Title - PROCESS FOR THE PRODUCTION OF PURIFIED BIODIESEL FROM A RAW MATERIAL CONTAINING AN UNSAPONIFIABLE MATERIAL AND PROCESS FOR THE RECOVERY OF A VALUABLE CHEMICAL WHILE PRODUCING PURIFIED BIODIESEL FROM A RAW MATERIAL

Abstract

A process for producing crude biodiesel from renewable feedstocks (such as fats and oils) containing unsaponifiable materials; purifying the crude biodiesel through a purification process; recovering a purified biodiesel distillate stream and a less volatile biodiesel residue stream; and further recovering valuable chemicals from the biodiesel residue. Specifically, the present technology relates to concentrating valuable chemicals in the biodiesel residue product from biodiesel production and subsequently recovering these valuable chemicals. The process may further include converting the biodiesel residue into diesel-type hydrocarbons via hydrodeoxygenation and then purifying the resulting hydrocarbon fraction.

Description

METHODS AND DEVICES FOR THE PRODUCTION OF BIODIESEL, DIESEL RANGE HYDROCARBONS AND PRODUCTS OBTAINED FROM THESE CROSS REFERENCE TO RELATED APPLICATION This application is based on U.S. provisional application serial number 62 / 666.503 filed on May 3, 2018, the full description of which is expressly incorporated herein by reference. FIELD OF INVENTION The present invention relates, in general terms, to the processing of vegetable oils and other lipid raw materials into high-quality biodiesel and simultaneously with the recovery of valuable chemical by-products. BACKGROUND For many years, valuable chemicals present in vegetable oils have been recovered for applications in the pharmaceutical, nutritional, and cosmetic industries. These valuable chemicals include sterols, steryl esters, steryl glycosides, terpenes, tocopherols, vitamins, flavonoids, carotenoids, sulfolipids, proteins, hydroxycinnamic acids, myricyl fatty acid esters, waxes, and other components present in small quantities in vegetable oils. Because most of the target valuable chemicals comprise less than 2% of the original oil, their efficient and economical isolation can be challenging. Over the past 50 years, two primary commercial sources of these plant chemicals have emerged: one from the refining of vegetable oil and a second from production from Tall Oil. 238882 1944035 of 44 In vegetable oil refining, various processing stages are used to remove impurities from crude oil, including degumming, chemical refining, bleaching, and deodorization. During degumming, an acidic solution is mixed with crude oil to hydrate the gums. In chemical refining, a basic solution is mixed with the crude oil to react with the free fatty acids and form soapstock. Both the soapstock and the hydrated gums are removed from the crude oil by centrifugation. The crude oil is then further refined in bleaching and deodorization stages, where sterols and tocopherols are also removed. Deodorization of the crude oil is carried out under high vacuum (1–8 mbar) and a temperature of 180–270 °C.After deodorization, the crude oil is significantly free of impurities, contains mostly triglycerides, and is processed into a fully refined oil. The volatiles from deodorization are condensed into a deodorizing distillate containing free fatty acids, unsaponifiables, and monoglycerides. The unsaponifiables consist mainly of tocopherols, sterols, terpenes, and steryl esters. The second commercial source of valuable chemicals is Tall Oil from the pulp and paper industry. In the Kraft pulping or sulfate pulping process, wood chips are cooked in a mixture of sodium sulfide and sodium hydroxide. These chemicals dissolve the lignin and some of the hemicellulose left behind in the cellulose fibers. Once the wood pulp is removed, the remaining liquid, called black liquor, contains lignin fragments, carbohydrates from the breakdown of cellulose, sodium carbonate, sodium sulfate, and inorganic salts. The black liquor is heated to evaporate concentrated liquids and solids. During this process, the alkaline mixture reacts with the fatty and resin acids in the black liquor, forming a rosin soap that rises to the top and is skimmed off. The skimmed-off material is known as Tall Oil soap.Tall oil soap is then acidified with a mineral acid, producing an aqueous phase and an oily phase (crude tall oil). Crude tall oil contains unsaponifiables, free fatty acids, and resin acids. The unsaponifiables are composed of varying concentrations of waxes, alcohols, fatty acid esters, sterols, and steryl esters. At this time, the recovery of valuable chemicals is largely the same 238882 1944035 of 44 for both the deodorant distillate from vegetable oil refining and the crude Tall Oil from Kraft's pulping processes. In both cases, the valuable chemicals are further concentrated into the unsaponifiables by distillation and / or various chemical reactions, including hydrolysis, esterification, saponification, acidulation, and physical separations such as filtration and solvent extraction. For example, U.S. Patent 2,263,550 describes a process for separating unsaponifiable matter from crude fats and oils for the production of vitamin E (tocopherol) and sterols. The invention aims to accomplish this by converting glycerides in the raw material to esters with the addition of an alcohol. Esters have a lower boiling point than the original glycerides and can therefore be removed by distillation. The remaining residue containing vitamin E is concentrated by saponification with alkalis and finally extracted with ether, chloroform, ethylene dichloride, or other suitable solvents. In U.S. Patent 3,335,154, Smith describes a process for separating tocopherols and sterols from deodorant distillate. The deodorant distillate undergoes a saponification reaction to remove fatty acid esters. The distillate is then acidified, producing a mixture of free fatty acids, free tocopherols, free sterols, glycerol, water, excess mineral acid, and alkaline salts. The glycerol, water, and excess acid are removed by phase separation, and the oily phase is then esterified with an alcohol and an acid catalyst. At this point, cold water is added to the mixture to crystallize the sterols, which are subsequently removed by filtration. Finally, the filter cake is rinsed with acetone and an alcohol solvent, yielding a crystalline sterol product. The resulting filtrate is then heated to remove the acetone and alcohol, leaving a concentrated tocopherol residue. In U.S. patent 5,487,817, Fizet describes another process for recovering tocopherols and sterols from deodorant distillate. In this process, the sterols are esterified with the fatty acids in the deodorant distillate. The resulting mixture is then distilled twice, first to remove most of the fatty acids, followed by a second distillation at a higher temperature to remove a fatty acid mixture rich in unesterified tocopherols and sterols. The steryl esters formed in the 238882 1944035 of 44 esterification reaction remains in the distillation bottoms. The distillate from the second distillation is then subjected to a second esterification reaction with methanol, which converts the fatty acids into methyl esters in the presence of an acid catalyst. The tocopherols in the second esterification product are then recovered on an ion-exchange resin by adsorption. A high-purity concentration of tocopherols is desorbed from the ion-exchange resins using mixtures of acetic acid / isopropanol and potassium hydroxide or sodium hydroxide, which also regenerates the resin. The steryl esters (and a small amount of tocopherol esters) from the first esterification reaction and the distillation bottoms are obtained by transesterification of the steryl esters (and tocopherol esters) with an alcohol and an acid catalyst. This produces sterols, tocopherols, and alkyl esters of fatty acids.The transesterification product is cooled to crystallize and filtered to recover the sterols. In U.S. patent 5,512,691, Barnicki et al. describe a process for creating a tocopherol concentrate from vegetable oil distillates. First, the distillate material is esterified so that the sterols react with the free fatty acids present in the mixture to form steryl esters, and any monoglycerides or diglycerides are converted to triglycerides with the free fatty acids. The mixture is then subjected to a series of distillation steps. One step involves the removal of unreacted free fatty acids as distillate, leaving a tocopherol-rich bottom. A second distillation removes a tocopherol-rich product as a second distillate, leaving steryl esters and glycerides as a second bottom product. And in U.S. patent 6,846,941, Rohr et al. describe a process for separating unsaponifiable products from animal and vegetable raw materials. The unsaponifiable material is first obtained by saponifying the raw material into zinc, iron, manganese, magnesium, calcium, copper, lead, cobalt, or aluminum soaps, which have a lower melting point than potassium or sodium soaps. These soaps can be formed directly by saponification or by converting potassium and sodium soaps to the lower-melting-point soaps through ion exchange. After the lower-melting-point soaps are dried, they undergo a series of distillation steps to obtain the desired purity of unsaponifiable material, either as a distillate or 238882 1944035 of 44 as residue (distillation bottoms). Additional techniques such as chromatography, filtration, and crystallization can also be used to improve the purity of the unsaponifiable products. One of the challenges in obtaining valuable chemicals from unsaponifiable material, whether from vegetable oil refining or Kraft pulping processes, is that these valuable chemicals are present as minor components in byproduct streams from each process that contain significant impurities. Therefore, expensive equipment and complex refining processes are needed to yield products pure enough to justify further processing. While it is technically possible to obtain valuable chemicals from unsaponifiable material in deodorant distillates and crude tall oil, the commercial value of the relatively small quantity of end products obtained does not always justify the commercial-scale implementation of the equipment and processing required for their purification. Therefore, the availability of valuable chemicals, including sterols, steryl esters, steryl glycosides, terpenes, tocopherols, vitamins, flavonoids, carotenoids, sulfolipids, proteins, hydroxycinnamic acids, myricyl esters of fatty acids, waxes, and other components, has been limited. Simultaneously, as the biodiesel industry has grown, quality specifications for biodiesel have become more stringent than early production process designers anticipated, and the biodiesel market has become more competitive. As a result, biodiesel producers have an urgent need to improve the economics of their production processes to remain economically viable, either by using new and / or lower-cost feedstocks or by enhancing the value of their co-products, or preferably both. However, low-cost feedstocks often contain unsaponifiable material that can impair biodiesel quality according to commercial biodiesel specifications, including ASTM D6751-18, CAN / CGSB 3.524, and various customer-specific specifications.What the industry needs are methods that produce not only quality biodiesel that meets increasingly demanding commercial expectations but also valuable co-products that can boost the increasingly demanding economics of production. 238882 1944035 of 44 biodiesel. Therefore, there is a need for an invention that overcomes the exhaustive economic and processing limitations that previously prevented the commercial-scale production of large quantities of valuable chemicals present in unsaponifiable materials in fats and oils by combining aspects of high-purity biodiesel production with commercial-scale processes for the production of such valuable chemicals. Additional information regarding the biodiesel production processes is described in the applicant's prior U.S. patent number 9,957,464, issued May 1, 2018, which is incorporated herein in its entirety by this reference. COMPENDIUM One aspect of the invention relates to a process for producing purified biodiesel from a feedstock containing unsaponifiable material. The process includes introducing the feedstock into a pretreatment process to create a pretreated feedstock, then reacting the pretreated feedstock in a transesterification reactor with an alcohol to produce crude biodiesel. The crude biodiesel is separated (purified) to produce a biodiesel residue comprising unsaponifiable material and purified biodiesel. In some embodiments, the separation step may include the use of at least one of the following: cold filtration, membrane filtration, and resin filtration. In some embodiments, the separation step may include distillation to produce purified biodiesel and distillation bottoms comprising unsaponifiable material.At least some of the unsaponifiable material is recovered. The unsaponifiable materials are recovered by solvent extraction. The unsaponifiable material may include at least one of the following valuable chemicals: sterols, steryl esters, steryl glycosides, terpenes, tocopherols, vitamins, myricyl esters of fatty acids, sulfolipids, proteins, hydroxycinnamic acids, waxes, flavonoids, and carotenoids. The process may further include the removal of at least one of the valuable chemicals from the unsaponifiable material using at least one of the following methods: saponification, transesterification, esterification, hydrolysis, and solvent separation. 238882 1944035 of 44 Another aspect of the invention relates to a process for producing hydrocarbons from biological feedstock. The process includes diluting the biological feedstock with a hydrocarbon oil to produce a dilute biological feedstock, which is then subjected to a hydrodeoxygenation process by contacting it with a hydrogen-rich gas and a catalyst at elevated temperature and pressure to produce a reactor effluent. The reactor effluent is cooled to produce a cold reactor effluent, from which a hydrocarbon fraction is then recovered. The biological feedstock comprises free fatty acids, fatty acid glyceride esters, and unsaponifiable material at concentrations greater than 2% by weight.In some embodiments, the biological feedstock comprises biodiesel residue such as distillation bottoms recovered from a biodiesel distillation process. In some embodiments, the cold reactor effluent is separated into a hydrocarbon phase, a gas phase, and an aqueous phase. In some embodiments, a hydrocarbon separator is used to separate the hydrocarbon phase into a main fraction and a hydrocarbon fraction. The hydrocarbon fraction can be added to diesel fuel. In some embodiments, the hydrocarbon fraction is further fed into at least one hydrocracking and hydroisomerization process to produce a renewable diesel fuel. BRIEF DESCRIPTION OF THE FIGURES The advantages of the described technology can be better understood by referring to the descriptions below and the accompanying figures. The figures are not to scale and represent illustrative configurations showing the general principles of the technology; they are not intended to limit the scope of the invention. The dotted lines in the figures represent the different embodiments that can be included as part of the process in some embodiments. FIG. 1 is a process flow diagram showing various methods for producing biodiesel and valuable chemicals from raw materials. FIG. 2 is a process flow diagram showing more modalities 238882 1944035 of 44 specific for the production of biodiesel and valuable chemicals from raw materials shown in FIG. 1. FIG. 3 is a process flow diagram showing modalities that include a hydrodeoxygenation reactor system. FIG. 4 is a graphical representation of the effect of hydrodeoxygenation on the concentration of components at over 400 °C (as measured by ASTM D288718), present in a biological raw material. DETAILED DESCRIPTION The apparatus, devices, systems, products, and methods of the present invention will be described in detail below by reference to various non-exhaustive modalities, including figures, which are merely illustrative. Unless otherwise stated, all numbers expressing dimensions, capacities, and the like used in the specification and claims shall be understood to be modified by the expression "around". If any use of the expression is unclear to those skilled in the art due to the context in which it is used, "around" shall mean up to plus or minus 10% of the particular expression. The present invention may be implemented by carrying out process steps in orders different from those specifically stated herein. All references to "step" may include multiple steps (or substeps) within the meaning of one step. Likewise, all references to "steps" in the plural may also be interpreted as a single process step or various combinations of steps. The present invention can be implemented by carrying out process units in orders different from those specifically stated herein. All references to "unit" may include multiple units (or subunits) within the meaning of one unit. Likewise, all references to "units" in the plural may also be interpreted as a single process unit or various combinations of units. 238882 1944035 of 44 As used in this specification and in the accompanying claims, the singular forms "a / an" and "the" include plural referents, unless the context clearly indicates otherwise. As used in this specification and accompanying claims, the term "fats and oils" refers to any material of biological origin, whether animal or vegetable, that is useful as a feedstock for the production of biodiesel. The feedstock may be in its raw state, containing impurities, and is considered "raw feedstock" or "raw oil." Alternatively, the feedstock may be pre-treated using other equipment to remove impurities. The pre-treatment process may take place at a biodiesel production facility, at the source site, or both, resulting in "pre-treated feedstock" or "pre-treated oil." The term "refined raw material" refers to raw materials that have a sufficiently low content of free fatty acids to be used directly in transesterification. Refined raw materials may include crude alkyl esters. The term "free fatty acids" refers to aliphatic carboxylic acids with carbon chains of approximately 6 to 24 carbon atoms. Free fatty acids (FFAs) can be found in fats and oils at concentrations between 0 and 100% by weight and are susceptible to esterification after reaction with an alcohol under esterification conditions. The term "ester" is used to refer to organic esters in which a fatty acid residue is joined to an alcohol residue by an ester bond, including monoesters, diesters, triesters and more generally, multiesters. The term "biodiesel" is used to describe a fuel comprising fatty acid alkyl esters (FAAEs) of long-chain fatty acids, derived from fats and oils. "Biodiesel," as used herein, may also contain a minority of "impurities" or compounds other than FAAEs. The term "biodiesel residue" is used to refer to the portion of crude biodiesel that is removed when the crude biodiesel is converted into purified biodiesel. 238882 1944035 of 44 The expression "distillation bottoms" is used to refer to the less volatile product, or bottoms, of biodiesel distillation, where biodiesel is the intended main distillate or product. "Distillation bottoms" is the "biodiesel residue" in modalities where distillation is used to purify crude biodiesel. The term "alcohol" is used herein to refer to an organic alcohol, including monohydric alcohols, dihydric alcohols and, in general, polyhydric alcohols. The terms “wax” or “wax compounds” refer to relatively large molecules with at least one long saturated carbon chain found in oils such as corn oil, canola oil, sunflower oil, olive oil, poultry fat, sagebrush oil, and some microbial or algal oils. Wax compounds have a high melting point compared to whole oil (up to 80 °C) and can cause the oil to become cloudy upon cooling. Waxes have been grouped into the category of unsaponifiable material for the purposes of this presentation. Wax compounds can cause biodiesel to fail certain tests, even at concentrations below 0.1% by weight. The terms “unsaponifiable material” and “unsaponifiables” refer hereto to components that are naturally present in a lipid feedstock in minor quantities and are not readily converted into fatty acids and essential fatty acids (FAAEs) in a biodiesel production process. With respect to the primary product (biodiesel), unsaponifiable material may be considered impurities that can reduce the FAAE content and / or yield and / or quality of the biodiesel. Unsaponifiable material and unsaponifiables include sterols, steryl esters, steryl glycosides, terpenes, tocopherols, vitamins, myricyl esters of fatty acids, sulfolipids, proteins, waxes, flavonoids, carotenoids, hydroxycinnamic acids, and other components other than free fatty acids and glyceryl esters of fatty acids. The expression "unsaponifiable matter" refers hereto to the portion of "unsaponifiable material" that can be detected by the AOCS Ca 6a-40 test method. 238882 1944035 of 44 "Unsaponifiable matter in fats and oils," which includes sterols, steryl glycosides, terpenes, tocopherols, vitamins, flavonoids, carotenoids, and other compounds that exhibit less reactivity with strong bases. The AOCS test for unsaponifiable matter cannot quantify everything defined herein as "unsaponifiable matter." Various chemical reactions and separation techniques can be used to purify unsaponifiable material into valuable chemicals. The term "valuable chemicals" refers to purified unsaponifiable material, including sterols, steryl esters, steryl glycosides, terpenes, tocopherols, vitamins, flavonoids, carotenoids, sulfolipids, proteins, hydroxycinnamic acids, myricyl esters of fatty acids, waxes, and other components. The terms "gum" or "gums" refer to compounds (e.g., phospholipids) that may be present in a raw material and form insoluble precipitates when they come into contact with water and emulsions in basic catalytic transesterification processes. When water is added to the raw material under appropriate conditions, the gums hydrate (absorb water) and become insoluble, allowing them to be removed by a centrifugal separator. The term "acid number" refers to a common measurement of the amount of acidic functional groups in the molecules of a sample. Specifically, it refers to the amount of strong base (usually KOH) required to titrate the acidic functional groups in a sample. The acid number is conventionally expressed as milligrams of potassium hydroxide per gram of sample. The term "sulfur" refers to the total amount of sulfur in liquid fuels or raw materials defined as mg / kg or parts per million (ppm). The expression "cold immersion filtration tests" refers to test methods included in commercial specifications, such as ASTM D6751-18, CAN / CGSB 3.524 appendix A and EN 14214, that are used to evaluate the potential cold-weather performance of biodiesel and biodiesel blends. The term "paraffins," as used herein, means non-cyclic alkanes, branched or unbranched. An unbranched paraffin is an n-paraffin; a branched paraffin is an isoparaffin. 238882 1944035 of 44 The term "aromatics," as used herein, is synonymous with "aromates" and means both cyclic aromatic hydrocarbons that do not contain heteroatoms and heterocyclic aromatic compounds. The term includes monocyclic, bicyclic, and polycyclic ring systems (collectively, such bicyclic and polycyclic ring systems are referred to herein as "polycyclic aromatics" or "polycyclic aromates"). The term also includes aromatic species with alkyl and cycloalkyl groups. Aromatics thus include, but are not limited to, benzene, azulene, heptalene, phenylbenzene, indacene, fluorene, phenanthrene, triphenylene, pyrene, naphthalene, chrysene, anthracene, indene, indane, pentalene, and naphthalene, as well as alkyl- and cycloalkyl-substituted variants of these compounds.In some forms, aromatic compounds contain 6–14 carbon atoms, and in others, 6–12 or even 6–10 carbon atoms in the ring portions of the groups. The phrase includes groups containing fused rings, such as fused aliphatic and aromatic ring systems (e.g., indane, tetrahydronaphthene, and the like). "Oxygenated," as used herein, means carbon-containing compounds that have at least one covalent bond to oxygen. Examples of functional groups included by this term include, but are not limited to, carboxylic acids, carboxylates, acid anhydrides, aldehydes, esters, ethers, ketones, and alcohols, as well as esters of heteroatoms and anhydrides such as phosphate esters and phosphate anhydrides. Oxygenated compounds may also be oxygen-containing variants of aromatics, cycloparaffins, and paraffins, as described herein. "Hydroprocessing," as used herein, describes, but is not limited to, the various types of catalytic reactions that occur in the presence of hydrogen. Examples of the most common hydroprocessing reactions include, but are not limited to, hydrogenation, hydrodesulfurization (HDS), hydrodenitrogenation (HDN), hydrotreating (HT), hydrocracking (HC), aromatic saturation or hydrodearomatization (HDA), hydrodeoxygenation (HDO), decarboxylation (DCO), hydroisomerization (HI), hydrodewaxing (HDW), hydrodemetallization (HDM), decarbonylation, methanation, and reforming. Depending on the catalyst type, reactor configuration, reactor conditions, and feedstock composition, multiple reactions may occur. 238882 1944035 of 44 may appear that vary from purely thermal (i.e., they do not require a catalyst) to catalytic. In the case of describing the main function of a particular hydroprocessing unit, for example, an HDO reaction system, it is understood that the HDO reaction is merely one of the predominant reactions that occur and that other reactions may also take place. "Hydrotreating" (HT), as used herein, involves the removal of elements from groups 3, 5, 6, and / or 7 of the periodic table from organic compounds. Hydrotreating may also include hydrodemetallization (HDM) reactions. Hydrotreating thus involves the removal of heteroatoms such as oxygen, nitrogen, sulfur, and combinations of any two or more of these during hydroprocessing. For example, hydrodeoxygenation (HDO) is understood to mean the removal of oxygen by a catalytic hydroprocessing reaction to produce water as a byproduct; similarly, hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) describe the respective removal of the indicated elements during hydroprocessing. "Hydrocracking" (HC), as used herein, means the breaking of a carbon-carbon bond in a molecule to form at least two molecules in the presence of hydrogen. Such reactions normally undergo subsequent hydrogenation of the resulting double bond. "Hydroisomerization" (HI), as used herein, is defined as the structural rearrangement of carbon-carbon bonds in the presence of hydrogen to form an isomer. Hydrocracking is a competing reaction for most catalytic HI reactions, and the hydrocarbon reaction pathway, as a minor reaction, is understood to be included in the use of the term HI. Hydrodewaxing (HDW) is a specific form of hydrocracking and hydroisomerization designed to improve the low-temperature characteristics of a hydrocarbon fluid. "Renewable diesel" is used to describe a hydrocarbon fuel that is chemically similar to petrodiesel, but is made from fats and oils. It will be understood that if it is established that a composition includes "C x-Cy hydrocarbons" 238882 1944035 of 44 such as C7-C12 n-paraffins, this means that the composition includes one or more paraffins with a carbon number that is in the range of xa and y. "Pyrolysis," as used herein, is understood to mean the thermochemical decomposition of carbonaceous material with little or no diatomic oxygen or diatomic hydrogen present during the thermochemical reaction. The optional use of a catalyst in pyrolysis is normally called catalytic cracking, which encompasses the term pyrolysis, and should not be confused with hydrocracking. The methods of the invention can be adapted to a wide range of raw materials. In some embodiments of the invention, non-exclusive examples of raw materials are fats and oils, including coconut oil, palm oil, palm kernel oil, cottonseed oil, rapeseed oil, peanut oil, olive oil, linseed oil, babassu oil, tea tree oil, tallow tree oil, pomace oil, meadowfoam oil, chaulmoogra oil, coriander oil, canola oil, soybean oil, corn oil, camelina oil, carinata oil, castor oil, carraspique oil, lard oil, jatropha oil, sunflower oil, algae oils and other microbial oils, used cooking oils, bacon fat, prime white fat, yellow fat, brown fat, poultry fat, beef tallow, pork fat, and fish oils.Additionally, raw materials may include purified or distilled fats and oils, including fatty acid distillates such as palm fatty acid distillate and others. In some cases, distillation bottoms may be considered a raw material for the production of valuable chemicals, including crude biodiesel distillation bottoms. The raw materials (105) containing various impurities require pretreatment and / or FFA refining before undergoing a transesterification process to convert the refined raw material into crude biodiesel (150) and finally a biodiesel purification process (243) to produce high-quality purified biodiesel (160) that meets multiple commercial specifications. During this process, valuable chemicals contained in the unsaponifiable material are subjected to various processing conditions and are ultimately separated from the biodiesel residue (180) as co-products of the purified biodiesel (160). An illustrative method (100) is detailed with reference to FIG. 1 for processing the raw material (105) into glycerin (145) and biodiesel. 238882 1944035 of 44 purified (160) that meets the commercial specifications of the product and biodiesel residue (180). Raw feedstocks (105) arrive at the biodiesel production facility and are unloaded into the raw feedstock storage tank. Compatible feedstocks can be combined and stored in a shared tank before processing. The raw feedstock (105) first undergoes a feedstock pretreatment process (110) that relies on its FFA content and other properties to produce a pretreated feedstock (115). Alternatively, the feedstocks may arrive at the biodiesel production facility already refined elsewhere, in which case they can be unloaded directly into the refined feedstock storage tank. The pre-treated feedstock (115) can then undergo an FFA refining process (120) that removes FFAs (dotted line 2). Optionally, FFA refining (120) can yield a crude biodiesel stream (150) when FFA removal is followed by esterification of the fatty acid distillate. Alternatively, FFA refining (120) can yield a glyceride stream (125) when FFA removal is followed by glycerolysis of the fatty acid distillate. In one embodiment, as shown by dotted line 1, pre-treated raw material (115) with sufficiently low levels of FFA to be classified as refined raw material (i.e., the raw material was chemically refined to remove FFA in the pre-treatment of the raw material (110) or refined elsewhere) can bypass the FFA refining unit (120). The refined feedstock (125) is processed in a transesterification process (130) to yield crude biodiesel (150) and crude glycerin (135). The crude glycerin (135) can be refined in a glycerin refining unit (140), yielding glycerin (145) that can be recycled in the FFA refining process (120) for glycerolysis. The crude biodiesel (150) undergoes a final biodiesel refining process (155) to produce a market-acceptable purified biodiesel product (160) and biodiesel residue (180) enriched in unsaponifiable material. Wet alcohol from the biodiesel refining (155) and glycerin refining (140) is sent to an alcohol recovery unit (165) to separate the water (175) and recover dry alcohol (170). The modalities of 238882 1944035 of 44 The unit operations of FIG. 1 are described in more detail in FIG. 2. Figure 2 shows process modes similar to those shown in Figure 1, except that Figure 2 shows additional modes and process stages in greater detail. The raw material (105) is received in the storage tank at the biodiesel production facility. Compatible raw materials may be combined and stored in a shared tank before further processing. The raw materials (105) are pretreated and refined as determined by their FFA content and other raw material properties. The raw material (105) may undergo a pretreatment stage by chemical refining (201) (dotted line A), degumming (202) (dotted line B), or bleaching and polishing (206) (dotted line C), depending on its physical and chemical characteristics.In both of the above-described modes, the raw material exiting the chemical refining unit (201) or the degumming unit (202) was processed in a centrifugal separator (204). The centrifugal separator unit (204) removes the aqueous phase and any hydratable or polar compounds from the raw material formed in unit (201) or (202), as well as any solids. This aqueous phase may be referred to as neutralization sludge (205) in both modes. Once the raw material (105) has passed through the centrifugal separator (204), it may undergo one or more drying, bleaching, and polishing stages in the unit (206), including heat bleaching or clay bleaching stages to reduce color, solids, residual soaps, moisture, and other impurities in the partially refined raw material. In one embodiment, the raw material is bleached and dried in the same operation in the unit. In another embodiment, the raw material is dried by a vacuum dryer, evaporation chamber, or other such means to a desired water content, either before and / or after entering the bleaching unit. The desired water content depends on the type of filter material used in the bleaching unit and the impurities present in the raw material at that time. After the raw material has been dried and bleached, it enters a polishing filter where any remaining filterable impurities are removed, along with any fine particles from the filter material left over from the bleaching stage. For raw materials containing waxy compounds, the preceding stages may remove a small amount of wax if... 238882 1944035 of 44 operates at low temperatures (e.g., < 140 °F). However, since wax is somewhat soluble in oil even at relatively low temperatures, a considerable portion of the waxes is retained in the feedstock and transferred to the biodiesel. Furthermore, the viscosity of oils and fats increases dramatically with decreasing temperature, meaning that lower refining temperatures can dramatically reduce the potential output of any filtration process unit operating at a lower temperature. En este momento, al menos algo del material insaponificable en la materia prima en bruto (105) permanece en la materia prima tratada previamente (115). Depending on the effectiveness of the strategic pretreatment process of the initial raw material and the FFA content of the pretreated feedstock, the pretreated feedstock (115) may optionally undergo further processing. If the free fatty acids were removed in the chemical refining unit (201) and centrifuge (204) in the form of neutralization sludge (205), the pretreated feedstock (115) may proceed directly to the transesterification process as a refined feedstock (125), as shown by the dashed line 1.However, a significant amount of free fatty acids (>0.2% by weight, for example) is retained because the raw material (105) was pretreated with a degumming process (202) (dotted line B) and / or a bleaching and polishing stage (206) (dotted line C). The pretreated raw material (115) requires further processing in either the FFA separation unit (210) or the FFA conversion unit (250). The free fatty acids in the raw material (105) are generally undesirable in the transesterification process (130) because they form soaps in the oil when they react with the base catalyst used to drive the transesterification reaction. Therefore, they must be removed, converted, or both.There are two primary processing options for reducing FFA levels in the pretreated raw material (115): 1) separation (or deacidification) to physically remove FFA from the raw material (210), and 2) chemical conversion by either esterification or glycerolysis (250). Glycerolysis is a subcategory of esterification in which glycerol, an alcohol, is used to convert FFA into glycerides, which are fatty acid esters of glycerol. An advantage of the present invention 17 238882. 1944035 of 44 with respect to the previous technique is that a raw material with any FFA content (0 - 100% by weight) can be processed with the appropriate raw material pretreatment method (110). In an embodiment shown by dashed line 2, free fatty acids are removed from the pretreated feedstock (115) along with other low molecular weight components relative to triglycerides, including tocopherols and sterols, in a physical refining step of FFA with distillation (210). Although the FFA separation step can be carried out on feedstocks with any FFA level, a preferred FFA level is between approximately 0.5 wt% and approximately 30 wt%. The FFA separation step (210) can employ steam, hot oil, or another thermal fluid to heat the raw feedstock. Distillation can be carried out under vacuum to remove free fatty acids from the oil phase by evaporation in unit (210).The FFA separation step (210) may employ a distillation column, a stirred-film evaporator, and other such equipment and may optionally include steam injection into the distillation unit to facilitate the separation of the FFAs from the remaining feedstock. Two product streams can be produced from the FFA separation (210): a relatively pure fatty acid distillate (211) consisting of more than about 50 wt% FFAs as well as small amounts of tocopherols and sterols, and the separated feedstock (212) containing less than about 0.5 wt% FFAs and small amounts of steryl esters. The separated feedstock stream (212) is sufficiently purified during the FFA separation (210) to allow it to enter the transesterification process as a refined feedstock (125).The fatty acid distillate stream (211) can be sold as a final product or can be subjected to further processing to chemically convert the FFAs into unit (250) (dotted line 4). In another embodiment, the pre-treated raw material (115), which includes small amounts of unsaponifiable material, is processed directly in unit (250). Raw materials containing between 0.1 and 100% FFA by weight can be processed in the FFA conversion unit (250) to convert the FFA into esters by esterification or glycerides by glycerolysis (dashed line 3). The fatty acid distillate (211) from the FFA separation (210) can be processed in the FFA conversion unit (250) (dashed line 3). 238882 1944035 of 44 dotted 4). In one embodiment, the pre-treated feedstock (115) (following the dotted arrow 3) and / or the fatty acid distillate (211) (following the dotted arrow 4) is esterified to form alkyl esters in unit (213). In this embodiment, the free fatty acids can be esterified with a homogeneous catalyst and / or heterogeneous catalyst with an alcohol (e.g., dry alcohol from unit 170) to form fatty acid alkyl esters. When the pre-treated feedstock (115) or the fatty acid distillate (211) is processed by esterification in the FFA conversion unit (213), the unsaponifiables also react to some extent. For example, sterols can form steryl esters with the free fatty acids.Therefore, the product, whether refined raw material (125) in the case of esterification of the previously treated raw material (115) or crude biodiesel (150) in the case of esterification of fatty acid distillate (211), will likely contain a combination of tocopherols, sterols, terpenes, and steryl esters. In another embodiment, the pre-treated feedstock (115) (following the dotted arrow 3) and / or the fatty acid distillate (211) (following the dotted arrow 4) is subjected to glycerolysis to form glycerides in unit (213). In this embodiment, the free fatty acids from the pre-treated feedstock (115) or the fatty acid distillate (211) can be reacted with glycerin from unit (145) in the FFA conversion unit (250) to form monoglycerides, diglycerides, and triglycerides, which can then be transesterified to produce biodiesel. Various process equipment in the FFA conversion unit (250) can be used to reduce the FFA from the glycerolysis outlet stream to less than about 5 wt%, 4 wt%, 3 wt%, 2 wt%, 1 wt%, 0.5 wt%, 0.3 wt% or 0.1 wt% FFA before entering transesterification as refined feedstock (125). Similarly, unsaponifiable material in the raw or pretreated feedstock (115) or fatty acid distillate (211) can react under glycerolysis conditions. In particular, free sterols can form steryl esters with free fatty acids present in the raw or pretreated feedstock. Recently, steryl esters have received increasing attention as a valuable chemical of interest for 19 238882 1944035 of 44 nutraceutical industry. Therefore, the feedstock (105) containing any amount of FFA can be processed by at least one of the FFA pretreatment (110) and refining (120) methods described above, whereby the FFAs are removed in a chemical refining unit (201), a physical refining unit (210), and / or converted by esterification or glycerolysis in an FFA conversion unit (213). However, in each FFA pretreatment (110) and refining (120) approach, a small amount of free fatty acids typically remains and ends up in the finished biodiesel product, increasing the acid number of the biodiesel. Once the raw material has been pretreated (110) and refined (120), it enters the transesterification process (130) and then the biodiesel refining process (155). There are several processes that can be used to produce biodiesel from oils and fats, including basic catalytic transesterification, acid catalytic transesterification, and enzymatic transesterification. In one embodiment, biodiesel is produced from feedstock by basic catalyst transesterification in one, two, three, or more reactors. In another embodiment, the refined feedstock (125) undergoes a transesterification reaction process and is then refined to produce purified biodiesel (160) and glycerin (145). The transesterification reaction mixture exits the reactor (220) and enters a phase separation unit (222). In the phase separation unit (222), the reaction mixture is separated into two phases: an ester-rich phase (crude biodiesel) that is transferred to one or more additional reactors (223), and a glycerin-rich phase (crude glycerin) that is collected in unit (135). Crude glycerin (135) is denser than crude biodiesel (150) and the two phases can be separated by gravity separation in a settling tank or, if needed or desired, by centrifugal separation.The unsaponifiable material tends to remain in the crude biodiesel (150) during the separation process. Once the transesterification reaction is complete in the second reactor (223), the reaction mixture enters a second-stage separation unit (224). In one embodiment, the acid (225) is mixed with the reaction mixture leaving the reactor (223) to deactivate the transesterification catalyst before it enters the separation unit. 238882 1944035 of 44 phases (224). In other embodiments, the catalyst is deactivated after the phase separation unit. The acid may be diluted with water (175) before being introduced into the reaction mixture in an acid dilution vessel (226). In the phase separation unit (224), the reaction mixture is again separated into two phases: an ester-rich phase or crude biodiesel (150) and a glycerin-rich phase or crude glycerin (135), which is sent to unit (230). Each of these crude phases may include a significant amount of excess alcohol used in the reaction. In addition, the crude reaction products may include other impurities such as catalyst, soaps, salts, water, and excess high-boiling impurities. In one embodiment, some or all of these impurities can be treated or removed from the crude reaction products before the biodiesel and glycerin phases are separated in the unit (224).However, unsaponifiable material tends to remain with crude biodiesel (150), even after other impurities have been treated or removed with crude glycerin (135). The crude biodiesel (150) exiting the phase separation unit (224) will still contain impurities and unsaponifiable material and must therefore be purified in one or more operations. The order and number of these operations can vary depending on the properties of the raw feedstock, the pretreatment process, the transesterification process, and economic feasibility. After the crude biodiesel (150) is separated from the crude glycerin (135) in unit (224), it is typically subjected to further biodiesel refining (155). For example, after separation, the crude biodiesel may contain residual alcohol, glycerin, small amounts of catalyst, salts, and soaps. This can be the case even if the crude reaction products are refined to remove or neutralize impurities before separation. Depending on the raw material, its impurities, and the unsaponifiable material, the biodiesel purification unit (243) may differ. In one embodiment, the crude biodiesel (150) undergoes a cold filtration process in unit (243) so that high-melting-point components, such as proteins, waxes, and certain unsaponifiable material, are cooled below their solubility point and removed by filtration. Cold filtration techniques may utilize diatomaceous earth (DE) or other filter media to increase filtration efficiency. In this way, biodiesel can be produced in 238882 1944035 of 44 gross (150) that meets market cold immersion filtration tests. In a cold filtration process, the unsaponifiable material captured in the filter cake can be recovered using a variety of separation and extraction processes to produce valuable chemicals. In general, combining the cold filtration option with feed pretreatment (110) and FFA refining (120) has many advantages. However, certain feeds can cause filters to clog more quickly and require more frequent downtime for filter changes, resulting in higher operating costs. Furthermore, filtration may not be able to remove sufficient quantities of these components under reasonable operating conditions at desired production rates.Such raw materials include those containing unsaponifiable material, such as corn oil, sunflower oil, olive oil, carrageenan oil, some poultry fats, and some microbial or algal oils. Due to their solubility in FAAE over a wide temperature range, waxes and certain other unsaponifiable materials cannot always be completely and economically removed from the finished biodiesel using a combination of a pretreatment process (110), an FFA refining process (120), and a cold filtration process or similar winterizing technique. In another embodiment, crude biodiesel (150) undergoes membrane filtration in unit (243) so that high-melting-point components, such as proteins, waxes, and certain unsaponifiable material, condense and are removed below their melting point. Membrane filtration can be performed at low temperatures so that the condensed materials are more easily filtered out, or at higher temperatures using membranes with very small pores that can separate larger or more polar molecules from a solution (e.g., nanofiltration). In this way, it is possible to make crude biodiesel (150) meet certain commercial specifications. Membrane filtration techniques can include ceramic membranes, polymer membranes, molecular sieves, and carbon fibers or nanotubes.In one embodiment, the product exiting the phase separation unit (241) can enter directly into a membrane filtration unit that removes both methanol and water instead of passing through a biodiesel alcohol separator (242). With this approach, the unsaponifiable material... 238882 1944035 of 44 can be recovered from membranes using various solvent extraction techniques to provide valuable chemicals. In another embodiment, the crude biodiesel (150) undergoes a resin filtration process in unit (243) to remove impurities, including wastewater. This allows the crude biodiesel (150) to meet specific commercial specifications. Resin filtration techniques may include dry-scrubbing resins, ion-exchange resins, and other absorbent or adsorbent resins. In one embodiment, the product exiting the phase separation unit (224) or (241) can be fed directly into a resin filtration unit, which can remove methanol, glycerin, water, and other impurities instead of passing through additional purification units. Again, some of the unsaponifiable material from the resin filters can be recovered with various solvents to produce valuable chemicals. These same solvents can be used to regenerate or reactivate the resins. In another embodiment, crude biodiesel (150) can be purified by distillation in unit (243) to remove or reduce the levels of unsaponifiable material, soaps, phospholipids, proteins, color compounds, sulfur compounds, high-boiling compounds with acidic or basic functional groups, and monoglycerides, diglycerides, and triglycerides in the form of distillation bottoms (180). The resulting distilled biodiesel (160) is purified and should be commercially acceptable despite the problematic components present in the initial raw material. Such a distillation process can be carried out using various process equipment, including evaporation vessels, distillation vessels, distillation columns, short-path distillation, stirred-film evaporators, thin-film evaporators, falling-film evaporators, and other thermal separation strategies. The unsaponifiable material recovered from the biodiesel residue (180) is generally less than approximately 10%, 8%, 6%, 4%, 2%, and 1% by weight of the crude biodiesel (150) entering the biodiesel purification unit (243). However, due to the large capacities of a biodiesel plant, this can amount to significant quantities. As such, the unsaponifiable material in the 23 238882 1944035 of 44 biodiesel residue (180) can be a source of components such as sterols, steryl esters, steryl glycosides, terpenes, tocopherols, vitamins, sulfolipids, proteins, hydroxycinnamic acids, myricyl esters of fatty acids, waxes, flavonoids, carotenoids and other valuable chemicals. In one embodiment, purification in the biodiesel purification unit (243) will produce a biodiesel residue product (180) which, with further purification (260), is a concentrated and economical source of valuable chemicals (261). Various methods for purifying and obtaining valuable chemicals (261) from the biodiesel residue (180) in the unit (260) include: saponification, transesterification, esterification, hydrolysis, precipitation, sedimentation, crystallization, distillation, and solvent separation techniques. In one embodiment, biodiesel purification in unit (243) is by distillation to purify crude biodiesel by reducing the protein and unsaponifiable material content, so that the purified biodiesel product passes cold immersion filtration tests. In another embodiment, biodiesel distillation in unit (243) purifies crude biodiesel to remove unsaponifiable material and other compounds, resulting in a second inflection point and a high acid number when titrated according to ASTM D664-17, Method B, such as hydroxycinnamic acids. In yet another embodiment, biodiesel distillation in unit (243) purifies crude biodiesel to remove unsaponifiable material, so that the purified biodiesel product has increased FAAE content and / or improved filtration capacity.In one embodiment, biodiesel distillation in unit (243) purifies crude biodiesel to reduce color compounds, so that the purified biodiesel product is lighter in color than the original feedstock. In another embodiment, biodiesel distillation in unit (243) purifies crude biodiesel to reduce color compounds, so that the purified biodiesel product meets color requirements for customer acceptance and / or is not similar to dyed off-highway diesel. In yet another embodiment, biodiesel distillation in unit (243) purifies crude biodiesel to remove glycerides, so that the purified biodiesel product meets commercial monoglyceride specifications, such as the new monoglyceride specification in ASTM D6751-18, and future specifications in 24 238882. 1944035 of 44 glycerides, if introduced. In one embodiment, the distillation of biodiesel in unit (243) purifies the crude biodiesel to remove a portion of the sulfur-containing species, so that the purified biodiesel product meets the commercial sulfur limits in ASTM D6751-18 and future sulfur specifications, if the current limits are adjusted. In one method, biodiesel distillation occurs between 170–300 °C and 800–0 Torr. In another method, biodiesel distillation occurs between 200–300 °C and 800–0 Torr. In yet another method, biodiesel distillation occurs between 230–290 °C and 40–0 Torr. In still another method, biodiesel distillation occurs between 240–280 °C and 5–0.01 Torr. In one embodiment, the biodiesel product (160) produced from a biodiesel purification process (243) shall have a wax content of less than about 0.1% by weight, an unsaponifiable material content of about 2% by weight or less, a soap content of about 50 ppm or less, a sulfur content of about 500 ppm or less, a monoglyceride content of less than about 0.6% by weight, a cold immersion filtration result of about 360 seconds or less, and a lighter color than the original feedstock. In another embodiment, the biodiesel product (160) produced from a biodiesel purification process (243) shall have a wax content of less than about 0.05% by weight, an unsaponifiable material content of about 1% by weight or less, a soap content of about 20 ppm or less, a sulfur content of about 15 ppm or less, a monoglyceride content of less than about 0.5% by weight, a cold immersion filtration result of 240 seconds or less, and a lighter color than the original raw material. In one embodiment, the biodiesel product (160) produced from a biodiesel purification process (243) shall have a wax content of less than about 0.01% by weight, an unsaponifiable material content of about 0.5% by weight or less, a soap content of about 10 ppm or less, a sulfur content of about 10 ppm or less, a monoglyceride content of less than about 0.4% by weight, a cold immersion filtration result of about 200 seconds or less, and a lighter color than the original raw material. Traditional raw material pretreatment techniques remove very little 238882 1944035 of 44 unsaponifiable material. In one embodiment, a portion of the unsaponifiable material is removed in the FFA separator in a product called fatty acid distillate. The fatty acid distillate contains mainly FFAs but also tocopherols, sterols, mono- and diglycerides, and other unsaponifiable material. Some compounds, such as steryl esters, for example, have a sufficiently high boiling point to remain predominantly in the glycerides and continue with the separated feedstock, ultimately ending up in the crude biodiesel. There are several options for processing fatty acid distillate. In one method, glycerin is added to the fatty acid distillate in a glycerolysis reaction. During the reaction, the fatty acid distillate (FAD) is broken down into monoglycerides, diglycerides, and triglycerides, while some of the sterols react with the FAD to form steryl esters. Once sufficient FAD is consumed in the glycerolysis reaction and the water is removed, the product emerges as a raw material containing glycerides, tocopherols, steryl esters, and residual water. In one embodiment, crude biodiesel is dried in an alcohol separator (242) to remove water and alcohol as wet alcohol. The dried biodiesel can be purified in unit (243) using a number of techniques where unsaponifiables can be recovered. In one embodiment, the dried biodiesel is purified in unit (243) by distillation to separate the unsaponifiable material and impurities by concentrating them in the distillation bottoms (180). The distillation bottoms (180) then contain a significant amount of unsaponifiable material from which valuable chemicals such as tocopherols, sterols, steryl esters, terpenes, sulfolipids, proteins, hydroxycinnamic acids, myricyl esters of fatty acids, waxes, flavonoids, carotenoids, and other valuable chemicals can be recovered. Valuable chemicals of interest can be recovered from biodiesel residue (180) by exploiting differences in solubility in various solvents. In one embodiment, the biodiesel residue (180) can first be treated with a low molecular weight, very nonpolar solvent, such as hexane or heptane, to remove waxes, terpenes, and other components of interest by sedimentation. The recovered liquid phase can then be treated with a more polar and denser solvent, such as an alcohol, to recover a 238882 1944035 of 44 biodiesel blend component in the heavy phase (alcohol). The sterols and steryl esters from the biodiesel residue (180) are now enriched in the original solvent and can be recovered by solvent evaporation to leave a solid or gel sediment. In another embodiment, the biodiesel residue (180) can be first treated with a moderately polar solvent, such as acetone or ethyl acetate, to produce a sediment enriched in waxes, terpenes, and other components, and a supernatant liquid. The sediment can be treated at least a second time with a slightly polar solvent to recover additional components of interest in a supernatant liquid phase. All these liquid phases are then combined to provide a solvent stream enriched in biodiesel, glycerides, sterols, and steryl esters. The solvent stream can then be treated with water to produce a water layer and a sediment enriched in sterols and steryl esters. Above this water layer is an organic phase enriched in biodiesel and glycerides, which can be recycled, after removal of the residual solvent, as a biodiesel blending component or as a biofuel feedstock, depending on its composition. With at least some of the unsaponifiable material removed from the biodiesel residue (180), the remaining biodiesel residue (180) can also have an increased value, either as a biodiesel blending component or as a biofuel feedstock. In some embodiments, the remaining biodiesel residue (180) can be recycled as a feedstock for a biofuel production process. In another embodiment, at least some of the remaining biodiesel residue (180) can be blended with the finished biodiesel, as the removal of the unsaponifiable material improves its quality as a biodiesel blending component. Another aspect of the invention relates to the conversion of biodiesel residue (180) (or other biological feedstock (301) with a high unsaponifiable material content) into diesel-range hydrocarbons by hydrodeoxygenation. Surprisingly, it was observed that biodiesel residue (180), such as distillation bottoms and other biological feedstocks containing relatively high concentrations of unsaponifiable materials, at least 2%, and preferably at least 4%, and comprising at least 20% heavy hydrocarbon products (which 238882 1944035 of 44 are defined herein as the mass fraction with a boiling point greater than about 400 °C according to a test method such as ASTM D2887-18 or ASTM D7169-11) that can be converted into hydrocarbons of the diesel range. In some embodiments, the high unsaponifiable biological matter comprises crude Tall Oil. For the description of the invention, a preferred embodiment is presented in FIG. 3. With reference to FIG. 3, a biological feedstock (301) comprising free fatty acids, fatty acid esters (including monoglycerides, diglycerides, and triglycerides), and unsaponifiable materials at concentrations greater than or equal to 2%, preferably greater than 4%, is combined with a hydrocarbon oil diluent (311) to provide a diluted biological feedstock (301A). In some embodiments, the biological feedstock (301) comprises biodiesel residue (180) such as distillation bottoms. The diluent-to-feedstock ratio (i.e., the volumetric ratio of the flow of 311 to the flow of 301) is between 1:1 and 20:1, preferably between 2:1 and 4:1.In some embodiments, the biological raw material (301) comprises unsaponifiable materials such as sterols and steryl esters (reaction products of sterols and carboxylic acids). To quantify the percentage of unsaponifiables in the steryl esters, it is assumed that 60% of the mass of the steryl ester is an unsaponifiable sterol. (This is based on the sterol being campesterol, C28, and the carboxylic acid being oleic acid, C18.) The biological raw material may additionally contain 0 to 1% free glycerin. The saponifiable components comprise free fatty acids and fatty acid esters, including fatty acid methyl / ethyl esters and glycerides (i.e., monoglycerides, diglycerides, and triglycerides). With regard to total oxygen heteroatoms, the biological raw material (301) preferably contains between 8 and 14% by weight of elemental oxygen. Hydrocarbon oil thinner (311) is primarily hydrocarbons. In some embodiments, hydrocarbon oil thinner (311) is more than 99% hydrocarbons. These comprise hydrocarbons from petroleum, coal, natural gas, bitumen (oil sands), or biological sources. Hydrocarbon oil may include up to 0.1% by weight of oxygen, nitrogen, and sulfur each, including from additives (e.g., corrosion inhibitors, antioxidants, etc.). In some embodiments, hydrocarbon oil has 28 238882 1944035 of 44 less than 90% saturates. In some embodiments, the hydrocarbon oil has no more than 5% aromatic hydrocarbons, preferably no more than 1%. In some embodiments, the hydrocarbon diluent has no more than 10% olefins, preferably no more than 2%. The hydrocarbon oil is preferably in the middle distillate range with an initial boiling point greater than 177 °C and 90% of the distillation temperature less than 330 °C, comprising C15-C18 paraffins. Referring again to FIG. 3, the vapors from 301 and 311 are transferred to a hydrodeoxygenation (HDO) reactor system (300). The diluted biological feedstock (301A) and a hydrogen-rich gas (H2) feedstock (302), also at or above the reactor system pressure, are introduced into the HDO reactor system (300). In some embodiments, the H2-rich gas (302) has a hydrogen concentration of between 70 and 100 mol%. There, the feedstocks are combined and heated to a reactor inlet temperature. In some embodiments, the HDO reactor system includes provisions for heating feedstocks (302) and (301A) together or separately. In some embodiments, the biological feedstock (301) is not heated directly, but instead is heated by contact with the preheated feedstocks (311) and / or (302).In some embodiments, dilute biomaterial (301A) and H2-rich gas (302) are contacted with a hydrodeoxygenation catalyst at a temperature between 500 °F (260 °C) and 700 °F (371 °C) at a reactor pressure of 500–2500 psig. The HDO reactor is a fixed-bed reactor equipped with hydrotreating catalysts. The hydrotreating catalysts are generally extruded alumina products impregnated with Ni (1–20%), Mo (2–40%), Co (1–20%), or W (2–40%). These catalysts have the desired HDO activity / selectivity in sulfide form (i.e., as Ni3S2, MoS2, WS2, Co9S8). To ensure that the catalyst is kept in the desired sulfide state, a sulfur compound such as dimethyl disulfide is added to the material, typically in the range of 100-1000 wppm (sulfur in biological matter).Fixed-bed HDO reactors typically operate adiabatically, meaning the heat of reaction is not directly removed from the reactor. In such operating modes, the temperature rise in the reactor due to the heat of reaction is controlled by introducing unheated H2-rich gas (flow 302) or unheated liquid (flow 301, 311, or 301A) into the reactor for inactivation. 238882 1944035 of 44 In some configurations, the HDO reactor is a slurry reactor (e.g., a slurry bubble column reactor). Slurry reactors typically use powdered catalysts in the 40–100 micron range instead of extruded products; however, the catalytic composition is similar to that of extruded products in terms of base metal content. Again, with reference to FIG. 3, a reactor effluent (304) comprising the reaction products and byproducts is cooled in a cooling system (303). The reaction products comprise a lower-oxygen biological product and reaction byproducts comprising a vapor phase, water, and carbon oxides (CO / CO2). In some embodiments, the reaction effluent (304) has a temperature in the range of 550 °F (288 °C) to 800 °F (427 °C). The cooling system (303) cools the reactor effluent (304) to a temperature between 200 °F (93 °C) and 350 °F (177 °C) so that the lower-oxygen product is cooled and the condensable vapor-phase byproducts are condensed. A cold reactor effluent (304A), comprising a liquid phase and a gaseous phase, is transferred to a three-phase separator 305, where it is separated into a gaseous phase (306), a hydrocarbon phase (307), and an aqueous phase (306A).The three-phase separator (305) operates at the HDO reactor system pressure, less the in-line flow pressure drop. In some embodiments, cooling / condensation and separation are achieved in multiple stages, comprising a "hot separator" and a "cold separator." The gas phase (306) comprises unreacted H2, along with the reaction co-products / by-products: propane, CO, CO2, and H2S. Since most of the biological feedstock contains nitrogen compounds, the gas phase (306) also typically includes NH3. In some embodiments, the gas phase (306) is combined with H2-rich gas (302) and recycled in an HDO reactor system (241). In some embodiments, the gas phase (306) is purified, for example, by scrubbing (i.e., gas absorption) using caustic or amine solutions, to remove at least some of the CO2, H2S, and NH3. The aqueous phase (306A) comprises water produced during the hydrodeoxygenation of oxygen heteroatoms in biological matter. Despite containing dissolved species 30 238882 1944035 of 44 sulfide, carbonate and ammonium, the pH of the aqueous phase (306A) is generally close to neutral (6.5-7.5) The hydrocarbon phase (307) is the lowest oxygen product of the hydrodeoxygenation of biological material (301), comprising less than 0.1 wt% oxygen. Additionally, the lowest oxygen product comprises at least 90% saturated hydrocarbons (paraffins, isoparaffins, and cycloparaffins combined), less than 5% olefinic hydrocarbons, less than 1% aromatic hydrocarbons, and includes C15-C18 paraffins. The hydrocarbon phase (307) can be separated from dissolved H2S, H2O, and NH3 in a separator (308). The separator (308) operates at a lower pressure than the three-phase separator (305), typically in the range of 0 to 150 psig. In some embodiments, a separating gas such as steam or nitrogen is used to achieve better removal of dissolved acid gases and water. Therefore, a main separator vapor stream (310) comprising H2S, H2O, NH3 is removed from the separated hydrocarbon product (309). In some embodiments, the separated hydrocarbon product (309) is a hydrocarbon comprising less than 0.1 wt% oxygen, less than 10 ppm sulfur, less than 10 ppm nitrogen, and less than 200 ppm water; preferably less than 100 ppm. The hydrocarbon has an initial boiling point greater than 177 °C and a 90% distillation temperature less than 338 °C (as measured by ASTM D86 standard test method or equivalent) and comprises C15-C18 paraffins. In some embodiments, the hydrocarbon diluent (311) comprises the hydrocarbon phase (307). In some embodiments, the hydrocarbon diluent (311) comprises the separated hydrocarbon product (309). In some embodiments, the separated hydrocarbon product (309) is used as a diesel fuel additive. In some embodiments, the separated hydrocarbon product (309) is subjected to hydrocracking and / or hydroisomerization (312), according to prior art methods, to improve the low-temperature properties (e.g., cloud point) of the hydrocarbon product (309) for use as a diesel fuel. In some embodiments, the hydrocracked and / or hydroisomerized hydrocarbon (313) is fractionated into renewable diesel / jet fuel and naphtha fractions. 238882 1944035 of 44 In a related aspect, biodiesel residue (180) can be recovered, such as the distillation bottoms from at least one transesterification or esterification of unconventional lipids. In one embodiment, biodiesel residue (180) can be recovered using the processes described above. Unconventional lipids are defined herein as those characterized by a fatty acid profile that includes at least 20% by weight of fatty acids with a chain length of 20 carbons or more (i.e., 20% C20+ fatty acid content). Examples of such lipids include carinata oil with 55–57% C20+ fatty acids, high erucic rapeseed oil with 52–60% C20+ fatty acids, and Lesquerella fendleri (a flowering plant in the mustard family) with 65–68% C20+ fatty acids.These unconventional lipids are generally unsuitable for human consumption, grow in soil that is generally unsuitable for agriculture, and have a higher energy content (heat of combustion) than conventional vegetable oils and animal fats. As such, the plants that produce these oilseeds are frequently called "energy crops." In principle, such unconventional lipids should be attractive for their biofuel production. However, biodiesel produced from such lipids typically has 90% of the distillation recovery temperature (i.e., T90 per ASTM D1160-15) greater than 360 °C and therefore does not conform to the ASTM D6751-18 biodiesel specification, which limits T90 to a maximum of 360 °C. In some embodiments, a feedstock comprising non-conventional lipids is subjected to transesterification with methanol to yield fatty acid methyl esters (FAMEs) with a range of fatty acid chain lengths. Even when mixed with conventional C16 / C18 fatty acid lipids, the C20+ fatty acids in the transesterified lipid mixture constitute at least 10% by weight. Transesterification methods and systems are described in the prior art and earlier in this specification. Those skilled in the art recognize that while methanol is described as the light alcohol for transesterification with the non-conventional lipid, other light alcohols such as ethanol and C3 / C4 alcohols (e.g., isobutanol) can be used to produce fatty acid alkyl esters. The transesterification reactor effluent comprises light esters (e.g., FAAEs with fatty acid chains). 238882 1944035 of 44 fatty acids shorter than or equal to C16), alkyl esters of C18 fatty acids (e.g., methyl oleate and methyl linoleate), heavy esters (e.g., FAAE with C20+ fatty acids), glycerin and unconverted glycerides, and unsaponifiable materials. This stream is subjected to glycerin separation and biodiesel distillation, as described above. In the present embodiment, the distillation is carried out so that a biodiesel distillate comprising mainly C18 fatty acid esters is recovered for use in compression-ignition engines, as a heating fuel, or as a fuel for electric generators. Although the biodiesel product comprises C18 fatty acids from non-conventional lipids, it fully conforms to the ASTM D6751-18 biodiesel specification, including the maximum T90 value of 360°C as measured by the standard test method (ASTM D1160-15). The distillation bottoms fraction in this embodiment comprises C20+ fatty acids, unconverted glycerides (monoglycerides, diglycerides, and triglycerides), and unsaponifiables as described above. In some embodiments, the distillation bottoms comprise at least 15% by weight of C20+ fatty acids. In some embodiments, the C20+ fatty acid content of the distillation bottoms ranges from 15% to 90% by weight. The distillation bottoms are subsequently subjected to hydrodeoxygenation as described above when referring to Fig. 3 in general and to the HDO reactor system therein (reference element 300) in particular. The HDO product in this embodiment comprises n-paraffins from the hydrodeoxygenation of the fatty acid from an unconventional lipid (using the C20+ fatty acid FAME intermediate). The hydrodeoxygenation of the distillation bottoms thus produces a lower-oxygen product comprising less than 0.1 wt% oxygen, at least 90% saturated hydrocarbons (paraffins, isoparaffins, and cycloparaffins combined), less than 5% olefinic hydrocarbons, and less than 1% aromatic hydrocarbons. The saturated hydrocarbons comprise C15-C18 n-paraffins and C20+ n-paraffins. In some forms, saturated hydrocarbons comprise C15-C24 n-paraffins.In some forms, the lower oxygen product comprises at least 5% by weight of C20+ n-paraffins. In some forms, the lower oxygen product comprises at least 10% by weight of n33 238882. 1944035 of 44 C20+ paraffins. In some forms, the product with the lowest oxygen comprises at least 20% by weight of C20+ n-paraffins. The lower-oxygenated product from the hydrodeoxygenation of the distillation bottoms is subsequently separated in unit (308) to remove any gas-phase byproducts (310), including C1-C3 hydrocarbons, H2S, NH3, water, CO, and CO2. In some embodiments, the separated hydrocarbon product (309) is subjected to hydrocracking and / or hydroisomerization (312), according to prior art methods, to improve the low-temperature properties (e.g., cloud point) of the lower-oxygenated product for use as diesel fuel. In some embodiments, the hydrocracked and / or hydroisomerized hydrocarbon (313) is fractionated into renewable diesel / jet fuel and naphtha fractions. Despite the high concentration of C20+ n-paraffins, 90% of the recovery temperature (according to method D8616a) of the diesel product is 338 °C or less. In other embodiments of the present invention, light esters (FAAE with C16 or shorter fatty acid chains as determined by AOCS EC 1-62) are separated as a light distillation cut, with biodiesel (FAAE with predominantly C18 fatty acids) as the heart cut. C16 and shorter fatty acids (i.e., light esters) contain a higher proportion of saturated fatty acids than C18 and longer fatty acids and therefore have a detrimental impact on the cold flow properties of biodiesel. Thus, the removal of light esters improves the biodiesel product. In one embodiment, the light esters and distillation bottoms can be combined to provide the feedstock for hydrodeoxygenation. In another embodiment, the light esters can be used as biofeedstock for the hydrodeoxygenation reactor system for the production of C16 or shorter hydrocarbons. In other arrangements, a portion or residue of the distillation bottoms can be used as raw material for further biological, chemical, or thermal processing, such as microbial digestion, hydroprocessing, pyrolysis, or other processes, for fuels or other valuable compounds. The invention is illustrated in detail below with reference to the examples, 238882 1944035 of 44 although it is not restricted to them. EXAMPLES Example 1: Recovery of unsaponifiable material from a biodiesel production and purification process Corn oil from a dry-milling ethanol plant was processed into a biodiesel processing facility. The crude corn oil feedstock was bleached and polished to remove minor contaminants, becoming a pre-treated feedstock. Fatty acids (FAs) were then removed from the pre-treated feedstock via FFA separation, yielding a fatty acid distillate and a separate feedstock. The separate feedstock was converted into crude biodiesel via transesterification, while the fatty acid distillate was esterified at a separate location, also providing crude biodiesel. The crude biodiesel was then dried to remove alcohol and water and subsequently distilled, yielding purified biodiesel and distillation bottoms. Example 2: Characterization of biodiesel distillation bottoms The bottoms fraction (residue) from the biodiesel distillation was analytically characterized using gas chromatography. The results are reported in Table 1. Table 1. Composition of the biodiesel distillation bottoms from Example 2 Component Composition (% by weight) Steryl esters 53.0% Methyl esters 15.7% Ethyl esters 0.5% Free sterols 4.1% Triglycerides 6.4% Diglycerides 1.9% Monoglycerides 1.1% Total glycerin 1.4% A final analysis carried out on the biodiesel distillation bottoms revealed the elemental composition shown in Table 2. 238882 1944035 of 44 Table 2. CHNSO analytical results for the biodiesel distillation bottoms from Example 2 Element Composition (% by weight) Carbon (C) 76.7% Hydrogen (H) 10.9% Nitrogen (N) 0.1% Sulfur (S) 0.0% Oxygen (O) 12.3% Example 3: Purification of the free sterol / steryl ester mixture from biodiesel distillation bottoms using acetone Four milliliters (4 g) of biodiesel distillation bottoms and 10 milliliters (7.3 g) of acetone were added to a 14-milliliter centrifuge tube. The mixture was then mixed and centrifuged. After centrifugation, the acetone liquids (9 g) were decanted into a separate 14-milliliter centrifuge tube. The remaining residue layer (2.3 g) was then recycled and extracted again with acetone. 0.5 mL of deionized water was added to the acetone liquids in the 14-milliliter centrifuge tube, mixed, and centrifuged. The upper-phase liquids were then decanted, yielding a remaining residue layer (2.7 g) enriched in sterol / sterol ester components, as determined by FTIR. Indication was provided that the sterol / sterol ester components enriched from the dry solids by the retention of sterol absorbance at 800 cm1 and the decrease in absorbances to 1742 cm1 and in the region of 1250 to 1000 cm1.The solids in the decanted acetone / water phase showed a decrease in absorbance at 800 cm1 and increases in absorbance at 1742 cm1 and in the region of 1250 to 1000 cm1. Example 4: Removal of esters and aromatic components from the sterol / steryl ester mixture recovered from the distillation bottoms of biodiesel with heptane and methanol. Four milliliters of biodiesel distillation bottoms and 10 milliliters of heptane were added to a 14-milliliter centrifuge tube. The contents were then mixed and centrifuged. The heptane-soluble liquids were decanted into a separate 14-milliliter centrifuge tube. The 36 238882 1944035 of the 44 remaining residue layer, now enriched in waxes and aromatic components. An aliquot of methanol was then added to the heptane-soluble liquids, mixed, and centrifuged. The resulting layers were then separated. Each layer was then dried and analyzed by FTIR. The solids in the heptane layer retained sterol absorbances but showed decreases in ester absorbances. The solids in the methanol layer decreased in sterol absorbances and retained ester absorbances compared to the distillation bottoms of the starter biodiesel. Example 5: Pretreatment of biodiesel distillation bottoms Biodiesel distillation bottoms were obtained from a biodiesel production facility operating with a feedstock composition comprising used cooking oil, non-edible corn oil, and brown grease. Crude methyl esters were produced from the lipid feedstock by transesterification in the presence of methanol and a potassium methoxide catalyst. The potassium methoxide catalyst was neutralized with glacial acetic acid to produce potassium acetate salts. The crude methyl esters were distilled in a stirred-film evaporator operating at approximately 240 °C and 5.5 Torr under vacuum. The yield of biodiesel distillation bottoms was approximately 9% by weight based on the distillate. The biodiesel distillation bottoms were subjected to a pretreatment process to reduce the concentration of inorganic impurities (e.g., primary potassium acetate). The first stage of the pretreatment process consisted of heating the distillation bottoms to approximately 80–85 °C, dosing 5 wt% of a 50 wt% aqueous citric acid solution and approximately 5 wt% water, and mixing for approximately 30 minutes in a stirring tank. The mixture was then centrifuged in a horizontal, three-phase centrifuge at approximately 6,000 g-force. Five gallons of the light phase from the centrifuge, comprising the washed distillation bottoms, were recovered and analyzed for alkalinity and metal composition. A summary of the metal reduction from the first stage is shown in Table 3. Table 3. Initial (i.e., crude) and final (i.e., refined) composition of the distillation bottoms of refined biodiesel from Example 5. Impurity Crude Refined % Reduction 238882 1944035 of 44 Alkalinity 60360.33 2152.27 96% Ca 145.412 2.14 99% Fe 44.812 4.77 89% K 2398.74 124.23 95% Mg 20.508 0.78 96% Mn 1.154 0.05 96% Na 34.514 2.47 93% P 6.13 4.48 27% Si 4.068 4.06 0% Total Metals 2655.34 142.98 95% The second stage of the pretreatment process consisted of three additional water washes. Each wash included the addition of 5 wt% water, cutting for 30 seconds at 80 °C, and batch centrifugation in a benchtop bucket centrifuge. The oil phase was recovered after centrifugation by pipetting. The impurity loading of the fully refined and washed distillate bottoms is shown in Table 4. Table 4. Impurity load of the fully refined and washed distillation bottoms from Example 5. Refined Impurity Washed 3x % Reduction Ca 2.1 0.7 67% Fe 4.8 0.6 87% K 124.2 10.4 92% Mg 0.8 0.1 83% Mn 0.1 0.0 100% Na 2.5 0.3 90% P 4.5 2.5 44% Total Metals 143.0 17.7 88% Example 6: Hydrodeoxygenation of biodiesel distillation bottoms A biological material was prepared by mixing one part by weight of biodiesel residue (treated according to Example 5) with four parts by weight of canola oil for hydrodeoxygenation (HDO) according to the present invention. A reactor was charged 238882 1944035 of 44 of 400 with two catalyst beds of equal volume: the upper bed contained a low-activity catalyst (3% base metal in alumina) and the lower bed contained a high-activity NiMo catalyst (18.5% total base metals in alumina). Both catalysts were commercially available petroleum refining catalysts, used for hydrodemetallization and hydrodesulfurization, respectively. The HDO reactor was configured for liquid material and hydrogen entering from the top and exiting through the bottom. The catalyst, supplied as a base metal oxide, was sulfided during reactor startup. The unsaponifiable-rich biological material was combined with a 10% hydrocarbon diluent. The hydrocarbon diluent was analyzed by GC and found to contain 1.18% n-tetadecane, 1.99% n-pentadecane, 15.46% n-hexadecane, 8.11% n-heptadecane, and 65.61% n-octadecane; the equilibrium concentrations were lower than those of linear C14-C18 olefins / isoparaffins, C19+ paraffins / olefins, and C13- paraffins / olefins. The sulfur and nitrogen content were 1.15 ppm and 0.61 ppm, respectively. The boiling point distribution data of the diluent and diluted biological matter (measured according to the simulated distillation method of ASTM D2887-18) are listed in Table 5. Table 5. Properties of the matter and the product of the HDO reactor of Example 6. Test Unit Diluent Diluted Biological Matter Sample Day 1 Sample Day 2 Sample Day 3 Density at 15.5 °C g / mL 0.8263 0.7889 0.7896 0.7899 Nitrogen (ppm) ppm 0.6 60.0 4.9 <1.0 <1.0 Sulfur (ppm) ppm 1.2 Observation 1 3.1 2.4 1.8 Acid Number mg KOH / g - - <0.05 <0.05 <0.05 SimDist IBP °C 215.9 39.3 204.4 216.5 217.4 5 % °C 285.9 259.2 279.4 286.6 286.7 10 % °C 287.2 282.6 287.2 287.4 287.4 238882 1944035 of 44 20% °C 292.9 283.7 301.6 302.1 302.1 30 % °C 309.6 305.4 311.2 314.3 314.8 40 % °C 316.4 312.0 315.9 316.2 316.2 50 % °C 317.1 312.3 316.2 316.4 316.4 60 % °C 317.6 312.6 316.5 316.7 316.6 70 % °C 318.0 313.4 316.7 316.9 316.8 80 % °C 318.3 479.6 316.9 317.1 317.1 90 % °C 318.7 560.1 317.3 317.4 317.5 90 % °C 318.9 594.0 343.3 347.0 368.1 FBP °C 452.3 626.9 470.3 475.7 478.4 Observation 1: Biodiesel distillation bottoms had 130 ppm sulfur before dilution; the diluted material was mixed with 350 ppm sulfur (as dimethyl disulfide). The HDO reaction conditions for continuous three-day running are listed in Table 6. Table 6. HDO operating conditions of Example 6 Parameter Operating Condition Temperature 600 °F (316 °C) Pressure 1800 psig Hourly Space Velocity of Liquid 1.0 h-1 Hydrogen to Liquid Matter Ratio 5000 SCF / bbl The reactor effluent was cooled and transferred to a high-pressure separator, where hydrogen-rich blowdown gas was separated from the effluent before the liquid was processed in an atmospheric-pressure separator column. The flow rate and composition of the gas / vapor streams from both the high-pressure separator and the separator column were measured using 10 wet gas flow meters and online GC analyzers. The gas stream composition showed the presence of 1–2 mol% CO2 along with 5–10 mol% C1C6+ hydrocarbons. The liquid from the separator column was collected in an accumulator and drained every 8 hours. These 8-hour composite samples were analyzed at least once daily for boiling point distribution (ASTM D2887-18), density, sulfur, nitrogen, and acid number. The results are presented in Table 5. 238882 1944035 of 44 The boiling point distribution results from Table 5 for the reactor material and its products are also presented graphically in FIG. 4. The reduction in density from 0.8263 to 0.7889–0.7899 indicates a considerable removal of oxygen. This is supported by the acid detection number below for all product samples. A reduction in high molecular weight species was also observed from the boiling point distribution data (ASTM D2887-18 analysis). Figure 4 shows a reduction in the 400 °C+ fraction from 25% to less than 5%. Since biodiesel distillation bottoms comprise mostly high molecular weight / heavy-boiling species, these results indicate a considerable conversion of the biodiesel distillation bottoms, which consist of unsaponifiable materials. Example 7: Hydroisomerization of the HDO product from biodiesel distillation bottoms The deoxygenated products from Example 6 were combined and evaluated to determine their low-temperature properties. The cloud point was found to be 26 °C and the pour point was measured to be 21 °C. To improve low-temperature properties for diesel fuel applications, the hydrocarbon was subjected to hydroisomerization. A pilot plant tubular reactor was filled with a bifunctional isomerization catalyst with a silicon-alumina support containing zeolite, which provided the acid functionality, and a Pt / Pd noble metal combination, which provided the hydrogenation-dehydrogenation activity. The reaction parameters are listed in Table 7. Table 7. Hydroisomerization operating conditions of Example 7. Parameter Operating Condition Hourly space velocity of liquid 1.15 h-1 Temperature 594 °F Pressure 990 psig Hydrogen to liquid matter ratio 3,100 SCF / bbl The yield (volume of hydroisomerized diesel per volume of hydroisomerized material) was 97%. The quality parameters selected for the diesel fraction 41 238882 1944035 of 44 hydroisomerized are listed below in Table 8. Table 8. Quality parameters selected for the hydroisomerized diesel fraction of Example 7. Quality Parameter Result Cloud Point -12.5 °C Pour Point -18 °C Freezing Point -10.1 °C Flash Point 85 °C As a result of the high degree of variability in the identity and quantity of unsaponifiable material found in biodiesel feedstocks, particularly the lowest-cost raw materials, a number of process steps, as described in the embodiments of the invention, can be carried out to convert highly impure feedstocks into high-quality, fully acceptable biodiesel and valuable chemicals from the unsaponifiable material. These various embodiments are described in sufficient detail to enable the person skilled in the art to implement the invention, and it is understood that the person skilled in the art may make modifications to the various embodiments described.When the methods and steps described above indicate that certain events occur in a specific order, those skilled in the art will recognize that the order of certain steps can be modified and that such modifications are in accordance with the principles of the invention. Furthermore, certain steps can be carried out simultaneously in a parallel process, as well as sequentially. All publications, patents, and patent applications cited in this descriptive memorandum are incorporated herein in their entirety by reference, as if each publication, patent, or patent application had been specifically and individually filed herein. The embodiments, variations, and figures described above provide an indication of the utility and versatility of the present invention. It is possible to use other embodiments that do not provide all the features and advantages set forth herein without departing from the spirit and scope of the present invention. Such modifications and 42 238882 1944035 of 44 variations are considered within the scope of the principles of the invention, which are defined in the claims. 238882 1944035 of 44 20225952036 CRISTIAN DANIEL BITTEL - 20225952036 Digitally signed by PORTALTRAMITES - INPI Date: 2022.09.05 15:18:38 -03:00 Reason: Digitally Signed by the INPI Location: Buenos Aires, Argentina 1944035

Claims

1. A process for the production of purified biodiesel from a feedstock containing unsaponifiable material, said process being characterized in that it comprises: a. introducing the feedstock into a pretreatment process to produce a pretreated feedstock; b. introducing the pretreated feedstock into an FFA refining process to produce a refined feedstock; c. reacting the refined feedstock in a transesterification reactor with an alcohol to produce crude biodiesel; d. purifying the crude biodiesel to produce purified biodiesel and a biodiesel residue; e. treating the biodiesel residue to recover a biodiesel residue residue, waxes, terpenes, sterols, and sterol esters by: i. treating the biodiesel residue with a first solvent to remove waxes and terpenes by sedimentation and recover a first liquid phase thereof; ii.treating the first liquid phase with a second solvent to recover a biodiesel blend component and a second liquid phase; wherein the first solvent has a lower polarity and a lower molecular weight than the second solvent; and iii. evaporating the first solvent and any remaining second solvent from the second liquid phase to recover the remaining biodiesel residue and a solid or gel sediment comprising the sterols and sterol esters; and f. one of the following steps: i. introducing the remaining biodiesel residue into a biodiesel feedstock or a biodiesel blend component; or ii. blending the remaining biodiesel residue with the purified biodiesel. Seven claims follow.