Any conventional multi effect evaporation process consists of a combination of falling film and forced circulation evaporator columns, wherein water content in spent wash is reduced up to 40% and balance is fed either to a boiler or for composting.
Solid contents in inlet feed of evaporation, if is not from Pre-Ferm – where sludge is removed already – can cause greater challenges in evaporation with increase in scaling.
Conventionally in falling film evaporators, the frequency of cleaning increases considerably because of two things
a. Inadequate design of distribution plate which fails in forming a consistent film
b. The low pump pressure which lets the solid contents rest on the tube.
These two defects, increase the formation of solidified feed and in turn not only cause the scaling in the tubes but also choke the distribution plates. All resulting the cleaning of these in as less as every 10 days.