Filtering and discharging device for offshore nuclear power system

Abstract

The invention discloses a filtering and discharging device for an offshore nuclear power system, and belongs to the technical field of offshore nuclear power systems. According to the filtering and discharging device for the offshore nuclear power system, a horizontal tank body serves as a shell, the horizontal tank body can be installed in a sealed cabin or a compartment on a ship, and the remaining space of the sealed cabin or the compartment on the ship can have other purposes; all parts of the filtering and discharging device are easy to install in the horizontal tank body, the whole filtering and discharging device is integrated in the horizontal tank body, the miniaturization and integration requirements of the space of the offshore nuclear power system can be met, and the material and the thickness of the horizontal tank body are designed, so that the cost is reduced. The pressure relief requirement of a reactor cabin containment after a serious accident can be met; besides, through the combined action of the Venturi washing unit, the demisting unit and the metal fiber filtering unit, radioactive aerosol and iodine discharged by the reactor cabin containment during serious accidents can be efficiently filtered, so that the nuclear radiation safety of personnel and the environment is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of offshore nuclear power systems, and in particular relates to a filtering and discharging device for offshore nuclear power systems. Background Art

[0002] As a mobile nuclear facility at sea, the probability and risk of accidents in offshore nuclear power systems are relatively high under complex and changeable operating conditions. Once a serious accident occurs, it will lead to serious consequences such as core meltdown and reactor compartment containment overpressure.

[0003] The reactor containment is an important barrier for the offshore nuclear power system to contain radioactivity after an accident. In order to ensure the integrity of the reactor containment structure after a serious accident, the offshore nuclear power system needs to refer to land-based nuclear power plants to set up a filtering and discharging device, so that the radioactive mixed gas in the reactor containment is quickly discharged to it, ensuring that the pressure of the reactor containment does not exceed its limit; at the same time, during the discharge process, the device can effectively remove aerosols, elemental iodine and organic iodine in the radioactive mixed gas. The purified gas can greatly reduce the impact on personnel and the environment, thereby ensuring the safety of nuclear radiation during the discharge process.

[0004] At present, the containment filter and discharge device of land-based nuclear power plants adopts the technical scheme of sand bed filtration, metal fiber filtration or Venturi washing + metal fiber filtration, but the volume and weight of this type of device are relatively large, and it is not suitable for offshore nuclear power systems. The Chinese patent application with publication number CN108154939A discloses a containment filter and discharge system based on a small-scale reactor on water, which uses the existing sealed cabin or compartment on the ship as the shell of the filter device, integrates the Venturi washing process and the metal fiber filtration process, saves system cost and layout space, but because the shell of the filter and discharge device is a sealed cabin or compartment, and the internal space of the sealed cabin or compartment is relatively large, it is relatively difficult to install components inside the sealed cabin or compartment to form a filter and discharge device, and the sealed cabin or compartment on the ship itself is not used for filtering and discharging, and generally cannot withstand the pressure of the reactor containment to release radioactive gas in a serious accident, and cannot ensure that the environment is not polluted by the radioactive carrier gas. Summary of the invention

[0005] In view of this, the present invention provides a filtering and discharging device for an offshore nuclear power system, which can not only meet the requirements of miniaturization and integration of the offshore nuclear power system space, but also withstand the pressure relief requirements of the reactor compartment containment after a serious accident, and has a highly efficient filtering effect on the radioactive aerosols and iodine released from the reactor compartment containment during a serious accident, so as to ensure the nuclear radiation safety of personnel and the environment.

[0006] The present invention provides a filtering and discharging device for an offshore nuclear power system, which adopts the following technical solutions:

[0007] A filtering and discharging device for an offshore nuclear power system comprises a horizontal pressure vessel, a baffle, a venturi scrubber unit, a demisting unit and a metal fiber filtering unit;

[0008] The horizontal pressure vessel is provided with an air inlet for connecting with a pressure relief discharge channel in the containment of the stack compartment; the horizontal pressure vessel can be installed in a sealed cabin or compartment on board;

[0009] The partition is arranged in the horizontal pressure container, forming a left chamber and a right chamber in the horizontal pressure container, and the upper parts of the left chamber and the right chamber are connected to each other;

[0010] The venturi scrubbing unit is disposed in the left chamber and connected to the air inlet disposed on the horizontal pressure vessel, and is used to remove radioactive aerosol particles, radioactive iodine, and decay heat from the mixed gas discharged from the stack containment;

[0011] The demisting unit is arranged above the Venturi scrubbing unit, and is used to separate steam and water from the mixed gas after being processed by the Venturi scrubbing unit, and the mist droplets formed by condensation of the steam and water separation flow back into the Venturi scrubbing unit;

[0012] The metal fiber filter unit is arranged in the right chamber, and is used to filter the mixed gas after being processed by the demisting unit to further remove radioactive aerosol particles, and the mixed gas processed by the metal fiber filter unit is discharged from the horizontal pressure vessel through the gas outlet arranged on the horizontal pressure vessel.

[0013] Further, the metal fiber filter unit comprises a primary filter unit, a medium filter unit, and a fine filter unit stacked in sequence, and a first gas distribution layer is provided between the primary filter unit and the medium filter unit, and a second gas distribution layer is provided between the medium filter unit and the fine filter unit;

[0014] The mixed gas treated by the demisting unit flows through the primary filter unit, the medium filter unit, and the fine filter unit in sequence, and then is discharged from the horizontal pressure vessel from the outlet provided on the horizontal pressure vessel through the outlet pipe.

[0015] Furthermore, the primary filter unit comprises a primary filter layer and a first coarse filter layer, the airflow passes through the primary filter layer and the first coarse filter layer successively, and the filtered gas enters the first gas distribution layer;

[0016] The medium-efficiency filtration unit comprises a second coarse filtration layer and a first medium filtration layer. The airflow first passes through the second coarse filtration layer to further filter millimeter-sized water droplets and aerosol particles, and then passes through the first medium filtration layer to preliminarily filter micron-sized water droplets and aerosols. The filtered gas enters the second gas distribution layer.

[0017] The fine filtration unit includes a second middle filtration layer and a fine filtration layer. The second middle filtration layer first further filters micron-sized water droplets and aerosols from the gas, and the fine filtration layer further filters submicron-sized water droplets and aerosols from the gas.

[0018] Each filter layer is made of metal fiber felt with a set wire diameter, and the two filter layers in the same filter unit and the filter layers between different filter units have different metal fiber wire diameters.

[0019] Furthermore, the metal fiber filter unit is a cubic structure with a cavity in the middle;

[0020] The left side wall, front side wall and rear side wall of the cubic structure are all stacked in sequence by the primary filter unit, the medium filter unit and the fine filter unit, and the remaining side walls are shell structures provided with the air outlet pipe.

[0021] Further, the Venturi scrubbing unit comprises an air intake assembly and a Venturi nozzle;

[0022] The washing liquid can be contained in the left chamber;

[0023] One end of the air intake assembly is connected to the air inlet, and the other end is connected to the venturi nozzle, and the venturi nozzle is located in the washing liquid;

[0024] The mixed gas discharged from the stack containment vessel sequentially passes through the gas inlet, the gas inlet assembly, and the venturi nozzle before entering the scrubbing liquid, and the scrubbing liquid is used to remove radioactive aerosol particles, radioactive iodine, and decay heat from the mixed gas discharged from the stack containment vessel;

[0025] The air intake assembly includes an inlet pipe, a connecting elbow, a connecting pipe, an air distribution pipe and an air distribution manifold;

[0026] One end of the inlet pipe is connected to the air inlet on the horizontal pressure vessel by welding, and the other end is welded to the connecting elbow, the connecting pipe, and the air distribution pipe in sequence, the length-to-diameter ratio of the connecting pipe L / D≥5, the inlet pipe and the air distribution pipe are both arranged horizontally, and the connecting pipe is arranged vertically; both ends of the air distribution pipe are blocked, and the interface arranged at the center of the top surface of the air distribution pipe is connected to the connecting pipe by welding, and multiple interfaces connected by welding to the air distribution manifold are symmetrically arranged on both sides of the air distribution pipe, and the bottom end of the air distribution pipe is welded to the bottom of the horizontal pressure vessel;

[0027] The gas distribution manifold is connected to the Venturi nozzle via a flange.

[0028] Furthermore, the distance between the Venturi nozzle and the demisting unit is 50 to 150 mm;

[0029] The washing liquid is an alkaline mixed solution containing NaOH and Na2S2O3;

[0030] The pH value of the alkaline solution is 9-13.6.

[0031] Furthermore, the demisting unit includes a stainless steel wire mesh filler.

[0032] Furthermore, the horizontal pressure vessel is provided with a manhole for maintenance personnel to enter the horizontal pressure vessel for maintenance.

[0033] Further, a liquid return port is provided at the bottom of the left chamber, a sewage discharge port is provided at the bottom of the right chamber, and the liquid return port and the sewage discharge port are connected to the discharge system of the stack containment;

[0034] The top of the horizontal pressure vessel is also provided with a process interface, which can be used to measure the liquid level or pressure in the horizontal pressure vessel.

[0035] Furthermore, the horizontal pressure vessel is made of stainless steel, and the thickness of the horizontal pressure vessel is 5 to 10 mm.

[0036] Beneficial effects:

[0037] 1. Compared with the conventional scheme of using the existing sealed cabin or compartment on board as the outer shell of the filtering device, the filtering and discharging device of the marine nuclear power system uses a horizontal pressure vessel as the outer shell, so that the horizontal pressure vessel can be installed in the sealed cabin or compartment on board, and the remaining space of the sealed cabin or compartment on board can be used for other purposes. The components of the filtering and discharging device are also easy to install in the horizontal pressure vessel. The entire filtering and discharging device is integrated in a horizontal pressure vessel, which can meet the requirements of miniaturization and integration of the marine nuclear power system space. Moreover, by designing the material and thickness of the horizontal pressure vessel, it can withstand the pressure relief requirements of the reactor containment after a severe accident. In addition, through the combined action of the Venturi scrubbing unit, the demisting unit and the metal fiber filtering unit, it can have an efficient filtering effect on the radioactive aerosol and iodine released from the reactor containment during a severe accident, so as to ensure the nuclear radiation safety of personnel and the environment. Moreover, by adopting the integrated design concept and the design scheme of the left and right chambers, the Venturi washing unit, the demisting unit and the metal fiber filter unit are integrated in the left and right chambers in the horizontal pressure vessel tank body. Through the structural design of the left and right chambers, it is possible to effectively avoid local gas accumulation in the device to cause vibration or blockage.

[0038] 2. The particle sizes of radioactive aerosol particles filtered by the primary filter unit, the medium filter unit, and the fine filter unit decrease in sequence. In this way, the mixed gas has a suitable flow rate when passing through the metal fiber filter unit, achieving efficient filtration of radioactive aerosol particles of different particle sizes, thereby improving filtration efficiency and safety.

[0039] 3. The first gas distribution layer and the second gas distribution layer make the gas after passing through the filter unit evenly mixed again, providing uniform filtering conditions for the next level of filter unit.

[0040] 4. The mixed gas is filtered through the left side wall, front side wall and rear side wall of the metal fiber filter unit. In this way, a suitable air intake area can be ensured, the load of the metal fiber filter unit can be reduced, the pressure loss of the mixed gas can be reduced, and the mixed gas can obtain a suitable flow rate as a whole when passing through the metal fiber filter unit, thereby further improving the filtering effect.

[0041] 5. The top surface of the metal fiber filter unit is separated from the inner top wall of the horizontal pressure vessel by a set distance, so that space can be provided for maintenance and inspection, making it convenient for maintenance personnel to repair the metal fiber filter unit.

[0042] 6. The distance between the Venturi nozzle and the demisting unit is 50-150 mm. The scrubbing liquid is an alkaline mixed solution containing NaOH and Na2S2O3. The pH value of the alkaline solution is 9-13.6. In this way, the scrubbing liquid has a better scrubbing effect on the mixed gas, removing most of the radioactive aerosol particles, radioactive iodine, and decay heat in the mixed gas. Moreover, it can enable the demisting unit to better form droplets and flow back to the Venturi scrubbing unit, thereby improving the scrubbing and demisting effects.

[0043] 7. By using stainless steel wire mesh filler in the demisting unit, the mixed gas can be dehumidified, the load of the subsequent metal fiber filter unit can be reduced, and the steam-water separation can be achieved, the emission of water droplets can be reduced, and the risk of environmental pollution can be further reduced.

[0044] 8. A manhole is provided on the horizontal pressure vessel so that maintenance personnel can enter the horizontal pressure vessel for maintenance, which improves the maintainability and operational safety of the device.

[0045] 9. A liquid return port is provided at the bottom of the left chamber, and a sewage discharge port is provided at the bottom of the right chamber. The liquid return port and the sewage discharge port are connected to the discharge system of the stack containment, so that the waste liquid in the horizontal pressure vessel can be discharged smoothly. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 A schematic structural diagram of a filtering and discharging device for an offshore nuclear power system provided by an embodiment of the present invention;

[0047] Figure 2 for Figure 1 Structural schematic diagram of a medium horizontal pressure vessel;

[0048] Figure 3 for Figure 1 The structural schematic diagram of the metal fiber filter unit;

[0049] Figure 4 for Figure 3 Detailed structural diagram at A in the middle;

[0050] Figure 5 Streamline distribution diagram in the Venturi washing unit structure of the present invention;

[0051] Among them: 1-horizontal pressure vessel; 11-air inlet; 12-process interface; 13-air outlet; 14-base; 15-drain outlet; 16-partition; 17-liquid return port;

[0052] 2-Venturi scrubber unit; 21-air intake assembly; 211-inlet pipe; 212-connecting elbow; 213-connecting pipe; 214-air distribution pipe; 215-air distribution manifold; 22-Venturi nozzle; 23-scrubbing liquid;

[0053] 3- Demisting unit;

[0054] 4-metal fiber filter unit; 41-primary filter unit; 411-primary filter layer; 412-first coarse filter layer; 413-first gas distribution layer; 42-medium filter unit; 421-second coarse filter layer; 422-first medium filter layer; 423-second gas distribution layer; 43-fine filter unit; 431-second medium filter layer; 432-fine filter layer. DETAILED DESCRIPTION

[0055] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0056] Reference Figure 1-Figure 5 , a filtering and discharging device for an offshore nuclear power system, comprising a horizontal pressure vessel 1, a baffle 16, a venturi scrubber unit 2, a demisting unit 3 and a metal fiber filter unit 4, wherein:

[0057] The horizontal pressure vessel 1 is provided with an air inlet 11, which is used to connect with the pressure relief discharge channel in the stack cabin containment, and can actively receive the radioactive high-pressure mixed gas discharged from the stack containment; the horizontal pressure vessel 1 is installed in a sealed cabin or compartment on the ship through a base 14 arranged at the bottom; a partition 16 is arranged in the horizontal pressure vessel 1, and a left chamber and a right chamber are formed in the horizontal pressure vessel 1, and the upper parts of the left chamber and the right chamber are connected to each other; a venturi scrubbing unit 2 is arranged in the left chamber, and is connected to the air inlet 11 arranged on the horizontal pressure vessel 1, and is used to remove the mixed gas discharged from the stack containment. Radioactive aerosol particles, radioactive iodine, and decay heat in the gas; the demisting unit 3 is arranged above the venturi washing unit 2, and is used to separate the mixed gas treated by the venturi washing unit 2 into steam and water, and the droplets formed by the condensation of the steam and water separation flow back into the venturi washing unit 2; the metal fiber filter unit 4 is arranged in the right chamber, and is used to filter the mixed gas treated by the demisting unit 3, and further remove the radioactive aerosol particles, and the mixed gas treated by the metal fiber filter unit 4 is discharged from the horizontal pressure vessel 1 through the gas outlet 13 arranged on the horizontal pressure vessel 1.

[0058] Thus, compared with the conventional scheme of using the existing sealed cabin or compartment on board as the outer shell of the filtering device, the offshore nuclear power system uses the horizontal pressure vessel 1 as the outer shell of the filtering and discharging device, and the horizontal pressure vessel 1 can be installed in the sealed cabin or compartment on board. The remaining space of the sealed cabin or compartment on board can be used for other purposes. The components of the filtering and discharging device are also easy to install in the horizontal pressure vessel 1. The entire filtering and discharging device is integrated in a horizontal pressure vessel 1, which can meet the requirements of miniaturization and integration of the offshore nuclear power system space. Moreover, by designing the material and thickness of the horizontal pressure vessel 1, it can withstand the pressure relief requirements of the reactor containment after a severe accident. In addition, through the combined action of the Venturi scrubbing unit 2, the demisting unit 3 and the metal fiber filtering unit 4, it can have an efficient filtering effect on the radioactive aerosol and iodine released from the reactor containment during a severe accident, so as to ensure the nuclear radiation safety of personnel and the environment. Moreover, by adopting the integrated design concept and the design scheme of the left and right chambers, the Venturi washing unit 2, the demisting unit 3 and the metal fiber filtering unit 4 are integrated in the left and right chambers in the tank body of the horizontal pressure vessel 1. Through the structural design of the left and right chambers, it is possible to effectively avoid local gas accumulation in the device to cause vibration or blockage.

[0059] As an example, the metal fiber filter unit 4 includes a primary filter unit 41, a medium filter unit 42, and a fine filter unit 43 stacked in sequence, and a first gas distribution layer 413 is provided between the primary filter unit 41 and the medium filter unit 42, and a second gas distribution layer 423 is provided between the medium filter unit 42 and the fine filter unit 43; the mixed gas treated by the demisting unit 3 flows through the primary filter unit 41, the medium filter unit 42, and the fine filter unit 43 in sequence, and then is discharged from the horizontal pressure vessel 1 through the gas outlet pipe from the gas outlet 13 provided on the horizontal pressure vessel 1. The three-stage filter unit of the primary filter unit 41, the medium filter unit 42, and the fine filter unit 43 enables the filter discharge device to meet the filtration efficiency requirements for the aerosol, and the first gas distribution layer 413 and the second gas distribution layer 423 make the gas after passing through the filter unit evenly mixed again, providing uniform filtration conditions for the next stage filter unit.

[0060] As an example, the primary filter unit 41 includes a primary filter layer 411 and a first coarse filter layer 412. The airflow passes through the primary filter layer 411 and the first coarse filter layer 412 in sequence. The primary filter layer 411 is used to filter large particles of water droplets and large particles of water droplets containing aerosols. The first coarse filter layer 412 is used to filter millimeter-sized water droplets and water droplets containing aerosols. The filtered gas enters the first gas distribution layer 413; the medium-efficiency filter unit 42 includes a second coarse filter layer 421 and a first medium filter layer 422. The airflow first passes through the second coarse filter layer 421 to further filter millimeter-sized water droplets and aerosol particles. , then the first middle filter layer 422 performs preliminary filtration on micron-sized water droplets and aerosols, and the filtered gas enters the second gas distribution layer 423; the fine filter unit 43 includes a second middle filter layer 431 and a fine filter layer 432, the second middle filter layer 422 first further filters micron-sized water droplets and aerosols on the gas, and the fine filter layer 432 then filters submicron-sized water droplets and aerosols in the gas; each filter layer is made of metal fiber felt with a set wire diameter, and the two filter layers in the same filter unit and the filter layers between different filter units have different metal fiber wire diameters. Specifically, each filter layer can be made of metal fiber felt made of stainless steel 316L. The particle sizes of the radioactive aerosol particles filtered by the primary filter unit 41, the medium filter unit 42, and the fine filter unit 43 decrease in sequence. The primary filter unit 41 is used to capture conventional-sized particles (droplets), the medium filter unit 42 is used to capture micron-sized particles (droplets), and the fine filter unit 43 is used to capture micron-sized and submicron-sized particles (droplets). In this way, the mixed gas has a suitable flow rate when passing through the metal fiber filter unit 4, thereby achieving efficient filtration of radioactive aerosol particles of different particle sizes and improving filtration efficiency and safety.

[0061] As an example, see Figure 3The metal fiber filter unit is a cubic structure with a cavity in the middle. The left side wall, front side wall and rear side wall of the cubic structure are stacked in sequence by a primary filter unit 41, a medium filter unit 42 and a fine filter unit 43, and the other three side walls are shell structures with an air outlet pipe.

[0062] More specifically, in this embodiment, the top surface of the metal fiber filter unit 4 is spaced a set distance from the inner top wall of the horizontal pressure vessel 1. In this way, space can be provided for maintenance and inspection, making it convenient for maintenance personnel to repair the metal fiber filter unit 4. Moreover, the venturi washing unit 2 includes an air intake assembly 21 and a venturi nozzle 22. The air intake assembly 21 of the venturi washing unit 2 is connected to the horizontal pressure vessel 1 by welding, and the venturi nozzle 22 is installed above the air intake assembly 21 in the form of a flange connection. The air intake assembly 21 is used to evenly distribute the gas to the venturi nozzle 22. The washing liquid 23 can be accommodated in the left chamber. One end of the air intake assembly 21 is connected to the air inlet 11, and the other end is connected to the venturi nozzle 22. The number of the venturi nozzles 22 can be configured to be 1 to 8 according to the processing volume requirements, and the venturi nozzle 22 is located in the washing liquid; the mixed gas discharged from the stack containment passes through the air inlet 11, the air intake assembly 21, and the venturi nozzle 22 in sequence and then enters the washing liquid 23, and the radioactive aerosol particles, radioactive iodine, and decay heat in the mixed gas discharged from the stack containment are removed by the washing liquid 23. Specifically, the mixed gas discharged from the stack containment is evenly distributed to the Venturi nozzle 22 through the air inlet assembly 21, and is fully contacted with the washing liquid 23 after being accelerated by the Venturi nozzle 22. Most of the radioactive aerosols and almost all of the iodine are retained in the washing liquid 23. Then the gas passes through the demisting unit 3 to condense a large number of droplets and flow back into the washing liquid 23. Small particles of aerosol and droplets are retained in the metal fiber filter unit 4 after passing through the primary filter unit 41, the medium filter unit 42 and the fine filter unit 43 with the gas. The filtered gas is discharged from the air outlet 13. If the liquid level of the washing liquid 23 is lower than the height of the liquid suction port of the Venturi nozzle 22, the washing liquid 23 can be replenished from the liquid return port 17.

[0063] As an example, see Figure 2The air intake assembly includes an inlet pipe 211, a connecting elbow 212, a connecting pipe 213, an air distribution pipe 214 and an air distribution manifold 215; one end of the inlet pipe 211 is connected to the air inlet 11 on the horizontal pressure vessel 1 by welding, and the other end is welded to the connecting elbow 212, the connecting pipe 213 and the air distribution pipe 214 in sequence, the length-to-diameter ratio L / D of the connecting pipe 213 is ≥5, the inlet pipe 211 and the air distribution pipe 214 are both horizontally arranged, and the connecting pipe 213 is vertically arranged; both ends of the air distribution pipe 214 are blocked, and the interface arranged at the center of the top surface of the air distribution pipe 214 is connected to the connecting pipe 213 by welding, and multiple interfaces connected to the air distribution manifold 215 are symmetrically arranged on both sides of the air distribution pipe 214, and the bottom end of the air distribution pipe 214 is welded to the bottom of the horizontal pressure vessel 1; the air distribution manifold 215 is connected to the Venturi nozzle 22 through a flange. The length to diameter ratio L / D of the connecting pipe 213 is ≥5, which can ensure the flow stability of the gas before entering the gas distribution pipe 214. The gas distribution manifold 215 obtains the optimal inner diameter according to the gas flow rate, and can evenly distribute the gas to the Venturi nozzle 22, ensuring that the gas flow entering each Venturi nozzle 22 is consistent. The Venturi nozzle 22 is configured with the optimal number according to the gas flow rate, which can enable each Venturi nozzle 22 to achieve the best atomization effect under the optimal gas processing volume, thereby ensuring that the Venturi washing unit 2 has the best washing and filtration effect.

[0064] In this embodiment, the distance between the venturi nozzle 22 and the demisting unit 3 is 50-150 mm, and the washing liquid 23 is an alkaline mixed solution containing NaOH and Na2S2O3, and the pH value of the alkaline solution is 9-13.6. In this way, the washing liquid 23 has a better washing effect on the mixed gas, removing most of the radioactive aerosol particles, radioactive iodine, and decay heat in the mixed gas, and can make the demisting unit 3 better form droplets and flow back to the venturi washing unit 2, thereby improving the washing and demisting effects.

[0065] More specifically, in this embodiment, the demisting unit 3 includes a stainless steel wire mesh filler, which can dehumidify the mixed gas, reduce the load of the subsequent metal fiber filter unit 4, and achieve steam-water separation, reduce the discharge of water droplets, and further reduce the risk of environmental pollution. In addition, a manhole (not shown in the figure) is provided on the horizontal pressure vessel 1 to allow maintenance personnel to enter the horizontal pressure vessel 1 for maintenance and maintenance, thereby improving the maintainability and operational safety of the device. In addition, referring to Figure 1The bottom of the left chamber is provided with a liquid return port 17, and the bottom of the right chamber is provided with a sewage outlet 15 (some liquid droplets carried by the mixed gas will accumulate in the right chamber). The liquid return port 17 and the sewage outlet 15 are connected to the discharge system of the stack containment. The top of the horizontal pressure vessel 1 is also provided with a process interface 12, which can be used to measure the liquid level or pressure in the horizontal pressure vessel 1. In particular, in this embodiment, the horizontal pressure vessel 1 is made of stainless steel, and the thickness of the horizontal pressure vessel 1 is 5 to 10 mm, which can meet the pressure and corrosion resistance requirements.

[0066] The venturi scrubber unit 2 in this embodiment removes most of the radioactive aerosols and almost all of the iodine by means of passive chemical scrubbing, and condenses the discharged gas; the demisting unit 3 can effectively reduce the humidity of the mixed gas entering the metal fiber filter unit 4; the metal fiber filter unit 4 adopts a three-stage asymmetric unit combination to further purify the radioactive aerosols and droplets with smaller particle sizes. Therefore, the filtering and discharging device has an efficient filtering effect on the radioactive aerosols and iodine released from the stack containment during a serious accident, and can ensure the nuclear radiation safety of personnel and the environment. Specifically, when a serious accident occurs, the mixed gas containing radioactive substances in the stack containment directly enters the tank through the air inlet 11, the venturi scrubber unit 2 washes and filters most of the aerosols and almost all of the iodine in the mixed gas, and effectively removes the decay heat, the demisting unit 3 condenses a large number of droplets in the filtered mixed gas and returns them to the scrubbing liquid, and the metal fiber filter unit 4 adopts a three-stage asymmetric unit combination to effectively remove the submicron aerosols in the mixed gas. The filtering and discharging device provided in this embodiment has a compact structure, is safe and reliable, and through integrated design, not only the volume and weight are effectively reduced, but also the dual functions of active pressure relief and water washing filtration can be achieved, greatly reducing the demand for overall resources.

[0067] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A filtering and discharging device for an offshore nuclear power system, characterized in that: It includes a horizontal pressure vessel, a baffle, a venturi scrubber unit, a demisting unit, and a metal fiber filter unit; The horizontal pressure vessel is provided with an air inlet for connecting with the pressure relief discharge channel in the containment of the stack compartment; the horizontal pressure vessel can be installed in a sealed cabin or compartment on board; The partition is arranged in the horizontal pressure vessel, forming a left chamber and a right chamber in the horizontal pressure vessel, and the upper parts of the left chamber and the right chamber are connected to each other; The venturi scrubbing unit is arranged in the left chamber and connected to the air inlet arranged on the horizontal pressure vessel, and is used to remove radioactive aerosol particles, radioactive iodine, and decay heat from the mixed gas discharged from the stack containment; The demisting unit is arranged above the Venturi scrubbing unit, and is used to separate the gas mixture after being treated by the Venturi scrubbing unit into steam and water, and the mist droplets formed by the condensation of the steam and water separation flow back into the Venturi scrubbing unit; The metal fiber filter unit is arranged in the right chamber, and is used for filtering the mixed gas processed by the demisting unit to further remove the radioactive aerosol particles, and the mixed gas processed by the metal fiber filter unit is discharged from the horizontal pressure vessel through the gas outlet arranged on the horizontal pressure vessel.

2. A filtering and discharging device for an offshore nuclear power system according to claim 1, characterized in that: The metal fiber filter unit comprises a primary filter unit, a medium filter unit, and a fine filter unit which are stacked in sequence, and a first gas distribution layer is arranged between the primary filter unit and the medium filter unit, and a second gas distribution layer is arranged between the medium filter unit and the fine filter unit; The mixed gas treated by the demisting unit flows through the primary filter unit, the medium filter unit, and the fine filter unit in sequence, and then is discharged from the horizontal pressure vessel from the outlet provided on the horizontal pressure vessel through the outlet pipe.

3. A filtering and discharging device for an offshore nuclear power system according to claim 2, characterized in that: The primary filter unit comprises a primary filter layer and a first coarse filter layer, the airflow passes through the primary filter layer and the first coarse filter layer successively, and the filtered gas enters the first gas distribution layer; The medium-efficiency filtration unit comprises a second coarse filtration layer and a first medium filtration layer. The airflow first passes through the second coarse filtration layer to further filter millimeter-sized water droplets and aerosol particles, and then passes through the first medium filtration layer to preliminarily filter micron-sized water droplets and aerosols. The filtered gas enters the second gas distribution layer. The fine filtration unit includes a second middle filtration layer and a fine filtration layer. The second middle filtration layer first further filters micron-sized water droplets and aerosols from the gas, and the fine filtration layer further filters submicron-sized water droplets and aerosols from the gas. Each filter layer is made of metal fiber felt with a set wire diameter, and the two filter layers in the same filter unit and the filter layers between different filter units have different metal fiber wire diameters.

4. A filtering and discharging device for an offshore nuclear power system according to claim 3, characterized in that: The metal fiber filter unit is a cubic structure with a cavity in the middle; The left side wall, front side wall and rear side wall of the cubic structure are all stacked in sequence by the primary filter unit, the medium filter unit and the fine filter unit, and the remaining side walls are shell structures provided with the air outlet pipe.

5. A filtering and discharging device for an offshore nuclear power system according to any one of claims 1 to 4, characterized in that: The venturi scrubbing unit comprises an air intake assembly and a venturi nozzle; The washing liquid can be contained in the left chamber; One end of the air intake assembly is connected to the air inlet, and the other end is connected to the venturi nozzle, and the venturi nozzle is located in the washing liquid; The mixed gas discharged from the stack containment vessel sequentially passes through the gas inlet, the gas inlet assembly, and the venturi nozzle before entering the scrubbing liquid, and the scrubbing liquid is used to remove radioactive aerosol particles, radioactive iodine, and decay heat from the mixed gas discharged from the stack containment vessel; The air intake assembly includes an inlet pipe, a connecting elbow, a connecting pipe, an air distribution pipe and an air distribution manifold; One end of the inlet pipe is connected to the air inlet on the horizontal pressure vessel by welding, and the other end is welded to the connecting elbow, the connecting pipe, and the air distribution pipe in sequence, the length-to-diameter ratio of the connecting pipe L / D≥5, the inlet pipe and the air distribution pipe are both arranged horizontally, and the connecting pipe is arranged vertically; both ends of the air distribution pipe are blocked, and the interface arranged at the center of the top surface of the air distribution pipe is connected to the connecting pipe by welding, and multiple interfaces connected by welding to the air distribution manifold are symmetrically arranged on both sides of the air distribution pipe, and the bottom end of the air distribution pipe is welded to the bottom of the horizontal pressure vessel; The gas distribution manifold is connected to the Venturi nozzle via a flange.

6. A filtering and discharging device for an offshore nuclear power system according to claim 5, characterized in that: The distance between the venturi nozzle and the demisting unit is 50 to 150 mm; The washing liquid is an alkaline mixed solution containing NaOH and Na2S2O3; The pH value of the alkaline solution is 9-13.

6.

7. A filtering and exhausting device for an offshore nuclear power system according to claim 1, characterized in that: The demisting unit includes a stainless steel wire mesh packing.

8. The filtering and exhausting device for an offshore nuclear power system according to claim 1, characterized in that: The horizontal pressure vessel is provided with a manhole for maintenance personnel to enter the horizontal pressure vessel for maintenance.

9. A filtering and discharging device for an offshore nuclear power system according to claim 1, characterized in that: The bottom of the left chamber is provided with a liquid return port, the bottom of the right chamber is provided with a sewage discharge port, and the liquid return port and the sewage discharge port are connected to the discharge system of the stack containment; The top of the horizontal pressure vessel is also provided with a process interface, which can be used to measure the liquid level or pressure in the horizontal pressure vessel.

10. A filtering and discharging device for an offshore nuclear power system according to claim 1, characterized in that: The horizontal pressure container is made of stainless steel, and the thickness of the horizontal pressure container is 5 to 10 mm.

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