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

Abstract 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 °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 °C. Treatment of cellulose and starch gave high yields of 1,6-anhydro-β- 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.