All Niro systems provide pre-heating and heat treatment to kill
bacteria, reduce energy consumption and ensure that the correct functional
properties are achieved in the feed concentrate.
The low residence
time, often down to as low as 6-10 minutes, provides the following benefits:
- Minimum heat load on product
- Short start-up and shut-down times
- Low product losses
- Reduced cleaning time and costs
MVR Evaporation (Mechanical Vapour Recompression)
For
applications where the availability of steam is restricted or expensive, the
MVR system is recommended. This system uses high-pressure fans to compress the
vapour generated by the evaporation to a higher temperature and return it to
the same effect. Excess vapour from this effect is either lead to a condenser
or utilized in a finisher.
The MVR evaporator can also be fitted with
the wrap-around separator that considerably reduces space requirements while
matching or even improving the high efficiency of the traditional tangential
separator.
The advantages of the MVR evaporator are:
- Low energy consumption. This applies to both heating and cooling
requirements as the plant produces cold condensate suitable for cooling
purposes.
- Recompression power supplied electrically thus reducing steam requirement
- Ease of operation. The fan allows for full and rapid control of evaporation
within the entire range of the plant without reconfiguration of the plant.
MVR
TVR Evaporation (Thermal Vapour
Recompression)
In multiple effect TVR evaporators the evaporative
energy in the first effect is supplied from a steam injector that compresses
vapour from one of the associated effects to a higher temperature.
The
heating medium in any subsequent effect is the vapour generated in the previous
effect. Vapour from the final effect is condensed by heating the incoming
product and in the condenser. The hot condensate can be reused for boiler water
and/or CIP liquid.
The choice between MVR and TVR depends on the local
prices of different energy sources, the possibility of using the condensate,
the depreciation of the capital cost (including capital cost of the building),
and the cost of product losses during cleaning.
TVR
Direct Contact Heating In the early 1980s it
was proved that even minimum residence time above 70°C had major impact on
product properties. Heating in indirect heaters proved to have too long and
uncontrolled residence time for many applications.
Niro's new direct
contact heating systems however heat the product instantly by condensing steam
directly in the product. The heating can take place with or without
regenerative steps depending on the energy costs and/or the required heating
duty and can be designed to give exactly the time/temperature combination
required by the product.
Today Direct Contact Heating is the worldwide
standard within the dairy industry.