CPC C11B 3/12 (2013.01) [C10G 3/50 (2013.01); C10G 2400/02 (2013.01); C10G 2400/04 (2013.01); C10G 2400/08 (2013.01); C10G 2400/26 (2013.01)] | 22 Claims |
1. A method for refining crude tall oil, characterized in that the method comprises
(a) evaporating tall oil material (10) in a first evaporator (100) at a temperature between 255 and 295° C. and a pressure between 80 and 220 mbar to obtain a first fraction (11) comprising crude sulphate turpentine, light fatty acids, light neutrals, silicon compounds and water and a second fraction (12) comprising fatty acids, resin acids, neutral substances and residue components;
(b1) evaporating said second fraction (12) in a second evaporator (110) at a temperature between 230 and 270° C. and a pressure between 5 and 20 mbar to obtain a third fraction (13) comprising fatty acids, resin acids and light neutral substances, and a first concentrate fraction (14); and evaporating said first concentrate fraction (14) in a third evaporator (120) at a temperature between 280 and 320° C. and a pressure between 5 and 20 mbar to produce a fourth fraction (16) comprising fatty acids, resin acids and light neutral substances, and a residue fraction (15); or alternatively
(b2) evaporating said second fraction (12) in a second evaporator (110) at a temperature between 300 and 340° C. and a pressure between 3 and 10 mbar to obtain a third fraction (13) comprising fatty acids, resin acids and neutral substances and a residue fraction (15);
whereafter the method further comprises
(c) distilling said first fraction (11) in a first distilling column (200) to obtain at least a crude fatty acid fraction (20);
(d) distilling said third (13) and said fourth fraction (16) of step (b1) or said third fraction (13) of step (b2) in a second distilling column (300) to obtain at least a crude fatty acid fraction (30); and
(e) recovering a combined crude fatty acid fraction (40) from said first distilling column (200) and said second distilling column (300).
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