Influence of Reactor Design on Product Distributions from Biomass Pyrolysis

This paper explores the elements of experimental design that affect outcomes of pyrolysis experiments. Primary pyrolysis products are highly reactive, and reactor properties that tend to promote or suppress their secondary reactions play a key role in determining final product distributions. In assessing particular experimental designs, it is often useful to compare results from different configurations under similar experimental conditions. In the case of pure cellulose, char yields from pyrolysis experiments were observed to vary between 1 and 26%, as a function of changes in reactor design and associated operating parameters. Most other examples have been selected from the pyrolysis of ligno-cellulosic biomass and its main constituents, although relevant data from coal pyrolysis experiments have also been examined. The work focuses on identifying the ranges of conditions where diverse types of reactors provide more dependable data. The greater reliability of fluidized-bed reactors for weight loss (total volatile) determinations in the 300-550 degrees C range, particularly relevant to the study of biomass pyrolysis, has been highlighted and compared with challenges encountered in using wire-mesh reactors and thermogravimetric balances in this temperature range.