Phosphorus Removal Process

Abstract

The present invention relates to processes for refining oils. In particular, the present invention relates to methods for refining oils of biological origin, such as vegetable oils.

Description

Technical Field

[0001] The present invention relates to processes for refining oils. In particular, the present invention relates to methods for refining oils of biological origin, such as vegetable oils. Background Art

[0002] Oils from biological sources, such as vegetable and animal oils, are used in many applications. Vegetable oils can be used in cooking foods and as food additives added to products consumed by humans and animals. Vegetable oils can also be hydrogenated or partially hydrogenated, and these hydrogenated vegetable oils can also be used as food additives. Vegetable oils also have industrial uses in products such as soaps, skin care products, candles, perfumes and other personal care and cosmetics, paints, wood processing products, etc. Vegetable oils are also increasingly used in the production of biodiesel fuel. In this application, the triglyceride component of the vegetable oil undergoes a transesterification reaction to produce monoalkyl esters of fatty acids, which form the main component of biodiesel. The use of vegetable oils as an alternative energy source is increasing, and the supply of biodiesel is also increasing worldwide.

[0003] Vegetable oil can also be recycled after use. In particular, vegetable oil can be recovered from restaurants, snack food plants, potato processing plants, and industrial deep fryers. The recovered oil can be used for applications such as direct fuel, conversion to biodiesel, soap, animal feed, pet food, detergents, and cosmetics.

[0004] Vegetable oils are extracted from many different types of plants. Examples of plants from which vegetable oils are extracted include palm, soybean, rapeseed, sunflower, peanut, cottonseed, palm kernel, coconut, olive oil, safflower, rapeseed and cottonseed, corn oil, peanut, rice bran. Of these vegetable oils, palm oil, soybean oil, rapeseed oil, and sunflower oil have the highest production in the world.

[0005] Vegetable oil production involves extracting vegetable oils from plant components, such as seeds. This is usually done through mechanical extraction, which is performed in an oil press, or using chemical solvents. Mechanical extraction, which is usually performed in an oil press, involves crushing or squeezing the plant components to release the vegetable oil. Methods of mechanical extraction include screw press pressing, spiral pressing, plunger pressing, and using a powered pestle and mortar. Chemical solvent extraction can also be used to extract vegetable oils from plants. This generally gives higher yields and is faster and less expensive than mechanical extraction. However, mechanical extraction is often preferred over chemical extraction because it is often considered a more natural and healthier way to extract vegetable oils from plants. Many modern vegetable oil extraction methods use both mechanical extraction and solvent extraction. One common method uses a screw to pulverize the feedstock in a continuous process, and then extracts the oil from the filter cake using a centrifuge or a solvent, such as hexane.

[0006] Once vegetable oils are extracted, they are typically refined to remove various impurities and unwanted components before use. The primary components of vegetable oils are triglyceride molecules. Impurities include organophosphorus compounds such as phospholipids, mucilage substances, waxes, free fatty acids, polysaccharides and oligosaccharides, proteins, chloropropanols, glycidol, phosphorus-containing compounds, and metals. Many of the phosphorus-containing compounds and metals are present because they are protein components that are extracted from the plant into the vegetable oil during the extraction process. The glyceride oil refining process may also extract lipids, pigments, volatile odor compounds, and other components that can negatively affect the stability of the oil or present potential toxicity issues.

[0007] Vegetable oil refining is carried out through multiple processes and is performed in a vegetable oil refinery. The refining of vegetable oil is very important for removing gums, waxes, phospholipids, free fatty acids (FFA) and other impurities in the oil, as well as removing pigments and removing bad odors from the oil by removing odorous substances. Typically, the first process performed on vegetable oils in an oil refinery is the degumming process. This process typically involves hydrating the vegetable oil with water or steam or adding acid to the oil. This process removes organic phosphorus compounds, such as phospholipids, and other mucous substances that form gums from the oil. If these materials are not removed, gum-like materials may form in the vegetable oil when stored.

[0008] After degumming, a deacidification process is usually carried out to remove free fatty acids from the vegetable oil. If free fatty acids remain in the vegetable oil, they may give the vegetable oil a rancid or soapy taste and cause other problems. Conventional methods for removing free fatty acids include treating the vegetable oil with an alkaline aqueous solution, by treating with steam at a temperature of about 220°C, esterification with glycerol to form triglycerides, and using solvent extraction or absorbents. Once the free fatty acids are removed from the vegetable oil, further processing steps include bleaching, deodorization, dewaxing, decolorization and winterization of the vegetable oil.

[0009] A method known in the art for removing free fatty acids from vegetable oils is to extract the free fatty acids using aqueous organic amines. An aqueous solution of an organic amine such as dimethylethanolamine is added to the vegetable oil. In this process, the free fatty acids are transferred from the triglyceride phase of the vegetable oil to the aqueous organic amine phase, which can then be separated from the vegetable oil.

[0010] US6579996 discloses a method for removing free fatty acids from fats or oils of biological origin by extracting the free fatty acids using a mixture of a basic organic nitrogen compound and water as an extraction medium.

[0011] US 1,885,859 discloses a process for purifying oils, fats and waxes of the ester type by contacting the material to be treated with an alkanolamine.

[0012] US2164012 discloses a process for refining fatty substances using a nitrogen-containing amine extractant, which comprises washing the raffinate obtained from the main extraction with water to remove free extractant and then washing the raffinate with a dilute aqueous acid solution to remove soap from the fatty substance.

[0013] The inventors of the present invention have recognized that it would be beneficial to provide a method for simultaneously removing free fatty acids and other impurities from vegetable oils. For example, it would be advantageous to provide a method for removing phosphorus and phosphorus-containing compounds from vegetable oils while reducing the free fatty acid content. Since phosphorus-containing compounds are typically removed from vegetable oils by a degumming process, removing phosphorus and phosphorus-containing compounds in the same step can reduce or even eliminate the need for a degumming process, thereby simplifying the vegetable oil refining process. Summary of the invention

[0014] The present invention is based on the surprising discovery that organic amines can remove other impurities from glyceride oils (e.g., vegetable oils) in addition to free fatty acids. Surprisingly, it has been found that phosphorus and phosphorus-containing compounds present in glyceride oils (e.g., vegetable oils) can be removed by contacting the glyceride oils with organic amines.

[0015] One aspect of the present invention provides the use of an organic amine for removing phosphorus and / or phosphorus-containing compounds from a glyceride oil comprising phosphorus and / or phosphorus-containing compounds by contacting the oil with the organic amine, wherein the organic amine is selected from:

[0016] N(R a )(R b )(R c ),

[0017] Where: R a , R b and R c Each independently selected from C 1 To C 8 A straight or branched alkyl or C 3 To C 6 A cycloalkyl group; or R a , R b and R c Any two of them combine to form an alkylene chain -(CH 2 )q-, wherein q is 3 to 6; and wherein the alkyl or cycloalkyl group may be optionally substituted with 1 to 3 groups selected from the following: C 1 To C 4 Alkoxy, C 2 To C 8 Alkoxyalkoxy, C 3 To C 6 Cycloalkyl, -OH, -NH 2 , -SH, -CO2 (C 1 To C 6 )alkyl and -OC(O)(C 1 To C 6 ) alkyl; or R a is hydrogen, R b and R c As mentioned before.

[0018] Another aspect of the present invention provides a method for removing phosphorus and / or phosphorus-containing compounds from glyceride oil, the method comprising the steps of:

[0019] (i) contacting a glyceride oil containing phosphorus and / or phosphorus-containing compounds with an organic amine and water to form a treated glyceride oil and water phase; wherein the water is added in an amount of 5% v / v to 40% v / v relative to the organic amine, and the amount of the organic amine is 1 wt.% to 75 wt.% relative to the glyceride oil; wherein phosphorus is present in the glyceride oil in an amount of 0.25 ppm to 10,000 ppm; and the organic amine is selected from:

[0020] N(R a )(R b )(R c ),

[0021] Where: R a , R b and R c Each independently selected from C 1 To C 8 A straight or branched alkyl or C 3 To C 6 A cycloalkyl group; or R a , R b and R c Any two of them combine to form an alkylene chain -(CH 2 )q-, wherein q is 3 to 6; and wherein the alkyl or cycloalkyl group may be optionally substituted with 1 to 3 groups selected from the following: C 1 To C 4 Alkoxy, C 2 To C 8 Alkoxyalkoxy, C 3 To C 6 Cycloalkyl, -OH, -NH 2 , -SH, -CO 2 (C 1 To C 6 )alkyl and -OC(O)(C 1 To C 6 ) alkyl; or R a is hydrogen, R b and R c As previously mentioned; and

[0022] (ii) after the glyceride oil is contacted with the organic amine and water, separating the treated glyceride oil from the aqueous phase; wherein the treated glyceride oil has a reduced concentration of phosphorus and / or phosphorus-containing substances compared to the glyceride oil contacted in step (i). DETAILED DESCRIPTION

[0023] A first aspect of the present invention provides the use of an organic amine for removing phosphorus and / or phosphorus-containing compounds from a glyceride oil comprising phosphorus and / or phosphorus-containing compounds by contacting the oil with the organic amine, wherein the organic amine is selected from:

[0024] N(R a )(R b )(R c ),

[0025] Where: R a , R b and R c Each independently selected from C 1 To C 8 A straight or branched alkyl or C 3 To C 6 A cycloalkyl group; or R a , R b and R c Any two of them combine to form an alkylene chain -(CH 2 )q-, wherein q is 3 to 6; and wherein the alkyl or cycloalkyl group may be optionally substituted with 1 to 3 groups selected from the following: C 1 To C 4 Alkoxy, C 2 To C 8 Alkoxyalkoxy, C 3 To C 6 Cycloalkyl, -OH, -NH 2 , -SH, -CO 2 (C 1 To C 6 )alkyl and -OC(O)(C 1 To C 6 ) alkyl; or R a is hydrogen, R b and R c As mentioned before.

[0026] The method of treating the phosphorus-containing glyceride oil by contacting the phosphorus-containing glyceride oil with an organic amine to reduce the phosphorus concentration can be suitably applied to crude phosphorus-containing glyceride oil that has not undergone any prior refining steps. Alternatively, the above method can be applied to phosphorus-containing glyceride oil that has undergone one or more additional refining steps before being treated with an organic amine.

[0027] Therefore, the organic amine treatment can be integrated into several stages of the glyceride oil refining process. For example, the treatment can be implemented at the stage at the beginning of the refining process. Alternatively, the treatment can be implemented at the end of the refining process. This flexibility makes the organic amine treatment according to the present invention particularly attractive for integration into pre-existing refining processes and systems.

[0028] The term "crude / rough" used herein with respect to glyceride oils is intended to mean a glyceride oil that has not undergone a refining step after oil extraction. For example, a crude glyceride oil will not be degummed, deacidified, winterized, bleached, decolorized or deodorized. The term "refined / refined" used herein with respect to glyceride oils is intended to mean a glyceride oil that has undergone one or more refining steps, such as degumming, deacidification, winterization, bleaching, decolorization and / or deodorization.

[0029] Use according to the present invention includes contacting phosphorus-containing glyceride oil with an organic amine to reduce the concentration of phosphorus in the glyceride oil. The organic amine can be added to the glyceride oil in any suitable amount sufficient to remove phosphorus and phosphorus-containing compounds from the glyceride oil. Typically, the organic amine is added to the glyceride oil in an amount of 1wt.% to 80wt.% relative to the glyceride oil. Preferably, the organic amine is added in an amount of 1wt.% to 40wt.% relative to the glyceride oil, more preferably 1wt.% to 20wt.%, most preferably 2wt.% to 8wt.%. For example, the organic amine is added in an amount of 4wt.% to 6wt.% relative to the glyceride oil, for example 5wt.%.

[0030] The use according to the present invention preferably comprises adding water to the glyceride oil and the organic amine. The water can be any kind of water. For example, water of different purities can be used. A purer form of water, such as distilled water, can be used, but water with various impurities (such as salts dissolved therein) can also be used. Water can be present in any suitable amount sufficient to remove phosphorus and phosphorus-containing compounds from the glyceride oil. For example, water can be present in an amount of 1% v / v to 80% v / v relative to the organic amine. Typically, water is present in an amount of 15% v / v to 40% v / v relative to the organic amine. Preferably, water is present in an amount of 25% v / v to 35% v / v relative to the organic amine, for example 30% v / v.

[0031] Alternatively, different solvents or solvent mixtures can be used, provided that the solvent can coexist with the glyceride oil and the organic amine. Polar solvents are preferred alternative solvents. For example, alcohols or mixtures of water and alcohols can be used.

[0032] Typically, the organic amine used is a compound having the formula:

[0033] N(R a )(R b )(R c ),

[0034] Where: R a , R b and R c Each independently selected from C 1 To C 8 wherein the alkyl group may be unsubstituted or substituted by 1 to 3 groups selected from the following: 1 To C 4 Alkoxy, C 2 To C 8 Alkoxyalkoxy, C 3 To C 6 Cycloalkyl, -OH, -NH 2 , -SH, -CO 2 (C 1 To C 6 )alkyl and -OC(O)(C 1 To C 6 ) alkyl, for example 1 to 3 -OH or -NH 2 group; or R a is hydrogen, R b and R c As mentioned before.

[0035] Preferably, the organic amine is a compound having the formula:

[0036] N(R a )(R b )(R c ),

[0037] Where: R a , R b and R c Each independently selected from C 1 To C 4 A straight chain or branched alkyl group, wherein R a , R b and R c At least one of them is substituted with a single -OH group.

[0038] More preferably, the organic amine is a tertiary amine comprising three alkyl chains bonded to the nitrogen atom, wherein one of the alkyl chains is substituted by an OH group.

[0039] Most preferably, the organic amine is dimethylethanolamine, a compound having the formula:

[0040]

[0041] Dimethylethanolamine is highly preferred because it is approved in many countries for use as an additive or reagent in food processing. This is particularly advantageous for applications using glyceride oils in food or as edible oils.

[0042] Organic amines can be used to reduce the concentration of any form of phosphorus present in phosphorus-containing glyceride oils. For example, organic amines can be used to reduce the concentration of elemental phosphorus or phosphorus-containing compounds. Preferably, phosphorus is present in the glyceride oil in the form of phosphorus-containing compounds. Phosphorus-containing compounds are common components of glyceride oils (e.g., vegetable oils) because phosphorus is typically present in many biomolecules in the plants from which the vegetable oils are extracted. When vegetable oils are extracted from plants or seeds in an oil press, many of these biomolecules remain in the vegetable oils. Even during the processing of vegetable oils, when complex biomolecules containing phosphorus are broken down, phosphorus may also remain in the vegetable oil in one form or another, for example in the form of phosphorus-containing compounds.

[0043] Phosphorus-containing compounds that may be present in glyceride oils and whose concentration in the oil may be reduced by use according to the invention include, but are not limited to, phospholipids, phospholipids, or any combination thereof.

[0044] There are many reasons why it is desirable to remove phosphorus-containing compounds from oils. For example, phosphorus-containing compounds (e.g., phospholipids) may contribute to the formation of gums in vegetable oils. There are many reasons why gums may be removed. Due to their emulsifying properties, gums may cause high refining losses. Gum may also decompose, causing the oil to turn black due to their thermal instability.

[0045] Prior to reducing the concentration of phosphorus or phosphorus-containing compounds present in the glyceride oil according to the present invention, the phosphorus or phosphorus-containing compounds present in the glyceride oil are typically present in an amount (phosphorus) of 0.25 ppm to 50,000 ppm, preferably 0.25 ppm to 10,000 ppm. In some cases, phosphorus is present in the glyceride oil in an amount of 1 ppm to 100 ppm, preferably 10 ppm to 50 ppm, more preferably 10 ppm to 20 ppm.

[0046] The phosphorus content of the glyceride oil can be measured by any suitable technique known in the art. For example, ICP-OES analysis can be used to determine the phosphorus concentration in the glyceride oil.

[0047] The use according to the present invention comprises contacting the phosphorus-containing glyceride oil with an organic amine and water (preferably). The contact is carried out at a temperature below the boiling point of the organic amine. The contact is carried out at a temperature below the boiling point of the organic amine. Typically, the contact is carried out at a temperature below 130°C, or below 80°C, preferably 25°C to 70°C, more preferably 35°C to 65°C, most preferably 45°C to 55°C, for example 50°C. It should be understood that when the glyceride oil is semi-solid at room temperature, a higher temperature is preferred so that the glyceride oil is in liquid form to contact with the liquid organic amine. Suitably, the contacting step is carried out at 0.1MPa absolute pressure to 10MPa absolute pressure (1bar absolute pressure to 100bar absolute pressure).

[0048] The contacting of the phosphorus-containing glyceride oil, the organic amine and water (preferred) typically comprises stirring the phosphorus-containing glyceride oil, the organic amine and water (if present) for a suitable period of time. Typically, stirring is performed for 1 minute to 1 hour, preferably 5 minutes to 30 minutes.

[0049] The contacting is preferably carried out in a mixer, such as a shear mixer. Alternatively, the contacting is carried out using an ultrasonic stirrer, an electromagnetic stirrer or by bubbling an inert gas through the mixture. Preferably, the mixture of the organic amine, glyceride oil and water (preferably) is stirred at a speed of 500 to 5000 rpm, preferably at a speed of 3500 to 4500 rpm, for example 4000 ppm.

[0050] Typically, after the step of contacting and stirring the glyceride oil, the organic amine and water (if present), the mixture is left to stand so that the oil phase is separated from the non-organic phase. The non-organic phase comprises the organic amine and water (preferred). The oil phase comprises the treated glyceride oil, which has a reduced concentration of phosphorus compared to the phosphorus-containing glyceride oil before treatment. Typically, the mixture is left to stand for several hours to allow the two phases to separate, and preferably the mixture is left to stand overnight.

[0051] Any suitable method can be used to separate the treated glyceride oil phase and the non-organic phase. For example, gravity separation (for example, in a sedimentation unit) can be carried out. In this method, the treated glyceride oil is usually the upper phase, and the organic amine and water (if present) form the lower phase. It is also possible to use, for example, a decanter, a hydrocyclone, an electrostatic coalescer, a centrifuge or a membrane filter press to achieve separation. The contact and separation steps can be repeated multiple times, for example 2 to 4 times. Preferably, separation is carried out by centrifugation.

[0052] The contact and separation steps can also be carried out together in a countercurrent reaction tower. The glyceride oil (hereinafter referred to as the "oil feed stream") is usually introduced at the bottom or near the bottom of the countercurrent reaction tower, while the organic amine (hereinafter referred to as the "organic amine feed stream") is introduced at the top or near the top of the countercurrent reaction tower. The treated oil phase (hereinafter referred to as the "product oil stream") is discharged from the top of the tower, and the phase containing the organic amine and the solvent (if present) (hereinafter referred to as the "secondary stream") is discharged from its bottom or near the bottom. Preferably, the countercurrent reaction tower has a pool area for collecting secondary streams. Preferably, the oil feed stream is introduced into the countercurrent reaction tower just above the pool area. More than one countercurrent reaction tower can be used, for example 2 to 6, preferably 2 to 3 towers arranged in series. Preferably, the countercurrent reaction tower is filled with structured packing, such as glass Raschig rings, so as to increase the flow path of the oil and organic amine through the tower. Alternatively, the countercurrent reaction tower may comprise multiple plates.

[0053] In some cases, the contacting and separation steps are carried out together in a centrifugal contact separator, for example, the centrifugal contact separators described in US 4,959,158, US 5,571,070, US 5,591,340, US 5,762,800, WO 99 / 12650 and WO 00 / 29120. Suitable centrifugal contact separators include those provided by Costner Industries Nevada, Inc. Glyceride oil and organic amine can be introduced into the annular mixing zone of the centrifugal contact separator. Preferably, glyceride oil and organic amine are introduced into the annular mixing zone as separate feed streams. Glyceride oil and organic amine are mixed rapidly in the annular mixing zone. The resulting mixture is then conveyed to a separation zone, where centrifugal force is applied to the mixture to completely separate the oil phase and the secondary phase.

[0054] Preferably, a plurality of centrifugal contact separators are used in series, preferably 2 to 6, for example 2 to 3, are used in series. Preferably, the oil feed stream is introduced into the first centrifugal contact separator in the series, while the organic amine feed stream is introduced into the last centrifugal contact separator in the series, so that the oil with a gradually decreasing content of, for example, free fatty acids (FFA), phosphorus or phosphorus-containing compounds passes from the first centrifugal contact separator in the series to the last centrifugal contact separator, while the organic amine stream with a gradually increasing content of, for example, FFA, phosphorus or phosphorus-containing compounds passes from the last centrifugal contact separator in the series to the first centrifugal contact separator. Thus, the phase containing organic amine, phosphorus, phosphorus-containing compounds and FFA is removed from the first centrifugal contact separator, and the treated oil phase is removed from the last centrifugal contact separator in the series.

[0055] The treated glyceride oil may also be passed through a coalescing filter for coalescing fine droplets of the non-oil phase liquid, thereby creating a continuous phase and promoting phase separation. Preferably, when the organic amine used for contacting is used in combination with a solvent, the coalescing filter is wetted with the same solvent to improve filtration.

[0056] After the organic amine, glyceride oil and water (preferably) have been contacted and separated, the treated glyceride oil is separated from the non-organic phase. Compared with before contacting with the organic amine, the phosphorus concentration of the treated glyceride oil is lower. Typically, the phosphorus concentration of the treated glyceride oil is lower than 90% of the phosphorus-containing glyceride oil before treatment. For example, the phosphorus content of the treated glyceride oil can be lower than 80%, 70%, 60%, 50%, 40%, 30%, 20% or 10% of the phosphorus-containing glyceride oil concentration before treatment. Preferably, the phosphorus concentration of the treated glyceride oil is less than 10% of the phosphorus-containing glyceride oil before treatment, and most preferably less than 5%.

[0057] The treated glyceride oil can be further treated to remove residual organic amines that may be present in the treated glyceride oil. For example, the treated glyceride oil can be washed with a small amount of water (e.g., 100 ml) to reduce the concentration of any residual organic amines present in the treated glyceride oil.

[0058] The treated glyceride oil can then be dried to further reduce the concentration of the residual organic amines present in the treated glyceride oil. For example, the organic amines can be removed from the treated glyceride oil by vacuum drying. Alternatively, the organic amines can be removed from the treated glyceride oil by vacuum distillation.

[0059] The use according to the present invention may comprise contacting the organic amine with any type of phosphorus-containing glyceride oil. The phosphorus-containing glyceride oil may comprise an animal oil or a vegetable oil. Preferably, the phosphorus-containing oil comprises a vegetable oil.

[0060] The term "glyceride oil" used herein refers to an oil or fat comprising triglyceride as its main component. For example, the triglyceride component can be at least 50wt.% of a glyceride oil. Glyceride oil can also include monoglyceride and / or diglyceride. Preferably, glyceride oil is obtained at least in part from a natural source (for example, plant, animal or fish / crustacean source) and is also preferably edible. Glyceride oil includes vegetable oil, marine oil and animal oil / fat, and they typically also include the phospholipid component of crude product form. Typically, phosphorus-containing glyceride oil includes vegetable oil or animal oil that is liquid at room temperature. However, phosphorus-containing glyceride oil can also include vegetable oil or animal oil that is solid at room temperature. In this case, the contact of glyceride oil with organic amine can be carried out at a temperature higher than room temperature and higher than the glyceride oil fusing point.

[0061] Vegetable oils include all vegetable oils, nut oils and seed oils. Examples of suitable vegetable oils that can be used in the present invention include: acai oil, almond oil, beech oil, cashew oil, coconut oil, rapeseed oil, corn oil, cottonseed oil, grapefruit seed oil, grape seed oil, peanut oil, hazelnut oil, lemon oil, macadamia oil, mustard oil, olive oil, orange oil, palm oil, palm kernel oil, wild bean oil, pecan oil, pine nut oil, pistachio oil, rapeseed oil, rice bran oil, safflower oil, sesame oil, soybean oil, sunflower seed oil, walnut oil and wheat germ oil.

[0062] Suitable marine oils include oils derived from the tissue of oily fish or crustaceans (eg krill).Examples of suitable animal oils / fats include pig fat (lard), duck fat, goose fat, tallow and butter.

[0063] Preferably, the glyceride oil comprises a vegetable oil. Preferred vegetable oils include coconut oil, corn oil, cottonseed oil, peanut oil, olive oil, palm oil, rapeseed oil, rice bran oil, safflower oil, soybean oil, sunflower oil or mixtures thereof.

[0064] The term "soybean oil" used herein includes the oil extracted from the seed of soybean (Glycine max). The term "rapeseed oil" used herein is synonymous with rapeseed oil, and refers to the oil derived from rapeseed plant species, such as rapeseed (Brassicanapus L.) or rapeseed (Brassica rapa subsp.oleifera, syn.B.campestris L.). The term "palm oil" used herein includes the oil derived at least in part from the oil palm tree (a part of the Arecaceae family), and includes oil palm species Elaeisguineensis (African oil palm) and oil palm species Elaeis oleifera (U.S. oil palm), or its hybrid species. Therefore, the palm oil mentioned herein also includes palm kernel oil and fractionated palm oil, such as palm oil stearin or palm oil olein fractions.

[0065] In examples of the present disclosure, the phosphorus-containing glyceride oil comprises a cooking oil, such as a vegetable cooking oil. In some cases, the phosphorus-containing glyceride oil comprises a used oil. In some cases, the phosphorus-containing glyceride oil comprises a used vegetable oil, preferably a used vegetable cooking oil.

[0066] Purpose according to the present invention can also include the free fatty acid (FFA) content that reduces phosphorus-containing glyceride oil.Glyceride oil generally comprises free fatty acid molecules, and in its refining process, expects to remove from glyceride oil.The FFA that may exist in glyceride oil comprises monounsaturated FFA, polyunsaturated FFA and saturated FFA.The example of unsaturated FFA comprises: myristoleic acid, palmitoleic acid, 6 cis-hexadecenoic acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, trans-linoleic acid, α-linolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid and docosahexaenoic acid.The example of saturated FFA comprises: caprylic acid, capric acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, heptadecanoic acid, stearic acid, nonadecanoic acid, arachidic acid, heneicosanoic acid, behenic acid, lignoceric acid and cerotic acid.

[0067] In an example of the present invention, the free fatty acid is present in the phosphorus-containing glyceride oil in an amount of 1 wt.% to 50 wt.%, preferably 1 wt.% to 30 wt.%, more preferably 5 wt.% to 25 wt.%, and most preferably 5 wt.% to 20 wt.%.

[0068] After treatment with organic amines according to the use of the present invention, the free fatty acid content of the glyceride oil is generally reduced to 0.1 wt.% to 10 wt.%, preferably 0.1 wt.% to 5 wt.%, more preferably 0.1 wt.% to 1 wt.%, most preferably 0.25 wt.% to 1 wt.%.

[0069] The fatty acid content of glyceride oils can be determined using standard testing procedures in the art, such as ASTM D5555.

[0070] The use according to the invention may comprise further processing of the treated glyceride oil. The treated glyceride oil is usually further processed as part of a typical glyceride oil refining process.

[0071] The skilled artisan is aware of the different refining steps commonly used in edible oil processing, including, for example, those discussed in: "Practical Guide to Vegetable Oil Processing", 2008, Monoj K. Gupta, AOCS Press and the edible oil processing section of the "AOCS Lipid Library" website (lipidlibrary.aocs.org).

[0072] The further treatment may comprise one or more steps selected from the group consisting of: degumming, bleaching, winterization, decolorization and deodorization. Preferably, the further treatment comprises deodorization and / or bleaching.

[0073] In some cases, at least one further processing step includes degumming, bleaching and deodorizing steps. Alternatively, in other cases, at least one further processing step includes a deodorizing step and the method does not include a degumming and / or bleaching step. Thus, in an exemplary embodiment, at least one further processing step includes a degumming and deodorizing step, but does not include a bleaching step. In other exemplary embodiments, at least one further refining step includes a bleaching and deodorizing step, but does not include a degumming step.

[0074] Another advantage of the organic amine treatment according to the present invention is that it has been found that the treatment at least partially removes pigments and odorous compounds that are usually removed at high temperature deodorization steps (e.g., 240° C. to 270° C.) in conventional refining processes. Treatment of the glyceride oil with an organic amine means that lower temperatures and / or shorter durations can be used in the deodorization step as part of the overall refining process. This has the advantage of reducing the energy requirements of the refining process.

[0075] Degumming generally includes contacting the oil with an aqueous solution of phosphoric acid and / or an aqueous solution of citric acid to remove hydratable and non-hydratable phospholipids (NHP). Typically, citric acid or phosphoric acid is added as a 50wt.% aqueous solution. A suitable amount of aqueous acid is about 0.02% to about 0.20% of the weight of the oil, preferably 0.05% to about 0.10% of the weight of the oil. Suitably, the degumming step is carried out at a temperature of about 50 to 110°C, preferably 80°C to 100°C, such as 90°C. The degumming step can be suitably continued for 5 minutes to 60 minutes, preferably 15 to 45 minutes, more preferably 20 to 40 minutes, such as 30 minutes. After the mucus sedimentation after the acid treatment, the aqueous phase is separated before the degummed oil is usually dried. The drying of the degummed oil is suitably carried out at a temperature of 80 to 110°C, under reduced pressure conditions (e.g., under 2 to 3kPa (20 to 30mbar) pressure) for a suitable duration, such as 20 to 40 minutes.

[0076] As is known to the skilled person, for glyceride oils with a low phospholipid content (e.g., less than 20 ppm by weight of phosphorus), a dry degumming process can be used, in which phosphoric acid or citric acid is added without significant dilution with water (e.g., 85% acid solution). The NHP is converted to phosphatidic acid and calcium or magnesium diphosphates, which can be removed from the oil in a subsequent bleaching step. For oils rich in phospholipids, especially NHP, dry degumming is known to be less suitable because excessive amounts of bleaching earth are required.

[0077] Bleaching is incorporated into the edible oil refining process to reduce color bodies, including chlorophyll, residual soaps and colloids, trace metals and oxidation products. Bleaching generally involves contacting the oil with a certain amount of bleaching clay or earth, for example 0.5 to 5 wt.% clay based on the mass of the oil. The bleaching clay or earth is generally composed of one or more of the following three clay minerals: calcium montmorillonite, attapulgite and sepiolite. Any suitable bleaching clay or earth may be used according to the present invention, including neutral and acid activated clays (e.g. bentonite). The oil is suitably contacted with the bleaching clay for 15 to 45 minutes, preferably 20 to 40 minutes, and then the earth is separated, usually by filtering. The oil is generally contacted with the bleaching clay or earth at a temperature of 80°C to 125°C, preferably 90°C to 110°C. After a first stage of contacting at atmospheric pressure ("wet bleaching"), the second stage of the bleaching process is carried out under reduced pressure ("dry bleaching"), for example at a pressure of 2 to 3 kPa (20 to 30 mbar).

[0078] Conventional glyceride oil refining processes typically include a FFA neutralization step using a strong base (e.g. sodium hydroxide or potassium hydroxide) (corresponding to a so-called "chemical refining" process). Alternatively, deacidification can be achieved by adjusting the deodorization parameters accordingly to ensure that volatile FFAs are removed in this step (so-called "physical refining" process). A disadvantage of the FFA neutralization step ("chemical refining") is that it is accompanied by an unwanted saponification action, which reduces the triglyceride content, while saponification can result in a large amount of neutral oil loss due to emulsification. The organic amine treatment that forms part of the use of the present invention is effective in neutralizing the FFA in the oil and can completely replace the conventional neutralization step used in the chemical refining process. Advantageously, treatment with an organic amine does not result in saponification of the neutral oil. Therefore, in a preferred embodiment of the present invention, the refining process does not include a step of neutralization with an inorganic base (e.g. sodium hydroxide).

[0079] The FFA present in the oil can be neutralized to form a salt when contacted with the organic amine. In a preferred embodiment, the amount of the organic amine used in the contacting step is at least stoichiometrically matched to the molar amount of FFA contained in the oil. For example, the molar ratio of the organic amine to the FFA in the oil can be 1:1 to 10:1, or 1.5:1 to 5:1. The content of FFA in the glyceride oil can be determined using conventional titration techniques known to those skilled in the art before treatment with the organic amine. For example, the FFA content of the glyceride oil can be determined by titration with sodium hydroxide using a phenolphthalein indicator.

[0080] As known to the skilled person, deodorization corresponds to a stripping process, wherein a certain amount of stripping agent is passed through the oil in a distillation apparatus, usually by direct injection, under reduced pressure over a period of time to evaporate and extract volatile components, such as FFA, aldehydes, ketones, alcohols, hydrocarbons, tocopherols, sterols and phytosterols. The stripping agent is preferably steam, but other reagents such as nitrogen may also be used. The suitable usage amount of the stripping agent is from about 0.5wt.% to about 5wt.% of the oil.

[0081] A suitable temperature range for deodorization according to the refining process of the present invention is 160°C to 270°C. When referring to the temperature of the deodorization step herein, this refers to the temperature to which the oil is heated before being exposed to the stripping agent. A suitable pressure range for deodorization is 0.1 to 0.4 kPa (1 to 4 mbar), preferably 0.2 to 0.3 kPa (2 to 3 mbar). A suitable duration for deodorization is typically 30 to 180 minutes, such as 60 to 120 minutes, or 60 to 90 minutes.

[0082] The skilled person is able to determine the appropriate deodorization duration by analyzing the appearance and composition of the glyceride oil. For example, the p-anisidine value (AnV) of the oil is determined. The p-anisidine value of an oil is a measure of its oxidation state, more specifically, the p-anisidine value provides relevant information on the level of secondary oxidation products in the oil, although mainly aldehydes, such as 2-enals and 2,4-dienals. Therefore, the p-anisidine value (AnV) also indicates the level of oxidation products to be removed by the deodorization step. For example, a satisfactory deodorization effect can be obtained when the AnV determined according to AOCS Official Method Cd18-90 is less than 10 (preferably less than 5).

[0083] Additionally or alternatively, the amount of aldehyde and ketone components in the oil (which are usually relevant to the smell of crude oil) can be determined to determine whether sufficient deodorization has been carried out. The typical volatile smell aldehyde and ketone components of crude palm oil or rancid palm oil include: acetaldehyde, benzaldehyde, n-propanal, n-butyraldehyde, n-valeraldehyde, n-hexanal, n-octanal, n-nonanal, 2-butenal, 3-methylbutyraldehyde, 2-methylbutyraldehyde, 2-pentenal, 2-hexenal, 2E, 4E-decadienal, 2E, 4Z-decadienal, 2-butanone, 2-pentanone, 4-methyl-2-pentanone, 2-heptanone, 2-nonanone. Preferably, the amount that each of these components is separately present in the deodorized oil is less than 3mg / kg oil, more preferably less than 1mg / kg oil, most preferably less than 0.5mg / kg oil.

[0084] The amount of aldehydes and ketones can be easily determined by chromatographic methods, such as GC-TOFMS or GCxGC-TOFMS. Alternatively, derivatization of aldehydes and ketones can be used to improve chromatographic analysis. For example, it is known that aldehydes and ketones can be derivatized with 2,4-dinitrophenylhydrazine (DNPH) under acidic conditions. This reagent does not react with carboxylic acids or esters, so the analysis is not affected by such components in glyceride oil samples. After derivatization, HPLC-UV analysis can quantify the total amount of aldehydes and ketones present in the sample.

[0085] Conventional deodorization temperatures are usually above 220°C, such as 240°C to 270°C, and are usually operated for 60 to 90 minutes. The method of the present invention allows for deodorization at a lower temperature than conventional temperatures, such as 160°C to 200°C, and the deodorization time can be extended to ensure sufficient deodorization, but the energy consumption is still lower than conventional deodorization, which is carried out at a higher temperature (e.g., 240°C to 270°C) for a shorter time.

[0086] In a preferred embodiment, due to the aforementioned organic amine treatment, the same degree of deodorization can be achieved by combining a deodorization time that is the same as or lower than the conventional deodorization time with a deodorization temperature that is lower than the conventional deodorization temperature. In other preferred embodiments, the deodorization step included in the refining process of the present invention can reduce the deodorization time (compared with the conventional time) by using a conventional temperature (e.g., 240° C. to 270° C.), and due to the aforementioned organic amine treatment, a comparable deodorization level can still be achieved.

[0087] In a particularly preferred embodiment, at least one further refining step according to the use according to the invention comprises deodorization at a temperature of 160 to 200° C., more preferably 170 to 190° C. Preferably, the deodorization is carried out at these temperatures for a time of 30 to 150 minutes, more preferably 45 to 120 minutes, most preferably 60 to 90 minutes.

[0088] The organic amine treatment according to the use of the invention can be suitably applied to a crude glyceride oil containing metals which has not undergone any previous refining step after oil extraction. Alternatively, the use of the invention can be applied to a glyceride oil which has undergone at least one additional refining step before the treatment with the organic amine. Typically, at least one additional refining step is selected from bleaching and / or degumming.

[0089] An advantage associated with the use according to the invention is that the degumming requirements of the glyceride oil are reduced or eliminated. Phosphorus-containing compounds (e.g. phospholipids) are partly responsible for the formation of gums in glyceride oils and are usually removed during conventional degumming processes. Since the use according to the invention reduces the concentration of phosphorus and phosphorus-containing compounds in the glyceride oil, the requirements for degumming the glyceride oil can be eliminated or reduced. In the case of degumming of the glyceride oil after the organic amine treatment according to the use according to the invention, less acid may be required in the degumming step because many of the phosphorus-containing compounds have been removed according to the use according to the invention.

[0090] In some cases, the use according to the invention does not degumming the glyceride oil before the organic amine treatment. In this case, the use according to the invention may include not further treating the glyceride oil. Alternatively, the use according to the invention does not degumming the glyceride oil before the organic amine treatment, and the use according to the invention includes further treating the glyceride oil, in which case the further treating may not include the degumming process. Therefore, in some cases, the use according to the invention may eliminate the need for degumming in the process of refining the glyceride oil.

[0091] A second aspect of the present invention provides a method for removing phosphorus and / or phosphorus-containing compounds from glyceride oil, the method comprising the following steps:

[0092] (i) contacting a glyceride oil containing phosphorus and / or phosphorus-containing compounds with an organic amine and water to form a treated glyceride oil and water phase; wherein the water is added in an amount of 5% v / v to 40% v / v relative to the organic amine, and the amount of the organic amine is 1 wt.% to 75 wt.% relative to the glyceride oil; wherein phosphorus is present in the glyceride oil in an amount of 0.25 ppm to 10,000 ppm; and the organic amine is selected from:

[0093] N(R a )(R b )(R c ),

[0094] Where: R a , R b and R c Each independently selected from C 1 To C 8 A straight or branched alkyl or C 3 To C 6 A cycloalkyl group; or R a , R b and R c Any two of them combine to form an alkylene chain -(CH 2 )q-, wherein q is 3 to 6; and wherein the alkyl or cycloalkyl group may be optionally substituted with 1 to 3 groups selected from the following: C 1To C 4 Alkoxy, C 2 To C 8 Alkoxyalkoxy, C 3 To C 6 Cycloalkyl, -OH, -NH 2 , -SH, -CO 2 (C 1 To C 6 )alkyl and -OC(O)(C 1 To C 6 ) alkyl; or R a is hydrogen, R b and R c As previously mentioned; and

[0095] (ii) after the glyceride oil is contacted with the organic amine and water, separating the treated glyceride oil from the aqueous phase; wherein the treated glyceride oil has a reduced concentration of phosphorus and / or phosphorus-containing substances compared to the glyceride oil contacted in step (i).

[0096] Preferably, the phosphorus content of the phosphorus-containing glyceride oil is from 1 ppm to 100 ppm, more preferably from 10 ppm to 50 ppm, most preferably from 10 ppm to 20 ppm.

[0097] In some cases, the method of the present invention is a pretreatment process. As used herein, the term "pretreatment process" is used to refer to the treatment of the phosphorus-containing glyceride oil before any other refining steps (e.g., the above steps). Therefore, in some cases, the pretreatment process is performed directly after the phosphorus-containing glyceride oil is extracted and before any other steps of treating the phosphorus-containing glyceride oil.

[0098] Alternatively, where the phosphorus-containing glyceride oil comprises spent oil, the term "pretreatment process" refers to pretreatment prior to any other processing steps of the spent oil and after the spent oil is collected.

[0099] Preferably, the method eliminates or reduces the need for subsequent degumming of the glyceride oil. In some cases, if the glyceride oil is not previously degummed, the method does not include further processing; or the method includes further processing, wherein the further processing does not include a degumming process.

[0100] Any features and preferred features discussed above with respect to the first aspect of the invention are equally applicable to this aspect of the invention. Specifically, all features of the organic amine, phosphorus-containing glyceride oil, phosphorus and phosphorus-containing compounds, contact and separation steps, and further processing discussed above with respect to the first aspect of the invention are equally applicable to the method of the second aspect of the invention.

[0101] The use of the first aspect of the present invention and the method of the second aspect of the present invention may further comprise a step of regenerating the organic amine from the aqueous phase. Preferably, the step of regenerating the organic amine from the aqueous phase comprises vacuum distillation.

[0102] The examples of the invention described above may be combined with any other compatible examples to form further examples of the invention.

[0103] The invention will now be illustrated by the following examples.

[0104] Example

[0105] Crude palm oil (CPO) (130 g, 5.25%, 0.0269 mol FFA) was heated to 50°C. The liquid was stirred at 4000 rpm using a high shear mixer. Aqueous dimethylethanolamine (70% v / v) (DMEA) (2.519 g, 0.0282 mol) was added. The solution was stirred for 15 minutes and then centrifuged. The oil phase was separated from the non-organic phase.

[0106] The FFA level in the separated oil phase was determined by colorimetric titration. Typically, 1 g of oil was dissolved in 25 ml of isopropyl alcohol (IPA), and a few drops of phenolphthalein were added before titrating the solution with 0.1 M potassium hydroxide solution. After treatment with DMEA, the initial FFA value in crude palm oil dropped from 5.25% to 0.3%.

[0107] Phosphorus concentrations in crude palm oil (CPO) and separated treated palm oil (TPO) were calculated using ICP-OES analysis.

[0108] CPO CPO TPO TPO Test 1 Test 2 Test 1 Test 2 Phosphorus content (ppm) 14.6 18.6 0.32 0.41

[0109] The above examples demonstrate that organic amines can reduce the phosphorus content of phosphorus-containing glyceride oils. These examples also demonstrate that organic amines reduce the free fatty acid concentration of metal-containing glyceride oils. The permitted limit of phosphorus in refined bleached deodorized palm oil (RBDPO) is 5ppm. Therefore, the above examples demonstrate that organic amine treatment can reduce the phosphorus content of crude vegetable oils to the specification of RBDPO.

Claims

1. A method for removing phosphorus and / or phosphorus-containing compounds from a glyceride oil, the method comprising the following steps: (i) contacting a glyceride oil containing phosphorus and / or phosphorus-containing compounds with an organic amine and water to form a treated glyceride oil and water phase; wherein the water is added in an amount of 5% v / v to 40% v / v relative to the organic amine, and the amount of the organic amine is 1 wt.% to 75 wt.% relative to the glyceride oil; wherein phosphorus is present in the glyceride oil in an amount of 0.25 ppm to 10,000 ppm; and the organic amine is dimethylethanolamine: and (ii) after the glyceride oil is contacted with the organic amine and water, separating the treated glyceride oil from the aqueous phase; wherein the treated glyceride oil has a reduced concentration of phosphorus and / or phosphorus-containing substances compared to the glyceride oil contacted in step (i).

2. The method according to claim 1, wherein the phosphorus content of the glyceride oil is from 1 ppm to 100 ppm.

3. The method of claim 1, wherein the phosphorus content of the glyceride oil is 10 ppm to 50 ppm.

4. The method of claim 1, wherein the phosphorus content of the glyceride oil is 10 ppm to 20 ppm.

5. The method according to claim 1 or 2, wherein water is added in an amount of 15% v / v to 40% v / v relative to the organic amine.

6. The method according to claim 1 or 2, wherein water is added in an amount of 25% v / v to 35% v / v relative to the organic amine.

7. The method according to claim 1 or 2, wherein water is added in an amount of 30% v / v relative to the organic amine.

8. The method according to claim 1 or 2, wherein the amount of the organic amine used is 1 wt.% to 40 wt.% relative to the glyceride oil.

9. The method according to claim 1 or 2, wherein the amount of the organic amine used is 1 wt.% to 20 wt.% relative to the glyceride oil.

10. The method according to claim 1 or 2, wherein the organic amine is used in an amount of 2 wt.% to 8 wt.% relative to the glyceride oil.

11. The method according to claim 1 or 2, wherein the amount of the organic amine used is 4 wt.% to 6 wt.% relative to the glyceride oil.

12. The method according to claim 1 or 2, wherein the amount of the organic amine used is 5 wt.% relative to the glyceride oil.

13. The method of claim 1 or 2, wherein the organic amine is contacted with the glyceride oil at a temperature below 80°C.

14. The method of claim 1 or 2, wherein the organic amine is contacted with the glyceride oil at a temperature of 25 to 70°C.

15. The method of claim 1 or 2, wherein the organic amine is contacted with the glyceride oil at a temperature of 35 to 65°C.

16. The method of claim 1 or 2, wherein the organic amine is contacted with the glyceride oil at a temperature of 45 to 55°C.

17. The method of claim 1 or 2, wherein the organic amine is contacted with the glyceride oil at a temperature of 50°C.

18. The method of claim 1 or 2, wherein contacting the glyceride oil with the organic amine comprises: The mixture of the organic amine and the metal-containing glyceride oil is stirred.

19. The method of claim 18, wherein stirring is performed with a shear mixer.

20. The method of claim 18, wherein the mixture is stirred for 5 to 30 minutes.

21. The method of claim 1 or 2, wherein the phosphorus and / or phosphorus-containing compound comprises a phospholipid, a phospholipid, or a combination thereof.

22. The method of claim 1 or 2, wherein the glyceride oil is a vegetable oil.

23. The method of claim 22, wherein the vegetable oil is selected from the group consisting of coconut oil, corn oil, cottonseed oil, peanut oil, olive oil, palm oil, rapeseed oil, rice bran oil, safflower oil, soybean oil and sunflower oil, or mixtures thereof.

24. The method of claim 1 or 2, wherein the glyceride oil comprises spent oil.

25. The method of claim 24, wherein the used vegetable cooking oil.

26. The method of claim 1 or 2, wherein the total concentration of phosphorus in the separated treated glyceride oil is less than 50 wt.% of the total concentration of phosphorus in the glyceride oil contacted with the organic amine.

27. The method of claim 1 or 2, wherein the total concentration of phosphorus in the separated treated glyceride oil is less than 25 wt.% of the total concentration of phosphorus in the glyceride oil contacted with the organic amine.

28. The method of claim 1 or 2, wherein residual organic amines are removed from the treated glyceride oil.

29. The process of claim 28, wherein the residual organic amine is removed from the glyceride oil at least in part by vacuum distillation or vacuum drying.

30. The method of claim 29, wherein the vacuum distillation is performed at a temperature of 25 to 70°C.

31. The method of claim 29, wherein the vacuum distillation is performed at a temperature of 35 to 65°C.

32. The method of claim 29, wherein the vacuum distillation is performed at a temperature of 45 to 55°C.

33. The method of claim 29, wherein the vacuum distillation is performed at a temperature of 50°C.

34. The method of claim 1 or 2, wherein the treated glyceride oil undergoes further processing.

35. The method of claim 34, wherein the further processing comprises one or more steps selected from the group consisting of degumming, bleaching, winterization, bleaching and deodorization.

36. The method of claim 1 or 2, wherein the method eliminates or reduces the need for subsequent degumming of the glyceride oil.

37. The method of claim 1 or 2, wherein the glyceride oil has not been previously degummed, and wherein (i) the method does not comprise further processing, or (ii) the method comprises further processing, wherein the further processing does not comprise a degumming process.

38. The method according to claim 1 or 2, further comprising the step of regenerating the organic amine from the aqueous phase.

39. The method of claim 38, wherein the step of regenerating the organic amine from the aqueous phase is performed by vacuum distillation.

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