JP6634818B2 - Bleeding device and bleeding method - Google Patents

Description

  The present disclosure relates to a bleed device and a bleed method.

Cement clinker (hereinafter, referred to as “clinker”) is usually manufactured through a process of firing a raw material in a kiln (rotating path) with a combustion gas such as pulverized coal having a maximum temperature of 2000 ° C. or more. In a kiln, the raw material is heated to about 1450 ° C. Therefore, even if the waste is used as a raw fuel, the organic matter contained in the waste is decomposed to a level of CO ₂ or H ₂ O which does not retain the properties of the original molecule. On the other hand, most of the inorganic substances contained in the waste are taken into the clinker and become almost harmless. Therefore, in recent years, a large amount of waste has been used as a raw material for cement.

  Kiln exhaust gas discharged from the kiln is usually at a high temperature of 900 ° C. or higher. Therefore, in order to improve energy efficiency, it is common to connect a suspension preheater (hereinafter, referred to as “SP”) to the kiln, preheat the raw material and put it into the kiln, thereby recovering heat from the kiln exhaust gas. It is being done. The SP exhaust gas discharged from the SP is also about 300 ° C. to 400 ° C. and is still at a high temperature, so that the heat is further recovered by drying the raw material and using a power generation boiler, etc. Discharge.

  By the way, in the clinker baking apparatus including the kiln and the SP, the gas flows in the system in a direction substantially opposite to the direction of the raw material supplied to the clinker baking apparatus. That is, the gas flow and the raw material flow are generally countercurrent. For this reason, components of the raw fuel that are likely to produce volatile substances (volatile components) are vaporized in the high-temperature kiln, but become low-melting compounds in the SP, which is at a lower temperature than the kiln, and re-enter the kiln. By returning, it can be circulated in the system (in the clinker firing device) and gradually concentrated. The concentrated components take a paste-like form and can adhere to the clinker firing device. Such deposits are sometimes referred to as coatings.

  When the coaching grows in the clinker firing device, the flow of raw materials and gas is hindered. However, as described above, with an increase in the amount of waste used as a raw fuel, chlorine, which is an element extremely easy to form a low-melting substance, is particularly increasing in a clinker firing apparatus. Chlorine binds to many metal atoms and becomes a molecule having a high saturated vapor pressure and relatively stable, so that it can be easily circulated in the system. Therefore, an increase in the amount of coaching is concerned.

  Therefore, Patent Documents 1 and 2 disclose a process of extracting components such as chlorides from a clinker firing device (a technique called “chlorine bypass”). Specifically, a part of the kiln exhaust gas is guided to a cooling chamber, and in the cooling chamber, the kiln exhaust gas is cooled by cooling air (Patent Document 1) or cooling water (Patent Document 2), thereby solidifying volatile components and Has been removed.

JP 09-175847 A JP 2014-014730 A

  When the volatile components are cooled in the cooling chamber, they become fumes and solidify. The fume is composed of fine particles having a particle size on the order of submicrons (less than 1 μm). Such fine particles or aggregated particles obtained by aggregating the fine particles (hereinafter, collectively referred to as “fine particles”) have a strong adhesive force, so that when the fine particles are collected in the filter, it is difficult to remove the fine particles from the filter. This can cause filter clogging (pressure loss). Further, the fine particles may adhere to the flow path of fine particles (for example, a dust collector, a bypass dust transport system) located downstream of the cooling chamber, and may block the fine particles. Therefore, when the chlorine bypass described in Patent Literatures 1 and 2 is performed, although the amount of generated coaching can be suppressed, filter replacement work or passage cleaning work frequently occurs, and the operation of the chlorine bypass is frequently interrupted. sell.

  Therefore, the present disclosure describes a bleeding apparatus and a bleeding method that can improve operation efficiency.

First, terms used in the present specification are defined as follows.
"Bleeding" refers to extracting gas from the clinker firing device.
“Extracted gas” refers to a gas extracted from a clinker firing device.
“Raw material dust” refers to a raw material accompanying the bleed gas.
The “bleeding device” refers to a device that cools a bleed gas and solidifies volatile components.
“Bypass dust” refers to dust that is collected together with the raw material dust in the bleeding device.
It should be noted that, in the present specification, the term “gas” includes not only the gas itself but also dust accompanying the gas.

  The bleeding device according to one aspect of the present disclosure includes a bleeding gas from a cement clinker firing device, and a cooler into which a cooling gas for cooling the bleeding gas is introduced, and water drops on the cooling gas before being introduced into the cooler. And a water supply device configured to accompany the water supply device.

  In the bleed device according to one aspect of the present disclosure, the water supply device is configured to cause water droplets to accompany the cooling gas before being introduced into the cooler. Therefore, the water droplet accompanying the cooling gas is gradually mixed with the extracted gas while moving along the flow of the cooling gas, so that the water droplet gradually cools the volatile component. Therefore, the volatile component can be gradually solidified into a seed crystal, and the crystal growth is effectively promoted. As a result, coarse particles having a relatively large particle size (that is, fine particles are coarsened) obtained by solidifying the volatile component are obtained, and the adhesive force of the coarse particles is weakened. As described above, clogging of the filter (pressure loss) and blockage of the flow path are suppressed, so that it is possible to improve the operation efficiency of the extraction device.

  The waterer may be configured to sprinkle the cooling gas. In this case, water droplets are more easily entrained along the cooling gas.

  The bleed device according to one aspect of the present disclosure may further include an auxiliary water supply configured to spray water into the cooler. In this case, when the bleed gas is directly cooled by water droplets sprinkled from the auxiliary water supply into the cooler, the volatile component forms a primary crystal and easily grows into a crystal of about several μm as it is. Further, when the raw material dust is cooled by the water droplets, the volatile component tends to aggregate on the surface of the raw material dust. As described above, coarse particles can be obtained more effectively.

  The bleed device according to one aspect of the present disclosure is a circulating flow configured to return to the cooler some of the particles that are discharged from the cooler and that accompany the mixed gas of the bleed gas and the cooling gas. A road may be further provided. That is, since the volatile components are cooled in the cooling chamber to generate fumes, some of the fine particles constituting the fumes are returned to the cooling chamber through the circulation channel. The fine particles come into contact with the bleed gas in the cooler and become seeds, and the volatile components solidify on the surface of the fine particles. Therefore, the volatile components in the extracted gas are prevented from becoming fumes alone, and the fine particles are coarsened. Therefore, the fine particles are coarsened and the adhesive force is weakened, so that clogging of the filter (pressure loss) and blockage of the flow path are suppressed. As a result, it is possible to improve the operation efficiency of the extraction device. In addition, since a part of the fine particles having a strong adhesive force is returned toward the cooler, the fine particles are suppressed from going downstream (toward the dust collector). Therefore, it is possible to further improve the operation efficiency of the extraction device. Further, since the pressure loss is reduced, the size of equipment such as a dust collector can be reduced.

  The bleed device according to one aspect of the present disclosure further includes a dust collector to which the mixed gas from the cooler is introduced and configured to collect dust contained in the mixed gas, and the circulation flow path includes a collecting channel. It may be configured to return a part of the dust collected by the dust container to the cooler.

  The circulation channel may be configured to return a part of the mixed gas to the cooler. In this case, the amount of gas directed to the dust collector is reduced, so that the size of equipment such as the dust collector can be further reduced.

  The water supply device may be configured to spray water into the circulation channel. Since the circulating gas has a higher temperature and a longer residence time than the cooling gas, when water is sprayed on the circulating flow path, water droplets volatilize before entering the cooler and have a small diameter. Therefore, water droplets having a relatively large diameter can be sprinkled into the circulation channel. The larger the diameter of the water droplet to be sprinkled, the smaller the energy required to generate the water droplet, which tends to require less energy.

  A bleeding method according to another aspect of the present disclosure includes a first step of introducing a bleed gas extracted from a cement clinker firing device into a cooler, and a step of causing water droplets to accompany the cooling gas before being introduced into the cooler. And a third step of introducing a cooling gas accompanied by water droplets into the cooler and cooling the extracted gas introduced into the cooler with the cooling gas.

  In the bleeding method according to another aspect of the present disclosure, in the second step, water droplets accompany the cooling gas before being introduced into the cooler. Therefore, the water droplet accompanying the cooling gas is gradually mixed with the extracted gas while moving along the flow of the cooling gas, so that the water droplet gradually cools the volatile component. Therefore, the volatile component can be gradually solidified into a seed crystal, and the crystal growth is effectively promoted. As a result, coarse particles having a relatively large particle size (that is, fine particles are coarsened) obtained by solidifying the volatile component are obtained, and the adhesive force of the coarse particles is weakened. As described above, clogging of the filter (pressure loss) and blockage of the flow path are suppressed, so that it is possible to improve the operation efficiency of the extraction device.

  In the second step, water droplets may be caused to accompany the cooling gas before being introduced into the cooler by spraying water on the cooling gas before being introduced into the cooler. In this case, water droplets are more easily entrained along the cooling gas.

  In the third step, a cooling gas accompanied by water droplets may be introduced into the cooler, and water may be sprayed into the cooler. In this case, when the bleed gas is directly cooled by water droplets sprinkled from the auxiliary water supply into the cooler, the volatile component forms a primary crystal and easily grows into a crystal of about several μm as it is. Further, when the raw material dust is cooled by the water droplets, the volatile component tends to aggregate on the surface of the raw material dust. As described above, coarse particles can be obtained more effectively.

  The bleeding method according to another aspect of the present disclosure further includes a fourth step of returning a part of the particles discharged from the cooler and accompanying the mixed gas of the bleed gas and the cooling gas to the cooler. May be. That is, in the cooling chamber, fumes are generated by cooling the volatile components, and a part of the fine particles constituting the fume is returned to the cooling chamber through the circulation flow path. The fine particles come into contact with the bleed gas in the cooler and become seeds, and the volatile components solidify on the surface of the fine particles. Therefore, the volatile components in the extracted gas are prevented from becoming fumes alone, and the fine particles are coarsened. Therefore, the fine particles are coarsened and the adhesive force is weakened, so that clogging of the filter (pressure loss) and blockage of the flow path are suppressed. As a result, it is possible to improve the operation efficiency of the extraction device. In addition, since a part of the fine particles having a strong adhesive force is returned toward the cooler, the fine particles are suppressed from going downstream (toward the dust collector). Therefore, it is possible to further improve the operation efficiency of the extraction device. Further, since the pressure loss is reduced, the size of equipment such as a dust collector can be reduced.

  In the fourth step, the mixed gas from the cooler is introduced into the dust collector to collect dust contained in the mixed gas, and a part of the dust collected by the dust collector is returned to the cooler. May be done.

  In the fourth step, a part of the mixed gas may be returned to the cooler. In this case, the amount of gas directed to the dust collector is reduced, so that the size of equipment such as the dust collector can be further reduced.

  In the fourth step, water droplets may be caused to accompany the cooling gas before being introduced into the cooler by spraying water on exhaust gas discharged from the cooler and before returning to the cooler. Since the circulating gas has a higher temperature and a longer residence time compared to the cooling gas, when water is sprayed on the exhaust gas discharged from the cooler and before returning to the cooler, water droplets volatilize before entering the cooler and have a small diameter. . Therefore, water droplets having a relatively large diameter can be sprayed on the exhaust gas discharged from the cooler and before returning to the cooler. The larger the diameter of the water droplet to be sprinkled, the smaller the energy required to generate the water droplet, which tends to require less energy.

  According to the extraction device and the extraction method according to the present disclosure, it is possible to improve the operation efficiency of the extraction device.

FIG. 1 is a schematic diagram illustrating an example (first example) of a clinker manufacturing apparatus according to the present embodiment. FIG. 2 is a schematic diagram illustrating another example (second example) of the clinker manufacturing apparatus according to the present embodiment. FIG. 3 is a schematic diagram illustrating another example (third example) of the clinker manufacturing apparatus according to the present embodiment. FIG. 4 is a schematic diagram illustrating another example (fourth example) of the clinker manufacturing apparatus according to the present embodiment. FIG. 5 is a schematic diagram illustrating another example (fifth example) of the clinker manufacturing apparatus according to the present embodiment. FIG. 6 is a diagram for explaining the definition of the apparent specific gravity.

  The embodiments according to the present disclosure described below are examples for describing the present invention, and therefore, the present invention should not be limited to the following contents. In the following description, the same elements or elements having the same functions will be denoted by the same reference symbols, without redundant description.

  The clinker manufacturing apparatus 1 is an apparatus for manufacturing the clinker M3 from the raw material M1. As shown in FIG. 1, the clinker manufacturing device 1 includes a clinker baking device 10 and a bleeding device 20.

  The clinker firing device 10 has a firing furnace 11 and an SP (suspension preheater) 12. The firing furnace 11 includes a kiln and a clinker cooler. The kiln is configured to bake the kiln raw material M2 introduced from SP12. The clinker cooler is configured to rapidly cool the kiln raw material M2 fired in the firing furnace 11 by heat exchange with a gas G1 such as air to generate a clinker M3. The temperature of the gas G1 introduced into the clinker cooler may be, for example, about room temperature. The gas G1 subjected to heat exchange in the clinker cooler is heated to, for example, about 500 ° C. to 1000 ° C., and is used for burning fuel (not shown) such as pulverized coal in the kiln. The maximum temperature of the combustion gases in the kiln is typically above 2000 ° C. The combustion gas burns the kiln raw material M2 and is discharged from the kiln as kiln exhaust gas G2. The temperature of the kiln exhaust gas G2 is usually about 900C to 1250C.

  SP12 is a device for preheating the raw material M1 in order to increase the firing efficiency of the kiln raw material M2 in the firing furnace 11. The SP 12 has a plurality of stages (for example, about four to five stages) of cyclones (separators). When the raw material M1 is introduced into the tower top of SP12, the kiln exhaust gas G2 and the raw material M1 introduced from the bottom of SP12 are sequentially heat-exchanged in each stage cyclone, and the raw material M1 is preheated to, for example, about 850 ° C. It becomes the raw material M2. The kiln raw material M2 generated in SP12 is discharged from the bottom of the tower and introduced into the firing furnace 11. On the other hand, the kiln exhaust gas G2 is discharged from the tower top of SP12 as SP exhaust gas G3 after heat exchange with the raw material M1. The temperature of the SP exhaust gas G3 is, for example, about 300 ° C. to 400 ° C. The heat of the SP exhaust gas G3 is further recovered by drying of the raw material, a power generation boiler, and the like, and the low-temperature recovered gas is discharged to the atmosphere. Note that the SP 12 may be a new suspension preheater (NSP) further including a calcining furnace provided between the lowermost stage of the cyclone and the firing furnace 11. In the NSP, a fuel (for example, pulverized coal) is supplied to a calciner to calcine the raw material M1, thereby increasing the production amount and the calcining efficiency of the clinker M3.

  In the clinker firing device 10, the gas flows in the system in a direction substantially opposite to the direction of the raw material M1 supplied to the clinker firing device 10 (SP12). Therefore, the volatile component is vaporized in the high-temperature kiln, but liquefies or solidifies in SP12, which is lower in temperature than the kiln, and returns to the kiln again to circulate in the clinker firing device 10. Coating may occur if volatile components are concentrated during this circulation. In recent years, as the amount of waste used as a raw fuel has increased, the content of chlorine, which is an element extremely easy to form a low-melting substance, has been particularly increasing, and there is a concern that the amount of generation of coating will increase.

  The bleeding device 20 is a device for performing a process of extracting components such as chlorides from the clinker firing device 10 (chlorine bypass). Specifically, the extraction device 20 extracts a part of the kiln exhaust gas G2 as extraction gas G4. Depending on the purpose of the bleeding by the bleeding device 20, the upper limit value (maximum capacity of the bleeding device 20) of the ratio (bleeding rate) of the bleed gas G4 to the kiln exhaust gas G2 becomes a value of more than 0% and 100% or less. The air extraction device 20 is installed in the clinker firing device 10. In the actual bleeding device 20, even if the bleeding device 20 is installed in the clinker firing device 10, the upper limit value of the bleeding rate (the maximum capacity of the bleeding device 20) becomes, for example, a value of 0.3% to 30%. Good. When stabilizing the operation of the clinker firing apparatus 10 by reducing the circulation of chlorides, the bleed apparatus 20 may be operated so that the bleed rate is less than 1%. When reducing the amount of chlorine or the like taken into the clinker M3, the bleed device 20 may be operated so that the bleed rate is 3% or more.

  The air extraction device 20 includes a cooler 21, a dust collector 22, and a water supply 23. The cooler 21 is configured to cool the bleed gas G4 from the clinker firing device 10. Cooler 21 includes a main duct that extracts and exhausts bleed gas G4, and a subduct into which cooling gas G5 is introduced. For example, the main duct is provided with an enlarged portion that is enlarged in the radial direction, and the sub duct is connected to the enlarged portion so as to extend in a tangential direction of an inner wall surface of the enlarged portion. The bleed gas G4 is introduced into the cooler 21 from the bottom of the tower, and the cooling gas G5 is introduced from the duct. The gas used as the cooling gas G5 is not particularly limited as long as it can cool the bleed gas G4, but may be, for example, air. The temperature of the cooling gas G5 introduced into the cooler 21 may be, for example, about room temperature.

In the cooler 21, the central part of the cooler 21 has a high temperature and the wall part has a low temperature, and the temperature distribution is considerably uneven. Therefore, in the cooler 21, the bleed gas G4 and the cooling gas G5 are not mixed very much. Therefore, the volatile components contained in the bleed gas G4 (the kiln exhaust gas G2) are prevented from reaching the inner wall surface, and hardly solidify on the inner wall surface of the cooler 21 (hardly adhere to the inner wall surface of the cooler 21). . Incidentally, in actual operation of the clinker production apparatus 1, the major volatile components in the extracted gas G4 is KCl and SO _2. The temperature at which they sufficiently solidify can be affected by various factors (eg, lowering of the melting point due to eutectic, heat of coagulation when gas liquefies and solidifies, heat of reaction during desulfurization, etc.), for example, about 600 ° C. It is. On the other hand, the bleed gas G4 and the cooling gas G5 are mixed in the cooler 21, and the solidification of the volatile component is promoted, so that fine particles or coarse particles obtained by coarsening the fine particles (to be described in detail later) are generated. Is done. When the temperature at the center of the cooler 21 is about 600 ° C., the temperature of the mixed gas G6 after the bleed gas G4 and the cooling gas G5 are mixed becomes approximately 350 ° C. or less.

  When the bleed gas G4 is cooled by the cooler 21 to the heat-resistant temperature of the dust collector 22, the amount of generated gas tends to increase and the efficiency of the dust collector 22 tends to decrease. Therefore, the mixed gas G6 before being introduced into the dust collector 22 may be cooled. As a method of cooling the mixed gas G6, for example, a cooling fluid (a liquid such as the cooling gas G5 or another gas or water) may be supplied to the mixed gas G6, a heat exchanger may be used, The gas G6 may be cooled naturally by passing through a long pipe, or a combination thereof.

  The dust collector 22 is a so-called bag filter, and captures particles in the mixed gas G6 introduced from the cooler 21. The particles in the mixed gas G6 include fine particles, coarse particles, and large particles having a large diameter from the beginning (hereinafter, the coarse particles and the large particles are collectively referred to as “coarse particles”). The collected particles are discharged from the dust collector 22 as bypass dust M4 and collected in a dust tank (not shown) or the like. The mixed gas G6 after the bypass dust M4 has been collected is discharged from the dust collector 22 as a dust collector exhaust gas G7. In order to stabilize the operation of the air extraction device 20, a gravity sedimentation chamber or the like is disposed downstream of the cooler 21 and upstream of the dust collector 22 (for example, immediately after the cooler 21), and the large particles of 1 mm or more are clinker-fired. It may be returned to the device 10. In this case, the amount of particles of 1 mm or more going to the dust collector 22 is reduced, so that the accumulation of particles on the duct can be suppressed. Therefore, the duct is less likely to be blocked by the particles.

  The water supply device 23 is configured to spray water directly on the cooling gas G5. When water is sprayed on the cooling gas G5 by the water supply device 23, the cooling gas G5 flows toward the cooler 21 with accompanying water droplets. The diameter of the water droplet accompanied by the cooling gas G5 is preferably 20 μm or less, more preferably 10 μm or less. When the diameter of the water droplet is 20 μm or less, the water droplets hardly collide with each other to form large-diameter water droplets. When the diameter of the water droplet is 10 μm or less, the water droplet is hardly separated from the cooling gas G5, and the cooling gas G5 tends to flow along with most of the water droplet.

Here, regarding the relationship between the size of the water droplet and the size of the KCl crystal obtained by cooling with the water droplet of the size, the heat energy required to evaporate the water droplet and the heat energy required to generate the KCl crystal is calculated. Consider based on balance. The mass of a spherical water droplet having a diameter of 30 μm is about 14 ng, and the mass of a KCl crystal (specific gravity: 2.0) having a cube of 10 μm on a side is about 2 ng. The enthalpy for cooling the bleed gas G4 from 1000 ° C. to 600 ° C. is about 200 kcal / m ^3N , and the enthalpy for converting water at normal temperature to steam at 600 ° C. is about 850 cal / g. Accordingly, the volume of the extracted gas G4 that can be cooled from 1000 ° C. to 600 ° C. by the water droplet having the mass of 14 ng is about 60 pm ^3N from 14 [ng] × 850 [cal / g] ÷ 200 [kcal / m ^3N ]. Since the gas in the standard state is 22.4 L / mol, the bleed gas G4 at this time corresponds to about 2.7 nmol. On the other hand, since the molecular weight of KCL is 74.6, Kng having a mass of 2 ng corresponds to 0.027 nmol. Here, since the mass of the generated KCl crystal is extremely small and ignoring the heat of crystallization of KCl, it is 0.027 / 2.7 ≒ 1%. Therefore, about 1% of KCl vapor is extracted in the extracted gas G4 at 1000 ° C. %, 14 ng of water at room temperature is added thereto, whereby a bleed gas at 600 ° C. and 2 ng of KCl crystals can be obtained. Since the KCl vapor concentration in the bleed gas G4 is about 0.5% to 3%, which is about 1%, KCl is actually crystallized with the above heat balance. This is the same even when the length, width and height are all 1/10, so that a KCl crystal having a diameter of about 1 μm is obtained from a water droplet having a diameter of about 3 μm.

  On the other hand, a KCl crystal having a diameter of about 1 μm can be obtained by the cooling gas G5 that does not accompany water droplets. However, the cooling capacity was low in the air cooling using the cooling gas G5, and the maximum diameter of the obtained KCl crystal was about 1 μm. Therefore, it is preferable that the diameter of the water droplet accompanied by the cooling gas G5 is larger than 3 μm. When the cooling is performed by spraying the cooling gas G5 as described above, the cooling capacity is higher than that of the air cooling, but the volatile components are gradually cooled as compared with the case where the water is sprayed directly into the cooler 21. Therefore, coarse particles having a larger diameter can be effectively obtained.

  In the present embodiment as described above, the water supply device 23 is configured to spray water directly on the cooling gas G5 before being introduced into the cooler 21. Therefore, the water droplets accompanying the cooling gas G5 due to the water spray from the water supply device 23 are gradually mixed with the bleed gas G4 while moving along the flow of the cooling gas G5, so that the water droplets gradually cool the volatile components. . Therefore, the volatile component can be gradually solidified into a seed crystal, and the crystal growth is effectively promoted. As a result, coarse particles having a relatively large particle size (that is, fine particles are coarsened) obtained by solidifying the volatile component are obtained, and the adhesive force of the coarse particles is weakened. As described above, clogging of the bag filter (pressure loss) and blockage of the flow path are suppressed, so that it is possible to improve the operation efficiency of the extraction device 20 (operate the extraction device 20 with energy saving). In addition, since the amount of payment of the bag filter can be reduced, the life of the bag filter can be extended.

  By the way, the amount of 0.5% to 3% of the value of chlorine contained in the bypass dust M4 is included in the raw material dust accompanying the kiln exhaust gas G2 before the bleeding, and the value of the value exceeding the value is 0.5% to 3%. Is a result of condensation of volatile components volatilized in the kiln exhaust gas G2. Therefore, when the chlorine concentration of the bypass dust M4 is high, it means that there are many fumes composed of fine particles having a particle size on the order of submicron (less than 1 μm), and the fine particles have a strong adhesive force. Therefore, in order to reduce the adhesion of the microparticles and perform the operation of the bleeding device 20 well, the ratio of the raw material dust in the bypass dust M4 is increased, and the chlorine concentration of the bypass dust M4 is less than 20%, preferably 15% or less. Was to be done.

  However, in the present embodiment, coarse particles having weak adhesion are generated by coarsening the fine particles, so that the chlorine concentration of the bypass dust M4 is reduced by increasing the ratio of the raw material dust in the bypass dust M4. Is not always required. Therefore, according to the present embodiment, even if the chlorine concentration of the bypass dust M4 is 15% or more, or 20% or more, the bleeding device 20 can be favorably operated.

  In the present embodiment, the air extraction device 20 is configured so that dust collected in the air extraction device 20 hardly returns to the clinker firing device 10. Therefore, most of the chloride contained in the extraction gas G4 can be collected in the extraction device 20 as bypass dust M4. Therefore, the recovery efficiency of chlorine and the like with respect to the extraction rate becomes extremely high. Further, since almost no dust containing chlorine is returned from the extraction device 20 to the clinker firing device 10, the extraction device 20 can be downsized.

  As described above, the embodiments according to the present disclosure have been described in detail. However, various modifications may be added to the above embodiments within the scope of the present invention. For example, as shown in FIG. 2, the bleeding device 20 may further include an auxiliary water supply 24 configured to spray water into the cooler 21. The diameter of water droplets sprayed on the bleed gas G4 in the cooler 21 by the auxiliary water supply device 24 is preferably about 100 μm or more. In this case, even if there is no nozzle extending toward the center of the cooler 21, water drops are not hindered by the cooling gas G <b> 5 flowing along the inner wall surface of the cooler 21 and the bleed gas G <b> 4 flowing through the center of the cooler 21 does not. Tend to reach easily.

  In the bleed device 20 shown in FIG. 2, as described above, water is sprinkled into the cooler 21 from the auxiliary water device 24 different from the water device 23, but the bleed device 20 does not have the auxiliary water device 24, The water supply device 23 may spray water on both the cooling gas G5 and the cooling device 21. That is, the bleeding device 20 shown in FIG. 2 only needs to have a water supply means (water supply device) configured to spray water into the cooler 21.

  As shown in FIG. 3, the bleeding device 20 may further include a circulation flow path configured to return a part of the mixed gas G <b> 6 discharged from the cooler 21 to the cooler 21. The mixed gas G6 may include coarse particles and fine particles that have not been coarsened. In this case, at least a part of the fine particles present in the mixed gas G6 is circulated through the circulation channel. It returns to the cooler 21 as gas G8. Therefore, the fine particles having a strong adhesive force to the bag filter, the flow path, and the like are suppressed from going downstream (toward the dust collector 22). The fine particles in the circulating gas G8 that returns to the cooler 21 through the circulation flow path contact the bleed gas G4 in the cooler 21 to become seeds, and the volatile components are solidified on the surface of the fine particles. Therefore, the fine particles are coarsened while the volatile components in the extracted gas G4 are prevented from becoming fumes alone. As described above, it is possible to further improve the operation efficiency of the extraction device 20. Furthermore, since the amount of gas directed to the dust collector 22 is reduced, the size of the equipment such as the dust collector 22 can be reduced. The diameter of the seed fine particles is on the order of submicron. However, when the fine particles are cooled by water droplets, the crystals grow to, for example, 3 μm or more, and clogging of the bag filter (pressure loss) and flow. Road blockage and the like are suppressed.

  In FIG. 3, as a configuration for returning a part of the mixed gas G6 to the cooler 21 via the circulation flow path, a classification device (for example, a cyclone, an inertial dust collector, or the like) is provided at a branch point of the circulation flow path. Then, fine particles having a predetermined particle size or less (for example, 10 μm or less) may be circulated through the circulation channel, and particles having a larger particle size may be circulated through the dust collector 22. At this time, the particles heading for the dust collector 22 may be extracted from the dust collector together with the gas. Alternatively, a circulation flow path (flue of the circulating gas G8) may be connected so as to branch from a straight pipe portion of the flue gas flue of the cooler 21, and classification may be performed using inertial force.

  The circulation gas G8 may be suitably mixed with the bleed gas G4. Therefore, the circulating gas G8 may be returned directly to the cooler 21 as shown in FIG. 3, or may be returned to the cooler 21 together with the extracted gas G4 after being sprayed on the extracted gas G4.

  The circulating gas G8 may be returned to the cooler 21 after being cooled. For example, the mixed gas G6 before being branched into the circulation channel (all of the mixed gas G6 discharged from the cooler 21) may be cooled, or the circulated gas G8 after being branched from the mixed gas G6 may be cooled. May be. As a cooling method of the circulating gas G8, for example, a cooling fluid (a cooling gas G5 or another gas, a liquid such as water) may be supplied also to the mixed gas G6, a heat exchanger may be used, or a circulating gas may be used. The gas G8 may be cooled naturally by passing through a long pipe, or a combination thereof. Since the amount of the cooling gas G5 can be reduced by cooling the circulating gas G8, the size of the bleeding device 20 can be further reduced.

  In the embodiment shown in FIG. 3, similarly to the embodiment shown in FIG. 2, the bleeding device 20 has a water supply device for spraying water into the cooler 21, that is, a water supply means (water supply device) for directly spraying water to the bleed gas G <b> 4. May be.

  As shown in FIG. 4, the bleeding device 20 further includes a circulation flow path configured to return a part of the particles (bypass dust M4) discharged from the dust collector 22 to the cooler 21 as circulation dust M5. You may have. Although FIG. 1 illustrates that the circulating dust M5 is directly supplied to the cooler 21, the circulating dust M5 may be mixed with the bleed gas G4. Accordingly, the circulating dust M5 may be returned to the cooler 21 after being mixed with the cooling gas G5, or the circulating dust M5 may be returned to the cooler 21 after being mixed with the bleed gas G4.

  When the fine particles included in the bypass dust M4 come into contact with the bleed gas G4 in the cooler 21, the volatile component solidifies and grows on the surface of the seed fine particles. Therefore, the fine particles are coarsened while the volatile components in the extracted gas G4 are prevented from becoming fumes alone. Accordingly, the fine particles are coarsened, the adhesive force is weakened, and the number of the fine particles is reduced, whereby clogging of the bag filter (pressure loss) and blockage of the flow path are suppressed. As a result, it is possible to improve the operation efficiency of the extraction device 20. Further, when a part of the fine particles having a strong adhesive force is returned toward the cooler 21, the fine particles are suppressed from going downstream (toward the dust collector 22). Therefore, it is possible to further improve the operation efficiency of the extraction device 20. Further, since the pressure loss is reduced, it is possible to reduce the size of facilities such as the dust collector 22. The submicron-order fine particles grow as seeds and eventually aggregate to form coarse particles. When the apparent specific gravity of the coarse particles is, for example, 2 or more, if the particle size of the coarse particles is 3 μm, the adhesion of the particles is considerably weakened, and clogging of the bag filter and blockage of the flow path are suppressed, and coarse particles are formed. When the particle size of the activated particles is 5 μm or more, the adhesion of the particles is further weakened, and clogging of the bag filter and blockage of the flow path are sufficiently suppressed. Further, when the particle size of the coarse particles is 10 μm or more and the apparent specific gravity of the coarse particles is 1 or more, clogging of the bag filter (pressure loss) and blockage of the flow path are extremely suppressed. The ratio (M5 / M4) of returning the bypass dust M4 to the cooler 21 as the circulating dust M5 may be appropriately set according to the particles contained in the circulating dust M5. Specifically, when the average particle diameter of the particles contained in the circulating dust M5 is large (for example, 10 μm or more), the coarse particles having a particle diameter of 10 μm or more are set by setting the ratio to about 20% to 50%. Is easier to obtain. On the other hand, when the average particle size of the particles contained in the circulating dust M5 is small, a sufficient seed crystal can be obtained even if the ratio is reduced.

  In the present specification, the “apparent specific gravity” refers to the mass of the particle P and the same volume of water W (see FIG. 6A) as the particle P (see FIG. 6A). 6 (b)). The volume of the water W shown in FIG. 6B is equal to the volume of a virtual bag closely attached to the outer shape of the particle P shown in FIG. In addition to the hatched portion), a void P1 existing inside the particle P and a void P2 existing on the surface of the particle P are included. In addition, "apparent specific gravity" can be similarly defined for aggregated particles to which a plurality of particles adhere and behave as apparently one particle, and the mass of the aggregated particles and the mass of water having the same volume as the aggregated particles are calculated. The ratio of The volume of the agglomerated particles is equal to the volume of a virtual bag closely attached to the outer shape of the agglomerated particles, and in addition to the substantial part of the agglomerated particles, a void existing inside the agglomerated particles or a surface of the agglomerated particles. Including vacancies existing in

  In FIG. 4, the circulating dust M5 may include fine particles, or may include coarse particles. The coarse particles in the cooler 21 may have a particle diameter of 30 μm or more and an apparent specific gravity of 1 or more. In this case, since the weight of the coarse particles is heavy, the coarse particles are easily pressed against the inner wall surface of the cooler 21 by centrifugal force. Therefore, the coarse particles can clean the inner wall surface of the cooler 21 to suppress the growth of the coating. Since such a cleaning effect can be expected in the flow path of the powder, the flowability of the powder in the flow path can be improved.

  In the embodiment shown in FIG. 4, similarly to the embodiment shown in FIG. 2, the bleeding device 20 has a water supply device that sprays water into the cooler 21, that is, a water supply unit (water supply device) that directly sprays water onto the bleed gas G <b> 4. May be.

  As shown in FIG. 5, if the water supply device 23 is configured to cause water droplets to accompany the cooling gas G5 before being introduced into the cooling device 21, it is not necessary to spray water directly on the cooling gas G5. Specifically, the air extraction device 20 may be configured such that the water supply device 23 sprays water on the circulating gas G8 flowing through the circulation channel, and blows the sprayed circulating gas G8 onto the cooling gas G5. Since the circulating gas G8 has a higher temperature and a longer residence time than the cooling gas G5, when water is sprayed on the circulating flow path, water droplets volatilize before entering the cooler 21 and have a small diameter. Therefore, water droplets having a relatively large diameter can be sprinkled into the circulation channel. The larger the diameter of the water droplet to be sprinkled, the smaller the energy required to generate the water droplet, which tends to require less energy.

  In the embodiment shown in FIG. 5, similarly to the embodiment shown in FIG. 2, the bleeding device 20 has a water supply device for spraying water into the cooler 21, that is, a water supply means (water supply device) for directly spraying water to the bleed gas G <b> 4. May be.

  In the embodiment shown in FIG. 5 as well, as in the embodiment shown in FIG. 3, the fine particles are circulated toward the cooler 21 by the circulation gas G8 and coarsened. Can be reduced. Therefore, it is possible to reduce the size of equipment such as the dust collector 22. Further, since the amount of the cooling gas G5 can be reduced by cooling the circulating gas G8, the size of the cooler 21 (the air extraction device 20) can be further reduced.

  In the above-described embodiment, a bag filter is described as an example of the dust collector 22, but various filters may be employed. For example, when an electric precipitator is used as the precipitator 22, it is possible to reduce the amount of fine particles re-scattered when hammering out dust attached to the electrode of the electric precipitator. Therefore, it is possible to suppress the blockage of the transport system for the gas and the fine particles.

  DESCRIPTION OF SYMBOLS 1 ... Clinker manufacturing apparatus, 10 ... Clinker baking apparatus, 11 ... Baking furnace, 12 ... SP (suspension preheater), 20 ... Bleeding apparatus, 21 ... Cooler, 22 ... Dust collector, 23 ... Water supply, 24 ... Auxiliary Water feeder, G1 gas, G2 kiln exhaust gas, G3 SP exhaust gas, G4 extraction gas, G5 cooling gas, G6 mixed gas, G7 dust collector exhaust gas, G8 circulating gas, M1 raw material, M2 ... Kiln raw material, M3: clinker, M4: bypass dust, M5: circulating dust.

Claims (12)

A bleed gas from a cement clinker firing device, and a cooler into which a cooling gas for cooling the bleed gas is introduced,
A water supply configured to cause water droplets to accompany the cooling gas before being introduced into the cooler ,
A bleeding device, comprising: a circulating flow path configured to return a part of particles discharged from the cooler and accompanied by a mixed gas of the bleed gas and the cooling gas to the cooler .   The bleed device according to claim 1, wherein the water supply is configured to spray water on the cooling gas.   The bleed apparatus according to claim 1 or 2, further comprising an auxiliary water supply configured to spray water into the cooler. The mixed gas from the cooler is introduced, further comprising a dust collector configured to collect dust contained in the mixed gas,
The air extraction device according to any one of claims 1 to 3, wherein the circulation channel is configured to return a part of the dust collected by the dust collector to the cooler. The bleed device according to any one of claims 1 to 4, wherein the circulation channel is configured to return a part of the mixed gas to the cooler. The air extraction device according to any one of claims 1 to 5 , wherein the water supply device is configured to spray water to the circulation flow path. A first step of introducing a bleed gas extracted from the cement clinker firing device into a cooler;
A second step of causing water droplets to accompany the cooling gas before being introduced into the cooler;
A third step of introducing the cooling gas accompanied by water droplets into the cooler, and cooling the bleed gas introduced into the cooler with the cooling gas ;
A fourth step of returning a part of the particles discharged from the cooler and accompanying the mixed gas of the bleed gas and the cooling gas to the cooler, to a fourth step . The bleed air according to claim 7 , wherein, in the second step, water droplets accompany the cooling gas before being introduced into the cooler by spraying water on the cooling gas before being introduced into the cooler. Method. 9. The bleeding method according to claim 7 , wherein, in the third step, the cooling gas accompanied by water droplets is introduced into the cooler and water is sprinkled into the cooler. 10. In the fourth step,
Introducing the mixed gas from the cooler to a dust collector to collect dust contained in the mixed gas;
The air extraction method according to any one of claims 7 to 9 , wherein a part of dust collected by the dust collector is returned to the cooler. The bleeding method according to any one of claims 7 to 10, wherein in the fourth step, a part of the mixed gas is returned to the cooler. Wherein in the fourth step, by sprinkling the exhaust gas before returning to and the cooler is discharged from the cooler, thereby entrain water droplets in the cooling gas before being introduced into the cooler, claim 7 The bleeding method according to any one of claims 11 to 13 .

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