Against the backdrop of global energy transition and environmental protection upgrading, Vietnam, as an emerging economy in Southeast Asia, has seen a continuous surge in electricity demand. Coastal areas, with their convenient water intake conditions, have become concentrated locations for coal-fired power plants and new energy power stations. However, seawater, as the main water source for circulating cooling systems, poses challenges to the safe operation of power plants due to its high salinity and high biological activity - problems such as pipeline blockages and reduced heat exchange efficiency caused by marine organism attachment are common. In this context, seawater electrochlorination technology, with its advantages of on-site chlorine generation, environmental friendliness and high efficiency, has become a core solution in the field of water treatment for Vietnamese power plants, promoting the green transformation of the local power industry.
Technical Principles: The "Green Transformation" of Seawater Resources
The core of seawater electrochlorination technology is to realize the resource utilization of seawater through electrolytic reactions. In a specially designed electrolytic cell, seawater undergoes electrochemical decomposition under the action of direct current. Sodium chloride (NaCl) and water (H₂O) react to generate sodium hypochlorite (NaClO), hydrogen (H₂) and sodium hydroxide (NaOH). Among them, sodium hypochlorite, as an efficient disinfectant, can quickly destroy the cell membranes and enzyme systems of microorganisms in seawater, kill algae, shellfish and other organisms, and block the biological pollution chain of the circulating water system from the source; hydrogen is safely discharged after collection and treatment to avoid safety hazards; the by-product sodium hydroxide can adjust the pH value of water to reduce equipment corrosion.
The key to this technology lies in electrode materials and intelligent control systems. Vietnamese power plants mostly use titanium-based ruthenium-iridium coated electrodes, whose corrosion resistance is 5-8 times that of ordinary metals, and can operate stably for more than 8 years in a high-salt environment with TDS (Total Dissolved Solids) > 35,000mg/L; the intelligent control system dynamically adjusts the electrolytic current by real-time monitoring of seawater flow, temperature, residual chlorine concentration and other parameters, so that the sodium hypochlorite output can be accurately matched with the sterilization demand, reducing energy consumption by 15%-20% compared with traditional chemical dosing methods.
Practical Application: Technical Adaptation and Innovation in Vietnamese Power Plants
The geographical environment and operational needs of Vietnamese coastal power plants have promoted the formation of differentiated application modes of seawater electrochlorination technology. The following three typical cases show the flexibility and effectiveness of technology implementation.
A 2×620MW supercritical coal-fired power plant along the coast of Vietnam is one of the first projects in the country to apply seawater electrochlorination technology on a large scale. Its circulating cooling water system takes 1.2 million tons of seawater per day. The traditional liquid chlorine disinfection, due to transportation risks and dosage fluctuations, caused the condenser end difference to frequently exceed 5℃, affecting the unit efficiency. After the transformation and introduction of the electrolytic seawater chlorination system in 2022, through the parallel operation of 8 sets of modular electrolytic cells, continuous dosing of sodium hypochlorite (concentration 0.3-0.8mg/L) was realized, the adhesion rate of marine organisms decreased by 90%, the condenser end difference was stably controlled within 3℃, and the annual power generation loss was saved by about 20 million kWh. The project innovatively adopted the "closed-loop utilization of concentrated brine" design, introducing concentrated brine (TDS > 60,000mg/L) from seawater desalination into the electrolytic system, which not only improved the chlorine production efficiency but also reduced wastewater discharge, saving 50,000 tons of water annually.
The "one chlorine multi-purpose" mode of Vinh Tan 3 Power Plant reflects the value of technical collaboration. Its seawater electrochlorination system not only provides bactericidal agents for the circulating water system but also introduces part of sodium hypochlorite into the seawater desalination pretreatment process. By adding 0.5mg/L sodium hypochlorite at the front end of the reverse osmosis membrane, plankton and bacteria are killed, the membrane fouling rate is reduced by 40%, the service life of the membrane module is extended from 3 years to 4.5 years, and the annual replacement cost of a single system is saved by about 800,000 US dollars. At the same time, the system is deeply linked with the plant's DCS system, automatically adjusting the chlorine production according to the unit load changes, reducing energy consumption by 30% during low-load periods, and realizing "on-demand chlorine production".
As a benchmark project of Sino-Vietnamese BOT cooperation, Yongxin Coal-fired Power Plant pays more attention to local adaptation in the application of seawater electrochlorination technology. In view of the high temperature and humidity climate in southern Vietnam (annual average humidity > 85%), the equipment adopts 316L stainless steel shell and IP65 protection level design, and the electrode coating is added with tantalum to enhance corrosion resistance; the supporting backup power system can operate for 3 hours in case of power failure to avoid the rebound of biological pollution. The project also cooperated with local Vietnamese enterprises to establish an operation and maintenance center, trained professional and technical personnel, shortened the fault response time to less than 4 hours, and solved the lag problem of cross-border operation and maintenance.
Technical Value: Dual Gains in Environmental Protection and Economy
The popularization of seawater electrochlorination technology in Vietnamese power plants is reshaping the environmental protection and economic pattern of the local power industry. At the environmental protection level, this technology has completely replaced dangerous chemicals such as liquid chlorine and bleaching powder. The number of environmental pollution incidents caused by chemical leakage in Vietnamese coastal power plants has dropped from 12 in 2018 to 1 in 2023, and the water quality compliance rate in surrounding sea areas has increased to 98%. Taking a coastal power plant as an example, it reduces the annual liquid chlorine transportation volume by about 500 tons, which is equivalent to reducing 300 dangerous goods transportation risks, and the community's environmental satisfaction has increased from 65% to 92%.
The economic benefits are also significant. The raw material cost of electrolytic seawater chlorination is only 1/3 of that of chemical agent procurement. After the transformation of a 300MW unit power plant in Vietnam, the annual water treatment cost is saved by about 1.2 million US dollars; the long service life and low maintenance characteristics of the equipment further amplify the advantages. The electrode replacement cycle reaches 8 years, which is 50% longer than the traditional system, and the operation and maintenance cost is reduced by 40%. In addition, the improvement of heat exchange efficiency is directly converted into power generation benefits. Yongxin Power Plant has reduced the unit heat consumption rate by 1.2% through this technology, increasing annual power generation by about 15 million kWh.
At the policy level, this technology perfectly meets the requirements of "green power plant" construction in Vietnam's "National Power Development Plan by 2030", and has become a key indicator for power plants to obtain environmental certification. Data from Vietnam Electricity Group (EVN) shows that power plants using seawater electrochlorination technology can obtain a premium of 0.002 US dollars/kWh in the on-grid electricity price bidding, which further encourages the promotion of the technology.
Challenges and Prospects: The Localization Path in Technical Iteration
Despite the remarkable results, the application of seawater electrochlorination technology in Vietnam still faces unique challenges. The corrosion rate of high-salinity seawater to equipment is 3 times that of freshwater environment, and some power plants have problems of premature aging of electrolytic cell seals; the sudden increase of seawater turbidity during Vietnam's rainy season (May-October) leads to accelerated electrode scaling, requiring frequent cleaning to maintain efficiency. In response, the industry is breaking through the bottleneck through technological innovation - the new graphene-coated electrode increases the anti-scaling ability by 60%, and the self-cleaning electrolytic cell design extends the cleaning cycle from 1 month to 3 months, effectively reducing the maintenance intensity.
Bluewav has been committed to the development and application of seawater electrochlorination technology. In the future, the development of seawater electrochlorination technology will show three major trends. First, integration with renewable energy. The rise of coastal wind power and photovoltaic power stations in Vietnam provides green power support for the electrolytic system. A pilot project has reduced carbon emissions in the chlorination process by 75% through wind power supply; second, intelligent upgrading. AI algorithms combined with marine environment big data can predict the outbreak cycle of marine organisms in advance to realize "preventive chlorination"; third, localization of the industrial chain. Chinese enterprises cooperate with Vietnam to build electrode production bases, shortening the equipment delivery cycle from 3 months to 1 month and reducing costs by 20%.
From the Mekong Delta to the coast of the Beibu Gulf, seawater electrochlorination technology is injecting green momentum into Vietnamese power plants with the innovative logic of "circular utilization of seawater resources". This is not only a cross-border transfer of technology but also a microcosm of in-depth cooperation between China and Vietnam in the field of energy and environmental protection. As Vietnam's power industry transforms towards "low carbon, safety and efficiency", seawater electrochlorination technology will continue to play a core role, writing a new paradigm for the sustainable development of coastal power plants in Southeast Asia.
Bluewav's seawater electrochlorination systems have been successfully applied in Southeast Asian countries such as Vietnam, Thailand, Myanmar, and Cambodia, serving a wide range of fields including power plants, water treatment plants, and seawater desalination plants. With excellent performance and stable operation, they have won high praise and recognition from end customers.