Gas lifting cap assembly, gas cooling tower and flue gas purification system

Abstract

The invention relates to the technical field of flue gas treatment, in particular to a gas rising cap assembly, a gas cooling tower and a flue gas purification system. The gas rising cap assembly comprises a plurality of gas rising cap units, the gas rising cap units are arranged in parallel at intervals, and each gas rising cap unit comprises a guide cylinder and a first gas rising cap; the guide cylinder is used for guiding gas to rise for cooling; the first gas rising cap is arranged above the guide cylinder and at least covers the upper part of the guide cylinder; in the axial direction of the guide cylinder, a gap through which gas in the guide cylinder overflows is formed between the first gas rising cap and the upper part of the guide cylinder; at least part of the adjacent gas rising cap units share one first gas rising cap, and an opening is formed in the shared first gas rising cap and located between the upper portions of the adjacent guide cylinders; according to the gas lifting cap assembly, the gas-liquid separation efficiency can be improved, and the problem of low-load liquid leakage can be avoided or reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of flue gas treatment, and particularly to a riser cap assembly, a gas cooling tower and a flue gas purification system. Background Art

[0002] In the gas purification process, high-temperature flue gas is cooled by a quench cooler and then enters a gas cooling tower for gas-liquid separation. The traditional gas cooling tower adopts a single-layer umbrella-shaped riser cap structure, which can meet the basic separation requirements during full-load operation. However, it is found in the actual production process that when the device is operating at low load (such as below 60% of the design flow rate) or during start-up and shutdown phases, the gas-phase kinetic energy significantly decreases, and an effective gas-liquid separation interface cannot be formed at the riser cap. At this time, the gas-liquid two-phase hydrodynamics is unbalanced, resulting in a large number of liquid droplets being carried out by the gas-phase flow, causing serious liquid leakage, and thus forcing the liquid level in the pump sump of the gas cooling tower to be unable to be maintained.

[0003] To compensate for the liquid level loss, the operator has to frequently start and stop the circulation pump (once per hour) and continuously add production water, which not only increases the discharge of high-salt sewage, but also increases the risk of pump failure and the hidden danger of unplanned shutdown of the device. Especially when the spray flow rate is not adjusted in time, it is extremely easy to trigger the interlock shutdown of the outlet temperature of the gas cooling tower, causing double damage to the production safety and economy. Therefore, due to its fixed geometric shape and single separation level, the existing riser cap structure cannot dynamically adapt to a wide range of load fluctuation conditions, becoming a bottleneck restricting the flexible operation of the device. Summary of the Invention

[0004] In view of the above disadvantages of the prior art, the purpose of the present invention is to provide a riser cap assembly, a gas cooling tower and a flue gas purification system, which can improve the gas-liquid separation efficiency and avoid or reduce the occurrence of liquid leakage problems at low loads.

[0005] To achieve the above object and other related objects, the present invention provides a riser cap assembly, including a plurality of riser cap units, each of the riser cap units being arranged side by side at intervals, and each of the riser cap units including:

[0006] A draft tube for guiding the gas to rise and cool down;

[0007] A first riser cap disposed above the draft tube and covering at least the upper part of the draft tube; in the axial direction of the draft tube, there is a gap between the first riser cap and the upper part of the draft tube for the gas in the draft tube to overflow.

[0008] At least some adjacent riser cap units share a first riser cap, and an opening is provided on the shared first riser cap, and the opening is located between the upper parts of the adjacent draft tubes.

[0009] In an embodiment of the present invention, the shared first gas-lifting cap is in the shape of a flat plate or a downwardly curved arc.

[0010] In an embodiment of the present invention, at least a part of the first gas-lifting caps adjacent to the gas-lifting cap units are connected in series and / or in parallel to form the first gas-lifting cap shared by multiple draft tubes.

[0011] In an embodiment of the present invention, among the first gas-lifting caps above multiple draft tubes, the first gas-lifting caps located on the outer circle are connected in series to form a circle;

[0012] The first gas-lifting caps located on the inner side are arranged in series and / or in parallel along a straight line direction, and at least one end of the first gas-lifting caps arranged in a straight line in series and / or in parallel is connected to the first gas-lifting caps forming a circle.

[0013] In an embodiment of the present invention, each gas-lifting cap unit further includes a second gas-lifting cap. The second gas-lifting cap is in the shape of a cone. The second gas-lifting cap covers the upper part of the draft tube and is located below the first gas-lifting cap, and is arranged with a gap from the upper end of the draft tube.

[0014] In an embodiment of the present invention, the gas-lifting cap assembly further includes a first controller. The first gas-lifting cap and / or the second gas-lifting cap are supported above the draft tube through telescopic members. A first pressure sensor for real-time monitoring of gas-phase kinetic energy data is arranged corresponding to the inside of the draft tube.

[0015] The telescopic members and the first pressure sensor are both electrically connected to the first controller. The first controller is used to control the lifting of the telescopic members according to the gas-phase kinetic energy data detected by the first pressure sensor, so as to adjust the distance between the first gas-lifting cap and / or the second gas-lifting cap and the top end of the draft tube.

[0016] In an embodiment of the present invention, the gas-lifting cap assembly further includes an adjustable gas-lifting cap unit. The adjustable gas-lifting cap unit includes:

[0017] A third gas-lifting cap, located above the first gas-lifting cap,

[0018] A lifting member, the third gas-lifting cap is supported above the draft tube through the lifting member, and the lifting member is used to adjust the distance between the third gas-lifting cap and the upper end of the draft tube;

[0019] A second pressure sensor, arranged on the draft tube;

[0020] A second controller, electrically connected to the third gas-lifting cap and the second pressure sensor.

[0021] In view of the above disadvantages of the prior art, the purpose of the present invention is to provide a gas cooling tower, including the gas-lifting cap assembly described above.

[0022] In an embodiment of the present invention, the gas cooling tower includes:

[0023] A cooling tower body including a partition for partitioning the interior of the cooling tower body;

[0024] A liquid delivery pipe, one end of which penetrates into the cooling tower body and is located below the partition;

[0025] An infusion pipe, one end of which is communicated with the liquid delivery pipe, and the other end of which penetrates through the partition to guide the liquid above the partition into the liquid delivery pipe;

[0026] A packing plate, which is arranged above the gas lift cap assembly in the cooling tower body and is spaced apart from the gas lift cap assembly;

[0027] A spray head, which is arranged above the packing plate and is used for spraying downward;

[0028] Wherein, the gas lift cap assembly is arranged on the partition and is communicated with the lower part of the partition.

[0029] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a flue gas purification system, including the gas cooling tower described above, as well as a quench cooler, a gas cooling tower pump sump, and an electrostatic demister;

[0030] After the flue gas is cooled by the quench cooler, it is introduced into the gas cooling tower. After gas-liquid separation in the gas cooling tower, the liquid phase enters the gas cooling tower pump sump, and the gas phase enters the electrostatic demister.

[0031] To sum up, the present invention restricts the upward airflow path through the guide cylinder, increases the gas velocity in the cylinder to enhance the inertial collision effect of droplets, and promotes droplet aggregation; the shear action formed by the acceleration of the gas at the axial gap promotes the droplets to break away from the gas phase flow; the shared first gas lift cap opening guides the airflow of adjacent gas lift cap units to converge, generating a shear-induced vortex to achieve secondary separation and strengthen droplet aggregation. This design maintains a local critical gas velocity even when the gas kinetic energy decreases, ensuring the stability of the separation interface. The layout of multiple gas lift cap units in parallel forms a distributed airflow network, eliminating dead zones and balancing the pressure drop distribution. The structure of sharing the first gas lift cap between some adjacent units expands the separation interface area, provides a sufficient condensation attachment platform for the wet gas, significantly improves the gas-liquid separation efficiency, so that the device maintains a stable separation interface under wide load conditions, eliminates or significantly reduces the liquid leakage phenomenon, ensures the self-balancing of the pump sump liquid level, avoids frequent start and stop of the circulation pump, extends the service life of the equipment and eliminates the risk of unplanned shutdown. At the same time, it significantly reduces the production water make-up amount and the high-salt sewage treatment load, reduces water resource consumption and environmental protection costs, eliminates the outlet temperature interlock shutdown condition, and ensures the continuous and safe operation of the device. Description of the Drawings

[0032] 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 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 be obtained based on these drawings.

[0033] Figure 1 Schematic diagram of the internal structure of the gas cooling tower in an embodiment of the present invention;

[0034] Figure 2 One structural form diagram of the first gas-lifting cap arranged above the draft tube in an embodiment of the present invention;

[0035] Figure 3 Another structural form diagram of the first gas-lifting cap arranged above the draft tube in an embodiment of the present invention;

[0036] Figure 4 Position relationship diagram of the first gas-lifting cap and the second gas-lifting cap in an embodiment of the present invention;

[0037] Figure 5 Arrangement schematic diagram of the draft tube in the gas cooling tower in an embodiment of the present invention;

[0038] Figure 6 Schematic diagram of the flue gas purification system in an embodiment of the present invention;

[0039] Element number description: Gas cooling tower 100, Gas-lifting cap unit 1, Draft tube 11, Gap 111, First gas-lifting cap 12, Opening 121, Second gas-lifting cap 13, Adjustable gas-lifting cap unit 2, Third gas-lifting cap 21, Lifting member 22, Second pressure sensor 23, Cooling tower body 101, Partition 102, Liquid delivery pipe 103, Infusion pipe 104, Packing plate 105, Spray head 106, Quencher 200, Pump sump 300, Electrostatic demister 400, Weak acid stripping tower 500, Neutralization reactor 600, Safety sealing water 700, To drying tower 800, High-temperature flue gas X, Emergency water Y, Gas phase A, Liquid phase B. Detailed implementation manners

[0040] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. It should also be understood that the terms used in the embodiments of the present invention are for describing specific implementation manners and are not intended to limit the protection scope of the present invention. The test methods without specific conditions noted in the following embodiments are generally carried out under conventional conditions or according to the conditions recommended by each manufacturer.

[0041] Please refer to Figures 1 to 6 . It should be noted that the structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in this technology to understand and read, and are not intended to limit the limiting conditions under which the present invention can be implemented. Therefore, they do not have technical substantial significance. Any modification of the structure, change of the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle", and "one" cited in this specification are only for the convenience of clear narration and are not intended to limit the scope under which the present invention can be implemented. The change or adjustment of their relative relationships, without substantial change in the technical content, should also be regarded as the scope within which the present invention can be implemented.

[0042] When the embodiments give a numerical range, it should be understood that unless otherwise specified in the present invention, any value at both ends of each numerical range and any value between the two ends can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention, based on the understanding of those skilled in the art of the prior art and the description of the present invention, can also use any methods, devices, and materials of the prior art similar or equivalent to those described in the embodiments of the present invention to implement the present invention.

[0043] It should be understood that the solution before the improvement in this case is an immature technical solution of this case, and an immature technology does not necessarily mean the prior art.

[0044] High-temperature flue gas at 350 °C enters the purification unit from the regeneration unit. The gas first enters the quench cooler 200. The quench cooler 200 is a convective spray tower that performs cyclic cooling spray under adiabatic saturation to complete the washing and quenching of the furnace gas, removing most of the impurities. The furnace gas is quenched to 75 - 77 °C and then enters the gas cooling tower 100.

[0045] The process gas (including at least flue gas and water vapor) entering the gas cooling tower 100 completes the gas-liquid two-phase separation in the gas cooling tower 100. The liquid phase enters the bottom of the pump sump 300 of the gas cooling tower 100 and participates in the circulation process of the gas cooling tower 100. After the gas phase passes through the riser cap assembly and then through the packing plate 105 in the gas cooling tower 100, the process gas convectively contacts the weak acid cooled to 33 °C by the gas cooling tower circulation pump, ensuring that the temperature of the process gas leaving the gas cooling tower 100 is less than 35 °C, and then enters the electrostatic demister 400.

[0046] During the low-load operation and start-up heating-up stage of the original device, due to the independent multi-point setting of the riser caps in the gas cooling tower 100, the liquid leakage at each riser cap is too large to maintain the liquid level in the pump sump 300 of the gas cooling tower 100. For example, part of the liquid phase splashes into the draft tube 11 at each riser cap, or the gas phase containing water vapor in the gas cooling tower 100 enters the draft tube 11 under pressure, thus not meeting the requirements of low-load and start-up / shutdown operations. Specifically, the original device can meet the full-load operation requirements of the device, but during the start-up / shutdown and low-load operation of the device, the pump needs to be frequently started and stopped and water needs to be replenished, which easily leads to pump failures and the risk of device shutdown. At the same time, it increases the consumption of production water and the flow rate of sewage discharged. The traditional riser cap adopts a multi-point distributed single-layer umbrella structure, thus having the following defects: First, hydrodynamic imbalance, when the gas phase kinetic energy is insufficient at low load (<60% of the design flow rate), an effective gas-liquid separation interface cannot be formed; Second, the critical entrainment phenomenon: when the F factor (gas kinetic energy factor) < 0.6 m / s·(kg / m 3 )^0.5, the liquid droplet entrainment amount increases exponentially.

[0047] In the actual production test, the liquid leakage quantification data of the gas cooling tower 100 (32-U-6530 gas cooling tower) before the improvement of this case is shown in Table 1 below:

[0048] Test item 100% load 60% load Flue gas volume 113000 67800 Liquid leakage volume 0 16.7 t / h Pressure drop 8.4 Kpa 4.8 Kpa

[0049] Table 1

[0050] During the actual production process, that is, before the improvement of this case, during the low-load operation and start-up heating-up stage of the device, due to the excessive liquid leakage at the riser caps of the gas cooling tower 100, the liquid level in the pump sump 300 cannot be maintained, and the gas cooling tower pump needs to be short-stopped once per hour to maintain the liquid level, and the pump is frequently started. At the same time, 16.7 t / h of production water needs to be replenished. The replenished production water is sent to the sewage treatment device as high-salt sewage. In addition, during the start-up of the device, if the spray flow rate is not adjusted in time, it is easy to trigger the interlock shutdown due to the too high temperature at the outlet of the gas cooling tower 100. Therefore, there are many problems that need to be improved in this case.

[0051] Please refer to Figure 1, the present invention provides a riser cap assembly, which includes a plurality of riser cap units 1. Each of the riser cap units 1 is arranged side by side at intervals. Each of the riser cap units 1 includes a guide cylinder 11 and a first riser cap 12;

[0052] The guide cylinder 11 is used to guide the gas to rise and cool down; the first riser cap 12 is arranged above the guide cylinder 11 and at least covers the upper part of the guide cylinder 11; in the axial direction of the guide cylinder 11, there is a gap 111 for the gas in the guide cylinder 11 to overflow between the first riser cap 12 and the upper part of the guide cylinder 11;

[0053] At least some adjacent riser cap units 1 share one first riser cap 12, and an opening 121 is provided on the shared first riser cap 12. The opening 121 is located between the upper parts of adjacent guide cylinders 11.

[0054] It should be noted that, Figure 1 the infusion tube 104 in [] is not arranged directly below the guide cylinder 11. They are not on the same axis, and there is no guide cylinder 11 directly above the infusion tube 104. The guide cylinder 11 serves as a gas rising channel, and its cylinder wall guides the high-temperature gas to flow directionally to achieve the preliminary rectification of the air flow; the guide cylinder 11 can adopt a circular cross-section, a regular polygon cross-section (such as a hexagon or an octagon) or an elliptical cross-section. Different cross-section forms affect the separation efficiency by changing the boundary layer flow state. A first riser cap 12 is arranged above the axial top end of the guide cylinder 11. The first riser cap 12 at least covers the area of the upper open end of the guide cylinder 11 and completely shields the area above the cross-section of the guide cylinder 11; an axial gap 111 is reserved between the top end of the guide cylinder 11 and the first riser cap 12. This gap 111 forms a physical channel for the gas phase (at least including flue gas and water vapor) in the process gas to overflow. The height of the gap 111 is controlled by a bracket, a hydraulic lifting mechanism or a fixed support rib to ensure a good gas flow velocity under different gas phase flow rates. Further, at least some adjacent riser cap units 1 share the same first riser cap 12. The shared first riser cap 12 effectively reduces the number of separation interfaces and reduces the probability of local eddy current generation. An opening 121 is provided on the shared first riser cap 12. The opening 121 is located in the upper area between adjacent guide cylinders 11, that is, the opening 121 does not cover directly above each guide cylinder 11 to avoid the liquid phase directly falling into the guide cylinder 11 and causing leakage. For example, the position arrangement of the opening 121 is a rectangular opening centered on the axis of symmetry of adjacent guide cylinders 11, or honeycomb through holes distributed in an array on the shared first riser cap 12. The opening 121 can be a gradually expanding conical hole, a Venturi-type contraction hole or a straight-through round hole.

[0055] This solution solves the low-load leakage problem through the synergistic effects of multiple aspects: first, the guide tube 11 constrains the upward path of the airflow, increases the air velocity inside the guide tube 11 to enhance the inertial collision effect of the droplets, and promotes the aggregation of the droplets; second, the gas acceleration in the axial gap 111 forms a shearing effect, which prompts the droplets to separate from the gas phase flow due to inertia; finally, the opening 121 of the shared first air lift cap 12 guides the airflow of adjacent air lift cap units 1 to converge, forming a shear-induced vortex, which on the one hand realizes the secondary separation of the droplets and the flue gas, and on the other hand further promotes the aggregation of the droplets. When the kinetic energy of the gas phase decreases, although the flow rate of the convergent airflow at the opening 121 decreases, due to the large initial velocity, the local critical air velocity can still be maintained to avoid confusion of the separation interface. Multiple air lift cap units 1 are arranged in parallel to form a distributed airflow network, which effectively eliminates the airflow dead zone and balances the pressure drop distribution; finally, some adjacent air lift cap units 1 share the first air lift cap 12, thereby increasing the area of the first air lift cap 12. The first air lift cap 12 with a larger area provides a larger attachment platform for the process gas with water vapor, thereby facilitating the process gas with water vapor to be fully cooled, condensed and liquefied, that is, the first air lift cap 12 with a larger area is a water vapor. The steam process gas provides a larger gas-liquid separation interface, which is conducive to gas-liquid separation. By expanding the area of the first gas cap 12, the present invention can maintain a stable gas-liquid separation interface under low-load conditions (30%-60% of the design flow rate), completely eliminate leakage, and ensure the self-balancing of the liquid level in the pump tank 300; avoid frequent start and stop operations of the circulating pump, extend the service life of the pump, and eliminate the risk of unplanned shutdowns due to liquid level fluctuations; in addition, it also reduces the amount of production water added and the high-salt sewage treatment load, and simultaneously reduces water resource consumption and environmental protection treatment costs. At the same time, this case eliminates the outlet temperature interlock shutdown trigger condition to ensure the safety of continuous operation of the device.

[0056] like Figure 1 、 2 As shown in FIG3 , as an optional embodiment of the present invention, the shared first air lifting cap 12 is in the shape of a flat plate or a downwardly curved arc.

[0057] It should be noted that the shared first gas-lifting cap 12 serves as the shared separation interface for adjacent gas-lifting cap units 1, and its structural form directly affects the gas flow distribution and droplet removal efficiency. The flat plate configuration means that the main body of the gas-lifting cap has a planar geometric shape, including but not limited to rectangular flat plates and polygonal spliced flat plate structures. This configuration can simplify the manufacturing process and reduce production costs, and its planar characteristics provide a uniform impact surface for droplet aggregation. The downwardly curved arc shape means that the working surface of the gas-lifting cap has a continuous curvature, such as a single-curvature arc (such as a cylindrical surface segment) or a double-curvature arc (such as a spherical surface segment). The downwardly curved arc structure extends the gas flow path through the wall attachment effect, enhancing the centrifugal separation effect of droplets along the curved first gas-lifting cap 12 and the gas. The range of its radius of curvature needs to match the diameter of the draft tube 11 to optimize the flow field. Both configurations are fixed to the support structure by bolt connection, welding or integral molding, and the material is selected from fiberglass, stainless steel or nickel-based alloys to adapt to the corrosive environment. The flat first gas-lifting cap 12 forms a stable shear layer in the interval area between adjacent draft tubes 11. When the rising gas phase impacts the flat plate, a radial diffusion flow is generated. The droplets are separated from the gas phase body due to momentum decay. A low-pressure area is formed at the connection between the edge of the flat plate and the opening 121, promoting the separation of the liquid phase and the gas phase. For the downwardly curved arc-shaped first gas-lifting cap 12, the wall attachment effect of the curved surface fluid is utilized to make the gas move along the curvature tangent direction. The centripetal acceleration generated by the arc surface forces the droplets to be thrown towards the wall surface. At the same time, the curved structure extends the gas-liquid contact path, strengthening the inertial separation effect. The setting of the lowest point of the arc and the position of the opening 121 guides the gas-liquid separation. The gas phase continues to rise, and the liquid phase descends, improving the gas-liquid separation efficiency.

[0058] As Figures 1 - 3 shown, as an optional embodiment of this case, at least some of the first gas-lifting caps 12 adjacent to the gas-lifting cap units 1 are connected in series and / or in parallel to form the first gas-lifting cap 12 shared by multiple draft tubes 11.

[0059] It should be noted that, as Figure 2 shown, the series connection form is, for example, that the first gas-lifting caps 12 of multiple juxtaposed gas-lifting cap units 1 are connected in series in the horizontal direction to form a shared continuous first gas-lifting cap 12 structure. As Figure 3 shown, the parallel connection form is, for example, that multiple first gas-lifting caps 12 connected in series in the vertical direction are connected in parallel in the horizontal direction; the hybrid connection mode includes both series and parallel structures, such as nested series sub-units within a parallel unit group. The interface between the shared first gas-lifting cap 12 and the draft tube 11 is connected through a detachable flange or bracket, and its coverage range needs to ensure that the upper part of each draft tube 11 is completely covered. The series-parallel structure can form a continuous separation interface on the gas flow rising path, construct a large-area shared separation area, and balance the air pressure distribution between multiple draft tubes 11.

[0060] As Figure 2As shown in FIGS. 2 or 3, as an alternative embodiment of this case, among the first gas-lifting caps 12 above the plurality of draft tubes 11, the first gas-lifting caps 12 located on the outer ring are connected in series to form a circle;

[0061] The first gas-lifting caps 12 located on the inner side are arranged in series and / or in parallel in a straight line direction, and at least one end of the first gas-lifting caps 12 arranged in series and / or in parallel in a straight line is connected to the first gas-lifting caps 12 forming a circle.

[0062] It should be noted that the outer ring series structure means that the draft tube 11 groups arranged circumferentially along the tower wall are connected into an annular closed frame through continuous first gas-lifting caps 12. The inner straight layout means that the draft tubes 11 in the central area extend and are arranged axially or radially. In the series form, adjacent cylinders are connected by linear first gas-lifting caps 12, and in the parallel form, multiple draft tube 11 groups are covered by integrated first gas-lifting caps 12. At least one end of the inner straight first gas-lifting caps 12 is physically connected to the first gas-lifting caps 12 of the outer ring annular structure. The straight extension direction of the inner first gas-lifting caps 12 can be adapted to the requirements of the tower body flow field, and can adopt a transverse arrangement perpendicular to the gas flow direction, a longitudinal arrangement parallel to the gas flow, or an inclined staggered arrangement. In this case, through the outer ring annular series setting, a boundary constraint layer is formed to suppress the flow field distortion caused by the tower wall effect. The continuous curved surface of the annular first gas-lifting caps 12 guides the wall surface air flow to flow centripetally, eliminating the eddy dead zone generated by the traditional discrete gas-lifting caps at the tower wall and avoiding local liquid droplet accumulation. The inner straight series / parallel setting, the straight layout maintains the directional transportation of the central air flow, the series structure can increase the gas velocity at low load, the parallel structure disperses the high load air flow pressure, and the consistency between the straight extension direction and the mainstream direction reduces the flow resistance loss. The internal and external connection nodes realize the dynamic pressure difference balance of the air flow at the first gas-lifting caps 12 in the boundary area and the first gas-lifting caps 12 in the mainstream area. A flow guiding transition surface can be set at the connection to make the centripetal air flow in the outer ring and the axial air flow in the inner ring form a swirling fusion, strengthening the inertial collision and removal of liquid droplets in the confluence area, especially adapting to the flow rate mutation conditions during the start-up and shutdown stages.

[0063] As Figure 4 shown, as an alternative embodiment of this case, each gas-lifting cap unit 1 further includes a second gas-lifting cap 13. The second gas-lifting cap 13 is conical. The second gas-lifting cap 13 covers the upper part of the draft tube 11 and is located below the first gas-lifting cap 12, and a gap 111 is provided between the second gas-lifting cap 13 and the upper end of the draft tube 11.

[0064] It should be noted that the second gas-lifting cap 13 covers the upper part of the draft tube 11, and the diameter of the second gas-lifting cap 13 is larger than the outer diameter of the draft tube 11; the second gas-lifting cap 13 serves as the primary interface for gas-liquid separation, and its conical structure includes a cone with a constant cone angle and a cone with a variable cone angle. The cone apex angle range is designed to be 30° - 90°, preferably 45° - 60° to balance the flow resistance and separation efficiency. The second gas-lifting cap 13 can be installed on the upper end of the draft tube 11 through a bracket or directly connected to the partition 102 in the gas cooling tower 100, or the top of the second gas-lifting cap 13 is fixedly connected to the bottom surface of the first gas-lifting cap 12, but it is necessary to ensure that the axis of the cone coincides with the center of the draft tube 11. An annular gap 111 is formed between the lower edge of the conical second gas-lifting cap 13 and the top end of the draft tube 11, so as to facilitate the overflow of the gas in the draft tube 11. The rising gas accelerates within the conical surface of the second gas-lifting cap 13, and the liquid droplets impact the conical surface under the action of inertia to form a primary liquid film. The conical surface of the second gas-lifting cap 13 guides the liquid film to flow downward along the inclined surface and drip onto the partition 102, while the gas continues to rise, enabling the separation of the liquid phase and the gas phase. When the continuously rising gas passes through the annular gap 111, a high-speed jet is formed, generating a strong shearing action to strip the fine liquid droplets in the gas phase. After the large-sized liquid droplets are intercepted by the cone of the second gas-lifting cap 13, the residual liquid droplets in the gas phase are removed secondary by the first gas-lifting cap 12 above. When some of the liquid droplets dripping from the first gas-lifting cap 12 fall onto the top of the second gas-lifting cap 13, they slide down along the inclined surface of the top of the second gas-lifting cap 13 to the partition 102, and then flow into the infusion tube 104, ensuring the liquid level of the pump sump 300. And when there are more liquid droplets flowing downward along the inclined surface of the top of the second gas-lifting cap 13, a water curtain will be formed, and this water curtain can also promote the liquefaction of the water vapor in the gas overflowing from the axial gap 111 of the second gas-lifting cap 13, further promoting the gas-liquid separation. In addition, the conical second gas-lifting cap 13 reduces the steam liquefaction load of the first gas-lifting cap 12, avoiding overloading of the separation interface and failing to achieve the expected effect.

[0065] As an optional embodiment of this case, the gas-lifting cap assembly further includes a first controller. The first gas-lifting cap 12 and / or the second gas-lifting cap 13 are supported above the draft tube 11 through a telescopic member, and a first air pressure sensor for real-time monitoring of the gas-phase kinetic energy data is arranged corresponding to the inside of the draft tube 11;

[0066] The telescopic member and the first air pressure sensor are both electrically connected to the first controller. The first controller is used to control the lifting of the telescopic member according to the gas-phase kinetic energy data detected by the first air pressure sensor, so as to adjust the distance between the first gas-lifting cap 12 and / or the second gas-lifting cap 13 and the top end of the draft tube 11.

[0067] It should be noted that the telescopic member, as an actuator, includes two implementation forms: a multi-stage piston rod driven by a hydraulic cylinder, a lead screw-nut pair controlled by a stepping motor, or other driving methods that meet the requirements of this case. The first sensor is, for example, a pressure sensor, which is arranged in a stable airflow area inside the draft tube 11. The layout of its detection points adopts single-point monitoring on the central axis, three-point circumferential uniform monitoring, or nine-point matrix grid monitoring to collect pressure gradient data representing the kinetic energy of the gas phase in real time. The first controller is an embedded PLC, an industrial single-chip microcomputer, or a DCS system module. By establishing a mapping relationship between the air pressure data and the distance of the first gas-lifting cap 1, when the detection value of the first sensor is lower than the critical separation threshold, the first controller controls the telescopic member to reduce the distance to increase the gas flow rate; when the detection value is higher than the turbulence threshold, the distance is increased to suppress the pressure drop. The dynamic control of this case solves the separation failure caused by load fluctuations through closed-loop feedback; the pressure sensor captures the instantaneous change of the gas-phase kinetic energy inside the draft tube 11, and its data characteristics include, for example, the amplitude of static pressure fluctuation, the change rate of dynamic pressure gradient, or the turbulence intensity spectrum, to reflect the insufficient gas velocity at low load and the overloaded state of the gas flow at high load; during the distance adjustment process, by reducing the distance between the first gas-lifting cap 1 and the top of the draft tube 11, the area of the annular gap 111 shrinks, and the gas accelerates to form a strong shear field to enhance droplet removal; increasing the distance expands the flow channel to reduce the local resistance and avoid a sharp increase in pressure drop at high load. By converting the air pressure data into a distance adjustment instruction, compensating in advance for sudden load changes during start-up and shutdown phases, and feedback correction to eliminate steady-state operation deviations, the stability of the separation interface under all working conditions is ensured. Through full-condition adaptive separation, this case dynamically maintains the optimal gas-liquid separation state within the load range of 30%-120%, thereby eliminating or reducing the problems of liquid leakage at low load and pressure drop at high load, and eliminating the adjustment lag caused by manual intervention, preventing the outlet temperature of the air-cooled tower from interlocking and shutting down, and reducing the unplanned shutdown rate of the device; by precisely controlling the distance of the gas-lifting cap, the power consumption of the circulating pump is reduced, and the addition of production water and the energy consumption of sewage treatment are reduced.

[0068] As Figure 1 shown, as an optional embodiment of this case, the gas-lifting cap assembly further includes an adjustable gas-lifting cap unit 2, and the adjustable gas-lifting cap unit 2 includes a third gas-lifting cap 21, a lifting member 22, a second pressure sensor 23, and a second controller;

[0069] The third gas-lifting cap 21 is located above the first gas-lifting cap 12, and the third gas-lifting cap 21 is supported above the draft tube 11 by the lifting member 22. The lifting member 22 is used to adjust the distance between the third gas-lifting cap 21 and the upper end of the draft tube 11; the second pressure sensor 23 is arranged on the draft tube 11; the second controller is electrically connected to the third gas-lifting cap 21 and the second pressure sensor 23.

[0070] It should be noted that the third gas-lifting cap 21 is arranged above the first gas-lifting cap 12, and its structural form includes an umbrella-shaped dome, a multi-cone combination or a dish-shaped cover with a flow guide wing. The lifting member 22 is, for example, a hydraulic synchronous jacking system or a worm and worm gear mechanism driven by a servo motor, and the stroke range is designed according to 10%-40% of the diameter of the draft tube 11. The second air pressure sensor 23 is embedded in the stable air flow area in the upper middle part of the draft tube 11, and its sensing principle adopts piezoresistive, capacitive or resonant micromachining detection to collect dynamic pressure pulsation spectrum data in real time. The second controller is configured independently or integrated with the first controller, and the control strategy selects adaptive sliding mode control or neural network algorithm control, and establishes real-time data interaction with the lifting member 22 and the sensor through the bus protocol. In this case, the second air pressure sensor 23 captures the characteristics of the air flow kinetic energy distribution in the draft tube 11, and predicts the instability trend of the separation interface through the turbulent intensity spectrum analysis, and responds to the load mutation earlier than the traditional static monitoring; the lifting member 22 drives the third gas-lifting cap 21 to vertically displace, changing the cross-section of the interlayer flow channel between it and the lower gas-lifting cap. When the distance is reduced, a Venturi acceleration effect is formed to enhance the droplet collision, and when it is increased, the flow field is expanded to suppress the high-load pressure drop. The flow guide wing of the third gas-lifting cap 21 guides the air flow to form a swirling intersection with the lower separation interface, generating a low-pressure adsorption effect in the gas-liquid intersection area and strengthening the secondary removal of fine droplets. In practical applications, the third gas-lifting cap 21 cooperates with the hydraulic jacking system. The piezoresistive sensor array arranges 8 monitoring points along the circumference of the draft tube 11, and a mapping model of the air pressure gradient and the optimal distance is established. When it is detected that the F factor is lower than 0.3, the controller commands the third gas-lifting cap 21 to move down to form a secondary acceleration channel; when the F factor is higher than 1.2, it moves up to expand the flow channel, so that the gas-lifting cap assembly can quickly adapt to a large load step change and further improve the gas-liquid separation efficiency.

[0071] The present invention also provides a gas cooling tower 100, including the gas-lifting cap assembly described above.

[0072] As an optional embodiment of this case, the gas cooling tower 100 includes a cooling tower body 101, a liquid delivery pipe 103, an infusion pipe 104, a packing plate 105 and a spray head 106; the cooling tower body 101 includes a partition plate 102 for separating the interior of the cooling tower body 101; one end of the liquid delivery pipe 103 penetrates into the cooling tower body 101 and is located below the partition plate 102; one end of the infusion pipe 104 is communicated with the liquid delivery pipe 103, and the other end penetrates through the partition plate 102 to guide the liquid above the partition plate 102 into the liquid delivery pipe 103; the packing plate 105 is arranged above the gas-lifting cap assembly in the cooling tower body 101 and is arranged at an interval from the gas-lifting cap assembly; the spray head 106 is arranged above the packing plate 105 and is used for spraying downward; wherein, the gas-lifting cap assembly is arranged on the partition plate 102 and is communicated with the lower part of the partition plate 102.

[0073] It should be noted that the interior of the cooling tower body 101 is separated into two functional chambers, upper and lower, by a partition plate 102. The structure of the partition plate 102 is a flat sealing plate, and the material is selected from fiberglass laminate, Hastelloy composite plate, or rubber-lined carbon steel. The liquid delivery pipe 103 penetrates through the tower wall and extends to the lower chamber below the partition plate 102, and its interface form adopts flange seal connection or welded casing structure. The infusion pipe 104 serves as an inter-stage transfer channel, and its lower end is connected to the liquid delivery pipe 103 through a T-shaped tee, a Y-shaped diverter, or an annular header, and its upper end passes through the partition plate 102 to form a liquid phase passage. The packing plate 105 is arranged above the riser cap assembly, and the distance between the two is controlled by adjustable brackets, fixed support columns, or suspension chains. The packing types include regular corrugated plates, random Raschig rings, or high-efficiency regular packings. The distribution system of the spray heads 106 adopts rotating spray discs, pressure atomizing nozzles, or overflow trough distributors, and maintains the best mass transfer distance from the packing plate 105.

[0074] In this case, the physical isolation of the gas-liquid two-phase flow field by the partition plate 102 enables the lower chamber to maintain a stable gas-phase transmission process, and the upper chamber serves as a gas-liquid separation flow field. The process gas in the upper chamber is cooled, and the gas-phase mass transfer process is completed. The infusion pipe 104 directs the separated liquid phase back to the liquid delivery pipe 103, eliminating the gas-phase short-circuit phenomenon of the traditional structure. After the primary gas-liquid separation is completed by the riser cap assembly, the gas phase rises and makes a secondary countercurrent contact with the spray liquid on the packing plate 105. The distance between the packing plate 105 and the riser cap assembly is designed to form a buffer zone to prevent liquid droplets from being carried into the packing layer of the packing plate 105; the spray heads 106 form a uniform liquid film above the packing plate 105, and achieve efficient mass transfer with the rising gas phase on the packing surface. The blocking effect of the partition plate 102 eliminates the interference of the lower flow field on the upper gas-liquid distribution, ensures the temperature gradient distribution in each axial section of the whole tower, and is conducive to gas-liquid separation.

[0075] In this case, through the partitioned setting of the partition plate 102, the problem of liquid level fluctuation in the pump sump 300 is effectively solved. The cascaded structure of the infusion pipe 104 eliminates the water make-up requirement of 16.7 t / h, realizing zero external water make-up operation. The coordinated operation of the packing area and the riser cap assembly optimizes the gas-phase temperature gradient distribution, and the outlet gas temperature is stably controlled below 35 °C, thereby eliminating or improving the risk of temperature interlock shutdown.

[0076] The present invention also provides a flue gas purification system, including the gas cooling tower 100 as described above, as well as a quench cooler 200, a pump sump 300, and an electrostatic demister 400;

[0077] The flue gas is cooled by the quench cooler 200 and then introduced into the gas cooling tower 100. After gas-liquid separation in the gas cooling tower 100, the liquid phase enters the pump sump 300, and the gas phase enters the electrostatic demister 400.

[0078] It should be noted that, as a pretreatment unit, the quench cooler 200 has structural forms including a spray empty tower, a Venturi scrubber or a cyclone scrubber. The gas cooling tower 100 is of a vertical cylindrical, square multi-chamber or modular assembled type, and a single tower or multiple towers in parallel are configured according to the processing capacity requirements. The pump sump 300, as a liquid-phase collection unit, includes a conical bottom liquid collection tank, a flat bottom buffer tank or a composite tank body with an anti-vortex baffle, and maintains the liquid level balance through gravity flow or forced circulation. The electrostatic demister 400 includes a parallel plate type, a honeycomb tube type or a spiral electrode type, and the power supply system adopts a high-frequency pulse power supply, a DC constant voltage or an intelligent voltage regulation mode. Flexible connection of pipelines between each unit is achieved through a flange-connected bellows, expansion joint or hose to compensate for the thermal displacement stress. The quench cooler 200 rapidly cools the flue gas from 350 °C to 75 - 77 °C through adiabatic saturation cooling, and most soluble impurities are precipitated in the high-temperature section; the gas cooling tower 100 completes the gas-liquid equilibrium adjustment in the low-temperature zone of 33 - 35 °C, and the two-stage temperature difference design avoids the equipment stress concentration caused by thermal shock. The multi-stage adjustable structure of the riser cap assembly adapts to the fluctuation of the flue gas volume, and the series separation interface ensures zero escape of the liquid phase under low load; the electrostatic demister 400 captures the residual droplets through the self-adaptive adjustment of the electric field strength, forming a double insurance mechanism for gas-liquid separation; the differential pressure linkage control between the electrostatic demister 400 and the cooling tower reduces the energy consumption of the fan, and the system resistance is reduced compared with the traditional structure.

[0079] In this case, through the hierarchical interception of the series / parallel riser cap assembly, the effective separation interface is increased, the liquid droplet carry-over amount is reduced, and at the same time, the first riser cap 12 improves the gas flow stability, thereby significantly reducing the liquid leakage rate and greatly reducing the leakage amount of the spray liquid, meeting the operation requirements during the low load and start-up and shutdown periods of the device. The original single-layer riser cap structure is optimized into multiple series-connected riser caps. Specifically, the second riser cap 13 is used for preliminary gas-liquid separation to reduce the liquid-phase carry-over amount, the first riser cap 12 is used for secondary interception of liquid droplets to reduce the liquid leakage rate, and the third riser cap 21 is used for a dynamically adjustable multi-stage riser cap structure. The dynamically adjustable multi-stage riser cap structure solves the problem that the traditional fixed riser cap cannot adapt to the drastic load fluctuation (such as 30% - 120%), resulting in liquid leakage at low load and a sharp increase in pressure drop at high load. In this case, by designing a three-stage series-connected riser cap, where the third stage is a telescopic structure, the gas-phase kinetic energy (F factor) is monitored in real time through a pressure sensor, and a hydraulic device is driven to adjust the height and spacing of the third riser cap 21. If the liquid level of the pump sump 300 cannot be maintained after passing through the first riser cap 12 and the second riser cap 13 during low-load operation, the third riser cap 21 is added to further reduce the liquid leakage rate. The discrete arrangement of the traditional circular riser caps leads to uneven gas flow distribution and too high local pressure drop; in this case, by designing the riser cap unit 1 into other shapes, the uniformity of the gas flow channel is optimized, for example, by setting guide vanes to guide the gas flow to form a vortex to enhance separation.

[0080] The optimized operation data is shown in Table 2 below. This operation data is based on the settings of the first gas-lifting cap 1 and the second gas-lifting cap 13 in this case. The second gas-lifting cap 13 is arranged below the first gas-lifting cap 1, and the first gas-lifting cap 1 is connected to the upper end of the draft tube 11 through a bracket below the second gas-lifting cap 13, as Figure 1 shown in the partial structure of

[0081] Test item 100% load 60% load Flue gas volume 113000 67800 Liquid leakage volume 0 0 / h Pressure drop 8.4 Kpa 5.0 Kpa

[0082] Table 2

[0083] Compared with the prior art, the improved invention has at least the following effects: First, the improved gas-lifting cap assembly can effectively reduce the liquid leakage amount, improve the safety and reliability of the device, and avoid the unplanned shutdown of the device. Second, it avoids the repeated start and stop of the air-cooled tower circulating pump, prevents pump failures caused by repeated start and stop, and reduces economic losses by hundreds of thousands of yuan per unit. Third, it reduces the make-up of 16.7 t / h of production water and 16.7 t / h of high-salt sewage, reducing economic losses of thousands of yuan for production water and tens of thousands of yuan for high-salt sewage. Fourth, each time the device is shut down, the loss is reduced by more than one million yuan each time. Fifth, the transformation uses fiberglass material, and the air flow plate distribution can be adjusted according to different flue gas volumes. The process is simple and easy to operate. Sixth, the dynamically adjustable multi-stage gas-lifting cap structure can be adjusted in real time according to the operating state and can meet various operating conditions.

[0084] In summary, the present invention effectively overcomes some practical problems in the prior art and thus has high utilization value and practical significance.

[0085] The above embodiments are only illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A riser cap assembly, characterized in that, It includes multiple gas-lifting cap units, and each of the gas-lifting cap units is arranged side by side at intervals. Each of the gas-lifting cap units includes: A draft tube for guiding the gas to rise, cool and drop in temperature; A first gas-lifting cap arranged above the draft tube and at least covering the upper part of the draft tube; in the axial direction of the draft tube, there is a gap between the first gas-lifting cap and the upper part of the draft tube for the gas in the draft tube to overflow; At least some adjacent gas-lifting cap units share one first gas-lifting cap, and an opening is provided on the shared first gas-lifting cap, and the opening is located between the upper parts of adjacent draft tubes.

2. The gas-lifting cap assembly according to claim 1, wherein, The shared first gas-lifting cap is in a flat plate shape or a downwardly curved arc shape.

3. The gas lift cap assembly according to claim 1, characterized in that, At least some of the first gas-lifting caps of adjacent gas-lifting cap units are connected in series and / or in parallel to form the first gas-lifting cap shared by multiple draft tubes.

4. The gas-lifting cap assembly according to claim 2, characterized in that, Among the first gas-lifting caps above multiple draft tubes, the first gas-lifting caps located on the outer circle are connected in series to form a circle; The first gas-lifting caps located inside are arranged in series and / or in parallel in a straight line direction, and at least one end of the first gas-lifting caps arranged in series and / or in parallel in a straight line is connected to the first gas-lifting caps forming a circle.

5. The gas lift cap assembly according to claim 1, wherein Each of the gas-lifting cap units further includes a second gas-lifting cap, the second gas-lifting cap is in a conical shape, the second gas-lifting cap covers the upper part of the draft tube and is located below the first gas-lifting cap, and a gap is provided between the second gas-lifting cap and the upper end of the draft tube.

6. The gas-lifting cap assembly according to claim 1, wherein, It further includes a first controller. The first gas-lifting cap is supported above the draft tube by a telescopic member, and a first sensor for real-time monitoring of gas-phase kinetic energy data is provided corresponding to the inside of the draft tube. The telescopic member and the first sensor are both electrically connected to the first controller. The first controller is used to control the lifting of the telescopic member according to the gas-phase kinetic energy data detected by the first sensor to adjust the distance between the first gas-lifting cap and the top of the draft tube.

7. The gas lift cap assembly according to claim 1, wherein It further includes an adjustable gas-lifting cap unit. The adjustable gas-lifting cap unit includes: A third gas-lifting cap located above the first gas-lifting cap; A lifting member. The third gas-lifting cap is supported above the draft tube by the lifting member, and the lifting member is used to adjust the distance between the third gas-lifting cap and the upper end of the draft tube; A second air pressure sensor provided on the draft tube; A second controller electrically connected to the third gas-lifting cap and the second air pressure sensor.

8. A gas cooling tower, characterized in that, It includes the gas-lifting cap assembly according to any one of claims 1-7.

9. The gas cooling tower according to claim 8, wherein, The gas cooling tower includes: A cooling tower body including a partition for separating the inside of the cooling tower body; A liquid delivery pipe, one end of which penetrates into the cooling tower body and is located below the partition; An infusion pipe, one end of which is communicated with the liquid delivery pipe, and the other end penetrates through the partition to guide the liquid above the partition into the liquid delivery pipe; A packing plate provided above the gas-lifting cap assembly in the cooling tower body and arranged at an interval from the gas-lifting cap assembly; A spray head provided above the packing plate and used for spraying downward; Wherein, the gas-lifting cap assembly is arranged on the partition and communicated with the lower part of the partition.

10. A flue gas purification system, characterized in that, It includes the gas cooling tower according to any one of claims 8-9, as well as a quench cooler, an air-cooled tower pump sump and an electrostatic demister; After the flue gas is cooled by the quencher, it is introduced into the gas cooling tower. After gas-liquid separation in the gas cooling tower, the liquid phase enters the gas cooling tower pump sump, and the gas phase enters the electrostatic demister.

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