CN111629834B

CN111629834B - Spray nozzle and spraying method

Info

Publication number: CN111629834B
Application number: CN201880087443.5A
Authority: CN
Inventors: 大久保雅章; 黑木智之; 藤岛英胜; 平松弘树; 中井志郎; 山本柱; 辻良太
Original assignee: Public University Legal Person Osaka; H Ikeuchi and Co Ltd; Nihon Yamamura Glass Co Ltd
Current assignee: Public University Legal Person Osaka; H Ikeuchi and Co Ltd; Nihon Yamamura Glass Co Ltd
Priority date: 2018-01-26
Filing date: 2018-12-25
Publication date: 2022-09-09
Anticipated expiration: 2038-12-25
Also published as: WO2019146348A1; CN111629834A; JPWO2019146348A1; KR20200110753A; KR102594992B1; JP7182197B2

Abstract

The invention provides a spray nozzle which can inhibit thermal decomposition of an oxidant gas and can efficiently oxidize a gas to be treated with the oxidant gas. The spray nozzle of the present invention is characterized by comprising: the mist atomizing device includes a first ejection hole provided at an end portion of the first pipe, and a second ejection hole provided so as to surround the first pipe, the second ejection hole being provided so that water or an aqueous solution is ejected from the second ejection hole while rotating together with the atomizing gas, and the first ejection hole being provided so that the oxidizing gas ejected from the first ejection hole is supplied to mist containing water or an aqueous solution ejected from the second ejection hole.

Description

Spray nozzle and spraying method

Technical Field

The present invention relates to a spray nozzle and a spraying method.

Background

In the case where the gas to be treated is subjected to the oxidation treatment by the oxidizing gas having a chemical property of thermal decomposition, the treatment is performed after the gas to be treated is cooled to a temperature equal to or lower than the thermal decomposition temperature.

For example, an exhaust gas treatment method is known in which a combustion exhaust gas is treated with an ozone gas having a chemical property of thermally decomposing at a temperature of 150 ℃. In this method, the combustion exhaust gas is purified by supplying ozone gas to the combustion exhaust gas sufficiently cooled in the shower chamber. In this method, a large-scale cooling device is required for cooling the combustion exhaust gas.

Further, an exhaust gas treatment method is known in which a combustion exhaust gas is treated with an ozone gas in a local cooling region by mist (for example, see patent document 2). In this method, since only the local cooling region of the mist is cooled to a temperature equal to or lower than the thermal decomposition temperature of the ozone gas, and the combustion exhaust gas is treated with the ozone gas, a large-scale cooling device is not required.

Documents of the prior art

Patent literature

Patent document 1: japanese laid-open patent publication No. 10-137537

Patent document 2: japanese laid-open patent publication (JP 2015-016434)

Disclosure of Invention

However, when the oxidizing gas is used to oxidize the gas to be treated in the local cooling area using the mist, the oxidizing gas diffuses to the outside of the local cooling area and is thermally decomposed, and therefore it is difficult to efficiently oxidize the gas to be treated.

The present invention has been made in view of the above circumstances, and provides a spray nozzle capable of suppressing thermal decomposition of an oxidizing gas and efficiently oxidizing a target gas with the oxidizing gas.

The present invention provides a spray nozzle, comprising: the second ejection hole is provided so that water or an aqueous solution is ejected from the second ejection hole while rotating together with the atomizing gas, and the first ejection hole is provided so that the oxidizing gas ejected from the first ejection hole is supplied to the mist containing water or the aqueous solution ejected from the second ejection hole.

The spray nozzle of the present invention has a second discharge hole provided so that water or an aqueous solution is discharged while rotating together with a gas for spraying. By spraying water or an aqueous solution and a spraying gas in a two-fluid manner from the second discharge hole, mist having a swirling flow can be formed. In addition, a local cooling region can be formed in the mist by using vaporization heat of water or an aqueous solution.

The spray nozzle of the present invention includes a first discharge hole provided at an end of a first pipe. The first ejection hole is provided so as to supply the oxidizing gas ejected from the first ejection hole into the mist containing water or the aqueous solution ejected from the second ejection hole. By ejecting the oxidizing gas from the first ejection hole, the oxidizing gas can be supplied to the vicinity of the rotating shaft of the mist having the swirling flow.

The swirling flow formed in the mist is an air flow that flows in the ejection direction while rotating around a rotation axis, and has a velocity component in the ejection direction and a velocity component in the rotation direction. Therefore, it is considered that the oxidizing gas supplied from the first discharge hole to the vicinity of the rotation axis flows in the discharge direction in the vicinity of the rotation axis of the swirling flow. The gas to be treated outside the mist is entrained in the gas flow around the outer periphery of the swirling flow, and is considered to be cooled by the heat of vaporization of the mist while flowing along the swirling flow. It is considered that the cooled gas to be treated is oxidized by being brought into contact with the oxidizing gas in the mist.

Therefore, by using the spray nozzle of the present invention, thermal decomposition of the oxidizing gas can be suppressed, and the gas to be treated can be effectively oxidized by the oxidizing gas.

Drawings

Fig. 1 is a schematic sectional view of a spray nozzle according to an embodiment of the present invention.

Fig. 2 is a schematic cross-sectional view of the spray nozzle in a range a surrounded by a broken line in fig. 1.

Fig. 3 is a schematic end view of the spray nozzle as viewed from the direction indicated by the arrow B in fig. 2.

Fig. 4 (a) is a schematic sectional view of the spray nozzle at a broken line C-C of fig. 2, and fig. 4 (b) is a schematic sectional view of the spray nozzle at a broken line D-D of fig. 2.

Fig. 5 (a) is an enlarged end view of a range E surrounded by a broken line in fig. 3, and (b) to (d) are schematic end views of the spray nozzle of the modified example.

Fig. 6 is a schematic partial sectional view of a spray nozzle according to an embodiment of the present invention.

Fig. 7 is a schematic partial sectional view of a spray nozzle according to an embodiment of the present invention.

Fig. 8 is a conceptual diagram of a method for processing a processing target gas by using a spray nozzle according to an embodiment of the present invention.

Fig. 9 is a schematic configuration diagram of an exhaust gas treatment device incorporating a spray nozzle according to an embodiment of the present invention.

Fig. 10 is an explanatory diagram showing measurement positions of the average flow velocity of mist in the first mist test.

Fig. 11 is a graph showing the supply pressure difference of the gas containing ozone when the gas-liquid mixture and the gas containing ozone are ejected from the spray nozzles at different positions at the distal end of the ozone tube.

Fig. 12 is a graph showing the rate of change in the sauter mean particle diameter of droplets contained in a mist formed by ejecting a gas-liquid mixture and an ozone-containing gas from spray nozzles at different positions at the distal end of an ozone tube.

Detailed Description

The spray nozzle of the present invention is characterized by comprising: the first ejection hole is provided at an end portion of the first pipe, and the second ejection hole is provided so as to surround the first pipe, the second ejection hole is provided so that water or an aqueous solution is ejected from the second ejection hole while rotating together with the atomizing gas, and the first ejection hole is provided so that the oxidizing gas ejected from the first ejection hole is supplied to the mist containing water or an aqueous solution ejected from the second ejection hole.

The second ejection hole included in the spray nozzle of the present invention preferably has a circular ring shape. This can increase the velocity component in the rotational direction of the swirling flow of the mist, and can suppress the oxidizing gas discharged from the first discharge hole from diffusing to the outside of the mist and thermally decomposing.

The first tube, the second tube, and the third tube included in the spray nozzle of the present invention preferably have a structure in which the first tube is located inside the second tube and the second tube is located inside the third tube. Preferably, the communication flow path included in the spray nozzle of the present invention is provided to communicate the flow path between the first tube and the second tube and the flow path between the second tube and the third tube, and the internal flow path of the first tube is an oxidizing gas flow path through which the oxidizing gas flows. The flow path between the second tube and the third tube is preferably a gas flow path through which the atomizing gas flows, and the flow path between the first tube and the second tube preferably includes a water flow path through which water or an aqueous solution flows and a gas-liquid mixing section. The gas-liquid mixing section is preferably provided so as to generate a swirling flow while mixing the water or aqueous solution supplied from the water flow path and the atomizing gas blown in from the communication flow path, and the second ejection hole is preferably provided so as to eject a swirling gas-liquid mixture formed by the gas-liquid mixing section from the second ejection hole. With this configuration, the mist can be formed by jetting the water or the aqueous solution from the second jetting hole while rotating together with the atomizing gas, and the oxidizing gas can be supplied to the mist from the first jetting hole.

The spray nozzle of the present invention preferably includes a swirling flow forming portion. Preferably, the swirling flow forming portion is provided in such a manner as to form a swirling flow in the water or aqueous solution flowing in the water flow path, and preferably, the gas-liquid mixing portion is provided in such a manner as to form a swirling flow having the same direction of rotation as that of the swirling flow formed by the swirling flow forming portion. Thus, water or an aqueous solution having a swirling flow can be supplied from the water flow path to the gas-liquid mixing section, and the rotational speed of the swirling flow of the gas-liquid mixture formed by the gas-liquid mixing section can be increased. As a result, the plurality of water droplets jetted from the second jetting hole can be further miniaturized. In addition, the rotation speed of the swirling flow of the mist can be increased.

The first discharge hole included in the spray nozzle of the present invention is preferably arranged on the same plane as the second discharge hole, or preferably arranged to protrude in the discharge direction from the second discharge hole. This makes it possible to supply the oxidizing gas to the vicinity of the rotation axis of the mist, and to suppress thermal decomposition due to diffusion of the oxidizing gas to the outside of the mist.

The spray nozzle of the present invention preferably includes an air discharge hole which is preferably provided so as to surround the second ejection hole or the flow path through which water, an aqueous solution, or a gas for spraying is supplied to the second ejection hole, and which discharges air from the air discharge hole to the outside of the spray nozzle. By discharging the air from the air discharge hole, the air can be supplied to the outer periphery of the swirling flow of the mist and the periphery thereof. Thereby, the air supplied from the air discharge hole is mixed with the gas to be processed around the swirling flow of the mist, and the gas to be processed is cooled. Therefore, thermal decomposition of the oxidant gas in the mist can be suppressed.

The oxidant gas is preferably an ozone-containing gas. Since ozone has a strong oxidizing property, it can oxidize a gas contained in a gas to be treated.

The invention also provides a spraying method, which comprises the following steps: the mist is formed in the gas to be treated by jetting water or an aqueous solution from the second jetting holes while rotating together with the atomizing gas into the gas to be treated flowing through the gas to be treated flow path to which the spray nozzle of the present invention is attached, and the oxidizing gas is jetted from the first jetting holes to supply the oxidizing gas into the mist. The spraying method of the present invention can suppress thermal decomposition of the oxidizing gas and can efficiently oxidize the gas to be treated with the oxidizing gas.

In the spraying method of the present invention, it is preferable that the water or the aqueous solution and the spraying gas are sprayed from the second spray hole at an initial velocity of 30m/s to 340 m/s. The gas to be treated is preferably an exhaust gas containing NOx, and the oxidizing gas is preferably a gas containing ozone.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The structures shown in the drawings and described below are merely examples, and the scope of the present invention is not limited to the structures shown in the drawings and described below.

Fig. 1 to 8 are views related to the spray nozzle of the present embodiment. The description of the drawings is the same as that described above.

The spray nozzle 30 of the present embodiment is characterized by comprising: the first discharge hole 3 is provided at an end portion of the first pipe 4, and the second discharge hole 2 is provided so as to surround the first pipe 4, the second discharge hole 2 is provided so that water or an aqueous solution is discharged from the second discharge hole 2 while rotating together with the atomizing gas, and the first discharge hole 3 is provided so that the oxidizing gas discharged from the first discharge hole 3 is supplied to the mist 24 containing water or an aqueous solution discharged from the second discharge hole 2.

The spraying method of the present embodiment includes the steps of: in the gas to be treated flowing through the gas flow path 21 to which the spray nozzle 30 of the present embodiment is attached, the mist 24 is formed in the gas to be treated by spraying water or an aqueous solution from the second spray holes 2 while rotating together with the spraying gas, and the oxidizing gas is sprayed from the first spray holes 3 to supply the oxidizing gas to the mist 24.

The mist is a substance in which a plurality of water droplets 23 are suspended in a gas. The water droplets 23 contained in the mist may have an average particle diameter of 100 μm or less.

The spray nozzle 30 is not particularly limited as long as it has the second discharge holes 2 and the first discharge holes 3, and may have a structure in which, for example, the first pipe 4 is positioned inside the second pipe 5 and the second pipe 5 is positioned inside the third pipe 6. The spray nozzle 30 may have a triple tube structure including the first tube 4, the second tube 5, and the third tube 6, may have a quadruple tube structure including the first tube 4, the second tube 5, the third tube 6, and the 4 th tube 7, or may have a quintuple tube structure. In addition, the triple pipe structure, the quadruple pipe structure or the quintuple pipe structure may be of a coaxial type. For example, the spray nozzle 30 may have a structure in which the second pipe 5 is coaxially inserted into the third pipe 6, and the first pipe 4 is coaxially inserted into the second pipe 5. In addition, the first tube 4, the second tube 5, the third tube 6, or the 4 th tube 7 may have a cylindrical shape.

The spray nozzle 30 may have a structure in which at least one of an adapter, a mixing sleeve, a core, a nozzle head, and a cap is attached to a front end portion of a triple pipe, a quadruple pipe, or a quintuple pipe.

The spray nozzle 30 has a first ejection hole 3 provided to eject the oxidizing gas. The first spouting holes 3 are provided at the end of the first pipe 4. The first spouting hole 3 may be a center spouting hole. The oxidizing gas is supplied to the first discharge port 3 through the oxidizing gas channel 10, which is an internal channel of the first pipe 4. The oxidant gas flow field 10 includes an inner flow field of the first pipe 4. The oxidizing gas channel 10 may be a channel connecting the internal channel of the first tube 4 and the internal channel of another member. The first tube 4 may be the innermost tube of the multiple tube structure.

The oxidizing gas is not particularly limited as long as it functions as an oxidizing agent, and is, for example, a gas containing ozone. In the case where the oxidant gas is an ozone-containing gas, the oxidant gas flow path 10 may be an ozone gas flow path. The ozone-containing gas can be produced by, for example, an electric discharge method, an electrolytic method, an ultraviolet lamp method, or the like, using air, oxygen, or the like as a raw material. The oxidizing gas may be a thermally decomposable gas.

The spray nozzle 30 has a second discharge hole 2, and the second discharge hole 2 is provided so that fine particles (water droplets 23) of water or an aqueous solution are discharged while rotating together with the atomizing gas. The second spouting hole 2 may be an annular spouting hole. The second spouting hole 2 is provided so as to surround the first spouting hole 3 or the oxidizing gas channel 10. Thereby, the mist 24 can be formed by ejecting water or an aqueous solution and a gas for spraying from the second ejection hole 2, and the oxidizing gas can be supplied into the mist 24 from the first ejection hole 3. The first spouting holes 3 and the second spouting holes 2 can be provided as shown in fig. 3, for example.

For example, water or an aqueous solution supplied from the water channel 11 and the atomizing gas supplied from the gas channel 12 may be internally mixed and ejected from the second ejection hole 2. The second ejection hole 2 may be an annular hole having an inner wall formed by the first pipe 4 and an outer wall formed by the second pipe 5 or the third pipe 6.

The spray nozzle 30 may have a support portion 18, and one end of the support portion 18 is fixed to the first pipe 4 and the other end is fixed to a pipe (the second pipe 5 or the third pipe 6) outside the first pipe 4. The support 18 may be provided in such a manner that the first tube 4 is fixed at the center of the tube outside thereof. This can prevent the first tube 4 from being damaged by vibration during spraying. In addition, the spray nozzle 30 may have a plurality of supports 18.

The support portion 18 may be provided on the second spouting hole 2. For example, as shown in fig. 5 (b) to (d), a plurality of support portions 18 may be provided in the second ejection port 2. In this case, the second discharge hole 2 may have a shape in which an annular discharge hole is cut by the support portion 18. Fig. 5 (b) to (d) are end views corresponding to fig. 5 (a), and fig. 5 (a) is an end view of a range E surrounded by the broken line of fig. 3.

The initial velocity of the water or aqueous solution and the atomizing gas ejected from the second ejection hole 2 may be, for example, 30m/s to 340 m/s. This can increase the velocity component in the ejection direction and the velocity component in the rotation direction of the swirling flow of the mist 24, and can suppress thermal decomposition due to diffusion of the oxidizing gas ejected from the first ejection holes 3 to the outside of the mist 24.

The water flow path 11 may be provided in a flow path having a circular tubular flow path cross section between the first tube 4 and the second tube 5, for example. The water or aqueous solution flowing through the water flow path 11 may be cooling water or an alkaline aqueous solution, for example. The water or aqueous solution supplied from the water channel 11 is ejected from the second ejection hole 2 to form a plurality of water droplets 23 constituting mist 24.

The gas flow path 12 may be provided in a flow path having a circular tubular flow path cross section between the second tube 5 and the third tube 6, for example. The atomizing gas flowing through the gas flow path 12 is a gas for atomizing the water or the aqueous solution supplied from the water flow path 11. As the gas for spraying, for example, air, nitrogen, oxygen, or the like can be used.

The spray nozzle 30 may have a communication flow path 13, and the communication flow path 13 may be provided so as to communicate a flow path between the first pipe 4 and the second pipe 5 with a flow path between the second pipe 5 and the third pipe 6. The gas flow path 12 and the communication flow path 13 may be provided so that the atomizing gas flowing through the gas flow path 12 flows into the communication flow path 13 and flows into the flow path between the first tube 4 and the second tube 5. The portion of the atomizing gas flowing into the flow path between the first pipe 4 and the second pipe 5 becomes the gas-liquid mixing portion 16. The gas-liquid mixing portion 16 may be provided so as to blow the atomizing gas from the communication passage 13 into a passage having an annular passage cross section.

In the gas-liquid mixing portion 16, the water or the aqueous solution supplied from the water flow path 11 is mixed by collision with the atomizing gas blown from the communication flow path 13, and the water or the aqueous solution is pulverized and atomized by the high-speed flow of the atomizing gas. The gas-liquid mixture including the fine particles (water droplets 23) of the water or aqueous solution formed in this way and the ejection gas flows through the gas-liquid mixture passage 15 and is ejected from the second ejection port 2.

The communication passage 13 may be provided so that the atomizing gas is blown into the circumferential direction of the passage between the first pipe 4 and the second pipe 5. Thereby, the velocity component of the atomizing gas flowing through the communication channel 13 can be converted into a velocity component in the circumferential direction (rotational direction), and a swirling flow can be generated in the gas-liquid mixing portion 16. Further, the swirling flow can be accelerated, and fine particles of water or an aqueous solution can be formed. Further, the mist 24 formed by ejecting the gas-liquid mixture from the second ejection hole 2 may be caused to generate a swirling flow. The spray nozzle 30 may include a plurality of communication channels 13. This makes it possible to further increase the speed of the swirling flow in the gas-liquid mixing section 16, and to further reduce the size of fine particles (water droplets) of water or an aqueous solution. In addition, the rotational speed of the swirling flow of the mist 24 can be increased. The plurality of communication channels 13 may be provided so that the atomizing gas is blown in the same circumferential direction.

The plurality of communication channels 13 may be provided as shown in fig. 2 and 4, for example. In the cross section of the broken line C-C in fig. 2 shown in fig. 4 (a), the 4 communication passages 13a to 13d are provided so that the atomizing gas is blown into the gas-liquid mixing portion 16 in the same circumferential direction. In the cross section of the broken line D-D in fig. 2 shown in fig. 4 (b), the 4 communication passages 13e to 13h are provided so that the atomizing gas is blown into the gas-liquid mixing section 16 in the same circumferential direction. The communication passages 13a to 13d and the communication passages 13e to 13h are provided so that the injection ports do not overlap and are provided so that the atomizing gas is injected in the same circumferential direction. By providing the plurality of communication flow paths 13 in this way, the rotational speed of the swirling flow formed in the gas-liquid mixing section 16 can be increased, and the fine particles of water or the aqueous solution can be further reduced in size. In addition, the rotation speed of the swirling flow of the mist 24 can be increased.

The first ejection hole 3 is provided to supply the oxidizing gas into the mist 24 containing fine particles (water droplets 23) of the water or the aqueous solution ejected while rotating from the second ejection hole 2. Thereby, the oxidizing gas supplied from the first ejection hole 3 to the vicinity of the rotation axis of the swirling flow of the mist 24 can be made to flow in the ejection direction in the vicinity of the rotation axis of the swirling flow of the mist 24, and can react with the gas to be processed in the local cooling region of the mist 24.

The spray nozzle 30 can be used, for example, in the following manner: the water or the aqueous solution and the atomizing gas are ejected into the gas to be treated while being rotated from the second ejection hole 2 to form mist 24, and the oxidizing gas is supplied into the mist 24 from the first ejection hole 3. For example, spraying may be performed as shown in fig. 8.

The swirling flow formed in the mist 24 is an air flow that flows in the ejection direction while rotating around a rotation axis, and has a velocity component in the ejection direction and a velocity component in the rotation direction. Therefore, it is considered that the oxidizing gas supplied from the first ejection hole 3 to the vicinity of the rotation axis flows in the ejection direction in the vicinity of the rotation axis of the swirling flow. The gas to be treated outside the mist 24 is entrained in the gas flow around the outer periphery of the swirling flow, and is cooled by the heat of vaporization of the mist 24 while flowing along the swirling flow. The cooled gas to be treated is oxidized by being brought into contact with the oxidizing gas in the mist 24. Therefore, thermal decomposition of the oxidizing gas can be suppressed, and the oxidizing gas can be used to efficiently perform the oxidation treatment on the gas to be treated.

The exhaust gas to be treated is not particularly limited as long as it is a gas oxidized by the oxidant gas, and may be, for example, a combustion exhaust gas containing NOx. In this case, the oxidant gas may be an ozone-containing gas. The exhaust gas to be treated may contain NOx and SOx.

Ozone gas has strong oxidizing properties and acts as an oxidizing agent. Therefore, by mixing the combustion exhaust gas containing NOx with the ozone gas, the NO gas which is contained in the combustion exhaust gas and is hardly soluble in water can be oxidized to NO which is easily reacted with water and the reducing agent ₂ A gas. In addition, NO in the combustion exhaust gas ₂ The gas may be removed by a reducing agent or the like. In this way, the oxidation treatment of the NO gas with the ozone gas can be used for the removal treatment of NOx in the combustion exhaust gas.

However, ozone gas has thermal decomposition properties, and when it exceeds 150 ℃, the thermal decomposition rate increases. Therefore, the oxidation treatment of the combustion exhaust gas with ozone gas needs to be performed at a temperature of 150 ℃ or lower.

When the mist 24 is formed in the combustion exhaust gas by the spray nozzle 30 of the present invention and the ozone-containing gas (oxidant gas) is supplied to the mist 24, the ozone gas and the combustion exhaust gas can be efficiently mixed in the local cooling region in the mist 24, and therefore, the utilization efficiency of the ozone gas can be improved.

The first discharge port 3 may be disposed on the same surface (on the discharge port surface) as the second discharge port 2, as in the spray nozzle 30 shown in fig. 1 to 4. This allows the gas-liquid mixture ejected from the second ejection holes 2 and the oxidizing gas ejected from the first ejection holes 3 to be appropriately mixed externally, thereby expanding the reaction area between the target gas and the oxidizing gas.

The first discharge port 3 may be disposed to protrude in the discharge direction from the second discharge port 2 (the discharge port surface) as in the spray nozzle 30 shown in fig. 6. This makes it possible to supply the oxidizing gas to the vicinity of the rotation axis of the mist 24, and to suppress the oxidizing gas from diffusing to the outside of the mist 24 and thermally decomposing.

The first discharge hole 3 may be arranged on the inner side of a discharge hole (discharge opening surface) through which the plurality of water droplets 23 and the atomizing gas are discharged to the outside of the atomizing nozzle 30, as in the atomizing nozzle 30 shown in fig. 7. As in the spray nozzle 30 shown in fig. 7, the outer wall of the second discharge hole 2 may be provided so as to protrude in the discharge direction from the first discharge hole 3. This can prevent the water droplets discharged from the second discharge holes 2 to the outside of the nozzle from becoming coarse, and can form fine mist 24. Therefore, the cooling efficiency of the mist 24 can be improved.

Even when the first discharge holes 3 (the tips of the first pipes 4) are arranged inside the nozzle with respect to the discharge surface, the first discharge holes 3 may be arranged such that the oxidizing gas discharged from the first discharge holes 3 is supplied to the mist 24 outside the spray nozzle 30 (external mixing). This makes it possible to supply the oxidizing gas to the vicinity of the rotation axis of the mist 24 having the swirling flow, and to suppress thermal decomposition of the oxidizing gas.

For example, as in the spray nozzle 30 shown in fig. 7, the tip (first discharge hole 3) of the first tube 4 may be slightly recessed from the nozzle opening surface. For example, the distance (the depth of the concave portion) between the tip 19 (the nozzle surface) of the outer wall of the second discharge port 2 and the first discharge port 3 (the tip of the first pipe 4) may be 0.01mm to 2 mm. The depth of the recess may be 0.01mm to 1 mm.

The spray nozzle 30 may include a swirling flow forming portion 17, and the swirling flow forming portion 17 may be provided to form a swirling flow in the water or aqueous solution flowing through the water flow path 11. The swirling flow forming portion 17 may be provided in such a manner as to generate a swirling flow in the same rotational direction as that of the swirling flow formed by the gas-liquid mixing portion 16. Thus, water or an aqueous solution having a swirling flow can be supplied from the water flow path 11 to the gas-liquid mixing section 16, and the rotational speed of the swirling flow of the gas-liquid mixture formed by the gas-liquid mixing section 16 can be increased. As a result, the fine particles (water droplets) of water or the aqueous solution can be further reduced in size. In addition, the rotation speed of the swirling flow of the mist 24 can be increased.

The swirling flow forming portion 17 may have, for example, a screw-shaped blade. By causing water or an aqueous solution to flow along the blade, a swirling flow can be formed in the water or the aqueous solution flowing in the water flow path 11. The vanes may be provided on the outer peripheral surface of the first pipe 4, for example.

The nozzle 30 may include an air discharge hole 8, and the air discharge hole 8 is provided in such a manner as to discharge air to the outside of the nozzle 30. The air discharge hole 8 may be provided so as to surround the second discharge hole 2 or a flow path for supplying water, an aqueous solution, or a spray gas to the second discharge hole 2. By discharging air from the air discharge hole 8, air can be supplied to the outer periphery of the swirling flow of the mist 24 and the periphery thereof. Thereby, the gas to be treated is mixed with the supplied air around the swirling flow of the mist 24, and the gas to be treated is cooled. Therefore, the gas to be treated can be cooled before being mixed with the mist 24, and thermal decomposition of the oxidant gas in the mist 24 can be suppressed. Further, by discharging air from air discharge hole 8, dust can be prevented from adhering to the tip of spray nozzle 30. In addition, the temperature of the tip portion of the spray nozzle 30 can be suppressed from increasing.

The air outlet hole 8 may be a single outlet hole or may be formed of a plurality of outlet holes. The air outlet hole 8 may be an annular outlet hole. For example, the air outlet holes 8 may be provided as shown in FIGS. 1 to 3. In this case, an air flow path 14 may be provided between the third duct 6 and the 4 th duct 7. The air supplied from the air flow path 14 can be discharged from the air discharge hole 8.

The spray nozzle 30 may be provided, for example, so as to flow air in the atmosphere through the air flow passage 14 and discharge the air from the air discharge hole 8 to the flow passage 21 by utilizing a difference between the atmospheric pressure and the atmospheric pressure inside the flow passage 21 through which the gas to be treated flows.

Fig. 9 is a schematic configuration diagram of an exhaust gas treatment device 80 incorporating the spray nozzle 30 of the present embodiment. In the exhaust gas treatment device 80, the exhaust gas containing NOx discharged from the glass melting furnace 41 is subjected to exhaust gas treatment in the exhaust gas flow path 45. The exhaust gas flow path 45 is a flow path through which the exhaust gas discharged to the atmosphere flows from the exhaust gas source. The exhaust gas flow path 45 may be provided with a reaction tower 42 and an electric dust collector 43. The exhaust gas treatment device 80 may be a device for treating exhaust gas from a boiler, an exhaust gas from a waste incinerator, or the like.

The spray nozzle 30 is provided to form the first mist 24 in the exhaust gas by spraying fine particles of the cooling water 71 from the second spray holes 2 into the exhaust gas flowing through the exhaust gas flow path 45 while rotating together with the air (atomizing gas). The spray nozzle 30 is provided to discharge the gas containing ozone from the first discharge hole 3 and supply the gas containing ozone into the first mist 24. The swirling flow of the first mist 24 can suppress the ozone gas from diffusing to the outside of the first mist 24, and the NO gas contained in the exhaust gas can be efficiently reacted with the ozone gas in the local cooling region of 150 ℃. As a result, the NO gas in the exhaust gas can be efficiently converted into NO ₂ A gas. The temperature of the exhaust gas upstream of the first mist 24 is 150 ℃. The temperature of the exhaust gas upstream of the first mist 24 may be 200 ℃.

The plurality of spray nozzles 30 may be arranged in such a manner as to surround the exhaust gas passage 45 and such that each spray nozzle 30 sprays the cooling water 71, the ozone-containing gas, or the like toward the central portion of the exhaust gas passage 45. Further, the plurality of spray nozzles 30 may be provided so that the cooling water 71, the ozone-containing gas, and the like are discharged from each of the plurality of spray nozzles 30 to form 1 of the first mist 24. This makes it possible to pass most of the exhaust gas flowing through the exhaust gas flow path 45 through the first mist 24, and thus efficiently convert the NO gas in the exhaust gas into NO ₂ A gas.

The exhaust gas treatment device 80 may be provided with a spray nozzle 67, and the spray nozzle 67 may be provided on the downstream side of the first mist 24 of the exhaust gas flow path 45The exhaust gas is sprayed with an aqueous solution 72 containing at least NaOH dissolved therein to form a second mist 47. The exhaust gas flowing through the exhaust gas flow path 45 may contain SOx. The spray nozzle 67 is used to spray SOx and NO toward the downstream side of the first mist 24 ₂ The second mist 47 can be formed by spraying the aqueous NaOH solution 72 into the exhaust gas. The spray nozzle 67 is, for example, a two-fluid nozzle.

Since the exhaust gas flowing in the exhaust gas flow path 45 contains SO ₂ The fine water droplets contained in the second mist 47 contain NaOH, and a chemical reaction represented by the following formula (1) can be performed in the second mist 47. Therefore, SO contained in the exhaust gas can be removed ₂ (desulfurization of the exhaust gas is possible), and Na as a reducing agent can be generated in the minute liquid droplets of the second mist 47 ₂ SO ₃ 。

SO ₂ +2NaOH→Na ₂ SO ₃ +H ₂ O···(1)

In addition, the exhaust gas flowing through the exhaust gas flow path 45 contains NO generated by oxidation of NO by ozone ₂ The gas-liquid reaction shown in the following formula (2) can be carried out.

2NO ₂ +4Na ₂ SO ₃ →N ₂ +4Na ₂ SO ₄ ···(2)

Therefore, NO can be mixed in the second mist 47 ₂ Reduction to N ₂ NOx in the exhaust gas can be removed. Since the chemical reactions of the formulae (1) and (2) are considered to proceed in the fine water droplets of the second mist 47 or in the gas-liquid interface between the fine water droplets and the exhaust gas, the time during which the fine water droplets are present can be set to a time (which takes about 1 second) or longer necessary for these chemical reactions to proceed.

With the progress of the chemical reaction of formula (2), with the presence of a reducing agent Na ₂ SO ₃ Generation of Na ₂ SO ₄ And Na is produced in the exhaust gas ₂ SO ₄ And (3) dust.

Spray nozzle 67 may also have NaOH and a reducing agent (e.g., Na) dissolved therein ₂ SO ₃ ) The mixed aqueous solution of (2) is sprayed into the exhaust gas. In this case, NO in the exhaust gas can be reduced by the reducing agent ₂ Reduction to N ₂ Therefore, the exhaust gas containing no SOx or the exhaust gas having a sufficiently low SOx concentration can also flow in the exhaust gas flow path 45. In addition, only Na generated by SOx in the exhaust gas passes through ₂ SO ₃ NO can be converted to ₂ Fully reduced to N ₂ In the case of (3), a spray nozzle 67 may be provided to spray a mixed aqueous solution in which NaOH and a reducing agent are dissolved.

The spray nozzle 67 may spray the NaOH aqueous solution 72 into the exhaust gas from which the first mist 24 disappears to form the second mist 47. Thereby, the first mist 24 and the second mist 47 can be separated and formed, and the reducing agent in the second mist 47 can be suppressed from reacting with the ozone gas in the first mist 24.

As in the exhaust gas treatment device 80 shown in fig. 9, in the case where the spray nozzle 30 is provided to form the first mist 24 inside the reaction tower 42 and the spray nozzle 67 is provided to form the second mist 47 inside the reaction tower 42, the exhaust gas treatment device 80 may include a spray nozzle 68 provided to spray cooling water (seal water 64) into the exhaust gas flowing through the reaction tower 42 to form the third mist 48. By providing the spray nozzles 68, the exhaust gas can be cooled by the first to third mists, and even if the exhaust gas is a high temperature exhaust gas (for example, the temperature of the inlet of the reaction tower 42 is 450 ℃ or higher), the temperature of the exhaust gas flowing into the dust collector 43 can be 350 ℃ or lower or 230 ℃ or lower.

The exhaust gas treatment device 80 may include a dust collector 43 on the downstream side of the first mist 24 and the second mist 47 in the exhaust gas flow path 45. By providing the dust collector 43, Na generated in the exhaust gas flow path 45 can be removed from the exhaust gas ₂ SO ₄ And (3) dust. The dust collector 43 may be an electric dust collector or a bag filter.

Experiment of waste gas treatment

The exhaust gas discharged from the glass melting furnace was treated by an exhaust gas treatment apparatus shown in FIG. 9. In addition, the spray nozzle 30 is a spray nozzle as shown in FIGS. 1 to 4. The diameter of the tube of the reaction column was 3.5 m. The amount of exhaust gases is about 13000Nm ³ The flow rate of the off-gas at an off-gas temperature of about 360 ℃ in the reaction column was about 0.8 m/sec. Further, the concentration of NOx at the inlet of the reaction column (in terms of oxygen concentration: 15%)Concentration) of about 220ppm, SOx concentration (concentration when converted to oxygen concentration of 15%) of about 180ppm, and oxygen concentration of about 8%.

7 spray nozzles 30 are provided at equal intervals on the inner periphery of the reaction tower, and a gas-liquid mixture in which cooling water and air are mixed is sprayed from the second spray holes to the exhaust gas flowing through the reaction tower in each spray nozzle 30, and the first mist is formed. The first mist ejected from each of the spray nozzles 30 has a swirling flow. Further, the ozone-containing gas generated by the ozone generator is supplied into the first mist from the first discharge hole of each spray nozzle 30. Further, air in the atmosphere is caused to flow into the reaction tower from the air discharge holes of the respective spray nozzles 30. In addition, the exhaust gas treatment experiment was performed by ejecting the first mist and the ozone-containing gas from the spray nozzle 30 under each of the spray conditions 1 to 3 shown in table 1.

[ Table 1]

	Condition 1	Condition 2	Condition 3
				Total amount of cooling water	0.46m ³ /h	0.78m ³ /h	0.80m ³ /h
Number of nozzles	7 root of Chinese goldthread	7 root of Chinese goldthread	7 root of Chinese angelica
				Amount of water per nozzle	66L/h	112L/h	114L/h
Hydraulic pressure	0.12MPa	0.14MPa	0.14MPa
				Air pressure (for spraying)	0.16MPa	0.17MPa	0.20MPa
Amount of ozone injected	About 36mol/h	About 36mol/h	About 36mol/h

A 2% NaOH aqueous solution (containing no reducing agent) was sprayed into the exhaust gas flowing through the reaction tower by 7 spray nozzles 67 provided at equal intervals on the inner periphery of the reaction tower on the downstream side of the spray nozzles 30 to form a second mist. The total spray amount of the spray nozzle 67 was 0.35m under the spray conditions 1 to 3, respectively ³ /h、0.47m ³ /h、0.45m ³ /h。

In addition, the spraying of the spray nozzle 68 is not performed. In addition, the dust collector uses an electric dust collector.

The results of measuring the temperature of the local cooling zone of the first mist and the oxidation efficiency of ozone gas to NO (Delta NO/O) in the exhaust gas treatment experiments respectively carried out under the spraying conditions 1 to 3 were measured ₃ ) Shown in table 2. In addition, waste at the inlet of the reaction columnThe temperature of the gas was about 360 ℃ and the temperature of the off-gas at the outlet of the reaction column was about 210 ℃.

[ Table 2]

	Condition 1	Condition 2	Condition 3
				Measuring temperature of thermometer	About 95 deg.C	About 70 deg.C	About 70 deg.C
ΔNO/O ₃	39.2％	44.3％	83.2％

Oxidation efficiency of NO by ozone gas (Delta NO/O) ₃ ) Is the molar ratio of the amount of NO gas oxidized Δ NO in the reaction tower to the amount of ozone gas injected into the first mist from the first ejection hole. Delta NO/O ₃ The larger the value of (b), the more the amount of NO gas oxidized by ozone. Further, it is considered that if Δ NO/O ₃ If the value of (b) is small, the amount of ozone that is not used for oxidation of NO and is thermally decomposed is large among the injected ozone.

The temperature of the local cooling region of the first mist is 100 ℃ or lower under any of conditions 1 to 3, and it is considered that thermal decomposition of ozone in the local cooling region is suppressed. In condition 1, the amount of cooling water is smaller than in

conditions

2 and 3, and therefore the temperature of the local cooling region is considered to be higher than in

conditions

2 and 3.

ΔNO/O ₃ The value of (b) is 50% or less under the

conditions

1 and 2, while 80% or more under the condition 3. The spray amount of the cooling water under the

conditions

2 and 3 was substantially the same, and the supply pressure of the spraying gas (air) under the condition 3 was higher than that under the condition 2. Therefore, it is found that the efficiency of oxidizing NO with ozone gas can be improved by increasing the air supply pressure.

First spray experiment

Using the spray nozzle shown in fig. 1 to 4, a gas-liquid mixture in which cooling water and air were mixed was ejected from the second ejection holes to form a first mist, and the average flow velocity of a plurality of water droplets and the particle diameter of the water droplets in the first mist were measured. The spray conditions in this measurement were the same as the water pressure and air pressure in conditions 1 to 3 shown in table 1, and the average flow velocity in the X direction of a plurality of water droplets at points a and B shown in fig. 10 was measured to measure the particle diameter of the water droplet at point B. The measurement results are shown in Table 3.

[ Table 3]

	Condition 1	Condition 2	Condition 3
				Average flow velocity at point A	25.3m/s	28.9m/s	31.8m/s
At point BAverage flow velocity of	12.0m/s	14.5m/s	16.1m/s
				Maximum particle diameter of water droplet	115μm	185μm	180μm
Average particle diameter of water droplets	43.9μm	64.6μm	56.8μm

With respect to the average flow rates at points a and B, condition 2 is faster than condition 1, and condition 3 is faster than condition 2. This is because the higher the air pressure and the water pressure are, the faster the average flow velocity of the plurality of water droplets is. Further, it is considered that the higher the air pressure and the water pressure is, the faster the rotational speed of the swirling flow of the first mist is. Further, since the average particle diameter of the water droplets in the mist is 70 μm or less, the water droplets jetted from the second jetting hole float with the flow of the gas.

In the exhaust gas treatment experiment,. DELTA.NO/O under condition 3 ₃ The reason why (a) is higher is not clear, but it is considered that the rotational speed of the swirling flow of the first mist is fastest in condition 3, and therefore, the swirling flow of the first mist can be utilized to suppress the ozone gas from diffusing to the outside of the first mist, and the thermal decomposition of the ozone gas can be suppressed.

Second spray experiment

A spray nozzle in which the tip (first discharge hole 3) of the first tube 4 (ozone tube) is positioned on the discharge surface (the distance d from the discharge surface to the tip of the ozone tube is 0mm) as in the spray nozzle shown in fig. 2, a spray nozzle in which the tip (first discharge hole 3) of the first tube 4 (ozone tube) protrudes from the discharge surface (d is 2mm) as in the spray nozzle shown in fig. 6, and five spray nozzles in which the tip (first discharge hole 3) of the first tube 4 (ozone tube) is disposed at a position recessed from the discharge surface as in the spray nozzle shown in fig. 7 (d is-1 mm, -2mm, -3mm, -4mm, -5mm) were manufactured.

Using the produced spray nozzle, a gas-liquid mixture in which cooling water and air are mixed is ejected from the second ejection hole to form a first mist, and ozone-containing gas is ejected from the first ejection hole. The sauter mean particle diameter D of the water droplets at point B (point 1000mm from the tip of the spray nozzle 30) in fig. 10 of the formed first mist was measured. The supply pressure was adjusted so that the supply flow rate Qw of the cooling water was 150L/h, the supply flow rate Qa of the air was 500L/min, and the supply flow rate Qo of the ozone-containing gas was 100L/min. The measurement results are shown in table 4, fig. 11, and fig. 12.

[ Table 4]

The supply pressure difference Δ Po of the ozone-containing gas shown in table 4 and fig. 11 represents the difference from the reference pressure when the ozone supply pressure Po is set as the reference pressure in the measurement using the spray nozzle having d of 0 mm.

The sauter mean particle diameter D shown in table 4 is expressed in percentage based on the sauter mean particle diameter D measured in a measurement using a spray nozzle with D being 0mm (100%). The change rate of the sauter mean particle size shown in table 4 and fig. 12 is a change rate of the mean particle size D from the reference mean particle size.

As shown in table 4 and fig. 11, it is understood that the supply pressure Po of the ozone-containing gas in the measurement using the spray nozzles with d of-1 mm and 2mm is substantially the same as the supply pressure Po (reference pressure) of the ozone-containing gas in the measurement using the spray nozzles with d of 0mm, but the supply pressure difference Δ Po increases as the distance from the nozzle orifice surface to the tip of the ozone tube increases (the tip of the ozone tube is located deeper) in the measurement using the spray nozzles with d of-2 mm, -3mm, -4mm, and-5 mm. When the distal end of the ozone tube is located at a deep position, the first discharge hole 3 is affected by the discharge pressure of the gas-liquid mixture discharged from the second discharge hole 2, and therefore the supply pressure Po of the ozone-containing gas increases.

Although the tip of the ozone tube is disposed at a position recessed from the nozzle opening surface in the spray nozzle having d-1 mm, the supply pressure Po of the ozone-containing gas is substantially the same as the supply pressure Po (reference pressure) of the ozone-containing gas in the measurement using the spray nozzle having d-0 mm. Therefore, in this spray nozzle, it is considered that the gas containing ozone ejected from the first ejection holes 3 is not mixed with the gas-liquid mixture ejected from the second ejection holes 2 in the interior of the spray nozzle (internal mixing), but is mixed with the gas-liquid mixture outside the spray nozzle (external mixing).

As shown in table 4 and fig. 12, the sauter mean particle diameter D of the water droplets measured in the measurement using the spray nozzles D ═ 1mm, -2mm, -3mm, -4mm and-5 mm was small, but the sauter mean particle diameter D of the water droplets increased in the measurement using the spray nozzle D ═ 0mm, and the sauter mean particle diameter D of the water droplets further increased in the measurement using the spray nozzle D ═ 2 mm. Therefore, it is known that the position of the distal end of the ozone tube affects the average particle diameter D of water droplets contained in mist.

Therefore, it is found that by setting D to-2 mm. ltoreq.d < 0mm, the average particle diameter D of the water droplets contained in the mist can be reduced while suppressing the increase in the supply pressure of the ozone-containing gas. In addition, in the case where the air flow rate Qa is the same, the smaller the average particle diameter D of the water droplets of the mist, the higher the cooling efficiency.

Description of the reference numerals

2: second ejection hole 3: first ejection hole 4: first pipe 5: second pipe 6: third pipe 7: fourth tube 8: air discharge hole 10: oxidant gas channel 11: water flow path 12: gas flow paths 13, 13a to 13 h: communication flow path 14: air flow path 15: gas-liquid mixture flow path 6: gas-liquid mixing section 17: rotating flow forming portion 18: support portion 19: front end 21 of outer wall of second ejection hole: process gas flow path 22: flow path wall 23: water droplet 24: first mist 30: first spray nozzle 41: glass melting furnace 42: reaction column 43: the dust collector 44: chimney 45: exhaust gas flow path 47: second mist 48: third mist 49: water seal grooves 52, 52a, 52b, 52 c: pumps 55, 55a, 55b, 55c, 55 d: thermometers 56, 56a, 56b, 56 c: gas concentration measuring device 58: ORP meter 62: dust 64: seal water (cooling water) 66: ozone generating device 67: second spray nozzle 68: third spray nozzle 69: the air compressor 71: cooling water 72: aqueous NaOH solution (or NaOH and Na) ₂ SO ₃ Mixed aqueous solution of (1) 80: an exhaust gas treatment device.

Claims

1. A spray nozzle comprising a first discharge hole provided at an end of a first pipe, a second discharge hole provided so as to surround the first pipe, a second pipe, a third pipe, and a communication flow path,

the first tube, the second tube, and the third tube have a structure in which the first tube is located inside the second tube and the second tube is located inside the third tube,

the communication flow path is provided so as to communicate a flow path between the first tube and the second tube with a flow path between the second tube and the third tube,

the inner flow path of the first tube is an oxidant gas flow path through which oxidant gas flows,

the flow path between the second pipe and the third pipe is a gas flow path through which the atomizing gas flows,

the flow path between the first pipe and the second pipe includes a water flow path through which water or an aqueous solution flows and a gas-liquid mixing portion,

the gas-liquid mixing section is provided so as to generate a swirling flow while mixing water or an aqueous solution supplied from the water flow path with the atomizing gas blown in from the communication flow path,

the second discharge hole is provided so that the rotating gas-liquid mixture formed by the gas-liquid mixing section is discharged from the second discharge hole while rotating,

the first ejection hole is provided so as to supply the oxidizing gas ejected from the first ejection hole into the mist containing water or the aqueous solution ejected from the second ejection hole.

2. The spray nozzle according to claim 1, wherein the second ejection hole has a circular ring shape.

3. The spray nozzle according to claim 1, further comprising a swirling flow forming portion,

the swirling flow forming portion is provided so as to form a swirling flow in the water or aqueous solution flowing in the water flow path,

the gas-liquid mixing section is provided so as to form a swirling flow having the same direction of rotation as the swirling flow formed by the swirling-flow forming section.

4. The spray nozzle according to any one of claims 1 to 3, wherein the first discharge hole and the second discharge hole are arranged on the same plane or are arranged to protrude in the discharge direction from the second discharge hole.

5. The spray nozzle according to any one of claims 1 to 3, wherein the second ejection hole has a circular ring shape,

the outer wall of the second discharge hole is provided so as to protrude in the discharge direction from the first discharge hole.

6. The spray nozzle according to claim 5, wherein the first ejection hole is provided so that the oxidizing gas ejected from the first ejection hole is supplied into the mist outside the spray nozzle.

7. The spray nozzle according to claim 5, wherein a distance between a front end of the outer wall of the second ejection hole and the first ejection hole is greater than 0mm and 2mm or less.

8. The spray nozzle according to claim 6, wherein a distance between a front end of the outer wall of the second ejection hole and the first ejection hole is greater than 0mm and less than 2 mm.

9. The spray nozzle according to any one of claims 1 to 3, further provided with an air discharge hole,

the air discharge hole is provided to discharge air from the air discharge hole to the outside of the spray nozzle, and the air discharge hole is provided to surround a flow path or a second ejection hole through which water, an aqueous solution, or a spray gas is supplied to the second ejection hole.

10. A spray nozzle according to any one of claims 1 to 3 wherein the oxidant gas is an ozone containing gas.

11. A method of spraying comprising the steps of: spraying water or an aqueous solution into the gas to be treated flowing through the gas flow path to be treated to which the spray nozzle according to any one of claims 1 to 10 is attached from the second spraying hole while rotating together with the spraying gas, thereby forming mist in the gas to be treated, and spraying an oxidizing gas from the first spraying hole, thereby supplying the oxidizing gas into the mist.

12. The spraying method according to claim 11, wherein the gas to be treated is an exhaust gas containing NOx,

the oxidant gas is an ozone-containing gas.