Sunflower Acid Oil

About This Product

Sunflower acid oil is produced when soapstock from the chemical refining of sunflower oil is split with a mineral acid, usually sulphuric acid. The neutralisation step converts the crude oil's free fatty acids into sodium soaps, which leave the refinery's centrifuges together with some neutral oil, phospholipids and water; acidulation turns them back into free fatty acids, and the recovered oil phase is traded as acid oil. It arises wherever sunflower seed is crushed and refined at scale. The key variable is which sunflower oil the refinery processed. Conventional, linoleic-type sunflower oil gives an acid oil with a high iodine value, often about 120–140 g I2/100 g, while high-oleic sunflower oil gives a far more monounsaturated profile with an iodine value nearer 80–90. Refineries that alternate between the two can produce lots that differ markedly, so iodine value should be measured on every lot rather than assumed. Sunflower oil also contains natural waxes from the seed hull, and depending on the refinery's sequence part of this material can reach the soapstock, where it appears as unsaponifiable matter or as haze and deposits when the oil cools. For biodiesel, FFA typically in the 50–80 % range requires acid esterification or glycerolysis ahead of transesterification. Ester from linoleic-type material is likely to exceed the EN 14214 iodine value limit of 120 unless blended, and needs antioxidant to meet the oxidation stability requirement; high-oleic material is easier on both counts. For HVO and HEFA-SPK (SAF), FFA is acceptable and the C18 profile converts well, but waxes, phosphorus, metals and sulphate should be reduced in pretreatment, with cooling and fine filtration where waxes are present. Contracts typically set TFM (often 90–95 % or more), MIU (commonly up to 3–5 %), FFA as % oleic acid, iodine value, sulphur and phosphorus, and HVO buyers add metals and chloride. Where waxes cause trouble, a cold test or a filterability measure at a stated temperature is a practical addition to the specification. Sunflower acid oil is not named in Annex IX of the Renewable Energy Directive. Under RED III it may be treated as a processing residue or as a co-product, depending on the Member State and scheme, and some aviation schemes restrict acid oils. Confirm the classification and certificate scope with your certification body, and ask for documents that identify the originating refinery and fit your mass-balance records. The oil is normally liquid at ambient temperature but can deposit waxy material in cold holds. Flexitanks with confirmed compatibility, lined or stainless ISO tanks and bulk parcels are all used, with light heating in cold conditions. In an enquiry, say whether conventional or high-oleic origin matters to you, and give your TFM, MIU, iodine value, sulphur and phosphorus basis, route, volume, packaging, delivery terms and documentation needs.