Kostnadseffektiv och hållbar lagring av flisad skogsråvara och fasta biprodukter

The project aims to evaluate cost-effective, sustainable and fireproof management methods of unprocessed forest residues from the forest industry. Extensive industrial-scale storage trials were conducted within the project, from south (Småland) to north (Norrbotten). These trials reflect both a coastal and inland climate and seasonal variations. Two main methods for increasing storability were evaluated; coverage with different cover materials and sieving the biomass, which aims to partly increase the fuel quality by reducing the amount of fines in the material. The study included seven different work packages, including storage studies, production and cost studies for screening equipment, cost studies for terminal management, material self-heating potential, off-gassing during storage, temperature development and substance losses, and sustainability aspects in implementing the various methods. Overall, the evaluated methods lead to significantly better storage. Screening is the method that has led to the best storability, and results from the various studies have shown that the economic value of the biomass is about 20 % higher in sieved material after storage compared to unsieved. At the same time, the studies show that both covering and sieving lead to lower temperatures within piles, i.e. reducing the risk of selfignition and that off-gassing from the piles decreased. The screening, however, entails a cost corresponding to about 10 % of the economic value, but these findings were based on small diesel-powered mobile units. This cost will likely decrease using stationary electric powered equipment. Increased storability through sieving does not only mean obtaining a homogeneous fuel of higher quality, lower off-gassing and energy saving during the actual storage. It entails conditions for more cost-effective and sustainable fuel handling throughout the entire supply chain from forest to industry. Implementation of a storage strategy aimed at increasing the storability of fuels would affect all steps in the supply chain, such as even machine use over the year, lower production costs, more efficient transport, increased profitability for fuel producers, better access to materials, improved conditions for fuel production facilities that can use electric equipment. The latter could lead to safer and cheaper storage, reduced risk of self-ignition, safer fuel deliveries, better monitoring of fuel quality and an adaptation based on the customer's demand. In addition, these facilities could handle, fractionate, sort and control several different types of material streams for different purposes and could be considered nodes/biohubs within several different types of handling chains.