Focus On Steam Compressors
-
About Us
-
Applications
-
Application of MVR Evaporators in the Treatment of High-Salinity Wastewater
High-salinity wastewater arises from a wide range of sources; industries such as chemicals and pharmaceuticals generate substantial volumes of highly saline, high‑concentration organic wastewater during production. These effluents are chemically complex, with elevated salt content and high organic‑matter concentrations, making direct biological treatment difficult. For example, monosodium glutamate (MSG) production wastewater primarily originates from the fermentation broth remaining after MSG extraction, the mother liquor discarded following concentration and crystallization, and various wash and disinfection streams. Typically, 15–25 tons of wastewater are discharged per ton of MSG produced, containing inorganic salts, antifoaming agents, colorants, urea, various organic acids, and less than 1% of other amino acids. Molasses‑based alcohol wastewater is generated during the fermentation of molasses—a byproduct of sugar factories—to produce ethanol. After distillation, the resulting stillage—containing alcohol—is discharged as wastewater. When released into water bodies, such effluents deplete dissolved oxygen, degrade water quality, and severely compromise the ecological and utilitarian value of aquatic environments. Among industrial water pollutants, black liquor from papermaking accounts for a significant share. At present, only a small number of large‑scale kraft pulp mills employ methods to concentrate and incinerate black liquor for alkali recovery; by contrast, most plants discharge untreated black liquor directly into rivers and streams, leading to widespread pollution.
The environmental impacts associated with low‑discharge, high‑salinity wastewater necessitate the removal of pollutants from saline effluents. Common treatment approaches for such wastewater include: biochemical treatment using halotolerant bacteria, evaporation and concentration via conventional evaporators, desalination by membrane technologies, and electrochemical desalination. However, the toxic and inhibitory effects of high salinity pose significant challenges to biochemical processes; traditional evaporative systems are costly to operate and suffer from low energy efficiency; membrane‑based systems are expensive, prone to fouling and contamination, and generate concentrated brine that is difficult to manage; and electrolysis often proves impractical due to the presence of organic compounds. Consequently, conventional wastewater treatment methods exhibit notable limitations—demanding stringent operating conditions, incurring high costs, failing to remove salts, and yielding unsatisfactory results. As a result, the advanced treatment and remediation of this type of wastewater has become one of the key research priorities in the field of environmental protection.
With current human technology, the most effective approach for treating high-salinity wastewater is to use an MVR evaporator. MVR evaporation equipment can separate and treat salts in solid form, achieving low‑emission outcomes, while the resulting solid crystals can be recovered and reused.
The MVR evaporator comprises a steam compressor, plate heat exchanger, heat exchanger, evaporator, gas–liquid separator, and crystallizer. The steam compressor serves as the core component of the MVR evaporation system. This system is equipped with a fully automated PLC control program, eliminating the need for manual operation. The technology offers distinct advantages in treating high-salinity wastewater, including efficient evaporation, effective crystallization, and significant energy savings. The operating principle is as follows: the feed liquid enters through the inlet, is preheated to the required temperature in the plate heat exchanger, and then is pumped by the feed pump to the heat exchanger for further heat exchange. Afterward, it passes through the gas–liquid separator for vapor–liquid separation; the vapor is directed to the steam compressor, while the liquid stream is circulated via a forced‑circulation pump back to the heat exchanger. Following circulation, the concentrated liquid is discharged by the concentration pump. Meanwhile, the condensate from the heat exchanger is pumped by the condensate pump to the plate heat exchanger for recirculating heating.
The core technologies of an MVR evaporation and crystallization system lie in the steam compressor, the MVR evaporator–crystallizer, and automated control systems.
MVR schematic:
The energy-saving principle of MVR lies in:
(1) Electric heating is used in place of fresh steam heating, with low power consumption;
(2) The secondary steam generated during evaporation is compressed and fully utilized;
(3) Low steam losses within the system;
(4) The waste heat from the condensate and the concentrated liquid is used to perform heat exchange with the feed solution.
(5) The non-condensable gas is used for heat exchange with the original liquid;
(6) The compressor motor employs variable-frequency speed control.
MVR system features:
(1) Clean energy, high thermal efficiency, low power consumption, and minimal pollution.
(2) Industrial wastewater achieves “low discharge” levels that meet national emission standards.
(3) Integrated multi-functionality, reducing manufacturing costs.
(4) It has a broad range of applicability to materials awaiting processing.
(5) Low-temperature evaporation and ambient-temperature evaporation (non-standard, not based on pressure vessel design principles).
(6) It can discharge material continuously or intermittently. It features a high degree of automation and low operating costs.
(7) High degree of automation and low operating costs.
(8) Small size and high mobility.
MVR Cost-effectiveness:
Cost comparison per ton of evaporated water
(Based on steam at RMB 200 per ton and electricity at RMB 0.7 per kWh)
Keywords:
Other Information
Applications of Turbovap High-Speed Direct-Drive Steam Compressors Across Multiple Industries
Contact Us
Hotline
Address
No.198, Jinwu Rd, Liyang 213300, Jiangsu, China