Rottneros, Sweden, has started up a new high consistency bleaching system according to plan at one of its two pulp mills in Sweden. The startup was smooth and the 48 hr. test run was approved.

The bleaching system is the first step in a larger rebuild project, called Agenda 500, at the mill. The long term goal is to increase both availability and total production volume of Rottneros’ two pulp mills to reach a capacity of 500,000 metric tpy.

"The check-out and startup of the plant went beyond expectation, as you want it to do, and we have already been able to lower the peroxide charge. We are very satisfied with the equipment we have bought and it looks promising for the future. We will now continue to ramp up production," said Jan Viper, project manager at Rottneros mill. 

"This has been a great project, well organized by Rottneros. Having all instruments and surrounding connections prepared made a fast startup possible. Commissioning took only three days. When we started the project, the time table was very tight, but in the end we were actually ahead of schedule. This is the first installation of the FKC screw presses in Europe, so this is a good reference case for us," said Lars-Olof Larsson, project manager at Valmet.

 

 

In the photo above part of Valmet's team during startup shows pulp samples before and after the new bleaching tower. In front of the screw presses (l-r) are: Zhi Ping, technical sales manager; Lars Spjuth, startup manager; and Kim Rökman, service engineer.

 

In bleaching, the brightness of the pulp in a mechanical pulping line is increased by peroxide. The new bleaching system consists of a chemical mixer and a bleaching tower, two washing stages with screw presses, and medium consistency pumps. Before the bleaching tower, the pulp is washed and pressed to a high consistency. Bleaching at high consistency gives an effective bleaching reaction and less chemicals are needed.

Rottneros produces market pulp and has an annual production capacity of just under 350,000 metric tons of pulp, produced at two mills in Sweden. In 2014 Rottneros employed around 250 people, the majority in Sweden, and had sales of approximately SEK 1.5 billion.