biofuels

FAME

fatty acid methyl ester

problems with raw biomass combustion

• Local pollutants such as nitrogen oxides and PM

• PM decreases when wood is dry - combustion is more effective when wood is dry - no energy is going into water molecules

transesterification to produce biodiesel

vegetable oils are triglycerides and glycerol is produced as a side produce in this procedure

bioethanol production

• from biomass

• fermentation of starch

starch and cellulose

a glucose polymer linked with alpha 1-4 linkages, cellulose is a glucose polymer linked with beta 1-4 linkages

starch is soluble and easily hydrolysed, cellulose is not (chemically resistant)

biorefining for fuel: proposed benefits

• Carbon neutral

• Renewable

• New agricultural industries

problems with biodiesel

• Use of a food supply for fuel (vegetable oils)

• Use of arable land for fuel

• Production of alkaline wastes

• Emulsification following catalyst reaction with FFA

• Only a tiny fraction of biomass utilised

• Increased synthetic fertiliser use -> not carbon neutral combustion

• Increased synthetic fertiliser use -> N2O means increased GHG emissions, not carbon neutral

what do 2nd generation bio-fuels rely on

non-food based biomass

emulsification

Glycerol/water/alkaline catalysts/free fatty acids/FAMEs.

Some water soluble, some not, some potential surfactants (soap)

uses of glycerol/glycerin

• medical

• solvent

• cosmetics

• dynamite

• automotive

• food industry

plant waste

Think about plant waste where starch is the feedstock. Or worse, where glucose is the feedstock.