Falling film demisting and gas washing device

Abstract

The invention discloses a falling film demisting gas washing device which comprises a steam treatment part and a gas washing part, the folded plate demister comprises a shell and a #-shaped distribution plate, the shell comprises a first inner cavity, one end of the first inner cavity is communicated with the steam treatment part, and the other end of the first inner cavity is used for being communicated with an external steam compressor; the defoaming part comprises a plurality of baffle plates and a plurality of trapping hooks, each baffle plate comprises a plurality of peak parts, every two adjacent peak parts face the same direction in the second direction, every two adjacent peak parts face different directions in the first direction, each trapping hook comprises a connecting part and a hook part which are connected, and the hook parts and the corresponding peak parts are arranged at intervals in the second direction; the projections of the hook parts and the corresponding peak parts coincide; wherein external secondary steam can sequentially flow through the external falling film evaporator, the steam treatment part, the #-shaped distribution plate, the defoaming part and the external steam compressor. According to the steam compressor, entrainment carried in secondary steam can be reduced, and the influence on the efficiency of the steam compressor and the dynamic balance of the impeller is reduced.

Description

Technical Field

[0001] This invention relates to the field of falling film demisting and gas scrubbing devices, and particularly to a falling film demisting and gas scrubbing device. Background Technology

[0002] The secondary steam evaporated by the falling film evaporator is washed and demisted in the MVR (Mechanical Vapor Recompression) falling film evaporation system to improve the quality of the secondary steam. The MVR falling film evaporation system consists of a falling film evaporator, an MVR falling film demisting and washing device, a steam compressor, a falling film circulating pump, a falling film discharge pump, and material pipelines, steam pipelines, condensate pipelines, and other auxiliary facilities.

[0003] Current MVR falling film demister steam washing units generally consist of a vapor-liquid separator and a primary wire mesh demister built into the vapor-liquid separator. Secondary steam, evaporating from the material and carrying material droplets, first enters the vapor-liquid separator for preliminary vapor-liquid separation in the vapor phase space. The secondary steam then passes through the primary wire mesh demister to further remove entrained small droplets. Finally, the secondary steam exits the vapor-liquid separator and enters the MVR steam compressor via a secondary steam pipeline. The secondary steam is heated, pressurized, and decooled within the MVR steam compressor, then enters the shell side of the falling film evaporator as heating steam. After releasing latent heat to heat the material, the heating steam condenses into condensate, which is collected and discharged for reuse.

[0004] There are generally specific requirements for the discharged condensate. If too much secondary steam mist is carried, it can cause the condensate's conductivity, ion content, and other indicators to exceed standards. When the secondary steam passes through the steam compressor, it can easily corrode the impeller inside the compressor. Furthermore, if too much secondary steam mist is carried, the secondary steam will change from saturated steam to superheated steam after compression. The entrained droplets will evaporate, concentrate, and crystallize as the steam overheats. These crystals will adhere to the impeller and volute of the steam compressor, affecting compressor efficiency and even the impeller's dynamic balance. Summary of the Invention

[0005] The purpose of this invention is to solve the technical problem that excessive entrainment of secondary steam mist affects the efficiency of steam compressors and the dynamic balance of impellers. This invention provides a falling film demister gas scrubbing device, which can reduce the mist entrained in secondary steam and minimize its impact on the efficiency of steam compressors and the dynamic balance of impellers.

[0006] To address the aforementioned technical problems, embodiments of the present invention disclose a falling film demisting and gas scrubbing device, comprising:

[0007] The steam treatment section allows external secondary steam to flow into it from an external falling film evaporator.

[0008] A folding plate demister, comprising a shell and a grid distribution plate, the shell comprising a first inner cavity, the grid distribution plate being disposed in the first inner cavity along a first direction, one end of the first inner cavity being connected to the steam treatment section, and the other end of the first inner cavity being connected to an external steam compressor;

[0009] A defoaming section is disposed in the first inner cavity. Along the first direction, the defoaming section is spaced apart from the grid distribution plate. The defoaming section includes multiple baffles and multiple collecting hooks. Along the second direction, the multiple baffles are spaced apart. Each baffle includes multiple peaks. Along the second direction, the peaks of two adjacent baffles have the same orientation. Along the first direction, the peaks of two adjacent baffles have different orientations. Each collecting hook corresponds to each peak. Each collecting hook includes a connecting part and a hook part. The connecting part is connected to the corresponding peak. Along the second direction, the hook parts are spaced apart from the corresponding peaks. In the second direction, the projections of the hook parts and the corresponding peaks coincide. The second direction is perpendicular to the first direction.

[0010] Secondary steam from the outside can flow sequentially through the falling film evaporator, the steam treatment section, the grid distribution plate, the demister section, and the external steam compressor.

[0011] Using the above technical solution, the secondary steam enters the steam treatment section tangentially from the external falling film evaporator, and the secondary steam achieves primary mist separation.

[0012] After the initial mist separation, the secondary steam enters the first inner cavity of the baffle demister. It first passes through the grid distribution plate to ensure that the secondary steam can slow down and fill the first inner cavity evenly, thereby evenly distributing it on the baffle plate and improving the demisting capacity of the demister section.

[0013] A falling film demister scrubbing device can include multiple demister sections; for example, a falling film demister scrubbing device includes two demister sections. The secondary steam, uniformly dispersed by the grid-like distribution plate, first flows through the first demister section to achieve secondary mist separation. When the secondary steam passes the peak of the baffle plate in the first demister section, the liquid droplets collide with the hooks of the corresponding collecting hooks and are thus captured. Subsequently, under the influence of gravity, the liquid droplets captured by the collecting hooks flow downwards along the baffle plate of the first demister section.

[0014] Subsequently, the secondary steam from the first demister passes through the second demister for a third mist separation. Similarly, when the secondary steam passes the peak of the baffle plate in the second demister, the liquid droplets collide with the hooks of the corresponding collecting hooks and are captured. Then, under the influence of gravity, the liquid droplets captured by the collecting hooks flow downwards along the baffle plate of the second demister. The secondary steam passing through the second demister leaves the baffle demister and enters the steam compressor.

[0015] In this technical solution, the secondary steam undergoes primary mist separation via a steam treatment section, secondary mist separation via a first demister section, and tertiary mist separation via a second demister group. Compared to existing technologies where secondary steam only passes through a vapor-liquid separator and a single-stage wire mesh demister, this method involves more mist separation stages, effectively reducing the amount of mist entrained in the secondary steam and minimizing its impact on the efficiency of the steam compressor and the dynamic balance of the impeller.

[0016] Furthermore, since this technical solution uses a steam treatment unit and a baffle demister instead of the bulky gas-liquid separator in the prior art, the equipment diameter is greatly reduced, investment costs are lowered, and the floor space is reduced while ensuring demisting efficiency.

[0017] According to another specific embodiment of the present invention, the grid distribution plate includes a first distribution plate and a second distribution plate, the first distribution plate and the second distribution plate extending along the second direction, and along the third direction, the first distribution plate and the second distribution plate are spaced apart, the first distribution plate includes a first surface, the second distribution plate includes a second surface, and along the third direction, the first surface and the second surface are arranged opposite to each other, the distance between the first surface and the second surface increases towards the defoaming part along the first direction, and the third direction is perpendicular to the first direction;

[0018] The grid-shaped distribution plate includes a third distribution plate and a fourth distribution plate, which extend along the third direction. Along the second direction, the third distribution plate and the fourth distribution plate are spaced apart. The third distribution plate is connected to the first distribution plate and the second distribution plate, and the fourth distribution plate is connected to the first distribution plate and the second distribution plate. The third distribution plate includes a third surface, and the fourth distribution plate includes a fourth surface. Along the second direction, the third surface and the fourth surface are opposite to each other. The distance between the third surface and the fourth surface increases towards the demister along the first direction.

[0019] Using the above technical solution, when the secondary steam after primary mist separation enters the baffle demister, the secondary steam is relatively concentrated due to the small inlet. Therefore, the grid distribution plate is set to make the relatively concentrated secondary steam evenly fill the first inner cavity.

[0020] As the distance between the first and second surfaces increases along the first direction towards the demister, the secondary steam will diffuse along the first and second surfaces towards the demister when passing through the grid distribution plate. Similarly, as the distance between the third and fourth surfaces increases along the first direction towards the demister, the secondary steam will diffuse along the third and fourth surfaces towards the demister when passing through the grid distribution plate, ensuring that the secondary steam evenly fills the first inner cavity.

[0021] According to another specific embodiment of the present invention, along the second direction, the projection of each hook portion covers the projection of the corresponding peak portion.

[0022] Using the above technical solution, the projection of each hook covers the projection of its corresponding peak, ensuring that each hook and its corresponding peak are aligned along the second direction. In this way, the liquid droplets captured by the hooks can flow down the baffle plate instead of returning to the air and causing secondary or tertiary droplet separation failure.

[0023] According to another specific embodiment of the present invention, the steam treatment unit includes a cyclone separator, the cyclone separator includes a central air pipe and a first inner wall, the central air pipe includes a first outer wall, the first inner wall and the first outer wall define a liquid guiding channel, the falling film demisting and gas washing device includes a demister water tank, the demister water tank is connected to the liquid guiding channel and the first inner cavity respectively, the central air pipe is connected to the first inner cavity, and the demister water tank is used to collect the liquid mist separated by the secondary steam from the outside flowing through the liquid guiding channel and the first inner cavity.

[0024] Using the above technical solution, secondary steam enters the cyclone separator tangentially from the external falling film evaporator. The secondary steam rises tangentially, achieving primary mist separation, while the liquid droplets flow downwards into the liquid guide channel and then into the demister water tank. The secondary steam after primary mist separation enters the first inner chamber of the baffle demister through the central air pipe. After secondary and tertiary mist separation in the first inner chamber, the liquid droplets flowing down are collected by the demister water tank.

[0025] According to another specific embodiment of the present invention, the baffle demister includes a level gauge and a drain pump. The level gauge is electrically connected to the drain pump and the demister water tank, respectively. The level gauge is used to detect the liquid mist height in the demister water tank. The drain pump is started when the liquid mist height is higher than the middle position height of the demister water tank, and shut down when the liquid mist height is lower than a set height.

[0026] Using the above technical solution, if the liquid mist height is higher than the middle position of the demister water tank, no drain pump will start to discharge the liquid mist. Excessive liquid mist may then return to the first inner cavity, i.e., back into the secondary steam, causing secondary and tertiary mist separation to fail. Therefore, a level gauge is installed to detect the liquid mist height in the demister water tank in order to promptly discharge excess liquid mist.

[0027] According to another specific embodiment of the present invention, the steam treatment unit includes a spray scrubber, the falling film demisting scrubber includes a scrubbing steam circulation pump, one end of the scrubbing steam circulation pump is connected to the spray scrubber, the other end of the scrubbing steam circulation pump is used to connect to an external acid pump, and one end of the first inner cavity is connected to the spray scrubber.

[0028] The spray scrubber includes a second inner cavity and multiple spray heads. The multiple spray heads are disposed in the second inner cavity, which is connected to the first inner cavity. The multiple spray heads are spaced apart along the second direction. The scrubbing steam circulation pump includes a scrubbing steam pipe. The multiple spray heads are respectively connected to the scrubbing steam pipe. The orientation of the multiple spray heads is the same as the flow direction of the secondary steam from the outside. The falling film demisting scrubbing device includes a demister water tank. The demister water tank is connected to the second inner cavity and the first inner cavity respectively. The demister water tank is used to collect the liquid droplets separated from the secondary steam from the outside as it flows through the second inner cavity and the first inner cavity.

[0029] Using the above technical solution, the secondary steam may sometimes contain irritating gases such as ammonia. Therefore, a spray scrubber and a steam circulation pump are installed, with the other end of the steam circulation pump connected to an acid pump. The secondary steam enters the spray scrubber from an external falling film evaporator. After being sprayed with acid-containing water from the spray nozzles, it absorbs ammonia (i.e., spray scrubbing gas), achieving primary mist separation. The liquid droplets and the spray water containing the acid and ammonia reaction residue flow downwards into the demister water tank. The secondary steam after primary mist separation enters the first inner chamber of the baffle demister. The secondary steam undergoes secondary and tertiary mist separation in the first inner chamber, and the flowing liquid droplets are collected by the demister water tank.

[0030] According to another specific embodiment of the present invention, the falling film demister gas washing device further includes a liquid collecting component, which is connected to the first inner cavity, the second inner cavity and the demister water tank respectively, and the liquid collecting component is horizontally aligned with the baffle demister.

[0031] Using the above technical solution, the secondary steam after spray scrubbing undergoes a 90° turn before entering the baffle demister. The spray water containing acid and ammonia reacts with the ammonia, and due to inertia, most of it impacts the collecting element. Without a collecting element, the spray water containing acid and ammonia reacts directly impacts the baffle plates inside the demister, which over time will damage the baffle plates and affect their service life.

[0032] According to another specific embodiment of the present invention, the baffle demister includes a level gauge, the steam washing circulation pump includes a drain pipe, the level gauge is electrically connected to the drain pipe and the demister water tank respectively, the level gauge is used to detect the liquid mist height in the demister water tank, and the drain pipe is used to start when the liquid mist height is higher than the middle position height of the demister water tank, and to close when the liquid mist height is lower than a set height;

[0033] The falling film demisting and gas washing device also includes a water supply valve. The level gauge is electrically connected to the water supply valve and an external acid pump, respectively. The demister water tank is connected to the water supply valve and an external acid pump, respectively. The water supply valve is used to start the water supply valve and the external acid pump when the liquid mist height is lower than the set height.

[0034] Using the above technical solution, before the secondary steam enters the spray scrubber, condensate needs to be added to the demister water tank to the normal level (for example, the condensate level should be one-third of the demister water tank height). Then, the acid pump is started to add dilute sulfuric acid to the set pH value (e.g., pH 4-5), and the spray scrubber is then started. If the pH value is too low, it can easily corrode the demister water tank; if the pH value is too high, the condensate in the demister water tank will be alkaline and will lose its ability to absorb ammonia.

[0035] During the operation of the spray scrubber, if the liquid mist level exceeds the midpoint of the demister tank, the drain pipe will activate to remove the liquid mist. If the drain pipe does not activate to remove the liquid mist, the excess liquid mist may accumulate and return to the primary inner chamber, i.e., back into the secondary steam, causing secondary and tertiary mist separation to fail. Therefore, a level gauge is installed to detect the liquid mist level in the demister tank, so that the drain pipe can be activated in a timely manner to remove excess liquid mist from the demister tank.

[0036] When the liquid mist height is lower than the set height (the set height is, for example, one-fifth of the height of the demister water tank), the drain pipe is closed, and the water supply valve and acid pump are started respectively, so that the condensate in the demister water tank returns to the normal liquid level and the pH value returns to the set value.

[0037] According to another specific embodiment of the present invention, the baffle demister includes a pH meter, which is electrically connected to a drain pipe. The pH meter is used to detect the pH value of the liquid foam in the demister's water tank. The drain pipe is activated when the pH value is greater than or equal to a set value.

[0038] Using the above technical solution, if the pH is too high, the condensate in the demister tank will become alkaline and lose its ability to absorb ammonia. Therefore, when the pH value of the liquid mist in the demister tank is greater than or equal to the set value (e.g., pH=6), the drain pipe needs to be activated to discharge the liquid mist from the demister tank, making room for subsequent condensate and dilute sulfuric acid to re-enter.

[0039] According to another specific embodiment of the present invention, the steam treatment unit includes a spray scrubber, the falling film demisting scrubber includes a steam washing circulation pump, the steam washing circulation pump is connected to the spray scrubber, and one end of the first inner cavity is connected to the spray scrubber.

[0040] The spray scrubber includes a second inner cavity and multiple spray heads. The multiple spray heads are disposed in the second inner cavity, which is connected to the first inner cavity. The multiple spray heads are spaced apart along the second direction. The scrubbing steam circulation pump includes a scrubbing steam pipe. The multiple spray heads are respectively connected to the scrubbing steam pipe. The orientation of the multiple spray heads is the same as the flow direction of the secondary steam from the outside. The falling film demisting scrubbing device includes a demister water tank. The demister water tank is connected to the second inner cavity and the first inner cavity respectively. The demister water tank is used to collect the liquid droplets separated from the secondary steam from the outside as it flows through the second inner cavity and the first inner cavity.

[0041] Using the above technical solution, when encountering materials with high foaming properties, the secondary steam may contain a particularly large amount of mist. Therefore, a spray scrubber and a steam circulation pump are installed. The secondary steam enters the spray scrubber from an external falling film evaporator. After being sprayed with condensate water from the spray nozzles (i.e., spray scrubbing), most of the liquid mist is carried away by the spray water, achieving primary mist separation. The liquid mist and spray water then flow downwards into the demister water tank. The secondary steam after primary mist separation enters the first inner chamber of the baffle demister. The secondary steam undergoes secondary and tertiary mist separation in the first inner chamber, and the liquid mist flowing down is collected by the demister water tank.

[0042] According to another specific embodiment of the present invention, the falling film demister gas washing device further includes a liquid collecting component, which is connected to the first inner cavity, the second inner cavity and the demister water tank respectively, and the liquid collecting component is horizontally aligned with the baffle demister.

[0043] Using the above technical solution, the secondary steam after spray scrubbing undergoes a 90° turn before entering the baffle demister, causing most of the spray water to impact the liquid collecting element due to inertia. Without a liquid collecting element, the spray water would directly impact the baffle plates inside the baffle demister, which would damage the baffle plates over time and affect their service life.

[0044] According to another specific embodiment of the present invention, the baffle demister includes a level gauge and a conductivity meter, the steam washing circulation pump includes a drain pipe, the level gauge is electrically connected to the drain pipe and the demister water tank respectively, the level gauge is used to detect the liquid mist height in the demister water tank, and the drain pipe is activated when the liquid mist height is higher than the middle position height of the demister water tank; the conductivity meter is used to detect the conductivity value of the liquid mist in the demister water tank, and the drain pipe is activated when the conductivity value is higher than a set value, and closed when the liquid mist height is lower than a set height;

[0045] The falling film demisting and gas washing device also includes a water supply valve, which is electrically connected to the level gauge and connected to the demister water tank. The water supply valve is activated when the liquid mist height is lower than the set height.

[0046] Using the above technical solution, before the secondary steam enters the spray scrubber, condensate needs to be added to the demister water tank to the normal level (for example, the height of the condensate should be one-third of the height of the demister water tank), and then the spray scrubber should be started.

[0047] During the operation of the spray scrubber, if the liquid mist level is higher than the middle position of the demister water tank, or if the conductivity of the liquid mist in the demister water tank exceeds a set value (this set value depends on the specific site conditions, for example, it could be 5000 μs / cm), the drain pipe will activate to remove the liquid mist. If the drain pipe does not activate to remove the liquid mist, excessive liquid mist may accumulate and return to the first inner cavity, i.e., back into the secondary steam, causing secondary and tertiary mist separation to fail. Therefore, a level gauge is installed to detect the liquid mist level in the demister water tank so that the drain pipe can be activated in a timely manner to remove excess liquid mist from the demister water tank.

[0048] When the liquid mist height is lower than the set height (the set height is, for example, one-fifth of the height of the demister water tank), the drain pipe is closed and the water supply valve is activated, so that the condensate in the demister water tank returns to the normal level.

[0049] According to another specific embodiment of the present invention, the baffle demister includes a spray section, the spray section includes a first water pipe and a nozzle, one end of the first water pipe is connected to an external water pump, the other end of the first water pipe is connected to the nozzle, the nozzle is disposed in the first inner cavity, and along the first direction, the nozzle is disposed toward the plurality of baffles.

[0050] Using the above technical solution, some entrained liquid droplets may adhere to the baffles when the secondary steam passes through them. Over time, this can cause blockage between adjacent baffles, affecting the demisting effect. Therefore, a spray section is installed, with nozzles spraying towards the baffles to wash away the liquid droplets adhering to them. Attached Figure Description

[0051] Figure 1 A schematic diagram of the falling film demisting and gas washing device in Embodiment 1 of the present invention is shown.

[0052] Figure 2 A schematic diagram of the falling film demisting and gas washing device in Embodiment 2 of the present invention is shown.

[0053] Figure 3 A schematic diagram of the falling film demisting and gas washing device in Embodiment 3 of the present invention is shown.

[0054] Figure 4 A top view of the baffle demister in an embodiment of the present invention is shown.

[0055] Figure 5A A schematic diagram of the defoaming section in an embodiment of the present invention is shown.

[0056] Figure 5B This invention illustrates an embodiment of the invention. Figure 5A A magnified view of a portion of region A in the middle.

[0057] Figure 6A A stereoscopic view of the grid distribution plate in an embodiment of the present invention is shown. Figure 1 .

[0058] Figure 6B A stereoscopic view of the grid distribution plate in an embodiment of the present invention is shown. Figure 2 .

[0059] Figure 7 A schematic diagram of a cyclone separator in an embodiment of the present invention is shown.

[0060] Figure 8 A schematic diagram of a spray scrubber in an embodiment of the present invention is shown.

[0061] Explanation of reference numerals in the attached figures

[0062] Steam treatment section 10;

[0063] Cyclone separator 11;

[0064] Central trachea 111; First outer wall 1111;

[0065] First inner wall 112;

[0066] Fluid delivery channel 113;

[0067] Spray scrubber 12;

[0068] Second inner cavity 121; Spray head 122;

[0069] Folding plate demister 20;

[0070] Outer shell 21; First inner cavity 211;

[0071] 22-grid distribution board;

[0072] First distribution plate 221; First surface 2211;

[0073] Second distribution plate 222; Second surface 2221;

[0074] Third distribution plate 223; Third surface 2231;

[0075] Fourth distribution plate 224; Fourth surface 2241;

[0076] Through hole 225;

[0077] Drainage pump 23;

[0078] Spray section 24;

[0079] First water pipe 241; Sprinkler head 242;

[0080] Defoaming section 30;

[0081] Baffle 31; Peak 311;

[0082] 32; 321; 322;

[0083] Demister water tank 40;

[0084] 50mm steam washing circulation pump;

[0085] Steam washing pipe 51; sewage pipe 52;

[0086] Liquid collection unit 60;

[0087] Water supply valve 70;

[0088] Falling film evaporator 100;

[0089] 200 acid pump;

[0090] Water pump 300;

[0091] Steam compressor 400. Detailed Implementation

[0092] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention is presented in conjunction with preferred embodiments, this does not mean that the features of the invention are limited to these embodiments. On the contrary, the purpose of describing the invention in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of the present invention. To provide a deep understanding of the invention, many specific details will be included in the following description. The invention may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of the invention, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0093] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0094] In the description of this embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the product of the invention is usually placed in during use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0095] The terms “first”, “second”, etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0096] In the description of this embodiment, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment based on the specific circumstances.

[0097] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0098] Secondary steam is obtained by evaporation from materials and carries material droplets. There are three operating conditions based on the amount of material carried in the secondary steam and the acidity / alkalinity of the gas. The first is the conventional operating condition, where the secondary steam carries a moderate amount of liquid droplets and the entrained gas is neutral. The standard for moderate liquid droplets is: if a small-scale evaporation test is conducted on the material, and the conductivity of the condensate is ≤500μS / cm, then the secondary steam carries a moderate amount of liquid droplets. The second is the ammonia-containing secondary steam operating condition, where the secondary steam carries irritating gases such as ammonia. The third is the high-liquid-droplet secondary steam operating condition, where the secondary steam carries a particularly large amount of mist droplets when encountering materials with high foaming properties. Generally, materials with high foaming properties have the following characteristics: (1) COD (Chemical Oxygen Demand) ≥500ppm; (2) Alkalinity ≥1000ppm; (3) Hardness ≥500ppm. Materials possessing any one of these characteristics are considered to have high foaming properties. The standard for excessive entrainment of mist is as follows: if a small-scale evaporation test is conducted on the material, and the conductivity of the condensate is >500μS / cm, or a large number of bubbles can be seen in the material during the small-scale test, then the secondary steam carries excessive mist.

[0099] Therefore, this application provides a falling film demisting gas scrubbing device for the above three working conditions.

[0100] refer to Figures 1 to 3 This application provides a falling film demister gas scrubbing device, which includes a steam treatment section 10, a baffle demister 20, and two demister sections 30. Secondary steam from the outside (not shown in the figure) can flow into the steam treatment section 10 from the external falling film evaporator 100.

[0101] refer to Figure 1 and Figure 4 The baffle demister 20 includes a housing 21 and a grid distribution plate 22. The housing 21 includes a first inner cavity 211, and the grid distribution plate 22 is disposed in the first inner cavity 211. Along the first direction X, one end of the first inner cavity 211 is connected to the steam treatment unit 10, and the other end of the first inner cavity 211 is used to connect to the external steam compressor 400.

[0102] refer to Figures 4 to 5B Two demisters 30 are disposed in the first inner cavity 211. Along the first direction X, the first demister 30 is spaced apart from the grid distribution plate 22. Each demister 30 includes multiple baffles 31 and multiple collecting hooks 32. Along the second direction Y, the multiple baffles 31 are spaced apart. Each baffle 31 includes three peaks 311. Along the second direction Y, the peaks 311 of two adjacent baffles 31 face the same direction. Along the first direction X, the peaks 311 of two adjacent baffles 31 face different directions.

[0103] Each trapping hook 32 corresponds to each peak 311. Each trapping hook 32 includes a connecting portion 321 and a hook portion 322, with the connecting portion 321 connected to the corresponding peak portion 311. Along the second direction Y, the hook portions 322 and the corresponding peak portions 311 are spaced apart, and in the second direction Y, the projections of the hook portions 322 and the corresponding peak portions 311 coincide. The second direction Y is perpendicular to the first direction X.

[0104] Secondary steam from the outside can flow sequentially through the external falling film evaporator 100, the steam treatment section 10, the grid distribution plate 22, the demister section 30, and the external steam compressor 400.

[0105] Using the above technical solution, the secondary steam enters the steam treatment section 10 tangentially from the external falling film evaporator 100, and the secondary steam achieves primary mist separation.

[0106] After the initial mist separation, the secondary steam enters the first inner cavity 211 of the baffle demister 20. It first passes through the grid distribution plate 22 to ensure that the secondary steam can slow down and fill the first inner cavity 211 evenly, thereby evenly distributing it onto the baffle plate 31 and improving the demisting capacity of the demister section 30.

[0107] The secondary steam, after being evenly dispersed by the grid distribution plate 22, first flows through the first demister 30 to achieve secondary mist separation. When the secondary steam passes through the peak 311 of the baffle plate 31 of the first demister 30, the liquid mist will hit the hook 322 of the collecting hook 32 corresponding to the peak 311 and be captured by the hook 322. Then, under the action of gravity, the liquid mist captured by the collecting hook 32 flows downward along the baffle plate 31 of the first demister 30.

[0108] Subsequently, the secondary steam passing through the first demister 30 will pass through the second demister 30 to achieve tertiary mist separation. Similarly, when the secondary steam passes through the peak 311 of the baffle 31 in the second demister 30, the liquid droplets will collide with the hook 322 of the collecting hook 32 corresponding to the peak 311, and thus be captured by the hook 322. Then, under the action of gravity, the liquid droplets captured by the collecting hook 32 flow downward along the baffle 31 of the second demister 30. The secondary steam passing through the second demister 30 leaves the baffle demister 20 and enters the steam compressor 400.

[0109] In this technical solution, the secondary steam undergoes primary mist separation via the steam treatment section 10, secondary mist separation via the first demister section 30, and tertiary mist separation via the second demister section 30. Compared to existing technologies where the secondary steam only passes through a vapor-liquid separator and a single-stage wire mesh demister, this method involves more mist separation stages, effectively reducing the amount of mist entrained in the secondary steam and minimizing its impact on the efficiency and impeller dynamic balance of the steam compressor 400.

[0110] It should be noted that the number of demisters 30 included in the falling film demister scrubbing device is not specifically limited in this embodiment. For example, in other possible implementations, the number of demisters 30 included in the falling film demister scrubbing device may be three, four, etc. Similarly, the number of peaks 311 included in each baffle 31 is not specifically limited in this embodiment. For example, in other possible implementations, the number of peaks 311 included in each baffle 31 may be two, four, etc.

[0111] In some possible implementations, refer to Figure 5A and 5B Along the second direction Y, the projection of each hook 322 covers the projection of the corresponding peak 311.

[0112] Using the above technical solution, the projection of each hook 322 covers the projection of its corresponding peak 311, ensuring that each hook 322 and its corresponding peak 311 are correspondingly set along the second direction Y. In this way, the liquid droplets captured by the capturing hook 32 can flow down along the baffle 31 instead of returning to the air and causing secondary or tertiary droplet separation failure.

[0113] In some possible implementations, refer to Figure 4 , Figure 6A and 6B The grid-like distribution plate 22 includes a first distribution plate 221 and a second distribution plate 222, both of which are cuboids. The first distribution plate 221 and the second distribution plate 222 extend along a second direction Y and are spaced apart along a third direction Z. The first distribution plate 221 includes a first surface 2211, and the second distribution plate 222 includes a second surface 2221. Along the third direction Z, the first surface 2211 and the second surface 2221 are positioned opposite each other, and the distance between the first surface 2211 and the second surface 2221 increases along the first direction X towards the demister 30. The third direction Z is perpendicular to the first direction X.

[0114] The grid-shaped distribution plate 22 includes a third distribution plate 223 and a fourth distribution plate 224, both of which are cuboids. The third distribution plate 223 and the fourth distribution plate 224 extend along a third direction Z and are spaced apart along a second direction Y. The third distribution plate 223 is connected to the first distribution plate 221 and the second distribution plate 222, and the fourth distribution plate 224 is also connected to the first distribution plate 221 and the second distribution plate 222. The third distribution plate 223 includes a third surface 2231, and the fourth distribution plate 224 includes a fourth surface 2241. Along the second direction Y, the third surface 2231 and the fourth surface 2241 are positioned opposite each other, and the distance between the third surface 2231 and the fourth surface 2241 increases towards the demister 30 along the first direction X.

[0115] The first distribution plate 221, the second distribution plate 222, the third distribution plate 223 and the fourth distribution plate 224 are respectively arranged in a cross pattern to form a square through hole 225, and the cross-sectional area of ​​the through hole 225 gradually increases along the first direction X toward the defoaming part 30, that is, the grid distribution plate 22 is "trumpet-shaped".

[0116] Using the above technical solution, when the secondary steam after the first mist separation enters the baffle demister 20, the secondary steam is relatively concentrated due to the small inlet. Therefore, the grid distribution plate 22 is set so that the relatively concentrated secondary steam can evenly fill the first inner cavity 211.

[0117] Since the distance between the first surface 2211 and the second surface 2221 increases along the first direction X towards the demister 30, the secondary steam will diffuse along the first surface 2211 and the second surface 2221 towards the demister 30 when passing through the grid distribution plate 22. Similarly, since the distance between the third surface 2231 and the fourth surface 2241 increases along the first direction X towards the demister 30, the secondary steam will diffuse along the third surface 2231 and the fourth surface 2241 towards the demister 30 when passing through the grid distribution plate 22, ensuring that the secondary steam evenly fills the first inner cavity 211.

[0118] It should be noted that the shapes of the first distribution plate 221, the second distribution plate 222, the third distribution plate 223, and the fourth distribution plate 224 are not specifically limited in this embodiment. For example, in other possible implementations, the shapes of the first distribution plate 221, the second distribution plate 222, the third distribution plate 223, and the fourth distribution plate 224 can be elliptical, wavy, etc.

[0119] In some possible implementations, refer to Figure 1 and Figure 4The baffle demister 20 includes a spray section 24, which includes two sets of first water pipes 241 and nozzles 242. One end of the first water pipe 241 is connected to an external water pump 300, and the other end of the first water pipe 241 is connected to the nozzles 242. The nozzles 242 are located in the first inner cavity 211 and are positioned towards multiple baffles 31 along the first direction X.

[0120] Using the above technical solution, when the secondary steam passes through the baffle 31, some entrained liquid droplets may adhere to the baffle 31. Over time, this can cause blockage between adjacent baffles 31, affecting the defoaming effect. Therefore, a spray section 24 is provided, with nozzles 242 spraying towards the baffle 31 to wash away the liquid droplets adhering to the baffle 31.

[0121] It should be noted that the number of sets of the first water pipe 241 and the nozzle 242 included in the spray unit 24 is not specifically limited in this application embodiment. For example, in other possible embodiments, the number of sets of the first water pipe 241 and the nozzle 242 included in the spray unit 24 may be three, four, etc.

[0122] Example 1

[0123] Based on the above implementation methods, the falling film demisting gas scrubbing device for handling conventional working conditions is first introduced, namely Example 1.

[0124] In some possible implementations, refer to Figure 1 , Figure 4 and Figure 7 The steam treatment unit 10 includes a cyclone separator 11, which includes a central air pipe 111 and a first inner wall 112. The central air pipe 111 includes a first outer wall 1111, and the first inner wall 112 and the first outer wall 1111 define a liquid guiding channel 113. The falling film demister washing device includes a demister water tank 40, which is connected to the liquid guiding channel 113 and the first inner cavity 211, respectively. The central air pipe 111 is connected to the first inner cavity 211. The demister water tank 40 is used to collect the liquid droplets separated from the secondary steam flowing through the liquid guiding channel 113 and the first inner cavity 211.

[0125] Using the above technical solution, secondary steam enters tangentially into the cyclone separator 11 from the external falling film evaporator 100. The secondary steam rotates and rises tangentially to achieve primary mist separation, while the liquid droplets flow downwards into the liquid guide channel 113 and then into the demister water tank 40. The secondary steam after primary mist separation enters the first inner cavity 211 of the baffle demister 20 from the central air pipe 111. After secondary and tertiary mist separation, the liquid droplets flowing down are collected by the demister water tank 40.

[0126] In some possible implementations, refer to Figure 1The baffle demister 20 includes a level gauge (not shown in the figure) and a drain pump 23. The level gauge is electrically connected to the drain pump 23 and the demister water tank 40. The level gauge is used to detect the liquid mist level in the demister water tank 40. The drain pump 23 is activated when the liquid mist level is higher than the middle position of the demister water tank 40, and deactivated when the liquid mist level is lower than the set level.

[0127] Using the above technical solution, if the liquid mist height is higher than the middle position of the demister water tank 40, no drain pump 23 will start to discharge the liquid mist. Excessive liquid mist may then return to the first inner cavity 211, i.e., back into the secondary steam, causing secondary and tertiary mist separation to fail. Therefore, a level gauge is installed to detect the liquid mist height in the demister water tank 40 in order to promptly discharge excess liquid mist from the demister water tank 40.

[0128] Next, the working principle of the falling film demisting and gas washing device in Example 1 will be explained in detail.

[0129] refer to Figure 1 , Figures 4 to 7 Secondary steam enters the cyclone separator 11 tangentially. The secondary steam rotates and rises tangentially within the cyclone separator 11, achieving primary mist separation. The liquid mist flows downwards by gravity into the liquid guide channel 113 and then into the demister water tank 40. After primary mist separation, the secondary steam turns and enters the central air pipe 111, from which it enters the first inner cavity 211 of the baffle demister 20.

[0130] The secondary steam entering the first inner cavity 211 first passes through the "trumpet-shaped" grid distribution plate 22, and spreads along the first surface 2211, the second surface 2221, the third surface 2231 and the fourth surface 2241 towards the demister section 30, ensuring that the secondary steam evenly fills the first inner cavity 211.

[0131] Subsequently, the secondary steam passes through two demister sections 30 to achieve secondary and tertiary mist separation. When the secondary steam passes through the peak 311 of the baffle 31 in the demister section 30, the liquid droplets collide with the hook 322 of the collecting hook 32 corresponding to the peak 311, and are thus captured by the hook 322. Then, under the action of gravity, the liquid droplets captured by the collecting hook 32 flow downward along the baffle 31 and finally flow into the demister water tank 40. The secondary steam after the tertiary mist separation flows into the steam compressor 400.

[0132] During the operation of the falling film demisting and gas scrubbing device, the level gauge will detect the liquid mist height in the demister water tank 40. When the liquid mist height is higher than the middle position height of the demister water tank 40, the drain pump 23 will start; when the liquid mist height is lower than the set height (the set height is, for example, one-fifth of the height of the demister water tank 40), the drain pump 23 will shut down.

[0133] It should be noted that the embodiments of this application do not impose specific limitations on the setting height. For example, in other possible implementations, the setting height may be one-quarter or one-sixth of the height of the demister water tank 40, etc. The setting height depends on the specific site conditions.

[0134] Example 2

[0135] Next, we will introduce the falling film demister gas washing device used to handle ammonia-containing secondary steam conditions, namely Example 2.

[0136] In some possible implementations, refer to Figure 2 , Figure 4 and Figure 8 The steam treatment unit 10 includes a spray scrubber 12, and the falling film demisting scrubber includes a steam washing circulation pump 50. One end of the steam washing circulation pump 50 is connected to the spray scrubber 12, and the other end of the steam washing circulation pump 50 is used to connect to an external acid pump 200. One end of the first inner cavity 211 is connected to the spray scrubber 12.

[0137] The spray scrubber 12 includes a second inner cavity 121 and three spray heads 122. The three spray heads 122 are located in the second inner cavity 121, which is connected to the first inner cavity 211. The three spray heads 122 are spaced apart along a second direction Y. The scrubbing steam circulation pump 50 includes a scrubbing steam pipe 51, and the three spray heads 122 are respectively connected to the scrubbing steam pipe 51. The orientation of the three spray heads 122 is the same as the flow direction of the secondary steam from the outside. The demister water tank 40 is connected to both the second inner cavity 121 and the first inner cavity 211. The demister water tank 40 is used to collect the liquid mist separated from the secondary steam flowing through the second inner cavity 121 and the first inner cavity 211.

[0138] Using the above technical solution, the secondary steam may sometimes contain irritating gases such as ammonia. Therefore, a spray scrubber 12 and a steam washing circulation pump 50 are installed, with the other end of the steam washing circulation pump 50 connected to an acid addition pump 200. The secondary steam enters the spray scrubber 12 from the external falling film evaporator 100. After being sprayed by acid-containing water sprayed from the spray head 122, it absorbs ammonia (i.e., spray scrubbing gas), achieving primary mist separation. The liquid droplets and the spray water containing acid and ammonia reacting together flow downwards into the demister water tank 40. The secondary steam after primary mist separation enters the first inner cavity 211 of the baffle demister 20. The secondary steam undergoes secondary and tertiary mist separation in the first inner cavity 211, and the liquid droplets flowing down are collected by the demister water tank 40.

[0139] It should be noted that the number of spray heads 122 is not specifically limited in this application embodiment. For example, in other possible implementations, the number of spray heads 122 may be four, five, etc.

[0140] In some possible implementations, refer to Figure 2 and Figure 4 The falling film demisting and gas washing device also includes a liquid collection component 60, which is connected to the first inner cavity 211, the second inner cavity 121 and the demister water tank 40 respectively, and the liquid collection component 60 is horizontally aligned with the baffle demister 20.

[0141] Using the above technical solution, since the secondary steam after spray scrubbing undergoes a 90° turn before entering the baffle demister 20, most of the spray water containing acid and ammonia reacts with the liquid collector 60 due to inertia. Without the liquid collector 60, the spray water containing acid and ammonia would directly impact the baffle plate 31 inside the baffle demister 20, which would damage the baffle plate 31 over time and affect its service life.

[0142] In some possible implementations, refer to Figure 2 The baffle demister 20 includes a level gauge (not shown in the figure), and the steam washing circulation pump 50 includes a drain pipe 52. The level gauge is electrically connected to the drain pipe 52 and the demister water tank 40, respectively. The level gauge is used to detect the liquid mist level in the demister water tank 40. The drain pipe 52 is activated when the liquid mist level is higher than the middle position of the demister water tank 40, and closed when the liquid mist level is lower than the set height.

[0143] The falling film demisting and gas scrubbing device also includes a water supply valve 70. The level gauge is electrically connected to the water supply valve 70 and the external acid pump 200. The demister water tank 40 is connected to the water supply valve 70 and the external acid pump 200. The water supply valve 70 is used to start the water supply valve 70 and the external acid pump 200 when the liquid mist height is lower than the set height.

[0144] Using the above technical solution, before the secondary steam enters the spray scrubber 12, condensate needs to be added to the demister water tank 40 to the normal level (the normal level is, for example, the height of the condensate is one-third of the height of the demister water tank 40). Then, the acid pump 200 is started to add dilute sulfuric acid to the set pH value (for example, pH value 4-5), and then the spray scrubber 12 is started. If the pH value is too low, it will easily corrode the demister water tank 40; if the pH value is too high, the condensate in the demister water tank 40 will be alkaline and will lose its function of absorbing ammonia.

[0145] During the operation of the spray scrubber 12, if the liquid mist level is higher than the middle position of the demister water tank 40, the drain pipe 52 will be activated to remove the liquid mist. If the drain pipe 52 is not activated to remove the liquid mist, the excessive liquid mist that accumulates may return to the first inner cavity 211, that is, back into the secondary steam, causing the secondary and tertiary mist separations to fail. Therefore, a level gauge is installed to detect the liquid mist level in the demister water tank 40 so that the drain pipe 52 can be activated in time to remove excess liquid mist from the demister water tank 40.

[0146] When the liquid mist height is lower than the set height (for example, when the liquid mist height is one-fifth of the height of the demister water tank 40), the drain pipe 52 is closed, and the water supply valve 70 and the acid pump 200 are started respectively, so that the condensate in the demister water tank 40 returns to the normal liquid level and the pH value returns to the set value.

[0147] It should be noted that the embodiments of this application do not impose specific limitations on the normal liquid level. For example, in other possible implementations, the normal liquid level can be one-half, one-quarter, etc., of the height of the condensate water tank 40, depending on the specific site conditions. Similarly, the embodiments of this application do not impose specific limitations on the set height. For example, in other possible implementations, the set height can be one-quarter, one-sixth, etc., of the height of the condensate water tank 40, depending on the specific site conditions.

[0148] In some possible implementations, refer to Figure 2 The folding plate demister 20 includes a pH meter (not shown in the figure). The pH meter is electrically connected to the drain pipe 52. The pH meter is used to detect the pH value of the liquid foam in the demister water tank 40. The drain pipe 52 is activated when the pH value is greater than or equal to the set value.

[0149] Using the above technical solution, if the pH is too high, the condensate in the demister water tank 40 will become alkaline and lose its ability to absorb ammonia. Therefore, when the pH value of the liquid mist in the demister water tank 40 is greater than or equal to the set value (the set value is, for example, pH=6), the drain pipe 52 needs to be activated to discharge the liquid mist in the demister water tank 40, making room for subsequent condensate and dilute sulfuric acid to re-enter.

[0150] It should be noted that the pH value is not specifically limited in the embodiments of this application. For example, in other possible implementations, the pH value can be 5.5, 6.5, etc., and the pH value is determined by the specific conditions on site.

[0151] Next, the working principle of the falling film demisting and gas washing device in Example 2 will be explained in detail.

[0152] refer to Figure 2 , Figures 4 to 8 Before starting the falling film demisting scrubbing device, first add condensate to the demister water tank 40 to the normal liquid level (the normal liquid level is, for example, the height of the condensate is one-third of the height of the demister water tank 40), then start the acid pump 200 to add dilute sulfuric acid to the set pH value, and then start the spray scrubbing device 12.

[0153] Secondary steam enters the spray scrubber 12 from the external falling film evaporator 100. After being sprayed by acid-containing water from the spray head 122, it absorbs ammonia (i.e., spray scrubbing gas), achieving primary mist separation. Liquid mist and spray water containing acid and ammonia reacting together flow downwards by gravity, first impacting the liquid collection element 60, and then entering the demister water tank 40. The secondary steam after primary mist separation enters the first inner cavity 211 of the baffle demister 20.

[0154] The secondary steam entering the first inner cavity 211 first passes through the "trumpet-shaped" grid distribution plate 22, and spreads along the first surface 2211, the second surface 2221, the third surface 2231 and the fourth surface 2241 towards the demister section 30, ensuring that the secondary steam evenly fills the first inner cavity 211.

[0155] Subsequently, the secondary steam passes through two demister sections 30 to achieve secondary and tertiary mist separation. When the secondary steam passes through the peak 311 of the baffle 31 in the demister section 30, the liquid droplets collide with the hook 322 of the collecting hook 32 corresponding to the peak 311, and are thus captured by the hook 322. Then, under the action of gravity, the liquid droplets captured by the collecting hook 32 flow downward along the baffle 31 and finally flow into the demister water tank 40. The secondary steam after the tertiary mist separation flows into the steam compressor 400.

[0156] During the operation of the falling film demister scrubbing device, the level gauge detects the liquid mist height in the demister water tank 40. When the liquid mist height is higher than the middle position of the demister water tank 40, the drain pipe 52 is activated to remove the liquid mist. When the liquid mist height is lower than the set height, the drain pipe 52 is closed, and the water supply valve 70 and the acid pump 200 are activated respectively, so that the condensate in the demister water tank 40 returns to the normal level and the pH value returns to the set value.

[0157] Example 3

[0158] Next, we will introduce the falling film demister gas washing device used to handle the secondary steam condition with multiple liquid droplets, namely Example 3.

[0159] In some possible implementations, refer to Figure 3 , Figure 4 and Figure 8The steam treatment unit 10 includes a spray scrubber 12, and the falling film demisting scrubber includes a steam washing circulation pump 50. The steam washing circulation pump 50 is connected to the spray scrubber 12, and one end of the first inner cavity 211 is connected to the spray scrubber 12.

[0160] The spray scrubber 12 includes a second inner cavity 121 and three spray heads 122. The three spray heads 122 are located in the second inner cavity 121, which is connected to the first inner cavity 211. The three spray heads 122 are spaced apart along a second direction Y. The scrubbing steam circulation pump 50 includes a scrubbing steam pipe 51, and the three spray heads 122 are respectively connected to the scrubbing steam pipe 51. The orientation of the three spray heads 122 is the same as the flow direction of the secondary steam from the outside. The demister water tank 40 is connected to both the second inner cavity 121 and the first inner cavity 211. The demister water tank 40 is used to collect the liquid mist separated from the secondary steam flowing through the second inner cavity 121 and the first inner cavity 211.

[0161] Using the above technical solution, when encountering materials with high foaming properties, the secondary steam may contain a particularly large amount of mist. Therefore, a spray scrubber 12 and a steam circulation pump 50 are installed. Secondary steam enters the spray scrubber 12 from the external falling film evaporator 100. After being sprayed by cold water from the spray head 122 (i.e., spray scrubbing), most of the liquid mist is carried away by the spray water, achieving primary mist separation. The liquid mist and spray water flow downwards into the demister water tank 40. The secondary steam after primary mist separation enters the first inner cavity 211 of the baffle demister 20. Secondary mist separation and tertiary mist separation are achieved in the first inner cavity 211, and the flowing liquid mist is collected by the demister water tank 40.

[0162] It should be noted that the number of spray heads 122 is not specifically limited in this application embodiment. For example, in other possible implementations, the number of spray heads 122 may be four, five, etc.

[0163] In some possible implementations, refer to Figure 3 , Figure 4 and Figure 8 The falling film demisting and gas washing device also includes a liquid collection component 60, which is connected to the first inner cavity 211, the second inner cavity 121 and the demister water tank 40 respectively, and the liquid collection component 60 is horizontally aligned with the baffle demister 20.

[0164] Using the above technical solution, since the secondary steam after spray scrubbing will make a 90° turn before entering the baffle demister 20, most of the spray water will impact the liquid collecting element 60 due to inertia. If there were no liquid collecting element 60, the spray water would directly impact the baffle plate 31 inside the baffle demister 20. Over time, this would damage the baffle plate 31 and affect its service life.

[0165] In some possible implementations, refer to Figure 3 The baffle demister 20 includes a level gauge (not shown) and a conductivity meter (not shown). The steam washing circulation pump 50 includes a drain pipe 52. The level gauge is electrically connected to the drain pipe 52 and the demister water tank 40. The level gauge is used to detect the liquid mist level in the demister water tank 40. The drain pipe 52 is activated when the liquid mist level is higher than the middle position of the demister water tank 40, and closed when the liquid mist level is lower than the set level. The conductivity meter is used to detect the conductivity value of the liquid mist in the demister water tank 40. The drain pipe 52 is activated when the conductivity value is higher than the set value, and closed when the liquid mist level is lower than the set level.

[0166] The falling film demister gas scrubbing device also includes a water supply valve 70, which is electrically connected to the level gauge and connected to the demister water tank 40. The water supply valve 70 is activated when the liquid mist height is lower than the set height.

[0167] Using the above technical solution, before the secondary steam enters the spray scrubber 12, condensate needs to be added to the demister water tank 40 to the normal liquid level (the normal liquid level is, for example, the height of the condensate is one-third of the height of the demister water tank 40), and then the spray scrubber 12 is started.

[0168] During the operation of the spray scrubber 12, if the liquid droplet height is higher than the middle position of the demister water tank 40, or if the conductivity of the liquid droplets in the demister water tank 40 is higher than a set value (this set value could be, for example, 5000 μs / cm), the drain pipe 52 will be activated to remove the liquid droplets. If the drain pipe 52 is not activated to remove the liquid droplets, excessive liquid droplets may accumulate and return to the first inner cavity 211, i.e., back into the secondary steam, causing secondary and tertiary mist separation to fail. Therefore, a level gauge is installed to detect the liquid droplet height in the demister water tank 40 so that the drain pipe 52 can be activated in a timely manner to remove excess liquid droplets from the demister water tank 40.

[0169] When the liquid mist height is lower than the set height (for example, when the liquid mist height is one-fifth of the height of the demister water tank 40), the drain pipe 52 is closed and the water supply valve 70 is activated, so that the condensate in the demister water tank 40 returns to the normal liquid level.

[0170] It should be noted that the embodiments of this application do not impose specific limitations on the normal liquid level. For example, in other possible embodiments, the normal liquid level can be half, a quarter, or so on, with the height of the condensate water occupying the height of the demister water tank 40. The normal liquid level is determined by the specific site conditions. Similarly, the embodiments of this application do not impose specific limitations on the set height. For example, in other possible embodiments, the set height can be a quarter, a sixth, or so on, with the liquid level occupying the height of the demister water tank 40. The set height is determined by the specific site conditions. Furthermore, the embodiments of this application do not impose specific limitations on the set value of the conductivity. For example, in other possible embodiments, the set value of the conductivity can be 4500 μs / cm, 4700 μs / cm, or so on. The set value of the conductivity is determined by the specific site conditions.

[0171] Next, the working principle of the falling film demisting and gas washing device in Example 3 will be explained in detail.

[0172] refer to Figure 3 , Figures 4 to 8 Before starting the falling film demisting scrubbing device, first add condensate to the demister water tank 40 to the normal level (the normal level is, for example, the height of the condensate is one-third of the height of the demister water tank 40), and then start the spray scrubbing device 12.

[0173] Secondary steam enters the spray scrubber 12 from the external falling film evaporator 100. After being sprayed by cold water from the spray head 122 (i.e., spray scrubbing), most of the liquid droplets are carried away by the spray water, achieving primary mist separation. The spray water flows downwards by gravity, first impacting the liquid collection element 60, and then entering the demister water tank 40. The secondary steam after primary mist separation enters the first inner cavity 211 of the baffle demister 20.

[0174] The secondary steam entering the first inner cavity 211 first passes through the "trumpet-shaped" grid distribution plate 22, and spreads along the first surface 2211, the second surface 2221, the third surface 2231 and the fourth surface 2241 towards the demister section 30, ensuring that the secondary steam evenly fills the first inner cavity 211.

[0175] Subsequently, the secondary steam passes through two demister sections 30 to achieve secondary and tertiary mist separation. When the secondary steam passes through the peak 311 of the baffle 31 in the demister section 30, the liquid droplets collide with the hook 322 of the collecting hook 32 corresponding to the peak 311, and are thus captured by the hook 322. Then, under the action of gravity, the liquid droplets captured by the collecting hook 32 flow downward along the baffle 31 and finally flow into the demister water tank 40. The secondary steam after the tertiary mist separation flows into the steam compressor 400.

[0176] During the operation of the falling film demister scrubbing device, the level gauge detects the liquid mist height in the demister water tank 40, and the conductivity meter detects the conductivity value of the liquid mist in the demister water tank 40. When the liquid mist height is higher than the middle position of the demister water tank 40, or when the conductivity value of the liquid mist in the demister water tank 40 is higher than a set value (this set value may be, for example, 5000 μs / cm), the drain pipe 52 is activated to remove the liquid mist. When the liquid mist height is lower than the set height, the drain pipe 52 is closed, and the water supply valve 70 is activated, so that the condensate in the demister water tank 40 returns to the normal level.

[0177] When it is necessary to switch operating conditions, such as from conventional operating conditions to ammonia-containing secondary steam operating conditions, simply remove the cyclone separator 11 in Example 1 and replace it with the spray scrubber 12 in Example 2. For example, when switching from multi-liquid-foam secondary steam operating conditions to conventional operating conditions, simply remove the spray scrubber 12 in Example 3 and replace it with the cyclone separator 11 in Example 1.

[0178] While the present invention has been illustrated and described with reference to certain preferred embodiments, those skilled in the art should understand that the above description is a further detailed explanation of the invention in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of the invention to these descriptions. Various changes in form and detail can be made by those skilled in the art, including several simple deductions or substitutions, without departing from the spirit and scope of the invention.

Claims

1. A falling film demisting and gas scrubbing device, characterized in that, The falling film demisting and gas scrubbing device includes: The steam treatment section allows external secondary steam to flow into it from an external falling film evaporator. A folding plate demister, comprising a shell and a grid distribution plate, the shell comprising a first inner cavity, the grid distribution plate being disposed in the first inner cavity along a first direction, one end of the first inner cavity being connected to the steam treatment section, and the other end of the first inner cavity being connected to an external steam compressor; A defoaming section is disposed in the first inner cavity. Along the first direction, the defoaming section is spaced apart from the grid distribution plate. The defoaming section includes multiple baffles and multiple collecting hooks. Along the second direction, the multiple baffles are spaced apart. Each baffle includes multiple peaks. Along the second direction, the peaks of two adjacent baffles have the same orientation. Along the first direction, the peaks of two adjacent baffles have different orientations. Each collecting hook corresponds to each peak. Each collecting hook includes a connecting part and a hook part. The connecting part is connected to the corresponding peak. Along the second direction, the hook parts are spaced apart from the corresponding peaks. In the second direction, the projections of the hook parts and the corresponding peaks coincide. The second direction is perpendicular to the first direction. Secondary steam from the outside can flow sequentially through the falling film evaporator, the steam treatment section, the grid distribution plate, the demister section, and the external steam compressor.

2. The falling film demisting and gas scrubbing device as described in claim 1, characterized in that, The grid-shaped distribution plate includes a first distribution plate and a second distribution plate. The first distribution plate and the second distribution plate extend along the second direction. Along the third direction, the first distribution plate and the second distribution plate are spaced apart. The first distribution plate includes a first surface, and the second distribution plate includes a second surface. Along the third direction, the first surface and the second surface are arranged opposite to each other. The distance between the first surface and the second surface increases towards the defoaming part along the first direction. The third direction is perpendicular to the first direction. The grid-shaped distribution plate includes a third distribution plate and a fourth distribution plate, which extend along the third direction. Along the second direction, the third distribution plate and the fourth distribution plate are spaced apart. The third distribution plate is connected to the first distribution plate and the second distribution plate, and the fourth distribution plate is connected to the first distribution plate and the second distribution plate. The third distribution plate includes a third surface, and the fourth distribution plate includes a fourth surface. Along the second direction, the third surface and the fourth surface are opposite to each other. The distance between the third surface and the fourth surface increases towards the demister along the first direction.

3. The falling film demisting and gas scrubbing device as described in claim 1, characterized in that, Along the second direction, the projection of each hook portion covers the projection of the corresponding peak portion.

4. The falling film demisting and gas scrubbing device as described in claim 1, characterized in that, The steam treatment unit includes a cyclone separator, which includes a central air pipe and a first inner wall. The central air pipe includes a first outer wall, and the first inner wall and the first outer wall define a liquid guiding channel. The falling film demisting and gas washing device includes a demister water tank, which is connected to the liquid guiding channel and the first inner cavity, respectively. The central air pipe is connected to the first inner cavity. The demister water tank is used to collect the liquid mist separated from the secondary steam flowing through the liquid guiding channel and the first inner cavity.

5. The falling film demisting and gas scrubbing device as described in claim 4, characterized in that, The folding plate demister includes a level gauge and a drain pump. The level gauge is electrically connected to the drain pump and the demister water tank, respectively. The level gauge is used to detect the liquid mist height in the demister water tank. The drain pump is started when the liquid mist height is higher than the middle position height of the demister water tank, and shut down when the liquid mist height is lower than the set height.

6. The falling film demisting and gas scrubbing device as described in claim 1, characterized in that, The steam treatment unit includes a spray scrubber, and the falling film demisting scrubber includes a scrubbing steam circulation pump. One end of the scrubbing steam circulation pump is connected to the spray scrubber, and the other end of the scrubbing steam circulation pump is connected to an external acid pump. One end of the first inner cavity is connected to the spray scrubber. The spray scrubber includes a second inner cavity and multiple spray heads. The multiple spray heads are disposed in the second inner cavity, which is connected to the first inner cavity. The multiple spray heads are spaced apart along the second direction. The scrubbing steam circulation pump includes a scrubbing steam pipe. The multiple spray heads are respectively connected to the scrubbing steam pipe. The orientation of the multiple spray heads is the same as the flow direction of the secondary steam from the outside. The falling film demisting scrubbing device includes a demister water tank. The demister water tank is connected to the second inner cavity and the first inner cavity respectively. The demister water tank is used to collect the liquid droplets separated from the secondary steam from the outside as it flows through the second inner cavity and the first inner cavity.

7. The falling film demisting and gas scrubbing device as described in claim 6, characterized in that, The falling film demisting and air washing device also includes a liquid collection component, which is connected to the first inner cavity, the second inner cavity and the demister water tank respectively, and the liquid collection component is horizontally aligned with the baffle demister.

8. The falling film demisting and gas scrubbing device as described in claim 6, characterized in that, The baffle demister includes a level gauge, and the steam washing circulation pump includes a drain pipe. The level gauge is electrically connected to the drain pipe and the demister water tank, respectively. The level gauge is used to detect the liquid mist height in the demister water tank. The drain pipe is activated when the liquid mist height is higher than the middle position height of the demister water tank, and closed when the liquid mist height is lower than the set height. The falling film demisting and gas washing device also includes a water supply valve. The level gauge is electrically connected to the water supply valve and an external acid pump, respectively. The demister water tank is connected to the water supply valve and an external acid pump, respectively. The water supply valve is used to start the water supply valve and the external acid pump when the liquid mist height is lower than the set height.

9. The falling film demisting and gas scrubbing device as described in claim 6, characterized in that, The folding plate demister includes a pH meter, which is electrically connected to a drain pipe. The pH meter is used to detect the pH value of the liquid foam in the demister's water tank. The drain pipe is activated when the pH value is greater than or equal to a set value.

10. The falling film demisting and gas scrubbing device as described in claim 1, characterized in that, The steam treatment unit includes a spray scrubber, and the falling film demisting scrubber includes a steam washing circulation pump. The steam washing circulation pump is connected to the spray scrubber, and one end of the first inner cavity is connected to the spray scrubber. The spray scrubber includes a second inner cavity and multiple spray heads. The multiple spray heads are disposed in the second inner cavity, which is connected to the first inner cavity. The multiple spray heads are spaced apart along the second direction. The scrubbing steam circulation pump includes a scrubbing steam pipe. The multiple spray heads are respectively connected to the scrubbing steam pipe. The orientation of the multiple spray heads is the same as the flow direction of the secondary steam from the outside. The falling film demisting scrubbing device includes a demister water tank. The demister water tank is connected to the second inner cavity and the first inner cavity respectively. The demister water tank is used to collect the liquid droplets separated from the secondary steam from the outside as it flows through the second inner cavity and the first inner cavity.

11. The falling film demisting and gas scrubbing device as described in claim 10, characterized in that, The falling film demisting and air washing device also includes a liquid collection component, which is connected to the first inner cavity, the second inner cavity and the demister water tank respectively, and the liquid collection component is horizontally aligned with the baffle demister.

12. The falling film demisting and gas scrubbing device as described in claim 10, characterized in that, The baffle demister includes a level gauge and a conductivity meter. The steam washing circulation pump includes a drain pipe. The level gauge is electrically connected to the drain pipe and the demister water tank. The level gauge is used to detect the liquid mist height in the demister water tank. The drain pipe is activated when the liquid mist height is higher than the middle position of the demister water tank. The conductivity meter is used to detect the conductivity value of the liquid mist in the demister water tank. The drain pipe is activated when the conductivity value is higher than a set value and closed when the liquid mist height is lower than a set height. The falling film demisting and gas washing device also includes a water supply valve, which is electrically connected to the level gauge and connected to the demister water tank. The water supply valve is activated when the liquid mist height is lower than the set height.

13. The falling film demisting and gas scrubbing device as described in claim 1, characterized in that, The baffle demister includes a spray section, which includes a first water pipe and a nozzle. One end of the first water pipe is connected to an external water pump, and the other end of the first water pipe is connected to the nozzle. The nozzle is located in the first inner cavity and is positioned towards the plurality of baffles along the first direction.

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