Verfahren zur Trennung von Sauerstoffverbindungen von Kohlenwasserstoffen das Distillierung und Permeation sowie ihre Verwendung bei der Verätherung

摘要

The invention relates to a process for the separation of oxygenated compounds, comprising, mostly, methanol and optionally a minor part of water and/or of dimethyl ether, from a mixture of hydrocarbons, which can have 3 to 8 carbon atoms, containing the oxygenated compounds. A distillation stage of the mixture is carried out in a distillation region (D). A gaseous distillate (line 2) comprising methanol, optionally water, optionally dimethyl ether and hydrocarbons, is collected at the head of the distillation region. This gaseous distillate is separated by settling in a knockout vessel (B) and the collection is carried out (line 6) of at least one liquid organic phase, conveyed as reflux into the head of the distillation region D, and optionally of a liquid aqueous phase (line 5), as well as optionally of a gaseous phase (line 4). A phase is withdrawn laterally from the distillation region (line 8) and is conveyed into a permeation region (PV) comprising at least one membrane which is selectively permeable to methanol; a permeation stage of the said phase is carried out. The collection is carried out, downstream of the permeation region, of at least one permeate (line 14), preferably in the vapour phase, which is enriched in methanol and, upstream of the permeation region, of at least one retentate (line 11), which is optionally recycled in the distillation region, and the mixture of purified hydrocarbons (line 16) is withdrawn at the bottom of the distillation column.