Abstract: Distillate or hydrotreated distillate effluent is separated into an aromatics rich permeate and an aromatics lean retentate by use of a permselective membrane with the aromatic rich permeate being sent to a hydrotreater, thereby increasing the quantity of reduced aromatics content product.

Abstract: The yield and quality of products secured from cracking units is increased by the process of subjecting the product stream secured from such cracking unit to a selective aromatics removal process and recycling the recovered aromatics lean (saturates rich) stream to the cracking unit whereby such saturates rich stream is subjected to increased conversion to higher value desired products.

Abstract: The pervaporative treatment of hydrocarbon feeds which have been exposed to air or oxygen and which contain mixtures of aromatic and non-aromatic hydrocarbons to selectively separate the feed into an aromatics rich stream and a non-aromatics rich stream is improved by the step of pretreating the hydrocarbon feed over an adsorbent such as attapulgite clay.

Abstract: Mixtures comprising alcohol/ether/non-linear hydrocarbon are separated using polyester or polyester polyimide copolymer membranes. The mixture is contacted under pervaporation conditions with the membrane and the alcohol selectively permeates through the membrane. In this way alcohol especially C.sub.1 -C.sub.10, preferably C.sub.1 -C.sub.4 alcohols can be effectively removed from the synthesis solutions used for the production of high value ethers such as methyl-tertiary butyl ether (MTBE) or tertiary-amyl methyl ether (TAME) used as octane enhancers in motor fuels.

Abstract: A multi-element housing is disclosed for the containment of multiple membrane separation elements in parallel. The multi-element housing is characterized in that the elements are grouped in parallel with a feed/retentate zone, defined by a space enclosed by two tube sheets arranged at the same end of the elements. The central mandrels of the elements pass through the feed/retentate zone space defined by the two tube sheets and empty permeate outside the defined space into a permeate collection zone from which it is removed, while the tube sheet directly attached to the element is in open relationship to the interior of the membrane element and retentate accumulates in the space between the top tube sheet and the bottom tube sheet from which it is removed.

Abstract: A hollow fiber permeator is described which permits counter-current flow in the passage of feed/retentate and permeate-sweep streams. The permeator comprises a bundle of hollow fibers compartmentalized using a series of concentric shells or a spiral wrap extending the entire length of the hollow fibers. The rings or spiral wrap are perforated along the top and bottom to permit even flow distribution through each of the compartments defined by the concentric rings or spiral wrap so that the linear flow rate down the length of the permeator is similar for each compartment.

Abstract: The present invention is a process for the recovery of normal alcohols, especially C.sub.1 -C.sub.20 n-alcohols, preferably n-C.sub.4 -C.sub.14 alcohols, most preferably n-C.sub.6 -C.sub.11 alcohols from n-paraffins by means of pervaporation through a membrane. The alcohols/paraffin feed mixture may be that produced in the Fischer-Tropsch synthesis process wherein mixtures of CO and H.sub.2 are reacted to produce paraffin waxes and a minor but still valuable amount of alcohols.

Abstract: Hollow fiber membrane separation elements are improved with respect to fluid flow and contacting by dividing the bundle of hollow membrane fibers in the element into discrete sub-bundles by use of baffles in the module.

Abstract: Improved separation of feed streams containing multiple components is effected by means of a multi membrane staged pervaporation process wherein each membrane stage is series is run as progressively higher temperature, stronger vacuum or both than the preceding stage. This process is especially useful for separating components from wide boiling range mixtures.