Patent ID: 7208570

Claim:
A method of refining the crude tall oil recovered from the pulping of pine wood with a known harvest time, according to which method the crude tall oil is fed into a column distiller, wherein it is separated into desired fractions, at least a part of which are recovered as a product flow, wherein the density of the crude tall oil fed into the column distiller and of at least one product flow is measured, the density is measured to an accuracy of at least 4 decimal places or, correspondingly, 5 significant figures as a function of the temperature, the compositions of the flows are calculated from the density values by using correlation functions derived from the chemical compositions of the flows, which correlation functions are obtained on the basis of previously performed laboratory analyses of corresponding flows using temperature compensation to specify the correlations, and taking into account the regular annual cycle variation in the wood composition of fresh wood, and the conditions of the column distiller are adjusted on the basis of the composition of the feed and the product flow.