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)