Biomass losses during short-term storage of bark and recovered wood

Storage of biomass is associated with problems like heat development, biomass losses, and reduction of the fuel quality. Certain processes such as biological- and chemical degradation are responsible for these storage problems. This master’s thesis was carried out at Vattenfall Research and Developm...

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Autor principal: Anheller, Martin
Formato: H3
Lenguaje:Inglés
sueco
Publicado: SLU/Dept. of Energy and Technology 2009
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Sumario:Storage of biomass is associated with problems like heat development, biomass losses, and reduction of the fuel quality. Certain processes such as biological- and chemical degradation are responsible for these storage problems. This master’s thesis was carried out at Vattenfall Research and Development AB and is aligned towards quantifying the biomass losses from short-term storage (1-2 months) of bark and recovered wood. The biomass was stored in outdoor piles during different seasons, campaign 1 (summer) and campaign 2 (autumn). Partial covering with tarpaulins of some of the piles were also investigated. The stored biomass was analysed for moisture content, ash content and heating value. The biomass losses that were based on the dry matter losses and reduction of the net heating value of the fuel were limited in the piles of recovered wood. The bark piles had higher biomass losses due to higher moisture content and smaller particle size distribution. Storage of moist bark in large piles leads to temperature development and subsequently a few percent losses in dry weight. The temperature development in the piles of recovered wood is limited and more dependent on ambient conditions. No effects of partial covering of the piles were found since the covering was most likely too small. It was found out that the method of quantifying biomass losses used in this report needs to be improved to be able to quantify small biomass losses during short-term storage, since it is not sensitive enough. The best way to store biomass at a heating plant for minimal fuel losses is under roof and with as low initial moisture content and large particle size distribution as possible.