Rapid-cooling, continuous-feed pyrolyzer for biomass processing. Preparation of levoglucosan from cellulose and starch

Novel design of pyrolyzer was developed for efficient collection of primary degradation products from biomass. The apparatus consists of a pair of horizontal belt conveyers facing to each other, in a reduced-pressure chamber with pressures ranging from 600 Pa to 8 kPa. The lower belt feeds the powder of raw material to the pyrolysis region heated up to 450 degrees C; the upper belt facing the heated part is cooled from the top to condense the evaporated products with minimal secondary degradation. A continuous-feed pyrolyzer for the production of organic liquids from cellulosic biomass has been demonstrated at a laboratory-scale of 5-10 g/h of dry feed in temperature of 410-450 degrees C. Treatment of cellulose and starch gave high yields of 1,6-anhydro-P-D-glucopyranoside (levoglucosan). The yield depended on the heater temperature and the residual air pressure in the chamber. The maximum yield of levoglucosan from microcrystalline cellulose (Avicel) was approx. 70% (analytical value) under residual air of 5 kPa. (c) 2006 Elsevier B.V. All rights reserved.