Pyrolysis oil are affected by temperature, reaction time, algae species, algae concentration, reaction atmosphere, and catalysts, in subcritical water reaction conditions. 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. Tar can be produced from coal, wood, petroleum, or peat. Wood-tar creosote is a colourless to yellowish greasy liquid with a smoky odor, produces a sooty flame when burned, and has a burned taste. It is
Coal oil Coal oil Coal oil is a shale oil obtained from the destructive distillation of cannel coal, mineral wax, or bituminous shale, once used widely for illumination. Chemically similar to the more refined, petroleum-derived kerosene, it consists mainly of several hydrocarbons of the alkane series, with 10 to 16 carbon atoms in each molecule and a higher boiling point (175–325 °C) than gasoline or the petroleum ethers and lower than the oils. Because kerosene was first derived from cannel coal, classified as terrestrial type of oil shale, it continued to be popularly referred to as "coal oil" even after production shifted