Neste Oil (Neste) is a Finnish oil refining company that focuses on advanced, low-emission transportation fuels.
Neste has the distinction of starting up the world’s largest biodiesel plant, which began production last month in Singapore. The plant has an annual capacity of 800,000 tons and will produce biodiesel fuel using Neste’s NExBTL renewable diesel production technology.
Neste owns more than 30 international patent applications, including at least two directed to biodiesel production technology.
International Publication No. WO 2007/068798 (’798 Publication) is entitled “Process for the manufacture of hydrocarbons” and is directed to processes for manufacturing branched saturated hydrocarbons that include a skeletal isomerisation step followed by a deoxygenation step.
According to the ’798 Publication, the process uses renewable sources, such as plant, vegetable, animal and fish fats and oils and fatty acids and first subjects them to skeletal isomerisation, which means forming branches in the fat molecule’s main carbon chain while maintaining the same number of carbon atoms.
Then the branched hydrocarbons are deoxygenated by either hydrodeoxygenation, which removes the oxygen in the form of water, or carboxylation/decarbonylation, which removes the oxygen in the form of CO or CO2.
According to Neste’s renewable diesel product information page, the NExBTL biodiesel provides better performance than conventional biodiesel due to a high cetane number that allows efficient combustion. Cetane number is a metric for describing the ignition quality of diesel fuel or its components.
The ’798 Publication states:
A high quality hydrocarbon product with good low temperature properties and high cetane number is obtained, employing minimum amount of hydrogen in the process.
According to Neste’s press release, the NExBTL biodiesel enables reductions in greenhouse gas emissions of between 40-80% over the product’s entire life cycle compared to fossil diesel. The exact number depends on the type of feedstock used and the percentage blending with conventional diesel.
A second Neste patent application directed to biodiesel production technology is International Publication No. WO 2008/152199 (’199 Publication). The ’199 Publication, entitled “Process for producing branched hydrocarbons,” is directed to processes for producing saturated hydrocarbons for use as diesel fuels through a condensation step and a combined hydrodefunctionalization and isomerisation step.
The process starts with a biological feedstock and first condenses it, which the ’199 Publication defines as combining two feedstock molecules to form a molecule long enough to serve as a diesel or other fuel.
Next, the condensed product is subjected to a combined hydrodefunctionalization and isomerisation step to remove oxygen, nitrogen and sulphur atoms and isomerize the molecules into branched hydrocarbons.
According to the ’199 Publication:
The obtained diesel fuels, kerosenes and gasolines can be mixed in conventional fuels without any blending limitations and they fulfill the highest technical requirements without extensive use of additives.
Like the hydrocarbons they produce, Neste’s biodiesel plants are branching out across the globe. Before the Singapore plant came on stream, the company was operating two renewable diesel plants in Porvoo, Finland. Neste is also building another facility comparable in scale to the Singapore plant in Rotterdam, which is scheduled to start production in the first half of 2011.