Low temperature deoxidization of biomass and its release characteristics of gas products.

Highlights • A broader temperature deoxidization pretreatment during 200–390 °C was conducted. • The release characteristics and kinetic of oxygenated gas products were analyzed. • Different kinds of biomass had different optimum deoxidization temperature. Abstract With a first attempt of extension for torrefaction temperature aiming to reducing more oxygen, low temperature deoxidization of cellulose, hemicellulose, lignin, corn stalk and cotton stalk were performed at various temperatures (200, 230, 260, 290, 320, 350 and 390 °C) respectively. The deoxidization properties of both solid and gas products were investigated. As could be inferred from the results obtained that the main deoxygenation temperature range of cellulose, xylan, corn stalk and cotton stalk were 290–320 °C, 230–260 °C, 260–390 °C and 260–350 °C respectively. The deoxidation effect of lignin was not obvious during 200–390 °C, only 14.80% oxygen was removed at 390 °C. At lower temperature (200–320 °C), the oxygenated gas products dominated by CO 2 and H 2 O were mainly from hemicellulose. In the high temperature range (350–390 °C), cellulose deoxidation was mastery reaction and CO 2 was the main product. The release kinetic analysis of CO 2 and CO during 200–390 °C had been performed for the first time, and as could be inferred from the results obtained that the activation energies for CO 2 and CO release of cellulose, lignin, cotton stalk, corn stalk during low temperature deoxidization were 61.32, 38.41, 43.38, 38.62 kJ/mol and 120.62, 60.55, 83.24, 72.27 kJ/mol, respectively. The release activation energies of hemicellulose in the temperature ranges of 200–290 °C and 320–390 °C were 63.32 and 10.21 kJ/mol for CO 2 and 115.75 and 20.65 kJ/mol for CO respectively. [ABSTRACT FROM AUTHOR]