Thermal Vapor Recompression Evaporators

Swenson thermal vapor recompression (TVR) evaporators use a thermocompressor to reduce the steam required per pound of evaporation—ultimately reducing energy consumption and saving costs.

Benefits of Thermal Vapor Recompression Evaporators

  • Significant energy and cost savings
  • Ideal for low boiling-point rise liquids

How Thermal Vapor Recompression Evaporators Work

To reduce energy consumption, water vapor from an evaporator is entrained and compressed with high pressure steam in a thermocompressor so it can be condensed in the evaporator heat exchanger. The resultant pressure is intermediate to that of the motive steam and the water vapor. A thermocompressor is similar to a steam-jet air ejector used to maintain vacuum in an evaporator.

Only a portion of the vapor from an evaporator can be compressed in a thermocompressor with the remainder condensed in the next-effect heat exchanger or a condenser. A thermocompressor is normally used on a single-effect evaporator or on the first effect of a double- or triple-effect evaporator to reduce energy consumption. Like mechanical recompression, thermal recompression is more applicable to low boiling-point rise liquids and low to moderate differential temperatures in the heat exchanger to minimize the compression ratio.

The double-effect evaporator with thermal recompression requires 33% less steam than the conventional double effect. In essence, the steam usage for the double effect with thermal recompression is comparable to that of a triple-effect evaporator.