What are the applications of mixed ion exchangers in the power industry

Source：m.lingjang.com Release date： 2025-11-25

The mixed ion exchanger (referred to as "mixed bed") is a core equipment for the preparation of pure/ultrapure water in the power industry. With its core advantages of deep desalination (simultaneous removal of cations and anions in water), pure effluent water quality (conductivity ≤ 0.1 μ S/cm, SiO ? ≤ 20 μ g/L), and stable operation, it is suitable for the strict requirements of the power industry for "high purity and low impurities" in water quality (especially in key scenarios such as boiler feedwater and cooling system makeup water, where impurities can cause equipment scaling, corrosion, and pipe bursting). The following are the main application scenarios of it in the power industry, combined with the classification of unit types and water quality requirements:
1、 Thermal power industry (traditional thermal power, circulating fluidized bed power plants)
1. Boiler feedwater treatment system (core application scenario)
Application logic: Thermal power boilers (especially high-pressure, high-pressure, subcritical/supercritical boilers) have high requirements for the purity of feedwater. Excessive salt and silicon content in water can lead to scaling of boiler water-cooled walls and superheaters (reducing heat transfer efficiency and increasing energy consumption), and even cause corrosion and tube bursting.
2.Specific scenario:
Pre treatment (clarification, filtration)+reverse osmosis (RO)+mixed bed deep treatment: The mixed bed serves as the final fine treatment equipment to remove trace amounts of Na ?, Cl ?, SiO ∝ 2 ? plasma remaining in the RO produced water, ensuring that the feedwater quality meets the GB/T 12145-2016 "Water and Steam Quality of Thermal Power Units and Steam Power Equipment" standard (supercritical unit feedwater conductivity ≤ 0.1 μ S/cm, SiO ? ≤ 10 μ g/L);
Condensed water polishing system: For units above high pressure, impurities may be introduced into the condensed water during circulation due to system leakage and metal corrosion. It needs to be deeply treated through a "high-speed mixed bed" (operating flow rate can reach 60-120m/h) to ensure that the condensed water is directly returned to the boiler and avoid water pollution.
Core requirements: high desalination efficiency, large processing flow rate, anti pollution (tolerance to iron and copper oxides in condensate water).
2. Closed loop cooling water system replenishment
Application scenario: Closed cooling water for thermal power units (used to cool equipment such as turbines and generators) needs to maintain high purity to prevent scaling and corrosion of cooling water pipelines and extend equipment life;
Function: The pure water treated by the mixed bed serves as supplementary water, replacing traditional softened water, reducing the salt content in the cooling water, decreasing the amount of corrosion and scale inhibitors used, and lowering operating costs.
3. Supporting facilities for desulfurization and denitrification systems
Application scenarios: Process water replenishment for thermal power desulfurization systems (such as limestone gypsum method), preparation of dilution water for denitrification systems (SCR);
Function: Remove impurity ions from water, avoid equipment blockage caused by salt accumulation in desulfurization slurry, and prevent denitrification catalyst from being poisoned and ineffective due to water quality impurities.
2、 Nuclear power industry (pressurized water reactor, boiling water reactor nuclear power plants)
1. Purification of primary coolant (key equipment of nuclear island)
Application logic: The coolant in the primary circuit of a nuclear power plant (containing boron water) comes into direct contact with nuclear fuel and needs to maintain high purity to prevent the accumulation of radioactive corrosion products (such as Co-60, Ni-58), as well as to avoid impurities in the coolant that can cause equipment corrosion and radioactive leakage.
Specific scenario:
Adopting an "extracorporeal circulation mixed bed" (designed with a shielding layer to prevent radiation leakage), the primary coolant is continuously purified to remove corrosion products and trace ion impurities, ensuring that the coolant water quality meets the nuclear power industry standards (conductivity ≤ 0.1 μ S/cm, total dissolved solids ≤ 10 μ g/L);
The mixed bed resin should be radiation resistant (such as strong acid cation resin with cross-linking degree ≥ 12%+strong alkali anion resin) to avoid degradation and failure of the resin caused by radiation.
2. Secondary loop feedwater/condensate fine treatment
Application scenario: Deep treatment of feedwater and condensate in the secondary loop (steam generator side) of nuclear power plants;
Function: Remove impurities such as Na ?, Cl ?, SiO ? from water, prevent scaling and corrosion of steam generator tubes (heat transfer tubes) (nuclear power steam generator tubes are mostly made of Inconel alloy, and excessive chloride ions can cause stress corrosion cracking), and ensure the safe operation of the secondary loop system.
3. Preparation of pure water for auxiliary systems
Application scenarios: chemical dosing systems in nuclear power plants, equipment flushing water, laboratory water, etc;
Function: The mixed bed serves as the final precision treatment equipment, providing ultra pure water to meet the high purity requirements of the auxiliary system for water quality.
3、 New energy power industry (photovoltaic, wind power, energy storage power stations)
1. Cooling/cleaning water for photovoltaic power plants
Application scenarios: Cleaning water for photovoltaic panels in large centralized photovoltaic power plants, and replenishing water for cooling systems of photovoltaic inverters;
Function: The pure water treated by mixed bed can avoid residual scale during cleaning, which affects the transmittance of photovoltaic panels, and prevent scaling of cooling system pipelines, ensuring the heat dissipation efficiency of inverters.
2. Auxiliary water for wind power operation and maintenance
Application scenarios: Equipment cleaning and hydraulic system water replenishment for offshore or onshore wind power;
Function: Remove impurities, ions, and particulate matter from water, avoid corrosion and blockage of hydraulic system pipelines, and extend the operation and maintenance cycle of wind power equipment.
3. Preparation of cooling medium for energy storage power stations (liquid cooled type)
Application scenario: Preparation of cooling circulating water for liquid cooled energy storage power plants (such as dilution water for ethylene glycol aqueous solution);
Function: After deep desalination in the mixed bed, it can reduce the conductivity of the cooling medium, avoid electrochemical corrosion of the cooling system, and prevent salt crystallization from blocking the cooling pipeline.
4、 Other power related scenarios (hydropower stations, self owned power stations)
1. Cooling and makeup water for hydropower station equipment
Application scenario: Water replenishment for cooling systems of hydroelectric generating units and transformers in hydropower stations;
Function: Remove calcium, magnesium, chloride ions, etc. from water, prevent scaling and corrosion of cooling pipelines, and ensure long-term stable operation of hydro generators and transformers.
2. Enterprise owned power stations (industrial waste heat power generation, waste incineration power generation)
Application scenario: Self provided power plant boiler feedwater and condensate precision treatment;
Function: Adapt to the water quality requirements of medium and low pressure boilers (conductivity ≤ 1 μ S/cm, SiO ? ≤ 50 μ g/L), deeply remove salt through mixed bed, avoid boiler scaling and corrosion, reduce enterprise power generation costs and equipment maintenance frequency.

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