Recovered fibres are one of the main raw materials for modern papermaking. A foreseable scenario for the recycled fibre based industry involves the expansion of the raw material base to highly mixed sources. At the same time, recycled paper will need to expand in the domain of virgin fibre products.
This development requires new process technology to recycle less expensive raw materials into improved products, with leaner production and lower energy consumption. Two EcoFracSmart projects have been working to make this vision prossible.
The first EcoFracSmart project started in 2002, with five partners and financial support by the Swedish Energy Agency. Two Swedish recycled paper mills, a small innovation company and Innventia tested a new stock preparation concept for recycled fibre lines. The first assessment showed that savings on energy could be as high as 50% for some of the most energy intensive operations.
The basic concept in the process is to separate the incoming raw materials according to their potential quality. Impurities are extracted as early as possible in the re-pulping process and energy intensive treatment are restricted to the fibre fractions that requires special processing.
Phase-contrast micrograph of a recycled fibre furnish.
In the second EcoFracSmart project we tested the first stages in the process in the stock preparation line of a Swedish paper mill. Moreover, we evaluated hydrocylone fractionation with selective refining and dosage of chemicals in the FEX pilot scale papermaking facility. Here, the project consortium expanded to seven partners: Innventia, Smurfit Kappa, Holmen Paper, Noss, Lyckeby Industrial, Läckeby Water and JLR Pulping Systems.
The trials confirmed the edvantages that the EcoFracSmart process would give. Such a plant would have fewer process steps and be more compact and smoother to operated.