Our pilot machine opens up new options for refining and testing our pulp technology,” says Marcelo Karabolad dos Santos, Head of Development for pulp drying machines. “We can run trials for customers, develop new products and simulate production parameters for new machines.”

The pilot machine is installed in Voith Paper’s Innovation Center in São Paulo. It is approximately 55 m long and 0.5 m wide and models the entire pulp manufacturing process from screening to cutting and baling. The complete line was designed with a focus on saving energy and increasing productivity.

Less energy. The vertical dryer section is not the only interesting part of the machine. The other sections consist of innovative yet already proven technologies where Voith has a lot of experience. The screening, for example, uses up to 30% less energy due to a new basket and rotor design. The MasterFormer is a wire former for pre-drainage followed by a double wire former with high tension. It removes a great amount of water and therefore allows a lower vacuum consumption and thus also saves energy.

The press section is largely based on the shoe press technology that has been very successfully used for a long time in conventional paper machines. The MasterFlex press with two shoe presses is able to work at very high pressures. Using eucalyptus, this brings a high solids content of almost 60% after the press and results in a lower steam consumption or higher production. In addition, it improves the runability of the machine causing fewer breaks due to high dryness after the 1st and 2nd press.

From horizontal to vertical. However, the technical revolution as such takes place in the dryer section. Unlike all comparable machines developed and built to date, the pulp in São Paulo runs through this dryer vertically, not horizontally.

In the patented process, the web is guided vertically by pulp guide rolls. Blow boxes installed between the guide rolls dry the web from both sides. The web is guided and kept stable only by the guide rolls and not sustained by the air flow. This means that unlike the horizontal process, the air flow is used in its entirety for drying, which substantially enhances the efficiency of the impingement drying.

Increased efficiency. The vertical Master- Dryer improves the runability of the machine because of shorter downtimes after a break. Karabolad dos Santos explains: “A vertical MasterDryer can be cleaned in minutes, whereas the conventional horizontal system might take several hours.” The reason for this is that in the horizontal dryer the broke pulp falls onto the blow boxes and is labor intensive to remove. In the vertical dryer, the pulp simply falls between the blow boxes onto the conveyor and then goes to the pulper. Finally, the MasterDryer allows zone control, which may optimize the drying process.

The pilot machine’s cutting technology, supplied by Pasaban in Spain, works with synchronized knives, a system that improves cutting quality and reduces both noise levels and vibration allowing higher speeds.

First customer. The pilot machine has been running since the beginning of 2012. There is already the first satisfied customer using the vertical drying technology. Since June 2012 a vertical dryer group has been operating very successfully at Lwarcel Celulose in Lencóis Paulista in São Paulo state.

And this system showcases a third advantage of this technology. The customer wanted to increase the drying capacity of the existing machine, but did not have enough space to install another horizontal dryer deck. This is where vertical dryers offer the benefit of just being tall but not long. Luís Künzel, General Director of Lwarcel Cellulose, is impressed: “During the entire rebuild phase, which took about six months, the existing horizontal system could continue to run. With the help of the vertical dryer, we are now in a position to increase drying capacity by 15%.” //