Three-way flue with blind plate switching function and flue gas treatment system

Abstract

The invention relates to a three-way flue with a blind plate switching function and a flue gas treatment system provided with the three-way flue, the three-way flue comprises a flue gas inlet section and two flue gas outlet sections, gate valves are arranged on the two flue gas outlet sections, and the two gate valves share one gate plate assembly. The flashboard assembly comprises a blind plate and a pore plate, the pore plate is a flashboard with a through hole, the blind plate is selectively inserted into one valve seat, and the pore plate is inserted into the other valve seat; and the three-way flue is provided with a blind plate switching execution mechanism for switching the blind plate and the pore plate. In the invention, two groups of gate valves are designed to share one group of gate assembly, and smoke can only be discharged from one smoke outlet section instead of being discharged from two smoke outlet sections at the same time, so that the operation reliability is ensured, and the condition of misoperation is avoided; and the blind plate and the pore plate are adopted for switching, so that the sealing performance of the two groups of gate valves can be ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of flue gas treatment, and particularly relates to a three-way flue with a blind plate switching function and a flue gas treatment system configured with the three-way flue. Background Art

[0002] In a waste heat recovery system, a three-way flue is a common pipeline configuration used to divert or combine flue gas to meet different process requirements, achieving effects such as optimizing flue gas flow and improving heat recovery efficiency. Such a three-way flue is generally an adiabatic flue, and the main application scenarios include:

[0003] (1) Multiple waste heat boilers in parallel: Diverting flue gas to multiple boilers to improve the system processing capacity;

[0004] (2) Flue gas bypass: When the main equipment fails or is under maintenance, switching the flue gas to the bypass to ensure continuous operation of the system;

[0005] (3) Flue gas mixing: Mixing flue gas at different temperatures and adjusting it to a suitable temperature before entering the heat recovery equipment.

[0006] When the three-way flue is in use, cut-off valves can be configured at the two flue gas outlet sections respectively to control the flue gas flow direction. A gate valve is a relatively commonly used cut-off valve. Usually, gates are respectively configured for the two cut-off valves to control their respective on-off states. For the situation where only the flue gas is allowed to be discharged from one of the flue gas outlet sections (for example, when applied to a flue gas bypass), the above method may have the situation of misoperation. Summary of the Invention

[0007] The present invention relates to a three-way flue with a blind plate switching function and a flue gas treatment system configured with the three-way flue, which can at least solve some defects of the prior art.

[0008] The present invention relates to a three-way flue with a blind plate switching function, which includes a flue gas inlet section and two flue gas outlet sections. Plug valves are provided on both of the two flue gas outlet sections, and two groups of plug valves share a set of gate components. The gate components include a blind plate and an orifice plate. Among them, the orifice plate is a gate plate with a through hole. The blind plate is alternatively inserted into one of the valve seats, and the orifice plate is inserted into the other valve seat; the three-way flue is configured with a blind plate switching actuator for swapping the blind plate and the orifice plate.

[0009] As one of the implementation manners, define the valve seats of the two plug valves as the first valve seat and the second valve seat respectively;

[0010] The blind plate switching actuator includes an annular switching track and two sets of lifting devices movably arranged on the annular switching track. Among them, the annular switching track includes a first normal track section directly above the first valve seat, a second normal track section directly above the second valve seat, and a transfer track section connecting the first normal track section and the second normal track section. The guiding direction of the first normal track section is perpendicular to the axial direction of the first valve seat, and the guiding direction of the second normal track section is perpendicular to the axial direction of the second valve seat.

[0011] As one of the implementation manners, the transfer track section includes two first extension track sections, two second extension track sections, and two relay track sections. Among them,

[0012] The two first extension track sections are respectively connected to both ends of the first normal track section, and the guiding directions of the two first extension track sections are parallel to the guiding direction of the first normal track section;

[0013] The two second extension track sections are respectively connected to both ends of the second normal track section, and the guiding directions of the two second extension track sections are parallel to the guiding direction of the second normal track section;

[0014] The first extension track section and the second extension track section on the same side are connected by a relay track section.

[0015] As one of the implementation manners, the sum of the lengths of the first normal track section and the two first extension track sections L1≥3D, where D is the outer diameter of the blind plate.

[0016] As one of the implementation manners, the sum of the lengths of the second normal track section and the two second extension track sections L2≥3D, where D is the outer diameter of the blind plate.

[0017] As one of the implementation manners, the lifting device adopts a lifting hoist.

[0018] As one of the implementation manners, the annular switching track is installed on the flue through a bracket, or installed on the foundation or equipment around the flue.

[0019] As one of the implementation manners, both the blind plate and the orifice plate are water-cooled gate plates.

[0020] As one of the implementation manners, the flue gas inlet section and the two flue gas outlet sections both adopt the form of vaporization cooling flue.

[0021] The present invention also provides a flue gas treatment system, including a vaporization cooling flue, and further configured with a three-way flue as described above. The flue gas inlet section is connected to the vaporization cooling flue, and the two flue gas outlet sections are respectively connected with flue gas treatment mechanisms.

[0022] The present invention has at least the following beneficial effects:

[0023] In the present invention, two sets of flap valves share one set of gate plate assemblies. The flue gas can only be discharged from one of the flue gas outlet sections, rather than being discharged from both flue gas outlet sections simultaneously, ensuring the reliability of operation and avoiding misoperation. The use of a blind plate and an orifice plate for switching can ensure the sealing performance at the two sets of flap valves. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] Figure 1 Structural schematic diagram of the converter gas recovery system provided by an embodiment of the present invention;

[0026] Figure 2 Structural schematic diagram of the waste heat boiler provided by an embodiment of the present invention;

[0027] Figure 3 Structural schematic diagram of the first-return boiler provided by an embodiment of the present invention;

[0028] Figure 4 Structural schematic diagram of the three-way flue provided by an embodiment of the present invention;

[0029] Figure 5 Structural schematic diagram of the annular switching track provided by an embodiment of the present invention;

[0030] Figure 6 and Figure 7 Structural schematic diagram of the water-cooled blind plate provided by an embodiment of the present invention;

[0031] Figure 8 Structural schematic diagram of the blind plate body of the water-cooled blind plate;

[0032] Figure 9 Structural schematic diagram of the water-cooled orifice plate provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] The following clearly and completely describes the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0034] Embodiment 1

[0035] As Figure 4and Figure 5 In an embodiment of the present invention, a three-way flue 2 with a blind plate switching function is provided, which includes a flue gas inlet section 21 and two flue gas outlet sections 22. Plug valves 3 are provided on both of the two flue gas outlet sections 22, and the two groups of plug valves 3 share a set of gate assemblies. The gate assembly includes a blind plate 30a and an orifice plate 30b. Among them, the orifice plate 30b is a gate plate with a through hole. The blind plate 30a is alternatively inserted into one of the valve seats, and the orifice plate 30b is inserted into the other valve seat; the three-way flue 2 is configured with a blind plate switching actuator for swapping the blind plate 30a and the orifice plate 30b.

[0036] When the blind plate 30a is inserted into one of the valve seats, this plug valve 3 is in the closed state, and the other plug valve 3 is in the open state because the orifice plate 30b is used at the valve seat. Based on this solution, the flue gas can only be discharged from one of the flue gas outlet sections 22, and will not be discharged from the two flue gas outlet sections 22 simultaneously, ensuring the operation reliability and avoiding misoperation. Using the blind plate 30a and the orifice plate 30b for switching can ensure the sealing performance at the two groups of plug valves 3.

[0037] For ease of description, the valve seats of the two plug valves 3 are defined as the first valve seat and the second valve seat respectively.

[0038] Such as Figure 5 shown, the blind plate switching actuator includes an annular switching track 8 and two sets of lifting devices movably arranged on the annular switching track 8. Among them, the annular switching track 8 includes a first normal track section 81 directly above the first valve seat, a second normal track section 82 directly above the second valve seat, and a transfer track section connecting the first normal track section 81 and the second normal track section 82. The guiding direction of the first normal track section 81 is perpendicular to the axial direction of the first valve seat, and the guiding direction of the second normal track section 82 is perpendicular to the axial direction of the second valve seat.

[0039] The above-mentioned lifting device is used to lift the gate plate 30 of one of the plug valves 3, and then move on the annular switching track 8 to the other valve seat for installation; and the annular switching track 8 can ensure the smoothness of the relative movement of the blind plate 30a and the orifice plate 30b. The blind plate 30a and the orifice plate 30b can move synchronously to the target position for installation, thereby improving the maintenance efficiency and saving maintenance time.

[0040] The above-mentioned lifting device includes, but is not limited to, a lifting hoist, which can be a manual hoist or an electric hoist.

[0041] Preferably, as Figure 5 shown, the transfer track section includes two first extension track sections 83, two second extension track sections 84, and two relay track sections 85, among which,

[0042] Two first extended track segments 83 are respectively connected to two ends of the first main track segment 81. The guiding directions of the two first extended track segments 83 are both parallel to the guiding direction of the first main track segment 81, which can improve the smoothness and reliability of the gate replacement at the first valve seat;

[0043] Two second extended track segments 84 are respectively connected to two ends of the second main track segment 82. The guiding directions of the two second extended track segments 84 are both parallel to the guiding direction of the second main track segment 82, which can improve the smoothness and reliability of the gate replacement at the second valve seat;

[0044] The first extended track segment 83 and the second extended track segment 84 on the same side are connected by a relay track segment 85.

[0045] Preferably, the sum of the lengths of the first main track segment 81 and the two first extended track segments 83, L1≥3D, where D is the outer diameter of the blind plate 30a, to ensure that the blind plate 30a / orifice plate 30b can be smoothly pushed out and pushed in; Similarly, the sum of the lengths of the second main track segment 82 and the two second extended track segments 84, L2≥3D, to ensure that the blind plate 30a / orifice plate 30b can be smoothly pushed out and pushed in.

[0046] Wherein, the annular switching track 8 is installed on the three-way flue 2 through a bracket, or installed on a foundation or equipment around the three-way flue 2.

[0047] Preferably, both the blind plate 30a and the orifice plate 30b are water-cooled gates 30, which have good high-temperature resistance, so that the above three-way flue 2 can be applicable to the transportation of high-temperature gases such as flue gas.

[0048] Embodiment 2

[0049] This embodiment provides a water-cooled blind plate 30a, which can be used in the above Embodiment 1.

[0050] As Figures 6 - 8 , the water-cooled blind plate 30a includes a blind plate body 301, and a water-cooling unit is arranged inside the blind plate body 301 to ensure that the blind plate body 301 can withstand high-temperature environments.

[0051] Optionally, the water-cooling unit includes, but is not limited to, one or more of cooling channels such as a spiral cooling water path and a serpentine cooling water path, and the cooling water inlet main pipe and the return water main pipe can be one or more. Among them, when the water-cooling unit adopts water-cooling pipes, these water-cooling pipes constitute a part of the blind plate body 301; the blind plate body 301 with a circular structure can be formed only by these water-cooling pipes, or the blind plate body 301 can further include other components, such as fixing these water-cooling pipes on a substrate.

[0052] Among them, the water inlet end 305 and the water return end 307 of the water cooling unit are located outside the outer peripheral edge of the blind plate body 301, so as to facilitate connection with the water inlet pipe and the water return pipe.

[0053] Further preferably, refractory material layers 302 are respectively cast on both sides of the blind plate body 301, further improving the high-temperature resistance and weather resistance of the water-cooled blind plate 30a, preferably protecting the blind plate body 301, and greatly extending the service life of the water-cooled blind plate 30a; moreover, the maintenance cost of the refractory material layer 302 is low and very convenient, which can significantly reduce the maintenance cost of the water-cooled blind plate 30a. In one embodiment, a plurality of expansion joints are formed in the refractory material layer 302, and the expansion joints include but are not limited to being formed by embedding refractory aluminosilicate fiber felts or other refractory soft materials in the refractory material, so as to improve the thermal expansion and cold expansion performance of the refractory material layer 302, and can preferably meet the working conditions of discontinuous generation of flue gases such as converter gas.

[0054] Further preferably, anchoring claw nails are respectively provided on both sides of the blind plate body 301, which can improve the bonding reliability between the refractory material layer 302 and the blind plate body 301.

[0055] In one embodiment, a connecting flange is provided on the outer peripheral edge of the blind plate body 301, and the connecting flange is used to connect with the valve seat flange.

[0056] Preferably, an annular sealing cavity 304 is formed on the outer peripheral edge of the blind plate body 301, and a sealing component is embedded in the sealing cavity 304. The sealing component includes but is not limited to using a sealing rope.

[0057] In one embodiment, as Figure 6 and Figure 7 , at least a purging unit 303 is provided on the air-facing surface of the blind plate body 301, which can perform protective purging on the air-facing surface, including but not limited to purging with nitrogen. Preferably, the purging unit 303 includes a purging main pipe 3031 and a plurality of short pipe nozzles 3032 connected to the purging main pipe 3031. The purging main pipe 3031 is buried in the refractory material layer 302 on the air-facing side, and the nozzles of the short pipe nozzles 3032 are flush with the outer surface of the refractory material layer 302. Among them, the purging main pipe 3031 is configured as a plurality of annular distribution pipes, and a plurality of short pipe nozzles 3032 are arranged on each annular distribution pipe, so that the short pipe nozzles 3032 are distributed to form a plurality of nozzle rings; the purging main pipe 3031 can also be distributed in a branched shape, and a plurality of short pipe nozzles 3032 are respectively arranged on each branch.

[0058] Among them, the air inlet end 306 of the purging main pipe 3031 extends outside the outer peripheral edge of the blind plate body 301, so as to facilitate connection with the relevant gas source.

[0059] Further preferably, as Figure 6, the purging direction of the short pipe nozzle 3032 is inclined relative to the axis of the blind plate body 301. This way can improve the protection purging effect and reduce the probability of blockage of the short pipe nozzle 3032; it is further preferably that the purging direction of the short pipe nozzle 3032 faces the axis of the blind plate body 301.

[0060] The above-mentioned purging main pipe 3031 is preferably fixedly connected to the blind plate body 301. Understandably, the setting of the purging main pipe 3031, especially each short pipe nozzle 3032, can act as an anchor, effectively improving the bonding reliability between the refractory material layer 302 and the blind plate body 301; at the same time, the refractory material layer 302 can reliably protect these purging units 303.

[0061] In one embodiment, the refractory material on the gas-facing surface of the blind plate body 301 is a permeable refractory material. For example, the refractory material layer 302 on the gas-facing surface includes a first refractory layer and a second refractory layer located outside the first refractory layer. The second refractory layer is a permeable refractory material, and the air permeability of the first refractory layer is lower than that of the second refractory layer; the above-mentioned purging main pipe 3031 can be arranged in the first refractory layer or in the second refractory layer. A plurality of air outlets can be arranged on the purging main pipe 3031 facing the second refractory layer for supplying gas to the second refractory layer; alternatively, a gas supply pipe for supplying gas to the second refractory layer can be provided separately. Based on the above solution, under the action of the gas passing through the second refractory layer, the dust on the gas-facing surface can be blown off or peeled off, thereby improving the protection purging effect; in addition, by supplying gas to the second refractory layer, it can also play a role in cooling the refractory material layer 302, better protecting the water-cooled blind plate 30a. Cooling gas (preferably an inert gas, such as low-temperature nitrogen) can be supplied to the second refractory layer under specific working conditions / abnormal working conditions where high-temperature / ultra-high-temperature flue gas may be generated.

[0062] Optionally, as Figure 9 , on the basis of the above-mentioned water-cooled blind plate 30a, the blind plate body 301 and the refractory material layers 302 on both sides are hollowed out according to a set diameter to form a through hole, and then the water-cooled orifice plate 30b can be obtained. The water-cooled orifice plate 30b can be used in the first embodiment above; wherein, preferably, the diameter of the through hole is smaller than the diameters of the blind plate body 301 and the refractory material layer 302.

[0063] Embodiment Three

[0064] This embodiment provides a three-way flue 2, and the three-way flue 2 can be used as an optimization of the first embodiment above.

[0065] As Figure 4The three-way flue 2 includes a flue gas inlet section 21 and two flue gas outlet sections 22, wherein the flue gas inlet section 21 and the two flue gas outlet sections 22 are both in the form of vaporization cooling flues, that is, the flue gas inlet section 21 and the flue gas outlet section 22 are both surrounded by a plurality of vaporization cooling pipes to form corresponding flues.

[0066] In one embodiment, part of the vaporization cooling pipe of the smoke inlet section 21 is coupled with one of the smoke outlet sections 22 to form a first heating surface, and the rest of the vaporization cooling pipe of the smoke inlet section 21 is coupled with another smoke outlet section 22 to form a second heating surface; for example: the left half of the smoke inlet section 21 is coupled with the smoke outlet section 22 on its left side to form the first heating surface, and the right half of the smoke inlet section 21 is coupled with the smoke outlet section 22 on its right side to form the second heating surface. Based on the above design, the number of steam-water pipes can be reduced, which is convenient for on-site implementation.

[0067] For the convenience of description, the vaporization cooling pipeline of the smoke inlet section 21 is defined as the first cooling pipeline 211 , and the vaporization cooling pipeline of the smoke outlet section 22 is defined as the second cooling pipeline 221 .

[0068] For the coupling between the vaporization cooling pipes, the vaporization cooling pipes are connected to form a water path. For example, cooling water enters from one end of the first vaporization cooling pipe, passes through the first cooling pipe 211 and the coupled second vaporization cooling pipe in turn for heat exchange, and then is discharged from the second vaporization cooling pipe to form cooling return water.

[0069] Further preferably, each first cooling pipe 211 is coupled to a plurality of second cooling pipes 221, including but not limited to one first cooling pipe 211 coupled to two second cooling pipes 221. For a structure in which one first cooling pipe 211 is coupled to two second cooling pipes 221, preferably, as Figure 4 , a Y-shaped trousers tube 23 is used to complete the coupling, and the two trouser legs of the Y-shaped trousers tube 23 are respectively connected to the two second cooling pipes 221, and the other end of the Y-shaped trousers tube 23 is connected to the first cooling pipe 211. Based on the above structure, reliable coupling between the smoke inlet section 21 and the smoke outlet section 22 can be achieved, and a reasonable heating surface can be designed to ensure the vaporization cooling effect and heating uniformity of each part of the three-way flue 2.

[0070] Wherein, the adjacent Y-shaped trousers tubes 23 may be sealed by using a flat steel partition or the like.

[0071] Among them, the first heating surface is provided with one or more water inlet headers and one or more water return headers. Preferably, the number of the water inlet headers and the water return headers is the same and they are arranged in one-to-one correspondence. For example, in the structure where the left half of the flue gas inlet section 21 is coupled with the flue gas outlet section 22 on its left to form the first heating surface, each first cooling pipe 211 in the upper half can share one water inlet header, and each second cooling pipe 221 can share one water return header. Each first cooling pipe 211 in the lower half can share one water inlet header, and each second cooling pipe 221 can share one water return header. Moreover, the two water inlet headers are connected to the same water inlet pipe, and the two water return headers are connected to the same water return pipe. The second heating surface can adopt the same water inlet and return water configuration method.

[0072] In another embodiment, the following heating surface composition form can be adopted: a part of the vaporization cooling pipes in the flue gas inlet section 21 is coupled with the lower half of one of the flue gas outlet sections 22 to form the 1# heating surface, the remaining vaporization cooling pipes in the flue gas inlet section 21 are coupled with the lower half of the other flue gas outlet section 22 to form the 2# heating surface, and the upper halves of the two flue gas outlet sections 22 are coupled to form the 3# heating surface.

[0073] Embodiment 4

[0074] Such as Figure 1 , this embodiment provides a flue gas treatment system, including a vaporization cooling flue 1, and further configured with a three-way flue 2 as described above. The flue gas inlet section 21 is connected to the vaporization cooling flue 1, and two flue gas outlet sections 22 are respectively connected with flue gas treatment mechanisms.

[0075] Among them, the flue gas can selectively enter one of the flue gas treatment mechanisms for treatment, with high process flexibility, which can ensure the treatment effect of the flue gas, as well as improve the reliability and safety of flue gas treatment; the two flue gas treatment mechanisms can be used as spares for each other. When one mechanism is out of service, it can be switched to the other mechanism for treatment. Therefore, it is convenient for the overhaul and maintenance of the flue gas treatment mechanism.

[0076] In one of the embodiments, the above flue gas treatment system is used for the treatment of converter gas, and the above vaporization cooling flue 1 is connected to the converter.

[0077] Define the two flue gas treatment mechanisms as the first flue gas treatment mechanism and the second flue gas treatment mechanism respectively.

[0078] Optionally, such as Figure 1 , the first flue gas treatment mechanism includes an evaporation cooler 7, and the flue gas inlet of the evaporation cooler 7 is communicated with one of the flue gas inlet sections 21. Further, a first dust collector is connected to the flue gas outlet side of the evaporation cooler 7, and the first dust collector is connected to downstream equipment; the above first dust collector includes, but is not limited to, an inertial dust collector.

[0079] In one embodiment, as Figure 1 , the second flue gas treatment mechanism includes a waste heat boiler 6, which can recover part of the waste heat of the flue gas.

[0080] Further, as Figure 1 , a second dust collector 5 is connected to the flue gas inlet side of the waste heat boiler 6. By pre-dusting the flue gas through this second dust collector 5, the dust content of the flue gas entering the waste heat boiler 6 can be significantly reduced, reducing the ash load of the waste heat boiler 6; for converter gas, this second dust collector 5 can also effectively remove the kindling carried in the gas, further improving the safety of the system. The second dust collector 5 includes, but is not limited to, an inertial dust collector, and preferably a cyclone dust collector, which has good dust removal effect and efficiency.

[0081] Among them, the above-mentioned second dust collector 5 can be configured with cooling measures. For example, the dust collector uses a water-cooled wall, which can not only improve the service life of the dust collector, but also cool the flue gas and reduce the ash viscosity in the flue gas (especially for converter gas), thereby reducing the probability of adhesive ash accumulation in the waste heat boiler 6.

[0082] In one embodiment, as Figure 1 , the second flue gas treatment mechanism further includes an intermediate cooling flue 4, which is connected to the corresponding flue gas outlet section 22. The waste heat boiler 6 is connected downstream of the intermediate cooling flue 4. Specifically, when the second dust collector 5 is provided, the flue gas outlet end of the intermediate cooling flue 4 is connected to the second dust collector 5. When the second dust collector 5 is not provided, the intermediate cooling flue 4 can be directly connected to the waste heat boiler 6 (other facilities can be added between the two as needed).

[0083] The above-mentioned intermediate cooling flue 4 can cool the flue gas, effectively reduce the temperature of the flue gas, and greatly reduce the probability of adhesive ash accumulation in the waste heat boiler 6. At the same time, the setting of the intermediate cooling flue 4 also facilitates the equipment layout of the second flue gas treatment mechanism.

[0084] Preferably, as Figure 1 , the intermediate cooling flue 4 is inclined, and its flue gas inlet is located above its flue gas outlet. The inclined design of the intermediate cooling flue 4 is beneficial to the flow and removal of ash particles inside it; in particular, in the intermediate cooling flue 4, the flue gas flow direction is the same as the ash particle flow direction, and the flue gas flow velocity in the intermediate cooling flue 4 is relatively high. Therefore, the flue gas can carry the ash particles and flow by itself, thus avoiding ash accumulation in the intermediate cooling flue 4.

[0085] Preferably, the inclination angle of the intermediate cooling flue 4 relative to the horizontal plane is 30° to 80°.

[0086] Further preferably, as Figure 1, the intermediate cooling flue 4 includes a first inclined flue section 41 and a second inclined flue section 42. The second inclined flue section 42 is connected to the bottom end of the first inclined flue section 41. The inclination angle of the first inclined flue section 41 with respect to the horizontal plane (hereinafter referred to as the inclination angle) is different from that of the second inclined flue section 42 with respect to the horizontal plane; more specifically, the inclination angle of the first inclined flue section 41 is greater than that of the second inclined flue section 42. Based on this design, the large inclination angle design of the first inclined flue section 41 is beneficial to driving dust by flue gas; the design of two-stage flue sections with different inclination angles can increase the flue gas turbulence to a certain extent, thereby improving the heat exchange effect between the gas and the flue wall. Moreover, the two-stage flue design can reduce the concentration of flue thermal stress, extend the service life of the flue, and enable the flue to more flexibly adapt to complex spaces, which is conducive to the layout of waste heat recovery equipment. In one embodiment, the inclination angle of the first inclined flue section 41 is 50° - 80°, and the inclination angle of the second inclined flue section 42 is 30° - 60°

[0087] In the above system, through the vaporization cooling flue 1 + the intermediate cooling flue 4 + (the water-cooled second dust collector 5) + the waste heat boiler 6, the wide-range waste heat recovery of the flue gas can be realized, greatly avoiding the waste of the sensible heat of the flue gas.

[0088] For the treatment of converter gas, preferably, the outlet gas temperature of the vaporization cooling flue 1 is reduced to 800 - 900 °C. Further, the outlet gas temperature of the vaporization cooling flue 1 is controlled at about 850 °C. Preferably, the intermediate cooling flue 4 adopts a vaporization cooling flue. Preferably, the outlet gas temperature of the intermediate cooling flue 4 is reduced to 500 - 700 °C.

[0089] Preferably, explosion relief valves are installed at parts such as the three-way flue 2 and the waste heat boiler 6. In case of gas explosion, the explosion can be vented in time and effectively to ensure the safety of personnel and equipment.

[0090] For the treatment of converter gas, in one embodiment, an additive adding mechanism is provided on the intermediate cooling flue 4 or the second dust collector 5 for adding an additive to the converter gas. The additive added is a substance that can reduce the viscosity of the dust in the gas, including but not limited to kaolin or quartz sand. Kaolin, quartz sand, etc. belong to high melting point substances and are in a solid particle state at the waste heat recovery temperature. After being mixed with converter ash, the overall ash melting point can be increased, thereby reducing the ash viscosity. By the above method, the situation of sticky ash accumulation in the subsequent waste heat boiler 6 can be greatly alleviated, and the reliability of the system operation can be improved. Among them, it is preferably to set the additive adding mechanism on the intermediate cooling flue 4, which is beneficial to the full reaction of the additive with the gas, especially conducive to the removal of the ash particles after the reaction in the second dust collector 5, and reducing the ash load of the waste heat boiler 6. When adding the above additive in the form of powder spraying, better reaction effect and efficiency can be achieved. Therefore, the above additive adding mechanism can include a powder spraying gun arranged on the intermediate cooling flue 4 / second dust collector 5, and the powder spraying gun is configured with a powder bin and a pressure medium supply mechanism. The pressure medium preferably uses inert gases such as nitrogen.

[0091] Preferably, soot blowing devices are provided at positions such as the intermediate cooling flue 4 and the waste heat boiler 6 to regularly clean the heating surface to ensure that the heating surface is clean and unobstructed; the soot blowing method can adopt one or a combination of soot blowing methods such as nitrogen shock wave, acetylene shock wave, high-efficiency sound wave, and steam soot blowing.

[0092] Embodiment Five

[0093] This embodiment provides a waste heat boiler 6, wherein the waste heat boiler 6 can be used in the above-mentioned Embodiment Four.

[0094] Such as Figure 2 , the waste heat boiler 6 includes a first-pass boiler 61, a second-pass boiler 62, and a settling chamber 63. The first-pass boiler 61 and the second-pass boiler 62 are both erected on the settling chamber 63 and are both communicated with the inner cavity of the settling chamber 63. A flue gas inlet is provided at the top of the first-pass boiler 61, and a flue gas outlet is provided at the top of the second-pass boiler 62.

[0095] It can be seen that the above waste heat boiler 6 adopts a double-pass structure design. Flue gas is introduced from the flue gas inlet at the top of the first-pass boiler 61. After the flue gas exchanges heat with the heating surface in the first-pass boiler 61, it enters the settling chamber 63 from the first-pass boiler 61, and then enters the second-pass boiler 62. After exchanging heat with the heating surface in the second-pass boiler 62, it is discharged from the flue gas outlet at the top of the second-pass boiler 62. Among them, the flue gas runs from top to bottom in the first-pass boiler 61 and from bottom to top in the second-pass boiler 62.

[0096] Preferably, in the first return boiler 61, the heating surface 611 is longitudinally scoured, that is, the flue gas longitudinally scours its heating surface. While recovering the waste heat of the flue gas, the degree of ash accumulation can be effectively alleviated and the occurrence of ash accumulation can be reduced.

[0097] In one embodiment, as Figure 2 and Figure 3 , the longitudinally scoured heating surface 611 includes a plurality of longitudinal evaporation tubes 6111. The axes of the longitudinal evaporation tubes 6111 are parallel to the vertical direction. Both ends of the longitudinal evaporation tubes 6111 are respectively connected with bridge connecting tubes 6112, and the bridge connecting tubes 6112 extend outside the furnace shell to connect corresponding medium tubes.

[0098] Preferably, the medium flow direction in the longitudinal evaporation tubes 6111 is from bottom to top, so as to be opposite to the flue gas flow direction in the first return boiler 61, which can improve the heat exchange effect; the bridge connecting tube 6112 at the bottom end of the longitudinal evaporation tube 6111 is used to connect the water inlet pipe, and the bridge connecting tube 6112 at the top end of the longitudinal evaporation tube 6111 is used to connect the water return pipe.

[0099] Preferably, at least part of the bridge connecting tubes 6112 at the top ends of the longitudinal evaporation tubes 6111 are connected to the same distribution header 6113, and at least part of the bridge connecting tubes 6112 at the bottom ends of the longitudinal evaporation tubes 6111 are connected to the same distribution header 6113. This is convenient for centralized management of water inlet and return water, and can also reduce the number of on-site pipelines and simplify the layout.

[0100] Preferably, as Figure 3 , the longitudinal evaporation tubes 6111 are distributed to form a plurality of evaporation tube groups; in each evaporation tube group, the longitudinal evaporation tubes 6111 are distributed in the same vertical plane and are arranged in sequence from the inner wall of the furnace shell to the furnace shell axis direction. And, from the inner wall of the furnace shell to the furnace shell axis direction, the top positions of the longitudinal evaporation tubes 6111 gradually increase, and the bottom positions of the longitudinal evaporation tubes 6111 gradually decrease. This method is convenient for the arrangement of the longitudinal evaporation tubes 6111, can arrange as many longitudinal evaporation tubes 6111 as possible, so as to ensure the heat exchange effect with the flue gas; it can be understood that the closer to the center of the furnace shell, the longer the heat exchange stroke of the longitudinal evaporation tubes 6111, which can also better match the flue gas flow field in the first return boiler 61 and correspondingly improve the heat exchange effect with the flue gas. Optionally, the same evaporation tube group shares one water inlet distribution header 6113 and one water return distribution header 6113.

[0101] The longitudinal heat exchange tubes can be smooth tubes or finned tubes.

[0102] Among them, the bridging pipe 6112 can be horizontally arranged (the axis is parallel to the horizontal plane) or inclinedly arranged (the axis is inclined relative to the horizontal plane). When the bridging pipe 6112 is inclinedly arranged, for example, the top end of the longitudinal evaporation pipe 6111 extends obliquely upward to form the top bridging pipe 6112, and the bottom end of the longitudinal evaporation pipe 6111 extends obliquely downward to form the bottom bridging pipe 6112. The flushing of the flue gas is beneficial to alleviating the ash accumulation on the bridging pipe 6112.

[0103] The above-mentioned first-return boiler 61 is preferably a membrane water wall. Under the combined form of longitudinally flushing the heating surface 611 and the water wall, the recovery effect and efficiency of the flue gas waste heat can be guaranteed.

[0104] In one of the embodiments, as Figure 2 , a plurality of stages of convective evaporators 621 are arranged in the second-return boiler 62 in sequence from bottom to top. Among them, preferably, the flue gas transversely flushes the heating surface of the convective evaporator 621. Specifically, the convective evaporator 621 includes a plurality of horizontal evaporation pipes, and the axes of the horizontal evaporation pipes are preferably parallel to the horizontal plane.

[0105] When used for gas treatment in the above-mentioned fourth embodiment, after the previous multi-stage cooling, the temperature of the gas entering the second-return boiler 62 is relatively low. The ash accumulation formed in the second-return boiler 62 is mainly loose ash, and the removal difficulty is relatively low; while the use of horizontal evaporation pipes can improve the heat exchange effect and efficiency with the gas. Even if ash accumulation occurs, it is not easy to have the phenomenon of ash blockage. Preferably, the gas temperature at the outlet side of the first-return boiler 61 is below the cohesive ash temperature (defined as the gas temperature at which cohesive ash is easily formed), which can ensure the normal operation of the second-return boiler 62. Specifically, the gas temperature at the outlet side of the first-return boiler 61 is reduced to 400-600°C.

[0106] Among them, the horizontal evaporation pipe can be a smooth pipe or a finned pipe.

[0107] Among them, a plurality of horizontal evaporation pipes can be arranged on the cross-section of the convective evaporator 621; the vertical arrangement mode of the horizontal evaporation pipes can be in-line arrangement, staggered arrangement or a combination of the two arrangement modes, etc.

[0108] Among them, the convective evaporators 621 at all levels can be in series (the inlet water runs from the convective evaporator 621 at the topmost to the convective evaporator 621 at the lower level in sequence), or in parallel (the inlet and outlet water of each convective evaporator 621 are independent of each other), or some of the convective evaporators 621 are in series.

[0109] Further preferably, as Figure 2In the second return boiler 62, at least one economizer 622 is arranged downstream of the last-stage convection evaporator 621. When there are multiple economizers 622, the economizers 622 are arranged in sequence from bottom to top.

[0110] Preferably, the flue gas flushes the heating surface of the economizer 622 laterally.

[0111] Optionally, the economizer 622 includes a plurality of serpentine evaporator tubes, which are arranged in a serpentine shape on the cross section of the economizer 622; the vertical arrangement of each serpentine evaporator tube may be in-line arrangement, staggered arrangement or a combination of the two arrangements.

[0112] The serpentine evaporation tube can be a plain tube or a finned tube.

[0113] Preferably, multiple soot blowers are arranged in the first return boiler 61 and the second return boiler 62 to clean the heating surface regularly to ensure that the heating surface is clean and unobstructed; the cleaning method can be one or a combination of nitrogen shock wave, acetylene shock wave, high-efficiency sound wave, steam soot blowing, etc. Further, detectors are arranged in the first return boiler 61 and the second return boiler 62. The detectors can be carbon monoxide concentration detectors and / or oxygen concentration detectors. The detectors are preferably interlocked with the soot blowers to achieve automatic control of soot blowing.

[0114] Optionally, both the first return boiler 61 and the second return boiler 62 are provided with inspection manholes.

[0115] The first return boiler 61 and the settling chamber 63, and the second return boiler 62 and the settling chamber 63 can be fixed by welding, flange fixing, or integral molding. The settling chamber 63 can play the role of inertial dust removal, further reducing the probability of dust accumulation and blockage of the waste heat boiler 6; in addition, the dust falling from the first return boiler 61 and the second return boiler 62 will enter the settling chamber 63, which is conducive to dust recovery.

[0116] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A three-way flue with a blind plate switching function, comprising a flue gas inlet section and two flue gas outlet sections, characterized in that: Both smoke outlet sections are provided with a gate valve, and the two groups of gate valves share a group of gate components, the gate component includes a blind plate and a orifice plate, wherein the orifice plate is a gate plate with a through hole, the blind plate is selectively inserted in one of the valve seats, and the orifice plate is inserted in the other valve seat; the three-way flue is provided with a blind plate switching actuator for exchanging the blind plate with the orifice plate.

2. The three-way flue according to claim 1, characterized in that: Define the valve seats of the two gate valves as a first valve seat and a second valve seat respectively; The blind plate switching actuator includes an annular switching track and two sets of lifting devices movably arranged on the annular switching track, wherein the annular switching track includes a first regular track section located directly above the first valve seat, a second regular track section located directly above the second valve seat, and a transfer track section connecting the first regular track section and the second regular track section, the guide direction of the first regular track section is perpendicular to the axial direction of the first valve seat, and the guide direction of the second regular track section is perpendicular to the axial direction of the second valve seat.

3. The three-way flue according to claim 2, characterized in that: The transfer track segment includes two first extension track segments, two second extension track segments and two relay track segments, wherein: The two first extension track segments are respectively connected to two ends of the first main track segment, and the guiding directions of the two first extension track segments are parallel to the guiding direction of the first main track segment; The two second extended track segments are respectively connected to two ends of the second main track segment, and the guiding directions of the two second extended track segments are parallel to the guiding direction of the second main track segment; The first extended track segment and the second extended track segment on the same side are connected by a relay track segment.

4. The three-way flue as claimed in claim 3, characterized in that: The sum of the lengths of the first normal track section and the two first extended track sections L1≥3D, where D is the outer edge diameter of the blind plate.

5. The three-way flue as claimed in claim 3, characterized in that: The sum of the lengths of the second regular track section and the two second extended track sections L2≥3D, where D is the outer edge diameter of the blind plate.

6. The three-way flue as claimed in claim 2, characterized in that: The lifting device adopts a lifting hoist.

7. The three-way flue as claimed in claim 2, characterized in that: The annular switching track is installed on the flue through a bracket, or installed on a foundation or equipment around the flue.

8. The three-way flue according to claim 1, characterized in that: The blind plate and the orifice plate are both water-cooled gate plates.

9. The three-way flue according to claim 1, characterized in that: The smoke inlet section and the two smoke outlet sections are both in the form of vaporization cooling flues.

10. A flue gas treatment system, comprising a vaporization cooling flue, characterized in that: It is also provided with a three-way flue as described in any one of claims 1 to 9, wherein the flue gas inlet section is connected to the vaporization cooling flue, and the two flue gas outlet sections are respectively connected to flue gas treatment mechanisms.

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