Power generation from biomass

Pure Plant Oil (PPO)

Pure Plant Oil, also known as or Pure Vegetable Oil (PVO) or Straight Vegetable Oil (SVO), either raw or refined, is mainly composed by vegetable glycerides. It is obtained from edible or non-edible fruits or seeds of various and very different oleaginous crops, such as palm, cotton, sunflower, jatropha, karanja, soybean, rapeseed, brassica, copra, groundnut, and many others.
It can be produced by mechanical (pressing) and chemical (solvent) extraction, in case followed by chemical and/or physical refining to improve oil quality. Decentralised small scale extraction is usually carried out through mechanical pressing and filtering only, while industrial extraction is normally performed by mechanical pressing followed by chemical extraction and refining of the oil.
The possibility to run tractors, turbines and small engines make PPO an attractive alternative diesel fuel in rural areas.

Compared to fossil diesel, typically PPOs has higher viscosity (approximately one order of magnitude), density (up to +10%), lower Cetane number (33-38 versus >45) and calorific value (36-38 versus 42-43 MJ/kg). The cloud point as well tends to be higher, up to +30°C when compared to light diesel. Contaminants, as phosphorous and others, are present in unrefined PPO. Oxidation stability and iodine number, acidity and carbon residue are also important issue as regards PPO quality.

These properties of PPOs, expecially the high viscosity, considerably affect the characteristics of the fuel spray in the combustion chamber, such as spray penetration, spray angle and droplets size and distribution, while contaminants generate long-term problems on injectors, storage, etc.
PPO can successfully be used in converted systems, normally engines. However, further knowledge has to be gained in this field in order to overcame the technical limitations of long term use of PPO, i.e. engine chocking for ICs, cease of fuel injection, gum formation and piston sticking, or to develop new applications, as micro gas turbines.
During the project, part of the work will be devoted to extend the knowledge on the use of pure plant oil and plant oil-diesel mixture in both IC engines (diesel cycle) and Micro Gas Turbines (MGT) in order to overcome the technical limitations arised and find innovative solutions to simplify its introduction in a short chain market.
Test will be carried out both at CREAR and NAMI/ZIL facilities, on adapted MGT and Diesel engines.