Preparation and formation mechanism of levoglucosan from starch using a tubular furnace pyrolysis reactor

Tubular furnace pyrolysis reactor for the production of organic liquids from biomass has been demonstrated at a pilot-scale of 500 g/batch of dry feed at a temperature of 360–420 °C. Treatment of starch gives high yields of 1,6-anhydro-β-d-glucopyranose (levoglucosan, LG). The yield depends on the heater temperature and the vacuum pressure in the reactor. The maximum yield of levoglucosan from corn starch is about 56% (analytical value) at ultimate pressure of 6 × 10−2 Pa, pumping speed of 15 L/s and temperature of 390 °C. Under the same conditions, the products of levoglucosan pyrolysis are exactly the same as starch pyrolysis. Based on these experimental results and further thermal analysis, a new pyrolysis mechanism is provided and discussed.