HVO Producers

Hydrotreated vegetable oil (HVO), also sold as renewable diesel, is made by hydrodeoxygenating oils and fats over a catalyst and then isomerising the resulting paraffins to meet cold-flow targets. The product is a paraffinic diesel that can meet EN 15940 and be used neat or blended. Because the process removes oxygen rather than forming esters, an HVO unit accepts feedstocks that a conventional biodiesel plant struggles with, such as high free fatty acid (FFA) acid oils, animal fats and fatty acid distillates. It is far less tolerant, however, of the contaminants that poison hydrotreating catalysts.

What the process needs from the feedstock. Phosphorus, alkali and alkaline-earth metals, iron, silicon and chlorine deactivate catalysts or foul reactors, so HVO feed is normally pretreated by degumming, bleaching and filtration down to low single-digit mg/kg levels before it enters the unit. Nitrogen, which comes from proteins and phospholipids in animal fats and used cooking oil, inhibits the catalysts and consumes hydrogen. Chloride causes corrosion in the reactor section and downstream equipment. Polyethylene, which can enter used cooking oil and rendered fats from packaging, is specified by some refiners because conventional bleaching does not remove it.

Key specification parameters. HVO feedstock specifications typically cover FFA, moisture, impurities and unsaponifiables (MIU), iodine value, phosphorus, metals, chlorine, nitrogen, sulphur and, increasingly, polyethylene. High FFA is usually acceptable, but it makes the feed corrosive, so check the metallurgy of tanks and lines. Iodine value is less critical than in biodiesel because the reactor saturates the double bonds, although a higher iodine value raises hydrogen consumption. The oxygen content of the lipid, similar across most oils and fats, accounts for much of the hydrogen demand.

Recommended feedstock types. Waste and residue lipids dominate HVO feed slates because they carry the strongest regulatory value. Used cooking oil and category 1 and 2 animal fats are listed in Annex IX Part B of the Renewable Energy Directive, while palm oil mill effluent (POME) falls under Part A. Acid oils, distillers corn oil, PFAD and PKFAD are processed where national rules and the plant's pretreatment allow. Crude vegetable oils remain technically easy feedstocks but have lower regulatory value in many markets.

Documentation. Ask for lot-specific analysis covering the contaminants your pretreatment is designed to remove, the analytical methods used, and sustainability evidence that matches your compliance route, such as a proof of sustainability issued under a recognised scheme. The classification of residues varies between countries, so confirm the category your authority will accept before contracting, and ask for the certificate scope with your quotation.

Handling and shipping. HVO feedstocks move in bulk vessels, ISO tanks and flexitanks, and many of them need heating to discharge. Keep acid oils and fatty acid distillates in stainless steel or suitably lined tanks, do not mix lots that carry different sustainability classifications, and sample at loading and discharge so that contaminant results can be traced to a specific delivery.