US PATENT SUBCLASS 208 / 350
.~.~ Rectification

Current as of: June, 1999
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208 /   HD   MINERAL OILS: PROCESSES AND PRODUCTS

308  DF  FRACTIONATION {5}
347  DF  .~ Distillation {12}
350.~.~ Rectification {7}
351  DF  .~.~.~> C1-C4 alkane removal
352  DF  .~.~.~> Flash vaporizaton
353  DF  .~.~.~> With heat recovery by indirect heat exchange
354  DF  .~.~.~> Plural or combined with additional distillation {1}
356  DF  .~.~.~> With added gas or vapor (e.g., steam)
357  DF  .~.~.~> Vacuum or pressure
358  DF  .~.~.~> With liquid product recycle to rectification zone

DEFINITION

Classification: 208/350

(under subclass 347) Processes carried out in such a manner that vapor rising from the still comes into contact with a descending condensed portion of vapor previously evolved from the still.

(1) Note. In rectification processes the refluxing condensate scrubs the higher boiling mineral oil constituents from the vapor stream, and at the same time is itself

stripped of a portion of its content of low boiling mineral oil constituents.

SEE OR SEARCH CLASS

202, Distillation: Apparatus,

153+, and 158+ for distillation apparatus including a fractionating column.

203, Distillation: Processes, Separatory, appropriate subclass, for a separatory distillation process, and note particularly, 75, 82, 93, 94, 97, and 98 for a distillation process in which a separated condensate is returned to the distillation zone.