JP2017120138A - Bleeding device and bleeding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the operation efficiency of a bleeding device.SOLUTION: A bleeding device 20 includes: a cooler 21 to which a bled gas G4 from a clinker burning device 10 and a cooling gas G5 for cooling the bled gas G4 are introduced; and a circulation passage which is formed so as to return part of particles entrained by a mixed gas G6, which is discharged from the cooler 21 and formed by mixing the bled gas G4 with the cooling gas G5, to the cooler 21.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to an extraction device and an extraction method.

Cement clinker (hereinafter referred to as “clinker”) is usually manufactured through a process of firing a raw material in a kiln (rotary furnace) with a combustion gas such as pulverized coal having a maximum temperature of 2000 ° C. or higher. In the kiln, the raw material is heated to about 1450 ° C. Therefore, even if the waste is used as the raw fuel, the organic matter contained in the waste is decomposed to the level of CO ₂ or H ₂ O that does not leave the properties of the original molecules. 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.

  The kiln exhaust gas discharged from the kiln is usually at a high temperature of 900 ° C. or higher. Therefore, for the purpose of improving energy efficiency, it is common to recover heat from the kiln exhaust gas by connecting a suspension preheater (hereinafter referred to as “SP”) to the kiln, preheating the raw material and putting it into the kiln. Has been done. Since the SP exhaust gas discharged from the SP is also about 300 ° C. to 400 ° C. and is still at a high temperature, the heat is further recovered by drying the raw material, a power generation boiler, etc., and the gas after the heat recovery at a low temperature is returned to the atmosphere Discharge.

  By the way, in the clinker baking apparatus containing kiln and SP, the gas flows in the direction opposite to the raw material charged into the clinker baking apparatus in the system. That is, the gas flow and the raw material flow are generally countercurrent. For this reason, components (volatile components) that easily produce volatile substances in the raw fuel are vaporized in the high-temperature kiln, but become low-melting compounds in the SP, which is lower in temperature than in the kiln, and enter the kiln again. By returning, it circulates in the system (in the clinker baking apparatus) and can be gradually concentrated. The concentrated component takes a paste-like form and can adhere to the clinker baking apparatus. Such deposits are sometimes referred to as coating.

  When the coaching grows in the clinker baking apparatus, the flow of raw materials and gas is hindered. However, as described above, as the amount of waste used as a raw fuel increases, chlorine, which is an element that is extremely easy to produce a low-melting-point material, has increased particularly in the clinker baking apparatus. Chlorine binds to many metal atoms and becomes a relatively stable molecule with a high saturated vapor pressure, so it is easy to circulate in the system. Therefore, there is a concern about an increase in the amount of coaching.

  Therefore, Patent Documents 1 and 2 disclose a process of extracting a component such as chloride from a clinker baking apparatus (a technique called “chlorine bypass”). Specifically, a part of the kiln exhaust gas is guided to the cooling chamber, and the kiln exhaust gas is cooled with cooling air (Patent Document 1) or cooling water (Patent Document 2) in the cooling chamber, thereby solidifying the volatile component. It has been removed.

JP 09-175847 A JP 2014-014730 A

  When volatile components are cooled in the cooling chamber, they become fume and solidify. The fume is composed of fine particles having a particle size on the order of submicron (less than 1 μm). Such microparticles or aggregated particles obtained by agglomerating the microparticles (hereinafter collectively referred to as “microparticles”) have strong adhesive force, and therefore are difficult to remove from the filter when the microparticles are collected by the filter. Filter clogging (pressure loss) can occur. In addition, fine particles may adhere to a flow path of fine particles (for example, a dust collector and a bypass dust transport system) located on the downstream side of the cooling chamber to block them. Therefore, when the chlorine bypass described in Patent Documents 1 and 2 can be performed, the amount of coaching can be suppressed, but filter replacement work or flow path cleaning work frequently occurs, and the operation of the chlorine bypass is frequently interrupted. sell.

  Therefore, the present disclosure describes an extraction device and an extraction method that can improve the operation efficiency.

First, terms used in this specification are defined as follows.
“Bleeding” refers to extracting gas from a clinker baking apparatus.
“Bleeding gas” refers to a gas extracted from a clinker baking apparatus.
“Raw material dust” refers to a raw material accompanying the extracted gas.
The “bleeding device” refers to a device that cools the extracted gas and solidifies volatile components.
“Bypass dust” refers to dust collected together with raw material dust by an extraction device.
In addition, in this specification, the term “gas” is intended to include dust accompanying the gas in addition to the gas itself.

  An extraction device according to one aspect of the present disclosure includes an extraction gas from a cement clinker firing device, a cooler into which a cooling gas for cooling the extraction gas is introduced, and a gas discharged from the cooler, the extraction gas And a circulation channel configured to return a part of the particles accompanying the mixed gas of the gas and the cooling gas to the cooler.

  In the extraction device according to one aspect of the present disclosure, the circulation channel is configured to return a part of the particles accompanying the mixed gas of the extraction gas and the cooling gas discharged from the cooler as the exhaust gas to the cooler. It is. That is, in the cooling chamber, volatile components are cooled and fumes are generated, so that some of the fine particles constituting the fumes are returned to the cooling chamber through the circulation channel. When the microparticles come into contact with the bleed gas in the cooler, they become seeds and solidify and grow on the surface of the microparticles. Therefore, the volatile component in the extraction gas can be prevented from becoming fumes alone, and the fine particles can be coarsened. Accordingly, the fine particles are coarsened, the adhesion force is weakened, and the number is reduced, 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 operating efficiency of the extraction device. In addition, when a part of the fine particles having strong adhesion force is returned to the cooler, the fine particles are suppressed from moving toward the downstream side (the dust collector side). Therefore, it becomes possible to improve the operating efficiency of the bleeder. Furthermore, since pressure loss is reduced, it is possible to reduce the size of equipment such as a dust collector.

  The bleeder according to one aspect of the present disclosure further includes a dust collector configured to collect the dust contained in the mixed gas, to which the mixed gas from the cooler is introduced, and the circulation channel includes You may be comprised so that some dust collected by the duster may be returned to a cooler.

  The circulation channel may be configured to return a part of the mixed gas to the cooler. In this case, since the amount of gas directed to the dust collector is reduced, it is possible to further downsize the equipment such as the dust collector.

  The bleeder according to one aspect of the present disclosure may further include a water supply device configured to spray water in the cooler. In this case, since the volatile component is cooled by watering from the water supply device, the volatile component is easily solidified and deposited on the surface of the fine particles. Therefore, it becomes possible to promote the coarsening of the fine particles.

  In the extraction method according to another aspect of the present disclosure, a first step of introducing the extraction gas extracted from the cement clinker firing apparatus into the cooler, and introducing the cooling gas into the cooler and introducing the cooling gas into the cooler A second step of cooling the extraction gas with the cooling gas, and a third step of returning a part of the particles discharged from the cooler and accompanying the mixed gas of the extraction gas and the cooling gas to the cooler. including.

  In the extraction method according to another aspect of the present disclosure, in the third step, a part of the particles accompanying the mixed gas of the extraction gas and the cooling gas discharged from the cooler as the exhaust gas is returned to the cooler. . That is, in the cooling chamber, volatile components are cooled and fumes are generated, so that some of the fine particles constituting the fumes are returned to the cooling chamber. The fine particles come into contact with the extraction gas in the cooler to become seeds, and volatile components are solidified on the surface of the fine particles. Therefore, the volatile component in the extraction gas can be prevented from becoming fumes alone, and the fine particles can be coarsened. Accordingly, the fine particles are coarsened and the adhesion is weakened, and clogging of the filter (pressure loss) and blockage of the flow path are suppressed. As a result, it is possible to improve the operating efficiency of the extraction device. Moreover, since a part of microparticles with strong adhesive force are returned toward the cooler, the microparticles are prevented from moving toward the downstream side (dust collector). Therefore, it becomes possible to improve the operating efficiency of the bleeder. Furthermore, since pressure loss is reduced, it is possible to reduce the size of equipment such as a dust collector.

  In the third step, the mixed gas from the cooler is introduced into the dust collector to collect the dust contained in the mixed gas, and a part of the dust collected by the dust collector is returned to the cooler. You may do that. In this case, since the amount of gas directed to the dust collector is reduced, it is possible to further downsize the equipment such as the dust collector.

  In the third step, part of the mixed gas may be returned to the cooler.

  In the second step, the extraction gas introduced into the cooler may be cooled with the cooling gas while sprinkling water into the cooler. In this case, since the volatile component is cooled by watering from the water supply device, the volatile component is easily solidified and deposited on the surface of the fine particles. Therefore, it becomes possible to promote the coarsening of the fine particles.

  According to the bleeding device and the bleeding method according to the present disclosure, it is possible to improve the operation efficiency of the bleeding 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 view showing another example (second example) of the clinker manufacturing apparatus according to this embodiment. FIG. 3 is a schematic diagram showing another example (third example) of the clinker manufacturing apparatus according to the present embodiment. FIG. 4 is a diagram for explaining the definition of apparent specific gravity.

  Since the embodiment according to the present disclosure described below is an example for explaining the present invention, the present invention should not be limited to the following contents. In the following description, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted.

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

  The clinker firing apparatus 10 includes 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 fire 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 the clinker M3. The temperature of the gas G1 introduced into the clinker cooler may be about room temperature, for example. The gas G1 heat-exchanged in the clinker cooler is heated to, for example, about 500 ° C. to 1000 ° C., and is used for combustion of fuel such as pulverized coal (not shown) in the kiln. The maximum temperature of the combustion gas in the kiln is usually above 2000 ° C. The combustion gas burns the kiln raw material M2, and is discharged from the kiln as the kiln exhaust gas G2. The temperature of the kiln exhaust gas G2 is usually about 900 ° C to 1250 ° C.

  SP12 is an apparatus for preheating the raw material M1 for the purpose of increasing the firing efficiency of the kiln raw material M2 in the firing furnace 11. The SP 12 includes a plurality of stages (for example, about 4 to 5 stages) of cyclones (separators). When the raw material M1 is introduced into the tower top of SP12, the kiln exhaust gas G2 introduced from the tower bottom of SP12 and the raw material M1 are sequentially heat-exchanged in each stage cyclone, and the raw material M1 is preheated to about 850 ° C., for example. It becomes the raw material M2. The kiln raw material M2 produced | generated in SP12 is discharged | emitted from the tower bottom part, and is introduce | transduced into the baking furnace 11. FIG. On the other hand, kiln exhaust gas G2 is discharged from the top of SP12 as SP exhaust gas G3 after heat exchange with raw material M1. 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 the raw material, a power generation boiler or the like, and the heat-recovered gas that has become low temperature is discharged to the atmosphere. The SP 12 may be a new suspension preheater (NSP) further including a calcining furnace provided between the lowest stage of the cyclone and the firing furnace 11. In NSP, fuel (for example, pulverized coal) is supplied to a calcining furnace and the raw material M1 is calcined to increase the production amount and firing efficiency of the clinker M3.

  In the clinker baking apparatus 10, the gas flows in approximately the opposite direction to the raw material M <b> 1 charged into the clinker baking apparatus 10 (SP12) in the system. Therefore, although the volatile component is vaporized in the high temperature kiln, it is liquefied or solidified in the SP 12 having a temperature lower than that in the kiln, and then circulates in the clinker baking apparatus 10 by returning to the kiln again. If volatile components are concentrated during this circulation, coaching can occur. In recent years, as the amount of waste used as a raw fuel increases, the content of chlorine, which is an element that is extremely easy to produce a low-melting-point material, has increased particularly, and there is concern about an increase in the amount of coaching generated.

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

  The bleeder 20 includes a cooler 21 and a dust collector 22. The cooler 21 is configured to cool the extracted gas G <b> 4 from the clinker baking apparatus 10. The cooler 21 includes a main duct for extracting and exhausting the extracted gas G4, and a sub duct into which the cooling gas G5 is introduced. For example, the main duct is provided with an enlarged portion enlarged in the radial direction, and the sub duct is connected to the enlarged portion so as to extend in the tangential direction of the inner wall surface of the enlarged portion. Extracted gas G4 is introduced into the cooler 21 from the bottom of the tower, and cooling gas G5 is introduced from the duct. The gas used as the cooling gas G5 is not particularly limited as long as the extraction gas G4 can be cooled. For example, air may be used. The temperature of the cooling gas G5 introduced into the cooler 21 may be about room temperature, for example.

In the cooler 21, the central portion of the cooler 21 is high temperature and the wall portion is low temperature, and the temperature distribution is considerably non-uniform. Therefore, in the cooler 21, the extracted gas G4 and the cooling gas G5 are not so mixed. Therefore, the volatile component contained in the extracted gas G4 (kiln exhaust gas G2) is prevented from reaching the inner wall surface and hardly solidifies on the inner wall surface of the cooler 21 (it is difficult to 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 these solidify sufficiently can be influenced by various factors (for example, a decrease in melting point due to eutectic, agglomeration heat when gas is liquefied / solidified, reaction heat during desulfurization, etc.). It is. On the other hand, the extraction gas G4 and the cooling gas G5 are mixed in the cooler 21, the solidification of the volatile component is promoted, and fine particles or coarse particles (details will be described later) generated by coarsening the fine particles are generated. Is done. When the temperature of the central portion of the cooler 21 is about 600 ° C., the temperature of the mixed gas G6 after the extraction gas G4 and the cooling gas G5 are mixed is approximately 350 ° C. or less.

  When the extraction gas G4 is cooled to the heat resistant temperature of the dust collector 22 by the cooler 21, the amount of gas generated increases, and the efficiency in 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 cooling method of the mixed gas G6, for example, a cooling fluid (cooling gas G5 or other gas, liquid such as water) may be supplied to the mixed gas G6, a heat exchanger may be used, or mixing may be performed. The gas G6 may be naturally cooled by passing through a long pipe, or these may be combined.

  The dust collector 22 is a so-called bag filter and collects particles in the mixed gas G <b> 6 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 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 is collected is discharged from the dust collector 22 as the dust collector exhaust gas G7. In order to stabilize the operation of the bleeder 20, a gravity settling chamber or the like is arranged after the cooler 21 and before the dust collector 22 (for example, immediately after the cooler 21), and large particles of 1 mm or more are clinker fired. You may return to the apparatus 10. In this case, since the amount of particles having a size of 1 mm or more toward the dust collector 22 is reduced, accumulation of particles on the duct can be suppressed. Therefore, it becomes difficult for the duct to be blocked by particles.

  The bleeder 20 further includes a circulation channel 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. In FIG. 1, the circulating dust M5 is depicted as being directly supplied to the cooler 21, but the circulating dust M5 may be mixed with the extraction gas G4. Accordingly, the circulating dust M5 may be mixed with the cooling gas G5 and then returned to the cooler 21, or the circulating dust M5 may be mixed with the extraction gas G4 and then returned to the cooler 21.

  Circulating dust M5 may contain fine particles or coarse particles. The coarse particles in the cooler 21 may have a particle size 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, coarse particles can clean the inner wall surface of the cooler 21 and suppress the growth of coaching. Since such a cleaning effect can be expected in the powder flow path, the fluidity of the powder can be improved in the flow path.

  In the present specification, the “apparent specific gravity” refers to the mass of the particle P and the water W (with the same volume as the particle) in the particle P (see FIG. 4A) that apparently behaves as one particle. It refers to the ratio to the mass of FIG. The volume of water W shown in FIG. 4 (b) is equal to the volume of a virtual bag that is in close contact with the outer shape of the particle P shown in FIG. 4 (a). In addition to the hatched portion, it includes voids P1 existing inside the particles P and holes P2 existing on the surface of the particles P. The “apparent specific gravity” can also be defined in the same manner for aggregated particles in which a plurality of particles adhere and behave as one particle apparently, and the mass of the aggregated particles and the mass of water of the same volume as the aggregated particles The ratio of The volume of the agglomerated particles is equal to the volume of a virtual bag that is in close contact with the outer shape of the agglomerated particles, and in addition to the substantial part of the agglomerated particles, the voids present inside the agglomerated particles and the surface of the agglomerated particles Including vacancies existing in

  In the present embodiment as described above, a part of the bypass dust M4, that is, a part of the particles accompanying the mixed gas G6 is returned to the cooler 21 by the circulation channel. That is, since the volatile component is cooled in the cooler 21 to generate fume, a part of the fine particles constituting the fume is returned to the cooler 21 through the circulation channel. When the microparticles contained in the bypass dust M4 come into contact with the extraction gas G4 in the cooler 21, volatile components are solidified and grow on the surface of the microparticles that have become seeds. Therefore, the volatile component in the extraction gas G4 is suppressed from becoming fumes alone, and the fine particles are coarsened. Accordingly, the fine particles are coarsened, the adhesion force is weakened, and the number is reduced, so that the clogging (pressure loss) of the bag filter and the blockage of the flow path are suppressed. As a result, it is possible to improve the operation efficiency of the bleeder 20. In addition, when some of the fine particles having strong adhesion force are returned toward the cooler 21, the fine particles are prevented from moving toward the downstream side (the dust collector 22 side). Therefore, it becomes possible to further improve the operation efficiency of the bleeder 20. Furthermore, since pressure loss is reduced, it is possible to downsize equipment such as the dust collector 22. Submicron-order fine particles grow as seeds and can eventually aggregate to form coarse particles. When the apparent specific gravity of the coarse particles is 2 or more, for example, if the particle size of the coarse particles is 3 μm, the adhesion force of the particles is considerably weakened to suppress the clogging of the bag filter and the blockage of the flow path. When the particle size of the particles is 5 μm or more, the adhesion of the particles is further weakened, and the clogging of the bag filter and the blockage of the flow path are sufficiently suppressed. Further, if the coarse particles have a particle size of 10 μm or more and the apparent specific gravity of the coarse particles is 1 or more, clogging of the bag filter (pressure loss), blockage of the flow path, and the like are extremely suppressed. Further, the ratio (M5 / M4) of returning the bypass dust M4 as the circulating dust M5 to the cooler 21 may be set as appropriate according to the particles contained in the circulating dust M5. Specifically, when the average particle size of the particles contained in the circulating dust M5 is large (for example, 10 μm or more), if the ratio is set to about 20% to 50%, the coarsening has a particle size of 10 μm or more. It becomes easy to obtain particles. On the other hand, when the average particle diameter of the particles contained in the circulating dust M5 is small, a sufficient seed crystal can be obtained even if the ratio is reduced.

  By the way, 0.5% to 3% of the value of chlorine contained in the bypass dust M4 is contained in the raw material dust accompanying the kiln exhaust gas G2 before bleed, and a value exceeding this value. Is a condensation of volatile components (chlorine compounds) that have been 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 strong adhesion. Therefore, in order to reduce the adhesion force of the fine particles and perform the operation of the extraction device 20 satisfactorily, 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. It was done.

  However, in this embodiment, coarse particles with weak adhesion are generated by coarsening the fine particles, so the proportion of raw material dust in the bypass dust M4 is increased to lower the chlorine concentration of the bypass dust M4. Is not necessarily required. Therefore, according to this embodiment, even if the chlorine concentration of the bypass dust M4 is 15% or more, or 20% or more, the extraction device 20 can be operated satisfactorily.

  In the present embodiment, the bleeder 20 is configured so that the dust collected in the bleeder 20 hardly returns to the clinker baking apparatus 10. Therefore, most of the chloride contained in the extraction gas G4 can be recovered as bypass dust M4 in the extraction device 20. Therefore, the recovery efficiency of chlorine and the like with respect to the extraction rate is extremely high. Further, since the dust containing chlorine is hardly returned from the extraction device 20 to the clinker firing device 10, the extraction device 20 can be downsized.

  In the present embodiment, since the bag filter is used as the dust collector 22, coarsening of the fine particles reduces clogging (pressure loss) of the bag filter due to the fine particles and blockage of the flow path. The Therefore, it becomes possible to operate the extraction device 20 with energy saving. In addition, since the bug filter can be reduced, the life of the bug filter can be extended.

  As mentioned above, although embodiment concerning this indication was described in detail, you may add various deformation | transformation to said embodiment within the range of the summary of this invention. For example, as shown in FIG. 2, the bleeder 20 may further include a circulation channel configured to return a part of the mixed gas G6 discharged from the cooler 21 to the cooler 21. . The mixed gas G6 may contain coarse particles and fine particles that have not been coarsened. In this case, at least a part of the fine particles existing in the mixed gas G6 circulates through the circulation channel. It returns to the cooler 21 as gas G8. Therefore, it is possible to obtain the same effect as the embodiment of FIG.

  In FIG. 2, as a configuration for returning a part of the mixed gas G6 to the cooler 21 through the circulation channel, a classifier (for example, a cyclone, an inertia dust collector, etc.) is installed at the branch point of the circulation channel. Alternatively, 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, particles directed to the dust collector 22 may be extracted from the classifier together with the gas. Alternatively, classification may be performed using an inertial force by connecting a circulation channel (flue of the circulation gas G8) so as to branch from the straight pipe portion of the flue gas flue of the cooler 21.

  The circulating gas G8 may be suitably mixed with the extraction gas G4. Therefore, the circulating gas G8 may be returned directly to the cooler 21 as shown in FIG. 2, or may be returned to the cooler 21 together with the extraction gas G4 after being blown to the extraction gas G4.

  The circulating gas G8 may be returned to the cooler 21 after being cooled. For example, the mixed gas G6 before branching to the circulation channel (all of the mixed gas G6 discharged from the cooler 21) may be cooled, or the circulating gas G8 after branching from the mixed gas G6 is cooled. May be. As a cooling method of the circulating gas G8, for example, a cooling fluid (cooling gas G5 or other gas, liquid such as water) may be supplied to the mixed gas G6, a heat exchanger may be used, or circulation may be performed. The gas G8 may be naturally cooled by passing through a long pipe, or these may be combined. Since the amount of the cooling gas G5 can be reduced by cooling the circulating gas G8, the bleeder 20 can be further downsized.

  As shown in FIG. 3, the bleeder 20 may further include a water supply 23 configured to spray water into the cooler 21. The diameter of the water droplets sprayed by the water supply device 23 on the extracted gas G4 in the cooler 21 is preferably about 100 μm or more. In this case, even if there is no nozzle extending toward the central portion of the cooler 21, water droplets are applied to the extracted gas G4 flowing through the central portion of the cooler 21 without being blocked by the cooling gas G5 flowing along the inner wall surface of the cooler 21. Tends to reach.

  In FIG. 3, the bleeder 20 may be configured such that the water supply device 23 sprays the circulating gas G <b> 8 flowing through the circulation channel and returns the sprinkled circulating gas G <b> 8 to the cooler 21. Since the circulating gas G8 has a higher temperature and a longer residence time than the cooling gas G5, when water is sprayed into the circulation channel, the water droplets volatilize before entering the cooler 21 and have a small diameter. Therefore, it is possible to spray water droplets having a relatively large diameter in the circulation channel. As the diameter of the water droplets sprinkled is larger, the energy required to generate the water droplets tends to be smaller, so that it is possible to save energy for extraction.

  In the form shown in FIG. 3 as well, as in the form shown in FIG. 2, the fine particles circulate toward the cooler 21 by the circulating gas G8 and become coarse, so that the amount of fine particles collected by the dust collector 22 is increased. Can be reduced. For this reason, it is possible to reduce the size of the 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 cooler 21 (bleeding device 20) can be further downsized.

  Also in the form shown in FIG.2 and FIG.3, you may return a part of bypass dust M4 to the cooler 21 with a circulation flow path similarly to the form shown in FIG.

  In the embodiment described above, the bag filter is exemplified as the dust collector 22, but an electric dust collector may be used as the dust collector 22. When an electrostatic precipitator is used as the precipitator 22, it is possible to reduce the amount of fine particles that re-scatter when the dust attached to the electrode of the precipitator is beaten and removed. Therefore, it becomes possible to suppress blockage of the transportation system such as gas and fine particles.

  DESCRIPTION OF SYMBOLS 1 ... Clinker manufacturing apparatus, 10 ... Clinker baking apparatus, 11 ... Baking furnace, 12 ... SP (suspension preheater), 20 ... Extraction apparatus, 21 ... Cooler, 22 ... Dust collector, 23 ... Water supply device, G1 ... Gas G2 ... kiln exhaust gas, G3 ... SP exhaust gas, G4 ... extracted 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 (8)

A bleed gas from the cement clinker firing device, and a cooler into which a cooling gas for cooling the bleed gas is introduced;
A bleeder comprising: a circulation channel configured to return a part of particles discharged from the cooler and accompanying the mixed gas of the bleed gas and the cooling gas to the cooler. The gas mixture from the cooler is introduced, further comprising a dust collector configured to collect dust contained in the gas mixture;
The bleeder according to claim 1, wherein the circulation channel is configured to return a part of the dust collected by the dust collector to the cooler.   The bleeder according to claim 1 or 2, wherein the circulation channel is configured to return a part of the mixed gas to the cooler.   The bleeder according to any one of claims 1 to 3, further comprising a water feeder configured to spray water into the cooler. A first step of introducing the extracted gas extracted from the cement clinker firing device into the cooler;
A second step of introducing a cooling gas into the cooler and cooling the extraction gas introduced into the cooler with the cooling gas;
And a third step of returning a part of the particles discharged from the cooler and accompanying the mixed gas of the extraction gas and the cooling gas to the cooler. In the third step,
Introducing the mixed gas from the cooler into a dust collector to collect dust contained in the mixed gas;
The extraction method according to claim 5, wherein a part of the dust collected by the dust collector is returned to the cooler.   The extraction method according to claim 5 or 6, wherein a part of the mixed gas is returned to the cooler in the third step.   The extraction method according to any one of claims 5 to 7, wherein, in the second step, the extraction gas introduced into the cooler is cooled by the cooling gas while sprinkling water into the cooler.

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