A spray gun and a spray drying system

Abstract

The present invention provides a spray gun and a spray drying system, wherein the spray gun comprises a first tube and a nozzle at least partially located in the first tube, and a first flow channel for fluid to flow out is formed between the outer periphery of the nozzle and the first tube. With the above structure, wastewater to be atomized and evaporated will be divided into two paths when flowing through the nozzle, one path entering the nozzle and sprayed into an evaporation tower after atomization, and the other path flowing out from the first flow channel between the outer periphery of the nozzle and the first tube. In this process, wastewater with a lower temperature can flush the nozzle, cool the nozzle, and prevent the nozzle from internal crystallization or scaling due to high temperature.

Description

Technical Field

[0001] The invention relates to the technical field related to wastewater treatment, and in particular to a spray gun and a spray drying system. Background Art

[0002] At present, the desulfurization wastewater from coal-fired power plants is usually treated by thermal evaporation. The thermal evaporation method is to spray the desulfurization wastewater into a high-temperature flue after atomization, and use the waste heat of the flue gas in the high-temperature flue to evaporate it. The atomization and evaporation steps are collectively referred to as the spray drying process.

[0003] The spray drying process includes a spray drying system. The core of the spray drying system is an atomizer. In the prior art, the atomizer usually uses a solid atomizing nozzle, which has a simple structure and low manufacturing cost. The high-temperature smoke tower matched with it has a small tower diameter, and the engineering cost of the overall system is low.

[0004] The atomizing nozzle body usually needs to extend into the high-temperature flue so that the temperature of the part in contact with the high-temperature flue gas is higher. The atomizing nozzle body is small, and the wastewater flow channel inside is also small. The wastewater crystallization or scaling on the wastewater flow channel wall inside the atomizing nozzle is usually caused by the local high temperature. The crystallization or scaling of the flow channel wall will cause the atomization effect to decrease, causing the spray drying system to collapse, or directly block the entire wastewater flow channel, making the spray drying system unable to work.

[0005] Therefore, how to provide a spray drying system in which the nozzle will not be blocked due to crystallization or scaling is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0006] The object of the present invention is to provide a spray gun and a spray drying system in which the inside of the nozzle will not be blocked due to crystallization or scaling.

[0007] To solve the above technical problems, the present invention provides a spray gun, which includes a first tube and a nozzle at least partially located in the first tube, and a first flow channel for fluid to flow out is formed between the outer periphery of the nozzle and the first tube.

[0008] With the above structure, wastewater that needs to be atomized and evaporated will be divided into two paths when flowing through the nozzle. One path enters the nozzle and is sprayed into the evaporation tower after atomization, and the other path flows out from the first flow channel between the outer periphery of the nozzle and the first tube. In this process, the wastewater with lower temperature can flush the nozzle, cool the nozzle, and prevent the nozzle from internal crystallization or scaling due to high temperature.

[0009] Optionally, it further includes a second tube that covers the first tube, a second flow channel is formed between the second tube and the first tube, and the first flow channel is connected to the second flow channel.

[0010] Optionally, it also includes an end cover, the nozzle head of the nozzle is inserted into and fixed to the end cover, the end cover is sealed and fixed to one end of the second tube, a gap is left between the end of the first tube and the end cover, and the first flow channel is connected with the second flow channel through the gap.

[0011] Optionally, one end of the second tube close to the end cover is fixedly connected to the first tube via a plurality of limit blocks, and the other end of the second tube is sealed and fixedly connected to the first tube.

[0012] Optionally, the end cover and the second tube are connected by threads and sealed by a sealing gasket.

[0013] Optionally, the peripheral wall of the second tube is connected to a water outlet pipe, and the fluid flowing through the second flow channel can be discharged through the water outlet pipe.

[0014] Optionally, the water outlet pipe is provided with a water outlet flange, the first pipe includes a water inlet end and a water outlet end provided with the nozzle, the water inlet end is provided with a right-angle bend, and a water inlet flange is provided upstream of the right-angle bend.

[0015] Optionally, there is a nozzle channel in the nozzle, and the flow splitting ratio between the nozzle channel and the second channel is 1:4.

[0016] The present invention also provides a spray drying system, comprising an evaporation tower, a wastewater tank and a pump, and also comprising a spray gun arranged outside the tower wall of the evaporation tower, wherein the spray gun is the spray gun described above.

[0017] Optionally, it further comprises a support tube, wherein the support tube covers the second tube, one end of the support tube is fixedly connected to the second tube via a support flange, and the other end of the support tube is fixedly connected to the tower wall of the evaporation tower.

[0018] Optionally, a back pressure valve is also included, and the wastewater tank, the pump, the spray gun and the back pressure valve are connected in sequence by pipelines to form a wastewater circulation loop. The wastewater in the wastewater tank can be pumped into the first pipe of the spray gun by the pump, and then flows out through the first flow channel and flows through the back pressure valve back to the wastewater tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of an embodiment of the present invention in which a spray gun is arranged on the wall of an evaporation tower;

[0020] Figure 2 yes Figure 1 Schematic diagram of the axial cross-section structure of the middle nozzle position;

[0021] Figure 3 yes Figure 1 An enlarged structural diagram of the middle nozzle position;

[0022] Figure 4 It is a schematic structural diagram of a spray drying system provided by an embodiment of the present invention.

[0023] Figure 1-4 The reference numerals in the figures are described as follows:

[0024] 01 spray gun, 1 nozzle, 2 end cover, 21 gap, 3 first pipe, 31 water inlet flange, 32 first flow channel, 4 second pipe, 5 limit block, 6 outlet pipe, 61 outlet flange, 7 second flow channel, 8 sealing gasket, 9 evaporation tower, 91 tower wall, 10 support pipe, 101 support flange, 11 wastewater tank, 12 pump, 13 back pressure valve. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0026] Please refer to Figure 1-3 , Figure 1 It is a structural schematic diagram of an embodiment of the present invention in which a spray gun is arranged on the wall of an evaporation tower; Figure 2 yes Figure 1 Schematic diagram of the axial cross-section structure of the middle nozzle position; Figure 3 yes Figure 1 Enlarged structural diagram of the nozzle position.

[0027] The present invention provides a spray gun 01, which is specifically arranged on the tower wall 91 of the evaporation tower 9. In practice, the tower wall 91 of the evaporation tower 9 is usually a multi-layer structure due to reasons such as heat preservation and corrosion protection. For example, it is divided into an inner wall, a heat preservation layer, an air layer, and an outer protective layer. In this embodiment, the front end of the spray gun 01 can be integrally inserted into the multi-layer structure of the tower wall 91, and only the end is in contact with the inside of the evaporation tower 9. The specific structure of the evaporation tower 9 shall prevail. For the convenience of description, Figure 1 , Figure 3 And hereinafter, the tower wall 91 refers to the inner wall only.

[0028] The spray gun 01 comprises a first tube 3 and a nozzle 1 at least partially located in the first tube 3 , and a first flow channel 32 for allowing fluid to flow out is formed between the outer periphery of the nozzle 1 and the first tube 3 .

[0029] With the above structure, wastewater that needs to be atomized and evaporated will be divided into two paths when it flows through the nozzle 1. One path enters the nozzle 1, is atomized and sprayed into the evaporation tower 9 for evaporation, and the other path flows out from the first flow channel 32 between the outer periphery of the nozzle 1 and the first tube 3. In this process, while the wastewater flows through the first flow channel 32 and is discharged, it can also flush the outer periphery of the nozzle 1. Moreover, when the wastewater flows through the end of the first flow channel 32, it also flushes the end of the spray gun 01 close to the inner cavity of the evaporation tower 9, and can also form strong turbulence. Then, the wastewater with a lower temperature can cool the nozzle 1 and prevent the nozzle 1 from internal crystallization or scaling due to high temperature. The nozzle 1 can be in the first tube 3 as much as possible, Figure 3 In the embodiment, most of the nozzle 1 is in the first pipe 3. The size of the first flow channel 32 should be moderate, and the design is carried out for the purpose of ensuring smooth discharge of cooling waste water and sufficient cooling of the nozzle 1.

[0030] Furthermore, the spray gun 01 further includes a second tube 4 which is sleeved with the first tube 3, that is, the first tube 3 is an inner tube, the second tube 4 is an outer tube, a second flow channel 7 is formed between the second tube 4 and the first tube 3, and the first flow channel 32 is connected to the second flow channel 7. Wastewater for heat exchange cooling of the nozzle 1 can flow from the first flow channel 32 into the second flow channel 7, so that the wastewater for cooling is discharged and convenient for entering the subsequent wastewater circulation.

[0031] This embodiment also includes an end cap 2, the nozzle of the nozzle 1 is inserted into and fixed to the end cap 2, the end cap 2 is sealed and fixed to one end of the second tube 4, and a gap 21 is left between the end of the first tube 3 and the end cap 2. The gap 21 is annular, and the first flow channel 32 can be connected with the second flow channel 7 through the gap 21. When the cooling wastewater flows to the gap 21 through the first flow channel 32, a strong turbulence is formed on the side of the end cap 2 close to the first inner tube 3, and the end cap 2 is efficiently heat exchanged. While cooling the end cap 2, the temperature of the nozzle of the nozzle 1 inserted in the end cap 2 is reduced.

[0032] It can be understood that there are many ways to set up the cooling waste water to be discharged through the first flow channel 32. The above gap 21 setting method is only the method adopted in this embodiment. In practical applications, other methods can also be adopted. For example, no end cover 2 is provided, and the ends of the first tube 3 and the second tube 4 are directly sealed. Only the nozzle of the nozzle 1 leaks out and contacts with the inside of the evaporation tower 9. A plurality of water outlets are provided at positions near the end of the first tube 3. The water outlets can connect the first flow channel 32 and the second flow channel 7. After the waste water cools the nozzle 1, it can flow into the second flow channel 7 from the water outlet holes.

[0033] Alternatively, the second tube 4 is not provided, and the end cover 2 is directly sealed and connected to the end of the first tube 3. A water outlet pipeline is provided on one side of the first tube 3 near the end, and the water outlet pipeline directly leads out the waste water of the cooling nozzle 1 flowing through the first flow channel 32. There are other ways, which are not described in detail in this article. As long as the cooling waste water of the first flow channel 32 can be discharged, the second tube 4 is provided in this embodiment to form a second flow channel 7, so as to facilitate the cooling waste water flowing out of the first flow channel 32 to the outside of the cooling tower 9; an annular gap 21 is formed to achieve the connection between the first flow channel 32 and the second flow channel 7 in a relatively simple manner. Moreover, when the waste water flows out of the annular gap 21, the flow rate is large, and it is easier to form turbulence at the end of the first inner tube 3, which is convenient for efficient heat exchange, flushing the end cover 2, and efficient cooling.

[0034] In this embodiment, Figure 3 As shown, one end of the second tube 4 close to the end cover 2 is fixedly connected to the first tube 3 through a plurality of limit blocks 5, and the other end is sealed and fixedly connected to the first tube 3. Figure 2 As shown, three stoppers 5 are evenly arranged between the first tube 3 and the second tube 4 in the circumferential direction, and the ends of the first tube 3 and the second tube 4 are fixed by the stoppers 5. Since there is a gap 21 between the first tube 3 and the end cover 2, the end of the first tube 3 close to the end cover 2 is in a suspended state. The stoppers 5 are arranged to prevent the first tube 3 from shaking in the second tube 4, further ensuring the stability and uniformity of the hydraulic flow field. Of course, the stoppers 5 can also be other numbers and shapes, as long as the stoppers 5 can prevent the first tube 3 from shaking in the second tube 4 and do not affect the wastewater from entering the second flow channel 7 from the flow channel.

[0035] Specifically, the end cap 2 and the second tube 4 can be connected by threads and sealed by a sealing gasket 8. This connection method can make the connection between the end cap 2 and the second tube 4 more stable. The sealing gasket 8 can be made of NBR (i.e., nitrile rubber) or PTFE (i.e., polytetrafluoroethylene) material.

[0036] Please continue to refer to Figure 1 The side wall of the second tube 4 at one end away from the end cover 2 is connected to a water outlet pipe 6 , and the fluid flowing through the second flow channel 7 can be discharged through the water outlet pipe 6 .

[0037] This embodiment further includes a support tube 10, which penetrates the tower wall 91 of the evaporation tower 9, and the second tube 4 of the spray gun 01 is inserted into the support tube 10. One end of the support tube 10 is fixedly connected to the second tube 4 through a support flange 101, and the other end is fixedly connected to the tower wall 91 of the evaporation tower 9. In this arrangement, when the support flange 101 is opened, the spray gun 01 can be pulled out of the evaporation tower 9 as a whole, which is convenient for inspection and maintenance.

[0038] like Figure 1As shown, the water outlet pipe 6 is provided with a water outlet flange 61, the first pipe 3 includes a water inlet end and a water outlet end provided with a nozzle 1, a right-angle bend is provided at the water inlet end, and a water inlet flange 31 is provided upstream of the right-angle bend. When the water outlet flange 61, the water inlet flange 31 and the support flange 101 are opened at the same time, the spray gun 01 can be separated from the wastewater treatment system as a whole, which is further convenient for maintenance and other operations. The purpose of setting the right-angle bend in the first pipe 3 in this embodiment is to make the directions of the water inlet flange 31 and the water outlet flange 61 consistent. When the spray gun 01 is separated from the wastewater treatment system as a whole, the separation directions of the water inlet flange 31 and the water outlet flange 61 are consistent, which is convenient for the spray gun 01 to be disengaged. Of course, the first pipe 3 may not be provided with a right-angle bend, and the water inlet flange 31 may be directly provided, or a pipeline with other bending angles may be provided, as long as it can cooperate with the water outlet flange 61 and the support flange 101 to disengage the spray gun 01 as a whole.

[0039] In this embodiment, the nozzle 1 contains a nozzle flow channel, and the flow splitting ratio between the nozzle flow channel and the second flow channel 7 can be 1:4. Figure 3 As shown, Figure 3 The direction of the middle arrow is the flow direction of the wastewater in the first tube 3, the first flow channel 32 and the second flow channel 7. Under this diversion ratio, since the nozzle 1 can always be in a water bath state and the amount of water used for cooling is large, the nozzle 1 can obtain a better cooling effect and achieve the effect of no crystallization or scaling. One side of the end cover 2 faces the inner cavity of the evaporation tower 9, and local temperature rise may also occur, resulting in a small amount of crystallization or scaling. Whether it is the end cover 2 or the nozzle 1, even if a small amount of crystallization or scaling occurs, it will be washed away by a large amount of water and will not cause blockage of the flow channels. Of course, the above-mentioned diversion ratio can be adjusted. By changing the cross-sectional specifications of the first tube 3 and the second tube 4, the flow area of ​​the first flow channel 32 and the second flow channel 7 is changed, and the diversion ratio of the nozzle flow channel and the second flow channel 7 can be changed.

[0040] Please refer to Figure 4 , Figure 4 It is a schematic structural diagram of a spray drying system provided by an embodiment of the present invention.

[0041] The present invention further provides a spray drying system, comprising an evaporation tower 9, a wastewater tank 11 and a pump 12, and also comprising a spray gun 01 arranged outside the tower wall 91 of the evaporation tower 9, and the spray gun 01 is the spray gun 01 described above. Since the spray gun 01 has the technical effects described above, the spray drying system including the spray gun 01 should also have the same technical effects, so it will not be described here in detail.

[0042] The evaporation tower 9 is a container for wastewater to exchange heat with high-temperature flue gas for evaporation. The wastewater tank 11 stores wastewater to be evaporated and wastewater refluxed after cooling the nozzle 1. The pump 12 sucks the wastewater out of the wastewater tank 11 and pumps it into the first tube 3 of the spray gun 01.

[0043] This embodiment also includes a back pressure valve 13. The wastewater tank 11, the pump 12, the spray gun 01 and the back pressure valve 13 are connected in sequence through pipes to form a wastewater circulation loop. The wastewater in the wastewater tank 11 can be pumped into the first pipe 3 of the spray gun 01 through the pump 12, and then the wastewater flows through the outlet pipe 6 and the back pressure valve 13 back to the wastewater tank 11.

[0044] It should be noted that in this process, the back pressure valve 13 can provide a suitable pressure for the wastewater diversion. In the two branches of the diversion, the wastewater flowing through the nozzle flow channel needs to be atomized, and the required pressure is relatively high. The wastewater flowing through the first flow channel 32 only needs to flow back to the wastewater tank 11, and the pressure is relatively low. If the back pressure valve 13 is not set, the wastewater flowing from the water inlet end of the first pipe 3 to the diversion point will directly flow to the first flow channel 32 with lower pressure, and then flow back to the wastewater tank 11 through the second flow channel 7. Since the pressure at the diversion point is very low, only a small part of the wastewater will flow into the nozzle flow channel and be sprayed into the evaporation tower 9 in a non-atomized state, and the purpose of diversion and atomization cannot be achieved.

[0045] After the back pressure valve 13 is set, after the wastewater flows into the first pipe 3, the back pressure valve 13 is appropriately reduced to increase the pressure at the diversion point. The wastewater can be diverted at the diversion point according to the flow area of ​​the first flow channel 32 and the nozzle flow channel, and the desired atomization effect can be obtained at the same time.

[0046] After the pump 12 is turned on, the wastewater is sucked out of the wastewater tank 11 by the pump 12 and pumped into the first pipe 3 of the spray gun 01. The wastewater is split at the nozzle 1. One part enters the nozzle flow channel in the nozzle 1 and is sprayed into the evaporation tower 9 in atomization. The other part cools the nozzle 1 and the end cover 2 through the first flow channel 32, and then enters the second flow channel 7 through the gap 21 and is discharged from the spray gun 01 through the outlet pipe 6. When the wastewater fills the inside of the spray gun 01, the pressure of the wastewater flowing through the first flow channel 32 can be increased or decreased by adjusting the back pressure valve 13 at the outlet end, thereby adjusting the flow rate and the split ratio of the first flow channel 32 and the nozzle flow channel.

[0047] After cooling the nozzle 1 and the end cover 2, the wastewater flows back to the wastewater tank 11. In this process, since the area of ​​the end cover 2 itself is very small, the heat carried by the wastewater in the second flow channel 7 after heat exchange cooling is very small. The wastewater can naturally dissipate heat and cool to a lower temperature, and the next wastewater cycle can be carried out directly. The spray drying system does not need to set up an additional cooling system.

[0048] Please refer to Figure 4The arrow in the pipeline is the flow direction of the wastewater, the direction above the evaporation tower 9 is the flow direction of the high-temperature flue gas, the right side below is the flow direction of the low-temperature flue gas, and the bottom is the discharge direction of the solid waste. The high-temperature flue gas enters the evaporation tower 9 from the top of the evaporation tower 9, contacts and exchanges heat with the wastewater sprayed into the evaporation tower 9, evaporates the wastewater, and the high-temperature flue gas is cooled to low-temperature flue gas and discharged from one side of the evaporation tower 9. The solid waste generated by the evaporation of the wastewater is discharged from the bottom of the evaporation tower 9.

[0049] The present invention also provides a wastewater evaporation method based on a spray drying system. The spray drying system is the spray drying system described above. The technical effects of the two are the same and will not be repeated here.

[0050] The specific steps of this method are as follows:

[0051] Turn on the pump 12 to pump the wastewater in the wastewater tank 11 into the first pipe 3 of the spray gun 01. The wastewater flows to the nozzle 1 through the first pipe 3. Part of the wastewater enters the nozzle flow channel in the nozzle 1 and is atomized and sprayed into the evaporation tower 9. Part of the wastewater flows into the second flow channel 7 between the first pipe 3 and the second pipe 4 through the first flow channel 32 between the end cover 2 and the first pipe 3. At the same time, the nozzle 1 and the end cover 2 are cooled;

[0052] The wastewater flowing into the second flow channel 7 flows to the outlet pipe 6 and flows back to the wastewater tank 11 through the back pressure valve 13. Controlling the size of the back pressure valve 13 can control the pressure of the wastewater in the first pipe 3 and the second flow channel 7, so as to control the flow rate of the wastewater flowing to the nozzle flow channel in the nozzle 1 and the first flow channel 32.

[0053] In the above embodiment, the cooling fluid is waste water, and may also be other cooling media. In addition, the spray gun 01 is inserted into the evaporation tower 9 to cool the high-temperature flue gas. It can be seen that the spray gun 01 is not limited to being inserted into the evaporation tower 9, but may also be applicable to other high-temperature environments where the spray gun 01 is required to spray liquid. In this case, the nozzle of the spray gun 01 faces the problem of high-temperature scaling and crystallization. In this case, the self-cooling function of the spray gun 01 in this solution can solve this problem.

[0054] The above are only preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A spray gun, characterized in that: The spray gun (01) comprises a first tube (3) and a nozzle (1) at least partially located in the first tube (3), a first flow channel (32) for fluid to flow out is formed between the outer periphery of the nozzle (1) and the first tube (3), and an inlet of the nozzle (1) is located in the first tube (3); It also comprises a second tube (4) which is outer-sheathed around the first tube (3), and a second flow channel (7) is formed between the second tube (4) and the first tube (3); It also comprises an end cover (2), a nozzle of the nozzle (1) is inserted into and fixed to the end cover (2), an outlet of the nozzle (1) is located outside the first tube (3) and the second tube (4), the end cover (2) is sealed and fixed to one end of the second tube (4), a gap (21) is left between the end of the first tube (3) and the end cover (2), and the first flow channel (32) is connected to the second flow channel (7) through the gap (21); The peripheral wall of the second tube (4) is connected to a water outlet pipe (6), and the fluid flowing through the second flow channel (7) can be discharged through the water outlet pipe (6).

2. The spray gun according to claim 1, characterized in that: One end of the second tube (4) close to the end cover (2) is fixedly connected to the first tube (3) via a plurality of limit blocks (5), and the other end is sealed and fixedly connected to the first tube (3).

3. The spray gun according to claim 2, characterized in that: The end cover (2) and the second tube (4) are connected by threads and sealed by a sealing gasket (8).

4. The spray gun according to claim 1, characterized in that: The water outlet pipe (6) is provided with a water outlet flange (61), the first pipe (3) comprises a water inlet end and a water outlet end provided with the nozzle (1), the water inlet end is provided with a right-angle bend, and a water inlet flange (31) is provided upstream of the right-angle bend.

5. The spray gun according to any one of claims 1 to 4, characterized in that: The nozzle (1) contains a nozzle flow channel, and the flow splitting ratio between the nozzle flow channel and the second flow channel (7) is 1:

4.

6. A spray drying system, comprising an evaporation tower (9), a waste water tank (11) and a pump (12), characterized in that: It also comprises a spray gun (01) arranged on the outside of the tower wall (91) of the evaporation tower (9), and the spray gun (01) is the spray gun (01) according to any one of claims 1 to 5.

7. The spray drying system according to claim 6, characterized in that: It also comprises a support tube (10), wherein the support tube (10) is sheathed around the second tube (4), one end of the support tube (10) is fixedly connected to the second tube (4) via a support flange (101), and the other end of the support tube (10) is fixedly connected to the tower wall (91) of the evaporation tower (9).

8. The spray drying system according to claim 7, characterized in that: It also includes a back pressure valve (13); the waste water tank (11), the pump (12), the spray gun (01) and the back pressure valve (13) are connected in sequence through a pipeline to form a waste water circulation loop; the waste water in the waste water tank (11) can be pumped into the first pipe (3) of the spray gun (01) by the pump (12), and then flows out through the first flow channel (32) and flows through the back pressure valve (13) back to the waste water tank (11).

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