What is Biodiesel?
Biodiesel is a diesel-like biodegradable fuel. It is a non-toxic fuel produced from organic material. The organic raw material needed for producing bio-diesel use fatty substances. They include vegetable oils, waste cooking oil, animal fat and non-edible plant oils.
The properties of bio-diesel resemble closely to petroleum-based diesel. Besides, existing diesel engines do not require major modifications in order to run on bio-diesel. Thus, scientists all over the world are considering it as a substitute for the regular diesel.
Nomenclature of biodiesel blends:
Like the ethanol blends, there is a specific method to denote bio-diesel blends. Consider the following example.
Blend: B10, where B stands for Bio-diesel. The number 10 denotes the percentage of biodiesel in blend by volume. Thus, in simple terms, B10 means 10% biodiesel and 90% regular diesel. Similarly, B50 means 50% biodiesel + 50% regular diesel. However, B100 means 100% bio-diesel.
There are several techniques available for converting the organic material into bio-diesel. They are microemulsion, pyrolysis or thermal cracking and transesterification. Among these, transesterification has achieved commercial success worldwide.
Transesterification is a reaction between the raw material and a suitable alcohol that takes place in presence of a catalyst. Generally, industries prefer using methanol or methyl alcohol. However, other alcohols are also effective. Transesterification converts large triglyceride molecules present in the oil into straight chain molecules. Thus, technically, bio-diesel is a 'mono-alkyl ester'.
Advantages of biodiesel:
- The bio-diesel has higher cetane number compared to petroleum diesel. Hence, it helps in reducing the ignition delay during the combustion process.
- Higher cetane rating also ensures better combustion.
- Reduces emission of CO, CO2 and unburnt hydrocarbon.
- It has better lubricity. Thus, it reduces wear and tear of the engine parts.
Disadvantages of biodiesel:
- The energy content of bio-diesel is less (almost 9% lower) compared to diesel. Hence, it slightly lowers the fuel economy or average of vehicles.
- NOX emissions of the engine increase while running on bio-diesel.
- Use of bio-diesel may cause cold starting problems for engines.
- Using homemade bio-diesel can cause serious damage to engine.
Biodiesel in India:
According to the Indian government, fuel blend B20 will be regularly used throughout the country by the year 2017. However, some reports suggest that the target is difficult to meet. At present, only B5 is available at some outlets.
Here is a list of some of the bio-diesel manufacturers in India:
Read more: What is E-Diesel and How is it made?>>