PD leaflet: AlfaVap System0 pages

AlfaVap™ system
A cassette evaporator for high viscosity products
Applications
AlfaVap cassette evaporators are designed for concentrating
process liquids that contain dissolved and finely dispersed
proteins of animal or fish origin, such as:
• stickwater from fishmeal plants
• glue water from meat by-product plants
• fish extracts and bouillon products
• canning cooking water
• meat extracts and bouillon products
• fish or meat-based hydrolysate products
• fish silage products
• gelatin products
AlfaVap cassette evaporators are also supplied in food-grade
quality, which means that all inner parts can be effectively
cleaned by a CIP (Cleaning-in-Place) cycle. This is available
as an automatic program integrated into the controls of the
AlfaVap system.
Cassette evaporator design
AlfaVap cassette evaporators combine the state-of-the-art
thermal technology and know-how available from Alfa Laval
into very compact evaporator units, which come in
standardized models or can be customized to meet individual
requirements.
The AlfaVap system is available as a single-stage, two-stage
or three-stage evaporator – depending on the heating
medium, throughput or specific concentration demands of
the end product.
The modular AlfaVap skid concept includes all the main
components of the evaporator, such as one or more cassette
evaporator stages with circulation pumps, vapour condenser,
vacuum pump station and concentration monitoring
equipment. Each cassette stage is arranged within a frame,
which can accommodate different numbers of cassettes. This
means that any moderate increase of throughput is possible
without additional installation work.
The electrical control and monitoring panel can be placed
alongside the evaporator or more centrally in a general
control room.
Cassette evaporator operation principle
The AlfaVap cassette evaporator works on the basis of the
so-called rising film principle, partly enabled by forced
circulation. However, unlike other evaporators based on this
technology, the AlfaVap system conducts practically all of the
evaporation within the cassettes. These thus serve almost as
foam-filled boiling chambers, with very high velocities of the
evaporating medium.
The cassettes are equipped with special corrugated surfaces
that create a high rate of turbulence throughout the entire
product chamber, which results in high heat transfer
coefficients. This high turbulence and the rising foam film also
eliminate wetting problems and dead spots, which again
substantially reduces any tendencies to fouling. This means
longer operation periods between cleaning cycles.
Evaporation step by step
The following step-by-step description is based on a twostage
evaporator, but the basic principles also apply to threestage
evaporators, or can be transferred to single-stage
evaporators.