Glossary of Terms
Biomass is all biological material derived from either living or recently dead plant or animal organisms. In the context of energy production, biomass is classed as a renewable resource and usually refers to plant material.
Torrefaction is the process of heating biomass in the absence of oxygen, similar to the way that coffee is roasted. This removes chemically bound oxygen and gives a fuel with higher energy content and improved combustion properties.
Hemicellulose is a natural polymer found in biomass along with cellulose and lignin and is the compound most readily degraded by torrefaction.
Pyrolysis is the process of heating material (in our case biomass) in the absence of oxygen to make char-type products. Mild pyrolysis conditions (200 – 300°C) are used for torrefaction and higher temperatures (400-500°C) used for producing charcoal.
The torrefaction reaction is exothermic, meaning it generates heat. This heat can then be re- used in the process to dry and sustain the reaction without any other external source.
When wood is burned incompletely in a fire (i.e. when it’s wet), tarry smoke or creosote is formed and condenses on the inside of chimney flues.
PM10 and PM2.5
PM10 and PM2.5 are measurements of fine particulate matter (dust) that are present in the air we breathe. Around 10% of the total particulates in the air are made from human activity and these can have a severe effect on health. Wood smoke and smoky coal burning contributes to large amounts of particulates emitted to the atmosphere.