Abstract
Stability of fast pyrolysis bio-oils is a complex
phenomenon, especially as numerous compounds with
different reactivities are involved. Acid-catalysed
condensation and polymerization reactions of carbonyl
compounds and reactive lignin-derived radical species
take place which increase the share of water-insoluble
compounds, average molecular weight and viscosity of
bio-oil. Aging can be slowed by dilution, removing of
alkali metals catalysing the aging reactions, removing
hemicelluloses causing acidic environment, or adding
antioxidants to stabilize reactive specimens. In some
cases, controlled aging can be used to stabilize bio-oil.
Enhanced stabilization can be achieved by esterification
and acetalization of carboxylic acids and carbonyls,
respectively. Stage-fractionation of bio-oil and separate
stabilization of these fractions is one alternative
approach. In low temperature catalytic hydrodeoxygenation
reactive carbonyl compounds are stabilized by hydrogen.
All these stabilization methods have advantages and
disadvantages. The appropriate stabilization method will
depend on the bio-oil application. When hydrocarbon fuels
are the desired product, more expensive hydrotreatment
(HDO) routes to stabilization might be justified. When
targeted as feedstock for an oil refinery, thermal
stability is a key factor. Viscosity increase would be an
indicative factor on polymerization tendency of the oil
but also oxygen content, distillability, and micro carbon
residue.
| Original language | English |
|---|---|
| Title of host publication | Fast Pyrolysis of Biomass |
| Subtitle of host publication | Advances in Science and Technology |
| Publisher | Royal Society of Chemistry RSC |
| Chapter | 8 |
| Pages | 138-159 |
| ISBN (Print) | 978-1-78262-618-3, 978-1-78801-024-5, 978-1-78801-186-0 |
| DOIs | |
| Publication status | Published - 2017 |
| MoE publication type | D2 Article in professional manuals or guides or professional information systems or text book material |