Crude fatty acids are distilled under vacuum and high temperature in a packed column. The process removes odoriferous compounds and unconverted mono-, di- and triglycerides, producing distilled fatty acids suitable for further use. Bottom residues, known as pitch, are separated and sent to storage.

Fractional (thermal) distillation separates fatty acid mixtures into narrower cuts or pure fractions based on their different boiling characteristics. Feedstocks such as coconut oil, palm kernel oil, palm oil, soft oils, soybean acid oil, sunflower acid oil, mustard oil and rapeseed oil can be processed to yield specific fractions, including pure C8, C10, C12, C14, C16, C18, C22 as well as mixtures like C8/C10, C12/C14, and C16/C18.

The system consists of a deaerator, a fractionation column, heating system, condensing system and vacuum system. Fatty acids are heated gently in a falling film evaporator to ensure low residence time and minimise degradation. Vapours rise through a packed column with structured packing, which provides high surface area, excellent separation efficiency and low pressure drop. Fatty acid vapours are condensed in a surface condenser, with integrated steam generators recovering heat for improved efficiency. Fractional distillation of fatty alcohols and fatty acid esters can also be carried out in the same packed column towers, followed by cooling in condensers to deliver pure fractions or narrow cuts tailored to chain length requirements.

For highly unsaturated and heat-sensitive materials, fractional crystallisation separates fatty acids based on melting and solidification points rather than boiling characteristics. The process involves controlled crystallisation followed by membrane filtration, producing narrow cuts while avoiding thermal decomposition.