Method for removing chlorine-containing compounds and other impurities from fats and oils

Abstract

The present invention relates to a novel process for removing chlorine-containing compounds and other impurities from fats and oils.

Description

Technical Field

[0001] The present invention relates to a method for purifying raw materials rich in organic chlorides, such as, for example, brown grease, gutter oil or low-quality UCO, by partial hydrolysis with water or thermal treatment, which removes about 90% of the organic chlorides present in the raw material, in addition to more than 95% of phosphorus and a large amount of metals. Background Art

[0002] In order to fully utilize very low quality fats and oils, new and efficient pre-processing and pre-treatment methods are clearly needed to reduce the amount of harmful impurities in challenging feedstocks. Chlorine compounds, both inorganic and organic, are particularly problematic because chlorides can corrode metal surfaces and equipment by initiating stress corrosion cracking. Current state of the art bleaching processes using citric acid and bleaching earth are effective in removing phosphorus and metals from several high and medium quality feedstocks. However, the amount of organic chlorides is not reduced during the bleaching process. In fact, the amount of organic chlorides tends to increase under acidic bleaching conditions as inorganic chloride salts are converted to "difficult to remove" organic chlorides.

[0003] Thus, there is a clear need to be able to use low or very low quality feedstocks for further processing to make those feedstocks economically viable options for use in, for example, the production of renewable fuel sources.

[0004] The present invention solves this problem and in particular provides a new method for processing low quality or even very low quality feedstocks, thereby enabling an improved and cost-effective method of processing such feedstocks for further use in, for example, fuel preparation. Summary of the invention

[0005] As described herein, the present invention provides a highly efficient method for processing feedstocks to reduce the content of, for example, organochlorine compounds to levels that allow the purified feedstock to be used for further processing.

[0006] The present invention solves the problem of removing, for example, chlorine-containing compounds to a level that enables further processing of the purified feedstock and avoids the problems associated with higher levels of chlorine-containing compounds present in the feedstock. Such problems could be, for example, corrosion of any equipment used in any further processing, or fouling of the catalyst.

[0007] Thus, the present invention provides various aspects, including, for example, a simplified and efficient new process. This may include omitting steps or operations present in the prior art, while obtaining a product with a sufficiently low contaminant content, purified oil or raw material to allow further processing.

[0008] In one aspect, the invention relates to a method or process for purifying a feedstock.

[0009] In one aspect, the method or process may include one or more steps:

[0010] a) provide raw materials,

[0011] b) mixing or contacting the raw materials with water,

[0012] c) heating the feedstock / water mixture obtained in step b),

[0013] d) separating the aqueous phase and the oil phase obtained in step c),

[0014] e) removing solids from the oil phase obtained in step d),

[0015] To obtain an oil phase substantially free of or with a reduced amount of chlorine-containing compounds.

[0016] In one aspect, the method according to the invention comprises steps a) to e) without any process steps or reactions between any of said steps.

[0017] In another aspect, the method according to the invention is performed, i.e. step a) is performed first, then step b) is performed, then step c), and so on.

[0018] In another aspect, the method according to the present invention may include other steps before, and / or after, or between any of steps a) to e).

[0019] The present invention also relates to a raw material obtainable by the method of the present invention. In other words, the present invention enables the preparation of a purified raw material by employing the method of the present invention.

[0020] The invention also relates to a feedstock, characterized in that the feedstock contains very low or no chlorine-containing compounds. The invention also relates to a feedstock having low or no phosphorus-containing compounds and / or metal-containing compounds.

[0021] Various aspects of the present invention will be further described in the following detailed description. DETAILED DESCRIPTION

[0022] As described herein, the present invention is directed to a method or process for purifying a feedstock.

[0023] In one aspect, the method may include the steps of:

[0024] a) provide raw materials,

[0025] b) mixing or contacting the raw materials with water,

[0026] c) heating the feedstock / water mixture obtained in step b),

[0027] d) separating the aqueous phase obtained in step c) from the oil phase,

[0028] e) removing solids from the oil phase obtained in step d),

[0029] To obtain an oil phase substantially free of or with a reduced amount of chlorine-containing compounds.

[0030] It should be understood that throughout the specification, the terms "method" and "process" are used interchangeably.

[0031] According to the invention, the starting material to be purified may be of any plant, animal origin or, in principle, may originate from any organism.

[0032] In one aspect, the present invention does not involve any feedstock of fossil origin, or of synthetic origin.

[0033] In one aspect, the feedstock according to the present invention can be waste cooking oils, trap and brown greases, low quality waste cooking oils (UCO), low quality animal fats, or any mixture thereof. Thus, the present invention and its method are able to utilize feedstocks that are normally considered to be too low quality to be further used for any purpose.

[0034] In other words, the feedstock to be purified or processed according to the method of the invention may be of any plant or animal origin and may therefore be based on: any part, derivative or product based on any plant or animal, or any product derived from or based on algae or microbial oils. Thus, in a broader understanding of the present invention, the term "feedstock" may include one or more of any vegetable oil, vegetable fat, animal fat and animal oil and fungal oil, selected from, for example, waste cooking oil (UCO), rapeseed oil, canola oil, colza oil, tall oil, sunflower oil, corn oil, industrial / distilled corn oil (TCO), soybean oil, hemp oil, olive oil, linseed oil, cottonseed oil, mustard oil, palm oil, palm oil mill effluent (POME) oil, peanut oil, castor oil, coconut oil, animal fats (such as, for example, suet, tallow, whale blubber, recycled edible fats), fish oil, starting materials produced by genetic engineering, and biological starting materials produced by microorganisms such as algae and bacteria, etc., acidulated soapstock (acidified soapstock), grease trap grease, brown grease, waste cooking oil, fatty acid distillates (FAD) (from, for example, rice bran oil or from palm oil (palm oil fatty acid distillate PFAD)), or any combination or mixture thereof.

[0035] Regarding feedstock, “waste cooking oil (UCO)” refers to oils and fats used for cooking or frying in the food processing industry, restaurants, fast food and at the household consumer level.

[0036] Waste cooking oil and fat is a common term for waste oil collected from sources such as fryers, grease traps, slaughterhouse waste and grease blocks.

[0037] The term "brown grease" is intended to mean any emulsion of fats, oils, grease, solids, and water separated from wastewater in grease interceptors (grease traps) and collected for use as fuel feedstock.

[0038] As will be apparent from the foregoing, the feedstock may include any oil or lipid material obtained from any animal or plant source, and / or may include any oil or lipid material obtained from any type of fungi (such as, for example, yeast, bacteria, protists (such as, for example, algae and protozoa), and prokaryotes (such as, for example, eubacteria, archaea, etc.).

[0039] In another aspect, the feedstock may include one or more vegetable oils, vegetable fats, animal fats and oils, microbial oils; or the feedstock may include waste cooking grease, grease trap grease and brown grease, low quality waste cooking oil (UCO), low quality animal fats, or any mixture thereof.

[0040] The present invention aims to provide a purified feedstock having a reduced amount of chlorine-containing compounds. The chlorine-containing compounds may be organic or inorganic chlorine-containing compounds or mixtures thereof.

[0041] The term "reduction" is intended to mean that the amount of a component present in any material (such as, for example, a raw material) is lower relative to its amount present in any material before any processing, or its amount present in, for example, a raw material used as a starting material or raw material in any process. Reduction can mean that one or more components are reduced by 100%, so that they are basically completely removed, or reduced by at least about 20%, such as, for example, reduced by at least about 30%, such as, for example, reduced by at least about 40%, such as, for example, reduced by at least about 50%, such as, for example, reduced by at least about 60%, such as, for example, reduced by at least about 70%, such as, for example, reduced by at least about 80%, such as, for example, reduced by at least about 85%, such as, for example, 90%, such as, for example, at least about 95%, such as, for example, at least about 97%, such as, for example, at least about 98%, such as, for example, at least about 99%. This percentage can be measured by weight % (wt%) or volume % (vol%) or mole %, or can be a measurement of the ratio between the remaining amount of chlorine-containing compounds in, for example, purified raw materials compared to unpurified raw materials.

[0042] In one aspect, the present invention is capable of reducing the amount of one or more chlorine-containing compounds, phosphorus-containing compounds, and metal-containing compounds present in the raw material to such an extent that the residual level of the compound is below the analytical detection level. In this regard, the analytical method for determining the compound in the purified raw material is intended to mean any method known in the art.

[0043] In one particular aspect, the present invention is capable of reducing or removing organic chlorine-containing compounds. Specifically, the term "organic chlorine-containing compound" is intended to mean a compound in which a chlorine atom is covalently bonded to a carbon atom. A non-limiting example of such a chlorine-containing compound may be, for example, 3-MCPD ester (fatty acid ester of 3-chloro-1,2-propanediol). However, it should be noted that a number of other organic chlorine-containing compounds may be removed from the feedstock by the method of the present invention.

[0044] The present invention also enables the amount of phosphorus-containing compounds to be reduced.

[0045] The present invention also enables the amount of metal-containing compounds present in the purified feed to be reduced.

[0046] In one aspect, the present invention can reduce at least one of chlorine-containing compounds, phosphorus-containing compounds, and metal-containing compounds present in the feedstock. In another aspect, the present invention can reduce all three of chlorine-containing compounds, phosphorus-containing compounds, and metal-containing compounds present in the feedstock.

[0047] As mentioned herein, raw material is so-called low-quality raw material. In the context of the present invention, term " low-quality " is intended to represent a kind of raw material, it can comprise about 50 ppm or higher chloride content, such as for example about 75 ppm or higher, such as for example about 100 ppm or higher, such as for example about 125 ppm or higher, such as for example about 150 ppm or higher, such as for example about 175 ppm or higher, such as for example about 200 ppm or higher, such as for example about 225 ppm or higher. However, raw material can also comprise at least about 50 ppm chloride content, such as for example at least about 100 ppm, such as for example at least about 150 ppm, such as for example at least about 200 ppm, such as for example at least about 250 ppm, such as for example at least about 500 ppm, such as for example at least about 750 ppm, such as for example at least about 1000 ppm, such as for example at least about 1500 ppm, such as for example at least about 1750 ppm, such as for example at least about 2000 ppm. As referred to herein, "chloride content" may be the total amount of inorganic and organic chlorine compounds present in the feedstock, or may refer only to the amount of organic or inorganic chlorine compounds, respectively, present in the feedstock.

[0048] According to the present invention, the feedstock is mixed or otherwise contacted with water.

[0049] In one aspect, contacting of the feedstock with water can be shown in step b).

[0050] The amount of water used in the method can be, for example, a ratio of raw material to water (w / w) of about 1:1, such as, for example, about 2:1, such as, for example, about 3:1, such as, for example, about 4:1, such as, for example, about 5:1, such as, for example, about 6:1, such as, for example, about 7:1, such as, for example, about 8:1, such as, for example, about 9:1, such as, for example, about 10:1, etc. Alternatively, the ratio can be in any range from about 4:1 to about 9:1. Alternatively, the amount of water can also be about 5 wt% (relative to the weight of the raw material), such as, for example, about 10 wt%, such as, for example, about 20 wt%, such as, for example, about 25 wt%, such as, for example, about 30 wt%, such as, for example, about 40 wt%, or alternatively in any range from about 10 wt% to about 25 wt%.

[0051] In one aspect, the amount of water added can be in any range, for example, from about 5 wt % to about 10 wt % relative to the provided feedstock.

[0052] In yet another aspect, the amount of water added can be, for example, 5 wt % relative to the provided raw material. In another aspect, the amount of water added can be, for example, about 10 wt % relative to the provided raw material.

[0053] In one aspect, the added water can contain no base or basic compound, such as, for example, an alkali metal hydroxide, an alkali metal carbonate, an alkali metal alkoxide, or any combination thereof.

[0054] In general, the method according to the present invention may not include the use of basic compounds as a whole, such as, for example, alkali metal hydroxides, alkali metal carbonates, alkali metal alkoxides, or any combination thereof.

[0055] In another aspect, the added water does not contain alcohols, such as, for example, methanol or ethanol.

[0056] In general, the process according to the invention as a whole may not comprise the use of alcohols, such as, for example, methanol or ethanol, or any combination thereof.

[0057] Contacting of the feedstock with water may be achieved by any standard method known in the art. Non-limiting examples may be, for example, any type of mechanical stirring or agitation, or, for example, high shear mixing.

[0058] In one aspect, the feedstock / water mixture may be heated. The heating step according to the invention may be exemplified by step c) according to the invention.

[0059] In a further aspect, the heating step c) can be performed at ambient pressure, such as, for example, about 1.0 standard atmosphere (atm).

[0060] In another aspect, the heating step c) may not include applying additional pressure.

[0061] In yet another aspect, the heating step can exclude heating under an inert atmosphere, such as, for example, heating in the presence of nitrogen or argon.

[0062] The temperature at which the heating is performed may be a temperature in the range of about 200°C to about 300°C, such as, for example, about 210°C, such as, for example, about 220°C, such as, for example, about 230°C, such as, for example, about 240°C, such as, for example, about 250°C, such as, for example, about 260°C, such as, for example, about 270°C, such as, for example, about 280°C, such as, for example, about 290°C. Alternatively, the temperature may be in any range of about 210°C to, for example, about 290°C, such as, for example, about 220°C to, for example, about 280°C, such as, for example, about 230°C to, for example, about 270°C.

[0063] In one aspect, the temperature can be, for example, about 260°C.

[0064] In another aspect, the temperature can be, for example, about 230°C.

[0065] In yet another aspect, the temperature can be in the range of, for example, about 230°C to about 260°C.

[0066] In one aspect, the pressure needs to be above the vapor pressure of water at the temperature used to keep the water in liquid form.

[0067] The heating in the method according to the invention, which may be indicated in step c), may be carried out for any suitable time.

[0068] The heating may be carried out for a time period of, for example, from about 1 minute to about 60 minutes, or from 1 h to about 6 h, such as, for example, about 2 h, such as, for example, about 3 h, such as, for example, about 4 h, such as, for example, about 5 h, or alternatively for at least 1 minute, such as, for example, at least about 5 minutes, at least about 10 minutes, at least about 15 minutes, at least about 20 minutes, at least about 15 minutes, at least about 20 minutes, at least about 25 minutes, at least about 30 minutes, at least about 35 minutes, at least about 40 minutes, at least about 45 minutes, at least about 50 minutes, at least about 55 minutes, at least about 50 minutes.

[0069] In one aspect, heating can be performed for a time period of, for example, 1 minute, such as, for example, at least about 5 minutes, at least about 10 minutes, at least about 15 minutes, at least about 20 minutes, at least about 15 minutes, at least about 20 minutes, at least about 25 minutes, at least about 30 minutes, at least about 35 minutes, at least about 40 minutes, at least about 45 minutes, at least about 50 minutes, at least about 55 minutes, at least about 50 minutes, or for at least about 60 minutes.

[0070] In yet another aspect, heating can be performed for, for example, about 5 minutes.

[0071] In another aspect, heating can be performed for, for example, about 30 minutes.

[0072] In one aspect, heating can be performed for, for example, about 60 minutes.

[0073] In one aspect, heating can be performed for, for example, about 3 h.

[0074] Without being bound by any theory, heating of the feedstock / water mixture results in the formation of solid phosphorus-containing compounds and / or metal-containing compounds.

[0075] Furthermore, heating the feedstock / water mixture may partially hydrolyze triglycerides present in the feedstock into free fatty acids and diglycerides and / or monoglycerides. Thus, partial hydrolysis of triglycerides may be a result of the process according to the invention.

[0076] According to the present invention, it is not necessary to completely hydrolyze the triglycerides present in the provided feedstock. In one aspect, the present invention relates to at least partial hydrolysis of the triglycerides present in the provided feedstock.

[0077] In one aspect, the method can provide for minimal hydrolysis of, for example, triglycerides in the feedstock by treatment with water.

[0078] After the heating in step c) is completed, the water or aqueous phase can be separated from the oil phase. This operation can be shown or exemplified by step d).

[0079] The separation of water or aqueous phase and oil phase or organic phase can in principle be carried out by any suitable technique known in the art. Non-limiting examples of this can be, for example, centrifugation, spontaneous phase separation, sedimentation, decantation, evaporation of water, or any combination thereof in any order.

[0080] The oily or organic phase obtained from the water separation in step d) may be subjected to any type of filtration or other known technique for removing solids from fluids, thereby removing any solid material present in the oily phase.

[0081] Non-limiting methods for separating any solids from the oil phase can be, for example, filtration using a pre-coating filtration device (e.g., vertical leaf filters, candle filters, drum filters, horizontal filter presses) or by filtration without filter aids (e.g., backwash filters, belt and continuous cake filters, scraped filters), or any combination thereof.

[0082] As described herein, the method according to the present invention may or may not include any method or process step, for example, before step a) or after step e). A non-limiting example is that the method may include additional process or method steps, for example, after step e). In an exemplary aspect, the purified feedstock, i.e., the oil phase obtained from step e), may be subjected to, for example, a bleaching step and / or a degumming step.

[0083] The bleaching step and the techniques employed therein may include the use of any suitable bleaching clay and / or organic acid. The bleaching clay may be of any type, for example various types of hydrated aluminium silicates or bleaching earths, such as, for example, bentonite, attapulgite and sepiolite. Such materials may be acid activated. Suitable acids may be, for example, citric acid, oxalic acid or fumaric acid.

[0084] Typically, the acid used alone or in combination with, for example, any type of bleaching earth may be, for example, citric acid, oxalic acid, or fumaric acid, as non-limiting examples.

[0085] In one aspect, a bleaching clay can be used in combination with an organic acid to bleach the resulting oil phase.

[0086] Bleaching can be carried out under the same conditions as contact between the raw material and water and subsequent heating of the mixture.

[0087] Non-limiting conditions for bleaching can be, for example, any suitable temperature, such as, for example, in the range of about 15°C to about 120°C, or about 50°C to about 90°C, about 60°C to about 95°C, or about 70°C to about 90°C, or about 80°C to about 90°C, or about 85°C, or about 75°C, or preferably about 85°C.

[0088] In addition, bleaching can be carried out within a time period of about 30 seconds to about 1 hour before adding and mixing the adsorbent, such as, for example, about 30 minutes, such as, for example, about 20 minutes, such as, for example, about 15 minutes, such as, for example, about 10 minutes, such as, for example, about 5 minutes, such as, for example, about 3 minutes, such as, for example, about 1 minute.

[0089] In one aspect, bleaching can be performed over a time period of, for example, about 20 minutes.

[0090] Thus, in one aspect, bleaching can be performed at about 85°C for about 20 minutes.

[0091] Bleaching can be carried out under reduced pressure. Reduced pressure can be in principle lower than normal pressure (1 standard atmosphere, the corresponding 1013.25 millibars of standard atmosphere), such as for example at about 100 millibars to about 900 millibars, such as for example about 200 millibars to about 900 millibars, such as for example about 300 millibars to about 900 millibars, such as for example about 400 millibars to about 900 millibars, such as for example about 500 millibars to about 900 millibars, such as for example about 600 millibars to about 900 millibars, such as for example about 700 millibars to about 900 millibars or preferably about 800 millibars pressure.

[0092] In one aspect, bleaching can be carried out under a reduced pressure of about 800 mbar.

[0093] As described herein, the bleaching step may also be a combined bleaching and degumming process under the same conditions as described for the bleaching process.

[0094] The invention provides a high yield method.Therefore, in one aspect, the oil phase present in the crude unpurified raw material is recovered, and at least about 90% of the oil present in the raw material is recovered, such as for example about 95%, such as for example about 98% or such as for example about 99% or the quantitative yield of the oil phase for example present in the raw material.

[0095] The chloride content in the purified raw material obtained (i.e., the oil phase obtained from the method) is reduced by about 85% or more, such as, for example, about 90% or more, such as, for example, about 95% or more, such as, for example, about 98% or more, or reduced to an amount below the analytical detection level relative to the raw material provided in step a).

[0096] In addition, the amount of phosphorus-containing compounds present in the feedstock and before the purification method according to the present invention is reduced by at least about 70% or more, such as, for example, about 80%, such as, for example, about 85% or more, such as, for example, about 90% or more, such as, for example, about 95% or more, such as, for example, about 98% or more, or to an amount below the analytical detection level relative to the feedstock provided in step a).

[0097] In one aspect, the method according to the present invention can also reduce the amount of metal-containing compounds present in the unpurified raw material. The metal content of the resulting oil phase obtained from the method can be reduced by at least about 20% or more relative to the raw material provided in step a), such as, for example, about 30% or more, such as, for example, about 40% or more, such as, for example, about 50% or more, such as, for example, about 60% or more, or, for example, about 70% or more, such as, for example, about 80%, such as, for example, about 85% or more, such as, for example, about 90% or more.

[0098] The method or process according to the invention also provides an oil phase obtained which exhibits a beneficial filtration resistance, such that the obtained oil phase can be further processed without the need for additional expensive operations.

[0099] In one aspect, the filtration resistance is, for example, less than about 1800 GPas / kg. 2 , such as 1700 GPas / kg 2 or less, such as, for example, 1500 GPas / kg 2 or less, such as 1300 GPas / kg 2 or less, such as 1000 GPas / kg 2 or less, such as 750 GPas / kg 2 or less, such as 600 GPas / kg 2 or less, or such as 400 GPas / kg 2 or less.

[0100] In a further aspect, the present invention relates to a method for purifying a feedstock, the method comprising the steps;

[0101] a) provide raw materials,

[0102] b) mixing or contacting the feedstock with water, wherein the feedstock:water ratio is in the range of about 1:1 to about 9:1, preferably about 4:1,

[0103] c) heating the feed / water mixture obtained from step b), wherein the temperature is any range from about 200°C to about 300°C, preferably about 230°C to about 260°C, and wherein the feed / water mixture is heated for any time period from about 1 h to about 6 h, preferably about 3 h,

[0104] d) separating the aqueous phase and the oil phase obtained in step c),

[0105] e) removing solids from the oil phase obtained in step d),

[0106] to obtain an oil phase substantially free of or with a reduced amount of chlorine-containing compounds, and wherein step e) is optionally followed by bleaching.

[0107] According to the present invention, the method of the present invention can provide one or more of the following:

[0108] - a simplified method or procedure in the sense that it does not require the application of pressure, is not carried out under an inert atmosphere, does not require the addition of other reagents, such as for example alkaline components or reagents,

[0109] - A method for effectively removing or reducing organic chlorine-containing compounds, or inorganic chlorine-containing compounds, or a combination of organic and inorganic chlorine-containing compounds.

[0110] - Reduce filtration resistance or processed raw materials.

[0111] - Maximizing the yield of purified raw material obtained, or conversely minimizing the loss of oil during processing.

[0112] Importantly, the present invention is able to provide a simplified, cost-effective process while being able to eliminate or reduce chlorine-containing compounds in an industrial scale environment. Thus, the present invention minimizes the number of reaction steps, minimizes the use of added components, and provides a purified product containing acceptable levels of chlorine-containing compounds for further processing or refining, with a maximized yield of the purified feedstock / oil obtained.

[0113] The invention also relates to an oily phase obtained from a process or method according to the invention.

[0114] In another aspect, the present invention also relates to an oil phase or purified raw material. As is apparent from the description, the oil phase or purified oil phase is intended to mean the product obtained as a result of the raw material being subjected to various steps and treatments according to the method of the present invention.

[0115] The oil phase or purified feed can be characterized as including a total chloride content of less than about 9 ppm, such as, for example, less than about 7 ppm, such as, for example, less than about 5 ppm, such as, for example, less than about 3 ppm, such as, for example, less than about 2 ppm, less than about 1 ppm, etc.

[0116] The oil phase or purified feedstock may be further characterized by including a phosphorus content of less than about 5 ppm, such as, for example, less than about 3 ppm, such as, for example, less than about 2 ppm, less than about 1 ppm, such as, for example, less than about 0.5 ppm, such as, for example, less than about 0.3 ppm, such as, for example, less than about 0.1 ppm.

[0117] The oil phase or purified feedstock is further characterized by comprising a metal content of less than about 250 ppm, such as, for example, less than about 100 ppm, such as, for example, about 50 ppm, such as, for example, less than about 30 ppm, such as, for example, less than about 25 ppm, such as, for example, less than about 20 ppm, such as, for example, less than about 15 ppm, such as, for example, less than about 10 ppm.

[0118] The present invention will be further illustrated in the following non-limiting examples.

[0119] Example

[0120] In the following examples, P is intended to mean a phosphorus-containing compound, N is intended to mean a nitrogen-containing compound, M is intended to mean a metal-containing compound, FFA is intended to mean free fatty acid, BG is intended to mean brown grease, CA is intended to mean citric acid, BE is intended to mean bleaching earth, and HT is intended to mean heat-treated.

[0121] Embodiment 1:

[0122] Brown grease (BG) heat treatment, oil: water ratio 1:1

[0123] Brown grease FFA (free fatty acids) = 90.2%, N = 127.8 ppm, P = 18.9 ppm, total metals = 835.5 ppm, total chlorides = 51.2 ppm, and organic chlorides = 51.8 ppm, mixed 1:1 with water and stirred at 230°C for 3 h. The aqueous and oil phases were separated by centrifugation and the oil phase was filtered to remove any solids. The product contained 92.6% FFA and the removal rates were: N 35.1% (127.8 to 82.9 ppm), P 98.5% (18.9 to 0.3 ppm) and metals 93.0% (835.5 to 58.3 ppm), total chlorides 88.8% (51.2 to 5.7 ppm) and organic chlorides 88.1% (51.8 to 6.2 ppm). Oil recovery 92.9%.

[0124] Example 1.1

[0125] BG Reference Bleach

[0126] Brown grease was bleached with citric acid (7000 ppm) + Tonsil reference, removing N 25.4% (127.8 to 95.3 ppm), P 84.6% (18.9 to 2.9 ppm), metals 98.9% (835.5 to 9.6 ppm) and total chlorides 0.3% (51.2 to 51.0 ppm).

[0127] Embodiment 2:

[0128] Grease trap heat treatment, oil:water ratio 4:1, followed by bleaching

[0129] Grease trap grease, FFA = 60.8%, N = 384 ppm, P = 26.1 ppm, total metals = 898 ppm, total chlorides = 90.5 ppm and organic chlorides = 68.6 ppm, was mixed with water in a ratio of 4:1 and stirred at 260°C for 3 h. The aqueous and oil phases were separated in a separatory funnel and the oil phase was filtered to remove any solids. The product contained 83.7% FFA and the removals were: total chlorides 87.5% (90.5 to 11.3 ppm), organic chlorides 93.3% (68.6 to 4.6 ppm) and P 96.6% (26.1 to 0.9 ppm). Oil recovery 96.6%. The oil phase was bleached with 1000 ppm CA, 1 wt-% BE Tonsil under standard bleaching conditions. Total removal rates are: total chloride 92.8% (90.5 to 6.5 ppm), N 4.2% (384 to 368 ppm), P 98.1% (26.1 to 0.5 ppm) and metals 73.3% (898 to 240 ppm). Filtration resistance 1300 GPas / kg 2 .

[0130] Example 2.1:

[0131] Grease trap grease is heat treated with a 9:1 oil:water ratio followed by bleaching.

[0132] Grease trap grease, FFA = 60.8%, N = 384 ppm, P = 26.1 ppm, total metals = 898 ppm, total chlorides = 90.5 ppm and organic chlorides = 68.6 ppm, was mixed with water 9:1 and stirred at 260°C for 3 h. The aqueous and oil phases were separated in a separatory funnel and the oil phase was filtered to remove any solids. The product contained 76.4% FFA and the removals were: total chlorides 89.8% (90.5 to 9.2 ppm) and organic chlorides 91.2% (68.6 to 6.0 ppm) and P 96.6% (26.1 to 0.9 ppm). Oil recovery 97.6%.

[0133] The oil phase was bleached under standard bleaching conditions with 1000 ppm CA, 1 wt-% BE Tonsil. Total removals were: total chlorides 92.2% (90.5 to 7.1 ppm), N 26.0% (384 to 284 ppm), P 97.7% (26.1 to 0.6 ppm) and metals 72.5% (898 to 247 ppm). Filtration resistance 1700 GPas / kg 2 .

[0134] Example 2.2:

[0135] Grease trap grease refer to bleaching.

[0136] Grease trap grease was bleached with citric acid (1000 ppm) + 1 wt-% of BE Tonsil reference, removing total chloride 18.1% (90.5 to 74.1 ppm), N 24.7% (384 to 289 ppm), P 58.6% (26.1 to 10.8 ppm), metals 48.3% (898 to 464 ppm). Filtration resistance 13076 GPas / kg 2 .

[0137] Example 2.3:

[0138] Grease trap grease is heat treated without the addition of water and subsequently bleached.

[0139] Grease trap grease, FFA = 60.8%, N = 384 ppm, P = 26.1 ppm, total metals = 898 ppm, total chlorides = 90.5 ppm and organic chlorides = 68.6 ppm, heat treated at 260°C for 5 minutes. Due to the very slow 2 μm filtration rate, only a small portion was filtered and only the P and metals in the filtered sample were analyzed, the rest came from the unfiltered sample. Removal from the filtered sample: P 48.8% (26.1 to 13.3 ppm), metals 6.1% (898 to 843 ppm). Removal from the unfiltered sample: total chlorides 9.7% (90.5 to 81.7 ppm), organic chlorides 48.8% (68.6 to 35.1 ppm), N -11.6% (384 to 428 ppm). The filtered heat-treated HT product was bleached with 1000 ppm CA, 1 wt-% BE Tonsil under standard bleaching conditions. Total removals were: total chloride 58.0% (90.5 to 38 ppm), N 11.4% (384 to 340 ppm), P 81.2% (26.1 to 4.9 ppm) and metals 53.3% (898 to 420 ppm). Filtration resistance 6564 GPas / kg 2 .

[0140] Embodiment 3:

[0141] Thermal treatment of waste cooking oil, oil:water ratio 4:1, followed by bleaching

[0142] Waste cooking oil, FFA = 16%, N = 532 ppm, P = 20 ppm, total metals = 400 ppm, total chlorides = 75 ppm and organic chlorides = 55 ppm, was mixed with water in a ratio of 4:1 and stirred at 230°C for 3 h. The aqueous and oil phases were separated in a separatory funnel and the oil phase was filtered to remove any solids. Oil recovery was 98.8%. The oil phase was bleached under standard bleaching conditions with 1000 ppm CA, 1 wt-% BE Tonsil. The product contained 72.5% FFA and the removal rates were: total chlorides 97% (75 to 2.6 ppm), organic chlorides 95% (55 to 2.6 ppm), N 24% (532 to 406 ppm), P 99% (20 to 0.2 ppm) and metals 98% (400 to 7.9 ppm). Filtration resistance was 400 GPas / kg 2 .

[0143] Example 3.1

[0144] Waste cooking oil reference bleaching.

[0145] Waste cooking oil was bleached with citric acid (1000 ppm) + 1 wt-% of BE Tonsil reference, removing total chloride 25% (75 to 56 ppm), N 34% (532 to 351 ppm), P 80% (20 to 4.1 ppm), metals 92% (400 to 32 ppm). Filtration resistance 23956 GPas / kg 2 .

[0146] Example 4

[0147] Heat treatment of Chinese waste edible oils and fats, oil:water ratio 4:1, followed by bleaching

[0148] Chinese waste edible oils and fats, FFA = 62.7%, N = 550 ppm, P = 42.6 ppm, total metals = 2480 ppm, total chlorides = 31 ppm and organic chlorides = 26 ppm, were mixed with water at a ratio of 4:1 and stirred at 260°C for 3 h. The aqueous and oil phases were separated in a separatory funnel and the oil phase was filtered to remove any solids. The oil recovery was 94.9%. The oil phase was bleached with 1000 ppm CA, 1 wt-% BE Tonsil under standard bleaching conditions. The product contained 83.1% FFA and the removal rates were: total chlorides 91% (30.9 to 2.8 ppm), organic chlorides 90% (26 to 2.7 ppm), N 10% (550 to 495 ppm), P 99% (42.6 to 0.4 ppm), metals 36% (2480 to 1580 ppm). Filtration resistance is 700 GPas / kg 2 .

[0149] Example 4.1

[0150] Reference bleaching of waste edible oils and fats in China.

[0151] Bleaching of Chinese waste cooking oil with citric acid (1000 ppm) + 1 wt-% of BE Tonsil reference, removal of total chloride 9% (31 to 28.1 ppm), N 13% (550 to 481 ppm), P 23% (42.6 to 32.9 ppm), metal 14% (2480 to 2135 ppm). Filtration resistance 850 GPas / kg 2 .

[0152] As is apparent from the examples shown above, the present invention provides an efficient process capable of reducing or eliminating "difficult to remove" organochlorine compounds with relatively low oil losses, i.e., a high yield of purified oil phase is obtained. At the same time, part of the glycerides are hydrolyzed to FFAs, and the amount of other impurities, such as, for example, phosphorus-containing compounds and metal-containing compounds, is reduced.

[0153] Furthermore, the filtration resistance is significantly reduced compared to the bleaching of the reference or the bleaching of the reference thermally treated product.

Claims

1. A method for purifying a raw material, the method comprising the following steps; a) provide raw materials, b) mixing or contacting the raw material with water, c) heating the feedstock / water mixture obtained in b), d) separating the aqueous phase and the oil phase obtained in step c), e) removing solids from said oil phase obtained from step d), To obtain an oil phase substantially free of or with a reduced amount of chlorine-containing compounds.

2. The method according to claim 1, wherein: The feedstock is characterized as a low quality feedstock having a chloride content of about 50 ppm or more, such as, for example, about 75 ppm or more, such as, for example, about 100 ppm or more, such as, for example, about 125 ppm or more, such as, for example, about 150 ppm or more, such as, for example, about 175 ppm or more, such as, for example, about 200 ppm or more, such as, for example, about 225 ppm or more.

3. The method according to any one of claims 1 to 2, wherein: The raw materials are waste cooking grease, grease trap grease and brown grease, low quality waste cooking oil (UCO), low quality animal fat or any mixture thereof.

4. A method according to any one of the preceding claims, wherein: The usage ratio (w / w) of the raw material to water is about 1:1, such as, for example, about 2:1, such as, for example, about 3:1, such as, for example, about 4:1, such as, for example, about 5:1, such as, for example, about 6:1, such as, for example, about 7:1, such as, for example, about 8:1, such as, for example, about 9:1, such as, for example, about 10:1, etc.

5. A method according to any one of the preceding claims, wherein: The heating in step c) is at a temperature in the range of about 200°C to about 300°C, such as for example about 210°C, such as for example about 220°C, such as for example about 230°C, such as for example about 240°C, such as for example about 250°C, such as for example about 260°C, such as for example about 270°C, such as for example about 280°C, such as for example about 290°C.

6. A method according to any one of the preceding claims, wherein: The heating in step c) is carried out for a time period of about 1 minute to about 60 minutes, or 1 h to about 6 h, such as for example about 2 h, such as for example about 3 h, such as for example about 4 h, such as for example about 5 h, or alternatively at least 1 minute, such as for example at least about 5 minutes, at least about 10 minutes, at least about 15 minutes, at least about 20 minutes, at least about 15 minutes, at least about 20 minutes, at least about 25 minutes, at least about 30 minutes, at least about 35 minutes, at least about 40 minutes, at least about 45 minutes, at least about 50 minutes, at least about 55 minutes, at least about 50 minutes.

7. A method according to any one of the preceding claims, wherein: The heating in step c) results in partial hydrolysis of triglycerides present in the feedstock into free fatty acids and di- and / or monoglycerides.

8. A method according to any one of the preceding claims, wherein: Separation of the aqueous phase from the oil phase obtained in step c) is achieved by centrifugation, spontaneous phase separation, sedimentation, decantation, evaporation of water, or any combination thereof.

9. A method according to any one of the preceding claims, wherein: The oily phase collected from the phase separation in step d) is subjected to any type of filtration in order to remove any solid material present in said oily phase.

10. A method according to any one of the preceding claims, wherein: The process may optionally comprise a bleaching step after step e).

11. A method according to any one of the preceding claims, wherein: The bleaching step comprises treating the oil phase with citric acid and / or bleaching earth.

12. A method according to any one of the preceding claims, wherein: At least about 90% of the oil present in the feedstock is recovered, such as, for example, about 95%, such as, for example, about 98%, or such as, for example, about 99%.

13. A method according to any one of the preceding claims, wherein: The chloride content of the resulting oil phase obtained from the process is reduced by about 85% or more, such as for example about 90% or more, such as for example about 95% or more, such as for example about 98% or more, relative to the feedstock provided in a).

14. A method according to any one of the preceding claims, wherein: Relative to the feedstock provided in a), the phosphorus and / or metal content of the resulting oil phase obtained from the process is reduced by about 70% or more, such as, for example, about 80%, such as, for example, about 85% or more, such as, for example, about 90% or more, such as, for example, about 95% or more, such as, for example, about 98% or more.

15. A method according to any one of the preceding claims, wherein: Filtration resistance is less than about 1800 GPas / kg 2 , such as 1700 GPas / kg 2 or less, such as, for example, 1500 GPas / kg 2 or less, such as 1300 GPas / kg 2 or less, such as 1000 GPas / kg 2 or less, such as 750 GPas / kg 2 or less, such as 600 GPas / kg 2 or less, or such as 400GPas / kg 2 or less.

16. A purified oil phase obtainable by the process according to any one of claims 1 to 15.

17. An oil phase comprising: a) less than about 9 ppm total chloride content, b) a phosphorus content of less than about 2 ppm, c) a metal content of less than about 250 ppm.