MVR forced circulation evaporator

1. Working principle

Preheating Stage: The feed liquid first enters the preheater via a feed pump, exchanging heat with the condensate generated within the system to raise its temperature.

Evaporation and Concentration: The preheated feed liquid enters a forced circulation evaporator, circulating within it via a circulation pump. The feed liquid is heated in the heat exchange tubes of the evaporator, generating secondary steam, while the feed liquid is concentrated.

Steam Compression and Reuse: After exiting the evaporator separator, the secondary steam enters the compressor for compression. The compressed secondary steam has increased temperature and pressure, and its enthalpy increases. It is then returned as heating steam to the heating chamber of the evaporator to continue heating the feed liquid.

Condensation and Circulation: The heating steam condenses into condensate in the shell side of the evaporator and is discharged from the system. The condensate can be recycled, further improving the system's thermal efficiency.

Automation Control: The entire system is automated through a PLC control system, which monitors parameters such as temperature, pressure, and flow rate in real time to ensure stable system operation.

2. Structural Features

The main components of an MVR forced circulation evaporator include:

Heater: Typically a shell-and-tube heat exchanger, with material in the tube side and steam in the shell side. Multiple baffles in the shell side increase turbulence and enhance heat transfer.

Separation Chamber: A vertical unit that separates vapor and liquid, facilitates material settling, and promotes crystal growth during evaporation.

Forced Circulation Pump: Mostly an axial-flow pump, suitable for high-flow-rate, low-head applications. It increases the material flow rate within the evaporator, effectively preventing scaling inside the tubes.

Compressor: Typically a Roots-type or centrifugal compressor; the specific choice depends on the evaporation rate and process requirements.

Filtration System: Used to remove impurities from the secondary steam, ensuring steam purity.

3. Advantages and Applications

The MVR forced circulation evaporator offers the following advantages:

Energy Saving and Rapid Operation: By recovering the latent heat of the secondary steam, energy consumption is significantly reduced, resulting in low operating costs.

Anti-scaling design: The forced circulation pump creates high-speed flow of material within the evaporator, generating turbulence and effectively preventing scaling.

Wide applicability: Suitable for processing high-viscosity, easily crystallizing, easily scaling, or solid-containing materials.

High degree of automation: Automated operation is achieved through a PLC control system, reducing manual intervention.

MVR forced circulation evaporators are widely used in chemical, food, pharmaceutical, seawater desalination, and industrial wastewater treatment industries.