A coastal nuclear power plant electrolytic chlorine water source switching system

Abstract

The present application belongs to the technical field of nuclear power plant electrolytic chlorine water source switching system, and particularly relates to a kind of seafront nuclear power plant electrolytic chlorine water source switching system, including flow control module and booster pump, the water source used by electrolytic chlorine system is preferentially seawater desalination system reverse osmosis concentrated water, and the insufficient part is supplemented by seawater. Since the content of suspended solids in the reverse osmosis concentrated water of the seawater desalination system is very low, it can meet the water inlet requirement of the electrolytic cell in the chlorine production system without filtration, effectively preventing the mechanical erosion of sand particles in seawater on the electrode of the electrolytic cell. After the reverse osmosis concentrated water of the conventional nuclear power plant seawater desalination system is reused as the water source of the electrolytic chlorine production system, the seawater intake can be saved, the water discharge can be reduced, and the system does not need to add a seawater pool and a seawater pump. The system can automatically switch and adjust the flow of the two water sources, has the characteristics of reducing the occupied area, saving the construction cost, simple system structure, no need for buffering and secondary boosting, and easy operation.

Description

Technical Field

[0001] This invention relates to the technical field of switching systems for chlorine production water sources in nuclear power plants, specifically to a switching system for chlorine production water sources in a coastal nuclear power plant. Background Technology

[0002] Coastal nuclear power plants often use seawater electrolysis to produce chlorine for sterilization and algae removal in their direct-flow circulating cooling water systems. However, high sand content in seawater can severely impact the normal operation of equipment such as electrolyzers. In contrast, the reverse osmosis concentrate from seawater desalination systems has high chloride ion content and low suspended solids, meeting the influent requirements for electrolyzers in chlorination systems. However, due to the operational constraints of seawater desalination systems, the reverse osmosis concentrate flow rate is unstable, making it difficult to guarantee stable operation of the electrolyzers.

[0003] The water source for the chlorine production system of a conventional nuclear power plant is seawater from the outlet of the circulating cooling water pump. The process flow is as follows:

[0004] Seawater → booster pump → pre-filter → secondary filter → electrolytic cell → sodium hypochlorite storage tank → dosing pump → circulating water intake dosing point.

[0005] Although the above process includes a pre-filter and a secondary filter, operational feedback indicates that when the seawater contains a high amount of sand, the filters are unable to cope, and the sand particles in the seawater will still cause mechanical erosion of the electrolytic cell electrodes, which will seriously affect the normal operation of the electrolytic cell and other equipment. Summary of the Invention

[0006] To address the shortcomings of the above solutions, the purpose of this invention is to solve the problem of high sand content in seawater affecting the normal operation of equipment such as electrolyzers. Simultaneously, with the aim of reducing land occupation and minimizing operation and maintenance workload, an electrolytic chlorine production water source switching system has been developed. This system uses both the original seawater and the reverse osmosis concentrate from the seawater desalination system as the water source for electrolytic chlorine production, and automatically switches between the two sources. This reduces the amount of seawater drawn, mitigates the impact of high sand content in the original seawater on the electrolyzers, and ensures the stable operation of the electrolytic chlorine production system.

[0007] The purpose of this invention is to provide a water source switching system for electrolytic chlorination in a coastal nuclear power plant, including a flow control module and a booster pump. Both the flow control module and the booster pump are installed on the inlet header of the secondary filter. The flow control module is electrically connected to the booster pump. The booster pump is equipped with a frequency converter and a frequency converter control module. The flow control module transmits the flow signal to the frequency converter control module. The frequency converter control module controls the working state of the frequency converter according to the flow signal, realizing automatic frequency conversion of the booster pump, thereby keeping the inlet flow of the electrolytic cell in the chlorination system stable.

[0008] The booster pump is connected to the seawater source. The inlet header of the secondary filter is connected to the seawater source and the concentrated water source of the seawater desalination reverse osmosis via pipelines. A filter group is installed on the pipeline between the booster pump and the flow control module. The output end of the secondary filter is connected to the input end of the electrolytic cell in the chlorination system.

[0009] The water source used in the electrolytic chlorine production system is primarily the concentrated water from the reverse osmosis system of the seawater desalination system, with the remaining portion supplemented by seawater. Because the concentrated water from the reverse osmosis system of the seawater desalination system has a very low suspended solids content, it can meet the influent requirements of the electrolyzer in the chlorine production system without filtration, effectively preventing mechanical erosion of the electrolyzer electrodes by sand particles in the seawater.

[0010] The flow control module adjusts the opening angle of the flow control valve on the seawater desalination reverse osmosis concentrate source pipeline according to preset flow parameters, keeping the influent flow rate of the electrolyzer in the chlorination system constant. If the seawater desalination reverse osmosis concentrate is insufficient, the flow control module adjusts the opening of the flow control valve on the inlet header of the secondary filter, and simultaneously transmits the flow signal to the frequency converter control module. The frequency converter control module controls the operation of the frequency converter according to the flow signal, activating the booster pump to supplement seawater into the electrolyzer in the chlorination system, thereby maintaining a stable influent flow rate to the electrolyzer in the chlorination system. During the process of seawater entering the electrolyzer, it passes through the filter group and the secondary filter to filter out sand particles. Due to the relatively small volume of seawater, the filtration burden is light, achieving a relatively good filtration effect.

[0011] Pipelines, valves, and various instruments are all necessary accessories for the system and are widely used in existing technologies. Therefore, we will not go into detail about the accessories here.

[0012] After the reverse osmosis concentrate from the seawater desalination system of a conventional nuclear power plant is collected, it is pumped to the circulating water drainage well for discharge. After being reused as a water source for the electrolytic chlorination system, it can save seawater intake (about 700 t / h less for two 1 MW units) and reduce the amount of external discharge.

[0013] Furthermore, this design eliminates the need for additional seawater pools and pumps, and allows for automatic switching and adjustment of the flow rates from both water sources. Therefore, this design reduces land occupation and saves on civil engineering costs (the seawater pool volume required for the electrolytic chlorination system of two 1,000 MW nuclear power units is approximately 1,500 cubic meters).

[0014] Preferably, the filter group includes a pre-filter and a cyclone separator. The pre-filter and the cyclone separator respectively pre-filter sand particles in seawater and remove them by rotation and centrifugation. Subsequent secondary filtration can achieve a good filtration effect and prevent sand particles in seawater from mechanically eroding the electrodes of the electrolytic cell.

[0015] Preferably, the pre-filter has a filtration accuracy of 0.5 mm, the cyclone sand separator has a filtration accuracy of 0.3 mm, and the secondary filter has a filtration accuracy of 0.13 mm. The filtration accuracy of the pre-filter, the cyclone sand separator, and the secondary filter decreases from high to low, filtering sand particles in seawater step by step to further improve the filtration effect.

[0016] Preferably, the shell material of the pre-filter and the secondary filter is steel lined with rubber, and the filter screens therein are made of stainless steel that is resistant to seawater corrosion; the material of the cyclone sand remover is steel lined with rubber, and the flow-through components therein are made of stainless steel that is resistant to seawater corrosion.

[0017] Preferably, the seawater desalination reverse osmosis concentrate source has two branch pipelines. One branch pipeline is connected to the inlet main pipe of the secondary filter, and the connection point is located in front of the flow control module. The other branch pipeline is the discharge pipeline. The seawater desalination reverse osmosis concentrate first provides stable inlet water to the electrolyzer in the chlorination system, and the excess seawater desalination reverse osmosis concentrate is discharged along the other branch pipeline.

[0018] Preferably, electrically controlled flow valves are installed on the main inlet pipe of the secondary filter and on the branch pipes connected to it. The flow control module adjusts the opening angle of the flow control valves on the branch pipes according to preset flow parameters to keep the inlet flow of the electrolyzer in the chlorination system constant. The excess seawater desalination reverse osmosis concentrate is discharged through another branch pipe. If the seawater desalination reverse osmosis concentrate is insufficient, the flow control module adjusts the opening of the flow control valve on the main inlet pipe of the secondary filter and transmits the flow signal to the frequency converter control module. The frequency converter control module controls the working state of the frequency converter according to the flow signal, so that the booster pump is put into operation to supplement seawater into the electrolyzer in the chlorination system, thereby keeping the inlet flow of the electrolyzer in the chlorination system stable.

[0019] Preferably, the flow control module includes a pressure transducer and a flow meter. The pressure transducer acts as a sensor to convert liquid pressure into an electric signal, which is transmitted to the electrically controlled flow valve and the frequency converter control module. The flow meter displays the liquid flow reading measured by the pressure transducer.

[0020] The beneficial effects of this invention are:

[0021] (1) In this system, the water source used by the electrolytic chlorine production system is preferentially the reverse osmosis concentrate from the seawater desalination system, and the insufficient part is supplemented by seawater. Since the suspended solids content in the reverse osmosis concentrate from the seawater desalination system is very low, it can meet the water requirements of the electrolyzer in the chlorine production system without filtration, effectively preventing the mechanical scouring of the electrolyzer electrodes by sand particles in the seawater.

[0022] (2) The flow control module adjusts the opening angle of the flow control valve on the seawater desalination reverse osmosis concentrate source pipeline according to preset flow parameters to keep the influent flow rate of the electrolyzer in the chlorination system constant. If the seawater desalination reverse osmosis concentrate is insufficient, the flow control module adjusts the opening of the flow control valve on the influent header of the secondary filter, and simultaneously transmits the flow signal to the frequency converter control module. The frequency converter control module controls the working state of the frequency converter according to the flow signal, so that the booster pump is put into operation to supplement seawater into the electrolyzer in the chlorination system, thereby keeping the influent flow rate of the electrolyzer in the chlorination system stable. During the process of seawater entering the electrolyzer, it will pass through the filter group and the secondary filter to filter the sand particles in the seawater. Since the seawater volume is relatively small, the filtration burden is light, and a relatively good filtration effect can be achieved.

[0023] After the reverse osmosis concentrate from the seawater desalination system of a conventional nuclear power plant is reused as a water source for the electrolytic chlorination system, it can save seawater intake and reduce external discharge. Moreover, this system does not require the addition of seawater pools and seawater pumps, and can automatically switch and adjust the flow of the two water sources, reducing land occupation and saving civil engineering costs.

[0024] This system features automatic switching between two water sources, small footprint, simple system, no need for buffering or secondary pressurization, and convenient operation. Attached Figure Description

[0025] Figure 1 This is a system flowchart of the present invention. Detailed Implementation

[0026] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0027] Please see Figure 1 A water source switching system for electrolytic chlorination in a coastal nuclear power plant includes a flow control module and a booster pump. Both the flow control module and the booster pump are installed on the inlet header of a secondary filter. The flow control module is electrically connected to the booster pump. The booster pump is equipped with a frequency converter and a frequency converter control module. The flow control module transmits the flow signal to the frequency converter control module. The frequency converter control module controls the operating state of the frequency converter according to the flow signal, realizing automatic frequency conversion of the booster pump, thereby keeping the inlet flow of the electrolytic cell in the chlorination system stable.

[0028] The booster pump is connected to the seawater source. The inlet header of the secondary filter is connected to the seawater source and the concentrated water source of the seawater desalination reverse osmosis via pipelines. A filter group is installed on the pipeline between the booster pump and the flow control module. The output end of the secondary filter is connected to the input end of the electrolytic cell in the chlorination system.

[0029] The water source used in the electrolytic chlorine production system is primarily the concentrated water from the reverse osmosis system of the seawater desalination system, with the remaining portion supplemented by seawater. Because the concentrated water from the reverse osmosis system of the seawater desalination system has a very low suspended solids content, it can meet the influent requirements of the electrolyzer in the chlorine production system without filtration, effectively preventing mechanical erosion of the electrolyzer electrodes by sand particles in the seawater.

[0030] The flow control module adjusts the opening angle of the flow control valve on the seawater desalination reverse osmosis concentrate source pipeline according to preset flow parameters, keeping the influent flow rate of the electrolyzer in the chlorination system constant. If the seawater desalination reverse osmosis concentrate is insufficient, the flow control module adjusts the opening of the flow control valve on the inlet header of the secondary filter, and simultaneously transmits the flow signal to the frequency converter control module. The frequency converter control module controls the operation of the frequency converter according to the flow signal, activating the booster pump to supplement seawater into the electrolyzer in the chlorination system, thereby maintaining a stable influent flow rate to the electrolyzer in the chlorination system. During the process of seawater entering the electrolyzer, it passes through the filter group and the secondary filter to filter out sand particles. Due to the relatively small volume of seawater, the filtration burden is light, achieving a relatively good filtration effect.

[0031] Pipelines, valves, and various instruments are all necessary accessories for the system and are widely used in existing technologies. Therefore, we will not go into detail about the accessories here.

[0032] After the reverse osmosis concentrate from the seawater desalination system of a conventional nuclear power plant is collected, it is pumped to the circulating water drainage well for discharge. After being reused as a water source for the electrolytic chlorination system, it can save seawater intake (about 700 t / h less for two 1 MW units) and reduce the amount of external discharge.

[0033] Furthermore, this design eliminates the need for additional seawater pools and pumps, and allows for automatic switching and adjustment of the flow rates from both water sources. Therefore, this design reduces land occupation and saves on civil engineering costs (the seawater pool volume required for the electrolytic chlorination system of two 1,000 MW nuclear power units is approximately 1,500 cubic meters).

[0034] Specifically, the filter group includes a pre-filter and a cyclone separator. The pre-filter and the cyclone separator pre-filter and remove sand particles in seawater by rotation and centrifugation, respectively. Subsequent secondary filtration can achieve a good filtration effect and prevent sand particles in seawater from mechanically eroding the electrodes of the electrolytic cell.

[0035] Specifically, the pre-filter has a filtration accuracy of 0.5 mm, the cyclone sand separator has a filtration accuracy of 0.3 mm, and the secondary filter has a filtration accuracy of 0.13 mm. The filtration accuracy of the pre-filter, the cyclone sand separator, and the secondary filter decreases from high to low, filtering sand particles in seawater step by step to further improve the filtration effect.

[0036] Specifically, the shells of the pre-filter and the secondary filter are made of steel lined with rubber, and the filter screens are made of stainless steel that is resistant to seawater corrosion; the cyclone sand remover is made of steel lined with rubber, and the flow-through components are made of stainless steel that is resistant to seawater corrosion.

[0037] Specifically, the seawater desalination reverse osmosis concentrate source has two branch pipelines. One branch pipeline is connected to the inlet main pipe of the secondary filter, and the connection point is located in front of the flow control module. The other branch pipeline is the discharge pipeline. The seawater desalination reverse osmosis concentrate first provides stable inlet water to the electrolyzer in the chlorination system, and the excess seawater desalination reverse osmosis concentrate is discharged along the other branch pipeline.

[0038] Specifically, electrically controlled flow valves are installed on the main inlet pipe of the secondary filter and on the branch pipes connected to it. The flow control module adjusts the opening angle of the flow control valves on the branch pipes according to preset flow parameters to keep the inlet flow of the electrolyzer in the chlorination system constant. The excess seawater desalination reverse osmosis concentrate is discharged through another branch pipe. If the seawater desalination reverse osmosis concentrate is insufficient, the flow control module adjusts the opening of the flow control valve on the main inlet pipe of the secondary filter and transmits the flow signal to the frequency converter control module. The frequency converter control module controls the working state of the frequency converter according to the flow signal, so that the booster pump is put into operation to supplement seawater into the electrolyzer in the chlorination system, thereby keeping the inlet flow of the electrolyzer in the chlorination system stable.

[0039] Specifically, the flow control module includes a pressure transducer and a flow meter. The pressure transducer acts as a sensor, converting the liquid pressure into an electric signal that is transmitted to the electrically controlled flow valve and the frequency converter control module. The flow meter displays the liquid flow reading measured by the pressure transducer.

[0040] Working Principle: This system includes a flow control module and a booster pump. Both are installed on the inlet header of the secondary filter. The flow control module is electrically connected to the booster pump, which is equipped with a frequency converter and a frequency converter control module. The flow control module transmits the flow signal to the frequency converter control module, which controls the operation of the frequency converter according to the flow signal, realizing automatic frequency conversion of the booster pump, thereby keeping the inlet flow of the electrolyzer in the chlorination system stable. The booster pump is connected to the seawater source. The inlet header of the secondary filter is connected to the seawater source and the seawater desalination reverse osmosis concentrate source through pipelines. A filter group is installed on the pipeline between the booster pump and the flow control module. The output end of the secondary filter is connected to the input end of the electrolyzer in the chlorination system.

[0041] The water source used in the electrolytic chlorine production system is primarily the concentrated water from the reverse osmosis system of the seawater desalination system, with the remaining portion supplemented by seawater. Because the concentrated water from the reverse osmosis system of the seawater desalination system has a very low suspended solids content, it can meet the influent requirements of the electrolyzer in the chlorine production system without filtration, effectively preventing mechanical erosion of the electrolyzer electrodes by sand particles in the seawater.

[0042] The flow control module adjusts the opening angle of the flow control valve on the seawater desalination reverse osmosis concentrate source pipeline according to preset flow parameters, keeping the influent flow rate of the electrolyzer in the chlorination system constant. If the seawater desalination reverse osmosis concentrate is insufficient, the flow control module adjusts the opening of the flow control valve on the inlet header of the secondary filter, and simultaneously transmits the flow signal to the frequency converter control module. The frequency converter control module controls the operation of the frequency converter according to the flow signal, activating the booster pump to supplement seawater into the electrolyzer in the chlorination system, thereby maintaining a stable influent flow rate to the electrolyzer in the chlorination system. During the process of seawater entering the electrolyzer, it passes through the filter group and the secondary filter to filter out sand particles. Due to the relatively small volume of seawater, the filtration burden is light, achieving a relatively good filtration effect.

[0043] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A sea shore nuclear power plant electrolytic chlorine water source switching system, characterized by, The application relates to a chlor-alkali electrolysis system, which comprises a flow control module and a booster pump, both of which are installed on a water inlet main pipe of a secondary filter, the flow control module is electrically connected with the booster pump, the booster pump is provided with a frequency converter and a frequency converter control module, the flow control module transmits a flow signal to the frequency converter control module, the frequency converter control module controls the working state of the frequency converter according to the flow signal, the booster pump realizes automatic frequency conversion, and thus the water inflow of an electrolytic tank in a chlor-alkali system is kept stable. The booster pump is connected with a seawater source, the water inlet main pipe of the secondary filter is connected with the seawater source and a seawater desalination reverse osmosis concentrated water source through pipelines, a filter group is arranged on the pipeline between the booster pump and the flow control module, and the output end of the secondary filter is connected with the input end of the electrolytic tank in the chlor-alkali system. The seawater desalination reverse osmosis concentrated water source has two branch pipelines, one of which is connected with the water inlet main pipe of the secondary filter and is located on the front side of the flow control module, and the other branch pipeline is a seawater discharge pipeline. The flow control module controls the opening angle of a flow control valve on the branch pipeline according to preset flow parameters, so that the water inflow of the electrolytic tank in the chlor-alkali system is kept constant, and the excess seawater desalination reverse osmosis concentrated water is discharged along the other branch pipeline. If the seawater desalination reverse osmosis concentrated water is insufficient, the flow control module controls the opening of the flow control valve on the water inlet main pipe of the secondary filter, simultaneously transmits a flow signal to the frequency converter control module, the frequency converter control module controls the working state of the frequency converter according to the flow signal, the booster pump is put into operation, seawater is supplemented to the electrolytic tank in the chlor-alkali system, and thus the water inflow of the electrolytic tank in the chlor-alkali system is kept stable.

2. The system according to claim 1, wherein, The filter group comprises a pre-filter and a rotary sand remover.

3. The system according to claim 2, wherein, The filtering precision of the pre-filter is 0.5 mm, the filtering precision of the rotary sand remover is 0.3 mm, and the filtering precision of the secondary filter is 0.13 mm.

4. The system according to claim 3, wherein the system further comprises a switch valve for switching the source of the chlorine water between the electrolytic chlorine water generator and the storage tank. The shell materials of the pre-filter and the secondary filter are steel lined rubber, and the filter screens are made of stainless steel which is resistant to seawater corrosion; the material of the rotary sand remover is steel lined rubber, and the flow components are made of stainless steel which is resistant to seawater corrosion.

5. The system according to claim 4, wherein, An electric control flow valve is arranged on the water inlet main pipe of the secondary filter and the branch pipeline connected with the water inlet main pipe.

6. The system according to claim 5, wherein, The flow control module is provided with a pressure transmitter and a flow display meter, the pressure transmitter is used as a sensor to convert liquid pressure into an electric signal which is transmitted to the electric control flow valve and the frequency converter control module, and the flow display meter displays the liquid flow value measured by the pressure transmitter.

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