The cold refining process is an alternative to winterization, preceded by neutralization. Use of the process is, however, confined to oils with a relatively low FFA content otherwise the oil losses are too high.
During the process a small amount of acid is added to the crude oil without prior heating. Once the oil has been thoroughly infused, and following a brief retention period, the oil is cooled. The caustic quantity required for neutralizing the free fatty acids is combined with the oil. The oil is then directed through crystallizers and housed for up to seven hours.
Following, the oil should be mildly heated to reduce the thickness before the soapstock is separated in a centrifuge along with the waxes. The dewaxed neutral oil has to be washed to reduce the soap content. Once the oil is heated, the required wash water quantity is added, and after thorough mixing with the oil, it is separated again in a second centrifuge. Finally, the oil is dried in a vacuum dryer.