Project description
Norske Skog operates two paper machines at the Bruck mill in Austria, producing publication and packaging paper. Two recent projects, completed between 2020 and 2023, are key for the mill’s future production. Paper machine 3 was converted into the production of packaging paper, and the new Waste to Energy (WTE) boiler K9 reduces fossil fuel use.
The projects are closely connected. Paper rejects from recovered paper and biogas from anaerobic treatment fuel the WTE boiler. The WTE boiler is now the main steam source for the mill, reducing natural gas use in the combined cycle power plant by 75%.
The implemented solution
The 50 MW bubbling fluidised bed (BFB) boiler was chosen for its 40 years’ experience in mill residues such as bark and sludge. It is the optimal solution for low-heating-value fuels such as paper rejects. The boiler is designed for the incineration of paper rejects, refuse derived fuels (RDF) and sludge. The full integration into the existing mill infrastructure (feedwater, steam turbine, power connection) helps to minimise the investment cost. However, it also added complexity to the project due to the limited space, with the installation being carried out during the mill’s full operation.
A state-of-the-art flue gas cleaning system includes cyclones for ash removal, dry cleaning with activated carbon and hydrated lime, flue gas condensation for heat recovery and a catalyst for NOx-reduction, ensuring low emissions. The flue gas condensation provides up to 10 MW for process water heating and district heating applications.
The key hurdles solved
The permitting process, including an environmental impact study, took three years.
Integrating the new project into an industrial site with a long history of production posed challenges, especially as the pandemic started just after the main boiler contract had been signed. Nevertheless, the project was completed on time and within budget.
Gas condensation provides up to 10 MW for process water heating and district heating applications.
Key Suppliers / Partners
- The mill itself – the project management.
- Valmet – the main supplier for the complete boiler delivery.
- Locally – the scope of the fuel storage, supply and the integration into
the mill infrastructure.
