Scania is joining forces with Neste Oil in Finland for comprehensive testing of Neste’s NExBTL renewable diesel.
Scania will subject NExBTL fuel blends to environmental and operational trials, starting in autumn 2007 and lasting until the end of 2010. The tests will involve the monitoring of exhaust emissions and engine conditions resulting from different mixes of the renewable diesel and standard diesel. The varying fuel mixtures will be tested in distribution vehicles and shuttle vessels in the Stockholm region, as well as city buses in Helsinki.
Six Scania city buses form part of the trial. Four of them will run on 100% NExBTL and two on normal diesel. The project also involves tests with various mixes on some 100 vehicles operated by Posten Logistik, the logistics division of Swedish Post, and 2-3 ships in the Stockholm archipelago operated by Waxholmsbolaget.
Neste Oil’s refinery-based proprietary NExBTL technology is based on the high-pressure hydrogenation of fatty acids. The product is a synthetic diesel fuel, free of oxygen and aromatic compounds. Side products include propane and gasoline. The process can use a flexible input of any vegetable oil or animal fat to produce a product with characteristics similar to Fischer-Tropsch output. (Earlier post.)
The NExBTL process is different than both the transesterification process used to produced fatty acid methyl ester (biodiesel) and Fischer-Tropsch conversion used in BTL projects.
Neste says that when using NExBTL engine efficiency remains high, while NOx emissions are down almost 20% and particulates down close to 30% compared to standard diesel. In addition, the fuel reduces fossil CO2 emissions by up to 80%.
|Fuel Property Comparison|
|Density at +15º C (kg/m3||775 ... 785||770 ... 785||~885||~835|
|Viscosity at +40º C (mm2/s||2.9 ... 3.5||3.2 ... 4.5||~4.5||~3.5|
|Cetane number||~84 ... 99||~73 ... 81||~51||~53|
|Cloud point (ºC)||~ -5 ... -30||~ 0 ... -25||~ -5||~ -5|
|Heating value (lower) (MJ/kg)||~44||~43||~38||~43|
|Heating value (MJ/liter)||~ 34||~ 34||~ 34||~ 36|
|Polyaromatic content (wt %)||0||0||0||0|
|Oxygen content (wt %)||0||0||~ 11||0|
|Sulfur content (mg/kg)||< 10||< 10||< 10||< 10|
Scania’s laboratory tests corroborate that bio-based synthetic diesel has great potential. Simply switching to such fuel from standard diesel can significantly improve emissions. The possibility of mixing it freely with standard diesel makes the fuel interesting for old vehicles and engines as well. We look forward to participating in these trials.—Hasse Johansson, Group Vice President R&D at Scania
Scania notes that its tests of other diesel fuels have proven that the composition of a fuel has a direct bearing on its environmental performance and that there is scope to optimize engines for different fuels.
Neste recently launched its NExBTL plant at the Porvoo refinery in Finland. The new plant will be capable of producing 170,000 t/a of NExBTL diesel fuel from a flexible mix of vegetable oil and animal fat. (Earlier post.)
The company has also just signed a contract with Raisio under which Raisio will supply 10,000 tons of rapeseed oil to Neste Oil this year for use as a feedstock at the NExBTL plant. In September 2006, Neste Oil contracted to buy virtually all the byproduct tallow produced by the Finnish food processing industry as raw material input for its biodiesel production.
Neste is building a second NExBTL plant at Porvoo, with completion scheduled for late next year.