BACKGROUND AND SUMMARY OF THE INVENTION Hydrocarbons having a carbon-carbon double bond are known as olefins.

Hydrocarbons having a carbon-carbon triple bond are known as alkynes. Olefins and alkynes are inherently unstable, and when present in lubricating oils, fuels, etc., often spontaneously polymerize or otherwise react to form sludge and other contaminants.

The process of placing two hydrogen atoms across a carbon-carbon double bond or four hydrogen atoms across a carbon-carbon triple bond is known as olefin saturation or hydrogenation. Hydrogenation changes an olefin and/or an alkyne to an alkane. Since alkanes are inherently more stable than olefins or alkynes, the saturation of all olefins and alkynes present in lubricating oils, fuels, etc., is highly desirable.

Olefin and alkyne saturation is also desirable in other circumstances. Ethylene is the simplest and most prevalent of the olefins. Ethylene is used in the manufacture of polyethylene which is the most prevalent of the plastics. Following polymerization, it is desirable to saturate any remaining olefins.

Another circumstance in which olefin saturation is desirable is in the manufacture of synthetic lubricants, such as polyalphaolefins. In manufacturing polyalphaolefins, alphaolefins are reacted with each other to form compounds of two or more alphaolepfins known as oligomers. Once formed, the oligomer often contains a residual carbon-carbon double bond which must be saturated.

The objective of olefin saturation has been accomplished in the past, but only by means of complicated, expensive, and inherently dangerous operations.

Co-pendin application serial no. 09/418,447 filed October 19,1999, and assigned to the assignee hereof discloses a method of olefin saturation in which a hydrocarbon stream including olefins and/or alkynes is treated with hydrazine and hydrogen peroxide in the presence of a catalyst. Preferably, the catalyst comprises a copper salt. The method also involves the use of a surfactant which serves to increase the surface area of the oil/water interface. Following the reaction, the surfactant is removed.

Although generally successfully in practice, the method of co-pending application serial no 09/418,447 involves certain difficulties.

Diimide is produce through the interaction of hydrazine with a copper (II) salt catalyst. Once formed, the diimide is capable of selectively saturating certain multiple bonds between carbon atoms and between carbon and other atoms. Unfortunately, a diimide species is also capable of interacting with another diimide species to regenerate hydrazine and nitrogen. Thus, hydrazine is typically required in much greater than stoichiometric amounts to ensure adequate reaction of diimide with an olefinic system.

However, the addition of greater amounts of hydrazine is of diminished value as the occurrence of the undesirable diimide-diimide reaction is rendered more probable. An alternative to the addition of a large excess of hydrazine is to run the reaction over a longer period of time by slowly delivering hydrazine into the reaction medium.

The present invention consists of immobilizing the copper catalyst on a cation exchange resin. While several cation exchange resins are suitable, the preferred resin

is a highly cross-linked polymeric resin that has been derivatized to include a large number of sulfonic acid sites, for example, poly (styrene-divinylbenze) resin. The high cross-linking of the resin serves to prevent the resin from swelling in the presence of the emulsion. The capacity of the resin, that is the number of sulfonic acid exchange sites, may be varied to ensure proper wetting by the emulsion. Likewise, the strength of the emulsion may be varied so as to complement the resin capacity to ensure proper wetting.

While the resin may be simply suspended in solution, the preferred embodiment of the invention uses a cation exchange resin packed into a column, through which a preformed emulsion is pumped. The preformed emulsion consists of the organic medium containing the unsaturated species, water, hydrazine and an inexpensive surfactant, preferably an anionic surfactant.

Another advantage of our invention over that of the prior art is the ability of the resin to contain a relatively large amount of the copper catalyst. Larger amounts of the copper catalyst result in a very short reaction time without suffering the diimide-diimide reaction problem previously described.

Air or another oxidizing reagent, such as hydrogen peroxide, may be added to the emulsion. The oxidizing reagent serves to continuously regenerate the copper (II) catalyst, which is reduced to copper (I) upon the formation of diimide.

Yet another advantage of the invention results from use of the preferred embodiment of the invention wherein the reaction takes place in a column packed with the ion exchange resin. In accordance with the preferred embodiment the resin is in the

form ofbeads, ranging in size rom S to 100 microns or greater, whi h serves to generate highly turbulent flow in the delivered emulsion. The turbulent flow allows the superior contact between the generated diimide and the species to be saturated, resulting in even faster reaction times. Additionally, the turbulent flow reduces the required amount of surfactant leading to an emulsion that is easily broken in a clarifier that receives the emulsion following its residence in the packed column.

After clarification, the aqueous phase of the broken emulsion is recycled for use with additional organic material contaminated by the unsaturated species, while the organic phase of the broken emulsion can be processed further, for example by distillation or extraction.

The invention is particularly suited for the recovery of distillate fuels that have aged and degraded beyond the point of safe utilization. When distillate fuels, especially those that have not been subj ected to refinery processes such as reforming or alkylation, are stored, contaminants such as olefins, organic peroxides, water and bacteria tend to collect. If aged fuel is used in an engine, the engine may be severely damage.

Obviously, this is an undesirable result, especially when the fuel is used in aviation engines.

Unfortunately, many distillate fuels, especially those destined for military use, are stored to the point at which they are no longer usable. Removing water and bacteria from aged fuel is easily accomplished through distillation. However, olefins and

organdi., peroxides that form in aged fuel are not easily removed through the distillation method.

Subjecting aged fuel to treatment through the saturation method of the present invention removes organic peroxides, olefins, and alkynes from the fuel. The saturation methodology is easily practiced in a continuos process prior to the ultimate distillation of the fuel.

BRIEF DESCRIPTION OF THE DRAWINGS A more complete understanding of the present invention may be had by reference to the following Detailed Description when taken in conjunction with the accompanying Drawings wherein : FIGURE 1 is a diagrammatic illustration of the formation cf diimide from hydrazine and air or oxygen; FIGURE 2 is a diagrammatic illustration of the formation of diimide from hydrazine and hydrogen peroxide; FIGURE 3 is a diagrammatic illustration of the saturation of olefins by diimide ; FIGURE 4 is a diagrammatic illustration of copper (II) absorbed on sulfonated polystyrene to form at cation exchange resin; FIGURE 5 is a diagrammatic illustration of an apparatus for saturating olefins and alkynes incorporating the method of the present invention; and FIGURE 6 is a partial sectional view comprising an enlargement of a portion of FIGURE 5.

DETAILED DESCRIPTION As is well known, olefins and alkynes are extremely unstable chemically and are capable of spontaneous polymerization. The presence of olefins and/or alkynes in hydrocarbon streams therefore results in the formation of sludge and other undesirable contaminants. Olefin and alkyne removal is therefore extremely useful in the treatment of fuels, lubricating oils, and the like, wherein the presence of sludge and similar contaminants is highly undesirable.

The present invention comprises a method of adding hydrogen across carbon- carbon double or triple bonds in a large variety of hydrocarbon streams. In this manner, hydrocarbons of the classes known as olefins or alkynes are transformed into hydrocarbons of the class known as alkanes. The process of adding hydrocarbons to olefins or alkynes is known as saturation or hydrogenation, and the present invention is successful in achieving total saturation of olefins and alkynes.

The process of the invention utilizes hydrazine and an oxidizer in slightly higher than stoichiometric amounts, and a metallic salt in catalytic quantities. Additionally, the process employs a small amount of a selected surfactant to generate a weak water-in-oil emulsion. In the emulsion, the catalyst resides at the oil/water interface, and the reaction therefore takes place at the oil/water interface.

The present invention further consists of immobilizing the copper catalyst on a cation exchange resin. While several cation exchange resins are suitable, the preferred resin is a highly cross-linked polymeric resin that has been derivatized to include a large

number of sulfonic acid sites such as poly (styrene-divinylbenzon) resin. The high cross-linking of the resin serves to prevent the resin from swelling in the presence of the emulsion. The capacity of the resin, that is the number of sulfonic acid exchange sites, may be varied to ensure proper wetting by the emulsion. Likewise, the strength of the emulsion may be varied so as to complement the resin capacity to ensure proper wetting.

While the resin may be simply suspended in solution, the preferred embodiment of the invention uses a cation exchange resin packed into a column through which a preformed emulsion is pumped. The preformed emulsion consists of the organic medium containing the unsaturated species, water, hydrazine and an inexpensive surfactant, preferably an anionic surfactant.

Another advantage of the present invention over that of the prior art is the ability of the resin to contain a relatively large amount of the copper catalyst. Larger amounts of the copper catalyst result in a very short reaction time without suffering the diimide- diimide reaction problem previously described.

Air or another oxidizing reagent, such as hydrogen peroxide, may be added to the emulsion. The oxidizing reagent serves to continuously regenerate the copper (II) catalyst, which is reduced to copper (I) upon the formation of diimide.

Yet another advantage of the invention results from use of the preferred embodiment of the invention wherein the reaction takes place in a column packed with the ion exchange resin. In accordance with the preferred embodiment of the invention, the resin is in the form of beads, ranging in size rom 5 to 100 microns or greater, which

serves to generate highly turbulent flow in the delivered emulsion. The turbulent flow allows the superior contact between the generated diimide and the species to be saturated, resulting in even faster reaction times. Additionally, the turbulent flow reduces the required amount of surfactant, leading to an emulsion that is easily broken in a clarifier that receives the emulsion following its residence in the packed column.

After clarification, the aqueous phase of the broken emulsion is recycled for use with additional organic material contaminated by unsaturated species, while the organic phase of the broken emulsion can be processed further, for example by distillation or extraction.

Examples of catalysts which may be utilized in the practice of the invention include all salts with copper, particularly including copper sulfate and copper chromate, and salts of iron, ruthenium, osmium, cobalt, and nickel. Examples of oxidizers which may be utilized in the practice of the invention include hydrogen peroxide, aqueous hydrogen peroxide in any concentration, organic peroxides including t-butyl hydroperoxide and peroxybenzoic acid, oxygen, and air.

Examples of surfactants that may be utilized in the practice of the invention include sodium dodecyl sulfate (SDS), sodium stearate, potassium stearate, lauroyl ethylenediaminetriacetic acid, salts of ethylenediaminetriacetic acid, all other anionic surfactants, cetyltrimethylammonium chloride, all other cationic surfactants, all zwitterionic surfactants including sulfobetaines. Surfactant systems composed of mixtures of two or more surfactants may also be used.

The optimum concentration range for a copper salt catalyst is 0.1-5.0 ppm (w/w) where a non-chelating surfactant such as sodium dodecyl sulfate, sodium stearate, or potassium stearate is employed. Where a chelating surfactant such as lauroyl ethylenediaminetriacetic acid is employed, the optimum catalyst concentration is in the range of 10-100 ppm. Concentrations as low as 0.001 ppm and as high as 1000 ppm maybeuseful, depending onthe requirements of particular applications of the invention.

In applications of the invention where a cation exchange resin is employed, the catalyst concentration is substantially equal to the capacity of the resin.

Concentrations of emulsions are optimal for oil : water weight ratios in the range 10: 90 to 90: 10. However, ratios as low as 1: 99 and as high as 99: 1 may be used in particular applications of the invention. The weight percent of surfactant is optimal in the range 0.01-5.0. However, concentrations of surfactant as high as 20 weight percent or as low as 0.0001 weight percent may be used depending upon the requirements of particular applications of the invention.

The amount of hydrazine used is determined by the amount of olefin to be saturated. Mole ratios (hydrazine: olefin) in the range 1.5: 1.0 to 10.0: 1.0 are optimal, however ratios as low as 1.0: 1.0 and as high as 1000: 1.0 may be used, again depending on the requirements of particular applications of the invention. The amount of oxidizer used is determined by the amount of hydrazine used. Mole ratios (oxidizer: hydrazine) in the range 1.0: 1.0 to 2.0: 1.0 are optimal, but higher ratios may also be used.

A more complete understanding of the invention may be had by reference to the drawings. Figure 1 illustrates the formation of diimide from hydrazine and air for oxygen. Figure 2 illustrates the formation of diimide from hydrazine and hydrogen peroxide. Figure 3 illustrates the saturation of olefins by diimide. Figure 4 illustrates the key to the present invention which is the absorption of copper (II) ions on a sulfonated polymer, such as polystyrene to form a cation exchange resin.

Referring to Figure 5, a system for recovering aged fuels 10 comprising a preferred embodiment of the invention is shown. Aged fuel from a source 12 is directed through a pump 14 and a heater 16 to a first static mixer 18. A surfactant is directed from a source 22 through a pump 24 to the static mixer 18 wherein it is thoroughly mixed with the aged fuel.

Hydrazine is directed from a source 28 through a pump 30 to a second static mixer 32. The fuel/surfactant mixture comprising the output from the first static mixer 18 is also directed to the second static mixer 32 wherein the hydrazine is thoroughly mixed into the fuel/surfactant mixture.

An oxidizer such as hydrogen peroxide, an organic peroxide, oxygen, or air is directed from a source 36 through a pump 38 to a third static mixer 40. The fuel/surfactant/hydrazine mixture comprising the output of the second static mixer 32 is also directed to the third static mixer 40 wherein the oxidizer is thoroughly mixed into the fuel/surfactant/hydrazine mixture.

In lieu of the oxidizer source 36, the pump 38, and the atic mixer 40, the emulsion from the second static mixer 32 may be directed through a micronizer 44 which entrains sub-micron size bubbles of a gaseous oxidizer received from a source 45 into the emulsion. The micronizer 44 may be similar to that disclosed in U. S. patent number 5,954,925. Other commercially availablc micronizers may also be used in the practice of this invention.

Either the emulsion from the third static mixer 40 having the oxidizer from the source 36 mixed therein or the emulsion from the micronizer 44 having sub-micron size oxidizer bubbles entrained therein is directed through a column 46 which is packed with an ion exchange resin including a catalyst. For example, the resin may be copper (II) absorbed on polystyrene. Other catalysts and other polymers may be used in the practice of the invention depending upon the requirements of particular applications of the invention. The ion exchange resin is initially charged and is recharge as necessary by directing a catalyst solution from a source 46 through a pump 48 through the polymeric material within the column 46.

The column 46 is further illustrated in Figure 6. The ion exchange resin is preferably in the form of beads 49. The beads 49 preferably have an average diameter of between about 5 microns and about 100 microns or larger.

Referring momentarily to Figures 1, 2, and 3, the foregoing steps of the method of the invention results the formation of diimide, which in tum saturates the olefins and

alkynes-ontained in the liquid hydrocarbon. The oxidizer in the emulsion regenerates the copper (II) catalyst which is reduced to copper (I) upon the formation of the diimide.

Referring again to Figure 5, the fuel/surfactant/hydrazine/oxidizer mixture comprising the output of the column 46 is directed to a clarifier 50 wherein the fuel is separated from most of the water, the surfactant, residual hydrazine, and residual oxidizer agent. The fuel is directed through a pump 52 and a heater 54 to a flash drum 56 which removes any remaining water from the fuel through an outlet 58. From the flash drum 56 the dehydrated fuel is directed through a pump 62 and a heater 64 to an evaporation column 66 wherein the fuel is separated into still bottoms which are recovered through an outlet 68 and one or more fuel components which are recovered through outlets 70,72, etc. Part of the still bottoms are recirculated through a pump 74 and the heater 64 to the evaporation column 66 while the remainder of the still bottoms are recovered through an outlet 76 for utilization as an asphalt modifier, etc.

The non-fuel liquid that is removed from the clarifier 50 comprises a mixture of water, surfactant, residual hydrazine, and residual oxidizer. The non-fuel mixture is directed to a reverse osmosis unit 80. The surfactant, residual hydrazine, and residual oxidizer are directed through a recirculation loop 82 to the second static mixer 32, thereby substantially reducing the amount of surfactant, hydrazine, and oxidizer that is necessary in the operation of the system 10. Water is recovered from the reverse osmosis unit 80 through an outlet 84 and is suitable either for direct discharge or for further processing, for example, in a water treatment plant.

Depending upon the amount of fuel to be processed, the entire system'0 may be mounted on a truck, trailer, or similar vehicle for transportation from location to location. Transportability of the system 10 is highly advantageous in that aged fuels requiring processing are typically stored in finite supplies at multiple locations.

Although preferred embodiments of the invention have been described in the foregoing Detailed Description, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications, and substitutions of parts and elements without departing from the spirit of the invention.