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THE
COMPANY
INIZIATIVA AMBIENTE
is an Italian Consortium located in Parma established
for disposal of most of vaccine milk they producers
in the area (Reggio Emilla, Parma, Cremona and Mantova
provinces) which has recently built up a whey treating
plant.
Suppliers are small and medium size dairies producing
parmesan cheese in the above mentioned provinces. The
end product is powder whey that is to be sent to food
and livestock breeding industry. Absorbing capacity
is about 200.000-t/year whey.The plant operates continuously,
with production cycles of 8-10 hours, with time intervals
required for scheduled plant washing, for a total amount
of approx. 5000 hours/year. Total electric energy consumption
is about 5500 Mwh/year.
(
INIZIATIVA AMBIENTE S.Polo di Torrile (PARMA) )
THE
PROBLEM
Whey powder production
from milk whey is achieved in INIZIATIVA AMBIENTE through
different phases: pasteurisation, heating,concentration,
hot arm drying and final packaging (sacks).Concentration
is the most energy-consuming phase.
Taking into account whey volumes to be treated and concentration
levels implied in INIZIATIVA AMBIENTE ( dry substance
content is brought from about 6% up to approx. 36% )
it has a primary role in whey treating process economy.In
building up the new milk whey treatment plant, particular
attention was given to this phase and different solutions
were examined in order to optimise costs and whey treating
plant performance.
A traditional evaporating technology, based on the use
of multiple stages evaporator and vapour thermal-recompression
(product vapor temperature is increased mixing it with
high-pressure boiler produced live steam) would have
required a high fuel consumption with energy expenses
approx. 175.000 US$ per year.
It was also necessary to maintain steam production during
the entire production cycle, therefore with further
energy expenses; moreover, evaporators and thermal-recompression
system would have required a lot of space.
THE
SOLUTION
A Mechanical Vapor
Recompression (MVR) plant was chosen for milk whey concentrating
process.With this technology, milk whey vapour temperature
is increased by mechanical compression, by means of
a compressor driven by an electric motor, and re-used
as heat source during the evaporating process. Evaporation
is a self-supported process (steam power plant is required
only for start-up), so MVR allows also to eliminate
the need of high temperature steam during the entire
entire production process.
Two MVR evaporating units will be installed, 200 kW
compressor each, capable to treat 15 m3/hour whey each
and in increase the dry substance content from about
6% up to 36%.
Total MVR installed power is about 0.48 MW and specific
electric energy consumption is of about 14 kWh/t-evaporated
water.
INIZIATIVA AMBIENTE plant has been designed by Niro-Soavi
S.p.a.; elctrical motor-compressor units were supplied
by ABB.
RESULT
aims : ENERGY SAVINGS
Being a very efficient
technique for thermal energy recovery in concentrating
processes, MVR allowed INIZIATIVA AMBIENTE to achieve
high energy servings with respects to thermal technology:
about 40% overall energy savings were achieved.Environmental
benefits could also be obtained: approx. 67% primary
energy savings can be estimated replacing traditional
evaporating system with MVR system.Start-up times are
also reduced, with consequent production time and operating
costs benefits.
Moreover, space reduction was obtained: MVR plant dimensions
are about 1/5 of a traditional multiple, stage thermal
recompression plant of the same capacity.Smaller plant
dimensions also means a reduction in metallic mass and
therefore fewer amounts of detergent required for washing,
with lower running costs and environmental benefits.
Better end product quality could also be obtained with
MVR system, as product evaporation temperatures are
about 5oc lower than those required by a traditional
thermal process, which therefore results in food product
feature protection.
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