JP5290099B2 - Gas mixing device and operation method thereof - Google Patents

Description

  The present invention relates to a gas mixing device and a method for operating the same, and in particular, a gas used in a cement kiln chlorine bypass facility for extracting chlorine by extracting a part of combustion gas from a kiln bottom of a cement kiln and the like. The present invention relates to a mixing device and the like.

  In the past, it was noted that chlorine was a particular problem among chlorine, sulfur, alkali, etc. that would cause problems such as blockage of preheaters in cement production facilities. Chlorine bypass equipment is used to extract some of the chlorine and remove chlorine. In addition, with the recent increase in the amount of chlorine-containing recycled resources used, the amount of chlorine brought into the cement kiln has increased, making it impossible to increase the capacity of the chlorine bypass facility.

  In this chlorine bypass facility, in order to extract a part of the combustion gas from the vicinity of the inlet hood, a probe projects from the vicinity of the inlet hood, and an extraction gas processing facility is provided downstream of the probe. Since the tip of the probe is exposed to a high temperature of about 1000 ° C. near the inlet hood, it is necessary to use cast steel having a high heat resistance or to cool the probe with cold air taken from the outside of the inlet hood to protect the probe. .

  In addition, volatile components such as chlorine in the kiln exhaust gas are concentrated to a fine part of the bypass dust by rapidly cooling to about 450 ° C. or less with a probe. The bypass dust is classified into coarse dust with low volatile component concentration and fine dust with high volatile component concentration. The coarse dust is returned to the kiln system, and only fine dust is removed from the system via the chlorine bypass facility. By discharging, the amount of bypass dust can be reduced. Therefore, also from this point, it is necessary to quench the kiln exhaust gas at the probe.

  In view of the above points, Patent Document 1 discloses an inner cylinder through which high-temperature combustion gas flows, an outer cylinder that surrounds the inner cylinder, a low-temperature gas outlet formed in the inner cylinder, an inner cylinder, and an outer cylinder. A combustion gas extraction probe comprising low temperature gas supply means for supplying a low temperature gas to a cylinder and discharging a low temperature gas from a discharge port in a central direction perpendicular to a suction direction of the high temperature combustion gas is described. ing.

International Publication WO2005 / 050114 Pamphlet

  However, even when a cross-flow cooled probe having a high chlorine removal capability, such as the combustion gas extraction probe described in Patent Literature 1, is used depending on the installation conditions such as the installation angle of the probe, Dust contained in the combustion gas causes a drift in the probe or in the secondary cooling section, causing wear of the probe and uneven distribution of gas temperature in the probe, leading to shortened probe life and reduced performance. It was. In addition, to prevent probe wear and uneven distribution of gas temperature in the probe, anti-friction plates and anti-current plates have been installed, but the expected effects cannot be obtained. It was.

  Therefore, the present invention has been made in view of the above problems in the prior art, and in a cement kiln chlorine bypass facility or the like, the life of the combustion gas extraction probe and the performance of the probe such as chlorine removal capability are improved. It is an object of the present invention to provide a gas mixing device and the like that can improve the above-mentioned.

  In order to achieve the above object, the present invention comprises a gas pipe and a plurality of discharge ports perforated in the gas pipe, and the first gas flowing in the gas pipe extending direction is provided in the gas pipe. Gas that discharges the second gas from each of the plurality of discharge ports in a direction perpendicular to the center of the first gas and mixes the first gas and the second gas. The vector obtained by combining the momentum vectors of the second gas discharged from each of the plurality of discharge ports is the velocity distribution of the first gas from the center of the cross section of the gas pipe. It has a component opposite to the direction toward the center of gravity.

  And according to this invention, the vector which synthesize | combined the momentum vector of the 2nd gas discharged from each of a some discharge port from the center of the cross section of a gas pipe to the gravity center position of the velocity distribution of the 1st gas Since it is configured to have a component in a direction opposite to the direction in which it goes, the second gas can be supplied in accordance with the degree of drift of the first gas and dust contained in the first gas. In addition, the collision of dust with the inner surface of the gas pipe can be minimized, and the first gas and the second gas can be efficiently mixed in the gas pipe.

  In the gas mixing apparatus, the plurality of discharge ports can be arranged in a plane perpendicular to the extending direction of the gas pipe, wherein the plurality of discharge ports are extended to the gas pipe. Arranged at 2 to 4 locations in a plane perpendicular to the direction, 10% to 50% of the total amount of the second gas can be discharged from each discharge port. As a result, the second gas can be discharged into the gas pipe with a good overall balance, and the first gas and the second gas can be efficiently mixed in the gas pipe. The position of each discharge port can be determined by simulating the mixed state of the first and second gases, and the amount of the second gas discharged from each discharge port is adjusted based on the measurement result in the actual machine. It is preferable to do.

  In the gas mixing apparatus, the plurality of discharge ports are arranged at two locations in a plane perpendicular to the extending direction of the gas pipe, and each of the discharge ports arranged at the two locations is connected to the gas It can arrange | position in the position moved to the gravity center direction of the velocity distribution of said 1st gas from the center of the cross section of a pipe | tube.

  In addition, among the plurality of discharge ports, the center of the discharge port having the largest amount of movement in the center of gravity direction of the velocity distribution of the first gas from the center of the cross section of the gas pipe is the first cross section in the cross section. In the gas velocity distribution, the gas flow distribution can be located within a range that occupies 60% of the entire flow rate across the portion with the highest velocity across the portion with the highest velocity.

  Furthermore, the plurality of discharge ports can be arranged in a plurality of stages with respect to the extending direction of the gas pipe.

  The present invention is also a method for operating each of the gas mixing devices described above, wherein the total flow rate of the second gas or / and the flow rate of the first gas or / and the center of gravity of the velocity distribution. The flow rate of the second gas discharged from each of the plurality of discharge ports is adjusted. Accordingly, the discharge amount of the second gas from the discharge port can be adjusted according to the mixed state in the vicinity of the discharge port, effectively preventing dust drift in the gas pipe, and the first in the gas pipe. The gas and the second gas can be mixed efficiently.

  As described above, according to the present invention, two kinds of gases can be efficiently mixed in a gas pipe, and in a cement kiln chlorine bypass facility or the like, not only in a combustion gas extraction probe but also in a cooling part at a stage downstream of the probe. By improving the cooling efficiency and prolonging the service life by preventing wear, it becomes possible to improve the performance such as chlorine removal capability.

It is a figure which shows the extraction part of the cement kiln chlorine bypass installation using the gas mixing apparatus concerning this invention, Comprising: (a) is a partially broken sectional view, (b) is the sectional view on the AA line of (a). (The drawing is such that the axis L in (a) is perpendicular to the paper surface in FIG. 1 (b)), and (c) is a sectional view taken along the line BB in (a). It is an enlarged view of the secondary cooling part of the extraction part of FIG. 1, Comprising: (a) is a longitudinal cross-sectional view, (b) is a cross-sectional view. It is the schematic for demonstrating the example of arrangement | positioning of the discharge outlet of the combustion gas extraction probe concerning this invention.

  Next, an embodiment for carrying out the present invention will be described in detail with reference to the drawings. In the following description, the gas mixing device according to the present invention is applied to a cement kiln chlorine bypass facility for extracting chlorine by extracting a part of combustion gas from a kiln bottom of a cement kiln. Let's take an example.

  Fig.1 (a) shows the extraction part of the cement kiln chlorine bypass installation to which the gas mixing apparatus concerning this invention is applied, This extraction part 1 is cooling a part of high temperature combustion gas G of a cement kiln. It comprises a probe 2 for extracting air and a secondary cooling unit 4 provided in a duct 3 on the downstream side of the probe 2.

  The probe 2 includes a cylindrical inner cylinder 12, a cylindrical outer cylinder 13 surrounding the inner cylinder 12, a cooling air passage 18 formed between the inner cylinder 12 and the outer cylinder 13, and a cooling fan (not A primary cooling air supply port 19 for supplying primary cooling air from the illustration) to the cooling air passage 18 and the like are provided, and installed on the rising portion 15 of the cement kiln via the mounting seat 14.

  The inner cylinder 12 is provided for extracting the high-temperature combustion gas G flowing through the rising portion 15 in the direction of arrow S while being cooled by the primary cooling air C1 introduced from the discharge port 12b. The inlet 12a of the inner cylinder 12 faces the combustion gas flow path of the rising portion 15 of the cement kiln. Two discharge ports 12b are provided at positions symmetrical with respect to a vertical line P passing through the center O1 of the inner cylinder 12 as an axis of symmetry.

  For example, as shown in FIG. 1B, the discharge port 12b is formed by a straight line L1 connecting the center 12c of the discharge port 12b and the center O1 of the inner cylinder 12 and a horizontal line H passing through the center O1 of the inner cylinder 12. One each is arranged on the left and right so that the angle is 15 °. Such an arrangement is based on a simulation of the temperature distribution inside the probe 2 having a drift of the combustion gas G in the probe 2 (the velocity distribution of the combustion gas G is indicated by reference numeral 31). Thus, the uneven distribution of the gas temperature in the probe 2 is reduced, and the probe 2 can be extracted while efficiently cooling a part of the high-temperature combustion gas G in the cement kiln. It should be noted that the number of attachments of the discharge ports 12b and the attachment position can be changed as appropriate.

  The outer cylinder 13 is formed in a cylindrical shape whose cross section is concentric with the inner cylinder 12 so as to surround the inner cylinder 12. The outer cylinder 13 is fixed to the mounting seat 14 via a flange portion 13a. A cooling air passage 18 is formed between the inner surface of the outer cylinder 13 and the outer surface of the inner cylinder 12, and the primary cooling air C1 is supplied to the cooling air passage 18 from the primary cooling air supply port 19, and the discharge port It is introduced into the inner cylinder 12 through 12b.

  The secondary cooling unit 4 is provided in the duct 3 downstream of the probe 2 and connected to the inner cylinder 12, and supplies secondary cooling air C <b> 2 from a cooling fan (not shown) to the cooling air pipe 21. A secondary cooling air supply port 22 and the like are provided, and secondary cooling air C2 is supplied from the discharge port 23 to the inside of the duct 3 through the cooling air pipe 21, and the extracted gas G1 discharged from the probe 2 is cooled to a uniform temperature. Provided to do. As shown in FIG. 1C, two discharge ports 23 are provided at positions symmetrical with respect to a straight line Q passing through the center O <b> 2 of the duct 3. The details of the mounting position of the discharge port 23 will be described later.

  The bleed gas G1 after the combustion gas G is cooled by the primary cooling air C1 has a rectified velocity distribution 32, but the duct 3 has a bent portion 3a, and therefore drifts downstream of the bent portion 3a. It has a velocity distribution 33.

  Therefore, as shown in FIG. 2, for example, the two discharge ports 23 are arranged in the same cross section of the duct 3 from the center O2 of the cross section of the duct 3 to the gravity center position Gr side of the velocity distribution 33 of the extraction gas G1. The cooling air C2 is discharged from the discharge port 23 toward the center O2. Here, when the secondary cooling air C2 having the mass M is discharged from each discharge port 23 at the speed V, the momentum vector MV has a magnitude and a direction as illustrated. Therefore, when the two momentum vectors MV are combined, the vector A is obtained. The direction of the vector A is opposite to the direction from the center O2 of the cross section of the duct 3 toward the gravity center position Gr of the velocity distribution 33 of the extracted gas G1. Become. Accordingly, when the discharge ports 23 are arranged at two locations, the discharge ports 23 are moved from the center position O2 of the cross section of the duct 3 in the direction of the center of gravity position Gr of the velocity distribution of the extraction gas G1. The combined vector A of the momentum vector MV of the secondary cooling air C2 discharged from the outlet 23 is set in a direction opposite to the direction from the center O2 of the cross section of the duct 3 toward the gravity center position Gr of the velocity distribution 33 of the extracted gas G1. It corresponds to that.

  Further, according to the simulation of the temperature distribution in the duct 3, the center 23a of the discharge port 23 is crossed over the portion 33a having the highest velocity in the velocity distribution 33 of the extracted gas G1, and the entire flow rate 60 is centered on this portion 33a. It is preferable to position the center of the discharge port 23 within a range R that occupies%. Thereby, the extracted gas G1 discharged from the probe 2 can be secondarily cooled to a uniform temperature by the second cooling air C2.

  In the above-described embodiment, the discharge ports 23 are arranged at two places in a plane perpendicular to the flow of the extraction gas G1, but can be arranged at three or more places. Another arrangement example of the discharge ports 23 will be described with reference to FIG. 3A to 3C show examples in which the discharge ports 23 are arranged at 2 to 5 locations, respectively, and each drawing shows a cross section perpendicular to the flow of the extraction gas G1 in the duct 3. FIG.

  FIG. 3A shows an example in which the discharge ports are arranged at four locations. In this case, the two locations are moved from the center O2 of the cross section of the duct 3 in the direction of the center of gravity Gr of the velocity distribution of the extracted gas G1. Is arranged. Here, since the discharge direction of the secondary cooling air C2 from the discharge port 23 is the center O2 of the cross section of the duct 3, the secondary cooling air C2 having a mass M is discharged from the discharge ports 23 at a speed V. In this case, the momentum vector MV has a magnitude and direction as shown in the figure. Therefore, when the four momentum vectors MV are combined, the vector A is obtained, and the direction of the vector A is opposite to the direction from the center O2 of the cross section of the duct 3 toward the gravity center position Gr of the velocity distribution of the first gas. Become.

  FIG. 3B shows an example in which the discharge ports 23 are arranged at five locations at the same level as the center position O2 of the cross section of the duct 3, and here, secondary cooling air C2 having a mass M from each discharge port 23. Is ejected at a velocity V (a velocity V ′ from the rightmost ejection port 23), the momentum vectors MV and MV ′ have a magnitude and a direction as illustrated. Therefore, when the five momentum vectors MV are combined, the vector A is obtained, and the direction of the vector A is also opposite to the direction from the center O2 of the cross section of the duct 3 toward the gravity center position Gr of the velocity distribution of the first gas. .

  FIG. 3C is an example in which the discharge ports 23 are arranged at two opposite positions, and the secondary cooling air C2 having a mass M from the discharge ports 23a and 22b is respectively at speeds V1 and V2 (V1> V2). The case where it discharged is shown. Also in this case, the direction of the vector A obtained by combining the respective momentum vectors MV1 and MV2 is the center of gravity of the velocity distribution of the first gas from the center O2 of the cross section of the duct 3 in FIG. The direction is opposite to the direction toward the position Gr.

  As described above, in the present invention, the vector A obtained by synthesizing the momentum vector of the secondary cooling air C2 discharged from each discharge port 23 is the center O2 of the cross section of the duct 3 regardless of the number of discharge ports 23 to be arranged. The first gas velocity distribution has a component in a direction opposite to the direction toward the gravity center position Gr. In this case, as in the examples of FIGS. 3B and 3C, the speed or amount of the secondary cooling air C2 discharged from each discharge port 23 does not have to be the same. When operating the bleeder 1, the temperature distribution in the duct 3 after discharging the secondary cooling air C2 is measured, and the amount of cooling air supplied from each outlet 23 is determined according to the measured temperature. It is preferable to control.

  Moreover, in the said embodiment, although the secondary cooling part 4 of the extraction part 1 of the cement kiln chlorine bypass facility demonstrated the case where the extraction gas G1 was cooled with the secondary cooling air C2, more generally, FIG. 1, the combination of the inner cylinder 12 of the probe 2 of the extraction unit 1 and the duct 3 is regarded as one gas pipe, the extraction gas G1 is used as the first gas, and the secondary cooling air C2 is used as the second gas. Then, the extraction unit 1 can be regarded as a gas mixing device that mixes the first gas and the second gas. In the same gas pipe, the drift of dust contained in the first gas, The collision of dust on the inner surface can be minimized, and the first gas and the second gas can be efficiently mixed in the gas pipe.

DESCRIPTION OF SYMBOLS 1 Bleeding part 2 Probe 3 Duct 4 Secondary cooling part 12 Inner cylinder 12a Inlet part 12b Discharge port 12c Center (outlet) 13 Outer cylinder 13a Flange part 14 Mounting seat 15 Rising part 18 Cooling air passage 19 Primary cooling air supply port 21 Cooling Air Pipe 22 Secondary Cooling Air Supply Port 23 Discharge Ports 31-33 Speed Distribution 33a (In Speed Distribution 33) Highest Speed Part C1 Primary Cooling Air C2 Secondary Cooling Air (Second Gas)
G Combustion gas G1 Extraction gas (first gas)
G2 Second gas Gr Center of gravity position

Claims (7)

A gas pipe and a plurality of discharge ports formed in the gas pipe, and a direction perpendicular to the first gas flowing through the gas pipe in the extending direction of the gas pipe and the first gas A gas mixing device that discharges a second gas from each of the plurality of discharge ports in a central direction of the flow to mix the first gas and the second gas,
A direction in which a vector obtained by synthesizing the momentum vector of the second gas discharged from each of the plurality of discharge ports is directed from the center of the cross section of the gas pipe toward the center of gravity of the velocity distribution of the first gas. A gas mixing apparatus having a component in the reverse direction.   The gas mixing apparatus according to claim 1, wherein the plurality of discharge ports are arranged in a plane perpendicular to an extending direction of the gas pipe.   The plurality of discharge ports are disposed at 2 to 4 positions in a plane perpendicular to the extending direction of the gas pipe, and 10% to 50% of the total amount of the second gas from each discharge port. The gas mixing apparatus according to claim 1, wherein gas is discharged.   The plurality of discharge ports are disposed at two positions in a plane perpendicular to the extending direction of the gas pipe, and each of the discharge ports disposed at the two positions is from the center of the cross section of the gas pipe. 4. The gas mixing device according to claim 1, wherein the gas mixing device is arranged at a position moved in the direction of the center of gravity of the velocity distribution of the first gas.   Among the plurality of discharge ports, the center of the discharge port having the largest movement amount in the center of gravity direction of the velocity distribution of the first gas from the center of the cross section of the gas pipe is the first gas in the cross section. 5. It is located in the range which occupies 60% of the whole flow rate centering on the part with the highest speed across the part with the highest speed in the speed distribution of Gas mixing equipment.   The gas mixing apparatus according to claim 1, wherein the plurality of discharge ports are arranged in a plurality of stages with respect to the extending direction of the gas pipe. An operation method of the gas mixing device according to any one of claims 1 to 6,
The total flow rate of the second gas or / and the flow rate of the second gas discharged from each of the plurality of discharge ports are adjusted according to the flow rate of the first gas and / or the center of gravity of the velocity distribution. A method for operating a gas mixing device.

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