Torrefaction: "Wood is the new coal"






Today I'll be talking about the benefits of torrefaction (brief video here).

Torrefaction of biomass as well as waste material such as old tyres and food waste tackles two major issues: waste management in both developing and developed nations, and carbon dioxide emission reduction. How? Good question.

Ever since countries like Denmark, Sweden, and others rich in forestry residue successfully implemented co-firing (that is, the generation of heat and/or electricity for citizens by the combustion of coal and biomass), other nations such as the UK have well embraced this technology. A major problem however, is that biomass is not that good. Its energy density is considerably lower than that of coal, and it possesses a high moisture content, is difficult to transport, among other problems. So when the torrefaction idea came along, it seemed like a well nice intervention at the right time. Want to find out more? Head on here for a start, then!

By the way, I was a bit confused about the difference between energy density (volume basis) and energy density (mass basis)-- terms used by torrefaction experts a lot. Here's some clarification:

"Energy Density is the amount of energy stored in a given system or region of space per unit volume or per unit mass. The use of volume or mass to describe energy density is dependant upon the context in which the energy density of an element or compound is described. For example, in most cases, the energy density of a liquid is best described in terms of mass. In the case of a gas, using a per unit volume description may be more appropriate because a gas, even when compressed, occupies an overwhelming volume as compared to a liquid. Therefore the energy density of a gas by mass appears quite substantial, but when one looks to the volume of gas required to achieve the desired energy density, it can become impractical."

More information can be found here.

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