Chlorine bypass equipment, cement clinker manufacturing apparatus, cement clinker manufacturing method, and operation method of chlorine bypass equipment

Abstract

To suppress occurrence of coating accompanied by cooling of extracted gas.SOLUTION: A chlorine bypass facility includes: an extraction port for extracting a part of exhaust gas from a cement kiln for baking a cement raw material; and a cyclone for cooling which is configured to separate powder from introduction gas derived from extraction gas extracted from the extraction port while swirling the introduction gas, and cools the introduction gas. The cyclone for cooling has: a first gas introduction port for introducing the introduction gas into a body part formed with a swirl flow of the introduction gas; a second gas introduction port for introducing gas for cooling with lower temperature than the introduction gas into the body part so as to swirl outside the swirl flow of the introduction gas; and a gas discharge port for discharging gas obtained by mixing the introduction gas and the gas for cooling from the body part.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a chlorine bypass facility, an apparatus for producing cement clinker, a method for producing cement clinker, and a method for operating a chlorine bypass facility. [Background Art]

[0002] In apparatuses for producing cement clinker, efforts are underway to use various types of waste as raw materials and fuel. Under these circumstances, the amount of chlorine brought into cement kilns tends to increase. Many cement clinker production 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. Patent Document 1 proposes a technology in which coarse powder is separated from the extracted gas extracted from a kiln exhaust gas channel while maintaining the temperature of the extracted gas at 770° C or higher, and then the temperature is cooled to 600° C or lower to separate chlorine bypass dust. [Prior Art Literature] [Patent Literature]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. 2019-55900 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] The present disclosure provides a chlorine bypass facility, an apparatus for producing cement clinker, a method for producing cement clinker, and a method for operating a chlorine bypass facility that are useful for suppressing the occurrence of coating accompanying cooling of extracted gas. [Means for Solving the Problem]

[0005] [1] A chlorine bypass system comprising: an extraction port for extracting a portion of the exhaust gas from a cement kiln for firing cement raw materials; and a cooling cyclone configured to separate powder from the introduced gas while swirling the introduced gas derived from the extracted gas extracted from the extraction port, wherein the cooling cyclone has a first gas inlet for introducing the introduced gas into a main body where a swirling flow of the introduced gas is formed; a second gas inlet for introducing a cooling gas at a lower temperature than the introduced gas into the main body so as to swirl outside the swirling flow of the introduced gas; and a gas outlet for discharging a gas obtained by mixing the introduced gas and the cooling gas from the main body.

[0006] [2] The chlorine bypass equipment according to [1] above, further comprising a classification cyclone that maintains the temperature of the extracted gas at 770°C or higher, separates coarse raw material dust contained in the extracted gas from the extracted gas to produce a classified gas containing fine raw material dust, and the classified gas is introduced into the cooling cyclone as the introduction gas.

[0007] [3] The chlorine bypass equipment according to [1] or [2] above, wherein the first gas inlet and the second gas inlet introduce gas to the main body from angles that coincide with each other, and the cooling cyclone is positioned at the boundary between a portion that guides the introduced gas introduced from the first gas inlet and a portion that guides the cooling gas introduced from the second gas inlet, and further has a heating portion that heats the boundary portion.

[0008] [4] The chlorine bypass equipment according to [1] or [2] above, wherein the first gas inlet and the second gas inlet introduce gas to the main body from different angles to each other.

[0009] [5] The chlorine bypass equipment according to [4] above, wherein the cooling cyclone further has a heating section that heats the portion of the outer wall of the portion that guides the introduced gas introduced from the first gas inlet, which is opposite to the portion that guides the cooling gas introduced from the second gas inlet.

[0010] [6] The chlorine bypass equipment according to any one of [1] to [5] above, wherein the cooling cyclone further has a heating section that heats at least a portion of the outer wall of the main body.

[0011] [7] The heating unit heats at least a portion of the outer wall of the main body by circulating a heating gas, which is hotter than the cooling gas, along the outer wall of the main body, and the heating unit circulates the heating gas in the opposite direction to the introduced gas and the cooling gas, as described in [6] above.

[0012] [8] A cement clinker manufacturing apparatus comprising the chlorine bypass equipment described in any one of [1] to [7] above, and the cement kiln.

[0013] [9] A method for producing cement clinker, comprising producing cement clinker using the manufacturing apparatus described in [8] above.

[0014]

[10] A method for operating a chlorine bypass facility, comprising: an extraction step to obtain extracted gas by extracting a portion of the exhaust gas from a cement kiln for firing cement raw materials; and a cooling step to cool an introduced gas derived from the extracted gas using a cooling cyclone configured to separate powder from the introduced gas while swirling the introduced gas, wherein the cooling step comprises: a first introduction step of introducing the introduced gas to the main body of the cooling cyclone so as to form a swirling flow of the introduced gas in the main body of the cooling cyclone; a second introduction step of introducing a cooling gas at a lower temperature than the introduced gas to the main body so as to swirl outside the swirling flow of the introduced gas; and a discharge step of discharging a gas obtained by mixing the introduced gas and the cooling gas from the main body. [Effects of the Invention]

[0015] According to the present disclosure, there are provided a chlorine bypass facility useful for suppressing the occurrence of coating accompanying the cooling of extracted gas, an apparatus for manufacturing cement clinker, a method for manufacturing cement clinker, and an operation method for a chlorine bypass facility. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] [Figure 1] FIG. 1 is a schematic diagram showing an example of an apparatus for manufacturing cement clinker. [Figure 2] FIG. 2 is a schematic diagram showing an example of the system configuration of a chlorine bypass facility. [Figure 3] FIG. 3 is a side view schematically showing an example of a cooling cyclone. [Figure 4] FIG. 4 is a top view schematically showing an example of a cooling cyclone. [Figure 5] FIG. 5 is a top view schematically showing an example of a cooling cyclone. [Figure 6] FIG. 6 is a side view schematically showing an example of a cooling cyclone. [Figure 7] FIG. 7 is a top view schematically showing an example of a cooling cyclone. [Figure 8] FIG. 8 is a top view schematically showing an example of a cooling cyclone. [Figure 9] FIG. 9 is a side view schematically showing an example of a cooling cyclone. [Figure 10] FIG. 10 is a side view schematically showing an example of a cooling cyclone. [Figure 11] FIG. 11 is a top view schematically showing an example of a cooling cyclone. [Figure 12] FIG. 12(a) and FIG. 12(b) are side views schematically showing an example of a cooling cyclone. [Figure 13] FIG. 13(a) and FIG. 13(b) are side views schematically showing an example of a cooling cyclone. DESCRIPTION OF EMBODIMENTS

[0017] Hereinafter, embodiments will be described with reference to the drawings. 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 duplicate descriptions are omitted in some cases. The dimensional ratio of each element is not limited to the ratio shown in the drawings. An XYZ orthogonal coordinate system is shown in some drawings. In the following description, the Z-axis corresponds to the vertical direction, and the X-axis and Y-axis correspond to the horizontal direction.

[0018] [Apparatus for manufacturing cement clinker] FIG. 1 schematically shows an apparatus for manufacturing cement clinker according to an embodiment. The manufacturing apparatus 1 (apparatus for manufacturing cement clinker) shown in FIG. 1 is an apparatus that calcines cement raw materials to manufacture cement clinker. The manufacturing apparatus 1 includes a preheater 10, a cement kiln 20, a clinker cooler 30, and a chlorine bypass facility 50.

[0019] The preheater 10 is an apparatus that preheats cement raw materials. In addition to preheating the cement raw materials, the preheater 10 may also calcine the cement raw materials. The preheater 10 includes, for example, cyclones C1, C2, C3, C4 and a calciner 12. In the preheater 10, exhaust gas from the cement kiln 20 (hereinafter referred to as "kiln exhaust gas") flows through the calciner 12, cyclone C4, cyclone C3, cyclone C2, and cyclone C1. In the preheater 10, cement raw material is introduced into the connection between cyclone C1 and cyclone C2.

[0020] The cement raw material introduced into the preheater 10 is heated by heat exchange with kiln exhaust gas, etc., as it flows through cyclones C1, C2, C3, calcination furnace 12, and cyclone C4, and is then introduced into the kiln end 22 of the cement kiln 20. The preheater 10 has a rising duct 14 that connects the kiln end 22 of the cement kiln 20 to the calcination furnace 12. Kiln exhaust gas is introduced into the calcination furnace 12 via the rising duct 14. The kiln exhaust gas includes combustion exhaust gas from the cement kiln 20. In addition to the kiln exhaust gas, thermal energy raw material is introduced into the calcination furnace 12, and the calcination furnace 12 calcines the cement raw material.

[0021] The cement kiln 20 is a device that produces cement clinker by firing cement raw materials. The cement kiln 20 may fire cement raw materials that have been preheated and calcined in the preheater 10. The cement kiln 20 has a burner 24 and a main body 26. The burner 24 is located at the end of the main body 26 opposite to the kiln tail 22. The main body 26 is formed in a cylindrical shape and is rotatable around its central axis. The cement kiln 20 is also called a rotary kiln.

[0022] Inside the main body 26, the cement raw materials are fired by the combustion of the burner 24. The cement kiln 20 discharges the cement clinker obtained from the cement raw materials into the clinker cooler 30. The clinker cooler 30 is a device for cooling the cement clinker. After being cooled by the clinker cooler 30, the cement clinker is discharged from the manufacturing apparatus 1.

[0023] (Chlorine bypass equipment) The chlorine bypass equipment 50 is a device that extracts a portion of the kiln exhaust gas generated in the cement kiln 20 and recovers volatile components such as chlorine in the manufacturing apparatus 1 as dust. By installing the chlorine bypass equipment 50 in the manufacturing apparatus 1, the chlorine content in the manufacturing apparatus 1 can be reduced. The chlorine bypass equipment 50 is connected, for example, to the rising duct 14. In this case, the chlorine bypass equipment 50 extracts the kiln exhaust gas from the rising duct 14.

[0024] Figure 2 schematically shows an example of the system configuration of the chlorine bypass equipment 50. The chlorine bypass equipment 50 includes, for example, an extraction port 52, a duct 54, a first cyclone 60, a duct 62, a second cyclone 70, a duct 98, a recovery unit 92, a suction unit 94, and a dust processing unit 96. In the following description, the terms "upstream" and "downstream" will be used based on the gas flow. The gas immediately after extraction in the chlorine bypass equipment 50 (gas that has not undergone any treatment after extraction) will be referred to as "gas G1".

[0025] The extraction port 52 is an opening for extracting a portion of the kiln exhaust gas. The extraction port 52 may be provided in the rising duct 14. Alternatively, the extraction port 52 may be provided at the kiln end 22, either in place of or in addition to the rising duct 14, or between the kiln end 22 and the rising duct 14 (the boundary portion). The duct 54 has an extraction port 52 formed at one end and is a pipe that allows the gas G1 (extracted gas) obtained by extracting from the extraction port 52 to flow to the first cyclone 60. The duct 54 is also called an extraction probe.

[0026] Gas G1 contains raw material dust and volatile chlorine components such as KCl and NaCl. The raw material dust contained in gas G1 includes coarse powder and fine powder with a smaller particle size than the coarse powder. Gas G1 has a temperature of 770°C or higher. The temperature of gas G1 may be around 1000°C to 1100°C. Gas G1 flows through duct 54 and is introduced into the first cyclone 60.

[0027] The first cyclone 60 (classification cyclone) is a device that maintains the temperature of gas G1 at 770°C or higher, separates the coarse particles of raw material dust contained in gas G1, and generates a gas containing fine particles of raw material dust (classified gas). Hereinafter, the gas after the coarse particles of raw material dust have been separated in the first cyclone 60 (the gas generated by the first cyclone 60) will be referred to as "gas G2".

[0028] The particle size of the coarse raw material dust may be 18 μm or larger. Preferably, the particle size of the coarse raw material dust may be 16 μm or larger, and more preferably 14 μm or larger. The particle size of the fine raw material dust is smaller than the particle size of the coarse raw material dust described above. The chlorine concentration of the raw material dust (clinker dust) varies depending on the particle size, with the coarse raw material dust having a lower chlorine concentration than the fine raw material dust. Therefore, by separating the coarse raw material dust with a low chlorine concentration in the first cyclone 60 and returning the separated coarse raw material dust to the cement kiln 20, it is possible to reduce the amount of chlorine introduced into the cement kiln 20 while suppressing the increase in the amount of dust that needs to be processed in the chlorine bypass equipment 50.

[0029] From the viewpoint of suppressing the precipitation of volatile chlorine components such as KCl and NaCl on the surface of the coarse raw material dust separated from gas G1 in the first cyclone 60, the temperature of gas G1 when separating the coarse raw material dust in the first cyclone 60 is preferably maintained at 820°C or higher, more preferably at 860°C or higher. It is preferable that gas G2 at the outlet of the first cyclone 60 has the above temperature. Since gas G2 has a sufficiently high temperature, chlorine components such as KCl and NaCl are contained in the gas phase within gas G2.

[0030] As shown in Figure 1, the chlorine bypass equipment 50 is equipped with a circulation line 58. The circulation line 58 is a device that transports the coarse raw material dust separated from the first cyclone 60 to the kiln end 22 of the cement kiln 20 and returns it to the kiln end 22. By returning the coarse raw material dust extracted from the extraction port 52 to the kiln end 22, the coarse raw material dust contained in the gas G1 can be used in the production of cement clinker. In addition to or instead of returning the coarse raw material dust to the kiln end 22, the circulation line 58 may also return the coarse raw material dust to one or more of the rising duct 14, the calcination furnace 12, and the main body 26 of the cement kiln 20.

[0031] Returning to Figure 2, duct 62 is a pipe that carries gas G2 obtained from the first cyclone 60 to the second cyclone 70. Gas G2 has a temperature of 770°C or higher. Gas G2 is derived from the extracted gas (gas G1) obtained by extracting kiln exhaust gas at the extraction port 52. Gas G2 flows through duct 62 and is introduced into the second cyclone 70.

[0032] The second cyclone 70 (cooling cyclone) is a device configured to separate powder from the introduced gas while swirling the gas. The second cyclone 70 has the function of cooling gas G2 using cooling gas Gc. Gas G2 and cooling gas Gc are introduced into the second cyclone 70, and the second cyclone 70 mixes gas G2 and cooling gas Gc to produce a gas that is at a lower temperature than gas G2. Hereinafter, the gas produced in the second cyclone 70 that is at a lower temperature than gas G2 will be referred to as "gas G3". The temperature of gas G3 produced in the second cyclone 70 (gas after cooling in the second cyclone 70) is, for example, less than 260°C, preferably less than 200°C. Details of the second cyclone 70 will be described later.

[0033] Duct 98 is a pipe that circulates gas G3 from the second cyclone 70 to the recovery unit 92. Gas G3 is introduced into the recovery unit 92 from duct 98. The recovery unit 92 is a device that recovers clinker dust (chlorine bypass dust) contained in gas G3 from gas G3. The recovery unit 92 may be a bag filter or a wet dust collector such as a wet scrubber. Suction unit 94 sucks in gas G3. Suction unit 94 may be a normal suction fan such as a sirocco fan or a turbo fan.

[0034] The dust processing unit 96 is a device that performs a water washing treatment on the clinker dust obtained by the recovery unit 92. The clinker dust after the water washing treatment in the dust processing unit 96 may be blended into the cement composition or used as a cement raw material.

[0035] (Cooling cyclone) Figure 3 schematically shows a side view of the second cyclone 70, and Figure 4 schematically shows a top view of the second cyclone 70. Figure 3 shows a side view of the second cyclone 70 from the outside, with the gas flow inside indicated by arrows. Figure 4 shows a cross-section when cut through a horizontal plane passing through the gas inlet. The second cyclone 70 is configured to separate powder from the gas while swirling the gas G2 from top to bottom.

[0036] In addition to gas G2, a cooling gas Gc is introduced into the second cyclone 70. The second cyclone 70 has the function of separating fine raw material dust from gas G2 while swirling gas G2 and cooling gas Gc, and the function of lowering the temperature of gas G2 by mixing gas G2 and cooling gas Gc. The second cyclone 70 discharges gas G3, obtained by mixing gas G2 and cooling gas Gc, into the duct 98. As shown in Figures 3 and 4, the second cyclone 70 has a main body 71, a gas inlet 72, a gas inlet 74, a powder outlet 78, and a gas outlet 82.

[0037] The main body 71 is the main body portion of the cyclone and is the part that forms a swirling gas flow in the space inside it. The main body 71 may be formed to extend along a vertical axis Ax1. Ax1 is a hypothetical line that extends in the vertical direction. The main body 71 can be divided into two parts, for example, an upper and a lower part. The upper part of the main body 71 is formed in a cylindrical shape with a substantially constant diameter, except for the gas introduction portion, and the lower part of the main body 71 is formed in a truncated cone shape with a diameter that narrows towards the bottom. In the cross-section of the main body 71 when cut by a plane perpendicular to the axis Ax1, the peripheral walls constituting the main body 71 extend around the axis Ax1.

[0038] The second cyclone 70 circulates gas G2 and cooling gas Gc from top to bottom within the main body 71. At this time, the second cyclone 70 circulates gas G2 and cooling gas Gc along the peripheral wall of the main body 71 while swirling them around the axis Ax1. Swirling flows of gas G2 and cooling gas Gc are formed inside the main body 71. Furthermore, the second cyclone 70 mixes gas G2 and cooling gas Gc at the lower end of the main body 71 (the lower end and its vicinity), and then causes the mixed gas to rise through the central part through which the axis Ax1 passes. From the viewpoint of suppressing the formation of coating caused by the condensation of chlorine contained in gas G2, a cylindrical member for guiding the mixed gas does not need to be provided in the central part of the main body 71.

[0039] The gas inlet 72 (first gas inlet) is an opening for introducing gas G2 into the main body 71. The gas inlet 72 is formed so that gas G2 is introduced into the upper part of the main body 71 and the direction of introduction of gas G2 is horizontal. The gas inlet 74 (second gas inlet) is an opening for introducing cooling gas Gc into the main body 71. The cooling gas Gc may be air at room temperature, or it may be a gas containing exhaust gas generated in a factory or the like. The gas inlet 74 is formed so that cooling gas Gc is introduced into the upper part of the main body 71 and the direction of introduction of cooling gas Gc is horizontal.

[0040] The gas inlet 74 introduces the cooling gas Gc into the main body 71 such that the cooling gas Gc swirls outside the swirling flow of gas G2. The swirling flow of the cooling gas Gc forms an air curtain between the swirling flow of gas G1 and the inner surface (inner wall) of the peripheral wall of the main body 71, which suppresses the condensation of chlorine on the inner wall due to the high temperature gas G2 coming into contact with and being cooled by the inner wall of the main body 71.

[0041] Gas inlets 72 and 74 introduce gas into the main body 71 from angles that coincide with each other. That is, the direction of introduction of gas G2 from gas inlet 72 and the direction of introduction of cooling gas Gc from gas inlet 74 may coincide with each other. The angle at which gas G2 is introduced (the direction of introduction of gas G2 from gas inlet 72) is defined by the angle (direction) of a line perpendicular to gas inlet 72. The angle at which cooling gas Gc is introduced (the direction of introduction of cooling gas Gc from gas inlet 74) is defined by the angle (direction) of a line perpendicular to gas inlet 74. Note that the angles coincide includes cases where the angles are substantially the same.

[0042] The main body 71 includes a guide section 71a at its upper part, which guides the gas introduced from the gas inlet to the cylindrical section. The guide section 71a forms a flow path with a rectangular cross-section, for example, and adjusts the gas flow so that a swirling flow of gas is formed in the main body 71 (excluding the guide section 71a). The flow path within the guide section 71a is divided into two regions by a guide plate 75. As a result, the flow path within the guide section 71a is divided into a region through which gas G2 flows and a region through which cooling gas Gc flows.

[0043] An opening for introducing gas is provided at the end of the guide section 71a, and this opening is divided by one end of the guide plate 75 into gas inlets 72 and 74, which are arranged side by side. In the guide section 71a, the area through which gas G2 introduced from gas inlet 72 flows is located closer to the axis Ax1 than the area through which cooling gas Gc introduced from gas inlet 74 flows.

[0044] The powder discharge port 78 is located at the lower end of the main body 71 and is an opening for discharging fine raw material dust separated from the gas G2. The fine raw material dust discharged from the powder discharge port 78 contains chlorine. The fine raw material dust discharged from the powder discharge port 78 may be returned to the kiln end 22 of the cement kiln 20 via the circulation line 58. Alternatively, the fine raw material dust discharged from the powder discharge port 78 may be processed in the dust processing unit 96 instead of being returned to the kiln end 22.

[0045] The gas outlet 82 is located at the upper end of the main body 71 and is an opening through which gas G3, obtained by mixing gas G2 and cooling gas Gc, is discharged from the main body 71. The upstream end of the duct 98 is connected to the gas outlet 82, and the gas G3 discharged from the gas outlet 82 to the outside of the main body 71 is introduced into the duct 98.

[0046] In the second cyclone 70, when viewed from above, the cooling gas Gc introduced from the gas inlet 74 rotates once around the axis Ax1 before overlapping with the part of the guide section 71a through which gas G2 flows (see the part indicated by "A" in Figure 4). However, since the cooling gas Gc flows downward while rotating in the main body 71, it is possible to suppress the decrease in temperature of the wall portion forming the part of the guide section 71a through which gas G2 flows, due to the cooling gas Gc. Furthermore, after the gas G2 reaches the lower end of the main body 71, as it rises towards the gas outlet 82, all or most of the gas G2 can mix with the cooling gas Gc, so condensation of chlorine due to mixing with the cooling gas Gc is less likely to occur on the inner wall of the main body 71.

[0047] [Method for manufacturing cement clinker] Next, as an example of a method for manufacturing cement clinker, the manufacturing process of cement clinker carried out in manufacturing apparatus 1 will be described. The manufacturing process carried out in manufacturing apparatus 1 includes, for example, a preheating and calcination process, a firing process, a clinker cooling process, and a recovery process. These processes are carried out for periods that overlap at least partially. The preheating and calcination process is a process in which cement raw materials are preheated and calcined in a preheater 10 using high-temperature gas, including kiln exhaust gas from the cement kiln 20.

[0048] The firing process is a process in which the cement raw materials are fired in the cement kiln 20 using combustion gas from the burner 24. The clinker cooling process is a process in which the cement clinker produced in the cement kiln 20 is cooled in the clinker cooler 30. The recovery process is a process in which a portion of the kiln exhaust gas is extracted in the chlorine bypass equipment 50 and volatile components such as chlorine in the manufacturing apparatus 1 are recovered as dust. Since the chlorine bypass equipment 50 is operated during the recovery process, the recovery process is also a method of operating the chlorine bypass equipment.

[0049] (Operation method for chlorine bypass equipment) The method for operating the chlorine bypass equipment 50 (method of operating the chlorine bypass equipment) includes an extraction process, a classification process, a gas cooling process (cooling process), a circulation process, and a processing process. The extraction process is a process in which a portion of the exhaust gas from the cement kiln 20 is extracted from the extraction port 52 to obtain gas G1, which is the extracted gas. The classification process is a process in which, using the first cyclone 60, which is a classification cyclone, the temperature of gas G1 is maintained at 770°C or higher, and coarse raw material dust contained in gas G1 is separated from gas G1 to produce gas G2.

[0050] The gas cooling process is a process of cooling gas G2 derived from gas G1 using a second cyclone 70, which is a cooling cyclone. The gas cooling process includes a first introduction process, a second introduction process, and a discharge process. The first introduction process is a process of introducing gas G2 into the main body 71 from a gas inlet 72 so that a swirling flow of gas G2 is formed. The second introduction process is a process of introducing cooling gas Gc, which is at a lower temperature than gas G2, into the main body 71 from a gas inlet 74 so that it swirls outside the swirling flow of gas G2. The discharge process is a process of discharging gas G3, obtained by mixing gas G2 and cooling gas Gc, from the main body 71 via a gas outlet 82.

[0051] The circulation process is a process in which the coarse powder of the raw material dust obtained in the classification process is returned to the cement kiln 20 via the circulation line 58. In the circulation process, the fine powder of the raw material dust obtained in the gas cooling process may also be returned to the cement kiln 20 via the circulation line 58. The processing process is a process in which clinker dust is recovered from gas G3 by the recovery unit 92 and the clinker dust is subjected to a water washing treatment.

[0052] [Modified form] The cooling cyclone described above is just one example and can be modified as appropriate. The chlorine bypass equipment 50 may be equipped with a second cyclone 70A (cooling cyclone) as shown in Figure 5 instead of the second cyclone 70. The second cyclone 70A differs from the second cyclone 70 in that the gas inlet 72 and the gas inlet 74 introduce gas to the main body 71 from different angles. In the second cyclone 70A, the angle at which gas G2 is introduced (the direction of introduction of gas G2 at the gas inlet 72) is different from the angle at which cooling gas Gc is introduced (the direction of introduction of cooling gas Gc at the gas inlet 74). That is, the angle (direction) of the line perpendicular to the gas inlet 72 is different from the angle (direction) of the line perpendicular to the gas inlet 74.

[0053] The main body 71 of the second cyclone 70A includes, at its upper part, a guide section 71b that guides the gas G2 introduced from the gas inlet 72 to the cylindrical part, and a guide section 71c that guides the cooling gas Gc introduced from the gas inlet 74 to the cylindrical part. A space S is formed between the guide section 71b and the guide section 71c. The formation of space S makes it difficult for the gas G2 flowing through the flow path of the guide section 71b to be cooled by the cooling gas Gc flowing through the flow path of the guide section 71c.

[0054] The chlorine bypass equipment 50 may be equipped with a second cyclone 70B (cooling cyclone) as shown in Figure 6 instead of the second cyclone 70. The second cyclone 70B differs from the second cyclone 70 in that it has a main body 71B instead of a main body 71. The main body 71B includes a linear motion section 77a and a conical section 77b. The linear motion section 77a corresponds to the upper part of the main body 71B and is formed in a cylindrical shape with a substantially constant diameter except for the gas introduction section. The conical section 77b corresponds to the lower part of the main body 71B and is formed in a truncated cone shape with a diameter that narrows towards the bottom.

[0055] The top plate portion 87a of the linear motion section 77a is formed in a spiral shape so as the rotation progresses around the axis Ax1, starting from the gas inlet. The second cyclone 70B is a so-called helical-top type cyclone. Because the spiral top plate portion 87a is formed at the top of the cyclone, the cooling gas Gc introduced from the gas inlet 74 is guided more downward than if the top plate portion 87a were not formed. Therefore, the cooling gas Gc introduced from the gas inlet 74 is less likely to affect the gas G2 (see also the portion indicated by A in Figure 4) just before it is introduced into the rotating section after completing one rotation.

[0056] The chlorine bypass equipment 50 may be equipped with a second cyclone 70C (cooling cyclone) as shown in Figure 7 instead of the second cyclone 70. The second cyclone 70C differs from the second cyclone 70 in that a guide plate 75C is provided instead of the guide plate 75. A heating section 84C is provided on the guide plate 75C. The heating section 84C is provided, for example, inside the guide plate 75C. The guide plate 75C corresponds to the boundary portion between the part that guides the gas G2 introduced from the gas inlet 72 and the part that guides the cooling gas Gc introduced from the gas inlet 74. The heating section 84C heats the boundary portion.

[0057] The heating section 84C may have a plurality of rod-shaped heaters. The plurality of rod-shaped heaters may be arranged at predetermined intervals along the extending direction of the guide plate 75C. By providing the heating section 84C on the guide plate 75C, a decrease in the temperature of the guide plate 75C due to the cooling gas Gc introduced from the gas inlet 74 is suppressed. In this case, the cooling of the gas G2 introduced from the gas inlet 72 due to the decrease in the temperature of the guide plate 75C is suppressed.

[0058] The chlorine bypass equipment 50 may be equipped with a second cyclone 70D (cooling cyclone) as shown in Figure 8 instead of the second cyclone 70. The second cyclone 70D differs from the second cyclone 70A in that it further has a heating section 84D. The heating section 84D is located in the space S between the guide section 71b and the guide section 71c. The heating section 84D heats the portion of the outer wall of the guide section 71b that faces the guide section 71c.

[0059] The heating section 84D may be provided on the outer wall of the guide section 71b, on the portion facing the guide section 71c. The heating section 84D may also be a panel-shaped heater. By heating the portion of the outer wall of the guide section 71b facing the guide section 71c, the decrease in the temperature of the outer wall of the guide section 71b caused by the cooling gas Gc introduced from the gas inlet 74 and flowing through the flow path of the guide section 71c is suppressed. In this case, the cooling of the gas G2 introduced from the gas inlet 72 and flowing through the flow path of the guide section 71b is suppressed due to the decrease in the temperature of the guide section 71b.

[0060] The chlorine bypass equipment 50 may be equipped with a second cyclone 70E (cooling cyclone) as shown in Figure 9 instead of the second cyclone 70. The second cyclone 70E differs from the second cyclone 70B in that it further has a heating section 84E. The heating section 84E heats at least a portion of the outer wall of the main body 71B. For example, the heating section 84E heats 1 / 3 or more of the entire main body 71B, including the lower end of the main body 71B, or 1 / 2 or more of the entire main body 71B.

[0061] The heating unit 84E may heat the outer wall of the cone portion 77b, which corresponds to the lower part of the main body portion 71B. The heating unit 84E may also be a panel heater. Inside the main body portion 71B, a swirling flow of cooling gas Gc is formed outside the swirling flow of gas G2, but there is a possibility that gas G2 may come into contact with the inner wall of the main body portion 71B in a part of the inner wall of the main body portion 71B. By providing the heating unit 84E, the cooling of gas G2 before it mixes with the cooling gas Gc is suppressed due to gas G2 coming into contact with the inner wall of the main body portion 71B.

[0062] The chlorine bypass equipment 50 may be equipped with a second cyclone 70F (cooling cyclone) as shown in Figures 10 and 11, instead of the second cyclone 70. The second cyclone 70F differs from the second cyclone 70E in that it has a heating unit 84F instead of the heating unit 84E. The heating unit 84F heats at least a portion of the outer wall of the main body 71B by circulating a heating gas Gh, which is at a higher temperature than the cooling gas Gc, along the outer wall of the main body 71B.

[0063] The heating unit 84F may circulate the heating gas Gh around the outer wall of the main body 71B so that it rotates upward around the axis Ax1. In this case, while gas G2 and cooling gas Gc move from top to bottom, the heating gas Gh moves from bottom to top. Thus, the heating unit 84F may circulate the heating gas Gh in the opposite direction to gas G2 and cooling gas Gc. In this case, since the temperature of gas G2 decreases further as it moves downward, the cooling of gas G2 before mixing with cooling gas Gc can be efficiently suppressed.

[0064] The chlorine bypass equipment 50 may be equipped with a second cyclone 70G (cooling cyclone) as shown in Figures 12(a) and 12(b) instead of the second cyclone 70. The second cyclone 70G introduces gas G2 and cooling gas Gc into the main body 71G from below through gas inlets 72 and 74. The gas inlets 72 and 74 of the second cyclone 70G are downward-facing openings.

[0065] The second cyclone 70G swirls gas G2 and cooling gas Gc around a horizontal axis Ax2 inside its main body 71G. Ax2 is a hypothetical line extending horizontally. Inside the main body 71G, the cooling gas Gc swirls outside the swirling flow of gas G2. In the second cyclone 70G, gas G3, which is a mixture of gas G2 and cooling gas Gc, is discharged from the gas outlet 82G, which is a horizontal opening through which axis Ax2 passes. In the second cyclone 70G, fine raw material dust is discharged from the powder outlet 78, which is a downward-facing opening.

[0066] The chlorine bypass equipment 50 may be equipped with a second cyclone 70H (cooling cyclone) as shown in Figure 13(a) instead of the second cyclone 70. The second cyclone 70H differs from the second cyclone 70G in that the gas inlet 72 and the gas inlet 74 introduce gas from different angles. The second cyclone 70H employs the same configuration as the second cyclone 70A shown in Figure 5 for the gas introduction section.

[0067] The chlorine bypass equipment 50 may be equipped with a second cyclone 70I (cooling cyclone) as shown in Figure 13(b) instead of the second cyclone 70. The second cyclone 70I differs from the second cyclone 70H in that it further has a heating section 84I that heats the outer wall of the main body 71G. The heating section 84I heats at least a portion of the outer wall of the main body 71G. The heating section 84I may be a panel-shaped heater, similar to the heating section 84E shown in Figure 9, and heating gas Gh may be circulated along the outer wall of the main body 71G, similar to the heating section 84F shown in Figures 10 and 11.

[0068] In the second cyclone 70 described above, gas G2, which is the extracted gas after classification in the first cyclone 60, was cooled. However, the second cyclone 70 may cool gas G1 instead of gas G2. In this case, gas G1 itself, which is the extracted gas, is introduced into the second cyclone 70 as the introduction gas derived from the extracted gas. Furthermore, the chlorine bypass equipment 50 does not necessarily have to be equipped with the first cyclone 60.

[0069] The second cyclone 70 may be configured in any way as long as it can cool the introduced gas (e.g., gas G2) by forming a swirling flow of cooling gas Gc outside the swirling flow of the introduced gas. In one of the various examples described above, at least some of the matters described in the other examples may be combined.

[0070] [Summary of this disclosure] The chlorine bypass equipment 50 described above includes an extraction port 52 for extracting a portion of the exhaust gas from the cement kiln 20 used for firing cement raw materials, and a cooling cyclone (70, 70A~70I) configured to separate powder from the introduced gas (G1, G2) while swirling the introduced gas (G1, G2) derived from the extracted gas extracted from the extraction port 52. The cooling cyclone (70, 70A~70I) has a gas inlet 72 for introducing the introduction gas (G1, G2) into the main body sections 71, 71B, 71G where a swirling flow of the introduction gas (G1, G2) is formed; a gas inlet 74 for introducing a cooling gas Gc, which is at a lower temperature than the introduction gas (G1, G2), into the main body sections 71, 71B, 71G so that it swirls outside the swirling flow of the introduction gas (G1, G2); and a gas outlet 82 for discharging the gas (G3) obtained by mixing the introduction gas (G1, G2) and the cooling gas Gc from the main body sections 71, 71B, 71G.

[0071] One possible method for cooling the gas derived from the extracted gas obtained by extracting exhaust gas from the cement kiln 20 is to introduce a cooling gas into the duct through which the gas flows. When this method is adopted, the part of the duct located upstream of the cooling gas introduction section constitutes a heat-insulating section, and the part located downstream of the heat-insulating section constitutes a cooling section. In this case, the temperature at the downstream end of the heat-insulating section decreases due to the cooling gas. When the temperature at the end decreases, the gas derived from the extracted gas is cooled at the end, and coating may occur due to the condensation of chlorine. In contrast, in the chlorine bypass equipment 50 described above, the introduced gases (G1, G2) derived from the extracted gas are cooled by mixing with the cooling gas Gc inside the cooling cyclone. Inside the cooling cyclone, as described above, the part that forms the flow path through which the introduced gases (G1, G2) circulate is not easily cooled by the cooling gas Gc. Therefore, the chlorine bypass equipment 50 is useful in suppressing the occurrence of coating associated with the cooling of the extracted gases (G1, G2).

[0072] The chlorine bypass equipment 50 described above further includes a classification cyclone (60) that maintains the temperature of the extracted gas (G1) at 770°C or higher, separates the coarse powder of the raw material dust contained in the extracted gas (G1) from the extracted gas (G1) to generate a classified gas containing the fine powder of the raw material dust. The classified gas may be introduced as the introduction gas (G2) into the cooling cyclones (70, 70A~70I). In this case, by returning the coarse powder of the raw material dust with a low chlorine concentration to the cement kiln 20, the amount of chlorine introduced into the cement kiln 20 can be reduced while suppressing an increase in the amount of dust that needs to be processed in the chlorine bypass equipment 50.

[0073] In the chlorine bypass equipment 50 described above, the gas inlets 72 and 74 introduce gas into the main body 71 from mutually coincidental angles, and the cooling cyclone (70C) is positioned at the boundary portion (75C) between the portion that guides the introduced gases (G1, G2) introduced from the gas inlet 72 and the portion that guides the cooling gas Gc introduced from the gas inlet 74, and may further have a heating portion 84C that heats the boundary portion (75C). In this case, the structure of the parts for introducing the two types of gases is simplified, and it is possible to suppress the decrease in the temperature of the introduced gases (G1, G2) introduced from the gas inlet 72 due to the cooling gas Gc introduced from the gas inlet 74 before they are mixed with the cooling gas Gc.

[0074] In the chlorine bypass equipment 50 described above, the gas inlet 72 and the gas inlet 74 may introduce gas into the main body 71 from different angles. In this case, it is possible to suppress the decrease in the temperature of the introduced gases (G1, G2) introduced from the gas inlet 72 before they are mixed with the cooling gas Gc introduced from the gas inlet 74.

[0075] In the chlorine bypass equipment 50 described above, the cooling cyclone (70D) may further have a heating section 84D that heats the portion of the outer wall of the section (71b) that guides the introduced gases (G1, G2) introduced from the gas inlet 72, which faces the section (71c) that guides the cooling gas Gc introduced from the gas inlet 74. In this case, it is possible to further suppress the decrease in the temperature of the introduced gases (G1, G2) introduced from the gas inlet 72 before they are mixed with the cooling gas Gc, due to the cooling gas Gc introduced from the gas inlet 74.

[0076] In the chlorine bypass equipment 50 described above, the cooling cyclones (70E, 70F, 70I) may further have heating sections 84E, 84F, 84I that heat at least a portion of the outer walls of the main body sections 71B, 71G. On the inner walls of the main body sections 71B, 71G, there is a possibility that the introduced gases (G1, G2) may come into localized contact with the inner walls of the main body sections 71B, 71G. In the above configuration, by providing the heating sections 84E, 84F, 84I, the introduction gases (G1, G2) are prevented from being cooled before mixing with the cooling gas Gc due to contact with the inner walls of the main body sections 71B, 71G.

[0077] In the chlorine bypass equipment 50 described above, the heating section 84F may heat at least a portion of the outer wall of the main body 71B by circulating a heating gas Gh, which is at a higher temperature than the cooling gas Gc, along the outer wall of the main body 71B. The heating section 84F may also circulate the heating gas Gh in the opposite direction to the introduced gases (G1, G2) and the cooling gas Gc. As the introduced gases (G1, G2) move through the cooling cyclone, their temperature decreases further, so the above configuration efficiently suppresses the cooling of the introduced gases (G1, G2) before mixing with the cooling gas Gc.

[0078] The manufacturing apparatus 1 described above comprises a chlorine bypass system 50 and a cement kiln 20. Because the manufacturing apparatus 1 is equipped with a chlorine bypass system 50, it is useful in suppressing the occurrence of coating associated with the cooling of the extracted gases (G1, G2).

[0079] The cement clinker manufacturing method described above uses manufacturing apparatus 1 to produce cement clinker. In this manufacturing method, manufacturing apparatus 1 equipped with a chlorine bypass facility 50 is used, which is useful in suppressing the occurrence of coating associated with the cooling of the extracted gases (G1, G2).

[0080] The operation method of the chlorine bypass equipment 50 described above includes an extraction step to obtain extracted gas by extracting a portion of the exhaust gas from the cement kiln 20 that burns cement raw materials, and a cooling step to cool the introduced gas (G1, G2) derived from the extracted gas using a cooling cyclone (70, 70A~70I) configured to separate powder from the gas while swirling the introduced gas, and the cooling step involves the introduction gas in the main body sections 71, 71B, 71G of the cooling cyclone (70, 70A~70I) The operating method includes a first introduction step of introducing introduction gas (G1, G2) to the main body sections 71, 71B, and 71G so as to form a swirling flow of gas (G1, G2); a second introduction step of introducing cooling gas Gc, which is at a lower temperature than the introduction gas (G1, G2), to the main body sections 71, 71B, and 71G so as to swirl outside the swirling flow of the introduction gas (G1, G2); and a discharge step of discharging gas (G3), which is obtained by mixing the introduction gas (G1, G2) and the cooling gas Gc, from the main body sections 71, 71B, and 71G. This operating method is useful for suppressing the occurrence of coating associated with the cooling of the extracted gas (G1, G2), similar to the chlorine bypass equipment 50 described above. [Explanation of symbols]

[0081] 1...Cement clinker manufacturing equipment, 10...Preheater, 12...Calibration furnace, 14...Rising duct, 20...Cement kiln, 50...Chlorine bypass equipment, 60...First cyclone, 70, 70A~70I...Second cyclone, 71, 71B, 71G...Main body, 71a, 71b, 71c...Guide section, 72, 74...Gas inlet, 75, 75C...Guide plate, 82, 82G...Gas outlet, 84C, 84D, 84E, 84F, 84I...Heating section, G1, G2, G3...Gas, Gc...Cooling gas, Gh...Heating gas.

Claims

1. An extraction port for extracting a portion of the exhaust gas from the cement kiln used to fire cement raw materials, The system is configured to separate powder from the introduced gas while swirling the introduced gas derived from the extracted gas extracted from the extraction port, and includes a cooling cyclone for cooling the introduced gas. The cooling cyclone is, The main body and A first gas inlet for introducing the introduced gas into the main body is provided so that a swirling flow of the introduced gas is formed around a predetermined axis in the main body, A second gas inlet introduces a cooling gas, which is at a lower temperature than the aforementioned introduced gas, into the main body such that it swirls around the axis in the same direction as the swirling flow of the introduced gas, and swirls outside the swirling flow of the introduced gas. A chlorine bypass device having a gas outlet for discharging a gas obtained by mixing the introduction gas and the cooling gas from the main body.

2. The system further comprises a classification cyclone that maintains the temperature of the extracted gas at 770°C or higher, separates the coarse powder of the raw material dust contained in the extracted gas from the extracted gas, and generates a classified gas containing the fine powder of the raw material dust. The chlorine bypass equipment according to claim 1, wherein the classified gas is introduced as the introduction gas into the cooling cyclone.

3. The first gas inlet and the second gas inlet introduce gas into the main body from angles that coincide with each other. The chlorine bypass equipment according to claim 1 or 2, wherein the cooling cyclone is positioned at the boundary between a portion that guides the introduced gas introduced from the first gas inlet and a portion that guides the cooling gas introduced from the second gas inlet, and further comprises a heating portion that heats the boundary portion.

4. The chlorine bypass equipment according to claim 1 or 2, wherein the first gas inlet and the second gas inlet introduce gas to the main body from different angles to each other.

5. The chlorine bypass equipment according to claim 4, wherein the cooling cyclone further has a heating section that heats the portion of the outer wall of the section that guides the introduced gas introduced from the first gas inlet, the portion that faces the section that guides the cooling gas introduced from the second gas inlet.

6. The chlorine bypass equipment according to claim 1 or 2, wherein the cooling cyclone further has a heating section that heats at least a portion of the outer wall of the main body.

7. The heating unit heats at least a portion of the outer wall of the main body by circulating a heating gas, which is at a higher temperature than the cooling gas, along the outer wall of the main body. The chlorine bypass equipment according to claim 6, wherein the heating section circulates the heating gas in the opposite direction to the introduction gas and the cooling gas.

8. A chlorine bypass system according to claim 1 or 2, A cement clinker manufacturing apparatus comprising the aforementioned cement kiln.

9. A method for producing cement clinker, comprising producing cement clinker using the manufacturing apparatus described in claim 8.

10. An extraction process to obtain extracted gas by extracting a portion of the exhaust gas from a cement kiln used to fire cement raw materials, The process includes a cooling step of cooling the introduced gas, which originates from the extracted gas, using a cooling cyclone configured to separate powder from the introduced gas while swirling the gas, The aforementioned cooling process is A first introduction step involves introducing the introduction gas into the main body of the cooling cyclone such that a swirling flow of the introduction gas is formed around a predetermined axis in the main body of the cooling cyclone, A second introduction step involves introducing a cooling gas, which is at a lower temperature than the introduced gas, into the main body such that it swirls around the axis in the same direction as the swirling flow of the introduced gas, and swirls outside the swirling flow of the introduced gas. A method for operating a chlorine bypass system, comprising a discharge step of discharging a gas obtained by mixing the introduction gas and the cooling gas from the main body.

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