阅读说明：本技术 生物质基脂质材料的纯化 (Purification of biomass-based lipid materials ) 是由 留卡-佩卡·帕萨宁 亚尔莫·哈尔图宁 安妮卡·马尔姆 瓦艾诺·西波拉 于 2018-12-28 设计创作，主要内容包括：本文提供了一种纯化生物质基脂质材料的方法,包括以下步骤：(a)提供生物质基脂质材料的进料；(c)任选地干燥生物质基脂质材料的进料；(d)在减压下从生物质基脂质材料的进料中除氧；(e)在180至300℃下在减压下热处理生物质基脂质材料的进料,以使包含在生物质基脂质材料中的含磷和/或金属的杂质的至少一部分固化,同时蒸馏出至少一部分包含在生物质基脂质材料中的游离脂肪酸和低分子量氮化合物,以至少获得包含游离脂肪酸和低分子量氮化合物的馏分,以及包含固体形式的降解的含磷和/或金属的杂质的热处理的生物质基脂质材料；和f)从第二馏分中去除固体降解的含磷和/或金属的杂质；从而获得纯化的生物质基脂质材料。(Provided herein is a method of purifying biomass-based lipid material, comprising the steps of: (a) providing a feed of biomass-based lipid material; (c) optionally drying the feed of biomass-based lipid material; (d) removing oxygen from a feed of biomass-based lipid material under reduced pressure; (e) heat treating a feed of biomass-based lipid material at a reduced pressure at 180 to 300 ℃ to solidify at least a portion of the phosphorus and/or metal-containing impurities contained in the biomass-based lipid material while distilling off at least a portion of the free fatty acids and low molecular weight nitrogen compounds contained in the biomass-based lipid material to obtain at least a fraction containing free fatty acids and low molecular weight nitrogen compounds and the heat-treated biomass-based lipid material containing degraded phosphorus and/or metal-containing impurities in solid form; and f) removing solid degraded phosphorus and/or metal containing impurities from the second fraction; thereby obtaining a purified biomass-based lipid material.)

1. A method of purifying biomass-based lipid material, comprising the steps of:

(a) providing a feed of biomass-based lipid material;

(c) drying the feed of biomass-based lipid material;

(d) removing oxygen from the feed of biomass-based lipid material under reduced pressure;

(e) heat treating the feed of biomass-based lipid material at a reduced pressure at 180 to 300 ℃ to solidify at least a portion of the phosphorus and/or metal containing impurities contained in the biomass-based lipid material while distilling off at least a portion of the free fatty acids and low molecular weight nitrogen compounds contained in the biomass-based lipid material,

to obtain at least:

a fraction comprising free fatty acids and low molecular weight nitrogen compounds, and

a heat-treated biomass-based lipid material comprising degraded phosphorus-and/or metal-containing impurities in solid form; and

f) removing solid degraded phosphorus and/or metal containing impurities from the second fraction;

thereby obtaining a purified biomass-based lipid material.

2. The method of claim 1, comprising the steps of:

(a) providing a feed of biomass-based lipid material;

(b) pretreating the feed of biomass-based lipid material;

(c) drying the feed of biomass-based lipid material;

(d) removing oxygen from the feed of biomass-based lipid material under reduced pressure;

(e) heat treating the feed of biomass-based lipid material at a reduced pressure at 180 to 300 ℃ to solidify at least a portion of the phosphorus and/or metal containing impurities contained in the biomass-based lipid material while distilling off at least a portion of the free fatty acids and low molecular weight nitrogen compounds contained in the biomass-based lipid material,

to obtain at least:

a fraction comprising free fatty acids and low molecular weight nitrogen compounds, and

a heat-treated biomass-based lipid material comprising degraded phosphorus-and/or metal-containing impurities in solid form; and

(f) removing solid degraded phosphorus and/or metal containing impurities from the second fraction;

thereby obtaining a purified biomass-based lipid material.

3. The method of claim 1, comprising the steps of:

(a) providing a feed of biomass-based lipid material;

(b) optionally pretreating the feed of biomass-based lipid material;

(c) drying the feed of biomass-based lipid material;

(d) removing oxygen from the feed of biomass-based lipid material under reduced pressure;

(e) heat treating the feed of biomass-based lipid material at a reduced pressure at 180 to 300 ℃ to solidify at least a portion of the phosphorus and/or metal containing impurities contained in the biomass-based lipid material while distilling off at least a portion of the free fatty acids and low molecular weight nitrogen compounds contained in the biomass-based lipid material,

to obtain at least:

a fraction comprising free fatty acids and low molecular weight nitrogen compounds, and

a heat-treated biomass-based lipid material comprising degraded phosphorus-and/or metal-containing impurities in solid form; and

f) removing solid degraded phosphorus and/or metal containing impurities from the second fraction;

thereby obtaining a purified biomass-based lipid material; and

(g) post-treating the purified biomass-based lipid material.

4. The process according to any one of claims 1 to 3, wherein step (e) is carried out at 240 to 280 ℃.

5. The process according to any one of claims 1 to 4, wherein the pressure in step (e) is from 0.01 to 50kPa, preferably from 0.1 to 4 kPa.

6. The process according to any one of claims 1 to 5, wherein the water content of the biomass-based lipid material to be treated in step (e) is below 5 ppm.

7. The process according to any one of claims 1 to 6, wherein step (c) is carried out at any temperature of 80 to 120 ℃ under reduced pressure, preferably 5 to 10 kPa.

8. The process according to any one of claims 1 to 7, wherein step (d) is carried out by heating at any temperature of 80 to 120 ℃ under reduced pressure, preferably 0.2 to 1.5kPa, more preferably 0.2 to 0.5 kPa.

9. The process according to any one of claims 1 to 8, wherein the biomass-based lipid material to be purified comprises iii) a phosphorus content (P) of more than 20ppm, preferably more than 50ppm, more preferably more than 70 ppm.

10. The method of any one of claims 1 to 9, wherein the heat-treated biomass-based lipid material is bleached.

11. The method of any one of claims 1 to 10, wherein the purified biomass-based lipid material is combined with a first fraction comprising free fatty acids and low molecular weight nitrogen compounds prior to catalytic upgrading.

Technical Field

The present invention relates to a method for purifying biomass-based lipid materials, in particular biomass-based lipid materials comprising phospholipids, Free Fatty Acids (FFA) and nitrogen-containing compounds.

Background

Biomass-based lipid materials typically contain phosphorus, nitrogen, and/or metal-containing impurities such as phospholipids, as well as other impurities such as Free Fatty Acids (FFA). These impurities need to be removed prior to the catalytic processing of biomass-based lipid materials into transportation fuels or chemicals to prevent catalyst deactivation and/or plugging during processing. If biomass-based lipid materials are processed by hydrogenation, high concentrations of toxic ammonia may also be produced from nitrogen compounds. In addition, nitrogen compounds can cause NOx emissions in traffic fuels. FFA may cause corrosion of the processing unit.

The refining process generally used prior to the catalytic production of fuels or chemicals employs edible oil refining and is generally divided into chemical refining and physical refining.

Known chemical refining processes include degumming and bleaching. In degumming, the removal of impurities is achieved by changing the solubility of the impurities in the fat using chemicals, usually acids, and by removing the solid matter formed, i.e. the gum. In bleaching, the removal of impurities is achieved by using adsorption on clay.

Known physical refining methods include distillation, also known as deodorization. In deodorization, the removal of free fatty acids and malodorous compounds is achieved in that a given amount of stripping agent (usually steam) is passed through the material in a given period of time to remove volatile free fatty acids and malodorous compounds.

However, these techniques are not fully applicable to the most difficult biomass-based lipid materials, such as animal fats, damaged rapeseed oil (damaged rapeseed oil), used cooking oil (used cooking oil), or algae oil, because the impurities cannot be removed to acceptable levels.

Disclosure of Invention

It is therefore an object of the present invention to provide a method that overcomes the above problems. The object of the invention is achieved by a method which is characterized by the features stated in the independent claim. Some preferred embodiments of the invention are disclosed in the dependent claims.

The present invention is based on the unexpected recognition that when biomass-based lipid material is heated at 180 to 300 ℃ under reduced pressure for a given period of time while distilling off impurities that evaporate under the inducing conditions, the impurity content in the biomass-based lipid material can be reduced to a desired level by a process that effects the simultaneous removal of FFA, phosphorus, nitrogen and metal compounds.

The process allows for the feeding of low quality biomass-based lipid materials as feedstock for processes that produce high quality renewable fuels and/or chemicals.

Drawings

In the following, the invention will be described in more detail by means of preferred embodiments with reference to the accompanying drawings, in which

FIG. 1 illustrates a first exemplary process flow of the present method;

FIG. 2 illustrates a second exemplary process flow of the present method;

fig. 3 shows a third exemplary process flow of the present method.

Detailed Description

The present invention provides a method of purifying biomass-based lipid materials to make them more suitable for catalytic processing.

The term "biomass-based lipid material" refers to fats and/or oils of plant, microbial and/or animal origin. It also refers to any waste stream obtained from processing such oils and/or fats. Typically, fats are solid at room temperature, while oils are liquid at room temperature. The term "biomass-based" means that the source of the material is a plant, microorganism, and/or animal. Biomass can be in unprocessed form (e.g., animal fat), or in processed form (waste edible oil).

Examples of biomass-based lipid materials of the invention include, but are not limited to, tall oil, residual bottoms from tall oil distillation processes, animal-based oils, vegetable or plant-based oils such as palm oil sludge (mud palm oil), waste edible oils, microbial oils, algal oils, free fatty acids, any phosphorus and/or metal containing lipids, oils derived from yeast or mold products, biomass-derived oils, rapeseed oils, canola oils, rapeseed oils (colza oil), tall oils, sunflower oils, soybean oils, sesame oils (hemp oil ), olive oils, linseed oils, cottonseed oils, mustard oils, palm oils, peanut oils, castor oils, coconut oils, animal fats such as mutton tallow, beef tallow, whale fats, recovered edible fats, starting materials produced by genetic engineering, and oils derived from microorganisms (e.g., algae and bacteria) as well as any mixture of the above.

In particular, the biomass-based lipid material is animal fat and/or waste edible oil. It will be appreciated that the waste edible oil may comprise one or more of the above oils, such as, for example, rapeseed oil, canola oil, rapeseed oil, sunflower oil, soybean oil, sesame oil, olive oil, linseed oil, cottonseed oil, mustard oil, palm oil, peanut oil, castor oil, coconut oil and tallow.

Biomass-based lipid materials to be purified by the process of the invention typically contain impurities including: phosphorus, and/or metals in the form of phospholipids, soaps and/or salts. For example, the impurities may be in the form of phosphates or sulphates, iron or organic salts, soaps or phospholipids. For example, the metal impurities that may be present in the biomass-based lipid material are alkali or alkaline earth metals, such as sodium or potassium salts, or magnesium or calcium salts, or any compound of the above metals.

The phosphorus compound present in the biomass-based lipid material is typically a phospholipid. In particular, the phospholipids present in the biomass-based lipid material are one or more of phosphatidylethanolamine, phosphatidylcholine, phosphatidylinositol, phosphatidic acid and phosphatidylethanolamine.

Typically, the biomass-based lipid material to be purified comprises any one or more of:

i) a total metal content of more than 1ppm, in particular more than 10ppm, in particular more than 100ppm, such as an iron content (Fe) of more than 1ppm, in particular more than 10 ppm;

ii) a sodium content (Na) greater than 1 ppm;

iii) a phosphorus content (P) of more than 20ppm, in particular more than 50ppm, in particular more than 70 ppm;

iv) a nitrogen content (N) of greater than 1ppm, in particular greater than 100ppm, in particular greater than 400 ppm;

v) a free fatty acid content (FFA) of greater than 5 wt% of the total weight of the biomass-based lipid material, especially from 8 to 15 wt% of the total weight of the biomass-based lipid material.

In a particular example, the biomass-based lipid material to be purified comprises iii) a phosphorus content (P) of greater than 20ppm, particularly greater than 50ppm, particularly greater than 70ppm, and optionally any one or more of:

i) a total metal content of more than 1ppm, in particular more than 10ppm, in particular more than 100ppm, such as an iron content (Fe) of more than 1ppm, in particular more than 10 ppm;

ii) a sodium content (Na) greater than 1 ppm;

iv) a nitrogen content (N) of greater than 1ppm, in particular greater than 100ppm, in particular greater than 400 ppm;

v) a free fatty acid content (FFA) of greater than 5 wt% of the total weight of the biomass-based lipid material, especially from 8 to 15 wt% of the total weight of the biomass-based lipid material.

In another particular example, the biomass-based lipid material to be purified comprises:

i) the total metal content is more than 300 ppm;

ii) a sodium content (Na) greater than 80 ppm;

iii) a phosphorus content (P) of greater than 80 ppm;

iv) a nitrogen content (N) greater than 500 ppm;

v) a free fatty acid content (FFA) of in particular 8 to 15 wt% of the total weight of the biomass based lipid material.

Accordingly, provided herein is a method of purifying biomass-based lipid material, comprising the steps of:

(a) providing a feed of biomass-based lipid material;

(c) optionally drying the feed of biomass-based lipid material;

(d) removing oxygen from a feed of biomass-based lipid material under reduced pressure;

(e) heat treating a feed of biomass-based lipid material at a reduced pressure at 180 to 300 ℃ to solidify at least a portion of the phosphorus and/or metal-containing impurities contained in the biomass-based lipid material while distilling off at least a portion of free fatty acids and low molecular weight nitrogen compounds contained in the biomass-based lipid material,

to obtain at least:

a fraction comprising free fatty acids and low molecular weight nitrogen compounds, and

a heat-treated biomass-based lipid material comprising degraded phosphorus-containing and ≥ based on solid form

Or impurities of metals; and

(f) removing solid degraded phosphorus and/or metal containing impurities from the second fraction;

thereby obtaining a purified biomass-based lipid material.

In step (e), the biomass-based lipid material is heated to cause a thermal reaction that destroys phosphorus-and metal-containing impurities contained in the biomass-based lipid material, thereby producing a solid material that can subsequently be removed from the heat-treated biomass-based lipid material, for example, by filtration. FFAs present in biomass-based lipid materials can also be esterified with glycerol of mono-or diglycerides, particularly when the biomass-based lipid material is low in water content. This results in less FFA being distilled as a separate fraction. In some cases, FFA can also be converted to oligomers, but this is undesirable. The heat treatment is performed in a distillation apparatus while allowing the feed to distill in the distillation apparatus such that the low boiling point FFA and low molecular weight nitrogen compounds contained in the biomass based lipid material are simultaneously removed from the biomass based lipid material as they distill from the biomass based lipid material.

The heat treatment of step (e) is carried out at any temperature of 180 to 300 ℃. For best results, step (e) is carried out at 240 to 280 ℃. The time during which the biomass-based lipid material is heated and maintained at the desired temperature in step (e), i.e., the residence time, is generally from 1 to 300 minutes, preferably from 5 to 240 minutes, and more preferably from 30 to 90 minutes.

The reduced pressure in step (e) enables distillative fractionation of a first fraction comprising free fatty acids and low molecular weight nitrogen compounds and a bottoms fraction comprising a heat treated biomass-based lipid material comprising degraded phosphorus-and/or metal-containing impurities in solid form. Generally, the pressure in step (e) is from 0.01 to 50kPa, preferably from 0.1 to 4 kPa.

Prior to step (e), the feed of biomass-based lipid material is deoxygenated under reduced pressure. Removing oxygen from the feed of biomass-based lipid material prior to the heat treatment/distillation of step (e) reduces the amount of oligomers that can be formed from FFA during step (e). This is desirable because oligomers can cause catalyst deactivation in the catalytic processing of purified biomass-based lipid materials.

Typically, oxygen removal in step (d) is achieved by heating at any temperature of 80 to 120 ℃ under reduced pressure. The time during which the biomass-based lipid material is heated and maintained at the desired temperature in step (d) (i.e., residence time) is typically from 1 to 60 minutes, preferably from 1 to 30 minutes, more preferably from 1 to 10 minutes.

The reduced pressure in step (d) makes it possible to achieve oxygen removal. Typically, the pressure in step (d) is from 0.2 to 1.5kPa, preferably from 0.2 to 0.5 kPa.

According to the process of the present invention, the water content of the biomass-based lipid material to be treated in step (e) is typically less than or equal to 10000ppm, such as e.g. less than 5000ppm, such as e.g. less than 2000ppm, such as e.g. less than 1500ppm, such as e.g. less than 1000ppm, such as e.g. less than 500ppm, such as e.g. less than 250ppm, such as e.g. less than 100ppm, such as e.g. less than 50ppm, such as e.g. less than 25ppm, such as e.g. less than 10ppm, such as e.g. less than 5ppm, such as e.g. Preferably, the water content of the biomass-based lipid material to be purified is below 5 ppm.

If desired, the biomass-based lipid material to be treated in step (e) may be dried prior to step (e) to substantially reduce the water content of the biomass-based lipid material. The low water content of the biomass-based lipid material reduces hydrolysis of triglycerides present in the biomass-based lipid material to FFA during the process and makes the process more controllable. Furthermore, the presence of water in the fraction containing free fatty acids and low molecular weight nitrogen compounds is undesirable.

Thus, step (e) is carried out under dry conditions. Although steam may be added, e.g. injected, to step (e) for heating purposes, the water needs to be removed immediately due to the process conditions of step (e), in particular the reduced pressure.

Thus, in a first example, the method of the invention comprises the steps of:

(a) providing a feed of biomass-based lipid material;

(c) drying the feed of biomass-based lipid material;

(d) removing oxygen from a feed of biomass-based lipid material under reduced pressure;

(e) heat treating and distilling a feed of biomass-based lipid material as described herein to obtain at least:

a fraction comprising free fatty acids and low molecular weight nitrogen compounds, and

a thermally treated biomass-based lipid material comprising degraded phosphorus-and/or metal-containing impurities in solid form; and

f) removing solid degraded phosphorus and/or metal containing impurities from the second fraction;

thereby obtaining a purified biomass-based lipid material.

For example, steps (c) and (d) may be carried out by (c) first drying a feed of biomass-based lipid material in a heated vessel under a small vacuum (small vacuum). This is usually carried out at any temperature of from 80 to 120 ℃ and usually under reduced pressure of from 5 to 10 kPa. The dry feed of biomass-based lipid material may then be introduced into a distillation apparatus, such as a deodorizer, wherein (d) oxygen is first removed at reduced pressure, typically 0.2 to 1.5kPa, preferably 0.2 to 0.5kPa, typically at any temperature of 80 to 120 ℃.

The deoxygenated and dried feed of biomass-based lipidic material is then subjected to the heat treatment/distillation of step (e) as described herein, preferably in the same distillation apparatus as step (d).

The feed of biomass-based lipid material may also be subjected to one or more pretreatment steps prior to the thermal treatment/distillation of step (e). Suitable pretreatment steps include, but are not limited to, water degumming, acid degumming, filtration and bleaching, in any combination and in any order thereof. These pretreatments result in a reduction in the amount of phosphorus and metals in the feed of biomass-based lipid material.

Thus, in a second example, the method comprises the steps of:

(a) providing a feed of biomass-based lipid material;

(b) pretreating a feed of biomass-based lipid material;

(c) optionally drying the feed of biomass-based lipid material;

(d) removing oxygen from a feed of biomass-based lipid material under reduced pressure;

(e) subjecting a feed of biomass-based lipid material as described herein to heat treatment and distillation to obtain at least:

a fraction comprising free fatty acids and low molecular weight nitrogen compounds, and

a thermally treated biomass-based lipid material comprising degraded phosphorus-and/or metal-containing impurities in solid form; and

(f) removing solid degraded phosphorus and/or metal containing impurities from the second fraction;

thereby obtaining a purified biomass-based lipid material.

After the heat treatment/distillation of step (e), removing solid matter resulting from the heat treatment. Thus, in step (f), the degraded phosphorus and/or metal-containing impurities in solid form are removed from the second fraction comprising the heat-treated biomass-based lipid material comprising the degraded phosphorus and/or metal-containing impurities in solid form.

Removal of the solid matter may be accomplished, for example, by any separation method identified by one skilled in the art as being suitable for separating solid matter from the heat-treated biomass-based lipid material. Suitable examples include, but are not limited to, filtration, centrifugation, and phase separation. It should also be understood that several separation methods may be combined, for example, filtration and centrifugation.

Fig. 1 shows a first exemplary process flow of the method of the present invention.

Referring to fig. 1, a feed of biomass-based lipid material 10 is subjected to a step of removing oxygen 20 from the feed of biomass-based lipid material under reduced pressure. The feed of treated biomass-based lipid material is then subjected to heat treatment and distillation 30 as described herein for step (e) and a bottoms fraction comprising heat-treated biomass-based lipid material 31 (which contains degraded phosphorus-and/or metal-containing impurities in solid form), a fraction 32 comprising free fatty acids and low molecular weight nitrogen compounds, and a tail gas 33 are obtained. The heat-treated biomass-based lipid material 31 (which contains degraded phosphorus-and/or metal-containing impurities in solid form) is subjected to removal of solid impurities, for example, by filtration, to obtain a purified biomass-based lipid material 41 and solid impurities 42. The purified biomass-based lipid material 41 may then be subjected to catalytic upgrading (upgrading) 60.

According to the process of the present invention, the heat treated biomass-based lipid material may be subjected to a further post-treatment step before or after the removal step (f). The removal step (f) may also be combined with other post-treatment steps such as bleaching (i.e. clay adsorption step) to improve the removal of impurities. Higher yield of triglycerides after bleaching can be achieved using the process of the invention compared to the case where the heat treatment/distillation of step (e) is omitted.

Other suitable post-treatment steps that may be employed in accordance with the present invention include, but are not limited to, acid or water degumming and bleaching. Preferably, the heat treated biomass-based lipid material is bleached.

Thus, in a fourth example, the method of the invention comprises the steps of:

(a) providing a feed of biomass-based lipid material;

(b) optionally pretreating a feed of biomass-based lipid material;

(c) optionally drying the feed of biomass-based lipid material;

(d) removing oxygen from a feed of biomass-based lipid material under reduced pressure;

(e) subjecting a feed of biomass-based lipid material as described herein to heat treatment and distillation to obtain at least:

a fraction comprising free fatty acids and low molecular weight nitrogen compounds, and

a thermally treated biomass-based lipid material comprising degraded phosphorus-and/or metal-containing impurities in solid form; and

f) removing solid degraded phosphorus and/or metal containing impurities from the second fraction;

thereby obtaining a purified biomass-based lipid material; and

(g) post-treating the purified biomass-based lipid material.

Fig. 2 shows a second exemplary process flow of the method of the invention.

Referring to fig. 2, the feed of biomass-based lipid material 10 is subjected to a step of removing oxygen 20 from the feed of biomass-based lipid material under reduced pressure. The feed of treated biomass-based lipid material is then subjected to heat treatment and distillation 30 as described herein for step (e) and a bottoms fraction comprising heat-treated biomass-based lipid material 31 (which contains degraded phosphorus-and/or metal-containing impurities in solid form), a fraction 32 comprising free fatty acids and low molecular weight nitrogen compounds, and a tail gas 33 are obtained. The heat-treated biomass-based lipid material 31, which contains degraded phosphorus-and/or metal-containing impurities in solid form, is subjected to removal of solid impurities, for example by filtration, to obtain a purified biomass-based lipid material (41, not shown) and solid impurities 42. The purified biomass-based lipid material is then subjected to bleaching 50 to obtain a purified, bleached biomass-based lipid material 51 and spent bleaching earth 52. The purified and bleached biomass-based lipid material 51 may then be subjected to catalytic upgrading 60.

Biomass-based lipid materials purified according to the methods of the invention typically contain significantly lower FFA and nitrogen content than biomass-based lipid materials prior to purification.

Preferably, the purified biomass-based lipid material comprises less than 5 wt%, particularly less than 1 wt%, more particularly less than 0.1 wt% of FFA based on the total weight of the purified biomass-based lipid material.

Preferably, the purified biomass-based lipid material comprises less than 70%, more preferably less than 60%, even more preferably less than 40% of the nitrogen (N) originally present in the unpurified biomass-based lipid material when compared to the amount of nitrogen (as wt%) for the total weight of the biomass-based lipid material.

After purification of the biomass-based lipid material according to the process of the invention, it may be subjected to further processing, for example, catalytic upgrading. Such catalytic upgrading processes include, but are not limited to, catalytic cracking, thermocatalytic cracking, catalytic hydrotreating, fluidized catalytic cracking, catalytic ketonization, catalytic esterification, or catalytic dehydration. Such processes require that the biomass-based lipid material be sufficiently pure and free of impurities that would otherwise interfere with the catalytic process or poison the catalysts present in the process.

The purified biomass-based lipid material can be combined with a first fraction comprising free fatty acids and low molecular weight nitrogen compounds prior to catalytic upgrading. This increases the yield of the final product. The first fraction comprising free fatty acids and low molecular weight nitrogen compounds may also be used for other purposes, such as combustion to energy or re-esterification with glycerol.

Fig. 3 shows a third exemplary process flow of the present method.

Referring to fig. 3, the feed of biomass-based lipid material 10 is subjected to a step of removing oxygen 20 from the feed of biomass-based lipid material under reduced pressure. The feed of treated biomass-based lipid material is then subjected to heat treatment and distillation 30 as described herein for step (e) and a bottoms fraction comprising heat-treated biomass-based lipid material 31 (which contains degraded phosphorus-and/or metal-containing impurities in solid form), a fraction 32 comprising free fatty acids and low molecular weight nitrogen compounds, and a tail gas 33 are obtained. The heat-treated biomass-based lipid material 31, which contains degraded phosphorus-and/or metal-containing impurities in solid form, is subjected to removal of solid impurities, for example by filtration, to obtain a purified biomass-based lipid material (41, not shown) and solid impurities 42. The purified biomass-based lipid material is then subjected to bleaching 50 to obtain a purified, bleached biomass-based lipid material 51 and spent bleaching earth 52. After the purified and bleached biomass-based lipid material 51 is subjected to pretreatment 70 (e.g., nitrogen removal), it is combined with fractions containing free fatty acids and low molecular weight nitrogen compounds 31. The combined mixture may then be subjected to catalytic upgrading 60.