TH35948A - Methods for the recovery of pure hydrocarbons from aromatic and non-aromatic hydrocarbon mixtures. (non-aromatic) - Google Patents

Abstract

DC60 (17/02/42) A process for the recovery of pure hydrocarbons from hydrocarbons, especially, highly aromatic hydrocarbon mixtures, by extraction in an extractive distillation column. The first sub-flow of a selective solvent is fed between the upper and lower sections of the column. The selective solvent used is N-substituted morpholine (a type of morpholine with a nitrogen atom substituent). Non-aromatic compounds are extracted as raffinate at the top of the extractive column, and aromatic compounds and the selective solvent are extracted as extracts from the lower basin. A second sub-flow of the selective solvent is fed through the second feed into the upper section of the column, above the first feed. The amount of solvent supplied to the second sub-flow comprises less than 50% of the total solvent volume. In processes for the recovery of pure hydrocarbons, particularly aromatic hydrocarbon mixtures, by extractive distillation in an extractive distillation column, the first solvent feed for the first sub-flow of the selective solvent is fed between the upper and lower sections of the column. The selective solvent used is N-substituted morpholine. The non-aromatic compounds are extracted as raffinate at the top of the extractive distillation column, and the aromatic compounds and the selective solvent are extracted as an extract from the lower basin. This indicates that a second sub-flow of the selective solvent is then fed through... A second solvent feed is administered to the top of the tower, above the initial feed, and the amount of solvent provided for this second feed is less than 50% of the total solvent volume.

Claims (7)

1. A process for recovering pure hydrocarbons from aromatic and non-aromatic hydrocarbon mixtures, especially from mixtures with a high aromatic content, by extractive distillation in an extractive distillation column where a second sub-flow of the selective solvent is introduced into the upper part of the column above the initial feed. At least N-substituted morpholine is used as the selective solvent, and non-aromatic compounds are extracted as raffinates at the top of the column, while aromatic compounds and the selective solvent are extracted as extracts from the lower basin. This indicates the introduction of a second sub-flow of the selective solvent into the column. This is achieved by a second solvent feed into the uppermost section of the tower, above the initial feed, and the amount of solvent supplied to this second secondary feed is less than 50% of the total amount of solvent supplied to the first and second secondary feeds. 2. The process pursuant to claim 1 indicates that the aromatic hydrocarbon blend used contains more than 85% aromatics. 3. The process pursuant to claim 1 or 2, which indicates the characteristics of N-substituted morpholin with no more than 7 carbon atoms in the substituent groups, shall be used as a selective solvent. 4. The procedures outlined in claims 1 through 3 indicate that N-formyl morpholin is used as a selective solvent. 5. The process described in claims 1 through 4 indicates that the aromatic extract and selective solvent, separated from the lower basin of the extraction column, are fed into a stripper column, and the aromatic extract is separated from the selective solvent in the stripper column. 6. Any of the claims under clauses 1 through 5, which characterize that the selective solvent extracted from the lower basin of the extraction column is recirculated and re-fed into the said extraction column through a solvent feed. 7. Any procedure under claims 1 through 6 that characterizes the amount of solvent supplied to the sub-flow to consist of 0.5 to 10% of the total amount of solvent supplied to the first and second sub-flows (7 claims, 2 pages, 2 figures).