ICAR AIEEA PG 2024 - Dairy Technology

Modern dairy falling film evaporators equipped with Mechanical Vapor Recompression (MVR) utilize an 'Integrated wrap-around vapor separator' built tangentially around the lower base of the calandria. This compact design eliminates long external ducting, minimizes vapor pressure drops before the fan/compressor, and reduces overall plant footprint.

In vacuum evaporation systems (such as dairy vacuum pans), the primary creator and maintainer of vacuum is the Condenser (barometric or surface condenser). When large volumes of water vapor are rapidly condensed into water, the specific volume collapses by ~1600 times, creating and sustaining a deep vacuum. The vacuum pump only removes small traces of non-condensable air leaking into the system.

An open pan evaporator boils milk at atmospheric pressure ($100^\circ\text{C}$), suffering massive convective and radiative heat losses and has a steam economy of less than 1.0 (it requires 1.1 to 1.2 kg of steam per kg of water evaporated). Vacuum pans and multiple effect evaporators utilize lower boiling points and reuse secondary vapor (steam economy reaches 2.0 to 5.0+), consuming far less steam.