Pilot Evaporator

Product overview

Used-GEA Wiegand GmbH Falling Film Evaporator, Double Effect Direct Heat Single Pass.  Capacity is rated at 600 kg/hr @ 10% ts concentrating to 65% ts.  Previous use on skim milk 9% ts to 36% ts at 1,350 lph.

Design
A vertical shell-and-tube heat exchanger, with a laterally or concentrically arranged centrifugal separator.

Operation
The liquid to be concentrated is supplied to the top of the heating tubes and distributed in such a way as to flow down the inside of the tube walls as a thin film. The liquid film starts to boil due to the external heating of the heating tubes and is partially evaporated as a result. The downward flow, caused initially by gravity, is enhanced by the parallel, downward flow of the vapour formed.

Residual film liquid and vapour is separated in the lower part of the calandria and in the downstream centrifugal droplet separator. It is essential that the entire film heating surface, especially in the lower regions, be evenly and sufficiently wetted with liquid. Where this is not the case, dry spots will result that will lead to incrustation and the build-up of deposits.