Pyrolysis of cellulose using a single pulse shock tube

The decomposition of cellulose in pure argon, hydrogen/argon, and methane/argon mixture was studied at temperature of 1000-2500 K and reaction time of 0.3-3.0 ms using a single pulse shock tube. The influences of temperature, gasification atmospheres, and reaction time on the yields of gaseous products were investigated. The primary pyrolysis products in all reaction atmospheres investigated are carbon monoxide, carbon dioxide, methane, ethylene, and acetylene.;Pyrolysis in hydrogen/argon mixture as compared to pyrolysis in pure argon caused a significant decrease in carbon monoxide and carbon dioxide. Increasing the hydrogen content of the mixture from 1% to 5% did not change the carbon monoxide yield; however, it caused much larger decrease in the carbon dioxide yield. A slight increase in the ethylene yield and a slight decrease in the acetylene yield were observed in the cellulose pyrolysis in hydrogen/argon mixture. The increase in ethylene and decrease in acetylene was larger in 5% hydrogen than in 1% hydrogen. Pyrolysis with hydrogen/argon mixture resulted in a drastic increase in the yield of methane. The methane yield greatly increased with increasing hydrogen content of the reaction atmosphere.;Pyrolysis with methane (1% methane in argon) as compared to the pyrolysis of cellulose in pure argon resulted in significant changes in the product yields. The yields of carbon oxides and acetylene were significantly decreased. Only the ethylene yield was enhanced by methane atmosphere.;The product yields and distributions were greatly influenced by varying the reaction time. The temperature for the onset of cellulose decomposition and the evolution of the pyrolysis products was increased by shorter reaction time. The maximum yields usually increased with shorter reaction time. The temperature at which the maximum yields occurred (especially for methane, ethylene, and acetylene) was also increased by shorter reaction time.;The results of this study strongly support the conclusion of previous fast pyrolysis studies that biomass can be completely converted to valuable gases under conditions of high temperature, high heating rate, short reaction time, and rapid cooling.