Switching the production of oxygenated platform chemicals during pyrolysis of sugarcane bagasse by regulating the secondary reactions

Abstract

The secondary reactions during biomass pyrolysis inhibit the selective conversion of biomass into value-added oxygenated platform chemicals. Herein, regulating the secondary reactions during pyrolysis of sugarcane bagasse was systemically explored by adjusting the pyrolysis temperature and H2SO4 loading. It is found that reducing the pyrolysis temperature of sugarcane bagasse from 500 to 300 °C suppresses both primary and secondary reactions. Further adjusting H2SO4 loading can promote primary depolymerization reactions and secondary dehydration reactions during pyrolysis of sugarcane bagasse at 300 °C. When H2SO4 loading is less than 0.5 %, the depolymerization of hemicellulose to form xylosan dominates. The highest yield of xylosan (30.3 %) is obtained by the pyrolysis of 0.5 % H2SO4-loaded sugarcane bagasse at 300 °C. When H2SO4 loading further increases from 0.5 to 1.0 %, the depolymerization of cellulose to levoglucosan becomes the major reaction. The highest yield of levoglucosan (34.2 %) is produced by pyrolysis of 1.0 % H2SO4-loaded sugarcane bagasse at 300 °C. When H2SO4 loading is greater than 1.0 %, the secondary dehydration reactions of cellulose and hemicellulose to respective levoglucosenone and furfural are dominant. These findings demonstrate that adjusting H2SO4 loading is capable of regulating primary and secondary reactions during biomass pyrolysis at low temperatures, thus enabling product switching.