Ideas - Siemens

Hot standby SIMATIC S7400 PLCs, SINAMICS G150 variable frequency drives and EFF1 energy saving motors: notable features of the dryer control
system.
Heinrich Bertl, Commissioning Manager ,
Andritz and Ganasa Pouvaragamurthy, Siemens,
standing in front of the Changi Water
Reclamation Plant Phase 1, which covers 34
hectares and has a treatment capacity of
800,000 cubic meters per day
The used water treatment process is an
extensive one, involving all manner of sedimentation
tanks, bioreactors, anaerobic
digesters, and the sludge drying comes
right towards the end.
Essentially, the drying system acts to further
remove moisture from the sludge
produced by the upstream treatment processes,
such that sludge bulk is greatly reduced
and is much easier to handle, as it
transforms into high-grade granulate, or
pellets, that can be beneficially used for
agriculture or even as a secondary energy
source.
The Andritz Drum Drying System (DDS)
centers around a triple-pass drum (three
concentric cylinders revolving around a
joint axis) where the sludge is dried by
convection to a degree such that less than
10 percent residual moisture remains.
Five such drums are used at the CWRP.
PROFIBUS performs
PROFIBUS being mandatory for all CWRP
equipment packages was a welcome specification
item for Heinrich Bertl, who
was able to claim a number of years’
knowledge and experience of working
with the European-developed fieldbus
network technology.
The next step, then, was to find a supplier
of the control systems, drives, motor
starters, and motor control centers
that were required for the drying system.
And that’s when he turned to Siemens.
“The major factor was Siemens’ PROFI-
BUS expertise,” says Bertl, who also mentioned
some 30 years’ previous experience
working with Siemens in Europe
as another reason for the selection decision.
“This is the largest dryer that we
have ever manufactured and it is
the biggest in the world.” - Andritz
12 ideas singapore | 2008