Definition of Bio-crude
– Bio-crude is a liquid biofuel produced by biomass solvent liquefaction: pressurized, liquid phase thermal processing of biomass to form a liquid.
– Like bio-oil, bio-crude put biomass in a form that is more easily pumped; stored; fed to useful processes; and more compatible to chemical modification, processing, or extraction.
– Bio-crude is a complex mixture of oxygenated organic compounds with a wide molecular weight range.
– Bio-crude is more of an equilibrium product, and is often viscous, but thermally stable over time.
– Bio-crude has properties that are dissimilar to petroleum oil or bio-oils, including
- Not readily miscible with petroleum.
- Contains 5 to 10% moisture, but does not readily adsorb more.
- Frequently contains 5 to 15% oxygen, which is more than petroleum but less than bio-oil.
- Slightly higher density than petroleum, but much less than bio-oils.
- Contains more nitrogen and sulfur than typical petroleum, commensurate with the starting biomass.
Production of Synthetic Fuels and Chemicals from Biomass
Prabir Basu, in Biomass Gasification, Pyrolysis and Torrefaction (Second Edition), 2013
Bio-oil is the liquid fraction of the pyrolysis product of biomass. For example, a fast pyrolyzer typically produces 75% bio-oil, 12% char, and 13% gas. Bio-oil is a highly oxygenated, free-flowing, dark-brown (nearly black) organic liquid (Figure 11.1) that contains a large amount of water (~25%) that is partly the original moisture in the biomass and partly the reaction product. The composition of bio-oil depends on the biomass it is made from as well as on the process used.