|
| You are now viewing: |
Module 6: |
> |
Unit 1 > Lesson 1 |
|
| |
| Wood Composition |
| The four major components of woody biomass are: cellulose, hemicellulose, lignin, and mineral components. |
Cellulose |
- Cellulose makes up nearly 50 percent of woody plant mass.
- Trees produce cellulose to store carbon, hydrogen, and oxygen.
- Cellulose is made up the starches, proteins, and sugars trees need to grow.
- It is the most abundant organic material on Earth.
- We can transform cellulose into ethanol, cellophane, and cellulose ethers such as acetate, rayon, and nitrates.
|
Due to the relatively high manufacturing cost, many of these derivatives have only specialty applications. The primary source of wood cellulose in the south is softwood species such as pine, but over the last twenty years, hardwood utilization has increased. |
|
Wood Composition
P. Daniel Cassidy
Sarah F. Ashton Univ. of Georgia |
|
Hemicellulose
Hemicellulose is a carbohydrate that comprises 25 to 35 percent of the dry weight of wood residues. It is second only to cellulose in abundance. The use of hemicellulose is currently limited due to manufacturing related costs.
Lignin Lignin is a polymer that holds together the cellulose and hemicellulose components of woody biomass. Lignin constitutes about 15 to 25 percent of the weight of woody biomass. Lignin has not yet been used as a raw material for industrial purposes in large quantities. This reflects the chemical complexity of lignin. |
|
|
| Mineral Components |
- Woody biomass is composed of many mineral elements including carbon, oxygen, and hydrogen.
- While these elements do produce energy during combustion, they do affect the energy content of woody biomass.
- On average, hardwoods have a higher concentration of mineral elements than softwoods.
- The presence of minerals is more affected by the site where trees are grown rather than tree age, species, or size.&
|
Other elements included nitrogen, sulfur, chlorine, and heavy metals. All can have negative impacts, potentially, when combustion is the technological conversion process being employed.
|
|
|
|
|
|
|
|
|
