Patent ID: 9567549
Date: 2017-02-14
CPC Classifications: B01D,C11B

Claim:
1. A process for deodorizing edible oil by a semi continuously operating steam distillation plant, comprising a stripping column with a plurality of separating stages configured to be shut off against each other, which are arranged therein, a degassing stage upstream of the stripping column and a downstream vapor scrubber, a vacuum generating plant connected with the degassing stage, the separating stages, and the vapor scrubber, one supply conduit each for stripping steam, which opens into the degassing stage and the separating stages, indirect heat exchanger surfaces each arranged in the separating stages of the upper and the lower portion of the stripping column, and a vapor discharge conduit opening into the vapor scrubber, which is connected with the separating stages arranged in upper and lower portions of the stripping column, the process comprising: (i) first, generating a vacuum of 2 to 7 mbar in the distillation plant; (ii) filling the degassing stage with a batch of feedstock edible oil; (iii) automatically passing the batch through the degassing stage and the separating stages, one after the other, after predetermined retention times of 20 to 40 min per stage controlled in dependence on performance; (iv) preheating the batch in the degassing stage with stripping steam to a temperature of 75 to 80° C., to obtain a preheated batch; (v) heating up the preheated batch to a temperature of 150 to 180° C. in the separating stages of the upper portion of the stripping column, to obtain a first heated portion; (vi) heating up the first heated portion in the separating stages of a middle portion of the stripping column to a temperature of 230 to 260° C., to obtain a second heated portion; (vii) cooling the second heated portion in the separating stages of the lower portion of the stripping column to a temperature of 90 to 120° C.; (viii) washing and condensing vapors discharged from the separating stages of the upper and the lower portion of the stripping column in the vapor scrubber with circulating sprayed fatty acid, to obtain a fatty acid mixed distillate; (ix) indirectly heating at least the hatch present in a downstream first separating stage of the middle portion of the stripping column with high-pressure steam; (x) indirectly cooling vapors discharged from the separating stages of the middle portion of the stripping column in at least a first condensation stage, a second condensation stage, and a third condensation stage; and (xi) fractionating in pure-grade form, condensed vapors, from the indirectly cooling (x), into a first fatty acid phase rich in sterols and tocopherols and a second fatty acid phase poor in sterols and tocopherols, wherein, in the third condensation stage, edible oil droplets entrained by the vapors are separated off.