| Abstrakt: |
A batch co-current laboratory method for measuring comparative extraction rates and extraction efficiencies of oleaginous materials in solvent is described. The method, a modification of that by Winward and Shand, was carefully tested with raw and cooked cottonseed flakes of various thicknesses and in various hexane miscella concentrations. It enables measurement of intrinsic extraction rates and extractabilities of materials, unaffected by diffusional effects in the liquid medium, and yields accurate and concordant results even with extracting miscellas of considerably high concentration. It is equally applicable for evaluating and predicting the effect upon extractability of different material preparation operations, particle sizes, moisture contents, temperature, solvents, etc. The method was used in this investigation to compare the rate and degree of extraction under the specified testing conditions of raw and cooked cotton-seed flakes of .005-in., .015-in., and .025-in. thicknesses in miscella concentration of 0%, 25% and 50% oil. The results may be summed up as follows:the extractability of both raw and cooked flakes in each of the miscella concentrations decreases as the flake thickness increases.the cooked material prepared from the medium and thick flakes extracted at a more rapid rate and to a greater degree in all miscella concentrations than the raw flakes of comparative thicknesses, but the rate and degree of extraction were about equal for the very thin flakes.the effect of increasing miscella concentration for both the raw and the cooked flakes of medium and thick sizes was to slow down the initial extraction rate; but for the very thin flakes the effect was negligible.the effect of increasing miscella concentration in extracting the cooked material, regardless of flake thickness, was to increase the degree of extraction. For the raw flakes the effect was to increase the degree of extraction only of the very thin flakes. the extractability of both raw and cooked flakes in each of the miscella concentrations decreases as the flake thickness increases. the cooked material prepared from the medium and thick flakes extracted at a more rapid rate and to a greater degree in all miscella concentrations than the raw flakes of comparative thicknesses, but the rate and degree of extraction were about equal for the very thin flakes. the effect of increasing miscella concentration for both the raw and the cooked flakes of medium and thick sizes was to slow down the initial extraction rate; but for the very thin flakes the effect was negligible. the effect of increasing miscella concentration in extracting the cooked material, regardless of flake thickness, was to increase the degree of extraction. For the raw flakes the effect was to increase the degree of extraction only of the very thin flakes. |
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