WO2024132811A1

WO2024132811A1 - A process for demetallization of bio-oil

Info

Publication number: WO2024132811A1
Application number: PCT/EP2023/085717
Authority: WO
Inventors: Anders EDLING HULTGREN
Original assignee: Votion Biorefineries Ab
Priority date: 2022-12-19
Filing date: 2023-12-13
Publication date: 2024-06-27

Abstract

The present invention relates to a process for the demetallization of a bio-oil, the process comprising the steps of - adding sulfuric acid, and/or nitric acid, optionally water, and optionally an organic solvent to a bio-oil to obtain a mixture having a water content of from 1 to 95 wt%; - subjecting the mixture to a temperature of from 130 °C to 190 °C; - removing the aqueous phase to obtain a partially demetallized bio-oil having a total metal content of below 150 ppm; and - repeating the foregoing steps at least once to obtain a demetallized bio-oil; - subjecting the demetallized bio-oil to hydroprocessing using a catalyst comprising NiMo, or Fluid Catalytic Cracking (FCC), or gasification; wherein a demetallized bio-oil is obtained, having a total metal content of less than 20 ppm and a total phosphorous content of less than 5 ppm. The invention also relates to the bio-oil obtained by the method.

Description

A PROCESS FOR DEMETALLIZATION OF BIO-OIL

FIELD OF THE INVENTION

The present invention relates to a process for demetallization of bio-oil and the bio-oil obtained by the process.

TECHNICAL BACKGROUND

A challenge for the production of fuel and chemicals from lignocellulosic biomass materials is the presence of metals that can inhibit or deactivate catalysts used in refining processes such as hydroprocessing. Bio-oils derived from lignocellulosic materials are complex mixtures that differ greatly from traditional vegetable oils that have been processed into fuel, such as hydrogenated vegetable oils. Whereas vegetable oils are primarily composed of fatty acid esters - triacylglycerols, and to a lesser extent, diacylglycerols and monoacylglycerols, bio-oils derived from lignocellulosic raw materials can contain aromatic and naphthenic structures, in addition to fatty acids and fatty acid esters. The amounts of heteroatoms in these bio-oils derived from lignocellulosic materials are also highly variable. A biorefinery needs flexibility to process a variety of feedstocks with seasonal availability, so the process must tolerate a wide range of feed compositions.

In traditional crude oil refineries, hydroprocessing catalyst beds are protected by guard beds that comprise an inert trapping material, hydrodemetallization catalysts, or a combination of both. The higher the metal content in the hydroprocessing feed and/or the longer the time period between catalyst changeouts or catalyst skims, the larger the guard bed needed.

Phosphorus is of particular concern, as it is present in bio-oils in the form of phospholipids and, thus, is more difficult to remove than water-soluble metals. Both phospholipids and phosphorus are known to deactivate hydroprocessing catalysts. Other metals, such as calcium and magnesium, have been reported to be bound to phospholipids. In order to remove phosphorus from bio-oils using an aqueous method, the phospholipids must be decomposed. Decomposition of the phospholipids facilitates removal of phosphorus either through the aqueous phase or through the interface between the two phases.

It is desirable to reduce both the content of phosphorus and metals such as aluminium, calcium, magnesium, manganese, phosphorus, potassium, and sodium of the bio-oil via demetallization prior to hydroprocessing to maximize the time period between catalyst changeouts or catalyst skims and to minimize the volume of guard bed required. Moreover, it is also desirable to reduce the content of phosphorus and metals by a means that allows for hydroprocessing of the entire bio-oil, as opposed to, for example, removal of fractions of the bio-oil containing high levels of metals prior to hydroprocessing.

Other methods for the demetallization of bio-oils have claimed low product phosphorus levels but have not effectively reduced the levels of other metals. For example, the method described in WO 2015/095453 Al was effective for phosphorus but not potassium.

Hence, there is a need for an improved method for demetallization of bio-oils.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a method for demetallization of bio-oil. A further object is to provide a bio-oil with a very low metal content.

The method and the demetallized bio-oil according to the present invention are defined in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 presents simulated distillation of feed and hydroprocessed product, day 11, obtained by gas chromatography. The cumulative weight percentage recovered is presented as a function of the boiling point of the hydrocarbon components of the sample (x-axis: effective temperature; y-axis: cumulative weight percentage recovered). Figure 2 presents simulated distillation of feed bio-oil and product, day 11, obtained by gas chromatography. The area percentage under the chromatography curve is presented as a function of the boiling point of the hydrocarbon components of the sample (x-axis: effective temperature; y-axis: analysis area percentage).

Figure 3 presents the yields of carbon dioxide (CO2) and carbon monoxide (CO) as a function of time-on-stream for different reactors.

Figure 4 presents the yields of different hydroprocessed product fractions: gas, naphtha, middle distillates (jet fuel and diesel), and the fraction boiling above 360 °C as a function of time-on-stream for different reactors.

Figure 5 presents the temperatures at which 95 wt% of the total hydrocarbon product boiled, as determined from simulated distillation (ASTM D2887 extended).

DETAILED DESCRIPTION OF THE INVENTION

In a first aspect, the present invention relates to a process for demetallization of bio-oil, the process comprising the following steps: a) providing a bio-oil; b) adding sulfuric acid and/or nitric acid; c) optionally adding water; d) optionally adding an organic solvent; e) obtaining a mixture of the components of step a) and b), and optionally c) and/or d); f) subjecting the mixture obtained in step e), to a temperature of from 130 °C to 190 °C, during a time period of at least 1 minute; g) optionally adding water; with the proviso that water is added in either or both of steps c) and g), thus providing an aqueous phase; h) optionally adding an organic solvent; i) removing the aqueous phase to obtain a partially demetallized bio-oil having a total metal content of below 150 ppm; j) repeating steps a)-i) at least once; wherein when said steps are repeated, the bio-oil of step a) is instead the partially demetallized bio-oil of step i), to obtain a demetallized oil; k) optionally repeating steps a) and c)-i) at least once, wherein when said steps are repeated, the bio-oil of step a) is instead the demetallized bio-oil of step j), and the temperature in step f) is from 10 °C to 190 °C; to obtain a demetallized biooil; with the proviso that the total treatment time of steps f) and j) and optionally k) is up to 45 minutes, preferably up to 30 minutes, and more preferably up to 25 minutes; l) subjecting the demetallized bio-oil to hydroprocessing using a catalyst comprising NiMo, Fluid Catalytic Cracking (FCC), steam cracking, or gasification; wherein the mixture obtained in step e) has a water content of from 1 to 95 wt%, based on the total weight of the mixture; and wherein the water content prior to removal of the aqueous phase in step i) is from 10 to 90 wt%, preferably from 20 to 80 wt%, wherein a demetallized bio-oil is obtained, having a total metal content of less than 20 ppm, preferably less than 10 ppm, and a total phosphorous content of less than 5 ppm.

The steps a) to f) may be performed in consecutive order. Alternatively, steps a) and b) may be performed in the reverse order. Step d), if present, and step e) have to be performed in said order.

Repeating steps a )-i ) enables further reduction of the total metal content and facilitates efficient phosphorous removal.

Preferably step k) is carried out. Repeating steps a) and c)-i) at least once and thereby omitting the addition of an acid in step b) favours the provision of a demetallized oil that is devoid of acid before being subjected to step I). It is preferred to have an as clean as possible oil prior to hydroprocessing. All aspects and embodiments disclosed herein can be combined with any other aspect and/or embodiment disclosed herein.

In one embodiment, the bio-oil in step a) has a boiling temperature of from 70 °C up to 800 °C. Preferably, at least 10 wt%, more preferably at least 15 wt%, preferably 25wt%, of the bio-oil boils above 440 °C, as determined by simulated distillation.

The bio-oil used in the method according to the present invention is preferably selected from tall oil pitch, crude tall oil, pyrolysis oil, lignin oil, hydrothermal liquefaction oil, turpentine, a bio-oil recycled from a process comprising the method according to the present invention, a liquid stream recycled from a hydroprocessing step of biomass, oil obtained from any one of lignocellulosic material, softwood, hardwood, bagasse, bark, sawdust, other types of forest biomass, grass, algae, seagrass or seaweed, cones, needles, leaves, bark, nutshell, fruit kernel, husk, corn stover, non-animal aquaculture residues, or non-animal agriculture raw material, such as agriculture residues, e.g. straw; or any combination thereof. Vegetable oils and animal residues, including animal fat, are excluded as bio-oil in the process according to the present invention. A reason for excluding vegetable oils is not to compete with resources from food industry. Examples of vegetable oils are a$ai palm oil, avocado oil, Brazil nut oil, buriti oil, canola oil, carapa oil, coconut oil, corn oil, cottonseed oil, grape seed oil, graviola oil, hazelnut oil, hemp seed oil, jambu oil, linseed oil, olive oil, palm oil, palm fatty acid distillate (PFAD), palm oil mill effluent (POME), palm kernel oil, passion fruit oil, peanut oil, pracaxi oil, rapeseed oil, rice bran oil, safflower oil, sesame oil, Solarium oil, soybean oil, sunflower oil, used cooking oil, tucuma oil, and walnut oil.

As used herein, the term "other types of forest biomass" encompasses trees from plantations of any age, including short rotation coppice, and includes all parts of the tree, such as the trunk, including pieces thereof, bark, branches, needles or leaves, cones and roots. Examples of hardwood are the Betulaceae family: such as alder, birch, hazel, hornbeam; Fabaceae family: such as acacia (subfamily mimosoideae); Fagaceae family: such as beech, chestnut, oak; Juglandaceae family: such as hickory, pecan, walnut; Myrtaceae family: such as gum, eucalyptus, angophora; Rosaceae family: such as Prunus genus: cherry; Salicaceae family: such as aspen, cottonwood, poplar, willow; Sapindaceae family: such as maple, buckeye, horse chestnut, and Ulmaceae family: such as elm, zelkova. Examples of softwood are Ginkgoaceae family: ginkgo biloba; and conifers, comprising Araucariaceae family: such as kauri;

Cupressaceae family: such as cypress, juniper, redwood; Pinaceae family: such as cedar, Douglas-fir, fir, hemlock, larch, pine, spruce, tamarack; Podocarpaceae family: such as yellowwood; Taxaceae family: such as yew.

In one embodiment, and organic solvent is added in step d). The organic solvent disperses or dissolves the bio-oil. The organic solvent is preferably selected from a water-insoluble C4-6 alcohol, preferably butanol; ethers, such as methyl tetra hydrofuran; alkyl acetates, such as butyl acetate or ethyl acetate; a liquid stream recycled from a hydroprocessing step, or mixtures thereof. Using a recycled stream lowers the requirement for fresh solvent. Solvents of bio-renewable origin are preferred. Addition of a water-insoluble solvent in step d) can be advantageous for the subsequent removal of the aqueous phase. The solvent aids in the separation of the aqueous phase from the bio-oil. The need for a solvent depends on the miscibility of the bio-oil with water, which can vary widely depending on the composition of the bio-oil. For example, tall oil pitch and crude tall oil are not readily miscible with water, thus, addition of a solvent to such bio-oils is not necessary from a phase separation standpoint. However, a solvent may be desirable for reducing the viscosity of a bio-oil to facilitate transport or mixing. The dissolution of the bio-oil may be performed either before or after the addition of water.

In one embodiment of step b) an excess of sulphuric acid and/or nitric acid is added. The excess amount can be determined by measuring the content of metal ions in the bio-oil before it is demetallized. Preferably, at least 0.5 g concentrated sulphuric acid and/or concentrated nitric acid per 100 g bio-oil is added, more preferably at least 1 g concentrated acid per 100 g bio-oil, even more preferably at least 2 g concentrated acid per 100 g bio-oil, up to a limit of 10 g concentrated acid per 100 g bio-oil. In one embodiment of step b) one or more additional acids are added, preferably selected from mineral acids, e.g., hydrochloric acid; or organic acids, such as citric acid, formic acid, lactic acid, oxalic acid, or acetic acid. The addition of one or more additional acids preferably adjusts the pH of the aqueous phase in the mixture to a pH of 0-6, preferably a pH of 0-4, more preferably a pH of 0-2. Most preferably the pH is less than 1. In an alternative embodiment, the addition of the one or more acids adjusts the pH of the aqueous phase in the mixture to a pH of 1-4, preferably 1-2.

The bio-oil of step a) and the acid added in step b), the water optionally added in step c), and the solvent optionally added in step d) may be mixed by any suitable mixing method to obtain the mixture of step e).

The present method allows a large amount of water to be present in the mixture when it is heated in step f). The mixture may have a water content of from 1 to 95 wt%, preferably from 10 to 90 wt%, based on the total weight of the mixture; more preferably 15-75 wt%, and even more preferably 20-60 wt%. Increasing the water content improves the removal of metals from the bio-oil. Alternatively, repeating the steps without increasing the water content can also improve the removal of metals.

The desired temperature in step f) may be reached by using pre-heated bio-oil, and/or pre-heated liquid(s), from any of the previous steps a) to d); or by direct heating of the mixture obtained in step e). When the content of any one of step a) to d) is pre-heated prior to obtaining the mixture in step e), said mixture is obtained at a time point when said content is still warm or hot. When step f) is carried out for the first time, the temperature is from 130 °C to 190 °C; preferably from 150 °C to 180 °C; more preferably from 155 °C to 175 °C. This temperature is required for effective decomposition of the phospholipids and subsequent phosphorus removal. However, when step f) is repeated, the phospholipids have already been decomposed and lower temperatures may be used, such as from 10 °C to 190 °C, preferably from 10 °C to 180 °C, more preferably from 10 °C to 150 °C. The temperature used depends on the composition of the bio-oil, whereby the temperature used shall be sufficient for phase separation. Too high temperatures favour the formation of emulsions. When the biomass does not contain phospholipids, lower temperatures, such as from 10 °C to 190 °C, preferably from 10 °C to 180 °C, more preferably from 10 °C to 175 °C may be used already the first time step f) is carried out.

A higher temperature, within the interval, facilitates a lower content of phosphorus in the obtained demetallized bio-oil. However, if the temperature is too high, e.g., above 200 °C, the separation of the organic and aqueous phases becomes more difficult due to increasing emulsification. Additionally, temperatures below 200 °C are preferred to avoid excess energy usage in the form of heat input beyond that required for an efficient phase separation. When steps are repeated, lower temperatures may be used in subsequent repetitions than originally used.

The choice of suitable temperature also depends on the viscosity of the bio-oil. Heavy bio-oils with high viscosities require higher temperatures than lighter bio-oils to achieve effective mixing and, subsequently, an efficient phase separation. For example, when step f) is repeated, temperatures greater than 100 °C are preferred when the bio-oil is a high viscosity oil, such as tall oil pitch, whereas temperatures below 100 °C are sufficient for lower-viscosity oils. The use of a solvent can be advantageous for certain heavy biooils, such as lignin oil, to decrease the viscosity without a need for increasing the temperature.

In one embodiment, wherein steps a) and c)-i) are repeated at least once and wherein the bio-oil of step a) is instead the demetallized bio-oil of step j), the temperature in step f) is from 90 °C to 180 °C, preferably from 100 to 180 °C.

The mixture in step f) may be subjected to the desired temperature gradually, continuously, or in several stages over a period of time. The time required for heating depends on the rate of heating and the thoroughness of mixing. The mixture is subjected to the desired temperature for a period of at least 1 minute, preferably at least 5 minutes. In one embodiment, the mixture is subjected to the desired temperature for a period of 1 to 15 minutes. Sufficient heating and residence time makes the bio-oil less viscous, thus facilitating the diffusion of metal ions to the aqueous phase.

In one embodiment, at least one organic solvent is added in step d) and/or h). In a further embodiment, said solvent is removed from the bio-oil, at least partially, prior to hydroprocessing in step I) and is recycled back to step d) and/or h). The solvent may be removed by conventional methods, for example by evaporation or solvent extraction. However, letting a certain amount of organic solvent joining the bio-oil to the hydroprocessing step (e.g. up to 20% of the oil weight) may improve feeding of the biooil.

In one embodiment, the aqueous phase removed in step i) is allowed to phase separate from remaining bio-oil, whereupon the remaining bio-oil is recycled back to step a). The time required for phase separation depends on the temperature of the mixture, the composition of the mixture, the optional addition of an emulsion breaker, and the process equipment used. Phase separation can be carried out in a batch or continuous process. In a batch process, the removed aqueous phase can be allowed to phase separate in a separate container. In a continuous process using a decanter, for example, the mixture is continuously fed to the decanter, while an aqueous stream and an organic stream are continuously removed from the decanter.

Removal of the aqueous phase from the bio-oil is critical for the removal of metals from the bio-oil, as the metals are partitioned into the aqueous phase. Poor phase separation thereby results in poor demetallization performance. Removal of the aqueous phase by evaporation does not facilitate demetallization, as the metals are not removed with the water. Removal of the aqueous phase can be facilitated by the use of mechanical means, such as a centrifuge, decanter, decanter centrifuge, coalescer, electrostatic coalescer, oil desalter, API (American Petroleum Institute) separator, rotating separator, or by any combination of these; electrical means, such as electrostatic desalting units; chemical means, such as addition of an emulsion breaker; or by a combination of these means. Suitable emulsion breakers, also known as demulsifiers, are selected from amines, such as octylamine or dioctylamine; alcohols, such as ethanol or long-chain alcohols; polyhydric alcohols, such as propylene glycol or polyethylene glycol; fatty acid alkoxylates; oxyalkylated alkyl phenols; oxyalkylated alkyl resins; sulfonates; other nonionic surfactants comprising both hydrophilic and hydrophobic groups; or combinations thereof. The removal of the aqueous phase in the method disclosed herein does not involve the use of enzymes.

When removal of the aqueous phase is facilitated by the use of mechanical means, the need for the addition of solvent or for repeating the washing steps may be eliminated, due to the effectiveness of the phase separation resulting in efficient removal of metals.

In one embodiment, mechanical means, electrical means, or chemical means, or any combination of these, is used for removing the aqueous phase before the first repetition of steps a) to i). In one embodiment, mechanical means, electrical means, or chemical means, or any combination of these, is used for removing the aqueous phase in step i) or in step k) and before carrying out step I).

In one embodiment, removal of the aqueous phase in step i) is carried out by decanting. After decanting, residual water containing metals may be removed from the partially demetallized bio-oil by further mechanical means, electrical means, or chemical means, or any combination of these. Thus, in one embodiment, removal of the aqueous phase proceeds in two steps, the first step constituting the removal of the aqueous phase by mechanical means, such as decanting, and the second step constituting removal of residual water from the partially demetallized bio-oil by further mechanical means, electrical means, or chemical means, or any combination of these. In embodiments, the residual water is removed from the demetallized bio-oil by any one of distillation, evaporation, membrane separation, or by liquid-liquid extraction. Residual water, when present, may be thus removed from the demetallized bio-oil obtained in step j) or step k). Preferably, after removal of the aqueous phase by decanting, the partially demetallized bio-oil is subjected to centrifugation to remove the remaining water. The obtained demetallized bio-oil preferably has a water content of less than 10 wt%, more preferably of from 0.01 to 5 wt%, most preferably 0.01 to 1 wt%.

Repeating steps a)-i) enables further reduction of the total metal content, including further phosphorous removal. In one embodiment, an acid is added in the first and second instance of step b) and when further repeated, step b) is omitted. Using water without acid in the final repetition of steps a)-i) reduces the corrosivity of the demetallized bio-oil in downstream processing. Addition of a base to the demetallized bio-oil is not desirable, as this would result in the addition of metals, nitrogen compounds, or other species that are hydroprocessing catalyst inhibitors or catalyst poisons.

The aqueous phase obtained in step g) may be demineralized and/or extracted with an organic solvent in step h) to separate organic compounds from the aqueous phase. The water added in step c) may be demineralized water, including distilled water; or the aqueous phase recycled from step i). Recycling the aqueous phase may be performed to reduce the need for demineralized water, wherein recycled water is used the first time step c) is performed, and fresh water is used when step c) is repeated, at least once. Using demineralized waterthe last time step c) is performed ensures that no metals are introduced into the bio-oil from the wash water.

In one embodiment of the method the obtained demetallized bio-oil has a total metal content of less than 20 ppm, preferably of from 0 to 10 ppm, more preferably of from 0.01 to 10 ppm. As used herein the total metal content refers to the content of metals selected from aluminium, calcium, magnesium, manganese, phosphorus, potassium, and sodium. The person skilled in the art realizes that the method can be used also for reducing the content of other metals than those specifically disclosed herein. In one embodiment, the demetallized bio-oil has a total phosphorous content of less than 10 ppm, preferably of from 0 to 5 ppm, more preferably of from 0.01 to 5 ppm. A bio-oil with a phosphorous content below 5 ppm and a total metal content below 10 ppm may advantageously be the subject for hydroprocessing. In one embodiment, the demetallized bio-oil undergoes hydroprocessing into fuel and/or chemicals. Hydroprocessing of the bio-oil may comprise passing the bio-oil through a guard bed, followed by hydrotreating and optionally, mild hydrocracking and/or hydrodewaxing, followed by hydrofinishing the bio-oil with various catalysts. Fractionation is performed to obtain the hydroprocessed fuel and/or chemicals. Hydroprocessing, hydrotreatment, hydrocracking, hydrodewaxing, hydrofinishing and fractionation are concepts well known to the skilled person. In a preferred embodiment, the demetallized bio-oil undergoes hydroprocessing using NiMo and NiW catalysts.

In a second aspect, the present invention also relates to a bio-oil obtained by the method disclosed herein.

In a third aspect, the present invention relates to a bio-oil having a total metal content of less than 20 ppm, preferably of from 0 to 20 ppm, more preferably of from 0 to 10 ppm, or from 0.01 to 10 ppm; and a total phosphorous content of less than 5 ppm, preferably of from 0 to 5 ppm, or from 0.01 to 5 ppm.

In a fourth aspect of the invention, the demetallized bio-oil is subjected to hydroprocessing comprising the following steps:

/. subjecting the demetallized bio-oil to a hydrogen atmosphere in a first zone comprising a guard bed or a hydroprocessing bed; any or both of which comprising a NiMo hydroprocessing catalyst, at a temperature of from 200 °C to 380 °C, preferably of from 250 °C to 350 °C;

//. in a second zone, subjecting the bio-oil to hydroprocessing under hydrogen atmosphere with hydroprocessing cata lyst(s) comprising NiMo at a temperature of from 200 °C to 380 °C, preferably from 300 °C to 350 °C, at a pressure of from 60 to 200 bar, preferably from 80 to 180 bar, more preferably from 100 to 160 bar, and a gas-to-oil ratio of from 1500 to 2500 Nm³ H2:m³ total liquid; Hi. optionally subjecting the hydroprocessed bio-oil to fractionation; iv. in a third zone, subjecting the hydroprocessed bio-oil, or fractions from the optionally subsequently fractionated hydroprocessed bio-oil, to hydroprocessing under hydrogen atmosphere using hydroprocessing catalysts comprising NiMo, and any or both of the hydroprocessing catalysts NiO and NiW, at a temperature from 350 °C to 425 °C, preferably 360 °C to 390 °C, at a pressure of from 60 to 200 bar, preferably from 80 to 180 bar, more preferably from 100 to 160 bar, and a gas-to-oil ratio of from 1500 to 2500 Nm³ H2:m³ total liquid; to attain hydrodeoxygenation, and one or more of hydrodewaxing, selective ring-opening, and hydrocracking, preferably all three of the latter, to obtain a hydroprocessed bio-oil; v. optionally, in a fourth zone, subjecting the hydroprocessed bio-oil obtained in step /v to a hydrofinishing catalyst comprising NiMo under hydrogen atmosphere; and vi. optionally subjecting the hydroprocessed or hydrofinished bio-oil to fractionation, wherein fractionation is carried out in at least one of steps Hi and vi.

The method according to the fourth aspect of the invention may be further characterized by a total CO yield of less than 1 wt% and preferably less than 0.2 wt%; and a total CO2 yield of less than 1 wt% and preferably less than 0.2 wt%, as calculated on the demetallized bio-oil.

EXAMPLES - DEMETALLIZATION

Three different feedstocks; crude tall oil, tall oil pitch, and bark oil, were used as bio-oil in the following examples.

Example 1: Water as solvent

1. Bio-oil (100 mL) was added to an autoclave.

2. An equal volume of sulphuric acid in water (pH 1) was added to the bio-oil.

3. The mixture was stirred while heated to a temperature of about 170 °C. 4. After the target temperature was reached, the stirring was turned off, and the two phases were given 30 minutes to separate.

5. After the contents from the autoclave had cooled to 90 °C, for ease of handling, an aqueous phase and an oil phase were collected.

Example 2: Solvent-assisted separation

1. Bio-oil (100 mL) was added to an autoclave.

2. An equal volume of acid in water (pH 1) was added to the bio-oil.

3. The mixture was stirred while heated to a temperature of about 170 °C.

4. After the targeted temperature was reached, the stirring was turned off, and the two phases were given 30 minutes to separate.

5. After the contents from the autoclave had cooled to 90 °C, for ease of handling, the contents were transferred to a separation funnel. 50 mL of butanol and 50 mL of 2- methyl tetra hydrofuran (2-methyl THF) were added to the bio-oil sample.

6. An aqueous phase and an oil phase were collected.

7. The water and solvent were boiled off, leaving the oil.

Example 3: Use of separation aid - emulsion breaker

1. Bio-oil (100 mL) was added to an autoclave.

2. An equal volume of acid in water (pH 1) was added to the bio-oil.

3. The mixture was stirred while heated to a temperature of about 170 °C

4. After the target temperature was reached, the stirring was turned off, and the two phases were given 30 minutes to separate.

5. After the contents from the autoclave had cooled to 90 °C, for ease of handling, the contents were transferred to a separation funnel and the aqueous phase was removed.

6. An emulsion breaker (Solenis PSA1142) was added to the oil phase whereby the oil phase separated into an aqueous phase and an oil phase.

7. The aqueous phase and the oil phase were collected. Example 4: Use of separation aid - centrifugation

1. Bio-oil (100 mL) was added to an autoclave.

2. An equal volume of acid in water (pH 1) was added to the bio-oil.

3. The mixture was stirred while heated to a temperature of about 170 °C.

5. After the contents from the autoclave had cooled to 90 °C, for ease of handling, the contents were transferred to a separation funnel.

6. The oil phase was collected and centrifuged.

7. The centrifuged oil was then decanted.

Example 5: Comparative example - lower temperature

The procedure of Example 1 was repeated but the mixture was heated to a temperature of about 115 °C.

Example 6: Comparative example - no acid

The procedure of Example 1 was repeated but water (pH 7) was used instead of aqueous sulphuric acid.

RESULTS

Metal content was analyzed using inductively coupled plasma mass spectroscopy (ICP SCAN CM-38). The content of certain metals and phosphorus is presented in Tables 1 and 2.

Table 1: Metal analyses of crude tall oil (CTO) and treated products

Table 2: Metal analyses of tall oil pitch (TOP), bark oil, and products treated according to Example 1

5

• The three different feedstocks, crude tall oil, tall oil pitch, and bark oil, were successfully demetallized.

• For the feedstocks used, acid was required for sufficient removal of metals; washing with pH 7 water in the comparative example resulted in poor metals removal, as 0 well as poor separation of the aqueous and oil phases.

• High temperature gives a faster separation and better removal of metals. The comparative example performed at a lower temperature removed a portion of the metals but was less effective than using a higher temperature and did not sufficiently reduce the content of phosphorus, calcium, or sodium. 5 • The phosphorus content was reduced to levels of less than 3 ppm. Successful reduction of phosphorus level in the feedstocks used required both acid and elevated temperature, as shown by the comparative examples.

• Centrifugation was seen to be effective in further reduction of the total metal content. • Washing with solvents, butanol, and 2-methyl THF, was shown to be effective, but not required. However, the addition of butanol resulted in a slower separation of phases.

EXAMPLES - HYDROPROCESSING

Materials and methods

Reactors

Hydroprocessing tests were run in five parallel reactors, each reactor with its own catalyst configuration. Each reactor consisted of two packed beds in series without interstage separation.

Bed 1 comprised zones 1 & 2, containing a guard bed and hydroprocessing catalysts.

Bed 2 comprised zone 3, comprising hydrodewaxing and hydrocracking catalysts.

Zone 4 was not included in the examples; the primary difference expected if hydrofinishing had been included would be a lower olefin content of the product.

As there were no sample points between Bed 1 and Bed 2, in order to sample the Bed

1 effluent, duplicates of Bed 1 were run in parallel.

Catalysts

Commercial catalysts from different vendors were used in both layers and physical mixtures within the reactors.

• Catalysts selected from: NiMo, NiO, and NiW Supports selected from: alumina, zeolite

Silicon carbide was used as inert packing material at the inlet and outlet of each bed

Feedstock

Demetallized crude tall oil was washed with acid, then demineralized water, then stripped to remove water and filtered to remove particulates. Feed to the reactors:

¹¹ Said value is seemingly high, which was due to technical limitations in heating during demetallization. Heating to a temperature of at least 130°C is required to reach adequate demetallization.

Process conditions

The oil feed was contacted with the fresh H2 feed prior to introduction into the first reactor. The reactors were operated isothermally (± 1 °C) in upflow mode. The reactor effluent was routed to a condenser to separate the gaseous products and unconverted hydrogen from the liquid product.

Characterization

The effluent from each reactor was routed to a condenser, from which the gas phase was routed to an online gas chromatograph for analysis, and the liquid phase was collected and analyzed offline using gas chromatography (GC).

The boiling point distribution of the feed bio-oil (Figures 1 and 2) was determined through simulated distillation by gas chromatography according to the method EN 15199-1, and the product from one of the reactors on day 11 (Figures 1 and 2) according to the ASTM D2887 extended method, calculating the percentage distilled as a function of temperature.

RESULTS - HYDROPROCESSING

The five reactors ran continuously for 11 days without interruption or signs of deactivation. All liquid products were clear and bright, as well as colourless.

Product component yields were calculated as weight percentages of the total feed for each reactor, comprising Bed 1 and Bed 2 in series, based on the GC data. The water yields ranged from 8 wt%to 16wt%. The primary gaseous product was methane, ranging from 1.4 wt% to 1.7 wt% of the total yield. Carbon monoxide (CO) yields ranged from 0.06 wt% to 0.12 wt% of the total yield. Carbon dioxide (CO2) yields ranged from 0 wt% to 0.03 wt%. CO and CO2 yields are shown as a function of time on stream for the different reactors in Figure 3. The proportion of the total hydrocarbon product boiling above 360 °C as a weight percentage of the total product (gas and liquid) was calculated from the GC data. This fraction ranged from 2.3 wt% to 15.7 wt% among the five reactors over the 11-day period. This fraction boiling above 360 °C decreased when the reactor temperature was increased. The different fractions of the total product as a function of time on stream are shown in Figure 4, comprising gas, naphtha, middle distillates (jet fuel and diesel), and the fraction boiling above 360 °C.

The temperatures at which 95 wt% of the total hydrocarbon product boiled, were below 500 °C, as determined from simulated distillation (ASTM D2887 extended), presented in Figure 5.

For all reactors, hydrogen consumption was approximately 20% of the hydrogen fed. Complete hydrodesulfurization and hydrodenitrogenation were observed to occur in the first bed for all reactors, as the total liquid product sulphur was less than 0.5 ppm and the total liquid nitrogen product was below the detection limit.

These results show that the product from all reactors had low CO and CO2 yields and that these results can be attained with a variety of commercial catalysts selected in accordance with the method of the present invention. Additionally, it has been shown that an interstage gas separation is not required, but optional.

Claims

1. A process for demetallization of bio-oil, the process comprising the following steps: a) Providing a bio-oil; b) adding sulfuric acid, and/or nitric acid c) optionally adding water; d) optionally adding an organic solvent; e) obtaining a mixture of the components of step a) and b), and optionally c) and/or d); f) subjecting the mixture obtained in step e), to a temperature of from 130 °C to 190 °C, during a time period of at least 1 minute; g) optionally adding water; with the proviso that water is added in either or both of steps c) and g), thus providing an aqueous phase; h) optionally adding organic solvent; i) removing the aqueous phase to obtain a partially demetallized bio-oil having a total metal content of below 150 ppm; j) repeating steps a )-i ) at least once, wherein when said steps are repeated, the bio-oil of step a) is the partially demetallized bio-oil of step i), to obtain a demetallized bio-oil; k) optionally repeating steps a) and c)-i) at least once, wherein when said steps are repeated, the bio-oil of step a) is instead the demetallized biooil of step j), and the temperature in step f) is from 10 °C to 190 °C; to obtain a demetallized bio-oil; with the proviso that the total treatment time of steps f) and j) and optionally k) is up to 45 minutes, preferably up to 30 minutes, and more preferably up to 25 minutes; l) subjecting the demetallized bio-oil to hydroprocessing using a catalyst comprising NiMo, Fluid Catalytic Cracking (FCC), steam cracking, or gasification; wherein the mixture obtained in step e) has a water content of from 1 to 95 wt%, based on the total weight of the mixture; and wherein the water content prior to removal of the aqueous phase in step i) is from 10 to 90 wt%, preferably from 20 to 80 wt%, wherein a demetallized bio-oil is obtained, having a total metal content of less than 20 ppm, preferably less than 10 ppm, and a total phosphorous content of less than 5 ppm.

2. The process according to claim 1, wherein the bio-oil provided in step a) has a boiling temperature of from 70 °C up to 800 °C, and at least 15 wt%, preferably 25wt%, of the bio-oil boils above 440 °C.

3. The process according to claim 1 or 2, wherein the bio-oil is selected from a tall oil pitch, crude tall oil, pyrolysis oil, lignin oil, hydrothermal liquefaction oil, turpentine, bio-oil recycled from a process comprising the method according to the present invention, a liquid stream recycled from a hydroprocessing step of biomass, oil obtained from any one of lignocellulosic material, softwood, hardwood, bagasse, bark, sawdust, other types of forest biomass, grass, algae, seagrass or seaweed, cones, needles, leaves, bark, nutshell, fruit kernel, husk, corn stover, non-animal aquaculture residues, or non-animal agriculture raw material, such as agriculture residues, e.g. straw; or combinations thereof.

4. The process according to any of the above claims, wherein the bio-oil is not vegetable oil, palm fatty acid distillate (PFAD), palm oil mill effluent (POME), used cooking oil (UCO), or animal fat.

5. The process according to any one of claims 1-4, wherein an organic solvent is added in step d), wherein the organic solvent is selected from a water-insoluble C4-6 alcohol, preferably butanol; ethers, such as methyl tetrahydrofuran; alkyl acetates, such as butyl acetate or ethyl acetate; a liquid stream recycled from a hydroprocessing step, or mixtures thereof.

6. The process according to any one of claims 1-5, wherein an excess of sulphuric acid and/or nitric acid is added in step b).

7. The process according to any one of the previous claims, wherein in step b) at least 0.5 g concentrated acid per 100 g bio-oil is added, preferably at least 1 g concentrated acid per 100 g bio-oil, more preferably at least 2 g concentrated acid per 100 g bio-oil, up to a limit of 10 g concentrated acid per 100 g bio-oil.

8. The process according to any one of claims 1-7, wherein in step b) one or more additional acids are added, preferably selected from mineral acid, e.g. hydrochloric acid; or organic acid, such as acetic acid.

9. The process according to claim 8, whereby the addition of the one or more acids adjusts the pH of the aqueous phase in the mixture to a pH of 0-6, preferably a pH of 0-4, more preferably a pH of 0-2, most preferably the pH is less than 1.

10. The method according to any one of claims 1-9, wherein in step f) the mixture is subjected to a temperature of from 150 °C to 180°C, preferably a temperature of from 155 °C to 175°C.

11. The method according to any one of the previous claims, wherein step k) is carried out.

12. The method according to any one of the previous claims, wherein steps a) and c)-i) are repeated at least once, wherein the bio-oil of step a) is instead the demetallized bio-oil of step j) and wherein the temperature in step f) is from 90 °C to 180 °C.

13. The method according to any one of the previous claims, wherein the aqueous phase is removed by using mechanical means, electrical means, or chemical means, or any combination of these.

14. The method according to claim 13, wherein the mechanical means is selected from a centrifuge, decanter, decanter centrifuge, coalescer, electrostatic coalescer, oil desalter, API (American Petroleum Institute) separator, rotating separator, or by any combination of these; wherein the electrical means is an electrostatic desalting unit; and wherein the chemical means constitutes the addition of an emulsion breaker.

15. The method according to claim 13 or 14, wherein any one of said means is used for removing the aqueous phase before the first repetition of steps a) to i).

16. The method according to claim 13 or 14, wherein any one of said means is used for removing the aqueous phase in step i) or in step k) and before carrying out step I).

17. The method according to any one of the previous claims, wherein removal of the aqueous phase in step i) is carried out by decanting.

18. The method according to claim 17, wherein removal of the aqueous phase proceeds in two steps, the first step constituting the removal of the aqueous phase according to claim 17, and the second step constituting removing residual water from the partially demetallized bio-oil by mechanical means, electrical means, or chemical means, or any combination of these.

19. The method according to any one of the previous claims, wherein the aqueous phase obtained in step i) is demineralized and/or extracted with an organic solvent to separate organic compounds from the aqueous phase.

20. The method according to any one of the previous claims, wherein the water added in step c) is demineralized water, or the aqueous phase recycled from step i).

21. The method according to any one of the previous claims, wherein the aqueous phase removed in step i) is allowed to phase separate from remaining bio-oil, whereupon the bio-oil is recycled back to step a).

22. The method according to any one of the previous claims, wherein the obtained demetallized bio-oil has a water content of less than 10 wt%, preferably of from 0.01 to 5 wt%, more preferably 0.01 to 1 wt%.

23. The method according to any one of the previous claims, wherein at least one organic solvent is added in step d) and/or h), and wherein said solvent is removed from the bio-oil, at least partially, prior to hydroprocessing in step I) and recycled back to step d) and/or h).

24. The method according to any one of the previous claims, wherein the demetallized bio-oil undergoes hydroprocessing using NiMo and NiW catalysts.

25. The method according to any one of the previous claims, wherein the demetallized bio-oil has a total metal content of from 0 to 10 ppm, or of from 0.01 to 10 ppm.

26. The method according to any one of the previous claims, wherein the demetallized bio-oil has a total phosphorous content of from 0 to 5 ppm, or of from 0.01 to 5 ppm.

27. A method according to any of the preceding claims, characterized in that demetallized bio-oil is subjected to hydroprocessing comprising the following steps:

//. in a second zone, subjecting the bio-oil to hydroprocessing under hydrogen atmosphere with hydroprocessing cata lyst(s) comprising NiMo at a temperature of from 200 °C to 380 °C, preferably from 300 °C to 350 °C, at a pressure of from 60 to 200 bar, preferably from 80 to 180 bar, more preferably from 100 to 160 bar, and a gas-to-oil ratio of from 1500 to 2500 Nm³ H2:m³ total liquid;

Hi. optionally subjecting the hydroprocessed bio-oil to fractionation; iv. in a third zone, subjecting the hydroprocessed bio-oil, or fractions from the optionally subsequently fractionated hydroprocessed bio-oil, to hydroprocessing under hydrogen atmosphere using hydroprocessing catalysts comprising NiMo, and any or both of the hydroprocessing catalysts NiO and NiW, at a temperature from 350 °C to 425 °C, preferably 360 °C to 390 °C, at a pressure of from 60 to 200 bar, preferably from 80 to 180 bar, more preferably from 100 to 160 bar, and a gas-to-oil ratio of from 1500 to 2500 Nm³ H2:m³ total liquid; to attain hydrodeoxygenation, and one or more of hydrodewaxing, selective ring-opening, and hydrocracking, preferably all three of the latter, to obtain a hydroprocessed bio-oil ; v. optionally, in a fourth zone, subjecting the hydroprocessed bio-oil obtained in step /v to a hydrofinishing catalyst comprising NiMo under hydrogen atmosphere; and vi. optionally subjecting the hydroprocessed or hydrofinished bio-oil to fractionation, wherein fractionation is carried out in at least one of steps Hi and vi.

28. Method according to claim 27, wherein the total CO yield is less than 1 wt% and preferably less than 0.2 wt%; and wherein the total CO2 yield is less than 1 wt% and preferably less than 0.2 wt%, as calculated on the demetallized bio-oil.

29. A bio-oil obtainable by the method according to any one of the previous claims.

30. A bio-oil having a total metal content of less than 20 ppm, preferably of from 0 to 20 ppm, more preferably of from 0 to 10 ppm, or from 0.01 to 10 ppm; and a total phosphorous content of less than 5 ppm, preferably of from 0 to 5 ppm, or from 0.01 to 5 ppm.