View of the technical installations
required at Golfsteig’s Stephanposching
plant for using steam from a nearby
paper mill (photo: Gammel Engineering)
cheese dairy, which was laid in a second
step. "The greatest challenge here
was the route along a field path with
adjacent land belonging to a farmer,"
reports Zweier. "Although we were able
to negotiate a permit for the laying of
the pipeline, we were not allowed to
use the fields for building. In addition,
other pipelines were already running
under the dirt road, so that Gammel
had to work with special engineering
skills: Since a straight pipeline was required
for steam transport, the existing
gas and water pipes had to be laid in
a very confined space. For this purpose,
the two pipes were shifted sideways by
approx. 1.5 m to make room for a sawtooth
steam pipe for optimum drainage
of the two condensate pipes running in
opposite directions.
In addition to these on-site challenges,
the pressure loss in the longdistance
steam line also had to be taken
into account. While the overpressure in
the paper mill was 3.2 bar, only 2.5 bar
was available at Goldsteig. Since a lower
steam pressure would also have meant
carrying less heat and thus less condensate,
this loss had to be compensated.
Technology/IT ¦ IDM
This heat exchanger is used to produce clean steam out of the incoming steam
flow (photo: Gammel Engineering)
"We decided on a two-track tactic here,"
explains Zweier. "On the one hand, a
heat exchanger with a particularly large
exchange surface was installed to achieve
better heat transfer with almost no pressure
loss. On the other hand, the ground
pipe is double insulated with mineral fiber
and polyurethane foam which minimizes
heat loss to the ground". In addition, the
casing pipe is impact and break-proof as
well as resistant to chemical compounds
occurring in the soil. In order to be able
to detect possible leaks at an early stage,
control wires are incorporated into the insulation
layer, the signal of which is continuously
monitored.
Clean steam generator
and heating condenser
Finally, in a third and fourth construction
phase, the supply on the Goldsteig
site as well as the technical centre were
implemented so that the steam on the
dairy site could be safely transported to
the clean steam generator or the heating
condenser in the basement. Gammel also
planned the sophisticated object-specific
measurement and control technology.
The steam now passes from the district
heating pipeline via a pipe bridge to the
technical building of the dairy, where it
is converted into clean steam for production
processes and 95 °C hot water for
heating. This is ensured by a clean steam
generator with a capacity of 500 kg/h
and a heat condenser. Any condensate
produced in the process is returned to the
paper mill, where it can be used again as
feed water for steam generation. In this
way no heat and no steam is left unused.
"The great win-win effect of this steam
conversion is that the electricity generated
by Bayernwerk is additionally remunerated,
so to speak, because the residual
heat after the turbine is now used and a
corresponding CHP (cogeneration) bonus
is granted for this".
After final acceptance, the responsible
team of the Goldsteig cheese dairy
was very satisfied with the steam forming
concept. "Instead of investing in our
own boiler for heat generation, which in
turn would have meant up to 30 percent
higher emissions and additional radiation
losses, we are accepting longer pipes and
using the excess heat from the nearby
paper mill," explains Kiendlbacher. "This
allows us to generate the required heat
more cost-effectively and an efficient
heat cycle and energy partnership has
been established between the parties
involved". Although extensive coordination
with the paper mill and Goldsteig
was necessary, Gammel was able to implement
all requirements within the given
time frame. "It was a very constructive
and cooperative teamwork, with a result
we are all proud of. This lighthouse project
was therefore all the more fun for us
at Gammel", Zweier sums up.
June/July 2020 ¦ international-dairy.com · 31
/international-dairy.com
