NL2004898C2

NL2004898C2 - Pyrolysis of lignin.

Info

Publication number: NL2004898C2
Application number: NL2004898A
Authority: NL
Inventors: Ruud Wilberink; Ron Laan; Paulus Johannes Wild
Original assignee: Stichting Energie
Priority date: 2010-06-16
Filing date: 2010-06-16
Publication date: 2011-12-20
Also published as: WO2011159154A1

Abstract

The invention provides a process for the pyrolysis of lignin. The lignin- containing material is intimately mixed with a phyllosilicate clay and optionally pelletised. The pelletised starting material is fed into a pyrolysis reactor and pyrolysed to provide a pelletised carbonaceous product and a bio-oil containing lignin monomers.

Description

Pyrolysis of lignin

Field of the invention

The invention relates to the thermolysis of biomass, such as lignin. The invention 5 further relates to the product obtained thereby, as well as to the use of such product.

Background of the invention

The thermal treatment of biomass may be used to generate valuable materials such as char, activated charcoal, bio-oil, combustible gasses, etc.

10 W02008147711, for instance, describes a system and method for preparing a pelletized carbon black product. The system includes a source of a carbon black product from a pyrolysis process. A mixer is in communication with the source of the carbon black product. A binder oil storage tank is in fluid communication with the mixer. The binder oil storage tank is configured to inject a desired amount of a binder 15 oil into the mixer to form the pelletized carbon black product.

WO2009138757 describes a biomass pyrolysis process in which biomass feedstock is mixed with a heat carrier. The heat carrier at least partly comprises char. The ratio by weight of biomass to char is in the range 1:1 to 1:20. The process may be carried out by in a screw/auger pyrolysis reactor in which the solid feedstock 20 components are conveyed along the reactor by a first screw. A second screw conveys at least a portion of the solid products of the biomass pyrolysis back to a heat transfer medium input port. The heat transfer medium includes char from the biomass pyrolysis.

W02010011675 describes a method for producing activated charcoal from lignocellulose-containing material residual solids, wherein the method comprises: i) 25 pre-treating lignocellulose-containing material; ii) hydrolyzing pre-treated lignocellulose-containing material; iii) recovering residual solids; iv) producing activated charcoal from the residual solids. The activated charcoal may be produced from charcoal made by carbonization or pyrolysis.

WO 8800935 describes a process for the pyrolysis of biomass to produce a high 30 yield of a liquid bio-oil in a reactor that is capable of rapid heat exchange and short gas residence times. The pyrolysis liquid typically contains 10 % - 30 % (wt%) water and can be further processed to divide it into a water-rich fraction and a water-poor fraction. These fractions can be used as feed stocks from which valuable chemicals can be 2 extracted. The pyrolysis process also can be used to produce a pyrolysis liquid that is suitable as a fuel-oil. Finally, in another embodiment, the process can be used to produce a pyrolysis liquid that is suitable for use as liquid smoke which can be used to flavour food, particularly meat.

5 W0200006671 describes a method and device for forming synthesis gas from biomass. In a pyrolysis zone, the biomass is converted into a solid carbonization product (char) and into gaseous pyrolysis products. The gaseous pyrolysis products are burnt in a burner zone and supply the heat for the endothermic pyrolysis process and for an endothermic gasification process for forming synthesis gas. The carbonization 10 products are fed to the gasification zone, in order to be converted, for example by means of steam, into 1¾ and CO. The fact that the gaseous pyrolysis products and the off-gases from the combustion zone are separate from the gasification zone results in a product gas with a high calorific value which is virtually free of nitrogen. The fact that the solid carbonization products from the pyrolysis process are fed to the gasifier 15 results in a very pure product gas which is free of contaminants which are usually formed when gaseous pyrolysis products are converted into synthesis gas. The device according to W0200006671 can therefore be operated without using complex purification installations.

20 Summary of the invention A disadvantage of prior art solutions may be that some types of biomass, such as lignin, are not easily thermally treated, such as for instance by pyrolysis. Hence, it is an aspect of the invention to provide an alternative process, which preferably obviates (prior art) problems as mentioned herein. Especially, it is an object to provide a process 25 wherein lignin can be used as starting material for the production of an upgraded lignin material, without problems of clogging of apparatus. It is also an aspect of the invention to provide a process for the production of bio-char and bio-oil from a lignin, preferably also without problems of clogging of apparatus.

In an embodiment, the invention provides a process for the thermolysis of 30 biomass comprising: a. pretreating a mixture comprising the biomass and a clay, wherein the pretreatment comprises pelletizing the mixture, to provide a pelletized starting material; 3 b. introducing the pelletized starting material obtained at a) to a reactor; and c. thermolising the pelletized starting material in the reactor, especially to provide a pelletized end product and a bio-oil.

With the new and claimed concept for an efficient thermochemical conversion of 5 lignin into value-added products up to 80 wt.% of the dry lignin can be transformed into useful products such as bio-char and phenolic bio-oil. The phenolic-oil is an interesting feedstock for e.g. bio-bitumen, phenol substitutes in wood-resins and for several high-value phenolic compounds like guaiacols, syringols and alkylated phenols for pharmaceutical, food, and/or transportation fuel applications.

10 Further, continuous pyrolysis of lignin using conventional screw feeders may now be possible. Further, advantageously, the shape and composition of the pelletized end product may be tuneable, which allows a tuning to the desired later application of the pelletized end product. The amount of carbon that originates from the pyrolysis of the lignin can be adjusted by the ratio lignin: clay in the pelletised feedstock material. For 15 soil improvement, the pelletized end product (‘biochar’) might contain more or less carbon, depending on the soil characteristics. In case of a sandy soil, it might be preferable to have a relative high content of clay in the pelletized end product to enhance the water retention in the soil. On the other hand, the application of the pelletized end product as gas- and/or liquid filtration material for organic substances 20 probably requires a higher amount of pyrolytic carbon because of its hydrophobic (apolar) character when compared to the clay constituent. Here, the clay may act as a porous support that gets coated with lignin-derived carbon during the pyrolysis process.

After the thermolysis, a pelletized end product is obtained. This product may herein also be indicated as “pelletized carbonaceous product”. The term “pelletized end-25 product” is used to distinguish from the pelletized starting material. The term does not exclude a later use or processing of the “pelletized end-product”, but refers to the product obtained by the process of the invention.

Hence, the invention also provides a pelletized end product obtainable by the process of the invention. Especially, a pelletized carbonaceous product is provided 30 comprising pellets having mean dimensions in the range of 0.25-10 mm, such as 0.25-5 mm, like 0.5-5 mm, especially 1-3 mm, wherein the pellets comprise thermolised biomass, and wherein the pellets preferably comprise carbon in an amount of 5-60 wt.%, oxides of magnesium and silicon preferably in an amount of 30-95 wt.%, and 0- 4 10 wt.% other materials, e.g. aluminium, alkali metals like sodium and potassium, alkaline earth metals like calcium and transition metals like iron, relative to the total weight of the pellets and on dry weight basis. As mentioned above, the thermolised biomass especially comprises thermolised cellulosic material, even more especially, the 5 thermolised biomass comprises thermolised lignin. Preferably at least 50 wt.%, even more preferably at least 80 wt.% of the pelletized end product particles has a particle size in the indicated ranges, respectively. The term “dimensions” is used to refer to length, width and diameter. As will be clear to the person skilled in the art, diameter may especially be applicable for particles having a spherically or elliptically cross-10 section. The term “mean dimension” refers to an average over a plurality of particles.

The pelletized carbonaceous material (pelletized end product) can be used as a soil improver, for instance to enable or enhance the growth of feed and food crops on barren soils. The pelletized carbonaceous product may also be used as precursor for activated carbon, for instance for the production of gas and liquid filtration media. The 15 pelletized carbonaceous material may also be used as a (low-cost) lignin-based cracking catalyst, for instance in pyrolysis processes like the one that is described in this patent. Further, the pelletized carbonaceous product may also be used as a CO2-neutral fuel, for instance in waste incinerators or as internal fuel for lignin-pyrolysis processes, whereby the combustion of the carbonaceous fuel pellets ensures that the 20 endothermic pyrolysis process is self-sufficient with respect to its heat demand. The bio-oil may also be used in all kind of useful processes (see also above).

Brief description of the drawings

Embodiments of the invention will now be described, by way of example only, 25 with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

Figure 1 schematically depicts the process of the invention. References A1-A4 indicate the components of the mixture for the pre-treatment, comprising lignin (Al), clay (A2), water (A3) and optional one or more other components (A4), like catalysts 30 for cracking, demethoxylation, decarbonylation, decarboxylation, hydrolysis, and/or dehydration, etc. Examples are commercial FCC catalysts, ZSM-5 catalysts, supported transition metals (e.g. Ni), and natural tar cracking catalysts like dolomite, olivine and iron-ore.

5

The mixture is then subjected to a pre-treatment (B), which at least involves a pelletization to provide a pelletized starting material. Thereafter, the pelletized starting material is subject to thermolysis (C) to provide the pelletized end product. The pelletized end product may be used in all kinds of applications (D).

5 Figure 2 schematically depicts an arrangement 1 of apparatus that may be used for the process of the invention. Reference 2, 3 and 4 schematically depict the feeds for lignin, clay and water respectively. Optionally, also other components may be added (not indicated in the drawing). Reference 10 indicates a mixer, wherein the starting materials are mixed into a paste. The paste may be extruded in an extruder, reference 10 20. This may for instance be followed by strand cutting and rotary drying, indicated with reference 30. Then, the pelletized starting material thus obtained is fed to a reactor. In an embodiment, this is done via a two stage process, via a metered pellet feeding screw 40 and a (water) cooled reactor feeding screw 50. Between the feeding screw 40 and the rotary drying, a feed downer pipe 31 may be arranged, but other 15 constructions may also be possible. Between the metered pellet feeding screw 40 and the reactor feeding screw 50 a feed bunker 41 may be arranged, but other constructions may also be possible.

Preferably, the pelletized starting material is provided to a lower part of the reactor. The reactor is indicated with reference 60. Here, schematically, a pyrolysis 20 reactor (fluid-bed based) is depicted. Reference 61 indicates the fluid bed, and reference 62 indicates an char overflow pipe, leading to a char bin 63. Fluidisation gas 64 may amongst others be introduced at the bottom 65 of the reactor 60. Particulate product may for instance be recovered via a cyclone 70. An ash bin 71 may be used to collect solid material that is entrained in the fluidization gas, e.g. fine sand, clay and char 25 particles. Via a hot gas particle filter 80, the particulate product, here indicate with reference 90, may be obtained. Reference 100 indicates a compressor.

Figure 3 shows the Phenolic yields from the pyrolysis of promoted Alcell lignin (A) at 400°C; X = sepiolite, Y = attapulgite, Z = bentonite, MgO = magnesium oxide, Si02 = silica (sand). The numbers between brackets indicate the weight ration of the Alcell 30 lignin and the promotor. The y-axis in this figure indicates the product yield in wt.% d.b.; MP indicates monomeric phenols, OP, indicates oligomeric phenols and TPF indicates total phenolic fraction 6

Description of preferred embodiments

At present, utilization of lignin is growing due to an increasing interest in renewable raw materials. Large amounts of lignin and lignin containing residues originate from the pulp- and paper industry. The expected growth of the production 5 capacity of second generation bio-fuels from ligno-cellulosic biomass will lead to another source of lignin and lignin containing residues.

Despite its large potential as a significant and valuable petrochemical substitution option for fuel, performance products (polymers) and individual low molecular weight chemicals, the main practised option to date is the use as a low-cost solid fuel for 10 generating heat. To exploit the potential of lignin as a renewable feedstock for (transportation) fuels, chemicals and performance products, new conversion technologies are needed.

Economic and technological considerations still preclude a large-scale mass production of low molecular weight chemicals from lignin in competition with 15 petrochemicals. This is inherent to the specific nature of the complex and stable lignin polymer that makes it difficult to convert it into valuable monomeric chemicals.

Conventional fluidised-bed pyrolysis to convert lignin into valuable products (like biochar and bio oil) may be problematic due to the physico-chemical characteristics of lignin as a heterogeneous powder-like material that is sticky, 20 thermoplastic but simultaneously thermally stable. The valorisation of lignin by pyrolysis processes may especially be hampered by feeding difficulties and by the recalcitrant nature of the lignin polymer towards thermal degradation.

Continuous pyrolysis of lignin using conventional screw feeders may be very difficult because the easily melting lignin powder will block the feeding tube in no 25 time. Other feeding methods, like fast pneumatic injection of the fine lignin powder, may be problematic too because of the stickiness of the fine lignin powder and its tendency to become electrostatically charged. When the fine lignin powder eventually enters the reactor, sudden melting and blowing-up of the reacting particles may cause agglomeration and subsequent defluidisation of the hot sand bed in the reactor. As a 30 consequence the thermal degradation of the lignin may rapidly shift to charring, causing a much decreased yield of valuable organics.

The use of the “promoted” lignin, as suggested herein, in a new and innovative pyrolysis concept offers an unexpected solution for the abovementioned problems.

7

Hence, it is an aspect of the invention to provide an alternative process, which preferably further at least partly obviates one or more of above-described drawbacks.

The products of thermal treatment of state of the art process may be applied in for agricultural applications of construction applications (for instance solidification of 5 dykes, etc.). However, the composition of such products of thermal treatment of state of the art process may not easily be varied. Hence, it is an further aspect of the invention to provide a process, wherein the composition of the product obtained thereby, is preferably variable.

With the new and claimed concept for an efficient thermochemical conversion of 10 lignin into value-added products up to 80 wt.% (weight percentage) of the dry lignin can be transformed into useful products such as bio-char (30-50 wt.%) and phenolic bio-oil (30-50 wt.%). The phenolic-oil is an interesting feedstock for e.g. bio-bitumen, phenol substitutes in wood-resins and for several high-value phenolic compounds like guaiacols, syringols and alkylated phenols for pharmaceutical, food, and/or 15 transportation fuel applications.

The pyrolysis concept of the invention may include a combination of pretreatment, feeding and pyrolysis conditions to convert for instance lignin into valuable products. The pre-treatment is the main technical innovation and involves a procedure to pelletize the biomass material such as lignin, with a specific low-cost additive that 20 improves its feeding and pyrolysis behaviour. Feeding of the (lignin-additive) pellets into the reactor may be accomplished by using an adapted continuous screw feeder. A combination of feed-rate, reactor temperature and fluidisation gas velocity may ensure an efficient pyrolysis of the pelletized starting material in such a way that a maximum yield of valuable products is obtained.

25 The application of the additive, in the form of lignin clay, may surprisingly prevent defluidisation of the reactor sand bed and enables an efficient separation of char, sand and condensable pyrolysis products.

In a specific embodiment, the invention provides a process for the thermolysis of biomass comprising: 30 a. pretreating a mixture comprising the biomass and a clay, wherein the pre treatment comprises pelletizing the mixture, to provide a pelletized starting material; b. introducing the pelletized starting material obtained at a) to a reactor; and 8 c. thermolising the pelletized starting material in the reactor (especially to provide a pelletized end product and a bio-oil).

With the new and claimed concept for an efficient thermochemical conversion of lignin into value-added products up to 80 wt.% of the dry lignin can be transformed 5 into useful products such as bio-char and phenolic bio-oil. Further, continuous pyrolysis of lignin using conventional screw feeders may now be possible. Further, advantageously, the composition of the pelletized end product may be tuneable, which allows a tuning to the desired later application of the pelletized end product. The amount of carbon that originates from the pyrolysis of the lignin can be adjusted by the 10 ratio ligninxlay in the pelletised feedstock material. For soil improvement, the pelletized end product (‘biochar’) should contain more or less carbon, depending on the soil characteristics. In case of a sandy soil, it might be preferable to have a relative high content of clay in the pelletized end product to enhance the water retention in the soil. On the other hand, the application of the pelletized end product as gas- and/or liquid 15 filtration material for organic substances probably requires a higher amount of pyrolytic carbon because of its hydrophobic (apolar) character when compared to the clay constituent. Here, the clay acts as a porous support that gets coated with lignin-derived carbon during the pyrolysis process.

Preferably, the thermolising of the pelletized starting material in the reactor 20 comprises pyrolysing the pelletized starting material. Pyrolysis is the chemical decomposition of condensed substances by heating that occurs spontaneously at high enough temperatures. Pyrolysis is a special case of thermolysis, and is most commonly used for organic materials, being then one of the processes involved in charring. This chemical process is heavily used in the chemical industry, for example, to produce 25 charcoal, activated carbon, methanol and other chemicals from wood, to convert ethylene dichloride into vinyl chloride to make PYC, to produce coke from coal, to convert biomass into syngas, to turn waste into safely disposable substances, and for transforming medium-weight hydrocarbons from oil into lighter ones like gasoline. These specialized uses of pyrolysis may be called various names, such as dry 30 distillation, destructive distillation, or cracking. Herein, pyrolysis especially refers to the process of heating materials in the absence of introduction of oxygen or air at a temperature in the range of about 300-700 °C, like 300-600 °C, such as 350-550 °C.

9

Preferably, the biomass comprises cellulosic material, even more preferably, the biomass comprises lignin. For instance, in an embodiment the biomass comprises technical lignin (i.e. especially a material that contains typically > 90 wt% pure lignin). In a further embodiment, the biomass comprises a lignin from the pulp- and paper 5 industry, e.g. in the form of black liquor derived lignin (e.g. from organosolv, soda, sulfite or Kraft pulping), or a lignin from the production of second generation bio fuels (like bio-ethanol). The use of specific clays to prepare an aqueous lignin-clay slurry is especially suitable for relatively pure lignins (> 80 wt.% lignin (dry base)) that are prepared from biomass such as wood, straw and grass by techniques such as 10 water/ethanol and acid organosolv delignification and soda-pulping. Examples are Alcell organosolv lignin (prepared from water/ethanol fractionation of a mixture of hardwoods) and Granit soda-pulping lignin (prepared from a mixture of wheat straw and Sarkanda grass). The physical appearance of these lignins is a light (Granit) to dark brown (Alcell) powder (particle size <0.1 mm) that easily melts at low temperatures (< 15 200°C). Both lignins are virtually immiscible with water. In general, technical lignins from e.g. organosolv fractionation with water/ethanol or from soda-pulping are not easily miscible with water due to their hydrophobic character.

The term “lignin” may refer to a natural lignin, but may also refer to chemical derivatives thereof. In one embodiment, the term “lignin” may also refer to “lignin 20 sulfonate”. In another embodiment, ammoniumlignosulfonate is used as lignin compound. Lignin compounds are found in cell walls as a cement layer between cellulose strands. They are copolymers, i.e. macromolecules of which the monomers are of a different nature. Three phenyl-propane (C6-C3) derivates are considered as being monomers of lignin: e.g. coneferyl alcohol, sinapyl alcohol and coumaryl or p-25 hydroxy cinnamyl alcohol. They are coupled together via C-C bonds of the propane chains and via ether bonds between alcoholic groups. In an embodiment, the lignin compound used in the invention comprises one or more of lignin and lignosulfonate. Lignins can be obtained from wood, like e.g. softwood (conifers) or hardwood. The molecular weight varies between about 5,000 and 10,000.

30 It surprisingly appears that whereas lignin alone or in combination with water, is not easily processable, clay as additive provides a mixture that is relatively easily pelletizable and later thermolisable in a reactor, without substantially clogging of apparatus. For instance, mixing the lignin powder with some specific powdered 10 (particle size <0.1 mm) clays such as sepiolite, attapulgite and/or bentonite greatly enhances the miscibility with water and enables the preparation of an homogeneous aqueous lignin-clay slurry. The thickness of the slurry can be adjusted by the amount of water.

5 The lignin-clay slurry can easily be pelletised by well-known techniques such as extrusion. The homogeneity of the lignin-clay slurry may ensure an even distribution of clay and lignin in the resulting pellets or extrudates. To increase the mechanical strength of the pellets, a mild temperature treatment (preferably < 150°C in air or vacuum) can be applied to sinter the lignin-clay mixture. It is assumed that the clay acts 10 as a sort of binder for the lignin. Other clays that possess a high level of porosity and water uptake capacity might be suitable as well.

The clay preferably comprises one or more clays selected from the group consisting of a hormite clay (such as a sepiolite clay), a bentonite clay, an attapulgite clay, and a montmorrilonite clay. Especially preferred are bentonite and/or sepiolite. In an 15 embodiment, the clay comprises hydrotalcite clay. The term “clay” may in an embodiment refer to a combination of clays, such as a combination of bentonite and sepiolite.

The clay may especially be clay from the hormite group. Clays from the hormite group are, for example, palygorskite, attapulgite, sepiolite and paramontmorillonite. 20 Preferably, the clay used is sepiolite. The clays from the hormite group are known from the literature. Sepiolite and palygorskite are, for example, described by Galan (Clay Minerals (1996), 31, 443-453). Sepiolite is widely found in Spain.

Alternatively, the clay may also be from the bentonite group. Bentonite is an absorbent aluminium phyllosilicate, generally impure clay consisting mostly of 25 montmorillonite. There are different types of bentonites and their names depend on the dominant elements, such as potassium (K), sodium (Na), calcium (Ca), and aluminium (Al). Bentonite usually forms from weathering of volcanic ash, most often in the presence of water. However, the term bentonite, as well as a similar clay called tonstein, have been used for clay beds of uncertain origin. For industrial purposes, two 30 main classes of bentonite exist: sodium and calcium bentonite.

In the pre-treatment, the lignin and the clay are mixed, in general together with water, to provide a paste or slurry, preferably a paste. There from, pellets are created.

11

This may be done with methods known in the art. Dependent upon the method chosen, the pre-treatment may include a heating before and/or after the pelletization.

The biomass (typically containing 0-10 wt.% of moisture) and the clay (typically containing 0-10 wt.% of moisture) are preferably mixed in a weight ratio of 90:10 to 5 10:90, preferably in a weight ratio of 80:20 to 20:80, based on the dry weight of the materials. Further, the amount of water of the mixture (before pelletisation and a heating) is preferably in the range of about 30-70 wt.%, preferably in the range 40 - 60 wt% relative to the total weight of the mixture of lignin, clay and water (and optional other components).

10 In a specific embodiment, the pre-treatment comprises (al) providing a paste of biomass, clay and water (and optional other components), (a2) extruding the paste, (a3) providing particulate material, and (a4) drying the particulate material to provide the pelletized starting material. Instead of extruding using an extruder, the paste may also be pressed through a sieve with appropriate meshes.

15 The pre-treatment provides a particulate material (“pelletized starting material”), that may be used for the thermolysis, especially pyrolysis. The pelletized starting material preferably comprises pellets having mean dimensions in the range of 0.25-10 mm, preferably 1-3 mm. Especially, at least 70 wt.%, more preferably at least 80 wt.%, even more preferably, at least 90 wt.% of the pelletized material consists of pellets 20 having mean dimensions in the range of 0.25-10 mm or 1-3 mm, respectively. Optionally, too large and/or too small particles may be separated from the pelletized material, for instance by sieving or using a cyclone separator, or other methods known in the art.

The pelletized starting material may then be used in a thermal process, to provide 25 carbonaceous material, such as charcoal (herein also indicated as “bio char” since it originates from biological material) and bio oil. The thermal process is preferably applied in a fluidized bed reactor.

Hence, the invention also provides a process (for the thermolysis as described herein), wherein the reactor is a fluidized bed reactor. The pelletized starting material is 30 introduced in the fluidized bed reactor and fluidized. In this fluidized “state” the lignin is thermo Used (especially pyrolised), by which a pelletized end product is obtained and by which bio oil is obtained. The pelletized starting material seems to be surprisingly stable, leading to a pelletized end product having substantially the same dimensions as 12 the pelletized starting material, but now substantially consisting of thermolised lignin and clay. The latter may not substantially be effected by the thermolysis, whereas the former may be transformed in char and bio-oils (and gasses). The char particles and the oils may be retrieved from the reactor. The oil originates from the pyrolysing lignin in 5 the form of condensable organic vapours, water and aerosols that contain water and organics. This product mixture may be collected downstream the reactor by means of appropriate collecting equipment, consisting of cooled condensers for the condensable vapours and an electrostatic precipitator for the aerosols. Hence, the invention especially provides a process for the thermolysis of biomass as described above, to 10 provide bio char and bio oil from a lignin. In an embodiment, the process of the invention may be a continuous process (for the production of the pelletized end product and/or bio oil).

Preferably, thermolysis is performed at a temperature in the range of 300-700 °C, especially in the range of 350-450 °C.

15 After the thermolysis, a pelletized end product is provided, Hence, the invention also provides a pelletized end product obtainable by the process of the invention. Especially, a pelletized carbonaceous product comprising pellets having mean dimensions in the range of 0.25-10 mm (or other dimension ranges as indicated herein), wherein the pellets comprise thermolised biomass, and wherein the pellets comprise 20 carbon in an amount of 5-60 wt.%, oxides of magnesium and silicon in an amount of 30-95 wt.%, and 0-10 wt.% other materials, relative to the total weight of the pellets and on dry weight basis. As mentioned above, the thermolised biomass especially comprises thermolised cellulosic material, even more especially, the thermolised biomass comprises thermolised lignin. Likewise, the invention also provides a bio oil 25 obtainable by the process of the invention. As will be clear to the person skilled in the art, the term bio oil herein may also refer to a mixture of oils (obtainable by the process).

The term “substantially” herein will be understood by the person skilled in the art. The term “substantially” may also include embodiments with “entirely”, 30 “completely”, “all”, etc. Hence, in embodiments the adjective substantially may also be removed. Where applicable, the term “substantially” may also relate to 90% or higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or 13 higher, including 100%. The term “comprise” includes also embodiments wherein the term “comprises” means “consists of’.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for 5 describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

The devices herein are amongst others described during operation. As will be 10 clear to the person skilled in the art, the invention is not limited to methods (or processes) of operation or devices in operation.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In 15 the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb "to comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising 20 several distinct elements, and by means of a suitably programmed computer. In the device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

25 Specific embodiment are indicated below. Only for the sake of understanding, the embodiments are numbered: 1. A process embodiment for the thermolysis of biomass comprising: a. pretreating a mixture comprising the biomass, wherein the biomass comprises lignin, and a clay, wherein the pre-treatment comprises pelletizing the 30 mixture, to provide a pelletized starting material; b. introducing the pelletized starting material obtained at a) to a reactor; and c. pyrolysing the pelletized starting material in the reactor.

14 2. The process embodiment according to the process embodiment 1, wherein the biomass comprises technical lignin.

3. The process embodiment according to any one of the preceding process embodiments, wherein the biomass comprises a lignin from the pulp- and paper 5 industry, e.g. in the form of black liquor-derived lignin or a lignin from the production of second generation bio fuels.

4. The process embodiment according to any one of the preceding process embodiments, wherein the clay comprises a hormite clay.

5. The process embodiment according to any one of the preceding process 10 embodiments, wherein the clay comprises a bentonite clay.

6. The process embodiment according to any one of the preceding process embodiments, wherein the clay comprises a sepiolite clay.

7. The process embodiment according to any one of the preceding process embodiments, wherein the clay comprises an attapulgite clay.

15 8. The process embodiment according to any one of the preceding process embodiments, wherein the clay comprises a montmorrilonite clay.

9. The process embodiment according to any one of the preceding process embodiments, wherein the biomass and the clay are mixed in a weight ratio of 90:10 to 10:90, based on the dry weight of the materials.

20 10. The process embodiment according to any one of the preceding process embodiments, wherein the pre-treatment comprises (al) providing a paste of biomass, clay and water, (a2) extruding the paste, (a3) providing particulate material, and (a4) drying the particulate material to provide the pelletized starting material.

11. The process embodiment according to any one of the preceding process 25 embodiments, wherein the pelletized starting material comprises pellets having mean dimensions in the range of 0.25-10 mm.

12. The process embodiment according to any one of the preceding process embodiments, wherein the reactor is a fluidized bed reactor 13. The process embodiment according to any one of the preceding process 30 embodiments, wherein thermolysis is performed at a temperature in the range of 300- 700 °C, especially in the range of 350-550 °C.

14. A pelletized end product embodiment obtainable by the process embodiments according to any one of the preceding process embodiments.

15 15. A pelletized carbonaceous product embodiment comprising pellets having mean dimensions in the range of 0.25-10 mm, wherein the pellets comprise thermolised lignin, and wherein the pellets comprise carbon in an amount of 5-60 wt.%, oxides of magnesium and silicon in an amount of 30-95 wt.%, and 0-10 wt.% other materials, 5 relative to the total weight of the pellets and on dry weight basis.

16. Use embodiment of the pelletized carbonaceous product according to any one of the product embodiments 14-15, as a soil improver.

17. Use embodiment of the pelletized carbonaceous product according to any one of the product embodiments 14-15, as precursor for activated carbon.

10 18. Use embodiment of the pelletized carbonaceous product according to any one of the product embodiment 14-15, as a low-cost lignin-based cracking catalyst.

19. Use embodiment of the pelletized carbonaceous product according to any one of product embodiments 14-15, as a C02-neutral fuel.

20. Use embodiment of the process embodiment according to any one of the 15 process embodiments 1-13, to provide bio-char and bio-oil from a lignin.

Experimental

Pelletizing experiments with lignin, with lignin + sand

Pure lignin pellets can be prepared by (partially) dissolving the lignin in an 20 organic solvent such as ethanol, methanol or acetone and subsequent evaporation of the solvent. The resulting cake can be crushed and sieved into an appropriate size fraction. However, the mechanical strength is poor, a lot of material is lost due to the sieving procedure and it is not certain if chemical changes have occurred due to the solvent treatment. Alcell lignin also can be pelletised by evaporation and subsequent crushing 25 or extruding an aqueous slurry that is prepared by vigorously shaking the lignin powder with water. The resulting particles are weak and easily fall apart. The mechanical strength of these particles can be increased somewhat by a fusion treatment below 200°C and subsequent solidifying. This procedure also can be applied to the pure lignin powder.

30 16 (pelletizing) experiment with silica sand

Lignin - sand particles were prepared by crushing and sieving of a lignin-sand cake that was made by fusion at 170°C and subsequent solidifying of a 1:1 (wt/wt) mixture of Alcell lignin powder with silica sand (particle size -0.25 mm).

5 (pelletizing) experiments with natural MgO mineral

Natural magnesium oxide mineral was mixed with Alcell lignin and water and converted into a slurry. It proved to be extremely difficult to extrude this slurry due to phase separation during the extrusion process. However, the slurry could be dried at 200°C under air without melting.

10

Sample preparation by pelletizing

Five batches of 1 - 3 mm Alcell organosolv lignin particles were prepared according to the following procedures: 1. Slurrying the lignin with water under vigorous agitation, applying the resulting

15 paste on a perforated plate (2 mm cylindrical holes), drying and sintering at 140°C

under air, pressing / sieving out particles 1-3 mm, this sample is coded Alcell-Pure.

2. Mixing the lignin with an equal amount (weight) of 0.25 mm silica sand, melting it at 170°C in an oven under air for approx. 1 hr, cooling down / solidifying overnight 20 till room temperature, crushing the resulting lignin - sand cake, sieving out particles of 1 - 3 mm, this sample is coded Alcell-Sand.

3. Slurrying equal amounts of lignin and sepiolite clay with water, extruding the resulting paste into 3-5 mm (length) x 3 mm (diameter) extrudates, drying/sintering at 140°C, this sample is coded Alcell-Sep.

25 4. Slurrying equal amounts of lignin and attapulgite clay with water, extruding the resulting paste into 3-5 mm (length) x 3 mm (diameter) extrudates, drying/sintering at 140°C, this sample is coded Alcell-Atta.

5. Slurrying equal amounts of lignin and bentonite clay with water, extruding the resulting paste into 3-5 mm (length) x 3 mm (diameter) extrudates, drying/sintering 30 at 140°C, this sample is coded Alcell-Ben.

17

To study the effect of reactor temperature, load and type of additive and type of lignin on the pyrolysis behaviour, another nine batches of 1-3 mm lignin-additive particles were prepared according to the following procedure: 1. Slurrying Alcell lignin and sepiolite clay in a weight ratio of 80:20 with water, 5 extruding the resulting paste into 3-5 mm (length) x 2-3 mm (diameter) extrudates, drying/sintering at 140°C, this sample is coded AX, 2. Slurrying Alcell lignin and attapulgite clay in a weight ratio of 80:20 with water, extruding the resulting paste into 3-5 mm (length) x 2-3 mm (diameter) extrudates, drying/sintering at 140°C, this sample is coded AY.

10 3. Slurrying Alcell lignin and bentonite clay in a weight ratio of 80:20 with water, extruding the resulting paste into 3-5 mm (length) x 2-3 mm (diameter) extrudates, drying/sintering at 140°C, this sample is coded AZ.

4. Slurrying the Alcell lignin with natural magnesium oxide mineral in a weight ratio of 80:20 with water, extruding the resulting paste into ill-defined extrudates that 15 were sintered at 140-170°C. The resulting extrudates could not be handled without falling apart, so it was decided to crush the soft extrudates and use the Alcell-lignin powder instead., this sample is coded AMI, 5. Slurrying the Alcell lignin with natural magnesium oxide mineral in a weight ratio of 50:50 with water, preparing sintered lignin-MgO powder as described under 4.

20 this sample is coded AM2, 6. Mixing the Alcell lignin with an equal amount (weight) of 0.25 mm silica sand, melting it at 170°C in an oven under air for approx. 1 hr, cooling down / solidifying overnight till room temperature, crushing the resulting lignin - sand cake, sieving out particles of 1 - 3 mm, this sample is coded AS.

25 7. Slurrying Granit lignin and sepiolite clay in a weight ratio of 80:20 with water, extruding the resulting paste into 3-5 mm (length) x 2-3 mm (diameter) extrudates, drying/sintering at 140°C, this sample is coded GX.

8. Slurrying Granit lignin and attapulgite clay in a weight ratio of 80:20 with water, extruding the resulting paste into 3-5 mm (length) x 2-3 mm (diameter) extrudates, 30 drying/sintering at 140°C, this sample is coded GY.

9. Slurrying Granit lignin and bentonite clay in a weight ratio of 80:20 with water, extruding the resulting paste into 3-5 mm (length) x 2-3 mm (diameter) extrudates, drying/sintering at 140°C, this sample is coded GZ.

18

It should be noted that the organosolv Alcell lignin is prepared from a mixture of hardwoods (deciduous wood) while the Granit lignin is a purified lignin from the pulp-and paper industry in India, where it is produced by soda pulping of a mixture of wheat straw and Sarkanda grass. It is a representative herbaceous-derived lignin (trade-name 5 Protobind-1000) that is produced by ALM (Asean Lignin Manufacturing) and marketed by GreenValue SA, Switzerland.

Pyrolysis experiments

Batch pyrolysis experiments were conducted with 30 - 50 g of the lignin-additve 10 particles, using an atmospheric pressure, 1 kg/hr bubbling fluidised bed test facility at 400-500°C. Single batches of -30-50 g of the lignin-additive particles were quickly fed into the pre-heated reactor using a cooled screw-feeder. Pre-heated argon (20 ml/min) was used as fluidisation gas and mixed with an additional 1 ml/min of nitrogen from the feedstock bunker and screw. The reactor bed consisted of 600-1000 g silica sand 15 (0.25 mm). Sampling of approximately 20% of the total product gas flow rate was conducted using liquid quenches with iso-propanol (IPA) filled washing bottles.

Sampling was started prior to feeding and continued well after the moment that the permanent gases that originated from the decomposing lignin, ceased to evolve. It is assumed that the main production of reaction water and organic condensables takes 20 place in parallel with the liberation of CO, CO2 and CH4. After the experiment, trapped pyrolysis products were analysed off-line using gas chromatography with mass spectrometric and flame ionisation detection (GC/MS/FID) for the organic components in the IPA-samples.

25 Pyrolysis results

Table 1 compares the yields of a set of GC-detected representative phenolic pyrolysis products that were obtained from the five experiments with lignin-sand 1:1 (m/m) and lignin-clay 1:1 (m/m). The yields are presented in weight percentages that are based on the dry input weight of the Alcell lignin.

30 It should be noted that only a well characterised set of GC-detectable phenolics are presented for comparison. These compounds typically represent 40% of all GC-detected phenolics. The remaining 60% is of unknown origin. Based on their gas chromatographic behaviour (retention time in the chromatogram) it is assumed that 19 they are of phenolic nature. Next to the GC detectables, a large fraction of undetected species originate from the pyrolysis process. This fraction consists of large oligomeric lignin-derived fragments that are not easy to identify. However, by means of a gravimetric method, its yield is estimated as roughly equal or more than the yield of all 5 the GC detectable phenolics combined.

Table 1: Phenolic product yields from the pyrolysis of Alcell lignin at 400°C. Yields are presented in wt.% of the dry input weight of the lignin.

Detected phenolic Alcell- Alcell- Alcell- Alcell- Alcell- compounds Pure Sand Sep Atta Ben 26-Dimethoxyphenol 0.30 0.50 0.44 0.37 0.54 2-methoxy-4-vinyl-phenol 0.06 - 0.10 0.09 0.10 2-Methoxyphenol 0.18 0.27 0.28 0.24 0.32 3-Methoxypyrocatechol 0.17 - 0.22 0.18 0.24 4-Ethylguaiacol 0.05 0.11 0.08 0.08 0.09 4-Methylguaiacol 0.16 0.34 0.30 0.28 0.30 4-Methylsyringol 0.21 0.58 0.43 0.40 0.38

Isoeugenol 0.05 - 0.08 0.07 0.09 P-cresol 0.07 - 0.09 0.11 0.11

Phenol 0.06 0.06 0.08 0.10 0.11

Pyrocatechol 0.23 0.16 0.28 0.26 0.33

Syringaldehyde 0.13 0.15 0.12 0.13 0.18

Vanilline 0.06 0.08 0.04 0.06 0.09

Total 1.73 2.24 2.55 2.38 2.89 10 The use of the clays ensured a smooth feeding procedure without clogging of the feed-tube by molten lignin. Apparently, the porous clays absorb the liquefied lignin and prevent it from sticking to the tube-wall. In case of the pure lignin and the lignin-sand mixture, severe agglomeration was observed in the feed-tube and in the reactor bed, causing fluidisation problems in the reactor bed.

15 Actually, it appeared that with using pure lignin or using lignin in combination with sand, no process for the production of pyrolysed lignin was feasible. Especially a continuous process was not feasible, since the apparatus got clogged. Further, using an 20 extruder, feeding screw, and/or using a fluid-bed reactor appeared to lead to an early stop of the process due to clogging, with concomitant undesired cleaning activities. However, with the clays, the process of the invention could be performed in a continuous way. Further, use of a feeding screw (preferably cooled) and/or a fluid-bed 5 reactor was possible, without clogging, and providing particulate carbonaceous material that can be used in other processes and/or applications.

From Table 1 it is obvious that in the cases where the lignin had been pre-treated with an additive, phenolic yields are 30-70% higher when compared with the untreated sample. The effect is greatest for the samples that were treated with the clays sepiolite, 10 attapulgite and bentonite. When compared with the sand containing sample it shows that the clay-treated lignin produces 6-30% more phenolic compounds.

In addition, the results in Table 1 show higher yields of phenol, cresol and catechols from the pyrolysis of the clay-treated lignins when compared with the pure and sand-treated samples. This might indicate an catalytic cracking effect of the clays.

15 Apparently the cracking effect leads to demethoxylation, demethylation and rearrangements of the main degradation fragments syringols and guaiacols.

For comparison purposes the abovementioned results were obtained from batch tests that were conducted under the same experimental conditions. For practical reasons, these conditions were not optimal for obtaining maximum yields of phenolics.

20 Table 2 compares the results from the pyrolysis of Alcell-Sep (1:1 weight ratio) under optimised conditions with the results for Alcell-Sep from Table 1. The higher 5deIds are probably due to a different sampling procedure, involving a significantly shorter residence time of the hot pyrolysis vapours in the reactor when compared to the residence time that was used for obtaining the results in Table 1.

25 Taking into account the yields of the unknown GC-detected species (5.9 wt.%) and the yield of the gravimetric substance (13.2 wt.%) and assuming that they are of phenolic nature, a total yield of phenolic material of 23.2 wt.% (d.b. (dry base)) was obtained.

30 21

Table 2: Optimisation of the phenolic product yields from the pyrolysis of Alcell lignin at 400°C. Yields are presented in wt.% of the dry input weight of the lignin.

Alcell-Sep, Alcell-Sep,

Detected phenolic compounds results from Table 1 optimised sampling conditions 26-Dimethoxyphenol 0.44 0.73 2-methoxy-4-vinyl-phenol 0.10 0.13 2-Methoxyphenol 0.28 0.36 3- Methoxypyrocatechol 0.22 0.28 4- (2-propenyl)syringone - 0.08 4-Ethylguaiacol 0.08 0.17 4-Methylguaiacol 0.30 0.48 4-Methylsyringol 0.43 1.10

Acetosyringone - 0.03

Isoeugenol 0.08 0.12 P-cresol 0.09 0.02

Phenol 0.08 0.04

Pyrocatechol 0.28 0.24

Syringaldehyde 0.12 0.22

Vanilline 0.04 0.06

Total 2.55 4.07

Table 3 presents the results of the pyrolysis experiments in which the effects of 5 reactor temperature, load and type of additive and type of lignin on the pyrolysis behaviour were investigated.

10 22

Table 3: Results of pyrolysis experiments at 400°C and 500°C with Alcell and Granit lignin, promoted with sepiolite clay, attapulgite clay, bentonite clay, natural magnesium oxide and silica sand. X = sepiolite, Y = atapulgite, Z = bentonite, M = magnesium oxide and S = silica sand.

AX AY AZ AMI AM2 I AS I AX I AY I AZ Temperature [°C] 400 400 400 400 400 4ÖÖ 500 500 500

Additive [wt%d.b.] 20 20 20 20 50 50 20 20 20~“

Gases [wt% d.b.] 8 TT 4 4 14 6 21 17 14~~ C02 [wt% d.b.] Ü8 74) 23 22 ÏOÖ 33 Ï02“^74 43~ C02 [wt% d.b.] 23 23 09 06 32 T9 84 84) ÏJ~ CH4 [wt% d.b.] Ö9 TÏ 05 Ö6 05 Ö6 2.5 23 23~

Oil [wt% d.b.] 43 41 45 33 26 21 39 49 44~~

Water [wt% d.b.] 15 15 13 13 13 9 15 22 ÜT

Methanol [wt% d.b.] T2 T5 T4 T4 Ö9 Ö/7 T4 T2 L2~

Acetic acid [wt% d.b.] 0.4 0.3 0.5 0.3 0.2 0.2 0.4 0.3 0.5

Syringols [wt% d.b.] 3.2 3.0 3.3 1.4 1.1 1.5 2.6 2.1 2.6

Guaiacols [wt% d.b.] 1.7 1.6 1.8 0.9 0.6 0.7 1.5 1.3 1.6

Alkylphenols [wt% d.b.] 0.1 0.1 0.1 0.1 0.0 0.0 0.3 0.3 0.3

Catechols [wt% d.b.] 0.8 0.5 0.9 0.3 0.2 0.1 0.5 0.5 1.0

Unknowns [wt% d.b.] 2.9 2.4 3.0 1.8 0.8 1.3 3.6 2.7 3.5

Oligomerics [wt% d.b.] 18 17 20 14 8 6 14 18 19

Phenolics [wt% d.b.] 27 24 29 18 U 9 23 25 28~

Char [wt% d.b.] 55 54 55 54 39 39 43 45 38~

Mass balance [%] 106 106 104 91 79 66 ÏÖ3 ÏTI 97~ 5

Table 3 continued

I GX I GY I GZ I GX I GY I GZ Temperature [°C] 400 400 400 500 500 5ÖF

Additive [wt%d.b.] 20 20 20 20 20 20

Gases [wt% d.b.] 9 10 Ï1 15 19 18~ C02 [wt% d.b.] 5A 7A 73 62 10.3 10.3 C02 [wt% d.b.] 23 T8 23 63 63 53~ CH4 [wt% d.b.] 08 Ö6 Ï1 22 2A 22~

Oil [wt% d.b.] 41 46 49 61 46 54~ 23

Water [wt% d.b.] I 16 I 19 I 19 I 22 I 19 I 15 Methanol [wt% d.b.] 1.2 1.4 1.2 1.3 1.2 1.0

Acetic acid [wt% d.b.] 0.3 0.3 0.3 0.4 0.2 0.3

Syringols [wt% d.b.] F5 F5 L2 F9 LÏ ÏT“

Guaiacols [wt% d.b.] 3.0 2.9 2.6 3.8 2.4 2.5

Alkylphenols [wt% d.b.] 0.6 0.6 0.6 1.4 1.2 1.2

Catechols [wt% d.b.] Ë2 07 LÖ ÏA 06 (ÜT

Unknowns [wt% d.b.] 3.0 3.1 2.9 5.6 3.6 4.0

Oligomerics [wt% d.b.] 14 17 20 23 17 28

Phenolics [wt% d.b.] 23 25 28 37 26 38

Char [wt% d.b.] 49 47 52 39 35 38~

Mass balance [%] 99 103 112 115 100 fuT

From Table 3 the following conclusions can be deduced: • Effect of temperature: At 500°C more gas, less char, less pyrolysis oil for Alcell, more pyrolysis oil for Granit (due to increased amount of water and 5 oligomers) is produced. In general, at 500 °C more alkylphenols and catechols and less syringols and guaiacols are formed.

• Effect of additive: Promotion with sepiolite, attapulgite and bentonite clay increases the formation of phenolic bio-oil when compared to the promotion with natural magnesium oxide and silica sand. Application of the bentonite clay 10 Z in general leads to the highest yields of phenolics, although the difference with sepiolite X and attapulgite Y are small. The beneficial effect of promoting lignin with clay is illustrated further in Figure 3 for the pyrolysis of Alcell lignin. Effect of lignin type: The herbaceous-derived Granit lignin clearly yields more pyrolysis oil, due to increased levels of (reaction) water and oligomeric 15 fragments. Compared with the deciduous-derived Alcell lignin the Granit-oil contains more alkylphenols and catechols. The pyrolysis oil from Granit contains more guaiacols than syringols, the oil from Alcell lignin is higher in syringiols than in guaiacols.

• Effect of clay load: In general the yields of phenolic compounds from the 20 pyrolysis experiments with the 20 wt% loaded lignins do not seem to differ much from the yields that are obtained with a higher load of clay (50 wt%).

24

Apparently, the main effect of the clay is to facilitate the feeding of the lignin in the reactor.

• On a normalized base, pyrolysis of clay-promoted Alcell lignin yields - on the average- 53 wt% char, 39 wt% oil and 8 wt% gas at 400°C and 43% char, 41 5 wt% oil and 16 wt% gas. Pyrolysis of clay-promoted Granit lignin yields 47 wt% char, 43 wt% oil and 10 wt% gas at 400°C and 34 wt% char, 49 wt% oil and 16 wt% gas at 500°C. The results for the magnesium oxide and sand promoted Alcell lignin indicate a less effective pyrolysis of the Alcell lignin. Indeed it was observed that the application of magnesium oxide and sand did 10 not prevent bed-agglomeration problems that were absent when using the clay- promoted lignin. Thus, a pyrolysis process with such additives is less feasible, due to problems in the reactor (see also below).

• In general, the clay promoted lignins can be pyrolysed without operational problems due to melting and bed agglomeration. The bio-oil product typically 15 contains up to 10 wt% (d.b. of the original lignin feed) of monomeric phenols, predominantly methoxyphenols (syringols and guaiacols). Total yield of phenolic substances (monomeric and oligomeric) varies from 23 to 38 wt%. These yields imply that the bio-oil is an interesting feedstock for a variety of applications.

20

Claims

A method for thermolysis of biomass comprising: a. Pretreatment of a mixture comprising the biomass, wherein the biomass comprises lignin, and a clay, wherein the pretreatment comprises pelletizing the mixture, to provide a pelletized starting material; b. introducing the pelletized starting material obtained at a) into a reactor; and 10 c. pyrolizing the pelletized starting material in the reactor.

The method of claim 1, wherein the biomass comprises technical lignin.

A method according to any one of the preceding claims, wherein the biomass comprises a lignin from the pulp and paper industry or a lignin from the production of second generation biofuels.

The method of any one of the preceding claims, wherein the clay comprises hormite clay.

The method of any one of the preceding claims, wherein the clay comprises bentonite clay.

6. A method according to any one of the preceding claims, wherein the clay comprises sepiolite clay.

The method of any one of the preceding claims, wherein the clay comprises attapulgite clay.

The method of any one of the preceding claims, wherein the clay comprises montmorrilonite clay.

The method according to any of the preceding claims, wherein the biomass and the clay are mixed in a weight ratio of 90:10 to 10:90 based on the dry weight of the materials.

10. Method as claimed in any of the foregoing claims, wherein the pretreatment comprises (a1) providing a paste of biomass, clay and water, (a2) extruding the paste, (a3) providing a particulate material, and (a4) drying the particulate material to provide the pelletized starting material.

The method of any one of the preceding claims, wherein the pelletized starting material comprises pellets that have average dimensions in the range of 0.25-10 mm.

12. A method according to any one of the preceding claims, wherein the reactor is a fluid bed reactor.

A method according to any one of the preceding claims, wherein the thermolysis is carried out at a temperature in the range of 300-700 ° C, in particular in the range of 350-550 ° C.

A pelletized end product obtainable according to the method according to one of the preceding claims.

A pelletized carbonaceous product comprising pellets having average dimensions in the range of 0.25-10 mm, wherein the pellets comprise thermolysed lignin, and wherein the pellets comprise carbon in an amount of 5-60% by weight, oxides of magnesium and silicon in an amount of 30-95% by weight, and 0-10% by weight of other materials, based on the total weight of the pellets on a dry weight basis.

Use of the pelletized carbon product according to one of the preceding claims, as a soil improver.

17. Use of the pelletized carbon-shaped product according to any of claims 14-15, as a precursor for activated carbon.

Use of the pelletized carbonaceous product according to any of claims 14-15 as a lignin-based cracking catalyst.

Use of the pelletized carbonaceous product according to any of claims 14-15 as a CO2 neutral fuel.

Use of the method according to any of claims 1-13 to provide bio-char (bio char) and bio-oil of lignin.