Deodorisation and deacidification of salad oils, fats and ester(s) - by continuous countercurrent falling film vapour distn.

摘要

In the deodorisation and/or de-acidification of salad oils, fats and esters by continuous countercurrent falling film propellant vapour distn., where a liq. heated to 220-280 deg. C flows downwards under a pressure of 1-10 mbars and steam is fed in countercurrent, (a) the liq., after degassing and partial removal of water in a 1st column C-1, is fed at 260-270 deg. C and residual water content of 0.01% to the head of a flash column C-2, where 75-85% (at least 80%) of low-boilers are evaporated, (b) the low-boiler vapour from C-2 is fed through a film condenser F-6, where 20-50% is condensed, to a single- or multi-stage refining column C-3, at 180-190 deg. C, (c) in column C-3 the vapours from F-6, opt. with fatty acids vapours from a straight distn. C-6 and vapours from a unit arranged below this, are fed upwards in counter-current to condensate through a one- or two-stage reinforcement unit C-3/2 and C-3/1, (d) the vapours rising from C-3/2 and C-3/1 are washed in a condenser C-5, in countercurrent with condensate, and (e) the fatty acid stream taken off from the circulation-condensation stream of C-5 is treated by distillative purification, using stripping steam, in a stripper C-4 at 180-200 (190) deg. C, giving a fatty acid with purity above 99%. ADVANTAGE - The oil or fat recovered after the refining has less than 0.04% of residual fatty acid. Distribution of liq. over the cross-section of the falling-film distn. unit is uniform. Less steam is needed (0.224% in oil refining), reducing the operating costs.