Pyrolysis oil, sometimes also known as biocrude or bio-oil, is a synthetic fuel with few industrial application and under investigation as substitute for petroleum.
It is obtained by heating dried biomass without oxygen in a reactor at a temperature of about 500 °C (900 °F) with subsequent cooling, separation from the aqueous phase and other processes.
Pyrolysis oil is a kind of tar and normally contains levels of oxygen too high to be considered a pure hydrocarbon.
This high oxygen content results in non-volatility, corrosiveness, partial miscibility with fossil fuels, thermal instability, and a tendency to polymerize when exposed to air.
[3] Pyrolysis is a well established technique for decomposition of organic material at elevated temperatures in the absence of oxygen into oil and other constituents.
The solid residue, charcoal, is mainly carbon (about 70%), with the remainder being tar-like substances which can be driven off or decomposed completely only by raising the temperature to above about 600 °C to produce Biochar, a high-carbon, fine-grained residue that today is produced through modern pyrolysis processes, which is the direct thermal decomposition of biomass in the absence of oxygen, which prevents combustion, to obtain an array of solid (biochar), liquid—Pyrolysis oil (bio-oil/pyrolysis-oil), and gas (syngas) products.
Miao et al. (2004b) performed fast pyrolysis of Chllorella protothecoides and Microcystis areuginosa at 500 °C, and bio-oil yields of 18% and 24% were obtained, respectively.
When Chlorella protothecoides was cultivated heterotrophically, bio-oil yield increased to 57.9% with a heating value of 41 MJ/kg (Miao et al., 2004a).
residue with and without the presence of HZSM-5 catalyst and obtained bio-oil rich in aromatic hydrocarbons from catalytic pyrolysis.
These properties are similar to those of Illinois shale oil (Jena et al., 2011a; Vardon et al., 2012), which may indicate that pyrolytic bio-oil is suited for replacing petroleum.
[8]Hydrothermal liquefaction (HTL) is a thermal depolymerization process used to convert wet biomass into an oil[9]—sometimes referred to as bio-oil or biocrude—under a moderate temperature and high pressure[10] of 350 °C (662 °F) and 3,000 pounds per square inch (21,000 kPa).
The crude-like oil (or bio-oil) has high energy density with a lower heating value of 33.8-36.9 MJ/kg and 5-20 wt% oxygen and renewable chemicals.
Typical pyrolysis processes require a water content of less than 40% to suitably convert the biomass to bio-oil.
[citation needed] Bio-oil typically requires significant additional treatment to render it suitable as a refinery feedstock to replace crude oil derived from petroleum, coal-oil, or coal-tar.
Tar is a black mixture of hydrocarbons and free carbon obtained from a wide variety of organic materials through destructive distillation.