Patent ID: 8338633

Claim:
A method of processing wood oil, which contains fatty acids, sterols and compounds with alcohol groups, for improving the yield of fatty acids and facilitating further processing of sterols, said wood oil being generated during pulping of a fibrous raw material, comprising adding to the wood oil a low molecular weight carboxyl acid in an amount of approximately 0.5-5.0% of the wood oil quantity (weight) in order to esterify, by using said acid, at least a part of the alcohol groups which are present in the wood oil and in order essentially to prevent esterification of said alcohol groups by the fatty acids naturally contained in the wood oil, and wherein the wood oil is obtained from the black liquor of the pulping, said carboxylic acid being added immediately after separation of wood oil from crude soap, before a significant portion of the alcohol groups have become esterified by the fatty acids naturally contained in the wood oil.