Filtering purification device, system and method

Abstract

The present application relates to the technical field of iodine adsorber, and discloses a filtering and purifying device, system and method.The filtering and purifying device comprises a box body and an iodine adsorption filter element, the box body is arranged in a pit, and comprises an air inlet and an air outlet; the iodine adsorption filter element is arranged in the box body, has a first air inlet side close to the air inlet and a first air outlet side close to the air outlet; the iodine adsorption filter element comprises at least one layer of hydrophobic modified activated carbon fiber layer, and the activated carbon fiber layer is attached with triethylenediamine and / or potassium iodide.The activated carbon fiber layer and the pit make the filtering and purifying device suitable for adopting a smothering fire extinguishing mode of closing the air inlet and the air outlet, thereby avoiding the danger that may be caused by the water-based fire extinguishing measure in a nuclear fuel processing site with critical risk; therefore, the filtering and purifying device helps to improve the applicable scene of the iodine nuclide adsorption mode.

Description

Technical Field

[0001] This invention relates to the field of iodine adsorbent technology, specifically to filtration and purification devices, systems, and methods. Background Technology

[0002] Nuclear power facilities and nuclear fuel cycle production facilities generate highly radioactive aerosols and iodine nuclides (including elemental iodine and organic iodine). It is necessary to set up filtration, purification and adsorption measures to maximize the capture of radioactive aerosols and iodine nuclides, minimize the emission of harmful substances, and prevent the spread and disorderly emission of radioactive pollution.

[0003] In related technologies, aerosols and iodine nuclides are treated separately, with iodine nuclides adsorbed using an iodine adsorber. Dry iodine adsorption typically uses impregnated activated carbon particles, but this method has limitations.

[0004] On the one hand, the activated carbon particles used for filling have strict requirements on the temperature and humidity of the air being treated, making them unsuitable for treating high-humidity air, and they also have high resistance due to the small volume of air being treated. On the other hand, according to the relevant requirements of the fire protection design code for nuclear power plants, the iodine adsorbers of this technology need to be equipped with water-based fire extinguishing measures such as spraying and flooding, making them unsuitable for nuclear fuel processing sites with critical risks, thus limiting their applicability. Summary of the Invention

[0005] In view of this, the present invention provides a filtration and purification device, system and method to solve the problem of limited applicability of iodine radionuclide adsorption.

[0006] In a first aspect, the present invention provides a filtration and purification device, comprising a housing and an iodine adsorption filter element. The housing is for installation in a pit and includes an air inlet and an air outlet. The iodine adsorption filter element is disposed in the housing and has a first air inlet side near the air inlet and a first air outlet side near the air outlet. The iodine adsorption filter element includes at least one layer of hydrophobically modified activated carbon fiber, wherein the activated carbon fiber layer is coated with triethylenediamine and / or potassium iodide.

[0007] Beneficial effects: Airflow enters the filtration and purification device through the inlet, passes through the iodine adsorption filter element from the first inlet side to the first outlet side, and then exits from the outlet. The filtration and purification device uses an activated carbon fiber layer as the filter adsorption material, which can adsorb elemental iodine through physical means. The activated carbon fiber layer is coated with triethylenediamine and / or potassium iodide, which can adsorb organic iodine through chemical reactions, meeting the requirements for adsorbing iodine nuclides. On the one hand, the activated carbon fiber layer is hydrophobically modified, thereby reducing the hygroscopicity of the iodine adsorption filter element, making it suitable for filtering and purifying high-humidity air. On the other hand, the use of activated carbon fiber... Replacing activated carbon particles with carbon fiber layers helps reduce the weight and fire load of the iodine adsorption filter element, thereby reducing the danger in the event of a fire. Furthermore, placing the iodine adsorption filter element in a pit allows the good fire-resistant sealing properties of the ground (usually concrete) and the cover plate (usually carbon steel plate) to be utilized. This makes the filtration and purification device suitable for asphyxiation fire suppression using a closed air inlet and outlet, avoiding the dangers that may arise from using water-based fire suppression measures in nuclear fuel processing sites with critical risks. Therefore, the filtration and purification device helps to expand the applicable scenarios for iodine radionuclide adsorption.

[0008] In one optional embodiment, the iodine adsorption filter element includes multiple layers of activated carbon fiber, the activated carbon fiber layers being stacked on top of each other in the thickness direction, and the activated carbon fiber layers having a folded structure.

[0009] Beneficial effects: The iodine adsorption filter has multiple layers of activated carbon fiber, which can enhance the residence contact time between iodine nuclides and activated carbon fiber layers, improve adsorption efficiency, and the folded structure increases the surface area of ​​the iodine adsorption filter, making it suitable for handling high airflow.

[0010] In an optional embodiment, the housing further includes a first cover plate and a lifting rod. The housing includes a first lifting hole located on top of the iodine adsorption filter element. The first cover plate is used to close or open the first lifting hole, and the lifting rod is detachably connected between the first cover plate and the iodine adsorption filter element.

[0011] Beneficial effects: The iodine adsorption filter element is installed and removed from the first lifting hole by means of hoisting, which facilitates the use and maintenance of the filtration and purification device; the hoisting rod connects the iodine adsorption filter element and the first cover plate together, and the iodine adsorption filter element can be naturally taken out when the first cover plate is opened, making maintenance more convenient.

[0012] In one alternative embodiment, a first drawstring bag is further included, the opening of which is detachably fitted onto the first lifting hole, and the bottom of which is fixed to the iodine adsorption filter element.

[0013] Beneficial effects: During the lifting process, the iodine adsorption filter element passes through the first lifting hole, so that the first bundled bag covers the iodine adsorption filter element. As the iodine adsorption filter element is further lifted, the tension causes the first bundled bag to separate from the first lifting hole and wrap around the bottom of the iodine adsorption filter element for sealing. The first bundled bag can reduce the risk of iodine radionuclide leakage during disassembly.

[0014] In one optional embodiment, the activated carbon fiber layers are connected end to end to form a first cylinder. The iodine adsorption filter element also includes two first end caps, which are respectively disposed at both ends of the first cylinder. The first end cap located at the bottom is provided with a first through hole, and the first end cap located at the bottom is fixedly connected to the bottom of the first drawstring bag.

[0015] Beneficial effect: By staggering the airflow path and the position of the first drawstring bag, the airflow can be prevented from blowing the first drawstring bag apart during operation, thus improving the reliability of the seal.

[0016] In an alternative embodiment, a pre-adsorption filter element is further included, which is disposed within the housing and located upstream of the iodine adsorption filter element, the pre-adsorption filter element being used to filter aerosols.

[0017] Beneficial effects: During operation, the pre-adsorption filter first adsorbs radioactive aerosols, and then the iodine adsorption filter adsorbs iodine nuclides, achieving two-stage filtration in the filtration and purification device. This enriches the function of the filtration and purification device, and the different radioactive substances are enriched on different filter elements, which also facilitates subsequent classification and treatment.

[0018] In one optional embodiment, the air inlet and the air outlet are located at the bottom of the housing, the pre-adsorption filter is disposed at the air inlet, and the iodine adsorption filter is disposed at the air outlet.

[0019] Beneficial effects: By placing the pre-adsorption filter directly at the air inlet and the iodine adsorption filter directly at the air outlet, it is easy to hoist the pre-adsorption filter and the iodine adsorption filter, forming an airflow path through the pre-adsorption filter and the iodine adsorption filter, simplifying the structure of the box, reducing implementation costs and reducing sanitary dead corners of the box.

[0020] In one optional embodiment, the system further includes a first collection pipe and a second collection pipe, which are disposed at the bottom of the housing. The first collection pipe is connected to the air inlet and has a first collection pool at its bottom. The second collection pipe is connected to the air outlet and has a second collection pool at its bottom.

[0021] Beneficial effects: Water droplets or radioactive substances that drip during filtration can be collected in the first and second collection pools, facilitating subsequent cleaning.

[0022] Secondly, the present invention also provides a filtration and purification system, including the filtration and purification device of the present invention and a sealing valve, wherein the sealing valve includes a first sealing valve and a second sealing valve, the first sealing valve and the second sealing valve being respectively disposed at the air inlet and the air outlet.

[0023] Beneficial effects: The filtration and purification system uses the filtration and purification device of the present invention, and therefore has the beneficial effects brought by the filtration and purification device of the present invention, which will not be elaborated here.

[0024] Thirdly, the present invention also provides a filtration and purification method. Using the filtration and purification system of the present invention, the filtration and purification method includes: forming an airflow from the air inlet to the air outlet to adsorb and filter iodine nuclides; monitoring the temperature and / or flue gas concentration inside the chamber in real time; and closing the first sealing valve and the second sealing valve in response to the temperature reaching a first threshold and / or the flue gas concentration reaching a second threshold.

[0025] Beneficial effects: By adopting a pit design and a hydrophobic modified activated carbon fiber layer, the filtration and purification method is suitable for extinguishing fires by asphyxiation, avoiding the dangers that may arise from using water-based fire extinguishing measures in nuclear fuel processing sites with critical risks. Attached Figure Description

[0026] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the structure of a filtration and purification device according to an embodiment of the present invention;

[0028] Figure 2 This is a cross-sectional view of the iodine adsorption filter element according to an embodiment of the present invention;

[0029] Figure 3 This is a top view of the iodine adsorption filter element according to an embodiment of the present invention, in which the first end cap is hidden;

[0030] Figure 4 for Figure 1 A magnified view of a portion of region A in the middle;

[0031] Figure 5 This is a schematic diagram of a filtration and purification system according to an embodiment of the present invention.

[0032] Explanation of reference numerals in the attached figures:

[0033] 1. Filtration and purification device; 101. Box body; 102. Iodine adsorption filter element; 1021. First cylinder; 1022. First end cap; 1023. First sealing element; 1024. First grid; 1031. First cover plate; 1032. Second cover plate; 1033. Shielding plate; 1034. Positioning seat; 1035. Positioning ring; 104. Lifting rod; 1051. First drawstring bag; 1052. Second drawstring bag; 106. Pre-adsorption filter element; 1071. First collection pipe; 1072. Second collection pipe; 201. First sealing valve; 202. Second sealing valve; 203. Third sealing valve; 204. Fourth sealing valve; 205. Fifth sealing valve; 206. Sixth sealing valve; 3. Inlet air filter; 4. Exhaust air filter; 5. Fan; 6. Chimney; 9. Radioactive space. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "a," "an," and "comprising" as used herein may also mean including the plural forms. The terms "comprising," "including," and "having" are inclusive and therefore indicate the presence of the stated features, elements, and / or components, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof.

[0036] Although terms such as "first," "second," etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Furthermore, in the description of this application, unless otherwise expressly specified and limited, the terms "set up" and "connected" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a direct connection or an indirect connection via an intermediate medium. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

[0037] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "end," "length," "inner," "outer," etc. Such spatial relative terms are intended to include different orientations of the mechanism in use or operation, in addition to those depicted in the figure. For example, if the mechanism in the figure is flipped, an element described as "below other elements or features" or "below other elements or features" would subsequently be oriented as "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The mechanism may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0038] Iodine adsorbers are used to adsorb iodine nuclides (including elemental iodine and organic iodine). Iodine adsorbers have two technical routes: wet and dry.

[0039] Among them, wet methods mainly use alkaline solutions such as sodium hydroxide to absorb and treat iodine nuclides, which have problems such as high system resistance and difficulty in treating radioactive wastewater, and are not suitable for ventilation purification.

[0040] Dry adsorption mainly includes two adsorption methods: silver-coated silica gel and impregnated activated carbon particles. Silver-coated silica gel adsorbents are mainly used for high-concentration, low-flow process exhaust gases. However, they have high resistance and require adsorption air temperatures of over 100°C, thus necessitating additional heating measures. Therefore, they are not suitable for air iodine adsorption in the ventilation systems of radioactive buildings in nuclear facilities. Consequently, iodine adsorbers in ventilation systems in related technologies generally use impregnated activated carbon particles. However, the filled activated carbon particles have strict requirements for the temperature and humidity of the air being treated, making them unsuitable for treating high-humidity air.

[0041] Furthermore, according to the relevant requirements of the fire protection design code for nuclear power plants, the iodine adsorbers of this technology must be used in conjunction with water-based fire extinguishing measures such as spraying and flooding, and are not suitable for nuclear fuel processing sites with criticality risks, thus limiting their applicability.

[0042] In addition, activated carbon particles are easily blown by the air and produce scattered carbon powder. The carbon powder escapes and settles in the air duct, which increases the difficulty of cleaning and also brings the risk of radioactive pollution spreading.

[0043] The following is combined with Figures 1 to 5 The following describes embodiments of the present invention.

[0044] Reference Figure 1 , Figure 2 , Figure 3According to an embodiment of the present invention, in one aspect, a filtration and purification device 1 is provided, including a housing 101 and an iodine adsorption filter element 102. The housing 101 is used to be installed in a pit and includes an air inlet and an air outlet. The iodine adsorption filter element 102 is installed inside the housing 101 and has a first air inlet side near the air inlet and a first air outlet side near the air outlet. The iodine adsorption filter element 102 includes at least one layer of hydrophobically modified activated carbon fiber layer, and the activated carbon fiber layer is coated with triethylenediamine and / or potassium iodide.

[0045] In use, the airflow enters the filter purification device 1 from the air inlet, passes through the iodine adsorption filter element 102 from the first air inlet side to the first air outlet side, and then leaves from the air outlet. The filter purification device 1 uses an activated carbon fiber layer as the filter adsorption material, which can adsorb elemental iodine through physical means. The activated carbon fiber layer is attached with triethylenediamine and / or potassium iodide, which can adsorb organic iodine through chemical reaction (reacting with organic iodine to form ammonium salt compounds), thus meeting the requirements for adsorbing iodine nuclides.

[0046] On the one hand, the activated carbon fiber layer is hydrophobically modified, thereby reducing the hygroscopicity of the iodine adsorption filter element 102, making the iodine adsorption filter element 102 suitable for filtering and purifying high humidity air.

[0047] On the other hand, the present invention specifically notes that the reason for using water-based fire extinguishing measures in related technologies for iodine adsorbers is that activated carbon particle iodine adsorbers have a high carbon content, high fire load, and high fire risk. Therefore, the present invention uses an activated carbon fiber layer to replace activated carbon particles, which can increase the contact area per unit mass, help reduce the weight and fire load of the iodine adsorption filter element 102, thereby reducing the danger in the event of a fire. On this basis, the iodine adsorption filter element 102 is further placed in a pit, and the good fireproof sealing properties of the ground (usually concrete) and the cover plate (usually carbon steel plate) are utilized, making the filtration and purification device 1 suitable for using a suffocation fire extinguishing method with closed air inlets and outlets, avoiding the danger that may be caused by using water-based fire extinguishing measures in nuclear fuel processing sites with critical risks.

[0048] In addition, the activated carbon fiber layer is more firmly bonded and is less likely to form scattered carbon powder under the action of airflow, which helps to reduce the risk of radioactive pollution spread.

[0049] Therefore, the filtration and purification device 1 helps to improve the applicable scenarios of iodine radionuclide adsorption.

[0050] It is understood that triethylenediamine and / or potassium iodide can be attached to the activated carbon fiber layer by means of impregnation, spraying, coating, etc., and the present invention does not limit this.

[0051] Furthermore, in some embodiments, the iodine adsorption filter element 102 includes multiple layers of activated carbon fiber, which are stacked together in the thickness direction and have a folded structure. By setting multiple layers of activated carbon fiber, the flow resistance can be increased, and the passage time of the airflow in the iodine adsorption filter element 102 can be extended, thereby providing sufficient reaction time for chemical reactions and improving the adsorption effect of the iodine adsorption filter element 102 on organic iodine. On this basis, a folded structure (i.e., forming serrated or wavy folds) is further designed in the activated carbon fiber layer, thereby increasing the surface area of ​​the activated carbon fiber layer, compensating for the increase in flow resistance caused by the increase in the number of layers, making the iodine adsorption filter element 102 suitable for handling high-volume airflow.

[0052] In some embodiments, the filtration and purification device 1 further includes a first cover plate 1031, and the housing 101 includes a first lifting hole located on top of the iodine adsorption filter element 102. The first cover plate 1031 is used to close or open the first lifting hole. The iodine adsorption filter element 102 is installed and removed from the first lifting hole by means of lifting, thereby facilitating the use and maintenance of the filtration and purification device 1.

[0053] Optionally, in some embodiments, the filtration and purification device 1 further includes a lifting rod 104, which is detachably connected between the first cover plate 1031 and the iodine adsorption filter element 102. The lifting rod 104 connects the iodine adsorption filter element 102 and the first cover plate 1031 together. During installation, the iodine adsorption filter element 102 can be connected to the first cover plate 1031 first through the lifting rod 104, and then the first cover plate 1031 can be lowered. When the first cover plate 1031 is lowered, the iodine adsorption filter element 102 is also placed in place at the same time. During disassembly and replacement, the iodine adsorption filter element 102 can be naturally taken out of the housing 101 when the first cover plate 1031 is opened, making maintenance more convenient.

[0054] It is understood that, in order to shield radioactivity, the first cover plate 1031 can be made of a material with shielding capabilities, such as cast iron or carbon steel. Furthermore, in some embodiments, the filtration and purification device 1 also includes a shielding plate 1033, which covers the pit to seal the pit and cover the box 101. The shielding plate 1033 is provided with a first step hole, and the first cover plate 1031 is placed on the first step hole.

[0055] It should be noted that the used iodine adsorption filter cartridge 102 is enriched with a large amount of iodine nuclides. If it is subjected to vibration or impact during the replacement process, some of the iodine nuclides may be released back into the environment, causing radioactive diffusion.

[0056] Therefore, in some embodiments, the filtration and purification device 1 further includes a first drawstring bag 1051, the opening of which is detachably fitted onto the first lifting hole, and the bottom of which is fixed to the iodine adsorption filter element 102.

[0057] Specifically, during installation, first connect the lifting rod 104, the iodine adsorption filter element 102, and the bottom of the first drawstring bag 1051 together; then lift and lower the iodine adsorption filter element 102 into the first lifting hole; when the iodine adsorption filter element 102 has descended to a suitable operating position (for example, when the top of the iodine adsorption filter element 102 is level with the height of the first lifting hole), pause the descent, and place the opening of the first drawstring bag 1051 over the first lifting hole to ensure that the first drawstring bag 1051 fully covers the first lifting hole; finally, continue the descent to place the iodine adsorption filter element 102 and the first cover plate 1031 into place.

[0058] During the hoisting process, the iodine adsorption filter element 102 passes through the first hoisting hole, so that the first bundled bag 1051 covers the iodine adsorption filter element 102. As the iodine adsorption filter element 102 is further lifted, the pulling force causes the first bundled bag 1051 to separate from the first hoisting hole and wrap around the bottom of the iodine adsorption filter element 102 for sealing. After sealing, the iodine adsorption filter element 102 and the first bundled bag 1051 are removed from the hoisting rod 104 as a whole. The first bundled bag 1051 can reduce the risk of iodine radionuclide leakage during the disassembly process.

[0059] In some embodiments, the activated carbon fiber layers are connected end to end to form a first cylindrical body 1021. The iodine adsorption filter element 102 also includes two first end caps 1022, which are respectively disposed at both ends of the first cylindrical body 1021. The first end cap 1022 located at the bottom is provided with a first through hole, and the first end cap 1022 located at the bottom is fixedly connected to the bottom of the first drawstring bag 1051. By staggering the flow path of the airflow and the position of the first drawstring bag 1051, it is possible to prevent the airflow from blowing through the first drawstring bag 1051 during operation, thereby improving the reliability of the seal.

[0060] Optionally, the iodine adsorption filter element 102 has the following external dimensions: The thickness of the first cylinder 1021 is between 70mm and 100mm, and it is hydrophobically modified by high-pressure atomization spraying or impregnation with 5% to 15% concentration of TEDA (triethylenediamine) or potassium iodide. It is suitable for air volumes ranging from 850 to 3000 m³ / h. 3 / h.

[0061] Reference Figure 3In some embodiments, the iodine adsorption filter element 102 further includes two first grids 1024, which are connected between two first end caps 1022. The two first grids 1024 are located on the inner and outer sides of the first cylinder 1021, respectively, thereby constraining the shape of the first cylinder 1021 and preventing the first cylinder 1021 from deforming under the action of airflow.

[0062] In some embodiments, the iodine adsorption filter element 102 further includes a first sealing element 1023, which is disposed on a first end cap 1022 having a first through hole. The first sealing element 1023 is used to seal the gap between the iodine adsorption filter element 102 and the housing 101 to prevent unfiltered gas from leaking out.

[0063] To further restrict the flow field, in some embodiments, a partition can be provided inside the housing 101. The partition is horizontally arranged and has a first mating hole. In operation, the first mating hole can cooperate with the first end cover 1022 to divide the housing 101 into an upper space and a lower space. The airflow is restricted to the lower space, thereby further reducing the risk of the airflow breaking the first drawstring bag 1051.

[0064] In some embodiments, the filtration and purification device 1 further includes a pre-adsorption filter element 106, which is disposed within the housing 101 and located upstream of the iodine adsorption filter element 102. The pre-adsorption filter element 106 is used to filter aerosols. During operation, the pre-adsorption filter element 106 first adsorbs radioactive aerosols, and then the iodine adsorption filter element 102 adsorbs iodine nuclides, achieving two-stage filtration in the filtration and purification device 1. This enriches the functionality of the filtration and purification device 1, and the accumulation of different radioactive substances on different filter elements facilitates subsequent classification and processing. The pre-adsorption filter element 106 and the iodine adsorption filter element 102 operate independently, allowing each to perform its function and be replaced separately. When the cumulative radioactive dose of either element reaches the replacement standard, it is replaced individually, avoiding simultaneous replacement.

[0065] It is understood that the pre-adsorption filter element 106 can use conventional aerosol adsorption filter elements in related technologies. This invention does not limit this. The design of the pre-adsorption filter element 106 and its related structures can refer to the iodine adsorption filter element 102.

[0066] For example, in some embodiments, the pre-adsorption filter element 106 includes a second cylinder body, which is formed by connecting fiber paper end to end. The pre-adsorption filter element 106 also includes two second end caps and two second grids. The two second end caps are respectively disposed at both ends of the second cylinder body. The second end cap located at the bottom is provided with a second through hole. The second grids are connected between the two second end caps. The two second grids are respectively located on the inner and outer sides of the second cylinder body, thereby constraining the shape of the second cylinder body.

[0067] Correspondingly, the filtration and purification device 1 also includes a second cover plate 1032 and a second drawstring bag 1052. The housing 101 includes a second lifting hole located on top of the pre-adsorption filter element 106. The second cover plate 1032 is detachably connected to the pre-adsorption filter element 106 via another lifting rod 104. The opening of the second drawstring bag 1052 is detachably fitted onto the second lifting hole, and the bottom of the second drawstring bag 1052 is fixed to the pre-adsorption filter element 106. A second stepped hole is provided on the shielding plate 1033, and the second cover plate 1032 is placed on the second stepped hole.

[0068] By introducing the second cover plate 1032 and the second drawstring bag 1052, the pre-adsorption filter element 106 can also be easily installed and disassembled by hoisting, reducing the risk of radioactive aerosols escaping into the environment during disassembly. Furthermore, the pre-adsorption filter element 106 can also be hydrophobically modified to meet the filtration requirements of high-humidity air.

[0069] It is understandable that the openings of the first drawstring bag 1051 / second drawstring bag 1052 can be fitted onto the first lifting hole / second lifting hole in a similar manner. "Fitting onto the first lifting hole / second lifting hole" specifically means fitting onto the structure (such as the box 101, shielding plate 1033, etc.) around the first lifting hole / second lifting hole so that the opening of the bag covers the first lifting hole / second lifting hole.

[0070] Taking the second drawstring bag 1052 as an example, refer to Figure 4 In some embodiments, the filtration and purification device 1 further includes a positioning seat 1034 and a positioning ring 1035. The positioning seat 1034 is annular and is inserted into the second step hole, with its top protruding from the bottom of the second step hole. The outer periphery of the positioning seat 1034 is provided with an annular groove, and the positioning ring 1035 is used to be elastically and detachably embedded in the groove.

[0071] When installing the second drawstring bag 1052, fold the opening of the second drawstring bag 1052 outwards and place it on the positioning seat 1034. Then, use the positioning ring 1035 to cover and press the second drawstring bag 1052 to secure it. When removing the pre-adsorption filter element 106, the second drawstring bag 1052 is pulled away from the positioning ring 1035 by the traction force of the pre-adsorption filter element 106, so that the bag opening can be tightened.

[0072] The first drawstring bag 1051 can also be set using the positioning seat 1034 and the positioning ring 1035, which will not be described in detail here.

[0073] In some embodiments, the air inlet and air outlet are located at the bottom of the housing 101, the pre-adsorption filter 106 is disposed at the air inlet, and the iodine adsorption filter 102 is disposed at the air outlet.

[0074] The pre-adsorption filter element 106 and the iodine adsorption filter element 102 are lowered through the first and second lifting holes by means of hoisting. By placing the air inlet and air outlet at the bottom, the lowered pre-adsorption filter element 106 and the iodine adsorption filter element 102 can be conveniently and directly placed at the air inlet and air outlet, which simplifies the installation method of the pre-adsorption filter element 106 and the iodine adsorption filter element 102.

[0075] Understandably, referring to Figure 1 and Figure 2 When the air inlet and outlet are located at the bottom of the housing 101, the airflow first enters the inner side of the pre-adsorption filter 106 from bottom to top, then passes through the pre-adsorption filter 106 from the inside to the outside to filter aerosols, then passes through the iodine adsorption filter 102 from the outside to the inside to filter iodine nuclides, and finally leaves from the outlet from top to bottom.

[0076] In some embodiments, the filtration and purification device 1 further includes a first collection pipe 1071, which is disposed at the bottom of the housing 101 and connected to an air inlet. A first collection pool is disposed at the bottom of the first collection pipe 1071. Condensed liquid dripping from the pre-adsorption filter element 106 will collect in the first collection pool to facilitate liquid collection and treatment.

[0077] Optionally, the first collection pipe 1071 may include a first port and a second port. The first port is used to connect with the upstream, and the second port is used to connect with the air inlet. The diameter of the first port is less than one-quarter of the diameter of the first collection pipe 1071. When the gas enters the first collection pipe 1071 from the first port, it expands and cools down, which helps to promote the condensation of moisture in the gas, making the filter purification device 1 more suitable for dealing with high humidity air.

[0078] Similarly, in some embodiments, the filtration and purification device 1 further includes a second collection pipe 1072, which is disposed at the bottom of the housing 101, connected to the air outlet, and a second collection pool is disposed at the bottom of the second collection pipe 1072.

[0079] Reference Figure 5 Secondly, the present invention also provides a filtration and purification system, including the filtration and purification device 1 of the present invention and a shut-off valve, the shut-off valve including a first shut-off valve 201 and a second shut-off valve 202, the first shut-off valve 201 and the second shut-off valve 202 being respectively disposed at the air inlet and the air outlet.

[0080] In the event of a fire, the filtration and purification system can close the first sealing valve 201 and the second sealing valve 202, thus sealing the fire source within the pit and extinguishing the fire by suffocation. The filtration and purification system uses the filtration and purification device 1 of this invention, and therefore possesses the beneficial effects of the filtration and purification device 1 of this invention, which will not be elaborated further here.

[0081] Optionally, the first shut-off valve 201 and the second shut-off valve 202 are fire-resistant valves to meet fire protection requirements.

[0082] Additionally, refer to Figure 5 The filtration and purification device 1 can be directly connected to the exit of the radioactive space 9 (box, room, etc.), that is, a pit and the filtration and purification device 1 can be set up nearby next to the radioactive space 9, so as to complete the adsorption and filtration of iodine nuclides as early as possible and avoid the deposition of iodine nuclides in the air duct.

[0083] In some embodiments, the filtration and purification system further includes a fan 5, an inlet filter 3, an exhaust filter 4, and a chimney 6. The inlet filter 3 is located upstream of the radioactive space 9 and is used to supply the radioactive space 9 with air that meets the requirements. The exhaust filter 4, the fan 5, and the chimney 6 are sequentially located downstream of the filtration and purification device 1. The exhaust filter 4 is used to filter the non-radioactive part of the air so that the air meets the emission standards. The fan 5 is used to generate airflow, and the chimney 6 is used to exhaust the air.

[0084] In some embodiments, the filtration and purification system further includes a third airtight valve 203, a fourth airtight valve 204, a fifth airtight valve 205, and a sixth airtight valve 206. The third airtight valve 203 is disposed between the inlet air filter 3 and the radioactive space 9; the fourth airtight valve 204 is disposed between the filtration and purification device 1 and the exhaust air filter 4, and is located downstream of the second airtight valve 202; the fifth airtight valve 205 is disposed between the exhaust air filter 4 and the fan 5; and the sixth airtight valve 206 is disposed between the fan 5 and the chimney 6. In the event of a fire, the third airtight valve 203, the fourth airtight valve 204, the fifth airtight valve 205, and the sixth airtight valve 206 can also be closed, further reducing the risk of fire spread.

[0085] Optionally, in some embodiments, the filtration and purification device 1 is configured with one in operation and one on standby, or vice versa. That is, multiple filtration and purification devices 1 are connected in parallel in the filtration and purification system, and each filtration and purification device 1 is equipped with a first sealing valve 201 and a second sealing valve 202. At least one filtration and purification device 1 serves as a standby filtration and purification device 1, closing its corresponding first sealing valve 201 and second sealing valve 202 during normal operation and reopening them in case of fire, ensuring that the filtration and purification system maintains a certain level of ventilation and purification capacity even during a fire. The standby filtration and purification device 1 can also be activated to provide ventilation and purification capacity during maintenance or replacement of the normally operating filtration and purification device 1.

[0086] Thirdly, the present invention also provides a filtration and purification method, which uses the filtration and purification system of the present invention and includes the following steps:

[0087] Step S110: An airflow is formed from the air inlet to the air outlet to adsorb and filter iodine nuclides.

[0088] At this time, the first sealing valve 201 and the second sealing valve 202 are in the open state.

[0089] Step S120: Monitor the temperature and / or flue gas concentration inside the enclosure 101 in real time.

[0090] Temperature and flue gas concentration can be monitored by equipping appropriate sensors. Temperature sensors are generally installed at the air inlet, while flue gas sensors are generally installed at the air outlet.

[0091] Step S130: In response to the temperature reaching the first threshold and / or the flue gas concentration reaching the second threshold, close the first shut-off valve 201 and the second shut-off valve 202.

[0092] By employing a pit design and a hydrophobic modified activated carbon fiber layer, the filtration and purification method is suitable for extinguishing fires by asphyxiation, avoiding the dangers that may arise from using water-based fire extinguishing measures in nuclear fuel processing sites with critical risks.

[0093] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A filtration and purification device, characterized in that, include: The enclosure (101) is used to be installed in the pit and includes an air inlet and an air outlet; An iodine adsorption filter element (102) is disposed inside the housing (101) and has a first air inlet side near the air inlet and a first air outlet side near the air outlet. The iodine adsorption filter element (102) includes at least one layer of hydrophobically modified activated carbon fiber, and the activated carbon fiber layer is coated with triethylenediamine and / or potassium iodide. The filtration and purification device further includes a first cover plate (1031) and a lifting rod (104). The housing (101) includes a first lifting hole, which is located on the top of the iodine adsorption filter element (102). The first cover plate (1031) is used to close or open the first lifting hole. The lifting rod (104) is detachably connected between the first cover plate (1031) and the iodine adsorption filter element (102). The filtration and purification device also includes a first drawstring bag (1051), the opening of which is detachably fitted onto the first lifting hole, and the bottom of which is fixed to the iodine adsorption filter element (102). The activated carbon fiber layers are connected end to end to form a first cylinder (1021). The iodine adsorption filter element (102) also includes two first end caps (1022). The two first end caps (1022) are respectively disposed at both ends of the first cylinder (1021). The first end cap (1022) at the bottom is provided with a first through hole. The first end cap (1022) at the bottom is fixedly connected to the bottom of the first drawstring bag (1051).

2. The filtration and purification device according to claim 1, characterized in that, The iodine adsorption filter element (102) includes multiple layers of activated carbon fiber, which are stacked on top of each other in the thickness direction and have a folded structure.

3. The filtration and purification device according to claim 1, characterized in that, It also includes a pre-adsorption filter element (106), which is disposed inside the housing (101) and located upstream of the iodine adsorption filter element (102), and the pre-adsorption filter element (106) is used to filter aerosols.

4. The filtration and purification device according to claim 3, characterized in that, The air inlet and the air outlet are located at the bottom of the housing (101), the pre-adsorption filter element (106) is disposed at the air inlet, and the iodine adsorption filter element (102) is disposed at the air outlet.

5. The filtration and purification device according to claim 4, characterized in that, It also includes a first collection pipe (1071) and a second collection pipe (1072), the first collection pipe (1071) and the second collection pipe (1072) are disposed at the bottom of the housing (101), the first collection pipe (1071) is connected to the air inlet, and a first collection pool is disposed at the bottom of the first collection pipe (1071), the second collection pipe (1072) is connected to the air outlet, and a second collection pool is disposed at the bottom of the second collection pipe (1072).

6. A filtration and purification system, characterized in that, include: The filtration and purification device (1) according to any one of claims 1 to 5; The airtight valve includes a first airtight valve (201) and a second airtight valve (202), which are respectively disposed at the air inlet and the air outlet.

7. A filtration and purification method, characterized in that, The filtration and purification method uses the filtration and purification system of claim 6, and the filtration and purification method includes: An airflow is formed from the air inlet to the air outlet to adsorb and filter iodine nuclides. Real-time monitoring of temperature and / or flue gas concentration inside the enclosure (101); In response to the temperature reaching a first threshold and / or the flue gas concentration reaching a second threshold, the first sealing valve (201) and the second sealing valve (202) are closed.

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