Continuous shell still process

In the continuous shell still process, several shell stills are linked in series to form a battery. Fresh feed continuously enters the first still, which is kept at the lowest temperature for the lightest overload produa. The bottoms from the first still are fed to the second still, which is kept at the temperature for the next highest boiling overhead product, and so on. The number of stills required depends on the number of produas needed. If the feed and the temperature of each still remain constant, the finished product is of satisfaaory quality. Exhibit 10-3 depicts the continuous shell still process, which is an improvement over the batch shell still operation. 

Similar to the continuous shell still, the fractional distillation process is made up of several stills linked together in series. The main diflference is that all the liquid condensate is returned to the upstream still. As the feed is partially vaporized in the first still, the va-... 

It is apparent that around 1925 distillation equipment in the petroleum industry varied in design and complexity from the simple horizontal shell stills with fractional vapor condensation to the continuous pipe stills with the progenitor of the present bubble cap fractionating columns. The basic processing principles were being rapidly extended, and the foundation was well established for the further development of distillation technology. 

Shell Stills. At the beginning of the period under review, large quantities of crude oil were processed in tower stills. These were cylindrical vessels 10 to 15 feet in diameter and about 40 feet long. The vessels were mounted horizontally and arranged so that a fire could be applied to the underside (10, 55). The stills were charged with crude oil and the appropriate fractions removed by distillation. The residue was then destructively distilled or coked. Heating was continued until the bottom of the still was at a dull red heat (55). 

The anacardic acids in the natural CNSL of the raw nut shell are decarboxylated and the resultant cardanol liberated supplements the hot technical CNSL in the bath through the bursting of the outer shell and, after an ideally short period, flows continuously out of the system. The spent processed nuts with the inner shell still intact also pass out of this system and after removal of the superficial CNSL by centrifugation or adsorption are shelled by an automatic procedure in Brazilian and East African technology or manually in Indian practice. 

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