CROSS-REFERENCE TO RELATED APPLICATIONS

The following patent application is cross-referenced and hereby incorporated by reference in its entirety: U.S. Patent Application No. 60/543,062 titled "EFFLUENT TREATMENT SYSTEM" filed February 9, 2004. This application claims the benefit of U.S. Provisional Application No. 60/630,017 filed November 22, 2004, which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION The present invention generally relates to a system and method for the recovery of an oleaginous material. The present invention more particularly relates to an oil recovery system and method. The present invention more particularly relates to recovering from gums and soapstocks components such as oil, free fatty acids and products of phospholipids hydrolysis.

BACKGROUND OF THE INVENTION

In the conventional oil degumming process, water or steam (e.g. 1% water for soybean oil) is added to hot crude oil (~70C). As a result, a gum layer is formed (e.g. after contact time of ~5min.) and separated, e.g. by centrifugation. The thus degummed oil still contains phosphatides named non-hydratable phosphatides (NHP). Those NHP are removed in the alkali refining operation and end up in the soapstock.

Soapstock is the product of fatty acids removal from oil by treatment with an alkaline solution. Soapstock is formed and removed by centrifugation. Typically, neutral oil (triglycerides) is entrained in the recovered soapstock. An alternative to the conventional alkali treatment is removal of fatty acids by distillation (physical refining).

The preferred conventional practice is to recover value from soapstock by acidulation to liberate free fatty acids. If allowed to settle, the acidified soapstock breaks into three layers. The bottom layer is an acidic aqueous solution, which can be pumped off. The top layer contains the desired fatty acids and neutral oil. The middle layer, which is an emulsified sludge material, semi-solid, contains primarily gums, water and a substantial amount of desired fatty acids and neutral oil (its oleaginous material concentration is about 12%). In commercial soapstock acidulation processes, the sludge material is commonly retained with the fatty material initially. The sludge material is subsequently removed from the fatty layer by settling.

Aqueous solution separated from soapstock contains about 2.5-15% dissolved solids. Those include sulfuric acid and sodium sulfate (in cases where a sodium base was used in the alkali treatment and sulfuric acid in acidulation), glycerol, inositol phosphate and carbohydrates.

Known systems and methods for recovering from gums and soapstocks components such as oil, free fatty acids and products of phospholipids hydrolysis have several disadvantages including the use of flammable solvents, high-cost equipments, large amounts of water to be evaporated, etc. Accordingly, there is a need for an oil recovery system and method that provides for the relatively efficient recovery from gums and soapstocks of components such as oil, free fatty acids and products of phospholipids hydrolysis, commonly referred to as oleaginous material. It would be advantageous to provide a system and method for the recovery of an oleaginous material filling any one or more of these needs or having other advantageous features.

SUMMARY OF THE INVENTION

The present invention is directed to a method for the recovery of an oleaginous material (e.g. oil) from a feed stream that includes the oleaginous material or a precursor thereof, at least one emulsifier other than a fatty-acid salt, and water. In one embodiment, the method includes the steps of treating the feed stream to reduce the emulsification capacity of the emulsifier and/or to increase its

hydrophilicity, and fractionating the treated feed stream into at least one aqueous phase and at least one lipophilic phase.

In another embodiment, the present invention is directed to a method for the recovery of an oleaginous material from a feed stream that includes a triglyceride, an emulsifier other than a fatty-acid salt, a fatty acid salt and water. In one instance, the method includes contacting the stream with an acidic material to form free fatty acid, reducing the emulsification capacity of the emulsifier, and fractionating the stream into at least one aqueous phase and at least one lipophilic phase containing free fatty acid and a triglyceride.

The present invention can also be directed to a method for the recovery of an oleaginous material from a feed stream comprising a triglyceride, an emulsifier other than a fatty-acid salt, a fatty acid salt and water, that includes the steps of contacting the feed stream with an acidic material to form free fatty acids, separating at least a fraction of the free fatty acids to form separated free fatty acid and a fatty-acid-depleted stream having the emulsifier, reducing the emulsification capacity of the emulsifier in the fatty-acid depleted stream, and fractionating the fatty-acid depleted stream into at least one aqueous phase and at least one lipophilic phase.

In yet another embodiment, the present invention is directed to a method for refining a crude oil stream that includes the steps of degumming the crude oil stream to form degummed oil and gums comprising an emulsifier, treating the emulsifier-comprising gums to reduce the emulsification capacity of the emulsifier and/or to increase the hydrophilicity of the emulsifier, and fractionating the treated gums into at least one aqueous phase and at least one lipophilic phase.

Alternatively, the present invention can be directed to a method for refining a crude oil stream that includes the steps of treating the stream with an alkali treatment to form alkali-refined oil and soapstock comprising an emulsifier other than a fatty acid, treating the soapstock to reduce the emulsification capacity of the emulsifier in the soapstock and/or to increase the hydrophilicity of the emulsifier, treating the soapstock by contacting with an acidic material to form free

fatty acid, and fractionating the treated soapstock into at least one aqueous phase and at least one lipophilic phase.

In another instance, the present invention is directed to a method for refining crude oil stream that includes the steps of degumming the crude oil to form degummed oil and gums comprising an emulsifier, treating the oil with an alkali treatment to form alkali refined oil, soapstock comprising an emulsifier other than a fatty acid salt and optionally also gums, contacting the soapstock with an acidic material to form free fatty acids, treating the soapstock and/or gums to reduce the emulsification capacity of the emulsifier and/or to increase the hydrophilicity of the emulsifier; and fractionating at least one of the gums and the soapstock into at least one aqueous phase and at least one lipophilic phase.

In still another embodiment, the present invention is directed to a method for refining a crude oil stream that includes the steps of degumming the crude oil to form degummed oil and gums comprising an emulsifier, treating the oil with an alkali to form alkali refined oil, soapstock comprising an emulsifier other than a fatty acid salt and optionally also gums, separating the gums and the soapstock to form a co-product phase comprising at least a fraction of the emulsifier, at least a fraction of the gums and at least a fraction of the soapstock, treating the co- product phase to reduce the emulsification capacity of the emulsifier present in the co-product phase and/or to increase the hydrophilicity of the emulsifier, and fractionating the co-product phase into at least one aqueous phase and at least one lipophilic phase.

DETAILED DESCRIPTION OF THE PREFERRED AND OTHER EXEMPLARY EMBODIMENTS A system and method for the recovery of an oleaginous material relates to the recovery of an oleaginous material from a feed stream containing the oleaginous material or a precursor thereof, an emulsifier other than a fatty-acid salt, and water.

According to a preferred embodiment, the process comprises the steps of: (a) treatment that reduces the emulsification capacity of the emulsifier, and/or

increases its hydrophilicity and (b) fractionating into at least one aqueous phase and at least one lipophilic phase.

Oleaginous materials to be recovered according to the process include fatty acids and oil (neutral oil, triglycerides) according to a preferred embodiment. Feed streams suitable for treatment may result from various sources, including byproducts of oil refining such as gums, containing hydrated phospholipids and oil, and soapstocks containing fatty acid salts and oil according to any preferred or alternative embodiments. Other fatty-acid-salt containing and/or gums containing feed streams are also suitable for treatment if containing at least one emulsifier that is not a fatty acid salt. According to a preferred embodiment, the feed stream contains a solvent, e.g. hexane.

According to a preferred embodiment, in cases where the feed stream contains fatty acid salts, the process comprises an additional step of acidulation by contacting with an acidic material with acidity similar to that of the fatty acids or stronger.

In a preferred embodiment, such feed stream is a soapstock formed in the process of alkali refining of crude oil, wherein fatty acids are removed from crude oil as their salt. The alkali treatment is conducted after degumming or simultaneously with it, according to a preferred embodiment. Typically those are salts of alkaline metals such as sodium or potassium, but could also be salts of other metals, such as alkaline earth metals, and also salts of ammonia and of organic bases. Fatty acid salts are emulsifiers. According to a preferred embodiment, the stream to be treated contains, in addition, at least one other emulsifier, such as phospholipid, phosphatidic acid, non-hydratable phosphatide, a product of their hydrolysis, mono- and di-glyceride, glycolipid, etc. In many cases, that other emulsifier also results from the crude oil. The stream may also contain other fatty material, e.g. oil entrained in soapstock.

Acidulation is done by contacting with an acidic material, which is of acid strength similar to that of fatty acids or stronger, i.e. materials with pKa < 7, more preferably <5. That acidic material is at least partially in its free acid form

according to a particularly preferred embodiment. Both mineral and organic acids are suitable. Acidic oxides, such as SO2, acidic anion exchanges and acidic zeolites are also suitable. According to a preferred embodiment, the amount of acid used is similar to that of fatty acid salt in the treated stream or greater.

According to another preferred embodiment, the feed stream to be treated is obtained in the process of crude oil degumming.

Such stream, referred to as gums or crude lecithin, contains phospholipids, water and optionally also oil (neutral oil, triglycerides). According to another preferred embodiment, the feed stream to be treated is obtained in a combined or sequential degumming and alkali treatment or is formed by combining gums and soapstock.

According to a preferred embodiment, the stream to be treated contains a solvent. According to another preferred embodiment, the feed stream is obtained in treating crude oil, which is formed by contacting an oilseed (e.g. soybean, canola, sunflower, corn) with an organic solvent (e.g. hexane) followed by removing partially or substantially completely the solvent (e.g. by distillation) to form crude oil. According to a preferred embodiment, at least a fraction (e.g. about 10% to about 100% by weight) of the solvent is present during the degumming and/or during the alkali treatment and/or during the reducing the emulsifying capacity and/or the increasing of the hydrophilicity of the emulsifier and/or contacting with an acidic compound and/or fractionating.

According to a preferred embodiment, reducing the emulsifying capacity of the emulsifier is facilitated by at least one of temperature, a chemical catalyst, an enzyme, an electrolyte, and combinations thereof. According to a preferred embodiment, the electrolyte comprises at least one of carboxylic acids, carboxylic acid salts, amino acid, amino acid salts, mineral salts, salts of potassium, salts of ammonium, salts of nitrate, salts of phosphate, and combinations thereof.

Various methods could be used for the chemical or enzymatic modification of the non-fatty acid-salt emulsifier, e.g. ones that chemically modify its hydrophobic

end, ones that chemically modify its hydrophilic end, ones that detach or replace a hydrophilic fraction of it and ones that detach or replace a hydrophobic fraction of it according to alternative embodiments. Typically, such emulsifier is an ester or an ether and such detachment could be achieved by hydrolysis. Alternatively, 5 replacement is conducted by trans-esterification. Optionally, the hydrolysis is conducted at elevated temperature, preferably higher than about 100C, more preferably between about 100C and about 400C, most preferably between about 16OC and about 300C. According to a preferred embodiment, the reaction is conducted under super-atmospheric pressure. A suitable catalyst could be used. o Such catalysts include a chemical one or a biological one, e.g. an enzyme such as phospholipase. Catalyzed hydrolysis processes may be conducted at temperatures lower than non-catalyzed hydrolysis processes, particularly if enzymatically catalyzed.

According to a preferred embodiment an enzyme is used to facilitate reducing the s emulsifying capacity of the emulsifier and/or to increase its hydrophilicity.

According to a preferred embodiment the used enzyme is suited or adjusted for operation in an organic medium. According to another preferred embodiment, the enzyme is immobilized on a solid carrier. According to a preferred embodiment, the treated feed stream is moving respectively to an immobilized enzyme.

o In cases of emulsifiers containing more than one ester or ether bond in the molecule, it may be sufficient to hydrolyze or trans-esterify only one of those in order to form a product that is oil soluble and a product that is water soluble. Thus, in those cases where the emulsifier is a phospholipid, hydrolysis of the ester function in position 1 or 2 forms a lysophospholipid, which is water soluble, and a 5 fatty acid that is oil soluble. On the other hand, hydrolysis of the ester bond between the glycerol and the phosphate or that between the phosphate and the bound alkanol (e.g. choline, ethanolamine, serine or inositol) forms a small hydrophilic hydrolysis product and a larger, oil soluble product, e.g. phosphatidic acid. In some other cases, hydrolysis or trans-esterification of more than one o bond is preferred. According to still another preferred embodiment, one of the bonds on an emulsifier is hydrolyzed and another one is trans-esterified.

In those cases where hydrolysis or trans-esterification is used for the chemical modification of the emulsifier, the reaction may be selective to the emulsifier or non-selective so that both the emulsifier and oil present in the treated stream are reacted. Selective hydrolysis is e.g. an enzymatically catalyzed one. In non- enzymatically catalyzed hydrolysis, lower hydrolysis temperatures prefer the hydrolysis of phospholipids over the hydrolysis of oil. In cases where selective non-enzymatic hydrolysis is desired, the reaction is preferably conducted at a temperature of below about 240C.

The reduction in the emulsifying capacity may facilitate fractionation and increase the recovery yield in that step. The fractionation step may be a gravimetric fractionation, e.g. settling or centrifugation. Other fractionation methods are suitable too, e.g. solvent extraction and distillation according to alternative embodiments.

The fractionation step forms an aqueous solution. In cases where an acidulation step was conducted, the aqueous phase contains, among other components, the salt of the base used in the alkaline refining step and the acid used in the acidulation step.

The fractionation step also forms a lipophilic phase. That phase contains free fatty acids liberated from the fatty acid salts and free fatty acids formed in the hydrolysis step. In case of selective hydrolysis, those are mainly fatty acids detached from the emulsifier, while in case of non-selective hydrolysis, fatty acids could result also from hydrolysis of triglycerides. In case of selective hydrolysis, the lipophilic phase may also contain oil. The fatty acids in the lipophilic phase could be used for various applications, such as in animal feed and for the production of fatty acids esters, e.g. methyl ester to be used as biodiesel. If the lipophilic phase contains high proportion of oil, it could be combined with the partially refined oil at a suitable step of the refining and increase thereby the oil recovery yield. Alternatively, the free fatty acids are separated from the oil in the lipophilic phase, e.g. by distillation, preferably to form a stream of free fatty acids

and a stream of concentrated oil. Such concentrated oil can be combined with crude or partially refined oil and increase thereby the oil recovery yield.

In some cases, there may be a preference for repeating a step of the process. That is particularly true for the fractionation step. A fractionation step may be required after the chemical modification or simultaneously with it.

In processes involving an acidulation step, the process may be conducted in various sequences and in some cases also simultaneously. There is also the option of adding other streams or reagents at various stages of the process according to an alternative embodiment. For example, the chemical modification is conducted first, followed by acidulation and fractionation. Alternatively, acidulation is conducted first, followed by the chemical modification and fractionation. Conducting acidulation simultaneously with chemical modification is also an option. Still another option is acidulation first, followed by separation of the aqueous phase, and then chemical modification and fractionation. Chemical modification could also be conducted on the sludge formed by acidulation followed by separation of both an aqueous phase and a lipophilic phase. Gums, e.g. those formed in crude oil degumming, could be added at any of the steps, preferably prior to the chemical modification one.

According to a preferred embodiment, compounds present in the treated stream or formed during hydrolysis - e.g. choline, serine, glycerol or lysolecithin - are separated and optionally purified. Such separation is preferably conducted in cases where an aqueous phase is separated after acidulation and prior to the chemical modification or after it.

According to another preferred embodiment, the chemical modification for reducing the emulsifier capacity is conducted by a reaction with a hydrophilic part of the emulsifier. An example for such reaction is esterification of the hydroxyl group in diglyceride to form a triglyceride, preferably with a fatty acid present in the treated stream. Alternatively, the hydrophilic part is replaced by a lipophilic one, as in the case of trans-esterification wherein fatty acid replaces the phosphate ester on phospholipids.

While the preferred and other exemplary embodiments described in this disclosure are presently preferred, it should be understood that these embodiments are offered by way of example only. The invention is not limited to a particular embodiment, but extends to various modifications, combinations, and permutations.