Three-way flue for waste heat recovery and flue gas waste heat recovery system

Abstract

The utility model relates to a three-way flue for waste heat recovery and a flue gas waste heat recovery system provided with the three-way flue, the three-way flue comprises a flue gas inlet section and two flue gas outlet sections, and the flue gas inlet section and the two flue gas outlet sections all adopt an evaporative cooling flue form; part of the evaporative cooling pipeline of the flue gas inlet section is coupled with at least part of the evaporative cooling pipeline of one flue gas outlet section to form a first heating surface, and the other evaporative cooling pipeline of the flue gas inlet section is coupled with at least part of the evaporative cooling pipeline of the other flue gas outlet section to form a second heating surface. According to the utility model, the three-way flue adopts an evaporative cooling flue form, so that the three-way flue has a waste heat recovery function; moreover, through the coupling between the flue gas inlet section and the flue gas outlet section, a reasonable heating surface is designed, the evaporative cooling effect and the heating uniformity of each part of the three-way flue are ensured, the number of steam-water pipelines can be reduced, and field implementation is facilitated.

Description

Technical Field

[0001] This utility model belongs to the field of flue gas waste heat recovery and utilization, specifically relating to a three-way flue for waste heat recovery and a flue gas waste heat recovery system equipped with the three-way flue. Background Technology

[0002] In waste heat recovery systems, three-way flues are a common duct configuration used to split or combine flue gas to adapt to different process requirements, achieving effects such as optimizing flue gas flow and improving heat recovery efficiency. These three-way flues are generally insulated flues, and their main applications include:

[0003] (1) Parallel connection of multiple waste heat boilers: the flue gas is diverted to multiple boilers to improve the system's processing capacity;

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

[0005] (3) Flue gas mixing: Flue gas at different temperatures is mixed and adjusted to a suitable temperature before entering the heat recovery equipment.

[0006] It is evident that although the current three-way flue is widely used in waste heat recovery systems, it does not yet have waste heat recovery function, which limits its application scope to a certain extent. Utility Model Content

[0007] This utility model relates to a three-way flue for waste heat recovery and a flue gas waste heat recovery system equipped with the three-way flue, which can at least solve some of the defects of the prior art.

[0008] This utility model relates to a three-way flue for waste heat recovery, including a flue gas inlet section and two flue gas outlet sections, wherein the flue gas inlet section and the two flue gas outlet sections are both in the form of vaporization cooling flue.

[0009] A portion of the vaporization cooling pipe in the flue gas inlet section is coupled with at least a portion of the vaporization cooling pipe in one of the flue gas outlet sections to form a first heating surface, and the remaining vaporization cooling pipe in the flue gas inlet section is coupled with at least a portion of the vaporization cooling pipe in the other flue gas outlet section to form a second heating surface.

[0010] As one implementation method, a portion of the vaporization cooling pipes in the flue gas inlet section are coupled with all the vaporization cooling pipes in one of the flue gas outlet sections to form the first heating surface, and the remaining vaporization cooling pipes in the flue gas inlet section are coupled with all the vaporization cooling pipes in the other flue gas outlet section to form the second heating surface.

[0011] As one implementation method, the vaporization cooling pipe in the flue gas inlet section is defined as the first cooling pipe, and the vaporization cooling pipe in the flue gas outlet section is defined as the second cooling pipe; each first cooling pipe is coupled with multiple second cooling pipes.

[0012] As one implementation method, when each first cooling pipe is coupled to two second cooling pipes, a Y-shaped trouser tube is used to complete the coupling. The two legs of the Y-shaped trouser tube are respectively connected to the two second cooling pipes, and the other end of the Y-shaped trouser tube is connected to the first cooling pipe.

[0013] As one implementation method, a portion of the vaporization cooling pipe in the flue gas inlet section is coupled with the lower half of one of the flue gas outlet sections to form the first heating surface, the remaining vaporization cooling pipe in the flue gas inlet section is coupled with the lower half of the other flue gas outlet section to form the second heating surface, and the upper halves of the two flue gas outlet sections are coupled to form the third heating surface.

[0014] As one embodiment, the first heating surface is provided with one or more inlet water headers and an equal number of return water headers.

[0015] As one embodiment, the second heating surface is provided with one or more inlet water headers and an equal number of return water headers.

[0016] As one implementation method, water-cooled valves are provided on both of the flue gas outlet sections.

[0017] This utility model also provides a flue gas waste heat recovery system, including a vaporization cooling flue and a three-way flue for waste heat recovery 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 to a flue gas treatment mechanism.

[0018] This utility model has at least the following beneficial effects:

[0019] In this invention, the three-way flue adopts the form of a vaporization cooling flue, thus having the function of waste heat recovery; moreover, by coupling the flue gas inlet section and the flue gas outlet section, a reasonable heat-receiving surface is designed to ensure the vaporization cooling effect and heat uniformity of the three-way flue, which can reduce the number of steam and water pipes and facilitate on-site implementation. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the converter gas recovery system provided in an embodiment of the present invention;

[0022] Figure 2A schematic diagram of the waste heat boiler provided in an embodiment of this utility model;

[0023] Figure 3 A schematic diagram of the structure of the first-pass boiler provided in this embodiment of the utility model;

[0024] Figure 4 This is a schematic diagram of the structure of a three-way flue provided in an embodiment of the present utility model;

[0025] Figure 5 This is a schematic diagram of the structure of the annular switching track provided in an embodiment of the present utility model;

[0026] Figure 6 and Figure 7 A schematic diagram of the structure of the water-cooled blind plate provided in an embodiment of this utility model;

[0027] Figure 8 A schematic diagram of the structure of the water-cooled blind plate body;

[0028] Figure 9 This is a schematic diagram of the structure of the water-cooled perforated plate provided in an embodiment of the present invention. Detailed Implementation

[0029] The technical solutions in the embodiments of this utility model are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0030] Example 1

[0031] like Figure 4 This utility model embodiment provides a three-way flue 2 for waste heat recovery, including a flue gas inlet section 21 and two flue gas outlet sections 22. The flue gas inlet section 21 and the two flue gas outlet sections 22 are both in the form of vaporization cooling flue, that is, the flue gas inlet section 21 and the flue gas outlet sections 22 are formed by multiple vaporization cooling pipes surrounding each other to form a corresponding flue.

[0032] Furthermore, a portion of the vaporization cooling pipe of the flue gas inlet section 21 is coupled with at least a portion of the vaporization cooling pipe of one of the flue gas outlet sections 22 to form a first heating surface, and the remaining vaporization cooling pipe of the flue gas inlet section 21 is coupled with at least a portion of the vaporization cooling pipe of the other flue gas outlet section 22 to form a second heating surface.

[0033] In one embodiment, a portion of the vaporization cooling pipes of the flue gas inlet section 21 is coupled with all the vaporization cooling pipes of one of the flue gas outlet sections 22 to form the first heating surface, and the remaining vaporization cooling pipes of the flue gas inlet section 21 are coupled with all the vaporization cooling pipes of the other flue gas outlet section 22 to form the second heating surface; for example, the left half of the flue gas inlet section 21 is coupled with the entire flue gas outlet section 22 on its left to form the first heating surface, and the right half of the flue gas inlet section 21 is coupled with the entire flue gas outlet section 22 on its right to form the second heating surface.

[0034] In this embodiment, the three-way flue 2 adopts the form of vaporization cooling flue 1, thus having the function of waste heat recovery; moreover, through the coupling between the flue gas inlet section 21 and the flue gas outlet section 22, a reasonable heat receiving surface is designed to ensure the vaporization cooling effect and heat uniformity at all parts of the three-way flue 2, which can reduce the number of steam and water pipes and facilitate on-site implementation.

[0035] For ease of description, the vaporization cooling pipe of flue gas inlet section 21 is defined as the first cooling pipe 211, and the vaporization cooling pipe of flue gas outlet section 22 is defined as the second cooling pipe 221.

[0036] The coupling between vaporization cooling pipes is to connect the vaporization cooling pipes to form a water channel. 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 sequence for heat exchange, and then exits from the second vaporization cooling pipe to form cooling return water.

[0037] More preferably, each first cooling pipe 211 is coupled with multiple second cooling pipes 221, including but not limited to one first cooling pipe 211 coupled with two second cooling pipes 221. For the structure of one first cooling pipe 211 coupled with two second cooling pipes 221, preferably, as shown... Figure 4 A Y-shaped cooling pipe 23 is used for coupling. The two ends of the Y-shaped cooling pipe 23 are connected to two second cooling pipes 221, and the other end is connected to the first cooling pipe 211. Based on this structure, reliable coupling between the flue gas inlet section 21 and the flue gas outlet section 22 can be achieved, a reasonable heat-receiving surface can be designed, and the vaporization cooling effect and heat uniformity at all points of the three-way flue 2 can be guaranteed.

[0038] Among them, flat steel partitions or the like can be used to seal the adjacent Y-shaped trouser tubes 23.

[0039] In another embodiment, the heating surface can be configured as follows: a portion of the vaporization cooling pipe of the flue gas inlet section 21 is coupled with the lower half of one of the flue gas outlet sections 22 to form a first heating surface; the remaining vaporization cooling pipe of the flue gas inlet section 21 is coupled with the lower half of the other flue gas outlet section 22 to form a second heating surface; and the upper halves of the two flue gas outlet sections 22 are coupled to form a third heating surface.

[0040] Preferably, the first heating surface is equipped with one or more inlet water headers and one or more return water headers. More preferably, the number of inlet water headers and return water headers are the same and they are configured in a one-to-one correspondence. For example, in a 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, the first cooling pipes 211 in the upper half can share one inlet water header, and the second cooling pipes 221 can share one return water header; similarly, the first cooling pipes 211 in the lower half can share one inlet water header, and the second cooling pipes 221 can share one return water header. Furthermore, the two inlet water headers are connected to the same inlet water pipe, and the two return water headers are connected to the same return water pipe. The second heating surface can adopt the same inlet and return water configuration.

[0041] Preferably, both of the flue gas outlet sections 22 are equipped with water-cooled valves 3.

[0042] Example 2

[0043] like Figure 1 This utility model provides a flue gas waste heat recovery system, including a vaporization cooling flue 1 and a three-way flue 2 for waste heat recovery provided in the first embodiment above. The flue gas inlet section 21 is connected to the vaporization cooling flue 1, and the two flue gas outlet sections 22 are respectively connected to a flue gas treatment mechanism.

[0044] Preferably, both flue gas outlet sections 22 are equipped with water-cooled valves 3, allowing flue gas to selectively enter one of the flue gas treatment mechanisms for processing. This provides high process flexibility, ensures the treatment effect of the flue gas, and improves the reliability and safety of the flue gas treatment. The two flue gas treatment mechanisms can serve as backups for each other. When one mechanism is out of service, the other mechanism can be switched to perform treatment, thus facilitating the inspection and maintenance of the flue gas treatment mechanisms.

[0045] In one embodiment, the flue gas waste heat recovery system is used for the treatment of converter gas, and the vaporization cooling flue 1 is connected to the converter.

[0046] The two flue gas treatment mechanisms are defined as the first flue gas treatment mechanism and the second flue gas treatment mechanism.

[0047] Optionally, such as Figure 1The first flue gas treatment mechanism includes an evaporative cooler 7, the flue gas inlet of which is connected to one of the flue gas inlet sections 21. Further, a first dust collector is connected to the flue gas outlet side of the evaporative cooler 7, and this first dust collector is connected to downstream equipment; the first dust collector includes, but is not limited to, an inertial dust collector.

[0048] In one embodiment, such as Figure 1 The second flue gas treatment unit includes a waste heat boiler 6, which can recover part of the waste heat from the flue gas.

[0049] Furthermore, such as Figure 1 A second dust collector 5 is connected to the flue gas inlet side of the waste heat boiler 6. This second dust collector 5 pre-removes dust from the flue gas, significantly reducing the dust content of the flue gas entering the waste heat boiler 6 and alleviating its ash load. For converter gas, the second dust collector 5 can also effectively remove any ignition sources carried in the gas, further improving system safety. This second dust collector 5 includes, but is not limited to, inertial dust collectors, but preferably cyclone dust collectors, which have good dust removal effect and efficiency.

[0050] The second dust collector 5 can be equipped with cooling measures, such as water-cooled walls, which can improve the service life of the dust collector, cool the flue gas, and reduce the stickiness of ash in the flue gas (especially for converter gas), thereby reducing the probability of sticky ash accumulation in the waste heat boiler 6.

[0051] In one embodiment, such as Figure 1 The second flue gas treatment mechanism also 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 a 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).

[0052] The aforementioned intermediate cooling flue duct 4 can cool the flue gas, effectively reducing its temperature and significantly decreasing the likelihood of sticky ash buildup in the waste heat boiler 6. Simultaneously, the intermediate cooling flue duct 4 facilitates the equipment layout of the second flue gas treatment unit.

[0053] Preferably, such as Figure 1 The intermediate cooling flue 4 is arranged at an angle, and its flue gas inlet is located above its flue gas outlet. The angled design of the intermediate cooling flue 4 is conducive 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 velocity in the intermediate cooling flue 4 is relatively high. Therefore, the flue gas can carry the ash particles and flow by itself, thereby avoiding ash accumulation in the intermediate cooling flue 4.

[0054] Preferably, the intermediate cooling flue 4 has an inclination angle of 30° to 80° relative to the horizontal plane.

[0055] More preferably, such 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 relative to the horizontal plane (hereinafter referred to as the inclination angle) is different from that of the second inclined flue section 42 relative 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 of the first inclined flue section 41 is beneficial for driving away dust through flue gas; the two-section flue section design with different inclination angles increases flue gas turbulence to a certain extent, thereby improving the heat exchange effect between the gas and the flue wall. Moreover, the two-section flue design can reduce the phenomenon of thermal stress concentration in the flue, extend the service life of the flue, and make the flue more flexible to adapt to complex spaces, which is conducive to the arrangement of waste heat recovery equipment. In one embodiment, the inclination angle of the first inclined flue section 41 is 50° to 80°, and the inclination angle of the second inclined flue section 42 is 30° to 60°.

[0056] In the above system, the waste heat recovery of flue gas over a wide area can be achieved through the first cooling flue + intermediate cooling flue 4 + (water-cooled second dust collector 5) + waste heat boiler 6, which greatly avoids the waste of sensible heat of flue gas.

[0057] For the treatment of converter gas, preferably, the outlet gas temperature of the vaporization cooling flue 1 is reduced to 800-900°C, and further preferably, the outlet gas temperature of the vaporization cooling flue 1 is controlled at around 850°C. Preferably, the intermediate cooling flue 4 adopts the vaporization cooling flue 1. Preferably, the outlet gas temperature of the intermediate cooling flue 4 is reduced to 500-700°C.

[0058] Preferably, explosion relief valves are installed at locations such as the three-way flue 2 and the waste heat boiler 6, so that in the event of a gas explosion, the explosion can be relieved in a timely and effective manner, ensuring the safety of personnel and equipment.

[0059] In one embodiment, for the treatment of converter gas, an additive addition mechanism is provided on the intermediate cooling flue 4 or the second dust collector 5 to add additives to the converter gas. The added additives are substances that can reduce the stickiness of dust in the gas, including but not limited to kaolin or quartz sand. Kaolin and quartz sand are high-melting-point substances, existing as solid particles at the waste heat recovery temperature. When mixed with converter ash, they can increase the overall ash melting point, thereby reducing ash stickiness. This method can greatly alleviate the sticky ash accumulation in the subsequent waste heat boiler 6, improving the reliability of system operation. Preferably, the additive addition mechanism is provided on the intermediate cooling flue 4, which facilitates the full reaction of the additives with the gas, particularly facilitating the removal of the reacted ash particles in the second dust collector 5, reducing the ash load on the waste heat boiler 6. When the above-mentioned admixtures are added by spraying, a better reaction effect and efficiency can be achieved. Therefore, the admixture addition mechanism may include a powder spraying gun installed on the intermediate cooling flue 4 / second dust collector 5. The powder spraying gun is equipped with a powder hopper and a pressure medium supply mechanism. The pressure medium is preferably an inert gas such as nitrogen.

[0060] Optionally, the water-cooled valve 3 mentioned above is a slide gate valve, including but not limited to a blind valve.

[0061] Preferably, a ash removal device is installed in the intermediate cooling flue 4, waste heat boiler 6 and other parts to regularly remove ash from the heating surface to ensure that the heating surface is clean and unobstructed; the ash removal method can be one or a combination of nitrogen shock wave, acetylene shock wave, high-efficiency sonic wave, steam soot blowing and other ash removal methods.

[0062] Example 3

[0063] This utility model embodiment provides a waste heat boiler 6, which can be used in the above embodiment two.

[0064] like 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 connected to the inner cavity of the settling chamber 63. The top of the first pass boiler 61 is provided with a flue gas inlet, and the top of the second pass boiler 62 is provided with a flue gas outlet.

[0065] As can be seen, the aforementioned 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 exchanging heat with the heating surfaces inside the first-pass boiler 61, the flue gas 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 surfaces inside the second-pass boiler 62, the flue gas is discharged from the flue gas outlet at the top of the second-pass boiler 62. The flue gas flows from top to bottom in the first-pass boiler 61 and from bottom to top in the second-pass boiler 62.

[0066] Preferably, in the first pass boiler 61, the heating surface 611 is longitudinally flushed, that is, the flue gas longitudinally flushes its heating surface, which can effectively alleviate the degree of ash accumulation and reduce the occurrence of ash accumulation while recovering the waste heat of the flue gas.

[0067] In one embodiment, such as Figure 3 The longitudinal scouring heating surface 611 includes multiple longitudinal evaporation tubes 6111. The axis of the longitudinal evaporation tubes 6111 is parallel to the vertical direction. Both ends of the longitudinal evaporation tubes 6111 are respectively connected to bridging pipes 6112. The bridging pipes 6112 extend to the outside of the furnace shell to connect to the corresponding medium pipes.

[0068] Preferably, the medium flow direction in the longitudinal evaporator 6111 is from bottom to top, which is opposite to the flue gas flow direction in the first return boiler 61, thus improving the heat exchange effect; the bridge pipe 6112 at the bottom of the longitudinal evaporator 6111 is used to connect the inlet pipe, and the bridge pipe 6112 at the top of the longitudinal evaporator 6111 is used to connect the return pipe.

[0069] Preferably, at least a portion of the bridging pipe 6112 at the top of the longitudinal evaporator pipe 6111 is connected to the same distribution manifold 6113, and at least a portion of the bridging pipe 6112 at the bottom of the longitudinal evaporator pipe 6111 is connected to the same distribution manifold 6113. This facilitates centralized management of water inlet and outlet, and also reduces the number of on-site pipes and simplifies the layout.

[0070] Preferably, such as Figure 3 The longitudinal evaporator tubes 6111 are distributed to form multiple evaporator tube groups. Within each evaporator tube group, the longitudinal evaporator tubes 6111 are distributed in the same vertical plane and arranged sequentially from the inner wall of the furnace shell towards the furnace shell axis. Furthermore, from the inner wall of the furnace shell towards the furnace shell axis, the top position of each longitudinal evaporator tube 6111 gradually increases, and the bottom position of each longitudinal evaporator tube 6111 gradually decreases. This arrangement facilitates the arrangement of the longitudinal evaporator tubes 6111, allowing for the placement of as many longitudinal evaporator tubes 6111 as possible, thereby ensuring effective heat exchange with the flue gas. Understandably, the closer to the center of the furnace shell, the longer the heat exchange path of the longitudinal evaporator tubes 6111, which also better matches the flue gas flow field within the first pass boiler 61, correspondingly improving the heat exchange effect with the flue gas. Optionally, the same evaporator tube group shares a single inlet water distribution manifold 6113 and a return water distribution manifold 6113.

[0071] The longitudinal heat exchange tube can be a bare tube or a finned tube.

[0072] The bridging pipe 6112 can be arranged horizontally (with its axis parallel to the horizontal plane) or inclined (with its axis inclined relative to the horizontal plane). When the bridging pipe 6112 is arranged inclined, for example, the top end of the longitudinal evaporator pipe 6111 extends obliquely upward to form the top bridging pipe 6112 and the bottom end of the longitudinal evaporator pipe 6111 extends obliquely downward to form the bottom bridging pipe 6112, the flushing effect of the flue gas helps to alleviate the accumulation of ash on the bridging pipe 6112.

[0073] The aforementioned first-pass boiler 61 preferably adopts a membrane water-cooled wall. With the combination of the longitudinally scouring heating surface 611 and the water-cooled wall, the recovery effect and efficiency of the flue gas waste heat can be guaranteed.

[0074] In one embodiment, such as Figure 2 The second-pass boiler 62 has multiple stages of convective evaporators 621 arranged sequentially from bottom to top. Preferably, the flue gas scours the heating surface of the convective evaporator 621 laterally. Specifically, the convective evaporator 621 includes multiple transverse evaporation tubes, and the axis of the transverse evaporation tubes is preferably parallel to the horizontal plane.

[0075] When used for gas treatment in Embodiment 2 above, after the preceding multi-stage cooling, the gas temperature entering the second pass boiler 62 is relatively low. The ash accumulated in the second pass boiler 62 is mainly loose ash, which is relatively easy to remove. Furthermore, using horizontal evaporator tubes can improve the heat exchange effect and efficiency with the gas, and even if ash accumulates, ash blockage is less likely to occur. Preferably, the gas temperature at the outlet side of the first pass boiler 61 is below the temperature of sticky ash (defined as the temperature of gas that easily forms sticky ash), which can ensure the normal operation of the second pass boiler 62. Specifically, the gas temperature at the outlet side of the first pass boiler 61 is reduced to 400–600°C.

[0076] The horizontal evaporator tube can be either a bare tube or a finned tube.

[0077] Among them, multiple horizontal evaporation tubes can be arranged on the cross-section of the convection evaporator 621; the vertical arrangement of the horizontal evaporation tubes can be in a straight line, staggered, or a combination of the two arrangements.

[0078] The convection evaporators 621 at each stage can be connected in series (the water inlet runs from the uppermost convection evaporator 621 to the lower convection evaporators 621 in sequence), or they can be connected in parallel (the water inlet and outlet of each convection evaporator 621 are independent of each other), or some convection evaporators 621 can be connected in series.

[0079] More preferably, such as Figure 2In the second pass boiler 62, at least one economizer 622 is arranged downstream of the final stage convective evaporator 621. When there are multiple economizers 622, they are arranged sequentially from bottom to top.

[0080] Preferably, the flue gas laterally washes over the heating surface of the economizer 622.

[0081] Optionally, the economizer 622 includes multiple serpentine evaporator tubes, which extend in a serpentine pattern across the cross-section of the economizer 622. The vertical arrangement of each serpentine evaporator tube can be in a straight line, staggered, or a combination of both.

[0082] Among them, the serpentine evaporator tube can be a bare tube or a finned tube.

[0083] Preferably, multiple soot blowers are arranged in both the first pass boiler 61 and the second pass boiler 62 to periodically clean the heating surfaces, ensuring that the heating surfaces are clean and unobstructed. The soot cleaning method can be one or a combination of nitrogen shock wave, acetylene shock wave, high-efficiency sonic wave, steam soot blowing, etc. Furthermore, detectors are arranged in both the first pass boiler 61 and the second pass boiler 62. The detectors can be carbon monoxide concentration detectors and / or oxygen concentration detectors. Preferably, the detectors are interlocked with the soot blowers to achieve automatic control of soot blowing.

[0084] Optionally, both the first pass boiler 61 and the second pass boiler 62 are provided with maintenance manholes.

[0085] The first pass boiler 61 and the settling chamber 63, and the second pass boiler 62 and the settling chamber 63, can be fixed by welding, flange, or integral molding. The settling chamber 63 serves as an inertial dust collector, further reducing the likelihood of ash accumulation and blockage in the waste heat boiler 6. Additionally, dust falling from the first pass boiler 61 and the second pass boiler 62 will enter the settling chamber 63, thus facilitating dust recovery.

[0086] Example 4

[0087] This embodiment further optimizes the flue gas waste heat recovery system provided in Embodiment 2 above. Specifically, the two sets of water-cooled valves 3 are further optimized as follows:

[0088] For ease of description, the two sets of water-cooled valves 3 are defined as the first water-cooled valve 3 and the second water-cooled valve 3.

[0089] Both sets of water-cooled valves 3 are plug-in valves, including valve seats, and share a gate assembly. The gate assembly includes a blind plate 30a and an orifice plate 30b, where the orifice plate 30b is a gate with a through hole. The blind plate 30a is selectively inserted into one valve seat, and the orifice plate 30b is inserted into the other valve seat. When the blind plate 30a is inserted into one valve seat, the water-cooled valve 3 is in the closed state, while the other water-cooled valve 3 is in the open state due to the orifice plate 30b at its valve seat. Based on this design, flue gas can only enter one flue gas treatment mechanism, preventing it from entering both mechanisms simultaneously, thus ensuring system reliability and avoiding malfunctions. The use of the blind plate 30a and orifice plate 30b for switching ensures valve sealing.

[0090] When the two mechanisms need to switch operation, the insertion position of the blind plate 30a needs to be switched, that is, the blind plate 30a is switched from the valve seat that is currently in the closed state to the valve seat that is currently in the open state. Accordingly, a blind plate switching actuator is provided.

[0091] like Figure 5 The blind plate switching actuator includes a ring switching track 8 and two sets of lifting devices movably mounted on the ring switching track 8. The ring switching track 8 includes a first main track section 81 located directly above the first water-cooled valve 3, a second main track section 82 located directly above the second water-cooled valve 3, and a transfer track section connecting the first main track section 81 and the second main track section 82. The guiding direction of the first main track section 81 is perpendicular to the flue axis at the first water-cooled valve 3, and the guiding direction of the second main track section 82 is perpendicular to the flue axis at the second water-cooled valve 3.

[0092] The aforementioned lifting device is used to lift the gate plate 30 of one of the water-cooled valves 3, and then move it on the annular switching track 8 to the other water-cooled valve 3 for installation. The annular switching track 8 can ensure the smooth 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 maintenance efficiency and saving maintenance time.

[0093] Preferably, such as Figure 5 The transfer track segment includes two first extension track segments 83, two second extension track segments 84, and two relay track segments 85, among which,

[0094] Two first extension track sections 83 are connected to both ends of the first main track section 81, and the guiding direction of the two first extension track sections 83 is parallel to the guiding direction of the first main track section 81. This improves the smoothness and reliability of replacing the gate at the first water-cooled valve 3.

[0095] Two second extension track sections 84 are connected to both ends of the second main track section 82, and the guiding direction of the two second extension track sections 84 is parallel to the guiding direction of the second main track section 82. This improves the smoothness and reliability of replacing the gate at the second water-cooled valve 3.

[0096] The first extension track segment 83 and the second extension track segment 84 on the same side are connected by a relay track segment 85.

[0097] Preferably, the sum of the lengths of the first main track section 81 and the two first extended track sections 83, L1, is greater than or equal to 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 section 82 and the two second extended track sections 84, L2, is greater than or equal to 3D, to ensure that the blind plate 30a / orifice plate 30b can be smoothly pushed out and pushed in.

[0098] When the first water-cooled valve 3 and the second water-cooled valve 3 are coaxial, it is obvious that the first main rail section 81 and the second main rail section 82 are parallel.

[0099] The aforementioned lifting devices include, but are not limited to, lifting hoists, which can be manual or electric hoists.

[0100] The aforementioned annular switching track 8 can be installed on the three-way flue 2 via a bracket, or it can be installed on the workshop foundation or equipment around the three-way flue 2.

[0101] Example 5

[0102] This embodiment provides a water-cooled blind plate 30a, which can be used in the slide gate valve in Embodiments 2 / 4 above.

[0103] like Figures 6-8 The water-cooled blind plate 30a includes a blind plate body 301, and a water-cooling unit is provided inside the blind plate body 301 to ensure that the blind plate body 301 can withstand high temperature environment.

[0104] Optionally, the water-cooling unit includes, but is not limited to, one or more cooling channels such as spiral cooling water channels and serpentine cooling water channels, and the cooling water inlet manifold and return manifold can be one or more. When the water-cooling unit uses water-cooling pipes, these water-cooling pipes form part of the blind plate body 301; the blind plate body 301 can be constructed solely from these water-cooling pipes to form a circular structure, or the blind plate body 301 can further include other components, such as fixing these water-cooling pipes to the substrate.

[0105] The water inlet and return ends of the water-cooling unit are located outside the outer periphery of the blind plate body 301 to facilitate connection with the water inlet pipe and the water return pipe.

[0106] More preferably, refractory material layers 302 are 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, better 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, multiple expansion joints are formed in the refractory material layer 302. The expansion joints include, but are not limited to, structures formed by embedding refractory aluminosilicate fiber felt or other refractory soft materials in the refractory material. This can improve the thermal expansion performance of the refractory material layer 302, which can better meet the operating conditions of discontinuous generation of flue gas such as converter gas.

[0107] More preferably, anchoring claws are provided on both sides of the blind flange body 301, which can improve the reliability of the connection between the refractory material layer 302 and the blind flange body 301.

[0108] In one embodiment, the outer periphery of the blind flange body 301 is provided with a connecting flange for connection to the valve seat flange.

[0109] Preferably, an annular sealing cavity 304 is formed on the outer periphery 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, a sealing rope.

[0110] In one embodiment, a purging unit 303 is provided at least on the air-facing surface of the blind plate body 301 to protect the air-facing surface through purging, including but not limited to nitrogen purging. 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 embedded 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. The purging main pipe 3031 is constructed as a plurality of annular distribution pipes, and a plurality of short pipe nozzles 3032 are provided 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 may also be branched, with a plurality of short pipe nozzles 3032 provided on each branch.

[0111] The air intake end of the purge main pipe 3031 extends beyond the outer periphery of the blind plate body 301 to facilitate connection with the relevant air source.

[0112] More preferably, such as Figure 6 The blowing direction of the short pipe nozzle 3032 is inclined relative to the axis of the blind plate body 301. This method can improve the protective blowing effect and reduce the chance of the short pipe nozzle 3032 getting clogged. More preferably, the blowing direction of the short pipe nozzle 3032 is oriented toward the axis of the blind plate body 301.

[0113] The aforementioned purge main pipe 3031 is preferably fixedly connected to the blind plate body 301. Understandably, the purge main pipe 3031, especially the short pipe nozzles 3032, can act as anchors, effectively improving the reliability of the connection 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 purge units 303.

[0114] In one embodiment, the refractory material on the air-facing surface of the blind flange body 301 is a breathable refractory material. For example, the refractory material layer 302 on the air-facing surface includes a first refractory layer and a second refractory layer located outside the first refractory layer. The second refractory layer is made of a breathable refractory material, and the air permeability of the first refractory layer is lower than that of the second refractory layer. The aforementioned purge pipe 3031 can be arranged in the first refractory layer or in the second refractory layer. Multiple air outlets can be provided on the purge pipe 3031 facing the second refractory layer for supplying air to the second refractory layer; or, a separate air supply pipe can be provided to supply air to the second refractory layer. Based on the above scheme, under the action of the gas permeating the second refractory layer, the dust on the air-facing surface can be blown away or peeled off, thereby improving the protective purging effect. In addition, by supplying gas to the second refractory layer, it can also cool the refractory material layer 302, better protect the water-cooled blind plate 30a, and supply cooling gas (preferably an inert gas, such as low-temperature nitrogen) to the second refractory layer under specific working conditions / abnormal working conditions that may generate high-temperature / ultra-high-temperature flue gas.

[0115] Optionally, such as Figure 9 Based on 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 to form through holes according to a set diameter, and a water-cooled perforated plate 30b can be obtained. The water-cooled perforated plate 30b can be used in the above-mentioned embodiment four; wherein, preferably, the diameter of the through hole is smaller than the diameter of the blind plate body 301 and the refractory material layer 302.

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

Claims

1. A three-way flue for waste heat recovery, characterized in that, It includes a flue gas inlet section and two flue gas outlet sections, both of which adopt the form of vaporization cooling flue. A portion of the vaporization cooling pipe in the flue gas inlet section is coupled with at least a portion of the vaporization cooling pipe in one of the flue gas outlet sections to form a first heating surface, and the remaining vaporization cooling pipe in the flue gas inlet section is coupled with at least a portion of the vaporization cooling pipe in the other flue gas outlet section to form a second heating surface.

2. The three-way flue for waste heat recovery as described in claim 1, characterized in that: A portion of the vaporization cooling pipes in the flue gas inlet section are coupled with all the vaporization cooling pipes in one of the flue gas outlet sections to form the first heating surface, and the remaining vaporization cooling pipes in the flue gas inlet section are coupled with all the vaporization cooling pipes in the other flue gas outlet section to form the second heating surface.

3. The three-way flue for waste heat recovery as described in claim 2, characterized in that: The vaporization cooling pipe at the flue gas inlet section is defined as the first cooling pipe, and the vaporization cooling pipe at the flue gas outlet section is defined as the second cooling pipe; each first cooling pipe is coupled with multiple second cooling pipes.

4. The three-way flue for waste heat recovery as described in claim 3, characterized in that: When each first cooling pipe is coupled to two second cooling pipes, a Y-shaped trouser tube is used to complete the coupling. The two legs of the Y-shaped trouser tube are connected to the two second cooling pipes respectively, and the other end of the Y-shaped trouser tube is connected to the first cooling pipe.

5. The three-way flue for waste heat recovery as described in claim 1, characterized in that: A portion of the vaporization cooling pipe in the flue gas inlet section is coupled with the lower half of one of the flue gas outlet sections to form the first heating surface; the remaining vaporization cooling pipe in the flue gas inlet section is coupled with the lower half of the other flue gas outlet section to form the second heating surface; and the upper halves of the two flue gas outlet sections are coupled to form the third heating surface.

6. The three-way flue for waste heat recovery as described in any one of claims 1 to 5, characterized in that: The first heating surface is equipped with one or more inlet water headers and an equal number of return water headers.

7. The three-way flue for waste heat recovery as described in any one of claims 1 to 5, characterized in that: The second heating surface is equipped with one or more inlet water headers and an equal number of return water headers.

8. The three-way flue for waste heat recovery as described in claim 1, characterized in that: Both of the flue gas outlet sections are equipped with water-cooled valves.

9. A flue gas waste heat recovery system, comprising a vaporization cooling flue, characterized in that: It is also equipped with a three-way flue for waste heat recovery as described in any one of claims 1 to 8, wherein the flue gas inlet section is connected to the vaporization cooling flue, and the two flue gas outlet sections are respectively connected to a flue gas treatment mechanism.

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