Organic compounds released in fluidized-bed drying of peat, bark and lignite

Abstract

Organic compounds released in peat drying in a laboratory fluidized-bed reactor were analyzed by chromatographic methods in order to evaluate process operational and environmental aspects. For comparison, pine bark and lignite were also studied. Using steam as fluidizing gas, the release of condensable organic compounds comprised 2% and 25% of peat, calculated on a dry ash-free basis, when drying peat for 0.5 s at 190 and 350 °C, respectively. The corresponding release of noncondensable gaseous components was 1% and 6% at these temperatures, and carbon dioxide accounted for over 70% of the total non-condensable gases. The release of organic compounds at 250°C from peat was nearly four-fold and fifty-fold compared with that of bark and lignite, respectively. The organic materials released from peat were mainly aliphatic mono- and dicarboxylic acids (C 1−C 28), methanol, aliphatic aldehydes, anhydroglucoses and furanoic compounds.