Neste Oil has started production at its biodiesel plant in Singapore, the world’s largest with an annual capacity of 800,000 tons. The plant will produce the NExBTL diesel which, according to the company reduces the carbon emissions by 40 to 80 percent depending on the percentage blending with the conventional diesel.
The biodiesel from the plant can be either blended with the conventional diesel or used directly. The company claims that the biodiesel is compatible with the all the diesel engines currently in use. Neste Oil is building a similar plant in Rotterdam, The Netherlands which should be ready by Q2 2011.
The plant uses either vegetable oil or a mixture of oils and residual animal fats from the food industry. The plant uses a new production technique, the NExBTL technology, which is slightly different from the usual production technique of biodiesel.
The basic principle used in producing biodiesel is esterification (or transesterification). In commercial production of biodiesel, fatty acids (found in plant-derived oils, animals fats and greases) are made to react with an alcohol (usually methanol) with potassium hydroxide (or other hydroxide) as catalyst.
It is clear that a greater concentration of fatty acids in any raw material would increase the output of biodiesel. Plant-derived oils like rapeseed oil are rich in fatty acids and can be directly used for producing biodiesel through transesterification. The animal fats, however, have lower fatty acid content and thus they are first treated with alcohol to generate an ester and then the resulting ester is treated with another ester in a replacement reaction to get biodiesel.
The process is thus very simple and generates useful by-products such are glycerol which has wide applications in several industries like soap manufacturing.
The NExBTL technology, on the other hand, does not involve any esterification/transesterification processes. Instead, the process involves hydrogenation of the plant or animal oil. Hydrogenation under the influence of catalyst removes oxygen from the fatty acids and reduces them into alkanes which closely resemble conventional diesel oil.
It is important, though, that raw materials produced should be sustainable. Unchecked exploitation of plants and plant products, which may be used as food in some part of the world, for biofuel production could not only lead to environmental disasters but social and economic problems as well. Biodiesel production from algae has also been proposed and research work on the same is underway in many parts of the world. However, the ability to provide a net reduction in carbon emissions is in doubt.
Image: rrelam at Flickr/CC
The views presented in the above article are author’s personal views and do not represent those of TERI/TERI University where the author is currently pursuing a Master’s degree.
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