菜籽酸化油 — Frequently Asked Questions

Two sources add up. Rapeseed contains glucosinolates, and some of their sulphur-bearing breakdown products follow the oil and concentrate in the soapstock. Acidulation with sulphuric acid then adds residual acid and sulphate if washing is incomplete. Set a sulphur cap with a named low-level method, and check whether your esterification, ester distillation or hydrotreating can bring the product within its limit.

Rapeseed oil is low in saturated fatty acids, so its methyl ester has a comparatively low cold filter plugging point. Ester made from rapeseed acid oil broadly follows that pattern, which makes it a useful blend component for winter-grade biodiesel where palm-based or animal-fat esters would cloud too early.

Typically around 100–120 g I2/100 g, reflecting a profile rich in oleic acid with moderate linoleic and linolenic acid. That usually keeps the finished ester within the EN 14214 limit of 120, although the linolenic acid content still calls for attention to oxidation stability and, in many plants, an antioxidant dose.

Chlorophyll and its breakdown products can concentrate in soapstock and give the acid oil a greenish-dark colour. They can affect ester colour and stability and carry trace magnesium. Bleaching earth in pretreatment removes most of them, so buyers who run a bleaching step usually treat colour as a reported value rather than a contract limit.

It is not named in Annex IX, so it does not automatically count as an advanced or Part B feedstock. Its treatment as a processing residue or a co-product varies between Member States and schemes, and some aviation schemes restrict acid oils. Confirm the category your authority accepts and the certificate scope with your certification body before contracting.

Your TFM and MIU basis, FFA, iodine value, sulphur and phosphorus limits with test methods, the conversion route, volume, flexitank, ISO tank or bulk preference, delivery point and Incoterm, and the sustainability documents required for your market. If winter cold-flow performance is the reason for buying, say so, as it helps match suitable lots.