초록 ▼

A method is provided for the recovery of aromatic hydrocarbons from the extract phase of aromatic-selective solvent extraction process which involves withdrawing a vapor side-cut fraction containing aromatic hydrocarbons and solvent from a stripping zone and passing the side-cut fraction to a rectif

A method is provided for the recovery of aromatic hydrocarbons from the extract phase of aromatic-selective solvent extraction process which involves withdrawing a vapor side-cut fraction containing aromatic hydrocarbons and solvent from a stripping zone and passing the side-cut fraction to a rectification zone which can be refluxed with an aqueous condensate. The benefits of the invention are that the introduction of the rectification zone bottoms to the bottom of the stripping section provides an aromatic product comprising less than 100 wt. ppm. solvent, provides improved stripping over prior schemes, and reduces the flowrate of stripping medium throughout the stripping zone which results in energy saving.

대표청구항 ▼

In a method for recovering aromatic hydrocarbons from an extract phase from an aromatic-selective, solvent extraction zone which comprises the steps of: a) introducing the extract phase comprising aromatic hydrocarbons, non-aromatic hydrocarbons and aromatic-selective solvent into an upper section o

In a method for recovering aromatic hydrocarbons from an extract phase from an aromatic-selective, solvent extraction zone which comprises the steps of: a) introducing the extract phase comprising aromatic hydrocarbons, non-aromatic hydrocarbons and aromatic-selective solvent into an upper section of a stripping zone; b) introducing a stripping medium comprising rectification zone bottoms into the stripping zone; c) withdrawing from the upper section of the stripping zone a first vapor fraction comprising water and non-aromatic hydrocarbons; d) withdrawing from an intermediate section of the stripping zone a second vapor fraction comprising aromatic hydrocarbons, water and solvent; e) passing the second vapor fraction to a rectification zone; f) withdrawing from an upper section of the rectification zone a third vapor fraction comprising aromatic hydrocarbons and water; g) condensing the third vapor fraction to provide an aromatic hydrocarbon stream and a liquid water stream; h) passing at least a portion of the liquid water stream into the upper section of the rectification zone; i) withdrawing from a lower section of the rectification zone a rectification zone bottoms comprising solvent and water; j) withdrawing from a lower section of the stripping zone a stripper bottoms stream comprising aromatic selective solvent; and k) reboiling a portion of a fluid at the bottom of the stripper and introducing the reboiled portion at a point in the lower section of the stripping zone; the improvement which comprises maintaining a weight ratio of the water to the aromatic hydrocarbons in the second vapor fraction to a value of between about 0.05 and about 0.3; providing heat to the lower section of the rectification zone; withdrawing a majority of the water from the rectification zone bottoms and introducing said majority of the water to the lower section of the stripping zone at or near the point where the reboiled portion of the stripper bottoms is introduced; and recovering the aromatic hydrocarbon stream comprising less than 5 wt. ppm solvent.