Field of the Invention The present invention relates to a method of and a system for the reactive distillation of bio-crudes, especially the reactive distillation of bio-oil under elevated pressures. The present invention also relates to the integration of the reactive distillation of bio-crude with the further upgrading/utilisation of bio-crude. Background of the Invention

Biomass is the only carbon-containing renewable resource that can be used directly to produce liquid fuels, chemicals and carbon materials. Among various routes of biomass conversion, thermochemical conversion offers many advantages in terms of process productivity and efficiency. Pyrolysis and hydrothermal liquefaction of biomass have attracted great global attention, especially for the production of liquid fuels and chemicals.

The pyrolysis of biomass would produce three main classes of products, including a liquid product called bio-oil, a solid product called biochar and a gaseous product comprising various combustible and non-combustible gases. There are many different pyrolysis technologies and one such technology is the grinding pyrolysis of biomass, disclosed in PCT/AU201 1/000741. Bio-oil is a type of bio-crude and may be biorefined/upgraded into various liquid fuels and chemicals (e.g. using the technology disclosed in PCT/AU2013/000825) as well as solid carbon materials (e.g. using the technology disclosed in PCT/AU2016/000133).

As a product from the (partial) fragmentation of biopolymers and other species in biomass when the biomass is heated to elevated temperatures, bio-oil has exceedingly complex physical and chemical structural features. For example, the species in bio-oil can have a very wide range of molecular mass distribution, ranging from small molecules such as water to partially degraded biopolymers of cellulose, hemicellulose and lignin. The species in bio-oil can have a wide variety of chemical structures, including but not limited to aliphatic, cyclic aliphatic, hydroaromatic, heteroaromatic and aromatic structures, with abundant functional groups such as carboxylic acidic groups, carbonyl groups and phenolic groups. While oxygen-containing structures (e.g. furan- type structures) and functional groups are very abundant in bio-oil, various organic structures containing nitrogen and/or sulphur can also be found in bio-oil. Therefore, bio-oil is very reactive. Various inorganic species that were macro and micro inorganic nutrients for the growth of biomass such as potassium, sodium, magnesium, calcium and various trace elements may also partially volatilise during pyrolysis and become part of the bio-oil. While bio-oil is commonly referred to as a liquid, bio-oil can also have colloidal structures and properties.

Biochar fines and other particulates (e.g. originating from the soil in the biomass feedstock for pyrolysis) may also be found in bio-oil.

The bio-crudes from the hydrothermal liquefaction of biomass or other means of thermochemical conversion of biomass share many features of the bio-oil described above.

The complicated properties and structural features of bio-crudes must be fully considered in developing new technologies for the upgrading or direct utilisation of biocrudes. For example, the lighter species in bio-oil can have very different behaviour from the corresponding heavier species when the bio-oil is hydrotreated to produce liquid fuels and chemicals. Ideally, they should be hydrotreated under very different conditions.

Similarly, the lighter and heavier fractions differ significantly during reforming and have different optimal reforming conditions.

Furthermore, the heavier species may also have different beneficial uses from the lighter species. For example, the heavier species may be better suited as a feedstock for the production of solid carbon materials than the lighter species.

Still furthermore, inorganic species or particulates in bio-oil may impact negatively the optimum performance of bio-oil upgrading or utilisation processes and should be separated out of bio-oil before the bio-oil is upgraded or utilised.

Therefore, there is a need for separating bio-oil into various fractions, e.g. based on their volatility or boiling points (more practically boiling point ranges), together with the removal of inorganic species and particulates. Distillation appears to be a suitable way to carry out such separation. However, due to the high reactivity of bio-oil, excessive coke formation is a major problem when bio-oil is distilled at atmospheric or reduced (vacuum distillation) pressures using the existing technologies. New technologies for separating bio-crude into fractions, e.g. via distillation, with minimised coke formation are necessary.

Summary of the Invention

In accordance with a first aspect of the present invention, there is provided a method of reactively distilling a bio-crude, the method comprising:

providing a bio-crude formed through the heat treatment of a carbonaceous feedstock comprising biomass;

heating the bio-crude under elevated pressures; and reducing the partial pressures of the species originally present in the bio-crude and formed from the reactions of the bio-crude to cause the distillation of the species to form different fractions.

The term“biomass”, as used herein, refers to any material derived from living or recently living organisms, including materials excreted from or by the organisms. Examples include, but are not limited to, lignocellulosic materials originated from plants and manure from animals.

The term“carbonaceous feedstock”, as used herein, is intended to include a variety of carbon-containing renewable and non-renewable feedstock including, but not being limited to, coal (its full coalification rank spectrum), biomass, solid wastes or their mixtures. The solid wastes may include, but are not limited to, agricultural wastes, forestry wastes, industrial wastes, domestic/municipal wastes or residues from the processing of carbonaceous feedstock. These wastes may also be mixed to become a carbonaceous feedstock. In fact, many solid wastes are considered as biomass in the broad sense. Alternatively, biomass is at least a significant component in many solid wastes.

The term“heat treatment”, as used herein, is intended to include, within its scope, any process at elevated temperatures, in the presence or absence of additional substances. For example, the pyrolysis of biomass in an inert, oxidative or reductive atmosphere is a heat treatment process. The hydrothermal treatment of biomass in water (at subcritical or supercritical status or at the critical point) is another type of heat treatment process.

The term“bio-crude”, as used herein, is intended to include any liquid or paste/slurry product from the heat treatment of biomass or other carbonaceous feedstocks. The bio-oil from the pyrolysis of biomass is a typical bio-crude. A bio-crude may include various impurities, including but not being limited to, dissolved inorganic species and particulates. The particulates may contain organic carbon (e.g. biochar fines) or may be mostly inorganics (e.g. soils in the feedstock comprising biomass that end up in the bio-crude).

In an embodiment, the bio-crude is bio-oil from the pyrolysis of the carbonaceous feedstock comprising biomass. In a further particular embodiment, the bio-crude is biooil from the pyrolysis of biomass. In another embodiment, the bio-crude is a product from the hydrothermal liquefaction of the carbonaceous feedstock comprising biomass or from the hydrothermal liquefaction of biomass.

The term“elevated pressure” refers to a pressure level higher than the ambient pressure. Similarly, the term“elevated temperature” refers to a temperature level higher than the ambient temperature. The term“distillation”, as used herein, is intended to include, within its scope, any process in which the components (or substances) in a feedstock for distillation are separated into various fractions that have different boiling point ranges or other properties. The boiling point ranges for various fractions may overlap with each other. After separation, these fractions may be in the forms of vapour (gas), supercritical fluid, liquid, solid or their mixtures such as pastes, slurries and composites. The term “reactive distillation”, as used herein, is intended to include any distillation process in which at least one type of chemical reaction takes place.

The distillation of a bio-crude often involves chemical reactions because of the high reactivity of the bio-crude. Therefore, the distillation of a bio-crude is normally a reactive distillation process. In fact, a bio-oil can undergo complicated chemical reactions, albeit slowly, even if it is stored under ambient conditions. In particular, heating a bio-crude to elevated temperatures can cause a network of chemical reactions to take place in the bio-crude, forming lighter and heavier species. For example, distilling a bio-oil to temperatures higher than 150°C at a pressure close to atmospheric pressure can result in the formation of a fume and a solid residue due to the reactions taking place.

Embodiments of the present invention have significant advantages. In particular, heating a bio-crude (e.g. bio-oil) under pressure greatly reduces the formation of coke or heavy species compared with the heating of the same bio-crude to the same temperature at low pressures such as at atmospheric pressure or reduced pressures (under vacuum).

Without necessarily subscribing to any particular theory, multiple benefits can be achieved by heating the bio-crude under elevated pressures. For example, many chemical species in a bio-oil are polar, largely due to the presence of various oxygen- containing structures in the bio-oil. Water, frequently amounting to 15-35 wt% of a biooil, plays an important role in solubilising various species in the bio-oil, contributing to maintaining the bio-oil as a liquid or liquid-like material. The interactions between water and other bio-oil components include not only van der Waals forces but also other interactions such as H-bonding. These forces are also at least partly responsible for the 3-D structural configuration of macromolecules in the bio-oil. Other light species in the bio-oil also contribute to the solubilisation of heavy species in the same bio-oil. When the bio-oil is heated at low pressures, e.g. close to atmospheric pressure or under some extents of vacuum, water and some light species in the bio-oil would easily evaporate, leaving behind a viscous liquid or solid. However, when the bio-oil is heated under elevated pressures, the evaporation of water and light species would be greatly retarded or inhibited. The presence of water and light species would also dilute the heavy species, helping to slow down the recombination reactions that are responsible for the formation of additional heavier species. Many other reactions may also take place under elevated pressures. For example, the acids in the bio-oil (e.g. formic acid and acetic acid) may catalyse the hydrolysis reactions, which will help to reduce the formation of heavy species. On the contrary, the evaporation of water and light acids during distillation at low pressures will make these reactions such as hydrolysis very difficult or impossible.

The saturated vapour pressure of a material (including mixtures) is a function of temperature. It would be difficult to set a fixed pressure value for the reactive distillation of bio-crude using an embodiment of the present invention. The higher the pressure, the less amounts of bio-crude components would be evaporated. It may be advantageous to maintain the distillation pressure under which a bio-crude is heated at a level higher than the saturated vapour pressure of the bio-crude at any temperature to which the bio-crude is heated.

The step of heating a bio-crude under elevated pressures may be carried out in a variety of ways. In one embodiment, the bio-crude is heated up under the elevated pressures created by the vapour of the bio-crude itself. For example, by limiting the space available for the volatilisation and escaping of the vapour from the bio-crude being heated in a closed vessel (autoclave), the bio-crude can be heated up under elevated pressure.

In another embodiment, the bio-crude is heated up under the elevated pressures created by a pressurised fluid surrounding the bio-crude but having low solubility in the bio-crude liquid. The fluid may be an inert gas or other gases, including their mixtures.

In an additional embodiment, the bio-crude is heated up under the elevated pressures created by a combination of a pressurised fluid and a limited space retarding the volatilisation of the components from the bio-crude.

When the reactive distillation of a bio-crude is integrated with other means of bio-crude upgrading/utilisation, consideration should be given to set the distillation pressure at a level higher than or close to the upgrading/utilisation process. For example, when the reactive distillation is integrated with the hydrotreatment of a bio-crude (see below for more details), the distillation can be carried out at a pressure higher than or close to the pressure of hydrotreatment.

The peak temperature of the bio-crude being distilled is an important factor influencing the extents of separation that will be achieved from the reactive distillation. This can be chosen and set according to the desired products to be obtained from the distillation. In one particular embodiment, in order to achieve a good yield of light species from a biooil, the peak temperature for the distillation of bio-oil is set to a level preferably between 100 and 300°C, more preferably between 150 and 270°C, even more preferably between 150 and 230°C and most preferably between 150 and 210°C, when the operating pressure is around 7 MPa. The choice of a peak temperature is based on the volatility of the species existing in the bio-crude to be distilled as well as the extent of reactions to be achieved. In one embodiment, the peak temperature is set to be low (<150°C) so that the chemical reactions are minimised. Only very light species would be distilled out of the bio-crude. In another embodiment, the peak temperature is set at a medium level (e.g. <230°C) for some very reactive species to react. In yet another embodiment, the peak temperature is set high (e.g. up to 450°) to cause the bio-crude to undergo extensive reactions, including but not being limited to cracking reactions and polymerisation reactions, to result in the formation of a hard solid residue with the reminder portion of the bio-crude being distilled out.

Once the bio-crude has reached the desired peak temperature, the partial pressures of the species originally present in and/or derived from the bio-crude can be reduced to cause distillation. This can be achieved in a number of ways. In one embodiment, the overall system pressure is let down, resulting in the reduction of the partial pressures of all species originally present in and/or derived from the bio-crude. This is normally accompanied by decreases in temperature, which may require means to supply the thermal energy required for the evaporation (latent heat) of volatile species.

In another embodiment, another fluid is mixed with the hot bio-crude and its reaction products to result in the reduction of the partial pressures of all species originally present in and/or derived from the bio-crude. The exact choice of a fluid will depend on the purpose of the reactive distillation. On the one hand, the fluid is preferably gas and more preferably inert gas. On the other hand, a reactive fluid is preferred to carry out some beneficial reactions with the bio-crude component(s). Again, the evaporation of volatile species may cause the system temperature to drop and thus means to supply heat to meet the heat of evaporation may be required.

The volatilised species may be condensed into various fractions having different boiling point ranges although the boiling point ranges of these fractions may overlap with each other. In one embodiment, the condensation may be carried out in steps/stages, as in a conventional distillation column known to those skilled in the art. In an alternative embodiment, condensable volatiles may be condensed into one fraction. The product fractions may be a gas (vapour), a liquid, a solid or their mixtures/composites such as slurries and pastes. For example, due to the reactions taking place during the distillation, lighter species may be formed and thus some products, as a fraction of distillation, may be in a gaseous (vapour) form containing such species as CO2 and CH ₄ .

In accordance with a second aspect of the present invention, there is provided a method of reactively distilling a bio-crude, the method comprising:

providing a bio-crude formed through the heat treatment of a carbonaceous feedstock comprising biomass; providing an additive being capable of reacting with the bio-crude, catalysing and/or inhibiting the reactions involving the bio-crude and/or solubilising the bio-crude and/or its reaction products;

mixing the bio-crude and the additive to form a feed mixture;

heating the feed mixture under elevated pressures; and

reducing the partial pressures of the species originally present in the bio-crude and formed from the reactions of the bio-crude to cause the distillation of the species to form different fractions.

While commonly“catalysing” means the action to speed up a reaction, its broad sense also includes the action to slow down a reaction, i.e.“inhibiting” a reaction. The same catalyst may catalyse some reactions and inhibit other reactions in the same reaction mixture.

In an embodiment, the bio-crude is bio-oil from the pyrolysis of the carbonaceous feedstock comprising biomass. In a further particular embodiment, the bio-crude is biooil from the pyrolysis of biomass. In another embodiment, the bio-crude is a product from the hydrothermal liquefaction of the carbonaceous feedstock comprising biomass or from the hydrothermal liquefaction of biomass.

Compared with the first aspect of the present invention, one of the purposes of introducing an additive in the second aspect of the present invention is to cause the bio-crude to react with the additive when the feed mixture is heated, either by catalysing/initiating new reactions between the bio-crude or by catalysing/inhibiting the inherent reactions involving the bio-crude components at elevated temperatures. The additive may also carry out both functions of catalysing/initiating new reactions and catalysing/inhibiting the inherent reactions involving the bio-crude components.

In one embodiment, the additive is methanol for the reactive distillation of bio-oil from the pyrolysis of biomass. Methanol may be in the form of a liquid (subcritical status), a vapour, a supercritical fluid or at its critical point. Methanol can initiate many reactions with the bio-oil components. For example, methanol can react with the carboxylic acidic groups in the bio-oil to form esters, react with carbonyl groups (e.g. aldehydes) in the bio-oil to form acetals and react with sugars (or oligomers) in the bio-oil to form such products as levulinates. Transesterification with methanol can also take place. Many other reactions, e.g. methanolysis of the olefin, can also take place. Methanol can also at least partly inhibit reactions involving bio-oil that would form heavy species or coke. These reactions between methanol and bio-oil components would contribute to stabilise the bio-oil and reduce coke formation when the bio-oil is heated up. Much of the reactions involving methanol and bio-oil can be catalysed by the acidic components in the bio-oil or externally added acidic species.

In another embodiment, higher alcohols (e.g. ethanol, propanol and butanol or any mixture of them) are used as additives. The additive can also be a mixture. In a further embodiment, a mixture of alcohol, including methanol and/or high alcohols is used as the additive.

In a particular embodiment, the additive mixture is a mixture of alcohol (or alcohol mixture) and acid, where the acid would act as a catalyst for the reactions between alcohols and bio-oil. In an alternative particular embodiment, the additive mixture is a mixture of alcohol (or alcohol mixture) and base, where the base would catalyse the reactions between the alcohols and the bio-oil.

Those skilled in the art would appreciate that many different types of additives, catalysts or their mixture can be used to initiate/catalyse new reactions in the bio-crude and/or inhibit the inherent reactions of the bio-crude at elevated temperatures and pressures, without departing from the inventive nature of the present invention.

Another purpose of introducing an additive is for the additive to act as a solvent or as part of the solvent mixture. In particular, the additive is mainly used to solubilise the heavy species in the bio-crude and/or the heavy species formed from the bio-crude upon heating. This is particularly useful to prevent the distillation system from being blocked or to reduce the extent and/or the frequency of blockage. In a particular embodiment, the additive is acetone. Acetone may be in the form of a liquid or a supercritical fluid or at its critical point during the heating up of the feed mixture, depending upon the conditions of reactive distillation. Those skilled in the art may appreciate that many types of solvents can be used for this purpose by considering the thermal stability, solubility for the heavy species and other factors such as economics. The solubility herein refers to that under the conditions (temperature and pressure) of distillation and not necessarily that under ambient conditions. Consideration may also be given to the recovery of solvent after distillation and thus the re-use of the solvent.

In an embodiment of the first aspect or the second aspect of the present invention, one or more heavier fractions are further thermally treated to produce additional lighter products.

In another embodiment of the first aspect or the second aspect of the present invention, one or more heavier fractions are used as fuels. In a further embodiment, these heavier fractions are blended with additional substance(s) to modify their properties such as viscosity.

There is also a need for integrating such bio-oil separation processes into the overall bio-oil upgrading or utilisation processes for optimum performance and efficiencies. For example and without limiting the scope of the present invention, for a bio-crude to be hydrotreated, the bio-crude must be heated to elevated temperatures at which hydrotreating reactions take place, requiring a significant amount of energy. The presence of water in the bio-crude (e.g. water in bio-oil) means that a substantial amount of energy may be required to evaporate the water in addition to the evaporation of bio-crude species in many hydrotreatment processes. The separation and removal of very heavy species, inorganic species and particulates from the biocrude to be hydrotreated prior to the hydrotreatment can be very advantageous.

Innovation is therefore required to distil the bio-crude with minimised coke formation and integrate the distillation into the overall bio-crude upgrading or utilisation processes. The integration of bio-crude distillation with bio-crude hydrotreatment is one such example. The integration of bio-crude distillation with bio-crude reforming is another such example.

In accordance with a third aspect of the present invention, there is provided a method of reactively distilling a bio-crude, the method comprising:

providing a bio-crude formed through the heat treatment of a carbonaceous feedstock comprising biomass;

heating the bio-crude under elevated pressures;

reducing the partial pressures of the species originally present in the bio-crude and formed from the reactions of the bio-crude to cause the distillation of the species to form different fractions; and

hydrotreating one or more of the said fractions with a hydrogenation agent to produce hydrotreated products.

The terms“hydrotreating” or variations such as“hydrotreat” and“hydrotreatment”, as used herein, refer to any reactions between the bio-crude and a hydrogenation agent, including but not limited to hydrogenation, hydrocracking, hydrodeoxygenation, hydrodesulphurisation and hydrodenitrogenation. These reactions may be catalytic or non-catalytic.

In an embodiment, the bio-crude is bio-oil from the pyrolysis of the carbonaceous feedstock comprising biomass. In a further particular embodiment, the bio-crude is biooil from the pyrolysis of biomass. In another embodiment, the bio-crude is a product from the hydrothermal liquefaction of the carbonaceous feedstock comprising biomass or from the hydrothermal liquefaction of biomass.

In accordance with a fourth aspect of the present invention, there is provided a method of reactively distilling a bio-crude, the method comprising:

providing a bio-crude formed through the heat treatment of a carbonaceous feedstock comprising biomass;

providing an additive being capable of reacting with the bio-crude;

mixing the bio-crude and the additive to form a feed mixture;

heating the feed mixture under elevated pressures; and

reducing the partial pressures of the species originally present in the bio-crude and formed from the reactions of the bio-crude to cause the distillation of the species to form different fractions; and

hydrotreating one or more fractions to produce hydrotreated products. In an embodiment, the bio-crude is bio-oil from the pyrolysis of the carbonaceous feedstock comprising biomass. In a further particular embodiment, the bio-crude is biooil from the pyrolysis of biomass. In another embodiment, the bio-crude is a product from the hydrothermal liquefaction of the carbonaceous feedstock comprising biomass or from the hydrothermal liquefaction of biomass.

In one embodiment of both the third and fourth aspects of the present invention, the hydrogenation agent is hydrogen gas. Compared with the first and second aspects of the present invention respectively, the third and fourth aspects of the present invention introduce an additional step of hydrotreating one or more fractions from the reactive distillation of a bio-crude.

Embodiments of the present invention provides means of beneficial integration of reactive distillation with the upgrading of bio-crude, with hydrotreatment being an example of the upgrading processes. This may have significant advantages over the direct upgrading (hydrotreatment) of bio-crude, which will be explained below using bio-oil as an example of bio-crude:

(a), In a preferred embodiment, the hydrogen gas used for hydrotreatment can serve as a fluid to reduce the partial pressure of the species originally present in and/or derived from the bio-crude to effect the distillation.

(b), Bio-oil can contain inorganic species (e.g. K, Mg and Ca salts or carboxylates) and particulates (including biochar fines). These inorganic species and particulates can impact negatively on the hydrotreatment process, e.g. by plugging the catalyst bed or poisoning the catalyst. These inorganic species and particulates have very limited volatility and can be effectively separated from the organic components of the bio-oil during the reactive distillation of the bio-oil. In a preferred embodiment, the hydrotreatment of organic components of bio-oil is carried out without the negative effects of these inorganics and particulates.

(c), The heavy species and light species of a bio-oil can be distilled into different fractions and hydrotreated separately under their optimum hydrotreating conditions. In one embodiment, bio-oil is distilled into two fractions: a heavier fraction comprising the very heavy organic species, inorganic species and particulates and a lighter fraction containing lighter species of the bio-oil. The lighter fraction can be hydrotreated under very different conditions from those for the heavy fraction. In an alternative embodiment, only the lighter fraction is hydrotreated with the heavier fraction to be recovered for other purposes.

(d), In a preferred embodiment, the fraction to be hydrotreated, in its vapour form, is fed directly into the hydrotreatment reactor without being condensed. This means that the heat required for the heating up of bio-oil and the evaporation of water and organic species can be supplied during the reactive distillation, reducing the heat demand at the entrance of the hydrotreatment reactor, allowing the bio-crude vapour fraction to be hydrotreated to be heated up rapidly in the presence of a hydrotreating catalyst to the hydrotreating reaction temperatures, minimising the coke formation, according to a hydrotreatment technology disclosed in PCT/AU2013/000825.

(e), In an embodiment, an alcohol (e.g. methanol) is added into the bio-oil during distillation. The alcohol effectively reacts with many reactive functional groups in the bio-oil to stabilise the bio-oil. The stabilisation of bio-oil helps to reduce the formation of coke during hydrotreatment.

(f), In a further embodiment, the reactive distillation can be further integrated with the hydrotreatment. As an example, lighter and heavier fractions are separated within the corresponding hydrotreatment reactor hydrotreating at least one of the separated fractions wherein the initial section of the hydrotreatment reactor carries out the separation function.

In an embodiment of the third aspect or the fourth aspect of the present invention, the system further comprises one of more reactors to which one or more heavier fractions are further thermally treated to produce additional lighter products that are further hydrotreated.

In accordance with a fifth aspect of the present invention, there is provided a method of reactively distilling a bio-crude, the method comprising:

providing a bio-crude formed through the heat treatment of a carbonaceous feedstock comprising biomass;

heating the bio-crude under elevated pressures;

reducing the partial pressures of the species originally present in the bio-crude and formed from the reactions of the bio-crude to cause the distillation of the species to form different fractions; and

reforming one or more fractions to produce reformed products.

The term“reforming”, as used herein, refers to the reactions converting a bio-crude or its fractions, through their reactions with a reforming agent, into lighter products, which are commonly gases. A synthesis gas mainly comprising CO and H2 is a commonly targeted product. The reforming agent may be steam, air, oxygen, carbon dioxide, hydrogen or a mixture containing any two or more of them. In an embodiment, the bio-crude is bio-oil from the pyrolysis of the carbonaceous feedstock comprising biomass. In a further particular embodiment, the bio-crude is biooil from the pyrolysis of biomass. In another embodiment, the bio-crude is a product from the hydrothermal liquefaction of the carbonaceous feedstock comprising biomass or from the hydrothermal liquefaction of biomass.

In accordance with a sixth aspect of the present invention, there is provided a method of reactively distilling a bio-crude, the method comprising:

providing a bio-crude formed through the heat treatment of a carbonaceous feedstock comprising biomass; providing an additive being capable of reacting with the bio-crude;

mixing the bio-crude and the additive to form a feed mixture;

heating the feed mixture under elevated pressures; and

reducing the partial pressures of the species originally present in the bio-crude and formed from the reactions of the bio-crude to cause the distillation of the species to form different fractions; and

reforming one or more fractions to produce reformed products.

In an embodiment, the bio-crude is bio-oil from the pyrolysis of the carbonaceous feedstock comprising biomass. In a further particular embodiment, the bio-crude is biooil from the pyrolysis of biomass. In another embodiment, the bio-crude is a product from the hydrothermal liquefaction of the carbonaceous feedstock comprising biomass or from the hydrothermal liquefaction of biomass.

By removing the inorganic species, particulates and very heavy species through the reactive distillation of bio-crude, many beneficial outcomes can be achieved during reforming, including the reduced coke formation, reduced poisoning of catalyst (if used in a catalytic reforming process) and reduced plugging of the catalyst bed as well as increased product quality.

The third to sixth aspects of the present invention merely serve as examples of integrating the reactive distillation with the further upgrading or utilisation of the biocrude. In addition to the hydrotreatment and reforming used as examples in the third to sixth aspects of the present invention, the reactive distillation of the present invention may be integrated with many other ways of bio-crude upgrading and utilisation, which would be within the scope of the present invention.

In accordance with a seventh aspect of the present invention, there is provided a system for reactively distilling a bio-crude, the system comprising:

at least one inlet for feeding a bio-crude formed through the heat treatment of a carbonaceous feedstock comprising biomass into a distillation reactor that is capable of being pressurised;

a heat source and means for heating up the bio-crude under elevated pressures in the distillation reactor to form a product mixture comprising the reaction products and unreacted components;

at least one outlet for the product mixture to exit the distillation reactor to enter an evaporation vessel;

means to reduce the partial pressures of the components in the product mixture so that the volatile species in the product mixture evaporate to form one or more condensed phases and a vapour phase.

In an embodiment, the bio-crude is bio-oil from the pyrolysis of the carbonaceous feedstock comprising biomass. In a further particular embodiment, the bio-crude is biooil from the pyrolysis of biomass. In another embodiment, the bio-crude is a product from the hydrothermal liquefaction of the carbonaceous feedstock comprising biomass or from the hydrothermal liquefaction of biomass.

The distillation reactor may take various shapes. In one embodiment, the distillation reactor is a coil or a series of coils. A coil, or a series of coils, is advantageous in terms of providing a large amount of heat transfer area to heat up the bio-crude under elevated pressures inside the distillation reactor.

The heat can be provided to the distillation reactor in a variety of ways. In one embodiment, the coil or the series of coils are immersed in a heating medium. In one example, the heating medium may be a fluid in which the distillation reactor (e.g. the coil or the series of coils) is immersed, as in a heat exchanger. In another example, the heating medium is a bed (bath) of fluidised sand in which the distillation reactor (e.g. the coil or the series of coils) is immersed.

In one embodiment, the partial pressures of the components in the product mixture are reduced using a pressure letdown valve or an orifice through which the product stream flows in a controllable manner. The extent of pressure reduction is controlled by the amount of the opening of the letdown valve or the size of the orifice. In a particular embodiment, the pressure letdown valve or the orifice is installed in between the distillation reactor and the evaporation vessel.

In another embodiment, an additional fluid is introduced for the additional fluid to mix with and dilute the product mixture to reduce the partial pressures of the components in the product mixture. In this case, the system further comprises another inlet and/or a mixer. In a particular embodiment, the additional fluid is a gas.

On reducing the partial pressures of the components in the product mixture, the volatile compounds would evaporate in the evaporation vessel. The evaporation is normally an endothermic process. It is advantageous to supply heat to the evaporation vessel. The evaporation vessel may take a variety of shapes. In one embodiment, the evaporation vessel is a coil or a series of coils. The coil or the series of coils are advantageous to provide large heat transfer surface areas to supply heat into the evaporation vessel. The amount of heat to be supplied will depend on the extent of separation to be achieved. A higher evaporation vessel temperature would tend to have more components evaporated than a lower evaporation vessel temperature.

In a further embodiment, the distillation reactor and the evaporation vessel are the same vessel. In this case, the distillation reactor may not have a separate physical outlet. In a particular embodiment wherein the distillation reactor is a coil, the additional fluid is introduced into the coil at a point downstream the inlet of the coil. The introduction of the additional fluid divides the coil into two portions: the first portion of the coil is used as the distillation reactor and the second portion is used as the evaporation vessel. There may be more than one such points to introduce the additional fluid.

In some applications, the distillation of a bio-crude into condensed phases and a vapour phase in the evaporation vessel may be sufficient. Of course, the system may further comprise means to cool and condense the volatile phase. In other applications, it may be necessary to produce fractions having narrower boiling point ranges (when condensed) than the volatile phase initially produced in the evaporation vessel. For this reason, the system further comprises means to cool and condense the volatile phase into more than one fractions. In a particular embodiment, the volatile phase initially formed undergoes gradual cooling and condensing for the condensates to be collected into different fractions having different boiling point ranges. Those skilled in the art of distillation would appreciate that various means such as distillation trays, together with corresponding cooling means, may be used for this purpose. These also include corresponding means to realise reflux to improve the separation efficiency.

In accordance with an eighth aspect of the present invention there is provided a system for reactively distilling a bio-crude, the system comprising:

at least one inlet for feeding a mixture comprising a bio-crude formed through the heat treatment of a carbonaceous feedstock comprising biomass and an additive into a distillation reactor that is capable of being pressurised;

a heat source and means for heating up the bio-crude under elevated pressures in the distillation reactor to form a product mixture comprising the reaction products and unreacted components;

at least one outlet for the product mixture to exit the distillation reactor to enter an evaporation vessel;

means to reduce the partial pressures of the components in the product mixture so that the volatile species in the product mixture evaporate to form one or more condensed phases and a vapour phase.

In accordance with a ninth aspect of the present invention there is provided a system for reactively distilling a bio-crude, the system comprising:

at least one inlet for feeding a bio-crude formed through the heat treatment of a carbonaceous feedstock comprising biomass into a distillation reactor that is capable of being pressurised;

at least another inlet for feeding an additive into the distillation reactor;

a heat source and means for heating up the bio-crude under elevated pressures in the distillation reactor to form a product mixture comprising the reaction products and unreacted components;

at least one outlet for the product mixture to exit the distillation reactor to enter an evaporation vessel;

means to reduce the partial pressures of the components in the product mixture so that the volatile species in the product mixture evaporate to form one or more condensed phases and a vapour phase. The eighth and ninth aspects of the present invention differ from the seventh aspect mainly in that an additive is fed into the distillation reactor. The additive may carry out any or all of the following functions:

(a), initiating and participating in new reactions with the components in the bio- crude when the bio-crude is heated under elevated pressures in the distillation reactor,

(b), catalysing and/or inhibiting the inherent reactions involving the bio-crude when the bio-crude is heated under elevated pressures in the distillation reactor, and/or

(c), solubilising (acting as a solvent) the heavy species present in the bio-crude and/or formed from the components in the bio-crude in the distillation reactor.

In various embodiments, the additive is a mixture of more than one chemical compounds.

The ninth aspect of the present invention differs from the eighth aspect in that the additive is not mixed with the bio-crude before they are fed into the distillation reactor and that the inlet for the additive may be further downstream of the inlet for the biocrude or vice versa.

The description related to the seventh aspect and relevant embodiments associated with the seventh aspect also applies to the eighth and ninth aspects of the present invention.

In an embodiment of any of the seventh to ninth aspects of the present invention, the system further comprises a reactor into which one or more heavier fractions are fed for thermal treatment to produce additional lighter products.

In accordance with a tenth aspect of the present invention there is provided a system for reactively distilling a bio-crude, the system comprising:

at least one inlet for feeding a bio-crude formed through the heat treatment of a carbonaceous feedstock comprising biomass into a distillation reactor that is capable of being pressurised;

a heat source and means for heating up the bio-crude under elevated pressures in the distillation reactor to form a product mixture comprising the reaction products and unreacted components;

at least one outlet for the product mixture to exit the distillation reactor to enter an evaporation vessel;

means to reduce the partial pressures of the components in the product mixture so that the volatile species in the product mixture evaporate to form different fractions; means for at least one of the said fractions to enter a hydrotreatment reactor containing a hydrotreating catalyst to be hydrotreated therein to form hydrotreated products, and the hydrotreatment reactor having means for accepting at least one hydrogenation agent and at least one outlet for discharging the hydrotreated products and unconverted hydrotreatment reactants.

In accordance with an eleventh aspect of the present invention there is provided a system for reactively distilling a bio-crude, the system comprising:

at least one inlet for feeding a mixture comprising a bio-crude formed through the heat treatment of a carbonaceous feedstock comprising biomass and an additive into a distillation reactor that is capable of being pressurised;

a heat source and means for heating up the bio-crude under elevated pressures in the distillation reactor to form a product mixture comprising the reaction products and unreacted components;

at least one outlet for the product mixture to exit the distillation reactor to enter an evaporation vessel;

means to reduce the partial pressures of the components in the product mixture so that the volatile species in the product mixture evaporate to form different fractions; means for at least one of the said fractions to enter a hydrotreatment reactor containing a hydrotreating catalyst to be hydrotreated therein to form hydrotreated products, and

the hydrotreatment reactor having means for accepting at least one hydrogenation agent and at least one outlet for discharging the hydrotreated products and unconverted hydrotreatment reactants.

In accordance with a twelfth aspect of the present invention there is provided a system for reactively distilling a bio-crude, the system comprising:

at least one inlet for feeding a bio-crude formed through the heat treatment of a carbonaceous feedstock comprising biomass into a distillation reactor that is capable of being pressurised;

at least another inlet for feeding an additive into the distillation reactor;

a heat source and means for heating up the bio-crude under elevated pressures in the distillation reactor to form a product mixture comprising the reaction products and unreacted components;

at least one outlet for the product mixture to exit the distillation reactor to enter an evaporation vessel;

means to reduce the partial pressures of the components in the product mixture so that the volatile species in the product mixture evaporate to form different fractions; means for at least one of the said fractions to enter a hydrotreatment reactor containing a hydrotreating catalyst to be hydrotreated therein to form hydrotreated products, and

the hydrotreatment reactor having means for accepting at least one hydrogenation agent and at least one outlet for discharging the hydrotreated products and unconverted hydrotreatment reactants. In a preferred embodiment of any of the tenth to twelfth aspects of the present invention, the system further comprises at least one means to heat up the said fraction in the hydrotreatment reactor only when the said fraction is in contact with the hydrotreating catalyst that has been heated to a hydrotreatment reaction temperature at which the catalyst can provide activated hydrogen for the hydrotreatment reactions to take place. In a further preferred embodiment, the means to heat up the said fraction to be hydrotreated is by mixing the said fraction with a hot stream of the hydrogenation agent, which may be hydrogen.

In an embodiment of any of the tenth to twelfth aspects of the present invention, the means for accepting the hydrogenation agent into the hydrotreatment reactor is the same inlet for the said fraction to be hydrotreated wherein the said fraction and the hydrogenation agent are rapidly mixed. In an alternative embodiment, the means for accepting the hydrogenation agent into the hydrotreatment reactor is different from the inlet for the said fraction to be hydrotreated.

In an embodiment of any of the eleventh and twelfth aspects of the present invention, the additive, which may be a single compound or a mixture, carries out any or all the functions of reacting with the bio-crude, catalysing/inhibiting the reactions of the biocrude or solubilising the bio-crude and/or its reaction products during distillation. In a further embodiment, the additive takes part in the hydrotreating reactions during the hydrotreatment.

In an embodiment of any of the tenth to twelfth aspects of the present invention, the reduction of the partial pressures of the components in the product mixture is achieved with any or a combination of a pressure letdown valve and the introduction of an additional fluid. Importantly, in a preferred embodiment, the additional fluid is the hydrogenation agent. The hydrogenation agent may be hydrogen gas.

In an embodiment of any of the tenth to twelfth aspects of the present invention, each of the systems may further comprise one or more hydrotreatment reactors for the hydrotreatment of other fractions formed during distillation.

In a further embodiment of any of the tenth to twelfth aspects of the present invention, each of the systems may further comprise means to cool and condense the volatile phase into more than one fractions and means for each of the fractions to move into a different hydrotreatment reactor to be hydrotreated therein.

In a still further embodiment of any of the tenth to twelfth aspects of the present invention, the hydrogenation agent comprises one or more H-donating compounds that can donate activated hydrogen in the hydrotreatment reactor. In a further particular embodiment, the hydrogenation agent comprises one or more compounds that can produce radicals to stabilise the broken bonds in the hydrotreatment reactor. In a particular embodiment, the hydrogenation agent comprises the hydrotreated products, which are recycled. In a further particular embodiment, the hydrogenation agent comprises hydrogen gas.

In a yet still further embodiment of any of the tenth to twelfth aspects of the present invention, the lighter and heavier fractions are separated within the corresponding hydrotreatment reactor hydrotreating at least one of the separated fractions wherein the initial section of the hydrotreatment reactor carries out the separation function.

In an even further embodiment of any of the tenth to twelfth aspects of the present invention, the system further comprises a reactor into which one or more heavier fractions are fed for thermal treatment to produce additional lighter products that are further hydrotreated.

In an embodiment of any of the tenth to twelfth aspects of the present invention, the bio-crude is bio-oil from the pyrolysis of the carbonaceous feedstock comprising biomass. In a further particular embodiment, the bio-crude is bio-oil from the pyrolysis of biomass. In another embodiment, the bio-crude is a product from the hydrothermal liquefaction of the carbonaceous feedstock comprising biomass or from the hydrothermal liquefaction of biomass.

In accordance with a thirteen aspect of the present invention there is provided a system for reactively distilling a bio-crude, the system comprising:

at least one inlet for feeding a bio-crude formed through the heat treatment of a carbonaceous feedstock comprising biomass into a distillation reactor that is capable of being pressurised;

a heat source and means for heating up the bio-crude under elevated pressures in the distillation reactor to form a product mixture comprising the reaction products and unreacted components;

at least one outlet for the product mixture to exit the distillation reactor to enter an evaporation vessel;

means to reduce the partial pressures of the components in the product mixture so that the volatile species in the product mixture evaporate to form different fractions; means for at least one of the said fractions to be reformed to enter a reforming reactor to be reformed therein to form a reformed product gas; and

the reforming reactor having at least one inlet for accepting at least one reforming agent and at least one outlet for discharging the reformed products and unconverted reforming reactants.

In accordance with a fourteenth aspect of the present invention there is provided a system for reactively distilling a bio-crude, the system comprising:

at least one inlet for feeding a mixture comprising a bio-crude formed through the heat treatment of a carbonaceous feedstock comprising biomass and an additive into a distillation reactor that is capable of being pressurised; a heat source and means for heating up the bio-crude under elevated pressures in the distillation reactor to form a product mixture comprising the reaction products and unreacted components;

at least one outlet for the product mixture to exit the distillation reactor to enter an evaporation vessel;

means to reduce the partial pressures of the components in the product mixture so that the volatile species in the product mixture evaporate to form different fractions; means for at least one of the said fractions to be reformed to enter a reforming reactor to be reformed therein to form a reformed product gas; and

the reforming reactor having at least one inlet for accepting at least one reforming agent and at least one outlet for discharging the reformed products and unconverted reforming reactants.

In accordance with a fifteenth aspect of the present invention there is provided a system for reactively distilling a bio-crude, the system comprising:

at least one inlet for feeding a bio-crude formed through the heat treatment of a carbonaceous feedstock comprising biomass into a distillation reactor that is capable of being pressurised;

at least another inlet for feeding an additive into the distillation reactor;

a heat source and means for heating up the bio-crude under elevated pressures in the distillation reactor to form a product mixture comprising the reaction products and unreacted components;

at least one outlet for the product mixture to exit the distillation reactor to enter an evaporation vessel;

means to reduce the partial pressures of the components in the product mixture so that the volatile species in the product mixture evaporate to form different fractions; means for at least one of the said fractions to be reformed to enter a reforming reactor to be reformed therein to form a reformed product gas; and

the reforming reactor having at least one inlet for accepting at least one reforming agent and at least one outlet for discharging the reformed products and unconverted reforming reactants.

In an embodiment of any of the fourteenth and fifteenth aspects of the present invention, the additive, which may be a single compound or a mixture, carries out any or all the functions of reacting with the bio-crude, catalysing/inhibiting the reactions of the bio-crude, solubilising the bio-crude and/or its reaction products during distillation or taking part in the reforming reactions during the reforming.

In an embodiment of any of the thirteenth to fifteenth aspects of the present invention, the reduction of the partial pressures of the components in the product mixture can be achieved with any or a combination of a pressure letdown valve and the introduction of an additional fluid. Importantly, in a preferred embodiment, the additional fluid is part of the reforming agent, which may comprise steam. In an embodiment of any of the thirteenth to fifteenth aspects of the present invention, the bio-crude is bio-oil from the pyrolysis of the carbonaceous feedstock comprising biomass. In a further particular embodiment, the bio-crude is bio-oil from the pyrolysis of biomass. In another embodiment, the bio-crude is a product from the hydrothermal liquefaction of the carbonaceous feedstock comprising biomass or from the hydrothermal liquefaction of biomass.

In an embodiment of any of the thirteenth to fifteenth aspects of the present invention, the reforming agent is one or more of H ₂ 0 (steam), C0 ₂ , air, oxygen or H ₂ .

In a further embodiment of any of the thirteenth to fifteenth aspects of the present invention, the system further comprises one or more reforming reactors for the reforming of other fractions formed during distillation. This allows the different distillation fractions to be reformed under different conditions.

Brief Description of the Drawings

Embodiments of the present invention will now be described, by way of examples only, with reference to the accompanying figures, in which:

Figures 1 is a flow diagram of a method of and system for reactively distilling a bio-crude in accordance with an embodiment of the present invention;

Figure 2 is a flow diagram of a method of and system for reactively distilling a bio-crude in accordance with another embodiment of the present invention;

Figure 3 is a flow diagram of a method of and system for reactively distilling a bio-crude in accordance with a further embodiment of the present invention; and

Figures 4 is a flow diagram of a method of and system for reactively distilling a bio-crude in accordance with a still further embodiment of the present invention.

Detailed Description of Example Embodiments of the Present Invention

Embodiments of the present invention relate to a method of and system for the reactive distillation of bio-crude. It should be emphasised that the present invention can be practiced in batch operations or in continuous operations. Some example

embodiments illustrating the present invention will be explained below, with a special focus on the continuous operation. However, the present invention is not limited to these embodiments.

Figure 1 shows a method of and system 100 for the reactive distillation of a bio-crude to produce lighter and heavier fractions. Bio-oil from the pyrolysis of biomass is used as the bio-crude to illustrate the specific embodiments.

Bio-oil can be produced from the pyrolysis of a wide variety of biomass resources using many pyrolysis technologies. In this embodiment, the bio-oil is produced from the grinding pyrolysis of mallee biomass according to the technology disclosed in

PCT/AU201 1/000741 .

The bio-oil 101 to be distilled is stored in a refillable tank 105. A high pressure pump 110 is used to feed the bio-oil 101 into a distillation reactor 125. The distillation reactor 125 is capable of being pressurised. In one example, it is pressurised to 7 MPa when in use. The operation pressure can be over a wide range. The distillation reactor 125 is therefore preferably constructed using steel. In an embodiment, the distillation reactor 125 is made of a coil or a series of coils. This has significant advantages because a coil structure provides a large heat transfer surface area while it can sustain high pressure. In an alternative embodiment, a bank of tubes are used, similar to the arrangement in a shell-and-tube exchanger.

The distillation reactor 125 is heated by being immersed in a bath/bed of fluidised sand 130. The fluidised sand bath 130 has an excellent ability to provide a relatively uniform temperature distribution inside the bed. As the bio-oil flows through the distillation reactor 125, it will be heated up indirectly by the sand. In an alternative embodiment, a bank of tubes serve as the distillation reactor and are heated up using a hot fluid in an arrangement similar to that in a shell-and-tube heat exchanger.

As will be explained later, a back pressure regulator 198 is used to maintain the system pressure. As the bio-oil 101 is heated up in the distillation reactor 125 under elevated pressures, reactions involving the bio-oil will take place to form a product mixture comprising the reaction products and unreacted components. The product mixture then exits the distillation reactor 125 as a stream 126.

In an embodiment, an additional fluid 135 is used to reduce the partial pressures of the components in the product mixture. The fluid 135 is supplied from a high pressure source and its pressure is then regulated with a pressure regulator 140 to the desired pressure level before its flow rate is measured with a flow metering device 145. The fluid 135 then enters heater 150, which is a coil or a series of coils 150, to be heated up. In an alternative embodiment, the heater 150 can be a bank of tubes or any other suitable apparatus. The coil 150 is heated by being immersed in the fluidised sand bath (130) that also houses and heats up the distillation reactor 125. In an alternative embodiment, a separate means (e.g. another fluidised sand bed or a shell-and-tube heat exchanger) is used to heat up the fluid 135. In one embodiment, the fluid is a gas. In a preferred embodiment, the fluid is hydrogen.

The heated fluid 135 exiting the coil 150 mixes with the hot product mixture 126 exiting the distillation reactor 125 to form a new stream 151 that then enters the evaporation vessel 155. On mixing, the fluid 135 would dilute the product mixture 126 to cause the partial pressures of the components therein to reduce: therefore some limited extent of evaporation may take place as soon as the mixing happens. However, by controlling the conditions carefully (especially a short time for mixing), the evaporation mainly takes place in the evaporation vessel 155. The evaporation is an endothermic process. In one embodiment, the evaporation vessel is made into the shape of a coil or a series of coils 155, which is heated by being immersed in the fluidised sand bath 130. The fluidised sand bath for the evaporation vessel 155, that for the distillation reactor 125 and that for the heater 150 may be the same or different. This arrangement effectively supplies the heat for evaporation to maintain the evaporation operation temperature. In an alternative embodiment, the evaporation vessel is in the form of a bank of tubes in an arrangement similar to the shell-and-tube heat exchangers. The evaporation vessel can be any suitable apparatus.

Following evaporation in the evaporation vessel 155, the stream 156 exiting the vessel 155 may comprise multiple phases, which then enters a separator 160. The condensed phases 164 from the separator 160 is discharged from a valve 165 as a stream 166 while the vapour phase exits the separator 160 as a stream 167. The temperature of the separator 160 needs to be controlled well. In one embodiment, the separator 160 is maintained at the same temperature as the evaporation vessel 155. In a particular embodiment, the distillation reactor 125, the heater 150, the evaporation vessel 155 and the separator 160 are all immersed in the same fluidised sand bath 130. In another embodiment, the separator is maintained at a temperature different from (e.g. lower than) that of the distillation vessel 155 using another fluidised sand bath or other means.

In one embodiment, the stream 167 is condensed together as one fraction (except from some small amounts of uncondensed gaseous products and the uncondensed components in fluid 135). In another embodiment, the stream 167 can undergo stepwise cooling and condensation in separators 170, 180 and 190 to produce condensed products and discharged via valves 175, 185 and 195 as streams 176, 186 and 196 respectively. Many means of cooling known to those skilled in the art can be used (details not shown in Figure 1). Streams 177 and 187 are intermediate volatile streams. The stream 197 would contain uncondensed gaseous products and uncondensed components in fluid 135. After going through the back pressure regulator

198, the uncondensed species would be discharged from the system 100 as a stream

199. There can be any reasonable number of separation stages with appropriate separators (e.g. 160, 170, 180 and 190) and inter-stage cooling (not shown) to produce product fractions (e.g. 166, 167, 176, 177, 186, 187, 196 and 197).

In a further embodiment, the separators and inter-stage cooling can be replaced by a conventional distillation column, which is known by those skilled in the art. The distillation column can be operated at various pressures when pressure letdown devices (e.g. valves) are used.

Now turn back to the distillation reactor 125. The use of the back pressure regulator 198 maintains the distillation reactor at elevated pressures. Inside the distillation reactor 125 (before the product stream 126 mixes with the fluid 135 after being heated in the heater 150), the evaporation of lighter species is greatly retarded, allowing the desired reactions between the lighter and heavier species to take place.

In an embodiment, the system 100 further comprises one or more reactors (not shown in Figure 1) into which one or more heavier fractions are fed for thermal treatment to produce additional lighter products. The lighter products can be collected separately or join any of the streams 167, 177, 187 and 197.

In some applications, the heavier fractions (any of the streams 166, 176, 186 and 196) may be used as a fuel. Additional substances (e.g. methanol or other solvents) can be blended with the heavier fractions to alter the fuel properties such as viscosity and ignition characteristics.

The system 100 also comprises the means to introduce an additive 1 14. In one embodiment, the additive 1 14 is pumped (120) from its refillable storage tank 1 15 to mix with the bio-oil 101 to form a feed mixture 123. The feed mixture 123 then enters the distillation reactor 125.

The additive 1 14 can carry out any or all of the following functions: as a reactant to react with the bio-oil, as a catalyst/inhibitor to catalyse/inhibit the inherent reactions of the bio-oil in the distillation reactor under the conditions of elevated temperatures and pressures or as a solvent to solubilise the heavier species present in the distillation reactor.

The additive 1 14 can be a mixture of various materials to carry out the above- mentioned functions.

In a further embodiment (not shown in Figure 1), the additive 1 14 is introduced into the distillation reactor at a point downstream the inlet of the distillation reactor.

In a still further embodiment (not shown in Figure 1 ), the additive 1 14 is introduced after the distillation reactor, e.g. to mix with the product mixture 126.

In a yet still further embodiment (not shown in Figure 1), the additive 1 14 is introduced in any or all the manners mentioned above: before the distillation reactor 125, at a point downstream the inlet of the distillation reactor 125 and/or after the exit of the distillation reactor 125.

In a particular embodiment, the additive 1 14 is methanol. In another particular embodiment, the additive 1 14 is acetone. In a further embodiment, the additive is a mixture of acetone and methanol.

Figure 2 shows a method of and system 200 for the reactive distillation of a bio-crude to produce lighter and heavier fractions, integrated with the hydrotreatment of the fractions. Bio-oil from the pyrolysis of biomass is used as the bio-crude to illustrate the specific embodiments.

Many numerals in Figure 2 (method and system 200) are the same as those in Figure 1 (method and system 100) and have the same functions as those in system 100.

The lighter fraction 167 produced from the reactive distillation of bio-oil 101 is fed directly into a hydrotreatment reactor 210 containing a catalyst 230 to produce a hydrotreated product stream 215. The catalyst 230 can be a mixture of catalysts. The hydrotreatment reactor may contain different catalysts at different locations, e.g.

different catalysts in different sections along the direction of material flow in the reactor. In an embodiment, the hydrogenation agent stream 220 is also fed into the

hydrotreatment reactor. In a particular embodiment, the hydrogenation agent is hydrogen gas. In a further particular embodiment, the streams 167 and 220 are mixed rapidly at the beginning of a cone that forms the inlet section of the hydrotreatment reactor 210. Many different hydrotreatment technologies may be suitable although a particularly suitable one is that disclosed in PCT/AU2013/000825.

In agreement with the teaching by PCT/AU2013/000825, the lighter fraction 167 should be heated up rapidly in the presence of a catalyst 230 that has already been at an elevated temperature and is active in providing activated hydrogen. This elevated temperature mentioned here may be in the range of the hydrotreatment temperatures. To achieve the rapid heating of the stream 167, the stream 220 is overheated, i.e. above the hydrotreatment temperatures, so that its thermal energy can be transferred to the material in the stream 167 as they mix in the presence of the catalyst 230.

In another embodiment, the stream 220 may be a mixture, e.g. comprising the hydrogen gas and other components. In one particular embodiment, the stream contains hydrogen-donating agents. In a further embodiment, the hydrogen donating agents are the hydrotreated products. For example, part of the hydrotreatment product stream 215 or part of the streams 257 or 267 may be recycled (not shown in Figure 2) and become part of the stream 220. The hydrogen-donating agents, e.g. containing hydroaromatics and/or cyclic aliphatics, can react with some components in the stream 167 to donate activated hydrogen to the components in the stream 167. For example, the chemical bonds in the components in the stream 167 may break as the stream is heated up on mixing with the stream 220 and/or in the hydrotreatment reactor 210. The hydrogen-donating agents in the stream 220 can then donate activated hydrogen to stabilise the broken bonds (which can be part of the hydrotreatment reactions) while the hydrogen-donating agents are dehydrogenated. The dehydrogenated hydrogen- donating agents can then be re-hydrogenated on the catalyst surface to continue the hydrogen donating process. In this way, the hydrogen-donating agents can act as “hydrogen shuttles” to transfer hydrogen in the hydrogenation agent, via the catalyst 230, to the components in the stream 167 that are to be hydrotreated. This hydrogen shuttling process can be particularly useful for the heavy molecules in the stream 167 that have difficulties, due to their sizes, to access the active sites on/in the catalyst, especially the active sites in the micro-pores in the catalyst. Therefore, the hydrogen shuttling process can greatly help to reduce the formation of coke, particularly due to the heavy components in the bio-oil that have remained in the stream 167, in the hydrotreatment reactor 210.

The stream 220 can also contain materials that may react to produce other types of activated species, e.g. methyl radicals. These radicals can also stabilise the broken bonds in the components in the stream 167.

The additive 1 14 can be chosen to have abilities to donate hydrogen or produce other activated species as mentioned above.

The hydrotreatment reactions are strongly exothermic, which can result in a“runaway” status where the temperature in the hydrotreatment reactor become exceedingly and dangerously high. This reaction heat must be removed to maintain the reaction temperature in the desired range. In one embodiment, a heat-exchange means 235 is installed inside the hydrotreatment reactor. In one particular embodiment, this heat- exchange means is a coil or a series of coils 235 in the hydrotreatment reactor. A heat exchange medium 240 flows through the coil 235 to take the heat away. The heat exchange medium may enter from upper or lower inlet. The heat exchange coil 235 also plays an important role in providing heat to the inlet section of the hydrotreatment reactor to heat up the incoming materials in the stream 167. In other words, the heat exchange coil 235 plays the dual roles of providing heat in the initial section of the hydrotreatment reactor and removing heat in the later sections (downstream) of the hydrotreatment reactor.

The hydrotreatment reactor 210 can be placed vertically upright (Figure 2) or in any other directions relative to the ground. For example, the hydrotreatment reactor 210 can be placed vertically upside down with the inlet(s) at the lower position.

The hydrotreatment product stream 215 undergoes a step-wise cooling and condensation (250 and 260) to produce different product fractions 256 and 266 that are discharged via valves 255 and 265. The stream 257 is an intermediate between the steps. The cooling and condensation may be carried in any number of steps (two steps are shown in Figure 2 as an example). A back pressure regulator 278 is used to maintain the system pressure. While some of the stream 267 (in Figure 2) is vented (stream 279), the rest can be recycled back (not shown in Figure 2) to the

hydrotreatment reactor via the stream 220. Recycling can also be operated from any or all of streams 215, 257 or 267.

The heavier fraction 166 from the reactive distillation may also be hydrotreated in another hydrotreatment reactor. Similarly, the reactive distillation may have multiple steps of cooling and condensation (160, 170, 180 and 190 in Figure 1 as examples) to produce different fractions (166, 176, 186 and 196). All these different fractions can be hydrotreated together or individually in different hydrotreatment reactors. The present invention provides means for the production of these fractions and for these fractions to be hydrotreated in different hydrotreat reactors under conditions suitable for the hydrotreatment of each fraction. In some particular embodiments, any of the heavier fractions 166, 176, 186 and 196 can be thermally treated in another one or more reactors at higher temperatures to produce additional lighter products. The light products can then be hydrotreated.

Figure 3 shows a method of and system 201 for the reactive distillation of a bio-crude to produce lighter and heavier fractions, integrated with the hydrotreatment of the fractions. Similar to system 200, bio-oil from the pyrolysis of biomass is used as the bio-crude to illustrate the specific embodiments. Numerals in Figure 3 are the same as those in Figure 2 (method and system 200) and Figure 1 (method and system 100) and have the same functions as those in systems 200 and 100.

The main difference between system 201 and system 200 is that the lower section of the hydrotreatment reactor 210 also carries out the function of a separator. In other words, the separator 160 in Figure 2 is integrated with the hydrotreatment reactor 210 such that the separator 160 in Figure 2 becomes the lower section of the

hydrotreatment reactor 210 in Figure 3. The stream 220 enters the hydrotreatment reactor 210 from the bottom. The reacting fluid flows upward in the hydrotreatment reactor 210 in Figure 3. The stream 156 exiting the vessel 155 enters the bottom section of the reactor 210. The stream 156 mixes with the stream 220, which may cause further evaporation or condensation of some species in the stream 156. After mixing, stream 164 leaving the reactor 210 contains most of the heavier species in the stream 156 is discharged from a valve 165 as the stream 166 while the lighter species contained in the stream 156 flow upwards in the hydrotreatment reactor to be hydrotreated therein. The product stream 215 exits the hydrotreatment reactor 210 from its top and enters unit 250. The functions of all downstream units (250, 256, 260, 266 and 278) and streams (256, 257, 266, 267 and 279) are the same as those in system 200 in Figure 2.

For systems 200 and 201 , there can be more than one hydrotreatment reactors in series. In one embodiment, each hydrotreatment reactor can have a bio-crude fraction feedstock (e.g. stream 167 in Figure 2 or stream 156 in Figure 3) produced from its own reactive distillation system using the bio-crude (bio-oil 101), which is the same as that defined by numerals from 101 to 167 (Figure 2) or from 101 to 156 (Figure 3). For the second hydrotreatment reactor or each of further downstream hydrotreatment reactor, the hydrogenation agent stream (e.g. 220) can comprise the fresh

hydrogenation agent and the product stream (e.g. 215) from the preceding hydrotreatment reactor.

Figure 4 shows a method of and system 300 for the reactive distillation of a bio-crude to produce lighter and heavier fractions, integrated with the reforming of the fractions to produce a synthesis gas product. The synthesis gas can also be used to produce hydrogen. Bio-oil from the pyrolysis of biomass is used as the bio-crude to illustrate the specific embodiments.

Many numerals in Figure 4 (method and system 300) are the same as those in Figure 1 (method and system 100) and have the same functions as those in method and system 100.

The lighter fraction 167 produced from the reactive distillation of bio-oil 101 passes through a pressure-regulating device 310 to change its pressure (to become a stream 305) to a level close to the intended operation pressure for a reformer 320. In one embodiment, the reformer 320 is operated at a pressure close to the atmospheric (ambient) pressure.

The stream 305 is mixed with a stream 330 containing reforming agents. In one embodiment, the reforming agents are a mixture of air and steam to achieve autothermal reforming operation. In a further embodiment, the air is replaced with oxygen or oxygen-enriched air to produce a synthesis gas containing no or less nitrogen. In another embodiment, the reforming agents are steam if a separate heat source is available to supply heat to the reformer 320 (not shown in Figure 4). CO2 and H2 can also be part of the reforming agent mixture in all cases. The mixing of streams 305 and 330 can be carried out just before they enter the reformer 320, at the entrance to the reformer 320 or inside the reformer 320.

The reforming reactions in the reformer 320 are chosen to convert as much the organic components in the stream 305 (167) to synthesis gas (mainly CO, H ₂ and C0 ₂ ) as possible. If the synthesis gas is to be used subsequently for power generation, it would be beneficial to increase the concentrations of light hydrocarbons such as CH4, C ₂ H ₆ and C ₃ H ₈ in the synthesis gas.

The reformer 320 may contain various catalysts.

The reforming product stream 335 may contain a variety of undesirable components such as tarry material, inorganic vapour (e.g. K volatilised from biomass during pyrolysis and present in the bio-oil 101) and NO _x /SO _x and their precursors. An important advantage of the present invention is that inorganic vapour is minimised in stream 167. It is often required or beneficial to remove these organic and inorganic impurities from the reforming product gas 335. Many different hot gas cleaning technologies can be used for this purpose although the technology disclosed in PCT/AU2014/001 135 is particularly advantageous for this purpose. In one

embodiment, the hot gas cleaning is carried out in two stages. In the first stage (340), the product gas stream 335 passes through a bed of char or char-supported catalyst with the product gas flowing in a direction perpendicular to the flow direction of char catalyst (not shown). The key function of the first stage is to reform tarry materials, to destruct such impurities as NH _3, HCN and H ₂ S and to remove any large particulates (if any). The stream 345 exiting the first stage enters the second stage (350) that contains porous media. The key function of the second stage is to cool down the product stream 345, to recover the thermal energy and to condense the remaining organic and inorganic impurities on the porous media. The porous media can comprise char or char-containing adsorbent. The cooling is carried out using a heat exchange medium in a heat exchanger that also houses the porous media (see PCT/AU2014/001135). A clean product gas is produced as stream 355.

The method and system 300 of the present invention also provides the option to reform or burn the heavier fraction 164 from the reactive distillation of bio-crude. The stream 164 passes through the pressure-regulating device/valve 165 to form a stream 166 that is at a pressure level close to the required operation pressure of a reformer 360. The stream 166 mixes with a mixture of reforming agents 365 either before entering the reformer 360, at the entrance to the reformer 360 or after being inside the reformer 360. The stream 365 can contain a high concentration of oxygen and other reforming agents such as steam and C0 ₂ . In a particular embodiment, the stream 365 is mainly air or oxygen wherein the heavier fraction 164 (166) is burned. The reforming product gas 367 leaving the reformer 360 can either enter the reformer 320 or enter the hot gas cleaning system (340). The ash 366 is discharged.

One of the important advantages of the reactive distillation is that the bio-crude 101 is separated into the lighter fraction 167 and the heavier fraction 164, which have very different reforming activities and can be reformed under very different conditions. In one particular embodiment, the heavier fraction 164 is simply burned with high concentration of oxygen in the reformer 360. The thermal energy embedded in the product gas 367 is used to meet the head demand of the endothermic reactions in the reformer 320. The lighter and more reactive fraction 167 can thus be reformed with less oxygen and thus higher efficiency in the reformer 320. Burning the heavier and refractory fraction (164) represents the quickest and most efficient way to reform the bio-oil 101.

Another important advantage is that the lighter fraction 167 with reduced coking propensity can be reformed catalytically in the reformer 320 with a longer catalyst life while the heavier fraction with higher propensity to form coke can be burned or reformed without a catalyst.

In an embodiment, one or more of the reforming reactors are operated as combustion reactors. In a further embodiment, the reformed products from any or all of the reforming or combustion reactors further undergo cleaning using char or char- supported catalysts, for example using the above-mentioned two-stage hot cleaning gas cleaning process (340 and 350). In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word“comprise” or variations such as“comprises” or“comprising” is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.