In industrial recirculating water systems, particularly in glass manufacturing, chemical processing, and other heavy industries, water is reused repeatedly, making it prone to microbial growth, algae proliferation, and biofilm formation. These phenomena accelerate fouling in pipelines, cooling towers, and heat exchangers, increase corrosion risk, and compromise both equipment lifespan and process stability. Conventional chemical disinfection methods, such as liquid chlorine or chlorinated compounds, involve high storage risks, complex handling, and potential formation of harmful by-products. Consequently, there is an increasing demand for efficient, safe, and controllable in-situ disinfection technologies for industrial water treatment.
Working Principle and Technical Features of Small HOCl Electrolytic Cells
Small hypochlorous acid (HOCl) electrolytic cells generate HOCl through electrolysis of sodium chloride (NaCl) solution, following the reactions:
2Cl−+2H2O→ElectrolysisCl2+H2+2OH−
The chlorine gas produced then hydrolyzes in water to form HOCl:
Cl2+H2O→HOCl+H++Cl−
Titanium Anodes in HOCl Electrolytic Cells
Small HOCl electrolytic cells typically employ titanium-based anodes coated with mixed metal oxides (MMO) such as RuO₂, IrO₂, or TiO₂. These anodes are critical for long-term performance and efficiency:
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Electrochemical stability: Titanium is resistant to oxidation and corrosion in chloride-containing solutions.
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Catalytic activity: MMO coatings enhance the conversion of Cl⁻ → Cl₂ → HOCl, improving electrochemical efficiency.
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Longevity: Titanium anodes with MMO coatings typically have lifespans of 3–5 years under continuous operation.
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Low maintenance: Resistant to fouling and degradation, reducing downtime and replacement frequency.
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High current efficiency: Enables effective HOCl generation at lower energy consumption.
Industrial Application Examples
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Glass Manufacturing Recirculating Cooling Water
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Industrial glass furnaces and forming equipment require large volumes of recirculating water at 30–50°C, which promotes microbial growth.
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Small HOCl electrolytic cells generate HOCl in-situ and continuously dose it into the recirculating water, effectively inhibiting microbial and algal growth and preventing biofilm formation.
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Experimental data show that at HOCl concentrations of 1–2 mg/L, total bacterial counts in circulating water can be reduced by over 90%, while significantly decreasing heat exchanger fouling.
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Cooling Towers and Auxiliary Circulating Water Systems
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Cooling tower water, exposed to air and high humidity, is prone to bacterial aggregation and algae growth.
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Coupling small HOCl cells with circulation pumps enables online disinfection, reducing chlorine compound consumption and chemical residues.
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In high-temperature water (40–45°C), HOCl remains stable for 2–4 hours, providing continuous disinfection.
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Boiler Feedwater and Cleaning Water
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Industrial boiler feedwater and equipment cleaning water require strict microbial control to prevent biofilm formation and accelerated corrosion.
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Small HOCl cells generate HOCl from NaCl solution on demand, allowing real-time dosing and maintaining water quality within industrial standards (e.g., total bacterial count <100 CFU/mL).
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Temporary Construction or Small-Scale Industrial Water Management
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Temporary water pools or wash water at industrial sites or construction areas require safe disinfection.
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Modular small HOCl units can be rapidly deployed on-site, providing effective disinfection without the storage or transport risks associated with liquid chlorine.
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Small hypochlorous acid electrolytic cells with titanium MMO anodes provide an in-situ, efficient, safe, and controllable solution for industrial water disinfection. They are suitable for recirculating water systems, auxiliary process water, and temporary water treatment scenarios. The use of titanium anodes ensures long-term durability and high electrochemical efficiency, while HOCl generation effectively controls microbial growth, prevents fouling, and mitigates corrosion. Overall, this technology delivers reliable engineering solutions, enhances system reliability, and reduces operational costs