In the production processes of high-water-consuming industries such as chemical engineering, power generation and steel manufacturing, a large amount of saline wastewater is continuously produced, including acidic and alkaline wastewater, and circulating cooling discharge water, etc. The total salt content of such wastewater is usually no less than 1%. The main components include chloride ions, sodium ions, calcium ions and sulfate ions, etc. Traditional physical and chemical as well as biochemical technologies have poor performance in desalination, making it difficult to achieve the recycling and reuse of saline wastewater. Direct discharge would also have adverse effects on the receiving environment and lead to serious waste of water resources. The emergence of MVR technology for treating saline wastewater provides a new solution to break this predicament.
The bottleneck in the treatment of saline wastewater from high-water-consuming industries
Chemical, power and steel enterprises, as major water consumers in industrial production, discharge saline wastewater with complex components and high salt concentrations. Due to the presence of a large amount of soluble salts in the wastewater, conventional physical-chemical treatments such as sedimentation and filtration can only remove suspended impurities but cannot effectively reduce the salt content; biochemical treatment technologies, due to the high salt environment, will inhibit microbial activity, resulting in a significant decline in treatment efficiency. This treatment bottleneck leaves enterprises either facing the problem of waste from wastewater that cannot be reused, or bearing environmental pressure due to non-compliance with discharge standards. Therefore, an efficient desalination treatment technology is urgently needed.
The technical principle and core advantages of the MVR method for treating saline wastewater
The working mechanism of the mechanical vapor recompression technology
The core of the MVR method for treating saline wastewater is the mechanical vapor recompression technology. This technology recovers and utilizes the secondary steam generated during the evaporation process by introducing a steam compressor or compressor fan. Unlike traditional evaporation techniques, the MVR system does not require continuous supply of new steam. It only needs to consume a small amount of electrical energy to drive the compressor to operate, thereby increasing the temperature and pressure of the secondary steam, allowing it to re-enter the evaporation process as a heating source, significantly reducing energy consumption and demonstrating remarkable energy-saving and environmental protection characteristics.
A complete MVR evaporation system is mainly composed of a preheater, an evaporation heat exchanger, a compression fan, a circulating water pump, a vacuum pump and a control system. Among them, the compression fan, the conveying pump, the circulating water pump, the condensate water pump, the discharge pump and the vacuum pump together form the power core of the system, ensuring the stable circulation of wastewater during evaporation, separation and condensation processes. The various equipment work collaboratively to achieve efficient treatment of the entire process from the entry of saline wastewater into the system to the discharge of concentrated liquid and the recovery of condensate water.
The application value and development prospects of MVR technology in the treatment of saline wastewater
The key to solving the problem of treating high-salinity wastewater
The technical advantages of mechanical vapor recompression for treating high-salt wastewater make it highly applicable in the field of industrial wastewater treatment. For wastewater with a total salt content of no less than 1% and rich in components such as chloride ions and sodium ions, the MVR system can achieve the separation of salt and water through efficient evaporation. The treated condensate water can meet the standards for recycling and reuse, while the concentrated liquid can be further subjected to reduction or solidification treatment, fundamentally solving the problems of poor desalination effect of conventional technologies and serious waste of water resources.
Technical Optimization and Future Trends
Currently, the core of treating saline wastewater using the MVR method lies in improving the performance of the
evaporator. By using corrosion-resistant materials such as stainless steel, duplex steel + titanium, it can effectively resist the erosion of high-salt wastewater. At the same time, before treating the wastewater, softening treatment of the incoming water is carried out to avoid device scaling during long-term operation of the system, ensuring the stable operation of the MVR system.
With the increasingly strict environmental protection industry policies, the reduction and even zero discharge of saline wastewater has become an inevitable trend. The MVR saline wastewater treatment process, with its features of energy conservation, high efficiency and stable operation, will have an expanding application scope. In the future, with the continuous iteration of technology, the MVR system will further improve in terms of energy recovery efficiency and automation control level, and will become one of the core technologies in the industrial field for realizing wastewater resource utilization and promoting green production.
Jinkebotong Environmental Protection Technology (Jiangsu) Co., Ltd