Pure plant oil (PPO), a term used mainly in the European Union (straight vegetable oil, SVO, is the more common term in the United States) refers to vegetable oils used to fuel diesel engines . PPO is produced by pressing of oil plants, both edible like rapeseed, soybean, moringa, and the fruits of oil palms, and non-edible like jatropha and karanj. The simplest process is cold pressing which generally results in an engine fuel grade PPO after filtering and removal of sediments. Waste cooking oil can also be converted to PPO.
While some diesel engines can run on SVO without modification, steps must be taken to address problems in colder climates, since it is generally more viscous than petrodiesel and has a higher freezing point.
It can be used in its pure form and in any mixture with diesel/biodiesel. For engines designed to burn diesel fuel, the viscosity of vegetable oil must be lowered to allow for proper atomization of the fuel, otherwise incomplete combustion and carbon build up will ultimately damage the engine.
Fot more info see:
1. BioenergyWiki Article on Pure Plant Oil, http://www.bioenergywiki.net/Pure_plant_oil.
2. Wikipedia Article on Vegetable Oil Fuel, http://en.wikipedia.org/wiki/Vegetable_oil_fuel
