Analytical Pyrolysis of Plant Materials

Wood is found mainly in trees and shrubs, although woody tissues are also found in some herbaceous plants. Wood is a complex material and living tree trunks are composed of a variety of tissues (pith, xylem, cambium, phloem, and bark). The wood from most angiosperm trees is known as hardwood, while the wood from gymnosperms is known as softwood. 

There are numerous industrial applications of wood pyrolysis with the goal of generation of charcoal, methanol, or acetic acid for practical use. Analytical pyrolysis studies are only a small part of the subject of wood pyrolysis. These pyrolysis studies are performed with a variety of purposes, some for assisting the industrial uses of wood pyrolysis [1]. 

The main components of wood are cellulose, hemicelluloses, lignin, proteins, and small molecules including several inorganic compounds. The pyrolysis products of each individuai type of macromolecular component of wood were described in Part 2 of this book. Some differences are seen in the pyrolysis of pure macromolecular components as compared to the pyrolysis results of the same component from the wood matrix. This is seen mainly for cellulose and hemicelluloses. However, the pyrolysis components are well recognizable, and it is common to use wood pyrolysates to trace a certain group of compounds to celiulose, hemicellulose, lignin, small molecules existent in wood, etc. 

The main applications for analytical pyrolysis studies can be listed as follows  

A special subject related to wood pyrolysis is the study of the composition of wood smoke. Smoke composition studies are important in relation to health issues and particularly to smoking of certain types of food for preservation and for achieving special taste. Smoke is generated both from polymers and from small molecules existent in wood. The main components found in curing smoke are probably phenols. Some of these are indicated below  

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