An energy saving of more than 50 percent of the jet blast could
represent significant savings for many tissue manufacturers. Several
participants at the Tissue Maker conference promptly began asking
questions, such as whether the technology could also be used on
existing machines. “We have to determine that on a case-by-case basis,” answered
Karl-Johan Tolfsson, Manager of Metso Tissue Technology Center in
Karlstad. “It depends on whether the machine has sufficient space to
fit the turbine.”
No disruption to operations
The turbine is placed just after the headbox and forming section, and
captures the jet blast from what is known as a Banki turbine, whereby
water passes through the turbine and generates energy at both the
infeed and outflow phases. The Banki turbine is often used in
small-but-fast water flows and has the advantage of high reliability.
The turbine is connected to a generator and the electricity produced is
then passed back to the machine’s drive units.
The jet blast is led to the turbine through a guiding plate, which can
be reset so that the water flows past the turbine while operation
continues normally. The design engineers have thus also created a
solution that enables the maintenance of the turbine without any
disruptions to production.
Tissue Maker 2012 was held in mid-September in Karlstad. A considerable
amount of development has taken place at Metso’s Tissue Technology
Center in Karlstad, the place where the pilot machine is located and
where the technology was tested, and where the project’s target of
recycling more than 50 percent of the energy from the jet blast was
achieved.
The Banki turbine was chosen in consultation with development engineers
at Vattenfall, which uses the technology in unmanned power plants where
electric power is generated in minor watercourses.
To harness the maximum amount of energy, it is vital to remove as much
of the air as possible that has been mixed with the water in the
forming section. This is one of the purposes of the guiding plate and
Metso’s pilot tests have indicated a removal of approximately 80
percent of the air from the water. (Greenindustry and Papernet)
BREAKING