Exxon Research and Engineering Company

Other

John A Thompson

Theodore H West

David H Shaw

David A Gudelis

Patrick C Ewener

Louis C Dallaire

Medi M Hafez

Brian B Adams

Duncan J Bristow

Scott W Armstrong

Manual E Camano

Hard asphalts exhibiting acceptable penetration and low temperature properties can be produced from vacuum residua from which such hard asphalts are not normally obtainable via typical vacuum distillate such as that derived from Arab Light crude and/or feeds substantially comprising Arab Light-type crudes by ultrafiltering the residua through a membrane.

Production of hard asphalts by ultrafiltration of vacuum residua

The present invention is a flat stack permeator useful under dialysis, ultrafiltration, reverse osmosis, perstraction, pervaporation, etc. conditions. The permeator comprises a multitude of membrane layer alternately separated by feed-retentate spacers and permeate spacers. The layers are secured along their edges so as to define separate feed-retentate zones and permeate zone. The edge gluing is performed so that in any given layer the two parallel edges are secured, while on the layers immediately above and below the edge pairs which are secured are 90.degree. out of register with the previously mentioned pair of secured edges. In that way alternate feed retentate and permeate zones are defined which are perpendicular in flow one to the other. This stack of membrane and spacer layer is fabricated between flat rigid, solid, non-permeable sheets, the membrane sheets immediately adjacent to said solid sheets being edge glued to the sheet along the proper edge defining a feed-retentate or permeate zone as appropriate to form a module. This module is fitted with manifolds to provide a feed-retentate entrance-exit pair and separate permeate exits. Alternatively the module can be inserted into an appropriately manifolded pressure vessel.

Flat stack permeator

A method is disclosed for the in-situ repair of damaged filter cloths in solvent dewaxing filters. The damage that can be repaired can be either or both of tears or holes. The method comprises thoroughly washing the filter cloth in the area of the damage to remove wax and oil, applying a quantity of solvent resistant adhesive to the damaged area such that the area of treatment extends beyond the hole or tear and adhesive overlays onto undamaged cloth, inserting pre-cut portions of filter cloth into the damage so as to completely fill the hole or tear but not create a bulge or cloth buildup in the face of the filter cloth where required and, finally, and optimally applying a final coating of adhesive over the repaired area.

Method for in-situ repair of solvent dewaxing filter cloths

Described is a membrane apparatus having particular application in hydrocarbon processes, such as separating ketone dewaxing solvent from a hydrocarbon process stream. The apparatus contains a pressure resistant compartment containing flattened tubular membranes in a parallel stack arrangement separated by retentate spacers. Internally each tube contains permeate spacers for solvent outflow which permeate spacers extend the full length of the tubular membrane. The end of the tubes are not separated by retentate spacers and are clamped together such that solvent exits via the permeate spacers, while the clamping assembly design prevents the cocurrent exit of solution from the high pressure compartment at the solvent inlet location.

Multi-leaf membrane module

Polycarbonate membranes are prepared for the selective separation of organic liquid mixtures, especially for the separation of ketone dewaxing solvents from dewaxed oil by preshrinking said membranes in presence of a class of solvents of solubility parameter values in the range of from 8.9 to 10 (cal/cm.sup.3).sup.0.5, and which do not dissolve the membranes. Preshrunk polycarbonate membranes, prepared by the method of the present invention, can be used for the selective separation of the various components in organic liquid mixtures such as, for the separation of dewaxing solvents from dewaxed oil, preferably the separation of ketone dewaxing solvents from dewaxed oil. The separation is based on a reverse osmosis technique whereby the solvent is permeated through the membrane under an applied pressure sufficient to overcome the osmotic pressure of the system. Applied pressures can vary from 50 up to 1,500 psi, depending on solution concentration. The separation can be carried out in the temperature range -30.degree. to about +80.degree. C., preferably about -20.degree. to about +60.degree. C.

Method for the modification of polycarbonate membranes, the membranes

Selective extraction solvents such as NMP, phenol or furfural employed for the extraction of specialty oils, i.e. lubricating, transformer and insulating oils, to remove undesirable aromatic components therefrom, is itself recovered from the extract stream and/or raffinate streams by preferential ultrafiltration through selective membranes of regenerated cellulose. The extract stream, because of its higher solvent content, is the preferred stream for solvent recovery treatment by the reverse osmosis membrane permeation technique. Solvent recovery employing membrane permeation exhibits the advantage of not being energy intensive as is distillation or stripping. The solvent is recovered at a high enough flux rate and at a high enough level of purity to be introduced back into the solvent extraction process optionally at some point in the process wherein the composition of the recovered solvent approximately matches the composition of the solvent present in the process at the point of introduction.

Selective extraction solvent recovery using regenerated cellulose

A method for separating a mixture into a first fraction and a second fraction is disclosed. The method comprises passing the mixture into a decantation zone where the solution is separated into a first fraction relatively rich in a first compound and a second fraction relatively deficient in the first compound. One of the separated fractions subsequently is passed to a membrane separation zone for further purification. The subject invention is of particular utility in petroleum processing, where the solution passed to the decantation zone may be a petroleum processing fraction, such as filtrate from a dewaxing zone or an extract or raffinate from an extraction separation zone.

Membrane separation process

A warm-up deoiling process for lube oil slack wax wherein cold slack wax from a solvent dewaxing operation is warmed up and mixed with solvent to dissolve foots oil contained therein and passed to a rotary drum filter to recover solid wax and a filtrate comprising a solution of foots oil and solvent wherein said filtrate is contacted with one side of a semi-permeable membrane made from regenerated cellulose which selectivity permeates at least a portion of solvent through said membrane and recycling the permeated solvent directly back into the warm-up deoiling operation as part of the solvent mixed with the slack wax.

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Wyoming, Canada

John A Thompson