Fluidised bed pyrolysis of lignocellulosic biomasses and comparison of bio-oil and micropyrolyser pyrolysate by GC/MS-FID

Abstract

The fast pyrolysis of spruce (Picea abies), short rotation willow coppice (Salix alba), Miscanthus (Miscanthus x giganteus), and wheat straw (Triticum aestivum) was compared on a laboratory scale bubbling fluidized bed reactor at 460–475°C. The presence of ash, ranging from 0.26wt.% for spruce to 3.76wt.% for wheat straw (moisture free basis) favoured decomposition of cell-wall constituents to char (spruce [11.4wt.%]<Salix [16.2wt.%]<Miscanthus [21.8wt.%]<wheat straw [21.5wt.%]) with a reduction of liquid organic product (spruce [53.8wt.%]>Salix [45.4wt.%]>Miscanthus [37.3wt.%]>wheat straw [37.2wt.%]). Bio-oils from Miscanthus and wheat straw were inhomogeneous. Differences between absolute masses of compounds determined by GC/MS-FID of the bio-oils compared with Py-GC/MS-FID suggested a greater role of secondary reactions at the fluidised bed scale, with reduced concentrations of certain lignin-derived, furan and pyran compounds.