Biodiesel Parameters

To meet the EN 14214 standard the Biodiesel produced must meet the specific parameters. These elaborate parameters will be furnished on special request separately.

Biodiesel refers to a diesel-equivalent processed fuel consisting of short chain alkyl ( methyl or ethyl) esters, made by Transesterification of vegetable oils or animal fats, which can be used (alone, or blended with conventional diesel fuel) in unmodified diesel-engine vehicles.

Biodiesel is distinguished from the straight vegetable oils (SVO) or waste vegetable oils (WVO) used (alone, or blended) as fuels in some diesel vehicles.

The patent for a 'Procedure for the transformation of vegetable oils for their uses as fuels' described the alcoholysis (often referred to as Transesterification) of vegetable oils using ethanol (and mentions methanol) in order to separate the fatty acids from the glycerol by replacing the glycerol with short linear alcohols. This appears to be the first account of the production of what is known as 'Biodiesel' today.

Biodiesel is biodegradable and non- toxic, and typically produces about 60% less net-lifecycle carbon dioxide emissions, as it is itself produced from atmospheric carbon dioxide via photosynthesis in plants. However, the smog forming hydrocarbon emissions are 35% greater, and the Nitrogen Oxide emissions are also greater than those from petroleum-based diesel,.

Description

Biodiesel is a liquid which varies in color — 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. Typical methyl ester Biodiesel has a flash point of ~ 150 °C (300 °F). Biodiesel has a density of ~ 0.88 g/cm³, less than that of water. Biodiesel uncontaminated with starting material can be regarded as non-toxic.

Biodiesel has a viscosity similar to petrodiesel, the current industry term for diesel produced from petroleum. It can be used as an additive in formulations of diesel to increase the lubricity of pure Ultra-Low Sulfur Diesel (ULSD) fuel, which is advantageous because it has virtually no sulfur content. Much of the world uses a system known as the "B" factor to state the amount of Biodiesel in any fuel mix, in contrast to the "BA" or "E" system used for ethanol mixes. For example, fuel containing 20% Biodiesel is labeled B20. Pure Biodiesel is referred to as B100.

Biodiesel is a renewable fuel that can be manufactured from algae, vegetable oils, animal fats or recycled restaurant greases; it can be produced locally in most countries. It is safe, biodegradable and reduces air pollutants, such as particulates, carbon monoxide and hydrocarbons. Blends of 20 percent Biodiesel with 80 percent petroleum diesel (B20) can generally be used in unmodified diesel engines. Biodiesel can also be used in its pure form (B100), but may require certain engine modifications to avoid maintenance and performance problems.

The volumetric energy density of Biodiesel is about 33 MJ/l. This is 9 % lower than regular Number 2 petrodiesel. Variations in Biodiesel energy density is more dependent on the feedstock used than the production process. Still these variations are less than for petrodiesel. It has been claimed Biodiesel gives better lubricity and more complete combustion thus increasing the engine energy output and partially compensating for the higher energy density of petrodiesel.

Technical standards

The common international standard for Biodiesel is EN 14214.

There are additional national specifications. ASTM D 6751 is the most common standard referenced in the United States and Canada. In Germany, the requirements for Biodiesel are fixed in the DIN EN 14214 standard and in the UK the requirements for Biodiesel is fixed in the BS EN 14214 standard, although these last two standards are essentially the same as EN 14214 and are just prefixed with the respective national standards institution codes.

There are standards for three different varieties of Biodiesel, which are made of different oils:

RME ( rapeseed methyl ester, according to DIN E 51606)
PME (vegetable methyl ester, purely vegetable products, according to DIN E 51606)
FME (fat methyl ester, vegetable and animal products, according to DIN V 51606)

The standards ensure that the following important factors in the fuel production process are satisfied:

Complete reaction.
Removal of glycerin.
Removal of catalyst.
Removal of alcohol.
Absence of free fatty acids.
Low sulfur content.

Contamination by water

Biodiesel may contain small but problematic quantities of water. Although it is hydrophobic (non-miscible with water molecules), it is said to be, at the same time, hygroscopic to the point of attracting water molecules from atmospheric moisture; in addition, there may be water that is residual to processing or resulting from storage tank condensation. The presence of water is a problem because:

Water reduces the heat of combustion of the bulk fuel. This means more smoke, harder starting, less power.
Water causes corrosion of vital fuel system components: fuel pumps, injector pumps, fuel lines, etc.
Water & microbes cause the paper element filters in the system to fail ( rot), which in turn results in
   premature failure of the fuel pump due to ingestion of large particles.
 Water freezes to form ice crystals near 0 °C (32 °F). These crystals provide sites for nucleation and
   accelerate the gelling of the residual fuel.
 Water accelerates the growth of microbe colonies, which can plug up a fuel system. Biodiesel users who have    heated fuel tanks therefore face a year-round microbe problem.

Production

Chemically, transesterified Biodiesel comprises a mix of mono- alkyl esters of long chain fatty acids. The most common form uses methanol to produce methyl esters as it is the cheapest alcohol available, though ethanol can be used to produce an ethyl ester Biodiesel and higher alcohols such as isopropanol and butanol have also been used. Using alcohols of higher molecular weights improves the cold flow properties of the resulting ester, at the cost of a less efficient Transesterification reaction. A lipid Transesterification production process is used to convert the base oil to the desired esters. Any Free fatty acids (FFAs) in the base oil are either converted to soap and removed from the process, or they are esterified (yielding more Biodiesel) using an acidic catalyst. After this processing, unlike straight vegetable oil, Biodiesel has combustion properties very similar to those of petroleum diesel, and can replace it in most current uses.

A byproduct of the Transesterification process is the production of glycerol. For every 1 tonne of Biodiesel that is manufactured, 100 kg of glycerol are produced. Originally, there was a valuable market for the glycerol, which assisted the economics of the process as a whole. However, with the increase in global Biodiesel production, the market price for this crude glycerol (containing 20% water and catalyst residues) has crashed. Research is being conducted globally to use this glycerol as a chemical building block.

Usually this crude glycerol has to be purified, typically by performing vacuum distillation. This is rather energy intensive. The refined glycerol (98%+ purity) can then be utilised directly, or converted into other products.

A variety of oils can be used to produce Biodiesel. These include:

Virgin oil feedstock; rapeseed and soybean oils are most commonly used, soybean oil alone accounting for    about ninety percent of all fuel stocks; It also can be obtained from field pennycress and Jatropha other crops    such as mustard, flax, sunflower, canola, palm oil, hemp, and even algae
Waste vegetable oil (WVO);
Animal fats including tallow, lard, yellow grease, chicken fat, and the by-products of the production of
   Omega-3 fatty acids from fish oil.
Sewage. A company in elsehwhere in the world has successfully developed a system for using sewage waste as a substrate for algae and then producing bio-diesel.

The highest yield feedstock for Biodiesel is algae, which can produce 250 times the amount of oil per acre as soybeans.

Algae grows where and when people don't want it. It is part of nature's system of reprocessing chemicals in water and air, powered by sunlight. Algae grows very quickly and, like all plants, it eats CO 2.