JP6784386B2 - Three-fluid nozzle and spraying method using the three-fluid nozzle - Google Patents

Description

The present invention relates to a three-fluid nozzle and a spraying method using the three-fluid nozzle, and more particularly to a three-fluid nozzle that mixes and sprays three fluids supplied from two gas channels and one liquid channel, particularly coal. Suitable as a nozzle that can be used for both exhaust gas cooling and removal of air pollutants (HCl, SOx, NOx, etc.) contained in the exhaust gas in the exhaust gas cooling tower of a burning boiler or garbage incineration facility. Is something that can be done.

Conventionally, an exhaust gas cooling nozzle including a two-fluid nozzle that mixes and injects a coolant (water) and compressed air is installed in an exhaust gas cooling tower of a garbage incineration facility. In addition, a reduction gas injection nozzle consisting of a one-fluid nozzle that injects a reduction gas made of ammonia gas or the like is installed to remove air pollutants such as NOx in the exhaust gas, and two types of nozzles are installed. There may be.

When two types of nozzles including the two-fluid nozzle for cooling the exhaust gas and the one-fluid nozzle for injecting the reducing gas are installed, usually, first, the gas and liquid for cooling are first introduced into the exhaust gas from the two-fluid nozzle. The mixed mist is injected to cool the exhaust gas with water, and then a reducing gas composed of ammonia gas or the like is injected into the exhaust gas from a one-fluid nozzle.
However, if the exhaust gas is not sufficiently cooled by the injection of the cooling mist from the first two-fluid nozzle, the ammonia gas injected from the subsequent one-fluid nozzle for reduction comes into contact with the high-temperature exhaust gas, and the exhaust gas. There is a problem that sulfur cheap is generated by reacting with the SOx inside. Therefore, it is preferable to inject the reducing gas so as not to come into direct contact with the high-temperature exhaust gas.
Further, if two types of nozzles, a two-fluid nozzle for cooling the exhaust gas and a one-fluid nozzle for injecting the reducing gas, are installed, there is a problem that the cost becomes high.

In response to the above problems, the applicant has published Patent No. 4346380 (Patent Document 1) as a spray nozzle installed in an exhaust gas cooling tower of a garbage incineration facility to cool exhaust gas and pollute the air in the exhaust gas. Provided is a three-fluid nozzle that mixes and sprays two types of liquids and one type of gas for the purpose of removing components. Specifically, as shown in FIG. 6, the three-fluid nozzle 100 is composed of a triple pipe composed of an inner pipe 101, an inner pipe 102, and an outer pipe 103, and is inside a central flow path 111 surrounded by the inner pipe 101. An intermediate flow path 112 between the pipe 101 and the middle pipe 102 and an outer peripheral flow path 113 between the middle pipe 102 and the outer pipe 103 are provided, and the central flow path 111, the intermediate flow path 112, and the outer peripheral flow path 113 are provided with The first liquid, the second liquid, and the gas are inserted respectively, and these two kinds of liquids and the compressed air are mixed and sprayed.

In the three-fluid nozzle, water consisting of a neutralizing agent aqueous solution containing caustic soda or the like that neutralizes acidic components (HCl, SOx) contained in the exhaust gas as the first liquid and wastewater that dilutes the first liquid as the second liquid is used. I am using it. Since a scale made of calcium hydrate is generated by mixing the first liquid and the second liquid, external mixing is performed to prevent clogging of the nozzle. Further, it is mixed with a gas composed of compressed air to make water droplets finer and sprayed into the exhaust gas to promote the reaction.

Japanese Patent No. 4346380

As described above, in the three-fluid nozzle of Patent Document 1, since the first liquid is an aqueous solution of the neutralizing agent, it is necessary to adjust the aqueous solution of the neutralizing agent and supply it to the nozzle, and the reducing gas is supplied to the nozzle. There is a problem that it takes more work than when it is supplied to the nozzle in the state.
However, when a reduction gas such as ammonia gas is directly blown into the exhaust gas in order to remove NOx by using a one-fluid nozzle that injects the reduction gas, the reduction gas is released before the reaction as described above. There is a problem that it is thermally decomposed or reacts with SOx to generate sulfur cheap. Further, if the supply pressure of the reducing gas is low, when the reducing gas is injected into the exhaust gas, it is swept away by the flow of the exhaust gas, and there is a problem that the reducing gas does not reach the whole and the reaction efficiency deteriorates. ..

The present invention has been made in view of the above problems, and is a gas-liquid mixing mist in which the first gas and the liquid are mixed in a nozzle for mixing and injecting three fluids of the first gas, the second gas and the liquid. A three-fluid nozzle capable of surrounding the second gas with the gas-liquid mixed mist, contacting the exhaust gas which is the target fluid with the gas-liquid mixed mist, and then contacting the second gas for reaction. The challenge is to provide.
Specifically, for example, a nozzle that injects a gas-liquid mixed mist for cooling a liquid composed of a first gas compressed air and a cooling water into the exhaust gas and a nozzle for injecting a second gas reduction gas into the exhaust gas. A three-fluid that has a function of cooling the exhaust gas and a function of blowing a reducing gas into the nozzle without making direct contact with the exhaust gas so that the nozzle can be reacted efficiently while making one nozzle instead of a separate nozzle. The challenge is to provide a nozzle.
Furthermore, if the supply pressure of the reducing gas of the second gas is low, the reducing gas is swept away by the flow of the exhaust gas and becomes a drift in the cooling tower, and the reducing gas does not reach the whole and the reaction efficiency deteriorates. The challenge is to solve the problem.

In order to solve the above problems, as the first invention, a triple pipe including an inner pipe, a middle pipe, and an outer pipe is provided, and the annular outer peripheral passage between the outer pipe and the middle pipe is a passage for the first gas. The annular intermediate passage between the middle pipe and the inner pipe is a liquid passage, the central passage surrounded by the inner pipe is a second gas passage, and a continuous passage between the outer peripheral passage and the intermediate passage is provided on the injection side. In addition, a gas-liquid mixing passage is provided on the injection side of the communication passage, and a nozzle surrounding the inner pipe is provided at the injection side end of the gas-liquid mixing passage.
Provided is a three-fluid nozzle having a configuration in which a gas-liquid mixing mist that injects the second gas that is ejected from a nozzle at the tip of the inner pipe is mixed internally or externally with a gas-liquid mixing mist that is ejected to the outer periphery.

In the external mixing, the injection-side tip of the inner pipe is projected to the outside from the injection-side tip of the inner pipe and the outer pipe, and the second is placed in the central portion of the gas-liquid mixing mist to be injected from the annular nozzle surrounding the inner pipe. It is preferable that the gas is blown into the gas and mixed externally.

The intermediate passage is provided with a swirling portion, and the liquid is circulated while swirling, and the continuous passage between the outer peripheral passage and the intermediate passage is a swirling passage, and the liquid is swirled while swirling the first gas in the outer peripheral passage. It is preferable that the structure is such that the mixture is collidatively mixed with the gas to make it finer.

The three-fluid nozzle of the first invention is installed in an exhaust gas cooling tower of a coal-fired boiler facility or a garbage incineration facility, and the second gas supplied to the central passage reacts with air pollutants in the exhaust gas. It is preferable that the reducing gas to be reduced, the liquid supplied to the intermediate passage is the cooling water of the exhaust gas, and the first gas supplied to the outer peripheral passage is compressed air.

Further, as a second invention, there is a spraying method in which the three-fluid nozzle of the first invention is used and a gas-liquid mixed mist of the liquid and the first gas is sprayed while surrounding the second gas. providing.
The first gas and the second gas may be different types of gases or the same type of gas.

The three-fluid nozzle is installed in an exhaust gas cooling tower of a garbage incineration facility, etc.
The first gas flowing through the outer peripheral passage is compressed air, the second gas flowing through the central passage is a reducing gas, and the liquid flowing through the intermediate passage is cooling water for gas cooling.
The compressed air and the cooling water are internally mixed to generate a gas-liquid mixed mist for cooling the exhaust gas, and the jet of the reducing gas is projected to the outside through the center of the annular nozzle of the gas-liquid mixed mist. It is preferable that the reducing gas to be injected is surrounded by the gas-liquid mixed mist, and the exhaust gas is cooled by the mixed mist and then brought into contact with the reducing gas.

As described above, using the three-fluid nozzle of the present invention, the reduction gas is placed in the center of the gas-liquid mixing mist for cooling the exhaust gas, which is an internal mixture of a liquid consisting of the compressed air of the first gas and the cooling water. By injecting the second gas and externally mixing it, the high-temperature exhaust gas is cooled by the gas-liquid mixing mist, and the air pollutants in the exhaust gas are removed by the reducing gas of the second gas in the center of the spray pattern. It can be reduced. In addition, the reducing gas of the second gas is blown into the exhaust gas by the momentum of the gas-liquid mixed mist of the first gas and the liquid, so that it is not flown into the exhaust gas and is not flown into the exhaust gas. Since it reaches the center, the supply pressure of the reducing gas of the second gas may be low, and the chemical equivalent ratio can be suppressed.

Instead of the external mixing, the injection port of the central passage is located on the inner side of the annular nozzle of the gas-liquid mixing passage according to the spray target, and the gas is blown around the outer periphery of the second gas injected from the injection port of the central passage. Liquid mixing mist may be sprayed for internal mixing.

When spraying using the three-fluid nozzle of the present invention, the spray pattern becomes narrower and the flow velocity and the momentum of spraying increase as compared with the conventional two-fluid nozzle. This can be suitably used when the wall surface gets wet with a wide-angle spray pattern in a narrow duct, or when the exhaust gas flow is high and the conventional two-fluid nozzle lacks momentum.

According to the three-fluid nozzle of the present invention, a gas-liquid mixed mist of a first gas and a liquid is used to enclose a second gas for injection. As a result, when the three-fluid nozzle of the present invention is attached to the exhaust gas cooling tower, the nozzle that injects the cooling mist into the exhaust gas and the nozzle that injects the reducing gas that removes air pollutants are not separated. After cooling the exhaust gas, the reducing gas can be brought into contact with the cooled exhaust gas while using the number of nozzles. That is, the reducing gas can be blown into the exhaust gas and reacted efficiently without being in direct contact with the high-temperature exhaust gas.
Moreover, since the second gas is injected by the force of the gas-liquid mixed mist of the first gas and the liquid, it reaches from the center to the back of the cooling tower without being flowed by the exhaust gas. Therefore, the supply pressure of the reducing gas of the second gas is sufficient even at a low pressure, and can be suppressed to the chemical equivalent ratio. Further, until the exhaust gas is cooled to a target temperature by the gas-liquid mixed mist, the second gas is covered with the gas-liquid mixed mist, so that it is not thermally decomposed. Further, since the nozzles for cooling the exhaust gas and for injecting the reducing gas can be covered by one nozzle, the equipment cost can be suppressed.

It is sectional drawing of the three fluid nozzles of 1st Embodiment of this invention. It is an enlarged cross-sectional view of the injection side part of FIG. FIG. 2 is a cross-sectional view taken along the line AA of FIG. It is sectional drawing which shows the injection state of three fluids. It is an enlarged sectional view of the injection side part of the three-fluid nozzle of the second embodiment. It is sectional drawing of the conventional three-fluid nozzle.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 4 show the three-fluid nozzle of the first embodiment of the external mixing type.
The three-fluid nozzle 1 of the embodiment is a nozzle installed in an exhaust gas cooling tower of a dust incineration facility, and sprays a cooling mist on the exhaust gas and cools the reducing gas in order to remove air pollutants in the exhaust gas. It is a nozzle that sprays at the same time as mist.

The three-fluid nozzle 1 has a triple tube structure in which an inner tube 2, an inner tube 3, and an outer tube 4 are concentrically stacked. The annular passage between the outer pipe 4 and the inner pipe 3 is an outer peripheral passage 5 through which the first gas A1 flows. The annular passage between the middle pipe 3 and the inner pipe 2 is an intermediate passage 6 through which the liquid Q is circulated. The passage surrounded by the inner pipe 2 is a central passage 7 through which the second gas A2 flows. In the present embodiment, the first gas A1 is compressed air (compressor air), and the second gas A2 is a reducing gas composed of ammonia gas or the like. The liquid Q is a liquid that cools the exhaust gas, and is composed of wastewater generated in a garbage incinerator and / or a melting furnace.

As shown in FIG. 1, the first gas A1 (hereinafter referred to as compressed air A1) is supplied by communicating with the outer peripheral passage 5 and connecting the pipe 50 to the inflow port 5i provided in the outer pipe 4. The cooling liquid Q (hereinafter referred to as cooling water Q) composed of drainage is communicated with the intermediate passage 6 protruding from the supply side closing portion of the outer peripheral passage 5, and the pipe 51 is connected to the inflow port 6i provided in the outer pipe 4. Is being supplied. The second gas A2 made of the reducing gas (hereinafter referred to as the reducing gas A2) is supplied by connecting the pipes 52 with the opening at the supply side end of the central passage 7 as the inflow port 7i.

The outer peripheral passage 5, the intermediate passage 6, and the central passage 7 extend linearly from the supply side (X1) to the injection side (X2). The injection side end closes the outer peripheral passage 5 with the injection side tip wall 4a provided on the outer pipe 4 and is in contact with the injection side annular end 3a of the inner pipe 3. The injection side portion 2a of the inner pipe 2 is projected to the outside with a gap in the center of the hole 4b provided in the center of the injection side tip wall 4a. The gap becomes the injection port 8 of the mixed mist of the compressed air A1 and the cooling water Q, and the injection-side tip opening of the inner pipe 2 protruding to the outside becomes the injection port 9 of the reducing gas A2. That is, the reducing gas A2 sprayed from the nozzle 9 is injected into the center of the cooling mist sprayed from the nozzle 8.

As shown in FIG. 3, a continuous passage including a swirling passage 10 that connects the outer peripheral passage 5 and the intermediate passage 6 is provided in the middle pipe 3 located close to the nozzle 8, and the compressed air A1 flowing through the outer peripheral passage 5 is provided. Is blown into the cooling water Q flowing through the intermediate passage 6 while turning. As shown in FIGS. 2 and 3, the swirling flow path 10 is provided with two sets of swirling flow paths 10A and 10B adjacent to the annular middle pipe 3 in the flow path direction. The swirling flow paths 10A and 10B of each set are eccentric from the outer peripheral surface to the inner peripheral surface of the middle pipe 3 and extend linearly. Four through holes 10A-1 to 10A-4, 10B-1 to 10B It is composed of -4, and the through holes 10A-1 to 10A-4 and 10B-1 to 10B-4 are displaced in the circumferential direction. In this way, the compressed air A1 of the outer peripheral passage 5 is swirled into the intermediate passage 6 through a total of eight through holes drilled from the outer peripheral surface to the inner peripheral surface of the inner pipe 3 to flow into the intermediate passage 6. As a result, the intermediate passage 6 downstream from the swirling passage 10 is designated as the gas-liquid mixing passage 6h.

Further, a throttle portion 6b having a minimum cross-sectional area is provided in the intermediate passage 6 upstream of the swirling flow path 10 of the compressed air A1. Further, a waller portion 2d composed of an arcuate protruding portion is provided on the outer peripheral surface 2c of the inner pipe 2 serving as the inner peripheral wall of the intermediate passage 6 upstream of the throttle portion 6b, and the waller portion 2d is used as the diameter-expanded portion 3e of the middle pipe 3. A swivel portion 6c is provided in the intermediate passage 6 in contact with the inner peripheral surface. The cooling water Q flowing into the intermediate passage 6 is circulated to the injection side while being swirled by the swirling portion 6c.

In this way, the compressed air A1 flows into the cooling water Q flowing while swirling in the intermediate passage 6 from the outer periphery through the through holes 10A-1 to 10A-4 and 10B-1 to 10B-4 on the injection side to collide and mix. , The cooling water Q is refined to generate a gas-liquid mixed mist M. The gas-liquid mixing mist M flows to the injection side while swirling in the gas-liquid mixing passage 6h, and is sprayed from the annular nozzle 8.

The reduction gas A2 is supplied to the central passage 7 inside the inner pipe 2, and the inner pipe 2 gradually reduces the flow path area toward the injection side. The injection side portion 2a of the inner pipe 2 is projected to the outside through the center of the annular nozzle 8 as the minimum cross-sectional area, and the reducing gas A2 injected from the ejection port 9 at the protruding end is injected from the outer annular nozzle 8 gas-liquid. It is made to be blown into the center of the mixed mist M.

In the three-fluid nozzle 1 having the above structure, as shown in FIG. 4, the reducing gas A2 is ejected to the center of the gas-liquid mixing mist M sprayed from the annular nozzle 8 to be in an externally mixed state. In this state, the central reduction gas A2 is injected into the exhaust gas while being surrounded by the gas-liquid mixed mist M on the outer circumference. Therefore, the exhaust gas comes into contact with the gas-liquid mixed mist M and is cooled, and the reducing gas A2 comes into contact with the exhaust gas whose temperature has dropped. Therefore, it is possible to prevent the reduction gas A2 from coming into contact with the high-temperature exhaust gas and thermally decomposing before the reaction, or the SOx and the ammonia gas reacting with each other to generate ammonium sulfate.

The supply pressure of the compressed air A1 and the cooling water Q is P1 having substantially the same pressure, and the supply pressure P2 of the reducing gas A2 is P1> P2. In this way, even if the supply pressure of the reducing gas A2 is reduced, the reducing gas A2 can be blown into the exhaust gas with the momentum of the gas-liquid mixed mist M on the outer circumference. As a result, even if the reduction gas A2 is blown at a low pressure, the reduction gas is not pushed by the flow of the exhaust gas, and the reduction gas is distributed throughout the cooling tower to react the air pollutants in the exhaust gas with the reduction gas. be able to. Therefore, the supply amount of the reducing gas can be suppressed to the chemical equivalent ratio, and the cost can be reduced because the reducing gas is expensive. In addition, if the reducing gas is excessively blown, by-products are generated and the post-treatment is troublesome. However, since the chemical equivalent ratio is used, almost no by-products are generated and the post-treatment can be omitted.
In particular, since the nozzle for cooling the exhaust gas and the nozzle for blowing the reducing gas can be shared by one nozzle, the equipment cost can be significantly reduced.

FIG. 5 shows the three-fluid nozzle 1-B of the second embodiment of the internal mixing type.
In the internal mixing type three-fluid nozzle 1-B, the nozzle 9-B at the tip of the inner pipe 2 on the ejection side is located on the inner side in front of the nozzle 8 of the gas-liquid mixing mist M on the outer circumference. Other configurations are the same as those of the three-fluid nozzle 1 of the first embodiment, and the same part number is added and the description thereof will be omitted. Further, the first gas A1 made of compressed air is supplied to the outer peripheral passage 5, the liquid Q made of exhaust gas cooling water is supplied to the intermediate passage 6, and the second gas A2 made of reducing gas is supplied to the central passage 7 from separate pipes. ing.

Since the injection port 9-B is located in the center of the inside of the injection port 8, the second gas A2 of the reduction gas injected from the injection port 9-B is injected to the outside while being surrounded by the gas-liquid mixed mist M, and is exhaust gas. Blowed in. By internally mixing the gas-liquid mixing mist M for cooling the exhaust gas and the reducing gas in this way, the effect of the reducing gas as a gas for atomizing the cooling water is increased. Therefore, the supply amount of the first gas can be reduced by the amount of the increased atomization performance, and the running cost can be reduced. Moreover, when the aquatic water ratio is used, atomization can be promoted as compared with the case where a conventional two-fluid nozzle is used.

The three-fluid nozzles of the first and second embodiments are attached to an exhaust gas cooling tower of a waste incineration facility and are used for cooling exhaust gas and removing air pollutants, but are used for other purposes such as a coal-fired boiler. It can also be suitably used for. When used for other purposes, the types of the first gas A1, the second gas A2, and the liquid Q of the three fluids injected from the three fluid nozzles are changed. Further, the required pressure of the second gas does not have to be the same as that of the first gas and may be a low pressure, and a second gas that cannot be mixed with the first gas and cannot be used can also be used. For example, in the case of equipment with excess nitrogen gas as a PSA by-product, compressed air (compressor air) is used as the first gas, nitrogen gas is used as the second gas, and the amount of compressed air used is the same as the nitrogen gas. Can be reduced.

Further, the first gas and the second gas may be the same type of gas, for example, compressed air. That is, by using the three-fluid nozzle as the two-fluid nozzle, it is possible to reduce the air-water ratio (reduce the running cost) as compared with the case of using the conventional two-fluid nozzle.
Further, in the three-fluid nozzle, the spray pattern becomes narrower and the flow velocity and the momentum of spraying increase as compared with the conventional two-fluid nozzle. This can be suitably used when the wall surface gets wet with a wide-angle spray pattern in a narrow duct, or when the exhaust gas flow is high and the conventional two-fluid nozzle lacks momentum.

1, 1-B Three-fluid nozzle 2 Inner pipe 3 Middle pipe 4 Outer pipe 5 Outer pipe 5 Outer passage 6 Intermediate passage 6c Swing part 7 Central passage 8, 9 Nozzle 10 (10A, 10B) Swirling flow path 50, 51, 52 Piping A1 No. One gas (compressed air)
A2 Second gas (reduction gas)
Q Liquid (cooling water)

Claims (6)

A triple tube with an inner tube, a middle tube, and an outer tube is provided, and the annular outer peripheral passage between the outer tube and the middle tube is a first gas passage, and the annular path between the middle tube and the inner tube. The intermediate passage is a liquid passage, the central passage surrounded by the inner pipe is a second gas passage, a communication passage between the outer peripheral passage and the intermediate passage is provided on the injection side, and a gas-liquid mixing passage is provided on the injection side from the communication passage. And a nozzle surrounding the inner pipe is provided at the injection side end of the gas-liquid mixing passage.
The continuous passage between the outer peripheral passage and the intermediate passage is a swirling passage.
A three-fluid nozzle having a configuration in which a gas-liquid mixing mist that injects the second gas that is injected from a nozzle at the tip of the inner pipe is internally or externally mixed and sprayed. The injection-side tip of the inner pipe is projected outward from the injection-side tip of the inner pipe and the outer pipe, and the second gas is applied to the central portion of the gas-liquid mixing mist to be injected from the annular nozzle surrounding the inner pipe. The three-fluid nozzle according to claim 1, which is configured to blow in and mix externally. The middle passage comprises a swivel unit, the circulating while swirling the liquid, before Kigaishu the first claim gas colliding mixed with the liquid while swirling and is configured to miniaturization of passages 1 or The three-fluid nozzle according to claim 2. A spraying method in which the second gas is surrounded by a gas-liquid mixed mist of the liquid and the first gas using the three-fluid nozzle according to any one of claims 1 to 3. .. A triple tube with an inner tube, a middle tube, and an outer tube is provided, and the annular outer peripheral passage between the outer tube and the middle tube is a first gas passage, and the annular path between the middle tube and the inner tube The intermediate passage is a liquid passage, the central passage surrounded by the inner pipe is a second gas passage, a communication passage between the outer peripheral passage and the intermediate passage is provided on the injection side, and a gas-liquid mixing passage is provided on the injection side from the communication passage. And an injection port surrounding the inner pipe is provided at the injection side end of the gas-liquid mixing passage, and internal mixing or internal mixing with a gas-liquid mixing mist that injects the second gas injected from the injection port at the tip of the inner pipe to the outer periphery. Using a three-fluid nozzle that is configured to be externally mixed and sprayed
A spraying method in which a gas-liquid mixed mist of the liquid and the first gas is sprayed while surrounding the second gas. The three-fluid nozzle is installed in an exhaust gas cooling tower of a garbage incineration facility, etc.
The first gas flowing through the outer peripheral passage is compressed air, the second gas flowing through the central passage is a reducing gas, and the liquid flowing through the intermediate passage is cooling water for gas cooling.
The compressed air and cooling water are internally mixed to generate a gas-liquid mixed mist for cooling the exhaust gas.
The injection port of the reduction gas was projected to the outside through the center of the annular nozzle of the gas-liquid mixing mist, the reduction gas injected from the injection port was surrounded by the gas-liquid mixing mist, and the exhaust gas was cooled by the mixing mist. mists method according to claim 4 or 5 is contacted with the reducing gas after.

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