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Research article - Peer-reviewed, 2018

Antioxidants as additives in wood pellets as a mean to reduce off-gassing and risk for self-heating during storage

Arshadi, Mehrdad; Tengel, Tobias; Nilsson, Calle


Spontaneous self-heating and off-gassing of wood pellets during storage is well-recognized problem. The reason for the phenomena is be autoxidation of fatty/resin acids in the pellets material. Two antioxidants, TBHQ (tert-Butylhydroquinone) and PG (propyl gallate), have been used as additives during pellets production in order to investigate how effective these antioxidants are in blocking autoxidation. Off-gassing of volatile aldehydes, CO and CO2 from wood-pellets and depletion of O-2 during storage at room temperature in two different scales of closed storage systems were investigated and antioxidant fortified pellet batches and a reference batch without additive were compared. The results show that TBHQ is an efficient antioxidant at a low concentration (0.5%) in blocking autoxidation of fatty/resin acids in wood pellets. The CO emissions are reduced between 72 and 90% depending on the pellets temperature. Some of the fatty acids are almost intact in the samples with TBHQ compared to reference sample; showing that TBHQ blocking degradation by autoxidation of those fatty acids. For PG, autoxidation has not been blocked. The total amount of emitted aldehydes are 77% less than in pellets made with antioxidants as compared to the reference pellets, showing that TBHQ is acting as inhibitor in the autoxidation processes.


Autoxidation; Aldehydes; CO off-gassing; O-2 depletion; Fatty acids; TBHQ; PG

Published in

Fuel Processing Technology
2018, volume: 179, pages: 351-358

Authors' information

Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology
Tengel, Tobias
Swedish Defence Research Agency (FOI)
Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology

UKÄ Subject classification

Other Chemical Engineering

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