Mechanical activation of biomass for hydrothermal liquefaction

Abstract

A method is provided for obtaining a biocrude intermediate by hydrothermal liquefaction of plant waste. Using a waste feed material with a high cellulose content, the method includes: grinding the waste feed material to obtain a powdered waste feed material; and subjecting the powdered waste feed material to hydrothermal liquefaction at a temperature of 250° C. or higher. Above this temperature, no catalyst is required to obtain the biocrude. Lower temperatures, such as temperatures above about 150° C., can also be used in the presence of a catalyst. Grinding the plant material, such as ball milling, reduces particle size and crystallinity and, when combined with processing at high temperatures, increases the yield of the biocrude. The biocrude can be upgraded to a biofuel by subjecting it to high temperature hydrodeoxygenation in the presence of hydrogen. Plant waste that would otherwise contribute to greenhouse gases is instead converted to fuel.

Description

[Technical field]

[0001] Related Applications This application claims the benefit of U.S. Provisional Application No. 63 / 336,930, entitled “Mechanical activation of biomass for hydrothermal liquefaction,” filed April 29, 2022 (inventors: Michael Timko, Heather LeClerc, Andrew Teixeira, Geoffrey Tompsett, and Alex Maag), which is incorporated herein in its entirety.

[0002] government support This invention was developed in part with United States Government support under Contract No. DE-EE0008513 awarded by the Department of Energy. The Government has certain rights in this invention. [Background technology]

[0003] background Biofuel and bioenergy production has the potential to reduce greenhouse gas emissions, improve energy security, and reduce energy price volatility. Hydrothermal liquefaction is a method to convert organic, water-containing waste into biofuels and bioenergy. The biggest obstacle in hydrothermal liquefaction is producing a biocrude intermediate that can be upgraded to a final fuel. Wastes such as yard waste or green waste are abundant and cheap. The United States generates about 50 million tons of these types of waste annually. See: National Overview: Facts and Figures on Materials, Wastes and Recycling.” EPA, Environmental Protection Agency, 29 June 2022. Moreover, these wastes have no use because they do not provide sufficient biocrude yields to be economically viable. When disposed of in landfills, these wastes contribute to carbon dioxide and methane pollution. Summary of the Invention [Problem to be solved by the invention]

[0004] Therefore, there is a need for a process that uses plant-derived waste, such as yard waste or green waste, to produce biocrude intermediates in sufficient quantities to be economically viable. [Means for solving the problem]

[0005] overview One aspect of the invention described herein provides a method for obtaining a biocrude intermediate by hydrothermal liquefaction of cellulosic waste, the method comprising: obtaining a waste feed material having a high cellulose content; grinding the waste feed material to obtain a powdered waste feed material; and subjecting the powdered waste feed material to hydrothermal liquefaction at a temperature above 250°C, thereby obtaining a biocrude intermediate; The above processes provide a double benefit to the ecology of the planet since waste feedstock would otherwise pollute the environment with greenhouse gases carbon dioxide and, even worse, methane gas as it decays and occupies landfill sites, and these processes also provide biofuels. These processes are effectively used without the addition of chemical catalysts and without the addition of enzymes. Process embodiments using temperatures below 250° C. are also suitable in the presence of catalysts, for example, common zeolites such as ZSM-5, HY, ZSM-11, ZSM-23 and Beta can be used at lower temperatures with comparable results.

[0006] Thus, for various embodiments of the method, the waste feedstock comprises at least one of green waste, garden waste, zoo waste feedstock, zoo herbivore feces, floriculture waste, agricultural waste, beverage industry waste such as grape pomace, food waste, inedible vegetable waste, marine algae, freshwater algae, paper processing waste and plant parts such as lignin, and wood waste such as sawdust.

[0007] To produce biofuel, the method further includes upgrading the biocrude intermediate to obtain a biofuel or bio-oil. One embodiment of upgrading is a process in which the biocrude intermediate is subjected to high temperature hydrodeoxygenation in the presence of hydrogen, thereby removing oxygen.

[0008] In various embodiments, the grinding of the waste feed material further comprises at least one of the following: ball milling, pin milling, hammer milling, jet milling, two-roll milling, colloid milling, wet disk milling, and vibratory milling. In various embodiments, the biocrude intermediate resulting from the process using grinding has been found to be greater than 20 wt% of the waste feed material, greater than 25 wt% of the waste feed material, or greater than 30 wt% of the waste feed material.

[0009] The biocrude obtained by this method exceeds that of conventional methods, including using co-solvent enhanced lignin separation (CELF), and other methods of separating plant material and obtaining lignin, such as organosolv lignin and enzymatic lignin. These conventional processes were developed to solubilize and remove lignin from cellulose so that sugars can be obtained from the cellulose or so that paper can be produced from the cellulose fraction. The lignin and cellulose fractions are also suitable plant materials for the methods herein to obtain biocrude, if they are not used to manufacture other commercial products.

[0010] In various embodiments, subjecting the powdered waste feed material to hydrothermal liquefaction includes treating the powdered waste feed material at a temperature of about 250°C to about 400°C. The temperature can be from about 250°C to about 275°C, or from about 275°C to about 350°C, or from about 300°C to about 350°C to about 400°C. In the presence of a catalyst, lower temperatures are effective to cause hydrothermal liquefaction, such as from 150°C to 75°C, or from 180°C to 225°C. The high temperature treatment is, in various embodiments, for a period of at least about 25-55 minutes, 30-60 minutes to about 35-65 minutes. This temperature is higher than previous green waste treatments used, for example, to obtain sugar monomers from cellulose, a process in which enzymes have also been used. The methods herein do not rely on, require, or use enzymes.

[0011] In various embodiments, the grinding step results in particles of the pulverulent waste feed material having a size of less than about 0.2 mm, less than 0.15 mm, less than 0.10 mm, less than 0.05 mm (50 micrometers), less than 0.025 mm (25 micrometers), or less than about 0.01 mm (10 micrometers). Surprisingly, these minimum observed sizes are approximately the same as the size of a plant cell. Grinding results in particles of the pulverulent waste feed material having reduced crystallinity as determined by analysis by powder x-ray diffraction.

[0012] One aspect of the invention herein provides a method for increasing the yield of a biocrude intermediate from plant waste by hydrothermal liquefaction, the method comprising: obtaining a waste feed material having a high cellulose content; grinding the waste feed material to obtain a powdered waste feed material of smaller particle size, thereby reducing particle size; and subjecting the powdered waste feed material to hydrothermal liquefaction at a temperature of at least 250° C. for at least 30 minutes, thereby obtaining an increased yield of a biocrude intermediate. The inventors have observed that the effect of grinding is to reduce the yield of charcoal product, as well as to increase the yield of biocrude, with the resulting biocrude / char ratio being more than double that of a comparative control using an identically treated waste feed material, except that it is not subjected to grinding. In an embodiment of this method, the grinding is ball grinding.

[0013] In various embodiments, prior to grinding, the method includes adjusting the waste feed material to a ratio of about 15 wt% solids:95 wt% moisture, 10 wt% solids:90 wt% moisture, or about 15 wt% solids:85 wt% moisture. In various embodiments, the method includes sieving the waste feed material to remove large particles, such as twigs and small branches, prior to ball grinding. In an alternative embodiment, the method does not include sieving the waste feed material prior to the grinding step.

[0014] In various embodiments, the method further includes upgrading the biocrude intermediate to obtain a biofuel. In one embodiment, the upgrading includes subjecting the biocrude intermediate to hydrodeoxygenation at elevated temperature with hydrogen to remove oxygen.

[0015] One aspect of the present invention provides a composition having a high cellulose content of plant waste material comminuted by ball milling to a particle size suitable for hydrothermal liquefaction for a biocrude intermediate. Suitable materials in various embodiments include green waste, lignin waste, and any of the plant-based waste materials described herein. The average particle size is about 100 micrometers (μm) or less, which roughly corresponds to the size of a typical plant cell. This particle size corresponds to a reduced degree of crystallinity of the plant waste. [Brief description of the drawings]

[0016] BRIEF DESCRIPTION OF THE DRAWINGS [Figure 1]Figure 1 shows photographs of green waste (left) and ball milled green waste (second from the left). Green waste is grassy and highly cellulosic; approximately 70% of green waste is cellulose and carbohydrates. These photographs show the extremely small particles obtained by ball milling, which reduces the green waste to a powder. Also shown are photographs of green waste processed by a conventional process, co-solvent enhanced lignin separation (CELF). The carbohydrate fraction from CELF is mostly cellulose, which is soluble in the liquid from the CELF separation, and the lignin precipitates. [Diagram 2] Figure 2 is a series of bar graphs showing the oil yield, in weight percent, from each of the fractions shown in Figure 1. As a control, green waste (2 g) was ball milled and heated, and another sample was ball milled at 60°C for 45 min. The oil yield from the untreated green waste starting material was 18.1 wt% (standard deviation 1.7), and after ball milling the oil yield was 35.4% (standard deviation 4.1). These data show that ball milling increases the oil yield almost two-fold (96%). When the two CELF fractions were each ball milled and heated, 29.9 wt% (1.6) was obtained from the lignin and 22.1 wt% (2.5) from the CELF carbohydrates. [Diagram 3] Figure 3 shows FT-IR spectral analyses performed on samples of oil from green waste sources treated as described in Figure 2, displayed together on the same graph. These are, from the top down, oil from green waste, ball milled green waste, ball milled CELF carbohydrates, and ball milled CELF lignin. The oil from ball milled green waste and from each of the CELF ball milled fractions exhibited the same functionality as the oil from the raw green waste, indicating that the oils contain the same, or very similar, chemical composition. [Figure 4]FIG. 4 is a series of bar graphs showing the number of particles found at sizes ranging from 0.05 mm (millimeters, or 50 micrometers, or 50 microns) down to 0.4 mm for each of the preparations shown in FIG. 1 and for the ball milled CELF carbohydrate. For each of the four preparations, the height of the bar on the ordinate represents the count of particles at the size on the abscissa. From this data it can be seen that the smallest particles were obtained by the method of ball milling the green waste. The mean particle size was 0.16 mm (160 μm or microns, standard deviation 0.09) for the green waste, 0.05 mm or 50 μm (0.04) for the ball milled green waste, 0.10 mm (0.05) for the CELF carbohydrate, and 0.06 (standard deviation 0.03) for the ball milled carbohydrate. Ball milling reduced the mean particle size by more than three-fold from the untreated green waste. [Diagram 5] Figure 5 is a series of bar graphs showing the same data as Figure 4 for green waste, ball milled green waste, and CELF carbohydrate, but also showing data for CELF lignin. The average particle size determined for CELF lignin was 0.08 mm or 80 μm (standard deviation 0.06). [Figure 6] Figure 6 is a series of graphs analyzing the relationship between particle size and oil yield. The graph on the left shows the oil yield as a function of the average particle size in millimeters (mm) determined in Figure 5. The points on the graph fit the equation y=-1.5631x+0.415, assuming the particles are spherical. However, green waste particles appear to be rod-shaped. The graph on the right shows the oil improvement per square area as a function of the average particle size (mm). Oil improvement was calculated as oil yield (%) / 4rπ2, where r=d / 2. As particle size decreases, oil yield increases because the surface area to volume ratio increases, thereby reducing mass transfer limitations and improving the efficiency of oil extraction. [Figure 7]FIG. 7 is a series of X-ray spectroscopy data showing reduced crystallinity for ball milled green waste and ball milled CELF carbohydrate. The left panel displays four spectra together: CELF lignin, CELF carbohydrate, ball milled green waste from the top, and green waste at the bottom. A shift in 2θ intensity to the left is observed for the ball milled green waste compared to the green waste, indicating reduced crystallinity for the ball milled green waste compared to the green waste starting feedstock. The right panel compares ball milled CELF carbohydrate (top trace) to CEF carbohydrate (bottom trace). The data shows that crystallinity is negatively correlated with oil yield. [Figure 8] Figure 8 is a set of four FT-IR analyses of four fractions that collectively display a comparison of ball milling and CELF. From the top are traces of CELF lignin, CELF carbohydrate, green waste, and ball milled green waste. Minor differences in the spectra are observed at 1000 cm-1. This data generally indicates that the ball milling process does not substantially affect the component chemical composition of the resulting oil fractions compared to the large changes in chemical composition due to the CELF process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Detailed Description The method described herein is based on the reactivity and accessibility of the cellulose component, which is the main component of biomass. Crystalline forms of cellulose are less reactive than amorphized forms. Large particles of cellulose are less accessible for reaction. Mechanical grinding reduces the particle size of cellulose, making it more accessible. Additionally, mechanical grinding amorphizes cellulose, which makes it more reactive than its native crystalline form. As a result of mechanical grinding, the yield of the biocrude intermediate increased from about 20 wt% to 40 wt%. The biocrude intermediate was measured at optimal or near-optimal conditions, e.g., 300°C and 60 minutes of reaction time. In contrast to other methods using green waste, the method described herein does not require a catalyst, which becomes inactive over time. Although the method described herein does not require a catalyst, the method also allows for the use of a catalyst to improve the yield of the biointermediate. According to economic projections, a 20 wt% yield corresponds to a fuel selling price of about $5.00 / gallon, and a 40 wt% yield corresponds to a selling price of about $3.00 / gallon.

[0018] Large lawn areas such as golf courses and cemeteries, not to mention suburban residential areas, generate large amounts of grass clippings. Corn monoculture in most of the United States generates corn stover, including leaves and stalks. Sugarcane processing in growing areas such as Texas and Louisiana generates large amounts of plant waste of stalks after crushing. Bulk tissue from banana, one of the world's largest fruit crops, is generated anew each year from perennial roots, and although the producing plant is only annual, the mature plant constitutes a very large biomass after fruit harvest. Cotton is an annual plant, with product only coming from the mature flower, and leaves and stalks remaining each year. Legumes such as soybean, and tobacco generate large amounts of unused plant matter after harvest of the fruit or tender leaves, respectively. These and many other plant materials are suitable large-scale waste feed materials for use in the methods herein.

[0019] One aspect of the invention described herein provides a method for obtaining a biocrude intermediate by hydrothermal liquefaction, the method comprising: obtaining a waste feed material comprising a high cellulose content; grinding the waste feed material to obtain a powdered waste feed material; and subjecting the powdered waste feed material to hydrothermal liquefaction, thereby obtaining a biocrude intermediate.

[0020] In one embodiment of the method, the waste feedstock further comprises at least one of green waste, yard waste, and wood waste. An embodiment of the method further comprises upgrading the biocrude intermediate to obtain a biofuel or bio-oil.

[0021] In one embodiment of the method, the milling of the waste feed material further comprises at least one of the following: ball milling, pin milling, hammer milling, jet milling, two-roll milling, colloid milling, wet disk milling, and vibratory milling. In one embodiment of the method, the biocrude intermediate is greater than 20 wt% of the waste feed material.

[0022] Hydrothermal liquefaction is a very promising method to convert abundant organic wet wastes into biofuels. The biggest bottleneck with hydrothermal liquefaction is producing a biocrude intermediate that can be upgraded to a final fuel. Some wastes, such as yard waste or green waste, are abundant and cheap, but do not provide sufficient biocrude yields to be economically viable. Of course, the increasing carbon dioxide and methane production loads from disposing of these wastes over time will change this calculation.

[0023] Sitotaw et al. (2021, Biomass Conversion and Biorefinery, 22:1-24) review various pretreatments, including the use of enzymes and / or microbial fermentation, used to obtain sugars from plant biomass. The article provides various comminution methods and equipment.

[0024] The method described herein involves mechanically activating the biomass-derived feedstock, thus increasing the yield of biocrude from approximately 20 wt% to 40 wt%. Economic calculations show that this could be the difference between being uncompetitive and being competitive with respect to current fossil fuel prices. The United States alone produces approximately 50 million tons of this type of waste per year, but currently has no good solutions for its utilization.

[0025] The methods provided herein include a mechanical step based on improving the reactivity and accessibility of cellulose-associated lipid membrane and cytoplasmic lipid components, which are the main targets for obtaining oil from biomass. When the feed material is in large particles, these lipid components are less accessible for chemical reactions. Mechanical grinding reduces the particle size, making the cellulose more accessible and amorphizing it, making it more reactive than the native crystalline form. Using optimal conditions (300°C, 60 min reaction time), the yield of the biocrude intermediate increases from about 20 wt% to about 40 wt%. Compared to competitive approaches, these methods do not require expensive catalysts that deactivate over time, nor do they require expensive thermolabile enzymes. It is hypothesized that the methods described herein allow the use of catalysts, which can further increase the yield.

[0026] Mechanical grinding processes are simple, low energy and effective. Increasing biocrude yields from 20wt% to 40wt% makes otherwise unattractive feedstocks such as leaves, fruit and vegetable waste from various industries and leisure and domestic land uses economically viable. Currently, in New England, for example, seasonal disposal of Christmas trees and decorative wreaths is solved by feeding them to goats, but goat utilization may be insufficient to solve the disposal problem while other areas may lack the means for reuse. Crops such as apples generate waste in the form of fallen and bruised fruit. Zoos that feed large herbivores (elephants, zebras, hippos, rhinos, apes) often have substantial vegetable waste stockpiles. Golf courses, cemeteries and highway borders are sources of green waste. Economic projections indicate that a 20 wt% yield equates to a breakeven fuel selling price of approximately $5 / gallon, and a 40 wt% yield equates to approximately $3 / gallon, making the methods described herein competitive.

[0027] Referring now to the drawings, Figure 1 shows the extremely small particles obtained from ball milling, which is a method to powderize green waste. It also shows a photograph of green waste that has been treated by a conventional, but different, process, Co-solvent Enhanced Lignin Separation (CELF). The solvent commonly used for CELF is tetrahydrofuran.

[0028] Figure 2 shows that the oil yield from the starting feedstock green waste was 18.1 wt% while the oil yield after ball milling was 35.4%, indicating that ball milling increased the oil yield by 96%, almost doubling the yield. The doubling of yield is very significant as recovery is unlikely to be 100%. Furthermore, only 29.9 wt% was obtained from the ball milled fraction obtained from CELF, compared to 22.1 wt% from the CELF carbohydrate without ball milling. These data show the generality of increasing yields from plant materials by the milling process, which breaks down the material in addition to using heat to obtain biocrude.

[0029] Figure 3 is a Fourier transform infrared (FT-IR) spectrum analysis, which shows that the oil from ball milled green waste exhibits the same functionality as the oil from raw green waste, indicating that these oils contain the same or very similar chemical composition.

[0030] The data in Figure 4 show that the smallest particles were obtained from the ball milling of green waste and the ball milled flour of CELF carbohydrate, while the largest particles were found in the untreated green waste and CELF carbohydrate. The average particle size was 0.16 mm for green waste, 0.05 mm for ball milled green waste, 0.10 mm for CELF carbohydrate, and 0.06 mm for ball milled carbohydrate. The particle sizes from ball milling, i.e., 50 and 60 micrometers, correspond to the order of average particle size and size of plant cells, indicating that the ball milling process reduced the plant waste to a unit for cellulose production. The data in Figures 4 and 5 show that ball milling reduced the particle size of the green waste by 70%, compared to a 44% reduction in particle size from the CELF process alone.

[0031] Most importantly, Figure 6 examines the relationship between particle size and oil yield. The graph on the left shows oil yield as a function of average particle size in millimeters (mm) as determined in Figure 5. The points on the graph fit the equation y=-1.5631x+0.415, assuming the particles are spherical. However, particles from the untreated green waste feed material appear to be rod-shaped. The graph on the right shows the oil improvement per square area as a function of average particle size (mm). Oil improvement is calculated as Oil Yield (%) / 4rπ 2 where r=d / 2. Reducing particle size increases the surface area to volume ratio, thereby reducing mass transfer limitations and improving the efficiency of oil extraction by the process steps herein, thereby increasing oil yield.

[0032] FIG. 7 is a series of X-ray spectroscopy data showing the reduction in crystallinity of ball milled green waste and ball milled CELF carbohydrate. For methods involving cellulose crystallography, see Park, S., et al., Biotechnology for Biofuels, 3:10 (2010). A left shift in 2θ intensity was observed for ball milled green waste compared to non-ball milled green waste, indicating a reduction in crystallinity of ball milled green waste compared to the green waste starting feedstock. These data indicate that the observed reduction in crystallinity correlates with an increase in oil yield for the plant materials analyzed. The cell membrane lipids on the inside of the various cellulose layers of the plant cells, including the polyphenolic lignin compounds on the outside, may be more accessible to liberation by the heat treatment after ball milling, leading to improved recovery after this pretreatment process and improved biocrude yield.

[0033] The FT-IR analysis in FIG. 8 comparing ball milling of the plant material and the CELF fraction generally shows that the ball milling process does not substantially affect the chemical composition of the resulting oil fraction.

[0034] It is understood that any feature described in connection with any one of the embodiments provided herein can be used alone or in combination with other features described, and can also be used in combination with any other feature or features of the embodiments, or any other combination of the embodiments. Moreover, equivalents and modifications not described above can also be employed without departing from the scope of the invention as set forth in the appended claims.

[0035] The invention having been fully described is further illustrated by the following claims. Those skilled in the art will recognize, or be able to ascertain with no more than routine experimentation, numerous equivalents to the specific methods described herein. Such equivalents are within the scope of the invention and claims. The contents of all references cited in this application, including issued patents and published patent applications, are hereby incorporated by reference in their entirety.

Claims

1. 1. A method for obtaining a biocrude intermediate by hydrothermal liquefaction, the method comprising: obtaining a waste feed material comprising a high cellulose content; grinding the waste material to obtain a powdered waste feed material; and subjecting said powdered waste feedstock to hydrothermal liquefaction at a temperature selected from a temperature greater than about 250° C. in the absence of a catalyst or a temperature greater than about 150° C. in the presence of a catalyst, thereby obtaining a biocrude intermediate. The method includes:

2. 2. The method of claim 1, wherein the waste feedstock further comprises at least one of green waste, garden waste, zoo waste feedstock, zoo herbivore feces, floriculture waste, agricultural waste, beverage industry waste such as grape pomace, food waste, inedible vegetable waste, marine algae, freshwater algae, lignin from paper or sugar manufacturing, and wood waste such as sawdust.

3. 10. The method of claim 1, further comprising upgrading the biocrude intermediate to obtain a biofuel or a biooil.

4. 4. The method of claim 3, wherein upgrading comprises subjecting the biocrude intermediate to high temperature hydrodeoxygenation with hydrogen, thereby removing oxygen.

5. 10. The method of claim 1, wherein the grinding of the waste feed material further comprises at least one of ball milling, pin milling, hammer milling, jet milling, two-roll milling, colloid milling, wet disk milling, and vibratory milling.

6. 10. The method of claim 1, wherein the resulting biocrude intermediate is greater than 20 wt % of the waste feed material, greater than 25 wt % of the waste feed material, or greater than 30 wt % of the waste feed material.

7. 10. The method of claim 1, wherein subjecting the pulverulent waste feed material to hydrothermal liquefaction further comprises treating the pulverulent waste feed material at a temperature of from about 250°C to about 400°C.

8. 8. The method of claim 7, wherein the time period for providing is at least about 25-55 minutes, 30-60 minutes to about 35-65 minutes.

9. 10. The method of claim 1, wherein the grinding results in particles of the pulverulent waste feed material having a size of less than about 0.2 mm, less than 0.15 mm, less than 0.10 mm, less than 0.05 mm (50 μm), less than 0.025 mm (25 μm), or less than about 0.01 mm (10 μm).

10. 10. The method of claim 1, wherein the grinding results in particles of the pulverulent waste feed material having a reduced degree of crystallinity as analyzed by powder X-ray diffraction.

11. 2. The method of claim 1, wherein the steps are carried out in the absence of exogenously added enzymes and / or in the absence of catalysts.

12. 1. A method for increasing the yield of a biocrude intermediate from plant waste by hydrothermal liquefaction, the method comprising: obtaining a waste feed material comprising a high cellulose content; grinding the waste feed material to obtain a powdered waste feed material having a reduced particle size; and subjecting said powdered waste feed material to hydrothermal liquefaction at a temperature of at least about 250° C. for at least about 30 minutes, thereby obtaining an increased yield of said biocrude intermediate. The method includes:

13. 13. The method of claim 12, wherein the resulting biocrude / charcoal ratio, along with the reduced yield of charcoal product, is observed to be more than twice that of an otherwise identical waste feed material that is not subjected to said comminution step for size reduction.

14. 13. The method of claim 12, comprising conditioning the waste feed material to a ratio of about 15 wt.% solids:95 wt.% moisture, 10 wt.% solids:90 wt.% moisture, or about 15 wt.% solids:85 wt.% moisture prior to ball milling.

15. 13. The method of claim 12, further comprising sieving the waste feed material prior to grinding, thereby removing large particles.

16. The method of claim 12, wherein the milling is ball milling.

17. 13. The method of claim 12, further comprising upgrading the biocrude intermediate to obtain a biofuel.

18. 20. The method of claim 17, wherein upgrading comprises subjecting the biocrude intermediate to high temperature hydrodeoxygenation with hydrogen, thereby removing oxygen.

19. A composition comprising a high cellulose content plant waste material or lignin waste comminuted by ball milling to a particle size suitable for hydrothermal liquefaction for a biocrude intermediate.

20. 20. The composition of claim 19, wherein the particle size has an average particle size of less than 100 micrometers (100 μm).

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