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Detailed introduction/parameters/applications/functions/maintenance of forced circulation Single-effect MVR falling film evaporator
The forced circulation single-effect falling film MVR evaporator is a high-efficiency and energy-saving evaporation device that combines mechanical vapor recompression (MVR) technology with forced circulation falling film evaporation. It is widely used in the concentration of high-salt wastewater, purification of chemical solutions, and treatment of heat-sensitive materials.
Structure and Principle: The equipment mainly consists of a falling film heating chamber, a gas-liquid separation chamber, a steam compressor, a forced circulation pump, a film distributor, and a vacuum system. The preheated liquid enters the top of the heating chamber and is evenly distributed on the inner wall of the vertical heat exchange tubes by the film distributor, flowing downwards in a thin film along the tube wall. The outer side (shell side) of the tubes is heated by steam, and the liquid film inside the tubes rapidly boils and evaporates. After the gas-liquid mixture enters the separation chamber, the secondary steam is adiabatically compressed by the steam compressor, raising its temperature by 5–15°C. It is then sent back to the shell side of the heating chamber as a heat source, releasing latent heat and condensing into water. The concentrated liquid is forced back to the heating chamber by the circulation pump to continue circulating until the target concentration is reached, at which point it is discharged.
The Role of Forced Circulation: Traditional falling film evaporation relies on gravity and pressure differential to form the film, which can easily lead to dry walls and scaling blockage under high concentration, high viscosity, or scaling conditions. Introducing a forced circulation pump allows for precise control of the liquid film flow rate within the pipe, enhancing the turbulent scouring effect, significantly inhibiting scaling and crystal deposition, while ensuring a stable liquid film formation even at low flow rates. This expands the adaptability of the falling film process to high-concentration liquids.
Technical Advantages: The single-effect structure is simple, eliminating the need for pressure gradients and complex heat balance control between multi-effect processes. Combined with MVR technology to recover the latent heat of secondary steam, the overall energy consumption is only 20%–35% of traditional multi-effect evaporation. The falling film method has a high heat transfer coefficient and short material residence time (several seconds to tens of seconds), making it particularly suitable for heat-sensitive substances; forced circulation gives it the ability to treat wastewater that is prone to scaling, high in salinity, and high in concentration. This equipment has significant energy-saving and operational stability advantages in zero-discharge wastewater treatment, high-salt mother liquor concentration, and valuable solute recovery. |
