Citric acid and other anti-oxidants are best-added on-line at the cooling stage after deodorization i.e. at temperatures of 120ºC or lower. It is important to ensure complete dispersion and dissolution of antioxidants in the oil by the incorporation of a static mixer in the line. Citric acid is of course acidic, and therefore if it is not properly mixed, the build-up of localized concentrations could be detrimental to the tank coatings or to mild steel tank walls.
Palm oil products in palm oil production process