EP4638359A1

EP4638359A1 - A novel biorefinery method of making green graphite products

Info

Publication number: EP4638359A1
Application number: EP23838010.9A
Authority: EP
Inventors: Weihong Yang; Tong HAN
Original assignee: Nordic Bio Graphite AB
Current assignee: Nordic Bio Graphite AB
Priority date: 2022-12-21
Filing date: 2023-12-21
Publication date: 2025-10-29
Also published as: SE2550543A1; WO2024133695A1

Abstract

The invention relates to a novel cascaded biorefinery method of making green practical graphite products, more specifically, to the method of making a graphite product from biomass comprising biomass pyrolysis to produce biochar and biooil, catalytic graphitization of the biochar to produce a graphite powder, shaping the graphite powder with the use of a binder and subjecting the shaped product to heat treatment, wherein the binder comprises the heavy fraction of the biooil subjected to heat treatment The invention also relates to a graphite product produced by the method.

Description

A NOVEL BIOREFINERY METHOD OF MAKING GREEN GRAPHITE PRODUCTS

TECHNICAL FIELD

The invention relates to a novel cascaded biorefinery method of making green practical graphite products.

BACKGROUND

Graphite products have a various industrial applications including refractories, batteries, steelmaking, expanded graphite, brake linings, foundry facings and lubricants. Graphite products are made of either natural graphite or artificial. Natural graphite is mined from natural mineral deposits subject to geographical restrictions. Owing to the expansion of graphite powders, the excavation process causes extremely serious pollution such as sparkling night air, damaged crops, homes and belongings. Furthermore, a series of energy- and chemical- sensitive processes are indispensable for the purification of natural graphite. Artificial graphite products are manufactured via series complex processes: calcination, compounding, kneading, pressing, roasting, graphitization and machining. The production cycle of artificial graphite is as long as 50 days, and ultra-high power graphite electrode requires at least 65 days. Petroleumbased or coke-based needle coke is the primary raw material and coal bitumen is the primary binder used for the production of the graphite electrode. The rapidly expanding electric vehicle market leads to a rise in the demand for needle coke and coal bitumen. Due to the low-carbon development strategy of the word, the supply of the fossil-based needle coke and bitumen will become even more intense. More importantly, the graphitization process requires an ultra-high temperature between 2500 and 3500 °C and a long period time of 1 to 2 days. The energy consumption of the process is believed to be extremely high.

Catalytic graphitization has been proven to be able to convert renewable carbon source such as biomass, biomass derived biochar and other carbon-rich organic materials into graphitic carbon within a few hours at a temperature lower than 1500 °C (A. Oya and H. Marsh, "Phenomena of catalytic graphitization," Journal of Materials Science, vol. 17, no. 2, pp. 309-322, 1982). Patent publication WO 2016/130026 provides a method of producing graphite comprising heating at least one of tar, char and biomass in the presence of a catalyst to a temperature sufficient to produce graphite. All these suggest catalytic graphitization of biomass-based materials represents a low energy-consumption and sustainable technical route to produce graphite powders. The market of biomass pyrolysis biochar is evaluated to reach a CAGR over 10% in Europe in coming decades. Therefore, a biomass biorefinery method of making practical green graphite products is of great significance and has great potential to replace today's industrial graphite products production process.

SUMMARY OF THE INVENTION

The invention provides a novel biorefinery method of making fossil free, ecologically clean graphite products from biomass, combing biomass pyrolysis, catalytic graphitization of biochar, acid washing and shaping using a heat-treated biooil derived binder. For the graphite products production, alongside sustainable catalyst removal and recycling process, a renewable, fossil-free binder is also essential. The inventors have developed a new alternative method of making green graphite products using biomass pyrolysis to produce biooil and catalytic graphitization that also involves the use of the produced biooil. It has been unexpectedly found that the heavy fraction of the biomass pyrolysis oil, tar, can be used as a renewable binder as alternative to coal bitumen in the shaping process. Using different amounts of the heavy fraction of biooil as a binder to manufacture shaped graphite products was the first attempt of this study but failed. Relatively lower viscosity value of the heavy fraction of biooil than commonly used binders (asphalt) was thought to be the main reason. Therefore, the heavy fraction of biooil was subjected to heat treatment, which significantly increased the viscosity of biooil, and the use of the heat-treated heavy fraction of biooil as a binder showed much more promising results compared to that using raw biooil as binder. This said, the light fraction of the biooil can be used as a partial substitute for one or more inorganic acids used for the catalyst removal via washing with one or more inorganic acids.

Accordingly, in a first aspect, the invention provides a method of making a graphite product from biomass comprising biomass pyrolysis to produce biochar and biooil, catalytic graphitization of the biochar to produce a graphite powder, shaping the graphite powder with the use of a binder and subjecting the shaped product to heat treatment, wherein the binder comprises the heavy fraction of the biooil subjected to heat treatment.

In one embodiment, the weight of the heavy fraction of the biooil subjected to heat treatment is from about 5 to 50% of the weight of the graphite powder.

In one embodiment, the weight of the heavy fraction of the biooil subjected to heat treatment is from about 30 to 35% of the weight of the graphite powder.

In one embodiment, the shaped product is subjected to heat treatment at temperature of about 800 to about 1300 °C for a duration time of about 1 to 3 hours, preferably at a temperature of about 800 °C for a duration time of about 1 hour. Thus, the graphite powder may be subjected to heat treatment at a temperature of about 800°C for a duration time of about 1 hour.

In one embodiment, the heating rate is over 50 °C/min.

In one embodiment, the heavy fraction of the biooil is used as a dispersant to the graphite powder.

In one embodiment, the heavy fraction of the biooil comprises from about 1% to 30% of water by weight.

In one embodiment, the heavy fraction of the biooil is subjected to heat treatment at a temperature from about 30 to 100 °C for a duration time of about 10 to 100 hours.

In one embodiment, the viscosity of the heavy fraction of the biooil subjected to heat treatment is over 20 times higher compared to the viscosity of the original heavy fraction of the biooil.

In one embodiment, the viscosity of the heavy fraction of the biooil subjected to heat treatment is about 5 to 50 mm²/s. Thus, the viscosity of the heavy fraction of the biooil may be about 5 to 50 mm²/s.

In one embodiment, the biomass is sawdust.

In one embodiment, the biomass pyrolysis occurs at a temperature of about 350 to 800 °C.

Herein, the term “catalyst” refers to a catalyst of the catalytic graphitization.

In one embodiment, the catalyst is directly mixed with or impregnated into biomass. The catalyst may thus be added to the biomass to be pyrolyzed. In other words, the catalyst may be added to the biomass prior to pyrolysis thereof. The catalyst may accordingly be present in the biomass during pyrolysis thereof, as well as in the biochar and biooil produced by the pyrolysis. It is contemplated that presence of the catalyst in the produced biooil facilitates separation thereof by gravity into a light fraction and a heavy fraction.

In one embodiment, the catalyst is directly mixed with or impregnated into biochar.

In one embodiment, the catalyst is a metal catalyst.

In one embodiment, the metal is a transition metal.

In one embodiment, the transition metal is iron, copper, manganese, cobalt or nickel.

In one embodiment, the metal catalyst is a metal, metal alloy, metal salt or metal oxide.

In one embodiment, the metal is iron.

In one embodiment, the catalytic graphitization occurs at a temperature of about 800 to 2000 °C.

In one embodiment, the method further comprises the catalyst removal and recycling.

In one embodiment, the catalyst removal occurs via washing with one or more inorganic acids. In one embodiment, the washing is carried out via hydrochloric acid and then aqua regia under ultrasound.

In one embodiment, the light fraction of the biooil is used as a partial substitute for one or more inorganic acids. Thus, catalyst removal may occur by washing with a composition comprising the light fraction of the biooil and one or more organic acids.

In one embodiment, the catalyst recycling occurs by evaporation of waste acids. Evaporation of waste acids leaves behind metal salt, which may be recycled as catalyst. In other words, the catalyst recycling may occur by evaporation of waste acids with metal ions or by evaporation of catalyst containing acidic solution.

In a second aspect, the invention provides a graphite product produced by the method of invention.

In one embodiment, the graphite product is selected from the group consisting of graphite electrodes, accessories and graphite based thin films.

In one embodiment, the biooil is separated into a light fraction and a heavy fraction. The biooil is preferably separated into the light fraction and the heavy fraction by gravity.

BRIEF DESCRIPTION OF DRAWINGS

FIG. I shows the XRD pattern of biochar as raw material.

FIG.2 shows the XRD pattern of a sample graphitized at 800°C with 11.2% of iron (III) nitrate loading of the weight of biochar via wet impregnation (BC-800-11.2-WET- FENO)

FIG.3 shows the XRD pattern of a sample graphitized at 1300°C with 22.4% of iron (III) nitrate loading of the weight of biochar via wet impregnation (BC-1300-22.4- WET-FENO)

FIG.4 shows the XRD pattern of a sample graphitized at 1300°C with 33.6% of iron (III) nitrate loading of the weight of biochar via wet impregnation (BC- 1300-33.6- WET-FENO) FIG.5 shows the XRD pattern of a sample graphitized at 1300°C with 22.4% of iron loading of the weight of biochar via direct mixing (BC-1300-22.4-DRY-FE)

FIG.6 shows the XRD pattern of a sample graphitized at 1300°C with 22.4% of iron (III) nitrate loading of the weight of biochar via direct mixing (BC-1300-22.4- DRY-FENO).

FIG.7 shows the particle size distribution of an optimal sample graphitized at 1300°C with 22.4% of iron (III) nitrate loading of the weight of biochar (BC-1300-22.4-WET- FENO).

FIG.8 shows the Raman spectra of a graphitized sample derived from biochar at 1300°C for 3h at 22.4% of catalyst of the weight of biochar (BC-1300-22.4-WET- FENO).

FIG.9 shows the SEM image of BC-1300-22.4-WET-FENO.

FIG.10 shows the appearance of raw biooil that can be separated into a heavy fraction and a light fraction.

FIG.11 shows the appearance of the original heavy fraction of the biooil.

FIG.12 shows the appearance of the heavy fraction of the biooil subjected to heat treatment.

FIG.13 shows the appearance of a graphite electrode sample mixed with the heavy fraction of biooil after heat treatment.

FIG.14 shows the appearance of a shaped but deformed (during heating treatment) graphite electrode sample.

FIG. 15 shows the appearance of a shaped but fragile graphite electrode sample.

FIG.16 shows the appearance of a graphite electrode sample produced according to the preferable embodiment of the invention.

FIG.17 shows a shaped graphite sample in other shape. FIG.18 shows a shaped graphite sample in other shape.

FIG.19 shows a general scheme of the method according to the disclosure.

MODES FOR CARRYING OUT THE INVENTION

General description of the method

With reference to FIG.19, the method can be described as follows. Raw biomass (“Biomass”), for example sawdust, is subjected to pyrolysis (“Pyrolysis”) to produce biochar (“Biochar”) as well as, during the process of condensation (“Condensation”), raw biooil (“Biooil”) and exit gases (“Gases”). The raw biooil is separated (“Separation”) into light and heavy fractions (“Light fraction” and “Heavy fraction”). The heavy fraction is further subjected to heat treatment (“Heat treatment”). To the biochar, a catalyst is added (“Impregnation”). Alternatively, the catalyst is added to the raw biomass prior to subjecting it to pyrolysis. After that the graphitization is carried out (“Graphitization”), the catalyst is recovered via acid washing (“Acid washing”), to produce a graphite powder (“Graphite powders”). The recovered catalyst can be reused in the process. The heavy fraction of the biooil subjected to heat treatment is added to the graphite powder, and the process of shaping (“Shaping”) begins, which is followed by heat treatment (“Heat treatment”) to produce the final ecologically clean graphite product (“Practical graphite products”). A more detailed description of example embodiments of the method is presented below.

Production of biochar, light and heavy fractions of biooil, and graphite powders

Biomass pyrolysis was performed in an auger reactor heated by a resistive electric heating element at a temperature of 550°C by using softwood sawdust as raw biomass to produce biochar and, in the process of condensation, raw biooil and waste gases. Produced biochar was then used as a raw material for a catalytic graphitization process to produce graphite powders. Produced biooil was separated into the light and heavy fractions by gravity. Elemental compositions of biomass, biochar, light and heavy fractions of biooil and graphite powders are summarized in Table 1. Table 1. Elemental composition of biomass, biochar, biooil, and produced graphite powders.

Biooil Biooil

Biomass Biochar (Heavy) (Light) Graphite

Elemental analysis (Wt.%, dry basis)

C 50.70 83.50 59.53 22.19 97.63

H 6.30 2.68 8.5 10.72 0.04

N 0.12 0.26 0.07

S <110ppm 0.21

O ^a 42.5 13.35 31.50 66.64

A more detailed description of the graphitization process is presented below.

Catalytic graphitization of biochar

Iron (III) nitrate (Fe (NOs)3 9H2O, analytical grade), iron powders were used as catalysts. Catalysts were added into the biochar via methods including wet impregnation and direct mixing. The catalytic graphitization occurred in a batch type rotation reactor.

For the addition way of wet impregnation, iron (III) nitrate was first dissolved into deionized water. The mass ratios of added iron (III) nitrate to biochar were altered according to the following amounts of iron: 0, 11.2%, 22.4%, and 33.6% of the weight of the biochar. Then biochar was added into the iron (III) nitrate solutions. Formed biochar slurries were stirred evenly using a magnetic stirrer for a time of 5 hours, for the iron ions impregnation on the biochar surface. Thereafter, the biochar slurries were moved to a drying oven for drying at a temperature of 105 °C. For the addition by way of direct mixing, iron nitrate and iron were just put into biochar powders, and followed by mechanic stirring for evenly mixing, respectively. Used amount of iron is fixed as 22.4% of the weight of biochar. Produced graphite samples were labelled as “Graphite- Temperature-Loading-Duration time-Addition way-Catalyst”, such as G-1300-22.4- 3h-WET-FENO. For both two addition ways, mixtures of biochar and catalyst were put into an electrical furnace for catalytic graphitization under Nitrogen atmosphere (200ml/min) at a temperature of 1300 °C for a period time of 3 hours. The heating rate of the heating process is fixed at 10 °C/min. Collected samples from the furnace were then put for acid washing to remove catalyst from the graphite.

Acid washing was carried out in three different steps, using different acids: acetic acids (representative sample of the light fraction of biooil), hydrochloric acid, and aqua regia. For each step, samples after heat treatment were put into a container with a certain amount of acids for washing under ultrasound. After each step, samples were dried and analyzed for ash and iron content. The removal efficiency of each acid was calculated according to the iron content decrease. The final obtained graphite products were then characterized by using XRD, Raman spectrum, SEM, and particle size distribution (PSD) analyzes. Waste catalyst containing acidic solutions was evaporated at a temperature of around 90 °C to recycle catalysts. The recycling efficiency was calculated according to the ratio of catalyst amount recycled-to-catalyst amount input.

The XRD patterns for the resulting graphitized samples are shown in FIGS.2-6. The XRD pattern of biochar as raw material is shown in FIG. l, for comparison. Graphite is shown most distinctly by the (002) peak near 29 = 26.55°, which can be seen obviously in all treated samples, while the other peaks for the (100), (101), (004), and (110) planes are relatively weak. In the control sample, which was not treated by a catalyst, a broad band with no distinct peak at 29 = 26.55° can be observed, representing high amounts of disordered carbon. Both the broad band and the sharp band which are made up of amorphous carbon at 25°, turbostratic carbon from 25.8° to 26.2°, and graphitic carbon at 26.55°, exist in all treated samples. Table 2 summaries the crystallite size of the graphite in nanometers for each sample (Lc), calculated using the Scherrer equation (A. Oya and H. Marsh, "Phenomena of catalytic graphitization," Journal of Materials Science, vol. 17, no. 2, pp. 399-322, 1982), based on the position of the (992) peak. From this, the interlayer spacing (d992) was calculated, and used to find the graphitization degree parameter (g), used by Maldonado-Hodar et al (F. Maldonado- Hodar, C. Moreno-Castilla, J. Rivera-Utrilla, Y. Hanzawa, and Y. Yamada, "Catalytic graphitization of carbon aerogels by transition metals," Langmuir, vol. 16, no. 9, pp. 4367-4373, 2000). The G values quantitatively characterize the degree of order for graphene layer stacking and degree of conversion from turbostratic carbon to graphitic carbon. The d002 value of the sample (G-1300-22.4-WET-FENO) is quite smaller than other treated samples, and its G% value is as high as 91.93%, indicating that the graphitic structure in this sample is very close to pure graphite.

Table 2. Calculated crystalline qualitative and quantitative analysis values of produced graphite powders.

Sample name doo2 (nm) G (%) Lc (nm) La (nm) a (%)

G-800-11.2-3h-WET-FENO 0.3406 39.10 5.26 2.71 56.16

G-l 100-11.2-3h-WET-FENO 0.3407 38.43 6.27 4.67 74.54

G-1300-11.2-lh-WET-FENO 0.3397 50.32 10.45 2.71 51.09

G-1300-11.2-3h-WET-FENO 0.3382 68.00 11.82 10.20 62.61

G-1300-11.2-6h-WET-FENO 0.3376 73.85 12.55 14.85 76.95

G-1300-22.4-3h-WET-FENO 0.3361 91.32 16.00 13.20 78.38

G-1300-33.6-3h-WET-FENO 0.3363 89.03 18.56 8.96 82.81

G-1300-22.4-3h-DRY-FENO 0.3364 88.42 18.54 12.78 59.85

G-1300-22.4-3h-DRY-FE 0.3387 62.11 17.36 13.55 61.51

Particle size distribution (PSD)

Particle size is a unique parameter to quantify meaningfully for some forms of carbon material. In the case of synthetic flake graphite, the particle size is relatively easy to determine, i.e. as the diameter of the sphere. The results (FIG.7) show that this sample has a more concentrated distribution than other commercial graphite (H. Li, H. Zhang, K. Li, J. Zhang, M. Sun, and B. Su, "Catalytic graphitization of coke carbon by iron: Understanding the evolution of carbon Structure, morphology and lattice fringes," Fuel, vol. 279, p. 118531, 2020). The average particle size (D50) of the sample is 18 pm, which is a proper size for a graphite anode in lithium-ion batteries. Therefore, there is less specific surface area for the formation of a solid electrolyte interphase (SEI) layer. The PSD analysis results of the optimal sample are shown in Table 3.

Table 3. Particle size distribution results of produced graphite powders (G-1300- 22.4-WET-FENO).

Particle size (um)

Sample

D10 D50 D90

Graphite 5.064 18.009 96.415

AGP-818 (commercial 10-13 18-20 55 graphite)

Raman

With reference to FIG.8, the first-order Raman spectrum is characterized by two peaks: the disorder-induced peak (D-band) at a wavelength of around 1350 cm’¹ and the graphite peak (G-band) at around 1580 cm’¹. The intensity of the D-peak and the G- peak are related to the ordering of the graphitic structure (M. Dresselhaus, G. Dresselhaus, and M. Hofmann, "The big picture of Raman scattering in carbon nanotubes," Vibrational Spectroscopy, vol. 45, no. 2, pp. 71-81, 2007; A. C. Ferrari, "Raman spectroscopy of graphene and graphite: Disorder, electron-phonon coupling, doping and nonadiabatic effects," Solid state communications, vol. 143, no. 1-2, pp. 47- 57, 2007). ID/IG, the ratio of the intensities of the D-band and the G-band, is a measure of the degree of order, where a lower ratio indicates a lower disorder and higher amounts of graphite. The ID/IG ratio of BC-1300-22.4 is 0.3428 with corresponding La values of 19.01 nm, which implies that the presence of a catalyst promotes the reordering of the carbon structure at lower temperature. Another evidence of the graphitic structure can be found in the broad band around 2700 cm'¹. This band is a result of second order resonance from the D-band, and can be called the G', 2D or D* band which is characteristic of stacked graphene layers. These results suggest that the catalysts are able to substantially lower the driving force, achieving similar graphitization to those at much higher temperatures, and reducing the energy required during production. The Raman spectra agrees with the results shown by the XRD patterns, indicating a great amount of graphitization in BC-1300-22.4-WET-FENO. The bands of Raman spectra in the sample are not nearly as sharp as pure graphite, however it performs a better graphitization compared with those artificial graphite materials derived directly from biomass (I. Major, J.-M. Pin, E. Behazin, A. Rodriguez-Uribe, M. Misra, and A. Mohanty, "Graphitization of Miscanthus grass biocarbon enhanced by in situ generated FeCo nanoparticles," Green Chemistry, vol. 20, no. 10, pp. 2269-2278, 2018.)

SEM images of artificial graphite, BC-1300-22.4-WET-FENO, reveals that 10-20 pm diameter plate-like graphite materials are homogeneously distributed on the matrix. In FIG.9, most flakes are ~15 pm wide and ~5 pm thick. In fact, the morphology of BC-1300-22.4-WET-FENO graphite flakes looks very similar to commercial artificial graphite produced from biomass. From the SEM micrographs of materials, the distribution of particle sizes is consistent with results obtained from particle size distribution analysis.

Acid washing and catalyst recycling

After graphitization, the product contains iron residues including iron (bcc), iron oxides, and iron carbides. To recycle catalyst as much as possible, graphitized sample was firstly washed by using nitric acid for three times, aiming to obtain iron ions. The solution was then dried at 120 °C, where nitric acid evaporated and a conversion from iron (III) nitrate into iron oxide was achieved. The rest of iron residues in products was further removed by heating the products in aqua regia solution using a digestion microwave system at 200 °C for 30 min. The products were then washed with additional deionized water until a neutral pH was reached, and finally dried at 120 °C. Same burning test was performed to the final products, the result shows that catalyst residues were decreased to 0.18% in graphite powders, indicating its potential as commercial graphite.

Graphite products fabrication

The process of heat treatment of the heavy fraction of biooil was performed at a temperature of 80 °C for a duration time of 72 hours. Appropriate parameters of the fabrication process were considered for the preparation of a well-shaped and compact graphite product. Aproper amount of the heavy fraction of biooil is a primary parameter. The amount of the heat-treated heavy fraction of biooil of between 30% and 35% of the weight of the graphite powder was verified to be preferred. When the amount of biooil used is lower than this value, it may be difficult to form graphite products, and when it is higher than this value, the product may be deformed in the subsequent process, as shown in FIG.13-15. The graphite product produced according to the preferable embodiment of the invention is shown in FIG.16. The proper heating rate of the heat treatment process is another parameter. Relatively high heating rate (higher than 50 °C/min) was proven to be preferential for a compact graphite product. Applying medium or low heating rate may induce the production of shaped but fragile sample. All information is summarized in Table 4. The photos of raw biooil, original heavy fraction of biooil, and heavy fraction of biooil subjected to heat treatment are shown in FIG.10-12, respectively. Graphite products in other shapes fabricated according to the optimized process parameters are shown in FIG.17 and 18, clearly demonstrating a satisfactory shape of the products. Table 4. Performed graphite powders shaping cases and quality of corresponding shaped graphite products

Mixing Extrusion Heat treatment Shaped products

Binder content

Binder (heavy icinpciaiuic Program (Heating rate; Temperature; fraction of Pressure (MPa) Quality (Status; Evaluation) biooil) weight of the (°C) ^Timc) graphite powder)

1 Original 20%-25% ~ 25 ^ 10 - Out of shape; low viscosity of binder

2 Original 30%-35% ~ 25 ^ 10 - Out of shape; low viscosity of binder

3 Heat-treated 10%-15% ==» 100 ^ 10 - Out of shape; low binder content

4 Heat-treated 20%-25% ==« 100 ^ 10 - Out of shape; low binder content

5 Heat-treated 30%-35% ==« 100 ==» 10 Low (0.5-5 °C/min); 800 °C; Ihour Shaped but fragile; low binder fixation amount

6 Heat-treated 30%-35% ==« 100 ==» 10 Medium (5-50 °C/min); 800 °C; Shaped but fragile; low binder fixation amount

7 Heat-treated 30%-35% ==« 100 ==» 10 High (>50 °C/min); 800 °C; Ihour Shaped;

8 Heat-treated 30%-35% ==« 100 ==» 10 High (>50 °C/min); 800 °C; 3hour Shaped;

9 Heat-treated 30%-35% ==« 100 ==» 10 High (>50 °C/min); 1300 °C; 3hour Shaped;

10 Heat-treated 40%-45% ==» 100 ==» 10 High (>50 °C/min); 1300 °C; 3hour Deformed during heating; high binder content

Claims

1. A method of making a graphite product from biomass comprising biomass pyrolysis to produce biochar and biooil, catalytic graphitization of the biochar to produce a graphite powder, shaping the graphite powder with the use of a binder and subjecting the shaped product to heat treatment, wherein the binder comprises the heavy fraction of the biooil subjected to heat treatment.

2. The method of claim 1, wherein the weight of the heavy fraction of the biooil subjected to heat treatment is from about 5 to 50 % of the weight of the graphite powder.

3. The method of claim 2, wherein the weight of the heavy fraction of the biooil subjected to heat treatment is from about 30 to 35 % of the weight of the graphite powder.

4. The method of any of the preceding claims, wherein the shaped product is subjected to heat treatment at a temperature of about 800 to 1300 °C for a duration time of about 1 to 3 hours.

5. The method of claim 4, wherein the heating rate is over 50 °C/min.

6. The method of any of the preceding claims, wherein the heavy fraction of the biooil is a dispersant to the graphite powder.

7. The method of any of the preceding claims, wherein the heavy fraction of the biooil comprises from about 1 % to 30 % of water by weight.

8. The method of any of the preceding claims, wherein the heavy fraction of the biooil is subjected to heat treatment at a temperature from about 30 to 100 °C for a duration time of about 10 to 100 hours.

9. The method of any of the preceding claims, wherein the viscosity of the heavy fraction of the biooil subjected to heat treatment is over 20 times higher compared to the viscosity of the original heavy fraction of the biooil.

10. The method of any of the preceding claims, wherein the viscosity of the heavy fraction of the biooil subjected to heat treatment is about 5 to 50 mm²/s.

11. The method of any of the preceding claims, wherein the biomass is sawdust.

12. The method of any of the preceding claims, wherein the biomass pyrolysis occurs at a temperature of about 350 to 800 °C.

13. The method of any of the preceding claims, wherein the catalyst is directly mixed with or impregnated into the biomass.

14. The method of any of the preceding claims, wherein the catalyst is directly mixed with or impregnated into the biochar.

15. The method of any of the preceding claims, wherein the catalyst is a metal catalyst.

16. The method of claim 15, wherein the metal is a transition metal.

17. The method of claim 16, wherein the transition metal is iron, copper, manganese, cobalt or nickel.

18. The method of claim 15, wherein the catalyst is a metal, metal alloy, metal salt or metal oxide.

19. The method of claim 18, wherein the metal is iron.

20. The method of any of the preceding claims, wherein the catalytic graphitization occurs at a temperature of about 800 to 2000 °C.

21. The method of any of the preceding claims, further comprising catalyst removal and recycling.

22. The method of claim 21, wherein the catalyst removal occurs by washing with one or more inorganic acids.

23. The method of claim 22, wherein the washing is carried out by hydrochloric acid and then aqua regia under ultrasound.

24. The method of claim 22 or 23, wherein the light fraction of the biooil is used as a partial substitute for one or more inorganic acids.

25. The method of any of claims 21 to 24, wherein the catalyst recycling occurs by evaporation of waste acids.

26. The method of any of the preceding claims, wherein the biooil is separated into a light fraction and a heavy fraction.

27. The method of claim 26, wherein the biooil is separated into the light fraction and the heavy fraction by gravity.

28. A graphite product produced by the method of any of claims 1 to 27.

29. The graphite product of claim 28, wherein the graphite product is a graphite electrode or a graphite based thin film.