NOVELTY - Water and/or methanol are removed from a feed composition comprising a product component and the contaminant, by using a membrane separation system comprising membrane(s) (5) comprising a permeable layer comprising a perfluoropolymer.    USE - For removing contaminant from water and/or methanol, from a feed composition comprising a product component and the contaminant.    ADVANTAGE - The method is compact, light weight, low power-consuming and simple to operate in remote regions distant from sources of power, utilities and/or waste regeneration and disposal facilities.    DETAILED DESCRIPTION - Removing contaminant from water and/or methanol, from a feed composition comprising a product component and the contaminant, comprising:    (A) providing a membrane separation system comprising membrane(s) comprising a permeable layer comprising a perfluoropolymer;    (B) introducing the feed composition into the membrane separation system and contacting the feed composition in which the contaminant is present at an initial concentration with the membrane;    (C) applying a driving force across the membrane to cause permeation of the feed composition through the membrane in which the contaminant transfers through the membrane preferentially relative to the product component, thus removing contaminant from the feed composition; and    (D) recovering from the membrane separation system a product composition comprising the contaminant at a final concentration lower than the initial concentration.    INDEPENDENT CLAIMS are included for:    (1) a method of conducting a reversible chemical reaction to make a reaction product and a byproduct comprising providing reactants for the chemical reaction in which the byproduct is water and/or methanol; reacting the reactants to form a reaction mass comprising the reaction product, the byproduct and residual reactants which define a first extent of conversion of reactants to the product; contacting a membrane comprising a permeable layer comprising a perfluoropolymer with the reaction mass; applying a driving force across the membrane to permeate the byproduct and to retain a reaction mass depleted of the byproduct relative to the reaction mass of the second step; continuing the chemical reaction of the reaction mass depleted of the byproduct; collecting reaction mass defining a second extent of conversion of reactants to the product greater than the first extent of conversion; and optionally, adding reactants to the reaction mass; and    (2) a pipeline ethanol drying system comprising a fluid transfer line, membrane separators comprising a membrane, and heaters.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic flow diagram of a one stage vapor permeation dryer.    Feed stream (1)    Heater (2)    Membrane module (4)    Membrane (5)    Feed-retentate chamber (6)    Permeate chamber (7)