Removal of impurities from tall oil feed by solvent precipitation

Abstract

There is provided a process for purifying impurities from a tall oil feed, and a corresponding liquid product obtained by the process, the process comprising mixing the tall oil feed with an added solvent, removing the impurities precipitated upon addition of the solvent, and then recovering the liquid product as a tall oil feed having a reduced impurity content.

Description

Technical Field

[0001] The present disclosure generally relates to the processing of tall oil feedstock. The present disclosure particularly, but not exclusively, relates to a method of removing impurities from a tall oil feedstock by solvent precipitation to obtain a purified tall oil feedstock. Background Art

[0002] This section provides useful background information but does not constitute an admission that any of the techniques described herein represent the state of the art.

[0003] Tall oil feeds, such as crude tall oil (CTO) and its derivatives, such as tall oil pitch (TOP), crude fatty acids (CFA), tall oil fatty acids (TOFA), and distilled tall oil (DTO), contain various impurities that are generally detrimental to tall oil feeds. These impurities are typically metals (including sodium, potassium, and iron), metalloids (silicon), and non-metals (phosphorus, nitrogen, sulfur, and chlorine), which make it difficult and costly to utilize tall oil feeds in the chemical industry.

[0004] Therefore, there is a need to develop purification methods that at least partially alleviate the above problems. In addition, there is a need for renewable carbonaceous products that can be further converted into fuels and / or used in the chemical industry. Summary of the invention

[0005] The attached claims define the scope of protection. Any examples or descriptions of devices, systems, products or processes in the specification, claims and / or drawings that are not covered by the claims are not presented herein as embodiments of the present invention, but are presented as background technology or as examples for understanding the present invention.

[0006] According to a first aspect, there is provided a method for removing impurities from a tall oil feed, the method comprising:

[0007] a. adding a solvent comprising C3-C18 paraffins, preferably C3-C7 paraffins, to the tall oil feed to obtain a mixture, and

[0008] b. a separation step comprising separating at least one solid precipitate and a liquid phase from the mixture;

[0009] And wherein the method further comprises bleaching at least one of the tall oil feed, the mixture, and the liquid phase.

[0010] In the process of the present invention, a solvent is added to a tall oil feed to provide a mixture, which forms a precipitate containing impurities. The precipitate and the impurities contained therein are then separated from the mixture to provide a purified tall oil feed as a liquid phase. Separation of the solid precipitate can be achieved, for example, by filtration. Therefore, the process of the present invention is easy to implement on an industrial scale and is suitable for integration into existing production processes.

[0011] The process of the present invention prevents or at least reduces the need for pre-treatment of the tall oil feed, such as heat treatment and / or bleaching, which are energy intensive processes and involve the use of large amounts of reagents. The process of the present invention can also reduce the amount of bleaching agents used in bleaching.

[0012] The solvent of the present invention is inert in the process and is not significantly consumed. In one embodiment, the solvent is recycled in the process. The solvent can be separated from the purified tall oil feed or the liquid phase by distillation. Solvents containing C3-C7 paraffins are preferred because they are more easily separated in step b or from the liquid phase.

[0013] Another advantage of the process of the present invention is that the life of the catalyst in the downstream processing of the purified tall oil feed is extended when the impurities are removed. Advantageously, the process of the present invention is able to remove impurities that would otherwise inhibit or deactivate catalysts commonly used for chemical conversion of tall oil feeds.

[0014] Another advantage is that water used in previous purification processes can be avoided, providing environmental benefits in terms of reduced wastewater generation. This also makes the present invention suitable for removing water-soluble impurities, making tall oil feed sources more diverse.

[0015] The impurities purified by the process of the present invention are precipitated as a solid precipitate.

[0016] The method of the present invention is particularly effective in removing elemental impurities. Elemental impurities are elements that are problematic for the function and life of the catalyst and can also increase the fouling of the process. An example of an elemental impurity is a metallic impurity. Another example of an elemental impurity is a metalloid impurity. Other examples of elemental impurities are the elements shown in Table 1 and / or Table 2. Another impurity removed by the method of the present invention is lignin.

[0017] In one embodiment, the method of the present invention further comprises hydrodeoxygenating the liquid phase obtained in step b to obtain a hydrodeoxygenated product, and recycling the hydrodeoxygenated product at least partially to step a, wherein the temperature during step a does not exceed 100° C. It is preferred to keep the temperature below 150° C. and / or below 100° C. to at least partially prevent the formation of agglomerates.

[0018] In one embodiment of the process of the present invention, the tall oil feed comprises at least one of crude tall oil (CTO) and its derivatives such as tall oil pitch (TOP), crude fatty acids (CFA), tall oil fatty acids (TOFA) and distilled tall oil. In one embodiment of the process of the present invention, the tall oil feed comprises at least one of crude tall oil (CTO) and tall oil pitch (TOP). In another embodiment, the tall oil feed is crude tall oil, tall oil pitch or a mixture thereof.

[0019] In one embodiment, the tall oil feed contains less than 25 wt%, less than 24 wt%, less than 23 wt%, less than 22 wt%, less than 21 wt%, or less than 20 wt% fatty acids. In another embodiment, the tall oil feed contains less than 22 wt%, less than 20 wt%, less than 18 wt%, less than 16 wt%, less than 14 wt%, less than 12 wt%, or less than 10 wt% fatty acids.

[0020] In one embodiment, the tall oil feed contains no animal fat.

[0021] Crude tall oil (CTO) is usually obtained as a by-product of the kraft process (wood pulping). CTO contains resin acids, fatty acids and unsaponifiables. Resin acids are a mixture of organic acids derived from the oxidation and polymerization of terpenes. Fatty acids are long-chain monocarboxylic acids found in hardwoods and softwoods. Unsaponifiables cannot be converted into soaps because they are neutral compounds that do not react with sodium hydroxide to form salts.

[0022] The term "tall oil pitch (TOP)" refers to the residual bottom fraction from the crude tall oil (CTO) distillation process. Tall oil pitch typically contains 34-51 wt% free organic acids, 23-37 wt% esterified organic acids and 25-34 wt% unsaponifiable neutral compounds, based on the total weight of the tall oil pitch. The organic acids (free and esterified) are typically carboxylic acids, primarily fatty acids and rosin acids.

[0023] The term "crude fatty acids (CFA)" refers to fatty acid-containing materials obtainable by purification (eg, vacuum distillation, extraction, and / or crystallization) of CTO.

[0024] The term "tall oil fatty acids (TOFA)" refers to the fatty acid-rich fraction of the crude tall oil (CTO) distillation process. TOFA typically comprises mainly fatty acids, which typically account for at least 80% by weight of the total weight of TOFA. Typically, TOFA comprises less than 20% by weight of rosin acids.

[0025] The term "distilled tall oil (DTO)" refers to the resin acid-rich fraction of the crude tall oil (CTO) distillation process. DTO generally contains mainly fatty acids and rosin acids, with fatty acids generally accounting for 55-90% by weight of the total weight of DTO and rosin acids generally accounting for 10-40% by weight of the total weight of DTO. Typically, DTO contains less than 10% by weight of unsaponifiable neutral compounds, based on the total weight of distilled tall oil.

[0026] In one embodiment of the process of the present invention, the mass ratio of tall oil feed to added solvent is selected from the range of 1:2 to 2:1, or 1:2 to 1:1, or 1:1 to 1:2. In another embodiment, the mass ratio of tall oil feed to added solvent is selected from the range of 1:3 to 3:1, or 1:3 to 2:1, or 1:3 to 1:1, or 1:3 to 1:2, or 3:1 to 2:1, 3:1 to 1:1, or 3:3 to 1:2, or 3:3 to 1:3. For the same mass of tall oil feed, it is preferred to use less solvent to achieve a lower total flow rate. In addition, a lower amount of solvent may mean a higher viscosity of the mixture, while a higher amount of solvent can be used to reduce the viscosity of the mixture.

[0027] In one embodiment, the process of the present invention is a continuous process, which further comprises recovering C3-C18 hydrocarbons, preferably C3-C7 hydrocarbons, from the liquid phase and recycling them at least partially in the solvent added in step a. Advantageously, when the process is operated as a continuous process, the solvent required for purification can be produced by the process itself, so when the process is operated in a continuous mode, no additional solvent needs to be fed into the process. In another embodiment, a solvent containing C3-C18 and / or C3-C7 hydrocarbons is added to the continuous process, at least at the beginning of the continuous process. Recycling of the solvent allows the amount of tall oil feed fed into the added solvent to be controlled, so that the purification process can be easily adjusted for tall oil feeds containing different impurities.

[0028] In one embodiment, the method of the present invention is a continuous process comprising hydrodeoxygenating the liquid phase obtained in step b to obtain a hydrodeoxygenated product, recovering C3-C18 hydrocarbons, preferably C3-C7 hydrocarbons, from the hydrodeoxygenated product and recycling them at least partially to step a.

[0029] In one embodiment, the process of the invention is carried out such that during step a or b, and optionally during bleaching, the temperature does not exceed 100°C.

[0030] In one embodiment, the process of the invention is carried out so that during step a or b, and optionally during bleaching, the temperature does not exceed 50° C. This embodiment is useful when no recycled HDO product is used. In this case, the high impurity tall oil feed can be mixed directly with the solvent.

[0031] In one embodiment of the process of the invention, bleaching comprises bleaching with an acid, preferably bleaching the liquid phase with an acid solution and an adsorbent such as a bleaching earth, for example bentonite or a bleaching clay, for example hydrated aluminium silicate.

[0032] The term "acid" is intended to mean any type of acid or a substance that is chemically classified as an acid. The acid can be an organic acid or an inorganic acid. The acid can also be a monoacid, a diacid, a triacid, or a tetraacid having one or more acid functional groups. Some non-limiting examples can be, for example, citric acid, oxalic acid, malic acid, malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, ethylenediaminetetraacetic acid (EDTA), phosphoric acid, sulfuric acid, etc., in any suitable concentration.

[0033] In one embodiment of the method of the present invention, the solid precipitate is further washed with the solvent used in step a, preferably with a C3-C7 paraffin, more preferably with pentane. By this embodiment, oil loss can be at least partially prevented, thereby resulting in a higher carbon efficiency of the method.

[0034] In the embodiment of washing the solid precipitate with the solvent used in step a, washing means washing with a paraffin mixture containing the same hydrocarbon as the solvent. For example, when the solvent contains C3-C18 or C3-C7 paraffins, the solid precipitate is washed with C3-C18 or C3-7 paraffins, respectively. It is clear to the technician that when referring to the solvent used in step a, this means that the paraffin composition of the solvent used during washing is similar to that of the paraffin mixture of paraffins. For example, when the solvent is at least partially recycled after hydrodeoxygenation and used as a solvent in step a, this recycled solvent can be used to wash the solid precipitate. However, the technician understands that in the method of the present invention, it is not necessary to directly obtain the solvent for washing the precipitate, and a hydrocarbon mixture having the same or similar carbon number composition as the solvent can also be used instead. However, preferably, the carbon number distribution of the solvent used during washing is narrower than the carbon number distribution of the liquid product or solvent used to obtain the mixture in step a.

[0035] In one embodiment, the method of the present invention further comprises recycling the washing effluent obtained from washing with a solvent in step a. This embodiment is used to recover carbonaceous components from solid precipitates while controlling the amount of impurities in the liquid product at a low level.

[0036] In one embodiment, the method of the present invention further comprises a filtering step, wherein the mixture is filtered through a filter of about 1-10 µm, preferably about 5 µm. In one embodiment, the filtering step is used as separation step b.

[0037] Surprisingly it has been found that impurities can be removed by a filtration step, wherein the mixture obtained in step a of the process of the invention is filtered through a filter. Previously filtration of tall oil feeds has not been feasible due to their high viscosity, which makes filtration too slow for practical purposes. Attempts have been made to address this problem by increasing the temperature to better control the viscosity of the tall oil feed, but this results in an increased solubility of the impurities, which does not allow the impurities to be removed in an efficient manner.

[0038] In one embodiment, the liquid product is filtered through a filter. This embodiment is useful in situations where a higher purity liquid product containing tall oil feed is desired after removal of solid precipitates. A solvent is used in the process of the present invention to reduce the viscosity to a level that allows the liquid product to pass through the filter without raising the temperature to a level that dissolves impurities.

[0039] According to a second aspect, a liquid phase obtained by the process of the present invention is provided. The liquid product has a reduced impurity content compared to the tall oil feed fed to the process of the present invention. By the process of the present invention, the obtained liquid phase (comprising purified tall oil feed and solvent) is chemically and physically different from the tall oil feed used as starting material. As demonstrated by the results shown in the examples, the liquid phase does not contain the impurities removed with the precipitate in step b, and the impurity content is greatly reduced.

[0040] In one embodiment, the liquid phase has a metal element content that is at least 40% lower than the tall oil feed.

[0041] In one embodiment, the liquid phase has a Fe content at least 40% lower than the tall oil feed. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Some example embodiments will be described with reference to the accompanying drawings, in which:

[0043] Figure 1 A schematic diagram showing one embodiment of the process of the present invention is shown.

[0044] Figure 2 A schematic diagram of one embodiment of the process of the present invention involving a HDO step and recycling of the HDO product as solvent is shown. DETAILED DESCRIPTION

[0045] As used herein, the term "comprising" includes the broader meanings of "including," "containing," and "comprising," as well as the narrower expressions of "consisting of" and "consisting only of."

[0046] In one embodiment, the method steps are performed in the order identified in any aspect, embodiment or claim. In another embodiment, any method step specified to be performed on a product or intermediate obtained in a previous step is performed directly on said product or intermediate, i.e. without additional, optional or auxiliary processing steps that may chemically and / or physically change the product or intermediate between the two consecutive steps.

[0047] In one embodiment, the process of the invention is an industrial process.In another embodiment, an industrial process may exclude small scale processes, such as laboratory scale processes that are not scaled up to volumes used in industry.

[0048] In one embodiment, the process of the invention is a continuous process.

[0049] In one embodiment, the boiling point refers to the boiling point at atmospheric pressure.

[0050] In one embodiment, the pressure and temperature used in the process of the invention are selected so that at least the solvent remains in liquid phase during the process, thereby excluding the optional distillation step to separate the solvent (for recycling in the process or for other purposes).

[0051] In one embodiment, the pressure is selected from the range 1-50 bar.

[0052] In one embodiment, the temperature is selected from the range 20-100°C.

[0053] In one embodiment, the temperature does not exceed 50° C. This embodiment is used to keep the solubility of impurities to a minimum.

[0054] In one embodiment, the temperature does not exceed 100° C. This embodiment is useful when the purified tall oil feed, ie the liquid phase obtained in the process of the present invention, is subjected to hydrodeoxygenation (HDO).

[0055] In one embodiment, the liquid phase is hydrodeoxygenated.

[0056] In one embodiment, the hydrodeoxygenation is preferably carried out catalytically by a NiMo catalyst, more preferably by a NiMo / CoMo catalyst, more preferably by a NiMo+alumina / CoMo+alumina catalyst.

[0057] In one embodiment, the hydrodeoxygenation is carried out at a temperature selected from the range of 290-360°C.

[0058] In one embodiment, the hydrodeoxygenation is carried out at a pressure selected from the range of 30-150 bar.

[0059] In one embodiment, the hydrodeoxygenation is carried out at a weight hourly space velocity (WHSV) of 0.1 to 3.

[0060] In one embodiment, the hydrodeoxygenation is carried out at a hydrogen to hydrocarbon volume ratio of 500-1500.

[0061] In one embodiment, the hydrodeoxygenated product has a boiling point in the range of 180-650°C.

[0062] In one embodiment, the hydrodeoxygenated product comprises 30 to 80 wt% paraffins.

[0063] In one embodiment, the hydrodeoxygenated product comprises 10-40 wt% cycloparaffins.

[0064] In one embodiment, the hydrodeoxygenated product comprises 2 to 20 wt% aromatics.

[0065] In one embodiment, the solvent comprising C3-C18 alkanes comprises each of said alkanes. The amount of a single alkane having a particular carbon number in the solvent may vary, for example, the amount of C3 alkanes (in molar, mass or volume units) is not necessarily the same as the amount of C18 alkanes in the solvent.

[0066] In one embodiment, the solvent comprises at least one alkane having a carbon number chain in the range of C3-C18. A preferred example of such a solvent is a solvent comprising or consisting of pentane. Another example is a solvent comprising pentane and at least one additional alkane having a carbon number in the range of C3-C7.

[0067] In one embodiment, the solvent comprises a C3-C7 hydrocarbon, preferably a C3-C7 paraffin. Preferably, in this embodiment, the temperature is selected from the range 20-50°C. In a more preferred embodiment, when this temperature range is used, the hydrodeoxygenation product is not recycled as solvent.

[0068] In one embodiment, the solvent comprising C3-C18 alkanes or C3-C7 alkanes comprises individual alkanes falling within this carbon number range.

[0069] The use of a solvent allows the separation of impurities from the mixture. In one embodiment, the solvent does not significantly increase the solubility of the impurities.

[0070] The solvent may be recycled in the process since the solvent hydrocarbons are compatible with downstream processing of the tall oil feed.

[0071] In one embodiment, the separation step does not involve the use of filter aids, which are typically composed of solid materials such as cellulose or chemical slurries. This has the advantage of reducing the size of the filter cake and correspondingly reducing the amount of waste. In addition, because the filter cake is smaller, washing the filter cake or solid precipitate obtained in the separation step is more efficient, resulting in a higher carbon efficiency of the process.

[0072] In one embodiment, no water is used to wash the tall oil feed in the process.

[0073] In one embodiment, the liquid phase obtained in the separation step is not washed with water.

[0074] The term purified tall oil feed refers herein to the product obtained by the process of the present invention after impurities have been removed from the tall oil feed. The purified tall oil feed is also referred to as liquid phase.

[0075] Any, some or each of the products specified in the method of the present invention may be subjected to a bleaching step, as also described herein. Figure 1 and Figure 2 As shown in the figure.

[0076] In one embodiment, bleaching is performed by mixing a feed containing tall oil feed with an acid such as citric acid or phosphoric acid or malic acid and bleaching earth.

[0077] In one embodiment, the tall oil feed is bleached directly prior to mixing with the solvent.

[0078] In one embodiment, a mixture obtained by mixing tall oil feed with a solvent is bleached.

[0079] In one embodiment, the liquid phase is bleached.

[0080] As shown in the following examples, the process of the present invention effectively removes impurities from tall oil feed. The removal of impurities was confirmed by chemical analysis, which showed that at least 40% of the impurities were successfully removed. In the context of impurities in tall oil feed, all percentage values ​​refer to weight %, and the impurities of tall oil feed are usually expressed in mg / kg.

[0081] In one embodiment, the process of the present invention removes at least 30 wt. % of the tall oil feed impurities from the tall oil feed.

[0082] In one embodiment, the process of the present invention removes at least 40 wt% of the tall oil feed impurities from the tall oil feed.

[0083] In one embodiment, the process of the present invention removes at least 30 wt. % or at least 40 wt. % of the metal impurities from the tall oil feed.

[0084] In one embodiment, the process of the present invention removes at least 30 wt. % or at least 40 wt. % of the metalloid impurities from the tall oil feed.

[0085] In one embodiment, the process of the present invention removes at least 30 wt% or at least 40 wt% of the inorganic impurities from the tall oil feed.

[0086] In an embodiment, the tall oil feed impurities include at least one of Fe, Na, P, Si, Ca, K, Al, Mn, and Mg.

[0087] In an embodiment, the tall oil feed impurities include Fe, Na, Al, Mn, and Mg, and at least 40 wt%, at least 50 wt%, at least 60 wt%, at least 70 wt%, at least 80 wt%, or at least 90 wt% of these impurities are removed by the process of the present invention.

[0088] In one embodiment, tall oil feed impurities include Fe, P and Si. At least 30 wt% or at least 40 wt% or at least 45 wt% of these impurities may be removed by the process of the present invention.

[0089] In one embodiment, lignin and / or organic salts are at least partially removed during the process of the invention.

[0090] In one embodiment, the tall oil feed impurities removed by the method of the present invention include at least one of aluminum, arsenic, barium, boron, cadmium, calcium, chromium, cobalt, iron, lithium, manganese, molybdenum, nickel, phosphorus, potassium, silicon, sodium, titanium and vanadium. In another embodiment, the impurities include each of the above elements, and at least 30 weight percent, at least 40 weight percent, or at least 45 weight percent of these elements are removed by the method of the present invention.

[0091] As shown in Example 1 below, the process of the present invention is able to reduce the amount of elemental impurities to a level of about 10 mg / kg. Prior to mixing with the solvent, the tall oil feed was bleached and contained about 21 mg / kg of elemental impurities. In one embodiment, the process of the present invention is used to remove the elemental impurities specified in Table 1.

[0092] In one embodiment, the tall oil feed impurities removed by the method of the present invention include at least one of Na, P, Si, Ca, Fe, K, Al, Mn, Zn, Mg, V, Cr, B, Mo, Ba, Ni, Cu and Ti. In another embodiment, the impurities include each of the above elements, and at least 30 wt%, at least 35 wt%, or at least 40 wt% of these elements are removed by the method of the present invention.

[0093] As shown in Example 2 below, the process of the present invention is able to reduce the amount of elemental impurities to a level of about 50-60 mg / kg. Tall oil feed contains about 335 mg / kg of elemental impurities. In one embodiment, the process of the present invention is used to remove the elemental impurities specified in Table 2.

[0094] In one embodiment, lignin and its derivatives form a precipitate that is removed in step b. Removing lignin has the advantage of reducing the amount of aromatics that may be difficult to remove in downstream processing. By removing lignin, the formation of phenolic compounds that are problematic in wastewater treatment can be reduced. In addition, in the downstream processing of the purified tall oil feed, the risk of blockage associated with lignin precipitation can be avoided.

[0095] In one embodiment, at least 50 wt. %, preferably at least 60 wt. %, more preferably at least 70 wt. %, even more preferably at least 80 wt. % of the metals and metalloids are removed in the process of the present invention.

[0096] In another embodiment, the tall oil feed comprises a pretreated, such as heat treated, bleached and / or flashed tall oil feed, and the process of the present invention removes at least 30 wt%, at least 35 wt%, at least 40 wt%, or at least 45 wt% of the remaining metals and metalloids.

[0097] Example

[0098] The following examples are provided to better illustrate the claimed invention. They should not be construed as limiting the scope of the invention, which is determined by the claims. To the extent that specific materials are mentioned, it is for illustrative purposes only and is not intended to limit the invention. Those skilled in the art can develop equivalent means or reactants without exercising inventive abilities and without departing from the scope of the invention. It should be understood that many changes can be made in the procedures described herein while still within the scope of the invention. All exemplary materials and parameters used in the following examples are compatible with the methods and products of the present invention.

[0099] Example 1: Removal of impurities from pre-treated CTO

[0100] Pretreated (including bleaching) CTO was mixed with n-pentane in a ratio of 1:2 (CTO:n-C5) at 25°C. The blend was mixed and the mixture was allowed to stand overnight. The mixture was then filtered. The filtrate was separated at 100°C with a 50 mbar vacuum to separate CTO from n-pentane. The n-pentane purity was over 99% and could be reused. The CTO mass loss (precipitate) was about 0.7-1.7 wt%. The precipitate contained 40-50% lignin, 1-10% esters, 15-25% fatty acids and 20-30% resin acids. CTO from which the precipitate was separated by solvent extraction contained about half of the original metals and metalloids (see Table 1).

[0101] Table 1. Removal of elemental impurities from pre-bleached CTO. Purified CTO refers to the amount obtained by the process of the present invention.

[0102]

[0103] Example 2: Removal of impurities from untreated CTO

[0104] Untreated CTO was mixed with n-pentane at a ratio of 1:2, 1:1 or 2:1 (CTO:n-c5) at 25°C. The blend was mixed and allowed to stand overnight. The mixture was filtered. The filtrate was evaporated at 60°C. The CTO mass loss (precipitate) was about 0.6-2.0 wt%. The precipitate consisted of about 0.08-0.6 wt% metals and metalloids. About 82-87% of the metals and metalloids were removed from the CTO (see Table 2).

[0105] Table 2. Removal of elemental impurities from unbleached CTO at different solvent ratios (expressed as mass / mass ratio).

[0106]

Claims

1. A method for removing impurities from a tall oil feed, comprising: a. adding a solvent comprising C3-C18 paraffins to the tall oil feed to obtain a mixture, and b. a separation step, the separation step comprising separating at least one solid precipitate and a liquid phase from the mixture; And wherein the method further comprises bleaching at least one of the tall oil feed, the mixture and the liquid phase.

2. The method according to claim 1, wherein the method further comprises hydrodeoxygenating the liquid phase obtained in step b to obtain a hydrodeoxygenated product, and recycling at least part of the hydrodeoxygenated product to step a, and wherein the temperature during step a does not exceed 100°C.

3. The method according to claim 1 or 2, wherein the tall oil feed comprises at least one of crude tall oil (CTO), tall oil pitch (TOP), crude fatty acid (CFA), tall oil fatty acid (TOFA) and distilled tall oil (DTO).

4. The method of claim 1 or 2, wherein the tall oil feed comprises at least one of crude tall oil (CTO) and tall oil pitch (TOP).

5. The process according to any one of claims 1 to 4, wherein the mass ratio of the tall oil feed to the added solvent is selected from the range of 1:2 to 2:

1.

6. The process according to any one of claims 1 to 5, wherein the process is a continuous process, further comprising recovering C3-C18 hydrocarbons, preferably C3-C7 hydrocarbons, from the liquid phase and recycling them at least partially in the solvent added in step a.

7. The process according to any one of claims 1 to 6, wherein the process is carried out such that during step a or b, and optionally during the bleaching, the temperature does not exceed 100°C.

8. The method according to any one of claims 1 to 7, wherein the bleaching comprises bleaching with an acid, preferably bleaching the liquid phase with an acid.

9. The process according to any one of claims 1 to 8, wherein the solid precipitate is washed with the solvent used in step a, preferably with a C3-C7 hydrocarbon, more preferably with pentane.

10. The method according to claim 9, further comprising recycling the wash effluent obtained from the washing in step a.

11. The method according to any one of claims 1 to 10, further comprising a filtering step, wherein the mixture is filtered through an approximately 1-10 µm filter, preferably an approximately 5 µm filter.

12. Liquid phase obtained by the process according to any one of claims 1 to 11.

13. The liquid phase of claim 11, having a metal element content at least 40% lower than that of the tall oil feed.

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