom 52 into the kiln body 56 to manufacture cement clinker. a sintering process, a bleed process for obtaining a bleed gas by extracting the kiln exhaust gas generated in the sintering process, a merging process for joining the bleed gas containing the raw material dust and the exhaust gas generated in the combustion furnace, and the bleed gas and the exhaust gas. A classification step in which coarse powder of raw material dust is separated in the classifying unit 22 from the mixed gas obtained by joining the A cooling gas introduction step of introducing the cooling gas so as to generate a swirling flow, a cooling step of cooling the gas containing the derived gas, and a dust recovery of recovering clinker dust contained in the gas containing the derived gas cooled in the cooling step. and a step. A circulation step of returning coarse powder of the raw material dust separated in the classification step to the cement kiln 50 side may also be provided. In addition, a clinker cooling step may be included in which the cement clinker obtained in the firing step is cooled by the clinker cooler 60 .

In the preheating and calcining step, the raw material for cement is introduced from the channel between the cyclones C1 and C2. The raw material for cement is preheated through cyclones C1, C2 and C3. After that, it is introduced into the calcining furnace 44 and calcined. The calcining furnace 44 may be provided with a burner for burning fuel such as coal. The cement raw material (calcined raw material) calcined in the calcining furnace 44 is introduced into the cyclone C4 and heated.

In the firing process, the calcined raw material heated by the cyclone C4 is introduced into the bottom 52 of the kiln. After that, it is fired in the kiln body 56 to become a cement clinker. In the air extraction process, the kiln exhaust gas generated in the firing process is extracted from the air extraction port 21A. In the merging step, the bleed gas, which has been bled from the bleed port and passed through the flow passage and whose temperature has been lowered, is joined with the exhaust gas of the combustion furnace having a higher temperature than the bleed gas. This makes it possible to stably increase the temperature of the mixed gas in the classification process. Therefore, in the classification step, the coarse powder of the raw material dust can be separated from the mixed gas in a state in which chlorine is contained in the gaseous phase in the mixed gas. Therefore, it is possible to suppress the clogging of the classifying section 22 due to coating caused by deposition of volatilized chlorine alone or deposition on the surface of raw material dust. In addition, it is possible to suppress the return of the raw material dust in which chlorine is deposited to the cement kiln side through the circulation flow path.

The merging process and the classifying process may be performed together in the classifying section 22, or after the merging process is performed in the merging section provided in the extraction pipe 21 to obtain a mixed gas, the mixed gas is processed in the classifying section 22. A classification step of separating coarse particles of raw material dust may be performed. By carrying out the circulation process of returning coarse powder of raw material dust obtained in the classification process to the kiln bottom 52 of the cement kiln 50, the cement clinker production amount can be efficiently increased.

When the classification process is started, if the extraction gas passes through the extraction pipe 21 and the classification section 22 that are not warmed up, there is a concern that clinker dust will adhere to the inner wall surface of the flow path. Therefore, a preheating step of preheating the insides of the bleed pipe 21 and the classification section 22 using the exhaust gas generated from the combustion furnace 32 may be performed. Preheating locations include the air extraction pipe 21 forming a flow path from the air extraction port 21A where the refractory is constructed to the classifying section 22 and the classifying section 22 . When the draft of the suction unit 74 is used for preheating, a damper is provided near the air extraction port 21A so as not to suck the kiln exhaust gas containing volatilized chlorine, which is extracted from the air extraction port 21A. It is preferable to introduce the exhaust gas generated in the combustion furnace 32 from a point close to the . When using the draft of the SP fan for preheating, it is preferable to provide a damper at the gas outlet of the classifying section 22 to introduce the high-temperature exhaust gas into the classifying section 22 . Moreover, from the viewpoint of suppressing the deposition 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.

In the cooling gas introduction step, the cooling gas is joined 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 passage 24 containing the derived gas, which is formed by the circular pipe 26 . As a result, it is possible to suppress the occurrence of coating due to adhesion of clinker dust to the flow path 24 . The temperature of the gas containing the derived gas cooled by mixing the cooling gas 11 in the cooling gas introduction step may be 600° C. or less, or 500° C. or less from the viewpoint of the heat resistance of the equipment. By cooling the derived gas in this way, the volatilized chlorine is precipitated alone or on the surface of the raw material dust to form clinker dust.

In the cooling step, the gas including the derived gas is cooled to, for example, less than 260°C, preferably less than 200°C, in a cooling section 70 including a heat exchanger, for example. In the dust collecting step, the dust contained in the gas containing the derived gas cooled in the collecting unit 72 is collected. The dust collected in this way is called clinker dust. This manufacturing method allows the chlorine bypass facility 90 and the cement clinker manufacturing apparatus 100 to be stably operated. Moreover, the raw material dust can be effectively used to efficiently produce cement clinker. In addition, the amount of clinker dust is reduced by separating the coarse powder of the raw material dust in the classification step, and the processing cost of the clinker dust can be reduced.

A method for operating a chlorine bypass facility according to one embodiment may include the above-described extraction step, confluence step, classification step, cooling step, and dust recovery step. Moreover, it may have the above-mentioned circulation process, and may further have any one of the steps of the above-described cement clinker manufacturing method. This operating method can be performed using a chlorine bypass facility 90 provided in the cement clinker manufacturing apparatus 100 . Therefore, the contents of each step may be the same as those in the cement clinker manufacturing method described above.

The contents of the description of the chlorine bypass facility 90 and the cement clinker manufacturing apparatus 100 described above also apply to the description of the method of manufacturing the cement clinker and the operating method of the chlorine bypass facility described above. Moreover, the description of the manufacturing method and the operating method described above also applies to the description of the chlorine bypass facility 90 and the cement clinker manufacturing apparatus 100 described above.

Although several embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments. For example, in the above-described embodiment, coarse powder of raw material dust separated by the classifying section 22 is returned to the cement kiln 50 side through the circulation flow path 27, but the present invention is not limited to this. For example, it may be put in a cement raw material tank and supplied to the preheating and calcining section 40 as a cement raw material. Further, the circular pipe 26 forming the flow path 24 of the derived gas may not be arranged horizontally, but may be inclined with respect to the horizontal direction. The chlorine bypass facility may have a mixing chamber between the cooling gas introduction section 10 and the cooling section 70 .

ADVANTAGE OF THE INVENTION According to this indication, the chlorine bypass installation which can be operate|moved stably and its operating method are provided. Moreover, a cement clinker production apparatus and a cement clinker production method capable of stably producing cement clinker by providing such a chlorine bypass facility are provided.

DESCRIPTION OF SYMBOLS 10... Cooling gas introduction part 11... Cooling gas, 12, 24, 33... Flow path, 21... Bleeding pipe, 21A... Bleeding port, 22... Classification part, 26... Circular pipe, 26W... Inner wall surface, 27... Circulating flow Path 30 Waste plastic desalting facility 32 Combustion furnace 35 Desalting furnace 37 Channel wall 40 Preheating and calcining unit 42 Rising duct 44 calcining furnace 50 Cement kiln 52 ... kiln bottom, 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 device, C1, C2 , C3, C4... Cyclone, P... Central axis, SF... Swirling flow.

Claims (9)

a bleed port for bleed kiln exhaust gas from the kiln end of the cement kiln, the rising duct, or between these;
a classifier for obtaining a derived gas containing fine powder of raw material dust by separating coarse powder of raw material dust from a mixed gas obtained by joining the bleed gas bled from the bleed port and the exhaust gas generated in the combustion furnace; with
A chlorine bypass facility for obtaining the mixed gas by combining the bleed gas having a temperature lower than that of the bleed gas and the exhaust gas having a temperature higher than that of the bleed gas. 2. The chlorine bypass facility according to claim 1, wherein said outlet gas discharged from said classifier has a temperature of 770[deg.] C. or higher. The combustion furnace burns pyrolysis gas generated by heat-treating the plastic,
3. The chlorine bypass facility according to claim 1 or 2, wherein the exhaust gas contains chlorine. 4. The chlorine bypass facility according to any one of claims 1 to 3, further comprising a cooling gas introduction unit for introducing cooling gas so as to generate a swirling flow along the inner wall surface of the flow path through which the derived gas flows. A cement clinker manufacturing apparatus comprising the chlorine bypass facility according to any one of claims 1 to 4. A cement clinker manufacturing method for manufacturing cement clinker using the cement clinker manufacturing apparatus according to claim 5 . a bleed process for obtaining bleed gas by bleed kiln exhaust gas generated when cement raw materials are fired in a cement kiln;
a classification step of separating coarse powder of raw material dust from a mixed gas obtained by joining the extracted gas and exhaust gas generated in the combustion furnace to obtain a derived gas containing fine powder of the raw material dust;
A method of operating a chlorine bypass facility, wherein the bleed gas having a lower temperature than the bleed gas in the bleed process and the exhaust gas having a higher temperature than the bleed gas are combined to obtain the mixed gas. 8. The method according to claim 7, further comprising a preheating step of using the exhaust gas to preheat, before starting the classifying step, a classifying section that separates the coarse powder from the mixed gas to obtain the derived gas containing the fine powder. method of operating the chlorine bypass facility. a cooling gas introduction step of introducing the cooling gas so as to generate a swirling flow in the passage through which the derived gas flows;
9. The method of operating a chlorine bypass facility according to claim 7, further comprising a dust recovery step of recovering dust contained in the gas containing the derived gas and the cooling gas.

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