WO2025073572A1

WO2025073572A1 - A process for purifying a bio-oil

Info

Publication number: WO2025073572A1
Application number: PCT/EP2024/077078
Authority: WO
Inventors: Oliver PILARSKI; Armin Lange De Oliveira; Gisela Hieber; Daniel KOEPKE; Monica Haag; Mathias Feyen; Michael Schreiber; Andreas Melzer; Steffen Mueller; Felix HUELSMANN
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2023-10-06
Filing date: 2024-09-26
Publication date: 2025-04-10
Anticipated expiration: 2026-04-06
Also published as: TW202532625A

Abstract

A process for purifying a bio-oil The present invention relates to a process for purifying a bio-oil and a unit for carrying out said process. The present invention further relates to a purified bio-oil obtainable or obtained by said process.

Description

A process for purifying a bio-oil

The present invention relates to a process for purifying a bio-oil and a unit for carrying out said process. The present invention further relates to a purified bio-oil obtainable or obtained by said process.

Bio-oils obtained from different types of biomass are gaining increasing importance as renewable feedstocks for industrial as well as for fuel applications. An important technique for producing bio-oils is pyrolysis of biomass, which is a thermal degradation in an inert atmosphere

Bio-oils obtained from pyrolysis or other processes, if not purified, can damage containers made of steel, especially containers made of carbon-steels and low-alloyed steels, that are used as means for storing, transporting, directing, or handling a bio-oil, by corrosion. Therefore, a purified high-quality bio-oil is preferred as a feedstock to prevent corrosion problems during storage and in downstream refinery processes.

US 2021/0277324 A1 discloses the purification of a pyrolysis oil by treating the oil with sodium hydroxide at a temperature of 240 °C. WO 2014/165859 A1 discloses a method for purifying a pyrolysis oil by reducing contaminants content such as acids, metals. Further, WO 2020/178599 A1 discloses a process for upgrading a pyrolysis oil comprising washing with water the pyrolysis oil, followed by washing the pyrolysis oil with an alkane and treating the obtained organic phase with an upgrading solution comprising polar organic solvent.

However, there is still a need to provide improved process for purifying bio-oils obtained from biomass. In particular, there is still a need to provide improved processes which permit to reduce the corrosion in the downstream processes and/or storage.

Therefore, there is a need to provide a process for purifying bio-oils, in particular by reducing the total acid number as well as oxygen content. Indeed, there is a need to provide high value purified bio-oils while using an economic process.

Therefore, the present invention relates to a process for purifying a bio-oil, the process comprising:

(I) providing a stream F0 comprising a bio-oil;

(ii) subjecting the stream F0 provided in (I) to extraction in at least one extraction zone ZE, obtaining a stream F1 comprising the extracted bio-oil, wherein (ii) comprises:

(11.1) introducing F0 into an extraction unit UM1 comprised in ZE;

(11.2) bringing in contact F0 with water and a base B in UM1 at a temperature T1 in the range of from 10 to 200 °C, obtaining a mixture M1 comprising an aqueous phase P_A(1) and an organic phase Po(1 ), the pH of the aqueous phase P_A(1) of M1 being in the range of from 7.5 to 11;

(11.3) passing the mixture M1 obtained according to (ii.2) into a liquid-liquid separation unit US1 comprised in Z_E, US1 being located downstream of UM1, obtaining a stream F_A(1) comprising P_A(1) and a stream F1 comprising Po(1) being the extracted bio-oil;

(11.4) removing F1 from ZE; (iii) subjecting the stream F1 provided in (ii) to washing in at least one washing zone Zw, Zw being located downstream of ZE, obtaining a stream F2 comprising the purified bio-oil; and optionally

(v) introducing F2 comprising the bio-oil obtained according to (iii) into at least one storage unit SU and storing said bio-oil in SU.

Generally, from 1 to 100 weight-% or from 5 to 100 weight-% or from 10 to 100 weight-% or from 20 to 100 weight-% or from 30 to 100 weight-% or from 40 to 100 weight-% or from 50 to 100 weight-% or from 60 to 100 weight-% or from 70 to 100 weight-% or from 80 to 100 weight-% or from 90 to 100 weight-% of F0 may consist of bio-oil.

Preferably from 95 to 100 weight-%, more preferably from 98 to 100 weight-%, more preferably from 99 to 100 weight-%, of F0 consist of bio-oil. It is possible that from 99.5 to 100 weight-% or from 99.8 to 100 weight-% or from 99.9 weight-% of F0 consist of bio-oil.

Preferably, the bio-oil according to (I) has a total acid number (TAN) in the range of from 0 to 200 mg (KOH) per gram of F0 (mg(KOH)Zg(FO)), e.g., of from 50 to 200 mg(KOH)/g(FO) or from 100 to 200 mg(KOH)/g(FO), of from 0 to 150 mg(KOH)/g(FO), e.g., of from 50 to 150 mg(KOH)/g(FO) or from 100 to 150 mg(KOH)/g(FO), of from 0 to 100 mg (KOH)Zg(FO), e.g., of from 50 to 100 mg(KOH)/g(FO) or of from 70 to 100 mg(KOH)/g(FO), preferably of from 0 to 70 mg(KOH)/g(FO), e.g., of more than 60 mg(KOH)/g(FO) and not more than 70 mg(KOH)/g(FO), preferably of from 0.5 to 60 mg KOHZg(FO), more preferably 1 to 40 mg KOHZg(FO), preferably in the range of from 3 to 20 mg KOHZg(FO), determined as described in Reference Example 3.

In the context of the present invention, the bio-oil to be purified can have any oxygen content.

Preferably, the bio-oil according to (I) has an oxygen content in the range of from 0.5 to 70 g(O)/100 g(F0), e.g., of from more than 25 to not more than 70 g(O)/100 g(F0), preferably of from 0.5 to 50 g(O)/100 g(F0), e.g., of from more than 15 to not more than 50 g(O)/100 g(F0), preferably of from 25 to 50 g(O)/100 g(F0), or of from 0.5 to 15 g(O)/100 g(F0), more preferably in the range of from 0.5 to 10 g(O)/100 g(F0), more preferably in the range of from 0.5 to 5 g(O)/100 g(F0), more preferably in the range of from 0.5 to 2 g(O)/100 g(F0), determined as described in Reference Example 4.

Preferably, the bio-oil according to (I) has a total chlorine content in the range of from 30 to 3,000 wppm (ppm by weight), more preferably from 30 to 500 wppm, more preferably from 30 to 300 wppm, determined as described in Reference Example 1.1.

Preferably, the bio-oil according to (I) has a chloride content of at most 40 wppm, more preferably in the range of from 0 to 30 wppm, determined as described in Reference Example 1.2.

Preferably, the bio-oil according to (I) has a nitrogen content in the range of from 50 to 20,000 wppm (ppm by weight), more preferably from 50 to 5,000 wppm, more preferably from 100 to 4,000 wppm, determined as described in Reference Example 2. Preferably, the bio-oil according to (i) has a sulfur content of not more than 5,000 wppm (ppm by weight), preferably not more than 3,000 wppm, more preferably not more than 800 wppm, determined as described in Reference Example 5.

The bio-oil of (i) is obtainable or obtained from biomass by performing mechanical and physical operations as well as chemical processes. Bio-oils are liquid compound mixtures, mainly comprising highly oxygenated compounds (e.g., glycerides, esters, carboxylic acids, phenols, alcohols, ketones, aldehydes, furans, and sugars) and water, while its exact composition depends on the biomass feedstocks and the processing steps applied. The term bio-oil includes in particular vegetable oils like rapeseed oil, sunflower oil, soybean oil, corn oil, castor oil, jatropha oil, palm oil, and macauba palm (kernel or pulp) oil, and processing residues thereof (like palm fatty acid distillate), waste cooking oil, tall oil, animal fats, and oils obtained by thermochemical conversion of biomass, e.g. biomass-derived pyrolysis or hydrothermal liquefaction oils, as well as mixtures thereof. Vegetable oils are mainly composed of glycerides, in particular of triglycerides, i.e. esters formed from glycerol and fatty acids.

The term biomass comprises any material of vegetable or animal origin, such as plants or parts thereof like crops, wood, or residues thereof, marine organisms like algae, and bio-waste such as organic food waste, e.g., meat industry waste, fish processing waste, or waste cooking oil.

Said mechanical and physical operations may include harvesting and collecting as well as crushing, cracking, cutting, shredding, grinding, chipping, milling, extrusion, irradiation, squeezing, pressing, filtering, sieving, adsorption, and thermal treatments such as drying and torrefaction.

Said chemical processes may include extraction, distillation, thermochemical conversions like pyrolysis or hydrothermal liquefaction, hydrolysis, saponification, neutralization, ketonization, and hydrogenation.

Preferably, (i) comprises

(i.1) removing a bio-oil from a storage tank, a truck, or a tank wagon.

Preferably, (ii.2) comprises

(11.2.1) introducing water into UM1 comprised in ZE;

(11.2.2) bringing in contact, more preferably mixing, F0 with water into UM 1 , obtaining a mixture PM1 comprising water and the bio-oil;

(11.2.3) introducing B into UM1 and bringing in contact, more preferably mixing, B with the mixture PM1 obtained in (ii.2.2) into UM1, obtaining a mixture M1 comprising an aqueous phase PA(1) and an organic phase Po(1 ), the pH of the aqueous phase PA(1 ) of M 1 being in the range of from 7.5 to 11 , more preferably in the range of from 8 to 10.

Preferably, (ii.2) comprises

(11.2.1) introducing water into UM1 comprised in Z_E;

(11.2.2) bringing in contact, more preferably mixing, F0 with water into ZE, obtaining a mixture PM1 comprising water and the bio-oil, wherein the aqueous phase of PM1 has a pH value pH(PM 1), more preferably measured by a pH-sensor in UM1; (ii.2.3) adjusting the pH of the aqueous phase of PM1 by introducing B into UM1 by bringing in contact, more preferably mixing, B with M1 obtained in (ii.2.2) into UM1, obtaining a mixture M1 comprising an aqueous phase PA(1) and an organic phase Po(1 ), the pH of the aqueous phase P_A(1) of M1 > pH(PM 1 ), the pH of PA(1) being in the range of from 7.5 to 11, more preferably in the range of from 8 to 10.

Alternatively, preferably (ii.2) comprises

(ii.2.1') mixing water and B, obtaining a mixture MO of water and B having a pH(MO) in the range of from 12 to 14;

(ii.2.2') introducing MO obtained according to (ii.2.1') into UM1 and bringing in contact, more preferably mixing, F0 with MO, obtaining a mixture M1 comprising an aqueous phase P_A(1) and an organic phase P_o(1 ), the pH of the aqueous phase P_A(1) of M1 being in the range of from 7.5 to 11, more preferably in the range of from 8 to 10.

In the context of the present invention, preferably, the extraction unit UM1 is one or more of a stirred vessel, a mixing pump and a static mixer, more preferably a stirred vessel.

In the context of the present invention, the skilled person depending on the nature/type of the bio-oil will know which temperature to apply in order to bring in contact the stream F0, water and the base B in the liquid phase according to its general knowledge.

Preferably, bringing in contact, preferably mixing, according to (ii.2) is performed at a temperature T 1 in the range of from 10 to 95 °C, more preferably in the range of from 15 to 85 °C, more preferably in the range of from 20 to 80 °C, more preferably in the range of from 20 to 50°C.

Preferably, bringing in contact, more preferably mixing, according to (ii.2) is performed at a pressure p1 in the range of from 0.8 to 1.2 bar(abs), more preferably in the range of from 0.9 to 1.1 bar(abs). More preferably, when T1 < 95 °C, bringing in contact, more preferably mixing, according to (ii.2) is performed at a pressure p1 in the range of from 0.8 to 1.2 bar(abs), more preferably in the range of from 0.9 to 1.1 bar(abs), more preferably at about 1 bar(abs).

In the context of the present invention, when T1 > 95 °C, the pressure p1 is in the range of from 1 to 16 bar(abs).

Preferably, the base B is one or more of an alkali metal compound, an alkaline earth metal compound (e.g., alkaline earth metal oxide and/or hydroxide such as calcium hydroxide) and ammonia. More preferably B is an alkali metal compound being one or more of potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate and sodium bicarbonate, more preferably one or more of potassium hydroxide, sodium hydroxide, potassium carbonate and sodium carbonate, more preferably one or more of potassium hydroxide and sodium hydroxide, more preferably potassium hydroxide or sodium hydroxide.

Preferably, water used in (ii) is demineralized water.

Preferably, according to (ii.2), the weight ratio of water to F0 is in the range of from 0.05:1 to 2:1, more preferably in the range of from 0.1 :1 to 1.5:1, more preferably in the range of from 0.1:1 to 1.2:1, more preferably in the range of from 0.1:1 to 0.5:1. Preferably, the liquid-liquid separation unit US1 is one or more of a hydrocyclone, a settler tank and a centrifuge, more preferably a decanter, a hydrocyclone, a settler tank or a centrifuge, more preferably a settler tank.

In the context of the present invention, UM1 and US1 are two distinct units.

Preferably, the separation in US1 according to (ii.3) is performed at a temperature in the range of from 10 to 95 °C, more preferably in the range of from 15 to 85 °C, more preferably in the range of from 20 to 80 °C, more preferably in the range of from 20 to 50°C.

Preferably, prior to passing M1 into US1 according to (ii.3), the process further comprises passing M1 into a solid-liquid separation unit SLS1 for removing solids, if any, in M1.

Preferably, the solid-liquid separation unit SLS1 is one or more of a filter and a centrifuge.

The solid-liquid-separation can be performed with a filter using a differential pressure as driving force or with a centrifuge working with centrifugal force to separate liquid and solids.

Using a filter means often a discontinuous solid-liquid-separation, where the pressure difference is increasing with increasing filtration time. After a certain amount of pressure difference or filtration time, the solids have to be removed from the filter via a backflush by a fluid or gas or a mixture of both (e.g., disposal filter, backflush filter) or by an automatic system (e.g., automatic cleaning filter) or rotating or vibrating (e.g., pressure leaf filter, candle filter, filter press). During the removal of the solids, a second parallel filter is started operation until a certain pressure difference or filtration time is reached, where the solid emptied filter will be in operation again.

The filtration can be performed with disposal filter (e.g., bag filter, filter with filter sheets or membranes), where the solids are removed by back flushing or the solids remain on the filter cloth, which lead to a substitution of the filter after a certain pressure difference or operational time.

The filtration can be supported by the use of a filter aid to improve the filtration behavior. That can lead to a potential usage of a continuous filter (e.g., belt filter, drum filter).

Centrifuges can be used for a discontinuous solid-liquid-separation or continuous solid-liquid-separation depending on the centrifuge type. Centrifuges (e.g., decanter centrifuge, separator centrifuge) can be used in a 2 phase (solid-liquid) or 3 phase-system of two liquid phases and solids to separate the solids from the liquid or liquids and the liquid from the liquid. In a separator centrifuge the solids have to be released after the centrifuge loaded to a maximum of solids (discontinuous) compared to a decanter centrifuge, where the solids are continuously separated and removed. The centrifugation can be supported by the use of flocculants to improve the centrifugation behavior.

Alternatively, preferably, between UM1 and US1, no separation unit is located. In this regard, M1 removed from UM1 is passed directly into US1.

It is conceivable that the units UM1 and US1 be juxtaposed for example forming a mixer-settler.

Preferably, the process further comprises passing the stream FA(1 ) comprising PA(1 ) obtained according to (ii.3) in a separation unit USA1, preferably a settler tank, obtaining an aqueous stream SA1 comprising water. Preferably, the process further comprises one or more purification treatment step for purifying SA1 .

Preferably, the process further comprises recycling SA1 , more preferably purified SA1 (water), in UM1.

Preferably from 80 to 100 weight-%, more preferably from 85 to 100 weight-%, of FA(1 ) consists of water.

Alternatively, preferably, the process further comprises recycling at least a portion of water comprised in F_A(1) obtained according to (ii.3) into UM1.

In the context of the present invention, preferably, no organic solvent is used in (ii).

It is conceivable that the process further comprises, after (ii) and prior to (iii), an acidic treatment. In particular, the acidic treatment may comprise adding one or more acidic component to F1 .

It is conceivable that (ii) of the process of the present invention further comprises one or more subsequent extraction in Z_E.

Preferably, the process further comprises, when crud is formed at the interphase of P_A(1 ) and P_o(1) in US1, purging said crud from US1.

Preferably, US1 comprises a means for purging the optional crud formed at the interphase of P_A(1) and Po(1 ).

Preferably, the purged crud is subjected to one or more purification treatments. For example, the crud can be treated with a filter and/or a centrifuge.

As to (iii), according to a first alternative, (iii) preferably comprises

(iii.1) introducing F1 into a washing unit UM2 comprised in Zw;

(111.2) bringing in contact F1 with water in UM2 at a temperature T2 in the range of from 10 to 95 °C, obtaining a mixture M2 comprising an aqueous phase P_A(2) and an organic phase P_o(2), the pH of the aqueous phase P_A(2) of M2 being in the range of from 7.5 to 11 , pH of P_A(2) < pH of P_A(1);

(111.3) passing the mixture M2 obtained according to (iii.2) into a liquid-liquid separation unit US2 comprised in Zw, US2 being located downstream of UM2, obtaining a stream F_A(2) comprising P_A(2) and a stream F2 comprising Po(2) being the purified bio-oil.

Preferably, the present invention relates to a process for purifying a bio-oil, the process comprising:

(i) providing a stream F0 comprising a bio-oil;

(11.1) introducing F0 into an extraction unit UM1 comprised in Z_E;

(11.2) bringing in contact F0 with water and a base B in UM1 at a temperature T1 in the range of from 10 to 200 °C, obtaining a mixture M1 comprising an aqueous phase P_A(1 ) and an organic phase Po(1 ), the pH of the aqueous phase P_A(1 ) of M1 being in the range of from 7.5 to 11; (11.3) passing the mixture M1 obtained according to (ii.2) into a liquid-liquid separation unit US1 comprised in ZE, US1 being located downstream of UM 1 , obtaining a stream FA(1 ) comprising PA(1) and a stream F1 comprising Po(1) being the extracted bio-oil;

(11.4) removing F1 from ZE;

(ill) subjecting the stream F1 provided in (ii) to washing in at least one washing zone Zw, Zw being located downstream of Z_E, obtaining a stream F2 comprising the purified bio-oil, wherein (ill) comprises (ill.1 ) introducing F1 into a washing unit UM2 comprised in Z_w;

(111.2) bringing in contact F1 with water in UM2 at a temperature T2 in the range of from 10 to 95 °C, obtaining a mixture M2 comprising an aqueous phase PA(2) and an organic phase Po(2), the pH of the aqueous phase PA(2) of M2 being in the range of from 7.5 to 11, pH of PA(2) < pH of PA(1);

(111.3) passing the mixture M2 obtained according to (ill.2) into a liquid-liquid separation unit US2 comprised in Zw, US2 being located downstream of UM2, obtaining a stream FA(2) comprising PA(2) and a stream F2 comprising Po(2) being the purified bio-oil; and optionally

(v) introducing F2 comprising the bio-oil obtained according to (ill) into at least one storage unit SU and storing said bio-oil in SU.

Such alternative is illustrated by Figures 1, 2, and 4.

Preferably, the washing unit UM2 is one or more of a stirred vessel, a mixing pump and a static mixer, more preferably a stirred vessel.

Preferably, according to (ill.2), the weight ratio of water to F1 is in the range of from 0.05:1 to 2:1, more preferably in the range of from 0.1 :1 to 1.5:1, more preferably in the range of from 0.1:1 to 1.2:1, more preferably in the range of from 0.1:1 to 0.5:1.

Preferably, when B is KOH or NaOH, the weight ratio of water to F1 is in the range of from 0.05:1 to 2:1, more preferably in the range of from 0.1 :1 to 1.5:1, more preferably in the range of from 0.1 :1 to 1.2:1, more preferably in the range of from 0.1 :1 to 0.5:1.

Preferably, T2 is in the range of from 15 to 85 °C, more preferably in the range of from 20 to 80 °C, more preferably in the range of from 20 to 50°C.

Preferably 0.75 T1 < T2 < 1 .25 T1 , more preferably 0.90 T1 < T2 < 1.1 T1.

Preferably, water used in (ill) is demineralized water.

Preferably, the liquid-liquid separation unit US2 is one or more of a hydrocyclone, a settler tank, and a centrifuge, more preferably a hydrocyclone, a settler tank or a centrifuge, more preferably a settler tank or centrifuge.

Preferably, UM2 and US2 are two distinct units. Preferably, the separation in US2 according to (iii.3) is performed at a temperature in the range of from 10 to 85 °C, more preferably in the range of from 15 to 85 °C, more preferably in the range of from 20 to 80 °C, more preferably in the range of from 20 to 50°C.

Optionally, prior to passing M2 into US2 according to (iii.3), the process further comprises passing M2 into a solid-liquid separation unit SLS2 for removing solids, if any, in M2.

Preferably, the solid-liquid separation unit SLS2 is one or more of a filter and a centrifuge.

Alternatively, preferably, between UM2 and US2, no separation unit is located. In this regard, M2 removed from UM2 is passed directly into US2.

It is conceivable that the units UM2 and US2 be juxtaposed for example forming a mixer-settler.

Preferably, the process further comprises, when crud is formed at the interphase of P_A(2) and P_o(2) in US2, purging said crud from US2.

As to (iii), according to a second alternative, (iii) preferably comprises (iii.T) introducing F1 into an extraction column UM+US comprised in Zw; (iii.2’) introducing water into UM+US;

(iii.3’) bringing in contact F1 with water in UM+US at a temperature T2' in the range of from 10 to 95 °C, obtaining a stream FA(2) comprising an aqueous phase PA(2), the pH of the aqueous phase P_A(2) of M2 being in the range of from 7.5 to 11 , pH of PA(2) < pH of PA(1), and obtaining a stream F2 comprising the purified bio-oil.

Such alternative is illustrated by Figure 3.

(I) providing a stream F0 comprising a bio-oil;

(11.1) introducing F0 into an extraction unit UM1 comprised in ZE;

(11.4) removing F1 from ZE;

(ill) subjecting the stream F1 provided in (ii) to washing in at least one washing zone Zw, Zw being located downstream of ZE, obtaining a stream F2 comprising the purified bio-oil, wherein (ill) comprises

(ill.1') introducing F1 into an extraction column UM+US comprised in Zw;

(iii.2') introducing water into UM+US;

(iii.3') bringing in contact F1 with water in UM+US at a temperature T2' in the range of from 10 to 95 °C, obtaining a stream F_A(2) comprising an aqueous phase P_A(2), the pH of the aqueous phase P_A(2) of M2 being in the range of from 7.5 to 11 , pH of P_A(2) < pH of P_A(1), and obtaining a stream F2 comprising the purified biooil; and optionally

Preferably, according to (iii.3'), the weight ratio of water to F1 is in the range of from 0.05: 1 to 2:1 , more preferably in the range of from 0.1 :1 to 1.5:1 , more preferably in the range of from 0.1 : 1 to 1.2: 1 , more preferably in the range of from 0.1 : 1 to 0.5:1.

Preferably, T2' is in the range of from 15 to 85 °C, more preferably in the range of from 20 to 80 °C, more preferably in the range of from 20 to 50°C.

Preferably 0.75 T1 < T2’ < 1.25 T1 , more preferably 0.90 T1 < T2’ < 1.1 T1. Preferably, (ill) is performed at a pressure p2 in the range of from 0.75 to 1.25 bar(abs), more preferably in the range of from 0.9 to 1.1 bar(abs), more preferably at about 1 bar(abs).

Preferably from 90 to 100 weight-%, more preferably from 95 to 100 weight-%, of F_A(2) consists of water.

In the context of the present invention, it is preferred that the process further comprising recycling at least a portion of water comprised in F_A(2) obtained according to (iii.3) in (ii.2) and/or (iii.2); or recycling at least a portion of water comprised in F_A(2) obtained according to (iii.3') in (ii.2) and/or (iii.2').

Preferably, recycling at least a portion of water comprised in F_A(2) obtained according to (iii.3) in (ii.2) and/or (iii.2) comprises passing the at least portion of water comprised in F_A(2) obtained according to (iii.3) into UM1 and/or UM2.

Preferably, recycling at least a portion of water comprised in F_A(2) obtained according to (iii.3') in (ii.2) and/or (iii.2') comprises passing the at least portion of water comprised in F_A(2) obtained according to (iii.3') into UM1 and/or UM+US. Preferably, water used in (iii) is demineralized water.

Preferably, no organic solvent is used in (iii).

Preferably, no base is added in (iii), the base being one or more of an alkali metal compound (such as potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate and sodium bicarbonate more preferably one or more of potassium hydroxide, sodium hydroxide, potassium carbonate and sodium carbonate), an alkaline earth metal compound and ammonia.

Preferably, the stream F2 comprising the purified bio-oil obtained according to (iii) has a total acid number (TAN) which is lower than the TAN of the bio-oil provided in (i).

Preferably, the stream F2 comprising the purified bio-oil obtained according to (iii) has a TAN in the range of from 0 to 40 mg KOH/g(F2), preferably of from 0 to 20 mg KOH/g(F2), more preferably in the range of from 0 to 10 mg KOH/g(F2), more preferably in the range of from 0 to 4 mg KOH/g(F2), determined as described in Reference Example 3.

Preferably, the stream F2 comprising the purified bio-oil obtained according to (iii) has an oxygen content equal to or lower than, more preferably lower than, the oxygen content of the bio-oil provided in (i).

Preferably, the stream F2 comprising the purified bio-oil has an oxygen content in the range of from 0 to 20 g(O)/100 g(F2), preferably of from 0 to 10 g(O)/100 g(F2), more preferably of from 0 to 5 g(O)/100 g(F2), most preferably of from 0 to 2 g(O)/100 g(F2), determined as described in Reference Example 4.

It is conceivable according to the present invention that the stream F2 comprising the purified bio-oil obtained according to (iii) has a reduced total chlorine content and/or chloride content compared to the bio-oil provided in (i). For example, the reduction of the total chlorine content and/or chloride content in F2 compared to the bio-oil provided in (i) can be in the range of from 1 to 100%, or in the range of from 1 to 80% or in the range of from 10 to 50%.

It is conceivable according to the present invention that the stream F2 comprising the purified bio-oil obtained according to (iii) has a nitrogen content lower than the nitrogen content of the bio-oil provided in (i). It is conceivable according to the present invention that the stream F2 comprising the purified bio-oil obtained according to (iii) has a sulfur content lower than the sulfur content of the bio-oil provided in (i).

Optionally, the process of the present invention further comprises one or more subsequent washing in Zw. According to this option, the process further comprises

(iv) subjecting at least a portion of the stream F2 obtained according to (iii) to one or more subsequent washing in Zw, wherein (iv) comprises:

(iv.1 ) optionally introducing at least a portion of F2, preferably F2, obtained according to (iii) into a washing unit UM3 comprised in Zw, UM3 being located downstream of US2; bringing in contact the at least portion of F2, preferably F2, with water in UM3 at a temperature T3 in the range of from 10 to 95 °C, obtaining a mixture M3 comprising an aqueous phase PA(3) and an organic phase Po(3) of M3 being in the range of from 7.5 to 11, pH of PA(3) < pH of PA(1 ); passing the mixture M3 in a liquid-liquid separation unit US3 comprised in Zw, US3 being located downstream of UM3, obtaining a stream FA(3) comprising PA(3) and a stream F3 comprising Po(3) being the purified bio-oil;

(iv.2) introducing at least a portion of F2, preferably F2, obtained according to (iii), or at least a portion of F3, preferably F3, obtained according to (iv.1), into a washing unit UM4 comprised in Zw, UM4 being located downstream of US3;

(iv.3) bringing in contact the at least portion of F2, preferably F2, or the at least portion of F3, preferably F3, with water in UM4 at a temperature T4 in the range of from 10 to 95 °C, obtaining a mixture M4 comprising an aqueous phase PA(4) and an organic phase Po(4), the pH of the aqueous phase PA(4) of M4 being in the range of from 7.5 to 11 , pH of PA(4) < pH of P_A(1 );

(iv.4) passing the mixture M4 obtained according to (iv.3) in a liquid-liquid separation unit US4 comprised in Zw, US4 being located downstream of UM4, obtaining a stream F_A(4) comprising P_A(4) and a stream F4 comprising P_o(4) being the purified bio-oil.

Said option is illustrated for example by Figure 4.

Preferably, pH of P_A(3) < pH of P_A(2).

Preferably, pH of P_A(4) < pH of P_A(2).

Preferably, pH of P_A(4) < pH of P_A(3). More preferably, pH of P_A(4) < pH of P_A(3) < pH of P_A(2) < pH of P_A(1).

Preferably, according to said option, the process further comprises recycling at least a portion of F_A(4) into UM2 and/or UM3 (if present).

Preferably from 90 to 100 weight-%, more preferably from 95 to 100 weight-%, of FA(4) consists of water. Preferably, UM4, if present, is one or more of a stirred vessel, a mixing pump and a static mixer, more preferably a stirred vessel.

Preferably, according to (iv.3), the weight ratio of water to the at least portion of F2, more preferably F2, or the at least portion of F3, more preferably F3, is in the range of from 0.05:1 to 2:1, more preferably in the range of from 0.1 :1 to 1.5:1, more preferably in the range of from 0.1 :1 to 1.2:1, more preferably in the range of from 0.1 :1 to 0.5:1.

Preferably, T4 is in the range of from 15 to 85 °C, more preferably in the range of from 20 to 80 °C, more preferably in the range of from 20 to 50 °C.

Preferably 0.75 T1 < T4 < 1 .25 T1 , more preferably 0.90 T1 < T4 < 1 .1 T1.

Preferably, the liquid-liquid separation unit US4 is one or more of a hydrocyclone, a settler tank, and a centrifuge, more preferably a hydrocyclone, a settler tank or a centrifuge, more preferably a settler tank or centrifuge.

Preferably, UM4 and US4 are two distinct units.

Preferably, the separation in US4 according to (iv.4) is performed at a temperature in the range of from 10 to 85 °C, more preferably in the range of from 15 to 85 °C, more preferably in the range of from 20 to 80 °C, more preferably in the range of from 20 to 50 °C.

Preferably, prior to passing M4 in US4 according to (iv.4), the process further comprises passing M4 in a solid-liquid separation unit SLS4 for removing solids, if any, in M4.

Preferably, the solid-liquid separation unit SLS4 is one or more of a filter and a centrifuge.

The solid-liquid-separation can be performed with a filter using a differential pressure as driving force or with a centrifuge working with centrifugal force to separate liquid and solids. Using a filter means often a discontinuous solid-liquid-sepa- ration, where the pressure difference is increasing with increasing filtration time. After a certain amount of pressure difference or filtration time, the solids have to be removed from the filter via a backflush by a fluid or gas or a mixture of both (e.g., disposal filter, backflush filter) or by an automatic system (e.g., automatic cleaning filter) or rotating or vibrating (e.g., pressure leaf filter, candle filter, filter press). During the removal of the solids, a second parallel filter is started operation until a certain pressure difference or filtration time is reached, where the solid emptied filter will be in operation again.

Alternatively, preferably, between UM4 and US4, no separation unit is located. In this regard, M4 removed from UM4 is passed directly into US4.

Preferably, when (iv.1 ) is performed, the process further comprises recycling at least a portion of FA(3) into UM2.

Preferably from 90 to 100 weight-%, more preferably from 95 to 100 weight-%, of FA(3) consists of water.

Preferably, UM3, if present, is one or more of a stirred vessel, a mixing pump and a static mixer, more preferably a stirred vessel.

Preferably, according to (iv.1), the weight ratio of water to the at least portion of F2, more preferably F2, is in the range of from 0.05:1 to 2:1, more preferably in the range of from 0.1:1 to 1.5:1, more preferably in the range of from 0.1 :1 to 1.2:1, more preferably in the range of from 0.1 :1 to 0.5:1.

Preferably, T3 is in the range of from 15 to 85 °C, more preferably in the range of from 20 to 80 °C, more preferably in the range of from 20 to 50°C.

Preferably 0.75 T1 < T3 < 1 .25 T1 , more preferably 0.90 T1 < T3 < 1 .1 T1.

Preferably, the liquid-liquid separation unit US3 is one or more of a hydrocyclone, a settler tank and a centrifuge, more preferably a hydrocyclone, a settler tank or a centrifuge, more preferably a settler tank or centrifuge.

Preferably, UM3 and US3 are two distinct units.

Preferably, the separation in US3 according to (iv.1) is performed at a temperature in the range of from 10 to 85 °C, more preferably in the range of from 15 to 85 °C, more preferably in the range of from 20 to 80 °C, more preferably in the range of from 20 to 50°C.

Preferably, prior to passing M3 in US3 according to (iv.1 ), the process further comprises passing M3 in a solid-liquid separation unit SLS3 for removing solids, if any, in M3.

Preferably, the solid-liquid separation unit SLS3 is one or more of a filter and a centrifuge.

Alternatively, preferably, between UM3 and US3, no separation unit is located. In this regard, M3 removed from UM3 is passed directly into US3.

Preferably, water used in (iv) is demineralized water. Preferably, no organic solvent is used in (iv).

Preferably, no base is added in (iv), the base being one or more of an alkali metal compound (such as potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate and sodium bicarbonate more preferably one or more of potassium hydroxide, sodium hydroxide, potassium carbonate and sodium carbonate), an alkaline earth metal compound and ammonia.

Preferably, (iv) is performed at a pressure p3 in the range of from 0.75 to 1.25 bar(abs), more preferably in the range of from 0.9 to 1.1 bar(abs), more preferably at about 1 bar(abs).

In the context of the present invention, the process further comprises

(v) introducing F2 comprising the bio-oil obtained according to (iii), optionally F4 obtained according to (iv), into at least one storage unit SU and storing said bio-oil in SU.

Preferably, the storage unit SU is a storage tank, more preferably a storage tank made of one or more of steel and stainless steel, more preferably carbon steel and stainless steel.

Preferably, the process of the present invention further comprises one or more of a dechlorination step, a hydrogenation step, a hydroprocessing step, a steam cracking step, a hydrocracking step, a fluid catalytic cracking step, an adsorption step, a distillation step, a stripping step, and an aqueous extraction step.

Preferably, the process of the present invention is a continuous or semi-continuous process.

Preferably, the process of the present invention consists of (i), (ii), (iii) and optionally (iv) and optionally (v).

The present invention further relates to a unit for carrying out the process for purifying a bio-oil according to the present invention, the unit comprising at least one extraction zone ZE comprising an extraction unit UM1 and a liquid-liquid separation unit US1 , UM1 being located upstream of US1 ; an inlet means for introducing F0 into ZE; an outlet means for removing F1 from ZE; an inlet means for introducing F0 into UM1 ; an outlet means for removing M1 from UM1; an inlet means for introducing M1 into US1 ; an outlet means from removing F1 from US1; at least one washing zone Zw, located downstream of ZE, an inlet means for introducing F1 into Zw; an outlet means for removing F2 from Zw_; and optionally a storage tank.

Preferably, US1 comprises a means for purging the optional crud formed at the interphase of PA(1) and Po(1).

Preferably, according to the first alternative, Z_w comprises a washing unit UM2; a liquid-liquid separation unit US2, UM2 being located upstream of US2; an inlet means for introducing F1 into UM2; an inlet means for introducing water into UM2; an outlet means for removing M2 from UM2; an inlet means for introducing M2 into US2; an outlet means from removing F2 from US2.

Optionally, Z_w further comprises a washing unit UM4, preferably a mixing unit, and a liquid-liquid separation unit US4, UM4 being located downstream of US2 and US4 being located downstream of UM4.

Optionally Zw further comprises a washing unit UM3, preferably a mixing unit, and a liquid-liquid separation unit US3, UM3 being located downstream of US2 and upstream of UM4, US3 being located downstream of UM3 and upstream of UM4.

Preferably, according to the second alternative, Zw comprises an extraction column UM+US; an inlet means for introducing F1 into UM+US; an inlet means for introducing water into UM+US; an outlet means from removing F2 from UM+US.

In the context of the present invention, preferably, the unit further comprises one or more of a storage tank, a cracking zone, a dechlorination zone, a hydrogenation zone, a hydroprocessing zone, a stripping zone, and a distillation zone.

The present invention further relates to a purified bio-oil, obtainable or obtained by a process according to the present invention.

Preferably, the purified bio-oil of the present invention has a total acid number (TAN) in the range of from 0 to 40 mg (KOH) per gram of bio-oil (KOHZg(oil)), preferably of from 0 to 20 mg KOHZg(oil), more preferably in the range of from 0 to 10 mg KOHZg(oil), more preferably in the range of from 0 to 4 mg KOHZg(oil), more preferably in the range of from 0 to 1 mg KOHZg(oil), more preferably from 0 to less than 1 mg KOHZg(oil), determined as described in Reference Example 3. Preferably, the purified bio-oil of the present invention has an oxygen content in the range of from 0 to 20 g(O)/100 g(F2), preferably of from 0 to 10 g(O)/100 g(F2), more preferably of from 0 to 5 g(O)/100 g(F2), most preferably of from 0 to 2 g(O)/100 g(oil), determined as described in Reference Example 4.

The present invention is further illustrated by the following set of embodiments and combinations of embodiments resulting from the dependencies and back-references as indicated. In particular, it is noted that in each instance where a range of embodiments is mentioned, for example in the context of a term such as "The process of any one of embodiments 1 to 4", every embodiment in this range is meant to be explicitly disclosed for the skilled person, i.e. the wording of this term is to be understood by the skilled person as being synonymous to "The process of any one of embodiments 1, 2, 3 and 4". Further, it is explicitly noted that the following set of embodiments represents a suitably structured part of the general description directed to preferred aspects of the present invention, and, thus, suitably supports, but does not represent the claims of the present invention.

1. A process for purifying a bio-oil, the process comprising:

(i) providing a stream F0 comprising the bio-oil, wherein preferably the bio-oil is obtainable or obtained from biomass by performing mechanical and physical operations as well as chemical processes;

(11.1) introducing F0 into an extraction unit UM1 comprised in ZE;

(11.2) bringing in contact F0 with water and a base B in UM1 at a temperature T1 in the range of from 10 to 200 °C, obtaining a mixture M1 comprising an aqueous phase P_A(1) and an organic phase Po(1), the pH of the aqueous phase P_A(1) of M1 being in the range of from 7.5 to 11;

(11.3) passing the mixture M1 obtained according to (ii.2) into a liquid-liquid separation unit US1 comprised in Z_E, US1 being located downstream of UM1, obtaining a stream F_A(1) comprising P_A(1) and a stream F1 comprising P_o(1) being the extracted bio-oil;

(11.4) removing F1 from ZE;

(iii) subjecting the stream F1 provided in (ii) to washing in at least one washing zone Zw, Zw being located downstream of ZE, obtaining a stream F2 comprising the purified bio-oil; and optionally

2. The process of embodiment 1, wherein from 95 to 100 weight-%, preferably from 98 to 100 weight-%, more preferably from 99 to 100 weight-%, of F0 consist of bio-oil.

3. The process of embodiment 1 or 2, wherein the bio-oil according to (i) has an oxygen content in the range of from 0.5 to 70 g(O)/100 g(F0), e.g., of from more than 15 to not more than 50 g(O)/100 g(F0), or of from 0.5 to 15 g(O)/100g(F0), preferably in the range of from 0.5 to 10 g(O)/100g(F0), more preferably in the range of from 0.5 to 5 g(O)/100g(F0), more preferably in the range of from 0.5 to 2 g(O)/1 OOg(FO), determined as described in Reference Example 4.

4. The process of any one of embodiments 1 to 3, wherein the bio-oil according to (i) has a total acid number (TAN) in the range of from 0 to 200 mg (KOH)/g(FO), e.g., of from 50 to 200 mg(KOH)/g(FO) or of from 100 to

200 mg(KOH)/g(FO), preferably of from 0 to 100 mg (KOH)/g(F0), e.g., of from 50 to 100 mg(KOH)/g(FO) or of from 70 to 100 mg(KOH)/g(F0), preferably of from 0.5 to 60 mg KOH/g(F0), preferably 1 to 40 mg KOH/g(F0), preferably in the range of from 3 to 20 mg KOHZg(FO), determined as described in Reference Example 3.

5. The process of any one of embodiments 1 to 4, wherein the bio-oil according to (i) has a total chlorine content in the range of from 30 to 3,000 wppm (ppm by weight), preferably from 30 to 500 wppm, more preferably from 30 to 300 wppm, determined as described in Reference Example 1.1; wherein the bio-oil according to (i) has a chloride content of at most 40 wppm, more preferably in the range of from 0 to 30 wppm, determined as described in Reference Example 1.2.

6. The process of any one of embodiments 1 to 5, wherein the bio-oil according to (i) has a nitrogen content in the range of from 50 to 20,000 wppm (ppm by weight), preferably from 50 to 5,000 wppm, more preferably from 100 to 4,000 wppm, determined as described in Reference Example 2.

7. The process of any one of embodiments 1 to 6, wherein (ii.2) comprises

(11.2.1) introducing water into UM1 comprised in ZE;

(11.2.2) bringing in contact, preferably mixing, F0 with water into UM1 , obtaining a mixture PM1 comprising water and the bio-oil;

(11.2.3) introducing B into UM1 and bringing in contact, preferably mixing, B with the mixture PM1 obtained in (ii.2.2) into UM1 , obtaining a mixture M1 comprising an aqueous phase P_A(1) and an organic phase Po(1), the pH of the aqueous phase P_A(1) of M1 being in the range of from 7.5 to 11, preferably in the range of from 8 to 10; wherein preferably (ii.2) comprises

(11.2.1) introducing water into UM1 comprised in ZE;

(11.2.2) bringing in contact, preferably mixing, F0 with water into ZE, obtaining a mixture PM1 comprising water and the bio-oil, wherein the aqueous phase of PM1 having a pH value pH(PM 1), preferably measured by a pH-sensor in UM1 ;

(11.2.3) adjusting the pH of the aqueous phase of PM1 by introducing B into UM1 by bringing in contact, preferably mixing, B with M1 obtained in (ii.2.2) into UM1 , obtaining a mixture M1 comprising an aqueous phase P_A(1) and an organic phase Po(1 ), the pH of the aqueous phase P_A(1) of M1 > pH(PM1), the pH of P_A(1) being in the range of from 7.5 to 11, preferably in the range of from 8 to

10.

8. The process of any one of embodiments 1 to 6, wherein (ii.2) comprises

(ii.2. T) mixing water and B, obtaining a mixture MO of water and B having a pH(MO) in the range of from 12 to 14;

(ii.2.2') introducing MO obtained according to (ii.2.1') into UM1 and bringing in contact, more preferably mixing, F0 with MO, obtaining a mixture M1 comprising an aqueous phase P_A(1) and an organic phase Po(1), the pH of the aqueous phase P_A(1) of M1 being in the range of from 7.5 to 11, preferably in the range of from 8 to 10.

9. The process of any one of embodiments 1 to 8, wherein the extraction unit UM1 is one or more of a stirred vessel, a mixing pump and a static mixer, preferably a stirred vessel.

10. The process of any one of embodiments 1 to 9, wherein bringing in contact, preferably mixing, according to (ii.2) is performed at a temperature T 1 in the range of from 10 to 95 °C, preferably in the range of from 15 to 85 °C, more preferably in the range of from 20 to 80 °C, more preferably in the range of from 20 to 50°C.

11. The process of any one of embodiments 1 to 10, wherein the base B is one or more of an alkali metal compound, an alkaline earth metal compound and ammonia, preferably B is an alkali metal compound being one or more of potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate and sodium bicarbonate, more preferably one or more of potassium hydroxide, sodium hydroxide, potassium carbonate and sodium carbonate, more preferably one or more of potassium hydroxide and sodium hydroxide, more preferably potassium hydroxide or sodium hydroxide.

12. The process of any one of embodiments 1 to 11 , wherein water used in (ii) is demineralized water.

13. The process of any one of embodiments 1 to 12, wherein the liquid-liquid separation unit US1 is one or more of a hydrocyclone, a settler tank and a centrifuge, preferably a decanter, a hydrocyclone, a settler tank or a centrifuge, more preferably a settler tank.

14. The process of any one of embodiments 1 to 13, wherein the separation in US1 according to (ii.3) is performed at a temperature in the range of from 10 to 95 °C, preferably in the range of from 15 to 85 °C, more preferably in the range of from 20 to 80 °C, more preferably in the range of from 20 to 50°C.

15. The process of any one of embodiments 1 to 14, wherein, prior to passing M1 into US1 according to (ii.3), the process further comprises passing M1 into a solid-liquid separation unit SLS1 for removing solids, if any, in M1.

16. The process of embodiment 15, wherein the solid-liquid separation unit SLS1 is one or more of a filter and a centrifuge.

17. The process of any one of embodiments 1 to 16, further comprising passing the stream F_A(1) comprising P_A(1) obtained according to (ii.3) in a separation unit USA1 , preferably a settler tank, obtaining an aqueous stream SA1 comprising water.

18. The process of any one of embodiments 1 to 17, wherein no organic solvent is used in (ii).

19. The process of any one of embodiments 1 to 18, further comprising, when crud is formed at the interphase of P_A(1) and Po(1) in US1 , purging said crud from US1.

20. The process of any one of embodiments 1 to 19, wherein (ill) comprises

(ill.1) introducing F1 into a washing unit UM2 comprised in Z_w;

(111.2) bringing in contact F1 with water in UM2 at a temperature T2 in the range of from 10 to 95 °C, obtaining a mixture M2 comprising an aqueous phase P_A(2) and an organic phase Po(2), the pH of the aqueous phase P_A(2) of M2 being in the range of from 7.5 to 11 , pH of P_A(2) < pH of P_A(1);

(111.3) passing the mixture M2 obtained according to (ill.2) into a liquid-liquid separation unit US2 comprised in Zw, US2 being located downstream of UM2, obtaining a stream F_A(2) comprising P_A(2) and a stream F2 comprising Po(2) being the purified bio-oil.

21 . The process of embodiment 20, wherein the washing unit UM2 is one or more of a stirred vessel, a mixing pump and a static mixer, more preferably a stirred vessel.

22. The process of embodiment 20 or 21 , wherein, according to (ill.2), the weight ratio of water to F1 is in the range of from 0.05: 1 to 2:1 , preferably in the range of from 0.1 : 1 to 1.5: 1, more preferably in the range of from 0.1 :1 to 1.2:1 , more preferably in the range of from 0.1 : 1 to 0.5:1 or more preferably in the range of from 0.8:1 to 1.2: 1.

23. The process of any one of embodiments 20 to 22, wherein the liquid-liquid separation unit US2 is one or more of a hydrocyclone, a settler tank, and a centrifuge, preferably a hydrocyclone, a settler tank or a centrifuge, more preferably a settler tank or centrifuge.

24. The process of any one of embodiments 20 to 23, wherein the separation in US2 according to (ill.3) is performed at a temperature in the range of from 10 to 85 °C, preferably in the range of from 15 to 85 °C, more preferably in the range of from 20 to 80 °C, more preferably in the range of from 20 to 50°C. The process of any one of embodiments 20 to 24, wherein, prior to passing M2 into US2 according to (iii.3), the process further comprises passing M2 into a solid-liquid separation unit SLS2 for removing solids, if any, in M2. The process of embodiment 25, wherein the solid-liquid separation unit SLS2 is one or more of a filter and a centrifuge. The process of any one of embodiments 20 to 24, wherein, between UM2 and US2, no separation unit is located. The process of any one of embodiments 1 to 19, wherein (ill) comprises

(iii. T) introducing F1 into an extraction column UM+US comprised in Zw;

(ill.2') introducing water into UM+US;

(iii.3') bringing in contact F1 with water in UM+US at a temperature T2' in the range of from 10 to 95 °C, obtaining a stream F_A(2) comprising an aqueous phase P_A(2), the pH of the aqueous phase P_A(2) of M2 being in the range of from 7.5 to 11 , pH of P_A(2) < pH of P_A(1), and obtaining a stream F2 comprising the purified biooil. The process of embodiment 28, wherein, according to (iii.3'), the weight ratio of water to F1 is in the range of from 0.05:1 to 2: 1, preferably in the range of from 0.1 :1 to 1.5:1 , more preferably in the range of from 0.1 :1 to 1.2: 1, more preferably in the range of from 0.1 : 1 to 0.5:1 or more preferably in the range of from 0.8:1 to 1.2:1. The process of any one of embodiments 20 to 29, further comprising recycling at least a portion of water comprised in F_A(2) obtained according to (iii.3) in (ii.2) and/or (ill.2); or recycling at least a portion of water comprised in F_A(2) obtained according to (iii.3') in (ii.2) and/or (ill.2'); and/or recycling at least a portion of water comprised in F_A(1) obtained according to (ii.3) in (ii.2). The process of any one of embodiments 1 to 30, wherein no organic solvent is used in (ill). The process of any one of embodiments 1 to 31 , wherein the stream F2 comprising the purified bio-oil obtained according to (ill) has a total acid number (TAN) which is lower than the TAN of the bio-oil provided in (I). The process of embodiment 32, wherein the stream F2 comprising the purified bio-oil obtained according to (ill) has a TAN in the range of from 0 to 40 mg KOH/g(F2), preferably of from 0 to 20 mg KOH/g(F2), more preferably in the range of from 0 to 10 mg KOH/g(F2), more preferably in the range of from 0 to 4 mg KOH/g(F2), determined as described in Reference Example 3. 34. The process of any one of embodiments 1 to 33, wherein the stream F2 comprising the purified bio-oil obtained according to (iii) has an oxygen content equal to or lower than, more preferably lower than, the oxygen content of the bio-oil provided in (I).

35. The process of embodiment 34, wherein the stream F2 comprising the purified bio-oil has an oxygen content in the range of from 0 to 20 g(O)/100 g(F2), preferably of from 0 to 10 g(O)/100 g(F2), more preferably of from 0 to 5 g(O)/100 g(F2), most preferably of from 0 to 2 g(0)/100g(F2), determined as described in Reference Example 4.

36. The process of any one of embodiments 1 to 35, as far as embodiment 36 depends on any one of embodiments 20 to 27, further comprising

(iv.1) optionally introducing at least a portion of F2, preferably F2, obtained according to (iii) into a washing unit UM3 comprised in Zw, UM3 being located downstream of US2; bringing in contact the at least portion of F2, preferably F2, with water in UM3 at a temperature T3 in the range of from 10 to 95 °C, obtaining a mixture M3 comprising an aqueous phase P_A(3) and an organic phase Po(3) of M3 being in the range of from 7.5 to 11, pH of PA(3) < pH of PA(1); passing the mixture M3 in a liquid-liquid separation unit US3 comprised in Zw, US3 being located downstream of UM3, obtaining a stream FA(3) comprising PA(3) and a stream F3 comprising Po(3) being the purified bio-oil;

(iv.3) bringing in contact the at least portion of F2, preferably F2, or the at least portion of F3, preferably F3, with water in UM4 at a temperature T4 in the range of from 10 to 95 °C, obtaining a mixture M4 comprising an aqueous phase PA(4) and an organic phase Po(4), the pH of the aqueous phase PA(4) of M4 being in the range of from 7.5 to 11, pH of PA(4) < pH of PA(1);

(iv.4) passing the mixture M4 obtained according to (iv.3) in a liquid-liquid separation unit US4 comprised in Zw, US4 being located downstream of UM4, obtaining a stream FA(4) comprising PA(4) and a stream F4 comprising Po(4) being the purified bio-oil.

37. The process of any one of embodiments 1 to 36, further comprising

38. The process of embodiment 37, wherein the storage unit SU is a storage tank, preferably a storage tank made of one or more of steel and stainless steel, more preferably carbon steel and stainless steel. 39. The process of any one of embodiments 1 to 38, further comprising one or more of a dechlorination step, a hydrogenation step, a hydroprocessing step, a steam cracking step, a hydrocracking step, a fluid catalytic cracking step, a distillation step, a stripping step, and an aqueous extraction step.

40. The process of any one of embodiments 1 to 39, being a continuous or semi-continuous process.

41 . A unit for carrying out the process for purifying a bio-oil according to any one of embodiments 1 to 40, the unit comprising at least one extraction zone ZE comprising an extraction unit UM1 and a liquid-liquid separation unit US1, UM1 being located upstream of US1; an inlet means for introducing F0 into ZE; an outlet means for removing F1 from ZE; an inlet means for introducing F0 into UM1; an outlet means for removing M1 from UM1; an inlet means for introducing M1 into US1; an outlet means from removing F1 from US1; at least one washing zone Zw, located downstream of ZE, an inlet means for introducing F1 into Zw; an outlet means for removing F2 from Zw; and optionally a storage tank.

42. The unit of embodiment 41, wherein US1 comprises a means for purging the optional crud formed at the interphase of P_A(1) and P_o(1).

43. The unit of embodiment 41 or 42, wherein Zw comprises a washing unit UM2; a liquid-liquid separation unit US2, UM2 being located upstream of US2; an inlet means for introducing F1 into UM2; an inlet means for introducing water into UM2; an outlet means for removing M2 from UM2; an inlet means for introducing M2 into US2; an outlet means from removing F2 from US2.

44. The unit of embodiment 43, wherein Zw further comprises a washing unit UM4, preferably a mixing unit, and a liquid-liquid separation unit US4, UM4 being located downstream of US2 and US4 being located downstream of UM4; wherein optionally Zw further comprises a washing unit UM3, preferably a mixing unit, and a liquid-liquid separation unit US3, UM3 being located downstream of US2 and upstream of UM4, US3 being located downstream of UM3 and upstream of UM4.

45. The unit of embodiment 41 or 42, wherein Zw comprises an extraction column UM+US; an inlet means for introducing F1 into UM+US; an inlet means for introducing water into UM+US; an outlet means from removing F2 from UM+US.

46. The unit of any one of embodiments 41 to 45, further comprising one or more of a storage tank, a cracking zone, an adsorption zone, a dechlorination zone, a hydrogenation zone, a hydroprocessing zone, a stripping zone and a distillation zone.

47. A purified bio-oil, obtainable or obtained by a process according to any one of embodiments 1 to 40.

In the context of the present invention, the term "crud” refers to an electrostatic-, solid- or surface active stabilized layer, containing aqueous and organic phases, that most commonly accumulates at the aqueous/organic interface in the settlers of solvent-extraction processes as well known in the art.

In the context of the present invention, a term "X is one or more of A, B and C”, wherein X is a given feature and each of A, B and C stands for specific realization of said feature, is to be understood as disclosing that X is either A, or B, or C, or A and B, or A and C, or B and C, or A and B and C. In this regard, it is noted that the skilled person is capable of transfer to above abstract term to a concrete example, e.g., where X is a chemical element and A, B and C are concrete elements such as Li, Na, and K, or X is a temperature and A, B and C are concrete temperatures such as 10 °C, 20 °C, and 30 °C. In this regard, it is further noted that the skilled person is capable of extending the above term to less specific realizations of said feature, e.g., "X is one or more of A and B” disclosing that X is either A, or B, or A and B, or to more specific realizations of said feature, e.g., "X is one or more of A, B, C and D”, disclosing that X is either A, or B, or C, or D, or A and B, or A and C, or A and D, or B and C, or B and D, or C and D, or A and B and C, or A and B and D, or B and C and D, or A and B and C and D.

The present invention is further illustrated by the following examples. Examples

Reference Example 1 .1 Measurement of total chlorine content (wppm)

The sample is filtered with a 0.45pm syringe filter before analysis. The chlorine content is determined by combustion of the respective sample at 1050°C. Resulting combustion gases, i.e., hydrogen chloride, are led into a cell in which coulometric titration is performed.

Reference Example 1 .2 Measurement of chloride content (wppm)

The sample is filtered with a 0.45pm syringe filter before analysis. The chloride content is determined by ion chromatography. Apparatus: Ion chromatograph 850 Professional (Metrohm) (Pre column: Metrosep A Supp4/5 S-Guard and Analytical column: Metrosep A Supp 5250/4; Flow: 0.7 mL/min; Column temperature: 30°C; Detector temperature: 40°C; Inject volume: 25 pL; Suppressor MSM HC Rotor A). As Eluant: 3.2 mmol/L Na2CO3 ; 1.0 mmol/L NaHCO3 and as Suppressor regenerant: 50 mmol/L sulfuric acid were used.

Sample preparation: 0.2 g - 0.4 g of the sample were weighed and dissolved in 10 mL toluene. For analyte extraction, 10 mL deionized water were added. After centrifugation, the aqueous phase was extracted and analyzed. Samples with a concentration below the limit value of the method were spiked with 20 pg/L chloride standard solution (corresponding to a limit value of 1 mg/kg chloride in the sample) to check the recovery rate.

Reference Example 2 Measurement of N content (wppm)

The nitrogen content is determined by combustion of the respective sample at 1000°C. NO contained in resulting combustion gases reacts with ozone so that NO2* is formed. Relaxation of excited nitrogen species is detected by chemiluminescence detectors according to ASTM D4629 (N). Calibration range is from 0.5 wppm to 50 wppm. Samples with higher concentrations are diluted with xylene to be in calibration range.

Reference Example 3 Determination of the total acid number (TAN)

The total acid number was determined by titration with KOH according to ASTM D3242.

Reference Example 4 Measurement of oxygen content (O-content) (weight- %)

The sample (1 - 10 mg) is pyrolyzed/reduced in a reductive gas atmosphere on a soot contact, the oxygen was converted hereby to carbon monoxide (CO). The carbon monoxide is detected and quantified via IR spectrometry. The analyzer used is elemental analyzer model rapid OXY cube®.

Reference Example 5: Measurement of sulfur content in a bio-oil (wppm)

The sulfur content in a given bio-oil is measured according to ASTM D5453.

Reference Example 6 Corrosion tests Two corrosion coupons of steel material 1 . 0425 (DIN EN 10028-2) are stored in the tested pyrolysis oil at 60°C and under nitrogen atmosphere. Every 7 days the samples are washed with water, xylene and water again, dried and weighed. The medium is exchanged with fresh pyrolysis oil and the samples are put back. After 4 cycles (28 days) the average linear corrosion rate* is calculated and the coupons were examined. The surfaces of the corrosion coupons are examined in accordance to DIN 50905 using a binocular microscope at 10-20x magnification to detect various corrosion phenomena, frequency, extent and distribution of localized corrosion as well as discoloration of the coupon surface, scale formation or corrosion products. The depth of localized corrosion, e.g., shallow pit corrosion, is measured by optical focusing with light microscopy.

Vi: average linear corrosion rate [mm/year] Dm: weight loss [g] F: surface of coupon [cm²] r: density of material [g/cm³] T: testing time [days]

The following Examples, Reference Example, and Comparative Example are based on experiments performed with an oil obtained by pyrolysis of solid waste material. The one of skill in the art will appreciate, however, that the conclusions drawn therefrom are equally applicable to the bio-oils described herein. For instance, it is known, e.g., from Eschen- bacher et al. (Energy Fuels 2021, 35, 18333-18369; as well as respective reference documents cited therein) that bio- mass-derived pyrolysis oils often exhibit high oxygen contents and high total acid numbers.

Example 1 Process for purifying a pyrolysis oil according to the present invention

A feed stream F0 comprising a pyrolysis oil having a total acid number (TAN) of about 8.5 mg KOH/g, a total chlorine content of 24 wppm, a chloride content < 5 wppm, a nitrogen content of 0.5 wt.-% based on the weight of the pyrolysis oil and an oxygen content of 1 wt.-% based on the weight of the pyrolysis oil, a density of 916 kg/m³ and a viscosity of 6.4 mPas was subjected to extraction (1.1) with NaOH or (1.2) and (1.3) with KOH at pH 10 at T = 30°C. To do so, F0 was introduced in a 1 .3 L agitated glass vessel. Demineralized water was then added into the vessel (phase ratio v (demineralized water/pyro oil) = 0.3 kg/kg) forming a mixture. The pH of the aqueous phase of the mixture was adjusted to 10 with 10 % NaOH (1.1) or KOH (1.2 and 1.3). The obtained mixture was mixed for 15 min. For the mixture with NaOH, the mixture was transferred to a centrifuge. For the mixtures with KOH, said mixtures were settled for 5 (1 .2) and 7 (1 .3) minutes in the glass vessel of 1 .3 L. The aqueous phase was thus separated after settling from the organic (oil) phase. The organic phase was analyzed.

After separation of the water phase of the neutralization step, demineralized water was further added to the organic phase for removing remaining salts /caustic (entrainment). Demineralized water was added with a phase ratio v (demineralized water/ organic phase) = 1 kg/kg. The obtained mixture water/organic (oil) phase was introduced into a settler (liquid/liquid separation unit). The aqueous phase was separated after settling from the organic phase, said washed organic phase was analyzed. Different settling durations were applied depending on the sample, for 1.1, it was 8 min; for 1.2 it was 6 min and for 1.3 it was 2.5 min. The results are listed in Table 1 below. Table 1 Pyrolysis oil composition before extraction, after extraction and after washing

*pH of the aqueous phase

**pH of the aqueous phase of FO after FO was simply washed with demineralized water not measured/determined. As may be taken from Table 1 , the extraction + washing permits to purify the pyrolysis oil by reducing its TAN, its oxygen content as well as the N- and Cl-contents.

Corrosion test: Corrosion tests were performed as described in Reference Example 6 with the pyrolysis oil FO and with the purified pyrolysis oil obtained after washing for samples 1.1, 1.2 and 1.3. The results are detailed in Tables 2 to 4 below.

Table 2 Corrosion test on 2 coupons of steel material 1. 0425 (DIN EN 10028-2) with pyrolysis oil F0

As may be taken from Table 2, the pyrolysis oil prior the purification treatment according to the present invention was corrosive. The local corrosion and pitting corrosion are not acceptable. Table 3 Corrosion test on 2 coupons of steel material 1. 0425 (DIN EN 10028-2) with purified pyrolysis oil (sample

1.1 after washing) with reduced TAN and O content

As may be taken from Table 3, the pyrolysis oil purified according to the present invention with NaOH reduces greatly the corrosion: reduction of the average linear corrosion vl of more than 99% and only sporadic rust spots (superficial). There is thus no pitting corrosion or local corrosion as opposed to the comparative example which demonstrates a clear improvement. Said purified pyrolysis oil does not affect the technical stability of the steel material (vl of less than 0.1 mm/y in combination with no pitting or localized corrosion). Table 4 Corrosion test on 2 coupons of steel material 1 .0425 (DIN EN 10028-2) with purified pyrolysis oil (sample

1 .2 after washing) with reduced TAN and 0 content

As may be taken from Table 4, the pyrolysis oil purified according to the present invention with KOH reduces greatly the corrosion: reduction of the average linear corrosion vl of about 80% and only sporadic rust spots (superficial). There is thus no pitting corrosion or local corrosion as opposed to the comparative example which demonstrates a clear improvement. Said purified pyrolysis oil does not affect the technical stability of the steel material.

Therefore, it has been demonstrated that the pyrolysis oil prior the purification treatment according to the present invention was corrosive while the purified pyrolysis oil (TAN < 1) permits to greatly reduce the corrosion and does not affect the technical stability of the steel material.

Reference Example 7 Process for purifying a pyrolysis oil not according to the present invention - Corrosion testing

In order to identify the optimum conditions of purification, a further process has been conducted for purifying a pyrolysis oil. A feed stream F0 comprising a pyrolysis oil as in Example 1 was subjected to extraction with KOH at pH 7 at T = 50°C. To do so, F0 was introduced in a 1 .3 L agitated glass vessel. Demineralized water was then added into the vessel (phase ratio v (water/ pyrolysis oil) = 0.5 kg/kg) forming a mixture. The pH of the aqueous phase of the mixture was adjusted to 7.2 with 25 wt.-% KOH. The obtained mixture was mixed for 15 min. The obtained aqueous phase was separated after settling (for 2 minutes) from the organic phase. The organic phase was analyzed.

Again, a washing step was done. Demineralized water was added to the organic phase with a phase ratio v (demineralized water/ organic phase) = 0.5 kg/kg to remove salts and caustic entrainment from the pyrolysis oil. The results are listed in Table 5 below. Table 5

*pH of the aqueous phase

**pH of the aqueous phase of FO after FO was simply washed with demineralized water.

As may be taken from Table 5, at pH 7 the reduction of the TAN was much less.

Corrosion test: Corrosion tests were performed as described in Reference Example 6 with the pyrolysis oil FO (cf. Table 2 above) and with the purified pyrolysis oil obtained not according to the present invention (different pH). The results are detailed in Table 6 below.

Table 6 Corrosion test on 2 coupons of steel material 1. 0425 (DIN EN 10028-2) with purified pyrolysis oil obtained not according to the present invention

As may be taken from Table 6, the pyrolysis oil purified not according to the present invention with KOH at pH 7 reduces the average linear corrosion vl. However, the pyrolysis oil is more corrosive than the purified pyrolysis oils obtained according to the process of the present invention (cf. Tables 3 and 4 above). Even if vl has been reduced, the presence of local corrosion and pitting corrosion is not acceptable.

Example 2 Process for purifying a pyrolysis oil according to the present invention

A feed stream FO comprising a pyrolysis oil having a total acid number (TAN) of 15.9 mg KOH/g, a density of 863 kg/m³ and a viscosity of 1 .7 mPas was subjected to extraction with NaOH at pH 10 at T = 25°C. To do so, FO was introduced in a 1 .3 L agitated glass vessel. Demineralized water was then added into the vessel (phase ratio v (demineralized wa- ter/pyro oil) = 0.5 kg/kg) forming a mixture. The pH of the aqueous phase of the mixture was adjusted to 10 with 25 % NaOH The obtained mixture was mixed for 15 min. For the mixture with NaOH, the mixture was transferred to a centrifuge. The aqueous phase was thus separated after settling from the organic (oil) phase. The organic phase was analyzed.

After separation of the water phase of the neutralization step, demineralized water was further added to the organic phase for removing remaining salts /caustic (entrainment). Demineralized water was added with a phase ratio v (demineralized water/ organic phase) = 1 kg/kg. The obtained mixture water/organic (oil) phase was introduced into a settler (liquid/liquid separation unit). The aqueous phase was separated after settling from the organic phase, said washed organic phase was analyzed. The results are listed in Table 7 below.

Table 7 Pyrolysis oil composition before extraction and after extraction

*pH of the aqueous phase

**pH of the aqueous phase of F0 after F0 was simply washed with demineralized water.

As may be taken from Table 7, the extraction (neutralization) permits to purify the pyrolysis oil by reducing its TAN.

Comparative Example 1 Process for purifying a pyrolysis oil not according to the present invention

A feed stream F0 comprising a pyrolysis oil having a total acid number (TAN) of 7 mg KOH/g was subjected to a first washing step with demineralized water into a 250 ml glass bottle with a phase ratio of v (demin. water I pyrolysis oil (F0)) = 1 kg/kg. The mixture was shaken. The pH of the aqueous phase of the mixture was of pH 4.3. The obtained mixture water I organic phase (oil) was introduced into a centrifuge. The aqueous phase was thus separated from the organic (oil) phase.

After separating of the water phase from the organic phase, demineralized water was further added to the organic phase for a second washing step. Demineralized water was added with a phase ratio v (demineralized water/ organic phase) = 1 kg/kg. The obtained mixture water/organic phase (oil) was introduced into a centrifuge. The aqueous phase was separated after from the organic phase. Finally, a third washing step was performed, and the aqueous phase was separated with a centrifuge from the organic phase, said washed organic phase was analyzed. The results are listed in Table 3 below. Table 8

*pH of the aqueous phase

As may be taken from Table 8, washing steps are not sufficient for reducing the TAN number.

Description of the figures

Figure 1 is a schematic representation of a unit for carrying out the process for purifying a bio-oil according to embodiments of the invention. The unit comprises an extraction zone ZE comprising an extraction unit UM1 and a liquidliquid separation unit US1, US1 being located downstream of UM1, and a washing zone Zw, downstream of ZE, comprising a washing unit UM2 and a liquid-liquid separation unit US2, US2 being located downstream of UM2. The stream FO comprising a bio-oil is introduced into UM1 together with water and a base B. FO, water and B are brought in contact in UM1 at a temperature in the range of from 10 to 200 °C, preferably in the range of from 10 to 95 °C. A mixture M1 is removed from UM1, said mixture comprising an aqueous phase P_A(1) and an organic phase P_o(1), the pH of the aqueous phase P_A(1) of M1 being in the range of from 7.5 to 11. M1 is introduced into US1. A stream F_A(1) comprising P_A(1) and a stream F1 comprising the extracted bio-oil (Po(1)) are obtained and removed from US1 and ZE. Further, F1 is introduced into UM2 together with water. F1 and water are brought in contact at a temperature in the range of from 10 to 95 °C. A mixture M2 is obtained, said mixture comprising an aqueous phase P_A(2) and an organic phase Po(2), the pH of the aqueous phase P_A(2) of M2 being in the range of from 7.5 to 11 , pH of P_A(2) < pH of P_A(1). M2 is then introduced into US2. A stream F2 comprising the purified bio-oil is obtained. A further stream F_A(2) comprising P_A(2) is also obtained. F2 can then be stored or transferred for further treatment(s). Optionally, F_A(1 ), aqueous stream, and/or F_A(2), aqueous stream, are recycled (not shown) in UM1 and/or UM2. Optionally, if crud is formed at the interphase of P_A(1) and P_o(1 ), said crud is removed from US1 with a purge (not shown).

Figure 2 is a schematic representation of a unit for carrying out the process for purifying a bio-oil according to embodiments of the invention. The unit comprises an extraction zone ZE comprising an extraction unit UM1, a solid-liquid separation unit SLS1 and a liquid-liquid separation unit US1, SLS1 being located downstream of UM1 and US1 being located downstream of SLS1, and a washing zone Zw, downstream of ZE, comprising a washing unit UM2, a solid-liquid separation unit SLS2 and a liquid-liquid separation unit US2, SLS2 being located downstream of UM2 and US2 being located downstream of SLS2. The process is as defined in Figure 1, except that M1 prior to be introduced into US1 is passed through SLS1 to remove solids if any and that M2 prior to be introduced into US2 is passed through SLS2 to remove solids if any. Figure 3 is a schematic representation of a unit for carrying out the process for purifying a bio-oil according to embodiments of the invention. The unit comprises an extraction zone ZE comprising an extraction unit UM1 and a liquidliquid separation unit US1 , US1 being located downstream of UM1, and a washing zone Zw, downstream of ZE, comprising a washing unit UM2 combined to a liquid-liquid separation unit US2. ZE optionally comprises a solid-liquid separation unit SLS1 , located downstream of UM1 and upstream of US1. The stream F0 comprising a bio-oil is introduced into UM1 together with water and a base B. F0, water and B are brought in contact in UM1 at a temperature in the range of from 10 to 200 °C, preferably in the range of from 10 to 95 °C. A mixture M1 is removed from UM1 , said mixture comprising an aqueous phase P_A(1) and an organic phase P_o(1 ), the pH of the aqueous phase P_A(1) of M1 being in the range of from 7.5 to 11. M1 is introduced into US1. If SLS1 is present, M1 is passed through SLS1 prior to be introduced into US1. A stream F_A(1) comprising P_A(1) and a stream F1 comprising the extracted bio-oil are obtained and removed from US1 and ZE. Further, F1 is introduced into the combined UM2/US2 being an extraction column. Water is also introduced into said column and brought in contact with F1 at a temperature in the range of from 10 to 95 °C, the phases of M2 are separated in the column, the pH of the aqueous phase P_A(2) of M2 being in the range of from 7.5 to 11 , pH of P_A(2) < pH of P_A(1). A stream F2 comprising the purified bio-oil is obtained (removed at the top of the column). A further stream F_A(2) comprising P_A(2) is also obtained (removed at the opposite of the column, namely the bottom). F2 can then be stored or transferred for further treatment(s). Optionally, F_A(2), aqueous stream, is recycled (not shown) in UM1 and/or Zw.

Figure 4 is a schematic representation of a unit for carrying out the process for purifying a bio-oil according to embodiments of the invention. The unit comprises an extraction zone ZE comprising an extraction unit UM1 , an optional solid-liquid separation unit SLS1 and a liquid-liquid separation unit US1, SLS1 being located downstream of UM1 and US1 being located downstream of SLS1 , and a washing zone Zw, downstream of ZE, comprising a washing unit UM2, an optional solid-liquid separation unit SLS2 and a liquid-liquid separation unit US2, SLS2 being located downstream of UM2 and US2 being located downstream of SLS2. The process is as defined in Figure 1 , except that M1 prior to be introduced into US1 is optionally passed through SLS1 to remove solids if any and that M2 prior to be introduced into US2 is optionally passed through SLS2 to remove solids if any. Z_w of the unit further comprises a washing unit UM4, an optional solid-liquid separation unit SLS4 and a liquid-liquid separation unit US4, SLS4 being located downstream of UM4 and US4 being located downstream of SLS4. F2 is introduced into UM4 together with water. F2 and water are brought in contact at a temperature in the range of from 10 to 95 °C. A mixture M4 is obtained, said mixture comprising an aqueous phase P_A(4) and an organic phase Po(4), the pH of the aqueous phase P_A(4) of M4 being in the range of from 7.5 to 11 , pH of P_A(4) < pH of P_A(1). M4 is then introduced into US4, and optionally passed through USL4 prior to be introduced into US4. A stream F4 comprising the purified bio-oil is obtained. A further stream F_A(4) comprising P_A(4) is also obtained. F4 can then be stored or transferred for further treatment(s). Optionally, F_A(4), aqueous stream, is recycled (not shown) in UM2.

Optionally, Z_w of the unit further comprises a washing unit UM3 and a liquid-liquid separation unit US3, it can further comprises a solid-liquid separation unit SL3, SLS3 if present being located downstream of UM3 and US3 being located downstream of SLS3. Hence, F2 is introduced into UM3 (not UM4) together with water. F2 and water are brought in contact at a temperature in the range of from 10 to 95 °C. A mixture M3 is obtained, said mixture comprising an aqueous phase PA(3) and an organic phase Po(3), the pH of the aqueous phase P_A(3) of M3 being in the range of from 7.5 to 11, pH of PA(3) < pH of PA(1). M3 is then introduced into US3, and optionally passed through USL3 prior to be introduced into US3. A stream F3 comprising the purified bio-oil is obtained. A further stream F_A(3) comprising P_A(3) is also obtained. F3 is then introduced into UM4 together with water. F3 and water are brought in contact at a temperature in the range of from 10 to 95 °C. A mixture M4 is obtained, said mixture comprising an aqueous phase P_A(4) and an organic phase P_o(4), the pH of the aqueous phase P_A(4) of M4 being in the range of from 7.5 to 11, pH of P_A(4) < pH of P_A(1). M4 is then introduced into US4, and optionally passed through USL4 prior to be introduced into US4. A stream F4 comprising the purified bio-oil is obtained. A further stream F_A(4) comprising P_A(4) is also obtained. F4 can then be stored or transferred for further treatment(s). Optionally, F_A(4), aqueous stream, is recycled (not shown) in UM2 and/or UM3. Optionally, F_A(3), aqueous stream, is recycled (not shown) in UM2. Optionally, F_A(2), aqueous stream, is recycled (not shown) in UM1.

Cited Literature - US 2021/0277324 A1

- WO 2014/165859 A1

- WO 2020/178599 A1

Claims

1. A process for purifying a bio-oil, the process comprising:

(i) providing a stream F0 comprising the bio-oil, wherein preferably the bio-oil is obtained from biomass by performing mechanical and physical operations as well as chemical processes;

(ii) subjecting the stream F0 provided in (I) to extraction in at least one extraction zone Z_E, obtaining a stream F1 comprising the extracted bio-oil, wherein (ii) comprises:

(11.1) introducing F0 into an extraction unit UM1 comprised in Z_E;

(11.2) bringing in contact F0 with water and a base B in UM1 at a temperature T1 in the range of from

10 to 200 °C, obtaining a mixture M1 comprising an aqueous phase PA(1) and an organic phase Po(1), the pH of the aqueous phase PA(1) of M1 being in the range of from 7.5 to 11;

(11.3) passing the mixture M1 obtained according to (ii.2) in a liquid-liquid separation unit US1 comprised in Z_E, US1 being located downstream of UM1, obtaining a stream FA(1) comprising PA(1) and a stream F1 comprising P_o(1) being the extracted bio-oil;

(11.4) removing F1 from Z_E;

(ill) subjecting the stream F1 provided in (ii) to washing in at least one washing zone Zw, Zw being located downstream of Z_E, obtaining a stream F2 comprising the purified bio-oil; and

2. The process of claim 1 , wherein (ii.2) comprises

(11.2.1) introducing water into UM1 comprised in Z_E;

(11.2.2) bringing in contact, preferably mixing, F0 with water in UM1, obtaining a mixture PM1 comprising water and the bio-oil;

(11.2.3) introducing B into UM1 and bringing in contact, preferably mixing, B with the mixture PM1 obtained in (ii.2.2) in UM1, obtaining a mixture M1 comprising an aqueous phase PA(1 ) and an organic phase Po(1), the pH of the aqueous phase PA(1) of M1 being in the range of from 7.5 to 11, preferably in the range of from 8 to 10; preferably (ii.2) comprises

(11.2.1) introducing water into UM1 comprised in Z_E;

(11.2.2) bringing in contact, more preferably mixing, F0 with water in UM1, obtaining a mixture PM1 comprising water and the bio-oil, wherein the aqueous phase of PM1 having a pH value pH(PM1), more preferably measured by a pH-sensor in UM1;

(11.2.3) adjusting the pH of the aqueous phase of PM1 by introducing B into UM1 by bringing in contact, preferably mixing, B with M1 obtained in (ii.2.2) in UM1, obtaining a mixture M1 comprising an aqueous phase PA(1 ) and an organic phase Po(1 ), the pH of the aqueous phase PA(1 ) of M1 > pH(PM1), the pH of PA(1) being in the range of from 7.5 to 11, more preferably in the range of from 8 to 10.

3. The process of claim 1 , wherein (ii.2) comprises

(ii.2.2') introducing MO obtained according to (ii.2.1') into UM1 and bringing in contact, preferably mixing, F0 with MO in UM1 , obtaining a mixture M1 comprising an aqueous phase P_A(1) and an organic phase Po(1), the pH of the aqueous phase P_A(1) of M1 being in the range of from 7.5 to 11 , preferably in the range of from 8 to 10.

4. The process of any one of claims 1 to 3, wherein bringing in contact, preferably mixing, according to (ii.2) is performed at a temperature T1 in the range of from 10 to 95 °C, preferably in the range of from 15 to 85 °C, more preferably in the range of from 20 to 80 °C, more preferably in the range of from 20 to 50°C.

5. The process of any one of claims 1 to 4, wherein no organic solvent is used in (ii).

6. The process of any one of claims 1 to 5, wherein (ill) comprises:

(ill.1 ) introducing F1 into a washing unit UM2 comprised in Zw;

(111.3) passing the mixture M2 obtained according to (ill.2) in a liquid-liquid separation unit US2 comprised in Zw, US2 being located downstream of UM2, obtaining a stream F_A(2) comprising P_A(2) and a stream F2 comprising P_o(2) being the purified bio-oil, wherein preferably the washing unit UM2 is one or more of a stirred vessel, a mixing pump and a static mixer, more preferably a stirred vessel; and wherein preferably the liquid-liquid separation unit US2 is one or more of a hydrocyclone, a settler tank, a centrifuge and an extraction column, more preferably a hydrocyclone, a settler tank or a centrifuge, more preferably a settler tank or centrifuge.

7. The process of any one of claims 1 to 5, wherein (ill) comprises:

(iii. T) introducing F1 into an extraction column UM+US comprised in Zw;

(ill.2') introducing water into UM+US;

(ill.3') bringing in contact F1 with water in UM+US at a temperature T2' in the range of from 10 to 95 °C, obtaining a stream F_A(2) comprising an aqueous phase P_A(2), the pH of the aqueous phase P_A(2) of M2 being in the range of from 7.5 to 11 , pH of P_A(2) < pH of P_A(1), and obtaining a stream F2 comprising the purified bio-oil.

8. The process of any one of claims 6 to 7, wherein, according to (iii.2) or (iii.3’), the weight ratio of water to F1 is in the range of from 0.05: 1 to 2:1 , preferably in the range of from 0.1 : 1 to 1.5:1 , more preferably in the range of from 0.1 : 1 to 1.2:1 , more preferably in the range of from 0.1 :1 to 0.5:1.

9. The process of any one of claims 6 to 8, further comprising recycling at least a portion of water comprised in F_A(2) obtained according to (iii.3) in (ii.2) and/or (iii.2); or recycling at least a portion of water comprised in F_A(2) obtained according to (iii.3') in (ii.2) and/or (iii.2').

10. The process of any one of claims 1 to 9, further comprising, when crud is formed at the interphase of P_A(1) and Po(1) in US1 , purging said crud from US1 , preferably being a settler tank.

11. The process of any one of claims 1 to 10, wherein the stream F2 comprising the purified bio-oil obtained according to (ill) has a total acid number (TAN) which is lower than the TAN of the bio-oil provided in (I); wherein preferably the stream F2 comprising the purified bio-oil obtained according to (ill) has an oxygen content equal to or lower than, more preferably lower than, the oxygen content of the bio-oil provided in (I).

12. A process for purifying a bio-oil, the process comprising:

(I) according to any of the preceding claims;

(II) according to any of the preceding claims;

(III) according to any of the preceding claims;

(iv) subjecting at least a portion of the stream F2 obtained according to (ill) to one or more subsequent washing in Zw, wherein (iv) comprises:

(iv.1) optionally introducing at least a portion of F2, preferably F2, obtained according to (ill) into a washing unit UM3 comprised in Zw, UM3 being located downstream of US2; bringing in contact the at least portion of F2, preferably F2, with water in UM3 at a temperature T3 in the range of from 10 to 95 °C, obtaining a mixture M3 comprising an aqueous phase P_A(3) and an organic phase Po(3) of M3 being in the range of from 7.5 to 11 , pH of P_A(3) < pH of PA(1); passing the mixture M3 in a liquid-liquid separation unit US3 comprised in Zw, US3 being located downstream of UM3, obtaining a stream F_A(3) comprising P_A(3) and a stream F3 comprising Po(3) being the purified bio-oil;

(iv.2) introducing at least a portion of F2, preferably F2, obtained according to (ill), or at least a portion of F3 obtained according to (iv.1 ), into a washing unit UM4 comprised in Zw, UM4 being located downstream of US3;

(iv.3) bringing in contact the at least portion of F2, or the at least portion of F3, with water in UM4 at a temperature T4 in the range of from 10 to 95 °C, obtaining a mixture M4 comprising an aqueous phase P_A(4) and an organic phase Po(4), the pH of the aqueous phase P_A(4) of M4 being in the range of from 7.5 to 11 , pH of P_A(4) < pH of P_A(1 ); (iv.4) passing the mixture M4 obtained according to (iv.3) in a liquid-liquid separation unit US4 comprised in Zw, US4 being located downstream of UM4, obtaining a stream FA(4) comprising PA(4) and a stream F4 comprising Po(4) being the purified bio-oil; and

(v) introducing F4 obtained according to (iv) into at least one storage unit SU and storing said bio-oil in SU.

13. The process of any one of claims 1 to 12, wherein the storage unit SU is a storage tank, preferably a storage tank made of one or more of steel and stainless steel, more preferably carbon steel and stainless steel.

14. A unit for carrying out the process for purifying a bio-oil according to any one of claims 1 to 13, the unit comprising at least one extraction zone ZE comprising an extraction unit UM1 and a liquid-liquid separation unit US1, UM1 being located upstream of US1; an inlet means for introducing FO into Z_E; an outlet means for removing F1 from ZE; an inlet means for introducing FO into UM1; an outlet means for removing M1 from UM1; an inlet means for introducing M1 into US1; an outlet means from removing F1 from US1; at least one washing zone Zw, located downstream of ZE; an inlet means for introducing F1 into Zw; an outlet means for removing F2 from Z_w; and a storage tank.

15. A purified bio-oil, obtained by a process according to any one of claims 1 to 14, wherein preferably the purified bio-oil of the present invention has a total acid number (TAN) in the range of from 0 to 10 mg KOH/g(oil), more preferably in the range of from 0 to 4 mg KOHZg(oil).