Schneider Electric Schneider Electric

Case Study
Lactose – Whey profitable
A new lactose-recovery facility at Morrinsville’s Tatua Dairy Company is
delivering multiple benefits to the organisation. The process uses high-pressure
filtration – Schneider Electric’s technology optimises its energy consumption
and simplifies its control.
Lactose is a simple sugar found in milk and
a major component of whey. Traditionally
considered an inconvenient by-product of milk
processing (and part of the waste stream), today
it is widely used for infant milk formulas and as a
supplement in food and confectionery.
In fact, lactose is so popular that dairy companies
now find it commercially viable to recover it and
on-sell it to third party manufacturers. Recovering
it also minimises a dairy company’s waste stream,
significantly reducing its environmental impact.
Overall, a classic win-win solution.
Tatua’s new lactose plant has been built on the
site of the company’s previous food manufacturing
facility. With the completion of a new food
manufacturing facility (in 2011), the old building
was demolished to make way for the lactose plant.
The new building will also house a new hydrolysis
plant (scheduled for completion in 2013).
The principle behind lactose recovery, says the
company’s projects engineer, Ben Wright, is
filtration. “Effectively we force the milk through an
ultra-fine membrane filter under high pressure. To
achieve the right flow rate and pressure we use a
range of pumps, including some very large ones.”
Auckland’s GEA Process Engineering, specialists
in membrane filtration technology, designed
and built the plant. It is fully-automated and runs
24/7. A single Schneider Electric Quantum PLC
oversees the process, distributing the control via
multiple racks with hundreds of I/O.
Hamilton’s Intelectric did the electrical installation
and Auckland’s Macro Automation programmed
and commissioned the control technology. It’s
all orchestrated via an Ethernet network which
Wright says allows for rapid communication with
the SCADA system, giving operational crew more
(and better) information to make decisions.
Multiple Schneider Electric Altivar 71 variable
speed drives control the large pumps, while a
range of Altistart soft starters and TeSys directon-line
starters are used on others. “Apart
from the energy efficiency benefits of using this
technology,” says Wright, “it also helps us to meet
our community responsibilities. The electrical load
at start-up is significant – the last thing we want is
to leave Morrinsville in the dark!”
Schneider Electric legacy
Tatua’s electrical foreman Peter Cook has worked
for the company for some 20 years, and says
Schneider Electric has an extensive track record
at the site. “The legacy includes many of the early
Modicon 800 series PLCs – and they’re still in
use. A major advantage of using a single source
supplier for the control technology is the common
protocol – even though the new Quantum PLC is
a vastly different beast to the earlier generation
technology, they can still communicate.”
Power supply
The new plant significantly increased the site’s
electrical load – and it will rise even further when
the new hydrolysis plant comes on stream. That’s
required the installation of a new 11kV transformer
and Schneider Electric 11kV switchgear.
The entire site has also benefitted from the
introduction of a new dedicated 33kV line which
will improve reliability of supply.
Tatua is one of New Zealand’s oldest dairies
and will celebrate its centenary in 2014. The
installation of the Schneider Electric technology,
says Cook, offers an element of future-proofing.
“As is evident from the existing infrastructure,
knowing that the equipment can easily be
incorporated into any future developments offers
peace of mind.”
Schneider Electric News December 2012 7