A study of cellulose pyrolysis chemistry and global kinetics at high heating rates

Cellulose pyrolysis has been studied in a laminar entrained flow reactor (L EFR). As described in the previous companion paper, the reactor is capable of high heating rates (similar to 10(4) K/s) and has been characterized in detail to ensure that pyrolysis of lignocellulosic materials occurs under k inetic control at the conditions of the reactor. The extent of cellulose py rolysis in the LEFR was monitored by sampling the gas phase products with a molecular beam mass spectrometer system, and independently by sampling and weighing residues on a filter paper. Varying the reactor furnace temperatu re controls the pyrolysis severity. Quantitative cellulose pyrolysis data h ave been compared to several published reaction rates. Published models tha t involve low activation energy rates from other high temperature experimen ts described in the literature best approximate the results obtained in thi s study. Factor analysis of the mass spectral data requires two principal c omponents to interpret the gas phase product composition. This suggests tha t the primary cellulose pyrolysis products were involved in subsequent seco ndary reactions that directly compete with the primary release of products at the conditions in this reactor. A rate is presented that describes the o bserved thermal destruction of primary pyrolysis products.