Combustion gas extraction probe and operation method thereof

Abstract

The present invention provides a combustion gas extraction probe and an operating method thereof, wherein the combustion gas extraction probe can sufficiently cool the extracted gas even when the extraction rate is enhanced and enables operation to maintain a specified dechlorination efficiency. The probe (2) comprises: an inner tube (21) for exhausting a part of the combustion gas (G1) from the kiln (1); and a plurality of nozzles (25) penetrating the inner tube (21) for respectively ejecting cold air (C) in a direction perpendicular to the flow direction of the exhaust gas (G2) exhausted by the inner tube (21) and in a direction toward the center of the flow of the exhaust gas (G2), wherein the ratio (MC / MG) of the momentum (MC) of the cold air (C) to the momentum (MG) of the exhaust gas (G2) at each nozzle of the nozzle (25) satisfies 1.2 to 4.0 and the ratio (VC / VG) of the wind speed (VC) of the cold air (C) to the wind speed (VG) of the exhaust gas (G2) divided by the inner diameter (D) of the inner tube (21) satisfies 1.5 m ‑1 ~3.5m ‑1 The cool air is blown out in a manner similar to that of a blower (C).

Description

Technical Field

[0001] The invention relates to a combustion gas extraction probe and an operating method thereof. Background Art

[0002] The chlorine bypass system prevents the coating trouble of the kiln and preheater system caused by chlorine by extracting chlorine-containing gas from the cement manufacturing equipment and discharging it outside the system. The chlorine bypass system extracts a part of the combustion gas (hereinafter referred to as "extraction") through a combustion gas extraction probe (hereinafter referred to as "probe") installed near the kiln tail of the kiln constituting the cement manufacturing equipment. The extracted combustion gas (hereinafter referred to as "extraction gas") is mixed with low-temperature gas (hereinafter referred to as "cold air"), and the chlorine component contained in the extraction gas is transformed from a gaseous state to a solid state, and is recovered and removed to the outside of the system in the form of chlorine bypass dust with potassium chloride as the main component. It is known that by rapidly cooling the extraction gas at this time, the chlorine component will be concentrated on the fine powder side of the bypass dust.

[0003] In the chlorine bypass system, the raw material component (coarse powder) and the chlorine component (fine powder) contained in the gas are separated by a cyclone separator, the raw material component is returned to the kiln side, and the chlorine component is discharged outside the system. However, if the cooling speed is slow, the amount of chlorine component returned to the kiln side together with the coarse powder with low chlorine content concentration increases, and the chlorine removal efficiency decreases.

[0004] However, in recent years, the effective utilization of waste materials, mainly waste plastics, has been promoted for the purpose of decarbonization and reducing the cost of raw materials and fuels, and the amount of chlorine (the amount of chlorine input) brought into cement manufacturing equipment has increased. Therefore, it has become necessary to enhance the capacity of the chlorine bypass system, that is, to increase the exhaust air volume (= increase in the exhaust rate). On the other hand, if the exhaust air volume is increased, in order to cool the gas temperature to below a certain temperature, it is also necessary to increase the cold air volume (low-temperature gas volume) accordingly. In order to cope with the increase in gas velocity in the probe (keep the gas cool), for example, the probe needs to be enlarged. On the other hand, it is difficult to secure a place for the equipment for the enlargement of the chlorine bypass system including the probe, and for example, it is necessary to effectively use existing equipment to increase the gas velocity in the probe.

[0005] Patent Document 1 below describes cooling exhaust gas by ejecting low-temperature gas with momentum toward a central direction perpendicular to the suction direction of the exhaust gas and reaching the center of the cross section (cross section).

[0006] Patent Document 2 below describes cooling the exhaust gas by ejecting the low-temperature gas in a central direction perpendicular to the suction direction of the exhaust gas so that the momentum vector of the low-temperature gas has a vertical downward component.

[0007] In addition, Patent Document 3 described below describes that the exhaust gas is cooled by ejecting the low-temperature gas in such a manner that the direction of the momentum resultant vector of the low-temperature gas has a component in the direction opposite to the direction from the center of the probe cross section toward the center of gravity of the velocity distribution of the exhaust gas.

[0008] In addition, Patent Document 4 listed below describes a chlorine bypass device in which a rotating portion of a cooling pipe for introducing cold air is formed in a ring shape surrounding an exhaust pipe.

[0009] Prior art literature

[0010] Patent Literature

[0011] Patent Document 1: Japanese Patent No. 4744299

[0012] Patent Document 2: Japanese Patent No. 5411126

[0013] Patent Document 3: Japanese Patent No. 5290099

[0014] Patent Document 4: Japanese Patent No. 5051325 Summary of the invention

[0015] Problem that the invention aims to solve

[0016] In order to increase the extraction rate, as mentioned above, if the probe is enlarged, it becomes difficult for the low-temperature gas to reach the center of the probe; in addition, if the gas velocity in the probe is increased, the retention time is reduced, so the formation of the mixed cooling area in the probe is deteriorated, and it is difficult to perform short-time and uniform cooling. If the cooling of the extraction gas becomes insufficient, the amount of chlorine components returned to the kiln side together with the coarse powder with low chlorine content concentration increases, and the dechlorination efficiency of the chlorine bypass system decreases.

[0017] Patent Documents 1 to 3 all employ low temperature gas ejected at right angles to the exhaust gas flowing through the probe for cooling, but do not clearly describe operating parameters related to the ejection speed and momentum of the low temperature gas when the exhaust rate is enhanced.

[0018] In Patent Document 4, by rotating the cold air in the rotating part and flowing into the exhaust pipe, the exhaust gas and the cold air are stirred and mixed, so that the exhaust gas can be quickly cooled by the cold air. However, when the cold air is rotated and flows in, the momentum of the cold air decays before the exhaust gas and the cold air are mixed, and there is a possibility that sufficient cooling cannot be performed.

[0019] In addition, depending on the method and conditions of blowing cold air, cold air may leak to the kiln tail (backflow, penetration), promote crust adhesion (adversely affect kiln operation), and cause heat loss (increased fuel combustion).

[0020] Therefore, an object of the present invention is to provide a combustion gas extraction probe and an operating method thereof, which can sufficiently cool the extracted gas even when the extraction rate is increased and enable operation to maintain a specified dechlorination efficiency. In addition, another object of the present invention is to provide a combustion gas extraction probe and an operating method thereof, which can sufficiently cool the extracted gas even when the extraction rate is increased and can suppress the backflow of cold wind to the kiln tail.

[0021] Means used to solve problems

[0022] The combustion gas extraction probe of the present invention comprises: a gas pipe for extracting a part of the combustion gas from the kiln; and a plurality of nozzles penetrating the gas pipe for respectively ejecting low-temperature gas in a direction perpendicular to the flow direction of the exhaust gas extracted by the gas pipe and in a direction toward the center of the flow of the exhaust gas, wherein the nozzles eject the low-temperature gas in such a manner that the ratio of the momentum of the low-temperature gas at each nozzle of the nozzle to the momentum of the exhaust gas satisfies 1.2 to 4.0 and the ratio of the wind speed of the low-temperature gas to the wind speed of the exhaust gas is divided by the inner diameter of the gas pipe (m -1 ) is sprayed in a manner that satisfies 1.5 to 3.5.

[0023] In addition, the present invention provides an operation method of a combustion gas extraction probe, wherein the combustion gas extraction probe comprises: a gas pipe for extracting a portion of the combustion gas from the kiln; and a plurality of nozzles penetrating the gas pipe for respectively ejecting low-temperature gas in a direction perpendicular to the flow direction of the exhaust gas extracted from the gas pipe and in a direction toward the center of the flow of the exhaust gas. In the operation method, the ratio of the momentum of the low-temperature gas at each nozzle of the nozzle to the momentum of the exhaust gas satisfies 1.2 to 4.0, and the value obtained by dividing the ratio of the wind speed of the low-temperature gas to the wind speed of the exhaust gas by the inner diameter of the gas pipe (m -1 ) satisfies 1.5~3.5.

[0024] According to the present invention, even when the extraction rate is increased, it is possible to sufficiently cool the extraction gas and to enable operation while maintaining a predetermined chlorine removal efficiency.

[0025] The present invention provides a combustion gas extraction probe, which comprises: a gas pipe for extracting a portion of the combustion gas from a kiln; and a plurality of nozzles penetrating the gas pipe for respectively ejecting the extraction gas for extracting low-temperature gas relative to the gas pipe, wherein the plurality of nozzles are arranged in such a manner that the low-temperature gases ejected from each of the nozzles do not collide with each other in the gas pipe.

[0026] In addition, the present invention provides an operating method for a combustion gas extraction probe, which is the operating method of the above-mentioned combustion gas extraction probe, wherein the wind speed of the low-temperature gas ejected from the nozzle satisfies 25 to 180 m / s and the ratio of the momentum of the low-temperature gas at each nozzle of the nozzle to the momentum of the extraction gas satisfies 1.8 to 5.3.

[0027] According to the present invention, even when the exhaust rate is enhanced, the exhaust gas can be sufficiently cooled and the backflow of cold wind to the kiln tail can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 1 is an overall structural diagram showing a first embodiment of a chlorine bypass system including a combustion gas extraction probe according to the present invention.

[0029] Figure 2 2 is a cross-sectional view schematically showing a probe.

[0030] Figure 3 It is shown Figure 2 Cross-sectional view along line III-III.

[0031] Figure 4A This is a cross-sectional view showing the “horizontal” arrangement of the ejection outlets in “Analysis 2” described later.

[0032] Figure 4B This is a cross-sectional view showing the arrangement of the "lower" of the ejection outlets in "Analysis 2" described later.

[0033] Figure 4C It is a cross-sectional view showing the arrangement of the ejection outlets "Y" in "Analysis 2" described later.

[0034] Figure 4D This is a cross-sectional view showing the “inverted Y” arrangement of the ejection outlets described later in “Analysis 2”.

[0035] Figure 5 It is a graph showing the relationship between the cold air-exhaust gas momentum ratio and the temperature deviation of the outlet cross section of the probe.

[0036] Figure 6 It is a diagram showing the relationship between the cold air-exhaust gas momentum ratio and the cold air-exhaust gas wind speed ratio / probe diameter.

[0037] Figure 7 1 is an overall structural diagram showing a second embodiment of a chlorine bypass system including a combustion gas extraction probe according to the present invention.

[0038] Figure 8 2 is a cross-sectional view schematically showing a probe.

[0039] Fig. 9 It is shown Figure 8 Cross-sectional view of line IX-IX.

[0040] Fig. 10A is a cross-sectional view showing a probe used for simulation analysis.

[0041] Fig. 10B is a cross-sectional view showing a probe used for simulation analysis.

[0042] Fig.11 It is a graph showing the relationship between the cold air-exhaust gas momentum ratio and the temperature deviation of the outlet cross section of the probe.

[0043] Fig. 12A It is a cross-sectional view showing a probe according to another embodiment.

[0044] Fig. 12B It is a cross-sectional view showing a probe according to another embodiment.

[0045] Fig. 12C It is a cross-sectional view showing a probe according to another embodiment. DETAILED DESCRIPTION

[0046] [First embodiment]

[0047] Below, refer to Figure 1 to Figure 3 A first embodiment of the combustion gas extraction probe and the operating method thereof according to the present invention will be described. In addition, in each figure, the dimension ratio of the figure is not necessarily consistent with the actual dimension ratio, and the dimension ratio between each figure is not necessarily consistent.

[0048] Figure 11 is a schematic diagram showing the overall structure of a first embodiment of a chlorine bypass system including a combustion gas extraction probe of the present invention. The chlorine bypass system 100 comprises: a probe 2 for extracting a portion of the combustion gas G1 from the kiln exhaust flow passage from the kiln tail 1a of the kiln 1 to the lowest cyclone separator (not shown); a cold air blower 3 for supplying cold air C (equivalent to low-temperature gas) to the probe 2; an inverter 4 for adjusting the output power of the cold air blower 3; a cyclone separator 5 as a classifier for separating the coarse powder A1 contained in the mixed gas G3 obtained by mixing the extraction gas G2 and the cold air C; a cooler 6 for cooling the mixed gas G4 containing the fine powder A2 discharged from the cyclone separator 5; a dust collector 7 for recovering the fine powder A2 from the exhaust gas G5 discharged from the cooler 6; an exhaust fan 8 for guiding the exhaust gas G6 of the dust collector 7; and a measuring instrument 9 (anemometer, thermometer, etc.) for measuring the wind speed of the exhaust fan 8.

[0049] Figure 2 : is a schematic cross-sectional view of the probe 2. The probe 2 is protruding from the kiln tail 1a as a part of the kiln exhaust flow path and facing upward. The inlet 2a of the probe 2 opens in the kiln exhaust flow path in the upright part 1b. The extraction rate of the probe 2 is 5% or more, preferably 10% to 15%. In addition, the extraction rate refers to the gas volume (Nm2) of the exhaust gas G2 extracted per unit time. 3 / per unit time) and the gas volume (Nm 3 / unit time) ratio (ratio).

[0050] In addition, the exhaust volume of the exhaust gas G2 is preferably 2500 Nm 3 / h or more, more preferably 10000Nm 3 / h or more.

[0051] The probe 2 includes: a cylindrical inner tube 21 (equivalent to a gas tube), a cylindrical outer tube 22 surrounding the inner tube 21, a cold air passage 23 formed between the inner tube 21 and the outer tube 22, and a supply port 24 for supplying cold air from the cold air blower 3 to the cold air passage 23. The exhaust gas G2 flows in the inner tube 21 in the direction of the arrow.

[0052] The probe 2 includes a plurality of ejection ports 25 that penetrate the inner tube 21 and eject the cool air C supplied to the cool air passage 23 toward the exhaust gas G2. The ejection ports 25 are formed in a circular shape.

[0053] Figure 3 It is shown Figure 2The view taken along line III-III of the drawing. The plurality of nozzles 25 are arranged at approximately the same position, preferably at the same position, in the extension direction of the inner tube 21. In other words, the plurality of nozzles 25 are preferably arranged in a plane perpendicular to the extension direction of the inner tube 21. The plurality of nozzles 25 respectively eject the cold air C in a direction that is at right angles to the flow direction of the exhaust gas G2 in the inner tube 21. However, as described later, if the cold air C ejected from each nozzle 25 by the plurality of nozzles 25 can diffuse by colliding with each other, it is not necessary to arrange them at exactly the same position in the extension direction of the inner tube 21.

[0054] In the present embodiment, the two jet ports 25 are arranged at line-symmetrical positions with the vertical line P passing through the center O of the inner tube 21 as the axis of symmetry. The two jet ports 25 are respectively arranged on the left and right in such a manner that the angle formed by the straight line L connecting the center 25c of the jet port 25 and the center O of the inner tube 21 and the horizontal line H passing through the center O of the inner tube 21 is 15°. The two jet ports 25 respectively eject cold air C toward the center O of the inner tube 21. In other words, the two jet ports 25 respectively eject cold air C in the direction of the center of the flow of the exhaust gas G2 in the inner tube 21. Therefore, the cold air C ejected from the two jet ports 25 collide with each other near the center O of the inner tube 21 and diffuse. As a result, the cold air C and the exhaust gas G2 can be fully mixed.

[0055] On the other hand, the cold wind C after the collision also has a velocity vector in the direction opposite to the flow direction of the exhaust gas G2, that is, in the direction toward the kiln tail 1a. If the air volume of the cold wind C toward the kiln tail 1a becomes too large, the cold wind C will flow back to the kiln tail 1a, which may become the main cause of heat loss.

[0056] The chlorine bypass system 100 includes a control unit (not shown). The control unit can grasp the air volume and momentum of the exhaust gas G2 in real time based on the exhaust air volume calculated from the measurement value of the measuring device 9 and the cold air volume ejected from the cold air blower 3, and can stably operate the cold air blower 3 at the most suitable output power by controlling the inverter 4.

[0057] In addition, in this specification, the momentum (per unit time) of a gas is defined as follows.

[0058] Momentum of gas [kg·m / s 2 ] = density [kg / m 3 ]×wind speed[m / s]×wind volume[m 3 / s]

[0059] The control unit sets the ratio (MC / MG) of the momentum MC of the cold air C calculated based on the wind speed, wind volume and temperature of the cold air C at each outlet 25 to the momentum MG of the exhaust gas G2 calculated based on the wind speed, wind volume and temperature of the exhaust gas G2 at the inlet 2a of the probe 2 in the range of 1.2 to 4.0, and sets the value [m -1 ] is in the range of 1.5 to 3.5, and the output power of the cooling fan 3 is adjusted. Thus, even when the extraction rate is increased, the extraction gas G2 can be sufficiently cooled, and operation at a predetermined dechlorination efficiency can be maintained (for details, refer to Example 1 described later).

[0060] If the momentum ratio (MC / MG) is excessively reduced, the momentum MC of the cold air C becomes smaller than the momentum MG of the exhaust gas G2, making it difficult to obtain sufficient mixing with the exhaust gas G2. Therefore, the momentum ratio (MC / MG) is 1.2 or more, preferably 3.0 or more.

[0061] On the other hand, if the momentum ratio (MC / MG) is excessively increased, the pressure loss increases and the cooling air blower 3 needs to be enlarged. In addition, as the momentum ratio (MC / MG) increases, the reduction ratio of the temperature deviation (see the following description for details) of the outlet cross section 2b of the probe 2 decreases; on the other hand, the amount of cold air that flows back in the probe 2 and reaches the kiln tail 1a increases. Therefore, the momentum ratio (MC / MG) is 4.0 or less, preferably 3.6 or less.

[0062] If the ratio of wind speed / probe diameter (VC / VG / D) is excessively reduced, the cold air C flows toward the cyclone separator 5 through the exhaust gas G2 before collision diffusion, and it becomes difficult to obtain sufficient mixing. Therefore, the ratio of wind speed / probe diameter (VC / VG / D) is preferably 1.5 or more, and more preferably 2.3 or more.

[0063] If the ratio of wind speed / probe diameter (VC / VG / D) is excessively increased, the pressure loss increases and the cooling air blower 3 needs to be enlarged. In addition, the amount of cold air that flows back in the probe 2 and reaches the kiln tail 1a increases. Therefore, the ratio of wind speed / probe diameter (VC / VG / D) is preferably 3.5 or less, and more preferably 3.0 or less.

[0064] The wind speed VC of the cold wind C is preferably 25 to 180 m / s, more preferably 50 to 150 m / s.

[0065] Alternatively, a variable nozzle (not shown) that varies the opening area of ​​the discharge port 25 may be provided to increase the momentum ratio (MC / MG) by increasing only the wind speed VC while maintaining the air volume of the cold air C.

[0066] Example 1

[0067] In order to explain the present invention in further detail, specific examples and the like are shown below, but the present invention is not limited to the embodiments of these examples.

[0068] The inventors have explored factors that contribute to improving the cooling efficiency of the exhaust gas G2 by simulating and analyzing the mixing state of the exhaust gas G2 and the cold air C. The software used for the simulation analysis is Fluent 2020R2 produced by ANSYS. The exhaust rate of the chlorine bypass system 100 is set to 5% to 15%. In addition, the cold air C is set to 20°C and the outlet cross section 2b of the probe 2 (see Figure 2 ) was introduced so that the average temperature of the air flow chamber 20 was 400° C. By adjusting the area of ​​the air outlet 25 under each condition, the speed of the cold air C was changed while maintaining a predetermined air volume.

[0069] (Analysis 1)

[0070] The temperature distribution in the probe 2 was evaluated after changing the air extraction rate, the wind speed of the cold air C (in Table 1, marked as "cold air speed"), and the probe diameter D. The shape of the probe 2 used for the simulation analysis is Figure 2 and Figure 3 The shape shown in . In addition, the analysis conditions are shown in Table 1. The analysis was carried out in the range of 5% to 15% of the extraction rate and 28 to 200 m / s of the cold wind speed. In addition, the size of the probe 2 was set according to the ratio of the momentum of the cold wind C to the extraction gas G2 (MC / MG), etc., and the analysis examples 1-1 to 3-2 were set as type A, the analysis examples 4-1 to 4-4 were expanded to 1.5 times the cross-sectional area of ​​type A, and the analysis examples 5-1 to 5-2 were reduced to 0.5 times the cross-sectional area of ​​type A. In Table 1, "cold wind-extraction gas momentum ratio" means the ratio of the momentum MC of the cold wind C at each outlet 25 to the momentum MG of the extraction gas G2 (MC / MG); "cold wind-extraction gas wind speed ratio / probe diameter" means the ratio of the wind speed VC of the cold wind C to the wind speed VG of the extraction gas G2 / probe diameter D (VC / VG / D) (the same applies to Tables 2 to 4 described later).

[0071] (Analysis 2)

[0072] For the above-mentioned A-type probe 2, the arrangement and number of the ejection ports 25 were changed. The analysis conditions are shown in Table 2. Figure 4A to Figure 4D The configuration of the ejection outlet 25 is shown in Table 2. In Table 2, "horizontal" indicates that the ejection outlet 25 is Figure 4A In the case of the configuration of "lower", the ejection port 25 is Figure 4B In the case of the configuration, "Y" indicates that the ejection port 25 is Figure 4CIn the case of the configuration, "inverted Y" indicates that the ejection port 25 is Figure 4D configuration situation (the same applies to Table 4 described later).

[0073] [Table 1]

[0074]

[0075] [Table 2]

[0076]

[0077] The cold air C is introduced so that the average temperature of the outlet section 2b of the probe 2 becomes 400°C, and from the viewpoint of lowering the temperature of the exhaust gas G2 to below 600-700°C, which is the melting point of chloride (refer to Japanese Patent No. 4294871), the degree of gas cooling is judged by whether the temperature deviation of the outlet section 2b of the probe 2 reaches below 200°C as an evaluation criterion. Here, the temperature deviation of the outlet section 2b of the probe 2 is the deviation from the average temperature in the outlet section 2b.

[0078] Due to the increase in the wind speed of the cold air C, there is a concern that the cold air C may mix into the kiln tail 1a (backflow). Therefore, in order to quantify the amount of cold air that reaches the kiln tail 1a relative to the amount of cold air, the amount of cold air that reaches the kiln tail 1a relative to the amount of cold air is calculated based on the temperature drop at the junction (inlet 2a) between the probe 2 and the kiln tail 1a (the difference from the temperature of the kiln tail 1a), and the backflow rate of the introduced cold air C is calculated. The backflow rate can be regarded as one of the indicators of the force of the ejected cold air C colliding and diffusing. If the value is high, it means that the mixing force of the cold air C in the probe 2 is strong. In the fluid simulation, almost all of the cold air C that has reached the kiln tail 1a flows back to the probe 2 side; on the other hand, if the amount is too large, the cold air C passes through the kiln tail 1a and may become the main cause of heat loss. Therefore, it is hoped to suppress the backflow rate as much as possible, and in this analysis, the backflow rate is set below 10%.

[0079] Table 3 shows the temperature deviation and the backflow rate of the outlet section 2b of the probe 2 in the analysis 1. In Table 3, "○" indicates that the temperature deviation of the outlet section 2b of the probe 2 is less than 200°C and the backflow rate is less than 10%; "×" indicates that the temperature deviation of the outlet section 2b of the probe 2 exceeds 200°C or the backflow rate exceeds 10%.

[0080] [Table 3]

[0081]

[0082] The temperature deviation decreases with the increase of the momentum ratio of cold air to exhaust gas, and the temperature deviation tends to decrease even when the exhaust rate is 15% and the probe diameter is different.

[0083] exist Figure 5 The figure shows the relationship between the momentum ratio of the cold air to the exhaust gas in "Analysis 1" and the temperature deviation of the outlet cross section 2b of the probe 2. The blank circles are the conditions that are judged as "×", and the black circles are the conditions that are judged as "○" ( Figure 6 The same is true in FIG. 2 ). The correlation between the cold air-exhaust gas momentum ratio and the temperature deviation of the outlet cross section 2b of the probe 2 was confirmed to be independent of the extraction rate and the size of the probe diameter D. On the other hand, the operating conditions cannot be determined solely based on the cold air-exhaust gas momentum ratio.

[0084] Therefore, the present inventors used indices including wind speed and probe diameter D as factors related to the collision of the cold wind C in addition to the cold wind-exhaust gas momentum ratio to make a judgment. Figure 6 The results are shown in Figure 6 As shown in the figure, if the momentum ratio of cold air to exhaust gas is 1.2-4.0 and the wind speed ratio of cold air to exhaust gas / probe diameter (m -1 ) is in the range of 1.5 to 3.5, the temperature deviation of the outlet cross section 2b of the probe 2 is 200°C or less regardless of the pumping rate and the probe diameter D. Therefore, by using this index, sufficient cooling performance of the chlorine bypass system can be easily achieved even in different chlorine bypass systems.

[0085] Table 4 shows the temperature deviation of the outlet cross section 2b of the probe 2 in "Analysis 2". In Table 4, "○" indicates a case where the backflow rate is 10% or less, and "×" indicates a case where the backflow rate exceeds 10%.

[0086] [Table 4]

[0087]

[0088] Regardless of the configuration of the ejection port 25, as the momentum ratio of cold air to exhaust gas increases, the temperature deviation of the outlet cross section 2b of the probe 2 tends to decrease. Therefore, regardless of the configuration of the ejection port 25, by controlling the momentum ratio of cold air to exhaust gas, a predetermined cooling performance can be achieved. In addition, when the ejection port 25 is configured "horizontally", the cooling performance is highest. That is, the plurality of ejection ports 25 preferably include a pair of (paired) ejection ports 25 that are relatively arranged on both sides of the inner tube 21 in the horizontal direction and eject the cold air C in the horizontal direction. It can be considered that: when the cold air C ejected in the horizontal direction from a pair of ejection ports 25 relatively arranged on both sides in the horizontal direction collide head-on with each other, the cold air C is difficult to deflect in the upward and downward directions, and the cooling performance is high.

[0089] As described above, the probe 2 of the present embodiment comprises: an inner tube 21 for exhausting a portion of the combustion gas G1 from the kiln 1; and a plurality of nozzles 25 penetrating the inner tube 21 for respectively ejecting the cold air C in a direction perpendicular to the flow direction of the exhaust gas G2 exhausted from the inner tube 21 and in a direction toward the center of the flow of the exhaust gas G2, the nozzles 25 ejecting the cold air C in such a manner that the ratio of the momentum MC of the cold air C at each nozzle of the nozzle 25 to the momentum MG of the exhaust gas G2 (MC / MG) satisfies 1.2 to 4.0 and the ratio of the wind speed VC of the cold air C to the wind speed VG of the exhaust gas G2 (VC / VG) is divided by the probe diameter D of the inner tube 21 (m -1 ) is sprayed in a manner that satisfies 1.5 to 3.5.

[0090] Based on the above-described structure, even when the extraction rate is increased, the extraction gas G2 can be sufficiently cooled and operation while maintaining a prescribed chlorine removal efficiency is enabled.

[0091] In the probe 2 of the present embodiment, the plurality of outlets 25 preferably include a pair of outlets 25 that are disposed opposite to each other on both sides of the inner tube 21 in the horizontal direction and that eject the cold air C in the horizontal direction.

[0092] Based on the above structure, good cooling performance can be achieved.

[0093] In the probe 2 of the present embodiment, it is preferable that the wind speed VC of the cold wind C is 25 to 180 m / s.

[0094] Based on the above structure, good cooling performance can be achieved.

[0095] In addition, in the probe 2 of the present embodiment, it is preferred that the cold air C ejected from the plurality of outlets 25 have a velocity vector in a direction opposite to the flow direction of the exhaust gas G2 after colliding with each other, and the ratio of the cold air C flowing back to the kiln tail 1a to the ejected cold air C is less than 10%.

[0096] The above-described structure can suppress the backflow rate to a low level, thereby suppressing heat loss.

[0097] In addition, the operating method of the probe 2 of the present embodiment, wherein the probe 2 comprises: an inner tube 21 for exhausting a portion of the combustion gas G1 from the kiln 1; and a plurality of nozzles 25, which are arranged through the inner tube 21, and respectively eject the cold air C in a direction perpendicular to the flow direction of the exhaust gas G2 exhausted by the inner tube 21 and in a direction toward the center of the flow of the exhaust gas G2; in the operating method, the ratio of the momentum MC of the cold air C at each nozzle 25 to the momentum MG of the exhaust gas G2 (MC / MG) satisfies 1.2 to 4.0, and the value obtained by dividing the ratio of the wind speed VC of the cold air C to the wind speed VG of the exhaust gas G2 (VC / VG) by the probe diameter D of the inner tube 21 (m -1 ) satisfies 1.5~3.5.

[0098] According to the above-described structure, even when the extraction rate is increased, the extraction gas G2 can be sufficiently cooled, and operation while maintaining a predetermined chlorine removal efficiency is enabled.

[0099] In addition, the combustion gas extraction probe and its operation method are not limited to the structure of the above-mentioned embodiment, and are not limited to the above-mentioned effects. In addition, various changes can be made to the combustion gas extraction probe without departing from the scope of the present invention. For example, various structures, various methods, etc. of the above-mentioned multiple embodiments can be arbitrarily adopted and combined. In addition, of course, one or more of the following various modified examples of structures, methods, etc. can be arbitrarily selected for the structures, methods, etc. of the above-mentioned embodiments.

[0100] In the probe 2 of the above embodiment, the two ejection ports 25 are provided through the inner tube 21. However, the probe 2 is not limited to such a structure. Figure 4A As shown, the inner tube 21 may be provided with three or more discharge ports 25. When three or more discharge ports 25 are provided, they are preferably arranged at equal intervals in the circumferential direction of the inner tube 21.

[0101] [Second embodiment]

[0102] Below, refer to Figure 7 to Figure 9 A second embodiment of the combustion gas extraction probe and the operating method thereof according to the present invention will be described. In addition, in each figure, the dimension ratio of the figure is not necessarily consistent with the actual dimension ratio, and the dimension ratio between each figure is not necessarily consistent.

[0103] Figure 71 is a schematic diagram showing the overall structure of a second embodiment of a chlorine bypass system including a combustion gas extraction probe of the present invention. The chlorine bypass system 100 comprises: a probe 2 for extracting a portion of the combustion gas G1 from the kiln exhaust flow passage from the kiln tail 1a of the kiln 1 to the lowest cyclone separator (not shown); a cold air blower 3 for supplying cold air C (equivalent to low-temperature gas) to the probe 2; a cyclone separator 5 as a classifier for separating the coarse powder A1 contained in the mixed gas G3 obtained by mixing the extraction gas G2 and the cold air C; a cooler 6 for cooling the mixed gas G4 containing the fine powder A2 discharged from the cyclone separator 5; a dust collector 7 for recovering the fine powder A2 from the exhaust gas G5 discharged from the cooler 6; and an exhaust blower 8 for guiding the exhaust gas G6 of the dust collector 7.

[0104] Figure 8 : is a schematic cross-sectional view of the probe 2. The probe 2 is protrudingly provided on the rising portion 1b, and the rising portion 1b rises upward from the kiln tail 1a as a part of the kiln exhaust flow path. The inlet 2a of the probe 2 opens into the kiln exhaust flow path in the rising portion 1b. The extraction rate of the probe 2 is 10% or more, preferably 12% or more, and more preferably 15% or more. In addition, the extraction rate refers to the gas volume (Nm2) of the exhaust gas G2 extracted per unit time. 3 / per unit time) and the gas volume (Nm 3 / unit time) ratio (ratio).

[0105] In addition, the exhaust volume of the exhaust gas G2 is preferably 2500 Nm 3 / h or more, more preferably 10000Nm 3 / h or more.

[0106] The probe 2 includes: a cylindrical inner tube 21 (equivalent to a gas tube), a cylindrical outer tube 22 surrounding the inner tube 21, a cold air passage 23 formed between the inner tube 21 and the outer tube 22, and a supply port 24 for supplying cold air from the cold air blower 3 to the cold air passage 23. The exhaust gas G2 flows in the inner tube 21 in the direction of the arrow.

[0107] The probe 2 includes a plurality of ejection ports 250 that penetrate the inner tube 21 and eject the cool air C supplied to the cool air passage 23 toward the exhaust gas G2. The ejection ports 250 are formed in a circular shape.

[0108] Fig. 9 It is shown Figure 8The plurality of ejection ports 250 are arranged at substantially the same position, preferably at the same position, in the extension direction of the inner tube 21. In other words, the plurality of ejection ports 250 are preferably arranged in a plane perpendicular to the extension direction of the inner tube 21. However, the plurality of ejection ports 250 do not need to be arranged at exactly the same position in the extension direction of the inner tube 21.

[0109] In the present embodiment, the two ejection ports 250 are arranged point-symmetrically with the center O of the inner tube 21 as the center of symmetry. The two ejection ports 250 are arranged in a manner shifted by 180 degrees from each other in the circumferential direction of the inner tube 21 .

[0110] The ejection ports 250 are arranged in such a manner that the center 250c is formed parallel to the horizontal line H. The two ejection ports 250 eject the cold air C toward the exhaust gas G2 in the inner tube 21, respectively. That is, the two ejection ports 250 are alternately arranged, and the cold air C ejected from each ejection port 250 does not collide with each other in the inner tube 21. Thus, the cold air C ejected from each ejection port 250 diffuses without colliding with each other, and it is difficult to generate a flow in the direction toward the kiln tail 1a side. As a result, it is possible to suppress the cold air C from flowing back to the kiln tail 1a, and it is possible to suppress heat loss.

[0111] The inner tube 21 preferably has a nozzle 260 surrounding the ejection port 250. The cylindrical nozzle 260 is arranged coaxially with the center 250c of the ejection port 250. By providing the nozzle 260 around the ejection port 250, the cold air C is ejected in a direction along the center 250c of the ejection port 250. In addition, when the wall thickness of the inner tube 21 is sufficiently large, the nozzle 260 is not necessarily required.

[0112] The chlorine bypass system 100 includes a control unit (not shown). The control unit can adjust the output power of the cold air blower 3.

[0113] The control unit adjusts the output power of the cold air blower 3 so that the ratio (MC / MG) of the momentum MC of the cold air C calculated based on the wind speed, wind volume and temperature of the cold air C at each outlet 250 and the momentum MG of the exhaust gas G2 calculated based on the wind speed, wind volume and temperature of the exhaust gas G2 at the inlet 2a of the probe 2 is within the range of 1.8 to 5.3. Thus, even when the exhaust rate is increased, the exhaust gas G2 can be sufficiently cooled, and it is possible to maintain the operation of the specified dechlorination efficiency (refer to Example 2 described later for details).

[0114] In addition, in this specification, the momentum (per unit time) of a gas is defined as follows.

[0115] Momentum of gas [kg·m / s 2 ] = density [kg / m 3]×wind speed[m / s]×wind volume[m 3 / s]

[0116] If the momentum ratio (MC / MG) is excessively reduced, the momentum MC of the cold air C becomes smaller than the momentum MG of the exhaust gas G2, making it difficult to obtain sufficient mixing with the exhaust gas G2. Therefore, the momentum ratio (MC / MG) is 1.8 or more, preferably 3.0 or more.

[0117] On the other hand, if the momentum ratio (MC / MG) is excessively increased, the pressure loss increases and the cooling fan 3 needs to be enlarged. In addition, as the momentum ratio (MC / MG) increases, the reduction ratio of the temperature deviation (described later) of the outlet cross section 2b of the probe 2 decreases; on the other hand, the amount of cold air that flows back in the probe 2 and reaches the kiln tail 1a increases. Therefore, the momentum ratio (MC / MG) is 5.3 or less, preferably 4.0 or less.

[0118] The wind speed of the cold wind C is preferably 25 to 180 m / s, more preferably 50 to 150 m / s.

[0119] Alternatively, a variable nozzle (not shown) that changes the opening area of ​​the discharge port 250 may be provided to increase the momentum ratio (MC / MG) by increasing only the wind speed while maintaining the air volume of the cold air C.

[0120] Example 2

[0121] In order to further explain the present invention in detail, specific examples and the like are shown below, but the present invention is not limited to the embodiments of these examples.

[0122] The present inventors have confirmed the effect of the arrangement of the plurality of ejection ports 250 by simulation analysis of the mixing state of the exhaust gas G2 and the cold air C. The software used for the simulation analysis is Fluent 2020R2 produced by ANSYS.

[0123] Fig. 10A and Fig. 10B 2 shows the cross-sectional shape of the probe used for the simulation analysis (in addition, the outer tube 22 is not shown). Fig. 10A An example of a pair of ejection ports 250 is shown, which are configured to eject the cold air C in directions perpendicular to the flow direction of the exhaust gas G2 extracted from the inner tube 21 and the ejected cold air C does not collide with each other in the inner tube 21 . Fig. 10B An example of a pair of ejection ports 250A is shown, and the pair of ejection ports 250A are arranged to eject the cold air C in a direction perpendicular to the flow direction of the exhaust gas G2 extracted from the inner tube 21 and in a direction toward the center of the flow of the exhaust gas G2.

[0124] The analysis conditions are shown in Table 5. The extraction rate in the chlorine bypass system 100 was set to 10% to 15%. In addition, the cold air C was set to 20°C, the outlet cross section 2b of the probe 2 (see Figure 2 ) was introduced so that the average temperature of the air flow chamber 250 was 400° C. Under each condition, the speed of the cold air C was changed while maintaining a predetermined air volume by adjusting the area of ​​the air outlets 250 and 250A.

[0125] Regarding the wind speed of the cold air C, the ratio of the momentum of the cold air C calculated based on the wind speed, air volume and temperature of the cold air C at each outlet 250, 250A to the momentum of the exhaust gas G2 calculated based on the wind speed, air volume and temperature of the exhaust gas G2 at the inlet 2a of the probe 2 is set and analyzed.

[0126] In Table 5, "cold air speed" means the wind speed of the cold air C, and "cold air-exhaust gas momentum ratio" means the ratio (MC / MG) of the momentum MC of the cold air C at each of the outlets 250 and 250A to the momentum MG of the exhaust gas G2 (the same applies to Table 6 described later). In addition, in Table 5, "alternating type" means whether the outlet is Fig. 10A The configuration shown in the figure is “collision type”, which means that the nozzle is Fig. 10B The configuration shown in .

[0127] [Table 5]

[0128]

[0129] The cold air C is introduced so that the average temperature of the outlet section 2b of the probe 2 becomes 400°C. From the viewpoint of lowering the temperature of the exhaust gas G2 to below 600-700°C, which is the melting point of chloride (refer to Japanese Patent Gazette No. 4294871), the degree of gas cooling is judged by whether the temperature deviation of the outlet section 2b of the probe 2 reaches below 200°C. Here, the temperature deviation of the outlet section 2b of the probe 2 is the deviation from the average temperature in the outlet section 2b.

[0130] In addition, the ratio of the cold air C reaching the inlet 2a of the probe 2 was calculated based on the temperature drop at the junction (inlet 2a) between the probe 2 and the kiln tail 1a (the difference from the temperature of the kiln tail 1a), and the backflow rate of the introduced cold air C was evaluated. Table 6 shows the temperature deviation of the outlet section 2b of the probe 2 and the backflow rate to the kiln tail 1a. In Table 6, "○" indicates a case where the backflow rate is 0, "△" indicates a case where the backflow rate is less than 10%, and "×" indicates a case where the backflow rate exceeds 10%.

[0131] [Table 6]

[0132]

[0133] In the "alternating type" of Analysis Examples 6-1 to 7-2, the temperature deviation was slightly higher than that of the "collision type" of Analysis Examples 8-1 to 9-2 under the same conditions, and the temperature deviation was 200° C. or less, indicating sufficient cooling.

[0134] In addition, in the "alternating type" of analysis examples 6-1 to 7-2, no backflow to the kiln tail 1a occurs. The reason is that in the "collision type", the cold air C ejected from the plurality of ejection ports 250A respectively generates a velocity vector to the kiln tail 1a side after colliding with each other, but in the "alternating type", there is no direct collision between the cold air C, so the amount of velocity vector generated to the kiln tail 1a side is small.

[0135] Fig.11 The relationship between the cold air-exhaust gas momentum ratio and the temperature deviation of the outlet section 2b of the probe 2 is shown in FIG. Fig.11 As shown, when the momentum ratio of the cold wind to the exhaust gas is in the range of 1.8 to 5.3, and when it is in the range of 3.0 to 4.0, the temperature of the exhaust gas G2 in the probe 2 can be made uniform at an earlier stage.

[0136] As described above, the probe 2 of the present embodiment comprises: an inner tube 21 for exhausting a portion of the combustion gas G1 from the kiln 1; and a plurality of nozzles 250 which are penetrated through the inner tube 21 and respectively eject the exhaust gas G2 which is exhausted by the cold air C relative to the inner tube 21. The plurality of nozzles 250 are arranged so that the cold air C ejected from each nozzle 250 does not collide with each other in the inner tube 21.

[0137] Based on the above structure, the cold air C ejected from each ejection port 250 does not collide with each other and diffuses, and it is difficult to generate a flow toward the kiln tail 1a side. Therefore, even when the extraction rate is increased, the extraction gas G2 can be sufficiently cooled, and the backflow of the cold air C to the kiln tail 1a can be suppressed.

[0138] In addition, in the probe 2 of the present embodiment, it is preferable that the plurality of ejection ports 250 are arranged at the same position in the extending direction of the inner tube 21 .

[0139] Based on the above structure, good cooling performance can be achieved.

[0140] In the probe 2 of the present embodiment, it is preferable that the plurality of ejection ports 250 are symmetrically arranged with the center O of the inner tube 21 as a center point of symmetry when viewed in the extending direction of the inner tube 21 .

[0141] Based on the above structure, good cooling performance can be achieved.

[0142] In the probe 2 of the present embodiment, it is preferable that the plurality of ejection ports 250 are arranged at equal intervals in the circumferential direction of the inner tube 21 .

[0143] Based on the above structure, good cooling performance can be achieved.

[0144] In addition, in the operation method of the probe 2 of this embodiment, the wind speed of the cold air C ejected from the ejection port 250 satisfies 25 to 180 m / s, and the ratio (MC / MG) of the momentum MC of the cold air C at each ejection port 250 to the momentum MG of the exhaust gas G2 satisfies 1.8 to 5.3.

[0145] Based on the above structure, even when the exhaust rate is increased, the exhaust gas G2 can be sufficiently cooled, and the backflow of the cold air C to the kiln tail 1a can be suppressed.

[0146] In the operating method of the probe 2 of the present embodiment, it is preferable that the cold air C does not flow back toward the kiln tail 1 a after colliding with the inner wall surface of the inner tube 21 .

[0147] The above-described structure can suppress the backflow rate to be low.

[0148] In addition, the combustion gas extraction probe and its operation method are not limited to the structure of the above-mentioned embodiment, nor are they limited to the above-mentioned effects. In addition, various changes can be made to the combustion gas extraction probe within the scope of the present invention. For example, of course, various structures, various methods, etc. of the above-mentioned multiple embodiments can be arbitrarily adopted and combined, and one or more structures, methods, etc. of the following various modified examples can be arbitrarily selected for the structures, methods, etc. of the above-mentioned embodiments.

[0149] (1) In the probe 2 of the above embodiment, the plurality of ejection ports 250 are arranged at the same position in the extending direction of the inner tube 21. However, the probe 2 is not limited to such a structure. For example, the plurality of ejection ports 250 may be arranged at different positions in the extending direction of the inner tube 21.

[0150] (2) In the probe 2 of the present embodiment, the plurality of ejection ports 250 are arranged point-symmetrically with the center O of the inner tube 21 as the center of symmetry when viewed in the extending direction of the inner tube 21. However, the probe 2 is not limited to such a structure. Fig. 12A and Fig. 12B As shown, when viewed in the extending direction of the inner tube 21 , the plurality of ejection ports 250 are not arranged point-symmetrically with the center O of the inner tube 21 as the center of symmetry.

[0151] (3) In the probe 2 of the present embodiment, the two ejection ports 250 are arranged at equal intervals in the circumferential direction of the inner tube 21. However, the probe 2 is not limited to such a structure. Fig. 12C As shown, three ejection ports 250 are arranged at equal intervals in the circumferential direction of the inner tube 21 .

[0152] Description of Reference Numerals

[0153] 1: Kiln G1: Combustion gas

[0154] 1a: Kiln tail (kiln tail) G2: exhaust gas

[0155] 1b: Rising part G3: Mixed gas

[0156] 2: Probe G4: Mixed gas

[0157] 2a: Inlet of the probe G5: Exhaust (waste gas)

[0158] 2b: Probe outlet profile G6: Exhaust (waste gas)

[0159] 3: Cold air fan H: Horizontal line

[0160] 4: Inverter MC: Momentum of cold wind

[0161] 5: Cyclone separator MG: Momentum of the extracted gas 6: Cooler O: Center of inner tube

[0162] 7: Dust collection device VC: wind speed of cold air

[0163] 8: Exhaust fan VG: wind speed of the exhaust gas 9: Measuring device

[0164] 21: Inner tube

[0165] 22: External pipe

[0166] 23: Cold air channel

[0167] 24: Supply port

[0168] 25: Spout

[0169] 25c: Center of the vent

[0170] 250: Spout

[0171] 250c: Center of the spray port

[0172] 260: Nozzle

[0173] 100: Chlorine Bypass System

[0174] A1: Coarse powder

[0175] A2: Micro powder

[0176] C: Cold wind

[0177] D: Probe diameter

Claims

1. A combustion gas extraction probe, characterized in that: The combustion gas extraction probe has: a gas pipe to extract part of the combustion gases from the kiln; and A plurality of ejection ports are provided through the gas pipe, and respectively eject the low-temperature gas in a direction perpendicular to the flow direction of the exhaust gas being exhausted by the gas pipe and in a direction toward the center of the flow of the exhaust gas, and the ejection ports eject the low-temperature gas in such a manner that the ratio of the momentum of the low-temperature gas at each of the ejection ports to the momentum of the exhaust gas satisfies 1.2 to 4.0, and the ratio of the wind speed of the low-temperature gas to the wind speed of the exhaust gas divided by the inner diameter of the gas pipe satisfies 1.5 m -1 ~3.5m -1 way of spraying out.

2. The combustion gas extraction probe according to claim 1, characterized in that: The plurality of ejection ports include a pair of ejection ports that are disposed opposite to each other on both sides of the gas pipe in a horizontal direction and eject the low-temperature gas in a horizontal direction.

3. The combustion gas extraction probe according to claim 1, characterized in that: The wind speed of the low-temperature gas is 25m / s to 180m / s.

4. The combustion gas extraction probe according to claim 1, characterized in that: The low-temperature gases ejected from the plurality of ejection ports have a velocity vector in a direction opposite to the flow direction of the exhaust gas after colliding with each other. The ratio of the low-temperature gas flowing back to the kiln tail to the low-temperature gas ejected is less than 10%.

5. A method for operating a combustion gas extraction probe, characterized in that: The combustion gas extraction probe has: a gas pipe to extract part of the combustion gases from the kiln; and A plurality of ejection ports are provided through the gas pipe, and the low-temperature gas is ejected in a direction perpendicular to the flow direction of the exhaust gas being exhausted by the gas pipe and in a direction toward the center of the flow of the exhaust gas. In the operation method, the ratio of the momentum of the low-temperature gas at each of the ejection ports to the momentum of the exhaust gas satisfies 1.2 to 4.0, and the value obtained by dividing the ratio of the wind speed of the low-temperature gas to the wind speed of the exhaust gas by the inner diameter of the gas pipe satisfies 1.5 m -1 ~3.5m -1 .

6. A combustion gas extraction probe, characterized in that: The combustion gas extraction probe has: a gas pipe to extract part of the combustion gases from the kiln; and A plurality of ejection ports are provided through the gas pipe to eject the exhaust gas extracted from the gas pipe using the low-temperature gas. The plurality of ejection ports are arranged in such a manner that the low-temperature gases ejected from the respective ejection ports do not collide with each other in the gas pipe. The wind speed of the low-temperature gas ejected from the ejection port satisfies 25 m / s to 180 m / s, and the ratio of the momentum of the low-temperature gas at each outlet of the ejection port to the momentum of the exhaust gas satisfies 1.8 to 5.

3.

7. The combustion gas extraction probe according to claim 6, characterized in that: The plurality of ejection ports are arranged at the same position in the extending direction of the gas pipe.

8. The combustion gas extraction probe according to claim 6, characterized in that: When viewed in the extending direction of the gas pipe, the plurality of ejection ports are arranged in point symmetry with the center of the gas pipe as the center of symmetry.

9. The combustion gas extraction probe according to claim 6, characterized in that: The plurality of ejection ports are arranged at equal intervals in a circumferential direction of the gas pipe.

10. A method for operating a combustion gas extraction probe, characterized in that: The combustion gas extraction probe has: a gas pipe to extract part of the combustion gases from the kiln; and A plurality of ejection ports are provided through the gas pipe to eject the exhaust gas extracted from the gas pipe using the low-temperature gas. The plurality of ejection ports are arranged in such a manner that the low-temperature gases ejected from the respective ejection ports do not collide with each other in the gas pipe. In the operation method, the wind speed of the low-temperature gas ejected from the ejection port satisfies 25m / s to 180m / s, and the ratio of the momentum of the low-temperature gas at each outlet of the ejection port to the momentum of the exhaust gas satisfies 1.8 to 5.

3.

11. The method for operating the combustion gas extraction probe according to claim 10, characterized in that: The low-temperature gas does not flow back toward the kiln tail after colliding with the inner wall surface of the gas pipe.

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