CELLULOSE PYROLYSIS AND QUANTUM-CHEMISTRY

Cellulose is the major constituent of most plants of interest as renew able sources of energy and is the most extensively studied form of bio mass or biomass constituent. Predicting the mass loss and product yiel ds when cellulose is subjected to increased temperature represents a f undamental problem in the thermal release of biomass energy. Unfortuna tely, at this time, there is no internally consistent model of cellulo se pyrolysis that can organize the varied experimental data now availa ble or provide a guide for additional experiments. Here, we present a model of direct cellulose pyrolysis using a multistage decay scheme th at we first presented in the IJQC in 1984. This decay scheme can, with the help of an inverse method of assigning reaction rates, provide a reasonable account of the direct fast pyrolysis yield measurements. Th e model is suggestive of dissociation states of d-glucose (C6H10O5,), the fundamental cellulose monomer. The model raises the question as to whether quantum chemistry could now provide the dissociation energies for the principal breakup modes of glucose into C-1, C-2, C-3, C-4, a nd C-5 compounds. These calculations would help in achieving a more fu ndamental description of volatile generation from cellulose pyrolysis and could serve as a guide for treating hemicellulose and lignin, the other major biomass constituents. Such advances could lead to the deve lopment of a predictive science of biomass pyrolysis that would facili tate the design of liquifiers and gasifiers based upon renewable feeds tocks. (C) 1998 John Wiley & Sons, Inc.