Biodiesel is a liquid fuel whose color varies between golden and dark brown depending on the production feedstock. It is practically immiscible with water, has a high boiling point and low vapor pressure. It is rather non-flammable, less toxic than table salt and biodegrades as fast as sugar. In order to ensure high-quality performance, strict specifications have been established regarding the characteristics of fuel-grade biodiesel. As Green Power Corporation is committed to provide its customers premium quality, our biodiesel already meets the international standards for biodiesel EN 14214 and ASTM D 6751-03 and is certified by PTT as well as the Chulalongkorn University. Generally, biodiesel has physical properties very similar to conventional petroleum diesel, of which the following characteristics are the most distinctive:

The benchmark for measuring the ignition per-formance of diesel fuels is the fuel’s cetane number or cetane index. The higher the cetane index, the faster the fuel ignites, and the smoother the engine runs. U.S. petroleum diesel typically has a cetane index in the low 40s, European diesel typically in the low 50s. The main components of biodiesel are similar to cetane, and thus it naturally possesses a cetane index of 56 to 58. With that biodiesel is a high-quality fuel with excellent ignition performance, even without additives.

The lubricating properties are another important measure of diesel fuel as fuel injectors and some types of fuel pumps rely on fuel for lubrication. The problem with petroleum diesel is that it loses its lubricating qualities with lower sulfur contents, which in turn makes the blending of synthetic additives necessary. Biodiesel in contrast has particularly high lubricating qualities, even though it contains practically no sulfur at all. Lubrication tests revealed that the addition of 1-2% biodiesel to low-sulfur petroleum diesel improves lubricity substantially, thereby reducing wear and tear on engines and injection pumps of around 60%. Biodiesel is thus an environmentally friendly additive to petroleum diesel fuels.

At low temperatures, diesel fuel forms wax crystals, which can clog fuel lines and filters in a vehicle’s fuel system. First it appears cloudy and at even lower temperatures, it becomes a gel that cannot be pumped anymore, resulting in a possible engine failure. The temperature at which paraffin (petroleum diesel) or ester crystals (biodiesel) crystallize before injection, is measured by the cold filter plugging point (CFPP). For rape seed oil the CFPP lies between –12° and –14° Celsius, for yellow grease between –2° and +2° Celsius and for palm oil between +20° and +24° Celsius. In general the CFPP for biodiesel is higher than for petroleum diesel, which makes its performance in cold weather conditions markedly worse. In areas such as Thailand this is of course not a major concern as it would be for example during the winter time in much of the United States. If cold weather conditions do occur, additives manufactured from certain raw materials are available for biodiesel.

The performance of diesel fuels is also measured in terms of fuel economy, which as volumetric efficiency is usually expressed as kilometers traveled per liter of fuel. The energy content per liter of biodiesel is approximately 11% lower than that of petroleum diesel. Vehicles running on B20 are therefore expected to achieve 2.2% fewer kilometers per liter of fuel (20% x 11%). Though insignificant, biodiesel thus tends to reduce fuel economy.