| 摘要 |
<p>Aromatic hydrocarbons contained in a mixed hydrocarbon feedstock are separated by (a) contacting the feedstock with a primary (1 degree) solvent in a primary (1 degree) extractor at a temp from ambient to 175 degrees C and at 15-200 psia, the (1 degree) solvent being a water-soluble organic solvent of higher b.p. than and non-azeotropic with the feedstock; (b) withdrawing a (1 degree) solvent aromatic hydrocarbon extract phase (1 degree extract) and a non-aromatic raffinate (1 degree raffinate); (c) contacting the (1 degree) extract with a secondary (2 degrees) solvent in a (2 degrees) extractor under temp and pressure conditions similar to those in the (1 degree) extractor, the (2 degrees) solvent consisting of paraffin or naphthenic hydrocarbons of higher b.p. than and non-azeotropic with the initial feedstock; (d) withdrawing a (2 degrees) extract consisting of (2 degrees) solvent, aromatic hydrocarbons and (1 degree) solvent and distilling it to recover aromatic hydrocarbons; (e) distilling the (1 degree) raffinate, and (f) recycling to the (1 degree) extractor (1 degree) and (2 degrees) solvents from the distillation of (2 degrees) extractand (1 degree) raffinate. The process permits benzene to be recovered in a purity of 99.9% and tolune and xylenes in a purity of 95% or higher.</p> |
