| 摘要 |
The combined in-line bleaching and dewaxing of vegetable oils (I) is as follows: (a) (I) is bleached with a bleaching clay (II) and filter aid (III) for 15-60 min. at 80-130 deg.C (b) the prod. contg. (II) is rapidly cooled to 0-15 deg.C for 0.25-4hr. to effect dewaxing; (c) the spent (II), waxy material and other impurities are sepd. at 0-20 deg.C and (d) bleached, dewaxed (I) is recovered. - Pref. step (a). uses milo, rice bran, sunflower, safflower, esp. corn or rapeseed (canola) oils as (I). Amt. of (II) is 0.5-5 % by wt. of (I). Wt. ratio (III):(II)= 5-50:100 esp. 1:3. Bleaching is pref. in vacuo with agitation for 15-60 min. at 100-110 deg.C in the presence of 85% H3PO4 (0.04-0.12 % by wt, of (I)). Step(b). Cooling is with average temp. gradient 10-20 esp. ca 15 deg.C/min. to 5-10 deg.C. Opt. prior to step (a), (I) may be degummed at low temps. then pref. dried to H2O-content less than 0.1 wt.% or alkali refined; then pref. dried to H2O-content less than 0.1 wt.%.
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