Hydrotreated Vegetable Oils (HVO) commonly referred to as renewable diesel and Hydroprocessed Esters and Fatty Acids (HEFA) are produced via hydroprocessing of oils and fats. Hydroprocessing is an alternative process to esterification to produce diesel from biomass.
HVO/HEFA are straight chain paraffinic hydrocarbons that are free of aromatics, oxygen and sulfur and have high cetane numbers. HEFA offers a number of benefits over FAME (Fatty Acid Methyl Esters), such as reduced NOx emission, better storage stability, and better cold flow properties. Hence HEFA can typically be used in all diesel engines. Also, the use as an aviation (bio jet) fuel has been approved.
HVO can be produced from a wide variety of materials containing triglycerides and fatty acids.
Within this range of materials, HVO is flexible in its feedstock requirements allowing the use of a wide range of low quality waste and residue materials still leading to production of hydrocarbon drop-in products. The key additional feedstock needed is hydrogen which today comes from a fossil source.
HVO type of biofuels can be produced by either investing in stand-alone facilities or by converting the existing oil refineries into HVO technology production or co-production facilities.
COMMERCIAL PRODUCTION OF HVO/HEFA
Stand-alone production facilities
Currently, 3.5 million tonnes per year of HVO production takes place globally expected to increase to 6-7 million tonnes per year by 2020. In the EU, further refinery conversions and co-
processing have the potential to provide additional biofuel volumes in the range of 12 million tonnes. Neste was the first to invest in an HVO refinery (Porvoo 2007). Currently, Neste has a production capacity of 2.4 million tonnes per year, with stand-alone refineries in Porvoo (Finland), Singapore and Rotterdam (the Netherlands).
In the US, Diamond Green operates a HVO stand-alone facility of 430 thousand tonnes per year and in Finland UPM operates since 2015 their HVO refinery of the capacity of 100 thousand tonnes per year. In addition, in the US, Renewable Energy Group has a (currently idle) HVO facility of 225 thousand tonnes, and Emerald Biofuels plans to invest in a facility of 250 thousand tonnes in 2018.
Production through refinery conversion
There is a large number of traditional oil refineries in the EU with refinery technology suitable for HVO conversion, as they have two hydrotreaters which were originally designed for removal of sulphur and nitrogen from fossil feeds by hydrogen treatment. Already ENI S.P.A (ENI) has converted their Venice refinery to 0.3 million tonnes of HVO, and a refinery in California has been converted by Altair to 0.2million tonnes output. A second ENI refinery, Gela in Sicily is being converted to 0.5million tonnes product, as is the Total refinery at La Mede, France.
In addition to the 100% HVO production, biofuels can be produced through co-processing. In co-processing, biomaterial is fed into refinery units together with fossil feeds typically in low (<5%wt-10%wt) blends, but higher blends are in use by e.g. Preem in Sweden. As the refinery processes are complex and units interlinked, co-processing bio-feeds in integrated refinery lines results in fractionation of bio-components in multiple products streams.
Co-processing already takes place in the EU, but detailed information about co-processed bio-volumes are not publicly available. A rough estimation of the volume potential of co- processed biofuels could be that if 30% of EU refining capacity (230 million tonnes year) would use 5% bio-feed, the resulting biofuel volume would be in the range of 3.5 million tonnes per year.
At least Preem in Sweden has production of 200,000 tonnes through co-processing, and Repsol and Cepsa in Spain are estimated to produce co-processed biofuels in the scale of approx. 60,000 tonnes each while ConocoPhillips is also co-processing in Cork, Eire.
USE OF HEFA AS AN AVIATION FUEL
HEFA is approved for use as an aviation fuel under ASTM D7566-14, Specification for Aviation Turbine Fuel Containing Synthesized Hydrocarbons. A revised standard was approved on July 1, 2011 allowing up to 50 percent bioderived synthetic blending components (HEFA) to be added to conventional jet fuel. HEFA is also an important component of the European Advanced Biofuels Flight Path Initiative.