Epsilon Open Archive

Abstract

Terminals and log-yards are becoming increasingly important in Nordic forest supply chains because of the need to support the rising production capacity of pulp mills and heat and power plants. Most modern terminals and log-yards handle multiple assortments, must accommodate multiple incoming and outgoing modes of transport, and have multiple storage areas. This complexity makes it challenging to find ways of increasing their efficiency. The design of more efficient terminals will therefore require a detailed understanding of the current state of forest terminals and the activities that occur within them. The overall objectives of this thesis are thus to provide a general overview of the current state of forest biomass terminals in Sweden, to determine the scope for upgrading biomass fuel at terminals, and to find reliable ways of analyzing log-yard and terminal performance. To achieve these aims, data were gathered by means of surveys, questionnaires, time studies, analyzing fuel-chip quality, and discrete-event modeling.

The most pronounced differences were observed between terminals with areas of < 5 ha and those with areas of > 5 ha. Terminals of < 5 ha accounted for 65% of the country’s total terminal area, and terminals of < 2 ha handled half the country’s total terminal biomass output. Comminution activities were performed at 90% of all terminals, creating opportunities to add value to the processed material. By screening fine particles, it was possible to reduce the average ash content of the processed assortments to 0.66-2.17% (corresponding to a 20-31% reduction in total ash content). Screening could thus be used to divide chipped material into various quality classes suited for different applications with different price points. Models developed using production data for log-yards reliably predicted real-world outcomes over the studied time period and highlighted the importance of gathering relevant real-world data for meaningful analysis and improvement of log-yard operations. This thesis provides an overview of Sweden’s forest terminals, energy assortment quality, and potential operational improvements. The discrete-event models presented here are helpful tools for understanding log-yard operations and supporting decision-making by forest businesses.